Surface and interface analysis of worn TiN (PVD) coated cold forging tools

1992

Abstract Wear of cold forging tools, improved by TiN (PVD) hard coating and used in the production of alternator and starter components in the car industry, has been studied in detail. The most complicated case was the tool that produced a clutch housing of high precision. The 630 kN press process (50 pcs min −1 ) caused heavy adhesive and abrasive wear due to material flow, high surface pressure and also wear in the direction of tool movement. Results show that on the worn functional surfaces of the analysed tool, the lifetime of which was extended with TiN coating by a factor of 8–10, the following features were observed: non-uniform TiN coating thickness decrease; long grooves, damaged a…

Molecular tunneling and pumping effects in low temperature MBCO recombination

1992

Recombination of carbonmonoxide after photodissociation has been studied by Mossbauer spectroscopy at 4.2K and in the low temperature region, where tunneling effects play an important role in rebinding. We interpret the kinetic results in terms of a radiationless nonadiabatic multiphonon transition, which leads to a uniform description for all temperatures. Prolonged illumination at low temperature results in pumping into long-living states.

4,4′‐Distyrylazobenzol als Chromophor

1992

4,4′-Distyrylazobenzene as Chromophore 4,4′-Distyrylazobenzenes are prepared from 4,4′-dimethylazobenzene. Whereas the Siegrist method furnishes stereoselectively the (E,E,E) configuration, a Wittig olefination leads to a mixture of (Z,E,Z), (Z,E,E) and (E,E,E) isomers which can be easily separated. Irradiation of the intense absorption at λ ≈ 400 nm causes a selective (E) (Z) isomerization of the N = N bond of all three isomers. The reverse reaction takes part in the photochemical equilibration, moreover, it is a thermal process with a relatively low activation barrier.

Mössbauer spectroscopy on the reaction center of Rhodopseudomonas viridis

1992

Proteins called “reaction centers” (RC) can be isolated from many photosynthetic bacteria. They have one non-heme iron in a quinone acceptor region. The RC of Rhodopseudomonas viridis contains an additional tightly bound tetra-heme cytochrome c subunit. The electronic configuration of both cytochrome and the non-heme iron has been studied in the crystallized protein by Mossbauer spectroscopy at different redox potentials, pH-values, and with an addition of o-phenanthroline. At high potentials (Eh=+500mV) all heme irons are in the low spin Fe3+-state, and at low potential (Eh=−150mV) they are low spin Fe2+ with the same Mossbauer parameters for all hemes independent of pH. Redox titrations c…

Amyloidose des Knochens und der Weichteile nach einem Plasmozytom

1992

Chemically driven phase separation in black lipid membranes and its coupling to membrane functions

1992

Abstract We analysed the single-channel current fluctuations of gramicidin in bimolecular lipid membranes in order to demonstrate (i) the influence of protein binding to the lateral organisation of a mixed membrane, and (ii) how this couples to the function of the ionophore. Examples of phase separations induced by synthetic polyelectrolytes, as models for peripheral membrane proteins, and specific ligand-receptor interactions are presented and discussed in view of the important lateral order-function relationship in biomembranes.

Anti-HCV, anti-GOR, and autoimmunity

1992

Gaseous sensors based on solid proton conductors

1992

Abstract he chemical sensors for different gaseous (alcohol, acetone, ammonia, water vapour) detection at room temperature are developed by using polycrystalline β-alumina and xerogel of antimonic acid hydrate (AAH). The sensitivity and selectivity of sensors depend on the ion-exchange and preparative methods. The possibility of producing different types of potentiometric, amperometric, voltammetric and resistance sensors on the basis of these ion-conducting materials is shown. More success is achieved by producing ammonia-sensitive devices on β-alumina as well as on AAH xerogel.

A Nonlinear Approach to Brain Function: Deterministic Chaos and Sleep EEG

1992

In order to perform a nonlinear dimensional analysis of the sleep electroencephalogram (EEG), we applied an algorithm proposed by Grassberger and Procaccia to calculate the correlation dimension D2 of different sleep stages under Lorazepam medication versus placebo. This correlation dimension characterizes the dynamics of the sleep EEG and it estimates the degrees of freedom of the signal under study. We demonstrate that slow-wave sleep depicts a much smaller dimensionality than light or rapid eye movement (REM) sleep, and that Lorazepam does not alter the EEG's dimensionality except in stage II and REM.

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1992

Book Review: Preparative Polar Organometallic Chemistry 2. By L. Brandsma

1992

Star-free trace languages

1992

Abstract Generalizing a classical result of Schutzenberger to free partially commutative monoids, we prove that the family of star-free trace languages coincides with the family of aperiodic trace languages.

Separation of monoacylglycerols by reversed-phase high-performance liquid chromatography

1992

Abstract Reversed-phase high-performance liquid chromatography on a thermostated octadecylsilyl column was used to separate complex mixtures of monoacyglycerols formed by chemical deacylation of natural triacyclycerols. Acetonitrile-water mixtures were used for elution of the underivatized monoacylglycerols and a different refractometer was used for their detection. The order of elution of monoacylglycerols in complex mixtures varies as a function of the chain length, unsaturation, positional isomerism, analysis temperature and eluent water concentration. The peak areas were representative of the amounts of monoacylglycerols detected. The method can be applied to compositional analysis and …

A high-frequency survey of the southern Galactic plane for pulsars

1992

Results of an HF survey designed to detect young, distant, and short-period pulsars are presented. The survey detected a total of 100 pulsars, 46 of which were previously unknown. The periods of the newly discovered pulsars range between 47 ms and 2.5 ms. One of the new discoveries, PSR 1259-63, is a member of a long-period binary system. At least three of the pulsars have ages less than 30,000 yr, bringing the total number of such pulsars to 12. The majority of the new discoveries are distant objects with high dispersion measures, which are difficult to detect at low frequencies. This demonstrates that the survey has reduced the severe selection effects of pulse scattering, high Galactic b…

Rare earth elements and hydrothermal ore formation processes

1992

Abstract The geochemical behaviour of REE is influenced by nearly all important hydrothermal ore formation processes including fluid-rock interactions, fluid precipitations, adsorption and scavenging onto particles, and changes in fluid temperature, pressure, pH, Eh, alkalinity and ligand concentration. Destabilization of REE complexes in response to these physicochemical changes and possible chemical-crystallographic controls determine the concentration and distribution of REE within hydrothermal minerals, mineraloids and amorphous phases. Alteration assemblages of intrusive related mineralisations may exhibit a wide range of REE distributions and REE fractionation trends. The REE distribu…

Environmentalism and Political Participation: Toward a New System of Social Beliefs and Values?

1992

This study examines the social beliefs and values of the Spanish population with regard to environmentalism. A questionnaire on environmental beliefs was produced and administered to two sample groups. The first group, to be called “activists” (comprising 86 subjects), is characterized by belonging to one or other environmental organization. The other, termed “nonactivists” (comprising 410 subjects), is composed of people not belonging to any environmentalist organization. We conclude that, as in other Western countries, environmentalism has moved from being a set of beliefs held by a small group of people to becoming a central element in the system of beliefs characterizing our society. In…

Quantum fluctuations of the conductance in the hopping regime

1992

Abstract The results of the numerical scaling approach for localization are used to discuss the statistical behaviour of the zero-temperature conductance of disordered systems of finite size. In the asymptotic regime of strong localization, where transport is dominated by hopping processes, explicit expressions for the temperature dependence of the fluctuations of the conductance and the resistance are obtained by assuming that the phase coherence length is given by the Mott hopping law. It is shown that the temperature dependence of the fluctuations of the logarithm of the conductance/resistance does not depend on the assumptions concerning the statistics of the hopping processes. The resu…

Solution for an arbitrary number of coupled identical oscillators.

1992

We propose a solution to the problem of solving the Schr\"odinger equation for an arbitrary number of identical one-dimensional harmonically coupled oscillators raised by Fan Hong-yi [Phys. Rev. A 42, 4377 (1990)]. The relationship between the Fock spaces associated with the uncoupled and coupled oscillators is given as well as the coordinate representation of the eigenstates. In view of further applications, the Lie algebraic properties of the model are examined, and the generalization to three spatial dimensions is made.

T-cell cloning in human type I diabetes.

1992

Identification of Insulin in Chick Embryo Retina During Development and Its Inhibitory Effect on DNA Synthesis

1992

Incubation of chick embryo retinal explants with insulin resulted in a pronounced inhibition of thymidine uptake and incorporation into trichloroacetic acid-insoluble fraction. The inhibitory effect was highest with explants from embryos at day 7 and day 8, and thereafter it declined markedly with the age of embryos until day 11. A time-course study of the effect revealed that the inhibition occurred after a lag time; both thymidine uptake and incorporation were not altered significantly after 2-6 h of incubation with insulin, but began to decrease thereafter, reaching the maximum after 16 h. The effect was also dose dependent. After 16 h of incubation, the maximal inhibition (65%) was foun…

The asymmetry in π−3He scattering

1992

Abstract We show that the π + − 3 He asymmetry data obtained in a recent TRIUMF experiment at T π = 100 MeV can be understood in terms of the elementary π N amplitudes. Through a comparison to a full optical-potential calculation that employs realistic Faddeev wave functions for the trinucleon we show that all nuclear-structure dependence cancels for A y at lower energies. At higher pion energies around the Δ-resonance region the sign flip of A y offers the possibility of extracting information about the smaller partial waves.

Collisional models in a nonperturbative approach

1992

Abstract A nonperturbative method set forth recently for handling quantum dynamics in the intermediate regime (far from either the sudden or the adiabatic limit) is applied to soluble two-state collisional models.

Relationship between rat liver microsomal Δ6 and Δ5 desaturase activities and fatty acid composition: comparative effects of coconut and salmon oils …

1992

International audience; The aim of this work was to compare the effects of coconut and salmon oils on rat liver microsomal Δ6 and Δ5 desaturations, during protein restriction. A higher Δ6 desaturase activity was noted in rats fed the low-protein coconut oil diet, in comparison with that occurring in rats fed either a low-protein or normal-protein salmon oil diet. No variation was observed in Δ5 desaturase activity or in 20:4n-6/ 18:2n-6 ratio. The fatty acid composition of liver microsomal phospholipids provided evidence of higher levels of 20:5n-3 and 22:6n-3 in the normal-protein salmon oil group, when compared with the low-protein salmon oil group. No influence of experimental diets on t…

Purification and characterization of a Salmonella typhimurium agglutinin from gut mucus secretions.

1992

One of the earliest events in Salmonella typhimurium pathogenesis seems to be the interaction of the bacterium with the mucus of the gut. After exposing S. typhimurium to guinea-pig colon, we were able to demonstrate by electron microscopy that S. typhimurium bacteria were trapped on, or in, the mucus layer. Specific components isolated from crude mucus secretions were found to aggregate the bacteria. The degree of bacterial aggregation was dependent on the protein concentration of the crude mucus and on time. Aggregation of S. typhimurium could be abolished by sugars: L-fucose exhibited the strongest inhibition, followed by D-glucose, D-galactose and D-mannose. Lectins were also capable of…

Rayleigh scattering of Mössbauer radiation on a myoglobin single crystal

1992

The RSMR technique was used to determine the fraction of radiation which is scattered elastically and inelastically, respectively, into Bragg reflections of a metmyoglobin single crystal. From this measurement 〈x2 1c〉=0.027±0.008 A2 has been determined which is due to long range correlated motions in analogy to acoustic and optic modes in solids.

Volumetric and transport properties of aerosol-OT reversed micelles containing light and heavy water

1992

Densities and viscosities of sodium bis(2-ethylhexyl) sulfosuccinate (AOT in-heptane system containing light and heavy water, as a function of the molar ratio R (R=[H2O or D2O]/[AOT]) were measured at 0, 5, 25 and 40°C. At low R values, the apparent molar volume of deuterium oxide is smaller than that of light water. The difference is related to the strength of the hydrogen bonding H2O and D2O. The viscosities of both H2O-AOT-n-heptane and D2O-AOT-n-heptane systems were explained in terms of intermicellar interactions mainly governed by hydration of the head groups of AOT.

Prophylactic Fluconazole andCandida kruseiInfections

1992

Dire institutionnel et espaces de langage - le cas de l'Algérie - Essai d'une sémio-didactique

1992

This thesis is 1) an discourse analysis of the institution' texts (Algeria, in the eighties) + analysis of the young people in secondary school (part I) ; 2) a semiotic analysis of spaces in Algeria (country, village, secondary school). The results : we showed many contraints in a collective speech, through 2 dominant themas : time, action ; and 2 recessive themas : subject (speaker), mirror. So, education and didactic perspective are useful.

Direct FIA—AS determination of potassium and magnesium in cement samples by use of the slurries approach

1992

A direct procedure has been developed for the flame atomic determination of potassium and magnesium in cement samples. A 50-mg sample is dispersed in 25 ml of 0.13M nitric acid; 100 mul of this slurry is injected in a double channel FIA manifold simultaneously with 100 mul of a 10% (w/v) lanthanum solution. This procedure allows the rapid extraction of potassium and magnesium by leaching of the sample; nitric acid is not necessary if only potassium must be determined and the sample can be diluted with only distilled water. Aqueous standards are used. The manifold employed includes a well-stirred mixing chamber, which provides an adequate on-line dilution of the sample, in order to obtain em…

FIA—FT—IR determination of ibuprofen in pharmaceuticals

1992

A method has been developed for the determination of Ibuprofen (2-[4-isobutylphenyl]-propionic acid) in pharmaceuticals by FT-IR, using the carbonyl band which this compound presents at 1710 cm(-1) in carbon tetrachloride solutions. Samples are dissolved in carbon tetrachloride. In this solvent the excipients are not soluble and so the drug can be directly determined without any additional treatment. The use of a simple FIA manifold permits one to carry out this analysis with a low consumption of reagent and the FT-IR provides a continuous monitoring of the spectral base-line which permits an accurate determination of the maximum in the absorbance band. Also, the FIA system permits easy and…

On the nuclear structure of 229Ra

1992

14 pages, 3 tables, 6 figures.

Lattice quantum hadrodynamics

1992

Quantum corrections to the mean-field equation of state for nuclear matter are estimated in a lattice simulation of quantum hadrodynamics. In contrast with the standard coordinate-space methods used in lattice QCD, the calculations are carried out here in momentum space and on nonhypercubic (irregular) lattices. The quantum corrections to the known mean-field equation of state were found to be considerable.

Obligation de déclaration. Article 50 de la loi, Créances concernées, Prêt dont le remboursement continue après le jugement d'ouverture (non), Soumis…

1992

International audience; (Versailles, 13e ch., 12 nov. 1991, CEPME c/ Soc. Scea Guisset et Guisset Conserves)

Amiable composition. Principes directeurs du procès, Article 9 du NCPC, Application, Pouvoir d'équité, Renversement de la charge de la preuve, Princi…

1992

International audience; (Civ. 2e, 28 févr. 1990, Bull. civ. II, n° 43, p. 24, Société Chantiers modernes)

Amiable composition. Définition, Contrat, Pouvoir modérateur, Eviction de certains droits nés du contrat, Limites, Modification de l'économie du cont…

1992

International audience; (Paris, 19 avr. 1991, Soc. Parfums Stern France, inédit)

Article 40. Champ d'application, Créances nées pendant la période d'observation et demeurées impayées, Résolution du plan et liquidation judiciaire, …

1992

International audience; (Toulouse 18 juin 1990, De Loth, mandataire-liquidateur, c/ Soc. Minoterie Neuf-Clergy)