Search results for "Aggregate"
showing 10 items of 287 documents
The cytotoxic evaluation of mineral trioxide aggregate and bioaggregate in the subcutaneous connective tissue of rats
2013
Objectives: The purpose of this study was to evaluate and compare the cytotoxic effects of ProRoot MTA and DiaRoot BA, a bioceramic nanoparticulate cement, on subcutaneous rat tissue. Study D esign: Fifty Sprouge Dawley rats were used in this study. Polyethylene tubes filled with ProRoot MTA and DiaRoot BioAggregate, along with a control group of empty, were implanted into dorsal connective tissue of rats for 7, 15, 30, 60, and 90 days. After estimated time intervals the rats were sacrificed. The specimens were fixed, stained with hematoxylin and eosin, and then evaluated under a light microscope for inflammatory reactions and mineralization. Results: All groups evoked a severe to moderate …
Comparison of two histopathologic methods for evaluating subcutaneous reaction to mineral trioxide aggregate
2011
Objectives: One of the most important factors for suitable materials for pulp therapy is biocompatibility. Two histopathologic methods of Cox and Federation Dentaire International (FDI) were used to evaluate inflammation. In Cox method, density of inflammatory cells, tissue reactions like fibrosis, vascular responses like congestion and fibrin extravasation have been used to evaluate inflammatory reactions. The aim of this study was to compare the accuracy of pathologists’ interpretations using two different methods. Study design: Three pathologists observed the degree of inflammation in 225 histopathologic sections. These sections showed inflammation in subcutaneous connective tissue of ra…
Repair of bone defect by nano-modified white mineral trioxide aggregates in rabbit: a histopathological study
2014
Background: Many researchers have tried to enhance materials functions in different aspects of science using nano-modification method, and in many cases the results have been encouraging. To evaluate the histopathological responses of the micro-/nano-size cement-type biomaterials derived from calcium silicate-based composition with addition of nano tricalcium aluminate (3CaO.Al 2 O 3 ) on bone healing response. Material and Methods: Ninety mature male rabbits were anesthetized and a bone defect was created in the right mandible. The rabbits were divided into three groups, which were in turn subdivided into five subgroups with six animals each based on the defect filled by: white mineral tri…
169th ENMC International Workshop Rare Structural Congenital Myopathies 6–8 November 2009, Naarden, The Netherlands
2011
This international ENMC workshop assembled 18 clinicians and scientists from Europe, the United States of America, South America, Japan and Australia to discuss “Rare Structural Congenital Myopathies (CM)”. This workshop can be considered a follow-up to an earlier one [1], then and now excluding classical CM on which separate workshops have repeatedly been held at ENMC and respective consortia exist such as on nemaline myopathies, centronuclear myopathies, core myopathies, as well as protein aggregate myopathies. CM can be classified according to CM-specific morphological features, certain epidemiological aspects or on molecular grounds. This workshop addressed those rare CM which, to date,…
Nanoaggregates Based on New Poly-Hydroxyethyl-Aspartamide Copolymers for Oral Insulin Absorption
2013
The aim of this work was to produce copolymers with an appropriate hydrophilic/hydrophobic balance able to form nanoaggregates with protein molecules and to be used as ideal materials in the field of oral peptide/protein delivery. New anionic polymers obtained by the conjugation of carboxy-bearing ligands, like succinic anhydride and/or cysteine, to hydrophobized α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) copolymers have been synthesized and characterized. Starting copolymer was synthesized by the partial derivatization of hydroxyl groups on the PHEA backbone with butylamine (C4) (obtaining the PHEA-C4 copolymer, bearing a butyl moiety). The consecutive reaction of PHEA-C4 with succin…
Contractual Satisfaction: The Polish and Tanzanian Perspectives
2013
Purpose: Interfirm satisfaction has been studied at the aggregate level, which has limited use in terms of understanding specific dimensions. Contractual satisfaction relates to the specific level of analyzing interfirm satisfaction. This study contributes towards understanding contractual satisfaction and the contextual nature of the concept. To achieve the latter, two heterogeneous emerging markets were used (Poland and Tanzania). Methodology: The study was conducted in Poland and Tanzania, focusing on manufacturing firms. The sample included 201 Polish firms and 240 Tanzanian firms. Findings: The major findings suggest that ex ante costs and ex post specifications have a significant posi…
Matching inefficiencies, regional disparities and unemployment
2009
. In this paper we apply a stochastic frontier approach to examine how matching inefficiencies and regional disparities in structural factors contribute to regional and aggregate unemployment. Our results suggest that there would be a substantial decline in aggregate unemployment if (i) all local labour offices operated with full efficiency or (ii) they shared the same structure of job seekers and vacant jobs as the most favourable office. In the former case an increase in hirings would lower the average unemployment rate by 2.4 percentage points. In the latter case the decrease would be 1.4 percentage points. Further, we find that fixed effects are positively correlated with both a more f…
Creep of polymer concrete in the nonlinear region
2000
Two polyester-based polymer concretes with various volume content of diabase as an extender and aggregate are tested in creep under compression at different stress levels. The phenomenological and structural approaches are both used to analyze the experimental data. Common features of changes in the instantaneous and creep compliances are clarified, and a phenomenological creep model which accounts for the changes in the instantaneous compliance and in the retardation spectrum depending on the stress level is developed. It is shown that the model can be used to describe the experimental results of stress relaxation and creep under repeated loading. Modeling of the composite structure and su…
Mechanical properties of steel fibre reinforced lightweight concrete with pumice stone or expanded clay aggregates
2001
This paper presents basic information on the mechanical properties of steel fibre-reinforced light-weight concrete, manufactured using pumice stone or expanded clay aggregates. Results are presented for standard compressive tests and indirect tensile tests (splitting tests on cylinder specimens and flexure tests on prismatic beams using a three-point loading arrangement) under monotonically increasing or cyclically varying loads. The influence of steel fibres and aggregate types on modulus of elasticity, compressive and tensile strength and post-peak behaviour is evaluated. Test results show that compressive strength does not change for pumice stone aggregates, while an increase is observed…
Pumice concrete for structural wall panels
2003
Some properties of lightweight pumice stone concrete (LWPSC) are discussed, on account of a possible structural use of this material. Then the results of an experimental investigation are described, in order to show that pumice can really be considered an alternative to common artificial lightweight aggregates, taking into account the performance pointed out by loading tests carried out on structural systems made of LWPSC. Three different kinds of reinforced wall panels were made using LWPSC, lightweight expanded clay concrete and normal weight concrete; then their structural responses under horizontal cyclic and constant vertical forces were compared, above all with reference to lateral st…