Fractions studies, rich

Within the frame of the present first series of experiments it was almost always oxygen which was injected into supercritical water-methane mixtures. There were several reasons for this first choice. One of these was the desire, to study rich flames and their possible products first. Often the water to methane mole fraction ratio was 0.7 to 0.3. But mixtures down to a methane mole fraction of 0.1 were also used. It was possible, however, to inject oxygen and methane simultaneously into the supercritical water and produce a flame. Not possible was the production of true premixed flames. After a retraction of the thin inner nozzle capillary of the burner (see Fig. 1 b) the two gases could be mixed just below the reaction cell, but the flame reaction proceeded from the nozzle tip in the cell back towards this mixing point immediately. 

Aromatic EC5-EC9 Fraction. Studies with humans and animals exposed predominately to vapors of individual BTEXs (there are fewer data for oral and dermal exposure) indicate that, following absorption, compounds in this fraction are widely distributed, especially to lipid-rich and highly perfused tissues (see ATSDR 1994, 1995d, 1997a, 1999a). Studies of rats exposed by inhalation to single hydrocarbons at 100 ppm, 12 hours/day, for 3 days found that C6-C10 aromatics (benzene, toluene, xylene, trimethylbenzene, and f-buty I benzene), compared with C6-C10 -alkanes ( -hexane... 

Some active species have been studied and their pharmacological activity confirmed in different experimental models. In general, the active fractions of such plants were those containing cucurbitacins, as demonstrated by Rios et al. [10] in their work with Cayaponia tayuya roots. This species is used in the Amazon region of South America as an analgesic, anti-inflammatory, and anti-rheumatic agent while the extracts of this species are widely employed in the treatment of skin disorders such as dermatosis and other irritations. The chloroform fraction obtained from the active root methanol extract was found to be more active than the ethyl acetate and butanol fractions. Subsequent phytochemical analysis demonstrated that the chloroform fraction is rich in cucurbitacins, whereas the ethyl acetate and butanol fractions are principally comprised of C-glycosil flavonoids [10]. 

Although the total content of carbohydrate fractions of the three components is similar, as reported by Williams et al., 1990, it was found that protein-rich fractions have a significantly lower glucuronic acid content. Circular dichroism studies conducted on different GA fractions showed that only the AGP and GP components have a secondary structure (Renard et al., 2006). The AGP fraction was isolated by gel filtration chromatography and subjected to deglycosylation with hydrofluoric acid (HF) to separate the protein (Qi et al., 1991). About 400 amino acids were contained by the AGP protein fraction ( 33% are... 

Vertebrate liver is a very rich source of enzymes that metabolize lipophilic xenobiotics, and subcellular fractions are prepared to study metabolism. Sometimes, other tissues such as brain, kidney, testis, and ovary are also treated in this way. A typical subcellular fractionation of liver might be as follows ... 

For the analysis of the chemical structure of flames, laser methods will typically provide temperature measurement and concentration profiles of some readily detectable radicals. The following two examples compare selected LIF and CRDS results. Figure 2.1 presents the temperature profile in a fuel-rich (C/O = 0.6) propene-oxygen-argon flame at 50 mbar [42]. For the LIF measurements, 1% NO was added. OH-LIF thermometry would also be possible, but regarding the rather low OH concentrations in fuel-rich flames, especially at low temperatures, this approach does not capture the temperature rise in the flame front [43]. The sensitivity of the CRDS technique, however, is superior, and the OH mole fraction is sufficient to follow the entire temperature profile. Both measurements are in excellent agreement. For all flames studied here, the temperature profile has been measured by LIF and/or CRDS. 

The feasibility of reusing the phase transfer catalyst via the reuse of the third liquid phase in a tri-liquid catalytic system has been investigated in our laboratory [6,7]. In the present study, the catalyst-rich liquid phase was repeatedly used for four times and the changes in the conversion of RBr and the fractional yield of ROAc were observed. 

In the last few decades, several epidemiological studies have shown that a dietary intake of foods rich in natural antioxidants correlates with reduced risk of coronary heart disease particularly, a negative association between consumption of polyphenol-rich foods and cardiovascular diseases has been demonstrated. This association has been partially explained on the basis of the fact that polyphenols interrupt lipid peroxidation induced by reactive oxygen species (ROS). A large body of studies has shown that oxidative modification of the low-density fraction of lipoprotein (LDL) is implicated... 

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