نتایج جستجو برای: polar compounds
تعداد نتایج: 268855 فیلتر نتایج به سال:
A comprehensive analytical method for nearly 1000 semi-volatile organic compounds (SVOC) in sediments has been developed using an automated identification and quantification system with a GC-MS database. The results of recovery tests using model compounds, which comprise of 119 non-polar to polar compounds, showed that the method can quantitatively analyze most SVOC, except for very polar subs...
Hybrid polar compounds, of which hexamethylenebisacetamide (HMBA) is the prototype, are potent inducers of differentiation of murine erythroleukemia (MEL) cells and a wide variety of other transformed cells. HMBA has been shown to induce differentiation of neoplastic cells in patients, but is not an adequate therapeutic agent because of dose-limiting toxicity. We report on a group of three pote...
The fields of metabolomics and metabonomics attempt to phenotype and quantify the vast array of metabolites present in biological samples. Reversed-phase liquid chromatography (LC) coupled with mass spectrometry (MS) is a valuable tool in the separation and identification of these compounds. Reversed-phase HPLC techniques cover a wide range of compounds. However, ionic and polar compounds such ...
Cyclodextrins (CDs) are a family of cyclic oligosaccharides which are composed of α (1,4) -linked glucopyranose subunits. Thebest-characterized forms are α, β and γ CD which are consisted of six, seven and eight D-glucose units, respectively. Cyclodextrins are produced from starch by enzymatic degradation. These macrocyclic carbohydrates with polar internal cavities can form complexes with and ...
اسانس گیاهان (خشک شده در سایه)، tanacetum tenuisectum , tanacetum polycephalum به دو روش: 1- تقطیر با آب 2- برای اولین بار به روش میکرواستخراج فاز جامد در فضای فوقانی گرفته شد و به روش gc/ms مورد آنالیز و شناسایی واقع گردید. عمده ترکیبات اسانس سرشاخه های گلدار گیاه (tanacetum polycephalum) hydrodistillation % compounds 12.07 camphor 10.66 1, 8- cineole 9.57 chrysanthenyl acetate – t...
BACKGROUND Ginsenosides, the major ingredients of Panax ginseng, have been studied for many decades in Asian countries as a result of their wide range of pharmacological properties. The less polar ginsenosides, with one or two sugar residues, are not present in nature and are produced during manufacturing processes by methods such as heating, steaming, acid hydrolysis, and enzyme reactions. (1)...
Influence of some lysosomotropic compounds on calcium ion desorption process from liposome membrane.
The effect of a group of model lysosomotropic compounds on the process of Ca2+ ion desorption from lecithin liposome membranes was studied. The compounds studied were: hydrochlorides of fatty acids 2-dimethylaminoethyl esters (DM-n) for n = 9, 11, 13 and 15 carbon atoms in the fatty acid alkyl chain and methochloride of 2-dimethylaminoethyl laurate (DMS-11). It was found that all the compounds ...
Interest in the health-promoting effects of virgin olive oil, an important part of the "Mediterranean diet", prompted us to determine the antiinflammatory effects of erythrodiol, beta-sitosterol and squalene, identified as major components of the so-called "unsaponifiable fraction" of virgin olive oil, as well as of the phenolic compounds from the "polar fraction": oleuropein, tyrosol, hydroxyt...
BACKGROUND Calculating Abraham descriptors from solubility values requires that the solute have the same form when dissolved in all solvents. However, carboxylic acids can form dimers when dissolved in non-polar solvents. For such compounds Abraham descriptors can be calculated for both the monomeric and dimeric forms by treating the polar and non-polar systems separately. We illustrate the met...
Plant cuticles have been reported as highly efficient sorbents for organic compounds. The objective of this study was to elucidate the sorption and desorption behavior of polar and nonpolar organic compounds with the major structural components of the plant cuticle: the biopolymers cutin and cutan. The sorption affinity values of the studied compounds followed the order: phenanthrene > atrazine...
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