Effect of the C-factor and Dentin Preparation Method in the Bond Strength of a Mild Self-etch Adhesive

This study evaluated the effect of the C-factor and dentin preparation method (DPM) in the bond strength (BS) of a mild self-etch adhesive; the study also observed the SEM superficial aspects of the corresponding smear layer. For purposes of this study, 25 molars (n=5) were used in a bond strength test. The molars were divided into two parts (buccal and lingual): one part received a Class V cavity (C-factor=3) and the other received a flat surface (C-factor=0) with the same bur type (coarse diamond or carbide bur and fine diamond or carbide bur), both within the same dentin depth. Five teeth were prepared with wet 60-grit and 600-grit SiC papers. After restoration with Clearfil SE Bond, microtensile beans (0.8 mm(2)) were prepared and tested after 24 hours in a universal testing machine (0.5 mm/minute). An additional two teeth for each DPM were prepared for SEM evaluation of the smear layer superficial aspects. The BS values were submitted to one-way ANOVA, considering only the DPM (flat surfaces) and two-way ANOVA (C-Factor x DPM, considering only burs) with p=0.05. Although the DPM in the flat surfaces was not significant, the standard deviations of carbide bur-prepared specimens were markedly lower. The BS was significantly lower in cavities. The fine carbide bur presented the most favorable smear layer aspect. It was concluded that different dentin preparation methods could not prevent the adverse effect in bond strength of a high C-factor. A coarse cut carbide bur should be avoided prior to a mild self-etch adhesive, because it adversely affected bond strength. In contrast, a fine cut carbide bur provided the best combination: high bond strength with low variability, which suggests a more reliable bond strength performance.

The Drop Technique: a Method to Control the Amount of Fluoride Dentifrice Used by Young Children

Purpose: The purpose of this study was to evaluate the amount of dentifrice applied to the toothbrush by school children using a liquid dentifrice (drop technique), when compared to toothpaste. Materials and Methods: A total of 178 school children (4-8 years old) from two cities in Brazil (Bauru and Bariri) participated in the present two-part crossover study. Children from Bauru received training regarding tooth-brushing techniques and use of dentifrice before data collection. In each phase, the amount of toothpaste or liquid dentifrice applied by the children to the toothbrush was measured, using a portable analytical balance (+/- 0.01 g). Data were tested by analysis of covariance (Ancova) and linear regression (p < 0.05). Results: The mean (+/- standard deviation) amounts of toothpaste and liquid dentifrice applied to the toothbrushes for children from Bauru were 0.41 +/- 0.20 g and 0.15 +/- 0.06 g, respectively. For children from Bariri, the amounts applied were and 0.48 +/- 0.24 g and 0.14 +/- 0.05 g, respectively. The amount of toothpaste applied was significantly larger than the amount of liquid dentifrice for both cities. Children from Bariri applied a significantly larger amount of toothpaste, when compared to those from Bauru. However, for the liquid dentifrice, there was no statistically significant difference between the cities. A significant correlation between the amount of toothpaste applied and the age of the children was verified, but the same was not found for the liquid dentifrice. Conclusion: The use of the drop technique reduced and standardised the amount of dentifrice applied to the toothbrush, which could reduce the risk of dental fluorosis for young children.

The composite Euler method for stiff stochastic differential equations

In this paper we present the composite Euler method for the strong solution of stochastic differential equations driven by d-dimensional Wiener processes. This method is a combination of the semi-implicit Euler method and the implicit Euler method. At each step either the semi-implicit Euler method or the implicit Euler method is used in order to obtain better stability properties. We give criteria for selecting the semi-implicit Euler method or the implicit Euler method. For the linear test equation, the convergence properties of the composite Euler method depend on the criteria for selecting the methods. Numerical results suggest that the convergence properties of the composite Euler method applied to nonlinear SDEs is the same as those applied to linear equations. The stability properties of the composite Euler method are shown to be far superior to those of the Euler methods, and numerical results show that the composite Euler method is a very promising method. (C) 2001 Elsevier Science B.V. All rights reserved.

Improvement of the electrolytic properties of Y2O3-based materials using a crystallographic index

Y2O3 is a c-type rare earth oxide with a fluorite-related structure. This material has been used to refractory because of its high thermal stability and excellent resistance to hydration. In this study, the effective index was suggested in order to improve the electrolytic properties of Y2O3-based oxide. (CexY1-x)(2)O3+delta (x = 0.25 and 0.3) and [LaaSrbCe0.25Y(1-a-b)](2)O3+delta (a = 0.05, 0.1 and 0.15, b = 0, 0.006 and 0.0125) were prepared as the examples with intermediate and high index, respectively. The specimens with high index value such as (La0.15Ce0.25Y0.60)(2)O-3.25 and (La0.1Sr0.0125Ce0.25Y0.6375)(2)O-3.24 consisted of two phases such as c-type and fluorite, although (Ce0.25Y0.75)(2)O-3.25 with intermediate index value had a single phase of c-type rare earth oxide. Microanalysis indicates that a grain in the (La0.1Sr0.0125Ce0.25Y0.6375)(2)O-3.23(7) sintered body consists of c-type and fluorite phases. An interface between c-type and fluorite phases is coherent in a grain. This suggests that this effective index guides the crystal structure in the specimen to fluorite and the examined composition introduces the interface between c-type and fluorite in the microstructure. The electrochemical properties of specimens including Y2O3 were characterized on the basis of the suggested index. The electrical conductivity of Y2O3-based materials increased with an increase of the index. The apparent activation energy of Y2O3-based materials decreased with increasing index. The ionic transport number of oxygen of the specimens was improved by enhancement of the index, confirming validity of the index. The oxide ionic conductive region of (La0.1Sr0.0125Ce0.25Y0.(6375))(2)O-3.23(7) with high effective index extended up to P-O2 = 10(-18) atm at 800 degreesC, although the specimens with low or intermediate index showed p- or n-type semi-conduction in the same P-O2 region at 800 and 1000 degreesC. These results suggest that the interface between c-type and fluorite phases also contributes to improve the electrolytic properties in the grain. It is concluded that the improvement of electrolytic properties in Y2O3-based materials is attributable to the microstructure with interface between two phases in a grain and the fluorite structure guided by the suggested index. (C) 2001 Published by Elsevier Science B.V.

Integrating high and moderate spatial resolution image data to estimate forest age structure

The collection of spatial information to quantify changes to the state and condition of the environment is a fundamental component of conservation or sustainable utilization of tropical and subtropical forests, Age is an important structural attribute of old-growth forests influencing biological diversity in Australia eucalypt forests. Aerial photograph interpretation has traditionally been used for mapping the age and structure of forest stands. However this method is subjective and is not able to accurately capture fine to landscape scale variation necessary for ecological studies. Identification and mapping of fine to landscape scale vegetative structural attributes will allow the compilation of information associated with Montreal Process indicators lb and ld, which seek to determine linkages between age structure and the diversity and abundance of forest fauna populations. This project integrated measurements of structural attributes derived from a canopy-height elevation model with results from a geometrical-optical/spectral mixture analysis model to map forest age structure at a landscape scale. The availability of multiple-scale data allows the transfer of high-resolution attributes to landscape scale monitoring. Multispectral image data were obtained from a DMSV (Digital Multi-Spectral Video) sensor over St Mary's State Forest in Southeast Queensland, Australia. Local scene variance levels for different forest tapes calculated from the DMSV data were used to optimize the tree density and canopy size output in a geometric-optical model applied to a Landsat Thematic Mapper (TU) data set. Airborne laser scanner data obtained over the project area were used to calibrate a digital filter to extract tree heights from a digital elevation model that was derived from scanned colour stereopairs. The modelled estimates of tree height, crown size, and tree density were used to produce a decision-tree classification of forest successional stage at a landscape scale. The results obtained (72% accuracy), were limited in validation, but demonstrate potential for using the multi-scale methodology to provide spatial information for forestry policy objectives (ie., monitoring forest age structure).

Low Intensity Laser Therapy in Temporomandibular Disorder: a Phase II Double-Blind Study

The purpose of this study was to evaluate the analgesic effect of Low Intensity Laser Therapy (LILT) and its influence on masticatory efficiency in patients with temporomandibular dysfunction (TMD). This study was performed using a random, placebo-controlled, and double-blind research design. Fourteen patients were selected and divided into two groups (active and placebo). Infrared laser (780 nm, 70 mw, 60s, 105J/cm(2)) was applied precisely and continuously into five points of the temporomandibular joint (TMJ) area: lateral point (LP), superior point (SP), anterior point (AP), posterior point (PP), and posterior-inferior point (PIP) of the condylar position. This was performed twice per week, for a total of eight sessions, To ensure a double-blind study, two identical probes supplied by the manufacturer were used: one for the active laser and one for the inactive placebo laser. They were marked with different letters (A and B) by a clinician who did not perform the applications. A Visual Analogue Scale (VAS) and a colorimetric capsule method were employed. Data were obtained three times: before treatment (Ev1), shortly after the eighth session (Ev2), and 30 days after the first application (Ev3). Statistical tests revealed significant differences at one percent (1%) likelihood, which implies that superiority of the active group offered considerable TMJ pain improvement. Both groups presented similar masticatory behavior, and no statistical differences were found. With regard to the evaluation session, Ev2 presented the lowest symptoms and highest masticatory efficiency throughout therapy. Therefore, low intensity laser application is effective in reducing TMD symptoms, and has influence over masticatory efficiency [Ev2 (0.2423) and Ev3 (0.2043), observed in the interaction Evaluations x Probes for effective dosage].

Considerations in the design of a mixed-method cluster evaluation of a community programme for 'at-risk' young people

This article discusses the design of a comprehensive evaluation of a community development programme for young people 'at-risk' of self-harming behaviour. It outlines considerations in the design of the evaluation and focuses on the complexities and difficulties associated with the evaluation of a community development programme. The challenge was to fulfil the needs of the funding body for a broad, outcome-focused evaluation while remaining close enough to the programme to accurately represent its activities and potential effects at a community level. Specifically, the strengths and limitations of a mixed-method evaluation plan are discussed with recommendations for future evaluation practice.

A new wavelet-based method for the solution of the population balance equation

A new wavelet-based method for solving population balance equations with simultaneous nucleation, growth and agglomeration is proposed, which uses wavelets to express the functions. The technique is very general, powerful and overcomes the crucial problems of numerical diffusion and stability that often characterize previous techniques in this area. It is also applicable to an arbitrary grid to control resolution and computational efficiency. The proposed technique has been tested for pure agglomeration, simultaneous nucleation and growth, and simultaneous growth and agglomeration. In all cases, the predicted and analytical particle size distributions are in excellent agreement. The presence of moving sharp fronts can be addressed without the prior investigation of the characteristics of the processes. (C) 2001 Published by Elsevier Science Ltd.

Ionic strontium fluorescence as a method for flow tagging velocimetry

A flow tagging technique based upon ionic fluorescence in strontium is investigated for applications to velocity measurements in gas flows. The method is based upon a combination of two laser based spectroscopic techniques, i.e. resonantly-enhanced ionisation and laser-induced ionic fluorescence. Strontium is first ionised and then planar laser-induced fluorescence is utilised to give 2D 'bright images' of the ionised region of the flow at a given time delay. The results show that this method can be used for velocity measurements. The velocities were measured in two types of air-acetylene flames - a slot burner and a circular burner yielding velocities of 5.1 +/- 0.1 m/s and 9.3 +/- 0.2 m/s, respectively. The feasibility of the method for the determination of velocities in faster flows than those investigated here is discussed.

Patient based method of assessing adverse events in clinical trials in rheumatology: the revised Stanford Toxicity Index

We describe the progress towards developing a patient rated toxicity index that meets all of the patient-important attributes defined by the OMERACT Drug Safety Working Party, These attributes are frequency, severity. importance to patient, importance to the clinician, impact on economics, impact on activities, and integration of adverse effects with benefits. The Stanford Toxicity Index (STI) has been revised to collect all attributes with the exception of impact on activities. However, since the STI is a part of the Health Assessment Questionnaire (HAQ). impact on activities is collected by the HAQ. In particular, a new question asks patients to rate overall satisfaction, taking into consideration both benefits and adverse effects. The nest step in the development of this tool is to ensure that the STI meets the OMERACT filter of truth, discrimination, and feasibility. Although truth and feasibility have been confirmed by comparisons within the ARAMIS database, discrimination needs to be assessed in clinical trials.