University Image Building via We Chat During the Covid-19 Pandemic: A Case Study of a Chinese Higher Education Institution

The contagious nature of the Covid-19 coronavirus has seriously challenged universities all over the world, as millions of students have been unable to attend classes on campus. For universities such as BNU-HKBU United International College (UIC), given the loss of face-to-face communication channels, social media such as UIC WeChat Account have been playing an important role in connecting students, parents and the university, and in displaying the university's image. The shift toward the use of social media during the Covid-19 pandemic has drawn our attention to the fact that most scholarly discussion of university image building has been from the perspective of tertiary institution management, while little attention has been given to the multimodal resources employed in WeChat posts during the image building process. This study thus focuses on an investigation, from a multimodal perspective, of image building of UIC, a higher education institution with English as the medium of instruction in China, during the Covid-19 pandemic. The study was conducted by drawing on the theoretical framework of the Corporate Identity system (CIS) which includes the Mind Identity System (MIS), Behavior Identity System (BIS) and Visual Identity System (VIS). From a bottom-up approach, in the first place, posts published by UIC from the outbreak of the pandemic were collected to build a small corpus. Then texts and pictures were categorized and analyzed to find out how different components and modes work together to form the BIS and VIS, and what MIS of UIC has been demonstrated. The study shows how multimodal resources on social media have supported the development of a university image in a time of crisis and social distancing. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021.

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.

Changes of knowledge attitude and practice in different stages of the COVID-19 epidemic among college students in Shanghai

Objective To investigate and compare the changes and associated factors of knowledge attitude and practice of college students in Shanghai between the early 2020 and the end of 2021 stages of the COVID-19 epidemic and analyze the influencing factors so as to provide reference for epidemic prevention and health education of college students. Methods A retrospective cross-sectional survey was conducted among 913 college students in 12 colleges and universities in Shanghai in 2021 from November to December with a self-designed questionnaire by multi-stage stratified cluster sampling so as to investigate the changes of college students, health literacy related to COVID-19 and the changes of knowledge attitude and practice between the early 2020 and the end of 2021 stages of the COVID-19 epidemic. Results In the early stage of the epidemic the average score of understanding of epidemic prevention and control policies was 2.93±0.94 information judgment was 3.10±0.89 satisfaction degree was 4.11± 1.09 cooperation degree was 4.31±0.96 communication intention was 3.91±1.15. By the end of 2021 the understanding of prevention and control policies was 2.95±0.98 Information judgment was 3.77±0.94 satisfaction degree was 4.22±1.10 cooperation degree was 4.36±0.99 communication intention was 3.97±1.20 there were significant changes at different stages P<0.01. The results of binary Logistic regression showed that majors of social sciences OR = 0.62 majors of natural sciences OR = 0.62 self-rated good health OR = 0.62 and self-rated relatively good health OR = 0.28 were negatively correlated with college students, cognition and attitude changes to the COVID-19 epidemic P<0.05 while the choice of "relatively consistent" OR = 3.31 in "change in health behavior according to reasonable health information" was positively correlated with knowledge and attitude changes P<0.05. Shanghai college students, health literacy about epidemic prevention was generally high. 79.4% of them had a "relatively high" score >80 and 82.6% of the students rated themselves "very well" and "relatively well" knew epidemic prevention. Conclusion Relatively high level of health literacy on epidemic prevention is observed among college students in Shanghai. There had been significant changes in their knowledge attitude and practice of the epidemic since the early stage. It is necessary to carry out more accurate and effective health education and dissemination according to different characteristics so as to build the prevention and control barrier of epidemic among college students. © 2022 by the Author(s).

Transmission risk of asymptomatic SARS-CoV-2 infection: a systematic review and meta-analysis

Background: Global evidence on the transmission of asymptomatic SARS-CoV-2 infection needs to be synthesized. Methods: A search of 4 electronic databases (PubMed, EMBASE, Cochrane Library, and Web of Science databases) as of January 24, 2021 was performed. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Studies which reported the transmission rate among close contacts with asymptomatic SARS-CoV-2 cases were included, and transmission activities occurred were considered. The transmission rates were pooled by zero-inflated beta distribution. The risk ratios (RRs) were calculated using random-effects models. Results: Of 4923 records retrieved and reviewed, 15 studies including 3917 close contacts with asymptomatic indexes were eligible. The pooled transmission rates were 1.79 per 100 person-days (or 1.79%, 95% confidence interval [CI] 0.41%–3.16%) by asymptomatic index, which is significantly lower than by presymptomatic (5.02%, 95% CI 2.37%–7.66%;p<0.001), and by symptomatic (5.27%, 95% CI 2.40%–8.15%;p<0.001). Subgroup analyses showed that the household transmission rate of asymptomatic index was (4.22%, 95% CI 0.91%–7.52%), four times significantly higher than non-household transmission (1.03%, 95% CI 0.73%–1.33%;p=0.03), and the asymptomatic transmission rate in China (1.82%, 95% CI 0.11%–3.53%) was lower than in other countries (2.22%, 95% CI 0.67%–3.77%;p=0.01). Conclusions: People with asymptomatic SARS-CoV-2 infection are at risk of transmitting the virus to their close contacts, particularly in household settings. The transmission potential of asymptomatic infection is lower than symptomatic and presymptomatic infections. This meta-analysis provides evidence for predicting the epidemic trend and promulgating vaccination and other control measures. Registered with PROSPERO International Prospective Register of Systematic Reviews, CRD42021269446;https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=269446. © 2022 The Author(s)

Assessment of residual chlorine in soil microbial community using metagenomics

Chlorine-containing disinfectants have been widely used around the world for the prevention and control of the COVID-19 pandemic. However, at present, little is known about the impact of residual chlorine on the soil micro-ecological environment. Herein, we treated an experimental soil-plant-microbiome microcosm system by continuous irrigation with a low concentration of chlorine-containing water, and then analyzed the influence on the soil microbial community using metagenomics. After 14-d continuous chlorine treatment, there were no significant lasting effect on soil microbial community diversity and composition either in the rhizosphere or in bulk soil. Although metabolic functions of the rhizosphere microbial community were affected slightly by continuous chlorine treatment, it recovered to the original status. The abundance of several resistance genes changed by 7 d and recovered by 14 d. According to our results, the chlorine residue resulting from daily disinfection may present a slight long-term effect on plant growth (shoot length and fresh weight) and soil micro-ecology. In general, our study assisted with environmental risk assessments relating to the application ofchlorine-containing disinfectants and minimization of risks to the environment during disease control, such as COVID-19. © 2022, Higher Education Press.

Various pathogen-laden aerosol deposition in the realistic human airway during inhalation

Studying the deposition of different pathogens with various sizes and shapes is vital for understanding various respiratory infectious diseases. Few studies focus on the deposition of pathogen-laden aerosol during inhalation, especially for different respiratory infectious pathogens. This paper studied the depositions of H3N2, SAR-CoV-2, Ebola virus, Escherichia coli, and different sizes of droplets in the realistic human respiratory airway during inhalation. And results show that large droplets are mainly deposited in the upper respiratory tract, while most of the small particles, especially viruses, will transmit to somewhere further than bronchi-G7 and be deposited into the deep lobes of the lungs. Over 90% of single virus particles will inhale into lobes. The deposition efficiency of pathogens in the right lobes is significantly higher than that in the left, and this phenomenon is more obvious in the superior lobes, which may also explain why lung carcinomas are more likely to develop in the right lung. Compared with other viruses, SARS-CoV-2 is more inhaled into the right superior lobe, which should be paid attention to. This paper may help learn about various respiratory infectious diseases and provide references for treatment methods and drug delivery locations. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/)

MSCs-exosomes in regeneration medicine: Current evidence and future perspectives

Exosomes, especially from mesenchymal stem cells, have attracted extensive attention in regeneration medicine. Mesenchymal stem cells derived exosomes (MSCs-exosomes) have shown anti-inflammatory, anti-oxidant, antiapoptosis and tissue regeneration effects in a variety of tissue injury repair models. MSCs-exosomes hold many excellent properties such as low immunogenicity, biocompatibility, and targeting capability. With the in-depth study on the generation and function of exosomes, MSCs-exosomes are considered to be the bright stars in the field of regenerative medicine. However, there are still many obstacles to overcome in terms of exosomes isolation, clinical trials and safety evaluation. In this article, what we should focus on about MSCs-exosomes in regeneration medicine will be discussed. Copyright © 2022 Centro Regional de Invest. Cientif. y Tecn.. All rights reserved.

Transportation System Operating Characteristics Analysis of Beijing during COVID-19

Traffic operation has shown abnormal characteristics during COVID-19. This paper obtains traffic data from multiple fields in Beijing for the whole year of 2020, combines traffic operation data with the number of confirmed cases, and deeply explores the operating characteristics of road networks, public transportation, and intercity transportation at various stages during the major epidemic. The results showed that travel demand decreased significantly during the epidemic period. From the perspective of urban road network traffic pressure, the demand for rigid travel in peak hours during the epidemic recovery period is relatively large. Based on this research, it can provide decision support for the government to formulate relevant prevention and control measures and policies, thereby improving the ability of urban traffic to respond to public health emergencies. © ASCE.

Soluble Signals to Improve Endothelial Integrity in the Lung

Disorders in pulmonary vascular integrity are a prominent feature in many lung diseases, including acute respiratory distress syndrome (ARDS), capillary leak syndrome, and COVID19. Paracrine signals are enriched in the lung and are critically important in regulating the homeostasis of the functional pulmonary microvasculature. Here, we employed single-cell RNA-sequencing (scRNAseq) to study ligand and receptor interactions in the native human lung microvascular niche, and identified soluble factors that are critical in endothelial integrity. The scRNAseq data reveals a total of 47 cell populations consisting of five vascular endothelial subtypes in human lungs, including general capillary EC, aerocyte capillary EC (EC aCap), arterial EC, pulmonary venous EC, and systemic venous EC. Using EC aCap as a signal receiving core (Receptors) and the putative adjacent cell types (alveolar fibroblast, ATI, ATII, pericyte, plasma cell, etc.) in the EC aCap niche as senders (Ligands), we identified that SLIT2-ROBO4, ANGPT1-TIE1, ADM-RAMP2, VEGFD-KDR, and BMP5-BMPR2 are the top specific and abundant pairs in the niche. Immunostaining and ELISA assays confirmed their spatial information and secretion level. Furthermore, upon treatment with these ligands, real-time resistance recorded using an electric cell-substrate impedance sensing (ECIS) system revealed that VEGFD, ANGPT1 (angiopoietin 1), and ADM (adrenomedullin) could markedly increase the electrical resistance of human lung microvascular, arterial, and venous endothelial cells, suggesting their strong impact on the endothelial barrier function. Deciphering the cell-cell soluble signals that improve endothelial integrity in human lungs lays the foundation for uncovering the pathogenesis of pulmonary vascular disorders and the development of ex vivo functional lung vasculature.

Improving Representation Consistency with Pairwise Loss for Masked Face Recognition

Given the coronavirus disease (COVID-19) pandemic, people need to wear masks to protect themselves and reduce the spread of COVID, which brings new challenge to the traditional face recognition task. Since features like the nose and mouth, which are well distinguishable, are hidden under the mask, traditional methods are no longer simply applicable, even though they once achieved a high degree of accuracy. In response to this problem, the Masked Face Recognition Challenge & Workshop (MFR) was held in conjunction with the International Conference on Computer Vision (ICCV) 2021. This article details a method that combining the classic ArcFace and pairwise loss to target the new masked face recognition task. So far, our method has achieved the second place in the competition.

Evaluation of COVID-19 control strategies in different countries and periods based on an adaptive PSO-SEIR model

The COVID-19 pandemic has battered the world in more than 100 countries and regions due to its deadly and high transmission. How to control or limit the first and possible second wave of the infection has become an essential problem based on the control strategies implemented globally. This study presented a model to evaluate the efficiency of strategies based on an improved multi-stage SEIR (susceptible-exposed-infectious-recovered) model considering quarantine factor, treatment delay, transmission risk by the exposed, and time. The particle swarm optimization (PSO) algorithm with an adaptive weight strategy is adopted to find the SEIR model's critical parameters associated with the control strategies based on the confirmed cases, the cured cases, and the death cases in the Chinese mainland, Italy, Spain, and Germany. The model was verified by the coefficients of correlation (R-2) between the predicted results using parameters found by PSO and the actual data on the confirmed, the death, and the cured cases. The R(2)s are all greater than 0.93 in the Chinese mainland, Italy, Spain, and Germany, showing a good accuracy of the proposed model. Base on the data of analyzed countries, PSO finds the incubation period of COVID-19 is approximately 5.1 d, which is consistent with other literatures. Besides, the period from exposure to medical care delivery is the most significant for controlling the transmission, followed by the quarantined rate according to our model. The effective reproduction number reduces from 3.9 to 1.4 while the delivery period shortens from 13 to 1 d, even without considering the effect of quarantined rate and crowd protection awareness, indicating the importance of acid testing. Moreover, the effective reproduction number is smaller than 1 when the delivery period is 1 d and the quarantined rate is higher than 0.1, which shows the transmission of COVID-19 can be contained in these conditions. Furthermore, the establishment of Fangcang shelter hospitals and the implication of aided diagnosis guideline of COVID-19 gradually reduce the period to the hospital for patients in Hubei Province from 16 to 1-2 d. In addition, the efficiency of strategies among Italy, Spain, and Germany shows that Germany reached a better condition in comparison with others, and the number of confirmed cases in each country can drop by nearly 1/3 as the protection awareness of the population rises from 0.25 to 0.69, through reducing social activities, keeping social distance, and wearing masks, indicating the importance of government advertisement, education, etc. This study might help the governments to make strategies to limit the spreading of COVID-19 or potential outbreak of emerging infectious diseases in the future.

Dominant transmission route of SARS-CoV-2 and its implication to indoor environment

The exact main transmission route(s) for SARS-CoV-2 remains to be determined after more than 12 months into the once-in-a-century Coronavirus Disease 2019 (COVID-19) pandemic. Following the first reported infected case of COVID-19 a year ago, different intervention strategies have been adopted worldwide. A "just in case" approach may overkill with significant economic and societal losses, while an underkill approach may result in significant infection. An adequate intervention demands the knowledge of the dominant transmission route(s) of SARS-CoV-2. In this perspective, the definition and categorization of transmission routes for respiratory infection are discussed, and a new categorization is proposed. Among the traditional definitions of various transmission routes, the concept of contact transmission appears to be the most problematic. The short-range aerosol route was not considered, certainly not in the traditional aerosol transmission, which generally implies a possible long-range transmission. It is not desirable to lump short-range aerosol transmission into aerosol (airborne) transmission as the preventive measures differ between the two. In a recent mechanistic study, the short-range inhalation route was shown to dominate the exposure of respiratory infection during close contact, while spray transmission is only significant at a very close distance (< 0.5 m). Our suggested new categorization of basic transmission routes of respiratory infection is transfer-process-focused. The three basic routes are the (drop) spray route as infection transmitted by spray and deposition of virus-laden respiratory drops expelled from an infected person onto the mucosal surfaces (e.g., eyes, nose and mouth) of a susceptible individual, (aerosol) inhalation route as infection of a susceptible individual via inhalation of virus-laden respiratory droplets at both short-range and long-range, i.e., aerosols that can suspend in the air, and (surface) touch route as infection transmitted by hand touch of a surface (can be both animate and inanimate) which was contaminated with the virus-laden respiratory drops or droplets, followed by his/her hands touching mucosa, resulting in self-inoculation. The threshold diameter of drops in spray transmission is 50-100 μm. These three newly defined routes may be simply referred to as spray, inhalation and touch transmission. An opportunistic airborne transmission mechanism is hypothesized for SARS-CoV-2 spread, which can explain the following major observations of the infection pattern so far, i.e., transmission at close range seems to dominate and social (physical) distancing has worked;distant transmission has been reported occasionally, which often leads to super spreading events;mass face masking has also worked;most infection occurred indoors;and finally infection that occurred outdoors has been rare. The opportunistic airborne transmission hypothesis is also supported by a recent mechanistic study of exposure of the susceptible to exhaled droplets. If such a hypothesis can be further verified, the importance of building ventilation becomes obvious. The research needs of the improved indoor environment in the post-pandemic period are also speculated. Mankind will reflect deeply on the needs of future indoor environment, or broadly city design, in terms of balancing the needs of economics and sustainability of humanity, asking what has gone wrong indoors, and refocusing on human health, particularly for possible environmental intervention mode of operation for COVID-19 and other novel infectious diseases. Opportunities or possibilities exist that the buildings may be equipped with better ventilation and filtration, e.g. to equip the building system with pandemic time operation mode (e.g. much more enhanced ventilation, availability of HEPA, UVGI), to design a better control of indoor humidity, to ensure recirculation of air with good filtration or use fan-coil system with a separate ventilation system, to develop safe drainage systems in high-rise buildings with monitored foul gas low, to apply non-touchable high touch surfaces such as automatic door opening and remote lift button, automatic occupancy control, to reconsider open plan office design, and to design for easy future facility management and upgrade etc. Opportunities of determining transmission routes using big data, artificial intelligence (AI) and the internet to things (IoT) are also briefly mentioned so that next time the exact transmission routes can be determined rapidly and accurately. © 2021, Science Press. All right reserved.

Evaluation of COVID-19 control strategies in differentcountries and periods based on an adaptive PSO-SEIR model

The COVID-19 pandemic has battered the world in more than 100 countries and regions due to its deadly and high transmission. How to control or limit the first and possible second wave of the infection has become an essential problem based on the control strategies implemented globally. This study presented a model to evaluate the efficiency of strategies based on an improved multi-stage SEIR (susceptible-exposed-infectious-recovered) model considering quarantine factor, treatment delay, transmission risk by the exposed, and time. The particle swarm optimization (PSO) algorithm with an adaptive weight strategy is adopted to find the SEIR model's critical parameters associated with the control strategies based on the confirmed cases, the cured cases, and the death cases in the Chinese mainland, Italy, Spain, and Germany. The model was verified by the coefficients of correlation (R2) between the predicted results using parameters found by PSO and the actual data on the confirmed, the death, and the cured cases. The R2s are all greater than 0.93 in the Chinese mainland, Italy, Spain, and Germany, showing a good accuracy of the proposed model. Base on the data of analyzed countries, PSO finds the incubation period of COVID-19 is approximately 5.1 d, which is consistent with other literatures. Besides, the period from exposure to medical care delivery is the most significant for controlling the transmission, followed by the quarantined rate according to our model. The effective reproduction number reduces from 3.9 to 1.4 while the delivery period shortens from 13 to 1 d, even without considering the effect of quarantined rate and crowd protection awareness, indicating the importance of acid testing. Moreover, the effective reproduction number is smaller than 1 when the delivery period is 1 d and the quarantined rate is higher than 0.1, which shows the transmission of COVID-19 can be contained in these conditions. Furthermore, the establishment of Fangcang shelter hospitals and the implication of aided diagnosis guideline of COVID-19 gradually reduce the period to the hospital for patients in Hubei Province from 16 to 1-2 d. In addition, the efficiency of strategies among Italy, Spain, and Germany shows that Germany reached a better condition in comparison with others, and the number of confirmed cases in each country can drop by nearly 1/3 as the protection awareness of the population rises from 0.25 to 0.69, through reducing social activities, keeping social distance, and wearing masks, indicating the importance of government advertisement, education, etc. This study might help the governments to make strategies to limit the spreading of COVID-19 or potential outbreak of emerging infectious diseases in the future. © 2021, Science Press. All right reserved.

Association of Padua prediction score with in-hospital prognosis in COVID-19 patients.

BACKGROUND: Nearly 20% novel coronavirus disease 2019 (COVID-19) patients have abnormal coagulation function. Padua prediction score (PPS) is a validated tools for venous thromboembolism (VTE) risk assessment. However, its clinical value in COVID-19 patients' evaluation was unclear. METHODS: We prospectively evaluated the VTE risk of COVID-19 patients using PPS. Demographic and clinical data were collected. Association of PPS with 28-day mortality was analyzed by multivariate logistic regression and Kaplan-Meier analysis. RESULTS: Two hundred and seventy-four continuous patients were enrolled, with total mortality of 17.2%. Patients in high PPS group, with significantly abnormal coagulation, have a higher levels of interleukin 6 (25.27 vs. 2.55 pg/ml, P < 0.001), prophylactic anticoagulation rate (60.7% vs. 6.5%, P < 0.001) and mortality (40.5% vs. 5.9%, P < 0.001) when compared with that in low PPS group. Critical patients showed higher PPS (6 vs. 2 score, P < 0.001) than that in severe patients. Multivariate logistic regression revealed the independent risk factors of in-hospital mortality included high PPS [odds ratio (OR): 7.35, 95% confidence interval (CI): 3.08-16.01], increased interleukin-6 (OR: 11.79, 95% CI: 5.45-26.20) and elevated d-dimer (OR: 4.65, 95% CI: 1.15-12.15). Kaplan-Meier analysis indicated patients with higher PPS had a significant survival disadvantage. Prophylactic anticoagulation in higher PPS patients shows a mild advantage of mortality but without statistical significance (37.1% vs. 45.7%, P = 0.42). CONCLUSION: Higher PPS associated with in-hospital poor prognosis in COVID-19 patients. Prophylactic anticoagulation showed a mild advantage of mortality in COVID-19 patients with higher PPS, but it remain to need further investigation.