Fractionator-absorber

Absorbed Fraction—A term used in internal dosimetry. It is that fraction of the photon energy (emitted within a specified volume of material) which is absorbed by the volume. The absorbed fraction depends on the source distribution, the photon energy, and the size, shape and composition of the volume. 

Initially the good relationship between the passive drug transport across Caco-2 cells and the absorbed fraction after oral administration to humans [5] may be... 

The complex relationship between the absorbed fraction and intestinal perme-... 

The blood levels following oral and intravenous doses are very low in all animal species. This, most likely, is due to the marked affinity of the drug for various tissues and the rapid hepatic extraction of the absorbed fraction. The main route of excretion is the bile. Less than 5 % of the dose are recovered in the urine of intact animals after oral or intravenous administration. 

The imaginary part of the dielectric function describes the optical absorption in PS and thereby gives information about the bandgap. Details of the optical transitions responsible for absorption and emission of photons in Si are shown in Fig. 7.12 and will be discussed in the next section. The absorbed fraction P(x) of the non-reflected light intensity P depends on the sample thickness % and on the absorption coefficient a according to... 

Another therapeutic class to be briefly discussed is that of the lipid-lowering agents known as fibrates, e.g., clofibrate and fenofibrate (8.5). Here also, the acidic metabolite is the active form clofibrate (an ethyl ester) is rapidly hydrolyzed to clofibric acid by liver carboxylesterases and blood esterases [11], Human metabolic studies of fenofibrate (8.5), the isopropyl ester of fenofibric acid, showed incomplete absorption after oral administration, while hydrolysis of the absorbed fraction was quantitative [12], This was followed by other reactions of biotransformation, mainly glucuronidation of the carboxylic acid group. 

Absolute systemic bioavailabUity (absorbed fraction of the dose or concentration administered) can only be calculated by comparing the so-called Area Under the Plasma Curve (AUC, the area under the curve in a plot of the concentration of a substance in the plasma against time) after oral, inhalation, or dermal administration with the AUC after direct administration into the systemic circulation, e.g., after intravenous administration. In order to obtain a rehable estimate for AUC after single administration, it is necessary to have blood samples for 3-5 half-hves. In case data are not available for a calculation of the AUC, the absorbed fraction can be indicated from data on the amount of the parent compound and its metabohte(s) excreted in the urine, feces, and exhaled air. It should be noted that the amount excreted in the feces stems from both the unabsorbed fraction as well as from the fraction of the substance following bUiary excretion. 

Pyridine M Ligand ratio, N/Cu X 10 mole 1 min-1 Oxygen absorbed % Fractional Yields Intrinsic viscosity decil. g x... 

Other factors that determine the absorbed fraction of inhaled glucocorticoids include the age of the child, as lung deposition of inhaled drugs increases with age (80). Therefore, the minimum effective dose may fall as the child becomes older. Moreover, it is reasonable to hypothesize that systemic absorption will increase once asthma control is established (81). Furthermore, patient adherence and inhaler technique are two factors that can have a large influence on the amount of glucocorticoid inhaled and absorbed. 

If the absorption is multicomponent, the average equilibrium constant mave is determined for each of the solute components at the average temperature and pressure of the absorber, and a separate absorption factor Aave is defined for each component. These absorption factors can be used in Eq. (28) to define the absorbed fraction of the component. 

Sepharose and elution with lactose (Fig. 23). The UV-absorbing fraction that was eluted with the lactose solution was collected and the protein precipitated by addition of an equal volume of saturated ammonium sulfate. On refrigeration of the sample overnight, a white precipitate formed. This precipitate was collected by centrifugation and redissolved in 0.2 mL of 0.02 M phosphate buffer of pH 7 in saline. The agar-diffusion test shown in the inset of Fig. 23 showed that high-titer antibodies were produced that formed a precipitin complex with the antigen. Several affinity runs were made. The antibody samples were combined and lyophilized. The yield of anti-lactose antibody was 50 mg from 20 mL of serum. 

The UV-absorbing fractions eluted with NH4SCN from the column were combined and mixed with an equal amount of saturated (NH SO The precipitate that formed on refrigeration overnight was collected and redissolved in a small volume of phosphate buffer. 

The meals were extrinsically labelled by added 65 Zn. The rationale for this method is that a complete isotope exchange takes place between the added radioactive zinc isotope and the zinc present in the meal. Measurements of the uptake of radioactive iron isotopes in blood or in the whole body have been used for many years in studies of iron absorption. (12, 13, 14). The absorption in the present study is determined from measurement of the whole body retention of the radioisotope. However, this can not be done until the non-absorbed fraction of the isotope has left the body. During this periode of time some of the initially absorbed has been extrected. A correction of retention data... 

Fraction of a component in feed vapor that is not absorbed Fraction of a component in entering liquid that is not stripped Factor in Gilliland correlation... 

Fig. 5.16 shows the spectral irradiance E according to (5.37) for T = 1000 K and T = 5777 K. Here, the proportionality constants c were each chosen so that for both temperatures the maximum of E, which appears at Amax = C2/5T, was the same. The hatched areas in Fig. 5.16 are proportional to the absorbed fraction of the incident radiation flow, whilst the areas under the E curves correspond to the irradiance E. The desired hemispherical total absorptivity a T) is, according to (5.28) and (5.36) the ratio of these areas. For T = 1000 K an absorptivity close to a 2 will be expected. In contrast the largest portion of the solar radiation (T = 5777 K) falls in the region of small wavelengths... 

Drugs with a II absorption parameter greater than unity tend to be well absorbed (i.e., absorbed fraction >0.5), while drugs with II values of less than or equal to 1 are poorly absorbed (absorbed fraction <0.5). Thus, absorption is most efficient and hence drug-likeness more likely when the absorption parameter II is greater than unity. This most often occurs when the partition coefficient is greater than unity and/or the oversaturation number is equal to unity. 

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