Showing papers by "Katholieke Universiteit Leuven published in 1969"
TL;DR: It was found that adrenaline specifically increases the amplitude and duration of the plateau phase of the cardiac action potential of cow Purkinje fibers, and the simplest explanation for the observed phenomena can be found in an increase of Ca++ inward current under the influence of adrenaline.
Abstract: Conduction block in heart cells by K+ rich, or Na+ depleted solutions can be overcome by adrenaline. In order to explain this phenomenon, the effect of adrenaline on the membrane resting and action potentials of cow Purkinje fibers was measured at various extracellular concentrations of Na+, K+ and Ca++, in the presence of tetrodotoxin, Mn++ and beta-receptor antagonists.
268 citations
TL;DR: The effect of pressure on the temperature-dependent association of β-casein was studied by the method of light scattering as discussed by the authors, which indicated an increase in partial specific volume of the protein with association.
Abstract: The effect of pressure on the temperature-dependent association of β-casein was studied by the method of light scattering. Between 1 and 1500 kg/cm2, β-casein is reversibly depolymerized, indicating an increase in partial specific volume of the protein with association. Possible mechanisms for association are discussed. At still higher pressures reversible reassociation is observed, which is ascribed to conformational changes in the β-casein molecule.
100 citations
TL;DR: It is proposed that these cells are involved at pulmonary level in the production of both amines and the kinin-generating system, interfering with various pulmonary areas such as the circulatory adaptation (or failure) of the newborn at birth and pulmonary oncology (carcinoid and oat cell tumors).
87 citations
TL;DR: Blood flow in the tibialis anterior muscle was measured using the 133 Xe local clearance technique in hypertensive and normal male subjects of different ages, at rest, and after maximum ischemic exercise recumbent, sitting and standing, indicating that both muscle flow and resistance are increased compared to the normal group.
62 citations
TL;DR: In this article, a study of 216 active and retired hemp workers and 285 control subjects in and near Callosa de Segura, Spain, was conducted to diagnose byssinosis, grade 3, rather than unspecified chronic bronchitis in these older workers.
50 citations
TL;DR: In this paper, the velocity of ultrasonic pulses in liquid argon along seven isotherms at temperatures ranging from 100 K to 150 K and pressures up to 500 atm was measured.
39 citations
TL;DR: The activation and the inactivation of the phosphorylase phosphatase, were shown to be dependent on time, temperature and the concentration of ATP and Mg ions.
Abstract: When a partially purified dog liver phosphorylase phosphatase preparation was incubated with ATP and Mg ions, its activity increased several fold. A slower activation was observed in the presence of Mg ions only. When the same preparation was preincubated with ATP alone, complete inactivation was obtained. The ATP pretreated enzyme could then be reactivated by Mg++, as well as by ATP and Mg++. The activation and the inactivation of the phosphorylase phosphatase, were shown to be dependent on time, temperature and the concentration of ATP and Mg ions. Neither on the activation nor on the inactivation of the phosphorylase phosphatase could and effect of cyclic 3′ :5′ -AMP be observed.
39 citations
TL;DR: Four cases of congenital dyserythropoietic anaemia in two families are described and the suggestion made that the hyperbilirubinaemia of the unconjugated type is mainly due to intramedullary bilirubin formation.
Abstract: Summary.
Four cases of congenital dyserythropoietic anaemia in two families are described. The evidence for a dyserythropoietic state is discussed and the suggestion made that the hyperbilirubinaemia of the unconjugated type is mainly due to intramedullary bilirubin formation. Many abnormal multinucleated erythroblasts were found in the bone marrow. The evidence for a membrane defect and a possible haemoglobin abnormality have been presented.
28 citations
TL;DR: In this article, the potential energy curves for the first three excited states of the uranyl ion were calculated using the positions of distinct continua, observed by Pringsheim in the ultraviolet part of the absorption spectrum.
21 citations
TL;DR: In this paper, the authors performed tensile tests on homogenized single crystals of Mg-Sn alloys at room temperature and found that the increase in critical resolved shear stress can be partially explained by short range order (sro).
20 citations
TL;DR: In this paper, single crystals of lead with either thallium, indium, bismuth, cadmium, mercury or antimony were tested in tension in liquid air.
Abstract: Single crystals of lead with either thallium, indium, bismuth, cadmium, mercury or antimony were tested in tension in liquid air. The critical resolved shear stress τ0 increases linearly with increasing solute content c in a limited concentration range. The increase Δτ0/ΔC is lowest for lead-thallium and highest for lead-antimony. When log Δτ0/ΔC is plotted against log (sf + elf) where sf*[(d1)Pb − (d1)sol/(d1)Pb]10Pb, d1 being the closest distance of approach, and elf = ΣEn, ΣEn being the sum of the electronegativities of solvent and solute, a straight line of slope 2 results. A similar result is obtained with data from the literature for single crystals of copper alloys and of magnesium alloys. However in these cases a different size factor has to be used.
TL;DR: In liver parenchymal cells in experimental and human cholestasis a continuity could be demonstrated between the cell membrane and the membrane of “autophagic vacuoles”.
Abstract: In liver parenchymal cells in experimental and human cholestasis a continuity could be demonstrated between the cell membrane and the membrane of “autophagic vacuoles”. The enzyme activities of Alk. P-ase, ATP-ase, and IDP-ase were associated with the segregation of portions of cytoplasm and organelles presumably in connection with membrane movements but probably also coupled with hydrolytic prosesses.
TL;DR: The intracellular K+, Cl− and Na+ concentrations in the vas deferens cells of the guinea-pig have been estimated from the total ion content, the sorbitol space and the dry wt/wet wt ratio to give a resting potential of −30 mV.
Abstract: The intracellular K+, Cl− and Na+ concentrations in the vas deferens cells of the guinea-pig have been estimated from the total ion content, the sorbitol space and the dry wt/wet wt ratio. The exchange of K+, Cl− and Na+ was studied by following the uptake and the efflux of these ions with radioactive isotopes. The following steady state flux values have been calculated;mK, 2.8 p-moles x cm−2 x sec−1;mCl, 13.2 p-moles x cm−2 x sec−1 andmNa, 7.4 p-moles x cm−2 x sec−1. The values for the permeability constants calculated by the constant field assumptions from the ion fluxes are forPK 8.9×10−8 cm/sec;PCl 9.7×10−8 cm/sec and forPNa 2.1×10−8 cm/sec. The introduction of these values and of the concentrations in the Goldman equation give a resting potential of −30 mV. This value is only half of the value of the measured resting potential. One of the possible explanations for the discrepancy between the measured resting potential and the calculated one is that the resting potential of these smooth muscle cells is partly a diffusion potential and partly due to the operation of an electrogenic sodium pump.
TL;DR: In this article, exact calculations of the capacitance of linearly graded Si p-n junctions, taking the influence of electrons and holes into account, were made, and the results agree well with the experimental data for gradients of less than 1022cm−4.
Abstract: Exact calculations are made of the capacitance of linearly graded Si p-n junctions, taking the influence of electrons and holes into account. The results agree well with the experimental data for gradients of less than 1022cm−4. The discrepancies for gradients larger than 1022cm−4 are probably due an interface-state mechanism.
TL;DR: Diazoreagents bearing a non-ionised activating group have been applied to the study of fœtal bile pigments and it could be demonstrated that at 30-34 weeks of gestation heavily rhesus-immunised human foetuses could form bile Pigments which yielded azobilirubin derivatives more hydrophylic than azobilIRubin.
TL;DR: A method is described permitting computer calculation of a two target trajectory with “centre of arc=target” stereotaxic equipment.
Abstract: A method is described permitting computer calculation of a two target trajectory with “centre of arc=target” stereotaxic equipment.
Journal Article•
TL;DR: In this paper, the cutoff wavelength of the TMc11 mode is treated as a function of the eccentricity of the elliptical cross-section, and an approximate formula is derived for the function qc11 = f(e) for eccentricities between 0.05 and 0.95.
Abstract: The cutoff wavelength of the TMc11 mode is treated as a function of the eccentricity of the elliptical cross-section. From the exact values calculated on a digital computer, an approximate formula is derived for the function qc11 = f(e) for eccentricities between 0.05 and 0.95. Over this range, the cutoff wavelength is given to an accuracy within 0.14%.
TL;DR: Delaey et al. as discussed by the authors presented a diffraction pattern of a 25, 19 at% copper-aluminium martensite with the stacking sequence ABCBCACAB and AB * Department Metaalkunde, University of Leuven, Belgium.
Abstract: Photo.1 Electron diffraction pattern of a 25, 19 at% copper-aluminium martensite with the stacking sequence ABCBCACAB and AB * Department Metaalkunde , University of Leuven, Belgium. (1) L. Delaey: Z. Metallk., 58 (1967), 388. (2) L. Delaey and H. Warlimont: Z. Metallk., 55 (1965), 437. (3) R. S. Toth and H. Sato: Acta Met., 16 (1968), 413. (4) H. Pops and L. Delaey: Trans. Met. Soc. AIME, 242 (1968), 1849. (5) L. Delaey: to be published. (6) J. Brettschneider and H. Warlimont: Z. Metallk., 59 (1968), 740.
01 Jan 1969
TL;DR: It is found that addition to the diet of suecinylsulfathiazole reduced the effect of Purina rat chow on bile acid turnover by approximately 50 % and concluded that the cholesterol-lowering effect ofPurina chow was independent of the microflora since it also occurred in germfree rats.
Abstract: It has been a rather common observation that serum cholesterol levels of animals fed commercial or practical type diets are lower than those of animals fed purified diets. Although several studies (1, 2) support the hypothesis that the hypocholesterolemic effect of practical type diets could be due to acceleration of the turnover of bile acids, it is not clear whether the intestinal microflora play a role in these phenomena. In the experiments of Portman (3), addition to the diet of suecinylsulfathiazole reduced the effect of Purina rat chow on bile acid turnover by approximately 50 %. On the other hand, Wostmann and Kan (4) concluded that the cholesterol-lowering effect of Purina chow was independent of the microflora since it also occurred in germfree rats.
TL;DR: In this article, the stability and field configuration of the TM11 mode in a circular and elliptical waveguide were investigated. But the authors focused on the stability of the waveguide and the maximum electric field in the longitudinal direction.
Abstract: The letter deals with the stability and field configuration of the TM11 mode in a circular and elliptical waveguide. Some numerical results illustrate the variation of the position and value of the maximum electric field in the longitudinal direction as a function of the eccentncity of the cross-section.
TL;DR: A l'encontre de certaines publications récentes et en appliquant la technique plus classique d'imprègnation nerveuse aux sels d'argent, nous n'avons pas observé la présence de réelles fibres nerveuses dans le placenta humain.
Abstract: A l'encontre de certaines publications recentes et en appliquant la technique plus classique d'impregnation nerveuse aux sels d'argent, nous n'avons pas observe la presence de reelles fibres nerveuses dans le placenta humain. Des lors, le placenta humain devrait toujours etre considere comme un tissu non innerve directement.
TL;DR: Les divergences sont fondamentales, and on ne peut esperer un rapprochement facile des different positions as mentioned in this paper, and on devra proceder paretapes.
Abstract: Dans la litteature exegetique de nos jours, les questions posees par le recit du tombeau vide recoivent les reponses les plus variees.Les divergences sont fondamentales, et on ne peut esperer un rapprochement facile des differentes positions. Si on veut y contribuer, l' on devra proceder paretapes. Et le premier probleme qui se pose me parait celui-ci: le texte de Marc xvi contient-il l'etat le plus primitif ou faut-il recourir aux autres evangiles pour remonter a un stade plus archaique de la tradition du tombeau vide? Certains diront peut-etre que le probleme n'est pas reel et que Marc est evidemment premier, quelle que soit la prehistoire du texte et son caractere historique ou legendaire. Mais le nombre de ceux qui pensent autrement n'est pas negligeable et, des deux cotes, on peut trouver son profit dans le dialogue. D'ailleurs, les textes propres de Matthieu, Luc et Jean, s'ils ne revelent pas de traditions anciennes, apparaitront comme des reflexions redactionnelles et il me semble qu'on aurait tort de negliger totalement cette tradition appelee post-marcienne dans l'etude du texte de Marc.
TL;DR: In this paper, pressure and temperature dependence of the viscosity of liquid argon, liquid oxygen and liquid nitrogen are discussed, starting from theArrhenius equation and theDoolittle free volume equation.
Abstract: The pressure and temperature dependence of the viscosity of liquid argon, liquid oxygen and liquid nitrogen are discussed, starting from theArrhenius equation and theDoolittle free volume equation. The experimental results were obtained by measuring the electrical characteristics of a torsionally vibrating quartz crystal, immersed in the investigated liquid and operated at ultrasonic frequencies.