showing 36 of ~574560 from 574555 documents
LE NEOPLASIE CISTICHE BENIGNE DEL TESTICOLO IN ETA' PEDIATRICA: revisione della letteratura, contributo clinico personale e nuove proposte terapeutic…
1990
Gli Autori ribadiscono l'importanza dell'approccio multisciplinare alle masse del testicolo e sottolineano il corretto atteggiamento terapeutico, sulla base della revisione della letteratura e dopo valutazione dei dati di una casistica nazionale
Molecular analysis of a human liver mitochondrial ornithine transcarbamylase deficiency.
1990
The liver of a young girl which had been successfully transplanted was investigated at the ornithine transcarbamylase (OTC, EC 2.1.3.3) gene expression level. Northern blot hybridization using a human OTC cDNA probe showed a greater than 80% decrease in specific OTC mRNA although having the same molecular size as a normal control. OTC polypeptide was simultaneously synthesized with a normal molecular size but at a low level (20%) as shown by immunoblotting. The OTC enzyme from the deficient liver exhibited very little catalytic activity (7.2% as compared to the normal subject). These results may support several explanations of this disease such as mutation of the OTC gene promoter leading t…
Créancier de l'article 40. Droit de poursuite individuelle
1990
International audience
Matter, quantum gravity, and adiabatic phase
1990
Based on the observation that particle masses are much smaller than the Planck mass, a framework for the matter-gravity system in which matter follows gravitation adiabatically is examined in a path-integral approach. It is found that the equations that the resulting gravitational wave function satisfies involve, in addition to the expectation value of the matter stress tensor, an adiabatically induced gauge field which can lead to interesting topological structures in superspace. Such a non-trivial geometric contribution modifies the semiclassical quantization condition and can change the conserved quantities associated with the symmetries of the system. © 1990 The American Physical Societ…
Suspension des poursuites individuelles tendant à la résolution d'un contrat pour défaut de paiement d'une somme d'argent. Bail commercial. Clause ré…
1990
International audience
Suspension des poursuites individuelles. Contrats en cours. Bail commercial. Résiliation. Application des textes relatifs à la période d'observation.…
1990
International audience
ChemInform Abstract: Reactions of Pyrano(3,4-b)indol-3-ones with Dienophiles: Consecutive (4 + 2) Cycloaddition/Cycloreversion/1,2 Elimination.
1990
Methylpyrano[3,4-b]indol-3-ones 1 react with selected dienophiles (as acetylene equivalents) in a consecutive Diels-Alder/cycloreversion/1,2 elimination reaction sequence to furnish the 1-methyl- and 1,4-dimethylcarbazoles 4.
The effects of phorbol esters on choline phospholipid hydrolysis in heart and brain
1990
The efflux of choline was determined in rat striatal slices, incubated chicken atria and perfused chicken hearts. 4 beta-Phorbol-12 beta,13 alpha-dibutyrate (PDB) and 4 beta-phorbol-12 beta-myristate, 13 alpha-acetate (PMA) were used to stimulate protein kinase C. The other phorbol esters, 4 beta-phorbol-13 alpha-acetate (PAc) and 4 alpha-phorbol-12 beta,13 alpha-didecanoate (4 alpha PDD), known to be inactive, were tested to evaluate the specificity of the responses. PDB markedly enhanced the efflux of choline in all of the three preparations. The PDB-evoked efflux of choline in incubated chicken atria was equal to the net production of choline and, therefore, was not caused by translocati…
ChemInform Abstract: Carbohydrates as Chiral Templates: Diastereoselective Ugi Synthesis of (S)-Amino Acids Using O-Acylated D-Arabinopyranosylamine …
1990
Abstract Enantiomerically pure (S)-amino acids are synthesized via a highly diastereoselective Ugi reaction using 2,3,4-tri-O-pivaloyl-α-D-arabinopyranosylamine as the chiral template.
New acetylenes fromChrysanthemum coronarium L.
1990
The investigation of the aerial parts of Chrysanthemum coronarium yielded, in addition to several known compounds, two new acetylenic sulfoxides 9 and 10, and a new thiophene spiroacetal enol ether 11. Their structures were deduced by spectroscopic and chemical methods.
ON THE STABILITY OF SUPERSYMMETRY IN CURVED SPACE-TIME
1990
We discuss the stability of the classical supergravity background in a simple supersymmetric model at the quantum level, showing that two different pictures emerge depending on whether the emphasis is placed on the conformal invariance or on the supersymmetry invariance of the theory.
Differential effect of insulin and epidermal growth factor on the mRNA translocation system and transport of specific poly(A+) mRNA and poly(A-) mRNA…
1990
The efficiency of efflux of rapidly labeled poly(A)-containing mRNA from isolated rat liver nuclei was found to be modulated by insulin and epidermal growth factor (EGF) in a biphasic but opposite way. At physiological concentrations (10 pM insulin and 1 pM EGF), maximal stimulation of the transport rate by insulin (to 137%) and maximal inhibition by EGF (to 69%) were obtained; at higher concentrations (greater than 100 pM and greater than 10 pM, respectively), the amount of poly(A)-containing mRNA released into the postnuclear supernatant was nearly identical with the level found in untreated nuclei (= 100%). Using mRNA entrapped into closed nuclear envelope (NE) vesicles as a model system…
Melatonin modulates diacylglycerol and arachidonic acid metabolism in the anterior pituitary of immature rats.
1990
In pituitary glands of immature rats prelabeled in vitro with [3H]arachidonic acid, melatonin diminished the luteinizing hormone-releasing hormone (LHRH)-induced increase in [3H]diacylglycerol accumulation as well as [3H]arachidonic acid release from the tissue. Melatonin reduced also LHRH-stimulated incorporation of [3H]glycerol into pituitary [3H]diacylglycerol. The effect was day-time dependent: in the evening experiment melatonin was effective at 0.1 nM concentration while in the morning it had no effect even at 10 nM concentration. The effect of melatonin was also abolished by pretreatment with pertussis toxin. Diacylglycerol and/or arachidonic acid might serve as 2nd messengers transd…
A possible role for cyclic guanosine monophosphate in the rat pineal gland.
1990
Abstract Adrenergic stimulation of pinealocytes induces an increase of both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). However, for cGMP no biological effects have been demonstrated so far. Therefore we tested the effects of the analog 8-bromo-cGMP on synaptic ribbon numbers and on melatonin synthesis as reflected by N -acetyltransferase (NAT) activity in the rat pineal gland in vitro. Incubation for 6 h with 8-bromo-cGMP did not change the activity of serotonin NAT but in increased the number of synaptic ribbons. These results indicate that cGMP is involved as a second messenger in the regulation of synaptic ribbon numbers in the rat pineal gland.
Significance of the remotely sensed thermal infrared measurements obtained over a citrus orchard
1990
Abstract In this work we have developed a theoretical model that helps the interpretation of the remotely sensed thermal infrared measurements carried out over citrus orchards. A detailed analysis of the different factors which take part in the definition of the effective emissivity and temperature (observation height, viewing angle, type of soil, dimensions and separation between orange trees) is made. The model was validated under vertical observation in a citrus orchard during seven nights. In this situation we have determined that the model performs to an accuracy of about 1%.
false
1990
This lecture summarizes some recent results and ideas about interrelations between degradation and mechanical behaviour of polyolefins. Aspects of the heterogeneous nature of oxidative degradation in the solid state, the feedback mechanism in degradation, effects of morphology, particularly orientation, on the degradation process, and the influence of degradation on plasticity and on the ultimate mechanical behaviour are discussed.
Measurement of residual stresses by the hole-drilling method: General stress-strain relationship and its solution
1990
A measurement of the phases of the CP-violating amplitudes in K0→2π decays and a test of CPT invariance
1990
Abstract The phases of the CP-violating amplitudes in K0→π+π− and K0→2π0 decays, φ+−=46.9°±2.2° and φ00=47.1°±2.8°, have been measured in the same experiment, and a direct comparison gives the phase difference φ00−φ+−=0.2°±2.9°. This result leads to an upper limit on possible CPT violation in the K0 mass matrix, of |(m K 0 −m K 0 )/m K 0 | −18 at the 95% confidence level and is the most stringent test of the equality of particle and antiparticle masses.
Effects of peroxidizing herbicides on protoporphyrin IX levels in non-chlorophyllous soybean cell culture
1990
Abstract The mode of action of 16 peroxidizing herbicides belonging to four different families (diphenyl ethers, oxadiazon, pyridine derivatives, and pyrazole derivatives) has been studied in nonchlorophyllous soybean cell cultures. Whenever possible, we have compared active and inactive compounds. Phytotoxic effects were estimated on the basis of growth inhibition, either in the dark or in the light. Protoporphyrin IX accumulations were estimated in dark-treated samples, using a simple methodology. In all cases, we have found a positive correlation between cellular damages and protoporphyrin IX accumulations. The results provide further evidences in favor of the light-dependent activity of…
Boundedness and spectral invariance for standard pseudodifferential operators on anisotropically weighted LP-Sobolev spaces
1990
It is shown that pseudodifferential operators with symbols in the standard classes S ρ,δ m (ℝn) define bounded maps between large classes of weighted LP-Sobolev spaces where the growth of the weight does not have to be isotropic. Moreover, the spectrum is independent of the choice of the space.
The catalytic-thermometric determination of molybdenum in steels based on the hydrogen peroxide-iodide indicator reaction
1990
Abstract The Mo VI -catalysed hydrogen peroxide-iodide reaction has been optimised for thermometry in an HCl medium using the initial slope method. The substitution of sodium perborate by H 2 O 2 and the conversion of the reaction to a process showing a Landolt effect are considered and discussed. The linear range extended from 0.2 μg Mo VI ml −1 to 1.2 μg Mo VI ml −1 with a detection limit of 0.06 μg Mo VI ml −1 . Interferences were also studied. The optimised procedure was applied to the evaluation of molybdenum in steels after extraction with α-benzoinoxime in chloroform.
Ellipsometric study of the physical states of phosphatidylcholines at the air-water interface
1990
Etude des couches monomoleculaires de dimyristoylphosphatidylcholine, de dipalmitoylphosphatidylcholine, de distearoyl phosphatidylcholine, de diarachidoylphosphatidylcholine a l'interface air/eau
C7(P32) and C6(P34) PR proteins induced in tomato leaves by citrus exocortis viroid infection are chitinases
1990
[EN] Two chitinases induced in tomato leaves (Lycopersicon esculentum Mill cv. Rutgers) by citrus exocortis viroid (CEV) infection were purified. Their molecular masses determined by sodium dodecyl sulfate-gel electrophoresis were 32 kDa and 34 kDa and by filtration through Sephadex G-100 were 23 kDa and 25 kDa, respectively. These chitinases (P32 and P34) have been shown to be identical to the tomato pathogenesis-related proteins C7 and C6. They were purified in three stages: ammonium sulphate fractionation, chitin affinity chromatography and CM-Sepharose chromatography. The characterization of P32, the major component of the CEV-induced chitinase activity, revealed a basic protein (pI, 8·…
Search for neutral Higgs bosons from supersymmetry in Z decays
1990
The light scalar Higgs boson h and the pseudoscalar Higgs boson A of the minimal supersymmetric standard model have been searched for in the processes e+e−→hff and e+e−→hA using data collected by ALEPH at the LEP e+e− collider, with center of mass energies at and near the Z peak. Using a variety of signatures adapted to various mass ranges for h and A, we have excluded a large domain in the parameter space. For large values of ν2ν1, the ratio of the vacuum expectation values of the two Higgs fields, the whole range from 0 to 38.8 GeV is excluded for Mh and MA at 95% CL.
Groupe de travail sur l'analyse régionale de la relation formation-emploi : problématiques et méthodes
1990
International audience; Depuis une vingtaine d'années, et plus encore depuis la mise en place de la décentralisation, des systèmes d'aide à la décision sont demandés par les décideurs régionaux et locaux en matière de formation initiale et continue. Pour tirer les leçons des expériences passées et formuler des propositions pour le développement des observatoires régionaux de l'emploi et de la formation, prévus dans le cadre des contrats de Plan Etat - Région, le C.E.R.E.Q. a pris l'initiative de réunir un groupe de travail, dont les premières réflexions sont relatées ici. Il insiste particulièrement sur la prise en compte de l'évolution socio-économique des comportements et des stratégies d…
Developmental Changes and Daily Rhythm in Melatonin-Induced Inhibition of 3′,5′-Cyclic AMP Accumulation in the Rat Pituitary
1990
Melatonin's transduction mechanisms were investigated using in vitro cultured anterior hemipituitaries. Melatonin inhibited cAMP and 3',5'-cyclic GMP accumulation in neonatal rat anterior pituitary stimulated with LHRH. Maximal inhibitory effect was reached within 25 min and persisted for at least 20 min. Inhibition of cAMP accumulation is specific for melatonin because its analogs N-acetylserotonin and 5-methoxytryptamine are 1000 times less potent. Melatonin effect is age- and time-dependent. Marked inhibition was observed in 5-, 10-, and 14-day-old rats but not in 29-day-old ones. Melatonin was significantly more potent when applied at the end of the light period as compared with the fir…
Adhesion, growth and cytoskeletal characteristics of 8701-BC breast carcinoma cells cultured in the presence of type V collagen
1990
Type V collagen is one of the minor components of the extracellular matrix (ECM) whose content is increased in cases of ductal infiltrating carcinomas of the breast. In order to clarify its biological role, we have investigated the effect of this molecule, both as substrate and as soluble factor, on the behaviour of a breast carcinoma cell line (8701-BC) grown in vitro. Cell-collagen adhesion was monitored for 24 h from plating in the absence or presence of serum. The influence of type V collagen on cell growth was followed during 9 days of culture, and the actin-vinculin arrangement was studied by simultaneous fluorescent immuno-staining. The results indicate that type V collagen is not a …
Nullstellen bei Lösungen der Differentialgleichung y(n) + gy(n−1)+ fy = 0
1990
Phospholipid-based reverse micelles.
1990
Physicochemical investigations on the aggregation of phospholipids (mainly phosphatidylcholines) in organic solvents are reviewed and compared with the aggregation behaviour of phospholipids in aqueous medium. In particular we review the data showing that phosphatidylcholines (lecithins) form reverse micellar structures in certain apolar solvents. In these systems not only low molecular weight compounds but also catalytically active enzymes and entire cells can be solubilized. In addition, highly viscous phosphatidylcholine gels can be obtained in organic solvents upon solubilizing a critical amount of water. Generally, phospholipid-based reverse micelles can be regarded as thermodynamicall…
Symmetric-group approach to the study of the traces ofp-order reduced-density operators and of products of these operators
1990
In this work we give the values of traces of p-order reduced-density operators. These traces are obtained by application of the spin functions and of the symmetric-group properties. The relations obtained here will allow an easy and fast evaluation of the high-order spin-adapted reduced Hamiltonian matrix elements and high-order Hamiltonian moments.
Radiative muon capture and the value of gP in nuclei
1990
Abstract Radiative muon capture by nuclei is analyzed by means of sum rule techniques, providing a total photon yield calculated with RPA precision. The measured yields relative to the ordinary muon capture rate are well reproduced for the nuclei 12C, 16O and 40Ca using a value of the pseudoscalar weak coupling constant gP enhanced by only 25% with respect to its canonical value. Therefore, the large renormalization of gP claimed up to now must be reconsidered.
Untersuchung über den Zusammenhang zwischen verschiedenen Indikatoren des Wachstumstyps
1990
In der vorliegenden Untersuchung werden elf Variable aus dem Fernrontgenseitenbild, die als Indikatoren des “Wachstumstyps” gelten oder damit in Beziehung stehen konnen, gemessen und zusammen mit einem errechneten Kombinationsmas miteinander korreliert. Die Zusammenhange werden interpretiert und die Mase mit dem Begriff “Wachstumstyp” in Beziehung gesetzt.
Real-time microfluorescence studies of Langmuir-Blodgett deposition: Monolayer adsorption and desorption
1990
Abstract Observations of the meniscus region in a typical Langmuir-Blodgett configuration are obtained using fluorescence microscopy. Studies of the meniscus position as a function of pH demonstrate that the meniscus height increases upon charging the monolayer owing to the repulsive interaction between monolayer and substrate surfaces. Through the correspondence between meniscus height and contact angle the adhesion forces between monolayer and substrate as a function of monolayer charge are assessed. The phenomenon of desorption upon resubmerging a deposited film is described and it is shown that the meniscus height at the onset of the desorption is greater for higher pH.
Isolation, identification and toxicological characterization of TSS 1, a new mycotoxin of the rosenane class.
1990
11-β-hydroxy-7-deoxy-rosenonolactone (TSS1), a product of the pathogenic fungusTrichothecium roseum (Moniliaceae) was isolated from culture medium extracts and completely described in its structure by spectroscopical methods.TSS 1 was classified as a representative of the lactone series of the rosenane class and as a structural isomer to Rosenololactone (1) and Rosololactone (2, 3).TSS1 showed toxic effects in the growth inhibition test toE coli (EC 50: lOμg/mL) andB subtil is (EC 50: 17μg/mL), inhibited fermentation of yeast (EC 50: 2.8μg/mL) and suppressed motility ofAnemia satina larvae (EC 50: 45/μg/mL).Rosenonolactone, the best known representative of that mycotoxin class, showed only …
Sur les fibrations de Milnor de familles d'hypersurfaces � lieu singulier de dimension un
1990
Cytoskeletal Heterogeneity of an Epithelioid Sarcoma with Expression of Vimentin, Cytokeratins, and Neurofilaments
1990
We studied an unusual sarcoma with morphologic features diagnostic of epithelioid sarcoma by conventional light microscopy, transmission electron microscopy, and immunohistochemistry. The primary tumor, which was located in the deep soft tissues of the buttock of a 32-year-old woman, and its metastases to lymph nodes, liver, and lung were available for investigation. The histomorphological and ultrastructural appearance of the primary tumor and its metastatic deposits were typical of epithelioid sarcoma. Immunohistochemistry revealed a strong and uniform reactivity for vimentin in both the primary tumor and its metastases. In contrast, a marked cytoskeletal heterogeneity became evident for …