872 resultados para Ceramic tools


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Canine parasitic zoonoses pose a continuing public health problem, especially in developing countries and communities that are socioeconomically disadvantaged. Our study combined the use of conventional and molecular epidemic, logical tools to determine the role of dogs in transmission of gastrointestinal (GI) parasites such as hookworms, Giardia and Ascaris in a parasite endemic teagrowing community in northeast India. A highly sensitive and specific molecular tool was developed to detect and differentiate the zoonotic species of canine hookworm eggs directly from faeces. This allowed epidemiological screening of canine hookworm species in this community to be conducted with ease and accuracy. The zoonotic potential of canine Giardia was also investigated by characterising Giardia duodenalis recovered from humans and dogs living in the same locality and households at three different loci. Phylogenetic and epidemiological analysis provided compelling evidence to support the zoonotic transmission of canine Giardia. Molecular tools were also used to identify the species of Ascaris egg present in over 30% of dog faecal samples. The results demonstrated the role of dogs as a significant disseminator and environmental contaminator of Ascaris lumbricoides in communities where promiscuous defecation practices exist. Our study demonstrated the usefulness of combining conventional and molecular parasitological and epidemiological tools to help solve unresolved relationships with regards to parasitic zoonoses.

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Allergy is a major cause of morbidity worldwide. The number of characterized allergens and related information is increasing rapidly creating demands for advanced information storage, retrieval and analysis. Bioinformatics provides useful tools for analysing allergens and these are complementary to traditional laboratory techniques for the study of allergens. Specific applications include structural analysis of allergens, identification of B- and T-cell epitopes, assessment of allergenicity and cross-reactivity, and genome analysis. In this paper, the most important bioinformatic tools and methods with relevance to the study of allergy have been reviewed.

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This study investigated the organic and inorganic constituents of healthy leaves and Candidatus Liberibacter asiaticus (CLas)-inoculated leaves of citrus plants. The bacteria CLas are one of the causal agents of citrus greening (or Huanglongbing) and its effect on citrus leaves was investigated using laser-induced breakdown spectroscopy (LIBS) combined with chemometrics. The information obtained from the LIBS spectra profiles with chemometrics analysis was promising for the construction of predictive models to identify healthy and infected plants. The major, macro- and microconstituents were relevant for differentiation of the sample conditions. The models were then applied to different inoculation times (from 1 to 8 months). The models were effective in the classification of 82-97% of the diseased samples with a 95% significance level. The novelty of this method was in the fingerprinting of healthy and diseased plants based on their organic and inorganic contents. (C) 2010 Elsevier B.V. All rights reserved.

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This study aimed to investigate bone responses to a novel bioactive fully crystallized glass-ceramic of the quaternary system P(2)O(5)-Na(2)O-CaO-SiO(2) (Biosilicates (R)). Although a previous study demonstrated positive effects of Biosilicate (R) on in vitro bone-like matrix formation, its in vivo effect was not studied yet. Male Wistar rats (n = 40) with tibial defects were used. Four experimental groups were designed to compare this novel biomaterial with a gold standard bioactive material (Bioglass (R) 45S5), unfilled defects and intact controls. A three-point bending test was performed 20 days after the surgical procedure, as well as the histomorphometric analysis in two regions of interest: cortical bone and medullary canal where the particulate biomaterial was implanted. The biomechanical test revealed a significant increase in the maximum load at failure and stiffness in the Biosilicate group (R) (vs. control defects), whose values were similar to uninjured bones. There were no differences in the cortical bone parameters in groups with bone defects, but a great deal of woven bone was present surrounding Biosilicate (R) and Bioglass (R) 45S5 particulate. Although both bioactive materials supported significant higher bone formation; Biosilicate (R) was superior to Bioglass (R) 45S5 in some histomorphometric parameters (bone volume and number of osteoblasts). Regarding bone resorption, Biosilicate (R) group showed significant higher number of osteoclasts per unit of tissue area than defect and intact controls, despite of the non-significant difference in the osteoclastic surface as percentage of bone surface. This study reveals that the fully crystallized Biosilicate (R) has good bone-forming and bone-bonding properties. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 978: 139-147, 2011.

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Titanium carbonitride-based cermets are important materials for contemporary cutting tools. Ceramic powders of Ti(CN), TaC, WC were mixed, compacted and heat-treated at high temperatures to form (Ti, W, Ta)(C, N) solid solution, which was then ball-milled to fine powders before being mixed with metallic binder and compacted. Liquid-phase sintering of the samples was carried out in a nitrogen atmosphere at different sintering temperatures and holding times. The microhardness and porosity of the sintered cermets were studied. It is demonstrated that the microhardness increases with sintering temperature, but at the same time, the porosity level also goes up with temperature and time. At the beginning of sintering (zero holding time), the majority of the pores are small (0.1 similar to 1 mu m); during sintering, the larger ports grow at the expense of smaller pores and the resulting pores are all concentrated in the 10 similar to 100 mu m range. The number of larger pores increases with temperature and prolonged holding time, which results in deteriorated properties. (C) 1997 Elsevier Science S.A.

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Objective: International nutritional screening tools are recommended for screening hospitalized patients for nutritional risk, but no tool has been specifically evaluated in the Brazilian population. The aim of this study was to identify the most appropriate nutritional screening tool for predicting unfavorable clinical outcomes in patients admitted to a Brazilian public university hospital. Methods: The Nutritional Risk Screening 2002 (NRS 2002), Mini-Nutritional Assessment-Short Form (MNA-SF), and Malnutrition Universal Screening Tool (MUST) were administered to 705 patients within 48 h of hospital admission. Tool performance in predicting complications, very long length of hospital stay (LOS), and death was analyzed using receiver operating characteristic curves. Results: NRS 2002, MUST, and MNA-SF identified nutritional risk in 27.9%, 39.6%, and 73.2% of the patients, respectively. NRS 2002 (complications: 0.6531; very long LOS: 0.6508; death: 0.7948) and MNA-SF(complications: 0.6495; very long LOS: 0.6197; death: 0.7583) had largest areas under the ROC curve compared to MUST (complications: 0.6036; very long LOS: 0.6109; death: 0.6363). For elderly patients, NRS 2002 was not significantly different than MNA-SF (P>0.05) for predicting outcomes. Conclusion: Considering current criteria for nutritional risk, NRS 2002 and MNA-SF have similar performance to predict outcomes but NRS 2002 seems to provide a best yield. (C) 2010 Elsevier Inc. All rights reserved.

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Study Design: Data mining of single nucleotide polymorphisms (SNPs) in gene pathways related to spinal cord injury (SCI). Objectives: To identify gene polymorphisms putatively implicated with neuronal damage evolution pathways, potentially useful to SCI study. Setting: Departments of Psychiatry and Orthopedics, Faculdade de Medicina, Universidade de Sao Paulo, Brazil. Methods: Genes involved with processes related to SCI, such as apoptosis, inflammatory response, axonogenesis, peripheral nervous system development and axon ensheathment, were determined by evaluating the `Biological Process` annotation of Gene Ontology (GO). Each gene of these pathways was mapped using MapViewer, and gene coordinates were used to identify their polymorphisms in the SNP database. As a proof of concept, the frequency of subset of SNPs, located in four genes (ALOX12, APOE, BDNF and NINJ1) was evaluated in the DNA of a group of 28 SCI patients and 38 individuals with no SC lesions. Results: We could identify a total of 95 276 SNPs in a set of 588 genes associated with the selected GO terms, including 3912 nucleotide alterations located in coding regions of genes. The five non-synonymous SNPs genotyped in our small group of patients, showed a significant frequency, reinforcing their potential use for the investigation of SCI evolution. Conclusion: Despite the importance of SNPs in many aspects of gene expression and protein activity, these gene alterations have not been explored in SCI research. Here we describe a set of potentially useful SNPs, some of which could underlie the genetic mechanisms involved in the post trauma spinal cord damage.

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Purpose: To evaluate the effect of the opaque layer firing temperature and mechanical and thermal cycling on the flexural strength of a ceramic fused to commercial cobalt-chromium alloy (Co-Cr). The hypotheses were that higher opaque layer temperatures increase the metal/ceramic bond strength and that aging reduces the bond strength. Materials and Methods: Metallic frameworks (25 x 3 x 0.5 mm(3); ISO 9693) (N = 60) were cast in Co-Cr and airborne-particle abraded (Al(2)O(3): 150 mu m) at the central area of the frameworks (8 x 3 mm(2)) and divided into three groups (N = 20), according to the opaque layer firing temperature: Gr1 (control)-900 degrees C; Gr2-950 degrees C; Gr3-1000 degrees C. The opaque ceramic (Opaque, Vita Zahnfabrick, Bad Sackingen, Germany) was applied, and the glass ceramic (Vita Omega 900, Vita Zahnfabrick) was fired onto it (thickness: 1 mm). While half the specimens from each group were randomly tested without aging (water storage: 37 degrees C/24 hours), the other half were mechanically loaded (20,000 cycles; 50 N load; distilled water at 37 degrees C) and thermocycled (3000 cycles; 5 degrees C to 55 degrees C, dwell time: 30 seconds). After the flexural strength test, failure types were noted. The data were analyzed using 2-way ANOVA and Tukey`s test (alpha = 0.05). Results: Gr2 (19.41 +/- 5.5 N) and Gr3 (20.6 +/- 5 N) presented higher values than Gr1 (13.3 +/- 1.6 N) (p = 0.001). Mechanical and thermal cycling did not significantly influence the mean flexural strength values (p > 0.05). Increasing the opaque layer firing temperature improved the flexural bond strength values (p < 0.05). The hypotheses were partially accepted. Conclusion: Increasing of the opaque layer firing temperature improved the flexural bond strength between ceramic fused to Co-Cr alloy.

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In a changing employment climate and with the growth of demand for careers guidance at all stages of life, careers guidance practice has moved from its positivist world view, with the counsellor as expert and client as passive responder, to more holistic 'constructivist' approaches. In essence, these approaches view the career as a holistic concept in which work and personal life are inextricably intertwined, and individuals are experts in their own lives, actively constructing their careers. The first to fully explore the constructivist approach, this book: provides a theoretical background to constructivism; outlines a range of constructivist approaches to career counselling; and gives examples of the practical application of constructivism. Essential for anyone involved in career guidance wishing to learn more about this vital new approach, this book combines theory with practicable guidance, and represents a new direction for career counselling.