551 research outputs found

    Dissociative symptoms in female patients with mood and anxiety disorders: a psychopathological and temperamental investigation.

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    Abstract OBJECTIVE: Dissociative symptoms are frequent among psychiatric patients and may considerably affect patients' psychopathological condition and treatment outcomes. The objectives of the study are to assess the presence of dissociative symptoms in female patients with mood and anxiety disorders, to investigate their correlation with the clinical severity of the disorders and to investigate those personality traits that are more frequent in patients with high levels of dissociation. PATIENTS AND METHODS: 50 Caucasian females were enrolled in the study. Patients were assessed through the Self-Report Symptom Check-List, the Dissociative Experiences Scale (DES) and rating scales for Depression and Anxiety. RESULTS: The mean DES score in the overall sample was 16.6. 32% of patients had a DES score > 20. Depressive symptoms positively correlated with the DES total scores. Dissociator patients presented some significantly different temperamental characteristics in comparison with non dissociator patients. CONCLUSIONS: Dissociative symptoms are highly present in patients with mood and anxiety disorders and correlate with the severity of depressive symptoms. Specific personality traits more frequently observed in dissociator people may represent predisposing factors; their early identification could be clinically relevant

    Calcium-gated calcium channels in sarcoplasmic reticulum of rabbit skinned skeletal muscle fibers

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    The action of ruthenium red (RR) on Ca2+ loading by and Ca2+ release from the sarcoplasmic reticulum (SR) of chemically skinned skeletal muscle fibers of the rabbit was investigated. Ca2+ loading, in the presence of the precipitating anion pyrophosphate, was monitored by a light-scattering method. Ca2+ release was indirectly measured by following tension development evoked by caffeine. Stimulation of the Ca2+ loading rate by 5 microM RR was dependent on free Ca2+, being maximal at pCa 5.56. Isometric force development induced by 5 mM caffeine was reversibly antagonized by RR. IC50 for the rate of tension rise was 0.5 microM; that for the extent of tension was 4 microM. RR slightly shifted the steady state isometric force/pCa curve toward lower pCa values. At 5 microM RR, the pCa required for half-maximal force was 0.2 log units lower than that of the control, and maximal force was depressed by approximately 16%. These results suggest that RR inhibited Ca2+ release from the SR and stimulated Ca2+ loading into the SR by closing Ca2+-gated Ca2+ channels. Previous studies on isolated SR have indicated the selective presence of such channels in junctional terminal cisternae

    Cathodoluminescence Study of Defects in III-V Substrates and Structures

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    Solid state detector cathodoluminescence studies of semiconducting and semi-insulating GaAs and InP crystals, were performed. The origin of the dislocation contrast in GaAs:Si doped substrates, in the carrier concentration range from 1016 to 6 · 1018 cm-3, were discussed. The image contrast was explained on the basis of the emission efficiency versus carrier concentration curve, obtained in the transmission mode. Single dislocations and dislocation arrangements in addition to growth striations, clusters and precipitate-like microdefects were evidenced. The above mentioned microdefects were detected in GaAs: Te, S and Si doped and InP: Sn doped specimens. Commercial InP:Sn and S doped crystals by different manufacturers were also tested in order to perform a comprehensive evaluation of the defect content. Finally, combining emission and transmission cathodoluminescence, Si and Ge detectors at different beam energies, the defect distribution of different layers in simple and double heterostructures was determined in a non-destructive way. MBE InGaAs/InP and LPE InGaAsP/InP structures, employed as semiconductor detectors and lasers, were investigated

    Cathodoluminescence, Raman and scanning electron microscopy with energy dispersion system mapping to unravel the mineralogy and texture of an altered Ca-Al-rich inclusion in Renazzo CR2 carbonaceous chondrite

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    An altered fluffy type A Ca-Al-rich inclusion in the CR2 Renazzo carbonaceous chondrite was examined by combined Raman, scanning electron microscopy with energy dispersion system (SEM-EDS) and cathodoluminescence (CL) mapping. Blue CL at 450 nm and orange emission at 600 nm were related to anorthite and calcite, respectively. Raman spectra were highly fluorescent, and only the stronger peaks of anorthite, clinopyroxene and calcite were observed. Raman-induced fluorescence emission was measured using the 632-nm Raman laser source, up to 850 nm, and used to chart the mineral phases. A fluorescence structured peak at 690 nm, split in three subpeaks at 678, 689 and 693 nm, was found; it is likely related to the fluorescence emission of Cr3+ from a fassaitic pyroxene in anorthite. Secondary pyroxene in the Wark–Lovering rim does not show the peak at 690 nm; the different fluorescence emission from the secondary rim and the pyroxene patches within anorthite could be a marker to spot the primary pyroxene. From combined imaging, the events in the altered chondrite could be sequenced. Starting from a pristine assemblage of spinel and melilite, with little fassaite, several alteration episodes occurred. Alteration in secondary anorthite, which could be mapped by the blue CL emission at 450 nm, was followed by alkalization, with rims of sodalite and nepheline, and subsequent formation of secondary clinopyroxene, encircling the inclusion. Widespread calcite alteration, present also in the matrix between chondrules, was the last recorded event

    CFD Modeling of a Laboratory-Scale Setup for Thermochemical Materials Performance Analysis

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    The search for energy saving is nowadays mandatory because of the constant growth of CO2 emissions caused by an inefficient energy management. Thermal Energy Storage (TES) has an important role in designing of energy efficient systems, including solar energy storage (daily or seasonal) and waste heat from industrial batch processes. Different solutions are possible for thermal storage, based on sensible heat (e.g. water tanks), latent heat (phase change materials) or reaction enthalpy (thermochemical systems). In Thermochemical TES, a material is chosen so that it shows a high-enthalpy reversible chemical reaction at a desired temperature. In particular, water sorption in some inorganic salt hydrates is pointed out as one of the most suitable reactions for low temperature energy storage (60-120 °C). The reaction products, water and salt in a less hydrated form, are kept separated and consequently the heat is stored. Energy release is obtained with salt hydration. The main advantages are an energy storage capacity higher than other TES technologies and the possibility to control the energy release. On the other hand, one of the main issues is the difficulty to test materials performance, because standard characterization techniques use small amount of samples and their properties change dramatically when the system is scaled up to large reactors. The aim of this work is to realize a laboratory scale setup to test the performance of salt hydrate composites. A scheme of the system is reported in the attached figure (above). The active material is kept in an evaporator at a temperature sufficient to generate the dehydration reaction. Extracted water mass is measured in time in a condenser at 0°C. Air flow, temperature and humidity are measured with sensors in the system. The system was simulated using COMSOL® software. In particular the simulation was inspired by two models from the Application Library, Degradation of DNA in Plasma and Protein Adsorption. At first, a zero dimensional component was created with the Reaction Engineering module with two reactions to evaluate both the dehydration and condensation steps: H2Ocry->H2Ovap H2Ovap->H2Oliq Where H2Ocry is the crystallization water in the salt hydrate, H2Ovap is the air humidity and H2Oliq is the condensed water. Using a Parameter Estimation module, experimental data about dehydration were imported in the software and used to estimate the reactions kinetics constants. After that, using a Generate Space Dependent Model module we obtained a 3D component with a realistic system geometry (see attached figure below) including the modules Chemistry, Transport of Diluted Species, Surface Reactions, Heat transfer in Fluids and Single Phase Laminar Flow. Rate constants calculated in the zero-dimension model were used as first guess for the 3D model reactions. We verified that the model is able to evaluate temperature, flow and water concentration as well as the evolution of the two reactions in time. We expect that this model will allow us to classify different Thermochemical TES materials about their efficiency in heat and mass exchange, as well as to refine the design of the thermal storage system

    Growth of graphitic carbon layers around silicon carbide nanowires

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    © 2019 Author(s). We demonstrate the ability to synthesize graphitic carbon sheets around cubic silicon carbide nanowires via an alloy-mediated catalytic process. The transmission electron microscopy analysis shows multilayer graphitic carbon sheets with a large interatomic layer distance of ∼0.45 nm, suggesting the presence of oxygen in the graphitic system. Oxygen-related peaks observed by energy-dispersive X-ray spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy further confirm the oxidation of the graphitic carbon layers. A detailed investigation of the Raman spectra reveals a turbostratic stacking of the graphitic carbon layers. The turbostratic nature and the presence of oxidation in the graphitic carbon surrounding the silicon carbide nanowires make them a suitable platform for further functionalization, of particular interest for biosensing, as both graphitic carbon and silicon carbide are biocompatible

    InAs/InP/InSb Nanowires as Low Capacitance n-n Heterojunction Diodes

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    Nanowire diodes have been realized by employing an axial heterojunction between InAs and InSb semiconductor materials. The broken-gap band alignment (type III) leads to a strong rectification effect when the current-voltage (I-V) characteristic is inspected at room temperature. The additional insertion of a narrow InP barrier reduces the thermionic contribution, which results in a net decrease of leakage current in the reverse bias with a corresponding enhanced rectification in terms of asymmetry in the I-V characteristics. The investigated diodes compare favorably with the ones realized with p-n heterostructured nanowires, making InAs/InP/InSb devices appealing candidates to be used as building blocks for nanowire-based ultrafast electronics and for the realization of photodetectors in the THz spectral range
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