ParisTech

About: ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Residual stress. The organization has 1888 authors who have published 1965 publications receiving 55532 citations. The organization is also known as: Paris Institute of Technology & ParisTech Développement.

Depth sensitivity analysis of functional near-infrared spectroscopy measurement using three-dimensional Monte Carlo modelling-based magnetic resonance imaging

Abstract: Theoretical analysis of spatial distribution of near-infrared light propagation in head tissues is very important in brain function measurement, since it is impossible to measure the effective optical path length of the detected signal or the effect of optical fibre arrangement on the regions of measurement or its sensitivity. In this study a realistic head model generated from structure data from magnetic resonance imaging (MRI) was introduced into a three-dimensional Monte Carlo code and the sensitivity of functional near-infrared measurement was analysed. The effects of the distance between source and detector, and of the optical properties of the probed tissues, on the sensitivity of the optical measurement to deep layers of the adult head were investigated. The spatial sensitivity profiles of photons in the head, the so-called banana shape, and the partial mean optical path lengths in the skin-scalp and brain tissues were calculated, so that the contribution of different parts of the head to near-infrared spectroscopy signals could be examined. It was shown that the signal detected in brain function measurements was greatly affected by the heterogeneity of the head tissue and its scattering properties, particularly for the shorter interfibre distances.

Dans le « carré de l'activité » : perspectives internationales sur le travail et l'activité

Abstract: Resume Cet article introductif vise a dessiner un espace particulier de recherches sur le travail tel qu’il se fait et qui caracterise la maniere dont les ethnographies des situations de travail se developpent sur le plan international. Cet espace est decrit comme un « carre », borde par quatre perspectives : la cognition distribuee, la « theorie de l’activite », l’ethnomethodologie et les courants qui s’en inspirent et la sociologie des sciences et des techniques. Apres avoir expose leurs principes, l’article se donne pour objet de les confronter et de souligner les tensions et les differences qui se font jour entre elles sur plusieurs points critiques pour l’analyse des situations de travail : la maniere de constituer des donnees de terrain, le role respectif des personnes et des choses, leur posture par rapport a la dialectique de la continuite et du changement. Il aborde enfin la maniere dont le developpement actuel des technologies d’information et de communication constitue un point d’entree permettant de reinterroger ces differentes perspectives et de suggerer des debordements ou des reconfigurations possibles.

Lactate and Amino Acid Catabolism in the Cheese-Ripening Yeast Yarrowia lipolytica

Abstract: The consumption of lactate and amino acids is very important for microbial development and/or aroma production during cheese ripening. A strain of Yarrowia lipolytica isolated from cheese was grown in a liquid medium containing lactate in the presence of a low (0.1×) or high (2×) concentration of amino acids. Our results show that there was a dramatic increase in the growth of Y. lipolytica in the medium containing a high amino acid concentration, but there was limited lactate consumption. Conversely, lactate was efficiently consumed in the medium containing a low concentration of amino acids after amino acid depletion was complete. These data suggest that the amino acids are used by Y. lipolytica as a main energy source, whereas lactate is consumed following amino acid depletion. Amino acid degradation was accompanied by ammonia production corresponding to a dramatic increase in the pH. The effect of adding amino acids to a Y. lipolytica culture grown on lactate was also investigated. Real-time quantitative PCR analyses were performed with specific primers for five genes involved in amino acid transport and catabolism, including an amino acid transporter gene (GAP1) and four aminotransferase genes (ARO8, ARO9, BAT1, and BAT2). The expression of three genes involved in lactate transport and catabolism was also studied. These genes included a lactate transporter gene (JEN1) and two lactate dehydrogenase genes (CYB2-1 and CYB2-2). Our data showed that GAP1, BAT2, BAT1, and ARO8 were maximally expressed after 15 to 30 min following addition of amino acids (BAT2 was the most highly expressed gene), while the maximum expression of JEN1, CYB2-1, and CYB2-2 was delayed (≥60 min).

Radiographic Outcomes of Adult Spinal Deformity Correction: A Critical Analysis of Variability and Failures Across Deformity Patterns

Abstract: Study Design: Multicenter, prospective, consecutive, surgical case series from the International Spine Study Group. Objectives: To evaluate the effectiveness of surgical treatment in restoring spinopelvic (SP) alignment. Summary of Background Data: Pain and disability in the setting of adult spinal deformity have been correlated with global coronal alignment (GCA), sagittal vertical axis (SVA), pelvic incidence/lumbar lordosis mismatch (PI-LL), and pelvic tilt (PT). One of the main goals of surgery for adult spinal deformity is to correct these parameters to restore harmonious SP alignment. Methods: Inclusion criteria were operative patients (age greater than 18 years) with baseline (BL) and 1-year full-length X-rays. Thoracic and thoracolumbar Cobb angle and previous mentioned parameters were calculated. Each parameter at BL and 1 year was categorized as either pathological or normal. Pathologic limits were: Cobb greater than 30 � , GCA greater than 40 mm, SVA greater than 40 mm, PI-LL greater than 10 � , and PT greater than 20 � . According to thresholds, corrected or worsened alignment groups of patients were identified and overall radiographic effectiveness of procedure was evaluated by combining the results from the coronal and sagittal planes.