Showing papers by "Ghent University published in 1970"
TL;DR: Two proteins present in noradrenergic vesicles of the splenic nerve (dopamine beta-hydroxylase and chromogranin A) are released into the perfusate from the spleen when thesplenic nerve is stimulated.
Abstract: Two proteins present in noradrenergic vesicles of the splenic nerve (dopamine beta-hydroxylase and chromogranin A) are released into the perfusate from the spleen when the splenic nerve is stimulated. Experiments in which drugs were added to the perfusion fluid showed that the proteins were released from terminals of the splenic nerve. There was a correlation between the amounts of the proteins released and the quantity of noradrenaline released; and the release process was dependent upon calcium. It is suggested that the proteins are released from the large dense-cored vesicles present in the terminals of the splenic nerve, and that secretion from these vesicles occurs by exocytosis.
173 citations
156 citations
TL;DR: The subcellular particles in axons of the splenic nerve have been studied by centifrugation techniques and only one type of noradrenergic vesicle could be demonstrated in density gradient centrifugation.
Abstract: The subcellular particles in axons of the splenic nerve have been studied by centifrugation techniques. By differential centifrugation, five different types of particle could be distinguished and partly separated: noradrenaline-containing particles (noradrenergic vesicles), large and small lysosomes, mitochondria, and microsomal particles. In density gradient centrifugation, only one type of noradrenergic vesicle could he demonstrated. The noradrenergic vesicles and the mitochondria contain ATP. Two proteins (chromogranin A and dopamine β-hydroxylase) are present in the noradrenergic vesicles.
130 citations
TL;DR: In this article, the authors look at how mainstream media are currently reacting to the trend of citizen media and identify similarities and differences that hint at the professional, organizational, socio-cultural and economic factors influencing the evolution of participatory journalism.
Abstract: This paper looks at how mainstream media are currently reacting to the trend of citizen media. In order to look beyond the hype and high expectations about user generated content, we first try to put the debate on citizen and participatory journalism in context. We argue that the revived interest in participatory journalism is the result of both external developments in society and internal evolutions in journalism. Next, we analyze these developments in four European countries – Belgium, Finland, Germany and Spain – in order to identify similarities and differences that hint at the (professional, organizational, socio-cultural and economic) factors influencing the evolution of participatory journalism. Data collected suggests that despite of the differences in context, media in any of the four countries tend to develop very limited opportunities for audience participation. The professional culture of journalists is suggested as the main factor preventing the development of participatory projects, while marketing and business strategies somehow push for the exploration of such proposals.
125 citations
TL;DR: The fat body of allatectomized long-day females, has the same structure as that of short day beetles, and a lack of juvenile hormone induces the proteinaceous bodies, which conditions are in contrast to the observed effects of castration.
Abstract: In the fat body of ovipositing female Colorado beetles, two types of lobes occur. The first type, the internal fat body, is highly specialised for protein synthesis. A lobe of the second type, the peripheral fat body, contains two types of cells, oenocytes and glycogen cells. Ovariectomy, performed at adult moult results in hypertrophy of the glycogen cells of the peripheral fat body. The lobes are characterized by the storage of lipid bodies and glycogen and by numerous mitochondria. Short-day conditions ab ovo, which induce diapause in adults, also result in hypertrophy of glycogen cells of the peripheral fat body. Furthermore, only few mitochondria occur but many proteinaceous bodies may be observed, which conditions are in contrast to the observed effects of castration. The fat body of allatectomized long-day females, has the same structure as that of short day beetles. Consequently a lack of juvenile hormone induces the proteinaceous bodies.
63 citations
TL;DR: In this article, the authors present biochemical evidence for the existence of two types of noradrenaline storage particles in the dog spleen and compare some of their properties with those of the bovine splenic nerve.
Abstract: THE existence of different noradrenaline pools in sympathetically innervated tissues has been proposed on the basis of both pharmacological and biochemical studies1,2. Recent morphological evidence3,4, showing that the terminals of splenic nerves contain two distinct size populations of granulated vesicles and that only one of them is present in the preterminal processes, has given additional support to this theory. We now present biochemical evidence for the existence of two types of noradrenaline storage particles in the dog spleen and compare some of their properties with those of the noradrenaline vesicles of bovine splenic nerve.
59 citations
01 Jan 1970
56 citations
01 Mar 1970
TL;DR: In this article, explicit expressions of the Lyapunov functions and the transient-stability regions are computed for multimachine power systems and the dependence of the stability regions on the damping torques is investigated.
Abstract: The paper is a contribution to the application of Lyapunov's theory to the analysis of transient power-system stability. The technique of the paper originates with a theorem introduced by Anderson to prove the generalised Popov criterion for multivaiable fedback systems. Explicit expressions of the Lyapunov functions and the transient-stability regions are computed for multimachine power systems. It is shown that the obtained Lyapunov functions yield better estimates of the stability regions than the energy function which was used in some recent papers. The dependence of the stability regions on the damping torques is investigated. It is shown that optimum-stability results are obtained if particular relationships between damping torques and inertial constants are satisfied.
39 citations
TL;DR: In this paper, a method for determining the displacement component in a chosen direction on the surface of a deformed object is described, based on hologram interferometry and uses two illumination waves.
39 citations
TL;DR: In this paper, the Tamm-Dancoff approximation has been applied to a calculation of the low-lying states in single-closed-shell nuclei with N = 82 neutrons.
37 citations
01 May 1970
TL;DR: In this paper, the collapse pressure with monolayers of cholesterol with either ethyl palmitate or triglycerides above and below the melting points of the alkyl compounds was measured.
Abstract: Mixed monolayers are of technological importance and also of interest because of their relevance to many natural systems. Determination of the miscibility of the components is necessary before an understanding of the molecular interactions can be reached. The variation of collapse pressure with monolayer composition can be used to obtain information on the degree of miscibility. Since kinetic effects can alter the collapse, the collapse pressures were measured for monolayers of cholesterol with either ethyl palmitate or triglycerides above and below the melting points of the alkyl compounds. Consideration of partial molecular areas and of the two dimensional phase rule indicates that immiscible collapsed phases can occur. The criterion of enhanced surface pressure stability in mixed monolayers only applies when the components are miscible both in the monolayer and collapsed phase. When the latter situation occurs a theoretical analysis of the variation of collapse pressure with monolayer composition is possible. Reasonable agreement between theory and experiment is found.
TL;DR: Isometric contractions of isolated soleus muscles of 3 weeks old rats show a potentiation of the maximal twitch tension when the PCO2 is increased, or when the [HCO3−] is increased with a reciprocal decrease in [Cl−].
Abstract: Isometric contractions of isolated soleus muscles of 3 weeks old rats show a potentiation of the maximal twitch tension when theP
CO2 is increased, or when the [HCO
3
−
] is increased with a reciprocal decrease in [Cl−]. The reverse response is observed on decrease of theP
CO2 and on decrease of the [HCO
3
−
] with a reciprocal increase in [Cl−]. The addition of lactate ions results in a potentiation of the maximal twitch, whether accompanied by a reciprocal decrease in [HCO
3
−
] or in [Cl−]. The maximal tetanic tension is augmented by rising theP
CO2, by increasing the [HCO
3
−
] with simultaneous lowering of [Cl−], or by the addition of lactate ions.
TL;DR: In this article, pure hops-derived substances were added to unhopped beer to produce a sun-struck flavour with cis-isohumulone, trans-isopharmal-mercaptan, cis-1-isoha-mulone and trans-2-mihal.
Abstract: Pure hops-derived substances were added to unhopped beer. Illumination only produced a sun-struck flavour with cis-isohumulone, trans-isohumulone and racemic trans-isohumulone. It seems that 3-methyl-butenyl-mercaptan is not or not alone responsible for sun-struck flavour.
Tests trials show that trans-isohumulone, cis-isohumulone, racemic trans-isohumulone, trans-1-isohumulone and cis-1-isohumulone do not show significant differences in bitter taste and bittering power. Fresh solutions of these bitter acids are not as bitter as solutions which have been kept for a few weeks.
TL;DR: It is concluded that the ER is not involved in the synthesis of large quantities of yolk proteins, and the Golgi elements of the follicle cells produce electron-dense secretion vesicles which are thought to contribute in the formation of crystals enclosed in the proteid yolk bodies and also in chorion formation.
TL;DR: The lactate response to an intense hypocapnia was decreased in animals maintained 24 hours in hypoxic alkalosis and increased after 24 hours hypercapnia and the results are discussed in relation to the hypothesis that the lactate concentration response in brain in these conditions is related to local pH.
Abstract: The influence of acute changes inPaCO2on lactate concentration in brain and blood was studied in hypercapnic and hypocapnic rats. Lactate in brain increases markedly whenPCO2is acutely decreased by severe hyperventilation. Compared with the observations in normal rats, the lactate response to an intense hypocapnia was decreased in animals maintained 24 hours in hypoxic alkalosis and increased after 24 hours hypercapnia. The results are discussed in relation to the hypothesis that the lactate concentration response in brain in these conditions is related to local pH. Incubation studies of brain tissue, in whichPCO2or (and) [HCO3−] were varied, show that lactate and pyruvate concentration and glucose consumption increase while the lactate/pyruvate ratio decreases when the pH of the incubation fluid is augmented. In an iso-pH system, lactate and pyruvate concentration, glucose consumption and L/P ratio increase with increasing [HCO3−]. The possible mechanisms and the possible importance of these metabolic variations are discussed.
TL;DR: In this article, a rigorous algebraic method for calculating all the CO stretching force constants of the complexes of general formula LM(CO)5 is proposed, yielding at once all the solutions, whether physically acceptable or not.
31 Oct 1970
TL;DR: In this article, a relative method for the determination of oxygen in steel via the 16O(n,p)16N reaction by means of 14-MeV neutrons is described.
Abstract: A relative method for the determination of oxygen in steel via the 16O(n,p)16N reaction by means of 14-MeV neutrons is described. A standard is irradiated immediately behind the sample and the induced activities are counted simultaneously with two separate but identical detector systems. The standard mixture (ca. 5 g of graphite plus iron oxide containing 80 mg of oxygen per g) is compressed into a steel capsule of the same external dimensions as the samples (26 mm diameter, 9 mm thick). Dimensional tolerances, choice and purity control of the oxygen compound and preparation of the standard mixture are discussed. Fast neutron shielding, absorption of fast neutrons, self-absorption of the 16N /gg-rays and the average neutron flux in sample and standards are considered and a total correction factor is established. Flux inhomogeneities and differences in counting geometry and discriminator setting can be determined by irradiation and counting of two identical standards. The accuracy of this method was checked by comparison of the results with those of the reducing fusion method; satisfactory agreement was observed, although the activation results tended to be slightly higher. The mean long-term standard deviation for analysis of a given sample over a period of 6 months was found to be ±3%.
TL;DR: The kinetics of the cationic polymerization of 3,3-dimethylthietane with triethyloxonium tetrafluoroborate in methylene chloride at 20°C have been studied in this paper.
Abstract: The kinetics of the cationic polymerization of 3,3-dimethylthietane with triethyloxonium tetrafluoroborate in methylene chloride at 20°C have been studied. The polymerization is characterized by a very fast initiation reaction. The propagation occurs most probably via cyclic sulphonium ions. The existence of a termination by reaction of the growing chains with sulphur atoms of the polymer chain was demonstrated by kinetic and molecular weight measurements. The propagation constants kp and termination constants kt at different temperatures were calculated.
The enthalpies of activation for the propagation and termination reactions are, respectively, ΔH≠p = 12.5 kcal mole−1, ΔH≠t = 7.4 kcal mole−1, and the corresponding entropies of activation are ΔS≠p = -26 cal deg−1 mole−1, ΔS≠t = -49 cal deg−1 mole−1.
Die Kinetik der Polymerisation von 3.3-Dimethylthietan mit Triathyloxoniumtetrafluoroborat als Katalysator in Methylenchlorid als Losungsmittel wurde untersucht. Die Polymerisation hat eine sehr schnelle Initiierung, und die Wachstumsreaktion verlauft wahrscheinlich uber cyclische Sulphoniumionen. Der Abbruch der Polymerisation durch Reaktion wachsender Ketten mit Schwefelatomen aus der Polymerkette konnte durch kinetische Messungen und Molekulargewichtsbestimmungen bewiesen werden. Die Wachstumskonstanten und Abbruchskonstanten wurden bei verschiedenen Temperaturen gemessen, und aus diesen Werten wurde die Aktivierungsenthalpie und die Entropie fur die Wachstumsreaktion (ΔH≠p = 12,5 kcal Mol−1; ΔS≠p = -26 cal Grad−1 Mol−1) und fur die Abbruchsreaktion (ΔH≠t = 7,4 kcal Mol−1; ΔS≠p = -49 cal Grad−1 Mol−1) berechnet.
TL;DR: The vascular effects of nitroglycerin did not seem to be determined by its metabolism or plasma levels, and blood pressure was normal despite high plasma levels.
TL;DR: In this article, the anodic behavior of the V 2 O 5 single crystal electrode is investigated in the dark and under illumination, in indifferent electrolyte and in the presence of various reducing agents.
01 Jun 1970
TL;DR: In this paper, general formulas and equivalent circuits are given for a resonant cavity coupled to the end plane of a wave guide, inserted between two waveguides, and coupled to a sidewall of the waveguide.
Abstract: General formulas and equivalent circuits are given for a resonant cavity coupled to the end plane of a wave guide, inserted between two waveguides, and coupled to the sidewall of a waveguide. The aperture, the cavity and the waveguides are of arbitrary shape.
TL;DR: An cours de l'annee 1967, nous avons fait l'etude qualitative and quantitative des gasteropodes presents dans un terrain marecageux aux environs de Gand (Belgique) as discussed by the authors.
Abstract: An cours de l'annee 1967, nous avons fait l'etude qualitative et quantitative des gasteropodes presents dans un terrain marecageux aux environs de Gand (Belgique) Deux fois par mois des echantillons de sediment ont ete preleves ainsi qu'un volume determine de vegetation infralittorale (Elodea canadensis Rich etCeratophyllum demersum L) Les facteurs abiotiques du milieu (temperature, pH, chloronite, oxygene dissous matieres organiques) furent suivis tout le long de l'annee
TL;DR: Using the Cotton and Kraihanzel force field, a more exact direct method was applied for calculating the CO stretching force constants of substituted metal carbonyls of general formula cis -L 2 M(CO) 4 (M = Mo, W, Cr; L = phosphine or amine) and of complexes of formula [R 2 MFe(CO), 4 ] 2 (M, Si, Ge, Sn or Pb),(R 3 Sn) 2 Fe(CO).
TL;DR: In this paper, the second order reaction interferences in activation analysis have been derived and a simple approximation as well as the exact solution have been investigated for fast and accurate calculations, without the need of a computer with high precision arithmetic.
Abstract: Equations to calculate the second order reaction interferences in activation analysis have been derived. A simple approximation as well as the exact solution have been investigated. A new algorithm is proposed for fast and accurate calculations, without the need of a computer with high precision arithmetic. The method can be used for all higher order reaction chains.
TL;DR: In this paper, the spatial and temporal variation of net radiation in canopies of oats, beans, sunflower and corn is discussed, and the analysis showed highly asymmetrical distributions suggesting that the characterization of the net radiation within a canopy by a mean value may be grossly inadequate.
TL;DR: It is believed that this constitutes the first record of fertile experimental secondary cysts of E. granulosus containing brood capsules with fully developed protoscolices.
Abstract: The development of secondary E. granulosus cysts has been studied in three different strains of mice following subcutaneous injections of protoscolices. Differing results in preliminary experiments were due to different storage times at a low temperature. In the main comparative experiment (No. 4) the take was very high (95%) and no strain difference could be observed. After 15 months the largest parasitic formation weighed 6 g, the volume of the largest single cyst was 3.5 ml and the largest parasite-host ratio (w:w) amounted to 13%. On two occasions a secondary cyst has been found containing brood capsules with fully developed protoscolices. Both cysts were from NMRI mice, 12 and 15 months p. i. and had diameters of 1.5 and 2 cm, respectively. It is believed that this constitutes the first record of fertile experimental secondary cysts of E. granulosus.
TL;DR: In this article, level schemes of 117, 119, 121 Sb are calculated in a unified model approach with surface vibrations coupled to the proton single-particle motion, and octupole vibrations are necessary to explain low-lying negative parity states.
TL;DR: The vasodilator effects of nitroglycerin on perfused vessels or vascular strips were dependent on the time of its administration; administration during an existing contraction was much more effective than administration before contraction.
TL;DR: In this article, Vibrational assignments are proposed based on characteristic group frequencies, rotational splitting in the IR (in gas phase) and Raman polarisation data of the methylbromogermanes.