Pierre and Marie Curie University , also known as University of Paris VI , is a public research university located on the Jussieu Campus in the Latin Quarter of the 5th arrondissement of Paris, France.It was established in 1971 following the division of the University of Paris , and is a principal heir to Faculty of science of the University of Paris . The French cultural revolution of 1968, commonly known as "the French May", resulted in the division of the world's second oldest academic institution, the University of Paris, into thirteen autonomous universities.UPMC is the largest scientific and medical complex in France, active in many fields of research with scope and achievements at the highest level, as demonstrated by the many awards regularly won by UPMC researchers, and the many international partnerships it maintains across all five continents. Several university rankings have regularly put UPMC at the 1st place in France, and it has been ranked as one of the top universities in the world. The ARWU has ranked UPMC as the 1st in France, 6th in Europe and 35th in the world and also 4th in field of mathematics, 25th in field of physics, 14th in field of natural science and 32nd in field of engineering, technology and computer science.It has more than 125 laboratories, most of them in association with the Centre national de la recherche scientifique . Some of its most notable institutes and laboratories include the Institut Henri Poincaré, Institut d'Astrophysique de Paris, Laboratoire d'informatique de Paris 6 , Institut de mathématiques de Jussieu and the Laboratoire Kastler-Brossel .The University's Faculty of Medicine Pierre and Marie Curie is located in the teaching hospitals Pitié-Salpêtrière and Saint-Antoine .UPMC delivers a diploma in physics in English, since September 2013 for Université Paris-Sorbonne Abou Dhabi. Wikipedia.
Van Der Aa F.,University Hospitals Leuven |
Drake M.J.,Bristol Urological Institute |
Kasyan G.R.,Moscow State University |
Petrolekas A.,Henri Dynant Hospital |
Cornu J.-N.,University Pierre and Marie Curie
European Urology | Year: 2013
Context: The artificial urinary sphincter (AUS) has historically been considered the gold standard for the surgical management of non-neurogenic stress urinary incontinence (SUI) in men. As new surgical alternatives attempt to offer alternatives to treat male SUI, a contemporary assessment of the evidence supporting the use of AUS appears mandatory for clinical decision making. Objective: To conduct a critical systematic review of long-term outcomes after AUS implantation in male patients with non-neurogenic SUI. Evidence acquisition: A literature search was conducted in PubMed/Medline and Embase databases using the keywords urinary incontinence and urinary sphincter, artificial and male, restricted to articles published in Dutch, English, French, and German between 1989 and 2011. Studies were included if they reported outcomes after AUS implantation in patients with non-neurogenic SUI with a minimum follow-up of 2 yr. Studies with heterogeneous populations were included if information about non-neurogenic patients was displayed separately. Evidence synthesis: Twelve reports were identified, gathering data about 623 patients. Only three studies were prospective. Continence, evaluated only by patient-reported pad use and various questionnaires, was achieved in 61-100% of cases (no pad or one pad per day). Dry rates (no pad) were only available in seven studies and varied from 4% to 86%. A pooled analysis showed that infection or erosion occurred in 8.5% of cases (3.3-27.8%), mechanical failure in 6.2% of cases (2.0-13.8%), and urethral atrophy in 7.9% (1.9-28.6%). Reoperation rate was 26.0% (14.8-44.8%). Patient satisfaction was evaluated in four studies with four different tools and seems to improve after AUS implantation. Conclusions: Quality of evidence supporting the use of AUS in non-neurogenic male patients with SUI is low, based on heterogeneous data, low-quality studies, and mostly out-of-date efficacy outcome criteria. AUS outcomes need to be revisited to be compared with new surgical alternatives, all of which should be prospectively evaluated according to current evidence-based medicine standards. © 2012 European Association of Urology.
Pricoupenko L.,University Pierre and Marie Curie
Physical Review Letters | Year: 2013
The many-boson problem in the presence of an asymptotically narrow Feshbach resonance is considered. The low energy properties are investigated using a two-channel Hamiltonian. The energy spectrum of this model is shown to be bounded from below in the limit of a zero range interaction. This implies the promising possibility of achieving a strongly interacting bosonic phase in a dilute regime where the details of the actual interatomic forces are irrelevant. The integral relation between the energy and the one-body momentum distribution is derived. © 2013 American Physical Society.
Saridakis E.N.,National Technical University of Athens |
Saridakis E.N.,Baylor University |
Saridakis E.N.,University Pierre and Marie Curie
Classical and Quantum Gravity | Year: 2013
We investigate the cosmological evolution in a universe governed by the extended, varying-mass, nonlinear massive gravity, in which the graviton mass is promoted to a scalar field. We find that the dynamics, both in flat and open universe, can lead the varying graviton mass to zero at late times, offering a natural explanation for its hugely constrained observed value. Despite the limit of the scenario toward standard quintessence, at early and intermediate times it gives rise to an effective dark-energy sector of a dynamical nature, which can also lie in the phantom regime, from which it always exits naturally, escaping a Big Rip. Interestingly enough, although the motivation of massive gravity is to obtain an IR modification, its varying-mass extension in cosmological frameworks leads to early and intermediate times modification instead. © 2013 IOP Publishing Ltd.
Cai Y.-F.,McGill University |
Brandenberger R.,McGill University |
Peter P.,University Pierre and Marie Curie
Classical and Quantum Gravity | Year: 2013
Following recent claims relative to the question of large anisotropy production in regular bouncing scenarios, we study the evolution of such anisotropies in a model where an ekpyrotic phase of contraction is followed by domination of a Galileon-type Lagrangian which generates a non-singular bounce. We show that the anisotropies decrease during the phase of ekpyrotic contraction (as expected) and that they can be constrained to remain small during the non-singular bounce phase (a non-trivial result). Specifically, we derive the e-folding number of the phase of ekpyrotic contraction which leads to a present-day anisotropy in agreement with current observational bounds. Communicated by P Singh © 2013 IOP Publishing Ltd.
Pricoupenko L.,University Pierre and Marie Curie
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011
The Bethe-Peierls asymptotic approach which models pairwise short-range forces by contact conditions is introduced in arbitrary representation for spatial dimensions less than or equal to 3. The formalism is applied in various situations and emphasis is put on the momentum representation. In the presence of a transverse harmonic confinement, dimensional reduction toward two-dimensional (2D) or one-dimensional (1D) physics is derived within this formalism. The energy theorem relating the mean energy of an interacting system to the asymptotic behavior of the one-particle density matrix illustrates the method in its second quantized form. Integral equations that encapsulate the Bethe-Peierls contact condition for few-body systems are derived. In three dimensions, for three-body systems supporting Efimov states, a nodal condition is introduced in order to obtain universal results from the Skorniakov-Ter- Martirosian equation and the Thomas collapse is avoided. Four-body bound state eigenequations are derived and the 2D ′ 3+1′ bosonic ground state is computed as a function of the mass ratio. © 2011 American Physical Society.
Leblanc J.L.,University Pierre and Marie Curie
Rubber Chemistry and Technology | Year: 2010
Natural rubber (NR) is by far the most important elastic material but its production specifications remain relatively poor when compared to synthetic elastomers. The so-called technically specified NR grades (i.e., technically specified rubber) are indeed characterized with respect to basic rubber test techniques, such as the Mooney viscosity, the (Wallace) plasticity (P 0), and the Plasticity Retention Index, but high elasticity grades like ribbed smoked sheets are classified with respect to visual inspection criteria only. In addition, NR exhibits by nature more variation than synthetic polymers, owing to inevitable production differences from around 50 different clones of Hevea Brasiliensis, which are further enhanced by climate, soil, and other local effects, as well as seasonal effects on tapping. Most rubber processing operations occur at high rates of strain, and therefore it is essentially the nonlinear viscoelastic response of rubber materials that is of interest. This prompted the development of advanced investigation testing, such as large amplitude oscillatory strain (LAOS) experiments, which over the last decade were developed into powerful techniques to document the nonlinear viscoelastic behavior of polymer materials. First, the standard rheological tests for characterizing gum NR grades are briefly reviewed and discussed. Second, the equipment, test protocols, data treatment, and results modeling necessary to apply nonlinear viscoelastic testing are presented. Third, a number of LAOS experimental results obtained on various grades of NR, on a few chemically modified NR materials, and on two carbon black-filled NR compounds are reported and discussed.
Lacolley P.,University of Lorraine |
Regnault V.,University of Lorraine |
Nicoletti A.,French Institute of Health and Medical Research |
Li Z.,University Pierre and Marie Curie |
Michel J.-B.,French Institute of Health and Medical Research
Cardiovascular Research | Year: 2012
Vascular smooth muscle cells (VSMCs) are the stromal cells of the vascular wall, continually exposed to mechanical signals and biochemical components generated in the blood compartment. They are involved in all the physiological functions and the pathological changes taking place in the vascular wall. Owing to their contractile tonus, VSMCs of resistance vessels participate in the regulation of blood pressure and also in hypertension. VSMCs of conduit arteries respond to hypertension-induced increases in wall stress by an increase in cell protein synthesis (hypertrophy) and extracellular matrix secretion. These responses are mediated by complex signalling pathways, mainly involving RhoA and extracellular signal-regulated kinase1/2. Serum response factor and miRNA expression represent main mechanisms controlling the pattern of gene expression. Ageing also induces VSMC phenotypic modulation that could have influence on cell senescence and loss of plasticity and reprogramming. In the early stages of human atheroma, VSMCs support the lipid overload. Endocytosis/phagocytosis of modified low-density lipoproteins, free cholesterol, microvesicles, and apoptotic cells by VSMCs plays a major role in the progression of atheroma. Migration and proliferation of VSMCs in the intima also participate in plaque progression. The medial VSMC is the organizer of the inwardly directed angiogenic response arising from the adventitia by overexpressing vascular endothelial growth factor in response to lipid-stimulated peroxisome proliferator-activated receptor-γ, and probably also the organizer of the adventitial immune response by secreting chemokines. VSMCs are also involved in the response to proteolytic injury via their ability to activate blood-borne proteases, to secrete antiproteases, and to clear protease/antiprotease complexes. © 2012 The Author.
Mingozzi F.,Childrens Hospital of Philadelphia |
Mingozzi F.,University Pierre and Marie Curie |
High K.A.,Childrens Hospital of Philadelphia |
High K.A.,Howard Hughes Medical Institute |
High K.A.,University of Pennsylvania
Blood | Year: 2013
Gene therapy products for the treatment of genetic diseases are currently in clinical trials, and one of these, an adeno-associated viral (AAV) product, has recently been licensed. AAV vectors have achieved positive results in a number of clinical and preclinical settings, including hematologic disorders such as the hemophilias, Gaucher disease, hemochromatosis, and the porphyrias. Because AAV vectors are administered directly to the patient, the likelihood of a host immune response is high, as shown by human studies. Preexisting and/or recall responses to the wild-type virus from which the vector is engineered, or to the transgene product itself, can interfere with therapeutic efficacy if not identified and managed optimally.Small-scale clinical studies have enabled investigators to dissect the immune responses to the AAV vector capsid and to the transgene product, and to develop strategies to manage these responses to achieve long-term expression of the therapeutic gene. However, a comprehensive understanding of the determinants of immunogenicity of AAV vectors, and of potential associated toxicities, is still lacking. Careful immunosurveillance conducted as part of ongoing clinical studies will provide the basis for understanding the intricacies of the immune response in AAV-mediated gene transfer, facilitating safe and effective therapies for genetic diseases. © 2013 by The American Society of Hematology.
Rutherford A.W.,Imperial College London |
Osyczka A.,Jagiellonian University |
Rappaport F.,University Pierre and Marie Curie
FEBS Letters | Year: 2012
The energy-converting redox enzymes perform productive reactions efficiently despite the involvement of high energy intermediates in their catalytic cycles. This is achieved by kinetic control: with forward reactions being faster than competing, energy-wasteful reactions. This requires appropriate cofactor spacing, driving forces and reorganizational energies. These features evolved in ancestral enzymes in a low O 2 environment. When O 2 appeared, energy-converting enzymes had to deal with its troublesome chemistry. Various protective mechanisms duly evolved that are not directly related to the enzymes' principal redox roles. These protective mechanisms involve fine-tuning of reduction potentials, switching of pathways and the use of short circuits, back-reactions and side-paths, all of which compromise efficiency. This energetic loss is worth it since it minimises damage from reactive derivatives of O 2 and thus gives the organism a better chance of survival. We examine photosynthetic reaction centres, bc 1 and b 6f complexes from this view point. In particular, the evolution of the heterodimeric PSI from its homodimeric ancestors is explained as providing a protective back-reaction pathway. This "sacrifice-of- efficiency-for-protection" concept should be generally applicable to bioenergetic enzymes in aerobic environments. © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Messina R.,University Pierre and Marie Curie |
Antezza M.,CNRS Charles Coulomb Laboratory
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011
We study the radiative heat transfer and the Casimir-Lifshitz force occurring between two bodies in a system out of thermal equilibrium. We consider bodies of arbitrary shape and dielectric properties, held at two different temperatures and immersed in environmental radiation at a third different temperature. We derive explicit closed-form analytic expressions for the correlations of the electromagnetic field and for the heat transfer and Casimir-Lifshitz force in terms of the bodies' scattering matrices. We then consider some particular cases which we investigate in detail: the atom-surface and the slab-slab configurations. © 2011 American Physical Society.
Pricoupenko L.,University Pierre and Marie Curie
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011
The fully variational Hartree-Fock-Bogoliubov approach for bosons is studied in the limit of zero-range forces in two and three dimensions. The equation of state obtained in two dimensions is expressed in a parametric form. It is shown that the Λ potential permits to perform an implicit summation of the ladder diagrams without leaving the variational scheme, restoring thus the consistency of this approximation. © 2011 American Physical Society.
Kronenberg P.,Hospital Prof Doutor Fernando Fonseca |
Traxer O.,University Pierre and Marie Curie
Journal of Urology | Year: 2015
Purpose: We assessed whether stripping and cleaving the laser fiber tip with specialized tools, namely laser fiber strippers, or ceramic or metal scissors, would influence lithotripsy performance. Materials and Methods: Laser fiber tips were stripped with a specialized laser fiber stripper or remained coated. The tips were then cleaved with metal or ceramic scissors. Laser lithotripsy experiments were performed with the 4 fiber tip combinations using an automated laser fragmentation testing system with artificial stones made of plaster of Paris or BegoStone Plus (Bego, Lincoln, Rhode Island). High frequency-low pulse energy (20 Hz and 0.5 J) and low frequency-high pulse energy (5 Hz and 2.0 J) settings were used for 30 seconds. Fissure width, depth and volume, and laser fiber tip photos were analyzed. Results: Coated laser fiber tips always achieved significantly higher ablation volumes (sometimes greater than 50%) than stripped laser fiber tips (p <0.00001) regardless of cleaving scissor type, stone material or lithotripter setting. Coated fiber tips cleaved with metal scissors ablated as well as those cleaved with ceramic scissors (p = 0.16). However, stripped fibers were much less ablative when they were cut with metal scissors compared to ceramic scissors (p <0.00001). Harder stone material decreased ablation volume (p <0.00001). Low frequency-high pulse energy settings were an average of 3 times more ablative than high frequency-low pulse energy settings (p <0.00001). Stripping the fibers, a harder stone material and low frequency-high pulse energy settings were associated with increased fiber tip degradation. Conclusions: Coated laser fibers provided better lithotripsy performance and metal scissors were as good as ceramic scissors to cleave coated fibers. This knowledge may improve and simplify the way that laser lithotripsy procedures are done worldwide. © 2015 American Urological Association Education and Research, Inc.
Rabet N.,University Pierre and Marie Curie
Zoosystema | Year: 2010
Th e egg morphology of Eulimnadia is presented on the basis of samples stored in the Muséum national d'Histoire naturelle, Paris, representing 11 species one of which unidentified. Study of all specimens revealed the presence of nine diff erent egg types. Seven types could clearly be assigned to one species, six of which after eggs produced by the type specimens of the species. In addition, the identification of the specimens labelled "E. colombica" as E. geayi was confirmed, the identification of an E. magdalensis population initially identified as E. compressa was corrected, the species E. chaperi is considered as valid, and a new egg type representing a potential new species was described. Seven instances of contamination from five species were identified, demonstrating that small eggs can easily contaminate samples during collection handling. Advice on museum collection management, a synthesis of the knowledge on egg morphology and an identification key of described Eulimnadia eggs is presented in order to prepare a general revision of this genus based on the egg morphology, which provides informative specific characters. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.
Billen G.,University Pierre and Marie Curie
Philosophical transactions of the Royal Society of London. Series B, Biological sciences | Year: 2013
The nitrogen cycle of pre-industrial ecosystems has long been remarkably closed, in spite of the high mobility of this element in the atmosphere and hydrosphere. Inter-regional and international commercial exchanges of agricultural goods, which considerably increased after the generalization of the use of synthetic nitrogen fertilizers, introduced an additional type of nitrogen mobility, which nowadays rivals the atmospheric and hydrological fluxes in intensity, and causes their enhancement at the local, regional and global scales. Eighty-five per cent of the net anthropogenic input of reactive nitrogen occurs on only 43 per cent of the land area. Modern agriculture based on the use of synthetic fertilizers and the decoupling of crop and animal production is responsible for the largest part of anthropogenic losses of reactive nitrogen to the environment. In terms of levers for better managing the nitrogen cascade, beyond technical improvement of agricultural practices tending to increase nitrogen use efficiency, or environmental engineering management measures to increase nitrogen sinks in the landscape, the need to better localize crop production and livestock breeding, on the one hand, and agriculture and food demand on the other hand, is put forward as a condition to being able to supply food to human populations while preserving environmental resources.
Rotenberg B.,University Pierre and Marie Curie |
Patel A.J.,Rensselaer Polytechnic Institute |
Chandler D.,University of California at Berkeley
Journal of the American Chemical Society | Year: 2011
While individual water molecules adsorb strongly on a talc surface (hydrophilic behavior), a droplet of water beads up on the same surface (hydrophobic behavior). To rationalize this dichotomy, we investigated the influence of the microscopic structure of the surface and the strength of adhesive (surface-water) interactions on surface hydrophobicity. We have shown that at low relative humidity, the competition between adhesion and the favorable entropy of being in the vapor phase determines the surface coverage. However, at saturation, it is the competition between adhesion and cohesion (water-water interactions) that determines the surface hydrophobicity. The adhesive interactions in talc are strong enough to overcome the unfavorable entropy, and water adsorbs strongly on talc surfaces. However, they are too weak to overcome the cohesive interactions, and water thus beads up on talc surfaces. Surprisingly, even talc-like surfaces that are highly adhesive do not fully wet at saturation. Instead, a water droplet forms on top of a strongly adsorbed monolayer of water. Our results imply that the interior of hydrophobic zeolites suspended in water may contain adsorbed water molecules at pressures much lower than the intrusion pressure. © 2011 American Chemical Society.
Jusserand B.,University Pierre and Marie Curie
Applied Physics Letters | Year: 2013
We demonstrate strongly resonant selective interaction between confined excitons and folded acoustic phonons in multi-quantum wells and quantitatively reproduce each scattered spectrum based on the resonant interaction with a single periodized confined exciton. We emphasize the possible impact of these resonances on the generation and detection functions in picosecond acoustics on semiconductor multilayers. © 2013 AIP Publishing LLC.
Brunel N.,University of Chicago |
Hakim V.,University Pierre and Marie Curie |
Richardson M.J.E.,University of Warwick
Current Opinion in Neurobiology | Year: 2014
At the single neuron level, information processing involves the transformation of input spike trains into an appropriate output spike train. Building upon the classical view of a neuron as a threshold device, models have been developed in recent years that take into account the diverse electrophysiological make-up of neurons and accurately describe their input-output relations. Here, we review these recent advances and survey the computational roles that they have uncovered for various electrophysiological properties, for dendritic arbor anatomy as well as for short-term synaptic plasticity. © 2014 Elsevier Ltd.
Authier A.,University Pierre and Marie Curie
Acta Crystallographica Section A: Foundations of Crystallography | Year: 2012
The first attempts at measuring the optical properties of X-rays such as refraction, reflection and diffraction are described. The main ideas forming the basis of Ewalds thesis in 1912 are then summarized. The first extension of Ewalds thesis to the X-ray case is the introduction of the reciprocal lattice. In the next step, the principles of the three versions of the dynamical theory of diffraction, by Darwin, Ewald and Laue, are given. It is shown how the comparison of the dynamical and geometrical theories of diffraction led Darwin to propose his extinction theory. The main optical properties of X-ray wavefields at the Bragg incidence are then reviewed: Pendellösung, shift of the Bragg peak, fine structure of Kossel lines, standing waves, anomalous absorption, paths of wavefields inside the crystal, Borrmann fan and double refraction. Lastly, some of the modern applications of the dynamical theory are briefly outlined: X-ray topography, location of adsorbed atoms at crystal surfaces, optical devices for synchrotron radiation and X-ray interferometry.
Haq B.U.,National Science Foundation |
Haq B.U.,University Pierre and Marie Curie
Global and Planetary Change | Year: 2014
Eustatic sea-level changes of the Cretaceous are reevaluated based on a synthesis of global stratigraphic data. A new terminology for local/regional or relative sea-level changes (eurybatic shifts) is proposed to distinguish them from global (eustatic) sea-level changes, with the observation that all measures of sea-level change in any given location are eurybatic, even when they include a strong global signal. Solid-earth factors that influence inherited regional topography and thus modify physical measures of amplitude of the sea-level rises and falls locally are reviewed. One of these factors, dynamic topography (surface expression of mass flow in the upper mantle on land- and seascapes), is considered most pertinent in altering local measures of amplitude of sea-level events on third-order time scales (0.5-3.0. Myr). Insights gained from these models have led to the reconciliation of variance between amplitude estimates of eurybatic shifts in any given region and global measures of eustatic changes. Global estimates of third-order events can only be guesstimated at best by averaging the eurybatic data from widely distributed time-synchronous events. Revised curves for both long-term and short-term sea-level variations are presented for the Cretaceous Period. The curve representing the long-term envelope shows that average sea levels throughout the Cretaceous remained higher than the present day mean sea level (75-250. m above PDMSL). Sea level reached a trough in mid Valanginian (~. 75. m above PDMSL), followed by two high points, the first in early Barremian (~. 160-170. m above PDMSL) and the second, the highest peak of the Cretaceous, in earliest Turonian (~. 240-250. m above PDMSL). The curve also displays two ~. 20. Myr-long periods of relatively high and stable sea levels (Aptian through early Albian and Coniacian through Campanian). The short-term curve identifies 58 third-order eustatic events in the Cretaceous, most have been documented in several basins, while a smaller number are included provisionally as eustatic, awaiting confirmation. The amplitude of sea-level falls varies from a minimum of ~. 20. m to a maximum of just over 100. m and the duration varies between 0.5 and 3. Myr. The causes for these relatively rapid, and at times large amplitude, sea-level falls in the Cretaceous remain unresolved, although based mainly on oxygen-isotopic data, the presence of transient ice cover on Antarctica as the driver remains in vogue as an explanation. This idea has, however, suffered a recent setback following the discovery of pristine foraminiferal tests in the Turonian of Tanzania whose oxygen-isotopic values show little variation, implying absence of glacioeustasy at least in the Turonian. The prevalence of 4th-order (~. 400. Kyr) cyclicity through most of the Cretaceous (and elsewhere in the Paleozoic, Jurassic and Cenozoic) implies that the periodicity on this time scale, presumably driven by long-term orbital eccentricity, may be a fundamental feature of depositional sequences throughout the Phanerozoic. © 2013.
Dolan J.R.,University Pierre and Marie Curie
Acta Protozoologica | Year: 2010
Tintinnid ciliates, characterized by the possession of a lorica into which the ciliate cell can contract, are a common component of the marine microzooplankton. Lorica architecture and size range widely and classically distinguishes species. Here relationships between ecological parameters and lorica dimensions (lorica oral diameter (LOD), lorica length (LL) and lorica volume (LV) are examined using data from literature reports. The relationships between lorica dimensions and reproductive potential, using maximum reported growth rates of natural populations (n = 52 species) are assessed. Susceptibility to copepod predation and lorica dimensions are considered based on reports of clearance rates of Acartia species feeding on tintinnid ciliates (n = 7 species). Diet and lorica dimension is analyzed using data on mean maximum food size contained in field-caught cells (n = 20 species), and preferred food size based on prey size associated with maximal reported clearance rates (n = 15 species). Overall, LOD is closely related to most of the ecological parameters. Maximum growth rate is related to LOD with smaller LODs corresponding to higher growth rates, in contrast to LL and LV. Maximum prey size is positively related to both LOD and LL but more tightly with LOD. Preferred prey size is positively related to LOD and LV but more tightly related to LOD. Clearance rates of Acartia species feeding on tintinnids are significantly related only to LOD with small LODs corresponding to lower copepod feeding rates. Relationships excluding data on species of Tintinnopsis, the species-rich genus which generally dominates coastal communities, are also examined and show similar trends. In tintinnids, LOD, known to be a conservative and relatively reliable species characteristic, appears related to a wide range of ecological characteristics.
Ciarletta P.,University Pierre and Marie Curie |
Ben Amar M.,University Paris Diderot
Journal of the Mechanics and Physics of Solids | Year: 2012
Constrained growth processes in living materials result in a complex distribution of residual strains, which in certain geometries may induce a bifurcation in the elastic stability. In this work, we investigate the combined effects of growth and material anisotropy in the epithelial pattern formation of tubular tissues. In order to represent the structural organization of most organs, we adopt a strain energy density which accounts for the presence of a nonlinear reinforcement made of cross-ply fibers distributed inside a ground matrix. Using a canonical transformation in mixed polar coordinates, we transform the nonlinear elastic boundary value problem into a variational formulation, performing a straightforward derivation of the EulerLagrange equations for perturbations in circumferential and longitudinal directions. The corresponding curves of marginal stability are obtained numerically: the results demonstrate that both the three-dimensional distribution of residual strains and the mechanical properties of fiber reinforcements within the tissue are fundamental to determine the emergence of a specific instability pattern. In particular, different proportions of axial and circumferential residual strains can model the epithelial formation of mucosal folds in the esophagus and of plicae circulares in the small intestine. The theoretical predictions are compared with morphological data for embryonic intestinal tissues, suggesting that the volumetric growth of the epithelium can also drive the early stages of villi morphogenesis. © 2011 Elsevier Ltd. All rights reserved.
Paulos M.F.,University Pierre and Marie Curie
Journal of High Energy Physics | Year: 2011
We construct a N-function for Lovelock theories of gravity, which yields a holographic c-function in domain-wall backgrounds, and seemingly generalizes the concept for black hole geometries. A flow equation equates the monotonicity properties of N with the gravitational field, which has opposite signs in the domain-wall and black hole backgrounds, due to the presence of negative/positive energy in the former/latter, and accordingly N monotonically decreases/increases from the UV to the IR. On AdS spaces the N-function is related to the Euler anomaly, and at a black hole horizon it is generically proportional to the entropy. For planar black holes, N diverges at the horizon, which we interpret as an order N2 increase in the number of effective degrees of freedom. We show how N can be written as the ratio of the Wald entropy to an effective phase space volume, and using the flow equation relate this to Verlinde's notion of gravity as an entropic force. From the effective phase space we can obtain an expression for the dual field theory momentum cutoff, matching a previous proposal in the literature by Polchinski and Heemskerk. Finally, we propose that the area in Planck units counts states, not degrees of freedom, and identify it also as a phase space volume. Written in terms of the proper radial distance β, it takes the suggestive form of a canonical partition function at inverse temperature β, leading to a "mean energy" which is simply the extrinsic curvature of the surface. Using this we relate this definition of holographic phase space with the effective phase space appearing in the N-function.
Johannes L.,University Pierre and Marie Curie |
Parton R.G.,University of Queensland |
Bassereau P.,French National Center for Scientific Research |
Mayor S.,Institute for Stem Cell Biology and Regenerative Medicine
Nature Reviews Molecular Cell Biology | Year: 2015
How endocytic pits are built in clathrin- and caveolin-independent endocytosis still remains poorly understood. Recent insight suggests that different forms of clathrin-independent endocytosis might involve the actin-driven focusing of membrane constituents, the lectin-glycosphingolipid-dependent construction of endocytic nanoenvironments, and Bin-Amphiphysin-Rvs (BAR) domain proteins serving as scaffolding modules. We discuss the need for different types of internalization processes in the context of diverse cellular functions, the existence of clathrin-independent mechanisms of cargo recruitment and membrane bending from a biological and physical perspective, and finally propose a generic scheme for the formation of clathrin-independent endocytic pits. © 2015 Macmillan Publishers Limited. All rights reserved.
Silveira F.,University Pierre and Marie Curie
Proceedings - IEEE INFOCOM | Year: 2010
Traffic anomaly detection has received a lot of attention over recent years, but understanding the nature of these anomalies and identifying the flows involved is still a manual task, in most cases. We introduce Unsupervised Root Cause Analysis (URCA) which isolates anomalous traffic and classifies alarms with minimal manual assistance and high accuracy. URCA proceeds by successive reduction of the anomalous space, eliminating normal traffic based on feedback from the anomaly detection method. Classification is done by clustering a new anomaly with previously labeled events. We validate URCA using manually analyzed real anomalies as well as synthetic anomaly injection. Our validation shows that URCA can accurately diagnose a large range of anomaly types, including network scans, DDoS attacks, and major routing changes. ©2010 IEEE.
Sakaue T.,Kyushu University |
Brochard-Wyart F.,University Pierre and Marie Curie
ACS Macro Letters | Year: 2014
We propose a novel characterization method of randomly branched polymers based on the geometrical property of such objects in confined spaces. The central idea is that randomly branched polymers exhibit a passing/clogging transition across the nanochannel as a function of the channel size. This critical channel size depends on the degree of the branching, whereby allowing the extraction of the branching information of the molecule. © 2014 American Chemical Society.
Hole S.,University Pierre and Marie Curie
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2012
Through an analysis of different space charge measurement methods, the paper makes recommendations for ensuring optimal implementations and measurements. The thermal, pressure-wave-propagation and pulsed-electro-acoustic methods are considered. From the underlying physics of these methods, the effect of impedance mismatches and measurement conditions are discussed and simple signal treatments are presented taking into account the case of non uniform materials. © 1994-2012 IEEE.
Beaugerie L.,University Pierre and Marie Curie |
Beaugerie L.,University Paris Est Creteil
Digestive Diseases | Year: 2013
Thiopurines promote Epstein-Barr virus-related lymphomas, nonmelanoma skin cancers and acute myeloid leukemias. Anti-tumor necrosis factor (anti-TNF) agents may inhibit or activate carcinogenesis according to the cellular pathways that are activated. A mild increase in the risk of melanoma has been reported in patients exposed to anti-TNF agents. Transplanted patients with previous history of cancer are at high risk of cancer recurrence when receiving posttransplant immunosuppressive therapy, particularly within the first 2 years of treatment. Few data exist for patients with chronic inflammatory disease. In the CESAME cohort that included essentially patients receiving thiopurines, there was no excess incidence of recurrent or new cancer associated with exposure to immunosuppressive therapy in the patients with previous cancer at cohort entry. In clinical practice, the decision to start or resume immunosuppressive therapy in inflammatory bowel disease (IBD) patients with recent cancer should be discussed case by case with cancer specialists. However, taken into account the experience of transplant specialists, it could be suggested not to consider a waiting period for women with adequately treated uterine high-grade cervical dysplasia. For invasive cancers, a waiting period of 2 years should be considered if possible. During this period, treatment of IBD should be restricted to 5-aminosalicylic acid, steroids, nutritional therapy, or surgery, except in case of aggressive IBD that cannot be controlled by these methods. A longer waiting period of 5 years could be recommended for the most aggressive forms of cancers, such as melanomas, aggressive breast cancers, sarcomas, urinary tract cancers, and myelomas. © 2013 S. Karger AG, Basel.
LeFloch P.G.,University Pierre and Marie Curie |
Stewart J.M.,University of Cambridge
Classical and Quantum Gravity | Year: 2011
We investigate the existence and the global causal structure of plane symmetric spacetimes with weak regularity when the matter consists of an irrotational perfect fluid with pressure equal to its mass-energy density. Our theory encompasses the class of W1, 2 regular spacetimes whose metric coefficients have square-integrable first-order derivatives and whose curvature must be understood in the sense of distributions. We formulate the characteristic initial value problem with data posed on two null hypersurfaces intersecting along a two-plane. Relying on Newman-Penrose's formalism and expressing our weak regularity conditions in terms of the Newman-Penrose scalars, we arrive at a fully geometrical formulation in which, along each initial hypersurface, two scalar fields describing the incoming radiation must be prescribed in L1 and W-1, 2, respectively. To analyze the future boundary of such a spacetime and identify its global causal structure, we introduce a gauge that reduces the Einstein equations to a coupled system of wave equations and ordinary differential equations for well-chosen unknowns. We prove that, within the weak regularity class under consideration and for generic initial data, a true spacetime singularity forms in finite proper time. Our formulation is robust enough so that propagating discontinuities in the curvature or in the matter variables do not prevent us from constructing a spacetime whose curvature generically blows up on the future boundary. Earlier work on the problem studied here was restricted to sufficiently regular and vacuum spacetimes. © 2011 IOP Publishing Ltd.
Wheeler M.,University Pierre and Marie Curie
Nuclear Physics B | Year: 2013
We study the scalar product Sl,m between an on-shell and an off-shell Bethe state in models with SU(3)-invariance, where l and m denote the cardinalities of the two sets of Bethe roots. We construct recursion relations relating Sl,m to scalar products of smaller dimension, namely Sl-1,m and Sl,m-1. Solving these recursion relations we obtain new multiple integral expressions for Sl,m, whose integrands are (l+m)×(l+m) determinants, and closely related to the Slavnov determinant expression for the SU(2) scalar product. © 2013 Elsevier B.V.
Paulos M.F.,University Pierre and Marie Curie |
Tolley A.J.,Case Western Reserve University
Journal of High Energy Physics | Year: 2012
We construct a class of theories which extend New Massive Gravity to higher orders in curvature in any dimension. The lagrangians arise as limits of a new class of bimetric theories of Lovelock gravity, which are unitary theories free from the Boulware-Deser ghost. These Lovelock bigravity models represent the most general non-chiral ghostfree theories of an interacting massless and massive spin-two field in any dimension. The scaling limit is taken in such a way that unitarity is explicitly broken, but the Boulware-Deser ghost remains absent. This automatically implies the existence of a holographic c-theorem for these theories. We also show that the Born-Infeld extension of New Massive Gravity falls into our class of models demonstrating that this theory is also free of the Boulware-Deser ghost. These results extend existing connections between New Massive Gravity, bigravity theories, Galileon theories and holographic c-theorems.
Fuster D.,University Pierre and Marie Curie
Journal of Computational Physics | Year: 2013
In this manuscript we propose an energy preserving formulation for the simulation of multiphase flows. The new formulation reduces the numerical diffusion with respect to previous formulations dealing with multiple phases, which makes this method to be especially appealing for turbulent flows. In this work we discuss the accuracy and conservation properties of the method in various scenarios with large density and viscosity jumps across the interface including surface tension effects. © 2012 Elsevier Inc.
Xu H.,Xian Jiaotong University |
Xu H.,University Pierre and Marie Curie |
He Y.,Xian Jiaotong University
Journal of Computational Physics | Year: 2013
Two-level iterative finite element methods are designed to solve numerically the steady 2D/3D Navier-Stokes equations for a large viscosity ν such that a strong uniqueness condition holds. Moreover, the one-level Oseen iterative finite element method based on a fine mesh with small mesh size h is designed to solve numerically the steady 2D/3D Navier-Stokes equations for small viscosity ν such that a weak uniqueness condition holds. Meanwhile, the numerical investigations are provided to show that the proposed methods are efficient for solving the 2D/3D steady Navier-Stokes equations for different viscosities. © 2012 Elsevier Inc.
Aubrun F.,University Claude Bernard Lyon 1 |
Mazoit J.-X.,University Paris - Sud |
Riou B.,University Pierre and Marie Curie
British Journal of Anaesthesia | Year: 2012
Relief of acute pain during the immediate postoperative period is an important task for anaesthetists. Morphine is widely used to control moderate-to-severe postoperative pain and the use of small i.v. boluses of morphine in the post-anaesthesia care unit allows a rapid titration of the dose needed for adequate pain relief. The essential principle of a titration regimen must be to adapt the morphine dose to the pain level. Although morphine would not appear to be the most appropriate choice for achieving rapid pain relief, this is the sole opioid assessed in many studies of immediate postoperative pain management using titration. More than 90 of the patients have pain relief using a protocol of morphine titration and the mean dose required to obtain pain relief is 12 (7) mg, after a median of four boluses. Sedation is frequent during i.v. morphine titration and should be considered as a morphine-related adverse event and not evidence of pain relief. The incidence of ventilatory depression is very low when the criteria to limit the dose of i.v. morphine are enforced. Morphine titration can be used with caution in elderly patients, in children, or in obese patients. In practice, i.v. morphine titration allows the physician to meet the needs of individual patients rapidly and limits the risk of overdose making this method the first step in postoperative pain management. © The Author . Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved.
Debiemme-Chouvy C.,University Pierre and Marie Curie
Biosensors and Bioelectronics | Year: 2010
Pyrrole electrooxidation in the presence of weak-acidic anions allows one to locally, rapidly and in single step form on the electrode a pinhole-free very thin layer of overoxidized polypyrrole (OPPy). This membrane could be really useful for the design of amperometric biosensor based on oxidation of H2O2 generated by an oxidase. Indeed, using rotation disk electrode, the apparent diffusion coefficient of H2O2 within this OPPy film was found to be 10-8cm2s-1, which corresponds to a fast response time of 0.1ms. Moreover, it is shown that with this system, platinum electrode coated with the very thin OPPy membrane, the H2O2 sensitivity is excellent (700nAμM-1cm-2) and the H2O2 selectivity relative to potentially interfering species present in biological fluids, such as ascorbate and dopamine, is very good. Thus, this OPPy membrane which can be locally electrodeposited is ideal for the construction of oxidase-based microbiosensors. © 2010 Elsevier B.V.
Loeuille N.,University Pierre and Marie Curie |
Leibold M.A.,University of Texas at Austin
Ecology Letters | Year: 2014
Local negative feedbacks occur when the occupation of a site by a species decreases the subsequent fitness of related individuals compared to potential competitors. Such negative feedbacks can enhance diversity by changing the spatial structure of the environment. The conditions, however, involve dispersive, environmental and evolutionary processes in complex interactive ways. We introduce a model that accounts for four mechanisms: colonisation-competition-extinction ecological dynamics, evolutionary dynamics, local negative feedbacks and environmental averaging. Three qualitatively distinct dynamics are possible, one dominated by specialists, another dominated by generalists and an intermediate situation exhibiting taxon cycles. We discuss how metacommunity diversity, macro-ecological patterns and environmental patterning are linked to the three qualitative dynamics. The model provides classical shapes for morph-abundance distributions, or diversity-area relationships. Diversity can be high when specialists dominate or when taxon cycles happen. Finally, local negative feedbacks often yield fine-grain environments for taxon cycle dynamics and coarse-grain environments when generalists dominate. © 2014 John Wiley & Sons Ltd/CNRS.
Perinet N.,University of Ontario Institute of Technology |
Juric D.,CNRS Computer Science Laboratory for Mechanics and Engineering Sciences |
Tuckerman L.S.,University Pierre and Marie Curie
Physical Review Letters | Year: 2012
A direct numerical simulation of Faraday waves is carried out in a minimal hexagonal domain. Over long times, we observe the alternation of patterns we call quasihexagons and beaded stripes. The symmetries and spatial Fourier spectra of these patterns are analyzed. © 2012 American Physical Society.
Drewnowski A.,University Pierre and Marie Curie |
Rehm C.D.,University of Washington
American Journal of Clinical Nutrition | Year: 2014
Background: The proposed changes to the Nutrition Facts Label by the US Food and Drug Administration will include information on added sugars for the first time. Objective: The objective was to evaluate the sources of added sugars in the diets of a representative sample of US children and adults by food purchase location and food source (eg, food group). Design: This cross-sectional study among 31,035 children, adolescents, and adults aged ≥6 y from the 2003-2004, 2005-2006, 2007-2008, and 2009-2010 NHANES used data from a 24-h dietary recall to evaluate consumption of added sugars. Food locations of origin were identified as stores (supermarket or grocery store), quick-service restaurants/pizza (QSRs), full-service restaurants (FSRs), schools, and others (eg, vending machines or gifts). Added sugars consumption by food purchase location was evaluated by age, family income-to-poverty ratio, and race-ethnicity. Food group sources of added sugars were identified by using the National Cancer Institute food categories. Results: Added sugars accounted for ∼14.1% of total dietary energy. Between 65% and 76% of added sugars came from stores, 6% and 12% from QSRs, and 4% and 6% from FSRs, depending on age. Older adults (aged ≥51 y) obtained a significantly greater proportion of added sugars from stores than did younger adults. Lower-income adults obtained a significantly greater proportion of added sugars from stores than did higher-income adults. Intake of added sugars did not vary by family income among children/adolescents. Soda and energy and sports drinks were the largest food group sources of added sugars (34.4%), followed by grain desserts (12.7%), fruit drinks (8.0%), candy (6.7%), and dairy desserts (5.6%). Conclusions: Most added sugars came from foods obtained from stores. The proposed changes to the Nutrition Facts Label should capture the bulk of added sugars in the US food supply, which suggests that the recommended changes have the potential to reduce added sugars consumption. © 2014 American Society for Nutrition.
Diagne A.,University Gaston Berger |
Bastin G.,Catholic University of Louvain |
Coron J.-M.,University Pierre and Marie Curie
Automatica | Year: 2012
Explicit boundary dissipative conditions are given for the exponential stability in L2-norm of one-dimensional linear hyperbolic systems of balance laws ∂tξ+Λ ∂xξ-Mξ=0 over a finite interval, when the matrix M is marginally diagonally stable. The result is illustrated with an application to boundary feedback stabilisation of open channels represented by linearised SaintVenantExner equations. © 2011 Elsevier Ltd. All rights reserved.
Liu Q.,CAS Institute of Geology and Geophysics |
Roberts A.P.,Australian National University |
Larrasoaa J.C.,Instituto Geologico Y Minero Of Espana |
Banerjee S.K.,University of Minnesota |
And 3 more authors.
Reviews of Geophysics | Year: 2012
In environmental magnetism, rock and mineral magnetic techniques are used to investigate the formation, transportation, deposition, and postdepositional alterations of magnetic minerals under the influences of a wide range of environmental processes. All materials respond in some way to an applied magnetic field, and iron-bearing minerals are sensitive to a range of environmental processes, which makes magnetic measurements extremely useful for detecting signals associated with environmental processes. Environmental magnetism has grown considerably since the mid 1970s and now contributes to research in the geosciences and in branches of physics, chemistry, and biology and environmental science, including research on climate change, pollution, iron biomineralization, and depositional and diagenetic processes in sediments to name a few applications. Magnetic parameters are used to routinely scan sediments, but interpretation is often difficult and requires understanding of the underlying physics and chemistry. Thorough examination of magnetic properties and of the environmental processes that give rise to the measured magnetic signal is needed to avoid ambiguities, complexities, and limitations to interpretations. In this review, we evaluate environmental magnetic parameters based on theory and empirical results. We describe how ambiguities can be resolved by use of combined techniques and demonstrate the power of environmental magnetism in enabling quantitative environmental interpretations. We also review recent developments that demonstrate the mutual benefit of environmental magnetism from close collaborations with biology, chemistry, and physics. Finally, we discuss directions in which environmental magnetism is likely to develop in the future. © 2012. American Geophysical Union. All Rights Reserved.
Mouret J.-B.,University Pierre and Marie Curie
Studies in Computational Intelligence | Year: 2011
Novelty search is a recent and promising approach to evolve neurocontrollers, especially to drive robots. The main idea is to maximize the novelty of behaviors instead of the efficiency. However, abandoning the efficiency objective(s) may be too radical in many contexts. In this paper, a Pareto-based multi-objective evolutionary algorithmis employed to reconcile novelty search with objective-based optimization by following a multiobjectivization process. Several multiobjectivizations based on behavioral novelty and on behavioral diversity are compared on a maze navigation task. Results show that the bi-objective variant "Novelty + Fitness" is better at fine-tuning behaviors than basic novelty search, while keeping a comparable number of iterations to converge. © 2011 Springer-Verlag Berlin Heidelberg.
Damas A.,University Pierre and Marie Curie
Chirality | Year: 2010
The chiral octahedral bimetallic assemblies [(bpy)(2)Ru(o-L(Ir))][CF(3)SO(3)](2) (2), [(ppy)(2)Rh(o-L(Ir))][NO(3)] (7) and [(ppy)(2)Ir(o-L(Ir))][NO(3)] (8) featuring chelating organometallic linker [Cp*Ir(η(4)-o-benzoquinone)] (o-L(Ir)) have been prepared and fully characterized. Anion metathesis following a convenient procedure allowed the preparation of the related diastereomers [Δ-(bpy)(2)Ru(o-L(Ir))][Δ-TRISPHAT](2) (2a) and [Λ-(bpy)(2)Ru(o-L(Ir))][Δ-TRISPHAT](2) (2b) as well as the octahedral rhodium [(Δ, Λ)-(ppy)(2)Rh(o-L(Ir))][Δ-TRISPHAT] (7a, 7b) and iridium [(Δ, Λ)-(ppy)(2)Ir(o-L(Ir))][Δ-TRISPHAT] (8a, 8b) bimetallic assemblies. (1)H NMR studies in solution carried out on these compounds showed different behavior. For instance, the rhodium and iridium compounds exhibited weak chiral recognition in contrast the ruthenium compounds allowed facile differentiation between the two diastereomers suggesting that chiral recognition occurs between the enantiopure anion and the cationic part of the molecule. © 2010 Wiley-Liss, Inc.
Croce J.C.,University Pierre and Marie Curie |
McClay D.R.,Duke University
Development | Year: 2010
Endomesoderm is the common progenitor of endoderm and mesoderm early in the development of many animals. In the sea urchin embryo, the Delta/ Notch pathway is necessary for the diversification of this tissue, as are two early transcription factors, Gcm and FoxA, which are expressed in mesoderm and endoderm, respectively. Here, we provide a detailed lineage analysis of the cleavages leading to endomesoderm segregation, and examine the expression patterns and the regulatory relationships of three known regulators of this cell fate dichotomy in the context of the lineages. We observed that endomesoderm segregation first occurs at hatched blastula stage. Prior to this stage, Gcm and FoxA are co-expressed in the same cells, whereas at hatching these genes are detected in two distinct cell populations. Gcm remains expressed in the most vegetal endomesoderm descendant cells, while FoxA is downregulated in those cells and activated in the above neighboring cells. Initially, Delta is expressed exclusively in the micromeres, where it is necessary for the most vegetal endomesoderm cell descendants to express Gcm and become mesoderm. Our experiments show a requirement for a continuous Delta input for more than two cleavages (or about 2.5 hours) before Gcm expression continues in those cells independently of further Delta input. Thus, this study provides new insights into the timing mechanisms and the molecular dynamics of endomesoderm segregation during sea urchin embryogenesis and into the mode of action of the Delta/Notch pathway in mediating mesoderm fate.
Sinclair J.C.,Laboratory of Molecular Biophysics |
Davies K.M.,Laboratory of Molecular Biophysics |
Venien-Bryan C.,Laboratory of Molecular Biophysics |
Venien-Bryan C.,University Pierre and Marie Curie |
Noble M.E.M.,Laboratory of Molecular Biophysics
Nature Nanotechnology | Year: 2011
The self-assembly of supramolecular structures that are ordered on the nanometre scale is a key objective in nanotechnology. DNA 1-4 and peptide 5-7 nanotechnologies have produced various two- and three-dimensional structures, but protein molecules have been underexploited in this area of research. Here we show that the genetic fusion of subunits from protein assemblies that have matching rotational symmetry generates species that can self-assemble into well-ordered, pre-determined one- and two-dimensional arrays that are stabilized by extensive intermolecular interactions. This new class of supramolecular structure provides a way to manufacture biomaterials with diverse structural and functional properties. © 2011 Macmillan Publishers Limited. All rights reserved.
Soussi T.,Karolinska Institutet |
Soussi T.,University Pierre and Marie Curie
Advances in Cancer Research | Year: 2011
TP53 mutations are the most frequent genetic alterations found in human cancer. For more than 20. years, TP53 mutation databases have collected over 30,000 somatic mutations from various types of cancer. Analyses of these mutations have led to many types of studies and have improved our knowledge about the TP53 protein and its function. The recent advances in sequencing methodologies and the various cancer genome sequencing projects will lead to a profound shift in database curation and data management. In this paper, we will review the current status of the TP53 mutation database, its application to various fields of research, and how data quality and curation can be improved. We will also discuss how the genetic data will be stored and handled in the future and the consequences for database management. © 2011 Elsevier Inc.
Bauvois B.,University Pierre and Marie Curie
Biochimica et Biophysica Acta - Reviews on Cancer | Year: 2012
This review focuses on matrix metalloproteinases (MMPs)-2 (gelatinase A) and -9 (gelatinase B), both of which are cancer-associated, secreted, zinc-dependent endopeptidases. Gelatinases cleave many different targets (extracellular matrix, cytokines, growth factors, chemokines and cytokine/growth factor receptors) that in turn regulate key signaling pathways in cell growth, migration, invasion, inflammation and angiogenesis. Interactions with cell surface integral membrane proteins (CD44, αVβ/αβ1/αβ2 integrins and Ku protein) can occur through the gelatinases' active site or hemopexin-like C-terminal domain. This review evaluates the recent literature on the non-enzymatic, signal transduction roles of surface-bound gelatinases and their subsequent effects on cell survival, migration and angiogenesis. Gelatinases have long been drug targets. The current status of gelatinase inhibitors as anticancer agents and their failure in the clinic is discussed in light of these new data on the gelatinases' roles as cell surface transducers - data that may lead to the design and development of novel, gelatinase-targeting inhibitors. © 2011 Elsevier B.V.
Baudouin Q.,CNRS Non-Linear Institute of Nice |
Mercadier N.,CNRS Non-Linear Institute of Nice |
Mercadier N.,Saint - Gobain |
Guarrera V.,CNRS Non-Linear Institute of Nice |
And 4 more authors.
Nature Physics | Year: 2013
In conventional lasers optical cavities are used to provide feedback to gain media. Mirrorless lasers can be built by using disordered structures to induce multiple scattering, which increases the path length in the medium, providing the necessary feedback. Interestingly, light or microwave amplification by stimulated emission also occurs naturally in stellar gases 2-4 and planetary atmospheres5,6. The possibility of additional scattering-induced feedback4,7 - random lasing 8-14 - could explain the unusual properties of some space masers 15. Here, we report experimental evidence of random lasing in a controlled, cold atomic vapour, taking advantage of Raman gain. By tuning the gain frequency in the vicinity of a scattering resonance, we observe an enhancement of the light emission due to random lasing. The unique possibility to both control the experimental parameters and to model the microscopic response of our system provides an ideal test bench for better understanding natural lasing sources, in particular the role of resonant scattering feedback in astrophysical lasers. © 2013 Macmillan Publishers Limited. All rights reserved.
Smith K.S.,Courant Institute of Mathematical Sciences |
Bernard E.,University Pierre and Marie Curie
Physics of Fluids | Year: 2013
Geostrophic turbulence near horizontal surfaces on which the vertical velocity vanishes exhibits a forward cascade of buoyancy variance, characterized by a shallow energy spectrum, secondary roll-up of filaments, and a fat-tailed vorticity probability distribution. Such surfaces occur at rigid boundaries, but also at discontinuous jumps in stratification. Here we relax this mathematical idealization and investigate geostrophic turbulence near a rapid but smooth jump in stratification, modeled by N(z) = N0[1 + αtanh (z/h)]. The rapidity of change is controlled by the length scale h and the profile approaches a step function as h → 0. The approximated Green's function for the quasigeostrophic potential vorticity (PV) is used to predict the spectral PV-streamfunction relationship, under various assumptions about the distribution of the initial PV. Numerical simulations of freely-evolving quasigeostrophic turbulence in the presence of the model stratification support the predictions and reveal that the jump has two effects: it alters the Green's function in the region of the jump and it produces a peak in PV near the jump, approaching a Dirac delta-function as the jump scale h → 0. When the Green's function is integrated against this sharp PV distribution, contributions far from the jump (|z| ≫ h) are suppressed and the flow in a region |z| ≲ O(h) exhibits surface effects. This occurs for horizontal scales L ≳ N0h/f, the deformation scale associated with the jump. These results have implications for geostrophic turbulence near the tropopause in the atmosphere and the base of the mixed layer in the ocean. © 2013 American Institute of Physics.
Pawlus S.,University of Silesia |
Klotz S.,University Pierre and Marie Curie |
Paluch M.,University of Silesia
Physical Review Letters | Year: 2013
High pressure viscosity and dielectric measurements were carried out on two monohydroxy alcohols, 2-ethyl-1-hexanol and 5-methyl-2-hexanol, at room temperature. Analysis of the dielectric relaxation times versus viscosity revealed the breakdown of the Einstein-Debye relation above some characteristic pressure. The failure of the Einstein-Debye relation is a manifestation of pressure induced changes of supramolecular hydrogen bonded structures which occur in these liquids. © 2013 American Physical Society.
Otero-De-La-Roza A.,University of California at Merced |
Johnson E.R.,University of California at Merced |
Contreras-Garcia J.,University Pierre and Marie Curie
Physical Chemistry Chemical Physics | Year: 2012
In this article, the NCI method [Johnson et al., J. Am. Chem. Soc., 2010, 132, 6498] for plotting and analysing non-covalent interactions (NCI) is extended to periodic (solid-state) electron densities and implemented in the critic program. The new code uses self-consistent electron densities from a variety of electronic structure methods (pseudopotentials/plane-wave, FP-LAPW, local orbitals, etc.), and it can also build the promolecular density from the crystal geometry alone. As an example of the new code, intermolecular interactions in several molecular crystals are presented and analyzed. The connection with QTAIM studies is established and a reinterpretation of the NCI domains is given regarding the current knowledge of the field. The connection between NCI domains and intermolecular vibrations is made apparent, as well as the ability of the method to reveal the locality of bonding. © This journal is the Owner Societies 2012.
Well-defined critical association concentration and rapid adsorption at the air/water interface of a short amphiphilic polymer, amphipol A8-35: A study by förster resonance energy transfer and dynamic surface tension measurements
Giusti F.,University Paris Diderot |
Popot J.-L.,University Paris Diderot |
Tribet C.,University Pierre and Marie Curie
Langmuir | Year: 2012
Amphipols (APols) are short amphiphilic polymers designed to handle membrane proteins (MPs) in aqueous solutions as an alternative to small surfactants (detergents). APols adsorb onto the transmembrane, hydrophobic surface of MPs, forming small, water-soluble complexes, in which the protein is biochemically stabilized. At variance with MP/detergent complexes, MP/APol ones remain stable even at extreme dilutions. Pure APol solutions self-associate into well-defined micelle-like globules comprising a few APol molecules, a rather unusual behavior for amphiphilic polymers, which typically form ill-defined assemblies. The best characterized APol to date, A8-35, is a random copolymer of acrylic acid, isopropylacrylamide, and octylacrylamide. In the present work, the concentration threshold for self-association of A8-35 in salty buffer (NaCl 100 mM, Tris/HCl 20 mM, pH 8.0) has been studied by Förster resonance energy transfer (FRET) measurements and tensiometry. In a 1:1 mol/mol mixture of APols grafted with either rhodamine or 7-nitro-1,2,3-benzoxadiazole, the FRET signal as a function of A8-35 concentration is essentially zero below a threshold concentration of 0.002 g ·L-1 and increases linearly with concentration above this threshold. This indicates that assembly takes place in a narrow concentration interval around 0.002 g ·L-1. Surface tension measurements decreases regularly with concentration until a threshold of ca. 0.004 g ·L-1, beyond which it reaches a plateau at ca. 30 mN ·m-1. Within experimental uncertainties, the two techniques thus yield a comparable estimate of the critical self-assembly concentration. The kinetics of variation of the surface tension was analyzed by dynamic surface tension measurements in the time window 10 ms-100 s. The rate of surface tension decrease was similar in solutions of A8-35 and of the anionic surfactant sodium dodecylsulfate when both compounds were at a similar molar concentration of n-alkyl moieties. Overall, the solution properties of APol "micelles" (in salty buffer) appear surprisingly similar to those of the micelles formed by small, nonpolymeric surfactants, a feature that was not anticipated owing to the polymeric and polydisperse nature of A8-35. The key to the remarkable stability to dilution of A8-35 globules, likely to include also that of MP/APol complexes, lies accordingly in the low value of the critical self-association concentration as compared to that of small amphiphilic analogues. © 2012 American Chemical Society.
Oshanin G.,University Pierre and Marie Curie |
Rosso A.,University Paris - Sud |
Schehr G.,University Paris - Sud
Physical Review Letters | Year: 2013
We study properties of a random walk in a generalized Sinai model, in which a quenched random potential is a trajectory of a fractional Brownian motion with arbitrary Hurst parameter H, 0
Komajda M.,University Pierre and Marie Curie |
Lam C.S.P.,National University of Singapore
European Heart Journal | Year: 2014
Heart failure with preserved ejection fraction (HFpEF) is now recognized as a major and growing public health problem worldwide. Yet significant uncertainties still surround its pathophysiology and treatment, leaving clinicians in a dilemma regarding its optimal management. Whether HFpEF and heart failure with reduced ejection fraction (HFrEF) are two distinct entities or two ends of a common spectrum remains a matter of debate. In particular, the lack of benefit observed with renin-angiotensin system blockers has raised questions regarding our understanding of the pathophysiology of HFpEF. New paradigms including a prominent role of co-morbidities, inflammation, endothelial dysfunction, and pro-hypertrophic signalling pathways have been proposed. Recent proof-of-concept trials using a phosphodiesterase inhibitor, a mineralocorticoid receptor antagonist, an angiotensin receptor/neprilysin inhibitor, a soluble guanylate cyclase stimulator, or a sino atria, if current blocker provide important insight for the development of novel therapeutic strategies in HFpEF. © 2014 The Author.
Chapelon-Abric C.,University Pierre and Marie Curie
Current Opinion in Pulmonary Medicine | Year: 2013
PURPOSE OF REVIEW: Heart involvement during sarcoidosis is a medical emergency. The review focuses on published data analysis of clinical management and therapy involving a multidisciplinary monitoring of cardiac sarcoidosis. RECENT FINDINGS: With the emergence of new modalities, especially MRI and FDG PET scan, cardiac sarcoidosis is most often suspected and confirmed even in atypical cases. Laboratory investigations may help to diagnose and survey. Cardiac sarcoidosis drastically changes functional and vital prognosis. Recent studies define earlier detrimental predictable criteria to underline how beneficial is the combination of immunosuppressive therapy and cardiac treatment to patients. There are no large prospective studies, but case reports and small series support an appropriate therapeutic approach, which includes corticosteroids and immunosuppressive agents. SUMMARY: Our review illustrates the importance of looking for cardiac sarcoidosis in all sarcoidosis patients and to propose more specific and sensitive investigations when suspected on clinical and/or electrical signs. It emphasizes the need for more adapted criteria and even more prognostic criteria to choose the best therapeutic option. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Pick R.M.,University Pierre and Marie Curie
Physical Review Letters | Year: 2010
A Comment on the Letter by Li-Min Wang and Ranko Richert, Phys Rev. Lett. 99, 185701 (2007). The authors of the Letter offer a Reply. © 2010 The American Physical Society.
Micoulaut M.,University Pierre and Marie Curie |
Malki M.,French National Center for Scientific Research |
Malki M.,University of Orleans
Physical Review Letters | Year: 2010
The ac conductivity spectra of xAgI-(1-x)AgPO3 fast-ion conducting glasses spanning the flexible, intermediate (isostatically rigid), and stressed rigid phases are analyzed. The rescaled frequency-dependent spectra are mapped into time-dependent mean-square displacements out of which a typical length scale characterizing the spatial extent √ R2(∞) of nonrandom subdiffusive regions of ionic motions is computed. The latter quantity is studied as a function of AgI compositions, and is found to display a maximum isostatic compositions, providing the first clear evidence of a typical length scale of a dynamical nature when a system becomes isostatically rigid and enters that phase. © 2010 The American Physical Society.
Capitaine N.,University Pierre and Marie Curie
Research in Astronomy and Astrophysics | Year: 2012
The adoption of the International Celestial Reference System (ICRS), based on Very Long Baseline Interferometry (VLBI) observations of extragalactic radiosources by the International Astronomical Union (IAU) since 1998 January 1, opened a new era for astronomy. The ICRS and the corresponding frame, the International Celestial Reference Frame (ICRF), replaced the Fundamental Catalog (FK5) based on positions and proper motions of bright stars, with the Hipparcos catalog being adopted as the primary realization of the ICRS in optical wavelengths. According to its definition, the ICRS is such that the barycentric directions of distant extragalactic objects show no global rotation with respect to these objects; this provides a quasi-inertial reference for measuring the positions and angular motions of the celestial objects. Other resolutions on reference systems were passed by the IAU in 2000 and 2006 and endorsed by the International Union of Geodesy and Geophysics (IUGG) in 2003 and 2007, respectively. These especially concern the definition and realization of the astronomical reference systems in the framework of general relativity and transformations between them. First, the IAU 2000 resolutions refined the concepts and definition of the astronomical reference systems and parameters for Earth's rotation, and adopted the IAU 2000 precession-nutation. Then, the IAU 2006 resolutions adopted a new precession model that is consistent with dynamical theories; they also addressed definition, terminology or orientation issues relative to reference systems and time scales that needed to be specified after the adoption of the IAU 2000 resolutions. An additional IUGG 2007 resolution defined the International Terrestrial Reference System (ITRS) so that it strictly complies with the IAU recommendations. Finally, the IAU 2009 resolutions adopted a new system of astronomical constants and an improved realization of the ICRF. These fundamental changes have led to significant improvements in the fields of astrometry, celestial mechanics, geodynamics, geodesy, etc. Of special interest are the improvements in the model for variations in Earth's rotation, which, in turn, can provide better knowledge of the dynamics of the Earth's interior. These have also contributed to a significant improvement in the accuracy of the ephemerides of the solar system bodies as determined from modern measurements, with a large number of scientific applications. This paper recalls the main aspects of the recent IAU resolutions on reference systems as well as their consequences on the concepts, definitions, nomenclature and models that are suitable for the definition, realization and transformation of reference frames at a microarcsecond level. © 2012 National Astronomical Observatories of Chinese Academy of Sciences and IOP Publishing Ltd.
Paulos M.F.,University Pierre and Marie Curie
Journal of High Energy Physics | Year: 2011
We investigate the use of the embedding formalism and the Mellin transform in the calculation of tree-level conformal correlation functions in AdS/CFT. We evaluate 5- and 6-point Mellin amplitudes in Φ 3 theory and even a 12-pt diagram in Φ 4 theory, enabling us to conjecture a set of Feynman rules for scalar Mellin amplitudes. The general vertices are given in terms of Lauricella generalized hypergeometric functions. We also show how to use the same combination of Mellin transform and embedding formalism for amplitudes involving field with spin. The complicated tensor structures which usually arise can be written as certain operators acting as projectors on much simpler index structures - essentially the same ones appearing in a at space amplitude. Using these methods we are able to evaluate a four-point current diagram with current exchange in Yang-Mills theory.
Ribe N.M.,University Pierre and Marie Curie |
Habibi M.,Institute for Advanced Studies in Basic Sciences |
Bonn D.,Ecole Normale Superieure de Paris |
Bonn D.,University of Amsterdam
Annual Review of Fluid Mechanics | Year: 2011
A thin stream or rope of viscous fluid falling from a sufficient height onto a surface forms a steadily rotating helical coil. Tabletop laboratory experiments in combination with a numerical model for slender liquid ropes reveal that finite-amplitude coiling can occur in four distinct regimes (viscous, gravitational, inertio-gravitational, and inertial) corresponding to different balances among the three principal forces acting on the rope. The model further shows that the onset of coiling has distinct viscous, gravitational, and inertial modes that connect smoothly with the corresponding finite-amplitude regimes. In addition to steady coiling, slender liquid ropes falling onto surfaces can exhibit a remarkable variety of nonstationary behaviors, including propagating spiral waves of air bubbles, supercoiling, the leaping-shampoo (Kaye) effect for non-Newtonian fluids, and the fluid-mechanical sewing machine in which the rope leaves complex stitch patterns on a moving surface.
Loeuille N.,University Pierre and Marie Curie |
Loeuille N.,French National Institute for Agricultural Research
Ecology Letters | Year: 2010
In randomly assembled communities, diversity is known to have a destabilizing effect. Evolution may affect this result, but our theoretical knowledge of its role is mostly limited to models of small food webs. In the present article, I introduce evolution in a two-species Lotka-Volterra model in which I vary the interaction type and the cost constraining evolution. Regardless of the cost type, evolution tends to stabilize the dynamics more often in trophic interactions than for mutualism or competition. I then use simulations to study the effect of evolution in larger communities that contain all interaction types. Results suggest that evolution usually stabilizes the dynamics. This stabilizing effect is stronger when evolution affects trophic interactions, but happens for all interaction types. Stabilization decreases with diversity and evolution becomes destabilizing in very diverse communities. This suggests that evolution may not counteract the destabilizing effect of diversity observed in random communities. © 2010 Blackwell Publishing Ltd/CNRS.
Letessier-Selvon A.,University Pierre and Marie Curie |
Stanev T.,University of Delaware
Reviews of Modern Physics | Year: 2011
This is a review of the most resent results from the investigation of the ultrahigh energy cosmic rays, particles of energy exceeding 1018eV. After a general introduction to the topic and a brief review of the lower energy cosmic rays and the detection methods, the two most recent experiments, the High Resolution Fly's Eye and the Southern Auger Observatory, are described. Results from these two experiments on the cosmic ray energy spectrum, the chemical composition of these cosmic rays, and searches for their sources are presented. An analysis of the controversies in these results and the projects in development and construction that can help solve the remaining problems with these particles is also presented. © 2011 American Physical Society.
Taddei A.,University Pierre and Marie Curie |
Gasser S.M.,Friedrich Miescher Institute for Biomedical Research
Genetics | Year: 2012
Budding yeast, like other eukaryotes, carries its genetic information on chromosomes that are sequestered from other cellular constituents by a double membrane, which forms the nucleus. An elaborate molecular machinery forms large pores that span the double membrane and regulate the traffic of macromolecules into and out of the nucleus. In multicellular eukaryotes, an intermediate filament meshwork formed of lamin proteins bridges from pore to pore and helps the nucleus reform after mitosis. Yeast, however, lacks lamins, and the nuclear envelope is not disrupted during yeast mitosis. The mitotic spindle nucleates from the nucleoplasmic face of the spindle pole body, which is embedded in the nuclear envelope. Surprisingly, the kinetochores remain attached to short microtubules throughout interphase, influencing the position of centromeres in the interphase nucleus, and telomeres are found clustered in foci at the nuclear periphery. In addition to this chromosomal organization, the yeast nucleus is functionally compartmentalized to allow efficient gene expression, repression, RNA processing, genomic replication, and repair. The formation of functional subcompartments is achieved in the nucleus without intranuclear membranes and depends instead on sequence elements, protein-protein interactions, specific anchorage sites at the nuclear envelope or at pores, and long-range contacts between specific chromosomal loci, such as telomeres. Here we review the spatial organization of the budding yeast nucleus, the proteins involved in forming nuclear subcompartments, and evidence suggesting that the spatial organization of the nucleus is important for nuclear function. © 2012 by the Genetics Society of America.
Billard C.,University Pierre and Marie Curie
Leukemia | Year: 2012
Impaired programmed cell death is an important factor in the pathogenesis of chronic lymphocytic leukemia (CLL) and in the development of resistance to chemoimmunotherapy. Hence, the reactivation of apoptotic processes is likely to be a pertinent strategy for circumventing this resistance. Proteins from the Bcl-2 family are critical elements in defective apoptosis. Some compounds induce the apoptosis of CLL cells ex vivo by downregulation of prosurvival members of this family (for example, Bcl-2 and Mcl-1), whereas others act by upregulation of proapoptotic Bcl-2 homology (BH) 3-only members (for example, Noxa and Bim). The concept of BH3 mimetics was prompted by the fact that BH3-only proteins are specific antagonistic ligands of prosurvival Bcl-2 family members. This led to the design of small molecules capable of inhibiting the activity of prosurvival Bcl-2 proteins and inducing apoptosis in leukemia cells in vitro and antileukemic effects in animal models. Several putative or actual BH3 mimetics are currently being trialed in the clinic. Two novel BH3 mimetics that can specifically bind to and antagonize Mcl-1 (a crucial antiapoptotic factor in CLL) have recently been discovered. The evaluation of this type of compounds clinical impact in CLL can now be considered. © 2012 Macmillan Publishers Limited All rights reserved.
Ratziu V.,University Pierre and Marie Curie |
Goodman Z.,Center for Liver Diseases |
Sanyal A.,Virginia Commonwealth University
Journal of Hepatology | Year: 2015
Of all the aspects of non-alcoholic fatty liver disease (NAFLD), the slowest advances have occurred in the therapeutic field. Thirty-five years after its formal description and after 15 years of intense scrutiny from researchers worldwide, there is still no approved drug for the treatment of non-alcoholic steatohepatits (NASH). In the meantime, progress in the understanding of pathophysiology, diagnosis - both invasive and non-invasive, epidemiology and even natural history have been substantial or, at times, spectacular. In contrast, hepatitis C virus (HCV) therapy underwent constant improvement and even before the great acceleration of the past few years, patients were already being offered approved therapies that were increasingly more efficient. What then explains such a slow pace of therapeutic advances in NASH, and will this change in the near future? Here we will review commonly-held myths that have diverted attention from therapy of NASH, obstacles that have slowed down industrial development of drugs for this indication, and recent achievements that will create better conditions for drug development programs. We will also briefly review current knowledge of non-pharmacological and pharmacological management in this early era of NASH therapies. © 2015 Published by Elsevier B.V. on behalf of the European Association for the Study of the Liver.
Caillot D.,Center Hospitalier Le Bocage |
Stoppa A.M.,Institute Paoli Calmettes |
Hulin C.,Nancy University Hospital Center |
Leyvraz S.,University of Lausanne |
And 2 more authors.
New England Journal of Medicine | Year: 2012
BACKGROUND: High-dose chemotherapy with autologous stem-cell transplantation is a standard treatment for young patients with multiple myeloma. Residual disease is almost always present after transplantation and is responsible for relapse. This phase 3, placebocontrolled trial investigated the efficacy of lenalidomide maintenance therapy after transplantation. METHODS:We randomly assigned 614 patients younger than 65 years of age who had nonprogressive disease after first-line transplantation to maintenance treatment with either lenalidomide (10 mg per day for the first 3 months, increased to 15 mg if tolerated) or placebo until relapse. The primary end point was progression-free survival. RESULTS:Lenalidomide maintenance therapy improved median progression-free survival (41 months, vs. 23 months with placebo; hazard ratio, 0.50; P<0.001). This benefit was observed across all patient subgroups, including those based on the β 2- microglobulin level, cytogenetic profile, and response after transplantation. With a median follow-up period of 45 months, more than 70% of patients in both groups were alive at 4 years. The rates of grade 3 or 4 peripheral neuropathy were similar in the two groups. The incidence of second primary cancers was 3.1 per 100 patient-years in the lenalidomide group versus 1.2 per 100 patient-years in the placebo group (P = 0.002). Median event-free survival (with events that included second primary cancers) was significantly improved with lenalidomide (40 months, vs. 23 months with placebo; P<0.001). CONCLUSIONS:Lenalidomide maintenance after transplantation significantly prolonged progression-free and event-free survival among patients with multiple myeloma. Four years after randomization, overall survival was similar in the two study groups. (Funded by the Programme Hospitalier de Recherche Clinique and others; ClinicalTrials.gov number, NCT00430365.) Copyright © 2012 Massachusetts Medical Society.
Billard C.,French Institute of Health and Medical Research |
Billard C.,University Pierre and Marie Curie
Molecular Cancer Research | Year: 2012
Despite real advances made in chemoimmunotherapy, chronic lymphocytic leukemia (CLL) is still an incurable disease. New therapeutic strategies based on the restoration of the cell death program seemed relevant. Some members of the Bcl-2 family are critical players in the defective apoptotic program in CLL cells and/or targets of apoptosis inducers in vitro. The concept of BH3 mimetics has led to the characterization of small molecules mimicking proapoptotic BH3-only members of the Bcl-2 family by their ability to bind and antagonize the prosurvival members. Some putative or actual BH3 mimetics are already being tested in clinical trials with somewhat promising results. However, none of them has a high enough interaction affinity with Mcl-1, a crucial antiapoptotic factor in CLL. It has been suggested that resistance to BH3 mimetics can be overcome by using inhibitors of Mcl-1 expression. An alternative and more direct strategy is to design mimetics of the Noxa BH3 domain, which is a specific antagonistic Mcl-1 ligand. The development of such Noxa-like BH3 mimetics, capable of directly interacting with Mcl-1 and efficiently neutralizing its antiapoptotic activity, is extremely important to evaluate their impact on the clinical outcome of patients with CLL. ©2012 AACR.
Amouri H.,University Pierre and Marie Curie
Synlett | Year: 2011
Quinone methides (quinomethanes) act as important intermediates in organic syntheses, as well as in chemical and biological processes. However, examples of such isolated species are scarce owing to their high reactivity. Other important reactive intermediates are thio- and selenoquinones. However, unlike quinones, they are highly unstable and consequently do not exist in nature, hence their chemical and biological properties remain unknown. In this account, we describe the first isolation of the above important reactive intermediates, by -coordination to a (pentamethylcyclopentadienyl)iridium (Cp*Ir) moiety, and their X-ray molecular structures. Further, the reactivity of such trapped intermediates is reported. For instance, the metalated o-quinone methide underwent an unusual cycloaddition reaction compared with the free o-quinone methide, while the metalated thioquinones were successfully used as organometallic linkers (OM-linkers) to construct luminescent coordination assemblies. The anticancer activity of the selenoquinone metalated complex was studied, together with related oxygen and sulfur analogues, and remarkably it was shown to be the only cytotoxic compound with a comparable activity to cisplatin. 1 Introduction 2 Quinone Methides 2.1 First Isolation of Metal-Stabilized o-Quinone Methides 2.1.1 Synthesis and Structural Characterization 2.1.2 Reactivity towards Electrophiles and Carbon-Carbon Bond Formation 3 Thioquinones 3.1 First Isolation as Metal Complexes 3.1.1 Synthesis and Structural Characterization 3.1.2 Reactivity as Organometallic Linkers 4 Selenoquinones 4.1 Trapping Selenoquinones as Metal Complexes 4.1.1 Synthesis and Structural Characterization 4.1.2 Biological Properties 5 Concluding Remarks and Future Outlook © Georg Thieme Verlag Stuttgart - New York.
Thebault P.,University Pierre and Marie Curie
Astronomy and Astrophysics | Year: 2012
Context. Debris discs are traditionally studied using two distinct types of numerical models: statistical particle-in-a-box codes to study their collisional and size distribution evolution, and dynamical N-body models to study their spatial structure. The absence of collisions in N-body codes is in particular a major shortcoming, as collisional processes are expected to significantly alter the results obtained from pure N-body runs. Aims. We present a new numerical model, to study the spatial structure of perturbed debris discs in both a dynamical and collisional steady-state. We focus on the competing effects of gravitational perturbations by a massive body (planet or star), the collisional production of small grains, and the radiation pressure placing these grains in possibly dynamically unstable regions. Methods. We consider a disc of parent bodies in a dynamical steady-state, from which small radiation-pressure-affected grains are released in a series of runs, each corresponding to a different orbital position of the perturber, where particles are assigned a collisional destruction probability. These collisional runs produce successive position maps that are then recombined, following a complex procedure, to generate surface density profiles for each orbital position of the perturbing body. Results. We apply our code to the case of a circumprimary disc in a binary. We find pronounced structures inside and outside the dynamical stability regions. For low e B, the disc's structure is time varying, with spiral arms in the dynamically "forbidden" region precessing with the companion star. For high e B, the disc is strongly asymmetric but time invariant, with a pronounced density drop in the binary's periastron direction. © 2012 ESO.
Kronenberg P.,Hospital Professor Doutor Fernando Fonseca |
Traxer O.,University Pierre and Marie Curie
Urology | Year: 2014
Objective To measure the various diameters of laser fibers from various manufacturers and compare them with the advertised diameter. Methods Fourteen different unused laser fibers from 6 leading manufacturers with advertised diameters of 200, 270, 272, 273, 365, and 400 μm were measured by light microscopy. The outer diameter (including the fiber coating, cladding, and core), cladding diameter (including the cladding and the fiber core), and core diameter were measured. Industry representatives of the manufacturers were interviewed about the diameter of their fibers. Results For all fibers, the outer and cladding diameters differed significantly from the advertised diameter (P <.00001). The outer diameter, which is of most practical relevance for urologists, exhibited a median increase of 87.3% (range, 50.7%-116.7%). The outer, cladding, and core diameters of fibers with equivalent advertised diameters differed by up to 180, 100, and 78 μm, respectively. Some 200-μm fibers had larger outer diameters than the 270- to 273-μm fibers. All packaging material and all laser fibers lacked clear and precise fiber diameter information labels. Of 12 representatives interviewed, 8, 3, and 1 considered the advertised diameter to be the outer, the cladding, and the core diameter, respectively. Representatives within the same company frequently gave different answers. Conclusion This study suggests that, at present, there is a lack of uniformity between laser fiber manufacturers, and most of the information conveyed to urologists regarding laser fiber diameter may be incorrect. Because fibers larger than the advertised laser fibers are known to influence key interventional parameters, this misinformation can have surgical repercussions. © 2014 Elsevier Inc.
Levy M.,University Pierre and Marie Curie
ICES Journal of Marine Science | Year: 2015
The critical depth hypothesis (CDH) is a predictive criteria for the onset of phytoplankton blooms that comes from the steady-state analytical solution of a simple mathematical model for phytoplankton growth presented by Sverdrup in 1953. Sverdrup's phytoplankton-only model is very elementary compared with state-of-the-art ecosystem models whose numerical solution in a time-varying environment do not systematically conform to the CDH. To highlight which model ingredients make the bloom onset deviate from the CDH, the complexity of Sverdrup's model is incrementally increased, and the impact that each new level of complexity introduced is analysed. Complexity is added both to the ecosystem model and to the parameterization of physical forcing. In the most complete experiment, the model is a one-dimensional Nutrient-Phytoplankton-Zooplankton model that includes seasonally varying mixed layer depth and surface irradiance, light and nutrient limitation, variable grazing, self-shading, export, and remineralization. When complexity is added to the ecosystem model, it is found that the model solution only marginally deviates from the CDH. But when the physical forcing is also changed, the model solution can conform to two competing theories for the onset of phytoplankton blooms - the critical turbulence hypothesis and the disturbance recovery hypothesis. The key roles of three physical ingredients on the bloom onset are highlighted: the intensity of vertical mixing at the end of winter, the seasonal evolution of the mixed-layer depth from the previous summer, and the seasonal evolution of surface irradiance. © 2015 International Council for the Exploration of the Sea. All rights reserved.
Berthier L.,French National Center for Scientific Research |
Tarjus G.,University Pierre and Marie Curie
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010
In its common implementation, the mode-coupling theory of the glass transition predicts the time evolution of the intermediate scattering functions in viscous liquids on the sole basis of the structural information encoded in two-point density correlations. We provide a critical test of this property and show that the theory fails to describe the strong differences of dynamical behavior seen in two model liquids characterized by very similar pair-correlation functions. Because we use "exact" static information provided by numerical simulations, our results are a direct indication that some important information about the dynamics of viscous liquids is not captured by pair correlations and is thus not described by the mode-coupling theory, even in the temperature regime where the theory is usually applied. © 2010 The American Physical Society.
Deheuvels P.,University Pierre and Marie Curie
Kybernetika | Year: 2011
We consider, in the framework of multidimensional observations, nonparametric functional estimators, which include, as special cases, the Akaike-Parzen-Rosenblatt kernel density estimators ([1, 18, 20]), and the Nadaraya-Watson kernel regression estimators ([16, 22]). We evaluate the sup-norm, over a given set I, of the difference between the estimator and a non-random functional centering factor (which reduces to the estimator mean for kernel density estimation). We show that, under suitable general conditions, this random quantity is consistently estimated by the sup-norm over I of the difference between the original estimator and a bootstrapped version of this estimator. This provides a simple and flexible way to evaluate the estimator accuracy, through a single bootstrap. The present work generalizes former results of Deheuvels and Derzko , given in the setup of density estimation in ℝ.
Saadoun D.,University Pierre and Marie Curie
Arthritis care & research | Year: 2010
To investigate the efficacy and tolerance of azathioprine in severe uveitis related to Behçet's disease (BD). We reported 157 consecutive patients with severe uveitis (active posterior uveitis or panuveitis) fulfilling the international criteria for BD and treated with corticosteroids (0.5-1 mg/kg/day) and azathioprine (2.5 mg/kg/day). Long-term outcome and factors associated with complete remission were assessed. Mean±SD age at diagnosis was 29.9±10.1 years, with 71.3% men. At baseline, 59 patients (37.6%) had loss of useful vision, 54 (34.4%) had retinal vasculitis, 66 (42.0%) had panuveitis, and 132 (84.1%) had bilateral uveitis. Following azathioprine therapy, 81 patients (51.6%) were complete responders, 65 (41.4%) were partial responders, and 11 (7%) were nonresponders. The visual acuity significantly improved (P<0.001), and a significant decrease in the mean oral prednisone dosage (55.3 to 10.5 mg/day; P<0.001) was observed after therapy. Patients with retinal vasculitis (odds ratio [OR] 0.45 [95% confidence interval (95% CI) 0.2-0.9], P=0.02) and severe visual loss (OR 0.28 [95% CI 0.2-0.7], P<0.0001) at diagnosis were less likely to be complete responders. Azathioprine was well tolerated, with only 3 withdrawals due to hepatotoxic effects (n=2) and bacterial septicemia (n=1). Azathioprine represents an effective and safe therapy in patients with severe uveitis of BD. Copyright © 2010 by the American College of Rheumatology.
Behnia K.,University Pierre and Marie Curie
Physical Review Letters | Year: 2010
A Comment on the Letter by Babak Seradjeh, Jiansheng Wu, and Philip Phillips, Phys. Rev. Lett. 103, 136803 (2009)PRLTAO0031-900710.1103/PhysRevLett. 103.136803. The authors of the Letter offer a Reply. © 2010 The American Physical Society.
Canet L.,CNRS Physics and Models in Condensed Media Laboratory |
Chate H.,CEA Saclay Nuclear Research Center |
Delamotte B.,University Pierre and Marie Curie |
Wschebor N.,University of the Republic of Uruguay
Physical Review Letters | Year: 2010
We present a simple approximation of the nonperturbative renormalization group designed for the Kardar-Parisi-Zhang equation and show that it yields the correct phase diagram, including the strong-coupling phase with reasonable scaling exponent values in physical dimensions. We find indications of a possible qualitative change of behavior around d=4. We discuss how our approach can be systematically improved. © 2010 The American Physical Society.
Baigl D.,Ecole Normale Superieure de Paris |
Baigl D.,University Pierre and Marie Curie |
Baigl D.,CNRS PASTEUR Laboratory
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2012
Using light to control liquid motion is a new paradigm for the actuation of microfluidic systems. We review here the different principles and strategies to induce or control liquid motion using light, which includes the use of radiation pressure, optical tweezers, light-induced wettability gradients, the thermocapillary effect, photosensitive surfactants, the chromocapillary effect, optoelectrowetting, photocontrolled electroosmotic flows and optical dielectrophoresis. We analyze the performance of these approaches to control using light many kinds of microfluidic operations involving discrete pL- to μL-sized droplets (generation, driving, mixing, reaction, sorting) or fluid flows in microchannels (valve operation, injection, pumping, flow rate control). We show that a complete toolbox is now available to control microfluidic systems by light. We finally discuss the perspectives of digital optofluidics as well as microfluidics based on all optical fluidic chips and optically reconfigurable devices. © 2012 The Royal Society of Chemistry.
Flandre P.,University Pierre and Marie Curie
PLoS ONE | Year: 2011
Background: In recent years the "noninferiority" trial has emerged as the new standard design for HIV drug development among antiretroviral patients often with a primary endpoint based on the difference in success rates between the two treatment groups. Different statistical methods have been introduced to provide confidence intervals for that difference. The main objective is to investigate whether the choice of the statistical method changes the conclusion of the trials. Methods: We presented 11 trials published in 2010 using a difference in proportions as the primary endpoint. In these trials, 5 different statistical methods have been used to estimate such confidence intervals. The five methods are described and applied to data from the 11 trials. The noninferiority of the new treatment is not demonstrated if the prespecified noninferiority margin it includes in the confidence interval of the treatment difference. Results: Results indicated that confidence intervals can be quite different according to the method used. In many situations, however, conclusions of the trials are not altered because point estimates of the treatment difference were too far from the prespecified noninferiority margins. Nevertheless, in few trials the use of different statistical methods led to different conclusions. In particular the use of "exact" methods can be very confusing. Conclusion: Statistical methods used to estimate confidence intervals in noninferiority trials have a strong impact on the conclusion of such trials. © 2011 Philippe Flandre.
Galayko D.,University Pierre and Marie Curie |
Basset P.,University Paris Est Creteil
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2011
This paper reports on a new approach for the analysis and design of vibration-to-electricity converters [vibration energy harvesters (VEHs)] operating in the mode of strong electromechanical coupling. The underlying concept is that the mechanical impedance is defined for a nonlinear electromechanical transducer on the basis of an equivalence between electrical and mechanical systems. This paper demonstrates how the mechanical impedance of the transducer depends not only on the geometry and the nature of the electromechanical transducer itself but also on the topology and on the operation mode of the conditioning circuit. The analysis is developed for resonant harvesters and is based on the first-harmonic method. It is applied to three electrostatic harvesters using an identical conditioning circuit but employing transducers with different geometries. For each of the three configurations, the mechanical impedance of the transducer is calculated and then used to determine the optimal electrical operation mode of the conditioning circuit, allowing a desired amplitude of the mobile-mass vibration to be obtained. This paper highlights how the parameters of the conditioning circuit and of the transducer impact the transducer's mechanical impedance, directly affecting the impedance matching between the energy source (resonator) and the transducer. This technique permits the design of highly efficient VEHs whatever the means of transduction. © 2011 IEEE.
Moszkowicz D.,University Pierre and Marie Curie
Journal of visceral surgery | Year: 2013
Ischemic colitis (IC) is a rare condition. As ischemia is often transient and clinical symptoms are reversible, its exact incidence is unknown. In current clinical practice, two types of IC are described according to the severity: severe IC, with transmural colonic ischemia and/or multi-organ failure (MOF), and mild IC, without MOF and spontaneous favourable evolution in most cases. Two clinical contexts are encountered: spontaneous IC (SIC) and postoperative IC (POIC), mainly after aortic surgery. As there is no specific clinico-biologic symptom of IC, emergent CT-scan and rectosigmoidoscopy are required for diagnosis confirmation, surgical decision and prognosis analysis. IC surgical treatment is not consensual but can be standardized according to organ function and the degree of ischemia: surgical treatment in case of colonic necrosis with deep ischemia and/or MOF; observation for superficial ischemia without organ dysfunction; systematic medical care. Surgery is required in 20% of cases, and consists in extended colectomy without continuity restoration and prophylactic cholecystectomy. Continuity restoration is feasible in one third of survivors, who are exposed to a high risk of severe cardiovascular events. Copyright © 2013 Elsevier Masson SAS. All rights reserved.
Cazabat A.-M.,University Pierre and Marie Curie |
Guena G.,University of Rennes 1
Soft Matter | Year: 2010
This review is aimed at presenting the evaporation of macroscopic sessile droplets on inert substrates in normal atmosphere in simple cases, as a basis for more complex analyses. © 2010 The Royal Society of Chemistry.
Gas B.,University Pierre and Marie Curie
IEEE Transactions on Neural Networks | Year: 2010
In this paper, we propose an extension of a self-organizing map called self-organizing multilayer perceptron (SOMLP) whose purpose is to achieve quantization of spaces of functions. Based on the use of multilayer perceptron networks, SOMLP comprises the unsupervised as well as supervised learning algorithms. We demonstrate that it is possible to use the commonly used vector quantization algorithms (LVQ algorithms) to build new algorithms called functional quantization algorithms (LFQ algorithms). The SOMLP can be used to model nonlinear and/or nonstationary complex dynamic processes, such as speech signals. While most of the functional data analysis (FDA) research is based on B-spline or similar univariate functions, the SOMLP algorithm allows quantization of function with high dimensional input space. As a consequence, classical FDA methods can be outperformed by increasing the dimensionality of the input space of the functions under analysis. Experiments on artificial and real world examples are presented which illustrate the potential of this approach. © 2006 IEEE.
Alric J.,University Pierre and Marie Curie
Photosynthesis Research | Year: 2010
Cyclic electron flow around PSI, or cyclic photophosphorylation, is the photosynthetic process which recycles the reducing equivalents produced by photosystem I in the stroma towards the plastoquinone pool. Through the activity of cytochrome b 6f, which also transfers protons across the membrane, it promotes the synthesis of ATP. The literature dealing with cyclic electron flow in unicellular algae is far less abundant than it is for plants. However, in the chloroplast of algae such as Chlorella or Chlamydomonas, an efficient carbohydrate catabolism renders the redox poise much more reducing than in plant chloroplasts. It is therefore worthwhile highlighting the specific properties of unicellular algae because cyclic electron flow is highly dependent upon the accumulation of these stromal reducing equivalents. Such an increase of reducing power in the stroma stimulates the reduction of plastoquinones, which is the limiting step of cyclic electron flow. In anaerobic conditions in the dark, this reaction can lead to a fully reduced plastoquinone pool and induce state transitions, the migration of 80% of light harvesting complexes II and 20% of cytochrome b 6f complex from the PSII-enriched grana to the PSI-enriched lamella. These ultrastructural changes have been proposed to further enhance cyclic electron flow by increasing PSI antenna size, and forming PSI-cyt b 6f supercomplexes. These hypotheses are discussed in light of recently published data. © Springer Science+Business Media B.V. 2010.
Johnson X.,University Pierre and Marie Curie
Plant Molecular Biology | Year: 2011
The nuclear factor, Maturation/stability of RbcL (MRL1), regulates the accumulation of the chloroplast rbcL gene transcript in Chlamydomonas reinhardtii by stabilising the mRNA via its 5′ UTR. An absence of MRL1 in algal mrl1 mutants leads to a complete absence of RuBisCO large subunit protein and thus a lack of accumulation of the RuBisCO holoenzyme. By complementing mrl1 mutants by random transformation of the nuclear genome with the MRL1 cDNA, different levels of rbcL transcript accumulate. We also observe that RuBisCO Large Subunit accumulation is perturbed. Complemented strains accumulating as little as 15% RuBisCO protein can grow phototrophically while RuBisCO in this range is limiting for phototrophic growth. We also observe that photosynthetic activity, here measured by the quantum yield of PSII, appears to be a determinant for phototrophic growth. In some strains that accumulate less RuBisCO, a strong production of reactive oxygen species is detected. In the absence of RuBisCO, oxygen possibly acts as the PSI terminal electron acceptor. These results show that random transformation of MRL1 into mrl1 mutants can change RuBisCO accumulation allowing a range of phototrophic growth phenotypes. Furthermore, this technique allows for the isolation of strains with low RuBisCO, within the range of acceptable photosynthetic growth and reasonably low ROS production. MRL1 is thus a potential tool for applications to divert electrons away from photosynthetic carbon metabolism towards alternative pathways. © 2011 Springer Science+Business Media B.V.
Thibault N.,Copenhagen University |
Gardin S.,University Pierre and Marie Curie
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010
The response of calcareous nannofossils to the end-Cretaceous warming is investigated in the Tropical Pacific DSDP Site 577A (Shatsky Rise) through the record of species richness, Shannon diversity, distribution patterns and statistical treatments. This event is marked by a strong acme of the tropical species Micula murus and is accompanied by a decrease of Placozygus spiralis, the disappearance of Biscutum constans and a decrease in bulk δ13C, indicative of a decrease in primary productivity. An increase in abundance of other Micula species at Site 577A and a drop in species richness recorded in all sites of Shatsky Rise, suggest stressed environmental conditions coincident with the end-Cretaceous warming. The acme of M. murus at Shatsky Rise and in the Atlantic Ocean is recorded within magnetochron C29r and correlates (1) with the intense warming as expressed in intermediate waters through the δ18O of benthic foraminifera, and in surface waters through poleward migration, reduced diversity and dwarfism in planktonic foraminifer assemblages, (2) with a sharp decline in marine 187Os/188Os, chemical marker of Deccan volcanic activity, and (3) with a rise in the atmospheric pCO2 record of terrestrial plants in Texas, USA, probably triggered by Deccan volcanic degassing. However, a drop of calcareous nannofossil cool-water taxa in the Equatorial and South Atlantic, as well as a first rise in abundance of M. murus in the South Atlantic and Tropical Pacific occur in the topmost part of chron C30n, and correlates with the rise in palaeotemperature record of terrestrial plants in North Dakota, USA. This suggests that initiation of the warming in the atmosphere and surface waters may predate the striking warming of intermediate water masses by 150/200 kyr. The coincidence and the links between climate change, volcanism, geochemical and biotic events at the end of the Maastrichtian thus remain to be fully elucidated. © 2010 Elsevier B.V. All rights reserved.
Hirsch E.C.,University Pierre and Marie Curie |
Hirsch E.C.,French National Institute for Agricultural Research |
Hirsch E.C.,French National Center for Scientific Research |
Jenner P.,Kings College London |
Przedborski S.,Columbia University
Movement Disorders | Year: 2013
Parkinson's disease is a common adult-onset neurodegenerative disorder whose pathogenesis remains essentially unknown. Currently, it is believed that the neurodegenerative process in Parkinson's disease is a combination of both cell-autonomous and non-cell-autonomous mechanisms. Proposed cell-autonomous mechanisms include alterations in mitochondrial bioenergetics, dysregulation of calcium homeostasis, and impaired turnover of mitochondria. As for the proposed non-cell-autonomous mechanisms, they involve prion-like behavior of misfolded proteins and neuroinflammation. This suggests that cell death in Parkinson's disease is caused by a multifactorial cascade of pathogenic events and argues that effective neuroprotective therapy for Parkinson's disease may have to rely on multiple drug interventions. © 2013 Movement Disorders Society.
Delamotte B.,University Pierre and Marie Curie
Lecture Notes in Physics | Year: 2012
We give in these notes a short presentation of both the main ideas underlying Wilson's renormalization group (RG) and their concrete implementation under the form of what is now called the non-perturbative renormalization group (NPRG) or sometimes the functional renormalization group (which can be perturbative). Prior knowledge of perturbative field theory is not required for the understanding of the heart of the article. © 2012 Springer-Verlag Berlin Heidelberg.
Combescot R.,Ecole Normale Superieure de Paris |
Combescot R.,Institut Universitaire de France |
Combescot M.,University Pierre and Marie Curie
Physical Review Letters | Year: 2012
It has been recently suggested that the Bose-Einstein condensate formed by excitons in the dilute limit must be dark, i.e., not coupled to photons. Here, we show that, under a density increase, the dark exciton condensate must acquire a bright component due to carrier exchange in which dark excitons turn bright. This, however, requires a density larger than a threshold which seems to fall in the forbidden region of the phase separation between a dilute exciton gas and a dense electron-hole plasma. The BCS-like condensation which is likely to take place on the dense side, must then have a dark and a bright component-which makes it "gray." It should be possible to induce an internal Josephson effect between these two coherent components, with oscillations of the photoluminescence as a strong proof of the existence for this "gray" BCS-like exciton condensate. © 2012 American Physical Society.
Wallon S.,University Pierre and Marie Curie
Few-Body Systems | Year: 2012
We first present an introduction to the theory of hard exclusive processes. We then illustrate this theory by a few selected examples. The last part is devoted to the most recent developments in the asymptotical energy limit. © 2012 Springer-Verlag.
Jolivet L.,University Pierre and Marie Curie |
Brun J.-P.,CNRS Geosciences Laboratory of Rennes
International Journal of Earth Sciences | Year: 2010
The Aegean region is a concentrate of the main geodynamic processes that shaped the Mediterranean region: oceanic and continental subduction, mountain building, high-pressure and low-temperature metamorphism, backarc extension, post-orogenic collapse, metamorphic core complexes, gneiss domes are the ingredients of a complex evolution that started at the end of the Cretaceous with the closure of the Tethyan ocean along the Vardar suture zone. Using available plate kinematic, geophysical, petrological and structural data, we present a synthetic tectonic map of the whole region encompassing the Balkans, Western Turkey, the Aegean Sea, the Hellenic Arc, the Mediterranean Ridge and continental Greece and we build a lithospheric-scale N-S cross-section from Crete to the Rhodope massif. We then describe the tectonic evolution of this cross-section with a series of reconstructions from ~70 Ma to the Present. We follow on the hypothesis that a single subduction has been active throughout most of the Mesozoic and the entire Cenozoic, and we show that the geological record is compatible with this hypothesis. The reconstructions show that continental subduction (Apulian and Pelagonian continental blocks) did not induce slab break-off in this case. Using this evolution, we discuss the mechanisms leading to the exhumation of metamorphic rocks and the subsequent formation of extensional metamorphic domes in the backarc region during slab retreat. The tectonic histories of the two regions showing large-scale extension, the Rhodope and the Cyclades are then compared. The respective contributions to slab retreat, post-orogenic extension and lower crust partial melting of changes in kinematic boundary conditions and in nature of subducting material, from continental to oceanic, are discussed. © 2008 Springer-Verlag.
Riera P.,University Pierre and Marie Curie
Journal of Sea Research | Year: 2010
The study investigated the trophic ecology of the gastropod Hydrobia ulvae in different habitat types within an intertidal bay. The results point out two major trophic pathways involving H. ulvae in this bay. On the one hand, in sandy/muddy sediments Hydrobia derives most of its energy from allochtonous detritus derived from Enteromorpha sp and the total SOM pool. In addition, in these sediments, the phototrophic purple bacteria mats played a substantial trophic role in the diet of Hydrobia. On the other hand, in a Spartina maritima marsh, the gastropod appears firstly dependent of autochtonous detritus derived from this plant. The minor contribution of microphytobenthos to the diet of Hydrobia is consistent with a relatively low presence of epipelic diatoms at the sampling sites. These results provide evidence that the trophic ecology of H. ulvae inhabiting intertidal sediments is quite plastic and does not necessarily rely primarly on microphytobenthos. Consequently, in a single bay, the small spatial scale variability in the origin and availability of detritus have direct implications on the food incorporation by H. ulvae. © 2009 Elsevier B.V. All rights reserved.
Dotsenko V.S.,University Pierre and Marie Curie
Nuclear Physics B | Year: 2012
We analyze, and prove, the associativity of the new . Z3 parafermionic chiral algebra which has been announced some time ago, with principal parafermionic fields having the conformal dimension . δφ=8/3. In doing so we have developed a new method for analyzing the associativity of a given chiral algebra of parafermionic type, the method which might be of a more general significance than a particular conformal field theory studied in detail in this paper. Still, even in the context of our particular chiral algebra, of . Z3 parafermions with . δφ=8/3, the new method allowed us to give a proof of associativity which we consider to be complete. © 2012 Elsevier B.V.
Seroussi B.,University Pierre and Marie Curie
AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium | Year: 2012
OncoDoc2 is a guideline-based clinical decision support system (CDSS) applied to the management of breast cancer patients. OncoDoc2 has been routinely used during multidisciplinary staff meetings at the Tenon Hospital (Paris, France) for nearly 3 years. Despite the use of the CDSS that reminds physicians of the recommended treatments, the compliance rate of decisions is not 100%. We have used pattern mining techniques in order to elicit patient clinical profiles associated with non-compliance. We quantified each extracted pattern by three measures (support, growth rate, and unexpected rate) and we introduced a score to prune relevant emerging patterns. Non-compliance has concerned elderly patients in pre-surgery decisions, patients with micro invasive tumor in re-excision decisions, and patients HR+ and Her2+ in adjuvant decisions. In all cases, physician non-compliance with guidelines occurs when scientific evidence is lacking.
Minc N.,Columbia University |
Minc N.,National Oceanic and Atmospheric Administration |
Minc N.,University Pierre and Marie Curie |
Burgess D.,Chestnut Hill College |
And 3 more authors.
Cell | Year: 2011
The spatial organization of cells depends on their ability to sense their own shape and size. Here, we investigate how cell shape affects the positioning of the nucleus, spindle and subsequent cell division plane. To manipulate geometrical parameters in a systematic manner, we place individual sea urchin eggs into microfabricated chambers of defined geometry (e.g.; triangles, rectangles, and ellipses). In each shape, the nucleus is positioned at the center of mass and is stretched by microtubules along an axis maintained through mitosis and predictive of the future division plane. We develop a simple computational model that posits that microtubules sense cell geometry by probing cellular space and orient the nucleus by exerting pulling forces that scale to microtubule length. This model quantitatively predicts division-axis orientation probability for a wide variety of cell shapes, even in multicellular contexts, and estimates scaling exponents for length-dependent microtubule forces. © 2011 Elsevier Inc.
Duretz T.,University Pierre and Marie Curie |
Duretz T.,ETH Zurich |
Gerya T.V.,ETH Zurich
Tectonophysics | Year: 2013
Collision between continents can lead to the subduction of continental material. If the crust remains coupled to the downgoing slab, a large buoyancy force is generated. This force slows down convergence and promotes slab detachment. If the crust resists to subduction, it may decouple from the downgoing slab and be subjected to buoyant extrusion. We employ two-dimensional thermo-mechanical modelling to study the importance of crustal rheology on the evolution of subduction-collision systems. We propose simple quantifications of the mechanical decoupling between lithospheric levels (σz.ast;) and the potential for buoyant extrusion of the crust (ξz.ast;). The modelling results indicate that a variable crustal rheological structure results in slab detachment, delamination, or the combination of both mechanisms.A strong crust provides coupling at the Moho (low σz.ast;) and remains coherent during subduction (low ξ). It promotes deep subduction of the crust (180km) and slab detachment. Exhumation occurs in coherent manners via eduction and thrusting. Slab detachment triggers the development of topography (>4.5km) close to the suture. A contrasting style of collision occurs using a weak crustal rheology. Mechanical decoupling at the Moho (high σz.ast;) promotes the extrusion of the crust (high ξ), disabling slab detachment. Ongoing shortening leads to buckling of the crust and development of topography on the lower plate. Collisions involving rheologically layered crust allow decoupling at mid-crustal depths. This structure favours both the extrusion of upper crust and the subduction of the lower crust. Such collisions are successively affected by delamination and slab detachment. Topography develops together with the buoyant extrusion of crust onto the foreland and is further amplified by slab detachment. Our results suggest that the occurrence of both delamination (Apennines) and slab detachment (Himalayas) in orogens may indicate differences in the initial crustal structure of subducting continental plates in these regions. © 2013 Elsevier B.V.
Coulouvrat F.,University Pierre and Marie Curie
Wave Motion | Year: 2012
Various scalar equations are proposed, modeling the pressure field in the linear and nonlinear acoustical regimes. They are derived by assuming a flow with a small Mach number and a smaller medium heterogeneity. Such assumptions are well satisfied in the atmospheric boundary layer. Further simplifications can be obtained when less intense turbulent fluctuations are superimposed to a sheared mean flow. In the linear regime, a hierarchy of equations with increasing orders of precision is established. A new equation is found where all terms quadratic with respect to the ambient flow are retained, either related to sound convection by the flow, or to the flow inhomogeneity. Numerical solutions indicate that it is more precise than the equations in the literature for small Mach numbers, but less robust for larger negative Mach numbers. Two generalizations of Lilley's equation incorporate the effects of turbulent fluctuations. Nonlinear terms are of different origins, either thermodynamical, inertial, or related to the flow shear. For a locally plane wave, they simplify into a single term which appears as the classical Westervelt quadratic nonlinearity convected by the flow. Consequently, all linear equations can easily be generalized to nonlinear ones, such as a new Lilley's equation augmented with acoustical nonlinearities and turbulent flow fluctuations. © 2011 Elsevier B.V.
Enard D.,Ecole Normale Superieure de Paris |
Depaulis F.,University Pierre and Marie Curie |
Crollius H.R.,Ecole Normale Superieure de Paris
PLoS Genetics | Year: 2010
Among primates, genome-wide analysis of recent positive selection is currently limited to the human species because it requires extensive sampling of genotypic data from many individuals. The extent to which genes positively selected in human also present adaptive changes in other primates therefore remains unknown. This question is important because a gene that has been positively selected independently in the human and in other primate lineages may be less likely to be involved in human specific phenotypic changes such as dietary habits or cognitive abilities. To answer this question, we analysed heterozygous Single Nucleotide Polymorphisms (SNPs) in the genomes of single human, chimpanzee, orangutan, and macaque individuals using a new method aiming to identify selective sweeps genome-wide. We found an unexpectedly high number of orthologous genes exhibiting signatures of a selective sweep simultaneously in several primate species, suggesting the presence of hotspots of positive selection. A similar significant excess is evident when comparing genes positively selected during recent human evolution with genes subjected to positive selection in their coding sequence in other primate lineages and identified using a different test. These findings are further supported by comparing several published human genome scans for positive selection with our findings in non-human primate genomes. We thus provide extensive evidence that the co-occurrence of positive selection in humans and in other primates at the same genetic loci can be measured with only four species, an indication that it may be a widespread phenomenon. The identification of positive selection in humans alongside other primates is a powerful tool to outline those genes that were selected uniquely during recent human evolution. © 2010 Enard et al.
Zorec J.,University Pierre and Marie Curie |
Royer F.,CNRS Galaxies, Stars, Physics and Instrumentation Laboratory
Astronomy and Astrophysics | Year: 2012
Context. In previous works of this series, we have shown that late B-and early A-type stars have genuine bimodal distributions of rotational velocities and that late A-type stars lack slow rotators. The distributions of the surface angular velocity ratio Ω/Ω crit (Ω crit is the critical angular velocity) have peculiar shapes according to spectral type groups, which can be caused by evolutionary properties. Aims. We aim to review the properties of these rotational velocity distributions in some detail as a function of stellar mass and age. Methods. We have gathered vsini for a sample of 2014 B6-to F2-type stars. We have determined the masses and ages for these objects with stellar evolution models. The (T eff,log L/L ⊙)-parameters were determined from the uvby-β photometry and the HIPPARCOS parallaxes. Results. The velocity distributions show two regimes that depend on the stellar mass. Stars less massive than 2.5 M ⊙ have a unimodal equatorial velocity distribution and show a monotonical acceleration with age on the main sequence (MS). Stars more massive have a bimodal equatorial velocity distribution. Contrarily to theoretical predictions, the equatorial velocities of stars from about 1.7 M ⊙ to 3.2 M ⊙ undergo a strong acceleration in the first third of the MS evolutionary phase, while in the last third of the MS they evolve roughly as if there were no angular momentum redistribution in the external stellar layers. The studied stars might start in the ZAMS not necessarily as rigid rotators, but with a total angular momentum lower than the critical one of rigid rotators. The stars seem to evolve as differential rotators all the way of their MS life span and the variation of the observed rotational velocities proceeds with characteristic time scales δt ≈ 0.2 t MS, where t MS is the time spent by a star in the MS. © 2012 ESO.
Razavi H.,Center for Disease Analysis |
Elkhoury A.C.,Sharp Corporation |
Elbasha E.,Sharp Corporation |
Estes C.,Center for Disease Analysis |
And 3 more authors.
Hepatology | Year: 2013
Hepatitis C virus (HCV) infection is a leading cause of cirrhosis, hepatocellular carcinoma, and liver transplantation. A better understanding of HCV disease progression and the associated cost can help the medical community manage HCV and develop treatment strategies in light of the emergence of several potent anti-HCV therapies. A system dynamic model with 36 cohorts was used to provide maximum flexibility and improved forecasting. New infections incidence of 16,020 (95% confidence interval, 13,510-19,510) was estimated in 2010. HCV viremic prevalence peaked in 1994 at 3.3 (2.8-4.0) million, but it is expected to decline by two-thirds by 2030. The prevalence of more advanced liver disease, however, is expected to increase, as well as the total cost associated with chronic HCV infection. Today, the total cost is estimated at $6.5 ($4.3-$8.4) billion and it will peak in 2024 at $9.1 ($6.4-$13.3) billion. The lifetime cost of an individual infected with HCV in 2011 was estimated at $64,490. However, this cost is significantly higher among individuals with a longer life expectancy. Conclusion: This analysis demonstrates that US HCV prevalence is in decline due to a lower incidence of infections. However, the prevalence of advanced liver disease will continue to increase as well as the corresponding healthcare costs. Lifetime healthcare costs for an HCV-infected person are significantly higher than for noninfected persons. In addition, it is possible to substantially reduce HCV infection through active management. © 2013 American Association for the Study of Liver Diseases.
Raynal M.,Institute of Chemical Research of Catalonia |
Raynal M.,University Pierre and Marie Curie |
Ballester P.,Institute of Chemical Research of Catalonia |
Ballester P.,Catalan Institution for Research and Advanced Studies |
And 3 more authors.
Chemical Society Reviews | Year: 2014
Supramolecular catalysis is a rapidly expanding discipline which has benefited from the development of both homogeneous catalysis and supramolecular chemistry. The properties of classical metal and organic catalysts can now be carefully tailored by means of several suitable approaches and the choice of reversible interactions such as hydrogen bond, metal-ligand, electrostatic and hydrophobic interactions. The first part of these two subsequent reviews will be dedicated to catalytic systems for which non-covalent interactions between the partners of the reaction have been designed although mimicking enzyme properties has not been intended. Ligand, metal, organocatalyst, substrate, additive, and metal counterion are reaction partners that can be held together by non-covalent interactions. The resulting catalysts possess unique properties compared to analogues lacking the assembling properties. Depending on the nature of the reaction partners involved in the interactions, distinct applications have been accomplished, mainly (i) the building of bidentate ligand libraries (intra ligand-ligand), (ii) the building of di- or oligonuclear complexes (inter ligand-ligand), (iii) the alteration of the coordination spheres of a metal catalyst (ligand-ligand additive), and (iv) the control of the substrate reactivity (catalyst-substrate). More complex systems that involve the cooperative action of three reaction partners have also been disclosed. In this review, special attention will be given to supramolecular catalysts for which the observed catalytic activity and/or selectivity have been imputed to non-covalent interaction between the reaction partners. Additional features of these catalysts are the easy modulation of the catalytic performance by modifying one of their building blocks and the development of new catalytic pathways/reactions not achievable with classical covalent catalysts. © 2014 The Royal Society of Chemistry.
Caclin A.,University Pierre and Marie Curie
Journal of vision | Year: 2012
Visual shape and motion information, processed in distinct brain regions, should be combined to elicit a unitary coherent percept of an object in motion. In an fMRI study, we identified brain regions underlying the perceptual binding of motion and shape independently of the features-contrast, motion, and shape-used to design the moving displays. These displays alternately elicited a bound (moving diamond) or an unbound (disconnected moving segments) percept, and were either physically unchanging yet perceptually bistable or physically changing over time. The joint analysis of the blood-oxygen-level-dependent (BOLD) signals recorded during bound or unbound perception with these different stimuli revealed a network comprising the occipital lobe and ventral and dorsal visual regions. Bound percepts correlated with in-phase BOLD increases within the occipital lobe and a ventral area and decreased activity in a dorsal area, while unbound percepts elicited moderate BOLD modulations in these regions. This network was similarly activated by bistable unchanging displays and by displays periodically changing over time. The uncovered interplay between the two regions is proposed to reflect a generic binding process that dynamically weights the perceptual evidence supporting the different shape and motion interpretations according to the reliability of the neural activity in these regions.
Raynal M.,Institute of Chemical Research of Catalonia |
Raynal M.,University Pierre and Marie Curie |
Ballester P.,Institute of Chemical Research of Catalonia |
Ballester P.,Catalan Institution for Research and Advanced Studies |
And 3 more authors.
Chemical Society Reviews | Year: 2014
The design of artificial catalysts able to compete with the catalytic proficiency of enzymes is an intense subject of research. Non-covalent interactions are thought to be involved in several properties of enzymatic catalysis, notably (i) the confinement of the substrates and the active site within a catalytic pocket, (ii) the creation of a hydrophobic pocket in water, (iii) self-replication properties and (iv) allosteric properties. The origins of the enhanced rates and high catalytic selectivities associated with these properties are still a matter of debate. Stabilisation of the transition state and favourable conformations of the active site and the product(s) are probably part of the answer. We present here artificial catalysts and biomacromolecule hybrid catalysts which constitute good models towards the development of truly competitive artificial enzymes. © 2014 The Royal Society of Chemistry.
Ribe N.M.,University Pierre and Marie Curie
Geophysical Journal International | Year: 2010
To elucidate the dynamics of free (buoyancy-driven) subduction of oceanic lithosphere, I study a model in which a 2-D sheet of viscous fluid with thickness h and viscosity γη1 subducts in an infinitely deep ambient fluid with viscosity η1. Numerical solutions for the sheet's evolution are obtained using the boundary-element method (BEM), starting from an initial configuration comprising a short 'protoslab' attached to a longer horizontal 'plate' that is free to move laterally beneath an impermeable traction-free surface. Interpretation of the solutions using thin viscous sheet theory shows that the fundamental length scale controlling the subduction is the 'bending length'. ℓb, defined at each instant as the length of the portion of the sheet's midsurface where the rate of change of curvature is significant. Geophysically speaking, ℓb is the sum of the lengths of the slab and of the region seaward of the trench where flexural bulging occurs. The bending length in turn enters into the definition of the sheet's dimensionless 'stiffness'. S≡γ(h/ℓb)3, which controls whether the sinking speed of the slab is determined by the viscosity of the sheet itself (S≫ 1) or by that of the ambient fluid (S≤ 1). Motivated by laboratory observations of different modes of subduction (retreating versus advancing trench, folding versus no folding, etc.) in fluid layers with finite depth, I calculate numerically the dip θD of the slab's leading end as a function of γ and the normalized depth D/h to which it has penetrated. The contours of the function θD(γ, D/h) strongly resemble the intermode boundaries in the laboratory-based regime diagram of Schellart, supporting the hypothesis that the mode of subduction observed at long times in experiments is controlled by the dip of the slab's leading end when it reaches the bottom of the layer. In particular, the BEM solutions explain why trenches advance in the laboratory only when γ lies in an intermediate range, and why they retreat when γ is either smaller or larger than this. Application of the BEM model to Wu et al.'s compilation of the minimum curvature radii of subducted slabs suggests γ∈[140, 510] for the Earth. This is too small to permit the laboratory-type 'trench advancing' mode, in agreement with the lack of tomographic evidence for slabs that are 'bent over backwards'. © 2009 The Author Journal compilation © 2009 RAS.
Dolan J.R.,University Pierre and Marie Curie
ISME Journal | Year: 2016
The latitudinal diversity gradient is a well-known biogeographic pattern. However, rarely considered is how a cline in species richness may be reflected in the characteristics of species assemblages. Fewer species may equal fewer distinct ecological types, or declines in redundancy (species functionally similar to one another) or fewer trace species, those occurring in very low concentrations. We focused on tintinnid ciliates of the microzooplankton in which the ciliate cell is housed inside a species-specific lorica or shell. The size of lorica oral aperture, the lorica oral diameter (LOD), is correlated with a preferred prey size and maximum growth rate. Consequently, species of a distinct LOD are distinct in key ecologic characteristics, whereas those of a similar LOD are functionally similar or redundant species. We sampled from East Sea/Sea of Japan to the High Arctic Sea. We determined abundance distributions of biological species and also ecological types by grouping species in LOD size-classes, sets of ecologically similar species. In lower latitudes there are more trace species, more size-classes and the dominant species are accompanied by many apparently ecologically similar species, presumably able to replace the dominant species, at least with regard to the size of prey exploited. Such redundancy appears to decline markedly with latitude in assemblages of tintinnid ciliates. Furthermore, the relatively small species pools of the northern high latitude assemblages suggest a low capacity to adapt to changing conditions.The ISME Journal advance online publication, 18 March 2016; doi:10.1038/ismej.2016.19. © 2016 International Society for Microbial Ecology
McKinley G.A.,University of Dayton |
Fay A.R.,University of Dayton |
Takahashi T.,Lamont Doherty Earth Observatory |
Metzl N.,University Pierre and Marie Curie
Nature Geoscience | Year: 2011
Oceanic uptake of carbon dioxide substantially reduces the rate at which anthropogenic carbon accumulates in the atmosphere1, slowing global climate change. Some studies suggest that the rate at which the oceans take up carbon has significantly decreased in recent years. Others suggest that decadal variability confounds the detection of long-term trends. Here, we examine trends in the partial pressure of carbon dioxide in the surface waters of three large biogeographic regions in the North Atlantic, using observational data collected between 1981 and 2009. We compare these oceanic observations with trends in atmospheric carbon dioxide levels, taken from a global observational network. We show that trends in oceanic carbon dioxide concentrations are variable on a decadal timescale, often diverging from trends in atmospheric carbon dioxide. However, when the entire 29-year period is considered, oceanic trends converge with atmospheric trends in all three regions; it takes 25 years for this long-term trend to emerge and overcome the influence of decadal-scale variability. Furthermore, in the southernmost biome, the data suggest that warmingg-driven by a multidecadal climate oscillation and anthropogenic forcingg12,13-has started to reduce oceanic uptake of carbon in recent years. © 2011 Macmillan Publishers Limited. All rights reserved.
Ortiz A.U.,Chimie Paristech |
Boutin A.,University Pierre and Marie Curie |
Fuchs A.H.,Chimie Paristech |
Coudert F.-X.,Chimie Paristech
Physical Review Letters | Year: 2012
We performed ab initio calculations of the elastic constants of five flexible metal-organic frameworks (MOFs): MIL-53(Al), MIL-53(Ga), MIL-47, and the square and lozenge structures of DMOF-1. Tensorial analysis of the elastic constants reveals a highly anisotropic elastic behavior, some deformation directions exhibiting very low Young's modulus and shear modulus. This anisotropy can reach a 4001 ratio between the most rigid and weakest directions, in stark contrast to the case of nonflexible MOFs such as MOF-5 and ZIF-8. In addition, we show that flexible MOFs can display extremely large negative linear compressibility. These results uncover the microscopic roots of stimuli-induced structural transitions in flexible MOFs, by linking the local elastic behavior of the material and its multistability. © 2012 American Physical Society.
Reverdin G.,University Pierre and Marie Curie
Journal of Climate | Year: 2010
Surface temperature, salinity, and density are examined in the northeastern part of the North Atlantic subpolar gyre over the last 115 years of measurements. This region presents coherent variability in space but also between different seasons, with relatively small trends and large multidecadal variability. The most significant trend is a lowering in surface density. Multidecadal variability in T and S is large and is usually similar, with the largest difference between the two in the 1920s and a tendency of T to lead S. Multidecadal T and S are correlated with the winter North Atlantic Oscillation (NAO) index at 0 or 1-yr lag for T and 0 to 3-yr lag for S. This suggests a strong contribution of advection. The lag between T and S is also suggestive of a contribution of air-sea fluxes of heat or freshwater, but probably more so at high frequencies than at the multidecadal time scales. Salinity higher frequency is correlated with NAO at a 2-3-yr lag, whereas T higher frequency variability presents no correlation with NAO at any lag. This suggests different relations between seasonal NAO indices and air-sea heat fluxes patterns in this region before and after 1960; also the advective signal is more clearly identified in salinity in this region. © 2010 American Meteorological Society.
Basner-Tschakarjan E.,Childrens Hospital of Philadelphia |
Mingozzi F.,University Pierre and Marie Curie
Frontiers in Immunology | Year: 2014
Adeno-associated virus (AAV) vectors are one of the most efficient in vivo gene delivery platforms. Over the past decade, clinical trials of AAV vector-mediated gene transfer led to some of the most exciting results in the field of gene therapy and, recently, to the market approval of an AAV-based drug in Europe. With clinical development, however, it became obvious that the host immune system represents an important obstacle to successful gene transfer with AAV vectors. In this review article, we will discuss the issue of cytotoxic T cell responses directed against the AAV capsid encountered on human studies. While over the past several years the field has acquired a tremendous amount of information on the interactions of AAV vectors with the immune system, a lot of questions are still unanswered. Novel concepts are emerging, such as the relationship between the total capsid dose and the T cell-mediated clearance of transduced cells, the potential role of innate immunity in vector immunogenicity highlighted in preclinical studies, and the cross talk between regulatory and effector T cells in the determination of the outcome of gene transfer. There is still a lot to learn about immune responses in AAV gene transfer, for example, it is not well understood what are the determinants of the kinetics of activation of T cells in response to vector administration, why not all subjects develop detrimental T cell responses following gene transfer, and whether the intervention strategies currently in use to block T cell-mediated clearance of transduced cells will be safe and effective for all gene therapy indications. Results from novel preclinical models and clinical studies will help to address these points and to reach the important goal of developing safe and effective gene therapy protocols to treat human diseases. © 2014 Basner-Tschakarjan and Mingozzi.
Servois V.,University Pierre and Marie Curie
British Journal of Cancer | Year: 2016
Background:The aim of the study was to analyse efficacy, safety, and health-related quality of life (HRQoL) for sorafenib treatment in patients with metastatic uveal melanoma.Methods:A multicentre, single-arm phase II trial was conducted. The primary objective was to determine the non-progression rate (RECIST) at 24 weeks for patients receiving sorafenib at a dose of 800 mg per day. Secondary endpoints included progression-free survival (PFS), overall survival (OS), toxicity, and HRQoL.Results:Thirty-two patients were included. Ten patients showed non-progression at 24 weeks (31.2%) without objective tumour responses. The estimated 24-week PFS was 31.2% (95% CI: 14.8%–47.6%) and the estimated 24-week OS was 62.5% (95% CI: 45.4%–79.6%). Ten patients (34.3%) had at least one grade 3 or 4 adverse reaction and 12 patients (41.4%) required dose modifications due to toxicity. At 24 weeks, no patient had an improvement in global HRQoL and 87.5% experienced a permanent increase in physical fatigue.Conclusions:Sorafenib demonstrated non-progression at 24 weeks in 31.2% of patients. However, 41.4% of patients required dose modifications due to toxicity and no improvement in HRQoL was demonstrated.British Journal of Cancer advance online publication, 2 June 2016; doi:10.1038/bjc.2016.119 www.bjcancer.com. © 2016 Cancer Research UK
MacHet B.,University Pierre and Marie Curie |
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011
We obtain the following analytical formula which describes the dependence of the electric potential of a pointlike charge on the distance away from it in the direction of an external magnetic field B: Φ(z)=e/|z|[1-exp(- √6me2|z|)+exp(-√(2/π)e3B+6me2|z|)]. The deviation from Coulomb's law becomes essential for B>3πBcr/α=3πme2/ e36×1016G. In such superstrong fields, electrons are ultrarelativistic except those which occupy the lowest Landau level (LLL) and which have the energy ε02=me2+pz2. The energy spectrum on which LLL splits in the presence of the atomic nucleus is found analytically. For B>3πB cr/α it differs substantially from the one obtained without accounting for the modification of the atomic potential. © 2011 American Physical Society.
Chassefiere E.,University Paris - Sud |
Chassefiere E.,French National Center for Scientific Research |
Leblanc F.,University Pierre and Marie Curie
Earth and Planetary Science Letters | Year: 2011
It has been suggested that Mars' atmospheric CH4 could be produced by crustal hydrothermal systems. The two most plausible mechanisms proposed so far, not exclusive from each other, are homogeneous formation by fluid-rock interaction during magmatic events and serpentinization of ultramafic rocks. The first goal of the present paper is to provide an upper limit on the release rate of serpentinization-derived CH4. Due to the release of numerous H2 molecules together with one CH4 molecule, followed by thermal escape of all released H atoms to space and subsequent H isotopic fractionation, even a relatively modest serpentinization-derived CH4 release acting over geological time scales may result in a significant enrichment of D wrt H in Mars' cryo-hydrosphere, including atmosphere, polar caps and subsurface reservoirs. By assuming that the CH4 release rate has been proportional to the volcanic extrusion rate during the last 4billion years, we calculate the present D/H ratio resulting from the crustal oxidation due to serpentinization, including the additional effect of sulfur oxidation. We show that this rate doesn't exceed 20% (within a factor of 2) of the estimated present value of the CH4 release rate. If not, the present D/H ratio on Mars would be larger than observed (~5 SMOW). This result suggests that, either the production of CH4 is sporadic with a present release rate larger than the average rate, or there are other significant sources of CH4 like homogeneous formation from mantle carbon degassing or bacterial activity. Second, assuming further that most of the H isotopic fractionation observed today is due to serpentinization, we show that a ~400m thick global equivalent layer of water may have been stored in serpentine since the late Noachian. This result doesn't depend on the chemical form of the released hydrogen (H2 or CH4). Such a quantity is generally considered as the amount required for explaining the formation of valley networks on Mars. Serpentinization therefore appears as a potentially efficient sink of water on Mars, much more efficient than O escape' for having removed large amounts of water from the hydrosphere. © 2011 Elsevier B.V.
Storek J.,University of Calgary |
Mohty M.,University Pierre and Marie Curie |
Boelens J.J.,University Utrecht
Biology of Blood and Marrow Transplantation | Year: 2015
Anti-T cell globulin (ATG) is polyclonal IgG from rabbits immunized with human thymocytes or a human T cell line. Prophylaxis using ATG infused with conditioning for adult marrow or blood stem cell transplantation reduces both acute and chronic graft-versus-host disease (GVHD). However, ATG is not or minimally efficacious in steroid refractory GVHD treatment. Regarding preemptive therapy, ATG is promising; however, further work is needed on establishing adequate biomarkers to be used as triggers for preemptive therapy before it can be used routinely. Relapse is not increased by ATG, except possibly in the setting of reduced-intensity conditioning. Infections are probably increased when using high but not low-dose ATG, except for Epstein-Barr virus-driven post-transplantation lymphoproliferative disorder, which may be increased even with low-dose ATG. Survival is not improved with ATG; however, survival free of immunosuppressive therapy is improved. Pharmacokinetics of ATG are highly variable, resulting in highly variable areas under the time-concentration curves. Optimized dosing of ATG might improve transplantation outcomes. In conclusion, ATG reduces GVHD and, thus, may improve quality of life, without compromising survival. © 2015 American Society for Blood and Marrow Transplantation.
Joanny J.-F.,University Pierre and Marie Curie |
Ramaswamy S.,Indian Institute of Science
Journal of Fluid Mechanics | Year: 2012
We study theoretically the hydrodynamics of a fluid drop containing oriented filaments endowed with active contractile or extensile stresses and placed on a solid surface. The active stresses alter qualitatively the wetting properties of the drop, leading to new spreading laws and novel static drop shapes. Candidate systems for testing our predictions include cytoskeletal extracts with motors and ATP, suspensions of bacteria or pulsatile cells, or fluids laden with artificial self-propelled colloids. © 2011 Cambridge University Press.
Marsh D.J.E.,Perimeter Institute |
Silk J.,University Pierre and Marie Curie |
Silk J.,Johns Hopkins University |
Silk J.,University of Oxford
Monthly Notices of the Royal Astronomical Society | Year: 2014
There are several issues to do with dwarf galaxy predictions in the standard δ cold dark matter (δCDM) cosmology that have suscitated much recent debate about the possible modification of the nature of dark matter as providing a solution. We explore a novel solution involving ultralight axions that can potentially resolve the missing satellites problem, the cusp-core problem and the 'too big to fail' problem. We discuss approximations to non-linear structure formation in dark matter models containing a component of ultralight axions across four orders of magnitude in mass, 10-24 < ma < 10-20 eV, a range too heavy to be well constrained by linear cosmological probes such as the cosmic microwave background and matter power spectrum, and too light/non-interacting for other astrophysical or terrestrial axion searches. We find that an axion of mass ma ~ 10-21 eV contributing approximately 85 per cent of the total dark matter can introduce a significant kpc scale core in a typical Milky Way satellite galaxy in sharp contrast to a thermal relic with a transfer function cut off at the same scale, while still allowing such galaxies to form in significant number. Therefore, ultralight axions do not suffer from the Catch 22 that applies to using a warm dark matter as a solution to the small-scale problems of CDM. Our model simultaneously allows formation of enough highredshift galaxies to allow reconciliation with observational constraints, and also reduces the maximum circular velocities of massive dwarfs so that baryonic feedback may more plausibly resolve the predicted overproduction of massive Milky Way Galaxy dwarf satellites. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.
In vitro fragmentation efficiency of holmium: Yttrium-aluminum-garnet (YAG) laser lithotripsy - A comprehensive study encompassing different frequencies, pulse energies, total power levels and laser fibre diameters
Kronenberg P.,Hospital Prof Doutor Fernando Fonseca |
Traxer O.,University Pierre and Marie Curie
BJU International | Year: 2014
Objective To assess the fragmentation (ablation) efficiency of laser lithotripsy along a wide range of pulse energies, frequencies, power settings and different laser fibres, in particular to compare high- with low-frequency lithotripsy using a dynamic and innovative testing procedure free from any human interaction bias. Materials and Methods An automated laser fragmentation testing system was developed. The unmoving laser fibres fired at the surface of an artificial stone while the stone was moved past at a constant velocity, thus creating a fissure. The lithotripter settings were 0.2-1.2 J pulse energies, 5-40 Hz frequencies, 4-20 W power levels, and 200 and 550 μm core laser fibres. Fissure width, depth, and volume were analysed and comparisons between laser settings, fibres and ablation rates were made. Results Low frequency-high pulse energy (LoFr-HiPE) settings were (up to six times) more ablative than high frequency-low pulse energy (HiFr-LoPE) at the same power levels (P < 0.001), as they produced deeper (P < 0.01) and wider (P < 0.001) fissures. There were linear correlations between pulse energy and fragmentation volume, fissure width, and fissure depth (all P < 0.001). Total power did not correlate with fragmentation measurements. Laser fibre diameter did not affect fragmentation volume (P = 0.81), except at very low pulse energies (0.2 J), where the large fibre was less efficient (P = 0.015). Conclusions At the same total power level, LoFr-HiPE lithotripsy was most efficient. Pulse energy was the key variable that drove fragmentation efficiency. Attention must be paid to prevent the formation of time-consuming bulky debris and adapt the lithotripter settings to one's needs. As fibre diameter did not affect fragmentation efficiency, small fibres are preferable due to better scope irrigation and manoeuvrability. © 2013 The Authors. BJU International © 2013 BJU International.
Glukhova M.A.,University of Manchester |
Glukhova M.A.,University Pierre and Marie Curie |
Streuli C.H.,University of Manchester
Current Opinion in Cell Biology | Year: 2013
This article explores new ideas about how the ECM-integrin axis controls normal and malignant breast biology. We discuss the role of integrins in mammary stem cells, and how cell-matrix interactions regulate ductal and alveolar development and function. We also examine the contribution of integrins to tissue disorganisation and metastasis, and how an altered stromal and ECM tumour microenvironment affects the cancer cell niche both within primary tumours and at distant sites. Finally, we mention novel strategies for integrin-directed breast cancer treatment. © 2013 The Authors.
Le Treut H.,University Pierre and Marie Curie
Surveys in Geophysics | Year: 2012
The past record of global earth surface temperatures is unable to offer quantitative evidence about the amplitude of climate sensitivity, due to the competing effects of long-lived greenhouse gases and short-lived aerosols. This factor constitutes one of the reasons why uncertainties about climate sensitivity have remained almost unchanged for more than 30 years, and it is also limiting our current capacity to propose reliable climate projections for the coming century. This paper offers a short review of the studies that have dealt with this issue. A number of approaches aim at a process-oriented diagnostic of current models. These studies are in constant progress since the launch of remote-sensing instruments, such as those from the A-train satellite constellation. Past climate fluctuations may also offer some limited possibilities to discriminate the effects of greenhouse gases and aerosols. There is therefore a real hope that climate projections may eventually become more accurate, which would be extremely useful in monitoring global warming during the next decades. © 2012 Springer Science+Business Media B.V.
Meister P.,University of Bern |
Taddei A.,French National Center for Scientific Research |
Taddei A.,University Pierre and Marie Curie
Current Opinion in Genetics and Development | Year: 2013
In eukaryotes, the genetic material is stored in the nucleus, which is enclosed in a double lipid bilayer, the nuclear envelope (NE). It protects the genome from physical stress and separates it from the rest of the cell. On top of this physical function, growing evidence shows that the nuclear periphery contributes to the 3D organization of the genome. In turn, tridimensional organization of chromatin in the nuclear space influences genome expression. Here we review recent findings on the function of this physical barrier in gene repression and latest models on how silent subnuclear compartments at the NE are built in yeast as well as in the nematode C. elegans and mammalian cells; trying to draw parallels between the three systems. © 2013 Elsevier Ltd.
Westerhold T.,University of Bremen |
Rohl U.,University of Bremen |
Laskar J.,University Pierre and Marie Curie
Geochemistry, Geophysics, Geosystems | Year: 2012
Timing is crucial to understanding the causes and consequences of events in Earth history. The calibration of geological time relies heavily on the accuracy of radioisotopic and astronomical dating. Uncertainties in the computations of Earth's orbital parameters and in radioisotopic dating have hampered the construction of a reliable astronomically calibrated time scale beyond 40 Ma. Attempts to construct a robust astronomically tuned time scale for the early Paleogene by integrating radioisotopic and astronomical dating are only partially consistent. Here, using the new La2010 and La2011 orbital solutions, we present the first accurate astronomically calibrated time scale for the early Paleogene (47-65 Ma) uniquely based on astronomical tuning and thus independent of the radioisotopic determination of the Fish Canyon standard. Comparison with geological data confirms the stability of the new La2011 solution back to ∼54 Ma. Subsequent anchoring of floating chronologies to the La2011 solution using the very long eccentricity nodes provides an absolute age of 55.530 0.05 Ma for the onset of the Paleocene/Eocene Thermal Maximum (PETM), 54.850 0.05 Ma for the early Eocene ash -17, and 65.250 0.06 Ma for the K/Pg boundary. The new astrochronology presented here indicates that the intercalibration and synchronization of U/Pb and 40Ar/ 39Ar radioisotopic geochronology is much more challenging than previously thought. ©2012. American Geophysical Union. All Rights Reserved. 1 of 19.
Roehner B.M.,University Pierre and Marie Curie
Physica A: Statistical Mechanics and its Applications | Year: 2015
The monthly pattern of suicides has remained a puzzle ever since it was discovered in the second half of the 19th century. In this paper we intend to "explain" not the pattern itself but rather its changes across countries and in the course of time. First, we show that the fairly common idea according to which this pattern is decaying in "modern" societies is not altogether true. For instance, around 2000, in well urbanized countries like South Korea or Spain this pattern was still as strong as it was in France (and other European countries) in the late 19th century. The method that we use in order to make some progress in our understanding is the time-honored Cartesian approach of breaking up the problem under consideration "into as many parts as might be necessary to solve it". More specifically, we try two separations of monthly suicides into simpler components: (i) according to suicide methods and (ii) according to age-groups. These separations rely on the introduction of what we call "elementary monthly profiles". The first separation points out the key-role of hanging and drowning. The second shows the crucial role of the 15-20 and 65+ age-groups. Then, we present a number of cases in which age-group decomposition provides adequate predictions. It turns out that the cases in which the predictions do not work are newly urbanized countries. The discrepancies may be due to a memory effect which induces a time-lag extending over one or two generations. Finally, in the light of the new results presented in the present paper, we re-examine the theory proposed by Emile Durkheim. © 2015 Elsevier B.V. All rights reserved.
Boucher O.,University Pierre and Marie Curie
Earth System Dynamics | Year: 2012
There is a controversy on the role methane (and other short-lived species) should play in climate mitigation policies, and there is no consensus on what an optimal methane CO 2-equivalence should be.We revisit this question by discussing some aspects of physically-based (i.e. globalwarming potential or GWP and global temperature change potential or GTP) and socio-economically-based climate metrics. To this effect we use a simplified global damage potential (GDP) that was introduced by earlier authors and investigate the uncertainties in the methane CO 2-equivalence that arise from physical and socio-economic factors. The median value of the methane GDP comes out very close to the widely used methane 100-yr GWP because of various compensating effects. However, there is a large spread in possible methane CO 2-equivalences from this metric (1-99% interval: 10.0-42.5; 5-95%interval: 12.5-38.0) that is essentially due to the choice in some socio-economic parameters (i.e. the damage cost function and the discount rate). The main factor differentiating the methane 100-yr GTP from the methane 100-yr GWP and the GDP is the fact that the former metric is an end-point metric, whereas the latter are cumulative metrics. There is some rationale for an increase in the methane CO 2- equivalence in the future as global warming unfolds, as implied by a convex damage function in the case of the GDP metric. We also show that a methane CO 2-equivalence based on a pulse emission is sufficient to inform multi-year climate policies and emissions reductions, as long as there is enough visibility on CO 2 prices and CO 2-equivalences for the stakeholders. © Author(s) 2012.
Jiang R.,CNRS Laboratory of Design and Application of Bioactive Molecules |
Taly A.,University Pierre and Marie Curie |
Grutter T.,CNRS Laboratory of Design and Application of Bioactive Molecules
Trends in Biochemical Sciences | Year: 2013
P2X receptors are nonselective cation channels gated by extracellular ATP. They represent new therapeutic targets, and they form channels with a unique trimeric architecture. In 2009, the first crystal structure of a P2X receptor was reported, in which the receptor was in an ATP-free, closed channel state. However, our view recently changed when a second crystal structure was reported, in which a P2X receptor was bound to ATP and resolved in an open channel conformation. This remarkable structure not only confirms many key experimental data, including the recent mechanisms of ATP binding and ion permeation, but also reveals unanticipated mechanisms. Certainly, this new information will accelerate our understanding of P2X receptor function and pharmacology at the atomic level. © 2012 Elsevier Ltd.
Aires F.,University Pierre and Marie Curie |
Aires F.,French National Center for Scientific Research
Journal of Geophysical Research: Atmospheres | Year: 2011
A synergetic scheme refers to an algorithm that simultaneously or hierarchically uses the observations of two or more spectral ranges in order to obtain a more accurate retrieval than the independent retrievals put together. This study is composed of two companion papers; this first part introduces some theoretical considerations. The goal of this study is, first, to identify the various forms of synergy for remote sensing applications. Simple linear models are used to introduce concepts such as additive, unmixing, indirect, or denoising synergies. The second objective of this paper is to develop a methodology to measure, in real-world applications, these different synergies. For this purpose, some experiments are conducted using the classical information content analysis which is often used in the context of assimilation or to design new instruments. This technique is tested on a real-world application where the microwave and infrared observations from the Atmospheric Microwave Sounding Unit-A, Microwave Humidity Sounder, and Improved Atmospheric Sounding in the Infrared instruments are used to retrieve the atmospheric profiles of temperature and water vapor over ocean, under clear-sky conditions. This approach will show its limitation to measure synergy and stress the need for other tools. In the companion paper, statistical retrieval schemes will show their potential to measure and exploit existing synergies, for the same application. Copyright 2011 by the American Geophysical Union.
Peeters C.,University Pierre and Marie Curie
Myrmecological News | Year: 2012
Flight is a one-off event in ants, hence after mating, the wing muscles of winged queens can function as protein reserves during independent colony foundation (ICF). Another strategy occurring in many unrelated lineages is dependent colony foundation (DCF). DCF does not require queens with expensive wing muscles because dispersal is on foot, and a found-ress relies on nestmate workers to feed her first brood of workers. The shift to DCF seems the reason why wingless reproductives (ergatoid queens, short-winged queens, and gamergates) evolved independently in more than 50 genera belonging to 16 subfamilies. In various species they occur together with winged queens (in the same or different popu-lations), in other species winged queens were replaced completely. Because wingless reproductives are the product of convergence, there is tremendous heterogeneity in morphological characteristics as well as selective contexts. These novel reproductive phenotypes cannot function without nestmate workers (foundresses forage in only few species), hence addi-tional investment in workers is needed.
Stankovic Stojanovic K.,University Pierre and Marie Curie
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association | Year: 2012
Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder, for which systemic AA amyloidosis is the major complication revealed most of the time by renal abnormalities. Current treatment is daily colchicine that prevents both recurrent inflammatory attacks and amyloidosis deposition in most patients. However, some patients still develop amyloidosis and renal failure. Functional studies suggest that interleukin (IL)-1 is implicated in the inflammatory reaction in FMF and therefore, IL-1 inhibitors could be a new approach to treat FMF. The aim of this series study was to evaluate anakinra in patients with FMF complicated with amyloidosis and renal failure. We studied a series of adult patients with FMF complicated with amyloidosis and treated with anakinra in one reference centre were reviewed. A search for published patients with FMF associated amyloidosis treated with anakinra was performed by screening PubMed. We report four cases of patients with FMF-associated amyloidosis treated with anakinra and discuss the clinical pertinence of its use in these particular clinical settings. Anakinra has a strong effect on both inflammatory attacks and general status in patients with FMF-associated amyloidosis. It may contribute to changing the prognosis of these patients. Long-term studies are needed to appreciate the effect of anakinra or other IL-1 inhibitors on the natural history of amyloidosis in these patients.
Habert G.,University Paris Est Creteil |
D'Espinose De Lacaillerie J.B.,University Pierre and Marie Curie |
Roussel N.,University Paris Est Creteil
Journal of Cleaner Production | Year: 2011
In this study we carry out a detailed environmental evaluation of geopolymer concrete production using the Life Cycle Assessment methodology. The literature shows that the production of most standard types of geopolymer concrete has a slightly lower impact on global warming than standard Ordinary Portland Cement (OPC) concrete. Whilst our results confirm this they also show that the production of geopolymer concrete has a higher environmental impact regarding other impact categories than global warming. This is due to the heavy effects of the production of the sodium silicate solution. Geopolymer concrete made from fly ashes or granulated blast furnace slags based require less of the sodium silicate solution in order to be activated. They therefore have a lower environmental impact than geopolymer concrete made from pure metakaolin. However, when the production of fly ashes and granulated blast furnace slags is taken into account during the life cycle assessment (using either an economic or a mass allocation procedure), it appears that geopolymer concrete has a similar impact on global warming than standard concrete. This study highlights that future research and development in the field of geopolymer concrete technology should focus on two potential solutions. First of all the use of industrial waste that is not recyclable within other industries and secondly on the production of geopolymer concrete using a mix of blast furnace slag and activated clays. Furthermore geopolymer concrete production would gain from using waste material with a suitable Si/Al molar ratio in order to minimise the amount of sodium silicate solution used. Finally, by taking into account mix-design technology, which has already been developed for OPC concrete, the amount of binder required to produce a geopolymer concrete could be reduced. © 2011 Elsevier Ltd. All rights reserved.
Drewnowski A.,University of Washington |
Drewnowski A.,University Pierre and Marie Curie |
Fulgoni III V.L.,Nutrition Impact LLC
American Journal of Clinical Nutrition | Year: 2014
Nutrient profiling is the technique of rating or classifying foods on the basis of their nutritional value. Foods that supply relatively more nutrients than calories are defined as nutrient dense. Nutrient profile models calculate the content of key nutrients per 100 g, 100 kcal, or per serving size of food. For maximum effectiveness, nutrient profile models need to be transparent, based on publicly accessible nutrient composition data, and validated against independent measures of a healthy diet. These rigorous scientific standards were applied to the development of the Nutrient-Rich Foods (NRF) family of nutrient profile models. First, the NRF models included nutrients to encourage as well as nutrients to limit. Second, NRF model performance was repeatedly tested against the Healthy Eating Index (HEI), an independent measure of a healthy diet. HEI values were calculated for participants in the 1999-2002 NHANES. Models based on 100 kcal and serving sizes performed better than those based on 100 g. Formulas based on sums and means performed better than those based on ratios. The final NRF9.3 index was based on 9 beneficial nutrients (protein; fiber; vitamins A, C, and E; calcium; iron; potassium; and magnesium) and on 3 nutrients to limit (saturated fat, added sugar, and sodium). Higher NRF9.3 scores were associated with lower energy density and more nutrient-rich diets. The nutrient density of foods, paired with a comprehensive program of consumer education, can become the foundation of dietary recommendations and guidelines. © 2014 American Society for Nutrition.
Cocco S.,CNRS ENS Statistical Physics Laboratory |
Monasson R.,CNRS Physics Laboratory |
Weigt M.,University Pierre and Marie Curie
PLoS Computational Biology | Year: 2013
Various approaches have explored the covariation of residues in multiple-sequence alignments of homologous proteins to extract functional and structural information. Among those are principal component analysis (PCA), which identifies the most correlated groups of residues, and direct coupling analysis (DCA), a global inference method based on the maximum entropy principle, which aims at predicting residue-residue contacts. In this paper, inspired by the statistical physics of disordered systems, we introduce the Hopfield-Potts model to naturally interpolate between these two approaches. The Hopfield-Potts model allows us to identify relevant 'patterns' of residues from the knowledge of the eigenmodes and eigenvalues of the residue-residue correlation matrix. We show how the computation of such statistical patterns makes it possible to accurately predict residue-residue contacts with a much smaller number of parameters than DCA. This dimensional reduction allows us to avoid overfitting and to extract contact information from multiple-sequence alignments of reduced size. In addition, we show that low-eigenvalue correlation modes, discarded by PCA, are important to recover structural information: the corresponding patterns are highly localized, that is, they are concentrated in few sites, which we find to be in close contact in the three-dimensional protein fold. © 2013 Cocco et al.
Saint-Raymond L.,University Pierre and Marie Curie
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2013
Boltzmann brought a fundamental contribution to the understanding of the notion of entropy, by giving a microscopic formulation of the second principle of thermodynamics. His ingenious idea, motivated by the works of his contemporaries on the atomic nature of matter, consists of describing gases as huge systems of identical and indistinguishable elementary particles. The state of a gas can therefore be described in a statistical way. The evolution, which introduces couplings, loses part of the information, which is expressed by the decay of the so-called mathematical entropy (the opposite of physical entropy!). © 2013 The Author(s) Published by the Royal Society. All rights reserved.
Pitaval A.,Institute Of Recherche En Science Et Technologies Pour Le Vivant |
Tseng Q.,French National Institute for Agricultural Research |
Bornens M.,University Pierre and Marie Curie |
Thery M.,French National Institute for Agricultural Research
Journal of Cell Biology | Year: 2010
In most lineages, cell cycle exit is correlated with the growth of a primary cilium. We analyzed cell cycle exit and ciliogenesis in human retinal cells and found that, contrary to the classical view, not all cells exiting the cell division cycle generate a primary cilium. Using adhesive micropatterns to control individual cell spreading, we demonstrate that cell spatial confinement is a major regulator of ciliogenesis. When spatially confined, cells assemble a contractile actin network along their ventral surface and a protrusive network along their dorsal surface. The nucleus-centrosome axis in confined cells is oriented toward the dorsal surface where the primary cilium is formed. In contrast, highly spread cells assemble mostly contractile actin bundles. The nucleus-centrosome axis of spread cells is oriented toward the ventral surface, where contractility prevented primary cilium growth. These results indicate that cell geometrical confinement affects cell polarity via the modulation of actin network architecture and thereby regulates basal body positioning and primary cilium growth. © 2010 Pitaval et al.
Shirley C.,University Pierre and Marie Curie
Journal of Statistical Physics | Year: 2015
The purpose of the present work is to establish decorrelation estimates for some random discrete Schrödinger operator in dimension one. We prove that the Minami estimates are consequences of the Wegner estimates and localization. We also prove decorrelation estimates at distinct energies for the random hopping model and Schrödinger operators with alloy-type potentials. These results are used to give a description of the spectral statistics. © 2014, Springer Science+Business Media New York.
Fechete I.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health |
Wang Y.,Xiamen University |
Vedrine J.C.,University Pierre and Marie Curie
Catalysis Today | Year: 2012
This review highlights key catalytic discoveries and the main industrial catalytic processes over the last 300 years that involved commodities, fine chemicals, petrochemicals, petroleum transformation for fuels and energy supply, emission control, and so forth. In the past, discoveries have often followed events such as wars or embargos, whereas the current driving forces of studies, researches and then discoveries aim at a better understanding of catalytic processes, at reducing the costs of raw materials and processes, at developing new catalytic materials and at addressing environmental issues. This review focuses on the history of many catalytic industrial processes, environmental issues, catalytic materials, especially their expected catalytic properties, on catalyst characterisation by physical methods and development of in situ conditions, i.e., characterisation under actual working conditions with reactants and products analyzed on-line. Emphasis is also placed on high selectivity in catalytic reactions and the major challenges for the future, such as environmental issues, energy supply, pollution control for vehicles and industrial plants, air/VOCs/water purification, hydrogen sources and carbon dioxide storage/up grading, transformation of biomass as a promising source of raw materials, and catalytic water splitting perspectives. This review is a survey of heterogeneous catalysis and is not comprehensive but leads to the conclusion that, although many catalysts and catalytic processes have already been discovered and developed over the past century, many opportunities nevertheless exist for new developments, new processes and new catalytic materials. It follows that substantial challenges exist for the younger generation of researchers and engineers, as emphasized at the end of the manuscript. © 2012 Elsevier B.V. All rights reserved.
Colomban P.,University Pierre and Marie Curie
Journal of Raman Spectroscopy | Year: 2011
A rare 18th century wallpaper depicting a basket of flowers has been recently discovered in the building where Buffon, the famous French Naturalist, had established his Library and written a large part of its 'Histoire Naturelle'. The wallpaper fragments were analysed and some pigments identified: gypsum, calcite, carbon black, vermilion and lapis lazuli; a blue/green organic compound was seemingly used to dye the paper. Copyright © 2010 John Wiley & Sons, Ltd.
Pileni M.P.,University Pierre and Marie Curie
Journal of Materials Chemistry | Year: 2011
Nanocrystals are able to self-assemble in hexagonal networks (2D) and in supracrystals (3D). Here it is shown that the interparticle distance is tuned by the presence of water molecules adsorbed at the nanocrystal interface and on the alkyl chains used as coating agents. By using an intrinsic property due to the nanocrystal ordering, a new, but destructive, method is proposed to detect defects on a large monolayer scale. The supracrystal growth mechanism changes with the nanocrystal size from a heterogeneous (layer-by-layer) to a homogeneous (growth in solution) process. Co supracrystals are highly stable after annealing at 350 °C with an improvement in the nanocrystal ordering, i.e., in the supracrystallinity. With Ag supracrystals it was possible, from the same batch of 5 nm Ag nanocrystals, to control the supracrystallinity with phase transitions of hcp to fcc and amorphous solids to hcp and bcc. Finally a tentative analogy between atoms and nanocrystals is proposed in the crystal growth process. These data open a new research area with a large potential for discovering new chemical and physical properties. © 2011 The Royal Society of Chemistry.
Grosso D.,University Pierre and Marie Curie
Journal of Materials Chemistry | Year: 2011
Dip-coating is an ideal method to prepare thin layers from chemical solutions since it is a low-cost and waste-free process that is easy to scale up and offers a good control on thickness. For such reasons, it is becoming more and more popular not only in research and development laboratories, but also in industrial production, as testified by the increasing number of annual publications (9, 180, and 480 articles in 1990, 2000, and 2010, respectively). Even so, the full potential of dip-coating has not yet been fully explored and exploited. This article highlights the recent progresses made by tuning the processing conditions beyond conventional ranges to prepare more and more complex and controlled nanostructured layers. Especially, we will see how one can take advantage of an accurate tuning of the withdrawal speed and of the atmosphere to control the nanostructuration originating from evaporation-induced-self-assembly (EISA), together with the final thickness from a few nm up to 1 μm from the same initial solution. A new regime of deposition, involving capillary induced convective coating that is highly suitable for the deposition from aqueous and/or highly diluted solutions, will be described. Finally, it will be demonstrated that dip-coating is also a well suited method to impregnate porosity, to make nanocomposites, or to perform nanocasting. The present discussion is illustrated with systems of interests in domains such as optics, energies, nanoelectronics, nanofluidics, etc. © 2011 The Royal Society of Chemistry.
Audoly B.,University Pierre and Marie Curie
Skin Research and Technology | Year: 2013
Background/Purpose: Skin mechanical properties are globally well described. The aim of this paper is to evaluate, by means of a numerical model, the influence of Stratum Corneum (SC) on skin folding resulting from an in-plane compression. Methods: A computational skin model was developed where skin is divided into three layers (SC, epidermis and upper dermis, and deep dermis) of different thicknesses and elastic moduli. Skin surface deformation, consecutive to the application of a given surface compression, was computed by minimizing the mechanical energy of the multi-layered tissue. Influence of SC thickness and elastic modulus on skin buckling is presented. Results: Varying both SC thickness and elastic modulus has a marked influence on both wavelength and amplitude of the skin's surface folds. These two parameters display a logarithmic variation versus SC elastic modulus. Conclusion: Although representing about one hundredth of the total skin thickness, SC has a marked influence on the skin mechanical properties. © 2012 John Wiley & Sons A/S.
Terray P.,University Pierre and Marie Curie
Climate Dynamics | Year: 2011
The main goal of this paper is to shed additional light on the reciprocal dynamical linkages between mid-latitude Southern Hemisphere climate and the El Niño-Southern Oscillation (ENSO) signal. While our analysis confirms that ENSO is a dominant source of interannual variability in the Southern Hemisphere, it is also suggested here that subtropical dipole variability in both the Southern Indian and Atlantic Oceans triggered by Southern Hemisphere mid-latitude variability may also provide a controlling influence on ENSO in the equatorial Pacific. This subtropical forcing operates through various coupled air-sea feedbacks involving the propagation of subtropical sea surface temperature (SST) anomalies into the deep tropics of the Atlantic and Indian Oceans from boreal winter to boreal spring and a subsequent dynamical atmospheric response to these SST anomalies linking the three tropical basins at the beginning of the boreal spring. This atmospheric response is characterized by a significant weakening of the equatorial Atlantic and Indian Inter-Tropical Convergence Zone (ITCZ). This weakened ITCZ forces an equatorial "cold Kelvin wave" response in the middle to upper troposphere that extends eastward from the heat sink regions into the western Pacific. By modulating the vertical temperature gradient and the stability of the atmosphere over the equatorial western Pacific Ocean, this Kelvin wave response promotes persistent zonal wind and convective anomalies over the western equatorial Pacific, which may trigger El Niño onset at the end of the boreal winter. These different processes explain why South Atlantic and Indian subtropical dipole time series indices are highly significant precursors of the Niño34 SST index several months in advance before the El Niño onset in the equatorial Pacific. This study illustrates that the atmospheric internal variability in the mid-latitudes of the Southern Hemisphere may significantly influence ENSO variability. However, this surprising relationship is observed only during recent decades, after the so-called 1976/1977 climate regime shift, suggesting a possible linkage with global warming or decadal fluctuations of the climate system. © 2010 Springer-Verlag.
Lafuente-Lafuente C.,University Pierre and Marie Curie
The Cochrane database of systematic reviews | Year: 2013
Active compression-decompression cardiopulmonary resuscitation (ACDR CPR) uses a hand-held suction device, applied mid-sternum, to compress the chest then actively decompress the chest after each compression. Randomised controlled trials testing this device have shown discordant results. To determine the effect of active chest compression-decompression CPR compared to standard chest compression CPR on mortality and neurological function in adults with cardiac arrest treated either in-hospital or out-of-hospital. We updated the searches of CENTRAL in The Cochrane Library (Issue 12 of 12, 2012), MEDLINE (OVID, 1946 to January week 1 2013), and EMBASE (OVID, 1980 to week 1 2013) on 14 January 2013. We checked the reference list of retrieved articles, contacted experts in the field, and searched ClinicalTrials.gov. All randomised or quasi-randomised studies comparing active compression-decompression with standard manual chest compression in adults with a cardiac arrest who received cardiopulmonary resuscitation by a trained medical or paramedical team. We independently extracted data on an intention-to-treat basis. When needed, we contacted the authors of the primary studies. If appropriate, we cumulated studies and pooled relative risk (RR) estimates. We predefined subgroup analyses according to setting (out-of-hospital or in-hospital) and attending team composition (with physician or paramedic only). In this update, 27 new related publications were found, but they did not all fulfil inclusion criteria or concerned participants already reported in previous publications. In the end, we included 10 trials in this review: Eight were in out-of-hospital settings; one was set in-hospital only; and one had both in-hospital and out-of-hospital components. Allocation concealment was adequate in four studies. The two in-hospital studies were different in quality and size (773 and 53 participants). Both found no differences between ACDR CPR and STR in any outcome.Out-of-hospital trials cumulated 4162 participants. There were no differences between ACDR CPR and STR for mortality either immediately (RR 0.98, 95% confidence interval (CI) 0.94 to 1.03) or at hospital discharge (RR 0.99, 95% CI 0.98 to 1.01). The pooled RR of neurological impairment of any severity was 1.71 (95% CI 0.90 to 3.25), with a non-significant trend to more frequent severe neurological damage in survivors of ACDR CPR (RR 3.11, 95% CI 0.98 to 9.83). However, assessment of neurological outcome was limited, and few participants had neurological damage.There was no difference between ACDR CPR and STR with regard to complications such as rib or sternal fractures, pneumothorax, or haemothorax (RR 1.09, 95% CI 0.86 to 1.38). Skin trauma and ecchymosis were more frequent with ACDR CPR. Active chest compression-decompression in people with cardiac arrest is not associated with any clear benefit.
Pironneau O.,University Pierre and Marie Curie
Journal of Computational Finance | Year: 2012
It was shown in a 2011 paper by R. Cont, N. Lantos and O. Pironneau that the computational time of the Black–Scholes partial differential equation can be dramatically reduced by writing the solution on a small set of basis functions. We show that this is, in fact, a proper orthogonal decomposition method, and, when using some other variables, it is a spectral method. This allows us to find a good preconditioning matrix with which to minimize the ill-conditioned linear system, and even to obtain explicit solutions. © 2012, Incisive Media Ltd. All Rights Reserved.
Crouzeix M.,University of Rennes 1 |
Combescot M.,University Pierre and Marie Curie
Physical Review Letters | Year: 2011
This Letter provides the solution to a yet unsolved basic problem of solid state physics: the ground state energy of an arbitrary number of Cooper pairs interacting via the Bardeen-Cooper-Schrieffer potential. We here break a 50 yr old math problem by analytically solving Richardson-Gaudin equations which give the exact energy of these N pairs via N parameters coupled through N nonlinear equations. Our result fully supports the standard BCS result obtained for a pair number equal to half the number of states feeling the potential. More importantly, it shows that the interaction part of the N-pair energy depends on N as N(N-1) only from N=1 to the dense regime, a result which evidences that Cooper pairs interact via Pauli blocking only. © 2011 American Physical Society.
Suc J.-P.,University Pierre and Marie Curie |
Fauquette S.,Montpellier University
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2012
Northern Hemisphere vegetation is generally zoned as a consequence of latitudinal and altitudinal gradients. Temperature reconstruction from three successive pollen floral assemblages (of Tortonian, Messinian and Zanclean age) from the eastern Pyrenees has been used to estimate the altitudinal evolution of the uplifted Cerdanya Basin and its surrounding massifs. A new method has been developed for the uplifted basins, which completes that already applied to pollen floras from coastal marine deposits close to mountains. In contrast to previous hypotheses, it seems that the eastern Pyrenees occurred at a lower altitude in the Late Miocene before continuous uplift began 10. Ma ago. The rate of this uplift ranged between 0.06 and 0.12. mm/yr. © 2012 Elsevier B.V.
Gocho K.,University Pierre and Marie Curie
Investigative ophthalmology & visual science | Year: 2013
To report the findings of en face adaptive optics (AO) near infrared (NIR) reflectance fundus flood imaging in eyes with geographic atrophy (GA). Observational clinical study of AO NIR fundus imaging was performed in 12 eyes of nine patients with GA, and in seven controls using a flood illumination camera operating at 840 nm, in addition to routine clinical examination. To document short term and midterm changes, AO imaging sessions were repeated in four patients (mean interval between sessions 21 days; median follow up 6 months). As compared with scanning laser ophthalmoscope imaging, AO NIR imaging improved the resolution of the changes affecting the RPE. Multiple hyporeflective clumps were seen within and around GA areas. Time-lapse imaging revealed micrometric-scale details of the emergence and progression of areas of atrophy as well as the complex kinetics of some hyporeflective clumps. Such dynamic changes were observed within as well as outside atrophic areas. in eyes affected by GA, AO nir imaging allows high resolution documentation of the extent of RPE damage. this also revealed that a complex, dynamic process of redistribution of hyporeflective clumps throughout the posterior pole precedes and accompanies the emergence and progression of atrophy. therefore, these clumps are probably also a biomarker of rpe damage. AO NIR imaging may, therefore, be of interest to detect the earliest stages, to document the retinal pathology and to monitor the progression oF GA. (ClinicalTrials.gov number, NCT01546181.).
Camalet S.,University Pierre and Marie Curie
European Physical Journal B | Year: 2011
We determine and study the steady state of two independent two-level systems weakly coupled to a stationary non-equilibrium environment. Whereas this bipartite state is necessarily uncorrelated if the splitting energies of the two-level systems are different from each other, it can be entangled if they are equal. For identical two-level systems interacting with two bosonic heat baths at different temperatures, we discuss the influence of the baths temperatures and coupling parameters on their entanglement. Geometric properties, such as the baths dimensionalities and the distance between the two-level systems, are relevant. A regime is found where the steady state is a statistical mixture of the product ground state and of the entangled singlet state with respective weights 2/3 and 1/3. © 2011 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
van Baalen M.,University Pierre and Marie Curie
Interface Focus | Year: 2013
Evolution can be characterized as a process that shapes and maintains information across generations. It is also widely acknowledged that information may play a pivotal role in many other ecological processes. Most of the ecologically relevant information (and some important evolutionary information too) is of a very subjective and analogue kind: individuals use cues that may carry information useful only to them but not to others. This is a problem because most information theory has been developed for objective and discrete information. Can information theory be extended to this theory to incorporate multiple forms of information, each with its own (physical) carriers and dynamics? Here, I will not review all the possible roles that information can play, but rather what conditions an appropriate theory should satisfy. The most promising starting point is provided by entropy measures of conditional probabilities (using the so-called Kullback-Leibler divergence), allowing an assessment of how acquiring information can lead to an increase in fitness. It is irrelevant (to a certain extent) where the information comes from- genes, experience or culture-but it is important to realize that information is not merely subjective but its value should be evaluated in fitness terms, and it is here that evolutionary theory has an enormous potential. A number of important stumbling points remain, however; namely, the identification of whose fitness it concerns andwhat role the spatio-temporal dynamics plays (which is tightly linked to the nature of the physical carriers of the information and the processes that impact on it). © 2013 The Author(s) Published by the Royal Society. All rights reserved.
Bolopion A.,FEMTO ST Institute |
Regnier S.,University Pierre and Marie Curie
IEEE Transactions on Automation Science and Engineering | Year: 2013
This paper presents a review of the major haptic feedback teleoperation systems for micromanipulation. During the last decade, the handling of micrometer-sized objects has become a critical issue. Fields of application from material science to electronics demonstrate an urgent need for intuitive and flexible manipulation systems able to deal with small-scale industrial projects and assembly tasks. Two main approaches have been considered: fully automated tasks and manual operation. The first one require fully pre determined tasks, while the later necessitates highly trained operators. To overcome these issues the use of haptic feedback teleoperation where the user manipulates the tool through a joystick whilst feeling a force feedback, appears to be a promising solution as it allows high intuitiveness and flexibility. Major advances have been achieved during this last decade, starting with systems that enable the operator to feel the substrate topology, to the current state-of-the-art where 3D haptic feedback is provided to aid manipulation tasks. This paper details the major achievements and the solutions that have been developed to propose 3D haptic feedback for tools that often lack 3D force measurements. The use of virtual reality to enhance the immersion is also addressed. The strategies developed provide haptic feedback teleoperation systems with a high degree of assistance and for a wide range of micromanipulation tools. Based on this expertise on haptic for micromanipulation and virtual reality assistance it is now possible to propose microassembly systems for objects as small as 1 to 10 micrometers. This is a mature field and will benefit small-scale industrial projects where precision and flexibility in microassembly are required. © 2013 IEEE.
Rimola A.,Autonomous University of Barcelona |
Costa D.,Ecole Nationale Superieure de Chimie de Paris |
Sodupe M.,Autonomous University of Barcelona |
Lambert J.-F.,University Pierre and Marie Curie |
Ugliengo P.,University of Turin
Chemical Reviews | Year: 2013
The physicochemical reasons behind the delicate equilibrium established between the adsorbed and the mobile phases are ultimately dictated by the specific interactions between silica surface functionalities and the adsorbate, resulting in different adsorption constants. There are many reasons to report on silica interacting with biomolecules. The most obvious one is that on the Earth's crust, oxygen and silicon are the most abundant atomic species, with percentages of 45.5% and 27.2%, respectively, which manifests itself in a large variety of silica and silicate minerals so that the contact between living matter and these materials is ubiquitous. The adsorption of other molecules, which are not rigorously biomolecules, has also been addressed in section 9, because their behaviors mimic that of residues to be found in real proteins. From the methodological point of view, only methods able to properly handle relatively weak intermolecular interactions should be adopted.
Kwon Y.-O.,Woods Hole Oceanographic Institution |
Frankignoul C.,University Pierre and Marie Curie
Climate Dynamics | Year: 2012
The Atlantic meridional overturning circulation (AMOC) in the last 250 years of the 700-year-long present-day control integration of the Community Climate System Model version 3 with T85 atmospheric resolution exhibits a red noise-like irregular multi-decadal variability with a persistence longer than 10 years, which markedly contrasts with the preceding ~300 years of very regular and stronger AMOC variability with ~20 year periodicity. The red noise-like multi-decadal AMOC variability is primarily forced by the surface fluxes associated with stochastic changes in the North Atlantic Oscillation (NAO) that intensify and shift northward the deep convection in the Labrador Sea. However, the persistence of the AMOC and the associated oceanic anomalies that are directly forced by the NAO forcing does not exceed about 5 years. The additional persistence originates from anomalous horizontal advection and vertical mixing, which generate density anomalies on the continental shelf along the eastern boundary of the subpolar gyre. These anomalies are subsequently advected by the mean boundary current into the northern part of the Labrador Sea convection region, reinforcing the density changes directly forced by the NAO. As no evidence was found of a clear two-way coupling with the atmosphere, the multi-decadal AMOC variability in the last 250 years of the integration is an ocean-only response to stochastic NAO forcing with a delayed positive feedback caused by the changes in the horizontal ocean circulation. © 2011 Springer-Verlag.
Giannopulu I.,University Pierre and Marie Curie
Cognitive Processing | Year: 2013
This review addresses the central role played by multimodal interactions in neurocognitive development. We first analyzed our studies of multimodal verbal and nonverbal cognition and emotional interactions within neuronal, that is, natural environments in typically developing children. We then tried to relate them to the topic of creating artificial environments using mobile toy robots to neurorehabilitate severely autistic children. By doing so, both neural/natural and artificial environments are considered as the basis of neuronal organization and reorganization. The common thread underlying the thinking behind this approach revolves around the brain's intrinsic properties: neuroplasticity and the fact that the brain is neurodynamic. In our approach, neural organization and reorganization using natural or artificial environments aspires to bring computational perspectives into cognitive developmental neuroscience. © 2013 Marta Olivetti Belardinelli and Springer-Verlag Berlin Heidelberg.
Ostojic S.,Columbia University |
Ostojic S.,University Pierre and Marie Curie |
Brunel N.,University of Paris Descartes
PLoS Computational Biology | Year: 2011
Neurons transform time-varying inputs into action potentials emitted stochastically at a time dependent rate. The mapping from current input to output firing rate is often represented with the help of phenomenological models such as the linearnonlinear (LN) cascade, in which the output firing rate is estimated by applying to the input successively a linear temporal filter and a static non-linear transformation. These simplified models leave out the biophysical details of action potential generation. It is not a priori clear to which extent the input-output mapping of biophysically more realistic, spiking neuron models can be reduced to a simple linear-nonlinear cascade. Here we investigate this question for the leaky integrate-andfire (LIF), exponential integrate-and-fire (EIF) and conductance-based Wang-Buzsáki models in presence of background synaptic activity. We exploit available analytic results for these models to determine the corresponding linear filter and static non-linearity in a parameter-free form. We show that the obtained functions are identical to the linear filter and static nonlinearity determined using standard reverse correlation analysis. We then quantitatively compare the output of the corresponding linear-nonlinear cascade with numerical simulations of spiking neurons, systematically varying the parameters of input signal and background noise. We find that the LN cascade provides accurate estimates of the firing rates of spiking neurons in most of parameter space. For the EIF and Wang-Buzsáki models, we show that the LN cascade can be reduced to a firing rate model, the timescale of which we determine analytically. Finally we introduce an adaptive timescale rate model in which the timescale of the linear filter depends on the instantaneous firing rate. This model leads to highly accurate estimates of instantaneous firing rates. © 2011 Ostojic, Brunel.
Cormier L.,University Pierre and Marie Curie |
Cuello G.J.,Laue Langevin Institute
Physical Review B - Condensed Matter and Materials Physics | Year: 2011
Neutron diffraction with isotopic substitution (Mg25/natMg) is used to investigate the Mg environment in MgSiO3 glass. The neutron-diffraction data are coupled with x-ray diffraction and a reverse Monte Carlo modeling. The Mg environment can be fully resolved from other contributions. We show that two Mg-O contributions are present at ∼1.99 ± 0.01 Å and 2.21 ± 0.01 Å, with an average coordination number of 4.5 ± 0.1 O neighbors around Mg. These distorted Mg sites participate in an inhomogeneous distribution of Mg atoms. This organization results from the liquid state and has implications in understanding the immiscibility gap and glass forming ability. © 2011 American Physical Society.
Guerrero S.,University Pierre and Marie Curie |
Imanuvilov O.Y.,Colorado State University
ESAIM - Control, Optimisation and Calculus of Variations | Year: 2013
In this paper we deal with the null controllability problem for the heat equation with a memory term by means of boundary controls. For each positive final time T and when the control is acting on the whole boundary, we prove that there exists a set of initial conditions such that the null controllability property fails. © 2012 EDP Sciences, SMAI.
Berenbaum F.,University Pierre and Marie Curie
Osteoarthritis and Cartilage | Year: 2013
Osteoarthritis (OA) has long been considered a " wear and tear" disease leading to loss of cartilage. OA used to be considered the sole consequence of any process leading to increased pressure on one particular joint or fragility of cartilage matrix. Progress in molecular biology in the 1990s has profoundly modified this paradigm. The discovery that many soluble mediators such as cytokines or prostaglandins can increase the production of matrix metalloproteinases by chondrocytes led to the first steps of an " inflammatory" theory. However, it took a decade before synovitis was accepted as a critical feature of OA, and some studies are now opening the way to consider the condition a driver of the OA process. Recent experimental data have shown that subchondral bone may have a substantial role in the OA process, as a mechanical damper, as well as a source of inflammatory mediators implicated in the OA pain process and in the degradation of the deep layer of cartilage. Thus, initially considered cartilage driven, OA is a much more complex disease with inflammatory mediators released by cartilage, bone and synovium. Low-grade inflammation induced by the metabolic syndrome, innate immunity and inflammaging are some of the more recent arguments in favor of the inflammatory theory of OA and highlighted in this review. © 2012 Osteoarthritis Research Society International.
Colomban Ph.,University Pierre and Marie Curie
Fuel Cells | Year: 2013
The first objectives of Chemistry are the description of the reactions and the determination of the composition of each compound involved in a process. Solid State Chemistry tries to establish the composition and the structure, the (micro/nano)structure as well as the relationship between composition, structure, and material properties. In the case of Hydrogen element, most of the literature data do not follow this approach: the contents of protons and associated protonic species are rarely measured. Based on the examples of proton conducting materials with different water content: (i) high (sol-gel materials), (ii) medium (polyaniline (PANI) polymer and salts), and (iii) anhydrous (protonated perovskites), we will discuss the main methods (TGA, thermal expansion, infrared and Raman spectroscopy, incoherent (elastic, quasi- and in-elastic) and coherent neutron scattering, neutronography, NRA, RBS/ERDA, ERCS, etc.) able to detect/measure the proton content and/or to identify the nature of the protonic species and their interaction with the host framework: hydroxyl ion, "free" proton, physi/chemi-sorbed water, strong H-bonded water, proton hydrates, aquo-hydroxycarbonates, etc. Emphasis is given to the difficulties encountered for the identification and the quantification of protonic species and the way to overcome them, in particular the discrimination between the surface and bulk moieties. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Gerolymos G.A.,University Pierre and Marie Curie
International Journal of Computational Fluid Dynamics | Year: 2013
This note reviews the widely used phased-lagged [Erdos, J. L., E. Alzner, and W. McNally. 1977. AIAA Journal 15: 1559-68.] approach and corresponding chorochronic interface relations [Gerolymos G. A., G. J. Michon, and J. Neubauer. 2002. Journal of Propulsion and Power 18: 1139-52.] and explores its potential extension to the approximate unsteady throughflow analysis of multistage turbomachinery. The basic relations pertaining to the binary blade-row interaction case, for which chorochronic periodicity is exact in a phase-averaged rans framework, are briefly formulated, and selected computational examples illustrate the application of the method. Then, the filtered chorochronic interface is defined as the unsteady counterpart of the well-known mixing-plane concept. This interface takes into account only those tθ-waves which are compatible with the interaction of the immediately upstream and downstream blade-rows. The concept, which is similar to the decomposition-and-superposition method [Li, H. D., and L. He. 2005. ASME J ournal of Turbomachinery 127: 589-98.], is illustrated by 3-D computations of a 1/2-stage transonic compressor. © 2013 Copyright Taylor and Francis Group, LLC.
Ferriere R.,Ecole Normale Superieure de Paris |
Ferriere R.,University of Arizona |
Legendre S.,University Pierre and Marie Curie
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2013
Adaptive dynamics theory has been devised to account for feedbacks between ecological and evolutionary processes. Doing so opens new dimensions to and raises new challenges about evolutionary rescue. Adaptive dynamics theory predicts that successive trait substitutions driven by eco-evolutionary feedbacks can gradually erode population size or growth rate, thus potentially raising the extinction risk. Even a single trait substitution can suffice to degrade population viability drastically at once and cause 'evolutionary suicide'. In a changing environment, a population may track a viable evolutionary attractor that leads to evolutionary suicide, a phenomenon called 'evolutionary trapping'. Evolutionary trapping and suicide are commonly observed in adaptive dynamics models in which the smooth variation of traits causes catastrophic changes in ecological state. In the face of trapping and suicide, evolutionary rescue requires that the population overcome evolutionary threats generated by the adaptive process itself. Evolutionary repellors play an important role in determining how variation in environmental conditions correlates with the occurrence of evolutionary trapping and suicide, and what evolutionary pathways rescue may follow. In contrast with standard predictions of evolutionary rescue theory, low genetic variation may attenuate the threat of evolutionary suicide and small population sizes may facilitate escape from evolutionary traps. © 2012 The Author(s) Published by the Royal Society. All rights reserved.
Winter C.,University of Vienna |
Bouvier T.,Montpellier University |
Weinbauer M.G.,University Pierre and Marie Curie |
Thingstad T.F.,University of Bergen
Microbiology and Molecular Biology Reviews | Year: 2010
A trade-off between strategies maximizing growth and minimizing losses appears to be a fundamental property of evolving biological entities existing in environments with limited resources. In the special case of unicellular planktonic organisms, the theoretical framework describing the trade-offs between competition and defense specialists is known as the "killing the winner" hypothesis (KtW). KtW describes how the availability of resources and the actions of predators (e.g., heterotrophic flagellates) and parasites (e.g., viruses) determine the composition and biogeochemical impact of such organisms. We extend KtW conceptually by introducing size- or shape-selective grazing of protozoans on prokaryotes into an idealized food web composed of prokaryotes, lytic viruses infecting prokaryotes, and protozoans. This results in a hierarchy analogous to a Russian doll, where KtW principles are at work on a lower level due to selective viral infection and on an upper level due to size- or shape-selective grazing by protozoans. Additionally, we critically discuss predictions and limitations of KtW in light of the recent literature, with particular focus on typically neglected aspects of KtW. Many aspects of KtW have been corroborated by in situ and experimental studies of isolates and natural communities. However, a thorough test of KtW is still hampered by current methodological limitations. In particular, the quantification of nutrient uptake rates of the competing prokaryotic populations and virus population-specific adsorption and decay rates appears to be the most daunting challenge for the years to come. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Wan C.,University Pierre and Marie Curie
Mathematics of Operations Research | Year: 2012
This work shows that the formation of a finite number of coalitions in a nonatomic network congestion game benefits everyone. At the equilibrium of the composite game played by coalitions and individuals, the average cost to each coalition and the individuals' common cost are all lower than in the corresponding nonatomic game (without coalitions). The individuals' cost is lower than the average cost to any coalition. Similarly, the average cost to a coalition is lower than that to any larger coalition. Whenever some members of a coalition become individuals, the individuals' payoff is increased. In the case of a unique coalition, both the average cost to the coalition and the individuals' cost are decreasing with respect to the size of the coalition. In a sequence of composite games, if a finite number of coalitions are fixed, and the size of the remaining coalitions goes to zero, the equilibria of these games converge to the equilibrium of a composite game played by the same fixed coalitions and the remaining individuals. © 2012 INFORMS.
Dujon B.,University Pierre and Marie Curie
Nature Reviews Genetics | Year: 2010
Over the past few years, genome sequences have become available from an increasing range of yeast species, which has led to notable advances in our understanding of evolutionary mechanisms in eukaryotes. Yeasts offer us a unique opportunity to examine how molecular and reproductive mechanisms combine to affect genome architectures and drive evolutionary changes over a broad range of species. This Review summarizes recent progress in understanding the molecular mechanisms-such as gene duplication, mutation and acquisition of novel genetic material-that underlie yeast evolutionary genomics. I also discuss how results from yeasts can be extended to other eukaryotes. © 2010 Macmillan Publishers Limited. All rights reserved.
Metin C.,University Pierre and Marie Curie
Medecine/Sciences | Year: 2014
In a landmark paper published in 1977, G. Albrecht-Buehler described a primary cilium on the surface of migrating fibroblasts, and noticed that cilia are oriented parallel to the direction of migration of fibroblasts. While the presence of a primary cilium on neural progenitors and on post-mitotic neurons was noted long ago, it has been observed on migrating cortical interneurons only recently. As in fibroblasts, the cilium of interneurons controls the directionality of migration. It plays an important role in the reorientation of cortical interneurons towards the cortical plate. The morphogen Shh, which is expressed in the migratory pathway of interneurons, is one of the signals that control this reorientation. © 2014 médecine/sciences-Inserm.
Teixeira M.T.,University Pierre and Marie Curie
Frontiers in Oncology | Year: 2013
In many somatic human tissues, telomeres shorten progressively because of the DNA-end replication problem. Consequently, cells cease to proliferate and are maintained in a metabolically viable state called replicative senescence. These cells are characterized by an activation of DNA damage checkpoints stemming from eroded telomeres, which are bypassed in many cancer cells. Hence, replicative senescence has been considered one of the most potent tumor suppressor pathways. However, the mechanism through which short telomeres trigger this cellular response is far from being understood. When telomerase is removed experimentally in Saccharomyces cerevisiae, telomere shortening also results in a gradual arrest of population growth, suggesting that replicative senescence also occurs in this unicellular eukaryote. In this review, we present the key steps that have contributed to the understanding of the mechanisms underlying the establishment of replicative senescence in budding yeast. As in mammals, signals stemming from short telomeres activate the DNA damage checkpoints, suggesting that the early cellular response to the shortest telomere(s) is conserved in evolution. Yet closer analysis reveals a complex picture in which the apparent single checkpoint response may result from a variety of telomeric alterations expressed in the absence of telomerase. Accordingly, the DNA replication of eroding telomeres appears as a critical challenge for senescing budding yeast cells and the easy manipulation of S. cerevisiae is providing insights into the way short telomeres are integrated into their chromatin and nuclear environments. Finally, the loss of telomerase in budding yeast triggers a more general metabolic alteration that remains largely unexplored. Thus, telomerase-deficient S. cerevisiae cells may have more common points than anticipated with somatic cells, in which telomerase depletion is naturally programed, thus potentially inspiring investigations in mammalian cells. © 2013 Teixeira.
Bokobza L.,University Pierre and Marie Curie
Polymers for Advanced Technologies | Year: 2012
Multiwall carbon nanotube-filled elastomers are prepared by solution blending using a sonication process. It is shown that the processing conditions have a strong effect on the composite properties especially on electrical properties, which are very sensitive to nanotube dispersion within the elastomeric matrix. The percolation threshold is seen to be shifted to a lower nanotube content than that previously reported. With regard to the unfilled elastomer, large increases in the elastic and tensile moduli are obtained with the nanotube loading, thus highlighting the potential of this type of particles as reinforcing fillers for elastomeric matrices. Raman spectroscopy under strain has been used to evaluate the strength of the polymer-filler interface. Weak interfacial interactions are deduced, but the debundling of the nanotubes and the orientational effects of the polymeric chains are observed when the composite is submitted to a uniaxial deformation. © 2012 John Wiley & Sons, Ltd.
Klumperman J.,University Utrecht |
Raposo G.,University Pierre and Marie Curie |
Raposo G.,French National Center for Scientific Research
Cold Spring Harbor Perspectives in Biology | Year: 2014
Live-cell imaging reveals the endolysosomal system as a complex and highly dynamic network of interacting compartments. Distinct types of endosomes are discerned by kinetic, molecular, and morphological criteria. Although none of these criteria, or combinations thereof, can capture the full complexity of the endolysosomal system, they are extremely useful for experimental purposes. Some membrane domain specializations and specific morphological characteristics can only be seen by ultrastructural analysis after preparation for electron microscopy (EM). Immuno-EM allows a further discrimination of seemingly identical compartments by their molecular makeup. In this review we provide an overview of the ultrastructural characteristics and membrane organization of endosomal compartments, along with their organizing machineries. ©2014 Cold Spring Harbor Laboratory Press; all rights reserved.
Arrondeau J.,University Pierre and Marie Curie
Discovery medicine | Year: 2010
Every new anti-cancer drug or drug combination is evaluated for safety and efficacy before being approved. Clinical development of cytotoxic anticancer drugs classically follows three main phases. Phase I trials represent the first administration of a new drug or combination to human beings. Their primary goal is to determine the recommended phase two dose and also to collect toxicity, pharmacokinetic and pharmacodynamic data. Phase II trials are screening studies aimed at identifying signals of anti-tumor activity in a specific tumor type and setting. Phase III trials aim to compare the efficacy of a new treatment with standard of care and can lead to regulatory approval when positive. The recent emergence of molecularly targeted agents has challenged the traditional developmental pathway for anti-cancer drugs. Using biomarker enriched patient populations has been successful for a few agents. Otherwise, new types of trials have been proposed for these agents in an attempt to elucidate their mechanism of action, such as phase 0 trials and "window of opportunity" trials. These two types of trials and the classical three phase trials are discussed in detail.
Esposito-Farese G.,University Pierre and Marie Curie
Mass and Motion in General Relativity | Year: 2011
Although general relativity (GR) passes all present experimental tests with flying colors, it remains important to study alternative theories of gravity for several theoretical and phenomenological reasons that we recall in these lecture notes. The various possible ways of modifying GR are presented, and we notably show that the motion of massive bodies may be changed even if one assumes that matter is minimally coupled to the metric as in GR. This is illustrated with the particular case of scalar-tensor theories of gravity, whose Fokker action is discussed, and we also mention the consequences of the no-hair theorem on the motion of black holes. The finite size of the bodies modifies their motion with respect to pointlike particles, and we give a simple argument showing that the corresponding effects are generically much larger in alternative theories than in GR. We also discuss possible modifications of Newtonian dynamics (MOND) at large distances, which have been proposed to avoid the dark matter hypothesis. We underline that all the previous classes of alternatives to GR may a priori be used to predict such a phenomenology, but that they generically involve several theoretical and experimental difficulties. © 2011 Springer Science+Business Media B.V.
Deleuze C.,Icm Institute Du Cerveau Et Of La Moelle Epiniere |
Pazienti A.,European Brain Research Institute |
Bacci A.,Icm Institute Du Cerveau Et Of La Moelle Epiniere |
Bacci A.,University Pierre and Marie Curie
Current Opinion in Neurobiology | Year: 2014
Fast synaptic inhibition sculpts all forms of cortical activity by means of a specialized connectivity pattern between highly heterogeneous inhibitory interneurons and principal excitatory cells. Importantly, inhibitory neurons connect also to each other extensively, following a detailed blueprint, and, indeed, specific forms of disinhibition affect important behavioral functions. Here we discuss a peculiar form of cortical disinhibition: the massive autaptic self-inhibition of parvalbumin-(PV) positive basket cells. Despite being described long ago, autaptic inhibition onto PV basket cells is rarely included in cortical circuit diagrams, perhaps because of its still elusive function. We propose here a potential dual role of autaptic feedback inhibition in temporally coordinating PV basket cells during cortical network activity. © 2013 Elsevier Ltd.
Maugin G.A.,University Pierre and Marie Curie
Continuum Mechanics and Thermodynamics | Year: 2013
In a period of a few decades, the formulation known as the principle of virtual power (PVP) has gained a prominent place among the most efficient tools in the thermomechanics of continua. Strongly marked by a "continental" (French-Italian) influence, it has successfully incorporated the basic invariances of modern continuum mechanics while capturing the spirit of twentieth-century analysis (generalized functions or distributions) in which it became synonymous of weak formulation. It proved to provide the surest and safest way to formulate complex theories of continua (so-called "generalized continuum mechanics", theory of coupled fields, etc) and approximate or generalized theories of structural members and the associated natural boundary conditions while preparing the way for the full thermomechanical formulation, providing the best setting for the proof of various mathematical theorems, and paving the way for modern numerical methods. The present contribution, illustrated by many examples of varying complexity, emphasizes the role of Paul Germain (1920-2009) in this formulation. The author, himself an active contributor and a never tired propagandist of the method, has participated in these developments during four decades and presents here his witness but critical viewpoint, highlighting the difficult points and also the esthetically pleasing ones where necessary. © 2012 Springer-Verlag.
Leguillon D.,University Pierre and Marie Curie
International Journal of Solids and Structures | Year: 2011
Determination of the length of a short crack at the root of a v-notch, from a full kinematic field measurement, is performed using a direct method. It is based on a matched asymptotic expansions procedure together with the theory of singularities. The first corrective term of the outer expansion can be straightforwardly expressed as a function of the crack length. Its extraction is achieved through the calculation of the associated generalized stress intensity factors for elastic homogeneous materials as well as bimaterials. Numerical simulations are carried out on a finite element solution disturbed by a random noise. In addition, the method used to compute the generalized stress intensity factors proved accurate and robust. © 2010 Elsevier Ltd. All rights reserved.
Martin J.,University Pierre and Marie Curie |
Vennin V.,University of Portsmouth
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016
We investigate the quantumness of primordial cosmological fluctuations and its detectability. The quantum discord of inflationary perturbations is calculated for an arbitrary splitting of the system, and shown to be very large on super-Hubble scales. This entails the presence of large quantum correlations, due to the entangled production of particles with opposite momentums during inflation. To determine how this is reflected at the observational level, we study whether quantum correlators can be reproduced by a nondiscordant state, i.e. a state with vanishing discord that contains classical correlations only. We demonstrate that this can be done for the power spectrum, the price to pay being twofold: first, large errors in other two-point correlation functions that cannot however be detected since they are hidden in the decaying mode; second, the presence of intrinsic non-Gaussianity, the detectability of which remains to be determined but which could possibly rule out a nondiscordant description of the cosmic microwave background. If one abandons the idea that perturbations should be modeled by quantum mechanics and wants to use a classical stochastic formalism instead, we show that any two-point correlators on super-Hubble scales can be exactly reproduced regardless of the squeezing of the system. The latter becomes important only for higher order correlation functions that can be accurately reproduced only in the strong squeezing regime. © 2016 American Physical Society.
Blanchet L.,University Pierre and Marie Curie
Mass and Motion in General Relativity | Year: 2011
Reliable predictions of general relativity theory are extracted using approximation methods. Among these, the powerful post-Newtonian approximation provides us with our best insights into the problems of motion and gravitational radiation of systems of compact objects. This approximation has reached an impressive mature status, because of important progress regarding its theoretical foundations, and the successful construction of templates of gravitational waves emitted by inspiralling compact binaries. The post-Newtonian predictions are routinely used for searching and analyzing the very weak signals of gravitational waves in current generations of detectors. High-accuracy comparisons with the results of numerical simulations for the merger and ring-down of binary black holes are going on. In this article we give an overview on the general formulation of the post-Newtonian approximation and present up-to-date results for the templates of compact binary inspiral. © 2011 Springer Science+Business Media B.V.
Kim D.Y.,Carnegie Institution of Washington |
Stefanoski S.,Carnegie Institution of Washington |
Kurakevych O.O.,Carnegie Institution of Washington |
Kurakevych O.O.,University Pierre and Marie Curie |
Strobel T.A.,Carnegie Institution of Washington
Nature Materials | Year: 2015
Silicon is ubiquitous in contemporary technology. The most stable form of silicon at ambient conditions takes on the structure of diamond (cF8, d-Si) and is an indirect bandgap semiconductor, which prevents it from being considered as a next-generation platform for semiconductor technologies. Here, we report the formation of a new orthorhombic allotrope of silicon, Si 24, using a novel two-step synthesis methodology. First, a Na 4 Si 24 precursor was synthesized at high pressure; second, sodium was removed from the precursor by a thermal process. The Cmcm structure of Si 24, which has 24 Si atoms per unit cell (oC24), contains open channels along the crystallographic a-axis that are formed from six- and eight-membered sp 3 silicon rings. This new allotrope possesses a quasidirect bandgap near 1.3 eV. Our combined experimental/theoretical study expands the known allotropy for element fourteen and the unique high-pressure precursor synthesis methodology demonstrates the potential for new materials with desirable properties. © 2015 Macmillan Publishers Limited. All rights reserved.
Wassmann K.,University Pierre and Marie Curie |
Wassmann K.,CNRS Developmental Biology Laboratory
Cell Cycle | Year: 2013
Meiotic divisions (meiosis I and II ) are specialized cell divisions to generate haploid gametes. The first meiotic division with the separation of chromosomes is named reductional division. The second division, which takes place immediately after meiosis I without intervening S-phase, is equational, with the separation of sister chromatids, similar to mitosis. This meiotic segregation pattern requires the two-step removal of the cohesin complex holding sister chromatids together: cohesin is removed from chromosome arms that have been subjected to homologous recombination in meiosis I and from the centromere region in meiosis II . Cohesin in the centromere region is protected from removal in meiosis I, but this protection has to be removed-deprotected-for sister chromatid segregation in meiosis II . Whereas the mechanisms of cohesin protection are quite well understood, the mechanisms of deprotection have been largely unknown until recently. In this review I summarize our current knowledge on cohesin deprotection. © 2013 Landes Bioscience.
Holzenberger M.,University Pierre and Marie Curie
Nestle Nutrition Workshop Series: Pediatric Program | Year: 2011
Insulin and insulin-like signaling regulate survival and lifespan in a variety of animal species, from nematodes and flies to higher vertebrates and mammals. Recently, it was shown that brain IGF-I receptor and brain IRS2 control mammalian lifespan, and that this occurs through neuroendocrine mechanisms, control of energy metabolism and modified stress resistance. Furthermore, it was demonstrated that insulin receptor substrate molecules are implicated downstream of insulin and IGF receptors in the extension of lifespan. We showed recently that early postnatal diet plays a significant role in the development of the somatotropic axis, and that part of the neuroendocrine plasticity of growth hormone secretion depends on postnatal nutrition. We also showed that the prevalence of cardiovascular and metabolic pathologies varied with the development of somatotropic function. Neuroendocrine pathways are also prime targets for pharmacological treatments, and administration of rapamycin to adult mice has indeed recently been reported to prolong lifespan in mice. With respect to human aging, new studies identified several genes of the somatotropic axis as longevity determinants, and a recent study shows that variants of FOXO3A, downstream signaling molecule in the insulin/IGF pathway, are associated with extreme longevity in humans. Finally, several functional mutations of the human IGF-IR have been discovered in centenarians. Copyright © 2011 S. Karger AG, Basel.
Mega J.L.,Harvard University |
Simon T.,Assistance Publique Hopitaux de Paris |
Simon T.,University Pierre and Marie Curie |
Simon T.,National Health Research Institute
The Lancet | Year: 2015
Antithrombotic drugs, which include antiplatelet and anticoagulant therapies, prevent and treat many cardiovascular disorders and, as such, are some of the most commonly prescribed drugs worldwide. The first drugs designed to inhibit platelets or coagulation factors, such as the antiplatelet clopidogrel and the anticoagulant warfarin, significantly reduced the risk of thrombotic events at the cost of increased bleeding in patients. However, both clopidogrel and warfarin have some pharmacological limitations including interpatient variability in antithrombotic effects in part due to the metabolism, interactions (eg, drug, environment, and genetic), or targets of the drugs. Increased knowledge of the pharmacology of antithrombotic drugs and the mechanisms underlying thrombosis has led to the development of newer drugs with faster onset of action, fewer interactions, and less interpatient variability in their antithrombotic effects than previous antithrombotic drugs. Treatment options now include the next-generation antiplatelet drugs prasugrel and ticagrelor, and, in terms of anticoagulants, inhibitors that directly target factor IIa (dabigatran) or Xa (rivaroxaban, apixaban, edoxaban) are available. In this Series paper we review the pharmacological properties of these most commonly used oral antithrombotic drugs, and explore the development of antiplatelet and anticoagulant therapies. © 2015 Elsevier Ltd.
Bushdid C.,Rockefeller University |
Bushdid C.,University Pierre and Marie Curie |
Magnasco M.O.,Rockefeller University |
Vosshall L.B.,Rockefeller University |
And 2 more authors.
Science | Year: 2014
Humans can discriminate several million different colors and almost half a million different tones, but the number of discriminable olfactory stimuli remains unknown. The lay and scientific literature typically claims that humans can discriminate 10,000 odors, but this number has never been empirically validated. We determined the resolution of the human sense of smell by testing the capacity of humans to discriminate odor mixtures with varying numbers of shared components. On the basis of the results of psychophysical testing, we calculated that humans can discriminate at least 1 trillion olfactory stimuli. This is far more than previous estimates of distinguishable olfactory stimuli. It demonstrates that the human olfactory system, with its hundreds of different olfactory receptors, far outperforms the other senses in the number of physically different stimuli it can discriminate.
Colomban P.,University Pierre and Marie Curie
Journal of Raman Spectroscopy | Year: 2012
The miniaturisation of laser sources, charge-coupled device electronic control boxes and increasing Lap-top computer capacity led to a revolution in Raman spectrometry: Measurements can be made outside the laboratory with transportable, mobile and ultramobile instruments, even in severe conditions (e.g. rock shelter in mountains). However, many specific difficulties must be previously solved: The variety of mobile laser sources remains limited to red and green excitations, the positioning/focusing and protection against solar/bulb lighting are difficult and, more importantly, the spectral resolution and spectral window are limited. Nevertheless, the definition of good procedures and the use of advanced optics allow the on-site analysis of various cultural heritage materials: pigments of pastels, miniatures, drawings, glasses, enamels and glazes, rock art, crystalline and amorphous phases of pottery, enamelled glass artefacts or stained glasses, bronze and brass patinas, etc. Simultaneously, mobile instruments equipped with a telescope and pulsed Yttrium Aluminum Garnet laser are being implemented for planetary mission (Mars). The present state of the art and future development are discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Joanny J.F.,University Pierre and Marie Curie
The European physical journal. E, Soft matter | Year: 2013
Using active gel theory we study theoretically the properties of the cortical actin layer of animal cells. The cortical layer is described as a non-equilibrium wetting film on the cell membrane. The actin density is approximately constant in the layer and jumps to zero at its edge. The layer thickness is determined by the ratio of the polymerization velocity and the depolymerization rate of actin.
Laclef C.,University Pierre and Marie Curie
Medecine/Sciences | Year: 2014
The role of primary cilia in adult neurons remains elusive, however their developmental functions during brain morphogenesis have been recently highlighted thanks to mouse models. Unmistakably, they are needed for Hedgehog (Hh)-dependent patterning in the forebrain. Not only for Hh reception itself, but most importantly for a downstream event in the Hh transduction pathway, independent of Hh ligand: the Gli3 processing. Indeed, phenotypes due to cilia disruption in the developing brain, such as early patterning, olfactory bulb or corpus callosum formation, can be rescued by reintroducing Gli3-R (the short truncated form of Gli3 working as a transcriptional repressor of Hh target gene). In addition, primary cilia control the proliferation rate in different neural progenitors in the cortex, the hippocampus and the cerebellum; they are required for proper migration of interneurons. And cilia dysfunction is correlated with hydrocephaly, synaptogenesis defects and aberrant axonal tract projections. Most of these neurodevelopmental defects can be related to the various neurological features frequently observed across the ciliopathy spectrum. And thus, understanding the underlying mechanisms of these diverse functions of primary cilia in the brain is a new fundamental challenge. © 2014 médecine/sciences-Inserm.
Haumaitre C.,University Pierre and Marie Curie
Current Diabetes Reports | Year: 2013
Epigenetic mechanisms, including DNA methylation, histone modifications, and noncoding RNA expression, contribute to regulate islet cell development and function. Indeed, epigenetic mechanisms were recently shown to be involved in the control of endocrine cell fate decision, islet differentiation, β-cell identity, proliferation, and mature function. Epigenetic mechanisms can also contribute to the pathogenesis of complex diseases. Emerging knowledge regarding epigenetic mechanisms suggest that they may be involved in β-cell dysfunction and pathogenesis of diabetes. Epigenetic mechanisms could predispose to the diabetic phenotype such as decline of β-cell proliferation ability and β-cell failure, and account for complications associated with diabetes. Better understanding of epigenetic landscapes of islet differentiation and function may be useful to improve β-cell differentiation protocols and discover novel therapeutic targets for prevention and treatment of diabetes. © 2013 Springer Science+Business Media New York.
Roze D.,French National Center for Scientific Research |
Roze D.,University Pierre and Marie Curie
PLoS Biology | Year: 2012
Understanding the evolutionary advantage of sexual reproduction remains one of the most fundamental questions in evolutionary biology. Most of the current hypotheses rely on the fact that sex increases genetic variation, thereby enhancing the efficiency of natural selection; an important body of theoretical work has defined the conditions under which sex can be favoured through this effect. Over the last decade, experimental evolution in model organisms has provided evidence that sex indeed allows faster rates of adaptation. A new study on facultatively sexual rotifers shows that increased rates of sex can be favoured during adaptation to new environmental conditions and explores the cause of this effect. The results provide support for the idea that the benefits of increasing genetic variation may compensate for the short-term costs of sexual reproduction. © 2012 Denis Roze.
Bijlsma J.W.J.,University Utrecht |
Berenbaum F.,University Pierre and Marie Curie |
Lafeber F.P.J.G.,University Utrecht
The Lancet | Year: 2011
Osteoarthritis is thought to be the most prevalent chronic joint disease. The incidence of osteoarthritis is rising because of the ageing population and the epidemic of obesity. Pain and loss of function are the main clinical features that lead to treatment, including non-pharmacological, pharmacological, and surgical approaches. Clinicians recognise that the diagnosis of osteoarthritis is established late in the disease process, maybe too late to expect much help from disease-modifying drugs. Despite efforts over the past decades to develop markers of disease, still-imaging procedures and biochemical marker analyses need to be improved and possibly extended with more specific and sensitive methods to reliably describe disease processes, to diagnose the disease at an early stage, to classify patients according to their prognosis, and to follow the course of disease and treatment effectiveness. In the coming years, a better definition of osteoarthritis is expected by delineating different phenotypes of the disease. Treatment targeted more specifically at these phenotypes might lead to improved outcomes. © 2011 Elsevier Ltd.
Flandre P.,University Pierre and Marie Curie
AIDS | Year: 2013
Since the introduction of zidovudine, a nucleoside analogue reverse transcriptase inhibitor, there has been continuous improvement in the efficacy of antiretroviral treatments. Briefly, antiretroviral therapy moved from the era of zidovudine monotherapy to a combination of two analogues of the reverse transcriptase and then to triple-drug therapy with the introduction of protease inhibitors in 1996. The efficacy of triple-drug combinations was further consolidated with the introduction of the non-nucleoside analogue reverse transcriptase inhibitor. Beyond 1996, the impressive improvement in efficacy has implied that death and clinical endpoints could not be reasonably used as primary efficacy endpoints. Recent studies used plasma viral load as surrogate endpoints to evaluate efficacy of antiretroviral combinations. Progress in antiretroviral efficacy has also led to a move from superiority to noninferiority design. Methodological issues in noninferiority design have been already criticized, but recent trials provide a good opportunity for discussing some key features of that design. Recent studies are used to illustrate some inconsistencies in the choice of response rates, power and noninferiority margin. It appears that HIV noninferiority trials are overpowered by assuming lower success rates than those observed, enrolling a large number of patients and choosing a large margin. Consequently, failure to demonstrate noninferiority is uncommon. Novel designs or endpoints should be introduced emphasizing the expected benefits in terms of toxicity, adherence, resistance or costs. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.
LeFloch P.G.,University Pierre and Marie Curie |
Rendall A.D.,Max Planck Institute For Gravitationsphysik
Archive for Rational Mechanics and Analysis | Year: 2011
We investigate the initial value problem for the Einstein-Euler equations of general relativity under the assumption of Gowdy symmetry on T3, and we construct matter spacetimes with low regularity. These spacetimes admit both impulsive gravitational waves in the metric (for instance, Dirac mass curvature singularities propagating at light speed) and shock waves in the fluid (that is, discontinuities propagating at about the sound speed). Given an initial data set, we establish the existence of a future development, and we provide a global foliation in terms of a globally and geometrically defined time-function, closely related to the area of the orbits of the symmetry group. The main difficulty lies in the low regularity assumed on the initial data set which requires a distributional formulation of the Einstein-Euler equations. © 2011 Springer-Verlag.
Teillaud J.L.,University Pierre and Marie Curie
Methods in molecular biology (Clifton, N.J.) | Year: 2012
The development of therapeutic monoclonal antibodies over the last 35 years has led to the emergence of a new class of useful therapeutic molecules. These "first generation" antibodies have been obtained thanks to the conjugated and huge efforts of both academic and biotech researchers. About 30 monoclonal antibodies are currently approved for therapeutic use in Europe, USA, and China. Strikingly, only a restricted number of these antibodies are immunoglobulin fragments, single variable domains, or multiunit formats based on the engineering of immunoglobulin variable domains. In the present chapter, we will review the major steps of the therapeutic antibodies history and we will highlight the enormous potential of antibody fragments, either used as multiunits such as bispecific antibodies, single units, or as cell modifiers such as intrabodies or cell surface-expressed molecules.
Courty A.,University Pierre and Marie Curie
Journal of Physical Chemistry C | Year: 2010
In this paper, the main parameters, which dictate the supracrystalline structure of silver nanocrystals selfassembled at the micrometer scale, are evidenced. They are the alkyl-chain length, the deposition temperature, the concentration of the colloidal solution and the nature of the substrate. By varying the deposition temperature (from 15° to 50 °C), from the same batch of nanocrystals (same size, same coating agent), dense (fcc and hcp) and loose (bcc) supracrystals or disordered arrangements (rcp) are produced. By tuning the nature of the substrate (HOPG or amorphous carbon) and its temperature, the final size of the supracrystals is controlled. Collective properties due to either nanocrystals ordering in 2D superlattices or in supracrystals (3D) are pointed out. These properties are either due to dipolar interactions with the appearance of coupled plasmon modes or to the attraction between nanocrystals, self-assembled via interdigitation of the alkylchains used as coating agents, which leads to coherent vibrations of nanocrystals in a supracrystal. © 2010 American Chemical Society.
Cances C.,University Pierre and Marie Curie
Networks and Heterogeneous Media | Year: 2010
We consider a simplified model for two-phase flows in one-dimensional heterogeneous porous media made of two different rocks. We focus on the effects induced by the discontinuity of the capillarity field at interface. We first consider a model with capillarity forces within the rocks, stating an existence/uniqueness result. Then we look for the asymptotic problem for vanishing capillarity within the rocks, remaining only on the interface. We show that either the solution to the asymptotic problem is the optimal entropy solution to a scalar conservation law with discontinuous flux, or it admits a non-classical shock at the interface modeling oil-trapping. © American Institute of Mathematical Sciences.
Jaffredo T.,University Pierre and Marie Curie
The International journal of developmental biology | Year: 2010
Since the era of the ancient Egyptians and Greeks, the avian embryo has been a subject of intense interest to visualize the first steps of development. It has served as a pioneer model to scrutinize the question of hematopoietic development from the beginning of the 20th century. It's large size and easy accessibility have permitted the development of techniques dedicated to following the origins and fates of different cell populations. Here, we shall review how the avian model has brought major contributions to our understanding of the development of the hematopoietic system in the past four decades and how these discoveries have influenced our knowledge of mammalian hematopoietic development. The discovery of an intra-embryonic source of hematopoietic cells and the developmental link between endothelial cells and hematopoietic cells will be presented. We shall then point to the pivotal role of the somite in the construction of the aorta and hematopoietic production and demonstrate how two somitic compartments cooperate to construct the definitive aorta. We shall finish by showing how fate-mapping experiments have allowed the identification of the tissue which gives rise to the sub-aortic mesenchyme. Taken together, this review aims to give an overview of how and to what extent the avian embryo has contributed to our knowledge of developmental hematopoiesis.
Belikov A.V.,University Pierre and Marie Curie |
Hu W.,University of Chicago
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013
Massive gravity, Galileon and braneworld models that modify gravity to explain cosmic acceleration utilize the nonlinear field interactions of the Vainshtein mechanism to screen fifth forces in high density regimes. These source-dependent interactions cause apparent equivalence principle violations. In the weakly screened regime violations can be especially prominent since the fifth forces are at near full strength. Since they can also be calculated perturbatively, we derive analytic solutions for the cubic Galileon: the motion of massive objects in compensated shells and voids and infall toward halos that are spherically symmetric. Using numerical techniques we show that these solutions are valid until the characteristic scale becomes comparable to the Vainshtein radius. We find a relative acceleration of more massive objects toward the center of a void and a reduction of the infall acceleration that increases with the mass ratio of the halos which can in principle be used to test the Vainshtein screening mechanism. © 2013 American Physical Society.
Pioline B.,University Pierre and Marie Curie
Journal of High Energy Physics | Year: 2010
Four-graviton, eight-derivative couplings in the low energy effective action of toroidal type II string compactifications are tightly constrained by U-duality invariance and by supersymmetry. In this note, we revisit earlier proposals for the automorphic form governing these couplings in dimension D = 3, 4, 5, 6, and propose that the correct automorphic form is the minimal theta series for the corresponding U-duality group. Evidence for this proposal comes from i) the matching of infinitesimal characters, ii) the fact that the Fourier coefficients have support on 1/2-BPS charges and iii) decompactification limits. In particular, we show that non-perturbative effects can be interpreted as 1/2-BPS instantons, or 1/2-BPS particles in one dimension higher (together with Taub-NUT instantons in the D = 3 case). Based on similar considerations, we also conjecture the form of 1/4-BPS saturated couplings such as ∇ 4R 4 couplings in the same dimensions.
Brennan B.,Royal Manchester Childrens Hospital |
Stiller C.,Childhood Cancer Research Group |
Bourdeaut F.,University Pierre and Marie Curie
The Lancet Oncology | Year: 2013
Extracranial rhabdoid tumours are rare, and often occur in infants. Although the kidney is the most common site, they can occur anywhere in the body. Most contain a biallelic inactivating mutation in SMARCB1, which is part of the chromatin remodelling complex SWI/SNF, and functions as a classic tumour suppressor gene. Despite multimodal therapy, outcome in rhabdoid tumours remains poor with only 31% of patients surviving to 1 year. The young age of patients limits use of radiotherapy, which, along with age, is an important prognostic factor. Because the tumours are rare, no standard therapeutic pathway exists, and no randomised trials have examined the role of new therapeutic approaches. Improved understanding of the biology and role of SMARCB1 has enabled identification of new targets for small molecule inhibitors to combine with chemotherapy backbones that we might establish from the current EpSSG and COG studies. © 2013 Elsevier Ltd.
Zinger L.,Max Planck Institute for Marine Microbiology |
Gobet A.,University Pierre and Marie Curie |
Gobet A.,French Atomic Energy Commission |
Pommier T.,CNRS Microbial Ecology
Molecular Ecology | Year: 2012
Aquatic environments harbour large and diverse microbial populations that ensure their functioning and sustainability. In the current context of global change, characterizing microbial diversity has become crucial, and new tools have been developed to overcome the methodological challenges posed by working with microbes in nature. The advent of Sanger sequencing and now next-generation sequencing technologies has enabled the resolution of microbial communities to an unprecedented degree of precision. However, to correctly interpret microbial diversity and its patterns this revolution must also consider conceptual and methodological matters. This review presents advances, gaps and caveats of these recent approaches when considering microorganisms in aquatic ecosystems. We also discuss potentials and limitations of the available methodologies, from water sampling to sequence analysis, and suggest alternative ways to incorporate results in a conceptual and methodological framework. Together, these methods will allow us to gain an unprecedented understanding of microbial diversity in aquatic ecosystems. © 2011 Blackwell Publishing Ltd.
Meye F.J.,Institute du Fer a Moulin |
Meye F.J.,French Institute of Health and Medical Research |
Meye F.J.,University Pierre and Marie Curie |
Adan R.A.H.,University Utrecht
Trends in Pharmacological Sciences | Year: 2014
Overconsumption of high caloric food plays an important role in the etiology of obesity. Several factors drive such hedonic feeding. High caloric food is often palatable. In addition, when an individual is sated, stress and food-related cues can serve as potent feeding triggers. A better understanding of the neurobiological underpinnings of food palatability and environmentally triggered overconsumption would aid the development of new treatment strategies. In the current review we address the pivotal role of the mesolimbic dopamine reward system in the drive towards high caloric palatable food and its relation to stress- and cue-induced feeding. We also discuss how this system may be affected by both established and potential anti-obesity drug targets. © 2013 Elsevier Ltd. All rights reserved.
Sprintall J.,University of California at San Diego |
Revelard A.,University Pierre and Marie Curie
Journal of Geophysical Research: Oceans | Year: 2014
The Indonesian Throughflow (ITF) is the only open pathway for interocean exchange between the Pacific and Indian Ocean basins at tropical latitudes. A proxy time series of ITF transport variability is developed using remotely sensed altimeter data. The focus is on the three outflow passages of Lombok, Ombai, and Timor that collectively transport the entire ITF into the Indian Ocean, and where direct velocity measurements are available to help ground-truth the transport algorithm. The resulting 18 year proxy time series shows strong interannual ITF variability. Significant trends of increased transport are found in the upper layer of Lombok Strait, and over the full depth in Timor Passage that are likely related to enhanced Pacific trade winds since the early 1990s. The partitioning of the total ITF transport through each of the major outflow passage varies according to the phase of the Indian Ocean Dipole (IOD) or El Niño-Southern Oscillation (ENSO). In general, Pacific ENSO variability is strongest in Timor Passage, most likely through the influence of planetary waves transmitted from the Pacific along the Northwest Australian shelf pathway. Somewhat surprisingly, concurrent El Niño and positive IOD episodes consistently show contradictory results from those composites constructed for purely El Niño episodes. This is particularly evident in Lombok and Ombai Straits, but also at depth in Timor Passage. This suggests that Indian Ocean dynamics likely win out over Pacific Ocean dynamics in gating the transport through the outflow passages during concurrent ENSO and IOD events. Key Points A proxy 18 year Indonesian Throughflow (ITF) transport time series is developed Increased ITF transport related to enhanced Pacific tradewinds since early 1990s Indian Ocean dynamics dominate Pacific ENSO variability in ITF outflow passages © 2014. American Geophysical Union. All Rights Reserved.
Peglion F.,Institute Pasteur Paris |
Peglion F.,University Pierre and Marie Curie |
Llense F.,Institute Pasteur Paris |
Etienne-Manneville S.,Institute Pasteur Paris
Nature Cell Biology | Year: 2014
Collective cell migration is essential for both physiological and pathological processes. Adherens junctions (AJs) maintain the integrity of the migrating cell group and promote cell coordination while allowing cellular rearrangements. Here, we show that AJs undergo a continuous treadmilling along the lateral sides of adjacent leading cells. The treadmilling is driven by an actin-dependent rearward movement of AJs and is supported by the polarized recycling of N-cadherin. N-cadherin is mainly internalized at the cell rear and then recycled to the leading edge where it accumulates before being incorporated into forming AJs at the front of lateral cell-cell contacts. The polarized dynamics of AJs is controlled by a front-to-rear gradient of p120-catenin phosphorylation, which regulates polarized trafficking of N-cadherin. Perturbation of the GSK3-dependent phosphorylation of p120-catenin impacts on the stability of AJs, and the polarity and speed of leading cells during collective migration. © 2014 Macmillan Publishers Limited. All rights reserved.
Esling P.,University of Geneva |
Esling P.,University Pierre and Marie Curie |
Lejzerowicz F.,University of Geneva |
Pawlowski J.,University of Geneva
Nucleic Acids Research | Year: 2015
Tagging amplicons with tag sequences appended to PCR primers allow the multiplexing of numerous samples for high-throughput sequencing (HTS). This approach is routinely used in HTS-based diversity analyses, especially in microbial ecology and biomedical diagnostics. However, amplicon library preparation is subject to pervasive sample sequence cross-contaminations as a result of tag switching events referred to as mistagging. Here, we sequenced seven amplicon libraries prepared using various multiplexing designs in order to measure the magnitude of this phenomenon and its impact on diversity analyses. Up to 28.2% of the unique sequences correspond to undetectable (critical) mistags in single- or saturated double-tagging libraries. We show the advantage of multiplexing samples following Latin Square Designs in order to optimize the detection of mistags and maximize the information on their distribution across samples. We use this information in designs incorporating PCR replicates to filter the critical mistags and to recover the exact composition of mock community samples. Being parameter-free and data-driven, our approach can provide more accurate and reproducible HTS data sets, improving the reliability of their interpretations. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
Molodij G.,University Pierre and Marie Curie
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2011
A general expression of the spatial correlation functions of quantities related to the phase fluctuations of a wave that have propagated through the atmospheric turbulence are derived. A generalization of the method to integrand containing the product of an arbitrary number of hypergeometric functions is presented. The formalism is able to give the coefficients of phase-expansion functions orthogonal over an arbitrary circularly symmetric weighting function for an isotropic turbulence spectrum, as well as to describe the effect of the finite outer and inner scales of the turbulence and to describe the spherical propagation or to derive the effects of the analytical operators acting on the phase such as the derivatives of any order. The derivation of the generalized integrals with multiparameters is based on the Mellin transforms integration method. © 2011 Optical Society of America.
Rocanin-Arjo A.,University Pierre and Marie Curie
Blood | Year: 2014
Thrombin, the major enzyme of the hemostatic system, is involved in biological processes associated with several human diseases. The capacity of a given individual to generate thrombin, called the thrombin generation potential (TGP), can be robustly measured in plasma and was shown to associate with thrombotic disorders. To investigate the genetic architecture underlying the interindividual TGP variability, we conducted a genome-wide association study in 2 discovery samples (N = 1967) phenotyped for 3 TGP biomarkers, the endogenous thrombin potential, the peak height, and the lag time, and replicated the main findings in 2 independent studies (N = 1254). We identified the ORM1 gene, coding for orosomucoid, as a novel locus associated with lag time variability, reflecting the initiation process of thrombin generation with a combined P value of P = 7.1 × 10(-15) for the lead single nucleotide polymorphism (SNP) (rs150611042). This SNP was also observed to associate with ORM1 expression in monocytes (P = 8.7 × 10(-10)) and macrophages (P = 3.2 × 10(-3)). In vitro functional experiments further demonstrated that supplementing normal plasma with increasing orosomucoid concentrations was associated with impaired thrombin generation. These results pave the way for novel mechanistic pathways and therapeutic perspectives in the etiology of thrombin-related disorders.
Munakata T.,Kyoto University |
Rosinberg M.L.,University Pierre and Marie Curie
Physical Review Letters | Year: 2014
Continuous feedback control of Langevin processes may be non-Markovian due to a time lag between the measurement and the control action. We show that this requires one to modify the basic relation between dissipation and time reversal and to include a contribution arising from the noncausal character of the reverse process. We then propose a new definition of the quantity measuring the irreversibility of a path in a nonequilibrium stationary state, which can also be regarded as the trajectory-dependent total entropy production. This leads to an extension of the second law, which takes a simple form in the long-time limit. As an illustration, we apply the general approach to linear systems that are both analytically tractable and experimentally relevant. © 2014 American Physical Society.
De Medici L.,University Pierre and Marie Curie |
De Medici L.,University Paris - Sud |
De Medici L.,European Synchrotron Radiation Facility |
Giovannetti G.,International School for Advanced Studies |
Capone M.,International School for Advanced Studies
Physical Review Letters | Year: 2014
We show that electron- and hole-doped BaFe2As2 are strongly influenced by a Mott insulator that would be realized for half-filled conduction bands. Experiments show that weakly and strongly correlated conduction electrons coexist in much of the phase diagram, a differentiation which increases with hole doping. This selective Mottness is caused by the Hund's coupling effect of decoupling the charge excitations in different orbitals. Each orbital then behaves as a single-band doped Mott insulator, where the correlation degree mainly depends on how doped is each orbital from half filling. Our scenario reconciles contrasting evidences on the electronic correlation strength, implies a strong asymmetry between hole and electron doping, and establishes a deep connection with the cuprates. © 2014 American Physical Society.
MacAlpine D.M.,Duke University |
Almouzni G.,University Pierre and Marie Curie
Cold Spring Harbor Perspectives in Biology | Year: 2013
The size of a eukaryotic genome presents a unique challenge to the cell: package and organize the DNA to fit within the confines of the nucleus while at the same time ensuring sufficient dynamics to allow access to specific sequences and features such as genes and regulatory elements. This is achieved via the dynamic nucleoprotein organization of eukary-otic DNA into chromatin. The basic unit of chromatin, the nucleosome,comprises a core particle with 147 bp of DNA wrapped 1.7 times around an octamer of histones. The nucle-osome is a highly versatile and modular structure, both in its composition, with the existence of various histone variants, and through the addition of a series of posttranslational modifications on the histones. This versatility allows for both short-term regulatory responses to external signaling, as well as the long-term and multigenerational definition of large functional chromosomal domains within the nucleus, such as the centromere. Chromatin organization and its dynamics participate in essentially all DNA-templated processes, including transcription, replication, recombination, and repair. Here we will focus mainly on nucleo-somal organization and describe the pathways and mechanisms that contribute to assembly of this organization and the role of chromatin in regulating the DNA replication program. © 2013 Cold Spring Harbor Laboratory Press; all rights reserved.
Almouzni G.,University Pierre and Marie Curie
Nucleus (Austin, Tex.) | Year: 2011
Defined as a chromatin structure that remains condensed throughout the cell cycle heterochromatin is generally transcriptionally silent and is characterized by a specific molecular signature. Constitutive heterochromatin at the pericentromere is a conserved feature throughout evolution, which impacts genome stability. Here, we will summarize recent advances in our understanding of the dynamics of mouse pericentric heterochromatin during the cell cycle and development. Comparison with heterochromatin maintenance in fission yeast will enable discussions of the common basic principles and various mechanisms exploited in the distinct organisms.
Gabriel P.,University Pierre and Marie Curie
Mathematical and Computer Modelling | Year: 2011
We consider a polymerization (fragmentation) model with size-dependent parameters involved in prion proliferation. Using power laws for the different rates of this model, we recover the shape of the polymerization rate using experimental data. The technique used is inspired from , where the fragmentation dependence on prion strains is investigated. Our improvement is to use power laws for the rates, whereas  used a constant polymerization coefficient and linear fragmentation. © 2010 Elsevier Ltd.
Effects on outcomes of heart rate reduction by ivabradine in patients with congestive heart failure: Is there an influence of beta-blocker dose?: Findings from the SHIFT (Systolic Heart failure treatment with the I f inhibitor ivabradine Trial) study
Swedberg K.,Gothenburg University |
Komajda M.,University Pierre and Marie Curie |
Bohm M.,Universitatskliniken des Saarlandes |
Borer J.,New York University |
And 3 more authors.
Journal of the American College of Cardiology | Year: 2012
Objectives: This study used the SHIFT (Systolic Heart failure treatment with the I f inhibitor ivabradine Trial) database to assess the impact of background beta-blocker dose on response to ivabradine. Background: In systolic heart failure, reduction in relatively high heart rates improves clinical outcomes when achieved with beta-blockers and even more so when the sinus node inhibitor ivabradine also is added. Methods: Among patients with systolic heart failure, sinus rhythm, and heart rate <70 beats/min on recommended background therapy, maximally tolerated beta-blocker doses were subgrouped as no beta-blocker, <25%, 25% to <50%, 50% to <100%, and 100% of European Society of Cardiology-suggested target doses. The impact of ivabradine on cardiovascular death or heart failure hospitalization (primary endpoint) was analyzed in each subgroup as time-to-first event using Cox models adjusted for heart rate. The statistical models assessed heterogeneity and trend of the treatment effect across subgroups, and an additional analysis was made adjusting for the interaction of randomized treatment with baseline heart rate. Results: The primary endpoint and heart failure hospitalizations were significantly reduced by ivabradine in all subgroups with <50% of target beta-blocker dose, including no beta-blocker (p = 0.012). Despite an apparent trend to reduction in treatment-effect magnitude with increasing beta-blocker dose, no variation in treatment effect was seen in general heterogeneity interaction tests (p = 0.35). Across beta-blocker subgroups, treatment effect was borderline nonsignificant only for the primary endpoint (p = 0.056), and significance was further lost after adjusting for interaction between baseline heart rate and ivabradine effect (p = 0.14). Conclusions: The magnitude of heart rate reduction by beta-blocker plus ivabradine, rather than background beta-blocker dose, primarily determines subsequent effect on outcomes. (Effects of ivabradine on cardiovascular events in patients with moderate to severe chronic heart failure and left ventricular systolic dysfunction. A three-year randomised double-blind placebo-controlled international multicentre study; ISRCTN70429960) © 2012 American College of Cardiology Foundation.
Ribeiro P.,University of Lisbon |
Mosseri R.,University Pierre and Marie Curie
Physical Review Letters | Year: 2011
We discuss the entanglement properties of symmetric states of n qubits. The Majorana representation maps a generic such state into a system of n points on a sphere. Entanglement invariants, either under local unitaries (LU) or stochastic local operations and classical communication (SLOCC), can then be addressed in terms of the relative positions of the Majorana points. In the LU case, an overcomplete set of invariants can be built from the inner product of the radial vectors pointing to these points; this is detailed for the well-documented three-qubits case. In the SLOCC case, a cross ratio of related Möbius transformations are shown to play a central role, exemplified here for four qubits. Finally, as a side result, we also analyze the manifold of maximally entangled 3 qubit state, both in the symmetric and generic case. © 2011 American Physical Society.
Maeda Y.T.,Rockefeller University |
Buguin A.,University Pierre and Marie Curie |
Libchaber A.,Rockefeller University
Physical Review Letters | Year: 2011
Thermophoresis, the Soret effect, depletes a high concentration of a polyethylene glycol polymer solution from the hot region and builds a concentration gradient. In such a solution, solutes of small concentration experience thermophoresis and polyethylene glycol concentration-dependent restoring forces. We report that by using focused laser heating and varying the polyethylene glycol concentration one observes geometrical localizations of solutes like DNA and RNA into patterns such as a ring. For DNA up to 5.6 kbp, the ring size decreases following a behavior analogous to a gel electrophoresis separation. Above 5.6 kbp, the ring diameter increases with the DNA length. Mixtures of DNA and RNA can be separated as well as different RNA lengths. Separation of colloids is also observed. The experiments might be relevant for the separation of small RNA ribozymes in an early stage of life. © 2011 American Physical Society.
Despres B.,University Pierre and Marie Curie
Computer Methods in Applied Mechanics and Engineering | Year: 2010
We study the consistency in the weak sense of the cell-centered Lagrangian scheme GLACE. The main result is that GLACE is weakly consistent on general meshes in any dimension. The proof relies on a new formula for some geometric vectors defined at the corners of the cell, and which are basic Lagrangian objects. It validates theoretically the use of isoparametric elements (based on Q1 integration) for 3D Lagrangian compressible gas dynamics calculations. Finally we give the result of a simple convergence test in 2D. © 2010 Elsevier B.V.
Ducloue B.,University Paris - Sud |
Szymanowski L.,National Center for Nuclear Research |
Wallon S.,University Paris - Sud |
Wallon S.,University Pierre and Marie Curie
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014
We study effects related to violation of energy-momentum conservation inherent to the BFKL approach, in the particular case of Mueller-Navelet jets production. We argue, based on the comparison of the lowest order non-trivial corrections O(αs3) to the cross section with predictions of an exact calculation, that the inclusion of next-to-leading order BFKL corrections to the jet production vertex significantly reduces the importance of these effects. © 2014 The Authors.
Raynaud J.-P.,University Pierre and Marie Curie |
Rollet J.,Institute Rhone Alpin |
Legros J.-J.,University of Liege
BJU International | Year: 2013
What's known on the subject? and What does the study add? • Hypogonadism affects an estimated 2-4 million men in the USA, but only 5% receive treatment. Testosterone replacement therapy reduces the effects of testosterone deficiency on sexual function, mood and energy in hypogonadal patients. Long-term hypogonadism management requires testosterone treatment to restore serum concentrations of testosterone and its active metabolites, within physiological ranges; a testosterone preparation that achieves physiological plasma concentrations without supra-physiological escape is a preferred option. A previous 1-year study European clinical study showed the efficacy and safety of a transdermal testosterone patch (Testopatch®). • The present study shows the long-term (6-year) safety and efficacy of Testopatch in patients with primary or secondary hypogonadism. We show that, over the long-term, Testopatch was associated with no relevant changes in PSA concentration and PSA velocity, or any significant prostate risks (there were no cases of prostate cancer). Objective: • To assess the change in prostate-specific antigen (PSA) concentrations in patients with primary or secondary hypogonadism, receiving transdermal testosterone. Patients and Methods: • This was an interventional, 6-year study, conducted in Urology and Endocrinology centres in Belgium, France, Germany, the Netherlands and Spain. • Participants were primary (48%) or secondary (52%) hypogonadal patients who received two 60 cm2 testosterone patches (Testopatch®), delivering 4.8 mg of testosterone per day, applied every 2 days. • During treatment, total testosterone (TT), dihydrotestosterone, oestradiol and, PSA concentrations were measured in a centralised laboratory every 3 months during the first year, and every 6 months thereafter. Results: • In all, 200 patients [mean (sd) age 41.0 (12.5) years, body weight 82.5 (13.7) kg, height 177.2 (9.3) cm, body mass index 26.2 (3.4) kg/m2] were treated with transdermal testosterone patches. • In all, 161 patients completed the 1-year study and 115 entered into a 5-year study extension; 51 patients completed the sixth year of the study. • The mean baseline concentrations of TT and PSA were 1.4 ng/mL and 0.47 ng/mL, respectively; TT serum concentrations >3 ng/mL were achieved in 85% of patients and fluctuated between 4.4 and 6.0 ng/mL. • At each successive 6-month time point, mean the PSA values were 0.60, 0.67, 0.76, 0.70, 0.61, 0.68, 0.64, 0.71, 0.75, 0.74, 1.01, 0.78, 0.80 ng/mL, respectively. The mean PSA velocity was negligible (0.00-0.03 ng/mL/year) from 30 months to the end of the trial, except for a value of 0.08 at 60 months. Seven patients had a PSA concentration of >4 ng/mL due to a sharp PSA increase. Six of these patients had prostatitis and PSA concentrations returned to previous levels with appropriate treatment. No prostate cancer was reported during the trial. Conclusion: • These data support a strong safety profile for Testopatch, even at the highest registered dosage. © 2013 BJU International.
Cairon O.,British Petroleum |
Guesmi H.,University Pierre and Marie Curie
Physical Chemistry Chemical Physics | Year: 2011
Reliable experimental IR and theoretical approaches, both investigating CO adsorption on NaY faujasites, are supporting that CO capture occurs through the completion of the vacant coordination of Na+ cations located in the accessible SII sites. As a result, carbonyl adsorbed species are formed by the capture of one, two or three CO molecules and are experimentally discernable by their respective IR positions that are down-shifted by an average 11-12 cm-1 value for each captured CO molecule. DFT analysis is proposed for comparison and reproduces well the observed experimental shift of the νCO positions of the different polycarbonyls of interest. In addition, the effect of Si or Al composition surrounding the SII Na+ cation is investigated and results suggest that polycarbonyls that are formed might be in connection with the acidic strength of the cationic sites. This combined study completes and improves the understanding of the complex issue of CO adsorption at 80 K widely used as a model to explain how physical adsorption takes place in NaY faujasites working as an efficient industrial adsorbent in gas separation or gas purification processes. © the Owner Societies.
Letessier-Selvon A.,University Pierre and Marie Curie
Brazilian Journal of Physics | Year: 2014
The Pierre Auger Observatory is the world’s largest cosmic ray observatory. Our current exposure reaches nearly 40,000 km2sr and provides us with an unprecedented quality data set. The performance and stability of the detectors and their enhancements are described. Data analyses have led to a number of major breakthroughs. Among these, we discuss the energy spectrum and the searches for large-scale anisotropies. We present analyses of our Xmax data and show how it can be interpreted in terms of mass composition. We also describe some new analyses that extract mass-sensitive parameters from the 100 % duty cycle surface detector (SD) data. A coherent interpretation of all these recent results opens new directions. The consequences regarding the cosmic ray composition and the properties of ultrahigh-energy cosmic ray (UHECR) sources are briefly discussed. © 2014, Sociedade Brasileira de Física.
Halmagyi N.,University Pierre and Marie Curie
Journal of High Energy Physics | Year: 2014
We study static BPS black hole horizons in four dimensional N = 2 gauged supergravity coupled to nv -vector multiplets and with an arbitrary cubic prepotential. We work in a symplectically covariant formalism which allows for both electric and magnetic gauging parameters as well as dyonic background charges and obtain the general solution to the BPS equations for horizons of the form AdS2 × Σg . In particular this means we solve for the scalar fields as well as the metric of these black holes as a function of the gauging parameters and background charges. When the special Kähler manifold is a symmetric space, our solution is completely explicit and the entropy is related to the familiar quartic invariant. For more general models our solution is implicit up to a set of holomorphic quadratic equations. For particular models which have known embeddings in M-theory, we derive new horizon geometries with dyonic charges and numerically construct black hole solutions. These correspond to M2-branes wrapped on a Riemann surface in a local Calabi-Yau five-fold with internal spin.©The Authors.
Shields C.J.,Materials Misericordiae University Hospital |
Tiret E.,University Pierre and Marie Curie |
Winter D.C.,St Vincents University Hospital
Annals of Surgery | Year: 2010
Objective: This study aims to describe recent experience with rectal carcinoids in European and North American centers. Background: While considered indolent, the propensity of carcinoids to metastasize can be significant. Methods: Rectal carcinoid patients were identified from prospective databases maintained at 9 institutions between 1999 and 2008. Demographic, clinical, and histologic data were collated. Median follow-up was 5 years (range, 0.5-10 years). Results: Two hundred two patients were identified. The median age was 55 years (range, 31-81 years). The majority of tumors were an incidental finding (n = 115, 56.9%). The median tumor size was 10 mm (range, 2-120 mm). Overall, 93 (49%) tumors were limited to the mucosa or submucosa, 45 (24%) involved the muscularis propria, 29 (15%) extended into the perirectal fat, and 6 (3%) reached the visceral peritoneum. The primary treatment modalities were endoscopic resection (n = 86, 43%) and surgical extirpation (n = 102, 50%). Forty-one patients (40%) underwent a high anterior resection, whereas 45 (44%) underwent anterior resection with total mesorectal excision. Seven patients (7%) underwent Hartman's procedure, 7 (7%) underwent abdomino-perineal resection, and 6 (6%) had transanal endoscopic microsurgery, whereas 4 (4%) patients underwent a transanal excision. Multiple variable logistic regression analysis demonstrated that tumor size greater than 10 mm and lymphovascular invasion were predictors of nodal involvement (P = 0.006 and < 0.001, respectively), whereas the presence of lymph node metastases and lymphovascular invasion was associated with subsequent development of distant metastases (P = 0.033 and 0.022, respectively). The presence of nodal metastases has a profound effect upon survival, with a 5-year survival rate of 70%, and 10-year survival of 60% for node positive tumors. Patients with distant metastases have a 4-year survival of 38%. Conclusion: Tumor size greater than 10 mm and lymphovascular invasion are significantly associated with the presence of nodal disease, rendering mesorectal excision advisable. Transanal excision is adequate for smaller tumors. Copyright © 2010 by Lippincott Williams & Wilkins.
Ojala M.,Aalto University |
Garriga G.C.,University Pierre and Marie Curie
Journal of Machine Learning Research | Year: 2010
We explore the framework of permutation-based p-values for assessing the performance of classifiers. In this paper we study two simple permutation tests. The first test assess whether the classifier has found a real class structure in the data; the corresponding null distribution is estimated by permuting the labels in the data. This test has been used extensively in classification problems in computational biology. The second test studies whether the classifier is exploiting the dependency between the features in classification; the corresponding null distribution is estimated by permuting the features within classes, inspired by restricted randomization techniques traditionally used in statistics. This new test can serve to identify descriptive features which can be valuable information in improving the classifier performance. We study the properties of these tests and present an extensive empirical evaluation on real and synthetic data. Our analysis shows that studying the classifier performance via permutation tests is effective. In particular, the restricted permutation test clearly reveals whether the classifier exploits the interdependency between the features in the data. © 2010 Markus Ojala and Gemma C. Garriga.
Mukhopadhyay A.,University Pierre and Marie Curie
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013
We derive a nonequilibrium fluctuation-dissipation relation for bosonic correlation functions from holography in the classical gravity approximation at strong coupling. This generalizes the familiar thermal fluctuation-dissipation relation in the absence of external sources. This also holds universally for any nonequilibrium state which can be obtained from a stable thermal equilibrium state in perturbative derivative (hydrodynamic) and amplitude (nonhydrodynamic) expansions. Therefore, this can provide a strong experimental test for the applicability of the holographic framework. We discuss how it can be tested in heavy-ion collisions. We also make a conjecture regarding multipoint holographic nonequilibrium Green's functions. © 2013 American Physical Society.
Galoisy L.,University Pierre and Marie Curie
Elements | Year: 2013
Garnet often occurs as naturally multifaceted, brightly colored, transparent, single crystals. These crystals represent chemically diverse solid solutions with a remarkable range of colors, which are largely controlled by the crystal chemistry of transition elements such as Fe, Mn, Ti, Cr, and V. These same optical properties have given garnet important cultural and historical relevance as a sought-after gemstone, from biblical times to the present day. © DECEMBER 2013.
Dubuisson S.,University Pierre and Marie Curie
Pattern Recognition Letters | Year: 2011
In this paper we present a new method for fast histogram computing and its extension to bin to bin histogram distance computing. The idea consists in using the information of spatial differences between images, or between regions of images (a current one and a reference one), and encoding it into a specific data structure: a tree. The histogram of the current image or of one of its regions is then computed by updating the histogram of the reference one using the temporal data stocked into the tree. With this approach, we never need to store any of the current histograms, except the reference image ones, as a preprocessing step. We compare our approach with the well-known Integral Histogram one, and obtain better results in terms of processing time while reducing the memory footprint. We show theoretically and with experimental results the superiority of our approach in many cases. We also extend our idea to the computation of the Bhattacharyya distance between two histograms, using a similar incremental approach that also avoid current histogram computations: we just need histograms of the reference image, and spatial differences between the reference and the current image to compute this distance using an updating process. Finally, we demonstrate the advantages of our approach on a real visual tracking application using a particle filter framework by improving its correction step computation time. © 2010 Elsevier B.V. All rights reserved.
Christin-Maitre S.,University Pierre and Marie Curie |
Christin-Maitre S.,French Institute of Health and Medical Research
Best Practice and Research: Clinical Endocrinology and Metabolism | Year: 2013
The first hormonal pill, called Enovid®, was approved by the Federal Drug Administration (FDA) in May 1960. It contained mestranol and norethisterone. Over the years, oral contraceptives have evolved through gradual lowering of ethinyl estradiol (EE) content, introduction of 17β estradiol, and many different progestins. The standard regimen allows for 21 days of pill containing steroids and a pill-free interval of 7 days. Recently, continuous or extended regimens have been approved. In order to improve compliance, alternative routes of combined oral contraceptive (COC) administration have been developed such as vaginal or transdermal routes. In 2009, according to the United Nations, the mean global percentage using contraception in women who are married or in union was 62.7%. COC represented 8.8% of contraceptive prevalence, reaching 15.4% in more developed countries. More than 100 million women worldwide use COCs. However, each year, many unintended pregnancies occur, indicating that contraception still needs to be promoted. © 2012 Elsevier Ltd. All rights reserved.
Brezillon P.,University Pierre and Marie Curie
Knowledge Engineering Review | Year: 2011
This paper presents a personal interpretation of the evolution of artificial intelligence (AI) systems during these last 25 years. This evolution is presented along five generations of AI systems, namely expert systems, joint cognitive systems, intelligent systems, intelligent assistant systems, and the coming generation of context-based intelligent assistant systems. Our testimony relies on different real-world applications in different domains, especially for the French national power company, the subway companies in Paris and in Rio de Janeiro, in medicine, a platform for e-maintenance, road safety, and open sources. Our main claim is to underline that the next generation of AI systems (context-based intelligent assistant systems) requires a radically different consideration on context and its relations with the users, the task at hand, the situation, and the environment in which the task is accomplish by the user; the observation of users through their behaviors and not a profile library; a robust conceptual framework for modeling and managing context; and a computational tool for representing in a uniform way pieces of knowledge, of reasoning, and of contexts. © Cambridge University Press, 2011.
Zenginoglu A.,University Pierre and Marie Curie |
Zenginoglu A.,California Institute of Technology
Journal of Computational Physics | Year: 2011
We show how to solve hyperbolic equations numerically on unbounded domains by compactification, thereby avoiding the introduction of an artificial outer boundary. The essential ingredient is a suitable transformation of the time coordinate in combination with spatial compactification. We construct a new layer method based on this idea, called the hyperboloidal layer. The method is demonstrated on numerical tests including the one dimensional Maxwell equations using finite differences and the three dimensional wave equation with and without nonlinear source terms using spectral techniques. © 2010 Elsevier Inc.
Lorenceau J.,University Pierre and Marie Curie
Current Biology | Year: 2012
The eyes never cease to move: ballistic saccades quickly turn the gaze toward peripheral targets, whereas smooth pursuit maintains moving targets on the fovea where visual acuity is best. Despite the oculomotor system being endowed with exquisite motor abilities, any attempt to generate smooth eye movements against a static background results in saccadic eye movements [1, 2]. Although exceptions to this rule have been reported [3-5], volitional control over smooth eye movements is at best rudimentary. Here, I introduce a novel, temporally modulated visual display, which, although static, sustains smooth eye movements in arbitrary directions. After brief training, participants gain volitional control over smooth pursuit eye movements and can generate digits, letters, words, or drawings at will. For persons deprived of limb movement, this offers a fast, creative, and personal means of linguistic and emotional expression. © 2012 Elsevier Ltd All rights reserved.
Indelicato P.,University Pierre and Marie Curie
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013
The largest contributions to the n=2 Lamb shift, fine structure interval and 2s hyperfine structure of muonic hydrogen are calculated by accurate numerical evaluations of the Dirac equation rather than by a perturbation expansion in powers of 1/c, in the framework of nonrelativistic quantum electrodynamics. Previous calculations and the validity of the perturbation expansion for light elements are confirmed. The dependence of the various effects on the nuclear size and model are studied. © 2013 American Physical Society.
Reinosa U.,Ecole Polytechnique - Palaiseau |
Serreau J.,CNRS Astroparticle and Cosmology Lab |
Tissier M.,University Pierre and Marie Curie
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015
We investigate the phase diagram of QCD with heavy quarks at finite temperature and chemical potential in the context of background field methods. In particular, we use a massive extension of the Landau-DeWitt gauge which is motivated by previous studies of the deconfinement phase transition in pure Yang-Mills theories. We show that a simple one-loop calculation is able to capture the richness of the phase diagram in the heavy quark region, both at real and imaginary chemical potential. Moreover, dimensionless ratios of quantities directly measurable in numerical simulations are in good agreement with lattice results. © 2015 American Physical Society.
Hurbain I.,University Pierre and Marie Curie |
Sachse M.,Institute Pasteur Paris
Biology of the Cell | Year: 2011
Our knowledge of the organization of the cell is linked, to a great extent, to light and electron microscopy. Choosing either photons or electrons for imaging has many consequences on the image obtained, as well as on the experiment required in order to generate the image. One apparent effect on the experimental side is in the sample preparation, which can be quite elaborate for electron microscopy. In recent years, rapid freezing, cryo-preparation and cryo-electron microscopy have been more widely used because they introduce fewer artefacts during preparation when compared with chemical fixation and room temperature processing. In addition, cryo-electron microscopy allows the visualization of the hydrated specimens. In the present review, we give an introduction to the rapid freezing of biological samples and describe the preparation steps. We focus on bulk samples that are too big to be directly viewed under the electron microscope. Furthermore, we discuss the advantages and limitations of freeze substitution and cryo-electron microscopy of vitreous sections and compare their application to the study of bacteria and mammalian cells and to tomography. © The Authors Journal compilation © 2011 Portland Press Limited.
Decaudin D.,Laboratory of Preclinical Investigation |
Decaudin D.,University Pierre and Marie Curie
Anti-Cancer Drugs | Year: 2011
The treatment of cancer is continually improving as a result of a better understanding of oncogenesis and the development of new targeted compounds. Early clinical trials evaluating such candidate compounds require a large number of patients, and are expensive, time consuming, and expose patients to certain risks. To select the most effective molecules, preclinical investigation of antitumor compounds is an important step in the drug development process. Three main categories of preclinical cancer models are generally used in preclinical investigations, namely genetically engineered models, xenografts derived from human tumor cell lines, and human tumor fragments from patients implanted directly into immunodeficient mice, known as tumorgrafts. The establishment of tumorgrafts constitutes a long-term process consisting of various steps, in which the final objective is to show that the validated model accurately reproduces human cancer, with a high predictive value of therapeutic efficacy (regardless of the type of treatment), and closely mimics clinical situations frequently observed in patients with cancer, such as resistance to standard treatments, metastases, and relapse after initial therapies (involving residual tumor-initiating cells). The aim of this study is therefore to discuss the proposed criteria for the establishment and validation of preclinical models of human cancers that should be used for further pharmacological assessments. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Benichou O.,CNRS Condensed Matter Physics Laboratory |
Voituriez R.,CNRS Condensed Matter Physics Laboratory |
Voituriez R.,University Pierre and Marie Curie
Physics Reports | Year: 2014
We present a general theory which allows one to accurately evaluate the mean first-passage time (FPT) for regular random walks in bounded domains, and its extensions to related first-passage observables such as splitting probabilities and occupation times. It is showed that this analytical approach provides a universal scaling dependence of the mean FPT on both the volume of the confining domain and the source-target distance in the case of general scale invariant processes. This analysis is applicable to a broad range of stochastic processes characterized by scale-invariance properties. The full distribution of the FPT can be obtained using similar tools, and displays universal features. This allows to quantify the fluctuations of the FPT in confinement, and to reveal the key role that can be played by the starting position of the random walker. Applications to reaction kinetics in confinement are discussed. © 2014 Elsevier B.V.