Showing papers by "University of Ljubljana published in 1983"
TL;DR: Assessment of reproductive data from 4,225 women with breast cancer and 12,307 hospitalized women without breast cancer found that the age of approximately 35 years represents for every birth a critical point; before this age any full‐term pregnancy confers some degree of protection; after this ageany full-term pregnancy appears to be associated with increase in breast cancer risk.
Abstract: In an effort to assess the relative importance of age at first birth, age at subsequent births, and total parity to the occurrence of breast cancer, reproductive data from 4,225 women with breast cancer and 12,307 hospitalized women without breast cancer were analyzed by a multiple logistic regression model. Age at first birth was confirmed to be the most important reproductive risk indicator; it was associated with a 3.5 % increase of relative risk for every year of increase in age at first birth (the 95 % confidence interval of this estimate was 2.3 to 4.7 % increase per year). However, age at any birth after the first was also an independent and statistically significant risk indicator; it was associated with a 0.9% increase of relative risk for every year of increase in age at any (and every) birth (the 95 % confidence interval of this estimate was 0.4 to 1.5 % increase per year). There is evidence that the age of approximately 35 years represents for every birth a critical point; before this age any full-term pregnancy confers some degree of protection; after this age any full-term pregnancy appears to be associated with increase in breast cancer risk. The effect of parity is determined by the age of occurrence of the component pregnancies. While most pregnancies occur under the age of 35, the distribution varies from population to population, and this may account for the differences between populations in whether or not a protective effect is seen for births after the first, and if it is seen, its extent.
213 citations
01 Jun 1983-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: Responses of the leg vibratory receptor neurons of the bugNezara viridula to substrate vibrations were recorded electrophysiologically and analysed and the origins of the low (LFR), middle (MFR) and high frequency receptor neurons (HFR) are discussed.
Abstract: 1.
Responses of the leg vibratory receptor neurons of the bugNezara viridula to substrate vibrations were recorded electrophysiologically and analysed.
2.
The low frequency receptor neurons (LFR) respond in a phase-locked manner in the frequency range below 0.12 kHz. The low frequency receptor neurons of the first type (LFR 1) have been analysed in detail. Receptor neurons of this type respond to the upward movement of the leg in a vibration cycle. Their threshold curves follow the line of equal displacement values above 0.05 kHz of the stimulus carrier frequency (Fig. 1). Increasing displacement brings about an increase in the number of spikes per phase (Fig. 2).
3.
The higher frequency vibratory receptor neurons are of two types. The middle frequency receptor neurons (MFR) show the highest sensitivity to the velocity component of vibration at frequencies around 0.2 kHz (Fig. 1); the high frequency receptor neurons (HFR) are most sensitive to velocity at frequencies between 0.75 and 1 kHz (Fig. 1). In the frequency range below the best velocity sensitivity, the threshold curves of both types of neurons follow the line of equal acceleration values; above the best frequency the curves follow the line of equal displacement values (Fig. 1). The shapes and positions of the response curves of both types depend on the stimulus carrier frequency (Fig. 3). The middle (MFR) and high frequency receptor neurons (HFR) respond with characteristically prolonged responses to applied vibrational stimuli of 0.2 kHz carrier frequency (Figs. 4–6). The phase-locked response pattern is observed in both neuron types in the frequency range up to 0.2 kHz (Figs. 4–6).
4.
The frequency and time characteristics of the femaleNezara viridula calling song (FS 1) are well followed by the middle (MFR) and high frequency receptor neurons (HFR) (Figs. 7, 8), but the low frequency receptor neurons (LFR) follow the lower frequency components of the same female sound emission only at higher displacement values.
5.
The origins of the responses of the low (LFR), middle (MFR) and high frequency receptor neurons (HFR) are discussed. The special response characteristics of the higher frequency receptor neurons, i.e. the middle (MFR) and high frequency (HFR) receptor neurons, at 0.2 kHz stimulus frequency may be due to the resonance of the special flaglike structure of cap cells of the subgenual organ.
70 citations
TL;DR: The surface energy, the surface free energy and the surface entropy of liquid water are calculated from the decrease in the number of hydrogen bonds in the surface layer, estimated on the bash of a simplified aater structure scheme as mentioned in this paper.
59 citations
TL;DR: The results support the view that the ratio between histamine and serotonin release depends on the liberator used and show that this ratio can depend on the concentration of the agent inducing secretion.
Abstract: The effect of substance P and compound 48/80 on histamine and serotonin release from not isolated and isolated mast cells have been compared in experimentsin vitro. The response of not isolated and isolated mast cells were virtually identical. The release of both amines, in response to 48/80 and substance P, was dose-dependent. The percentage of histamine released by 48/80 was significantly higher than the percentage of serotonin, the difference being higher at lower concentrations of compound 48/80 after 15 min of incubation. Substance P also showed a tendency to higher efficiency for histamine than for serotonin release. In contrast to 48/80, the dose-response curves for histamine and serotonin release were parallel. These results support the view that the ratio between histamine and serotonin release depends on the liberator used. They also showed that this ratio can depend on the concentration of the agent inducing secretion. The results indicate that substance P as well as 48/80 act rather selectively as histamine liberators and that there is some difference in releasing properties of 48/80 and substance P.
54 citations
TL;DR: The first patient-based results for a micro computer-based EMG signature-controlled functional electrical stimulation (FES) system, for restoring walker-supported and brace-free primitive walking to complete paraplegics, at the patients own command are presented.
53 citations
TL;DR: It is proved that if a graph bundle with baseB and fibreF satisfies at least one of the conditions: (i) B is of chromatic class 1 andΔ(B) > 0, or (ii) B andF both contain a 1-factor, then its total graphX is ofchrome class 1.
49 citations
TL;DR: Some trace element contents of samples of human milk, mainly colostrum and transitional milk, collected in the Ljubljana area of Yugoslavia, are reported and results are discussed briefly in the light of literature values.
49 citations
TL;DR: In this article, the effective nucleon-nucleon potential is presented in the model with two three-quark clusters, and the potential is nonlocal and nonadiabatic, which strongly depends on the definition of the effective potential and on the choice of the subspace used in the calculation.
34 citations
TL;DR: In this article, the common mushroom Laccaria amethystina was found to accumulate on average about 100 ug/g (dry weight) of arsenic in the fruiting body.
31 citations
TL;DR: In this paper, the authors described transformations of some heterocyclic cyanoamino compounds leading to various heter-cyclic systems.s-Triazolo (1,5-α)azines are obtained either in a direct synthetic approach or via the substituted aminotetrazoles, substituted 3-amino-5-oxo-1,2,4-oxadiazolines, and from N-ethoxycarbonylN′-hetero-thioureas or N-heterohyclic N-hydroxy
Abstract: Transformations of some heterocyclic cyanoamino compounds leading to various heterocyclic systems are described.s-Triazolo (1,5-α)azines are obtained either in a direct synthetic approach or via the substituted aminotetrazoles, substituted 3-amino-5-oxo-1,2,4-oxadiazolines, and fromN-ethoxycarbonylN′-heteroaryl thioureas orN-heteroarylN′-hydroxyguanidine. The cyanoamino group reacts also witho-difunctional benzenes to give the corresponding substituted derivatives of benzimidazole, benzoxazole or benzothiazole.
29 citations
TL;DR: The concentration of the free radicals in muscle tissue mitochondria changes with the phase of muscle contraction and the free radical concentration in isolated mitochondria is influenced by KCN and potassium ferricyanide.
Abstract: 1. 1. The concentration of the free radicals in muscle tissue mitochondria changes with the phase of muscle contraction. 2. 2. Potassium cyanide (KCN) influences the shape of the isotonic tetani mechanograms; the contraction is still strong and qualitatively comparable in amplitude to untreated controls. 3. 3. On the other hand, the correlation between the free radical concentration and muscle contraction is lost. 4. 4. The free radical concentration in isolated mitochondria is influenced by KCN and potassium ferricyanide. 5. 5. The free radical concentration changes due to the electron flow in the respiratory chain. 6. 6. Inhibition of the respiratory phosphorylation by KCN could affect the free radical level.
01 Jul 1983
TL;DR: The bioconversion of waste material remaining after apple brandy distillation was investigated and an Aspergillus niger strain was chosen as the most convenient microorganism for converting waste organic substances into microbial biomass.
Abstract: The bioconversion of waste material remaining after apple brandy distillation was investigated. Different cellulolytic fungi were tested for their ability to convert the waste organic substances into microbial biomass. An Aspergillus niger strain was chosen as the most convenient microorganism. By growing this mold on the apple slop the following results were obtained: filtration time was shortened by 30 times, reduction of the chemical oxygen demand in the liquid phase in the range of 50–80% depending on the substrate dilution and a dry filter cake enriched with fungal biomass to about 12 g/l containing up to 22% raw proteins and certain amounts of cellulolytic enzymes in the filtrate. The influence of the initial pH, the salt addition and the dilution of the substrate were studied as well.
TL;DR: In this paper, the effects of magnetic and electric fields on transport phenomena in dilute polyatomic gases are reviewed within the framework of first order Enskog theory, and the established technique of approximate operator inversion is used to give first order approximations of the transport coefficients.
Abstract: Effects of magnetic and electric fields on transport phenomena in dilute polyatomic gases are reviewed within the framework of first order Enskog theory. The established technique of approximate operator inversion is used to give first order approximations of the transport coefficients. Instead of the customary expansion of polarization into orthogonal polynomials a more general treatment is chosen here so as to accomodate recent experimental observations. The polarizations produced by macroscopic fluxes are assumed to be eigenfunctions of the collision operator within the subspace of functions anisotropic in angular momentum. The formalism is extended to mixtures in a way to let the final expressions assume the same form as for pure gases. The obtained transport coefficients obey several symmetry relations and inequalities. Additional inequalities are now also derived for the matrix describing the saturated field effects.
TL;DR: Involatile molecules usually exhibit a protonated molecular ion MH + in positive and an (M-H − species in negative ion fast atom bombardment mass spectra as mentioned in this paper.
TL;DR: In this article, the temperature dependence of the 17 O NQR spectra of the O-H-O bonded oxygens in PbHPO 4 was studied using a proton 17 O double resonance technique.
TL;DR: In this paper, the synthesis of 4-aminopteridine 3-oxides is described, where the pyrimidine part undergoes transformations with various reagents to give 4-hydroxyaminopteridines, substituted pyrazines, or substituted 1,2,4-oxadiazolyl-pyrazines.
TL;DR: In this article, the frequency and temperature dependence of T 1 and T 1p in the cholesteric and isotropic phases of cholesteryl-oleyl-carbonate (COC) have been determined together with the temperature dependent of the self-diffusion constant D. In the MHz region, the relaxation is dominated by molecular selfdiffusion with D being of the order 10 −12 m 2 /s.
Abstract: The frequency and temperature dependence of T 1 and T 1p in the cholesteric and isotropic phases of cholesteryl-oleyl-carbonate (COC) have been determined together with the temperature dependence of the self-diffusion constant D in the isotropic phase. In the MHz region the relaxation is dominated by molecular self-diffusion ― with D being of the order 10 −12 m 2 /s ― and by local molecular rotations with τ c ∼2×10 −10 s at T=24°C. In the kHz region, on the other hand, order director fluctuations predominantly influence the relaxation. The influence upon T 1p of the rotation of the molecules caused by their diffusion along the helix, an effect occurring only fort twisted structures, was not observed in COC in view of too long a rotational correlation time Etude experimentale de la variation de T 1 et T 1p en fonction de la frequence et de la temperature dans la phase cholesterique du carbonate de cholesteryle et oleyle, et de la variation thermique du coefficient d'autodiffusion en phase isotrope. Predominance de l'autodiffusion et des rotations moleculaires locales dans le domaine du MHz, et des fluctuations du directeur dans le domaine en kHz
TL;DR: The antagonist-sensitive binding of [3H]mepyramine to beef aortic membranes was as expected for binding to histamine H1-receptors and analysis of the binding data gave a dissociation constant of 3.0 nM for the radioligand-receptor complex.
Abstract: The antagonist-sensitive binding of [3H]mepyramine to beef aortic membranes was as expected for binding to histamine H1-receptors. [3H]mepyramine binds rapidly and in saturable fashion to the specific receptor sites, specific binding reaching equilibrium in 3 min at 37 degrees C. SCATCHARD's analysis of the binding data gave a dissociation constant of 3.0 nM for the radioligand-receptor complex and maximal number of binding sites: 31 fmol/mg protein. In the competition studies histamine H1-antagonists are more potent inhibitors of radioligand binding than H2-antagonist. They inhibit [3H]mepyramine binding in the following order: mepyramine greater than triprolidine greater than promethazine much greater than cimetidine. Binding data are in correlation with the previous pharmacological studies.
TL;DR: In this article, electric conductance and transport numbers of polyions were measured in aqueous polystyrenesulfonate solutions having different counterions, at concentrations from 2×10−3 to ∼ 10−1 basemol dm−3.
Abstract: Electric conductance and transport numbers of polyions were measured in aqueous polystyrenesulfonate solutions having different counterions, at concentrations from 2×10−3 to ∼ 10−1 basemol dm−3. From experimental data the extent of atmospheric binding of small ions to polyions was derived. The resulting fraction of free counterions was found to agree within ±5% with the coefficient of self diffusion calculated according to the theory of Jackson, Lifson, and Coriell. The molar conductance and the effective charge of the polyion were applied for the calculation of the hydrodynamic friction coefficient related to a monomer unit of the polyion.
TL;DR: In this paper, the inplane component of the dielectric constant of chiral smectic p-decyloxybenzilidene-p'-amino-2-methylbutyl cinnamate is measured as a function of temperature and magnetic field applied parallel to the C* layers.
Abstract: The in-plane component of the dielectric constant of chiral smectic p-decyloxybenzilidene-p'-amino-2-methylbutyl cinnamate is measured as a function of temperature and magnetic field applied parallel to the smectic layers. The transition from the modulated smectic C* to the uniform smectic C phase is accompanied by a drop in the dielectric constant in analogy to the incommensurate-commensurate transition in ferroelectrics. The C*-C transition line exhibits a large hysteresis and the critical field for the unwinding of the helix increases with decreasing temperature except close to the λ-line. The obtained results are in qualitative disagreement with the predictions of the Landau-de Gennes model and seem to suggest a different mechanism for the unwinding of the smectic C* helix.
Die in der Ebene liegende Komponente der Dielektrizitatskonstante von chiralem smektischem p-Dezyloxybenziliden-p'-amino-2-methylbutyl-Cinnamat wird in Abhangigkeit von Temperatur und Magnetfeld gemessen, das parallel zur smektischen Schicht angelegt wird. Der Ubergang von der modulierten smektischen C*- zur homogenen smektischen C-Phase wird von einem Knick im Verlauf der Dielektrizitatskonstante begleitet, ahnlich wie beim Ubergang inkommensurabelkommensurabel in Ferroelektrika. Die C*-C-Ubergangskurve zeigt eine grose Hysterese und das kritische Feld fur Abwicklung der Helix steigt mit abnehmender Temperatur auser in der Nahe der λ-Linie. Die erhaltenen Ergebnisse befinden sich qualitativ im Gegensatz zu den Vorhersagen des Landau-de Gennes-Modells und scheinen auf einen unterschiedlichen Mechanismus fur das Abwickeln der smektischen C*-Helix hinzuweisen.
TL;DR: In this paper, the growth of the electric dipole moment of the n-electron cluster after the adiabatic switch on of the electron-phonon interaction and the external electric field is calculated.
Abstract: Correlated hopping of many electrons in the impurity band of moderately compensated semiconductors at low temperature is studied. The growth of the electric dipole moment of the n-electron cluster after the adiabatic switch on of the electron-phonon interaction and the external electric field is calculated. One- and two-phonon processes are considered. The theory is based on the following assumptions: one-electron states in the impurity band are strongly localized, the motion of each electron is restricted to the hopping between two impurity sites, the Coulomb interaction between electrons in the cluster is strong, and the deformation potential type coupling to phonons is assumed. It is shown that the exchange of virtual phonons during the hopping events results in the renormalization of the transfer matrix elements. The calculation also reveals an interference effect between the contributions of different electrons to the current.
TL;DR: In this article, the magnetic resonance line shape in one-dimensionalally modulated structurally incommensurate systems has been evaluated for the case of a multisoliton lattice taking into account both phase and amplitude variations in space.
Abstract: The magnetic-resonance line shape in one-dimensionally modulated structurally incommensurate systems has been evaluated for the case of a multisoliton lattice taking into account both phase and amplitude variations in space. Amplitude variations significantly affect the NMR line shape outside the "plane-wave" regime. A comparison is made between the temperature dependence of the average incommensurate wave vector and the soliton density in the constant-amplitude approximation and in the case when amplitude variations are taken into account.
TL;DR: In this paper, experiments were conducted to falsify a scheme with three-dimensional time, which was later found to be a hoax. But the experiments were reported to be ineffective.
TL;DR: The tumours of different histological types showed notable differences in the relationship between proton relaxation rate (1/T1) and the corresponding water content (r).
Abstract: A series of different human brain tumours have been characterized with respect to the proton spin-lattice relaxation time (T1) and the water content. In malignant tumour tissue the mean T1 values are significantly larger than in benign ones. The tumours of different histological types showed notable differences in the relationship between proton relaxation rate (1/T1) and the corresponding water content (r). Malignant tumours exhibited a large variation in the water content in the presence of relatively small changes in relaxation rates, whilst just the opposite was true of the benign tumours and normal tissue. Taking into consideration the fast exchange between the intracellular and extracellular fluid, the (1/T1)/r relationship observed in malignant tissue is explainable by the variation in water content in the extracellular fluid due to oedema, which is most pronounced in malignant tumours. The individual response of patients to the malignant growth seems to determine the tissue water content and hence the measured relaxation time, whilst it appears that the relaxation rate and the water content of the malignant cells of the same tumour type do not vary appreciably from one patient to another. On the other hand, benign and non-tumourous tissue cells from different patients show larger variations in T1, whilst the variations in the extracellular water content are obviously smaller than in malignant tissues.
TL;DR: The hypothesis that H2-receptors are involved in the process of salivary secretion is supported, as Histamine effects on glandular elements seem to be more significant than its effect on the blood vessels.
Abstract: The aim of the present work was to establish whether the secretory process can be influenced by histamine H2-receptor antagonists, burimamide and metiamide. These drugs were applied intravenously and the secretion was evoked by the electrical stimulation of the chorda tympani nerve or by carbachol (i.v.). In addition to the measurements of the flow of saliva, the blood flow through the gland was measured in some experiments. Both H2-antagonists significantly reduced the rate of salivary secretion induced by the chorda tympani stimulation. The experiments with burimamide did not permit the calculation of dose-response relationship. From the experiments with metiamide the ED50 was 4.6 mumols/kg and Emax was 30% reduction of secretion. The secretory response to carbachol was not diminished by burimamide. In addition to the effect of metiamide on salivation, the reduction of the blood flow through the gland was observed: the effect on the blood flow was significantly smaller, and slower in onset, than the effect on salivation. These results support the hypothesis that H2-receptors are involved in the process of salivary secretion. Histamine effects on glandular elements seem to be more significant than its effect on the blood vessels.
TL;DR: In this paper, the synthesis of isomeric azolopyridopyrimidines was described, and it was shown that in many cases a transformation of a functional group with the purpose to form an annelated five-membered ring proceeded with ring opening at the pyrimidine part.
Abstract: Syntheses of isomeric azolopyridopyrimidines are described. As starting material the corresponding pyridopyrimidines were used. It could be established that in many cases a transformation of a functional group with the purpose to form an annelated five-membered ring proceeded with ring opening at the pyrimidine part. Subsequent ring closure with one carbon synthons gave then the desired tricyclic heterocycles.
TL;DR: The physiological role of histamines in salivary secretion was demonstrated and the similarity between the roles of histamine, mast cells and chromaffine-like cells in salIVary and gastric secretion is discussed.
Abstract: Histamine was found to be stored in the submandibular gland of the cat mainly in the mast cells. The amine is released from mast cells by compound 48/80 and pilocarpine. This was demonstrated in thein vivo andin vitro experiments and by histological examination. During the physiological stimulation of the gland, via the electrical stimulation of the chorda tympani nerve, significant changes of histamine content were not found. This could be explained by the increased synthesis of histamine during physiological stimulation. The physiological role of histamine in salivary secretion was demonstrated. The similarity between the roles of histamine, mast cells and chromaffine-like cells in salivary and gastric secretion is discussed.
TL;DR: In this paper, a second level trigger system using conventional wire chamber readout and NIM modules is described, where events to be processed by the on-line computer are selected in a time interval of one microsecond on the basis of number of hits in the wire chambers.
TL;DR: In this paper, the transition probability of a group of n electrons in the impurity band of a moderately compensated semiconductor was investigated, and a statistical approach was applied in the calculation of transition rates for very large clusters.
Abstract: Correlated hopping of many electrons in the impurity band of the moderately compensated semiconductor is studied. The calculation of the n-electron cluster transition rate is based on the following assumptions: the one-electron states in the impurity band are strongly localized, the motion of each electron is restricted to the hopping between two impurity sites, the electrons mutually interact by Coulomb forces, and the deformation-potential-type coupling to phonons is used. A statistical approach is applied in the calculation of transition rates for very large clusters.
Les sauts correles des plusieurs electrons dans la bande d'impuretes d'un semiconducteur legerment compense sont etudiees. Le calcul des probabilites de transition pour une groupe de n electrons est fonde sur les hypotheses suivantes: les etats electroniques dans la band d'impuretes sont fortement localises, le mouvement d'un electron est limite aux sauts entre deux sites des impuretes, les electrons interact mutuellement par des forces de Coulomb et le potentiel de deformation est utilise pour le couplage avec les phonons. La methode statistique est employee au calcul des probabilites de transition dans les cas n ≫ 1.
TL;DR: In this paper, hard and durable pellets were prepared by sintering CaSO4 and Dy2O3 with the addition of an inorganic binder, which avoided the introduction of impurities from the acid.