492 results on '"Piot, P"'
Search Results
2. Distinct ontogenetic lineages dictate cDC2 heterogeneity
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Minutti, Carlos M., Piot, Cécile, Pereira da Costa, Mariana, Chakravarty, Probir, Rogers, Neil, Huerga Encabo, Hector, Cardoso, Ana, Loong, Jane, Bessou, Gilles, Mionnet, Cyrille, Langhorne, Jean, Bonnet, Dominique, Dalod, Marc, Tomasello, Elena, and Reis e Sousa, Caetano
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Conventional dendritic cells (cDCs) include functionally and phenotypically diverse populations, such as cDC1s and cDC2s. The latter population has been variously subdivided into Notch-dependent cDC2s, KLF4-dependent cDC2s, T-bet+cDC2As and T-bet−cDC2Bs, but it is unclear how all these subtypes are interrelated and to what degree they represent cell states or cell subsets. All cDCs are derived from bone marrow progenitors called pre-cDCs, which circulate through the blood to colonize peripheral tissues. Here, we identified distinct mouse pre-cDC2 subsets biased to give rise to cDC2As or cDC2Bs. We showed that a Siglec-H+pre-cDC2A population in the bone marrow preferentially gave rise to Siglec-H−CD8α+pre-cDC2As in tissues, which differentiated into T-bet+cDC2As. In contrast, a Siglec-H−fraction of pre-cDCs in the bone marrow and periphery mostly generated T-bet−cDC2Bs, a lineage marked by the expression of LysM. Our results showed that cDC2A versus cDC2B fate specification starts in the bone marrow and suggest that cDC2 subsets are ontogenetically determined lineages, rather than cell states imposed by the peripheral tissue environment.
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- 2024
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3. On the Application of some Plasticity Laws
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Hennocque, Louis, Favre, Julien, Meyer, Nicolas, Sourisseau, Thomas, Maurice, Claire, Piot, David, Latu-Romain, Laurence, and Kermouche, Guillaume
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Three main rheological laws are found in the literature to describe the strain hardening of materials at high temperatures. The choice of the most suited law to describe a flow stress curve is often discussed as a function of the nature of the material; but it still remains difficult to choose the most appropriate one. These semi-empirical laws systematically comprise two main terms linked either to the dislocations generation or their annihilation.The objective of this paper is to determine by an inverse method which law appears to be the most suited. It is finally demonstrated that the application of one law is mostly equivalent to another. The various laws are overall equivalent and do not help to describe some peculiar physical mechanism of plasticity.
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- 2023
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4. Why Do Grains Remain Roughly Equiaxed during Steady State Discontinuous Dynamic Recrystallization?
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Montheillet, Frank and Piot, David
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The combination of advection and migration of grain boundaries is analyzed on the basis of a simple mesoscale model, where parallelepipedic grains are considered under uniaxial compression straining. Strain hardening and dynamic recovery are described by the classical Yoshie-Laasraoui-Jonas equation. Grain-boundary migration is driven by the difference in dislocation densities between one representative grain and the average over the material. Finally, nucleation is assumed to occur at grain boundaries. Special attention is paid to the aspect ratio, which starts from unity (infinitely small cubic nucleus) and tends to zero when the grain disappears. In spite of the role of migration, the average shape of the grains is determined as a first approximation by their lifetimes.
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- 2023
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5. Magneto-Optical Sensing of the Pressure Driven Magnetic Ground States in Bulk CrSBr
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Pawbake, Amit, Pelini, Thomas, Mohelsky, Ivan, Jana, Dipankar, Breslavetz, Ivan, Cho, Chang-Woo, Orlita, Milan, Potemski, Marek, Measson, Marie-Aude, Wilson, Nathan P., Mosina, Kseniia, Soll, Aljoscha, Sofer, Zdenek, Piot, Benjamin A., Zhitomirsky, Mike E., and Faugeras, Clement
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Competition between exchange interactions and magnetocrystalline anisotropy may bring new magnetic states that are of great current interest. An applied hydrostatic pressure can further be used to tune their balance. In this work, we investigate the magnetization process of a biaxial antiferromagnet in an external magnetic field applied along the easy axis. We find that the single metamagnetic transition of the Ising type observed in this material under ambient pressure transforms under hydrostatic pressure into two transitions, a first-order spin-flop transition followed by a second-order transition toward a polarized ferromagnetic state near saturation. This reversible tuning into a new magnetic phase is obtained in layered bulk CrSBr at low temperature by varying the interlayer distance using high hydrostatic pressure, which efficiently acts on the interlayer magnetic exchange and is probed by magneto-optical spectroscopy.
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- 2023
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6. Coping with Administrative Workload: a Pilot Study in the Usefulness of a Workshop for Psychiatric Trainees
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Deschamps, Peter, Seker, Asilay, van der Schaaf, Marieke, and Piot, Marie-Aude
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Objective: Administrative workload may have detrimental effects on medical postgraduate trainee satisfaction, capacity, and quality of care. Best-practice guidelines to help trainees cope have yet to be developed. This study explores perceptions of factors that influence the experience or amount of administrative workload at the personal and workplace level and evaluates the usefulness of a workshop on coping with this workload. Methods: A workshop was developed based on the Job Demands-Resources model, including a survey on perceptions of administrative workload; presentation on coping at personal (e.g., time management) and workplace (e.g., dealing with institutional rules) levels; personal plan of change during a group discussion; and reflective questionnaire after the session and again after 2 months. Perceptions of psychiatry trainee participants (N= 48) were collected. Results: Trainees estimated they spent half their time on administration (average 50%, SD= 15%). They wanted to spend less time (average 23%, SD= 11%) on most administrative duties, except for health record keeping. Personal factors that trainees experienced as helpful to cope included time management and analytical skills. Perfectionism was perceived as impeding. Supportive job factors included helpful supervisors, competent administrative staff, trust in a team, allocated timeslots, and information technology support. High workload and cumbersome procedures were mentioned as impeding. On average, trainees rated the workshop quality and the likelihood of bringing change to their practice with a 7 out of 10. Conclusion: Psychiatry trainees’ participation in a workshop on coping with administrative load during their training may be a worthwhile investment in the long term.
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- 2023
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7. Mixing of moiré-surface and bulk states in graphite
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Mullan, Ciaran, Slizovskiy, Sergey, Yin, Jun, Wang, Ziwei, Yang, Qian, Xu, Shuigang, Yang, Yaping, Piot, Benjamin A., Hu, Sheng, Taniguchi, Takashi, Watanabe, Kenji, Novoselov, Kostya S., Geim, A. K., Fal’ko, Vladimir I., and Mishchenko, Artem
- Abstract
Van der Waals assembly enables the design of electronic states in two-dimensional (2D) materials, often by superimposing a long-wavelength periodic potential on a crystal lattice using moiré superlattices1–9. This twistronics approach has resulted in numerous previously undescribed physics, including strong correlations and superconductivity in twisted bilayer graphene10–12, resonant excitons, charge ordering and Wigner crystallization in transition-metal chalcogenide moiré structures13–18and Hofstadter’s butterfly spectra and Brown–Zak quantum oscillations in graphene superlattices19–22. Moreover, twistronics has been used to modify near-surface states at the interface between van der Waals crystals23,24. Here we show that electronic states in three-dimensional (3D) crystals such as graphite can be tuned by a superlattice potential occurring at the interface with another crystal—namely, crystallographically aligned hexagonal boron nitride. This alignment results in several Lifshitz transitions and Brown–Zak oscillations arising from near-surface states, whereas, in high magnetic fields, fractal states of Hofstadter’s butterfly draw deep into the bulk of graphite. Our work shows a way in which 3D spectra can be controlled using the approach of 2D twistronics.
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- 2023
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8. Medical Students' Learning Process During Simulated Patient Consultations in Psychiatry: A Grounded Theory Study
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Piot, Marie-Aude, Pham-Scottez, Alexandra, Bazziconi, Pierre-François, Lebailly, Thibaut, Le Moal, Valérie, Kalindjian, Nina, Sulimovic, Leslie, Duriez, Philibert, Lombardi, Laura, Barbotin, Bénédicte, Vinckier, Fabien, Burn, Carine Layat, Rethans, Jan-Joost, Tesnière, Antoine, and Falissard, Bruno
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- 2023
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9. Trajectory Inference for Unraveling Dynamic Biological Processes from Raman Spectral Data
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Goffin, Nicolas, Buache, Emilie, Charpentier, Celine, Lehrter, Véronique, Morjani, Hamid, Gobinet, Cyril, and Piot, Olivier
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Cell heterogeneity is a crucial parameter for understanding the complexity of numerous biomedical issues. Trajectory inference-based approaches are recent tools developed for single-cell transcriptomics (scRNA-seq) data analysis. They aim to reconstruct evolving pathways from the variety of cell states that coexist simultaneously in a cell population. We propose to expand this concept to Raman spectroscopy, a label-free modality that probes the global molecular nature of a sample, by investigating the dynamics of adipocyte differentiation.
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- 2023
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10. Mechanical Thrombectomy Versus Best Medical Treatment in the Late Time Window in Non-DEFUSE-Non-DAWN Patients: A Multicenter Cohort Study
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Dittrich, Tolga D., Sporns, Peter B., Kriemler, Lilian F., Rudin, Salome, Nguyen, Anh, Zietz, Annaelle, Polymeris, Alexandros A., Tränka, Christopher, Thilemann, Sebastian, Wagner, Benjamin, Altersberger, Valerian L., Piot, Ines, Barinka, Filip, Müller, Susanne, Hänsel, Martin, Gensicke, Henrik, Engelter, Stefan T., Lyrer, Philippe A., Sutter, Raoul, Nickel, Christian H., Katan, Mira, Peters, Nils, Kulcsár, Zsolt, Karwacki, Grzegorz M., Pileggi, Marco, Cereda, Carlo, Wegener, Susanne, Bonati, Leo H., Fischer, Urs, Psychogios, Marios, and De Marchis, Gian Marco
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- 2023
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11. Les Jumeaux numériques en imagerie cérébrale
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Piot, E., Renard, F., and Attyé, A.
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- 2023
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12. Psychiatric Clinical Training Across Borders: Developing Virtual Communities of Practice Through International Co-constructive Patient Simulation
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Danieli, Polina Perlman, Hanson, Mark D., VanRiper, Lindy, van Hoof, Marie-José, Thomas, Isaiah, Sibeoni, Jordan, Raats, Pascal, Prins, Cecil, Porter, Sara, Piot, Marie-Aude, Nair, Bina, Mian, Irfan, Leung, Kitty, Hibbard, Kate, Billon, Gregoire, Benoit, Laelia, Baker, Jonathan D., Alleyne, Shirley, de Carvalho-Filho, Marco A., Amsalem, Doron, and Martin, Andrés
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- 2023
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13. Digital agriculture in Europe and in France: which organisations can boost adoption levels?
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Bellon-Maurel, Véronique, Piot-Lepetit, Isabelle, Lachia, Nina, and Tisseyre, Bruno
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This paper presents the way the digital transformation of the agricultural sector is implemented in Europe and in France. It describes the main European and national strategies, the structure of research and innovation initiatives, and the investment in capacity building to foster innovation, adoption and use. More specifically, the French research and innovation ecosystem on digital agriculture is described. The actors involved come from different organisations, such as research and higher educational institutes, government agencies, agricultural technology (AgTech) companies, farmer unions etc., and work together by means of associations (e.g. Robagri), networks (e.g. RMT Naexus, DigiFermes, Fermes Leader), or living labs (e.g. Occitanum) on both digital technology assessment and co-design. Additionally, support is devoted to capacity building (e.g. Le Mas numérique , Mobilab) and a better understanding of the drivers of adoption and use of digital technologies (e.g. FrOCDA). Among these various organisations, #DigitAg, the Digital Agriculture Convergence Lab, has been created to foster interdisciplinary research on digital agriculture. All these initiatives aim to use digital technologies to support the European Green Deal, Farm-to-Fork and Biodiversity strategies as well as the French orientation towards more agroecological practices for safer and more sustainable food systems. Even though this organisational ecosystem is developing fast, the objective of encouraging the coevolution of both digital and green transformations is not without challenges that still need to be overcome, either through new research, innovations, initiatives or collaborations between the actors involved.
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- 2023
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14. Intravenous Thrombolysis in Patients With Ischemic Stroke Aged ≥90 Years: A Cohort Study From the TRISP Collaboration
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Altersberger, Valerian L., Rusche, Norman, Martinez-Majander, Nicolas, Hametner, Christian, Scheitz, Jan F., Henon, Hilde, Dell’Acqua, Maria Luisa, Strambo, Davide, Stolp, Jeffrey, Heldner, Mirjam R., Grisendi, Ilaria, Jovanovic, Dejana R., Bejot, Yannick, Pezzini, Alessandro, Leker, Ronen R., Kägi, Georg, Wegener, Susanne, Cereda, Carlo W., Lindgren, Erik, Ntaios, George, Piot, Ines, Polymeris, Alexandros A., Lyrer, Philippe A., Räty, Silja, Sibolt, Gerli, Tiainen, Marjaana, Heyse, Miriam, Erdur, Hebun, Kaaouana, Olfa, Padjen, Visnja, Zedde, Marialuisa, Arnold, Marcel, Nederkoorn, Paul J., Michel, Patrik, Bigliardi, Guido, Zini, Andrea, Cordonnier, Charlotte, Nolte, Christian H., Ringleb, Peter A., Curtze, Sami, Engelter, Stefan T., and Gensicke, Henrik
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- 2022
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15. Unsupervised Feature Selection by a Genetic Algorithm for Mid-Infrared Spectral Data
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Boutegrabet, Warda, Piot, Olivier, Guenot, Dominique, and Gobinet, Cyril
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Dimensional reduction of highly multidimensional datasets such as those acquired by Fourier transform infrared spectroscopy (FTIR) is a critical step in the data analysis workflow. To achieve this goal, numerous feature selection methods have been developed and applied in a supervised context, i.e., using a priori knowledge about data usually in the form of labels for classification or quantitative values for regression. For this, genetic algorithms have been largely exploited due to their flexibility and global optimization principle. However, few applications in an unsupervised context have been reported in infrared spectroscopy. The aim of this article is to propose a new unsupervised feature selection method based on a genetic algorithm using a validity index computed from KMeans partitions as a fitness function. Evaluated on a simulated dataset and validated and tested on three real-world infrared spectroscopic datasets, our developed algorithm is able to find the spectral descriptors improving clustering accuracy and simplifying the spectral interpretation of results.
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- 2022
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16. Les enjeux de la cardiologie de demain : le livre blanc du CNP cardiovasculaire
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Villaceque, M., Piot, O., Cattan, S., Albert, F., Sabouret, P., Pradeau, V., Cohen, A., and Leclercq, C.
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- 2022
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17. A single hole spin with enhanced coherence in natural silicon
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Piot, N., Brun, B., Schmitt, V., Zihlmann, S., Michal, V. P., Apra, A., Abadillo-Uriel, J. C., Jehl, X., Bertrand, B., Niebojewski, H., Hutin, L., Vinet, M., Urdampilleta, M., Meunier, T., Niquet, Y.-M., Maurand, R., and Franceschi, S. De
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Semiconductor spin qubits based on spin–orbit states are responsive to electric field excitations, allowing for practical, fast and potentially scalable qubit control. Spin electric susceptibility, however, renders these qubits generally vulnerable to electrical noise, which limits their coherence time. Here we report on a spin–orbit qubit consisting of a single hole electrostatically confined in a natural silicon metal-oxide-semiconductor device. By varying the magnetic field orientation, we reveal the existence of operation sweet spots where the impact of charge noise is minimized while preserving an efficient electric-dipole spin control. We correspondingly observe an extension of the Hahn-echo coherence time up to 88 μs, exceeding by an order of magnitude existing values reported for hole spin qubits, and approaching the state-of-the-art for electron spin qubits with synthetic spin–orbit coupling in isotopically purified silicon. Our finding enhances the prospects of silicon-based hole spin qubits for scalable quantum information processing.
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- 2022
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18. Experimental demonstration of optical stochastic cooling
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Jarvis, J., Lebedev, V., Romanov, A., Broemmelsiek, D., Carlson, K., Chattopadhyay, S., Dick, A., Edstrom, D., Lobach, I., Nagaitsev, S., Piekarz, H., Piot, P., Ruan, J., Santucci, J., Stancari, G., and Valishev, A.
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Particle accelerators and storage rings have been transformative instruments of discovery, and, for many applications, innovations in particle-beam cooling have been a principal driver of that success1. Stochastic cooling (SC), one of the most important conceptual and technological advances in this area2–6, cools a beam through granular sampling and correction of its phase-space structure, thus bearing resemblance to a ‘Maxwell’s demon’. The extension of SC from the microwave regime up to optical frequencies and bandwidths has long been pursued, as it could increase the achievable cooling rates by three to four orders of magnitude and provide a powerful tool for future accelerators. First proposed nearly 30 years ago, optical stochastic cooling (OSC) replaces the conventional microwave elements of SC with optical-frequency analogues and is, in principle, compatible with any species of charged-particle beam7,8. Here we describe a demonstration of OSC in a proof-of-principle experiment at the Fermi National Accelerator Laboratory’s Integrable Optics Test Accelerator9,10. The experiment used 100-MeV electrons and a non-amplified configuration of OSC with a radiation wavelength of 950 nm, and achieved strong, simultaneous cooling of the beam in all degrees of freedom. This realization of SC at optical frequencies serves as a foundation for more advanced experiments with high-gain optical amplification, and advances opportunities for future operational OSC systems with potential benefit to a broad user community in the accelerator-based sciences.
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- 2022
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19. 581 Cationic liposome encapsulation enhances intracellular delivery of retinol and diffusion into skin as detected by Raman spectroscopy
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Pujos, M., Ricarte, F., Chamayou-Robert, C., Parat, M., Couret, S., Bonnet, M., Piot, O., Essendoubi, M., and Doucet, O.
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- 2024
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20. A prospective randomized study comparing two frameless immobilization systems for cranial stereotactic radiotherapy
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Callens, Dylan, Benazzouz, Chahrazad, Stessens, Lise, Piot, Wout, Nulens, An, Lambrecht, Maarten, Berkovic, Patrick, and Daisne, Jean-François
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•Encompass with Moldcare cushion validated as a safe alternative for Dual Shell Encompass system.•No significant difference in intrafractional motion.•No significant difference in patient-comfort.
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- 2024
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21. Metalloproteinase inhibition reduces AML growth, prevents stem cell loss, and improves chemotherapy effectiveness
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Pirillo, Chiara, Birch, Flora, Tissot, Floriane S., Anton, Sara Gonzalez, Haltalli, Myriam, Tini, Valentina, Kong, Isabella, Piot, Cécile, Partridge, Ben, Pospori, Constandina, Keeshan, Karen, Santamaria, Salvatore, Hawkins, Edwin, Falini, Brunangelo, Marra, Andrea, Duarte, Delfim, Lee, Chiu Fan, Roberts, Edward, and Lo Celso, Cristina
- Abstract
Acute myeloid leukemia (AML) is a blood cancer of the myeloid lineage. Its prognosis remains poor, highlighting the need for new therapeutic and precision medicine approaches. AML symptoms often include cytopenias linked to loss of healthy hematopoietic stem and progenitor cells (HSPCs). The mechanisms behind HSPC decline are complex and still poorly understood. Here, intravital microscopy (IVM) of a well-established experimental model of AML allows direct observation of the interactions between healthy and malignant cells in the bone marrow (BM), suggesting that physical dislodgment of healthy cells by AML through damaged vasculature may play an important role. Multiple matrix metalloproteinases (MMPs), known to remodel extracellular matrix, are expressed by AML cells and the BM microenvironment. We reason MMPs could be involved in cell displacement and vascular leakiness; therefore, we evaluate the therapeutic potential of MMP pharmacological inhibition using the broad-spectrum inhibitor prinomastat. IVM analyses of prinomastat-treated mice reveal reduced vascular permeability and healthy cell clusters in circulation and lower AML infiltration, proliferation, and cell migration. Furthermore, treated mice have increased retention of healthy HSPCs in the BM and increased survival following chemotherapy. Analysis of a human AML transcriptomic database reveals widespread MMP deregulation, and human AML cells show susceptibility to MMP inhibition. Overall, our results suggest that MMP inhibition could be a promising complementary therapy to reduce AML growth and limit HSPC loss and BM vascular damage caused by MLL-AF9 and possibly other AML subtypes.
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- 2022
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22. Measuring angle-resolved dynamic deformation of micromirrors with digital stroboscopic holography
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de Groot, Peter J., Leach, Richard K., Picart, Pascal, Thakkar, Pooja, Fleury, Clément, Bainschab, Markus, Sasaki, Takashi, Zauner, Markus, Holzmann, Dominik, Piot, Adrien, and Pribošek, Jaka
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- 2022
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23. How do French agri-tech start-ups contribute to the sustainability of food value chains?
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Florez, Mauro, Piot-Lepetit, Isabelle, Bourdon, Isabelle, and Gauche, Karine
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ABSTRACTThe development of digital technologies is one of the solutions being implemented to empower the food industry, especially now, when the sector is struggling to meet sustainable development goals by 2030. The attention of digital solutions has been widely given to its use at the production segment of the food value chains; that is, on-farm activities. We argue that digital technologies can enhance productivity and resilience along the entire food value chain, while increasing sustainability in this domain. Our results show complete digitalization of food value chains in France, driven by innovative start-ups, with some stages more digitalized than others. Indeed, digital technologies are shown to support the three dimensions of sustainable development goals: economic, social, and environmental. However, their benefits should be equally accessible to all actors in this field, and we therefore suggest further research.
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- 2022
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24. Low and stable HIV seroprevalence in pregnant women in Shaba province, Zaire
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Magazani, K., Laleman, G., Perriens, J.H., Kizonde, K., Mukendi, K., Mpungu, M., Badibanga, N., and Piot, P.
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Congo (Kinshasa) -- Health aspects ,HIV seroprevalence ,Pregnant women -- Health aspects ,Health - Abstract
The incidence of HIV seropositivity among pregnant women in Shaba province, Zaire appears to have remained relatively low and stable from 1989 to 1991. Among 8,725 blood donors throughout Shaba province, the incidence of HIV seropositivity was 4.6%. Of the 4,205 pregnant blood donors, 129 (3.1%) were HIV positive. No increases in the incidence of HIV infection were observed over the two years among the pregnant women or in the general population. The higher percentage of HIV infection among the general population may be explained by paid donors or donors whose relatives need blood transfusions. These donors may be at higher risk themselves for HIV infection. Results from the study also indicate that HIV has spread from urban areas to rural areas in this time period. It is not clear why the spread of HIV appears to be slower in Zaire than in other East African countries.
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- 1993
25. Tunable van Hove singularities and correlated states in twisted monolayer–bilayer graphene
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Xu, Shuigang, Al Ezzi, Mohammed M., Balakrishnan, Nilanthy, Garcia-Ruiz, Aitor, Tsim, Bonnie, Mullan, Ciaran, Barrier, Julien, Xin, Na, Piot, Benjamin A., Taniguchi, Takashi, Watanabe, Kenji, Carvalho, Alexandra, Mishchenko, Artem, Geim, A. K., Fal’ko, Vladimir I., Adam, Shaffique, Neto, Antonio Helio Castro, Novoselov, Kostya S., and Shi, Yanmeng
- Abstract
Understanding and tuning correlated states is of great interest and importance to modern condensed-matter physics. The recent discovery of unconventional superconductivity and Mott-like insulating states in magic-angle twisted bilayer graphene presents a unique platform to study correlation phenomena, in which the Coulomb energy dominates over the quenched kinetic energy as a result of hybridized flat bands. Extending this approach to the case of twisted multilayer graphene would allow even higher control over the band structure because of the reduced symmetry of the system. Here we study electronic transport properties of twisted monolayer–bilayer graphene (a bilayer on top of monolayer graphene heterostructure). We observe the formation of van Hove singularities that are highly tunable by changing either the twist angle or external electric field and can cause strong correlation effects under optimum conditions. We provide basic theoretical interpretations of the observed electronic structure.
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- 2021
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26. Automatic Identification of Paraffin Pixels on FTIR Images Acquired on FFPE Human Samples
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Boutegrabet, Warda, Guenot, Dominique, Bouché, Olivier, Boulagnon-Rombi, Camille, Marchal Bressenot, Aude, Piot, Olivier, and Gobinet, Cyril
- Abstract
The transfer of mid-infrared spectral histopathology to the clinic will be possible provided that its application in clinical practice is simple. Rapid analysis of formalin-fixed paraffin-embedded (FFPE) tissue section is thus a prerequisite. The chemical dewaxing of these samples before image acquisition used by the majority of studies is in contradiction with this principle. Fortunately, the in silico analysis of the images acquired on FFPE samples is possible using extended multiplicative signal correction (EMSC). However, the removal of pure paraffin pixels is essential to perform a relevant classification of tissue spectra. So far, this task was possible only if using manual and subjective histogram analysis. In this article, we thus propose a new automatic and multivariate methodology based on the analysis of optimized combinations of EMSC regression coefficients by validity indices and KMeans clustering to separate paraffin and tissue pixels. The validation of our method is performed using simulated infrared spectral images by measuring the Jaccard index between our partitions and the image model, with values always over 0.90 for diverse baseline complexity and signal-to-noise ratio. These encouraging results were also validated on real images by comparing our method with classical ones and by computing the Jaccard index between our partitions and the KMeans partitions obtained on the infrared image acquired on the same samples but after chemical dewaxing, with values always over 0.84.
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- 2021
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27. Evidence of Chlordecone Resurrection by Glyphosate in French West Indies
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Sabatier, Pierre, Mottes, Charles, Cottin, Nathalie, Evrard, Olivier, Comte, Irina, Piot, Christine, Gay, Bastien, Arnaud, Fabien, Lefevre, Irène, Develle, Anne-Lise, Deffontaines, Landry, Plet, Joanne, Lesueur-Jannoyer, Magalie, and Poulenard, Jérôme
- Abstract
The widespread use of pesticides in agriculture during the last several decades has contaminated soils and different Critical Zone (CZ) compartments, defined as the area extended from the top of the vegetation canopy to the groundwater table, and it integrates interactions of the atmosphere, lithosphere, biosphere, and hydrosphere. However, the long-term fate, storage, and transfer dynamics of persistent pesticides in CZ in a changing world remain poorly understood. In the French West Indies, chlordecone (CLD), a toxic organochlorine insecticide, was extensively applied to banana fields to control banana weevil from 1972 to 1993 after which it was banned. Here, to understand CZ trajectories we apply a retrospective observation based on marine sediment core analyses to monitor long-term CLD transfer, fate, and consequences in Guadeloupe and Martinique islands. Both CLD profiles show synchronous chronologies. We hypothesized that the use of glyphosate, a postemergence herbicide, from the late 1990s onward induced CZ modification with an increase in soil erosion and led to the release of the stable CLD stored in the soils of polluted fields. CLD fluxes drastically increased when glyphosate use began, leading to widespread ecosystem contamination. As glyphosate is used globally, ecotoxicological risk management strategies should consider how its application affects persistent pesticide storage in soils, transfer dynamics, and widespread contamination.
- Published
- 2021
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28. Dynamic Recrystallization Mechanisms of Nickel Niobium Alloys during Hot Working
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Matougui, Nadjoua, Fares, Mohamed Lamine, and Piot, David
- Abstract
This present work examines the influence of niobium in solid solution on the microstructural evolution of pure nickel at various deformation conditions. On this purpose, high-purity nickel and six model nickel-niobium alloys (Ni–0.01, 0.1, 1, 2, 5 and 10 wt. % Nb) were subjected to hot torsion test to large strains within the temperature range from 800 to 1000 °C at strain rates of 0.03, 0.1 and 0.3 s
– 1 . Microstructural analyses were carried out using both optical and scanning electron microscopy-based electron back-scattered diffraction technique. The overall results showed the key role played by the Nb amount when coupled with various DRX mechanisms involved, i.e. DDRX, CDRX, and GDRX with respect to the prescribed deformation conditions, in reducing grain size and retarding DRX kinetics from which the microstructures of the examined materials such as Ni 2 and 10 wt. % Nb were seen evolving in different ways. In all these deformed materials, a transition from discontinuous dynamic recrystallization to continuous dynamic recrystallization was observed at low temperature and high strain rate whereas only discontinuous dynamic recrystallization occurred at high temperature.- Published
- 2021
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29. Influence of Strain-Hardening and Dynamic Recovery on DDRX Steady State
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Montheillet, Frank and Piot, David
- Abstract
Relationships between macroscopic and microscopic constitutive parameters associated with steady state DDRX are derived for a material in which strain-hardening and dynamic recovery are described by the Yoshie-Laasraoui-Jonas equation. First examples are given for illustration.
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- 2021
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30. Comparability of Raman Spectroscopic Configurations: A Large Scale Cross-Laboratory Study
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Guo, Shuxia, Beleites, Claudia, Neugebauer, Ute, Abalde-Cela, Sara, Afseth, Nils Kristian, Alsamad, Fatima, Anand, Suresh, Araujo-Andrade, Cuauhtemoc, Aškrabić, Sonja, Avci, Ertug, Baia, Monica, Baranska, Malgorzata, Baria, Enrico, Batista de Carvalho, Luis A. E., de Bettignies, Philippe, Bonifacio, Alois, Bonnier, Franck, Brauchle, Eva Maria, Byrne, Hugh J., Chourpa, Igor, Cicchi, Riccardo, Cuisinier, Frederic, Culha, Mustafa, Dahms, Marcel, David, Catalina, Duponchel, Ludovic, Duraipandian, Shiyamala, El-Mashtoly, Samir F., Ellis, David I., Eppe, Gauthier, Falgayrac, Guillaume, Gamulin, Ozren, Gardner, Benjamin, Gardner, Peter, Gerwert, Klaus, Giamarellos-Bourboulis, Evangelos J., Gizurarson, Sveinbjorn, Gnyba, Marcin, Goodacre, Royston, Grysan, Patrick, Guntinas-Lichius, Orlando, Helgadottir, Helga, Grošev, Vlasta Mohaček, Kendall, Catherine, Kiselev, Roman, Kölbach, Micha, Krafft, Christoph, Krishnamoorthy, Sivashankar, Kubryck, Patrick, Lendl, Bernhard, Loza-Alvarez, Pablo, Lyng, Fiona M., Machill, Susanne, Malherbe, Cedric, Marro, Monica, Marques, Maria Paula M., Matuszyk, Ewelina, Morasso, Carlo Francesco, Moreau, Myriam, Muhamadali, Howbeer, Mussi, Valentina, Notingher, Ioan, Pacia, Marta Z., Pavone, Francesco S., Penel, Guillaume, Petersen, Dennis, Piot, Olivier, Rau, Julietta V., Richter, Marc, Rybarczyk, Maria Krystyna, Salehi, Hamideh, Schenke-Layland, Katja, Schlücker, Sebastian, Schosserer, Markus, Schütze, Karin, Sergo, Valter, Sinjab, Faris, Smulko, Janusz, Sockalingum, Ganesh D., Stiebing, Clara, Stone, Nick, Untereiner, Valérie, Vanna, Renzo, Wieland, Karin, Popp, Jürgen, and Bocklitz, Thomas
- Abstract
The variable configuration of Raman spectroscopic platforms is one of the major obstacles in establishing Raman spectroscopy as a valuable physicochemical method within real-world scenarios such as clinical diagnostics. For such real world applications like diagnostic classification, the models should ideally be usable to predict data from different setups. Whether it is done by training a rugged model with data from many setups or by a primary-replica strategy where models are developed on a ‘primary’ setup and the test data are generated on ‘replicate’ setups, this is only possible if the Raman spectra from different setups are consistent, reproducible, and comparable. However, Raman spectra can be highly sensitive to the measurement conditions, and they change from setup to setup even if the same samples are measured. Although increasingly recognized as an issue, the dependence of the Raman spectra on the instrumental configuration is far from being fully understood and great effort is needed to address the resulting spectral variations and to correct for them. To make the severity of the situation clear, we present a round robin experiment investigating the comparability of 35 Raman spectroscopic devices with different configurations in 15 institutes within seven European countries from the COST (European Cooperation in Science and Technology) action Raman4clinics. The experiment was developed in a fashion that allows various instrumental configurations ranging from highly confocal setups to fibre-optic based systems with different excitation wavelengths. We illustrate the spectral variations caused by the instrumental configurations from the perspectives of peak shifts, intensity variations, peak widths, and noise levels. We conclude this contribution with recommendations that may help to improve the inter-laboratory studies.
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- 2020
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31. Proposal for a standardized discharge letter after hospital stay for acute myocardial infarction
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Schiele, Francois, Lemesle, Gilles, Angoulvant, Denis, Krempf, Michel, Kownator, Serge, Cheggour, Saida, Belle, Loic, Ferrières, Jean, Bauters, Christophe, Bergerot, Cyrille, Beygui, Farzin, Boccara, Franck, Bonnefoy, Eric, Bruckert, Eric, Cayla, Guillaume, Collet, Jean-Philippe, Coste, Pierre, Descotes-Genon, Vincent, Ducrocq, Gregory, Elbaz, Meyer, Farnier, Michel, Ferrari, Emile, Guedj, Dominique, Levai, Laszlo, Mansourati, Jacques, Mansencal, Nicolas, Meneveau, Nicolas, Meune, Christophe, Morel, Olivier, Ohlmann, Patrick, Paillard, Francois, Piot, Christophe, Puymirat, Etienne, Rioufol, Gilles, Roubille, François, Sabouret, Pierre, and Teiger, Emmanuel
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In patients admitted for acute myocardial infarction, the communication and transition from specialists to primary care physicians is often delayed, and the information imparted to subsequent healthcare providers (HCPs) may be sub-optimal. A French group of cardiologists, lipidologists and diabetologists decided to establish a consensus to optimize the discharge letter after hospitalization for acute myocardial infarction. The aim is to improve both the timeframe and the quality of the content transmitted to subsequent HCPs, including information regarding baseline assessment, procedures during hospitalization, residual risk, discharge treatments, therapeutic targets and follow-up recommendations in compliance with European Society of Cardiology guidelines. A consensus was obtained regarding a template discharge letter, to be released within two days after patient’s discharge, and containing the description of the patient’s history, risk factors, acute management, risk assessment, discharge treatments and follow-up pathway. Specifically for post acute MI patients, tailored details are necessary regarding the antithrombotic regimen, lipid-lowering and anti-diabetic treatments, including therapeutic targets. Lastly, the follow-up pathway needs to be precisely mentioned in the discharge letter. Additional information such as technical descriptions, imaging, and quality indicators may be provided separately. A template for a standardized discharge letter based on 8 major headings could be useful for implementation in routine practice and help to improve the quality and timing of information transmission between HCPs after acute MI.
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- 2020
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32. Electronic phase separation in multilayer rhombohedral graphite
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Shi, Yanmeng, Xu, Shuigang, Yang, Yaping, Slizovskiy, Sergey, Morozov, Sergey V., Son, Seok-Kyun, Ozdemir, Servet, Mullan, Ciaran, Barrier, Julien, Yin, Jun, Berdyugin, Alexey I., Piot, Benjamin A., Taniguchi, Takashi, Watanabe, Kenji, Fal’ko, Vladimir I., Novoselov, Kostya S., Geim, A. K., and Mishchenko, Artem
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Of the two stable forms of graphite, hexagonal and rhombohedral, the former is more common and has been studied extensively. The latter is less stable, which has so far precluded its detailed investigation, despite many theoretical predictions about the abundance of exotic interaction-induced physics1–6. Advances in van der Waals heterostructure technology7have now allowed us to make high-quality rhombohedral graphite films up to 50 graphene layers thick and study their transport properties. Here we show that the bulk electronic states in such rhombohedral graphite are gapped8and, at low temperatures, electron transport is dominated by surface states. Because of their proposed topological nature, the surface states are of sufficiently high quality to observe the quantum Hall effect, whereby rhombohedral graphite exhibits phase transitions between a gapless semimetallic phase and a gapped quantum spin Hall phase with giant Berry curvature. We find that an energy gap can also be opened in the surface states by breaking their inversion symmetry by applying a perpendicular electric field. Moreover, in rhombohedral graphite thinner than four nanometres, a gap is present even without an external electric field. This spontaneous gap opening shows pronounced hysteresis and other signatures characteristic of electronic phase separation, which we attribute to emergence of strongly correlated electronic surface states.
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- 2020
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33. Personal recovery of young adults with severe anorexia nervosa during adolescence: a case series
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Piot, Marie-Aude, Gueguen, Juliette, Michelet, Daphné, Orri, Massimiliano, Köenig, Marie, Corcos, Maurice, Cadwallader, Jean-Sébastien, and Godart, Nathalie
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Purpose: Despite the emergence of a growing qualitative literature about the personal recovery process in mental disorders, this topic remains little understood in anorexia nervosa (AN), especially severe AN during adolescence. This cases series is a first step that aims to understand recovery after severe AN among adolescents in France, from a first-person perspective. Methods: This cases series applied the interpretative phenomenological analysis (IPA) method to data collected in semi-structured face-to-face interviews about the recovery process of five young women who had been hospitalized with severe AN 10 years earlier during adolescence. Results: A model of recovery in four stages (corseted, vulnerable, plastic, and playful) crossing seven dimensions (struggle and path of initiation; work on oneself; self-determination and help; body; family; connectedness; and timeline) emerged from the analysis. New features of the AN personal recovery process were characterized: bodily well-being and pleasure of body; stigmatization; the role of the group; relation to time; and importance of narratives. We suggest a new shape to model the AN recovery process, one that suggests several tipping points. Recruitment must now be widened to different AN contexts. Conclusions: The personal recovery paradigm may provide a new approach to care, complementary to medical paradigm. Registration of clinical trial: No. NCT03712384. Our study was purely observational, without assignment of medical intervention. As a consequence, this clinical trial was registered retrospectively. Level of evidence: Level V, descriptive study.
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- 2020
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34. Surface Enhanced Raman Spectroscopy for Quantitative Analysis: Results of a Large-Scale European Multi-Instrument Interlaboratory Study
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Fornasaro, Stefano, Alsamad, Fatima, Baia, Monica, Batista de Carvalho, Luís A. E., Beleites, Claudia, Byrne, Hugh J., Chiadò, Alessandro, Chis, Mihaela, Chisanga, Malama, Daniel, Amuthachelvi, Dybas, Jakub, Eppe, Gauthier, Falgayrac, Guillaume, Faulds, Karen, Gebavi, Hrvoje, Giorgis, Fabrizio, Goodacre, Royston, Graham, Duncan, La Manna, Pietro, Laing, Stacey, Litti, Lucio, Lyng, Fiona M., Malek, Kamilla, Malherbe, Cedric, Marques, Maria P. M., Meneghetti, Moreno, Mitri, Elisa, Mohaček-Grošev, Vlasta, Morasso, Carlo, Muhamadali, Howbeer, Musto, Pellegrino, Novara, Chiara, Pannico, Marianna, Penel, Guillaume, Piot, Olivier, Rindzevicius, Tomas, Rusu, Elena A., Schmidt, Michael S., Sergo, Valter, Sockalingum, Ganesh D., Untereiner, Valérie, Vanna, Renzo, Wiercigroch, Ewelina, and Bonifacio, Alois
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Surface-enhanced Raman scattering (SERS) is a powerful and sensitive technique for the detection of fingerprint signals of molecules and for the investigation of a series of surface chemical reactions. Many studies introduced quantitative applications of SERS in various fields, and several SERS methods have been implemented for each specific application, ranging in performance characteristics, analytes used, instruments, and analytical matrices. In general, very few methods have been validated according to international guidelines. As a consequence, the application of SERS in highly regulated environments is still considered risky, and the perception of a poorly reproducible and insufficiently robust analytical technique has persistently retarded its routine implementation. Collaborative trials are a type of interlaboratory study (ILS) frequently performed to ascertain the quality of a single analytical method. The idea of an ILS of quantification with SERS arose within the framework of Working Group 1 (WG1) of the EU COST Action BM1401 Raman4Clinics in an effort to overcome the problematic perception of quantitative SERS methods. Here, we report the first interlaboratory SERS study ever conducted, involving 15 laboratories and 44 researchers. In this study, we tried to define a methodology to assess the reproducibility and trueness of a quantitative SERS method and to compare different methods. In our opinion, this is a first important step toward a “standardization” process of SERS protocols, not proposed by a single laboratory but by a larger community.
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- 2020
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35. Strong Grain Boundary Passivation Effect of Coevaporated Dopants Enhances the Photoemission of Lead Halide Perovskites
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Kalluvila Justin, Isabella A., Tiede, David O., Piot, Manuel, Forzatti, Michele, Roldán-Carmona, Cristina, Galisteo-López, Juan F., Míguez, Hernán, and Bolink, Henk J.
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Herein, we demonstrate that coevaporated dopants provide a means to passivate buried interfacial defects occurring at perovskite grain boundaries in evaporated perovskite thin films, thus giving rise to an enhanced photoluminescence. By means of an extensive photophysical characterization, we provide experimental evidence that indicate that the codopant acts mainly at the grain boundaries. They passivate interfacial traps and prevent the formation of photoinduced deep traps. On the other hand, the presence of an excessive amount of organic dopant can lead to a barrier for carrier diffusion. Hence, the passivation process demands a proper balance between the two effects. Our analysis on the role of the dopant, performed under different excitation regimes, permits evaluation of the performance of the material under conditions more adapted to photovoltaic or light emitting applications. In this context, the approach taken herein provides a screening method to evaluate the suitability of a passivating strategy prior to its incorporation into a device.
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- 2024
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36. Bloc auriculo-ventriculaire à l’effort
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Mahieddine, H. and Piot, O.
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- 2024
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37. WITHDRAWAL: Prediction of Nonarrhythmic Mortality in Primary Prevention Implantable Cardioverter-Defibrillator Patients With Ischemic and Nonischemic Cardiomyopathy
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Providência, Rui, Boveda, Serge, Lambiase, Pier, Defaye, Pascal, Algalarrondo, Vincent, Sadoul, Nicolas, Piot, Olivier, Klug, Didier, Perier, Marie-Cecile, Bouzeman, Abdeslam, Gras, Daniel, Fauchier, Laurent, Bordachar, Pierre, Babuty, Dominique, Deharo, Jean-Claude, Leclercq, Christophe, and Marijon, Eloi
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This article has been withdrawn because it is a duplicate. The correct published version of the article can be found at http://dx.doi.org/10.1016/j.jacep.2015.01.004. The Publisher apologizes for any inconvenience this may cause.
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- 2024
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38. An adapted version of Kluft's Dimensions of therapeutic movement instrument (DTMI)
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Piedfort-Marin, Olivier, Wisler, Deborah, Spagnoli, Danièle, and Piot, Marie-Eve
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The Dimensions of therapeutic movement instrument (DTMI) was developed by Kluft with the aim to assess the evolution of the psychotherapy of patients suffering from severe dissociative disorders. The DTMI consists of the monthly evaluation of 12 dimensions with predefined descriptive items.
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- 2024
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39. Version française adaptée de l’Échelle d’évaluation de l’avancement de la psychothérapie (EEAP/DTMI)
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Piedfort-Marin, Olivier, Wisler, Deborah, Piot, Marie-Eve, and Spagnoli, Danièle
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Le DTMI (Dimensions of Therapeutic Movement Instrument ; Échelle d’évaluation de l’avancement de la psychothérapie – EEAP) a été développé par Kluft dans le but d’évaluer l’évolution de la psychothérapie des patients souffrant de troubles dissociatifs sévères. L’EEAP consiste en l’évaluation mensuelle de 12 dimensions, chacune avec des items descriptifs prédéfinis.
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- 2024
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40. Carpal Tunnel Syndrome: A New Adverse Effect of Immune Checkpoint Inhibitors, 11 Cases
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Lechevalier, Diane, Denis, Daphné, Le Corre, Yannick, Heidelberger, Valentine, Brunet-Possenti, Florence, Longvert, Christine, Piot, Jean M., Maillard, Hervé, and Beneton, Nathalie
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This study aims at reporting 11 cases of carpal tunnel syndrome (CTS) occurring in patients on immunotherapy. The increasing use of immune checkpoint inhibitors in oncodermatology is associated with the appearance of immunologic adverse effects linked to nonspecific stimulation of the immune system. CTS has not been reported in this context. A retrospective multicenter review was performed on CTSs occurring on immunotherapy and confirmed with electroneuromyography. Data were collated from patients’ files. Most of the time, CTS was severe, bilateral, with a motor deficit and confirmed axonal damage on electroneuromyography. In 4 cases, it was associated with rheumatological adverse effects (arthralgia/inflammatory synovitis). The most effective treatment appeared to be general corticosteroid therapy, even at low doses (<15 mg/d), or surgery. An imputability of the CTS of these patients to immunotherapy was considered due to the unusual intensity of the symptoms and the absence of other predisposing factors (diabetes and dysthyroidism well-controlled). Its combination with other immunologic adverse effects and the efficacy of general corticosteroid therapy suggests an immunologic origin. CTS is probably an immunologic adverse effect of immunotherapy. It is often severe or misleading in presentation and affects quality of life. The recognition of this adverse effect should make it possible to provide patients with appropriate care.
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- 2024
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41. Short-term effects of a simulation-based training program on suicide risk assessment and intervention for first-year psychiatry residents
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Richard, Océane, Piot, Marie-Aude, and Jollant, Fabrice
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Adequate training of mental health professionals in suicide risk assessment and intervention is crucial. Simulation-based education is a relevant method to acquire competences for challenging health interventions. Here, we aimed to evaluate the effects of a simulation-based training program on first-year psychiatry residents’ skills, knowledge, attitudes and satisfaction.
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- 2024
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42. Comprehensive Characterization of the Interaction between Pulsed Electric Fields and Live Cells by Confocal Raman Microspectroscopy
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Azan, Antoine, Untereiner, Valérie, Descamps, Lucie, Merla, Caterina, Gobinet, Cyril, Breton, Marie, Piot, Olivier, and Mir, Lluis M.
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This study reports a comprehensive analysis of the effect of 100 μs electric pulses on the biochemical composition of live cells using a label-free approach, confocal Raman microspectroscopy. We investigated different regions of interest around the nucleus of the cells and the dose–effect relationship related to different electric pulse parameters. We also extended the study to another cell type. Membrane resealing was monitored by pulsing the cells in reversible or irreversible electropermeabilization condition at different temperatures. Our results confirmed a previous publication showing that proteins and lipids were highly impacted by the delivery of electric pulses. These chemical changes were similar in different locations around the cell nucleus. By sweeping the field magnitude, the number of electric pulses, or their repetition rate, the Raman signatures of live cells appeared to be related to the electropermeabilization state, verified by Yo-Pro-1 uptake. We also demonstrated that the chemical changes in the Raman signatures were cell-dependent even if common features were noticed between the two cell types used.
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- 2024
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43. La spectroscopie vibrationnelle infrarouge en mode polarisé pour imager l’orientation des fibres de collagène dans le contexte du vieillissement cutané
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Essendoubi, Mohammed, Gobinet, Cyril, Manfait, Michel, Piot, Olivier, Essendoubi, Mohammed, Gobinet, Cyril, Manfait, Michel, and Piot, Olivier
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La peau est un organe multifonctionnel dont la principale fonction est un rôle protecteur de l’organisme contre les agressions externes. Le collagène de type I est le constituant majeur du derme ; au cours du vieillissement chronologique de la peau, les fibres de collagène subissent des altérations structurales entraînant des modifications morphologiques et fonctionnelles importantes [1-5]. Nous nous sommes intéressés aux changements d’orientation que pouvaient subir les fibres de collagène pendant le vieillissement chronologique de la peau.
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- 2017
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44. À la recherche de l’ultime atome
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Stodel, Christelle, Boilley, David, Piot, Julien, Ackermann, Dieter, Stodel, Christelle, Boilley, David, Piot, Julien, and Ackermann, Dieter
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La dernière ligne du tableau périodique de Mendeleïev est maintenant complète et l’élément le plus lourd, l’oganesson, compte 118 protons. Il s’agit là de la limite atteinte avec les technologies actuelles, mais pas la limite d’existence des éléments chimiques.
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- 2017
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45. Aide au diagnostic des proteinopathies liées aux demences fronto-temporales basée sur des patterns d'atrophie corticale en irm morphologique
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Attye, Arnaud, Renard, Felix, Piot, Elodie, Calamante, Fernando, Hwang, Yun, Krainik, Alexandre, and Piguet, Olivier
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Les démences fronto-temporales (DFT) sont des maladies rares et hétérogènes cliniquement, qui sont liées soit à un dépôt de protéines Tau dans le cerveau, soit à un dépôt de protéines TDP43. A l'heure actuelle, seuls les tests de dépistage génétique permettent d'obtenir inconstamment des arguments en faveur d'un type de protéine cérébrale causale. Nous testons ici l'intérêt d'une intelligence artificielle (IA) non supervisée pour différencier les deux sous-types d'atteinte biologique, à partir d'IRM en pondération T1.
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- 2023
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46. Immunization: vital progress, unfinished agenda
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Piot, Peter, Larson, Heidi J., O’Brien, Katherine L., N’kengasong, John, Ng, Edmond, Sow, Samba, and Kampmann, Beate
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Vaccination against infectious diseases has changed the future of the human species, saving millions of lives every year, both children and adults, and providing major benefits to society as a whole. Here we show, however, that national and sub-national coverage of vaccination varies greatly and major unmet needs persist. Although scientific progress opens exciting perspectives in terms of new vaccines, the pathway from discovery to sustainable implementation can be long and difficult, from the financing, development and licensing to programme implementation and public acceptance. Immunization is one of the best investments in health and should remain a priority for research, industry, public health and society.
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- 2019
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47. Magnetospectroscopy of double HgTe/CdHgTe QWs with inverted band structure in high magnetic fields up to 30 T
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Bovkun, L.S., Ikonnikov, A.V., Aleshkin, V.Ya., Maremyanin, K.V., Mikhailov, N.N., Dvoretskii, S.A., Krishtopenko, S.S., Teppe, F., Piot, B.A., Potemski, M., Orlita, M., and Gavrilenko, V.I.
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- 2019
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48. Mapping HIV prevalence in sub-Saharan Africa between 2000 and 2017
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Dwyer-Lindgren, Laura, Cork, Michael A., Sligar, Amber, Steuben, Krista M., Wilson, Kate F., Provost, Naomi R., Mayala, Benjamin K., VanderHeide, John D., Collison, Michael L., Hall, Jason B., Biehl, Molly H., Carter, Austin, Frank, Tahvi, Douwes-Schultz, Dirk, Burstein, Roy, Casey, Daniel C., Deshpande, Aniruddha, Earl, Lucas, El Bcheraoui, Charbel, Farag, Tamer H., Henry, Nathaniel J., Kinyoki, Damaris, Marczak, Laurie B., Nixon, Molly R., Osgood-Zimmerman, Aaron, Pigott, David, Reiner, Robert C., Ross, Jennifer M., Schaeffer, Lauren E., Smith, David L., Davis Weaver, Nicole, Wiens, Kirsten E., Eaton, Jeffrey W., Justman, Jessica E., Opio, Alex, Sartorius, Benn, Tanser, Frank, Wabiri, Njeri, Piot, Peter, Murray, Christopher J. L., and Hay, Simon I.
- Abstract
HIV/AIDS is a leading cause of disease burden in sub-Saharan Africa. Existing evidence has demonstrated that there is substantial local variation in the prevalence of HIV; however, subnational variation has not been investigated at a high spatial resolution across the continent. Here we explore within-country variation at a 5 × 5-km resolution in sub-Saharan Africa by estimating the prevalence of HIV among adults (aged 15–49 years) and the corresponding number of people living with HIV from 2000 to 2017. Our analysis reveals substantial within-country variation in the prevalence of HIV throughout sub-Saharan Africa and local differences in both the direction and rate of change in HIV prevalence between 2000 and 2017, highlighting the degree to which important local differences are masked when examining trends at the country level. These fine-scale estimates of HIV prevalence across space and time provide an important tool for precisely targeting the interventions that are necessary to bringing HIV infections under control in sub-Saharan Africa.
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- 2019
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49. Dimensional reduction, quantum Hall effect and layer parity in graphite films
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Yin, Jun, Slizovskiy, Sergey, Cao, Yang, Hu, Sheng, Yang, Yaping, Lobanova, Inna, Piot, Benjamin A., Son, Seok-Kyun, Ozdemir, Servet, Taniguchi, Takashi, Watanabe, Kenji, Novoselov, Kostya S., Guinea, Francisco, Geim, A. K., Fal’ko, Vladimir, and Mishchenko, Artem
- Abstract
The quantum Hall effect (QHE) originates from discrete Landau levels forming in a two-dimensional electron system in a magnetic field1. In three dimensions, the QHE is forbidden because the third dimension spreads Landau levels into overlapping bands, destroying the quantization. Here we report the QHE in graphite crystals that are up to hundreds of atomic layers thick, a thickness at which graphite was believed to behave as a normal, bulk semimetal2. We attribute this observation to a dimensional reduction of electron dynamics in high magnetic fields, such that the electron spectrum remains continuous only in the field direction, and only the last two quasi-one-dimensional Landau bands cross the Fermi level3,4. Under these conditions, the formation of standing waves in sufficiently thin graphite films leads to a discrete spectrum allowing the QHE. Despite the large thickness, we observe differences between crystals with even and odd numbers of graphene layers. Films with odd layer numbers show reduced QHE gaps, as compared to films of similar thicknesses but with even numbers because the latter retain the inversion symmetry characteristic of bilayer graphene5,6. We also observe clear signatures of electron–electron interactions including the fractional QHE below 0.5 K.
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- 2019
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50. Determining Interaction Enhanced Valley Susceptibility in Spin-Valley-Locked MoS2
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Lin, Jiangxiazi, Han, Tianyi, Piot, Benjamin A., Wu, Zefei, Xu, Shuigang, Long, Gen, An, Liheng, Cheung, Patrick, Zheng, Peng-Peng, Plochocka, Paulina, Dai, Xi, Maude, Duncan K., Zhang, Fan, and Wang, Ning
- Abstract
Two-dimensional transition metal dichalcogenides (TMDCs) are recently emerged electronic systems with various novel properties, such as spin-valley locking, circular dichroism, valley Hall effect, and superconductivity. The reduced dimensionality and large effective masses further produce unconventional many-body interaction effects. Here we reveal strong interaction effects in the conduction band of MoS2by transport experiment. We study the massive Dirac electron Landau levels (LL) in high-quality MoS2samples with field-effect mobilities of 24 000 cm2/(V·s) at 1.2 K. We identify the valley-resolved LLs and low-lying polarized LLs using the Lifshitz–Kosevitch formula. By further tracing the LL crossings in the Landau fan diagram, we unambiguously determine the density-dependent valley susceptibility and the interaction enhanced g-factor from 12.7 to 23.6. Near integer ratios of Zeeman-to-cyclotron energies, we discover LL anticrossings due to the formation of quantum Hall Ising ferromagnets, the valley polarizations of which appear to be reversible by tuning the density or an in-plane magnetic field. Our results provide evidence for many-body interaction effects in the conduction band of MoS2and establish a fertile ground for exploring strongly correlated phenomena of massive Dirac electrons.
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- 2019
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