Molecular dynamics simulation of interaction between nanorod and phospholipid molecules bilayer

Natural and artificially prepared nanorods' surfaces have proved to have good bactericidal effect and self-cleaning property. In order to investigate whether nanorods can kill the enveloped virus, like destroying bacterial cell, we study the interaction between nanorods and virus envelope by establishing the models of nanorods with different sizes as well as the planar membrane and vesicle under the Dry Martini force field of molecular dynamics simulation. The results show that owing to the van der Waals attraction between nanorods and the tail hydrocarbon chain groups of phospholipid molecules, the phospholipid molecules on virus envelope are adsorbed to nanorods on a large scale. This process will increase the surface tension of lipid membrane and reduce the order of lipid molecules, resulting in irreparable damage to planar lipid membrane. Nanorods with different diameters have different effects on vesicle envelope, the larger the diameter of nanorod, the weaker the van der Waals effect on the unit cross-sectional area is and the smaller the degree of vesicle deformation. There is synergy between the nanorods in the nanorod array, which can enhance the speed and scale of lipid adsorption. The vesicle adsorbed in the array are difficult to desorb, and even if desorbed, vesicle will be seriously damaged. The deformation rate of the vesicle adsorbed in the nanorod array exceeds 100%, implying that the nanorod array has a strong destructive effect on the vesicle. This preliminarily proves the feasibility of nanorod array on a surface against enveloped virus, and provides a reference for the design of corresponding nanorods surface.

[A randomized controlled trial study of immunogenicity and safety of an inactivated SARS-CoV-2 vaccine in different immunization schedules].

Objective: To compare the immunogenicity and safety of an inactivated SARS-CoV-2 vaccine used for the vaccination in public security officers with different immunization schedules. Methods: From January to February, 2021, 405 public security officers in Taiyuan were randomly divided into 3 groups. Two doses of SARS-CoV-2 inactivated vaccine were injected according to the immunization schedule of 0-14 days, 0-21 days or 0-28 days, respectively. The nucleic acid of SARS-CoV-2 was detected by reverse transcription polymerase chain reaction. The neutralizing antibodies to SARS-CoV-2 were tested by microdose cytopathogenic efficiency assay of live virus. The GMT, seroconversion rate of SARS-CoV-2 neutralizing antibody and safety of the vaccine were analyzed for the 3 groups. Results: The seroconversion rate of SARS-CoV-2 neutralizing antibody was 100% in all the 3 groups. The SARS-CoV-2 neutralizing antibody level of 0-21 day group [166.70 (95%CI: 148.30-185.10)] was similar to that of 0-28 day group [179.50 (95%CI: 156.50-202.60)] (P>0.05), significantly higher than that of 0-14 day group [86.08 (95%CI: 72.36-99.80)] (P<0.001). The incidence rates of adverse reaction in the 3 groups were 1.48% (2/135), 0.74% (1/136) and 1.49% (2/134) respectively (P=0.750), all the adverse reactions were mild. Conclusions: The vaccination of inactivated SARS-CoV-2 vaccine with different immunization schedules in public security officers showed good safety and high seroconversion rate, and the GMTs of SARS-CoV-2 neutralizing antibody in 0-21 day group and 0-28 day group were higher than that in 0-14 day group.

Evaluation of the occurrence of psychotropic drugs in urban sewage and the abuse during the COVID-19 epidemic period in a city of Guangdong

Wastewater-based epidemiology was applied to study the impact of the COVID-19 in 2020 on occurrence and consumption of methamphetamine and ketamine before, during, and after the outbreak in a city of Guangdong province. To estimate the total consumption during the outbreak, mobile data of the city was used to study the dynamics of the population in the towns and districts of the city. The concept of composite population was brought about for the first time and calculated to estimate total drug consumptions of each towns or districts. The population during the outbreak decreased by about 45% relative to before the outbreak. The total consumptions of the two drugs declined by about 75% during the outbreak relative to before the outbreak. However, the decrease to this extent rather implies the persistence of abuse of the two drugs, given the extremely strict control measures. The consumptions of the two drugs were found to decrease by approximately 50% relative to before the outbreak. The consumptions of the drugs rebounded to the level before the outbreak, further demonstrating the persistence of the abuse. © 2021, Editorial Board of China Environmental Science. All right reserved.

[Comparison of epidemic characteristics between SARS in 2003 and COVID-19 in 2020 in Guangzhou].

Objective: By analyzing the epidemic characteristics and related indicators of SARS and COVID-19, to explore the reasons for the similarities and differences of the two epidemics, so as to provide reference for epidemic prevention and control. Methods: The general situation, clinical classification, activity history, contact history, family members' contact and incidence of the two infectious diseases in Guangzhou were collected and used to analyze the time characteristics, occupational characteristics, age characteristics and other key indicators of the two diseases, including the number of cases, composition ratio (%), mean, median, crude mortality, etc. Results: A total of 1 072 cases of SARS were included in the study. Three hundred and fifty three were severe cases with the incidence of 30.13%. Forty three cases of death were reported with a mortality rate of 4.01%. The average age was 46 years old, and 26.31% of the cases were medical staff. The interval time between first report to continuous zero reports was 129 days. As to COVID-19, a total of 346 cases were included. 58 of which were severe cases with the incidence of 16.67%. One case of death was reported with a mortality rate of 0.29%. The average age was 38 years old, and no hospital infection among medical staff was reported. The interval time between first report to continuous zero reports was 35 days. Conclusions: The prevention and control strategies for COVID-19 were more effective compared to that of SARS, and the emergency response procedures were worth to be evaluated and summarized.