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Avaliação in vitro de propriedades mecânicas, químicas e antimicrobianas de um selante de fossas e fissuras isento de bisfenol A; In vitro evaluation of mechanical, chemical and antimicrobial properties of a bisphenol A-free pit-and-fissure sealant

Aguiar, Soraia Monique Fiorati
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 21/05/2010 PT
Relevância na Pesquisa
919.0066%
Tendo em vista o importante papel desempenhado pelos selantes de fossas e fissuras na prevenção da cárie dental, o objetivo do presente estudo foi avaliar in vitro propriedades mecânicas, químicas e ntimicrobianas do selante isento de bisfenol A Embrace Wetbond™. Para os testes de resistência ao cisalhamento e microinfiltração foram selecionados 135 terceiros molares hígidos, extraídos de humanos, divididos aleatoriamente em 6 grupos: (I) selante Fluroshield® sem contaminação; (II) selante Embrace Wetbond™ sem contaminação; (III) selante Fluroshield® contaminado com saliva; (IV) selante Embrace Wetbond™ contaminado com saliva; (V) selante Fluroshield® contaminado com água; e (VI) selante Embrace Wetbond™ contaminado com água. No estudo de resistência ao cisalhamento os dentes foram seccionados no sentido vestíbulo-lingual, a porção radicular removida e as superfícies mesiais e distais foram embebidas em resina de poliéster. Após o condicionamento do esmalte, foi aplicado o selante com o auxílio de uma matriz de Teflon®. Os espécimes foram termociclados e submetidos ao teste de resistência ao cisalhamento com uma velocidade de 0,5mm/min e célula de carga de 50kgf. Os resultados foram comparados empregando a análise de variância (ANOVA) e pós-teste de Tukey. No estudo de microinfiltração...

Importance of dosage standardization for interpreting transcriptomal signature profiles: Evidence from studies of xenoestrogens

Shioda, Toshi; Chesnes, Jessica; Coser, Kathryn R.; Zou, Lihua; Hur, Jingyung; Dean, Kathleen L.; Sonnenschein, Carlos; Soto, Ana M.; Isselbacher, Kurt J.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
400.18527%
To obtain insights into similarities and differences in the biological actions of related drugs or toxic agents, their transcriptomal signature profiles (TSPs) have been examined in a large number of studies. However, many such reports did not provide proper justification for the dosage criteria of each agent. Using a well characterized cell culture model of estrogen-dependent proliferation of MCF7 human breast cancer cells, we demonstrate how different approaches to dosage standardization exert critical influences on TSPs, leading to different and even conflicting conclusions. Using quantitative cellular response (QCR)-based dosage criteria, TSPs were determined by Affymetrix microarray when cells were proliferating at comparable rates in the presence of various estrogens. We observed that TSPs of the xenoestrogens (e.g., genistein or bisphenol A) were clearly different from the TSP of 17β-estradiol; namely, the former strongly enhanced expression of genes involved in mitochondrial oxidative phosphorylation, whereas the latter showed minimal effects. In contrast, TSPs for genistein and 17β-estradiol were indistinguishable by using the marker gene expression-based dosage criteria, conditions in which there was comparable expression of the mRNA transcripts for the estrogen-inducible WISP2 gene. Our findings indicate that determination and interpretation of TSPs in pharmacogenomic and toxicogenomic studies that examine the transcriptomal actions of related agents by microarray require a clear rationale for the dosage standardization method to be used. We suggest that future studies involving TSP analyses use quantitative and objective dosage standardization methods...

Synthesis of BiOI-TiO2 Composite Nanoparticles by Microemulsion Method and Study on Their Photocatalytic Activities

Chen, Yunfang; Xu, Xiaoxin; Fang, Jianzhang; Zhou, Guangying; Liu, Zhang; Wu, Shuxing; Xu, Weicheng; Chu, Jinhui; Zhu, Ximiao
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Publicado em 16/01/2014 EN
Relevância na Pesquisa
288.53115%
This study was conducted to synthesize a series of nanosized BiOI-TiO2 catalysts to photodegrade Bisphenol A solution. The BiOI-TiO2 nanoparticles were synthesized in the reverse microemulsions, consisting of cyclohexane, Triton X-100, n-hexanol, and aqueous salt solutions. The synthesized particles were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface analyzer, Fourier transform-infrared spectroscopy (FT-IR), ultraviolet-visible light (UV-Vis) absorption spectra and transmission electron microscope (TEM). The photodegradation of Bisphenol A (BPA) in aqueous suspension under visible light irradiation was investigated to explore the feasibility of using the photocatalytic method to treat BPA wastewater. The effects of different molar ratios of BiOI to TiO2 on the photocatalytic activity were discussed. The experimental results revealed that the photocatalytic effect of the BiOI-TiO2 particles was superior to the commercial P25 TiO2. The BPA degradation could be approached by a pseudo-first-order rate expression. The observed reaction rate constant (kobs) was related to nanoparticles dosage and initial solution pH.