Crystallographic, dielectric and optical properties of SrBi2Ta2O9 thin films prepared by the polymeric precursor method

Strontium bismuth tantalate thin films were prepared on several substrates (platinized silicon (PvTi/SiO2/Si), n-type (100)-oriented and p-type (111)-oriented silicon wafers, and fused silica) by the solution deposition method. The resin was obtained by the polymeric precursor method, based on the Pechini process, using strontium carbonate, bismuth oxide, and tantalum ethoxide as starting reagents. Characterizations by XRD and SEM were performed for structural and microstructural evaluations. The electrical measurements, carried on the MFM configuration, showed P-r values of 6.24 muC/cm(2) and 31.5 kV/cm for the film annealed at 800 degreesC. The film deposited onto fused silica and treated at 700 degreesC presented around 80 % of transmittance.

Crystallographic, dielectric and optical properties of SrBi 2Ta2O9 thin films prepared by the polymeric precursor method

Strontium bismuth tantalate thin films were prepared on several substrates (platinized silicon (Pt/Ti/SiO 2 /Si), n -type (100)-oriented and p -type (111)-oriented silicon wafers, and fused silica) by the solution deposition method. The resin was obtained by the polymeric precursor method, based on the Pechini process, using strontium carbonate, bismuth oxide, and tantalum ethoxide as starting reagents. Characterizations by XRD and SEM were performed for structural and microstructural evaluations. The electrical measurements, carried on the MFM configuration, showed P r values of 6.24 μC/cm 2 and 31.5 kV/cm for the film annealed at 800 C. The film deposited onto fused silica and treated at 700 C presented around 80% of transmittance. © 2002 Taylor & Francis.

Ferroelectric and microstructural characteristics of SrBi2Ta2O9 thin films crystallized by the rapid thermal annealing process

Ferroelectric SrBi2Ta2O9 thin films on Pt/Ti/SiO2/Si were successfully synthesized by the modified polymeric precursor method. The films were deposited by spin coating and crystallized by rapid thermal annealing in a halogen lamp furnace, followed by postannealing at temperatures ranging from 700 degreesC to 800 degreesC in an oxygen atmosphere. Microstructural and phase evaluations were followed by x-ray diffraction and atomic force microscopy. The films displayed spherical grain structures with a superficial roughness of approximately 3-6 nm. The dielectric constant values were 121 and 248 for films treated at 700 degreesC and 800 degreesC, respectively. The P-E curve showed a voltage shift toward the positive side, which was attributed to crystallization under the halogen illumination. The remanent polarization (2P(r)) and coercive field (E-c) were 7.1 muC/cm(2) and 113 kV/cm, and 18.8 muC/cm(2) and 93 kV/cm for the films treated at 700 degreesC and 800 degreesC, respectively. (C) 2001 American Institute of Physics.

Macro- and microstructural organization of the rabbit's celiac-mesenteric ganglion complex (Oryctolagus cuniculus)

The macro- and microstructures of the rabbit celiac-mesenteric ganglion complex are described in 20 young animals. We found ten celiac ganglia, twenty-seven cranial mesenteric ganglia and eleven celiac-mesenteric ganglia. The celiac ganglia had a rectangular shape in nine cases (90%) and a circular one in one case (10%). The cranial mesenteric ganglia presented triangular (66.7%), rectangular (11.1%), L-shape (18.5%) and semilunar (3.7%) arrangements. The celiac-mesenteric ganglia were organized in three patterns: a single left celiac-mesenteric ganglion having a caudal portion (72.7%); celiac-mesenteric ganglia without a caudal portion (18.2%) and a single celiac-mesenteric ganglion with two portions: left and right (9.1%).The microstructure was investigated in nine celiac-mesenteric ganglia. The results showed that the celiac-mesenteric ganglion is actually a ganglion complex constituted of an agglomerate of ganglionic units separated by nerve fibers, capillaries and septa of connective tissue. Using the semi-thin section method we described the cellular organization of the celiac-mesenteric ganglion complex. Inside of each ganglionic unit, there were various cell types: principal ganglion neurons (PGN), glial cells (satellite cells) and SIF cells (small intensely fluorescent cells or small granular cells), which are the cytologic basis for each ganglionic unit of the rabbit's celiac-mesenteric ganglion complex.

Microstructural and electrochemical study of La0.5Li0.5TiO3

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

Polymeric precursor method to the synthesis of XWO(4) (X = Ca and Sr) thin films-Structural, microstructural and spectroscopic investigations

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

Evaluation of the effect of the stoichiometric ratio of Ca/Cu on the electrical and microstructural properties of the CaCu3Ti4O12 polycrystalline system

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

Influence of vanadium on electrical and microstructural properties of CaCu3Ti4O12/CaTiO3

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Microstructural Characterization of Ti-6Al-7Nb Alloy After Severe Plastic Deformation

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

Microstructural Evolution of Ti-6Al-7Nb Alloy During High Pressure Torsion

Ti-6Al-7Nb alloys are being evaluated for biomedical applications, in substitution of the more conventional Ti-6Al-7V. Both types of alloys present a microstructure containing the alpha and the beta phases, which result in good compromise for mechanical applications. In the present work Ti-6Al-7Nb alloys were processed by High Pressure Torsion (HPT), varying the number of revolutions and thus the total imposed strain. X-Ray Diffraction (XRD) results revealed the formation of different crystallographic textures in samples subjected to HPT. Microhardness distribution, across the diameters of the disks, is rather homogeneous for all samples, with higher values for those subjected to 03 and 05 turns. Transmission electron microscopy (TEM) micrographs have showed that an ultra-fine grained microstructure was obtained in all the samples.

Cocaine mutagenicity and hepatocarcinogenicity evaluations in rodents

The mutagenicity (clastogenicity) and the carcinogenicity (promoting potential) of cocaine were evaluated, respectively, by the mouse bone marrow micronucleus test (study I) and by the initiated rat liver bioassay (study II). In study I, two administration routes (i.p. and i.v.) and two sampling times (24 and 48 hours) after cocaine treatment were studied. Swiss male mice were treated with cocaine at doses of 0, 18, 37, and 75 mg/kg and 0, 2, 4, and 8 mg/kg by i.p. and i.v. routes, respectively. No significant differences were observed between treated and negative control groups regarding the frequencies of micronuclei and the polichromatic/normochromatic erythrocyte (PCE/NCE) ratios. In study II, the development of putative preneoplastic foci of hepatocytes expressing the enzyme glutathione S-transferase placental form (GST-P+) was utilized as the end-point marker in a 8-week rat liver bioassay. The animals were initiated for carcinogenesis by a single i.p. sub-carcinogenic dose of diethylnitrosamine (DEN). After a 6-week exposure to 5 or 10 mg/kg of cocaine i.v. twice a week there was no enhancement of GST-P+ foci development above the values of the control DEN-only treated animals. Also, cocaine did not induce any toxicity as evidenced by the absence of alterations of rat body and liver weights and of liver biochemical function and morphology. The results suggest that cocaine does not have a mutagenic effect on the mouse bone marrow cells or promoting activity on the rat hepatocarcinogenesis process. Teratogenesis Carcinog. Mutagen. 18:199-208, 1998. (C) 1998 Wiley-Liss, Inc.

Comparison of pelvic floor muscle strength evaluations in nulliparous and primiparous women: a prospective study

OBJECTIVE: This study aimed to compare the pelvic floor muscle strength of nulliparous and primiparous women.METHODS: A total of 100 women were prospectively distributed into two groups: Group 1 (G1) (n = 50) included healthy nulliparous women, and Group 2 (G2) (n = 50) included healthy primiparous women. Pelvic floor muscle strength was subjectively evaluated using transvaginal digital palpation. Pelvic floor muscle strength was objectively assessed using a portable perineometer. All of the parameters were evaluated simultaneously in G1 and were evaluated in G2 during the 20(th) and 36(th) weeks of pregnancy and 45 days after delivery.RESULTS: In G2, 14 women were excluded because they left the study before the follow-up evaluation. The median age was 23 years in G1 and 22 years in G2; there was no significant difference between the groups. The average body mass index was 21.7 kg/m(2) in G1 and 25.0 kg/m(2) in G2; there was a significant difference between the groups (p = 0.0004). In G2, transvaginal digital palpation evaluation showed significant impairments of pelvic floor muscle strength at the 36(th) week of pregnancy (p = 0.0006) and 45 days after vaginal delivery (p = 0.0001) compared to G1. Objective evaluations of pelvic floor muscle strength in G2 revealed a significant decrease 45 days after vaginal delivery compared to nulliparous patients.CONCLUSION: Pregnancy and vaginal delivery may cause weakness of the pelvic floor muscles.

Clinical and Microbiologic Follow-Up Evaluations After Non-Surgical Periodontal Treatment With Erbium:YAG Laser and Scaling and Root Planing

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aging effects on the mongolian gerbil female prostate (Skene's paraurethral glands): Structural, ultrastructural, quantitative, and hormonal evaluations

Different from the classic view, the prostate is not a gland exclusive to the male, also being an organ of the female genital system presenting morphofunctional similarity between human and rodent. Thus structural, ultrastructural, morphometric-stereological features of the female prostate (Skene's paraurethral gland) and steroid serological levels were evaluated during young, adult, and senile ages in the Mongolian gerbil. The morphofunctional precocity of the female gland in comparison with the male gland occurring in young gland is probably associated with the female circulating steroid levels. The hormonal imbalance in senesce coincides with its susceptibility to histopathological lesions, such as epithelial hypertrophy, metaplasia, and intraepithelial neoplasia. Differently than that of males, the aging degeneration of the female gland involves the accumulation of lipofuscin granules. However, the alterations in senile prostate did not damage its functionality. These analyses reinforce the use of this experimental model for the comprehension of glandular morphofunctional aspects with special attention to senescence. Thus, the appreciation of this organ becomes relevant to avoid future discomfort to women's health.