showing 36 of ~574560 from 574555 documents
Some Necessary Revisions of the Neuronal Model Concept of the Orienting Response
1978
Sokolov's neural trace model as well as his entropy model of the orienting response are examined. Both seem inadequate for empirical and theoretical reasons. The role of the relevance aspect of a stimulus is stressed. It is proposed to consider the information transmitted by a stimulus as in some way being weighted by the relevance of the context to which it belongs. It is furthermore proposed to restrict the neural trace concept to the physical properties of the stimulus. Major theoretical gain is achieved by viewing information content of a stimulus and its physical properties independently and by breaking the motivation determining the strength of an orienting response into a situation-s…
Species-Specific Aggregation Factor in Sponges
1978
An aggregation receptor (AR) from the siliceous sponge Suberites domuncula has been isolated and purified by chromatography to about 55% purity. The AR consists primarily of neutral carbohydrate and is characterized by a buoyant density of 1.59 g/ml and by an apparent molecular weight of 42,500. The average density of the AR on Suberite cells is about 3.8 × 10 5 per μm 2 . The AR contains considerable amounts of hexuronic acid. The isolated AR can bind not only to receptor-depleted Suberites cells but also to receptor depleted cells from another siliceous species (Geodia cydontum) . After being charged with Suberites ARs, Geodia cells form aggregates in the presence of the species-specific …
Polarographic and voltammetric methods for the determination of elements
1978
Measurements of the correlations between current, voltage and time, when microelectrodes are used, yield qualitative and quantitative information on the elemental composition of the solution investigated, if the method of measurement is properly chosen. Instrumental development today makes it possible, even at electrodes which make measurement difficult, such as the classical dropping mercury electrode, to obtain more reliable information on detection limits and number of elements detectable, by taking into account the functional interdependence of interference parameters and signal generation. Simultaneous determination of several components is possible, especially with non-linear a. c. po…
The specificity of prostaglandin E2 (PGE2) in reducing coronary vascular resistance: A comparison with adenosine.
1978
Experiments were performed on the isolated, electrically driven guinea-pig heart, perfused at constant rate. All animals were pretreated with reserpine. Myocardial contractile force (MCF), coronary perfusion pressure (CPP) and myocardial oxygen consumption (QO2) were monitored continuously. Both adenosine (ADO) and PGE2 produced a concentration-dependent decrease in the CPP. The ED50 (50% of maximum response) was 2.1 +/- 0.6 X 10(-9)M for PGE2 but 40 +/- 7 X 10(-9)M for ADO (P less than 0.01) at 1.8 mM Ca(e). This coronary vasodilation was independent of the external Ca-concentration, which was varied between 0.55-9.0 mM. PGE2 had no effect on MCF or QO2 and the effect of ADO was only sligh…
Polymerization of diacetylene carbonic acid monolayers at the gas-water interface
1978
La théorie des sous-ensembles flous au service de la décision : deux exemples d'application
1978
Deux exemples d'application de la théorie des sous-ensembles flous à l'aide à la décision sont traités dans ce texte : - une méthode de classement - la résolution complète d'un processus de prix de décision par étapes successives dans un environnement flou.
Wachstum und Wachstumsvorhersage
1978
Ausgehend von grundsatzlichen Uberlegungen uber das Schadelwachstum und die theoretischen Moglichkeiten seiner Vorhersage werden die bekannten Vorhersagemethoden erlautert und kritisch bewertet.
Control of Enzymic Hydrolysis of Polyadenylate Segment of Messenger RNA: Role of Polyadenylate-Associated Proteins
1978
The role of poly(A)-associated proteins in the breakdown of poly(A) sequences in both mammalian polyribosomes and in isolated poly(A) · protein complexes has been studied on an enzymic level. Two nucleases (alkaline exoribonuclease and endoribonuclease IV; both isolated from eukaryotic tissue), which preferentially hydrolyze poly(A) sequences, have been applied to determine the susceptibility of poly(A) in dependence on the presence of poly(A) · protein(s). Polysomes, isolated from L5178y mouse lymphoma cells, do not contain endogenous poly(A) nuclease activity. The poly(A) segment in polysomes is hydrolyzed by the exoribonuclease, irrespective of the preincubation conditions used. Pretreat…
Treatment of cryptorchidism with a potent analog of gonadotropin-releasing hormone.
1978
Pernasal therapy of cryptorchidism with D-Leu6-des-Gly10-gonadotropin-releasing hormone ethylamide (D-Leu6-des-Gly10-GnRH-EA), a potent, long-acting GnRH analog, was attempted. Eleven prepubertal cryptorchid boys received between 25 microgram once daily and 25 to 50 microgram twice daily for 5 to 12 weeks. Complete testicular descent was achieved in 4 of the 11 boys. GnRH tests (1.5 microgram/kg intravenously), conducted in six boys before treatment, after 4 weeks of treatment, and in 2 boys 3 months after treatment, did not reveal changes in gonadotropin secretion indicative of precocious puberty or of decreased hypophyseal sensitivity to GnRH. Antibodies to the GnRH analog or to GnRH coul…
Action programme éducation - Emploi. Rapport Intermédiaire
1978
Référence interne : 78023
Untersuchungen zur Aktivit�tskinetik des Isoenzymes CK-MB im Serum nach Myokardinfarkt
1978
We investigated the activity kinetics of CK-total and CK-MB in 83 patients with proven myocardial infarctions. Serial serum samples were taken at intervals of 2--6 h. The activity of isoenzym CK-MB was determined by means of the immunological inhibition method. CK-MB activity was determined in all patients. The mean peak activity of CK-MB was 65 U/l (range: 9-241 U/l). At the time of peak CK-MB activity the mean percentage CK-MB activity was 13.2% (range: 3.4--21.7%). The CK-MB activity reached its peak at 17.4 h (range: 3.0--32.5 h) after the onset of retrosternal pain. This is 1.4 h after peak CK-total activity. The mean disappearance rate constant for CK-MB (n = 31) was found to be 9.3 X…
Reductive Drug Metabolism in Isolated Perfused Rat Liver under Restricted Oxygen Supply
1978
1. Hepatic azo and nitro reductase activities were studied in the perfused rat liver under normal and restricted oxygen supply. 2. Formation of sulphanilamide or p-aminobenzoic acid from neoprontosil or p-nitrobenzoic acid under aerobic conditions of liver perfusion was negligible, even at a reduced oxygen saturation of a pO2 of 300 mm Hg in the haemoglobinfree perfusion system. At a pO2 of 200 mm Hg reductase activities were almost maximal. 3. Conjugation of sulphanilamide (0-08 mM) was similar under aerobic and anaerobic conditions. Hepatic elimination of p-aminobenzoic acid (0-08 mM) showed an oxygen-dependent increase for 15 min after addition of substrate. 4. p-Nitroanisole demethylati…
Species-Specific Aggregation Factor in Sponges
1978
An aggregation factor (AF) from the siliceous sponge Suberites domuncula has been isolated and purified by the following steps: Sepharose 2 B gel chromatography, sucrose gradient, Nonidet treatment, Sephadex G-100 gel chromatography and DEAE-Sephadex ion-exchange chromatography. By this procedure the AF was purified 1340-fold with a 63% yield nearly to homogeneity. The AF is originally associated with large particles, characterized by a sedimentation of 2200 S. These particles have been visualized electron microscopically; they are characterized by a filament-like shape of a length of 3400 A and a cross-sectional diameter of 230 A. The purified, low-molecular weight AF has a buoyant density…
Enhancement of Nitro Reduction in Rat Liver Microsomes by Haemin and Haemoproteins
1978
1. Reductive metabolism of p-nitrobenzoic acid and neoprontosil in rat liver microsomes was studied in the presence of haemin, haemoglobin and myoglobin. 2. Microsomal nitro reduction is enhanced 4-fold in the presence of haemoglobin, whereas azo reduction is not affected. 3. Microsomal nitro reduction is enhanced to a similar extent by haemoglobin, haemin and boiled haemoglobin, whereas myoglobin is about half as active. 4. Maximal enhancement of microsomal nitro reductase activity by haemoglobin is achieved at high substrate concentration (6 mM) and low microsomal protein concentration (0.5--1.0 mg/ml). 5. Control microsomal nitro reduction as well as the haemoglobin-enhanced microsomal n…
Some generalizations of the center of a ring
1978
Si generalizza la nozione di ipercentro introdotta da Herstein in [3] e si trova una forma equivalente alla congettura di Koethe.
The electrochemistry of carbon monoxide reductive cyclotetramerization to squarate anion
1978
Abstract The electrochemical reduction, of carbon monoxide to C4O2−4 squarate anion is investigated. Particular attention is devoted to the influence that solvents, electrolytes, electrodes and carbon monoxide pressure have on the yields. The main feature appears to be that strictly controlled conditions are not necessary for cyclotetramerization. In dmf — Bu4NBr the following yields vs reacted CO and circulated charge were obtained with different cathodes: Pt(49%, 34%); Au(48%, 29%); Al(47%, 38%); stainless steel (36%, 33%); graphite (39%, 31%). A distinct influence of the supporting electrolyte (inorganic and tetraalkylammonium halides) was however observed.
Les conditions nécessaires au développement de la recherche. Analyse de formations de recherche de petite et moyenne dimension à l'université de Dijon
1978
référence interne : 75020
High-performance liquid chromatographic separation of esters of 4-hydroxymethyl-7-methoxy-coumarin
1978
Molekulare Deutung der Umwandlungswärmen bei den Modifikationsübergängen des n-Tritriacontans
1978
Ausgehend von dem durch die Experimente nahegelegten Bild wurden Modellrechnungen angestellt, um die fur die drei Modifikationsumwandlungen desn-Tritriacontans gemessenen Umwandlungsenthalpien und -entropien molekular zu deuten.
Gleichgewichtskonzentrationen der cyclischen Oligomeren bei der Polymerisation von 1,3,6,9-Tetraoxacycloundecan
1978
Transcatheter embolization of the kidney with butyl-2-cyanoacrylate: Experimental and clinical results
1978
The technique and efficacy of therapeutic catheter embolization of the kidney with butyl-2-cyanoacrylate (Histoacryl) were studied in 80 rabbits (including control groups) and in 10 dogs. A mixture of butyl-2-cyanoacrylate, 50% glucose, and tantalum powder was used for the embolization. Complete and permanent vascular occlusion was found in nearly all cases. The main complication observed was a reflux of embolizing material into the lumbar arteries, which occurred in seven rabbits. Clinically, therapeutic embolization was performed in six patients with hypernephroma. The indication for embolization in these patients, as well as in two others with iatrogenic lesions, was pronounced hematuria…
Segmental contribution to forces in vertical jump.
1978
Performance of a vertical jump was analyzed with respect to the contribution of the different body segments to the forces acting on the whole body center of gravity. Both cinematograph and force-platform techniques were employed. The data disclosed that the take-off velocity in vertical jumps was caused by the different components as follows: knee extension 56%, plantar flexion 22%, trunk extension 10%, arm swing 10%, and head swing 2%. However, the average take-off velocity of the total performance (3.03 m/s) was only 76% from the theoretical maximum calculated from the segmental analyses. Optimal timing of the segmental performances was calculated to increase this “efficiency” to 84%. Gre…
Determinant and inverse of a sum of matrices with applications in economics and statistics
1978
In this note we present some useful tools concerning the determinant and the inverse of the sum of two matrices. Some of the results shown here are found in the statistical and econometric literature, but often without proof and without a clear statement of the conditions under which they hold. Some other results, however, are believed to be original. A number of applications in the fields of economics and statistics are given.
On the imprecision of consumer's spatial preferences
1978
Faced with a set of needs of different intensities and which he perceives more or less indistinctly, a consumer is not normally capable of selecting among the elements belonging to his set of possible consumptions, those he prefers or is indifferent to and those from which he is likely to derive utility. Moreover the goods and services are attainable to different degrees (available in supply space) and his knowledge is perfect only in border-line cases with the result that his world is generally imprecise. Even someone with an exceptional gift for discrimination is not capable of formulating for any pair of goods, his preference or indifference according to binary logic. The purpose of this…
PRIMARY BILIARY CIRRHOSIS AND CŒLIAC DISEASE
1978
The binding of intravenous and oral biliary contrast agents to human and bovine serum albumin
1978
The binding of two homologous series of oral and intravenous biliary contrast agents to human and bovine serum albumin was investigated using the gel filtration technique. All intravenous compounds are bound to human serum albumin via one high affinity and several low affinity binding sites. Within the concentration range investigated, about 3--5 high affinity binding sites for the oral compounds were found on human serum albumin. In general, the intravenous compounds have a greater affinity for human serum albumin than the oral compounds. No significant differences were found for the binding of the oral compounds to human or bovine serum albumin, while the intravenous compounds have a high…
Anwendung der Mößbauer-Spektroskopie auf die Untersuchung von Deckschichten in Naturumlaufkesseln
1978
57Fe-Mosbauer-spektroskopische Transmissions- und Reflexionsmessungen wurden zur Aufklarung der qualitativen und quantitativen Zusammensetzung von Deckschichten auf der Innenseite von Rohren aus Naturumlaufkesseln vorgenommen. Die Deckschichten waren bei 120 bis 174 atu, 320 bis 353 °C, einem pH-Wert zwischen 9,5 und 10,5 und einem Gehalt an P2O5 und SiO2 von < 10 bzw. < 4 mg/l auf den Rohrinnenflachen (Werkstoff 15 Mo 3: 0,12%C, 0,15% Si, 0,5% Mn, 0,04% P, 0,04% S, ⩽ 0,3% Cr, 0,25% Mo, Rest Fe; St. 45. 8. III: < 0,22% C, 0,1% Si, ⩾ 0,45% Mn, 0,05% P, 0,05% S, ⩽ 0,3% Cr, Rest Fe) innerhalb von maximal 127000 h entstanden. Die Mosbauer-spektroskopischen Untersuchungen, unterstutzt durch eine…
Gonadotropinsekretion nach Stimulation mit einem hochwirksamen Analogon des Gonadotropin-Releasing-Hormon (GnRH) bei gesunden M�nnern
1978
Potente langwirksame GnRH-Analoga sind von besonderem Interesse fur die Therapie des hypogonadotropen Hypogonadismus hypothalamischer Genese und des Kryptorchismus.
Situation en Mars 1976 des élèves sortis en juin 1975 des classes terminales de DUT, BTS, BEP, CAP
1978
référence interne : 78010
Simultaneous Balloon Occlusion of the Renal Artery and Hypothermic Perfusion in in Situ Surgery of the Kidney
1978
AbstractRenal ischemia and cooling may be achieved by intraluminal balloon occlusion and intermittent hypothermic perfusion using a double lumen, balloon-tipped catheter introduced into the renal artery percutaneously. This technique was used successfully in 26 of 31 extensive nephrolithotomies, eliminating the need for dissection and clamping of the renal artery and intricate surface cooling. Intrarenal operations could be performed as effectively as with clamp occlusion. Despite a mean ischemia time of 54 minutes the individual 131I-hippuran clearance of the operated kidneys was only reduced to a mean 78.4 per cent of the preoperative value 2 to 3 weeks postoperatively and increased to 92…
Investigation of the superstructure of native collagen by a combination of small angle X-ray scattering, electron microscopy and light diffraction
1978
It is shown that there exists a direct correlation between the light diffraction pattern of an electron-microscopical picture and the X-ray small angle scattering. By this means it can be proved for native collagen prepared by a special method that the density pattern of stained samples imaged in the electron microscopy is identical with the density pattern available from moist fibres. The reflex intensities of the small angle X-ray scattering are taken for calculating the density structure whereby the necessary phases are delivered by the electron microscopic examination combined with light diffraction.
Regional distribution of high-affinity L-tryptophan uptake in rat brain
1978
Abstract L-tryptophan is accumulated by slices of seven regions of the rat brain in a saturable, energy-depending fashion, with K m -values ranging from 53 to 142 μM. The maximal number of L-tryptophan accumulating sites differs only by about two-fold for the brain regions investigated. The regional distribution of the high-affinity L-tryptophan uptake does not correlate with the amount of serotonin synaptosomal uptake and apparent receptor binding. It is assumed that a specific role of the L-tryptophan uptake system within the serotoninergic system in the brain is questionable.
The toxicity of MCPA to fish. Light and electron microscopy and the chemical analysis of the tissue.
1978
PHOSPHORORGANISCHE VERBINDUNGEN 851SYNTHESE UND ANWENDUNG OPTISCH AKTIVER TERTIÄRER PHOSPHINE ALS CO-KATALYSATOREN DER HOMOGENHYDRIERUNG MIT RHODIUM-…
1978
Abstract Die Darstellung der optisch aktiven Methyl-n-propyl(bzw.-isopropyl)arylphosphine 1 bis 8 wird beschrieben. Hierbei ist Aryl: p-Methoxyphenyl (1 und 2), p-Dimethylaminophenyl (3 und 4), o-Methoxyphenyl (5 und 6), o-Dimethyl-aminophenyl (7) und o-Aminophenyl (8). Die Phosphine 1 bis 8 werden als optisch aktive Co-Katalysatoren bei der Homogenhydrierung von α- und s-Methylzimtsaureethylester, der α-Acetaminoacrylsaure und der α-Acetaminozimtsaure mit Rhodium-Phosphinkomplexen eingesetzt und jeweils die optische Induktion bestimmt. Folgende Ergebnisse (Vgl. die Tabellen 1 bis 4) wurden erhalten: 1) Die CH3O-Gruppe und N(CH3)2-Gruppe verandern unabhangig von ihrer Stellung die optische …
Aerobic performance capacity in athletes
1978
Maximal oxygen uptake (max\(\dot V\)O2) in leg and arm work, succinate dehydrogenase activity (SDH) and percentage of slow twitch fibers (%ST fibers) in M. vastus lateralis (VL), M. gastrocnemius c.l. (GL) and M. deltoideus (D) were studied in 89 athletes practising 11 different sport events. It was found that maximal oxygen uptake correlated positively with %ST fibers and SDH activity in M. VL. The SDH activity and %ST fibers in M. VL correlated also with one another. The results suggest that oxidative capacity of the muscles is not the limiting factor for maximal oxygen uptake. The role of the oxidative capacity of the muscles might be important during submaximal work of long duration and…
Blood volume and extracellular space (ECS) of the whole body and some organs of the rat.
1978
Methods are described for estimation of blood volume and extracellular space (ECS) in the whole body and in some organs with 51Cr, 14C-thiocyanate and 3H-inulin. A mean blood volume of 47 ml/kg, a thiocyanate space of 350 ml/kg and a inulin space of 288 ml/kg were determined in the rat. The corresponding values of organs are shown in figures 1--3.