We study the electric double layer by combining the effects of ion finite size and dielectric decrement. At high surface potential, both mechanisms can cause saturation of the counter-ion concentration near a charged surface. The modified Grahame equation and differential capacitance are derived analytically for a general expression of a permittivity ε(n) that depends on the local ion concentra...

The effect of pretreatment with graded concentration of diltiazem on the inotropic responses to amrinone were studied on isolated atria of rabbit. The responses to amrinone were modified by diltiazem in a biphasic manner; initial potentiation followed by inhibition. The potentiation is proposed to be due to synergistic rise in cytosolic calcium ion concentration by diltiazem and amrinone. The i...

A sequential injection chromatography (SIC) constructed from a short monolithic column and a microfluidic polymer chip with an embedded Cl ion-selective electrode (Cl-ISE) as a detector was developed for simultaneous determination of common inorganic anions. Under the optimal flow conditions of the SIC system, the determination range for Cl, NO2 , Br, NO3 ions was as follows: For Cl ion in a co...

We investigate the effects of adding periodic stimulation to a generic, conductance-based neuron model that includes ion concentration dynamics of sodium and potassium. Under conditions of high extracellular potassium, the model exhibits repeating, spontaneous, seizure-like bursting events associated with slow modulation of the ion concentrations local to the neuron. We show that for a range of...

The ionic current flowing through a protein channel in the membrane of a biological cell depends on the concentration of the permeant ion, as well as on many other variables. As the concentration increases, the rate of arrival of bath ions to the channel's entrance increases, and typically so does the net current. This concentration dependence is part of traditional diffusion and rate models th...

a nanocomposite membrane cu2+ ion-selective electrode has been constructed using a new compound ethyl 1,2,3,4-tetrahydro-4-(4-methoxyphenyl)-6-methyl-2-oxopyrimidine-5-carboxylat (etmoc) as a neutral ionophore. the electrode works properly. it responds to cu2+ ion with a sensitivity of 29.5 ± 0.2 mv/decade over the range 1.0 × 10−9 to 5.0 × 10−1m at ph 3.0-8.0. the limit of detection was 4.5 × ...

In this paper, grafting of acrylic acid monomer on Gum tragacanth was performed. Variable of experiment included concentration of initiators and monomer, time, and temperature. Grafting efficiency was measured in the term of percentage of grafting (%G) and percentage of grafting efficiency (%E). Effectiveness of grafted gum in ferrous ion removal at different condition was assessed. According t...

Using the mixed solvents, (water +ethanol + propanol), the solubility of CdF2 was determined byevaporating method at 25° C. The results showed that the sollbility, s, of CdF2 decreases bydecreasing the dielectric constant of the mixed solvent .Once the solubility of CdF2 was determined,the concentration solubility product, Ksp(c)=4s3, was calculated .Furthermore ,by estimating the meanactivity ...