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Showing papers by "University of Barcelona published in 1980"


Journal ArticleDOI
TL;DR: In this paper, the development of mylonite microstructures and fabrics are discussed from this point of view and seven possible softening processes are discussed: superplasticity, geometrical softening, continual recrystallization, reaction softening and chemical softening.

708 citations


Journal ArticleDOI
25 Dec 1980-Nature
TL;DR: On the basis of their primary structure, the lysine-rich histones are a unified family of proteins that are protected from trypsin digestion in chromatin and corresponds to the segment of highest sequence conservation.
Abstract: On the basis of their primary structure, the lysine-rich histones are a unified family of proteins. Each has an amino acid chain which falls into three distinct domains. Only the central domain (approximately 80 residues) is in a folded conformation. It is protected from trypsin digestion in chromatin and corresponds to the segment of highest sequence conservation. Without the flanking domains it is able to close two full turns of DNA in the nucleosome and can thus locate the H1 molecule.

623 citations


Journal ArticleDOI
TL;DR: The degree of stimulation of the renin-angiotensin-aldosterone system in cirrhosis is related to abnormalities in the hepatic hemodynamics, and a close direct correlation was observed between the wedged hepatic vein pressure and plasma renin concentration and activity.

236 citations


Journal ArticleDOI
TL;DR: In this article, the contraction of the description of Brownian motion from phase space to position space is discussed by means of non-Markovian Langevin equations in position space.
Abstract: The contraction of the description of Brownian motion from phase space to position space is discussed by means of non-Markovian Langevin equations in position space. A Fokker-Planck equation valid for any time is derived for the harmonic oscillator, and the overdamped, critical, and infradamped cases are discussed. For anharmonic potentials systematic corrections to the Smoluchowski equation are derived. Such corrections can be interpreted in this context as an expansion in powers of the correlation time of the “colored” stochastic noise appearing in the Langevin equation. The breakdown of the Fokker-Planck approximation is also discussed.

109 citations



Journal ArticleDOI
01 Jul 1980-Chest
TL;DR: A unique case of severe and diffuse endocardial fibroelastosis covering the entire left ventricle and associated with pseudoxanthoma elasticum is presented.

55 citations


Journal ArticleDOI
TL;DR: Weinberg's renormalization scheme, although more cumbersome from the computational point of view, has a more immediate physical interpretation than 't Hooft's minimal renormalisation scheme and is expected to lead to smaller higher-order coefficients in a perturbative approach to QCD.

51 citations


Journal ArticleDOI
TL;DR: In this article, Langevin equations with external non-white noise are considered and a Fokker Planck equation valid in general in first order of the correlation timeτ of the noise is derived.
Abstract: Langevin equations with external non-white noise are considered. A Fokker Planck equation valid in general in first order of the correlation timeτ of the noise is derived. In some cases its validity can be extended to any value ofτ. The effect of a finiteτ in the nonequilibrium phase transitions induced by the noise is analyzed, by means of such Fokker Planck equation, in general, for the Verhulst equation under two different kind of fluctuations, and for a genetic model. It is shown that new transitions can appear and that the threshold value of the parameter can be changed.

47 citations


Journal ArticleDOI
TL;DR: Periarterial muscle resection should be considered in symptomatic patients with this rare anomaly after surgical excision of myocardial bridges.

46 citations


Journal ArticleDOI
TL;DR: Improper intervals are shown to mean “control-band-like variables’, in contrast to the classical “autonomous random variables” represented by proper intervals.
Abstract: The SIGLA System has been designed to obtain an Interval Computing System working with the whole surrounding structure of the standard interval setI (R) (see [9]), that is, the lattice completion ofI (R) with the ordinary algebraic operations extended onto it. A statistical component associating intervals to Bounded Fuzzy Distributions is added. Rounding semantics onI* (R) is considered, and bounding theorems directing programming are given. Improper intervals are shown to mean “control-band-like variables”, in contrast to the classical “autonomous random variables” represented by proper intervals. An outline of the SIGLA language is given.

46 citations


Journal ArticleDOI
TL;DR: A review of advances in the synthesis of morphan compounds from 1980 to the present day can be found in this paper, where the authors highlight advances in morphan synthesis from carbocyclic compounds.
Abstract: This review highlights advances in the synthesis of morphan compoundsfrom 1980 to the present day. 1 Introduction 2 Synthetic Approaches from Carbocyclic Compounds 2.1 Aminocyclization Processes Forming the C(1)-NBond 2.1.1 From Amino Alkenes 2.1.2 From Amino Ketones 2.1.3 By Amine Alkylation 2.1.4 By Amino Conjugate Addition upon Enones 2.2 Aminocyclization Processes Forming the N-C(3)Bond 2.3 Cyclization Processes Forming the C(3)-C(4) Bond 2.4 Cyclization Processes Forming the C(4)-C(5) Bond 2.4.1 Aldol Reactions 2.4.2 Piperidine Ring Closure by a Heck Reaction 2.4.3 Alkenylation of Enolates 2.4.4 Radical Cyclizations 2.4.5 Miscellaneous Approaches 3 Synthetic Approaches from Piperidine Derivatives 3.1 Cyclization upon Iminium Ions Forming the C(1)-C(8) Bond 3.2 Cyclization Processes Forming the C(5)-C(6) Bond 3.3 Cyclization Processes Forming the C(6)-C(7) Bond 4 Cascade Processes 5 Rearrangements 6 Synthesis of 5-Phenylmorphans 7 Conclusions

Journal ArticleDOI
TL;DR: In this paper, the existence of transversal homoclinic points in the collinear three-body problem, restricted and general, and in the planar circular restricted three body problem was proved.

Journal ArticleDOI
TL;DR: Callus cultures have been established from mesocotyl tissues taken from immature embryos of one experimental hybrid homozygous fl 2 and Regeneration of Complete plants from these calluses was accomplished by a subculture of the callus on a medium containing 0.25 mg 2,4-D and NAA.

Journal ArticleDOI
TL;DR: The differential effect of vanadate on the two types of phosphoglycerate mutases supplies a novel way to easily differentiate both types of enzymes, and may contribute to the clarification of the mechanism of action of the 2,3-bisphosphoglycerates independent phosphoglycersite mutases.

Journal ArticleDOI
TL;DR: In the eastern Pyrenees mylonite belts are related to a late phase of Hercynian folding leading to the development of an open antiform-tight synform large-scale structure.

Journal ArticleDOI
TL;DR: In this paper, formaldehyde condensation catalyzed by the conjugate bases of thiazolium ions, leads to a complex mixture of unbranched aldoses and ketoses, in which glucose, galactose, glyceraldehyde dimer, xylose and arabinose have been identified.

Journal ArticleDOI
TL;DR: The average values of the hematological parameters show a tendency to be high due to the greater metabolic rate of the passeriform group, and a parallel may be made between altitude adaptation for hypoxia and high oxygen requirements for activity.

Journal ArticleDOI
TL;DR: The Fokker-Planck approximation for n -dimensional nonmarkovian Langevin equations is discussed in this article through an expansion in powers of the correlation time of the noise and an application to brownian motion is presented.

Journal ArticleDOI
TL;DR: It appears now definitely established that HMG-CoA reductase can undergo a phosphorylation-dephosphorylation cycle, in vitro, as a possible mechanism of modulation of its activity, in vivo.

Journal ArticleDOI
TL;DR: The possible implications of the enzymes studied upon the ammonia-producing activity of rat Placenta are discussed together with the relative decreasing role of placenta for the overall metabolic activity of the foetus, especially during the last phases of its development.
Abstract: Aspartate transaminase, alanine transaminase, glutamate dehydrogenase, arginase, serine dehydratase, tyrosine transaminase, glutamine synthetase, glutaminase and adenylate deaminase activities were measured in crude homogenates of 12, 19 and 21-day rat placentae. There is a considerable quantitative importance in enzymes able to produce free ammonia, such as adenylate deaminase and glutamate dehydrogenase, activity that progressively decrease with the age of placenta. The glutamine synthetase and tyrosine transaminase activities increase with age, while serine dehydratase decreases considerably and aspartate and alanine transaminase do not change practically. Arginase shows a maximum at 19, with lower 12 and 21-day activities. No measurable glutaminase activity has been found. The possible implications of the enzymes studied upon the ammonia-producing activity of rat placenta are discussed together with the relative decreasing role of placenta for the overall metabolic activity of the foetus, especially during the last phases of its development.

Journal ArticleDOI
TL;DR: The effect of mild stress on various plasma metabolites in the rat has been studied and indicates that minimal stress can have major effects upon the composition of blood, and suggest the need for strict precautions on the handling of animals during blood sampling.
Abstract: The effect of mild stress on various plasma metabolites in the rat has been studied. Mild stress resulted in significant decreases in liver size and glycogen content, as well as in an increase of blood glucose. In addition, plasma lactate, insulin, glycerol and urea, as well as a number of amino acids were altered by stress. These data indicate that minimal stress can have major effects upon the composition of blood, and suggest the need for strict precautions on the handling of animals during blood sampling. The site of blood extraction — tail tip vs. neck — was also found to have a significant effect on plasma lactate, glucose and urea concentrations. In stressed animals the differences between tail- and neck blood composition were increased.

Journal ArticleDOI
TL;DR: When given orally to patients who had been bleeding from acute lesions but were not doing so at the beginning of treatment, cimetidine with antacid is more effective than antacids alone in the prevention of further bleeding.
Abstract: The hemostatic effect of cimetidine has been investigated in a double-blind, randomized trial in patients bleeding from acute mucosal lesions. During a 48-hr period, hemostasis was achieved in 5 of 15 patients (33%) treated with intravenous cimetidine administered with antacid therapy and in four of 12 patients (33%) treated with antacids alone. In a second stage of the trial, the effect of oral cimetidine in preventing further bleeding was investigated. Bleeding did not recur in 18 patients receiving cimetidine and antacids while 6 out of 20 patients who were given antacids alone suffered further hemorrhage during the 14-day period of the study. It is concluded that intravenous cimetidine administered with antacids was not found more effective in obtaining hemostasis than antacids alone. When given orally to patients who had been bleeding from acute lesions but were not doing so at the beginning of treatment, cimetidine with antacids is more effective than antacids alone in the prevention of further bleeding.

Journal ArticleDOI
TL;DR: The amount aflatoxins synthesized by the toxicogenic strains decreased gradually after succesive subculturing, and was accompanied by marked morphological changes.
Abstract: Two strains of Aspergillus flavus Link ex Fr. and two strains of A. parasiticus Speare were cultured on crushed moist wheat (Triticum durum var. Pane no. 257) for aflatoxin production studies in correlation with morphological changes. The toxicogenic strains were adapted to the substratum by means of successive transfers at regular intervals (72 h.) The amount aflatoxins synthesized by the toxicogenic strains decreased gradually after succesive subculturing. The decrease was accompanied by marked morphological changes. One of the strains studied, A. flavus NRRL 3251, lost completely the capacity of aflatoxin synthesis after several subcultures, presenting at the same time strong morphological variations. A. flavus CBS 120.62 also lost its toxicogenicity after six subcultures.

Journal ArticleDOI
TL;DR: In this article, the role of π 0 and ϱ exchange together with additional correlations in the direct part of the Δ-hole interaction was investigated and it was shown that the influence of ΀ 0 propagation in the elastic channel is considerably reduced, unlike the situation in pion scattering.

Journal ArticleDOI
TL;DR: In this paper, a necessary and sufficient condition in terms of integrals along invariant manifolds is found for the rectilinear case for the triple collision manifold of McGehee.
Abstract: We consider the regularization by continuity w.r.t. initial conditions (geometric or Easton method) which has a sense both in physical and computational aspects. Using the idea of triple collision manifold of McGehee we study the values of masses for which the invariant manifolds of equilibrium points coincide. Local analytical equations are continuated numerically. So one gets the masses satisfying a necessary condition. Again analytically we discuss the neighbourhood of t.c.m. at the equilibrium points. A necessary and sufficient condition in terms of integrals along invariant manifolds is found for the rectilinear case. This can be tested for the masses obtained above. Only a countable (symmetric) set of masses remains. Then, due to errors in physical measurements or numerical integrations we can never expect a regular behaviour. Extension to the planar case is also taken into account.

Journal ArticleDOI
TL;DR: It is unlikely that there is cross-reactivity between colophony and calcium lignosulfonate and it is considered that the case described is one contact allergy to calcium ligntic acid.
Abstract: of abietic acid shows no correlation to the lignine monomer (Fig. 1). \Ve have performed epicutaneous tests on four persons with a known history of contact allergy to colophony and none of these reacted to Wahfolin. We therefore conclude that it is unlikely that there is cross-reactivity between colophony and calcium lignosulfonate and consider that the case described is one contact allergy to calcium lignosulfonate.

Journal ArticleDOI
TL;DR: The search for foam cells in the urinary sediment of patients with possible renal xanthogranulomatosis can constitute a harmless and useful diagnostic method for this frequently occurring renal disease.

Journal ArticleDOI
TL;DR: The hematological and anatomical values are discussed in relation to the peculiar flight habits of this apodiform group.

Journal ArticleDOI
TL;DR: The rather unusual H1-type histone phi 1 from sea urchin sperm thus has a three-domain structure like calf thymus H1 and chicken erythrocyte H5 and is not merely a free-solution artefact.
Abstract: The lysine-rich H1-type histone phi 1 from the sperm of the sea urchin Arbacia lixula has been subjected to tryptic digestion in free solution at high ionic strength. Tw trypsin-resistant peptides G phi 1 and LG phi 1 have been isolated, comprising 81 and 95 amino acids respectively, i.e. about a third of the intact histone. Circular dichroism and 270-MHz proton NMR have been used to demonstrate that the smaller peptide G phi 1 contains all the secondary and tertiary structure of intact histone phi 1. It is concluded that the resistant peptides represent a compact folded portion of the histone phi 1 chain, whilst the remaining two-thirds is disordered in free solution. Trypsin digestion of Arbacia lixula nuclei, under conditions where histone phi 1 remains tightly bound to the chromatin, leads to the same resistant peptide G phi 1. From this it is concluded that in chromatin the chain region corresponding to G phi 1 is likewise folded and inaccessible to trypsin, whilst the remaining exposed residues are located periferally and probably in an extended conformation. The rather unusual H1-type histone phi 1 from sea urchin sperm thus has a three-domain structure like calf thymus H1 and chicken erythrocyte H5. The present data emphasise the fact that this three-domain structure exists in chromatin and is not merely a free-solution artefact.