Self-Assembly Approach Towards MoS2-Embedded Hierarchical Porous Carbons for Enhanced Electrocatalytic Hydrogen Evolution

Transition metal-based nanoparticle-embedded carbon materials have received increasing attention for constructing next-generation electrochemical catalysts for energy storage and conversion. However, designing hybrid carbon materials with controllable hierarchical micro/mesoporous structures, excellent dispersion of metal nanoparticles, and multiple heteroatom-doping remains challenging. Here, a novel pyridinium-containing ionic hypercrosslinked micellar frameworks (IHMFs) prepared from the core–shell unimicelle of s-poly(tert-butyl acrylate)-b-poly(4-bromomethyl) styrene (s-PtBA-b-PBMS) and linear poly(4-vinylpyridine) were used as self-sacrificial templates for confined growth of molybdenum disulfide (MoS₂) inside cationic IHMFs through electrostatic interaction. After pyrolysis, MoS₂-anchored nitrogen-doped porous carbons possessing tunable hierarchical micro/mesoporous structures and favorable distributions of MoS₂ nanoparticles exhibited excellent electrocatalytic activity for hydrogen evolution reaction as well as small Tafel slope of 66.7 mV dec⁻¹, low onset potential, and excellent cycling stability under acidic condition. Crucially, hierarchical micro/mesoporous structure and high surface area could boost their catalytic hydrogen evolution performance. This approach provides a novel route for preparation of micro/mesoporous hybrid carbon materials with confined transition metal nanoparticles for electrochemical energy conversion.     

Light-Driven Syngas Production over Defective ZnIn2S4 Nanosheets

Photocatalytic syngas (CO and H₂) production with CO₂ as gas source not only ameliorates greenhouse effect, but also produces valuable chemical feedstocks. However, traditional photocatalytic systems require noble metal or suffers from low yield. Here, we demonstrate that S vacancies ZnIn₂S₄ (V_S-ZnIn₂S₄) nanosheets are an ideal photocatalyst to drive CO₂ reduction into syngas. It is found that building S vacancies can endow ZnIn₂S₄ with stronger photoabsorption, efficient electron–hole separation, and larger CO₂ adsorption, finally promoting both hydrogen evolution reaction (HER) and CO₂ reduction reaction (CO₂RR). The syngas yield of CO and H₂ is therefore significantly increased. In contrast to pristine ZnIn₂S₄, the syngas yield over V_S-ZnIn₂S₄ can be improved by roughly ≈4.73 times and the CO/H₂ ratio is modified from 1:4.18 to 1:1. Total amount of syngas after 12 h photocatalysis is as high as 63.20 mmol g⁻¹ without use of any noble metals, which is even higher than those of traditional noble metal-based catalysts in the reported literatures. This work demonstrates the critical role of S vacancies in mediating catalytic activity and selectivity, and highlights the attractive ability of defective ZnIn₂S₄ for light-driven syngas production.     

Static Retention of Dynamic Chiral Arrangements for Achiral Shear Thinning Metal–Organic Colloids

Chiral compounds are known to be important not only because they are the fundamental components of living organisms, but also for their unique chiroptical properties. In recent years, scientists have fabricated several chiral organic supramolecular aggregates by using chiral physical fields, such as vortex flow. Herein, the relationship between dynamic chiroptical properties and rheological nature is discussed, suggesting the shear thinning properties of non-Newtonian fluids might help colloidal particles adopt a chiral arrangement in vortices. Furthermore, the storage modulus of colloids could be increased by adding a linking agent, which successfully kept the dynamic chiroptical properties in the static state. Moreover, the salt effect on the host–guest interaction involved in the colloids was studied, the results suggested a significant enhancement of the transferred dynamic circular dichroism for the achiral guest molecule.     

Splenectomy improves liver fibrosis via tumor necrosis factor superfamily 14 (LIGHT) through the JNK/TGF-β1 signaling pathway

Splenectomy has been reported to improve liver fibrosis in patients with cirrhosis and hypersplenism. However, the mechanisms remain unclear. Tumor necrosis factor superfamily 14 (TNFSF14; also known as LIGHT) is highly expressed in the context of fibrosis and promotes disease progression in patients with fibrotic diseases such as pulmonary and skin fibrosis. Here, we determined whether splenectomy controls the production of LIGHT to improve liver fibrosis. Splenectomy reduced serum LIGHT levels in cirrhotic patients with hypersplenism and a ConA-induced liver fibrosis mouse model. Blocking LIGHT resulted in the downregulation of TGF-β1 in RAW264.7 cells. LIGHT treatment of RAW264.7 and JS1 cells in coculture regulated transforming growth factor-β1 (TGF-β1) expression through the activation of JNK signaling. Small interfering RNA-mediated silencing of lymphotoxin β receptor (LTβR) in macrophages resulted in pronounced decreases in the levels of fibrosis and αSMA in JS1 cells. These results indicated that LIGHT bound to LTβR and drove liver fibrosis in vitro. Blocking TGF-β1 abolished the effect of LIGHT in vitro. Furthermore, the administration of recombinant murine LIGHT protein-induced liver fibrosis with splenectomy, while blocking LIGHT without splenectomy improved liver fibrosis in vivo, revealing that the decrease in fibrosis following splenectomy was directly related to reduced levels of LIGHT. Thus, high levels of LIGHT derived from the spleen and hepatic macrophages activate JNK signaling and lead to increased TGF-β1 production in hepatic macrophages. Splenectomy attenuates liver fibrosis by decreasing the expression of LIGHT.Subject terms: Tumour-necrosis factors, Liver fibrosis, Hepatic stellate cells, Liver cirrhosis, Experimental models of disease     

Fluorescence assay for monitoring Zn-deficient superoxide dismutase in vitro

A method has been developed for selective detection of the zinc-deficient form of Cu, Zn superoxide dismutase (SOD1) in vitro. Zinc-deficient SOD1 mutants have been implicated in the death of motor neurons leading in amyotrophic lateral sclerosis (ALS or Lou Gerhig's disease). Thus, this method may have applicability for detecting zinc-deficient SOD1 mutants in human ALS patients samples as well as in a transgenic mouse model of ALS and in cultured motor neurons. We determined previously that structural analogs of 1,10 phenanthroline, which react specifically with Cu(I), react with the active Cu(I) of SOD1 when zinc is absent, but not when zinc is also bound, as evidenced by the fact that the reaction is inhibited by pretreatment of the enzyme with zinc. We report herein that bathocuproine, or its water-soluble derivative bathocuproine disulfonate, react with zinc-deficient SOD1 to form a complex which fluoresces at 734 nm when excited at 482 nm. Fluorescent intensity is concentration dependent, thus we propose to use fluorescent confocal microscopy to measure intracellular levels of zinc-deficient SOD1 in situ.     

In Situ Observation of Dynamic Galvanic Replacement Reactions in Twinned Metallic Nanowires by Liquid Cell Transmission Electron Microscopy

Galvanic replacement is a versatile approach to prepare hollow nanostructures with controllable morphology and elemental composition. The primary issue is to identify its fundamental mechanism. In this study, in situ liquid cell transmission electron microscopy was employed to monitor the dynamic reaction process and to explore the mechanism of galvanic replacement. The detailed reaction process was revealed based on in situ experiments in which small Au particles first appeared around Ag nanowires; they coalesced, grew, and adhered to Ag nanowires. After that, small pits grew from the edge of Ag nanowires to form tubular structures, and then extended along the Ag nanowires to obtain hollowed structures. All of our experimental observations from the viewpoint of electron microscopy, combined with DFT calculations, contribute towards an in‐depth understanding of the galvanic replacement reaction process and the design of new materials with hollow structures.     

DNA修饰碱基5-甲基胞嘧啶和8-羟基鸟嘌呤的毛细管气相色谱分析及质谱鉴定

 探索了GC/FID定量分析DNA修饰碱基 5 甲基胞嘧啶和 8 羟基鸟嘌呤的实验条件 ,用GC/MS鉴定各有关成分。结果表明 ,DNA水解物中不同成分可被成功地衍生和分离 ;5 甲基胞嘧啶和 8 羟基鸟嘌呤的相对摩尔反应因子分别为 3 0和 1 3;灵敏度分别为 5 50× 1 0 9mV·s/ g和 7 59× 1 0 1 0 mV·s/ g ;检测限可分别达 36 4pg/s和 1 5 8pg/s ;整个分析流程的相对标准偏差小于 2 0 %。     

Hydrophobically modified polyelectrolytes III. Reactivity ratio determination of FX14/AA,LA/AA and SA/AA

The reactivity ratios of three hydrophobic monomers, FX14, LA and SA, to hydrophilic monomer, acrylic acid (AA), were determined. For the fluorocarbon containing hydrophobic monomer FX14, elemental analysis was adopted to obtain the relative content of FX14 to AA. For two hydrocarbon monomers, ¹³C NMR was used. FR, KT linear method and EVM nonlinear method were applied in calculating reactivity ratios. It is found that the reactivity of LA and SA is lower than that of AA, for solution polymerization in cyclohexane. Whereas FX14 is more reactive than AA in benzene. Finally, the distribution of small amounts of these hydrophobic monomers along the polymeric chain is discussed and a random sequence is confirmed