Transition Metal Ion Doping on ZIF-8 Enhances the Electrochemical CO2 Reduction Reaction.

The electrochemical reduction of CO2  to diverse value-added chemicals is a unique, environmentally friendly approach for curbing greenhouse gas emissions while addressing sluggish catalytic activity and low Faradaic efficiency (FE) of electrocatalysts. Here, zeolite-imidazolate-frameworks-8 (ZIF-8) containing various transition metal ions-Ni, Fe, and Cu-at varying concentrations upon doping are fabricated for the electrocatalytic CO2 reduction reaction (CO2 RR) to carbon monoxide (CO) without further processing. Atom coordination environments and theoretical electrocatalytic performance are scrutinized via X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations. Upon optimized Cu doping on ZIF-8, Cu0.5 Zn0.5 /ZIF-8 achieves a high partial current density of 11.57 mA cm-2 and maximum FE for CO of 88.5% at -1.0 V (versus RHE) with a stable catalytic activity over 6 h. Furthermore, the electron-rich sp2 C atom facilitates COOH* promotion after Cu doping of ZIF-8, leading to a local effect between the zinc-nitrogen (Zn-N4 ) and copper-nitrogen (Cu-N4 ) moieties. Additionally, the advanced CO2 RR pathway is illustrated from various perspectives, including the pre-H-covered state under the CO2 RR. The findings expand the pool of efficient metal-organic framework (MOF)-based CO2 RR catalysts, deeming them viable alternatives to conventional catalysts.

Anti-Inflammatory and Anti-Vascular Leakage Effects by Combination of Centella asiatica and Vitis vinifera L. Leaf Extracts.

Venous insufficiency results from several factors responsible for the progression of inflammation and oxidative damage of veins. Recently, natural extracts have been proposed for the treatment of venous insufficiency, but their efficacies have not been fully elucidated. In the present study, we evaluate the combinatorial effects on anti-inflammatory and anti-vascular leakage potential of mixed compositions containing different proportions of Centella asiatica extract (CE) and Vitis vinifera L. leaf extract (VVE) using an inflammation model of lipopolysaccharide- (LPS-) stimulated RAW264.7 cells and various vascular permeability models in mice (acetic-acid-induced peritoneal vascular model, mustard-oil-stimulated ear vascular model, and carrageenan-induced paw edema model). Pretreatment of CE and VVE in a 1 : 3 combination dose dependently inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) through downregulation of the nuclear factor-κB (NF-κB) pathway in LPS-stimulated RAW264.7 macrophages. In vascular permeability-related mouse models, pretreatment with the CE-VVE 1 : 3 combination significantly reduced the permeability of peritoneal or ear veins caused by acetic acid and mustard oil, respectively. Furthermore, pretreatment of the CE-VVE 1 : 3 combination ameliorated inflammation and edema of the hind paw caused by carrageenan injection. Thus, the combination of CE and VVE showed significant anti-inflammatory qualities and anti-vascular leakage effects. These findings indicate that an optimal combination of CE and VVE may have a more synergistic effect than that of CE or VVE alone as a putative agent against vascular incompetence.

Effect of polyvinylpyrrolidone (PVP) on palladium catalysts for direct synthesis of hydrogen peroxide from hydrogen and oxygen.

When synthesizing nanoparticles in the liquid phase, polymeric materials (mainly polyvinylpyrrolidone, PVP) are applied as capping and/or stabilizing agents. The polymer layer on the nanoparticles must likely be removed since it blocks the active sites of the catalyst and inhibits mass transfer of the reactants. However, we have found that the polymer can have a positive effect on the direct synthesis of hydrogen peroxide. By testing Pd/SiO2 catalysts with different amounts of PVP, it was revealed that an adequate amount of PVP resulted in a higher rate of hydrogen peroxide production (1001 mmolH2O2 gPd -1 h-1) than pristine Pd/SiO2 did (750 mmolH2O2 gPd -1 h-1), unlike other PVP added Pd/SiO2 catalysts containing excess PVP (less than 652 mmolH2O2 gPd -1 h-1). The effect of PVP on the catalysts was examined by transmission electron microscopy, Fourier transform infrared spectroscopy, CO chemisorption, thermogravimetric analysis, and X-ray photoelectron spectroscopy. For the catalysts containing PVP, the oxidation state of the palladium 3d shifted to high binding energy due to electron transfer from Pd to the PVP molecules. Consequently, the presence of PVP on the catalysts inhibited oxygen dissociation and decomposition of the produced hydrogen peroxide, resulting in a high selectivity and high production rate of hydrogen peroxide.

Dermatopontin in Skeletal Muscle Extracellular Matrix Regulates Myogenesis.

Dermatopontin (DPT) is an extensively distributed non-collagenous component of the extracellular matrix predominantly found in the dermis of the skin, and consequently expressed in several tissues. In this study, we explored the role of DPT in myogenesis and perceived that it enhances the cell adhesion, reduces the cell proliferation and promotes the myoblast differentiation in C2C12 cells. Our results reveal an inhibitory effect with fibronectin (FN) in myoblast differentiation. We also observed that DPT and fibromodulin (FMOD) regulate positively to each other and promote myogenic differentiation. We further predicted the 3D structure of DPT, which is as yet unknown, and validated it using state-of-the-art in silico tools. Furthermore, we explored the in-silico protein-protein interaction between DPT-FMOD, DPT-FN, and FMOD-FN, and perceived that the interaction between FMOD-FN is more robust than DPT-FMOD and DPT-FN. Taken together, our findings have determined the role of DPT at different stages of the myogenic process.

Studies on Catalytic Activity of Hydrogen Peroxide Generation according to Au Shell Thickness of Pd/Au Nanocubes.

The catalytic properties of materials are determined by their electronic structures, which are based on the arrangement of atoms. Using precise calculations, synthesis, analysis, and catalytic activity studies, we demonstrate that changing the lattice constant of a material can modify its electronic structure and therefore its catalytic activity. Pd/Au core/shell nanocubes with a thin Au shell thickness of 1 nm exhibit high H2O2 production rates due to their improved oxygen binding energy (Δ EO) and hydrogen binding energy (Δ EH), as well as their reduced activation barriers for key reactions.

Anti-Inflammatory Activity of Crude Venom Isolated from Parasitoid Wasp, Bracon hebetor Say.

Pest control in the agricultural fields, a major concern globally, is currently achieved through chemical or biological methods. Chemical methods, which leave toxic residue in the produce, are less preferred than biological methods. Venoms injected by stings of various wasps that kill the pest is considered as the examples of the biological method. Although several studies have investigated the biological control of pests through these venoms, very few studies have reported the effects of these venoms on mammalian cells. Bracon hebetor, an ectoparasitoid of the order Hymenoptera, is having a paramount importance in parasitizing various lepidopterous larvae including Plodia interpunctella also called as Indianmeal moth (IMM). Since it is biologically controlled by B. hebetor venom, therefore in our study, herein for the first time, we report the anti-inflammatory activities of the venom from B. hebetor (BHV). We developed a septic shock mice model for in vivo anti-inflammatory studies and RAW 264.7 cells for in vitro studies. Our results clearly demonstrate that BHV can dose dependently abrogate the nitric oxide (NO) production and suppress the levels of proinflammatory mediators and cytokines without posing any cytotoxicity via the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways.