Showing papers by "Centre national de la recherche scientifique published in 1970"
TL;DR: α-amanitin selectively inhibits RNA synthesis catalyzed by calf thymus RNA polymerase activity B by interacting with the enzyme and inhibiting chain elongation as discussed by the authors, which can be used to identify the source of RNA synthesis.
449 citations
TL;DR: A new culture medium for cells from Drosophila embryos has been designed that has an osmotic pressure equivalent to 10.5 g per liter of NaCl, Na+: K+ ratio of 1.4, and very low Cl−.
Abstract: A new culture medium for cells fromDrosophila embryos has been designed. It has an osmotic pressure equivalent to 10.5 g per liter of NaCl (pH 6.7), Na+: K+ ratio of 1.4, and very low Cl−. Glycine and glutamic acid are high. Cells grow well for several weeks in this medium at 25–27°C and some cultures persist for months and establish euploid lines.
383 citations
TL;DR: On uncontaminated specimens, no structures were found which resembled the particulate material of natural membranes and neither degree of saturation, degree of hydration, nor cholesterol admixture significantly affects the appearance of lamellar fracture faces which appear uniformly smooth.
247 citations
TL;DR: In this article, the authors studied the second order kinetic energy of the fluorescence quencher Q − in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea.
219 citations
TL;DR: Different species of benthic Foraminifera taken at the same level in an Atlantic core yielded different oxygen isotopic values, so it was impossible to deduce paleotemperature values, an indication that pelagic andbenthic species reflect only the variation of oxygen-18 composition of the ocean.
Abstract: Different species of benthic Foraminifera taken at the same level in an Atlantic core yielded different oxygen isotopic values. It was therefore impossible to deduce paleotemperature values. In addition, pelagic and benthic species showed the same isotopic variations, an indication that pelagic and benthic species reflect only the variation of oxygen-18 composition of the ocean.
192 citations
01 Jan 1970
TL;DR: In this article, a domaine de temperature dans lequel la premiere couche d'adsorption de gaz rares et de methane sur graphite passe par trois etats successifs au cours de its formation.
Abstract: Il existe un domaine de temperature dans lequel la premiere couche d’adsorption de gaz rares et de methane sur graphite passe par trois etats successifs au cours de sa formation. Il s’agit tres vraisemblablement d’etats « gazeux », « liquide » et « solide » bidimensionnels. Il y aurait donc analogie avec le cas tridimensionnel.
156 citations
TL;DR: In this article, the growth rate of isotactic polystyrene was measured in a wide range of temperature using an original technique involving self-seeding and an accurate temperature control.
Abstract: Spherulitic growth rate of isotactic polystyrene was measured in a wide range of temperature using an original technique involving self-seeding and an accurate temperature control. The data are analysed according to the theoretical treatment of surface nucleation put forward by Hoffman et al. The free energy changes during crystallization are evaluated using three approximations, whereas the contribution of the mass transport to the growth rate was derived on the basis of the free volume, or the configurational free energy approach. The critical comparison of the theoretical predictions with the experimental data leads to conclusions concerning the practical use, the reliability and limitations of the present theroretical concepts.
143 citations
TL;DR: A phenomenological theory of the magnetic properties of two-component alloys, one of whose components has a permanent magnetic moment, and the other an exchange-enhanced paramagnetic susceptibility, was presented in this article.
Abstract: A phenomenological theory is presented of the magnetic properties of two-component alloys, one of whose components has a permanent magnetic moment, and the other an exchange-enhanced paramagnetic susceptibility. The paramagnetic susceptibility, magnetic-ordering temperature, and magnetization at low temperature are discussed in terms of this theory, and the results obtained are applied to cubic alloys $A{\mathrm{Co}}_{2}$ between rare earth ($A$) and cobalt.
142 citations
TL;DR: The ratios maximal O2/standard O2, 6 to 7 about in the four rodents studied, are less than those for dog, horse and man.
132 citations
TL;DR: In this paper, the susceptibility of the isolated iron atoms follows a Curie-Weiss law with a temperature dependence of the initial susceptibility below 1.3 K, which is responsible for the important temperature dependence in very dilute Cu:Fe alloys.
Abstract: The magnetization of very dilute Cu:Fe alloys contains one term proportional to $c$ due to the isolated impurities and another proportional to ${c}^{2}$ which is attributed to nearly magnetic or magnetic pairs. The susceptibility of the isolated iron atoms follows a Curie-Weiss law $C{(T+{T}_{k})}^{\ensuremath{-}1}$ with ${T}_{k}=29$ K well below ${T}_{k}$. The ${c}^{2}$ term which is nearly saturated in 60 kOe at 1.3 K is responsible for the important temperature dependence of the initial susceptibility below ${T}_{k}$.
124 citations
TL;DR: In this article, the reflectivity spectra of ZnTe and ZnSe were studied experimentally and theoretically, and the theoretical calculations were done at an assumed temperature of 300\ifmmode^\circ\else\text degree\fi{}K.
Abstract: Reflectivity spectra of ZnTe and ZnSe are studied experimentally and theoretically. The measurements are made at 15 and 300\ifmmode^\circ\else\textdegree\fi{}K, and the theoretical calculations are done at an assumed temperature of 300\ifmmode^\circ\else\textdegree\fi{}K. Spin-orbit interactions are included in the empirical pseudopotential calculation of the electronic band structures for both ZnTe and ZnSe. The imaginary part of the frequency-dependent dielectric function, the reflectivity, and the derivative of the reflectivity are calculated. In addition, a direct comparison of the measured and calculated reflectivity is made. The calculated derivative of the reflectivity is compared with thermo-reflectance data. The electronic transitions causing the reflectivity peaks are identified.
TL;DR: In this article, the authors measured saccharin intake in rats after injection, by various routes, of ethanol and sodium chloride, and found that only intoxicating doses of ethanol decreased the intake.
Abstract: Saccharin intake was measured in rats after injection, by various routes, of ethanol and sodium chloride. Only intoxicating doses of ethanol decreased saccharin intake, the magnitude depending on t...
TL;DR: These findings suggest that the reduced self-selection of alcohol resulting from the administration of these drugs is not specifically alcohol-related, and the technique described offers a sensitive procedure for the assessment of unpleasant effects of drugs.
Abstract: Injections of p-chlorophenylalanine or n-butyraldoxime given after rats were first given a 10-minute drinking test with saccharin or ethanol solutions produced a learned aversion to these solutions. These findings suggest that the reduced self-selection of alcohol (preference) resulting from the administration of these drugs, reported by others, is not specifically alcohol-related. The technique described offers a sensitive procedure for the assessment of unpleasant effects of drugs.
TL;DR: In this paper, a general method of thermal analysis is presented, whose aim is to reduce at will pressure and temperature gradients inside the sample submitted to thermolysis, by controlling the sample temperature so as to keep constant a parameter related to the decomposition rate.
Abstract: A general method of thermal analysis is presented, whose aim is to reduce at will pressure and temperature gradients inside the sample submitted to thermolysis. The basic idea is to control the sample temperature so as to keep constant a parameter related to the decomposition rate. Attention is specially called on the case when the controlled parameter is pressure, which allows to monitor at the same time two parameters (pressure and decomposition rate). As an example, one apparatus is described, working in the pressure range between 20 and 10−3 torr. This method of Constant Rate Thermal Analysis (CRTA) appears to be specially suited for thermal analysis under controlled vacuum, for the preparation of well defined porous samples, and for the study of decomposition mechanisms.
TL;DR: The influence of osmotic pressure in the affective transformation of taste perception in the human after ingestion of glucose and saline is looked at.
Abstract: A GUSTATIVE sweet stimulus gives rise to a pleasant perception in fasting human subjects. The same stimulus will seem unpleasant after ingestion of a hypertonic glucose load1,2. What is the nature of the internal signal responsible for this shift in perception from pleasant to unpleasant? McCleary has shown a relationship between the osmolarity of the administered fluids and food intake and has suggested3 that satiety may be a result of extracellular dehydration. Other workers have also supported the importance of osmotic factors in alimentary behaviour and the close relationship between food and water intake5–7. We therefore decided to look at the influence of osmotic pressure in the affective transformation of taste perception in the human after ingestion of glucose and saline.
TL;DR: In this paper, a nonresonant linear radiofrequency field is applied perpendicular to the static field, and the Zeeman lines coalesce in some cases; new sideband resonances also appear.
Abstract: We have observed new effects in the Zeeman hyperfine spectra of ${\mathrm{H}}^{1}$ and ${\mathrm{Rb}}^{87}$ when a nonresonant linear radiofrequency field is applied perpendicular to the static field: The Zeeman lines coalesce in some cases; new sideband resonances also appear A theoretical explanation is given for these effects Some possible applications for atomic clocks and masers are considered
TL;DR: The opisthobranch mollusc, Navanax, is carnivorous and cannibalistic, and electrical coupling among the 10 cells plays a minor role in sudden pharyngeal contractions but that the dual electrical-chemical coupling with interneurons may be important in this respect.
Abstract: The opisthobranch mollusc, Navanax, is carnivorous and cannibalistic. Prey are swallowed whole by way of a sudden expansion of the pharynx. The buccal ganglion which controls this sucking action was isolated and bathed in seawater. Attention was focused upon 10 identifiable cells visible on the ganglion's rostral side. Two cells were observed simultaneously, and each was penetrated with two glass microelectrodes, one for polarizing the membrane and the other for recording membrane potential variations. The coupling coefficients for direct current flow and action potentials of several identified cells were tabulated. Attenuation was essentially independent of the direction of current flow, but depended upon the relative size of the directly and indirectly polarized cells. The attenuation of subthreshold sinusoidally varying voltages increased with frequency above about 1 Hz. The coupling coefficient for spikes was lower than for DC due to greater high frequency attenuation. There is considerable similarity in the spontaneous PSP's of all cells, which is not due to the electrical coupling but to input from a common source. The 10 cells were not chemically interconnected but some were electrically connected to interneurons which fed back chemically mediated PSP's. The feedback can be negative or positive depending upon the membrane potential of the postsynaptic cell. We conclude that electrical coupling among the 10 cells plays a minor role in sudden pharyngeal contractions but that the dual electrical-chemical coupling with interneurons may be important in this respect.
TL;DR: The authors found that the ambiguity was most often perceived when both interpretations of the sentence were true with respect to the picture, and response latencies were shortest when both interpretation were false, and that Ss who claimed to have seen the ambiguity before responding had longer latencies than those who claimed not to see the ambiguity, and these differences in processing were clear only in Ss' responses to their first ambiguous sentence.
TL;DR: It is concluded that at least a partial “derepression” of elastin synthesis may occur in such conditions and arguments in favor of the immunological theory of atheromatosis are discussed.
TL;DR: A hyperpolarizing synaptic potential observed in Aplysia neurones is shown to be the result of an increase in potassium permeability and a re-evaluation is made of the criteria used to implicate the activation of an electrogenic pump.
Abstract: A hyperpolarizing synaptic potential observed in Aplysia neurones is shown to be the result of an increase in potassium permeability. A re-evaluation is made of the criteria used to implicate the activation of an electrogenic pump.
TL;DR: For the normal spinel ZnFe2O4 one indicates colinear and non-colinear spin arrangements which are equally compatible with neutron diffraction powder intensities, observed at 4.2 K as discussed by the authors.
TL;DR: In this paper, a simple model is used to describe the magnetic properties of cobalt impurities in copper, which gives rise to a large susceptibility and a large electronic specific heat, varying as the square of the concentration.
Abstract: A simple model is used to describe the magnetic properties of cobalt impurities in copper. Isolated impurities are nonmagnetic with a high spin-fluctuation temperature. Isolated pairs of neighbor cobalt atoms are very nearly magnetic: This gives rise to a large susceptibility and a large electronic specific heat, varying as the square of the concentration $C$. At low temperatures, only the group of three (or more) cobalt atoms carries a magnetic moment.
TL;DR: How total protein of rat brain myelin is extracted by the use of sodium dodecylsulphate (SDS) and how these extracts are examined by electrophoresis on analytical polyacrylamide gels giving three predominant bands are described.
TL;DR: In this article, the meson-dominance model is used to estimate the cross sections for leptonic production of π, ϱ and A 1 mesons and total leptone cross sections using the mesonedominance assumptions.
TL;DR: Differences in various types of tumors correlated with histological diagnosis, may perhaps help to determine the degrees of malignancy of intracranial tumors.
TL;DR: Climate variations in the Quaternary have been described with some precision, in the range of 0 to 35,000 yr BP, by radiocarbon dating and by using the isotopic ratio 18O/16O to estimate temperature.
Abstract: CLIMATIC variations in the Quaternary have so far been described with some precision, in the range of 0 to 35,000 yr BP, by radiocarbon dating and by using the isotopic ratio 18O/16O to estimate temperature. The ratio was measured either in foraminifera1 for the marine environment, or in stalagmites2–4 for the continental environment.
TL;DR: In this paper, the authors discuss rationalization among the numerous methods for access to 2,5-anhydrides of aldoses and singles out sugar derivatives in this class with regard to their properties and utilization.
Abstract: Publisher Summary This chapter discusses rationalization among the numerous methods for access to 2,5-anhydrides of aldoses The chapter also singles out sugar derivatives in this class with regard to their properties and utilization In context to methods of formation, there are several methods that constitutes the access to the 2,5-anhydroaldohexoses These include deamination of aminoaldoses with nitrous acid, halogenolysis of halogenated derivatives, intramolecular displacement of sulfonates by the action of a base, and solvolysis of sulfonates In specific, deamination of aminoaldohexoses with nitrous acid constitutes the oldest method for formation of 2,5-anhydroaldohexoses It is noted that the results obtained by this method can be rationalized on a theoretical basis as a consequence of concomitant developments in certain other areas of organic chemistry The action of nitrous acid on a primary, aliphatic amine is a complex process and leads ultimately to formation of carbonium ion, which is nonsolvated and chemically activated The nature of the products, resulting from its decay is essentially determined by the conformation of the initial state
TL;DR: In this article, the authors describe the preparation of gels reticules with polystyrene and divinylbenzene, and show how the reticule reticulation can be achieved by copolymerization sequence.
Abstract: La preparation de gels reticules peut etre effectuee par copolymerisation sequencee anionique de styrene et de divinylbenzene, sous l'action d'un promoteur bifonctionnel, en milieu aprotique et en atmosphere inerte. Les gels sont caracterises par leur taux de gonflement maximum. La masse moleculaire moyenne du polystyrene «parent», la concentration globale de la solution, au moment de la reticulation, et la proportion de DVB mise en jeu constituent les trois parametres qui determinent la porosite et la structure meme du gel. On peut donc preparer a volonte des reticulats homogenes de porosites tres differentes.
Dans un tel gel la distribution des tailles des mailles est fort etroite; la synerese peut etre aisement evitee; la signification physique du «point de gel» est bien etablie. Ces trois proprietes de la reticulation anionique ne se retrouvent pas dans les gels prepares par voie radicalaire et justifient l'etude de ces gels.
Durch anionische Blockcopolymerisation von Styrol und Divinylbenzol unter Einwirkung eines bifunktionellen Initiators wurden vernetzte Gele hergestellt. Die Reaktion wurde in aprotischen Losungsmitteln und unter Argon-Atmosphare durchgefuhrt. Die Gele wurden durch ihren maximalen Quellungsgrad charakterisiert. Es wurde festgestellt, das die folgenden drei Parameter die Eigenschaften der Gele beeinflussen: das Molekulargewicht des linearen Polystyrols, aus dem das Gel hergestellt wird, die Konzentration desselben Polystyrols bei der Zugabe von DVB und die Menge des eingesetzten Divinylbenzols pro lebendes Kettenende. Man kann also auf diese Weise homogene Gele verschiedener Porositat synthetisieren. Im Unterschied zu radikalisch hergestellten Gelen ist bei den auf anionischem Wege erhaltenen Proben die Verteilung der Maschengrosen sehr eng, und der Gelpunkt hat hier eine physikalische Bedeutung. Auserdem ist es leicht, hier die Synarese auszuschalten.
TL;DR: In this article, the Mg electrode in aqueous solution using various potentiostatic techniques was studied and the steady state study indicated the presence of an oscillation phenomenon in the cathodic range of potential.