showing 36 of ~574560 from 574555 documents
Dielectric properties of (KBr)1-x (KCN)x
1982
The temperature dependence of the dielectric constant of (KBr)1−x (KCN) x was measured at frequencies of 87.5 Hz, 1, 10 and 100 kHz for concentrations ofx=0, 0.01, 0.04, 0.14, 0.25, and 0.50. Both the real and the imaginary part showed maxima at characteristic temperatures which depend on the measuring frequency and the concentration. The results are analogous to the behaviour of the magnetic susceptibility in spin glasses and support the existence of an orientational glass state.
Heat-Shock Proteins in Sea Urchin Embryos
1982
The production of heat-shock proteins in sea urchin embryos is accompanied by the appearance at the polysomal level of their relative mRNAs, as shown by their translation in a cell-free system; thus suggesting that the regulation of their production occurs at a transcriptional level. The mechanism for the inhibition of the bulk protein synthesis and for its reversal on the other hand should be looked for at a posttranscriptional level, since both these phenomena occur also in the presence of actinomycin D. The heat-shock proteins produced as early as at the mesenchyme blastula stage persist within the embryo at least till the pluteus stage.
On the path representation of networks
1982
A compact data structure for networks is obtained by storing arcs of paths sequentially. This structure allows forward and backward access from a node to its neighbors.
Fits of the baryon magnetic moments to the quark model and spectrum-generating SU(3)
1982
We show that for theoretical as well as phenomenological reasons the baryon magnetic moments that fulfill simple group transformation properties should be taken in intrinsic rather than nuclear magnetons. A fit of the recent experimental data to the reduced matrix elements of the usual octet electromagnetic current is still not good, and in order to obtain acceptable agreement, one has to add correction terms to the octet current. We have texted two kinds of corrections: U-spin-scalar terms, which are singles out by the model-independent algebraic properties of the hadron electromagnetic current, and octet U-spin vectors, which could come from quark-mass breaking in a nonrelativistic quark …
Insertion of isocyanides into the palladium-(2-pyridyl) bond
1982
The reaction of the pyridyl-bridged binuclear complex [PdBr(μ-2-C5H4N)(PPh3)]2 with isocyynides CNR (R p-C6H4OMe, Me, C6H11) yields the complex PdBr{(&2.dbnd;NR)C(&2.dbnd;NR) (2-C5H4N)}(PPh3)] containing a C,N-chelated 1,2-bis(imino)-2-(2-pyridyl)ethyl group, which results from successive insertions of two isocyanides molecules into the palladium2-pyridyl bond. The mononuclear compound trans-[PdBr(2-C5H4N)(PMePh2)2] readily reacts with various CNR ligands (R p-C6H4OMe, Me, C6H11, CMe3) to give the imino(2-pyridyl)methylpalladium(II) derivatives, trans-[Pdbr{C(=NR)(2-C5H4N)} (PMePh2)2].
General occurrence of polar twisted minima in the ionic singlet excited surfaces of polyenes
1982
Except for a few cases, the lowest closed shell SCF solutions for the twisted geometries of polyenes involves delocalized nonpolarized MO’s, and represents a meaningless mixture of radicalar gound state and ionic excited states. Higher (quasi) solutions allow a realistic approach of the polarized ionic states. Orthogonality to the radicalar ground state may be imposed without important loss of energy. Further extensive CI does not modify significantly the situation. These statements are illustrated through ab initio calculations of butadiene and hexatriene. This approach allows us to show that slight distortions stablize polar minima even in ’’homosymmetric’’ molecules such as all‐trans hex…
Decomposition of organic matter with molten alkali: determination of arsenic and antimony in organic compounds
1982
Decomposition of organic matter with molten alkali has been examined as a method of opening out organic matrices for elemental detection and/or determination. The fusion product is readily soluble. Arsenic and antimony in organic compounds can be determined iodimetrically after mineralization by this fusion method.
Studies on erythrocyte acetylcholinesterase in essential hypertension.
1982
There is accumulating evidence that acetylcholinesterase (AChE might be involved in the transport of sodium across biological membranes. Consequently, because in primary hypertension abnormalities in the transport of sodium by red blood cells have been documented. AChE activities were measured in hemoglobin-free red-blood-cell membranes of patients with essential hypertension. In the absence of any effectors, the Michaelis constant of AChE for acetylcholine (Km) was 1.57 . 10(-5) mol/l, both in normotensives and in hypertensives. Sodium inhibited AChE at low substrate concentrations, whereas the enzyme was activated by sodium at moderate and high substrate levels. With increasing sodium, th…
Histamine binding to H2 receptors stimulates phospholipid methylation in mast cells
1982
Rat peritoneal mast cells incubated in vitro in the presence of L-[methyl-3H] methionine and exposed to histamine undergo a rapid but transient increase in phospholipid methylation. By using specific H1- and H2-receptor antagonists, and histamine analogues differing in their H2-receptor agonist potency, it has been demonstrated that this metabolic event is dependent on histamine binding to H2-receptors.
Isoprenaline and forskolin increase evoked vasopressin release from rat pituitary
1982
Isolated neurointermediate lobes of rat pituitaries were incubated in Krebs solution. The vasopressin release evoked by electrical stimulation (0.2 ms, 80 V, 15 Hz, 10 s trains at 10 s intervals for a total of 10 min) was completely inhibited by tetrodotoxin. Isoprenaline increased the evoked vasopressin release to a maximum of 60% (EC50 10 nM) and this effect was antagonized surmountably by propranolol. Forskolin increased the vasopressin release by 98%. These results suggest the presence within the neurohypophysis of a beta-adrenoceptor-linked adenylate cyclase facilitating vasopressin secretion.
false
1982
false
1982
Thermometric study of the dissociation equilibria of the maleinimidodioxime
1982
The values of the dissociation constants of the maleinimidodioxime are potentiometrically determined at various ionic strengths, and extrapolated to zero ionic strength (pK1T=10.41;pk2T=11.60). From these values and from the thermometric titration curves the enthalpies of neutralization (ΔHN1=−21.76,ΔHN2=−23.77 kJ/mol) and the thermodynamic parameters of dissociation of this substance at 25.0 °C are determined (ΔG1θ=59.41,ΔG2θ=66.23,ΔH1θ=34.06,ΔH2θ=32.05 kJ/mol;ΔS1θ=−85.06,ΔS2θ=−114.64 J/(K mol)).
Metabolism of Saccharomyces cerevisiae envelope mannoproteins.
1982
By pulse and chase labeling experiments, two independent mannoprotein pools have been found associated with the Saccharomyces cerevisiae envelope. One of them probably corresponds to mannoproteins localized in the periplasmic space. These molecules showed a high turnover rate at 28 degrees C. The second pool is formed by intrinsic wall mannoproteins which are apparently stable for long periods of time, after a small initial turnover. These results suggest that at least part of the mannoproteins initially found in the periplasmic space may move into the wall. The time lag between the addition of the radioactive precursors and their incorporation in the cell envelope (20-30 min for amino acid…
Tumorhemmende wirkstoffe, XIII [1] aromatisch carbocyclisch und heterocyclisch substituierte 2-perfluoralkylpyrimido[1,2-a]benzimidazole
1982
Zusammenfassung Aus der Umsetzung von 2-Aminobenzimidazol mit den entsprechende Fluoralkylgruppen tragenden β-Diketonen sind die folgenden 2-Perfluoralkylpyrimido[1,2-a]benzimidazole hervorgegangen: 4-Phenyl-, 4-(2'-Naphthyl)-, 4-(3'-Pyridyl)-, 4-(2'-Furyl)- und 4-(2'-Thienyl)-2-trifluormethylpyrimido[1,2-a] benzimidazol, ferner 4-(2'-Thienyl)-2-heptafluorpropylpyrimido[1,2-a]benzimidazol.
The Effects of Chlorotrianisene (Tace) on Kinetics of 3H-testosterone Metabolism in Patients with Carcinoma of the Prostate
1982
Summary— Alterations in the metabolism of testosterone and plasma levels of testosterone, luteinising hormone (LH), follicle stimulating hormone (FSH), prolactin and oestradiol were studied in 6 patients with newly diagnosed prostatic carcinoma before and during treatment with chlorotrianisene at a daily dosage of 48 mg for 14 days. Parameters of plasma kinetics were determined according to the single injection technique and the 2-compartment model, and the plasma hormones by radioimmunoassay. Chlorotrianisene altered neither plasma levels of testosterone, gonadotrophins, prolactin and oestradiol, nor metabolic clearance rate, production rate and other kinetic parameters of testosterone. Th…
Thermodynamic and neutron diffraction studies of the nucleation of solid4He on graphite
1982
The nucleation of solid layers of4He on the surface of exfoliated graphite (Grafoil) was investigated by thermodynamic and neutron diffraction measurements. The thermodynamic measurements consisted of recording isopycnals in the vicinity of the melting curve. The isopycnals show a rounding in comparison to the bulk ones, which can be explained by a continuous solidification of4He on the surface of graphite in a layer-by-layer mode in the van der Waals field of the substrate. Moreover, we found a hysteresis behavior of the isopycnals, probably due to defect states in the solidified film. The thickness of the solid film is estimated by means of a simple solidification model. The neutron diffr…
Measurements of the volume and density of intracerebral tumors by CT following therapy.
1982
For the interpretation of curative measures in patients with cerebral tumors CT is of increasing importance. The therapeutic effects can be demonstrated by close follow-up studies without any of the disadvantage of invasive neuroradiological methods. Our investigations of 125 patients with cerebral tumors are based on volume and density determinations. The CT studies of removed or inoperable tumors followed by radiation and/or cytostatic therapy prove that the best results follow a combination of both. In the present cases however, if CT proves postoperatively, at the end of radiation or at the beginning of the application of cytostatics that there is a residual mass, a complete remission c…
The regional planning of sociosanitary services: methodologies and techniques of analysis
1982
In the field of sociosanitary planning, procedures have often, been fragmentary and disorganized, and the instruments of analysis and forecasting rudimentary. The utilization of models offering those who have to take the decisions an organized approach to the problem therefore represents an obligatory attempt, although there is some disagreement over the utility of their use. Accordingly, in order to understand and describe the mechanisms of the complex set of interacting elements that make up the sociosanitary services, and also to identify opportune means of intervention, this work gives an account of some general principles that make it possible to face problems of organization and contr…
Glass capillary gas chromatography of chlorinated methyl acetates, propanoates and butanoates on Carbowax 20M and SE-30 columns
1982
The gas chromatography of all chlorinated methyl acetates, methyl propanoates and methyl mono- and dichlorobutanoates has been studied on Carbowax 20M and SE-30 glass capillary columns under various running conditions. The order of elution on a non-polar column was largely determined by the boiling point of esters, whereas on a polar column it was much influenced by the structure of compounds. Complete separation of the combined mixture of all 27 compounds could not be achieved, however, methyl 3,3-dichlorobutanoate was the only ester overlapped on both columns in spite of the various column temperatures used. The best separation of the mixture was on Carbowax 20M with a temperature program…
Effects of beta-adrenoceptor drug stimulation on various models of gastric ulcer in rats.
1982
Abstract 1. Experiments were designed to evaluate the effect of the pharmacological activation of beta-adrenoceptors on various models of gastric ulcer in the rat. 2. Pretreatment with the beta-adrenoceptor stimulant drugs, isoprenaline or salbutamol, significantly inhibited stress-induced gastric ulcers. This anti-ulcer effect was abolished by propranolol but not by atenolol, suggesting that beta 2-adrenoceptors mediate this response. 3. In the pylorus-ligation model, salbutamol inhibited lesion formation and reduced the intragastric content of hydrogen ions, histamine and pepsin although the latter was only affected with the higher dose of salbutamol. 4. Salbutamol also prevented the ulce…
The (γ, n) reaction on 16O between giant resonance and pion threshold
1982
Abstract A new TOF facility has been built for measurements of differential (γ, n) cross sections to discrete final states of light nuclei in the photon energy range between giant resonance and pion threshold. The observed neutron angle θn can continuously be varied between 0° and 150°, and additionally measurements at 175° and 180° are possible. Differential cross sections for the reaction 16O(γ, n0)15O are presented for Eγ = 60 MeV (40° ⩽ θn ⩽ 149°) and for θn = 90° (60 MeV ⩽ Eγ ⩽ 160 MeV). The results, combined with the corresponding (γ, p0) cross sections, indicate an absorption mechanism of high energy photons by neutron-proton pairs.
The effect of physostigmine on the vagally induced muscarinic inhibition of noradrenaline release from the isolated perfused rabbit atria.
1982
1. Presynaptic cholinergic-adrenergic interactions were studied on isolated perfused rabbit atria with the extrinsic right vagus and sympathetic innervation intact. The transmitter stores were labelled with 14C-choline and 3H-noradrenaline. The radioactive compounds were separated on columns and determined by scintillation spectrometry. The stimulation-evoked overflow of both transmitters was calcium-dependent and abolished by tetrodotoxin. 2. Methacholine caused a concentration-dependent decrease of atrial tension development and 3H-noradrenaline overflow evoked by 3 Hz sympathetic stimulation. Vagus nerve stimulation (1–20Hz), although nearly abolishing tension development at 20Hz, decrea…
Youthful smoking and drinking in a longitudinal perspective.
1982
The incidence and continuity of smoking and drinking, precursory social-behavioral characteristics of smokers and drinkers, and life conditions related to smoking and drinking are described. The study was part of an extensive Finnish longitudinal study of social development, the original sample of which consisted of 8-year-old subjects (196 boys, 173 girls) studied in 1968 by employing peer nomination and teacher ratings. The follow-up studies were made at ages 14 and 20. 154 Ss at age 14 and 135 Ss at age 20 were interviewed about their smoking and drinking habits, among others. The results showed that about 20% of the subjects smoked at age 14 and about 30% at age 20. The proportion of ab…
Synthese und Reaktionen der 3-O-Phosphoniogluco-und -allofuranosen
1982
Aus den bicyclischen Gluco- (3, 5, 7 und 9) und Allofuranosen 11 werden mit Triphenylphosphan (1), Azodicarbonsaure-diethylester (2) und Alkylierungs- oder Acylierungsmitteln isolierbare 3-O-Phosphoniokohlenhydrate (4, 6, 8, 10 und 12) hergestellt. Durch Erwarmen der allo-konfigurierten Salze 12 konnen an C-3 epimere gluco-konfigurierte Substitutionsprodukte in groser Vielfalt gewonnen werden. Die Reaktionen der gluco-konfigurierten Salze werden stark vom Charakter des einzufuhrenden Nucleophils und von Nachbargruppen im Kohlenhydratgerust beeinflust. Wahrend das Iodid 4a und das Azid 4g unter Substitution zum allo-Derivat 15 reagieren, tritt in den Fallen mit Bromid, Chlorid oder Sulfonat …
Stoichiometric and kinetic study of the 99Tc-DMSA complex obtained with stannous excess: A possible model for the physico-chemical behaviour of the r…
1982
A stoichiometric and kinetic study was made of the 99mTc-DMSA complex obtained in the presence of large amounts of Sn2+. It is demonstrated that the Tc oxidation state is 3+. It is established that the complex degrades to another one if there is an Sn2+ deficiency. These results were confirmed by spectroscopic and spectrophotometric methods.
Analyse économique du travail temporaire
1982
référence interne : 82008
VISUAL BIASES IN TELEVISION CAMPAIGN COVERAGE
1982
Based on the results of an interrogation of cameramen who were considered experts for the application of camera techniques, a content analysis of camera positions in presenting the two candidates for the office of the Chancellor of the Federal Republic of Germany in the 1976 election was carried out. In addition, all verbal statements by journalists on positive and negative reactions of the public toward the two candidates as well as the optical display of positive and negative reactions were analyzed. Visual biases could be found evaluating the application of camera techniques by judgments of cameramen and confronting verbal and visual contents of television campaign coverage.
Ultrastructure of vascular neoplasms
1982
Summary The vascular tumors are morphologically recognized by their ability to configurate complete or atypical angiomatous structures. Based on our personal experience of 42 cases of benign and malignant angiomatous tumors, we discussed several aspects of their histogenesis and its morphology when studied with transmission and scanning electron microscopy. Therefore, a survey of the normal histology was developed based not only on normal adult histological structures but also on reparative tissues, as in chronic inflammatory reactions of the gingival mucosa, regenerative tissue of wounds and in chronic osteomyelitis. Supported by morphological arguments, we postulate the existence of sever…
Homomorphs and wreath product extensions
1982
A homomorph is a class of (finite soluble) groups closed under the operation Q of taking epimorphic images. (All groups considered in this paper are finite and soluble.) Among those types of homomorphs that have found particular interest in the theory of finite soluble groups are formations and Schunck classes; the reader is referred to (2), § 2, for a definition of those classes. In the present paper we are interested in homomorphs satisfying the following additional closure property:(W0) if A is abelian with elementary Sylow subgroups, then each wreath product A G (with respect to an arbitrary permutation representation of G) with G ∊ is contained in .
The pia mater at the site of the entry of blood vessels into the central nervous system
1982
The entry of blood vessels into the central nervous system (CNS) has been studied at the surface of the brain stem and the spinal cord of two cats and two rabbits. The study was carried out by scanning electron microscopy (SEM). The results obtained by SEM concerning the layers of the pia mater corresponded to those obtained by other authors who used transmission electron microscopy. Between the basal lamina of the superficial glial membrane of the CNS and the cells lining the subarachnoid space, a pial connective tissue space could be clearly recognized. The blood vessles crossing the subarachnoid space were also covered by leptomeningeal lining cells. At the site of entry of these blood v…
Oxygen-carrying v. non-oxygen-carrying colloidal blood substitutes in schock
1982
Loss of more than 10-15 per cent of the circulating blood causes a corresponding fall in filling pressure and a marked reduction in minute volume. In order to combat a fall in the minute volume, catecholamines are liberated, the stimulating components of these cause a rise in vessel tone. In spite of the blood volume being reduced by blood loss, filling pressure and minute volume are restored by compensating mechanisms as long as the volume lost is not enough to exceed the autoregulative capacity. Even with a blood loss of 10-15 per cent, full compensation is not achieved without replenishing the blood volume unless the fluid lost from the vascular bed is less than I0 per cent of the total.…
Lysosomal changes related to ageing and physical exercise in mouse cardiac and skeletal muscles.
1982
Physical exercise increased the activities of arylsulphatase, cathepsin D and β-glucuronidase in mouse skeletal muscle but not in cardiac muscle. Exercise-induced lysosomal response was more prominent in young adult than in senescent mice. The lipofuscin content of cardiac and skeletal muscles increased markedly during ageing and was also found to increase slightly after exertion in young mice, but not in senescent ones.
Studies on the mechanism of PMN activation II. by triggering the alternative pathway of complement activation
1982
By means of cobra venom factor (CVF) it is demonstrated that the stimulation of hexosemonophosphate shunt (HMPS) of human polymorphonuclear leukocytes (PMN) by zymosan (Z) and dextran sulfate (DS) is caused by at least two modes of activation: (a) via activation caused by phagocytosis, (b) via activated alternative pathway of complement activation (APC). Active factors of APC presented with phagocytizable objects strongly enhance activation of PMN. The effect of APC can be observed in serum-containing as well as in serum-free cultures. It can be demonstrated that in serum-free cultures the factors of APC participating in the activation of PMN are supplied by monocytes. By the use of synthet…
Effects of sorbinicate and nicotinic acid on blood viscosity, red cell deformation and platelet function
1982
Summary Nicotinic acid (NA) and a retard derivative, sorbinicate, were investigated for their effects on blood rheology and platelet function, after oral administration, in two groups of patients with lower limb atherosclerosis obliterans — the second group having diabetes also. Red cell deformation and blood plasma viscosity were studied in the nondiabetic group (single dose of NA, 100 mg, and sorbinicate, 400 mg); release of platelet malondialdehyde (MDA) (single dose of NA, 100 mg, and sorbinicate, 800 mg), and the platelet regeneration time (before and after sorbinicate 400 mg × 3/die for 7 days) were studied in the diabetic group. Both drugs induced a significant improvement in red cel…
Simple equipment to measure biomechanical quantities of muscles and organs which includes a polarity-programmable peak detector
1982
Biomechanical measurements of muscles and organs require appropriate measuring equipment. As far as the static properties are concerned, the excursion of the bender bar of stress should be without force. The bender bar of force, however, ideally should not elongate under load. Because natural frequency is the most important boundary condition, the bender bar should be developed with this in mind. The developed bars imposed an insignificant preload to the muscle or to the organ. The small changes in resistance occurring in the resistance strain gauges affixed to the bars require the use of a highly stable amplifier. A new amplifier was accordingly developed based on the principle of an instr…