The effects of electroconvulsant shocks on phagocytic activity and on phagocytic response

The influence of a single or several subsequent convulsant electroshocks at different time laps (2-4 day), over a month, on the phagocytic activity was studied on seven dogs. The electroconvulsant shock was performed with bitemporal electrodes, at a liminal electric power. Phagocytosis was studied in vitro with amidon particles in whole blood, incubated 1h at 37 degrees C. After 4 hours the phagocytosis increases in all animals and remains higher for 12 days. Later on the repeated shocks produce very different changes of the phagocytic activity, depending, not only on the stressor agent, but also on the animal particular reactivity, conditioned genetically and by its individual history.     

SEM investigations of iron surface ion erosion as a function of specimen temperature and incidence angle

Ion bombardment of iron surfaces produced an ion eroded surface microtopography strongly dependent on the incidence angle and specimen temperature. For bombardment temperatures exceeding the self-diffusion temperature, T _d, a microstructural smoothing process due to the thermally activated diffusion effects, assisted by ion bombardment, can be observed by SEM. The role of migrational processes which should be taken into account for a correct interpretation of the final surface topography formed by hot sputtering, was also considered.     

A fuzzy information space approach to speech signal non‐linear analysis

A new approach for analyzing the similarity of dynamical systems is presented, with applications to speech analysis. This approach is based on a temporal fuzzy set representation of the trajectories of the dynamical system. The similarity between segments of the speech signal is determined via similarity measures of the corresponding temporal fuzzy sets. We present an application of the method to vowel recognition in the samples (amplitude–time) space. © 2000 John Wiley & Sons, Inc.     

Pulsed laser deposition of silicon nitride thin films by laser ablation of a Si target in low pressure ammonia

We report the deposition of Si-N films by multipulse excimer laser ( = 308 nm, _FWHM = 30 ns) ablation of Si wafers placed in a slow flow of NH₃ in the pressure range (1 bar-1 mbar). The films are deposited on to a Si collector placed parallel to the Si target. We succeeded in depositing pure amorphous Si₃N₄ films at a pressure of 1 mbar of NH₃. The deposition rate reached a maximum value of 0.2–0.3 nm per pulse. At lower pressures, the deposited films consist of a fine mixture of three amorphous phases (amorphous stoichiometric silicon nitride, amorphous non-stoichiometric silicon nitride and amorphous silicon). The amorphous silicon is prevalent in films deposited at a pressure of several to several tens of bars. Droplets of polycrystalline -Si are sometimes visible on the film surface. The experimental evidence, is analysed with a view to elucidating the participation in the chemical synthesis of the three main stages of the process: the substance expulsion from the target by laser ablation, the transition through the gas of the expulsed substance and it's final impact on the collector. We conclude that silicon nitride is mostly synthesized during the impact on the collector of the flow of the ablated substance.     

Schottky barrier versus surface ferroelectric depolarization at Cu/Pb(Zr,Ti)O3 interfaces

The band bending at Cu/PZT(001) interfaces is investigated by X-ray photoelectron spectroscopy (XPS) for a PZT(001) layer which exhibits initial outwards ferroelectric polarization. Two competitive processes are identified: (a) formation of the Schottky barrier between the ferroelectric and unconnected Cu islands, and (b) coalescence of the Cu islands, realisation of an electrical contact to the ground of the system, inducing the apparent loss of the component of the ferroelectric polarization perpendicular to the sample surface, at least as it manifests in band bending. Three mechanisms are proposed to explain this loss of band bending when a full metal layer connected to ground is formed on the surface: (i) over-compensation of depolarization field in the sub-surface region, (ii) formation of domains with in-plane orientation of the polarization vector and (iii) loss of polarization in the near-surface layers of the ferroelectric due to electrons provided by the metal. These result in a non-monotonous variation of binding energies with the amount of Cu deposited. High resolution transmission electron microscopy and piezoresponse force microscopy confirmed these hypotheses. The XPS data allowed also to derive the surface PZT composition, its evolution with the deposition of copper and the formation of surface compounds.     

Drug absorption and release properties of crosslinked hydrogels based on diepoxy-terminated poly(ethylene glycol)s and aliphatic polyamines — a study on the effect of the gel molecular structure

Crosslinked hydrogels with well-defined chemical structures and characteristics were prepared through the reaction between diepoxy-terminated poly(ethylene glycol)s of various molecular weights and aliphatic polyamines of different hydrocarbon chain length and functionalities, and the influence of some network parameters (molecular weight between crosslinking points, crosslinking degree, hydrophobic character) upon the absorption and release of drugs of different capacity to interact with the polymer chains was comparatively investigated. Diclofenac sodium (DCFNa) and 5-fluorouracil (5FU) were used as model drugs, based on their dissimilar hydrophobic character and ability of DCFNa to form crown ether-like complexes with PEG chains through the sodium cation. The experiments showed that the most important interactions occurring in these systems were mainly the hydrophobic ones and to a lesser extent the complexation of the Na⁺ ion by the PEG chains. Both of them were in favor of DCFNa, resulting in a larger incorporation and a slower release of this one in comparison with 5FU. For both drugs, loading was larger for hydrogels with shorter PEG chains and/or crosslinked with amines with longer hydrocarbon chain or higher functionality. Drug release tests showed a lower rate for stronger drug–network interactions in agreement with the absorption experiments.     

Measurements of Heat Capacity of Pure Titanium and Zirconium by Electromagnetic Levitation

The heat capacity of titanium and zirconium was measured in the temperature range from approximately 1,300 K to 1,800 K . The measurement technique is based on the modulated power method originally proposed by Fecht and Johnson. The heat capacity of a sample can be derived from the sample’s temperature response to the modulated electromagnetic heating power if the sample’s total hemispherical emissivity is known. The experiments were performed using an electromagnetic levitator. The solid titanium and zirconium samples were suspended in the center of an induction coil with a very small diameter (0.15 mm) Pt (87 %)-Rh (13 %) wire. The heat capacity measurements of titanium and zirconium are presented, and the uncertainty is estimated to be ±3 %.     

X-ray absorption fine structure investigations on heat-treated Cr-doped titania thin films

Chromium-doped titanium oxide thin films were investigated in the as-deposited state and after thermal treatment (723 K for 3 h in air). X-ray diffraction data revealed an improvement in film crystallinity induced by the thermal treatment. Extended X-ray absorption fine structure data revealed similar atomic neighboring around Cr atoms in both as-deposited and annealed samples. A lattice contraction of ~ 2% is observed in the annealed samples. The 67% enhancement of the amplitude of the Cr 1 s X-ray absorption fine structure pre-edge peak after thermal treatment, which is a sign of “dipole-forbidden” 1 s → 3 d transitions, suggests strong alteration in the number of Cr 3 d vacancies, in spite of similar Cr local environment in the two kinds of investigated samples. We discuss here the Cr⁺ → Cr⁴⁺ and Cr²⁺ → Cr⁶⁺ changes induced by thermal treatment, and/or the evolution in local structures without inversion center.Refractive index dispersion spectra in the visible wavelength domain allowed us to compute the values of the dispersion energy, the single-oscillator energy and the coordination number of Ti atoms in both as-deposited and annealed samples.     

Too much of a good thing: Curvilinear relationships between personality traits and job performance.

The relationships between personality traits and performance are often assumed to be linear. This assumption has been challenged conceptually and empirically, but results to date have been inconclusive. In the current study, we took a theory-driven approach in systematically addressing this issue. Results based on two different samples generally supported our expectations of the curvilinear relationships between personality traits, including Conscientiousness and Emotional Stability, and job performance dimensions, including task performance, organizational citizenship behavior, and counterproductive work behaviors. We also hypothesized and found that job complexity moderated the curvilinear personality–performance relationships such that the inflection points after which the relationships disappear were lower for low-complexity jobs than they were for high-complexity jobs. This finding suggests that high levels of the two personality traits examined are more beneficial for performance in high- than low-complexity jobs. We conclude by discussing the implications of these findings for the use of personality in personnel selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)