On the feasibility of defect detection in composite material based on thermal periodic excitation

Implementation of periodic thermal excitation to identify thermal properties (conductivity, heat capacity, diffusivity) of complex composite materials at different investigation scales (from micrometer to millimetre) presents many advantages. These methods are usually based on the thermal waves phase lag observation compared to a reference signal. In fact, phase lag evolution versus distance to the heating source or versus excitation frequency is quite informative about numerous material characteristics. For example, considering that a structural defect can modify heat propagation inside a material, diagnosis can be performed from phase lag observations and comparisons between samples with and without defects. Numerous studies have been performed considering global heating (a quite large surface of the investigated composite material is heated and defect depth or size can be detected). The proposed approach is original since periodic heating is local and aims to detect defects in the periphery of the excitation. Based on a mathematical model for thermal waves propagations and introducing complex temperature for numerical resolution (finite element method), a feasibility study has allowed a sensitivity analysis. This preliminary study also provides information on the operating protocol, for heating (frequency, power, size of the source), and observation (transmission or reflection). Then, experimental device and early experimental results are briefly exposed

O6-Methylguanine-DNA methyltransferase protein expression by immunohistochemistry in brain and non-brain systemic tumours: systematic review and meta-analysis of correlation with methylation-specific polymerase chain reaction

Background: The DNA repair protein O6-Methylguanine-DNA methyltransferase (MGMT) confers resistance to alkylating agents. Several methods have been applied to its analysis, with methylation-specific polymerase chain reaction (MSP) the most commonly used for promoter methylation study, while immunohistochemistry (IHC) has become the most frequently used for the detection of MGMT protein expression. Agreement on the best and most reliable technique for evaluating MGMT status remains unsettled. The aim of this study was to perform a systematic review and meta-analysis of the correlation between IHC and MSP. Methods A computer-aided search of MEDLINE (1950-October 2009), EBSCO (1966-October 2009) and EMBASE (1974-October 2009) was performed for relevant publications. Studies meeting inclusion criteria were those comparing MGMT protein expression by IHC with MGMT promoter methylation by MSP in the same cohort of patients. Methodological quality was assessed by using the QUADAS and STARD instruments. Previously published guidelines were followed for meta-analysis performance. Results Of 254 studies identified as eligible for full-text review, 52 (20.5%) met the inclusion criteria. The review showed that results of MGMT protein expression by IHC are not in close agreement with those obtained with MSP. Moreover, type of tumour (primary brain tumour vs others) was an independent covariate of accuracy estimates in the meta-regression analysis beyond the cut-off value. Conclusions Protein expression assessed by IHC alone fails to reflect the promoter methylation status of MGMT. Thus, in attempts at clinical diagnosis the two methods seem to select different groups of patients and should not be used interchangeably

Détection de défaut à l'aide d'une sollicitation thermique périodique - Etude de faisabilité

La mise en oeuvre de sollicitations thermiques périodiques pour l\u27identification de propriétés thermiques (conductivité, chaleur volumique, diffusivité) de matériaux complexes à différentes échelles d\u27investigation (micrométrique, millimétrique) présente de nombreux avantages. Ces méthodes reposent en général sur l\u27observation du déphasage de l\u27onde thermique par rapport au signal de référence. L\u27évolution de ce déphasage en fonction de la distance à la source ou en fonction de la fréquence d\u27excitation renseigne sur le paramètre inconnu. En ce qui concerne la recherche d\u27un défaut, que l\u27on pourrait caractériser ici comme étant la cause d\u27une modification significative du comportement \u27de référence\u27 du matériau, les approches basées sur l\u27analyse du déphasage et du module de l\u27onde thermique résultante d\u27une chauffe périodique restent rares. Mettant en oeuvre le modèle mathématique satisfait par la température complexe, une étude de faisabilité numérique a été réalisée. Basée sur une analyse de sensibilité, celle ci a permis de mettre en évidence l\u27influence de la profondeur du défaut, de sa nature, de sa distance à la source chauffante. Cette étude préliminaire fournit aussi des informations sur le protocole opératoire pour la chauffe (fréquence, puissance, taille de la source) et pour l\u27observation (en transmission ou en réflexion). Enfin, de premiers résultats expérimentaux sont montrés

Association of sensing techniques with a designed ICT architecture in the ISTIMES project: application example with the monitoring of the Musmeci Bridge

This work gives a brief description of the main activities and outcomes of the Integrated System for Transport Infrastructures surveillance and Monitoring by Electromagnetic Sensing (ISTIMES) project, which aimed at designing and implementing a system able to couple the capabilities of long-term monitoring and quick damage assessment of the critical transport infrastructures. This was performed thanks to the integrated use of the novel and state of art concepts of Earth observation, ground-based sensing techniques and ICT architecture. The paper will give a brief outline of the main results of the project by referring in particular to the demonstration activities at the test bed of the “Musmeci” Bridge in Potenza, Southern Italy

Reliability and Validity of the Dutch Version of the International Physical Activity Questionnaire in Patients After Total Hip Arthroplasty or Total Knee Arthroplasty

<p>STUDY DESIGN: Psychometric assessment.</p><p>OBJECTIVES: To determine test-retest reliability and concurrent validity of the International Physical Activity Questionnaire (IPAQ) in patients after total hip arthroplasty or total knee arthroplasty.</p><p>BACKGROUND: Despite recognized benefits of regular physical activity, little is known about the physical activity level of patients after total hip arthroplasty or total knee arthroplasty. None of the currently used questionnaires is internationally accepted. The IPAQ tries to address this problem, but its validity and reliability in those who have had a total hip arthroplasty or total knee arthroplasty are unknown.</p><p>METHODS: Forty-four patients completed the IPAQ (short and long forms) twice. Test-retest reliability was assessed by Spearman correlation coefficients (r) and intraclass correlation coefficients. Additionally, standard error of measurement and minimal detectable change were calculated. Concurrent validity was determined by an accelerometer. Spearman correlation coefficients were calculated between IPAQ scores and accelerometer data. Bland-Altman analyses were performed for both reliability and validity.</p><p>RESULTS: Fair to good correlation coefficients were found for test-retest reliability of the total and activity scores (r = 0.49-0.81, intraclass correlation coefficient = 0.27-0.71). Standard error of measurement and minimal detectable change were large. For concurrent validity, weak to moderate correlation coefficients were found for total and activity scores (r = -0.07 to 0.54). Systematic bias was found between the IPAQ and accelerometer data, with higher scores on the IPAQ.</p><p>CONCLUSION: Overall, the IPAQ showed fair reliability and weak concurrent validity. These results are in line with previous studies of the reliability and validity of the IPAQ. Due to systematic bias and large standard error of measurement and minimal detectable change, the IPAQ may only be suitable for intergroup comparisons.</p>

MGMT promoter methylation in malignant gliomas: ready for personalized medicine?

The DNA repair enzyme O(6)-methylguanine-DNA methyltransferase (MGMT) antagonizes the genotoxic effects of alkylating agents. MGMT promoter methylation is the key mechanism of MGMT gene silencing and predicts a favorable outcome in patients with glioblastoma who are exposed to alkylating agent chemotherapy. This biomarker is on the verge of entering clinical decision-making and is currently used to stratify or even select glioblastoma patients for clinical trials. In other subtypes of glioma, such as anaplastic gliomas, the relevance of MGMT promoter methylation might extend beyond the prediction of chemosensitivity, and could reflect a distinct molecular profile. Here, we review the most commonly used assays for evaluation of MGMT status, outline the prerequisites for standardized tests, and evaluate reasons for difficulties in reproducibility. We critically discuss the prognostic and predictive value of MGMT silencing, reviewing trials in which patients with different types of glioma were treated with various chemotherapy schedules, either up-front or at recurrence. Standardization of MGMT testing requires comparison of different technologies across laboratories and prospectively validated cut-off values for prognostic or predictive effects. Moreover, future clinical trials will need to determine, for each subtype of glioma, the degree to which MGMT promoter methylation is predictive or prognostic, and whether testing should become routine clinical practice

Physical activity at home, at leisure, during transportation and at work in French adults with type 2 diabetes: The ENTRED physical activity study

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