Caracterização molecular do Cão Barbado da Terceira

Dissertação de Mestrado em Engenharia Zootécnica.Neste trabalho analisaram-se 257 animais da raça Cão Barbado da Terceira sendo caracterizados geneticamente, por doze microssatélites identificando-se um total de 79 alelos. A variabilidade genética foi estimada através das frequências alélicas, diversidade genética, heterozigocidade esperada e observada, probabilidade de identidade e verificação do equilíbrio de Hardy-Weinberg. Analisou-se as distâncias genéticas entre grupos pré-definidos consoante o ano de nascimento. Realizaram-se testes de paternidade comparando com os dados cedidos pelos criadores dos animais em questão, com bons resultados confirmando-se a compatibilidade com os progenitores na maioria dos casos. A população continua a manter variabilidade genética suficiente para não sofrer um processo de inbreeding, contudo deve ser dada atenção aos reprodutores a serem utilizados no futuro de forma a se conseguir uma maior heterozigocidade na raça para que haja uma evolução positiva da mesma. Desta forma os objectivos deste trabalho foram conseguidos, sendo este tipo de marcadores moleculares suficientemente informativos para esta caracterização.ABSTRACT: In this study 257 animals from the Cão Barbado da Terceira breed were analyzed, which were genetically characterized with twelve microsatellites, with a total of 79 alleles identified. The genetic variability was estimated through the allelic frequencies, genetic diversity, expected and observed heterozygosity, identity probability and verification of the Hardy-Weinberg equilibrium. There was also the analysis of the genetic distances between groups predefined according to the year of birth, as well as paternity tests by the comparison with the data provided by the breeders. Good results were obtained and the compatibility with the parents was confirmed in most cases. The population still maintains enough genetic variability in order not to undergo inbreeding however one should pay attention to the breeders to be used in the future, in a way to obtain a higher heterozygosity so there is a positive evolution of the breed. Therefore the aims of this study were achieved, and this type of molecular markers was sufficiently informative for this characterization

The Influence of Thermomechanical Treatments on the Structure, Microstructure, and Mechanical Properties of Ti-5Mn-Mo Alloys

With the increase in the world’s population, the rising number of traffic accidents, and the increase in life expectancy, the need for implants, dental work, and orthopedics is growing ever larger. Researchers are working to improve the biomaterials used for these purposes, improve their functionality, and increase the human body’s life span. Thus, new titanium alloys are being developed, usually with β-stabilizer elements (which decrease the elastic modulus), with the Ti-Mn-Mo alloys being one example of these. This study of the Ti-5Mn-10Mo and Ti-5Mn-15Mo alloys only showed signs of the β phase in the structure and microstructure, presenting a combination of low modulus of elasticity and high corrosion resistance compared to the values of commercial alloys. In this sense, this work presents an analysis of the influence of some thermomechanical treatments, such as homogenization, hot-rolling, solution, and annealing, on the structure, microstructure, and selected mechanical properties of the Ti-5Mn-10Mo and Ti-5Mn-15Mo alloys

Synthesis, optical and ferroelectric properties of PZT thin films: experimental and theoretical investigation

PbZr0.40Ti0.60O3 (PZT40/60) thin films with ferroelectric and dielectric properties have been grown on Pt/Ti/SiO2/Si and LaAlO3 (100) substrates using the chemical solution deposition method. These films have been characterized by different techniques such as X-ray diffraction (XRD), Raman, infrared and optical transmittance measurements. The transmittance curve of the PZT40/60 thin films on a LaAlO3 (100) substrate showed an optical band gap of 4.03 and 3.10 eV for the direct and indirect transition processes, respectively. To complement experimental data, first principles calculations at the DFT-B3LYP level were performed on periodic model systems of PbTiO3 and PZT40/60 to provide an insight into structural, optical and electronic behavior. The band gap of the PZT40/60 system for PbO and ZrO2 terminations is in agreement with trends of experimental data and results in smaller values than the band gap calculated for the PbTiO3 system.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Effect of Titanium Addition on the Structure, Microstructure, and Selected Mechanical Properties of As-Cast Zr-25Ta-xTi Alloys

Ti alloys are the most used metallic materials in the biomedical field due to their excellent biocompatibility associated with good corrosion resistance in body fluids and relatively low elastic modulus. However, the alloys used in the orthopedic area have an elastic modulus that is 2 to 4 times higher than that of human cortical bone. Searching for new alloys for biomedical applications and with low elastic modulus, zirconium gained prominence due to its attractive properties, especially its biocompatibility. The purpose of this paper is to present novel as-cast alloys of the Zr-25Ta-xTi system and analyze the influence of titanium on the structure, microstructure, microhardness, and elastic modulus of the alloys. The alloys were prepared using an arc-melting furnace. X-ray diffraction measurements and microscopy techniques were used to characterize the crystalline structure and microstructure. From structural and microstructural characterizations, it was observed that titanium acted as an α-stabilizing element since its increase in the precipitation of the orthorhombic α” phase, an intermediate phase from β to α phases, in the alloys. Regarding microhardness measurements, the alloys have higher hardness than pure zirconium due to solid solution hardening that detaches the Zr-25Ta alloy, which has a high hardness value of the precipitation of the ω phase. Among the studied alloys, the Zr-25Ta-25Ti alloy is highlighted, demonstrating the lowest result of modulus of elasticity, which is approximately 2 times higher than the human cortical bone, but many alloys used in the biomedical field, such as pure titanium, have elastic modulus values almost 3 times higher than that of human bone

Improvement of electrical properties of Sr-modified (Pb,Ca)TiO3 thin films grown by soft chemistry route

Strontium and calcium-modified lead titanate (Pb0.70Ca0.15Sr0.15)TiO3 soft chemistry-derived thin films were prepared on platinum-coated silicon substrate by spin-coating method. Investigations were made on the structure, surface morphology and electrical properties of the film. The results by XRD and FE-SEM showed that the film exhibits a pure tetragonal perovskite phase and an average grain size of about 50-60 nm, respectively. Electrical measurements of a metal-ferroelectric-metal type capacitor exhibited a stable and switchable electrical polarization in the film. The structure of the Au/PCST/Pt capacitor showed well-saturated hysteresis loops at an applied voltage of 300 kV/cm with remanent polarization and coercive field values of 22 mu C/cm(2) and 100 kV/cm, respectively. At 100 kHz, the dielectric constant and the dielectric loss of the (Pb0.70Ca0.15Sr0.15)TiO3 thin film with thickness 240 nm were 528 and 0.05, respectively. (C) 2008 Elsevier Ltd. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Tunable visible photoluminescence of powdered silica glass

intense photoluminescence in the visible region was observed at room temperature in standard soda-lime-silica glass powder, mechanically milled in a high-energy attrition mill. The emission band maximum shows an interesting dependence on the exciting wavelength, suggesting the possibility to tune the PL emission. These findings indicate that the photoluminescence may be directly related to unsatisfied chemical bonds correlated with the high surface area. The Raman scattering and ultraviolet-visible optical reflectance measurements corroborate this assertion. Transmission electron microscopy measurements indicate that samples milled more than 10 h present the formation of nanocrystallites with about 10-20 nm. (C) 2007 Elsevier B.V. All rights reserved

Effect of strontium addition on ferroelectric phase transition of PZT thin films prepared by chemical route

The dependence of ferroelectric phase transition temperature as a function of strontium substitution in lead titanate zirconate thin films (referred here as PSZT) on platinum-coated silicon substrates was investigated. The dielectric study reveals that the material undergoes a diffuse type ferroelectric phase transition that depends on the substitution of Sr for Pb in PZT. At 100 kHz, the phase transition temperatures were 633, 613 and 516 K for PSZT10, PSZT20 and PSZT30 thin films, respectively. on the other hand, the results showed that the dependence of the dielectric constant upon the frequency does not reveal any relaxor behavior. The diffusivity increases with increasing Sr contents in the studied composition range. The experimental data obtained from measurements of the dielectric constant as a function of temperature and frequencies showed a classical behavior of ferroelectric phase transition in PSZT thin films, rather than a relaxor ferroelectric phase transition. The transition temperature decreases with increasing Sr contents due to the decrease in grain size, lattice decrease and local structural disorder.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Structural and morphological characterization of Pb1-xBaxTiO3 thin films prepared by chemical route: An investigation of phase transition

Detailed room temperature micro-Raman scattering, X-ray diffraction, atomic force microscopy and specular reflectance infrared Fourier transform spectroscopy studies were carried out on soft chemical by processed Pb1-xBaxTiO3 thin films. The micro-Raman spectra pointed the existence of a stable tetragonal ferroelectric phase in the entire composition range (0 < x <= 1). The infrared reflectance spectra showed that the frequency of several peaks decreases as the Ba2+ concentration increases. These features are correlated to a decrease in the tetragonal distortion of the TiO6 octahedra as the Ba2+ concentration increases. Furthermore, as x increases from 0.70 to 1.0, the Raman spectrum shows an evolution towards the well-known Raman spectrum of the tetragonal BaTiO3. Therefore, we demonstrated that the combination of solid solution PbTiO3-BaTiO3 with a grain size in the order of 30-40 nm supports the tetragonal ferroelectric phase at room temperature. (C) 2007 Elsevier B.V. All rights reserved

Polymeric precursor method to the synthesis of XWO(4) (X = Ca and Sr) thin films-Structural, microstructural and spectroscopic investigations

Stoichiometric XWO(4) (X = Ca, and Sr) thin films were synthesized using the polymeric precursor method. In this soft chemical method, soluble precursors such as strontium carbonate, calcium carbonate and tungstic acid, as starting materials, were mixed in an aqueous solution. Through the polyesterification reaction, evidences of the formation of the W-citrate complex and the strontium were obtained by (13)C NMR and FT-Raman spectroscopy. The thin films were deposited on silicon and platinum-coated silicon substrates through the spinning technique. The surface morphology and crystal structure of the thin films were investigated using atomic force microscopy (AFM), X-ray diffraction (XRD), specular reflectance infrared Fourier transform spectroscopy, and micro-Raman spectroscopy. Nucleation stages and surface morphology evolution of the thin films on silicon substrates were studied by atomic force microscopy. X-ray diffraction characterization of these films showed that the XWO(4) (X = Ca, and Sr) thin film phases crystallize at 500 degrees C from an inorganic amorphous phase, given that no intermediate crystalline phase was identified. (C) 2008 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Vibrational spectra of pilocarpine hydrochloride crystals

Pilocarpine is a natural substance with potential application in the treatment of several diseases. In this work Fourier Transform (FT)-Raman spectrum and the Fourier Transform infra red (FT-IR) spectrum of pilocarpine hydrochloride C11H17N2O2+.Cl- were investigated at 300 K. Vibrational wavenumber and wave vector have been predicted using density functional theory (B3LYP) calculations with the 6-31 G(d,p) basis set. A comparison with experiment allowed us to assign most of the normal modes of the crystal