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1.
Kidney Int Rep ; 6(9): 2525, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1796885

ABSTRACT

[This corrects the article DOI: 10.1016/j.ekir.2020.07.010.][This corrects the article DOI: 10.1016/j.ekir.2021.07.022.].

2.
Kidney Int Rep ; 6(9): 2526-2531, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1796884

ABSTRACT

[This corrects the article DOI: 10.1016/j.ekir.2021.07.021.][This corrects the article DOI: 10.1016/j.ekir.2020.07.010.].

3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-325253

ABSTRACT

Coronavirus Disease 2019 (COVID-19) has caused great casualties and becomes almost the most urgent public health events worldwide. Computed tomography (CT) is a significant screening tool for COVID-19 infection, and automated segmentation of lung infection in COVID-19 CT images will greatly assist diagnosis and health care of patients. However, accurate and automatic segmentation of COVID-19 lung infections remains to be challenging. In this paper we propose a dilated dual attention U-Net (D2A U-Net) for COVID-19 lesion segmentation in CT slices based on dilated convolution and a novel dual attention mechanism to address the issues above. We introduce a dilated convolution module in model decoder to achieve large receptive field, which refines decoding process and contributes to segmentation accuracy. Also, we present a dual attention mechanism composed of two attention modules which are inserted to skip connection and model decoder respectively. The dual attention mechanism is utilized to refine feature maps and reduce semantic gap between different levels of the model. The proposed method has been evaluated on open-source dataset and outperforms cutting edges methods in semantic segmentation. Our proposed D2A U-Net with pretrained encoder achieves a Dice score of 0.7298 and recall score of 0.7071. Besides, we also build a simplified D2A U-Net without pretrained encoder to provide a fair comparison with other models trained from scratch, which still outperforms popular U-Net family models with a Dice score of 0.7047 and recall score of 0.6626. Our experiment results have shown that by introducing dilated convolution and dual attention mechanism, the number of false positives is significantly reduced, which improves sensitivity to COVID-19 lesions and subsequently brings significant increase to Dice score.

4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-324319

ABSTRACT

Background: Due to the increased risk of viral infection and the severe shortage of medical resources during the pandemic of COVID-19, most hospitals in the epidemic areas significantly reduced non-emergency admissions and services, if not closed. As a result, it has been difficult to treat cancer patients on time, which adversely affects their prognosis. To address this problem, cancer centers must develop a strategic plan to manage both inpatients and outpatients during the pandemic, provide them with the necessary treatment, and at the same time prevent the spread of the virus among patients, visitors and medical staff. Methods: : Based upon the epidemic situation in Zhejiang Province, China, the number of running non-emergency medical wards in the Zhejiang Cancer Hospital was gradually increased in a controlled manner. All staff of the hospital received COVID-19 preventive training and was provided with three different levels of protection according to the risks of their services. Only patients without a known history of SARS-CoV-2 contact were eligible to schedule an appointment. Body temperature was measured on all patients upon their arrival at the hospital. Chest CT image, blood cell counting and travel/contact history were investigated in patients with fever. Respiratory tract samples, such as sputum and throat swabs, from all patients, including those clinically suspected of SARS-CoV-2 infection, were collected for nucleic acid detection of SARS-CoV-2 before treatment. Results: : A total of 3697 inpatients and 416 outpatients seeking cancer treatment were enrolled from February 1 to April 3, 2020, in compliance with the hospital’s infection-control interventions. The clinicopathological parameters of the patients were summarized herein. 4237 samples from 4101 patients produced negative RNA testing results. Four clinically suspected patients all presented negative RNA test results and were excluded from the SARS-CoV-2 infection through follow-up retesting and monitoring. Seven patients with only N-gene positive results were retested, followed by CT scan and SARS-CoV-2 contact history investigation. All of them were finally diagnosed as non-infected patients. There was one outpatient who was confirmed positive by virus RNA test and then followed up. She might be an asymptomatic laboratory-confirmed case. During the study period, there was no SARS-CoV-2 infection among staff, patients and escorts of patients in the Zhejiang Cancer Hospital. Conclusion: This study suggested our infection-control interventions, including viral nucleic acid test, could be used as a reliable method to screen cancer patients in the area with moderate COVID-19 prevalence. Cancer may not be a high-risk factor of SARS-CoV-2 infection.

5.
Kidney Int Rep ; 6(9): 2525, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1433185

ABSTRACT

[This corrects the article DOI: 10.1016/j.ekir.2020.07.010.][This corrects the article DOI: 10.1016/j.ekir.2021.07.022.].

6.
Education Sciences ; 11(9):554, 2021.
Article in English | MDPI | ID: covidwho-1430812

ABSTRACT

The outbreak of COVID-19 worldwide in 2020 has posed tremendous challenges to higher education globally. Teaching English as a foreign language (TEFL) is among the many areas affected by the pandemic. The unexpected transition to online teaching has increased challenges for improving and/or retaining students’ language proficiency. WeChat, a popular social application in China, was widely used for TEFL at Chinese universities before COVID-19. However, it remains unclear whether the use of WeChat can facilitate Chinese university students’ English-language lexical proficiency during the pandemic. To fill this gap, the aim of the present study was two-fold: (1) it initially explored the relationship between the variables including students’ academic years, genders, and academic faculties/disciplines, and their lexical proficiency;and (2) it evaluated the effectiveness of a WeChat-assisted lexical learning (WALL) program in facilitating learning outcomes of English-language vocabulary. One hundred and thirty-three students at a university in Northern China participated in the WALL program for three weeks. As the results indicated, the independent variables had no correlation with the students’ lexical proficiency. More importantly, the students had a decline in the test scores after using the program, compared to their initial test scores. Moreover, the difference was reported to be medium. The findings further proposed questions on applying WeChat to vocabulary teaching in a large-scaled transition. The study is expected to provide insights for tertiary institutions, language practitioners, and student stakeholders to troubleshoot the potential problems regarding implementing WeChat-based TEFL pedagogies.

7.
BMJ ; 369: m2195, 2020 06 10.
Article in English | MEDLINE | ID: covidwho-1430181

ABSTRACT

OBJECTIVE: To examine the protective effects of appropriate personal protective equipment for frontline healthcare professionals who provided care for patients with coronavirus disease 2019 (covid-19). DESIGN: Cross sectional study. SETTING: Four hospitals in Wuhan, China. PARTICIPANTS: 420 healthcare professionals (116 doctors and 304 nurses) who were deployed to Wuhan by two affiliated hospitals of Sun Yat-sen University and Nanfang Hospital of Southern Medical University for 6-8 weeks from 24 January to 7 April 2020. These study participants were provided with appropriate personal protective equipment to deliver healthcare to patients admitted to hospital with covid-19 and were involved in aerosol generating procedures. 77 healthcare professionals with no exposure history to covid-19 and 80 patients who had recovered from covid-19 were recruited to verify the accuracy of antibody testing. MAIN OUTCOME MEASURES: Covid-19 related symptoms (fever, cough, and dyspnoea) and evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, defined as a positive test for virus specific nucleic acids in nasopharyngeal swabs, or a positive test for IgM or IgG antibodies in the serum samples. RESULTS: The average age of study participants was 35.8 years and 68.1% (286/420) were women. These study participants worked 4-6 hour shifts for an average of 5.4 days a week; they worked an average of 16.2 hours each week in intensive care units. All 420 study participants had direct contact with patients with covid-19 and performed at least one aerosol generating procedure. During the deployment period in Wuhan, none of the study participants reported covid-19 related symptoms. When the participants returned home, they all tested negative for SARS-CoV-2 specific nucleic acids and IgM or IgG antibodies (95% confidence interval 0.0 to 0.7%). CONCLUSION: Before a safe and effective vaccine becomes available, healthcare professionals remain susceptible to covid-19. Despite being at high risk of exposure, study participants were appropriately protected and did not contract infection or develop protective immunity against SARS-CoV-2. Healthcare systems must give priority to the procurement and distribution of personal protective equipment, and provide adequate training to healthcare professionals in its use.


Subject(s)
Coronavirus Infections/prevention & control , Health Personnel , Infection Control/instrumentation , Pandemics/prevention & control , Personal Protective Equipment/supply & distribution , Pneumonia, Viral/prevention & control , Adult , Betacoronavirus , COVID-19 , China , Coronavirus Infections/diagnosis , Cross-Sectional Studies , Female , Humans , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Intensive Care Units , Male , Middle Aged , Occupational Exposure/prevention & control , Pneumonia, Viral/diagnosis , SARS-CoV-2
8.
Nat Med ; 26(9): 1494, 2020 09.
Article in English | MEDLINE | ID: covidwho-1387438

ABSTRACT

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

9.
Kidney Int Rep ; 6(9): 2526-2531, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1385531

ABSTRACT

[This corrects the article DOI: 10.1016/j.ekir.2021.07.021.][This corrects the article DOI: 10.1016/j.ekir.2020.07.010.].

10.
Signal Transduct Target Ther ; 6(1): 197, 2021 05 18.
Article in English | MEDLINE | ID: covidwho-1233703

ABSTRACT

Our understanding of the protective immunity, particularly the long-term dynamics of neutralizing antibody (NAbs) response to SARS-CoV-2, is currently limited. We enrolled a cohort of 545 COVID-19 patients from Hubei, China, who were followed up up to 7 months, and determined the dynamics of NAbs to SARS-CoV-2 by using a surrogate virus neutralization test (sVNT). In our validation study, sVNT IC50 titers and the neutralization rate measured at a single dilution (1:20) were well correlated with FRNT titers (r = 0.85 and 0.84, respectively). The median time to seroconversion of NAbs was 5.5 days post onset of symptoms. The rate of positive sVNT was 52% in the first week, reached 100% in the third week, and remained above 97% till 6 months post onset. Quantitatively, NAbs peaked in the fourth week and only a quarter of patients had an estimated peak titer of >1000. NAbs declined with a half-time of 61 days (95% CI: 49-80 days) within the first two months, and the decay deaccelerated to a half-time of 104 days (95% CI: 86-130 days) afterward. The peak levels of NAbs were positively associated with severity of COVID-19 and age, while negatively associated with serum albumin levels. The observation that the low-moderate peak neutralizing activity and fast decay of NAbs in most naturally infected individuals called for caution in evaluating the feasibility of antibody-based therapy and vaccine durability. NAbs response positively correlated with disease severity, warning for the possibility of repeat infection in patients with mild COVID-19.


Subject(s)
Antibodies, Neutralizing , Antibodies, Viral , COVID-19 , SARS-CoV-2 , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/blood , COVID-19/immunology , Female , Humans , Male , Middle Aged , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Severity of Illness Index , Time Factors
11.
Clin Transl Immunology ; 10(3): e1260, 2021.
Article in English | MEDLINE | ID: covidwho-1120050

ABSTRACT

OBJECTIVES: A major COVID-19 vaccine strategy is to induce antibodies that prevent interaction between the Spike protein's receptor-binding domain (RBD) and angiotensin-converting enzyme 2 (ACE2). These vaccines will also induce T-cell responses. However, concerns were raised that aberrant vaccine-induced immune responses may exacerbate disease. We aimed to identify minimal epitopes on the RBD that would induce antibody responses that block the interaction of the RBD and ACE2 as a strategy leading to an effective vaccine with reduced risk of inducing immunopathology. METHODS: We procured a series of overlapping 20-amino acid peptides spanning the RBD and asked which were recognised by plasma from COVID-19 convalescent patients. Identified epitopes were conjugated to diphtheria-toxoid and used to vaccinate mice. Immune sera were tested for binding to the RBD and for their ability to block the interaction of the RBD and ACE2. RESULTS: Seven putative vaccine epitopes were identified. Memory B-cells (MBCs) specific for one of the epitopes were identified in the blood of convalescent patients. When used to vaccinate mice, six induced antibodies that bound recRBD and three induced antibodies that could partially block the interaction of the RBD and ACE2. However, when the sera were combined in pairs, we observed significantly enhanced inhibition of binding of RBD to ACE2. Two of the peptides were located in the main regions of the RBD known to contact ACE2. Of significant importance to vaccine development, two of the peptides were in regions that are invariant in the UK and South African strains. CONCLUSION: COVID-19 convalescent patients have SARS-CoV-2-specific antibodies and MBCs, the specificities of which can be defined with short peptides. Epitope-specific antibodies synergistically block RBD-ACE2 interaction.

12.
BMC Cancer ; 20(1): 1194, 2020 Dec 07.
Article in English | MEDLINE | ID: covidwho-962804

ABSTRACT

BACKGROUND: Due to the increased risk of viral infection and the severe shortage of medical resources during the pandemic of COVID-19, most hospitals in the epidemic areas significantly reduced non-emergency admissions and services, if not closed. As a result, it has been difficult to treat cancer patients on time, which adversely affects their prognosis. To address this problem, cancer centers must develop a strategic plan to manage both inpatients and outpatients during the pandemic, provide them with the necessary treatment, and at the same time prevent the spread of the virus among patients, visitors and medical staff. METHODS: Based upon the epidemic situation in Zhejiang Province, China, the number of running non-emergency medical wards in the Zhejiang Cancer Hospital was gradually increased in a controlled manner. All staff of the hospital received COVID-19 preventive training and was provided with three different levels of protection according to the risks of their services. Only patients without a known history of SARS-CoV-2 contact were eligible to schedule an appointment. Body temperature was measured on all patients upon their arrival at the hospital. Chest CT image, blood cell counting and travel/contact history were investigated in patients with fever. Respiratory tract samples, such as sputum and throat swabs, from all patients, including those clinically suspected of SARS-CoV-2 infection, were collected for nucleic acid detection of SARS-CoV-2 before treatment. RESULTS: A total of 3697 inpatients and 416 outpatients seeking cancer treatment were enrolled from February 1 to April 3, 2020, in compliance with the hospital's infection-control interventions. The clinicopathological parameters of the patients were summarized herein. 4237 samples from 4101 patients produced negative RNA testing results. Four clinically suspected patients all presented negative RNA test results and were excluded from the SARS-CoV-2 infection through follow-up retesting and monitoring. Seven patients with only N-gene positive results were retested, followed by CT scan and SARS-CoV-2 contact history investigation. All of them were finally diagnosed as non-infected patients. There was one outpatient who was confirmed positive by virus RNA test and then followed up. She might be an asymptomatic laboratory-confirmed case. During the study period, there was no SARS-CoV-2 infection among staff, patients and escorts of patients in the Zhejiang Cancer Hospital. CONCLUSION: This study suggested our infection-control interventions, including viral nucleic acid test, could be used as a reliable method to screen cancer patients in the area with moderate COVID-19 prevalence. Cancer may not be a high-risk factor of SARS-CoV-2 infection.


Subject(s)
COVID-19/epidemiology , Disease Management , Neoplasms/diagnosis , Pandemics , Adolescent , Adult , China/epidemiology , Female , Humans , Male , Middle Aged , Neoplasms/therapy , Patients , Young Adult
14.
Nat Med ; 26(8): 1193-1195, 2020 08.
Article in English | MEDLINE | ID: covidwho-541699

ABSTRACT

Detection of asymptomatic or subclinical novel human coronavirus SARS-CoV-2 infection is critical for understanding the overall prevalence and infection potential of COVID-19. To estimate the cumulative prevalence of SARS-CoV-2 infection in China, we evaluated the host serologic response, measured by the levels of immunoglobulins M and G in 17,368 individuals, in the city of Wuhan, the epicenter of the COVID-19 pandemic in China, and geographic regions in the country, during the period from 9 March 2020 to 10 April 2020. In our cohorts, the seropositivity in Wuhan varied between 3.2% and 3.8% in different subcohorts. Seroposivity progressively decreased in other cities as the distance to the epicenter increased. Patients who visited a hospital for maintenance hemodialysis and healthcare workers also had a higher seroprevalence of 3.3% (51 of 1,542, 2.5-4.3%, 95% confidence interval (CI)) and 1.8% (81 of 4,384, 1.5-2.3%, 95% CI), respectively. More studies are needed to determine whether these results are generalizable to other populations and geographic locations, as well as to determine at what rate seroprevalence is increasing with the progress of the COVID-19 pandemic. Serologic surveillance has the potential to provide a more faithful cumulative viral attack rate for the first season of this novel SARS-CoV-2 infection.


Subject(s)
Antibodies, Viral/blood , Coronavirus Infections/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Pneumonia, Viral/blood , Antibodies, Viral/immunology , Betacoronavirus/pathogenicity , COVID-19 , China/epidemiology , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Female , Health Personnel , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Male , Middle Aged , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , SARS-CoV-2 , Seroepidemiologic Studies
15.
Preprint in English | medRxiv | ID: ppmedrxiv-20026872

ABSTRACT

The authors have withdrawn their manuscript whilst they perform additional experiments to test some of their conclusions further. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

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