Neuroprotective effect of peroxiredoxin 6 against hypoxia-induced retinal ganglion cell damage

Background  

The ability to respond to changes in the extra-intracellular environment is prerequisite for cell survival. Cellular responses to the environment include elevating defense systems, such as the antioxidant defense system. Hypoxia-evoked reactive oxygen species (ROS)-driven oxidative stress is an underlying mechanism of retinal ganglion cell (RGC) death that leads to blinding disorders. The protein peroxiredoxin 6 (PRDX6) plays a pleiotropic role in negatively regulating death signaling in response to stressors, and thereby stabilizes cellular homeostasis.     

Validation of an ultra‐performance liquid chromatography–tandem mass spectrometry method for the determination of flecainide in human plasma and its clinical application

A simple and reproducible bioanalytical method for the determination of flecainide in human plasma was developed and validated using an ultra‐performance liquid chromatography with tandem mass spectrometry (UPLC‐MS/MS) to obtain higher sensitivity than the current available methods. After simple protein precipitation, flecainide and a stable isotope‐labeled internal standard (IS) were chromatographed on an Acquity UPLC BEH C₁₈ column (2.1 × 100 mm, 1.7 µm) with isocratic elution of mobile phase consisting of 45% methanol containing 0.1% formic acid at a flow rate 0.25 mL/min. Detection was performed in positive electrospray ionization by monitoring the selected ion transitions at m/z 415.4/301.1 for flecainide and m/z 419.4/305.1 for the IS. The method was validated according to current bioanalytical method validation guidelines. The calibration standard curve was linear from 2.5 to 1000 ng/mL using 0.1 mL of plasma. No significant interferences were detected in blank human plasma. Accuracy and precision in the intra‐ and inter‐batch reproducibility study were within acceptance criteria. Neither hemolysis effects nor matrix effects were observed. The UPLC‐MS/MS method developed was successfully applied to determine plasma flecainide concentrations to support clinical studies and incurred sample reanalysis also ensured the reproducibility of the method. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis of poly[2-(perfluorooctyl)ethyl acrylate-<Emphasis Type="Italic">co</Emphasis>-poly(ethylene glycol) methacrylate] and its control of enzyme activity in supercritical carbon dioxide

Poly[2-(perfluorooctyl)ethyl acrylate-co-poly(ethylene glycol) methacrylate], P(POA-co-PEGm) was prepared as a new surfactant for scCO₂. The random copolymer was obtained by the radical polymerization of 2-(perfluorooctyl)ethyl acrylate (POA) and poly(ethylene glycol) methacrylate (PEGm) in DMF. The molar ratio of the POA and PEGm units in the copolymer was POA/PEGm = 0.972/0.028 by ¹H NMR. The molecular weight and molecular weight distribution were estimated by size exclusion chromatography to be Mn = 133,000 and Mw/Mn = 8.25, respectively. It was suggested that the copolymer formed micellar aggregates with the cores of the PEGm chains in scCO₂, based on the analyses of the copolymer in hexafluorobenzene by ¹H NMR and dynamic light scattering. The copolymer was soluble in scCO₂ and had a cloud point at a much higher pressure than the critical pressure. It was found that the copolymer solubilized CO₂-insoluble proteins such as bovine serum albumin and subtilisin Carlsberg in scCO₂. The solubility of the copolymer was not influenced by the presence of the proteins; however, the solubility decreased in the presence of a small amount of water along with the protein. The activity of the subtilisin slightly decreased when only placed in scCO₂, whereas a marked decrease in the activity was observed for the subtilisin in the presence of the copolymer in scCO₂. The subtilisin activity decreased as the CO₂ pressure increased.     

Anomalous transport processes in turbulent non-Abelian plasmas

Turbulent color fields, which can arise in the early and late stages of relativistic heavy ion collisions, may contribute significantly to the transport processes in the matter created in these collisions. We review the theory of these anomalous transport processes and discuss their possible phenomenology in the glasma and quasistationary expanding quark–gluon plasma.     

Studies on the oxidative cyclization of 3-hydroxyalkyl-1,2,4-trialkoxynaphthalenes and synthetic application for the biologically active natural compound rhinacanthone

The oxidative intramolecular cyclization of 3-hydroxyalkyl-1,2,4-trimethoxynaphthalenes was investigated. A series of 1,2-naphthoquinone fused cyclic ethers were synthesized directly from 3-hydroxyalkyl-1,2,4-trimethoxynaphthalenes by exposure to diammonium cerium (IV) nitrate. To understand the reaction mechanism, the intramolecular cyclization of 3-hydroxyalkyl-naphthoquinones that were formed as reaction intermediates was also examined. The results suggested that the reaction proceeds by a stepwise oxidation–cyclization mechanism. Using this methodology, five-step synthesis of rhinacanthone was achieved with high yield.     

Relativistic heavy ion collisions — Where are we now? Where do we go?

Various aspects of the current status of ultrarelativistic heavy ion collisions are reviewed. Perspectives of heavy ion physics in the future are given as well.     

Nitroxide-mediated photo-living radical polymerization of methyl methacrylate in the presence of (η6-benzene)(η5-cyclopentadienyl)FeII hexafluorophosphate

The photoradical polymerization of methyl methacrylate (MMA) was performed at room temperature using (2RS,2’RS)-azobis(4-methoxy-2,4-dimethylvaleronitrile) as the initiator and 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (MTEMPO) as the mediator in the presence of (η⁶-benzene)(η⁵-cyclopentadienyl)Fe^II hexafluorophosphate (BzCpFe^II). The bulk polymerization provided narrower molecular weight distributions (Mw/Mn = 1.4 − 1.5) than the solution polymerization in acetonitrile, although BzCpFe^II was insoluble in MMA. The polymerization rate was retarded by an increase in the amount of BzCpFe^II. BzCpFe^II, which had no ability to control the molecular weight by itself, could control it through the interaction with MTEMPO. The interaction of BzCpFe^II and MTEMPO was attributed to the electron transfer involving the MTEMPO–aminoxy anion redox system and the iron redox system. The polymerization was confirmed to occur in accordance with a living mechanism because linear correlations were obtained for both the plots of the first order time–conversion and the conversion–molecular weight.