[Association between high-density lipoprotein cholesterol level and cardiovascular disease and all-cause mortality in the elderly population].

Objective: To investigate the relationship between high density lipoprotein cholesterol (HDL-C) and cardiovascular disease (CVD) and all-cause mortality in the elderly population. Methods: A total of 14 355 elderly persons aged ≥65 years, who participated in the annual physical examination in Kailuan Group in 2006 were included in this prospective cohort study. According to HDL-C level, the participants were divided into 4 groups: low-level group (HDL-C<1.30 mmol/L), intermediate-level group (1.30 mmol/L ≤HDL-C≤1.54 mmol/L), medium-high-level group (1.55 mmol/L ≤HDL-C≤1.80 mmol/L), high-level group (HDL-C≥1.81 mmol/L). Baseline data such as age, sex and blood lipid levels were collected and compared. Inpatient medical records and death information were obtained through the social security system, and CVD and all-cause mortality were analyzed. After adjusting for confounding factors, the medium-high-level group was used as the reference group. Cox proportional risk regression model was used to evaluate the impact of HDL-C on CVD and all-cause mortality events. The linear or nonlinear relationship between HDL-C level and CVD and all-cause mortality events was evaluated by restricted cubic spline regression model. Death competitive risk analysis was conducted, and sensitivity analysis was performed after excluding subjects with CVD or all-cause mortality within 1 year of follow-up and female participants. Results: The average age of this cohort was (71.5±5.5) years and follow-up time was (10.9±3.3) years. Compared with medium-high-level group, Cox proportional risk regression analysis showed that the HR (95%CI) of CVD and all-cause mortality in low-level group were 1.21 (1.06-1.38) (P<0.05) and 1.02 (0.95-1.11) (P>0.05), respectively; the HR (95%CI) of CVD events in high-level group was 1.17 (1.03-1.33) (P<0.05), and there was a marginal significant association with all-cause mortality, the HR (95%CI) was 1.07 (1.00-1.16) (0.050.1). Conclusions: In the elderly population, the risk of CVD is lowest when the HDL-C level is 1.55-1.80 mmol/L, either high or low HDL-C is a risk factor for CVD. High HDL-C tends to be related to increased risk of all-cause mortality and low HDL-C is not related to increased risk of all-cause mortality.

[The prevalence rate and influencing factors of cough in children under 5 years old in Yiwu city, Zhejiang Province in 2019].

Objectives: To investigate the prevalence of cough and its influencing factors in community children under 5 years old. Methods: From October to December 2019, we selected 3 102 community children under the age of 5 from 50 natural villages/residential communities in 14 towns/streets of Yiwu, Zhejiang Province, using multi-stage random sampling method. A face-to-face and on-site questionnaire survey was conducted among child caregivers to collect demographic data and information about children's cough in the last 1 month. Multiple logistic regression model was used to analyze children's cough and the influencing factors of different cough states. Results: Multivariate logistic regression model analysis results showed that compared with 0-1 year old, dispersed, caregivers with education level below high school, families with 1 child under 5 years old, Cough risk was higher in 1-2, 2-3, 3-4 years old, nurseries, caregivers with education level of high school or above, and families with more than 2 children under 5 years old. OR (95%CI) values were 1.52(1.19-1.92), 1.65(1.29-2.10), 1.86(1.36-2.54), 2.59(1.99-3.38), 1.48(1.26-1.74) and 1.35(1.13-1.62), respectively. Further analysis of the influencing factors of different states of cough, multivariate logistic regression model analysis results showed that preschool status, the number of children under 5 years old in the family and the education level of caregivers were the influencing factors of acute, prolonged and chronic cough. Age was only an influencing factor of acute and persistent cough. Conclusions: The disease burden of cough in children under 5 years old community was heavy, and the cough was related to children's age, education level of caregivers, number of children under 5 years old in the family and childcare status.

[Study on maternal-fetal status of Pb, Cd, As, Hg, Mn and Se elements and transplacental transfer efficiency].

Objective: To understand the levels of Pb, Cd, As, Hg, Mn, and Se in maternal and umbilical cord blood, and to explore the transplacental transfer efficiency (TTE). Methods: From September 2010 to December 2013, a total of 773 pregnant women and their newborns (Laizhou Bay Birth Cohort) were recruited from a second grade hospital in the south bank of Laizhou Bay, Bohai, Shandong Province. According to different detection methods, the six measured elements are classified into three groups including the Hg measurement group (595 mother-newborn pairs), the Pb measurement group (534 mother-newborn pairs), and the Cd, As, Mn and Se measurement group (244 mother-newborn pairs). The demographic characteristics of pregnant women and their newborns were obtained by the questionnaire. The concentrations of elements in maternal and umbilical cord blood were detected and the TTE of each element (elemental concentration in cord blood/elemental concentration in maternal blood) was calculated. The correlation of elements between maternal and cord blood was analyzed using Spearman's rank correlation coefficient. Results: The mean±SD of maternal age, gestational week and newborn birth weight of 773 mother-infant pairs were (28.34±4.50) years, (39.47±1.39) weeks and (3 419.47±497.39) g respectively. The median concentrations of Pb, Cd, As, Hg, Mn and As in maternal and cord blood were 31.12 and 30.02, 1.19 and 0.47, 8.05 and 6.03, 0.69 and 1.26, 100.70 and 105.55, 127.25 and 115.00 µg/L, respectively. The TTE of Pb, Cd, As, Hg, Mn, and Se was 0.98, 0.41, 0.73, 1.73, 0.96 and 0.91, respectively. Pb, Cd, Hg, Mn, and Se showed a significant positive correlation between maternal blood and cord blood, with Spearman correlation coefficients of 0.397, 0.298, 0.698, 0.555, and 0.285 (all P values<0.001). Conclusion: Each element was commonly detected in maternal blood and cord blood. The TTE of Hg was the highest.

[Comparison of arterial stiffness in non-hypertensive and hypertensive population of various age groups].

Objective: To investigate the impact of blood pressure and age on arterial stiffness in general population. Methods: Participants who took part in 2010, 2012 and 2014 Kailuan health examination were included. Data of brachial ankle pulse wave velocity (baPWV) examination were analyzed. According to the WHO criteria of age, participants were divided into 3 age groups: 18-44 years group (n=11 608), 45-59 years group (n=12 757), above 60 years group (n=5 002). Participants were further divided into hypertension group and non-hypertension group according to the diagnostic criteria for hypertension (2010 Chinese guidelines for the managemengt of hypertension). Multiple linear regression analysis was used to analyze the association between systolic blood pressure (SBP) with baPWV in the total participants and then stratified by age groups. Multivariate logistic regression model was used to analyze the influence of blood pressure on arterial stiffness (baPWV≥1 400 cm/s) of various groups. Results: (1)The baseline characteristics of all participants: 35 350 participants completed 2010, 2012 and 2014 Kailuan examinations and took part in baPWV examination. 2 237 participants without blood pressure measurement values were excluded, 1 569 participants with history of peripheral artery disease were excluded, we also excluded 1 016 participants with history of cardiac-cerebral vascular disease. Data from 29 367 participants were analyzed. The age was (48.0±12.4) years old, 21 305 were males (72.5%). (2) Distribution of baPWV in various age groups: baPWV increased with aging. In non-hypertension population, baPWV in 18-44 years group, 45-59 years group, above 60 years group were as follows: 1 299.3, 1 428.7 and 1 704.6 cm/s, respectively. For hypertension participants, the respective values of baPWV were: 1 498.4, 1 640.7 and 1 921.4 cm/s. BaPWV was significantly higher in hypertension group than non-hypertension group of respective age groups (P<0.05). (3) Multiple linear regression analysis defined risk factors of baPWV: Multivariate linear regression analysis showed that baPWV was positively correlated with SBP(t=39.30, P<0.001), and same results were found in the sub-age groups (t-value was 37.72, 27.30, 9.15, all P<0.001, respectively) after adjustment for other confounding factors, including age, sex, pulse pressure(PP), body mass index (BMI), fasting blood glucose (FBG), total cholesterol (TC), smoking, drinking, physical exercise, antihypertensive medications, lipid-lowering medication. (4) Multivariate logistic regression analysis of baPWV-related factors: After adjustment for other confounding factors, including age, sex, PP, BMI, FBG, TC, smoking, drinking, physical exercise, antihypertensive medication, lipid-lowering medication, multivariate logistic regression analysis showed that risks for increased arterial stiffness in hypertension group were higher than those in non-hypertension group, the OR in participants with hypertension was 2.54 (2.35-2.74) in the total participants, and same results were also found in sub-age groups, the ORs were 3.22(2.86-3.63), 2.48(2.23-2.76), and 1.91(1.42-2.56), respectively, in each sub-age group. Conclusion: SBP is positively related to arterial stiffness in different age groups, and hypertension is a risk factor for increased arterial stiffness in different age groups. Clinical Trial Registry Chinese Clinical Trial Registry, ChiCTR-TNC-11001489.

A cross-sectional study of acute diarrhea in Pudong, Shanghai, China: prevalence, risk factors, and healthcare-seeking practices.

Diarrhea is a common cause of morbidity and mortality and the incidence of diarrhea in the world has changed little over the past four decades. To assess the prevalence of and healthcare practices for diarrhea, a cross-sectional study was conducted in Pudong, Shanghai, China. In October 2014, a total of 5324 community residents were interviewed. Respondents were asked if they had experienced diarrhea (defined as ⩾3 passages of watery, loose, bloody, or mucoid stools within a 24-h period) in the previous month prior to the interview. The monthly prevalence of diarrhea was 4·1% (95% CI: 3·3-4·8), corresponding to an incidence rate of 0·54 episodes per person-year. The proportion of individuals with diarrhea who sought healthcare was 21·2% (95% CI: 13·4-29·0). Diarrhea continues to impose a considerable burden on the community and healthcare system in Pudong. Young age and travel were identified as predictors of increased diarrhea occurrence.

Effects of mutant TDP-43 on the Nrf2/ARE pathway and protein expression of MafK and JDP2 in NSC-34 cells.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects motor neurons and lacks an effective treatment. The disease pathogenesis has not been clarified at present. Pathological transactive response DNA-binding protein 43 (TDP-43) plays an important role in the pathogenesis of ALS. Nuclear translocation of nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) is found in a mutant TDP-43 transgenic cell model, but its downstream antioxidant enzyme expression is decreased. To elucidate the specific mechanism of Nrf2/ARE (antioxidant responsive element) signaling dysfunction, we constructed an ALS cell model with human mutant TDP-43 using the NSC-34 cell line to evaluate the impact of the TDP-43 mutation on the Nrf2/ARE pathway. We found the nuclear translocation of Nrf2, but the expression of total Nrf2, cytoplasmic Nrf2, and downstream phase II detoxifying enzyme (NQO1) was decreased in NSC-34 cells transfected with the TDP-43-M337V plasmid. Besides, TDP-43-M337V plasmid-transfected NSC-34 cells were rounded with reduced neurites, shortened axons, increased levels of intracellular lipid peroxidation products, and decreased viability, which suggests that the TDP-43-M337V plasmid weakened the antioxidant capacity of NSC-34 cells and increased their susceptibility to oxidative damage. We further showed that expression of the MafK protein and the Jun dimerization protein 2 (JDP2) was reduced in TDP-43-M337V plasmid-transfected NSC-34 cells, which might cause accumulation of Nrf2 in nuclei but a decrease in NQO1 expression. Taken together, our results confirmed that TDP-43-M337V impaired the Nrf2/ARE pathway by reducing the expression of MafK and JDP2 proteins, and provided information for further research on the molecular mechanisms of TDP-43-M337V in ALS.

[The correlation of brachial ankle pulse wave velocity with arterosclerosis at different estimated levels of glomerular filtration rate].

To explore the relationship between brachial ankle artery pulse wave velocity of the (baPWV) in different estimation GFR (eGFR) groups and atherosclerosis.In 2010, 2012 and 2014, eGFR and baPWV were detected in 1 427 healthy persons.As eGFR level decreased, baPWV increased accordingly with higher proportion of baPWV ≥1 400 cm/s.The percentage of eGFR lower than 60 ml·min-1·1.73 m-2 was similar in subgroups with different baPWV.However, the proportion of eGFR reduction≥30% decreased according to the elevation of baPWV.Multivariate logistic regression analysis indicated the lower the eGFR, the higher the risk of atherosclerosis.Low eGFR is an independent risk factor for atherosclerosis.

[Research advances in epithelial - mesenchymal transition in hepatocellular carcinoma].

Epithelial-mesenchymal transition (EMT) is a process by which epithelial cells lose their own features and become mesenchymal cells, and more and more studies have shown that EMT plays an important role in the invasion and metastasis of hepatocellular carcinoma (HCC). This article reviews the signaling pathways involved in the progression of HCC and molecules involved in the regulation of EMT, in order to provide a new direction for the treatment of HCC.

[Cluster analysis of the clinical presentations in patients with moderate-to-severe obstructive sleep apnea syndrome and its significance].

OBJECTIVE: To analyze subtypes of the clinical presentation of moderate-to-severe obstructive sleep apnea syndrome (OSAS) by cluster analysis and to explore its significance. METHODS: A retrospective analysis was performed on the data of adult moderate-to-severe OSAS patients, which were diagnosed in Respiratory Department, Renmin Hospital of Wuhan University from October 2012 to October 2015. Fifteen kinds of clinical presentations were included in the cluster analysis, and analysis of characteristic of each cluster was then performed after category. RESULTS: Patients were classified as three distinct clusters. They were identified as "daytime sleepiness group" , "night insomnia group" and "minimally symptomatic group" , consisting of 450 cases (44.64%), 351 cases (34.82%) and 207 cases (20.54%) of the entire cohort. Members in daytime sleepiness group had the highest probability of daytime sleepiness, tiredness, irritableness and the highest Epworth Sleeping Scale score[329 cases (73.11%), 280 cases (62.22%), 223 cases (49.56%) and (13.50±4.93) points], members in night insomnia group had the highest probability of complaining of insomnia, nocturia, night sweats, apnea and awakening[177 cases (50.43%), 157 cases (44.73%), 130 cases (37.04%), 296 cases (84.33%), 182 cases (51.85%)], the probability of having typical symptoms above was the lowest in minimally symptomatic group, but these patients were more likely to have related comorbidities: hypertension, coronary heart disease, arrhythmia, chronic obstructive pulmonary disease and gastroesophageal reflux disease[118 cases (57.00%), 41 cases (19.81%), 44 cases (21.26%), 34 cases (16.43%), 38 cases (18.36%)]; all above results were significantly higher than the other two groups (P<0.012 5). The rate of diabetes in minimally symptomatic group[28 cases (13.53%)]was also higher but the difference was not statistical significance. CONCLUSION: Cluster analysis contributes to classify multiple clinical presentations of OSAS patients, which has important significance for recognizing disease heterogeneity and early diagnosis.

[Monitoring and research on pathogen spectrum in patients with acute diarrhea from sentinel hospital of Zhejiang Province during 2009 to 2014].

Objective: To explore pathogen spectrum constitution of acute diarrhea in outpatient and emergency of Zhejiang Province, and provide basis for treatment, prevention and control of the disease. Methods: During January 2009 to December 2014, we selected seven sentinel hospitals in different regions of Zhejiang, monitored and researched on pathogen spectrum in patients with acute diarrhea from outpatient and emergency. We recorded patients' personal basic information, the main symptoms and signs, and collected stool samples (5 g). Eight kinds of bacteria (Vibrio cholerae, Shigella spp., Salmonella spp., Diarrheagenic E. coli, Vibrio parahaemolyticus, Aeromonas hydrophila, Yersinia enterocolitica and Plesiomonas shigelloides) and five kinds of viruses (Rotavirus, Norovirus, Sappovirus, Astrovirus and Adenovirus) were detected. Chi-square test and Fisher's exact probability method were used to compare different characteristics of patients with single bacterial infection, single virus infection and multiple infection (bacteria-bacteria, bacteria-viruses, virus-virus). Results: During 2009 to 2014, 9 364 fecal samples from acute diarrhea patients were collected and tested, among which 3 500 cases were tested positive, with total positive rate of 37.38%. Positive rates of bacteria and viruses were 13.14% (1 230 cases) and 20.75% (1 943 cases), respectively. Mixed infection positive rate of multiple pathogens was 3.49% (327 cases). Positive rate of Vibrio parahaemolyticus (5.96% , 558 cases) was the highest among bacterial pathogens, followed by pathogenic Escherichia coli (3.86%, 361 cases). Viruses were mainly Norovirus (10.73%, 1 005 cases) and rotavirus (8.35%, 782 cases). A big difference existed in diarrheogenic pathogen spectrum between patients less than 15 years old and patients equal or older than 15 years old. Pathogens for patients less than 15 years old were mainly virus, with the positive rate of 32.69% (1 014 cases). However, the positive rate of bacteria was 16.86% (1 056 cases) in patients equal or older than 15 years old. Single bacterial infection was highest in age group of 25-34 years old (18.62%, 302 cases) , single virus infection was highest in age group of 1-4 years old (41.12%, 435 cases) , and mixed infections of multiple pathogens were mainly existed in age group of 1-4 years old (7.37%, 78 cases) . Pathogen positive rate were increasing year by year. Pathogen positive rate of patients with acute diarrhea has obvious seasonality, with single bacterial infection being highest during July to September and single virus infection being highest during December to March. Pathogen spectrum of outpatient and emergency patients with acute diarrhea in Zhejiang Province changed a little from 2009 to 2014, mainly rotavirus (22.34% (782/3 500)), norovirus (28.71% (1 005/3 500)), vibrio parahaemolyticus (15.92% (558/3 500)) and Escherichia coli (10.31% (361/3 500)). However, pathogen spectrums in different years owned different features. Conclusion: Common pathogens in outpatient and emergency patients with acute diarrhea in Zhejiang Province were tested with significant seasonal epidemic law. The composition of pathogenic spectrum was variant in different age group. Constitutes of major pathogen spectrum in different years differed a little.

QSAR of acute toxicity of halogenated phenol to green fluorescent protein by using density functional theory.

A novel approach was established to predict toxicity of environmental pollutants by using green fluorescent protein (GFP) as bio-marker. In the approach, recombinant Escherichia coli was constructed to express GFP. The toxicity values (-lgEC (50)) of 14 halogenated phenols to recombinant E. coli with GFP gene were measured. And optimized calculation was carried out at B3LYP/6-31G* level using density functional theory method. Based on the MTLSER model, the obtained parameters were taken as theoretical descriptors to establish the novel QSAR model for predicting -lgEC (50) (R (2) = 0.922). The model includes two variables (standard entropy (S (θ)) and the most negative atomic net charges of the molecule (q (-))). The results of cross-validation test (q (2) = 0.868) indicate the model of this study has optimum stability, which shows that it is feasible to predict to toxicity of chemistry utilizing recombinant E. coli with GFP gene.

[Time distribution of positive nucleic acid detection in imported cases infected with SARS-CoV-2 in China].

Objective: To analyze the time distribution of the first positive nucleic acid detection in imported cases infected with SARS-CoV-2 reported nationwide in China and provide references for further improvement of the prevention and control of COVID-19 in international travelers. Methods: The data of imported cases infected with SARS-CoV-2 reported by provinces from 24 July 2020 and 23 July 2021 were collected for the analysis on the time distribution of the first positive nucleic acid detection after entering China. Results: A total of 7 199 imported cases infected with SARS-CoV-2 were reported in 28 provinces during 24 July 2020 to 23 July 2021. The median interval (Q1, Q3) from the entry to the first positive nucleic acid detection of SARS-CoV-2 was 1 (0, 5) day. The imported cases who had the first positive nucleic acid detections within 14 days and 14 days later after the entry accounted for 95.15% (6 850/7 199) and 4.85% (349/7 199) respectively. Among these cases, 3.65% (263/7 199), 0.88% (63/7 199) and 0.32% (23/7 199) had the first positive nucleic acid detections within 15-21 days, 22-28 days and 28 days later after the entry respectively. The proportion of asymptomatic infections were 47.24% (3 236/6 850) and 63.61% (222/349) among the cases who had the first positive nucleic acid detections within 14 days and 14 days later after the entry respectively. A total of 39.54% (138/349) of cases infected with SARS-CoV-2 with the first positive nucleic acid detections 14 days later after the entry had inter-provincial travel after the discharge of entry point isolation. Conclusions: About 5% of the imported cases infected with SARS-CoV-2 were first positive 14 days later after the entry. In order to effectively reduce the risk of domestic COVID-19 secondary outbreaks caused by imported cases, it is suggested to add a nucleic acid test on 8th -13th day after the entry.

[Investigation of incidence of acute respiratory infection and healthcare-seeking behavior in period of COVID-19 epidemic].

Objective: To analyze the incidence of acute respiratory infection (ARI) and related healthcare seeking behaviors in population in the period of COVID-19 epidemic in China. Methods: According to the province specific cumulative incidence rates of COVID-19 reported as of March 31, 2020, the low, medium and high-risk areas were classified. In these areas, a stratified two stage cluster random sampling method was used to select participants for face-to-face questionnaire surveys. Data on the incidence of ARI and related healthcare seeking behaviors in community residents during COVID-19 epidemic period were collected to calculate the attack rate of ARI and related healthcare seeking rate. Logistic regression method was used to explore the influencing factors for ARI incidence and healthcare seeking behavior. Results: A total of 34 857 community residents were surveyed, in whom 647 (1.9%) reported that they had ARI symptoms during the COVID-19 epidemic period, and 241 (37.2%) had healthcare seeking behaviors. In terms of the incidence of COVID-19-related ARI, in high-risk area, the risk of COVID-19-related ARI was 1.36 times (95%CI: 1.12-1.65) than that in low-risk area; among different age groups, the risk of COVID-19-related ARI in age groups 20-39 years, ≥60 years was 1.80 times (95%CI: 1.29-2.59) and 1.63 times (95%CI: 1.14-2.40) than that in age group 1-9 years; the risk of COVID-19-related ARI in people with underlying diseases was 1.53 times (95%CI: 1.23-1.89) than that in those without underlying diseases; the risk of COVID-19-related ARI in people with contacts with confirmed cases of COVID-19 and people with fever or respiratory symptoms was 1.53 times (95%CI: 1.01-2.27) and 6.60 times (95%CI: 5.05-8.53) than those in people without these contacts. The healthcare seeking rate in COVID-19-related ARI patients with exposures to those with fever or respiratory symptoms was 1.68 times (95%CI: 1.05-2.70) than that in such patients without the exposures. Conclusions: The attack rate of COVID-19-related ARI was affected by the local epidemic level of COVID-19, and in high-risk area, the attack rate of COVID-19-related ARI was also high. The healthcare seeking rate in patients with COVID-19-related ARI was low. Therefore, it is necessary to encourage the healthcare seeking in people with ARI in COVID-19 pandemic period.

Aberrant Expression of a Proliferation-Inducing Ligand Underlies Autoimmune Mechanisms in Immune Thrombocytopenia.

PURPOSE: To study the relationship between surface membrane-bound APRIL and ITP. METHODS: The peripheral blood of all subjects, 50 patients diagnosed with ITP and 25 healthy controls, was collected. Flow cytometry was used to detect the expression of membrane-bound APRIL on immune cells and platelets. ELISA was used to detect the content of soluble APRIL in plasma. RESULTS: Membrane-bound APRIL was only expressed on the surface of platelets in both ITP patients and controls. APRIL expression on the platelet surface was significantly lower in newly diagnosed (P < 0.001) and chronic (P < 0.001) ITP patients than in controls. Platelet surface APRIL level was significantly enhanced in patients with complete remission after treatment (P = 0.02) but not in those with no response after treatment. Platelet surface APRIL level in ITP patients was negatively correlated with serum APRIL level (r = -0.09765, P = 0.0424). CONCLUSIONS: Platelet surface APRIL may play a key immunoregulative role. Platelet surface APRIL is likely to be one source of the excessive serum APRIL in ITP patients. The effectiveness of treatment may be measured by determining the platelet surface APRIL levels in ITP patients.

[Advance on the infectivity of SARS-CoV-2 infection at different stages].

The studies on infectiousness of person infected with SARS-CoV-2 at different stages of illness are an important basis for making effective prevention and control measures such as investigating the infectious source, determining the scope of close contacts and the timing of case isolation. This review discusses the infectiousness of cases infected with SARS-CoV-2 in the incubation period, symptomatic period and convalescent period by reviewing national and international literatures, technical and professional guidelines. Existing researches suggest that the infectious viruses could be isolated at the end of the incubation period as well as since illness onset, and viral load in upper respiratory tract swabs reached the peak on day 4-6 after illness onset and thereafter began to decline, implying the infectiousness was relatively strong at the end of incubation period and within one week after illness onset. Although there were a few cases who tested positive for SARS-CoV-2 after recovery, no evidence was found to indicate these cases can cause the transmission.

[Distribution and infectious characteristics of re-positive cases infected with SARS-CoV-2].

Domestic and foreign literatures related to the persistence of SARS-CoV-2 and the re-positive cases infected with SARS-CoV-2 were reviewed, and the characteristics and infectivity of the re-positive cases were analyzed to provide scientific evidence for the improvement of case management and the development of measures to stop the spread of SARS-CoV-2. Existing studies have shown that re-positive rate of SARS-CoV-2 ranged from 2.4% to 19.8%, the median of interval between re-positive detection and discharge was 4-15 days. Following the second course of the disease, the anti-SARS-CoV-2 IgM, IgG and IgA positive rates of the cases were 11.11%-86.08%, 52.00%-100.00% and 61.54%-100.00% respectively, the total antibody and neutralizing antibody positive rates were 98.72% and 88.46%. The viral load of the re-positive cases was lower than that in the initial infection. At least 3 380 re-positive cases have been reported globally. SARS-CoV-2 strains were isolated from the samples of 3 re-positive cases (1 immunodeficiency case and 2 cases with abnormal pulmonary imaging). There were close contacts that were infected by an asymptomatic case taking immunosuppressive agents. In conclusion, the infectivity of re-positive cases infected with SARS-CoV-2 is generally very low. Rare re-positive cases infected with SARS-CoV-2 might cause further transmission. The management approach for the re-positive cases can be based on the assessment of the individual transmission risk according to the pathogen detection results.

[Progress in research of specific antibody dynamic characteristics in patients with COVID-19].

COVID-19 is an emerging infectious disease caused by SARS-CoV-2. After the infection of the virus, the host immune system is stimulated to produce multifarious specific antibodies to decrease or eliminate effects of the pathogen. Study of the specific antibodies dynamic characteristics in patients with COVID-19 is very important for the understanding and diagnosis of the disease, research and development of vaccine, and planning of prevention and control strategy. This paper reviews and summarizes the domestic and oversea research on dynamic characteristics of specific antibodies of COVID-19 patients, including the antibody producing, duration and level, and its possible influencing factors in order to improve the understanding of the immunological characteristics of COVID-19.

Interleukin-27 as a negative regulator of human neutrophil function.

Interleukin-27 (IL-27) is a novel cytokine of the IL-6/12 family with a broad range of immune regulation properties, which has been considered as a potential therapeutic agent for immune diseases and cancers. However, little is known about the effect of IL-27 on human neutrophils before its clinical administration. In this study, we investigated the effects of IL-27 on human neutrophil functions including adhesion, reactive oxygen species (ROS)/cytotoxic granule components production, inflammatory cytokines production, major histocompatibility complex (MHC) molecules expression and neutrophils' survival. We showed that IL-27 receptor complex, WSX-1/TCCR and gp130, is constitutively expressed on human neutrophils. In vitro, IL-27 suppressed neutrophil adhesion in response to fMLP, which might depend on the down-regulation of Mac-1. IL-27 also suppressed lipopolysaccharide-induced ROS production and attenuated cytotoxic granule components production in the cytoplasm of human neutrophils. In addition, IL-27 enhanced the production of IL-1ß but not TNF-α from neutrophils. However, IL-27 failed to regulate the expression of MHC molecules and the survival of human neutrophils. In conclusion, our data demonstrate that IL-27 mainly down-modulates human neutrophil function, which might extend our understanding of the role of IL-27 in the innate immune response.

Ferroelectric P(VDF-TrFE)/POSS nanocomposite films: compatibility, piezoelectricity, energy harvesting performance, and mechanical and atomic oxygen erosion.

Poly(vinylidene difluoride) (PVDF) and its copolymers as the polymers with the highest piezoelectric coefficient have been widely used as sensors and generators. However, their relatively low performances limit their applications in some harsh environments. In this work, piezoelectric poly(vinylidene-trifluoroethylene) P(VDF-TrFE) matrices with different amounts of polyhedral oligomeric silsesquioxane (POSS) were prepared by a low temperature solvent evaporation method and thermal poling. The morphology, surface performance, crystalline phase, and piezoelectric and ferroelectric properties of the nanocomposites were investigated and the influence of POSS on these performances was studied. POSS had good compatibility with P(VDF-TrFE) and did not affect the crystalline phase formation of the matrix. The composites presented good piezoelectric properties. Piezo- and triboelectric nanogenerators were designed and fabricated. The voltage and current outputs were analyzed and the polarization effect was evaluated. The average output voltage and the current density of the matrix were 3 V and 0.5 µA cm-2 when subjected to a force of 38 N on an area of 1 cm2. The mechanical properties of P(VDF-TrFE)/POSS nanocomposites were also studied by the nanoindentation test. The hardness and modulus of samples increased 20% and 17% with a low addition of POSS. Atomic oxygen erosion properties of the composites were numerically simulated by the Monte Carlo method. The erosion cavity shape and depth were compared and studied. The influence of POSS addition on the P(VDF-TrFE) matrix and the associated reinforcing mechanism were analyzed.