ARTICLE | doi:10.20944/preprints202302.0072.v1
Subject: Biology, Animal Sciences & 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 & Pharmacology, Cardiology 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: Life Sciences, 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.
Subject: Medicine & Pharmacology, Allergology 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/preprints202103.0024.v1
Subject: Life Sciences, Biochemistry 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: 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.
CASE REPORT | doi:10.20944/preprints202007.0219.v1
Subject: Medicine & Pharmacology, Pediatrics 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/preprints201810.0293.v1
Subject: Medicine & Pharmacology, Other 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.
ARTICLE | doi:10.20944/preprints202104.0086.v1
Subject: Engineering, Electrical & 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/preprints202201.0131.v1
Subject: Medicine & Pharmacology, General Medical Research 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/preprints202111.0358.v1
Subject: Life Sciences, 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
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.
REVIEW | doi:10.20944/preprints202209.0037.v1
Subject: Biology, Animal Sciences & 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/preprints202209.0384.v1
Subject: Chemistry, 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 & Pharmacology, Other 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/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 & Pharmacology, Other 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: Life Sciences, 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 & Pharmacology, Pharmacology & 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/preprints202211.0314.v1
Subject: Life Sciences, 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: Life Sciences, 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 & Pharmacology, Oncology & 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/preprints202301.0540.v1
Subject: Life Sciences, 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 & Pharmacology, Psychiatry & Mental Health Studies 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, Anatomy & Morphology 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 & Pharmacology, Oncology & 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: Materials Science, Surfaces, Coatings & 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: Materials Science, Polymers & 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/preprints202202.0166.v1
Subject: Life Sciences, 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: Life Sciences, Biochemistry 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: Life Sciences, Biochemistry 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, Other 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/preprints202101.0524.v5
Subject: Physical Sciences, General & Theoretical 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, 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 & Pharmacology, Urology 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.
REVIEW | doi:10.20944/preprints201912.0179.v1
Subject: 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/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 & Pharmacology, Pathology & 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: 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/preprints202011.0065.v1
Subject: Life Sciences, Biochemistry 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.
REVIEW | doi:10.20944/preprints202207.0393.v1
Subject: Medicine & Pharmacology, Urology 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/preprints202112.0234.v1
Subject: Engineering, Industrial & 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: Social Sciences, Accounting 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, Ecology 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/preprints202108.0329.v1
Subject: Materials Science, Surfaces, Coatings & 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.
REVIEW | doi:10.20944/preprints202110.0016.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: prostate cancer; castrate-resistant growth; metastases; androgen receptor; glucocorticoid receptor; cytokines; transmembrane receptors; cell signaling; pharmacological targeting; neuroendocrine differentiation; lineage plasticity; prostate cancer stem cells
Online: 1 October 2021 (12:19:03 CEST)
Understanding of the molecular mechanisms of prostate cancer has led to development of therapeutic strategies targeting androgen receptor (AR). These androgen-receptor signaling inhibitors (ARSI) include androgen synthesis inhibitor- abiraterone and androgen receptor antagonists- enzalutamide, apalutamide, and darolutamide. Although these medications provide significant improvement in survival among men with prostate cancer, drug resistance develops in nearly all patients with time. This could be through androgen-dependent or androgen-independent mechanisms. Even weaker signals and non-canonical steroid ligands can activate AR in the presence of truncated AR-splice variants, AR overexpression, or activating mutations in AR. AR splice variant, AR-V7 is the most studied among these and is not targeted by available ARSIs. Non-androgen receptor dependent resistance mechanisms are mediated by activation of an alternative signaling pathway when AR is inhibited. DNA repair pathway, PI3K/AKT/mTOR pathway, BRAF-MAPK and Wnt signaling pathway and activation by glucocorticoid receptors can restore downstream signaling in prostate cancer by alternative proteins. Multiple clinical trials are underway exploring therapeutic strategies to overcome these resistance mechanisms.
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Neuroendocrine Neoplasms; NOTCH; cancer driven genes; mutational mechanism; germline mutations.; small cell lung carcinoma; pancreatic NET; small bowel NET; medullary thyroid carcinoma; malignant castration-resistant prostatic cells
Online: 23 July 2019 (10:34:50 CEST)
Neuroendocrine neoplasms (NENs) comprise a heterogeneous group of rare malignancies mainly originated from hormones secreting cells, which are widespread in human tissues. The identification of mutations in ATRX/DAXX genes in sporadic NENs, as well as the high burden of mutations scattered throughout MEN-1 gene in both sporadic and inherited syndromes, provided new insights into the molecular biology of tumour development. Other molecular mechanisms, such as the NOTCH signaling pathway, have shown to play an important role in the pathogenesis of NENs. NOTCH receptors are expressed on neuroendocrine cells and generally, act as tumour suppressor proteins, but in some contexts can function as oncogenes. The biological heterogeneity of NENs suggests that to fully understand the roles and the potential therapeutic implications of gene mutations and NOTCH signaling in NENs, a comprehensive analysis of genetic alterations, NOTCH expression patterns and their potential roles across all NEN subtypes is required.