Study on the Online Learning Evaluation Based on 2D and 3D Image Processing Technology

In recent years, the outbreak of the COVID-19 epidemic has posed a serious threat to the life safety of people around the world, which has also led to the development of a series of online learning assessment technologies. Through the research and development of a variety of online learning platforms such as WeChat, Tencent Classroom and Netease Cloud Classroom, schools can carry out online learning assessment, which also promotes the rapid development of online learning technology. Through 2D and 3D recognition technology, the online learning platform can recognize face and pose changes. Based on 2D and 3D image processing technology, we can evaluate students' online learning, which will identify students' learning state and emotion. Through the granulation of teaching evaluation, online learning platform can accurately evaluate and analyze the teaching process, which can realize real-time teaching evaluation of students' learning status, including no one, many people, distraction and fatigue. Through relevant algorithms, the online learning platform can realize the assessment of students' head posture, which will give real-time warning of learning fatigue. Firstly, this paper analyzes the framework of online learning quality assessment. Then, this paper analyzes the face recognition and head pose recognition technology. Finally, some suggestions are put forward. © 2023 SPIE.

Research on Influence Factors of Prevention and Control Measures on Economy-based on Netlogo Simulation and Big Data Computation

Emergencies have a significant impact on the economy. Thus, effective prevention and control measures can reduce economic losses to the greatest extent. Taking the novel coronavirus outbreak as the starting point, we proposed the SEEIR-E model, an optimization model of the SEIR. The model compares two different prevention and control modes, 'fence mode' and 'free-range mode' Combined with the big data of the epidemic, systematic simulation and analysis were carried out in the Netlogo simulation environment. When environmental factors are the same, the 'fence model' can control the spread of the disease more quickly, and the economic impact is less. At the same time, the impact of various environmental factors on economic recovery was simulated and analyzed. The result provides a basic understanding in economic recovery after the epidemic. © 2022 IEEE.

Influence of institutional differences on trade credit use during pandemics

This study examines the formal and informal institutions that affected trade credit during the pandemic periods. To this end, we analyze 590,025 firm-year observations across 107 countries during six recent pandemic crises: SARS (2003), H1N1 (2009), MERS (2012), Ebola (2014), Zika (2016), and COVID-19 (2020). The study finds that formal legal institutions and firms' information transparency during pandemic periods act as a "brake” for trade credit usage. By contrast, informal institutions with religious connotations or attributes, social trust, and policy stability play a "cushion” role in softening the impact of pandemic crises when a firm applies for trade credit. These results remain robust after alternating the estimation techniques, trade credits, pandemic variables, and different samples. This study offers new evidence on the role of trade credit from the perspectives of formal and informal institutions during pandemic crises. The outcomes thus provide information worthy of consideration by policymakers when faced with informal institutional conditions and support government efforts to improve unstable formal systems and prevent severe shocks in the future. © 2022

Futures hedging in crude oil markets: A trade-off between risk and return

Risk and return are two fundamentals that have an impact on an investor's or hedger's investing choices. Based on the proposed synchronous movement intensity index, this paper aims to improve the hedging performance by adjusting the model-driven hedge ratio and realize the trade-off between return and risk in futures hedging. First, without loss of generality, we forecast crude oil spot and futures volatility using 10 GARCH-type models, including three linear models and seven nonlinear models, to obtain the ex-ante hedging ratio under the minimum variance framework. Then, we develop a novel and tractable method to identify the market state based on the index of consistency intensity, in which the index portrays the synchronous degree of stock price movements in the energy sector. Last but not least, we propose the hedge ratio adjustment criteria based on the identified state, and adjust the ratio driven by GARCH-type models of futures in accordance with the market state. Empirical results of crude oil futures markets indicate that the proposed state-dependent hedging model is superior to the commonly used models in terms of three criteria including mean of returns, variance, and ratio of mean to variance of returns for measuring hedging effect. We apply the DM test to make a statistical inference and discover that while the mean and the ratio of mean to variance of returns are increasing, the variance and hedging effectiveness of the hedged portfolio based on the modified methods are not significantly affected. Furthermore, the superiority of the proposed method is robust to different market conditions, including significant rising or falling trends, large basis, and COVID-19 pandemic. We also test the robustness of the proposed method with respect to the baseline model, quantile, and evaluation window. Overall, this paper provides a more realistic approach for crude oil risk managers to hedge crude oil price risk, some corresponding implications are also concluded. © 2022 Elsevier Ltd

Analysis of air pollution characteristics, transport pathways and potential source areas identification in Beijing before, during and after the COVID-19 outbreak

A series of lockdown measures in response to the Corona Virus Disease 2019 (COVID-19) outbreak resulted in a drop in anthropogenic emissions and changes in concentrations of PM2.5 and O-3. Backward trajectories analysis, cluster analysis, potential source contribution function (PSCF) and concentration weighted trajectory (CWT) technologies were conducted to reveal the characteristics and potential source areas of pollutants in Beijing before the COVID-19 outbreak (BCO period), during the outbreak (COB period) and after the outbreak (ACO period), as well as the contemporaneous period in 2019 (CCO period), which is critical for exploring the efficient control measures and making policy. The results indicated that despite the significant reduction in anthropogenic emissions during the epidemic, the PM2.5 concentrations increased by 1.0% caused by unfavorable meteorological conditions. O-3 concentrations increased by 174.8% compared to that during the BCO period due to the increased temperature and inappropriate precursor reduction ratios. A considerable decrease of NO3- in PM2.5 was observed under the influence of significant reductions in vehicle emissions during the lockdown. The cluster analysis revealed that short-range transport played a significant role in the accumulation of local PM2.5 pollution, while long-range northwest airflows contributed more to O-3 accumulation, and weakened as the season changed. The PSCF and CWT analysis demonstrated that potential source areas of PM2.5 were mostly located in the central and southern Hebei, the southwestern Shandong in the CCO period, and expanded to central Inner Mongolia and northern Shanxi in the COB period. These areas were highly compatible with the high emission areas of the emission inventory statistics. After the outbreak, the source areas of O-3 were centered in the Beijing-Tianjin-Hebei region and Shandong province, with a radial dispersion in all directions, while they were distributed in the central Mongolia and Inner Mongolia during the other periods.

A Bibliometric research on hot papers of pharmacology & toxicology based on ESI

Objectives: In order to provide useful reference information for researchers in the field of pharmacology and toxicology, this paper studies the current research hot spots in this field, as well as the correlation closeness between research topics. Methods: This paper studies on the hot papers of pharmacology and toxicology field based on ESI (Essential Scientific Indicators) database, and the time span of the data is from January 1, 2010 to December 31, 2020. The data about these 110 hot papers are analyzed by the authors from the aspects of published time, country/territory, institution, journal, citation, and so on. The methods of multi-dimension analysis, cluster analysis, Vosviewer visualization are used to analyze these papers. Results: The results shows that United States is in the first place in the ranking of published papers, England is in the second place, and China is in the third place. The research hotspots are COVID-19, anxiety, depression, and mental health. Conclusions: The cluster of hot papers show the correlativity of the topic in the pharmacology and toxicology field. This research provides researchers in the field of pharmacology and toxicology with the current international hot research direction, and helps China researchers to improve their research in the field.

[Analysis on infectivity of COVID-19 patients before and after last negative nucleic acid test].

Objective: To investigate the infection rate in close contacts of COVID-19 patients before and after the last negative nucleic acid test, evaluate the effect of dynamic nucleic acid test in determining the infectivity of COVID-19 patients. Methods: Dynamic nucleic acid test results of COVID-19 cases were collected in a retrospective cohort study. COVID-19 cases with negative nucleic acid test results before their first positive nucleic acid tests were selected as study subjects. Close contacts of the index cases and the secondary close contacts were kept isolation for medical observation to assess their risk of infection. Results: This study included 89 confirmed cases from two local COVID-19 epidemics in Ningbo. A total of 5 609 close contacts were surveyed, the overall infection rate was 0.20%. No close contacts of the COVID-19 cases before the last negative nucleic acid test were infected, and the infection rate in the close contacts of the COVID-19 cases after the last negative nucleic acid test was 1.33%, all of these close contacts lived together with the index cases. No secondary close contacts were infected. Conclusion: COVID-19 patient becomes infectious after the last nucleic acid is negative, and has no infectivity before the last nucleic acid negative.

EFFECTIVENESS OF LILLY CONNECTED CARE PROGRAM IN IMPROVING GLYCEMIC MANAGEMENT AMONG CHINESE TYPE 2 DIABETES PATIENTS: A RETROSPECTIVE REAL-WORLD STUDY

Background and Aims: Mobile health management platform is a potential way to achieving effective glycemic control in type 2 diabetesmellitus (T2DM) patients, especially during the Covid-19 pandemic. Lilly Connected Care Program (LCCP) is a smartphone-based app providing blood glucose monitoring and diabetes education services to improve diabetes management. This study aimed to evaluate the real-world effectiveness of LCCP platform in glycemic control among Chinese T2DM patients. Methods: This retrospective study included Chinese T2DM patients (age ≥18 years) from January 1, 2015, to January 31, 2020. Data was drawn from mobile app and electronic medical records. Propensity score matching (PSM) was used to match LCCP group and non-LCCP group to reduce confounding, with covariates including age, sex, duration of diabetes, baseline HbA1c, and number of oral diabetes medication classes. We analyzed HbA1c reduction within an average of 4 months and compared the proportions of patients achieving HbA1c reduction ≥0.5% or ≥1% between LCCP and non-LCCP groups. Comparisons were made using independent t-test and Chi-square test. Results: A total of 923 patients were included, among whom 303 pairs of patients were well-matched after PSM (Standardized Mean Difference of covariates <15%). The HbA1c reduction during 4-month follow-up was significantly larger in LCCP group than non-LCCP group (Mean±SD: 2.21 ± 2.37% vs. 1.65 ± 2.29%, P = 0.003). LCCP group had higher proportions of patients with HbA1c reduction ≥1% (69.0% vs. 57.4%, P = 0.003) and ≥0.5% (75.6% vs. 68.0%, P = 0.038). Conclusions: LCCP mobile platform was effective in glycemic control among Chinese T2DM patients in the real world.

To Better Serve and Grow the ComSoc Community

It is a great honor and privilege for me to serve as the President of IEEE Communications Society (ComSoc) in 2022-2023. IEEE ComSoc is a global professional organization that has been creating cutting-edge communications and networking technologies through its high-quality publications, premier conferences, technology standards, educational activities, and membership development. However, we face many new challenges in this era of rapid changes, especially due to the current COVID-19 pandemic. As President, I strive to build upon the outstanding achievements of our past presidents, volunteer leaders, supporting staff, and members to make IEEE ComSoc stronger and to better serve our members.

Association between the COVID-19 pandemic and fetal, neonatal, and maternal outcomes: An Alabama population-based study

Purpose of Study It is important to identify possible changes in fetal, neonatal, and maternal outcomes in relation to the beginning of the COVID-19 pandemic using population-based data to inform strategies to mitigate the impact of the pandemic on adverse pregnancy outcomes. Objective To test the hypothesis that the COVID-19 pandemic was associated with a higher rate of stillbirth and a lower rate of neonatal mortality. Methods Used Design: This population-based cohort study compares two epochs: calendar weeks 9-52 (defined as week one starting on the first Sunday of the year) of the years 2016 to 2019 (baseline period)) and 2020 (pandemic period). Setting: Data from the Alabama Department of Public Health, Center for Health Statistics database of Alabama state residents who delivered in Alabama. Participants: All pregnant women with stillbirths ≥20 weeks and live births ≥22 weeks gestational age. Primary Outcomes: The stillbirth and neonatal mortality rate. Summary of Results Data on 237,625 pregnant women were included;46,816 were from the pandemic and 190,809 were from the baseline period. On bivariate analysis, the stillbirth rate did not differ (8.1 vs. 8.9/1000 births, p-value=0.104), but the neonatal mortality rate was lower (2.8 vs. 4.5/1000 live births, p-value<0.001), and the maternal mortality rate was higher (102.5 vs. 62.4/100,000 births, p-value=0.003) during the COVID-19 pandemic period as compared to the baseline period. On logistic regression analysis adjusting for socio-demographic variables (maternal race, age, education, and prenatal care), the pandemic period was associated with a decrease in stillbirth (OR=0.76, 95%CI=0.64, 0.91, pvalue= 0.002) and neonatal mortality rate (OR=0.62, 95% CI=0.51-0.75, p-value<0.001) but an increase in maternal mortality rate (OR=1.64, 95% CI=1.17-2.30, P-value=0.003) as compared to the baseline period. Conclusions The current population-based study shows that the COVID-19 pandemic period was associated with no change in the stillbirth rate, a lower neonatal mortality rate, and a higher maternal mortality rate compared to the baseline period.

The Impact of National Stereotypes towards Country-of-Origin Images on Purchase Intention: Empirical Evidence from Countries of the Belt and Road initiative

The purpose of this paper is to explore how the country-of-origin image mediates the effect of national stereotypes along two dimensions of perceived competence and warmth, on consumers' consumption behaviors, especially in today's environment, the capricious COVID-19 and the deepening and expanding "The Belt and Road" initiative. Research design, data, and methodology: After collecting 1500 primary data from twelve countries along the 21st - Century Maritime Silk Road, this paper conducts ANOVA and SEM in SPSS25.0 and AMOS 24.0 separately to analyze measurements, structural models, and hypotheses via using 1277 final samples. The mediation results illustrate the asymmetric dominance of the two dimensions of national stereotypes, indicating that the country-of-origin image shows the complementary mediation in the effect of perceived competence on purchase intention;whereas, the country-of-origin image holds the indirect-only mediation in the impact of perceived warmth on purchase intention. The results of the moderation show that the effect of country-of-origin image on purchase intention is more significant for consumers who perceive COVID-19 in China to be of lesser severity than those who believe it to be of higher severity. Eased on the paper's results, some implications for practice and theory are highlighted.

Temperature-Responsive Multilayer Films Based on Block Copolymer-Coated Silica Nanoparticles for Long-Term Release of Favipiravir

Using surface-initiated atom-transfer radical polymerization, temperature-responsive block polymers were functionalized on the surface of silica nanocapsules (SNCs) by a "grafting from" technique. Favipiravir, a potential medicine candidate for the treatment of coronavirus disease (COVID-19), was encapsulated in polymer-coated SNCs and further incorporated into welldefined films by layer-by-layer self-assembly. The multilayer films composed of polymer-coated SNCs and poly(methacrylic acid) (PMAA) homopolymers exhibited swelling/deswelling behaviors under the trigger of a temperature stimulus. For the first time, the impact of steric hindrance on the assembling behavior, swelling/ deswelling transition, and delivering capacity of nanocapsule-based multilayer films was investigated. SNCs with coronae of higher steric hindrance resulted in a larger layering distance during film growth. Moreover, the difference in the sustained release rates of the drug indicated their diverse diffusion coefficients and intermolecular interactions within the multilayer films, due to the presence of a methyl spacer at the amino group of nanocapsule coronae and weaker ionic pairing between SNC coronae and PMAA homopolymers. The profile of drug release from the films was dependent on the temperature value of the surrounding environment. At 37 and 40 degrees C, the films were able to efficiently entrap favipiravir, with as low as 50% released in 80 days, whereas a faster favipiravir release was triggered by exposure to a lower temperature value at 25 degrees C. This work demonstrates the first proof-of-concept platform of temperature-responsive SNC-incorporated multilayered films with a well-defined internal structure and a sustained release profile for on-demand in vitro drug delivery.

Research on Social Media Content Marketing: An Empirical Analysis Based on China’s 10 Metropolis for Korean Brands

Drawing from the Uses and Gratifications Theory (UGT), this study explores the influences of the gratifications derived from the use of the WeChat on Chinese consumers’ purchase intention for South Korean brands. A total of 2,276 respondents from ten cities in China—Beijing, Shanghai, Guangzhou, Shenzhen, Ji’nan, Nanjing, Zhengzhou, Wuhan, Chengdu, and Xi’an—were part of this study. Structural equation modeling (SEM) and PROCESS analysis was applied to examine the data. Gratifications that Chinese consumers receive from the WeChat, such as functional information, entertaining information, social interaction, brand interaction, and self-concept, positively influence their brand identity. In addition, the identity of South Korean brands positively correlated with consumer’s purchase intention in China. More importantly, by using a moderated mediation model, this research finds that the relationship between SNS (social networking service) content marketing and purchase intention is influenced by consumers’ regulatory focus and CSR performance of South Korean enterprises for COVID-19 in China. This study’s findings could extend the existing theoretical framework on applying the Uses and Gratifications Theory to social media. In addition, results are in line with those authors who suggest that local social media use may positively affect foreign brand promotion. Theoretical and practical implications are also discussed. © The Author(s) 2021.

Unveiling Potential Active Constituents and Pharmacological Mechanisms of Pudilanxiaoyan Oral Liquid for Anti-Coronavirus Pneumonia Using Network Pharmacology

The outbreak of novel coronavirus pneumonia (COVID-19), defined as a worldwide pandemic, has been a public health emergency of international concern. Pudilanxiaoyan oral liquid (PDL), an effective drug of Traditional Chinese Medicine (TCM), is considered to be an effective and alternative means for clinical prevention of COVID-19. The purpose of this study was to identify potential active constituents of PDL, and explore its underlying anti-COVID-19 mechanism using network pharmacology. Integration of target prediction (SwissTargetPrediction and STITCH database) was used to elucidate the active components of PDL. Protein-protein interaction network analyses, gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, network construction, and molecular docking were applied to analyze the prospective mechanisms of the predicted target genes. Our results showed that the key active ingredients in PDL were luteolin, apigenin, esculetin, chrysin, baicalein, oroxylin A, baicalin, wogonin, cymaroside, and gallic acid. A majority of the predicted targets were mainly involved in the pathways related to viral infection, lung injury, and inflammatory responses. An in vitro study further inferred that inhibiting the activity of nuclear factor (NF)-B signaling pathway was a key mechanism by which PDL exerted anti-COVID-19 effects. This study not only provides chemical basis and pharmacology of PDL but also the rationale for strategies to exploring future TCM for COVID-19 therapy.

Wellbeing and Healthcare: Exploring Ways of Interactive Prototyping with Mental Process

This study explores prototype design with psychology methods to guide students to apply their expertise to real product design. We research specific populations in COVID-19 in China and the impact of people's psychological changes on interactive behavior in different context. We transform mental processes such as cognition, emotion, and volition into interaction behaviors with psychological research methods, and then these behaviors are transformed into interaction prototype products. Two prototypes were built and experienced, i.e., CareforCarers and Presport We discuss these prototypes, experiences for initiating interaction design programs based on multidisciplinary education. This study demonstrates how to transform user behaviors, psychological insights, and user needs into interactive prototype designs. We found that integrating psychological elements improve product design's attribute on interaction quality through quick evaluation sessions. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

The heterogeneity research of the impact of epu on environmental pollution: Empirical evidence based on 15 countries

While economic growth has been the main goal of countries around the world, environmental problems such as air pollution have also arisen. Since the increase in economic uncertainty is limiting production capacity and consumers’ marginal propensity to consume, which reduces CO2 emissions, economic policy uncertainty has become one of the most important factors affecting CO2 emissions. COVID-19 has demonstrated that economic policy uncertainty reduces the enthusiasm of market participants, which, in turn, reduces energy demand and CO2 emissions. In order to further study the impact of economic policy uncertainty on air pollution, this study uses a panel model to empirically test the data for a sample of 15 countries covering the period from 1997 to 2019. According to the empirical results, we find that the economic policy uncertainty has a significant negative impact on per capita CO2 emissions. That is, the higher the uncertainty of economic policy, the lower the per capita CO2 emissions of countries. What’s more, this negative effect is larger in emerging market countries than in advanced countries. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

[Clinical features of 141 fatal cases of coronavirus disease in Jinyintan Hospital in Wuhan, China].

Objective: To describe the epidemiological characteristics and clinical features of patients with fatal coronavirus disease (COVID-19), in order to provide evidence for clinical diagnosis and treatment. Methods: In this retrospective study, we analyzed data on 141 fatal cases of confirmed COVID-19 that occurred among patients in Jinyintan Hospital in Wuhan, China, from January 20 to March 6, 2020. We analyzed their epidemiological characteristics, clinical and radiological features, laboratory results, and treatment. Results: Of the 141 patients (49 females, 92 males), the median age was 77 years (range: 24-92 years). The most likely source of exposure included the Huanan seafood market (n=3, 2%), family members (n=6, 4%), and hospital-acquired infection (n=8, 6%). The remaining 116 patients (72%) had no known source of exposure. Of the patients, 101 (72%) had chronic diseases. The most common comorbidities were hypertension, diabetes and coronary heart disease. The most common clinical manifestations were fever (n=121, 85%), dry cough (n=77, 54%), shortness of breath (n=23, 16%), and chest pain (n=15, 10%). Less common clinical manifestations included fatigue (n=7, 4%), headache (n=3, 2%), disorders of consciousness (n=2, 1%), diarrhea (n=2, 1%) and lumbago (n=1, 0.7%). In terms of laboratory tests, the absolute value of lymphocytes in most patients was reduced (n=132, 94%), but C-reactive protein (n=141, 100%), procalcitonin(n=121, 89%), serum amyloid (n=140, 99%) were significantly increased. The most common findings on imaging of the lungs were bilateral multiple mottling and ground-glass opacity (n=101, 72%), mainly in the lower lobes (n=15, 10%), with lesions being more common on the right. Other imaging findings included diffuse consolidation (n=4, 3%), ground-glass opacity and consolidation (n=20, 14%), and pneumothorax (n=1, 0.7%). All patients were treated with antibiotics and antiviral drugs. Other treatments included immunoglobulin (n=49, 35%), corticosteroids (n=45, 32%), continuous renal replacement therapy (n=24, 17%), and extracorporeal membrane oxygenation (n=12, 9%). All patients were treated with oxygen therapy. The mode of administration included invasive mechanical ventilation (n=61, 43%), noninvasive mechanical ventilation (n=65, 46%), and nasal catheter oxygen inhalation (n=15, 11%). The direct causes of death were acute respiratory distress syndrome (n=90, 64%), multiple organ failure (n=24, 17%), sudden cardiac arrest (n=11, 8%), viral myocarditis (n=8, 5%), acute myocardial infarction (n=4, 3%), cerebrovascular accident (n=3, 2%), and acute gastrointestinal bleeding (n=1, 0.7%). Conclusions: Risk factors for death due to COVID-19 included older age, male sex, and the presence of comorbidities. The most common direct causes of death were acute respiratory distress syndrome, multiple organ failure, sudden cardiac arrest, and viral myocarditis.

Clinical analysis of 17 cases of COVID-19 after operation

Objective: To explore the risk factors and control methods of surgical operation during the outbreak of coronavirus disease 2019 (COVID-19), and to summarize the experience of prevention and treatment methods of COVID-19 under surgical conditions from a single center during the epidemic. Methods: The clinical data of 17 patients diagnosed as COVID-19 postoperatively in Renmin Hospital of Wuhan University from January 3 to January 22, 2020 were collected and analyzed. The diseases were classified according to the Chinese Diagnosis and Treatment of Novel Coronavirus Infected Pneumonia (5th trial edition). The mild and moderate type patients were incorporated into the non-severe group, while the severe and critical ones were categerized into the severe group. Then we compared the general information, clinical symptoms, laboratory test results, and outcomes between the two groups. Results: The clinical data of 3 339 patients underwent surgical operation were reviewed, and 17 patients were diagnosed as COVID-19 after operation, with a 0.51% incidence rate. Among them, 7 cases (41.2%) were severe, and 2 cases (11.8%) died of respiratory failure. The clinical manifestations were mainly fever (76.47%) and cough (58.82%). Laboratory examination results showed that in most patients, the leukocyte count was normal (70.59%), lymphocyte count was lower (88.24%), and C-reactive protein level was higher (88.24%). Immune function tests showed that cellular immune function was significantly impaired in some patients. Among them, 62.5%, 62.5% and 75% of the patients had decreased CD3 count, CD4 count and CD8 count. The percentage of severe COVID-19 cases in open surgery patients was significantly higher than that in minimally invasive surgery ones (71.43% vs 20%, P=0.034). Conclusion: The proportion of severe cases and mortality in COVID-19 patients undergone surgery are higher than those who haven't;and the severity rate of them receiving open surgery is higher than those performed minimally invasive surgery. During the epidemic, elective or confine surgery should be postponed and the indications for emergency surgery should be strictly accorded with;If an emergency surgery is inevitable, minimally invasive surgery should be selected as a priority. Postoperative screening of COVID-19 should be strengthened, while early, detection, early reporting, early isolation and early treatment should be applied to the infected patients. © 2021, Editorial Board of Medical Journal of Wuhan University. All right reserved.