Objective:To construct an explainable artificial intelligence(AI) model of risk characteristics of papillary thyroid carcinoma(PTC), and to explore its value of it combined with clinical features in predicting cervical lymph node metastasis(CLNM) in PTC patients.Methods:From January 2021 to September 2022, 422 patients(422 nodules) with pathologically confirmed PTC underwent thyroidectomy and neck lymph node dissection in the Second Affiliated Hospital of Xi′an Jiaotong University were retrospectively collected, the patients were randomly divided into training set and test set according to the ratio of 7∶3. Ultrasonographic features highly correlated with PTC risk characteristics were extracted by traditional machine learning method, and an intelligent prediction model with optimal probability of risk characteristics was established. Then, a risk model for predicting CLNM of PTC patients was constructed in combination with clinical features. The diagnostic effectiveness of the model was evaluated by drawing a ROC curve and calculating the area under curve (AUC).Results:In the AI explaineable model of PTC risk characteristics in the test set, the intelligent diagnosis model of calcification based on logistic regression classification showed the highest diagnostic efficiency, with an AUC of 0.87 ( P<0.05). Compared with the probability model of risk characteristic of PTC alone, the comprehensive model combined with clinical characteristics showed higher diagnostic efficiency in predicting CLNM of PTC patients, with AUC of 0.97, diagnostic critical value of 0.15, corresponding accuracy, sensitivity and specificity of 92.65%, 92.76% and 92.54%, respectively (all P<0.05). Conclusions:The explaineble risk characteristics of PTC AI model combined with clinical features can effectively predict the cervical lymph node metastasis of PTC, and then provide effective information for clinical decision-making of PTC patients.

Objective:To understand the epidemiological characteristics and incidence trend of severe fever with thrombocytopenia syndrome (SFTS) in China.Methods:The incidence data of SFTS in China from 2018 to 2021 were collected from Chinese Disease Prevention and Control Information System for a statistical and descriptive epidemiological analysis by using software such as Excel 2016, Joinpoint 5.0.2, SPSS 26.0, and GraphPad Prism 8.0, especially, the SFTS cases reported monthly by key provinces were analyzed.Results:From 2018 to 2021, a total of 8 835 SFTS cases were reported in 25 provinces and the annual incidence showed an upward trend. The distribution of SFTS cases showed clustering, but the cases were mainly sporadic ones. The cases began to increase in March, mainly occurred during April to October (96.79%,8 551/8 835), and peaked during May to July. The cases were mainly distributed in middle-aged and old farmers, and slight more cases were women. The average case fatality rate was 5.38%, which varied greatly with areas. The case fatality rate tended to increase with age.Conclusion:From 2018 to 2021, the epidemiological characteristics of SFTS in China remained stable, but the number of reported cases gradually increased and the distribution showed an expanding trend, to which close attention should be paid.

Objective:To investigate the prevalence of lymphocytic choriomeningitis virus (LCMV) and hantavirus (HV) specific antibodies among cross-border migrant workers for assessment of the risk of rodents-borne virus infection.Methods:From 2019 to 2020, a survey was conducted on cross border migrant workers engaged in outdoor activities, and serum samples were collected, LCMV specific IgG antibody was detected by an indirect ELISA and Western blot based on recombinant nucleoprotein, and indirect immunofluorescence assay (IFA) based on recombinant expressed glycoprotein. HV IgG antibody in serum was detected by a commercial indirect IgG ELISA kit and IFA based on hantavirus infected Vero cells.Results:A total of 139 cross-border workers, aged 25~57, were surveyed; 64% (89/139) had working experience in multiple countries, involving 26 countries, including 14 countries in Asia and 12 countries in Africa; 11.51% (16/139) of serum samples were tested positive for LCMV antibodies, and the positive samples were verified by Western blot and IFA. The antibody detection rate was slightly higher than the published infection rate from other similar studies. And, HV antibodies were detected from one serum sample (0.72%, 1/139) by ELISA and IFA. However, it was still uncertain when and where the viral infections were acquired.Conclusions:Through this serological cross-sectional preliminary analysis, the infection status and existing risks of LCMV and HV viruses among cross border migrant workers were revealed, which suggested the necessity of strengthening the prevention and control of rodents borne diseases in outdoor engineering sites.

Objective:To compare and analyze the clinical diagnostic values of five thyroid nodule malignant risk stratification guidelines.Methods:From October 2019 to October 2021, 926 cases of patients with 1 027 thyroid nodules were recruited in the Second Affiliated Hospital of Xi ′an Jiaotong University. All nodules were categorized individually according to 2015 American Thyroid Association for Ultrasound Malignancy Risk Stratification of Thyroid Nodules in Adults Guidelines(ATA guidelines), 2016 the Korean Society of Radiology and the Korean Society of Thyroid Radiology Thyroid Imaging Reporting and Data Systems(K-TIRADS), 2017 European Thyroid Association Thyroid Imaging Reporting and Data Systems(Eu-TIRADS), 2017 American College of Radiology Thyroid Imaging Reporting and Data Systems (ACR TI-RADS), and 2020 Chinese Thyroid Imaging Reporting and Data System (C-TIRADS). The pathological results were taken as the gold standard, the malignancy ratio of nodules of different categories in each system was calculated. ROC curves were plotted to evaluate the diagnostic efficiencies of different systems, and DeLong test was used to compare the areas under ROC curves. The sensitivity and specificity of different systems were calculated when the maximum point of the Youden index was the optimal cut-off value.Results:In the same stratified system, there were statistically significant differences in the malignant proportion of nodules of different grades ( P<0.05). The malignant proportion of nodules in the high-risk group showed no significant difference among different stratified systems ( P>0.05). Except for C-TIRADS, the malignant proportion of nodules was increased with the increase of diagnostic grade at each grade of the other four stratification systems. ROC curve showed that AUCs of ATA guidelines, K-TIRADS, EU-TIRADS, ACR TI-RADS and C-TIRADS were 0.814, 0.819, 0.814, 0.820 and 0.802, respectively, there was no statistical significance in AUC of different stratification systems (all P>0.05). The optimal truncation values in differentiating benign and malignant nodules were middle-risk malignant nodules, moderately suspicious malignant nodules, middle-risk malignant nodules, class 4 and class 4B. The diagnostic of five stratification systems showed that ATA guidelines had the highest sensitivity (0.784), C-TIRADS had the highest specificity (0.854). Conclusions:The five stratified systems have similar efficacy in differentiating benign and malignant thyroid nodules, and all of them have good diagnostic value.

Objective:To establish a quick on-site emergency detection method for severe fever with thrombocytopenia syndrome virus (SFTSV), dengue virus (DENV), and hantaan virus (HTNV).Methods:This research was based on the traditional TaqMan fluorescent probe technology, using the domestic rapid one-step quantitative RT-PCR kit, combined with the Magnetic induction cycler (Mic) qPCR instrument. The detection limit, specificity and repeatability of this method were evaluated by simulated samples, other virus infected samples and normal human blood samples.Results:Compared with the traditional RT-PCR assay, the required time of this method was greatly shortened, and the detection can be completed within 35 minutes. The limit of quantitation for SFTSV, DENV and HTNV are less than 100copies/PCR. No nonspecific amplification was found in the simulated negative samples and other virus infected samples. All the simulated positive sample for verification could be detected, and coefficient of variation Ct value of each group was less than 4%. Conclusions:The rapid fluorescence quantitative RT-PCR assays have certain application prospects for on-site emergency detection, and provide important technical supports and new directions for the prevention and control of common hemorrhagic fever viruses.

Objective:To establish real-time fluorescent quantitative RT-PCR method for detection of Avalon virus (AVAV) and Hughes virus (HUGV), two Nairoviruses in the family of Nairoviridae. Methods:The genomic sequences of the two viruses published in the international public database were collected, collated, compared and analyzed to define the detection targets, and the viral specific primers and probes were designed accordingly. Real-time fluorescent quantitative RT-PCR detection method were established, and the operating detection procedures were optimized using simulated samples prepared using in vitro transcription assay, other virus infected samples, virus strains and normal human blood samples. The detection limit, specificity and repeatability of the method were evaluated.Results:The real-time fluorescent quantitative RT-PCR method could effectively amplify and detect AVAV and HUGV viral target RNA with detection limits of about 20 copies/μl and 70 copies/μl, respectively. No nonspecific amplification was found in the samples of Kyasanur forest disease virus, influenza B virus BV and BY, influenza A virus H3N2, yellow fever virus, Japanese encephalitis virus, Crimean-Congo hemorrhagic fever virus, SFTS virus, nairobi sheep disease virus and Tahyna virus. There was no cross reaction between the two nairoviruses. The coefficient of variation was within 2% by repeated comparative analysis.Conclusions:The real-time fluorescent quantitative RT-PCR method for detection of AVAV and HUGV might be used for screening of humans, vectors and host animal samples for rapid detection of related pathogens.

Objective:To develop a rapid nucleic acid detection method for Zika virus (ZIKV), Dengue virus (DENV), Yellow fever virus (YFV), Chikungunya virus (CHIKV) based on microfluidic fluorescence quantitative RT-PCR technologies, in order to achieve rapid diagnosis of these four viral infections.Methods:Four sets of specific primers and probes were designed targeting the NS1 gene of ZIKV, the NS5 gene of DENV, and YFV, the E1 gene of CHIKV, respectively. The sensitivity was evaluated using in vitro transcribed RNA of ZIKV, DENV, YFV and CHIKV, and the specificity were evaluated using other viral nucleic acid. ZIKV, YFV and CHIKV detection method were verified using simulated positive samples, and DENV detection method was verified using clinical patient samples, the result of which were also compared with the quantitative RT-PCR detection method . Results:The limit of detection (LOD) of ZIKV, DENV, YFV, and CHIKV microfluidic qRT-PCR method were 14.57 copies/μl, 94.27 copies/μl, 8.25 copies/μl, and 223.19 copies/μl, respectively, and the four detection method showed no cross-reactivity with other viral nucleic acids. The prepared ZIKV, YFV and CHIKV simulated positive samples were 100% detected, and the variation coefficient of Ct value measured at each concentration were all around 2%; the 20 clinical patient specimens of DENV infection were 100% detected, which is consistent with the result of fluorescent quantitative RT-PCR detection.Conclusions:The ZIKV, DENV, YFV, and CHIKV microfluidic quantitative RT-PCR detection method showed good sensitivity, specificity, and stability. The detection could be completed within 25 minutes, which could be used for laboratory detection and early diagnosis.

Objective: To obtain the optimum of lentiviral library packaging based on CRISPR/cas9 (Clustered regularly interspaced short palindromic repeat sequences/CRISPR-associated protein 9). Methods: Reverse transcription polymerase chain reaction (RT-PCR), immunofluorescence antibody (IFA) and enzyme linked immunosorbent assay (ELISA) were used to detect the lentivirus titers in condition of different ratio of packaging plasmids, different addition of lipofectamine 3000 reagent and different time points post-transfection. Then, high-throughput sequencing was performed to evaluate the representation and distribution of single guide (sg)RNAs in the library. Results: The lentivirus titer was the highest when the molar ratio of psPAX2∶pMD2.0G∶Lentivirus library was 2∶1∶1, and the optimum addition of Lipofectamine 3000 reagent was 10 μl, while the result of ELISA were correspondent to that of RT-PCR. The IFA result showed that the lentivirus titer was the highest at 60 h post-transfecion. The coverage of sgRNAs in the lentivirus library packaged with the optimum we obtained was 99.3%, and the read counts of sgRNAs was observed in a normal distribution. Conclusions The optimal lentivirus library packaging was obtained, and this can provide basis for CRISPR/cas9-based screening.

Objective: To establish a method for the simultaneous identification of Zika, Chikungunya and Mayaro viruses. Methods: The complete genome sequences of Zika, Chikungunya and Mayaro virus were retrieved from Global Shared Database for comparative analysis, estimate its conservative region and determine the target gene location, specific primers and probes were designed, then a triplex real-time RT-PCR assay was developed. The specificity, sensitivity and repeatability of the assay were assessed by viral nucleic acid of Zika virus, Chikungunya virus a, in vitro transcriptional RNA of Mayaro virus, normal human serum and related virus simulation sample. Results: The result showed that the established method could detect Zika virus, Chikungunya virus, as well as simulated Mayaro virus samples, the limit of detection (LOD) of Zika and Chikungunya virus was 16.22 Copy/PCR and 12.02 Copy/PCR, respectively, the LOD for simulated Mayaro virus RNA was 2.82 Copy/PCR, no significant difference was detected between the triplex and monoplex assays. No cross reaction was found in the detection of dengue virus, Hantavirus, severe fever with thrombocytopenia syndrome (SFTS) virus, yellow fever virus and influenza virus, and 100 healthy adults blood samples, the specificity of the method was 100%. The repeatability result showed that the standard deviation of all three detections were blow 0.5 and the coefficient of variation was less than 2% by selecting viral nucleic acids or transcribed RNA with high, medium and low concentration gradients. Conclusions A triplex real-time RT-PCR assay for detection of Zika, Chikungunya and Mayaro virus has been established with an acceptable specificity, sensitivity and repeatability.

Objective: To establish a fluorescent bead-based multiplex assay for the simultaneous detection of seven viral diseases endemic in Africa. Methods: The genomic sequences of the viral pathogens causing Rift valley fever, Yellow fever, Marburg virus disease, Ebola virus disease, Lassa fever, Crimean-Congo hemorrhagic fever and Chikungunya fever were compared, PCR detection target fragments were selected, and amplification primers and hybrid probes were designed. The reference samples of related pathogens were prepared by chemical synthesis of DNA and in vitro transcription RNA. The sensitivity and stability of the detection method were evaluated. The specificity was evaluated by testing 30 samples of suspected dengue fever, and hantavirus diseases, and 32 healthy human blood samples. Results: The fluorescent bead-based multiplex assay could specifically detect the corresponding pathogen, the detection limit was at a range of 10²-10⁵ copies/ μl, the specificity was 100%, and the intra-assay coefficient of variation was below 12%, and the inter-assay coefficient of variation was below 15%. Conclusions A fluorescent bead-based multiplex PCR assay for the simultaneous detection of seven viral diseases endemic in Africa was established, which may provide a new choice for the screening of suspected infectious diseases.