showing 36 of ~574560 from 574555 documents
Mössbauer study of properties and phase transitions of Cd2Nb2–2xSn2xO7–2xF2x
1973
With the aid of Mossbauer spectroscopy the solid solution series Cd2Nb2–2xSn2xO7–2xF2x are investigated in the temperature range 4.2 to 400 K. The crystal structure belongs to the cubic pyrochlore type. The BY6 octahedra (B = Nb, Sn; Y = O, F) are linked three-dimensionally through their corners, forming groups of four octahedra which are extended or compressed in the (111)-direction for x ≤ 0.375 or x ≥ 0.400 respectively. The dependence of the quadrupole splitting ΔEQ on x shows a small but significant discontinuity in the region 0.375 < x < 0.400. This can be attributed to a first order phase-transition which depends on concentration, but not on temperature over the temperature region st…
Eine blockierungsmethode zur darstellung molekular-einheitlicher hydroxyphenylenmethylen-verbindungen
1973
Hydroxyphenylenmethylen-Verbindungen wurden nach verschiedenen Verfahren dargestellt. Dabei wurden folgende Ausgangsprodukte verwendet: p-Kresol und Formaldehyd (Gl. (i)) oder p-Kresol und 2,6-Bis(hydroxymethyl)-p-kresol (4) (Gl. (ii)), (Duplikations-Verfahren), 2-Chlor-6-(3′-chlormethyl-2-hydroxy-5′-methylbenzyl)-p-kresol (5) und 2-Chlor-p-kresol (Gl. (iii)), (schrittweise Synthese) oder 2-Chlor-6-chlormethyl-p-kresol (8) und p-Kresol (Gl. (iv)) (Blockierungsmethode). Die nach den verschiedenen Methoden entstandenen Reaktionsprodukte wurden papierchromatographisch aufgetrennt und identifiziert unter Berucksichtigung der bei der Analyse auftretenden Nebenreaktionen. Hydroxyphenylene methyle…
H�ufigkeit von Fettstoffwechselst�rungen bei asymptomatischen und manifesten Diabetikern
1973
Bei insgesamt 400 Diabetikern — 34 asymptomatischen und 366 manifesten Diabetikern — wurden Triglycerid- und Cholesterinwerte bestimmt sowie eine Lipidelektrophorese durchgefuhrt. Etwa 60% aller Patienten zeigte ein pathologisches Lipoproteinmuster. Um mogliche Einflusse auf begleitende Fettstoffwechselstorungen bei Diabetikern herauszufinden, wurden verschiedene Parameter, wie Dauer der Erkrankung, Lebensalter der Patienten, Einstellungsqualitat des Diabetes und das Korpergewicht der Patienten mit der Verteilung der Lipoproteinmuster in Beziehung gebracht. Auffallend war, das die Typen II (a und b) und IV nach Fredrickson mit etwa 24% gleich haufig bei allen Patienten vorkamen. Die Haufigk…
Helium-jet transportation of recoil atoms into a liquid phase
1973
Abstract A rapid inexpensive method has been developed for transportation of recoiling short-lived radioactive nuclides from a target chamber over distances of several meters into a liquid phase. This allows rapid radiochemical separation of different elements. The carrier-loaded helium-jet transport technique is employed without a pumping system. The method would appear to be applicable to most chemical elements. The transport efficiency is higher than 50% and the transport time can be made much shorter than 1 s. Radiochemical separation times of a few seconds were achieved.
Photoproduction of high-energy neutrons in thick targets by electrons in the energy range 150 to 270 MeV
1973
Photoneutron spectra with energies greater than 12 MeV produced by electrons incident on a thick lead target have been measured for primary electron energies between 150 and 266 MeV and at a fixed angle of 90 ° to the beam axis. Measurements of the neutron yield have furthermore been performed at a primary energy of 234 MeV as a function of target depth for the same lead target and as a function of the mass number for C, Al, Cu, Cd and Pb targets. The results were obtained with three independent neutron detectors: two proton recoil counters and one time-of-flight set-up. The high-energy regions of the spectra are compared with the predictions of the phenomenological quasi-deuteron model and…
Corrections for positon annihilation in flight in nuclear spectrometry
1973
Abstract Theories of positon single- and two-quanta annihilation in flight, the Fermi beta-decay theory, and theories of positon energy loss are used in calculations of total probabilities of annihilation in flight of positons in continuous spectra. The results are given in a nomogram useful in correcting for positon annihilation in flight in various nuclear-spectrometry experiments. Confirmation of the theoretical basis employed was obtained by comparing total absolute probabilities for annihilation in flight of 62 Cu positons in Perspex, copper, cadmium and lead, using a new differential method. The agreement with the theory was found to be excellent. A method for obtaining “correct” posi…
Kernresonanz- und Röntgenkleinwinkelmessungen an Polyäthylenoxid-Einkristallen
1973
Systematics of neutron emission probabilities from delayed neutron precursors
1973
A simple correlation based on the gross theory ofβ-decay is derived between the neutron emission probabilitiesPn of delayed neutron precursors, theirβ-decay energies and the neutron binding energies of the daughter nuclei. The correlation is shown to be valid for delayed neutron precursors among the fission products. ThePn-values of several expected but still unidentified neutron precursors are estimated together with their contributions to the delayed neutron groups in thermal-neutron induced fission of235U. Some aspects of theβ-strength function for transitions into highly excited states are discussed.
Les erreurs de mesure dans les modèles de régression
1973
Das „Hart-Weich-Konzept von Pearson” als Wegweiser zur Auffindung von Inhibitoren der Korrosion des Eisens
1973
Nach Pearson werden die Lewis-Sauren oder -Basen mit hoher Elektronegativitat und niedriger Polarisierbarkeit als „harte”, die mit niedriger Elektronegativitat und hoher Polarisierbarkeit hingegen als „weiche” Reaktionspartner bezeichnet. Reaktionen finden dabei bevorzugt entweder zwischen harten oder zwischen weichen Partnern statt. Der harte Charakter nimmt dabei mit zunehmender Valenz zu. Auf der Grundlage dieser Konzeption kann man die lnhibierungswirkung von Onium-Verbindungen in sauerstofffreien Sauren und die Wirkung gewisser Salze von Carbonsauren, Phosphaten u. a. in neutralen Salzlosungen deuten. Im ersten Fall handelt es sich um weiche Verbindungen, im zweiten um harte. Man kann …
Is the PGM1 locus subject to selection?
1973
The placental phosphoglucomutase phenotypes controlled by the first locus of 235 German and 119 non-German samples were determined. Both in the pooled material and in the sample containing German subjects only there was a significant deviation from the expected Hardy-Weinberg equilibrium. A segregation analysis of 1174 families also revealed significant deviations in the phenotypes of the children, though the mating frequencies were as expected. The distribution of the children's phenotypes deviated significantly from Hardy-Weinberg equilibrium though this was not found in the parent samples. The results are discussed.
Influence of therapeutic and toxic doses of neuroleptics and antidepressants on energy metabolism of the isolated perfused rat brain.
1973
The isolated perfused rat brain was used for a comparative study of the effects of promazine, imipramine, monodesmethyl promazine and desipramine on cerebral energy metabolism. After perfusion for 30 min or 1 h the brain levels of the following substrates and metabolites were estimated: P-creatine, creatine, ATP, ADP, AMP, glycogen, glucose, glucose-6-P, fructose diphosphate, dihydroxyacetone-P, pyruvate, lactate, α-ketoglutarate, and ammonia. Drug concentrations of 5·10−6 M and 10−5 M in the perfusion medium caused a significant decrease of glucose-6-P alone. When the drug concentration was raised to a toxic range (10−4 M), reflected in the EEG by the pattern of secondary discharges, an ac…
A simple method for filtering pump fluid vapors from circulated helium
1973
Abstract A simple efficient ceramic filter has been introduced for separation of oil vapors from circulated helium. Oil vapors were observed to pass easily through standard cold-trap and zeolite filters. They behave in these filters in the same way as “carrier fragments” behave in the helium-jet recoil-transport method. The significance of this observation is discussed.
L'impiego della celioscopia nel trattamento per via combinata delle sinechie uterine
1973
Zentralisatoren zentraler involutionen in $L_{n}(2)$
1973
Spurious Singularities in Quasipotential Amplitudes
1973
An aggression machine III. The stability of aggressive and nonaggressive patterns of behaviour
1973
PitkAnen, L. The stability of aggressive and non-agressive patterns of behaviour. Scand. Psychol., 1973, 14, 75–77.-Six extreme groups (overtly aggressive, aggressive-anxious, anxious, controlled extraverts, balanced controlled, and controlled introverts) had been composed on the basis of peer ratings. The differences between the groups were describable in terms of a two-dimensional model including the main dimensions “number of overt responses” and “control of behaviour”. Independent teacher ratings after an interval of one year showed that the individual patterns of behaviour adopted for coping with thwarting situations were maintained in spite of the change of class environment.
DNA-dependent DNA polymerase pattern in noninfected and herpesvirus infected rabbit kidney cells.
1973
In this paper we report on a DNA-dependent DNA polymerase produced in herpesvirus infected cells which is not present in virions. It differs from the polymerases of noninfected cells by its molecular weight as well as by its insensitivity to cytosine arabinoside triphosphate (ara-CTP).
Heavy isotopes of actinium: 229Ac, 230Ac, 231Ac and 232Ac
1973
Abstract By irradiation of 232Th with 150-MeV bremsstrahlung and with 14-MeV neutrons, three new neutron-rich isotopes of actinium, 230Ac, 231Ac and 232Ac, were produced and identified and the previously reported isotope, 229Ac, was confirmed. The actinium isotopes were chemically isolated by a fast procedure based on elution with α-hydroxyisobutyric acid from cation exchange resins. For 229Ac, a half-life of 62·7 ± 0·5 min and a β-ray energy of 1·14 ± 0·15 MeV were found; 35 γ-rays were observed, the strongest ones with the following energies and relative intensities: 135·3(34), 146·4(35), 164·6(100), 252·2(24), 261·9(39), 317·0(23), 539·9(20), 569·1(91), and 605·2 keV(23). For 230Ac, a ha…
Éducation et productivité
1973
International audience
Transport efficiency of the helium-jet recoil-transport method with pure helium
1973
Abstract New techniques have been developed for measuring the transport efficiency of the helium-jet recoil-transport method in the transport of radioactive recoil atoms. The dependence of the transport efficiency on main equipment parameters was studied experimentally using pure commercial-grade helium. The results are given in terms of helium mass throughput, capillary parameters and location of a catcher foil. High to moderate efficiencies were observed at transport distances shorter than 20 cm. Efficiencies obtained with pure helium at distances longer than 1 m are low, typically less than 1%. Possibilities for further development of the method are briefly discussed.
Meßverfahren zum Nachweis von plastischen Knochenveränderungen imµm-Bereich
1973
Fur moderne Kompressionsosteosyntheseverfahren ist die Reaktion des Knochens auf Druck sowohl an der Frakturstelle als auch an der Druckubertragungsstelle zwischen Implantat und Knochen von groser Bedeutung. Zur Aufrechterhaltung des Druckes, bei welchem an Knochen und Metall elastische Verformungen im µm-Bereich vorliegen, ist eine Unversehrtheit der Knochenstruktur Voraussetzung. Zur Uberprufung dieser Voraussetzung bei verschiedenen Druckubertragungsverfahren in verschiedenen Knochenabschnitten wurde eine Mesmethode mit cyclischer Wechseldruckbelastung entwickelt, mit welchem die plastischen Verformungen im µm-Bereich erfast werden konnen.
Neurobiologie und System-Theorie eines visuellen Muster-Erkennungsmechanismus bei Kröten
1973
Quantitative behavioral experiments have shown that the toad uses mainly two types of gestalt information in prey/enemy discrimination: pattern extension in the direction of movement promotes, in general, the signal value prey, while extension perpendicular to the direction of movement promotes that of enemy. Registrations from single fibers and single cells at different stages on the visual path showed that the object extension perpendicular to the direction of movement is chiefly analysed by means of the retinal and thalamus pretectal nerve nets, whereas the extension in the direction of movement is analysed mostly by certain tectal nerve nets. Further neurobiological findings indicated t…
Temperierte vektorwertige Distributionen und langsam wachsende holomorphe Funktionen
1973
An aggression machine I. The intensity of aggressive defence aroused by aggressive offence
1973
PitkAnen, L. An aggression machine. I. The intensity of aggressive defence aroused by aggressive offence. Scand. J. Psychol., 1973, 14, 56–64.-Sixty 9-year-old boys were tested with an aggression machine (PAM) designed by the writer. PAM allows the variation of both S (light) and R (pressing a button) intensities. The stimuli and responses were given the designations of offensive and defensive aggression, respectively. The following main hypotheses were supported: (1) The intensity of impulsive aggressive defence to an aggressive offence was adapted to the intensity of attack. (2) The intensity of aggressive defence was determined by the authority of the attacker, the defence being stronges…
Biological activity of 2-phenylethanol and its derivatives
1973
The biosynthesis of herpesvirus DNA in rabbit kidney cells is inhibited to 50% by PEA (2-Phenylethanol) at 0.65 mg PEA/ml. The inhibition of cellular DNA synthesis in uninfected cells by PEA is about twice as sensitive as that of viral DNA synthesis.
An aggression machine. II. Interindividual differences in the aggressive defence responses aroused by varying stimulus conditions.
1973
PitkAnen, L. An aggression machine. II. Interindividual differences in the aggressive defence responses aroused by varying stimulus conditions. Scand. J. Psychol., 1973, 14, 65–74.-The subjects, six aggressive and nonaggressive groups of ten 9-year old boys, selected by rating method, were tested with an “aggression machine” (PAM) constructed by the writer. The varying stimulus conditions included two situations of impulsive aggression and six variations of specified attackers. The results showed that (1) the larger part of the variance of the intensity of aggression in the PAM was accounted for by the situational variations than by interindividual differences in coping with thwarting situa…
Ability of the T cell-replacing polyanion dextran sulfate to trigger the alternate pathway of complement activation.
1973
Dextran sulfate (DS) consumed C3 in C4 deficient guinea pig serum. This temperature-dependent reaction required Mg++ ions and could therefore be blocked by EDTA. Isolated C3 was not influenced by DS, but serum factors were required for C3 consumption. The C3 proactivator as well as C3 were converted to their activated state by DS in guinea pig and human serum, as revealed by immunoelectrophoretical analysis. DS generated anaphylatoxin activity in serum. It is concluded that DS activates C3 via the alternate pathway of complement activation. This potency of the polyanion might serve as a tentative explanation for its T cell-replacing effect in an antibody-forming system, which was reported b…
Zur Tumorbildung bei Leukosen
1973
Es wird an Hand von 10 Fallen uber die Pathogenese und die Probleme der Diagnostik der Tumorbildungen bei Leukosen berichtet. Wahrend in den meisten Fallen ein ursachlicher Zusammenhang zwischen Therapie und Myelosarkom nicht nachweisbar ist, scheint der Splenektomie bei Polycythaemia rubra vera eine besondere Rolle zuzukommen. Die Identifizierung der haufig als retikulare oder lymphozytare Elemente bezeichneten Tumorzellen als leukotische Zellen gelingt mit einer kombinierten enzymhistochemischen und kunststoffeingebetteten Semidunnschnitt-Methodik.
On the existence of higher waves in a layer of superfluid helium
1973
The two implicit equations that contain the dispersion laws of waves propagating in a He II layer of variable thickness are formally investigated for solutions that go beyond those associated with the layer modifications of first and second sound: A series of symmetric and antisymmetric layer modes are found to exist by calculating the distribution of roots of the dispersion equations in the complex wave number plane as a function of layer thickness and angular frequency. All these modes turn out to be strongly attenuated and can be regarded as layer modifications of the viscous wave. Phase velocities, attenuation coefficients, and velocity profiles of some of them are calculated numericall…
Configuration mixing and total muon capture rates
1973
Abstract We modify the Primakoff closure approximation to get independence on the mean neutrino energy and energy weighted sum rules are used for the corrective terms. A near model - independent discussion is then possible, and the total rates are shown to be a very sensitive tool to investigate configuration mixing of the target. Wild discrepancies with experiment would arise if the limit of pure jj or LS couplings are used for 12 C, whereas the Cohen-Kurath wave function gives a very good result.
Synthesis of some derivatives of 4(1H)quinazolinones
1973
A new method for the in situ determination of phospholipids after thin-layer separation
1973
Abstract A very sensitive method has been devised for the in situ determination of phospholipids after thin-layer chromatographic separation, which enabled us to investigate the phospholipid content of erythrocytes and ATPase preparations. The phospholipid compositions of the ATPase preparations and of the erythrocytes are different, and the relative phospholipid compositions of the Na,K-ATPase preparations are also different, which indicates that Na,K- and Ca-ATPase seem to be different with regard to their phospholipid composition. An increase in temperature during the preparation procedure yields a Ca-ATPase preparation (II), which exhibits different kinetic properties and a different ph…
Gel permeation Chromatography in coiled columns
1973
Whereas in gas chromatography the use of coiled columns is the usual procedure, in liquid chromatography the use of straight columns is favoured. Bent columns give an additional contribution to peak spreading which is of greater importance in liquid chromatography than in gas chromatography owing to smaller diffusion coefficients. The low linear velocities of the mobile phase used in gel permeation chromatography enable conditions to be found where the additional contribution of bending to peak spreading is small. In the separation of oligomers, columns of 2-mm tube diameter and 20-cm coil diameter were used. With total lengths of 10 and 20 m, theoretical plate counts of ca. 70,000 and 150,…
The simple groups related to M24, II
1973
The objective of this paper is to prove the following generalization of the main result in [2]: THeorem. Let G be a finite simple group which possesses an involution t such that the centralizer of t in G is isomorphic to the centralizer of an involution in H. Then G is isomorphic to L5(2), M24, or H.