Simulating potential outbreaks of Delta and Omicron variants based on contact-tracing data:A modelling study in Fujian Province,China

Although studies have compared the relative severity of Omicron and Delta variants by assessing the relative risks,there are still gaps in the knowledge of the potential COVID-19 burden these variations may cause.And the contact patterns in Fujian Province,China,have not been described.We identified 8969 transmission pairs in Fujian,China,by analyzing a contact-tracing database that recorded a SARS-CoV-2 outbreak in September 2021.We estimated the waning vaccine effectiveness against Delta variant infection,contact patterns,and epidemiology distributions,then simulated potential outbreaks of Delta and Omicron variants using a multi-group mathematical model.For instance,in the contact setting without stringent lockdowns,we estimated that in a potential Omicron wave,only 4.7%of infections would occur in Fujian Province among individuals aged>60 years.In comparison,58.75%of the death toll would occur in unvaccinated individuals aged>60 years.Compared with no strict lockdowns,combining school or factory closure alone reduced cumulative deaths of Delta and Omicron by 28.5%and 6.1%,respectively.In conclusion,this study validates the need for continuous mass immunization,especially among elderly aged over 60 years old.And it confirms that the effect of lockdowns alone in reducing infections or deaths is minimal.However,these measurements will still contribute to lowering peak daily incidence and delaying the epidemic,easing the healthcare system's burden.

Analysis of the effect of PCR testing and antigen testing on controlling the transmission for Omicron based on different scenarios

After the policy adjustment,China no longer carries out COVID-19 PCR testing for all people,and antigen testing has become the main way to detect and manage infectious sources.We developed a dynamic model to evaluate and compare the effects between PCR and antigen testing for controlling the pandemic.Due to the increase of contact degree,the peak reduction effect of PCR testing in population is lower than that of antigen testing.Even if it was only 20%of people isolated at home after antigen testing,the peak of the epidemic could be reduced by 9.46%.If the proportion of antigen testing is further increased to 80%,the peak of the pandemic can be reduced by 31.41%.Antigen testing performed better effects in school(reduction proportion 29.27%)and community(29.34%)than in workplace(27.75%).Therefore,we recommend that antigen testing in the popu-lation should be encouraged during the pandemic,and home isolation of infected persons should be advocated,especially in crowded places.To improve the availability of antigen,the testing proportion should be further enhanced.

Super stable CsPbBr3@SiO2 tumor imaging reagent by stress-response encapsulation

Great photoelectric properties can herald the high potentials of CsPbBr3 nanocrystals(NCs)to function as the fluorescent probes for early tumor diagnosis.However,the intrinsic water vulnerability of CsPbBr3 NCs highly restricts their biomedical applications.To conquer this challenge,we herein introduce a nature inspired"stress-response"method to tightly encapsulate CsPbBr3 into SiO2 nano-shells that can dramatically improve the water stability of CsPbBr3@SiO2 nanoparticles for over 48 h.We further highlighted the advantageous features of CsPbBr3@SiO2 by using them as the fluorescent probes for CT26 tumor cell imaging with their high water stability,biocompatibility,and low cytotoxicity.Our work for the first time exhibited the potential of lead halide perovskite NCs for tumor diagnosis,and can highly anticipate the further in vivo biomedical applications that light up live cells.

Genomic Characterization of a New Coronavirus from Migratory Birds in Jiangxi Province of China

Dear Editor,The emergence of COVID-19 since December 2019 has attracted great attention around the world and reminds the powerful pathogenic potential of viruses(Zhou et al.2020).The subfamily Orthocoronavirinae of the family Coronaviridae contains four genera Alphacoronavirus,Betacoronavirus,Gammacoronavirus,and Deltacoronavirus,which are the largest group of positive-sense,non-segmented,single-stranded,enveloped RNA viruses(Woo et al.2012;Shi et al.2016).The genus Gammacoronavirus currently has five species(https://talk.ictvonline.org/taxonomy/),which are primarily spread through birds(Woo et al.2012).

Preparation and Li-storage properties of SnSb/graphene hybrid nanostructure by a facile one-step solvothermal route

A SnSb nanocrystal/graphene hybrid nanocomposite was synthesized by a facile one-step solvothermal route using graphite oxide,SnCl_(2).2H_(2)O and SbCl_(3) as the starting materials,absolute ethanol as the solvent,and NaBH4 as the reductant.The formation of SnSb alloy and the reduction of the graphene oxide occur simultaneously.SnSb nanoparticles with a size of 30–40 nm were uniformly anchored and confined by the graphene sheets,forming a unique SnSb/graphene hybrid nanostructure.The electrostatic attraction between the positively charged ions(Sn^(2+) and Sb^(3+))and the negatively charged graphene oxide plays an important role in the uniform distribution of the SnSb particles on the graphene sheets.The electrochemical Li-storage properties of the nanocomposite were investigated as a potential high-capacity anode material for Li-ion batteries.The results show that the nanocomposite exhibits an obvious enhanced Li-storage performance compared with bare SnSb.The improvement of the electrochemical performance could be attributed to the formation of two-dimensional conductive networks,homogeneous dispersion and confinement of SnSb nanoparticles and the enhanced wetting of active material with the electrolyte for increased specific surface area by the introduction of graphene into SnSb nanoparticles.Li-ion chemical diffusion coefficient and ac impedance were measured to understand the underlying mechanism for the improved electrochemical performance.

Suspected Yellow Fever Case Determined to be Adverse Vaccine Reaction

Jiangxi Provincial Center for Disease Control and Prevention(Jiangxi CDC)received an alert at 23:45 on November 7,2019 from Nanchang Customs that yellow fever virus was detected in a foreign national.On November 8,county,municipal,and provincial CDCs of Jiangxi Province carried out epidemiological investigations to show that the suspected case was found in a 35-year-old male patient from Addis Ababa,Ethiopia.On November 5,this patient began to have yellow-fever-like symptoms such as onset of fever,chills,and headache.