Contribution of glycation to human lens coloration

To study the contribution of glycation or the Maillard reaction to the spontaneous coloration of human crystalline lens in aging, we determined 1-deoxyfructosyl adduct and the fluorescent material, which are produced in the early stage of glycation, in the proteins of normal and colored human lenses of different ages. The amount of both glycation products in the lens increased significantly in proportion to aging or the advance of lens coloration. The insolubility of lens protein also increased with the advance of glycation. In addition, the present study showed that glucose and glucose-6-phosphate have higher reactivities with human lens protein than fructose and glucose-1-phosphate. This paper demonstrates that the deeper colored or older aged lens contains larger amounts of glycation products, and that glycation between lens protein and various sugars in vivo may be a serious factor in human lens coloration or insolubilization of lens protein.     

Reaction of 2,5-diisopropyl- and 2,5-di-sec-butylpyrazine 1-oxide. Derivatives with phosphoryl chloride and acetic anhydride

In order to examine the α-substitution of side chains, various derivatives of 2,5-diisopropyl- and 2,5-disec-butylpyrazine 1-oxides were subjected to the reaction with phosphoryl chloride and acetic anhydride. Chlorination and acetoxylation were recognized to take place on the pyrazine ring in almost all cases.     

Study of photoanode kinetics at metal-free phthalocyanine in an organic p/n bilayer with respect to the pH conditions employed

Using an organic p/n bilayer comprised of 3,4,9,10-perylenetetracarboxyl-bisbenzimidazole (PTCBI, an n-type semiconductor) and 29H,31H-phthalocyanine (H₂Pc, a p-type semiconductor) as a photoanode in the presence of Fe^II(CN)₆^4? (an electron donor), the oxidation kinetics on the H₂Pc surface was investigated with respect to the pHs employed (i.e. pH = 4, 7, and 10). The kinetic analysis of the rate-limiting charge transfer between H₂Pc and Fe^II(CN)₆^4? was conducted by assuming the Langmuir adsorption equilibrium at the H₂Pc/water interface. In addition to a demonstration of the PTCBI/H₂Pc photoanode under the weakly acidic–alkaline conditions, the present work evidently shows that the photoanodic reaction is kinetically independent of the pH conditions employed.     

Ethylene–propylene copolymerization behavior of ansa‐dimethylsilylene(fluorenyl)(amido)dimethyltitanium complex: Application to ethylene–propylene–diene or ethylene–propylene–norbornene terpolymers

Copolymerization behavior of ethylene (E) and propylene (P) using ansa‐dimethylsilylene(fluorenyl)(amido)dimethyltitanium complex was investigated. P was more reactive than E regardless of the chain‐end monomer unit, which was very unusual in the coordination polymerization system. The terpolymerizations of E, P and norbornene (NB) or 5‐ethylidene‐2‐norbornene (5E2N) were also performed. The each content in the E/P/NB terpolymer was independently controlled by the initial concentration of NB and E/P feed ratio. Glass transition temperature (T_g) of the terpolymer was raised in proportion to the NB content and close to that of the corresponding NB/E random copolymer with the same NB content. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 685–691     

Scandium triflate-catalyzed 6,6′-diiodination of 2,2′-dimethoxy-1,1′-binaphthyl with 1,3-diiodo-5,5-dimethylhydantoin

Scandium triflate-catalyzed iodination of 2,2′-dimethoxy-1,1′-binaphthyl with 2 equiv of 1,3-diiodo-5,5-dimethylhydantoin (DIH) proceeded to give 6,6′-diiodo-2,2′-dimethoxy-1,1′-binaphtyl in 98% yield and subsequent deprotection of methyl groups provided 6,6′-diiodo-1,1′-binaphthol, which is a useful ligand or reagent for many enantioselective transformations. Use of 2 equiv of NIS in place of DIH in the presence of scandium triflate, however, did not successfully yield 6,6′-diiodo-2,2′-dimethoxy-1,1′-binaphtyl, indicating that one of two types of iodine atoms in DIH is more reactive toward the iodination than iodine in NIS.     

Enhancing the lateral-flow immunoassay for viral detection using an aqueous two-phase micellar system

Availability of a rapid, accurate, and reliable point-of-care (POC) device for detection of infectious agents and pandemic pathogens, such as swine-origin influenza A (H1N1) virus, is crucial for effective patient management and outbreak prevention. Due to its ease of use, rapid processing, and minimal power and laboratory equipment requirements, the lateral-flow (immuno)assay (LFA) has gained much attention in recent years as a possible solution. However, since the sensitivity of LFA has been shown to be inferior to that of the gold standards of pathogen detection, namely cell culture and real-time PCR, LFA remains an ineffective POC assay for preventing pandemic outbreaks. A practical solution for increasing the sensitivity of LFA is to concentrate the target agent in a solution prior to the detection step. In this study, an aqueous two-phase micellar system comprised of the nonionic surfactant Triton X-114 was investigated for concentrating a model virus, namely bacteriophage M13 (M13), prior to LFA. The volume ratio of the two coexisting micellar phases was manipulated to concentrate M13 in the top, micelle-poor phase. The concentration step effectively improved the M13 detection limit of the assay by tenfold from 5?×?10⁸ plaque forming units (pfu)/mL to 5?×?10⁷ pfu/mL. In the future, the volume ratio can be further manipulated to yield a greater concentration of a target virus and further decrease the detection limits of the LFA.

Preparation,Crystallization, and X-ray Data Collection of Archaeal Oligopeptide Permease A

Crystallography Reports - Oligopeptide permease A (OppA) plays an important role in cell nutrition, uptake of cell wall peptides, and various signaling processes. In Thermococcales, OppA is a major...     

DNA hole transport on an electrode: application to effective photoelectrochemical SNP typing

A useful feature of DNA is that long-range hole transport through DNA is readily achieved. Photostimulated long-range hole transport through DNA has prospective use in the development of a conceptually new electrochemical single-nucleotide polymorphism (SNP) typing method for use as a versatile platform for gene diagnostics and pharmacogenetics. We have applied artificial DNAs designed for photostimulated long-range hole transport through DNA to SNP typing. By hybridizing photosensitizer-equipped DNA probes, immobilized on gold working electrodes, with a target DNA strand containing an SNP site, we observed a cathodic photocurrent, which markedly changed depending on the nature of the base at the specific site. The use of a combination of hole-transporting bases constitutes a very powerful method for a single-step electrochemical assay applicable to SNP typing of all types of sequences.     

Sulfation of Polysaccharides using Monomethyl Sulfate

ABSTRACT

The polysaccharides, curdlan, starch and dextran were sulfated when heated in DMSO with sodium methyl sulfate and a catalytic amount of H₂SO₄ or with pyridinium methyl sulfate. Use of diminished pressure and anhydrous CaSO₄ as a desiccant improved the degree of sulfation and recovery. Under conditions using sodium methyl sulfate, H₂SO₄ and CaSO₄ in vacuo, sulfation at O-6 was predominant in the cases of curdlan and starch, while sulfation at O-2 and O-3 was preferential in the case of dextran.