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In this demo, we introduce a web-based misinformation detection system PANACEA on COVID-19 related claims, which has two modules, fact-checking and rumour detection. Our fact-checking module, which is supported by novel natural language inference methods with a self-attention network, outperforms state-of-the-art approaches. It is also able to give automated veracity assessment and ranked supporting evidence with the stance towards the claim to be checked. In addition, PANACEA adapts the bi-directional graph convolutional networks model, which is able to detect rumours based on comment networks of related tweets, instead of relying on the knowledge base. This rumour detection module assists by warning the users in the early stages when a knowledge base may not be available. © 2023 Association for Computational Linguistics.
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9870 thousand people develop tuberculosis (TB) in 2020. Despite being a preventable as well as curable communicable disease, tuberculosis still is the leading communicable disease killer globally. The WHO's End TB Strategy envisions a world free of TB, zero deaths, disease, and suffering due to tuberculosis by 2035. China ranks second for TB cases globally. Over the past 20 years, China has made remarkable achievements in tuberculosis control, with the prevalence and mortality rate of tuberculosis reduced by half compared with 1990. China has achieved the United Nations Millennium Development Goals on tuberculosis control 5 years ahead of schedule. However, in spite of concerted international, regional, and national efforts to address tuberculosis in China, the tuberculosis burden in China is still high. At the same time, China also faces problems such as the high burden of latent TB infection, rifampicin-resistant/ multidrug-resistant tuberculosis, and low detection rate of tuberculosis. China needs to further improve the quality of tuberculosis control work to reduce the incidence of tuberculosis and ultimately achieve the goal of ending tuberculosis. © People's Medical Publishing House, PR of China 2022.
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The spread of COVID-19 has increased the risk of contact transmission between people, and imposes challenges and opportunities for the prevention and control of important parasitic diseases. There may be risks of COVID-19 infection during the implementation of the virus control, including in field investigation and intervention, contacting with fecal samples, or with asymptomatic infected people. Therefore, corresponding prevention and control measures should be taken before and during field investigation, and in sample transportation and detection to prevent the risks effectively. In this paper, the risks and corresponding countermeasures in the above processes are discussed in detail, and the opportunities that COVID-19 brought to the disease control system are also analyzed.Copyright © 2021, National Institute of Parasitic Diseases. All rights reserved.
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The emergence of the Covid-19 pandemic has drawn great attention to vulnerable people affected by major diseases. Among them, Alzheimer's disease (AD) is the most prevalent disease. However, a long-standing challenge is to achieve early diagnosis of AD by detecting biomarkers such as amyloid beta (Aβ42), thus avoiding the labor of specialized hospital personnel and the high cost of imaging examinations using positron emission tomography. In this paper, we report a straightforward approach to realize a non-invasive lab-around fiber (LaF) optical sensor for AD biomarker detection, which is based on a tilted fiber Bragg grating (TFBG) combined with a nanoscale metallic thin film. We successfully demonstrated the detection of Aβ42 in complex biological matrices with a detection limit of 5 pg/mL. Therefore, our TFBG-SPR biosensor platform enables large-scale early disease screening and has great potential for clinical applications in early AD diagnosis. © 2022 IEEE.
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The COVID-19 pandemic has radically transformed the work-from-home (WFH) paradigm, and expanded an organization's cyber-vulnerability space. We propose a novel strategic method to quantify the degree of sub-optimal cybersecurity in an organization of employees, all of whom work in heterogeneous WFH 'siloes'. Specifically, we model the per-unit cost of asymmetric WFH employees to invest in security-improving effort units as time-discounted exponential martingales over time, and derive as benchmark - the centrally-planned socially optimal aggregate employee effort at any given time instant. We then derive the time-varying strategic Nash equilibrium amount of aggregate employee effort in cybersecurity in a distributed setting. The time-varying ratio of these centralized and distributed estimates quantifies the free riding dynamics, i.e., security sub-optimality, within an organization. Rigorous estimates of the degree of sub-optimal cybersecurity will drive organizational policy makers to design appropriate (customized) solutions that voluntarily incentivize WFH employees to invest in required cybersecurity best practices. © 2022 IEEE.
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The lockdowns from the coronavirus disease of 2019 (COVID-19) have led to a reduction in anthropogenic activities and have hence reduced primary air pollutant emissions, which were reported to have helped air quality improvements. However, air quality expressed by the air quality index (AQI) did not improve in Shanghai, China, during the COVID-19 outbreak in the spring of 2022. To better understand the reason, we investigated the variations of nitrogen dioxide (NO2), ozone (O3), PM2.5 (particular matter with an aerodynamic diameter of less than 2.5 μm), and PM10 (particular matter with an aerodynamic diameter of less than 10 μm) by using in situ and satellite measurements from 1 March to 31 June 2022 (pre-, full-, partial-, and post-lockdown periods). The results show that the benefit of the significantly decreased ground-level PM2.5, PM10, and NO2 was offset by amplified O3 pollution, therefore leading to the increased AQI. According to the backward trajectory analyses and multiple linear regression (MLR) model, the anthropogenic emissions dominated the observed changes in air pollutants during the full-lockdown period relative to previous years (2019–2021), whereas the long-range transport and local meteorological parameters (temperature, air pressure, wind speed, relative humidity, and precipitation) influenced little. We further identified the chemical mechanism that caused the increase in O3 concentration. The amplified O3 pollution during the full-lockdown period was caused by the reduction in anthropogenic nitrogen oxides (NOx) under a VOC-limited regime and high background O3 concentrations owing to seasonal variations. In addition, we found that in the downtown area, ground-level PM2.5, PM10, and NO2 more sensitively responded to the changes in lockdown measures than they did in the suburbs. These findings provide new insights into the impact of emission control restrictions on air quality and have implications for air pollution control in the future. © 2023 by the authors.
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In response to the COVID-19 epidemic, online live teaching becomes the main teaching method rather than a choice. Considering the immediate habit change in education, this study aims to identify the critical factors influencing students' engagement and satisfaction with the online live courses using a structural equation model and an online questionnaire survey. Through a comprehensive literature review, four critical factors influencing students' engagement and satisfaction which are instructor behaviors, student characteristics, course organization, the state of health, wellbeing, and sense of community-related (HWC) issues were identified and their relationships as well as measurement indicators for each factor were proposed. Through a survey, 306 valid responses were collected from civil engineering students in China in 2020. The results showed that instructor behaviors and student characteristics have the highest impact on student engagement and perceived learning, respectively. Moreover, the mediating effects of student engagement between instructor behaviors and student characteristics and perceived learning and satisfaction are statistically significant. Furthermore, the state of HWC issues caused by intensive online learning does have a significant negative impact on student satisfaction. Besides, the relative importance of practices affecting student online learning effects was prioritized. The findings contribute to the body of knowledge of online teaching theories and strategies. Moreover, the instructor and the education manager can improve their online live arrangement by referencing the findings of this study. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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Objective To investigate the nutritional status and associated factors of vitamin D among children aged 0 to 12 years old in Chongqing. Methods From January 2019 to December 2021 1 877 children aged 0-6 years who received regular child health care were randomly selected from Chongqing maternal and child health hospital and 707 school-age children were also selected from three primary school in Chongqing for investigation. The serum sample were collected for detecting serum 25- OH -D level by chemiluminescence method and the possible influencing factors of vitamin D deficiency VDD were analyzed. Results The average serum 25- OH -D concentration of children was 39.9±9.1 ng/mL with the positive rate of VDD was 14.59%. There were significant differences of VDD positive rate in different age visiting time visiting season body shape outdoor activity time and vitamin D supplementation 0-3 years old vs 4-6 years old vs 7-12 years old 14.73% vs 22.19% vs 10.47% visiting season spring vs summer vs autumn vs winter 12.97% vs 10.65% vs 14.86% vs 21.33% pre COVID-19 epidemic vs post COVID-19 epidemic 11.18% vs 17.08% underweight or normal vs overweight or obesity 12.34% vs 26.13% adequate outdoor activity time vs inadequate 11.84% vs 16.27% regular vitamin D supplementation vs irregular vitamin D supplementation 11.71% vs 15.62% χ2 = 26.17 17.59 30.98 53.74 9.60 6.17 P<0.05. Underweight or normal body weight sufficient outdoor activities and regular vitamin D supplementation were associated with less vitamin D deficiency with OR OR95%CI at 0.68 0.55-0.84 0.57 0.25-0.77 and 0.62 0.44-0.85 P<0.05. Conclusion The prevalence of VDD among preschool and school-age children is high in Chongqing. Integrated prevention and control strategies incluing overweight or obesity control increasing outdoor activities and oral vitamin D supplements should be taken. © 2022 Authors. All rights reserved.
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Background:Many issues, such as severity assessment and antibody responses, remain to be answered eagerly for evaluation and understanding of COVID-19. Immune lesion is one of key pathogenesis of the disease. It would be helpful to understand the disease if an investigation on antigenemia and association was conducted in the patients with SARS-CoV-2 infection.Methods:A total of 156 patients admitted to the First People's Hospital of Hefei or Anhui Provincial Hospital on January to February 2020 were involved in this study. SARS-CoV-2 nucleocapsid (NP) antigen, specific IgM/IgG antibodies, and RNA were detected in sequential sera from three COVID-19 patients, and additional 153 COVID-19 patients by means of NP-antigen capture enzyme-linked immunosorbent assay, colloidal gold quick diagnosis, and real-time RT-PCR, respectively. The clinical types of COVID-19 patients were classified into asymptomatic, mild, moderate, severe, and critical, following on the Chinese guideline of COVID-19 diagnosis and treatment. The demographic and clinical data of patients were obtained for comparable analysis.Results:NP antigen was detected in 5 of 20 sequential sera collected from three COVID-19 patients with typically clinical symptoms, and 60.13% (92/153) expanded samples collected within 17 days after illness onset. No SARS-CoV-2 RNA segment was detected in these sera. The NP positive proportion reached a peak (84.85%, 28/33) on 6 to 8 days after illness onset. Both NP concentration and positive proportion were increased with the increase of clinical severity of COVID-19. Compared to NP negative patients, NP positive patients had older age [years, medians (interquartile ranges (IQR)), 49 (6) vs. 31 (11)], lower positive proportion of NP specific IgM [27.17% (25/92) vs. 59.02% (36/61)], and IgG [21.74% (20/92) vs. 59.02% (36/61)] antibodies, and longer duration [days, medians (IQR), 24 (10) vs. 21 (13)] from illness to recovery.Conclusions:SARS-CoV-2 NP antigenemia occurred in COVID-19, and presented highly prevalent at early stage of the disease. The antigenemia was related to clinical severity of the disease, and may be responsible for the delay of detectable SARS-Cov-2 IgM. © 2022 Journal of Bone and Joint Surgery Inc.. All rights reserved.
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Background:Coronavirus disease 2019 (COVID-19) is a serious and even lethal respiratory illness. The mortality of critically ill patients with COVID-19, especially short term mortality, is considerable. It is crucial and urgent to develop risk models that can predict the mortality risks of patients with COVID-19 at an early stage, which is helpful to guide clinicians in making appropriate decisions and optimizing the allocation of hospital resoureces.Methods:In this retrospective observational study, we enrolled 949 adult patients with laboratory-confirmed COVID-19 admitted to Tongji Hospital in Wuhan between January 28 and February 12, 2020. Demographic, clinical and laboratory data were collected and analyzed. A multivariable Cox proportional hazard regression analysis was performed to calculate hazard ratios and 95% confidence interval for assessing the risk factors for 30-day mortality.Results:The 30-day mortality was 11.8% (112 of 949 patients). Forty-nine point nine percent (474) patients had one or more comorbidities, with hypertension being the most common (359 [37.8%] patients), followed by diabetes (169 [17.8%] patients) and coronary heart disease (89 [9.4%] patients). Age above 50 years, respiratory rate above 30 beats per minute, white blood cell count of more than10 × 109/L, neutrophil count of more than 7 × 109/L, lymphocyte count of less than 0.8 × 109/L, platelet count of less than 100 × 109/L, lactate dehydrogenase of more than 400 U/L and high-sensitivity C-reactive protein of more than 50 mg/L were independent risk factors associated with 30-day mortality in patients with COVID-19. A predictive CAPRL score was proposed integrating independent risk factors. The 30-day mortality were 0% (0 of 156), 1.8% (8 of 434), 12.9% (26 of 201), 43.0% (55 of 128), and 76.7% (23 of 30) for patients with 0, 1, 2, 3, ≥4 points, respectively.Conclusions:We designed an easy-to-use clinically predictive tool for assessing 30-day mortality risk of COVID-19. It can accurately stratify hospitalized patients with COVID-19 into relevant risk categories and could provide guidance to make further clinical decisions. © 2021 The Chinese Medical Association, Published by Wolters Kluwer Health, Inc.
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The COVID-19 pandemic forced a dramatic change from face-to-face learning environments to intensive learning environments. This study aimed to identify and quantify the determinants of student learning effects and their conduction mechanism in intensive online environments. Using a structural equation model and a questionnaire survey, this study proposed and validated the relationships among six constructs including student engagement, perceived learning, satisfaction, instructor behaviours, student characteristics, and the state of health, well-being, and sense of community-related (HWC) issues. 306 valid responses from civil engineering students in 19 universities in China were used to validate the proposed relationships. The measurement and structural model evaluation indicated that the model fit of the fitted model is acceptable with x(2)/df = 2.548, RMSEA = 0.071, AGFI =0.78, and CFI = 0.93. The results first showed the key factors for student learning effects from the instructor, the student, and the HWC issues with a factor loading greater than 0.8. This study further inferred from the different path coefficients in the fitted model and the mediating model that instructor behaviours greatly influence student perceived learning and satisfaction through student engagement with a contribution of 100% and 58%, respectively;student characteristics have a decisive impact on student perceived learning with a path coefficient of 0.59;HWC issues negatively impact student satisfaction with a path coefficient of -0.11. The findings enrich online education theories in an intensive online environment by clarifying and quantifying the influencing mechanism of the determinants. The findings also advance education practices for students, instructors, and educational administrators by helping them find out their contribution to learning effectiveness and the key factors to improve future online teaching levels.
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The rules on force majeure in Chinese law as applied to port terminal opera-tions are vague, and the application of these rules can be inconsistent, at the discretion of the judges. The resulting uncertainty causes difficulties for those involved in port terminal operations in predicting their liabilities. This article attempts to conduct two case studies about force majeure in the context of port terminal operations, first concerning natural disasters and, second, concerning the COVID-19 pandemic. The article concludes by suggesting that the stand-ards for identifying force majeure and the rules for applying force majeure are in need of clarification. It is argued that, in cases where force majeure does not frustrate the purposes of the contract, the legal consequences may be better decided by referring to the principle of fairness and to the rules of change of circumstances.
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Between August and September, 2021, this study included 605 SARS-CoV-2 natural infection cases and 589 SARS-CoV-2 breakthrough cases from Nanjing and Yangzhou, as well as 690 inactivated COVID-19 vaccine recipients from Changzhou, China. In SARS-CoV-2 natural infection cases, the age range was 19-91 years (median age: 66 year), and the medians(Q1,Q3) of IgG titers were 0.19 (0.06-1.31), 3.70 (0.76-69.48), 15.31 (2.59-82.16), 4.41 (0.99-31.74), 2.31 (0.75-13.83), 2.28 (0.68-9.94) and 2.80 (1.00-9.53) at one to seven weeks after SARS-CoV-2 infection, respectively. In SARS-CoV-2 breakthrough cases, the age range was 18-76 years (median age: 45 year), and the medians(Q1,Q3)of IgG titers were 1.93 (0.34-26.67), 38.87 (7.90-121.0), 75.09 (11.85-123.70), 21.97 (5.20-95.58), 13.97 (3.47-46.82), 9.56 (2.48-33.38) and 4.38 (1.87-11.00) at one to seven weeks after SARS-CoV-2 infection, respectively. In inactivated COVID-19 vaccine recipients, the age range was 18-87 years (median age: 47 years), and the medians(Q1,Q3)of IgG titers were 16.22 (15.84-33.42), 5.35 (2.96-13.23), 3.30 (2.18-6.18), 3.14 (1.16-5.70), 2.77 (1.50-4.52), 2.72 (1.76-4.36), 2.01 (1.27-3.51) and 1.94 (1.35-3.09) at one to eight months after SARS-CoV-2 infection, respectively. The results suggested that IgG antibodies increased gradually within two weeks after SARS-CoV-2 infection, then declined gradually at three to seven weeks in SARS-CoV-2 natural infection cases. In SARS-CoV-2 breakthrough cases, IgG antibodies increased rapidly within two weeks, then declined gradually at three to seven weeks after SARS-CoV-2 infection. Additionally, IgG antibodies decreased rapidly within three months, then decreased gradually and remained at a low level within three months after immunization.
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COVID-19 Vaccines , COVID-19 , Humans , Aged , Middle Aged , Young Adult , Adult , Aged, 80 and over , Adolescent , SARS-CoV-2 , Kinetics , Antibodies, Viral , Immunoglobulin GABSTRACT
Objective: To investigate the distribution characteristics of respiratory non-bacterial pathogens in children in Ningbo from 2019 to 2021. Methods: A retrospective analysis was performed on 23 733 children with respiratory tract infection who visited the department of pediatrics of Ningbo Women and Children's Hospital from July 2019 to December 2021. There were 13 509 males (56.92%) and 10 224 females (43.08%), with an age range of 1 day to 18 years old. There were 981 cases in the neonatal group (younger than 1 month old), 5 880 cases in the infant group (1 month to younger than 1 year old), 6 552 cases in the toddler group (1 to younger than 3 years old), 7 638 cases in the preschool group (3 to younger than 7 years old), and 2 682 cases in the school-age group (7 to 18 years old). Thirteen respiratory pathogens were detected by multiple polymerase chain reaction (PCR) based on capillary electrophoresis, and SPSS 23.0 software was used for statistical analysis of the results, the count data were expressed as percentages, and the χ2 test was used for comparison between groups. Results: Of the 23 733 specimens, 13 330 were positive for respiratory pathogens, with a total positive rate of 56.17%. The positive rates of human rhinovirus (HRV) 24.05% (5 707/23 733), human respiratory syncytial virus (HRSV) 10.45% (2 480/2 3733) and mycoplasma pneumoniae (Mp) 7.03% (1 668/23 733) were in the first three. The positive rates of pathogens in the male and female children were 57.47% (7 763/13 509) and 54.45% (5 567/10 224), respectively, and the difference was statistically significant (χ2=21.488, P<0.001). The positive rates in the neonatal group, infant group, toddler group, preschool group, and school-age group were 31.80% (312/981), 54.71% (3 217/5 880), 63.23% (4 143/6 552), 59.83% (4 570/7 638), 40.57% (1 088/2 682), respectively, and the difference among the groups was statistically significant (χ2=681.225, P<0.001). The single infection rate was 47.43% (11 256/23 733), the mixed infection rate of two or more pathogens was 8.74% (2 074/23 733), most of which were mixed infections of two pathogens. HRV, HADV, HCOV, Ch disseminated in the whole year. HRSV, HMPV, Boca, HPIV occurred mostly in fall and winter. The positive rates of FluA, FluB, Mp were at a low level after the corona virus disease 2019 (COVID-19) epidemic (2020 and 2021). The positive rates of FluA, H1N1, H3N2, FluB, HADV, Mp in 2020 were significantly lower than in 2019 (P<0.05). The positive rates of HPIV, HRV, HCOV, Ch in 2020 were significantly higher than in 2019 (P<0.05). The positive rates of FluA, H1N1, H3N2, HPIV, HCOV, Mp, Ch in 2021 were significantly lower than in 2020 (P<0.05). The positive rates of Boca, HMPV, HRSV in 2021 were significantly higher than in 2020 (P<0.05). Conclusion: From 2019 to 2021, the main non-bacterial respiratory pathogens of children in Ningbo City were Mp and HRV, and the detection rates of respiratory pathogens varied among different ages, seasons and genders.
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COVID-19 , Coinfection , Influenza A Virus, H1N1 Subtype , Respiratory Syncytial Virus, Human , Respiratory Tract Infections , Infant , Infant, Newborn , Child , Child, Preschool , Humans , Male , Female , Adolescent , Influenza A Virus, H3N2 Subtype , Retrospective Studies , Respiratory Tract Infections/epidemiology , Mycoplasma pneumoniaeABSTRACT
OBJECTIVES: The COVID-19 pandemic has significantly affected healthcare systems and daily well-being. However, the reports of the indirect impacts of the pandemic on preterm birth remain conflicting. We performed a meta-analysis to examine whether the pandemic altered the risk of preterm birth. STUDY DESIGN: This was a systematic review and meta-analysis of the previous literature. METHODS: We searched MEDLINE and Embase databases until March 2022 using appropriate keywords and extracted 63 eligible studies that compared preterm between the COVID-19 pandemic period and the prepandemic period. A random effects model was used to obtain the pooled odds of each outcome. The study protocol was registered with PROSPERO (No. CRD42022326717). RESULTS: The search identified 3827 studies, of which 63 reports were included. A total of 3,220,370 pregnancies during the COVID-19 pandemic period and 6,122,615 pregnancies during the prepandemic period were studied. Compared with the prepandemic period, we identified a significant decreased odds of preterm birth (PTB; <37 weeks' gestation; pooled odds ratio [OR; 95% confidence interval (CI)] = 0.96 [0.94, 0.98]; I2 = 78.7%; 62 studies) and extremely PTB (<28 weeks' gestation; pooled OR [95% CI] = 0.92 [0.87, 0.97]; I2 = 26.4%; 25 studies) during the pandemic, whereas there was only a borderline significant reduction in the odds of very PTB (<32 weeks' gestation; pooled OR [95% CI] = 0.93 [0.86, 1.01]; I2 = 90.1%; 33 studies) between the two periods. There was significant publication bias for PTB. CONCLUSION: Pooled results suggested the COVID-19 pandemic was associated with preterm birth, although there was only a borderline significant reduction for very PTB during the pandemic compared with the prepandemic period. Large studies showed conflicting results, and further research on whether the change is related to pandemic mitigation measures was warranted.
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Amid rising industrialization and economic progress, China has shown exponential growth in energy and fossil fuel consumption;therefore, it faces great global concern and widespread criticism for energy and fuel conservation to reduce fuel-related emissions. In addition, the recent spread of COVID-19 instigates the impact of environmental pollution, exaggerates the virus intensity, and lowers people's immunity due to poor air quality. Therefore, this study explored the role of green energy efficiency and climate technologies in achieving carbon neutrality in China using an advanced quantile autoregressive distributed lag (QARDL) framework. The results indicated that green energy efficiency and climate technologies significantly reduce environmental pollution across all quantiles in the long run. In contrast, urbanization enhances environmental degradation at lower and higher emissions quantiles, while trade only promotes environmental pollution at lower quantiles. These findings suggested using alternative energy sources and carbon-reducing technologies to ensure a sustainable environment.
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A stamp-based printing technique was applied to transfer the β-Ga<sub>2</sub>O<sub>3</sub> films grown by pulsed laser deposition (PLD) from Si substrates onto some flexible substrates, such as PET, PEN, and PI. It is demonstrated that the β-Ga<sub>2</sub>O<sub>3</sub>-based flexible solar-blind photodetectors (SBPDs) exhibit brilliant optoelectrical performances with a low dark current of 1.7 pA at 10 V, a I<sub>254nm</sub>/I<sub>dark</sub> ratio of 1.2×103, rise (τ<sub>r1</sub> = 0.079 s and τ<sub>r2</sub> = 0.413 s) and decay (τ<sub>d1</sub> = 0.029 s and τ<sub>d2</sub> = 0.316 s) times. In a further step, flexible imaging sensor arrays based on the β-Ga<sub>2</sub>O<sub>3</sub>/PET were fabricated, which exhibit good imaging capability and resolution. Moreover, wearable UVC-alarms based on the β-Ga<sub>2</sub>O<sub>3</sub>/PET were realized to monitor the UVC radiation in the environment in real time, which can be used in the COVID-19-related area. IEEE
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Purpose: With the rapid development of sharing economy, travelers are facing choices between conventional hotels and the peer-to-peer sharing accommodation in urban tourism. The purpose of this study is to examine how travelers form their preferences in such choice situations and whether/how their preference formation mode would change with the COVID-19 pandemic. Design/methodology/approach: A relative preference model was constructed and estimated for both domestic and outbound tourists, based on two waves of survey data collected before and after the COVID-19. The results of this study were compared to derive the evolution of preference formation patterns. Findings: A set of 15 key value attributes and personal traits was identified, together with their differential effects with the pandemic. Their divergent effects between domestic and outbound trips were also delineated. Based on these findings, the competitive edges and advantageous market profiles were depicted for both hotel and sharing accommodation sectors. Originality/value: This study contributes to the knowledge of tourists’ preference between accommodation types and adds empirical evidences to the impact of the pandemic on tourist behavior patterns. Both hotel and sharing accommodation practitioners can benefit from the findings to enhance their competitiveness. © 2022, Emerald Publishing Limited.
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In this work, we coated perovskite quantum dots (CsPbBr3) with metal oxide (ZnO) by an in-situ oxidation strategy to obtain CsPbBr3@ZnO nanocrystals, which effectively improved the moisture stability of the perovskite material. In addition, the ZnO layer can also transfer the interaction with gas molecules to the inner CsPbBr3, giving the CsPbBr3@ZnO nanocrystals good gas-sensing properties at room temperature. This study considered CsPbBr3@ZnO films’ structural, morphological, and gas sensing properties;and simulated breath monitoring tests. Later a sensor based on CsPbBr3@ZnO nanocrystals was prepared and used to detect the presence of heptanal (a breath biomarker for lung cancer and COVID-19) in different gases, including air, artificial breath, and real breath. The sensor displayed a fairish sensitivity (S = 0.36) alongside a brief response/recovery time (36.5 s/5.3 s) towards 200 ppm heptanal prepared with air, and the limit of detection could reach up to 2 ppm in the air and 3 ppm in artificial breath (made up of air, ethanol, isopropanol, 7-tridecanone, and n-tetradecane). Furthermore, the intelligent classification algorithms were used to identified the real breath samples containing heptanal (1–5 ppm) with an 82.5% accuracy rate in simulated breath monitoring tests. Theory calculation results showed that the good response to heptanal was attributed to both the positive adsorption energy (+3 eV) and the increased lattice distortion induced by heptanal. These sensors show great potential to be an effective method for early detection and treatment of lung cancer and COVID-19 for a healthy and prolonged life. We believe that this research will open the door toward more stable and practical perovskite-based sensors.
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The pandemic of COVID-19 has led to a surge increase in the production of masks. Due to the rapid propagation of COVID-19 and the long survival time of plastic surfaces, a large number of masks are discharged into the environment without treatment. In this paper, the release of microplastics (MPs) in nature was simulated by using mask samples irradiated by ultraviolet (UV) light. After 28 days of ultraviolet radiation, part of the main chain of the mask was broken and a large number of transparent MPs fell off. The longer the UV irradiation time, the larger the proportion of small particle MPs. The middle layer of surgical mask is the most difficult to release MPs due to charge treatment, and N95 mask is the most difficult to degrade the inner material. © 2022, HARD Publishing Company. All rights reserved.