Showing papers by "Centre national de la recherche scientifique published in 1988"
TL;DR: In this article, the crystal structure of LiSbWO6 was solved from X-ray powder diffraction data and the structure was refined using Rietveld profile refinement principles.
2,325 citations
TL;DR: In this paper, the preparation of a colloidal colloidal by un procede sol gel is described, and a procedure for determination des proprietes electriques et electrochimiques is described.
2,040 citations
TL;DR: In this article, the authors consider scale invariant theories which couple gravity to Maxwell fields and antisymmetric tensor fields with a dilaton field, and they exhibit in a unified way solutions representing black hole, space-time membrane, vortex and cosmological solutions.
1,260 citations
TL;DR: It is shown that retinoic acid (RA) at physiological concentrations is effective in inducing the expression of an oestrogen-responsive reporter gene by the hap-ER chimaeric receptor, demonstrating the existence of two human retinoIC acid receptors designated RAR-α and R AR-β.
Abstract: We have previously described a human complementary DNA that encodes a novel protein which is homologous to members of the steroid/thyroid nuclear receptor multigene family. This novel protein (hap for hepatoma) exhibits strong homology with the human retinoic acid receptor (RAR) which has been recently characterized. To test the possibility that the hap protein might also be a retinoid receptor, a chimaeric receptor was created by replacing the putative DNA binding domain of hap with that of the human oestrogen receptor (ER). The resulting hap-ER chimaera was then tested for its ability to trans-activate an oestrogen-responsive reporter gene (vit-tk-CAT) in the presence of possible receptor ligands. Here we show that retinoic acid (RA) at physiological concentrations is effective in inducing the expression of this reporter gene by the hap-ER chimaeric receptor. This demonstrates the existence of two human retinoic acid receptors designated RAR-alpha and RAR-beta.
975 citations
TL;DR: A tentative general framework for change detection in signals and systems is presented, based upon a non-exhaustive survey of available methods, which are presented according to the increasing order of complexity of the change problem.
877 citations
TL;DR: There has been increasing interest in the eight members of the melanogaster species subgroup of Drosophila, but no comprehensive survey exists of the biogeography and ecology of these species in the Afrotropical region.
Abstract: Whereas there has been increasing interest in the eight members of the melanogaster species subgroup of Drosophila, no comprehensive survey exists of the biogeography and ecology of these species in the Afrotropical region.
628 citations
TL;DR: Results suggest that the hormone plays at least a dual role in chimeric receptors, and the hormone, or anti-hormone, is responsible for receptor "transformation" allowing the recognition of responsive DNA elements.
576 citations
TL;DR: A review of the current state of the art in turbulent combustion modelling can be found in this article, where the authors present physical and experimental knowledge of the structure of turbulent flames in order to help the further discussions of models on a physical basis.
572 citations
TL;DR: Drosophila melanogaster natural populations show considerable show considerable genetic variation in different geographic regions, which suggests that the evolutionary history of the species involved the spreading of ancestral Afrotropical populations through Eurasia and, more recently, to America and Australia.
513 citations
TL;DR: It is suggested that H1K and MPF are the same entity, and that histone H1 is likely to be one substrate of the pleiotropic MPF.
494 citations
TL;DR: Wu et al. as mentioned in this paper proposed a new three-dimensional structure of B-starch in which the unit cell contains 12 glucose residues located in two left-handed, parallel-stranded double helices packed in a parallel register; 36 water molecules are located between these helices.
Abstract: A new three-dimensional structure of B-starch is proposed in which the unit cell contains 12 glucose residues located in two left-handed, parallel-stranded double helices packed in a parallel register; 36 water molecules are located between these helices. Chains are crystallized in the hexagonal space group P61, with lattice parameters a = b = 1.85 nm, c = 1.04 nm. The space group symmetry was derived from an exhaustive analysis of the large body of structural studies published so far. Diffraction data used in this work were taken from the previously reported x-ray fiber diffractogram [H.C. Wu and A. Sarko (1978), Carbohydrate Research, 61, 7–25] after adequate reindexing. The final R factor is 0.145 for the three-dimensional data. The repeating unit consists of a maltose molecule where the glucose residues have the 4C1 pyranose conformation and are α(1 → 4) linked. The conformation of the glycosidic linkage is characterized by torsion angles (Φ, Ψ) that take the values (83.8°, −144.6°) and (84.3°, −144.1°), whereas the valence angles at the glycosidic bridge have a magnitude of 115.8° and 116.5°, respectively. The primary hydroxyl groups exist in a gauche–gauche conformation. There is no intramolecular hydrogen bond. Within the double helix, interstrand stabilization is achieved without any steric conflict and through the occurrence of O(2)…O(6) type of hydrogen bonds. The model presented here, with an hydration around 27% w/w, corresponds to a well-ordered crystalline sample, since all the water molecules could be located with no apparent sign of a disorder. Half of the water molecules are tightly bound to the double helices; the remainder forms a complex network centered around the sixfold screw axis of the unit cell. The consistency of the present structural model, with both physicochemical and biochemical aspects of the crystalline component of tuber starch granules, is analyzed.
TL;DR: In this article, the Deccan flood basalts were used to test the hypothesis that the flood basalt could be responsible for events observed at the Cretaceous/Tertiary boundary by studying the 40Ar/39Ar ages of samples.
Abstract: Courtillot et al.1 have presented palaeomagnetic, palaeontological and K–Ar data for the Deccan flood basalts which suggest that > 106 km3 of basalt may have been erupted in < 1 Myr, mostly in a reversed magnetic chron. This chron is argued to be 29R, the one which contains the Cretaceous/Tertiary boundary. Here we aim to test the hypothesis1–5 that the Deccan basalts could be responsible for events observed at the Cretaceous/Tertiary boundary by studying the 40Ar/39Ar ages of samples with a wide geographic distribution. Many samples have been altered too extensively to yield plateau ages, but we have made five successful determinations. Considered with earlier6 and concurrent7 results, our data confirm that the bulk of the Deccan eruptions occurred in a short time, between 65 and 69 Myr, probably coincident with the Cretaceous/Tertiary boundary.
Proceedings Article•
01 Jan 1988TL;DR: In this article, the design procedures used to characterize dielectric resonators and their applications in the millimeter-wave frequency band are discussed, focusing on low noise, small size, low cost and high temperature stability.
Abstract: Microwave passive and active devices containing dielectric resonators and the design procedures used to characterize these components are reviewed. The emphasis has been on low noise, small size, low cost and high temperature stability. Both filter and oscillator applications are described. The applications of dielectric resonators in the millimeter-wave frequency band are also discussed. >
TL;DR: The structures of Q230, Q224, Q229 and of Q212, Q227, Q223 are shown to provide topological generalizations of the two paradigms of lipid organization; namely, the bilayer and the monolayer.
TL;DR: A survey of nucleation, growth, phase transition, habit modification and ripening can be found in this paper, where the authors provide a theoretical basis to biochemists who intend to approach crystallization.
TL;DR: In this paper, the authors have used two indicators: the Rain Use Efficiency Factor (RUE) which is the quotient of annual primary production (kg DM/ha/year) by rainfall (mm/year).
TL;DR: In this article, a probabilistic model was developed that applies to the analysis of erratic movements made by animals foraging in a stochastic environment, and the main properties of the model were studied by numerical simulations using a pseudo-random generator.
TL;DR: It is proposed that FixL, which has features of a transmembrane protein, senses an environmental signal and transduces it to FixJ, a transcriptional activator of nif and fix genes.
TL;DR: Localized (exponentially decaying in all directions) soliton solutions of the evolution equations related to the Zakharov-Shabat spectral problem in the plane are explicitly given in this article.
TL;DR: The human oestrogen receptor when expressed in yeast stimulates initiation of transcription in a strictly hormone dependent manner, as in mammalian cells indicating striking conservation of the underlying regulatory mechanisms.
Abstract: The human oestrogen receptor when expressed in yeast stimulates initiation of transcription in a strictly hormone dependent manner, as in mammalian cells indicating striking conservation of the underlying regulatory mechanisms.
TL;DR: In this paper, the basic rules of quantum mechanics are reformulated and a proposition calculus is obtained, allowing in principle the replacement of the discussion of problems concerned with the practical interpretation of experiments by due calculations.
Abstract: The basic rules of quantum mechanics are reformulated. They deal primarily with individual systems and do not assume that every ket may represent a physical state. The customary kinematic and dynamic rules then allow to construct consistent Boolean logics describing the history of a system, following essentially Griffiths' proposal. Logical implication is defined within these logics, the multiplicity of which reflects the complementary principle. Only one interpretative rule of quantum mechanics is necessary in such a framework. It states that these logics providebona fide foundations for the description of a quantum system and for reasoning about it. One attempts to build up classical physics, including classical logic, on these quantum foundations. The resulting theory of measurement needs not to statea priori that the eigenvalues of an observable have to be the results of individual measurements nor to assume wave packet reduction. Both these properties can be obtained as consequences of the basic rules. One also needs not to postulate that every observable is measurable, even in principle. A proposition calculus is obtained, allowing in principle the replacement of the discussion of problems concerned with the practical interpretation of experiments by due calculations.
TL;DR: There is, remarkably, a complete identity of their cytoplasmic domains between the human and murine CTLA‐4 proteins and this complete interspecies conservation comes in support of an important role for this domain in CTla‐4 function.
Abstract: The mouse CTLA-4 gene has been shown to code for an activated lymphocyte-associated sequence belonging to the Ig gene superfamily. We now report on the molecular cloning and study of the human corresponding gene isolated from a genomic library and designated Hu-CTLA-4. The Hu-CTLA-4 gene exists as a single copy per human haploid genome and maps to band q33 of chromosome 2. It comprises 3 exons notwithstanding the leader sequence. The first exon encodes a V-like domain of 116 amino acids, the second one a hydrophobic putative transmembrane region of 37 amino acids and the third one a 34 amino acid putative cytoplasmic domain. Whereas the overall homology between the human and murine CTLA-4 proteins is 76%, there is, remarkably, a complete identity of their cytoplasmic domains. This complete interspecies conservation comes in support of an important role for this domain in CTLA-4 function.
TL;DR: Methods of studying bioadhesion are described as well as the existing bioadhesive dosage forms, which include polycarbophil a Carbopol 934, and low chemical bonds.
Abstract: Bioadhesion could lead to the solution of bioavailability problems resulting from a too short stay of the pharmaceutical dosage form at the absorption or activity level of the active ingredient. Bioadhesion stages are: intimate contact resulting from a good wetting of the bioadhesion surface and the swelling of the bioadhesive polymer, then penetration of the bioadhesive into the crevice of the tissue surface or interpenetration of bioadhesive chains with those of the mucus, and finally low chemical bonds. date, the most important bioadhesive polymers are polycarbophil a Carbopol 934. Methods of studying bioadhesion are described as well as the existing bioadhesive dosage forms.
TL;DR: A microscale colorimetric assay for neutral sugars, in which neutral sugars react with resorcinol in the presence of 75% sulfuric acid solution is described, which allows accurate determinations with small samples containing 1 to 100 nmol of neutral sugars and is quite convenient for detection of glycoconjugates in chromatographic column effluents.
TL;DR: This article reported thermoluminescence dates for 20 specimens of burnt flints recovered from the hominid-bearing layers of Qafzeh1 and Skhul2,3 caves in Israel have yielded the remains of over 30 hominids.
Abstract: The Qafzeh1 and Skhul2,3 caves in Israel have yielded the remains of over 30 hominids. Despite their association with Mousterian deposits, these have been recognized as forerunners of other Homo sapiens sapiens on morphological grounds and have been called 'Proto-Cro-Magnons'1. Other west Asian caves (Amud, Tabun, Kebara and Shanidar) have yielded skeletal remains of Neanderthals associated with similar Middle Palaeolithic deposits. The lack of precise dates for these deposits has made it difficult to ascertain which of the two hominids was present first in the area1'4–9. Recently we reported an age of ≈60 kyr for the Neanderthal burial at Kebara6 (Israel). Here we report thermolumines-cence dates for 20 specimens of burnt flints recovered from the hominid-bearing layers of Qafzeh1. The dates, which range from ∼90 to 100 kyr bp, provide an independent measure for the great antiquity of southwest Asian modern humans which have previously been dated to ∼40 kyr bp on the basis of European models7–9 . Our results also exclude a close phylogenetic relationship between the Cro-Magnons and Neanderthals1,4–6.
TL;DR: One Clostridium difficile strain (CD196) is found that is able to produce, in addition to toxins A and B, a new ADP-ribosyltransferase that was shown to covalently modify cell actin as Clostridgeium botulinum C2 or Clastridium perfringens E iota toxins do.
Abstract: By screening possible ADP-ribosyltransferase activities in culture supernatants from various Clostridium species, we have found one Clostridium difficile strain (CD196) (isolated in our laboratory) that is able to produce, in addition to toxins A and B, a new ADP-ribosyltransferase that was shown to covalently modify cell actin as Clostridium botulinum C2 or Clostridium perfringens E iota toxins do. The molecular weight of the CD196 ADP-ribosyltransferase (CDT) was determined to be 43 kilodaltons, and its isoelectric point was 7.8. No cytotoxic activity on Vero cells or lethal activity upon injection in mice was associated with this enzyme. CDT was neither related to C. difficile A or B toxins nor to C. botulinum C2 toxin component I. However, Vero cells cultivated in the presence of C. difficile B toxin had a lower amount of actin able to be ADP-ribosylated by CDT or C2 toxin in vitro. Antibodies raised against CDT reacted by immunoblot analysis with a 43-kilodalton protein of C. perfringens type E culture supernatant producing the iota toxin. Images
TL;DR: The data suggest that estrogen down-regulates ER mRNA by inhibition of ER gene transcription at early times and by a posttranscriptional effect on receptor mRNA at later times.
Abstract: The role of estradiol in the regulation of its cognate receptor in MCF-7 cells was investigated in this study. After treatment with 10−9 m estradiol, the level of receptor protein was measured using an enzymeimmunoassay. By 6 h, the receptor protein declined by about 60% from a level of approximately 3.6 to 1.2 fmol/μg DNA. The level of receptor remained suppressed for 24–48 h. Similar results were obtained with an estrogen receptor (ER) binding assay. The steady state level of ER mRNA was determined by an RNase protection assay. Estrogen treatment resulted in a maximum suppression of mRNA by 6 h. Receptor mRNA remained depressed for 48 h. Transcription run on experiments demonstrated a transient decrease of about 90% in ER transcription after 1 h. By 3–6 h transcription increased approximately 2-fold and remained elevated for at least 48 h. These data suggest that estrogen down-regulates ER mRNA by inhibition of ER gene transcription at early times and by a posttranscriptional effect on receptor mRNA at ...
TL;DR: Amino acid substitutions in evolutionarily related proteins have been studied from a structural point of view and the distance matrix determined in this study seems to be very efficient for aligning distantly related protein sequences.
TL;DR: In this article, the contributions of relativistic dynamical effects of order higher than the usual first post-Newtonian (1PN) equations of motion are investigated, and the spin-orbit contribution to the secular precession of the orbit in space is derived in a streamlined way by making full use of Hamiltonian methods.
Abstract: The contributions to the periastron advance of a system of two condensed bodies coming from relativistic dynamical effects of order higher than the usual first post-Newtonian (1PN) equations of motion are investigated. The structure of the solution of the orbital second post-Newtonian (2PN) equations of motion is given in a simple parametrized form. The contributions to the secular periastron advance, and to the period, of orbital 2PN effects are then explicitly worked out by using the Hamilton-Jacobi method. The spin-orbit contribution to the secular precession of the orbit in space is rederived in a streamlined way by making full use of Hamiltonian methods. These results are then applied to the theoretical interpretation of the observational data of pulsars in close eccentric binary systems. It is shown that the higher-order relativistic contributions are already of theoretical and astrophysical significance for interpreting the high-precision measurement of the secular periastron advance of PSR 1913+16 achieved by Taylor and coworkers. The case of extremely fast spinning (millisecond) binary pulsars is also discussed, and shown to offer an easier ground for getting new tests of general relativity, and/or, a direct measurement of the moment of inertia of a neutron star.
TL;DR: Addition of a 17-mer GAL4 binding site to the SV40 enhancer resulted in a synergistic enhancement of transcription in the presence of GAL 4, indicating that the molecular mechanisms responsible for transcriptional enhancement have been conserved from yeast to man.