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Recurrent events, including cardiovascular events, are commonly observed in biomedical studies. Understanding the effects of various treatments on recurrent events and investigating the underlying mediation mechanisms by which treatments may reduce the frequency of recurrent events are crucial tasks for researchers. Although causal inference methods for recurrent event data have been proposed, they cannot be used to assess mediation. This study proposed a novel methodology of causal mediation analysis that accommodates recurrent outcomes of interest in a given individual. A formal definition of causal estimands (direct and indirect effects) within a counterfactual framework is given, and empirical expressions for these effects are identified. To estimate these effects, a semiparametric estimator with triple robustness against model misspecification was developed. The proposed methodology was demonstrated in a real‐world application. The method was applied to measure the effects of two diabetes drugs on the recurrence of cardiovascular disease and to examine the mediating role of kidney function in this process. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate breakdown voltage at 1500 V of GaN on a QST power device. The high breakdown voltage and low current collapse performance can be attributed to the higher quality of GaN buffer layers grown on QST substrates. This is primarily due to the matched coefficient of thermal expansion (CTE) with GaN and the enhanced mechanical strength. Based on computer-aided design (TCAD) simulations, the strong electric-field-induced trap-assisted thermionic field emissions (TA-TFEs) in the GaN on QST could be eliminated in the GaN buffer. This demonstration showed the potential of GaN on QST, and promises well-controlled performance and reliability under high-power operation conditions. [ABSTRACT FROM AUTHOR]

(1) Background: An asthma exacerbation that is not relieved with medication typically requires an emergency room visit (ERV). The coronavirus disease 2019 (COVID-19) pandemic began in Taiwan in January of 2020. The influence of the COVID-19 pandemic on pediatric ERVs in Taiwan was limited. Our aim was to survey pediatric asthma ERVs in the COVID-19 era; (2) Methods: Data were collected from the health quality database of the Taiwanese National Health Insurance Administration from 2019 to 2021. Air pollution and climatic factors in Taipei were used to evaluate these relationships. Changes in the rates of pediatric asthma ERVs were assessed using logistic regression analysis. Poisson regression was used to evaluate the impact of air pollution and climate change; (3) Results: The rate of pediatric asthma ERVs declined in different areas and at different hospital levels including medical centers, regional and local hospitals. Some air pollutants (particulate matter ≤ 2.5 µm, particulate matter ≤ 10 µm, nitrogen dioxide, and carbon monoxide) reduced during the COVID-19 lockdown. Ozone increased the relative risk (RR) of pediatric asthma ERVs during the COVID-19 period by 1.094 (95% CI: 1.095–1.12) per 1 ppb increase; (4) Conclusions: The rate of pediatric asthma ERVs declined during the COVID-19 pandemic and ozone has harmful effects. Based on these results, the government could reduce the number of pediatric asthma ERVs through healthcare programs, thereby promoting children's health. [ABSTRACT FROM AUTHOR]

Background:  Oral cavity cancers requiring excision of the oral commissure and free flap reconstruction often requires commissuroplasty to manage oral incontinence. We aimed to evaluate the implications of primary versus delayed commissuroplasty on drooling, and interincisal distance outcomes in this cohort., Methods:  A retrospective query of head and neck cancer patients operated by a single surgeon from 2017 to 2020 was performed. Patients were included if they underwent free flap reconstruction of the oral commissure, had an immediate or delayed commissuroplasty, and had 2 years of follow-up data including Thomas-Stonell and Greenberg drooling rating scales and interincisal distance measurements., Results:  Thirty-five patients were included in the review. Twelve patients received immediate commissuroplasty and 23 patients had delayed commissuroplasty. Interincisal distance was similar at baseline, although significantly varied between immediate and delayed commissuroplasty groups at 1 month and 2 years postoperative. Drooling scores were significantly elevated in the group treated with delayed commissuroplasty, but eventually normalized after staged surgery and follow-up. Patients treated with adjunct radiation therapy had lower interincisal distance than patients who did not have radiation., Conclusion:  Delayed commissuroplasty increased interincisal distance and normalize drooling in patients who required full-thickness excision of the buccal mucosa and oral commissure and free tissue reconstruction. The presented data can help to educate patients on expected postoperative outcomes and likely advocates for a second-stage procedure after completion of adjunct radiotherapy to achieve optimal commissural placement and oral competence., Competing Interests: None declared., (Thieme. All rights reserved.)