Insight into the microplastics release from disposable face mask: Simulated environment and removal strategy

The fight against the COVID-19 epidemic significantly raises the global demand for personal protective equipment, especially disposable face masks (DFMs). The discarded DFMs may become a potential source of microplastics (MPs), which has attracted much attention. In this work, we identified the detailed source of MPs released from DFMs with laser direct infrared spectroscopy. Polypropylene (PP) and polyurethane (PU) accounted for 24.5% and 57.1% of released MPs, respectively. The melt-blown fabric was a dominant MPs source, however, previous studies underestimated the contribution of mask rope. The captured polyethylene terephthalate (PET), polyamide (PA), polyethylene (PE), and polystyrene (PS) in airborne only shared 18.4% of released MPs. To deepen the understanding of MPs release from medical mask into the aquatic environment, we investigated the effects of environmental factors on MPs release. Based on regression analysis, the effects of temperature, incubation time, and wearing time significantly affect the release of MPs. Besides, acidity, alkalinity, sodium chloride, and humic acid also contributed to the MPs release through corroding, swelling, or repulsion of fibers. Based on the exposure of medical mask to simulated environments, the number of released MPs followed the order: seawater > simulated gut-fluid > freshwater > pure water. Considering the risk of MPs released from DFMs to the environment, we innovatively established a novel flotation removal system combined with cocoamidopropyl betaine, achieving 86% removal efficiency of MPs in water. This work shed the light on the MPs release from DFMs and proposed a removal strategy for the control of MPs pollution.

Intervention of Physical Activity for University Students with Anxiety and Depression during the COVID-19 Pandemic Prevention and Control Period: A Systematic Review and Meta-Analysis

(1) Background: Although physical activity has been widely recognized as an effective way to improve anxiety and depression, we lack a systematic summary of research on improving anxiety and depression during the COVID-19 pandemic. The study aims to systematically analyze how physical activity impacts on this situation in college students during COVID-19. (2) Methods: Both Chinese and English databases (PubMed the Cochrane Library, EMBASE, Web of Science, Scopus, Chinese National Knowledge Infrastructure, Wanfang) were analyzed. All the randomized controlled trials (RCTs) about physical activity intervention for this were included. We received eight eligible RCT experiments before the retrieval time (4 October 2022) in the meta-analysis. (3) Results: Physical activity benefits for college students with significant anxiety were (SMD = -0.50; 95% CI = -0.83 to -0.17; I² = 84%; p < 0.001; Z = 2.98;) and depression (SMD = -0.62; 95% CI = -0.99 to -0.25; I² = 80.7%; p < 0.001; Z = 3.27). Subgroup analyses showed physical activity of different intensities significantly impacted on improving college students' depression and anxiety, but physical activity of 6 < 9 Mets intensity had a greater effect on anxiety than on depression. Interventions of eight weeks or less performed better than those of over eight weeks while interventions less than four times per week had a significant effect on improving the situation. The overall effect of a single intervention of 30 min was more effective than one of over 60 min. (4) Conclusion: Physical activities can effectively improve the situation of anxiety and depression for college students during the COVID-19 pandemic. However, a higher quality RCT experiment is needed to prove it.

Temporal changes in health-related lifestyle during the COVID-19 epidemic in Finland - a series of cross-sectional surveys

BACKGROUND

Public health recommendations and governmental restrictions during the COVID-19 epidemic have affect everyday life. This study aimed to examine temporal changes in health-related lifestyle and the accumulation of positive and negative changes in the key lifestyle factors (vegetable consumption, leisure-time physical activity, sleeping, alcohol consumption, smoking) in the same individuals among Finnish adults during the epidemic.

METHODS

This study was based on a series of cross-sectional surveys conducted between April 2020 and June 2021 to investigate antibody levels for the new coronavirus in the population. In each survey, a random sample of adults (18 to 69 years) from five university hospital regions were invited. A total of 5655 (response rate 32%) responded to the questionnaire including questions on lifestyle changes during epidemic.

RESULTS

On average one-sixth of respondents (17%) reported at least two negative changes in the key lifestyle factors during the study period. An increase in snacking and sleep problems and decrease in leisure-time physical activity and active commuting to work were the most common of individual negative changes. The proportion of negative changes in physical activity increased as the epidemic drags on. In contrast, on average every seventh of the respondents (14%) reported at least two positive lifestyle changes in the key lifestyle factors. The most common individual positive changes were increased consumption of fruit, berries and vegetables and decreased consumption of alcohol. More negative changes were reported on average, when both negative and positive changes in the key lifestyle factors were summed. The most negative changes were reported in the late 2020.

CONCLUSION

The results of the present study suggest that the lifestyle changes during the COVID-19 epidemic have been diverse being on average more commonly unfavorable than favorable for health. The deteriorated epidemic situation in the late 2020 and, on the other hand, prolonged epidemic predisposed to negative lifestyle changes. Further studies are important to examine whether these changes are maintained over time and to identify the factors that contribute to changes and their accumulation in the same individuals. Health promotion actions are needed to prevent the long-term effects of the epidemic on health and welfare.

Effect of decrease of physical activity on depression and anxiety after the COVID-19 lockdown: A survey study

Purpose

We focused on changes in the amount of physical activity (PA) and depression and anxiety symptoms in people, who were previously regularly physically active, as they were all members of fitness centers at time of lockdown because of COVID-19.

Materials and methods

We sampled 150 fitness center members, tested individually in facilities of fitness centers. Depression and anxiety were measured with subscales of Personality Assessment Inventory (PAI) and PA was measured with global physical activity questionnaire (GPAQ).

Results

We found that depression (t = -1.97; p < 0.05) and anxiety (t = -2.66; p < 0.05) was more present in female participants than male participants, single participants experienced more depression (t = 2.04; p < 0.05) than participants in relationship, unemployed participants experienced more depression (F = 3,24; p < 0.05) and anxiety (F = 5,32; p < 0.01) than employed participants and participants with lower levels of education experienced higher levels of affective depression (F = 3,42; p < 0.05) and physiological anxiety (F = 3,72; p < 0.05) than participants with higher levels of education. Finally, we found that mental health can be influenced by changes in amount of movement-both anxiety (p < 0.05) and depression (p < 0.05) (in whole and its specific dimensions) increased for male participants when there is less strenuous work-related activity, less walking, or cycling to work and when they would spend more time each day sitting. For female participants, affective depression (t = 3.78; p < 0.01) and anxiety (t = 3.23; p < 0.01) increased with increased sitting time. Ex-competitive athletes are particularly immune to anxiety (t = -2.18; p < 0.05) and depression (t = -2.09; p < 0.05).

Discussion

As in some previous studies, our results show that because of lockdown, the most endangered groups for mood disorders are women, singles, unemployed and students, uneducated people and those, who had less PA, and more sitting time. Additionally, those who had some sport competitive history are less endangered for depression and anxiety.

Conclusion

Isolation has great impact on mental health, the most effective solution to stress relief and anxiety is physical exercise, which was limited or non-existent in the time of pandemic. Ex-professional athletes are especially immune to anxiety and depression in events such as COVID-19 lockdown. For future studies we recommend focusing on likelihood of increased depression and anxiety levels in individuals, who were physically active before the isolation period.

Assessing the "negative effect" and "positive effect" of COVID-19 in China

The COVID-19 pandemic lockdowns led to a sharp drop in socio-economic activities in China in 2020, including reductions in fossil fuel use, industry productions, and traffic volumes. China's economy suffered a serious negative effect from COVID-19. However, there is a "positive effect" on CO₂ emissions reduction. Here, for the first time, this paper constructs a new model named "Weighted Multi-regional Hypothetical Extraction Method (WMHEM)" based on a multiregional input-output model. It not only solves the problems of traditional HEM methods such as improper use of assumptions, excessive reliance on industry intermediate input, but also accurately reflects the impact of external shocks on the inter-industry linkages. By using the monthly economic data of each provinces in China during COVID-19 (except Hong Kong，Macao and Taiwan) an the latest Multi-regional input-output tables, the "economic negative effect" and "CO₂ emission positive effect" under COVID-19 in China are measured. Results show that COVID-19 lockdown was estimated to have reduced China's CO₂ emissions substantially between January and March in 2020, with the largest reductions in February. With the spread of coronavirus controlled, China's CO₂ emissions rebounded in April. In addition, key emission reduction sectors and key development encouraged sectors are selected by combining "economic negative effect" and "CO₂ emission positive effect" during COVID-19. Therefore, policies recommendations are put forward based on forward and backward linkages respectively which are from two ends of the supply chain to turn pandemic-related CO₂ emissions declines into firm climate action.

Meaning in life among Chinese undergraduate students in the post-epidemic period: A qualitative interview study

Background

COVID-19 epidemic has lasted for nearly 3 years, and revolutionized social life. In the study, in-depth interviews were conducted with Chinese undergraduate students to explore their understanding and experience of meaning in life. Meaning of life is interpreted from four aspects: life goals, life value, life enthusiasm, and life freedom. These four aspects are independent yet interrelated. Based on the free grasp of life, individuals explore and pursue the true meaning of life goals, acquire life value in evaluating the completion of life goals, and subsequently experience enthusiasm for life. Life enthusiasm and the perception of life value can help individuals to further understand and possess their meaning of life.

Materials and methods

The present study adopts the qualitative method to understand the experience of meaning in life among Chinese undergraduate students. Semi-structured interviews were conducted, and six people participated the study. The Grounded Theory was adopted to analyze the qualitative data.

Results

(1) Chinese undergraduates had clear life goals and obtained a certain sense of achievement and satisfaction when striving for these goals. (2) The life value of Chinese undergraduates was mainly to their families, but there was also a willingness to make due contributions to the country and society. (3) Chinese undergraduates' feelings about life were polarized, but they all expressed the view of "living in the moment and cherishing the present." (4) Chinese undergraduate students see life freedom as freedom of choice and generally believed that COVID-19 did not restrict their lives very much. (5) Chinese undergraduate students gained a deeper understanding of meaning in life after this major public health emergency.

Characteristics of the school adaptation of college freshmen during the COVID-19 epidemic

Few studies have actually explored the impact of the COVID-19 pandemic on mental health in college students, although many studies have suggested that the COVID-19 pandemic poses a great threat to people's mental health in many cohorts. Furthermore, college students may be a particularly vulnerable cohort that needs more attention and access to psychological services due to the psychological changes involved in the transition to college and the characteristics of college students' study habits and lifestyle. Therefore, investigating the basic characteristics of the impact of the COVID-19 pandemic on college freshmen is of great practical importance and has theoretical implications for the identification and provisioning of services to vulnerable cohorts. A total of 5,818 college freshmen completed the College Student Adaptability Inventory. The results suggest that the mean detection rate of the seven dimensions of undergraduate maladjustment to university is 27.13%. Specifically, livelihood self-management adaptability has the highest detection rate (48.93%), while environmental general evaluation has the lowest detection rate (9.81%). Moreover, the school adaptation of college freshmen is impacted by gender, number of siblings, and family socioeconomic status (SES). Specifically, students who are female, an only child, and have a lower SES have lower levels of school adaptation. However, the school adaptation of college freshmen is not influenced by minority status or left-behind status. The findings of the present study suggest that the maladaptation of college freshmen has been a common phenomenon in China during the COVID-19 epidemic. Prevention programs may be most helpful if they pay more attention to effective intervention efforts for students who are female, an only child, and have a lower SES.

Growth-Related Responses to the Threat of COVID-19 among Adolescents

The main objective of our study was to determine whether the experience of the types of pandemic threats included in the study, could activate development responses among adolescents and what the role of the level of stress experienced during the COVID-19 pandemic is in the process of post-traumatic PTG growth. We also made an attempt to investigate whether personality traits and gender were predictors of PTG growth in adolescents. Therefore, the theoretical bases for the interpretation of the obtained results are models of post-traumatic growth (PTG), mainly by Calhoun and Tedeschi. The research was conducted in March 2020. The study subjects were 405 adolescents aged 14 to 20 years, with an average age of 17 years, of whom 59% were females and 41% were males. The following methods were used in the study: IPIP-BFM-20 to estimate five personality traits, PSS- to diagnose perceived stress, and an in-house questionnaire of pandemic threats experienced by adolescents (KŻP). The results showed that the various types of 'pandemic' threats (threats to life, family, and lifestyle) are positive predictors of growth-related changes; additionally, such factors as personality traits (here: extroversion), stress level, and gender had a positive mediating effect on growth-related changes. It was also possible to show that out of the four dimensions of post-traumatic growth, three could be activated under pandemic conditions. These were: changes in relationships with others, greater appreciation of everyday life, and spiritual changes. Changes in self-perception-one of the dimensions of post-traumatic growth, were not activated due to experiencing three types of pandemic threats.

The influence of COVID-19 epidemic on BDI volatility: An evidence from GARCH-MIDAS model

In this study, we use the sample data from Jan 22, 2020 to Jan 21, 2022 to investigate the impacts of added infection number on the volatility of BDI. Under this structure, the control variables (freight rate, Brent crude oil price, container idle rate, port congestion level, global port calls) are added to test whether the information contained in the added infection number is covered. In the GARCH-MIDAS model, we divide the volatility of BDI into the long-term and short-term components, then employ in the least squares regression to empirically test the influences of added infection number on the volatility. From the analysis, we find the added infection numbers effectively impact the BDI volatility. In addition, whether the freight rate, Brent crude oil price, container idle rate, port congestion level, global port calls and other variables are considered alone or at the same time, further the added infection number still significantly influences the volatility of BDI. By studying the ability of the confirmed number to explain the volatility of BDI, a new insight is provided for the trend prediction of BDI that the shipping industry can take the epidemic development of various countries as a reference to achieve the purpose of cost or risk control.

Public engagement in decision-making regarding the management of the COVID-19 epidemic: Views and expectations of the 'publics'

Background

In the management of epidemics, like COVID‐19, trade‐offs have to be made between reducing mortality and morbidity and minimizing socioeconomic and political consequences. Traditionally, epidemic management (EM) has been guided and executed attentively by experts and policymakers. It can, however, still be controversial in the public sphere. In the last decades, public engagement (PE) has been successfully applied in various aspects of healthcare. This leads to the question if PE could be implemented in EM decision‐making.

Methods

From June to October 2020, seven deliberative discussion focus groups were executed with 35 Dutch citizens between 19 and 84 years old. Their views on PE in COVID‐19 management were explored. The deliberative approach allows for the education of participants on the topic before the discussion. The benefits, barriers, timing and possible forms of PE in EM were discussed.

Results

Almost all participants supported PE in EM, as they thought that integrating their experiences and ideas would benefit the quality of EM, and increase awareness and acceptance of measures. A fitting mode for PE was consultation, as it was deemed important to provide the public with possibilities to share ideas and feedback; however, final authority remained with experts. The publics could particularly provide input about communication campaigns and control measures. PE could be executed after the first acute phase of the epidemic and during evaluations.

Conclusions

This paper describes the construction of an empirically informed framework about the values and conditions for PE in EM from the perspective of the public. Participants expressed support to engage certain population groups and considered it valuable for the quality and effectiveness of EM; however, they expressed doubts about the feasibility of PE and the capabilities of citizens. In future studies, these results should be confirmed by a broader audience.

Patient or Public Contribution

No patients or members of the public were involved in the construction and execution of this study. This study was very exploratory, to gain a first insight into the views of the public in the Netherlands, and will be used to develop engagement practices accordingly. At this stage, the involvement of the public was not yet appropriate.

The Structure of the Relationship between Physical Activity and Psychosocial Functioning of Women and Men during the COVID-19 Epidemic in Poland

Since the coronavirus disease (COVID-19) pandemic is a serious crisis in many countries around the world, it is important to conduct empirical research aimed at identifying risks and factors protecting the functioning of people affected by it. For this reason, the goals of the present research were to determine the level of physical activity and the severity of symptoms characteristic of mental disorders, cognitive disorders and the quality of social functioning, as well as the structure of the relationship between physical activity and psychosocial functioning of 226 women and 226 men during the COVID-19 epidemic in Eastern Poland. The research was conducted using the IPAQ-SF Questionnaire, GHQ-28 Questionnaires, TUS Test-6/9 version, the original SFS Scale and a self-developed sociodemographic survey. The collected data indicate that women as compared to men show lower levels of weekly physical activity, walking, moderate activity, vigorous activity and quality of functioning in family relationships, but higher severity of mental health disorders, somatic symptoms, functional disorders, depressive symptoms, cognitive disorders, perceptual work disorders, attention deficits and higher quality of functioning in work relationships. On the other hand, the structural model indicates that physical activity, interacting with mental health disorders and cognitive disorders, is positively associated with the social functioning of the respondents, and gender is the moderator of the occurring dependencies. This suggests that physical activity adapted to the condition of health may be an important component of gender-individualized psychopreventive interventions.

Resumption of school after lockdown in COVID-19 pandemic: Three case reports

BACKGROUND

Students in the 9^th grade of junior high school in Changsha were under a 75 d lockdown due to the coronavirus disease 2019 (COVID-19) pandemic. After the resumption of school post-lockdown, the 9^th grade students in Changsha faced the entrance physical examination test for senior high school.

CASE SUMMARY

We report on 3 cases of occult fracture on the same site in adolescents of the same grade since resumption of school after the lockdown from the COVID-19 pandemic. Three students in the 9^th grade of junior high school who were facing the physical examination in 2 wk were diagnosed with an occult fracture of the distal femur.

CONCLUSION

It is recommended that the students, parents, education providers and policy makers should all pay attention to the physical exercise of students when the resumption of school after lockdown occurs and they should be aware of occult fractures when the adolescents have pain after physical exercise.

Controlling Multiple COVID-19 Epidemic Waves: An Insight from a Multi-scale Model Linking the Behaviour Change Dynamics to the Disease Transmission Dynamics

COVID-19 epidemics exhibited multiple waves regionally and globally since 2020. It is important to understand the insight and underlying mechanisms of the multiple waves of COVID-19 epidemics in order to design more efficient non-pharmaceutical interventions (NPIs) and vaccination strategies to prevent future waves. We propose a multi-scale model by linking the behaviour change dynamics to the disease transmission dynamics to investigate the effect of behaviour dynamics on COVID-19 epidemics using game theory. The proposed multi-scale models are calibrated and key parameters related to disease transmission dynamics and behavioural dynamics with/without vaccination are estimated based on COVID-19 epidemic data (daily reported cases and cumulative deaths) and vaccination data. Our modeling results demonstrate that the feedback loop between behaviour changes and COVID-19 transmission dynamics plays an essential role in inducing multiple epidemic waves. We find that the long period of high-prevalence or persistent deterioration of COVID-19 epidemics could drive almost all of the population to change their behaviours and maintain the altered behaviours. However, the effect of behaviour changes fades out gradually along the progress of epidemics. This suggests that it is essential to have not only persistent, but also effective behaviour changes in order to avoid subsequent epidemic waves. In addition, our model also suggests the importance to maintain the effective altered behaviours during the initial stage of vaccination, and to counteract relaxation of NPIs, it requires quick and massive vaccination to avoid future epidemic waves.

Sex Differences in Clinical Parameters, Pharmacological and Health-Resource Utilization in a Population With Hypertension Without a Diagnosis of COVID-19

Objectives: Determine the changes in clinical, pharmacological and healthcare resource use parameters, between the 6 months prior to the lockdown and the 6 months following its end, in a population with hypertension who did not have a diagnosis of COVID-19. Methods: Real world data observational study of 245,979 persons aged >16 years with hypertension in Aragon (Spain). Clinical (systolic-diastolic blood pressure, estimated glomerular filtration rate (eGFR), blood creatinine, cholesterol, triglycerides and anthropometric measures); pharmacological (diuretics, calcium channel antagonists, and ACE inhibitors); and utilization of healthcare resources were considered. We performed the Student's T-test for matched samples (quantitative) and the Chi-squared test (qualitative) to analyze differences between periods. Results: SBP, DBP, parameters of renal function and triglycerides displayed a significant, albeit clinically irrelevant, worsening in women. In men only DBP and eGFR showed a worsening, although to a lesser extent than in women. Certain antihypertensive drugs and health-resource utilization remained below pre-pandemic levels across the 6 months post-lockdown. Conclusion: Changes in lifestyles, along with difficulties in access to routine care has not substantially compromised the health and quality of life of patients with hypertension.

Multifunctional Flexible Humidity Sensor Systems Towards Noncontact Wearable Electronics

In the past decade, the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare, Internet of Things, human-machine interfaces, artificial intelligence and soft robotics. Among them, flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change. This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring. Four categories of humidity sensors are highlighted based on resistive, capacitive, impedance-type and voltage-type working mechanisms. Furthermore, typical strategies including chemical doping, structural design and Joule heating are introduced to enhance the performance of humidity sensors. Drawing on the noncontact perception capability, human/plant healthcare management, human-machine interactions as well as integrated humidity sensor-based feedback systems are presented. The burgeoning innovations in this research field will benefit human society, especially during the COVID-19 epidemic, where cross-infection should be averted and contactless sensation is highly desired.

A Study on the Correlation Between Undergraduate Students' Exercise Motivation, Exercise Self-Efficacy, and Exercise Behaviour Under the COVID-19 Epidemic Environment

The outbreak of COVID-19 epidemic has influenced human beings from various aspects including physical exercise behaviours. This study aims to explore the influence of the COVID-19 epidemic on exercise self-efficacy and exercise behaviour, as well as the intermediary effects of exercise motivation. A sample of 1,115 undergraduate students was investigated using the physical exercise behaviour scale, exercise self-efficacy scale, and exercise motivation scale, combined with the COVID-19 epidemic environment as an influencing factor. SPSS was used for statistical analysis and AMOS for the prediction model building. Logical analysis was undertaken to sort out and analyse the data. The structural equation model reveals that exercise self-efficacy has a positive effect on exercise motivation and exercise behaviour. Meanwhile, the COVID-19 epidemic environment negatively influences exercise behaviour through the intermediary role of exercise self-efficacy and exercise motivation. Moreover, the intermediary effect of exercise self-efficacy is greater than that of exercise self-efficacy and exercise motivation. This study provides both theoretical implications and practical guidelines for society and undergraduate students to improve their exercise behaviour during epidemic.

International student perceptions of online medical education during the COVID-19 epidemic

This study aimed to investigate how international students enrolled on medical and surgical bachelor's degree programs (MBBS) in China perceived online medical education course, compared to native Chinese students during the Covid-19 pandemic. The perceptions of 38 MBBS and 31 Chinese sophomores were surveyed using the Chaoxing platform. The international student group's mean satisfaction with online teaching was 2.737 on a 5-point scale, much lower than the Chinese students' mean score of 4.355 (p < 0.05). Similarly, the international students expressed less satisfaction than the Chinese learners with other aspects of the course, including the teacher's level, at 3.964 ± 0.818 versus 4.445 ± 0.548 (p < 0.05); curriculum organization, at 3.651 ± 0.848 versus 4.333 ± 0.568 (p < 0.05); and self-learning level, at 3.634 ± 0.996 versus 3.686 ± 0.949 (p > 0.05), respectively. There were also noteworthy differences between the progress made by the international students in Chinese language learning, which was positively correlated with satisfaction with teaching on the online medical education (p < 0.05). The results suggest that, while online teaching was a necessary response to the Covid-19 pandemic, satisfaction with this mode of education is lower among international students than their Chinese counterparts.

[Influence of COVID-19 Prevention and Control Measures on PM2.5 Concentration, Particle Size Distribution, Chemical Composition, and Source in Zhengzhou, China]

The COVID-19 lockdown was a typical occurrence of extreme emission reduction, which presented an opportunity to study the influence of control measures on particulate matter. Observations were conducted from January 16 to 31, 2020 using online observation instruments to investigate the characteristics of PM_2.5 concentration, particle size distribution, chemical composition, source, and transport before (January 16-23, 2020) and during (January 24-31, 2020) the COVID-19 lockdown in Zhengzhou. The results showed that the atmospheric PM_2.5 concentration decreased by 4.8% during the control period compared with that before the control in Zhengzhou. The particle size distribution characteristics indicated that there was a significant decrease in the mass concentration and number concentration of particles in the size range of 0.06 to 1.6 μm during the control period. The chemical composition characteristics of PM_2.5 showed that secondary inorganic ions (sulfate, nitrate, and ammonium) were the dominant component of PM_2.5, and the significant increase in PM_2.5 was mainly owing to the decrease in NO₃^- concentration during the control period. The main sources of PM_2.5 identified by the positive matrix factorization (PMF) model were secondary sources, combustion sources, vehicle sources, industrial sources, and dust sources. The emissions from vehicle sources, industrial sources, and dust sources decreased significantly during the control period. The results of analyses using the backward trajectory method and potential source contribution factor method indicated that the effects of transport from surrounding areas on PM_2.5 concentration decreased during the control period. In summary, vehicle and industrial sources should be continuously controlled, and regional combined prevention and control should be strengthened in the future in Zhengzhou.

Monitoring COVID-19 spread in Prague local neighborhoods based on the presence of SARS-CoV-2 RNA in wastewater collected throughout the sewer network

Many reports have documented that the presence of SARS-CoV-2 RNA in the influents of municipal wastewater treatment plants (WWTP) correlates with the actual epidemic situation in a given city. However, few data have been reported thus far on measurements upstream of WWTPs, i.e. throughout the sewer network. In this study, the monitoring of the presence of SARS-CoV-2 RNA in Prague wastewater was carried out at selected locations of the Prague sewer network from August 2020 through May 2021. Various locations such as residential areas of various sizes, hospitals, city center areas, student dormitories, transportation hubs (airport, bus terminal), and commercial areas were monitored together with four of the main Prague sewers. The presence of SARS-CoV-2 RNA was determined by reverse transcription - multiplex quantitative polymerase chain reaction (RT-mqPCR) after the precipitation of nucleic acids with PEG 8,000 and RNA isolation with TRIzol™ Reagent. The number of copies of the gene encoding SARS-CoV-2 nucleocapsid (N1) per liter of wastewater was compared with the number of officially registered COVID-19 cases in Prague. Although the data obtained by sampling wastewater from the major Prague sewers were more consistent than those obtained from the small sewers, the correlation between wastewater-based and clinical-testing data was also good for the residential areas with more than 7,000 registered inhabitants. It was shown that monitoring SARS-CoV-2 RNA in wastewater sampled from small sewers could identify isolated occurrences of COVID-19-positive cases in local neighborhoods. This can be very valuable while tracking COVID-19 hotspots within large cities.

Monitoring COVID-19 spread in Prague local neighborhoods based on the presence of SARS-CoV-2 RNA in wastewater collected throughout the sewer network

Many reports have documented that the presence of SARS-CoV-2 RNA in the influents of municipal wastewater treatment plants (WWTP) correlates with the actual epidemic situation in a given city. However, few data have been reported thus far on measurements upstream of WWTPs, i.e. throughout the sewer network. In this study, the monitoring of the presence of SARS-CoV-2 RNA in Prague wastewater was carried out at selected locations of the Prague sewer network from August 2020 through May 2021. Various locations such as residential areas of various sizes, hospitals, city center areas, student dormitories, transportation hubs (airport, bus terminal), and commercial areas were monitored together with four of the main Prague sewers. The presence of SARS-CoV-2 RNA was determined by reverse transcription - multiplex quantitative polymerase chain reaction (RT-mqPCR) after the precipitation of nucleic acids with PEG 8,000 and RNA isolation with TRIzol™ Reagent. The number of copies of the gene encoding SARS-CoV-2 nucleocapsid (N1) per liter of wastewater was compared with the number of officially registered COVID-19 cases in Prague. Although the data obtained by sampling wastewater from the major Prague sewers were more consistent than those obtained from the small sewers, the correlation between wastewater-based and clinical-testing data was also good for the residential areas with more than 7,000 registered inhabitants. It was shown that monitoring SARS-CoV-2 RNA in wastewater sampled from small sewers could identify isolated occurrences of COVID-19-positive cases in local neighborhoods. This can be very valuable while tracking COVID-19 hotspots within large cities.

Investigation of the influence of mineral dust on airborne particulate matter during the COVID-19 epidemic in spring 2020 over China

A regional air quality model system (RAQMS) driven by the Weather Research and Forecasting model (WRF) is applied to investigate the distribution and evolution of mineral dust and anthropogenic aerosols over China in April 2020, when air quality was improved due to reduced human activity during the COVID-19 epidemic, whereas dust storms began to attack China and deteriorated air quality. A dust deflation model was developed and improved mineral dust prediction. Model validation demonstrated that RAQMS was able to reproduce PM₁₀, PM_2.5 and aerosol components reasonably well. China suffered from three dust events in April 2020, with the maximum hourly PM₁₀ concentrations exceeding 700 μg m^-3 in downwind cities over the North China Plain (NCP). Mineral dust dominated PM₁₀ mass (>80%) over the Gobi deserts in north and west China, while it comprised approximately 30-50% of PM₁₀ over wide areas of east China. The domain and monthly mean dust mass fractions in PM₁₀ were estimated to be 47% and 43% over the North China Plain and east China, respectively. On average, mineral dust contributed up to 22% and 21% of PM_2.5 mass over the North China Plain and east China in April 2020, respectively. Sulfate and nitrate produced by heterogeneous chemical reactions on dust surface accounted for approximately 9% and 13% of secondary inorganic aerosols (SIA) concentration over the North China Plain and east China, respectively. The results from this study demonstrated that mineral dust made an important contribution to particulate matter mass during the COVID-19 epidemic in spring 2020 over China.

Modeling and Preliminary Analysis of the Impact of Meteorological Conditions on the COVID-19 Epidemic

Since the COVID-19 epidemic outbreak at the end of 2019, many studies regarding the impact of meteorological factors on the attack have been carried out, and inconsistent conclusions have been reached, indicating the issue's complexity. To more accurately identify the effects and patterns of meteorological factors on the epidemic, we used a combination of logistic regression (LgR) and partial least squares regression (PLSR) modeling to investigate the possible effects of common meteorological factors, including air temperature, relative humidity, wind speed, and surface pressure, on the transmission of the COVID-19 epidemic. Our analysis shows that: (1) Different countries and regions show spatial heterogeneity in the number of diagnosed patients of the epidemic, but this can be roughly classified into three types: "continuous growth", "staged shock", and "finished"; (2) Air temperature is the most significant meteorological factor influencing the transmission of the COVID-19 epidemic. Except for a few areas, regional air temperature changes and the transmission of the epidemic show a significant positive correlation, i.e., an increase in air temperature is conducive to the spread of the epidemic; (3) In different countries and regions studied, wind speed, relative humidity, and surface pressure show inconsistent correlation (and significance) with the number of diagnosed cases but show some regularity.

Addressing External Shock in Urban Agglomeration: Implications From the Transmission Pattern of COVID-19 in the Beijing-Tianjin-Hebei Area

Properly addressing external shocks in urban agglomeration is critical to sustaining the complex regional system. The COVID-19 pandemic has been widely acknowledged as an unintended external shock, but the temporal and spatial transmission patterns are largely ignored. This study analyzed the temporal and spatial transmission patterns of COVID-19 at the macro, meso, and micro levels, and proposes a conceptual model for regional comprehensive risk calculation, taking the Beijing-Tianjin-Hebei (BTH) area as the focus region. Our results showed that 1) at the temporal scale, the epidemic in the BTH area experienced stages of rapid increase, gradual decrease, and stabilization, and the first wave of the epidemic was under control from 23 February 2020; 2) at the spatial scale, confirmed cases were largely distributed at the terminal of the migration network, with closely interconnected cities in the BTH area, including Beijing, Tianjin, Tangshan, and Langfang, holding the highest comprehensive epidemic risk, thus requiring special attention for epidemic prevention and control. Finally, a "two-wheels" conceptual framework was built to discuss implications for future policies for addressing external shocks. Our proposed framework consists of an isolation wheel, which involves information sharing from the holistic perspective, and a circulation wheel, which emphasizes stakeholder involvement from the individual perspective. The findings of this study provide a knowledge basis for epidemic prevention and control as well as useful implications for addressing external shocks in the future.

Designing an integrated responsive-green-cold vaccine supply chain network using Internet-of-Things: artificial intelligence-based solutions

In this paper, a new responsive-green-cold vaccine supply chain network during the COVID-19 pandemic is developed for the first time. According to the proposed network, a new multi-objective, multi-period, multi-echelon mathematical model for the distribution-allocation-location problem is designed. Another important novelty in this paper is that it considers an Internet-of-Things application in the COVID-19 condition in the suggested model to enhance the accuracy, speed, and justice of vaccine injection with existing priorities. Waste management, environmental effects, coverage demand, and delivery time of COVID-19 vaccine simultaneously are therefore considered for the first time. The LP-metric method and meta-heuristic algorithms called Gray Wolf Optimization (GWO), and Variable Neighborhood Search (VNS) algorithms are then used to solve the developed model. The other significant contribution, based on two presented meta-heuristic algorithms, is a new heuristic method called modified GWO (MGWO), and is developed for the first time to solve the model. Therefore, a set of test problems in different sizes is provided. Hence, to evaluate the proposed algorithms, assessment metrics including (1) percentage of domination, (2) the number of Pareto solutions, (3) data envelopment analysis, and (4) diversification metrics and the performance of the convergence are considered. Moreover, the Taguchi method is used to tune the algorithm's parameters. Accordingly, to illustrate the efficiency of the model developed, a real case study in Iran is suggested. Finally, the results of this research show MGO offers higher quality and better performance than other proposed algorithms based on assessment metrics, computational time, and convergence.

Lessons drawn from China and South Korea for managing COVID-19 epidemic: Insights from a comparative modeling study

We conducted a comparative study of the COVID-19 epidemic in three different settings: mainland China, the Guangdong province of China and South Korea, by formulating two disease transmission dynamics models which incorporate epidemic characteristics and setting-specific interventions, and fitting the models to multi-source data to identify initial and effective reproduction numbers and evaluate effectiveness of interventions. We estimated the initial basic reproduction number for South Korea, the Guangdong province and mainland China as 2.6 (95% confidence interval (CI): (2.5, 2.7)), 3.0 (95%CI: (2.6, 3.3)) and 3.8 (95%CI: (3.5,4.2)), respectively, given a serial interval with mean of 5 days with standard deviation of 3 days. We found that the effective reproduction number for the Guangdong province and mainland China has fallen below the threshold 1 since February 8th and 18th respectively, while the effective reproduction number for South Korea remains high until March 2nd Moreover our model-based analysis shows that the COVID-19 epidemics in South Korean is almost under control with the cumulative confirmed cases tending to be stable as of April 14th. Through sensitivity analysis, we show that a coherent and integrated approach with stringent public health interventions is the key to the success of containing the epidemic in China and especially its provinces outside its epicenter. In comparison, we find that the extremely high detection rate is the key factor determining the success in controlling the COVID-19 epidemics in South Korea. The experience of outbreak control in mainland China and South Korea should be a guiding reference for the rest of the world.