showing 36 of ~574560 from 574555 documents
Visual memory in Alzheimer patients: effects of practice, retention interval and severity of cognitive decline.
1995
The study was aimed at estimating the effect size of practice, retention interval and dementia severity on free recall performance in Alzheimer patients. Patients met DSM-III-R criteria for dementia of Alzheimer type. Different picture sets were presented on 4 days. The forgetting curves on different days were compared using ANOVA for repeated measurements. Practice had a minor, but significant negative effect on recall performance explaining 1% of the variance in recall performance. The retention interval varied between zero and 24 h explaining 23% of the total variance. Dementia severity explained 52% of the variance. For the development of memory improvement strategies in Alzheimer patie…
Uveal effusion syndrome complicated by anterior ischemic optic neuropathy
1995
We report on a case of idiopathic uveal effusion syndrome complicated by AION. To our knowledge such an association hasn't been previously described. We suggest that scleral thickening caused obstruction of vortex veins followed by uveal effusion and compression of posterior ciliary arteries within their intrascleral tract, leading to AION. Nevertheless it can't be excluded that AION was the result of mechanical compression on ciliary vessels of optic disc by choroidal detachment. © 1996, Kluwer Academic Publishers. All rights reserved.
Income distribution dynamics: monotone Markov chains make light work
1995
This paper considers some aspects of the dynamics of income distributions by employing a simple Markov chain model of income mobility. The main motivation of the paper is to introduce the techniques of “monotone” Markov chains to this field. The transition matrix of a discrete Markov chain is called monotone if each row stochastically dominates the row above it. It will be shown that by embedding the dynamics of the income distribution in a monotone Markov chain, a number of interesting results may be obtained in a straightforward and intuitive fashion.
Effects of contralateral white noise stimulation on transitory evoked otoacoustic emissions in patients with acoustic neuroma.
1995
Abstract Transitory evoked otoacoustic emissions are normal phenomena observed in most persons with hearing levels greater than 35 dB. Further, masking of the contralateral ear produces amplitude reductions in the transitory evoked otoacoustic emissions. We have undertaken a study of transitory evoked otoacoustic emissions in 20 patients with acoustic neuroma. All patients were assessed for transitory evoked otoacoustic emissions bilaterally, with and without contralateral masking with white band noise at 40, 50, and 60 dB. We found that transitory evoked otoacoustic emissions were present in 30% of ears with tumor and that the presence of transitory evoked otoacoustic emissions is associat…
A theoretical study of the electronic spectrum of biphenyl
1995
Abstract The electronic spectrum of biphenyl in the energy range up to 6.0 eV has been studied using multiconfigurational second-order perturbation theory (CASPT2) and a basis set of ANO type, including polarization functions on all carbon atoms. The calculated spectrum gives conclusive assignments to all valence excited singlet states and the low-lying triplet states. The change of the torsional angle between the two benzene rings in the different excited states is shown to be of considerable importance and explains the different excitation energies observed in the gas phase as compared to solution or crystalline biphenyl at low temperatures. The intense transition to the 1 1B1u state is m…
Ferrocene containing chelating ligands 3. Synthesis, spectroscopic characterization, electrochemical behaviour and interaction with metal ions of new…
1995
Abstract Ferrocenecarboxaldehyde reacts with 2-amino-benzoic acid, 2-amino-5-methyl-benzoic acid or 3-amino-2-naphthoic acid to give the corresponding Schiff-base derivatives 2-ferrocenylmethylidenimino-benzoic acid (1), 2-ferrocenylmethylidenimino-5-methyl-benzoic acid (2) and 3-ferrocenylmethylidenimino-2-naphthoic acid (3). 1, 2 and 3 are stable in the solid state but easily hydrolyze in solution. This hydrolysis has been studied kinetically in a methanol-water medium. In order to increase the stability in solution to use these compounds as ligands, the imino group from 1, 2 and 3 was reduced by NaBH4 to give the amino derivatives 2-ferrocenylmethylamino-benzoic acid (4), 2-ferrocenylmet…
XAFS analysis of the low symmetry octahedral molybdenum and tungsten oxides
1995
Abstract Comparative XAFS analysis of the main isostructural crystalline phases of W(Mo)O3 oxides and W(Mo)O3·nH2O hydrates has been done at the W L3 and Mo K edges. These compounds have (1) 3D perovskite-type (PT) structure (m-WO3); (2) 2D PT structure (WO3·H2O and MoO3·nH2O (n = 1,2)); (3) 2D hexagonal-type structure (WO3·1/3H2O) and (4) 2D double layered structure (α-MoO3). The detailed analysis of X-ray absorption fine structure (XAFS) in the low-symmetry structures shows that in order to simulate the experimental spectrum, it is sufficient to take into account single-scattering contributions in the range from 1.7 to ∼ 5.0 A and a number of multiple-scattering paths from nearly linear a…
Characters with stable irreducible constituents
1995
Substituent effects on the spin equilibrium in iron(II) pyrazolylborate complexes
1995
Abstract Two new complexes of the iron(II) pyrazolylborate system, [Fe(HB(pz)(dmpz) 2 ) 2 ] and [Fe(HB(pz) 2 (dmpz)) 2 ] (pz = pyrazole, dmpz = 3,5-dimethylpyrazole), have been prepared and found to exhibit thermal spin crossover in toluene solutions by means of optical spectroscopy and magnetic susceptibility measurements. Comparison with the published magnetic behaviour of the complexes [Fe(HB(dmpz) 3 ) 2 ] and [Fe(HB(pz) 3 ) 2 ] shows that the high spin state is stabilized with an increasing number of methyl substituents.
Hexacyanoferrate (III) stimulation of elongation in coleoptile segments fromZea mays L.
1995
The influence of exogenous potassium hexacyanoferrate (III) (HCF III) on elongation of maize (Zea mays L.) coleoptile segments was investigated. Addition of HCF III led to a strong stimulation of growth both in the presence and absence of indole-3-acetic acid (IAA). The magnitude of growth stimulation was dependent on the presence of IAA, HCF III concentration, incubation time, and phase growth. The reduced form, potassium hexacyanoferrate (II), was without effect on growth. In the presence of HCF III, elongation was suppressed when coleoptile segments were treated with N,N′-dicyclohexylcarbodiimide, cycloheximide or atebrine (quinacrine). The addition of HCF III stimulated the IAA-induced …
Nitric oxide synthase-immunoreactive vagal afferent fibers in rat superior cervical ganglia
1995
Abstract Chronic (5–14 days) preganglionic denervation of the rat superior cervical ganglia by sectioning the cervical sympathetic trunk resulted in a time-related partial or complete loss of nitric oxide synthase (isoform I)-immunoreactive fibers and terminals surrounding many sympathetic ganglionic neurons. Unexpectedly, denervation unmasked many varicose nitric oxide synthase-immunoreactive fibers, some of which could be traced the entire length of the superior cervical ganglia. Injection of the retrograde tracer Fluorogold into the superior cervical ganglia labeled a population of nodose ganglion cells and of dorsal root ganglion cells from C8 to T3 segments. When the same sections were…
STUDY OF SHORT-LIVED SILVER ISOTOPES WITH A LASER ION-SOURCE
1995
A chemically selective laser ion source based on resonance ionization of atoms in a hot cavity has been applied for the study of short-lived silver isotopes at CERN/ ISOLDE. Silver atoms were ionized by two resonant excitations and final laser ionization into the continuum. Decay properties of the neutron-rich isotopes121–127Ag were studied with a neutron long-counter and aβ-detector.
A study on spectral optimisation in partial response CPM signals
1995
An optimisation technique for the minimisation of the effective bandwidth in partial response CPM signals is described. The minimum Euclidean distance is used as optimisation constraint because the bit error probability is a function of this parameter for high values of signal to noise ratio. The procedure has been implemented for a correlation length corresponding to two signalling intervals. The optimisation problem leads to a system of two nonlinear differential equations for the pulse shape, together with some boundary conditions. Numerical solution of the differential equations has been performed; initial conditions have been adjusted, to satisfy the boundary conditions using an iterat…
A star-product approach to noncompact Quantum Groups
1995
Using duality and topological theory of well behaved Hopf algebras (as defined in [2]) we construct star-product models of non compact quantum groups from Drinfeld and Reshetikhin standard deformations of enveloping Hopf algebras of simple Lie algebras. Our star-products act not only on coefficient functions of finite-dimensional representations, but actually on all $C^\infty$ functions, and they exist even for non linear (semi-simple) Lie groups.
Short range correlations in the weak decay of Λ hypernuclei
1995
The geometry of surfaces in 4-space from a contact viewpoint
1995
We study the geometry of the surfaces embedded in ℝ4 through their generic contacts with hyperplanes. The inflection points on them are shown to be the umbilic points of their families of height functions. As a consequence we prove that any generic convexly embedded 2-sphere in ℝ4 has inflection points.
Nonlinear analysis of sleep eeg in depression: Calculation of the largest lyapunov exponent
1995
Conventional sleep analysis according to Rechtschaffen and Kales (1968) has provided meaningful contributions to the understanding of disturbed sleep architecture in depression. However, there is no characteristic alteration of the sleep cycle, which could serve as a highly specific feature for depressive illness. Therefore, we started to investigate nonlinear properties of sleep electroencephalographic (EEG) data in order to elucidate functional alterations other than those obtained from classical sleep analysis. The application of methods from nonlinear dynamical system theory to EEG data has led to the assumption that the EEG can be treated as a deterministic chaotic process. Chaotic sys…
The Crystal Structure of Nickel(II)-Azurin
1995
The nickel(II)-azurin metalloderivative has been crystallized and its structure solved at 0.205-nm resolution by X-ray diffraction. The overall structure is not modified by the metal exchange and the only differences with regard to the native copper(II)-azurin occur in the metal site region. These variations affect principally the axial ligands. Nickel co-ordinates more strongly to the carbonyl oxygen of Gly45 while its distance to the Met121 S4 enlarges up to 0.330 nm. The resulting metal center structure is intermediate between those of the Cu(II) and Zn(II) azurins, and can be described as distorted tetrahedral. However, the existence of contact interaction between Met121 and the nickel …
Parton polarization and constituent quarks
1995
Abstract A systematic study of the polarized-parton distributions is presented and related to the properties of the constituent quarks. The effects of breaking SU(6) symmetry are emphasized and the Isgur-Karl constituent model is discussed in detail. The results on the proton, neutron and deuteron structure functions are compared with the recent experimental data, and the role of the gluon polarization is pointed out. The role of the D-state admixture in the nucleon ground state is also investigated.
High-performance micellar liquid chromatography determination of sulphonamides in pharmaceuticals after azodye precolumn derivatization
1995
Abstract A chromatographic procedure with precolumn derivatization to form the N-(1-naphthyl)ethylenediamine dihydrochloride azodyes is proposed for the analysis of several sulphonamides (sodium sulphacetamide, sulphadiazine, sulphaguanidine, sulphamerazine, sulphamethizole, sulphamethoxazole, sulphanilamide and sulphathiazole) in pharmaceutical preparations (tablets, pills, capsules, suspensions and drops). The separation is performed with a 0.05 M sodium dodecyl sulphate/2.4% pentanol eluent at pH 7. The precolumn derivatization improved the resolution in the chromatograms and increased the selectivity in the determination of mixtures of sulphonamides and in preparations where other drugs…
Pulmonary aspergilloma in a patient with AIDS.
1995
Aspergillus infections are rare in the course of AIDS. They mostly occur as invasive destructive disease in patients with severe CD4 cell depletion. An unusual case of a homosexual AIDS patient who developed a pulmonary aspergilloma is presented.
Non-critically phase-matched cascaded THG at 440 nm in KTiOP1−yAsyO4 crystals
1995
Abstract We report the relative nonlinear optical properties of flux-grown KTiOP 1− y As y O 4 crystals ( y =0, y =0.03 and y =0.12). The non-critical phase-matching temperatures along the x -axis for blue generation by type II indirect third harmonic generation from 1318.8 nm and 1320 nm are measured. The phosphorus-arsenic substitution allows a “chemical tuning” of the phase-matching properties, through a birefringence variation, so that non-critical phase-matching at room temperature is possible for the previous interactions. Type II frequency doubling from 1064 nm is briefly considered.
Comparison of the metabolism of 7-ethoxycoumarin and coumarin in precision-cut rat liver and lung slices
1995
The metabolism of 7-ethoxycoumarin and [3-(14)C]coumarin was compared in precision-cut rat liver and lung slices. The lung slices were prepared using an agarose gel instilling technique enabling the production of tissue cylinders followed by lung slices employing a Krumdieck tissue slicer. Both 50 microM 7-ethoxycoumarin and 50 microM [3-(14)C]coumarin were metabolized by rat liver and lung slices. 7-Ethoxycoumarin was converted to 7-hydroxycoumarin (7-HC) which was conjugated with both D-glucuronic acid and sulfate. 7-HC sulfate was the major metabolite formed by both liver and lung slices. [3-(14)C]Coumarin was metabolized by rat liver and lung slices to both polar products and to metabol…
Clara Eugenia Núñez y Gabriel Tortella (eds.), La maldición divina. Ignorancia y atraso económico en perspectiva histórica, Madrid, Alianza Universid…
1995
The analysis of modified peroxisome proliferator responsive elements of the peroxisomal bifunctional enzyme in transfected HepG2 cells reveals two re…
1995
AbstractPeroxisome proliferators (PPs) are non-genotoxic carcinogens in rodents. They can induce the expression of numerous genes via the heterodimerization of two members of the steroid hormone receptor superfamily, called the peroxisome proliferator-activated receptor (PPAR) and the 9-cis retinoic acid receptor (RXR). Many of the PP responsive genes possess a peroxisome proliferator response element (PPRE) formed by two TGACCT-related motifs. The bifunctional enzyme (HD) PPRE contains 3 such motifs, creating DR1 and DR2 sequences. PPAR and RXR regulate transcription via the DR1 element while DR2 modulates the expression of the gene via auxiliary factors in HepG2 cells.
Solid-phase extraction on C18 in the trace determination of selected polychlorinated biphenyls in milk.
1995
The utility of solid-phase extraction with octadecylsilica for determining fifteen polychlorinated biphenyl (PCB) congeners from milk samples was examined. Recoveries higher than 80% and relative standard deviations better than 10% were obtained for PCBs from different kinds of milk (whole, skimmed, 2%, powdered, breast and evaporated). A comparison with other procedures was made. The described method provides better detection limits than those attainable with the liquid-liquid extractions currently used as standard methods, when capillary gas-liquid chromatography is used for the final determination. A study of the separation was also performed using six different fused-silica capillary co…
QCD Radiative Correction to Zero Recoil Sum Rules for Heavy Flavor Transitions in the Small Velocity Limit.
1995
We consider the small velocity sum rules for heavy flavour semileptonic transitions that are used to estimate the zero recoil values of semileptonic heavy flavour form factors. We analyze the complete O($\alpha _S$) radiative correction to these sum rules. The corrections are universal and influence all "model-independent" bounds previously derived for semileptonic form factors at zero recoil.
Weak decays of doubly heavy hadrons
1995
We explore the application and usefulness of the heavy quark symmetry to describe the weak decays of hadrons (mesons and baryons) containing two heavy quarks. Firstly, we address the internal dynamics of a heavy-heavy bound system with the help of estimates based on potential models, showing an approximate spin symmetry in the preasymptotic quark mass region including charmonium, bottonium and $B_c$ meson states. However, no asymptotic spin symmetry should hold in the infinite quark mass limit in contrast to singly heavy hadrons. Predictions on semileptonic and two-body nonleptonic decays of $B_c$ mesons are shown. Furthermore, the stemming flavor and spin symmetries from the interaction be…
The membrane distal half of gp130 is responsible for the formation of a ternary complex with IL-6 and the IL-6 receptor
1995
AbstractGp130 is the signal transducing subunit of the interleukin-6 receptor. Signaling is initiated by the complex formation of gp130 with IL-6 bound to the IL-6 receptor (IL-6R). We have subdivided the extracellular domain of gp130 in two parts and expressed the mutant proteins as soluble IgG fusion proteins in COS-7 cells. By studying the formation of the ternary complex we show that the membrane distal half of gp130 which contains a cytokine receptor domain is responsible for the interaction with the IL-6/IL-6R complex. Interestingly this is the same region which is believed to be involved in specific recognition of the related cytokines LIF, OM, and probably also of CNTF and IL-11.
Acyl-CoA intermediates in the beta-oxidation of ricinoleic acid and palmitoic acid by extracts of Fusarium poae INRA FP45
1995
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Binding ability of N-Para-amino-phenylsulfonyl derivatives of amino acids. Potentiometric and spectroscopic studies of Cu(II) complexes
1995
Abstract N-Para-amino-phenylsulfonyl derivatives of amino acids are very effective ligands for Cu(II) ions. Potentiometric and spectroscopic results have shown that Cu(II) ions are able to deprotonate and bind to sulfonamide nitrogen below pH 5 to form stable mono- and bis-[N − , COO − ] chelates. The basicity of sulfonamide nitrogen is lower than peptide amide nitrogen and no distinct anchoring site is necessary to promote the amide nitrogen deprotonation.
Metal complexes of the carbonic anhydrase inhibitor methazolamide (Hmacm). Crystal structure of the Zn(macm)2 (NH3)2. Anticonvulsant properties of th…
1995
Complexes of Co(II), Cu(II), and Zn(II) with deprotonated methazolamide and ammonia are synthesized and characterized. The complex Zn(macm)2(NH3)2 crystallizes in the monoclinic C2/c space group with a = 13.468(1), b = 6.759(1), c = 23.014(2) A, beta = 90.27(1), and Z = 4. The structure was refined to R = 0.049 (Rw = 0.053). The Zn(II) ion is coordinated to two deprotonated sulfonamido nitrogen atoms of the macm- ligand and two nitrogen atoms of the ammonia ligands in a distorted tetrahedron. The Zn(macm)2(NH3)2 complex is shown to be a simple model for the methazolamide inhibition of CA. EHMO calculations applied to fractional coordinates of the Zn(macm)2(NH3)2 complex indicate that the at…
Structural properties ofSi1−xGexalloys: A Monte Carlo simulation with the Stillinger-Weber potential
1995
The structural properties of binary silicon-germanium alloys are investigated by means of large-scale constant-pressure Monte Carlo simulations of the Stillinger-Weber model. At low temperatures, the binary-mixture phase separates into Si-rich and Ge-rich phases. The two-phase coexistence region is terminated by a critical point that belongs to the mean-field universality class. We also studied the structural properties of pure Si and Ge as well as the binary mixture. In particular, we found that the linear thermal expansions for both Si and Ge are in agreement with experiments, and that V\'egard's law is valid at temperatures above the critical point. Finally, we compare the bond-length an…
Estimation of water vole abundance by using surface indices
1995
A method to estimate the abundance of the fossorial form of the water vole Arvicola terrestris scherman (Shaw, 1801) has been developed, by using surface indicies. Results are compared to the standard method of estimation using trap lines.
Onco-fetal/laminin-binding collagen from colon carcinoma: detection of new sequences.
1995
We have recently identified an oncofetal-laminin binding collagen (OF/LB) composed of three alpha chains, with the apparent molecular mass of about 100 kDa each, but bearing different pI. One of the chains appears markedly acidic in a bidimensional electrophoretic system, where the NEPHGE is used as first dimension separating gel, while the two more basic chains have similar migration as alpha 1(III) and alpha 1(I) collagen chains, respectively. Sequence analyses have been performed on CNBr-peptides, derived from pepsinized triple helical molecules and on tryptic fragments obtained after in gel digestion of the acidic band. The research of sequence homology with computerized databases indic…