Georges Friedel Laboratory

Convolutional Neural Networks (CNN) has achieved a great success in image recognition task by automatically learning a hierarchical feature representation from raw data. While the majority of Time-Series Classification (TSC) literature is focused on 1D signals, this paper uses Recurrence Plots (RP) to transform time-series into 2D texture images and then take advantage of the deep CNN classifier. Image representation of time-series introduces different feature types that are not available for 1D signals, and therefore TSC can be treated as texture image recognition task. CNN model also allows learning different levels of representations together with a classifier, jointly and automatically. Therefore, using RP and CNN in a unified framework is expected to boost the recognition rate of TSC. Experimental results on the UCR time-series classification archive demonstrate competitive accuracy of the proposed approach, compared not only to the existing deep architectures, but also to the state-of-the art TSC algorithms.

We investigated the physiological consequences of one of the most extreme exercises realized by humans in race conditions: a 166-km mountain ultra-marathon (MUM) with 9500 m of positive and negative elevation change. For this purpose, (i) the fatigue induced by the MUM and (ii) the recovery processes over two weeks were assessed. Evaluation of neuromuscular function (NMF) and blood markers of muscle damage and inflammation were performed before and immediately following (n = 22), and 2, 5, 9 and 16 days after the MUM (n = 11) in experienced ultra-marathon runners. Large maximal voluntary contraction decreases occurred after MUM (-35% [95% CI: -28 to -42%] and -39% [95% CI: -32 to -46%] for KE and PF, respectively), with alteration of maximal voluntary activation, mainly for KE (-19% [95% CI: -7 to -32%]). Significant modifications in markers of muscle damage and inflammation were observed after the MUM as suggested by the large changes in creatine kinase (from 144 ± 94 to 13,633 ± 12,626 UI L(-1)), myoglobin (from 32 ± 22 to 1,432 ± 1,209 µg L(-1)), and C-Reactive Protein (from <2.0 to 37.7 ± 26.5 mg L(-1)). Moderate to large reductions in maximal compound muscle action potential amplitude, high-frequency doublet force, and low frequency fatigue (index of excitation-contraction coupling alteration) were also observed for both muscle groups. Sixteen days after MUM, NMF had returned to initial values, with most of the recovery process occurring within 9 days of the race. These findings suggest that the large alterations in NMF after an ultra-marathon race are multi-factorial, including failure of excitation-contraction coupling, which has never been described after prolonged running. It is also concluded that as early as two weeks after such an extreme running exercise, maximal force capacities have returned to baseline.

Road information has a fundamental role in modern society. Road extraction from optical satellite images is an economic and efficient way to obtain and update a transportation database. This paper presents an integrated method to extract urban main-road centerlines from satellite optical images. The proposed method has four main steps. First, general adaptive neighborhood is introduced to implement spectral-spatial classification to segment the images into two categories: road and nonroad groups. Second, road groups and homogeneous property, measured by local Geary's C, are fused to improve road-group accuracy. Third, road shape features are used to extract reliable road segments. Finally, local linear kernel smoothing regression is performed to extract smooth road centerlines. Road networks are then generated using tensor voting. The proposed method is tested and subsequently validated using a large set of multispectral high-resolution images. A comparison with several existing methods shows that the proposed method is more suitable for urban main-road centerline extraction.

Luminescent lanthanide(III)-based molecular scaffolds hold great promises for materials science and for biological applications. Their fascinating photophysical properties enable spectral discrimination of emission bands that range from the visible to the near-infrared (NIR) regions. In addition, their strong resistance to photobleaching makes them suitable for long duration or repeated biological experiments using a broad range of sources of excitation including intense and focalized systems such as lasers (e.g., confocal microscopy). A main challenge in the creation of luminescent lanthanide(III) complexes lies in the design of a ligand framework that combines two main features: (i) it must include a chromophoric moiety that possesses a large molar absorptivity and is able to sensitize several different lanthanide(III) ions emitting in the visible and/or in the near-infrared, and (ii) it must protect the Ln(3+) cation by minimizing nonradiative deactivation pathways due to the presence of -OH, -NH and -CH vibrations. Herein, a new family of luminescent Ga(3+)/Ln(3+) metallacrown (MC) complexes is reported. The MCs with the general composition [LnGa4(shi)4(C6H5CO2)4(C5H5N) (CH3OH)] (Ln-1, Ln = Sm(3+)-Yb(3+)) were synthesized in a one pot reaction using salicylhydroxamic acid (H3shi) with Ga(3+) and Ln(3+) nitrates as reagents. The molecular structure of [DyGa4(shi)4(C6H5CO2)4(C5H5N) (CH3OH)] was obtained by X-ray analysis of single crystals and shows that the complex is formed as a [12-MCGa(III)shi-4] core with four benzoate molecules bridging the central Dy(3+) ion to the Ga(3+) ring metals. The powder X-ray diffraction analysis demonstrates that all other isolated complexes are isostructural. The extended analysis of the luminescence properties of these complexes, excited by the electronic states of the chromophoric ligands, showed the presence of characteristic, sharp f-f transitions that can be generated not only in the NIR (Sm, Dy, Ho, Er, Yb) but also in the visible (Sm, Eu, Tb, Dy, Tm). All Ln-1 complexes possess very high quantum yield values with respect to other literature compounds, indicating a good sensitization efficiency of the [12-MCGa(III)shi-4] scaffold. Especially, as of today, the Yb-1 complex exhibits the highest NIR quantum yield reported for a lanthanide(III) complex containing C-H bonds with a value of 5.88(2)% in the solid state. This work is a significant step forward toward versatile, easily prepared luminescent lanthanide(III) complexes suitable for a variety of applications including highly in demand biological imaging, especially in the NIR domain.

PURPOSE: The influence of the medial patellar ligamentous structures on patellar tracking has rarely been studied. Thus the main purpose of this cadaveric biomechanical study was to determine the influence of the medial patellofemoral (MPFL), medial patellomeniscal (MPML) and medial patellotibial (MPTL) ligaments on the three-dimensional patellar tracking during knee flexion. This study was conducted using a validated cadaveric optoelectronic protocol for analysis of patellar kinematics. METHODS: For each cadaveric knee study, four successive acquisitions were performed; first was studied patellar tracking in healthy knees, then the junction between MPFL and vastus medialis obliquus (VMO) was sectioned, the MPFL was released at its patellar attachment and finally was released the insertion of the MPML and MPTL. RESULTS: In this study, the MPFL accounts for 50-60% of the medial stabilization forces of the lateral patellar shift during patellar engagement in the femoral trochlea. This work confirm and clarify the role of the MPFL as the primary stabilizer of the patella during the initial 30° of knee flexion. Moreover, this study shows no significant results regarding the stabilizing action of the VMO on the patella during knee flexion. CONCLUSION: This in vitro study, conducted with an experimental protocol previously validated in the literature, helps quantify the actions of the MPFL, the VMO, and the MPML/MPTL respectively, and identify areas of joint motion where these structures have the most significant influence. This confirms the importance of reconstruction in the treatment of chronic patellar instability. During its reconstruction, care should be taken to adjust the MPFL balance during the initial 20°-30° of flexion.

SUMMARY Up to now, image processing and image analysis techniques have borrowed their basic tools from functional analysis: Fourier filtering, differential and integral calculus, and so on. These tools, however, only realize their efficiency when they are put into a well‐defined algebraic frame, most of the time of a vectorial nature. Unfortunately, the class of functions modelling ‘images’, commonly referred to as ‘grey tone functions’ does not necessarily present this very type of structure. We present here an operation for the ‘addition’ of two images, with a physical justification in the context of transmitted light. Such an addition permits the construction of the family of ‘positive homothetics' of the grey tone function at hand. The vectorial context sought is well defined: The class of images associated with the class of their grey tone functions naturally becomes the positive cone of an ordered real vector space. Furthermore, the proposed model holds for logarithmic imaging and is compatible with what is known about the human visual process. This model has been called ‘LIP’ (logarithmic image processing model).

BACKGROUND: The effects of L-asparaginase on hemostasis during induction chemotherapy are less defined in adults than in children. We, therefore, studied the effects of L-asparaginase in adult patients. DESIGN AND METHODS: This was a retrospective analysis of 214 patients treated with L-asparaginase (7500 IU/m(2) x 6) for acute lymphoblastic leukemia or lymphoblastic lymphoma. Between day 1 of the induction course and discharge, clinical events, and biological and therapeutic modifications were reviewed. RESULTS: Antithrombin and fibrinogen levels were lower than 60% and 1 g/L in 71% and 73% of patients, respectively. Twenty thromboses occurred in 9.3% of the patients; these patients had a median antithrombin level of 53% (range, 21-111) at the time of the event. Forty-two episodes of bleeding occurred in 31 patients with a median fibrinogen level of 1.3 g/L. Infusions of L-asparaginase were reduced or delayed in 64% of patients due to low fibrinogen and/or antithrombin levels. Fresh-frozen plasma, antithrombin and fibrinogen were infused in 31%, 41% and 52% of patients, respectively. The mean antithrombin and fibrinogen levels increased from 61% to 88% and from 1 to 1.4 g/L after infusion of antithrombin or fibrinogen respectively, while both levels remained unchanged after the infusion of fresh-frozen plasma. In patients who received antithrombin concentrates L-asparaginase injections were less frequently omitted or delayed (53% vs. 72%, p=0.005), the rate of thrombosis was lower (4.8% vs. 12.2%, p=0.04) and the disease-free survival was also reduced (p=0.05). CONCLUSIONS: This retrospective study suggests that antithrombin concentrates may have a beneficial effect on the outcome of adults treated for acute lymphoblastic leukemia with L-asparaginase; prospective studies are essential to confirm this hypothesis.

Most of our knowledge of bone cell physiology is derived from experiments carried out in vitro on polystyrene substrates. However, these traditional monolayer cell cultures do not reproduce the complex and dynamic three-dimensional (3D) environment experienced by cells in vivo. Thus, there is a growing interest in the use of 3D culture systems as tools for understanding bone biology. These in-vitro-engineered systems, less complex than in vivo models, should ultimately recapitulate and control the main biophysical, biochemical, and biomechanical cues that define the in vivo bone environment, while allowing their monitoring. This review focuses on state-of-the-art and the current advances in the development of 3D culture systems for bone biology research. It describes more specifically advantages related to the use of such systems, and details main characteristics and challenges associated with its three main components, that is, scaffold, cells, and perfusion bioreactor systems. Finally, future challenges for noninvasive imaging technologies are addressed.

PURPOSE: To assess numerically the flexibility and mechanical stresses undergone by stents and fabric of currently manufactured stent-grafts. METHODS: Eight marketed stent-graft limbs (Aorfix, Anaconda, Endurant, Excluder, Talent, Zenith Flex, Zenith LP, and Zenith Spiral-Z) were modeled using finite element analysis. A numerical benchmark combining bending up to 180° and pressurization at 150 mmHg of the stent-grafts was performed. Stent-graft flexibility, assessed by the calculation of the luminal reduction rate, maximal stresses in stents, and maximal strains in fabric were assessed. RESULTS: The luminal reduction rate at 90° was <20% except for the Talent stent-graft. The rate at 180° was higher for Z-stented models (Talent, Endurant, Zenith, and Zenith LP; range 39%-78%) than spiral (Aorfix, Excluder, and Zenith Spiral-Z) or circular-stented (Anaconda) devices (range 14%-26%). At 180°, maximal stress was higher for Z-stented stent-grafts (range 370-622 MPa) than spiral or circular-stented endografts (range 177-368 MPa). At 90° and 180°, strains in fabric were low and did not differ significantly among the polyester stent-grafts (range 0.5%-7%), while the expanded polytetrafluoroethylene fabric of the Excluder stent-graft underwent higher strains (range 11%-18%). CONCLUSION: Stent design strongly influences mechanical performances of aortic stent-grafts. Spiral and circular stents provide greater flexibility, as well as lower stress values than Z-stents, and thus better durability.

Abstract Functionally Graded Materials ( FGM s) represent a novel approach for the realization of innovative properties and/or functions that conventional homogeneous materials cannot accomplish. In conventional materials, in fact, the composition or the structure is uniform over the volume; on the opposite, in FGM s such features gradually change from layer to layer, with the aim of realizing a gradation of properties over the volume and performing a set of specified functions. Among FGM s, special attention is given today to Functionally Graded Ceramics ( FGC s), designed and developed to withstand a variety of severe operative conditions, including high temperatures, corrosive environments, abrasion, mechanical, and thermal induced stresses. An important application field of FGC s is for medical prosthetic devices and artificial tissues, taking inspiration from the several examples of living tissues with graded structures. After an introduction on the rationale for using FGC s in the biomedical field, the 3 main types of graded materials developed today (eg, composition, porosity and microstructural graded ceramics) are here reviewed, highlighting the most innovative technologies used to develop them, their potentials and challenging features in comparison with the monolithic counterparts.

International audience

We report the observation of two stellar occultations by Titan on 14 November 2003, using stations in the Indian Ocean, southern Africa, Spain, and northern and southern Americas. These occultations probed altitudes between ∼550 and 250 km (∼1 to 250 μ bar) in Titan's upper stratosphere. The light curves reveal a sharp inversion layer near 515 ± 6 km altitude (1.5 μ bar pressure level), where the temperature increases by 15 K in only 6 km. This layer is close to an inversion layer observed fourteen months later by the Huygens HASI instrument during the entry of the probe in Titan's atmosphere on 14 January 2005 [Fulchignoni et al., 2005]. Central flashes observed during the first occultation provide constraints on the zonal wind regime at 250 km, with a strong northern jet (∼200 m s −1 ) around the latitude 55°N, wind velocities of ∼150 m s −1 near the equator, and progressively weaker winds as more southern latitudes are probed. The haze distribution around Titan's limb at 250 km altitude is close to that predicted by the Global Circulation Model of Rannou et al. (2004) in the southern hemisphere, but a clearing north of 40°N is necessary to explain our data. This contrasts with Rannou et al.'s (2004) model, which predicts a very thick polar hood over Titan's northern polar regions. Simultaneous observations of the flashes at various wavelengths provide a dependence of τ ∝ λ − q , with q = 1.8 ± 0.5 between 0.51 and 2.2 μ m for the tangential optical depth of the hazes at 250 km altitude.

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Abstract The non-oscillatory central difference scheme of Nessyahu and Tadmor, in which the resolution or Riemann problems at the cell interfaces is by-passed thanks to the use of the staggered Lax-Friedrichs scheme, is extended here to a two-step, two-dimensional non-oscillatory centered scheme in finite volume formulation. The construction of the scheme rests on a finite volume extension of the Lax-Friedrichs scheme, in which the finite volume cells are the barycentric cells constructed around the nodes of an FEM triangulation, for odd time steps, and some quadrilateral cells associated with this triangulation, for even time steps. Piecewise linear cell interpolants using least-squares gradients combined with a van Leer-type slope limiting allow for an oscillation-free second-order resolution. Some preliminary numerical experiments suggest that two-dimensional problems can be handled very efficiently by the method presented here. Keywords: Hyperbolic conservation lawsfinite volumesunstructured staggered gridsMUSCL interpolantsslope limiterscompressible flows

Blood platelets are first aimed at ensuring primary hemostasis. Beyond this role, they have been acknowledged as having functions in the maintenance of the vascular arborescence and, more recently, as being also innate immune cells, devoted notably to the detection of danger signals, of which infectious ones. Platelets express pathogen recognition receptors that can sense bacterial and viral moieties. Besides, several molecules that bind epithelial or sub-endothelial molecules and, so forth, are involved in hemostasis, happen to be able to ligate viral determinants, making platelets capable of either binding viruses or even to be infected by some of them. Further, as platelets express both Fc-receptors for Ig and complement receptors, they also bind occasionally virus-Ig or virus-Ig-complement immune complexes. Interplays of viruses with platelets are very complex and viral infections often interfere with platelet number and functions. Through a few instances of viral infections, the present review aims at presenting some of the most important interactions from pathophysiological and clinical points of view, which are observed between human viruses and platelets.

In April 2013, a symposium was organized to highlight different aspects of differentiation and activation of the monocyte-macrophage lineage as analyzed on the flow cytometer. Characterization of this lineage requires knowledge of the maturation process from their progenitors that are present in bone marrow up to the mature monocytic cells in peripheral blood, because each monocytic lineage cell with an aberrant phenotype refers to the corresponding maturation stage. A standardized quantitative analysis will facilitate the monitoring of the pathological processes and the clinical features, such as the outcome of treatment. However, changes in marker expression by variation in intensity, asynchronism, and lineage infidelity must be considered. The dynamics of normal marker expressions in early differentiation stages, e.g. molecules like HLA II, CD64 or CD14, give rise to a hypothesis on their possible role in monocyte ontogeny. Besides their usual role in tissue homeostasis, mature macrophages may also play a similar role in hematopoiesis. This meeting highlighted the large potential of flow cytometric tools available for monitoring of all these aspects in the monocytic and macrophage cell lineage. © 2015 International Clinical Cytometry Society.

We test relationships between structure of acoustic signal used for individual recognition and nesting ecology among two gulls: the black-headed gull (Larus ridibundus), in which chicks remain in the nest, and the slender-billed gull (L. genei), in which chicks leave the nest after hatching to form crèches. A striking difference between both species is the presence of two fundamental frequencies in the slender-billed gull's call and only one in the black-headed gull's call. Our study shows that the potential for individuality coding is more important in the species where the offspring experiment the greatest constraints--due to their nesting pattern--to identify their parents.

Prediction of migration from packaging to food is often made using equations which are not always designed specifically for the problem. At least, these equations should overestimate migration, in order to be on the safe side. Integration of Fick's equation under the assumption of 'infinite packaging' provides an equation which is very practical since it requires only a few experimental data. It is shown here that, unfortunately, the use of this equation leads to a systematic underestimation of the diffusivity, by the square of the percentage of migration at steady state. In contrast to widely accepted opinion, this model is not conservative. A conservative approach requires that the diffusivity is determined under 'finite packaging' assumptions, associated with very large volumes of food and with long term experiments. These equations are applied to the migration of a phenolic antioxidant from polypropylene.

Logarithmic images, such as images obtained by transmitted light or those produced by the human visual system, differ from linear images. Their processing and analysis require consequently specific laws and structures. The latter have been developed in the concept of a logarithmic image processing (LIP) model (Jourlin & Pinoli, 1987, 1988; Pinoli, 1987a). This model permits the introduction of a well-justified contrast definition: from a physical point of view, it is closely linked with logarithmic images and from a mathematical point of view, it is set up in an algebraic structure. The applications presented at the end of this paper concern image preprocessing and segmentation. In particular, in the case of microscopic images, the proposed method of segmentation gives good results with transmitted light (thin foils in biology or transmitted electronic microscopy). However, images obtained by reflected light microscopy are not within the scope of this model.

In recent years, printed and flexible gas sensors have quickly emerged as an innovative area of great interest because of their lightness and low cost.