[Impacts of COVID-19 Lockdown on Air Quality in Shenzhen in Spring 2022].

The short-term reduction of air pollutant emissions is an important emergency control measure for avoiding air pollution exceedances in Chinese cities. However, the impacts of short-term emission reductions on the air qualities in southern Chinese cities in spring has not been fully explored. We analyzed the changes in air quality in Shenzhen, Guangdong before, during, and after a city-wide lockdown associated with COVID-19 control during March 14 to 20, 2022. Stable weather conditions prevailed before and during the lockdown, such that local air pollution was strongly affected by local emissions. In-situ measurements and WRF-GC simulations over the Pearl River Delta (PRD) both showed that, due to reductions in traffic emissions during the lockdown, the concentrations of nitrogen dioxide (NO2), respirable particulate matter (PM10), and fine particulate matters (PM2.5) in Shenzhen decreased by (-26±9.5)%, (-28±6.4)%, and (-20±8.2)%, respectively. However, surface ozone (O3) concentration did not change significantly[(-1.0±6.5)%]. TROPOMI satellite observations of formaldehyde and nitrogen dioxide column concentrations indicated that the ozone photochemistry in the PRD in spring 2022 was mainly controlled by the volatile organic compound (VOCs) concentrations and was not sensitive to the reduction in nitrogen oxide (NOx) concentrations. Reduction in NOx may even have increased O3, because the titration of O3 by NOx was weakened. Due to the small spatial-temporal extent of emission reductions, the air quality effects caused by this short-term urban-scale lockdown were weaker than the air quality effects across China during the widespread COVID-19 lockdown in 2020. Future air quality management in South China cities should consider the impacts of NOx emission reduction on ozone and focus on the co-reduction scenarios of NOx and VOCs.

Inequitable access to general and behavioral healthcare in the US during the COVID-19 pandemic: A role for telehealth?

Wide-ranging effects of the COVID-19 pandemic have led to increased psychological distress and alcohol consumption, and disproportionate hardship for disadvantaged groups. Early in the pandemic, telehealth services were expanded to maintain healthcare access amidst lockdowns, medical office closures, and fear of infection. This study examines general and behavioral healthcare access and disparities during the first year of the pandemic. Data are from the 2019-2020 US National Alcohol Survey (collected February 2019 to April 2020) and its COVID follow-up survey conducted January 30 to March 28, 2021 (N = 1819). General and behavioral healthcare-related outcomes were assessed at follow-up, and included perceived need for and receipt of care, delayed care, and use of telehealth since April 1, 2020. Results indicate that the majority of respondents with perceived need for healthcare received some behavioral healthcare (reported by 63%) and particularly general healthcare (88%), but nearly half (48%) delayed needed care. Delays were mostly due to COVID-related reasons, but cost barriers also were common and significantly impeded care-seeking by uninsured persons, young adults, rural residents, and persons whose employment was reduced by the pandemic. Disparities in the receipt of healthcare were pronounced for Hispanic/Latinx (vs. White) and lower-income (vs. higher-income) groups (AORs <0.37, p's < 0.05). Notably, telehealth was commonly used by Hispanic/Latinx and lower-income groups for general and particularly behavioral healthcare. Results suggest that telehealth has provided an important bridge to healthcare for certain medically underserved groups during the pandemic, and may be vital to future efforts to increase equity in healthcare access.

Chinese college students COVID-19 phobia and negative moods: Moderating effects of physical exercise behavior.

Objective: We investigated the effects of COVID-19 fear on negative moods among college students, and assessed the efficacy of physical exercise behavior as a moderator variable. Methods: This was a cross-sectional study. Students from three colleges and universities in Shangqiu City, Henan Province and Yangzhou City, Jiangsu Province were enrolled in this study, which was performed during the COVID-19 pandemic using an online questionnaire. A total of 3,133 college students completed the questionnaire. Measurement tools included the COVID-19 Phobia Scale (C19P-S), Depression-Anxiety-Stress Self-Rating Scale (DASS), and the Physical Activity Behavior Scale (PARS-3). Results: During the COVID-19 pandemic, the rates of depression, anxiety, and stressful negative moods among college students were 35.5, 65.5, and 10.95%, respectively; there was a positive correlation between COVID-19 fear and negative moods among college students (r = 0.479, p < 0.001), which was negatively correlated with physical exercise behavior (r = -0.4, p < 0.001); the regulating effects of physical exercise behavior were significant (ΔR2 = 0.04, p < 0.001). Conclusion: The rate of negative moods among college students is high, and the fear for COVID-19 is one of the key factors that lead to negative moods. Physical exercise can modulate the impact of COVID-19 fear among college students on negative moods. Studies should elucidate on mental health issues among different populations during the COVID-19 pandemic.

Preparation and identification of monoclonal antibodies against nucleocapsid protein of novel coronavirus (SARS-CoV-2)

[Objective] At present, a novel emerging Coronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has caused an epidemic in the world, seriously threatening human life and health. To establish a basis for a rapid detection method for SARS-CoV-2, the monoclonal antibodies targeting nucleocapsid (N)gene were prepared and identified in this study. [Methods] BA LB/c mice were immunized with purified SARS-CoV-2 N recombinant protein. After four times of immunization. the spleen cells of the mice were fused with SP2/0 myeloma cells. The positive hybridoma cell lines stably secreting monoclonal anti-body were screened through ELISA, and the reactivity of the monoclonal antibody was further determined by western blot and indirect immunofluorescence assay. [Results] After three subclones, two hybridoma cell lines designated as 2D11 and 8G6 were obtained. and the prepared antibodies showed good reactivity with the eukaryotic expression of SARS-CoV-2 N protein. [Conclusion] The monoclonal antibody manufactured in this study can be used for SARS-CoV-2 detection.

Association between fear of COVID-19 and hoarding behavior during the outbreak of the COVID-19 pandemic: The mediating role of mental health status

Hoarding behavior can effectively improve people's ability to resist risks, so as to reduce the negative effects of risks. However, excessive hoarding behavior will seriously reduce people's quality of life. The COVID-19 pandemic can cause excessive hoarding in a large number of people in a short period of time, and also cause a series of economic problems such as social material shortage. It is unclear how hoarding levels are linked to fear and negative emotions caused by COVID-19 among people of different educational backgrounds and social status. The purpose of this study was to explore the relationship between fear of COVID-19 and hoarding behavior in different populations in school and social contexts, as well as the mediating role of negative emotions and the moderating role of subjective/objective social status and education level in this process. An online cross-sectional survey was conducted in various provinces in China in January 2022. Demographic information, the MacArthur Scale of Subjective Social Status, the Fear of COVID-19 scale, the Depression Anxiety Stress-21, and the Saving Inventory-Revised were used to evaluate the severity of individual hoarding symptoms, the frequency of hoarding, the degree of fear, and the negative emotions (depression, anxiety, stress) caused by COVID-19. Research data showed that fear of COVID-19 was significantly correlated with hoarding behavior (p < 0.05). Fear of COVID-19 was significantly lower in the student sample than in the nonstudent sample (p < 0.05). Negative emotions played a mediating role in the relationship between fear of COVID-19 and hoarding behavior (p < 0.05). Educational and economic levels moderated this process, but social status did not. Compared with the student sample, educational background and income had less of a moderating effect on the depression, anxiety, and stress caused by fear of COVID-19 in the nonstudent sample. However, these factors had a more regulative effect on the clutter and excessive acquisition behavior caused by depression, anxiety, and stress, although not on difficulty discarding. These findings suggest that reduce negative emotions in the population, improve cognitive levels, and provide financial support from governments may be effective ways to reduce hoarding symptoms.

Behaviour in public open spaces: A systematic review of studies with quantitative research methods

Public open spaces are important assets that play a significant role in city lives, based on which a great number of behaviour-based studies are being conducted. These studies often use one or more case studies to observe people's preferences and usage habits and to investigate their influencing factors such as outdoor thermal comfort, environmental conditions, urban configuration, and local settings. Because the subject is complex and falls within the purview of multiple academic disciplines, it is a challenging task to understand the current status and development trends of existing studies. To fill this gap, this article presents a systematic review of quantitative evidence-based behaviour studies in public open spaces. Following the PRISMA method and searching using eight academic search engines, full texts of 116 research articles have been included for this review. The main contributions of this review are that: (1) it proposed a relatively complete system that categorizes people's behaviour in public open spaces;(2) it introduced outdoor subjective influencing procedure including behaviour, feeling and health impacts;(3) the review illustrated the distribution of existing research as well as research trends;and finally (4) the article also timely discussed the influence of the COVID-19 on people's behaviour in public open spaces. The authors consider this article to be useful as it can facilitate further behaviour-based studies in public open spaces. With a robust classification and future trend discussion of factors associated, fellow researchers, urban designers, city managers, and policymakers are easier to integrate and use the knowledge learned.

A Systematic Review of Objective Factors Influencing Behavior in Public Open Spaces.

As a significant part of outdoor built-environment, public open spaces are closely associated with people's daily lives. Studies of outdoor behavior in these spaces can shed light on users' environmental perceptions and contribute to the promotion of physiological and psychological health. Many recent studies are case studies focused where observations, surveys and interviews have been conducted to understand the factors influencing people's behavior on one or few sites or city environments. There have been few reviews related to this topic, and none have been based on the systematic understanding of influencing factors. This paper presents a systematic review of interactions between behavior and the built environment in public open spaces, and highlights the impacts of diverse and objective influencing factors. Followed the rules of PRISMA method (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), 109 papers published in 2000-2021 were selected and reviewed. The distribution of the studied interactions is analyzed, and the impacts of four distinct factors: personal background, location and context, environmental component, and climate stimuli, are extracted, categorized, and specified. Moreover, outdoor health benefits are discussed based on which, crucial factors that require emphasis after the outbreak of COVID-19 are identified. Throughout this paper, behavioral influencing processes, including objective influencing factors, subjective feedback, and the relationships involved, are considered to provide a comprehensive picture. With the robust classification of existing factors, architects, urban designers, policy makers and fellow researches could be easier to get a more comprehensive trend from the past. This paper also provides guidance for future research, especially given that COVID-19 has created huge changes to outdoor needs and customary behavior. Systematic Review Registration: http://www.prisma-statement.org/.

Luteolin Potentially Treating Prostate Cancer and COVID-19 Analyzed by the Bioinformatics Approach: Clinical Findings and Drug Targets.

Coronavirus disease 2019 (COVID-19) is a serious epidemic, characterized by potential mutation and can bring about poor vaccine efficiency. It is evidenced that patients with malignancies, including prostate cancer (PC), may be highly vulnerable to the SARS-CoV-2 infection. Currently, there are no existing drugs that can cure PC and COVID-19. Luteolin can potentially be employed for COVID-19 treatment and serve as a potent anticancer agent. Our present study was conducted to discover the possible drug target and curative mechanism of luteolin to serve as treatment for PC and COVID-19. The differential gene expression of PC cases was determined via RNA sequencing. The application of network pharmacology and molecular docking aimed to exhibit the drug targets and pharmacological mechanisms of luteolin. In this study, we found the top 20 up- and downregulated gene expressions in PC patients. Enrichment data demonstrated anti-inflammatory effects, where improvement of metabolism and enhancement of immunity were the main functions and mechanism of luteolin in treating PC and COVID-19, characterized by associated signaling pathways. Additional core drug targets, including MPO and FOS genes, were computationally identified accordingly. In conclusion, luteolin may be a promising treatment for PC and COVID-19 based on bioinformatics findings, prior to future clinical validation and application.

Luteolin Potentially Treating Prostate Cancer and COVID-19 Analyzed by the Bioinformatics Approach: Clinical Findings and Drug Targets

Coronavirus disease 2019 (COVID-19) is a serious epidemic, characterized by potential mutation and can bring about poor vaccine efficiency. It is evidenced that patients with malignancies, including prostate cancer (PC), may be highly vulnerable to the SARS-CoV-2 infection. Currently, there are no existing drugs that can cure PC and COVID-19. Luteolin can potentially be employed for COVID-19 treatment and serve as a potent anticancer agent. Our present study was conducted to discover the possible drug target and curative mechanism of luteolin to serve as treatment for PC and COVID-19. The differential gene expression of PC cases was determined via RNA sequencing. The application of network pharmacology and molecular docking aimed to exhibit the drug targets and pharmacological mechanisms of luteolin. In this study, we found the top 20 up- and downregulated gene expressions in PC patients. Enrichment data demonstrated anti-inflammatory effects, where improvement of metabolism and enhancement of immunity were the main functions and mechanism of luteolin in treating PC and COVID-19, characterized by associated signaling pathways. Additional core drug targets, including MPO and FOS genes, were computationally identified accordingly. In conclusion, luteolin may be a promising treatment for PC and COVID-19 based on bioinformatics findings, prior to future clinical validation and application.

Mental health and drinking to cope in the early COVID period: Data from the 2019-2020 US National Alcohol Survey.

BACKGROUND: Studies show drinking to cope and mental health problems have increased during the COVID-19 pandemic, however, their samples have been limited by convenience sampling or lack of a pre-pandemic measure. We examined the early impact of the COVID-19 pandemic on mental health, drinking to cope and their association using a probability-based sample of the US adult population. METHODS: Data was drawn from the probability samples of the 2019-2020 National Alcohol Survey (N = 7,233) to examine differences in drinking to cope and symptoms of depression and anxiety. Analyses compared participants who responded to the survey just prior to the widespread onset of the pandemic to those who responded after March 2020, in the total sample and by sex. RESULTS: Respondents in the early- vs. pre-COVID-19 period had a 1.48 higher odds (p = 0.03) of higher agreement with drinking to forget one's worries and problems, with a significant association observed among women only. Respondents with symptoms of depression and anxiety had a 2.94 and 1.56 higher odds, respectively, of higher agreement with drinking to forget one's worries. We observed significant associations between early- vs. pre-COVID-19 period, depression and anxiety symptoms, and drinking to forget one's worries among women only; however, moderation by sex in the total sample was not statistically significant. CONCLUSIONS: We observed higher prevalence of depression and anxiety symptoms and greater drinking to forget worries in the early months of COVID restrictions relative to the period just prior, with some effects more prominent among women. These observations call for sustained monitoring of and support for the mental health of the general population, and of women in particular during the course of the pandemic.

Efficacy and Safety of Anticoagulation Treatment in COVID-19 Patient Subgroups Identified by Clinical-Based Stratification and Unsupervised Machine Learning: A Matched Cohort Study

Objective: To explore the efficacy of anticoagulation in improving outcomes and safety of Coronavirus disease 2019 (COVID-19) patients in subgroups identified by clinical-based stratification and unsupervised machine learning. Methods: This single-center retrospective cohort study unselectively reviewed 2,272 patients with COVID-19 admitted to the Tongji Hospital between Jan 25 and Mar 23, 2020. The association between AC treatment and outcomes was investigated in the propensity score (PS) matched cohort and the full cohort by inverse probability of treatment weighting (IPTW) analysis. Subgroup analysis, identified by clinical-based stratification or unsupervised machine learning, was used to identify sub-phenotypes with meaningful clinical features and the target patients benefiting most from AC. Results: AC treatment was associated with lower in-hospital death risk either in the PS matched cohort or by IPTW analysis in the full cohort. A higher incidence of clinically relevant non-major bleeding (CRNMB) was observed in the AC group, but not major bleeding. Clinical subgroup analysis showed that, at admission, severe cases of COVID-19 clinical classification, mild acute respiratory distress syndrome (ARDS) cases, and patients with a D-dimer level ≥0.5 μg/mL, may benefit from AC. During the hospital stay, critical cases and severe ARDS cases may benefit from AC. Unsupervised machine learning analysis established a four-class clustering model. Clusters 1 and 2 were non-critical cases and might not benefit from AC, while clusters 3 and 4 were critical patients. Patients in cluster 3 might benefit from AC with no increase in bleeding events. While patients in cluster 4, who were characterized by multiple organ dysfunction (neurologic, circulation, coagulation, kidney and liver dysfunction) and elevated inflammation biomarkers, did not benefit from AC. Conclusions: AC treatment was associated with lower in-hospital death risk, especially in critically ill COVID-19 patients. Unsupervised learning analysis revealed that the most critically ill patients with multiple organ dysfunction and excessive inflammation might not benefit from AC. More attention should be paid to bleeding events (especially CRNMB) when using AC.

Antiviral Activities of Carbazole Derivatives against Porcine Epidemic Diarrhea Virus In Vitro.

Porcine epidemic diarrhea virus (PEDV), an enteric coronavirus, causes neonatal pig acute gastrointestinal infection with a characterization of severe diarrhea, vomiting, high morbidity, and high mortality, resulting in tremendous damages to the swine industry. Neither specific antiviral drugs nor effective vaccines are available, posing a high priority to screen antiviral drugs. The aim of this study is to investigate anti-PEDV effects of carbazole alkaloid derivatives. Eighteen carbazole derivatives (No.1 to No.18) were synthesized, and No.5, No.7, and No.18 were identified to markedly reduce the replication of enhanced green fluorescent protein (EGFP) inserted-PEDV, and the mRNA level of PEDV N. Flow cytometry assay, coupled with CCK8 assay, confirmed No.7 and No.18 carbazole derivatives displayed high inhibition effects with low cell toxicity. Furthermore, time course analysis indicated No.7 and No.18 carbazole derivatives exerted inhibition at the early stage of the viral life cycle. Collectively, the analysis underlines the benefit of carbazole derivatives as potential inhibitors of PEDV, and provides candidates for the development of novel therapeutic agents.

What will it take to end AIDS in Asia and the Pacific region by 2030?

The 2016 global commitments towards ending the AIDS epidemic by 2030 require the Asia-Pacific region to reach the Fast-Track targets by 2020. Despite early successes, the region is well short of meeting these targets. The overall stalled progress in the HIV response has been further undermined by rising new infections among young key populations and the unprecedented COVID-19 pandemic. This paper examines the HIV situation, assesses the gaps, and analyses what it would take the region to end AIDS by 2030. Political will and commitments for ending AIDS must be reaffirmed and reinforced. Focused regional strategic direction that answers the specific regional context and guides countries to respond to their specific needs must be put in place. The region must harness the power of innovative tools and technology in both prevention and treatment. Community activism and meaningful community engagement across the spectrum of HIV response must be ensured. Punitive laws, stigma, and discrimination that deter key populations and people living with HIV from accessing health services must be effectively tackled. The people-centred public health approach must be fully integrated into national universal health coverage while ensuring domestic resources are available for community-led service delivery. The region must utilise its full potential and draw upon lessons that have been learnt to address common challenges of the HIV and COVID-19 pandemics and achieve the goal of ending AIDS by 2030, in fulfillment of the United Nations' Sustainable Development Goals.

Etiological and epidemiological characteristics of severe acute respiratory infection caused by multiple viruses and Mycoplasma pneumoniae in adult patients in Jinshan, Shanghai: A pilot hospital-based surveillance study.

BACKGROUND: Severe acute respiratory infection (SARI) results in a tremendous disease burden worldwide. Available research on active surveillance among hospitalized adult patients suffering from SARI in China is limited. This pilot study aimed to identify associated etiologies and describe the demographic, epidemiological and clinical profiles of hospitalized SARI patients aged over 16 years in Jinshan, Shanghai. METHODS: Active surveillance was conducted at 1 sentinel hospital in Jinshan district, Shanghai, from April 2017 to March 2018. Hospitalized SARI patients aged over 16 years old were enrolled, and nasopharyngeal swabs were collected within 24 hours of admission and tested for multiple respiratory viruses (including 18 common viruses) and Mycoplasma pneumoniae with real-time polymerase chain reaction. Demographic, epidemiological and clinical information was obtained from case report forms. RESULTS: In total, 397 SARI patients were enrolled; the median age was 68 years, and 194 (48.9%) patients were male. A total of 278 (70.0%) patients had at least one underlying chronic medical condition. The most frequent symptoms were cough (99.2%) and sputum production (88.4%). The median duration of hospitalization was 10 days. A total of 250 infection patients (63.0%) were positive for at least one pathogen, of whom 198 (49.9%) were positive for a single pathogen and 52 (13.1%) were positive for multiple pathogens. The pathogens identified most frequently were M. pneumoniae (23.9%, 95/397), followed by adenovirus (AdV) (11.6%, 46/397), influenza virus A/H3N2 (Flu A/H3N2) (11.1%, 44/397), human rhinovirus (HRhV) (8.1%, 32/397), influenza virus B/Yamagata (Flu B/Yamagata) (6.3%, 25/397), pandemic influenza virus A/H1N1 (Flu A/pH1N1) (4.0%, 16/397), parainfluenza virus (PIV) type 1 (2.0%, 8/397), human coronavirus (HCoV) type NL63 (2.0%, 8/397), HCoV 229E (1.5%, 6/397), HCoV HKU1 (1.5%, 6/397), PIV 3 (1.5%, 6/397), human metapneumovirus (HMPV) (1.5%, 6/397), PIV 4 (1.3%, 5/397), HCoV OC43 (1.0%, 4/397), influenza virus B/Victoria (Flu B/Victoria) (0.5%, 2/397), respiratory syncytial virus (RSV) type B (0.5%, 2/397), and human bocavirus (HBoV) (0.3%, 1/397). The seasonality of pathogen-confirmed SARI patients had a bimodal distribution, with the first peak in the summer and the second peak in the winter. Statistically significant differences were observed with respect to the rates of dyspnea, radiographically diagnosed pneumonia and the presence of at least one comorbidity in patients who were infected with only M. pneumoniae, AdV, HRhV, Flu A/H3N2, Flu A /pH1N1 or Flu B/Yamagata. The differences in the positivity rates of the above 6 pathogens among the different age groups were nonsignificant. CONCLUSIONS: M. pneumoniae, AdV and Flu A/H3N2 were the main pathogens detected in hospitalized SARI patients aged over 16 years old in Jinshan district, Shanghai. Our findings highlight the importance of sustained multipathogen surveillance among SARI patients in sentinel hospitals, which can provide useful information on SARI etiologies, epidemiology, and clinical characteristics.

The Psychological Responses and Associated Factors of Chinese College Students During COVID-19 Outbreak in February (preprint)

BackgroundThe novel coronavirus pneumonia (COVID-19) is a highly contagious and highly pathogenic disease caused by a novel coronavirus（SARS-CoV-2）and has become pandemic within a short period of time. The epidemic has brought not only the risk of death from infection but also unbearable psychological pressure. College students as a special group, their mental health status need to be studied during the outbreak of COVID-19.MethodsWe used the Self-Rating Anxiety Scale (SAS), Self-Rating Depression Scale (SDS), and the compulsive behavior part of the Yale-Brown Obsessive-Compulsive Scale (YBOCS), combined with demographic information, using online questionnaires to research, and the study was conducted between February 21 and 24, 2020. A total of 2270 valid questionnaires were collected, the respondents of these questionnaires included 563 medical students and 1707 non-medical students. We separately analyzed the mental health status of medical and non-medical students during the outbreak of COVID-19.ResultsOf the 563 medical students, 20 (3.55%) students had anxiety symptoms, and 57 (10.12%) students had depressive symptoms. Gender, PMH, compulsive behavior, and regularity of daily life during the epidemic outbreak were correlated with their anxiety symptoms and age, PMH, compulsive behavior, and regularity of daily life during the epidemic outbreak were associated with their depressive symptoms. Of the 1707 non-medical students, 66 (3.87%) students had anxiety symptoms, and 180 (10.54%) students had depressive symptoms. Gender, contact history of similar infectious disease, PMH, compulsive behavior, regularity of daily life and exercise during the epidemic outbreak and concern on COVID-19 were correlated with their anxiety symptoms and contact history of similar infectious disease, PMH, compulsive behavior, regularity of daily life and exercise during the epidemic outbreak and concern on COVID-19 were associated with their depressive symptoms.ConclusionsResults indicated that gender, age, contact history of similar infectious disease, past medical history (PMH), compulsive behavior, regularity of daily life, and exercise during the epidemic outbreak are the key factors making college students anxious or depressed. The results provided a theoretical basis for relevant interventions; it is also essential for medical education and public health epidemic prevention.

A CRISPR-Cas12a-based specific enhancer for more sensitive detection of SARS-CoV-2 infection.

BACKGROUND: Real-time reverse transcription-PCR (rRT-PCR) has been the most effective and widely implemented diagnostic technology since the beginning of the COVID-19 pandemic. However, fuzzy rRT-PCR readouts with high Ct values are frequently encountered, resulting in uncertainty in diagnosis. METHODS: A Specific Enhancer for PCR-amplified Nucleic Acid (SENA) was developed based on the Cas12a trans-cleavage activity, which is specifically triggered by the rRT-PCR amplicons of the SARS-CoV-2 Orf1ab (O) and N fragments. SENA was first characterized to determine its sensitivity and specificity, using a systematic titration experiment with pure SARS-CoV-2 RNA standards, and was then verified in several hospitals, employing a couple of commercial rRT-PCR kits and testing various clinical specimens under different scenarios. FINDINGS: The ratio (10 min/5 min) of fluorescence change (FC) with mixed SENA reaction (mix-FCratio) was defined for quantitative analysis of target O and N genes, and the Limit of Detection (LoD) of mix-FCratio with 95% confidence interval was 1.2≤1.6≤2.1. Totally, 295 clinical specimens were analyzed, among which 21 uncertain rRT-PCR cases as well as 4 false negative and 2 false positive samples were characterized by SENA and further verified by next-generation sequencing (NGS). The cut-off values for mix-FCratio were determined as 1.145 for positive and 1.068 for negative. INTERPRETATION: SENA increases both the sensitivity and the specificity of rRT-PCR, solving the uncertainty problem in COVID-19 diagnosis and thus providing a simple and low-cost companion diagnosis for combating the pandemic. FUNDING: Detailed funding information is available at the end of the manuscript.

Application of cell surface-fluorescence immunosorbent assay in rapid screening of a hybridoma secreting monoclonal antibodyagainst PEDV N protein

To verify the effect of cell surface-fluorescence immunosorbent assay (CSFIA) on screening the highly active hybridoma cells, 6-8 week-old female BALB/c mice were immunized with recombinant porcine epidemic diarrhea virus (PEDV) N protein, and then spleen cells isolated from mice were fused with SP2/0 cells to generate hybridomas. The hybridomas secreting MAbs against PEDV N protein were screened by indirect ELISA and cell surface-fluorescence immunosorbent assay (CSFIA), respectively. The titer of MAbs secreted by each hybridoma was determined. Using these methods, two strains of hybridoma celllines secreting MAbs against PEDV N protein, designated as 3D3 and 1B1, respectively, were obtained and characterized. The results showed that the titer of 1B1 produced by CSFIA was 10 times higher than that of 3D3, and the preparation time was shortened by about 30 days on account of the direct selection of hybridoma through the fluorescence intensity without the need of multiple subcloning procedures. This study indicates that CSFIA is a powerful method to screen the hybridomas secreting higher titer MAb in a rapid one-step process, which would be valuable alternative for a rapid production of MAbs.