REVIEW | doi:10.20944/preprints202004.0203.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; SARS-CoV-2; masks; pandemic
Online: 12 April 2020 (17:41:10 CEST)
The science around the use of masks by the general public to impede COVID-19 transmission is advancing rapidly. Policymakers need guidance on how masks should be used by the general population to combat the COVID-19 pandemic. Here, we synthesize the relevant literature to inform multiple areas: 1) transmission characteristics of COVID-19, 2) filtering characteristics and efficacy of masks, 3) estimated population impacts of widespread community mask use, and 4) sociological considerations for policies concerning mask-wearing. A primary route of transmission of COVID-19 is likely via small respiratory droplets, and is known to be transmissible from presymptomatic and asymptomatic individuals. Reducing disease spread requires two things: first, limit contacts of infected individuals via physical distancing and contact tracing with appropriate quarantine, and second, reduce the transmission probability per contact by wearing masks in public, among other measures. The preponderance of evidence indicates that mask wearing reduces the transmissibility per contact by reducing transmission of infected droplets in both laboratory and clinical contexts. Public mask wearing is most effective at stopping spread of the virus when compliance is high. The decreased transmissibility could substantially reduce the death toll and economic impact while the cost of the intervention is low. Thus we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.
Fri, 13 March 2020
ARTICLE | doi:10.20944/preprints202003.0226.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: COVID-2019; Mpro; 6LU7; medicinal plant compounds; docking
Online: 13 March 2020 (03:19:02 CET)
COVID-19, a new strain of coronavirus (CoV), was identified in Wuhan, China, in 2019. No specific therapies are available and investigations regarding COVID-19 treatment are lacking. Liu et al. (2020) successfully crystallised the COVID-19 main protease (Mpro), which is a potential drug target. The present study aimed to assess bioactive compounds found in medicinal plants as potential COVID-19 Mpro inhibitors, using a molecular docking study. Molecular docking was performed using Autodock 4.2, with the Lamarckian Genetic Algorithm, to analyse the probability of docking. COVID-19 Mpro was docked with several compounds, and docking was analysed by Autodock 4.2, Pymol version 18.104.22.168 Edu, and Biovia Discovery Studio 4.5. Nelfinavir and lopinavir were used as standards for comparison. The binding energies obtained from the docking of 6LU7 with native ligand, nelfinavir, lopinavir, kaempferol, quercetin, luteolin-7-glucoside, demethoxycurcumin, naringenin, apigenin-7-glucoside, oleuropein, curcumin, catechin, epicatechin-gallate, zingerol, gingerol, and allicin were -8.37, -10.72, -9.41, -8.58, -8.47, -8.17, -7.99, -7.89, -7.83, -7.31, -7.05, -7.24, -6.67, -5.40, -5.38, and -4.03 kcal/mol, respectively. Therefore, nelfinavir and lopinavir may represent potential treatment options, and kaempferol, quercetin, luteolin-7-glucoside, demethoxycurcumin, naringenin, apigenin-7-glucoside, oleuropein, curcumin, catechin, and epicatechin-gallate appeared to have the best potential to act as COVID-19 Mpro inhibitors. However, further research is necessary to investigate their potential medicinal use.
Sun, 19 April 2020
ARTICLE | doi:10.20944/preprints202004.0315.v1
Subject: Life Sciences, Molecular Biology Keywords: COVID-19; SARS-CoV2; ACE2 receptor; medical cannabis; CBD
Online: 19 April 2020 (02:45:50 CEST)
With the rapidly growing pandemic of COVID-19 caused by the new and challenging to treat zoonotic SARS-CoV2 coronavirus, there is an urgent need for new therapies and prevention strategies that can help curtail disease spread and reduce mortality. Inhibition of viral entry and thereby spread constitute plausible therapeutic avenues. Similar to other respiratory pathogens, SARS-CoV2 is transmitted through respiratory droplets, with potential for aerosol and contact spread. It uses receptor-mediated entry into the human host via angiotensin-converting enzyme II (ACE2) that is expressed in lung tissue, as well as oral and nasal mucosa, kidney, testes, and the gastrointestinal tract. Modulation of ACE2 levels in these gateway tissues may prove a plausible strategy for decreasing disease susceptibility. Cannabis sativa, especially one high in the anti-inflammatory cannabinoid cannabidiol (CBD), has been proposed to modulate gene expression and inflammation and harbour anti-cancer and anti-inflammatory properties. Working under the Health Canada research license, we have developed over 800 new Cannabis sativa lines and extracts and hypothesized that high-CBD C. sativa extracts may be used to modulate ACE2 expression in COVID-19 target tissues. Screening C. sativa extracts using artificial human 3D models of oral, airway, and intestinal tissues, we identified 13 high CBD C. sativa extracts that modulate ACE2 gene expression and ACE2 protein levels. Our initial data suggest that some C. sativa extract down-regulate serine protease TMPRSS2, another critical protein required for SARS-CoV2 entry into host cells. While our most effective extracts require further large-scale validation, our study is crucial for the future analysis of the effects of medical cannabis on COVID-19. The extracts of our most successful and novel high CBD C. sativa lines, pending further investigation, may become a useful and safe addition to the treatment of COVID-19 as an adjunct therapy. They can be used to develop easy-to-use preventative treatments in the form of mouthwash and throat gargle products for both clinical and at-home use. Such products ought to be tested for their potential to decrease viral entry via the oral mucosa. Given the current dire and rapidly evolving epidemiological situation, every possible therapeutic opportunity and avenue must be considered.
Fri, 3 July 2020
ARTICLE | doi:10.20944/preprints202007.0025.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: SARS-CoV-2; COVID-19; outpatients; treatment; zinc; hydroxychloroquine; azithromycin
Online: 3 July 2020 (08:52:22 CEST)
Objective: To describe outcomes of patients with coronavirus disease 2019 (COVID-19) in the outpatient setting after early treatment with zinc, low dose hydroxychloroquine, and azithromycin (the triple therapy) dependent on risk stratification. Design: Retrospective case series study. Setting: General practice. Participants: 141 COVID-19 patients with laboratory confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in the year 2020. Main Outcome Measures: Risk-stratified treatment decision, rate of hospitalization and all-cause death. Results: Of 335 positively PCR-tested COVID-19 patients, 127 were treated with the triple therapy. 104 of 127 met the defined risk stratification criteria and were included in the analysis. In addition, 37 treated and eligible patients who were confirmed by IgG tests were included in the treatment group (total N=141). 208 of the 335 patients did not meet the risk stratification criteria and were not treated. After 4 days (median, IQR 3-6, available for N=66/141) of onset of symptoms, 141 patients (median age 58 years, IQR 40-67; 73% male) got a prescription for the triple therapy for 5 days. Independent public reference data from 377 confirmed COVID-19 patients of the same community were used as untreated control. 4 of 141 treated patients (2.8%) were hospitalized, which was significantly less (p<0.001) compared with 58 of 377 untreated patients (15.4%) (odds ratio 0.16, 95% CI 0.06-0.5). Therefore, the odds of hospitalization of treated patients were 84% less than in the untreated group. One patient (0.7%) died in the treatment group versus 13 patients (3.5%) in the untreated group (odds ratio 0.2, 95% CI 0.03-1.5; p=0.16). There were no cardiac side effects. Conclusions: Risk stratification-based treatment of COVID-19 outpatients as early as possible after symptom onset with the used triple therapy, including the combination of zinc with low dose hydroxychloroquine, was associated with significantly less hospitalizations and 5 times less all-cause deaths.
Tue, 18 February 2020
ARTICLE | doi:10.20944/preprints202002.0258.v1
Subject: Life Sciences, Genetics Keywords: SARS-CoV-2; cell-entry receptor; ACE2 expression; The Cancer Genome Atlas; susceptibility; demographic factors; race
Online: 18 February 2020 (06:40:01 CET)
The recurrent coronavirus outbreaks in China (SARS-CoV and its relative, SARS-CoV-2) raise the possibility that Asians are more susceptible to coronavirus. Here, we test this possibility with the lung expression of ACE2, which encodes the cell-entry receptor of both SARS-CoV and SARS-CoV-2. We show that ACE2 expression is not affected during tumorigenesis, suggesting that the transcriptome data from the more than 1000 lung cancer samples in The Cancer Genome Atlas (TCGA) can be used to study ACE2 expression among people without cancer. The expression of ACE2 increases with age, but is not associated with sex. Asians show a similar ACE2 expression to other races. Furthermore, the frequencies of ACE2 alleles in Asians are not significantly deviated from those in other races. These observations indicate that individuals of all races need the same level of personal protection against SARS-CoV-2.
Wed, 5 February 2020
ARTICLE | doi:10.20944/preprints202002.0051.v1
Subject: Life Sciences, Microbiology Keywords: Wuhan 2019-nCov; ACE2; expression; susceptibility; race; age; gender; smoking
Online: 5 February 2020 (02:56:53 CET)
In current severe global emergency situation of 2019-nCov outbreak, it is imperative to identify vulnerable and susceptible groups for effective protection and care. Recently, studies found that 2019-nCov and SARS-nCov share the same receptor, ACE2. In this study, we analyzed four large-scale datasets of normal lung tissue to investigate the disparities related to race, age, gender and smoking status in ACE2 gene expression. No significant disparities in ACE2 gene expression were found between racial groups (Asian vs Caucasian), age groups (>60 vs <60) or gender groups (male vs female). However, we observed significantly higher ACE2 gene expression in smoker samples compared to non-smoker samples. This indicates the smokers may be more susceptible to 2019-nCov and thus smoking history should be considered in identifying susceptible population and standardizing treatment regimen.
Fri, 24 August 2018
REVIEW | doi:10.20944/preprints201808.0433.v1
Subject: Engineering, General Engineering Keywords: fermentation; bioreactor; heat transfer; mass transfer
Online: 24 August 2018 (11:34:14 CEST)
Fermenter is a vessel that maintains optimum environment for the development of significant microorganism used in large scale fermentation process and the commercial production of products like Alcoholic beverages, Enzymes, Antibiotics, Organic acids etc. The fermenter aims to produce biological product like vaccines and hormones, it is necessary to monitor and control the different parameters like external and internal mass transfer, heat transfer, fluid velocity, shear stress, agitation speed, aeration rate, cooling rate or heating intensity, and the feeding rate, nutrients, base or acid valve. Fermentation in the fermenter are accomplished in several configuration and these simple configurations are batch, fed-batch and continuous fermentation process. Fermentation process is carried out in small or large size fermenter depending on product quantity. The selection of the suitable process depends on the fermentation kinetics, type of microorganism used and process economic aspects. Improved modelling tools, reactor operation and reactor design in bioreactor is because of mass transfer behavior and it is important for reaction rate maximizing, throughput rates optimization and cost minimizing. The fermenter design, fermentation process, types of the fermenter that are used in industries and heat and mass transfer in fermenter is discussed.
Sat, 22 October 2016
REVIEW | doi:10.20944/preprints201610.0095.v1
Subject: Engineering, Other Keywords: aerofoil; CFD; lift and drag force; pressure and velocity contour
Online: 22 October 2016 (11:08:56 CEST)
NACA 0015 and NACA 4415 aerofoil are most common four digits and broadly used aerodynamic shape. Both of the shapes are extensively used for various kind of applications including turbine blade, aircraft wing and so on. NACA 0015 is symmetrical and NACA 4415 is unsymmetrical in shape. Consequently, they have big one-of-a-kind in aerodynamic traits at the side of widespread differences of their utility and performance. Both of them undergo the same fluid principle while applied in any fluid medium giving dissimilar outcomes in aerodynamics behavior. On this work, experimental and numerical investigation of each NACA 0015 and NACA 4415 is done to decide their performance. For this purpose, aerofoil section is tested for a prevalence range attack of angle (AOA). The study addresses the performance of NACA 0015 and NACA 4415 and evaluates the dynamics of flow separation, lift, drag, pressure and velocity contour and so on. This additionally enables to layout new optimistic aerofoil, which is critical to enhance the efficiency and performance of an aircraft in terms of lift enhancement and drag reduction.
Tue, 2 August 2016
ARTICLE | doi:10.20944/preprints201608.0008.v1
Subject: Engineering, Energy & Fuel Technology Keywords: horizontal axis tidal turbine; Computational Fluid Dynamics; mesh independency; NACA 0018
Online: 2 August 2016 (04:45:13 CEST)
This paper numerically investigates a 3D mesh independency study of a straight blade horizontal axis tidal turbine modelled using Computational Fluid Dynamics (CFD). The solution was produced by employing two turbulence models, the standard k-ε model and Shear Stress Transport (SST) in ANSYS CFX. Three parameters were investigated: mesh resolution, turbulence model, and power coefficient in the initial CFD, analysis. It was found that the mesh resolution and the turbulence model affect the power coefficient results. The power coefficients obtained from the standard k-ε model are 15% to 20% lower than the accuracy of the SST model. It can also be demonstrated that the torque coefficient increases with the increasing Tip Speed Ratio (TSR), but drops drastically after TSR = 5 and k-ε model failing to capture the non-linearity in the torque coefficient with the increasing TSR.
Thu, 12 March 2020
ARTICLE | doi:10.20944/preprints202003.0214.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: SARS-Cov-2; Citrus sp.; Galangal; Curcuma sp.; Sappan wood
Online: 12 March 2020 (13:59:40 CET)
COVID-19 pandemic is a serious problem in the world today. The SARS-CoV-2 virus that causes COVID-19 has important proteins used for its infection and development, namely the protease and spike glycoprotein. The RBD (Receptor Binding Domain) of spike glycoprotein (RBD-S) can bind to the ACE2 (Angiotensin Converting Enzyme-2) receptor at the protease domain (PD) (PD-ACE2) of the host cell, thereby leading to a viral infection. This study aims to reveal the potential of compounds contained in Curcuma sp., Citrus sp., Alpinia galanga, and Caesalpinia sappan as anti SARS-CoV-2 through its binding to 3 protein receptors. The study was conducted by molecular docking using the MOE 2010 program (licensed from Faculty of Pharmacy UGM, Indonesia). The selected protein targets are RBD-S (PDB ID:6LXT), PD-ACE2 (PDB ID: 6VW1), and SARS-CoV-2 protease (PDB ID:6LU7). The affinities of bonds formed is represented as a docking score. The results show that hesperidin, one of the compounds in Citrus sp., has the lowest docking score for all three protein receptors representing the highest affinity to bind the receptors. Moreover, all of the citrus flavonoids possess good affinity to the respected receptors as well as curcumin, brazilin, and galangin, indicating that those compounds perform inhibitory potential for the viral infection and replication. In general, the results of this study indicate that Citrus sp. exhibit the best potential as an inhibitor to the development of the SARS-CoV-2, followed by galangal, sappan wood, and Curcuma sp. that can be consumed in daily life as prophylaxis of COVID-19.
Thu, 30 January 2020
Subject: Medicine & Pharmacology, Other Keywords: 2019-nCov; Baicalin; Scutellarin; Hesperetin; Nicotianamine; Glycyrrhizin
Online: 30 January 2020 (03:06:07 CET)
2019-nCoV, a novel coronavirus, caused the pneumonia outbreak in China and continue to expand. The host receptor for 2019-nCoV Angiotensin-converting enzyme 2 (ACE2), which is the same as the host receptor of SARS-CoV. Targeting ACE2 holds the promise for preventing 2019-nCoV infection. Chinese Medicine herbs could be a valuable pool for identifying active compounds for treating infection of 2019-nCoV. In this study, we summarize several active compounds including baicalin, Scutellarin, Hesperetin, Nicotianamine and glycyrrhizin that could have potential anti-2019-nCoV effects, and we conduct molecular docking to predict their capacity for binding ACE2, which may subsequently prevent the 2019-nCoV infection. We propose that these selected compounds worth further investigation for preventing 2019-nCoV.
Wed, 13 May 2020
REVIEW | doi:10.20944/preprints202004.0203.v2
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; SARS-CoV-2; masks; pandemic
Online: 13 May 2020 (13:16:04 CEST)
The science around the use of masks by the general public to impede COVID-19 transmission is advancing rapidly. Policymakers need guidance on how masks should be used by the general population to combat the COVID-19 pandemic. Here,we develop an analytical framework to examine an overlooked aspect of mask usage: masks as source-control targeting egress from the wearer with benefits at the population-level, rather than as PPE used for ingress control for health-care workers with focus on individual outcomes. We consider and synthesize the relevant literature to inform multiple areas: 1) transmission characteristics of COVID-19, 2) filtering characteristics and efficacy of masks, 3) estimated population impacts of widespread community mask use, and 4) sociological considerations for policies concerning mask-wearing. A primary route of transmission of COVID-19 is likely via respiratory droplets, and is known to be transmissible from presymptomatic and asymptomatic individuals. Reducing disease spread requires two things: first, limit contacts of infected individuals via physical distancing and other measures, and second, reduce the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces the transmissibility per contact by reducing transmission of infected droplets in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. The decreased transmissibility could substantially reduce the death toll and economic impact while the cost of the intervention is low. Given the current shortages of medical masks we recommend the adoption of public cloth mask wearing, as an effective form of source control for now, in conjunction with existing hygiene, distancing, and contact tracing strategies. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.
Sun, 26 November 2017
ARTICLE | doi:10.20944/preprints201711.0166.v1
Subject: Engineering, Civil Engineering Keywords: high-rise buildings; architecture; structural solutions; interaction; SWOT analysis
Online: 26 November 2017 (12:45:01 CET)
The article reveals distinctive features of the interaction between architectural and structural solutions for the design of tall buildings as well as spotlights the most distinctive cases of expression. In the contemporary world, interaction is turning into the antithesis of the formerly dominant utilitarian attitude and standardization of tall buildings architectural solutions. Meanwhile, the search for rational structural solutions leads to new possibilities of architectural expression. This necessitates the transformation of a structural solution and its adaptation to the need of a modern architect to be exceptional and noticed. Interaction covers the current as well as retrospective and perspective periods. SWOT analysis was used by the authors of the article to assess the interaction between architectural and structural solutions in tall buildings design, select the most important criteria that could be used searching for rational architectural and structural solutions in future by applying multi-criteria decision making methods.
Tue, 17 March 2020
REVIEW | doi:10.20944/preprints202003.0275.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: Antimalarial; Chemoprophylaxis; Chloroquine; Coronavirus; COVID-19; Global Health; Hydroxychloroquine; Public Health; SARS-CoV-2; Virus
Online: 17 March 2020 (09:17:53 CET)
There is a long trail of research studies testing the in vitro and in vivo efficacy of chloroquine and its derivatives in treating and preventing infection by various coronavirus species. More recent findings have highlighted the possibility of treating patients infected with the 2019 novel coronavirus, SARS-CoV-2. This review describes the mechanism of coronavirus infection, the mechanism of action of chloroquine, and summarizes the available literature highlighting the efficacy of chloroquine as an anti-coronavirus agent. These findings should encourage the wider scientific community to conduct thorough research on the possible efficacy of chloroquine and its derivatives in treating and preventing SARS-CoV-2 infection.
Thu, 12 March 2020
Online: 12 March 2020 (03:15:15 CET)
The COVID19 coronavirus SARS-CoV2 spreading in Wuhan and now worldwide has been shown to use angiotensin-converting enzyme 2 ACE2 as its host cell receptor, like the severe acute respiratory syndrome coronavirus (SARS-CoV). Epidemiology studies found different sex and age groups have different susceptibility to infection, and very skewed severity and mortality of the virus infection, with male, old age, and comorbidity being the most inflicted. Here by analyzing GTEx and other public data in 30 tissues across thousands of individuals, we found significantly higher expression in Asian females compared to males and other ethnic groups, an age dependent ACE2 expression decrease and a highly significant decrease in type II diabetic patients. Consistently, the most significant expression quantitative loci (eQTLs) contributing to high ACE2 expression are close to 100% in East Asians, >30% higher than other ethnic groups. Together with the shockingly common enrichment of viral infection pathways among ACE2 anti-expressed genes, binding of virus infection-related transcription factors at ACE2 regulatory regions, the repression of ACE2 expression by inflammatory cytokines and by type 2 diabetes, and the induction by estrogen and androgen (both decrease with age) established a negative correlation between ACE2 expression and CovID19 fatality at both population and molecular levels. Our results will be instrumental when designing potential prevention and treatment strategies for ACE2 binding coronaviruses in general.
Sun, 15 March 2020
REVIEW | doi:10.20944/preprints202003.0235.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: ascorbic acid; cahtelicidin; coronavirus; COVID-19; cytokine storm; influenza, pneumonia; prevention; respiratory tract infection; UVB; vitamin C; Vitamn D; solar radiation; treatment; observational; trial
Online: 15 March 2020 (01:47:19 CET)
Low vitamin D status in winter permits viral epidemics. During winter, people who do not take vitamin D supplements are likely to have low serum 25-hydroxyvitamin D [25(OH)D] concentrations. Vitamin D can reduce the risk of viral epidemics and pandemics in several ways. First, higher 25(OH)D concentrations reduce the risk of many chronic diseases, including cancers, cardiovascular disease, chronic respiratory tract infections (RTIs), diabetes mellitus, and hypertension. Patients with chronic diseases have significantly higher risk of death from RTIs than otherwise healthy people. Second, vitamin D reduces risk of RTIs through three mechanisms: maintaining tight junctions, killing enveloped viruses through induction of cathelicidin and defensins, and reducing production of proinflammatory cytokines by the innate immune system, thereby reducing the risk of a cytokine storm leading to pneumonia. Observational and supplementation trials have reported higher 25(OH)D concentrations associated with reduced risk of dengue, hepatitis, herpesvirus, hepatitis B and C viruses, human immunodeficiency virus, influenza, respiratory syncytial virus infections, and pneumonia. Results of a community field trial reported herein indicated that 25(OH)D concentrations above 50 ng/ml (125 nmol/l) vs. <20 ng/ml were associated with a 27% reduction in influenza-like illnesses. From the available evidence, we hypothesize that raising serum 25(OH)D concentrations through vitamin D supplementation could reduce the incidence, severity, and risk of death from influenza, pneumonia, and the current COVID-19 epidemic.
Tue, 31 March 2020
ARTICLE | doi:10.20944/preprints202003.0444.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: COVID-19; SARS-CoV-2; coronavirus; novel coronavirus; 3D printing; N95; respirator; mask
Online: 31 March 2020 (04:44:06 CEST)
The 2019 Novel Coronavirus (COVID-19) has caused an acute reduction in world supplies of personal protective equipment (PPE) due to increased demand. To combat the impending shortage of equipment including N95 masks, the George Washington University Hospital (GWUH) developed a 3D printed reusable N95 comparable respirator that can be used with multiple filtration units. We evaluated several candidate prototype respirator models, 3D printer filaments, and filtration units detailed here. Our most recent working model was based on a respirator found on an open source maker website and was developed with PLA (printer filament), a removable cap, a removable filtration unit consisting of two layers of MERV 16 sandwiched between MERV 13, and removable elastic bands to secure the mask. Our candidate mask passed our own suction test protocol to evaluate leakage and passed a qualitative Bitrix N95 fit test at employee health at GWUH. Further efforts are directed at improving the current model for seal against face, comfort, and sizing. The 3D model is available upon request and in the supplement of this paper. We welcome collaboration with other institutions and suggest other facilities consider mask fit for their own population when exploring this concept.
Fri, 3 April 2020
HYPOTHESIS | doi:10.20944/preprints202004.0023.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; bradykinin; ACE2; pulmonary angioedema; ARDS; icatibant
Online: 3 April 2020 (04:13:43 CEST)
Most striking observations in COVID-19 patients are the hints on pulmonary edema (also seen on CT scans as ground glass opacities), dry cough, fluid restrictions to prevent more severe hypoxia, the huge PEEP that is needed while lungs are compliant, and the fact that anti-inflammatory therapies are not powerful enough to counter the severity of the disease. We propose that the severity of the disease and many deaths are due to a local vascular problem due to activation of B1 receptors on endothelial cells in the lungs. SARS-CoV-2 enters the cell via ACE2, a cell membrane bound molecule with enzymatic activity that next to its role in RAS is needed to inactivate des-Arg9 bradykinin, the potent ligand of the bradykinin receptor type 1 (B1). In contrast to bradykinin receptor 2 (B2), the B1 receptor on endothelial cells is upregulated by proinflammatory cytokines. Without ACE2 acting as a guardian to inactivate the ligands of B1, the lung environment is prone for local vascular leakage leading to angioedema. Angioedema is likely a feature already early in disease, and might explain the typical CT scans and the feeling of people that they drown. In some patients, this is followed by a clinical worsening of disease around day 9 due to the formation antibodies directed against the spike (S)-antigen of the corona-virus that binds to ACE2 that could contribute to disease by enhancement of local immune cell influx and proinflammatory cytokines leading to damage. In parallel, inflammation induces more B1 expression, and possibly via antibody-dependent enhancement of viral infection leading to continued ACE2 dysfunction in the lung because of persistence of the virus. In this viewpoint we propose that a bradykinin-dependent local lung angioedema via B1 and B2 receptors is an important feature of COVID-19, resulting in a very high number of ICU admissions. We propose that blocking the B1 and B2 receptors might have an ameliorating effect on disease caused by COVID-19. This kinin-dependent pulmonary edema is resistant to corticosteroids or adrenaline and should be targeted as long as the virus is present. In addition, this pathway might indirectly be responsive to anti-inflammatory agents or neutralizing strategies for the anti-S-antibody induced effects, but by itself is likely to be insufficient to reverse all the pulmonary edema. Moreover, we provide a suggestion of how to ventilate in the ICU in the context of this hypothesis.
Fri, 8 July 2016
ARTICLE | doi:10.20944/preprints201607.0013.v1
Subject: Social Sciences, Finance Keywords: capital structure, total debt ratio, profitability, return on assets, firms, Ethiopia
Online: 8 July 2016 (10:42:31 CEST)
This study was aimed to investigate the effect of capital structure on firms’ profitability with special emphasis on Ethiopian Large Private Manufacturing Firms using panel data of five consecutive years (2006/07-2010/11G.C). The secondary data sources (audited financial statements) have been collected from the randomly selected thirty three large private manufacturing firms in Ethiopia. Linear regression model has been employed to analyze the relationship between firms’ profitability and capital structure. Specifically, Random-effect Generalized Least Square of panel data regression model has been selected to empirically test the literature driven hypotheses. Finally, the findings of this study revealed that a significant positive relationship between firms’ profitability and total debt ratio which indicate firm’s capital structure.
Wed, 8 April 2020
HYPOTHESIS | doi:10.20944/preprints202004.0124.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; SARS-CoV-2; Therapy; Chloroquine; Hydroxychloroquine; Zinc
Online: 8 April 2020 (10:54:33 CEST)
Currently, drug repurposing is an alternative to novel drug development for the treatment of COVID-19 patients. The antimalarial drug chloroquine (CQ) and its metabolite hydroxychloroquine (HCQ) are currently being tested in several clinical studies as potential candidates to limit SARS-CoV-2-mediated morbidity and mortality. CQ and HCQ (CQ/HCQ) inhibit pH-dependent steps of SARS-CoV-2 replication by increasing pH in intracellular vesicles and interfere with virus particle delivery into host cells. Besides direct antiviral effects, CQ/HCQ specifically target extracellular zinc to intracellular lysosomes where it interferes with RNA-dependent RNA polymerase activity and coronavirus replication. As zinc deficiency frequently occurs in elderly patients and in those with cardiovascular disease, chronic pulmonary disease, or diabetes, we hypothesize that CQ/HCQ plus zinc supplementation may be more effective in reducing COVID-19 morbidity and mortality than CQ or HCQ in monotherapy. Therefore, CQ/HCQ in combination with zinc should be considered as additional study arm for COVID-19 clinical trials.
Thu, 23 August 2018
ARTICLE | doi:10.20944/preprints201808.0422.v1
Subject: Social Sciences, Organizational Economics & Management Keywords: Logistics; Logistical Centralization; Logistical Decentralization
Online: 23 August 2018 (23:37:23 CEST)
In the area of health, namely hospitals, we can agree that the intrinsic need to have multidisciplinary teams, highly specialized and indispensable resources leads us to a degree of complexity that requires, daily, the best performance, not running away from the logistics area to the rule. The centralization of resources, namely distribution warehouses, emerges as a challenge and possible solution for health institutions to respond in the best possible way to their main purpose: to put the right material in the right place at the right price in the right time space. As regards the advantages of this type of organization, there are several authors who argues that the need for human resources training, ease of coordination and the use of economies of scale are the main advantage. As far as the disadvantages are concerned, there is no special agreement on them, there are disparate factors from author to author, such as: routine, centralization, objectives or operation costs.
Mon, 11 March 2019
ARTICLE | doi:10.20944/preprints201903.0131.v1
Subject: Engineering, Energy & Fuel Technology Keywords: energy consumption; prediction; machine learning models; deep learning models; 21 artificial intelligence (AI); computational intelligence (CI); forecasting; soft computing (SC)
Online: 11 March 2019 (10:09:33 CET)
Machine learning (ML) methods has recently contributed very well in the advancement of the prediction models used for energy consumption. Such models highly improve the accuracy, robustness, and precision and the generalization ability of the conventional time series forecasting tools. This article reviews the state of the art of machine learning models used in the general application of energy consumption. Through a novel search and taxonomy the most relevant literature in the field are classified according to the ML modeling technique, energy type, perdition type, and the application area. A comprehensive review of the literature identifies the major ML methods, their application and a discussion on the evaluation of their effectiveness in energy consumption prediction. This paper further makes a conclusion on the trend and the effectiveness of the ML models. As the result, this research reports an outstanding rise in the accuracy and an ever increasing performance of the prediction technologies using the novel hybrid and ensemble prediction models.
Fri, 24 April 2020
Subject: Medicine & Pharmacology, Allergology Keywords: antibodies; COVID-19; glycans; immunoglobulin M; SARS-CoV-2; pneumonia; prediction; protection
Online: 24 April 2020 (10:25:27 CEST)
The natural history of COVID-19 caused by SARS-CoV-2 is extremely variable, ranging from asymptomatic infection, to pneumonia, and to complications eventually fatal. We propose here the first model, explaining how the outcome of first, crucial 10-15 days after infection, hangs on the balance between the cumulative dose of viral exposure and the efficacy of the local innate immune response (natural IgA and IgM antibodies, MBL). If SARS-CoV-2 runs the blockade of this innate immunity and spreads from the upper airways to the alveoli in the early phases of the infections, it can replicate with no local resistance, causing pneumonia and releasing high amounts of antigens. The delayed and strong adaptive immune response (high affinity IgM and IgG antibodies) that follows, causes severe inflammation and triggers mediator cascades (complement, coagulation, and cytokine storm) leading to complications often requiring intensive therapy and being, in some patients, fatal. Strenuous exercise and high flow air in the incubation days and early stages of COVID-19, facilitates direct penetration of the virus to the lower airways and the alveoli, without impacting on the airway’s mucosae covered by neutralizing antibodies. This allows the virus to bypass the efficient immune barrier of the upper airways mucosa in young and healthy athletes. In conclusion, whether the virus or the adaptative immune response reach the lungs first, is a crucial factor deciding the fate of the patient. This “quantitative and time-sequence dependent” model has several implications for prevention, diagnosis, and therapy of COVID-19.
Mon, 23 March 2020
ARTICLE | doi:10.20944/preprints202003.0333.v1
Online: 23 March 2020 (04:30:47 CET)
COVID-19, a rapidly spreading new strain of coronavirus, has affected more than 150 countries and received worldwide attention. The lack of efficacious drugs or vaccines against SARS-CoV-2 has further worsened the situation. Thus, there is an urgent need to boost up research for the development of effective therapeutics and affordable diagnostic against COVID-19. The crystallized form of SARS-CoV-2 main protease (Mpro) was demonstrated by a Chinese researcher Liu et al. (2020) which is a novel therapeutic drug target. This study was conducted to evaluate the efficacy of medicinal plant-based bioactive compounds against COVID-19 Mpro by molecular docking study. Molecular docking investigations were performed by using Molegro Virtual Docker 7 to analyze the inhibition probability of these compounds against COVID-19. COVID-19 Mpro was docked with 80 flavonoid compounds and the binding energies were obtained from the docking of (PDB ID: 6LU7: Resolution 2.16 Å) with the native ligand. According to obtained results, hesperidin, rutin, diosmin, apiin, diacetylcurcumin, (E)-1-(2-Hydroxy-4-methoxyphenyl)-3-[3-[(E)-3-(2-hydroxy-4- methoxyphenyl)-3-oxoprop-1-enyl]phenyl]prop-2-en-1-one, and beta,beta'-(4-Methoxy-1,3- phenylene)bis(2'-hydroxy-4',6'-dimethoxyacrylophenone have been found as more effective on COVID-19 than nelfinavir. So, this study will pave a way for doing advanced experimental research to evaluate the real medicinal potential of these compounds to cure COVID-19.
Tue, 5 May 2020
REVIEW | doi:10.20944/preprints202005.0070.v1
Subject: Life Sciences, Virology Keywords: Covid; covid-19; sars-cov-2; temperature; heat; body temperature; air temperature; viral decay; viral stability; transmission; severity
Online: 5 May 2020 (10:47:18 CEST)
Air temperature and body temperature may influence COVID-19 disease severity and transmission rates. In vitro data indicate that SARS-CoV-2 loses infectivity at normal core body temperature (37°C); however, small reductions in temperature proximate to 37°C may result in substantially increased viral stability. If these results are representative of viral decay rates in vivo, then cooler temperatures in the body may enable more rapid viral growth. Breathing cool air—even as warm as 25°C—cools upper respiratory tract (URT) surfaces to several degrees below body temperature, and these lower temperatures may make the URT exceptionally conducive to SARS-CoV-2 replication. Increased URT viral load may enable more effective transmission. Additionally, because SARS-CoV-2 infection may frequently begin in the URT before spreading through the body, an increased rate of viral replication in the URT early in the disease course may result in more rapid progression of disease, potentially causing more severe adverse outcomes. Core body temperature may also be a factor in disease severity, as lower core body temperatures may enable more rapid viral growth. The significance of air temperature and body temperature to disease severity and transmission rates may inform preventative measures and post-exposure prophylaxis treatments for COVID-19.
Fri, 20 October 2017
ARTICLE | doi:10.20944/preprints201710.0138.v1
Subject: Arts & Humanities, Religious Studies Keywords: preservation; environment; quran; issues; Malaysia
Online: 20 October 2017 (10:11:16 CEST)
Currently, various issues on environment have been discussed, whether the importance, destruction or ways to prevent the destruction of the environment. This paper will explore the issue from the conventional viewpoint as well as from the Islamic perspective. Destruction of the environment in recent times has worsened due to the uncontrolled exploitation of natural resources by human beings in order to generate profits. In view of the increasing technological development in Malaysia presently, this matter should not have occurred because the citizens intellectual abilities can be considered advanced. In other words, these people should be able to weigh between positive and negative consequences of voraciously exploiting natural resources. However, the greed that engulfs some of these people has obscured their view from grasping the future consequences of their acts. Based on the Islamic perspective in which the Quran is the ultimate reference, destruction of the environment can actually be prevented if every individual is aware of his or her trustworthiness or responsibility as His caliphate in this universe. Nevertheless, is there any specific verse in the Quran which explains about preservation of the environment? Can lessons from the Quran provide solutions to the environmental crises in Malaysia? This study provides explanations to the questions based on literature surveys and content analyses. By interpreting some selected verses that relate to preservation of the environment, findings from the discussions have identified that the Quranic verses are valuable resources for the sustainability of the environment.
Tue, 25 September 2018
ARTICLE | doi:10.20944/preprints201809.0484.v1
Subject: Behavioral Sciences, General Psychology Keywords: Bestiality; Colombia; sexual behavior; sexuality; Zoophilia
Online: 25 September 2018 (11:49:12 CEST)
Introduction: Sex with animals is a male practice with a social acceptance in many areas of the Colombian Atlantic coast; however, this behavior has been little studied. The aim of this study was to characterize the practice of sex with animals in a group of men living in Cordoba department, Colombia. Methods: descriptive quantitative study was made. Forty-seven adults were interviewed. The information was collected through a survey which asked about sociodemographic aspects, characteristics and beliefs around the behavior. Results: Total participants knew about the practice, 68,1% stated to have had it and they said it happened between the ages of 7 and 30 years old, for an average time of seven years gap; 65,6% had it in presence of friends and relatives. 87,6% said the practice feels really good at the first time; 35,6% stated it was a beneficial practice and 37,5% said they would like their sons to experience it. Conclusion: Having sex with animals is a social accepted behavior and it is thought to be positive since it helps the correct psychosexual development and it prevents other behaviors, not culturally accepted, such as drug use or homosexuality.
Fri, 21 April 2017
REVIEW | doi:10.20944/preprints201704.0137.v1
Subject: Chemistry, Chemical Engineering Keywords: process simulation; kinetic modelling; ammonia; methanol; bioethanol; steam reforming; ethylene
Online: 21 April 2017 (10:00:46 CEST)
Process simulation represents an important tool for plant design and optimisation, either applied to well established or to newly developed processes. Suitable thermodynamic packages should be selected in order to properly describe the behaviour of reactors and unit operations and to precisely define phase equilibria. Moreover, a detailed and representative kinetic scheme should be available to predict correctly the dependence of the process on its main variables. This review points out some models and methods for kinetic analysis specifically applied to the simulation of catalytic processes, as a basis for process design and optimisation. Attention is paid also to microkinetic modelling and to the methods based on first principles, to elucidate mechanisms and calculate thermodynamic and kinetic parameters. Different case histories support the discussion. At first, we have selected two basic examples from the industrial chemistry practice, e.g. ammonia and methanol synthesis, which may be described through a relatively simple reaction pathway. Then, a more complex reaction network is deeply discussed to define the conversion of bioethanol into syngas/hydrogen or into building blocks, such as ethylene.
Wed, 10 May 2017
REVIEW | doi:10.20944/preprints201705.0090.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Electric Vehicle; internal combustion engine; greenhouse gas; optimization techniques; Battery Electric Vehicle (BEV); Hybrid Electric Vehicle (HEV); Plug-in Hybrid Electric Vehicle (PHEV); Fuel Cell Electric Vehicle (FCEV).
Online: 10 May 2017 (17:44:51 CEST)
Electric vehicles (EV) are getting more commonplace in the transportation sector in recent times. As the present trend suggests, this mode of transport is likely to replace the internal combustion engine (ICE) vehicles in near future. Each of the main EV components has a number of technologies that are currently in use or can become prominent in the future. EVs can cause significant impacts on the environment, power system, and other related sectors. The present power system can face huge instabilities with enough EV penetration; but with proper management and coordination, EVs can be turned into a major contributor to the successful implementation of smart grid. There are possibilities of immense environmental benefits as well, as the EVs can extensively reduce the greenhouse gas emission from the transportation sector. However, there are some major obstacles for EVs to overcome before replacing the ICE vehicles totally. This paper is focused on reviewing all the useful data available on EV configurations, energy sources, motors, charging techniques, optimization techniques, impacts, trends, and possible directions of future developments. Its objective is to provide an overall picture of the current EV technology and ways of future development to assist in future researches in this sector.
Tue, 21 August 2018
REVIEW | doi:10.20944/preprints201808.0379.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Climate change, Developing countries, Environmental change, Forest, Population growth
Online: 21 August 2018 (14:00:04 CEST)
This review paper is intended to exhibit the interplays between environmental change and rapid population growth in developing countries. In the course of discussion, the impacts of rapidly population growing on the environment have been discussed, and evidence, from various parts of the world have been traced. Studies on the impacts of population pressure on environment have been critically reviewed. It is revealed that all across the developing countries, farm size is shrinking as farmers continue to subdivide holdings among their children. In countries such as Malawi, Rwanda, Ethiopia, Haiti, Nepal and Bangladesh, population growth rates are high, and the non-farm sector is still in its early stages of development. Demographic pressure, land scarcity, and land fragmentation drive greater rural vulnerability and poverty, marked by decreased food security, inadequate response to such natural disasters such as drought or pest infestations, weakened resilience to shocks, and poor health. It is not just the supply of food, fodder, and fuel wood but the resource base itself and the lives that depend upon it are being affected. The evidences pinpoints that man through his non-sustainable production and consumption patterns, is placed at the heart of environmental changes. However, contradictory view, and practices are also in place that the population growth has positive impacts environmental restoration and improvements, while other evidences show insignificant effect of population on the environment. This contradicting scenario puts scholars in argument, and still need further research. Hence, it would be a blind generalization to draw conclusion from this relationship alone, rather, another factor that acts beyond population pressure must also be considered to justify the impact of population on environmental changes.
Fri, 14 February 2020
ARTICLE | doi:10.20944/preprints202002.0179.v1
Online: 14 February 2020 (02:34:55 CET)
Ongoing outbreak of pneumonia caused by novel coronavirus (2019-nCoV) began in December 2019 in Wuhan, China, and the number of new patients continues to increase. On the contrary to ongoing outbreak in China, however, there are limited secondary outbreaks caused by exported case outside the country. We here conducted simulations to estimate the impact of potential secondary outbreaks at a community outside China. Simulations using stochastic SEIR model was conducted, assuming one patient was imported to a community. Among 45 possible scenarios we prepared, the worst scenario resulted in total number of persons recovered or removed to be 997 (95% CrI 990-1,000) at day 100 and maximum number of symptomatic infectious patients per day of 335 (95% CrI 232-478). Calculated mean basic reproductive number (R0) was 6.5 (Interquartile range, IQR 5.6-7.2). However, with good case scenarios with different parameter led to no secondary case. Altering parameters, especially time to hospital visit could change the impact of secondary outbreak. With this multiple scenarios with different parameters, healthcare professionals might be able to prepare for this viral infection better.
Sat, 25 April 2020
ARTICLE | doi:10.20944/preprints202004.0458.v1
Online: 25 April 2020 (10:31:39 CEST)
The COVID-19 has caused gigantic negative effects on populace wellbeing, society, education, and the economy in Bangladesh. The aim is to deliver a comprehensive overview of the observed and the possible impacts that could appear in the coming days. The study is based on secondary information. During the early period, due to a lack of accurate facts about the case affected and death tension up-and-down among the nations. The total number of confirmed cases is increasing following geometric patterns in Bangladesh. Dairy farmers, vegetable producers, pharmaceuticals, poultry farmers are in deep crisis due to lower prices. Also, the pandemic has seriously affected educational systems, banking, FDI, ready-made garments, remittances, etc Finally, it is not possible to mitigate the effects of pandemic individually but the integrated effort from the state authority as well as concern people of all sectors need to come forward.
Tue, 16 May 2017
ARTICLE | doi:10.20944/preprints201705.0123.v1
Subject: Mathematics & Computer Science, General & Theoretical Computer Science Keywords: Mobile device threats; mobile device malware; reverse proxy server; cyber security; android security; ios security; abuse of local area network; DNS spoofing; DNS hijacking
Online: 16 May 2017 (13:23:18 CEST)
Mobile devices have become tools we spend our free time where we carry them with us every moment, they allow us to interact with the environment, we immortalize the moment when necessary. These devices which we spend most of our daily life become very common in recent years and even there are unique business areas emerged. It was announced that the number of people using smartphones is over than 2.5 billion in the first quarter of 2016. As people become more addicted to mobile technology, they become the target of malevolent people. A huge increase in the number of mobile malware is observed as the number of the users increase. Billions of users at risk day by day due to the development of the methods. We have addressed the recent methods used and the types of malware that target mobile devices in our study. We have mentioned the proxy server and reverse proxy server operation logic. We discuss the method of turning mobile devices into reverse proxy servers, risks involved and protection methods.
Mon, 13 April 2020
REVIEW | doi:10.20944/preprints202004.0204.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: Covid-19; coronavirus; cardiovascular disease; thrombosis; hypertension; endothelial dysfunction
Online: 13 April 2020 (02:23:33 CEST)
The symptoms most commonly reported by patients affected by coronavirus disease 2019 (COVID-19) include cough, fever, and shortness of breath. However, other major events usually observed in COVID-19 patients (e.g. high blood pressure, thrombosis, pulmonary embolism) seem to suggest that the virus is targeting the endothelium, one of the largest organs in the human body. Herein, we report both clinical and preclinical evidence supporting the hypothesis that the endothelium is a key target organ of COVID-19.
Mon, 17 February 2020
BRIEF REPORT | doi:10.20944/preprints202002.0242.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: COVID-19; molecular docking; HIV protease inhibitor; nucleotide analogues
Online: 17 February 2020 (07:28:31 CET)
The outbreak of novel coronavirus (COVID-19) infections occurring in 2019 is in dire need of finding potential therapeutic agents. In this study, we used molecular docking strategies to repurpose HIV protease inhibitors and nucleotide analogues for COVID-19. The evaluation was made on docking scores calculated by AutoDock Vina and RosettaCommons. Preliminary results suggested that Indinavir and Remdesivir have the best docking scores and the comparison of the docking sites of these two drugs shows a near perfect dock in the overlap region of the protein pocket. However, the active sites inferred from the proteins of SARS coronavirus are not compatible with the docking site of COVID-19, which may give rise to concern in the efficacy of drugs.
Tue, 5 May 2020
ARTICLE | doi:10.20944/preprints202005.0057.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; treatment; drug; survival; antiviral; hydroxychloroquine
Online: 5 May 2020 (03:32:22 CEST)
Background: There is no treatment proven effective against COVID-19. Several drugs with in vitro potential against SARS-CoV-2 virus have been proposed. Hydroxychloroquine has in vitro anti-viral and immunomodulatory activity, but there is no current clinical evidence of its effectiveness changing the outcome of the disease. Methods: We enrolled all 18-85 years old inpatients from Central Defense Hospital “Gómez Ulla”, Madrid, Spain, who were hospitalised for COVID-19 and had a definitive outcome (dead or discharged). We used a statistical survival analysis to detect treatment differences associated with in-hospital death. Results: We analysed first 220 medical records. 166 patients met the inclusion criteria. 48,8 % of patients not treated with HCQ died, 22% of those treated with hydroxychloroquine (p=0,002). According to clinical picture at admission, hydroxychloroquine increased the mean cumulative survival in all groups from 1,4 to 1,8 times. This difference was statistically significant in the mild group. Conclusions: in a cohort of 166 patients from 18 to 85 years hospitalised with COVID-19, hydroxychloroquine treatment with 800mg added loading dose increased survival when patients were admitted in early stages of the disease. There was a non-statistically significant trend towards survival in all groups, which will have to be clarified in subsequent studies.
Fri, 16 December 2016
Subject: Social Sciences, Sociology Keywords: depression; measurement scale; ratings; literature review
Online: 16 December 2016 (07:57:02 CET)
The range of rating instruments in depression measurement and the depth of their analytical relevance constitutes a major development in this psychiatric and psychotherapeutic field of mental health. Though the competition is acute amongst these various instruments, the results for the public have been outstandingly positive. A depression rating scale is essentially a psychiatric measuring instrument utilized in the identification and ranking of depression severity within the patient. The scale provides the practitioner, psychiatrist or psychotherapist, with sufficient information to assess the severity of the depression plotted on the scale. Not used as a “diagnostic tool” itself, nevertheless, the depression rating scale does function as an effective device for designating and assigning a behavioral score which may, then, be used in establishing the severity of depression of value in the designation of a diagnosis and treatment formula. In this paper, we will take a close look at the leading depression rating scales and briefly summarize their scope of assessment value in rating depression.
Wed, 4 November 2020
REVIEW | doi:10.20944/preprints202010.0330.v2
Subject: Medicine & Pharmacology, Allergology Keywords: COVID-19; Public Health; Lockdowns; Cost-benefit analysis; Groupthink
Online: 4 November 2020 (10:14:33 CET)
The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused the Coronavirus Disease 2019 (COVID-19) worldwide pandemic in 2020. In response, most countries in the world implemented lockdowns, restricting their population’s movements, work, education, gatherings, and general activities in attempt to ‘flatten the curve’ of COVID-19 cases. The public health goal of lockdowns was to save the population from COVID-19 cases and deaths, and to prevent overwhelming health care systems with COVID-19 patients. In this narrative review I explain why I changed my mind about supporting lockdowns. First, I explain how the initial modeling predictions induced fear and crowd-effects [i.e., groupthink]. Second, I summarize important information that has emerged relevant to the modeling, including about infection fatality rate, high-risk groups, herd immunity thresholds, and exit strategies. Third, I describe how reality started sinking in, with information on significant collateral damage due to the response to the pandemic, and information placing the number of deaths in context and perspective. Fourth, I present a cost-benefit analysis of the response to COVID-19 that finds lockdowns are far more harmful to public health than COVID-19 can be. Controversies and objections about the main points made are considered and addressed. I close with some suggestions for moving forward.
Thu, 21 December 2017
ARTICLE | doi:10.20944/preprints201712.0150.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Philippines; rainfall; precipitation; Gamma distribution; probability; weather risk
Online: 21 December 2017 (04:43:17 CET)
Philippines as an archipelago and tropical country, which is situated near the Pacific ocean, faces uncertain rainfall intensities. This makes environmental, agricultural and economic systems affected by precipitation difficult to manage. Time series analysis of Philippine rainfall pattern has been previously done, but there is no study investigating its probability distribution. Modeling the Philippine rainfall using probability distributions is essential, especially in managing risks and designing insurance products. Here, daily and cumulative rainfall data (January 1961 - August 2016) from 28 PAGASA weather stations are fitted to probability distributions. Moreover, the fitted distributions are examined for invariance under subsets of the rainfall data set. We observe that the Gamma distribution is a suitable fit for the daily up to the ten-day cumulative rainfall data. Our results can be used in agriculture, especially in forecasting claims in weather index-based insurance.
Mon, 10 August 2020
ARTICLE | doi:10.20944/preprints202008.0246.v1
Subject: Social Sciences, Education Studies Keywords: COVID-19; university student; sociodemographic factors, satisfaction; perception; online learning; mental health; habits; institutions; continents
Online: 10 August 2020 (15:21:04 CEST)
The paper aims to present the most comprehensive and large-scale study to date of students’ perceived impacts of COVID-19 crisis on different aspects of their lives on a global level. The study with a sample of 30,383 students from 62 countries reveals that due to worldwide lockdown and transition to online learning students were most satisfied with the support of teaching staff and universities’ public relations. Nevertheless, a lack of computer skills and the perception of increased workload prevented them from perceiving higher performance in a new teaching environment. Students were mainly concerned about their future professional career and studying issues, and were feeling boredom, anxiety and frustration. The pandemic encouraged some hygienic behaviors (i.e. wearing masks, washing hands) and discouraged certain daily habits (i.e. leaving home, shaking hands). Students were also more satisfied with the role of hospitals and universities during the epidemic, compared to government and banks. Further findings demonstrate that students with selected sociodemographic characteristics (male, part-time, first level, applied sciences, lower living standard, from Africa or Asia) were, in general, more strongly affected by the pandemic as they were significantly less satisfied with their academic work/life. Key factors influencing students' satisfaction with the role of university have also been identified. Policymakers and higher education institutions worldwide may benefit from these findings when formulating policy recommendations and tactics on how to support students during the pandemic.
Mon, 5 June 2017
ARTICLE | doi:10.20944/preprints201706.0029.v1
Subject: Keywords: teaching and learning ıssues in mathematics; social ıssues in mathematics education; cultural ıssues in mathematics education; political ıssues in mathematics education; technological ıssues in mathematics education
Online: 5 June 2017 (06:13:28 CEST)
In this paper, we discuss major issues of mathematics teaching and learning in Nepal. The issues coming from theories such as social and radical constructivism suggest that teachers are not trained to use such approach in teaching mathematics, and there is a lack of teaching aids and materials and technological tools. The issues related to social aspects are gender issues, language issues, social justice issues, and issues related to the achievement gap. The cultural issues are related to the diversity of language and ethnicity. The issues related to political aspects are equity and access, economic status, pedagogical choice, and professional organizations and unions. The issues related to technology include the technological skills, use of technology, and affordance. Finally, we suggest that all the stakeholders should pay attention to resolving these issues by improving the curriculum, training teachers, resourcing the classroom with locally made and new technological tools.
Tue, 17 March 2020
HYPOTHESIS | doi:10.20944/preprints202003.0279.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: chloroquine; COVID-19; SARS-CoV2; antiviral; viral prophylaxis
Online: 17 March 2020 (15:57:38 CET)
The novel coronavirus 2019 (COVID-19) pandemic is rapidly advancing despite public health measures. Pharmaceutical prophylaxis is an established approach to potentially control infectious diseases and is one solution to the urgent public health challenge posed by COVID-19. Screening and development of new vaccines and antivirals is expensive and time consuming while the repositioning of available drugs should receive priority attention as well as international government and agency support. Here we propose an old drug chloroquine (CQ) to be urgently repositioned as an ideal antiviral prophylactic against COVID-19. CQ has ability to block viral attachment and entry to host cells. Its proven clinical efficacy against a variety of viruses including COVID-19 and its current deployment in COVID-19 therapeutic trials strengthens its potential candidacy as a prophylactic. Furthermore, CQ has a long safety record, is inexpensive and widely available. Here we reviewed CQ's antiviral mechanisms, its laboratory efficacy activity against COVID-19, as well as CQ's pharmacokinetics in its established use against malaria and autoimmune diseases to recommend safe and potentially efficacious dose regimens for protection against COVID-19: a pre-exposure prophylaxis of 250-500mg daily and post-exposure prophylaxis at 8mg/kg/day for 3 days. We recommend further urgent research on CQ for COVID-19 prevention and urge that the above regimens be investigated in parallel with mass deployment by relevant agencies in attempts to contain the pandemic without unnecessary regulatory delays as benefits far outweigh risks or costs.
Tue, 7 April 2020
REVIEW | doi:10.20944/preprints202004.0103.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: Coronavirus; SARS-CoV-2; Medical Laboratory; Resource-limited setting, Good Laboratory Practice (GLP)
Online: 7 April 2020 (12:11:35 CEST)
The 2019 Coronavirus pandemic which was initially referred to as 2019-nCoV, was first identified in Wuhan, China. Early response from the Chinese government included quarantine of infected persons, isolation and total lockdown of Wuhan province to prevent further spread. With the spread of the disease across national borders and declaration of the disease as a global pandemic, there has been a robust response by the international community to contain this deadly virus and prevent its further spread worldwide. Africa is not left out of this rampaging pandemic with documented cases in over 40 countries and still rising. Although extensive studies have been carried out on the novel SARS-CoV-2 on its pathogenesis, mode of infection and virulence but much is still unknown. However, potentially infectious samples are received routinely in the medical laboratory for analysis. This technical note reviews good laboratory practice (GLP) and processes across the different specialities of Medical Laboratory practice that should minimize the risk of infection to laboratory staff especially in resource-limited settings.
Mon, 2 October 2017
ARTICLE | doi:10.20944/preprints201710.0008.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: : microstrip antenna, vertical slots , adaptive network-based fuzzy Inference system , resonant frequency, artificial neural networks
Online: 2 October 2017 (09:16:02 CEST)
This paper attempts at applying adaptive network-based fuzzy inference system (ANFIS) for analysis of the resonant frequency of a microstrip rectangular patch antenna with two equal size slots which are placed on the patch vertically. The resonant frequency is calculated as the position of slots is shifted to the right and left sides on the patch. As a result , the antenna resonates at more than one frequency . Commonly, machine algorithms based on artificial neural networks are employed to recognize the whole resonant frequencies. However ,they fail to estimate the resonant frequencies correctly as in some cases variations are not very sensible and the resonant frequencies overlap each other . It can be concluded that artificial neural networks could be replaced in such designs by the adaptive network-based fuzzy Inference system due to its high approximation capability and much faster convergence rate.
Tue, 14 March 2017
ARTICLE | doi:10.20944/preprints201703.0086.v1
Subject: Engineering, General Engineering Keywords: image enhancement; image fusion; color space; edge detector; underwater image
Online: 14 March 2017 (17:52:48 CET)
In order to improve contrast and restore color for underwater image captured by camera sensors without suffering from insufficient details and color cast, a fusion algorithm for image enhancement in different color spaces based on contrast limited adaptive histogram equalization (CLAHE) is proposed in this article. The original color image is first converted from RGB color space to two different special color spaces: YIQ and HSI. The color space conversion from RGB to YIQ is a linear transformation, while the RGB to HSI conversion is nonlinear. Then, the algorithm separately operates CLAHE in YIQ and HSI color spaces to obtain two different enhancement images. The luminance component (Y) in the YIQ color space and the intensity component (I) in the HSI color space are enhanced with CLAHE algorithm. The CLAHE has two key parameters: Block Size and Clip Limit, which mainly control the quality of CLAHE enhancement image. After that, the YIQ and HSI enhancement images are respectively converted backward to RGB color. When the three components of red, green, and blue are not coherent in the YIQ-RGB or HSI-RGB images, the three components will have to be harmonized with the CLAHE algorithm in RGB space. Finally, with 4 direction Sobel edge detector in the bounded general logarithm ratio operation, a self-adaptive weight selection nonlinear image enhancement is carried out to fuse YIQ-RGB and HSI-RGB images together to achieve the final fused image. The enhancement fusion algorithm has two key factors: average of Sobel edge detector and fusion coefficient, and these two factors determine the effects of enhancement fusion algorithm. A series of evaluate metrics such as mean, contrast, entropy, colorfulness metric (CM), mean square error (MSE) and peak signal to noise ratio (PSNR) are used to assess the proposed enhancement algorithm. The experiments results showed that the proposed algorithm provides more detail enhancement and higher values of colorfulness restoration as compared to other existing image enhancement algorithms. The proposed algorithm can suppress effectively noise interference, improve the image quality for underwater image availably.
Tue, 18 April 2017
ARTICLE | doi:10.20944/preprints201704.0101.v1
Subject: Social Sciences, Law Keywords: tax taxation power; principles of tax; tax adjudication; constitutional tax rules; Ethiopian constitution; Turkish Constitution
Online: 18 April 2017 (02:41:03 CEST)
Constitutions as supreme legal authorities enshrine the principles of taxation which are often used as the guidance to the legislations related to fiscal aspect, requires to be explored critically so as to provide clear understanding on taxation. This article has explored the tax provisions in the constitutions of Ethiopia and Turkey from comparative perspective through the method of doctrinal legal analysis. Both the latest constitution of Turkey and Ethiopia comprise relatively related principles regarding taxation in spite of the disparities of taxation system in these two countries due to the fact that Turkey is a unitary state whereas Ethiopia is federal. In-fact, there are some disparities within these constitutions. For instance, the 1982 Constitution of Turkey specifies the citizens' duties to pay tax and the adjudication system of tax in different way than the Ethiopian 1995 constitution. The Ethiopian constitution enshrines the taxation power in detail among other things in line with the federal system of government.
Tue, 8 August 2017
ARTICLE | doi:10.20944/preprints201708.0033.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: petroleum sludge; characterization; total organic carbon; metal concentration
Online: 8 August 2017 (13:24:39 CEST)
Thermal plasma technique is becoming prominent in the treatment of variety of waste ranging from municipal solid waste, incinerator residue, hospital waste, electronics waste and industrial sludge. Application of the new treatment technology to petroleum sludge requires information on the nature and characteristics of the sludge that will be use to optimize the treatment system. In this investigation, petroleum sludge obtained from Petronas Melaka was characterized for its physical and chemical features. Proximate and ultimate analysis as well as determination of elemental composition were carried out. The sludge was found to contain high moisture (78.91%), low ash (5.06%), low volatiles (5.52%) and high fixed carbon (10.51%). The sludge has a TOC of 54.48% and HHV of 23.599MJ/kg. Despite the high moisture content, the higher heating value (HHV) is high when compared to literature values. The high value of HHV may be associated with the high fixed carbon, low ash content and high value of TOC. The apparent density of the sludge is slightly lower. Fourteen heavy metals are detected in significant quantities. Proper waste management that will safely dispose the sludge is required. The waste disposal technique should take into cognizant the possibility of leaching of heavy metals into ground water on one hand and the gasification of lighter ones on the other.
Thu, 15 October 2020
REVIEW | doi:10.20944/preprints202010.0330.v1
Subject: Medicine & Pharmacology, Allergology Keywords: COVID-19; Public Health; Lockdowns; Cost-benefit analysis
Online: 15 October 2020 (16:02:58 CEST)
The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused the Coronavirus Disease 2019 (COVID-19) worldwide pandemic in 2020. In response, most countries in the world implemented lockdowns, restricting their population’s movements, work, education, gatherings, and general activities in attempt to ‘flatten the curve’ of COVID-19 cases. The public health goal of lockdowns was to save the population from COVID-19 cases and deaths, and to prevent overwhelming health care systems with COVID-19 patients. In this narrative review I explain why I changed my mind about supporting lockdowns. First, I explain how the initial modeling predictions induced fear and crowd-effects [i.e., groupthink]. Second, I summarize important information that has emerged relevant to the modeling, including about infection fatality rate, high-risk groups, herd immunity thresholds, and exit strategies. Third, I describe how reality started sinking in, with information on significant collateral damage due to the response to the pandemic, and information placing the number of deaths in context and perspective. Fourth, I present a cost-benefit analysis of the response to COVID-19 that finds lockdowns are far more harmful to public health than COVID-19 can be. I close with some suggestions for moving forward.
Sun, 12 July 2020
REVIEW | doi:10.20944/preprints202004.0203.v3
Subject: Medicine & Pharmacology, General Medical Research Keywords: COVID-19; SARS-CoV-2; masks; pandemic
Online: 12 July 2020 (16:11:50 CEST)
The science around the use of masks by the general public to impede COVID-19 transmission is advancing rapidly. Policymakers need guidance on how masks should be used by the general population to combat the COVID-19 pandemic. In this narrative review, we develop an analytical framework to examine mask usage, considering and synthesizing the relevant literature to inform multiple areas: population impact; transmission characteristics; source control; PPE; sociological considerations; and implementation considerations. A primary route of transmission of COVID-19 is via respiratory droplets, and is known to be transmissible from presymptomatic and asymptomatic individuals. Reducing disease spread requires two things: first, limit contacts of infected individuals via physical distancing and other measures, and second, reduce the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces the transmissibility per contact by reducing transmission of infected droplets in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. The decreased transmissibility could substantially reduce the death toll and economic impact while the cost of the intervention is low. Given the current shortages of medical masks we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory droplets become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask-wearing by infectious people ("source control") with benefits at the population-level, rather than mask-wearing by susceptible people, such as health-care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.
Thu, 19 July 2018
ARTICLE | doi:10.20944/preprints201807.0366.v1
Online: 19 July 2018 (15:43:50 CEST)
This paper investigates how Islamic tolerance contributes to solve religious conflict today that has impacted on various aspects such as economic collapse, insecurity in life, lack of professional society, academic retrogressions, and so on. Knowledge of these issues has become an urgent to build a community that is full of peace, harmony and unity. The paper suggests that Quranic views on tolerance should be understood and practiced in order to avoid disunity in society which is due to failure to appreciate tolerance values in association. The paper concludes problems or misunderstandings always occur in different religious societies, since every religion has its own teachings and principles, as well as each of them is interpreted in different ways.
Thu, 30 April 2020
REVIEW | doi:10.20944/preprints202004.0548.v1
Subject: Keywords: COVID-19; coronavirus; SARS-CoV-2; aging; immunosenescence; inflammaging; inflammation; cytokine storm; epigenetics; biological clock; sirtuin; glycome
Online: 30 April 2020 (22:38:53 CEST)
The severity and outcome of coronavirus disease 2019 (COVID-19) largely depends on a patient’s age. Over 80% of hospitalizations are of those over 65 years of age with a 23-fold greater risk of death. In the clinic, COVID-19 patients most commonly present with fever, cough and dyspnea. Particularly in those over 65, it can progress to pneumonia, lung consolidation, cytokine release syndrome, endotheliitis, coagulopathy, multiple organ failure and death. Comorbidities such as cardiovascular disease, diabetes, obesity and hypertension increase the chances of fatal disease, but they alone do not explain the variability in COVID-19 symptoms. Here, we present the molecular differences between the young, middle-aged and elderly that may determine whether COVID-19 is a mild or life-threatening illness. We also discuss several biological age clocks that could be used in conjunction with genetic tests to identify both the mechanisms of the disease and individuals most at risk. Finally, based on these mechanisms, we discuss treatments that could increase survival in the elderly, not simply by inhibiting the virus, but by restoring patients’ ability to clear the infection.
Sun, 1 March 2020
REVIEW | doi:10.20944/preprints202003.0001.v1
Subject: Medicine & Pharmacology, Other Keywords: emerging coronavirus; 2019-nCoV; SARS-CoV-2; COVID-19; diagnosis; vaccines; therapy; one health
Online: 1 March 2020 (02:48:13 CET)
In the past decades, several new diseases have emerged in new geographical areas, with pathogens including Ebola, Zika, Nipah, and coronaviruses (CoV). Recently, a new type of viral infection has emerged in Wuhan City, China, and initial genomic sequencing data of this virus does not match with previously sequenced CoVs, suggesting a novel CoV strain (2019-nCoV), which has now been termed as severe acute respiratory syndrome CoV-2 (SARS-CoV-2). Although CoV disease 2019 (COVID-19) is suspected to originate from an animal host (zoonotic origin) followed by human-to-human transmission, the possibility of other routes such as food-borne transmission should not be ruled out. Compared to diseases caused by previously known human CoVs, COVID-19 shows a less severe pathogenesis but higher transmission competence, as is evident from the continuously increasing number of confirmed cases. Compared to other emerging viruses such as Ebola virus, avian H7N9, SARS-CoV, or MERS-CoV, SARS-CoV-2 has shown relatively low pathogenicity and moderate transmissibility Codon usage studies suggest that this novel virus may have been transferred from an animal source such as bats. Early diagnosis by real-time PCR and next-generation sequencing has facilitated the identification of the pathogen at an early stage. Since no antiviral drug or vaccine exists to treat or prevent SARS-CoV-2, potential therapeutic strategies that are currently being evaluated predominantly stem from previous experience with treating SARS-CoV, MERS-CoV, and other emerging viral diseases. In this review, we address epidemiological, diagnostic, clinical, and therapeutic aspects, including perspectives of vaccines and preventive measures that have already been globally recommended.
Tue, 31 March 2020
ARTICLE | doi:10.20944/preprints202003.0455.v1
Online: 31 March 2020 (10:16:13 CEST)
Background: COVID-19, a member of corona virus family is spreading its tentacles across the world due to lack of drugs at present. Associated with its infection are cough, fever and respiratory problems causes more than 15% mortality worldwide. It is caused by a positive, single stranded RNA virus from the enveloped coronaviruse family. However, the main viral proteinase (Mpro/3CLpro) has recently been regarded as a suitable target for drug design against SARS infection due to its vital role in polyproteins processing necessary for coronavirus reproduction.Objectives: The present in silico study was designed to evaluate the effect of Eucalyptol (1,8 cineole), a essential oil component from eucalyptus oil, on Mpro by docking study.Methods: In the present study, molecular docking studies were conducted by using 1-click dock and swiss dock tools. Protein interaction mode was calculated by Protein Interactions Calculator.Results: The calculated parameters such as RMSD, binding energy, and binding site similarity indicated effective binding of eucalyptol to COVID-19 proteinase. Active site prediction further validated the role of active site residues in ligand binding. PIC results indicated that, Mpro/eucalyptol complexes forms hydrophobic interactions, hydrogen bond interactions and strong ionic interactions.Conclusions: Therefore, eucalyptol may represent potential treatment potential to act as COVID-19 Mpro inhibitor. However, further research is necessary to investigate their potential medicinal use.
Tue, 2 January 2018
ARTICLE | doi:10.20944/preprints201801.0010.v1
Online: 2 January 2018 (10:10:51 CET)
Although the phenomenon of serial killers has received great attention from media, governments, and public, very little information is known about them and very few theories are presented by researchers specifically their definition and motives for killing. Through cross tabulation analysis of top ninety-eight serial killers, this present study poses six questions that investigate the correlations between, offender's gender, offender's level of education, time span of killing, killing severity, number of victims, killer's type of abuse, motives for killing, and victim's profile. Findings show that males kill more than females and for longer time, less educated serial killers kill more horribly, female serial killers consider their family members easy target, and finally males kill most for enjoyment and sex and females kill for financial gains.
Tue, 30 August 2016
ARTICLE | doi:10.20944/preprints201608.0159.v2
Subject: Social Sciences, Economics Keywords: public investment; domestic private investment; FDI; crowding out effect; economic growth
Online: 30 August 2016 (04:03:38 CEST)
This paper analyzes the causal effect between domestic private investment, public investment, foreign direct investment and economic growth in Tanzania during the 1970-2014 period. The modified neo-classical growth model is used to estimate the ieffect of investment on economic growth. Also, the economic growth models based on Phetsavong and Ichihashi (2012) , and Le and Suruga (2005) are used to estimate the crowding out effect of public investment on domestic private investment on one hand and foreign direct investment on the other hand. In the same way, the crowding out effect of foreign direct investment on domestic private investment is estimated. A correlation test is applied to check the correlation among independent variables, and the results show that there is very low correlation suggesting that multicollinearity is not a serious problem. Moreover, the diagnostic tests including RESET regression errors specification test, Breusch-Godfrey serial correlation LM test, Jacque-Bera-normality test and white heteroskedasticity test reveal that the model has no signs of misspecification and that, the residuals are serially uncorrelated, normally distributed and homoskedastic. Broadly, the empirical results show that the domestic private investment and foreign direct investment play an important role in economic growth in Tanzania. Besides, a revealed negative, albeit weak, association between public and private investment suggests that the positive effect of domestic private investment on economic growth becomes smaller when public investment-to-GDP ratio exceeds 8-10 percent. Similarly, foreign direct investment tends to marginally reduce the impact of domestic private investment on growth. These results suggest that public investment and foreign direct investment need to be considered carefully in order to avoid a reduced positive impact of domestic private investment on growth. Domestic saving may be promoted to encourage domestic investment for economic growth.
Mon, 12 September 2016
Subject: Social Sciences, Geography Keywords: circular economy; social ecology; consumerism; dialectical naturalism; mining
Online: 12 September 2016 (09:55:09 CEST)
The concept of a "circular economy" needs a more cogent theoretical anchor which will allow for transference of its goals and methods of attainment across cases. Tensions between ecological goals of this concept and the social implications of its implementation need to be addressed. This paper attempts to provide a theoretical framework for harnessing the strengths of a circular economy. Building on theories of social ecology which are predicated in Murray Bookchin's notion of "dialectical naturalism", the analysis presented here addresses some of the criticism of circular economic paradigms, such as their potential for stifling innovation or a neglect of human development challenges. A model for managing human "need" and "greed" within a circular economy framework is presented that also incorporates consumer choice and innovation. Planned obsolescence as a means of livelihood generation is also problematized with a view towards balancing durability of products on the one hand and ensuring throughput for manufacturing employment and innovation incentives on the other. Finally, the need for governance systems is considered to ensure that a planetary vision for a circular economy can be realized that efficiently harnesses local initiatives rather than an atomized and insular view of circularity.
Sat, 29 February 2020
BRIEF REPORT | doi:10.20944/preprints202002.0242.v2
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: COVID-19; molecular docking; HIV protease inhibitor; nucleotide analogues
Online: 29 February 2020 (12:43:40 CET)
The outbreak of novel coronavirus (COVID-19) infections in 2019 is in dire need of finding potential therapeutic agents. In this study, we used molecular docking to repurpose HIV protease inhibitors and nucleoside analogues for COVID-19, with evaluations based on docking scores calculated by AutoDock Vina and RosettaCommons. Our results suggest that Indinavir and Remdesivir possess the best docking scores, and comparison of the docking sites of the two drugs reveal a near perfect dock in the overlapping region of the protein pockets. After further investigation of the functional regions inferred from the proteins of SARS coronavirus, we discovered that Indinavir does not dock on any active sites of the protease, which may give rise to concern in regards to the efficacy of Indinavir. On the other hand, the docking site of Remdesivir is not compatible with any known functional regions, including template binding motifs, polymerization motifs and nucleoside triphosphate (NTP) binding motifs. However, when we tested the active form (CHEMBL2016761) of Remdesivir, the docking site revealed a perfect dock in the overlapping region of the NTP binding motif. This result suggests that Remdesivir could be a potential therapeutic agent. Clinical trials still must be done in order to confirm the curative effect of these drugs.
Tue, 27 November 2018
REVIEW | doi:10.20944/preprints201811.0601.v1
Subject: Engineering, Civil Engineering Keywords: Drone, Remote Sensing, control station, Multispectral, Aviation, Regulations
Online: 27 November 2018 (12:08:39 CET)
In past few years, unmanned aerial vehicles (UAV) or drones has been a hot topic encompassing technology, security issues, rules and regulations globally due to its remarkable advancements and uses in remote sensing and photogrammetry applications. This review paper highlights the evolution and development of UAV, classification and comparison of UAVs along with Hardware and software design challenges with diverse capabilities in civil and military applications. Further, safety and security issues with drones, existing regulations and guidelines to fly the drone, limitations and possible solutions have also been discussed.
Tue, 7 July 2020
ARTICLE | doi:10.20944/preprints202007.0129.v1
Online: 7 July 2020 (16:26:57 CEST)
The effect of the COVID-19 pandemic in a developing country like Bangladesh is enormous. A research conducted by South Asian network of Economic Modelling predicted that the pandemic could double the poverty. But it is not that only the socioeconomic condition is dropping in Bangladesh, the impact of COVID-19 pandemic is manifold. The poor condition of Bangladesh's health sector has also been exposed due to the pandemic. People are not getting proper treatment due to lack of isolation beds, oxygen, ICU etc. The health sector of Bangladesh is not much developed and now with this pandemic it has become impossible to provide treatment facility for all the patients. Education sector, which is the backbone of a country,has also been greatly affected by the pandemic. We know that different types of cultural occasions are an inherited tradition of Bangladesh, COVID-19 have not even spared these traditions, all the cultural programes and festivals have been cancelled due to this pandemic.In this paper, our aim is to present the present status of all these sectors.
Thu, 15 March 2018
ARTICLE | doi:10.20944/preprints201803.0122.v1
Subject: Engineering, Energy & Fuel Technology Keywords: electric vehicle; Nissan Leaf; lithium-ion battery; capacity loss; battery degradation
Online: 15 March 2018 (07:19:52 CET)
Analysis of 1382 measures of battery State of Health (SoH) from 283 Nissan Leafs (“Leaf/s”), manufactured between 2011 and 2017, has detected a faster rate of decline in this measure of energy-holding capacity for 30 kWh variants. At two years of age, the mean rate of decline of SoH of 30 kWh Leafs was 9.9% per annum (95% uncertainty interval of 8.7% to 11.1%; n = 82). This was around three times the rate of decline of 24 kWh Leafs which at two years averaged 3.1% per annum (95% uncertainty interval of 2.9% to 3.3%; n = 201). For both variants there was evidence for an increasing rate of decline as they aged, although this was much more pronounced in the 30 kWh Leafs. Higher use of rapid DC charging was associated with a small decrease in SoH. Additionally, while 24 kWh cars with greater distances travelled showed a higher SoH, in 30 kWh cars there was a reduction in SoH observed in cars that had travelled further. The 30 kWh Leafs sourced from United Kingdom showed slower initial decline than those from Japan, but the rate of decline was similar at two years of age. Improvements in the battery health diagnostics, continuous monitoring of battery temperatures and state of charge, and verification of a fundamental model of battery health are needed before causes and remedies for the observed decline can be pinpointed. If the high rate of decline in battery capacity that we observed in the first 2.3 years of a 30 kWh Leaf’s lifetime were to continue, the financial and environmental benefits of this model may be significantly eroded. Despite 30 kWh Leafs accounting for only 14% of all light battery electric vehicles registered for use on New Zealand roads at the end of February 2018, there is also the potential for the relatively poor performance of this specific model to undermine electric vehicle uptake more generally unless remedies can be found.
Fri, 29 July 2016
ARTICLE | doi:10.20944/preprints201607.0093.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: Non-volatile Memories; NAND Flash Memories; Storage Memories
Online: 29 July 2016 (13:40:38 CEST)
This paper presents an upcoming nonvolatile memories (NVM) overview. Non-volatile memory devices are electrically programmable and erasable to store charge in a location within the device and to retain that charge when voltage supply from the device is disconnected. The non-volatile memory is typically a semiconductor memory comprising thousands of individual transistors configured on a substrate to form a matrix of rows and columns of memory cells. Non-volatile memories are used in digital computing devices for the storage of data. In this paper we have given introduction including a brief survey on upcoming NVM's such as FeRAM, MRAM, CBRAM, PRAM, SONOS, RRAM, Racetrack memory and NRAM. In future Non-volatile memory may eliminate the need for comparatively slow forms of secondary storage systems, which include hard disks.
Mon, 23 March 2020
REVIEW | doi:10.20944/preprints202003.0346.v1
Subject: Medicine & Pharmacology, Other Keywords: COVID-19; nCoV 19; oxidative stress; PARP; PARG; TRPM2
Online: 23 March 2020 (07:40:50 CET)
The emerging new Coronaviridae member, nCoV 19, outbreak announced a pandemic by WHO with an increased morbidity and mortality rate worldwide. nCoV 19 known as the third highly pathogen coronavirus in the human population after the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), the nCoV 19. The renin-angiotensin (RAS) signaling pathway, oxidative stress and cell death, cytokines storm and endothelial dysfunction are four major pathways involved in the pathogenesis of nCoV 19. Acute respiratory distress syndrome (ARDS) generally develops with a massive oxidative/nitrosative stress following virus entry and RAS activation. The DNA damage subsequent to oxidative burst activates poly-ADP ribose polymerase-1 (PARP-1), viral macrodomain (NSP3) poly (ADP-ribose) glycohydrolase (PARG) and transient receptor potential channel, melastatin 2 (TRPM2) in a sequential manner ultimately leading to apoptosis and necrosis due to NAD and ATP depletion. Regarding the molecular mechanisms involved in nCoV 19 pathogenesis, angiotensin II receptor blockers and/or PARP, PARG and TRPM2 blockers could be engaged as therapeutic candidates for inhibition of RAS and quenching oxidative stress, respectively. In this review, the molecular aspects of nCoV 19 pathogenesis would be studied precisely and possible therapeutic targets would be proposed. It is recommended to evaluate the proposed drugs and supplements via registered clinical trials along with conventional guideline-based multi-drug regimen.
Fri, 8 July 2016
ARTICLE | doi:10.20944/preprints201607.0010.v1
Subject: Social Sciences, Finance Keywords: Stock Beta, Endogenous Structural Breaks, Time Horizon
Online: 8 July 2016 (08:35:15 CEST)
The stock beta coefficient literature extensively discusses the proper methods for the estimation of beta as well as its use in asset valuation. However, there are relatively few references with respect to the appropriate time horizon that investors should utilize when evaluating the risk-return relationship of a stock. We examine the appropriate time horizon for beta estimation differentiating our results by sector according to the Industry Classification Benchmark. We employ data from the NYSE and we estimate varying lengths of beta employing data from 30 to 250 trading days. The constructed beta series is then examined for the presence of breaks using the endogenous structural break literature. Results show evidence against the use of betas that employ more than 90 trading days of data provisional to the sector under study.
Mon, 5 November 2018
ARTICLE | doi:10.20944/preprints201811.0096.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: machine learning; stacking; forecasting; regression; sales; time series
Online: 5 November 2018 (09:54:54 CET)
In this paper, we study the usage of machine learning models for sales time series forecasting. The effect of machine learning generalization has been considered. A stacking approach for building regression ensemble of single models has been studied. The results show that using stacking technics, we can improve the performance of predictive models for sales time series forecasting.
Thu, 8 August 2019
Subject: Engineering, Automotive Engineering Keywords: lidar, ladar, time of flight, 3D imaging, point cloud, MEMS, scanners, photodetectors, lasers, autonomous vehicles, self-driving car
Online: 8 August 2019 (12:23:48 CEST)
Imaging lidars are one of the hottest topics in the optronics industry. The need to sense the surroundings of every autonomous vehicle has pushed forward a career to decide the final solution to be implemented. The diversity of state-of-the art approaches to the solution brings, however, a large uncertainty towards such decision. This results often in contradictory claims from different manufacturers and developers. Within this paper we intend to provide an introductory overview of the technology linked to imaging lidars for autonomous vehicles. We start with the main single-point measurement principles, and then present the different imaging strategies implemented 8 in the different solutions. An overview of the main components most frequently used in practice is also presented. Finally, a brief section on pending issues for lidar development has been included, 10 in order to discuss some of the problems which still need to be solved before an efficient final implementation.Beyond this introduction, the reader is provided with a detailed bibliography containing both relevant books and state of the art papers.
Tue, 14 February 2017
REVIEW | doi:10.20944/preprints201702.0045.v1
Online: 14 February 2017 (03:08:37 CET)
Biodiversity has become an issue of global anxiety over the past decades due to its rapid decline worldwide. Bangladesh as one of the most densely populated countries in the world is no more exception. The country, although, was once very rich in biodiversity, during the last few decades as a consequence of the rapid reduction in forest area, urbanisation, habitat modification, unsustainable natural resources use and collection and overall climate change it has decreased alarmingly. Of late, the government, as a signatory of various regional and international conservation treaties, has taken various initiatives to improve country’s dwindling biodiversity. This paper reviews the present situation of biodiversity in Bangladesh, management trends and major causes of biodiversity loss. A separate statutory body is fundamental to ensure conservation, sustainable use and equitable sharing of benefits arisen from biodiversity in the country.
Wed, 11 July 2018
REVIEW | doi:10.20944/preprints201807.0198.v1
Subject: Biology, Ecology Keywords: Yabello rangeland; degradation; rehabilitation techniques; encroachment
Online: 11 July 2018 (11:56:31 CEST)
Background: Rangeland degradation means that a reduction both in rank and status of general floral/ fauna composition, energy flow and biomass of a certain ecosystem. Objective: The review was conducted to assess rangeland degradation, cause and its impact on local livelihood in Yabello district and also suggests appropriate methods used to rehabilitate it. Methods: The data and literatures were collected from different both domestic and abroad researcher research result reviewed and internet sources. The research paper review mainly addresses concepts of rangeland degradation, major causes in tropics and Ethiopia particularly in Yabello rangelands, impacts of rangeland degradation, principles of rangeland restoration and common restoration techniques.Result: Based on those research papers and the current fact situations the major drivers leading to rangeland degradation includes climate change, overgrazing, bush encroachment, both human and livestock population pressure, drought, and government policy . Of all bush encroachment is becoming the major threat to Yabello rangelands. And this led to decline in rangeland condition, water potential, soil status, and animal performance, livestock holding at the household level and community become destitute and in the long run poverty. In spite of these impacts, the action of restoration techniques in the area is highly insufficient. Conclusion: Generally in order to address rangeland degradation problems, there is a strong need to coordination between the local community and the scientific community for sustainable land management trough post management techniques by applying reseeding technology.
Fri, 3 August 2018
ARTICLE | doi:10.20944/preprints201808.0062.v1
Subject: Social Sciences, Education Studies Keywords: africanization; transformation; education; reform; challenges; prospects
Online: 3 August 2018 (05:34:55 CEST)
Africanization of education was a major policy option in most countries in Africa upon the attainment of independence. This is because of the perceived negative effects of colonial education. The paper is an empirical sources study which discusses Africanization as an epistemicide and analyses efforts by some African states to Africanize their educational systems. It concludes that while some countries embraced the idea and actually initiated policies to Africanize their educational systems, the general picture indicates that Africanization has not succeeded in most countries due to various challenges. Such challenges are identified and recommendations made which could be significant for the revamping of the policy.
Wed, 27 July 2016
ARTICLE | doi:10.20944/preprints201607.0082.v1
Subject: Arts & Humanities, General Humanities Keywords: Africa, African women, Christianity, Igbo society, patriarchy, post-colonialism, feminism, womanism
Online: 27 July 2016 (04:18:57 CEST)
The African society is one of the societies with rich culture and traditions. Apart from the indigenous religion of Africa, Christianity and Islam are worshiped as the major religions of the African society. Literature reflects a great amount of influence of religions on the existing societies, people and cultures. African literature often mirrors the clash of indigenous religion with Christianity. In the writings of African authors one can find the elements of Christian beliefs and practices. The present paper, however, is focused on the African woman novelist Buchi Emecheta’s selected four novels: Second-Class Citizen (1974), The Bride Price (1976), The Slave-Girl (1977) and The Joys of Motherhood (1979). The paper attempts to discuss the impact of Christianity on the social and cultural aspects of the African society with special focus on African women. The findings reveal the positive as well as negative impacts of the new religion on African people and on the position of African women through the characters present in the selected novels. With the medium of writing and through Christianity, Emecheta seek to educate her society and improve upon the position of the African women.
Fri, 9 September 2016
ARTICLE | doi:10.20944/preprints201609.0012.v2
Online: 9 September 2016 (07:42:15 CEST)
Solid waste management in Accra is a major challenge to the Metropolitan Authorities and inhabitants. The rapidly increasing population coupled with poor capacity of the municipal and private waste management companies to management waste effectively has created issues of environmental concern. Due to poor waste managements systems, most household dispose waste indiscriminately leading to floods and health issues. The study showed that about 60% of household waste is organic materials which has the potential to be converted to compost for agriculture purpose. Meanwhile plastics and rubbers which litters the environment as well as blocking major storm drains and gutters hence creating huge environmental hazard is made of 11% of the total component of most household waste generated daily. The study also revealed that among the methods of disposing waste, dumping waste in skip containers located at authorized places was the preferred means of disposing waste by household though others also dispose waste by other means such as burying and burning. Inadequate skip containers per population of household in an area coupled with irregularity of tracks picking these containers makes skip containers dumping site ugly scene, hence creating health issues. Among the constraints that impact negatively on sustainable waste management in Accra Metropolis, economic constraints was perceived as the main challenge which affect efficient waste management. Currently the country is going through serious economic challenges so government does not release money timely to fund projects which waste management is key. Most donor partners that use to support the government with funds have either reduced or redrawn their services as they have no confidence in the state of Ghana economy. Aside the constrains, the study also indicated that factors such as poor public attitude towards waste management, poor enforcement of sanitation by-laws, inadequate and untimely release of government funds were also seen as the main factors affecting waste management.
Thu, 27 September 2018
TECHNICAL NOTE | doi:10.20944/preprints201809.0539.v1
Subject: Mathematics & Computer Science, Probability And Statistics Keywords: Non-normality, Classical Linear Regression Model, Modified Maximum Likelihood Estimation.
Online: 27 September 2018 (10:04:26 CEST)
Regression models form the core of the discipline of econometrics. One of the basic assumptions of classical linear regression model is that the values of the explanatory variables are fixed in repeated sampling. However, in most of the real life cases, particularly in economics the assumption of fixed regressors is not always tenable. Under a non-experimental or uncontrolled environment, the dependent variable is often under the influence of explanatory variables that are stochastic in nature. There is a huge literature related to stochastic regressors in various aspects. In this paper, a historical perspective on some of the works related to stochastic regressor is being tried to pen down based on literature search.
Wed, 11 March 2020
CASE REPORT | doi:10.20944/preprints202003.0180.v1
Subject: Life Sciences, Virology Keywords: COVID-19; coronavirus; fulminant myocarditis; infection; echocardiography
Online: 11 March 2020 (04:57:10 CET)
Background: The Coronavirus Disease 2019 (COVID-19) has been demonstrated as the cause of pneumonia. Nevertheless, it has not been reported as the cause of acute myocarditis or fulminant myocarditis. Case Presentation: A 63-year-old male was admitted with pneumonia and cardiac symptoms. He was genetically confirmed as COVID-19 by testing sputum on the first day of admission. He also had an elevated troponin-I (Trop I) level and diffuse myocardial dyskinesia along with decreased left ventricular ejection fraction (LVEF) on echocardiography. The highest level of Interleukin 6 was 272.40pg/ml. Bedside chest radiograph had typical ground-glass changes of viral pneumonia. The laboratory test results of virus that can cause myocarditis are all negative. The patient conformed to the diagnostic criteria of Chinese expert consensus statement for fulminant myocarditis. After receiving antiviral therapy and mechanical life support, the Trop I reduced to 0.10 g/L, and Interleukin 6 was 7.63 pg/ml. Meanwhile the LVEF of the patient gradually recovered to 68%. Conclusion: COVID-19 patients may develop severe cardiac complications such as myocarditis and heart failure, and this is the first case of COVID-19 infection complicated with fulminant myocarditis. The mechanism of cardiac pathology caused by COVID-19 needs further study.
Thu, 23 November 2017
ARTICLE | doi:10.20944/preprints201711.0151.v1
Subject: Social Sciences, Other Keywords: psychopharmacology; mental health; addiction; biopsychology
Online: 23 November 2017 (08:51:06 CET)
This study investigated the psychosocial factors influencing substance abuse among undergraduates. The study was conducted in Ekiti State university Ado Ekiti. 150 participants who are undergraduates of the university were used in this research. They consist of 82 males and 68 females selected from all faculties in the institution. 3 questionnaires were administered to respondent to measure the factors influencing substance abuse and the level at which they are abused. Independent T-test, multiple regression and Pearson Correlation method were used to analyze the data collected. Five hypotheses were tested: hypothesis 1, 2, 3 and 4 were significant while hypothesis 5 was insignificant. It was observed that there was significant influence of religiosity on substance abuse among undergraduates, the result also revealed that there was a significant influence of self-esteem on substance abuse among undergraduates, it also revealed that religiosity and self-esteem jointly predicted substance abuse among undergraduates, likewise the result also show that there was significant influence of sex on substance abuse among undergraduates and finally the result revealed there was no significant relationship between religiosity and self-esteem among undergraduates. The results were discussed in line with relevant empirical literatures, while conclusion and recommendations subsequently followed.
Thu, 19 March 2020
ARTICLE | doi:10.20944/preprints202003.0300.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: coronavirus; COVID-19; diagnosis; deep features; SVM
Online: 19 March 2020 (13:49:49 CET)
The detection of coronavirus (COVID-19) is now a critical task for the medical practitioner. The coronavirus spread so quickly between people and approaches 100,000 people worldwide. In this consequence, it is very much essential to identify the infected people so that prevention of spread can be taken. In this paper, the deep learning based methodology is suggested for detection of coronavirus infected patient using X-ray images. The support vector machine classifies the corona affected X-ray images from others using the deep feature. The methodology is beneficial for the medical practitioner for diagnosis of coronavirus infected patient. The suggested classification model, i.e. resnet50 plus SVM achieved accuracy, FPR, F1 score, MCC and Kappa are 95.38%,95.52%, 91.41% and 90.76% respectively for detecting COVID-19 (ignoring SARS, MERS and ARDS). The classification model ResNet50 plus SVM is superior compared to other classification models. The result is based on the data available in the repository of GitHub, Kaggle and Open-i as per their validated X-ray images.
Thu, 27 February 2020
ARTICLE | doi:10.20944/preprints202002.0408.v1
Subject: Life Sciences, Microbiology Keywords: Wuhan SARS-CoV-2; ACE2; DC-SIGN; L-SIGN; expression; susceptibility; race; age; gender; smoking; single cell
Online: 27 February 2020 (12:45:26 CET)
The current spreading novel coronavirus SARS-CoV-2 is highly infectious and pathogenic and has attracted global attention. Recent studies have found that SARS-CoV-2 and SARS-CoV share around 80% of homology and use the same cell entry receptor, ACE2. These inspired us to study other receptors of SARS-CoV, which may be used for SARS-CoV-2 binding as well. In this study, we screened the gene expression of three receptors (ACE2, DC-SIGN and L-SIGN) in four datasets of normal lung tissue from lung adenocarcinoma patients and two single-cell RNA sequencing datasets from normal lung and bronchial epithelial cells separately. No significant difference in gene expression of these three receptors were found between gender groups (male vs female). We found higher gene expression of DC-SIGN in elder with age>60 and higher gene expression of L-SIGN in Caucasian than Asian. Similar to ACE2, we observed significantly higher DC-SIGN gene expression in the lungs of smokers, especially former smokers. However, smokers upregulate ACE2 and DC-SIGN gene expression in different cell types. In the whole lung, ACE2 is actively expressed in remodeled Alveolar Type II cells of former smokers, while DC-SIGN is largely expressed in monocytes of former smokers and dendritic cells of current smokers. In bronchial epithelium, no obvious gene expression of DC-SIGN and L-SIGN was observed while ACE2 was found to be actively expressed in goblet cells of current smokers and club cells of non-smokers. In conclusion, our findings may indicate that smokers, especially former smokers, and people over 60 have higher risk and are more susceptible to SARS-CoV-2 infection. Also, this study provides hints on possible SARS-CoV-2 pathogenicity mechanisms in lung infection.
Sun, 5 February 2017
ARTICLE | doi:10.20944/preprints201702.0014.v1
Subject: Earth Sciences, Atmospheric Science Keywords: temperature; precipitation; ethiopia; mann kendall; climate variability
Online: 5 February 2017 (08:56:29 CET)
Long term Precipitation and temperature variations are one of the main determinants of climate variability of one’s area. The aim of this study is to determine trends variation in climatic elements of temperature and precipitation in the southern zone of Tigray regional state, Ethiopia. The station is assumed for the study of climatic records over southern zone of the region in detection for probable trends. The daily, monthly and annual precipitation totals and temperature observed at korem meteorological station were used for the period of 1981-2010 for Precipitation and 1985 – 2010 for minimum and maximum temperature. Summary of descriptive statistics and Mann Kendall test methods were employed for the observed data analysis to demonstrate any existence of possible trends. The main findings of the study indicated that the mean and maximum temperature had a general increasing trend; however, minimum temperature showed decreasing trend. In general annual temperature from 1985 – 2010 of the area showed a warming trend. Moreover analysis of the 30 years (1981-2010) annual precipitation showed a coefficient of variation ranging from 33.77 – 233 %. It indicated that the precipitation dissemination is not normal with large year to year variances.
Sun, 23 February 2020
ARTICLE | doi:10.20944/preprints202002.0315.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: COVID-19; adipose tissue; cancer; ACE2
Online: 23 February 2020 (10:30:06 CET)
The spread of 2019 novel coronavirus disease (COVID-19) throughout the world has been a severe challenge for public health. The human angiotensin-converting enzyme 2 (ACE2) has a remarkably high affinity binding to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). By the search for network database and re-analysis of pubic data, we found the level of ACE2 expression in adipose tissue was higher than that in lung tissue, which indicated the adipose tissue might be vulnerable to SARS-CoV-2 as well; the levels of ACE2 expressed by adipocytes and adipose progenitor cells were similar between non-obese individuals and obese individuals, but obese individuals have more adiposes so as to increase the number of ACE2-expressing cells; the expression of ACE2 in tumor tissues posed by five different types of cancers increased significantly compared with that in adjacent tissues. Thus, we suggest that more attentions might be given to obese individuals and the five types of cancer patients during the outbreak of COVID-19.
Wed, 3 June 2020
ARTICLE | doi:10.20944/preprints202006.0013.v1
Subject: Social Sciences, Education Studies Keywords: online education; corona crisis; challenges; possibilities
Online: 3 June 2020 (08:25:46 CEST)
Online class now is the demand of the day as little scopes are to find out alternatives to online class in these unprecedented days caused by corona pandemic across the globe. The study was qualitative in approach and data were collected from secondary sources i.e. different newspapers and journals in the recent times along with a mini interview with students of private universities studying in different subjects over mobile phone by the researcher. Findings of the study show that though online education has a number of challenges faced by two main stakeholders; students and teachers, handling all these challenges carefully can have the chance to create a positive atmosphere in the field of education as an alternative teaching learning resulting in positive outcomes in all regards.
Thu, 12 March 2020
REVIEW | doi:10.20944/preprints202003.0197.v1
Subject: Biology, Other Keywords: Built Environment (BE); building operations; novel coronavirus; COVID-19; SARS-CoV-2
Online: 12 March 2020 (04:18:26 CET)
With the increasing spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that results in coronavirus disease 19 (COVID-19), corporate entities, federal, state, county and city governments, universities, school districts, health care facilities, assisted living organizations, daycares, homeowners, and other building owners and occupants have an opportunity to reduce the potential for transmission through built environment (BE) mediated pathways. Over the last decade, substantial research into the presence, abundance, diversity, function, and transmission of microbes in the BE has taken place and revealed common pathogen exchange pathways and In this paper, we synthesize this microbiology of the BE research and the known information about SARS-CoV-2 to provide actionable and achievable guidance to BE decision makers, building operators, and all indoor occupants attempting to minimize infectious disease transmission through environmentally mediated pathways. We believe this information will be useful to corporate and public administrators and individuals responsible for building operations and environmental services in their decision-making process about whether to implement social- distancing measures and for what
Tue, 17 March 2020
ARTICLE | doi:10.20944/preprints202003.0267.v1
Subject: Chemistry, Physical Chemistry Keywords: COVID-19; SARS-CoV-2; RNA-dependent RNA polymerase (RdRp); remdesivir; homology model; molecular dynamics; free energy perturbation
Online: 17 March 2020 (04:07:15 CET)
Starting from December 2019, coronavirus disease 2019 (COVID-19) has emerged as a once-in-a-century pandemic with deadly consequences, which urgently calls for new treatments, cures and supporting apparatuses. Remdesivir was reported by World Health Organization (WHO) as the most promising drug currently available for the treatment of COVID-19. Here, we use molecular dynamics simulations and free energy perturbation methods to study the inhibition mechanism of remdesivir to its target SARS-CoV-2 virus RNA-dependent RNA polymerase (RdRp). In the absence of a crystal structure of the SARS-CoV-2 RdRp, we first construct the homology model of this polymerase based on a previously available structure of SARS-CoV NSP12 RdRp (with a sequence identify of 95.8%). We then build the putative binding mode by aligning the remdesivir + RdRp complex to the ATP bound poliovirus RdRp. The putative binding structure is further optimized with molecular dynamics simulations and demonstrated to be stable, indicating a reasonable binding mode for remdesivir. The relative binding free energy of remdesivir is calculated to be -8.28 ± 0.65 kcal/mol, much stronger than the natural substrate ATP (-4.14 ± 0.89 kcal/mol) which is needed for the polymerization. The ~800-fold improvement in the Kd from remdesivir over ATP indicates an effective replacement of APT in blocking of the RdRp binding pocket. Key residues D618, S549 and R555 are found to be the contributors to the binding affinity of remdesivir. These findings demonstrate that remdesivir can potentially act as a SARS-CoV-2 RNA-chain terminator, effectively stopping its RNA reproduction, with key residues also identified for future lead optimization and/or drug resistance studies.
Wed, 19 October 2016
ARTICLE | doi:10.20944/preprints201610.0078.v1
Subject: Earth Sciences, Environmental Sciences Keywords: calibration; validation; optical; instrument; processing; imagery; spatial; operational
Online: 19 October 2016 (10:59:29 CEST)
As part of the Copernicus programme of the European Union (EU), the European Space Agency (ESA) has developed and is currently operating the Sentinel-2 mission that is acquiring high spatial resolution optical imagery. This paper provides a description of the calibration activities and the current status of the mission products validation activities. Measured performances, from the validation activities, cover both Top-Of-Atmosphere (TOA) and Bottom-Of-Atmosphere (BOA) products. Results presented in this paper show the good quality of the mission products both in terms of radiometry and geometry and provide an overview on next mission steps related to data quality aspects.
Thu, 7 May 2020
COMMUNICATION | doi:10.20944/preprints202005.0126.v1
Online: 7 May 2020 (13:20:42 CEST)
Evidence for the potential for airborne transmission of SARS-CoV-19 continues to accumulate, with important implications for healthcare workers, as well as the general public. Three lines of evidence support this conclusion.
Wed, 19 April 2017
ARTICLE | doi:10.20944/preprints201704.0124.v1
Online: 19 April 2017 (11:53:38 CEST)
A fluid flowing over an object has a tendency to drag the object along it’s flow direction. An object passing through a fluid which is stationary there is a tendency to slow the object down. For a stationary object in a fluid which is flowing there is a tendency to move the object in the fluid flowing direction .These tendencies of flowing fluid is known as drag. While moving through air airplanes also subjected to several drags. Airplanes subjected to pressure drag or form drag due to flow separation which is based on the pressure difference between the upstream and downstream surfaces of the object. Airplanes also subjected to Skin friction drag which results from the viscous shear of the fluid flowing over the object surface. In order to overcome these drags airplane wings cross section airfoils are designed very carefully. National Advisory Committee for Aeronautics, or NACA, developed and tested "families" of airfoils. Some of the most successful of these were the NACA four-digit and five-digit series. The necessary coordinates for designing NACA airfoil profiles are available in online. UIUC also provide coordinates for designing NACA airfoil profiles. But the present work describes the way of designing NACA four digit airfoils without taking any coordinates from available sources like google or any other search engines. Using C programming with the help of NACA provided equations a generalized source code is designed .Which will provide coordinates for designing any NACA four digit airfoil profiles .With the help of this obtained profile the wing model is also constructed using solid works. Using solid works model the real model was constructed using wood. The chord of regular surface airfoil is 21 cm and the span is also 21 cm. The airfoil profile taken for the model construction is NACA-4415 which is a four digit cambered airfoil.The present work also show some figures of an airfoil by applying certain surface modifications in form of dimples.
Thu, 3 November 2016
ARTICLE | doi:10.20944/preprints201611.0022.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: mixing time; LIF; CFD; SPH; stirred tank
Online: 3 November 2016 (09:22:18 CET)
Performing optimisation and scale-up studies of crystallisation systems requires accurate and computationally efficient mathematical models. The assumption of the ideal mixing conditions in batch reactors typically produce inaccurate results while the computational expense of CFD models is still prohibitively high. Therefore, in this work, a new intermediary approach is proposed that takes into account the non-ideal mixing conditions in the reactor and requires less computational resources than full CFD simulations. Starting with the Danckwerts concept of the intensity of segregation, an analogy between its application to chemical reactions and the kinetics of the crystallisation phenomena (such as nucleation and growth) has been made. As a result, the modified kinetics expressions have been derived which incorporate the effect of non-idealities present in stirred reactors. This way, based on the experimental measurements of the mixing time using the Laser Induced Fluorescence (LIF) technique, computationally more efficient mathematical models can be developed in two ways: (1) the accurate semi-empirical correlations are available for standard mixing configurations with the most often used types of impellers, (2) CFD simulations can be utilised for estimation of the mixing time; in this case it is necessary to simulate only the mixing process. The benefits offered by the LIF experimental technique have been demonstrated and some frequent problems in its application analysed. The mixing time results for configurations with and without baffles for three types of impellers and four different rotational speeds have been presented. The false shorter mixing times in the non-baffled configurations have been observed and this phenomena explained by the existence of two segregated zones in the reactor and confirmed by additional experiments. The precise measurements in these cases have been shown as difficult using the LIF technique, particularly for higher rpms. The experimental data has been compared to the preliminary simulation results obtained from the Smoothed Particle Hydrodynamics method and the standard k-ε turbulence model with the modest success. The shortcomings of the SPH model have been recognized and the directions for the future work discussed.
Tue, 25 February 2020
Online: 25 February 2020 (11:38:47 CET)
Background: Coronavirus disease 2019 (COVID-19) is a new viral respiratory disease and whether pregnant women are at increased risk of infection is unknown. Viral pneumonia is an important indirect cause of maternal death. Little is known about the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy. Objective: To describe the clinical characteristics of COVID-19 in pregnancy and their newborn infant, and we sought to explored whether the SARS-CoV-2 can be intrauterine vertically transmitted. Study Design: The study was a case series study conducted in the obstetric ward of Tongji Hospital affiliated to Huazhong University of science and technology, Wuhan, China. Demographic, clinical, laboratory and radiological profiles of the SARS-CoV-2 infection case series. A systematic testing procedure for SARS-CoV-2 infection using oropharyngeal swab, placenta tissue, vaginal mucus, and breast milk of mothers. and oropharyngeal swab, umbilical cord blood, and serum of newborns was conducted. Results: We have conducted the most thorough virological assessment to date, and we include a longer clinical observation in mother-infant dyads during hospitalization. The clinical course and outcomes of three pregnant women who acquired SARS-CoV-2 infection late pregnancy are described in mother-infant dyads. Two had caesarean delivery in their third trimester. All patients showed an uneventful perinatal course, and a successful outcome. No infants became infected by vertical transmission or during delivery. Conclusion: No evidence to suggest the potential risk of intrauterine vertical transmission in the case series and further in-depth study is needed. Both the pregnancy woman and infant showed fewer adverse maternal and neonatal outcomes.
Wed, 31 August 2016
REVIEW | doi:10.20944/preprints201608.0236.v1
Subject: Earth Sciences, Environmental Sciences Keywords: noise pollution; mechanical wood industries; equipment; control
Online: 31 August 2016 (09:03:57 CEST)
High level of noise is a disturbance to the human environment. Noise in industries is also an occupational hazard because of its attendant effects on workers’ health. Noise presents health and social problems in industrial operations, and the source is related to the machineries used in the industries. One of the unique features of the noise associated with wood machinery is the level of exposure and duration. Equipment used in a factory can be extremely loud. They can produce noise at decibels high enough to cause environmental health and safety concerns. The mechanically driven transport and handling equipment, cutting, milling, shaping and dust extractor installations in the wood industry generate noise. The sources of noise pollution have increased due to non-compliance with basic safety practices. The increased use of locally fabricated machine in the industry has increased the level of noise and vibration. The effects of industrial noise pollution as discussed include: increase in blood pressure; increased stress; fatigue; vertigo; headaches; sleep disturbance; annoyance; speech problems; dysgraphia, which means reading/learning impairment; aggression; anxiety and withdrawal. As presented in this paper, noise control techniques include; sound insulation, sound absorption, vibration damping and Vibration isolation.
Fri, 20 March 2020
ARTICLE | doi:10.20944/preprints202003.0302.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: COVID-2019; SARS-CoV-2; 2019-nCoV; repositioning; UPR/Autophagy; real-world evidence; pathways
Online: 20 March 2020 (03:55:55 CET)
More than 179,000 individuals have fallen ill of the Coronavirus disease (COVID-19) caused by the SARS-CoV-2 virus, which first emerged in China less than four months ago in December 2019. As of today, there exist no approved treatments against COVID-19. Vaccines are being developed, but they will take time, at least one year, to reach the population. Drug repositioning represents a fast track because already approved medicines have been broadly tested through multiple trials. We developed a repositioning strategy that mostly leads to candidates that are commonly used. The advantages are that they will facilitate proof of concept in humans through a “real-world evidence” approach and should be rapidly available to the population. We focus on the established research results that the unfolded protein response (UPR) and autophagy pathways of the host cells are essential to the life cycle of previously known coronaviruses. We performed the relevant bioinformatics analysis to understand and confirm if SARS-CoV-2 may interact with these druggable pathways. Based on these considerations, we prioritized two additional druggable pathways, which are important to the viral life cycle and tightly connected to UPR/autophagy signaling: the mitochondrial permeability transition pores (MPTP) and NLRP-3 inflammasome pathways. These four important pathways are perturbed in most major common diseases and have therefore been targeted by numerous broadly prescribed drugs. We have identified 97 approved drugs that are known to modulate these four identified pathways, and which represent, therefore, interesting repositioning candidates. Although it is indisputable that these drugs should never be used for immediate self-medication against COVID-19, we notice that some of them could also be prescribed to individuals who have COVID-19 comorbidities (e.g., hypertension). It is debated if these comorbidities are linked to the pathology itself (e.g., hypertension) or the drugs used to treat the pathology (e.g., sartans). Therefore, relevant preclinical tests and massive electronic health records (i.e., real-world evidence) must be used to pre-screen them and check the COVID-19 prognosis of individuals taking these drugs.
Sun, 28 June 2020
REVIEW | doi:10.20944/preprints202006.0336.v1
Online: 28 June 2020 (10:07:58 CEST)
The outbreak of Corona Virus effected negatively on the world’s economy which has already touched the maximum sectors. Readymade garments sector has the large contribution in Bangladesh’s economy. For increasing the locked down period, it is hitting badly by stopping production and cancellation of orders with some issues. This paper will represent the brief scenario and impacts of garments sector in recent days and the economy status of Bangladesh for the pandemic. The study is based on secondary data, collected from different authentic journals and web portals etc. Bangladesh’s garments earnings mostly depended on export but on these days, the buyers are cancelling their orders and the factories are being failed to give payments to the worker, some are being shut down also. As the duration of locked down is increasing, there is a huge chance to get unemployed and Bangladesh can be faced an undisciplined condition in near future. BGMEA and BKMEA are taking necessary steps to support the worker. Ensuring health security, the authorities are trying to reopen the factories limitedly to meet up the immediate needs. The government has taken the situation on most priority and introduce some improvement packages to run the economy smoothly and reduce the losses of the country for the pandemic.
Tue, 7 April 2020
REVIEW | doi:10.20944/preprints202004.0077.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: COVID-19; native American Indian; treatment; ACE2 receptor; pathophysiology; virulence
Online: 7 April 2020 (02:40:24 CEST)
Background: On Dec 19, 2019 it was reported by the public health department of China that an outbreak of pneumonia was caused by a novel Coronavirus. The virulence of the new virus COVID-19 was much greater than either the SARs or MERSs viruses and on March 11, 2020 the World Health Department (WHO) declared world -wide pandemic. Understanding the pathophysiology of virulence of the COVID-19 virus is absolutely necessary in understanding the transmission, virulence factors, reduce risk factors, clinical presentation, predict outcomes of the disease and provide guidance to any current or future treatment protocols. Methodology: A PubMed search was performed utilizing the words: Wuhan Virus, COVID-19, SARs coronavirus, ACE2, S protein, virulence, clinical presentation, epidemiology, genome, treatment, structure, MERs, pathogenesis and/or pathology alone and in combination with other terms. Each paper was evaluated by three content experts for quality, reproducibility, credibility and reputation of the journal. Results: The COVID-19 virus is much more virulent than either the SARs or MERs virus and its ability to cause serious disease inversely corresponds to the person’s ability to produce T-cells which declines linearly with age. The ACE2 receptor binding site do not vary among different ethnic groups but do in expression levels. This variance in expression level may explain for different infectivity rates among men and women and predict and explain different susceptibilities to infection by different ethnic groups. Furthermore, by understanding the underlying pathophysiology one can explain and provide guidance to the clinical effectiveness of any treatment. Conclusions: The underlying pathophysiology of COVID-19 explains not only the virulence, and clinical presentation, but, explains at a molecular level the comorbidity risk factors such as hypertension, sex, and age. Ethnic and anatomic expression patterns of ACE-2 and associated pathophysiology suggests that Native Americans and Asians may be particularly susceptible to this disease.
Tue, 14 November 2017
REVIEW | doi:10.20944/preprints201711.0081.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: Marfan; connective tissue disease; irritable bowel syndrome; hernia
Online: 14 November 2017 (04:08:45 CET)
Symptoms attributed to the gastrointestinal manifestations of multi-system disorders play an important role in the long-term management of these conditions. Gastrointestinal complications of a variety of connective tissue disorders have been studied and there is an increased interest in the incidence and prevalence of these symptoms. Descriptions of the occurrence of gastrointestinal complications in Marfan syndrome have appeared infrequently in the medical literature. In this review article we focus on both structural and functional gastrointestinal pathology that may occur in patients with Marfan syndrome.
Mon, 30 March 2020
REVIEW | doi:10.20944/preprints202003.0235.v2
Subject: Medicine & Pharmacology, Nutrition Keywords: acute respiratory distress syndrome (ARDS); ascorbic acid; cathelicidin; coronavirus; COVID-19; cytokine storm; influenza; observational; pneumonia, prevention; respiratory tract infection; solar radiation; treatment; UVB; vitamin C; vitamin D
Online: 30 March 2020 (05:48:43 CEST)
The world is in the grips of the COVID-19 pandemic. Public health measures that can reduce the risk of infection and death in addition to quarantines are desperately needed. This article reviews the roles of vitamin D in reducing risk of respiratory tract infections, knowledge about the epidemiology of influenza and COVID-19, and how vitamin D supplementation might be a useful measure to reduce risk. Through several mechanisms, vitamin D can reduce risk of infections. Those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increase concentrations of anti-inflammatory cytokines. Several observational studies and clinical trials reported that vitamin D supplementation reduced risk of influenza, whereas others did not. Evidence supporting the role of vitamin D in reducing risk of COVID-19 includes that the outbreak occurred in winter, a time when 25-hydroxyvitamin D [25(OH)D] concentrations are lowest; that the number of cases in the Southern Hemisphere near the end of summer are low; that vitamin D deficiency has been found to contribute to acute respiratory distress syndrome, and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(OH)D concentration. To reduce risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40–60 ng/ml (100–150 nmol/l). For treatment of people who become infected with COVID-19, higher vitamin D3 doses might be useful. Randomized controlled trials and large population studies should be conducted to evaluate these recommendations.
Sat, 24 February 2018
ARTICLE | doi:10.20944/preprints201802.0151.v1
Subject: Biology, Plant Sciences Keywords: color tests; thin layer chromatography; chemotaxonomy; secondary metabolites; solvent system
Online: 24 February 2018 (08:28:11 CET)
Presence and identity of secondary metabolites are two of the main components of lichen taxonomy. Aromatic compounds formed via the acetyl-polymalonate pathway are the most studied lichen substances. In addition, compounds derived from the mevalonic acid pathway (e.g., terpenes and steroids) are sometimes detected in the medulla. However, their identity and value as diagnostic characters in the genus Usnea are yet poorly understood despite the fact that they were mentioned in several taxonomical papers. We conclude that i) aside from the previously recognized polyphenolic compounds, carbohydrates and steroids are also detected in the medulla of some Usnea species; ii) the use of sulfuric anisaldehyde reagent greatly improves the detection of terpenes, carbohydrates and steroids compared with the sulfuric acid reagent routinely used in thin layer chromatography; iii) among carbohydrates, we detected arabitol and sucrose in the medulla; iv) steroids and terpenes remain unidentified and deserve further investigations.
Tue, 31 October 2017
ARTICLE | doi:10.20944/preprints201710.0194.v1
Subject: Chemistry, Medicinal Chemistry Keywords: Africa; Terminalia brownii; antifungal extracts; Aspergillus, Nattrassia, Fusarium; triterpenoids; flavonoids; ellagitannins; stilbenes
Online: 31 October 2017 (09:54:35 CET)
Decoctions, macerations and fumigations of the stem bark and wood of Terminalia brownii Fresen. are used in traditional medicine for fungal infections and as pesticides on field crops and in traditional granaries in Sudan. In addition, T. brownii is commonly used for protecting wooden houses and furniture. Therefore, using agar disc diffusion and macrodilution methods, eight extracts of various polarities from the stem wood and bark were screened for their growth inhibitory effects against filamentous fungi commonly causing fruit, vegetable and grain decay, as well as infections in the immunocompromised host. Ethyl acetate extracts of the stem wood and bark gave the best antifungal activities, with MIC values of 250 µg/ml against Nattrassia mangiferae and Fusarium verticillioides, and 500 µg/ml against Aspergillus niger and Aspergillus flavus. Aqueous extracts gave almost as potent effects as the ethyl acetate extracts against the Aspergillus and Fusarium strains, and were slightly more active than the ethyl acetate extracts against Nattrassia mangiferae. Thin layer chromatography, RP-HPLC-DAD and tandem mass spectrometry (LC-MS/MS), were employed to identify the chemical constituents in the ethyl acetate fractions of the stem bark and wood. The stem bark and wood were found to have a similar qualitative composition of polyphenols and triterpenoids, but differed quantitatively from each other. The stilbene derivatives, cis- (3) and trans- (4) resveratrol-3-O-β-galloylglucoside, were identified for the first time in T. brownii. Moreover, methyl-(S)-flavogallonate (5), quercetin-7-β-O-di-glucoside (8), quercetin-7-O-galloyl-glucoside (10), naringenin-4`-methoxy-7-pyranoside (7), 5,6-dihydroxy-3`,4`,7-tri-methoxy flavone (12), gallagic acid dilactone (terminalin) (6), a corilagin derivative (9) and two oleanane type triterpenoids (1) and (2) were characterized. Our results justify the traditional uses of macerations and decoctions of T. brownii stem wood and bark for crop and wood protection and demonstrate that standardized extracts could have uses for the eco-friendly control of plant pathogenic fungi in African agroforestry systems. Likewise, our results justify the traditional uses of these preparations for the treatment of skin infections caused by filamentous fungi.
Sat, 13 August 2016
ARTICLE | doi:10.20944/preprints201608.0136.v1
Subject: Engineering, Energy & Fuel Technology Keywords: vertical axis wind turbine; CST parameterization; NSGA-II; airfoil; optimization; multiple streamtube model
Online: 13 August 2016 (09:15:42 CEST)
Optimizing the NACA0015 airfoil which is widely applied in small-scale vertical axis wind turbine to make it has a better aerodynamic performance. In the optimization process, using CST parameterization method to perturb the airfoil geometry, the thickness and camber of the airfoil are selected as the constraint, and the value of the maximum tangential force coefficient is chosen as the objective function, the genetic algorithm based on non-dominated sorting (NSGA-II)is selected as an optimization method, calculates the aerodynamic performance of the airfoil by applying the approach of combining XFOIL program and Viterna-Corrigan post-stall mode ,and establishes the optimizing process by the optimization software modefrontier for NACA0015 airfoil’s muti-point optimization, validate the airfoil’s performance with CFD finally. The result illustrates that, by comparing with the NACA0015 airfoil, the optimized airfoil’s lift to drag ratio is improved over a wide range of attack angles, the stall performance is more gentle. The maximum lift coefficient, the maximum lift-drag ratio and the maximum tangential force coefficient are increased by 7.5%,9 and 8.87%, respectively. The optimized airfoil has a wide variable condition performance, more suitable for the operating conditions of a vertical axis wind turbine. Finally, predict the rotor efficiency with optimized airfoil and NACA0015 airfoil for different tip speed ratios and different solidities with multiple streamtube model, the result shows the rotor with optimized airfoil has a higher efficiency.
Tue, 22 May 2018
ARTICLE | doi:10.20944/preprints201805.0309.v1
Subject: Engineering, Construction Keywords: Acoustic design; Reverberation time; Clarity; Lateral fraction; Acoustic measurements; Classical concert hall
Online: 22 May 2018 (13:49:31 CEST)
This study aims at an acoustic design of the classical concert hall and evaluation of the acoustic performance. In terms of three acoustic parameters (i.e., reverberation time (RT), clarity (C80), and lateral fraction (LF)), this study performed acoustic simulation modeling and site measurement with the K Art Hall located in South Korea as a case study. First, in order to meet the acoustic performance of the K Art Hall (target RT: 1.4~1.7 seconds, target C80: -2dB or more +2dB or less, and target LF: 10~35%), the finish materials and shape of the room as an interior acoustic design were determined. Second, the average values of the RT, C80, and LF using the acoustic simulation modeling were estimated at 1.4 second, 1.2~1.6 dB, and 29%, respectively. Third, the average values of the RT, C80, and LF through site measuring were measured at 1.5~1.64 second, 0.07~1.31dB, and 22.22~31.37%, respectively. Thus, the results of both the acoustic simulation modeling and site measuring were analyzed so as to satisfy the target acoustic performance. The results of this study will help the decision-makers (i.e., owner, construction managers, etc.) to plan the classical concert hall in terms of the RT, C80, and LF.
Wed, 26 February 2020
Subject: Medicine & Pharmacology, Allergology Keywords: Coronavirus; SARS-CoV-2; COVID-19; Thalidomide; pneumonia
Online: 26 February 2020 (12:31:47 CET)
A novel coronavirus strain (severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first appeared in December 2019 and can cause acute respiratory distress syndrome and death. However, there are only limited therapy choices and no vaccine for SARS-CoV-2 is currently available. Here we report about a case of a SARS-CoV-2 caused pneumonia successfully treated with thalidomide. Thalidomide is an immunomodulatory and anti-inflammatory agent and was combined with a low-dose glucocorticoid. We suggest, that the effects of thalidomide might be related to regulating immunity, inhibiting the inflammatory cytokine surge, alleviating anxiety to reduce oxygen consumption, relieving vomit and lung exudation.
Wed, 6 January 2021
CASE REPORT | doi:10.20944/preprints202101.0132.v1
Online: 6 January 2021 (20:38:36 CET)
To date, uncertainty remains about how long the protective immune responses against SARS-CoV-2 persists and the first reports of suspected reinfection began to be described in recovered patients months after the first episode. Viral evolution may favor reinfections, and the recently described spike mutations, particularly in the receptor binding domain (RBD) in SARS-CoV-2 lineages circulating in the UK, South Africa, and most recently in Brazil, have raised concern on their potential impact in infectivity and immune escape. We report the first case of reinfection from genetically distinct SARS-CoV-2 lineage presenting the E484K spike mutation in Brazil, a variant associated with escape from neutralizing antibodies.
Thu, 12 March 2020
ARTICLE | doi:10.20944/preprints202003.0206.v1
Subject: Medicine & Pharmacology, Other Keywords: 2019 novel coronavirus infection; coronavirus; SARS-CoV; interferon; systems biology
Online: 12 March 2020 (09:11:00 CET)
As the outbreak of COVID-19 has accelerated, an urgent need for finding strategies to combat the virus is growing. Thus, gaining more knowledge on the pathogenicity mechanism of SARS-CoV-2, the causing agent of COVID-19, and its interaction with the immune system is of utmost importance. Although this novel virus is not well known yet, its structural and genetic similarity with SARS-CoV as well as the comparable pattern of age-mortality relations suggest that the previous findings on SARS can be applicable for COVID-19. Therefore, a systems biology study was conducted to investigate the underlying mechanism for the differences in the age-specific mortality of SARS and the most important signaling pathways activated by the virus. The results were then validated through a literature review on COVID-19 and the other closely related viruses, SARS and MERS. Interferons have shown to possess a crucial role in the defense against coronavirus diseases. The virus can impede the interferon induction in humans. Moreover, STAT1, a key protein in the interferon mediated immune response, is antagonized by the virus. This could explain the increased response threshold of immune cells to IFNs during CoV infections. A vivid correlation between the innate immune response threshold and the fatality rates in COVID-19 can be found. Differences in the dynamics of the interferons-related innate immune responses in children, adults and elderly may explain the reported fatality rates. The increased mortality rates in the elderly can be explained by the higher threshold of interferon-mediated immune responses. Earlier induction of interferons in children and their less developed immune system could be the reason behind their zero or near to zero fatality rate. Administration of interferon-inducing agents, such as Poly (ICLC), could reduce the mortality of SARS at the very early stages of the disease. Adding interferon-γ to an interferon-I, as a synergistic combination therapy, might maximize the benefits.At the later stages of the disease, however, the balance of the immune reactions would be disrupted and the responses would shift toward immnopathogenic over-reactions and probably cytokine storm. Moderating the activity of the immune system and supportive care in such conditions might be the optimum approach.
Tue, 18 April 2017
REVIEW | doi:10.20944/preprints201704.0109.v1
Subject: Engineering, Other Keywords: fiber ring laser; hybrid mode locking; passive mode locking; rational harmonic mode locking; pulse compression
Online: 18 April 2017 (05:14:55 CEST)
Mode locked pulse generation has been reported using both active and passive mode locking schemes. Active mode locking technique has been proven to be an effective way to generate high-repetition-rate pulses by incorporating a modulator inside the laser cavity. Compared to actively mode locked lasers, passively mode locked lasers can generate pulse train at ultrashort pulse width but with relatively lower repetition rate. Thus, it is a brilliant idea to build a hybrid mode locked system combining both active and passive mode lockers. In this review, several hybrid mode locked fiber ring laser systems are discussed and summarized. Hybrid mode locking is a promising method to generate high speed ultrashort optical pulses for fiber-optic telecommunication system.
Tue, 24 March 2020
ARTICLE | doi:10.20944/preprints202003.0356.v1
Subject: Life Sciences, Genetics Keywords: COVID-19; SARS-CoV-2; host genetics; genetics; polygenic risk score
Online: 24 March 2020 (08:36:20 CET)
The global pandemic of COVID-19 accounts for more than 14,000 deaths worldwide. However, little is known about the host genetics interaction with infection and COVID-19 progression. To better understand the role of host genetics, we review the current literature, aggregate readily available genetic resources, and provide some updated analysis relevant to COVID-19 and associated phenotypes. Using the unrelated individuals in UK Biobank (total n = 337,579 across 5 populations), we aggregate human leukocyte antigen and ABO blood type frequencies. We find significant and consistent risk reduction of blood group O reported in Zhao et al. and encourage broad sharing of ABO blood type frequencies that are readily accessible across COVID-19 with mild, moderate, and severe/critical symptoms for robust inferences at https://tinyurl.com/abo-covid19. In addition, we generate polygenic risk scores (PRSs) weights for 29 blood measurements, including clinically relevant haematological measurements for COVID-19, such as lymphocyte count and percentage. Focusing on the 8 most COVID-19 clinically relevant blood measurements, we performed PRS-PheWAS analysis across 44 disease antigen measurements (n = 6,643 unrelated individuals in White British group), infectious diseases and acute respiratory infections (n = 20,928 cases and 349,000 controls across 3 population groups) and deaths (n = 1,846 cases and 368,082 controls), recorded in hospital inpatient record and death registry data, respectively, in UK Biobank, and find host genetic PRS associations with disease risk. Taken together, we anticipate these resources (https://github.com/rivas-lab/covid19) will aid in improving our understanding of host genetic risk factors playing a role in SARS-CoV-2 infection and COVID-19 disease severity.
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