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Sarcopenia is an important indicator of ill health and is linked to increased mortality and a reduced quality of life. Age‐associated muscle mass indices provide a critical tool to help understand the development of sarcopenia. This study aimed to develop sex‐ and age‐specific percentiles for muscle mass indices in a Chinese population and to compare those indices with those from other ethnicities using the National Health and Nutrition Examination Survey (NHANES) data. Whole‐body and regional muscle mass was measured by dual‐energy X‐ray absorptiometry (DXA) in participants of the China Body Composition Life‐course (BCL) study (17 203 healthy Chinese aged 3–60 years, male 48.9%) and NHANES (12 663 healthy Americans aged 8–59 years, male 50.4%). Age‐ and sex‐specific percentile curves were generated for whole‐body muscle mass and appendicular skeletal muscle mass using the Generalized Additive Model for Location Scale and Shape statistical method. Values of upper and lower muscle mass across ages had three periods: an increase from age 3 to a peak at age 25 in males (with the 5th and 95th values of 41.5 and 66.4 kg, respectively) and age 23 in females (with the 5th and 95th values of 28.4 and 45.1 kg, respectively), a plateau through midlife (30s–50s) and then a decline after their early 50s. The age at which muscle mass began to decline was 52 years in men with the 5th and 95th percentile values of 43.5 and 64.6 kg, and 51 years in women with the 5th and 95th percentile values of 31.6 and 46.9 kg. Appendicular skeletal muscle mass decreased earlier than whole body muscle mass, especially leg skeletal muscle mass, which decreased slightly after age 49 years in both sexes. In comparison with their US counterparts in the NHANES, the Chinese participants had lower muscle mass indices (all P< 0.001) and reached a muscle mass peak earlier with a lower muscle mass, with the exception of similar values compared with adult Mexican and White participants. The muscle mass growth rate of Chinese children decreased faster than that of other races after the age of 13. We present the sex‐ and age‐specific percentiles for muscle mass and appendicular skeletal muscle mass by DXA in participants aged 3–60 from China and compare them with those of different ethnic groups in NHANES. The rich data characterize the trajectories of key muscle mass indices that may facilitate the clinical appraisal of muscle mass and improve the early diagnosis of sarcopenia in the Chinese population.

AbstractAs a new urbanization mode, smart cities provide a way to achieve the mutually beneficial situation of both economic development and environmental protection. As such, the question of whether and how smart-city construction can promote the high-quality development of urban economies is worth considering. By measuring the green total factor productivity (GTFP) of 233 cities in China from 2004–2019, this paper adopts the national pilot smart cities of China as a quasi-experiment and constructs a time-varying DID model to explore the direct, dynamic, and heterogeneity influence of smart-city construction on GTFP. The results indicate the following: (1) Smart-city construction can significantly promote the urban GTFP, which is mainly caused by the progress of green technology, and the effect is robust after a series of robustness tests; (2) smart-city construction can contribute to GTFP improvement primarily through accelerating technological innovation, promoting industrial upgrading, and realizing resource allocation optimization; and (3) smart cities that are larger in scale, have a higher administrative rank, and lie in eastern regions have stronger positive effects on GTFP. This study aims to contribute to the promotion of urban sustainable development.

It is meaningful to exploit copper sulfide materials with desired structure as well as potential application due to their cheapness and low toxicity. A low-temperature and facile solvothermal method for preparing three-dimensional (3D) hierarchical covellite (CuS) microspheres from an ionic liquid precursor [Bmim]2Cu2Cl6(Bmim = 1-butyl-3-methylimidazolium) is reported. The formation of CuS nanostructures was achieved by decomposition of intermediate complex Cu(Tu)3Cl (thiourea = Tu), which produced CuS microspheres with diameters of 2.5–4 μm assembled by nanosheets with thicknesses of 10–15 nm. The ionic liquid, as an “all-in-one” medium, played a key role for the fabrication and self-assembly of CuS nanosheets. The alkylimidazolium rings ([Bmim]+) were found to adsorb onto the (001) facets of CuS crystals, which inhibited the crystal growth along the [001] direction, while the alkyl chain had influence on the assembly of CuS nanosheets. The CuS microspheres showed enhanced electrochemical performance and high stability for the application in supercapacitors due to intriguing structural design and large specific surface area. When this well-defined CuS electrode was assembled into an asymmetric supercapacitor (ASC) with an activated carbon (AC) electrode, the CuS//AC-ASC demonstrated good cycle performance (∼88% capacitance after 4000 cycles) and high energy density (15.06 W h kg–1at a power density of 392.9 W kg–1). This work provides new insights into the use of copper sulfide electrode materials for asymmetric supercapacitors and other electrochemical devices.

The autoregressive integrated moving average (ARIMA) model is one of the stochastic time series methods to predict the hepatitis incidence. Considering the Box-Jenkins modelling approach, the incidence of hepatitis was collected monthly from 2004 to 2010 in Qian’an and a model (SARIMA) was fit. Then, this model was used for calculating hepatitis incidence for the last six observations compared with observed data. The constructed model was performed to predict the monthly incidence in 2011. The model SARIMA(0,1,1)(0,1,1) 12 was established finally and the residual sequence was a white noise sequence. It is necessary and practical to apply the approach of ARIMA model in fitting time series to predict hepatitis within a short lead time.