In vitro and in vivo antioxidant properties of ferulic acid: A comparative study with other natural oxidation inhibitors

Ferulic acid exhibits a wide range of therapeutic effects that are attributed to its potent antioxidant capacity. However, in vitro antioxidant properties of ferulic acid have not been elucidated in detail. Evidence that polyphenols, including ferulic acid, act as antioxidants in vivo is also limited. In order to elucidate in more detail the scientific background of antioxidant activities of ferulic acid, we carried out in vitro and in vivo experiments. We focused on superoxide anion scavenging activity, xanthine oxidase inhibition activity, and chain-breaking activity. The combined antioxidant activity from radical scavenging and xanthine oxidase inhibition of ferulic acid was much weaker than that of (−)-epigallocatechin gallate (EGCG) and ascorbic acid. On the other hand, EGCG, ascorbic acid and ferulic acid exhibited chain-breaking activity and prevented ischaemia-reperfusion-associated intestinal injury. Chain-breaking activity may play a contributory role in the protective effect of ferulic acid on oxidative injury in humans and in in vivo studies.     

Effects of divalent cations on Halobacterium salinarum cell aggregation

Ca(2+) was found to be essential for initiating Halobacterium salinarum CCM 2090 cell aggregation. The floc formed from such aggregation could easily be dissociated without cellular lysis by sodium citrate. Cr(2+), Mn(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), and Zn(2+) could replace Ca(2+). However, Mg(2+), Sr(2+), Mo(2+), Cd(2+), Sn(2+), Hg(2+), and Pb(2+) induced no flocculation of cells of this halophilic archaeon. Mg(2+) acted antagonistically against Ca(2+)-induced aggregation. Such aggregation might be directly caused by the interaction of Ca(2+) and aggregation factors from 55 degrees C-treated cell extract.     

Constitutive production of aconitate isomerase by Pseudomonas sp. WU-0701 in relation to trans-aconitic acid assimilation

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Cloning and heterologous expression of a glucodextranase gene from Arthrobacter globiformis I42, and experimental evidence for the catalytic diad of the recombinant enzyme

The gene encoding a glucodextranase from Arthrobacter globiformis I42 was cloned and, subsequently, heterologously expressed in Escherichia coli. This glucodextranase gene consists of 1048 amino acid residues with a calculated molecular mass of 109,135 Da. The roles of two residues at the active site of A. globiformis I42 glucodextranase were examined by site-directed mutagenesis. Glutamic acid residues 458 and 656, which are part of the apparent catalytic residues, were found to be essential for hydrolase activity.     

Effect of Mn-Co spinel coating for Fe-Cr ferritic alloys ZMG232L and 232J3 for solid oxide fuel cell interconnects on oxidation behavior and Cr-evaporation

Metallic materials, especially Fe-Cr ferritic alloys, are promising as interconnect materials of solid oxide fuel cells (SOFCs) operated at around medium temperatures. ZMG232L is one of the developed Fe-Cr ferritic alloys for SOFC metallic interconnects.These metallic materials are usually machined or pressed into various shapes of interconnect parts, and thickness of these parts is often thin. However, the oxidation rate of thin sheet was much higher than that of thick one because Cr content decreased under oxide layer of edge part of thin sheet. Such accelerated oxidation behavior could be improved by reducing Mn, increasing Cr, and adding W in ZMG232L.It is also very important to reduce Cr-evaporation from the oxidized surface of ferritic alloys in cathode side. The aim of this study is to reduce the Cr-evaporation from oxidized alloy surface in air by coating with Mn-Co spinel oxide. In this study, oxidation behavior and Cr-evaporation of ZMG232L and improved Fe-Cr alloy, 232J3, coated with Mn-Co spinel oxide were investigated at elevated temperature in air. MnCo₂O₄ spinel coating on the pre-oxidized Fe-Cr ferritic alloy surface improved oxidation resistance and Cr-evaporation.     

Hydrolysis of cellulose fiber in the presence of 12-tungstosilicic acid

Hydrolysis of cellulose fiber in the presence of 12-tungstosilicic acid was investigated, and the acid was found to show a higher catalytic activity than did hydrochloric acid at the same concentration of acid, although the ratio of the activities of 12-tungstosilicic acid to hydrochloric acid depended on the concentration. The influence of the ionic strength on the reaction rates was examined, and it was believed that the difference in the ionic strength between 12-tungstosilicic acid and hydrochloric acid at the same concentration of acid was one of reasons for the higher catalytic activity of 12-tungstosilicic acid. From the examinations of change in degree of polymerization of the cellulose fiber with the hydrolysis and adsorption behavior of 12-tungstosilicic acid by the cellulose, fiber, it was found that 12-tungstosilicic acid, in spite of its bulky structure, easily penetrated into the amorphous region of the cellulose fiber, as does hydrochloric acid, and catalyzed the hydrolysis of glucoside bond there.     

Photoinduced grafting of acrylamide onto polyethylene film by means of two-step method

Benzophenone-coated low-density polyethylene (LDPE) was grafted with acrylic acid (AA), methacrylic acid (MA), acrylonitrile (AN), and methyl methacrylate (MMA) in an aqueous medium by photoirradiation. The first-step graft samples thus prepared with a grafting of about 50% were subjected to second-step photografting with acrylamide (AAm). On AA- and MA-grafted LDPE samples, the second-step grafting of AAm was very smooth, and a high level of grafting up to 800% was attained with ease. On the other hand, grafted LDPE samples employing hydrophobic monomers, AN and MMA, had a lower percent of grafting than those with hydrophilic monomers, AA and MA. By ESR study, a thermally stable radical was found in the first-step graft sample irradiated with light of λ > 330 nm. Mechanisms for the formation of such a radical in the first-step graft sample are proposed, and the contribution of the radical to the second-step grafting is discussed.     

The High-Resolution X-Ray Microcalorimeter Spectrometer, SXS, on Astro-H

The science and an overview of the Soft X-ray Spectrometer onboard the STRO-H mission are presented. The SXS consists of X-ray focusing mirrors and a microcalorimeter array and is developed by international collaboration lead by JAXA and NASA with European participation. The detector is a 6×6 format microcalorimeter array operated at a cryogenic temperature of 50 mK and covers a 3′×3′ field of view of the X-ray telescope of 5.6 m focal length. We expect an energy resolution better than 7 eV (FWHM, requirement) with a goal of 4 eV. The effective area of the instrument will be 225 cm² at 7 keV; by a factor of about two larger than that of the X-ray microcalorimeter on board Suzaku. One of the main scientific objectives of the SXS is to investigate turbulent and/or macroscopic motions of hot gas in clusters of galaxies.     

Fabrication of hydroxyapatite blended cyclic type polylactic acid and poly (ε-caprolactone) tissue engineering scaffold

The ultimate goal of tissue engineering serves to repair, restore damaged tissue or organ due to accident or disease. In this research, we are aimed at investigating the feasibility of processing cyclic type polylactic acid (PDLLA)/poly(ε-caprolactone) (PCL)/hydroxyapatite (HA) biomaterial into tissue engineering scaffold (TES) with variable mechanical properties, well interconnected pore architecture, and controlled hydrophilicity. For this, an in-house built bone scaffold 3D printing (BS3P) system was applied to two biomaterials, namely PDLLA-PCL and HA-PCL. These two biomaterials were produced by optimizing the robotic control system. Morphological investigation by scanning electron microscope (SEM) revealed both TES formed by new materials able to show honeycomb-like architectures, excellent fusion at the filament junctions, high uniformity, complete interconnectivity, and controlled channel characteristics of the TES. Compression tests align with the typical behavior of a porous material undergoing deformation. In vitro cell culture study and confocal laser microscopy (CLM) showed enhanced cell adhesion, proliferation, and extracellular matrix (ECM) formation. The results demonstrated the eligibility of the BS3P system to produce TES, and the suitability of the new biomaterial scaffolds in enhancing cell biocompatibility.