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1.
Children (Basel) ; 11(6)2024 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-38929214

RESUMEN

Cyberbullying has emerged as a pervasive problem among high school students, with potentially severe consequences for their mental well-being. This study aimed to investigate the prevalence, risk factors, and associations of cyberbullying with stress and mental well-being among high school students in Zagazig, Egypt. A cross-sectional study was conducted among 562 high school students using a random sampling technique. The data were collected using a self-administered questionnaire that included the Cyberbullying Scale, Perceived Stress Scale (PSS-10), and General Health Questionnaire (GHQ-12). Descriptive statistics, independent samples t-tests, multiple regression, mediation, and logistic regression analyses were employed for data analysis. The prevalence of cyberbullying victimization was 38.3%, with 20.6% exposed to two or three cyberbullying behaviors and 4.1% exposed to four or more. Female students, those under 18 years old, those with lower educational achievement, and those with higher daily internet use were more likely to experience cyberbullying. Cyberbullied students reported significantly higher levels of perceived stress and poorer mental well-being compared to non-cyberbullied students. Perceived stress likely mediated the relationship between cyberbullying victimization and general psychological health. Cyberbullying is a significant problem among high school students in Zagazig, Egypt, with detrimental effects on their stress levels and mental well-being. Targeted interventions and prevention strategies are needed to address cyberbullying and promote the well-being of adolescents in the digital age.

2.
Int J Vent ; 23(2): 104-124, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38799196

RESUMEN

We compare two aerosol surrogate tracers in aircraft cabins for breathing and coughing sources: tracer gas collected in the ACER Boeing 767 mock-up and fluorescent particles collected in an actual Boeing 767 aircraft by the US Transportation Command (TRANSCOM). Each source was located individually in window and middle seats. Exposure generally decreased with source distance. A window seat breathing source resulted in good agreement between datasets for exposure (as percent of release) for the TRANSCOM hangar-AFT testing mode, which corresponds to the 11-row cabin ACER laboratory space. Average tracer gas exposure for a middle seat breathing source was higher in the ACER study than the fluorescent particle tracer exposure in the TRANSCOM study. Using a coughing source in a window seat, the exposure for the TRANSCOM data was higher within the first two rows from the source before decreasing to and tracking with the ACER levels, until increasing after about 5 m away. A similar trend was recorded for a middle seat coughing source with higher overall exposure for the TRANSCOM data. Sources of exposure variation between the studies include particle deposition. This work helps optimize aerosol dispersion research in aircraft cabins and provides some validation to the existing studies.

3.
Sci Rep ; 14(1): 6381, 2024 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-38493222

RESUMEN

In a bid to address the energy-intensive nature of primary aluminum production, this study explores the solid-state recycling of aluminum alloy 6082 chips through direct hot extrusion. Compacted at room temperature, chips were extruded at temperatures (350, 425, and 500 °C) and reduction ratios (6, 8.5, and 11) to optimize mechanical properties. Extensive analyses, including ANOVA and linear regressions, of strength, density, and microstructure revealed significant influences of those extrusion parameters. Optimizing these parameters within the study's aforementioned working ranges can impact the recycled material's strength; with a 36% reduction ratio increase and 20% temperature increase modestly reducing ultimate strength (2%), while a 20% temperature increase alone lowers yield strength more noticeably (9%). These findings highlight the potential for enhanced recycling and sustainable manufacturing.

4.
Eng Rep ; : e12582, 2022 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-36718395

RESUMEN

Aircraft cabins have high-performance ventilation systems, yet typically hold many persons in close proximity for long durations. The current study estimated airborne virus exposure and infection reductions when middle seats are vacant compared to full occupancy and when passengers wear surgical masks in aircraft. Tracer particle data reported by U.S. Transportation Command (TRANSCOM) and CFD simulations reported by Boeing were used along with NIOSH data, to build nonlinear regression models with particle exposure and distance from particle source as variables. These models that estimate exposure at given distances from the viral source were applied to evaluate exposure reductions from vacant middle seats. Reductions averaged 54% for the seat row where an infectious passenger is located and 36% for a 24-row cabin containing one infectious passenger, with middle seats vacant. Analysis of the TRANSCOM data showed that universal masking (surgical masks) reduced exposures by 62% and showed masking and physical distancing provide further reductions when practiced together. For a notional scenario involving 10 infectious passengers, compared with no intervention, masking, distancing, and both would prevent 6.2, 3.8, and 7.6 secondary infections, respectively, using the Wells-Riley equation. These results suggest distancing alone, masking alone, and these practiced together reduce SARS CoV-2 exposure risk in increasing order of effectiveness, when an infectious passenger is present.

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