Showing papers by "ParisTech published in 2017"

Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer

Abstract: To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC.

Theoretical guarantees for approximate sampling from smooth and log‐concave densities

Abstract: Sampling from various kinds of distributions is an issue of paramount importance in statistics since it is often the key ingredient for constructing estimators, test procedures or confidence intervals. In many situations, the exact sampling from a given distribution is impossible or computationally expensive and, therefore, one needs to resort to approximate sampling strategies. However, there is no well-developed theory providing meaningful nonasymptotic guarantees for the approximate sampling procedures, especially in the high-dimensional problems. This paper makes some progress in this direction by considering the problem of sampling from a distribution having a smooth and log-concave density defined on Rp, for some integer p > 0. We establish nonasymptotic bounds for the error of approximating the true distribution by the one obtained by the Langevin Monte Carlo method and its variants. We illustrate the effectiveness of the established guarantees with various experiments. Underlying our analysis are insights from the theory of continuous-time diffusion processes, which may be of interest beyond the framework of distributions with log-concave densities considered in the present work.

Biomimetics: process, tools and practice.

Abstract: Biomimetics applies principles and strategies abstracted from biological systems to engineering and technological design. With a huge potential for innovation, biomimetics could evolve into a key process in businesses. Yet challenges remain within the process of biomimetics, especially from the perspective of potential users. We work to clarify the understanding of the process of biomimetics. Therefore, we briefly summarize the terminology of biomimetics and bioinspiration. The implementation of biomimetics requires a stated process. Therefore, we present a model of the problem-driven process of biomimetics that can be used for problem-solving activity. The process of biomimetics can be facilitated by existing tools and creative methods. We mapped a set of tools to the biomimetic process model and set up assessment sheets to evaluate the theoretical and practical value of these tools. We analyzed the tools in interdisciplinary research workshops and present the characteristics of the tools. We also present the attempt of a utility tree which, once finalized, could be used to guide users through the process by choosing appropriate tools respective to their own expertize. The aim of this paper is to foster the dialogue and facilitate a closer collaboration within the field of biomimetics.

Lipolysis and metabolism of fatty acids in cheese

Abstract: Enzymatic hydrolysis (lipolysis) of milk glycerides to free fatty acids is essential for flavor development in cheese. The principal lipolytic agents in cheese include lipoprotein lipase from raw milk, pregastric esterase in cheeses made using rennet paste, and enzymes from the starter and nonstarter microbiota. Lactic acid bacteria are weakly lipolytic and mainly possess nonlipolytic esterases located intracellularly. Lipolysis level is, thus, low in many internal bacterially ripened cheeses. It is higher in certain varieties, such as Swiss cheese, smear-ripened, and particularly mold-ripened cheeses, in which specific lipolytic secondary microbiota develops. Exogenous lipases are occasionally used to develop flavor. Short-chain fatty acids directly contribute to flavor, but fatty acids can also act as precursors for the production of a wide range of other flavor compounds, such as esters, lactones, and methylketones that are associated with diverse flavors. Methods for determining levels of fatty acids are also discussed.

Tailoring residual stress profile of Selective Laser Melted parts by Laser Shock Peening

Abstract: The paper describes a new approach in controlling and tailoring residual stress profile of parts made by Selective Laser Melting (SLM) SLM parts are well known for the high tensile stresses in the as – built state in the surface or subsurface region These stresses have a detrimental effect on the mechanical properties and especially on the fatigue life Laser Shock Peening (LSP) as a surface treatment method was applied on SLM parts and residual stress measurements with the hole – drilling method were performed Two different grades of stainless steel were used: a martensitic 15-5 precipitation hardenable PH1 and an austenitic 316L Different LSP parameters were used, varying laser energy, shot overlap, laser spot size and treatments with and without an ablative medium For both materials the as-built (AB) residual stress state was changed to a more beneficial compressive state The value and the depth of the compressive stress was analyzed and showed a clear dependence on the LSP processing parameters Application of LSP on SLM parts showed promising results, and a novel method that would combine these two processes is proposed The use of LSP during the building phase of SLM as a “3D LSP” method would possibly give the advantage of further increasing the depth and volume of compressive residual stresses, and selectively treating key areas of the part, thereby further increasing fatigue life

Evolution of copper resistance in the kiwifruit pathogen Pseudomonas syringae pv. actinidiae through acquisition of integrative conjugative elements and plasmids

Abstract: Horizontal gene transfer can precipitate rapid evolutionary change. In 2010 the global pandemic of kiwifruit canker disease caused by Pseudomonas syringae pv. actinidiae (Psa) reached New Zealand. At the time of introduction, the single clone responsible for the outbreak was sensitive to copper, however, analysis of a sample of isolates taken in 2015 and 2016 showed that a quarter were copper resistant. Genome sequences of seven strains showed that copper resistance - comprising czc/cusABC and copABCD systems - along with resistance to arsenic and cadmium, was acquired via uptake of integrative conjugative elements (ICEs), but also plasmids. Comparative analysis showed ICEs to have a mosaic structure, with one being a tripartite arrangement of two different ICEs and a plasmid that were isolated in 1921 (USA), 1968 (NZ) and 1988 (Japan), from P. syringae pathogens of millet, wheat and kiwifruit respectively. Two of the Psa ICEs were nearly identical to two ICEs isolated from kiwifruit leaf colonists prior to the introduction of Psa into NZ. Additionally, we show ICE transfer in vitro and in planta, analyze fitness consequences of ICE carriage, capture the de novo formation of novel recombinant ICEs, and explore ICE host-range.

Salivary biomarkers in the diagnosis of breast cancer: A review.

Abstract: Salivary biomarkers could be helpful to characterize breast cancer. Therefore, this review was performed to evaluate the capability of salivary biological markers in the diagnosis and monitoring of breast cancer. Studies were eligible for inclusion if they assessed the potential diagnostic value or other discriminatory properties of biological markers in saliva of patients with breast cancer. The search was performed in six electronic databases (Cochrane, LILACS, PubMed, Science Direct, Scopus, Web of Science). In addition the biomarkers were classified according to their potential clinical application. We identified 567 pertinent studies, of which 13 met the inclusion criteria. Combined biomarker approaches demonstrated better ability to predict breast cancer patients than individual biomarkers. As single biomarker, namely proline, reported great capacity in both early and late stage breast cancer diagnosis. Taurine showed interesting capability to identify early breast cancer individuals. Furthermore, valine also demonstrated excellent diagnostic test accuracy for advanced stages of breast cancer. Only seven studies reported sensitivity and specificity (Zhang et al., 2010; Streckfus et al., 2000a; Brooks et al., 2008; Cheng et al., 2015; Bigler et al., 2002; Zhong et al., 2016; Streckfus, 2009), which varied considerably from 50% to 100%, and from 51% to 97%, respectively. In general, salivary biomarkers identified advanced stages of breast cancer better than early stages. There is currently limited evidence to confirm the putative implementation of salivary biomarkers as diagnostic tools for breast cancer. However, current review provides new research directions.

Further and stronger analogy between sampling and optimization: Langevin Monte Carlo and gradient descent

Abstract: In this paper, we revisit the recently established theoretical guarantees for the convergence of the Langevin Monte Carlo algorithm of sampling from a smooth and (strongly) log-concave density. We improve the existing results when the convergence is measured in the Wasserstein distance and provide further insights on the very tight relations between, on the one hand, the Langevin Monte Carlo for sampling and, on the other hand, the gradient descent for optimization. Finally, we also establish guarantees for the convergence of a version of the Langevin Monte Carlo algorithm that is based on noisy evaluations of the gradient

The Notion of Self-aware Computing

Abstract: We define the notion of “self-aware computing” and the relationship of this term to related terms such as autonomic computing, self-management, and similar. The need for a new definition, driven by trends that are only partially addressed by existing areas of research, is motivated. The semantics of the provided definition are discussed in detail examining the selected wording and explaining its meaning to avoid misleading interpretations. This chapter also provides an overview of the existing usage of the term self-aware computing, respectively self-awareness, in related past projects and initiatives.

What is the impact of a spinal fusion on acetabular implant orientation in functional standing and sitting positions

Abstract: Background This study used EOS imaging of primary total hip arthroplasty (THA) patients, with and without predating spinal fusion, to investigate (1) the impact of spinal fusion on acetabular implant anteversion and inclination, and (2) whether more extensive spinal fusion (fusion starting above the thoracolumbar junction or extension of fusion to the sacrum) affects acetabular implant orientation differently than lumbar only spinal fusion. Methods Ninety-three patients had spinal fusion (case group), and 150 patients were without spinal fusion (controls). None of the patients experienced dislocation. The change in sacral slope (SS) and cup orientation from standing to sitting was measured. Results Mean SS change from the standing to sitting positions was -7.9°in the fusion group vs -18.4°in controls (P = .0001). Mean change in cup inclination from the standing to sitting positions was 4.9°in the fusion group vs 10.2°in controls (P = .0001). Mean change in cup anteversion from standing to sitting positions was 7.1°in the fusion group vs 12.1°in controls (P = .0001). For each additional level of spinal fusion, the change in SS from standing to sitting positions decreased by 1.6(95% confidence interval [CI], 2.2073-1.0741), the change in cup inclination decreased by 0.8(95% CI, 0.380-1.203), and the change in cup anteversion decreased by 0.9(95% CI, 0.518-1.352; P Conclusion Patients with spinal fusion demonstrated less adaptability of the lumbosacral junction. Longer spinal fusion or inclusion of the pelvis in the fusion critically impacts hip-spine biomechanics and significantly affects the ability to compensate in the standing-to-sitting transition.

Wind power forecasting-a review of the state of the art

Abstract: This chapter gives an overview over past and present attempts to predict wind power for single turbines, wind, farms or for whole regions, for a few minutes up to a few days ahead. It is based on a survey and report (Giebel et al., 2011) initiated in the frame of the European project ANEMOS, which brought together many groups from Europe involved in the field with long experience in short-term forecasting. It was then continued in the frame of the follow-up European projects SafeWind and ANEMOS.plus, which concentrated respectively on the forecasting of extreme events and the best possible integration of the forecasts in the work flow of end users.

Impact of Postfault Flux Adaptation on Six-Phase Induction Motor Drives With Parallel Converters

Abstract: The redundancy of multiphase drives provides an inherent fault-tolerant capability that is appreciated in applications with a complicated corrective maintenance or safety-critical requirements. Fault restrictions, however, force the system to be reconfigured to operate in a smooth and efficient manner. Previous works have been focused on the optimization of current waveforms to generate an undisturbed operation but still maintaining the prefault rated flux settings. This study shows that efficient controllers can improve the postfault performance in six-phase induction machines supplied by parallel-connected converters if offline optimization is used to obtain a variable reference flux. Theoretical and experimental results confirm that the proposed flux adaptation method provides higher torque/power capability, lower degree of imbalance in the current sharing between windings and efficiency improvement.

Feature guided wave inspection of bond line defects between a stiffener and a composite plate

Abstract: Adhesive bonding is widely used in aerospace composite structures. A continuous well-cured bond can offer good joint strength and improved fatigue and impact resistance, and is therefore crucial to the performance of the entire structure. This paper explores the feasibility of using feature guided waves (FGW) for rapid screening of the bond line between a stiffener and a carbon fiber reinforced polymer (CFRP) composite panel. Such FGWs are capable of focusing the wave energy along the stiffener and the bond layer, with limited radiation to the adjacent plate. The Semi-Analytical Finite Element (SAFE) approach is employed to understand the modal properties of FGWs that exist in the structure, and criteria are suggested to choose proper mode-frequency combination that is sensitive to adhesive defects. A shear horizontal type FGW mode is identified to be well suited, as it is easy to excite, and propagates with little dispersion and relatively low attenuation, while it retains sufficient energy around the bond layer. Both 3D Finite Element (FE) simulations and experiments are performed to study the interaction of the selected FGW mode with defects in the adhesive bond, and the results show excellent agreement. The reflection behavior and the wave-defect resonance phenomenon are investigated, which demonstrate the capability of the FGW for the bond line inspection.

In situ X-ray tomography investigation on damage mechanisms in short glass fibre reinforced thermoplastics: Effects of fibre orientation and relative humidity

Abstract: Damage mechanisms of reinforced polyamide 6,6 have been studied in 3D through in situ X-ray tomography tensile tests 3D pictures of the microstructure have been taken during tensile tests to catch damage evolution in the bulk of material The effects of relative humidity and orientation sampling are particularly investigated in this paper Main mechanisms have been identified such as fibre failure, debonding, damage at fibre ends and matrix damage (cavitation, fibrillation, damage growth) Qualitative observations reveal that the mechanisms are very sensitive to orientation sampling and relative humidity of the specimen A specific procedure was developed to propose a quantitative analysis of the results This analysis shows that identified mechanisms not only have different proportions but also have different kinetics according to relative humidity and orientation sampling of the specimen

Fluorescence eXclusion Measurement of volume in live cells

Abstract: Volume is a basic physical property of cells; however, it has been poorly investigated in cell biology so far, mostly because it is difficult to measure it precisely. Recently, large efforts were made to experimentally measure mammalian cell size and used mass, density, or volume as proxies for cell size. Here, we describe a method enabling cell volume measurements for single living cells. The method is based on the principle of fluorescent dye exclusion and can be easily implemented in cell biology laboratories. As this method is very versatile, it can be used for cells of different sizes, adherent or growing in suspension, over several cell cycles and is independent of cell shape changes. The method is also compatible with traditional cell biology tools such as epifluorescence imaging or drug treatments.

Micellar catalysis-enabled sustainable ppm Au-catalyzed reactions in water at room temperature

Abstract: Several ppm level gold-catalyzed reactions enabled by the ligand HandaPhos can be performed at room temperature in aqueous nanoreactors composed of the surfactant Nok. Variously substituted allenes undergo cycloisomerization leading to heterocyclic products in good yields. Likewise, cyclodehydration is also illustrated under similar conditions, as is an intermolecular variant, hydration of terminal alkynes. Recycling of the catalyst and reaction medium is also illustrated. A low E factor associated with limited solvent use and therefore, waste generation, documents the greenness of this process.

Fast Langevin based algorithm for MCMC in high dimensions

Abstract: We introduce new Gaussian proposals to improve the efficiency of the standard Hastings-Metropolis algorithm in Markov chain Monte Carlo (MCMC) methods, used for the sampling from a target distribution in large dimension $d$. The improved complexity is $\mathcal{O}(d^{1/5})$ compared to the complexity $\mathcal{O}(d^{1/3})$ of the standard approach. We prove an asymptotic diffusion limit theorem and show that the relative efficiency of the algorithm can be characterised by its overall acceptance rate (with asymptotical value 0.704), independently of the target distribution. Numerical experiments confirm our theoretical findings.

Generalized Kubo formulas for the transport properties of incommensurate 2D atomic heterostructures

Abstract: We give an exact formulation for the transport coefficients of incommensurate two-dimensional atomic multilayer systems in the tight-binding approximation. This formulation is based upon the C* algebra framework introduced by Bellissard and collaborators [Coherent and Dissipative Transport in Aperiodic Solids, Lecture Notes in Physics (Springer, 2003), Vol. 597, pp. 413–486 and J. Math. Phys. 35(10), 5373–5451 (1994)] to study aperiodic solids (disordered crystals, quasicrystals, and amorphous materials), notably in the presence of magnetic fields (quantum Hall effect). We also present numerical approximations and test our methods on a one-dimensional incommensurate bilayer system.