showing 36 of ~574560 from 574555 documents
Letter on the election of Ernesto Foldats as a member of The Linnean Society of London
1993
Letter on the election of Ernesto Foldats as a member of The Linnean Society of London, stating that, subject to the conditions, Ernesto Foldat must attend a meeting of the society for official admission within six months of the election, but an extension is possible. A member is not entitled to vote at any meeting of the Society until an official admission has taken place. Letter on 1 page, signature of the executive secretary of the society at the bottom. Stored in the Museum of the University of Latvia Botanical and Mycological collections.
QCD matching conditions at thresholds
1993
The use of MS-like renormalization schemes in QCD requires an implementation of nontrivial matching conditions across thresholds, a fact often overlooked in the literature. We shortly review the use of these matching conditions in QCD and check explicitly that the prediction for $\alpha_s(M_Z)$, obtained by running the strong coupling constant from the $M_\tau$ scale, does not substantially depend on the exact value of the matching point chosen in crossing the $b$-quark threshold when the appropriate matching conditions are taken into account.
Les autorités consulaires qui doivent protection et assistance à leurs ressortissants n'ont pas l'obligation de les représenter en justice
1993
International audience
Quantum effects on the herringbone ordering ofN2on graphite
1993
The effects of quantum fluctuations on the ``2-in'' herringbone ordering in a realistic model of 900 ${\mathrm{N}}_{2}$ molecules adsorbed in the (\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{} structure on graphite are studied via path-integral Monte Carlo (PIMC) simulations. Quasiclassical and quasiharmonic calculations agree for high and low temperatures, respectively, but only PIMC gives satisfactory results over the entire temperature range. We can quantify the lowering of the transition temperature and the depression of the ground state order to 10% as compared to classical modeling.
Color Doppler ultrasonography of the eye and orbit
1993
Color Doppler imaging is the recent development in ultrasonography that allows simultaneous two-dimensional structural imaging in Doppler evaluation of blood flow. With this technique, it is possible for the first time to indirectly display the fine orbital vessels such as the ophthalmic artery and its branches, the central retinal artery, the posterior ciliary artery, and the lacrimal artery. Also, the display of venous structures such as the superior ophthalmic vein, the vortex vein, and the central retinal vein is possible. In addition to the qualitative display of those vessels, the hemodynamics in those vessels can be quantitatively assessed by looking at the Doppler spectrum and deter…
Influence of ventral tegmental area (A10 region) on flight behaviour elicited by hypothalamic stimulation in the cat.
1993
The influence of the ventral tegmental area (VTA) (dopaminergic A10 group neurons) on flight behaviour, induced by hypothalamic stimulation, was studied in the cat. Co-stimulation of hypothalamus and VTA (ipsi- or contralateral) induced an increase of the flight latency. Slow-motion analysis of flight behaviour showed that this increase was due to the augmentation of the fixation latency (FL) whereas the upright latency (UL) was not modified. Sulpiride injection (50 mg/kg i.p.) provoked the disappearance of VTA effect without affecting the basal behavioural sequence. The results show that DA A10 group neurons increase the attentive component of the flight reaction, suggesting a possible inf…
Studies on the diurnal courses of the contents of abscisic acid, 1-aminocyclopropane carboxylic acid and its malonyl conjugate in needles of damaged …
1993
Summary The diurnal courses of the contents of 1-aminocyclopropane carboxylic acid (ACC), its malonyl conjugate (MACC) and abscisic acid (ABA) in the two-year-old needles of damaged and undamaged spruce trees (Picea abies L.) were investigated. The contents of ACC and MACC were significantly higher in the needles of the damaged trees as compared with the undamaged ones. In the needles of the damaged spruce trees, the ACC and MACC contents, and ABA contents as well, fluctuated to a greater extent than those in the undamaged spruce trees during the day. The relationships between ACC-ABA and MACC-ACC contents as well are also discussed.
Amplifying effect of serotonin on contractile responses in rat aorta and depletion of intracellular Ca-stores
1993
1. Serotonin, 1 microM, induces a contractile response in isolated rat aorta in the presence or absence of extracellular Ca. 2. In Ca-free media, the fast phasic contraction is lower in magnitude and further addition of serotonin evokes no response. 3. Recovery of the contractile response in Ca-free medium is obtained by a 40 min incubation in Ca-containing solution. 4. In Ca, Mg-free medium, the response to serotonin is significantly higher than that obtained in the presence of Mg. 5. An amplifying effect of serotonin on the contractile responses induced by serotonin itself or by noradrenaline was observed in Ca-containing but not in Ca-free solution.
Effect of chelatants on gellan gel rheological properties and setting temperature for immobilization of living bifidobacteria.
1993
The effect of various concentrations of sequestrants (sodium citrate, sodium metaphosphate, and EDTA) was studied on gellan gel (1.5-2.5% (w/v)) setting temperature and rheological properties. Addition of EDTA between 0 and 0.8% (w/v) led to a progressive decrease of setting temperature. Citrate and metaphosphate decreased this parameter when added up to 0.4 or 0.6%, depending on gellan gum concentration, eventually resulting in the absence of gel formation at room temperature for the 1.5% gellan solution containing 0.4% citrate. This effect was accompanied by a significant decrease of gel strength and stiffness and might be attributed to the binding of the divalent cations required for cha…
SEXUALHORMONE-BINDING GLOBULINE (SHBG) AND FREE TESTOSTERONE (FTE) IN PATIENTS WITH ULLRICH TURNLR SYNDROME(UTS) RECEIVING OXANDROLONE
1993
Our investigation showed that the concentration of SHBG decreased in healthy girls and boys at increased FIE concentrations. It was therefore the aim of the present study to examine the effects of anabolic steroid oxandrolone in SHBG and FTE concentrations in patients with Turner's syndrome. The normal dose to promote growth in patients wilh UTS is 0,1 mg/kg/BW. Our patients received a very low dose of 1,25 mg oxandrolone/doy. We analysed 21 sera of UTS patients. The determination of SHBG concentrations was performed with the IRMA (Famos diagnostics, Oulunsala, Finnland), the concentration of FTE was determined with the RIA (Immunchem.Corporation, Carson, USA). In 7 untreated UIS patients w…
Universidad y formacio de recursos humanos
1993
Référence interne : 93091
A Lattice-Geometric Proof of Wedderburn’s Theorem
1993
This note presents a proof of Wedderburn’s theorem concerning the classification of semisimple rings within the conceptual frame of projective lattice geometry.
Mesadenes maturation and its hormonal control in the milkweed bug, Oncopeltus fasciatus
1993
Abstract Adult maturation of the mesadenia was examined by electron microscopy. The glandular epithelium exhibits only one cell type with a polarity along the haemocoel-lumen axis. In newly emerged males, the glands show little signs of secretory activity although the narrow lumen contains some material. Dramatic changes commence at day 2. The rER increases drastically, and at day 3 cisternae of the rER are considerably distended and include a fine granulated product. The lumen of the gland widens greatly and stores material of the same appearance as in the rER inclusions. The mode of the secretory process is not clear since membrane bound vesicles are not formed. SDS-PAGE of the secretion …
Hölder continuity of Sobolev functions and quasiconformal mappings
1993
Solid proton conductors as room-temperature gas sensors
1993
Ammonia-exchanged ceramic samples of beta alumina have been obtained from plasma-dispersed powders. The ionic conductivity is slightly affected by ion exchange, but the surface conductivity for the amonia-exchanged sample drastically changes in the presence of the water and ammonia vapours. The ammonia-doped xerogel of antimonic acid hydrate in the form of a thick film has been tested as a potentiometric ammonia sensor.
Theoretical split-window algorithms for determining the actual surface temperature
1993
Two split-window strategies for obtaining the actual surface temperature (AST) from an infra-red sensor system are investigated by means of simulations of radiometer signals for a wide range of different geophysical situations. The differences between strategies are closely related to the strong or weak presence of atmospheric effects in the split-window coefficient. It has been demonstrated that the strong presence makes it necessary to know the total atmospheric water vapour as well as the effective emissivities in the two thermal channels for applying the strong split-window method, whereas for the weak presence one only needs to know the emissivities. Simplified algorithms have been obt…
Invisible Higgs decays and neutrino physics
1993
Abstract A wide class of neutrino physics motivated models are characterized by the spontaneous violation of a global U(1) lepton number symmetry at or below the electroweak scale by an SU(2)⊗U(1) singlet vacuum expectation value 〈 σ 〉 ≲ O(1) TeV. In all these models the main Higgs decay channel is likely to be “invisible”, e.g. h → JJ, where J denotes the associated weakly interacting pseudoscalar Goldstone boson — the majoron. This leads to events with large missing energy that could be observable at LEP and affect the Higgs mass bounds obtained, as well as lead to novel ways to search for Higgs bosons and high-energy supercolliders such as the LHC/SSC.
Investigations on the content indole-3-acetic spruce needles of healthy and damaged trees of various sites
1993
Summary Surveys were made on the concentration of indole-3-acetic acid (IAA) in spruce trees of various sites. The concentrations of the hormone were specified with a radioimmunoassay after the needle extract had been purified in several steps. The content of IAA in needles of damaged trees was distinctly lower than the content in needles of healthy trees. Another feature was the annual rythm of the IAA content with the maximum of concentration in June. A distinct diurnal course with highest level of concentration during the early afternoon hours was also observed. The diurnal rhythm of the damaged trees was clearly lower. The supposition is that the lower IAA content is responsible for a p…
Purification and characterization of geranyl diphosphate synthase from Vitis vinifera L. cv Muscat de Frontignant cell cultures
1993
A geranyl diphosphate synthase (EC 2.5.1.1), which catalyzes the formation of geranyl diphosphate from dimethylallyl diphosphate and isopentenyl diphosphate, was isolated from Vitis vinifera L. cv Muscat de Frontignan cell cultures. Purification of the enzyme was achieved successively by ammonium sulfate precipitation and chromatography on DEAE-Sephacel, hydroxylapatite, Mono Q, Phenyl Superose, Superose 12, and preparative nondenaturing polyacrylamide gels. The enzyme formed only geranyl diphosphate as a product. In all cases, neither neryl diphosphate, the cis isomer, nor farnesyl diphosphate was detected. The enzyme showed a native molecular mass of 68 [plus or minus] 5 kD as determined …
Presence of a capsule in Vibrio vulnificus biotype 2 and its relationship to virulence for eels
1993
Strains of Vibrio vulnificus biotype 2, isolated from internal organs of diseased European eels as pure cultures of opaque cells, together with some reference strains from Japanese eels, were used in this study. Spontaneous translucent-phase variants were obtained from the corresponding parent strains and compared for a variety of phenotypic traits related to virulence for eels. The rate of colony dissociation from opaque to translucent cells was higher (around 10(-2)) than that observed for translucent to opaque cells (10(-3) to 10(-4)). Electron microscopy with ruthenium red revealed the presence of a capsule of variable thickness on opaque cells, whereas translucent-type colonies had no …
A SCAN-SADS comparison study of psychotic subjects and their first-degree relatives
1993
Two diagnostic interviews, the Schedule for Affective Disorders and Schizophrenia (lifetime version) (SADS-LA) and the Schedule for the Clinical Assessment of Neuropsychiatry (SCAN) were compared for main diagnoses and for their acceptibility to psychotic subjects and their psychiatrically well relatives. Broad agreement for DSM-III, DSM-III-R and draft ICD-10 diagnoses was good, although there were areas of disagreement between the two interviews which are discussed.
1H,13C,17O and19F NMR spectroscopic study of isomeric ring-substituted monofluoro-(E)-3-phenylpropenals
1993
Isomeric ring substituted monofluoro-(E)-3-phenylpropenals (cinnamaldehydes) were synthesized in order to provide, with the NMR-active 19F nucleus, an insight into the influence of substituents and the transmission of electronic effects between the aromatic ring and the side-chain. Their 1H, 13C and 17O NMR chemical shifts and their nJ(H,H), nJ(H,F), nJ(C,H) and nJ(C,F) values were determined. Generally, the nJ(C,F) coupling constants correlate with the length of the coupling route and thus simplify the assignments of the 13C NMR spectra. Only the side-chain carbons C-2 and C-3 in the ortho-substituted compounds showed an exception to this rule. Many long-range nJ(H,F) (n = 4–7) values were…
New potential DNA intercalators of the carbazole series from indole-2,3-quinodimethanes: Synthesis, crystal structure, and molecular modeling with a …
1993
1-Alkylpyrano[3,4-b]indol-3-ones3 react via a Diels-Alder step with an aryne or N-phenylmaleimide to furnish the new [b]annellated carbazoles4–10 in a one-pot process. In an analogous procedure, the in situ generated N-benzoylindole-2,3-quinodimethane (13) reacted with quinones to furnish the dioxocarbazoles14–16. Compounds4–8 and14–16 with a coplanar skeleton are members of a class of potential DNA intercalators, as has been shown for5 and8 by X-ray structural analysis. On the basis of the geometries determined by X-ray crystallography, the intercalative binding of these molecules with a Watson-Crick mini-helix was predicted by molecular modeling methods.
Single-crystal EPR study of the bimetallic ferrimagnetic chain MnCu(EDTA)·6H2O
1993
Abstract A single-crystal EPR study of the bimetallic chain compound MnCu(EDTA)·6H2O is reported. The angular dependence of the linewidth is discussed in relation to the magnetic dipole-dipole interaction, manganese zerofield splitting (ZFS) and copper hyperfine coupling. The calculation of the second moments indicates that ZFS is comparable to the dipolar contribution. The EPR data support the one-dimensional character of the compound.
Relaxation by Calcium Antagonists of Potassium-contracted Trachea from Normal and Sensitized Guinea-pigs: Influence of Epithelium and the Surface of …
1993
Abstract A technique by which drug access was restricted to either the mucosal or the adventitial surface of tracheal rings, isolated from normal (unsensitized) or sensitized guinea-pigs, was used to study the role of the epithelium in the relaxation produced by calcium antagonists (verapamil, nifedipine, cinnarizine and flunarizine) of K+-induced contraction. In trachea from normal guinea-pigs, the relaxation to verapamil for unrestricted or mucosal drug entry was reduced in the absence of epithelium, whereas the relaxation produced by nifedipine, cinnarizine or flunarizine was unchanged. In sensitized trachea, the relaxation elicited by the calcium antagonists tested was similar in intact…
The control of lava flow during the 1991–1992 eruption of Mt. Etna
1993
Abstract All the actions carried out in 1992 to protect the village of Zafferana Etnea from being invaded by lava are described. An earthen barrier 234 m long and 21 m high was firstly built in January 1992 by accumulating with mechanical escavators 370,000 m 3 of earth, scoriae and stones. This embankment contained the lava for about one month and was overflowed by April 9, 1992. Three additional smaller earthen barriers (lenght: 90–160 m; height: 6–12 m) were built in April to gain time while the lava front was descending towards Zafferana from the overflowed first embankment. The major effort of the 1992 operation consisted of several attempts at stopping the lava front advance by divert…
Self-assembly of bioelastomeric structures from solutions: Mean-field critical behavior and Flory-Huggins free energy of interactions
1993
Elastic and quasi-elastic light scattering studies were performed on aqueous solutions of poly (Val-Pro-Gly-Gly), a representative synthetic bioelastomer that differs from the previously studied poly (Val-Pro-Gly-Val-Gly) by the deletion of the hydrophobic Val in position four. When the spinodal line was approached from the region of thermodynamic stability, the intensity of light scattered by fluctuations, and the related lifetime and correlation length, were observed to diverge with mean-field critical exponents for both systems. Fitting of the experimental data allowed determining the spinodal and binodal (coexistence) lines that characterize the phase diagrams of the two systems, and it…
Resonance ionization mass spectroscopy for trace analysis of neptunium
1993
Resonance ionization mass spectroscopic (RIMS) measurements for trace analysis and spectroscopy of 237Np, the ecologically most important isotope of neptunium, are described. The chemical procedure for the separation of neptunium from aqueous samples as well as the preparation of filaments for RIMS are outlined. Several two- and three-step excitation schemes have been investigated in order to find suitable conditions for the sensitive detection of 237Np. Using a three-step, three-color excitation and ionization scheme an overall detection efficiency of 3×10−8 was obtained, resulting in a detection limit of 4×108 atoms (160 fg) of 237Np. The hyperfine structure splittings of the levels under…
Stereo and regioselectivity in the phenylation of cationic allylpalladium(II) α-diimine complexes by tetraphenylborate anion
1993
The reaction of the cationic complex [Pd(4-methoxy-1,3-η3-cyclohexenyl)(py-2-CHNC6H4OMe-4)]+ (1) with BPh4− in the presence of fumaronitrile yields trans-3-methoxy-6-phenylcyclohexene (2a) and trans-4-methoxy-3-phenylcyclohexene (2b), in ca. 1 : 1 molar ratio. The trans stereochemistry of these products implies that the phenylation of the allyl ligand involves prior transfer of a phenyl group from BPh4− to the metal, followed by reductive coupling of the organic moieties. In the reactions of [Pd(η3-1,1-R1,R2-C3H3)(NN′)]+ (3) [NN′ 4-MeOH4C6NCHCHNC6H4OMe-4; py-2-CHNR (R C6H4OMe-4, Me, or CMe3), 2,2′-bipyridine (bipy); R1 H, R2 Ph, Me; R1 R2 Me; with BPh4− in the presence of …
Evaluation of the representativeness of the odor of beer extracts prior to analysis by GC eluate sniffing
1993
The importance of obtaining and proving that the odor of an extract is representative of the odor of the original product from which it was obtained, before analysis by GC-FID, GC-MS, or GC sniff, is discussed. The sensory methods, such as triangle tests, matching tests, and quantitative analysis, used to determine the representativeness of the odor of an extract are described. Beer extracts obtained by three methods were used to illustrate the interest of the sensory tests. A method using a mixture of XAD resins was proved by sensory analysis to give some extracts with sensory characteristics representative of the particular beers from which they were obtained
Role of ondansetron plus dexamethasone in fractionated chemotherapy.
1993
This randomised, double-blind, parallel-group study was carried out to compare the efficacy and safety profile of ondansetron plus dexamethasone and metoclopramide plus dexamethasone in patients receiving fractionated cisplatin (20-25 mg/m2/day) chemotherapy for the treatment of testicular cancer. An interim analysis of 95 patients showed that the ondansetron regimen was significantly superior compared to the metoclopramide regimen (p0.001). According to the study protocol the study was terminated at this stage. At the time the decision to stop the study was taken, a total of 113 patients had been enrolled and were evaluable on an 'intention to treat' basis. Fifty-six of these had received …
On the use of mixing reactors in flow injection analysis with thermal lens calorimetric detection
1993
Abstract In flow injection analysis with thermal lens calorimetric detection, mixing of reagent streams of different composition before the detection cell produces a large background noise. The noise is due to the heterogeneity of the mixture which produces refractive changes in the probe beam direction. Procedures to measure the homogeneity of the mixture of solutions are derived, and used to evaluate and improve the mixing efficiencies of packed bead reactors. Using well-designed reactors, the mixing noise can be reduced below the noise levels due to other sources.
MR IMAGING AND HORMONAL FINDINGS IN PATIENTS WITH IDIOPATHIC GROWTH HORMONU DEFICIENCY
1993
Until the introduction of MR imaging in neuroradiological diagnostic, diagnosis of the ecotopic posterior pituitary lobe, first described by the pathologist Priesel in 1920, was rare. Recently it has increasingly been diagnosed by MR in patients whose anamnesis showed birth trauma. We performed MR of the hypothalamic-pituitary region in 17 patients with idiopathic growth hormone deficiency. 8 patients had additional deficiencies of the anterior pituitary lobe whereas the function of the posterior lobe of the hypophysis was normal in all patients. Indications of birth trauma were present in only 2 patients. The cause of anterior lobe insufficiency was determined by MR in 8 patients with panh…
Effect of histamine on the longitudinal and circular muscle of the oestrogen dominated rat uterus.
1993
The response of the longitudinal and circular myometrial strips to histamine was studied in oestrogen-treated rats. Histamine produced a dose-related inhibitory response in KCl-contracted longitudinal and circular uterine strips. Histamine was equipotent in producing the relaxant response but the maximal effect achieved in the longitudinal muscle was higher than the circular one. Ranitidine antagonized the histamine-induced relaxation with a similar dose ratio in both longitudinal and circular strips. Clemizole and reserpine treatment did not produce any modification of the dose-response curve to histamine. In the longitudinal and circular strips which were not preconstricted by KCl, neithe…
false
1993
In a new theoretical approach the separation of a pair of chain molecules (measured thermodynamically by the second osmotic virial coefficient A2) is treated as a two-step process: In the first step the molecules are detached from each other by the addition of solvent—keeping their dimensions constant—and in the second step the now isolated coils are allowed to relax into their equilibrium dimensions. For the description of the second step, in which only segments belonging to one molecule take part, an intra-molecular interaction parameter is introduced on the basis of the intrinsic viscosity. The present two-parameter approach yields A2 = A + σ M−(1−a) for the dependence of A2 on the molec…
Direct detection of repetitive, whole chromosome paint and telomere DNA probes by immunogold electron microscopy
1993
Biotinylated repetitive, whole chromosome paint and telomere DNA probes were investigated at the electron microscope level after non-isotopic in situ hybridization and direct immunogold detection. The protocol described allowed the visualization of a biotinylated chromosome 1 specific satellite DNA probe in the light microscope without silver intensification. This sensitive method was exploited to analyse factors contributing to signal strength in immunogold chromosome painting. Furthermore, it allowed us to investigate the distribution of (TTAGGG)n telomere repeats in human metaphase chromosomes and interphase nuclei. Telomeric and internal (TTAGGG)n repeats were detected at high spatial r…