Increasing Salt Concentration (increasing + salt_concentration)

Distribution by Scientific Domains

Selected Abstracts

Detection of Konjac glucomannan by immunoassay

Ian P. Hurley
Summary Konjac glucomannan is a hydrocolloid that has been used in food applications. The European ban on the use of Konjac glucomannan means that the detection and analysis has potential applications in the food industry, particularly detection of food adulteration. The aim of this work was to develop an assay capable of detecting Konjac glucomannan as an isolated sample and within food matrices. An indirect competitive ELISA was developed utilising a polyclonal antibody raised against Konjac glucomannan. The ELISA was found to be specific for Konjac glucomannan and sensitive, with a detection limit of 0.1 ng mL,1. Increasing salt concentration and freeze/thaw cycles did not affect the performance of the assay. The ELISA was able to detect Konjac glucomannan in admixtures with other gums and also in confectionery that had been spiked with Konjac glucomannan. The ELISA has potential as a kit for the differentiation of Konjac glucomannan from other hydrocolloids and detection in food. [source]

Effects of ionic strength on lysozyme uptake rates in cation exchangers.

I: Uptake in SP Sepharose FF
Fluorescence scanning confocal microscopy was used in parallel with batch uptake and breakthrough measurements of transport rates to study the effect of ionic strength on the uptake of lysozyme into SP Sepharose FF. In all cases the adsorption isotherms were near-rectangular. As described previously, the intraparticle profiles changed from slow-moving self-sharpening fronts at low salt concentration, to fast-moving diffuse profiles at high salt concentration, and batch uptake rates correspondingly increased with increasing salt concentration. Shrinking core and homogeneous diffusion frameworks were used successfully to obtain effective diffusivities for the low salt and high salt conditions, respectively. The prediction of column breakthrough was generally good using these frameworks, except for low-salt uptake results. In those cases, the compressibility of the stationary phase coupled with the shrinking core behavior appears to reduce the mass transfer rates at particle-particle contacts, leading to shallower breakthrough curves. In contrast, the fast uptake rates at high ionic strength appear to reduce the importance of mass transfer limitations at the particle contacts, but the confocal results do show a flow rate dependence on the uptake profiles, suggesting that external mass transfer becomes more limiting at high ionic strength. These results show that the complexity of behavior observable at the microscopic scale is directly manifested at the column scale and provides a phenomenological basis to interpret and predict column breakthrough. In addition, the results provide heuristics for the optimization of chromatographic conditions. 2005 Wiley Periodicals, Inc. [source]

Ion,Dipole Interactions in Concentrated Organic Electrolytes

CHEMPHYSCHEM, Issue 6 2003
Alexandre Chagnes
Abstract An algorithm is proposed for calculating the energy of ion,dipole interactions in concentrated organic electrolytes. The ion,dipole interactions increase with increasing salt concentration and must be taken into account when the activation energy for the conductivity is calculated. In this case, the contribution of ion,dipole interactions to the activation energy for this transport process is of the same order of magnitude as the contribution of ion,ion interactions. The ion,dipole interaction energy was calculated for a cell of eight ions, alternatingly anions and cations, placed on the vertices of an expanded cubic lattice whose parameter is related to the mean interionic distance (pseudolattice theory). The solvent dipoles were introduced randomly into the cell by assuming a randomness compacity of 0.58. The energy of the dipole assembly in the cell was minimized by using a Newton,Raphson numerical method. The dielectric field gradient around ions was taken into account by a distance parameter and a dielectric constant of ,=3 at the surfaces of the ions. A fair agreement between experimental and calculated activation energy has been found for systems composed of ,-butyrolactone (BL) as solvent and lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate (LiAsF6), and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) as salts. [source]

Highly Cooperative Behavior of Peptide Nucleic Acid-Linked DNA-Modified Gold-Nanoparticle and Comb-Polymer Aggregates

Abigail K. R. Lytton-Jean
PNA is used to assemble gold nanoparticles,DNA and polymer,DNA hybrids into highly cooperative aggregates with sharp melting transitions. The melting temperatures of these aggregates are found to increase with increasing salt concentrations, while the opposite trend is observed for unmodified PNA:DNA duplexes. This cooperative behavior is attributed to the presence of closely spaced duplexes inside the aggregate. [source]

High salt-treatment-induced Na+ extrusion and low salt-treatment-induced Na+ accumulation in suspension-cultured cells of the mangrove plant, Bruguiera sexangula

M. Kura-Hotta
Abstract A suspension-cultured cell strain of the mangrove plant (Bruguiera sexangula) was established from a callus culture and maintained in an amino acid medium in the absence of NaCl. NaCl non-adapted cells were transferred to media containing 0,200 mm NaCl. The initial growth rate decreased gradually with increasing salt concentrations. However, at up to 150 mm NaCl, cell number growth at the highest point was almost the same as that at lower salt concentrations. Cells even continued to grow in the presence of 200 mm NaCl. Cells incubated in a medium containing 50 mm NaCl for 3 weeks accumulated Na+, while those incubated in 150 mm NaCl for 2 d showed only a transient increase in Na+ and Cl, concentrations. In the latter treatment, the intracellular concentration of Na+ returned to the original low level within 2 weeks. It took a longer time for Cl, to return to its original level. As a result, the Na+ and Cl, concentrations in cells cultured with 50 mm NaCl were much larger than those in cells cultured with 150 mm NaCl. The intracellular distribution of ions after transfer to the medium containing 150 mm NaCl was analysed by isolating the vacuoles. Treatment with amiloride, an inhibitor of the Na+/H+ antiporter, suppressed the recovery of Na+ to the original level in the cells. Treatment with 150 mm NaCl for 3 d stimulated the activities of both the vanadate-dependent H+ -ATPase and the Na+/H+ antiporter in the plasma membrane fraction. [source]