Search

Juliana Bittencourt,1–4 Bruna Velasques,1–3,5 Silmar Teixeira,1,2,4 Luis F Basile,6,7 José Inácio Salles,5,8 Antonio Egídio Nardi,9 Henning Budde,10 Mauricio Cagy,11 Roberto Piedade,1 Pedro Ribeiro1,2,12 1Brain Mapping and Sensory Motor Integration Laboratory, Institute of Psychiatry, Federal University of Rio de Janeiro, 2Institute of Applied Neuroscience, Rio de Janeiro, 3Neurophysiology and Neuropsychology of Attention, Institute of Psychiatry, Federal University of Rio de Janeiro, Rio de Janeiro, 4Laboratory of Physical Therapy, Veiga de Almeida University, Rio de Janeiro, 5Neuromuscular Research Laboratory, National Institute of Traumatology and Orthopaedics, Rio de Janeiro, 6Division of Neurosurgery, University of São Paulo Medical School, São Paulo, 7Laboratory of Psychophysiology, Department of Psychology and Phonoaudiology, Universidade Metodista do Estado de São Paulo (UMESP), São Paulo, 8Brazilian Volleyball Confederation, Rio de Janeiro, 9Panic and Respiration Laboratory, Federal University of Rio de Janeiro, Instituto Nacional de Ciência e Tecnologia (INCT) e Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Rio de Janeiro, Brazil; 10Department of Sport Science and Physical Education, School of Science and Engineering, Reykjavik University, Reykjavik, Iceland; 11Biomedical Engineering Program, Coordenação dos Programas de Pós-Graduação em Engenharia (COPPE), Federal University of Rio de Janeiro, Rio de Janeiro; 12School of Physical Education, Bioscience Department Escola de Educação Física e Desportos da Universidade Federal do Rio de Janeiro (EEFD/UFRJ), Rio de Janeiro, Brazil Objective: The study presented here analyzed the patterns of relationship between oculomotor performance and psychopathology, focusing on depression, bipolar disorder, schizophrenia, attention-deficit hyperactivity disorder, and anxiety disorder. Methods: Scientific articles published from 1967 to 2013 in the PubMed/Medline, ISI Web of Knowledge, Cochrane, and SciELO databases were reviewed. Results: Saccadic eye movement appears to be heavily involved in psychiatric diseases covered in this review via a direct mechanism. The changes seen in the execution of eye movement tasks in patients with psychopathologies of various studies confirm that eye movement is associated with the cognitive and motor system. Conclusion: Saccadic eye movement changes appear to be heavily involved in the psychiatric disorders covered in this review and may be considered a possible marker of some disorders. The few existing studies that approach the topic demonstrate a need to improve the experimental paradigms, as well as the methods of analysis. Most of them report behavioral variables (latency/reaction time), though electrophysiological measures are absent. Keywords: depression, bipolar disorder, attention-deficit hyperactivity disorder, schizophrenia, anxiety disorder

We describe a technique termed resisted inspiration that could be used during myelography to decrease superior vena cava venous pressure and increase lumbar CSF pressure, potentially aiding in the detection of CSF-venous fistulas.

The ceramic Sr(NiNb)0.5O3, incorporating silver doping in the A site, was synthesized using a sol–gel route and subjected to comprehensive analysis through various experimental techniques. X-ray diffraction data analysis indicates a rhombohedral crystal structure. Scanning electron microscopy (SEM) examination reveals densely packed grains with minimal surface porosity. A thorough investigation of electrical properties, encompassing dielectric constant, loss tangent, electrical impedance, modulus, conductivity, etc., was conducted across a wide frequency range (103–106 Hz) and temperature range (260–340 K). This analysis provided valuable insights into structure–property relationships and conduction mechanisms. The discussion highlights the significance of interface effects, space charge polarization, and Maxwell–Wagner dielectric relaxation in achieving the material's high dielectric constant at low frequencies and elevated temperatures. Examination of temperature dependence through Nyquist plots elucidates the contributions of grain behavior to the material's resistive and capacitive properties. The dielectric permittivity, dissipation of energy, and electrical characteristics like impedance, modulus and conductivity are notably influenced by the frequency of the applied electric field and temperature. Overall, the material exhibits promising potential for industrial applications such as energy storage, given its intriguing properties. [ABSTRACT FROM AUTHOR]

This paper discusses the structural, microstructure and electrical properties of perovskite oxide lanthanum nickel LaNiO3, synthesized by the sol–gel reaction technique that was investigated. The prepared material was doped with bismuth and niobium and studied their properties. The Rietveld refinement of the X-ray diffraction pattern suggests that the compound has a monoclinic phase at room temperature with a P21/n space group. Scanning electron microscopy surface morphology analysis of the sample showed closed packing of grains with good density and very little porosity. The frequency-dependent modulus of the material is investigated in the temperature range from 200 K to 360 K and in range frequency between 1 kHz and 1 MHz. The Cole–Cole model is used to analyze the dielectric relaxation phenomenon. The complex impedance data are analyzed by an electrical equivalent circuit consisting of a resistance and a constant phase element, where the ideal capacitance part is replaced by a constant phase element. The frequency-dependent conductivity spectra follow the Jonscher power law. Nevertheless, the Arrhenius-type conduction mechanism was found to be active in the sample with activation energy of 0.168 eV. The electrical property of the sample was found to be independent of temperatures, making it a potential candidate for thermally stable capacitor application. [ABSTRACT FROM AUTHOR]

This study presents the dielectric properties of a barium titanate–gadolinium ferrite composite material, obtained through a solid-state reaction method. The aim of this research was to create a composite material with enhanced dielectric properties compared to each individual component, and to investigate the electrical properties of the composites, using impedance spectroscopy. The structural and morphologic properties were analyzed using X-ray diffraction and scanning electron microscopy, respectively. Impedance spectroscopy measurements were performed over a wide frequency range (100–0.1 GHz) and temperature (45–170 °C) to evaluate the electrical behavior of the material. The dielectric relaxations were analyzed using the Havriliak–Negami function, and the key electrical parameters such as relaxation frequency, dielectric strength, and electrical conductivity were extracted. Several relaxation processes were identified, which depend on the mixture of the initial titanate and ferrite materials, and a correlation between structural, morphologic, and electrical properties was exposed. The sample with the highest dielectric constant was the 25 wt% gadolinium ferrite composite, with ε′ close to 240 and loss tangent values below 0.1, affording it the more appropriate composition for energy storage devices such as lead-free dielectric capacitors. [ABSTRACT FROM AUTHOR]