Physical properties of single-crystalline fibers of the colossal-magnetoresistance manganite La0.7Ca0.3MnO3

We have grown high-quality single crystals of the colossal-magnetoresistance (CMR) material La0.7Ca0.3MnO3 by using the laser heated pedestal growth (LHPG) method. Samples were grown as fibers of different diameters, and with lengths of the order of centimeters. Their composition and structure were verified through X-ray diffraction, scanning electron microcopy with EDX (Energy Dispersive X-ray Analysis) and by Rietveld analysis. The quality of the crystalline fibers was confirmed by Laue and EBSD (Electron Backscatter Diffraction) patterns. Rocking curves performed along the fiber axis revealed a half-height width of 0.073 degrees. The CMR behavior was confirmed by electrical resistivity and magnetization measurements as a function of temperature.Comment: 11 pages (including 3 figures); to appear in Appl. Phys. Let

Adubação nitrogenada e densidade de plantas com hibridos de milho em sistema plantio direto nas regiões sudoeste piauiense e sul maranhense.

Conduziu-se este trabalho com o objetivo de estudar o comportamento produtivo de híbridos de milho em relação à dose de nitrogênio e à densidade de plantas no sistema plantio direto em solos das regiões sudoeste piauiense e sul maranhense.bitstream/item/38330/1/CT197.pd

Estudo das alterações imunofenotípicas de populações linfocitárias em doentes com artrite reumatóide

A Artrite Reumatóide (AR) é uma doença auto-imune que devido às suas características tornam por si só os indivíduos afectados susceptíveis a infecções; imunocomprometimento que por vezes ainda é agravado por terapêuticas imunomodulatórias usadas para o seu tratamento. Este estudo tem como objectivo analisar, as populações/sub-populações de linfócitos conjuntamente com a análise das imunoglobulinas G e M, apresentando como factores discriminatórios, a idade, o sexo e a presença de terapêutica imunomodulatória, nos doentes com AR. Os resultados sugerem uma depleção significativa dos linfócitos B e um aumento dos T, os quais dão indícios para um aumento da susceptibilidade a infecções.Rheumatoid arthritis (RA) is an autoimmune disease that due to their characteristics make itself affected individuals susceptible to infections, immunosuppression which sometimes is still aggravated by immunomodulatory therapies used to treat it. This study has as objective analyze the populations/sub-populations of lymphocytes together with the analysis of immunoglobulins G and M, presenting as discriminatory factors age, sex and the presence of immunomodulatory therapy in patients with RA. The results suggest a significant depletion of B cells and an increase in T, which give clues to an increased susceptibility to infections

Noninvasive anatomical and functional assessment of coronary artery disease.

INTRODUCTION AND OBJECTIVE: In suspected coronary artery disease (CAD), invasive coronary angiography (ICA) is traditionally the diagnostic tool of choice. However, patients often have no significant disease. Moreover, assessment of fractional flow reserve (FFR) has been shown to have prognostic implications. Recently, coronary computed tomography angiography (CTA) and cardiac magnetic resonance (CMR) myocardial perfusion imaging (CMR-Perf) have gained increasing attention through their accurate anatomical and functional assessment, respectively. We studied the added value of integrating these tests (CT+CMRint) in the diagnosis of CAD, with FFR as the reference standard. METHODS: We included 101 patients consecutively referred for outpatient assessment of CAD who underwent CTA and CMR-Perf prior to ICA with FFR assessment. Lesions were considered positive by CT+CMRint only if positive in the two tests alone. The mean follow-up was 2.9±0.6 years. RESULTS: All patients completed the study protocol without adverse effects. Forty-four patients had CAD by FFR. CTA had excellent sensitivity and negative predictive value (100%) but, as expected, its specificity and positive predictive value were lower (61% and 67%, respectively). Diagnostic accuracy by FFR was 78% for CTA, 88% for CMR-Perf and 92% for CT+CMRint. Regarding diagnostic accuracy, CT+CMRint showed statistically significant superiority (AUC=0.917, 95% CI 0.845-0.963) compared with CTA (AUC=0.807, 95% CI 0.716-0.879, p=0.0057) or CMR-Perf (AUC=0.882, 95% CI 0.802-0.938, p=0.0398) alone. Regarding prediction of revascularization, the integrated protocol maintained its superior performance. CONCLUSIONS: CT+CMRint showed superior diagnostic accuracy and could thus lead to a considerable reduction in invasive procedures for CAD diagnosis, with less risk and greater patient comfort

Graphene oxide and a GO/ZnO nanocomposite as catalysts for epoxy ring-opening of epoxidized soybean fatty acids methyl esters

In this work, the grapheme oxide (GO) and GO/ZnO nanocomposite were successfully obtained from the oxidation of graphite and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). In the GO/ZnO nanocomposite, the GO sheets were coated with aggregated ZnO nanoneedles with ca. 20 nm of diameter. The obtained materials were used as heterogeneous catalysts for acetylation of Soybean Fatty Acids Methyl Esters (FAME), promoting the epoxy ring-opening using acetic anhydride. The epoxy ring was almost completely opened in the presence of GO or GO/ZnO nanocomposites, with conversion rates up to 99% and selectivity of ca. 90%, and partially opened using only ZnO. The GO/Zn and GO catalysts were reused three times with conversion rates of ca. 85 and 74%, respectively