70 results on '"C. Bena"'
Search Results
2. Sublattice dependence and gate-tunability of midgap and resonant states induced by native dopants in Bernal-stacked bilayer graphene
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François Ducastelle, Eberth A. Quezada-Lopez, Jairo Velasco, C. Bena, Frédéric Joucken, Zhehao Ge, Kenji Watanabe, Takashi Tanagushi, University of California [Santa Cruz] (UCSC), University of California, Arizona State University [Tempe] (ASU), Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), LEM, UMR 104, CNRS-ONERA, Université Paris-Saclay (Laboratoire d'étude des microstructures), ONERA-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), DMAS, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, National Institute for Materials Science (NIMS), J. V. J. acknowledges support from the National Science Foundation under Grant No. DMR-1753367 and the Army Research Office under Contract No. W911NF-17-1-0473. K. W. and T. T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan, Grant No. JPMXP0112101001 and JSPS KAKENHI Grant No. JP20H00354., University of California [Santa Cruz] (UC Santa Cruz), University of California (UC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,Band gap ,FOS: Physical sciences ,General Physics and Astronomy ,Tight-binding model ,02 engineering and technology ,Local density of states ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,[SPI]Engineering Sciences [physics] ,Tight binding ,Dopants ,law ,Condensed Matter::Superconductivity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,[CHIM]Chemical Sciences ,010306 general physics ,Scanning tunneling microscopy ,[PHYS]Physics [physics] ,Condensed Matter - Materials Science ,Valence (chemistry) ,Condensed matter physics ,Dopant ,Condensed Matter - Mesoscale and Nanoscale Physics ,Graphene ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,3. Good health ,Scanning tunneling microscope ,0210 nano-technology ,Bilayer graphene - Abstract
The properties of semiconductors can be crucially impacted by midgap states induced by dopants, which can be native or intentionally incorporated in the crystal lattice. For Bernal-stacked bilayer graphene (BLG), which has a tunable bandgap, the existence of midgap states induced by dopants has been conjectured, but never confirmed experimentally. Here, we report scanning tunneling microscopy and spectroscopy results, supported by tight-binding calculations, that demonstrate the existence of midgap states in BLG. We show that the midgap state in BLG -- for which we demonstrate gate-tunability -- appears when the dopant is hosted on the non-dimer sublattice sites. We further evidence the presence of narrow resonances at the onset of the high energy bands (valence or conduction, depending on the dopant type) when the dopants lie on the dimer sublattice sites. These results suggest that dopants/defects can play an important role in the transport and optical properties of multilayer graphene samples, especially at energies close to the band extrema., Includes supplementary material
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- 2021
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3. Analytical and semianalytical tools to determine the topological character of Shiba chains
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Nicholas Sedlmayr, Vardan Kaladzhyan, and C. Bena
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Superconductivity ,Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Superconductivity ,Numerical analysis ,FOS: Physical sciences ,Function (mathematics) ,Topology ,Superconductivity (cond-mat.supr-con) ,Character (mathematics) ,Chain (algebraic topology) ,Impurity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Phase diagram ,Magnetic impurity - Abstract
We introduce three new analytical and semi-analytical tools that allow one to determine the topological character of impurity Shiba chains. The analytical methods are based on calculating the effective Green's function of an infinite embedded chain using the T-matrix formalism and describing the chain as a {\it line impurity}. We thus provide a solution to the longstanding size-effects problem affecting the only general alternative method, the numerical tight-binding analysis. As an example we consider a chain of magnetic impurities deposited on an s-wave superconducting substrate with Rashba spin-orbit and we calculate its topological phase diagram as a function of the magnetic impurity strength and the chemical potential. We find a perfect agreement between all our new techniques and a numerical analysis.
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- 2021
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4. Effects of dietary free fatty acid content and degree of fat saturation on tibia bone properties of laying hens
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M. Palomar, M.D. Soler, C. Benavides-Reyes, A.B. Rodríguez-Navarro, J.A. García-Bautista, A. Orozco, and C. Garcés-Narro
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acid oil ,bone quality ,calcium ,fat by-product ,fatty acid distillate ,Animal culture ,SF1-1100 - Abstract
ABSTRACT: Acid oils and fatty acid distillates are fat by-products of the refining process of edible oils and are characterized by their high proportion of free fatty acids (FFA). While lipids are essential in poultry diets, their chemical structure may interfere with calcium absorption. Therefore, this study investigated the effects of dietary FFA content and the degree of fat saturation on bone metabolism in commercial layers. For 15-wk, a total of 144 laying hens (19-wk-old) were randomly assigned to 8 treatments (6 replicates with 3 birds each), which were obtained by gradually replacing crude soybean oil (rich in unsaturated fatty acids [UFA]) with soybean acid oil (rich in UFA and FFA), or crude palm oil (rich in saturated fatty acids [SFA]) with palm fatty acid distillate (rich in SFA and FFA). Following a 2 × 4 factorial design, 4 UFA-rich and 4 SFA-rich diets were created with varying FFA content: 10, 20, 30, and 45%. Tibiae (6 birds/treatment) were collected at the end of the trial for the assessment of mineral composition, morphological properties, and mechanical characteristics. The data were analyzed using a 2-way ANOVA with the GLM procedure. Orthogonal polynomial contrasts were employed to determine the linear effect of increasing %FFA, with statistical significance set at P < 0.05. The degree of saturation was found to negatively impact on calcium and phosphorus bone content, with higher levels found in soybean-based diets (P < 0.001). A significant interaction was observed for medullary bone mineral content, showing a linear decrease as the dietary %FFA increased (P < 0.05) in palm diets. In contrast, morphological and mechanical bone traits, total ash content, and cortical bone mineral composition remained unaffected (P > 0.05). These results suggest that the degree of fat saturation exerts a greater impact than FFA content on bone mineral metabolism, supporting the commercial use of fat by-products rich in FFA in laying hen diets, at least during the early stages of the laying cycle.
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- 2024
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5. Direct Visualization of Native Defects in Graphite and Their Effect on the Electronic Properties of Bernal-Stacked Bilayer Graphene
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C. Bena, Sarah Pinon, Frédéric Joucken, Zhehao Ge, Takashi Taniguchi, Vardan Kaladzhyan, Jairo Velasco, Eberth A. Quezada-Lopez, Kenji Watanabe, and Aires Ferreira
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Materials science ,FOS: Physical sciences ,Bioengineering ,02 engineering and technology ,01 natural sciences ,law.invention ,law ,Microscopy, Scanning Tunneling ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,General Materials Science ,Graphite ,010306 general physics ,Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics ,Dopant ,Scattering ,Graphene ,Mechanical Engineering ,Materials Science (cond-mat.mtrl-sci) ,Heterojunction ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Boltzmann equation ,Chemical physics ,Scanning tunneling microscope ,Electronics ,0210 nano-technology ,Bilayer graphene - Abstract
Graphite crystals used to prepare graphene-based heterostructures are generally assumed to be defect free. We report here scanning tunneling microscopy results that show graphite commonly used to prepare graphene devices can contain a significant amount of native defects. Extensive scanning of the surface allows us to determine the concentration of native defects to be 6.6$\times$10$^8$ cm$^{-2}$. We further study the effects of these native defects on the electronic properties of Bernal-stacked bilayer graphene. We observe gate-dependent intravalley scattering and successfully compare our experimental results to T-matrix-based calculations, revealing a clear carrier density dependence in the distribution of the scattering vectors. We also present a technique for evaluating the spatial distribution of short-scale scattering. A theoretical analysis based on the Boltzmann transport equation predicts that the dilute native defects identified here are an important extrinsic source of scattering, ultimately setting the mobility at low temperatures., Comment: Accepted in Nano Letters
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- 2021
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6. Surface Green's functions and quasiparticle interference in Weyl semimetals
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Sarah Pinon, C. Bena, Vardan Kaladzhyan, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Royal Institute of Technology [Stockholm] (KTH ), and European Project: 679722,QuantMatt - Grant agreement ID: 679722
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Physics ,[PHYS]Physics [physics] ,Condensed Matter - Mesoscale and Nanoscale Physics ,Scattering ,FOS: Physical sciences ,Minimal models ,01 natural sciences ,Semimetal ,010305 fluids & plasmas ,Green S ,chemistry.chemical_compound ,chemistry ,Mesoscale and Nanoscale Physics ,Lattice (order) ,Quantum mechanics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Quasiparticle ,Density of states ,010306 general physics ,[PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall] ,Surface states - Abstract
We use the exact analytical technique introduced by us [Phys. Rev. B 101, 115405 (2020)] to recover the surface Green's functions and the corresponding Fermi-arc surface states for various lattice models of Weyl semimetals. For these models we use the $T$-matrix formalism to calculate the quasiparticle interference patterns generated in the presence of impurity scattering. In particular, we consider the models introduced by Kourtis et al. [Phys. Rev. B 93, 041109(R) (2016)] (model A) and Lau et al. [Phys. Rev. Lett. 119, 076801 (2017)] (model B), and we find that, as opposed to observations previously obtained via joint density of states and spin-dependent scattering probability, the interarc scattering in the quasiparticle interference features is fully suppressed in model A, and is very small in model B. Our findings indicate that these models may not correctly describe materials such as ${\mathrm{MoTe}}_{2}$, since for such materials interarc scattering is clearly visible experimentally, e.g., by Deng et al. [Nat. Phys. 12, 1105 (2016)]. We also focus on the minimal models proposed by McCormick et al. [Phys. Rev. B 95, 075133 (2017)], which indeed recover significant interarc scattering features.
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- 2020
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7. Obtaining Majorana and other boundary modes from the metamorphosis of impurity-induced states: Exact solutions via the T-matrix
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C. Bena, Vardan Kaladzhyan, Royal Institute of Technology [Stockholm] (KTH ), Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and European Project: 679722,QuantMatt - Grant agreement ID: 679722
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Physics ,T matrix ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Superconductivity ,FOS: Physical sciences ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Superconductivity (cond-mat.supr-con) ,MAJORANA ,Formalism (philosophy of mathematics) ,Impurity ,Quantum mechanics ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Edge states ,010306 general physics ,0210 nano-technology ,[PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall] ,Surface states - Abstract
We provide here a new and exact formalism to describe the formation of end, edge or surface states through the evolution of impurity-induced states. We propose a general algorithm that consists of finding the impurity states via the T-matrix formalism and showing that they evolve into boundary modes when the impurity potential goes to infinity. We apply this technique to obtain Majorana states in 1D and 2D systems described by the Kitaev model with point-like and respectively line-like impurities. We confirm our exact analytical results by a numerical tight-binding approach. We argue that our formalism can be applied to other topological models, as well as to any model exhibiting edge states., 5 pages, 5 figures
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- 2019
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8. Modeling long imperfect SNS junctions and Andreev bound states using two impurities and the T -matrix formalism
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Vardan Kaladzhyan, C. Bena, Sarah Pinon, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Royal Institute of Technology [Stockholm] (KTH ), and European Project: 679722,QuantMatt - Grant agreement ID: 679722
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[PHYS]Physics [physics] ,Physics ,T matrix ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Scattering ,FOS: Physical sciences ,02 engineering and technology ,Electron ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,Andreev reflection ,Formalism (philosophy of mathematics) ,Impurity ,Condensed Matter::Superconductivity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Bound state ,Imperfect ,010306 general physics ,0210 nano-technology ,[PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall] - Abstract
International audience; We provide a new analytical tool to calculate the energies of Andreev bound states (ABS) in long imperfect SNS junctions, at present these can only be described by numerical tools. We model an NS junction as a delta-function "Andreev" impurity, i.e., a localized potential which scatters an electron into a hole with opposite spin. We show using the scattering matrix formalism that, quite surprisingly, an "Andreev" impurity is equivalent to an NS junction characterized by both Andreev reflection and a finite amount of normal scattering. The ABS energies are then calculated using the T-matrix formalism applied to a system with two Andreev impurities. Our results lie between those for a perfect long SNS junction limit described by the Andreev approximation (ABS energies depend linearly on the phase and are independent of the chemical potential) and the particle-inthe-box limit (bound state energies are independent of the phase and have a linear dependence on the chemical potential). Moreover, we recover a closed-form expression for the ABS energies by expanding around the particle-in-the-box limit.
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- 2019
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9. Surface Green's functions and boundary modes using impurities: Weyl semimetals and topological insulators
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C. Bena, Sarah Pinon, Vardan Kaladzhyan, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Royal Institute of Technology [Stockholm] (KTH ), and European Project: 679722,ERC
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Physics ,Surface (mathematics) ,[PHYS]Physics [physics] ,Work (thermodynamics) ,Condensed Matter - Mesoscale and Nanoscale Physics ,Formalism (philosophy) ,Boundary (topology) ,FOS: Physical sciences ,Insulator (electricity) ,02 engineering and technology ,Function (mathematics) ,021001 nanoscience & nanotechnology ,01 natural sciences ,Semimetal ,Theoretical physics ,Topological insulator ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,010306 general physics ,0210 nano-technology - Abstract
In this work we provide a direct and non-numerical technique to obtain the surface Green's functions for three-dimensional systems. This technique is based on the ideas presented by V. Kaladzhyan and C. Bena [Phys. Rev. B 100, 081106(R) (2019)], in which we start with an infinite system and model the boundary using a planelike infinite-amplitude potential. Such a configuration can be solved exactly using the $T$-matrix formalism. We apply our method to calculate the surface Green's function and the corresponding Fermi-arc states for Weyl semimetals. We also apply the technique to systems of lower dimensions, such as Kane-Mele and Chern insulator models, to provide a more efficient and non-numerical method to describe the formation of edge states.
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- 2019
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10. IPD2.05 Effects of ivacaftor in patients with cystic fibrosis and severe lung disease carrying CFTR mutations with residual function
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Donatello Salvatore, Giovanna Pisi, C. Colangelo, G. Tuccio, Cesare Braggion, C. Bena, and B. Messore
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,business.industry ,05 social sciences ,medicine.disease ,Cystic fibrosis ,Gastroenterology ,Ivacaftor ,03 medical and health sciences ,0302 clinical medicine ,Lung disease ,Internal medicine ,0502 economics and business ,Pediatrics, Perinatology and Child Health ,medicine ,050211 marketing ,In patient ,business ,030217 neurology & neurosurgery ,medicine.drug - Published
- 2018
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11. Microglial diversity along the hippocampal longitudinal axis impacts synaptic plasticity in adult male mice under homeostatic conditions
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E. De Felice, E. Gonçalves de Andrade, M. T. Golia, F. González Ibáñez, M. Khakpour, M. A. Di Castro, S. Garofalo, E. Di Pietro, C. Benatti, N. Brunello, F. Tascedda, B. Kaminska, C. Limatola, D. Ragozzino, M. E. Tremblay, S. Alboni, and L. Maggi
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LTP ,Dorsal hippocampus ,Ventral hippocampus ,Microglial morphology ,Microglial ultrastructure ,CX3CL1–CX3CR1 signaling ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract The hippocampus is a plastic brain area that shows functional segregation along its longitudinal axis, reflected by a higher level of long-term potentiation (LTP) in the CA1 region of the dorsal hippocampus (DH) compared to the ventral hippocampus (VH), but the mechanisms underlying this difference remain elusive. Numerous studies have highlighted the importance of microglia–neuronal communication in modulating synaptic transmission and hippocampal plasticity, although its role in physiological contexts is still largely unknown. We characterized in depth the features of microglia in the two hippocampal poles and investigated their contribution to CA1 plasticity under physiological conditions. We unveiled the influence of microglia in differentially modulating the amplitude of LTP in the DH and VH, showing that minocycline or PLX5622 treatment reduced LTP amplitude in the DH, while increasing it in the VH. This was recapitulated in Cx3cr1 knockout mice, indicating that microglia have a key role in setting the conditions for plasticity processes in a region-specific manner, and that the CX3CL1–CX3CR1 pathway is a key element in determining the basal level of CA1 LTP in the two regions. The observed LTP differences at the two poles were associated with transcriptional changes in the expression of genes encoding for Il-1, Tnf-α, Il-6, and Bdnf, essential players of neuronal plasticity. Furthermore, microglia in the CA1 SR region showed an increase in soma and a more extensive arborization, an increased prevalence of immature lysosomes accompanied by an elevation in mRNA expression of phagocytic markers Mertk and Cd68 and a surge in the expression of microglial outward K+ currents in the VH compared to DH, suggesting a distinct basal phenotypic state of microglia across the two hippocampal poles. Overall, we characterized the molecular, morphological, ultrastructural, and functional profile of microglia at the two poles, suggesting that modifications in hippocampal subregions related to different microglial statuses can contribute to dissect the phenotypical aspects of many diseases in which microglia are known to be involved.
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- 2022
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12. Testing the formation of Majorana states using the Majorana Polarization
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C. Bena, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
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Edge state ,États de bord ,Majorana fermions ,Energy Engineering and Power Technology ,FOS: Physical sciences ,02 engineering and technology ,STRIPS ,01 natural sciences ,law.invention ,Superconductivity (cond-mat.supr-con) ,symbols.namesake ,Physics::Popular Physics ,law ,Quantum mechanics ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,010306 general physics ,Majorana equation ,Physics ,Superconductivity ,Zeeman effect ,Condensed Matter - Mesoscale and Nanoscale Physics ,Supraconducteurs topologiques ,Condensed Matter - Superconductivity ,High Energy Physics::Phenomenology ,General Engineering ,Topological superconductors ,021001 nanoscience & nanotechnology ,Polarization (waves) ,[PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph] ,Physics::History of Physics ,3. Good health ,Magnetic field ,[PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con] ,MAJORANA ,Fermions de Majorana ,symbols ,0210 nano-technology - Abstract
We study the formation of Majorana states in superconductors using the Majorana polarization, which can locally evaluate the Majorana character of a given state. We introduce the definition of the Majorana polarization vector and the corresponding criterion to identify a Majorana state, and we apply it to some simple cases such as a one-dimensional wire with spin-orbit coupling, subject to a Zeeman magnetic field, and proximitized by a superconductor, as well as to an NS junction made with such a wire. We also apply this criterion to two-dimensional finite-size strips and squares subject to the same physical conditions. Our analysis demonstrates the necessity of using the Majorana polarization local order parameter to characterize the Majorana states, particularly in finite-size systems., Comment: 16 pages, 11 figures, review article published in Comptes Rendus Physique
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- 2017
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13. Determining the spin-orbit coupling via spin-polarized spectroscopy of magnetic impurities
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Vardan Kaladzhyan, C. Bena, and Pascal Simon
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FOS: Physical sciences ,02 engineering and technology ,01 natural sciences ,law.invention ,Superconductivity (cond-mat.supr-con) ,law ,Condensed Matter::Superconductivity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,010306 general physics ,Spin-½ ,Physics ,Friedel oscillations ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed matter physics ,Magnetic moment ,Condensed Matter - Superconductivity ,Spin–orbit interaction ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,3. Good health ,Coupling (physics) ,Topological insulator ,Density of states ,Condensed Matter::Strongly Correlated Electrons ,Scanning tunneling microscope ,0210 nano-technology - Abstract
We study the spin-resolved spectral properties of the impurity states associated to the presence of magnetic impurities in two-dimensional, as well as one-dimensional systems with Rashba spin-orbit coupling. We focus on Shiba bound states in superconducting materials, as well as on impurity states in metallic systems. Using a combination of a numerical T-matrix approximation and a direct analytical calculation of the bound state wave function, we compute the local density of states (LDOS) together with its Fourier transform (FT). We find that the FT of the spin-polarized LDOS, a quantity accessible via spin-polarized STM, allows to accurately extract the strength of the spin-orbit coupling. Also we confirm that the presence of magnetic impurities is strictly necessary for such measurement, and that non-spin-polarized experiments cannot have access to the value of the spin-orbit coupling., 26 pages, 6 figures
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- 2016
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14. Majorana bound states in open quasi-one-dimensional and two-dimensional systems with transverse Rashba coupling
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Nicholas Sedlmayr, C. Bena, J. M. Aguiar-Hualde, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'étude des microstructures [Châtillon] (LEM - ONERA - CNRS), ONERA-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-ONERA, and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)
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Physics ,COUPLAGE ,Zeeman effect ,MAJORANA ,Condensed matter physics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,UNIDIMENSIONNEL ,Physics::History of Physics ,[SPI.MAT]Engineering Sciences [physics]/Materials ,symbols.namesake ,Quantum mechanics ,0103 physical sciences ,Bound state ,symbols ,SYMETRIE ,Boundary value problem ,010306 general physics ,0210 nano-technology ,Anisotropy ,Majorana equation ,Phase diagram - Abstract
International audience; We study the formation of Majorana states in quasi-one-dimensional (quasi-1D) and two-dimensional square lattices with open boundary conditions, with general anisotropic Rashba coupling, in the presence of an applied Zeeman field and in the proximity of a superconductor. For systems in which the length of the system is very large (quasi-1D) we calculate analytically the exact topological invariant, and we find a rich corresponding phase diagram which is strongly dependent on the width of the system. We compare our results with previous results based on a few-band approximation. We also investigate numerically open two-dimensional systems of finite length in both directions. We use the recently introduced generalized Majorana polarization, which can locally evaluate the Majorana character of a given state. We find that the formation of Majoranas depends strongly on the geometry of the system: for a very elongated wire the finite-size numerical phase diagram reproduces the analytical phase diagram for infinite systems, while if the length and the width are comparable, no Majorana states can form; however, one can show the formation of “quasi-Majorana” states that have a local Majorana character but no global Majorana symmetry.
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- 2016
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15. P095 Intravenous fosfomycin for treatment of pulmonary exacerbations in adult cystic fibrosis patients with chronic infection by Pseudomonas aeruginosa and other Gram-negative bacteria
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G. Bonizzoni, C. Bena, E. Clivati, F. Traversa, Carlo Albera, M. Bellocchia, S. Demichelis, G.P. Bandelli, B. Messore, and C. Biglia
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Pulmonary and Respiratory Medicine ,Gram-negative bacteria ,biology ,business.industry ,Pseudomonas aeruginosa ,Fosfomycin ,biology.organism_classification ,medicine.disease_cause ,medicine.disease ,Cystic fibrosis ,Microbiology ,Chronic infection ,Pediatrics, Perinatology and Child Health ,Medicine ,business ,medicine.drug - Published
- 2018
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16. P103 Clinical effects of omalizumab in adult cystic fibrosis patients with allergic severe asthma associated with allergic bronchopulmonary aspergillosis
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S. Demichelis, F. Traversa, B. Messore, A. Grande, M. Bellocchia, C. Biglia, Carlo Albera, F.L.M. Ricciardolo, G. Bonizzoni, E. Clivati, and C. Bena
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,business.industry ,Severe asthma ,Pediatrics, Perinatology and Child Health ,Medicine ,Omalizumab ,Allergic bronchopulmonary aspergillosis ,business ,medicine.disease ,Dermatology ,Cystic fibrosis ,medicine.drug - Published
- 2018
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17. Frequency-domain measurement of the spin-imbalance lifetime in superconductors
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Marco Aprili, Denis Chevallier, C. Dutreix, C. H. L. Quay, and C. Bena
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Population ,FOS: Physical sciences ,02 engineering and technology ,Electron ,01 natural sciences ,symbols.namesake ,Pauli exclusion principle ,Condensed Matter::Superconductivity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,010306 general physics ,education ,Spin-½ ,Physics ,Superconductivity ,education.field_of_study ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Order (ring theory) ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Quasiparticle ,symbols ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,Excitation - Abstract
We have measured the lifetime of spin imbalances in the quasiparticle population of a superconductor ($\tau_s$) in the frequency domain. A time-dependent spin imbalance is created by injecting spin-polarised electrons at finite excitation frequencies into a thin-film mesoscopic superconductor (Al) in an in-plane magnetic field (in the Pauli limit). The time-averaged value of the spin imbalance signal as a function of excitation frequency, $f_{RF}$ shows a cut-off at $f_{RF} \approx 1/(2\pi\tau_s)$. The spin imbalance lifetime is relatively constant in the accessible ranges of temperatures, with perhaps a slight increase with increasing magnetic field. Taking into account sample thickness effects, $\tau_s$ is consistent with previous measurements and of the order of the electron-electron scattering time $\tau_{ee}$. Our data are qualitatively well-described by a theoretical model taking into account all quasiparticle tunnelling processes from a normal metal into a superconductor., Comment: Includes Supplementary Information
- Published
- 2016
18. Majoranas with and without a 'character': hybridization, braiding and chiral Majorana number
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P. Simon, Nicholas Sedlmayr, M. Guigou, C. Bena, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), European Project: 256965,NANOGRAPHENE, and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)
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Class (set theory) ,FOS: Physical sciences ,topological superconductor ,02 engineering and technology ,01 natural sciences ,Theoretical physics ,Dimension (vector space) ,0103 physical sciences ,Bound state ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,braiding ,General Materials Science ,Invariant (mathematics) ,010306 general physics ,Physics ,[PHYS]Physics [physics] ,Condensed Matter - Mesoscale and Nanoscale Physics ,Pacs Numbers: 73.20.-r, 73.63.Nm, 74.78.Fk ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,MAJORANA ,Character (mathematics) ,Symmetry (geometry) ,0210 nano-technology ,Mirror symmetry ,Majorana - Abstract
In this paper we demonstrate under what conditions a pseudo-spin degree of freedom or character can be ascribed to the Majorana bound states (MBS) which can be created at the end of one dimensional non-interacting systems, corresponding to D, DIII and BDI in the usual classification scheme. We have found that such a character is directly related to the class of the topological superconductor and its description by a $\mathbb{Z}$, rather than a $\mathbb{Z}_2$, invariant which corresponds to the BDI class. We have also found that the DIII case with mirror symmetry, which supports multiple MBS, is in fact equivalent to the BDI class with an additional time-reversal symmetry. In all cases where a character can be given to the Majorana states we show how to construct the appropriate operator explicitly in various examples. We also examine the consequences of the Majorana character by considering possible hybridization of MBS brought into proximity and find that two MBS with the same character do not hybridize. Finally, we show that having this character or not has no consequence on the braiding properties of MBS., Comment: 10 pages, 1 figure
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- 2015
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19. Flat Majorana bands in two-dimensional lattices with inhomogeneous magnetic fields: Topology and stability
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Nicholas Sedlmayr, J. M. Aguiar-Hualde, C. Bena, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), and European Project: 256965,NANOGRAPHENE
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Physics ,Superconductivity ,[PHYS]Physics [physics] ,Condensed matter physics ,71.70.Ej, 73.20.-r, 73.22.Pr, 74.45.+c ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Topology ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Magnetic field ,MAJORANA ,Coupling (physics) ,Quantum mechanics ,0103 physical sciences ,Bound state ,Weak topology (polar topology) ,PACS number(s): 71.70.Ej, 73.20.−r, 73.22.Pr, 74.45.+c ,010306 general physics ,0210 nano-technology ,Topology (chemistry) ,Phase diagram - Abstract
13 pages, 17 figures; International audience; In this paper we show that for a range of configurations of inhomogeneous magnetic fields it is possible to create flat bands of Majorana states localized on the edges of 2-d lattices. Majorana bound states have been predicted to exist in both one dimensional and two dimensional systems with Rashba spin-orbit coupling, magnetic fields, and placed in proximity to a superconductor. For the proposed systems we present the bulk topological phase diagrams, and we study the conditions for weak topology which predicts the formation of bands of Majorana states. The Majorana bands are demonstrated to be relatively stable with respect to a variety of different perturbations on both square and hexagonal lattices.
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- 2015
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20. Separation of highly fluorescent proteins by SDS-PAGE in Acroporidae corals
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R. van Woesik, Y. Sakihama, C. Bena, Hideo Yamasaki, and M. Papina
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Molecular mass ,Ultraviolet Rays ,Physiology ,ved/biology ,Green Fluorescent Proteins ,ved/biology.organism_classification_rank.species ,Analytical chemistry ,Scleractinia ,Biology ,biology.organism_classification ,Biochemistry ,Fluorescence ,Acroporidae ,Cnidaria ,Luminescent Proteins ,chemistry.chemical_compound ,Spectrometry, Fluorescence ,chemistry ,Animals ,Acropora ,Electrophoresis, Polyacrylamide Gel ,Sodium dodecyl sulfate ,Molecular Biology ,Polyacrylamide gel electrophoresis ,Acropora tenuis - Abstract
This study characterized the spectral properties of Acropora tenuis, A. nasuta, A. secale, and A. aspera, all of which showed strong colorful fluorescence under ultraviolet light-A (black light). The emission maxima of fluorescence from the intact corals were 517, 482, 484, and 514 nm in A. tenuis, A. nasuta, A. secale, and A. aspera, respectively. Using a soluble fraction of cell-free extract of the corals, we applied a method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to separate each fluorescent protein component contained in the corals. Green fluorescent bands were detected in all Acropora examined, although their apparent molecular mass and relative content were different. A. aspera had two orange bands in addition to the green one. The major excitation and emission peaks of the orange fluorescence bands were almost identical (476 and 478 nm), however, they were discernible by their spectral profiles and molecular masses. Some biochemical properties of the highly fluorescent proteins of Acropora are described and implications of the results are discussed.
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- 2002
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21. Two-Propagation-Modes and Dual-Band Antenna for Circular Polarized TX/RX Systems at C-Band
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I. Herrero-Sebastian and C. Benavente-Peces
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siw ,phase-shifter ,dual-band ,circular-polarization ,array ,slot ,c-band ,5g ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This paper presents a novel slotted array for dual-band and circular-polarized applications. Two different propagation modes within a Substrate Integrated Waveguide (SIW), TE10 and TE20, feed at the same time two pairs of slots, aimed at different frequency bands. The pairs are properly placed to be illuminated by an only propagation mode, whereas the magnetic field of the other propagation mode presents a null. Unlike many dual-band slot arrays, this novel antenna holds the same beam tilt for both frequency bands by a new method, which is only feasible through the use of two propagation modes. A dual-mode transition, based on a double microstrip input, allows to excite both propagation modes within the SIW, and it can be fed by a novel single layer dual-band phase shifter with a different shift at each frequency. A square patch is placed over each pair of slots to increase the coupled energy per element, resulting in a low polarization loss and high performance compact antenna at 3.5GHz and 6GHz for dual-band TX/RX systems at C-Band.
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- 2022
22. Glutamatergic dysfunction, neuroplasticity, and redox status in patients with functional movement disorders
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B. Demartini, V. Nisticò, C. Benayoun, A. C. Cigognini, R. Ferrucci, A. Vezzoli, C. Della Noce, O. Gambini, A. Priori, and S. Mrakic-Sposta
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Psychiatry ,RC435-571 - Abstract
Introduction Functional Movement Disorders (FMD) are characterized by the presence of neurological symptoms that cannot be explained by typical neurological diseases or other medical conditions. First evidence showed that, compared to healthy controls (CTR), FMD patients presented increased levels of glutamate+glutamine in the anterior cingulate cortex/medial prefrontal cortex, and decreased levels of glutamate in the cerebrospinal fluid, suggesting that a glutamatergic dysfunction might play a role in FMD pathophysiology. Objectives According to the evidence of these abnormalities in many neuropsychiatric disorders at level of brain network activity, connectivity, and specific anatomic areas of altered metabolic, and given the evidence of a potential role of glutamate and BDNF in the pathophysiology of FND, in this study we aimed to assess circulating levels of glutamate, BDNF, dopamine, oxidative stress biomarkers, creatinine, neopterin and uric acid in patients with FMD and in a control group of healthy subjects. Methods 12 FMD patients (4 males, 8 females) and 20 CTR (4 males, 16 females) were recruited and underwent venous blood sampling and urine collection: levels of glutamate, BDNF, dopamine, oxidative stress, creatine, neopterin, and uric acid were analysed. Participants also underwent a psychometric assessment investigating depression, anxiety, and alexithymia. Results Levels of glutamate, BDNF and dopamine were significantly lower in the blood of FMD patients than CTR. Glutamate and dopamine levels were positively associated with levels of alexithymia. Conclusions Our findings give further evidence that glutamatergic dysfunction might be involved in the pathophysiology of FMD, possibly representing a biomarker of disease; moreover, since glutamatergic and dopaminergic system are closely interconnected, our results might have a relevance in terms of treatment options for FMD patients. Disclosure of Interest None Declared
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- 2023
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23. Life-threatening complications of streptococcal sepsis: a PICU contemporary series
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M. Piastra, V. Ferrari, E. Picconi, T. C. Morena, L. Pezza, G. De Rosa, M. C. Fedele, O. Genovese, R. Onesimo, A. Tempera, P. Valentini, D. Buonsenso, F. Visconti, G. Zito, C. Benassi, and G. Conti
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Streptococcal sepsis complications ,Intensive care ,Mechanical ventilation ,Septic shock ,Tissue tropism phenotypes ,Anesthesiology ,RD78.3-87.3 ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Abstract Background Life-threatening streptococcal sepsis nowadays represents an uncommon event in previously healthy infants and children. Critically ill patients suffering from severe streptococcal sepsis complications may present with pre-antibiotic era clinical pictures and require a timely clinical approach to achieve restitutio ad integrum. Results We report a series of four patient groups affected by an uncommon life-threatening streptococcal sepsis, each of them exhibiting some distinct features. Streptococcus Agalactiae sepsis was associated with cerebral thrombotic/ischaemic lesions, whereas severe cardiogenic shock was prominent in the Streptococcus Viridans group; Streptococcus Faecalis and β-hemolytic group A Streptococcus patients mostly reported lung complications. Conclusions Previous antibiotic treatments should not delay aggressive treatment in the intensive care setting. Early diagnostic suspicion, as well as appropriate and aggressive treatment provided within an intensive care setting are crucial for the clinical outcome.
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- 2021
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24. Density of states of interacting quantum wires with impurities: a Dyson equation approach
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M. Guigou, R. Zamoum, Adeline Crépieux, C. Bena, Centre de Physique Théorique - UMR 7332 (CPT), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), European Project: 256965,NANOGRAPHENE, CPT - E6 Nanophysique, Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)
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Physics ,[PHYS]Physics [physics] ,Local density of states ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Quantum wire ,FOS: Physical sciences ,Condensed Matter Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,010305 fluids & plasmas ,Electronic, Optical and Magnetic Materials ,Momentum ,Impurity ,Luttinger liquid ,Quantum mechanics ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Density of states ,Coulomb ,Condensed Matter::Strongly Correlated Electrons ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,010306 general physics ,Quantum ,[PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall] - Abstract
We calculate the density of states for an interacting quantum wire in the presence two impurities of arbitrary potential strength. To perform this calculation, we describe the Coulomb interactions in the wire within the Tomonaga-Luttinger liquid theory. After establishing and solving the Dyson equation for the fermionic retarded Green's functions, we study how the profile of the local density of states is affected by the interactions in the entire range of impurity potentials. Same as in the non-interacting case, when increasing the impurity strength, the central part of the wire becomes more and more disconnected from the semi-infinite leads, and discrete localized states begin to form; the width of the corresponding peaks in the spectrum depends on the interaction strength. As expected from the Luttinger liquid theory, impurities also induce a reduction of the local density of states at small energies. Two other important aspects are highlighted: the appearance of an extra-modulation in the density of states at non-zero Fermi momentum when interactions are present, and the fact that forward scattering must be taken into account in order to recover the Coulomb blockade regime for strong impurities., Comment: 12 pages, 12 figures
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- 2014
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25. Providing ramps in rearing aviaries affects laying pullet distribution, behavior and bone properties
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A. Stratmann, D. Guggisberg, C. Benavides-Reyes, J. Siegford, and M.J. Toscano
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keel ,transition ,rear ,development ,bone health ,Animal culture ,SF1-1100 ,Food processing and manufacture ,TP368-456 - Abstract
SUMMARY: To ensure that laying hens can make full use of the various resources within an aviary barn and develop optimum bone health while minimizing keel bone fractures, appropriate cognitive and bone development during rearing is critical. Given previous work documenting the benefit of ramps that could be used by hens to transition between tiers and reduced incidence of keel bone fractures, the project examined the provision of ramps during the rearing period, which birds could use voluntarily from 10 d of age. We hypothesized that the provision of ramps would influence how pullets distribute within the aviary and how birds vertically move between the aviary tiers leading to greater bone strength in birds with access to ramps. The study used 2 flocks of laying hen chicks (Lohmann Selected Leghorn; 4,800 chicks/flock) that were reared in one of 2 commercial rearing facilities with each divided into 4 pens (600 chicks/pen) to allow for treatment assignments. In 2 pens of each facility, ramps were installed from each of the 3 tiers providing a walking path that birds could access from 10 d of age. Video recordings were made at 4 times per day at 3, 4, 5, 8, 11, and 14 wk of age to determine the relative distribution of birds and the number of transitions between each tier. At 16 wk of age, 10 birds per pen per flock were killed and the tibia and humerus collected for biomechanical assessment; the keel was also collected for bone mineral density via computed tomography. Chicks/pullets within pens provided ramps demonstrated a rapid use of the upper tiers of the aviary paralleling greater usage of ramps between all aviary levels. Despite the ramp and tier usage following the predicted pattern, differences in bone strength were opposite than expected for tibiae and may reflect the different behaviors pens with ramps and without ramps would allow. Results support the position that provision of ramps within a commercial system will lead to voluntary usage of the ramps with long term effects on the distribution of birds in the system throughout the rearing period.
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- 2022
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26. Majorana Fermions in Graphene and Graphene-Like Materials
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C. Dutreix, M. Guigou, D. Chevallier, and C. Bena
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- 2013
27. From Andreev bound states to Majorana fermions in topological wires on superconducting substrates : a story of mutation
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Pascal Simon, C. Bena, and Denis Chevallier
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Nanowire ,FOS: Physical sciences ,02 engineering and technology ,Topology ,01 natural sciences ,Superconductivity (cond-mat.supr-con) ,Quantum mechanics ,Condensed Matter::Superconductivity ,0103 physical sciences ,Bound state ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Proximity effect (superconductivity) ,010306 general physics ,Superconductivity ,Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed matter physics ,Condensed Matter - Superconductivity ,Fermion ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Electronic, Optical and Magnetic Materials ,MAJORANA ,Coupling (physics) ,Quasiparticle ,0210 nano-technology - Abstract
We study the proximity effect in a topological nanowire tunnel coupled to an s-wave superconducting substrate. We use a general Green's function approach that allows us to study the evolution of the Andreev bound states in the wire into Majorana fermions. We show that the strength of the tunnel coupling induces a topological transition in which the Majorana fermionic states can be destroyed when the coupling is very strong. Moreover, we provide a phenomenologial study of the effects of disorder in the superconductor on the formation of Majorana fermions. We note a non-trivial effect of a quasiparticle broadening term which can take the wire from a topological into a non-topological phase in certain ranges of parameters. Our results have also direct consequences for a nanowire coupled to an inhomogenous superconductor.
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- 2013
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28. Spin and Majorana Polarization in Topological Superconducting Wires
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Doru Sticlet, Pascal Simon, and C. Bena
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FOS: Physical sciences ,General Physics and Astronomy ,02 engineering and technology ,Topology ,01 natural sciences ,Superconductivity (cond-mat.supr-con) ,Physics::Popular Physics ,symbols.namesake ,Quantum mechanics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,010306 general physics ,Condensed Matter::Quantum Gases ,Superconductivity ,Physics ,Zeeman effect ,Condensed Matter - Mesoscale and Nanoscale Physics ,Spin polarization ,Condensed matter physics ,Condensed Matter - Superconductivity ,High Energy Physics::Phenomenology ,Fermion ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Polarization (waves) ,Physics::History of Physics ,Magnetic field ,MAJORANA ,Density of states ,symbols ,0210 nano-technology - Abstract
We study a one-dimensional wire with strong Rashba and Dresselhaus spin-orbit coupling (SOC), which supports Majorana fermions when subject to a Zeeman magnetic field and in proximity of a superconductor. Using both analytical and numerical techniques we calculate the electronic spin texture of the Majorana end states. We find that the spin polarization of these states depends on the relative magnitude of the Rashba and Dresselhaus SOC components. Moreover, we define and calculate a local "Majorana polarization" and "Majorana density" and argue that they can be used as order parameters to characterize the topological transition between the trivial system and the system exhibiting Majorana bound modes. We find that the local "Majorana polarization" is correlated to the transverse spin polarization, and we propose to test the presence of Majorana fermions in a 1D system by a spin-polarized density of states measurement., Comment: 6 pages, 5 figures, RevTeX4; added analytical results section and supplementary material; new references added
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- 2012
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29. Theoretical analysis of the density of states of graphene at high magnetic field using Haldane pseudopotentials
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Lih-King Lim, Mark Oliver Goerbig, and C. Bena
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FOS: Physical sciences ,02 engineering and technology ,Electron ,7. Clean energy ,01 natural sciences ,Measure (mathematics) ,law.invention ,Pseudopotential ,Condensed Matter - Strongly Correlated Electrons ,law ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,010306 general physics ,Physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Graphene ,Landau quantization ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,3. Good health ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Density of states ,Scanning tunneling microscope ,0210 nano-technology - Abstract
We study the density of states in graphene at high magnetic field, when the physics is dominated by strong correlations between electrons. In particular we use the method of Haldane pseudopotentials to focus on almost empty or almost filled Landau levels. We find that, besides the usual Landau level peaks, additional peaks ("sashes") appear in the spectrum. The energies of these peaks are determined by the strength of Haldane's pseudopotentials, but as opposed to the usual two-dimensional gas, when there is a one-to-one correspondence between a Haldane pseudopotential and a peak in the spectrum, the energy of each peak is determined in general by a combination of more than one pseudopotential values. An eventual measure of these peak in the density of states spectrum of graphene would allow one to determine the value of the pseudopotentials in graphene, and thus test the strength of the interactions in this system., 9 pages, 1 table
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- 2011
30. Superlattice of resonators on monolayer graphene created by intercalated gold nanoclusters
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M. Cranney, P. B. Pillai, François Vonau, C. Bena, Dominique Aubel, M.M. De Souza, L. Simon, and Emmanuel Denys
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Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed matter physics ,Graphene ,Superlattice ,Scanning tunneling spectroscopy ,General Physics and Astronomy ,Physics::Optics ,FOS: Physical sciences ,Electronic structure ,law.invention ,Nanoclusters ,Quantum dot ,law ,Condensed Matter::Superconductivity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Quasiparticle ,Physics::Atomic and Molecular Clusters ,Physics::Chemical Physics ,Electronic band structure - Abstract
Here we report on a "new" type of ordering which allows to modify the electronic structure of a graphene monolayer (ML). We have intercalated small gold clusters between the top monolayer graphene and the buffer layer of epitaxial graphene. We show that these clusters perturb the quasiparticles on the ML graphene, and act as quantum dots creating a superlattice of resonators on the graphene ML, as revealed by a strong pattern of standing waves. A detailed analysis of the standing wave patterns using Fourier Transform Scanning Tunneling Spectroscopy strongly indicates that this phenomenon can arise from a strong modification of the band structure of graphene and (or) from Charge Density Waves (CDW)where a large extension of Van Hove singularities are involved., Comment: 12 pages, 5 figures
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- 2010
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31. AC conductance and non-symmetrized noise at finite frequency in quantum wires and carbon nanotubes
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Adeline Crépieux, Inès Safi, C. Bena, Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre de Physique Théorique - UMR 6207 (CPT), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Université de Provence - Aix-Marseille 1-Université de la Méditerranée - Aix-Marseille 2, Centre de Physique Théorique - UMR 7332 (CPT), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), and Université de la Méditerranée - Aix-Marseille 2-Université de Provence - Aix-Marseille 1-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)
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noise ,media_common.quotation_subject ,FOS: Physical sciences ,02 engineering and technology ,Carbon nanotube ,01 natural sciences ,Asymmetry ,law.invention ,Condensed Matter - Strongly Correlated Electrons ,Luttinger liquid ,law ,Impurity ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,010306 general physics ,Quantum ,[PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall] ,media_common ,AC conductance ,Physics ,Condensed matter physics ,Strongly Correlated Electrons (cond-mat.str-el) ,carbon nanotubes ,Condensed Matter - Mesoscale and Nanoscale Physics ,Linear system ,quantum wires ,Conductance ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Electronic, Optical and Magnetic Materials ,Conductance quantum ,[PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el] ,0210 nano-technology - Abstract
International audience; We calculate the AC conductance and the finite-frequency non-symmetrized noise in interacting quantum wires and single-wall carbon nanotubes in the presence of an impurity. We observe a strong asymmetry in the frequency spectrum of the non-symmetrized excess noise, even in the presence of the metallic leads. We find that this asymmetry is proportional to the differential excess AC conductance of the system, defined as the difference between the AC differential conductances at finite and zero voltage, and thus disappears for a linear system. In the quantum regime, for temperatures much smaller than the frequency and the applied voltage, we find that the emission noise is exactly equal to the impurity partition noise. For the case of a weak impurity we expand our results for the AC conductance and the noise perturbatively. In particular, if the impurity is located in the middle of the wire or at one of the contacts, our calculations show that the noise exhibits oscillations with respect to frequency, whose period is directly related to the value of the interaction parameter $g$.
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- 2008
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32. Symmetry of standing waves generated by a point defect in epitaxial graphene
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C. Bena, L. Simon, Dominique Aubel, J. C. Perruchetti, Hussein Nasrallah, François Vonau, and M. Habar
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Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed matter physics ,Graphene ,media_common.quotation_subject ,FOS: Physical sciences ,Electron ,Condensed Matter Physics ,Asymmetry ,Electronic, Optical and Magnetic Materials ,law.invention ,Standing wave ,Condensed Matter::Materials Science ,law ,Condensed Matter::Superconductivity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Quasiparticle ,Fermi liquid theory ,Scanning tunneling microscope ,Anisotropy ,media_common - Abstract
Using scanning tunneling microscopy (STM) and Fourier Transform STM (FT-STM), we have studied a point defect in an epitaxial graphene sample grown on silicon carbide substrate. This analysis allows us to extract the quasiparticle energy dispersion, and to give a first experimental proof of the validity of Fermi liquid theory in graphene for a wide range of energies from -800 meV to +800 meV. We also find evidence of a strong threefold anisotropy in the standing waves generated by the defect. We discuss possible relations between this anisotropy, the chirality of the electrons, and the asymmetry between graphene's two sublattices. All experimental measurements are compared and related to theoretical T-matrix calculations., Comment: 4 pages, 4 figures
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- 2008
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33. P508: REAL LIFE EXPERIENCE USING FRONT-LINE CPX-351 FOR THERAPY-RELATED AND AML-MRC: RESULTS FROM THE SPANISH PETHEMA REGISTRY.
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T. Bernal, G. Rad, A. de Laiglesia, C. Benavente, A. Garcia Noblejas, D. Garcia Belmonte, R. Riaza, O. Salamero, A. Foncillas, A. Roldán, V. Noriega Concepcion, J. Perez de Oteyza, J. M. Bergua Burgues, S. Lorente de Uña, A. de la Fuente Burguera, M. J. Garcia Perez, J. L. Lopez Lorenzo, P. Martinez, C. Alaez, M. Callejas, C. Martinez Chamorro, J. Rifon Roca, L. Amador Barciela, M. Lopez, K. Gomez Correcha, E. Lavilla Rubiera, M. L. Amigo, F. Vall-Llovera, A. Garrido, M. Garcia Fortes, D. de Miguel Llorente, A. Aules Leonardo, C. Cervero, R. Coll Jorda, M. Perez Encinas, M. Polo Zarzuela, D. Martinez Cuadron, and P. Montesinos
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Diseases of the blood and blood-forming organs ,RC633-647.5 - Published
- 2022
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34. PB2239: DOES SIZE MATTER? THREE NEW DELETIONS IN THE HBB GENE CAUSE Β0-THALASSEMIA
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P. Ropero, F. A. González, J. M. Nieto, V. Recasens, Á. Montañés, M. J. Murúzabal, M. Sarasa, C. Fernández, A. Calo, M. Gómez, S. Escribano, H. Martín, S. Rochas, A. Villegas, C. Benavente, and G. E. de Eritropatología
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Diseases of the blood and blood-forming organs ,RC633-647.5 - Published
- 2022
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35. PB2238: ΒETA-THALASSEMIA INTERMEDIA: INTERACTION OF ΑLPHA-GLOBIN GENE TRIPLICATION WITH ΒETA-THALASSEMIA HETEROZYGOUS IN SPAIN
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P. Ropero, F. A. González, J. M. Nieto, W. M. Torres-Jiménez, B. Colas, P. Estival, A. Calo, S. Escribano, S. Rochas, A. Villegas, C. Benavente, and G. E. de Eritropatología
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Diseases of the blood and blood-forming organs ,RC633-647.5 - Published
- 2022
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36. PB2237: HEMATIMETRIC DETECTION OF THE TRIPLICATION OF ALPHA-GLOBIN GENES. THE IMPORTANCE OF YOUR DIAGNOSIS
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P. Ropero, F. A. González, J. M. Nieto, S. Rochas, M. Gómez, B. Colás, H. Martín, P. Estival, A. Villegas, C. Benavente, and G. E. de Eritropatología
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Diseases of the blood and blood-forming organs ,RC633-647.5 - Published
- 2022
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37. 202 Pulmonary tomosynthesis in adults with cystic fibrosis: Our preliminary experience
- Author
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A. Veltri, C. Bena, P. Nespoli, Giancarlo Cortese, D. Parlatano, B. Messore, and M. Chiesa
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,business.industry ,Pediatrics, Perinatology and Child Health ,Medicine ,Pediatrics, Perinatology, and Child Health ,Radiology ,business ,medicine.disease ,Cystic fibrosis ,Tomosynthesis - Published
- 2013
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38. 201 CT findings in cystic fibrosis diagnosed in adulthood
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B. Messore, M. Chiesa, P. Nespoli, C. Bena, A. Veltri, Giancarlo Cortese, and D. Parlatano
- Subjects
Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,business.industry ,Pediatrics, Perinatology and Child Health ,Medicine ,Pediatrics, Perinatology, and Child Health ,Ct findings ,Radiology ,urologic and male genital diseases ,business ,medicine.disease ,Cystic fibrosis - Published
- 2013
- Full Text
- View/download PDF
39. Vortioxetine Prevents Lipopolysaccharide-Induced Memory Impairment Without Inhibiting the Initial Inflammatory Cascade
- Author
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S. Alboni, C. Benatti, C. Colliva, G. Radighieri, J. M. C. Blom, N. Brunello, and F. Tascedda
- Subjects
microglia ,sickness behavior ,lipopolysaccharide (LPS) ,vortioxetine ,hippocampus ,neuroinflammation ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Vortioxetine is a novel multimodal antidepressant that modulates a wide range of neurotransmitters throughout the brain. Preclinical and clinical studies have shown that vortioxetine exerts positive effects on different cognitive domains and neuroprotective effects. Considering the key role of microglial cells in brain plasticity and cognition, we aimed at investigating the effects of pretreatment with vortioxetine in modulating behavioral and molecular effects induced by an immune challenge: peripheral injection of lipopolysaccharide (LPS). To this purpose, C57BL/6J male mice were first exposed to a 28-day standard diet or vortioxetine-enriched diet, which was followed by an acute immune challenge with LPS. Sickness symptoms and depressive-like behaviors (anhedonia and memory impairment) were tested 6 and 24 h after exposure to LPS, respectively. Moreover, the expressions of markers of immune activation and M1/M2 markers of microglia polarization were measured in the dorsal and ventral parts of the hippocampus. The pretreatment with vortioxetine did not affect both LPS-induced sickness behavior and anhedonia but prevented the deficit in the recognition memory induced by the immune challenge. At the transcriptional level, chronic exposure to vortioxetine did not prevent LPS-induced upregulation of proinflammatory cytokines 6 h after the immune challenge but rather seemed to potentiate the immune response to the challenge also by affecting the levels of expression of markers of microglia M1 phenotype, like cluster of differentiation (CD)14 and CD86, in an area-dependent manner. However, at the same time point, LPS injection significantly increased the expression of the M2 polarization inducer, interleukin 4, only in the hippocampus of animals chronically exposed to vortioxetine. These results demonstrate that a chronic administration of vortioxetine specifically prevents LPS-induced memory impairment, without affecting acute sickness behavior and anhedonia, and suggest that hippocampal microglia may represent a cellular target of this novel antidepressant medication. Moreover, we provide a useful model to further explore the molecular mechanisms specifically underlying cognitive impairments following an immune challenge.
- Published
- 2021
- Full Text
- View/download PDF
40. Generation of Mycoplasma hominis gene-targeted mutants by targeting-induced local lesions in genomes (TILLING)
- Author
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S. Pereyre, C. Bénard, C. Brès, C. Le Roy, J. P. Mauxion, F. Rideau, P. Sirand-Pugnet, B. Henrich, and C. Bébéar
- Subjects
Mycoplasma hominis ,Chemical mutagenesis ,Ethyl methanesulfonate ,TILLING ,Biotechnology ,TP248.13-248.65 ,Genetics ,QH426-470 - Abstract
Abstract Background Mycoplasma hominis is a human urogenital pathogen involved in gynaecological, neonatal and extra-genital infections. However, no versatile genetic tools are currently available to study the pathogenicity of this bacterium. Targeting-Induced Local Lesions IN Genomes (TILLING) is a reverse-genetic method that combines point mutations induced by chemical mutagenesis with a DNA screening technique. We used ethyl methanesulfonate (EMS) that introduces C-G to T-A transition mutations to generate a library of M. hominis mutants. As a proof of concept, mutagenized organisms were screened for mutations in two target genes previously associated with the mycoplasma pathogenicity, the vaa gene encoding an adhesin lipoprotein and the oppA gene encoding the main ectoATPase of the bacterium. The resulting mutants were evaluated using functional assays, an adhesion to HeLa cell assay for vaa-mutants and an ATPase activity test for oppA-mutants. Results A 1200-clone library was generated by exposing M. hominis PG21 to 9 mg/mL EMS for 3 h. To identify mutants of interest, targeted gene fragments were amplified, heat-denatured, slowly reannealed and digested with the mismatch-specific endonuclease ENDO1. If multiple alleles were present in the PCR amplicons, these alleles formed heteroduplexes during reannealing that were specifically cleaved by ENDO1 at mismatching positions. A total of four vaa-mutants and two oppA-mutants harbouring missense mutations were obtained and fully sequenced. Zero to eight additional mutations were identified in the genomes of each mutant. The vaa-mutants were tested for adhesion to immobilized HeLa cells but their adhesion was not significantly different from the adhesion of M. hominis PG21. One of the two oppA-mutants that were tested for ATPase activity presented a higher affinity for its ATP substrate than the parental strain. Conclusion For the first time, we demonstrated that M. hominis gene-targeted mutants could be successfully obtained using this TILLING strategy. In the absence of robust genetic tools for studying M. hominis, the TILLING strategy that can target any gene of the genome could help to elucidate gene functions and to better understand the pathogenesis of this human pathogenic species.
- Published
- 2018
- Full Text
- View/download PDF
41. Control of laser plasma accelerated electrons for light sources
- Author
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T. André, I. A. Andriyash, A. Loulergue, M. Labat, E. Roussel, A. Ghaith, M. Khojoyan, C. Thaury, M. Valléau, F. Briquez, F. Marteau, K. Tavakoli, P. N’Gotta, Y. Dietrich, G. Lambert, V. Malka, C. Benabderrahmane, J. Vétéran, L. Chapuis, T. El Ajjouri, M. Sebdaoui, N. Hubert, O. Marcouillé, P. Berteaud, N. Leclercq, M. El Ajjouri, P. Rommeluère, F. Bouvet, J. -P. Duval, C. Kitegi, F. Blache, B. Mahieu, S. Corde, J. Gautier, K. Ta Phuoc, J. P. Goddet, A. Lestrade, C. Herbeaux, C. Évain, C. Szwaj, S. Bielawski, A. Tafzi, P. Rousseau, S. Smartsev, F. Polack, D. Dennetière, C. Bourassin-Bouchet, C. De Oliveira, and M.-E. Couprie
- Subjects
Science - Abstract
Electron beam quality in accelerators is crucial for light source application. Here the authors demonstrate beam conditioning of laser plasma electrons thanks to a specific transport line enabling the control of divergence, energy, steering and dispersion and the application to observe undulator radiation.
- Published
- 2018
- Full Text
- View/download PDF
42. Tectonic and climatic controls on the Chuquibamba landslide (western Andes, southern Peru)
- Author
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A. Margirier, L. Audin, J. Carcaillet, S. Schwartz, and C. Benavente
- Subjects
Dynamic and structural geology ,QE500-639.5 - Abstract
The contribution of landslides to the Quaternary evolution of relief is poorly documented in arid contexts. In southern Peru and northern Chile, several massive landslides disrupt the arid western Andean front. The Chuquibamba landslide, located in southern Peru, belongs to this set of large landslides. In this area, the Incapuquio fault system captures the intermittent drainage network and localizes rotational landslides. Seismic activity is significant in this region with recurrent Mw 9 subduction earthquakes; however, none of the latest seismic events have triggered a major landslide. New terrestrial cosmogenic dating of the Chuquibamba landslide provides evidence that the last major gravitational mobilization of these rotational landslide deposits occurred at ~ 102 ka, during the Ouki wet climatic event identified on the Altiplano between 120 and 98 ka. Our results suggest that wet events in the arid and fractured context of the Andean forearc induced these giant debris flows. Finally, our study highlights the role of tectonics and climate on (i) the localization of large Andean landslides in the Western Cordillera and on (ii) the long-term mass transfer to the trench along the arid Andean front.
- Published
- 2015
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- View/download PDF
43. Friedel oscillations: Decoding the hidden physics
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C. Bena
- Subjects
Superconductivity ,Physics ,Friedel oscillations ,Oscillations de Friedel ,Local density of states ,Condensed matter physics ,Graphene ,General Engineering ,Energy Engineering and Power Technology ,Physics and Astronomy(all) ,01 natural sciences ,Impurity scattering ,Desordre ,010305 fluids & plasmas ,law.invention ,Dirac electron ,law ,Quantum mechanics ,0103 physical sciences ,Scanning tunneling microscope ,010306 general physics ,Decoding methods ,Electronic properties - Abstract
We show that the impurity-induced Friedel oscillations allow one to probe in an unexpected and quite remarkable manner the electronic properties of two-dimensional systems such as graphene or high-temperature superconductors. In particular, we show that by studying these oscillations, one can get access not only to the constant-energy maps, but also to more hidden information such as the chiral properties of Dirac electrons in graphene, which cannot be observed directly by other methods. For graphene, this hidden information is revealed by comparing the theoretical predictions with scanning tunneling microscopy experimental measurements of the local density of states.
- Full Text
- View/download PDF
44. Integration of stationary wavelet transform on a dynamic partial reconfiguration for recognition of pre-ictal gamma oscillations
- Author
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N. Jmail, M. Zaghdoud, A. Hadriche, T. Frikha, C. Ben Amar, and C. Bénar
- Subjects
Biomedical engineering ,Neurology ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
To define the neural networks responsible of an epileptic seizure, it is useful to perform advanced signal processing techniques. In this context, electrophysiological signals present three types of waves: oscillations, spikes, and a mixture of both. Recent studies show that spikes and oscillations should be separated properly in order to define the accurate neural connectivity during the pre-ictal, seizure and inter-ictal states. Retrieving oscillatory activity is a sensitive task due to the frequency overlap between oscillations and transient activities. Advanced filtering techniques have been proposed to ensure a good separation between oscillations and spikes. It would be interesting to apply them in real time for instantaneous monitoring, seizure warning or neurofeedback systems. This requires improving execution time. This constraint can be overcome using embedded systems that combine hardware and software in an optimized architecture. We propose here to implement a stationary wavelet transform (SWT) as an adaptive filtering technique retaining only pre-ictal gamma oscillations, as validated in previous work, on a partial dynamic configuration. Then, the same architecture is used with further modifications to integrate spatio temporal mapping for an early recognition of seizure build-up. Data that contains transient, pre-ictal gamma oscillations and a seizure was simulated. the method on real intracerebral signals was also tested. The SWT was integrated on an embedded architecture. This architecture permits a spatio temporal mapping to detect the accurate time and localization of seizure build-up, while reducing computation time by a factor of around 40. Embedded systems are a promising venue for real-time applications in clinical systems for epilepsy.
- Published
- 2018
- Full Text
- View/download PDF
45. Robustness of a plasma acceleration based free electron laser
- Author
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M. Labat, A. Loulergue, T. Andre, I. A. Andriyash, A. Ghaith, M. Khojoyan, F. Marteau, M. Valléau, F. Briquez, C. Benabderrahmane, O. Marcouillé, C. Evain, and M. E. Couprie
- Subjects
Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 - Abstract
Laser plasma accelerators (LPA) can sustain GeV/m accelerating fields offering outstanding new possibilities for compact applications. The LPA beam brightness can now be comparable to radio-frequency accelerators’ (RFA), thanks essentially to the beams short duration (
- Published
- 2018
- Full Text
- View/download PDF
46. Publisher Correction: Control of laser plasma accelerated electrons for light sources
- Author
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T. André, I. A. Andriyash, A. Loulergue, M. Labat, E. Roussel, A. Ghaith, M. Khojoyan, C. Thaury, M. Valléau, F. Briquez, F. Marteau, K. Tavakoli, P. N’Gotta, Y. Dietrich, G. Lambert, V. Malka, C. Benabderrahmane, J. Vétéran, L. Chapuis, T. El Ajjouri, M. Sebdaoui, N. Hubert, O. Marcouillé, P. Berteaud, N. Leclercq, M. El Ajjouri, P. Rommeluère, F. Bouvet, J. -P. Duval, C. Kitegi, F. Blache, B. Mahieu, S. Corde, J. Gautier, K. Ta Phuoc, J. P. Goddet, A. Lestrade, C. Herbeaux, C. Évain, C. Szwaj, S. Bielawski, A. Tafzi, P. Rousseau, S. Smartsev, F. Polack, D. Dennetière, C. Bourassin-Bouchet, C. De Oliveira, and M. -E. Couprie
- Subjects
Science - Abstract
The original version of this Article contained an error in the last sentence of the first paragraph of the Introduction and incorrectly read ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime in equation 11, nx(n-β) x β: n the two times and beta the two times should be bold since they are vectorsin Eq. 12, β should be bold as well.’ The correct version is ‘A proper electron beam control is one of the main challenges towards the Graal of developing a compact alternative of X-ray free-electron lasers by coupling LWFA gigaelectron-volts per centimetre acceleration gradient with undulators in the amplification regime.’This has been corrected in both the PDF and HTML versions of the Article.
- Published
- 2018
- Full Text
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47. Role of T-Cell Polarization and Inflammation and Their Modulation by n-3 Fatty Acids in Gestational Diabetes and Macrosomia
- Author
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A. Hichami, O. Grissa, I. Mrizak, C. Benammar, and N. A. Khan
- Subjects
Nutritional diseases. Deficiency diseases ,RC620-627 - Abstract
Th (T helper) cells are differentiated into either Th1 or Th2 phenotype. It is generally considered that Th1 phenotype is proinflammatory, whereas Th2 phenotype exerts anti-inflammatory or protective effects. Gestational diabetes mellitus (GDM) has been associated with a decreased Th1 phenotype, whereas macrosomia is marked with high expression of Th1 cytokines. Besides, these two pathological situations are marked with high concentrations of inflammatory mediators like tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), known to play a pivotal role in insulin resistance. Dietary n-3 polyunsaturated fatty acids (n-3 PUFAs) may exert a beneficial effect by shifting Th1/Th2 balance to a Th2 phenotype and increasing insulin sensitivity. In this paper, we shed light on the role of T-cell malfunction that leads to an inflammatory and pathophysiological state, related to insulin resistance in GDM and macrosomia. We will also discuss the nutritional management of these pathologies by dietary n-3 polyunsaturated fatty acids (PUFAs).
- Published
- 2016
- Full Text
- View/download PDF
48. Development and operation of a Pr_{2}Fe_{14}B based cryogenic permanent magnet undulator for a high spatial resolution x-ray beam line
- Author
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C. Benabderrahmane, M. Valléau, A. Ghaith, P. Berteaud, L. Chapuis, F. Marteau, F. Briquez, O. Marcouillé, J.-L. Marlats, K. Tavakoli, A. Mary, D. Zerbib, A. Lestrade, M. Louvet, P. Brunelle, K. Medjoubi, C. Herbeaux, N. Béchu, P. Rommeluere, A. Somogyi, O. Chubar, C. Kitegi, and M.-E. Couprie
- Subjects
Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 - Abstract
Short period, high field undulators are used to produce hard x-rays on synchrotron radiation based storage ring facilities of intermediate energy and enable short wavelength free electron laser. Cryogenic permanent magnet undulators take benefit from improved magnetic properties of RE_{2}Fe_{14}B (Rare Earth based magnets) at low temperatures for achieving short period, high magnetic field and high coercivity. Using Pr_{2}Fe_{14}B instead of Nd_{2}Fe_{14}B, which is generally employed for undulators, avoids the limitation caused by the spin reorientation transition phenomenon, and simplifies the cooling system by allowing the working temperature of the undulator to be directly at the liquid nitrogen one (77 K). We describe here the development of a full scale (2 m), 18 mm period Pr_{2}Fe_{14}B cryogenic permanent magnet undulator (U18). The design, construction and optimization, as well as magnetic measurements and shimming at low temperature are presented. The commissioning and operation of the undulator with the electron beam and spectrum measurement using the Nanoscopmium beamline at SOLEIL are also reported.
- Published
- 2017
- Full Text
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49. Angiogenesis in Spontaneous Tumors and Implications for Comparative Tumor Biology
- Author
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C. Benazzi, A. Al-Dissi, C. H. Chau, W. D. Figg, G. Sarli, J. T. de Oliveira, and F. Gärtner
- Subjects
Technology ,Medicine ,Science - Abstract
Blood supply is essential for development and growth of tumors and angiogenesis is the fundamental process of new blood vessel formation from preexisting ones. Angiogenesis is a prognostic indicator for a variety of tumors, and it coincides with increased shedding of neoplastic cells into the circulation and metastasis. Several molecules such as cell surface receptors, growth factors, and enzymes are involved in this process. While antiangiogenic therapy for cancer has been proposed over 20 years ago, it has garnered much controversy in recent years within the scientific community. The complex relationships between the angiogenic signaling cascade and antiangiogenic substances have indicated the angiogenic pathway as a valid target for anticancer drug development and VEGF has become the primary antiangiogenic drug target. This review discusses the basic and clinical perspectives of angiogenesis highlighting the importance of comparative biology in understanding tumor angiogenesis and the integration of these model systems for future drug development.
- Published
- 2014
- Full Text
- View/download PDF
50. High gradient quadrupoles for low emittance storage rings
- Author
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G. Le Bec, J. Chavanne, C. Benabderrahmane, L. Farvacque, L. Goirand, S. Liuzzo, P. Raimondi, and F. Villar
- Subjects
Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 - Abstract
High gradient quadrupoles are key components for the coming generation of storage ring based light sources. The typical specifications of these magnets are: almost 100 T/m gradient, half a meter long, and a vertical aperture for the extraction of the x-ray beam. This paper presents the preparation work done at the European Synchrotron Radiation Facility, from the design to the manufacture and measurements of a prototype. It demonstrates the feasibility of such magnets. Different aspects of magnet engineering are discussed, including the study of the main scale factors and the preliminary design, the pole shaping, the impact of mechanical errors, and the magnetic measurements of a prototype with a stretched-wire system.
- Published
- 2016
- Full Text
- View/download PDF
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