Silicon photonic chip-based biosensor for COVID-19 and flu detection with high sensitivity and specificity

Since the end of 2021, Omicron, the new variant of SARS-CoV-2, has continued to spread as the predominant strain of COVID-19. Compared to previous variants, Omicron causes milder symptoms, which are similar to symptoms of other common respiratory infections, such as flu. In this work, we develop a silicon photonic chip-based biosensor for COVID-19 and flu detection using subwavelength grating micro-ring resonator. The biosensor realizes the detection of two pathogens with high sensitivity (1.31 fg/mL) and specificity. Besides, the microfluidic channel offers a promising solution for point-of-care detection. © 2023 SPIE.

Study on population behavior under home quarantine policies of COVID-19 in China based on double-layer network evolutionary games

In the practice of COVID-19 prevention and control in China, the home quarantine policy directly connects and manages the residents, which plays a significant role in preventing the spread of the epi-demic in the community. We evaluate the effectiveness of current home quarantine policy in the actual execution process based on the evolutionary game relationship between the community and res-idents. This paper establishes a double-layer coupled complex network game model, and uses the multi-agent modeling method to study the game relationship between the community and residents in the context of home quarantine policies. The results show that initial strategy of the community with strict supervision and reasonable government reward allocation will increase the proportion of the residents complying with the quarantine rule. When 80% of the communities chose to supervise strictly at the beginning, people are more likely to follow the rules. While when the residents can only get 20% of the government's reward, the proportion of choosing to violate the quarantine rules is much higher than that when they can get 80% of the reward. Besides, the structure of small-world network and environmental noise will also affect the residents' strategy. As the probability of reconnection of the small-world network rises from 0.2 to 0.8, the proportion of residents who choose to comply with the strategy becomes much higher. When the environmental noise reaches 0.5, the ratio of residents who choose to violate the strategy is higher than the ratio of complianc. The study is helpful to provide the basis for the government to formulate the quarantine policy and propose an optimization for making effective quarantine measures. In this way, the government can adjust the parameters to make residents achieve the possible level of compliance with quarantine policies as high as possible to contain the spread of the epidemic.

Anti-Fraud Analysis during the COVID-19 Pandemic: A Global Perspective

The ongoing coronavirus disease 2019 (COVID-19) pandemic has brought unexpected economic downturns and accelerated digital transformation, leading to stronger financial fraud motives and more complicated fraud schemes. Although scholars, practitioners, and regulators have begun to focus on the new characteristics of financial fraud, a systematic and effective anti-fraud strategy during the pandemic still needs to be explored. This paper comprehensively analyzes the lessons of anti-fraud that we should learn from the COVID-19 pandemic. By exploring the complex motives and schemes of fraud, we summarize the characteristics of financial fraud activities and further analyze the regulatory challenges posed by financial fraud during the outbreak. To better cope with the fraudulent activities during the pandemic, policy proposals on how to improve the supervision of financial fraud activities are put forward. In particular, the panoramic data and graph-based techniques are powerful tools for future fraud detection.

Characteristics of skin damage among healthcare workers during COVID-19 pandemic: an epidemiological survey.

Objective: To investigate epidemiological features of skin damage among front-line healthcare workers fighting against COVID-19 pandemic. Method(s): A self-designed questionnaire was released on an online survey website "wenjuan.com", and sent to the front-line medical staff caring for patients with confirmed COVID-19 in 6 infectious disease wards of the General Hospital of Central Theater Command of PLA via WeChat from March 10th to 20th, 2020. Then, the questionnaires were collected, a database was established, and statistical analysis was performed on the incidence, types and epidemiological characteristics of skin damage among the medical staff. Result(s): A total of about 550 medical staff were surveyed, 404 questionnaires were collected, of which 391 were valid, and 303 cases had skin damage. The survey showed that females, hand cleaning frequency > 10 times per day, wearing three-level protective equipment for more than 6 hours per week were risk factors for skin damage, and frequent use of a hand cream could reduce skin problems. Among the respondents, the incidence of skin damage was significantly higher in the females (79.81%, 249/312) than in the males (38.35%, 54/79;chi2 = 4.741, P = 0.029), and higher in the groups with hand cleaning frequency of 10-20 times per day (79.73%, 118/148) and > 20 times per day (85.71%, 84/98) than in the group with hand cleaning frequency of 1-10 times per day (69.66%, 101/145;chi2 = 9.330, P = 0.009). The incidence of skin damage was significantly lower in the group wearing protective equipment for 1-5 hours per week (64.04%, 73/114) than in the groups wearing protective equipment for 6-10 hours per week (81.48%, 66/81), 11-15 hours per week (95.24%, 20/21), 16-20 hours per week (81.82%, 36/44), 21-25 hours per week (86.49%, 32/37), and > 25 hours per week (80.85%, 76/94;chi2 = 19.164, P = 0.002). Among the 391 respondents, the skin damage related to disinfection and protective equipment mainly manifested as dry skin (72.89%), desquamation (56.78%), skin pressure injury (54.48%), skin maceration (45.01%), and sensitive skin (33.50%);acne (27.11%) was the related skin disease with the highest incidence, followed by facial dermatitis (23.27%), eczematous dermatitis (21.48%), folliculitis (18.92%), dermatomycosis (11.00%), urticaria (9.21%), etc. Conclusion(s): There was a high incidence of skin damage related to protective equipment among the front-line healthcare workers fighting against COVID-19, and strengthening skin protection could markedly reduce the incidence of skin damage.Copyright © 2020 by the Chinese Medical Association.

Analysis of the Spatial Distribution and Associated Factors of the Transmission Locations of COVID-19 in the First Four Waves in Hong Kong

Understanding the space–time pattern of the transmission locations of COVID-19, as well as the relationship between the pattern, socioeconomic status, and environmental factors, is important for pandemic prevention. Most existing research mainly analyzes the locations resided in or visited by COVID-19 cases, while few studies have been undertaken on the space–time pattern of the locations at which the transmissions took place and its associated influencing factors. To fill this gap, this study focuses on the space–time distribution patterns of COVID-19 transmission locations and the association between such patterns and urban factors. With Hong Kong as the study area, transmission chains of the four waves of COVID-19 outbreak in Hong Kong during the time period of January 2020 to June 2021 were reconstructed from the collected case information, and then the locations of COVID-19 transmission were inferred from the transmission chains. Statistically significant clusters of COVID-19 transmission locations at the level of tertiary planning units (TPUs) were detected and compared among different waves of COVID-19 outbreak. The high-risk areas and the associated influencing factors of different waves were also investigated. The results indicate that COVID-19 transmission began with the Hong Kong Island, further moved northward towards the New Territories, and finally shifted to the south Hong Kong Island, and the transmission population shows a difference between residential locations and non-residential locations. The research results can provide health authorities and policy-makers with useful information for pandemic prevention, as well as serve as a guide to the public in the avoidance of activities and places with a high risk of contagion. © 2023 by the authors.

Research on fatigue identification methods based on low-load wearable ECG monitoring devices

The identification of fatigue in personal workers in particular environments can be achieved through early warning techniques. In order to prevent excessive fatigue of medical workers staying in infected areas in the early phase of the coronavirus disease pandemic, a system of low-load wearable electrocardiogram (ECG) devices was used as intelligent acquisition terminals to perform a continuous measurement ECG collection. While machine learning (ML) algorithms and heart rate variability (HRV) offer the promise of fatigue detection for many, there is a demand for ever-increasing reliability in this area, especially in real-life activities. This study proposes a random forest-based classification ML model to identify the four categories of fatigue levels in frontline medical workers using HRV. Based on the wavelet transform in ECG signal processing, stationary wavelet transform was applied to eliminate the main perturbation of ECG in the motion state. Feature selection was performed using ReliefF weighting analysis in combination with redundancy analysis to optimize modeling accuracy. The experimental results of the overall fatigue identification achieved an accuracy of 97.9% with an AUC value of 0.99. With the four-category identification model, the accuracy is 85.6%. These results proved that fatigue analysis based on low-load wearable ECG monitoring at low exertion can accurately determine the level of fatigue of caregivers and provide further ideas for researchers working on fatigue identification in special environments. © 2023 Author(s).

Clinical characteristics of patients with diabetes mellitus complicated with COVID-19.

Objective: To study the clinical characteristics of diabetes mellitus with Coronavirus disease 2019 (COVID-19) and explore the possible mechanism of diabetes predisposition. Method(s): A single center, retrospective and observational study was used to collect 48 inpatients diagnosed with COVID-19 who were admitted to the first ward of the third department of infection, Raytheon hospital, Wuhan from February 23, 2020 to March 30, 2020. Demographic data, symptoms, laboratory tests, comorbidities, treatments and clinical outcomes have been collected. The patients were divided into non-diabetic group and diabetic group according to the combination of diabetes. The clinical data and laboratory test results of the two groups were observed, and the t test, non-parametric test and Chi square test were used for comparison. Result(s): All the 5 patients with COVID-19 diabetes mellitus had fever and respiratory symptoms, chest CT was consistent with typical COVID-19 imaging features, and novel coronavirus nucleic acid test results were positive. There were no statistically significant differences in age, gender composition, co-existing diseases, clinical symptoms, clinical typing, disease course and treatment plan between the diabetic group and the non-diabetic group (P>0.05).There was a statistically significant difference in fasting blood glucose between the non-diabetic group and the diabetic group (P<0.05).The difference of fasting blood glucose at discharge from the diabetes group compared with that at admission was also statistically significant (P<0.05).There was no statistically significant difference between the two groups in other laboratory examination indexes (P>0.05). Conclusion(s): COVID-19 patients with diabetes are mainly manifested by fever and respiratory symptoms.Chest CT shows typical COVID-19 imaging features.Copyright © 2020 by the Chinese Medical Association.

Inegalites en vaccination contre la COVID-19 au Canada en 2021.

Contexte: Pour mesurer les inegalites dans la vaccination contre la COVID-19 chez les adultes au Canada, nous avons analyse les donnees de l'Enquete sur la sante dans les collectivites canadiennes de juin a septembre 2021 et identifie les facteurs sociodemographiques associes a la non-vaccination et a l'intention de ne pas se faire vacciner. Methodes: Les donnees proviennent d'une enquete annuelle transversale et representative a l'echelle nationale menee par Statistique Canada. Des modeles de regression logistique ajustes ont ete utilises pour mesurer les associations entre, d'une part, des variables sociodemographiques et liees a la sante (region, age, sexe, scolarite, statut autochtone, statut de minorite visible, etat de sante percu et acces regulier a un professionnel de la sante) et d'autre part la non-vaccination et l'intention de ne pas se faire vacciner. Resultats: La non-vaccination etait associee a un faible niveau de scolarite (RCa jusqu'a 3,5), a la presence d'enfants de moins de 12 ans dans le menage (RCa 1,6), a l'absence d'acces regulier a un professionnel de la sante (RCa 1,6) et a une mauvaise perception de sa propre sante (RCa 1,8). Seuls 5 % des adultes n'avaient pas l'intention de se faire vacciner. L'intention de ne pas se faire vacciner etait associe au jeune age (RCa jusqu'a 4,0), a une scolarite moindre (RCa jusqu'a 3,8), a la non-appartenance a une minorite visible (RCa 3,0), a la presence d'enfants de moins de 12 ans (RCa 1,8) et a une mauvaise perception de sa propre sante (RCa 2,0). Discussion/Conclusion: Des disparites ont ete observees dans la couverture vaccinale et l'intention de ne pas se faire vacciner. Les strategies de promotion de la vaccination devraient tenir compte de ces disparites. Declaration de liens d'interets: Les auteurs declarent ne pas avoir de liens d'interets.Copyright © 2022

COVIDware: Designing Interactive Everyday Things as Tangible Homeware for Social Isolation

This paper describes our collaborative journey of creating everyday interactive artefacts to help us think, reflect, and live through self-isolation. Through a co-design approach, we designed interactive homeware objects (that we collectively refer to as ‘COVIDware') to address the challenges of isolation during the pandemic. Five artefacts were developed by self-isolated designers as interactive art installations. We discuss how each creator reflected on her design concept, process, and encounter through concepts of critical making, speculation, and engagement via in-the-isolated-wild deployments. By empowering early researchers/enthusiasts to design ‘with' smart-materials, and off-the-shelf items, we reflect on how these homey interfaces can enhance people's wellbeing beyond screen-based interactions. Despite not collaborating in the making process, our findings from the designer's making process show how all the designed artefacts shared attributes of biophilic design, imperfection, and unconventional interactions with the overarching goal of promoting wellbeing, and meaningful connection with nature, self, and others. © 2022,Interaction Design and Architecture(s). All Rights Reserved.

The situation and enlightenment of transnational oil and gas exploration

Affected by the global COVID-19 and middle/low oil prices, the exploration investment was running at a low level and the exploration workload fell in 2021. However, oil companies focused on frontier fields and key exploration and development areas. By deepening geological understanding and improving trap identification ability, the success rate of exploration was continuously improved. Great discoveries were successively obtained in offshore exploration, especially in deep water and ultra-deep water areas, and transnational large and medium-sized oil and gas fields discovered by major international oil companies were mainly located in "one ocean, one bay and one sea” (both sides of the Atlantic Ocean, the Gulf of Mexico and the South Caspian Sea). The analysis of typical oil and gas fields in deep water and ultra-deep water areas indicates characteristics in three aspects. Firstly, by paying close attention to the oil and gas rich basins, a series of subsalt oil and gas discoveries were made in Brazil after eight years' exploration. Secondly, by accumulating knowledge and strategically reexploring, Eni successively discovered oil fields in Cote d'Ivoire Basin. Thirdly, by developing the existing oil and gas fields and then expanding the peripheral areas, bp discovered large gas field once again in the South Caspian Sea. The practice of the major international oil companies in implementing transnational petroleum exploration in deep water and ultra-deep water areas enables to obtain three enlightenments. First, layout in advance, seize the opportunity of favorable exploration zones, and flexibly acquire and relinquish blocks. Second, strategically follow other companies, constantly accumulate experience and technology to steadily improve strength. Third, independently conduct exploration, master the key and core technologies to achieve benefits in exploration. Chinese oil companies should seize all opportunities to actively acquire favorable exploration blocks, so as to form effective resource reserves, and realize the leap from "going global” to "going up” through "one transformation and three strengthening”. Copyright © 2022, Petroleum Industry Press, PetroChina. All rights reserved.

Updated Key Points Interpretation of Global Strategy for the Diagnosis，Management，and Prevention of Chronic Obstructive Pulmonary Disease （2023 Report）

Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease (2023 Report) (GOLD 2023) maintains the basic framework of GOLD 2022, but with major revisions in the definition, assessment, initial therapy and follow-up management of chronic obstructive lung disease (COPD) as follow: (1) Chapter 1: The definition and overview section was rewritten to propose a new definition of COPD, incorporating new background information, therapeutic strategies and classifications for COPD, with the addition of content on chronic bronchitis;(2) Chapter 2: Content on screening and case-finding of COPD has been included, the ABCD assessment tool has been revised to the ABE assessment tool (no further grouping of high-risk population of acute exacerbation of COPD based on symptom levels), information on imaging and computed tomography scans (CT) has been included in the diagnosis and assessment section;(3) Chapter 3: Recommendations for Streptococcus pneumoniae vaccination have been updated, information on therapeutic interventions to reduce COPD mortality has been included, issues related to inhalation delivery have been updated, content on inhaled medications adherence and remote rehabilitation has been included, information on interventional and surgical therapies of COPD has been expanded in the prevention and maintenance treatment section;(4) Chapter 4: Information on the selection of inhalation devices has been included, information on initial drug therapy and follow-up drug therapy has been updated in the management of stable COPD section;(5) Chapter 5: A new definition of and set of acute exacerbation of COPD assessment parameters have been proposed, information on differential diagnoses of acute exacerbation of COPD has been expanded in the acute exacerbation of COPD section management;(6) Chapter 6 and 7: Updating content on COPD and complications (Chapter 6), COPD (Chapter 7) and COVID-19 based on the latest evidence. The above updates will be an important guide to the clinical management of COPD. © 2023 Chinese General Practice. All rights reserved.

Modified Coronavirus Herd Immunity Optimizer for Permutation Scheduling Problems

The permutation flow shop scheduling problem (PFSSP) is well-applied in the industry, which is confirmed to be an NP-Hard optimization problem, and the objective is to find the minimum completion time (makespan). A modified coronavirus herd immunity optimizer (CHIO) with a modified solution update is suggested in this work. Meanwhile, the simulated annealing strategy is used on the updating herd immunity population to prevent trapping on local optima, and an adjusted state mechanism is involved to prevent fast state change/ convergence. Nine instances of different problem scales on the FPSSP dataset of Taillard were tested. The experimental results show that the proposed method can find the optimal solutions for the tested instances, with ARPDs no more than 0.1, indicating that the proposed method can effectively and stably solve the PFSSP. © 2022 IEEE.

Epidemiology of Neurological and Cardiac Complications of COVID-19 among Ontario Visible Minorities: A Retrospective Study of Chinese and South Asian Canadians

Background: This is a population-based retrospective study of neurological and cardiac complications of COVID-19 among Ontario visible minorities: Chinese and South Asian Canadians Methods: From January 1, 2020 to September 30, 2020, using the last name algorithm, rates and types of cardiac and neurological complication of these two cohorts along with the general population in Ontario with COVID-19 were analysed by Institue of Clinical Evaluative Sciences. Results: Preliminary results show that Chinese-Canadians (N= 1,186) with COVID-19 are older with a mean age of 50.74 years old compared to general population (N= 42,547) of 47.57 years old (P< .001), while South Asians (N= 3,459) have a younger mean age of 42.08 years old (P< .001). Total cardiac and neurological complication rates, hospitalization rates and ICU admission rates are all higher for Chinese-Canadians while they are lower in South Asians and all achieving statistical significance (P < .001). Overall mortality rate is significantly higher for Chinese-Canadians at 8.1% vs 5.0% general population (P < .001). Conclusions: Chinese-Canadians with COVID-19 in Ontario were much older and have higher cardiac and neurological complication rates and overall mortality rate than the general population. These data have significant implications for proper prevention and appropriate management for these vulnerble elderly Chinese-Canadians.

The Politicization of COVID-19 Origin Stories: Insights from a Cross-Sectional Survey in China

The search for the origins of COVID-19 has yielded no conclusive evidence. In the face of this uncertainty, other social and political factors can influence perceptions of virus origins, which in turn can influence policy formation and global efforts to combat future pandemics. Vastly different COVID-19 origin stories may circulate both within the same country but also between different countries. This article examines COVID-19 origins debates as they circulate in China, drawing from a 974-respondent survey conducted in mainland China. Our results show that within China there is a strong belief that COVID-19 originated outside the country, either in the United States or Europe. This contrasts with mainstream media coverage in the United State and Europe, which generally holds that the virus most likely originated in China. Given such global dissonance, moving forward with pandemic prevention reforms is challenging. Yet, even in the face of such diverse beliefs, building support for reform is still possible. As the search for COVID-19 continues, policy reform can be pursued across a plurality of domains, including wet markets, the wildlife trade, cold-chain products, and gain-of-function virology research, all in the interest of preventing the next global pandemic. © 2023 by the authors.

Clinical characteristics of patients with diabetes mellitus complicated with COVID-19.

Objective: To study the clinical characteristics of diabetes mellitus with Coronavirus disease 2019 (COVID-19) and explore the possible mechanism of diabetes predisposition. Method(s): A single center, retrospective and observational study was used to collect 48 inpatients diagnosed with COVID-19 who were admitted to the first ward of the third department of infection, Raytheon hospital, Wuhan from February 23, 2020 to March 30, 2020. Demographic data, symptoms, laboratory tests, comorbidities, treatments and clinical outcomes have been collected. The patients were divided into non-diabetic group and diabetic group according to the combination of diabetes. The clinical data and laboratory test results of the two groups were observed, and the t test, non-parametric test and Chi square test were used for comparison. Result(s): All the 5 patients with COVID-19 diabetes mellitus had fever and respiratory symptoms, chest CT was consistent with typical COVID-19 imaging features, and novel coronavirus nucleic acid test results were positive. There were no statistically significant differences in age, gender composition, co-existing diseases, clinical symptoms, clinical typing, disease course and treatment plan between the diabetic group and the non-diabetic group (P>0.05).There was a statistically significant difference in fasting blood glucose between the non-diabetic group and the diabetic group (P<0.05).The difference of fasting blood glucose at discharge from the diabetes group compared with that at admission was also statistically significant (P<0.05).There was no statistically significant difference between the two groups in other laboratory examination indexes (P>0.05). Conclusion(s): COVID-19 patients with diabetes are mainly manifested by fever and respiratory symptoms.Chest CT shows typical COVID-19 imaging features.Copyright © 2020 by the Chinese Medical Association.

Optimization of SARS-CoV-2 spike protein receptor binding domain expression in Pichia pastoris and evaluation of its immunogenicity.

Objective To effectively express the receptor binding domain (RBD) of SARS-CoV-2 spike protein in Pichia pastoris and to evaluate its immunogenicity. Methods The gene encoding the RBD protein was synthesized and cloned into the pPICZalphaA plasmid. After linearization, the plasmid was transferred and integrated into the genome of Pichia pastoris. The expressed RBD protein in culture supernatant was analyzed by Western blot and Biolayer interferometry. After screening, a single clone expressing the RBD protein was selected. The high-level expression of RBD protein was achieved by optimizing the fermentation process, including the salt concentration adjusting of the medium and induction condition optimization (pH, temperature and duration) . The immunogenicity of the expressed RBD protein was evaluated in a mouse model. Results A single clone with a high expression level of RBD protein was obtained and named RBD-X33. The expression level of RBD protein in the fermentation supernatant reached up to 240 mg / L after optimization of the induction condition (HBSM medium, pH = 6. 5 +/- 0. 3, 22 and 120 h) . In the mouse experiment, the recombinant RBD protein was formulated with Alum + CpG dual adjuvant and injected into mice. The binding IgG antibody levels were up to 2. 7 x 106 tested by ELISA and the neutralizing antibody levels were up to 726. 8 tested by live virus neutralizing antibody assay (prototype) . Conclusions The RBD protein could be efficiently expressed in Pichia pastoris and induce stronger immune response in animals. This study suggested that the recombinant SARS-CoV-2 RBD protein expressed in Pichia pastoris could serve as a candidate antigen in the development of SARS-CoV-2 vaccine.Copyright © 2022 Society of Microbiology and Immunology. All rights reserved.

Impact of COVID-19 Pandemic on the Frequency of Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Background Respiratory virus infection is an important trigger of acute exacerbation of chronic obstructive pulmonary disease（AECOPD）. China has adopted a series of containment measures assisting to curb COVID-19 transmission since the outbreak of the pandemic. Several studies showed a decrease in hospitalizations for AECOPD during the COVID-19 pandemic. However，there has been a relative lack of studies investigating the effects of preventive measures on the frequency and severity of exacerbations. Objective To explore the impact of the COVID-19 pandemic on the frequency of AECOPD with or without medical attention. Methods The subjects were from a prospective COPD cohort study conducted in the First Affiliated Hospital of Guangzhou Medical University，which began recruiting patients in early 2016，with visits every 3 months to collect demographic and clinical data，including those who were followed up during June to August 2017（group 1），June to August 2018（group 2），June to August 2019 （group 3），and June to August 2020（group 4）. Basic clinical data （including the frequency of AECOPD，sex，age，symptom score and so on） were collected from group 1 from October 2016 to May 2017，group 2 from October 2017 to May 2018，group 3 from October 2018 to May 2019，and group 4 from October 2019 to May 2020（during which the periods from October 2019 to January 2020，and from February to May 2020 were defined as preCOVID-19 period，and post-COVID-19 period，respectively）. The frequency of AECOPD during October to May next year in group 4 was compared with that of the other three groups. The changes in the frequency of AECOPD between pre- and postCOVID-19 periods were analyzed. Results There were 162 patients in group 1，157 in group 2，167 in group 3，and 159 in group 4. Group 1 had a higher frequency of AECOPD in February to May than in October to January next year（P=0.013），so did group 2（P=0.016）. In contrast，group 4 had a higher frequency of AECOPD in October to January next year than in February to May（P=0.001）. The frequency of AECOPD during October to December in group 4 was similar to that of the other three groups（P>0.05）. But the frequency of AECOPD from February to April in group 4 was lower than that in groups 1-3 （P<0.05）. There was no significant difference in the monthly frequency of AECOPD without medical attention in group 4 compared with that of groups 1-3（P>0.05）. The frequency of AECOPD with medical attention from October to December in group 4 was similar to that of groups 1-3（P>0.05）. but it from February to April in group 4 was lower than that in groups 1-3（P<0.05）. Conclusion Prevention and control measures targeting COVID-19 may be contributive to reducing the frequency of AECOPD. It is suggested that COPD patients should reduce gathering activities，maintain social distance，wear masks when going out，and wash hands frequently even after the COVID-19. © 2023 Chinese General Practice. All rights reserved.

A Novel COVID-19 Image Classification Method Based on the Improved Residual Network

In recent years, chest X-ray (CXR) imaging has become one of the significant tools to assist in the diagnosis and treatment of novel coronavirus pneumonia. However, CXR images have complex-shaped and changing lesion areas, which makes it difficult to identify novel coronavirus pneumonia from the images. To address this problem, a new deep learning network model (BoT-ViTNet) for automatic classification is designed in this study, which is constructed on the basis of ResNet50. First, we introduce multi-headed self-attention (MSA) to the last Bottleneck block of the first three stages in the ResNet50 to enhance the ability to model global information. Then, to further enhance the feature expression performance and the correlation between features, the TRT-ViT blocks, consisting of Transformer and Bottleneck, are used in the final stage of ResNet50, which improves the recognition of complex lesion regions in CXR images. Finally, the extracted features are delivered to the global average pooling layer for global spatial information integration in a concatenated way and used for classification. Experiments conducted on the COVID-19 Radiography database show that the classification accuracy, precision, sensitivity, specificity, and F1-score of the BoT-ViTNet model is 98.91%, 97.80%, 98.76%, 99.13%, and 98.27%, respectively, which outperforms other classification models. The experimental results show that our model can classify CXR images better. © 2022 by the authors.

Comparing the performance between static and dynamic populations in COVID-19 hotspot prediction

Objectives: This study aimed to set up the prediction model of COVID-19 hotspot areas by using the census data and human mobility from telecommunication data in Taipei and New Taipei City. The comparison between their accuracy and limitations can provide the relevant insights for future epidemic control. Methods: The spatio-temporal resolution is fixed at the village level in two cities in May 2021. The static and dynamic data are used to construct the mobility network. The former applies gravity model to mimic human flow, and the latter uses telecommunication data as the measure of mobility. We propose the footprints similarity by structural equivalence of spatial networks and integrate it with the number of confirmed cases for computing the risk level of the villages. The performance of the models is evaluated using ROC curves and logistic regression under different thresholds for the confirmed cases. Results: The mobility derived from the telecommunication data provided better prediction performance than that from the census data;they have an average AUC of 0.75 and 0.69, respectively. Besides, the telecommunication data had a tendency to identify a further village as high-risk zone compared to the gravity model. According to the results of logistic regression, the odds ratio (OR) of exceeding the cases' threshold estimated from the telecommunication data is 1.45 on average, while the one estimated from the census data is 1.10. Conclusions: Telecommunication data can be beneficial in identifying the potential high-risk areas and enhancing situational awareness in advance. © 2022, Taiwan Public Health Association. All rights reserved.

Impact of COVID-19 Pandemic on the Frequency of Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Background Respiratory virus infection is an important trigger of acute exacerbation of chronic obstructive pulmonary disease（AECOPD）. China has adopted a series of containment measures assisting to curb COVID-19 transmission since the outbreak of the pandemic. Several studies showed a decrease in hospitalizations for AECOPD during the COVID-19 pandemic. However，there has been a relative lack of studies investigating the effects of preventive measures on the frequency and severity of exacerbations. Objective To explore the impact of the COVID-19 pandemic on the frequency of AECOPD with or without medical attention. Methods The subjects were from a prospective COPD cohort study conducted in the First Affiliated Hospital of Guangzhou Medical University，which began recruiting patients in early 2016，with visits every 3 months to collect demographic and clinical data，including those who were followed up during June to August 2017（group 1），June to August 2018（group 2），June to August 2019 （group 3），and June to August 2020（group 4）. Basic clinical data （including the frequency of AECOPD，sex，age，symptom score and so on） were collected from group 1 from October 2016 to May 2017，group 2 from October 2017 to May 2018，group 3 from October 2018 to May 2019，and group 4 from October 2019 to May 2020（during which the periods from October 2019 to January 2020，and from February to May 2020 were defined as preCOVID-19 period，and post-COVID-19 period，respectively）. The frequency of AECOPD during October to May next year in group 4 was compared with that of the other three groups. The changes in the frequency of AECOPD between pre- and postCOVID-19 periods were analyzed. Results There were 162 patients in group 1，157 in group 2，167 in group 3，and 159 in group 4. Group 1 had a higher frequency of AECOPD in February to May than in October to January next year（P=0.013），so did group 2（P=0.016）. In contrast，group 4 had a higher frequency of AECOPD in October to January next year than in February to May（P=0.001）. The frequency of AECOPD during October to December in group 4 was similar to that of the other three groups（P>0.05）. But the frequency of AECOPD from February to April in group 4 was lower than that in groups 1-3 （P<0.05）. There was no significant difference in the monthly frequency of AECOPD without medical attention in group 4 compared with that of groups 1-3（P>0.05）. The frequency of AECOPD with medical attention from October to December in group 4 was similar to that of groups 1-3（P>0.05）. but it from February to April in group 4 was lower than that in groups 1-3（P<0.05）. Conclusion Prevention and control measures targeting COVID-19 may be contributive to reducing the frequency of AECOPD. It is suggested that COPD patients should reduce gathering activities，maintain social distance，wear masks when going out，and wash hands frequently even after the COVID-19. © 2023 Chinese General Practice. All rights reserved.