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Background Frailty is associated with aging, which has recently become a health issue needs to be addressed urgently in the aging population. Neutrophil-to-lymphocyte ratio (NLR) and red cell distribution width (RDW) are novel inflammatory markers that are readily available clinically. Understanding the association of them with frailty is helpful to identify and monitor the development of frailty. There are few studies on the association of NLR and RDW with frailty, and they are not appropriate for traditional meta-analysis due to great heterogeneity between the study results. Objective To perform a scoping review of studies on NLR and RDW as potential biomarkers of frailty, so as to provide a reference for clarifying the pathogenesis of frailty and developing or improving frailty-related assessment tools. Methods Studies on the association of NLR and RDW with frailty were searched in eight databases (PubMed, Embase, Cochrane Library, Web of Science, CNKI, Wanfang Data, VIP and SinoMed) from inception to March 1, 2022. The studies on NLR and RDW as potential biomarkers of frailty was independently screened by two investigators, and the first author, publication time, country or region of publication, sample information, study methods, assessment tools, and assessment results were extracted. The quality of the literature was assessed using the Newcastle-Ottawa Scale and the AHRQ checklist for cross-sectional studies. Results A total of fourteen studies were enrolled, including five cross-sectional studies, four longitudinal studies, one cohort study and four case-control studies, which were all rated≥4 points in terms of methodological quality, indicating that they were high quality. Nine studies examined the association between NLR and frailty, and seven of them showed that elevated NLR was independently associated with increased risk of frailty, and could predict its progression. Seven studies analyzed the association between RDW and frailty, and five of them showed that elevated RDW was independently associated with increased risk of frailty, and could predict its progression. Conclusion Some studies have shown that the risk of frailty increased with the elevation of NLR or RDW in different populations, and its progression could be predicted by NLR or RDW. As potential biomarkers of frailty, NLR and RDW could provide evidence for the pathogenesis of frailty, and a new theoretical basis for the development or improvement of frailty assessment tools. However, the optimal cut-off value of both for predicting frailty in different age groups and sex groups needs to be studied further.

To reduce knock and keeping low NOx emissions and high indicated thermal efficiency (ITE) in a hydrogen fuel engine, the comprehensive effects of ammonia substitution rate (ASR), compression ratio (CR), and ignition timing (IT) on its combustion and its NOx emissions were studied numerically. Based on a four‐cylinder gasoline direct injection (GDI) engine, it was modified into an ammonia/hydrogen dual‐fuel (AHDF) spark ignition (SI) engine. The simulation was conducted by GT‐Power software, and simulation data were validated through experiments. 2500 rpm_50% load was selected for the research. ASR, CR and IT vary from 0% to 20%, 10.5 to 8.5, and −24 to 0°CA ATDC, respectively. The findings indicate that increasing ASR decreases the maximum pressure rise rate (MPRR) and the knock index (KI), improving the ITE, but increasing NOx emissions. Based on 20% ASR, CR was optimized. The findings indicate that decreasing CR reduces the MPRR and KI, but increasing NOx emissions and decreasing the ITE. Finally, based on CR of 9, IT was optimized. The findings indicate that delaying IT reduces the MPRR and KI, but also has a certain impact on NOx emissions and ITE. After compromise consideration, the optimal IT in this study was selected as −9°CA ATDC. [ABSTRACT FROM AUTHOR]