نتایج جستجو برای: organic solvents
تعداد نتایج: 235734 فیلتر نتایج به سال:
BACKGROUND Noise exposure is a well-known contributor to work-related hearing loss. Recent biological evidence suggests that exposure to ototoxic chemicals such as organic solvents and heavy metals may be additional contributors to hearing loss. However, in industrial settings, it is difficult to determine the risks of hearing loss due to these chemicals in workplaces accompanied by excessive n...
introduction: hearing loss is one of the most common occupational diseases. in most workplaces, workers are exposed to noise and solvents simultaneously, so the potential risk of hearing loss due to solvents may be attributed to noise. in this study we aimed to assess the effect of exposure to mixed aromatic solvents on hearing in the absence of exposure to hazardous noise. materials and met...
In this communication, we report a physical method for the fabrication of organic solvent and surfactant-resistant barriers on paper-based fluidic devices. When nonwoven polypropylene sheet is embossed with a steel mold, the embossed region acts as a physical barrier that can prevent the flow of liquids. Embossed polypropylene barriers not only block water, but also block organic solvents and s...
The elevated nitric oxide/peroxynitrite and the neural sensitization theories of multiple chemical sensitivity (MCS) are extended here to propose a central mechanism for the exquisite sensitivity to organic solvents apparently induced by previous chemical exposure in MCS. This mechanism is centered on the activation of N-methyl-D-aspartate (NMDA) receptors by organic solvents producing elevated...
Water-miscible organic co-solvents can be used in DNA-based catalytic asymmetric reactions at appreciable concentration without a negative effect on enantioselectivity. While the rate of the copper(II) Diels-Alder reaction is affected negatively by the presence of organic co-solvents, the copper(II) catalyzed Michael addition and Friedel-Crafts alkylation reaction are significantly faster. Addi...
Three different lipases (porcine pancreatic, yeast, and mold) can vigorously act as catalysts in a number of nearly anhydrous organic solvents. Various transesterification reactions catalyzed by porcine pancreatic lipase in hexane obey Michaelis-Menten kinetics. The dependence of the catalytic activity of the enzyme in organic media on the pH of the aqueous solution from which it was recovered ...
isotactic poly (1-butene), ipbu-1, was synthesized by using a metallocene catalyst. the thermodynamic phase behavior of polymer–organic solvents systems is very important in every polymer application. in this paper, the solid–liquid equilibrium of ipbu-1 with different organic solvents (1-heptyne, cyclo octane) was studied by a mathematical model. by considering the experiments temperature-mol...
ethylammonium propionate with high polarity and ionic conductivity was synthesized andcharacterized with 1hnmr and ir. this ionic liquid which is prepared from readily available startingmaterial in high yield shows reasonably high at viscosity and heat stability up to 150 °c. this ionicliquid is able to dissolve most of organic solvents due to the hydrogen interaction between ionicliquid and th...
A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temper...
Volatile organic compounds (VOCs) have been found to be a major contributor to air pollution in many chemical and industrial processes. Recently, a new class of solvents–ionic liquids, which are chemically stable and non-volatile liquid organic salts at temperatures less than 100 C, have attracted widespread interest due to its negligible volatility, nonflammability and high ionic conductivity....
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