Effect of synthesis temperature on the structural morphology of a metal-organic framework and the capacitor performance of derived cobalt-nickel layered double hydroxides.

Three-dimensional interconnected nickel-cobalt layered double hydroxides (NiCo-LDHs) were prepared on nickel foam by ion exchange using a cobalt-based metal-organic framework (Co-MOF) as a template at different temperatures. The effects of the Co-MOF preparation temperature on the growth, mass, morphology, and electrochemical properties of the Co-MOF and derived NiCo-LDH samples were studied. The synthesis temperature from 30 to 50 °C gradually increased the mass of the active material and the thickness of the Co-MOF sheets grown on the nickel foam. The higher the temperature is, the larger the proportion of Co3+. ß-Cobalt hydroxide (ß-Co(OH)2) sheets were generated above 60 °C. The morphology and mass loading pattern of the derived flocculent layer clusters of NiCo-LDH were inherited from metal-organic frameworks (MOFs). The areal capacitance of NiCo-LDH shows an inverted U-shaped curve trend with increasing temperature. The electrode material synthesized at 50 °C had a tremendous specific capacitance of 7631 mF·cm-2 at a current density of 2 mA·cm-2. The asymmetric supercapacitor assembled with the sample and active carbon (AC) achieved an energy density of 55.0 Wh·kg-1 at a power density of 800.0 W·kg-1, demonstrating the great potential of the NiCo-LDH material for energy storage. This work presents a new strategy for designing and fabricating advanced green supercapacitor materials with large power and energy densities.

The health benefit of physical exercise on COVID-19 pandemic: Evidence from mainland China.

OBJECTIVES: Our study aims to investigate the health benefit of regular physical exercise participation on a series of COVID-19 outcomes including COVID-19 morbidity, mortality, and cure rate. METHODS: Prefecture-level panel data related to physical exercise and the COVID-19 pandemic in China were collected from January 1 to March 17, 2020, (N = 21379). Multiple linear regression was conducted, and the ordinary least squares technique was used to estimate the coefficient. RESULTS: It was shown that regular sports participation significantly negatively affected COVID-19 morbidity (estimate = -1.1061, p<0.01) and mortality (estimate = -0.3836, p<0.01), and positively affected cure rate (estimate = 0.0448, p<0.01), implying that engaging in physical exercise regularly does have a significant positive effect on COVID-19 outcomes. Then, we explored the heterogeneity of the effect of physical exercise on areas with different risk levels and it was revealed that the effect of physical exercise was more pronounced in high-risk areas in terms of morbidity (estimate = -1.8776, p<0.01 in high-risk areas; estimate = -0.0037, p<0.01 in low-risk areas), mortality (estimate = -0.3982, p<0.01 in high-risk areas; estimate = -0.3492, p<0.01 in low-risk areas), and cure rate (estimate = 0.0807, p<0.01 in high-risk areas; 0.0193 = -0.0037, p<0.05 in low-risk areas). CONCLUSIONS: Our results suggest that regularly engaging in physical exercise before the pandemic has positive health effects, especially in the case of a more severe epidemic. Therefore, we urge readers to actively engage in physical exercise so that we can reduce the risks in the event of a pandemic.

Nocardiopsis valliformis sp. nov., an alkaliphilic actinomycete isolated from alkali lake soil in China.

A strain (HBUM 20028(T)) isolated from alkali lake soil in China was studied by a polyphasic taxonomic approach. The strain produced abundant aerial and substrate mycelia. Long spore chains were borne on the aerial mycelium, and the substrate mycelium was often arranged in a shape like a fence or palisade. The special characteristic of strain HBUM 20028(T) was its abundant growth under alkaline conditions, at pH 8.0-14.0. The cell wall of strain HBUM 20028(T) contained meso-diaminopimelic acid but no diagnostic sugar. Major phospholipids included diphosphatidylglycerol and phosphatidylcholine. The major menaquinones were MK-10(H(2)), MK-10(H(4)) and MK-10(H(6)). The major cellular fatty acids were iso-C(16 : 0) (31.66 %), anteiso-C(17 : 0) (14.85 %) and C(18 : 1)omega9c (14.73 %). All of these characters consistently indicated that strain HBUM 20028(T) belongs to the genus Nocardiopsis. DNA-DNA hybridization between the strain and type strains of related species gave relatedness values far below 70 %. Based on 16S rRNA gene sequence analysis, DNA relatedness and phenotypic characteristics, a novel species with the name Nocardiopsis valliformis sp. nov. is proposed. The type strain is HBUM 20028(T) (=DSM 45023(T) =CGMCC 4.2135(T)).