ARTICLE | doi:10.20944/preprints202308.1201.v1
Subject: Medicine And Pharmacology, Pharmacy Keywords: Methicillin-resistant Staphylococcus aureus; poly-amidoamine dendrimers (PAMAM); anti-virulence agent, accessory gene regulator; histidine kinase inhibitor.
Online: 16 August 2023 (20:32:54 CEST)
Methicillin-resistant Staphylococcus aureus (MRSA) exerts a considerable concern in healthcare and the community. Globally MRSA strains cause numerous infections with high morbidity and mortality rates. The success of MRSA is a result of the extensive production of virulence factors. With the limited treatment options for the MRSA infection and growing resistance problem, an urgent call is needed to search for an alternative to antibiotics. One of the promising strategies is targeting the quorum sensing (QS) system, of the MRSA, by using a dendrimer loaded with kinase inhibitor peptide. This study formulates a poly-amidoamine dendrimers (PAMAM) G4 dendrimers loaded with Quorum Quencher (QQ), QQ3 peptide which is a Histidine Kinase inhibitor. The physicochemical properties of the formula were characterized using different in-vitro analysis method such as Zetasizer and transmission electron microscope (TEM). The antibacterial activity and anti-virulence effect of the formula was tested against MRSA and different mutant stains using growth assay, haemolysis assay and biofilm assay. Overall, QQ3-G4 complex showed antibacterial and anti-virulence activity and it can be a potential alternative treatment to overcome antimicrobial resistance and treat MRSA infection.
ARTICLE | doi:10.20944/preprints202306.1626.v1
Subject: Medicine And Pharmacology, Pharmacy Keywords: Methicillin-resistant Staphylococcus aureus; biofilm; Antimicrobial agent; eugenol; Raman spectroscopy.
Online: 22 June 2023 (12:40:14 CEST)
Prevalence of antimicrobial-resistant bacteria has become a major challenge worldwide. Methicillin-resistant Staphylococcus aureus (MRSA)—a leading cause of infections—forms biofilms on polymeric medical devices and implants, increasing their resistance to antibiotics. Antibiotic administration before biofilm formation is crucial. Raman spectroscopy was used to assess MRSA biofilm development on solid culture media from 0 to 48 h. Biofilm formation was monitored by measuring DNA/RNA-associated Raman peaks and protein/lipid-associated peaks. The search for an antimicrobial agent against MRSA biofilm revealed that Eugenol was a promising candidate as it showed significant potential for breaking down the biofilm. Eugenol was applied at different times to test the optimal time for inhibiting MRSA biofilms, and the Raman spectrum showed that the first 5 h of biofilm formation was the most antibiotic-sensitive time. This study investigated the performance of Raman spectroscopy coupled with Principal Component Analysis (PCA) to identify planktonic bacteria from biofilm conglomerates. Raman analysis, microscopic observation, and quantification of the biofilm growth curve indicated early adhesion from 5 to 10 h of incubation time. Therefore, Raman spectroscopy can help in monitoring biofilm formation on a solid culture medium and performing rapid antibiofilm assessments with new antibiotics during the early stages of the procedure.
ARTICLE | doi:10.20944/preprints202302.0072.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Prophage; Endolysin; Staphylococcus aureus; Methicillin-resistant Staphylococcus aureus; Antibiotic-resistance; Bovine mastitis
Online: 3 February 2023 (10:35:34 CET)
The increasing prevalence of methicillin-resistant S. aureus (MRSA) in the dairy industry has become a fundamental concern. Endolysins are bacteriophage-derived peptidoglycan hydrolases that induce the rapid lysis of host bacteria. We investigated endolysin candidates with lytic activity against MRSA and evaluated the lytic activity of the endolysin candidate against S. aureus and MRSA. To identify endolysins, we used the following bioinformatic strategy: (1) retrieval of genetic information, (2) annotation, (3) selection of MRSA, (4) selection of endolysin candidates, and (5) evaluation of protein solubility. We then characterized the endolysin candidate under various conditions. Approximately 67% of S. aureus was detected as MRSA and a total of 114 putative endolysins were found. The 114 putative endolysins were divided into three groups based on their combination of conserved domains. Considering the protein solubility, we selected putative endolysins 177 and 117. Putative endolysin 117 was successfully overexpressed and renamed LyJH1892. LyJH1892 lysed approximately 85% of S. aureus. LyJH1892 showed more potent lytic activity against MRSA than normal S. aureus (relative lytic activity > 125%). LyJH1892 showed broad lytic activity against coagulase-negative Staphylococci (CNS). In conclusion, These findings provide a rapid and useful strategy for the development of specific endolysins against antibiotic-resistant bacterial strains.
CASE REPORT | doi:10.20944/preprints202212.0128.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: infective endocartidis; methicillin-resistant Staphylococcus aureus; mitral valve
Online: 7 December 2022 (10:47:17 CET)
Infective endocarditis (IE) is a life-threatening condition caused by infection within the endocardium of the heart, and commonly involves the valves. The subsequent cascading inflammation leads to the appearance of a highly friable thrombus that is large enough to become lodged within the heart chambers. As a result, fever, fatigue, heart murmurs, and embolization phenomena may be seen in patients with IE. Embolization results in the seeding of bacteria, and obstruction of circulation, causing cell ischemia. Of concern, bacteria with the potential to gain pan-drug resistance, such as methicillin-resistant Staphylococcus aureus (MRSA), are increasingly being identified as the causative agent of IE in hospitals and among intravenous drug abusers. We retrospectively reviewed de-identified clinical data to summarize the clinical course of a patient with MRSA isolated using an automated blood culture system. At the time of presentation, the patient showed a poor consciousness level, and the calculated Glasgow scale was 10/15. A high-grade fever with circulatory shock indicated an occult infection, and a systolic murmur was observed with peripheral signs of embolization. This case demonstrated the emerging threat of antimicrobial resistance in the community, and revealed clinical findings of IE that may be helpful to clinicians for the early recognition of the disease. The management of such cases requires a multi-specialty approach, which is not widely available in small island developing states like the Maldives.
ARTICLE | doi:10.20944/preprints202109.0193.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: bioassay; chromatography; folkloric medicine; methicillin-resistant Staphylococcus aureus; Senna alata; spectroscopy
Online: 13 September 2021 (07:21:28 CEST)
Senna alata (Linn) Roxb. plant is widely used to manage various infections in folkloric medicine. Methicillin-resistant Staphylococcus aureus (MRSA) infection continues to be a major global public health problem. This study aims to investigate the bioactive components of S. alata leaves active against MRSA. The leaves of S. alata were sequentially extracted and fractionated using standard methods and screened for activities against MRSA. The diethyl ether active thin layer chromatography (TLC) spot was subjected to infrared (IR) and gas chromatography-mass spectroscopic (GC-MS) studies. The aqueous extract and diethyl ether fraction of S. alata leaves elicited the highest activity against the MRSA. The GC-MS analysis of the fraction produced 15 eluates; only the sub-fraction 13 was effective. The TLC analysis of the sub-fraction 13 revealed three spots; only the second spot produced activity. The GC-MS result of the spot showed six peaks. The spectral results for peak 3 match the data from the IR study suggestive of 9-octadecenoic acid methyl ester. Senna alata leaves possess bioactive compounds closely related to 9-octadecenoic acid methyl ester with potent antibacterial activity against MRSA.
ARTICLE | doi:10.20944/preprints202306.2105.v1
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: Methicillin-resistant Staphylococcus aureus; healthcare workers; whole genome sequencing; low-or middle-income countries
Online: 29 June 2023 (12:46:22 CEST)
Methicillin-resistant Staphylococcus aureus (MRSA) constitutes a serious public health concern with a considerable impact on patients' health and substantial healthcare costs. In this study, patients, and healthcare workers (HCWs)from six public hospitals in Benin were screened for MRSA. Strains were identified as MRSA using conventional microbiological methods in Benin and confirmed using Matrix-Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) mass spectrometry in Belgium. Whole genome sequencing (WGS) was used on confirmed MRSA isolates to characterize their genomic content and study their relatedness. In total,304 and 61 samples were collected from patients and HCWs, respectively. The mecA gene was detected in all isolates. The isolates were assigned to five sequence types (STs), with ST8 (55.6%, n=15), ST152 (18.52%, n=5), and ST121 (18.52%, n=5) being the most common. All isolates carried multiple virulence genes, including genes encoding the Panton-Valentine leukocidin toxin (48.15%, n=13) and the test gene (29.63%, n=8) associated with toxic shock syndrome. The presence of strains carrying numerous genomic features associated with antibiotic resistance and virulence in HCWs is a major public health concern. This study highlights the need to implement a multimodal strategy for reducing the risk of cross-transmission of MRSA in hospitals.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: DPTM; Methicillin-resistant Staphylococcus aureus (MRSA); Antibacterial activity; Murine skin wound model; MIC
Online: 12 April 2021 (12:18:08 CEST)
Staphylococcus aureus (S. aureus) is a major human pathogen that requires new antibiotics with unique mechanism. A new pleuromutilin derivative, 14-O-[(4,6-Diaminopyrimidine-2-yl) thioacetyl] mutilin (DPTM), has been synthesized and proved as a potent antibacterial agent using in vitro and in vivo assays. In the present study, DPTM was further in vitro evaluated against Methicillin-resistant Staphylococcus aureus (MRSA) isolated from dairy farms and outperformed tiamulin fumarate, a pleuromutilin drug used for veterinary. Moreover, a murine skin wound model caused by MRSA infection was established and the healing effect of DPTM was investigated. The results showed that DPTM could promote the healing of MRSA skin infection, reduce the bacterial burden of infected skin MRSA and decrease the secretion of IL-6 and TNF-α inflammatory cytokines in plasma. These results provided the basis for further in-depth drug targeted studies of DPTM as a novel antibacterial agent.
ARTICLE | doi:10.20944/preprints201810.0293.v1
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: MRSA, MSSA, Staphylococcus aureus, mortality, gender, Methicillin-resistant Staphylococcus aureus, infectious disease, prevention
Online: 15 October 2018 (09:35:59 CEST)
Average of 41,900 patients are diagnosed annually with staphylococcus bacterial infection in California, 24,089 patients have Methicillin-resistant Staphylococcus Aureus (MRSA) and 17,810 patients have Methicillin-Sensitive Staphylococcus (MSSA). This paper demonstrates that there is a difference in mortality rate due to staphylococcus infection between males and females (P-value<0.05, CI 95%). Male patient diagnosed with S. aureus has 1.3 chance of mortality incidence than female patient. In addition, MRSA infection rate is 1.4 times MSSA infection (P-value<0.05, CI 95%), but the gap of infection is decreasing; however, mortality of both infections combined are more than threefold greater compared to three decades ago.
REVIEW | doi:10.20944/preprints202304.0180.v1
Subject: Medicine And Pharmacology, Pharmacy Keywords: Methicillin-resistant Staphylococcus aureus; MRSA; antibiotic resistance mechanism; novel therapeutic approaches
Online: 11 April 2023 (03:20:45 CEST)
Staphylococcus aureus (S. aureus), particularly Methicillin-resistant S. aureus (MRSA), is a life-threatening pathogen that causes a variety of infections in hospital and community settings. It poses a significant risk and challenge for global health that hinders our ability to control and treat bacterial infections. Recently, the emergence and spread of variant strains of bacteria, misuse of the limited available options of effective antibiotics, spread of fake drugs, and climate change that increased the contact between humans and animals’ populations carrying different bacterial has significantly increased the incidence of Multi-Drug Resistance strains (MDR). This in turn, has created a severe problem in the infection control treatment of S. aureus infected patients. Treatment options for MRSA infection are increasingly limited and complicated. Unfortunately, different strains of MRSA are showing tolerance and resistance toward vancomycin, which is the standard of care for complicated MRSA. Therefore, it is crucial now to invest developing new effective anti-biotics and synergies, develop and implement national action plans for the management of an-tibiotic resistance, as well as improving our understanding of the antimicrobial resistance mechanisms. Here, in this review we explain the main mechanisms of antibiotic resistance in MRSA and describes different approaches to manipulate it in MRSA, providing a basis for de-signing effective drugs, and shedding some light on the evolution of S. aureus.
ARTICLE | doi:10.20944/preprints202311.1379.v1
Subject: Medicine And Pharmacology, Pharmacy Keywords: antibacterial activity; antistaphylococcal synergistic effect; methicillin resistant S. aureus; musculoskeletal infections; non-steroidal anti-inflammatory drugs
Online: 22 November 2023 (06:33:47 CET)
Musculoskeletal infections (MIs) are among the most difficult-to-treat staphylococcal diseases. The limited availability of effective antibiotics has encouraged the development of innovative strategies such as combinatory therapy to combat MI. The aim of this study was to investigate the in vitro antistaphylococcal activity of anti-inflammatory and the antimicrobial combinatory effect of celecoxib with oxacillin. The minimum inhibitory concentrations (MICs) of 17 anti-inflammatory drugs were determined for standard strains and clinical isolates of S. aureus strains, counting methicillin-resistant strains (MRSA), by the broth microdilution method. The fractional inhibitory concentration indices (FICIs) were evaluated by the checkerboard assays. Celecoxib produced the most potent antistaphylococcal effect against all the tested strains (MIC ranging from 32 to 64 mg/mL), followed by diacerein against MRSA3 and MRSA ATCC 33592 (MIC 64 mg/mL). Several synergistic effects were observed for tested S. aureus strains, including MRSA (FICI ranging from 0.087 to 0.471). The strongest synergistic interaction (FICI 0.087) was obtained against MRSA ATCC 33592 at a celecoxib concentration of 2 mg/mL with a 19-fold oxacillin MIC reduction (from 512 to 26.888 mg/mL). This is the first report on the antistaphylococcal combinatory effect of celecoxib with oxacillin. Our findings suggest celecoxib and its combination with oxacillin as perspective agents for research focused on the development of novel therapies for MI caused by S. aureus. Thus, this study presents novel findings that celecoxib could, in some cases, resensitise MRSA strains to become susceptible to certain β-lactams (e.g., oxacillin) not previously tested.
ARTICLE | doi:10.20944/preprints202311.1974.v1
Subject: Animal Science, Veterinary Science And Zoology, Biology And Life Sciences Keywords: antibiofilm effect; enterocin; methicillin-resistance; rabbit; Staphylococcus aureus
Online: 30 November 2023 (10:16:49 CET)
There is a major problem with the rising occurrence of highly virulent and multiply-resistant strains, including methicillin-resistant Staphylococcus aureus (MRSA), because of their difficult treatment. This study aimed to evaluate the antibacterial and antibiofilm effect of new enterocins (Ent) against potential pathogenic MRSA strains isolated from rabbits. Staphylococci (n =110) were identified with PCR and screened for methicillin/oxacillin/cefoxitin resistance (MR) using the disk diffusion method and the PBP2' Latex Agglutination Test Kit. Enzyme production, hemolysis, DNase activity, slime production, and biofilm formation were tested in MRSA strains. The susceptibility of MRSA to eight partially-purified enterocins (Ent) produced by E. faecium and E. durans strains was checked using agar spot tests. The antibiofilm activity of Ents was tested using a quantitative plate assay. Out of 14 MRSA, PBP testing confirmed MR in 8 strains. The majority of MRSA showed DNase activity and β-hemolysis. Slime production and moderate biofilm formation were observed in all strains. MRSA were susceptible to tested Ents (100–12800 AU/mL; except Ent4231). The antibiofilm effect of Ents (except Ent4231) was noted in the high range (64.9-97.0%). These results indicate that enterocins offer a promising option for the prevention and treatment of bacterial infections caused by biofilm-forming MRSA.
CASE REPORT | doi:10.20944/preprints202007.0219.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: Preterm infant; Necrotizing pneumonia; Methicillin-Resistant Staphylococcus Aureus (MRSA); Pneumatoceles; Linezolid; Vancomycin; Rifampicin
Online: 11 July 2020 (02:10:45 CEST)
Necrotizing pneumonia due to Methicillin-Resistant Staphylococcus Aureus (MRSA) is devastating and difficult to treat in preterm infants. We report a case of severe MRSA necrotizing pneumonia in a preterm infant. As an add-on rescue therapy to vancomycin, linezolid rapidly cured this case after the failure of vancomycin plus rifampicin. This rapid cure suggests that adjunctive rather than rescue linezolid may be considered in such cases.
ARTICLE | doi:10.20944/preprints202104.0086.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: DNA sensor; point of care diagnostics; methicillin-resistant Staphylococcus aureus; label free biosensor; AC electrokicetics
Online: 5 April 2021 (10:11:51 CEST)
Biosensors have shown great potential in realizing rapid, low cost and portable on-site detection for diseases. This work reports the development of a new bioelectronic sensor called AC electrokinetics-based capacitive (ABC) biosensor, for the detection of genomic DNA (gDNA) of methicillin-resistant Staphylococcus aureus (MRSA). The ABC sensor is based on interdigitated microelectrodes biofunctionalized with oligonucleotide probes. It uses a special AC signal for direct capacitive monitoring of topological change on nanostructured sensor surface, which simultaneously induce dieletrophoretic enrichment of target gDNAs. As a result, rapid and specific detection of gDNA/probe hybridization can be realized with high sensitivity. It requires no signal amplification such as labelling, hybridization chain reaction, or nucleic acid sequence-based amplification. This method involves only simple sample preparation. After optimization of nano-structured sensor surface and signal processing, the ABC sensor demonstrated fast turnaround of results (~10 s detection), excellent sensitivity (a detection limit of 4.7 DNA copies /µL MRSA gDNA) and high specificity, suitable for point of care diagnosis. As a bioelectronic sensor, the developed ABC sensors can be easily adapted for detection of other infectious agents.
ARTICLE | doi:10.20944/preprints202103.0024.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Methicillin-resistant Staphylococcus aureus; Multidrug resistance; mecA gene; Frozen chicken meat; Bangladesh
Online: 1 March 2021 (13:56:33 CET)
Infections by methicillin-resistant Staphylococcus aureus (MRSA) are continuously expanding within the community. Chicken meat is usually contaminated by MRSA, and this contaminated chicken meat is an important source of foodborne infections in humans. In this study, a cross-sectional supershop survey was conducted to determine the prevalence and antimicrobial resistance pattern of MRSA in 113 domestic frozen chicken meat samples purchased from nine branded supershops available in five divisional megacities of Bangladesh. The study also focused on the determination of methicillin resistance gene in MRSA isolates. S. aureus was identified by standard culture-based and molecular methods, and subjected to antimicrobial susceptibility testing. MRSA was screened by cefoxitin disk diffusion test. Methicillin resistance gene was identified by PCR. Of samples, 54.9% were positive for S. aureus, and, of these, 37.1% isolates were identified as MRSA. All the isolates were multidrug resistant (MDR): 52.2% were resistant to 6−8 antimicrobial classes, and 47.8% isolates to 9−12 classes. Three (3.2%) isolates of S. aureus were possible extensively drug resistant. The highest rates of resistance were observed against cefoxitin (100%), followed by nalidixic acid, ampicillin and oxacillin (97.7%), colistin (91.3%), amoxicillin-clavulanic acid and amoxicillin (87%), penicillin-G and cloxacillin (82.6%), oxytetracycline (78.3%) and cefixime (73.9%). Screening of methicillin resistance gene revealed that 43.5% isolates of MRSA were positive for mecA gene. The high prevalence of MDR MRSA in frozen chicken meat samples in this study emphasizes the need for better sanitary education of food handlers in hygienic practices focusing on their potential role as reservoirs and spreaders of MRSA.
ARTICLE | doi:10.20944/preprints201904.0059.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: methicillin-resistant Staphylococcus aureus; methicillin-sensitive Staphylococcus aureus; statistics; superbug; hormone; prevention
Online: 5 April 2019 (11:46:16 CEST)
In California, an average of 41,900 patients are diagnosed annually with Staphylococcus bacterial infection; out of these, 24,090 patients have methicillin-resistant Staphylococcus aureus (MRSA) infection and 17,810 patients have methicillin-sensitive Staphylococcus aureus (MSSA) infection. The aim of this paper is to find out whether there is a significant difference in strain dominancy and in what direction. The paper gathered and analyzed data for period of five years of infection rate due to Staphylococcus aureus. This study indicates that a significant difference in dominancy exists, the MRSA infection rate (an average of five years period) is 1.35 times higher than the MSSA infection rate (P-value < 0.05, CI: 95%), but the gap between the two infection rates is decreasing. The infection rate of both MRSA and MSSA is in a path of decline.
REVIEW | doi:10.20944/preprints202310.0197.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: Carbapenem-resistant Acinetobacter baumannii (CRAB); Methicillin-resistant Staphylococcus aureus (MRSA); Carbapenem-resistant Enterobacterales (CRE); Extended-spectrum Beta Lactamase producing Enterobacterales (ESBL); Multidrug-resistant (MDR) Pseudomonas aeruginosa
Online: 4 October 2023 (07:23:22 CEST)
Post-COVID-19 bacterial infections are a significant threat to global health, mainly due to the overuse and misuse of antibiotics. The review highlights the importance of using antibiotics judiciously and following appropriate guidelines and recommendations. The article also examines the potential indirect contribution of steroids to antibiotic resistance through immune suppression in severe cases of COVID-19. Anti-microbial resistance (AMR) is one of the leading causes of death worldwide that continues as a silent pandemic caused by the major AMR superbug includes Carbapenem-resistant Acinetobacter baumannii (CRAB), Methicillin-resistant Staphylococcus aureus (MRSA), Carbapenem-resistant Enterobacterales (CRE), Extended-spectrum Beta Lactamase producing Enterobacterales (ESBL) which is resistant to cephalosporin and Multidrug-resistant (MDR) Pseudomonas aeruginosa. Ongoing surveillance and monitoring of antibiotic use and resistance helped to minimize the risk of antibiotic resistance and shrink it from pandemic to endemic.
ARTICLE | doi:10.20944/preprints202303.0455.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: resistant bacteria; COVID-19 pandemic era; antibiotics
Online: 27 March 2023 (08:59:13 CEST)
Abstract: The overuse of antibiotic prophylaxis during the COVID-19 pandemic would have led to the devel-opment of antibiotic-resistant bacterial strains, thereby increasing the epidemiological burden of antimicrobi-al resistance. The aim of this study was to determine the prevalence and antibiotic resistance pattern of bacte-ria isolated in 02 referral health facilities in Yaoundé before and during the COVID-19 pandemic era. We conducted a retrospective study over a period of 03 years (from 1 January 2019 to 31 December 2021) in the bacteriology units of the Central and General Hospitals of Yaoundé, Cameroon. The review of the services' registers was done to record bacterial isolates (Streptococcus, Staphylococcus, Neisseria meningitidis and Entero-bacteriaceae) as well as their susceptibility to selected, specific and highly potent antibiotics: Cefixime, Azythromycin and Erythromycin. The relationship between each group of resistant bacteria and the antibiotic of interest was determined by simple linear regression; the comparison of the prevalences of before (2019) and during 2 consecutive years of the COVID-19 pandemic onset (2020 and 2021) was done by the Chi2 test of in-dependence. In all, 426 bacterial strains were included. It appeared that the highest number of bacteria iso-lates and lowest rate of bacterial resistance were recorded during the pre-COVID 2019 period in 2019 (160 isolates vs. 58.8% resistance rate). Conversely, lower bacteria stains but greater resistance burden were rec-orded during the pandemic era (2020 and 2021) with the lowest bacteria amount and peak of bacteria re-sistance registered in 2020, the year of COVID-19 onset (120 isolates vs. 70% resistance in 2020 and 146 iso-lates vs.58.9% resistance in 2021). In contrast to almost all others groups of bacteria where the resistance burden was quite constant over years, the Enterobacteriaceae exhibited greater resistance rate during the pandemic period [60%(48/80) in 2019 to 86.9%(60/69) in 2020 and 64.5%(61/95) in 2021)]. Concerning antibiotics, unlike Erythromycin, Azythromycin related resitance increased during the pandemic period and the resistance to Cefixim tends to decrease the year of the pandemic onset (2020) and re-increase one year therafter. A significant association was found between resistant Enterobacteriaceae strains and Cefixime (R= 0.7; P-value= 0.0001) and also, between resistant Staphylococcus strains and Erythromycin (R= 0.8; P-value= 0.0001). It could be that the more frequent use of these antibiotics has increased resistance rate especially in Enterobacteriaceae. Anticromicrobial resistance should be closely monitor during and after COVID pandemic era.
ARTICLE | doi:10.20944/preprints202201.0131.v1
Subject: Medicine And Pharmacology, Other Keywords: methicillin-resistant Staphylococcus aureus; Matrix-Assisted Laser Desorption/Ionization Time-of-Flight; antibiotic susceptibility test; artificial intelligence
Online: 10 January 2022 (19:01:57 CET)
Combining Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) spectra data and artificial intelligence (AI) has been introduced for rapid prediction on antibiotic susceptibility test (AST) of S. aureus. Based on the AI predictive probability, the cases with probabilities between low and high cut-offs are defined as “grey zone”. We aimed to investigate the underlying reasons of unconfident (grey zone) or wrong predictive AST. A total 479 S. aureus isolates were collected, analyzed by MALDI-TOF, and AST prediction, standard AST were obtained in a tertiary medical center. The predictions were categorized into the correct prediction group, wrong prediction group, and grey zone group. We analyzed the association between the predictive results and the demographic data, spectral data, and strain types. For MRSA, larger cefoxitin zone size was found in the wrong prediction group. MLST of the MRSA isolates in the grey zone group revealed that uncommon strain types composed 80%. Amid MSSA isolates in the grey zone group, the majority (60%) was composed of over 10 different strain types. In predicting AST based on MALDI-TOF AI, uncommon strains and high diversity would contribute to suboptimal predictive performance.
REVIEW | doi:10.20944/preprints202305.1078.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: bacterial resistance; methicillin-resistant S. aureus (MRSA); multi drug resistant (MDR) bacteria; Cannabis sativa; phytocannabinoids (PCs); endocannabinois (ECs); synthetic cannabinoids (SCs); synthetic procedures; cannabichromene (CBC); cannabigerol (CBG); cannabidiol (CBC)
Online: 16 May 2023 (04:29:36 CEST)
Due to the rapid emergence of multi drug resistant (MDR) pathogens against which current an-tibiotics are no longer functioning, severe infections are becoming practically untreatable. Con-sequently, the discovering of new classes of effective antimicrobial agents with novel modes of action is becoming increasingly urgent. The bioactivity of Cannabis sativa, an herbaceous plant used for millennia for medicinal and recreational purposes, is mainly due to its content in phytocan-nabinoids (PCs). Among the 180 PCs detected, cannabidiol (CBD), Δ8 and Δ9-tetrahydrocannabinols (Δ8-THC and Δ9-THC), cannabichromene (CBC), cannabigerol (CBG), cannabinol (CBN) and some their acidic precursors have demonstrated from moderate to potent antibacterial effects against Gram-positive bacteria (MICs 0.5–8 µg/mL), including methicillin-resistant Staphylococcus aureus (MRSA), epidemic MRSA (EMRSA), as well as fluoroquinolones and tetracycline-resistant strains. Particularly, the not psychotropic CBG was also capable to inhibit MRSA biofilm formation, to eradicate that mature, and to rapidly exterminate MRSA persiters cells. On this scenario, CBG, as well as other minor not psychotropic PCs, such as CBD, and CBC could represent promising compounds for developing novel antibiotics with high therapeutic potential. Anyway, further studies are necessary, needing abundant quantities of such PCs, scarcely provided naturally by Cannabis plants. Here, after an extensive overture on cannabinoids including their reported an-timicrobial effects, aiming at easing the synthetic production of the necessary amounts of CBG, CBC and CBD for further studies, we have, for the first time, systematically reviewed the synthetic pathways utilized for their synthesis, reporting both reaction schemes and experimental details.
REVIEW | doi:10.20944/preprints202307.0741.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Fermented foods; Antibiotic-resistant bacteria; Antibiotic-resistant genes
Online: 12 July 2023 (09:30:13 CEST)
Fermented food products are widely consumed for their nutritional and health-promoting properties earning them a central place in diets around the globe. However, these foods can present a paradox, as they have the potential to harbor not only beneficial probiotics but also antibiotic-resistant (AR) microbes and genes. The impact of AR in fermented foods has far-reached implications, such as its potential effects on human health, repercussions in the food industry, and environmental consequences. An in-depth analysis of AR in fermented foods, including dairy products, fermented fruits and vegetables, meat products, and beverages, would provide insights into the extent and ramifications of the issue with these foods. Therefore, this review systematically presents the status of AR in fermented foods, with a particular focus on AR bacteria and genes within this category of food products. The review also highlights the complexities of AR in fermented foods, emphasizing the role of bacterial adaptation during the fermentation process and the dynamics of bacterial gene transfer. Various contributing factors to AR are brought into focus, including intrinsic resistance among bacteria in fermented foods and the potential risk of contamination with pathogenic bacteria. Moreover, this review presents a range of mitigation strategies, from the development of novel antimicrobials to advances in fermentation technology and regulatory control. This comprehensive perspective on the intricate interplay between AR and fermented food will potentially pave the way for more targeted research and mitigation strategies in this critical area.
ARTICLE | doi:10.20944/preprints202308.0869.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: donkey; Escherichia coli; antibiotic resistant
Online: 10 August 2023 (13:21:14 CEST)
Escherichia coli (E. coli) is a common pathogen in veterinary clinical infections, typically not causing disease. However, under certain conditions, it can cause severe diarrhea, septicemia, and respiratory infections in domestic animals. Here, we report a large-scale mortality event in young donkeys, caused by E. coli infection in a farm with a herd of 340 donkeys, of which over 100 were under 4 months old. The characteristics of the E. coli strain were determined through clinical observation, complete blood count, blood biochemical analysis, H&E staining, histopathological examination, 16S rRNA analysis, and antibiotic sensitivity testing. A mice experiment using the isolated bacteria was also conducted, resulting in the onset of clinical and pathological symptoms similar to those observed in the donkeys. Molecular Evolutionary Genetic Analysis (MEGA) showed that the isolated bacteria, named CEG-GZL20, shared 99.98% sequence identity with E. coli. CEG-GZL20 exhibited high antibiotic resistance and only showed sensitivity to two antibiotics, Tetracycline and Gentamicin. As E. coli is a key component of the gut microbiota, responsible for digestion, nutrient absorption, and immune health, diseases and mortality caused by E. coli have significant implications for animal husbandry and human health.
ARTICLE | doi:10.20944/preprints202307.0935.v1
Subject: Biology And Life Sciences, Aquatic Science Keywords: antibiotic-resistant; doxycycline; microorganisms; ecosystems
Online: 14 July 2023 (07:57:19 CEST)
Antibiotics are released into the environment either directly in an unchanged form or in a partially metabolized form. The discharge is usually through untreated waste or industrial treatment effluents. The potential concern is the uptake of these antibiotics by crops irrigated by treated wastewater. This study collected wastewater from eight points at the Pagla, Kadamtali, Dhaka treatment plant. Here we consider three crucial antibiotics, Doxycycline, Ciprofloxacin, and Tetracycline, used mainly during the last two years of the pandemic. A PDA detector was used in high-performance liquid chromatography (HPLC) analysis to determine the raw and processed effluent antibiotics. The most frequently seen antibiotics in natural wastewater were Doxycycline and Ciprofloxacin, with the highest concentration of 0.23µgL-1and 0.20 µgL-1(raw water), respectively. Tetracycline was not detected in natural water. Contrarily, Doxycycline was discovered in the Pagla plant's completed water and had the highest concentration (0.12 gL-1), whereas Ciprofloxacin and Tetracycline were not found in the dead water. The findings of this study showed that Doxycycline was still present in both the raw and processed effluent. Both natural and finished wastewater was subjected to a microbial-resistant test in the presence of all three antibiotics. The results revealed that the samples detected both heterotrophic bacteria and total coliform. The viable aerobic heterotrophic bacteria ranged between 5.421 and 4.754 log cfu/ml. Total bacteria load gradually decreased in the finished wastewater.
ARTICLE | doi:10.20944/preprints202305.2193.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Tuberculosis; Drug Resistant; Management; Awareness
Online: 31 May 2023 (08:00:05 CEST)
Background: Although Tuberculosis (TB) is one of the oldest diseases known to mankind, many practitioners are still unaware of various aspects of management of TB including drug resistant TB. To be able to make an impact on the disease burden we need to understand the knowledge, attitude and practices (KAP) of practitioners, both in government and private sector, towards TB case management. Methodology: A random cross-sectional survey of 99 respondents to assess the KAP towards TB case management using a digital semi-structured questionnaire which was pre-tested and administered to allopathic practitioners from across States in North and Central India. Results: 77% responders were government doctors and 23% were private practitioners. Chest physicians accounted for 61% of the responders. 26% of government and 78% of private doctors relied on sources which are difficult to validate for their knowledge on drug resistant TB management. There were large variations seen in knowledge on modes of transmission, standard precautions, extent of drug resistant TB, diagnostics as well as treatment regimen for drug resistant TB. Conclusion: The knowledge of both sector doctors especially amongst private practitioners with respect to the awareness of extent, diagnosis, and treatment and infection control measures for drug resistant TB is suboptimal which translates to poor diagnostic, therapeutic and infection control choices amongst private practitioners. If India has to achieve the targets for TB Elimination by 2025, serious work needs to be done to upgrade the knowledge of the private sector doctors on drug resistant tuberculosis. The Ministry of Health and Family Welfare, GoI needs to have regular educational programs for the private practitioners coupled with awareness campaigns and frequent surveys to assess the knowledge, attitude and practices being followed in the private sector for TB management including drug resistant TB.
REVIEW | doi:10.20944/preprints202111.0358.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: multidrug-resistant (MDR); Nanotechnology; Antimicrobial
Online: 19 November 2021 (14:31:33 CET)
The global spread of multidrug-resistant (MDR) microbial infections is currently one of the most severe risks to global public health, with 10 million fatalities expected by 2050 unless action is taken. Nanotechnology has revolutionized science and medicine. The reliance on nanotechnology is growing. Nanoparticles have distinct properties that improve biological, chemical, and physical properties studied for various uses. A significant area of attention in the synthesis of nanoscale modulators is the utilization of crude formulations, retro-synthesized, and pure chemicals, mainly from herbal sources, with fewer adverse effects. Green chemistry has devised a tangential technique for synthesizing metals and metal oxides to produce nanoparticles. Plant extracts (leaves, stems, and shoots) and microorganisms (bacteria, fungus, and yeast) are used as reducing intermediates to make nanoparticles. Studies in microbiology have shown that nanoparticles kill bacteria, fungi, viruses, and protozoa. These green nanoparticles contain antibacterial, antifungal, and anti-inflammatory effects. Most nanoparticles have high antibacterial properties, indicating they may be used to combat diseases and biological contaminants. These nanoparticles have antibacterial action against pathogenic microorganisms that cause serious illnesses, including multidrug-resistant pathogens. The current research will pave the way for future applications and improved methods for producing nanoparticles, paving the way for an innovative route in nano-life sciences with widespread recognition.
ARTICLE | doi:10.20944/preprints201910.0119.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: pasta; glycemic index; resistant starch
Online: 10 October 2019 (15:02:17 CEST)
The aim of this study was to establish the blood glucose response to different cooking methods of pasta. Participants consumed three identical meals in a random order that were freshly cooked (hot), cooled and reheated. Blood glucose concentrations were assessed before, and every 15 minutes after ingestion of each meal for 120 minutes. There was a significant interaction between temperature and time (F(8.46-372.34) = 2.75, p = 0.005), with the reheated (90 minutes) condition returning to baseline faster than both cold (120 minutes) and hot conditions. Blood glucose AUC was significantly lower in the reheated (703 ± 56 mmol L-1 min-1) compared with the hot condition (735 ± 77 mmol L-1 min-1, t(92) = -3.36, pbonferroni = 0.003), with no significant difference with the cold condition (722 ± 62 mmol L-1 min-1). To our knowledge, the current study is the first to show that reheating pasta causes changes in post-prandial glucose response, with a quicker return to fasting levels in both the reheated and cooled conditions compared with the hot condition. The mechanisms behind the changes in post-prandial blood glucose seen in this study are most likely related to changes in starch structure and how these changes influence glycaemic response.
ARTICLE | doi:10.20944/preprints202310.0546.v2
Subject: Public Health And Health Services, Public Health And Healthcare Keywords: Candida auris; C. auris; Candida; Candidemia; Multi-drug resistant organism; MDRO; Emerging pathogens; Resistant pathogens
Online: 30 November 2023 (12:04:07 CET)
Background Candida auris is an emerging multidrug-resistant fungal pathogen that represents a serious threat to healthcare settings currently. Objective: Its objective was to determine the prevalence of C. auris in the hospital since its initial detection in late 2019. Methods: Using an adapted risk assessment tool, we reviewed the charts. and medical files of all suspected? and confirmed cases of C. auris cases reported at King Khalid University Hospital, Riyadh between November 2019 and December 2022. Anonymized data were retrieved in a pre-established datasheet and analyzed to determine the epidemiological characteristics of C. auris infection in our facility. We established our initial prevalence by age, gender, risk factors, and according to sampling source. Results: Of the 53 confirmed cases positive for C. auris during the study period, 33 (62%) were males. Their ages ranged between 15 and 98; most positive cases occurred in 50 and above. Only one of the confirmed cases was hospital-acquired. All patients had at least one risk factor, and Urine samples yielded the greatest number of positive cases while admission to healthcare facilities constituted the highest risk in our study. Conclusion: Establishing a local prevalence could serve as our baseline/benchmark to compare with regional and international benchmarks.
ARTICLE | doi:10.20944/preprints202309.0663.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Drug-resistant epilepsy; Hemispherotomy; Surgical procedure.
Online: 11 September 2023 (10:15:13 CEST)
(1) Background: Hemispherotomy is the generally accepted treatment for hemispheric drug resistant epilepsy (DRE). Lateral or vertical approaches are performed according to the surgeon's preference. Multiples technical variations have been proposed since Delalande first described his vertical technique. We propose a sub-insular variation of the vertical parasagittal hemispherotomy (VPH) and describe our case series of patients operated on with this procedure. (2) Methods: a continuous series of patients operated on by the senior author (CR) with the modified sub-insular VPH was retrospectively analyzed. We report the demographic pre-operative characteristics, epilepsy and functional outcome as well as the surgical complications.(3) Results: Twenty-five patients were operated on between August 2008 and August 2023, twenty-three of them have at least a 3-month follow-up. On this last group 86,3% of patients were seizure-free. Only two patients developed post-operative hydrocephalus (8.7%), all patients with autonomous preoperative walk and 86,3% of the total series were able to walk without assistance (86.3%) and perform adapted social activities at last follow-up.(4) Conclusion: The modified vertical parasagittal sub-insular hemispherotomy is a successful surgical technique for hemispheric DRE with seizure freedom rates similar to the biggest series reported in the literature. Compared to other series, patients operated with our modified technique had a lower rate of postoperative hydrocephalus and excellent long-term motor and cognitive outcome.
ARTICLE | doi:10.20944/preprints202308.1353.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: pIgR; polymorphism; disease-resistant; growth; chicken.
Online: 21 August 2023 (03:11:16 CEST)
Polymeric immunoglobulin receptor (pIgR) plays an important role in mediating mucosal defenses, but the association between its single nucleotide polymorphisms (SNPs) and traits (such as growth and disease-resistant) in birds is scarcely known. In this research, we aimed to detect the single nucleotide polymorphisms of the pIgR gene in the chicken F2 resource population and discern the possible associations between pIgR SNPs and chicken growth, disease-resistant, respectively. Six-SNPs (3, 9, 15, 16, 19, and 21) in chicken (Gallus gallus) were significantly associated with disease-resistant in the pIgR gene (P < 0.05). The major allele genotype with SNP 9 and SNP 19 occurred more frequently with high Newcastle Disease Virus (NDV) antibody rates; the major allele genotype with the SNP 3 was predominant in those with significantly lower NDV antibody rates (P < 0.05); heterozygous with the SNP 15 and SNP 21 occurred more frequently with high avian leukemia virus (ALV) antibody rates; the TT genotypes with the SNP 16 was predominant in those with low infectious bursal disease (IBD) antibody rates (P < 0.05). Besides, SNP 12 showed significant associations with body weights (BW) and shank lengths (SL) (P < 0.05). Genotyping revealed that the C allele occurred more frequently in breeds with high growth rates and the T allele was predominant in those with low growth rates at 8, 10, and 12w of age (P < 0.05). This polymorphic site may serve as a useful target for the marker assisted selection of growth and disease-resistant traits in chicken.
ARTICLE | doi:10.20944/preprints202304.0083.v3
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: drug-resistant TB; heteroresistance; mutations; spoligotyping
Online: 9 June 2023 (15:36:21 CEST)
Drug-resistant tuberculosis (DR-TB) is still a major public health concern in South Africa. Mutations in M. tuberculosis can cause varying levels of phenotypic resistance to anti-TB medications. There have been no prior studies on gene mutations and the genotyping of DR-TB in the rural Eastern Cape Province; hence we aimed to identify DR-TB mutations, genetic diversity and allocated lineages among patients in this area. Using Xpert® MTB/RIF, we assessed the rifampin-resistance of sputum samples collected from 1157 patients suspected of having tuberculosis. GenoType MTBDR plus VER 2.0 was used for the detection of mutations causing resistance to anti-TB medications. The next step was to spotlight type 441 isolates. The most prevalent rifampin resistance-conferring mutations were in rpoB codon S531L, in INH-resistant strains, katG gene at codon S315TB and the inhA gene at codon C-15TB had highest mutations; 54.5% and 24.7%, respectively. In addition, 24.6% of strains showed mutations in both the rpoB and inhA genes, while 69.9% of strains showed mutations in both the katG and rpoB genes. Heteroresistance was seen in 17.9% of all cases in the study. According to spoligotyping analysis, Beijing families predominated. Investigating the evolutionary lineages of M. tuberculosis isolates can be done using the information provided by the study's diversity of mutations. In locations where these mutations have been discovered, decision-making regarding standardization of treatment regimens or individualized treatment may be aided by the detection frequency of rpoB, katG, and inhA mutations in various study areas.
REVIEW | doi:10.20944/preprints202209.0037.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Multidrug-resistant Acinetobacter baumannii; Phage therapy
Online: 2 September 2022 (09:51:24 CEST)
Acinetobacter baumannii is a multidrug-resistant and invasive pathogen associated with the etiopathology of both an increasing number of nosocomial infections and of relevance to poultry production systems. Multidrug-resistant Acinetobacter baumannii has been reported in connection to severe challenges to clinical treatment, mostly due to an increase rate of resistance to carbapenems. Amid the possible strategies aiming to reduce the insurgence of antimicrobial resistance, phage therapy has gained particular importance for the treatment of bacterial infections. This review summarises the different phage-therapy approaches currently in use for multiple-drug resistant Acinetobacter baumannii, including single phage therapy, phage cocktails, phage -antibiotic combination therapy, phage coding Acinetobacter baumannii and the novel phage enzyme treatment. Although phage therapy represents a potential treatment solution for multidrug-resistant Acinetobacter baumannii, further research is needed to unravel some unanswered questions especially in regard to its in vivo applications, before possible routine clinical use.
ARTICLE | doi:10.20944/preprints201902.0132.v1
Subject: Engineering, Mechanical Engineering Keywords: beetle elytra; snap-through; puncture-resistant
Online: 14 February 2019 (10:57:06 CET)
Beetles are by far one of the most successful and diverse insect species. A part of this success is attributed to their elytra which provide various functions such as protection to their bodies from mechanical forces and the harmful environmental factors. In this study, Stag beetle (Lucanus cervus) elytra were first examined for their overall flexural properties and were observed to have a localized shape retaining snap-through mechanism which could play a crucial role in energy absorption, e.g. during battles and falls from heights. The snap-through mechanism was validated using theoretical calculations and also finite element simulations. Elytra were also characterized to examine their puncture and wear resistance. Our results show that elytra resisted puncture up to a force of 1.8±0.4 N and have puncture resistance compared to that of commercially available puncture resistant gloves. The measured values of modulus and hardness of elytra exocuticle were 10.3±0.8 GPa and 0.7±0.1 GPa. Using the hardness to modulus ratio as an indicator of wear resistance, the estimated value was observed to be in the range of wear resistant biological materials. Thus, our study demonstrates different mechanical properties of the stag beetle elytra which can be explored to design shape retaining bio-inspired composites with enhanced puncture and wear resistance.
ARTICLE | doi:10.20944/preprints202310.1916.v1
Subject: Medicine And Pharmacology, Pulmonary And Respiratory Medicine Keywords: Mycobacterium tuberculosis; Rifampicin; drug resistant; sensitivity; specificity
Online: 30 October 2023 (12:19:14 CET)
Xpert MTB/RIF is rapid molecular diagnostic tool capable of simultaneously detecting Mycobacterium tuberculosis and rifampicin resistance. This study aimed to access the diagnostic precision of Xpert MTB/RIF assay to detect pulmonary and extra-pulmonary tuberculosis and to evaluate the performance for the detection of rifampicin resistance. Of 37695 samples, 7156(18.98%) were tuberculosis positive, 509(7.11%) were rifampicin-resistant. The sensitivity, specificity, PPV, NPV, Diseases prevalence and accuracy of Xpert MTB/RIF assay for PTB were 99.87% (95%CI:99.75-99.94), 99.92%(95%CI:99.88-99.95), 99.71%(95%CI:99.54-99.82),99.97%(95%CI:99.93-99.98),21.38% (95%CI:20.92-21.86),and 99.91%(95%CI:99.87-99.94), respectively. For EPTB, the sensitivity, specificity, PPV, NPV, Diseases prevalence and accuracy of Xpert MTB/RIF assay accounted for 99.45% (95%CI:98.73-99.82),99.84%(95%CI:99.73-99.92),98.70%(95%CI:97.73-99.25),99.93% (95%CI:99.84-99.97),10.64%(95%CI:9.99-11.31),and 99.80%(95%CI:99.68-99.88), respectively. Despite its high sensitivity for detecting tuberculosis and rifampicin resistance, Xpert MTB/RIF had contradictory results for 20.5% of cases among patients with negative smear results and 54.9% of cases among patients with a high risk of Multidrug-resistant tuberculosis. Of 47 fluoroquinolone-resistant, 16.56% (26/157) of Multidrug-resistant tuberculosis isolates and 4.02% (20/498) isoniazid-resistant are fluoroquinolone-resistant, a characteristic distribution leading to about 17.2% of fluoroquinolone resistance events and relevant marker gyr-A mutations in MDR tuberculosis isolates. Further, our study indicated that increased fluoroquinolone resistance among Rifampicin-resistant and isoniazid-resistant tuberculosis endangers the success of newly endorsed MDR-TB regimens.
INTERESTING IMAGES | doi:10.20944/preprints202309.1918.v1
Subject: Medicine And Pharmacology, Pulmonary And Respiratory Medicine Keywords: multidrug-resistant tuberculosis; genetic mutations; clinical cases.
Online: 28 September 2023 (08:02:58 CEST)
The emergence of M. tuberculosis strains resistant to Isoniazid (INH) and Rifampicin (RIF), the two most potent drugs of first-line anti-TB therapy is termed multidrug drug-resistant TB (MDR-TB). Multidrug-resistant tuberculosis has been a serious medical and epidemic problem all over the world. We present here a series of clinical cases consist of two patients diagnosed with isoniazid resistant tuberculosis. Histopathological examination supports the diagnosis of tuberculous granulomas. And the pathology molecular examination revealed the presence of Isoniazid-resistant Mycobacterium tuberculosis1,2 via the following mutation c.947G>A; p.Gly316Asp. Isoniazid-resistance is associated with mutations in the furA-katG and fabG1-inhA operons, as well as mutations in the ahpC gene. 64% of the isoniazid-resistance phenotypes were associated with the katG315 mutation worldwide. The second most common mutation is inhA-15, and it has been reported in 19% of the Isoniazid-resistant isolates. The significant association between the two mutations, inhA c-15 and katG 315 respectively, and the high-level resistance is of interest in the interpretation of current and future molecular diagnostic testing, as an early prediction of the level of Isoniazid-resistance is essential to decide the benefit of high-dose Isoniazid use.
ARTICLE | doi:10.20944/preprints202306.0831.v1
Subject: Engineering, Mechanical Engineering Keywords: durability; self-cleaning; superhydrophobicity; superoleophobicity; wear-resistant
Online: 12 June 2023 (11:51:38 CEST)
Inspired by nature's examples such as lotus leaves and insect wings, superhydrophobic surfaces have been extensively studied and engineered. However, achieving superoleophobic surfaces, which repel oils, has proven to be more challenging due to the oils' lower surface tension than water. This article presents a novel, cost-effective technique for fabricating superoleophobic surfaces with enhanced durability. We demonstrate the effectiveness of this technique by using Perfluorooctyltriethoxysilane (PFOTES) and silicon dioxide nanoparticles on stainless steel mesh substrate. The resulting surfaces exhibit remarkable superoleophobic properties by incorporating re-entrant structures, low surface energy, and high surface roughness, making them ideal for oil-repellency applications.
ARTICLE | doi:10.20944/preprints202304.0794.v1
Subject: Biology And Life Sciences, Aquatic Science Keywords: penaeid shrimp; hemocyte; disease-resistant; Vibrio parahaemolyticus
Online: 23 April 2023 (08:27:29 CEST)
Vibrio parahaemolyticus carrying a plasmid encoding toxins PirA and PirB is one of the causative agents leading to the severe disease of acute hepatopancreatic necrosis disease (AHPND) in shrimp aquaculture. However, there is a lack of deep understanding of the host resistant characteristics against V. parahaemolyticus infection. Here, we performed comparative transcriptome analysis on the expression profiles at the background level of hemocytes from shrimp with different resistant abilities against V. parahaemolyticus infection in two independent populations. Principal component analysis and sample clustering results showed that samples from the same population had a closer relationship than that from shrimp with similar disease-resistant abilities. Differentially expressed genes (DEGs) analysis revealed that the number of DEGs between two populations was much more than that between V. parahaemolyticus¬-resistant and susceptible shrimp. A total of 31 DEGs and 5 DEGs were identified from the comparison between V. parahaemolyticus¬-resistant and susceptible shrimp from population 1 and 2, respectively. There was no DEGs overlap between two comparisons. DEGs from population 1 were mainly cytoskeleton related genes, metabolic related genes, and immune related genes. DEGs from population 2 included tubulin alpha-3, dihydropyrimidinase-like gene, diacylglycerol kinase 1, prohibitin and iroquois-class homeodomain protein IRX-2-like. The data suggest that shrimp from different populations might adopt distinct disease-resistant mechanisms, which provided new insights into understanding disease-resistant mechanisms at population level against pathogen infection. A new strategy for screening disease resistant genes and disease resistant breeding was proposed based on the present study.
ARTICLE | doi:10.20944/preprints202209.0384.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: prebiotics; resistant starch; inulin; polydextrose; farinography; extensography
Online: 26 September 2022 (08:32:33 CEST)
The addition of prebiotics is one of the most important ways to improve the techno-functional properties of bread. In this study, the effects of resistant starch, polydextrose, and inulin on the wheat flour, dough, and bread properties were investigated. In farinography results, resistant starch significantly increased the development time (2:18) with a boosting effect, but polydextrose (1:48) and inulin (1:36) weakened the dough (P <0.05). Inulin, polydextrose, and resistant starch had the most effect on reducing water absorption (40, 43.2, and 48.9) respectively (P <0.05). According to extensography data, inulin had the best result in baking compared to other polysaccharides. In terms of baked breads, samples containing resistant starch had high moisture that could be due to starch gelatinization and moisture-retaining, which delays the staling process of bread. Inulin, polydextrose, and resistant starch prebiotic ingredients affected dough rheological properties and bread quality, and organoleptic characteristics, however, resistant starch was the best.
REVIEW | doi:10.20944/preprints202006.0173.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: pandrug-resistant; treatment; carbapanemase; Acinetobacter; Klebsiella; Pseudomonas
Online: 14 June 2020 (13:19:32 CEST)
The management of carbapenem-resistant infections is often based on colistin, tigecycline, aminoglycosides and their combinations. However, in a recent systematic review we found that Gram-negative bacteria (GNB) co-resistant to carbapanems, aminoglycosides, colistin and tigecycline (CACT-resistant) are increasingly being reported worldwide. Clinical data to guide the treatment of CACT-resistant GNB are scarce and based exclusively on few case reports and small case series but seem to indicate that appropriate (in vitro active) antimicrobial regimens, including newer antibiotics and synergistic combinations, may be associated with lower mortality. In this review we consolidate the available literature to inform clinicians dealing with CACT-resistant GNB about treatment options by considering the mechanisms of resistance to carbapenems. In combination with rapid diagnostic methods that allow fast detection of carbapenemase production, the approach proposed in this review may guide a timely and targeted treatment of patients with infections by CACT-resistant GNB. Specifically, we focus on the three most problematic species, namely Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. Several treatment options are currently available for CACT-resistant K. pneumonia. Newer β-lactam-β-lactamase combinations, including the combination of ceftazidime/avibactam with aztreonam against metallo-β-lactamase-producing isolates, appear to be more effective compared to combinations of older agents. Options for P. aeruginosa (especially metallo-β-lactamase-producing strains) and A. baumannii remain limited. Synergistic combination of older agents (e.g. colistin- or fosfomycin-based synergistic combinations) may represent a last resort option but their use against CACT-resistant GNB requires further study.
ARTICLE | doi:10.20944/preprints202310.0814.v1
Subject: Computer Science And Mathematics, Mathematical And Computational Biology Keywords: Agent-based modelling; antimicrobial-resistant gonorrhea; surveillance systems
Online: 12 October 2023 (11:24:24 CEST)
We aim to evaluate efficiency of two American surveillance systems for monitoring the spread of antimicrobial-resistant (AMR) gonorrhea among men who have sex with men (MSM) using the novel continuous-time agent-based model of gonorrhea transmission. The model was developed using the simulation modelling tool AnyLogic and accounts for susceptible and resistant strains of N. gonorrhoeae, symptomatic and asymptomatic infection and various routes of transmission between different anatomical sites. The model was calibrated using a Bayesian calibration approach. The surveillance systems are the Gonococcal Isolate Surveillance Project (GISP) and the enhanced Gonococcal Isolate Surveillance Project (eGISP). We calculated accuracy, sensitivity, specificity and estimation error for each surveillance system based on the number of isolates submitted in 2018. We also varied that number to see its effect on the outcomes. Our results show that the accuracy of eGISP was between 66% and 92%, while GISP demonstrates low accuracy between 44% and 48%. We also determined that increasing the number of isolates results in improved performance for eGISP, while GISP is not particularly sensitive to it.
REVIEW | doi:10.20944/preprints202307.1875.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: polysaccharides; flame retardants; sustainability; aerogels; fire-resistant composites
Online: 27 July 2023 (08:31:43 CEST)
Fire safety is a critical concern in various industries necessitating the development of sustainable and effective fire-resistant materials. Sustainable fire-resistant polysaccharide-based composite aerogels are regarded as innovative solutions in fire safety applications, and as such, research in this field has increased consistently over the past few years. Despite the plethora of literature on this important subject, only a few studies have attempted to map the global research of sustainable fire-resistant polysaccharide-based composite aerogels to identify the geospatial collaborative network and trend of research. This study utilizes a scientometric review of global trends in sustainable fire-resistant polysaccharide-based composite aerogels research between 2003–2023 by VOSviewer and biblioshiny to analyze co-author, co-word, co-citation, clusters, and geospatial map. A total of 234 bibliographic records from the Scopus database were analyzed to generate the study's research power networks and geospatial map. The most significant contributions in sustainable fire-resistant polysaccharide-based composite aerogels comes from China, the United States, Australia, Canada, and India with records of 194, 20, 11, 9, and 8 respectively. The top five sources for articles in this area of research include ACS Applied Materials and Interfaces, Chemical Engineering Journal, Composite Engineering, ACS Sustainable Chemistry and Engineering, and Carbohydrate Polymers. The application of sustainable fire-resistant polysaccharide-based composite aerogels spans the engineering and construction fields. The versatility in the fabrication and customization allows for seamless integration into diverse applications. The article concludes by emphasizing the significance of sustainable fire-resistant polysaccharide-based composite aerogels as a promising advancement in fire safety technology, combining sustainability, fire resistance, versatility, and mechanical strength to address critical challenges in the field. This study provides readers with an extensive understanding of the salient research themes, trends, and patterns of sustainable fire-resistant polysaccharide-based composite aerogel research worldwide.
ARTICLE | doi:10.20944/preprints202307.0998.v1
Subject: Medicine And Pharmacology, Dermatology Keywords: acne vulgaris; insulin resistance; HOMA-IR; resistant acne
Online: 14 July 2023 (11:12:45 CEST)
Acne vulgaris has multifactorial pathogenesis which may include insulin resistance. To investigate whether insulin resistance is a causative factor in acne vulgaris development, this study and a systematic review were conducted. 41 acne vulgaris patients and 47 healthy BMI-matched controls were involved. Glucose and insulin fasting serum levels were obtained, HOMA-IR was calculated, insulin resistance was diagnosed in cases with HOMA-IR value over 2.1. The mean±SD values for glucose fasting serum level were as follows: 94.88±7.731 [mg/dl] in study group and 79.51±7.175 [mg/dl] in controls (p<0.001). The mean±SD insulin fasting serum levels were 14.47±6.394 [µIU/mL and 11.83±4.309 [µIU/mL](p=0.059), respectively. The HOMA-IR mean±SD value calculated for the study group was 3.4±1.49 and in the control group 2.34±0.909 (p<0.001).Out of 41 patients 32 were diagnosed with insulin resistance (78%) and 26 of the 47 controls 26 were diagnosed with IR (55%) (p=0.026). Insulin resistance diagnosis was statistically more common among the acne patients compared to the controls. In the articles reviewed insulin resistance was found to be more frequent in acne vulgaris patients. Both our study and the papers analysed indicate that insulin resistance might be an independent factor in acne vulgaris development and should be considered when diagnosing and treating acne.
ARTICLE | doi:10.20944/preprints202305.1597.v1
Subject: Engineering, Other Keywords: Lightweight; Fire Resistant Board, Intumescent, Passive Fire Protection
Online: 23 May 2023 (07:37:19 CEST)
Using lightweight fire-rated board (LFRB) presents cost-effective opportunities for various passive fire protection measures. The aim of the project is to develop a LFRB with enhanced fire resistance, acoustic properties, and mechanical properties. These properties were determined using the Bunsen burner, furnace, energy dispersive X-Ray, impedance tube instrument, and Instron universal testing machine. To fabricate the LFRBs, vermiculite and perlite were blended with flame-retardant bind-ers, and four types of LFRBs were produced. A fire test was conducted to compare the fire-resistance performance of the LFRBs with a commercially available flame retardant board. The B2 prototype showed exceptional fire-resistant properties, with a temperature reduction of up to 73.0 °C as compared to the commercially available fire-rated magnesium board. Incorporating nano chicken eggshell into the specially formulated flame-retardant binder preserved the LFRBs’ structural integrity, enabling them to withstand fire for up to 120 minutes with an equilibrium temperature of 92.6 °C. This approach also provided an absorption coefficient of α = 2.0, a high flexural strength of 3.54 MPa, and effective flame retardancy properties with a low oxygen/carbon ratio of 2.60. These results make the LFRBs valuable for passive fire protection applications in the construction and building materials industry.
ARTICLE | doi:10.20944/preprints202011.0670.v1
Subject: Engineering, Automotive Engineering Keywords: turbine jet engine; material tests; ember-resistant alloys
Online: 26 November 2020 (11:20:45 CET)
The structural and strength analysis of the material used to construct such an important engine element as the turbine is of great significance, both at the design stage as well as during tests and expertises related to emergency situations. Bearing in mind the conditions above mentioned, the paper presents the results of research on the chemical composition, morphology and phased structure of the metallic construction material used to produce the blades of the high and low pressure turbine of the RD-33 jet engine, which is the propulsion unit of the MiG-29 aircraft. The data obtained as a result of the material tests of the blades allowed, on the basis of the analysis of chemical composition and phased structure, to determine the grade of the alloy used to construct the tested elements of the jet engine turbine. The structural stability of the material was found to be lower in comparison with engine operating conditions, which manifested itself as a clear decrease in the resistance properties of the blade material. The results obtained can be used as a basis for analyzing the life span of an object or a selection of material replacements, which enable to produce the analyzed engine element.
ARTICLE | doi:10.20944/preprints202003.0060.v1
Subject: Medicine And Pharmacology, Dietetics And Nutrition Keywords: Alcaligenes faecalis; Diabetic foot ulcer; extensive-drug resistant
Online: 4 March 2020 (10:34:23 CET)
Background: Diabetic foot ulcers are an increasingly common complex problem and are associated with a very considerable health care burden. Diabetic foot ulcer with Alcaligenes faecalis infection is rarely reported in the literature. We report a case series of diabetic foot ulcer with Alcaligenes faecalis infection treated at our facility. Methods: We conducted a retrospective analysis of all patients with diabetic foot ulcer with Alcaligenes faecalis infection seen from January 2014 to April 2019. We analyzed the clinical characteristics, ulcer lesion classification, comorbidities, prior intravenous antibiotic use within three months, wound culture, antibiotics sensitivity test, and clinical outcomes of these patients. Results: Eight cases of diabetic foot ulcer with Alcaligenes faecalis infection were seen in five males and three females. The mean age was 54.6 years. All patients had other comorbidities, and all ulcer lesions were of chronic duration ( more than 14 days ). All wound cultures revealed polymicrobial infection, with two cases of diabetic foot with extensive-drug resistant Alcaligenes faecalis infection found in 2019. All patients needed intravenous antibiotic therapy and surgical interventions for the chronic ulcer lesion. The wound failed to heal in three patients. Conclusions: All diabetic foot ulcers with Alcaligenes faecalis infection were of chronic duration ( more than 14 days ) and had polymicrobial infection. Extensive-drug resistant Alcaligenes faecalis emerged in 2019. Definitive antibiotic therapy is necessary for all infected wounds and should be based on both the culture results and susceptibility data. All patients will need appropriate wound care, and most will need rapid surgical intervention for an optimal outcome.
ARTICLE | doi:10.20944/preprints201905.0137.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: trimethoprim-resistant dihydrofolatereductases, antimicrobial resistance, biocuration, nomenclature, phylogeny
Online: 10 May 2019 (15:14:41 CEST)
With the increasing use of genome sequencing as a surveillance tool for molecular epidemiology of antimicrobial resistance (AMR), databases and clear nomenclature for AMR gene families are critical. Due to the convoluted nomenclatural history of the integron-associated trimethoprim-resistant dihydrofolatereductase (dfr) gene family, we decided to conduct a literature review, comparative sequence analysis, and phylogenetic investigation of the dfr family, the results of which are presented here and available at the Comprehensive Antibiotic Resistance Database (CARD). Overall, literature review and phylogenetic analysis resolved gene name synonyms based on sequence. We recommend adoption of phylogenetic methods to help guide AMR gene naming efforts and relegation of misleading names to synonyms.
ARTICLE | doi:10.20944/preprints201808.0435.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Respiratory tract infections (RTI); antibiotic; sensitivity; resistant; bacteria
Online: 24 August 2018 (11:46:41 CEST)
1) Background: Respiratory tract infections (RTI) has been known to be a significant health concern for mortality and morbidity since many years. This study was aimed at determining the prevalence of bacterial pathogen causing upper respiratory tract (URTIs) and the susceptibility patterns to frequently used antibiotics among patients attending Abusetta hospital in Tripoli district; 2) Methods: A total of 1,110 throat swabs were collected between Jan, 2011 to December, 2014 and inoculated onto Blood agar, MacCkonkey agar and Chocolate agar then incubated at 37 oC for 24 hours. Bacterial pathogens were determined by bacteriological culture methods and antibiotic susceptibility of the isolates was identified following Clinical Laboratory Standard Institute guidelines (CLSI); 3) Results: Of the 1,110 respiratory samples tested, 71.1% (n = 789) of specimens were positive cultures with the dominant bacterial pathogens being streptococcus pneumonia 43.3% (n = 342), followed by pseudomonas aeruginosa 22.8% (n = 180), staphylococcus aurous 13.8% (n = 109), Escherichia Coli 6.9% (n = 55), Enterobacter spp 6.2% (n = 49), Citrobacter 4.5% (n = 36), and Klebsiella 2.2% (n = 18). Most isolates exhibited resistance against the commonly used antibiotics and to at least one antibiotic; and 4) Conclusions: The level of antibiotic resistance in this study is alarming and brings to light the timely and suitable diagnosis of the common bacteria causes of URTIs and proper antibiotic administration based on susceptibility test.
ARTICLE | doi:10.20944/preprints202308.1895.v1
Subject: Public Health And Healthcare, Primary Health Care Keywords: keyword multidrug-resistant tuberculosis; gene mutations; heteroresistance; Beijing variants
Online: 29 August 2023 (03:33:51 CEST)
Multidrug-resistant tuberculosis emerged as a serious challenge to tuberculosis management and control. In the Eastern Cape, the Beijing variants are prevalent and a driving force of multidrug-resistant tuberculosis; hence, we investigated the distribution of gene mutations in Beijing strains compared to non-Beijing strains. Multidrug-resistant tuberculosis and heteroresistant isolates were identified in 412 sputum cultures by drug susceptibility testing. The isolates were analyzed for mutations in three genes associated with resistance to antituberculosis first-line drugs: katG and inhA promoters for isoniazid and rpoB for rifampicin. All isolates were genotyped by spoligotyping. There were more males than females and a more economically active age group in the study. The most prevalent mutations in rpoB resistance were in S531L, katG in S315Tb, and inhA in c-15tb. Heteroresistance was found in 18 isolates. Beijing variants were predominant. Most of the heteroresistant isolates were INH, with heteroresistance occurring more in the inhA gene mutation region c-15tb. Beijing and LAM variants were found more frequently in INH heteroresistant isolates. Mutations in katG S315Tb and rpoB S531L were higher in Beijing variants. The Beijing family is a major contributor to the epidemiological picture and accounts for most of the multidrug-resistant tuberculosis in the study area.
ARTICLE | doi:10.20944/preprints202211.0314.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antimicrobial peptides; Synthetic peptides; multidrug resistant bacteria; proteomic analysis
Online: 16 November 2022 (13:15:11 CET)
Klebsiella pneumoniae is a multidrug-resistant opportunistic human pathogen related to various infections. As such, synthetic peptides have emerged as potential alternative molecules. Mo-CBP3-PepI has presented great activity against K. pneumoniae by presenting an MIC50 at a very low concentration (31.25 µg mL-1). Here, fluorescence microscopy and proteomic analysis revealed the alteration in cell membrane permeability, ROS overproduction, and protein profile of K. pneumoniae cells treated with Mo-CBP3-PepI. Mo-CBP3-PepI led to ROS overaccumulation and membrane pore formation in K. pneumoniae cells. Furthermore, the proteomic analysis highlighted changes in essential metabolic pathways. For example, after treatment of K. pneumoniae cells with Mo-CBP3-PepI, it was seen a reduction in the abundance of protein related to DNA and protein metabolism, cytoskeleton and cell wall organization, redox metabolism, regulation factors, ribosomal proteins, and resistance to antibiotics. These reductions lead to the inhibition of DNA repair, inhibition of cell wall turnover, protein turnover, and ROS accumulation leading to cell death. Our findings indicated that Mo-CBP3-PepI might have mechanisms of action against K. pneumoniae cells, mitigating the development of resistance and thus being a potent molecule to be employed in producing new drugs against K. pneumoniae infections.
CONCEPT PAPER | doi:10.20944/preprints202004.0358.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: MDR typhoid; metal resistant genes; water toxicity; gut microbiome
Online: 20 April 2020 (02:27:07 CEST)
AMR and drug void have caused huge panic today with few thousand death per year. MDR Typhoid was a serious old disease and caused serious health hazard in humen and animals demanding an update on molecular biology of the status on transferable genetic elements. R-plasmids combined in F’-plasmid and the new MDR conjugative plasmids were shown abundant in Sanmonella ranging 70-440kb with similarities. BlaTEM, blaCTX-M, blaOXA, blaNDM mdr genes were abundant in >50 plasmids analyzed and metal resistant gene clusters are predominant in most large plasmids. Among the acetyltransferase all catA1, aacA1 and aac-1b-cr genes were located. Abundant streptomycin phosphotransferases (StrAB) and rarely colistin resistant Mcr-5/9 phosphoethanolamine–lipid A transferase were detected. Altered isomeric dihydropterote synthases (Sul1/2/3) were present giving sulfamethoxazole resistance and dhfr gene frequently associated giving trimethoprim resistance. Metal resistant gene clusters like SilABC (CusABC), PcoAB, RcnA, terABC, and merABCXT etc were found in many Salmonella enterica plasmids. Toxin genes like HipA and virulence genes like spvABD were located in few plasmids increasing virulence and pathogenesis. Drug efflux genes tetA or tetB and OqxB, floR, CmlA were frequent where as QepA and EamA genes were rarely seen. Thus, Salmonella metal resistant genes combined with antibiotic resistant genes has tried to overcome the both toxic antibiotics and metalions causing Typhoid AMR. Such acquisition spreads salmoniasis in the live stocks (pig, cow, chicken) where toxic soil and water dominate increasing chance of MDR typhoid in human.
ARTICLE | doi:10.20944/preprints202204.0183.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: resistant TNBC; intra-tumoral heterogeneity; breast cancer relapse; breast cancer epigenome; me-tastasis prevention; intrinsic resistance of cancer; tumor adaptability; targeting resistant cancer
Online: 20 April 2022 (04:16:31 CEST)
We previously described a model of deep intrinsic resistance of breast cancer wherein we used a function-based approach to selection of cancer cells that can survive a variety of challenges in prolonged but reversible quiescence. Our experimental results suggested that resistant cancer cells possess a variety of mechanisms, including modifications of the epigenome and transcriptome, for generating a high degree of cellular heterogeneity. In the present study, we evaluated JIB-04, a small-molecule epigenetic inhibitor initially discovered to inhibit cancer growth, to determine its ability to affect deep intrinsic resistance in our breast cancer model. We found that long pretreatment with JIB-04 sensitized resistant triple-negative inflammatory breast cancer cells and their parental cell line SUM149 to the chemotherapeutic drugs doxorubicin and paclitaxel. Resistant cancer cells derived from another inflammatory breast cancer cell line, FC-IBC02, were considerably more sensitive to JIB-04 than was the parental cell line. Investigating a mechanism of sensitization, we found that JIB-04 exposure increased the expression of PD-L1 in resistant cells, suggesting that JIB-04 may also sensitize resistant breast cancer cells to anti-PD-L1 immune therapy. Finally, these results support the usefulness of our experimental strategy for evaluating anticancer agents such as JIB-04 that may halt cancer evolution and prevent development of cancer resistance to currently used therapies.
ARTICLE | doi:10.20944/preprints202309.1954.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Fusarium tricinctum; Trichothecium roseum; chalcone; cyanide-resistant respiration; alternative oxidase
Online: 28 September 2023 (07:12:37 CEST)
Chalcones are a class of flavonoids possessing a variety of biological activities, including antimicrobial and antioxidant effects. Therefore, chalcones and their derivatives have potential use in the control of postharvest diseases. In this work, the effects of 2ʹ,4ʹ-dichloro-chalcone on the in vitro growth and in vivo pathogenicity of F. tricinctum and T. roseum were investigated. The results showed that 100 µM of 2ʹ,4ʹ-dichloro-chalcone strongly inhibited mycelial growth and conidial production of F. tricinctum (32.3%) and T. roseum (65.2%) in vitro. This treatment also significantly inhibited the expansion of potato dry rot from F. tricinctum (48.6%) and apple rot spot from T. roseum (36.2%). The incubation of F. tricinctum and T. roseum conidia with this agent for 2 h increased their cell membrane permeability by 25% and 22.5%, respectively and conidial membrane permeability by 41.7 and 65.4%, respectively. This treatment also significantly inhibited the total respiration rate and activated the cyanide-resistant respiratory pathway in both pathogens. Protein immunoblotting showed that the treatment increased alternative oxidase (AOX) levels after 4 h in F. tricinctum and T. roseum by 52.76% and 39.13%, respectively. Conclusion: 100 µM 2ʹ,4ʹ-dichloro-chalcone significantly inhibited mycelial growth and spore production in F. tricinctum and T. roseum in vitro and reduced their pathogenicity in postharvest potato and apple crops. Further analysis indicated that 2ʹ,4ʹ-dichloro-chalcone disrupted the integrity of cell membranes and the mitochondrial respiratory electron transport chain which leaded to ROS burst and oxidative stress, AOXs were induced directly or indirectly, and the cyanide resistant respiratory pathway was activated. The in vitro growth and pathogenicity of F. tricinctum and T. roseum were inhibited.
ARTICLE | doi:10.20944/preprints202307.1963.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: 4-aminoquinoline; hydrazone; antimalarial; antimalarial drug interaction; drug-resistant malaria
Online: 28 July 2023 (07:11:59 CEST)
The emergence of resistance to first-line antimalarial drugs calls for development of new therapies for drug-resistant malaria. The efficacy of quinoline-based antimalarial drugs has prompted the development of novel quinolines. A panel of 4-aminoquinoline hydrazone analogues were tested on Plasmodium falciparum strains: IC50 values after a 48-hour cycle ranged from 0.60 - 49 µM, while the 72-hour cycle ranged from 26-219 nM on the multi-drug resistant K1 strain. Time-course assays were carried out to define the activity of the lead compounds which inhibited over 50 % growth in 24 hours and 90% growth in 72 hours. Cytotoxicity assays with HepG2 cells showed IC50 values of 0.87-11.1 M, whereas in MDBK cells IC50 values ranged from 1.66-11.7 M. High selectivity indices were observed for the lead compounds screened at 72 hours on P. falciparum. Analyses of stage-specificity revealed that the ring stage of the parasite life cycle were most affected. Based on antimalarial efficacy and in vitro safety profiles, lead compound 4-(2-benzylidenehydrazinyl)-6-methoxy-2-methylquinoline 2 was progressed to drug combination studies for the detection of synergism, with a combinatory index of 0.599 at IC90 for the combination of with artemether, indicating a synergistic antimalarial activity. Compound 2 was screened on different strains of P. falciparum (3D7, Dd2) which maintained similar activity to K1, suggesting no cross-resistance between multi-drug resistance and sensitive parasite strains. In vivo analysis with 2 showed suppression of parasitaemia with P. yoelii NL treated mice (20 mg/kg and 5 mg/kg).
ARTICLE | doi:10.20944/preprints202302.0291.v1
Subject: Chemistry And Materials Science, Physical Chemistry Keywords: Garcinia mangostana L.; Rind Extract; Antibiotic-Resistant; Streptomycin; Bioconjugation; Hemocompatibility
Online: 17 February 2023 (02:27:53 CET)
Background: Combinatorial therapy- “nano antibiotics” is an emerging field in nanoscience. In this present investigation, we attempted to combine the green synthesized noble metal nanoparticle and the antibiotic Streptomycin to form bio-conjugated nanoparticles. The newly synthesized Nano antibiotics acted as the antibiotic carrier, functioned as cargo, and delivered the antibiotic. Methods: Comparative studies between the noble metal nanoparticles were attempted for the first time on the grounds of their antibacterial activity. The antibacterial activity of the three noble metal nanoparticles was assessed against Streptomycin-resistant Bacillus sp.; the results obtained proved that silver nanoparticles were a potent antibacterial agent. Still, no antibacterial activity was exerted by gold, and platinum nanoparticles were for the Streptomycin-resistant strain Bacillus sp. To our surprise, the gold and platinum fabricated/bio-conjugated nanoparticle with the antibiotic showed 100% antibacterial activity, whose antibacterial activity was zero when functioning as a nanoparticle alone. Results: The combinatorial therapy of two different clauses of drugs majorly increased antibacterial activity. It enhanced the antibiotic to overcome the resistance exhibited by the bacterial pathogen, and the possible mechanism is elucidated in the present study. Also, an attempt has been made to assess the nanotoxicity of the nano-bioconjugates on RBC and compare their hemocompatibility. The results obtained in the current investigation demonstrate the enhanced antibacterial activity of the green synthesized nanoparticles conjugated with the streptomycin; their efficacy for combinational therapy against resistance in pathogenic organisms highlights the novelty of the work and the comparative study of three different noble metals nanoparticles (Ag, Au, Pt) from single agro-waste for the first time.
ARTICLE | doi:10.20944/preprints202301.0540.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: β -Lapachone; Bactericidal; Biofilms; Resistant; Zone of inhibition; Antimicrobial activity
Online: 30 January 2023 (06:10:49 CET)
Background: Bacterial infections constantly have a large impact on public health, because of increased rates of resistance and reduced frequency of development of novel antibiotics. The utility of conventional antibiotics for treating bacterial infections has become increasingly challenging. The aim of the study was to assess the antibacterial effect of β -Lapachone, a novel synthetic compound. Methods: The antibacterial activity of the β -Lapachone compound was examined against laboratory strains by agar well diffusion method, minimal inhibitory concentration (MICs), and minimal bactericidal concentration (MBCs). Growth kinetics inhibition in presence of β -Lapachone on Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa (ATCC 27853) was assessed by MABA. Crystal violet blue assay was used for biofilm inhibition assays, biofilm eradication assay and for molecular modeling PyMOL was used. Results: β -Lapachone exhibited potent antimicrobial activity against laboratory strains of bacteria with MIC of 0.2 mM for S. saprophyticus and Staphylococcus aureus, and 0.04 mM for Staphylococcus epidermidis and Pseudomonas aeruginosa ATCC 27853. The inhibition of catalase enzyme was found to be the cause for its antibacterial activity. Molecular modeling predicted the binding of β -Lap at active site and heme binding site of catalase, KatA. The activity of some commercial antibiotics was enhanced in association with β -Lap. In addition, β -Lap inhibited the biofilm formation and eradicated the already formed and ultra-mature biofilms of aforesaid bacterial strains.
ARTICLE | doi:10.20944/preprints202110.0372.v1
Subject: Medicine And Pharmacology, Psychiatry And Mental Health Keywords: 3MDR; treatment-resistant PTSD; military; veterans; mental health; emotional regulation
Online: 26 October 2021 (09:51:46 CEST)
Multi-modal Motion-assisted Memory Desensitization and Reprocessing Therapy (3MDR), an interactive, virtual-reality assisted, exposure-based intervention for PTSD, has shown promising results for treatment-resistant Posttraumatic Stress Disorder (TR-PTSD) among military members (MMs) and Veterans in Randomized Controlled Trials. Previous research has suggested that emotional regulation (ER) and emotional dysregulation (ED) may be factors which are correlated with symptom severity and maintenance of TR-PTSD. This embedded mixed-methods pilot study (n=9) sought to explore the impact of 3MDR on ER and ED of MMs and Veterans. Difficulties in Emotional Regulation Scale (DERS-18) data was collected at baseline, prior to each session, and at 1 week, 1 month and 3 months post-intervention and analyzed using a Wilcoxon signed-ranks test. Qualitative data collected from sessions, debriefs, and follow-up interviews were transcribed and descriptively analyzed. Results demonstrated statistically significant decreases in DERS-18 scores from pre-intervention to post-intervention at each timepoint. Qualitatively, participants perceived improvements in ER within specified DERS-18 domains. We describe how 3MDR’s unique and novel approach may address ED through cognitive-motor stimulation, narration, divergent thinking, reappraisal of aversive stimuli, dual-task processing, and reconsolidation of traumatic memories. Further investigation is underway to better understand the underlying neurobiological mechanisms by which 3MDR addresses ER and PTSD.
ARTICLE | doi:10.20944/preprints202104.0566.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Varroa destructor; mite; resistant populations; acaricide residues; tau-fluvalinate; varroosis
Online: 21 April 2021 (09:42:13 CEST)
Varroa destructor is considered one of the most devastating parasites of the honey bee, Apis mellifera, and a major problem for the beekeeping industry. Currently, the main method to control Varroa mites is the application of drugs that contain different acaricides as active ingredients. The pyrethroid tau-fluvalinate is one of the acaricides most widely used in beekeeping due to its efficacy and low toxicity to bees. However, the intensive and repetitive application of this compound produces a selective pressure that, when maintained over time, contributes to the emergence of resistant mites in the honey bee colonies, compromising the acaricidal treatments efficacy. Here we studied the presence of tau-fluvalinate residues in hives and the evolution of genetic resistance to this acaricide in Varroa mites from honeybee colonies that received no pyrethroid treatment in the previous four years. Our data revealed the widespread and persistent tau-fluvalinate contamination of beeswax and beebread in hives, an overall increase of the pyrethroid resistance allele frequency and a generalized excess of resistant mites relative to Hardy-Weinberg equilibrium expectations. These results suggest that tau-fluvalinate contamination of the hives may seriously compromise the efficacy of pyrethroid-based mite control methods.
ARTICLE | doi:10.20944/preprints201903.0287.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: resistant; microRNA-21; doxorubicin; PTEN; MCF-7/Dox cell line
Online: 30 March 2019 (06:46:35 CET)
Background: Breast cancer is the leading cause of cancer mortality and morbidity among Indonesian women. Identification of biological pathways leading into therapeutic resistance through in vitro model is an important step to develop alternative effective therapy in breast cancer. Loss of PTEN expression has been associated with resistance to chemotherapy by involving PI3K/PTEN- dependent apoptosis pathway. We conducted in vitro experiment to investigate the association of hsa-miR-21 and PTEN expression in Doxorubicin-resistant MCF-7 cell line. Methods: Parental MCF-7 cells were periodically incubated with Doxorubicin to obtain specific Dox-resistant variant determined by IC50 using MTT assay. PTEN protein expression was analyzed using immunocytochemistry. Expression of mature has-miR-21 was measured using qRT-PCR. Results: The IC50 of Doxorubicin in parental MCF-7 and Doxorubicin-resistant MCF-7 cells (MCF-7/Dox) was 0.68 and 5.78 µg/ml, respectively. Hsa-miR-21 was significantly overexpressed in MCF-7/Dox cells compared to parental MCF cells (7.94 fold changes). Conclusion: PTEN and hsa-miR-21 expression levels were negatively correlated in Doxorubicin resistant-MCF cells. Further study to confirm the causal relationship of miR-21 overexpression and PTEN downregulation in MCF-7/Dox is required.
ARTICLE | doi:10.20944/preprints201811.0420.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: PFAD; urethane acrylate; crosslinking, UV curing, chemical resistant; film hardness
Online: 19 November 2018 (06:40:22 CET)
Palm fatty acid distillate (PFAD) is a by-product from the refining of crude palm oil. It comprises mainly of free fatty acids, having around 45% of palmitic and 33% oleic acids as the major components. Ultra-violet (UV) curable urethane acrylate (UA) oligomers could be synthesized from PFAD by the following procedure. A hydroxyl terminated macromer was first prepared by reacting PFAD with a mixture of isophthalic acid, phthalic anhydride, neopentagylcol (NPG) and pentaerythritol. The macromer is then reacted with 2-hydroxylethylacrylate (2HEA) and toluene diisocynate (TDI) to generate a resin containing acrylate side chains for UV curable application. A series of UA resins were prepared by using 15, 25, 45, 55 and 70% of PFAD respectively. The UA resin has Mw in the range of 3200 to 27,000. They could be cured by UV irradiation at intensity of 225mW/cm2. Glass transition temperature (Tg) of the cured film was measured by differential scanning calorimeter (DSC), and hardness of the film was determined by pendulum hardness tester according to ASTM4366. The resins were used in wood coating application. All of the cured films showed good adhesion, hardness and chemical resistant for resins using up to 55% PFAD; however the resin at 70% did not cure properly.
ARTICLE | doi:10.20944/preprints201807.0335.v2
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: Heat-resistant; Nylon 6; P(N-phenylmaleimide-alt-styrene); Blends;
Online: 16 November 2018 (15:01:35 CET)
In this work, nylon 6/ P(N-phenylmaleimide-alt-styrene) blends were prepared by melt blending, and the mechanical, heat-resistant, crystallographic and dynamical mechanical properties of nylon 6/ P(N-phenylmaleimide-alt-styrene) blends with different contents were investigated and analyzed. The results showed that the mechanical properties decreased with increasing PNS, while the heat deflection temperature (HDT), relative crystallinity (Xn), and storage modulus (G’) increased with increasing PNS. The results of differential Scanning Calorimetry (DSC) proved the PNS played the positive role of nucleating PA6. And the results of dynamic mechanical analysis (DMA) proved the PNS could improve the rigidity of PA6/PNS blends. From the SEM, these PNS domains were between 0.2 and 4 μm in diameter. The experimental results indicated that the addition of PNS improved the rigidity of PA6/PNS blends, and then improved the heat-resistant property.
ARTICLE | doi:10.20944/preprints202310.1202.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: healthcare-associated infections; Intensive Care Unit; cardiovascular diseases, multidrug resistant bacteria
Online: 18 October 2023 (18:26:38 CEST)
Nowadays, healthcare-associated infections (HAIs) represent a major global public health problem and the burden of these infections is high. In order to reduce the incidence of HAIs and to prevent the spread antibi-otics resistant organisms is mandatory to develop surveillance systems. We undertook a retrospective case-control study of all patients presenting HAIs admitted in Intensive Care Unit (ICU) in order to assess risk factors associated with death among patients with HAIs. Patients admitted to Intensive Care Unit who died were more likely to present an infection with a multidrug resistant bacteria, an infection with Acineto-bacter baumannii, and to suffer from acute myocardial infarction. Among the patients enrolled in the study, a higher probability of death was also observed in association with certain gram-negative pathogens: Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa. The longer the patient remains admitted in ICU, the higher the risk of getting an infection that can often become fatal. Acquiring a noso-comial infection also increases the length of hospitalization which will lead to increased financial damage.
ARTICLE | doi:10.20944/preprints202309.0805.v1
Subject: Engineering, Marine Engineering Keywords: marine seismometer; observation platform; pressure-resistant shell; ultimate strength; finite element
Online: 13 September 2023 (05:25:57 CEST)
According to the development needs of marine seismic station networking, it is necessary to develop a marine seismometer with a networking function to realize quasi-real-time and large-scale long-term observation of undersea seismic signals. This can lay a solid foundation for marine seismic research and research on earth tectonics, activities, and processes. Based on the advantages and disadvantages of the existing observation equipment, this study proposed to develop a new type of the Autonomous Glide Marine Seismometer(AGMS) that can be applied to the global sea area, focusing on the design and study of the main structure of the carrier of the AGMS. The ultimate strength of the ellipsoidal pressure-resistant spherical shell is investigated by using the finite element analysis method. A reasonable finite element analysis model is proposed through comparing the finite element parameter results with the theoretical formulas and relevant specifications. Finally, the design process and strength checking of the pressure-resistant shell of the AGMS are established. These relevant results can also provide a reference for the design of other deep-sea pressure-resistant chambers.
ARTICLE | doi:10.20944/preprints202308.0134.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: antimicrobial peptide; drug-resistant bacteria; cathelicidin; multifunction; aromatic and aliphatic residue
Online: 2 August 2023 (10:24:33 CEST)
BMAP-18, derived from the N-terminal region of bovine myeloid antimicrobial peptide BMAP-27, demonstrated potent antimicrobial activity without cytotoxicity. This study aimed to compare the antibacterial, antibiofilm, and anti-inflammatory properties of BMAP-18, rich in aromatic phenylalanine residues, with its aliphatic analogue, BMAP-18-FL. Both aromatic BMAP-18 and aliphatic BMAP-18-FL exhibited equally potent antimicrobial activities against Gram-positive and Gram-negative bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Pseudomonas aeruginosa (MDRPA). Mechanistic investigations employing SYTOX green uptake, DNA binding, and FACScan analysis revealed that both peptides acted by inducing membrane permeabilization and subsequent intracellular targeting. Moreover, both BMAP-18 and BMAP-18-FL effectively prevented biofilm formation and eradicated existing biofilms of MRSA and MDRPA. Notably, BMAP-18-FL displayed superior anti-inflammatory activity compared to BMAP-18, significantly reducing the expression levels of pro-inflammatory cytokines in lipopolysaccharide-stimulated macrophages. This study emphasizes the similarities and differences in the antimicrobial, antibiofilm, and anti-inflammatory properties between aromatic BMAP-18 and aliphatic BMAP-18-FL, providing valuable insights for the development of multifunctional antimicrobial peptides against drug-resistant bacteria.
ARTICLE | doi:10.20944/preprints202305.0627.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Non-headed Chinese cabbage; heat stress; physiological mechanism; heat-resistant varieties
Online: 9 May 2023 (09:40:07 CEST)
Under the increasingly severe global heat threat, continuous high temperature has far-reaching effects on plant growth and development and become a major constraint to crop production. The development of heat-resistant varieties has become research hotspot in many fields, and it is also necessary to establish effective identification methods. In this study, twenty Brassica rapa varieties were selected to to investigate the physiological and biochemical characteristics under heat stress, explore the relationship between physiological response and the heat resistance mechanism, select some typical heat-resistant and heat-sensitive varieties. The effects of photosynthetic electron transfer and antioxidant pathway on heat resistance of Brassica rapa were identified. These findings will providing an important reference for the physiological regulation and identification method of high-temperature stress in plants.
REVIEW | doi:10.20944/preprints202304.1236.v1
Subject: Medicine And Pharmacology, Hematology Keywords: FLT3 mutations; resistant/relapsed acute myeloid leukemia; tyrosine kinase inhibitors; gilteritinib
Online: 29 April 2023 (10:55:21 CEST)
The traditionally dismal outcome of acute myeloid leukemia (AML) patients carrying the FMS-related tyrosine kinase 3 (FLT3) mutations has been mitigated by the recent introduction into the clinics of tyrosine kinase inhibitors (TKI) such as midostaurin and gilteritinib. The present work summarizes the clinical data that led to the use of gilteritinib in clinical practice. Gilteritinib is a 2nd generation TKI with deeper single-agent activity than 1st generation drugs against both FLT3-ITD and TKD mutations, in human studies. Moreover, the phase I/II dose-escalation, dose-expansion Chrysalis trial showed an acceptable safety profile of gilteritinib (diarrhea, elevated aspartate aminotransferase, febrile neutropenia, anemia, thrombocytopenia, sepsis, and pneumonia) and a 49% overall response rate (ORR) in 191 FLT3-mutated relapsed/refractory (R/R) AML patients. In 2019, the pivotal ADMIRAL trial showed that the median overall survival was significantly longer in patients treated with gilteritinib than among those receiving chemotherapy (9.3 vs 5.6 months, respectively) and the ORR to gilteritinib was 67.6%, outperforming the 25.8% for chemotherapy arm and leading to the license for its clinical use by the US Food and Drug Administration. Since then, several real-world experiences confirmed the positive results in the R/R AML setting. Finally, gilterinib based combinations currently under investigation with several compounds (venetoclax, azacitidine, conventional chemotherapy, etc.) and some practical tips (maintenance after allogeneic transplantation, interaction with antifungal drugs, extramedullary disease, and onset of resistance) will be analyzed in detail in the review.
ARTICLE | doi:10.20944/preprints202202.0166.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: microbiological characterization; safety; VanZ; isolation; vancomycin resistant gene; genome; bee; honey
Online: 11 February 2022 (21:17:45 CET)
Bifidobacteria have long been recognized as bacteria with probiotic and therapeutic features. The aim of this work is to characterize the Bifidobacterium asteroides BA15 and BA17 strains, isolated from honeybee gut. An in-depth assessment was carried out on safety properties (antibiotic resistance profiling, β-haemolytic, DNAse and gelatinase activities and virulence factor presence) and other properties (antimicrobial activity, auto-aggregation, co-aggregation and hydrophobicity). Based on phenotypic and genotypic characterization, both strains satisfied all the safety requirements. More specifically, genome analysis showed the absence of genes encoding for glycopeptide (vanA, vanB, vanC-1, vanC-2, vanD, vanE, vanG), resistance to tetracycline (tet-M, tet-L and tetO), and virulence genes (asa1, gelE, cylA, esp, hyl).
ARTICLE | doi:10.20944/preprints202104.0385.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: antibiotic resistance; antimicrobial susceptibility testing; novel diagnostics; polymicrobial; sputum; drug resistant
Online: 14 April 2021 (14:21:15 CEST)
For polymicrobial infections, AtbFinder utilizes a novel paradigm of the population response to antibiotics, enabling bacterial growth in the form of a mixed microbial community and selecting the antibiotics targeting not only the principal pathogen, but also those bacteria that support their growth. TGV medium allowed culturing a more diverse set of bacteria from polymicrobial biospecimens, compared with that achieved with the standard media and enabled, already within 4h, accurate selection of the antibiotics that completely eliminated all cultivatable bacteria from clinical samples. In conclusion, AtbFinder system may be a valuable tool in improving antibiotic selection, enabling targeted empirical therapy and accurate antibiotic replacement, which is especially important in high-risk patients.
ARTICLE | doi:10.20944/preprints202103.0147.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Candida sp.; head - neck tumor; innovative antifungals; azole-resistant; Ruta graveolens.
Online: 4 March 2021 (09:18:46 CET)
The problem of drug resistance in terms of antifungal therapy, unknown until a few years ago, is assuming increasing importance. Particularly in immunosuppressed patients and subject to chemotherapy and radiotherapy. In the last years the use of essential oils as approach to improving the effectiveness of antifungal agents and reducing the antibiotic resistant has been proposed. Our research aimed to evaluate the antifungal activity of Colombian essential oil of Ruta graveolens (REO) against clinical strains of Candida albicans, Candida parapsilopsis, C. glabrata and Candida tropicalis. The data obtained showed that Candida tropicalis and Candida albicans were most sensible strains showing minimum inhibitory concentrations (MIC) of 0.5 and 1.0 µg/ml of REO. The Time Kill Kinetics assay demonstrated that REO showed fungicide effect against C. tropicalis and fungistatic effect against C. albicans. In addition, the 40% of the biofilm formed by C. albicans was eradicated using 1% of REO after 1 hour of exposure.
ARTICLE | doi:10.20944/preprints201810.0236.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: essential oils; drug resistant microorganisms; antimicrobial activity; antifungal activity; medicinal plants
Online: 11 October 2018 (11:51:16 CEST)
Antimicrobial resistance (AMR) is a recurring global problem, which constantly demands new antimicrobial compounds to challenge the resistance. It is well known that essential oils (EOs) have been known for biological activities including antimicrobial properties. In this study, EOs from seven aromatic plants of Asir region of southwestern Saudi Arabia were tested for their antimicrobial efficacy against four drug resistant pathogenic bacterial isolates (Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Streptococcus typhimurium) and one fungal isolate (Candida albicans). Chemical compositions of EOs were determined by Gas chromatography-Mass Spectrometry (GC-MS). The results revealed that EOs from Mentha cervina, Ocimum basilicum and Origanum vulgare proved most active against all isolates with inhibitory zone range between17 to 45 mm. The lowest minimum inhibitory concentration (MIC) of 0.025mg/ml was observed for Staph. aureus and Streptococcus pyogenes with EO of Origanum vulgare. All the three EOs showed significant anti candida activity. Together form the results the EOs from Mentha cervina, Ocimum basilicum and Origanum vulgare demonstrated a significant antimicrobial efficacy against drug resistant microorganisms.
ARTICLE | doi:10.20944/preprints202311.0108.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antibacterial activity; SnO2-CoFe2O4 nanocomposite; Multidrug-resistant; E. coli; Urinary tract infections
Online: 2 November 2023 (08:11:00 CET)
Urinary tract infections (UTIs) caused by pathogens, particularly E. coli, have spontaneously become resistant to antimicrobial drugs in recent years. Therefore, regular monitoring and alternative strategies for the antimicrobial agent are crucial for combating antimicrobial resistance and bacterial biofilms. Here, we report a new cobalt iron oxide-conjugated tin oxide nanocomposite that can kill bacteria and treat multidrug-resistant E. coli posing UTIs. Following the isolation and identification of E. coli, we tested 57/134 samples against sixteen commonly used antibiotics phenotypically using the disk diffusion method to determine their sensitivity pattern. Of the 57 E. coli isolates, 66% (38/57) were multidrug-resistant. The E. coli isolates were resistant to cephradine (70.17%), ceftriaxone (59.64%), and azithromycin (59.64%), followed by cefixime (54.38%), cefuroxime sodium (52.63%), and co-trimoxazole (50.87%). X-ray diffraction results showed the crystallite sizes were about 5.68 and 8.84 nm in pure SnO2 nanoparticles and 95% SnO2-5% CoFe2O4 nanocomposite, respectively. Energy-dispersive X-ray spectroscopy and Fourier transform infrared determined the fundamental structure of the nanocomposite, encompassing Co, Fe, Sn, and O. Moreover, FTIR measurements implied that the distinct functional groups in both SnO2 and CoFe2O4 nanoparticles existed in a 95% SnO2-5% CoFe2O4 nanocomposite. Field emission scanning electron microscope analysis uncovered that the SnO2-CoFe2O4 nanocomposite had a size of roughly 24 nm and was spherical. In addition, the biosynthesized SnO2 nanoparticles and SnO2-CoFe2O4 nanocomposite were evaluated for their antibacterial activity. At a minimum 100 µg/mL concentration, SnO2 nanoparticles and SnO2-CoFe2O4 nanocomposite showed high antibacterial activity. The SnO2 nanoparticles and SnO2-CoFe2O4 nanocomposite demonstrated antibacterial activity on multidrug-resistant E. coli at 10 ± 0.7 and 16 ± 0.8 mm zone of inhibition, respectively. In conclusion, the new SnO2-CoFe2O4 nanocomposite might be a potential candidate for treating UTIs caused by drug-resistant E. coli in the foreseeable future.
REVIEW | doi:10.20944/preprints202308.0476.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: drought stress; wheat genotypes; drought-resistant cultivars; genotype-dependent responses; wheat diversity
Online: 7 August 2023 (07:33:21 CEST)
Drought stress imposes substantial constraints on the growth and production of wheat (Triticum aestivum L.), a globally important cereal crop that is essential for food security. To mitigate these adverse effects, researchers are intensifying their efforts to comprehend how different genotypes respond to drought stress, aiding in the development of sustainable breeding and management strategies. This review summarized past and recent research on genotype-dependent responses of wheat to drought stress, encompassing morphological, physiological, biochemical, molecular, genetic, and epigenetic reactions in plants. Screening of drought-affected features at early developmental stages can provide valuable insights into the adult growth stages that are closely linked to plant productivity. The review underscores the importance of identifying key traits associated with drought resistance, and the potential of leveraging wheat diversity to select cultivars with desirable agronomic characteristics. It also highlights recent advancements in investigating Bulgarian wheat genotypes with varying levels of drought tolerance, specifically in detecting essential features contributing to drought tolerance. Cultivating drought-resistant wheat genotypes and understanding stress stability determinants could markedly contribute to enhancing wheat production and ensuring stable yields under changing climate conditions.
ARTICLE | doi:10.20944/preprints202307.1547.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Antimicrobial Resistant; heteroaryl-ethylene derivatives; QSAR model; Antibiotics; Antitumour compounds; Combination Therapy
Online: 24 July 2023 (09:26:48 CEST)
: Introduction: Discovering compounds with antibacterial activity is crucial in the current fight against antibiotic-resistance. Material and Methods: We generate two QSAR model to design six new heteroaryl drug candidates; we assessed the antibacterial properties of the compounds against nine ATCC strains, the majority being part of the ESKAPE group, that include Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and also Salmonella enterica and Escherichia coli. We performed a synergic assay in which we combined PB4, a compound that we have previously tested in published studies, with GC-VI-70, one of the new compounds with the best cytotoxicity/MIC profile. We tested sub-MIC concentrations of PB4 with five antibiotics (linezolid, gentamycin, ampicillin, erythromycin, rifampin and imipenem) to examine the synergic effect on the ATCC strains. To evaluate compounds’ cytotoxicity, we performed a 24-hour and 48-hour 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on Colorectal Adenocarcinoma (CaCo-2) cells. The antibiotics were tested, alone and in combination with PB4. Results: PB4 lowered the MIC measured for GC-VI-70 and for the various antibiotics employed in clinical use, and all the compounds presented in this study have cytotoxic activity against cells. Conclusions: These compounds show promising use in combination with antibiotics to improve their effectiveness at low concentrations, to prevent unwanted cytotoxic effects.
ARTICLE | doi:10.20944/preprints202306.2188.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: carbapenem-resistant Enterobacteriaceae (CRE); carbapenemase-producing Enterobacteriaceae (CPE); death toll; epidemiologic characteristic
Online: 30 June 2023 (09:26:57 CEST)
The incidence of carbapenem-resistant Enterobacteriaceae (CRE) has been increasing considerably annually since being first reported in 2008. Gyeonggi Province has the largest number of healthcare facilities in South Korea, which contribute to its regional vulnerability to CRE infections. Thus, there is a need to obtain up to date information on the occurrence of CRE infections in the Gyeonggi Province to take corrective measures. Therefore, in this study, we aimed to investigate the overall trends of CRE occurrence in Gyeonggi Province over the past 4 years and the epidemiological characteristics of CRE-related mortality. Patients admitted to a healthcare facility in Gyeonggi Province from January 2018 to December 2021 with positive blood cultures to CRE were included in the study and investigated. Additionally, the risk factors for CRE-related death were determined using data from CRE-positive patients who died within 30 days of last blood sampling. Older adults aged 70 and over accounted for the highest percentage of both survivors and non-survivors with CRE bacteremia. The number of non-survivors was higher in tertiary hospitals and among patients in intensive care unit. There were no significant differences in the mortality risk according to the use of antibiotics. Moreover, non-survivors were predominant among patients with hypertension, malignant tumor, and those having two or more underlying diseases. Klebsiella pneumoniae was the most common CRE strain in both survivors and non-survivors. Among the survivors, carbapenemase-producing Enterobacteriaceae was detected in 151 cases (71.2%) and 49 cases (23.1%) in the KPC and NDM groups, respectively. Among the non-survivors, it was detected in 25 cases (86.2%) and 5 cases (17.2%) in the KPC and NDM groups, respectively. The endemicity of CRE in South Korea has been proposed for several years; our results have suggested endemicity of CRE in the Gyeonggi Province. Despite the strengthened infection control policies in healthcare facilities during the pandemic, there has been an increasing trend in the isolation of CRE strains in South Korean long-term care hospitals and hospitals within Gyeonggi Province. Factors such as history of hospitalization and underlying diseases have been identified as risk factors for CRE-related deaths. However, to address this issue strictly, it is important to establish infection control infrastructure tailored based on each type of healthcare facility, and elaborate specific government support measures, accordingly.
ARTICLE | doi:10.20944/preprints202101.0524.v5
Subject: Physical Sciences, Nuclear And High Energy Physics Keywords: elementary dimensions; absolute void; early universe; universe at zero second; Void resistant
Online: 5 January 2022 (10:35:44 CET)
In this study, we discuss the properties of absolute vacuum space and how these properties can play a vital role in creating a mechanism in which the very first particle gets created simultaneously everywhere and we find the limit in which when the absolute vacuum volume reaches will lead to the collapse that leads to the creation of the first particle. This discussion is made following to the elementary dimensions theory study that was peer-reviewed at the end of 2020, everything in the universe is made from four elementary dimensions, these dimensions are the three spatial dimensions (X, Y, and Z) and the Vacuum resistant as the factor of change among the four, time itself wasn’t considered as the fourth dimension, rather time corresponds to a factor of change, and during the research it was found out that the Vacuum resistant is the factor of change in the Absolute Vacuum space, where time is a hypothetical concept, that represents changes during certain events compared to a constant change rate event.Therefore, time does exist, but as a factor of change, and as the Vacuum resistant in the absolute vacuum space, Time= factor of change= Vacuum resistant. In the study, the internal and external vacuum resistant volume equivalent is found, External Vacuum resistant=3.2857602*10^15 *mass. This equation is used to identify the amount of Free external vacuum resistant created during nuclear fission and fusion: Initial mass of the excited nucleuses mass of the created new nucleuses+ 3.2857602*10^15 * the lost Mass. In elementary dimensions, the energy created during nuclear reactions is equivalent to the free External vacuum resistant created through nuclear reactions, and mass is equivalent to the internal Vacuum resistant.
ARTICLE | doi:10.20944/preprints202004.0448.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: acetyleugenol; Acacia nilotica; anti-tuberculosis; Serine/Threonine kinases; multi-drug resistant TB
Online: 24 April 2020 (14:12:33 CEST)
Acetyleugenol is a phytochemical compound with broad effect against infectious diseases and tumors. Here, we extracted, characterized and elucidated the structure of acetyeugenol, for the first time, from the leaves of Acacia nilotica (L.)―a well-known medicinal plant. The broad antibacterial potential of acetyleugenol was first confirmed against seven bacterial pathogenic isolates with best activity against Proteus sp., Salmonella typhi, Staphylococcu aureus, and Streptococcus pneumonia, which showed similar or better zone of inhibition to that of the control amoxicillin. To further investigate its effect against Mycobacterium tuberculosis, acetyleugenol and its indole and phenyl analogs were subjected to molecular docking experiments against two potential tuberculosis drug targets―MtPknE and MtPknB Ser/Thr protein kinases. The results reveal that all of the analogs have improved docking scores comparing to the acetyleugenol. The indole analogs EUG-1 and EUG-3 were more effective with better docking scores for MtPknE with –11.08 and –10.05 kcal/mol, respectively. Similar results were obtained for the MtPknB. In contrast, only the EUG-2 phenyl analog has given rise to similar docking scores for both targets. This opens the door for further comprehensive studies on these acetyleugenol analogs with in vitro and in vivo experiments to validate and get more insights into their mechanisms of action.
ARTICLE | doi:10.20944/preprints201904.0142.v1
Subject: Medicine And Pharmacology, Urology And Nephrology Keywords: NGF/TrkA signaling; mitogenesis; invasiveness; EMT; 3D models; castrate-resistant prostate cancers
Online: 11 April 2019 (12:55:18 CEST)
Resistance to hormone therapy and disease progression is the major challenge in clinical management of prostate cancer (PC). Drugs currently used in PC therapy initially show a potent antitumor effect. Nevertheless, PC gradually develops resistance, relapses and spreads. Most patients develop, indeed, castrate-resistant PC (CRPC), which is almost incurable. The nerve growth factor (NGF) acts on a variety of non-neuronal cells by activating the NGF tyrosine-kinase receptor, TrkA. NGF signaling is deregulated in PC. In androgen-dependent PC cells, TrkA mediates the proliferative action of NGF through its cross talk with the androgen receptor (AR). Epithelial PC cells, however, acquire the ability to express NGF and TrkA, as the disease progresses, indicating a role for NGF/TrkA axis in PC progression and androgen-resistance. We here report that once activated by NGF, TrkA mediates proliferation, invasiveness and epithelial-mesenchyme transition (EMT) in various CRPC cells. NGF promotes organoid growth in 3D models of CRPC cells, and specific inhibition of TrkA impairs all these responses. Thus TrkA represents a new biomarker to target in CRPC.
ARTICLE | doi:10.20944/preprints202309.1057.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: vancomycin-resistant enterococcus faecium; hospital epidemic; whole genome analysis; infection prevention and control
Online: 15 September 2023 (11:41:52 CEST)
Vancomisin resistant enterococcus(VRE), is a resistant microorganism which colonizates and causes infections in hospitalized patients. It was aimed to show the spread of vancomycin-resistant Enterococcus (fVREfm) step-by-step in all intensive care units, which started with the growth of vancomycin-resistant Enterococcus faecium (VREfm) on 02.12.2021 in the blood culture of a patient hospitalized in the anesthesia intensive care unit of our hospital and was found to have reached epidemic size in the surveys. Rectal swab samples were taken from all patients hospitalized in intensive care units, VRE colonization was determined and the VanA and VanB resistance genes associated with vancomycin resistance of VREfm isolates were determined by PCR method, and clonal association analysis was performed by Arbitrarily Primed-PCR (AP-PCR) and Pulsed-Field Gel Electrophoresis. In our study, VRE was detected in 61 of 2601 rectal swab samples. 54 (85.52%) of the VRE isolates were Enterococcus faecium, 3 (4.91%) was Enterococcus faecalis, 3 (4.91%) was Enterococcus gallinorum, 1 (1.63%) was Enterococcus casseliflavus. It was determined that all of the 54 VREfm isolates, which were the most detected among all VRE isolates, carried the vanA gene. In the clonal association analysis of the isolates by AP-PCR and PFGE methods, it was found that they had 12 different genotypes, 48 of them were included in any cluster, the clustering rate was 88.8%, and the largest cluster was genotype 1 cluster with 36 isolates. Of the 54 patients with VREfm isolated recently, 18.51 percent of the clinical samples were isolated before the survey, and 9.24% were isolated after the survey. It was determined that 100% of VREfm isolates were resistant to ampicillin, levofloxacin, ciprofloxacin, high-level gentamicin, trimethoprim-sulfamethoxazole, teicoplanin, 7.4% to tigecycline and 1.85% to linezolid. In our study, in the clonal association analysis performed by isolating VREfm in rectal swab samples, it was found that 88.8% of the samples were indistinguishably similar and the increase in the number of VREfm infections after the index case in our hospital was associated with the epidemic. VREfm infections cause long term hospitalization, costs and also deaths, which shows the seriousness of the event, and the importance of the combination of epidemiological and molecular analysis in epidemic research.
ARTICLE | doi:10.20944/preprints202307.1122.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: resistant maltodextrin; pasteurized orange juice; sensory evaluation; physico-chemical properties; volatile aroma compounds
Online: 17 July 2023 (13:27:05 CEST)
Although the beneficial health effects of prebiotics have been demonstrated in numerous research papers, its incorporation into daily food remains unfamiliar to consumers. This work evaluates the resistant maltodextrin (RMD) addition in the sensory attributes of pasteurized orange juice, together with the physico-chemical properties and the aromatic profile. RMD addition moderately improved almost all sensory attributes evaluated by panellists. It also proportionally increased °Brix together with density and decreased acidity. Colour changes were registered with higher RMD concentrations. Orange pulp presence affected the volume particle size distribution analysis while RMD addition did not exercised any effect. The aroma volatile compounds were also analysed. Pulp-added samples marked higher alcohol and aldehydes quantity, whereas pulp-free samples registered higher terpenes and terpenoids values. Ketones and acids were also quantified. RMD had a moderate impact on volatile compounds quantifications, playing the orange pulp presence a much more decisive role. A correlation analysis was also performed to relate instrumental and sensorial determinations for all samples. This work proves that the addition of RMD to orange juice is technologically feasible while also achieving a good response at the sensory level.
ARTICLE | doi:10.20944/preprints202306.2125.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: H. pylori; antibiotics resistant; Z. officinale antibacterial; biofilm suppression; anti-inflammatory; GC-MS
Online: 29 June 2023 (13:17:17 CEST)
The increased emergence of multidrug-resistant Helicobacter pylori influences the prevention of stomach cancer. Zingiber officinale is a plant usually used in folk medicine to treat a variety of diseases involving infections, nausea, vomiting, peptic ulcer, dyspepsia, and inflammation. This study was conducted to evaluate the ability of Z. officinale extract to combat resistant H. pylori. The disc diffusion, microdilution, and microplate assays were performed to evaluate the susceptibility to antibiotics, and the antibacterial and antibiofilm activities of the Z. officinale extracts. Using the checkerboard method, the combined effects of the gentamicin and Z. officinale extract were investigated. In addition, anti-inflammatory activity and GC-MS analysis were determined by the modified protocol. According to the findings, H. pylori isolates exhibited resistance rates of 56.33, 50.0, and 45.85 for metronidazole, gentamicin, and tetracycline, respectively. The methanolic extract of Z. officinale had the strongest effectiveness against resistant H. pylori isolates with MIC of 20.0 to 50.0 µg/ml against both H. pylori isolates and the stranded strain NCTC 11637. Z. officinale extract suppress the biofilm formed by H. pylori isolates with a percentage of 92.96% at 50.0µg/ml, compared with 97.19% for gentamicin at the same concentration. According to FICI values, combination of methanolic Z. officinale extract to gentamicin increases bacterial sensitivity to such drugs. Moreover, the Z. officinale extract exhibits strong anti-inflammatory activity. The GC-MS analysis of Z. officinale extract exhibits 17 different chemical compounds. Conclusions: The Z. officinale extract contain the anti-inflammatory compound gingerol as the main constituent which inhibits the growth of H. pylori and its biofilm, are a promising natural therapeutic alternative or enhance antibiotics activity
REVIEW | doi:10.20944/preprints201912.0179.v1
Subject: Biology And Life Sciences, Biophysics Keywords: globular set; category theory; multidimensional; visual recognition; drug-resistant epilepsy; transcranial magnetic stimulation.
Online: 13 December 2019 (10:37:03 CET)
Once a wheat sheaf has been sealed and tied up, its packed down straws display the same orientation and zero-divergence. This observation brings us to the mathematical notion of presheaf, i.e., a topological structure in which diverging functions are locally superimposed. We show how the concepts of presheaves and the correlated globular sets, borrowed from category theory and algebraic topology, allow a well-founded mathematical approach to otherwise elusive activities of the brain. The mathematical assessment of brain functions in terms of presheaves: a) explains why spontaneous random spikes synchronize; b) leads to the counterintuitive intuition of antidromic effects in neuronal spikes: when an entrained oscillation propagates from A to B, changes in B lead to changes in A. We provide testable previsions: a) we suggest the proper locations of transcranial magnetic stimulation’s coils to improve the clinical outcomes of drug-resistant epilepsy; b) we advocate that axonal stimulation by external sources backpropagates and alters the neuronal electric oscillatory frequency. Further, we describe how the hierarchical information transmission inside globular sets provides fresh insights concerning different issues at various coarse-grained scales, such as object persistence, memory reinforcement in spite of random noise, Bayesian inferential circuits.
ARTICLE | doi:10.20944/preprints202311.1017.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: prostate cancer; castration-resistant prostate cancer; molecular profiling; data integration; precision medicine; essential genes
Online: 16 November 2023 (03:11:59 CET)
Prostate cancer (PCa) is characterised by androgen-dependency. Unfortunately, under anti-androgen treatment pressure, castration-resistant prostate cancer (CRPC) emerges, characterised by heterogeneous cell populations that, over time, lead to the development of different androgen-dependent or -independent phenotypes. Despite important advances in therapeutic strategies, CRPC remains incurable. Context-specific essential genes represent valuable candidates for targeted anti-cancer therapies. Through the investigation of gene and protein annotations and the integration of several published transcriptomic data, we identified two consensus lists to stratify PCa patients' risk and discriminate CRPC phenotypes based on androgen receptor activity. ROC and Kaplan-Meier survival analyses were used for gene set validation in independent datasets. We further evaluated these genes for their association with cancer dependency. The deregulated expression of the PCa-related genes was associated with overall and disease-specific survival, metastasis and/or high recurrence risk, while the CRPC-related genes clearly discriminated between adeno and neuroendocrine phenotypes. Some of the genes showed context-specific essentiality. We further identified candidate drugs through a computational repositioning approach for targeting these genes and treating lethal variants of PCa. This work provides a proof-of-concept for the use of an integrative approach to identify candidate biomarkers involved in PCa progression and CRPC pathogenesis within the goal of precision medicine.
ARTICLE | doi:10.20944/preprints202308.0982.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Kluyveromyces marxianus DMKU3-1042; Kluyveromyces marxianus DMKU3-118; stress-resistant mutant; pseudohyphae formation; SWI5
Online: 14 August 2023 (04:43:52 CEST)
Kluyveromyces marxianus is an attractive thermotolerant yeast species for ethanol production because of its ability to utilize various carbon sources as a fermentation substrate. The use of thermotolerant microbes enables performance of high-temperature ethanol fermentation, which has several advantages including reduction of cooling costs and minimization of contamination risk. To improve K. marxianus for ethanol fermentation under stress conditions, two strains, DMKU 3-1042 and DMKU 3-118, were adapted for heat resistance and toxic substances in pulp wastewater from a paper mill, respectively, resulting in the generation of KMR1042 and KMR118, respectively. Both adapted mutants exhibited clumpy clusters of cells as pseudohyphae and altered colony morphology, and their sedimentation speeds were much faster than those of the corresponding parent strains. The two mutants showed stronger tolerance to various stresses and higher performance for ethanol production than those of the corresponding parent strains at high temperatures or in the presence of toxic substances. Genome sequencing analysis revealed that both mutants had disruption of the same gene, SWI5, despite adaptation under different stress conditions, suggesting that the formation of pseudohyphae is a common strategy of K. marxianus for coping with stresses.
REVIEW | doi:10.20944/preprints202305.1710.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: prostate cancer; immunotherapy; dendritic cell-based vaccines; castration-resistant prostate cancer; tumor microenvironment; biomarkers
Online: 24 May 2023 (10:47:44 CEST)
Prostate cancer (PCa) is the most commonly diagnosed cancer and the second most common cause of death due to cancer. About 30% of patients with PCa who have been castrated develop a castration-resistant form of the disease (CRPC), which is incurable. In the last decade, new treatments that control the disease have emerged, slowing progression and spread, and prolonging survival while maintaining the quality of life. These include immunotherapies; however, we do not yet know the optimal combination and sequence of these therapies with the standard ones. All therapies are not always suitable for every patient due to co-morbidities or adverse effects of therapies or both, so there is an urgent need for further work on new therapeutic options. Advances in cancer immunotherapy with an immune checkpoint inhibition mechanism (e.g., ipilimumab, an anti-CTLA-4 inhibitor) have not shown a survival benefit in patients with CRPC. Other immunological approaches have also not given clear results, which has indirectly prevented breakthrough for this type of therapeutic strategy into clinical use. Currently, the only approved form of immunotherapy for patients with CRPC is a cell-based medicine, but it is only available to patients in some parts of the world. Based on the experience gained from recently completed clinical research on immunotherapy with dendritic cell-based immunohybridomas, the aHyC dendritic cell vaccine, for patients with CRPC, we highlight the current status, and possible alternatives that should be considered in the future.
ARTICLE | doi:10.20944/preprints202208.0076.v1
Subject: Engineering, Civil Engineering Keywords: Limit analysis of domes; Concrete caps; experiment comparison; Not Tensile Resistant Materials; Finite element
Online: 3 August 2022 (07:20:00 CEST)
The calculation of the collapse load of spherical domes is addressed using a semi-analytical approach under the hypotheses of small displacements and perfect plasticity. The procedure is based on the numerical approximation of the self-stress that represents the projection of the balance equilibrium null space on a finite dimensional manifold. The so obtained self-equilibrated stress span is superimposed to a finite element linear elastic solution to the prescribed loads yielding to the statically admissible set accordingly to Melan’s theorem. The compatibility of the stress with the constitutive law of the material has been enforced using linearized limit domain in terms of generalized stress, namely axial force and bending moment along the local spherical curvilinear coordinates. The procedure has been tested with reference to numerical and experimental data from the literature confirming the accuracy of the proposed method. The comparison with the literature confirms that the buckling load is much greater than the plastic collapse loads both calculated through the proposed procedure and reported in the quoted literature.
ARTICLE | doi:10.20944/preprints201810.0211.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: lipoprotein; extracellular vesicles; exosome; ectosome; stress response; resistant cancer; metastatic cancer; heat shock stress
Online: 10 October 2018 (09:44:17 CEST)
Resistant cancer often shows a particular secretory trait such as heat shock proteins (HSPs) and extracellular vesicles (EVs), including exosomes and oncosomes surrounded by lipid bilayers. Lipoproteins are biochemical assemblies that transport hydrophobic lipid (a.k.a. fat) molecules in body fluid and are composed of a single-layer phospholipid and cholesterol outer shell, lipids molecules within the particles, and apolipoproteins embedded in the membrane. However, lipoprotein storage and secretion by cancer cells have not well-investigated yet. We found lipoproteins were stored and abundantly secreted by neuroendocrine, castration-resistant prostate cancer (NEPC / CRPC) cells but barely secreted by colon cancer cells and oral squamous cell carcinoma (OSCC) cells. In addition, large EVs (approx. 300 nm diameter) and potential oncosomes were released by CRPC and OSCC cells. Proteomics revealed that CRPC cells secreted EVs enriched with tetraspanins and extracellular matrices which were reduced upon heat shock stress and alternatively lipoproteins and HSPs were secreted upon stress. Heat shock stress triggered secretion of lipoprotein-EV complexes that contained apolipoprotein A, B, C and E. These data suggested that vesicular assembly composed of EVs and lipoproteins enriched with cholesterols and phospholipids may be stored in resistant cancer cells but released upon cell stress that is increased in cancer therapies.
ARTICLE | doi:10.20944/preprints201703.0017.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: green synthesis; silver nanoparticles; trimethylchitosan nitrate; catalytic activity; antibacterial activity; multidrug-resistant Acinetobacter baumannii
Online: 2 March 2017 (08:49:35 CET)
We report a facile route for the green synthesis of trimethylchitosan nitrate-capped silver nanoparticles (TMCN-AgNPs) with positive surface charge. In this synthesis, silver nitrate, glucose, and trimethyl chitosan nitrate (TMCN) were used as silver precursor, reducing agent, and stabilizer, respectively. The reaction was carried out in a stirred basic aqueous medium at room temperature without the use of energy-consuming or expensive equipment. We investigated the effects of the concentrations of NaOH, glucose, and TMCN on the particle size, zeta potential, and formation yield. The AgNPs were characterized by UV-visible spectroscopy, photon correlation spectroscopy, laser Doppler anemometry, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The catalytic activity of the TMCN-AgNPs was studied by the reduction of 4-nitrophenol using NaBH4 as a reducing agent. We evaluated the antibacterial effects of the TMCN-AgNPs on Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus using the broth microdilution method. The results showed that both gram-positive and gram-negative bacteria were killed by the TMCN-AgNPs at very low concentration (< 6.13 μg/mL). Moreover, the TMCN-AgNPs also showed high antibacterial activity against clinically isolated multidrug-resistant A. baumannii strains, and the minimum inhibitory concentration (MIC) was ≤ 12.25 μg/mL.
ARTICLE | doi:10.20944/preprints202311.1769.v1
Subject: Computer Science And Mathematics, Mathematics Keywords: Proxy re-encryption; re-encryption simulatability; honest re-encryption attacks; learning with errors; quantum-resistant
Online: 28 November 2023 (10:22:47 CET)
Proxy re-encryption (PRE) is a momentous and widely used cryptographic technique. It enables a proxy to forward ciphertext without the need of decryption. PRE has received significant interest in applications like cloud computing, blockchain, and the Internet of Things. Despite its wide range of uses, PRE has also been subject to new security and privacy regulations. In PKC’19, Cohen $et~al.$~first drew attention to the weakness in PRE's security against chosen-plaintext attacks (CPA) and put up a more stringent security concept known as security against honest re-encryption attacks (HRA). Notably, Cohen provides a beneficial conclusion as well. It is proveded that PRE schemes with re-encryption simulatability property can be elevated from CPA to HRA security. It is also proved that CPA-secure PRE schemes with re-encryption simulatability property can be directly elevated to those satisfying HRA security. However, those PRE schemes with re-encryption simulatability are almost always based on pairings. In this study, to the best of our knowledge, we directly construct HRA-secure PRE with re-encryption simulatability for the first time based on the learning with errors (LWE) assumption, which was widely believed to be quantum-resistant. Based on the re-encryption key generation algorithm and the re-encryption algorithm construction method of the above scheme, we can modify attribute-based conditional proxy re-encryption (AB-CPRE) as well as the corresponding attribute-based proxy re-encryption (AB-PRE) algorithm to make them have re-encryption simulatability properties. Finally, by using this property, We boost the security of AB-CPRE scheme of ESORICS'21 from CPA to HRA and simplify the HRA-security proof for the AB-PRE of ESORICS'21.
ARTICLE | doi:10.20944/preprints202309.0410.v1
Subject: Engineering, Civil Engineering Keywords: Earthquake-resistant structures; Capacity design; Ductile truss beam-to-column joint; Experimental tests; Nonlinear modelling.
Online: 7 September 2023 (03:31:01 CEST)
This paper presents the experimental and numerical study on a ductile beam-column connection between a composite reinforced concrete truss (CRCT) beam and Concrete Filled Tube (CFT) column subjected to bending and shear loads. Two experimental models with different beam-column joint testing schemes, extracted from the same prototype three-dimensional structure designed according to the rules of the capacity design provided by seismic code, were subjected to quasi-static cyclic tests by applying gravitational loads and the horizontal seismic force. The main objective of this paper is to verify the experimental ductile behavior of both specimens and to simulate the experimental global and local response by nonlinear static analysis considering different modelling approaches. The comparison between the experimental and numerical results highlights, for both models considered, the ductile and dissipative capacity of the connection system, designed following the criterion of the hierarchy of resistances proposed by the current Italian code. Different experimental setup showed similar results demonstrating the repeatability of the test and its reproducibility through the nonlinear numerical analysis.
ARTICLE | doi:10.20944/preprints202305.0648.v1
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: carbapenem-resistant Klebsiella pneumoniae; whole genome sequencing; core genome single-nucleotide polymorphism analysis; molecular epidemiology
Online: 9 May 2023 (11:57:43 CEST)
Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a serious public health issue. Aim of the study was to identify the antimicrobial resistance and accessory genes, the clonal relatedness and the evolution dynamics of selected CRKP isolates recovered in an adult and a pediatric intensive care unit of a tertiary hospital in Greece. Methods: Twenty-four CRKP isolates recovered during 2018-2022 were included in the study. Next-generation sequencing was performed using the Ion Torrent PGM Platform. The identification of the plasmid content, MLST and antimicrobial resistance genes, as well as the comparison of multiple genome alignments and the identification of core genome single-nucleotide polymorphism sites, were performed applying various bioinformatics software. Results: The isolates belonged to eight sequence types 11, 15, 30, 35, 39, 307, 323, and 512. A variety of carbapenemases (KPC, VIM, NDM and OXA-48) and resistance genes were detected. CRKP strains shared visually common genomic regions with the reference strain (NTUH-K2044). ST15, ST323, ST39, and ST11 CRKP isolates presented on average 17, 6, 16 and 866 recombined SNPs, respectively. All isolates belonging to ST15, ST323 and ST39 were classified in distinct phylogenetic branches, while ST11 isolates were assigned to a two-subclade branch. For large CRKP sets, the phylogeny seems to change approximately every seven SNPs. Conclusion: The current study provides insight into the genetic characterization of CRKP isolates in the ICUs of a tertiary hospital. Our results indicate clonal dispersion of ST15, ST323, and ST39 and highly diverged ST11 isolates.
ARTICLE | doi:10.20944/preprints202011.0065.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Carbapenem resistant Enterobacteriaceae (CRE); E.coli; Antimicrobial Resistance; Multidrug resistance; Phylogenetic diversity; chicken; food animals; Antimicrobials
Online: 2 November 2020 (17:14:31 CET)
Carbapenem resistant Enterobacteriaceae (CRE) has been public health risk in several countries and recent reports indicate the emergence of CRE in food animals. This study was conducted to investigate the occurrence, resistance patterns, and phylogenetic diversity of CRE E.coli from chicken. Routine bacteriology, PCR detection of E.coli species, multiplex PCR to detect carbapenemase encoding genes and phylogeny of CRE E. coli were conducted. The results show that 24.36 % (19/78) were identified as CRE based on the phenotypic identifications of which 17 were positive for the tested carabanemase genes. The majority, 57.99% (11/19) of the isolates harbored multiple carbapenemase genes. Four isolates harbored all blaNDM blaOXA, blaIMP, five and two different isolates harbored blaNDM and blaOXA, and blaOXA and blaIMP respectively. The Meropenem, Imipenem and Ertapenem MIC values for the isolates ranged from 2g/mL to ≥256g/mL. Phylogenetic grouping showed that the CRE E.coli isolates belonged to five different groups; groups A, B1, C, D and unknown. The detection of carbapenem resistant E.coli in this study shows that CRE is has become an emerging problem in farm animals, particularly, in poultry farms. This also implies the potential public health risks posed by CRE from chicken to the consumers.
ARTICLE | doi:10.20944/preprints202310.0589.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Daptomycin; PMMA cement; mechanical properties; elution; antimicrobial effectiveness; inhibition zone test; Vancomycin-resistant germs; PMMA spacer
Online: 10 October 2023 (07:17:42 CEST)
Background: Number of joint infections caused by Vancomycin-resistant pathogens is emerging. Currently no PMMA cement is commercially available to cover VRE. Daptomycin shows promising results in infection treatment, offers a good safety profile and reduced risk for resistance development. Purpose of this in vitro study is to investigate the mechanical stability, handling properties, elution behavior and antimicrobial effectiveness of PMMA cement loaded with three different Daptomycin concentrations in comparison to commercially available ALBC; Methods: Mechanical properties and handling characteristics (ISO 5833, DIN 53435), HPLC elution, antimicrobial effectiveness with proliferation assay (DIN 17025) and inhibition zone testing were investigated; Results: All tested Daptomycin concentrations fulfilled ISO and DIN mechanical strength. Dosage of 0.5. g added Daptomycin did not show any antimicrobial effectiveness in contrast to 1.0 g and1.5 g. Cement with 1.5 g Daptomycin was best in elution and effectiveness, showed good mechanical ISO strength, ISO doughing was a little longer sticky and setting was faster as Vancomycin containing reference cement; Conclusion: PMMA cement containing 0.5 g Gentamicin and 1.5 g Daptomycin could be a good alternative to the already established COPAL® G+V for PJI treatment of VRE.
ARTICLE | doi:10.20944/preprints202307.1770.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: structural valve degeneration; matrix damage; glutaraldehyde-fixed biomaterials; pericardium; immunogenicity; calcification; calcinosis-resistant biomaterials; heart valve bioprosthesis
Online: 26 July 2023 (07:20:56 CEST)
Pathological aseptic calcification is the most common form of structural valvular degeneration (SVD), leading to premature failure of heart valve bioprostheses (BHVs). The processing methods used to obtain GA-fixed pericardium-based biomaterials determine the hemodynamic characteristics and durability of BHVs. This article presents a comparative study of the effects of several processing methods on the degree of damage to the ECM of GA-fixed pericardium-based biomaterials as well as on their biostability, biocompatibility, and resistance to calcification. Based on the assumption that preservation of the native ECM structure will enable the creation of calcinosis-resistant materials, this study provides a soft biomimetic approach for the manufacture of GA-fixed biomaterials using gentle decellularization and washing methods. It has been shown that the use of soft methods for preimplantation processing of materials, ensuring maximum preservation of the intactness of the pericardial ECM, radically increases the resistance of biomaterials to calcification. The data obtained are of interest for the development of new calcinosis-resistant biomaterials for the manufacture of BHVs.
ARTICLE | doi:10.20944/preprints202311.0329.v1
Subject: Biology And Life Sciences, Virology Keywords: Bacteriophage; myovirus; Myroviridae; phage; phage therapy; lytic phage; virulent phage; carbapenem-resistant Enterobacteriaceae; antimicrobial resistance; AMR; alternative medicine
Online: 6 November 2023 (11:22:33 CET)
Escherichia coli causes several infections like intestinal diarrhea, urinary tract infections, and pneumonia, which are difficult to treat due to the emergence of antimicrobial resistance. The World Health Organisation (WHO) declared carbapenem-resistant E. coli a critical pathogen and called for the development of new antimicrobial agents. Phage therapy, a century-old technique, has been revitalised recently with many successful applications against multi-drug resistant infections. As such, phage therapy is considered one of the most effective alternatives or adjuvants to antibiotics and is also effective in treating multidrug-resistant (MDR) bacterial infections. However, few phages that can kill pathogenic E. coli strains from Southeast Asia have been studied at a molecular level, although the burden of MDR, particularly carbapenem resistance, is high in this region. In this study, three closely related obligately virulent Escherichia phages (øEc_Makalu_001, øEc_Makalu_002, and øEc_Makalu_003) that could infect uropathogenic E. coli were isolated from sewage samples and characterized using morphological as well as sequence-based analysis. Further, a comparative genomic and phylogenetic analysis was done to predict the functional genes and evolutionary relationships. Electron microscopy and genome-based classification revealed that all three phages belonged Krischvirus genus of Straboviridae family. One-step growth curve showed that the latent period of the phages ranged from 15-20 min, the outbreak period was about 50 min, and the burst size ranged between 74-127 PFU/bacterium. Moreover, the phages could tolerate a pH range of 6 to 9 and a temperature range of 25-37°C for up to 180 minutes without significant loss of phage viability. Spotting the purified phages in different clinical isolates showed a broad host-range of isolated Escherichia phages and could lyse up to 30% of the tested pathogenic clinical isolates, including an intra-genus isolate of Klebsiella pneumoniae. The genome organization of all three phages was almost identical and similar to T4-like phage with a full-length genome of ~163 kb. Around 284 coding sequences (CDS) were predicted in each phage, of which only 40% were functional with an average gene length of 951 bp. The coding density in all phages was approximately 95%, while the gene density was 1.73 gene/kbp. Putative lysin, holin, endolysin, and spanin genes were found in the genomes of all three phages, resembling that of T4-like phages implying their phylogenetic relatedness. Furthermore, various in silico sequence analysis tools confirmed that all three phages were strictly virulent with functional lysis modules but devoid of any known virulence or toxin genes, integron-associated genes and antimicrobial-resistance (AMR) genes. In summary, pre-clinical experimental analysis and exploration of genomic features suggest that all three phages may be suitable candidates for therapeutic applications against uropathogenic E. coli.
ARTICLE | doi:10.20944/preprints202311.0120.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Agrobacterium; Xenorhabdus; NR-AMP; T-DNA keyword; TI-plasmid; Intact/Cured/T-DNA Deleted; Sensitive/Resistant; EMA_PF2; HPLC
Online: 2 November 2023 (07:42:14 CET)
Keywords: Agrobacterium 1; Xenorhabdus 2; NR-AMP 3 T-DNA keyword 4; TI-plasmid 5; Intact/Cured/T-DNA Deleted 6 Sensitive/Resistant 7; EMA_PF2 8; HPLC 9
REVIEW | doi:10.20944/preprints202207.0393.v1
Subject: Medicine And Pharmacology, Urology And Nephrology Keywords: metastatic castration-resistant prostate cancer; cancer vaccines; immunotherapy; focal therapy; combination immunotherapy; tumor immune microenvironment; in vivo vaccination
Online: 26 July 2022 (08:01:20 CEST)
Due to slow progression and susceptibility to radical forms of treatment low-grade PC is associ-ated with high overall survival (OS). With the clinical progression of PC the therapy is getting more complex. The immunosuppressive tumor microenvironment (TME) makes PC a difficult target for most immunotherapeutics. Its general immune resistance is established by i.e. immune evasion through Treg cells, synthesis of immunosuppressive mediators, and defective expression of surface neoantigens. The success of sipuleucel-T in clinical trials initiated several other clinical studies that specifically target the immune escape of the tumor and eliminate the immunosuppres-sive properties of TME. In the settings of PC treatment, this can be commonly achieved with radi-ation therapy (RT). Also, focal therapies usually applied for localized PC, such as high-intensity focused ultrasound (HIFU) therapy, cryotherapy, photodynamic therapy (PDT), or irreversible electroporation (IRE) were shown to boost anti-cancer response. Nevertheless, the present guide-lines restrict their application to localized and low-grade PC. This review explains how RT and focal therapies enhance the immune response. We also provide data supporting the combination of RT and focal treatments with immune therapies.
ARTICLE | doi:10.20944/preprints202304.1195.v1
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: COVID-19 pandemic; antimicrobial resistance; infectious diseases consultation; multi-drug resistant bacteria; infection prevention and control group; antibiotic stewardship
Online: 29 April 2023 (03:23:00 CEST)
Introduction: The reduced implementation of surveillance programs and limited bedside infectious diseases consultations due to the pressure of COVID-19 pandemic in healthcare systems led to increased rates of irrational use of antimicrobials and incidence of infections by multidrug-resistant microorganisms. The aim of the present study is to evaluate the incidence of antimicrobial resistance and the management of bloodstream infections before and during COVID-19 pandemic at the University General Hospital of Alexandroupolis (Greece). Material-Methods: This is a retrospective study conducted from January 2018 to December 2022. Data were collected from the University Microbiology Laboratory per semester regarding the isolated strains of Gram positive and negative bacteria in blood cultures and respiratory samples in hospitalized patients in medical and surgical wards and in the Intensive Care Unit (ICU). Additionally, bloodstream infections with requested infectious diseases consultation were reported (n=400), determining whether these were carried out via telephone contact or at the patient's bedside. Demographic data, comorbidities, focus of infection, antimicrobial regimen, duration of treatment, length of hospitalization and clinical outcome were analysed. Results: A total of 4569 strains of Gram positive and negative bacteria were isolated. An increasing trend was reported compared to the pre-pandemic period in the incidence of resistant Gram-negative bacteria, particularly in ICUs. Prior antimicrobial use and the rate of hospital-acquired infections were increased significantly during the pandemic. In the pre-pandemic period 2018-2019, a total of 246 infectious diseases consultations were carried out, while during the period 2020-2022 154, with the percentage of telephone consultations 15% and 76% respectively. Detection of the source of infection and timely administration of appropriate antimicrobial agents were more frequently recorded before the pandemic and 28-day mortality was significantly reduced in cases with bedside consultations. Conclusion: Empowering of infectious diseases surveillance programs and committees, rational use of antimicrobials agents and bedside infectious diseases consultations are vital in order to reduce the impact of infections caused by multidrug-resistant strains.
ARTICLE | doi:10.20944/preprints202112.0234.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: submerged arc; heat resistant steel; square waveform welding; aggregate quality index; bay area; melting efficiency; process; model; process map
Online: 14 December 2021 (12:46:10 CET)
The demand for efficient processes through a comprehensive understanding and optimization of welding conditions continues to grow in the manufacturing industry. This study involves heat-resistant 2.25 Cr-1 Mo V-groove steel welding using the square-waveform alternating cur-rent. Experiments were conducted to build the relationship between input variables—such as current, frequency, electrode negativity ratio, and welding speed—and process performance, such as penetration, bay area, deposition rate, melting efficiency, percentage dilution, flux–wire ratio, and heat input. The process was analyzed in light of the defect-free high-deposition weld groove weld, the sensitivity to process parameters, and the optimization and development of the process map. The study proposes an innovative approach to reducing the cost and time of optimizing the one-pass-each-layer V-groove welding process using bead-on-plate welds. Square waveform welding creates a metallurgical notch in the form of a bay at the fusion boundary that can be minimized by selecting appropriate welding conditions. The square waveform submerged arc welding is more sensitive towards changes in current and welding speed than the frequency and electrode negativity ratio; however, the electrode negativity ratio and frequency are minor but helpful parameters to achieve optimal results. The proximity of the planned and experimental results to within 3% confirms the validity of the proposed approach. The investigation shows that 90% of the maximum deposition rate is possible for one-pass-each-layer V-groove welds within heat input and weld width constraints.
HYPOTHESIS | doi:10.20944/preprints202108.0531.v1
Subject: Business, Economics And Management, Accounting And Taxation Keywords: nature of stock rights; state-controlled firm; income smoothing; institutional investor; pressure-resistant institutional investor; pressure-sensitive institutional investor
Online: 28 August 2021 (15:07:13 CEST)
The purpose of this study is to examine the relationship between the institutional investors which can affect financial performance for corporate sustainability on the income smoothing. Therefore, this study focus on the connection between the nature of stock rights and income smoothing in China. For this study, hypotheses were established on the relationship each state-controlled companies, income smoothing, and information equilibrium of individual investors, and empirical analysis was conducted through related variables. The analysis results are summarized in three categories as follows. First, this research finds that state-controlled firms (CONTs) prefer income smoothing activities compared to non-state-controlled firms for the long-term sustainable development of firms using data from 2011 to 2019. Second, this study found out that Institutional investors support the behavior of CONTs to smooth their earnings because this behavior is seen as an attempt by CONTs to convey valuable private information to other investors. Third, we was able to discover that institutional investors' monitoring effect is predominantly driven by pressure-resistant institutional investors. This research complements the lack of empirical research on income smoothing and enable to give a guideline that the type of stock rights is a critical key determinant of participation in income smoothing activities for stable growth and sustainability in the future.
REVIEW | doi:10.20944/preprints201904.0083.v1
Subject: Biology And Life Sciences, Ecology, Evolution, Behavior And Systematics Keywords: toxin–antitoxin systems; toxin–antitoxin genetic module; sapronoses; resistant (dormant) cell form of bacteria; viable but nonculturable (VBNC) cell; persistence
Online: 8 April 2019 (10:49:35 CEST)
In interepidemic periods, a sapronoses typically employs a variety of mechanisms for maintaining viability of its causative agent in terrestrial parasitic systems, associated with different adaptive strategies utilized by its populations to survive. Unlike spore-forming bacteria, causative agents of sapronoses use resistant cell forms, which is a viable but nonculturable (VBNC) state, and persistence. Implementation of these strategies is conditioned by effects of various stress factors of the habitat and is characterized by decreased metabolism, alteration of the morphology and physiology of bacterial cell, and cessation of its replication. It is important that the resistant forms of cells retain virulence and, as favorable conditions come, turn back into the active vegetative form again. The discovery of the genetic modules of bacterial toxin–antitoxin systems in recent years has made it possible to identify a number of complicated regulatory molecular mechanisms responsible for maintaining the pathogenic potential of resistant forms of causative agents of natural-focus sapronoses in interepidemic periods.
ARTICLE | doi:10.20944/preprints202304.0699.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Conventional alfalfa; dormant variety; glyphosate resistant alfalfa; Medicago sativa; non-dormant variety; reduced lignin alfalfa; salinity; seed germination; seedling growth; temperature
Online: 21 April 2023 (08:59:50 CEST)
Seed germination and seedling growth represent two vulnerable stages in a plant life cycle and it is important to determine how they will be affected by environmental changes associated with climate change. This study examines the impact of salinity levels (0, 50, 100, and 150 mM) at each of three temperatures (15, 25, and 35˚C) on seed germination and radicle growth for three dormant and three non-dormant varieties of conventional, glyphosate resistant, or reduced lignin alfalfa. The genetic basis and phenotypic plasticity for seed germination and seedling growth in response to salinity and temperature were determined. Both traits were phenotypically plastic with respect to temperature and salinity. Seed germination was 87.0% ± 1.7 at 25˚C, 0mM (no salinity), but decreased to 33.9% ± 3.9 germination at 35˚C and 150mM. Radicle length went from 36.7 ± 1.5 mm after four days at 25˚C, 0mM, to 10.5 ± 0.7 mm at 35˚C, 150mM. The phenotypic response brought seed germination and radicle length away from their optimum, but we detected standing genetic variation for both seed germination and radicle length. Selection to increase both traits at high temperature and salinity would facilitate alfalfa establishment under climate change.
ARTICLE | doi:10.20944/preprints202108.0329.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: face shield; facial protective equipment; SARS-CoV-2; phi 6; MRSA; MRSE; polyethylene terephthalate; benzalkonium chloride; COVID-19; multidrug-resistant bacteria
Online: 16 August 2021 (11:38:49 CEST)
Transparent materials used for facial protection equipment provide protection against microbial infections caused by viruses and bacteria, including multidrug-resistant strains. However, transparent materials used for this type of application are made of materials that do not possess antimicrobial activity. They just avoid direct contact between the person and the biological agent. Therefore, healthy people can get infected through contact of the contaminated material surfaces and this equipment constitute an increasing source of infectious biological waste. Furthermore, infected people can transmit microbial infections easily because the protective equipment do not inactivate the microbial load generated while breathing, sneezing, or coughing. In this regard, the goal of this work consisted of fabricating a transparent face shield with intrinsic antimicrobial activity that could provide extra-protection against infectious agents and reduce the generation of infectious waste. Thus, a single-use transparent antimicrobial face shield composed of polyethylene terephthalate and an antimicrobial coating of benzalkonium chloride has been developed for the next generation of facial protective equipment. The antimicrobial coating was analyzed by atomic force microscopy and field emission scanning electron microscopy with elemental analysis. This is the first facial transparent protective material capable of inactivating enveloped viruses such as SARS-CoV-2 in less than one minute of contact, and the methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. Bacterial infections contribute to severe pneumonia associated with the SARS-CoV-2 infection, and their resistance to antibiotics is increasing. Our extra protective broad-spectrum antimicrobial composite material could also be applied for the fabrication of other facial protective tools such as such as goggles, helmets, plastic masks and space separation screens used for counters or vehicles. This low-cost technology would be very useful to combat the current COVID-19 pandemic and protect health care workers from multidrug-resistant infections in developed and underdeveloped countries.
ARTICLE | doi:10.20944/preprints202304.0610.v1
Subject: Engineering, Control And Systems Engineering Keywords: power equipment; structural and heat resistant steels; mechanical properties, structural-phase state, acoustic and magnetic characteristics, deformation localization zone, structural-mechanical criterion
Online: 20 April 2023 (05:37:01 CEST)
The use of acoustic and magnetic methods of non-destructive testing to detect zones of stable localization of deformation in order to assess and predict the performance of long-term equipment is of scientific and practical interest at present. A structural-mechanical criterion has been developed, that reflects the revealed relationships between the structural and substructural states, internal stress fields and stable localization of deformations with the characteristics of non-destructive tests in the metal of long-term equipment made of structural 0.2 С steel and heat-resistant 0,12C-1Cr-1Mo-1V steel. The values of the structural-mechanical criteria Ks.-m for structural 0.2 С steel and for heat-resistant 0,12C-1Cr-1Mo-1V steel, corresponding to the moment of stable localization of deformation, are established. At the same time, it is recommended to replace the checked equipment nodes due to the exhaustion of the resource. The proposed and justified approach to assessing and predicting the performance and residual life of long-term power equipment, based on the identified relationships between the structural and substructural states, internal stress fields and stable localization of deformations with the characteristics of non-destructive tests and the calculation of the structural-mechanical criterion, was applied at a number of power plants in the Kemerovo region – Kuzbass. A methodology has been developed for evaluating the residual life, based on the identification and use of relationships between structural and substructural states, internal stress fields and stable localization of deformations with the characteristics of non-destructive tests and the calculation of a structural-mechanical criterion.