Synthesis of Ti–Sn–Nb alloy by powder metallurgy

The microstructural evolution and characteristics of the Ti–16Sn–4Nb powder particles and bulk alloys sintered from the powders ball-milled for various periods of time were studied. Results indicated that ball milling to 8 h led to the development of a supersaturated hcp α-Ti and partial amorphous phase due to the solid solution of Sn and Nb into Ti lattice. The bulk Ti–16Sn–4Nb alloy made from the powders ball milled for a short time, up to 2 h, exhibited a primary α and a Widmanstätten structure consisting of interlaced secondary α and β. With an increase in ball milling time up to 10 h, the microstructure evolved into a fine β phase dispersed homogeneously within α phase matrix. The microhardness values of the bulk alloy in both α- and β-phases increased with the increasing of the ball milling time and reached a plateau value at 8 h and longer, i.e. 687 and 550 HV for α- and β-phases, respectively. Likewise, the microhardness of the α phases was always higher than that of the β phases in the bulk alloys made from the powders ball milled for the same milling time.

Pilot Study of clinician attitudes to insulin pump therapy: international differences and the need for a greater understanding of the patient perspective

OBJECTIVES: To identify and survey health care professionals (HCPs) attitudes to insulin pump therapy (CSII).

METHODS: Eight specialists were interviewed to explore the attitudes and beliefs about CSII. Responses were analysed thematically and used to inform the design of a new 22-item questionnaire: the Attitudes to Pump Therapy (APT) Survey. The APT was pilottested among 95 HCPs (54% male; 75.5% diabetologists/DSNs, 13.8% general practitioners) at the International Diabetes Federation (IDF) conference, 2006. Results were analysed using non-parametric statistics with bonferroni correction.

RESULTS: Analyses of interview data identified 9 themes: biomedical, perceived control of care/diabetes, technology, quality of life, financial resources, training, education & support, suitability, and evidence-base. Items were designed to reflect these themes with responses scored on a 5-point Likert scale (strongly agree—strongly disagree). No statistically significant differences
were found by gender, HCP speciality, country (and continent) of origin or proportion of patients using CSII. Most notable differences were found in relation to gross domestic product (GDP) and the potential for pump therapy to achieve tight blood glucose control (lower GDP = more agreement: p = 0.001), and result in diabetic ketoacidosis (DKA) (lower GDP = less agreement: p < 0.005). Ranked mean scores showed a split between biomedical/clinical items (N = 11) and items concerned with patient experience (N = 11). Attitudes about biomedical/clinical issues were generally clear (i.e. for 7/11 items, the mean score was “agree”) but less decisive about patient experience (i.e. for 8/11 items, the mean score was “neither agree nor disagree”).

CONCLUSION: Few subgroup differences existed, but those that did may be explained by lack of access to treatment (directly corresponding to GDP). Clinicians’ were generally clear in their attitudes regarding biomedical aspects but less so regarding patient experience. Research focusing on patient-reported outcomes is likely to offer clinicians a greater understanding of the patients’ perspective of insulin pump therapy.

Effect of grain size on deformation twinning in a magnesium alloy and commercial purity titanium

This data collection contains several optical microstructure images, EBSD maps and stress-strain curves. The research involves collecting data from samples with different grain sizes at several values of plastic strains to measure some important twinning parameters such as twin volume fraction and number of twins per grain. The aim of this study is to investigate the effect of grain size on deformation twinning behaviour in two hcp metals i.e. commercial purity titanium and AZ31 magnesium alloy.

Time and spatial resolution of slip and twinning in a grain embedded within a magnesium polycrystal

Plastic yielding in magnesium alloys frequently involves the initiation of both slip and twinning events. A proper understanding of the phenomenon at the grain level requires knowledge of how these two mechanisms progress and interact over both time and space and what the local resolved stresses are. To date, simultaneous collection of such information has not been achievable. To address this shortfall, we have developed a modified Laue based in situ micro X-ray diffraction technique with an unprecedented combination of time and spatial resolution. A ten-fold reduction in data collection times is realized by the refinement of rapid polychromatic Laue "single-shot" mapping. From single Laue patterns, we extract grain depth information, detect onset of yielding and achieve 2 × 10-4 lattice strain resolution. The technique is employed to examine yielding and twinning in a magnesium grain embedded ∼200 μm below the sample surface. We examine 13 time steps and reveal the following behaviour: initial onset of basal slip, subsequent onset of twinning, development of further accommodation slip and evolution of twin shape and size; along with the corresponding values of local resolved shear stresses. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A discrete choice experiment to examine the preferences of patients with cancer and their willingness to pay for different types of health care appointments

BACKGROUND: This study sought to understand the preferences of patients with cancer and the trade-offs between appointment attributes using discrete choice experiment (DCE). METHODS AND STUDY DESIGN: Patients with cancer at 3 hospitals completed a self-administered DCE. Each scenario described 6 attributes: expertise of health care professionals (HCPs), familiarity of doctors with patients' medical history, waiting time, accompaniment by family/friends, travel time, and out-of-pocket costs. Patient preferences were estimated using logistic regression. Willingness to pay (WTP) estimates were derived from regression coefficients. RESULTS: Of 512 patients contacted, 185 returned the questionnaire. The mean age was 61 years, and 60% of respondents were female. The mean time since cancer diagnosis was 34 months, 90% had received treatment; and 61% had early-stage disease. The most important attributes were expertise and familiarity of doctors with patients' medical history; distance traveled was least likely to influence patient preferences. The WTP analysis estimated that patients were willing to pay $680 (95% CI, 470-891) for an appointment with a specialist, $571 (95% CI, 388-754) for doctors familiar with their history, $422 (95% CI, 262-582) for shorter waiting times, $399 (95% CI, 249-549) to be accompanied by family/friends, and $301 (95% CI, 162-441) for shorter traveling times. Male patients had a stronger preference for accompaniment by family/friends. The expertise of HCP was the most important attribute for patients regardless of geographic remoteness. CONCLUSIONS: Our study can assist the development of patient-centered health care models that improve patient access to experienced HCPs, support the role of primary care providers during the cancer journey, and educate patients about the roles of non-oncology HCPs to cope with increasing demand for cancer care.

Estudo da evolução estrutural induzida por irradiação iônica em multicamadas de Fe/sub 30/Co/sub 70/Cu

Neste trabalho, relata-se o comportamento estrutural de multicamadas de Fe30Co70/Cu, quando submetidas a irradiações com íons de He+ e Kr+ e tratamentos térmicos. As multicamadas foram confeccionadas à temperatura ambiente, numa câmara de ultra-alto vácuo por evaporação alternada de uma liga Fe30Co70 e Cu. As energias das irradiações foram escolhidas de tal forma que os íons atravessassem a multicamada, ficando alojados no substrato de Si. As doses foram calculadas para que os dois tipos de íons depositassem a mesma energia total na multicamada. Após a confecção dos filmes, os mesmos foram submetidos a tratamentos térmicos de 10 minutos em temperaturas variando de 350 a 450 oC. Este processo quebra a estrutura de camadas e forma uma liga heterogênea de grãos magnéticos embebidos numa matriz metálica de Cu. Para investigar a evolução das propriedades estruturais das amostras utilizou-se difração, refletividade e espectroscopia de absorção de raios-X. Os resultados da refletividade de raios-X mostraram claramente que uma estrutura de multicamadas é formada após a evaporação, fato que é comprovado pelo pico de Bragg observado nas curvas de refletividade. As irradiações com He+ e Kr+ não destroem a estrutura de multicamadas, ao contrário, elas provocam um alisamento de todas as interfaces. Pelas medidas de difração de raios-X verificou-se que as irradiações resultam no aumento de cristalinidade e no crescimento de tamanho dos cristalitos do sistema. A irradiação com He+ não provoca mudanças significativas na multicamada, mas a irradiação com Kr+ induz uma transformação de fase de bcc para fcc/hcp nas camadas de Fe30Co70. Esta nova fase induzida pela irradiação com Kr+ é metaestável, pois um simples tratamento térmico de 450 oC durante 10 minutos destrói a nova estrutura fcc/hcp, fazendo com que a liga retorne a estrutura bcc. As medidas de absorção de raios-X estão em perfeito acordo com as medidas de difração e refletividade, mostrando que as irradiações promovem uma melhora na ordem cristalográfica. De acordo com o que foi observado das medidas, a irradiação com He+ não provoca nenhum efeito significativo na estrutura da liga de FeCo. Contudo, a irradiação com Kr+ induz uma transformação de fase nesta liga de bcc para uma estrutura fcc e/ou hcp. Tal transformação é induzida pela irradiação com Kr+ porque estes íons transferem mais energia, em colisões nucleares, do que os íons de He+. Além disso, estes íons provocam um grande número de cascatas de colisões, fazendo com que os átomos contidos dentro do volume destas cascatas tornem-se móveis. Desta forma, os átomos de Fe e Co se rearranjam em uma estrutura fcc, que é imposta pelas camadas de Cu adjacentes. Embora a estrutura fcc seja muito mais provável, também é possivel que a estrutura induzida seja hcp.

Dynamical Elastic Moduli of the Ti-13Nb-13Zr biomaterial alloy by mechanical spectroscopy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis and characterization of solid 2-methoxycinnamylidenepyruvic acid

O ácido 2-metoxicinamalpirúvico (2-MeO-HCP) foi sintetizado e caracterizado por ressonância magnética nuclear (¹H and 13C NMR), espectrometria de massas (MS), espectroscopia na região do infravermelho (FTIR) e calorimetria exploratória diferencial (DSC). A técnica DSC foi usada para determinação da pureza do composto e as principais bandas de absorção na região do infravermelho foram atribuídas utilizando-se o programa GaussView 3.0.

Fermented soy product supplemented with isoflavones affected fat depots in juvenile rats

Objectives: This study investigated the effects of soy product fermented by Enterococcus faecium and Lactobacillus jugurti supplemented with isoflavones on adipose tissue, blood lipid, and glucose levels on juvenile rats. Methods: Rats were fed a cholesterol-enriched diet for 3 wk as a preliminary treatment to create hypercholesterolemia. They were then fed a chow diet (HC), a chow diet plus fermented soy product supplemented with isoflavones (HCFI), a chow diet plus placebo (HCP), or a chow diet plus placebo supplemented with isoflavones (HCPI), respectively, for an additional 3 wk. Results: The beneficial effects of fermented soy product supplemented with isoflavones on epididymal (EPI) and retroperitoneal (RET) fat pads was likely due to isoflavones because adipocyte circumference (micrometers) in the HC group was significantly larger (EPI: 105.66 ± 13.36; RET: 134.95 ± 25.40) than that in the HCFI group (EPI: 93.17 ± 12.80; RET: 108.62 ± 15.50) and HCPI group (EPI: 93.06 ± 15.10; RET: 112.34 ± 18.21). The probiotic micro-organism accentuated the antilipogenic effect of isoflavones on RET (HCFI: 108.62 ± 15.50 micrometers versus HCPI: 112.34 ± 18.21 micrometers). Moreover, the fermented product increased glucose concentration similar to that in the chow group but did not change blood lipids. Conclusion: This product may offer new approaches to obesity prevention. © 2005 Elsevier Inc. All rights reserved.

Crystallographic structure of Ti-6Al-4V, Ti-HP and Ti-CP under high-pressure

The phase stability of a commercial purity (Ti-CP), high purity (Ti-HP) and Ti-6Al-4V alloy were investigated in a diamond anvil cell up to 32 GPa and 298 K using a polychromatic X-ray beam. The Ti-CP and Ti-HP shown the same HCP (c/a∼0.632) to Hexagonal (c/a∼1.63) non reversible martensitic transition at about 9 GPa. The as received Ti-6Al-4V shows a very low relative volume fraction β-Ti / α-Ti. No phase changes were observed in the Ti-6Al-4V alloy in the pressure range of this study. The α phase of the Ti-6Al-4V shows monotonic volume cell pressure dependence. This volume change is reversible and non-hysteretic. The cell of the a phase recovered its original volume when the pressure was released. © 2010 IOP Publishing Ltd.

The effect of the solute on the structure, selected mechanical properties, and biocompatibility of Ti-Zr system alloys for dental applications

New titanium alloys have been developed with the aim of utilizing materials with better properties for application as biomaterials, and Ti-Zr system alloys are among the more promising of these. In this paper, the influence of zirconium concentrations on the structure, microstructure, and selected mechanical properties of Ti-Zr alloys is analyzed. After melting and swaging, the samples were characterized through chemical analysis, density measurements, X-ray diffraction, optical microscopy, Vickers microhardness, and elasticity modulus. In-vitro cytotoxicity tests were performed on cultured osteogenic cells. The results showed the formation essentially of the α′ phase (with hcp structure) and microhardness values greater than cp-Ti. The elasticity modulus of the alloys was sensitive to the zirconium concentrations while remaining within the range of values of conventional titanium alloys. The alloys presented no cytotoxic effects on osteoblastic cells in the studied conditions. © 2013 Elsevier B.V. All rights reserved.

Avaliação energética e ambiental de briquetes produzidos com rejeitos de resíduos sólidos urbanos e madeira de Eucalyptus grandis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anomalias eletromagnéticas de corpos tubulares inclinados em contato com o manto de intemperismo usando diferentes arranjos de bobinas-modelamento analógico

A principal aplicação dos métodos eletromagnéticos é a prospecção de sulfetos maciços que pela própria natureza geológica são corpos longos e delgados, encrustados em rocha encaixante resistiva, permitindo a interpretação através de curvas de modelos reduzidos usando semi-planos em meio resistivo (ar-livre). No entanto, com a extensão do uso dos métodos eletromagnéticos em regiões que tem um manto de intemperismo de parcialmente condutivo a condutivo, como na região Amazônica e nas regiões semi-áridas ou de climas tropicais , esta técnica de interpretação tem levado a resultados bem diferentes da situação real. O objetivo deste trabalho é estudar a influência do manto de intemperismo em contato ôhmico com o corpo-alvo, utilizando os arranjos de bobinas horizontal coplanar (HCP), vertical coplanar (VCP), vertical coaxial (VCA) e mínimo (PERP), através do modelagem analógico. Para simular o corpo foram utilizadas placas de grafite, cujas dimensões satisfazem a condição de semi-plano. Para simular o manto foi usada uma solução de cloreto de amônia. De forma geral, os resultados obtidos com os diversos arranjos apresentaram as mesmas características, ressalvada as diferenças peculiares de cada arranjo. De forma resumida tem-se as seguintes alterações na anomalia atribuídas à um manto condutivo em contato ôhmico com o corpo-alvo: i) Há rotação de fase, que inicialmente é em sentido anti-horário, mas mais adiante, com o aumento do número de indução do manto , torna-se horária; ii) Alteração na forma padrão do perfil de quadratura devido ao surgimento do pico extra no lado a favor do mergulho; iii) Só há uniformidade de comportamento para o pico-a-pico contra da quadratura, que cresce com o aumento número de indução do manto. Maiores anomalias são obtidas com o sistema horizontal coplanar e as menores com o vertical coplanar. Neste estudo não foi observado formação de pico extra nas anomalias do arranjo vertical coplanar. Ainda, os efeitos de cobertura são mais acentuados no sistema horizontal coplanar comparados aos sistemas de bobina vertical e em anomalias de semi-planos menos inclinados e em menor profundidade.

Síntese, caracterização e estudo do comportamento térmico dos 2-metoxicinamalpiruvatos de lantanídeos (III), exceto promécio, e ítrio (III) no estado sólido

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Professores dos anos iniciais do ensino fundamental, pedagogia histórico-crítica e ensino de ciências: investigando articulações

Pós-graduação em Educação para a Ciência - FC