Evaluation of screw loosening on new abutment screws and after successive tightening

This study evaluated the loss of the torque applied after use of new screws and after successive tightening. Four infrastructures (IE), using UCLA castable abutment type, were cast in cobalt-chromium alloy and new abutment screws (G1) were used in a first moment. Subsequently, the same abutment screws were used a second time (G2) and more than two times (G3). The values of the torques applied and detorques were measured with a digital torque wrench to obtain the values of initial tightening loss (%). Data were analyzed by ANOVA and Tukey's test (?=0.05). Significant differences were observed between the G1 (50.71% ± 11.36) and G2 (24.01% ± 3.33) (p=0.000) and between G1 (50.71% ± 11.36) and G3 (25.60% ± 4.64) (p=0.000). There was no significant difference between G2 and G3 (p=0.774). Within the limitations of the study, it may be concluded that the percentage of the initial torque loss is lower when screws that already suffered the application of an initial torque were used, remaining stable after application of successive torques.

Tissue inflammatory response to implantation of calcium hydroxide and iodoform in the back of rats

PURPOSE: This study evaluated the inflammatory reaction caused by the implantation of iodoform and calcium hydroxide in the back of rats. These drugs may be used as intracanal dressings to eliminate residual bacteria of the root canal system. METHODS: Twenty albinic rats (Rattus norvegicus, var Wistar) were divided into four groups: control group 1 (CG1) had normal skin; control group 2 (CG2) had wounded tissue without drugs; in groups 3 and 4, iodoform (IG) and calcium hydroxide (CHG) were inserted into the wounds, respectively. After 3, 5 and 11 days, slices of the implanted areas were macroscopically and microscopically observed regarding to their qualitative and quantitative aspects. RESULTS: In the macroscopical analysis, the CHG showed a large area of necrosis and swelling, which progressively decreased; in the IG the presence of iodoform surrounded by normal tissue was observed. The qualitative and quantitative histological analysis showed that IG promoted a shorter delay in the inflammatory response than the CHG. CONCLUSION: The inflammatory reaction for iodoform had a peak period five days after the drug insertion. By comparison, calcium hydroxide showed a very large area of necrosis that could only be partially eliminated after eleven days.

Resposta em parâmetros sanguíneos e urinários de vacas leiteiras ao aumento no balanço cátion-aniônico da dieta

Estudou-se efeito de quatro níveis de dietas catiônicas sobre os parâmetros ácido-base do sangue e o pH urinário de vacas em lactação. Para a manipulação dos níveis do balanço cátion-amônico da dieta (BCAD), foram adicionadas diferentes concentrações de bicarbonato de sódio às dietas, obtendo-se os seguintes tratamentos: +150, +250, +400 e +500mEq/kg de matéria seca. O experimento foi realizado durante o verão, por um período total de 72 dias, utilizando-se oito vacas da raça Holandesa após o pico de lactação, distribuídas em quadrado latino (4x4), replicado, em que cada período teve duração de 18 dias. O pH urinário e o bicarbonato, o pH, o CO2 total e a pCO2 do sangue aumentaram linearmente (P<0,01) com o aumento do BCAD. As concentrações de sódio e potássio do sangue não foram modificadas (P>0,05) pelo BCAD. A concentração de cloro no sangue diminuiu linearmente (P<0,01) com o aumento do BCAD. O aumento do BCAD afetou o equilíbrio ácido-base das vacas, promovendo efeito alcalinogênico, o que poderia levar a diferenças significativas no desempenho do animal.

Effect of Potato virus X on total phenol and alkaloid contents in Datura stramonium leaves

The present paper reports results of the effect of Potato virus X (PVX) on the contents of total phenols and alkaloids in leaves of Datura stramonium. A significant decrease in the contents of phenols and alkaloids was observed in leaves inoculated with PVX (X-I). However, there was an increase in the percentage of phenols in leaves rubbed with phosphate buffer (C1-I) and in leaves from the nodes immediately above, possibly induced by mechanical injury. Gas chromatography/mass spectroscopy revealed amounts of scopolamine in samples submitted to all treatments, except X-I, in which the amount of this alkaloid was low. High amounts of an unidentified compound (molecular ion m/z 302 and a prominent peak at m/z 129) were noted in extracts from leaves X-I, C1-I and leaves from the nodes immediately above the leaves inoculated with PVX. It is suggested that the synthesis and accumulation of the unidentified compound is a result of stress from mechanical injury and virus inoculation.

Gametogenesis in Madracis decactis Lyman, 1859 (Cnidaria, Scleractinia) from Ilha Grande Bay (Rio de Janeiro), southeastern Brazil

Collections were made every two months in Ilha Grande Bay, Rio de Janeiro, for 21 months (August/2004-May/2006) to study the gametogenesis of Madracis decactis Lyman, 1859. A total of 1800 polyps were examined using standard histological techniques. Madracis decactis is a hermaphroditic species whose male and female gametes develop within different mesenteries. Oogenesis begins in October, while spermatogenesis begins at the end of February, both reaching maturity at the end of April. The peak of reproductive activity occurred between February and April, when all the polyps were fertile, containing mainly stage III oocytes. Examination of fertile polyps indicated the simultaneous presence of stages I, II and III for oogenesis and I, II, III and IV for spermatogenesis. No embryos or planulae were observed in the histological sections. The gametes or planulae spawning may occur between April and May.

Anfíbios da Estação Ecológica Serra Geral do Tocantins, região do Jalapão, Estados do Tocantins e Bahia

A porção norte do domínio do Cerrado é uma das áreas historicamente menos conhecidas com relação à sua biodiversidade. Recentemente, alguns estudos tem revelado valores de riqueza comparáveis a outras regiões dentro do domínio. A Estação Ecológica Serra Geral do Tocantins (EESGT) está localizada na região do Jalapão, porção Nordeste do Cerrado, e faz parte do maior bloco de áreas protegidas neste domínio. Neste estudo descrevemos a riqueza e composição de espécies de anfíbios da EESGT, discutindo-as em um contexto biogeográfico, e caracterizamos o uso de sítios reprodutivos pelas espécies de anfíbios registradas em relação às fitofisionomias e aos tipos de corpos d'água. Utilizamos os métodos de busca ativa e armadilhas de queda, no período considerado como o auge da estação reprodutiva para a maior parte das espécies do Cerrado. Foram registradas 36 espécies de anfíbios na EESGT, totalizando 39 espécies conhecidas para a região do Jalapão. Aplicando o estimador Jackknife, sugerimos uma riqueza potencial de 42 espécies para a EESGT. A maior parte das espécies registradas é endêmica ou fortemente associada ao Cerrado, seguidas pelas espécies de ampla distribuição no Brasil ou América do Sul. A maior parte da espécies se reproduz em poças temporárias localizadas em áreas abertas, embora existam espécies que ocorrem exclusivamente em matas de galeria e utilizem corpos d'água lóticos para se reproduzir.

A fototerapia com diodo emissor de luz (LEDT) aplicada pré-exercício inibe a peroxidação lipídica em atletas após exercício de alta intensidade: um estudo preliminar

Estresse oxidativo é o termo geralmente utilizado para descrever os danos causados pelo desequilíbrio entre pró-oxidantes e antioxidantes no organismo. O aumento no consumo de O2 induzido pelo exercício físico está associado ao aumento das espécies reativas de oxigênio (EROs) sendo estas indutoras do estresse oxidativo. Embora as evidências indiquem um provável efeito inibitório da fototerapia com diodos emissores de luz (LEDT) sobre a produção das EROs, não existem estudos observando tal efeito em atletas. Este estudo preliminar destina-se a verificar os efeitos da aplicação de LEDT previamente ao exercício de alta intensidade sobre a peroxidação lipídica, mensurada através dos níveis sanguíneos de substâncias reativas ao ácido tiobarbitúrico (TBARS). Todos os seis atletas de voleibol do sexo masculino foram submetidos às duas situações: aplicação de LEDT efetiva e aplicação de LEDT placebo. O desempenho no protocolo de exercício adotado não revelou diferença (p > 0,05) entre as duas situações nas variáveis potência pico, potência média e índice de fadiga. Os resultados relacionados com a peroxidação lipídica foram: na situação LEDT efetiva, não foi possível observar diferença estatisticamente significante (p > 0,05) entre os níveis pré e pós-exercício (6,98 ± 0,81 e 7,02 ± 0,47nmol/mL); na situação LEDT (LBP) placebo, houve diferença estatisticamente significante (p = 0,05) entre os valores pré e pós-exercício (7,09 ± 1,28 e 8,43 ± 0,71nmol/mL). Tais resultados demonstram que a aplicação efetiva de LEDT parece ser eficaz no controle da peroxidação lipídica em atletas submetidos a exercício intenso

Distribuição de tensões em mini-implantes ortodônticos

O objetivo deste trabalho foi avaliar a distribuição de tensões na resina em contato com os filetes de roscas de mini-implantes cilíndricos e cônicos, submetidos à carga lateral e torção de inserção. Um modelo fotoelástico foi confeccionado com gelatina transparente, para simular o osso alveolar. O modelo foi observado com um polariscópio plano e fotografado antes e após a ativação dos mini-implantes com força lateral e de inserção. A aplicação de cargas laterais provocou momentos fletores nos mini-implantes, aparecimento de franjas isocromáticas ao longo dos filetes do corpo dos mini-implantes e no ápice. Quando foi aplicado o torque de inserção, verificou-se a concentração de tensões próxima ao ápice. Concluiu-se que: (1) o mini-implante cilíndrico apresentou maior concentração de tensões no ápice, e (2) o mini-implante cônico apresentou maior concentração de tensões nos filetes de rosca apicais.

A novel polar-based human face recognition computational model

Motivated by a recently proposed biologically inspired face recognition approach, we investigated the relation between human behavior and a computational model based on Fourier-Bessel (FB) spatial patterns. We measured human recognition performance of FB filtered face images using an 8-alternative forced-choice method. Test stimuli were generated by converting the images from the spatial to the FB domain, filtering the resulting coefficients with a band-pass filter, and finally taking the inverse FB transformation of the filtered coefficients. The performance of the computational models was tested using a simulation of the psychophysical experiment. In the FB model, face images were first filtered by simulated V1- type neurons and later analyzed globally for their content of FB components. In general, there was a higher human contrast sensitivity to radially than to angularly filtered images, but both functions peaked at the 11.3-16 frequency interval. The FB-based model presented similar behavior with regard to peak position and relative sensitivity, but had a wider frequency band width and a narrower response range. The response pattern of two alternative models, based on local FB analysis and on raw luminance, strongly diverged from the human behavior patterns. These results suggest that human performance can be constrained by the type of information conveyed by polar patterns, and consequently that humans might use FB-like spatial patterns in face processing.

The use of a graphite-silicone rubber composite electrode in the determination of rutin in pharmaceutical formulation

The possibility of using a graphite silicone-rubber composite electrode (GSR) in a differential pulse voltammetric(DPV) procedure for rutin (vitamin P) determination is described. Cyclic voltammograms of rutin presented a reversible pair of oxidation/reduction peaks respectively at 0.411 and 0.390 V (vs. SCE) at the GSR surface in Britton-Robinson(B-R) buffer solution pH 4.0. In DPV after optimization of conditions, an oxidation peak at 0.370 V (vs. SCE) was used to quantitative determination of rutin in B-R buffer solution pH 4.0. In this case a linear dynamic range of 5.0×10-8 to 50.0×10-8 mol L-1 was observed with a detection limit of 1.8×10-8 mol L-1 for the analyte. Recoveries from 94 to 113% were observed. The electrode surface was renewed by polishing after each determination, with a repeatability of 1.09 ± 0.06 µA (n = 10) peak current. Rutin was determined in a pharmaceutical formulation using the proposed electrode and the results agreed with those from an official method within 95% confidence level.

Screening process for activity determination of conductive oxide electrodes for organic oxidation

A modified method for the calculation of the normalized faradaic charge (q fN) is proposed. The method involves the simulation of an oxidation process, by cyclic voltammetry, by employing potentials in the oxygen evolution reaction region. The method is applicable to organic species whose oxidation is not manifested by a defined oxidation peak at conductive oxide electrodes. The variation of q fN for electrodes of nominal composition Ti/RuX Sn1-X O2 (x = 0.3, 0.2 and 0.1), Ti/Ir0.3Ti0.7O2 and Ti/Ru0.3Ti0.7O2 in the presence of various concentrations of formaldehyde was analyzed. It was observed that electrodes containing SnO2 are the most active for formaldehyde oxidation. Subsequently, in order to test the validity of the proposed model, galvanostatic electrolyses (40 mA cm-2) of two different formaldehyde concentrations (0.10 and 0.01 mol dm-3) were performed. The results are in agreement with the proposed model and indicate that this new method can be used to determine the relative activity of conductive oxide electrodes. In agreement with previous studies, it can be concluded that not only the nature of the electrode material, but also the organic species in solution and its concentration are important factors to be considered in the oxidation of organic compounds.

Evaluation of a simple hyphenated system for flow injection solid-phase pre-concentration and capillary electrophoresis

In this work, the development and evaluation of a hyphenated flow injection-capillary electrophoresis system with on-line pre-concentration is described. Preliminary tests were performed to investigate the influence of flow rates over the analytical signals. Results revealed losses in terms of sensitivity of the FIA-CE system when compared to the conventional CE system. To overcome signal decrease and to make the system more efficient, a lower flow rate was set and an anionic resin column was added to the flow manifold in order to pre-concentrate the analyte. The pre-concentration FIA-CE system presented a sensitivity improvement of about 660% and there was only a small increase of 8% in total peak dispersion. These results have confirmed the great potential of the proposed system for many analytical tasks especially for low concentration samples.

Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

The circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearly-synoptic hourly hydrographic, current (ADCP velocity and volume transport) and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms-1) were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms-1) and the peak flood currents were 0.75 and 0.60 ms-1, respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified) and Type 1a (well mixed). Volume transports were very close, ranging from -3,500 to 3,100 m³s-1 at the ebb and flood, respectively, with a residual -630 m³s-1. The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg.L-1 at the estuary mouth, to 10 mg.L-1 at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle.

Nyssomyia intermedia (Lutz & Neiva) and Nyssomyia neivai (Pinto) (Diptera, Psychodidae, Phlebotominae) in a sympatric area: seasonal and nocturnal hourly rhythm in black and white modified Shannon traps

Captures with black and white Shannon traps were undertaken to identify aspects of the behavior of the two cryptic and sympatric species implicated as vectors of cutaneous leishmaniasis, Nyssomyia intermedia (Lutz & Neiva, 1912) and Nyssomyia neivai (Pinto, 1926). The traps were installed side by side, monthly, from July 2001 to June 2002, from 18 to 07 hours, in a peridomicile of Iporanga municipality, state of São Paulo, Brazil. A total of 2,142 specimens were captured, Ny. intermedia (47.4%) and Ny. neivai (50.5%). The white trap was more attractive to both sexes of both species. Males of Ny. neivai predominated (70%) over those of Ny. intermedia on the two traps; on the black trap, the females of Ny. intermedia predominated (63.3%) over those of Ny. neivai (36.7%). Seventy percent of the specimens of both species were captured between 18 and 24 h. Females of Ny. intermedia presented the highest peak at 19-20 h, and those of Ny. neivai at 20-21 h. The highest hourly average for females of Ny. intermedia on the black trap occurred in the winter and that for males in the summer. For Ny. neivai, both sexes predominated in the summer. The two species probably transmit the cutaneous leishmaniasis in the area due to their great predominance.

Poluição da queima de cana e sintomas respiratórios em escolares de Monte Aprazível, SP

OBJETIVO: Estimar a prevalência de sintomas respiratórios e analisar fatores associados, bem como medidas de pico de fluxo expiratório em escolares. MÉTODOS: Estudo descritivo transversal com escolares de dez a 14 anos de Monte Aprazível, SP. Foram aplicados questionários sobre sintomas de asma e de rinite do protocolo International Study of Asthma and Allergies in Childhood, questões sociodemográficas, fatores predisponentes e antecedentes pessoais e familiares. Foram realizadas medidas repetidas do pico de fluxo expiratório nas crianças e dos níveis de concentração de material particulado (MP2,5) e de black carbon. RESULTADOS: A prevalência de sintomas de asma foi de 11% e de 33,2% de rinite; 10,6% apresentaram mais de quatro crises de sibilos nos últimos 12 meses. Antecedentes familiares para bronquite e rinite associaram-se à presença de asma (p = 0,002 e p < 0,001) e de rinite atuais (p < 0,001 e p < 0,001, respectivamente). Para rinite, houve associação com presença de mofo ou rachadura na casa (p = 0,009). Houve maior freqüência de rinite nos meses de junho a outubro, período de safra da cana de açúcar. Prevalência diária de pico de fluxo expiratório abaixo de 20% da mediana de medidas na criança foi maior em dias com maior concentração de MP2,5. CONCLUSÕES: A prevalência de sintomas de asma está abaixo e a de rinite está acima da média nacional. Ainda que dentro dos níveis aceitáveis, a poluição nos períodos de queima da palha da cana-de-açúcar pode contribuir para a exacerbação de episódios de asma e de rinite.