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In this paper, the flow characteristics of a continuous-type liquid–liquid pintle injector are described, focusing on the differential impact of a non-uniform center-flow distribution on single- and bi-injection methodologies as well as the cavitation effect on the spray angle. Using cold-flow experiments, jet-type flows of the center propellant caused by a non-uniform flow distribution were observed during a single injection. This resulted in an augmented pressure drop, as opposed to the flow characteristics of uniform single-film injection. By contrast, bi-injection modalities exhibited a substantial reduction in the pressure drop of the center propellant, underscoring a more equitable flow distribution. Moreover, the occurrence of cavitation in the center propellant was found to markedly affect the spray angle. By considering the injection exit area reduction caused by cavitation, the spray-angle prediction accuracy increased. The findings of this study are expected to reveal the interplay between flow distribution and pressure drop as well as that between cavitation and the spray angle in pintle injectors. Through this understanding, this study provides crucial considerations for the development of more efficient propulsion systems.

OBJECTIVES The aim of this study was to investigate the prevalence and risk factors of poor mental health in the general Korean population during the coronavirus disease 2019 (COVID-19) pandemic. METHODS This cross-sectional, population-based, online survey-based study was conducted from November 5 to 20, 2020 and included adults aged 20-49 years in Chungnam Province, Korea. A total of 549 adults were included. RESULTS In total, 18.8% of the participants had symptoms of depression, 10.6% had symptoms of anxiety, and 5.1% had a high level of perceived stress during the COVID-19 pandemic. Higher levels of stress (odds ratio [OR], 3.13; 95% confidence interval [CI], 1.13 to 8.67), anxiety (OR, 2.33; 95% CI, 1.09 to 4.49), and depression (OR, 3.00; 95% CI, 1.64 to 5.50) were found among never married, widowed, divorced, and separated people than among married/cohabiting/partnered participants. Participants who felt increased stress at home during the COVID-19 outbreak reported more depression (OR, 2.45; 95% CI, 1.49 to 4.05) and anxiety (OR, 2.42; 95% CI, 1.31 to 4.50). Women had higher risks of anxiety (OR, 1.97; 95% CI, 1.09 to 3.58) and stress (OR, 6.40; 95% CI, 2.30 to 17.85) than men. Participants with the highest household income were less likely to report symptoms of stress than those with the lowest household income (OR, 0.24; 95% CI, 0.06 to 0.96). CONCLUSIONS The participants in this study exhibited poor mental health index scores, suggesting that some people are at risk for mental health problems during the COVID-19 pandemic. Being married was independently and significantly associated with a lower likelihood of depression, anxiety, and stress.

Protein synthesis is strictly regulated during replicative aging in yeast, but global translational regulation during replicative aging is poorly characterized. To conduct ribosome profiling during replicative aging, we collected a large number of dividing aged cells using a miniature chemostat aging device. Translational efficiency, defined as the number of ribosome footprints normalized to transcript abundance, was compared between young and aged cells for each gene. We identified more than 700 genes with changes greater than twofold during replicative aging. Increased translational efficiency was observed in genes involved in DNA repair and chromosome organization. Decreased translational efficiency was observed in genes encoding ribosome components, transposon Ty1 and Ty2 genes, transcription factor HAC1 gene associated with the unfolded protein response, genes involved in cell wall synthesis and assembly, and ammonium permease genes. Our results provide a global view of translational regulation during replicative aging, in which the pathways involved in various cell functions are translationally regulated and cause diverse phenotypic changes.

This study analyzed the type and frequency of physical activity that most effectively reduces the homeostatic model assessment of insulin resistance (HOMA2-IR) among adults (≥19 years) in Asia. We used national representative data from 1645 men and 2272 women who participated in the Korea National Health and Nutrition Examination Survey in 2015 were included in the analysis. The effects of different types and frequencies of physical activity on HOMA2-IR were investigated using a multiple regression analysis. Compared with no activity, moderate-to-vigorous physical activity (MVPA) ≥5 times per week (β: -0.214, p≤0.0198) and walking and MVPA ≥5 times per week (β: -0.183, p≤0.0049) were negatively associated with HOMA2-IR. In the subgroup analysis, the strongest effect was observed among overweight men. Additionally, walking plus MVPA ≥5 times per week had the strongest effect on men with a higher-than-recommended daily calorie intake (β: -0.350, p≤0.0030). Therefore, in conclusion, the appropriate type and frequency of physical activity can help reduce HOMA2-IR in South Korean men, especially those who are overweight and/or have a higher-than-recommended daily calorie intake. [ABSTRACT FROM AUTHOR]