Multi-axis MEMS force sensor for measuring friction components involved in dexterous micromanipulation: Design and optimization.

International audienceAt the nanoscale and for particular applications such as dexterous micro-manipulation, two Degrees of Freedom nanotribometers are no longer adequate for studying and characterizing the contacts. This paper deals with the specifications and working principle of a new multi-axis friction sensor designed for nanotribological testing applied to this purpose in order to extract each contribution independently (ie, sliding, rolling and spin motion). It is composed ofa central platform with a fixed ball and surrounded by a compliant table. Its sensing ability is based on piezoresistivity: four sets of piezoresistors are symmetrically distributed at the root of four central beams. Finite Elements Method simulations are performed to find the optimal dimensions of the sensor. As results, this sensor could measure independently normal and friction forces in the range of 1 mN and 100 μN, respectively and the three rotation components. Estimated crosstalk is lower than 1 % with a good sensitivity

An approach for data mining of electronic health record data for suicide risk management: Database analysis for clinical decision support

Background: In an electronic health context, combining traditional structured clinical assessment methods and routine electronic health-based data capture may be a reliable method to build a dynamic clinical decision-support system (CDSS) for suicide prevention. Objective: The aim of this study was to describe the data mining module of a Web-based CDSS and to identify suicide repetition risk in a sample of suicide attempters. Methods: We analyzed a database of 2802 suicide attempters. Clustering methods were used to identify groups of similar patients, and regression trees were applied to estimate the number of suicide attempts among these patients. Results: We identified 3 groups of patients using clustering methods. In addition, relevant risk factors explaining the number of suicide attempts were highlighted by regression trees. Conclusions: Data mining techniques can help to identify different groups of patients at risk of suicide reattempt. The findings of this study can be combined with Web-based and smartphone-based data to improve dynamic decision making for clinicians.This study received a Hospital Clinical Research Grant (PHRC 2009) from the French Health Ministry. None of the funding sources had any involvement in the study design; collection, analysis, or interpretation of data; writing of the report; or the decision to submit the paper for publication. This study was funded partially by Instituto de Salud Carlos III (ISCIII PI13/02200; PI16/01852), Delegación del Gobierno para el Plan Nacional de Drogas (20151073), and the American Foundation for Suicide Prevention (LSRG-1-005-16)

Attenuation of Soft-Tissue Sarcomas Resistance to the Cytotoxic Action of TNF-α by Restoring p53 Function

BACKGROUND: Isolated limb perfusion with TNF-α and melphalan is used with remarkable efficiency to treat unresectable limb sarcomas. Here we tested the ability of TNF-α to directly induce apoptosis of sarcoma cells. In addition, we investigated the impact of p53 in the regulation of such effect. METHODOLOGY/PRINCIPAL FINDINGS: We first analysed the ability of TNF-α to induce apoptosis in freshly isolated tumour cells. For this purpose, sarcoma tumours (n = 8) treated ex vivo with TNF-α were processed for TUNEL staining. It revealed substantial endothelial cell apoptosis and levels of tumour cell apoptosis that varied from low to high. In order to investigate the role of p53 in TNF-α-induced cell death, human sarcoma cell lines (n = 9) with different TP53 and MDM2 status were studied for their sensitivity to TNF-α. TP53(Wt) cell lines were sensitive to TNF-α unless MDM2 was over-expressed. However, TP53(Mut) and TP53(Null) cell lines were resistant. TP53 suppression in TP53(Wt) cell lines abrogated TNF-α sensitivity and TP53 overexpression in TP53(Null) cell lines restored it. The use of small molecules that restore p53 activity, such as CP-31398 or Nutlin-3a, in association with TNF-α, potentiated the cell death of respectively TP53(Mut) and TP53(Wt)/MDM2(Ampl). In particular, CP-31398 was able to induce p53 as well as some of its apoptotic target genes in TP53(Mut) cells. In TP53(Wt)/MDM2(Ampl) cells, Nutlin-3a effects were associated with a decrease of TNF-α-induced NF-κB-DNA binding and correlated with a differential regulation of pro- and anti-apoptotic genes such as TP53BP2, GADD45, TGF-β1 and FAIM. CONCLUSION/SIGNIFICANCE: More effective therapeutic approaches are critically needed for the treatment of unresectable limb sarcomas. Our results show that restoring p53 activity in sarcoma cells correlated with increased sensitivity to TNF-α, suggesting that this strategy may be an important determinant of TNF-α-based sarcomas treatment

Quantitative MRI to Characterize the Nucleus Pulposus Morphological and Biomechanical Variation According to Sagittal Bending Load and Radial Fissure, an ex vivo Ovine Specimen Proof-of-Concept Study

Background and context: Low back pain is a dramatic burden worldwide. Discography studies have shown that 39% of chronic low back pain patients suffer from discogenic pain due to a radial fissure of intervertebral disc. This can have major implications in clinical therapeutic choices. The use of discography is restricted because of its invasiveness and interest in it remains low as it represents a static condition of the disc morphology. Magnetic Resonance Imaging (MRI) appears to be less invasive but does not describe the biomechanical dynamic behavior of the fissure.Purpose: We aimed to seek a quantitative MRI protocol combined with ex vivo sagittal loading to analyze the morphological and biomechanical changes of the intervertebral disc structure and stress distribution.Study design: Proof of concept.Methods: We designed a proof-of-concept ovine study including 3 different 3.0 T-MRI sequences (T2-weighted, T1 and T2 mapping). We analyzed 3 different mechanical states (neutral, flexion and extension) on a fresh ovine spine specimen to characterize an intervertebral disc before and after puncturing the anterior part of the annulus fibrosus. We used a mark tracking method to calculate the bending angles and the axial displacements of the discal structures. In parallel, we created a finite element model to calculate the variation of the axial stress and the maximal intensity shear stress, extrapolated from our experimental boundary conditions.Results: Thanks to an original combination of specific nuclear relaxation time quantifications (T1, T2) of the discal tissue, we characterized the nucleus movement/deformation into the fissure according to the synchronous mechanical load. This revealed a link between disc abnormality and spine segment range of motion capability. Our finite element model highlighted significant variations within the stress distribution between intact and damaged disc.Conclusion: Quantitative MRI appears to provide a new opportunity to characterize intra-discal structural morphology, lesions and stress changes under the influence of mechanical load. This preliminary work could have substantial implications for non-invasive disc exploration and could help to validate novel therapies for disc treatment

Introduction to Big Data and Its Applications in Insurance

International audienceWe present an introduction to big data and its application in insurance (impact of big data, 5V and others, tools and architecture for big data, example of application in insurance)

Méthodes de data mining et applications à l'analyse de bases de données de suicidants

International audienceLes grandes étapes d'un processus de data mining ainsi que quelques méthodes d'apprentissage supervisées et non supervisées seront présentées et illustrées sur un exemple pédagogique. Enfin, les premiers résultats d'un processus complet de data mining sur une base de données de suicidants montreront l'intérêt du data mining pour déterminer des groupes de suicidants et pour identifier des facteurs de risque associés au nombre de tentatives de suicide