Partially biobased polyamphiphile-bearing reactive epoxy groups in the side chains and its application to the hydrogel

Partially biobased polyamphiphile-bearing reactive epoxy groups in the side chains were obtained in 62–78 % yields by a radical copolymerization of limonene oxide (LO) and PEG methylacrylate (PEGA) with different feed ratios. Degree of LO incorporation into the copolymer was determined as 12–23 % by ¹H NMR spectroscopic analysis. The copolymer having LO unit:PEGA unit = 19:81 formed polymer associates in water, particle diameter of which was ranged mainly from 4 to 66 nm and hydrodynamic mean diameter was 12.3 nm. Its critical micelle concentration was determined as 0.53 g/L by fluorescence spectroscopic analysis. A cross-linking reaction of the epoxy groups in the side chains was conducted with 3.97 mol% (to the epoxy group) of branched poly(ethylene imine) as a cross-linker to give the corresponding hydrogel in 56 % yield. The hydrogel can absorb water as much as 13 times its own mass.     

Water permeation properties of SiO2-RSiO3/2 (R = methyl,vinyl, phenyl) thin films prepared by the sol-gel method on nylon-6 substrate

Nylon-6 substrates were coated with SiO₂-RSiO_3/2 (R = methyl, vinyl, phenyl) thin films by the sol-gel method, and their water permeability was evaluated Tetraethoxysilane (TEOS) and trifunctional alkoxides such as methyltriethoxysilane (MTES), vinyltriethoxysilane (VTES), and phenyltriethoxysilane (PhTES) were used as starting materials. Water permeability coefficients of the nylon-6 substrates coated with these SiO₂-RSiO_3/2 thin films were increased with an increase in the content of these trialkoxysilanes in the films. The water permeability coefficients of these coated nylon-6 substrates were smaller in the order of the systems TEOS-PhTES < TEOS-VTES < TEOS-MTES in the relatively low content of the trialkoxysilanes. © 1996 John Wiley & Sons, Inc.     

Deoxidation of Ti Melt by Newly Developed Two-Step Plasma Arc Melting Process Using Hydrogen

Metallurgical and Materials Transactions B - A two-step plasma arc melting process, comprising a first step under Ar-30&nbsp;pct H2 gas flow and the second step under Ar gas flow, has been...     

Polyphasic characterization of two microbial consortia with wide dechlorination spectra for chlorophenols

Two soil-free anaerobic dechlorinating cultures (3-CP and 35-DCP) were enriched from a pentachlorophenol (PCP)-to-phenol dechlorinating soil-dependent culture, using 3-chlorophenol (3-CP) and 3,5-dichlorophenol (3,5-DCP) as specific respective substrates, and characterized polyphasically. Physiological characterization indicated that the 3-CP and 35-DCP cultures had similar features, but with some variations. Both cultures utilized formate or acetate preferably as optimum electron donors for reductive dechlorination, and they shared similar patterns of dechlorination spectra for chlorophenols ranging from mono-CPs to a tetra-CP, with preferred dechlorination pathways in the ortho and meta positions. Alternative electron acceptors such as NO(3)(-) but not SO(4)(2-) inhibited the dechlorination activity in both cultures, while amorphous iron oxides (FeOOH) suppressed dechlorination activity only in the 35-DCP culture. Complete inhibition of dechlorination was observed in both cultures supplemented with chloramphenicol and vancomycin. The addition of 2-bromoethanesulfonate resulted in delayed dechlorination activity in the 35-DCP culture but not in the 3-CP culture; molybdate did not exert any inhibitory effect in either culture. Phylogenetic analysis based on 16S rRNA genes confirmed that the two cultures exhibited similar bacterial species but with varied responsible dechlorinators. Dehalobacter spp. were the likely dechlorinators in the 3-CP culture versus Sulfurospirillum spp. in the 35-DCP culture, with Clostridium and Clostridium-like spp. as candidate dechlorinators in both cultures.     

Speciation of selenium in selenium-enriched seeds,buckwheat (<Emphasis Type="Italic">Fagopyrum esculentum</Emphasis> Moench) and quinoa (<Emphasis Type="Italic">Chenopodium quinoa</Emphasis> Willdenow)

Buckwheat (Fagopyrum esculentum Moench) and quinoa (Chenopodium quinoa Willdenow) are widely used as food ingredients. The nutritional characteristics of these plants, i.e., high contents of proteins and amino acids suggest that selenium (Se) is preserved as selenoamino acid derivatives, in particular, selenomethionine (SeMet) in proteins, similar to selenized yeast. Therefore, buckwheat and quinoa are expected to be a good nutritional source of Se. Selenized buckwheat and quinoa were cultivated on Se-fortified soil using sparingly soluble Se salts, such as barium selenate and barium selenite. Se concentration in the edible parts of these plants was determined, and Se extraction efficiency with enzyme or alkali was evaluated. In addition, the chemical species of Se in the low molecular weight fraction of these plants were determined by HPLC-ICP-MS. Total Se concentrations in the edible parts of selenized buckwheat and quinoa were 170.4 ± 2.9 μg/g and 102.7 ± 2.4 μg/g wet weight, respectively. Thus, these selenized seeds were found to be Se accumulators. The results indicate that Se in selenized buckwheat exists mainly as SeMet, while Se in selenized quinoa exists not only as SeMet but also as selenate (Se(VI)) and non-protein forms.     

Multiresidue method for pesticides and veterinary drugs in bovine milk using GC/MS and LC/MS/MS

A simple, sensitive and selective method with gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) has been developed to detect 342 pesticides and veterinary drugs contaminating bovine milk at the maximum residue limits (MRLs) defined in the "positive list system". Sample preparation was performed by extracting the analytes with acetonitrile, followed by salting-out with sodium chloride. For some pesticides, the extract was further cleaned up by n-hexane partitioning and PSA cartridge column chromatography. GC/MS-EI or -NCI was used to determine pesticide residues, while LC/MS/MS-ESI was applicable to the determination of pesticide and veterinary drug residues. The variation of the recoveries of these drugs at MRL was relatively wide; however the relative standard deviations of the recovery of each drug were within 28%, suggesting that the present method is good enough for use as a screening test for contaminants at the MRLs. These results show that this method is useful for multiresidue analysis of numerous pesticides and veterinary drugs in bovine milk.     

Investigation of the Aroma Profile of Green Tea Leaves Using Organic Synthesis and Conventional Analytical Techniques

Although many aroma components have been identified in green tea leaves, the aroma compounds contributing to green tea＇s characteristic odor have not yet been reported. The authors recently reported that aroma components with a matcha-like odor are present in both green tea and black tea prepared from the Sayamakaori tea cuttivar. This matcha-like odor is similar to the odor of commercial available matcha （high-quality powdered green tea）, and is a specific odor feature of green tea leaves. At present, the green-tea odor is thought to arise from the combination of a large number of constituents. Recent reports indicate that a complex interaction between olfactory receptors and odorants is important for the evaluation of the odors. Taking into consideration these findings, the authors investigated the aroma profile of green tea, focusing on the characteristic molecular structures of the constituents that give matcha-like odor. Using a combination of organic synthesis and gas chromatography-mass spectrometry plus gas chromatography-olfactometry, the authors identified aroma components with matcha-like odors in five other tea cultivars. This investigation also revealed that several compounds with a formyl group were important constituents of the aroma of green tea leaves, although the odor of each constituent was not individually similar to the tea＇s overall aroma. The authors found for the first time a group of key components that have the matcha-like odor.     

Enzymatic Synthesis of 1‐Alkyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate Using a Novel Lysoplasmalogen‐Specific Phopholipase D

Many phospholipase Ds (PLDs) are known to catalyze transphosphatidylation as well as hydrolysis of phospholipids. Transphosphatidylation of lysoplasmalogen (LyPls)‐specific phospholipase D (LyPls‐PLD), which catalyzes hydrolysis of ether lysophospholipids such as LyPls and 1‐hexadecyl‐2‐hydroxy‐sn‐glycero‐3‐phosphocholine (Lyso‐PAF), still remains unclear. This study aims to reveal the transphosphatidylation activity of LyPls‐PLD, that is, the production of cyclic ether lysophospholipid. The enzymatic reaction is conducted in a buffer system, and the reaction products of a novel LyPls‐PLD from Thermocrispum sp. are investigated using mass spectrometry (MS). MS analyses demonstrate the reaction products to consist of 100% 1‐hexadecyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate (cLyPA) and choline from Lyso‐PAF; however, 1‐alkenyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate from 1‐O‐1′‐(Z)‐octadecenyl‐2‐hydroxy‐sn‐glycero‐3‐phosphocholine and 1‐O‐1′‐(Z)‐octadecenyl‐2‐hydroxy‐sn‐glycero‐3‐phosphoethanolamine is not produced. These results are expected to help in elucidating the catalytic mechanism of LyPls‐PLD, that is, the rate‐limiting step, and indicate LyPls‐PLD to be useful for the one‐pot synthesis of cLyPA. Practical Applications: A novel phospholipase D, LyPls‐PLD, can exclusively synthesize cLyPA from Lyso‐PAF using a one‐step enzymatic reaction without an organic solvent. cLyPA could be expected to show bioactivities similar to those of cyclic phosphatidic acid, which promotes normal cell differentiation, hyaluronic acid synthesis, antiproliferative activity in fibroblasts, and inhibitory activity toward cancer cell invasion and metastasis.