Ether extraction studie

The heavy metal salts, ia contrast to the alkah metal salts, have lower melting points and are more soluble ia organic solvents, eg, methylene chloride, chloroform, tetrahydrofiiran, and benzene. They are slightly soluble ia water, alcohol, ahphatic hydrocarbons, and ethyl ether (18). Their thermal decompositions have been extensively studied by dta and tga (thermal gravimetric analysis) methods. They decompose to the metal sulfides and gaseous products, which are primarily carbonyl sulfide and carbon disulfide ia varying ratios. In some cases, the dialkyl xanthate forms. Solvent extraction studies of a large number of elements as their xanthate salts have been reported (19). 

A pioneer study of the distribution of this substance in the tissues of rats to which it had been fed was made by Laug (3). He evaporated ether extracts in Erlenmeyer flasks, so that a deposit was left over the bottom. Female houseflies were confined in the flasks, and the mortalities after 20 hours were compared to those obtained with known amounts of 7-hexachlorocyclohexane. Because most of the inner surface of the flask was untreated, the flies were out of contact with the toxicant during an unknown fraction of the exposure period. The exposure period was so long that the insects had to be fed dur-... 

Studies directly examining the metabolism of organophosphate ester hydraulic fluids in animals are limited. One study identified metabolites in ether extracts of bile obtained from rabbits given single,... 

In a way related are the complexes formed by Hg salts and multicrown dendrimers of different generations (dendrimers with a polypropylene amine interior of different volume and benzo[15]-crown-5 ether periphery), studied by extraction methods using radioactive 203Hg2+.210 Up to 12 Hg2+ ions were found to be bound per dendrimer molecule, obviously in the amine-dominated interior, not in the crown-ether periphery. 

Not content with such a laborious and time consuming enterprise, McCollum started, on his own initiative in 1908, the first rat colony in the United States to be devoted exclusively to the study of nutrition. More than five years later he was able to report that a successful diet for a rat required the inclusion of an ether extract of egg or butter. (15)... 

Crude and three diethyl ether extracted, acetone treated, fractions were isolated from large-scale cultures of Gambierdiscus toxicus. Crude extracts at. 04 mg/ml inhibited the histamine contraction response in smooth muscle of the guinea pig ileum. Three semi-purified fractions at 5 ng/ml, effectively inhibited the guinea pig ileum preparation. Two of these fractions followed Michaelis-Menten kinetics for a competitive inhibition. The third fraction inhibited in a non-reversible manner. This study has established the presence of three lipid extracted toxins in toxicus, outlined a method for their assay in small quantities, and identified at least two of the effects of these toxic extracts in animals. 

Pheromone (sex attractant). Ether extract of the stem, produced equivocal effect on Aspiculuris tetraptera, female and male Dacus dorsalis, male Mediterranean fruit flies, and male and female melon flies " k Pheromone (signaling). Ether extract of the stem, produced equivocal effect on Aspiculuris tetraptera, female and male Dacus dorsalis, male Mediterranean fruit flies, and male and female melon flies " k Phospholipidemic effect. Oil, administered to phospholipids transfer protein knockout (PLTPO)-deficient mice, produced an increase of phospholipids and free cholesterol in the VLDL-LDL region of PLTPO mice. Accumulation of phospholipids and free cholesterol was dramatically increased in PLTPO/HLO mice compared to PLTPO mice. Turnover studies indicated that coconut oil was associated with delayed catabolism of phospholipids and phospho-lipids/free cholesterol-rich particles. Incubation of these particles with hepatocytes of coconut-fed mice produced a reduced removal of phospholipids and free cholesterol by SRBI, even though SRBI protein expression levels were unchanged . 

Polypropylene. A similar study on polypropylene is interesting because polypropylene has a molecular structure intermediate between polyethylene and polyisobutylene. An atactic polypropylene specimen was prepared by ether extraction and irradiated in a nitrous oxide atmosphere. The changes in gel fraction (insoluble in hot xylene) as a function of N-jO pressure are shown in Figure 6. Gel formation (cross-linking) of polypropylene is also promoted in the presence of nitrous oxide. 

The concentration procedure was performed on the sample within 3 days of arrival at the laboratory. Upon arrival, all ether extract samples were stored at —10 °C in a freezer. The ether elution after the water was frozen out was further dried by passage through anhydrous sodium sulfate. The sample was then concentrated by a Kudema-Danish evaporator to 2 mL. After concentration, 1.0 mL of the 2-mL concentrated sample was base extracted to remove the chemicals interfering with the capillary GC analysis. The base extraction procedure developed in this study is the following ... 

Other preliminary experiments on alkali lignin included oxidations by barium peroxide and alkali (5, 6), alkali fusion, and alkali fusions in the presence of calcium peroxide, sodium borate perhydrate, and monopersulfate compound. Ether extractives and water extractives were examined, but in all cases too many of the oxidation products obtained were new and unidentifiable, and it was impossible to evaluate the experiments adequately with the available techniques. Vanillic acid appeared to be the chief oxidation product under conditions which did not demethylate further or destroy the aromatic nature of the oxidation products. Some oxidation conditions yielded p-hydroxybenzyl moieties as products, and some gave no trace of these products whatever. More detailed studies of the ether-insoluble, water-soluble components of the several oxidation mixtures were postponed until adequate procedures were developed for analytical isolation and identification. 

Fusion with Alkali and Cupric Oxide in Nonaqueous Solvents. Alkali lignin was fused with potassium hydroxide and cupric oxide in methanol under conditions suggested by Tiemann (20) and in n-amyl alcohol as suggested by Klages (4). These procedures were very effective in earlier model compound studies in our laboratories (12). Ether extracts obtained were less than those from corresponding experiments in aqueous solution, and qualitative compositions were essentially the same. In the case of the amyl alcohol experiments, artifacts with the cupric oxide were obtained. Again, experiments were conducted under more dilute conditions in a bomb under superatmospheric conditions, but results were no better. 

This review groups the information published on degradation of the main families of extractants studied in the frame of long-lived minor-actinide and fission-product recovery (1-4) (see Chapter 1) alkyl-phosphorus compounds (phosphates, phosphonic acids, bifunctional compounds like CMPO), amide compounds (dialkyl-amides, malonamides, and diglycolamides), N-donor compounds, and macrocycles like crown ethers and calixarenes (Table 8.1). The multicomponent systems based on the chlorinated cobalt dicarbollide process have not been considered. 

Hull-less barley varieties have been developed, in which the hull separates during threshing. These varieties contain more protein and less fibre than conventional barley, and theoretically should be superior in nutritive value to conventional barley. However, Ravindran et al. (2007) found that the ME (N-corrected basis) was similar in hull-less and hulled barley. The chemical composition of six Brazilian hull-less barley cultivars was studied by Helm and de Francisco (2004) and reported as follows. The highest constituents were starch (575-631 g/kg), crude protein (125-159 g/kg) and total dietary fibre (TDF 124-174g/kg), the starch and crude protein contents being in agreement with those previously reported for Swedish (Elfverson et al., 1999) and Canadian (Li et al., 2001) varieties. The other reported values (g/ kg) were ash content 15.1-22.7, ether extract 29.1M0.0, starch 574.6-631.4, insoluble dietary fibre 80.7-121.6, soluble dietary fibre 43.0-64.5 and p-glucan 37.0-57.7. 

In another study, 13-carotene was heated in aqueous medium at 90°C, 120°C and 150°C. More than 40 different compounds were found in the ether extracts by GC-MS as shown in Figure 3. Dihydroactinidiolide (sweet peachy aroma) was found in highest concentration at all temperatures studied. At 90°C, 5-6-epoxy-6-ionone (sweet, violet-like) was found in second highest quantity, while at 150°C, 2,6,6-trimethyl-2-hydroxy-cyclohexanone (green, citrusy) and 2,6,6-trimethyl-2-hydroxy-cyclohexan-1-aldehyde (floral, geraniol-like) were found in large quantity. At 120°C, these compounds were more evenly balanced than at 90°C or 150°C. A balance of ionone related compounds seem to contribute to an attractive green tea flavor. 

This extraction study did however, point out a potential problem with reverse phase analysis. Direct extraction of plasma with benzene-isopropanol at pH 4 followed by HPLC analysis produced increasing pressures, losses in resolution and sensitivity in a short period of time. Further work demonstrated that this effect was related to lipoidal material in plasma. A preliminary extraction with petroleum ether at ambient pH prior to acidifying and extracting with benzene-isopropanol alleviated this problem. 

General Changes in Corn Grain Composition. Samples of 18 varieties of corn, including hybrids and native varieties from distinct geographical areas of Mexico, were studied (see Figure 3 and Table IV). From Tables V and VI the most notable differences between the untreated and lime-treated corns are demonstrated an increase in mineral content and decreases in total protein, crude fiber, and ether extract. 

Sreekala and Jayachandran (2004) conducted studies on different levels of shade and maturity stage and its effect on the volatile oil and non-volatile ether extract. In general, volatile oil was highest under heavier shade levels (60 and 80%) and non-volatile ether extract was highest under 20% shade. They concluded that shade had a positive influence... 

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