[Improvement of China's legal system for public health emergency management from the perspective of lifecycle management].

A crucial lesson gained through the pandemic preparedness and response to COVID-19 is that all measures for epidemic control must be law-based. The legal system is related not only to public health emergency management per se but also to all aspects of the institutional supporting system throughout the lifecycle. Based on the lifecycle emergency management model, this article analyses the problems of the current legal system and the potential solutions. It is suggested that the lifecycle emergency management model shall be followed to establish a more comprehensive public health legal system and to gather the intelligence and consensus of experts with different expertise, including epidemiologists, sociologists, economists, jurist and others, which will collaboratively promote the science-based legislation in the field of epidemic preparedness and response for the establishment of a comprehensive legal system for public health emergency management and with Chinese characteristics.

The effect of mortality salience on consumers' preference for experiential purchases and its mechanism

Inevitably, consumers will be exposed to death-related information in their daily lives. For example, they are informed about deaths and injuries caused by accidents, terrorism and disasters on social media. They may also encounter the experiences of deceased friends and relatives or the news of unfortunate strangers. Especially in the context of the COVID-19 pandemic, consumers are more frequently exposed to death cues. Researches have shown that consumers' decision-makings and purchasing behaviors shift when dealing with death threats. Compared to material consumption, experiential consumption delivers greater and persistent well-being and it is emerging as an extremely important consumption pattern. It is unclear, however, whether these mortality cues will exert positive or negative effects on consumers' preference for experiential purchases. Based on the meaning maintenance model, 4 studies were conducted to examine how mortality salience influences consumers' preference for experiential purchases. In Study 1a and Study 1b, we experimentally manipulated mortality salience and examined its effect on consumers' preference for experiential purchases. Study 1a (N = 140) was a single factor (mortality salience) between-subjects design, participants were randomly assigned to different groups to imagine about incurable infectious disease or dental surgery. Participants in Study 1b (N = 252) were instructed to write about death or dental pain. Study 2 (N =219) was designed to test the mediating role of meaning in life. Participants were required to read a news report concerning traffic accident or dental surgery, and then finish the Meaning in Life Questionnaire. Study 3 (N = 166) was a 2 (mortality salience vs. control condition) × 2 (social support: high level vs. low level) between-subjects design. Participants were provided a news report pertaining to the global fatalities under the COVID-19 pandemic in mortality salience condition, and pertaining to global tourism during the pandemic period in the control condition. Social support was manipulated by writing in detail a difficult situation "in which your family or friends accompanied you", or "in which you had to face all by yourself". Additionally, we used a single-paper meta-analysis (SPM) to document a robust effect across all studies. The main results of this study are as follows: (1) Exposed to mortality salience will lead to stronger preference for experiential purchases. (2) The effects seem to be driven by meaning in life, whereby exposure to mortality salience undermines consumers' meaning in life, and consumers will gravitate towards experiential consumption to enhance their impaired meaning. (3) Social support moderates the effect of mortality salience on meaning in life. Only when consumers received low level of social support, will mortality salience reduce their meaning in life. (4) Social support moderates the mediating effect of meaning in life on mortality salience and preference for experiential purchases. Specifically, meaning in life mediates the effect of mortality salience on preference for experiential purchases only when consumers received low social support. To enhance the overall validity, we performed a single-paper meta-analysis (SPM) on the four studies. The SPM showed that consumers had greater preference of experiential purchase when exposed to mortality salience (Estimate β = 0.30, SE = 0.07, z = 4.178, p < 0.001), which strengthened the robustness of our general conclusion. This research yields practical implications by demonstrating that mortality salience exerts positive effect on consumers' preference for experiential purchases, which enables us to identify the changes in consumption patterns and mindset under the pandemic, providing references for marketing and promotion strategies. © Science Press.

The effect of mortality salience on consumers' preference for experiential purchases and its mechanism

Inevitably, consumers will be exposed to death-related information in their daily lives. For example, they are informed about deaths and injuries caused by accidents, terrorism and disasters on social media. They may also encounter the experiences of deceased friends and relatives or the news of unfortunate strangers. Especially in the context of the COVID-19 pandemic, consumers are more frequently exposed to death cues. Researches have shown that consumers' decision-makings and purchasing behaviors shift when dealing with death threats. Compared to material consumption, experiential consumption delivers greater and persistent well-being and it is emerging as an extremely important consumption pattern. It is unclear, however, whether these mortality cues will exert positive or negative effects on consumers’ preference for experiential purchases. Based on the meaning maintenance model, 4 studies were conducted to examine how mortality salience influences consumers' preference for experiential purchases. In Study 1a and Study 1b, we experimentally manipulated mortality salience and examined its effect on consumers’ preference for experiential purchases. Study 1a (N = 140) was a single factor (mortality salience) between-subjects design, participants were randomly assigned to different groups to imagine about incurable infectious disease or dental surgery. Participants in Study 1b (N = 252) were instructed to write about death or dental pain. Study 2 (N =219) was designed to test the mediating role of meaning in life. Participants were required to read a news report concerning traffic accident or dental surgery, and then finish the Meaning in Life Questionnaire. Study 3 (N = 166) was a 2 (mortality salience vs. control condition) × 2 (social support: high level vs. low level) between-subjects design. Participants were provided a news report pertaining to the global fatalities under the COVID-19 pandemic in mortality salience condition, and pertaining to global tourism during the pandemic period in the control condition. Social support was manipulated by writing in detail a difficult situation "in which your family or friends accompanied you", or "in which you had to face all by yourself". Additionally, we used a single-paper meta-analysis (SPM) to document a robust effect across all studies. The main results of this study are as follows: (1) Exposed to mortality salience will lead to stronger preference for experiential purchases. (2) The effects seem to be driven by meaning in life, whereby exposure to mortality salience undermines consumers' meaning in life, and consumers will gravitate towards experiential consumption to enhance their impaired meaning. (3) Social support moderates the effect of mortality salience on meaning in life. Only when consumers received low level of social support, will mortality salience reduce their meaning in life. (4) Social support moderates the mediating effect of meaning in life on mortality salience and preference for experiential purchases. Specifically, meaning in life mediates the effect of mortality salience on preference for experiential purchases only when consumers received low social support. To enhance the overall validity, we performed a single-paper meta-analysis (SPM) on the four studies. The SPM showed that consumers had greater preference of experiential purchase when exposed to mortality salience (Estimate β = 0.30, SE = 0.07, z = 4.178, p < 0.001), which strengthened the robustness of our general conclusion. This research yields practical implications by demonstrating that mortality salience exerts positive effect on consumers' preference for experiential purchases, which enables us to identify the changes in consumption patterns and mindset under the pandemic, providing references for marketing and promotion strategies. © Science Press.

Preparation and preliminary application of antiserum against S protein of SARS-CoV-2

Objective To prepare antiserum against S protein of SARS-CoV-2 and preliminarily develop a method for determination of antigen content in inactivated SARS-CoV-2 vaccine. Methods Goats and rabbits were immunized with recombinant S protein of SARS-CoV-2, and the obtained antisera were determined for titer by indirect ELISA and neutralization assay and for specificity by Western blot, then purified by protein G resin affinity chro-matography. A sandwich ELISA for determination of antigen content of inactivated SARS-CoV-2 vaccine was developed by using purified goat antibody as capture antibody and purified rabbit antibody as detection antibody. Results The titer of antiserum of goats after immunization for 4 times reached 220 000 by ELISA and 1 536 by neutralization assay, while that of rabbits after immunization for 3 times reached 220 000 by ELISA and 4 096 by neutralization assay. Both goat and rabbit antibodies showed specific binding to the S protein of SARS-CoV-2. A double antibody sandwich ELISA method for determination of antigen content was successfully developed by using the purified antibodies, which showed a good linearity with a R2 value of more than 0. 99. Conclusion High titer goat and rabbit antisera against S protein of SARS-CoV-2 were prepared successfully, and double antibody sandwich ELISA method for determination of antigen content of inactivated SARS-CoV-2 vaccine was preliminarily developed. © 2021 Changchun Institute of Biological Products. All rights reserved.

Comparison of disinfection effects of different methods for nucleic acid pollution in 2019-nCoV

Objective: To evaluate the ability of different disinfection methods to remove nucleic acid pollution in 2019-nCoV so as to obtain the best removal scheme. Methods: 2019-nCoV positive quality control nucleic acid of 50 μL was applied to plastic, metal and glass with medical cotton swabs, respectively. After drying, we dropped 50 μL of 750 mL/L alcohol (ethanol), chlorine-containing disinfectant (2 000 mg/L and 5 500 mg/L), and PCR Cleaner, respectively. After 1 min, the contaminated area was wiped with medical cotton swabs and soaked in 300 μL of pure water. After shaking and mixing, 5 μL was taken as a template. The Ct values of ORF1ab and N genes and IC genes of internal standard fragment in the amplified target area of 2019-nCoV after wiping with different disinfection methods were compared to evaluate the effect of eliminating nucleic acid pollution, and each experiment was repeated for three times. Similarly, the effects of ultraviolet irradiation for 0, 1, 2, 3, 4, and 5 hours on the removal of nucleic acid pollution were compared. Results: After 2 000 mg/L and 5 500 mg/L chlorine-containing disinfectant wiped the contaminated area, the Ct values of ORF1ab and N genes and IC genes of internal standard fragment in the amplified target area in 2019-nCoV were all 0, and the Ct values of all genes in the contaminated area in groups 3, 4 and 5 h after UV irradiation were all 0, which completely cleared the pollution and had a strong effect. The effect of PCR Cleaner was second, and 750 mL/L ethanol was the worst. Conclusion: 2 000 mg/L and 5 500 mg/L chlorine-containing disinfectant and ultraviolet irradiation for 3 hours have the best effect of eliminating nucleic acid pollution, which is worth popularizing under appropriate conditions.

Semi-Supervised Screening of COVID-19 from Positive and Unlabeled Data with Constraint Non-Negative Risk Estimator

With the COVID-19 pandemic bringing about a severe global crisis, our health systems are under tremendous pressure. Automated screening plays a critical role in the fight against this pandemic, and much of the previous work has been very successful in designing effective screening models. However, they would lose effectiveness under the semi-supervised learning environment with only positive and unlabeled (PU) data, which is easy to collect clinically. In this paper, we report our attempt towards achieving semi-supervised screening of COVID-19 from PU data. We propose a new PU learning method called Constraint Non-Negative Positive Unlabeled Learning (cnPU). It suggests the constraint non-negative risk estimator, which is more robust against overfitting than previous PU learning methods when giving limited positive data. It also embodies a new and efficient optimization algorithm that can make the model learn well on positive data and avoid overfitting on unlabeled data. To the best of our knowledge, this is the first work that realizes PU learning of COVID-19. A series of empirical studies show that our algorithm remarkably outperforms state of the art in real datasets of two medical imaging modalities, including X-ray and computed tomography. These advantages endow our algorithm as a robust and useful computer-assisted tool in the semi-supervised screening of COVID-19. © 2021, Springer Nature Switzerland AG.

A Novel Aircraft Refueling Behavior Detection Model based on Deep Learning

How to efficiently and accurately monitor the sparse aircraft Refueling behaviors from a large amount of video streams is of great significant for improving the level of management and refueling efficiency of aviation fuel stations. Due to the COVID-19 virus epidemic, the number of flights has dropped severely, the collection of image samples for refueling behaviors from large airport becomes difficult, which hinders the real-time detection of Refueling behaviors and reduces the efficiency of aviation fuel station. Therefore, automatically detecting the refueling behaviors of each station in time and accurately from a large number of aviation refuel stations still keeps challenging. To address this challenge, we propose a novel aircraft refueling behavior detection model based on deep learning, to quickly and accurately determine the refueling behaviors through analysing the video stream collected from the massive cameras deployed in the airport. Our proposed model adopts Inception v3 architecture of ImageNet to realize the model capability of transfer learning, the data augmentation to address the issue of overfitting, and the mAP (mean Average Precision) to test the performance. Our proposed model is also applied in the detection of refueling behaviors in China National Aviation Fuel Group, LTD (CNAF). The practical application results show better performance than other existing methods. Our work will promote the updating of related industry standard. © Published under licence by IOP Publishing Ltd.

Emergency management in fever clinic during the outbreak of COVID-19: an experience from Zhuhai.

Coronavirus disease 2019 (COVID-19) is a global health threat. A hospital in Zhuhai adopted several measures in Fever Clinic Management (FCM) to respond to the outbreak of COVID-19. FCM has been proved to be effective in preventing nosocomial cross infection. Faced with the emergency, the hospital undertook creative operational steps in relation to the control and spread of COVID-19, with special focuses on physical and administrative layout of buildings, staff training and preventative procedures. The first operational step was to set up triaging stations at all entrances and then complete a standard and qualified fever clinic, which was isolated from the other buildings within our hospital complex. Secondly, the hospital established its human resource reservation for emergency response and the allocation of human resources to ensure strict and standardised training methods through the hospital for all medical staff and ancillary employees. Thirdly, the hospital divided the fever clinic into partitioned areas and adapted a three-level triaging system. The experiences shared in this paper would be of practical help for the facilities that are encountering or will encounter the challenges of COVID-19, i.e. to prevent nosocomial cross infection among patients and physicians.

Clinical characteristics and immune function analysis of COVID-19

Objective: To investigate the clinical characteristics in relation to the immune classification in patients with Coronavirus Disease 2019 (COVID-19). Methods: We retrospectively studied the clinical data, cellular and humoral immune function tests results of 101 cases of COVID-19 confirmed by our hospital. The patients were classified according to the Chinese guideline for COVID-19 diagnosis and treatment and divided into two groups as non-severe group and severe group, and the results of cellular and humoral immune function tests were compared. Results: The patients in the severe group were older on average, and the proportion of patients with underlying disease was higher. The counts of CD3, CD4, CD8, CD19, and CD16+CD56 T cells were significantly less in the severe group than in the non-severe group (P0.05). Levels of IgG, IgM, IgA, IgE, complement C3, and complement C4 were determined by mmunoassay, and no difference was found between the two groups. The diagnostic value of the cellular immune cells counts was analyzed by ROC curve. The area under the curve (AUC) of CD3, CD4, CD8, CD19, and CD16+CD56 T cells was 0.987 3, 0.969 3, 0.965 8, 0.817 4, and 0.658 7, respectively (P0.05), and the cut-off values for CD3, CD4, CD8, CD19, and CD16+CD56 T cells were 575.5, 390.0, 214.5, 111.0, and 127.5 cells/μL. Conclusion: Elderly COVID-19 patients with basic diseases are more likely to develop into severe patients. The depletion of each immune cells are more obvious in severe patients. Cellular immune function is helpful to determine the condition of COVID-19 pneumonia patients. © 2020, Editorial Board of Medical Journal of Wuhan University. All right reserved.

[Clinical feature changes of a COVID-19 patient from mild to critical condition and cardiopulmonary pathological results].

Objective: To analyse the clinical history, laboratory tests and pathological data of a patient who suffered from novel coronavirus pneumonia(COVID-19) and provide reference for the clinical treatment of similar cases. Methods: Data of clinical manifestation, laboratory examination, bronchoscopy, echocardiography and cardiopulmonary pathological results were retrospectively reviewed in a case of COVID-19 with rapid exacerbation from mild to critical condition. Results: This patient hospitalized at day 9 post 2019 novel coronavirus(2019-nCoV) infection, experienced progressive deterioration from mild to severe at day 12, severe to critical at day 18 and underwent extracorporeal membrane oxygenation(ECMO) and continuous renal replacement therapy(CRRT) as well as heart lung transplantation during day 28-45 post infection, and died at the second day post heart and lung transplantation. The patient had suffered from hypertension for 8 years. At the early stage of the disease, his symptoms were mild and the inflammatory indices increased and the lymphocyte count decreased continuously. The patient's condition exacerbated rapidly with multi-organ infections, and eventually developed pulmonary hemorrhage and consolidation, pulmonary hypertension, right heart failure, malignant ventricular arrhythmias, liver dysfunction, etc. His clinical manifestations could not be improved despite viral RNAs test results became negative. The patient underwent lung and heart transplantation and finally died of multi organ failure at the second day post lung and heart transplantation. Pathological examination indicated massive mucus, dark red secretions and blood clots in bronchus. The pathological changes were mainly diffused pulmonary hemorrhagic injuries and necrosis, fibrosis, small vessel disease with cardiac edema and lymphocyte infiltration. Conclusions: The clinical course of severe COVID-19 can exacerbate rapidly from mild to critical with lung, liver and heart injuries.