showing 36 of ~574560 from 574555 documents
A unified approach to projective lattice geometries
1992
The interest in pursuing projective geometry on modules has led to several lattice theoretic generalizations of the classical synthetic concept of projective geometry on vector spaces.
Oxidized respiratory molecules induced in vivo by nitrite in Pontodrilus littoralis (oligochaeta)
1992
Abstract 1. The in vivo effect of nitrite has been investigated in Pontodrilus littoralis. 2. Exposure of the animals at nitrite concentrations (0.05–0.1%) produced methaemoglobin and hemichromes. 3. Disappearance of oxidized forms was obtained when normal rearing conditions were restored. 4. Longer exposure to higher nitrite concentrations produced irreversible oxidized forms.
Color Doppler Imaging of the Ocular Ischemic Syndrome
1992
Purpose: This study describes hemodynamic characteristics of the ophthalmic, central retinal, and posterior ciliary arteries in 16 eyes of 11 patients with the ocular ischemic syndrome. Understanding the hemodynamic characteristics of the retrobulbar circulation may elucidate the natural history and pathophysiology of the ocular ischemic syndrome and perhaps form the basis for rational treatment of this condition. Methods: Color Doppler imaging, a procedure that permits rapid noninvasive imaging of the ophthalmic, central retinal, and posterior ciliary arteries, was used to quantitate peak systolic blood flow velocities and vascular resistance (pulsatility index) within these vessels in stu…
Adjustment costs, uncertainty, and the theory of investment: the case of non-renewable natural resources
1992
Abstract This paper examines the effects of mineral price and extraction cost uncertainty on the investment program of a competitive resource-extracting industry that faces convex costs of adjustment. The results show that depletion of mineral reserves will slow down if the marginal adjustment cost function is concave or linear, whereas the effect will be ambiguous if the function is convex.
Effects of gamma interferon on a B16 melanoma cell line and its doxorubicin-resistant variant.
1992
Flow cytometric DNA analysis of hepatic tumours on ultrasound-guided fine-needle aspirates
1992
A study was performed on a nonconsecutive series of 51 patients in order to assess the feasibility, reliability, and usefulness of flow cytometric (FCM) DNA analysis of samples obtained from benign and malignant hepatic tumours by means of ultrasound-guided fine-needle aspiration (UG-FNA). Cytological and often histological confirmation of the nature of the lesion was obtained in all cases from an expert pathologist. For FCM DNA analysis in 32 cases, it was also possible to use samples obtained at surgery from the actual tumours. There were no post UG-FNA complications, either early or late. It was possible to perform FCM DNA analysis on 6/7 (85.7%) of the benign tumour aspirates and all 44…
Induction of the peroxisome proliferator activated receptor by fenofibrate in rat liver
1992
AbstractThe process of peroxisome proliferation in rodent liver by hypolipidemic compounds and related substances has recently been shown to be receptor-madiated. In the present study, we have examined the effect of oral administration of the strong peroxisome proliferator fenofibrate on the hepatic expression level of the peroxisome proliferator activated receptor (PPAR) in rats. Immunoblots of rat liver cytosols and nuclear extracs using antibodies raised against recombinant PPAR/β-galactosidase fusion proteins revealed a pronounced increase in the amount of PPAR protein in response to fenofibrate treatment. This induction could also be confirmed at the level or RNA by Northern blotting. …
Large-Eddy Simulation of Turbulent Flow and Heat Transfer in Plane and Rib-Roughened Channels
1992
Large-eddy simulation results are presented and discussed for turbulent flow and heat transfer in a plane channel with and without transverse square ribs on one of the walls. They were obtained with the finite-difference code Harwell-FLOW3D, Release 2, by using the PISOC pressure-velocity coupling algorithm, central differencing in space, and Crank-Nicolson time stepping. A simple Smagorinsky model, with van Driest damping near the walls, was implemented to model subgrid scale effects. Periodic boundary conditions were imposed in the streamwise and spanwise directions. The Reynolds number based on hydraulic diameter (twice the channel height) ranged from 10 000 to 40 000. Results are compar…
MITOCHONDRIAL DISORDER SECONDARY TO INFLAMMATION IN POLYMYOSITIS - 2 CASES
1992
National audience; Abstract: Two cases of polymyositis were followed using phosphorus nuclear magnetic resonance spectroscopy. The spectra recorded during remission were normal, but those collected from the gastrocnemius muscle during the active phase of the diseases showed an increased inorganic phosphate level or a decreased phosphocreatine content. The intracellular pH was normal. These findings may be related to an impairment in mitochondrial metabolism secondary to the inflammatory process. Moreover, the fact that the abnormalities observed disappeared after treatment suggests that phosphorus NMR spectroscopy could be used as a non-invasive method in the follow-up of polymyositis, but …
<title>Ultrasound detection of cavitation as a phenomenon common to intervention devices causing tissue ablation</title>
1992
Cavitation previously has been observed in association with ultrasonic angioplasty and high- frequency rotational atherectomy. This study evaluates the production of cavitation accompanying the use of several catheter-based devices under development or in current use in the practice of interventional cardiology. Catheters were examined in an in vitro model, and cavitation was evaluated using standard ultrasound imaging equipment. Cavitation was detected with each of the devices that effects tissue ablation, but not tissue resection. Devices produced characteristic patterns of cavitation dependent on the mode of energy release of the device. The size, but not the intensity, of the cavitation…
Selective chiral inhibition of Ca2+ entry promoted by bisbenzyltetrahydroisoquinolines in rat uterus.
1992
Abstract The effects of diltiazem and six bisbenzyltetrahydroisoquinoline alkaloids (antioquine, 7-O-methylantioquine, dimethylantioquine, monterine, granjine and cordobimine) were studied in rat isolated uterus in order to clarify the mechanisms of their relaxant actions. All the compounds tested completely relaxed KCl-induced contractions and totally or partially inhibited oxytocin-induced rhythmic contractions. Only alkaloids with absolute configurations (1R,1′S or 1R,1′R) acted intracellularly, promoting relaxation of contractile responses induced by oxytocin in a Ca2+-free medium, as does papaverine. Alkaloids of the antioquine series (1S,1′R) selectively inhibited Ca2+ entry. The grea…
Morphological, immunohistochemical and biochemical characterization of 6 newly established human ovarian carcinoma cell lines
1992
Six permanent human tumor cell lines (OV-MZ-1 to 6) were established from 6 patients with serous adenocarcinomas of the ovary. These cell lines were derived from both solid tumors and ascites, from pre-treated and untreated patients, and are available over a range of in vitro passage numbers. The tumor cells grow its monolayers and develop foci of “piled-up” cells in confluent cultures. Flow cytophotometry showed that all the lines exhibited DNA hyperdiploidy with DNA tetraploidy in one cell line and DNA aneuploidy in the other cell lines. The mean population doubling time ranged from 24 to 52 hr. Transmission electron microscopy demonstrated that the tumor cells of all cell lines exhibited…
Study of accelerated carbofuran biodegradation in some French soils
1992
EPR Study of Manganese-Doped PLZT-8/65/35 Ceramics
1992
Shallow-donor impurities in indium selenide investigated by means of far-infrared spectroscopy.
1992
Shallow impurities in n-type indium selenide (InSe) have been investigated by means of Fourier-transform spectroscopy in the far-infrared region. Three electric dipole transitions have been identified: 1s-2${\mathit{p}}_{\ifmmode\pm\else\textpm\fi{}}$, 1s-2${\mathit{p}}_{0}$, and 1s-3${\mathit{p}}_{\ifmmode\pm\else\textpm\fi{}}$, corresponding to electrons bound to native donors and tin-, silicon-, and chlorine-related donors, whose ionization energies (17.6, 18.1, 18.8, and 19 meV, respectively) have been determined through the Guerlach-Pollmann model. That model was also used to calculate the oscillator strengths of those dipole transitions, and then to estimate the shallow-donor concentr…
Regulation of glutathione metabolism in Ehrlich ascites tumour cells.
1992
Glutathione metabolism was studied in cancer cells during the growth of an Ehrlich ascites tumour. GSH, but not GSSG, content decreases when cell proliferation and the rate of protein synthesis in the tumour decrease. This change correlates with a decrease in the rate of GSH synthesis and an increase in glutathione peroxidase and glutathione S-transferase activities. Glutathione efflux from tumour cells seems to co-ordinate with the rate of GSH synthesis. Cysteine, and not methionine, promotes GSH synthesis in tumour cells. However, changes in the rate of GSH synthesis are not due to limitations in the supply of blood cysteine or to changes in the intracellular amino acid pool of the cancer…
Shift-and-scale-invariant pattern recognition using an elliptic coordinate-transformed phase-only filter
1992
A shift-and-scale-invariant elliptic coordinate-transformed phase-only filter in proposed. The filter is built in three steps: the complex conjugate of a basic-size target spectrum is calculated, its phase-only part is taken, and then the elliptic coordinate transformation is made. In the extreme case the scale ratio of recognizable objects equals 1:1.5, permitting good recognition of object sizes S within the range 0.83/= S/= 1.25. Discrimination abilities and relative Horner efficiencies of a few versions of the filter are calculated.
White-light Fourier transformer with low chromatic aberration.
1992
A simple Fourier transformation system working with broadband parallel illumination is presented. The proposed setup, consisting of two on-axis zone plates and an achromatic objective, allows us to obtain the achromatic Fourier transform representation of the input at a finite distance with a low chromatic aberration. The discussion of the system, using the Fresnel diffraction theory, leads to an analytical expression to evaluate the transversal and longitudinal chromatic aberrations. It is shown that the resulting chromatic aberrations for typical values of the involved parameters are less than 1% over the entire visible spectrum.
Intravascular ultrasound imaging of arterial wall architecture.
1992
Intravascular ultrasound (IVUS) is a promising new technique for assessing vascular morphology and structure. Controversy exists whether the three-layer appearance of the arterial wall correctly reflects the histologic structures of the intima, media, and adventitia. We performed an experimental study to clarify the three-layer appearance. The vessel wall architecture was analyzed by IVUS on eight different kinds of plastic cylinders, 24 normal blood vessels from pigs, and 59 human arterial segments. A distinct three-layer appearance was observed on all the plastic cylinders when the ultrasound beam was perpendicular to the wall. A three-layer appearance was also seen in the arterial wall, …
Association of AUUUA-binding Protein with A + U-rich mRNA during nucleo-cytoplasmic transport
1992
Resealed nuclear envelope (NE) vesicles from rat liver containing entrapped exogenous RNA were used to study the effect of adenosine+uridine binding factor (AUBF), present in cytosolic cell extracts, on ATP-dependent transport of A+U-rich RNA (AU+RNA) and A+U-free RNA (AU-RNA) across the NE. This factor specifically binds to A+U-rich sequences present in the 3' untranslated regions of lymphokine and cytokine mRNAs, containing overlapping AUUUA boxes (granulocyte-macrophage colony stimulating factor, interleukin-3). Addition of AUBF to the extravesicular compartment markedly increased the efflux of the in vitro transcribed, capped and polyadenylated AU+ RNAs. Export of entrapped AU- control …
The precocious commitment of wing Anlagen in Tenebrio molitor revealed by the addition of 20-hydroxyecdysone.
1992
Abstract An injection of 20-hydroxyecdysone (10 μg per animal) 6–13 days after the moult of the last larval instar of Tenebrio molitor induces the development of prothetelic larvae and larval-pupal intermediates. The state of larval-pupal switchover, or commitment, is only disclosed at the time of injection of the moulting hormone. Prothetelic A and B larvae, with small and medium sized wing Anlagen, undergo another larval or pupal instar. Prothetelic C larvae with bigger Anlagen are unable to moult, but the adult programme is expressed. Ecdysed larval-pupal intermediates give more or less perfect adults, while unecdysed mealworms, imprisoned in their larval cuticle, also expressed the adul…
Immobilization of reagents by polymeric materials. Determination of metamizol
1992
Abstract A method for immobilization of inorganic reagents, based on the dispersion of the reagent into an unsaturated polyester solution is applied to immobilization of lead dioxide. The obtained solid is of application in a flow-injection manifold for indirect atomic absorption determination of metamizol in pharmaceutical formulations. The procedure gives a linear calibration graph up to 6 ppm of metamizol with a relative standard deviation of 1.6% (3.0 mg/l) and a sample throughput of 72 hr−1.
Geoid effects in a convecting system with lateral viscosity variations
1992
The geoid signal and the flow patterns of two-dimensional steady state convection models with exponential temperature- and depth dependent viscosity are compared with results for an equivalent stratified viscosity structure. In analogy to Richards and Hager [1989], the latter are computed by a “dynamic response” approach. The flow fields obtained with this approach are quite different from the full solution; the geoid signals are similar but the amplitudes differ significantly. The differences are analysed in the horizontal wavenumber domain and in the spatial domain. They may lead to an overestimation of the viscosity contrast of the earth's mantle derived by modeling the earth's geoid wit…
Problems in time-intensity measurements. A case study-Bitterness evaluation in water solutions and in beers
1992
International audience
Acute toxicity of toluene, hexane, xylene, and benzene to the rotifers Brachionus calyciflorus and Brachionus plicatilis.
1992
A large number of studies on the biological effects of oil pollution in the aquatic environment deal with the effects of whole crude or refined oils or their water-soluble fractions. However, low boiling, aromatic hydrocarbons, which are probably the most toxic constituents of oil, have until now not been examined in sufficient detail. Toluene, benzene and xylene, constitute a major component of various oils. They may be readily lost by weathering but are toxic in waters that are relatively stagnant and are chronically polluted. Korn et al. have stated that toluene is more toxic than many other hydrocarbons such as benzene, though the latter are more water-soluble. Report of the effects of …
Zero axial irradiance by annular screens with angular variation
1992
For optical alignment, it may be convenient to use a three-dimensional diffraction pattern with zero irradiance along the optical axis. This pattern is created here by using annular screens in the form of a phase daisy, a daisy flower, or a pie, with an even number of slices of an equal central angle and with every other slice with a phase retardation of 180 degrees . We recognize this form of angular variation as a particular solution of a wider set of functions that are able to produce zero axial irradiance.
Ethique professionnelle et régulation économique du marché des soins ambulatoires : de la théorie des contrats à l'économie des conventions
1992
What is the part played by professionnal ethics in the economic regulation of the market for ambulatory care (heterogeneity, uncertainty, information asymmetry...) and extrinsic rigidities (imposed by medical corporation and public authorities) ? Is it the internal control variable from "interested" self-regulation that implicitly relies on teological conception of ethics ? Or, the essential being of conventions for "quality" and "activity" that, through the cycle of gift economics, set upspontaneous order, with respect to professional ethics ? What usecan we do with such theoritical approach for the understanding andthe trend of politics in ambulatory care ?
Model-Based Decision Support System for Individual Prescription of the Dialysate Bicarbonate Concentration in Hemodialysis
1992
A decision support system has been developed that determines the optimal dialysate bicarbonate concentration in hemodialysis therapy for each patient individually. The knowledge about the behavior of the acid-base state during treatment has been provided by a mathematical model for the description of dynamic exchange processes during hemodialysis. This model simulates the sodium and water distribution, the acid-base state as well as the ventilation. The decision support system uses the model for the prediction of the end-dialysis acid-base state and calculates by means of linear optimization the dialysate bicarbonate concentration which is necessary to reach a specified end-dialysis state.…
Regression of structural vascular changes in hypertensives after captopril treatment.
1992
In order to investigate whether hypertension-related structural vascular changes may be influenced by antihypertensive treatment, 10 patients were studied suffering from essential arterial hypertension, five males and five females, aged between 34 and 61 years (mean age: 46.9 +/- 8.13 years). All patients received a placebo for 1 week and then captopril, 75 mg b.i.d. for 3 months. After placebo and captopril treatments, the following parameters were evaluated: SBP, DBP, mean blood pressure (MBP), by the formula 1/3 (SBP + 2 x DBP) and basal and minimal vascular resistances, respectively obtained by the ratios MBP/rest flow and MBP/peak flow. Blood flows have been obtained by strain gauge pl…
Photon yields and decay times of cross luminescence in ionic crystals
1992
The authors report on the scintillation properties of the ternary inorganic crystals KMgF/sub 3/, KYF/sub 4/:Rb, K/sub 2/YF/sub 5/, KLuF/sub 4/, RbMgF/sub 3/, KZnF/sub 3/, BaTm/sub 2/F/sub 8/, LiYF/sub 4/:Nd, and BaF/sub 2/:Rb. The scintillation light output of these crystals was estimated from the X-ray-induced emission spectra. Optical absorption spectra and decay time spectra were also measured and are presented. The first four crystals produced cross-luminescence (CL) with a decay time of about 1.5 ns. CL was not observed for the other crystals. >
Multifocal aplasia cutis congenita, distal limb hemimelia, and cutis marmorata telangiectatica in a patient with Adams-Oliver syndrome.
1992
Summary We describe an 18-month-old boy with multifocal scalp defects over the posterior parietal region combined with an underlying defect of the skull, left lower limb distal hemimelia and generalized cutis marmorata telangiectatica, consistent with a diagnosis of Adams–Oliver syndrome (aplasia cutis congenita with distal transverse limb defects).
Abelian charges in a nonabelian Yang-Mills theory from the stratification of the space of gauge potentials
1992
Abstract The Abelian charges in a non-Abelian Yang-Mills-Dirac theory arising from the reduction of the structure group are studied. They are defined by the concept of the stabilizer gauge transformations. Their properties are investigated. The relationship between the whole class of stabilizers and the stratification of the space of gauge potentials is given. The effect of the spontaneous symmetry breaking mechanism on these charges is discussed.
Synthesis of pyrido[2,3-d]pyrimidines in the reaction of 6-amino-2,3-dihydro-2-thioxo-4(1H)-pyrimidinone with chalcones
1992
6-Amino-2,3-dihydro-2-thioxo-4(1H)-pyrimidinone (1) reacts in boiling DMF with α,/β-unsaturated ketones 2 yielding the pyrido[2,3-d]pyrimidine systems 5 and 6, respectively. The orientation in the addition process can be determined by nmr measurements, especially by NOE difference spectroscopy. The products do not correspond to a normal Skraup or Doebner-v. Miller synthesis.
CPF : Continuous polymer fractionation
1992
A method is presented by means of which it is possible to fractionate polymers according to their solubility on a technical scale. The CPF consists of a continuous counter-current extraction process in which a homogeneous mixture of a molecularly or/and chemically non-uniform high molecular weight product is divided into two portions of considerably lower non-uniformity. The principle of the CPF is described in general terms and examples are given for the fractionation of homopolymers.
Polycondensed nitrogen heterocycles. Part24. Pyrrolo[3,4-c]isoquinolinone by thermal rearrangement of a pyrrolylbenzotriazinone
1992
Rearrangement under acidic conditions of the pyrrolylbenzotriazinone 7 afforded the pyrrolylbenzamides 10 and 11. By thermal rearrangement instead, the first fully aromatic derivative of the pyrrolo[3,4-c]isoquinoline ring system 9 was obtained.
Spin, moments, and mean square nuclear charge radius ofSr77
1992
The neutron deficient $^{77}\mathrm{Sr}$ nucleus was studied by fast ion beam collinear laser spectroscopy with a detection scheme based on optical pumping, state selective neutralization, and atom counting. From the measured hyperfine splitting and isotope shift of the Sr II transition 5s $^{2}$${\mathit{S}}_{1/2}$\ensuremath{\rightarrow}5p $^{2}$${\mathit{P}}_{3/2}$ the nuclear spin I=5/2, the nuclear moments \ensuremath{\mu}=-0.348(4)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$, ${\mathit{Q}}_{\mathit{s}}$=1.40(11) b, and the change in mean square charge radius \ensuremath{\delta}〈${\mathit{r}}^{2}$${\mathrm{〉}}^{88,77}$=0.248(12) ${\mathrm{fm}}^{2}$ were deduced. These ground-state proper…