EU3+-O2- associates luminescence in Ba2SiO4

Results on the luminescence properties of Eu3+ in Ba2SiO4 sites and the presence of Eu3+-O2- associates are reported. The Ba2SiO4:Eu3+ emission spectra showed two groups of transitions that might be assigned to the D-5(0) --> F-7(0) one. In each group at least two lines were observed. This is possibly related to the different emission centers, attributed to Eu3+ occupying the Ba2+ sites, and to Eu3+-O2- associates in interstices. Excitation spectra presented two CT bands at 270 and 340 nm related to each emission center.

Europium(III) Concentration Effect on the Spectroscopic and Photoluminescent Properties of BaMoO4:Eu

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Film based on Y2O3: Eu3+ (5 mol% of Eu3+) for flat panel display

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

The Role of the Eu3+ Concentration on the SrMoO4:Eu Phosphor Properties: Synthesis, Characterization and Photophysical Studies

SrMoO4 doped with rare earth are still scarce nowadays and have attracted great attention due to their applications as scintillating materials in electro-optical like solid-state lasers and optical fibers, for instance. In this work Sr1-xEuxMoO4 powders, where x = 0.01; 0.03 and 0.05, were synthesized by Complex Polymerization (CP) Method. The structural and optical properties of the SrMoO4:Eu3+ were analyzed by powder X-ray diffraction patterns, Fourier Transform Infra-Red (FTIR), Raman Spectroscopy, and through Photoluminescent Measurements (PL). Only a crystalline scheelite-type phase was obtained when the powders were heat-treated at 800 A degrees C for 2 h, 2 theta = 27.8A degrees (100% peak). The excitation spectra of the SrMoO4:Eu3+ (lambda(Em.) = 614 nm) presented the characteristic band of the Eu3 + 5L6 transition at 394 nm and a broad band at around 288 nm ascribed to the charge-transfer from the O (2p) state to the Mo (4d) one in the SrMoO4 matrix. The emission spectra of the SrMoO4:Eu3+ powders (lambda(Exc.) = 394 and 288 nm) show the group of sharp emission bands among 523-554 nm and 578-699 nm, assigned to the D-5(1)-> F-7(0,1and 2) and D-5(0)-> F-7(0,1,2,3 and 4), respectively. The band related to the D-5(0)-> F-7(0) transition indicates the presence of Eu3+ site without inversion center. This hypothesis is strengthened by the fact that the band referent to the D-5(0)-> F-7(2) transition is the most intense in the emission spectra.

Fatores perinatais associados a rec��m-nascidos de termo com pH<7,1 na art��ria umbilical e ��ndice de Apgar <7,0 no 5�� minuto

OBJETIVO: Avaliar os fatores perinatais associados a rec��m-nascidos de termo com pH<7,1 na art��ria umbilical e ��ndice de Apgar no 5�� min<7,0. M��TODOS: Estudo retrospectivo com delineamento caso-controle, realizado ap��s revis��o dos prontu��rios de todos os nascimentos ocorridos entre setembro/1998 e mar��o/2008, no Hospital Geral de Caxias do Sul. Foi considerado fator de inclus��o os rec��m-nascidos de termo que apresentaram ��ndice de Apgar no 5�� min <7,0 e pH de art��ria umbilical <7,1. Na an��lise univariada foi utilizado o teste t de Student e Mann-Whitney para as vari��veis cont��nuas, o teste do c�� para as vari��veis dicot��micas e estimativa de risco pelo odds ratio (OR). Foi utilizado um valor de p<0,05 como estatisticamente significativo. RESULTADOS: De um total de 15.495 nascimentos consecutivos observaram-se 25 neonatos (0,16%) de termo com pH<7,1 na art��ria umbilical e ��ndice de Apgar no 5�� min <7,0. Apresentaram associa����o significativa com o evento acid��tico a apresenta����o p��lvica (OR=12,9; p<0,005), parto ces��reo (OR=3,5; p<0,01) e cardiotocografia intraparto alterada (OR=7,8; p<0,02). Dentre as caracter��sticas fetais, associaram-se o d��ficit de base (-15,0 versus -4,5; p<0,0001), necessidade de interna����o em unidade de terapia intensiva neonatal (OR=79,7; p<0,0001) e necessidade de reanima����o (OR=12,2; p<0,0001). CONCLUS��O: Baixo ��ndice de Apgar no 5�� min de vida associado a pH<7,1 na art��ria umbilical pode predizer desfechos neonatais desfavor��veis.

Estudo de reatividade e resolu����o enantiom��rica do (+-)-10-exo-hidr��xipentaciclo[6.2.1.1 3,6.0 2,7. 0 5.9] dodecan-4-ona

Neste trabalho, realizou-se a s��ntese do ceto-��lcool pentacicl��co (��)-5, assim como o estudo de reatividade do grupo carbonila do mesmo frente a rea����es de oxima����o e redu����o. Realizou-se tamb��m a resolu����o enantiom��rica do composto (��)-5 atrav��s de rea����o de transesterifica����o com acetato de vinila catalisada pela lipase da Candida rugosa. Altos excessos enantiom��ricos foram obtidos (>95%, RMN) tanto para o ��lcool (+)-5 quanto para o ��ster formado (-)-8. Sugere-se a exist��ncia de uma interconvers��o enantiom��rica no composto (+)-5, devido a observa����o de mistura rac��mica, quando o mesmo foi analisado por cromatografia gasosa em coluna quiral. Um mecanismo para tal interconvers��o, o qual envolve um rearranjo intramolecular, �� proposto.

In vivo biochemical 7.0 Tesla magnetic resonance: preliminary results of dGEMRIC, zonal T2, and T2* mapping of articular cartilage

INTRODUCTION: Ultra-high-field whole-body systems (7.0 T) have a high potential for future human in vivo magnetic resonance imaging (MRI). In musculoskeletal MRI, biochemical imaging of articular cartilage may benefit, in particular. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and T2 mapping have shown potential at 3.0 T. Although dGEMRIC, allows the determination of the glycosaminoglycan content of articular cartilage, T2 mapping is a promising tool for the evaluation of water and collagen content. In addition, the evaluation of zonal variation, based on tissue anisotropy, provides an indicator of the nature of cartilage ie, hyaline or hyaline-like articular cartilage.Thus, the aim of our study was to show the feasibility of in vivo dGEMRIC, and T2 and T2* relaxation measurements, at 7.0 T MRI; and to evaluate the potential of T2 and T2* measurements in an initial patient study after matrix-associated autologous chondrocyte transplantation (MACT) in the knee. MATERIALS AND METHODS: MRI was performed on a whole-body 7.0 T MR scanner using a dedicated circular polarization knee coil. The protocol consisted of an inversion recovery sequence for dGEMRIC, a multiecho spin-echo sequence for standard T2 mapping, a gradient-echo sequence for T2* mapping and a morphologic PD SPACE sequence. Twelve healthy volunteers (mean age, 26.7 +/- 3.4 years) and 4 patients (mean age, 38.0 +/- 14.0 years) were enrolled 29.5 +/- 15.1 months after MACT. For dGEMRIC, 5 healthy volunteers (mean age, 32.4 +/- 11.2 years) were included. T1 maps were calculated using a nonlinear, 2-parameter, least squares fit analysis. Using a region-of-interest analysis, mean cartilage relaxation rate was determined as T1 (0) for precontrast measurements and T1 (Gd) for postcontrast gadopentate dimeglumine [Gd-DTPA(2-)] measurements. T2 and T2* maps were obtained using a pixelwise, monoexponential, non-negative least squares fit analysis; region-of-interest analysis was carried out for deep and superficial cartilage aspects. Statistical evaluation was performed by analyses of variance. RESULTS: Mean T1 (dGEMRIC) values for healthy volunteers showed slightly different results for femoral [T1 (0): 1259 +/- 277 ms; T1 (Gd): 683 +/- 141 ms] compared with tibial cartilage [T1 (0): 1093 +/- 281 ms; T1 (Gd): 769 +/- 150 ms]. Global mean T2 relaxation for healthy volunteers showed comparable results for femoral (T2: 56.3 +/- 15.2 ms; T2*: 19.7 +/- 6.4 ms) and patellar (T2: 54.6 +/- 13.0 ms; T2*: 19.6 +/- 5.2 ms) cartilage, but lower values for tibial cartilage (T2: 43.6 +/- 8.5 ms; T2*: 16.6 +/- 5.6 ms). All healthy cartilage sites showed a significant increase from deep to superficial cartilage (P < 0.001). Within healthy cartilage sites in MACT patients, adequate values could be found for T2 (56.6 +/- 13.2 ms) and T2* (18.6 +/- 5.3 ms), which also showed a significant stratification. Within cartilage repair tissue, global mean values showed no difference, with 55.9 +/- 4.9 ms for T2 and 16.2 +/- 6.3 ms for T2*. However, zonal assessment showed only a slight and not significant increase from deep to superficial cartilage (T2: P = 0.174; T2*: P = 0.150). CONCLUSION: In vivo T1 dGEMRIC assessment in healthy cartilage, and T2 and T2* mapping in healthy and reparative articular cartilage, seems to be possible at 7.0 T MRI. For T2 and T2*, zonal variation of articular cartilage could also be evaluated at 7.0 T. This zonal assessment of deep and superficial cartilage aspects shows promising results for the differentiation of healthy and affected articular cartilage. In future studies, optimized protocol selection, and sophisticated coil technology, together with increased signal at ultra-high-field MRI, may lead to advanced biochemical cartilage imaging.

Nessy 7.0: entorno de inyecci��n de fallos para Artix-7

El hardware reconfigurable es una tecnolog��a emergente en aplicaciones espaciales.Debido a las caracter��sticas de este hardware, pues su configuraci��n l��gica queda almacenada en memoria RAM est��tica, es susceptible de diversos errores que pueden ocurrir con mayor frecuencia cuando es expuesta a entornos de mayor radiaci��n, como en misiones de exploraci��n espacial. Entre estos se encuentran los llamados SEU o Single Event Upset, y suelen ser generados por part��culas c��smicas, pues pueden tener la capacidad de descargar un transistor y de este modo alterar un valor l��gico en memoria, y por tanto la configuraci��n l��gica del circuito. Por ello que surge la necesidad de desarrollar t��cnicas que permitan estudiar las vulnerabilidades de diversos circuitos, de forma econ��mica y r��pida, adem��s de t��cnicas de protecci��n de los mismos. En este proyecto nos centraremos en desarrollar una herramienta con este prop��sito, Nessy 7.0. La plataforma nos permitir�� emular, detectar y analizar posibles errores causados por la radiaci��n en los sistemas digitales. Para ello utilizaremos como dispositivo controlador, una Raspberry Pi 3, que contendr�� la herramienta principal, y controlar�� y se comunicar�� con la FPGA que implementar�� el dise��o a testear, en este caso una placa Nexys 4 DDR con una FPGA Artix-7. Finalmente evaluaremos un par de circuitos con la plataforma.

Peptide binding to HLA-DP proteins at pH 5.0 and pH 7.0:a quantitative molecular docking study

Background: HLA-DPs are class II MHC proteins mediating immune responses to many diseases. Peptides bind MHC class II proteins in the acidic environment within endosomes. Acidic pH markedly elevates association rate constants but dissociation rates are almost unchanged in the pH range 5.0 - 7.0. This pH-driven effect can be explained by the protonation/deprotonation states of Histidine, whose imidazole has a pKa of 6.0. At pH 5.0, imidazole ring is protonated, making Histidine positively charged and very hydrophilic, while at pH 7.0 imidazole is unprotonated, making Histidine less hydrophilic. We develop here a method to predict peptide binding to the four most frequent HLA-DP proteins: DP1, DP41, DP42 and DP5, using a molecular docking protocol. Dockings to virtual combinatorial peptide libraries were performed at pH 5.0 and pH 7.0. Results: The X-ray structure of the peptide - HLA-DP2 protein complex was used as a starting template to model by homology the structure of the four DP proteins. The resulting models were used to produce virtual combinatorial peptide libraries constructed using the single amino acid substitution (SAAS) principle. Peptides were docked into the DP binding site using AutoDock at pH 5.0 and pH 7.0. The resulting scores were normalized and used to generate Docking Score-based Quantitative Matrices (DS-QMs). The predictive ability of these QMs was tested using an external test set of 484 known DP binders. They were also compared to existing servers for DP binding prediction. The models derived at pH 5.0 predict better than those derived at pH 7.0 and showed significantly improved predictions for three of the four DP proteins, when compared to the existing servers. They are able to recognize 50% of the known binders in the top 5% of predicted peptides. Conclusions: The higher predictive ability of DS-QMs derived at pH 5.0 may be rationalised by the additional hydrogen bond formed between the backbone carbonyl oxygen belonging to the peptide position before p1 (p-1) and the protonated ��-nitrogen of His 79��. Additionally, protonated His residues are well accepted at most of the peptide binding core positions which is in a good agreement with the overall negatively charged peptide binding site of most MHC proteins. �� 2012 Patronov et al.; licensee BioMed Central Ltd.

An X-ray study of the SNR G344.7-0.1 and the central object CXOU J170357.8-414302

Aims. We report results of an X-ray study of the supernova remnant (SNR) G344.7-0.1 and the point-like X-ray source located at the geometrical center of the SNR radio structure. Methods. The morphology and spectral properties of the remnant and the central X-ray point-like source were studied using data from the XMM-Newton and Chandra satellites. Archival radio data and infrared Spitzer observations at 8 and 24 mu m were used to compare and study its multi-band properties at different wavelengths. Results. The XMM-Newton and Chandra observations reveal that the overall X-ray emission of G344.7-0.1 is extended and correlates very well with regions of bright radio and infrared emission. The X-ray spectrum is dominated by prominent atomic emission lines. These characteristics suggest that the X-ray emission originated in a thin thermal plasma, whose radiation is represented well by a plane-parallel shock plasma model (PSHOCK). Our study favors the scenario in which G344.7-0.1 is a 6 x 10^3 year old SNR expanding in a medium with a high density gradient and is most likely encountering a molecular cloud on the western side. In addition, we report the discovery of a soft point-like X-ray source located at the geometrical center of the radio SNR structure. The object presents some characteristics of the so-called compact central objects (CCO). However, its neutral hydrogen absorption column (N_H) is inconsistent with that of the SNR. Coincident with the position of the source, we found infrared and optical objects with typical early-K star characteristics. The X-ray source may be a foreground star or the CCO associated with the SNR. If this latter possibility were confirmed, the point-like source would be the farthest CCO detected so far and the eighth member of the new population of isolated and weakly magnetized neutron stars.

Anomalous resistivity at the structural phase transition of polycrystalline SnTe

An excess resistivity has been observed in thin film polycrystalline samples of SnTe with low carrier concentration and is attributed to the additional scattering due to the phonon softening associated with the structural phase transition.

Luminesc��ncia em sistemas coloidais polifosfato-polioxometalatos

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Film based on Y2O3: Eu3+ (5 mol% of Eu3+) for flat panel display

This paper reports on Y2O3:Eu3+ containing 1 mol% of Ag-0 nanoparticle films recovered with a SiO2 layer by using glass foil as a substrate for a possible optical display device application. The obtained film showed an intense emission at 612 nm due to the Eu3+ 5D0 -&gt; F-7(2) hypersensitive transition, a high transmittance in that emission range, an excellent optical quality, and a high absorption only below 300 nm. Moreover, despite the presence of the SiO2 layer used to improve the phosphor adhesion on Corning (R) foil substrates, the intensity ratios between the emissions assigned to Eu3+ D-5(0) -&gt; F-7(2) (dipole electric transition) and D-5(0) -&gt; F-7(1) (dipole magnetic transition) were not affected by it. The x and y coordinate values found in the 1931 Commission Internationale de l'Eclairage Chromaticity Diagram for this film reveal that it has a suitable pure red color emission for optical displays devices. (C) 2012 Elsevier B. V. All rights reserved.

The effect of Eu3+ concentration on the Y2O3 host lattice obtained from citrate precursors

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)