We investigated whether highly purified preparations of basal (fetal-facing) membrane isolated from normal term human placentas possess Na(+)-H+ exchanger activity. Uptake of Na+ into basal membrane vesicles was stimulated many-fold by an outwardly directed H+ gradient. This H(+)-gradient-dependent uptake was inhibitable by amiloride and its analogues. Na+ uptake in these vesicles did not occur...

Calcium ions play a critical role in neurotransmitter release. The cytosolic Ca2+ concentration ([Ca2+]cyt) at nerve terminals must therefore be carefully controlled. Several different mechanisms, including a plasmalemmal Na/Ca exchanger, are involved in regulating [Ca2+]cyt. We employed immunofluorescence microscopy with polyclonal antiserum raised against dog cardiac sarcolemmal Na/Ca exchang...

A shell and tube heat exchanger is a class of heat exchanger designs seen most common type of heat exchanger in oil refineries and other large chemical processes, and is suited for higher-pressure applications. As its name implies, this type of heat exchanger consists of a shell (a large pressure vessel) with a bundle of tubes inside it. One fluid runs through the tubes, and another fluid flows...

The deterioration of the performance of a cross flow heat exchanger with condensation due to the longitudinal conduction was investigated. For a relatively small change of wall temperature along the flow directions which was shown to be common in many applications, the energy equations were solved numerically. An iterative method was used to solve the resulting equations of the finite differenc...

A cDNA clone encoding a rabbit ileal villus cell Na+/H+ exchanger was isolated and its complete nucleotide sequence was determined. The cDNA is 4 kb long and contains 322 bp of 5'-untranslated region, 2451 bp of open reading frame and 1163 bp of 3'-untranslated area, with 70%, 91% and 40% identity to the human sequence, respectively. Amino acid sequence deduced from the longest open reading fra...

To evaluate the influence of the sodium/proton exchanger (Na+,H+ exchanger) on the constriction of rat resistance vessels and on the iliac artery, the isometric vasoconstrictions of renal resistance vessels and strips from iliac artery derived from Wistar-Kyoto rats were measured using a vessel myograph. The Na+,H+ exchanger was activated by intracellular acidification using propionic acid. Cyt...

in this paper the effect of block shape vortex generators (vgs) on an air-water fin-tube heat exchanger has been studied experimentally using exergy analysis method. also the effect of these vgs on increasing heat transfer rate has been simulated numerically and the results show a good agreement with the experiments. in this research we used a wind tunnel to produce wind flow over heat exchange...

the purpos of this paper is to aim the maximum heat transfer rate in a plate-fin heat exchanger with a constant volume and a contant surface area at a prescribed pressure drop. this paper propose a method for design a plat-fin heat exchanger in which a maximum pressure drop occurs at a constant volume and surface are. in this paper as a case study, a preheater of a gas turbine which is a plate-...

This study presents an innovative and simple way to increase the rate of heat transfer in a spiral plate heat exchanger model. Several circular cross-section rods, as continuous vortex generators, have been inserted within the spiral plate heat exchanger in the cross-stream plane. The vortex generators are located at various azimuth angles of α=30◦, 60◦, 90◦, and 120◦ with non-dimensional diame...

Customarily, the LMTD correction factor, FT, is used to screen alternative designs for a heat exchanger. Designs with unacceptably low FT values are discarded. In this paper, authors have proposed a more fundamental criterion, based on feasibility of a multipass exchanger as the only criteria, followed by economic optimization. This criterion, coupled with asymptotic energy targets, provide the...