showing 36 of ~574560 from 574555 documents
On finite element approximation of the gradient for solution of Poisson equation
1981
A nonconforming mixed finite element method is presented for approximation of ?w with Δw=f,w| r =0. Convergence of the order $$\left\| {\nabla w - u_h } \right\|_{0,\Omega } = \mathcal{O}(h^2 )$$ is proved, when linear finite elements are used. Only the standard regularity assumption on triangulations is needed.
false
1981
The dynamical region of the measured calibration curves is investigated using the results of the theory published previously. The kinetic constants of the flow-equilibrium are calculated from the measurements according to two different models for a spontaneous polymer diffusion of the transported P-mer from sol into gel of the Phase Distribution Chromatography (PDC)-column. The corresponding lateral concentration profiles in the gel are found by analytical integration of Fick's second law under the corresponding boundaries. An energetic model of this flow-equilibrium is stated, giving the activation enthalpy and -entropy of the rediffusion of the polymer from gel into sol after some retarda…
Identification of conjugation and cleavage products in the thiolytic metabolism of the anticancer drug 4'-(9-acridinylamino)methanesulfon-m-anisidide.
1981
Conjugation and cleavage products in the thiolytic metabolism of the anticancer drug 4′ -(9-acridinyl amino)methanesulfon-m-anisidide were identified primarily by high-pressure liquid chromatography in combination with field desorption mass spectrometry. The spontaneous metabolic pathway of the drug, as related to its susceptibility to nucleophilic attack by endogenous thiols at the 9-carbon atom of the acridine moiety, has been studied. Among the metabolite fraction of 4′-(9-acridinylamino)methanesulfon-m-anisidide excreted in rat bile after administration of a therapeutic dose, a conjugate was identified as the 9-acridinyl thioether of glutathione. This conjugation product and the corresp…
PHOSPHORORGANISCHE VERBINDUNGEN 97: Die Diphenylphosphinyl- und die Diphenylthiophosphinylgruppe als selektive Schutzgruppe für die Mercaptofunktion.…
1981
Abstract Diphenylphosphinsaurecyanid und Diphenylthiophosphinsaurecyanid reagieren selektiv mit der Mercaptogruppe—auch bei Anwesenheit von Verbindungen mit primaren Aminogruppen. Die Thioloesterbindung in Thiophosphin-, Thiophosphon- und Thiophosphorsaure-S-estern wird durch nicht solvatisierte Fluoridionen ([R4N]F°3 H2O (R = C4H9) und CsF) unter schonenden Bedingungen in Chloroform, Methylenchlorid oder THF gespalten. (C6H5)2P(O)CN und (C6H5)2P(S)CN sind als Schutzgruppen-Reagentien fur Mercaptane geeignet. Diphenylphosphinsaurechlorid und Diphenylthiophosphinsaurechlorid sind in Konkurrenzversuchen mit Butylamin/Butylmercaptan N-selektiv. Bei Cysteamin und Cysteinmethylester wird aber im…
Social differenciation and higher education : the french case
1981
International audience
Inferencia bayesiana sobre el coeficiente de correlacion de una poblacion normal bivariante
1981
En el presente articulo se utiliza el metodo de maximizacion de la informacion desconocida para deducir las distribuciones inicial y final de referencia cuando se trata de hacer inferencias sobre el coeficiente de correlacion de una poblacion normal bivariante
Luminance threshold for stereopsis.
1981
Interaction of atenolol with furosemide and calcium and aluminum salts
1981
Six healthy subjects were treated with 100 mg atenolol. After a therapy-free interval of 4 wk the same subjects received the same dose of atenolol with furosemide, 40 mg, with calcium (as the lactate gluconate and carbonate), 500 mg, or with aluminum hydroxide, 5.6 gm. Atenolol alone and in combination was administered first as a single oral dose; a long-term 6-day treatment began 48 hr later. Addition of furosemide did not influence atenolol kinetics, but aluminum hydroxide led to an insignificant reduction (P greater than 0.05) of mean peak plasma levels of about 20% and of the area under the plasma concentration-time curve (AUC -infinity) from 5818 to 4353 ng ml-1 hr (P greater than 0.05…
Study of pituitary secretion in relation to retinopathy in patients with juvenile diabetes mellitus.
1981
Fifteen juvenile diabetic patients with normal eye fundus, 6 with non proliferative retinopathy, 5 with proliferative retinopathy and 5 healthy control subjects were studied in order to investigate pituitary function in relation to diabetic retinopathy. ACTH values at 08(00) and 18(00), hPRL and TSh secretion in response to 200 microgram TRH i.v., and GH secretion in response to 500 mg oral L-dopa were evaluated. In all diabetic subjects, 08(00) ACTH levels were lower than in controls. Basal hPRL, TSH and GH values of the diabetics did not differ from those of the controls. No significant differences were found in hPRL levels in response to TRH, whereas significantly lower TSH responses wer…
false
1981
The anionic polymerization of tert-butyl methacrylate (TBMA) in tetrahydrofuran, using Na+ and Cs+ as counterions proceeds without side reactions even at room temperature. The resulting molecular weight distributions are nearly monodisperse (Mw/Mn ⩽ 1,01). The rate constants for the propagation of ion pairs were measured in the range from + 15 to −100°C. The Arrhenius plots are linear, but different for the two counterions, resulting in the following numerical values for the frequency exponent A and the activation energy Ea: A = 8,5 and Ea = 7,2 kcal/mol = 30 kJ/mol for Na+; A = 9,5 and Ea = 5,6 kcal/mol = 23 kJ/mol for Cs+. The difference between the counterions, which is in contrast to th…
Frutex y caminos nodales
1981
Dado un grafoG=(X, E) con un solo vertice insaturadop, se estudia el problema de encontrar, para todox∈X, un caminoM-alternado par que unax conp. Se halla un algoritmo, y se plantea su aplicacion cara a dar una variante del Algoritmo de Edmonds en la que no haya que contraer los pseudovertices.
Gesangsformen und Verwandtschaft der asiatischen ZilpzalpePhylloscopus collybita abietinus undPh. c. sindianus
1981
Die Territorialgesange zweier geographisch isolierter Zilpzalp-Populationen werden untersucht.Ph. c. abietinus aus dem Elbursgebirge (Iran) ist von skandinavischenc. abietinus und von mitteleuropaischenc. collybita fast nicht verschieden.Ph. c. sindianus aus dem NW-Himalaya verfugt uber Elemente, deren Frequenz zu Beginn ansteigt; sie machen etwa ein Drittel des Element-Repertoires aus.Ph. c. collybita undc. abietinus fehlen solche Elemente, jedoch besitzt sie der sibirischec. tristis in ganz ahnlicher Form.
Der austausch des cyclopentadienylliganden im methylcyclopentadienylmangan(I)tricarbonyl. Untersuchungen zur konkurrierenden komplexbildung mit methy…
1981
Abstract Exchange of the cyclopentadienyl ligand in methylcyclopentadienylmanganese(I) tricarbonyl with methyl-substituted benzenes is catalysed by AlCl 3 + HCl and leads to the cations [arene-Mn(CO) 3 ] + . The methylbenzenes isomerize and disproportionate during the reaction. The distribution of the arenes between the solution and the complex ions has been determined. The different complexing abilities of the arenes lead to the proposal of an associative mechanism for the ligand exchange.
The short-circuited everted sac of rat colon mucosa.
1981
A short-circuited preparation of everted rat colon sacs is described. The serosal current electrode is a AgAgCl wire. A cylindrical agar bridge or AgAgCl electrode may be employed on the mucosal side. Effects of Ag+ ions liberated from the electrodes on ion transport could not be demonstrated. Fluid and sodium are absorbed and bicarbonate secreted. Potassium and chloride movements are not significantly different from zero. The preparation remains stable for at least 2 h. Sodium absorption is diminished by 50% and bicarbonate secretion abolished in the absence of glucose. In principle, similar ion transport properties were found as in Ussing-chamber preparations. The advantage of the everted…
Role of β1H for the binding of C3b-coated particles to human lymphoid and phagocytic cells
1981
Coating of EAC14oxy23b with highly purified human serum beta 1H globulin (beta 1H) led to acceleration of rosette formation with human peripheral blood lymphocytes (PBL), tonsil lymphocytes, B lymphoblastoid (Raji) cells, granulocytes and monocytes. This reaction was discernible from C3bi-dependent rosette formation. Enhancement of rosette formation of C3b cells by beta 1H was most effective at limiting amounts of C3 per EAC14oxy23b. The beta 1H effect was not due to trace contamination with C3b inactivator. beta 1H-dependent rosette formation with the various lymphoid and phagocytic cells could be suppressed by the F(ab')2 fragment of anti-beta 1H suggesting beta 1H-mediated binding of bet…
Induction of anamnestic T cell proliferation by antigen-pulsed, bone marrow-derived macrophages.
1981
Bone marrow-derived macrophages (BMM phi) were grown in a liquid culture system in the presence of L cell-conditioned medium as a source of colony-stimulating factor. After a 4-h pulse with antigen, cultured irradiated BMM phi were capable of presenting the antigen to primed T cells as assessed in a T cell proliferation assay. Proliferation was optimal when BMM phi were used between days 5 and 8 of bone marrow cell culture. T cells of Lyt1 and Lyt123 phenotype had to be present at the start of the culture period to yield an optimal response. Conventional antisera and monoclonal antibodies directed against the H-2 I region and the I-A subregion, respectively, proved inhibitory in this system…
Structures for the synthesis of stable immitances with arbitrary zeros
1981
Positron detrapping from defects: A thermodynamic approach
1981
The rate of positron detrapping in thermal equilibrium from lattice defects has been calculated by relating it to the specific trapping rate. The results for vacancies, dislocations and surfaces each show a different temperature dependence for the escape rate. For vacancies a measure of the importance of the detrapping can be obtained from the ratio of the vacancy formation energy to the positron binding energy in the defect. The positronium desorption rate from a surface is also calculated and agreement with experimental results is found.
Carcinoembryonic Antigen as a Monitor in Breast Cancer
1981
: Carcinoembryonic antigen (CEA) levels were serially determined in 125 patients with breast cancer in order to study the diagnostic and prognostic use of serum CEA levels before and/or after surgery and during treatment with hormonal and chemotherapy. Serum CEA levels were elevated in 15.5% of nonmetastatic patients. Carcinoembryonic antigen increased according to stage (TNM classification); and a direct relationship between positive CEA levels and subsequent recurrence was found. After a three-year postoperative interval a 50% survival rate was exhibited in CEA-positive patients vs an 88% survival rate in those patients found to be CEA negative. There is a definite correlation between the…
false
1981
Theoretical predictions from a non-linear model based on the free volume concept, which were previously tested only with a molten polymer, are presented and compared with literature data of solid polyethylene. The agreement is good both when a steady state is reached in the experimentally explored times and when, on the contrary, the data do not show it. Theoretische Berechnungen des elektrischen Verhaltens von Polymeren anhand eines nichtlinearen Modells, die auf dem Konzept des freien Volumens basieren und bisher lediglich an einem geschmolzenen Polymer getestet wurden, werden vorgestellt und mit Literaturdaten von festem Polyethylen verglichen. Die Ubereinstimmung ist gut, wenn in den ex…
Polycondensed nitrogen heterocycles. X. 5,6,7,8-Tetrahydropyrrolo[1,2-e][1,5]benzodiazocin-7-ones. A new ring system
1981
The synthesis of a new heterocyclic ring system is described. Condensation of 1,4-diketones 1a,b with β-alanine gave the substituted propionic acids 2a,b which upon reduction with palladium on charcoal afforded compounds 3a,b. Title compounds 4a,b were obtained by refluxing 3a,b in toluene with p-toluenesulphonic acid as catalyst.
Darstellung von Oligo[(hydroxy-1,3-phenylen)methylen]en mit Hydroxynitrophenylen- und Alkylhydroxyphenyleneinheiten
1981
Possibilities to synthesize substituted oligo[(hydroxy-1,3-phenylene)methylene]s containing hydroxynitrophenylene and alkylhydroxyphenylene units are discussed. The only successful way to introduce the hydroxynitrophenylene unit consists in the condensation of chloromethylated nitrophenols with an excess of alkylphenols. The resulting compounds can be prolonged stepwise at the alkylhydroxyphenylene end group by alternating hydroxymethylation and further condensation with alkylphenols. Thus, including the hydroxymethylated compounds, 11 dinuclear, 17 trinuclear, and 5 tetranuclear compounds were obtained for the first time. Some of them were characterized by their acetyl derivatives.
Die Kristallstruktur von Triphenylantimonsulfid
1981
Incorporation of ATP synthetase into long-term stable liposomes of a polymerizable synthetic sulfolipid
1981
Eléments pour une politique sociale en matière de carte universitaire
1981
International audience
Atoms embedded in an electron gas: Immersion energies
1981
Energies of atoms, H through Ar, embedded in a homogeneous electron gas are calculated within the density-functional scheme as a function of the electron-gas density. The energy-versus-density curves and the induced densities of states are analyzed and discussed in terms of the interaction properties of an atom with its environment. The low-density limit of the immersion energy is related to the electron-atom scattering length. The results should prove useful in detailed investigations of the recently suggested "quasiatom" or "effective-medium" approaches to chemical binding. The lowest-order estimates of the binding energies of diatomic molecules and chemisorbed atoms are obtained. Peer re…
Deuteron Photodisintegration below 100 MeV
1981
Interaction of cimetidine with metoprolol, propranolol, or atenolol.
1981
Application of a three-dimensional drawing procedure to the evaluation of series of protein samples after analysis by gel electrophoresis and other m…
1981
Effect of Light on the Composition of Mitochondrial Lipids from Hypocotyl Hooks of Bean Seedlings (Phaseolus vulgaris L.).
1981
Summary Mitochondria were isolated and roughly purified from bean seedlings (phaseolus vulgaris) treated with different red light (660 nm) irradiation programmes. Etiolated seedlings were irradiated for short terms or grown in red light. The mitochondria from differently treated seedlings were analysed for their phospholipid and fatty acid patterns. The mitochondrial phospholipid patterns from green and etiolated seedlings were rather similar. This was also valid for the fatty acids from the phospholipid fraction whereas the fatty acid patterns of the glycolipids showed differences. Remarkable changes were observed in the phospholipid pattern of the mitochondrial fraction after short-term i…
Impact of thymus on the generation of immunocompetence and diversity of antigen-specific MHC-restricted cytotoxic T-lymphocyte precursors.
1981
Red blood cell sodium and potassium after hydrochlorothiazide.
1981
In six of seven healthy males 6 days of hydrochlorothiazide (HCT), 50 mg twice daily, without potassium supplements resulted in a rise in red blood cell (RBC) sodium concentration. Serum potassium concentration fell in all subjects. Four days after discontinuing HCT, intracellular sodium and extracellular potassium concentrations had normalized. Throughout the evaluation period the course of mean relative intracellular sodium was almost a mirror image of mean relative extracellular potassium. Thus, either the decline of serum potassium or of HCT (because of its inhibitory effect on Na-K-ATPase activity) might have diminished Na-K-ATPase–dependent active RBC sodium efflux with a resultant ri…
Molecular orbital studies on the mechanism of catalytic isomerization of xylenes III. Protonation channels
1981
Abstract The isoenergetic lines of the interaction energy between a bare proton and ortho-, meta- , and para -xylene have been calculated in order to detect both the best approaching channel and the preferred protonation positions. The channels found direct the protonation to the following ring positions: 4 and 5 for o -xylene, 4 and 6 for m -xylene, and 2 equivalents for p -xylene. The overall interaction energy determines the protonation positions on each isomer and the most important contributions to it are the electrostatic term in o -xylene, the polarization term in p -xylene, and both terms equally in m -xylene. These results are in agreement with the experimental findings and appear …
Treatment of Idiopathic Varicoceles by Transfemoral Testicular Vein Occlusion
1981
Percutaneous transfemoral occlusion of the testicular vein is a new alternative in the treatment of idiopathic varicocele. Embolization with the Gianturco coil was done on 27 patients. The occlusion was performed immediately after diagnostic phlebography. The results of followup for 1 year are available for 18 patients. In 1 patient the coil had to be removed because of persistent pain, although cause and effect could not be proved. Two patients had a recurrence. The urographic findings were normal 1 year after embolization. No dislocation of the foreign body was observed. Two patients reported that their wives were pregnant.
Detection of stationary objects by the blind Cave FishAnoptichthys jordani (Characidae)
1981
It was noticed that the blind Mexican Cave Fish repeatedly passes along objects new to it at a short distance. Observations and experiments are reported which support the hypothesis that water movements occurring between the stationary object and the fish as it passes by convey information about the location and possibly the shape of the object, which is detected by the lateral line organ of the fish. Water movements of the expected type were recorded with the help of a model fish equipped with a mechano-electric analogue of a free neuromast.
The action of iontophoretically applied acetylcholine and dopamine on single claustrum neurones in the cat.
1981
Abstract The effects of iontophoretically applied acetyl-choline (ACh) and dopamine (DA) on spontaneously active claustral neurones, in chloralose-anaesthetised cats, have been investigated. Acetylcholine had both facilitatory and inhibitory effects in almost the same proportions. The action of DA was prevalently inhibitory. Two types of inhibitory response to ACh and DA are described: short-lasting inhibition and long-lasting inhibition. The excitatory response always outlasted the period of drug application.