As pointed out by Appelo (1996), multicomponent ion exchange models have not been widely used in geochemical or geochemical transport modeling of subsurface processes, despite their recognized importance in regulating soil and sediment pore water compositions. This is also somewhat surprising considering the demonstrated success of ion exchange models in describing sorption and subsurface trans...

The effect of adenosine on Na+/H+ exchange activity was examined in cultured A6 renal epithelial cells. Adenosine and its analogue N6-cyclopentyladenosine (CPA) had different effects on Na+/H+ exchange activity depending on the side of addition. Basolateral CPA induced a stimulation of Na+/H+ exchange activity that was completely prevented by preincubation with an A2A-selective antagonist, 8-(3...

The existence of two populations of potential-operated Ca 2+ channels in the ureter smooth muscle have been suggested: (1) inactivating Ca 2+ channels which are responsible for the generation of action potentials and phasic contractions, and (2) non-inactivating Ca 2+ channels opened during sustained depolarization which are responsible for the generation of tonic tension (Kochemasova and Shuba...

the purpose of this study was to examine how four teachers used the seven processes of videotape analysis to develop an analytic approach and reflective thinking towards their teaching. the study was organized within video clubs and was used to describe the interactions among four teachers about their experiences at a language institute. data were gathered through videotaped recordings of lesso...

A generalization of the original Diffie-Hellman key exchange in (Z/pZ) found a new depth when Miller [27] and Koblitz [16] suggested that such a protocol could be used with the group over an elliptic curve. In this paper, we propose a further vast generalization where abelian semigroups act on finite sets. We define a Diffie-Hellman key exchange in this setting and we illustrate how to build in...

BACKGROUND Diabetes is one of the leading causes of illness and death for African Americans and people of African descent throughout the United States and in the city and county of Sacramento, California. The involvement of families and communities in developing prevention strategies can increase the likelihood that behavioral changes will be sustained. CONTEXT Three member organizations of t...

If the AdS/CFT correspondence is valid in the Coulomb branch, the potential between waves on a pair of test branes in the bulk should be reproduced by the relevant Yang-Mills theory effective action on the boundary. Earlier work has provided evidence for this in the case of constant gauge field brane waves. In this paper we provide concrete evidence for an earlier proposal that the effects of e...

The action of isoprenaline, a purely beta-agonist, was investigated on frog atrial fibres under voltage clamp conditions; tonic tension was induced by long depolarizing pulses and the outward delayed current simultaneously developed. The cumulative dose-response curves showed that isoprenaline increased the peak of tonic tension in the concentration range 10(-8) to 3. 10(-6) mol.l-1, with a max...

A method for the purification of polynucleotide phosphorylase from Escherichia coli has been developed. The purified enzyme has a specific activity 700-fold higher than the crude extract. When enzyme fractions obtained at different stages of the purification were assayed by phosphorolysis of polyadenylic acid (poly A) or 32P-orthophosphate exchange with the S’diphosphates of adenosine, uridine,...