Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: Surface soil moisture; Sentinel-1 SAR; Sentinel-2; Vegetation water content; Water cloud model; Support vector regression
Online: 2 June 2021 (15:22:42 CEST)
Surface soil moisture (SSM) is a significant factor affecting crop growth. This paper presents a method for retrieving SSM over wheat-covered areas using synergy dual-polarization C-band Sentinel-1 synthetic aperture radar and Sentinel-2 optical data. Firstly, a modified water cloud model (WCM) was proposed to remove the influence of vegetation from the backscattering coefficient of the radar data. The vegetation fraction was then introduced in this WCM, and the vegetation water content (VWC) was calculated using multiple linear regression model. Subsequently, the support vector regression technique was used to retrieve the SSM. This approach was validated using in-situ measurements of the wheat field in Hebi, in the north of Henan Province. The key findings of this study are as follows: (1) Based on vegetation indices obtained from Sentinel-2; the proposed VWC estimation model can effectively eliminate the influence of vegetation; (2) compared with vertical transmit and horizontal receive polarization, vertical transmit and vertical receive polarization is better for detecting changes in SSM at different growth stages of wheat; and, (3) the validation results indicated that the proposed approach, based on Sentinel-1 and Sentinel-2 data, successfully retrieved SSM in the study area.
ARTICLE | doi:10.20944/preprints202004.0466.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: COVID-19; coronavirus; ACE2; bioinformatics analysis; drug prediction
Online: 26 April 2020 (03:14:50 CEST)
Recently, the outbreak of coronavirus disease 2019 (COVID-19) is threatening human health globally. There is a dire need to find potential therapeutic agents. Angiotensin converting enzyme 2 (ACE2), as an entry receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is considered as potential therapeutic target in COVID-19 pandemic. Here, our bioinformatics analysis revealed that the biological function of ACE2 was correlated with regulation of blood pressure and mediation of SARS-CoV-2 entry into host cells. Ten ACE2 cooperative proteins were identified by using STRING with a high score. ACE2 expressed highly in the small intestine, testis, and kidney. The level of ACE2 expression in tumor tissues varies in different types of cancers compared with that in normal tissues. It was worth noting that the expression level of ACE2 in the tumor has no effect on patient survival. MiRNA hsa-miR-942-5p, and three transcription factors (TFs) including Signal transducer and activator of transcription 4 (STAT4), Estrogen related receptor α (ESRRA), and Signal transducer and activator of transcription 3 (STAT3) were selected as novel ACE2 regulators. Moreover, nine potential therapeutic drugs were predicted by two online databases. Thus, our research may expand the overall view of ACE2 in COVID-19 treatment.
ARTICLE | doi:10.20944/preprints201904.0066.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: Raman spectra; mixed pesticides; apple; correction method; rapid; real-time
Online: 5 April 2019 (15:17:24 CEST)
In the study, a new correction method was applied to reduce error during detection on mixed pesticide residue in apples by using Raman spectra. Combined with self-built pesticide residues detection system by Raman spectroscopy and the application of surface enhancement technology, rapid real-time qualitative and quantitative analysis of deltamethrin and acetamiprid residues in apples can be applied effectively. In quantitative analysis, compared with the intensity value of characteristic peaks of single pesticide with same concentration, the intensity value of characteristic peaks of the two pesticides decreased after mixing the pesticides, which interferes the results severely. By comparing the difference in the intensity of characteristic peaks of single and mixed pesticides, a correction method is proposed to eliminate the influence of pesticides mixture. Characteristic peak intensity values of gradient concentration pesticide from 10-1 g•kg-1 to 10-6 g•kg-1 and Lagrangian interpolation are applied in the correction method. And a smooth surface is applied to describe the correction ratio of characteristic peak intensity. Through detecting the characteristic peak intensity values of the mixed pesticide, correction ratio will be obtained. Then real values of the peak intensity of pesticides and the content of each component of the mixed pesticide will be acquired by the correction method. Correlation coefficient of model validation exceeds 0.88 generally and Root Mean Square Error also decreases obviously after correction, which proved the reliability of the method.
ARTICLE | doi:10.20944/preprints202311.1099.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: cathode material; SOFC; SrCoO3-d perovskite; neutron diffraction
Online: 17 November 2023 (08:57:37 CET)
Cathode materials based on SrCoO3- perovskite-type oxides hold great potential, given the huge oxygen permeability exhibited by the cubic phase of this oxide, which must be stabilized though suitable cationic substitutions. We present here two novel materials of the series Sr1-xYxCoO3- (x= 0.1, 0.2), prepared by solid state reactions. The crystalline structure was explored by neutron powder diffraction. At RT, we identified a subtle tetragonal superstructure, yet preserving the wanted framework of vertex-sharing CoO6 octahedra. A noteworthy result of the neutron analysis is the presence of conspicuous amounts of oxygen vacancies, ordered in layers and responsible for the formation of the mentioned superstructure. The stability was investigated by thermal analysis, using thermogravimetry (TGA). The electrical conductivity gave a maximum value of 800 °C of 122 S·cm–1. To determine the resistance associated with the oxygen reduction reaction (ORR), electrochemical impedance spectroscopy as a function of temperature was carried out, finding a value for the activation energy of Ea= 0.82 eV. This is a much lower value than that usually obtained for cathodes with a high catalytic activity for the oxygen reduction reaction. In single-cell tests, the materials generated a power density up to 0.25 Wcm−2 at 800ºC, using pure H2 as fuel. All these features make this perovskite a suitable candidate as cathode material in intermediate-temperature SOFCs
ARTICLE | doi:10.20944/preprints201807.0215.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: multivariate gaussian mixture model (MVGMM); multivariate linear regression; expectation-maximization imputation; WiFi localization; hidden markov model (HMM)
Online: 12 July 2018 (08:24:06 CEST)
The extensive deployment of wireless infrastructure provides a low-cost way to track mobile users in indoor environment. This paper demonstrates a prototype model of an accurate and reliable room location awareness system in a real public environment, where three typical problems arise. First, a massive number of access points (APs) can be sensed leading to a high-dimensional classification problem. Second, heterogeneous devices record different received signal strength (RSS) levels due to the variations in chip-set and antenna attenuation. Third, APs are not necessarily visible in every scanning cycle leading to missing data. This paper presents a probabilistic Wi-Fi fingerprinting method in a hidden Markov model (HMM) framework for mobile user tracking. Considering the spatial correlation of the signal strengths from multiple APs, a Multivariate Gaussian Mixture Model (MVGMM) is fitted to model the probability distribution of RSS measurements in each cell. Furthermore, the unseen property of invisible AP has been investigated in this research, and demonstrated the efficiency of differentiation between cells. The proposed system is able to achieve comparable localization performance. The filed test results present a reliable 97% localization room level accuracy of multiple mobile users in a real university campus WiFi network without any prior knowledge of the environment.
ARTICLE | doi:10.20944/preprints202308.0502.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: platelet linked particles; megakaryocyte; G protein coupled recepto
Online: 7 August 2023 (10:07:34 CEST)
In this study, we reported that novel single-chain fusion-proteins linked thromboxane A2 (TXA2) receptor (TP) to a selected G-protein α-subunit q (SC-TP-Gαq), or s (SC-TP-Gαs) could be stably expressed in megakaryocytes (MK). We tested the MK-released platelet-linked particles (PLPs) to be used as a vehicle to deliver the over-expressed SC-TP-Gαq), or s (SC-TP-Gαs) to regulate human platelet function. To understand how the single-chain TP-Gα fusion proteins could regulate opposite platelet activities by an identical ligand TXA2, we used dual-binding domains linked to different signaling pathways within a single polypeptide chain using a 3D structural model. The immature MKs were cultured and transfected with cDNAs constructed from structural models of the individual SC-TP-Gαq and SC-TP-Gαs, respectively. After transient expression was identified, the immature MKs stably expressing SC-TP-Gαq or SC-TP-Gαs (stable cell lines) were selected. The stable cell lines were induced into mature MKs which released PLPs. Western blot analysis confirmed that the released PLPs were carrying the recombinant SC-TP-Gαq or SC-TP-Gαs. Flow cytometry analysis showed the PLPs carrying SC-TP-Gαq were able to perform the activity by promoting platelet aggregation. In contrast, PLPs carrying SC-TP-Gαs reversed Gq to Gs signaling to inhibit platelet aggregation. This is the first time demonstrating that SC-TP-Gαq and SC-TP-Gαs were successfully overexpressed in MK cells and released as PLPs with proper folding. This bio-engineering led to the formation of two sets of biologically active PLP forms, which mediate calcium and cAMP signaling, respectively. As a result, these PLPs are able to bind to identical endogenous TXA2 with opposite activities, inhibiting and promoting platelet aggregation as required for therapeutic process.The results also demonstrated the nucleus-free PLPs could be used to deliver recombinant membrane-bound GPCRs to regulate cellular activity in general.
ARTICLE | doi:10.20944/preprints202306.0638.v1
Subject: Engineering, Transportation Science And Technology Keywords: Risk analysis; Fire hazards; Bayesian network; Ro-ro spaces
Online: 8 June 2023 (10:58:05 CEST)
This study probes the probabilistic features of major fire hazards in enclosed spaces to establish their importance to the occurrence of fires onboard ro-ro passenger ships and in turn to raise effective operational countermeasures. Distinct from the previous studies, the present research employs Bayesian Network (BN) analysis to determine the probabilities of fire hazards more effectively. The findings of the research include five critical basic events (BE) identified namely, vehicle engine fire (fuel system fault), vehicle electric fire (electrical equipment defect or short circuit), used car electrical fire, reefer units electrical fire (electrical appliances defects or short circuit), and cargo spontaneous combustion. Additionally, the risk of fire for lithium - ion battery powered vehicles is also highlighted in the process of BN analysis, which prompts the authors to propose preventive measures for mitigating the possibility of fire occurrence on this type of electric vehicles. It is hoped that these measures can be essential justifications for establishing relevant rules regarding carrying LIB vehicles in enclosed spaces on international level.
ARTICLE | doi:10.20944/preprints201805.0402.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: heterogeneous catalysis; transfer hydrogenation; biomass conversion; biofuels; catalytic materials
Online: 28 May 2018 (12:27:29 CEST)
Catalytic upgrading of bio-based platform molecules is one of promising approaches for biomass valorization. However, most solid catalysts are thermally and/or chemically unstable and difficult to prepare. In this study, a stable organic phosphonate-hafnium solid catalyst (PPOA-Hf) was synthesized, and acid-base bifunctional sites were found to play a cooperative role in the cascade transfer hydrogenation and cyclization of ethyl levulinate (EL) to γ-valerolactone (GVL). Under relatively mild reaction conditions of 160 ºC for 6 h, EL was completely converted to GVL in a good yield of 85%. The apparent activation energy was calculated to be 53 kJ/mol, which was lower than other solid catalysts for the same reaction. In addition, the PPOA-Hf solid catalyst did not significantly decrease its activity after five recycles, and no evident leaching of Hf was observed, indicating its high stability and potential practical application.
ARTICLE | doi:10.20944/preprints201710.0183.v1
Subject: Biology And Life Sciences, Ecology, Evolution, Behavior And Systematics Keywords: Arbuscular mycorrhiza; Chrysanthemum morifolium; N acquisition; Salt stress
Online: 30 October 2017 (15:32:49 CET)
The study aimed to investigate the effects of colonization with two arbuscular mycorrhizal (AM) fungi, Funneliformis mosseae , Diversispora versiformis , alone and in combination on the growth and nutrient acquisition of NaCl-stressed Chrysanthemum morifolium (Hangbaiju) plants in the greenhouse experiment. Mycorrhizal and non-mycorrhizal Hangbaiju plants were grown under different salinity levels imposed by 0, 50 and 200 mM NaCl for five months, following 6 weeks of non-saline pre-treatment. The results showed that root length, shoot and root dry weight, total dry weight, shoot and root N concentration were higher in mycorrhizal than in non-mycorrhizal plants under moderate saline conditions especially with D. versiformis colonization. As salinity increased, the mycorrhizal colonization, the mycorrhizal dependence (MD) decreased. Enhancement of tissue N acquisition is probably the main mechanism underlying salt tolerance in AM plants. It is suggested that the symbiotic associations between D. versiformis fungus and C. morifolium plants may be taken as a biotechnological practice in culture.
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: BiVO4; nanobelts; photocatalyst; reusability; stability
Online: 10 May 2019 (14:33:25 CEST)
BiVO4 powder was synthesized by a simple hydrothermal method. The nanobelts with well dispersed and uniform morphology were synthesized by controlling the temperature. The structure of BiVO4 powder was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The diameter of the nanobelts was about 50 nm. The structure and composition of the nanobelts were studied by X-ray diffraction (XRD), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). The absorption intensity of BiVO4 powder in UV-Vis region was compared by UV–vis diffuse reflectance spectroscopy. As a photocatalyst, BiVO4 nanobelts have good photocatalytic ability under visible light irradiation, which is very useful for the treatment of environmental wastewater. The synthesized nanobelts photocatalyst can be reused without destroying its structure. The reusability and chemical stability of photocatalysts are of great significance for practical application.
ARTICLE | doi:10.20944/preprints201709.0039.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: stable carbon isotope analysis; lipids; fatty acids; Cordyceps sinensis; the Qinghai-Tibetan Plateau
Online: 11 September 2017 (08:06:30 CEST)
Cordyceps sinensis is one rare medicinal fungus produced in the Qinghai-Tibetan Plateau. Its quality and price varies hugely with different habitat, and its numerous substitutes have sprung up in functional food markets. This paper aims to discriminate the geographic origin of wild C. sinensis and its substitutes via the element analyzer-isotope ratio mass spectrometry and gas chromatography-isotope ratio mass spectrometry. The δ13C values of major fatty acids in the lipids of Cordyceps sinensis are characterized unanimously by the variation relation C18:0 ﹤ C18:2 ≈ C16:0 ﹤ C18:1; while their fluctuation intervals are notably different between those of neutral and polar lipids. The comparative analysis of the δ13C ratios of major fatty acids in lipids of Cordyceps sinensis suggests that the δ13C patterns may be sensitive potential indicators to discriminate its geographical origin. The δ13C values of individual major fatty acids of lipids from the cultivated stromata of Cordyceps militaris (SCM), the fermented mycelia of Hirsurella sinensis (FMH) and Paecilomyces epiali (FMP) range from −31.2‰ to −29.7‰, −16.9‰ to −14.3‰, and −26.5‰ to −23.9‰, respectively. Their δ13C pattern of individual major fatty acids may be used as a potential indicator to discriminate the products of natural C. sinensis and its substitutes.
REVIEW | doi:10.20944/preprints202008.0155.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: temporomandibular joint disorders; arthrocentesis; TMJ; arthralgia; lavage
Online: 6 August 2020 (10:36:53 CEST)
The aim of this study was to assess the best timing to perform arthrocentesis in the management of temporomandibular disorders with regards to conservative treatment. A systematic search based on PRISMA guidelines, including a computer search with specific keywords, reference list search, and manual search was done. Relevant articles were selected after 3 search rounds for final review based on 6 predefined inclusion criteria, followed by a round of critical appraisal. Eleven publications, including 5 randomized controlled trials and 6 prospective clinical studies informed this review. The studies were divided into 3 groups based on the timing of arthrocentesis: 1). Arthrocentesis as the initial treatment, 2). Early arthrocentesis, and 3). Late arthrocentesis. Meta-analyses compared the efficacy of improvement in mouth opening and pain reduction in the 3 groups. The results were statistically significant and favoured early arthrocentesis, followed by late arthrocentesis in terms of both improvements in mouth opening and pain reduction. All 3 groups showed improvement in mouth opening and pain reduction. We conclude that early arthrocentesis may be able to produce the best clinical results, while arthrocentesis before attempting conservative treatment may produce less favourable outcomes.
ARTICLE | doi:10.20944/preprints202108.0243.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Early Psychosis; Cardiovascular Disease Risk; Quality of Life; Lifestyle Behaviours.
Online: 11 August 2021 (08:55:02 CEST)
Introduction: People with schizophrenia have poor cardiometabolic health, with elevated 10-year cardiovascular disease risk (CVD-R) scores and poor quality of life (QOL). There is lack of understanding of these issues in early psychosis. Aims: To quantify CVD-R in people with early psychosis and profile their obesity prevalence, lifestyle behaviours and QOL. Secondary aim was to explore associations between lifestyle behaviours/treatment characteristics and CVD-R/QOL. Method:Baseline data from 81 RCT participants were used to profile cardiometabolic health risks (QRISK®3, BMI and waist circumference). Participants self-reported lifestyle behaviours and QOL. Relationships between modifiable treatment/lifestyle factors and QOL/CVD-R were explored using bivariate analyses. Results: Participants’ relative risk for CVD over 10 years was 1.93 times higher than healthy counterparts; 39% also had an obese BMI and physical QOL was poor. No significant associations were observed between CVD-R or QOL with treatment characteristics and lifestyle factors. Discussion: Despite positive lifestyle behaviours, participants had elevated CVD-R scores and poor physical health related QOL. Quantifying CVD-R with QRISK®3 may highlight the need for health promotion interventions. Implications for practice: Mental health professionals should be alert to elevated cardiometabolic health risks in early psychosis, particularly as these can occur in the context of relatively healthy lifestyle behaviours.
ARTICLE | doi:10.20944/preprints202202.0232.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Small RNA sequencing; miRNAs; Target prediction; Chemosensory-associated genes; Apolygus lucorum
Online: 18 February 2022 (10:01:58 CET)
MicroRNAs (miRNAs) are a class of small non-coding RNAs, which function as regulators of gene expression and contribute in numerous physiological processes. However, little is known referring to miRNAs function in insect chemosensation. In the current study, nine small RNA libraries were constructed and sequenced from the antennae of nymphs, adult males and females of Apolygus lucorum. In total, 399 miRNAs were identified including 275 known and 124 novel miRNAs. Known miRNAs were classified into 71 families, amongst which, 23 families were insect-specific. Expression profile analysis showed that miR-7-5p_1 was the most abundant miRNAs in the antennae of A. lucorum. Altogether, 69708 target genes related to biogenesis, membrane and binding activities were predicted for 399 miRNAs. Particularly, 15 miRNAs were found to target 16 olfactory genes. These miRNAs could be involved in regulation of olfactory-associated genes ex-pression. Comparing the antennae of nymphs, adult males and females, 94 miRNAs were found to be differentially expressed. The expression levels of some differentially expressed miRNAs measured by qPCR were consistent with sequencing results. This study provides a global miRNAs transcriptome in the antennae of A. lucorum and valuable information for further investigation on miRNA-mRNA interactions, especially the functions of miRNAs in regulating chemosensation.
ARTICLE | doi:10.20944/preprints202011.0204.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: hypoxia; cisplatin sensitivity; mitochondrial fission; ROS; head and neck squamous cell carcinoma
Online: 5 November 2020 (10:02:19 CET)
Chemotherapy treatment based on Cisplatin (CDDP) is established as the drug of choice for head and neck squamous cell carcinoma (HNSCC). Malignant tumors respond to microenvironment alteration through a dynamic balance of mitochondrial fission and fusion. HNSCC is known to have hypoxic conditions, yet the effects and underlying mechanisms of hypoxia on chemosensitivity and mitochondrial dynamics remain unclear. We found that hypoxia promoted mitochondrial fission and CDDP sensitivity in HNSCC cells. Importantly, Mff was shown to be correlated with chemosensitivity in clinical samples of HNSCC that underwent a hypoxic condition. Hypoxia-inducible factor 1 α-subunit (HIF-1α) dramatically increased Mff transcriptional expression and directly bound to Mff. Hypoxia enhanced the release of reactive oxygen species (ROS) and upregulated the expression of Mff via HIF-1α in HNSCC cells. ROS depletion in HNSCC cells attenuated HIF-1α, Mff expression, and mitochondrial fission. Moreover, a knockdown of Mff suppressed hypoxia-induced mitochondrial fission and decreased CDDP chemosensitivity in vivo and in vitro. Our findings revealed that the hypoxia-induced release of ROS promoted mitochondrial fission and CDDP chemosensitivity via the regulation of HIF-1α/Mff in HNSCC cells, indicating that Mff may serve as a new biomarker to predict neoadjuvant chemosensitivity in HNSCC patients
BRIEF REPORT | doi:10.20944/preprints202003.0091.v1
Subject: Biology And Life Sciences, Virology Keywords: SARS-CoV-2; coronavirus; angiotensin converting enzyme 2 (ACE2); receptor utilization; phylogenetic analysis.
Online: 5 March 2020 (12:12:38 CET)
SARS-CoV-2, the newly identified human coronavirus causing severe pneumonia epidemic, was probably originated from Chinese horseshoe bats. However, direct transmission of the virus from bats to humans is unlikely due to lack of direct contact, implying the existence of unknown intermediate hosts. Angiotensin converting enzyme 2 (ACE2) is the receptor of SARS-CoV-2, but only ACE2s of certain species can be utilized by SARS-CoV-2. Here, we evaluated and ranked the receptor-utilizing capability of ACE2s from various species by phylogenetic clustering and sequence alignment with the currently known ACE2s utilized by SARS-CoV-2, predicting potential intermediate hosts of SARS-CoV-2.
REVIEW | doi:10.20944/preprints202205.0158.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: Parkinson’s disease; Epigenetic targets; Histone deacetylases; Inhibitors; PROTACs
Online: 12 May 2022 (05:41:21 CEST)
Parkinson’s disease (PD) is a chronic progressive neurodegenerative disease that increasingly become a global threat for the elder people's health and life. Although there are some drugs in clinic for treating PD, these treatments only can alleviate the symptoms of PD patients but fail in curative therapies. Therefore, seeking other potential mechanisms to develop more effective treatments that can modify the course of PD is still highly desirable. In the last two decades, histone deacetylases as an important group of epigenetic targets in drug discovery have attracted much attention. This review is focused on the current knowledge about histone deacetylases involved in PD pathophysiology and their inhibitors used in PD study. Further perspectives related to small molecules that can inhibit or degrade histone deacetylases to treat PD are also discussed.
ARTICLE | doi:10.20944/preprints201808.0061.v1
Subject: Medicine And Pharmacology, Dietetics And Nutrition Keywords: Asian Americans; child; diet; eating; feeding behavior; sodium, dietary
Online: 3 August 2018 (05:05:05 CEST)
Obesity has been identified as an emerging health concern for Chinese American children; however, very little is known about diets in Asian American children. The objective of our paper was to describe the dietary intakes of urban Chinese American schoolchildren using a state-of-the-art approach for dietary assessment. Data for this analysis come from the Food Journal Project 2017, a pilot and feasibility study conducted by a multi-sector collaboration. Children aged 8-12 (n=83) completed two dietary assessments using a food diary from January-June 2017. Children were then interviewed using the food diary as a guide and dietary data were entered into the online ASA24 system by study staff. Chinese American children were identified using surname, and were compared to non-Chinese peers with respect to nutrient intake and the Healthy Eating Index 2010 (HEI-2010). Chinese American children consumed more sodium dense diets, more protein, and less sugar compared to non-Chinese children. With regards to the HEI-2010, Chinese American children had less favorable whole grains and sodium scores; and more favorable seafood protein and empty calories scores compared to non-Chinese children. Sodium reduction and increasing whole grain intakes may be warranted in this group, but should be verified with additional studies.
ARTICLE | doi:10.20944/preprints202202.0041.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: Laser scanning instrument; 3D scanner calibrator; surface reflectance; measurement accuracy
Online: 2 February 2022 (15:57:04 CET)
Abstract: The calibrator is one of the most important factors in the calibration of various laser 3D scanning instruments. The requirements for diffuse reflection surface are specially emphasized in many national standards. In this study, the spherical calibrator and plane calibrator compara-tive measurement experiments were carried out. The black ceramic standard sphere, white ce-ramic standard sphere, metal standard sphere, metal standard plane and white ceramic standard plane were used to test the laser 3D scanner. In the spherical calibrators comparative measure-ment experiments, the results indicated that the RMS of the white ceramic spherical calibrator with reflectance about 60% is 10 times that of the metal spherical calibrator with the reflectance of about 15%, and the RMS of the black ceramic spherical calibrator with reflectance of about 11% is of the same order as the metal spherical calibrator. In the plane calibrators comparative measurement experiments, the RMS of flatness measurement is 0.077 mm for metal plane cali-brator with reflectance of 15%, and 2.915 mm for ceramic plane calibrator with reflectance of 60%. The results show that when the optimal measurement distance and incident angle are selected, the reflectance of the calibrator has a great effect on the measurement results, regardless of the outlines or profiles. Based on the experiments, it is recommended to use the spherical calibrator or the standard plane with reflectance of around 18% as the standard, which can obtain the rea-sonable results. In addition, it is necessary to clearly provide the material category and surface reflectance information of the standard when calibrating the scanner according to the measure-ment standard.
ARTICLE | doi:10.20944/preprints202305.0993.v1
Subject: Public Health And Healthcare, Other Keywords: Sepsis-induced cardiomyopathy; Gene sequencing; Whole transcriptome profiles; Septic animal models; Cecal ligation and puncture; Lipopolysaccharide
Online: 15 May 2023 (07:36:05 CEST)
Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, with septic cardiomyopathy being a common and severe complication. Despite its significant clinical impact, the molecular mechanisms underlying sepsis-induced cardiomyopathy (SICM) remain incompletely understood. In this study, we performed a comparative analysis of whole transcriptome profiles in two widely used mouse models of septic cardiomyopathy, the cecal ligation and puncture (CLP) model and the lipopolysaccharide (LPS) model. Our aim was to identify key genes and pathways involved in the development of septic cardiomyopathy and to evaluate the similarities and differences between the two models. Our findings suggested that 1) both methods can induce septic heart dysfunction within 24 hours; 2) distinct whole transcriptome expression profiles are revealed; 3) potentially different pathways are involved in causing heart failure in sepsis. The comprehensive comparison provides valuable insights into the molecular basis of septic cardiomyopathy and contributes to the ongoing search for effective treatment strategies, triggered by different factors for SICM.
ARTICLE | doi:10.20944/preprints202012.0289.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: remdesivir; perturbation of nucleotide pools; inhibition of RNA and DNA synthesis; CTP synthase
Online: 11 December 2020 (15:57:14 CET)
Remdesivir (RDV) has garnered much hope for its moderate anti-COVID-19 effects, but its limited amelioration of survival in hospitalized patient causes a huge controversy over the applicability of RDV to COVID-19 treatment. Developing strategies to improve its antivirus efficacy is urgently required. As anticipated, RDV exhibits similar behavior with other nucleotide analogs to disrupt the metabolism of natural endogenous ribonucleotides (RNs) and deoxyribonucleotides (dRNs). Alterations in endogenous RNs and dRNs play a critical role in virus replication as well as other key cellular functions. Thus elucidation of the disturbances of RDV on RNs and dRNs could help to understand its exact mechanism of action. Here, the metabolic profiling determined by liquid chromatography–mass spectrometry method showed a general increase in the abundance of nucleotides and a more than 2-fold increase for specific nucleotides. However, the variation of pyrimidine ribonucleotides was relative slight or even contrary, resulting in obvious imbalance between purine and pyrimidine ribonucleotides, which implied the obstacle of RDV to pyrimidine synthesis and could further block the transcription and replication of viral RNA. Additionally, the extreme disequilibrium between cytidine triphosphate (CTP) and cytidine monophosphate might result from the inhibition of CTP synthase and provide a metabolic target for the treatment of COVID-19 infection. Since nucleotides metabolism pathways are vulnerable to nucleotide analogues and are liable to be the regulation targets, it is promising to enhance the efficacy of RDV through co-administration with CTP synthase inhibitors or de novo pyrimidine synthesis inhibitors to exacerbate the imbalance of nucleotide pools.
ARTICLE | doi:10.20944/preprints202205.0184.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: amyloid precursor protein; photothrombotic stroke; ischemia; alpha-secretase; beta-secretase; gamma-secretase
Online: 13 May 2022 (08:39:09 CEST)
Photothrombotic stroke (PTS) stimulates the level of N- and C-terminal fragments of Amyloid precursor protein (APP) growth in the cytoplasm of ischemic penumbra cells not earlier but at 24 hours. Here we have shown that APP fragments are visualized in thin unmyelinated fibers of neurons, in containing mitochondria large fibers and in synapses but absent in the nuclei. At 24 hours after PTS, some elements of the destroyed tissue accumulated a significant amount of APP protein. The level of ADAM10 α-secretase decreased on the first day after PTS in the rat brain cortex and ADAM-10 co-localized with the lipid raft marker caveolin-1. PTS caused no changes in the level of β-secretase BACE1 either on the first day after PTS or in the early recovery period. The expression of proteins of the γ-secretase complex: presenilin-1 and nicastrin increased in astrocytes, but not in penumbra neurons after PTS. The β-secretase inhibitor LY2886721 did not affect the infarct size of the mouse cerebral cortex and the level of apoptosis of cells in the perifocal region after PTS. Whereas the inhibitor of γ-secretase DAPT reduced the expression of glial fibrillary acidic protein (GFAP) in astrocytes, prevented the growth of apoptosis of mouse cerebral cortex cells reducing the infarct volume on the 7th and 14th days after PTS. DAPT may be considered as a drug for stroke therapy.
ARTICLE | doi:10.20944/preprints201804.0033.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: cordycepin; adenosine A1 receptor; prolactin; anti-obesity
Online: 3 April 2018 (07:53:24 CEST)
Cordycepin is an extract from the insect fungus Cordyceps. militaris, which is a traditional medicine with various biological function. In previous studies, cordycepin had been reported with excellent anti-obesity effect, but the mechanism is unclear. A large quantity of evidences showed that prolactin plays an important part in body weight regulation, hyperprolactinemia can promote appetite and accelerate fat deposition. In this study, we explored the molecular mechanism of the anti-obesity effect of cordycepin by reducing prolactin release via an adenosine A1 receptor. In vivo, obese rats model was induced by high fat diet for 5 weeks, the serum and liver lipids coupling with serum prolactin were reduced by treatment of cordycepin, the results suggested that cordycepin is a potential drug for therapying obesity which could be related with prolactin. In vitro, cordycepin could inhibit prolactin secretion in GH3 cells via upregulating the expression of adenosine A1 receptor, the inhibition effect could be blocked by an antagonist of adenosine receptor A1 DPDPX, prolactin induced the upregulation of lipogenesis genes PRLR, and P-JAK2 in 3T3-L1 cells. Intriguingly, cordycepin would down-regulate the expression of prolactin receptor (PRLR). Thus, we concluded that cordycepin modulate body weight by reducing prolactin release via an adenosine A1 receptor.
COMMUNICATION | doi:10.20944/preprints201701.0037.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: 4-pyrones; diynones; water; transition-metal-free
Online: 9 January 2017 (04:46:22 CET)
Transition-metal-free synthesis of 4-pyrones via TfOH-promoted nucleophilic addition/cyclization of diynones and water has been developed. This transformation is simple, atom economical and environmentally benign, providing rapid and efficient access to substituted 4-pyrones.