showing 36 of ~574560 from 574555 documents

Gastos y costes de la ensenanza

1991

International audience

Gastos[SHS.EDU]Humanities and Social Sciences/Education[SHS.EDU] Humanities and Social Sciences/Education[ SHS.ECO ] Humanities and Social Sciences/Economies and financesensenanza[ SHS.EDU ] Humanities and Social Sciences/Education[SHS.ECO]Humanities and Social Sciences/Economics and Financecosto[SHS.ECO] Humanities and Social Sciences/Economics and FinanceComputingMilieux_MISCELLANEOUS

Causes of a Growing Judicial Litigation: Empirical Analysis of a Case

1991

In Spain, judicial litigation has grown considerably since 1959 to 1987, both in absolute and relative dimensions. This trend is especially accentuated in the criminal and in the contentious-administrative jurisdictional areas. By applying an interdisciplinary (economic, juridical, sociological political …) approach, the characteristics of this phenomenon are summarized in this paper, and their numerous and complex causes are analysed. Some of these causes can be considered socially positive, as they seem connected with a greater economic and social development in the country that allows citizens to appeal more frequently and directly to justice courts; but others show a worsening in the s…

Economics and EconometricsPoliticsActuarial sciencePovertyOrder (exchange)PhenomenonSocial changeAppealEconomicsDeveloping countryPositive economicsEconomic JusticeJournal of Interdisciplinary Economics

Comparative imaging of structure and metabolites in tumours.

1991

A novel technique for metabolic imaging using quantitative bioluminescence and single photon imaging was used to measure the distribution of ATP and lactate in two types of human melanoma xenografts with different radiobiologically hypoxic cell fractions (MF: 45 +/- 17% and EE: 6 +/- 3%; mean +/- SD). The tumours were s.c. grown in nude mice and were used for measurement at volumes of 153-3072 mm3. For metabolic imaging the rapidly frozen tumours were serially sectioned, and each cryosection was brought into contact with a frozen bioluminescent enzyme cocktail using a specially designed glass sandwich system. After thawing section and cocktail the luminescence was started, and light was emi…

Pathologymedicine.medical_specialtyMetaboliteTransplantation HeterologousMice NudeBiologychemistry.chemical_compoundMiceAdenosine TriphosphatemedicineBioluminescenceAnimalsHumansRadiology Nuclear Medicine and imagingRadiosensitivityMelanomachemistry.chemical_classificationMice Inbred BALB CRadiological and Ultrasound Technologymedicine.diagnostic_testMelanomaMetabolismmedicine.diseaseMolecular biologyPhoton countingEnzymechemistryPositron emission tomographyLuminescent MeasurementsLactatesInternational journal of radiation biology

Circulating diphtheria antitoxin levels in children aged 11-14 years in relation to the vaccinal history.

1991

Diphtheria antitoxin level in serum samples obtained from 204 healthy children aged 11-14 years was determined by means of an indirect haemagglutination technique and related to the vaccinal history of the subjects. Irrespective of the time since the last toxoid inoculation, the mean antitoxin titre per ml of serum in the individuals who had received incomplete/irregular anti-diphtheria vaccination in childhood was significantly higher when the number of toxoid doses was higher (from two to more than four doses); the same was not observed for individuals given primary vaccination (three toxoid doses) according to the schedule for childhood vaccination in Italy (regular vaccinees) and one or…

HemagglutinationAdolescentDiphtheria ToxoidPhysiologycomplex mixturesSerologyMedicineHumansChildSicilyImmunization ScheduleGeneral VeterinaryGeneral Immunology and Microbiologybiologybusiness.industryDiphtheriaVaccinationPublic Health Environmental and Occupational HealthToxoidHemagglutination Testsmedicine.diseasebiology.organism_classificationDiphtheria AntitoxinVaccinationTiterInfectious DiseasesTasaImmunologyMolecular MedicineAntitoxinbusinessVaccine

LC-Polymers with Axial Chirality

1991

Abstract Liquid crystalline polymers with axial chirality are prepared. These polymers are chiral, not due to a single asymmetric carbon atom, but due to a larger molecular fragment, which is chiral as a whole. They exhibit cholesteric and chiral smectic C* phases. Dielectric spectroscopy proves strong ferroelectric properties in the chiral smectic C* phases of these polymers.

chemistry.chemical_classificationQuantitative Biology::BiomoleculesMaterials scienceStereochemistryLiquid crystallineHigh Energy Physics::LatticeHigh Energy Physics::PhenomenologyPolymerFerroelectricityDielectric spectroscopyCondensed Matter::Soft Condensed MatterCondensed Matter::Materials ScienceCrystallographychemistryAsymmetric carbonAxial chiralityChirality (chemistry)Molecular Crystals and Liquid Crystals

Conditional measures and their applications to fuzzy sets

1991

Abstract Given a ⊥-decomposable measure with respect to a continuous t-conorm, as introduced by the author in an earlier paper (see Section 1), we can construct ⊥-conditional measures as implications. These fulfil a ‘generalized product law’ replacing the product in the classical law by any other strict t-norm ⊥ and turn out to be decomposable with respect to an operation ⊥ V depending on ⊥, ⊥ and the condition set V (Section 2). More general, conditional measures are introduced axiomatically and are shown to be ⊥-conditional measures with respect to some ⊥-decomposable measure (Section 3). ‘Bayesian-like’ models are given which are alternatives to that presented by the author in a recent p…

AlgebraSet (abstract data type)Artificial IntelligenceLogicSection (archaeology)Product (mathematics)Fuzzy setCalculusInformation measureConstruct (python library)Bayesian inferenceMeasure (mathematics)MathematicsFuzzy Sets and Systems

Theory of quadrupole detection fourier transform-ion cyclotron resonance

1991

Abstract The theoretical basis of the recently introduced quadrupole detection Fourier transform-ion cyclotron resonance technique is developed by use of the concept of image charges induced in the detection electrodes. The appearance of resonances at frequencies 2ω+, 2ω−, (ω+ + ω−) and (ω+ − ω−) is explained. The new method is compared with the standard (dipole) detection scheme. Techniques are suggested allowing the simultaneous determination of all resonance frequencies ω+ (perturbed, or reduced, cyclotron frequency), ω− (magnetron frequency) and ωz (trapping frequency).

ChemistryCyclotronCyclotron resonanceAnalytical chemistryResonanceIon cyclotron resonance spectrometryFourier transform ion cyclotron resonancelaw.inventionsymbols.namesakeFourier transformlawQuadrupolesymbolsAtomic physicsSpectroscopyIon cyclotron resonanceInternational Journal of Mass Spectrometry and Ion Processes

Autonomic and cortical responses during anticipation of a sensory task and of feedback from task results

1991

Neuropsychology and Physiological PsychologyPhysiology (medical)General NeuroscienceSensory systemPsychologySocial psychologyAnticipationTask (project management)Cognitive psychologyInternational Journal of Psychophysiology

Systemic Treatment with Interferon-α2B: An Effective Method to Prevent Sterility after Bilateral Mumps Orchitis

1991

In men orchitis represents the most common complication of mumps infection and occurs in 5 to 37% of this population. Bilateral manifestation is observed in 16 to 65% of the patients. The most important danger is the risk of testicular atrophy which results in sterility. Four patients with bilateral mumps orchitis received systemic treatment with interferon-alpha 2B (3 x 10(6) IU per day) for 7 days. All acute symptoms of mumps orchitis disappeared within 2 to 4 days of hospitalization. During 6 to 15 months of followup no incidence of testicular atrophy was observed. In 3 of 4 patients pre-treatment examination revealed subfertility (oligoasthenospermia), while 2 to 4 months after interfer…

AdultMalemedicine.medical_specialtyUrologyPopulationAlpha interferonOrchitisInterferon alpha-2TestismedicineHumansProspective StudiesRadionuclide ImagingAdverse effecteducationMumpsInfertility MaleInterferon alfaAcetaminophenUltrasonographyeducation.field_of_studyPalpationTesticular atrophybusiness.industryInterferon-alphamedicine.diseaseRecombinant ProteinsSurgeryConcomitantDrug EvaluationOrchitisComplicationbusinessmedicine.drugJournal of Urology

The quantum relativistic harmonic oscillator: generalized Hermite polynomials

1991

A relativistic generalisation of the algebra of quantum operators for the harmonic oscillator is proposed. The wave functions are worked out explicitly in configuration space. Both the operator algebra and the wave functions have the appropriate c→∞ limit. This quantum dynamics involves an extra quantization condition mc2/ωℏ = 1, 32, 2, … of a topological character.

PhysicsQuantization (physics)Operator algebraQuantum harmonic oscillatorQuantum dynamicsQuantum mechanicsGeneral Physics and AstronomyCreation and annihilation operatorsCoherent statesTransition of stateSecond quantizationMathematical physicsPhysics Letters A

Fibrinolytic parameters in normotensive pregnancy with intrauterine fetal growth retardation and in severe preeclampsia

1991

In pregnancy a decrease in fibrinolytic activity, which is due to an increase in plasminogen activator inhibitor activity and plasminogen activator inhibitor type 1 and type 2, has been described. Because the placenta is a source of both type 1 and type 2 plasminogen activator inhibitor, we have studied them and other fibrinolytic parameters in a group of normotensive pregnant women with intrauterine fetal growth retardation and in two groups of women with preeclampsia, with or without intrauterine growth retardation. A significant increase in plasminogen activator inhibitor type 1 antigen and plasminogen activator inhibitor activity was observed in preeclampsia, with or without intrauterin…

Adultmedicine.medical_specialtymedicine.medical_treatmentBlood PressurePreeclampsiaPre-EclampsiaAntigenPregnancyReference ValuesInternal medicinePlacentaFibrinolysismedicineFetal growthHumansPregnancyFetal Growth Retardationbusiness.industryFibrinolysisObstetrics and Gynecologymedicine.diseaseUrokinase-Type Plasminogen ActivatorPathophysiologyPlasminogen Inactivatorsmedicine.anatomical_structureEndocrinologyTissue Plasminogen ActivatorImmunologyFemalebusinessPlasminogen activatorAmerican Journal of Obstetrics and Gynecology

On the influence of the physico-chemical properties of aerosols on the life cycle of radiation fogs

1991

A one-dimensional model of radiation fog with detailed microphysics is presented. Aerosols and cloud droplets are treated in a joint two-dimensional size distribution. Radiative fluxes are calculated as functions of the radiative properties of the time-dependent particle spectra. The droplet growth equation is solved by considering radiative effects. Turbulence is treated by means of a higher order closure model. The interaction between the atmosphere and the earth's surface is explicitly simulated. Three numerical sensitivity studies are performed to investigate the impact of the different physico-chemical properties of urban, rural and maritime aerosols on fog formation. Numerical results…

Fluid Flow and Transfer ProcessesAtmospheric ScienceEnvironmental EngineeringMaterials scienceMeteorologyMicrophysicsTurbulencePlanetary boundary layerMechanical EngineeringMechanicsRadiationAtmospheric sciencesPollutionAerosolAtmosphereFogAtmospheric radiative transfer codesLiquid water contentRadiative transferEnvironmental scienceParticlePhysics::Atmospheric and Oceanic PhysicsBoundary-Layer Meteorology

Calculation of the neutrinoless ββ decay of 76Ge using a quark model with harmonic confinement

1991

Abstract The half-life of the neutrinoless double beta decay of 76Ge into the ground state of 76Se is calculated in a relativistic quark confinement model. The proton-neutron quasi-particle random-phase approximation is used to evaluate the s- and p-wave nuclear matrix elements contained in the decay amplitude. We avoid the closure approximation and calculate the effective vector and axial-vector coupling constants of the hadronic currents using our quark model. In our formulation the recoil matrix element arises from the quark recoil in the decaying neutrons. The recoil and the p-wave effect are discussed and compared with other calculations. From the experimental lower bound for the decay…

PhysicsQuarkNuclear and High Energy PhysicsTop quarkParticle physicsHigh Energy Physics::PhenomenologyNuclear TheoryNuclear physicsMAJORANARecoilDouble beta decayHigh Energy Physics::ExperimentNeutronColor confinementNeutrinoNuclear ExperimentNuclear Physics A

Immunohistochemical evaluation of bone marrow lymphoid nodules in chronic myeloproliferative disorders

1991

One hundred and seventy bone marrow biopsies from patients with chronic myeloproliferative disorders (CMPDs) were evaluated for the presence of lymphoid nodules (LNs) and were immunostained using a panel of monoclonal antibodies (UCHL1, 4KB5 and L26) recognizing different lymphocyte antigens. LNs were found in 35% of cases of idiopathic thrombocythaemia, 24.6% of myelofibrosis/osteomyelosclerosis, 18.2% of polycythaemia vera 12.1% of chronic myeloid leukaemia and 19.2% of borderline cases. Varying degrees of immunohistochemical positivity for the three antibodies tested were found. LNs were always made up of variable proportions of both T- and B-lymphocytes with a prevalence of T-cells. Thi…

MalePolycythaemiaPathologymedicine.medical_specialtymedicine.drug_classMonoclonal antibodyPathology and Forensic MedicineBone Marrowhemic and lymphatic diseasesmedicineHumansLymphocytesMyelofibrosisMolecular BiologyAgedMyeloproliferative Disordersintegumentary systembiologybusiness.industryAntibodies MonoclonalCell BiologyGeneral MedicineMiddle Agedmedicine.diseaseImmunohistochemistryChronic myeloproliferative disordersmedicine.anatomical_structureChronic DiseaseMonoclonalbiology.proteinImmunohistochemistryFemaleBone marrowAntibodybusinessVirchows Archiv A Pathological Anatomy and Histopathology

High-spin states in 121Ba and deformation-dependent alignments

1991

The high-spin structure of 121Ba has been investigated by in-beam gamma-ray spectroscopic techniques. Rotational bands based on the h11/2, g7/2 and tentatively d5/2 quasineutron configurations have ...

PhysicsNuclear and High Energy PhysicsSpin statesCondensed matter physics010308 nuclear & particles physicsAstrophysics::High Energy Astrophysical PhenomenaAstrophysics::Cosmology and Extragalactic AstrophysicsDeformation (meteorology)01 natural sciences0103 physical sciencesAstrophysics::Solar and Stellar AstrophysicsAtomic physics010306 general physicsAstrophysics::Galaxy AstrophysicsNuclear Physics A

The Jervell and Lange-Nielsen syndrome.

1991

Deafness and electrocardiographic changes (prolongation of the Q-T interval and inversion of the T wave) with a clinical picture of syncopal attacks and sudden death, were described as a distinct syndrome by Jervell and Lange-Nielsen in 1957. The syndrome is inherited as an autosomal recessive trait. In this study, all the cases reported since 1957 and their proposed prevalence are reviewed. The authors describe the 4 cases they have studied, all of which presented congenital sensorineural hearing loss and electrocardiographic changes characteristic of the syndrome. The relatively high number of cases they have encountered casts doubt on literature that states that the syndrome occurs more …

Malemedicine.medical_specialtyPediatricsHeart diseaseElectrodiagnosisDeafnessSudden deathAutosomal recessive traitElectrocardiographyAudiometryLange-nielsen syndromemedicineCongenital sensorineural hearing lossHumansmedicine.diagnostic_testbusiness.industryInfantGeneral Medicinemedicine.diseaseSurgeryJervell and Lange-Nielsen syndromeLong QT SyndromeOtorhinolaryngologyPediatrics Perinatology and Child HealthFemalebusinessElectrocardiographyInternational journal of pediatric otorhinolaryngology

Infantile neuroaxonal dystrophy: Diagnosis by skin biopsy

1991

A child who shows progressive motor and mental deterioration after the first year of life, who has pyramidal signs, marked muscle hypotonia, but no seizures, suggests to have infantile neuroaxonal dystrophy (INAD). Beyond the age of two years, the EEG also entails characteristic findings. Diagnosis may be obtained by an ultrastructural examination of biopsied skin. The respective clinical and morphological findings are recorded and illustrated from four patients in this report.

MalePathologymedicine.medical_specialtyMuscle HypotoniaBiopsySural nerveInfantile neuroaxonal dystrophyDegenerative diseaseDevelopmental NeuroscienceBiopsyHumansMedicineSkinmedicine.diagnostic_testMental deteriorationbusiness.industryLeukodystrophyInfantPeripheral Nervous System DiseasesNeuromuscular DiseasesGeneral Medicinemedicine.diseaseChild PreschoolPediatrics Perinatology and Child HealthSkin biopsyFemaleNeurology (clinical)businessBrain and Development

Extrapyramidal Symptoms and their Relationship to Clinical Efficacy under Perphenazine Treatment*

1991

In order to verify the hypothesis of a strict relationship between clinical improvement and extrapyramidal side-effects, especially micrographia, twenty-two acutely ill schizophrenics were treated with perphenazine in a controlled prospective 28-day trial. During the study period, psychopathometric data, prolactin plasma levels, and handwriting samples were collected. According to the remission criteria fixed before the study began (both BPRS ≤ 25 and GAS ≥ 80 points), 45.5% (10/22) of the total patient sample were classified as treatment responders. Handwriting tests were quantified in 21 patients. "Positive" handwriting results, i. e., a reduction of at least 13% in the overall area of 50…

GynecologyPerphenazinemedicine.medical_specialtyGeneral MedicinePsychiatry and Mental healthExtrapyramidal symptomsHandwritingmedicinePharmacology (medical)Clinical efficacymedicine.symptomPsychologyNeurosciencemedicine.drugPharmacopsychiatry

Kinetic studies on protoporphyrinogen oxidase inhibition by diphenyl ether herbicides

1991

Diphenyl ethers (DPEs) and related herbicides are powerful inhibitors of protoporphyrinogen oxidase, an enzyme involved in the biosynthesis of haems and chlorophylls. The inhibition kinetics of protoporphyrinogen oxidase of various origins by four DPEs, (methyl)-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (acifluorfen and its methyl ester, acifluorfen-methyl), methyl-5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-chlorobenzoate (LS 820340) and methyl-5-[2-chloro-5-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (RH 5348), were studied. The inhibitions of the enzymes from maize (Zea mays) mitochondrial and etiochloroplastic membranes and mouse liver mitochondrial membranes were com…

0106 biological sciencesOxidoreductases Acting on CH-CH Group DonorsStereochemistry[SDV]Life Sciences [q-bio]Carboxylic acidMitochondria LiverEtherSaccharomyces cerevisiaeAcifluorfen01 natural sciencesBiochemistryMitochondrial ProteinsMiceStructure-Activity Relationship03 medical and health scienceschemistry.chemical_compoundMALHERBOLOGIEPhenolsAnimalsProtoporphyrinogen OxidaseMolecular BiologyComputingMilieux_MISCELLANEOUS030304 developmental biologychemistry.chemical_classification0303 health sciencesTrifluoromethylFlavoproteinsHerbicidesDiphenyl etherIntracellular MembranesCell BiologyPlantsMitochondriaProtoporphyrinogen IX[SDV] Life Sciences [q-bio]KineticsEnzymechemistryProtoporphyrinogen oxidaseOxidoreductasesEthersResearch Article010606 plant biology & botanyBiochemical Journal

Ah receptor mediating induction of cytochrome P450IA1 in a novel continuous human liver cell line (Mz-Hep-1)

1991

Abstract The Ah receptor regulates induction of cytochrome P450IA1 and mediates certain toxicities of polyhalogenated aromatics such as 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD). It has been characterized previously in continuous cell lines, notably the mouse hepatoma line Hepa 1, the human squamous cell carcinoma line A431, and the human liver cell line Hep G2. The present work extends our knowledge of the Ah receptor in continuous human liver cell lines. Ah receptor can be detected in Mz-Hep-1, a hepatitis B virus-negative cell line derived from a Thorotrast-induced hepatocellular carcinoma. The mean concentration of Ah receptor in Mz-Hep-1 cells was 341 ± 22 fmol/mg cytosol protein (m…

PharmacologyReceptor complexChemistryEstrogen receptorBiochemistryHep G2Dissociation constantGlucocorticoid receptorMechanism of actionBiochemistryCell culturemedicinemedicine.symptomGlucocorticoidmedicine.drugBiochemical Pharmacology

GABA, receptor mediated fast synaptic inhibition in the rabbit brain-stem respiratory system

1991

The involvement of GABA mediated neurotransmission in the central control of respiration was investigated by administration of the specific GABAA receptor agonist muscimol and the specific GABAA receptor antagonist biculline into the fourth cerebral ventricle of the rabbit. Cycle-triggered averaging of the phrenic nerve activity (PNA) was used to quantify drug-induced changes of the central respiratory pattern. Muscimol reduced the peak amplitude of PNA and increased the duration of the respiratory phases. High amounts of muscimol led to a long-lasting but reversible central apnea. Bicuculline very effectively blocked the effects of externally applied muscimol. Blockade of intrinsically act…

Agonistmedicine.medical_specialtyPhysiologymedicine.drug_classIn Vitro TechniquesBiologyNeurotransmissionBicucullineSynaptic Transmissionchemistry.chemical_compoundInternal medicinemedicineAnimalsRespiratory systemInjections IntraventricularGallamine TriethiodideMuscimolGABAA receptorRespirationmusculoskeletal neural and ocular physiologyRespiratory centerNeural InhibitionRespiratory CenterBicucullineReceptors GABA-APhrenic NerveEndocrinologynervous systemMuscimolchemistryControl of respirationSynapsesRabbitsNeurosciencemedicine.drugActa Physiologica Scandinavica

Selection of biological and chemical parameters indicating or affecting the vitality of Norway spruce

1991

Abstract Thirty-two young and old Norway spruce trees ( Picea abies (L.) Karst.) showing different degrees of damage were investigated in a forest stand in the Taunus Mountains (FRG). The old trees showed visual symptoms of damage such as discolouration of the needles and needle loss. Over 70 biometric, physiological and chemical parameters were determined for needle and soil samples. Interrelationships between these variables were described by correlation analysis. The most discriminant variables between different groups of trees were found by Fisher weighing. This reduced data set was used for principal component analysis and for the classification of various parameters according to diffe…

Environmental EngineeringbiologySoil testEcologyPicea abiesbiology.organism_classificationVitalityPollutionHorticultureNutrientSoil pHPrincipal component analysisEnvironmental ChemistryGenetic variabilityWaste Management and DisposalSelection (genetic algorithm)Science of The Total Environment

The duodenum in liver cirrhosis: endoscopic, morphological and clinical findings.

1991

Endoscopic studies were performed to determine whether changes occurred in the duodenum related to portal hypertension in patients with liver cirrhosis. The total of 271 patients studied were subdivided into three groups: 83 patients with liver cirrhosis and portal hypertension, 53 with liver cirrhosis but no portal hypertension, and 135 controls. In the duodenum of cirrhotic patients with portal hypertension several changes were observed on endoscopy that were also present in the other two groups. Atrophy and vascular malformations, however, were present only in the duodenum of cirrhotic patients with portal hypertension, although in only a few patients and with statistical significance on…

Liver CirrhosisMalemedicine.medical_specialtyCirrhosisDuodenumGastroenterologyAtrophyEsophageal varicesDuodenitisInternal medicineHypertension PortalmedicineHumansEndoscopy Digestive SystemIntestinal MucosaAgedmedicine.diagnostic_testbusiness.industryGastroenterologyMiddle Agedmedicine.diseaseEndoscopymedicine.anatomical_structureDuodenumPortal hypertensionBlood VesselsFemaleComplicationbusinessEndoscopy

La escuela com unidad de produccion

1991

International audience

unidad de produccion[SHS.EDU]Humanities and Social Sciences/Education[SHS.EDU] Humanities and Social Sciences/Education[ SHS.ECO ] Humanities and Social Sciences/Economies and finances[ SHS.EDU ] Humanities and Social Sciences/Education[SHS.ECO]Humanities and Social Sciences/Economics and Finance[SHS.ECO] Humanities and Social Sciences/Economics and FinanceComputingMilieux_MISCELLANEOUSescuela

Nonlinear Critical Layers in Barotropic Stability

1991

Abstract Applying the method of matched asymptotic expansions (MAE) to the shallow water equations on a rotating sphere, the structure of critical layers that occur in the linear and inviscid analysis of neutral disturbances of barotropic zonal flows is investigated, assuming that the critical layers are controlled by nonlinearity rather than viscosity or nonparallel flow effects. It turns out that nonlinearity is insufficient to resolve the critical layer singularity completely. It suffices however to connect linear and nondissipative solutions across critical latitudes.

PhysicsAtmospheric Sciencebusiness.industryMechanicsMethod of matched asymptotic expansionsPhysics::Fluid DynamicsNonlinear systemViscositySingularityOpticsFlow (mathematics)Inviscid flowBarotropic fluidbusinessShallow water equationsPhysics::Atmospheric and Oceanic PhysicsJournal of the Atmospheric Sciences

Photon absorption by aqueous TiO2 dispersion contained in a stirred photoreactor

1991

We present a simple experimental method which allows the evaluation of the absorbed photon flow. The method is based on measurements of transmitted photon rates (by means of standard actinometer solutions) for different reactor thicknesses and/or catalyst concentrations. The method was applied to phenol degradation reaction carried out in a stirred batch phtotoreactor containing aqueous TiO 2 (anatase) dispersion, directly irradied by a 1,500 W Xe lamp

AnataseEnvironmental EngineeringPhotonAqueous solutionActinometerChemistryGeneral Chemical EngineeringAnalytical chemistryPhotochemistryPhenol degradationCatalysislaw.inventionlawDispersion (chemistry)Absorption (electromagnetic radiation)BiotechnologyAIChE Journal

LC n Compacta are n -Improved

1991

Discrete mathematicsGeneral MathematicsMathematicsBulletin of the London Mathematical Society

Ion-exchange high-performance liquid chromatography of nucleotides and polypeptides on new types of ion-exchange sorbents, based on polystyrene-coate…

1991

A novel type of ion exchanger was prepared by multipoint covalent binding of polystyrene chains onto the surface of porous silica followed by polymer-analogous modification of the bonded layer. Both anion and cation exchangers were synthesized and examined in the separation of nucleotides and proteins. Rapid and efficient separation of basic polypeptides on strong anion exchangers and that of acidic polypeptides on strong cation exchangers could be achieved. For the separation of complete mixtures of polypeptides the application of zwitter-ionic ion exchangers can be recommended.

Inorganic chemistryCovalent bindingBiochemistryHigh-performance liquid chromatographyAnalytical ChemistryIonchemistry.chemical_compoundAnimalsHumansNucleotidePorosityChromatography High Pressure Liquidchemistry.chemical_classificationChromatographyIon exchangeNucleotidesOrganic ChemistryGeneral MedicineChromatography Ion ExchangeSilicon DioxidechemistryPolystyrenesCattlePolystyreneIon Exchange ResinsPeptidesLayer (electronics)Journal of chromatography

Myristylation is involved in intracellular retention of hepatitis B virus envelope proteins

1991

The envelope of hepatitis B virus contains three related proteins, one of which is myristylated. The nonmyristylated small and middle protein are assembled into empty envelope particles which are secreted from cells, whereas the myristylated large envelope protein is mainly found in complete virions and is not secreted in the absence of the nucleocapsid. The block to secretion can be partially overcome by mutation or deletion of the myristylation site. Creation of a myristyl attachment site in the small protein impairs the secretion of empty envelope particles but not their intracellular assembly. Myristylation may therefore play a crucial role in hepatitis B virus replication by channeling…

Hepatitis B virusvirusesDNA Mutational AnalysisImmunologyIn Vitro TechniquesBiologyVirus Replicationmedicine.disease_causeMyristic AcidMicrobiologyVirusStructure-Activity RelationshipCapsidViral Envelope ProteinsViral envelopeVirologymedicineHumansSecretionProtein PrecursorsHepatitis B virusMutationHepatitis B Surface Antigensbiology.organism_classificationVirologyCell CompartmentationMolecular WeightCapsidHepadnaviridaeViral replicationInsect ScienceMyristic AcidsProtein Processing Post-TranslationalResearch ArticleJournal of Virology

N-acetyl-L-glutamate in brain: assay, levels, and regional and subcellular distribution.

1991

N-Acetyl-L-glutamate (NAG), the activator of mitochondrial carbamoyl phosphate synthetase (CPS), is demonstrated by several methods, including a new HPLC assay, in the brain of mammals and of chicken. The brain levels of NAG are 200-300 times lower than the levels of N-acetyl-L-aspartate (NAA), and are similar to the levels of NAG in rat liver. The NAG levels in chicken liver are very low. Although NAG is mitochondrial in the liver, it is cytosolic in brain. Using enzyme activity and immuno assays we did not detect CPS in brain (detection limit, 12.5 micrograms/g brain), excluding that brain NAG is involved in citrullinogenesis. The regional distribution of brain NAG differs from that of NA…

MaleCentral nervous systemurologic and male genital diseasesBiochemistryCellular and Molecular NeuroscienceMiceGlutamatesSpecies SpecificitymedicineAnimalsChromatography High Pressure Liquidchemistry.chemical_classificationN acetyl L glutamateBrain ChemistryAspartic AcidSheepbiologyurogenital systemActivator (genetics)Rats Inbred StrainsGeneral MedicineCarbamoyl phosphate synthetaseEnzyme assayRatsCytosolSubcellular distributionEnzymemedicine.anatomical_structurechemistryBiochemistrybiology.proteinChickensNeurochemical research

Complexes hétéronucléaires Cp2MM′(Cp)(CO)3 (M  Nb, Ta; M′  Mo, W) avec groupes carbonyles pontants et semi-pontants: synthèse et comportement dynam…

1991

Abstract Heteronuclear structures Cp 2 MM′(Cp)(CO) 3 (M  Nb, Ta; M′  Mo, W) are obtained by heating Cp 2 MH 3 (M  Nb, Ta) with Cp 2 M′ 2 (CO) 6 (M′  Mo, W) or starting from Cp 2 M(CO)H and Cp 2 M′ 2 (CO) 4 . These heterobimetallic complexes show three CO coordination modes: terminal, semi-bridging and bridging. The two cyclopentadienyl groups of the Cp 2 M moiety are anisochronous owing to molecular rigidity; rotation barriers around the MM′ bond have been estimated and are greatest with tantalum derivatives.

StereochemistryOrganic ChemistryTantalumchemistry.chemical_elementNuclear magnetic resonance spectroscopyIon pairsBiochemistryInorganic ChemistryCrystallographychemistry.chemical_compoundchemistryCyclopentadienyl complexHeteronuclear moleculeMaterials ChemistryMoietyPhysical and Theoretical ChemistryMetalloceneJournal of Organometallic Chemistry

Phylogeny of viroids, viroidlike satellite RNAs, and the viroidlike domain of hepatitis delta virus RNA.

1991

We report a phylogenetic study of viroids, some plant satellite RNAs, and the viroidlike domain of human hepatitis delta virus RNA. Our results support a monophyletic origin of these RNAs and are consistent with the hypothesis that they may be "living fossils" of a precellular RNA world. Moreover, the viroidlike domain of human hepatitis delta virus RNA appears closely related to the viroidlike satellite RNAs of plants, with which it shares some structural and functional properties. On the basis of our phylogenetic analysis, we propose a taxonomic classification of these RNAs.

GeneticsMultidisciplinaryPhylogenetic treeRNABiologyVirusoidVirologyModels BiologicalVirusViroidsDomain (software engineering)MonophylyPhylogeneticsRNARNA SatelliteRNA ViralHepatitis Delta VirusLiving fossilPhylogenyResearch Article

Mismatch negativity — Factors affecting its variation

1991

Neuropsychology and Physiological PsychologyVariation (linguistics)Physiology (medical)General NeuroscienceStatisticsMismatch negativityPsychologyInternational Journal of Psychophysiology

Independent and cumulative yields of very neutron-rich nuclei in 20 MeVp- and 18–41 MeVd-induced fission ofU238

1991

Independent and cumulative yields in nearly symmetric fission have been measured for the first time by bombarding $^{238}\mathrm{U}$ with 20-MeV protons and with 18-, 25-, and 41-MeV deuterons. Isobaric charge dispersion has been determined in the A=110, A=112, and A=114 mass chains and, from asymmetric fission, in the A=80 mass chain. The average isobaric charges in the p+U reaction were 44.01\ifmmode\pm\else\textpm\fi{}0.20 (A=110), 45.15\ifmmode\pm\else\textpm\fi{}0.15 (A=112), and 45.74\ifmmode\pm\else\textpm\fi{}0.15 (A=114). The widths (standard deviations) of the charge dispersion curves were 0.82\ifmmode\pm\else\textpm\fi{}0.08 (A=112) and 0.54\ifmmode\pm\else\textpm\fi{}0.08 (A=114…

Nuclear reactionPhysicsNuclear and High Energy PhysicsIsotopes of germanium010308 nuclear & particles physicsQ valueFissionOrder (ring theory)Charge (physics)7. Clean energy01 natural sciencesNuclear physicsIsotopes of palladium0103 physical sciencesNeutronAtomic physics010306 general physicsPhysical Review C

Age-related accumulation of congophilic fibrillar inclusions in endocrine cells

1991

Intracellular fibrillar congophilic inclusions are well known as neurofibrillary tangles in neurons and as Biondi bodies in choroid plexus epithelial cells. Recently similar amyloid-like inclusions in adrenal cortical cells were described (Eriksson and Westermark 1990). This study on 150 adrenal glands confirms these observations. In our material the age-related accumulation of congophilic inclusions starts earlier (in the sixth decade) and reaches a higher incidence (42.7%). We found similar intracellular inclusions in other endocrine organs, for example in the anterior lobe of the pituitary, in the cells of parathyroid glands and in Sertoli cells. The age-related incidence of these fibril…

AgingAmyloidPituitary glandmedicine.medical_specialtyPathologyEnteroendocrine cellBiologyTesticlePathology and Forensic MedicineEndocrine GlandsInternal medicineAdrenal GlandsmedicineHumansEndocrine systemMolecular BiologyBrain ChemistryAdrenal glandCongo RedCell BiologyGeneral MedicineSertoli cellmedicine.anatomical_structureEndocrinologyPituitary GlandChoroid PlexusNeurofibrilsChoroid plexusExtracellular SpaceEndocrine glandVirchows Archiv A Pathological Anatomy and Histopathology

Characterization of prejunctional muscarinic autoreceptors in the guinea-pig trachea

1991

1. The effects of ten muscarinic antagonists on electrically evoked [3H]-acetylcholine release and muscle contraction were compared in an epithelium-free preparation of the guinea-pig trachea that had been preincubated with [3H]-choline. 2. The M3-selective antagonists UH-AH 37, 4-diphenyl-acetoxy-N-piperidine methobromide and para-fluorohexahydrosiladiphenidol were more potent in reducing the contractile response than in facilitating the evoked [3H]-acetylcholine release. Hexahydrosiladiphenidol did not discriminate between pre- and postjunctional effects. The rank order of the postjunctional potencies of the ten antagonists as well as the postjunctional pA2 values obtained for hexahydrosi…

medicine.medical_specialtyGuinea PigsIn Vitro TechniquesBiologyCholinechemistry.chemical_compoundInternal medicineMuscarinic acetylcholine receptormedicineMethoctramineAnimalsReceptorPharmacologyParasympatholyticsMuscarinic acetylcholine receptor M3Muscle SmoothMuscarinic acetylcholine receptor M2Receptors MuscarinicAcetylcholineElectric StimulationTracheaEndocrinologychemistryAutoreceptormedicine.symptomAcetylcholineMuscle ContractionResearch Articlemedicine.drugMuscle contractionBritish Journal of Pharmacology