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The surface charges of clean and natural organic matter (NOM)-adsorbed membrane surfaces of two different types of membranes (a UF and a NF membrane composed of the same material but having different pore sizes) were investigated. Concentrated NOM and its fractionated constituents were used as adsorbate and interacting macromolecules nearthe membrane surface. The zeta potential and the acidity of membranes were measured using electrophoresis and potentiometric titration methods, respectively, from the perspective of charge characterization, along with demonstration of ionic strength effects. The membrane surface was also characterized with attenuated total refractive Fourier transform infrared spectra to determine intrinsic functional groups and those changes before and after NOM adsorption. As a comparative study for the electrokinetic property of membrane, the zeta potentials for both examined polymeric membranes were determined by the electrophoresis and the streaming potential measurement methods as functions of ionic strength and the pH of measuring solution. Selectivity tests were performed to decide the relative importance of charge valence of cation in terms of the surface charge of membrane. It was demonstrated that divalent cations (Ca2+, Mg2+) increase zeta potentials relatively compared to monovalent cations (Na+, K+) because divalent cations have a greater potential in approaching membrane surfaces (i.e., inside the Stern layer). Thus, divalent cations can provide a greater double layer compaction and, when near the shear plane (available for both the zeta potential measurement methods), exist to a lesser extent than monovalent cations.

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Three cystein-tagged cellulases co-immobilized on AuNP and Au-MSNP for the hydrolytic degradation of cellulose. The biochemical properties, stabilities, activities and reusability of these co-immobilized systems were compared to those of mixtures of free cellulases.

Background: Oxidative stress and inflammation are known to play central roles in the development of diabetic nephropathy (DN). Febuxostat is a novel non-purine xanthine oxidase (XO)-specific inhibitor developed to treat hyperuricemia. In this study, we investigated whether febuxostat could ameliorate DN via renoprotective mechanisms such as alleviation of oxidative stress and anti-inflammatory actions. Methods: Male Sprague-Dawley rats were divided into three groups: a normal group, a diabetes group (DM group), and a febuxostat-treated diabetes group (DM+Fx group). We administered 5 mg/kg of febuxostat to experimental rats for 7 weeks and evaluated clinical and biochemical parameters and XO and xanthine dehydrogenase (XDH) activity in hepatic tissue. The degree of oxidative stress and extent of inflammation were evaluated from urine samples and renal tissue collected from each group. Results: Diabetic rats (DM and DM+Fx groups) had higher blood glucose and kidney weight relative to body weight than normal rats. Albuminuria was significantly reduced in febuxostat-treated diabetic rats compared with untreated diabetic rats. Quantitative analysis showed that hepatic XO and XDH activities were higher in the DM groups, but decreased after treatment with febuxostat. Urinary 8-OHdG concentrations and renal cortical nitrotyrosine also indicated reduced oxidative stress in the DM+Fx group relative to the DM group. The number of ED-1-stained cells in the glomerulus and tubule of diabetic renal tissue decreased in febuxostat-treated diabetic rats relative to that of non-treated diabetic rats. Diabetic rats also expressed higher transcript levels of inflammatory genes (E-selectin and VCAM-1), an inflammation-induced enzyme (COX-2), and inflammatory mediators (ED-1 and NF-κB) than control rats; expression of these genes was significantly reduced by treatment with febuxostat. Conclusions: Febuxostat prevents diabetic renal injury such as albuminuria. This renoprotective effect appears to be due to attenuation of the inflammatory and oxidative effects of diabetes-induced renal damage through inhibition of XO and XDH activities.

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