[Performance of screening of contacts of COVID-19 cases in same flight].

Objective: To understand the performance of 2019-nCoV nucleic acid detection in screening of contacts of COVID-19 cases in same flights and provide evidence for the effective screening of persons at high risk for the infection in domestic flights. Methods: The information of passengers who took same domestic flights with COVID-19 cases in China from April 1, 2020 to April 30, 2022 were retrospectively collected,and χ2 test was used to analyze positive nucleic acid detection rates in the passengers in different times before the onsets of the index cases, in different seat rows and in epidemic periods of different 2019-nCoV variants. Results: During the study period, a total of 433 index cases were identified among 23 548 passengers in 370 flights. Subsequently, 72 positive cases of 2019-nCoV nucleic acid were detected in the passengers, in whom 57 were accompanying persons of the index cases. Further analysis of the another 15 passengers who tested positive for the nucleic acid showed that 86.67% of them had onsets or positive detections within 3 days after the diagnosis of the index cases, and the boarding times were all within 4 days before the onsets of the index cases. The positive detection rate in the passengers who seated in first three rows before and after the index cases was 0.15% (95%CI: 0.08%-0.27%), significantly higher than in the passengers in other rows (0.04%, 95%CI: 0.02%-0.10%, P=0.007),and there was no significant difference in the positive detection rate among the passengers in each of the 3 rows before and after the index cases (P=0.577). No significant differences were found in the positive detection rate in the passengers, except the accompanying persons, among the epidemics caused by different 2019-nCoV variants (P=0.565). During the Omicron epidemic period, all the positive detections in the passengers, except the accompanying persons, were within 3 days before the onset of the index cases. Conclusions: The screening test of 2019-nCoV nucleic acid can be conducted in the passengers took the same flights within 4 days before the onsets of the index cases on board. Passengers who seated within 3 rows from the index cases can considered as the close contacts at high risk for 2019-nCoV, for whom screening should be conducted first and special managements are needed. The passengers in other rows can be classified as general risk persons for screening and management.

[Latent period and incubation period with associated factors of COVID-19 caused by Omicron variant].

Objective: To estimate the latent period and incubation period of Omicron variant infections and analyze associated factors. Methods: From January 1 to June 30, 2022, 467 infections and 335 symptomatic infections in five local Omicron variant outbreaks in China were selected as the study subjects. The latent period and incubation period were estimated by using log-normal distribution and gamma distribution models, and the associated factors were analyzed by using the accelerated failure time model (AFT). Results: The median (Q1, Q3) age of 467 Omicron infections including 253 males (54.18%) was 26 (20, 39) years old. There were 132 asymptomatic infections (28.27%) and 335 (71.73%) symptomatic infections. The mean latent period of 467 Omicron infections was 2.65 (95%CI: 2.53-2.78) days, and 98% of infections were positive for nucleic acid test within 6.37 (95%CI: 5.86-6.82) days after infection. The mean incubation period of 335 symptomatic infections was 3.40 (95%CI: 3.25-3.57) days, and 97% of them developed clinical symptoms within 6.80 (95%CI: 6.34-7.22) days after infection. The results of the AFT model analysis showed that compared with the group aged 18-49 years old, the latent period [exp(ß)=1.36 (95%CI: 1.16-1.60), P<0.001] and incubation period [exp(ß)=1.24 (95%CI: 1.07-1.45), P=0.006] of infections aged 0-17 years old were prolonged. The latent period [exp(ß)=1.38 (95%CI: 1.17-1.63), P<0.001] and the incubation period [exp(ß)=1.26 (95%CI: 1.06-1.48), P=0.007] of infections aged 50 years old and above were also prolonged. Conclusion: The latent period and incubation period of most Omicron infections are within 7 days, and age may be a influencing factor of the latent period and incubation period.

The nutrition management of patients with Coronavirus disease 2019 in the hospital: An expert opinion (2020).

To prevent coronavirus disease 2019 (COVID-19) and enhance the nutrition management for patients, the Beijing Quality Control and Improvement Center for Clinical Nutrition Therapy organized relevant experts to formulate "The Nutrition Management of Patients with Coronavirus Disease 2019 in the Hospital: An Expert Opinion (2020)". It clearly stated that food safety, food hygiene, and nutrition management should be incorporated into the whole process of prevention, control, treatment, and rehabilitation of COVID-19. The reasonable and standardized pathway of nutrition management, which includes nutrition-risk screening, malnutrition diagnosis, nutritional support therapy and nutrition monitoring, should be established to improve the immune status, clinical outcome, and quality of life of patients with COVID-19.Copyright © 2021, Peking Union Medical College Hospital. All rights reserved.

Double-Network Protein Hydrogels as Flexible Pressure Sensors for Contactless Delivery

To meet the growing demand for sustainable development and ecofriendliness, hydrogels based on biopolymers have attracted widespread attention for developing flexible pressure sensors. Natural globular proteins exhibit great potential for developing biobased pressure sensors owing to their advantages of high water solubility, easy gelation, biocompatibility, and low production cost. However, realizing globular protein hydrogel-based sensors with interfacial and bulk toughness for pressure sensing and use in wearable devices remains a challenge. This study focuses on developing a high-performance flexible pressure sensor based on a biobased protein hydrogel. Consequently, a flexible protein/polyacrylamide (PAM) hydrogel with a featured double-network (DN) structure linked covalently with hydrogen bonds was first synthesized via a one-pot method based on natural ovalbumin (OVA). The unique DN structure of the as-synthesized OVA/PAM hydrogel affords excellent mechanical performance, flexibility, and adhesion properties. The mechanical properties of the DN hydrogel were enhanced after further cross-linking with Fe3+ and treatment with glycerol. Subsequently, the flexible pressure sensor was constructed by sandwiching a microstructured OVA/PAM dielectric layer between two flexible silver nanowire electrodes. The obtained sensor exhibits a high sensitivity of 2.9 kPa-1 and a short response time of 18 ms, ensuring the ability to monitor physiological signals. Based on its excellent performance, the fabricated sensor was used for monitoring the signals obtained using practical applications such as wrist bending, finger knocking, stretching, international Morse code, and pressure distribution. Particularly, we implemented a contactless delivery system using the fabricated OVA-based pressure sensors linked to unmanned vehicles and global positioning systems, providing a solution for low-risk commodity distribution during Coronavirus disease 2019 (COVID-19).

High-Performance Flexible Humidity Sensor Based on MoOX Nanoparticle Films for Monitoring Human Respiration and Non-Contact Sensing

Flexible humidity sensors with high sensitivity, fast response time, and outstanding reliability have the potential to revolutionize electronic skin, healthcare, and non-contact sensing. In this study, we employed a straightforward nanocluster deposition technique to fabricate a resistive humidity sensor on a flexible substrate, using molybdenum oxide nanoparticles (MoOx NPs). We systematically evaluated the humidity-sensing behaviors of the MoOx NP film-based sensor and found that it exhibited exceptional sensing capabilities. Specifically, the sensor demonstrated high sensitivity (18.2 near zero humidity), a fast response/recovery time (1.7/2.2 s), and a wide relative humidity (RH) detection range (0-95%). The MoOx NP film, with its closely spaced granular nanostructure and high NP packing density, exhibited insensitivity to mechanical deformation, small hysteresis, good repeatability, and excellent stability. We also observed that the device exhibited distinct sensing kinetics in the range of high and low RH. Specifically, for RH > 43%, the response time showed a linear prolongation with increased RH. This behavior was attributed to two factors: the higher physical adsorption energy of H2O molecules and a multilayer physical adsorption process. In terms of applications, our sensor can be easily attached to a mask and has the potential to monitor human respiration owing to its high sensing performance. Additionally, the sensor was capable of dynamically tracking RH changes surrounding human skin, enabling a non-contact sensing capability. More significantly, we tested an integrated sensor array for its ability to detect moisture distribution in the external environment, demonstrating the potential of our sensor for contactless human-machine interaction. We believe that this innovation is particularly valuable during the COVID-19 epidemic, where cross-infection may be averted by the extensive use of contactless sensing. Overall, our findings demonstrate the tremendous potential of MoOx NP-based humidity sensors for a variety of applications, including healthcare, electronic skin, and non-contact sensing.

Robotization and labour demand in post-pandemic era: Microeconomic evidence from China

We study how robotization, namely the "machine substitution” policy, impacts firms' labour demand in the post pandemic era. Using a unique firm-level data set of online job postings in Dongguan, known as "The World Factory” in China, we find that "machine substitution” policy fosters the funded firms to expand their labour demand. The expansion is mainly driven by the growing demand for manufacturing workers, which offsets the reduced demand for service workers. Also, the expansion can be attributed to an increase in the number of employees listed in job postings rather than an increase in position types. Further analysis suggests that this positive impact is mainly attributable to the productivity effect rather than the restatement effect. Furthermore, there is no evidence of heterogeneity by sector or firm size but the effect of the policy varies by regional epidemic severity. Our results not only reveal the labour demand in the Covid-19 but also provide prominent implications for occupational security and steady economic growth. © 2023 Elsevier Inc.

Case report of congenital disorder of glycosylation type Ia combined with dilated cardiomyopathy.

Clinical data and follow-up of a case of congenital disorder of glycosylation type Ia (CDG-Ia) combined with dilated cardiomyopathy admitted to the Department of Cardiology, Children's Hospital of Nanjing Medical University were analyzed retrospectively.The 5-year-old female patient was admitted in December 2016 due to recu-rrent shortness of breath for 2 months.Clinical symptoms and signs included repeated attacks of shortness of breath, physical retardation, malnutrition, binocular esotropia, multiple episodes of hypoglycemia, hepatosplenomegaly, hypotonia and other multi-system damages.Cardiac echocardiography suggested the feature of dilated cardiomyopathy, including the significant enlargement of the left ventricle, and decreased systolic function.Genetic testing revealed a compound heterozygous mutation in the PMM2 gene, and as a result, the patient was diagnosed as CDG-Ia.The patient's condition improved after symptomatic treatments such as Cedilanid, Dopamine, Dobutamine, Furosemide, as well as support treatments like myocardium nutrition, blood sugar maintenance, liver protection, etc.After discharge, the patient was given oral Digoxin, Betaloc, Captopril and diuretics, and hypoglycemia-controlling agents.The patient was followed up every 3-6 months.After more than 2 years of follow-up, the heart function and heart enlargement gradually returned to normal.During the Corona Virus Disease 2019 outbreak, self-withdrawal continued for 2 months.Re-examinations showed decreased cardiac function and enlarged left ventricle again.Medications were resumed again, and the patient was followed up closely.This case report suggested that CDG-Ia may be associated with dilated cardiomyopathy, and the cardiac phenotype may be improved by symptomatic supportive treatment.Copyright © 2021 by the Chinese Medical Association.

Double-Network Protein Hydrogels as Flexible Pressure Sensors for Contactless Delivery

To meet the growing demand for sustainable development and ecofriendliness, hydrogels based on biopolymers have attracted widespread attention for developing flexible pressure sensors. Natural globular proteins exhibit great potential for developing biobased pressure sensors owing to their advantages of high water solubility, easy gelation, biocompatibility, and low production cost. However, realizing globular protein hydrogel-based sensors with interfacial and bulk toughness for pressure sensing and use in wearable devices remains a challenge. This study focuses on developing a high-performance flexible pressure sensor based on a biobased protein hydrogel. Consequently, a flexible protein/polyacrylamide (PAM) hydrogel with a featured double-network (DN) structure linked covalently with hydrogen bonds was first synthesized via a one-pot method based on natural ovalbumin (OVA). The unique DN structure of the as-synthesized OVA/PAM hydrogel affords excellent mechanical performance, flexibility, and adhesion properties. The mechanical properties of the DN hydrogel were enhanced after further cross-linking with Fe3+ and treatment with glycerol. Subsequently, the flexible pressure sensor was constructed by sandwiching a microstructured OVA/PAM dielectric layer between two flexible silver nanowire electrodes. The obtained sensor exhibits a high sensitivity of 2.9 kPa-1 and a short response time of 18 ms, ensuring the ability to monitor physiological signals. Based on its excellent performance, the fabricated sensor was used for monitoring the signals obtained using practical applications such as wrist bending, finger knocking, stretching, international Morse code, and pressure distribution. Particularly, we implemented a contactless delivery system using the fabricated OVA-based pressure sensors linked to unmanned vehicles and global positioning systems, providing a solution for low-risk commodity distribution during Coronavirus disease 2019 (COVID-19). © 2023 American Chemical Society.

A Dynamic Access Control Model Based on Attributes and Intro VAE

Affected by the COVID-19 pandemic, teleworking is becoming more popular, with the exposed attack surface of the internal network expanding. Once outsiders personate accounts or insiders conduct illegal operations, the data security in teleworking with traditional border protection will be broken. Therefore, it is necessary to implement fine-grained and dynamic access control to protect data from malicious access. Attribute-based access control (ABAC) is ideal, where authorization is performed through attributes and rules. On this basis, risk assessment, context awareness, and machine learning are supplemented for dynamic access control. However, these methods have their limitations due to the requirement of sufficient prior knowledge and massive label-classified data. Moreover, it is challenging to obtain the samples of attack behaviors, and the attack behaviors may change frequently to evade detection. In contrast, the normal behaviors are relatively stable except for the update of network services. We propose a dynamic access control model, ABAC-IntroVAE, to address the above issues. ABAC-IntroVAE judges users' requests through rule matching and behavior analysis based on the attributes of the requests. It first filters out requests against the rules by rule matching. Then, the introspective variational autoencoder (IntroVAE) is used for behavior analysis to realize dynamic access decisions. Requests classified as normal can be authorized for access. ABAC-IntroVAE only needs samples of normal requests for training, avoiding the difficult task of collecting massive and frequently changing samples of attack requests. Meanwhile, the IntroVAE model is updated through continual learning to adapt to new-style normal behaviors due to the update of network services. Our experiment study suggests that our proposed ABAC-IntroVAE can effectively perform dynamic access control. It achieves an accuracy of 97.2% in abnormal detection and maintains an accuracy of over 97% through continual learning, despite the addition of new-style user behavior patterns. © 2022 IEEE.

Reasons for not improving visual acuity of DME patients due to interruption of anti-VEGF therapy during the pandemic and OCT imaging analysis

*AIM: To identify the reasons for not improving visual acuity of patients with diabetic macular edema (DME) and its correlation with optical coherent tomography (OCT) imaging characteristics. They were treated with anti - vascular endothelial growth factor (VEGF) again after an interruption of treatment due to the COVID - 19 pandemic. * METHODS: Retrospective cases study. A total of 31 patients (40 eyes) with DME and treated with anti-VEGF drugs in the Department of Ophthalmology of the First Affiliated Hospital of Xi' an Jiaotong University between December 2019 and July 2020 were selected. All patients had an treatment history of interruption due to COVID-19. Based on the behavioral standard of best corrected visual acuity (BCVA) at 1mo after re - treatment, they were divided into improved visual acuity group (14 eyes) and non-improved visual acuity group (26 eyes). All patients received comprehensive ophthalmic examinations, including BCVA, intraocular pressure, OCT, fundus photography, and fundus fluorescein angiography (FFA). The central retinal thickness (CRT), hyper - reflective retinal dots (HRD), subretinal fluid (SRF), intraretinal fluid (IRF), disorganization of the inner retinal layers (DRIL) and ellipsoid zone disruption (EZD) were quantified by Image J. The correlation between BCVA and CRT, the number of HRD, the diameter of SRF and IRF, and the height of DRIL and EDZ width at 1mo after treatment were analyzed by Spearman correlation. * RESULTS: The proportion of HRD in OCT was significantly higher in the non - improved visual acuity group than that in the improved visual acuity group (chi2 = 5.43, P = 0.0072);There was a positive correlation between the difference of BCVA (LogMAR) and CRT change in DME patients after treatment (rs = 0.406, P = 0.009);There was a positive correlation between BCVA (LogMAR) and EZD width after treatment (rs = 0.358, P = 0.023). There was no correlation between BCVA (LogMAR) after treatment and the number of CRT (rs = - 0. 086, P = 0. 600) and HRD (rs = - 0. 115, P = 0. 482), the diameter and height of SRF (rs = 0.102, P = 0.530;rs = 0.100,P = 0.538) and IRF (rs = 0.134, P = 0. 410;rs = - 0. 014, P = 0. 932), and the width of DRIL (rs = 0.089, P = 0.587). * CONCLUSION(S): The probability of retinal HRD was significantly higher in patients with no visual improvement than that in patients with visual improvement after the re - treatment with anti - VEGF due to the treatment interruption during COVID- 19. EZD width was also closely correlated to the prognosis of visual acuity. As for these patients, HRD manifestations in OCT should be comprehensively considered, taking intravitreal injection of glucocorticoid as an auxiliary strategy if necessary. Copyright © 2022 International Journal of Ophthalmology (c/o Editorial Office). All rights reserved.

Lipid nanoparticles for cardiac RNA delivery

Introduction: RNA-based therapies of the myocardium offer a range of therapeutic opportunities for conditions in which gene transfer needs to be highly effective but transient, such as cardiac regeneration and cardiac gene editing. MicroRNA and mRNA gene transfer can be achieved by intramyocardial injection of lipofectamine-based products, but these are not amenable to clinical translation. In contrast, lipid nanoparticles (LNPs) have already reached clinical approval for siRNA administration with patisiran in 2018 and for mRNA delivery with the COVID-19 vaccines by Pfizer-BioNTech and Moderna in 2020. Objective(s): We wanted to develop Stable Nucleic Acid Lipid nanoParticles (SNALPs) for the effective myocardial delivery of microRNAs and mRNAs. Material(s) and Method(s): We generated various SNALP formulations via ethanol injection method, carrying the pro-regenerative microRNA-199a-3p or GFP mRNA and assessed their transfection efficiency by high-content microscopy (stimulation of EdU incorporation and GFP fluorescence respectively) in neonatal rat and mouse cardiomyocytes and upon intramyocardial injection in mice. Result(s): We started by investigating the inclusion of different ionisable lipids, helper lipids and PEG-lipids in the nanoparticle shell. Then, we systematically tested the effect of varying the molar ratios of each of the constituents to improve transfection. After optimising the formulations in vitro, we tested the same in mice through direct intramyocardial injection. Conclusion(s): The results obtained highlight the applicability of the LNP technology for efficient delivery of mRNA and microRNA into cardiomyocytes. Copyright © 2022

Moxibustion for COVID-19: a systematic scoping review

Moxibustion has been widely used in the prevention and treatment of COVID-19. However, there is no systematic review of current topics and clinical findings on moxibustion for COVID-19. We conducted this scoping review to systematically summarize and analyze the themes and findings of published articles, and to provide an overview of current knowledge and practice of moxibustion for COVID-19.Methods:: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, SinoMed, Wan Fang Data, and VIP databases were searched from inception until April 2022. The relevant data were presented through bar graphs, structured tables, and figures along with descriptive statistics and analysis. This scoping review was conducted based on the PRISMA-ScR Checklist. Results:: A total of 76 articles were reviewed: 47 reviews, 19 clinical research studies, seven systematic reviews (all were protocols), and three guidelines. All the studies were conducted by Chinese researchers and published from January 1, 2020 to March 14, 2022. The feasibility of moxibustion in the prevention and treatment of mild or moderate COVID-19 is based on the consensus of therapeutic mechanisms and effectiveness. The most adopted approach was the suspended and gentle moxibustion, and the most frequently applied or recommended acupoints were found to be ST36, CV8, CV6, CV4, CV12, GV14, BL13, LI4, ST25, and LR3. Conclusions:: As a convenient and safe traditional Chinese medicine (TCM) therapy with its specific feature, moxibustion has been significantly effective at ameliorating mild or moderate symptoms among COVID-19 patients. Further large-scale, well-designed research and international cooperation are still warranted in clinical evaluations of moxibustion. Graphical :: http://links.lww.com/AHM/A35.

Application of Uncertain AHP Method in Analyzing Travel Time Belief Reliability in Transportation Network

Because predictions of transportation system reliability can provide useful information for intelligent transportation systems (ITS), evaluation of them might be viewed as a beneficial activity for reducing traffic congestion. This evaluation procedure could include some alternatives and criteria in a discrete decision space. To handle this evaluation process in an uncertain environment, a novel uncertain multi-criteria decision-making (MCDM) method is put forward in this paper. Considering the validity of uncertainty theory as a measure of epistemic uncertainty, we first introduce it into analytic hierarchy process (AHP) and provide the whole calculation procedure of the approach. The proposed approach is employed to evaluate regional travel time belief reliability in a case study. Additionally, a comparison is performed between the results of uncertain AHP and other MCDM methods to examine the efficiency of this method. These analyses show that uncertainty theory is particularly suited to be employed combination with the AHP method.

[The differential diagnosis of pulmonary infiltrates in cancer patients during the outbreak of the 2019 novel coronavirus disease].

Objective: To investigate the principles of differential diagnosis of pulmonary infiltrates in cancer patients during the outbreak of novel coronavirus (2019-nCoV) by analyzing one case of lymphoma who presented pulmonary ground-glass opacities (GGO) after courses of chemotherapy. Methods: Baseline demographics and clinicopathological data of eligible patients were retrieved from medical records. Information of clinical manifestations, history of epidemiology, lab tests and chest CT scan images of visiting patients from February 13 to February 28 were collected. Literatures about pulmonary infiltrates in cancer patients were searched from databases including PUBMED, EMBASE and CNKI. Results: Among the 139 cancer patients who underwent chest CT scans before chemotherapy, pulmonary infiltrates were identified in eight patients (5.8%), five of whom were characterized with GGOs in lungs. 2019-nCoV nuclear acid testing was performed in three patients and the results were negative. One case was a 66-year-old man who was diagnosed with non-Hodgkin lymphoma and underwent CHOP chemotherapy regimen. His chest CT scan image displayed multiple GGOs in lungs and the complete blood count showed decreased lymphocytes. This patient denied any contact with confirmed/suspected cases of 2019-nCoV infection, fever or other respiratory symptoms. Considering the negative result of nuclear acid testing, this patient was presumptively diagnosed with viral pneumonia and an experiential anti-infection treatment had been prescribed for him. Conclusions: The 2019 novel coronavirus disease (COVID-19) complicates the clinical scenario of pulmonary infiltrates in cancer patients. The epidemic history, clinical manifestation, CT scan image and lab test should be taken into combined consideration. The 2019-nCoV nuclear acid testing might be applied in more selected patients. Active anti-infection treatment and surveillance of patient condition should be initiated if infectious disease is considered.

Single stock trading with deep reinforcement learning: A comparative study

In this paper, we apply Deep Reinforcement Learning (DRL) methods to automate the trading of single stock. The A2C, PPO, DDPG, TD3 and SAC deep reinforcement learning models are built and studied comparatively. Shanghai Composite Index (SH00001) is used as the trading stock, where the stock data before the Covid-19 is used as the training set, and the data after the Covid-19 is used as the testing (trading) set to back-test the performance of these models. Experimental results show that the DDPG, TD3, and SAC models outperform the benchmark, among which the DDPG model shows the most obvious advantages in returns and risk control, achieving a cumulative return rate of 25%, while the TD3 and SAC models achieve a cumulative return rate of 16-17%. The A2C and PPO models have inferior performance comparing to the benchmark. © 2022 ACM.

A management method of chronic diseases in the elderly based on IoT security environment

Due to the global influenza pandemic and the increasing health problems of the elderly, healthcare for the elderly has become an important application of Internet of Things(IoT) technology. However, under the condition of smart healthcare, the privacy of the elderly is not well protected. Therefore, to ensure the information security of the elderly, this paper proposes a management method for elderly chronic diseases based on the IoT security environment, establishes a security protection mechanism, and uses the IoT technology to monitor the vital signs of the elderly in real-time. At the same time, the Disease Immune Rehabilitation Algorithm (DIRA) is constructed based on the physiological data collected by the device to identify healthy people and reduce the number of infected people. Through experiments on several generations, the results show that this method can increase the proportion of the immune population to a certain extent and reduce the number of infected people.

Evaluation of Long-Term Modeling Fine Particulate Matter and Ozone in China During 2013-2019

Air quality in China has been undergoing significant changes due to the implementation of extensive emission control measures since 2013. Many observational and modeling studies investigated the formation mechanisms of fine particulate matter (PM2.5) and ozone (O-3) pollution in the major regions of China. To improve understanding of the driving forces for the changes in PM2.5 and O-3 in China, a nationwide air quality modeling study was conducted from 2013 to 2019 using the Weather Research and Forecasting/Community Multiscale Air Quality (WRF/CMAQ) modeling system. In this study, the model predictions were evaluated using the observation data for the key pollutants including O-3, sulfur dioxide (SO2), nitrogen dioxide (NO2), and PM2.5 and its major components. The evaluation mainly focused on five major regions, that is , the North China Plain (NCP), the Yangtze River Delta (YRD), the Pearl River Delta (PRD), the Chengyu Basin (CY), and the Fenwei Plain (FW). The CMAQ model successfully reproduced the air pollutants in all the regions with model performance indices meeting the suggested benchmarks. However, over-prediction of PM2.5 was noted in CY. NO2, O-3,O- and PM2.5 were well simulated in the north compared to the south. Nitrate (NO3-) and ammonium (NH4+) were the most important PM2.5 components in heavily polluted regions. For the performance on different pollution levels, the model generally over-predicted the clean days but underpredicted the polluted days. O-3 was found increasing each year, while other pollutants gradually reduced during 2013-2019 across the five regions. In all of the regions except PRD (all seasons) and YRD (spring and summer), the correlations between PM2.5 and O-3 were negative during all four seasons. Low-to-medium correlations were noted between the simulated PM2.5 and NO2, while strong and positive correlations were established between PM2.5 and SO2 during all four seasons across the five regions. This study validates the ability of the CMAQ model in simulating air pollution in China over a long period and provides insights for designing effective emission control strategies across China.

Classification network of COVID-19 based on multi-modality fusion network

Since 2019, COVID-19 has been a major problem for the world's population. COVID-19 is known for its fast transmission and strong infection. Therefore, how to reduce the burden of medical system is becoming a hot topic in current research. Previous researchers have used deep learning techniques to effectively classify COVID-19. Although the results are remarkable, the input method (X-ray images) is simple. Therefore, a new multi-modality fusion network is proposed in this paper. In this network, the spatial and structural feature information in the image were highlighted by means of thermal map. Experiments show the effectiveness of the proposed network. © 2021 IEEE.

Domain-Specific Pretraining for Vertical Search: Case Study on Biomedical Literature

Information overload is a prevalent challenge in many high-value domains. A prominent case in point is the explosion of the biomedical literature on COVID-19, which swelled to hundreds of thousands of papers in a matter of months. In general, biomedical literature expands by two papers every minute, totalling over a million new papers every year. Search in the biomedical realm, and many other vertical domains is challenging due to the scarcity of direct supervision from click logs. Self-supervised learning has emerged as a promising direction to overcome the annotation bottleneck. We propose a general approach for vertical search based on domain-specific pretraining and present a case study for the biomedical domain. Despite being substantially simpler and not using any relevance labels for training or development, our method performs comparably or better than the best systems in the official TREC-COVID evaluation, a COVID-related biomedical search competition. Using distributed computing in modern cloud infrastructure, our system can scale to tens of millions of articles on PubMed and has been deployed as Microsoft Biomedical Search, a new search experience for biomedical literature: https://aka.ms/biomedsearch.

[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.