Enterococcus faecium GEFA01 alleviates hypercholesterolemia by promoting reverse cholesterol transportation via modulating the gut microbiota-SCFA axis.

This study aimed to identify cholesterol-lowering commensal strains from healthy lean individuals and to evaluate the cholesterol-lowering capacity of Enterococcus faecium GEFA01 in mice fed a high-cholesterol and high-fat diet. E. faecium GEFA01 was isolated from the feces of a healthy lean individual in a selective basal salt medium supplemented with cholesterol. E. faecium GEFA01 exhibited a cholesterol removal rate (CRR) of 46.13% by coprecipitation, assimilation, and degradation of cholesterol. Moreover, E. faecium GEFA01 significantly decreased the body weight of mice and the levels of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), hepatic TC, triglycerides (TG), and LDL-C, and increased serum high-density lipoprotein cholesterol (HDL-C) levels in mice fed a high-cholesterol diet compared with the HCD group. We also observed that E. faecium GEFA01 significantly downregulated the gene expression of HMG-CoA reductase (Hmgcr), Srebp-1c, Fxr, Shp, and Fgf 15, upregulated the gene expression of low-density lipoprotein receptor (Ldlr), Abcg5/8, Abca1, cholesterol 7 alpha-hydroxylase (Cyp7a1), and Lxr in the liver of mice in relative to the HCD group, markedly increased the relative abundance of Lactobacillus, Akkermansia, Bifidobacterium, and Roseburia, and decreased the abundance of Helicobacter in the feces. Collectively, we confirmed that E. faecium GEFA01 exhibited cholesterol-lowering effects in mice fed a high-cholesterol diet, which was achieved through assimilation, coprecipitation, and degradation of cholesterol, and through modulation of the gut microbiota short-chain fatty acid (SCFA) axis that promoted reverse cholesterol transport and bile acid excretion. Our study demonstrated that E. faecium GEFA01 may be used as a probiotic candidate to lower cholesterol levels in the future.

Cyclodextrin-Integrated PEO-Based Composite Solid Electrolytes for High-Rate and Ultrastable All-Solid-State Lithium Batteries.

Poly(ethylene oxide) (PEO)-based composite solid electrolytes (CSEs) are considered as one of the most promising candidates for all-solid-state lithium batteries (ASSLBs). However, a key challenge for their further development is to solve the main issues of low ionic conductivity and poor mechanical strength, which can lead to insufficient capacity and stability. Herein, ß-cyclodextrin (ß-CD) is first demonstrated as a multifunctional filler that can form a continuous hydrogen bond network with the ether oxygen unit from the PEO matrix, thus improving the comprehensive performances of the PEO-based CSE. By relevant characterizations, it is demonstrated that ß-CD is uniformly dispersed into the PEO substrate, inducing adequate dissociation of lithium salt and enhancing mechanical strength through hydrogen bond interactions. In a Li/Li symmetric battery, the ß-CD-integrated PEO-based (PEO-LiTFSI-15% ß-CD) CSE works well at a critical current density up to 1.0 mA cm-2 and retains stable lithium plating/stripping for more than 1000 h. Such reliable properties also enable its superior performance in LiFePO4-based ASSLBs, with specific capacities of 123.6 and 114.0 mA h g-1 as well as about 100 and 81.8% capacity retention over 300 and 700 cycles at 1 and 2 C (1 C = 170 mA g-1), respectively.

An environmentally friendly strategy to prepare nitrogen-rich hierarchical porous carbon for high-performance supercapacitors.

A green route modulated by the addition of CaCl2 during the potassium compound-assisted synthesis is developed for the first time for the synthesis of nitrogen-rich hierarchical porous carbon (NRHPC) with high external surface area and moderate total pore volume. The NRHPCN constructed by nanosheets is capable of simultaneously achieving high gravitational and volumetric capacity for supercapacitors (SCs).

Biomass waste-derived nitrogen-rich hierarchical porous carbon offering superior capacitive behavior in an environmentally friendly aqueous MgSO4 electrolyte.

Nitrogen-doped porous carbons have been extensively investigated to improve the specific capacitance in aqueous electrolytes by increasing the specific surface area and nitrogen content and by optimizing the pore structure. However, research on the effect of electrolyte cations on the specific capacitance of these materials is rare, especially for neutral electrolytes. Herein, a nitrogen-rich hierarchically porous carbon (NRHPC) with a high nitrogen content of 12.3 atm% is successfully prepared by pyrolyzing a mixture of bagasse, K2CO3 and urea in a mass ratio of 2:1:4. It is found that NRHPC shows superior electrochemical performance in MgSO4 than in Li2SO4 electrolyte, with specific capacitances of 315.0, 274.4, and 188.1 F g-1 at 1.0, 10.0, and 100 A g-1, respectively. Furthermore, it is found that the capacitance enhancement is closely related to the nitrogen content of the porous carbon materials. Theoretical calculation reveals that the Mg2+ ions have higher affinity towards the N atoms than Li+, producing higher charge storage capability via interaction between the Mg2+ and N atoms. When the 1.0 M MgSO4 is used as electrolyte, a symmetric capacitor based on the nitrogen-rich hierarchically porous carbon shows a high energy density of 39.5 Wh kg-1 at a power density of 0.9 kW kg-1. Moreover, this as-assembled device displays superior long-term cycling stability, with a capacitance retention of >96.2% after 10,000 cycles at 10.0 A g-1.

An Unprecedented Case: A Low Specific Surface Area Anatase/N-Doped Carbon Nanocomposite Derived from a New Single Source Precursor Affords Fast and Stable Lithium Storage.

A nanocomposite of ultrafine anatase nanoparticles (<5 nm) embedded N-doped carbon (TiO2-NPs/NC) with a relatively low specific surface area was successfully synthesized by in situ pyrolysis of a new and cheap single source precursor of (H2en)3[Ti4(O2)4(Hcit)2(cit)2]·12H2O (en = ethylenediamine and H4cit = citric acid) under 550 °C and an inert atmosphere. The precursor in crystalline state was isolated from an aqueous solution containing of titanium butoxide, citric acid, hydrogen peroxide, and ethylenediamine and was characterized. The crystal structure was determined by X-ray single crystal diffraction. To our surprise, the low surface area TiO2-NPs/NC exhibits a high specific capacity, superior rate capability, excellent cycle performance, and good processability as a negative material for rechargeable lithium-ion batteries (LIBs). A large reversible capacity of 360 and 125 mA h g-1 and a high Coulombic efficiency (the average value is ∼99.8%) could be kept even after 1000 cycles under a current density of 0.3 and 6 A g-1, respectively. An analysis of the voltammetric sweep data shows that the pseudocapacitive behavior occurred at the surface of the material and the lithium intercalation processes contribute to the total stored charge, resulting in the high capacity of the TiO2-NPs/NC nanocomposite. The potentiostatic intermittent titration technique used to determine the lithium ion diffusion (DLi+) suggested the TiO2-NPs/NC nanocomposite displays a high DLi+. In addition, the high electric conductivity provided by the NC substrate and the ultrafine anatase particles can mitigate the diffusion path for electrons and ions and tolerate higher strain, and thus effectively decrease pulverization and improve the rate and cycle performance. In particular, the observed superior lithium storage properties, resulting from the low surface area nanocomposite with ultrafine nanoparticles embedded NC substrate, are expected to have fundamental and practical implications for the preparation of high performance electrodes in LIBs or other cells.