Search results for "Kinetic"
showing 10 items of 3064 documents
Sorption kinetic of aroma compounds by edible bio-based films from marine-by product macromolecules: Effect of relative humidity conditions
2019
International audience; Edible films based on gelatin and chitosan have high gas and aroma barrier properties. This study focused on their capability to sorbed/retain aroma compounds (1-hexanal, 2-hexen-1-ol, 1-hexanol, 3-hexanone and phenol) at three relative humidity level (≤2%, 53% or 84% RH). Whatever the relative humidity condition, the order of sorption is keton (3-hexanone) < aldehyde (1-hexanal) < aliphatic alcohols (2-hexen-1-ol and 1-hexanol) < phenol. This order could be related to the intrinsic chemical properties of aroma compounds. The increase in moisture enhanced the sorption at the highest RH for all the aroma compounds. However, a competition between water and aliphatic al…
Flavour release at the interfaces of stirred fruit yoghurt models
2006
Abstract Model matrices consisting of a pectin and a dairy gel were investigated to study the transfer of flavour compounds between the different phases of stirred fruit yoghurt. Using a full factorial experimental design, different parameters (storage temperature, initial flavour concentration in the pectin gel and fat content of the dairy gel) were studied. The kinetics of the migration of flavour compounds between the two gels were investigated using a novel SPME method, where a Carboxen/Polydimethylsiloxane fibre was directly inserted into the pectin gel. Flavour compounds were predominantly retained in the pectin gel and thus, the presence of fat in the dairy gel did not affect their t…
Effects of heat treatment and acid-induced gelation on aroma release from flavoured skim milk
2010
Abstract Time dependent aroma release was studied in skim milk, heated skim milk as well as in acid-induced gels derived from them using static headspace – gas chromatography analysis. A variable order kinetic model was fitted to experimental data and was used to determine headspace equilibrium concentration and initial rates of release. When compared to water, retention in milk based matrices was increased for hydrophobic aroma compounds, while it was decreased for more hydrophilic volatiles. Acid gelation reduced the initial rate of aroma release by a factor varying from 2.0 to 3.8, depending on the compound. Positive deviation from the first order kinetics was observed and suggests that …
Retention/release equilibrium of aroma compounds in fat-free dairy gels
2010
BACKGROUND: The replacement of fat by thickeners in fat-free yoghurts leads to an important modification of aroma compound partitioning, with an impact on aroma perception. Investigation of retention/release equilibria allows a good understanding of aroma compound behaviour depending on food composition. RESULTS: Vapour/liquid equilibria of ten aroma compounds (two esters, two ketones, three aldehydes and three alcohols) in several media were studied to investigate the influence of pectin addition to fat-free dairy gel on the retention/release equilibrium. The partition coefficient of each aroma compound was measured by headspace analysis at equilibrium in six media (pure water, low-methoxy…
Effect of cytochrome P450 inhibitors (diethyl dithiocarbamate, ketoconazole and grapefruit juice) on the pharmacokinetics of all-trans-retinoic acid.
2004
Diethyl dithiocarbamate (DEDTC) has been reported to be a more powerful inhibitor of all-trans-retinoic acid (ATRA) in vitro metabolism than the well-established cytochrome P450 (CYP) inhibitor ketoconazole (KC). In recent years grapefruit juice (GJ) has been shown to be able to increase the oral bioavailability of several drugs by inhibiting intestinal CYP. This study investigated the in vivo effect of these CYP inhibitors on the pharmacokinetics of ATRA. The latter was administered to rats as a constant-rate intravenous (i.v.) infusion (0.48 mg h(-1) kg(-1)) during 10 h and orally (1.6 mg kg(-1)). DEDTC (320 mg kg(-1) x 2 i.v., 6.4 and 32 mg kg(-1) per os (p.o.)) did not change the ATRA c…
Muscular Strength Imbalances Are not Associated with Skin Temperature Asymmetries in Soccer Players
2020
Although strength imbalances using isokinetic dynamometer have been examined for injury risk screening in soccer players, it is very expensive and time-consuming, making the evaluation of new methods appealing. The aim of the study was to analyze the agreement between muscular strength imbalances and skin temperature bilateral asymmetries as well as skin temperature differences in the hamstrings and quadriceps. The skin temperature of the anterior and posterior thigh of 59 healthy male soccer athletes was assessed at baseline using infrared thermography for the identification of hamstrings-quadriceps skin temperature differences and thermal asymmetries (>
The effect of heat treatment on the morphology and mobility of Au nanoparticles
2020
This work was supported by The Centre National de la Recherche Scientifique (CNRS) of France and the French Embassy Program. The authors are also grateful for partial support by COST Action CA15216, the Estonian Science Foundation (grants PUT1689 and PUT1372), the Estonian Centre of Excellence in Zero Energy and Resource Efficient Smart Buildings and Districts, ZEBE, grant 2014-2020.4.01.15.0016 and Latvian Science Council grant lzp-2018/2-0083.
Nonlinear nystagmus processing causes torsional VOR nonlinearity.
2003
The eye movement component that rotates around the line of sight, i.e., the ocular torsion, is in many aspects different from horizontal and vertical eye movements. While ocular torsion is mediated only by reflexive pathways like the torsional vestibulo-ocular and optokinetic reflexes (TVOR and OKN, respectively), horizontal and vertical components are also subject to intentional control mechanisms that are mediated by the saccadic and the pursuit systems. Dynamic properties of torsional eye movements are also very distinct. While horizontal and vertical VOR components show a gain close to unity and a small neural integration leakage with a time constant around pi=30 s, the TVOR shows a sma…
Penetration of 2% cyclosporin eyedrops into human aqueous humour.
1989
The penetration into the eye and the systemic absorption of 2% cyclosporin eye drops were determined by polarisation immunofluorescent assay of cyclosporin in the aqueous humour and plasma of 30 patients at the time of cataract surgery. The results were then compared with the corresponding results after oral administration at a dosage of 5 mg/kg/day to three further patients. The maximum intraocular concentration (24 (SD 9) mg/l) was achieved four hours after topical administration. This level was slightly less than that found in aqueous humour (28 (SD 10) mg/l) 12 hours after systemic administration of the drug at a dosage of 5 mg/kg/day. Both these levels are below the minimum therapeutic…
Translocation of Cations During Sorption of Copper in the System Solution - Algae (Spirogyra sp.)/Translokacja Kationów Podczas Procesu Sorpcji Miedz…
2014
Zbadano kinetykę procesu sorpcji kationów miedzi w glonach Spirogyra sp. oraz towarzyszące mu procesy sorpcji kationów wodorowych i procesy uwalniania do roztworu kationów związanych w glonach: Na+, Mg2+, K+ i Ca2+. Stwierdzono, że w układzie statycznym, przy stałym stosunku masy glonów do objętości roztworu, procesy te zachodzą równocześnie, przy czym należy przypuszczać, że ilość uwalnianych soli ma wpływ na parametry heterofazowej równowagi wymiany jonowej. W warunkach prowadzenia eksperymentu ilość uwolnionych kationów była blisko 10-krotnie większa niż ilość kationów sorbowanych. Porównano parametry równowagi wyznaczone z modelu reakcji pseudo-drugiego rzędu z parametrami uzyskanymi po…