It was found that when a mixture of hydrogen and oxygen in the fuel gas stream is injected, either gasoline or diesel, it increases its combustion efficiency decreasing at the same time the pollutant ...emissions of fuels without burning into the atmosphere and saving from 10 up to 30% on fuel. In order to obtain this gaseous mixture, reactors oxyhydrogen operating in conditions in which the engine operates has been developed. A part important of these reactors are the electrodes that should count with characteristics as high resistance to the corrosion, high electronic conductivity and high surface area. This work presents the construction of electrodes for oxyhydrogen reactors with different characteristics, allowing to increase life time while maintaining the efficiency of the reactors. For this electroless nickel plating method was select to deposit a thick coating on aluminum and brass substrates at different bath times. Structural and morphological characterization is presented and discussed. The results obtained by X-ray diffraction and optical microscopy, showed that both materials to favor the deposition of nickel. It can be concluded that the time of deposition of 4, 6 and 8 hours not significantly influences the amount of nickel deposited on the material in reference with X-ray analysis.
The exchange of substances between higher organisms and the environment takes place across epithelia consisting of one or more cell layers. To perform this function, epithelial cells have two basic ...differentiated properties: 1) they form tight junctions (TJs) that seal the extracellular space, and 2) they are polarized into an apical and a basolateral domain, with entirely different structural, biochemical and physiological properties. Our understanding of the mechanisms involved in the expression of these properties has been greatly enhanced by the availability of epithelial cell lines that form TJs and polarize in vitro under conditions suitable for experimental control. In this article we summarize our studies on the synthesis and polarized expression of ion channels in epithelial cells. MDCK cells have four types of K+ channels in the apical domain, and a fifth one in the basolateral domain. The basolateral side also has a population of CI- channels. Each type of channel is absolutely polarized. Harvesting with trypsin-EDTA reduces the area of the plasma membrane by 50% and the channel population by 90%. Upon plating, these channels are recovered within a few hours. We describe here the main extracellular and intracellular mechanisms involved in these phenomena.
A case of a 30 year-old patient is presented with infertility, 56 days opsomenorrhea, cervical tenderness, left adnexial mass, beta subunit of Human Gonadotrophin Corionic (HGC) of 112 mUl/mL, ...endovaginal ultrasonogram showed trophoblastic vascular flow with cardiac output, suggestive of ectopic gestation. Laparoscopy confirmed the diagnostic of left ectopic interstitial pregnancy, salpingocentesis was done with Methotrexate and potassium chloride and severe endometriosis was found. The postoperative control with seric levels of beta subunit HGC were negativized at 28 days. The treatment lasted 4 months with Nafarelin. The second look Hysteroscopy-Laparoscopy showed complete resolution of ectopic gestation, endometriosis improvement and bilateral tubal permeability.
We present the results of a search for variable stars in the globular cluster NGC 5286, which has recently been suggested to be associated with the Canis Major dwarf spheroidal galaxy. 57 variable ...stars were detected, only 19 of which had previously been known. Among our detections one finds 52 RR Lyrae (22 RRc and 30 RRab), 4 LPV's, and 1 type II Cepheid of the BL Herculis type. Periods are derived for all of the RR Lyrae as well as the Cepheid, and BV light curves are provided for all the variables. The mean period of the RRab variables is = 0.656 days, and the number fraction of RRc stars is N(c)/N(RR) = 0.42, both consistent with an Oosterhoff II (OoII) type -- thus making NGC 5286 one of the most metal-rich (Fe/H = -1.67; Harris 1996) OoII globulars known to date. The minimum period of the \RRab's, namely Pab,min = 0.513 d, while still consistent with an OoII classification, falls towards the short end of the observed Pab,min distribution for OoII globular clusters. As was recently found in the case of the prototypical OoII globular cluster M15 (NGC 7078), the distribution of stars in the Bailey diagram does not strictly conform to the previously reported locus for OoII stars. We provide Fourier decomposition parameters for all of the RR Lyrae stars detected in our survey, and discuss the physical parameters derived therefrom. The values derived for the RRc's are not consistent with those typically found for OoII clusters, which may be due to the cluster's relatively high metallicity -- the latter being confirmed by our Fourier analysis of the ab-type RR Lyrae light curves. We derive for the cluster a revised distance modulus of (m-M)V = 16.04 mag. (ABRIDGED)
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