Institution
University of Copenhagen
Education•Copenhagen, Denmark•
About: University of Copenhagen is a education organization based out in Copenhagen, Denmark. It is known for research contribution in the topics: Population & Galaxy. The organization has 57645 authors who have published 149740 publications receiving 5903093 citations. The organization is also known as: Copenhagen University & Københavns Universitet.
Topics: Population, Galaxy, Insulin, Skeletal muscle, Diabetes mellitus
Papers published on a yearly basis
Papers
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TL;DR: In this paper, a model for the development during the Baltic Ice Lake, Yoldia Sea, and Ancylus Lake stages is presented based on the present-state-of-knowledge and certain hypotheses.
800 citations
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TL;DR: A single-electron transistor where the electronic levels of a single π-conjugated molecule in several distinct charged states control the transport properties is described, leading to a very significant reduction of the gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital.
Abstract: A combination of classical Coulomb charging, electronic level spacings, spin, and vibrational modes determines the single-electron transfer reactions through nanoscale systems connected to external electrodes by tunnelling barriers1. Coulomb charging effects have been shown to dominate such transport in semiconductor quantum dots2, metallic3 and semiconducting4 nanoparticles, carbon nanotubes5,6, and single molecules7,8,9. Recently, transport has been shown to be also influenced by spin—through the Kondo effect—for both nanotubes10 and single molecules8,9, as well as by vibrational fine structure7,11. Here we describe a single-electron transistor where the electronic levels of a single π-conjugated molecule in several distinct charged states control the transport properties. The molecular electronic levels extracted from the single-electron-transistor measurements are strongly perturbed compared to those of the molecule in solution, leading to a very significant reduction of the gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital. We suggest, and verify by simple model calculations, that this surprising effect could be caused by image charges generated in the source and drain electrodes resulting in a strong localization of the charges on the molecule.
799 citations
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TL;DR: It is shown that certain GH61 proteins lack measurable hydrolytic activity but in the presence of various divalent metal ions can significantly reduce the total protein loading required to hydrolyze lignocellulosic biomass, and it is concluded that the GH 61 proteins are unlikely to be glycoside hydrolases.
Abstract: Currently, the relatively high cost of enzymes such as glycoside hydrolases that catalyze cellulose hydrolysis represents a barrier to commercialization of a biorefinery capable of producing renewable transportable fuels such as ethanol from abundant lignocellulosic biomass. Among the many families of glycoside hydrolases that catalyze cellulose and hemicellulose hydrolysis, few are more enigmatic than family 61 (GH61), originally classified based on measurement of very weak endo-1,4-beta-d-glucanase activity in one family member. Here we show that certain GH61 proteins lack measurable hydrolytic activity by themselves but in the presence of various divalent metal ions can significantly reduce the total protein loading required to hydrolyze lignocellulosic biomass. We also solved the structure of one highly active GH61 protein and find that it is devoid of conserved, closely juxtaposed acidic side chains that could serve as general proton donor and nucleophile/base in a canonical hydrolytic reaction, and we conclude that the GH61 proteins are unlikely to be glycoside hydrolases. Structure-based mutagenesis shows the importance of several conserved residues for GH61 function. By incorporating the gene for one GH61 protein into a commercial Trichoderma reesei strain producing high levels of cellulolytic enzymes, we are able to reduce by 2-fold the total protein loading (and hence the cost) required to hydrolyze lignocellulosic biomass.
799 citations
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TL;DR: A test for the phagocytic efficiency of BMMs by exposing them to fluorescently labeled yeast zymosan bioparticles is described and a method to deliver DNA or small interfering RNAs into these hard-to-transfect cells is described.
Abstract: INTRODUCTIONBone marrow-derived macrophages (BMM) are primary macrophage cells, derived from bone marrow cells in vitro in the presence of growth factors. Macrophage colony-stimulating factor (M-CSF) is a lineage-specific growth factor that is responsible for the proliferation and differentiation of committed myeloid progenitors into cells of the macrophage/monocyte lineage. Mice lacking functional M-CSF are deficient in macrophages and osteoclasts and suffer from osteopetrosis. In this protocol, bone marrow cells are grown in culture dishes in the presence of M-CSF, which is secreted by L929 cells and is used in the form of L929-conditioned medium. Under these conditions, the bone marrow monocyte/macrophage progenitors will proliferate and differentiate into a homogenous population of mature BMMs. The efficiency of the differentiation is assessed using fluorescence-activated cell sorting (FACS) analysis of Mac-1 and 4/80 surface antigen expression. Once differentiated, the BMMs are suitable for numerous types of experimental manipulations, including morphological, gene expression, and physiological studies. For example, phagocytic cells such as macrophages have a unique ability to ingest microbes. We describe a test for the phagocytic efficiency of BMMs by exposing them to fluorescently labeled yeast zymosan bioparticles. Also, a method to deliver DNA or small interfering RNAs (siRNAs) into these hard-to-transfect cells is described. Finally, the proliferation of the BMMs is assayed using carboxyfluorescein succinimidyl ester (CFSE), a fluorescein derivative that partitions equally between daughter cells after cell division.
797 citations
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Search for extraterrestrial intelligence1, Harvard University2, University of California, Santa Cruz3, Ames Research Center4, Massachusetts Institute of Technology5, San Diego State University6, Villanova University7, Konkoly Thege Miklós Astronomical Institute8, University of Copenhagen9, University of California, Berkeley10, Las Cumbres Observatory Global Telescope Network11, University of California, Santa Barbara12, San Jose State University13, Smithsonian Astrophysical Observatory14, Fermilab15, Lowell Observatory16, University of Texas at Austin17, Carnegie Institution for Science18, Yale University19
TL;DR: The detection of a planet whose orbit surrounds a pair of low-mass stars, comparable to Saturn in mass and size and on a nearly circular 229-day orbit around its two parent stars, suggests that the planet formed within a circumbinary disk.
Abstract: We report the detection of a planet whose orbit surrounds a pair of low-mass stars. Data from the Kepler spacecraft reveal transits of the planet across both stars, in addition to the mutual eclipses of the stars, giving precise constraints on the absolute dimensions of all three bodies. The planet is comparable to Saturn in mass and size and is on a nearly circular 229-day orbit around its two parent stars. The eclipsing stars are 20 and 69% as massive as the Sun and have an eccentric 41-day orbit. The motions of all three bodies are confined to within 0.5° of a single plane, suggesting that the planet formed within a circumbinary disk.
797 citations
Authors
Showing all 58387 results
Name | H-index | Papers | Citations |
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Michael Karin | 236 | 704 | 226485 |
Matthias Mann | 221 | 887 | 230213 |
Peer Bork | 206 | 697 | 245427 |
Ronald Klein | 194 | 1305 | 149140 |
Kenneth S. Kendler | 177 | 1327 | 142251 |
Dorret I. Boomsma | 176 | 1507 | 136353 |
Ramachandran S. Vasan | 172 | 1100 | 138108 |
Unnur Thorsteinsdottir | 167 | 444 | 121009 |
Mika Kivimäki | 166 | 1515 | 141468 |
Jun Wang | 166 | 1093 | 141621 |
Anders Björklund | 165 | 769 | 84268 |
Gerald I. Shulman | 164 | 579 | 109520 |
Jaakko Kaprio | 163 | 1532 | 126320 |
Veikko Salomaa | 162 | 843 | 135046 |
Daniel J. Jacob | 162 | 656 | 76530 |