Withaferin A (WA), a withanolide purified from Withania somnifera, has been known to exert anti-inflammatory effects. The present study sought to determine the effects of WA on Helicobacter (H.) pylori-mediated inflammation in the AGS gastric epithelial cell line. Cellular production of interleukin (IL)-8 and vascular endothelial growth factor (VEGF) was measured by ELISA. Western blot analysis was performed to determine the activation of nuclear factor (NF)-κB and mitogen-activated protein kinases (MAPKs) as well as hypoxia-inducible factor 1α stabilization. Bacterial growth was also examined by measuring the optical density. Pre-treatment or co-treatment with WA efficiently reduced IL-8 production by AGS cells in response to H. pylori infection. H. pylori-induced activation of NF-κB, but not MAPKs, was also inhibited by pre-treatment of WA in the cells. However, WA did not affect VEGF production and HIF-1α stabilization induced by H. pylori in AGS cells. In addition, WA did not influence the growth of H. pylori, suggesting that the anti-inflammatory effect of WA was not due to any bactericidal effect. These findings indicate that WA is a potential preventive or therapeutic agent for H. pylori-mediated gastric inflammation.
a Adsorption/interaction of Carbon monoxide (CO) on a catalytic surface is the key step in electrochemical conversion of CO2 for environmental consideration. Copper (Cu) is known to be the most efficient catalyst for this purpose. Thus, this paper investigates effects of CO adsorption on the electronic/atomic state of polycrystalline Cu surface by using x-ray absorption spectroscopy (XAS). X-ray absorption near-edge structure (XANES) tells that the Cu K-edge shift +0.2 eV on adsorbing CO. Extended x-ray absorption fine structure (EXAFS) analysis informs that CO adsorption disturbs Cu surface, i.e. increase of Cu-Cu bonding distance and decrease of the coordination number of the first nearest neighbor. Both the results of XANES and EXAFS imply decrease of d-electron density of Cu on the adsorption. Demonstrated is that XAS is very useful in studying the surface phenomena of a catalyst but requires further efforts.
Membrane fouling is a major problem that hinders the application of the membrane in water filtration. To address this issue, a novel reversed thermally induced phase separation (RTIPS) process is applied to fabricate a patterned polyethersulfone (PES) hollow fiber (HF) membrane using a structured spinneret. Surface patterning could induce turbulence, thereby preventing the accumulation of foulants on membrane surface. The RTIPS method requires lesser material with similar mechanical strength compared to that of conventional TIPS method. The fabrication process is optimized by changing the spinning conditions. A dope composition of 24 wt% PES is chosen to prepare the membrane. The chemical composition of the membrane is confirmed via sophisticated techniques such as Fourier‐transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) images of the sample indicates the successful formation of the pattern on the shell side of the HFs. The prepared patterned HF membranes exhibits a high rejection of 97% of bovine serum albumin (BSA), which is comparable to or higher than that of commercial membranes. Moreover, the patterned membrane demonstrates better performance, thereby confirming the effectiveness of this modification in enhancing the antifouling nature.
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