The critical barrier to progress in dentine bonding with the etch-and-rinse technique

Objectives: The lack of durability in resin-dentine bonds led to the use of chlorhexidine as MMP-inhibitor to prevent the degradation of hybrid layers. Biomimetic remineralisation is a concept-proven approach in preventing the degradation of resin-dentine bonds. The purpose of this study is to examine the integrity of aged resin-dentine interfaces created with a nanofiller-containing etch-and-rinse adhesive after the application of these two approaches.Methods: The more established MMP-inhibition approach was examined using a parallel in vivo and in vitro ageing design to facilitate comparison with the biomimetic remineralisation approach using an in vitro ageing design. Specimens bonded without chlorhexidine exhibited extensive degradation of the hybrid layer after 12 months of in vivo ageing.Results: Dissolution of nanofillers could be seen within a water-rich zone within the adhesive layer. Although specimens bonded with chlorhexidine exhibited intact hybrid layers, water-rich regions remained in those hybrid layers and degradation of nanofillers occurred within the adhesive layer. Specimens subjected to in vitro biomimetic remineralisation followed by in vitro ageing demonstrated intrafibrillar collagen remineralisation within hybrid layers and deposition of mineral nanocrystals in nanovoids within the adhesive.Conclusions: The impact was realized by understanding the lack of an inherent mechanism to remove water from resin-dentine interfaces as the critical barrier to progress in bonding with the etch-and-rinse technique. The experimental biomimetic remineralisation strategy offers a creative solution for incorporating a progressive hydration mechanism to achieve this goal, which warrants its translation into a clinically applicable technique. (C) 2011 Elsevier Ltd. All rights reserved.

Generalization of the Hamilton-Jacobi approach for higher-order singular systems

We generalize the Hamilton-Jacobi formulation for higher-order singular systems and obtain the equations of motion as total differential equations. To do this we first study the constraints structure present in such systems.

Hamilton-Jacobi approach to Berezinian singular systems

In this work we present a formal generalization of the Hamilton-Jacobi formalism, recently developed For singular systems, to include the case of Lagrangians containing variables which are elements of Berezin algebra. We derive the Hamilton-Jacobi equation for such systems, analyzing the singular case in order to obtain the equations of motion as total differential equations and study the integrability conditions for such equations. An example is solved using both Hamilton-Jacobi and Dirac's Hamiltonian formalisms and the results are compared. (C) 1998 Academic Press.

Natural radionuclides in major aquifer systems of the Parana sedimentary basin, Brazil

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

Impact of different grazing systems for bovine cattle on the soil microbiological and chemical characteristics

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

Evaluation of economic impact of external eauivalent models used in reactive OPF studies for interconnected systems

Reactive-optimisation procedures are responsible for the minimisation of online power losses in interconnected systems. These procedures are performed separately at each control centre and involve external network representations. If total losses can be minimised by the implementation of calculated local control actions, the entire system benefits economically, but such control actions generally result in a certain degree of inaccuracy, owing to errors in the modelling of the external system. Since these errors are inevitable, they must at least be maintained within tolerable limits by external-modelling approaches. Care must be taken to avoid unrealistic loss minimisation, as the local-control actions adopted can lead the system to points of operation which will be less economical for the interconnected system as a whole. The evaluation of the economic impact of the external modelling during reactive-optimisation procedures in interconnected systems, in terms of both the amount of losses and constraint violations, becomes important in this context. In the paper, an analytical approach is proposed for such an evaluation. Case studies using data from the Brazilian South-Southeast system (810 buses) have been carried out to compare two different external-modelling approaches, both derived from the equivalent-optimal-power-flow (EOPF) model. Results obtained show that, depending on the external-model representation adopted, the loss representation can be flawed. Results also suggest some modelling features that should be adopted in the EOPF model to enhance the economy of the overall system.

Carbon dioxide emissions after application of tillage systems for a dark red latosol in southern Brazil

Soil tillage may influence CO2 emissions in agricultural systems. Agricultural soils are managed in several ways in Brazil, ranging from no tillage to intensive land preparation. The objective of this study was to determine the effect of common soil tillage treatments (disk harrow, reversible disk plow, rotary tiller and chisel plow tillage systems) on the intermediate CO2 emissions of a dark red latosol, located in southern Brazil. Different tillage systems produced significant differences in the CO2 emissions, and the results indicate that the chisel plow produced the highest soil carbon loss during the 15 days period after tillage treatments were performed. Emissions to the atmosphere increased as much as 74 g CO2 m(-2), at the end of a 2-week period, in the plot where the chisel plow treatment was applied, in comparison to the non-disturbed plot. The results indicate that the total increase on the intermediate term soil CO2 emissions due to tillage treatments in southern Brazil is comparable to that reported for the more humid and cooler regions. (C) 2001 Elsevier B.V. B.V All rights reserved.

Influence of age on the behavior of dental pulp of dog teeth after capping with an adhesive system or calcium hydroxide

This study evaluated histomorphologically the influence of chronological age of the dog on the dental pulp-healing process after capping with the All Bond 2 system or with calcium hydroxide paste. The animals were divided according to age into young and adult groups. Class 5-type cavities were prepared, and the pulp was submitted to an exposure of a diameter of 0.5 mm. The pulp of the teeth was then protected with the adhesive system or with a calcium hydroxide paste. Sixty days after treatment, the results obtained with the adhesive system in the young group were significantly better than those in the adult group. With calcium hydroxide, the results were similar for both groups. The pulp treated with calcium hydroxide exhibited a complete hard tissue bridge and a pulp without inflammatory reaction, a fact not observed when the adhesive system was used. In conclusion, the chronological age of the pulp influenced the comparative results only for the adhesive system (P = 0.1), and the total results were better with calcium hydroxide than with the All Bond 2 system (P = 0.01).

One-year clinical performance of self-etch adhesives in posterior restorations

Purpose: To evaluate the 1-year clinical performance of three self-etching adhesives (Adper Prompt L-Pop, Clearfil S-3 Bond, iBond) in posterior composite restorations using one etch&rinse adhesive (One-Step Plus) as control. Methods: Upon approval by the Institutional Review Board, 121 restorations were inserted in 38 subjects. The adhesives were applied as per manufacturers' instructions. Preparations were restored with a nanofilled resin composite (Filtek Supreme) and evaluated at baseline, 6 months, and 1 year. Statistical analyses included the Chi-square distribution with the McNemar non-parametric test (P< 0.05). Results: At 1 year, 111 restorations in 35 subjects were evaluated using the USPHS modified criteria. No significant changes were observed for the etch&rinse adhesive One-Step Plus. At 1 year the number of Alfa ratings decreased significantly for Clearfil S-3 Bond and for iBond in the categories color match, marginal staining, and marginal adaptation. For Adper Prompt L-Pop, marginal adaptation at 1 year was significantly worse than at baseline. Postoperative sensitivity to air improved significantly for Adper Prompt L-Pop, Clearfil S-3 Bond, and iBond. When the evaluation criteria were paired at 1 year, iBond resulted in a significantly lower number of Alfa ratings than any of the other adhesives for color match, marginal staining, and marginal adaptation. One-Step Plus resulted in a greater number of Alfa ratings for marginal adaptation than either Adper Prompt L-Pop or Clearfil S-3 Bond. Marginal adaptation was significantly better for Clearfil S-3 Bond than for Adper Prompt L-Pop. The post-operative sensitivity measured at 1 year for Adper Prompt L-Pop was statistically better than that for One-Step Plus.

Hamilton-Jacobi formulation for singular systems with second-order Lagrangians

Recently, the Hamilton-Jacobi formulation for first-order constrained systems has been developed. In such formalism the equations of motion are written as total differential equations in many variables. We generalize the Hamilton-Jacobi formulation for singular systems with second-order Lagrangians and apply this new formulation to Podolsky electrodynamics, comparing with the results obtained through Dirac's method.

Optimum design of microirrigation systems in sloping lands

When an area to be irrigated has a high slope gradient in the manifold line direction, an option is to use a tapered pipeline to economize on pipe costs and to keep pressure head variations within desired limits. The objective of this paper is to develop a linear optimization model to design a microirrigation system with tapered, downhill manifold lines, minimizing the equivalent annual cost of the hydraulic network and the annual pumping cost, and maximizing the emission uniformity previously established to the subunit. The input data are irrigation system layout, cost of all hydraulic network components, and electricity price. The output data are equivalent annual cost, pipeline diameter in each line of the system, pressure head in each node, and total operating pressure head. To illustrate its capability, the model is applied in a citrus orchard in Sao, Paulo State, Brazil, considering slopes of 3, 6, and 9%. The model proved to be efficient in the design of the irrigation system in terms of the emission uniformity desired.

EVOLUTION PATTERNS OF THE SOIL ORGANIC-MATTER IN SOME AGRICULTURAL SYSTEMS IN THE BRAZILIAN CERRADO REGION

Several changes in the soil humus characteristics were observed after clearing the Central Brazil virgin forest. When compared with the original ''Cerrado'' forest, the soils from the agricultural systems showed increased values for cation exchange capacity, total organic matter and non-extractable humin. The humic acid fraction underwent some changes suggesting increased oxidation and decreased aliphatic content. The soil organic N tends to accumulate in the insoluble humus fractions.The above changes were much less intense when the virgin forest was transformed into pastures. Under these conditions, the most significant changes were the reduction of readily biodegradable soil organic matter fractions.In view of the intensity of the lixiviation processes in the area studied, the above changes may be connected with the reduction in aggregate stability observed in the cleared sites.In general, the characteristics of the humus formations in the ''Cerrado'' region suggested high resistance to external factors, which is in part attributed to the active insolubilization of humic colloids by the Al and Fe oxides. In the absence of erosive processes in the cleared sites, additional humus stability may conform both to selective biodegradation and/or lixiviation of the humic colloids, or to the effects of the fire used in soil management.

Estimativa da captura total: desenhos amostrais para pesca artesanal

Estimating total landings of artisanal fisheries in managed areas is essential for the development of programs aimed at the establishment of sustainable production systems. However, few experiences addressed the constraints of assessments targeted at multispecific and small scale fisheries with pulverized landings. Total annual production (fish, lobsters and octopus) at the Marine Extractive Reserve of Corumbau, Bahia, Brazil, in 2006, was estimated through yields recorded by fisherfolks, in the scope of a participatory fisheries monitoring program. Three designs were employed: 1) simple random sampling, 2) stratified random sampling by month and fishing frequency, 3) stratified random sampling by community, fishing frequency and months, resulting in estimates of 349t (95% confidence interval = 305-393), 330t (289-372) and 315t (279-351), respectively. This kind of information can help design strategies for aggregation of value to small scale fisheries production, and also for the dimensioning of the corresponding infrastructure. However, these estimates shall not be used to support fishing effort increase, as there is high uncertainty regarding the state of the stocks, as well as limitations related to the asymmetry in monthly landings per fisherfolk and to the sampling coverage in the different strata.

Soil microbial biomass and organic matter fractions during transition from conventional to organic farming systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparison of three systems of classification in predicting the outcome of diabetic foot ulcers in a Brazilian population

Objective: The aim was to compare there ulcer classification systems as predictors of the outcome of diabetic foot ulcers; the Wagner, the University of Texas (UT) and the size (area, depth), sepsis, arteriopathy, denervation system (S(AD)SAD) systems in specialist clinic in Brazil.Methods: Ulcer area, depth, appearance, infection and associated ischaemia and neuropathy were recorded in a consecutive series of 94 subjects. A novel score, the S(AD)SAD score, was derived from the sum of individual items of the S(AD)SAD system, and was evaluated. Follow-up was for at least 6 months. The primary outcome measure was the incidence of healing.Results: Mean age was 57.6 years; 57 (60.6%) were made. Forty-eight ulcers (51.1%) healed without surgery; 11 (12.2%) subjects underwent minor amputation. Significant differences in terms of healing were observed for depth (P = 0.002), infection (P = 0.006) and denervation (P = 0.002) using the S(AD)SAD system, for UT grade (P = 0.002) and stage (P = 0.032) and for Wagner grades (P = 0.002). Ulcers with an S(AD)SAD score of <= 9 (total possible 15) were 7.6 times more likely to heal than scores >= 10 (P < 0.001).Conclusions: All three systems predicted ulcer outcome. The S(AD)SAD score of ulcer severity could represent a useful addition to routine clinical practice. The association between outcome and ulcer depth confirms earlier reports. The association with infection was stronger than that reported from the centres in Europe or North America. The very strong association with neuropathy has only previously been observed in Tanzania. Studies designed to compare the outcome in different countries should adopt systems of classification, which are valid for the populations studied.