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  • 1
    ISSN: 1434-0879
    Keywords: Natural cytotoxicity ; Bladder cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human peripheral blood mononuclear cells obtained by ficoll-hypaque sedimentation were depleted of Fc-receptor-bearing (FcR+) cells. Cytotoxicity (direct killing of target cells by effector cells), tested in a 40 h assay, was significantly decreased against a variety of target cells. Tests in which no FcR+ cells could be detected were also positive for “natural killing” (NK) against a spectrum of target cells from normal donors. NK in this system was mediated by more than one subpopulation of lymphocytes. Monocytes probably did not play a significant role. Decreasing the FcR+ cells in peripheral blood mononuclear cells in patients with bladder cancer and in controls did not reveal specific antitumour activity.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The de Haas-van Alphen effect has been measured in the ordered alloy β′-AgZn by the modulation method, improving and extending the results of earlier observations. The results are in good agreement with recent theoretical calculations of the Fermi surface, although some of the predicted orbits have not been observed. The hole octahedron in the first band and the triangular hole in the second band have been identified unambiguously, and the shape of the octahedron has been determined by inversion.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 26 (1977), S. 291-298 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The de Haas-van Alphen effect has been observed in the quadrivalent β-brass compound MgHg. Five frequency groups have been measured in the {110} and {100} planes along with some effective masses at high symmetry points. All five groups observed are well explained by Skriver's relativistic LMTO band calculation. A football-shaped piece predicted in the third band has the size and shape of an observed closed section which was inverted with tetragonal harmonics. The remaining orbits arise from the multipliconnected second band surface, a surface formed by connecting pockets at Γ andR with arms along 〈111〉.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 19 (1975), S. 51-57 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The de Haas-van Alphen effect has been measured in the layer compound PdTe 2 . Frequency branches from 0.1 kT to 4.5 kT were observed in the three principal planes. Effective masses were also measured. The number of branches suggests a complicated Fermi surface which is not well explained by existing band structures.
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Solid State Communications 8 (1970), S. 1107-1110 
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 6
    Publication Date: 2014-11-14
    Description: Topology, with its abstract mathematical constructs, often manifests itself in physics and has a pivotal role in our understanding of natural phenomena. Notably, the discovery of topological phases in condensed-matter systems has changed the modern conception of phases of matter. The global nature of topological ordering, however, makes direct experimental probing an outstanding challenge. Present experimental tools are mainly indirect and, as a result, are inadequate for studying the topology of physical systems at a fundamental level. Here we employ the exquisite control afforded by state-of-the-art superconducting quantum circuits to investigate topological properties of various quantum systems. The essence of our approach is to infer geometric curvature by measuring the deflection of quantum trajectories in the curved space of the Hamiltonian. Topological properties are then revealed by integrating the curvature over closed surfaces, a quantum analogue of the Gauss-Bonnet theorem. We benchmark our technique by investigating basic topological concepts of the historically important Haldane model after mapping the momentum space of this condensed-matter model to the parameter space of a single-qubit Hamiltonian. In addition to constructing the topological phase diagram, we are able to visualize the microscopic spin texture of the associated states and their evolution across a topological phase transition. Going beyond non-interacting systems, we demonstrate the power of our method by studying topology in an interacting quantum system. This required a new qubit architecture that allows for simultaneous control over every term in a two-qubit Hamiltonian. By exploring the parameter space of this Hamiltonian, we discover the emergence of an interaction-induced topological phase. Our work establishes a powerful, generalizable experimental platform to study topological phenomena in quantum systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Roushan, P -- Neill, C -- Chen, Yu -- Kolodrubetz, M -- Quintana, C -- Leung, N -- Fang, M -- Barends, R -- Campbell, B -- Chen, Z -- Chiaro, B -- Dunsworth, A -- Jeffrey, E -- Kelly, J -- Megrant, A -- Mutus, J -- O'Malley, P J J -- Sank, D -- Vainsencher, A -- Wenner, J -- White, T -- Polkovnikov, A -- Cleland, A N -- Martinis, J M -- England -- Nature. 2014 Nov 13;515(7526):241-4. doi: 10.1038/nature13891.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of California, Santa Barbara, California 93106-9530, USA. ; Department of Physics, Boston University, Boston, Massachusetts 02215, USA. ; 1] Department of Physics, University of California, Santa Barbara, California 93106-9530, USA [2] Google Inc., Santa Barbara, California 93117, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25391961" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 7
    Publication Date: 2018-04-13
    Description: A key step toward demonstrating a quantum system that can address difficult problems in physics and chemistry will be performing a computation beyond the capabilities of any classical computer, thus achieving so-called quantum supremacy. In this study, we used nine superconducting qubits to demonstrate a promising path toward quantum supremacy. By individually tuning the qubit parameters, we were able to generate thousands of distinct Hamiltonian evolutions and probe the output probabilities. The measured probabilities obey a universal distribution, consistent with uniformly sampling the full Hilbert space. As the number of qubits increases, the system continues to explore the exponentially growing number of states. Extending these results to a system of 50 qubits has the potential to address scientific questions that are beyond the capabilities of any classical computer.
    Keywords: Physics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
    Publication Date: 2014-04-25
    Description: A quantum computer can solve hard problems, such as prime factoring, database searching and quantum simulation, at the cost of needing to protect fragile quantum states from error. Quantum error correction provides this protection by distributing a logical state among many physical quantum bits (qubits) by means of quantum entanglement. Superconductivity is a useful phenomenon in this regard, because it allows the construction of large quantum circuits and is compatible with microfabrication. For superconducting qubits, the surface code approach to quantum computing is a natural choice for error correction, because it uses only nearest-neighbour coupling and rapidly cycled entangling gates. The gate fidelity requirements are modest: the per-step fidelity threshold is only about 99 per cent. Here we demonstrate a universal set of logic gates in a superconducting multi-qubit processor, achieving an average single-qubit gate fidelity of 99.92 per cent and a two-qubit gate fidelity of up to 99.4 per cent. This places Josephson quantum computing at the fault-tolerance threshold for surface code error correction. Our quantum processor is a first step towards the surface code, using five qubits arranged in a linear array with nearest-neighbour coupling. As a further demonstration, we construct a five-qubit Greenberger-Horne-Zeilinger state using the complete circuit and full set of gates. The results demonstrate that Josephson quantum computing is a high-fidelity technology, with a clear path to scaling up to large-scale, fault-tolerant quantum circuits.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Barends, R -- Kelly, J -- Megrant, A -- Veitia, A -- Sank, D -- Jeffrey, E -- White, T C -- Mutus, J -- Fowler, A G -- Campbell, B -- Chen, Y -- Chen, Z -- Chiaro, B -- Dunsworth, A -- Neill, C -- O'Malley, P -- Roushan, P -- Vainsencher, A -- Wenner, J -- Korotkov, A N -- Cleland, A N -- Martinis, John M -- England -- Nature. 2014 Apr 24;508(7497):500-3. doi: 10.1038/nature13171.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Physics, University of California, Santa Barbara, California 93106, USA [2]. ; Department of Physics, University of California, Santa Barbara, California 93106, USA. ; Department of Electrical Engineering, University of California, Riverside, California 92521, USA. ; 1] Department of Physics, University of California, Santa Barbara, California 93106, USA [2] Centre for Quantum Computation and Communication Technology, School of Physics, The University of Melbourne, Victoria 3010, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24759412" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 9
    Publication Date: 2015-03-06
    Description: Quantum computing becomes viable when a quantum state can be protected from environment-induced error. If quantum bits (qubits) are sufficiently reliable, errors are sparse and quantum error correction (QEC) is capable of identifying and correcting them. Adding more qubits improves the preservation of states by guaranteeing that increasingly larger clusters of errors will not cause logical failure-a key requirement for large-scale systems. Using QEC to extend the qubit lifetime remains one of the outstanding experimental challenges in quantum computing. Here we report the protection of classical states from environmental bit-flip errors and demonstrate the suppression of these errors with increasing system size. We use a linear array of nine qubits, which is a natural step towards the two-dimensional surface code QEC scheme, and track errors as they occur by repeatedly performing projective quantum non-demolition parity measurements. Relative to a single physical qubit, we reduce the failure rate in retrieving an input state by a factor of 2.7 when using five of our nine qubits and by a factor of 8.5 when using all nine qubits after eight cycles. Additionally, we tomographically verify preservation of the non-classical Greenberger-Horne-Zeilinger state. The successful suppression of environment-induced errors will motivate further research into the many challenges associated with building a large-scale superconducting quantum computer.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kelly, J -- Barends, R -- Fowler, A G -- Megrant, A -- Jeffrey, E -- White, T C -- Sank, D -- Mutus, J Y -- Campbell, B -- Chen, Yu -- Chen, Z -- Chiaro, B -- Dunsworth, A -- Hoi, I-C -- Neill, C -- O'Malley, P J J -- Quintana, C -- Roushan, P -- Vainsencher, A -- Wenner, J -- Cleland, A N -- Martinis, John M -- England -- Nature. 2015 Mar 5;519(7541):66-9. doi: 10.1038/nature14270.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of California, Santa Barbara, California 93106, USA. ; 1] Department of Physics, University of California, Santa Barbara, California 93106, USA [2] Centre for Quantum Computation and Communication Technology, School of Physics, The University of Melbourne, Victoria 3010, Australia. ; 1] Department of Physics, University of California, Santa Barbara, California 93106, USA [2] Department of Materials, University of California, Santa Barbara, California 93106, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25739628" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 10
    Publication Date: 2016-05-05
    Description: Humans are distinguished from the other living apes in having larger brains and an unusual life history that combines high reproductive output with slow childhood growth and exceptional longevity. This suite of derived traits suggests major changes in energy expenditure and allocation in the human lineage, but direct measures of human and ape metabolism are needed to compare evolved energy strategies among hominoids. Here we used doubly labelled water measurements of total energy expenditure (TEE; kcal day(-1)) in humans, chimpanzees, bonobos, gorillas and orangutans to test the hypothesis that the human lineage has experienced an acceleration in metabolic rate, providing energy for larger brains and faster reproduction without sacrificing maintenance and longevity. In multivariate regressions including body size and physical activity, human TEE exceeded that of chimpanzees and bonobos, gorillas and orangutans by approximately 400, 635 and 820 kcal day(-1), respectively, readily accommodating the cost of humans' greater brain size and reproductive output. Much of the increase in TEE is attributable to humans' greater basal metabolic rate (kcal day(-1)), indicating increased organ metabolic activity. Humans also had the greatest body fat percentage. An increased metabolic rate, along with changes in energy allocation, was crucial in the evolution of human brain size and life history.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pontzer, Herman -- Brown, Mary H -- Raichlen, David A -- Dunsworth, Holly -- Hare, Brian -- Walker, Kara -- Luke, Amy -- Dugas, Lara R -- Durazo-Arvizu, Ramon -- Schoeller, Dale -- Plange-Rhule, Jacob -- Bovet, Pascal -- Forrester, Terrence E -- Lambert, Estelle V -- Thompson, Melissa Emery -- Shumaker, Robert W -- Ross, Stephen R -- R01 DK080763/DK/NIDDK NIH HHS/ -- R01DK080763/DK/NIDDK NIH HHS/ -- England -- Nature. 2016 May 4;533(7603):390-2. doi: 10.1038/nature17654.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Anthropology, Hunter College. 695 Park Avenue, New York, New York 10065, USA. ; New York Consortium for Evolutionary Primatology, New York, New York 10065, USA. ; Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo. Chicago, Illinois 60614, USA. ; School of Anthropology, University of Arizona, 1099 E South Campus Drive, Tucson, Arizona 85716, USA. ; Department of Sociology &Anthropology, University of Rhode Island, 45 Upper College Rd, Kingston, Rhode Island 02881, USA. ; Department of Evolutionary Anthropology, Duke University, Durham, North Carolina 27708, USA. ; Public Health Sciences, Stritch School of Medicine, Loyola University Chicago, 2160 South First Avenue, Maywood, Illinois 60153, USA. ; Nutritional Sciences, Biotechnology Center, University of Wisconsin-Madison, 425 Henry Mall, Madison, Wisconsin 53705, USA. ; Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. ; Institute of Social &Preventive Medicine, Lausanne University Hospital, Rue de la Corniche 10, 1010 Lausanne, Switzerland. ; Ministry of Health, PO Box 52, Victoria, Mahe, Seychelles. ; UWI Solutions for Developing Countries, The University of the West Indies, 25 West Road, UWI Mona Campus, Kingston 7, Jamaica. ; Research Unit for Exercise Science and Sports Medicine, University of Cape Town, PO Box 115, Newlands 7725, Cape Town, South Africa. ; Department of Anthropology, University of New Mexico. Albuquerque, New Mexico 87131, USA. ; Indianapolis Zoo, 1200 W Washington Street, Indianapolis, Indiana 46222, USA. ; Department of Anthropology and Center for Integrated Study of Animal Behavior, Indiana University, 701 E Kirkwood Avenue, Bloomington, Indiana 47405, USA. ; Krasnow Institute for Advanced Study, George Mason University, 4400 University Dr., Fairfax, Virginia 22030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27144364" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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