La classe de seconde: une étape décisive de la carrière scolaire

1993

International audience; L'objectif de cette recherche est d'analyser les processus d'orientation à l'issue de la classe de seconde en portant une attention particulière à la différenciation des comportements entre garçons et filles à côté des variables socio-démographiques classiques que sont l'âge et l'origine sociale. On s'est également intéressé au rôle spécifique, dans ces processus, des options suivies en cours de 2nde. L'analyse s'appuie sur une enquête qui permet d'analyser les choix d'orientation en fonction des acquis scolaires de fin de 3ème (mesurés sur la base des résultats aux épreuves communes du BEPC) et de la progression scolaire réalisée pendant l'année de 2nde. Cette reche…

Physiology and genetics of antibiotic production and resistance.

1993

Actinomycetes have the genetic capability to synthesize many different biologically active secondary metabolites and of these compounds, antibiotics predominate in therapeutic and commercial importance. Intensive research often centres on the use of molecular techniques to investigate the physiology and genetics of antibiotic biosynthesis with a view to improving production. The isolation of clones of Streptomyces hygroscopicus, the producer of geldanamycin, which synthesizes geldanamycin in S. lividans, is reported. Molecular approaches using genes for elongation factors (tuf) were used in attempts to increase the fermentation yield of kirromycin, whilst probes for aphD and sph, genes for …

Kinetics of lactate fermentation and citrate bioconversion by LactococcusIactisssp.Iactisin batch culture

1993

The growth kinetics of Lactococcus lactis ssp. lactis were studied in batch culture in conditions of non-limiting lactose and the presence of citric acid. The control of pH modified growth and citrate metabolism but did not change the yield of acid formation. At controlled pH the growth rate was unaffected by citrate metabolism. Lactose was transformed to L-lactate and assay of the metabolic by-products showed some heterofermentation at the end of the growth of cultures with low growth rates. This heterofermentation was interpreted as a slowing down of glycolysis with activation of both the pyruvate formate lyase (PFL) and the pyruvate dehydrogenase complex (PDHC). Under these conditions th…

Calorimetric and viscosimetric investigation of the interaction between α,β-polyasparthydrazide and sodium dodecyl sulfate micelles

1993

Abstract The interaction between α,β-polyasparthydrazide (PAHy) and sodium dodecyl sulfate (SDS) micelles in aqueous solution was investigated by calorimetry and viscosimetry. The dependence of the enthalpic effect due to this interaction upon the surfactant concentration was rationalized in terms of a progressive binding of SDS micelles to the polymeric backbone. The analysis of the calorimetric data allow evaluation of the binding ability of SDS micelles to the polymeric chain. The viscosimetric behavior of SDS plus PAHy aqueous solutions, discussed in terms of the parameter F [F = ηrel(PAHy) + ηrel(PAHy) − ηrel(SDS+PAHy)], confirms the occurence of the interaction between SDS micelles an…

Cellular and subcellular distribution of receptors in the entorhinal—hippocampal system: Morphologic and biochemical aspects

1993

Mechanical properties-structure relationship in blends of polyamide 6 with γ-irradiated LDPE

1993

Blends of γ-irradiated and unirradiated low density polyethylene with polyamide 6 were made in order to study possible modifications induced by this irradiation. Blends with γ-irradiated polyethylene show structure and properties significantly different with respect to blends made with the unirradiated polyethylene. In this paper data on mechanical properties (tensile and impact) of these blends are presented. Results are related to the different morphologies in the blends.

Dynamic Aspects of Quasi-Particle Transfer in Molecular Electronic Devices

1993

Abstract The importance of the dissipative quantum dynamics of molecular systems for possible future device applications is emphasized. The necessity to study in detail the respective quasi-particle transfer phenomena is discussed. As a specific example charge transfer in a molecular dimer and a molecular chain is investigated in order to demonstrate how the quantum dynamical features can be controlled by different intrinsic nonlinearities.

5-Fluorouracil: various kinds of loaded liposomes: encapsulation efficiency, storage stability and fusogenic properties

1993

Abstract This paper describes the optimization of 5-fluorouracil (5-FU) loaded liposome formulations. Four different preparation procedures were carried out, obtaining two types of multilamellar vesicles (MLVs), stable plurilamellar vesicles (SPLVs) and large unilamellar vesicles (LUVs). In this study various phospholipids were used to prepare liposomes. The lipid mixtures containing diplamitoylphosphatidylserine seemed the best for biological 5-FU delivery by presenting better encapsulation efficiency parameters, serum and storage stability, and fusogenic properties, which are an important factor prerequisite for in vivo liposome-cell interaction. The presence of cholesterol in the liposom…

Synthesis and Crystal Structure of Ln3(OH)(CrO4)4 · 3.5H2O (Ln = Pr, Nd) and Ln2(OH)2(CrO4)2 (Ln = Tb, Gd): Thermal Behavior and Infrared Spectra of …

1993

Abstract Crystal structures of Ln 2 (OH) 2 (CrO 4 ) 2 ( Ln = Gd, Tb) and Ln 3 (OH)(CrO 4 ) 4 · 3.5H 2 O ( Ln = Pr, Nd) were determined by a conventional single-crystal X-ray diffraction technique. Crystals of Ln 2 (OH) 2 (CrO 4 ) 2 ( Ln = Gd, Tb) are monoclinic, space group P 2 1 / c (no. 14) with lattice parameters a = 8.2454(4) A, b = 11.3834(5) A, C = 12.1420(8) A, and β = 136,590(5)°, Z = 4, D x = 4.92 mg · m -3 for Gd 2 (OH) 2 (CrO 4 ) 2 and a = 8.214(1) A, b = 11.348(1) A, c = 12.094(2) A, and β = 136.59(1)°, Z = 4, D x = 5.01 Mg · m -3 for Tb 2 (OH) 2 (CrO 4 ) 2 . Crystals of Ln 3 (OH)(CrO 4 )) 4 · 3.5H 2 O ( Ln = Pr, Nd) are monoclinic, space group C 2/ c (No. 15) with lattice param…

Freely-Suspended and Transferred Freely-Suspended Films of Polymeric Liquid Crystals

1993

Freely-suspended (FS) liquid-crystal (LC) films of a polymethylsiloxane homo- and a copolymer with different mesogenic side groups have been prepared and investigated. For both substances the preparation of the films succeeded only in the isotropic phase but the higher ordered phases were reached after cooling. The films of the homopolymer have only been obtained with thicknesses estimated to be in the pm-range and with an unusual “Book-Shelf” orientation of the smectic layers. In contrast, the films of the copolymer were thinner and showed a homeotropic orientation of the mesogens in the smectic A phase. Interestingly, this material exhibited a different layer spacing in film and bulk, alt…

AM1 prediction of the equilibrium geometry of Si60

1993

Abstract AM1 calculations have been carried out to determine the equilibrium geometry of Si 60 . The predicted I h geometry shows that bonds may be clearly identified as single (2.297 A) or aromatic (2.092 A). Several analogies and differences between Si 60 and C 60 are pointed out. Especially remarkable is the bigger size of the Si 60 cluster, which is predicted to have a radius 2 A larger than that of the C 60 cluster. Results are compared to other levels of theory.

Processes during preparation of lead/acid battery positive plates from tetrabasic lead sulfate (4BS) pastes

1993

Abstract Tthe processes studied during this investigation were paste mixing and curing. Tetrabasic lead sulfate 4BS pastes were prepared by solution and paste methods both from α-PbO and mill oxides, and the development of 4BS was carried out already during the paste mixing stage. the 4BS pastes were characterized by SEM, TEM, XRD and wet-chemical methods, and the results were compared with those obtained from the characterization of corresponding tribasic lead sulfate (3BS) pastes. The preparation method was found to be one dominating factor affecting both the morphology and structure of 4BS active masses. The selection of raw material gave an additional effect on the morphology. Additiona…

Delayed maturation in plumage colour: Evidence for the female-mimicry hypothesis in the kestrel

1993

In many sexually dichromatic species, young males have female-like plumage during their first potential breeding year. The female-mimicry hypothesis (FMH) supposes that by possessing female-like plumage young males deceive older conspicuous males into believing that they are females, thus reducing competition from adult males. The status-signalling hypothesis (SSH) supposes that adult males can distinguish sex, but postulates that young males reduce competition from adult males by reliably signaling low status with their dull plumage. We tested these hypotheses in the European kestrel (Falco tinnunculus). Female-like young males settled to breed closer to adult males than did other adult ma…

Finite-size scaling and the crossover to mean-field critical behavior in the two-dimensional Ising model with medium-ranged interactions.

1993

Critical amplitudes in finite-size scaling relations show a singular dependence on the range of the interactions, R. The respective power laws are predicted from phenomenological crossover scaling considerations. These predictions are tested by Monte Carlo simulations for medium-ranged Ising square lattices. It is speculated that some deviations between the simulation results and corresponding predictions may be due to logarithmic corrections.

Induction of tumor-cell lysis by bi-specific antibody recognizing ganglioside GD2 and T-cell antigen CD3

1993

Human tumor cells expressing ganglioside GD2 were lysed by various effector populations targeted with an anti-CD3-anti-GD2 bi-specific antibody (BAb CD3 x GD2). This antibody-heteroconjugate was prepared by chemically cross-linking the OKT-3 monoclonal antibody (MAb) reactive with CD3 antigen on T lymphocytes with the ganglioside MAb ME 361, which binds preferentially to the tumor-associated ganglioside GD2. The specificity of target-cell lysis by the cytotoxic T cells (CTL) was mediated by the specificity of the targeting antibody: GD2-negative cells were not lysed in the presence of the CD3 x GD2 BAb. A dose-dependent response was observed in a range of 10 to 10,000 ng/ml. In contrast, 2 …

Observation of random-field behavior in (CO)1−x(N2)xmixtures physisorbed on graphite

1993

Heat-capacity studies have been carried out on submonolayers of (CO${)}_{1\mathrm{\ensuremath{-}}\mathit{x}}$(${\mathrm{N}}_{2}$${)}_{\mathit{x}}$ mixtures physisorbed on graphite. We find that pure CO undergoes an end-to-end ordering transition at ${\mathit{T}}_{\mathit{c}}$=5.18 K, which is shown to belong to the two-dimensional Ising universality class. In diluting CO with ${\mathrm{N}}_{2}$ the heat-capacity peaks become progressively rounded until the phase transition is completely suppressed at a ${\mathrm{N}}_{2}$ concentration of only x=0.07. The analysis of the data shows that this behavior is in quantitative agreement with predictions of the random-field theory applied to adsorbed…

UN ERRORE DIAGNOSTICO IN CHIRURGIA PEDIATRICA: La pielonefrite grantogranulomatosa ed il Tumore di Wilms

1993

The Authors report a case of Xanthogranulomatous Pyelonephritis characterized by a torpid course and clinical presentation of renal mass.

Les faunes des établissements ruraux de La Tène finale dans le nord de la France

1993

Méniel Patrice. Les faunes des établissements ruraux de La Tène finale dans le Nord de la France. In: Revue archéologique de Picardie. Numéro spécial 11, 1996. pp. 309-316.

Column-switching techniques for high-performance liquid chromatography of drugs in biological samples.

1993

In recent years, an increasing number of publications have demonstrated the potential of column-switching techniques for the chromatographic separation, determination and preparative isolation of analytes from biological matrices. Column-switching systems greatly facilitate drug analysis, by on-line sample clean-up and trace enrichment, or by improving the analytical separative process. In this paper, the main applications of column-switching techniques to drug analysis in biological samples, are reviewed.

A coupled model to simulate spectral reflectances, thermal infrared emission and microwave emission of a vegetation canopy

1993

National audience

Executive summary, overview, conclusions and recommendations

1993

National audience

Radiometric temperature response of soybean and corn leaves to water stress

1993

National audience

Caution. Liquidation judiciaire clôturée pour insuffisance d'actif, Art. 169 de la loi de 1985, Subsistance du droit de poursuite des créanciers cont…

1993

International audience; (Com. 8 juin 1993, Bonneau c/ Banque Nationale de Paris)

Arbitrage interne. Distinction entre l'arbitrage juridictionnel et l'arbitrage contractuel, Possibilité en droit français de confier le règlement d'u…

1993

International audience; (Paris, 24 mars 1992, Rev. arb. 1993. 278 ; Com. 9 avr. 1991, Bull. civ. IV, n° 139)

Regional specificities in the distribution, chemical phenotypes, and coexistence patterns of neuropeptide containing nerve fibres in the human anal c…

1993

Despite the pivotal clinical significance of the human anal canal, little is known about its total and specific innervation. This study assessed the comparative distribution and histotopology of nerve fibres immunoreactive for neural markers and a variety of regulatory active neuropeptides in the human anal canal by light microscopic immunohistochemistry. Depending on the epithelial zone and region of the anal canal, the neural elements were differentially immunoreactive for the pan-neural marker protein gene product 9.5, the catecholamine marker tyrosine hydroxylase, the neuroendocrine marker chromogranin A, and various neuropeptides. Protein gene product 9.5-immunoreactive nerve fibres we…

Application of an ectopic expression system for the selection of protein-isoform-specific antibodies. The monoclonal antibody K1 C3 is specific for t…

1993

Monoclonal antibodies were raised against a fusion protein consisting of a fragment of 141 amino acids of the C-terminal region of the rat brain voltage-gated K(+)-channel protein (RCK1) and the lambda N protein (fusion protein I). Selection of K(+)-channel-specific hybridoma cell lines was performed by means of an ELISA employing a fusion protein consisting of the K(+)-channel-specific peptide sequence and glutathione S-transferase (fusion protein II). For final selection of RCK1 isoform-specific antibodies, a panel of Xenopus oocytes was employed, each injected with cRNA coding for a specific RCK isoform (RCK 1, 2, 4 or 5). Several days after injection, cryosections of embedded oocytes we…

Arbitrage international. Arbitrabilité, Tribunal de commerce, Exception d'incompétence tirée de l'existence d'une clause compromissoire, Contrat liti…

1993

International audience; (Paris, 19 mai 1993, inédit, Soc. Labinal c/ Soc. Mors et Soc. Westland Aerospace Ltd)

Créancier hypothécaire. Liquidation judiciaire, Réalisation des immeubles, Sociétés de crédit immobilier, Application de l'article 140 du décret du 2…

1993

International audience; (Com. 9 juin 1992, SA Crédit immobilier du département de la Sarthe c/ Mme Brière et autre)

Déclaration des créances. Certification de sincérité à la charge du créancier, Mise en demeure du représentant des créanciers d'avoir à la fournir, D…

1993

International audience; (Paris, 12 nov. 1991, Consorts Guerrault c/ Soc. Codhor et autres ; Dijon, 15 déc. 1992, Signoles c/ SCP Bouillot et Deslorieux)

The role of histones and their modifications in the informative content of chromatin

1993

It is traditionally accepted that the DNA sequence cannot by itself explain all the mechanisms necessary for the development of living beings, especially in eukaryotes. Indeed part of the information used in these processes is stored in other ways, generally called ‘epigenetic’, whose molecular mechanisms are mostly unknown. The ultimate explanation for them might reside in the non-DNA moiety of chromatin which may play an active role in heredity (‘chromatin information’). Histones are the universal structural component of chromatin. However, recent studies strongly suggest that histones, and their modifications — especially the reversible acetylation of lysines — may act as a recognition s…

Vérification des créances. Irrecevabilité de l'appel du débiteur n'ayant pas soumis au représentant des créanciers sa contestation relative à une cré…

1993

International audience; (Com. 4 févr. 1992, Société immobilière d'investissement Marceau c/ Mizon ès qualité et autre)

Déclaration des créances. Absence du visa d'un commissaire aux comptes et de document justificatif, Validité (oui)

1993

International audience; (Com. 1er déc. 1992, Domaine de Malijay et autres c/ Banque Hottinger et autres)

Rovibrational interactions in the local-mode limit. The (n000) stretching overtone bands of spherical tops.

1993

New Studies and a Reinvestigation on [4+2] Cycloadditions of (−)-Thebaine: Asymmetrical Diels-Alder Reactions with a Conformationally Fixed Chiral Di…

1993

Some novel Diels-Alder reactions of the opium alkaloid (−)-thebaine (1) as an electron-rich diene and a reinvestigation of its reactions with cyclic and acyclic dienophiles are described. The π-facial selectivity has been studied on the basis of structural analyses of the cycloadducts. Some related results on [4 + 2] cycloaddition reactions of 1-methoxy-1,3-cyclohexadiene (11) are also reported.

Combretastatin Analogs via Hydration of Stilbene Derivatives

1993

Hydration of the double bond of some stilbene congeners of Picea abies bark by TiCl4·NaBH4 reagent is described. Five racemic 1,2-diphenylethanol derivatives (9–13), structurally related to (R)-(·)-combretastatin [(R)-1], have been obtained and characterized mainly by 13C- and 1H-NMR as well as mass spectrometry. The antileukemic activity of each compound has preliminarily been tested by the mouse leukemia L1210 system. Compound 10 has been synthesized by Friedel-Crafts acylation.

HLA-B27-restricted CD8 T cells derived from synovial fluids of patients with reactive arthritis and ankylosing spondylitis.

1993

Ankylosing spondylitis and seronegative spondylarthropathies such as Reiter's syndrome and reactive arthritis are strongly associated with HLA-B27. However, the mechanisms by which HLA-B27 is involved in disease susceptibility and pathogenesis are unknown. If the disease association is a consequence of HLA-B27's physiological function in antigen presentation, the disease should be mediated by cytotoxic T lymphocytes (CTLs) that recognise bacterial or self peptides presented by HLA-B27. Proof of this arthritogenic peptide model requires isolation of B27-restricted CD8 T cells from arthritic joints of patients with spondylarthropathies. An important question is whether "arthritogenic" bacteri…