Foot Modeling and Smart Plantar Pressure Reconstruction from Three Sensors

International audienceIn order to monitor pressure under feet, this study presents a biomechanical model of the human foot. The main elements of the foot that induce the plantar pressure distribution are described. Then the link between the forces applied at the ankle and the distribution of the plantar pressure is established. Assumptions are made by defining the concepts of a 3D internal foot shape, which can be extracted from the plantar pressure measurements, and a uniform elastic medium, which describes the soft tissues behaviour. In a second part, we show that just 3 discrete pressure sensors per foot are enough to generate real time plantar pressure cartographies in the standing position or during walking. Finally, the generated cartographies are compared with pressure cartographies issued from the F-SCAN system. The results show 0.01 daN (2% of full scale) average error, in the standing position

Visible And Near Infrared Spectroscopy For PSE-Like Zones Classification At Different Post Mortem Times

International audience– The ability of visible and near infrared spectroscopy (VIS-NIRS) to predict PSE-like zone classification was examined on 150 deboned hams at 5 post mortem times (12, 16, 20, 24 and 36 h pm). Four probes were used to investigate the accuracy. Two of our probes were prototypes. Partial Least Squares Discriminant Analysis (PLSDA) was used to determine the prediction models from spectrums recorded on semimembranosus muscle. Surface probes gave better results than inserted probes. The best probe showed moreover a good accuracy whatever the pm times was when measuring (78 to 86 % good prediction in external validation as the 24 h pm model was used). Its false negative/false positive ratios were favorable at the early pm times (12 to 20 h pm). So an early PSE-like zones prediction is possible using VIS-NIRS. The prototype probe inserted showed good results (82,9% good prediction in external validation) and would deserve additional validation on bone-in hams, as industrials need. Key Words – VIS-NIR spectroscopy, prototype probes, pork meat, PSE-like zones, PLSDA

Mesure de la perception de la qualité audiovisuelle par analyse conjointe de signaux physiologiques

National audienceL'influence de la qualité audiovisuelle (AV) sur l'utilisateur a été étudiée à partir de l'analyse de mesures physiologiques complétant les mesures subjectives habituellement utilisées. Le présent papier propose une méthode d'analyse de ces signaux basée sur l'extraction d'indicateurs et la définition d'un modèle empirique de détection automatique (par fusion de données hétérogènes) des modifications éventuelles de l'activité physiologique en réaction à la présence de dégradations de qualité et plus globalement, à la présentation de stimuli AV. Abstract - The influence of the video quality (AV) assessment was studied upon the basis of physiological measurements in addition to subjectives measurements usually used. In this paper, we propose new indicators extracted from these signals and an empirical method (with heterogenous data fusion) for automatic detection of physiological reaction due to quality degradation or more generally in response of stimuli

Pulse Rate Analysis in Case of Central Sleep Apnea: A New Algorithm for Cardiac Rate Estimation

Annual International Conference of the IEEEInternational audienceThis paper first describes the AM-FM demodulation of an arterial pressure signal. Although it is known to be efficient on signals modulated by breathing, we demonstrate that in case of lack of respiratory modulation (central sleep apnea), the AM-FM algorithm doesn't perform well in heart rate extraction. We introduce then a new algorithm based on Singular Spectrum Analysis eigen values which performs better cardiac frequency estimation in this context. The error for cardiac frequency estimation is around 0.2 BPM (Beats Per Minute) versus 5.5 BPM for the AM-FM demodulation. Further experimentations will be performed (with this time both cardiac and respiratory assessments) and will deal with real sleep apnea cases

Comparison Of Two Methods For Demodulation Of Pulse Signals - Application In Case Of Central Sleep Apnea

In the field of 24/7 human health monitoring, pervasive computing makes possible the continuous analysis of physiological parameters from an ambulatory device with a great acceptability. This paper presents two methods for obtaining cardiac and respiratory rates from a single arterial pressure signal: AM-FM demodulation and Singular Spectrum Analysis (SSA). With the aim to monitor sleep apnea, two simulated central sleep apnea were performed and recorded with Biopac reference system. The results showed a good evaluation of the cardiac rate with Singular Spectrum Analysis and bad results with AM-FM demodulation. For the respiration rate, some other signals were tested with average results for both methods. Further experiments will deal with real sleep apnea cases and algorithm improvements

Microscopie de fluorescence résolue à 1µm, rapide et faible coût Application à la sécurité alimentaire

http://www.univ-st-etienne.fr/opt-diag/National audienceProposal of low cost, submicrometer, and fast fluorescence microscopy Microarray scanners are now reaching submicron details for fast scan speeds on large surfaces such as microscope slides. Reading times depend on the required resolution. However, specific applications in food security tend to bring closer to the source the measurements necessary to decision making. For the development of salmonella and listeria on pig carcasses, the measurements taken directly at slaughter need to be interpreted within less than an hour, so that the decision of meat usage in a fresh/cooking circuit does not have significant economic consequence. We developed a method for marking immediately after impacting carcass, which makes it possible to read fluorescence signals 30 minutes after sampling. However, the sampling method leaves the sample some organic residues, whose irregularities in the thickness and the surface can cause problems in reading and interpretation with conventional scanners. We propose a method of packaging and reading for the automatic counting of salmonella with fast scanning, adapted to the environment of the slaughterhouse. Detection is carried out by a 488nm excitation and a conventional 520 nm fluorescence detection using a photomultiplier. The assembly proposed uses optical fibers. It provides a resolution close to 0.5 µm, the diffraction limit at 488nm

Évaluation du stress : application à la détection des chutes

National audienceThis paper deals with the association of several physiological parameters in order to estimate a stress level that can be use in the detection of falls or the evaluation of fear of falling among elderly people

Prédiction du rendement technologique des jambons par spectroscopie optique : mise en place et validation en contexte industriel

Session 7 - Green & Biophotonique (C7.2)International audiencePrédiction du rendement technologique des jambons par spectroscopie optique : mise en place et validation en contexte industriel Le rendement de fabrication des jambons est un enjeu pour l'industrie agro-alimentaire : une valeur faible de ce rendement dit technologique se traduit par une dépréciation de valeur et de qualité des jambons [1]. Le tri des carcasses pour la réalisation des jambons cuits supérieurs s'appuie sur une mesure de pH mais n'est pas optimal en terme de résultats, c'est pour cette raison que l'on essaie de lui substituer une mesure par spectromètrie. Dans ce but, un projet a été mis en place mettant en oeuvre une chaîne de mesure complète. Il suppose le design de plusieurs sondes de surface et de pénétration (afin d'explorer un site de mesure optimisé en profondeur et orientation), la mise en oeuvre d'un spectromètre (gamme visible et proche infra-rouge cf. Figure 1), puis du traitement de spectre par une méthode d'apprentissage automatique (Partial Least Square PLS cf. [2]), et l'affichage des résultats et de leur communication au sein du réseau informatique de l'industriel abatteur. Figure 1: Matériel utilisé : sonde de pénétration, spectromètre ASD Labspec, sonde de surface (connectique SMA) 2. Aspects historiques et objectifs L'utilisation, dans le cadre d'un projet de recherche, d'un spectromètre requière en général une phase de collecte des données, suivi d'une phase d'analyse (calibration du modèle) de ces données afin de bâtir un modèle de prédiction à l'aide de descripteurs objectifs fournis par ailleurs. Le spectromètre est un appareil connecté à un PC et comprenant un logiciel spécifique en charge de réaliser les opérations d'acquisition des spectres. Les spectres collectés sont en général transférés sur un autre ordinateur afin d'y être traités par un logiciel dédié à l'analyse statistique, une exportation des données dans un format exploitable par ce logiciel est souvent nécessaire. En routine, l'exploitation du modèle statistique issue de la calibration permet pour chaque spectre le calcul d'un ou plusieurs paramètres pertinents utilisable en tant que critère de sélection et de tri des jambons analysés

Prediction Of Beef Fatty Acid Composition Using Near Infrared Spectroscopy: Effects Of Tissue And Sample Preparations

International audienceThe aims of the study were to determine the best site of bovine carcass for predicting fatty acid (FA) composition using a NIRS (near infrared spectroscopy) portable equipment and to study the effect of different methods of sample preparation. 78 animals were sampled from different types and rearing systems. Seven tissues (Longissimus thoracis, Infraspinatus, Diaphragma, Rectus abdominis, shoulder subcutaneous adipose tissue (SAT), intercostal SAT and intermuscular fat at the 5th rib) were measured after sampling and grinding in liquid nitrogen. The effect of samples preparation were measured on carcass (C0), muscle without grinding (B0), ground with a meat chopper (B1), ground with a knife mill (B2) on RA muscle. FA composition was assessed using gas chromatograph and the spectra were measured at wavelengths between 350 and 2500 nm. For adipose tissue, FA were not correctly predicted from NIRS. However, predictions were more satisfactory for the major FA (C16:0, C18:0, C18:1d9c), total saturated and monounsaturated FA of muscles. The results show a better prediction of FA composition concomitant with an increased gradient of sample homogenization. For other FA and especially polyunsaturated fatty acids, the performances were not satisfactory for quantitative purposes whatever the grinding method

Clinical spectrum of MTOR-related hypomelanosis of Ito with neurodevelopmental abnormalities.

PURPOSE: Hypomelanosis of Ito (HI) is a skin marker of somatic mosaicism. Mosaic MTOR pathogenic variants have been reported in HI with brain overgrowth. We sought to delineate further the pigmentary skin phenotype and clinical spectrum of neurodevelopmental manifestations of MTOR-related HI. METHODS: From two cohorts totaling 71 patients with pigmentary mosaicism, we identified 14 patients with Blaschko-linear and one with flag-like pigmentation abnormalities, psychomotor impairment or seizures, and a postzygotic MTOR variant in skin. Patient records, including brain magnetic resonance image (MRI) were reviewed. Immunostaining (n = 3) for melanocyte markers and ultrastructural studies (n = 2) were performed on skin biopsies. RESULTS: MTOR variants were present in skin, but absent from blood in half of cases. In a patient (p.[Glu2419Lys] variant), phosphorylation of p70S6K was constitutively increased. In hypopigmented skin of two patients, we found a decrease in stage 4 melanosomes in melanocytes and keratinocytes. Most patients (80%) had macrocephaly or (hemi)megalencephaly on MRI. CONCLUSION: MTOR-related HI is a recognizable neurocutaneous phenotype of patterned dyspigmentation, epilepsy, intellectual deficiency, and brain overgrowth, and a distinct subtype of hypomelanosis related to somatic mosaicism. Hypopigmentation may be due to a defect in melanogenesis, through mTORC1 activation, similar to hypochromic patches in tuberous sclerosis complex