Radiopacity evaluation of new root canal filling materials by digitalization of images

The aim of this study was to evaluate the radiopacity of five root canal filling materials (AH Plus, Intrafill, Roeko Seal, Epiphany, and EndoRez). Following the International Organization of Standardization 687612001, five circular specimens (10 X 1 mm) were made from each material. After the material set, radiographs were made using occlusal film and a graduated aluminum step-wedge varying in thickness from 2 to 16 mm. The dental X-ray unit (GE1000) was set at 50 Kvp, 10 mA, 18 pulses/second, and distance of 33.5 cm. The radiographs were digitized, and the radiopacity was compared with the aluminum step-wedge, using WIXWIN-2000 software (Gendex). Data (mm Al) were analyzed using ANOVA and Tukey tests. AH Plus and Epiphany were the most radiopaque materials (9.8 and 8.8 mm Al, respectively), followed by EndoRez (7.2 mm Al). Roeko Seal and Intrafill presented the lowest radiopacity values (5.7 and 6.1 mm Al, respectively). Although the materials evaluated demonstrated different radiopacities, all had values above the minimum recommended by the international Organization of Standardization.

Bacterial leakage in root canals filled with conventional and MTA-based sealers

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

Evaluation of the propylene glycol association on some physical and chemical properties of mineral trioxide aggregate

Duarte MAH, Alves de Aguiar K, Zeferino MA, Vivan RR, Ordinola-Zapata R, Tanomaru-Filho M, Weckwerth PH, Kuga MC. Evaluation of the propylene glycol association on some physical and chemical properties of mineral trioxide aggregate. International Endodontic Journal, 45, 565570, 2012. Abstract Aim To evaluate the influence of propylene glycol (PG) on the flowability, setting time, pH and calcium ion release of mineral trioxide aggregate (MTA). Methodology Mineral trioxide aggregate was mixed with different proportions of PG, as follows: group 1: MTA + 100% distilled water (DW); group 2: MTA + 80% DW and 20% PG; group 3: MTA + 50% DW and 50% PG; group 4: MTA + 20% DW and 80% PG; group 5: MTA + 100% PG. The ANSI/ADA No. 57 was followed for evaluating the flowability and the setting time was measured by using ASTM C266-08. For pH and calcium release analyses, 50 acrylic teeth with root-end cavities were filled with the materials (n = 10) and individually immersed in flasks containing 10 mL deionized water. After 3 h, 24 h, 72 h and 168 h, teeth were placed in new flasks and the water in which each specimen was immersed had its pH determined by a pH metre and the calcium release measured by an atomic absorption spectrophotometer with a calcium-specific hollow cathode lamp. Data were analysed by using one-way anova test for global comparison and by using Tukeys test for individual comparisons. Results The highest value of flowability was observed with MTA + 20% DW and 80% PG and the lowest values were found with MTA + 100% DW. They were significantly different compared to the other groups (P < 0.05). The presence of PG did not affect the pH and calcium release. The MTA + 100% PG favoured the highest (P < 0.05) pH and calcium release after 3 h. Increasing the PG proportion interfered (P < 0.05) with the setting time; when used at the volume of 100% setting did not occur. Conclusion The addition of PG to MTA-Angelus increased its setting time, improved flowability and increased the pH and calcium ion release during the initial post-mixing periods. The ratio of 80% DW 20% PG is recommended.

Influence of surface sealant on the translucency of composite resin: effect of immersion time and immersion media

This study evaluated the effect of surface sealant on the translucency of composite resin immersed in different solutions. The study involved the following materials: Charisma, Fortify and coffee, Coca-Cola®, tea and artificial saliva as solutions. Sixty-four specimens (n = 8) were manufactured and immersed in artificial saliva at 37 ± 1 °C. Samples were immersed in the solutions for three times a day and re-immersed in artificial saliva until the translucency readings. The measurements were carried out at nine times: T1 - 24 hours after specimen preparation, T2 - 24 hours after immersion in the solutions, T3 - 48 hours and T4 to T9 - 7, 14, 21, 30, 60 and 90 days, respectively, after immersion. The translucency values were measured using a JOUAN device. The results were subjected to ANOVA and Tukey's test at 5%. The surface sealant was not able to protect the composite resin against staining, the coffee showed the strongest staining action, followed by tea and regarding immersion time, a significant alteration was noted in the translucency of composite resin after 21 days.

Controle de fitopatógenos do solo com materiais vegetais associados à solarização

A incorporação de material orgânico associada à solarização do solo é uma técnica promissora no controle de patógenos de plantas. O trabalho consistiu na prospecção de materiais vegetais promissores na produção de voláteis fungitóxicos capazes de inviabilizar as estruturas de resistência de fitopatógenos do solo. em condição de campo foram incorporados 3 Kg/m² de folhas e ramos de brócolos, eucalipto, mamona e mandioca brava, associada ou não à solarização, visando o controle de Fusarium oxysporum f. sp. lycopersici raça 2; Macrophomina phaseolina; Rhizoctonia solani AG-4 HGI e Sclerotium rolfsii. O controle foi avaliado por meio da sobrevivência das estruturas, em meios semi-seletivo específicos, aos 7, 14, 21 e 28 dias do início do experimento. Foram monitoradas as temperaturas do solo e do ar por um DataLogger Tipo CR23X (Campbell Scientific) e a porcentagem de CO2 e de O2 pelo equipamento analisador de gases (Testo 325-1). A associação da incorporação dos materiais vegetais com a solarização do solo inativou F. oxysporum f. sp. lycopersici raça 2, M. phaseolina e R. solani. O fungo S. rolfsii foi o único que não apresentou 100% de controle com solarização mais mamona durante o período estudado. A incorporação de mandioca seguido de solarização propiciou o controle de todos os fungos estudados com menos de sete dias da instalação do experimento, sendo tão eficiente quanto o brócolos na erradicação dos fitopatógenos veiculados pelo sol.

Rotifer abundance, biomass, and secondary production after the recovery of hydrologic connectivity between a river and two marginal lakes (São Paulo, Brazil)

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

Influence of Nb content on the corrosion resistance and saturation magnetic density of FeCuNbSiB alloys

Nanocrystalline FeCuNbSiB alloys obtained from the partial crystallization of amorphous alloys have attracted technological attention due to their excellent magnetic properties, but the relationship between corrosion resistance and magnetic properties is not well established. The influence of Nb as an alloying element and effect of partial crystallization on the corrosion resistance of Fe73.5Si13.5B10Cu1, Fe73.5Si13.5B7Nb3Cu1 and Fe73.5Si13.5B5Nb5Cu1 amorphous alloys were studied and the effect of corrosion on magnetization saturation flux density, B-s, was investigated. The addition of niobium on amorphous alloys increases the corrosion resistance. The raise of Nb content from 3 to 5% increases the corrosion resistance also. A partial crystallization increases the corrosion resistance of the samples with Nb. However, in the samples without Nb, the partial crystallization diminishes the corrosion resistance. The values of B-s depend on the alloy corrosion resistance.) (C) 2002 Elsevier B.V. B.V. All rights reserved.

Composition and structure of fish assemblage from Passa Cinco stream, Corumbataí river sub-basin, SP, Brazil

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

Structure and feeding of a stream fish assemblage in southeastern Brazil: evidence of low seasonal influences

Aim: The present study was developed in a deforested stream located in a region that exhibits marked seasonality with the purpose to investigate whether ecological descriptors of the quantitative structure (i.e., composition, abundance, biomass, species richness, diversity) and feeding of fishes do change between the dry and wet periods. Methods: Sampling was conducted bimonthly from April 2004 to February 2005 by using a standardized effort with electrofishing equipment and environmental variables measurements. Results: We collected 713 fishes belonging to 23 species. The most abundant species were Gymnotus carapo (24.0%) and Poecilia reticulata (23.8%). Species richness, abundance, and biomass showed to be higher in the wet period, but these differences were not significant and did not influence the multivariate pattern of the assemblage (ANOSIM, R = 0.148). Nevertheless, average dissimilarity between community structure in the dry and wet periods was 52.7%, mainly due to the differential contribution of P. reticulata, notably more abundant in the wet season, under quasi-hypoxic water conditions. Examination of 333 gastric contents of 12 species evidenced that food variety was higher in the dry period. of these species, 67% (Astyanax altiparanae, Astyanax fasciatus, Geophagus brasiliensis, Gymnotus carapo, Hypostomus ancistroides, Phalloceros harpagos, Poecilia reticulata, and Rhamdia quelen) kept the diet throughout the year, being classified in the same trophic groups in both periods, and detritus was the most important item for half of them, followed by aquatic insects. Overall, no significant differences in the community's diet between periods were registered (ANOSIM, R = [long dash]0.04). Conclusions: This relative constancy suggests a quite regular availability of resources (mainly shelters in submerged marginal grasses and detritus) along the year.

Ag precipitation and dissolution reactions in the Cu-3 wt.% Al-4 wt.% Ag alloy

The Ag precipitation and dissolution reactions in the Cu-3 wt.% Al-4 wt.% Ag alloy were studied using isothermal and non-isothermal analyses. The activation energy values, obtained for the Ag precipitation reaction indicated that, when the Kissinger, Ozawa and Johnson-MehI-Avrami methods are compared, the Kissinger method is the most appropriate. Although the Johnson-Mehl-Avrami equation often does not fit precipitation data, the energy values obtained for Ag precipitation kinetics are in agreement with what was experimentally observed. For the dissolution reaction of Ag precipitates the activation energy values obtained from the Kissinger and Ozawa methods are higher than that found in the literature for the Ag dissolution in Cu. This discrepancy seems to be related to the fact that the activation energy is influenced by the heating rate. (c) 2006 Elsevier B.V. All rights reserved.

SnO2 nanocrystals synthesized by microwave-assisted hydrothermal method: towards a relationship between structural and optical properties

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Photolumiscent Properties of Nanorods and Nanoplates Y2O3:Eu3+

Nanorods and nanoplates of Y2O3:Eu3+ powders were synthesized through the thermal decomposition of the Y(OH)(3) precursors using a microwave-hydrothermal method in a very short reaction time. These powders were analyzed by X-ray diffraction, field emission scanning electron microscopy, Fourrier transform Raman, as well as photoluminescence measurements. Based on these results, these materials presented nanoplates and nanorods morphologies. The broad emission band between 300 and 440 nm ascribed to the photoluminescence of Y2O3 matrix shifts as the procedure used in the microwave-hydrothermal assisted method changes in the Y2O3:Eu3+ samples. The presence of Eu3+ and the hydrothermal treatment time are responsible for the band shifts in Y2O3:Eu3+ powders, since in the pure Y2O3 matrix this behavior was not observed. Y2O3:Eu3+ powders also show the characteristic Eu3+ emission lines at 580, 591, 610, 651 and 695 nm, when excited at 393 nm. The most intense band at 610 nm is responsible for the Eu3+ red emission in these materials, and the Eu3+ lifetime for this transition presented a slight increase as the time used in the microwave-hydrothermal assisted method increases.

Survival of Ucides cordatus (Decapoda: Ocypodidae) megalopae during transport under different conditions of density and duration

Target areas for Ucides cordatus (Linnaeus, 1763) restocking programs are often located far from the laboratory where larval rearing is developed. During translocation, the larvae are submitted to highly stressful conditions due to handling, packing, and transport activities. The aim of the present study was to assess the mortality rates of U. cordatus megalopae caused by different transportation procedures. Megalopae at loading densities of 50, 150, and 300 ind.L-1 were packed in double polyethylene 12 x 25 cm plastic bags with 200 ml of marine water at salinity 30. The bags were filled with oxygen at a proportion of 1:2 parts of water and sealed tightly. The trepidations during transport were simulated by the use of a shaker device (800 vibrations/minute) over periods of three and six hours inside a dark container. The survivorship rates of larvae after simulation were compared to those obtained in control groups, which consisted of plastic vials with megalopae at a loading density of 50 ind.L-1 maintained at rest. Immediately after the two transport simulations, there was no significant difference in survivorship between the treatments and the control. However, 24 hours after simulation some of the tested densities resulted in significantly lower survivorships. The results demonstrated that U. cordatus megalopae can tolerate six hours of shaking during transportation, at high densities with minimal mortality.

Spray deposition and losses in potato as a function of air-assistance and sprayer boom angle

A cultura da batata possui grande expressão econômica dentro do cenário agrícola. Para isso, equipamentos e técnicas de aplicação de produtos fitossanitários vêm sendo desenvolvidos visando melhorar o rendimento econômico da cultura. Neste sentido, experimentos foram conduzidos no delineamento em blocos ao acaso na cultura da batata cv. Ágata. Objetivando avaliar o efeito da assistência de ar combinada a diferentes ângulos de aplicação sobre a deposição da pulverização, bem como as perdas da calda para o solo utilizou-se um pulverizador com e sem assistência de ar junto à barra de pulverização posicionada a +30º, 0º e -30º (sinal + a favor e - contrário ao deslocamento) em relação a vertical. O volume de calda foi 400 L ha-1 utilizando-se pontas de jato cônico vazio JA-4 na pressão de 633 kPa. Para a avaliação dos depósitos utilizou-se um traçador cúprico. Os depósitos foram removidos dos folíolos por lavagem com água destilada, em ambas as superfícies foliares, nas posições superior e inferior das plantas de batata e quantificados por espectrofotometria de absorção atômica. As perdas da pulverização foram avaliadas em coletores plásticos colocados nas entrelinhas das parcelas experimentais. Os níveis dos depósitos do traçador cúprico nas diferentes posições da planta foram analisados pelo teste estatístico T² de Hotteling. Os maiores depósitos foram obtidos com a barra posicionada a 0º e +30º, em presença da assistência de ar, tanto na posição superior quanto inferior da planta. A presença do ar, além de propiciar maiores depósitos na parte inferior das plantas, possibilitou maior uniformidade na distribuição deles. As perdas da pulverização ficaram abaixo de 4%.

Physical and mechanical properties of ceramics from clays of the west of S. Paulo State, Brazil

Argilas de interesse da indústria de cerâmica estrutural foram caracterizadas. Algumas propriedades físicas de diversas massas cerâmicas, preparadas a partir de material coletado em depósitos artificiais, também foram analisadas. Todas as massas investigadas exibem alta concentração de componentes finos (< 2 mim) e considerável grau de plasticidade, o que é compatível com a presença de elevado teor de argilominerais. Corpos de prova cerâmicos foram preparados por prensagem a seco e queimados em temperaturas ao redor de 855 °C. Os parâmetros resistência mecânica à flexão, retração linear, absorção de água, cor aparente e perda de peso foram medidos. Como resultado, as aplicações industriais destas matérias primas foram analisadas e revistas, bem como novas aplicações foram propostas.