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1.
Chinese Medical Ethics ; JOUR(9):978-985, 35.
Article in Chinese | Scopus | ID: covidwho-2090894

ABSTRACT

COVID-19 poses a major threat to safety and health of human life. Vaccination has become an important means to resist and prevent COVID-19. Under the background of limited global supply of COVID-19 vaccine and its initial application, it is extremely necessary to discuss its ethical principles. Based on the bioethics theory and in accordance with relevant laws and regulations on vaccine use in China, this paper put forward the ethical principles of COVID-19 vaccine use, including safety principle, respect principle, fairness and justice principle, optimization principle and humanitarianism principle, which provided reference for scientifically formulating COVID-19 vaccination strategy and forming a group immune barrier to effectively control the epidemic situation in COVID-19. © 2022, Editorial department of Chinese Medical Ethics. All rights reserved.

2.
4th International Conference on Natural Language Processing, ICNLP 2022 ; : 509-513, 2022.
Article in English | Scopus | ID: covidwho-2078218

ABSTRACT

The outbreak of the COVID-19 has seriously affected the lives of the public. On the network platform, there has been a lot of controversy about this issue, which caused panic among the people. Accurate Sentiment propensity analysis of user statements on various platforms can better guide public opinion and avoid unnecessary panic. This paper classifies data based on the Naive Bayesian algorithm because the traditional Naive Bayesian algorithm does not consider that the feature weights of the same feature word in different classes are different when classifying. Under the strong hypothesis of independence between features, the same feature word has the same importance, which will reduce the accuracy of the classifier. Therefore, this paper uses an improved TF-IDF algorithm to weight it and performs classification experiments. The experimental results show that this model can achieve better performance in text classification. © 2022 IEEE.

3.
International Journal of Clinical and Experimental Medicine ; 15(8):258-265, 2022.
Article in English | EMBASE | ID: covidwho-2030810

ABSTRACT

Objectives: To explore the psychological status and perceived social support in non-anti-epidemic clinical nurses during the COVID-19 pandemic and the correlation between these two factors. Methods: Data of nonanti-epidemic clinical nurses from medical institutions in Nantong City of Jiangsu Province were collected using the Psychological Questionnaire for Emergent Events of Public Health (PQEEPH) and the Perceived Social Support Scale (PSSS) from February to March, 2020. Results: A total of 1,187 non-anti-epidemic clinical nurses were included into this study. The scores of the following dimensions in PQEEPH ranked from highest to lowest: depression (0.52±0.02) points, neurasthenia (0.37±0.01) points, fear (0.87±0.02) points, obsession-anxiety (0.24±0.01) points, and hypochondriasis (0.25±0.01) points. The total PSSS score was 63.46 points, of which, the scores of family support, friend support and other support were (21.89±4.27), (21.25±4.16) and (20.32±4.18) points respectively, indicating that these three factors had a negative correlation with emotional response. Conclusions: Non-anti-epidemic clinical nurses experience a negative psychological state during the COVID-19 pandemic and experience great support from family and friends.

4.
Journal of General Internal Medicine ; 37:S253, 2022.
Article in English | EMBASE | ID: covidwho-1995594

ABSTRACT

BACKGROUND: Social Determinants of Health (SDOH) are important drivers of well-being. Individual SDOH that are linked to specific poor health outcomes, such as unstable housing and food insecurity, are referred to as social risk factors. Historically, patient populations in Bronx County have experienced the highest rates of social risk in New York State. During the COVID-19 pandemic, the Bronx was disproportionately impacted, with local communities experiencing high rates of unemployment and COVID-19 related illness and death. The objective of this study was to determine how social risk factors changed during the pandemic in a Bronx-based patient population. METHODS: Study participants were adult patients seen at a Federally Qualified Health Center in the South Bronx. Using a paired longitudinal study design, 300 participants were randomly selected for telephonic outreach in 2020 from a sample of 865 participants who had previously been screened for social risk factors in 2019. The telephonic survey used included a social risk factor screening tool and questions regarding COVID-19 illness burden and engagement in clinic-based social services. A generalized estimating equation model was used to analyze chronological trends in reported social risk factors. RESULTS: In 2020, 44% of participants reported at least one social risk, compared to 28% in 2019 (p<0.0001). Participants who reported a personal and/or household member COVID-19 diagnosis were 1.5 times more likely to report a social risk factor during the pandemic (p=0.054). The majority of participants (76%) reported that their social risks were directly related to the pandemic, regardless of experience with COVID-19 illness. CONCLUSIONS: Social risk factors increased during the COVID-19 pandemic in a socioeconomically vulnerable, urban patient population. Pandemic related factors independent of COVID-19 illness, such as unemployment, were reported as the primary cause of increased social risks. In addition to ongoing COVID-19 vaccination and mitigation efforts, there is an urgent need to further understand and address the increased prevalence of social risk factors in at-risk communities to prevent associated poor health outcomes.

5.
Dalian Haishi Daxue Xuebao/Journal of Dalian Maritime University ; 48(1):31-41, 2022.
Article in Chinese | Scopus | ID: covidwho-1879688

ABSTRACT

Aiming at fleet deployment issue and cargo allocation issue under the background of COVID-19 epidemic and the "dual carbon" strategy, in order to meet the requirements of liner companies for the balanced development of fleet transportation efficiency, economic benefits, service quality and environmental benefits, a multi-objective fleet deployment and cargo allocation optimization model was established to achieve the goal of maximizing fleet average space utilization and operating profit, minimizing cargo time value loss and single container carbon emission. According to the internal relationship between subproblems, the model was decomposed into a two-level model. The upper level was mixed integer nonlinear programming to deal with route ship allocation and speed optimization, and the lower level was linear programming to deal with cargo allocation. The solution algorithm was designed based on NSGA-Ⅱ algorithm framework. Taking the fleet of a liner company as example, the results show that the model and the optimization solution method are feasible, and the liner company can adopt the mixed strategy of slightly increasing the speed and increasing the number of small and medium-sized ships to achieve the effect of carbon emission reduction while meeting more freight demand and coping with port congestion. © 2022, Editorial Office of Journal of Dalian Maritime University. All right reserved.

6.
Embase; 2022.
Preprint in English | EMBASE | ID: ppcovidwho-337509

ABSTRACT

The worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the repeated emergence of variants of concern. The Omicron variant has two dominant sub-lineages, BA.1 and BA.2, each with unprecedented numbers of nonsynonymous and indel spike protein mutations: 33 and 29, respectively. Some of these mutations individually increase transmissibility and enhance immune evasion, but their interactions within the Omicron mutational background is unknown. We characterize the molecular effects of all Omicron spike mutations on expression, human ACE2 receptor affinity, and neutralizing antibody recognition. We show that key mutations enable escape from neutralizing antibodies at a variety of epitopes. Stabilizing mutations in the N-terminal and S2 domains of the spike protein compensate for destabilizing mutations in the receptor binding domain, thereby enabling the record number of mutations in Omicron sub-lineages. Taken together, our results provide a comprehensive account of the mutational effects in the Omicron spike protein and illuminate previously unknown mechanisms of how the N-terminal domain can compensate for destabilizing mutations within the more evolutionarily constrained RBD.

7.
Embase; 2022.
Preprint in English | EMBASE | ID: ppcovidwho-337444

ABSTRACT

Background SARS-CoV-2 Omicron variant BA.1 first emerged on the Chinese mainland in January 2022 in Tianjin and caused a large wave of infections. During mass PCR testing, a total of 430 cases infected with Omicron were recorded between January 8 and February 7, 2022, with no new infections detected for the following 16 days. Most patients had been vaccinated with SARSCoV-2 inactivated vaccines. The disease profile associated with BA.1 infection, especially after vaccination with inactivated vaccines, is unclear. Whether BA.1 breakthrough infection after receiving inactivated vaccine could create a strong enough humoral immunity barrier against Omicron is not yet investigated. Methods We collected the clinical information and vaccination history of the 430 COVID-19 patients infected with Omicron BA.1. Re-positive cases and inflammation markers were monitored during the patient’s convalescence phase. Ordered multiclass logistic regression model was used to identify risk factors for COVID-19 disease severity. Authentic virus neutralization assays against SARS-CoV-2 wildtype, Beta and Omicron BA.1 were conducted to examine the plasma neutralizing titers induced after post-vaccination Omicron BA.1 infection, and were compared to a group of uninfected healthy individuals who were selected to have a matched vaccination profile. Findings Among the 430 patients, 316 (73.5%) were adults with a median age of 47 years, and 114 (26.5%) were under-age with a median age of 10 years. Female and male patients account for 55.6% and 44.4%, respectively. Most of the patients presented with mild (47.7%) to moderate diseases (50.2%), with only 2 severe cases (0.5%) and 7 (1.6%) asymptomatic infections. No death was recorded. 341 (79.3%) of the 430 patients received inactivated vaccines (54.3% BBIBP-CorV vs. 45.5% CoronaVac), 49 (11.4%) received adenovirus-vectored vaccines (Ad5-nCoV), 2 (0.5%) received recombinant protein subunit vaccines (ZF2001), and 38 (8.8%) received no vaccination. No vaccination is associated with a substantially higher ICU admission rate among Omicron BA.1 infected patients (2.0% for vaccinated patients vs. 23.7% for unvaccinated patients, P<0.001). Compared with adults, child patients presented with less severe illness (82.5% mild cases for children vs. 35.1% for adults, P<0.001), no ICU admission, fewer comorbidities (3.5% vs. 53.2%, P<0.001), and less chance of turning re-positive on nucleic acid tests (12.3% vs. 22.5%, P=0.019). For adult patients, compared with no prior vaccination, receiving 3 doses of inactivated vaccine was associated with significantly lower risk of severe disease (OR 0.227 [0.065-0.787], P=0.020), less ICU admission (OR 0.023 [0.002-0.214], P=0.001), lower re-positive rate on PCR (OR 0.240 [0.098-0.587], P=0.002), and shorter duration of hospitalization and recovery (OR 0.233 [0.091-0.596], P=0.002). At the beginning of the convalescence phase, patients who had received 3 doses of inactivated vaccine had substantially lower systemic immune-inflammation index (SII) and C-reactive protein than unvaccinated patients, while CD4+/CD8+ ratio, activated Treg cells and Th1/Th2 ratio were higher compared to their 2-dose counterparts, suggesting that receipt of 3 doses of inactivated vaccine could step up inflammation resolution after infection. Plasma neutralization titers against Omicron, Beta, and wildtype significantly increased after breakthrough infection with Omicron. Moderate symptoms were associated with higher plasma neutralization titers than mild symptoms. However, vaccination profiles prior to infection, whether 2 doses versus 3 doses or types of vaccines, had no significant effect on post-infection neutralization titer. Among recipients of 3 doses of CoronaVac, infection with Omicron BA.1 largely increased neutralization titers against Omicron BA.1 (8.7x), Beta (4.5x), and wildtype (2.2x), compared with uninfected healthy individuals who have a matched vaccination profile. Interpretation Receipt of 3-dose inactivated vaccines can substantially reduce the disease severity of Omicr n BA.1 infection, with most vaccinated patients presenting with mild to moderate illness. Child patients present with less severe disease than adult patients after infection. Omicron BA.1 convalescents who had received inactivated vaccines showed significantly increased plasma neutralizing antibody titers against Omicron BA.1, Beta, and wildtype SARS-CoV-2 compared with vaccinated healthy individuals.

8.
Embase; 2022.
Preprint in English | EMBASE | ID: ppcovidwho-334805

ABSTRACT

Omicron sub-lineage BA.2 has rapidly surged globally, accounting for over 60% of recent SARS-CoV-2 infections. Newly acquired RBD mutations and high transmission advantage over BA.1 urge the investigation of BA.2's immune evasion capability. Here, we show that BA.2 causes strong neutralization resistance, comparable to BA.1, in vaccinated individuals' plasma. However, BA.2 displays more severe antibody evasion in BA.1 convalescents, and most prominently, in vaccinated SARS convalescents' plasma, suggesting a substantial antigenicity difference between BA.2 and BA.1. To specify, we determined the escaping mutation profiles1,2 of 714 SARS-CoV-2 RBD neutralizing antibodies, including 241 broad sarbecovirus neutralizing antibodies isolated from SARS convalescents, and measured their neutralization efficacy against BA.1, BA.1.1, BA.2. Importantly, BA.2 specifically induces large-scale escape of BA.1/BA.1.1effective broad sarbecovirus neutralizing antibodies via novel mutations T376A, D405N, and R408S. These sites were highly conserved across sarbecoviruses, suggesting that Omicron BA.2 arose from immune pressure selection instead of zoonotic spillover. Moreover, BA.2 reduces the efficacy of S309 (Sotrovimab)3,4 and broad sarbecovirus neutralizing antibodies targeting the similar epitope region, including BD55-5840. Structural comparisons of BD55-5840 in complexes with BA.1 and BA.2 spike suggest that BA.2 could hinder antibody binding through S371F-induced N343-glycan displacement. Intriguingly, the absence of G446S mutation in BA.2 enabled a proportion of 440-449 linear epitope targeting antibodies to retain neutralizing efficacy, including COV2-2130 (Cilgavimab)5. Together, we showed that BA.2 exhibits distinct antigenicity compared to BA.1 and provided a comprehensive profile of SARS-CoV-2 antibody escaping mutations. Our study offers critical insights into the humoral immune evading mechanism of current and future variants.

9.
Zhonghua Liu Xing Bing Xue Za Zhi ; 43(4): 466-477, 2022 Apr 10.
Article in Chinese | MEDLINE | ID: covidwho-1810386

ABSTRACT

The COVID-19 pandemic is still ongoing in the world, the risk of COVID-19 spread from other countries or in the country will exist for a long term in China. In the routine prevention and control phase, a number of local COVID-19 epidemics have occurred in China, most COVID-19 cases were sporadic ones, but a few case clusters or outbreaks were reported. Winter and spring were the seasons with high incidences of the epidemics; border and port cities had higher risk for outbreaks. Active surveillance in key populations was an effective way for the early detection of the epidemics. Through a series of comprehensive prevention and control measures, including mass nucleic acid screening, close contact tracing and isolation, classified management of areas and groups at risk, wider social distancing and strict travel management, the local COVID-19 epidemics have been quickly and effectively controlled. The experiences obtained in the control of the local epidemics would benefit the routine prevention and control of COVID-19 in China. The occurrence of a series of COVID-19 case clusters or outbreaks has revealed the weakness or deficiencies in the COVID-19 prevention and control in China, so this paper suggests some measures for the improvement of the future prevention and control of COVID-19.


Subject(s)
COVID-19 , Epidemics , COVID-19/epidemiology , COVID-19/prevention & control , China/epidemiology , Contact Tracing , Epidemics/prevention & control , Humans , Pandemics/prevention & control , SARS-CoV-2
10.
PubMed; 2020.
Preprint in English | PubMed | ID: ppcovidwho-333557

ABSTRACT

A spike protein mutation D614G became dominant in SARS-CoV-2 during the COVID-19 pandemic. However, the mutational impact on viral spread and vaccine efficacy remains to be defined. Here we engineer the D614G mutation in the SARS-CoV-2 USA-WA1/2020 strain and characterize its effect on viral replication, pathogenesis, and antibody neutralization. The D614G mutation significantly enhances SARS-CoV-2 replication on human lung epithelial cells and primary human airway tissues, through an improved infectivity of virions with the spike receptor-binding domain in an "up" conformation for binding to ACE2 receptor. Hamsters infected with D614 or G614 variants developed similar levels of weight loss. However, the G614 virus produced higher infectious titers in the nasal washes and trachea, but not lungs, than the D614 virus. The hamster results confirm clinical evidence that the D614G mutation enhances viral loads in the upper respiratory tract of COVID-19 patients and may increases transmission. For antibody neutralization, sera from D614 virus-infected hamsters consistently exhibit higher neutralization titers against G614 virus than those against D614 virus, indicating that (i) the mutation may not reduce the ability of vaccines in clinical trials to protect against COVID-19 and (ii) therapeutic antibodies should be tested against the circulating G614 virus before clinical development. IMPORTANCE: Understanding the evolution of SARS-CoV-2 during the COVID-19 pandemic is essential for disease control and prevention. A spike protein mutation D614G emerged and became dominant soon after the pandemic started. By engineering the D614G mutation into an authentic wild-type SARS-CoV-2 strain, we demonstrate the importance of this mutation to (i) enhanced viral replication on human lung epithelial cells and primary human airway tissues, (ii) improved viral fitness in the upper airway of infected hamsters, and (iii) increased susceptibility to neutralization. Together with clinical findings, our work underscores the importance of this mutation in viral spread, vaccine efficacy, and antibody therapy.

11.
PubMed; 2020.
Preprint in English | PubMed | ID: ppcovidwho-333556

ABSTRACT

SARS-CoV-2 has resulted in a global pandemic and shutdown economies around the world. Sequence analysis indicates that the novel coronavirus (CoV) has an insertion of a furin cleavage site (PRRAR) in its spike protein. Absent in other group 2B CoVs, the insertion may be a key factor in the replication and virulence of SARS-CoV-2. To explore this question, we generated a SARS-CoV-2 mutant lacking the furin cleavage site (DELTAPRRA) in the spike protein. This mutant virus replicated with faster kinetics and improved fitness in Vero E6 cells. The mutant virus also had reduced spike protein processing as compared to wild-type SARS-CoV-2. In contrast, the DELTAPRRA had reduced replication in Calu3 cells, a human respiratory cell line, and had attenuated disease in a hamster pathogenesis model. Despite the reduced disease, the DELTAPRRA mutant offered robust protection from SARS-CoV-2 rechallenge. Importantly, plaque reduction neutralization tests (PRNT 50 ) with COVID-19 patient sera and monoclonal antibodies against the receptor-binding domain found a shift, with the mutant virus resulting in consistently reduced PRNT 50 titers. Together, these results demonstrate a critical role for the furin cleavage site insertion in SARS-CoV-2 replication and pathogenesis. In addition, these findings illustrate the importance of this insertion in evaluating neutralization and other downstream SARS-CoV-2 assays. IMPORTANCE: As COVID-19 has impacted the world, understanding how SARS-CoV-2 replicates and causes virulence offers potential pathways to disrupt its disease. By removing the furin cleavage site, we demonstrate the importance of this insertion to SARS-CoV-2 replication and pathogenesis. In addition, the findings with Vero cells indicate the likelihood of cell culture adaptations in virus stocks that can influence reagent generation and interpretation of a wide range of data including neutralization and drug efficacy. Overall, our work highlights the importance of this key motif in SARS-CoV-2 infection and pathogenesis. ARTICLE SUMMARY: A deletion of the furin cleavage site in SARS-CoV-2 amplifies replication in Vero cells, but attenuates replication in respiratory cells and pathogenesis in vivo. Loss of the furin site also reduces susceptibility to neutralization in vitro .

12.
20th International Conference on Ubiquitous Computing and Communications, 20th International Conference on Computer and Information Technology, 4th International Conference on Data Science and Computational Intelligence and 11th International Conference on Smart Computing, Networking, and Services, IUCC/CIT/DSCI/SmartCNS 2021 ; : 92-99, 2021.
Article in English | Scopus | ID: covidwho-1788746

ABSTRACT

Against the Covid-19 background, vaccine safety has aroused the wild attention of all social areas. However, the factors that cause vaccine safety risks are complicated and meanwhile, data is difficult to obtain, making it a challenge for analyzing vaccine safety risks quantitatively. This paper concretises the issue of vaccine system safety by creatively proposing an analytical framework for the problem of uncertainty. First, the paper focuses on the whole process of vaccine safety, analyses risk factors affecting vaccine safety in development, approval, production, transportation, and supervision of vaccines in order to build a vaccine risk assessment system. The proposed framework is then used to construct a Bayesian network early warning system for vaccine risk. To address the difficulty of obtaining data, the probability of safety risks occurring throughout the process is calculated by combining expert knowledge and fuzzy set theory to obtain uncertainty data. In response to structural complexity, a comprehensive framework is constructed using fault trees and Bayesian networks to capture the correlation between risk factors. This analytical framework can provide guidance to governments and vaccine-related companies in their decision-making to prevent vaccine safety issues. Finally, sensitivity analysis revealed a high probability of vaccine risk in the transport process. © 2021 IEEE.

13.
PubMed; 2022.
Preprint in English | PubMed | ID: ppcovidwho-332321

ABSTRACT

While SARS-CoV-2 continues to adapt for human infection and transmission, genetic variation outside of the spike gene remains largely unexplored. This study investigates a highly variable region at residues 203-205 in the SARS-CoV-2 nucleocapsid protein. Recreating a mutation found in the alpha and omicron variants in an early pandemic (WA-1) background, we find that the R203K+G204R mutation is sufficient to enhance replication, fitness, and pathogenesis of SARS-CoV-2. The R203K+G204R mutant corresponds with increased viral RNA and protein both in vitro and in vivo . Importantly, the R203K+G204R mutation increases nucleocapsid phosphorylation and confers resistance to inhibition of the GSK-3 kinase, providing a molecular basis for increased virus replication. Notably, analogous alanine substitutions at positions 203+204 also increase SARS-CoV-2 replication and augment phosphorylation, suggesting that infection is enhanced through ablation of the ancestral 'RG' motif. Overall, these results demonstrate that variant mutations outside spike are key components in SARS-CoV-2's continued adaptation to human infection. Author Summary: Since its emergence, SARS-CoV-2 has continued to adapt for human infection resulting in the emergence of variants with unique genetic profiles. Most studies of genetic variation have focused on spike, the target of currently available vaccines, leaving the importance of variation elsewhere understudied. Here, we characterize a highly variable motif at residues 203-205 in nucleocapsid. Recreating the prominent nucleocapsid R203K+G204R mutation in an early pandemic background, we show that this mutation is alone sufficient to enhance SARS-CoV-2 replication and pathogenesis. We also link augmentation of SARS-CoV-2 infection by the R203K+G204R mutation to its modulation of nucleocapsid phosphorylation. Finally, we characterize an analogous alanine double substitution at positions 203-204. This mutant was found to mimic R203K+G204R, suggesting augmentation of infection occurs by disrupting the ancestral sequence. Together, our findings illustrate that mutations outside of spike are key components of SARS-CoV-2's adaptation to human infection.

14.
2nd International Conference on Consumer Electronics and Computer Engineering, ICCECE 2022 ; : 921-924, 2022.
Article in English | Scopus | ID: covidwho-1774637

ABSTRACT

With the development of 5G and the emergence of the COVID-19 epidemic, network traffic has surged, and network security has once again become a key concern. Intrusion detection system is an important means to protect network security. It can find abnormal conditions in the early stage of cyber attack. Intrusion detection is also a kind of abnormal detection in a broad sense. To improve the performance of the intrusion detection system, a cyber-attack detection method combining Borderline SMOTE and improved BP neural network (Back-Propagation neural network) is proposed. It mainly uses one-hot encoding, Borderline SMOTE data oversampling and other technologies to preprocess the data, and uses the BP neural network improved by genetic algorithm to predict cyber attacks. Finally, the model is compared with other traditional machine learning models through the core indicator recall and auxiliary indicators precision, roc curve, etc. The results show that the hybrid detection model proposed in this study has higher recall and lower running time, and performs better in intrusion detection. © 2022 IEEE.

15.
2021 Winter Simulation Conference, WSC 2021 ; 2021-December, 2021.
Article in English | Scopus | ID: covidwho-1746008

ABSTRACT

Developing and using the rich data implied by dynamic digital twins and blockchain is relevant to manage both patients and medical resources (e.g., doctors/nurses, ventilators etc.) at the COVID-19 and post COVID period. This paper aims at exploring the blockchain solutions for preparing healthcare systems ready for both efficient operation daily and in pandemic through (1) information integration of patient and medical resource flow from healthcare and medical records;(2) optimizing the deployment of such resources based on hospitals, regions and local pandemic levels switching from normal to the outbreak. The main idea is to develop the concepts of the novel framework for creating an inter-hospital resilient network for pandemic response based on blockchain and dynamic digital twin, which will set up innovative ways to best care for patients, protect NHS staff, and support government scientific decisions to beat COVID-19 now and manage the crisis in the future. © 2021 IEEE.

17.
Global Journal of Environmental Science and Management ; 6(Special Issue):107-118, 2020.
Article in English | GIM | ID: covidwho-1727157

ABSTRACT

The coronavirus disease 2019 (COVID-19) has been identified as the main cause of the outbreak of the respiratory disease in Wuhan, Hubei Province of China in December 2019. Since then, the epidemic has spread rapidly throughout China and many other countries in the world. This study, therefore, examines the spatiotemporal distribution of the confirmed cases of COVID-19 and its effect on human development in China, and suggested social and non-pharmaceutical preventive interventions to help curb the further spread of the disease. The public open data available from January to February 2020, from the National Health Commission of the People's Republic of China and a medical knowledge sharing website were used, and spatial analysis was performed to visualize the spatial distribution pattern of COVID-19 in China. The results showed among others that COVID-19 had entered a dispersed spatial pattern, resulting in increased pressure to control the spread of the disease. In early March, there was a significant reduction in the existing number of cases, and the number of deaths also decreased. At the provincial level, the spatial distribution of the number of cumulative confirmed cases in China was divided into four patterns: Hubei was the initial core region;the eastern provinces adjacent to Hubei formed the second concentrated pattern;the western provinces adjacent to Hubei and the northeastern and southeastern provinces which were separated from Hubei by one province belonged to the third distribution pattern;while the rest of the provinces in the north, south and west showing sporadic distribution patterns formed the fourth. It has been estimated that about 80% of students' online learning at all schools were not effective due to lack of access to reliable and uninterrupted internet services especially in the rural areas of China.

18.
Managerial and Decision Economics ; : 25, 2022.
Article in English | Web of Science | ID: covidwho-1718429

ABSTRACT

This study considers a differentiated duopoly, including domestic and foreign enterprises, in trade, analyzes the impacts of product differentiation and productivity variance on equilibrium results, and explores the optimal trade policy in different competition modes. We find that differentiated products can boost the supply of foreign enterprises in a Cournot competition. In a home-leading Stackelberg duopoly, increasing tariffs decreases consumer surplus but improves the home country's social welfare. The optimum-welfare tariff of a home-leading Stackelberg duopoly cannot exceed that of the foreign-leading Stackelberg duopoly. An easy or tight tariff policy can be optimal, depending on the parameters and duopoly modes.

19.
IEEE Access ; 2022.
Article in English | Scopus | ID: covidwho-1699540

ABSTRACT

This paper proposes a new multi-kernel learning ensemble algorithm, called Ada-L1MKL-WSVR, which can be regarded as an extension of multi-kernel learning (MKL) and weighted support vector regression (WSVR). The first novelty is to add the L1 norm of the weights of the combined kernel function to the objective function of WSVR, which is used to adaptively select the optimal base models and their parameters. In addition, an accelerated method based on fast iterative shrinkage thresholding algorithm (FISTA) is developed to solve the weights of the combined kernel function. The second novelty is to propose an integrated learning framework based on AdaBoost, named Ada-L1MKL-WSVR. In this framework, we integrate FISTA into AdaBoost. At each iteration, we optimize the weights of the combined kernel function and update the weights of the training samples at the same time. Then an ensemble regression function of a set of regression functions is output. Finally, two groups of the experiments are designed to verify the performance of our algorithm. On the first group of the experiments including eight datasets from UCI machine learning repository, the MAEs and RMSEs of Ada-L1MKL-WSVR are reduced by 11.14% and 9.08% on average, respectively. Furthermore, on the second group of the experiments including the COVID-19 epidemic datasets from eight countries, the MAEs and RMSEs of Ada-L1MKL-WSVR are reduced by 31.19% and 29.98% on average, respectively. Author

20.
MEDLINE;
Preprint in English | MEDLINE | ID: ppcovidwho-327320

ABSTRACT

One major limitation of neutralizing antibody-based COVID-19 therapy is the requirement of costly cocktails to reduce antibody resistance. We engineered two bispecific antibodies (bsAbs) using distinct designs and compared them with parental antibodies and their cocktail. Single molecules of both bsAbs block the two epitopes targeted by parental antibodies on the receptor-binding domain (RBD). However, bsAb with the IgG-(scFv) 2 design (14-H-06) but not the CrossMAb design (14-crs-06) increases antigen-binding and virus-neutralizing activities and spectrum against multiple SARS-CoV-2 variants including the Omicron, than the cocktail. X-ray crystallography and computational simulations reveal distinct neutralizing mechanisms for individual cocktail antibodies and suggest higher inter-spike crosslinking potentials by 14-H-06 than 14-crs-06. In mouse models of infections by SARS-CoV-2 and the Beta, Gamma, and Delta variants, 14-H-06 exhibits higher or equivalent therapeutic efficacy than the cocktail. Rationally engineered bsAbs represent a cost-effective alternative to antibody cocktails and a promising strategy to improve potency and breadth.

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