ABSTRACT
HIV-1 reverse transcriptase (RT) inhibitors play essential role in anti-HIV therapy. The vast majority of them target the enzymes, while very few are able to bind to the viral RNA. Here we designed and synthesized two new terpyridyl Ru(II) complexes with HIV-1 TAR RNA binding groups. The complex RuTz2 exhibited a remarkable selectivity for poly(A) RNA over calf thymus DNA, total RNA and yeast transfer RNA, generated significant visible spectral response and inhibited the reverse transcription of poly(A) RNA to poly(dT) cDNA by M-MuLV RT. Moreover, RuTz2 was found to target the HIV-1 TAR RNA tightly and selectively by molecular recognition of hydrogen bonds, further stabilize the Ru(II)-RNA binding complex by electrostatic attraction, and efficiently inhibit the HIV-1 RT. These terpyridyl Ru(II) complexes also showed low toxicity to normal cells, which would greatly reduce its harmful side-effect on normal cells in drug application. This work also provides valuable drug design strategies for AIDS and other RT related diseases researches, such as HCV, EBOV and SARS-CoV-2.
ABSTRACT
Novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-COV-2) is spreading rapidly around the world and has become a global pandemic. Meteorological factors have been recognized as one of the critical factors that influence the epidemiology and transmission of infectious diseases. In this context, the World Meteorological Organization and scholars at home and abroad have paid extensive attention to the relationships of environment and meteorology with COVID-19. This paper systematically collected and sorted out relevant domestic and foreign studies, and reviewed the latest research progress on the impact of environmental and meteorological factors on COVID-19, classifying them into typical meteorological factors (such as temperature, humidity, and wind speed), local environmental factors (such as indoor enclosed environment, ventilation, disinfection, and air conditioning), and air pollution. Current research evidence suggests that typical meteorological factors, local environmental factors, and air pollutants are closely related to the transmission of COVID-19. However, the results of different studies are still divergent due to uncertainty about the influencing mechanism, and differences in research areas and methods. This review elucidated the importance of environmental and meteorological factors to the spread of COVID-19, and provided useful implications for the control of further large-scale transmission of COVID-19 and the development of prevention and control strategies under different environmental and meteorological conditions.
ABSTRACT
Objective To study the the inhibitory effect of baicalin on novel Coronavirus (2019-NCOV) entry process in vitro. Methods The pseudovirus system of SARS-CoV-2 S protein constructed with luciferase reporter gene was used in the study. A luciferase kit was used to detect the changes of luciferase expression in Huh-7 cells, and then the virus inhibition curve was plotted. Results Baicalin can significantly inhibited the infection rate of pseudovirus. There was no significant difference in the virus inhibition curve between the baicalin&virus pre-incubation group and co-incubation at different concentrations, indicating that baicalin could not directly bind to virus, but inhibited the virus S protein mediated cell fusion process. We futher found that, the inhibition rate of baicalin to virus decreased significantly in the 4h group, but had no significant difference in the 0h and 2h groups at the concentration of 0.125mg/ mL, indicating that baicalin may have an inhibitory effect on virus invasion stage rather than adsorption stage, and the mediated inhibition stage occurred within 4h. Conclusion Baicalin may mediate the fusion of SARS-CoV-2 S protein with cell surface receptor and exert anti-novel coronavirus activity by playing a role in inhibitting virus invasion in non-adsorption stage.
ABSTRACT
In recent years, people from all over the world are suffering from one of the most severe diseases in history, known as Coronavirus disease 2019, COVID-19 for short. When the virus reaches the lungs, it has a higher probability to cause lung pneumonia and sepsis. X-ray image is a powerful tool in identifying the typical features of the infection for COVID-19 patients. The radiologists and pathologists observe that ground-glass opacity appears in the chest X-ray for infected patient \cite{cozzi2021ground}, and it could be used as one of the criteria during the diagnosis process. In the past few years, deep learning has proven to be one of the most powerful methods in the field of image classification. Due to significant differences in Chest X-Ray between normal and infected people \cite{rousan2020chest}, deep models could be used to identify the presence of the disease given a patient's Chest X-Ray. Many deep models are complex, and it evolves with lots of input parameters. Designers sometimes struggle with the tuning process for deep models, especially when they build up the model from scratch. Genetic Algorithm, inspired by the biological evolution process, plays a key role in solving such complex problems. In this paper, I proposed a genetic-based approach to optimize the Convolutional Neural Network(CNN) for the Chest X-Ray classification task.
Subject(s)
COVID-19ABSTRACT
Abstract COVID-19 is spreading rapidly worldwide, posing great threats to public health and economy. This study aims to examine how the transmission of COVID-19 is modulated by climate conditions, which is of great importance for better understanding of the seasonal feature of COVID-19. Constrained by the accurate observations we can make, the basic reproduction numbers (R0) for each country were inferred and linked to temperature and relative humidity (RH) with statistical analysis. Using R0 as the measure of COVID-19 transmission potential, we find stronger transmission of COVID-19 under mildly warm (0°C?< T <?20°C) and humid (RH?>?60%) climate conditions, while extremely low (T <??2°C) and high (T >?20°C) temperature or a dry climate (RH?<?60%) weakens transmission. The established nonlinear relationships between COVID-19 transmission and climate conditions suggest that seasonal climate variability may affect the spread and severity of COVID-19 infection, and temperate coastal regions with mildly warm and humid climate would be susceptible to large-scale outbreaks.
ABSTRACT
BackgroundHigh prevalence of myopia of adolescent has been a global public health concern. Their risk factors and effective prevention methods for myopia across schoolchildren developmental stages are critically needed but remain uncertain due to the difficulty in implementing intervention measurements under normal life situation. We aimed to study the impact of the COVID-19 quarantine on myopia development among over one-million schoolchildren. MethodsWe designed the ongoing longitudinal project of Myopic Epidemiology and Intervention Study (MEIS) to biannually examine myopia among millions of schoolchildren for ten years in Wenzhou City, Zhejiang Province, China. In the present study, we performed three examinations of myopia in 1,305 elementary and high schools for schoolchildren in June 2019, December 2019 and June 2020. We used the normal period (June-December 2019) and COVID-19 quarantine period (January-June 2020) for comparisons. Myopia was defined as an uncorrected visual acuity of 20/25 or less and a spherical equivalent refraction (SER) of -0.5 diopters (D) or less. High myopia was defined as an SER of -6.0 D or less. FindingsIn June 2019, 1,001,749 students aged 7-18 were eligible for examinations. In the 6-month and 12-month follow-up studies, there were 813,755 eligible students (81.2%) and 768,492 eligible students (76.7%), respectively. Among all students, we found that half-year myopia progression increased approximate 1.5 times from -0.263 D (95% CI, -0.262 to -0.264) during normal period to -0.39 D (95% CI, -0.389 to -0.391) during COVID-19 quarantine (P < 0.001). Multivariate Cox regression analysis identified grade rather than age was significantly associated with myopia (Hazard ratio [HR]: 1.10, 95% CI, 1.08 to 1.13; P < 0.001) and high myopia (HR: 1.40, 95% CI, 1.35 to 1.46; P < 0.001) after adjustment for other factors. The prevalence, progression, and incidence of myopia and high myopia could be categorized into two grade groups: I (grades 1-6) and II (grades 7-12). Specifically, COVID-19 quarantine for 6 months sufficiently increased risk of developing myopia (OR: 1.36, 95% CI, 1.33 to 1.40) or high myopia (OR: 1.30, 95% CI, 1.22 to 1.39) in Grade Group I, but decreased risk of developing myopia (OR: 0.45, 95% CI, 0.43 to 0.48) or high myopia (OR: 0.57, 95% CI, 0.54 to 0.59) in Grade Group II. InterpretationThe finding that behavioral modifications for six months during COVID-19 quarantine sufficiently and grade-specifically modify myopia development offers the largest human behavioral intervention data at the one million scale to identify the grade-specific causal factors and effective prevention methods for guiding the formulation of myopia prevention and control policies. FundingKey Program of National Natural Science Foundation of China; the National Natural Science Foundation of China; Scientific Research Foundation for Talents of Wenzhou Medical University; Key Research and Development Program of Zhejiang Province. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSMyopia is the most-common refractive error worldwide. Myopia with younger onset may result in developing high myopia, which is associated with sight-threatening ocular diseases such as maculopathy, retinal detachment, opticneuropathy, glaucoma, retinal atrophy, choroidal neovascularization. In light of the increasing prevalence of myopia and high myopia has been a global public health concern, the impact of COVID-19 lockdown on myopia development has gained substantial attention. We searched PubMed, Google Scholar, and MEDLINE databases for original articles reported between database inception and November 10, 2020, using the following search terms: (coronavirus OR COVID* OR SARS-COV-2 OR lockdown OR quarantine) AND (myopia OR short-sightedness OR refractive error). To date, there was no original study reported to uncover the influence of COVID-19 quarantine on myopia progression. Added value of this studyThis study provides the largest longitudinal intervention data on myopia progression in Chinese schoolchildren covering all grades of schoolchildren at one-million scale. COVID-19 quarantine model uncovers that behavioral modifications for six months may lead to significant increase of overall prevalence of myopia associated with their increased screen times and decreased outdoor activity times. Importantly, their effects on developing myopia or high myopia of students are grade-dependent, which were risk factors for elementary schools period but protective factors for high schools period partly due to reduced school education burden. Implications of all the available evidenceThis one-million schoolchildren myopia survey offers evidence that six months behavioral modifications sufficiently and grade-specifically change the progression of myopia and high myopia. In view of the increased use of electronic devices is an unavoidable trend, effective myopia prevention strategy according to grade among students is urgently needed. Since COVID-19 outbreak is still ongoing and spreading, international collaborate efforts are warranted to uncover the influence of COVID-19 on myopia progression to further substantiate these findings.