showing 36 of ~574560 from 574555 documents
Fractal approach in petrology: Small-angle neutron scattering experiments with volcanic rocks.
1988
Following Mandelbrot's pioneering work in 1977, we attempt to use the concept of fractal dimension in petrology. Fractal dimension is an intensive property of matter which offers a quantitative measure of the degree of surface roughness. Neutron scattering experiments have been performed on 18 volcanic rocks from different localities. The scattered intensity as a function of the momentum transfer obeys a power law whose exponent varies, for the rock samples presented, between -3 and -4. We conclude that, at the molecular level, our volcanic rocks are not fractal volumes. With regard to the particle-matrix interface, it is not possible to provide a determination at the present stage of resea…
Quantification of some volatile aromatic compounds of apricot by adding standards
1988
The quantification of twelve volatile aromatic compounds of apricot was realized by adding known amounts of pure compounds directly in the slurry before analysis by vacuum distillation and gas chromatography. This method was compared with the classical technique using an internal standard and was applied to two different apricot cultivars. Large differences were observed between the amounts of volatiles calculated by the two methods. They are due to the differences between the extraction coefficients of the quantified compounds and to the retentions of volatiles on nonvolatile compounds, which may vary according to the polarity.
Value of nude mice xenografts in the expression of cell heterogeneity of human sarcomas of bone and soft tissue.
1988
Summary Nude mice xenotransplants have been performed on human primary sarcomas of bone and soft tissues in order to delve into the cell heterogeneity of these neoplasms. Particular emphasis has been given to the group of small round blue cell sarcomas (Ewing's sarcomas and peripheral neuroectodermal tumors). Out of 31 xenotransplanted sarcomas, 16 cases have grown positively, and many of them continue to be transferred into nude mice on a regular time basis, being presently considered as fully established nude lines. Here we report the results of such a system, which has been followed with optical, electron microscopical, immunohistochemical and cytogenetic techniques. Osteosarcomas make u…
Prediction of Course in Major Depression. Does Psychopathology Predict Future Drug Intake or Relapse?
1988
Pharmacotherapy of panic attacks.
1988
The influence of medication on the course of major depression: a 3-year-follow-up with polydiagnostic measures.
1988
Zur Struktur der Produkte der Reaktion vonE/Z-1-Benzolsulfonyl-3-(1-pentenyl)-indol mit N-Phenylmaleinimid: Ein erster Beitrag zur Konfigurations- un…
1988
The products2,3 of the reaction ofE/Z-1-benzenesulfonyl-3-(1-pentenyl)-indole (1) and N-phenylmaleimide were analysed by1H-NMR spectroscopy. Exemplarily, the structure elucidation of theendo-cyclo-adduct2 b was achieved by using several NMR techniques (diff. NOE-, INDOR-measurements, decoupling experiments, spectra simulation). The1H-NMR-spectroscopically gained prediction of relative configuration and conformation of2 b was supported on X-ray analysis. The cyclohexene ring of the new cycloadducts adopts in the liquid phase and in the crystal a slightly twisted boat conformation.
R plasmids in environmental Vibrio cholerae non-O1 strains.
1988
The occurrence of drug resistance and its plasmid-mediated transferability was investigated in 140 environmental strains of Vibrio cholerae non-O1 and 6 strains of Vibrio cholerae, both O1 and non-O1, of clinical origin. Of the 146 strains tested, 93% were resistant to at least one drug and 74% were resistant to two or more antibiotics. The O1 strains were susceptible to all antibiotics used. A total of 26 of 28 selected resistant wild strains carried R plasmids that were transferable by intraspecific and intergeneric matings. The most common transmissible R factor determined resistance to ampicillin, amoxicillin, and sulfanilamide (30%), followed by resistance to ampicillin and amoxicillin…
Benzodiazepines for catatonic symptoms, stupor, and mutism.
1988
ChemInform Abstract: Preparation of N,O-Aminals as Synthetic Equivalents of H2C=NAr and (H2C=NHAr)+ Ions: Neutral- and Acid-Promoted Transformations.
1988
A general method for the synthesis of N,O-aminals derived from primary aromatic amines is described. The reactivity of these compounds under neutral and acidic conditions has been studied and the title compounds can be envisaged as general purpose H2CNAr or (H2CNHAr)+ equivalents. N,O-Aminals have been converted into perhydrotriazines by moderate heating and into bis(4-aminoaryl)methane derivatives or N-benzylarylamines, respectively when heated in acidic media with pH control. Reduction of N,O-acetals with sodium cyanoborohydride has revealed that the C–O bond is broken exclusively in acidic media.
ChemInform Abstract: Synthesis, Electrochemistry, and Spectroelectrochemistry of (P)Ge(Fc)2 and (P)Ge(C6H5)(Fc): First Example of Metal-Carbon-σ-Bond…
1988
Projections from the medial cortex in the brain of lizards: correlation of anterograde and retrograde transport of horseradish peroxidase with Timm s…
1988
Efferent projections of the medial cortex of the lizards Podarcis hispanica and Gallotia stehlinii were studied by examining the transport of horseradish peroxidase; results were correlated with those from Timm-stained sections. Two efferent systems were found. The first reaches the distal part of the outer plexiform layer in the medial, dorsomedial, and dorsal cortices, i.e., zones that are negative to Timm staining, and possibly originates from horizontal fusiform neurons. The second reaches the Timm-positive zones in the cortex and septum and is topographically arranged: the vertical portion of the intermediate and caudal medial cortex and the entire rostral medial cortex project to the …
Human immunodeficiency virus infection mimics autoimmune hepatitis--a case report.
1988
Improvement of the extraction yield of volatile flavour compounds
1988
National audience
Trabajo feminino y distribucion de rentas en Espana
1988
International audience; En este artículo detallamos la actividad profesional de las mujeres casadas, y medimos, a lo largo del ciclo de vida de los hogares, el impacto del trabajo femenino sobre la distribución de las rentas familiares. A continuación, confrontamos la situación de España con la de otros paises donde han podido efectuarse análisis similares ^Francia, Gran gretaña y Estados Unidos).
Chemie an starren Grenzflächen, 10. Kinetisches Verhalten einiger an „Isothiocyanato-Aerosil” immobilisierter Esterasen – Analogversuche mit Insulin
1988
Amino-Aerosil wird mit Thiophosgen nach Gl. (1) in Isothiocyanato-Aerosil 2 (NCS-Aerosil) ubergefuhrt. Trypsin, Cholinesterase und Acetylcholinesterase werden an 2 nach Gl. (2) immobilisiert. Die Aktivitat der immobilisierten Esterasen wird untersucht auf (a) Lagerstabilitat, (b) Temperaturbestandigkeit und (c) pH-Abhangigkeit. Das kinetische Verhalten der immobilisierten Enzyme wird verglichen mit dem der freien, aber mit n-Butylisothiocyanat behandelten Esterasen. Am Beispiel der Cholinesterase, die uber unterschiedliche Ankergruppen mit Aerosil verknupft wurde, wird der Einflus unterschiedlicher Spacergruppen auf die Hydrolysegeschwindigkeit studiert. Aerosile, die mit Acetylcholin-Analo…
Effect of luminance on photopic visual acuity in the presence of laser speckle
1988
Visual acuity in coherent and incoherent light has been determined by using square-wave gratings of 100% contrast. Luminance was varied from 3 to 400 cd/m2. Coherent illumination resulted in a 40% loss of visual acuity. This is probably due to the masking effect of coherent spatial noise (speckle). However, the most interesting finding is the change in shape of the photopic visual-acuity-luminance function. With coherent illumination, the function is vertically displaced and of a different gradient. An increase in luminance produces a decrease in visual acuity. This indicates that the masking effect of the speckle is dependent on luminance. Two observers were used, and similar results were …
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1988
Monte Carlo simulations are presented for binary (AB) symmetric polymer mixtures (chain lengths NANBN) for the case that an attractive interaction ϵ exists between monomers of the same kind, and the limiting case that one species (B) is very diluted. It is shown that with increasing interaction strength ϵ/(kB · T), T being the absolute temperature, the minority chains collapse to a very dense configuration, while the majority chains stay nearly Gaussian. Both chain radii, structure factors and numbers of nearest neighbour contacts are discussed.
Mass spectra of halogenated esters. 7. Methyl esters of 2-chloro C2C20n-alkanoic acids
1988
The mass spectral fragmentation of a homologous series of methyl esters of 2-chloro n-alkanoic acids ranging from acetic (C2) to eicosanoic (C20) acid on electron impact has been investigated. The fragmentation pathways were elucidated with the aid of the first field-free region metastable ions, the results being presented with one compound, i.e. with ionized methyl 2-chloro-octauoate. Owing to the Cl/H exchanges and to the formation of the non-chlorinated parent esters prior to the fragmentations the spectra show the peak pairs with and without the chlorine atom. The effects become more evident with increasing chain length; shown most visually by the abundance ratios of the McLafferty rear…
Effects of Acifluorfen-methyl on cucumber cotyledons : porphyrin accumulation
1988
Abstract The nitrodiphenyl ether herbicide acifluorfen-methyl and the pyridine derivative LS 82-556 induce porphyrin accumulation in green cucumber cotyledons. When experiments are done with intact plants absorbing the herbicide through the roots, that accumulation is light-dependent. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU) which prevents cellular damages under these conditions (M. Matringe and R. Scalla, Pestic. Biochem. Physiol. 26 , 150 (1986), also inhibits porphyrin accumulation. In contrast, when detached cotyledons are cut into pieces and floated on herbicide solutions, porphyrins accumulate in the dark. Accordingly, DCMU does not inhibit porphyrin accumulation or protect the …
Filming among the Hamar
1988
I've often been asked how I came to take part in Robert Gardner's films in Hamar. What do I think of his film Rivers of Sand and how has working with him influenced the concept of ethnography in my films, Der Sprung uber die Rinder (The Leap Across the Cattle), Der Herr der Ziegen (The Father of the Goats), and Gesang der Hamar Hirten (The Hamar Herdsman and his Music). I've tried to answer these questions and to explain how Jean Rouch and the cinema verite have also influenced me. My films were shot in strict collaboration with the Hamar, determining the choice of themes, collective efforts in the production of the films, and in their analysis.
Effect of gut-derived acetate on glucose turnover in man
1988
1. The effect of acetate absorbed from the gut on glucose turnover has been determined in four healthy subjects during both fasting and an intravenous glucose infusion by using [U-13C]glucose. 2. In the first part of the study, after an overnight fast, a tracer dose of [U-13C]glucose was infused at a constant rate along with an infusion of saline for 7 h. In the second part the saline infusion was replaced by glucose at 4.25 mg min−1 kg−1. In both studies 15 mmol of sodium acetate was given by mouth at 15 min intervals from the fourth to the sixth hour. Glucose turnover, respiratory quotient, metabolic rate and blood levels of acetate, 3-hydroxybutyrate, lactate, insulin, glucagon and gastr…
Hüftgelenkssonographie bei Skelettdysplasien mit metaphysärer Beteiligung
1988
Skeletal dysplasias with metaphyseal involvement show radiological changes which permit their classification. There are, however, changes in the cartilage which could be demonstrated by hip sonography in two children, one with Stickler's syndrome and the other with metaphyseal chondrodysplasia. The dangers of mis-diagnosis are discussed.
Cytosolic epoxide hydrolase in humans: development and tissue distribution.
1988
Cytosolic epoxide hydrolase activity was measured towards trans-stilbene oxide in 41 human adult livers, in 40 fetal livers, in 17 placentas and in fetal and adult lungs, kidneys and gut. The cytosolic epoxide hydrolase activity was measurable in all specimens investigated. The rate of formation of trans-stilbene glycol (pmol/min per mg protein, mean +/- SD) was 55.2 +/- 89.6 (fetal liver). 303.2 +/- 73.2 (adult liver) and 18.8 +/- 13.1 (placenta) In the fetal extrahepatic tissues, the cytosolic epoxide hydrolase activity was 70.0 +/- 9.4 (adrenals), 47.6 +/- 7.2 (gut), 69.4 +/- 22.5 (kidneys) and 43.2 +/- 19.2 (lungs) pmol/min per mg protein, whereas in the adult tissues it was 131.2 +/- 6…
GEOCHEMICAL CONSTRAINTS ON THE ORIGIN OF CALCALKALINE AND ALKALINE MAGMAS OF THE EASTERN TRANS-MEXICAN VOLCANIC BELT
1988
Se presentan datos de elementos mayores, elementos trazas y tierras raras de rocas calco-alcalinas y alcalinas de la parte este del cinturón volcánico transmexicano (TMVB), así como conclusiones acerca de su origen y de su significado tectónico. Las andesitas y dacitas muestran características geoquímicas que descartan su derivación de los magmas basálticos por el proceso de cristalización fraccionada. Las distribuciones gráficas de los elementos LIL y HFS son interpretadas como indicadoras de la formación de magmas en el manto superior modificado por procesos de subducción. Las riolitas se interpretan como resultado de la fusión parcial de la corteza continental.
The source of gibberellins in the parthenocarpic development of ovaries on topped pea plants.
1988
The role and source of gibberellins (GAs) involved in the development of parthenocarpic fruits of Pisum sativum L. has been investigated. Gibberellins applied to the leaf adjacent to an emasculated ovary induced parthenocarpic fruit development on intact plants. The application of gibberellic acid (GA3) had to be done within 1 d of anthesis to be fully effective and the response was concentration-dependent. Gibberellin A1 and GA3 worked equally well and GA20 was less efficient. [(3)H]Gibberellin A1 applied to the leaf accumulated in the ovary and the accumulation was related to the growth response. These experiments show that GA applied to the leaf in high enough concentration is translocat…
A Specific Radioimmunoassay for the Determination of Low Quantities of Indole-3-acetic Acid in Spruce Needles of Healthy and Damaged Trees
1988
Summary The aim of the present investigation was to develop a radioimmunoassay for the quantification of indole-3-acetic acid in needles of Picea abies in damaged and phenotypically healthy trees. Phenols, lipophilic substances or compounds with cross-reactivity had to be separated from the extracts in several purification steps. Measurements were carried out between May and October 1986 on trees from two spruce plantations. Marked differences were found in IAA content in needles of healthy and damaged trees. In most cases the needles of the damaged trees contain lower endogenous IAA levels. The auxin levels also depended on the age of the tree, the year of needle formation, and the vegetat…
UNA RARA CAUSA DI ADDOME ACUTO NELL'INFANZIA. L'Epiploite acuta segmentaria
1988
L'Epiploite acuta segmentaria è fra le cause più rare di addome acuto nell'infanzia. Gli Autori ne riportano tre casi.
Miscellanea. Inorganic Thermochromism. By K. Sone and Y. Fukuda. Springer, Berlin 1987. xi, 134 pp., bound, DM 168.00.—ISBN 3-540-17662-4
1988
Le déroulement de la scolarité au collège : le contexte "fait des différences"
1988
Marie Duru-Bellat, Alain Mingat : Der Ablauf der Schullaufbahn im "Gymnasium" (Collège) : der Kontext "macht die Unterschiede"... Seit dem Colemanbericht beschäftigten sich relativ wenig Arbeiten, besonders in Frankreich, mit der Studie dieser "kontextuellen Auswirkungen", die doch wahrscheinlich "die Unterschiede machten" in Bezug auf die Schullaufbahn der Kinder und soziale Ungleichheiten bewirkten. Konkret sollen hier die Variablen berücksichtigt werden, wie die soziale Zusammensetzung des besuchten Gymnasiums, die Struktur des Lehrkörpers, seine Praxis in Bezug auf die Gruppierung von Schülern, das Platzangebot usw. In diesem Aufsatz befasst sich die Fragestellung zugleich mit methodolo…
Alterable electorates in the context of residential mobility
1988
In some circumstances, politicians set about altering the composition of their electorate with a view to increasing their chances of being re-elected. A hypothesis along these lines is formulated in the context of local elections and residential mobility. Although the hypothesis is general, an assessment of its validity implies auxiliary assumptions related to a specific spatio-temporal context. That is done with reference to conditions prevailing in post-war French metropolitan areas. In the empirical part of the paper, some of the implications are submitted to tests on demographical and political data. On the basis of the tests, and although alternative explanations of the findings are po…
Preparation of electrophoretic variants of Corticosteroid-binding Globulin (CBG) using liquid liquid partition chromatography
1988
Abstract Human corticosteroid-binding globulin (CBG) was purified to homogeneity by application of three different chromatographic methods. After fractionation of pregnancy serum with ammonium sulfate the 80%-pellet was used for affinity chromatography based on tresyl activated Sepharose (Pharmacia, Uppsala, Sweden). The affinity eluate was injected into a Mono Q anion exchange column (Pharmacia). Fractions containing CBG were finally purified by liquid liquid chromatography on LiParGel 750 (Merck, Darmstadt, F.R.G.) 1,2 . The purified protein was characterized by IEF and PAGE. This paper describes a method for the chromatographic separation of the two variants of CBG without a loss of bind…
A simple and general synthesis of symmetrical and unsymmetrical bis(arylamino)methanes. Reactions of N,O‐acetals with nitrogen bases
1988
Bis(arylamino)methanes 4 free of amine contamination have been efficiently synthesized from N,O-acetals 1 following three different methodologies. The first two are useful for symmetrical aminals and involve the decomposition of an N,O-acetal by a base (phenyllithium or a lithium arylamide) and trapping of the resulting methyleneamine 2 by the equimolar amount of the corresponding arylamine. The third method allows the preparation of either symmetrical or unsymmetrical aminals and consists of decomposing the starting N,O-acetal 1 by heating in vacuo in the presence of the desired arylamine. Ein einfacher und allgemeiner Zugang zu symmetrischen und unsymmetrischen Bis(arylamino)methanen. Rea…
Human liver cytosolic epoxide hydrolases.
1988
Human liver epoxide hydrolases were characterized by several criteria and a cytosolic cis-stilbene oxide hydrolase (cEHcso) was purified to apparent homogeneity. Styrene oxide and five phenylmethyloxiranes were tested as substrates for human liver epoxide hydrolases. With microsomes activity was highest with trans-2-methylstyrene oxide, followed by styrene 7, 8-oxide, cis-2-With methylstyrene oxide, cis-1,2-dimethylstyrene oxide, trans-1, 2-dimethylstyrene oxide and 2, 2-dimethylstyrene oxide. With cytosol the same order was obtained for the first three substrates, whereas activity with 2, 2-dimethylstyrene oxide was higher than with cis-1,2-dimethylstyrene oxide and no hydrolysis occurred …
Genetic control of C3 production by the S region of the mouse MHC.
1988
SUMMARY The present paper reports evidence indicating that the level of the third complement component (C3) is regulated by the S region of the murine H-2 complex. In fact, using congenic strains of mice we demonstrate that mice with the k haplotype at the S region show high C3 levels, whereas mice with the d haplotype at the S region show low C3 levels.