Saccades of video head impulse test in Meniere's disease and Vestibular Migraine: What can we learn from?

Background:Saccades are often observed on video head impulse tests(vHIT)in patients with Meniere's Disease(MD)and Vestibular Migraine(VM).However,their saccadic features are not fully described.Objective:This study aims to identify the saccades characteristics of MD and VM.Methods:75 VM patients and 103 definite unilateral MD patients were enrolled in this study.First raw saccades were exported and analyzed.The VM patients were divided into left and right based on their ears,while the MD patients were separated into affected and unaffected subgroups based on their audiograms and symptoms.Results:The MD patients have more saccades on the affected side(85%vs.69%),and saccade velocity is more consistent than the contralateral side(shown by the coefficient of variation).The saccades occurrence rates on both sides are similar in VM(77%vs.76%),as are other saccadic parameters.The MD patients have more significant inter-aural differences than the VM patients,manifested in higher velocity(p-value 0.000),earlier arriving(p-value 0.010),and more time-domain gathered(p-value 0.003)on the affected side.Conclusions:Bilateral saccades are commonly observed in MD and VM.In contrast to MD,saccades on VM are subtle,scattered,and late-arrived.Furthermore,the MD patients showed inconsistent saccadic distribution with more velocity-uniform saccades on the affected side.

Early detection of pine wilt disease in Pinus tabuliformis in North China using a field portable spectrometer and UAV-based hyperspectral imagery

Background:Pine wilt disease(PWD)is a major ecological concern in China that has caused severe damage to millions of Chinese pines(Pinus tabulaeformis).To control the spread of PWD,it is necessary to develop an effective approach to detect its presence in the early stage of infection.One potential solution is the use of Unmanned Airborne Vehicle(UAV)based hyperspectral images(HIs).UAV-based HIs have high spatial and spectral resolution and can gather data rapidly,potentially enabling the effective monitoring of large forests.Despite this,few studies examine the feasibility of HI data use in assessing the stage and severity of PWD infection in Chinese pine.Method:To fill this gap,we used a Random Forest(RF)algorithm to estimate the stage of PWD infection of trees sampled using UAV-based HI data and ground-based data(data directly collected from trees in the field).We compared relative accuracy of each of these data collection methods.We built our RF model using vegetation indices(VIs),red edge parameters(REPs),moisture indices(MIs),and their combination.Results:We report several key results.For ground data,the model that combined all parameters(OA:80.17%,Kappa:0.73)performed better than VIs(OA:75.21%,Kappa:0.66),REPs(OA:79.34%,Kappa:0.67),and MIs(OA:74.38%,Kappa:0.65)in predicting the PWD stage of individual pine tree infection.REPs had the highest accuracy(OA:80.33%,Kappa:0.58)in distinguishing trees at the early stage of PWD from healthy trees.UAV-based HI data yielded similar results:the model combined VIs,REPs and MIs(OA:74.38%,Kappa:0.66)exhibited the highest accuracy in estimating the PWD stage of sampled trees,and REPs performed best in distinguishing healthy trees from trees at early stage of PWD(OA:71.67%,Kappa:0.40).Conclusion:Overall,our results confirm the validity of using HI data to identify pine trees infected with PWD in its early stage,although its accuracy must be improved before widespread use is practical.We also show UAV-based data PWD classifications are less accurate but comparable to those of ground-based data.We believe that these results can be used to improve preventative measures in the control of PWD.

Combining WV-2 images and tree physiological factors to detect damage stages of Populus gansuensis by Asian longhorned beetle (Anoplophora glabripennis) at the tree level

Background:Anoplophora glabripennis(Motschulsky),commonly known as Asian longhorned beetle(ALB),is a wood-boring insect that can cause lethal infestation to multiple borer leaf trees.In Gansu Province,northwest China,ALB has caused a large number of deaths of a local tree species Populus gansuensis.The damaged area belongs to Gobi desert where every single tree is artificially planted and is extremely difficult to cultivate.Therefore,the monitoring of the ALB infestation at the individual tree level in the landscape is necessary.Moreover,the determination of an abnormal phenotype that can be obtained directly from remote-sensing images to predict the damage degree can greatly reduce the cost of field investigation and management.Methods:Multispectral WorldView-2(WV-2)images and 5 tree physiological factors were collected as experimental materials.One-way ANOVA of the tree’s physiological factors helped in determining the phenotype to predict damage degrees.The original bands of WV-2 and derived vegetation indices were used as reference data to construct the dataset of a prediction model.Variance inflation factor and stepwise regression analyses were used to eliminate collinearity and redundancy.Finally,three machine learning algorithms,i.e.,Random Forest(RF),Support Vector Machine(SVM),Classification And Regression Tree(CART),were applied and compared to find the best classifier for predicting the damage stage of individual P.gansuensis.Results:The confusion matrix of RF achieved the highest overall classification accuracy(86.2%)and the highest Kappa index value(0.804),indicating the potential of using WV-2 imaging to accurately detect damage stages of individual trees.In addition,the canopy color was found to be positively correlated with P.gansuensis’damage stages.Conclusions:A novel method was developed by combining WV-2 and tree physiological index for semi-automatic classification of three damage stages of P.gansuensis infested with ALB.The canopy color was determined as an abnormal phenotype that could be directly assessed using remote-sensing images at the tree level to predict the damage degree.These tools are highly applicable for driving quick and effective measures to reduce damage to pure poplar forests in Gansu Province,China.

Analysis of video head impulse test saccades data in patients with vestibular migraine or probable vestibular migraine

Objective:Saccades accompanied by normal gain in video head impulse tests(vHIT)are often observed in patients with vestibular migraine(VM).However,they are not considered as an independent indicator,reducing their utility in diagnosing VM.To better understand clinical features of VM,it is necessary to understand raw saccades data.Methods:Fourteen patients with confirmed VM,45 patients with probable VM(p-VM)and 14 agematched healthy volunteers were included in this study.Clinical findings related to spontaneous nystagmus(SN),positional nystagmus(PN),head-shaking nystagmus(HSN),caloric test and vHIT were recorded.Raw saccades data were exported and numbered by their sequences,and their features analyzed.Results:VM patients showed no SN,PN or HSN,and less than half of them showed unilateral weakness(UW)on caloric test.The first saccades from lateral semicircular canal stimulation were the most predominant for both left and right sides.Neither velocity nor time parameters were significantly different when compared between the two sides.Most VM patients(86%)exhibited small saccades,around 35%of the head peak velocity,with a latency of 200e400 ms.Characteristics of saccades were similar in patients with p-VM.Only four normal subjects showed saccades,all unilateral and seemingly random.Conclusions:Small saccades involving bilateral semicircular canals with a scattered distribution pattern are common in patients with VM and p-VM.

A new approach to endocochlear potential and potassium ion concentration measures in mini pig models

Mini pig models are large mammals and their ears are more similar with human beings in structure and development than other animals.However,the study on porcine ears is still in the initial stage and there is no description of an ideal operation approach to endocochlear potential and potassium ion concentration measurements.In this article,we describe a pre-auricular surgical approach to access the middle and inner ear for endocochlear potential and potassium ion concentration measures in mini pig models.Ten one-week old normal mini pigs were used in the study.The bulla of the temporal bone was accessed via a pre-auricular approach for endocochlear potential and potassium ion concentration measurements.The condition of the animals during the first post—experiment 24 h was observed.One animal died during surgery.The preauricular approach improved protection and preservation of relevant nervous and vascular elements including the facial nerve and carotid artery.So,the pre-auricular approach can be used for endocochlear potential and potassium ion concentration measurements with improved nerve and artery preservation mini pigs.

Transcript variants and expression profiles analysis of Mitf gene in minipigs

Object： To identify transcript variants and expression patterns of porcine Mitf. Materials and methods： A pairwise BLAST search at NCBI database was performed to deduce the structure of porcine Mitf gene. Subsequently, 5＇ RACE and fluorescent quantitative RT-PCR were used to analyze the expression pattern of porcine Mitf in different tissues. Results： Four transcript variants of porcine Mitf, MITF-A, MITF-H, MITF-M and MITF-SUS were identified, all sharing high homology with those in humans, except Mitf-SUS.Conclusion： The sequence of porcine Mitf appear highly homologous to human MITF. However, only 4 transcript variants of porcine Mitf were identified in these minipigs, less than the 9 transcript variants in human MITF.

Screening and identifying natural products with SARS-CoV-2 infection inhibitory activity from medicinal fungi

The coronavirus disease of 2019(COVID‐19),a global pandemic caused by the severe acute respiratory syndrome coronavirus 2(SARS‐CoV‐2),can result in severe health complications.In addition to physical preventative measures,pharmaceutical intervention is also crucial.Numerous natural products from medicinal fungi have shown promise as potential antiviral drugs and may serve as a source of effective components with antiviral activity against SARS‐CoV‐2 and other coronaviruses.In this study,we developed a workflow that integrates viral infection inhibition assays at both cellular and molecular levels,as well as molecular separation and characterization,to screen and identify natural products with antiviral activity.Using this workflow,we screened 167 extracts extracted from 36 medicinal fungi using optimized extraction methods.We assessed the antiviral effects of these extracts by measuring their ability to inhibit SARS‐CoV‐2 infection and receptor binding domain‐human angiotensin‐converting enzyme 2(RBD‐hACE2)binding in vitro.Following charge‐and size‐based characterization of the active compounds through filtration and chromatographic fractionation,mass spectrometry characterization of the fractionated compounds revealed that the active components are polysaccharides and determined their monosaccharide residue composition.Our findings provide new insights into the antiviral potential of natural products and their screening strategies and may contribute to the development of effective antiviral therapeutics against COVID‐19 and other diseases.

Impact of corticosteroids on initiation and half-year durability of humoral response in COVID-19 survivors

Background:The impact of corticosteroids on humoral responses in coronavirus disease 2019(COVID-19)sur-vivors during the acute phase and subsequent 6-month period remains unknown.This study aimed to determine how the use of corticosteroids influences the initiation and duration of humoral responses in COVID-19 survivors 6 months after infection onset.Methods:We used kinetic antibody data from the lopinavir-ritonavir trial conducted at Jin Yin-Tan Hospital in January 2020,which involved adults hospitalized with severe COVID-19(LOTUS,ChiCTR2000029308).Anti-body samples were collected from 192 patients during hospitalization,and kinetic antibodies were monitored at all available time points after recruitment.Additionally,plasma samples were collected from 101 COVID-19 survivors for comprehensive humoral immune measurement at the half-year follow-up visit.The main focus was comparing the humoral responses between patients treated with systemic corticosteroid therapy and the non-corticosteroid group.Results:From illness onset to day 30,the median antibody titre areas under the receiver operating characteristic curve(AUCs)of nucleoprotein(N),spike protein(S),and receptor-binding domain(RBD)immunoglobulin G(IgG)were significantly lower in the corticosteroids group.The AUCs of N-,S-,and RBD-IgM as well as neutralizing antibodies(NAbs)were numerically lower in the corticosteroids group compared with the non-corticosteroid group.However,peak titres of N,S,RBD-IgM and-IgG and NAbs were not influenced by corticosteroids.During 6-month follow-up,we observed a delayed decline for most binding antibodies,except N-IgM(𝛽−0.05,95%CI[−0.10,0.00])in the corticosteroids group,though not reaching statistical significance.No significant difference was observed for NAbs.However,for the half-year seropositive rate,corticosteroids significantly accelerated the decay of IgA and IgM but made no difference to N-,S-,and RBD-IgG or NAbs.Additionally,corticosteroids group showed a trend towards delayed viral clearance compared with the non-corticosteroid group,but the results were not statistically significant(adjusted hazard ratio 0.71,95%CI 0.50-1.00;P=0.0508).Conclusion:Our findings suggested that corticosteroid therapy was associated with impaired initiation of the antibody response but this did not compromise the peak titres of binding and neutralizing antibodies.Throughout the decay phase,from the acute phase to the half-year follow-up visit,short-term and low-dose corticosteroids did not significantly affect humoral responses,except for accelerating the waning of short-lived antibodies.

Polymer types regulation strategy toward the synthesis of carbonized polymer dots with excitation-wavelength dependent or independent fluorescence

Three kinds of carbonized polymer dots(CPDs) synthesized via a one-pot process from ophenylenediamine(OPD), m-phenylenediamine(MPD) and p-phenylenediamine(PPD) exhibit excitationwavelength independent yellow, green and red emissions, respectively. In sharp contrast, two kinds of CPDs prepared via a hydrothermal process from citric acid(CA) and diethylenetriamine(DETA) exhibit obvious excitation-wavelength dependent emissions. Through the characterization and comparison of the two types of CPDs, it is concretely revealed that the polymer structure types during the formation of CPDs can effectively control the fluorescence excitation-wavelength independence/dependence. The homogeneous polymer structures contained in CPDs contribute to excitation-wavelength independence, whereas random copolymer structures contribute to excitation-wavelength dependence. These studies are of great significance for further understanding the polymer structures and designing unique optical properties of CPDs.

Serosurvey for SARS-CoV-2 among blood donors in Wuhan,China from September to December 2019

The emerging of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)caused COVID-19 pandemic.The first case of COVID-19 was reported at early December in 2019 in Wuhan City,China.To examine specific antibodies against SARS-CoV-2 in biological samples before December 2019 would give clues when the epidemic of SARS-CoV-2 might start to circulate in populations.We obtained all 88,517 plasmas from 76,844 blood donors in Wuhan between 1 September and 31 December 2019.We first evaluated the pan-immunoglobin(pan-Ig)against SARS-CoV-2 in 43,850 samples from 32,484 blood donors with suitable sample quality and enough volume.Two hundred and sixty-four samples from 213 donors were pan-Ig reactive,then further tested IgG and IgM,and validated by neutralizing antibodies against SARS-CoV-2.Two hundred and thirteen samples(from 175 donors)were only pan-Ig reactive,8(from 4 donors)were pan-Ig and IgG reactive,and 43(from 34 donors)were pan-Ig and IgM reactive.Microneutralization assay showed all negative results.In addition,213 screened reactive donors were analyzed and did not show obviously temporal or regional tendency,but the distribution of age showed a difference compared with all tested donors.Then we reviewed SARS-CoV-2 antibody results from these donors who donated several times from September 2019 to June 2020,partly tested in a previous published study,no one was found a significant increase in S/CO of antibodies against SARS-CoV-2.Our findings showed no SARS-CoV-2-specific antibodies existing among blood donors in Wuhan,China before 2020,indicating no evidence of transmission of COVID-19 before December 2019 in Wuhan,China.

Changes in the pathogen spectrum of hospitalized adults with community-acquired pneumonia in Fujian Province: A multicenter, retrospective study from 2012 to 2018

To the Editor:Community-acquired pneumonia(CAP)in adults refers to inflammation of the lung parenchyma involving the alveolar wall.It occurs in the community environment(outside the hospital),including pneumonia caused by pathogens with definite latency after admission.

Temporal dynamics of SARS-CoV-2 genome mutations that occurred in vivo on an aircraft

We analyzed variations in the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)genome during a flight-related cluster outbreak of coronavirus disease 2019(COVID-19)in Shenzhen,China,to explore the characteristics of SARS-CoV-2 transmission and intra-host single nucleotide variations(iSNVs)in a confined space.Thirty-three patients with COVID-19 were sampled,and 14 were resampled 3-31 days later.All 47 nasopharyngeal swabs were deep-sequenced.iSNVs and similarities in the consensus genome sequence were analyzed.Three SARS-CoV-2 variants of concern,Delta(n=31),Beta(n=1),and C.1.2(n=1),were detected among the 33 patients.The viral genome sequences from 30 Delta-positive patients had similar SNVs;14 of these patients provided two successive samples.Overall,the 47 sequenced genomes contained 164 iSNVs.Of the 14 paired(successive)samples,the second samples(T2)contained more iSNVs(median:3;95%confidence interval[95%CI]:2.77-10.22)than did the first samples(T1;median:2;95%CI:1.63-3.74;Wilcoxon test,P=0.021).38 iSNVs were detected in T1 samples,and only seven were also detectable in T2 samples.Notably,T2 samples from two of the 14 paired samples had additional mutations than the T1 samples.The iSNVs of the SARS-CoV-2 genome exhibited rapid dynamic changes during a flight-related cluster outbreak event.Intra-host diversity increased gradually with time,and new site mutations occurred in vivo without a population transmission bottleneck.Therefore,we could not determine the generational relationship from the mutation site changes alone.

供应商集中度与企业存货效率

管理作为企业运营管理的重要方面,彩响企业价值的创造。本文从供应链视角出发,利用我国A股上市公司2001—2016年的数据,探讨供应商集中度对企业存货效率的影响。研究发现,供应商集中度与原材料收入比呈显著负相关关系,与原材料周转率呈显著正相关关系,即供应商集中度越高.企业持有存货数量越少,持有存货时间越短,供应商集中会大大提升企业的存货效率。进一步研究表明,关系专有投资越多,企业议价能力越强,供应商集中度对企业存货效率的提升作用越强;但当供应商来自国外时,会对供应商集中度对企业存货效率的提升产生抑制作用。这种情况在处理内生性问题及进行一系列的稳健性检验后,结果依旧显著。本文从外部利益相关者——供应商的视角出发,研究其与存货效率的关系,找到了企业价值创造的新路径,丰富了供应商对企业财务行为彩响的相关文献,也为企业的供应商选择及存货管理提供了相应的借鉴。

管理者过度自信与企业牛鞭效应

本文从管理会计的视角出发,利用沪深两市A股上市公司2007—2017年的数据,研究管理者过度自信对企业牛鞭效应的影响。研究发现:管理者过度自信会加剧企业的牛鞭效应。本文利用中介效应模型,进一步探讨管理者过度自信是否会通过供应商选择路径和存货管理路径影响企业牛鞭效应。管理者过度自信程度越高.企业供应商集中度越高,存货持有量越多,存货周转越慢,企业牛鞭效应越显著。此外,管理者过度自信对牛鞭效应的影响在国有企业中更加显著.而良好的内部控制和分析师跟踪可以减弱管理者过度自信对牛鞭效应的影响。本文丰富了管理者过度自信经济后果的研究,也为牛鞭效应的影响因素提供了行为财务方面的解释。

Construction of Non-infectious SARS-CoV-2 Replicons and Their Application in Drug Evaluation

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has caused a devastating pandemic worldwide.Vaccines and antiviral drugs are the most promising candidates for combating this global epidemic,and scientists all over the world have made great efforts to this end.However,manipulation of the SARS-CoV-2 should be performed in the biosafety level3 laboratory.This makes experiments complicated and time-consuming.Therefore,a safer system for working with this virus is urgently needed.Here,we report the construction of plasmid-based,non-infectious SARS-CoV-2 replicons with turbo-green fluorescent protein and/or firefly luciferase reporters by reverse genetics using transformation-associated recombination cloning in Saccharomyces cerevisiae.Replication of these replicons was achieved simply by direct transfection of cells with the replicon plasmids as evident by the expression of reporter genes.Using SARS-CoV-2 replicons,the inhibitory effects of E64-D and remdesivir on SARS-CoV-2 replication were confirmed,and the halfmaximal effective concentration(EC50)value of remdesivir and E64-D was estimated by different quantification methods respectively,indicating that these SARS-CoV-2 replicons are useful tools for antiviral drug evaluation.

Corilagin inhibits SARS-CoV-2 replication by targeting viral RNA-dependent RNA polymerase

Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2) has become one major threat to human population health.The RNA-dependent RNA polymerase(RdRp) presents an ideal target of antivirals,whereas nucleoside analogs inhibitor is hindered by the proofreading activity of coronavirus.Herein,we report that corilagin(RAI-S-37) as a non-nucleoside inhibitor of SARS-CoV-2 RdRp,binds directly to RdRp,effectively inhibits the polymerase activity in both cell-free and cell-based assays,fully resists the proofreading activity and potently inhibits SARS-CoV-2 infection with a low 50% effective concentration(EC50) value of 0.13 μmol/L.Computation modeling predicts that RAI-S-37 lands at the palm domain of RdRp and prevents conformational changes required for nucleotide incorporation by RdRp.In addition,combination of RAI-S-37 with remdesivir exhibits additive activity against antiSARS-CoV-2 RdRp.Together with the current data available on the safety and pharmacokinetics of corilagin as a medicinal herbal agent,these results demonstrate the potential of being developed into one of the much-needed SARS-CoV-2 therapeutics.

SARS-CoV-2 nsp12 attenuates type Ⅰ interferon production by inhibiting IRF3 nuclear translocation

SARS-CoV-2 is the pathogenic agent of COVID-19,which has evolved into a global pandemic.Compared with some other respiratory RNA viruses,SARS-CoV-2 is a poor inducer of type Ⅰ interferon(IFN).Here,we report that SARS-CoV-2 nsp12,the viral RNA-dependent RNA polymerase(RdRp),suppresses host antiviral responses.SARS-CoV-2 nsp12 attenuated Sendai virus(SeV)-or poly(I:C)-induced IFN-β promoter activation in a dose-dependent manner.It also inhibited IFN promoter activation triggered by RIG-I,MDA5,MAVS,and IRF3 overexpression.Nsp12 did not impair IRF3 phosphorylation but suppressed the nuclear translocation of IRF3.Mutational analyses suggested that this suppression was not dependent on the polymerase activity of nsp12.Given these findings,our study reveals that SARS-CoV-2 RdRp can antagonize host antiviral innate immunity and thus provides insights into viral pathogenesis.

Biomimetic Hydrophobic Surfaces with Low or High Adhesion Based on Poly（vinyl alcohol） and SiO2 Nanoparticles

Superhydrophobic surfaces are often found in nature, such as plant leaves and insect wings. Inspired by superhydrophobic phenomenon of the rose petals and the lotus leaves, biomimetic hydrophnbic surfaces with high or low adhesion were prepared with a facile drop-coating approach in this paper. Poly（vinyl alcohol） （PVA） was used as adhesive and SiO2 nanoparticles were used to fabricate surface micro-structure. Stearic acid or dodecafluoroheptyl-propyl-trimethoxysilane （DFTMS） were used as low surface energy materials to modify the prepared PVA/SiO2 coating surfaces. The effects of size of SiO2 nanoparticles, concentration of SiO2 nanoparticle suspensions and the modifications on the wettability of the surface were investigated. The morphology of the PVA/SiO2 coating surfaces was observed by using scanning electron microscope. Water contact angle of the obtained superhydrophilic surface could reach to 3°. Stearic acid modified PVA/SiO2 coating surfaces showed hydrophobicity with high adhesion. By mixing the SiO2 nanoparticles with sizes of 40 nm and 200 nm and modifying with DFTMS, water contact angle of the obtained coating surface could be up to 155° and slide angle was only 5°. This work provides a facile and useful method to control surface wettability through changing the roughness and chemical composition of a surface.

Sirolimus combined with oseltamivir and corticosteroid treatment for a puerpera with severe pneumonia caused by 2009 pandemic H1N1:A case report

Severe pneumonia in patients infected with the 2009 pandemic H1N1(pH1N1)virus was partially attributed to excessive immune response.Anti-virus treatment for these patients was insufficient.Here we reported the therapy effect of sirolimus,an immunosuppressor,combined with oseltamivir and corticosteroid for a puerpera with severe pneumonia caused by pH1N1 virus.This patient has infected with the pH1N1 virus in late pregnancy,and antiviral therapy was not implemented timely.She developed severe pneumonia and ARDS rapidly and need receive a cesarean section on the 39th week after pregnancy.After giving birth to a healthy baby,she received a combination of oseltamivir,sirolimus and corticosteroid,and improved in the following days.Moreover,the cytokines in serum and viral loads in BALF decreased significantly.She recovered without infectious symptoms and was discharged.Sirolimus combined with oseltamivir and corticosteroid is likely responsible for lowering the viral loads,reducing the patient's cytokine level,and further improving her clinical outcomes.It provides evidence that adjuvant treatment was beneficial to patients with severe pneumonia induced by the pH1N1 virus.

The impact of sample processing on the rapid antigen detection test for SARS-CoV-2: Virus inactivation, VTM selection, and sample preservation

Many factors have been identified as having the ability to affect the sensitivity of rapid antigen detection(RAD)tests for severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).This study aimed to identify the impact of sample processing on the sensitivity of the RAD tests.We explored the effect of different inactivation methods,viral transport media(VTM)solutions,and sample preservation on the sensitivity of four RAD kits based on two SARS-CoV-2 strains.Compared with non-inactivation,heat inactivation significantly impacted the sensitivity of most RAD kits;however,β-propiolactone inactivation only had a minor effect.Some of the VTM solutions(VTM2,MANTACC)had a significant influence on the sensitivity of the RAD kits,especially for low viral-loads samples.The detection value of RAD kits was slightly decreased,while most of them were still in the detection range with the extension of preservation time and the increase of freeze–thaw cycles.Our results showed that selecting the appropriate inactivation methods and VTM solutions is necessary during reagent development,performance evaluation,and clinical application。