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Determined Parameters (determine + parameter)

Distribution by Scientific Domains

Chemistry	60%

Selected Abstracts

Plasma lipoprotein concentrations in the dog: the effects of gender, age, breed and diet

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 6 2008
A. Pasquini
Summary Earlier studies of canine lipoprotein metabolism have frequently not taken into account such variables as age, gender, lifestyle or feeding status. In the last years, many changes to lifestyle and feeding of dogs have occurred. In this study, C-tot, C-HDL, C-LDL, triglycerides and lipoprotein fractions were determined in 251 healthy dogs by means of enzymatic methods and through the electrophoretic technique. All data were analysed by multifactor anova test to determine which factors (age, gender, breed and diet) have a statistically significant effect (p < 0.05) on the determined parameter and subsequently Bonferroni's test was applied where necessary. Gender, age, breed and diet can significantly affect lipid metabolism, in particular lipoproteins involved in cholesterol plasma transport; on the contrary, triglycerides are not influenced by the same factors. The most important observation about age is the high level of C-LDL in puppies under 1 year of age. The highest cholesterol concentrations are found in Rottweiler but high values of plasma cholesterol are found also in Pyrenees Mountain dog and a great level of C-LDL in Labrador. Diet has shown a great influence on lipidic metabolism: dogs fed with different high-quality dry foods had significant differences in plasma cholesterol values (C-tot, C-HDL, C-LDL,), in particular, dogs fed with a diet rich in fish and fish-by-products have shown the lowest levels of C-tot, C-HDL and C-LDL. [source]

Carbohydrate-Deficient Transferrin (CDT) and HDL Cholesterol (HDL) Are Highly Correlated in Male Alcohol Dependent Patients

ALCOHOLISM, Issue 4 2000
Armin Szegedi
Background: Serum levels of total HDL cholesterol (HDL) are reportedly influenced by recent alcohol intake. We examined the correlation between HDL cholesterol and widely used markers of excessive alcohol intake, such as carbohydrate-deficient transferrin (CDT), ,-glutamyl-transferase (GGT), or mean corpuscular volume of erythrocytes (MCV), of which CDT is thought to be the most specific. Methods: Several serological markers [i.e., CDT, GGT, aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), MCV, and HDL] were determined in 100 actively drinking male patients with alcohol dependence (DSM-IV) and in 27 non-alcohol-dependent controls, according to routine procedures. Spearman,s rank correlation coefficients were calculated. Results: We found a highly significant positive correlation between HDL and CDT (rs= 0.55;p < 0.0005) in patients, but not in controls (rs= 0.13;p= 0.51). HDL was also positively correlated with GGT, ALAT, ASAT, and MCV only in patients. Conclusions: HDL cholesterol, as a widely determined parameter, may represent a useful routine marker for recent excessive alcohol intake. High HDL cholesterol levels should alert clinicians to investigate a patient's recent pattern of alcohol consumption. [source]

Modeling of extraction behavior of docosahexaenoic acid ethyl ester by utilizing slug flow prepared by microreactor

AICHE JOURNAL, Issue 8 2010
Eiji Kamio
Abstract The liquid,liquid extraction dynamics of an ethyl ester of docosahexaenoic acid (DHA-Et) with silver ion was investigated. The kinetic model was derived according to the following stepwise processes: Diffusion of DHA-Et across the organic film, complex-formation between DHA-Et and silver ion at the interface, and diffusion of extracted complex across the aqueous film. The kinetic parameters for the complex-formation reaction were determined from the investigation with the stirred transfer cell. With the proposed model and determined parameters, we predicted the uptakes of DHA-Et for the extraction system utilizing a slug flow prepared by a microchip. The calculated uptakes showed good correlation to the experimental data. The theoretical investigation suggested that the fast equilibration realized for the slug flow extraction system was due to the large specific interfacial area of the slug caused by the presence of wall film and the thin liquid film caused by the internal circulation. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source]

Comparing flow-reversal and inner recirculation reactors: Experiments and simulations

AICHE JOURNAL, Issue 7 2003
Moshe Ben-Tullilah
The operation of reactors with flow reversal operate similar to a reactor with internal recirculation, which the feed enters through one (say, inner) reactor and then turns around and flows out through (the outer) another, when the heat-transfer coefficient between the tubes is large. In this study, we compare the behavior of a packed-bed reactor operating in flow-reversal or internal-recirculation modes, using ethylene oxidation on Pt/Al2O3 as a model reaction. The reactor was built from two concentric tubes (with 28.5 and 42.5 mm in diameter), both packed with a 20 cm catalytic bed and 10 cm inert beds (of alumina-pellets) on each side. An adjustable opening between the tubes allowed for an internal recycle mode and the whole system could be operated with periodic flow reversal. The reactor can be employed then either as a simple once-through bed or as a bed with flow reversal in the inner tube or as bed with internal recirculation flowing from the inner to outer tube, or in the opposite direction, as well as an internal-recirculation reactor with flow reversal. Due to heat losses, the latter two modes were inferior to the others. The experiments, backed by simulations using a homogeneous model with independently determined parameters, showed that the technically-simpler inner-outer internal-recycle reactor operated better at low flow rates, than that with flow reversal, but the conclusion is reversed at high flow rates. The domain where the internal-recirculation reactor is superior depends on the heat-transfer coefficient between the streams. By lowering the feed concentration, the extinction point was determined for each mode highlighting again the conclusions drawn above that inner-recirculation operation may be superior to flow reversal at low flow rates. Simulations revealed also the existence of solutions with stationary fronts or oscillatory fronts. [source]

Flat bulk-solvent model: obtaining optimal parameters

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2002
Andrei Fokine
A bulk-solvent correction is regularly used for macromolecular refinement. The flat model of the bulk solvent is considered to be the most reliable. It is shown that the standard procedure does not always result in the optimal values of the bulk-solvent correction parameters. A method to obtain the best values for parameters ksol and Bsol of the flat-solvent model is discussed. The values of correctly determined parameters for crystallographic structures deposited in the Protein Data Bank are clustered around ksol = 0.35,e,Å,3 and Bsol = 46,Å2, which have a reasonable physical meaning. Such a distribution allows the use of these mean values of solvent parameters for many practical applications when refined parameters cannot be obtained, especially when an atomic model in the unit cell is not yet known. [source]