Author
Lothar Helm
Other affiliations: International Pentecostal Holiness Church, École Polytechnique, University of Lausanne ...read more
Bio: Lothar Helm is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Lanthanide & Aqueous solution. The author has an hindex of 59, co-authored 230 publications receiving 12390 citations. Previous affiliations of Lothar Helm include International Pentecostal Holiness Church & École Polytechnique.
Papers published on a yearly basis
Papers
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TL;DR: In this article, the magnetism in graphene induced by single carbon atom defects has been studied from first principles and the itinerant magnetism due to the defect-induced extended states has been observed.
Abstract: We study from first principles the magnetism in graphene induced by single carbon atom defects For two types of defects considered in our study, the hydrogen chemisorption defect and the vacancy defect, the itinerant magnetism due to the defect-induced extended states has been observed Calculated magnetic moments are equal to 1µB per hydrogen chemisorption defect and 112–153µB per vacancy defect depending on the defect concentration The coupling between the magnetic moments is either ferromagnetic or antiferromagnetic, depending on whether the defects correspond to the same or to different hexagonal sublattices of the graphene lattice, respectively The relevance of itinerant magnetism in graphene to the high-TC magnetic ordering is discussed
1,257 citations
TL;DR: In this paper, the magnetism in graphene induced by single carbon atom defects was studied from first principles and the relevance of itinerant magnetism to the high-$T_C$ magnetic ordering was discussed.
Abstract: We study from first principles the magnetism in graphene induced by single carbon atom defects. For two types of defects considered in our study, the hydrogen chemisorption defect and the vacancy defect, the itinerant magnetism due to the defect-induced extended states has been observed. Calculated magnetic moments are equal to 1 $\mu_B$ per hydrogen chemisorption defect and 1.12$-$1.53 $\mu_B$ per vacancy defect depending on the defect concentration. The coupling between the magnetic moments is either ferromagnetic or antiferromagnetic, depending on whether the defects correspond to the same or to different hexagonal sublattices of the graphene lattice, respectively. The relevance of itinerant magnetism in graphene to the high-$T_C$ magnetic ordering is discussed.
996 citations
TL;DR: This poster presents a probabilistic simulation of the response of the immune system to EMMARM, which shows clear patterns of protection against infection and infection-like symptoms.
Abstract: Reference LCIB-ARTICLE-2007-010doi:10.1021/cr030726oView record in Web of Science Record created on 2007-02-14, modified on 2017-05-12
633 citations
TL;DR: In this article, the authors demonstrate the complementary of experimental studies and computer simulations or quantum chemical calculations performed on the water exchange reaction between coordination shells around metal ions in aqueous solution.
445 citations
TL;DR: Nanoscale confinement offers a new and general strategy for enhancing the contrast of gadolinium-based contrast agents by confining contrast agents inside the nanoporous structure of silicon particles.
Abstract: Confining gadolinium-based contrast agents inside the porous structure of silicon microparticles can improve their T1 contrast, offering a general approach for developing highly efficient MRI contrast agents.
375 citations
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TL;DR: A. Relaxivity 2331 E. Outerand Second-Sphere relaxivity 2334 F. Methods of Improving Relaxivity 2336 V. Macromolecular Conjugates 2336.
Abstract: A. Water Exchange 2326 B. Proton Exchange 2327 C. Electronic Relaxation 2327 D. Relaxivity 2331 E. Outerand Second-Sphere Relaxivity 2334 F. Methods of Improving Relaxivity 2336 V. Macromolecular Conjugates 2336 A. Introduction 2336 B. General Conjugation Methods 2336 C. Synthetic Linear Polymers 2336 D. Synthetic Dendrimer-Based Agents 2338 E. Naturally Occurring Polymers (Proteins, Polysaccharides, and Nucleic Acids) 2339
4,125 citations
TL;DR: In this article, the present knowledge about point and line defects in graphene are reviewed and particular emphasis is put on the unique ability of graphene to reconstruct its lattice around intrinsic defects, leading to interesting effects and potential applications.
Abstract: Graphene is one of the most promising materials in nanotechnology. The electronic and mechanical properties of graphene samples with high perfection of the atomic lattice are outstanding, but structural defects, which may appear during growth or processing, deteriorate the performance of graphene-based devices. However, deviations from perfection can be useful in some applications, as they make it possible to tailor the local properties of graphene and to achieve new functionalities. In this article, the present knowledge about point and line defects in graphene are reviewed. Particular emphasis is put on the unique ability of graphene to reconstruct its lattice around intrinsic defects, leading to interesting effects and potential applications. Extrinsic defects such as foreign atoms which are of equally high importance for designing graphene-based devices with dedicated properties are also discussed.
2,828 citations
University of Cambridge1, Istituto Italiano di Tecnologia2, Lancaster University3, University of Manchester4, Catalan Institution for Research and Advanced Studies5, Technical University of Denmark6, Nokia7, Queen Mary University of London8, fondazione bruno kessler9, University of Trento10, Technische Universität München11, Polytechnic University of Milan12, Centre national de la recherche scientifique13, University of Trieste14, University of Ioannina15, University of Geneva16, Trinity College, Dublin17, Texas Instruments18, University of Paris19, Spanish National Research Council20, Leiden University21, Delft University of Technology22, University of Patras23, École Normale Supérieure24, Radboud University Nijmegen25, Nest Labs26, Airbus UK27, Seoul National University28, Yonsei University29, University of Oxford30, Chalmers University of Technology31, University of Groningen32, STMicroelectronics33, Chemnitz University of Technology34, Max Planck Society35, Aalto University36
TL;DR: An overview of the key aspects of graphene and related materials, ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries are provided.
Abstract: We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.
2,560 citations
2,430 citations
TL;DR: This data indicates that the prostate-Specific antigen in the europium-Tetracycline complex acts as a ‘spatially aggregating force’ to form terbium complexes in the Optical Probes.
Abstract: Keywords: Time-Resolved Fluorescence ; Resonance Energy-Transfer ; Near-Infrared Luminescence ; Double-Stranded Dna ; Prostate-Specific Antigen ; Photoinduced Electron-Transfer ; Europium-Tetracycline Complex ; Sybr-Green-I ; Terbium Complexes ; Optical Probes Reference EPFL-ARTICLE-149396doi:10.1021/cr900362eView record in Web of Science Record created on 2010-06-17, modified on 2017-05-12
2,223 citations