The association between physical activity intensity and frailty risk among older adults across different age groups and genders: Evidence from four waves of the China Health and Retirement Longitudinal Survey.

"Exercise is the best medicine" is well known, but the optimal dose of physical activity (PA) for males and females across different age groups is still unknown. This study, using data from the four waves of CHARLS, aimed to determine the optimal PA dose that reduces frailty risks among older adults across various age groups and both sexes. We created a frailty index score using 63 health-related variables and used 0.21 as the frailty cut point. Binary logistic regression was used to compare the effect of vigorous, moderate, and light intensity PA under IPAQ criteria on frailty risk. The study found that regardless of whether males or females, the optimal effect of vigorous-intensity PA in reducing the risk of frailty is consistently observed throughout the entire old age career. Moreover, the age groups at which moderate-intensity PA reduces the risk of frailty were from age 70 for males and from age 80 for females. And light-intensity PA had no effect on reducing the risk of frailty. Moderate and vigorous intensity of PA in older adults should be promoted, but guidelines and recommendations must account for optimal associations with PA dose across genders and age groups.

Enhanced mechanical strength of a highly de-lithiated single-crystal Ni-rich cathode to suppress irreversible planar gliding.

The mechanical properties of de-lithiated single-crystal Ni-rich cathodes are causing extensive concern. Here, we first show that the compression hardness of single crystal Ni-rich cathode particles decreases significantly at highly de-lithiated states by micro-compression testing. Thus, phase-boundary hardening was introduced to inhibit the planar gliding, resulting in excellent electrochemical performance.

Multifunctionality of cerium decoration in enhancing the cycling stability and rate capability of a nickel-rich layered oxide cathode.

The structural collapse and surface chemical degradation of nickel-rich layered oxide cathodes (NCM) of lithium-ion batteries during operation, which result in severe capacity attenuation, are the major challenges that hinder their commercial development. To improve the cycle and rate performances of LiNi0.8Co0.1Mn0.1O2 (NCM811), in this study, we have constructed a double-shell structure protective layer with a surface CeO2-x coating and interfacial spinel-like phase, which mitigate particle microcrack formation and isolate the NCM811 particles from electrolyte erosion. Additionally, during heat-treatment calcination, tetravalent cerium ions with strong oxidation ability can be partially doped into the material, which causes partial oxidation of Ni2+ to Ni3+, thereby reducing the Li+/Ni2+ mixing. The strong Ce-O bonds formed in the lattice help to improve the stability of the structure in the highly de-lithiated state. Thus, the synergy of multifunctional cerium modification effectively improves the structural stability and electrochemical kinetics of the material during cycling. Impressively, the obtained Ce-NCM811 exhibits capacity retention of 80.3% at a high discharge rate of 8 C after 500 cycles, which is much higher than that of the pristine cathode (only 44.3%). This work successfully designed a material with multi-functional Ce modification to provide a basis for Ni-rich cathode materials, which is crucial as it effectively improves the electrochemical performance.