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1.
Complexity ; 2022, 2022.
Article in English | ProQuest Central | ID: covidwho-1642946

ABSTRACT

The isolation requirements of the coronavirus epidemic and the intuitive display advantages of live-streaming have led to an increasing number of retailers shifting to social live-streaming platforms and e-commerce live-streaming platforms to promote and sell their products in real time. However, the provision of live-streaming services will also incur high live-streaming effort costs. In this paper, we develop two decision models for retailers to sell goods through a single online shop and both online shop and live-streaming room;we also present the optimal decisions of pricing and live-streaming efforts. Furthermore, we identify the profitability conditions for retailers to determine when to provide live-streaming services. In addition, we examine the impact of the provision of live-streaming services on the optimal price and live-streaming effort. We obtain three findings. First, there is a unique optimal decision on the price and live-streaming effort under certain conditions. Second, when the effect coefficient of the live-streaming room reaches a certain threshold, there are enough customers who enter the live-streaming room to watch and buy and it is profitable for retailers to provide live-streaming service. Finally, the optimal price and live-streaming effort increase with the increase in average return loss, the effect coefficient of live-streaming effort, and the extra return rate and decrease with the increase in the proportion of customers who choose to buy in the online shop and the price discount coefficient in the live-streaming room.

2.
Front Immunol ; 12: 791753, 2021.
Article in English | MEDLINE | ID: covidwho-1639168

ABSTRACT

Background: Infection of SARS-CoV-2 may cause acute respiratory syndrome. It has been reported that SARS-CoV-2 nucleocapsid protein (N-protein) presents early in body fluids during infection. The direct involvement of N-protein in lung injury is poorly understood. Methods: Recombinant N-protein was pretreated with polymyxin B, a lipopolysaccharide (LPS)-neutralizing agent. C57BL/6, C3H/HeJ (resistant to LPS), and C3H/HeN (control for C3H/HeJ) mice were exposed to N-protein via intratracheal administration to examine acute lung injury. In vitro, bone marrow-derived macrophages (BMDMs) were cultured with N-protein to study phosphorylation of nuclear factor kappa B (NF-ĸB) p65, macrophage polarization, and expression of proinflammatory cytokines. Results: N-protein produced acute lung injury in C57BL/6 mice, with elevated protein permeability, total cell count, neutrophil infiltration, and proinflammatory cytokines in the bronchioalveolar lavage. N-protein also induced lung injury in both C3H/HeJ and C3H/HeN mice, indicating that the effect could not be attributed to the LPS contamination. N-protein triggered phosphorylation of NF-ĸB p65 in vitro, which was abolished by both N-protein denaturation and treatment with an antibody for N-protein, demonstrating that the effect is N-protein specific. In addition, N-protein promoted M1 macrophage polarization and the expression of proinflammatory cytokines, which was also blocked by N-protein denaturation and antibody for N-protein. Furthermore, N-protein induced NF-ĸB p65 phosphorylation in the lung, while pyrrolidine dithiocarbamate, an NF-ĸB inhibitor, alleviated the effect of N-protein on acute lung injury. Conclusions: SARS-CoV-2 N-protein itself is toxic and induces acute lung injury in mice. Both N-protein and NF-ĸB pathway may be therapeutic targets for treating multi-organ injuries in Coronavirus disease 2019 (COVID-19).


Subject(s)
Acute Lung Injury/virology , COVID-19 , Coronavirus Nucleocapsid Proteins/toxicity , NF-kappa B/metabolism , Acute Lung Injury/metabolism , Animals , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , Phosphoproteins/toxicity , SARS-CoV-2
3.
Atmospheric Pollution Research ; : 101232, 2021.
Article in English | ScienceDirect | ID: covidwho-1466049

ABSTRACT

The Spring Festival is the most important holiday in China, and human activity and population mobility may contribute greatly to air quality. According to the satellite-based tropospheric nitrogen dioxide (NO2) column and ground-based observational concentration of NO2 in megacities from 2013 to 2018 around the Spring Festival, we found that NO2 concentration obviously decreases, presenting a “tide phenomenon”, particularly in the megacities, with the tropospheric NO2 column density decreasing by 31.8%–44.5%. The tropospheric NO2 column density in Beijing decreased by 41.6% and rebounded by 22.3% after the festival. Vehicle sources were among the important causes of NOx emissions in the megacities, and traffic intensity decreased significantly during the festival. As the coronavirus disease 2019 (COVID-19) pandemic progresses, the traffic intensity in urban areas is decreasing significantly, with the tropospheric NO2 column density decreasing by 56.2% and rebounding by only 6.8% in 2020, without the “tide phenomenon”.

4.
Huan Jing Ke Xue ; 42(9): 4126-4139, 2021 Sep 08.
Article in Chinese | MEDLINE | ID: covidwho-1368044

ABSTRACT

To reduce the risks of COVID-19 on society and the health of the general public, necessary prevention and control measures were implemented throughout China in 2020. Consequently, air quality was greatly improved due to lower emissions. However, the improvement of air quality could also be closely related to meteorological conditions. During quarantine (January 27 to February, 2020), reductions were observed in the concentration of all air pollutants in Henan Province (PM2.5, PM10, SO2, CO, and NO2 decreased by 36.89%, 34.18%, 19.43%, 29.85%, and 58.51%, respectively) relative to measurements taken from January 1 to 26, 2020. The only exception was for the concentration of O3, which increased by 69.64%. This study evaluates the importance of meteorological conditions in air pollution, through simulation with a long-and-short-term memory network (LSTM) and a machine learning algorithm. Results show that meteorological conditions play a crucial role in air pollutant formation. Given favorable meteorological factors, the concentrations of pollutants could be reduced by 15%-30%, while the reduction due to anthropogenic emission control ranges from 6%-40%. During the epidemic, meteorological conditions and human emissions accounted for 34.84% and 34.81% of the increase in O3 concentration, respectively. The results show that primary pollutant concentrations are more sensitive to the intensity of anthropogenic emissions. However, secondary pollutants are more dependent on meteorological factors. Furthermore, a nonlinear relationship has been identified between O3 concentration and to emission intensity. Further investigation into the causes of the rise in O3 concentration is necessary to gain a greater understanding and better control of particulate matter and O3 pollution.


Subject(s)
Air Pollution , COVID-19 , Algorithms , Humans , Machine Learning , Pandemics , SARS-CoV-2
5.
J Affect Disord ; 294: 128-136, 2021 Nov 01.
Article in English | MEDLINE | ID: covidwho-1317696

ABSTRACT

BACKGROUND: We aimed to explore the risk profiles attributable to psychosocial and behavioural problems during the coronavirus disease 2019 pandemic. To this end, we created a risk-prediction nomogram model. METHODS: A national multicentre study was conducted through an online questionnaire involving 12,186 children (6-11 years old) and adolescents (12-16 years old). Respondents' psychosocial and behavioural functioning were assessed using the Achenbach Child Behaviour Checklist (CBCL). Data were analysed using STATA software and R-language. RESULTS: The positive detection rate of psychological problems within Wuhan was greater than that outside Wuhan for schizoid (P = 0.005), and depression (P = 0.030) in children, and for somatic complaints (P = 0.048), immaturity (P = 0.023), and delinquent behaviour (P = 0.046) in adolescents. After graded multivariable adjustment, seven factors associated with psychological problems in children and adolescents outside Wuhan were parent-child conflict (odds ratio (OR): 4.94, 95% confidence interval (95% CI): 4.27-5.72), sleep problems (OR: 4.05, 95% CI: 3.77-4.36), online study time (OR: 0.41, 95% CI: 0.37-0.47), physical activity time (OR: 0.510, 95% CI: 0.44-0.59), number of close friends (OR: 0.51, 95% CI: 0.44-0.6), time spent playing videogames (OR: 2.26, 95% CI: 1.90-2.69) and eating disorders (OR: 2.71, 95% CI: 2.35-3.11) (all P < 0.001). Contrastingly, within Wuhan, only the first four factors, namely, parent-child conflict (5.95, 2.82-12.57), sleep problems (4.47, 3.06-6.54), online study time (0.37, 0.22-0.64), and physical activity time (0.42, 0.22-0.80) were identified (all P < 0.01). Accordingly, nomogram models were created with significant attributes and had decent prediction performance with C-indexes over 80%. LIMITATION: A cross-sectional study and self-reported measures. CONCLUSIONS: Besides the four significant risk factors within and outside Wuhan, the three additional factors outside Wuhan deserve special attention. The prediction nomogram models constructed in this study have important clinical and public health implications for psychosocial and behavioural assessment.


Subject(s)
COVID-19 , Problem Behavior , Adolescent , Child , Cross-Sectional Studies , Humans , Nomograms , Pandemics , Risk Factors , SARS-CoV-2
6.
Transl Psychiatry ; 11(1): 342, 2021 06 03.
Article in English | MEDLINE | ID: covidwho-1258580

ABSTRACT

This study aims to explore the psychosocial and behavioral problems of children and adolescents in the early stage of reopening schools. In this national cross-sectional study, a total of 11072 students from China were naturally divided into two groups based on their schooling status: reopened schools (RS) and home schooling (HS) group. The psychosocial and behavioral functioning were measured by Achenbach Child Behaviour Checklist (CBCL) and compared in these two groups. Multivariable logistic regression analyses were conducted to explore the independent predictors associated with the psychosocial and behavioral problems. Our results showed that the students in the RS group had more adverse behaviors than that of HS group. The RS group had the higher rates of parent-offspring conflict, prolonged homework time, increased sedentary time and sleep problems (all p < 0.001). When separate analyses were conducted in boys and girls, the RS group had the higher scores for (1) overall behavioral problems (p = 0.02 and p = 0.01), internalizing (p = 0.02 and p = 0.02) and externalizing (p = 0.02 and p = 0.004) behaviors in the 6-11 age group; (2) externalizing (p = 0.049 and p = 0.006) behaviors in the 12-16 age group. Multivariable regression showed parent-offspring conflict and increased sedentary time were the most common risk factors, while physical activity and number of close friends were protective factors for behavior problems in RS students (p < 0.01 or 0.05). The present study revealed that students' psychosocial and behavioral problems increased in the early stage of schools reopened unexpectedly. These findings suggest that close attention must be paid and holistic strategies employed in the school reopening process of post-COVID-19 period.


Subject(s)
COVID-19 , Problem Behavior , Adolescent , Child , China/epidemiology , Cross-Sectional Studies , Female , Humans , Male , Pandemics , SARS-CoV-2 , Schools
7.
Environ Pollut ; 285: 117257, 2021 Sep 15.
Article in English | MEDLINE | ID: covidwho-1217544

ABSTRACT

Reusing treated wastewater can effectively alleviate water shortages and water contamination problems but depends on ensuring the safety of the reclaimed water that is produced. The operating and management conditions for water reclamation plants in China have been changed since the outbreak of the COVID-19 epidemic in China at the end of 2019 to prevent emerging viruses being spread through wastewater treatment processes and the reclaimed water that is produced. Removal of pathogens and trace organic compounds (e.g., pharmaceuticals and personal care products and endocrine disrupting chemicals) in a real water reclamation plant after the start of COVID-19 epidemic was studied. Disinfection byproduct formation caused by chlorine being added to meet disinfection requirements was also assessed. The pathogenic microorganism concentrations in effluent were <2 (most probable number)/L, and the removal rates for most trace organic compounds were >80% when advanced treatments were performed using ozone, ultraviolet light, and chlorine doses of 2 mg/L, 20.5 mJ/cm2, and 2-3 mg/L, respectively. The main disinfection byproduct produced at a chlorine dose of 2 mg/L and a residence time of 1 h was chloroform (at concentrations <15 µg/L). The results indicated that the water reclamation processes with modified conditions gave high pathogen and trace organic compound removal rates and reasonably well-controlled disinfection byproduct concentrations.


Subject(s)
COVID-19 , Water Pollutants, Chemical , Water Purification , Chlorine , Disinfection , Humans , SARS-CoV-2 , Waste Water , Water , Water Pollutants, Chemical/analysis
8.
Nano Energy ; 79: 105434, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-813793

ABSTRACT

The COVID-19 pandemic has caused an unprecedented human and health crisis. And the shortage of protective equipment, especially the personal protective disposable surgical masks, has been a great challenge. Here, we developed an effective and simple scheme to prolong the lifetime of disposable surgical masks without changing their current structure, which is beneficial to solve the shortage of personal masks. After electrifying the meltblown PP filter by the new-developed single-electrode-based sliding triboelectric nanogenerator (TENG) charge replenishment (NGCR) technology, the processed filter is bipolar charged and has a filtration efficiency beyond 95% for the particulate matter (PM) ranging from PM0.3 to PM10.0. Further, we demonstrate the 80 °C dry heating is an effective decontamination method. This method is compatible with single-electrode-based sliding TENG charge replenishment technology. The 80 °C dry heating and the NGCR technology can make up an effective regeneration procedure for the mask. Even after ten cycles of simulated 4 h wearing process and such regeneration procedure, the filtration efficiency of the disposable surgical masks PM0.3 is still higher than 95%.

9.
Infect Genet Evol ; 84: 104411, 2020 10.
Article in English | MEDLINE | ID: covidwho-592211

ABSTRACT

Jingmen tick virus (JMTV) is a recently identified virus which provides an unexpected connection between segmented and unsegmented RNA viruses. Recent investigations reveal that JMTV including JMTV-like virus (Alongshan virus) could be associated with human disease, suggesting the significance of JMTV in public health. To better understand the genetic diversity and host range of JMTV, a total of 164 rodents representing 8 species were collected in Qapqal Xibe county of Xinjiang Uygur Autonomous Region, China, and were screened for JMTVs using RT- PCR. Consequently, JMTV was identified in 42 rodents including 23 Microtus arvalis voles (24.5%), 9 Apodemus uralensis mice (29.0%), 5 Mus musculus mice, 1 Rhombomys opimus gerbil, 1 Meriones tamariscinus gerbil, 1 Meriones libycus gerbil, 1 Cricetulus migratorius hamster and 1 Microtus gregalis vole. Interestingly, nearly complete genome sequences were successfully recovered from 7 JMTV positive samples. Although the newly identified rodent JMTVs were closely related to those previously identified in ticks from China, based on the phylogenetic analysis of the S1, S2 and S3 segments, the newly identified rodent viruses clustered into two genetic groups. One group comprised of viruses only found in M. arvalis, while another group included viruses from A. uralensis, C. migratorius and M. gregalis. However, all rodent viruses clustered together in the S4 tree. Considering rodents live in close proximity to humans, more efforts are needed to investigate the role of rodents in the evolution and transmission of JMTV in nature.


Subject(s)
Flaviviridae/genetics , Flaviviridae/isolation & purification , Rodentia/virology , Animals , Flaviviridae/classification , Phylogeny
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