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Para investigar o impacto em resultados pós-natais do uso de ciclo único de betametasona para maturação pulmonar em gestações (únicas, sem malformações fetais ou neonatais) com diástole zero ou diástole reversa à dopplervelocimetria das artérias umbilicais, foi conduzido estudo de coorte histórico com 62 recém-nascidos entre 26 e 34 semanas. Desses, 31 tinham uso antenatal do corticóide (nascidos entre maio de 2004 e julho de 2006) e 31 controles sem o uso da droga (nascidos entre janeiro de 2000 a março de 2004), pareados individualmente segundo índice de pulsatilidade para veias do ducto venoso (até 1,0 ou entre 1,01 e 1,50), idade gestacional ao nascimento (variação máxima de seis dias) e peso ao nascimento (variação máxima de 10%). Avaliaram-se: índice de Apgar de primeiro e quinto minutos, internação em unidade de terapia intensiv...
Strontium titanate (SrTiO 3 ) thin films were prepared by dip-coating Si(111) single-crystal substrates in citrate solutions of ethylene glycol, considering several citric acid/ethylene glycol (CA/EG) ratios. Measurements of intrinsic viscosity indicate that increasing the amount of EG increases the precursors' polymeric chains and increases the weight loss. After deposition the substrates were dried on a hotplate (≈150 °C); this was followed by heat treatment at temperatures ranging from 500 to 700 °C using heating and cooling rates of 1 °C min −1 . SEM and optical microscopy investigations of the sintered films obtained from different CA/EG ratios indicate that there is a critical thickness above which the films present cracks. This critical thickness for SrTiO 3 films deposited on the Si(111) substrate is about 150 nm. Measurements...
Samarium doped barium zirconate titanate ceramics with general formula Ba1-x Sm-2x/3](Zr0.05Ti0.95)O-3 x = 0, 0.01, 0.02, and 0.03] were prepared by high energy ball milling method. X-ray diffraction patterns and micro-Raman spectroscopy confirmed that these ceramics have a single phase with a tetragonal structure. Rietveld refinement data were employed to model BaO12], SmO12], ZrO6], and TiO6] clusters in the lattice. Scanning electron microscopy shows a reduction in average grain size with the increase of Sm3+ ions into lattice. Temperature-dependent dielectric studies indicate a ferroelectric phase transition and the transition temperature decreases with an increase in Sm3+ ion content. The nature of the transition was investigated by the Curie-Weiss law and it is observed that the diffusivity increases with Sm3+ ion content. The fe...
The self-assembly of the alanine-rich amphiphilic peptides Lys(Ala)6Lys (KA6K) and Lys(Ala)6Glu (KA6E)with homotelechelic or heterotelechelic charged termini respectively has been investigated in aqueous solution. These peptides contain hexa-alanine sequences designed to serve as substrates for the enzyme elastase. Electrostatic repulsion of the lysine termini in KA6K prevents self-assembly, whereas in contrast KA6E is observed, through electron microscopy, to form tape-like fibrils, which based on X-ray scattering contain layers of thickness equal to the molecular length. The alanine residues enable efficient packing of the side-chains in a beta-sheet structure, as revealed by circular dichroism, FTIR and X-ray diffraction experiments. In buffer, KA6E is able to form hydrogels at sufficiently high concentration. These were used as su...
A lead-scintillating fiber calorimeter has been built to fill the gap between endcap and barrel of the L3 BGO electromagnetic calorimeter. We report details of the construction, as well as results from test-beam and simulation.
The barrel part of the CMS electromagnetic calorimeter consists of about 60000 PWO crystals and will be assembled in two Regional Centers, nearby Rome and at CERN. Two automatic machines have been designed to check the crystal quality before assembly. The main crystal characteristics are compared to a set of specifications included in the contract with the crystal producers. The stability and intercalibration between the two is a fundamental issue, which has to be controlled during the whole construction phase. This paper describes the checks that were made in order to cross calibrate the measurements and to guarantee a proper selection of crystals for the detector.
The CMS electromagnetic calorimeter (ECAL) comprises 75848 scintillating lead tungstate crystals. 61200 crystals are contained in the ECAL Barrel section and are read out by avalanche photodiode (APD) with internal gain of about 50. This gain is achieved with a high voltage (HV) of about 400 Volts. The gain stability requirement implies a supply voltage stable to within 0.01%. We describe our experience with the installed Barrel HV power supply system, which has been used for data taking since 2008.
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