Showing papers by "Centre national de la recherche scientifique published in 1971"
TL;DR: In this article, it was shown that increasing functions on a finite distributive lattice are positively correlated by positive measures satisfying a suitable convexity property, and applications to Ising ferromagnets in an arbitrary magnetic field and to the random cluster model were given.
Abstract: We prove that increasing function on a finite distributive lattice are positively correlated by positive measures satisfying a suitable convexity property. Applications to Ising ferromagnets in an arbitrary magnetic field and to the random cluster model are given.
1,131 citations
TL;DR: In this article, the authors derived infinitesimal generators of new field transformations which leave the action integral invariant, such as those obtained by Neveu and Schwarz, in the context of the functional integral formulation.
339 citations
TL;DR: In this article, it was shown that in YIG the magnetization in low fields is due to the same mechanisms for the whole temperature range to the Curie point, and that at a given temperature the magnetisation curves for different samples can be reduced to a single curve by taking into account the grain size.
Abstract: It is shown that in YIG the magnetization in low fields is due to the same mechanisms for the whole temperature range to the Curie point. At a given temperature the magnetization curves for different samples can be reduced to a single curve by taking into account the grain size. The interpretation is based on a model proposed earlier by Globus: the value of the reversible magnetization would be determined by the wall bulging, the value of the nonreversible magnetization by the wall displacement inside a spherical grain. For different temperatures a single reduced line is obtained by introducing the saturation magnetization and the effective anisotropy field, which is calculated from the susceptibility measured on a sample with single domain grains. So, it is possible to obtain a single magnetization curve which characterizes the composition.
228 citations
TL;DR: The properties of enterokinase suggest that it initiates the activation of trypsinogen which occurs in the duodenum, and appears to be a key enzyme of digestion since trypsinsin is responsible for theactivation of all of the other pancreatic zymogens.
205 citations
TL;DR: In this article, the diffusion coefficient of the crystallites is strongly temperature dependent, so that an activation enthalpy of migration can be defined, which is a function of the size of the crystal.
153 citations
TL;DR: In this paper, a semi-classical theory of Stark broadening is presented which differs basically from current theories and an exact solution is given using a model of the actual microfield incorporating all the essential information, i.e. the probability distribution and the covariance of the fluctuating microfield.
Abstract: A semi-classical theory of Stark broadening is presented which differs basically from current theories. No attempt is made to improve existing approximations. An exact solution is given using a model of the actual microfield incorporating all the essential information, i.e. the probability distribution and the covariance of the fluctuating microfield. Calculations can be carried out completely without approximations and no divergences are encountered. It is shown that the correct profiles are obtained in both the high- and low-density limit. Results are presented for hydrogen and helium lines.
148 citations
TL;DR: In this paper, the static electrical conductivity tensor of an electron gas in the presence of a magnetic field has been derived in the case of scattering by spinless (point) impurities, using a Green's function method.
140 citations
TL;DR: In this article, it was shown that in the zero-slope limit, the unitarized dual resonance model reduces to the φ 3 theory, where φ is a constant.
118 citations
TL;DR: In this paper, the thermal migration of small crystal buildings on a crystalline substrate is considered from two points of views: surface self diffusion of the atoms on the crystallites and special atomic configurations located in the interface crystallites-substrate are rendered responsible of these motions.
114 citations
108 citations
TL;DR: X-ray scattering experiments on native DNAs in solution show that very AT rich DNA has a different secondary structure from that of low and moderate AT content.
Abstract: X-ray scattering experiments on native DNAs in solution show that very AT rich DNA has a different secondary structure from that of low and moderate AT content. Unlike DNA of low and moderate AT content, DNA very rich in AT does not seem to adopt the B conformation.
TL;DR: It is inferred that the DNA helix is wound by 13 ° ± 4 °, and not unwound, as previously assumed, after the intercalation of one ethidium bromide molecule, which contradicts the conclusions derived previously from physical-chemical studies of closed circular DNA in solution, but agrees with X-ray diffraction results.
TL;DR: It is concluded that cardiolipin content of yeast is correlated with, and is a good indicator of, the state of development of mitochondrial membrane.
Abstract: The phospholipid composition of various strains of the yeast, Saccharomyces cerevisiae, and several of their derived mitochondrial mutants grown under conditions designed to induce variations in the complement of mitochondrial membranes has been examined. Wild type and petite (cytoplasmic respiratory deficient) yeasts were fractionated into various subcellular fractions, which were monitored by electron microscopy and analyzed for cytochrome oxidase (in wild type) and phospholipid composition. 90% or more of the phospholipid, cardiolipin was found in the mitochondrial membranes of wild type and petite yeast. Cardiolipin content differed markedly under various growth conditions. Stationary yeast grown in glucose had better developed mitochondria and more cardiolipin than repressed log phase yeast. Aerobic yeast contained more cardiolipin than anaerobic yeast. Respiration-deficient cytoplasmic mitochondrial mutants, both suppressive and neutral, contained less cardiolipin than corresponding wild types. A chromosomal mutant lacking respiratory function had normal cardiolipin content. Log phase cells grown in galactose and lactate, which do not readily repress the development of mitochondrial membranes, contained as much cardiolipin as stationary phase cells grown in glucose. Cytoplasmic mitochondrial mutants respond to changes in the glucose concentration of the growth medium by variations in their cardiolipin content in the same way as wild type yeast does under similar growth conditions. It is concluded that cardiolipin content of yeast is correlated with, and is a good indicator of, the state of development of mitochondrial membrane.
TL;DR: A comparison of the scattering for DNA and nucleohistone, and the scattering calculated from the B form, show that there is a family of structures of the B kind.
TL;DR: P-labeled native 5 s RNA from Escherichia coli was digested under mild conditions with T 1 or pancreatic RNases and the hydrolysate was analysed on an acrylamide gel slab in non-denaturing conditions and was resolved into a small number of discrete bands, which were eluted and characterized by fingerprints.
TL;DR: In this paper, the ESR technique has been used to study the localization of copper(II) ions in the zeolite framework, where the copper ion is in the form of an hexaaquo complex localized in the centre of the supercage.
TL;DR: R´sum´ Chez le Rat, la destruction bilate´rale du noyau ventro-me´dian de l'hypothalamus de´termine dans la plupart des cas une hyperre´activite´e´motionnelle, mais ne fait apparaiˆtre la re´action d'agressiona`l'e´gard de the Souris.
TL;DR: In this article, it was shown that if one restricts the form of the Lagrangian to bilinear form of fields, the kinetic term of the Langrarian is possible to construct only for conformal spin 0 and 12 fields.
TL;DR: In this article, the authors test the validity of standard physical approximations used in the theory of Stark broadening of atomic lines and conclude that the usual divergences at small and large impact parameters, which would also be present in the scalar model, arise from inadequate mathematical procedures (non-uniform asymptotic expansions), and not from the neglect of particle correlations, or from full quantum-mechanical effects.
Abstract: The purpose of the present paper is to test, on an exactly soluble model, the validity of standard approximations used in the theory of Stark broadening of atomic lines. The mathematical treatment involves no approximation; in particular, overlapping and incomplete collisions are correctly taken into account. In setting up the model, standard physical approximations are made: the dipole approximation, and uncorrelated perturbers with classical paths. In addition, in order to permit exact solution, the problem is taken to be scalar. As the exact solution shows no divergences whatsoever, it is concluded that the usual divergences at small and large impact parameters, which would also be present in the scalar model, arise from inadequate mathematical procedures (non-uniform asymptotic expansions), and not from the neglect of particle correlations, or from full quantum-mechanical effects, as often stated. The quasi-static and impact approximations are recovered as leading terms of asymptotic expansions of the line correlation function. The dominant role played by the probability distribution and the covariance of the microfield in determining the profiles of Stark-broadening lines is stressed.
TL;DR: The S‐ 100 protein fraction of pig and sheep brain was purified in 40 per cent yield by a modification of the procedure of Moore (1965), which avoided selective loss of S‐100 components.
Abstract: — The S-100 protein fraction of pig and sheep brain was purified in 40 per cent yield by a modification of the procedure of Moore (1965), which avoided selective loss of S-100 components. The S-100 fraction of both pig and sheep is a mixture of proteins as indicated by acrylamide gel electrophoresis and N-terminal amino acid analysis. Differences in amino acid composition, electrophoretic heterogenity and N-terminal analysis were found.
One fraction (fraction A) was isolated by DEAE-Sephadex chromatography from pig brain S-100 protein fraction. It was considered to be a single protein since it migrated as a single band on acrylamide gel electrophoresis and showed a single symmetrical peak during ultracentrifugal analysis. Only one N-terminal amino acid was detected in fraction A. The amino acid composition of this fraction showed minor but significant differences from that of the complete S-100 protein fraction from pig brain. The S-100 protein fraction of both species, as well as fraction A, had similar s20, w values and similar molecular weights (about 20,000) as indicated by gel filtration. These results, together with the immunological data obtained by other authors, suggest that the proteins of the S-100 fraction are closely related; the heterogeneity of the S-100 protein fraction may be of the same type as the lactate dehydrogenase isoenzymes.
TL;DR: This work has purified RNA polymerase B activity from rat liver in order to compare its components to those of calf thymus RNA polymerases B activity, and indicates that essentially the same components are present in both tissues, but do not exclude the presence of additional minor components in rat liver.
TL;DR: In this paper, a synthese du squalene et d'analogues est decrèce. André et al. propose a synthetse du qualene tritie a forte activite specifique.
TL;DR: Active transport across membranes is a typical membrane function, and it is felt that the elucidation of the detailed mechanism of this phenomenon might be highly relevant to the buildup of a realistic picture of membrane architecture and membrane function in general.
Abstract: Active transport across membranes is a typical membrane function, and it is felt that the elucidation of the detailed mechanism of this phenomenon might be highly relevant to the buildup of a realistic picture of membrane architecture and membrane function in general. The very first general membrane function is to serve as barrier against escape from the cell of essential molecules and against irruption into the cell of unselected molecules from the environment. This barrier function of the membrane has been studied thoroughly [31 ] since the end of the 19th century; its features helped establish the classical Davson-Danielli model of the membrane [7, 11, 35]. This model, in spite of growing dissent [40, 42], still dominates present thinking about membrane structure as testified by the recent success of the techniques of artificial lipid bilayers [1, 30]. In my personal opinion, the Davson-Danielli model, with some modification because of recent emphasis on hydrophobic interactions for the maintenance of native configuration of proteins in general [16], represents the quantitatively dominant membrane structure. This structure is inadequate to explain most phenomena of transport across membranes which often compel one to the view of proteins extending across the main hydrophobic layer of the membrane or of proteins moving across this layer, but it is possible to admit that functionally specialized minor spots interrupt the continuity of the impermeable layer of the membrane. The present controversy about membrane structure might be likened to a dispute between believers in the theory that a house is best described by a model of the walls and those who insist that the existence of doors and windows defeats the theory of the wall. The history of transport is relevant to doors and windows within the membrane. No membrane limiting a eell can exist without these channels
TL;DR: The test of colony growth inhibition of target tumor cells by host lymphoid cells in vitro was applied to study specific cell immunity in mammary tumor virus-free C3HeB/Fe mice to demonstrate specific immunological status during tumor growth and after surgical removal of the tumor, followed or not by other treatment.
Abstract: The test of colony growth inhibition of target tumor cells by host lymphoid cells in vitro was applied to study specific cell immunity in mammary tumor virus-free C3HeB/Fe mice. These mice bore neoplasms produced by inoculation of a cell line developed from a syngeneic spontaneous mammary tumor. Peritoneal washings were used as the source of lymphoid cells so that the mice could be checked periodically to Follow the evolution of their specific immunological status during tumor growth and after surgical removal of the tumor, followed or not by other treatment. As previously demonstrated in other host-tumor systems, peritoneal cells taken from animals at the beginning of tumor growth had a moderate, but significant, specific immunological activity which disappeared entirely when the tumors reached 7 mm or more in diameter. AFter surgical removal of the tumors, this activity reappeared but only after a delay of nearly 20 days. This delay could be significantly shortened if the animals were inoculated subcutaneously, 4 days after surgery, with their own tumor cells that had been trypsinbed, irradiated, and frozen.-j Nat Cancer lnst 46: 981-987, 1971.
TL;DR: In this paper, three phases with related structures are made in evidence at any composition; they are respectively monoclinic, orthorhombic and tetragonal with the rutile structure.
TL;DR: The results are very much in favour of the participation of −SH with processes related to the coupling mechanism, since the −SH increase upon addition of ADP + P i cannot be related to changes in the redox state of the respiratory chain or the phosphate entry.
TL;DR: In this article, a teste chez l'Homme l'evolution des reflexes monosynaptiques du triceps sural avant une contraction volontaire is described.
TL;DR: In this paper, the authors discuss relations exprimant les enthalpies libres d’exces de solution and les enthoupies libre d'exces d'activation du flot visqueux pour des melanges binaires.
Abstract: Nous avons etabli les relations exprimant les enthalpies libres d’exces de solution et les enthalpies libres d’exces d’activation du flot visqueux pour des melanges binaires.Le modele reticulaire simplifie a ete adopte; nous avons considere successivement le cas de solutions symetriques et de solutions associees.En general, pour des solutions symetriques, l’enthalpie libre d’exces d’activation est une traction changee de signe de l’enthalpie libre d’exces de solution, c’est le cas par exemple pour les systemes : thiophene-cyclohexane et benzene-aniline. La valeur du coefficient de proportionnalite « n » ne semble pas etre constante et egale a : n = 2,45 comme l’avait propose Eyring.Il a ete demontre que les mesures de viscosite peuvent mettre en evidence des faibles associations; cela se traduit par des viscosites d’exces positives alors que les enthalpies libres d’exces de solutions peuvent etre positives. De tels exemples sont fournis par les systemes pyridine-tetrachlorure de carbone et thiazole-tetrachlorure de carbone.
TL;DR: Three recessive mutations in mice result in grossly defective mye~ination in the central nervous system (CNS) while myelination of peripheral nerves is normal, and the PAPS-CST activities in the brains were greatly reduced while they were unchanged in the kidneys.