The effect of nuclear deformation on level statistics

We analyze the nearest neighbor spacing distributions of low-lying 2+ levels of even-even nuclei. We grouped the nuclei into classes defined by the quadrupole deformation parameter (Beta2). We calculate the nearest neighbor spacing distributions for each class. Then, we determine the chaoticity parameter for each class with the help of the Bayesian inference method. We compare these distributions to a formula that describes the transition to chaos by varying a tuning parameter. This parameter appears to depend in a non-trivial way on the nuclear deformation, and takes small values indicating regularity in strongly deformed nuclei and especially in those having an oblate deformation.Comment: 10 Pages, 6 figure

Scaffold hopping of α-rubromycin enables direct access to FDA-approved cromoglicic acid as a SARS-CoV-2 M^Pro inhibitor

The COVID-19 pandemic is still active around the globe despite the newly introduced vaccines. Hence, finding effective medications or repurposing available ones could offer great help during this serious situation. During our anti-COVID-19 investigation of microbial natural products (MNPs), we came across α-rubromycin, an antibiotic derived from Streptomyces collinus ATCC19743, which was able to suppress the catalytic activity (IC50 = 5.4 µM and Ki = 3.22 µM) of one of the viral key enzymes (i.e., MPro). However, it showed high cytotoxicity toward normal human fibroblasts (CC50 = 16.7 µM). To reduce the cytotoxicity of this microbial metabolite, we utilized a number of in silico tools (ensemble docking, molecular dynamics simulation, binding free energy calculation) to propose a novel scaffold having the main pharmacophoric features to inhibit MPro with better drug-like properties and reduced/minimal toxicity. Nevertheless, reaching this novel scaffold synthetically is a time-consuming process, particularly at this critical time. Instead, this scaffold was used as a template to explore similar molecules among the FDA-approved medications that share its main pharmacophoric features with the aid of pharmacophore-based virtual screening software. As a result, cromoglicic acid (aka cromolyn) was found to be the best hit, which, upon in vitro MPro testing, was 4.5 times more potent (IC50 = 1.1 µM and Ki = 0.68 µM) than α-rubromycin, with minimal cytotoxicity toward normal human fibroblasts (CC50 > 100 µM). This report highlights the potential of MNPs in providing unprecedented scaffolds with a wide range of therapeutic efficacy. It also revealed the importance of cheminformatics tools in speeding up the drug discovery process, which is extremely important in such a critical situation

Inhibitory activity of benzo[h]quinoline and benzo[h]chromene in human glioblastoma cells

Purpose: To carry out a neat synthesis of 2-amino-5,6-dihydro-8-methoxy-4-phenylbenzo[h]quinoline-3- carbonitrile (compound 2) and 2-amino-5,6-dihydro-8-methoxy-4-phenyl-4H-benzo[h]chromene-3- carbonitrile (compound 3) and evaluate their cytotoxic activity in human glioblastoma cells.Methods: Benzo[h]quinoline and benzo[h]chromene were synthesized by treating 6-methoxy-1- tetralone with benzylidenemalononitrile under microwave irradiation. The structures of compounds 2 and 3 were confirmed by elemental, spectral, and x-ray crystallographic analyses. The cytotoxic activity of compounds 2 and 3 was evaluated using WST-1 assay in U373 human glioblastoma cell line.Results: The molecular structures of compounds 2 and 3 were demonstrated unambiguously from single crystal x-ray measurements and they crystallized in triclinic form, P-1, for both compounds. In vitro cytotoxic activity data for compound 2 in human glioblastoma cell line (U373) indicate that no significant cytotoxicity was observed. On the other hand, compound 3 showed highly significant cytotoxic effects on U373 cells at concentrations starting from 0.1 μg/ mL.Conclusion: Compound 3 produces a decrease in cell viability with approximately 80 % cell death while compound 2 did not indicate significant cytotoxic activity. This suggests that the chromene moiety of compound 3 may be responsible for its high cytotoxicity.Keywords: Hydronaphthaline, Benzo[h]quinolone, Benzo[h]chromene, X-ray crystallography, U373 human glioblastoma, Cytotoxicity, Chromene moiet

Prevalence and trends of transfusion transmissible infections among blood donors in the State of Qatar, 2013-2017.

Millions of lives around the world are being saved annually through blood transfusion. However, blood transfusion is among the essential vehicles for transmitting infections. The overall prevalence of Transfusion Transmissible Infections among blood donors differs around the world, reflecting the variation in the prevalence of these infections. This study aims to assess the prevalence and trends of Transfusion Transmissible Infections among blood donors in Qatar. This is a cross-sectional study utilizing donation records of 5 years from January 2013 to December 2017. We included in the study results for all screening and confirmatory tests for Hepatitis B Virus, Hepatitis C Virus, Human T-lymphotropic Virus-I/II, Syphilis and Malaria. Among the 190,509 donations received at the donation centre during the study period, about 91% of donations were received from males and 9% from females. The overall positivity rate for all tests was 1.87, 2.23, 1.78, 2.31, 2.67% for the years 2013 through 2017, with an increasing yearly trend by 6% each year. The overall positivity rates for Hepatitis C Virus, Human T-lymphotropic Virus-I/II, Hepatitis B Virus, Syphilis and Malaria (2013-2017) were 0.60, 0.18, 0.30, 0.43 and 0.20%, respectively. The overall positivity rate of all tests combined for the Transfusion Transmissible Infections demonstrated a gradually increasing trend from 2013 to 2017. However, the trend for each infection (Hepatitis C Virus, Hepatitis B Virus, Syphilis and Malaria) was fluctuating except for Human T-lymphotropic Virus-I/II, which was increasing. Supporting the development of effective prevention and control strategies requires further comprehensive investigations for better estimation of the burden of these infections.The authors gratefully acknowledge the Blood Donation Center at HMC for their support

Hydrogen-induced rupture of strained Si─O bonds in amorphous silicon dioxide

Using ab initio modeling we demonstrate that H atoms can break strained Si─O bonds in continuous amorphous silicon dioxide (a−SiO2) networks, resulting in a new defect consisting of a threefold-coordinated Si atom with an unpaired electron facing a hydroxyl group, adding to the density of dangling bond defects, such as E′ centers. The energy barriers to form this defect from interstitial H atoms range between 0.5 and 1.3 eV. This discovery of unexpected reactivity of atomic hydrogen may have significant implications for our understanding of processes in silica glass and nanoscaled silica, e.g., in porous low-permittivity insulators, and strained variants of a−SiO2

Demographics and Epidemiology of Hepatitis B in the State of Qatar: A Five-Year Surveillance-Based Incidence Study

Background: Expatriates represent >80% of Qatar’s population, mostly arriving from countries in Africa and Asia that are endemic with many diseases. This increases the risk for introducing new pathogens into the country and provides a platform for maintenance of endemic pathogen circulation. Here, we report on the incidence and epidemiological characteristics of hepatitis B in Qatar between 2010 and 2014. Methods: We performed a retrospective epidemiological data analysis using the data available at the surveillance system of the Ministry of Public Health (MOPH) in Qatar. Data were collected from distinctive public and private incorporates around the nation. Reported cases of hepatitis B patients represent those who met the stringent case definition as per World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) guidelines and eventually reported to MOPH. Results: The annual incidence rates of hepatitis B cases were 30.0, 34.2, 30.5, 39.4, and 19.8 per 100,000 population in 2010, 2011, 2012, 2013, and 2014, respectively. There was no specific trend or seasonality for the reported cases. The incidence rates were higher in females compared to males between 2010 and 2012, but similar in 2013 and 2014. The highest incidence rates were reported among individuals between 25 and 34 years of age. No cases were reported in children younger than five years in 2013 and 2014. Rates of hepatitis B cases declined dramatically in 2014, in both Qataris and non-Qataris, as compared to the previous years. Conclusion: Our results indicate a dramatic decline of hepatitis B cases in Qatar but mandate improved surveillance and vaccination efforts in expatriates in the nation. View Full-TextMOP

Decarboxylative and dehydrative coupling of dienoic acids and pentadienyl alcohols to form 1,3,6,8-tetraenes

Dienoic acids and pentadienyl alcohols are coupled in a decarboxylative and dehydrative manner at ambient temperature using Pd(0) catalysis to generate 1,3,6,8-tetraenes. Contrary to related decarboxylative coupling reactions, an anion-stabilizing group is not required adjacent to the carboxyl group. Of mechanistic importance, it appears that both the diene of the acid and the diene of the alcohol are required for this reaction. To further understand this reaction, substitutions at every unique position of both cou- pling partners was examined and two potential mechanisms are presented

The sample of choice for detecting Middle East respiratory syndrome coronavirus in asymptomatic dromedary camels using real-time reverse-transcription polymerase chain reaction

The newly identified Middle East respiratory syndrome coronavirus (MERS-CoV), which causes severe respiratory disease, particularly in people with comorbidities, requires further investigation. Studies in Qatar and elsewhere have provided evidence that dromedary camels are a reservoir for the virus, but the exact modes of transmission of MERS-CoV to humans remain unclear. In February 2014, an assessment was made of the suitability and sensitivity of different types of sample for the detection of MERS-CoV by real-time reverse-transcription polymerase chain reaction (RT-PCR) for three gene targets: UpE (upstream of the E gene), the N (nucleocapsid) gene and open reading frame (ORF) 1a. Fifty-three animals presented for slaughter were sampled. A high percentage of the sampled camels (79% [95% confidence interval 66.9-91.5%, standard error 0.0625]; 42 out of 53) were shown to be shedding MERS-CoV at the time of slaughter, yet all the animals were apparently healthy. Among the virus-positive animals, nasal swabs were most often positive (97.6%). Oral swabs were the second most frequently positive (35.7%), followed by rectal swabs (28.5%). In addition, the highest viral load, expressed as a cycle threshold (Ct) value of 11.27, was obtained from a nasal swab. These findings lead to the conclusion that nasal swabs are the candidate sample of choice for detecting MERS-CoV using RT-PCR technology in apparently healthy camels