Total under plasma activation conditions

Total Oxidation under Plasma Activation Conditions in Gas... 

The high efficiency may be better understood if one recognizes that in a mixture of silicon tetrachloride and oxygen the chemical equilibrium is totally shifted to silica at the temperatures we apply. The activation energy for the reaction prevents the thermal reaction from proceeding rapidly under the experimental conditions chosen. Thus the plasma merely acts as a catalyst to overcome the activation energy of the reaction. 

We have previously shown that levels of tracer zinc In plasma, red blood cells, whole blood(21) or urlne(22) are closely correlated with absorption when measured under specific controlled conditions. These conditions Include measurement of subjects fasted overnight and oral administration of carrier free tracer. The relationship between plasma Zn-69m activity and absorption estimated from total body retention of Zn-69m was determined... 

A variety of hydrolases catalyze the hydrolysis of acetylsalicylic acid. In humans, high activities have been seen with membrane-bound and cytosolic carboxylesterases (EC 3.1.1.1), plasma cholinesterase (EC 3.1.1.8), and red blood cell arylesterases (EC 3.1.1.2), whereas nonenzymatic hydrolysis appears to contribute to a small percentage of the total salicylic acid formed [76a] [82], A solution of serum albumin also displayed weak hydrolytic activity toward the drug, but, under the conditions of the study, binding to serum albumin decreased chemical hydrolysis at 37° and pH 7.4 from tm 12 1 h when unbound to 27 3 h for the fully bound drug [83], In contrast, binding to serum albumin increased by >50% the rate of carboxylesterase-catalyzed hydrolysis, as seen in buffers containing the hydrolase with or without albumin. It has been postulated that either bound acetylsalicylic acid is more susceptible to enzyme hydrolysis, or the protein directly activates the enzyme. 

The silicon carbide-based ceramic layer is obtained by CVD activated by a microwave plasma (2.45 GHz) on the tantalum previously cleaned by an argon plasma (56 min, 133 Pa, 250 W) at a temperature identical to the deposition temperature (T = 570°C), lower than the substrate annealing temperature. After readjustment of the total pressure and microwave power by introduction of a precursor (TMS) in the argon flow, the SiC coating is produced under selected conditions (66 Pa, TMS/Ar = 0.2/5.5 l.h-, T = 570°C, 350 W) derived from a previous parametric study. Coatings obtained then presented low dry friction coefficients. The mechanical properties, which are essential in order to be able to appreciate the mechanical stability, were acquired by several methods ... 

Since plasma lipoprotein cholesterol must be the major substrate for bile acid biosynthesis under conditions when the rate of hepatic synthesis of cholesterol is low, regulation of the uptake of lipoprotein cholesterol by the hepatocytes should be of importance not only for the rate of cholesterol synthesis but also for the activity of cholesterol 7a-hydroxylase. It should be mentioned that bile acids are included among the different factors known to be able to modulate the receptor-mediated uptake of cholesterol by the apo-B, E or LDL receptor. The apo-B, E receptor can thus be induced to high levels by treatment with a bile acid sequestrant ]259]. Angelin et al. have shown that preparation of a bile fistula in adult dogs markedly induced the expression of the apo-B, E receptor and that the binding of this receptor could be almost totally abolished by reinfusion of taurocholate [260]. 

The total number of polypeptides in the culture medium was 8-20 bands according to electrophoretic analysis (Figure 1). The protein export was inhibited by actinomycin D, cycloheximide, 2-deoxy-D-glucose and also by concanavalin A (Con A). In the presence of Con A (400 pg/ml), the enzymes were accumulated entirely inside the cells but not in the periplasm or the cell wall (Figure 2). At the same time the lectin had no influence upon cell growth and expression of invertase and acid phosphatase associated with the cell envelope. The activity accumulated inside Con A - treated cells was released into the culture medium on a-methylmannoside addition (Figure 3). The process was not affected by cycloheximide but was inhibited by sodium azide. The effect of Con A appears to be conditioned by its interaction with the plasma membrane of intact cells. Besides Con A, we detected peroxidase interaction with the plasmalemma of intact cells and alkaline phosphatase internment under physiological conditions. 

ESR measurements have been used to determine levels of transferrin in human plasma samples (Pocklington et al, 1977). An ESR study of the oxidation rates of iron transferrin by ceruloplasmin in the presence of ferrous ions shows that under normal conditions the transferrin appears to be able to deal readily with iron turnover (Foster et al, 1977). Since there is considerably more transferrin than ceruloplasmin in plasmas, on a competitive basis the oxidase activity of transferrin will be greater than that due to ceruloplasmin, except in cases where the total iron-binding capacity of the blood is saturated with iron. 

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