NIR luminescent Er3+/Yb3+ co-doped SiO2-ZrO2 nanostructured planar and channel waveguides: Optical and structural properties

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

Effect of high and low molecular weight glutenin subunits, and subunits of gliadin on physicochemical parameters of different wheat genotypes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Experimental visceral leishmaniasis in high and low antibody - producer mice (selection IV-A)

A leishmaniose é uma infecção parasitária cuja imunidade protetora envolve a ativação de macrófagos. Neste trabalho avaliamos a susceptibilidade de camundongos H e L (bons e maus produtores de anticorpos, respectivamente) da seleção IV-A, à infecção com o protozoário L. donovani. Camundongos H infectados com 10(7) amastigotas por via intravenosa foram mais suscetíveis, apresentando maior carga parasitária tanto no fígado quanto no baço. Após 60 dias de infecção ambas as linhagens apresentaram um aumento no índice esplênico. Esta esplenomegalia foi conseqüência, pelo menos parcialmente, de um aumento no número de células esplênicas. Os resultados indicam que a seleção IV-A é susceptível à infecção com L. donovani e que dentro desta seleção a linhagem H apresenta maior suscetibilidade do que a linhagem L.

Low optical loss planar waveguides prepared in an organic-inorganic hybrid system

HfO2-(3-glycidoxipropil)trimethoxisilane (GPTS) planar waveguides were prepared by a sol-gel route. A stable sol of Hafnia nanocrystals was prepared and characterized by photon correlation spectroscopy and high resolution transmission electron microscopy. The suspension was incorporated in GPTS host and the resulting sol was deposited on borosilicate substrates by the spin coating technique. Optical properties such as refractive index, thickness, number of propagating modes, and attenuation coefficient were measured at 632.8, 543.5, and 1550 nm by the prism coupling technique as a function of the HfO2 content. (C) 2000 American Institute of Physics. [S0003-6951(00)03348-9].

High Verdet constant Ga : S : La : O chalcogenide glasses for magneto-optical devices

The magneto-optical rotation at room temperature was measured for three Ga:S:La:O chalcogenide glasses at several laser lines in the visible. The first sample was a binary system constituted by 70 mol % Ga2S3 and 30 mol % La2O3, whereas in the second and third ones the lanthanum oxide was partially substituted by lanthanum sulfide, keeping the amount of gallium sulfide fixed. A pulsed magnetic field between 50 and 80 kG was used for the Faraday rotation measurements. The Verdet constant for one of the ternary samples was found to be as high as 0.205 min G(-1) cm(-1) at 543 nm, indicating that these chalcogenide glasses are very promising for magneto-optical applications. The data for each sample were fitted using the expected analytical expression for the magneto-optical dispersion. Measurements of the refractive index of the glasses at 632.8 nm are also reported. Data on the magneto-optical properties of two high Verdet constant, heavy-metal oxide diamagnetic glasses are also included for comparison. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)00102-6].

High volume peritoneal dialysis for acute renal failure

Background. Peritoneal dialysis (PD) is still widely used for acute renal failure (ARF) in developing countries despite concerns about its inadequacy. Continuous PD has been evaluated in ARF by analyzing the resolution of metabolic abnormality and normalization of plasma pH, bicarbonate, and potassium.Methodology: A prospective study was performed on 30 ARF patients who were assigned to high-dose continuous PD (Kt/V = 0.65 per session) via a flexible catheter (Tenckhoff) and automated PD with a cycler. Fluid removal, pH and metabolic control, protein Loss, and patient outcome were evaluated.Results: Patients received 236 continuous PD sessions; 76% were admitted to ICUs. APACHE II score was 32.2 +/- 8.65. BUN concentrations stabilized after 3 sessions, creatinine after 4, and bicarbonate and pH after 2. Fluid removal was 2.1 +/- 0.62 L/day. Creatinine and urea clearances were 15.8 +/- 4.16 and 17.3 +/- 5.01 mL/minute respectively. Normalized creatinine clearance and urea Kt/V values were 110.6 +/- 22.5 L/week/1.73 m(2) body surface area and 3.8 +/- 0.6 respectively. Solute reduction index was 41% +/- 6.5% per session. Serum albumin values remained stable in spite of considerable protein tosses (median 21.7 g/day, interquartile range 9.1 - 29.8 g/day). Regarding ARF outcome, 23% of patients presented renal function recovery, 13% remained on dialysis after 30 days of follow-up, and 57% died.Conclusion: High-dose continuous PD by flexible catheter and cycler was an effective treatment for ARF. It provided high solute removal, allowing appropriate metabolic and pH control, and adequate dialysis dose and fluid removal. Continuous PD can therefore be considered an alternative to other forms of renal replacement therapy in ARF.

Planar waveguides based on nanocrystalline and Er3+ doped SnO2

Luminescent SnO2: x%mol Er3+ (x=0.1-2.0) thin films have been spin coated on borosilicate and silica substrates from water colloidal suspensions that could be prepared containing up to 40% in weight SnO2 nanocrystalline powders. High Resolution Transmission Electron Microscopy results show the well known SnO2 cassiterite structure and nanocrystallites around 10 nm in diameter, corroborating results from X-ray diffraction. Mono and multi layers have been prepared from the stable colloidal suspensions and films thickness was observed to increase linearly, up to 200 nm, with the colloidal suspensions nanoparticles amount. Excitation and emission spectra have been measured and Er3+ ions were found to be essentially incorporated into the cassiterite structure, substituting for Sn4+, for doping concentration lower than 0.05 mol%. Er3+ ions also appear segregated at the grains surface for higher doping concentration. The optical parameters (refractive index, thickness and propagating modes) of a waveguide sample were measured at 632.8 and 543.4 nm by the prism coupling technique. A monomodal waveguide was obtained with attenuation loss of 3.5 dB/cm along a 2.5 cm optical path.

High dielectric constant of SrTiO3 thin films prepared by chemical process

SrTiO3 thin films were prepared by the polymeric precursor method and deposited by spin-coating onto Pt/Ti/SiO2/Si(100) substrates. The spin-coated films heat treated at 700 degrees C were crack-free, dense, and homogeneous. Microstructural and morphological evaluations were followed by grazing incident X-ray, scanning electron microscopy and atomic force microscopy. Dielectric studies indicated a dielectric constant of about 475, which is higher than that of ceramic SrTiO3, and a factor dissipation of about 0.050 at 100 kHz. SrTiO3 thin films were found to have paraelectric properties with C-V characteristics. (C) 2000 Kluwer Academic Publishers.

Underlying dynamics of typical fluctuations of an emerging market price index: the Heston model from minutes to months

We investigate the Heston model with stochastic volatility and exponential tails as a model for the typical price fluctuations of the Brazilian São Paulo Stock Exchange Index (IBOVESPA). Raw prices are first corrected for inflation and a period spanning 15 years characterized by memoryless returns is chosen for the analysis. Model parameters are estimated by observing volatility scaling and correlation properties. We show that the Heston model with at least two time scales for the volatility mean reverting dynamics satisfactorily describes price fluctuations ranging from time scales larger than 20min to 160 days. At time scales shorter than 20 min we observe autocorrelated returns and power law tails incompatible with the Heston model. Despite major regulatory changes, hyperinflation and currency crises experienced by the Brazilian market in the period studied, the general success of the description provided may be regarded as an evidence for a general underlying dynamics of price fluctuations at intermediate mesoeconomic time scales well approximated by the Heston model. We also notice that the connection between the Heston model and Ehrenfest urn models could be exploited for bringing new insights into the microeconomic market mechanics. (c) 2005 Elsevier B.V. All rights reserved.

Erbium-activated HfO2-based waveguides for photonics

Silica-based sol-gel waveguides activated by Er3+ ions are attractive materials for integrated optic devices. 70SiO(2)-30HfO(2) planar waveguides, doped with Er3+ concentrations ranging from 0.01 to 4 mol%, were prepared by sol-get route. The films were deposited on v-SiO2 and silica-on-silicon substrates, using dip-coating technique. The waveguides show a homogeneous surface morphology, high densification degree and uniform refractive index across the thickness. Emission in the C-telecommunication band was observed at room temperature for ill the samples upon excitation at 980 nm. The shape is found to be almost independent on erbium content, with a FWHM between 44 and 48 nm. The I-4(13/2) level decay curves presented a single-exponential profile, with a lifetime ranging between 1.1 and 6.7 ms, depending on the erbium concentration. The waveguide deposited on silica-on-silicon substrate supports one single propagation mode at 1.5 mum with a confinement coefficient of 0.85, and a losses of about 0.8 dB/cm at 632.8 nm. (C) 2003 Elsevier B.V. All rights reserved.

Holographic recording in [Sb(Po-3)(3)](n)-Sb2O3 glassy films by photoinduced volume and refraction index changes

Glassy films of 0.2[Sb(PO3)(3)]-0,8Sb(2)O(3) with 0.8 mum-thickness were deposited on quartz substrates by electron beam evaporation. A contraction in the film thickness (photoinduced decrease in volume) and photobleaching effect associated with a decrease of up to 25% in the index of refraction has been observed in the films after irradiation near the bandgap (3.89 eV), using the 350.7 nm (3.54 eV) Kr+ ion laser line with 2.5 W/cm(2) for 30 min. A loss of 30% in the phosphorus concentration was measured by wavelength dispersive X-ray microanalysis in the film after laser irradiation with 5.0 W/cm(2) for 1.0 h. These photoinduced changes in the samples are dependent on the power density and intensity profile of the laser beam. Using a Lloyd's mirror setup for continuous wave holography it was possible to record holographic gratings with period from 500 nm up to 20 mum and depth profile of similar to50 nm in the films after laser irradiation with 5.0 W/cm(2) for 1 h. Real-time diffraction efficiency measurements have shown that ultraviolet irradiation induces first a refractive index grating formation, and after this, the photocon traction effect takes place generating an irreversible relief grating. Diffraction efficiency up to 10% was achieved for the recorded gratings. 3D-refraction index measurements and atomic force microscopy images are presented. (C) 2004 Elsevier B.V. All rights reserved.

High Curie point CaBi2Nb2O9 thin films: A potential candidate for lead-free thin-film piezoelectrics

CaBi2Nb2O9 (CBNO) thin films deposited on platinum coated silicon substrates by the polymeric precursor method exhibited good structural, dielectric, and piezoelectric characteristics. Capacitance-voltage measurements indicated good ferroelectric polarization switching characteristics. Remanent polarization and drive voltage values were 4.2 mu C/cm(2) and 1.7 V for a maximum applied voltage of 10 V. The film has a piezoelectric coefficient d(33) equal to 60 pm/V, current density of 0.7 mu A/cm(2), and Curie temperature of 940 degrees C. The polar-axis-oriented CBNO is a promising candidate for use in lead-free high Curie point in ferroelectric and piezoelectric devices. (c) 2006 American Institute of Physics.

Kinetic characterization of hypophosphatasia mutations with physiological substrates

We have analyzed 16 missense mutations of the tissue-nonspecific AP (TNAP) gene found in patients with hypophosphatasia. These mutations span the phenotypic spectrum of the disease, from the lethal perinatal/infantile forms to the less severe adult and odontohypophosphatasia. Site-directed mutagenesis was used to introduce a sequence tag into the TNAP cDNA and eliminate the glycosylphosphatidylinositol (GPI)-anchor recognition sequence to produce a secreted epitope-tagged TNAP (setTNAP). The properties of GPI-anchored TNAP (gpiTNAP) and setTNAP were found comparable. After introducing each single hypophosphatasia mutation, the setTNAP and mutant TNAP cDNAs were expressed in COS-1 cells and the recombinant flagged enzymes were affinity purified. We characterized the kinetic behavior, inhibition, and heat stability properties of each mutant using the artificial substrate p-nitrophenylphosphate (pNPP) at pH 9.8. We also determined the ability of the mutants to metabolize two natural substrates of TNAP, that is, pyridoxal-5'-phosphate (PLP) and inorganic pyrophosphate (PPi), at physiological pH. Six of the mutant enzymes were completely devoid of catalytic activity (R54C, R54P, A94T, R206W, G317D, and V365I), and 10 others (A16V, A115V, A160T, A162T, E174K, E174G, D277A, E281K, D361V, and G439R) showed various levels of residual activity. The A160T substitution was found to decrease the catalytic efficiency of the mutant enzyme toward pNPP to retain normal activity toward PPi and to display increased activity toward PLP. The A162T substitution caused a considerable reduction in the pNPPase, PPiase, and PLPase activities of the mutant enzyme. The D277A mutant was found to maintain high catalytic efficiency toward pNPP as substrate but not against PLP or PPi. Three mutations ( E174G, E174K, and E281K) were found to retain normal or slightly subnormal catalytic efficiency toward pNPP and PPi but not against PLP. Because abnormalities in PLP metabolism have been shown to cause epileptic seizures in mice null for the TNAP gene, these kinetic data help explain the variable expressivity of epileptic seizures in hypophosphatasia patients.

Effect of high hydrostatic pressure processing on rheological and textural properties of probiotic low-fat yogurt fermented by different starter cultures

The effect of milk processing on rheological and textural properties of probiotic low-fat yogurt (fermented by two different starter cultures) was studied. Skim milk fortified with skim milk powder was subjected to three treatments: (1) thermal treatment at 85C for 30 min; (2) high hydrostatic pressure (HHP) at 676 MPa for 5 min; and (3) combined treatments of HHP (676 MPa for 5 min) and heat (85C for 30 min). The processed milk was fermented using two different starter cultures containing Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus and Bifidobacterium longum at inoculation rates of 0.1 and 0.2%. Rheological parameters were determined and a texture profile analysis was carried out. Yogurts presented different rheological behaviors according to the treatment used, which could be attributed to structural phenomena. The combined HHP and heat treatment of milks resulted in yogurt gels with higher consistency index values than gels obtained from thermally treated milk. The type of starter culture and inoculation rate, providing different fermentation pathways, also affected the consistency index and textural properties significantly. The combined HHP and heat treatment of milks before fermentation, and an inoculation rate of 0.1% (for both cultures), led to desirable rheological and textural properties in yogurt, which presented a creamy and thick consistency that does not require the addition of stabilizers.

Thin films prepared from tungstate glass matrix

Vitreous samples containing high concentrations of WO3 (above 40% M) have been used as a target to prepare thin films. Such films were deposited using the electron beam evaporation method onto soda-lime glass substrates. These films were characterized by X-ray diffraction (XRD), perfilometry, X-ray energy dispersion spectroscopy (EDS), M-Lines and UV-vis absorption spectroscopy. In this work, experimental parameters were established to obtain stable thin films showing a chemical composition close to the glass precursor composition and with a high concentration of WO3. These amorphous thin films of about 4 mu m in thickness exhibit a deep blue coloration but they can be bleached by thermal treatment near the glass transition temperature. Such bleached films show several guided modes in the visible region and have a high refractive index. Controlled crystallization was realized and thus it was possible to obtain WO3 microcrystals in the amorphous phase. (C) 2007 Elsevier B.V. All rights reserved.