The photo-decomposition and self-restructuring dynamic equilibrium mechanism of Cu_(2)(OH)_(2)CO_(3)for stable photocatalytic CO_(2)reduction

Developing suitable photocatalysts and understanding their intrinsic catalytic mechanism remain key challenges in the pursuit of highly active,good selective,and long-term stable photocatalytic CO_(2)reduction(PCO_(2)R)systems.Herein,monoclinic Cu_(2)(OH)_(2)CO_(3)is firstly proven to be a new class of photocatalyst,which has excellent catalytic stability and selectivity for PCO_(2)R in the absence of any sacrificial agent and cocatalysts.Based on a Cu_(2)(OH)_(2)^(13)CO_(3)photocatalyst and 13CO_(2)two-sided^(13)C isotopic tracer strategy,and combined with in situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)analysis and density functional theory(DFT)calculations,two main CO_(2)transformation routes,and the photo-decomposition and self-restructuring dynamic equilibrium mechanism of Cu_(2)(OH)_(2)CO_(3)are definitely revealed.The PCO_(2)R activity of Cu_(2)(OH)_(2)CO_(3)is comparable to some of state-of-the-art novel photocatalysts.Significantly,the PCO_(2)R properties can be further greatly enhanced by simply combining Cu_(2)(OH)_(2)CO_(3)with typical TiO_(2)to construct composites photocatalyst.The highest CO_(2)and CH_(4)production rates by 7.5 wt%Cu_(2)(OH)_(2)CO_(3)-TiO_(2)reach 16.4μmol g^(-1)h^(-1)and 116.0μmol g^(-1)h^(-1),respectively,which are even higher than that of some of PCO_(2)R systems containing sacrificial agents or precious metals modified photocatalysts.This work provides a better understanding for the PCO_(2)R mechanism at the atomic levels,and also indicates that basic carbonate photocatalysts have broad application potential in the future.

应对可转移多黏菌素耐药性--饲料添加剂来源的白屈菜红碱具有双重效应

The emergence and spread of the mobile colistin-resistance gene,mcr-1,and its variants pose achallenge to the use of colistin,a last-resort antibiotic used to treat severe infections caused by extensively drug-resistant(XDR)Gram-negative pathogens.Antibiotic adjuvants are a promising strategy to enhance the efficacy of colistin against colistin-resistant pathogens;however,few studies have considered the effects of adjuvants on limiting resistance-gene transmission.We found that chelerythrine(4 mg·L^(-1))derived from Macleaya cordata extract,which is used as an animal feed additive,reduced the minimal inhibitory concentration(MIC)of colistin against an mcr-1 positive Escherichia coli(E.coli)strain by 16-fold(from 2.000 to 0.125 mg·L^(-1)).eliminated approximately 10^(4) colony-forming units(CFUs)of an mcr-1-carrying strain in a murine intestinal infection model,and inhibited the conjugation of an mcr-1-bearing plasmid in vitro(by>100-fold)and in a mouse model(by up to 5-fold).A detailed analysis revealed that chelery-thrine binds to phospholipids on bacterial membranes and increases cytoplasmic membrane fluidity,thereby impairing respiration,disrupting proton motive force(PMF),generating reactive oxygen species(ROS),and decreasing intracellular adenosine triphosphate(ATP)levels,which subsequently downregu-lates mcr-1 and conjugation-associated genes.These dual effects of chelerythrine can expand the use of antibiotic adjuvants and may provide a new strategy for circumventing mobile colistin resistance.

围产期护理缺失量表的汉化及信效度检验

目的翻译围产期护理缺失量表,并对其进行信度和效度检验,为国内开展围产期护理缺失的量性研究提供可靠的测评工具。方法采用美国矫形外科医师学会循证医学委员会推荐的跨文化调试量表指南对英文版围产期护理缺失量表进行翻译、回译-文化调适及内容验证,形成中文版围产期护理缺失量表,并通过横断面研究验证其信效度。于2023年2月至4月采用便利抽样法,选取西南地区14所不同级别医院491名助产士进行问卷调查。采用项目分析检验中文版量表条目的鉴别度,采用探索性和验证性因子分析评价量表的结构效度,采用内容效度指数和Cronbach'sa系数评价内容效度和信度。结果围产期护理缺失.量表包括A、B两部分。中文版围产期护理缺失量表A部分的项目-总量表相关系数为0.641 -0.866, B部分为0.644~0.819(P<0.01)。A部分和B部分的量表水平内容效度指数均为0.95,条目水平内容效度指数为0.86~1.00。探索性因子分析分别提取了A部分(必要性护理、基本护理和产后护理)和B部分(沟通、人力资源和物质资源)各3个因子,占总方差的70.186%和71.984%。量表A、B部分的Cronbach's a系数分别为0.968、0.940。结论中文版围产期护理缺失量表具有良好的信度和效度,可作为国内评价围产期护理缺失情况和相关原因的工具。未来需要进行更大样本量的研究,以验证该工具在中国本土的适用性。

FeCo alloy@N-doped graphitized carbon as an efficient cocatalyst for enhanced photocatalytic H2 evolution by inducing accelerated charge transfer

Cocatalysts play important roles in improving the activity and stability of most photocatalysts.It is of great significance to develop economical,efficient and stable cocatalysts.Herein,using Na2CoFe(CN)6 complex as precursor,a novel noble-metal-free FeCo@NGC cocatalyst(nano-FeCo alloy@N-doped graphitized carbon) is fabricated by a simple pyrolysis method.Coupling with g-C3 N4, the optimal FeCo@NGC/g-C3N4 receives a boosted visible light driven photocatalytic H2 evolution rate of 42.2 μmol h-1, which is even higher than that of 1.0 wt% Pt modified g-C3N4 photocatalyst.Based on the results of density functional theory(DFT) calculations and practical experiment measurements,such outstanding photocatalytic performance of FeCo@NGC/g-C3N4 is mainly attributed to two aspects.One is the accelerated charge transfer behavior,induced by a photogene rated electrons secondary transfer performance on the surface of FeCo alloy nanoparticles.The other is related to the adjustment of H adsorption energy(approaching the standard hydrogen electrode potential) by the presence of external NGC thin layer.Both factors play key roles in the H2 evolution reaction.Such outstanding performance highlights an enormous potential of developing noble-metal-free bimetallic nano-alloy as inexpensive and efficient cocatalysts for solar applications.

Studies of benzyl hydroxamic acid/calcium lignosulphonate addition order in the flotation separation of smithsonite from calcite

Flotation separation of smithsonite from calcite is difficult due to their similar surface properties.In the present study,a reagent scheme of depressant calcium lignosulphonate(CLS) and collector benzyl hydroxamic acid(BHA) was introduced in the flotation of smithsonite from calcite.Microflotation tests revealed that the efficient flotation of smithsonite from calcite could only be obtained with the addition order of BHA before CLS,which was opposite to the widely-used order that adding depressant prior to the collector.The zeta potential measurements indicated that BHA selectively adsorbed onto smithsonite surface,then not allowed the CLS adsorption onto the smithsonite surface rather than calcite surface because of the steric hindrance,thereby the smithsonite surface remained hydrophobic while calcite surface became more hydrophilic after the addition of CLS.As a result,the calcite flotation was completely depressed while the smithsonite flotation recovery was still in high value,leading to the optimal flotation separation performance.

Exploration of amino trimethylene phosphonic acid to eliminate the adverse effect of seawater in molybdenite flotation

In this investigation,a chelating agent of amino trimethylene phosphonic acid(ATMP) was introduced to eliminate the adverse effect of seawater in molybdenite flotation.Microflotation results presented that high flotation recovery of molybdenite was achieved in freshwater using kerosene as the collector,but it was significantly decreased in the presence of seawater when pH> 9.5.Among the main ions in seawater,magnesium and calcium ions played a more detrimental role than others.After the addition of ATMP,molybdenite floatability can restore in seawater.Zeta potential distribution and solution chemistry calculation results illustrated that the decreased molybdenite floatability was attributed to the interaction of positive Mg(OH)_(2)(s)(major) and CaOH^(+)(minor) components with the molybdenite surface.The magnesium/calcium ions of positive components of Mg(OH)_(2)(s) and CaOH^(+) interacted with the ionized species of ATMP and then produced ATMP-calcium/magnesium complex,leading to the electrostatic repulsion between molybdenite and ATMP-calcium/magnesium complex that was restoring the molybdenite flotation.Hence,the ATMP can be utilized as an appropriate reagent to improve molybdenite flotation in seawater.

Carbon nanotube@silicon carbide coaxial heterojunction nanotubes as metal-free photocatalysts for enhanced hydrogen evolution

Considerable research efforts have been devoted to developing novel photocatalysts with increased performances by hybridizing inorganic nanomaterials with carbon nanotubes.In this work,one-dimensional coaxial core-shell carbon nanotubes@SiC nanotubes were successfully synthesized via in situ growth of SiC coatings on carbon nanotubes by a vapor-solid reaction between silicon vapor and carbon nanotubes.High-resolution transmission electron microscope images show that SiC and carbon nanotubes link to form a robust heterojunction with intrinsic atomic contact,which results in efficient separation of the photogenerated electron-hole pairs on SiC and electron transfer from SiC to carbon nanotubes.Compared with those of similar materials such as pure SiC nanocrystals and SiC nanotubes,the metal-free carbon nanotubes@SiC exhibits an enhanced photocatalytic activity for hydrogen evolution,which is attributed to the enhanced light absorption and the efficient interfacial charge transfer/separation brought about by their one-dimensional coaxial nanoheterostructures.Moreover,the photocatalytic stability of the metal-free carbon nanotubes@SiC was tested for over 20 h without any obvious decay.

“翻转课堂”教学法在无机及分析化学课程教学中的实践与效果分析

翻转课堂倡导主动学习,这种线上线下混合式的学习方法广受学生欢迎。翻转课堂主要包括两个部分:第一,学生远离课堂的线上自主学习;第二,互动的、以课堂为基础的鼓励解决问题和体验式的学习活动。以翻转课堂教学法和传统教学法对生物类专业本科一年级学生开展无机及分析化学课程的教学,采用统计分析软件SPSS分析学生的成绩表现和对翻转课堂教学法的满意度。分析结果表明,学生积极参与翻转课堂教学环节,整体成绩得到明显提高,学生对翻转课堂教学法的满意度较高,说明翻转课堂教学法比传统教学法优势明显。

Research on the Effects of the Extract of Polygala fallax Hemsl on Sex Hormones andβ-EP in Perimenopausal Rat Models

Objective:To study the effects of the ethnic medicine Polygala fallax Hemsl with Guangxi characteristics on the sex hormones andβ-EP in research objective perimenopausal rat models.Methods:40 female SPF rats were randomly divided into 4 groups,including the normal,model,high-dose and lowdose groups.Rats of three groups except for the normal one were treated with perimenopausal modelling through the method of subcutaneous injection of compound 4-VCD for 15 consecutive days.Rats of the normal and model group were normally fed without any treatment.Rats of the high-dose and low-dose groups were administered by high-and low-dose intragastric administration of the extract of Polygala fallax Hemsl.According to the menstrual cycle of the vaginal smear of the rat,each menstrual cycle is a course of treatment and 6 consecutive courses of treatment would be given.The indexes of serum sex hormones(E2,FSH,LH)andβ-EP of rats in each group were observed after treatment.Results:After the treatment of 6 cycles,for the levels ofβ-EP and E2,the model group was lowest(P<0.05),the normal group was highest(P<0.05);and the high-dose group was higher than the low-dose group;For the levels of FSH and LH,the normal group was lowest(P<0.05),the model group was highest(P<0.05),and the high-dose group was lower than the low-dose group.Conclusion:Guangxi characteristic national medicine Polygala fallax Hemsl can effectively improve the levels of serum sex hormones andβ-EP in perimenopausal rat models and relieve the related symptoms with a certain dose-effect relationship.

Photoinduced Cu^(+)/Cu^(2+)interconversion for enhancing energy conversion and storage performances of CuO based Li-ion battery

Pursuing appropriate photo-active Li-ion storage materials and understanding their basic energy storage/conversion principle are pretty crucial for the rapidly developing photoassisted Li-ion batteries(PA-LIBs).Copper oxide(CuO)is one of the most popular candidates in both LIBs and photocatalysis.While CuO based PA-LIBs have never been reported yet.Herein,one-dimensional(1D)CuO nanowire arrays in situ grown on a three-dimensional(3D)copper foam support were employed as dualfunctional photoanode for both‘solar-to-electricity’and‘electricity-to-chemical’energy conversion in the PA-LIBs.It is found that light energy can be indeed stored and converted into electrical energy through the assembled CuO based PA-LIBs.Without external power source,the photo conversion efficiency of CuO based photocell reaches about 0.34%.Impressively,at a high current density of 4000 m A g^(-1),photoassisted discharge and charge specific capacity of CuO based PA-LIBs respectively receive 64.01%and 60.35%enhancement compared with the net electric charging and discharging process.Mechanism investigation reveals that photogenerated charges from CuO promote the interconversion between Cu^(2+)and Cu^(+)during the discharging/charging process,thus forcing the lithium storage reaction more completely and increasing the specific capacity of the PA-LIBs.This work can provide a general principle for the development of other high-efficient semiconductor-based PA-LIBs.

Analysis on diffusion-induced stress for multi-layer spherical core-shell electrodes in Li-ion batteries

Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes.Herein,a multilayer spherical core-shell(M-SCS)electrode with a graphite framework prepared with Si@O-MCMB/C nanoparticles is developed,which aims to realize chemically/mechanically stability during the lithiation/delithiation process with high specific capacity.An electrochemical-/mechanical-coupling model for the M-SCS structure is established with various chemical/mechanical boundary conditions.The simulation of finite difference method(FDM)has been conducted based on the proposed coupling model,by which the diffusion-induced stress along both the radial and the circumferential directions is determined.Moreover,factors that influence the diffusion-induced stress of the M-SCS structure have been discussed and analyzed in detail.

PCAF-mediated acetylation of METTL3 impairs mRNA translation efficiency in response to oxidative stress

METTL3 methylates RNA and regulates the fate of mRNA through its methyltransferase activity.METTL3 enhances RNA translation independently of its catalytic activity.However,the underlying mechanism is still elusive.Here,we report that METTL3 is both interacted with and acetylated at lysine 177 by the acetyltransferase PCAF and deacetylated by SIRT3.Neither the methyltransferase activity nor the stability of METTL3 is affected by its acetylation at K177.Importantly,acetylation of METTL3 blocks its interaction with EIF3H,a subunit of the translation initiation factor,thereby reducing mRNA translation efficiency.Interestingly,acetylation of METTL3 responds to oxidative stress.Mechanistically,oxidative stress enhances the interaction of PCAF with METTL3,increases METTL3 acetylation,and suppresses the interaction of METTL3 with EIF3H,thereby decreasing the translation efficiency of ribosomes and inhibiting cell proliferation.Altogether,we suggest a mechanism by which oxidative stress regulates RNA translation efficiency by the modulation of METTL3 acetylation mediated by PCAF.

Geometric edge effect on the interface of Au/CeO_(2)nanocatalysts for CO oxidation

The oxide supports play a crucial role in anchoring and promoting the active metal species by geometric confinement and chemical interaction.The design and synthesis of the well-defined oxide support with specific morphology such as size,shape,and exposed facets have attracted extensive research efforts,which directly reflects on their catalytic performance.In this study,using an Au/CeO_(2)-nanorod model catalyst,we demonstrate an edge effect on the Au/CeO_(2)interfacial structure,which shows a prominent effect on the structure-performance relationship in the CO oxidation reaction.This specific“edge-interface”structure features an“edge-on”Au nanoparticles position on rod-shaped CeO_(2)support,confirmed by atomic-scale electron microscopy characterization,which introduces additional degrees of freedom in coordination environment,chemical state,bond length,and strength.Combined with theocratical calculations and in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)investigations,we confirmed that this“edge-interface”has distinct adsorption properties due to the change of O vacancy formation energy as well as the chemical states of Au resulting from the electron transfer and redistribution between the metal and the support.These results demonstrate a non-conventional geometric effect of rod-shaped supported metal catalysts on the catalytic performance,which could provide insights into the atomic-precise utilization of catalysts.

Multiscale modeling of mechanical behavior and failure mechanism of 3D angle-interlock woven aluminum composites subjected to warp/weft directional tension loading

The mechanical behavior and progressive damage mechanism of novel aluminum matrix composites reinforced with 3D angle-interlock woven carbon fibers were investigated using a multiscale modeling approach.The mechanical properties and failure of yarns were evaluated using a microscale model under different loading scenarios.On this basis,a mesoscale model was developed to analyze the tensile behavior and failure mechanism of the composites.The interfacial decohesion,matrix damage,and failure of fibers and yarns were incorporated into the microscopic and mesoscopic models.The stress–strain curves and fracture modes from simulation show good agreement with the experimental curves and fracture morphology.Local interface and matrix damage initiate first under warp directional tension.Thereafter,interfacial failure,weft yarn cracking,and matrix failure occur successively.Axial fracture of warp yarn,which displays a quasi-ductile fracture characteristic,dominates the ultimate composites failure.Under weft directional tension,interfacial failure and warp yarn rupture occur at the early and middle stages.Matrix failure and weft yarn fracture emerge simultaneously at the final stage,leading to the cata-strophic failure of composites.The weft directional strength and fracture strain are lower than the warp directional ones because of the lower weft density and the more serious brittle fracture of weft yarns.

LATS1 K751 acetylation blocks activation of Hippo signalling and switches LATS1 from a tumor suppressor to an oncoprotein

Large tumor suppressor 1(LATS1)is the key kinase controlling activation of Hippo signalling pathway.Post-translational modifications of LATS1 modulate its kinase activity.However,detailed mechanism underlying LATS1 stability and activation remains elusive.Here we report that LATS1 is acetylated by acetyltransferase CBP at K751 and is deacetylated by deacetylases SIRT3 and SIRT4.Acetylation at K751 stabilized LATS1 by decreasing LATS1 ubiquitination and inhibited LATS1 activation by reducing its phosphorylation.Mechanistically,LATS1 acetylation resulted in inhibition of YAP phosphorylation and degradation,leading to increased YAP nucleus translocation and promoted target gene expression.Functionally,LATS1-K751 Q,the acetylation mimic mutant potentiated lung cancer cell migration,invasion and tumor growth,whereas LATS1-K751 R,the acetylation deficient mutant inhibited these functions.Taken together,we demonstrated a previously unidentified post-translational modification of LATS1 that converts LATS1 from a tumor suppressor to a tumor promoter by suppression of Hippo signalling through acetylation of LATS1.

Rapid and accurate identification of SARS-CoV-2 variants containing E484 mutation

The ongoing coronavirus disease 2019(COVID-19)pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection has led to over 240 million confirmed infections and severe economic burdens worldwide.Multiple emerging SARS-CoV-2 variants of concern(VOCs)and variants of interest(VOIs)have recently beenidentifiedand are nowspreading internationally,including B.1.1.7(Alpha),B.1.351(Beta),P.1(Gamma),B.1.617(Delta and Kappa),C.37(Lambda),and B.1.621(Mu),all of which appear to bemore easily transmitted(WHO,COVID-19Weekly EpidemiologicalUpdate).Beta andGamma VOCs can seriously impair the protective efficacy of existing vaccines,potentially precluding the possibility of attaining"herd immunity."

Factors Associated with SARS-CoV-2 Repeat Positivity—Beijing,China,June–September 2020

Introduction:Repeat positive severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)following COVID-19 initial viral clearance(repositivity)poses a public health management challenge.The objective was to determine factors associated with neutralizing antibody(Nab)level and re-positivity among patients infected with a single strain SARS-CoV-2.Methods:During a single strain SARS-CoV-2 cluster in Beijing,China,longitudinal individual clinical,virological,and immunological data were collected from 368 infections from June 13 to September 22,2020.Factors associated with Nab level and re-positivity were analyzed using generalized estimating equations.Results:A total of 353(96%)SARS-CoV-2 infections had demographic,clinical,and laboratory data available.Among the 353 infections,55(15.5%)were re-positive,and blood draws were taken from 346 individuals(98.0%)during hospitalization and/or during the follow-up period.Symptoms were milder for the second-time admission for the re-positives,although 36.4%of re-positives presented with radiographic appearance of pneumonia manifestation.Compared to non-re-positive patients,NAb titers were lower among re-positives;NAb was positively associated with clinical severity.Samples from the lower respiratory tract manifested higher viral load than that from the upper respiratory tract.Multivariable analysis showed re-positivity was positively associated with being female[odd ratio(OR)=1.7,95%confidence interval(CI)1.1–2.8]and being aged<18 years(OR=5.2,95%CI 1.5–18.1);having initially asymptomatic infection(OR=13.7,95%CI 1.6–116.3);and negatively associated with a higher NAb level(OR=0.9,95%CI 0.5–1.7).Conclusions:NAb may be important for sustained viral clearance.Lower respiratory tract infection was associated with higher viral load among all infections when compared to upper respiratory tract infection.Continuous lower respiratory and intermittent upper respiratory viral shedding among COVID-19 infections may occur.

Microstructural,crystallographic,and mechanical characteristics in Ni-Mn-Ga alloys directionally solidified under a transverse magnetic field

In this study,the effect of transverse magnetic field-assisted directional solidification(MFADS)on the microstructures in Ni-Mn-Ga alloys has been investigated.The results show that the magnetic field is capable of inducing transversal macrosegregation perpendicular to the magnetic field,causing the emergence of martensite clusters in the austenite matrix.Moreover,the magnetic field alleviates the microseg-regation on a dendritic scale and promotes the preferred growth of austenite dendrites.On the basis of the above investigation,several special samples are designed using the MFADS to study the crystallographic evolution and mechanical behavior during thermal/stress-induced martensite transformation.The martensite cluster in the austenite matrix is used to investigate the martensite transformation and growth under cooling-heating cycles.The crystallographic relationship and phase boundary microstructure between martensite and austenite have been characterized.In addition,the microsegregation on a dendritic scale can significantly influence the martensite variant distribution,corresponding to the performance during compressive circles based on the analysis of the deformation gradient tensor.The stress-induced superelasticity is closely dependent on orientation,well explained from the perspective of different resolved shear stress factors and correspondence variant pair formation transformation strain.The crystallographic evolution has been characterized during in-situ stress-induced transformation.The findings not only deepen the understanding of martensite transformation and mechanical behavior under a thermal/stress field in Ni-Mn-Ga alloys but also propose a promising strategy to obtain microstructure-controllable functional alloys by MFADS.

Microstructure evolution and mechanical behavior of Ni-rich Ni-Mn-Ga alloys under compressive and tensile stresses

The microstructure evolution and mechanical behavior in directionally solidified Ni-rich Ni-Mn-Ga alloys with nominal compositions of Ni_(58)Mn_(25)Ga_(17) and Ni_(60)Mn_(25)Ga_(15) under compressive and tensile stresses have been investigated.The composition distribution shows the element Ni segregates in gamma phase,while elements Mn and Ga segregate in martensite phase.Furthermore,the microstructure orientation examined by electron backscatter diffraction(EBSD)indicates that beta phase has a preferred growth orientation of(001)_(A) in Ni_(58)Mn_(25)Ga_(17) alloys,while gamma phase has a preferred growth orientation of(001)_(γ) in Ni_(60)Mn_(25)Ga_(15) alloys.The fracture morphology suggests that the existence of ductile y phase can reduce the crack propagation and promote fracture strain,particularly in the Ni_(60)Mn_(25)Ga_(15) alloys.Finally,Schmid factor and deformation gradient tensor were calculated to well explain the crystallographic evolution during the detwinning under compressive and tensile stresses.The present findings not only elucidate the mechanism ofγphase on the mechanical behavior of Ni-rich Ni-Mn-Ga alloys,but also shed light on the composition design of high temperature Ni-Mn-Ga shape memory alloys.

Vital Surveillances: Factors Associated with SARS-CoV-2 Repeat Positivity-Beijing, China, June-September 2020

全球各地陆续出现新冠患者康复后再次核酸阳性的情况,引发了行业内的关注。先前有关复阳的研究均来自于不同的传播链,感染者感染的毒株不尽相同。为减少不同毒株而引发的复阳的选择偏倚,有必要对感染同一毒株的新冠患者的复阳情况进行研究。中和抗体水平被认为在清除新冠病毒中发挥重要作用,被用于治疗新冠患者。本研究纳入人口学、临床、实验室数据及重复测量中和抗体和病毒载量,分析了影响新冠患者复阳的因素。结果显示,353个病例中,约15%患者康复后复阳,这一结果与大部分有关复阳的研究结果相符。使用多因素广义估计模型对复阳进行分析发现,复阳和患者中和抗体水平成负相关,即抗体水平低,复阳的可能性更大。提示可能因抗体水平低,不足以完全清除病毒而导致复阳。