Showing papers by "Free University of Berlin published in 1972"
TL;DR: In this article, the problem of a nematic liquid crystal in an electric field is solved, and numerical solutions for various values of parameters are given for various parameters of the liquid.
Abstract: The problem of a nematic liquid crystal in an electric field is solved. Effects due to conductivity of the liquid have been neglected. Numerical solutions are given for various values of parameters. The solution is compared with experimental data taken from the literature. A computer program has been developed to do a non-linear least-squares fit of experimental data with the solution given in the present paper.
247 citations
TL;DR: In this article, the current density i+ of platinum oxide layer formation was measured in dependence on potential e, time t and coverage ϑ or the equivalent layer thickness under potentiostatic conditions in 0.5 M H2SO4.
143 citations
TL;DR: The results point to a participation of 5-HT and dopamine in the central mediation of antinociceptive drug effects.
143 citations
TL;DR: In this article, the formation and reduction of platinum oxide layers in 0.5 M H2SO4 was investigated by galvanostatic pulse measurements, and the results led to the conclusion that the properties of the layer are dependent on the formation conditions of layer, i.e. the formation rate, the ageing of layer and the method of the setting of the coverage (anodic/increase or cathodic/decrease).
134 citations
TL;DR: In the first part of this work matrix cells were examined by [3H]TdR autoradiography in rat embryos from the twelfth to the eighteenth day of gestation and it was shown that the matrix cell layer comprises at least two different cell populations with different generation times.
124 citations
TL;DR: The results suggest a possibly special effect of DPH on the development of the calcium and bone disorders that have been observed in patients treated with anticonvulsant drugs.
Abstract: SUMMARY
In vitamin D deficient rats the influence of diphenylhydantoin (DPH) and phenobarbital (PB) pretreatment on intestinal uptake of 45calcium and on the activity of CaBP was studied. The DPH rats show in contrast to the PB and control rats a significantly reduced intestinal uptake of 45calcium. However, the activity of CaBP was similar in all investigated groups. These results suggest a possibly special effect of DPH on the development of the calcium and bone disorders that have been observed in patients treated with anticonvulsant drugs.
RESUME
On a etudie chez des rats qui manquaient de vitamine D, l'effet d'un pre-traitement avec de la diphenylhydantoine (DPH) et du phenobarbital (PB) sur l'absorption intestinale de calcium 45 et sur l'activite du CaPB.
Les rats qui avaient du DPH, en opposition aux rats de controle et aux rats avec PB, avaient une absorption intestinale de calcium 45 significativement reduite.
L'activite du CaPB etait cependant semblable chez tous les groupes. Ces resultats suggerent un effet possible particulier de la DPH sur l'origine des troubles du calcium et du metabolisme des os, qui ont ete observes chez des patients en traitement avec des produits anticonvulsivants.
94 citations
TL;DR: The results suggest a role of the adrenergic system in orthostatic renin release, but the functional connection between renal haemodynamics, tubular sodium handling and reninrelease across orthostasis cannot fully be explained on the basis of the present knowledge of renin releasing mechanisms.
Abstract: 1. In eight normal subjects, ten patients with labile hypertension, six with advanced essential hypertension and six with renovascular hypertension, plasma renin concentration, cardiac output, mean arterial pressure, clearances of creatinine and p -aminohippurate (PAH), and sodium excretion were measured before and after 30 min of 45° upright tilting. Changes in plasma adrenaline and noradrenaline concentration were measured in addition in the normal subjects, and in plasma volume in normal subjects and patients with labile essential hypertension. 2. In patients with advanced essential hypertension, heart rate and calculated peripheral resistance increased significantly less than in normal subjects, and plasma renin increased by 15% in this group, in comparison to 37% in normal subjects, 48% in labile essential hypertension, and 57% in renovascular hypertension. There was a positive relationship between changes in renin and noradrenaline concentrations in normal subjects. 3. Apart from a negative correlation between the increases in plasma renin concentration and mean arterial pressure in patients with renovascular hypertension, there were no significant relationships between changes in plasma renin and haemodynamics. 4. A negative correlation between changes in plasma renin and filtration fraction and a positive relationship between changes in renin and sodium excretion were found in normal subjects and patients with labile hypertension. Plasma renin increase was directly related to changes in the tubular rejection fraction of sodium in patients with labile hypertension. In the same group there was a negative correlation between changes of sodium rejection fraction and filtration fraction. 5. The results suggest a role of the adrenergic system in orthostatic renin release, but the functional connection between renal haemodynamics, tubular sodium handling and renin release across orthostasis cannot fully be explained on the basis of our present knowledge of renin releasing mechanisms.
72 citations
TL;DR: It seems that this inward transport of vapour by hydrated larvae becomes ineffective below a relative humidity of 85%.
68 citations
TL;DR: Spironolactone, canrenone, and potassium canrenoate can be analyzed in the low nanogram range utilizing a fluorescence reaction in sulfuric acid, specific for 17-alkyl-17-hydroxy-4,6-dien-3-one steroids.
56 citations
TL;DR: In this article, normal product techniques are applied to the study of gauge invariance in a massive vector-meson model in renormalized perturbation theory, and composite fields are defined which are invariant under a one-parameter family of covariant gauge transformations.
Abstract: Normal-product techniques are applied to the study of gauge invariance in a massive-vector-meson model in renormalized perturbation theory. Composite fields are defined which are invariant under a one-parameter family of covariant gauge transformations. Ward identities are derived for Green's functions involving an arbitrary number of vector and axialvector currents. The lack of lowest-order radiative corrections to the triangle anomaly of the axial-vector Ward identity is verified using Bogoliubov-Parasiuk-Hepp-Zimmermann methods.
55 citations
TL;DR: Comparisons of the two methods demonstrated the suitability of scanning microscopy for the 3-dimensional desription of surfaces of biological materials in the lateral ventricles of the cat.
01 Jan 1972
TL;DR: The stratosphere over the Southern Hemisphere was known only locally and mainly in its lowest levels until satellite measurements of radiance became a reality as discussed by the authors, and necessity limits us to deal with the lower half of the stratosphere, below 10 mb.
Abstract: The stratosphere over the Southern Hemisphere was known only locally and mainly in its lowest levels until satellite measurements of radiance became a reality. As we are using these recent data in addition to midseason, monthly mean maps for 1969 as principal means of description, much of our material is unlikely to be representative of long-term conditions, and our conclusions cannot always be so firm as we may seem to express them. In addition, necessity limits us to deal chiefly with the lower half of the stratosphere, below 10 mb. We have tried, however, to ease these severe restrictions by referring as often as possible to the better known Northern Hemisphere for analogy and contrast. Some aspects of the mean state of the stratosphere below 100 mb have been dealt with in Chapters 3–5.
TL;DR: In this paper, a system of Z protons and 4 N neutrons (Z + N = even) moving in non-degenerate j-levels is treated for an isoscalar T = 1 pairing interaction and an effective four-body force.
TL;DR: In this paper, a time-differential perturbed angular distribution experiment on the 247-keV level of a metal was conducted, excited by the ($d,p$) reaction in the metal.
Abstract: A time-differential perturbed angular distribution experiment on the 247-keV level of $^{111}\mathrm{Cd}$, excited by the ($d,p$) reaction in $^{110}\mathrm{Cd}$ metal, shows a static quadrupole interaction at high temperatures and pronounced effects of radiation damage at lower temperatures.
TL;DR: Indirect evidence indicates that rising metabolite levels under these circumstances may lead to a displacement of unchanged sulphonamide from protein binding sites, which is related to the degree of renal impairment.
Abstract: The pharmacokinetics of sulphamethoxazole (SMZ) and trimethoprim (TMP) have been investigated in four healthy volunteers, 15 patients with stable chronic renal failure and 3 patients on regular dialysis. The dosage schedule was 400 mg of SMZ and 80 mg of TMP orally every 12 h. The plasma concentrations and urinary excretion have been analysed in terms of a one compartment open model, allowing for elimination by renal excretion and metabolic processes. — At equilibrium the plasma concentrations of unchanged sulphonamide showed no significant correlation with the degree of renal impairment. The accumulation of TMP increased slightly without affecting the concentration ratio of both agents in plasma. In contrast, increasing accumulation of metabolized SMZ was demonstrated in the presence of renal insufficiency. Indirect evidence indicates that rising metabolite levels under these circumstances may lead to a displacement of unchanged sulphonamide from protein binding sites. — The cumulative urinary excretion amounted to 82.4% of the dose of sulphonamide administered, which probably corresponds to the fraction of the compound absorbed. The urinary concentration of biologically active SMZ was slightly below the plasma level, especially in advanced renal failure, but it remained above the minimum inhibitory concentrations reported in the literature. The concentration of TMP in urine was considerably higher than in plasma, it decreased with loss of renal function as did active SMZ.
TL;DR: In this article, cross sections for the reactions 12C(p, 2p) and 16O(p 2p ) were calculated in the framework of a model which takes explicit account of nucleon-nucleon correlations and of the decay of the residual nucleus by particle emission.
TL;DR: In this article, the electric field gradients due to the crystalline field have been found to be 200 times larger than those predicted from point charge calculations, which can be explained by an enhanced conduction electron density at the interstitial sites and an increase of the Sternheimer factor γ∞ in the metallic environment.
Abstract: Estimates of the electric field gradient in heavy rare earth metals have been evaluated from experimental hyperfine interaction data. In addition, the magnetic hyperfine fields are analyzed. In the metals the effective radial integrals 〈r−3〉4f of the magnetic and quadrupole hyperfine interaction are reduced at most by 10% compared with the free ion values. The electric field gradients due to the crystalline field have been found to be 200 times larger than those predicted from point charge calculations. This antishielding effect can be explained by an enhanced conduction electron density at the interstitial sites and an increase of the Sternheimer factor γ∞ in the metallic environment.
TL;DR: In this paper, it was shown that the main contribution to the observed splittings of organic nitroxide radicals comes from the unpaired π-electron, which was rationalized by a population analysis of the nitrogen bonds.
TL;DR: In this article, the T-band and Q-band ESR in EuxLa1−x Al2 and GdxLa 1−x al2 has been measured at T band and Q band frequencies as a function of concentration x and temperature, and the bottleneck can be broken, and a g-shift can be obtained for Eu2+ (Δg = + 0.05) and Gd3+ (γ = 0.10).
TL;DR: The experimental data are believed to indicate a meaningful integration of visual and vestibular signals in the primary visual cortex.
Abstract: Publisher Summary Psychophysical and neurophysiological experiments about the interaction of visual and vestibular signals in the central nervous system are described in this chapter. A steady visual input (after-image) moves in an otherwise dark visual field perpendicularly as the vestibular receptors are stimulated sinusoidally. The subjective vertical of a human observer, placed in different constant positions in space depends also on the spatial orientation of a striated visual pattern. Microelectrode recordings from single neurons of the primary visual cortex of enckphale isolk cats are used to investigate the interaction of vestibular and visual signals. Single neurons in the primary visual cortex responded to labyrinth d.c.-polarization either with an on-, off- or on-off activation. The activation is strongest during the first second of labyrinth stimulation. The neuronal response to light stimuli is increased by simultaneous polarization of the labyrinth. In some cortical neurons, however, besides an increase of the instantaneous impulse frequency during the light induced excitatory periods also a prolongation of the latency or of the inhibition periods occurred. Hence, the gross electrical stimulus of the labyrinth receptors did not elicit a simple general increase of cortical neuronal activity. The experimental data are believed to indicate a meaningful integration of visual and vestibular signals in the primary visual cortex.
TL;DR: A substance which inhibits the biological activity of the vegetalizing inducing factor has been found in the high-speed supernatant of chick embryo homogenates and is a macromolecule found inthe glycoprotein fraction.
TL;DR: In this paper, it was shown that ≤ is a well-quasi-ordering for all finite graphs with at most n disjoint circuits and that all graphs not contractible into a V5− (the complete graph V5 minus one edge) are well quasi-ordered by ≤.
TL;DR: The data obtained in humans and animals demonstrate that epileptic drugs do not interfere with the intestinal uptake of the vitamin and that previously reported alterations in the metabolism of cholecalciferol during anticonvulsant therapy were probably due to enhanced hydroxylation of vitamin D in the liver rather than to a diminished body pool of Vitamin D.
Abstract: SUMMARY
The intestinal absorption of radioactive cholecalciferol was studied in patients who had been treated for years with anticonvulsant drugs and in pheno-barbital-treated rats. The aim of the study was to elucidate whether or not the bone changes in patients could be caused by a decreased uptake of vitamin D. The data obtained in humans and animals demonstrate that epileptic drugs do not interfere with the intestinal uptake of the vitamin. Previously reported alterations in the metabolism of cholecalciferol during anticonvulsant therapy were therefore probably due to enhanced hydroxylation of vitamin D in the liver rather than to a diminished body pool of vitamin D.
RESUME
Chez les malades traites pendant plusieurs annees par des medicaments anti-epileptiques et chez des rats traites par phenobarbital, on a etudie l'absorption intestinale de cholecacilferol radioactif.
Ce travail avait pour but de savoir si les alterations osseuses des patients pouvaient etre causees par une diminution d'absorption de la vitamine D.
Les resultats observes chez l'homme et chez l'animal demontrent que les drogues anti-epileptiques n'interferent pas avec l'absorption intestinale de la vitamine.
Les modifications du metabolisme du cholecalciferol qui ont ete rapportees dans la litterature, au cours du traitement anti-epileptique, etaient donc probablement dues a une augmentation de l'hydroxylation de la vitamine D dans le foie plutot qu'a une diminution de la quantite de vitamine D dans le corps.
TL;DR: In this paper, a simple approximation is discussed, in which the off-shell effect is attributed mainly to a momentum dependence expressed by penetration factors, and a new and sensitive method for the determination of resonance angular momenta l.
TL;DR: In this paper, the doublyodd nuclei 64 Cu and 66 Cu are investigated by means of γ-ray spectroscopy following 63,65 Cu(d, p) with pulsed 6.5 MeV deuterons.
TL;DR: In a series of experiments in rats it was possible to prove that δ8-THC has the same type of effectiveness as the stereo-isomeric δ9-THCs and there was no difference in hexobarbital elimination between rats treated with THC in a single dose or over a 10-day period and control animals.
Abstract: In a series of experiments in rats it was possible to prove that δ8-THC has the same type of effectiveness as the stereo-isomeric δ9-THC.
TL;DR: The economic theory of German neoliberalism comprises a certain conglomerate of an absolutely free choice of selecting an economic system on the one hand and a definite determination of the economic policy that results of this choice on the other; this conglomerate prevented the theory of neoliberalism to become a valid theory of economic policy.
Abstract: SUMMARY
The Economic Theory of German neoliberalism comprises a certain conglomerate of an absolutely free choice of selecting an economic system on the one hand and a definite determination of the economic policy that results of this choice on the other; this conglomerate prevented the theory of neoliberalism to become a valid theory of economic policy. The former German neoliberalism reduces the categories of aims and means to the choice of the economic system, an unhistorical approach, because such a choice never happened at all. But such an approach enabled the neoliberal authors to reduce any economic policy to only conservate the market system. Even the modern approach of separating qualitative and quantitative policies pursues the same intentions: although indefensible positions vanished under the impression of Keynesian theories, nevertheless the definition of a genuine qualitative policy implicates that the latter has the function of conservating the market system. This distinction of qualitative and quantitative policy has another meaning than in the system of Tinbergen. Since the criteria of separation are ambiguous, even the modern approaches of German neoliberal economic policies remain inadequate compared with the modern theory of economic policy a la Tinbergen.
01 Jun 1972
TL;DR: Isolated yolk platelets, nuclei and pigment granules, ribosomes and the ribosome-free supernatant of homogenates from whole gastrulae of Xenopus laevis were tested for their inducing properties.
Abstract: Isolated yolk platelets, nuclei and pigment granules, ribosomes and the ribosome-free supernatant of homogenates from whole gastrulae ofXenopus laevis were tested for their inducing properties.The subcellular fractions were obtained by differential centrifugation in sucrose media and their purity was checked by electronmicroscopy.The microsomal fraction shows archencephalic and deuterencephalic inducing capacity which is enhanced after extraction with pyrophosphate and with phenol. The membrane structures of this fraction can partially be separated from the ribosomes by treatment with desoxycholate. Proteins with deuterencephalic and spinocaudal inducing activity are extractable from the desoxycholate treated microsomal fraction with 1 M NH4Cl.The supernatant, free of ribosomes, has a rather weak inducing ability. After extraction with phenol the archencephalic and deuterencephalic activity increases, but not the spinoaudal.Isolated nuclei induce small deuterencephalic structures and a relatively high percentage of spinocaudal differentiations. Extraction with phenol does not enhance the rate of these inductions.The yolk platelets show mainly deuterencephalic inducing activity which is associated essentially with the superficial layer of these particles. Proteins, inducing archencephalic and deuterencephalic tissue differentiations, are extractable in small amounts from the platelets after partial removal of the superficial layer.
TL;DR: The present results provide additional evidence for the hypothesis that the decrease in radiosensitivity of stage-7 oocytes in the RO I population is not due to a shift in the germ-cell stages sampled, and indicate a restriction of the decreased radiosensitivity to one or a few germ- cell stage(s).
Abstract: • An irradiated (RO I) and a contemporaneous control (+60) population (both of which originally were derived from the Berlin wild stock of Drosophila melanogaster) were tested for possible differences in radiosensitivity. Prior to the commencement of the present studies, the irradiated population had been exposed to 2100 R of X-rays each generation for over 220 generations in an experimental design which involved the sampling of oocytestages 6–14, mature spermatozoa and spermatids in each generation. • The data show that in none of the germ-cell stages tested (stage-14 oocytes, nurse cells of stages-4–6 oocytes, spermatozoa and spermatids) was there any evidence for a lower radiosensitivity of RO I with any of the measured end-points of radiation damage. These results stand in contrast to those from the earlier tests on stage-7 oocytes sampled from the same populations, in which a markedly decreased radiosensitivity of the RO I population had been observed. They thus indicate a restriction of the decrease in radiosensitivity to one or a few germ-cell stage(s). • The present results provide additional evidence for the hypothesis (advanced in the earlier study) that the decrease in radiosensitivity of stage-7 oocytes in the RO I population is not due to a shift in the germ-cell stages sampled.
01 Jun 1972
TL;DR: In this article, die vorliegende Arbeit befast sich mit dem Induktionsvermogen isolierter Dotterplattchen, der Kerne und Pigmentgranula, der Ribosomen und des ribosomenfreien Uberstandes aus Ganzkeimhomogenaten der Gastrula von Xenopus laevis.
Abstract: Die vorliegende Arbeit befast sich mit dem Induktionsvermogen isolierter Dotterplattchen, der Kerne und Pigmentgranula, der Ribosomen und des ribosomenfreien Uberstandes aus Ganzkeimhomogenaten der Gastrula vonXenopus laevis.