964 resultados para Dental stress analysis


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Hsp70 proteins are a family of molecular chaperones that are involved in many aspects of protein homeostasis. In this study, an Hsp70 homologue (SoHsp70) was identified from red drum Sciaenops ocellatus and analyzed at molecular level. The open reading frame of SoHsp70 is 1920 bp and intronless, with a 5'-untranslated region (UTR) of 399 bp and a 3'-UTR of 241 bp. The deduced amino acid sequence of SoHsp70 shares 84-92% overall identities with the Hsp70s of a number of fish species. In silico analysis identified in SoHsp70 three conserved Hsp70 domains involved in nucleotide and substrate binding. The coding sequence of SoHsp70 was subcloned into Escherichia coli, from which recombinant SoHsp70 was purified and, upon ATPase assay, found to exhibit apparent ATPase activity. Expressional analysis showed that constitutive expression of SoHsp70 was detectable in heart, liver, spleen, kidney, brain, blood, and gill. Experimental challenges with poly(I:C) and bacterial pathogens of Gram-positive and Gram-negative nature induced SoHsp70 expression in kidney to different levels. Stress-responsive analysis of SoHsp70 expression in primary cultures of red drum hepatocytes showed that acute heat shock treatment elicited a rapid induction of SoHsp70 expression which appeared after 10 min and 30 min of treatment. Exposure of hepatocytes separately to iron, copper, mercury, and hydrogen peroxide significantly unregulated SoHsp70 expression in time-dependent manners. Vaccination of red drum with a Streptococcus iniae bacterin was also found to induce SoHsp70 expression. Furthermore, recombinant SoHsp70 enhanced the immunoprotective effect of a subunit vaccine. Taken together, these results suggest that SoHsp70 is a stress-inducible protein that is likely to play a role in immunity and in coping with environmental and biological stresses. (C) 2010 Elsevier Ltd. All rights reserved.

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Ferritins are conserved Iron storage proteins that exist in most living organisms and play an essential role in Iron homeostasis. In this study, we reported the identification and analysis a ferritin M subunit, SmFerM, from turbot Scophthalmus maximus. The full length cDNA of SmFerM contains a 5'-untranslated region (UTR) of 232 bp, an open reading frame (ORF) of 531 bp, and a 3'-UTR of 196 bp The ORF encodes a putative protein of 176 amino acids, which shares extensive sequence identities with the M terrains of several fish species. In silico analysis identified in SmFerM both the ferroxidase center of mammalian H ferritins and the iron nucleation site of mammalian L ferritins. Quantitative real time reverse transcriptase-PCR analysis indicated that SmFerM expression was highest in muscle and lowest in heart and responded positively to experimental challenges with bacterial pathogens and poly(I center dot C) Exposure of cultured turbot hepatocytes to treatment of stress inducers (iron, copper, and H2O2) significantly upregulated the expression of SmFerM in a dose dependent manner. Iron chelating analysis showed that recombinant SmFerM purified from Escherichia coli exhibited apparent iron binding activity. These results suggest that SmFerM is a functional M ferritin and is likely to play a role in iron sequestration and protection against oxidative stress and microbial infection (C) 2010 Elsevier Inc All rights reserved

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Aim. This paper is a report of a study to test the proposed factor structure of the Index of Sources of Stress in Nursing Students. Background. Research across many countries has identified a number of sources of distress in nursing students but little attempt has been made to understand and measure sources of eustress or those stressors likely to enhance performance and well-being. The Index of Sources of Stress in Nursing Students was developed to do this. Exploratory factor analysis suggested a three-factor structure, the factors being labelled: learning and teaching; placement-related and course organization. It is important, however, to subject the instrument to confirmatory factor analysis as a further test of construct validity. Method. A convenience sample of final year nursing students (n = 176) was surveyed in one university in Northern Ireland in 2007. The Index of Sources of Stress in Nursing Students, which measures sources of stress likely to contribute to distress and eustress, was completed electronically. The LISREL programme was used to carry out the confirmatory factor analysis and test the factor structure suggested in the exploratory analysis. Findings. The proposed factor structure for the items measuring ‘Uplifts’ proved to be a good fit to the data and the proposed factor structure for the items measuring ‘Hassles’ showed adequate fit. Conclusion. In nursing programmes adopting the academic model and combining university-based learning with placement experience, this instrument can be used to help identify the sources of stress or course demands that students rate as distressing and those that help them to achieve. The validity of the ISSN could be further evaluated in other education settings.

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Objectives This study focused on estimating the relative risk of coronary heart disease (CHD) in association with work stress, as indicated by the job-strain model, the effort-reward imbalance model, and the organizational injustice model.

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In this article, we take advantage of the recent availability of data from the special module on material deprivation in the 2009 European Union Statistics on Income and Living Conditions to develop a more comprehensive understanding of the relationship between material deprivation and economic stress, the mediating and moderating roles played by cross-national differences in levels of income and income inequality, and the implications for competing perspectives on the nature of reference groups in Europe. The article establishes the critical role of basic deprivation, relating to inability to enjoy customary standards of living, in influencing economic stress levels. National income levels and inequality had no direct influence on economic stress. However, the impact of basic deprivation was stronger in countries with higher levels of income, indicating the crucial role of national reference groups. An interaction between basic deprivation and income inequality was also observed. However, contrary to the expectation that experiencing basic deprivation in a national context of high income inequality is likely to be particularly stressful, the consequences of such deprivation were most negative in low inequality countries. Experiencing basic deprivation where high income levels and lower inequality would lead to the expectation that such deprivation is eminently avoidable exacerbates its impact. © The Author 2013.

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To investigate whether work related stress, measured and defined as job strain, is associated with the overall risk of cancer and the risk of colorectal, lung, breast, or prostate cancers.

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Objective: The aim of this research is to use finite element analysis (FEA) to quantify the effect of the sample shape and the imperfections induced during the manufacturing process of samples on the bond strength and modes of failure of dental adhesive systems through microtensile test. Using the FEA prediction for individual parameters effect, estimation of expected variation and spread of the microtensile bond strength results for different sample geometries is made. Methods: The estimated stress distributions for three different sample shapes, hourglass, stick and dumbbell predicted by FEA are used to predict the strength for different fracture modes. Parameters such as the adhesive thickness, uneven interface of the adhesive and composite and dentin, misalignment of axis of loading, the existence of flaws such as induced cracks during shaping the samples or bubbles created during application of the adhesive are considered. Microtensile experiments are performed simultaneously to measure bond strength and modes of failure. These are compared with the FEA results. Results: The relative bonding strength and its standard deviation for the specimens with different geometries measured through the microtensile tests confirm the findings of the FEA. The hourglass shape samples show lower tensile bond strength and standard deviation compared to the stick and dumbbell shape samples. ANOVA analysis confirms no significant difference between dumbbell and stick geometry results, and major differences of these two geometries compared to hourglass shape measured values. Induced flaws in the adhesive and misalignment of the angle of application of load have significant effect on the microtensile bond strength. Using adhesive with higher modulus the differences between the bond strength of the three sample geometries increase. Significance: The result of the research clarifies the importance of the sample geometry chosen in measuring the bond strength. It quantifies the effect of the imperfections on the bond strength for each of the sample geometries through a systematic and all embracing study. The results explain the reasons of the large spread of the microtensile test results reported by various researchers working in different labs and the need for standardization of the test method and sample shape used in evaluation of the dentin-adhesive bonding system. © 2007 Academy of Dental Materials.

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Since 2008, Ireland has experienced the most severe economic and labour market crisis since the foundation of the State. These economic and labour market changes have had a stark impact on the standard of living across the Irish population. The rapid deterioration in the labour market, the rising level of household indebtedness and stringent austerity measures to plug the public finance deficit have had a widespread impact yet there is debate about where the heaviest burden has fallen and where the economic stress has been felt most. The paper analyses data from the Survey of Income and Living Conditions for the period 2004 to 2011. The aim of the paper is to develop and test a measure of economic stress, which will capture some of the aspects of the rapid change in economic fortunes on Irish households that are not picked up by income alone. This includes tapping into features of the recession such as debt problems, unsustainable housing costs, and other difficulties associated with managing on reduced household income in a period of uncertainty. In testing such a measure we examine trends over time from boom to bust in the Irish economy and consider how economic stress is distributed across different socio-economic groups. The paper explores the distribution and level of economic stress across income class groups, social classes and the life-course and tests the thesis of ‘middle class squeeze’.

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Three groups of cows representing three ranges of welfare in the production system were included in the study: two groups of Bruna dels Pirineus beef cattle maintained under different management systems (good and semiferal conditions) and a group of Alberes cows, a breed that lives in the mountains (hardest conditions).

In order to identify new stress/welfare biomarkers, serum from Bruna cows living in both environments was subjected to DIGE labelling, two-dimensional electrophoresis and MALDI-MS or ion trap MS. Identification was achieved for 15 proteins, which mainly belonged to three biological functions, the oxidative stress pathway (glutathione peroxidase (GPx) and paraoxonase (PON-1)), the acute phase protein family (Heremans Schmid glycoprotein alpha2 (α2-HSG)) and the complement system.

Biological validation included the Alberes breed. GPx and PON-1 were validated by an enzymatic assay and found to be higher and lower, respectively, in cows living in hard conditions. α2-HSG was validated by ELISA and found to be reduced in hard conditions. Other biomarkers of the redox status were also altered by living conditions: protein carbonyl content, superoxide dismutase (SOD) and glutathione reductase (GR).

Our results show that changes in the redox system are the main adaptation of cows living in challenging environmental conditions. This article is part of a Special Issue entitled: “Farm animal proteomics”.

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AIM: To describe the patterns of dental attendance and attitudes towards tooth loss of general dental practice patients in Galway.

OBJECTIVES: 1. To determine the pattern of adult dental attendance in general practices in Galway; and, 2. To examine the oral health attitudes of these patients.

METHOD: Questionnaires were distributed to 311 consecutive adult patients in the waiting rooms of ten general dental practices in Galway, which were randomly selected from the telephone directory.

RESULTS: A total of 254 of the 311 questionnaires distributed were fully completed, returned and included in the results, giving a response rate of 81.7%. A total of 59% of dentate participants attended their dentist for annual or biannual examinations compared to 23% of edentate patients. Some 10.5% of medical card holders and 0.5% of non-medical card holders were edentulous.

CONCLUSIONS: The data from the survey indicated that medical card holders in Galway were more likely to be edentulous than nonmedical card holders. Edentate patients were less likely to be regular dental attenders than dentate patients.