Search

Your search keyword '"K. Andre"' showing total 864 results
Start Over Author "K. Andre"
864 results on '"K. Andre"'

51. Room-temperature perpendicular magnetization switching through giant spin-orbit torque from sputtered BixSe(1-x) topological insulator material

Author

DC, Mahendra, Jamali, Mahdi, Chen, Jun-Yang, Hickey, Danielle Reifsnyder, Zhang, Delin, Zhao, Zhengyang, Li, Hongshi, Quarterman, P., Lv, Yang, Li, Mo, Mkhoyan, K. Andre, and Wang, Jian-Ping

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The spin-orbit torque (SOT) arising from materials with large spin-orbit coupling promises a path for ultra-low power and fast magnetic-based storage and computational devices. We investigated the SOT from magnetron-sputtered BixSe(1-x) thin films in BixSe(1-x)/CoFeB heterostructures by using a dc planar Hall method. Remarkably, the spin Hall angle (SHA) was found to be as large as 18.83, which is the largest ever reported at room temperature (RT). Moreover, switching of a perpendicular CoFeB multilayer using SOT from the BixSe(1-x) has been observed with the lowest-ever switching current density reported in a bilayer system: 2.3 * 105 A/cm2 at RT. The giant SHA, smooth surface, ease of growth of the films on silicon substrate, successful growth and switching of a perpendicular CoFeB multilayer on BixSe(1-x) film opens a path for use of BixSe(1-x) topological insulator (TI) material as a spin-current generator in SOT-based memory and logic devices., Comment: 14 pages, 3 figures

Published
2017
Full Text
View/download PDF

52. Multifunctional 2D FETs exploiting incipient ferroelectricity in freestanding SrTiO3 nanomembranes at sub-ambient temperatures.

Author

Sen, Dipanjan, Ravichandran, Harikrishnan, Das, Mayukh, Venkatram, Pranavram, Choo, Sooho, Varshney, Shivasheesh, Zhang, Zhiyu, Sun, Yongwen, Shah, Jay, Subbulakshmi Radhakrishnan, Shiva, Saha, Akash, Hazra, Sankalpa, Chen, Chen, Redwing, Joan M., Mkhoyan, K. Andre, Gopalan, Venkatraman, Yang, Yang, Jalan, Bharat, and Das, Saptarshi

Subjects
FIELD-effect transistors, ELECTRONIC equipment, LOW temperatures, NANOTECHNOLOGY, FERROELECTRIC crystals
Abstract

Incipient ferroelectricity bridges traditional dielectrics and true ferroelectrics, enabling advanced electronic and memory devices. Firstly, we report incipient ferroelectricity in freestanding SrTiO3 nanomembranes integrated with monolayer MoS2 to create multifunctional devices, demonstrating stable ferroelectric order at low temperatures for cryogenic memory devices. Our observation includes ultra-fast polarization switching (~10 ns), low switching voltage (<6 V), over 10 years of nonvolatile retention, 100,000 endurance cycles, and 32 conductance states (5-bit memory) in SrTiO3-gated MoS2 transistors at 15 K and up to 100 K. Additionally, we exploit room-temperature weak polarization switching, a feature of incipient ferroelectricity, to construct a physical reservoir for pattern recognition. Our results showcase the potential of utilizing perovskite material properties enabled by advancements in freestanding film growth and heterogeneous integration, for diverse functional applications. Notably, the low 180 °C thermal budget for fabricating the 3D-SrTiO3/2D-MoS2 device stack enables the integration of diverse materials into silicon complementary metal-oxide-semiconductor technology, addressing challenges in compute-in-memory and neuromorphic applications. Sen et al. report the stacking of a perovskite incipient ferroelectric nanomembrane with atomically thin 2D material for a back-end-of-line compatible ferroelectric-like field effect transistors, functioning as a cryogenic memory at 15 K and as an inference engine at room temperature. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

55. Room-temperature valence transition in a strain-tuned perovskite oxide

Author

Chaturvedi, Vipul, Ghosh, Supriya, Gautreau, Dominique, Postiglione, William M., Dewey, John E., Quarterman, Patrick, Balakrishnan, Purnima P., Kirby, Brian J., Zhou, Hua, Cheng, Huikai, Huon, Amanda, Charlton, Timothy, Fitzsimmons, Michael R., Korostynski, Caroline, Jacobson, Andrew, Figari, Lucca, Barriocanal, Javier Garcia, Birol, Turan, Mkhoyan, K. Andre, and Leighton, Chris

Published
2022
Full Text
View/download PDF

56. Electronic structure of BaSnO3 investigated by high-energy-resolution electron energy-loss spectroscopy and ab initio calculations

Author

Yun, Hwanhui, Topsakal, Mehmet, Prakash, Abhinav, Ganguly, Koustav, Leighton, Chris, Jalan, Bharat, Wentzcovitch, Renata M., Mkhoyan, K. Andre, and Jeong, Jong Seok

Subjects
Condensed Matter - Materials Science
Abstract

There has been growing interest in perovskite BaSnO3 due to its desirable properties for oxide electronic devices including high electron mobility at room temperature and optical transparency. As these electronic and optical properties originate largely from the electronic structure of the material, here the basic electronic structure of epitaxially-grown BaSnO3 films is studied using high-energy-resolution electron energy-loss spectroscopy in a transmission electron microscope and ab initio calculations. This study provides a detailed description of the dielectric function of BaSnO3, including the energies of bulk plasmon excitations and critical interband electronic transitions, the band structure and partial densities of states, the measured band gap, and more. To make the study representative of a variety of deposition methods, results from BaSnO3 films grown by both hybrid molecular beam epitaxy and high pressure oxygen sputter deposition are reported., Comment: 23 pages, 7 figures, 3 tables

Published
2016
Full Text
View/download PDF

57. A New Line Defect in NdTiO3 Perovskite

Author

Jeong, Jong Seok, Topsakal, Mehmet, Xu, Peng, Jalan, Bharat, Wentzcovitch, Renata M., and Mkhoyan, K. Andre

Subjects
Condensed Matter - Materials Science
Abstract

Perovskite oxides form an eclectic class of materials owing to their structural flexibility in accommodating cations of different sizes and valences. They host well known point and planar defects, but so far no line defect has been identified other than dislocations. Using analytical scanning transmission electron microscopy (STEM) and ab initio calculations we have detected and characterized the atomic and electronic structures of a novel line defect in NdTiO3 perovskite. It appears in STEM images as a perovskite cell rotated by 45 degrees. It consists of self-organized Ti-O vacancy lines replaced by Nd columns surrounding a central Ti-O octahedral chain containing Ti4+ ions, as opposed to Ti3+ in the host. The distinct Ti valence in this line defect introduces the possibility of engineering exotic conducting properties in a single preferred direction and tailoring novel desirable functionalities in this Mott insulator., Comment: 24 pages, 5 figures

Published
2016
Full Text
View/download PDF

58. Mapping the chemical potential dependence of current-induced spin polarization in a topological insulator

Author

Lee, Joon Sue, Richardella, Anthony, Hickey, Danielle Reifsnyder, Mkhoyan, K. Andre, and Samarth, Nitin

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We report electrical measurements of the current-induced spin polarization of the surface current in topological insulator devices where contributions from bulk and surface conduction can be disen- tangled by electrical gating. The devices use a ferromagnetic tunnel junction (permalloy/Al2O3) as a spin detector on a back-gated (Bi,Sb)2Te3 channel. We observe hysteretic voltage signals as the magnetization of the detector ferromagnet is switched parallel or anti-parallel to the spin polariza- tion of the surface current. The amplitude of the detected voltage change is linearly proportional to the applied DC bias current in the (Bi,Sb)2Te3 channel. As the chemical potential is tuned from the bulk bands into the surface state band, we observe an enhancement of the spin-dependent voltages up to 300% within the range of the electrostatic gating. Using a simple model, we extract the spin polarization near charge neutrality (i.e. the Dirac point).

Published
2015
Full Text
View/download PDF

68. Uncovering Atomic Migrations Behind Magnetic Tunnel Junction Breakdown

Author

Yun, Hwanhui, Lyu, Deyuan, Lv, Yang, Zink, Brandon R., Khanal, Pravin, Zhou, Bowei, Wang, Wei-Gang, Wang, Jian-Ping, and Mkhoyan, K. Andre

Abstract

As advances in computing technology increase demand for efficient data storage solutions, spintronic magnetic tunnel junction (MTJ)-based magnetic random-access memory (MRAM) devices emerge as promising alternatives to traditional charge-based memory devices. Successful applications of such spintronic devices necessitate understanding not only their ideal working principles but also their breakdown mechanisms. Employing an in situ electrical biasing system, atomic-resolution scanning transmission electron microscopy (STEM) reveals two distinct breakdown mechanisms. Soft breakdown occurs at relatively low electric currents due to electromigration, wherein restructuring of MTJ core layers forms ultrathin regions in the dielectric MgO layer and edge conducting paths, reducing device resistance. Complete breakdown occurs at relatively high electric currents due to a combination of joule heating and electromigration, melting MTJ component layers at temperatures below their bulk melting points. Time-resolved, atomic-scale STEM studies of functional devices provide insight into the evolution of structure and composition during device operation, serving as an innovative experimental approach for a wide variety of electronic devices.

Published
2024
Full Text
View/download PDF

73. Epitaxial growth and characterization of Bi1−xSbx thin films on (0001) sapphire substrates.

Author

Huang, Yu-Sheng, Islam, Saurav, Ou, Yongxi, Ghosh, Supriya, Richardella, Anthony, Mkhoyan, K. Andre, and Samarth, Nitin

Subjects
THIN films, SAPPHIRES, SCANNING transmission electron microscopy, MOLECULAR beam epitaxy, EPITAXY, ATOMIC force microscopy, BUFFER layers
Abstract

We report the molecular beam epitaxy of Bi1−xSbx thin films (0 ≤ x ≤ 1) on sapphire (0001) substrates using a thin (Bi,Sb)2Te3 buffer layer. The characterization of the films using reflection high energy diffraction, x-ray diffraction, atomic force microscopy, and scanning transmission electron microscopy reveals the epitaxial growth of films of reasonable structural quality. This is further confirmed via x-ray diffraction pole figures that determine the epitaxial registry between the thin film and the substrate. We further investigate the microscopic structure of thin films via Raman spectroscopy, demonstrating how the vibrational modes vary as the composition changes and discussing the implications for the crystal structure. We also characterize the samples using electrical transport measurements. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

80. Robust negative longitudinal magnetoresistance and spin–orbit torque in sputtered Pt3Sn and Pt3SnxFe1-x topological semimetal

Author

Zhang, Delin, primary, Jiang, Wei, additional, Yun, Hwanhui, additional, Benally, Onri Jay, additional, Peterson, Thomas, additional, Cresswell, Zach, additional, Fan, Yihong, additional, Lv, Yang, additional, Yu, Guichuan, additional, Barriocanal, Javier Garcia, additional, Swatek, Przemyslaw Wojciech, additional, Mkhoyan, K. Andre, additional, Low, Tony, additional, and Wang, Jian-Ping, additional

Published
2023
Full Text
View/download PDF

82. Engineering metal oxidation using epitaxial strain

Author

Sreejith Nair, Zhifei Yang, Dooyong Lee, Silu Guo, Jerzy T. Sadowski, Spencer Johnson, Abdul Saboor, Yan Li, Hua Zhou, Ryan B. Comes, Wencan Jin, K. Andre Mkhoyan, Anderson Janotti, and Bharat Jalan

Subjects
Biomedical Engineering, General Materials Science, Bioengineering, Electrical and Electronic Engineering, Condensed Matter Physics, Atomic and Molecular Physics, and Optics
Published
2023
Full Text
View/download PDF

84. External validation of the PAGE-B score for HCC risk prediction in people living with HIV/HBV coinfection

Author

Bernard Surial, Adrià Ramírez Mena, Marie Roumet, Andreas Limacher, Colette Smit, Olivier Leleux, Amanda Mocroft, Marc van der Valk, Fabrice Bonnet, Lars Peters, Jürgen K. Rockstroh, Huldrych F. Günthard, Annalisa Berzigotti, Andri Rauch, Gilles Wandeler, I. Abela, K. Aebi-Popp, A. Anagnostopoulos, M. Battegay, E. Bernasconi, D.L. Braun, H.C. Bucher, A. Calmy, M. Cavassini, A. Ciuffi, G. Dollenmaier, M. Egger, L. Elzi, J. Fehr, J. Fellay, H. Furrer, C.A. Fux, H.F. Günthard, A. Hachfeld, D. Haerry, B. Hasse, H.H. Hirsch, M. Hoffmann, I. Hösli, M. Huber, D. Jackson-Perry, C.R. Kahlert, L. Kaiser, O. Keiser, T. Klimkait, R.D. Kouyos, H. Kovari, K. Kusejko, N. Labhardt, K. Leuzinger, Martinez de Tejada B, C. Marzolini, K.J. Metzner, N. Müller, J. Nemeth, D. Nicca, J. Notter, P. Paioni, G. Pantaleo, M. Perreau, A. Rauch, L. Salazar-Vizcaya, P. Schmid, R. Speck, M. Stöckle, P. Tarr, A. Trkola, G. Wandeler, M. Weisser, S. Yerly, M. van der Valk, S.E. Geerlings, A. Goorhuis, V.C. Harris, J.W. Hovius, B. Lempkes, F.J.B. Nellen, T. van der Poll, J.M. Prins, V. Spoorenberg, M. van Vugt, W.J. Wiersinga, F.W.M.N. Wit, C. Bruins, J. van Eden, I.J. Hylkema-van den Bout, A.M.H. van Hes, F.J.J. Pijnappel, S.Y. Smalhout, A.M. Weijsenfeld, N.K.T. Back, B. Berkhout, M.T.E. Cornelissen, R. van Houdt, M. Jonges, S. Jurriaans, C.J. Schinkel, K.C. Wolthers, H.L. Zaaijer, E.J.G. Peters, M.A. van Agtmael, R.S. Autar, M. Bomers, K.C.E. Sigaloff, M. Heitmuller, L.M. Laan, M. van den Berge, A. Stegeman, S. Baas, L. Hage de Looff, A. van Arkel, J. Stohr, B. Wintermans, M.J.H. Pronk, H.S.M. Ammerlaan, E.S. de Munnik, B. Deiman, A.R. Jansz, V. Scharnhorst, J. Tjhie, M.C.A. Wegdam, A. van Eeden, E. Hoornenborg, J. Nellen, W. Alers, L.J.M. Elsenburg, H. Nobel, M.E.E. van Kasteren, M.A.H. Berrevoets, A.E. Brouwer, B.A.F.M. de Kruijf-van de Wiel, A. Adams, M. Pawels-van Rijkevoorsel, A.G.M. Buiting, J.L. Murck, C. Rokx, A.A. Anas, H.I. Bax, E.C.M. van Gorp, M. de Mendonça Melo, E. van Nood, J.L. Nouwen, B.J.A. Rijnders, C.A.M. Schurink, L. Slobbe, T.E.M.S. de Vries-Sluijs, N. Bassant, J.E.A. van Beek, M. Vriesde, L.M. van Zonneveld, J. de Groot, J.J.A. van Kampen, M.P.G. Koopmans, J.C. Rahamat-Langendoen, J. Branger, R.A. Douma, A.S. Cents-Bosma, C.J.H.M. Duijf-van de Ven, E.F. Schippers, C. van Nieuwkoop, J. Geilings, S. van Winden, G. van der Hut, N.D. van Burgel, E.M.S. Leyten, L.B.S. Gelinck, F. Mollema, G.S. Wildenbeest, T. Nguyen, P.H.P. Groeneveld, J.W. Bouwhuis, A.J.J. Lammers, A.G.W. van Hulzen, S. Kraan, M.S.M. Kruiper, G.L. van der Bliek, P.C.J. Bor, S.B. Debast, G.H.J. Wagenvoort, A.H.E. Roukens, M.G.J. de Boer, H. Jolink, M.M.C. Lambregts, H. Scheper, W. Dorama, N. van Holten, E.C.J. Claas, E. Wessels, J.G. den Hollander, R. El Moussaoui, K. Pogany, C.J. Brouwer, D. Heida-Peters, E. Mulder, J.V. Smit, D. Struik-Kalkman, T. van Niekerk, O. Pontesilli, C. van Tienen, S.H. Lowe, A.M.L. Oude Lashof, D. Posthouwer, M.E. van Wolfswinkel, R.P. Ackens, K. Burgers, M. Elasri, J. Schippers, T.R.A. Havenith, M. van Loo, M.G.A. van Vonderen, L.M. Kampschreur, M.C. van Broekhuizen, null S, null Faber, A. Al Moujahid, G.J. Kootstra, C.E. Delsing, M. van der Burg-van de Plas, L. Scheiberlich, W. Kortmann, G. van Twillert, R. Renckens, J. Wagenaar, D. Ruiter-Pronk, F.A. van Truijen-Oud, J.W.T. Cohen Stuart, M. Hoogewerf, W. Rozemeijer, J.C. Sinnige, K. Brinkman, G.E.L. van den Berk, K.D. Lettinga, M. de Regt, W.E.M. Schouten, J.E. Stalenhoef, J. Veenstra, S.M.E. Vrouenraets, H. Blaauw, G.F. Geerders, M.J. Kleene, M. Knapen, M. Kok, I.B. van der Meché, A.J.M. Toonen, S. Wijnands, E. Wttewaal, D. Kwa, T.J.W. van de Laar, R. van Crevel, K. van Aerde, A.S.M. Dofferhoff, S.S.V. Henriet, H.J.M. ter Hofstede, J. Hoogerwerf, O. Richel, M. Albers, K.J.T. Grintjes-Huisman, M. de Haan, M. Marneef, M. McCall, D. Burger, E.H. Gisolf, M. Claassen, R.J. Hassing, G. ter Beest, P.H.M. van Bentum, M. Gelling, Y. Neijland, C.M.A. Swanink, M. Klein Velderman, S.F.L. van Lelyveld, R. Soetekouw, L.M.M. van der Prijt, J. van der Swaluw, J.S. Kalpoe, A. Wagemakers, A. Vahidnia, F.N. Lauw, D.W.M. Verhagen, M. van Wijk, W.F.W. Bierman, M. Bakker, R.A. van Bentum, M.A. van den Boomgaard, J. Kleinnijenhuis, E. Kloeze, A. Middel, D.F. Postma, H.M. Schenk, Y. Stienstra, M. Wouthuyzen-Bakker, A. Boonstra, H. de Jonge, M.M.M. Maerman, D.A. de Weerd, K.J. van Eije, M. Knoester, C.C. van Leer-Buter, H.G.M. Niesters, null T.Mudrikova, R.E. Barth, A.H.W. Bruns, P.M. Ellerbroek, M.P.M. Hensgens, J.J. Oosterheert, E.M. Schadd, A. Verbon, B.J. van Welzen, H. Berends, B.M.G. Griffioen-van Santen, I. de Kroon, F.M. Verduyn Lunel, A.M.J. Wensing, S. Zaheri, A.C. Boyd, D.O. Bezemer, A.I. van Sighem, C. Smit, M.M.J. Hillebregt, T.J. Woudstra, T. Rutkens, D. Bergsma, N.M. Brétin, K.J. Lelivelt, L. van de Sande, K.M. Visser.S.T. van der Vliet, F. Paling, L.G.M. de Groot-Berndsen, M. van den Akker, R. Alexander, Y. Bakker, A. El Berkaoui, M. Bezemer-Goedhart, E.A. Djoechro, M. Groters, L.E. Koster, C.R.E. Lodewijk, E.G.A. Lucas, L. Munjishvili, B.M. Peeck, C.M.J. Ree, R. Regtop, A.F. van Rijk, Y.M.C. Ruijs-Tiggelman, P.P. Schnörr, M.J.C. Schoorl, E.M. Tuijn, D.P. Veenenberg, E.C.M. Witte, I. Karpov, M. Losso, J. Lundgren, J. Rockstroh, I. Aho, L.D. Rasmussen, P. Novak, C. Pradier, N. Chkhartishvili, R. Matulionyte, C. Oprea, J.D. Kowalska, J. Begovac, J.M. Miró, G. Guaraldi, R. Paredes, L. Peters, J.F. Larsen, B. Neesgaard, N. Jaschinski, O. Fursa, D. Raben, D. Kristensen, A.H. Fischer, S.K. Jensen, T.W. Elsing, M. Gardizi, A. Mocroft, A. Phillips, J. Reekie, A. Cozzi-Lepri, A. Pelchen-Matthews, A. Roen, E.S. Tusch, W. Bannister, P. Bellecave, P. Blanco, F. Bonnet, S. Bouchet, D. Breilh, C. Cazanave, S. Desjardin, V. Gaborieau, A. Gimbert, M. Hessamfar, L. Lacaze-Buzy, D. Lacoste, M.E. Lafon, E. Lazaro, O. Leleux, F. Le Marec, G. Le Moal, D. Malvy, L. Marchand, P. Mercié, D. Neau, I. Pellegrin, A. Perrier, V. Petrov-Sanchez, M.O. Vareil, L. Wittkop, N. Bernard, D. Bronnimann H. Chaussade, D. Dondia, P. Duffau, I. Faure, P. Morlat, E. Mériglier, F. Paccalin, E. Riebero, C. Rivoisy, M.A. Vandenhende, L. Barthod, F.A. Dauchy, A. Desclaux, M. Ducours, H. Dutronc, A. Duvignaud, J. Leitao, M. Lescure, D. Nguyen, T. Pistone, M. Puges, G. Wirth, C. Courtault, F. Camou, C. Greib, J.L. Pellegrin, E. Rivière, J.F. Viallard, Y. Imbert, M. Thierry-Mieg, P. Rispal, O. Caubet, H. Ferrand, S. Tchamgoué, S. Farbos, H. Wille, K. Andre, L. Caunegre, Y. Gerard, F. Osorio-Perez, I. Chossat, G. Iles, M. Labasse-Depis, F. Lacassin, A. Barret, B. Castan, J. Koffi, N. Rouanes, A. Saunier, J.B. Zabbe, G. Dumondin, G. Beraud, M. Catroux, M. Garcia, V. Giraud, J.P. Martellosio, F. Roblot, T. Pasdeloup, A. Riché, M. Grosset, S. Males, C. Ngo Bell, C. Carpentier, Virology P. Bellecave, C. Tumiotto, G. Miremeont-Salamé, D. Arma, G. Arnou, M.J. Blaizeau, P. Camps, M. Decoin, S. Delveaux, F. Diarra, L. Gabrea, S. Lawson-Ayayi, E. Lenaud, D. Plainchamps, A. Pougetoux, B. Uwamaliya, K. Zara, V. Conte, M. Gapillout, Internal medicine, VU University medical center, Medical Microbiology and Infection Prevention, AII - Infectious diseases, CCA - Cancer biology and immunology, AII - Inflammatory diseases, AMS - Rehabilitation & Development, APH - Quality of Care, Pulmonary medicine, ACS - Pulmonary hypertension & thrombosis, Ethics, Law & Medical humanities, APH - Methodology, Midwifery Science, Amsterdam Reproduction & Development (AR&D), Infectious diseases, APH - Digital Health, APH - Personalized Medicine, APH - Aging & Later Life, APH - Global Health, Global Health, APH - Health Behaviors & Chronic Diseases, Center of Experimental and Molecular Medicine, General Internal Medicine, AII - Cancer immunology, Landsteiner Laboratory, Cardiology, ACS - Heart failure & arrhythmias, Obstetrics and Gynaecology, ARD - Amsterdam Reproduction and Development, Microbes in Health and Disease (MHD), Bordeaux population health (BPH), Université de Bordeaux (UB)-Institut de Santé Publique, d'Épidémiologie et de Développement (ISPED)-Institut National de la Santé et de la Recherche Médicale (INSERM), Global Health in the Global South (GHiGS), Institut de Recherche pour le Développement (IRD)- Bordeaux population health (BPH), and Université de Bordeaux (UB)-Institut de Santé Publique, d'Épidémiologie et de Développement (ISPED)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Bordeaux (UB)-Institut de Santé Publique, d'Épidémiologie et de Développement (ISPED)-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
Hepatitis B virus, model validation, Hepatology, liver neoplasms, risk prediction models, liver cirrhosis, lnfectious Diseases and Global Health Radboud Institute for Molecular Life Sciences [Radboudumc 4], risk assessment, 610 Medicine & health, hepatocellular carcinoma, HIV infection, tenofovir, lnfectious Diseases and Global Health Radboud Institute for Health Sciences [Radboudumc 4], [SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie, 610 Medizin und Gesundheit
Abstract

Background & Aims: HBV coinfection is common among people living with HIV (PLWH) and is the most important cause of hepatocellular carcinoma (HCC). While risk prediction tools for HCC have been validated in patients with HBV monoinfection, they have not been evaluated in PLWH. Thus, we performed an external validation of PAGE-B in people with HIV/HBV coinfection.Methods: We included data on PLWH from four European cohorts who were positive for HBsAg and did not have HCC before starting tenofovir. We estimated the predictive performance of PAGE-B for HCC occurrence over 15 years in patients receiving tenofovir-containing antiretroviral therapy. Model discrimination was assessed after multiple imputation using Cox regression with the prognostic index as a covariate, and by calculating Harrell's c-index. Calibration was assessed by comparing our cumulative incidence with the PAGE-B derivation study using Kaplan-Meier curves.Results: In total, 2,963 individuals with HIV/HBV coinfection on tenofovir-containing antiretroviral therapy were included. PAGE-B was Conclusions: For individuals with HIV/HBV coinfection, PAGE-B is a valid tool to determine the need for HCC screening. Impact and implications: Chronic HBV infection is the most important cause of hepatocellular carcinoma (HCC) among people living with HIV. Valid risk prediction may enable better targeting of HCC screening efforts to high-risk individuals. We aimed to validate PAGE-B, a risk prediction tool that is based on age, sex, and platelets, in 2,963 individuals with HIV/HBV coinfection who received tenofovir-containing antiretroviral therapy. In the present study, PAGE-B showed good discrimination, adequate calibration, and a cut-off of

Published
2023
Full Text
View/download PDF

86. Anomalous strain relaxation and its impact on the valence-driven spin-state/metal-insulator transition in epitaxial (Pr1−yYy)1−xCaxCoO3−δ

Author

Dewey, John E., primary, Ghosh, Supriya, additional, Chaturvedi, Vipul, additional, Postiglione, William M., additional, Figari, Lucca, additional, Jacobson, Andrew, additional, Korostynski, Caroline, additional, Charlton, Timothy R., additional, Mkhoyan, K. Andre, additional, and Leighton, Chris, additional

Published
2023
Full Text
View/download PDF

92. Giant Dampinglike-Torque Efficiency in Naturally Oxidized Polycrystalline TaAs Thin Films

Author

Wilson Yanez, Yongxi Ou, Run Xiao, Supriya Ghosh, Jyotirmay Dwivedi, Emma Steinebronn, Anthony Richardella, K. Andre Mkhoyan, and Nitin Samarth

Subjects
Condensed Matter - Materials Science, Condensed Matter::Materials Science, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Physics and Astronomy, Condensed Matter::Strongly Correlated Electrons
Abstract

We report the measurement of efficient charge-to-spin conversion at room temperature in Weyl semimetal/ferromagnet heterostructures with both oxidized and pristine interfaces. Polycrystalline films of the Weyl semimetal, TaAs, are grown by molecular beam epitaxy on (001) GaAs and interfaced with a metallic ferromagnet (Ni$_{0.8}$Fe$_{0.2}$). Spin torque ferromagnetic resonance (ST-FMR) measurements in samples with an oxidized interface yield a spin torque efficiency as large as $\xi_{\mathrm{FMR}}=0.45\pm 0.25$ for a 8 nm Ni$_{0.8}$Fe$_{0.2}$ layer thickness. By studying ST-FMR in these samples with varying Ni$_{0.8}$Fe$_{0.2}$ layer thickness, we extract a damping-like torque efficiency as high as $\xi_{\mathrm{DL}}=1.36\pm 0.66$. In samples with a pristine (unoxidized) interface, the spin torque efficiency has opposite sign to that observed in oxidized samples ($\xi_{\mathrm{FMR}}=-0.27\pm 0.14$ for a 5 nm Ni$_{0.8}$Fe$_{0.2}$ layer thickness). We also find a lower bound on the spin Hall conductivity ($424 \pm 110 \frac{\hbar}{e}$ S/cm) which is surprisingly consistent with theoretical predictions for the single crystal Weyl semimetal state of TaAs.

Published
2022
Full Text
View/download PDF

94. Platinum Graphene Catalytic Condenser for Millisecond Programmable Metal Surfaces

Author

Onn, Tzia Ming, primary, Gathmann, Sallye R., additional, Guo, Silu, additional, Solanki, Surya Pratap S., additional, Walton, Amber, additional, Page, Benjamin J., additional, Rojas, Geoffrey, additional, Neurock, Matthew, additional, Grabow, Lars C., additional, Mkhoyan, K. Andre, additional, Abdelrahman, Omar A., additional, Frisbie, C. Daniel, additional, and Dauenhauer, Paul J., additional

Published
2022
Full Text
View/download PDF

97. High-Capacity Regenerable H2S Sorbent for Reducing Sulfur Emissions

Author

Satyadileep Dara, Adel Saif El Nasr, Frank Geuzebroek, Saleh Al Hashimi, Andreas Stein, K. Andre Mkhoyan, Yasser Al Wahedi, Xinyu Li, Michael Tsapatsis, Nitish Mittal, Prodromos Daoutidis, Wenyang Zhao, Balasubramanian V. Vaithilingam, Ibrahim Khan, and Supriya Ghosh

Subjects
Sorbent, Materials science, chemistry, Waste management, General Chemical Engineering, chemistry.chemical_element, High capacity, General Chemistry, Sulfur, Industrial and Manufacturing Engineering
Published
2021
Full Text
View/download PDF

98. Few‐Unit‐Cell MFI Zeolite Synthesized using a Simple Di‐quaternary Ammonium Structure‐Directing Agent

Author

Milinda Abeykoon, Xuekui Duan, Tian-Yi Luo, Matheus Dorneles de Mello, Huda Sharbini Kamaluddin, Michael Tsapatsis, Jeffrey D. Rimer, Liang Qi, Alexis T. Bell, J. Anibal Boscoboinik, Supriya Ghosh, Gaurav Kumar, Heng Dai, Katabathini Narasimharao, Peng Lu, Paul J. Dauenhauer, K. Andre Mkhoyan, Shaeel A. Al-Thabaiti, Zaheer Ahmed Khan, and Xinyu Li

Subjects
Chemistry, Organic Chemistry, General Medicine, General Chemistry, ultrasmall crystalline domain, Catalysis, chemistry.chemical_compound, di-quaternary structure directing agents, Adsorption, adsorption, Zeolites | Very Important Paper, Chemical Sciences, pentasil, Polymer chemistry, Ammonium, Particle size, Zeolite, Isomerization, Research Articles, Research Article
Abstract

Synthesis of a pentasil‐type zeolite with ultra‐small few‐unit‐cell crystalline domains, which we call FDP (few‐unit‐cell crystalline domain pentasil), is reported. FDP is made using bis‐1,5(tributyl ammonium) pentamethylene cations as structure directing agent (SDA). This di‐quaternary ammonium SDA combines butyl ammonium, in place of the one commonly used for MFI synthesis, propyl ammonium, and a five‐carbon nitrogen‐connecting chain, in place of the six‐carbon connecting chain SDAs that are known to fit well within the MFI pores. X‐ray diffraction analysis and electron microscopy imaging of FDP indicate ca. 10 nm crystalline domains organized in hierarchical micro‐/meso‐porous aggregates exhibiting mesoscopic order with an aggregate particle size up to ca. 5 μm. Al and Sn can be incorporated into the FDP zeolite framework to produce active and selective methanol‐to‐hydrocarbon and glucose isomerization catalysts, respectively., A simple di‐quaternary ammonium cation was used as structure‐directing agent to prepare few‐unit‐cell (ca. 10 nm) MFI type zeolite catalysts and adsorbents with a wide range of composition (pure silica, aluminosilicate and stannosilicate). The SDA design was selected based on simple heuristic arguments regarding contributions of its structural elements to early crystal growth characteristics of MFI.

Published
2021
Full Text
View/download PDF

99. Mending cracks atom-by-atom in rutile TiO2 with electron beam radiolysis.

Author

Guo, Silu, Yun, Hwanhui, Nair, Sreejith, Jalan, Bharat, and Mkhoyan, K. Andre

Subjects
ELECTRON energy loss spectroscopy, ELECTRON beams, SCANNING transmission electron microscopy, RADIOLYSIS, RUTILE, ELECTRONIC probes
Abstract

Rich electron-matter interactions fundamentally enable electron probe studies of materials such as scanning transmission electron microscopy (STEM). Inelastic interactions often result in structural modifications of the material, ultimately limiting the quality of electron probe measurements. However, atomistic mechanisms of inelastic-scattering-driven transformations are difficult to characterize. Here, we report direct visualization of radiolysis-driven restructuring of rutile TiO2 under electron beam irradiation. Using annular dark field imaging and electron energy-loss spectroscopy signals, STEM probes revealed the progressive filling of atomically sharp nanometer-wide cracks with striking atomic resolution detail. STEM probes of varying beam energy and precisely controlled electron dose were found to constructively restructure rutile TiO2 according to a quantified radiolytic mechanism. Based on direct experimental observation, a "two-step rolling" model of mobile octahedral building blocks enabling radiolysis-driven atomic migration is introduced. Such controlled electron beam-induced radiolytic restructuring can be used to engineer novel nanostructures atom-by-atom. Radiolysis is known for damaging crystals. Here, using STEM, researchers observed radiolysis-driven bond-breakage, atomic movements, & crystal restructuring in rutile TiO2, and proposed a "2-step rolling" model of building blocks. These results open possibilities for constructive use of radiolysis. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

100. Optical Properties of Electrochemically Gated La1−xSrxCoO3−δ as a Topotactic Phase‐Change Material.

Author

Chakraborty, Rohan D., Postiglione, William M., Ghosh, Supriya, Mkhoyan, K. Andre, Leighton, Chris, and Ferry, Vivian E.

Subjects
PHASE change materials, OPTICAL properties, METAL-insulator transitions, REFLECTANCE spectroscopy, OPTICAL control, TRANSITION metals
Abstract

Materials with tunable infrared refractive index changes have enabled active metasurfaces for novel control of optical circuits, thermal radiation, and more. Ion‐gel‐gated epitaxial films of the perovskite cobaltite La1−xSrxCoO3−δ (LSCO) with 0.00 ≤ x ≤ 0.70 offer a new route to significant, voltage‐tuned, nonvolatile refractive index modulation for infrared active metasurfaces, shown here through Kramers–Kronig‐consistent dispersion models, structural and electronic transport characterization, and electromagnetic simulations before and after electrochemical reduction. As‐grown perovskite films are high‐index insulators for x < 0.18 but lossy metals for x > 0.18, due to a percolation insulator‐metal transition. Positive‐voltage gating of LSCO transistors with x > 0.18 reveals a metal‐insulator transition from the metallic perovskite phase to a high‐index (n > 2.5), low‐loss insulating phase, accompanied by a perovskite to oxygen‐vacancy‐ordered brownmillerite transformation at high x. At x < 0.18, despite nominally insulating character, the LSCO films undergo remarkable refractive index changes to another lower‐index, lower‐loss insulating perovskite state with Δn > 0.6. In simulations of plasmonic metasurfaces, these metal‐insulator and insulator‐insulator transitions support significant, varied mid‐infrared reflectance modulation, thus framing electrochemically gated LSCO as a diverse library of room‐temperature phase‐change materials for applications including dynamic thermal imaging, camouflage, and optical memories. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results