Repair bond strength of a resin composite to alumina-reinforced feldspathic ceramic

This study compared the microtensile bond strength of a repair resin to an alumina-reinforced feldspathic ceramic (Vitadur-alpha, Vita) after 3 surface conditioning methods: Group 1, etching with 9.6% hydrofluoric acid for 1 minute plus rinsing and drying, followed by application of silane for 5 minutes; group 2, airborne particle abrasion with 110-mm aluminum oxide using a chairside air-abrasion device followed by silane application for 5 minutes; group 3, chairside tribochemical silica coating with 30-mu m SiOx followed by silane application for 5 minutes (N = 30). Group 1 presented the highest mean bond strength (19.7 +/- 3.8 MPa), which was significantly higher than those of groups 2 (10 +/- 2.6 MPa) and 3 (10.4 +/- 4 MPa) (P <.01). Scanning electron microscope analysis of the failure modes demonstrated predominantly mixed types of failures, with adhesive and/or cohesive failures in all experimental groups.

Complete staining of nerve fiber and myoneural junctions with acetylthiocholine and silver

We describe a combined stain for simultaneous demonstration of the preterminal axons and cholinesterase activity at myoneural junctions of mammalian muscles. This technique employs acetylthiocholine iodide as the substrate for cholinesterase activity and silver nitrate impregnation of preterminal axons. The procedure is rapid, simple and uses fresh muscles. Intramuscular nerves, preterminal axons and myoneural junctions are stained simultaneously brown or black with minimal background staining of connective tissue and muscle fibers.

Resin-based composite reinforced sealant

Purpose: To describe and picture a technique for using a resin-bonded sealant reinforced by inclusion of resin-based composite, before polymerization. Method: Using an extracted mandibular molar, embedded in plaster and isolated with a rubber dam, a step-by-step depiction of the technique is shown. Results: A picture of a six-year-old sealant in a first permanent molar, still in perfect condition, is shown. Conclusion: This technique offers a reliable method for treating pits and fissures.

An ultra stable glass system for optical fiber devices

In this paper a modified chalcogenide glass was studied by X-ray powder diffraction, differential thermal analysis, infrared and Raman scattering spectroscopies. The study of this new matrix opens new perspectives to fabricate Pr3+-doped fibers to operate as an optical amplifier in the 1.3 mum telecommunications window. The Pr3+-doped 70Ga(2)S(3)-30La(2)S(3) glass was modified through the substitution of La2S3 by La2O3, which improves the thermal stability of these glasses without any modification of phonon energy. The possibility to pull a fiber from this glass system without any devitrification is easily achieved.

Non-linear boundary element analysis of floor slabs reinforced with rectangular beams

In this work, a numerical model to perform non-linear analysis of building floor structures is proposed. The presented model is derived from the Kirchhoff-s plate bending formulation of the boundary element method (BENI) for zoned domains, in which the plate stiffness is modified by the presence of membrane effects. In this model, no approximation of the generalized forces along the interface is required and the compatibility and equilibrium conditions along interfaces are imposed at the integral equation level. In order to reduce the number of degrees of freedom, the Navier Bernoulli hypothesis is assumed to simplify the strain field for the thin sub-regions (rectangular beams). The non-linear formulation is obtained from the linear formulation by incorporating initial internal force fields, which are approximated by using the well-known cell sub-division. Then, the non-linear solution of algebraic equations is obtained by using the concept of the consistent tangent operator. The Von Mises criterion is adopted to govern the elasto-plastic material behaviour checked at points along the plate thickness and along the rectangular beam element axes. The numerical representations are accurately obtained by either computing analytically the element integrals or performing the numerical integration accurately using an appropriate sub-elementation scheme. (C) 2007 Elsevier Ltd. All rights reserved.

Food and dietary fiber intake by children with or without constipation. Assessment according to the food guide pyramid and the American Health Foundation (AHF)

We studied the ingestion of 54 children with functional constipation (CC) and 41 without (Control), according to the Food Pyramid. A food frequency questionnaire was used, analyzing fruits with or without peel/bagasse, grains whole or refined, and beans separately. Total subjects and 2-6y CC ingested less DF (g/day) than Control (p < 0.05). The majority had high n degrees of dairy and of the meat group servings, but most groups/subgroups did not meet recommendation for fruit and vegetable. A greater proportion of fruit with peel/bagasse in Control than in CC was almost the only difference for 6-12y. There was a discrepancy between the high percentage of children with DF above AHF recommendation and the high percentage of children who did not meet Pyramid recommendations.

Influence of Environmental Conditioning on the Shear Behavior of Poly(phenylene sulfide)/Glass Fiber Composites

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hygrothermal Aging Effect on Fatigue Behavior of GLARE

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