ABSTRACT
The demand for face masks is increasing exponentially due to the coronavirus pandemic and the particulate matter (PM) in the atmosphere. As a result, an enormous number of disposable mask filters have been produced and discarded, contributing to plastic waste. Underprivileged people who cannot afford to purchase commercial face masks have started making fabric masks with waste clothing;however, this material does not effectively filter viruses or PM. Therefore, in this study, a chitosan coating was applied to clothing fabrics to increase their effectiveness as face masks. The improvement in the PM removal efficiency owing to the chitosan polymer was observed for stocking, innerwear, and bamboo materials, but not for cotton. Furthermore, chitosan prepared in the form of a nanowhisker (CsW) achieved a PM 2.5 removal efficiency of 96% in a five-layer cotton fabric. In addition, a commercial biodegradable poly(lactic acid) filter was coated with CsW, which increased the PM 2.5 removal efficiency from 67% to 83%. Additionally, microbial growth was significantly suppressed in the chitosan-coated fabrics, and the degree to which it was suppressed depended on the coating concentration. The study will aid in the utilization of face mask filters that are more sustainable, efficient, and widely accessible. © 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.
ABSTRACT
OBJECTIVE: To perform a systematic review of case reports or case series regarding thrombosis with thrombocytopenia syndrome (TTS) and cerebral venous thrombosis (CVT) related to ChAdOx1 nCoV-19 vaccination to address the clinical features, laboratory findings, treatment modalities, and prognosis related with CVT. SUBJECTS AND METHODS: We included 64 TTS patients from 19 articles, 6 case series and 13 case reports, in which thrombosis occurred after the first dose of ChAdOx1 nCoV-19 vaccination published up to 30 June 2021 in Embase, ePubs, Medline/PubMed, Scopus, and Web of Science databases. RESULTS: Of the 64 TTS patients, 38 (59.3%) had CVT. Patients with CVT were younger (median 36.5 vs. 52.5 years, p<0.001), had lower fibrinogen levels (130 vs. 245 mg/dL, p=0.008), had more frequent history of intracerebral hemorrhage (ICH), and had higher mortality rate (48.6% vs. 19.2%, p=0.020) than that of patients without CVT. In multivariable analysis, the possibility of presence of CVT was higher in younger age groups [odd ratio (OR): 0.91, 95% confidence interval (CI): (0.86-0.97, p<0.001)] and those with accompanying intracerebral hemorrhage (ICH) (OR: 13.60, 95% CI (1.28-144.12, p=0.045). CONCLUSIONS: Our study demonstrated that CVT related to ChAdOx1 nCoV-19 vaccination was associated with younger age, low levels of fibrinogen, presence of ICH and more frequent mortality compared to those of non-CVT. If TTS occurs after ChAdOx1 nCoV-19 vaccination, the presence of CVT in patients with young age or ICH should be considered.
ABSTRACT
This paper is concerned with power transformations in estimating GARCH volatility. To handle a semiparametric case for which the exact likelihood is not known, quasi-likelihood (QL) rather than maximumlikelihood method is investigated to best estimate GARCH via maximizing the information criteria. A power transformation is introduced in the innovation generating QL estimating functions and then optimum power is selected by maximizing the profile information. A combination of two different power transformations is also studied in order to increase the parameter estimation efficiency. Nine domestic stock prices data are analyzed to order to illustrate the main idea of the paper. The data span includes Covid-19 pandemic period in which financial time series are really volatile.
ABSTRACT
OBJECTIVE: To perform a systematic review of case reports or case series regarding thrombosis with thrombocytopenia syndrome (TTS) and cerebral venous thrombosis (CVT) related to ChAdOx1 nCoV-19 vaccination to address the clinical features, laboratory findings, treatment modalities, and prognosis related with CVT. SUBJECTS AND METHODS: We included 64 TTS patients from 19 articles, 6 case series and 13 case reports, in which thrombosis occurred after the first dose of ChAdOx1 nCoV-19 vaccination published up to 30 June 2021 in Embase, ePubs, Medline/PubMed, Scopus, and Web of Science databases. RESULTS: Of the 64 TTS patients, 38 (59.3%) had CVT. Patients with CVT were younger (median 36.5 vs. 52.5 years, p<0.001), had lower fibrinogen levels (130 vs. 245 mg/dL, p=0.008), had more frequent history of intracerebral hemorrhage (ICH), and had higher mortality rate (48.6% vs. 19.2%, p=0.020) than that of patients without CVT. In multivariable analysis, the possibility of presence of CVT was higher in younger age groups [odd ratio (OR): 0.91, 95% confidence interval (CI): (0.86-0.97, p<0.001)] and those with accompanying intracerebral hemorrhage (ICH) (OR: 13.60, 95% CI (1.28-144.12, p=0.045). CONCLUSIONS: Our study demonstrated that CVT related to ChAdOx1 nCoV-19 vaccination was associated with younger age, low levels of fibrinogen, presence of ICH and more frequent mortality compared to those of non-CVT. If TTS occurs after ChAdOx1 nCoV-19 vaccination, the presence of CVT in patients with young age or ICH should be considered.
Subject(s)
ChAdOx1 nCoV-19 , Intracranial Thrombosis , Venous Thrombosis , Humans , Cerebral Hemorrhage/complications , ChAdOx1 nCoV-19/adverse effects , Fibrinogen , Intracranial Thrombosis/chemically induced , Risk Factors , Vaccination/adverse effects , Venous Thrombosis/chemically inducedABSTRACT
Purpose: The purpose of this study is to investigate the influence between online purchase e-CRM activities and e-customer satisfaction on e-loyalty. In particular, it focuses on the mediating effect of e-customer satisfaction in the relationship between online purchase e-CRM activities and e-loyalty. Design/methodology/approach: The data was collected from customers who have purchased online products in South Korea for a week. The study used 1307 questionnaires in the quantitative analysis and the proposed research model and a set of hypotheses were tested using a structural equation model (SEM). Findings: The findings of this study indicate that online purchase e-CRM activities (including e-Marketing, e-Sales, e-Support and e-System) have a significant positive impact on e-customer satisfaction. E-Marketing and e-Sales were found to have a statistically significant positive influence on e-loyalty, but e-Support and e-System did not have a statistically significant effect on e-loyalty. This study also found that e-customer satisfaction significantly mediated the link between online purchase e-CRM activities (including e-Marketing, e-Sales, e-Support and e-System) and e-loyalty. Research limitations/implications: The limitation of this study is that since the data only targets customers in their 20s and 40s, it is difficult to say that it represents customers of all ages. Therefore, it is necessary to carry out research on e-CRM activities for customers of different ages who have experience in online purchasing in the future. Moreover, as the e-commerce market using digital technology grows, companies need to preemptively re-spond to the expansion of "untact" (non-face-to-face) services in the post-COVID-19 era. Therefore, the results of this study presented theoretical and practical implications for improving online purchase e-CRM activities, e-custom-er satisfaction, and e-loyalty to e-commerce companies. Originality/value: The recent COVID-19 pandemic has caused great losses and considerable difficulties in various industries around the world, but to overcome this, the e-commerce market has expanded and has led to the advance-ment of the digital transformation era. Therefore, the originality of this study suggested the importance of e-CRM activities reflecting the purchasing trend of the online market in line with the trend of the Fourth Industrial Revolution and IT era, and it is significant in that it provides theoretical and managerial marketing and strategic implications for better recognition and utilization of these e-CRM activities from corporate and customer perspectives. © 2022 People and Global Business Association.
ABSTRACT
Background: Demand for alcohol-based products, including gel- and aqueous-type hand sanitizers, room sprays, and mouthwashes, has rapidly increased during the ongoing COVID-19 pandemic because of their microbicidal properties. However, toxic methanol can be found from the intentional addition of methanol by manufacturers and invariable production during the manufacturing of alcohol (ethanol). Although the FDA has recommended that such products should contain less than 630 ppm of methanol, it is only a temporary measure established specifically to regulate such products during the current COVID-19 pandemic and hence is not strictly regulated. Objective: This study aims to detect and quantify the level of methanol in alcohol-based products. However, some manufacturers unethically add methanol to their products and promote them as methanol-free. Besides, they do not provide proficiency and toxicity test results. Therefore, these kinds of products need to be analyzed to determine if they are acceptable to use. Methods: This study qualitatively and quantitatively investigates the amount of methanol in commercial alcohol-based products using a newly developed headspace gas chromatography/mass spectrometry method. Moreover, alcoholic beverages which contain methanol are analyzed to be compared with the levels of methanol in alcohol-based products and determine if their methanol levels are acceptable. Results: Methanol concentrations in gel-type hand sanitizers (517 ppm) and mouthwashes (202 ppm) were similar to those in white wine (429 ppm) and beer (256 ppm), respectively, while that of aqueous-type hand sanitizers (1139 ppm) was 1.5 times more than that of red wine (751 ppm). Conclusion: Methanol levels in most of the alcohol-based products did not exceed the FDA-recommended limit.