Detecting COVID-19 spreading phases with time series analysis

Piecewise linear regression (PLR) method is applied to study cumulative cases of COVID-19 evolving everyday in England up to 6th February 2022 just before travel restrictions are removed and people started not to get tested anymore in the UK and factors e.g. the lockdowns behind the spread COVID-19 are also investigated. It is clear that different periods exhibit distinct patterns depending on variants and government-imposed restriction. Therefore, the effectiveness of lockdown measures is evaluated by comparing the rate of increase after a certain period (delay effect of measures) and that of time before as well as how new variants take over as a dominant variant. In addition, autoregression function is studied to show strong effect of cases in the past on today's cases since the disease is highly infectious. Most of work is carried out thorough python built-in libraries such as pandas for preprocessing data and matplotlib which allows us to gain more insight and better visualization into the real scenario. Visualization is conducted by Geoda showing the regional level of infections. © 2023 SPIE.

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

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

AI Based Directory Discovery Attack and Prevention of the Medical Systems

The medical system has been targeted by the cyber attackers, who aim to bring down the health security critical infrastructure. This research is motivated by the recent cyber-attacks happened during COVID 19 pandemics which resulted in the compromise of the diagnosis results. This study was carried to demonstrate how the medical systems can be penetrated using AI-based Directory Discovery Attack and present security solutions to counteract such attacks. We then followed the NIST (National Institute of Standards and Technology) ethical hacking methodology to launch the AI-based Directory Discovery Attack. We were able to successfully penetrate the system and gain access to the core of the medical directories. We then proposed a series of security solutions to prevent such cyber-attacks. © 2022 Creative Commons.

A Study On Security and Privacy Risks of Self-Disclosure On Social Networking Sites During COVID-19 Pandemic

Social networking sites (SNSs) contain a large amount of information that has been self-disclosed by users around the world because it provides a platform for millions of users to express their feelings, emotions, and even deepest thoughts. Some of these information are sensitive and private and can be used by hackers to launch social engineering attacks against the user or the company the user works for. Due to the physical restrictions imposed by the COVID-19 pandemic, more people turned to social media to stay connected with each other and they spent more time on social media and disclosed much more information than the pre-COVID pandemic. The objective of this research is to study the potential security risks and privacy concerns brought by the disclosed information on SNSs during the COVID-19 pandemic. We developed an automated tool to collect and analyze publicly accessible data from Twitter API using some personal keywords such as birthday, anniversary, mental health, suicide etc. to investigate the impact of the COVID-19 pandemic on the disclosed sensitive information. © 2022 IEEE.

A coagulopathic conundrum of COVID-19

We present a case of an elderly male who presented to the hospital with a worsening cough and shortness of breath. Previous outpatient COVID-19 polymerase chain reaction test was negative, and the patient's symptoms failed to improve despite one-week course of antibiotics. He presented to the hospital a few days later with worsening symptoms and a positive COVID-19 polymerase chain reaction test at this time. Patient was febrile, tachycardic, hypertensive, and was admitted to the intensive care unit due to desaturation on room air ultimately leading to intubation. CBC with differential showed evidence of thrombocytopenia, elevated INR/D-Dimer/fibrin split products/inflammatory markers, as well as decreased fibrinogen. He was treated for COVID-19 pneumonia and given platelets/cryoprecipitate/Vit K for suspected diffuse intravascular coagulation. © 2023, University of Toronto. 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.

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.

Taking a Language Detour: How International Migrants Speaking a Minority Language Seek COVID-Related Information in Their Host Countries

Information seeking is crucial for people's self-care and wellbeing in times of public crises. Extensive research has investigated empirical understandings as well as technical solutions to facilitate information seeking by domestic citizens of affected regions. However, limited knowledge is established to support international migrants who need to survive a crisis in their host countries. The current paper presents an interview study with two cohorts of Chinese migrants living in Japan (N=14) and the United States (N=14). Participants reflected on their information seeking experiences during the COVID pandemic. The reflection was supplemented by two weeks of self-tracking where participants maintained records of their COVID-related information seeking practice. Our data indicated that participants often took language detours, or visits to Mandarin resources for information about the COVID outbreak in their host countries. They also made strategic use of the Mandarin information to perform selective reading, cross-checking, and contextualized interpretation of COVID-related information in Japanese or English. While such practices enhanced participants' perceived effectiveness of COVID-related information gathering and sensemaking, they disadvantaged people through sometimes incognizant ways. Further, participants lacked the awareness or preference to review migrant-oriented information that was issued by the host country's public authorities despite its availability. Building upon these findings, we discussed solutions to improve international migrants' COVID-related information seeking in their non-native language and cultural environment. We advocated inclusive crisis infrastructures that would engage people with diverse levels of local language fluency, information literacy, and experience in leveraging public services. © 2022 ACM.

Efficacy and Safety of Ixekizumab in Chinese Patients with Moderate-to-Severe Plaque Psoriasis: 60-Week Results from a Phase 3 Study

Objective: Ixekizumab is a high-affinity monoclonal antibody that selectively targets interleukin-17A and is approved for treating moderate-to-severe psoriasis. This phase 3, multicenter, randomized, double-blind, placebo-controlled trial (NCT03364309;registered December 6, 2017) evaluated the safety and efficacy of ixekizumab in Chinese patients with moderate-to-severe psoriasis. Method(s): 438 patients were randomized 2:2:1 to 80 mg ixekizumab every 2 weeks (IXE Q2W, n = 176), 80 mg ixekizumab every 4 weeks (IXE Q4W, n = 174), or placebo (n = 88). Efficacy was assessed by evaluating the static Physician's Global Assessment score of 0 or 1 (sPGA [0,1]) and Psoriasis Area and Severity Index (PASI) 75/90/100 responses, and nonresponder imputation was used for handling missing data. The safety profile was evaluated by assessing treatment emergent adverse events (AEs) and serious AEs. Result(s): At week 12, the sPGA (0,1) response rates were 3.4%, 79.9%, and 86.4% in the placebo, IXE Q4W, and IXE Q2W groups, respectively. The PASI 75/90/100 response rates were 8.0%/2.3%/0.0%, 87.4%/75.9%/29.3%, and 93.8%/82.4%/33.0% in the placebo, IXE Q4W, and IXE Q2W groups, respectively. Ixekizumab led to rapid PASI 50 responses, as early as week 1, whereas PASI 75 and sPGA (0,1) responses were observed from week 2. sPGA (0,1) and sPGA (0) responses were maintained through week 60 in a higher proportion of patients receiving IXE Q4W vs. placebo. The safety profile was consistent with previous studies of ixekizumab in psoriasis. Conclusion(s): Ixekizumab showed a rapid onset of action and high efficacy that was maintained through 60 weeks and was well tolerated with no unexpected AEs, in Chinese patients with moderate-to-severe plaque psoriasis. Copyright © 2022 International Journal of Dermatology and Venereology. All right reserved.

Risk Factors for Severity and Mortality in Adult Patients Confirmed with COVID-19 in Sierra Leone: A Retrospective Study

Background:The coronavirus disease 2019 (COVID-19) is a highly infectious respiratory disease. There is no recommended antiviral treatment approved for COVID-19 in Sierra Leone, and supportive care and protection of vital organ function are performed for the patients. This study summarized the clinical characteristics, drug treatments, and risk factors for the severity and prognosis of COVID-19 in Sierra Leone to provide evidence for the treatment of COVID-19.Methods:Data of 180 adult COVID-19 patients from the 34th Military Hospital in Freetown Sierra Leone between March 31, 2020 and August 11, 2020 were retrospectively collected. Patients with severe and critically ill are classified in the severe group, while patients that presented asymptomatic, mild, and moderate disease were grouped in the non-severe group. The clinical and laboratory information was retrospectively collected to assess the risk factors and treatment strategies for severe COVID-19. Demographic information, travel history, clinical symptoms and signs, laboratory detection results, chest examination findings, therapeutics, and clinical outcomes were collected from each case file. Multivariate logistic analysis was adopted to identify the risk factors for deaths. Additionally, the clinical efficacy of dexamethasone treatment was investigated.Results:Seventy-six (42.22%) cases were confirmed with severe COVID-19, while 104 patients (57.78%) were divided into the non-severe group. Fever (56.67%, 102/180) and cough (50.00%, 90/180) were the common symptoms of COVID-19. The death rate was 18.89% (34/180), and severe pneumonia (44.12%, 15/34) and septic shock (23.53%, 8/34) represented the leading reasons for deaths. The older age population, a combination of hypertension and diabetes, the presence of pneumonia, and high levels of inflammatory markers were significantly associated with severity of COVID-19 development (P < 0.05 for all). Altered level of consciousness [odds ratio (OR) = 56.574, 95% confidence interval (CI) 5.645-566.940, P = 0.001], high levels of neutrophils (OR = 1.341, 95%CI 1.109-1.621, P = 0.002) and C-reactive protein (CRP) (OR = 1.014, 95%CI 1.003-1.025, P = 0.016) might be indicators for COVID-19 deaths. Dexamethasone treatment could reduce mortality [30.36% (17/56) vs. 50.00% (10/20)] among severe COVID-19 cases, but the results were not statistically significant (P > 0.05).Conclusions:The development and prognosis of COVID-19 may be significantly correlated with consciousness status, and the levels of neutrophils and CRP. © 2022 Journal of Bone and Joint Surgery Inc.. All rights reserved.

Characterization of Specific Humoral Immunity in Asymptomatic SARS-CoV-2 Infection

The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in December 2019 caused a huge blow to both global public health and global economy. At the early stage of the coronavirus disease 2019 (COVID-19) epidemic, asymptomatic individuals with SARS-CoV-2 infection were ignored, without appropriate identification and isolation. However, asymptomatic individuals proved to comprise a high proportion of all SARS-CoV-2-infected individuals, which greatly contributed to the rapid and wide spread of this disease. In this review, we summarize the latest advances in epidemiological characteristics, diagnostic assessment methods, factors related to the establishment of SARS-CoV-2 asymptomatic infection, as well as humoral immune features after SARS-CoV-2 infection or vaccination in asymptomatic individuals, which would contribute to effective control of ongoing COVID-19 epidemic. © 2023 American Society of Clinical Oncology.

Changes of COVID-19 Pandemic to the Future Boarding Process of Airlines

Aviation is a significant field, especially in Hong Kong with Hong Kong International Airport (HKIA) being one of the largest global transportation hubs. However, in the past years, the COVID-19 pandemic struck and significantly influenced the entire industry. As a result, the HKIA put forth an automation program with an emphasis on safety and efficiency. This paper, therefore, explores the specific process of boarding within the air traveling process due to its high susceptibility to health safety risks, utilizing the methodology of building an agent-based mathematical model and running computer simulations to find the optimal boarding strategy to be applied by Low-Cost Carriers in HKIA under the New Normal to practically achieve efficiency and safety. Throughout modeling, factors such as luggage and carry-ons, walking, seat interference, and disobedience are considered. The proportion of carry-ons stowed and luggage is also considered in further sensitivity analyses. The model is also applicable in the reverse process of disembarking a plane and under special circumstances of COVID-19 capacity limitations. The optimal method of boarding was to be found as the Maximized Corridor Usage (MCU) method. However, the practicality of a boarding method is also a large concern. Hence, the paper also incorporated a practicality factor, considering the simplicity and organization of various boarding methods, and finally concluding the MCU+2 method which boards the passengers in the window and middle seats before aisle seats as the most practically efficient and safe boarding method. © 2022 IEEE.

[Chest imaging-based artificial intelligence in the diagnosis of coronavirus disease 2019 and prospects for future research].

Artificial intelligence (AI) has been applied increasingly in the medical field during the past 5 years. Within respiratory medicine, chest imaging AI is one of the relevant hotspots, commonly trained to identify pulmonary nodules/lung tumors, tuberculosis, pneumonia, interstitial lung disease, chronic obstructive pulmonary disease, pulmonary embolism and other pathologies. Due to the non-specific clinical manifestations and the low detection rate of pathogens, precise diagnosis and treatment of pneumonia remain challengeable. Since the outbreak of coronavirus disease 2019 (COVID-19), chest imaging AI has demonstrated its clinical value in accurate diagnosis and quantitative measurements of COVID-19. Moreover, an AI system can assist the clinicians to identify the high-risk COVID-19 patients who warrant close monitoring and timely intervention. However, there are still some limitations in the existing studies, such as small sample size, lack of multi-modal assessment of the AI model, and rough classification of pneumonia. Therefore, some suggestions for future research were put forward in this paper. Most of all, more attention should be paid to the collection of high-quality datasets, standardization of image annotation, technology innovation, algorithm optimization and model verification. Besides, the application of imaging AI on other types of pneumonia including viral pneumonia, bacterial pneumonia and pneumomycosis deserves further study. In conclusion, chest imaging AI is expected to play a vital role in decision-making for pneumonia in the future.

Masked Facial Region Recognition Using Human Pose Estimation and Broad Learning System

COVID-19 and its variants have been posing a large risk to people around the world since the outbreak of the disease. Many techniques like AI are explored to help combat epidemics. People are required or forced to wear a mask to fight against COVID-19 epidemics worldwide. It brings new challenges to the task of masked facial region recognition. When facial regions are occluded by masks, it will result in some failures of face detection algorithms. In this paper, we propose a method to recognize masked faces. It mainly includes three parts. Firstly, the human pose is estimated to produce a series of key points. It is implemented by OpenPose. Secondly, a key-points location strategy is designed to capture the masked facial regions. It can locate the positions of faces accurately. Thirdly, the broad learning system, which is also an incremental learning algorithm, is employed to recognize the classes of candidate regions. Experiments conducted on some datasets shed light on the effectiveness of the proposed method. © 2022 SPIE.

Immune inhibitory receptor LILRB2 enhances SARS-CoV-2 spike protein-mediated immune inflammation

Objective·To explore the possible roles of immune inhibitory receptor leukocyte immunoglobulin-like receptor subfamily B member 2 (LILRB2) in the immune inflammation after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and provide a potential therapeutic way for the coronavirus disease 2019 (COVID-19). Methods·The supernatants containing the extracellular domain of spike protein (S-ECD) were collected, and the detection of the protein expression and activity in the conditional medium by Western blotting and flow cytometric analysis was followed by. The binding of S-ECD with LILRB2 was measured by co-immunoprecipitation and flow cytometric analysis. The mRNA expression levels of several inflammation genes in a human mononuclear cell line (THP1) or peripheral blood mononuclear cells (PBMC) were measured after spike protein stimulation for 24 h by quantitative RT-PCR. The protein levels of interleukin-6 (IL-6) and interleukin-1β (IL-1β) in the conditional medium were examined by enzyme-linked immunosorbent assay (ELISA). The siLILRB2 was transferred into CD33+ myeloid cells purified from human peripheral blood with Lipofectamine 3000 reagents. The knockdown efficiency was detected 24 h after transfection by flow cytometric analysis. The difference in the protein levels of IL-6 between the control cells and LILRB2-knocked-down cells after spike protein treatment was evaluated by ELISA. Results·The study established a transfection system with 293T cells by which the SARSCoV-2 S-ECD could be secreted to supernatants with normal biological activities. The interaction and the binding of spike protein with LILRB2 were evaluated by a co-immunoprecipitation assay and flow cytometric analysis, respectively. The mRNA expression levels of IL-6, IL-8, arginase 1 and IL-2 in THP1 cells were significantly up-regulated 24 h after spike protein treatment compared to the control cells (all P<0.05). Consistently, the mRNA levels of IL-6, transforming growth factor-β (TGF-β), IL-8, IL-10 and IL-β in PBMC were notably increased after spike protein stimulation (all P<0.05). In addition, spike protein could also induce the release of IL-6 and IL-1β in PBMC as measured by ELISA (all P<0.05). More importantly, spike protein was able to increase the secretion of IL-1β and IL-6 by CD33+ myeloid cells 24 h after treatment (both P<0.05). LILRB2-overexpressing THP1 cells produced more IL-6 24 h after treatment with spike protein than the control cells (P<0.05). Two siRNAs could efficiently down-regulate the expression of LILRB2 in CD33+ cells as evaluated by flow cytometric analysis. Consistently, spike protein had no effect on the IL-6 secretion to supernatant from LILRB2-knockdown CD33+ myeloid cells. Conclusion·SARS-CoV-2 can induce cytokine release syndrome by inflammatory factors, such as IL-6 and IL-1β, released by myeloid cells through spike protein binding to LILRB2. © 2022 Editorial Department of Journal of Shanghai Second Medical University. All rights reserved.

[Thoughts and suggestions on co-administration of seasonal influenza vaccine and COVID-19 vaccine].

In the context of the global pandemic of COVID-19, the epidemic intensity, epidemic characteristics and infection risk of influenza have presented new features. COVID-19 and influenza have simultaneously emerged in many regions of the world. COVID-19 and influenza are similar in terms of transmission mode, clinical symptoms and other aspects. There are also similarities in the mechanism of influenza virus and novel coronavirus on cells. At the same time, it is feasible and significant to do a good job in the prevention and control of COVID-19 and influenza. This paper discusses the relevant strategies and measures for the joint prevention and control of influenza and novel coronavirus from the aspects of influenza vaccination to prevent co-infection, simultaneous vaccination of influenza vaccine and novel coronavirus vaccine, etc., and puts forward corresponding thoughts and suggestions, in order to provide scientific support for the formulation of strategies on seasonal influenza vaccine and novel coronavirus vaccination.

Parallel Transmission Effect on RF-induced Local SAR of Face Mask during 3T MRI

Since face masks may help slow the spread of diseases, a patient may wear a face mask for an MRI exam during the COVID-19 pandemic. However, metal parts, like nose or face clips within the mask, may burn the patient during an MRI. In this numerical study, we investigated the two-channel RF shimming effect on the RF-induced local SAR of a face mask with a metal strip. With the parallel transmission RF field exposure to the virtual adult male model with a face mask, the RF-induced local SAR1g is calculated for each excitation condition. Under the exposure limit of a whole-body averaged SAR of 2 W/kg and head averaged SAR of 3.2 W/kg, the peak SAR1g is 178 W/kg and 62 W/kg occurs at the nose touching the metal strip. The SAR1g value is higher on the skin area close to the metal strip than at other locations. The metal strip within the face mask could cause a potential RF-induced heating hazard. © 2022 IEEE.

Exploring spatially heterogeneous associations between COVID-19 cases and the influencing factors in England

Coronavirus pandemic (COVID-19), caused by the SARS-CoV-2 virus, has spread expeditiously around the world since early 2020 and led to a tremendous number of deaths, severely impacting overall human well-being. The pandemic largely affected economic and social activities. The beneficial way to slow down or prevent the transmission is to be well informed about the disease and how the virus spreads. Therefore, analyzing factors that affect the COVID-19 transmission was of great importance in disease control and policy decisions. Socio-demographic factors show considerable impacts on the rate of COVID-19 infection, but the correlations would vary both temporally and spatially. Generally, the global correlation coefficients of all variables rocketed at the beginning of the COVID-19 outbreak and plateaued at a high level eventually. Then localized correlations were also calculated to map the spatial distribution of correlation coefficients. Results show that in the north of England, all socio-demographic factors are highly related to the COVID-19 cases with figures above 0.75, arising from the climatic, cultural and economic differences. As time flowed for both 55+ age structure and GDP, the southern part experienced sustainable increases in correlation values, which eventually rose above 0.5 at most locations. This finding confirmed our expectation that the higher GDP was, the more COVID-19 cases were, since high GDP always accompanies by more entertainment activities and more chances for face-To-face human contact. However, the interesting point was that around London, the GDP maintained uncorrelated and even negatively correlated with the cumulative cases as time went by. As for the number of pubs, the overall spatial distribution of correlation coefficients experienced unremarkable changes at three-Time points. The variable was significantly correlated with COVID-19 cases in the north. In contrast, in the south values kept below 0.5. Overall, this study provides an interesting view on investigating the relative factors of the COVID-19 pandemic. © 2022 IEEE.

Portfolio management for typical stocks and precious metal assets

This paper examines and analyses the volatility of precious metal assets and the portfolios management. The innovative study of precious metal assets and equity portfolios is instructive and forward-looking under the background of global COVID-19. We use GARCH model, Markowitz model, CAPM Model and Fama-French Three-Factor Model to study volatility, asset forecasts, and the relationship between asset prices and markets. The results show that, firstly, precious metals are less volatile than stocks;secondly, precious metals, especially gold, make up a large percentage of rational risk-hedged portfolios;and finally, the stock prices have an almost linear relationship with the market, but precious metal prices do not have a linear relationship with the market. Our conclusion suggests that investors should consider precious metal assets, especially gold, in addition to stocks when considering their portfolios, which helps to hedge investment risk and provides some guidance to the market. © 2022 SPIE.