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2.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-318042

ABSTRACT

In the current pandemic of COVID-19, students and faculty are subject to social distancing and online learning. How to test students in this unprecedented environment is a new educational challenge with immediate and global impacts. The main contribution of this paper is to establish the feasibility that by a clever design we can control the average gain (which is referred to as the g-factor) from cheating behaviors to a degree as small as pre-specified so that accurate and reliable online exams can be administered. It is underlined that even after the pandemic the methods and systems in the spirit of our proposal are still valuable for cost-effective exams to promote open courses and internet-based education.

3.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315323

ABSTRACT

Background: In December 2019, the world awoke to a new zoonotic strain of coronavirus named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Results: : In the present study, we classified betacoronavirus subgroup B into the SARS-CoV-2, SARS-CoV and SARS-like CoV clusters, and the ORF8 genes of these three clusters into types 1, 2 and 3, respectively. One important result of our study is that we reported—for the first time—a recombination event of ORF8 at the whole-gene level in a bat, which had been co-infected by two betacoronavirus strains. This result provides substantial proof for long-existing hypotheses regarding the recombination and biological functions of ORF8. Based on the analysis of recombination events in the Spike gene, we propose that the Spike protein of SARS-CoV-2 may have more than one specific receptor for its function as gp120 of HIV has CD4 and CCR5. In the present study, we also found that the ancestor of betacoronavirus had a strong first Internal Ribosome Entry Site (IRES) and at least one furin cleavage site (FCS) in the junction region between S1 and S2 subunits. Conclusions: : We concluded that the junction FCS in SARS-CoV-2 may increase the efficiency of its entry into cells, while the type 2 ORF8 acquired by SARS-CoV may increase its replication efficiency. These two most critical events provide the most likely explanation for SARS and COVID-19 pandemics.

4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-325036

ABSTRACT

Background: The aim of this study was to assess the characteristics of hip fracture during the novel coronavirus (COVID-19) epidemic. Method: Hip-facture patients undergoing surgery from January 26 to March 31, 2020 (group A) and from January 26 to March 31, 2019 (group B) were retrospectively included. The durations from injury onset to hospital discharge, hospitalization cost, comorbidity, and complications of patients in the two groups were collected. The daily activity and light exposure time, and medical treatment interruption of patients in group A before and during their self-quarantine were also collected. In addition, the reasons for those with hospital admission delay were inquired. Results: During the COVID-19 epidemic, patients with hip fracture was increased by 9 cases (69.23%). Patients in group A underwent an over 20-hour longer duration from the injury onset to hospital, an over 3-day longer hospitalization stay, and more hospitalization cost of over 4-thousand yuan compared with those for patients in group B (P < 0.05). The self-quarantine led to reduced daily activities (P <0.001), reduced light exposure time (P <0.001) and more medical interruption for hip-fracture patients. There were also slight more comorbidity number and perioperative complications for patients in group A compared with patients in group B. For those with a pre-hospital time more than 24 h, 58.33% feared go out for medical treatment because of the COVID-19 epidemic. Conclusion: During the COVID-19 epidemic period, the prevention and management of hip-fracture for the elderly require more attention for the public and medical care personnel.

5.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-324498

ABSTRACT

Background: Previous studies have shown that Coronavirus Disease 2019 (COVID-19) patients with underlying comorbidities can have worse outcomes. However, the effect of hypertension on outcomes of COVID-19 patients remains unclear. Research Question: The aim of this study was to explore the effect of hypertension on the outcomes of patients with COVID-19 by using propensity score–matching (PSM) analysis. Study Design and Methods: Participants enrolled in this study were patients with COVID-19 who had been hospitalized at the Central Hospital of Wuhan, China. Chronic comorbidities and laboratory and radiological data were reviewed;patient outcomes and lengths of stay were obtained from discharge records. We used the Cox proportional-hazard model (CPHM) to analyze the effect of hypertension on these patients’ outcomes and PSM analysis to further validate the abovementioned effect. Results: : A total of 226 patients with COVID-19 were enrolled in this study, of whom 176 survived and 50 died. The proportion of patients with hypertension among non-survivors was higher than that among survivors (26.70% vs. 74.00%;P < 0.001). Results obtained via CPHM showed that hypertension could increase risk of mortality in COVID-19 patients (hazard ratio 3.317;95% CI [1.709–6.440];P < 0.001). Increased D-dimer levels and higher ratio of neutrophils to lymphocytes (N/L) were also found to increase these patients’ mortality risk. After matching on propensity score, we still came to similar conclusions. After we applied the same method in critically ill patients, we found that hypertension also increased risk of death in patients with severe COVID-19. Conclusion: Hypertension, increased D-dimer and the ratio of neutrophil to lymphocyte increased mortality in patients with COVID-19, with hypertension in particular.

6.
Proc Natl Acad Sci U S A ; 119(4)2022 01 25.
Article in English | MEDLINE | ID: covidwho-1621335

ABSTRACT

After binding to its cell surface receptor angiotensin converting enzyme 2 (ACE2), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters the host cell through directly fusing with plasma membrane (cell surface pathway) or undergoing endocytosis traveling to lysosome/late endosome for membrane fusion (endocytic pathway). However, the endocytic entry regulation by host cell remains elusive. Recent studies show ACE2 possesses a type I PDZ binding motif (PBM) through which it could interact with a PDZ domain-containing protein such as sorting nexin 27 (SNX27). In this study, we determined the ACE2-PBM/SNX27-PDZ complex structure, and, through a series of functional analyses, we found SNX27 plays an important role in regulating the homeostasis of ACE2 receptor. More importantly, we demonstrated SNX27, together with retromer complex (the core component of the endosomal protein sorting machinery), prevents ACE2/virus complex from entering lysosome/late endosome, resulting in decreased viral entry in cells where the endocytic pathway dominates. The ACE2/virus retrieval mediated by SNX27-retromer could be considered as a countermeasure against invasion of ACE2 receptor-using SARS coronaviruses.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , Endosomes/metabolism , SARS-CoV-2 , Sorting Nexins/chemistry , COVID-19/virology , Cell Line , Cell Line, Tumor , Cell Membrane/metabolism , Crystallography, X-Ray , Cytosol/metabolism , Endocytosis , Gene Expression Profiling , HEK293 Cells , HeLa Cells , Homeostasis , Humans , Lentivirus , Lysosomes/metabolism , Peptides/chemistry , Protein Binding , Protein Conformation , Protein Domains , Sorting Nexins/metabolism , Virus Internalization
7.
COVID ; 2(1):5-17, 2022.
Article in English | MDPI | ID: covidwho-1580968

ABSTRACT

Human coronaviruses (HCoVs) are associated with a range of respiratory symptoms. The discovery of severe acute respiratory syndrome (SARS)-CoV, Middle East respiratory syndrome, and SARS-CoV-2 pose a significant threat to human health. In this study, we developed a method (HCoV-MS) that combines multiplex PCR with matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), to detect and differentiate seven HCoVs simultaneously. The HCoV-MS method had high specificity and sensitivity, with a 1–5 copies/reaction detection limit. To validate the HCoV-MS method, we tested 163 clinical samples, and the results showed good concordance with real-time PCR. Additionally, the detection sensitivity of HCoV-MS and real-time PCR was comparable. The HCoV-MS method is a sensitive assay, requiring only 1 μL of a sample. Moreover, it is a high-throughput method, allowing 384 samples to be processed simultaneously in 30 min. We propose that this method be used to complement real-time PCR for large-scale screening studies.

8.
Front Med (Lausanne) ; 8: 722219, 2021.
Article in English | MEDLINE | ID: covidwho-1518491

ABSTRACT

The tolerance of certain multi-drug resistant bacteria to disinfectants may be promoted while the requirements of environmental disinfection have been raised in the high-risk areas of medical institutions during the COVID-19 pandemic. The current research addressed the mechanisms underlying a sharp increase in the detection of methicillin-resistant Staphylococcus aureus (MRSA) observed in a closed-management unit of elderly patients with mental disorders in 2020 as compared with the previous 4 years. We first conducted microbial detection in staff-hand and environment and a molecular epidemiology analysis, rejecting the hypothesis that the MRSA increase was due to an outbreak. Afterward, we turned to disinfectant concentration and frequency of use and analyzed the varied MRSA detection rates with different concentrations and frequencies of disinfection in 2020 and the previous 4 years. The MRSA detection rate increased with elevated concentration and frequency of disinfection, with 1,000 or 500 mg/L two times per day since January in 2020 vs. 500 mg/L 2-3 times per week in 2016-2019. When the disinfectant concentration was reduced from 1,000 to 500 mg/L, the MRSA detection decreased which indicated a modulatory role of disinfectant concentration. With a sustained frequency of disinfection in 2020, the MRSA detection rate was still higher, even after May, than that in the previous years. This suggested that the frequency of disinfection also contributed to the MRSA increase. Overall, the MRSA detection was augmented with the increase in disinfection concentration and frequency during the COVID-19 epidemic, suggesting that highly-concentrated and highly-frequent preventive long-term disinfection is not recommended without risk assessments in psychiatric hospitals.

9.
Journal of Medical Virology ; 94(1):i-i, 2022.
Article in English | Wiley | ID: covidwho-1508788

ABSTRACT

Front Cover Caption: The cover image is based on the Research Article Palmitoylation of SARS-CoV-2 S protein is critical for S-mediated syncytia formation and virus entry by Daoqun Li et al., https://doi.org/10.1002/jmv.27339.

10.
World J Clin Cases ; 9(28): 8388-8403, 2021 Oct 06.
Article in English | MEDLINE | ID: covidwho-1513223

ABSTRACT

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) pandemic is a global threat caused by the severe acute respiratory syndrome coronavirus-2. AIM: To develop and validate a risk stratification tool for the early prediction of intensive care unit (ICU) admission among COVID-19 patients at hospital admission. METHODS: The training cohort included COVID-19 patients admitted to the Wuhan Third Hospital. We selected 13 of 65 baseline laboratory results to assess ICU admission risk, which were used to develop a risk prediction model with the random forest (RF) algorithm. A nomogram for the logistic regression model was built based on six selected variables. The predicted models were carefully calibrated, and the predictive performance was evaluated and compared with two previously published models. RESULTS: There were 681 and 296 patients in the training and validation cohorts, respectively. The patients in the training cohort were older than those in the validation cohort (median age: 63.0 vs 49.0 years, P < 0.001), and the percentages of male gender were similar (49.6% vs 49.3%, P = 0.958). The top predictors selected in the RF model were neutrophil-to-lymphocyte ratio, age, lactate dehydrogenase, C-reactive protein, creatinine, D-dimer, albumin, procalcitonin, glucose, platelet, total bilirubin, lactate and creatine kinase. The accuracy, sensitivity and specificity for the RF model were 91%, 88% and 93%, respectively, higher than those for the logistic regression model. The area under the receiver operating characteristic curve of our model was much better than those of two other published methods (0.90 vs 0.82 and 0.75). Model A underestimated risk of ICU admission in patients with a predicted risk less than 30%, whereas the RF risk score demonstrated excellent ability to categorize patients into different risk strata. Our predictive model provided a larger standardized net benefit across the major high-risk range compared with model A. CONCLUSION: Our model can identify ICU admission risk in COVID-19 patients at admission, who can then receive prompt care, thus improving medical resource allocation.

11.
J Med Virol ; 94(1): 342-348, 2022 01.
Article in English | MEDLINE | ID: covidwho-1437056

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing coronavirus disease 2019 (COVID-19) pandemic. The S protein is the key viral protein for associating with ACE2, the receptor for SARS-CoV-2. There are many kinds of posttranslational modifications in S protein. However, the detailed mechanism of palmitoylation of SARS-CoV-2 S remains to be elucidated. In our current study, we characterized the palmitoylation of SARS-CoV-2 S. Both the C15 and cytoplasmic tail of SARS-CoV-2 S were palmitoylated. Fatty acid synthase inhibitor C75 and zinc finger DHHC domain-containing palmitoyltransferase (ZDHHC) inhibitor 2-BP reduced the palmitoylation of S. Interestingly, palmitoylation of SARS-CoV-2 S was not required for plasma membrane targeting of S but was critical for S-mediated syncytia formation and SARS-CoV-2 pseudovirus particle entry. Overexpression of ZDHHC2, ZDHHC3, ZDHHC4, ZDHHC5, ZDHHC8, ZDHHC9, ZDHHC11, ZDHHC14, ZDHHC16, ZDHHC19, and ZDHHC20 promoted the palmitoylation of S. Furthermore, those ZDHHCs were identified to associate with SARS-CoV-2 S. Our study not only reveals the mechanism of S palmitoylation but also will shed important light into the role of S palmitoylation in syncytia formation and virus entry.


Subject(s)
Cell Membrane/metabolism , Giant Cells/metabolism , Lipoylation/physiology , Spike Glycoprotein, Coronavirus/metabolism , Virus Internalization , 4-Butyrolactone/analogs & derivatives , 4-Butyrolactone/pharmacology , Acyltransferases/antagonists & inhibitors , COVID-19/pathology , Cell Line , HEK293 Cells , Humans , Protein Processing, Post-Translational/physiology
12.
Future Gener Comput Syst ; 127: 334-346, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1433239

ABSTRACT

This study was aimed to discuss the predictive value of infectious disease dynamics model (IDD model) and dynamic Bayesian network (DBN) for scenario deduction of public health emergencies (PHEs). Based on the evolution law of PHEs and the meta-scenario representation of basic knowledge, this study established a DBN scenario deduction model for scenario deduction and evolution path analysis of PHEs. At the same time, based on the average field dynamics model of the SIR network, the dimensionality reduction process was performed to calculate the epidemic scale and epidemic time based on the IDD model, so as to determine the calculation methods of threshold value and epidemic time under emergency measures (quarantine). The Corona Virus Disease (COVID) epidemic was undertaken as an example to analyze the results of DBN scenario deduction, and the infectious disease dynamics model was used to analyze the number of reproductive numbers, peak arrival time, epidemic time, and latency time of the COVID epidemic. It was found that after the M1 measure was used to process the S1 state, the state probability and the probability of being true (T) were the highest, which were 91.05 and 90.21, respectively. In the sixth stage of the development of the epidemic, the epidemic had developed to level 5, the number of infected people was about 26, and the estimated loss was about 220 million yuan. The comprehensive cumulative foreground (CF) values of O1  ∼  O3 schemes were -1.34, -1.21, and -0.77, respectively, and the final CF values were -1.35, 0.01, and -0.08, respectively. The final CF value of O2 was significantly higher than the other two options. The household infection probability was the highest, which was 0.37 and 0.35 in Wuhan and China, respectively. Under the measures of home quarantine, the numbers of confirmed cases of COVID in China and Wuhan were 1.503 (95% confidential interval (CI) = 1.328  ∼  1.518) and 1.729 (95% CI = 1.107  ∼  1.264), respectively, showing good fits with the real data. On the 21st day after the quarantine measures were taken, the number of COVID across the country had an obvious peak, with the confirmed cases of 24495, and the model prediction value was 24085 (95% CI = 23988  ∼  25056). The incubation period 1/q was shortened from 8 days to 3 days, and the number of confirmed cases showed an upward trend. The peak period of confirmed cases was advanced, shortening the overall epidemic time. It showed that the prediction results of scenario deduction based on DBN were basically consistent with the actual development scenario and development status of the epidemic. It could provide corresponding decisions for the prevention and control of COVID based on the relevant parameters of the infectious disease dynamic model, which verified the rationality and feasibility of the scenario deduction method proposed in this study.

13.
Cell ; 184(1): 184-193.e10, 2021 01 07.
Article in English | MEDLINE | ID: covidwho-1385213

ABSTRACT

Transcription of SARS-CoV-2 mRNA requires sequential reactions facilitated by the replication and transcription complex (RTC). Here, we present a structural snapshot of SARS-CoV-2 RTC as it transitions toward cap structure synthesis. We determine the atomic cryo-EM structure of an extended RTC assembled by nsp7-nsp82-nsp12-nsp132-RNA and a single RNA-binding protein, nsp9. Nsp9 binds tightly to nsp12 (RdRp) NiRAN, allowing nsp9 N terminus inserting into the catalytic center of nsp12 NiRAN, which then inhibits activity. We also show that nsp12 NiRAN possesses guanylyltransferase activity, catalyzing the formation of cap core structure (GpppA). The orientation of nsp13 that anchors the 5' extension of template RNA shows a remarkable conformational shift, resulting in zinc finger 3 of its ZBD inserting into a minor groove of paired template-primer RNA. These results reason an intermediate state of RTC toward mRNA synthesis, pave a way to understand the RTC architecture, and provide a target for antiviral development.


Subject(s)
Coronavirus RNA-Dependent RNA Polymerase/chemistry , Cryoelectron Microscopy , RNA, Messenger/chemistry , RNA, Viral/chemistry , SARS-CoV-2/chemistry , Viral Replicase Complex Proteins/chemistry , Amino Acid Sequence , Coronavirus/chemistry , Coronavirus/classification , Coronavirus/enzymology , Coronavirus RNA-Dependent RNA Polymerase/metabolism , Methyltransferases/metabolism , Models, Molecular , RNA Helicases/metabolism , RNA-Binding Proteins/chemistry , RNA-Binding Proteins/metabolism , SARS-CoV-2/enzymology , Sequence Alignment , Transcription, Genetic , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism , Virus Replication
14.
Int J Environ Res Public Health ; 18(15)2021 07 22.
Article in English | MEDLINE | ID: covidwho-1323820

ABSTRACT

The rebound of online public opinion is an important driving force in inducing a secondary crisis in the case of public emergencies. Effective risk-information communication is an important means to manage online public opinion regarding emergencies. This paper employs fuzzy-set qualitative comparative analysis to discover which conditions are combined and may result in the rebound of online public opinion. Five conditions were selected: the type of public emergency, messengers, message attributes, audience, and information feedback. The study used a sample of 25 major public emergencies that occurred between 2015 and 2020 in China. The type of public emergency, audience, and information feedback emerged as critical influencing factors. Message attributes promote the rebound of online public opinion regarding public health emergencies, while messengers play a traction role in the rebound of online public opinion on other types of public emergencies. This study extends risk-information communication theory from the perspective of the type of emergency, explores the causes of rebounded online public opinion regarding public emergencies, and provides policies and suggestions for risk-information communication and online public-opinion governance during emergencies.


Subject(s)
Emergencies , Public Opinion , China , Communication , Humans , Public Health
15.
J Infect ; 83(4): 496-522, 2021 10.
Article in English | MEDLINE | ID: covidwho-1313249
16.
Cell ; 184(13): 3474-3485.e11, 2021 06 24.
Article in English | MEDLINE | ID: covidwho-1240208

ABSTRACT

The capping of mRNA and the proofreading play essential roles in SARS-CoV-2 replication and transcription. Here, we present the cryo-EM structure of the SARS-CoV-2 replication-transcription complex (RTC) in a form identified as Cap(0)-RTC, which couples a co-transcriptional capping complex (CCC) composed of nsp12 NiRAN, nsp9, the bifunctional nsp14 possessing an N-terminal exoribonuclease (ExoN) and a C-terminal N7-methyltransferase (N7-MTase), and nsp10 as a cofactor of nsp14. Nsp9 and nsp12 NiRAN recruit nsp10/nsp14 into the Cap(0)-RTC, forming the N7-CCC to yield cap(0) (7MeGpppA) at 5' end of pre-mRNA. A dimeric form of Cap(0)-RTC observed by cryo-EM suggests an in trans backtracking mechanism for nsp14 ExoN to facilitate proofreading of the RNA in concert with polymerase nsp12. These results not only provide a structural basis for understanding co-transcriptional modification of SARS-CoV-2 mRNA but also shed light on how replication fidelity in SARS-CoV-2 is maintained.


Subject(s)
Coronavirus RNA-Dependent RNA Polymerase/genetics , Exoribonucleases/genetics , Methyltransferases/genetics , SARS-CoV-2/genetics , Amino Acid Sequence , COVID-19/virology , Humans , RNA, Messenger/genetics , RNA, Viral/genetics , Sequence Alignment , Transcription, Genetic/genetics , Virus Replication/genetics
17.
Front Microbiol ; 12: 614494, 2021.
Article in English | MEDLINE | ID: covidwho-1170096

ABSTRACT

In December 2019, the world awoke to a new betacoronavirus strain named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Betacoronavirus consists of A, B, C and D subgroups. Both SARS-CoV and SARS-CoV-2 belong to betacoronavirus subgroup B. In the present study, we divided betacoronavirus subgroup B into the SARS1 and SARS2 classes by six key insertions and deletions (InDels) in betacoronavirus genomes, and identified a recently detected betacoronavirus strains RmYN02 as a recombinant strain across the SARS1 and SARS2 classes, which has potential to generate a new strain with similar risk as SARS-CoV and SARS-CoV-2. By analyzing genomic features of betacoronavirus, we concluded: (1) the jumping transcription and recombination of CoVs share the same molecular mechanism, which inevitably causes CoV outbreaks; (2) recombination, receptor binding abilities, junction furin cleavage sites (FCSs), first hairpins and ORF8s are main factors contributing to extraordinary transmission, virulence and host adaptability of betacoronavirus; and (3) the strong recombination ability of CoVs integrated other main factors to generate multiple recombinant strains, two of which evolved into SARS-CoV and SARS-CoV-2, resulting in the SARS and COVID-19 pandemics. As the most important genomic features of SARS-CoV and SARS-CoV-2, an enhanced ORF8 and a novel junction FCS, respectively, are indispensable clues for future studies of their origin and evolution. The WIV1 strain without the enhanced ORF8 and the RaTG13 strain without the junction FCS "RRAR" may contribute to, but are not the immediate ancestors of SARS-CoV and SARS-CoV-2, respectively.

18.
Front Genet ; 12: 641445, 2021.
Article in English | MEDLINE | ID: covidwho-1133907

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although a preliminary understanding of the replication and transcription of SARS-CoV-2 has recently emerged, their regulation remains unknown. RESULTS: By comprehensive analysis of genome sequence and protein structure data, we propose a negative feedback model to explain the regulation of CoV replication and transcription, providing a molecular basis of the "leader-to-body fusion" model. The key step leading to the proposal of our model was that the transcription regulatory sequence (TRS) motifs were identified as the cleavage sites of nsp15, a nidoviral RNA uridylate-specific endoribonuclease (NendoU). According to this model, nsp15 regulates the synthesis of subgenomic RNAs (sgRNAs), and genomic RNAs (gRNAs) by cleaving TRSs. The expression level of nsp15 controls the relative proportions of sgRNAs and gRNAs, which in turn change the expression level of nsp15 to reach equilibrium between the CoV replication and transcription. CONCLUSION: The replication and transcription of CoVs are regulated by a negative feedback mechanism that influences the persistence of CoVs in hosts. Our findings enrich fundamental knowledge in the field of gene expression and its regulation, and provide new clues for future studies. One important clue is that nsp15 may be an important and ideal target for the development of drugs (e.g., uridine derivatives) against CoVs.

19.
Animal Model Exp Med ; 4(1): 2-15, 2021 03.
Article in English | MEDLINE | ID: covidwho-1122088

ABSTRACT

Background: Cardiovascular diseases (CVDs) and diabetes mellitus (DM) are top two chronic comorbidities that increase the severity and mortality of COVID-19. However, how SARS-CoV-2 alters the progression of chronic diseases remain unclear. Methods: We used adenovirus to deliver h-ACE2 to lung to enable SARS-CoV-2 infection in mice. SARS-CoV-2's impacts on pathogenesis of chronic diseases were studied through histopathological, virologic and molecular biology analysis. Results: Pre-existing CVDs resulted in viral invasion, ROS elevation and activation of apoptosis pathways contribute myocardial injury during SARS-CoV-2 infection. Viral infection increased fasting blood glucose and reduced insulin response in DM model. Bone mineral density decreased shortly after infection, which associated with impaired PI3K/AKT/mTOR signaling. Conclusion: We established mouse models mimicked the complex pathological symptoms of COVID-19 patients with chronic diseases. Pre-existing diseases could impair the inflammatory responses to SARS-CoV-2 infection, which further aggravated the pre-existing diseases. This work provided valuable information to better understand the interplay between the primary diseases and SARS-CoV-2 infection.


Subject(s)
COVID-19/complications , COVID-19/physiopathology , Cardiovascular Diseases/complications , Cardiovascular Diseases/physiopathology , Diabetes Complications/physiopathology , Animals , Comorbidity , Diabetes Mellitus , Disease Models, Animal , Male , Mice , SARS-CoV-2
20.
NPJ Sci Learn ; 6(1): 5, 2021 Mar 01.
Article in English | MEDLINE | ID: covidwho-1111985

ABSTRACT

Online education is important in the COVID-19 pandemic, but online exam at individual homes invites students to cheat in various ways, especially collusion. While physical proctoring is impossible during social distancing, online proctoring is costly, compromises privacy, and can lead to prevailing collusion. Here we develop an optimization-based anti-collusion approach for distanced online testing (DOT) by minimizing the collusion gain, which can be coupled with other techniques for cheating prevention. With prior knowledge of student competences, our DOT technology optimizes sequences of questions and assigns them to students in synchronized time slots, reducing the collusion gain by 2-3 orders of magnitude relative to the conventional exam in which students receive their common questions simultaneously. Our DOT theory allows control of the collusion gain to a sufficiently low level. Our recent final exam in the DOT format has been successful, as evidenced by statistical tests and a post-exam survey.

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