Thermophysical and volumetric study of mixtures {p-cymene¿+¿propan-1-ol} at several temperatures and atmospheric pressure. Modeling with COSMO-RS

Experimental isobaric molar heat capacities at atmospheric pressure have been determined for the mixture {p-cymene + propan-1-ol} every 10 K in the temperature interval (298.8–328.5) K and over the entire composition range with a Calvet type calorimeter. Densities, necessary for calculating heat capacities, have been also measured in similar conditions. Excess molar volumes have been calculated from densities. They are positive at (318.15 and 328.15) K and sigmoidal at (298.15 and 308.15) K with negative values in the zone very rich in propan-1-ol. Excess molar heat capacities have been calculated from the molar heat capacities and show positive values. Both excess molar properties increase as the temperature rises at a given molar fraction. Excess properties are discussed in terms of intermolecular interactions. The solvation model COSMO-RS has been applied to predict the excess molar heat capacities, being the quantitative predictions rather poor

Solubility of gases in fluoroorganic alcohols. Part III. Solubilities of several non-polar gases in water¿+¿1, 1, 1, 3, 3, 3-hexafluoropropan-2-ol at 298.15¿K and 101.33¿kPa

Solubilities of the non-polar gases H2, N2, O2, CH4, C2H6, C2H4, CF4, SF6, and CO2 in the mixture (water + 1, 1, 1, 3, 3, 3-hexafluoropropan-2-ol) at the temperature of 298.15 K and 101.33 kPa partial pressure of gas are reported. A polynomial dependence of the solubilities on the molar fraction of the binary liquid mixture is found. The Henry''s constants at the vapor pressure of water, the standard changes in the Gibbs energy for the solution process and for the solvation process, and the so-called excess Henry''s constant are calculated. The results have been compared with those obtained by Scaled Particle Theory (SPT). A method to compare the solubility of a gas in different liquids is proposed and applied to 2, 2, 2-trifluoroethanol and 1, 1, 1, 3, 3, 3-hexafluoropropan-2-ol

Solubilities of gases in cycloethers. The solubility of 13 nonpolar gases in 2, 5-dimethyltetrahydrofuran at 273.15 to 303.15¿K and 101.32¿kPa

The solubilities of gases in liquids are interesting, not only from a practical point of view, but also because they provide a rigorous touchstone to test the structural models on the liquid state. In this work the solubilities of 13 nonpolar gases, He, Ne, Ar, Kr, Xe, H2, D2, N2, CH4, C2H4, C2H6, CF4, and SF6, in 2, 5-dimethyltetrahydrofuran at five temperatures between (273.15 and 303.15) K and 101.32 kPa partial pressure of gas were measured and the associated thermodynamic functions were calculated. Correlation of data has been made and the capacity of prediction of several typical molecular models of liquids, namely, SPT model, perturbation theory, UNIFAC and COSMO-RS, specifically applied to gas solubilities, has been checked

Trasplante hepático

Liver transplantation is an efficient therapeutic option for terminal hepatic diseases. The principal indications of liver transplantation are hepatic cirrhosis, hepatic tumours (mainly, hepotocellular carcinoma) and acute liver failure. Over the years, the absolute contraindications for a transplant have lessened. Surgical techniques have also undergone changes. The results of liver transplant have improved so that survival one year after the transplant is close to 90% and after five years some 80% of transplanted patients continue to live

Molar heat capacities of the mixture {1, 8-cineole + ethanol} at several temperatures and atmospheric pressure

Molar heat capacities at atmospheric pressure have been determined every 5 K for the mixture {1, 8-cineole (1) + ethanol (2)} in the temperature interval (304.7 to 324.5) K and the whole composition range with a Calvet type calorimeter Setaram C80. From the molar heat capacities, excess molar heat capacities have been calculated, their values being positive and increasing as the temperature rises. The solvation model COSMO-RS has been applied to predict the excess molar heat capacities. The model overestimates the values of the excess heat capacities but predicts well the trend of variation of the excess molar heat capacity with the temperature

Oxidation of CO and methanol on Pd-Ni catalysts supported on different chemically-treated carbon nanofibers

In this work, palladium-nickel nanoparticles supported on carbon nanofibers were synthesized, with metal contents close to 25 wt % and Pd:Ni atomic ratios near to 1:2. These catalysts were previously studied in order to determine their activity toward the oxygen reduction reaction. Before the deposition of metals, the carbon nanofibers were chemically treated in order to generateoxygen and nitrogen groups on their surface. Transmission electron microscopy analysis (TEM) images revealed particle diameters between 3 and 4 nm, overcoming the sizes observed for thenanoparticles supported on carbon black (catalyst Pd-Ni CB 1:2). From the CO oxidation at different temperatures, the activation energy Eact for this reaction was determined. These values indicated a high tolerance of the catalysts toward the CO poisoning, especially in the case of the catalystssupported on the non-chemically treated carbon nanofibers. On the other hand, apparent activation energy Eap for the methanol oxidation was also determined finding—as a rate determining step—the COads diffusion to the OHads for the catalysts supported on carbon nanofibers. The results here presented showed that the surface functional groups only play a role in the obtaining of lower particlesizes, which is an important factor in the obtaining of low CO oxidation activation energies

Optimization of the catalytic layer for alkaline fuel cells based on fumatech membranes and ionomer

Polymer electrolyte fuel cells with alkaline anion exchange membranes (AAEMs) have gained increasing attention because of the faster reaction kinetics associated with the alkaline environment compared to acidic media. While the development of anion exchange polymer membranes is increasing, the catalytic layer structure and composition of electrodes is of paramount importance to maximize fuel cell performance. In this work, we examine the preparation procedures for electrodes by catalyst-coated substrate to be used with a well-known commercial AAEM, Fumasep® FAA-3, and a commercial ionomer of the same nature (Fumion), both from Fumatech GmbH. The anion exchange procedure, the ionomer concentration in the catalytic layer and also the effect of membrane thickness, are investigated as they are very relevant parameters conditioning the cell behavior. The best power density was achieved upon ion exchange of the ionomer by submerging the electrodes in KCl (isopropyl alcohol/water solution) for at least one hour, two exchange steps, followed by treatment in KOH for 30 min. The optimum ionomer (Fumion) concentration was found to be close to 50 wt%, with a relatively narrow interval of functioning ionomer percentages. These results provide a practical guide for electrode preparation in AAEM-based fuel cell research

Quality of care of patients with type-2 diabetes in Galicia (NW Spain) [OBTEDIGA project]

[Abstract] Aims:  The aim of this study was to describe the degree of compliance of agreed practices with reference to primary care patients with Type 2 diabetes of 40 years old and older in Galicia (NW Spain). Methods:  A total of 108 primary care physicians were selected at random from the totality of doctors. Each physician selected 30 patients at random from their patients suffering from diabetes of 40 years old or older. External observers gathered information from each patient’s medical record regarding their characteristics, condition and degree of compliance of selected indicators of good practice. Results:  Group of physicians participated in this study had a mean age of 50 years (standard deviation = 3.9); 48% of them were females; and 17.5% involved in medical residents training. A total of 3078 diabetic patients were included in the study: mean age = 69 years (SD = 10.9), 47.6% women, presence of high blood pressure (72%), hypercholesterolaemia (56%), and regular smokers (10.3%). Compliance with selected indicators such as foot examination (14%), ophthalmological examination (30.6%), abdominal circumference measurement (6.1%), measurement of total or LDL-cholesterol (78.1), blood pressure measurement (84.8), glycosylated haemoglobin measurement < 7% (54.3%) was observed. Adequate monitoring in cases of high blood pressure and hypercholesterolaemia were 34.2% and 27.4%, respectively. Variability between physicians differs according to the different indicators, with interquartile range for compliance of between 16.4 and 66%. Conclusions:  There is a wide margin for improvement in the adaptation of clinical practice to recommendations for diabetic patients. The large variation existing in certain indicators would suggest that certain control objectives are less demanding than advisable in those that comply least, while low compliance and low variability in other indicators point to structural problems or unsatisfactory training of doctors