Showing papers by "Autonomous University of Barcelona published in 1983"
TL;DR: In this paper, the results obtained in both iso-and non-iso-thermal experiments have been successfully interpreted with the same set of kinetic parameters with the best fit to their experimental data has been obtained in the case of the Johnson-Mehl-Avrami-Erofe'ev equation, with values of the kinetic exponent dependent only on composition.
Abstract: Calorimetric studies of chalogenide alloy glasses, (GeSe2)60(GeTe)40 − x(Sb2Te3)x obtained by water quenching at room temperature, have been performed by isothermal and continuous heating in a Perkin-Elmer DSC-2 calorimeter. The samples show a simple peaked crystallization exotherm when x = 0, 10 and two stage crystallization for x = 20. The results obtained in both iso- and non-iso-thermal experiments have been successfully interpreted with the same set of kinetic parameters. Among the several kinetic models which we analysed, the best fit to our experimental data has been obtained in the case of the Johnson-Mehl-Avrami-Erofe'ev equation, with values of the kinetic exponent dependent only on composition. The effective activation energy decreases slowly from E = (229 ± 6)kJ/mol at x = 0 to E = (184 ± 5)kJ/mol at x = 20 (first crystallization peak).
133 citations
TL;DR: Correlation analysis performed with field data resulted in significant, but low, correlation coefficients, consistent with laboratory data showing that brown Chlorobiaceae were dominant in deep layers in meromictic lakes, whereas green Ch chlorobiaceae dominated in layers nearer the surface or underneath plates of Chromatiaceae.
Abstract: Accurate studies of the pigment composition and isolation in pure cultures of Chlorobiaceae from samples of eight Spanish lakes show that there are two main coexisting groups of green and brown Chlorobium spp. represented respectively by Chlorobium limicola and Chlorobium phaeobacteroides. Laboratory experiments with pure and mixed cultures of the isolated strains show that light quality plays a selective role on the species composition among Chlorobiaceae. This selection depends on the pigment composition which determines the in vivo absorption spectrum of the cells as well as on their ability to adjust the intracellular concentration of light-harvesting pigments to the spectral distribution and energy of light. Correlation analysis performed with field data resulted in significant, but low, correlation coefficients. Nevertheless, they were consistent with laboratory data showing that brown Chlorobiaceae were dominant in deep layers in meromictic lakes, whereas green Chlorobiaceae dominated in layers nearer the surface or underneath plates of Chromatiaceae. The combination of laboratory and field observations stress the role of biological light filtering in determining the species composition among Chlorobiaceae in lakes.
130 citations
TL;DR: The prognosis of desynapsis is discussed, based on 41 cases studied, and the results obtained in semen samples as compared with previous results are reevaluate.
Abstract: Meiotic studies have been carried out in a series of 1100 infertile and sterile males. Of these, 599 cases have been studies in testicular biopsy, and 501, in semen samples. This is the largest meiotic series published so far. The incidence of meiotic anomalies was 4.3%. The most frequent chromosome abnormality was desynapsis (3.7%). However, the number of cases with a meiotic arest, usually due (73.9%) to synaptic anomalies in prophase I, was much higher (18.4%). An attempt is made to correlate the incidence of meiotic anomalies with the results of semen analysis. We discuss the prognosis of desynapsis, based on 41 cases studied, and reevaluate the results obtained in semen samples as compared with our previous results.
122 citations
TL;DR: In this paper, a source of CP violation in supersymmetric theories is discussed, and the effect of such violations on the electric dipole moment of the electron and the neutron is estimated.
113 citations
TL;DR: The method is applied to the study of conformational changes of three well-characterized proteins: melittin from bee venom, cytochrome c from horse heart and bacteriorhodopsin from Halobacterium halobium and the results obtained are found to be in accordance with the known conformational properties of these proteins.
Abstract: Fourth-derivative spectrophotometry is applied to the analysis of solvent effects on the spectral transitions of N-acetyl-l-tryptophan amide, as well as of its mixtures with N-acetyl-l-tyrosine ethyl ester. These compounds were analyzed in different media. It was found that the position of the longest-wavelength minimum of the fourth-derivative spectrum is mainly determined by the nature of the Trp environment, with a minor contribution from that of Tyr. A geometrical parameter is also defined, which depends on both Trp and Tyr environments. The simultaneous consideration of both parameters allows an estimation to be made of the Trp environment. The method is applied to the study of conformational changes of three well-characterized proteins: melittin from bee venom, cytochrome c from horse heart and bacteriorhodopsin from Halobacterium halobium. The results obtained are found to be in accordance with the known conformational properties of these proteins. In addition, the fourth-derivative operation completely eliminates the interference from the near-ultraviolet bands of the prosthetic groups.
50 citations
TL;DR: In this article, a general expression for the two-photon form factor of neutral pseudoscalar mesons is given in a quark triangle model, which is in agreement with other calculations based on vector meson dominance, giving a new example of Q2 duality.
49 citations
TL;DR: In this article, plane-symmetric cosmological solutions to Einstein's equations which can be generated by the "soliton" technique, using the homogeneous Bianchi solutions as seeds and arbitrary numbers of real or complex poles.
Abstract: We examine plane-symmetric cosmological solutions to Einstein's equations which can be generated by the "soliton" technique, using the homogeneous Bianchi solutions as seeds and arbitrary numbers of real or complex poles. In some circumstances, these solutions can be interpreted as "incipient" gravitational waves on the Bianchi background. At early times they look like nonlinear inhomogeneities propagating at nearly the speed of light ("gravisolitons"), while at late times they look like cosmological gravitational waves.
46 citations
TL;DR: An unusual case of the multicentric type of angiofollicular lymph node hyperplasia is described, which furthermore showed an excellent response to low dosis radiotherapy and became asymptomatic.
Abstract: Angiofollicular lymph node hyperplasia is a disease of unknown etiology in which two distinct histologic forms are recognized: the hyalin vascular and the plasma-cell types. Up to the current time only a few multicentric cases have been described. The authors describe an unusual case of the multicentric type, which furthermore showed an excellent response to low dosis radiotherapy. Complete, lasting remission was induced and the patient became asymptomatic.
42 citations
42 citations
TL;DR: The effect of housing conditions and the presence of a conspecific on corticoadrenal response to a novel environment was studied in male Sprague-Dawley rats, indicating that rats exhibit greater emotional reactivity in situations which combine familiar and novel elements than those completely unfamiliar.
42 citations
TL;DR: In this article, the equivalence between vector meson dominance and quark models is clearly established (Q2 duality), and the relevant mass scales in that decay imply some universal properties for the amplitude.
TL;DR: In this paper, it was shown that the ATP increase produced in the first 20 min is dependent on RecBC exonuclease activity and it must be due to substrate level phosphorylation since an uncoupler such as dinitrophenol does not affect it.
TL;DR: In this paper, the electron density and the molecular electrostatic potential of β-carbolines were studied using ab initioSTO-3G wave functions using a previous model built with monoamine oxidase substrates and irreversible inhibitors.
Abstract: The electron density and the molecular electrostatic potential of the β-carbolines are studied using ab initioSTO-3G wave functions. The analysis was done from the point of view of a previous model built with monoamine oxidase substrates and irreversible inhibitors. The results confirm the usefulness of the model and make it possible to propose new precision to the molecular electrostatic potential patterns needed to have monoamine oxidase inhibitory activity.
TL;DR: The results reproduce efficiently the experimental classification and enable us to predict the type of enzymatic action of molecules not yet experimentally classified.
Abstract: Similarities and differences between mitochondrial monoamine oxidase (MAO) substrates and inhibitors (both A and B types) are considered, studying quantitatively two molecular properties: electron density and molecular electrostatic potential (MEP). The following molecules are considered: substrates: PHEA, BZA, tele-N-methyl-histamine, phenylethanolamine, phenylpropylamine, tryptamine, dopamine, phenoxylethylamine, noradrenaline, serotonin, and p-nitro-phenylethanolamine; inhibitors: Deprenil, Clorgyline, and Lilly 51641 (only the moiety involved in the A–B differentiation is considered). The wave functions needed to calculate the analyzed properties are of ab initio quality, and have been calculated in analogous conformations, all near the energetic minima. Electron densities distributions are qualitatively compared by means of a correlation coefficient defined over the whole space. Otherwise, patterns of the possible zones of electrostatic interactions are described by means of the distances and angles between minima, in order to differentiate MAO-A and MAO-B substrates. The results reproduce efficiently the experimental classification and enable us to predict the type of enzymatic action of molecules not yet experimentally classified.
TL;DR: The reactivity of the title compounds with different nucleophiles has been checked and it was shown that products from reaction with sodium phenylthiolate result from an elimination-addition process in which protoanemonin is the key intermediate.
TL;DR: In this paper, a non-local constitutive equation for the heat flux was compared with microscopic equations used for the analysis of second sound in solids, leading to the possibility of a turbulent phonon flow under some specific physical conditions.
Abstract: Heat and electric conduction in a rigid solid is investigated in the framework of extended irreversible thermodynamics. This allows us to apply directly the original procedure of Onsager to the analysis of the reciprocal relations. A non-local constitutive equation for the heat flux previously obtained is compared with microscopic equations used for the analysis of second sound in solids. A hydrodynamical analogy of this equation leads to the possibility of a turbulent phonon flow under some specific physical conditions.
TL;DR: It suggests that rats experienced more emotional reactivity in presence of a familiar animal than in presenceof a non-familiar one, suggesting competition between social investigation and novel environment exploration.
Abstract: The effect of the presence either of a familiar or non-familiar conspecific animal on serum corticosterone and some behavioral responses in the open field was studied in male Sprague-Dawley rats. Animals tested in presence of a familiar animal showed a higher corticosterone response and a higher defecation rate. It suggests that rats experienced more emotional reactivity in presence of a familiar animal than in presence of a non-familiar one. Time spent in social interaction was higher in non-familiar pairs; however, ambulation and rearing were lower, suggesting competition between social investigation and novel environment exploration.
TL;DR: The host ultrastructure changed as a result of epibiontic attachment, showing symptoms of cellular degradation.
Abstract: Epibiontic cells on the surface of the photosynthetic purple sulfur bacteriumChromatium minus, collected several times during the year from 3 different Spanish lakes, were examined using scanning and transmission electron microscopy. The cells attached to theC. minus cell wall by an electron-dense pad, but did not enter the cell. They were ovoidal (about 0.6Μm wide) when free, and slightly curved rods (0.3×0.6Μm) when undergoing division. Division only occurred when cells remained attached toChromatium. A septum was formed, resulting in 2 or 3 curved rods surrounded by a common capsule. Detached daughter cells became ovoidal.
TL;DR: In the strains studied, thein vitro activity of ciprofloxacin is superior to that of temocillin against theEnterobacteriaceae and to the that of ceftazidime against theP.
Abstract: We studied thein vitro activity of ciprofloxacin against 570 strains of ampicillin-resistantEnterobacteriaceae and 286Pseudomonas aeruginosa strains. 95.26% of theEnterobacteriaceae and 53.45% of theP. aeruginosa were inhibited by 0.1 mg/l of ciprofloxacin. 2 mg/l of ciprofloxacin inhibited all of theEnterobacteriaceae strains and 4 mg/l all of theP. aeruginosa. We compared the activity of ciprofloxacin with that of temocillin in theEnterobacteriaceae strains. In theP. aeruginosa strains, classified according to their susceptibility to carbenicillin and gentamicin, we compared the activity of ciprofloxacin with that of ceftazidime. In the strains studied, thein vitro activity of ciprofloxacin is superior to that of temocillin against theEnterobacteriaceae and to that of ceftazidime against theP. aeruginosa strains.
TL;DR: The pigments and biomass of anoxygenic phototrophic bacteria were measured during a year cycle in Lake Cisó (Girona, Spain) and two genera, Chromatium and Chlorobium, accounted for most of the bacterial population.
Abstract: The pigments and biomass of anoxygenic phototrophic bacteria were measured during a year cycle in Lake Ciso (Girona, Spain). Two genera, Chromatium and Chlorobium, accounted for most of the bacterial population. The bacteria were present throughout the year despite complete mixing of the lake during fall and winter. This was possible because the sulfide production in the sediment was high enough to make the lake anaerobic to the very surface. Solar radiation, temperature, and biomass of Chromatium sp. were found to be important in determining pigment concentrations by correlation analysis. Sulfide concentration and biomass of Chlorobium spp. were found to be unimportant. A path analysis was performed to determine what percentage of the variability of pigments could be explained by the variables studied. Since a high percentage could be explained, it was possible to conclude that solar radiation, temperature, and biomass of Chromatium sp. were the main variables.
TL;DR: The C‐banding patterns show both a high degree of polymorphism as well as the presence of terminal and interstitial C‐bands in the karyotypes of Lagothrix lagothricha cana, Cebus apella and Cebus capucinus.
Abstract: We describe the C-bands in the karyotypes of Lagothrix lagothricha cana, Cebus apella and Cebus capucinus The C-banding patterns show both a high degree of polymorphism as well as the presence of terminal and interstitial C-bands Varying amounts of heterochromatin result in dimorphism of some chromosome pairs The high incidence of chromosome rearrangements found in the Cebidae may be due to the presence of terminal and interstitial C-bands
TL;DR: In this paper, the authors investigate the CP violation effects in supersymmetry broken models, due to the exchange of new fermions (gauginos and higgsinos), and show that the real part of the K 0 − K 0 amplitude is too small to account for the ϵ parameter.
TL;DR: Casein kinase 1 phosphorylated human fibrinogen, in a reaction that did not use GTP as phosphoryl donor and was neither stimulated by cyclic AMP or Ca2+, nor inhibited by the cyclicAMP-dependent protein kinase inhibitor protein.
TL;DR: The authors define brevemente el regimen feudal de propiedad de las aguas and justificar el significado del neologismo despatrimonializacion, que me he tomado la libertad de acunar.
Abstract: El objetivo de la presente comunicacion consiste en precisar los diversos modos en que el agua, recurso economico fundamental, resulto afectada por el proceso de modernizacion que implicaba la labor revolucionaria antifeudal del siglo xix y las consecuencias que de ello se derivaron. Para conseguir esta meta sera necesario definir brevemente el regimen feudal de propiedad de las aguas y justificar el significado del neologismo despatrimonializacion, que me he tomado la libertad de acunar. Trazo general de las soluciones que dio la revolucion liberal a los problemas de las formas de propiedad tipicas del antiguo regimen es su caracter negativo, es decir, la eliminacion de los factores que la hacian inmovilizada, amortizada o.vinculada. Como la tierra, tampoco las aguas tenian, en la etapa de predominio del sistema feudal, la condicion de bienes libres de propiedad particular. El mencionado caracter negativo esta en la base, incluso en su misma construccion gramatical, de los terminos castellanos desamortizacion y desvinculacion. Esta es una de las razones por las que me he decidido a emplear, en el caso del agua, el termino despatrimonializacion. He elegido tambien, y principalmente, esta expresion porque integra muy bien, en su parte positiva, las distintas situaciones que se dan respecto de la propiedad del agua en la sociedad feudal.
TL;DR: The consumption of various groups of antihypertensive drugs in Spain during the period 1977–1981 has been measured by the DDD method and wide qualitative differences between countries were identified.
Abstract: The consumption of various groups of antihypertensive drugs in Spain during the period 1977–1981 has been measured by the DDD method. The total consumption of the drugs did not change much during this time. Combinations of thiazides with other hypotensives accounted for more than half the total antihypertensive drugs used. The consumption of rauwolfia and its derivatives, and of dihydralazine, was higher than of β-blockers and methyldopa. Total consumption of antihypertensives in 1981 was 37.5 DDDs/1 000 inhab/day, which was much lower than in Denmark (136.6 DDDs/1 000 inhab/day), Finland (114.5), Iceland (92.2), Norway (89.4) and Sweden (138.7). Wide qualitative differences between countries were also identified. Although other factors may play a role, it is suggested that these striking differences may be due to differences in general health policy and in the pharmaceutical markets.
TL;DR: In this article, a cutoff dependent upper bound on the gravitino mass of O(106−109) GeV is provided. But the upper bound assumes that the supersymmetry violations in the particle spectrum are governed by a tree-level mass, which should therefore be heavier than O(20 GeV.
TL;DR: In this paper, the effect of correlation energy on the mechanism of the butadiene + ethylene reaction has been studied by means of Moller-Plesset perturbation theory.
TL;DR: A causal link between administration of amiodarone and pulmonary fibrosis is suggested, and the present data tend to indicate a hypersensitivity mechanism.
Abstract: Of 25 cases of idiopathic pulmonary fibrosis, confirmed by open chest lung biopsy between January 1979 and July 1981, 5 patients had been taking amiodarone in doses less than 600 mg daily for 1 to 6 years. No lung disease had been observed in any patient before the administration of amiodarone, and other drugs, factors and diseases thought to play a role in the causation of pulmonary fibrosis were ruled out. Two patients died of respiratory insufficiency, and only 1 does not now suffer from serious sequelae. Review of a further 5 cases reported in the literature and the present data suggest a causal link between administration of amiodarone and pulmonary fibrosis, and tend to indicate a hypersensitivity mechanism.