Physicochemical and mechanical properties of zirconium oxide and niobium oxide modified Portland cement-based experimental endodontic sealers

Aim: To evaluate the physicochemical and mechanical properties of Portland cement-based experimental sealers (ES) with different radiopacifying agents (zirconium oxide and niobium oxide micro- and nanoparticles) in comparison with the following conventional sealers: AH Plus, MTA Fillapex and Sealapex. Methodology: The materials were tested for setting time, compressive strength, flow, film thickness, radiopacity, solubility, dimensional stability and formaldehyde release. Data were subjected to anova and Tukey tests (P < 0.05). Results: MTA Fillapex had the shortest setting time and lowest compressive strength values (P < 0.05) compared with the other materials. The ES had flow values similar to the conventional materials, but higher film thickness (P < 0.05) and lower radiopacity (P < 0.05). Similarly to AH Plus, the ES were associated with dimensional expansion (P > 0.05) and lower solubility when compared with MTA Fillapex and Sealapex (P < 0.05). None of the endodontic sealers evaluated released formaldehyde after mixing. Conclusion: With the exception of radiopacity, the Portland cement-based experimental endodontic sealers presented physicochemical properties according to the specifications no 57 ANSI/ADA (ADA Professional Product Review, 2008) and ISO 6876 (Dentistry - Root Canal Sealing Materials, 2012, British Standards Institution, London, UK). The sealers had setting times and flow ability that was adequate for clinical use, satisfactory compressive strength and low solubility. Additional studies should be carried out with the purpose of decreasing the film thickness and to determine the ideal ratio of radiopacifying agents in Portland cement-based root canal sealers. © 2013 International Endodontic Journal.

Fish exposure to nano-TiO2 under different experimental conditions: Methodological aspects for nanoecotoxicology investigations

The ecotoxicology of nano-TiO2 has been extensively studied in recent years; however, few toxicological investigations have considered the photocatalytic properties of the substance, which can increase its toxicity to aquatic biota. The aim of this work was to evaluate the effects on fish exposed to different nano-TiO2 concentrations and illumination conditions. The interaction of these variables was investigated by observing the survival of the organisms, together with biomarkers of biochemical and genetic alterations. Fish (Piaractus mesopotamicus) were exposed for 96h to 0, 1, 10, and 100mg/L of nano-TiO2, under visible light, and visible light with ultraviolet (UV) light (22.47J/cm2/h). The following biomarkers of oxidative stress were monitored in the liver: concentrations of lipid hydroperoxide and carbonylated protein, and specific activities of superoxide dismutase, catalase, and glutathione S-transferase. Other biomarkers of physiological function were also studied: the specific activities of acid phosphatase and Na,K-ATPase were analyzed in the liver and brain, respectively, and the concentration of metallothionein was measured in the gills. In addition, micronucleus and comet assays were performed with blood as genotoxic biomarkers. Nano-TiO2 caused no mortality under any of the conditions tested, but induced sublethal effects that were influenced by illumination condition. Under both illumination conditions tested, exposure to 100mg/L showed an inhibition of acid phosphatase activity. Under visible light, there was an increase in metallothionein level in fish exposed to 1mg/L of nano-TiO2. Under UV light, protein carbonylation was reduced in groups exposed to 1 and 10mg/L, while nucleus alterations in erythrocytes were higher in fish exposed to 10mg/L. As well as improving the understanding of nano-TiO2 toxicity, the findings demonstrated the importance of considering the experimental conditions in nanoecotoxicological tests. This work provides information for the development of protocols to study substances whose toxicity is affected by illumination conditions. © 2013 Elsevier B.V..

Ecotoxicidade e eficácia da oxitetraciclina e do florfenicol contra infecção experimental por Aeromonas hydrophila e aspectos histopatológicos em pacu (Piaractus mesopotamicus)

Pós-graduação em Aquicultura - FCAV

Análise teórica e experimental de um método interferométrico de detecção de fase óptica, auto-consistente e com elevada faixa dinâmica, aplicado à caracterização de atuadores piezoelétricos flextensionais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Proposta de modelo experimental para o estudo da síndrome metabólica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo experimental da interação fluido-estrutura no escoamento em um difusor radial

Pós-graduação em Engenharia Mecânica - FEIS

Estudo experimental do escoamento em cavidades abertas utilizando um canal de superfície livre

Pós-graduação em Engenharia Mecânica - FEIS

Estudo experimental do escoamento em cavidades retangulares: padrões de escoamento e instabilidades hidrodinâmicas na camada cisalhante

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de um circuito eletrônico experimental de anemômetro de fio quente

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da tromboflebite jugular experimental em equinos tratados com heparina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dessensibilização dos nervos palmares em eqüinos: estudo comparativo experimental do álcool benzílico 0,75% e álcool etílico absoluto (95,5% PA)

Pós-graduação em Medicina Veterinária - FMVZ

Intoxicação experimental de cães com sementes de Crotalaria spectabilis (Leg. Papilionoideae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo clínico, laboratorial e terapêutico da diarréia experimental em bezerros induzida por Salmonella enterica subespécie Enterica sorotipo typhimurium

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

Infecção experimental por Salmonella enterica subspécie enterica sorotipo Panama e tentativa de transmissão área em leitões desmamados

Pós-graduação em Medicina Veterinária - FCAV

Indução experimental de polioencefalomalacia em ovinos confinados ingerindo dieta com alto teor de enxofre

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