Study of the Spin Wave Linewidth in a 1-D Easy-Plane Ferromagnet Using Neutron Polarization Analysis

1990

An anomalous wavevector dependence in the spin wave linewidth associated with fluctuations out of the easy plane is observed for the first time in the one-dimensional easy-plane ferromagnet CsNiF3 by means of inelastic polarized neutron scattering. The linewidths of the spin waves, one attributed to spin fluctuations out of the easy plane and another in the easy plane, are studied separately throughout the Brillouin zone. The zone boundary narrowing of the linewidth associated with the spin fluctuations in the easy plane is observed for the first time in agreement with the classical spin wave theory. The deviations from the classical result at large qc and high temperature are interpreted a…

Determination of the protein and free amino acid content in a sample using o-phthalaldehyde and N-acetyl-L-cysteine

1990

A spectrophotometric method is proposed for determining the protein content in a sample after total acid hydrolysis. In the procedure, free amino acids are caused to react with o-phthalaldehyde and N-acetyl-L-cysteine at pH 9.5, using isoleucine as the reference compound. Correction factors are used to take into account the differences between the molar absorptivities of the amino acid isoindoles and the recoveries of the amino acids after the hydrolysis treatment. The limit of detection was in the range 40-50 micrograms of protein, and the recoveries were usually 101 +/- 3% with a coefficient of variation lower than 4%. The free amino acid content in a partially hydrolysed protein was also…

Monte Carlo studies of finite-size effects at first-order transitions

1990

Abstract First-order phase transitions are ubiquitous in nature but their presence is often uncertain because of the effects which finite size has on all transitions. In this article we consider a general treatment of size effects on lattice systems with discrete degrees of freedom and which undergo a first-order transition in the thermodynamic limit. We review recent work involving studies of the distribution functions of the magnetization and energy at a first-order transition in a finite sample of size N connected to a bath of size N′. Two cases: N′ = ∞ and N′ = finite are considered. In the former (canonical ensemble) case, the distributions are approximated by a superposition of Gaussi…

Ferroelastic phase transitions of alkali halide-alkali cyanide mixed crystals

1990

Abstract The alkali cyanides and their CN-rich mixtures with alkali halides are proper ferroelastics with transitions from the cubic high temperature phase into the various non-cubic low temperature phases. As the CN concentration is reduced, the transformations temperature decreases and eventually the ferroelastic low temperature state is suppresse in favour of a glass-like state. The structural and elastic properties of these compounds are discussed with a special emphasis on the martensitic aspect of the transitions.

A simple geometrical model for analysing the spectral response of a citrus canopy using satellite images

1990

Abstract A simple geometrical model has been proposed for a citrus canopy. We assume the citrus orchard to be a lattice structure, with the trees positioned at its points and where the composite-scene reflectance is the sum of the reflectance of its individual components as weighted by their respective surfaces within a unit area. The model has been used to analyse the citrus spectral response obtained from Landsat-5 TM images for winter and summer, where the status of the orchard is different. The correlations between spectral and geometrical data show the influence of per cent crop cover, shadows and background in the composite scene reflectance. We conclude that the summer images could b…

false

1990

Taking into account the dependency on molar mass of the viscometric interaction parameter B, the modified Stockmayer-Fixman-Burchard equation ([η]/M1/2) = KΘ + C″ · A2 · M1/2 is obtained. It relates the intrinsic viscosity, [η], to the second virial coefficient, A2, and to the unperturbed dimensions parameter, KΘ, with C″ being a constant. Hereupon, KΘ can be determined from [η] and A2 data of any binary (solvent/polymer) and/or ternary (solvent 1/solvent 2/polymer) system, BPS and/or TPS. Because of the scarcity of reliable sets of [η] and A2 values mostly for TPS, the application of the above equation to obtain KΘ coefficients rests limited. This limitation can be surmounted by an A2 eval…

Why the Universe is not a fractal

1990

L'etude du survey des redshifts CfA montre que la distribution des galaxies dans l'Univers obeit a une loi d'echelle sur des echelles de longueur inferieures a environ 5 h −1 Mpc. Cependant, l'Univers n'est pas bien represente par une fractale homogene sur ces echelles. La dependance de la longueur de correlation avec la profondeur des echantillons et la luminosite est etudiee. Une methode basee sur l'arbre maximal est presentee pour determiner la dimension de Hausdorff d'une distribution de points. Cette technique est ensuite appliquee au catalogue CfA

Autoimmunity and liver disease

1990

Standard partial molar volumes of alcohols in aqueous dodecyltrimethylammonium bromide solutions

1990

Density measurements of water-dodecyltrimethylammonium bromide (DTAB)-alcohol ternary systems as a function of alcohol and surfactant concentrations were carried out at 25°C. The alcohols were propanol (PrOH), 2-propanol (2-PrOH) and hexanol (HexOH). The apparent molar volume Vϕ,R of alcohols have been calculated and the standard (infinite dilution) partial molar volumes of alcohols V R at each surfactant concentration were obtained by means of a least squares fit of Vϕ,R vs. the alcohol concentration. The V R vs. surfactant concentration curves have been rationalized in terms of the partial molar volume of alcohol in the aqueous V f and the micellar V b phases and the distribution constant…

Oxygen and substrate deprivation on isolated rat cardiac myocytes : temporal relationship between electromechanical and biochemical consequences

1990

The effects of hypoxia and reoxygenation on action potentials (AP), contractions, and certain biochemical parameters were studied in isolated rat ventricular myocytes in monolayer culture in the presence and absence of glucose. Substrate deprivation alone had no influence on the basal properties. In the presence of glucose, a 4-h hypoxic treatment caused only a moderate decrease in AP amplitude and rate. In substrate-free conditions, hypoxia induced a gradual decline in plateau potential level and in AP duration and rate, followed by rhythm abnormalities and a failure of the electromechanical coupling. Spontaneous AP generation then ceased, and the resting potential decreased with increase…

Effects of maxillary protraction determined by laser metrology

1990

In this work we studied some of the main effects of the maxillary protraction orthopedic device. The initial dento-craniofacial reactions induced by maxillary protraction similar to that commonly employed in clinical practice are reported. The fringe counting holographic interferometry technique is used to measure displacements. The experiments were performed on a dried human skull; traction application points were situated over the permanent lateral incisors or over the first permanent molars. The results fundamentally reveal an anterior rotation of the dentomaxillary complex, more intense when traction is applied to the lateral incisors, as shown by a more marked extrusion of the molars i…

Influence of oxygen vacancies on the photorefractive effect in barium titanate single crystals

1990

Abstract In this work the influence of the vacancies concentration in pure BaTiO3 single crystals is studied. It is shown that the oxidation and the reduction do not change the electrooptic coefficients. The reduction modifies the nature of the majority carriers. An evaluation of the trap density N is done.

Caii H and K spectroscopic observations in active binary systems

1990

We have performed high resolution spectroscopic observations of five active binary systems in the Caii H and K lines at La Palma Observatory. We present the absolute fluxes calculated at the surface of the stars and we discuss the spectral characteristics observed, presence of double emissions and phase variations.

Correlated e+ e− peaks observed in heavy-ion collisions

1990

Abstract Three very narrow e + e − sum-energy peaks around 610, 750, and 810 keV have been observed in U+Th as well as in U+Ta collisions at beam energies around the Coulomb barrier. As no processes involving conventional atomic and nuclear physics were found to describe their origin, the data were in particular confronted with the hypothesis that the lines are due to the two-body decay of neutral objects in an e + e + pair. Although the 810 keV sum-energy line observed in U+Th is consistent with the prompt two-body e + e − decay of a neutral object if created nearly at rest in the heavy-ion center-of-mass system, the other lines require at least a considerably more complicated scenario if …

The relation between cycling time to exhaustion and anaerobic threshold.

1990

This study investigated whether the anaerobic threshold (AnT) could be used to predict prolonged work capacity measured as cycling time to exhaustion (= endurance time) and which factors, in addition to relative exercise intensity, could explain variation in endurance time. Theoretical exercise intensities corresponding to certain endurance times were also calculated. The hyperbolic and exponential functions between cycling time and relative work rate (WR[%]), as well as between cycling time and relative oxygen uptake (VO2[%]) were fitted to the pooled data (n = 45) of 17 subjects. The WR(%) and VO2(%) were expressed as a percentage of the subject's own AnT- and maximum-values. At WR corres…

Analgosedierung bei neurochirurgischen Intensivpatienten

1990

Different concepts for analgosedation of neurosurgical patients are recommended during postoperative ventilation. In 30 neurosurgical patients (2 groups of 15 patients), we studied a continuous i.v. application of alfentanil (Rapifen) and midazolam (Dormicum) compared to an application of continuously given alfentanil with discontinuously given midazolam. A good analgosedation (i.e. sufficient sedation with good neurological judgement) was more frequently achieved (8/15 patients) by continuous application of both substances (alfentanil 0.023 mg/kg b.w./h, midazolam 0.10 mg/kg b.w./h), compared to discontinuous application of midazolam (4.5/15 patients; alfentanil 0.028 mg/kg b.w./h, midazol…

false

1990

Intrinsic viscosities, [η], second virial coefficients, A2, and interaction potentials, g12, for the ternary systems alcohol (1)/3-heptanone (2)/poly(1-vinyl-2-pyrrolidone) (3), with the unbranched alcohols methanol, ethanol and 1-propanol, were determined at 25°C. Taking into account the dependence of the viscometric interaction parameter, B, with the molecular weight of the polymer, the unperturbed dimensions parameter, KΘ, of the polymer was unambiguously obtained. Relationships between ΔKΘ (defined as ΔKΘ = ΔK − KΘ) and excess Gibbs energies, GE, and between excess viscosity, Δ[η], and GE allow to obtain equations relating A2 to ΔKΘ or to Δ[η]. Therefore, A2 can be evaluated from experi…

An electrophysiological study of the ontogenesis of adenosine receptors in the CA1 area of rat hippocampus

1990

Abstract The depressant effect of adenosine (Ad) was studied electrophysiologically in hippocampal slices from 5-, 10-, 15-, 20-, 30- and 120-day-old rats. Ad (10μM) depressed the field EPSP in CA1 to the same extent in all age groups. Caffeine (Caf), an Ad receptor antagonist, enhanced and nitrobenzylthioinosine (NBI), an Ad uptake blocker, depressed the field EPSP. Both these effects were, however, less prominent in slices from younger animals, a finding consistent with lower extracellular levels of endogenous Ad in neonatal rats.

Second-order approximations to laser-assisted charged-particle scattering.

1990

Multiphoton free-free transitions within a full second-order treatment of the scattering potential are considered with two specific aims: (i) to test some widely used approximations against exact calculations; (ii) to present differential cross sections for the laser-assisted positron scattering, in the regime of intermediate field intensities (up to ${10}^{13}$ W/${\mathrm{cm}}^{2}$). In the case of a field linearly polarized along the incident particle momentum, the results clearly discriminate among the approximations, setting interesting limitations to each of them as functions of the scattering potential features and of the field parameters. Each approach shows good performance for par…

A distributed dynamic load balancer and its implementation on multi-transputer systems for molecular dynamics simulation

1990

Abstract A new and efficient approach is described to the dynamic load-balancing problem which is central in concurrent computing. A transputer-based implementation is tested on a molecular dynamics simulation of spinodal phase separation.

Comparison of hard vaporization and soft ionization techniques in the mass spectrometry of some palladium(II) and platinum(II) complexes with C-bonde…

1990

Abstract Electron impact, fast atom bombardment and laser induced vaporization techniques are compared in the mass spectrometric behaviour of some palladium(II) and platinum(II) complexes with C-bonded heterocyclic ligands of the type trans -[MCl(R N )(PPh 3 ) 2 ] [M = Pd, R N = 2-pyridyl, 1 ; 2-pyrazyl, 2; 2-pyrimidyl, 3; M = Pt, R N = 2-pyridyl, 4 ].

Sur les Codes ZigZag et Leur Décidabilité

1990

AbstractThis paper deals with zigzag factorizations and zigzag codes. The language of “zigzag” over a regular language is represented by constructing a special family of two-way automata. Decidability of zigzag codes, previously shown for the finite languages, is proved here for all regular languages by the analysis of the set of “crossing sequences” produced by a two-way automation in the family. We also obtain that it is decidable whether or not a two-way automation of a certain type is non-ambiguous.RésuméDans ce papier on reprend les notions de factorisation zigzag et de code zigzag. On construit pour tout langage rationnel, une famille d'automates bilatéres lesquels reconnaissent les m…

Complex formation equilibria between the acetazolamide ((5-acetamido-1,3,4-thiadiazole)-2-sulphonamide), a potent inhibitor of carbonicanhydrase, and…

1990

Abstract The stability constants for the equilibrium of complexation between acetazolamide and the divalent metal ions copper(II), nickel(II), zinc(II), and cobalt(II) have been determined by potentiometry both in water and in water-ethanol 50 vol. % solutions in 0.15 mol dm −3 NaNO 3 at 25°C. This mixed solvent has been used in order to obtain higher concentrations of acetazolamide in solution. For copper(II) and nickel(II), the binuclear species [Cu 2 (Acm) 2 ] and [Ni 2 (Acm) 3 ] 2− are detected in both solvents together with hydroxo species. The values of the stability constants are always higher in the mixed solvent than in water. For cobalt(II) and zinc(II), while in aqueous solution …

Development of HPLC methods for the purification and analysis of plasma membrane glycoproteins.

1990

High resolution HPLC techniques such as affinity chromatography (AC), ion exchange chromatography (IEC), and size exclusion chromatography (SEC) were used successfully for separations of hydrophobic plasma membrane glycoproteins. We have tested a lot of commercially available columns for IEC and SEC and performed the purification of the crude plasma membrane extract with the most suitable columns. By using immobilized ligands with different specificities and sequential affinity chromatography, it is possible to obtain a preliminary structural characterization of the interesting carbohydrate residues of membrane glycoproteins.

The First Clamped and Strongly Deformed Adamantane

1990

Effect of beclomethasone dipropionate on the bronchial responsiveness to propranolol in asthmatics.

1990

The effect of four weeks of treatment with beclomethasone dipropionate (BDP, 500 micrograms twice daily) on the bronchial responsiveness to propranolol was examined in 16 patients with mild asthma in a placebo-controlled, double-blind crossover study. Propranolol was inhaled in doubling concentrations and the results were expressed as the cumulative dose producing a 20 percent fall in FEV1 (PC20). After four weeks of treatment with BDP, the mean FEV1 increased from 82.0 percent predicted to 88.1 percent predicted. The difference was significant (p less than 0.001). Treatment with BDP did not significantly change the responsiveness to propranolol, the geometric mean PC20 being 3.17 mg/ml bef…

In-vitro assessment of centrifugal pumps for ventricular assist.

1990

Currently two major types of centrifugal pumps are commercially available for ventricular assist: the Biomedicus-cone (Group I) and the Centrimed-impeller pump (now Sarns 3M) (Group II). To compare them for blood trauma and hemolysis, an in-vitro experiment was designed with a Stockert roller pump as a standard control (Group III). The in-vitro circuit was constructed consisting of a pump head, electromagnetic flow probe, polyvinyl chloride tubing and a reservoir, identical for all groups. Human ACD blood was used for priming and was circulated with a flow rate of 2 L/min for 24 h. Blood samples were taken at 0, 1, 3, 6, 12, and 24 h and zero control values were subtracted from the resultin…

Das erste verklammerte und stark deformierte Adamantan

1990

Genetic and molecular analysis of six tumor suppressor genes in Drosophila melanogaster

1990

Six Drosophila melanogaster tumor suppressor genes causing malignant or benign tumors in specific cell types are described. The wild-type alleles of these genes are instrumental in the differentiation of particular cell types. In the homozygous state, recessive mutations in the genes interrupt the differentiation of the cells and thus cause their uncontrolled, autonomous, lethal proliferation. The tumors show all major characteristics of malignant and benign neoplastic growth. Genomic sequences of four of the genes have been identified and are currently being characterized. ImagesFIGURE 1.FIGURE 2.FIGURE 2.

Identification of protein IT of the intestinal cytoskeleton as a novel type I cytokeratin with unusual properties and expression patterns.

1990

A major cytoskeletal polypeptide (Mr approximately 46,000; protein IT) of human intestinal epithelium was characterized by biochemical and immunological methods. The polypeptide, which was identified as a specific and genuine mRNA product by translation in vitro, reacted, in immunoblotting after SDS-PAGE, only with one of numerous cytokeratin (CK) antisera tested but with none of many monoclonal CK antibodies. In vitro, it formed heterotypic complexes with the type II CK 8, as shown by blot binding assays and gel electrophoresis in 4 M urea, and these complexes assembled into intermediate filaments (IFs) under appropriate conditions. A chymotrypsin-resistant Mr approximately 38,000 core fra…

Modified hydrodynamic chromatography and its applications to liposomes

1990

Penumbral oscillations in Na D lines

1990

Penumbral oscillations were measured in two opposite parts in the penumbra of a spot, using photographic spectra of Na D lines. Power spectra of velocities show the presence of the 5-min oscillation with lowv rms. Coherence and phase analyses between the velocity fluctuations of the lines are also studied. The results seem to show that the 5-min oscillation is still surviving as a standing or evanescent wave at the height of formation of Na D lines.

Triiodothyronine accelerates the synthesis of synapsin I in developing neurons from fetal rat brain cultured in a synthetic medium.

1990

The effect of Triiodothyronine (T3) on Synapsin I appearance in rat cortical neurons has been investigated in vitro. Neuronal cultures from 16-day-old fetal rat brain grown in the absence of T3, express immunohystochemically detectable Synapsin I at the 14th day in vitro. The addition of the hormone to the culture medium determines an early (at the 7th day in vitro) appearance of fluorescent dots specific for Synapsin I. © 1990 Plenum Publishing Corporation.

Corynebacterium parvum (Propionibacterium acnes): an inducer of tumor necrosis factor-alpha in human peripheral blood mononuclear cells and monocytes…

1990

The present study investigates the potential capacity of the immunostimulant Corynebacterium parvum (C.p.) to induce tumor necrosis factor-alpha (TNF-alpha) in human peripheral blood mononuclear cells (PBMC) and blood monocytes (BMo) in vitro. Both at the mRNA and protein level, stimulation of PBMC and BMo upon C.p. induces TNF-alpha. Compared to the hitherto used TNF-alpha inducers in vitro such as Sendai virus, phytohemagglutinin or lipopolysaccharide the C.p. stimulus displayed a threefold stronger induction of TNF-alpha production (p less than 0.001). Using C.p. as an inducer it was possible to demonstrate that TNF-alpha production is regulated by prostaglandin E2; preincubation of the …

Magnetic order in the heavy fermion system Ce(Cu1−xNix)2Ge2

1990

Abstract The magnetic phase diagram of the heavy fermion (HF) systems Ce(Cu 1−x Ni x ) 2 Ge 2 is discussed utilizing results of transport, thermodynamic and neutron-scattering measurements. While the Kondo temperature increases monotonically with x, a complex x-dependence is found for the Neel temperature, associated with a transition from local-moment to itinerant HF magnetism.

Disulfide bridge formation between C1q and IgG in vitro.

1990

The globular heads of C1q are known to possess free-SH groups. Here we show that these groups, which are concealed in the native molecule, are exposed by interaction of C1q with dialysis membrane. During iodination, I+ and I2 oxidize these sulfhydryls to produce disulfide-linked C1q aggregates. Approximately 15% of C1q bound to immunoglobulin aggregates is resistant to high conductivity elution and reducing agent is required to release it. These data show that dialysis, adsorption to Ig and iodination of C1q result in structural and functional changes in the molecule, and suggest a mechanism by which these changes occur. Disulfide bridging between C1q and IgG in vitro suggests that this may…