showing 36 of ~574560 from 574555 documents
Book Review: Organoselenium Chemistry I. Functional Group Transformations. By A. Krief and L. Hevesi
1989
The Effect of Bialaphos on Ammonium-Assimilation and Photosynthesis II. Effect on Photosynthesis and Photorespiration
1989
Abstract The application of bialaphos (phosphinothricyl-alanyl-alanine) effects a quick photosynthesis inhibition under atmospheric conditions (400 ppm CO2, 21% O2). However, under conditions (1000 ppm CO2, 2% O2) under which photorespiration cannot occur there is no photosynthesis inhibition. In the previous investigation it could be shown that bialaphos splits in plants into phosphinothricin and alanine. The inhibition of glutamine synthetase through freed phosphinothricin results in an NH4 +-accumulation and a decrease in glutamine. With the addition of glutamine, photosynthesis inhibition by bialaphos can be reduced. An NH4 +-accumulation takes place under atmospheric conditions as well…
Light Sensitive Lattice Defects In BaTiO 3 Containing Fe
1989
Electron spin resonance spectra, which can consistently be explained by the models Fe4+ - Vo and Fe5+ - vBa, have been observed with BaTiO3 containing Fe. Also Fe3+ and - Fe3+ - Vo have been identified. All these centers as well as several unidentified ones are observed to change their charge states under illumination. They thus are possibly in involved in photorefractive processes in BaTiO3 containing Fe.
Sedimentation properties of chitosomal chitin synthetase from the wild-type strain and the 'slime' variant of Neurospora crassa.
1989
Marked differences in the pattern of sedimentation of cellular structures were observed after isopycnic centrifugation of crude cell-free preparations from the Neurospora crassa wall-less 'slime' variant and mycelial wild-type strain. Kinetic studies of particle sedimentation showed that the various types of subcellular components, as revealed by turbidity, UV absorption, polypeptide patterns, and chitin synthetase activity determinations, sediment independently of one another. An important feature was the finding that chitin synthetase from 'slime' peaked at a median specific gravity of 1.1201 +/- 0.0036, whereas that from wild-type strain sedimented at a higher buoyant density (specific g…
Synthese vonN-Glycopeptid-Partialstrukturen der Verknüpfungsregion sowohl der Transmembran-Neuraminidase eines Influenza-Virus als auch des Faktors B…
1989
Mit Hilfe der Schutzgruppenkombination Boc-Gruppe/Allylester und Acetylschutz im Kohlenhydratteil wurden die geschutzten N-Chitobiosyl-asparagin-peptide 12a und 14 synthetisiert, die der Verknupfungsregion des Faktors B des menschlichen Komplementsystems und einer Influenza-Virus-Neuraminidase entsprechen. Aus dem vollgeschutzten Glycopeptid 12a liesen sich der Allylester und die Acetylschutzgruppen simultan mit methanolischem Ammoniak und die Boc-Schutzgruppe mit wasserfreier Trifluoressigsaure ohne storende Nebenreaktionen entfernen. Versuche, die Boc-Gruppe aus an den Kohlenhydrat-Hydroxyfunktionen deblockierten Glycopeptiden abzulosen, fuhrten uberwiegend zur Spaltung der O-glycosidisch…
Properties of the microsomal and cytosolic glutathione transferases involved in hexachloro-1:3-butadiene conjugation
1989
Hexachloro-1,3-butadiene (HCBD) is a substrate for the hepatic microsomal glutathione transferases and is metabolised at higher rates by these enzymes than their cytosolic counterparts. Conjugation reactions catalysed by the microsomal and cytosolic transferases have been studied and characterized using this substrate and 1-chloro-2,4-dinitrobenzene (CDNB). In rat liver microsomes the Km values for HCBD and CDNB were 0.91 and 0.012 mM and in cytosol 0.51 and 0.10 mM respectively. Vmax values for HCBD were 1.39 and 0.35 nmol conjugate formed/min/mg protein for microsomes and cytosol respectively. In microsomal systems HCBD was a potent competitive inhibitor of the metabolism of CDNB with a K…
ChemInform Abstract: A Series of Calix(4)arenes, Having Two Opposite Para Positions Connected by an Aliphatic Chain.
1989
LOW-DOSE INTERLEUKIN-2 INDUCES SYSTEMIC IMMUNE RESPONSES AGAINST HBsAg IN IMMUNODEFICIENT NON-RESPONDERS TO HEPATITIS B VACCINATION
1989
Abstract A metabolic monocyte defect appears to correlate with non-responsiveness to hepatitis B vaccine in many patients on haemodialysis. This defect prevents production of interleukin-2 during T-cell activation after antigen contact. Receptors for interleukin-2 are, however, expressed in greater numbers than in healthy subjects or uraemic responders to hepatitis B vaccination. In this study, ten uraemic patients, previous non-responders to vaccination against hepatitis B, were revaccinated with the same vaccine combined with one intramuscular injection (2·5 × 10 5 U) of natural human interleukin-2. Systemic production of antibodies against hepatitis B surface antigen was initiated in tho…
ChemInform Abstract: Carbohydrates as Chiral Templates: Asymmetric Ugi-Synthesis of α-Amino Acids Using Galactosylamines as the Chiral Matrices.
1989
Bibracte, Mont-Beuvray (Nièvre)
1989
National audience
El rectorado de la Universidad de Valencia durante el siglo XVI
1989
La conservación de los recursos vivos marinos antárticos en la Convención de Canberra de 1980
1989
l. INTRODUCCIÓN.- II. LA CONSERVACIÓN DE LOS RECURSOS MARINOS VIVOS EN LA ANTÁRTIDA.- III. VENTAJAS DE ESTE PLANTEAMIENTO CONSERVACIONISTA.- IV. INCONVENIENTES A LOS CONSERVACIÓN DE LOS RECURSOS VIVOS MARINOS ANTÁRTICOS: 1. Los recursos marinos vivos protegidos; 2. Soberanía y jurisdicción en la Antártida; 3. Necesidad de información científica; 4. Procedimiento de adopción de las medidas de conservación; 5. Las medidas de conservación; 6. El control de la aplicación de estas medidas; 7. El relativismo de los tratados; 8. Daños al medio ambiente antártico por otras actividades.- V. CONCLUSIONES.
Dopplersonographische Blutflußmessung der A. umbilicalis: Ist ein Screening sinnvoll?
1989
251 Einlingsgraviditaten mit gesichertem Gestationsalter wurden zwischen der 28. und 42. Woche p.m. dopplersonographisch untersucht. Die Flusmuster der Nabelarterien wurden durch Bestimmung der A/B-Ratio nach Stuart anhand einer eigenen Normkurve ausgewertet. Als pathologisch wurden Werte oberhalb der gestationsalterbezogenen 95. Percentile angenommen. Die Messungen wurden mit einem gepulsten Dopplersonographiegerat der FA SMS durchschnittlich 2 Wochen antepartal durchgefuhrt.
Inclusive pion-nucleus double charge exchange.
1989
Inclusive double charge exchange reaction is studied by using a model which combines a microscopic many-body calculation of reaction probabilities with a Monte Carlo simulation procedure. Comparison with present experimental results requires that the (\ensuremath{\pi},2\ensuremath{\pi}) reaction be included and a proper evaluation of this latter reaction is also done. The combined results compare favorably with experiment, giving extra support to this model of the pion-nucleus interaction which was previously shown to provide a good description of all other inclusive reactions and elastic scattering.
Совершенствование управления в условиях интенсификации производства
1989
В сборнике рассматриваются методические вопросы совершенствования управления и планирования народного хозяйства союзной республики и отдельных его структурных подразделений. Авторы предлагают применять экономические методы хозяйствования, математические модели и ЭВМ.
Les épîtres dédicatoires et les secrétaires du roi (1515-1547) ou le portrait de l'honnête homme au siècle de la Renaissance
1989
International audience
V I G — A Visual and Dynamic Decision Support System for Multiple Objective Linear Programming
1989
In this paper we describe the principles of VIG (Visual Interactive Goal Programming), a Multiple Criteria Decision Support System, recently developed by Korhonen. PARETO RACE is a corner-stone of this system, which is designed to support both the modelling and solving of a multiple objective linear programming problem. The interface is based on one main menu, spreadsheets, and interactive use of computer graphics. VIG provides the decision-maker with the possibility to approach his/her decision problem by using an “evolutionary approach”. This means that the decision-maker does not have to specify the model precisely prior to solving the problem. In fact, the model evolves progressively. W…
Neue technische Entwicklungen
1989
Vom 1. 9. 1985 bis zum 31. 12. 1988 wurden 87 Anastomosen gefertigt; 59 wegen Sigmadivertikultitis, 21 bei Morbus Crohn/Colitis ulcerosa, 4 nach Radiatio und 3 nach ischamischer Kolitis. 47 manuelle Anastomosen, vorwiegend im rektosigmoidalen Ubergang stehen 40 Stapleranastomosen, besonders im oberen und mittleren Rektumdrittel gegenuber. Nach Klammernaht setzte die Stuhltatigkeit fruher ein, die Infusionsdauer war kurzer. Ein symptomatischer Nahtbruch entstand nach Anwendung des EEA-Premiumgerates. Kein Patient verstarb. Narbige Anastomosenstenosen entwickelten sich nicht. Besonders im oberen und mittleren Rektum stellen die Stapler eine wichtige Erganzung der chirurgischen Technik dar.
On the enhancement of stereoselection by cooperation between chiral auxiliaries. Asymmetric diels-alder reactions with fumaric acid bis ((S)-proline …
1989
Abstract Fumaric acid bis ((S)-proline benzyl ester) amide reacts with cyclopentadiene in thermal and Lewis acid catalyzed Diels-Alder reactions to give the cycloadducts with high yields and diastereomeric ratios up to 100:1.
Momento y responsabilidades españolas en la construcción europea
1989
Polymers with Side-chain Mesogenic Units
1989
Liquid crystalline (LC) polymers are usually prepared by combining formanisotropic structural units (so-called mesogenic groups) and polymer chains (Figure 1). The mesogenic groups used for this purpose are rigid rod-like or disc-like units, which are known to favour LC phases in the case of low molar mass substances. There are two main ways of combining the mesogenic groups and polymer chains. The mesogenic groups can either be incorporated actually into the polymer chains (LC main-chain polymers, see Volume 5, Chapter 38) or they can be attached to flexible polymer chains as side groups (LC side-chain polymers).
Toxisch bedingte Myopathien
1989
Sammelbezeichnung fur Arzneimittel-bedingte Myopathien mit vornehmlich subakuter und akuter Verlaufsform, wobei es bis zur Rhabdomyolyse kommen kann. Besserung oder vollstandige Ruckbildung nach Absetzen der Medikation. Der zeitliche Zusammenhang (24 Stunden bis zu Monaten) und die Dosisabhangigkeit sind unterschiedlich. Klinisch finden sich sowohl schmerzhafte als auch schmerzlose Verlaufsformen, sowie Ubergange zu Myalgien, Muskelkrampf-Syndromen bzw. chronisch-atrophierenden Verlaufsformen. Lokalisation vorwiegend proximal an der Stammuskulatur; besonders beim akuten Syndrom kann es zu generalisierten Formen mit haufig kardialer Beteiligung kommen. Reflexe meist auslosbar. Klinisch finde…
Etude de la germination des graines de Solanum elaeagnifolium Cav., adventice du Tadla (Maroc)
1989
National audience
Metode cientific i didactica de les ciencies socials
1989
E. Mira i López en la Psicología Internacional
1989
El objetivo del presente trabajo es determinar el impacto actual de un autor español, Emilio Mira i López, en la comunidad psicológica internacional, a través del método del análisis de las citas recibidas en un periodo de 22 años en el Social Sciences Citation Index. Es el único psicólogo español considerado como eminente por su contribución en el ámbito psicológico, formando parte de lo que Marañón llamó la 'generación de la preguerra', que rompió en España con viejos moldes y tradiciones, abriéndose a las clínicas extranjeras (alemanas y francesas), habituándose a la lectura de revistas científicas que iban penetrando poco a poco, e intentando una reforma a fondo de la organización, la e…
Le mouvement ouvrier et le socialisme en Finlande 1884-1918
1989
Traduction dans "Matériaux pour l'histoire de notre temps", n° 9, juillet-septembre 1989, pp. 18-26 (du finnois en français)
Quiste Oseo Aneurismático Sólido
1989
One case of solid aneurysmal bone cyst is reported. It's an un usual intraoseus lesion wich can be mistaken with a variety of other conditions more aggressive. The clinical, pathologic and inmunohistochemical features are more suggestive of a benign lesion with a typical charaderistics.
Homéomorphies et canalisations évolutives: Le rôle de l'ontogenèse.Quelques exemples pris chez les Ammonites du Jurassique
1989
Resume La signification paleobiologique des homeomorphies et des processus evolutifs homologues qui les ont induits, sont analyses a partir de 7 exemples choisis parmi les ammonites du Jurassique. Les formes etudiees sont soit largement repandues soit endemiques dans les mers de plates-formes de l'Europe moyenne ou regnaient au cours du Jurassique des conditions ecologiques bien differentes de celles des regions mediterraneennes-plus oceaniques-ou vecurent la plupart des ancetres de ces formes. Il est montre que les tendances evolutives repetitives observees peuvent souvent etre comprises comme les resultats de strategies evolutives impliquant, au sein de chaque groupe analyse, l'adoption p…
Identification of Point Mutations in Genes Coding for tum-Antigens. A Step Towards the Understanding of Mouse and Human Tumor-Specific Transplantatio…
1989
Most experimental tumors induced with chemical carcinogens or UV radiation express individually specific transplantation antigens that elicit a T cell-mediated immune rejection in the syngeneic animals (Prehn and Main 1957; Klein et al. 1960; Kripke 1981; Uyttenhove et al. 1983). The characterization of these transplantation antigens has proved very difficult and several different approaches have been followed. One involves the search for specific antibodies to isolate the antigen by immunoprecipitation. Unfortunately, tumors seldom elicit antibodies directed against their specific transplantation antigens. One notable exception is UV-induced tumor 1591, and the molecules that were isolated…
Das Sigma-Conduit, eine überlegene Alternative zum Ileum-Conduit?
1989
Unter den inkontinenten Harnableitungen liegt der Hauptvorteil des Colon-Conduit im Refluxschutz [1, 2, 4, 6]. Bei der Verlaufsanalyse unserer eigenen Patienten mit Colon-Conduit wurde spezielles Augenmerk auf Technik und Komplikationen der Harnleiterimplantation gelegt.
Resultados de la Técnica de Bristow-Helfet en el tratamiento de la luxación recidivante del hombro
1989
En este artículo se hace una revisión de los resultados de los diecisiete ( 17) casos de Luxaciones Recidivantes de Hombro que los autores han tratado en su Servicio siguiendo la técnica de BRISTOW-HELFET. Se trata de una técnica de sencilla ejecución y los resultados anatómicos y funcionales son, habitualmente, satisfactorios, utilizando la técnica de Evaluación dle ROWE y ZARINS.
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1989
Computerized brain tomography measures compared with spontaneous and suppressed plasma cortisol levels in major depression.
1989
We determined brain density and ventricular measurements with computerized tomography (CT) in 33 depressed patients and compared the results with basal plasma cortisol and its suppressibility by dexamethasone. Mean plasma cortisol was positively related to elevated ventricular brain ratio (VBR). No association could be found between dexamethasone suppression test (DST) status and VBR or any other CT parameter. Elevated plasma cortisol levels and increased VBRs were positively correlated with total scores on the Brief Psychiatric Rating Scale, the Global Assessment Scale and the Bech-Rafaelsen Melancholia Scale, but they were not significantly correlated with total score on the Hamilton Anxi…
Proton-Rich Light Nuclei
1989
A basic question for a given element of how few or how many neutrons can be contained in its nucleus and still result in a “bound” system, and the resulting consequences on our present concept of nuclear structure, have been the focus of much recent research on highly unstable nuclei. It is only during the last several years that the limit of nuclear stability has been reached in a few areas of the nuclear chart. Except among the lightest elements, knowledge of the limit on the neutron-excess side is still beyond our experimental capability. For the heavier elements, the gap between the most neutron-rich isotope known and the isotope which is predicted to define the neutron drip-line more o…
Ontogenetic variations of some enzymes indicentrarchus labrax(Serranidae)
1989
Abstract The ontogenesis of isozyme patterns of alcohol dehydrogenase (ADH), glycerol‐3‐phosphate dehydrogenase (α‐GPDH), lactate dehydrogenase (LDH), malate dehydrogenase (MDH), glucose‐6‐phosphate dehydrogenase (G‐6‐PD) and glucosephosphate isomer‐ase (GPI) in Dicentrarchus labrax was studied. ADH is active only in the liver of the adult; a‐GPDH is active in only two tissues in the adult: the A2 isozyme in white skeletal muscle and the B2 isozyme in the liver. Differential gene expression was found only for LDH, MDH and GPI, which have polymeric structure. The LDH, MDH and GPI isozymes 30 days after hatching were completely active and showed patterns very similar to those of the adult. Sp…
Photoreactivity of Iron-Doped Titanium Dioxide Powders for Dinitrogen Reduction to Ammonia
1989
The production of NH3 from N2 and H2O on Fe/TiO2 has been studied in a continuous photoreactor under UV radiation. An ESR study of the catalysts shows that Fe3+ ions are better electron traps than Ti4+ ions. This trapping can be irreversible if the corresponding holes originate stable species adsorbed on the catalyst surface. The charge separation, thus favoured by the Fe3+ ions, helps the N2 adsorption by its reaction with surface species activated by holes. The best activity is found when no excess Fe is segregated at the surface; overall turnover for N2 reduction as high as 6 e−/Fe atom can be reached before catalyst deactivation.