نتایج جستجو برای: ether
تعداد نتایج: 21758 فیلتر نتایج به سال:
Kathryn Rosica of the Chemical Manufacturers Association raised an interesting point in her letter (EHP vol. 102, p. 1006). Neither the term "glycol ethers" nor the term "ethylene glycol ethers" strictly identifies a class of chemicals whose members all share a common distinctive toxicological profile. As Rosica correctly noted, "Higher molecular weight ethylene glycol monoethers that have been...
Despite the fact that the discovery of ether-linked phospholipids occurred nearly a century ago, many unanswered questions remain concerning these unique lipids. Here, we characterize the ether-linked lipids of the nematode with HPLC-MS/MS and find that more than half of the phosphoethanolamine-containing lipids are ether-linked, a distribution similar to that found in mammalian membranes. To e...
Past studies on the toxicological effects of ethylene glycol alkyl ethers as well as the recent data on these chemicals in Japan are reviewed. Only a few researchers have participated in the study of ethylene glycol alkyl ethers in Japan. The effects of ethylene glycol alkyl ethers on testis and embryotoxic effects of ethylene glycol monomethyl ether (EGM) have been studied, as has the teratoge...
Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high amounts of ether-phosphatidylcholine and ether-phosphatidylethanolamine. Both lipids were specifically ...
This study concerns the structural change of lignin during auto-catalyzed ethanol-water pulping of aspen by 1H-NMR. The results showed that the linkages of alkyl-aryl ether of lignin, such as the α-ether linkages (α-O-4) and the β-ether linkages (β-O-4), were broken and the alkyl part formed carbenium at the Cα and Cβ of the aliphatic branch. Meanwhile, the aryl part of ether accepted one H and...
this paper investigates hollow and porous alumina nanospheres that were previously synthesized to be used for the dehydration of methanol to dimethyl ether (dme). as hollow nanostructures possess characteristics such as low density and high surface to volume ratio, their catalytic activity between hollow and porous structure is compared. for this purpose, three most important parameters (acidit...
in this research, a semi empirical approach has been suggested for calculating the activation energyof unimolecular thermal decomposition of vinyl ethers yielding saturated products. the calculationprocedure is based on the use of molecular mechanics (mm) methods. these methods which involvethe construction of the transition state for a molecule mainly consider the formation of a “hydrogenbridg...
The labour market, occupational safety and health, and work organisation are our main fields of activity. The creation and use of knowledge through learning, information and documentation are important to the Institute, as is international cooperation. The Institute is collaborating with interested parties in various development projects. The areas in which the Institute is active include: • la...
A method has been developed for the synthesis of semicrystalline poly(arylene ether ether sulfide) materials by first preparing a soluble, amorphous sulfoxide containing precursor, then rapidly reducing the sulfoxide moiety to sulfide. The sulfoxide polymers are synthesized using conventional nucleophilic aromatic substitution reactions between difluorodiphenyl sulfoxide and diphenols. Reductio...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید