The stability of monochlorotriazinyl reactive dyes on cellulose films in aqueous alkaline solutions containing peroxide bleaching agents

The stability of seven reactive (one difluoromonochloropyrimidinyl and six monochlorotriazinyl) dyes on cellulose immersed in sodium peroxoborate (PB) solution (UK–TO solution) containing tetraacetylethylenediamine (TAED) was examined using cellulosic films at 60 °C. The extent of dye loss that occurred from the dyed cellulosic films which were immersed in the UK–TO solution without detergent correlated closely to the ratings obtained using the BS 1006 UK–TO wash test. The dye loss that occurred from the dyed cellophane films was attributed to three contributions, namely, alkaline hydrolysis of dye–fibre bonds, oxidative fading of the dye chromophore by peroxides and cellulose degradation accelerated by PB and TAED. The alkaline hydrolysis of the dye–fibre bond and the extent of cellulose degradation in the UK–TO solution were the main contributions to the dye loss; dye oxidation was a minor factor in the dye loss mechanism. The physical bonding of the dye molecules reinforced the covalent dye–fibre bond stability towards the UK–TO solution.     

Oxidation of Low-Oxygen Silicon Carbide Fibers (Hi-Nicalon) in Carbon Dioxide

Polycarbosilane-derived low-oxygen SiC fibers, Hi-Nicalon, were heat-treated for 36 ks at temperatures from 1273 to 1773 K in CO₂ gas. The oxidation of the fibers was investigated through the examination of mass change, crystal phase, resistivity, morphology, and tensile strength. The mass gain, growth of β-SiC crystallites, reduction of resistivity of the fiber core, and formation of protective SiO₂ film were observed for the fibers after heat treatment in CO₂ gas. SiO₂ film crystallized into cristobalite above 1573 K. Despite the low oxygen potential of CO₂ gas ( p _O2= 1.22 Pa at 1273 K − 1.78 × 10² Pa at 1773 K), Hi-Nicalon fibers were passively oxidized at a high rate. There was a large loss of tensile strength in the as-oxidized state at higher temperatures because of imperfections in the SiO₂ film. On the other hand, the fiber cores showed better strength retention even after oxidation at 1773 K.     

Field evaluation of a Portable Fine Particle Concentrator (PFPC) for ice nucleating particle measurements

The custom-built Portable Fine Particle Concentrator (PFPC) is evaluated for the measurement of ice nucleating particles (INPs) in the atmosphere. The concentrations of INPs in remote regions of the atmosphere are very low, often close to instrumental detection limits. The PFPC is a dual slit-nozzle virtual impactor where particles are concentrated from an input flow of 250 LPM (litres per minute) into an output flow of 10 LPM. The enrichment factors (EFs) for ambient particles with diameters between 0.4 and 2.5?µm were found to be 21?±?5 at sea level and 18?±?2 at a field station 3580 meters above sea level for the PFPC operated in horizontal configuration. Similar enhancement factors (16?±?5) in the concentrations of INPs measured by the Horizontal Ice Nucleation Chamber at the high-altitude station were observed when the air mass was characterized by high numbers of particles larger than 0.5?µm. When the number size distribution was dominated by particles smaller than 0.5?µm, the INP EF was considerably lower. Corroborating short-term measurements were provided by additional INP-measuring instruments, the Fast Ice Nucleus CHamber and the Frankfurt Ice Deposition Freezing Experiment. Results from two aerosol mass spectrometers also indicate significant particle enhancement using the PFPC. These results indicate that the PFPC can be usefully deployed to improve the detection efficiency of ambient INP measurements.

Copyright © 2019 American Association for Aerosol Research     

miR-29 Represses the Activities of DNA Methyltransferases and DNA Demethylases

Members of the microRNA-29 (miR-29) family directly target the DNA methyltransferases, DNMT3A and DNMT3B. Disturbances in the expression levels of miR-29 have been linked to tumorigenesis and tumor aggressiveness. Members of the miR-29 family are currently thought to repress DNA methylation and suppress tumorigenesis by protecting against de novo methylation. Here, we report that members of the miR-29 family repress the activities of DNA methyltransferases and DNA demethylases, which have opposing roles in control of DNA methylation status. Members of the miR-29 family directly inhibited DNA methyltransferases and two major factors involved in DNA demethylation, namely tet methylcytosine dioxygenase 1 (TET1) and thymine DNA glycosylase (TDG). Overexpression of miR-29 upregulated the global DNA methylation level in some cancer cells and downregulated DNA methylation in other cancer cells, suggesting that miR-29 suppresses tumorigenesis by protecting against changes in the existing DNA methylation status rather than by preventing de novo methylation of DNA.     

Cationic polymerization of hydrogenated bisphenol‐A glycidyl ether with cycloaliphatic epoxy resin and its thermal discoloration

One of the key issues associated with epoxy resin–based LED encapsulant is discoloration under operating conditions that caused a decrease in light output. In this article, thermal cationic polymerization of hydrogenated bisphenol‐A glycidyl ether using 3‐methyl‐2‐butenyltetramethylenesulfonium hexafluoroantimonate and its discoloration are reported. Polymerization was followed by thermal analysis, FT‐IR spectrum, and hardness measurements. Thermal discoloration was measured by yellowness index based on transmittance spectrum. Increased catalyst concentration causes acceleration in polymerization rates, but this also increased discoloration after thermal aging. In low catalyst concentration under 0.3 wt %, the hardness of plaque was low and required a high temperature to complete polymerization and this resulted in a highly colored plaque. Formulation with cycloaliphatic epoxy (3′‐4′‐epoxycyclohexane)methyl 3′‐4′‐epoxycyclohexyl‐carboxylate (CEL2021P) enhanced the polymerization even at low catalyst concentration and reduced thermal discoloration. With addition of di‐t‐butylphenol (BHT) as the oxidation inhibitor, the thermal discoloration was extremely improved but this also caused inhibition of polymerization as seen by thermal analysis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1395–1400, 2005     

Self-Assembling Properties and Recovery Effects on Damaged Skin Cells of Chemically Synthesized Mannosylerythritol Lipids

Mannosylerythritol lipids (MELs), which are one of the representative sugar-based biosurfactants (BSs) produced by microorganisms, have attracted much attention in various fields in the sustainable development goals (SDGs) era. However, they are inseparable mixtures with respect to the chain length of the fatty acids. In this study, self-assembling properties and structure-activity relationship (SAR) studies of recovery effects on damaged skin cells using chemically synthesized MELs were investigated. It was revealed, for the first time, that synthetic and homogeneous MELs exhibited significant self-assembling properties to form droplets or giant vesicles. In addition, a small difference in the length of the fatty acid chains of the MELs significantly affected their recovery effects on the damaged skin cells. MELs with medium or longer length alkyl chains exhibited much higher recovery effects than that of C18-ceramide NP.     

Correlations of Hepatic Hemodynamics,Liver Function,and Fibrosis Markers in Nonalcoholic Fatty Liver Disease: Comparison with Chronic Hepatitis Related to Hepatitis C Virus

The progression of chronic liver disease differs by etiology. The aim of this study was to elucidate the difference in disease progression between chronic hepatitis C (CHC) and nonalcoholic fatty liver disease (NAFLD) by means of fibrosis markers, liver function, and hepatic tissue blood flow (TBF). Xenon computed tomography (Xe-CT) was performed in 139 patients with NAFLD and 152 patients with CHC (including liver cirrhosis (LC)). The cutoff values for fibrosis markers were compared between NAFLD and CHC, and correlations between hepatic TBF and liver function tests were examined at each fibrosis stage. The cutoff values for detection of the advanced fibrosis stage were lower in NAFLD than in CHC. Although portal venous TBF (PVTBF) correlated with liver function tests, PVTBF in initial LC caused by nonalcoholic steatohepatitis (NASH-LC) was significantly lower than that in hepatitis C virus (C-LC) (p = 0.014). Conversely, the liver function tests in NASH-LC were higher than those in C-LC (p < 0.05). It is important to recognize the difference between NAFLD and CHC. We concluded that changes in hepatic blood flow occurred during the earliest stage of hepatic fibrosis in patients with NAFLD; therefore, patients with NAFLD need to be followed carefully.     

Separation of Ru(III), Rh(III) and Pd(II) from nitric acid solutions using ion-exchange resins bearing carboxylic betaine

To understand the adsorption properties of a styrene–divinylbenzene copolymer functionalized with N,N,N-trimethylglycine, AMP03, the adsorption behaviours for platinoid ions (Ru(III), Rh(III) and Pd(II)) were examined. Furthermore, we performed adsorption experiments using sample solutions by adding triethylamine, thiourea and N,N,N-trimethylglycine. Based on the adsorption data obtained in this study, we performed chromatographic experiments. The results indicated that all platinoid ions in the feed solution completely adsorbed on AMP03, and almost 80% of the adsorbed platinoid ions were recovered. These results show that AMP03 has the potential to recover Ru(III), Rh(III) and Pd(II) from high-level liquid waste.     

Hydroxy Radical,Hexanal, and Decadienal Generation by Autocatalysts in Autoxidation of Linoleate Alone and with Eleostearate

The formation of hydroxy radicals, hexanal, and 2,4-decadienal was demonstrated from the autocatalytic dimer peroxide which had been reported by us in autoxidizing linoleate (Morita and Tokita in Lipids 41:91-95, 2006). Then, autoxidizing linoleate containing eleostearate was investigated for new autocatalytic substances. The substances obtained were identified as peroxide-linked polymers consisting of both linoleate- and eleostearate-origin units with one hydroperoxy group, and also revealed activity of hydroxy-radical generation. The background of this study is as follows: the above paper reported this autocatalytic dimer peroxide as one of the real radical generators in linoleate autoxidation; this is a peroxide-linked dimer consisting of two linoleate moieties with two hydroperoxy groups, and was much more important than the main-product hydroperoxide in autocatalytic radical supply; its proposed decomposition mechanism has suggested the generation of hydroxy radicals, hexanal, and 2,4-decadienal; on the other hand, analogy to the formation mechanism of this dimer peroxide has predicted the formation of similar polymeric products from conjugated polyene components in lipids. In this study, these two predictions were successfully verified and a discussion is presented in connection with them.     

Identification of Ustilago cynodontis as a new producer of glycolipid biosurfactants, mannosylerythritol lipids, based on ribosomal DNA sequences

Mannosylerythritol lipids (MELs) are one of the most promising glycolipid biosurfactants known because of their multifunctionality and biocompatibility. The search for novel producers of MELs was undertaken based on the analysis of ribosomal DNA sequences on basidiomycetous yeasts. The bermuda grass smut fungus Ustilago cynodontis NBRC 7530, which taxonomically relates to Pseudozyma shanxiensis known as a MEL-C producer, was found to accumulate glycolipids in the cultured medium. Under a shake flask culture with soybean oil, the amount of the glycolipids was 1.4 g/L for 7 days at 25 degrees C. As a result of the structural characterization, the main glycolipids was identified as 4-O-[(4'-O-acetyl-3'-O-alka(e)noyl-2'-O-butanoyl)-beta-D-mannopyranosyl]-D-erythritol, and the major fatty acids were C(14) and C(16) ones. The glycolipid was highly hydrophilic MEL-C, and very similar to those produced by P. shanxiensis. The fungi of the genus Ustilago are thus likely to be potential producers of MELs as well as the yeasts of the genus Pseudozyma.