showing 36 of ~574560 from 574555 documents
The effects of phorbol 12,13-diacetate on responses of guinea-pig isolated trachea to methylxanthines, isoprenaline and ryanodine
1994
1. Using guinea-pig isolated trachea, we have studied how phorbol 12,13-diacetate (PDA) modulates mechanical responses of the tissue to methylxanthines, isoprenaline and ryanodine. 2. Caffeine (10 microM-5 mM), theophylline (10 microM-5 mM) and isoprenaline (1 nM-1 microM), each inhibited the spontaneous tone of the trachea. Pretreatment with PDA (0.1-10 microM) converted relaxant responses to high concentrations of the methylxanthines into contractions. PDA produced no equivalent effect against isoprenaline. Pretreatment with verapamil (1 or 10 microM), nifedipine (0.1 microM) or incubation with Ca(2+)-free, EGTA (0.1 mM)-containing physiological salt solution (PSS) suppressed the contract…
La politique de rémunération en tant qu'incitation à la performance des dirigeants
1994
International audience; Bien que l'analyse théorique des modes de résolution des conflits entre actionnaires etdirigeants souligne le rôle de la politique de rémunération en tant qu'incitation à laperformance, celle-ci n'est pas un élément essentiel du processus d'alignement des intérêtsdes dirigeants sur les intérêts de leurs actionnaires. Les tests effectués, tant aux Etats-Unisqu'en France, montrent la faiblesse du lien entre la rémunération en espèces et laperformance. Les modes de rémunération fondés sur la performance boursière (distributiond'actions et plans d'options sur actions) ne constituent pas, pour les dirigeants, un mode derémunération adapté aux décisions stratégiques qu'ils…
Antibody synthesis in roach (Rutilus rutilus); analysis of antibody secreting cells in lymphoid organs with ELISPOT-assay
1994
The roach (Rutilus rutilus L.) which is a cyprinid fish, was immunised with bovine γ-globulin (BGG) and the antibody synthesis was studied by counting the number of specific antibody secreting cells (SASC) in the spleen and anterior kidney, and by measuring the antibody concentration in the circulation. SASCs and the total number of immunoglobulin secreting cells (TISC) were counted with the ELISPOT (enzyme-linked immunospot) assay, and anti-BGG antibodies and the concentration of immunoglobulin in sera were assayed by ELISA (enzyme-linked immunosorbent assay). The present modification of the ELISPOT-assay takes advantage of biotin-avidin amplification and yields easily detectable and nonfa…
Synthesis of .beta.-ionone in an aldehyde/xanthine oxidase/.beta.-carotene system involving free radical formation
1994
The enzymic cooxidation of β-carotene (BC) by xanthine oxidase (XO) in aqueous solutions leads to β-ionone (BI) and derivatives: epoxy-β-ionone (EPBI), dihydroactinidiolide, β-cyclocitral, pseudoionone, etc. We demonstrate, in this article, that this is due to free radical (R . ) formation during the first hour of stirring and the use of aldehydes as substrate. The bleaching of BC does not occur when the common substrate of XO, xanthine, is used; this proves that the superoxide anion O 2 .- alone is not active on BC. BI formation in this case is not observed
New descent rules for solving the linear semi-infinite programming problem
1994
The algorithm described in this paper approaches the optimal solution of a continuous semi-infinite linear programming problem through a sequence of basic feasible solutions. The descent rules that we present for the improvement step are quite different when one deals with non-degenerate or degenerate extreme points. For the non-degenerate case we use a simplex-type approach, and for the other case a search direction scheme is applied. Some numerical examples illustrating the method are given.
Derivative Fourier transform infrared spectrometric determination of ethanol in alcoholic beverages
1994
Abstract A derivative Fourier transform infrared (FT-TR) spectrometric procedure was developed for the direct determination of ethanol in alcoholic beverages, from beers to spirit samples. The method is based on first-order derivative FT-IR measurements between the peak at 1052 cm −1 and the valley at 1040 cm −1 , which are present in aqueous solutions and alcoholic beverages, by using a micro flow transmittance cell with ZnSe windows and a spacer of 0.029 mm. The method involves the accumulation of ten scans and provides accurate results in the determination of ethanol in alcoholic beverages without requiring any previous chemical treatment of the sample or a previous separation or extract…
Survival analysis of three clones of Brachionus plicatilis (Rotifera)
1994
Age-specific survival schedules of females from three genetically different clones of Brachionus plicatilis were analyzed at several environmental conditions in the laboratory.
Computertomographie der Nieren nach Tumorenukleation
1994
Two weeks to 120 months after enucleation of renal tumours the postoperative defects were correctly localized by renal computed tomography in 34 patients. Typical defect morphology was either wedge-shaped or concave. No dependence on tumour localization, tumour size, operative technique or a certain surgeon was observed. The cortical defects were smaller (mean 2.0 cm) than the original, prominent tumours (mean 3.4 cm). In small defects without tension suture of the capsule is sufficient, leading to minor defects. Larger defects were closed with a retroperitoneal or free peritoneal fat flap resulting in larger residual defects. In case of intra- or postoperative bleeding, CT could demonstrat…
Responses of Young Peach Trees to Root Confinement
1994
Rooted cuttings of Nemaguard peach [Prunus persica (L.) Batsch.] were grown in 0.18-, 0.36-, 0.90-, and 2.40-liter containers for 16 weeks to study the influence of root confinement on growth, gas exchange, water uptake, and leaf carbohydrate and nutrient content. An automatic nutrient-solution dispensing system was used to ensure uniform fertility among treatments and to prevent drought stress. Leaf area and stem length were reduced by root confinement 6 to 7 weeks after transplanting, and differences among treatments increased throughout the experiment. Final tree dry weights were reduced by 51% over a 13-fold reduction in rooting volume, but dry weight partitioning was largely unaffected…
Predictions of the public agenda from television coverage
1994
This study develops a methodology to show how German TV news in 1986 could be used to predict time trends in the public agenda for energy supply, health care, and other topics. A major influence in that year was the Chernobyl accident in the former Soviet Union. The direct result was an increase in agenda concern for energy supply. The findings showed how coverage of that incident and other issues exerted a combined influence on the public agenda.
Dynamic mechanical properties of semi-interpenetrating networks based on poly(styrene-co-maleic anhydride): 3. Poly(2,6-dimethyl-1,4-phenylene ether)…
1994
Semi-IPN's based on linear poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and diamine crosslinked poly(styrene-co-maleic anhydride) (PScoMA) copolymers containing small amounts of maleic anhydride (PSA=4.7wt.-% MA, PSB=5.8 wt-% MA) are studied with respect to the influence of cross-linking on the phase behavior. Temperature-dependent dynamic mechanical analysis (DMA) and DSC show that the semi-IPN's prepared from concentrated solution show weak crystallinity of the PPE phase. After heating above the PPE melting transition the semi-IPN's remain amorphous and the relaxation in the glass transition region as well as the terminal relaxation of the free PPE chains in the network is studied as a fu…
Metaphors of Mixed Team Play
1994
This text deals with the question of "translating women" into the configuration of team sports. In this perspective, genders are defined as social faces - embodied and numbered in various social sites/discourses. Genders are perceived as reciprocal face-rituals; through these rituals participants claim and negotiate the social faces appropriate to each sex. The approach adds face and number as relevant dimensions to the sociological analyses of gendered sport.
Many-body origin of the plasmon resonance in small metal clusters
1994
The origin of the plasmon excitation in small metal clusters is studied within the jellium model through ab initio electronic-structure calculations based on the nuclear shell model. In the limit of infinite size, the plasmon classically represents pure harmonic motion of the center of mass of the valence electrons. It is shown that this limit is already well approximated by clusters of only eight electrons.
Sesquiterpene lactones from Centaurea sphaerocephala ssp. sphaerocephala
1994
Abstract Aerial parts of Centaurea sphaerocephala ssp. sphaerocephala furnished sesquiterpene lactones commonly found in Centaurea species as well as a new germacranolide and a new elemadienolide.
Retinoid dynamics in chicken eye during pre- and postnatal development.
1994
Changes in the steady state level of retinols, retinaldehydes and retinyl esters in the trans and 11-cis forms and trans retinoic acid were measured in whole chicken eye during development from day 6 in ovo to day 3 post-hatch. These retinoids, quantified by different HPLC systems, were detected in this time sequence: trans-retinol and trans-retinyl esters in the first week in ovo, 11-cis-retinol in the second week. The highest level of 11-cis-retinaldehyde and 11-cis-retinyl esters was reached at the end of development in ovo; however, their levels increased further after hatching. The retinoic acid level decreased at the end of the first week, rising again at the end of the second week. T…
Contribution to the study of the alteration of lipase activity ofCandida rugosa by ions and buffers
1994
A semipurified C. rugosa lipase (LS) has been prepared from commercial lipase (LC) using an economical procedure. The presence of sugars and glycopeptides has been detected in LS and LC. Pure lipase only has covalently bonded sugars. The hydrolysis of olive oil catalyzed by LS and commercial lipase (LC) is sensitive to the presence of cations Na(I), Mg(II), Ca(II), and Ba(II) and to the nature of buffer. Highest enzyme activity is obtained with 0.1M Tris/HCl buffers and the combination of NaCl 0.11M and CaCl2 0.11M. Fluorescence spectroscopy analysis of LC, LS, and both pure isoenzymes lipases A and B, was used to analyze the interaction of the lipase with these effectors. Inorganic cations…
The hidden group structure of Quantum Groups:strong duality,rigidity and preferred deformations
1994
International audience
Comparison of α-acetolactate synthase and α-acetolactate decarboxylase in Lactococcus spp. and Leuconostoc spp.
1994
Cell-free extracts of Leuconostoc and Lactococcus species were tested for their alpha-acetolactate synthase and alpha-acetolactate decarboxylase activities. In Leuconostoc mesenteroides subsp. cremoris, Leuconostoc mesenteroides subsp. mesenteroides and Leuconostoc lactis, the Km of alpha-acetolactate synthase for pyruvate was close to 10 mM whereas it was 30 mM in Lactococcus lactis subsp. lactis biovar. diacetylactis. The Km of alpha-acetolactate decarboxylase for alpha-acetolactic acid was very low (0.3 mM) in Leuconostoc species in comparison to Lactococcus lactis subsp. lactis biovar. diacetylactis (60 mM). In the latter bacterium, alpha-acetolactate decarboxylase showed a sigmoidal de…
Electromagnetic excitation of the two-phonon giant dipole resonance
1994
Abstract The nuclear response of 136 Xe and 208 Pb to electromagnetic excitation was studied in peripheral, near-relativistic heavy-ion collisions. Large cross sections were observed for the one-phonon and two-phonon isovector giant dipole resonance. The results, in particular the unexpectedly large strength found for the double giant dipole resonance, are discussed and compared to that of other recent measurements.
Comparison of growth, acidification and productivity of pure and mixed cultures of Streptococcus salivarius subsp. thermophilus 404 and Lactobacillus…
1994
International audience; Pure and mixed controlled-pH batch cultures of Streptococcus salivarius subsp. thermophilus 404 and Lactobacillus delbrueckii subsp. bulgaricus 398 have been conducted. The characteristics of growth and acidification and the productivity of the cultures were compared. During the mixed cultures, the growth characteristics revealed a pronounced stimulation of S. thermophilus whereas L. bulgaricus metabolism was not significantly improved. The final total population was 1.4 to 4.9 higher than in pure cultures. The acidification characteristics were not enhanced by the mixed culture conditions. The productivity of mixed cultures was 1.7 to 2.4 times higher as compared to…
Communication Deviances and Clarity Among the Mothers of Normally Achieving and Learning-Disabled Boys.
1994
The main purpose of the study was to reexamine the association between maternal communication deviances and learning disabilities in children. In this study, we adapted and extended the procedure used by Ditton, Green, and Singer (1987). A two-part experimental task was used: one in which the child could not request any clarification of mother's instructions, and another in which the mother and child could communicate. Both communication deviances and the clarity of mothers' communication were analyzed. The subjects were 60 mother-child pairs in which half of the children had learning disabilities and the other half were normally achieving children matched for age and parents' SES. The dyad…
Bayesian prediction inM/M/1 queues
1994
Simple queues with Poisson input and exponential service times are considered to illustrate how well-suited Bayesian methods are used to handle the common inferential aims that appear when dealing with queue problems. The emphasis will mainly be placed on prediction; in particular, we study the predictive distribution of usual measures of effectiveness in anM/M/1 queue system, such as the number of customers in the queue and in the system, the waiting time in the queue and in the system, the length of an idle period and the length of a busy period.
Wetting in fluid systems. Wetting and capillary condensation of lattice gases in thin film geometry
1994
Monte Carlo studies of lattice gas models with attractive interactions between nearest neighbors on a simple cubic lattice are carried out for a L×L×D geometry with two hard walls of size L×L and periodic boundary conditions parallel to the wall. Two types of short-range forces at the walls are considered: (i) Both walls are of the same type and exert an attractive force of the same strength (in Ising model terminology, surface fields HD = H1 occur). (ii) The walls differ, one attracts and the other repels particles, again with the same strength (HD = −H1). In the first case, capillary condensation occurs at a chemical potential differing from its value for phase coexistence in the bulk, an…
SELF SIMILARITY IN SWELLING SYSTEMS: FRACTAL PROPERTIES OF PEAT
1994
Sphagnum peat gives an example of a swelling system with a self-similar structure in sufficiently wide range of scales. The surface fractal dimension, dfs, has been calculated by means of thermodynamic method on the basis of water adsorption and capillary equilibrium measurements. This method makes possible the exploration of the self-similarity in the scale range over at least 4 decimal orders of magnitude from 1 nm to 10 μm. In a sample explored, two ranges of fractality have been observed: dfs ≈ 2.55 in the range 1.5–80 nm and dfs ≈ 2.42 in the range 0.25–9 µm.
Interpleurale Katheteranalgesie
1994
Interpleural analgesia is a method of postoperative analgesia that was developed by Kvalheim and Reiestad in 1984. The main indication is postoperative pain after unilateral thoracic and upper abdominal surgery. Many authors report good analgesic effects and better postoperative lung function following cholecystectomy. There is some controversy on the effectiveness of this method after thoracic surgery. Further indications are post-traumatic pain after multiple rib fractures and chronic pain in the upper abdomen (carcinoma of the pancreas, chronic pancreatitis). The local anaesthetic of choice is bupivacaine (in concentrations of 0.25-0.75%, injection volumes of 10-40 ml, with or without ep…
High-frequency rotational ablation following failed percutaneous transluminal coronary angioplasty.
1994
Percutaneous transluminal coronary angioplasty (PTCA) failed in 29 of 1,150 patients (2.5%) after successful passage of the guide wire. The reasons for failure were inability to pass the lesion with a balloon in 28 patients and inability to dilate the lesion in 1 patient. In these patients (15 stenoses and 14 chronic occlusions) rotational ablation was performed. We were able to pass the burr through the lesion in all of them, resulting in a reduction of diameter stenosis from 87 +/- 15 to 51 +/- 18%. Rotational ablation alone was initially successful (stenoses reduction > 20% and residual stenoses < 50%) in 15 of 29 (52%) patients. Additional PTCA was performed in 21 of 29 (72%) patients, …
Polymer chains confined into tubes with attractive walls: A Monte Carlo simulation
1994
A bead-spring off-lattice model of a polymer chain with repulsive interactions among repeating units confined into straight tubes of various cross sections, DT2, is studied by Monte Carlo simulation. We are also varying the chain length from N = 16 to 128 and the strength of a short-range attractive interaction between the repeating units and the walls of the tube. Longitudinal and perpendicular static linear dimensions of the chains are analyzed, as well as the density profile of repeating units across the tube. These data are interpreted in terms of scaling concepts describing the crossover between three-dimensional and quasi-one-dimensional chain conformations and the adsorption transiti…
Adverse effects associated with the short-term treatment of panic disorder with imipramine, alprazolam or placebo
1994
Summary Side effects play a significant role in the selection of drugs to be used in panic disorder/agoraphobia whose polyphobic symptomatology often includes a suspiciousness about taking drugs and a fear of undesired side effects which may lead to the refusal of treatment. The safety, side effects and patients' acceptance of alprazolam and imipramine versus placebo were evaluated in 1168 subjects with panic disorder/agoraphobia who had been enrolled in the second phase of the Upjohn World Wide Panic Study. Side effects that worsened over baseline to a greater extent with alprazolam than with imipramine and placebo were sedation, fatigue/weakness, memory problems, ataxia and slurred speech…
Occurrence of Fibrous Sepiolite in Alkaline Basalt in the Valley of Alfara (Baix Ebre, Tarragona, Spain)
1994
Quasi-resonant energy transfer in collisions: Na2(A1? u + )+K(4S)
1994
Cross sections for electron energy transfer from the initial rotational stateJ′of the two lowest vibrational levelsv′=0 andv′=1 of excited dimers Na2(A) to potassium atoms as described by Na2(A1Σu+,v′J′)+K(4S)→Na2 (X1Σg+,v″J″)+K(4P)+ΔE have been examined by laser-induced fluorescence. A strong increase of the cross section by as much as an order of magnitude has been observed for those dimerv′J′-levels for which the dipole transitions are close to resonance of the 4S-4P transitions in the atom (ΔE<4 cm−1). The absolute cross sections for energy transfer have been calculated by the Rabitz approximation of first-order perturbation theory. In the case of closest energy resonance (ΔE=0.9 cm−1) …
A new method to measure the size distribution of insoluble submicron particles in water
1994
Abstract In the atmosphere, cloud and fog droplets usually contain insoluble material. The role of these insoluble particles is still unknown today, and is of interest to study. To determine the size distribution and number concentration of these particles in water, different techniques are available. The instrumentation, however, to measure nanometer-sized particles down to 50 nm diameter is not known. A new instrument, the Liquid Tandem Differential Mobility Analyser (LTDMA), was developed to measure size distributions of insoluble particles in water in the size range 50–300 nm in diameter. The new method is based on nebulising, e.g. cloud water and forming a residue aerosol consisting of…
Electrophilic substitution and cyclization of 2,2′-bis(N-methylindolyl): A simple access to potential protein kinase C inhibitor
1994
A strategy is described for the synthesis of functionalized and cyclized 2,2′-bisindolyl derivatives related to several basic systems of natural products. The starting 2,2′-bis(N-methylindolyl) (8) reacts with a variety of electrophiles and electrophilic dienophiles to furnish the novel, functionalized and cyclized bisindolyl derivatives 9–16. In addition, some reactivity and structural aspects are discussed; an X-ray crystallographic analysis of the 2,2′-bisindolyl 8 provided valuable information for the conformational analyses.
Synthesis and Spectroscopic Characterisation ofbis-Complexes of Cobalt(II), Nickel(II) and Copper(II) with N,N,N′N′-Tetraethylpyridinecarboxamide
1994
Abstract Bis-complexes of Co(II), Ni(II) and Cu(II) with tedpa (N,N,N′N′-tetraethyl-pyridinedicarboxamide) having the general formula [M(tedpa)2]X2 (X = ClO4, PF6) have been synthesized and characterised by i.r., electronic and e.p.r. spectra. The spectroscopic results suggest that the tedpa acts in these compounds as tridentate ligand through two oxygen atoms and a nitrogen (from the pyridine ring) atom. A distorted octahedral environment (MN2O4 chromophores) for the metal atoms is inferred from the spectroscopic data.
Effect of Hormones on Sucrose Uptake and on ATPase Activity of Citrus sinensis L. Osbeck Leaves
1994
Carbohydrate accumulation in young, fully expanded leaves of Citrus sinensis L. Osbeck is affected by the presence of the fruitlet on the shoot. Previous work gave evidence that gibberellins may be involved in this 'fruit effect'. In the present work we have studied the effect of gibberellic acid (GA3) on 14C-sucrose uptake by leaf discs and whether its action could be due to a modulation of the plasma membrane ATPase, which maintains the H+ gradient that drives H+/sucrose co-transport. The effect of GA3 on 14C-sucrose uptake depended on the osmolarity of the assay medium. At 300 mOsm a reduction in the uptake rate was observed. The inhibitory effect of the hormone disappeared after preincu…
Two tyrosinase nonapeptides recognized on HLA-A2 melanomas by autologous cytolytic T lymphocytes
1994
A number of cytolytic T lymphocyte (CTL) clones derived from several melanoma patients have been found to recognize a majority of melanomas from HLA-A2 patients. We have reported previously that two such CTL clones recognize a product of the tyrosinase gene that is presented by HLA-A2. Here we show that one of these CTL clones recognizes a peptide encoded by the first nine amino acids of the putative signal sequence of tyrosinase. The other CTL clone recognizes a different tyrosinase peptide corresponding to amino acids 368-376. Both peptides contain consensus motifs of HLA-A2 binding peptides.
Improved nitrogen metabolism in rats fed on lipid-rich liquid diets
1994
N metabolism was studied in young rats fed on lipid-rich, isonitrogenous, purified liquid diets, a convenient and easy technique for inducing voluntary overfeeding of energy and lipids under controlled nutritional conditions. Overfed rats showed a marked N retention at the expense of a reduced production of urea. The capacities of isolated hepatocytes to synthesize urea and glucose from added precursors were greatly diminished. The activities of the urea cycle enzymes and several enzymes involved in the availability of NH3, for this pathway were concomitantly reduced in overfed animals. Therefore, our results showed an improved N metabolism in overfed rats promoted by the overfeeding of lip…