252 research outputs found
Angular dependence of the bulk nucleation field Hc2 of aligned MgB2 crystallites
Studies on the new MgB2 superconductor, with a critical temperature Tc ~ 39
K, have evidenced its potential for applications although intense magnetic
relaxation effects limit the critical current density, Jc, at high magnetic
fields. This means that effective pinning centers must be added into the
material microstructure, in order to halt dissipative flux movements.
Concerning the basic microscopic mechanism to explain the superconductivity in
MgB2, several experimental and theoretical works have pointed to the relevance
of a phonon-mediated interaction, in the framework of the BCS theory. Questions
have been raised about the relevant phonon modes, and the gap and Fermi surface
anisotropies, in an effort to interpret spectroscopic and thermal data that
give values between 2.4 and 4.5 for the gap energy ratio. Preliminary results
on the anisotropy of Hc2 have shown a ratio, between the in-plane and
perpendicular directions, around 1.7 for aligned MgB2 crystallites and 1.8 for
epitaxial thin films. Here we show a study on the angular dependence of Hc2
pointing to a Fermi velocity anisotropy around 2.5. This anisotropy certainly
implies the use of texturization techniques to optimize Jc in MgB2 wires and
other polycrystalline components.Comment: 10 pages + 4 Figs.; Revised version accepted in Phys. Rev.
Factors associated with adherence to immunomodulator treatment in people with multiple sclerosis
Abstract To determine the association between factors and adherence to immunomodulator treatment in people with multiple sclerosis treated in reference centers. Cross-sectional study conducted with 188 people who used immunomodulators in three reference centers in Ceará from March to July 2012. Adherence was assessed using the Moriskscale and factors were assessed using a questionnaire addressing socioeconomic and personal characteristics, the disease, the use of immunomodulator and educational activities. The determination of the association was expressed in crude and adjusted odds ratio with a 95% confidence interval. Adherence rate was 46% and after the logistic regression model the adherence to immunomodulator treatment was positively associated with the following factors: age 18-38 years, time of diagnosis and treatment between 6 and 24 months, 0-3.5 score in the Expanded Disability Status Scale, perception of treatment benefits, intrinsic and extrinsic motivation, phone contact with the doctor and not missing the return visit. This study is important because it allowed to determine the association between factors and adherence to immunomodulator treatment in multiple sclerosis, contributing to prevention and control actions
The Milky Way Bulge: Observed properties and a comparison to external galaxies
The Milky Way bulge offers a unique opportunity to investigate in detail the
role that different processes such as dynamical instabilities, hierarchical
merging, and dissipational collapse may have played in the history of the
Galaxy formation and evolution based on its resolved stellar population
properties. Large observation programmes and surveys of the bulge are providing
for the first time a look into the global view of the Milky Way bulge that can
be compared with the bulges of other galaxies, and be used as a template for
detailed comparison with models. The Milky Way has been shown to have a
box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an
additional spheroidal component. In this review we summarise the global
chemical abundances, kinematics and structural properties that allow us to
disentangle these multiple components and provide constraints to understand
their origin. The investigation of both detailed and global properties of the
bulge now provide us with the opportunity to characterise the bulge as observed
in models, and to place the mixed component bulge scenario in the general
context of external galaxies. When writing this review, we considered the
perspectives of researchers working with the Milky Way and researchers working
with external galaxies. It is an attempt to approach both communities for a
fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen
E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure
Glicemia e concentrações sĂ©ricas de insulina, triglicĂ©rides e cortisol em equinos da raça Mangalarga Marchador apĂłs exercĂcio fĂsico
O presente estudo teve por objetivo avaliar a influĂŞncia do exercĂcio fĂsico de intensidade submáxima (provas de marcha) sobre as variáveis bioquĂmicas sanguĂneas usadas na avaliação do metabolismo energĂ©tico em equinos da raça Mangalarga Marchador criados no Estado do EspĂrito Santo. Para tal foram obtidas amostras de soro e plasma de 15 equinos, da raça Mangalarga Marchador, em quatro momentos assim definidos: antes (T0) e com 5 minutos (T1), 30 minutos (T2) e 2 horas (T3) apĂłs o tĂ©rmino do exercĂcio. A análise dos resultados demonstrou a nĂŁo influĂŞncia do exercĂcio fĂsico imposto sobre a glicose plasmática, com valores mĂ©dios de 117,1±35,8mg/dL, 122,6±59,6mg/dL, 124,8± 48,6mg/dL e 112,9±49,1mg/dL, e sobre a insulina sĂ©rica, com valores de mediana de 6,50mUI/mL, 2,00mUI/mL, 5,85mUI/mL e 11,60mUI/mL, respectivamente, nos tempos T0, T1, T2 e T3. De forma oposta, foi possĂvel observar uma influĂŞncia significativa sobre triglicĂ©rides sĂ©ricos, com valores mĂ©dios de 25,4±14,9mg/dL, 42,3±17,8mg/dL, 31,4±17,7mg/dL e 25,1±15,1mg/dL, e sobre o cortisol sĂ©rico, com valores mĂ©dios de 7,46±4,37mg/dL, 12,45±3,08mg/dL, 11,40±2,52mg/dL e 6,89±1,78mg/dL, respectivamente nos tempos T0, T1, T2 e T3. A interpretação destes resultados permitiu concluir que a marcha elevou as concentrações sĂ©ricas de triglicĂ©rides e cortisol. TambĂ©m foi possĂvel destacar que, por tais valores encontrarem-se dentro de intervalos fisiolĂłgicos, os equinos usados estavam aptos ao nĂvel de exercĂcio fĂsico imposto na ocasiĂŁo
Synthesis and in-vitro cytotoxicity analysis of microwave irradiated nano-apatites
NOTICE: this is the author’s version of a work that was accepted for publication in Ceramics International. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in CERAMICS INTERNATIONAL, [VOL 39, ISSUE 4, (2013)] DOI 10.1016/j.ceramint.2012.11.017Nano-sized calcium deficient apatite (CDA) micelles were synthesized through microwave assisted the wet precipitation technique. Cetyltrimethylammonium bromide (CTAB) was employed as surface template to furnish the CDA particles with tailored size and shape. As-precipitated CDA was heat treated to observe the effect of heat treatment temperature on the interatomic rearrangement of entities within the apatite lattice. This transformation is responsible for conversion of CDA to β-tricalcium phosphate (β-TCP) at specific temperature. The phase purity, particles size, morphology and transformation kinetics were analyzed using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA). In-vitro studies were performed on β-TCP with three cell lines: osteoblasts, HeLa, and SF 767. The results showed that nano-sized particles were successfully synthesized in short time. The cells had appreciable proliferation/attachment on the surface of these nano-particles. It is concluded that the microwave irradiated synthesized β-TCP has good capacity in terms of biocompatibility and has the potential to be used in hard tissue regeneration applications.Nano-sized calcium deficient apatite (CDA) micelles were synthesized through microwave assisted the wet precipitation technique. Cetyltrimethylammonium bromide (CTAB) was employed as surface template to furnish the CDA particles with tailored size and shape. As-precipitated CDA was heat treated to observe the effect of heat treatment temperature on the interatomic rearrangement of entities within the apatite lattice. This transformation is responsible for conversion of CDA to β-tricalcium phosphate (β-TCP) at specific temperature. The phase purity, particles size, morphology and transformation kinetics were analyzed using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA). In-vitro studies were performed on β-TCP with three cell lines: osteoblasts, HeLa, and SF 767. The results showed that nano-sized particles were successfully synthesized in short time. The cells had appreciable proliferation/attachment on the surface of these nano-particles. It is concluded that the microwave irradiated synthesized β-TCP has good capacity in terms of biocompatibility and has the potential to be used in hard tissue regeneration applications
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