Circumventing the OCl versus OOH scaling relation in the chlorine evolution reaction: Beyond dimensionally stable anodes

The development of selective electrocatalysts for the chlorine evolution reaction (CER) is majorly restrained by a scaling relation between the OCl and OOH adsorbates, rendering that active CER catalysts are also reasonably active in the competing oxygen evolution reaction (OER). While theory predicts that the OCl versus OOH scaling relation can be circumvented as soon as the elementary reaction steps in the CER comprise the Cl rather than the OCl adsorbate, it was demonstrated recently that PtN₄ sites embedded in a carbon nanotube follow this theoretical prediction. Advanced experimental analyses illustrate that the PtN₄ sites also reveal a different reaction kinetics compared to the industrial benchmark of dimensionally stable anodes (DSA). A reverse Volmer–Heyrovsky mechanism was identified, in which the rate-determining Volmer step for small overpotentials is followed by the kinetically limiting Heyrovsky step for larger overpotentials. Since the PtN₄ sites excel DSA in terms of activity and chlorine selectivity, we suggest the Cl intermediate as well as the reverse Volmer–Heyrovsky mechanism as the design criteria for the development of next-generation electrode materials beyond DSA.     

Evaluation on bioactivities of triterpenes from Bergenia emeiensis

Bergenia emeiensis is a traditional folk medicine in China. Most studies are focusing on the bioactivity of bergenin, neglecting other compounds. Therefore, in this present work, the antioxidant, antibacterial and anticancer abilities of triterpenes from B. emeiensis rhizomes (TBE) were comprehensively evaluated. The results showed that TBE could well scavenge DPPH with a lower EC50 of 0.29 mg/mL and could improve the cell viability of CHO cells against H₂O₂ induced cell death. Additionally, TBE also enhanced the resistance of C. elegans under thermal stress, exhibiting a strong antioxidant potential in vivo. Moreover, TBE showed a certain antibacterial ability on five kind strains such as Pseudomonas aeruginosa while TBE could not significantly inhibit the growth of plant pathogenic fungi. Furthermore, TBE possessed an excellent suppression ability on the proliferation of cancer cells especially Hela and Hep G2 cells with an IC50 of 41.79 μg/mL and 48.62 μg/mL at 48 h, respectively. After fractionally extracted with petroleum ether, ethyl acetate and ethanol, ethanol phase (EP) contained the most triterpenes, followed by ethyl acetate phase (EAP) and petroleum ether phase (PEP). Besides, EP and EAP exhibited a strong antioxidant capacity and also inhibited the proliferation of Hela and Hep G2 cells with the effect of pro-oxidation by inducing a high level of ROS and decreasing mitochondrial membrane potential, thus causing oxidative stress then inducing cell apoptosis. Therefore, these outcomes indicated the triterpenes from B. emeiensis possessed a strong antioxidant ability and an anticancer effect, thus making B. emeiensis become a promising potential alternative in pharmacological field.     

The mosaic structure design to improve the anchoring strength of SiOx@C@Graphite anode

Silicon oxide (SiO_x)-based anodes have aroused great interest as the most promising alternative anode in the practical application of high-performance lithium-ion batteries. However, the electrochemical performance is inhibited because of the large volume change, and the electrode structure deteriorates during the cycling process, which hinders their practical application. In this article, a novel fabrication method for the synthesis of high-performance SiO_x@C@Graphite composites is presented. SiO_x particles are anchored on the graphite surface by chemical vapor deposition and compression molding. This structure makes up the shortcomings of poor electrical conductivity and poor bonding strength between SiO_x and graphite particles. It is beneficial to form a stable solid electrolyte interface and helps to maintain the structural integrity of electrode materials. As a result, the synthetic SiO_x@C@Graphite anode shows a high reversible capacity (2698.8 mA h), excellent cycle stability (about 76.9% capacity retention for 500 cycles) and a superior rate ability. Our research hopes to provide a new idea for improving the bonding strength of the surface coating.     

Rutin and Quercetin Decrease Cholesterol in HepG2 Cells but Not Plasma Cholesterol in Hamsters by Oral Administration

Rutin (R) and quercetin (Q) are two widespread dietary flavonoids. Previous studies regarding the plasma cholesterol-lowering activity of R and Q generated inconsistent results. The present study was therefore carried out to investigate the effects of R and Q on cholesterol metabolism in both HepG2 cells and hypercholesterolemia hamsters. Results from HepG2 cell experiments demonstrate that both R and Q decreased cholesterol at doses of 5 and 10 µM. R and Q up-regulated both the mRNA and protein expression of sterol regulatory element binding protein 2 (SREBP2), low-density lipoprotein receptor (LDLR), and liver X receptor alpha (LXRα). The immunofluorescence study revealed that R and Q increased the LDLR expression, while only Q improved LDL-C uptake in HepG2 cells. Results from hypercholesterolemia hamsters fed diets containing R (5.5 g/kg diet) and Q (2.5 g/kg diet) for 8 weeks demonstrate that both R and Q had no effect on plasma total cholesterol. In the liver, only Q reduced cholesterol significantly. The discrepancy between the in vitro and in vivo studies was probably due to a poor bioavailability of flavonoids in the intestine. It was therefore concluded that R and Q were effective in reducing cholesterol in HepG2 cells in vitro, whereas in vivo, the oral administration of the two flavonoids had little effect on plasma cholesterol in hamsters.     

An insight into the electrocatalytic properties of porous La0.3Sr0.7Fe0.7Cr0.3O3−δ electrodes towards oxygen reduction reaction

Journal of Solid State Electrochemistry - The electrocatalytic properties of porous La0.3Sr0.7Fe0.7Cr0.3O3−δ electrodes towards oxygen reduction reaction were investigated as a function...     

Reduction of Dimerization Tendency Due to the Decrease in Hybridization Index by Inclusion of 4s and 4p Semicore States as Valence States in Mon (n=2-18) Clusters: A First-Principles Study

Owing to the unique structural, electronic, and physico-chemical properties, molybdenum clusters are expected to play an important role in future nanotechnologies. However, their ground states are still under debate. In this study, the crystal structure analysis by particle swarm optimization (CALYPSO) approach is used for the global minimum search, which is followed by first-principles calculations, to detect an obvious dimerization tendency in Mo\begin{document}$ _n $\end{document} (\begin{document}$ n $\end{document} = 2\begin{document}$ - $\end{document}18) clusters when the 4s and 4p semicore states are not regarded as the valence states. Further, the clusters with even number of atoms are usually magic clusters with high stability. However, after including the 4s and 4p electrons as valence electrons, the dimerization tendency exhibits a drastic reduction because the average hybridization indices \begin{document}$ H_{ \rm{sp}} $\end{document}, \begin{document}$ H_{ \rm{sd}} $\end{document}, and \begin{document}$ H_{ \rm{pd}} $\end{document} are reduced significantly. Overall, this work reports new ground states of Mo\begin{document}$ _n $\end{document} (\begin{document}$ n $\end{document} = 11, 14, 15) clusters and proves that semicore states are essential for Mo\begin{document}$ _n $\end{document}     

Rapid Preparation of Mesoporous Methylsilsesquioxane Aerogels by Microwave Heating Technology

Microwave heating technology is known as an alternative to traditional gas and electric heating sources. In this work, mesoporous methylsilsesquioxane (MSQ) aerogels were prepared via a sol–gel process accompanied by microwave heating technology, and microwave heating was used in the gelation of sol and the drying of wet gels, respectively. The effects of hexadecyltrimethylammonium chloride (CTAC) as a surfactant and template, hydrochloric acid (HCl) as a catalyst, ethanol as a solvent, sodium hydroxide (NaOH) as a gelation agent, and microwave power on the pore structure of as-prepared MSQ aerogels were investigated in detail. Microwave heating at low power results in the acceleration of sol–gel transition and achieves the gelation within a few minutes. Appropriate amounts of chemical reagents and microwave heating at high power allow the preparation of mesoporous MSQ aerogels with a BET-specific surface area of 681.6 m²·g⁻¹ and a mesopore size of 19 nm, and the resultant MSQ aerogel still has a BET specific surface area as high as 134 m²·g⁻¹ after heat treatment at 600 °C for 2 h, showing high thermal stability. The MSQ aerogels/fibre composite possesses a low thermal conductivity of 0.039 W/(m·k)⁻¹, displaying good thermal insulation. Microwave heating technology is a promising heating method for the preparation of other aerogels.     

Thermal behaviors and kinetic analysis of two natural kaolinite samples selected from Qingshuihe region in Inner Mongolia in China

Journal of Thermal Analysis and Calorimetry - The thermal characteristic behaviors of two kaolinite samples selected from Qingshuihe region in Inner Mongolia in China were studied through...     

Study on backward-facing step flow and heat transfer characteristics of hybrid nanofluids

Journal of Thermal Analysis and Calorimetry - As high heat dissipation has increasingly become the primary factor restricting the capability of electronic elements, and the high temperature of the...     

基于多肽识别的电化学生物传感技术

多肽具有分子量小、易于合成、生物兼容性好、稳定性高及序列灵活多样等优点。因此,多肽作为新型生物识别元件,已被广泛应用于生物传感器的构建。电化学分析灵敏度高、准确度好、设备简单、检测范围广且易于操作。本文介绍了基于多肽识别的电化学生物传感器技术,包括多肽的修饰与固定化、多肽与待测物的识别及检测原理;综述了近五年多肽电化学生物传感器对重金属离子、小分子、蛋白质、细菌和病毒的检测;展望了肽基电化学生物传感器的发展趋势。