Preparation, microstructural and electrical characterization of SrTiO3 thin films prepared by chemical route

Polycrystalline SrTiO3 thin films having a cubic perovskite structure were prepared at different temperatures by the polymeric precursor method on platinum-coated silicon substrate. Crystalline films with uniform composition and thickness were prepared by spin-coating and the post-deposition heat treatment was carried out at different temperatures. The film showed good structural, dielectric, and insulating properties, Scanning electron microscopy (SEM) micrographs showed no occurrence of interdiffusion between the bottom electrode (platinum) and the film during post-annealing, indicating a stable interface between the SrTiO3 and the bottom electrode. The dielectric constant and dissipation factor at a frequency of 100 kHz were 250 and 0.01, respectively, for a 360 nm thick film annealed at 600 degreesC. The capacitance versus applied voltage characteristics showed that the capacitance was almost independent of the applied voltage. The I-V characteristics were ohmic in low fields and a Schottky emission and/or Poole-Frenkel emission were postulated in high fields. Room temperature leakage current density was found to be in the order of 10(-7) A/cm(2) for a 360 nm thick film in an applied electric field of about 100 kV/cm. The charge storage density of 36 fC/mum(2) was obtained in an applied electric field of about 100 kV/cm. (C) 2001 Published by Elsevier B.V. Ltd. All rights reserved.

Stable colloidal suspensions of nanostructured zirconium oxide synthesized by hydrothermal process

Funda��ão de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal analysis applied in the crystallization study of SrSnO3

SrSnO3 was synthesized by the polymeric precursor method with elimination of carbon in oxygen atmosphere at 250 A degrees C for 24 h. The powder precursors were characterized by TG/DTA and high temperature X-ray diffraction (HTXRD). After calcination at 500, 600 and 700 A degrees C for 2 h, samples were evaluated by X-ray diffraction (XRD), infrared spectroscopy (IR) and Rietveld refinement of the XRD patterns for samples calcined at 900, 1,000 and 1,100 A degrees C. During thermal treatment of the powder precursor ester combustion was followed by carbonate decomposition and perovskite crystallization. No phase transition was observed as usually presented in literature for SrSnO3 that had only a rearrangement of SnO6 polyhedra.

Effect of diclofenac sodium on the healing process of end-to-end anastomosis in carotid arteries of rabbits. Histopathological and biomechanical studies

Aim. Diclofenac sodium is a non-steroidal anti-inflammatory drug commonly used to attenuate painful inflammatory reactions in surgery. However, it may delay healing in the skin and gastrointestinal tract. The aim of this study was to evaluate the influence of Diclofenac in vascular healing. Methods. Ninety rabbits had their carotid arteries sectioned and reconstructed by end-to-end anastomosis with interrupted sutures. The animals were randomly allocated into 3 groups of 30 each and treated by intramuscular route with saline (control), 5 mg/kg/day of diclofenac sodium (DS-5), and 10 mg/kg/day of diclofenac sodium (DS-10). Treatment began on the day of surgery and lasted 4 days. Angiography, biomechanical properties (failure load, failure elongation, yield point, yield point elongation, and stiffness were obtained from the load/elongation curve), macroscopic and histological examinations (hematoxylin-eosin, Masson, Calleja, Picrossirius-red), and scanning electron microscopy were studied in both arteries on the 3rd and 15th postoperative days. Results. No significant differences in biomechanical properties were observed either in the 3 groups or the experimental times. The carotid artery healing process was similar in the 3 groups. Conclusion. Diclofenac sodium did not cause alterations nor delayed carotid artery healing.

Condutividade elétrica e polariza��ão térmica de vidros soda-cal-sílica contendo diferentes c��tions tetravalentes

Funda��ão de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos de antioxidantes e da atmosfera gasosa em diferentes etapas da produção in vitro sobre o desenvolvimento e criotolerância de embriões bovinos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Implicações do perfil de ansiedade na dinâmica

Pós-gradua��ão em Ciências Biológicas (Zoologia) - IBB

Soroepidemiologia de Chlamydia trachomatis, Chlamydia pneumoniae e Treponema pallidum nas aldeias indígenas Bakajá, Apyterewa, Xingu e Mrotidjãm, Altamira, Pará, Brasil

As bactérias do gênero Chlamydia estão associadas à diversas doenças, como cegueira, infec��ões genitais e pneumonia. Existem poucos dados sobre como a Chlamydia e o Treponema pallidum afetam indígenas na Amazônia brasileira. Este estudo objetivou determinar a soroprevalência das infec��ões pela Chlamydia trachomatis, Chlamydia pneumoniae e Treponema pallidum nas aldeias indígenas Bakajá, Apyterewa, Xingu e Mrotdidjãm, no munic��pio de Altamira, Pará, Brasil. O estudo incluiu 270 amostras de sangue coletadas no ano de 2007. A detec��ão de anticorpos das classes IgM e IgG anti-Chlamydia foi realizada empregando-se o ensaio imunoenzimático (ELISA), e selecionada de forma aleatória amostragem de 36, entre os positivos, para determinar a sorotipagem pela microimunofluoresc��ncia. Para detec��ão de anticorpos anti-T. pallidum foi utilizado um teste treponêmico (ELISA) e as amostras positivas foram submetidas a um teste não treponêmico (RPR). A prevalência geral de anticorpos anti-Chlamydia foi de 26,7%, com prevalência de 100% para C. trachomatis entre as amostras testadas pela MIF. Para a C. pneumoniae a prevalência foi de 61,1% e a prevalência de anticorpos contra Treponema pallidum foi baixa. As bactérias do estudo circulam nas comunidades indígenas da Amazônia brasileira estudada, o que requer uma resposta urgente das autoridades de sa��de pública, pois estas bactérias podem causar doenças graves, mas são sensíveis a tratamento espec��fico, quando diagnosticadas adequadamente.

Soroepidemiologia de Chlamydia trachomatis, Chlamydia pneumoniae e Treponema pallidum em portadores do Vírus da imunodeficiência humana (HIV), no Estado do Pará

A Chlamydia trachomatis e o Treponema pallidum compartilham com o HIV uma importante forma de transmissão: a via sexual. Por conta do comprometimento imunológico dos portadores de HIV, a C. pneumoniae pode apresentar um papel potencial em infec��ões respiratórias. Este trabalho objetivou a descrição da soroprevalência destes três agentes em portadores de HIV do Estado do Pará, Brasil. Entre setembro de 2007 a junho de 2008, foram coletadas 430 amostras de portadores de HIV em Belém, Pará. Estas foram submetidas a um ELISA para detec��ão de anticorpo IgG e IgM anti-Chlamydia e, dentre os positivos, uma amostragem aleatória foi escolhida e submetida à microimunofluoresc��ncia para sorotipagem. Para a detec��ão de anticorpos anti-Treponema pallidum foi feito um teste não treponêmico (RPR) e um teste treponêmico (ELISA). Os resultados obtidos foram analisados pelo teste do χ². A prevalência geral de anticorpos anti-Chlamydia foi 64,2% (51,6% para IgG e 4% para IgM). A sorotipagem mostrou uma alta prevalência de C. trachomatis (100% tanto para IgG como IgM), e C. pneumoniae (73,5% IgG e 70,5% IgM), sendo que houve uma larga dissemina��ão dos sorotipos que causam infec��ões genitais da Chlamydia trachomatis. A prevalência geral de anticorpos contra o Treponema pallidum foi de 34,9%, sendo que 7,3% apresentaram resultado laboratorial indicativo de sífilis. As variáveis que apresentaram associa��ão com a infec��ão por Chlamydia e Treponema pallidum foram: o gênero masculino, maior idade, baixa escolaridade, número de parceiros por semana, a prática de sexo anal, homossexualismo/bissexualismo, uso de droga não-endovenosa, histórico de IST. Faz-se necessário tanto a conscientiza��ão como o monitoramento da popula��ão, para impedir a transmissão destes agentes e para a melhoria da qualidade de vida dos indivíduos portadores de HIV.

The antimicrobial effects of Citrus limonum and Citrus aurantium essential oils on multi-species biofilms

The aim of this study was to evaluate the effects of Citrus limonum and Citrus aurantium essential oils (EOs) compared to 0.2% chlorhexidine (CHX) and 1% sodium hypochlorite (NaOCl) on multi-species biofilms formed by Candida albicans, Enterococcus faecalis and Escherichia coli. The biofilms were grown in acrylic disks immersed in broth, inoculated with microbial suspension (106 cells/mL) and incubated at 37°C / 48 h. After the biofilms were formed, they were exposed for 5 minutes to the solutions (n = 10): C. aurantium EO, C. limonum EO, 0.2% CHX, 1% NaOCl or sterile saline solution [0.9% sodium chloride (NaCl)]. Next, the discs were placed in sterile 0.9% NaCl and sonicated to disperse the biofilms. Tenfold serial dilutions were performed and the aliquots were seeded onto selective agar and incubated at 37°C / 48 h. Next, the number of colony-forming units per milliliter was counted and analyzed statistically (Tukey test, p ≤ 0.05). C. aurantium EO and NaOCl inhibited the growth of all microorganisms in multi-species biofilms. C. limonum EO promoted a 100% reduction of C. albicans and E. coli, and 49.3% of E. faecalis. CHX was less effective against C. albicans and E. coli, yielding a reduction of 68.8% and 86.7%, respectively. However, the reduction of E. faecalis using CHX (81.7%) was greater than that obtained using C. limonum EO. Both Citrus limonum and Citrus aurantium EOs are effective in controlling multi-species biofilms; the microbial reductions achieved by EOs were not only similar to those of NaOCl, but even higher than those achieved by CHX, in some cases.

Accuracy of genomic predictions in Bos indicus (Nellore) cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparative anatomy of reproductive structures in Cyclanthaceae (Pandanales)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Parâmetros oftálmicos em espécimes de Cuniculus paca criadas em cativeiro

Pós-gradua��ão em Cirurgia Veterinária - FCAV

Atividade antimicrobiana de enxaguatórios bucais sem álcool à base de clorexidina sobre candida albicans

The aim of this study was to evaluate the antimicrobial activity of alcohol-free mouthwashes on Candida albicans. Twenty clinical isolates of C. albicans and one reference strain (ATCC 18804) were evaluated after exposure to two 0.12% chlorhexidine-based and alcohol-free (“Ca” and “Or”) in comparison to gluconate chlorhexidine with ethanol (positive control). The maximum inhibitory dilution (MID) and maximum fugal dilution (MFD) were determined by the microdilution method. Twelve serial dilutions (from 50 to 0.02%) were prepared in duplicate. Then, 100 µL of C. albicans suspension (106 cells.mL–1) were added to the wells. After incubation (37 °C/24 hours), MID was determined by reading the optical density. For MFD determination, the content of the wells were plated on Saouraud agar. For MID, there were no differences between groups Or and control, but Ca group showed a MID statistically higher (Kruskal-Wallis, p = 0.0012). For MFD, there were no differences between Ca and control (Mann-Whitney test, p = 0.1631). It can be concluded that Ca group showed a fungicid activity against C. albicans similar to the control, but lower fungistatic activity when compared to the control. Group Or showed only a fungistatic action similar to control.

Estresse térmico no acúmulo de prolina livre de plântulas de guandu oriundas de sementes tratadas com poliaminas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)