Search results for "kinetics"

The impact of high-temperature, short-time thermal treatment on texture and weight loss of green asparagus

1997

The kinetics of the degradation of texture and loss of weight of green asparagus heated to between 100 and 130 °C was studied. The texture of the asparagus was evaluated with two types of cells fitted to a universal texturometer: one cell measured resistance to cutting with a wire and the other was a Kramer cell. The two methods enabled distinction between the different thermal treatments, although the Kramer cell gave information about the behaviour of parts of the spear further away from the tip. The thermally induced degradation of the texture and loss of weight followed first-order kinetics. With respect to the texture, the parameters obtained with the wire cell 2.5, 5 and 7.5 cm from t…

Surface Modification of Porous Polyethylene Implants with an Albumin-Based Nanocarrier-Release System

2021

Background: Porous polyethylene (PPE) implants are used for the reconstruction of tissue defects but have a risk of rejection in case of insufficient ingrowth into the host tissue. Various growth factors can promote implant ingrowth, yet a long-term gradient is a prerequisite for the mediation of these effects. As modification of the implant surface with nanocarriers may facilitate a long-term gradient by sustained factor release, implants modified with crosslinked albumin nanocarriers were evaluated in vivo. Methods: Nanocarriers from murine serum albumin (MSA) were prepared by an inverse miniemulsion technique encapsulating either a low- or high-molar mass fluorescent cargo. PPE implants …

Thermal Degradation of Green Asparagus Texture

2019

A cutting cell was developed to evaluate the texture of green asparagus by measuring its resistance to being cut with a wire. The cell was used in conjunction with a universal texturometer and improved on the single-point method of the Wilder fibrometer. Experimental conditions were determined for using the cell to measure the cutting resistance of asparagus subjected to different extents of heat treatment. Better discrimination between samples was obtained than with a Kramer cell. The fresh asparagus spears. were heated at temperatures between 70 and 100°C for different lengths of time and the kinetics of the degradation of texture was studied. A biphasic (two-component) behavior was obser…

Glucose uptake in germinating Aspergillus nidulans conidia: involvement of the creA and sorA genes

2003

d-Glucose uptake in germinating wild-typeAspergillus nidulansconidia is an energy-requiring process mediated by at least two transport systems of differing affinities for glucose: a low-affinity system (Km∼1·4 mM) and a high-affinity system (Km∼16 μM). The low-affinity system is inducible by glucose; the high-affinity system is subject to glucose repression effected by the carbon catabolite repressor CreA and is absent insorA3mutant conidia, which exhibit resistance tol-sorbose toxicity. An intermediate-affinity system (Km∼400 μM) is present insorA3conidia germinating in derepressing conditions.creAderepressed mutants show enhanced sensitivity tol-sorbose. The high-affinity uptake system ap…

Elimination and distribution of different substituted phenols by frog (Rana temporaria) and crayfish (Astacus leptodactylus)

1981

Atrazine uptake, elimination, and bioconcentration by periphyton communities and Daphnia magna: effects of dissolved organic carbon.

2001

The bioconcentration and toxicokinetics of atrazine in three different periphyton communities and in laboratory reared Daphnia magna were studied in natural and artificial waters with different dissolved organic carbon (DOC) concentrations and qualities. The exposure concentrations were similar to those short-lived peak concentrations found in contaminated waters. Atrazine uptake and elimination were very fast, and the bioconcentration was low both in periphyton and D. magna. The bioconcentration factors in D. magna were approx. 16% of those in periphyton. The uptake and elimination rates were also higher in periphyton than in Daphnia. The periphyton properties affected the bioconcentration…

Influence of hydrogen cations on kinetics and equilibria of heavy-metal sorption by algae—sorption of copper cations by the alga Palmaria palmata (Li…

2013

The influence of hydrogen cations on kinetics and equilibria of sorption of copper cations by the marine alga Palmaria palmata (Linnaeus) Weber & Mohr was studied under static conditions. The competitive effect of the H+ cations is described, which influenced the uncertainty of evaluation of the alga sorption capacity. Under static conditions, the variation of the Cu2+/H+ concentration ratio during sorption was found nonmonotonic. The Langmuir isotherm model was used to determine the sorption capacity of the alga, namely 12.4 mg g−1 of dry algae mass. A similar value was determined from the kinetic parameters of the ionic exchange which is considered a pseudo-second-order chemical reaction.…

In vivo ANALYSIS OF SLOW CHLOROPHYLL FLUORESCENCE INDUCTION KINETICS IN ALGAE: PROGRESS, PROBLEMS AND PERSPECTIVES

1993

Kinetics of citrate uptake in growing cells ofLeuconostocspp.

1996

Citrate uptake was studied in growing cells of Leuconostoc mesenteroides subsp. mesenteroides. A Michaelis-Menten pattern with the dianionic form of citrate as the limiting substrate has been proposed. It was validated for different fermentations varying the initial citrate concentrations and the pH medium. This latter did not modify the rate of the process which was clearly confirmed using experiments with resting cells. The model was used to compare the kinetics of citrate consumption between several strains of Leuconostoc mesenteroides subsp. mesenteroides, Leuconostoc mesenteroides subsp. cremoris and Leuconostoc lactis.

Stomatal anatomy coordinates leaf size with Rubisco kinetics in the Balearic Limonium

2019

Abstract Trait integration arises through both selection on functional coordination and shared developmental pathways. Different anatomical components must both work well and develop together to generate individuals with the appropriate physiology to survive and reproduce in their environment. In this study, we used a common garden experiment and Bayesian multilevel models to test whether stomatal anatomy coordinates leaf gas exchange, Rubisco kinetics, and leaf size across 10 closely related species of Limonium from the Balearic Islands. The results indicate that the anatomical determinants of maximum stomatal conductance, stomatal density and size, were functionally coordinated with Rubis…