Search Results - (Author, Cooperation:D. Boyd)
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1Latest Papers from Table of Contents or Articles in PressH. X. Liao ; R. Lynch ; T. Zhou ; F. Gao ; S. M. Alam ; S. D. Boyd ; A. Z. Fire ; K. M. Roskin ; C. A. Schramm ; Z. Zhang ; J. Zhu ; L. Shapiro ; J. C. Mullikin ; S. Gnanakaran ; P. Hraber ; K. Wiehe ; G. Kelsoe ; G. Yang ; S. M. Xia ; D. C. Montefiori ; R. Parks ; K. E. Lloyd ; R. M. Scearce ; K. A. Soderberg ; M. Cohen ; G. Kamanga ; M. K. Louder ; L. M. Tran ; Y. Chen ; F. Cai ; S. Chen ; S. Moquin ; X. Du ; M. G. Joyce ; S. Srivatsan ; B. Zhang ; A. Zheng ; G. M. Shaw ; B. H. Hahn ; T. B. Kepler ; B. T. Korber ; P. D. Kwong ; J. R. Mascola ; B. F. Haynes
Nature Publishing Group (NPG)
Published 2013Staff ViewPublication Date: 2013-04-05Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: AIDS Vaccines/immunology ; Africa ; Amino Acid Sequence ; Antibodies, Monoclonal/chemistry/genetics/immunology ; Antibodies, Neutralizing/*chemistry/genetics/*immunology ; Antigens, CD4/chemistry/immunology ; Cell Lineage ; Cells, Cultured ; Clone Cells/cytology ; Cross Reactions/immunology ; Crystallography, X-Ray ; Epitopes/chemistry/immunology ; *Evolution, Molecular ; HIV Antibodies/*chemistry/genetics/*immunology ; HIV Envelope Protein gp120/chemistry/genetics/immunology/metabolism ; HIV-1/*chemistry/classification/*immunology ; Humans ; Models, Molecular ; Molecular Sequence Data ; Mutation ; Neutralization Tests ; Phylogeny ; Protein Structure, TertiaryPublished by: -
2Latest Papers from Table of Contents or Articles in PressT. J. O'Connor ; D. Boyd ; M. S. Dorer ; R. R. Isberg
American Association for the Advancement of Science (AAAS)
Published 2012Staff ViewPublication Date: 2012-12-15Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; Bacterial Proteins/genetics ; Bacterial Secretion Systems/*genetics ; Cells, Cultured ; Drosophila melanogaster/cytology ; Flavoproteins/genetics ; Genetic Testing/*methods ; Host-Pathogen Interactions/*genetics ; Humans ; Legionella pneumophila/*genetics/*growth & development ; Macrophages/microbiology ; Mutagenesis, Insertional/*methods ; RNA Interference ; Sequence Deletion ; Vacuoles/physiologyPublished by: -
3Latest Papers from Table of Contents or Articles in PressA. Valouev ; S. M. Johnson ; S. D. Boyd ; C. L. Smith ; A. Z. Fire ; A. Sidow
Nature Publishing Group (NPG)
Published 2011Staff ViewPublication Date: 2011-05-24Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: CD4-Positive T-Lymphocytes/metabolism ; CD8-Positive T-Lymphocytes/metabolism ; Cells, Cultured ; Chromatin Assembly and Disassembly/*physiology ; *Gene Expression Regulation ; Genome, Human/genetics ; Granulocytes/metabolism ; High-Throughput Nucleotide Sequencing ; Humans ; Micrococcal Nuclease/metabolism ; Nucleosomes/chemistry/genetics/*metabolism ; Organ Specificity ; Transcription, GeneticPublished by: -
4Latest Papers from Table of Contents or Articles in PressS. S. Chng ; M. Xue ; R. A. Garner ; H. Kadokura ; D. Boyd ; J. Beckwith ; D. Kahne
American Association for the Advancement of Science (AAAS)
Published 2012Staff ViewPublication Date: 2012-09-01Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Bacterial Outer Membrane Proteins/chemistry/genetics/*metabolism ; Biological Transport ; Cystine/genetics/*metabolism ; Escherichia coli/genetics/*metabolism ; Escherichia coli Proteins/chemistry/genetics/*metabolism ; Lipopolysaccharides/*metabolism ; Protein Disulfide-Isomerases/metabolism ; Protein Folding ; Protein Structure, SecondaryPublished by: -
5Articles: DFG German National LicensesGuharay, S. K. ; Boyd, D. A. ; Ellis, R. F. ; Stauffer, F. J. ; Lasnier, C. J.
[S.l.] : American Institute of Physics (AIP)
Published 1990Staff ViewISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: A 19-channel grating polychromator is developed to measure the temporal evolution of the electron cyclotron emission spectrum in the second and third harmonics in MTX tokamak with an aim to determine the electron temperature in ohmically heated thermal plasmas as well as the electron energy distribution function in gyrotron and free-electron laser-pumped nonthermal plasmas. The spectrometer can cover a spectral range of about 0.3 to 1.4 mm and deliver a maximum spatial resolution of about 1 cm radially. A combination of a 90° off-axis paraboloidal mirror as the collimating element and a toroidal mirror to focus the diffracted beam yields images on the exit slits with a modest astigmatic distortion. Liquid-helium-cooled InSb detectors are installed in nine channels and associated electronics are optimized for a very low noise and fast response time ( ∼ 2 μs). A faster detector element, with response 〈 100 ns, is envisioned for the remaining ten channels.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesBoyd, D. A. ; Skiff, F. ; Colborn, J. A.
[S.l.] : American Institute of Physics (AIP)
Published 1992Staff ViewISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: The method of cyclotron wave transmission for measuring the electron parallel momentum distribution is studied in a lower-hybrid driven tokamak plasma. Questions of resolution, sensitivity, and technique are addressed. Measurements are made of the suprathermal distribution produced by current drive as well as the incremental changes in the distribution function produced by short pulses of lower-hybrid waves. The results indicate that cyclotron wave transmission is well suited for studies of electron velocity space phenomena and may be used to detect the effect of diagnostic perturbations. This research was supported by the U. S. Department of Energy.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesStaff View
ISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: A two-chord, four-beam suprathermal electron diagnostic has been installed on TdeV (B〉1.5 T, R=0.86 m, a=0.25 m). Resonant absorption of extraordinary mode electron cyclotron waves is measured to deduce the chordal averaged suprathermal electron distribution function amplitude at the resonant momentum. Simultaneously counterpropagating beams permit good refractive loss cancellation. A nonlinear frequency sweep leads to a concentration of appropriately propagating power in a narrow range of time of flight, thus increasing the signal-to-noise ratio and facilitating the rejection of spurious reflections. Numerous measurements of electron distribution functions have been obtained during lower-hybrid current-drive experiments. © 1997 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesStaff View
ISSN: 1365-2494Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, NutritionType of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesStaff View
ISSN: 1365-2494Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, NutritionType of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesStaff View
ISSN: 1365-2494Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, NutritionNotes: The paper describes the use of fertilizers on grassland in England and Wales, as shown by surveys of fertilizer practice carried out during 1957–60.About a third of the total consumption of N and K and almost half the total consumption of P is on grassland. Fertilizer use on leys has increased rapidly in recent years and the overall average rate of application is now of the order of 0·3 cwt N, P2O5 and K2O per acre per annum; permanent grass receives about half as much P and very much less N and K than the leys.Generally speaking, consumption of N and K per acre of grassland was higher in arable districts than in livestock-farming areas, and on dairy farms than on rearing and feeding farms. However, rearing and feeding farms received more P per acre of grass (in particular, more basic slag) than arable farms. Little farmyard manure was used on grassland in the arable districts, whereas in the dairy counties of the western half of England and in Wales it formed a substantial part of the total plant nutrients supplied to grassland, particularly on fields mown for hay.The paper also gives information on types of fertilizers used and the timing of fertilizer applications to grassland. All but about a fifth of the nitrogen used on grassland was applied between February and April.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesGuharay, S. K. ; Boyd, D. A. ; Ellis, R. F. ; Stauffer, F. J. ; Lasnier, C. J.
[S.l.] : American Institute of Physics (AIP)
Published 1990Staff ViewISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: A 19-channel grating polychromator is developed to measure the temporal evolution of the electron cyclotron emission spectrum in the second and third harmonics in the MTX tokamak with an aim to determine the electron temperature in ohmically heated thermal plasmas as well as the electron energy distribution function in gyrotron and free-electron laser-pumped nonthermal plasmas. The spectrometer can cover a spectral range of about 0.3 to 1.4 mm and deliver a maximum spatial resolution of about 1 cm radially. A combination of a 90° off-axis paraboloidal mirror as the collimating element and a toroidal mirror to focus the diffracted beam yields images on the exit slits with a modest astigmatic distortion. Liquid-helium-cooled InSb detectors are installed in nine channels and associated electronics are optimized for a very low noise and fast response time (∼2 μs). A faster detector element, with response 〈100 ns, is envisioned for the remaining ten channels.Type of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesStaff View
ISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: Electron cyclotron emission from a spheromak plasma may be able to provide information about the confining magnetic field. Emission generated in the extraordinary mode with its electric vector perpendicular to the local magnetic field at sufficiently high frequency will propagate out of the plasma while retaining the orientation of the electric vector that it had at its source. Thus a measurement of the orientation of the emergent electric vector and the frequency of the emitted wave will allow one to deduce the orientation and strength of the magnetic field at the radiation source. A simple model of the Maryland spheromak is used to determine the practicality of this diagnostic possibility.Type of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesGuharay, S. K. ; Boyd, D. A. ; Ellis, R. F.
[S.l.] : American Institute of Physics (AIP)
Published 1986Staff ViewISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: This ECE (electron cyclotron emission) diagnostic utilizes a fast-scanning Michelson interferometer to determine two parameters, the temperature and the loss cone angle, of the distribution function of the hot electrons (T(approximately-greater-than)100 keV) generated in the axisymmetric plug plasma of the TARA tandem mirror device. The radiation transport system employs a lens relay and a low-pass grating filter in order to transmit the synchrotron radiation over a spectral range of 2.9–18.6 cm−1. This enables us to study the emitted radiation spectrum up to the 40th harmonic of the electron–cyclotron frequency in the plug plasma (B=5 kG). Details of the design principles and the development of the diagnostic at TARA will be presented.Type of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesStauffer, F. J. ; Boyd, D. A. ; Cutler, R. C. ; Diesso, M. ; McCarthy, M. P. ; Montague, J. ; Rocco, R.
[S.l.] : American Institute of Physics (AIP)
Published 1988Staff ViewISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: For the past four years, a Fourier transform spectrometer diagnostic system, employing a fast-scanning polarizing Michelson interferometer (FMI), has been operating on the TFTR tokamak at the Princeton Plasma Physics Laboratory. It is used to measure the electron cyclotron emission (ECE) spectrum over the range 2.5–18 cm−1 (75–540 GHz), with a resolution of 0.123 cm−1 (3.7 GHz), at a rate of 72 spectra per second. The quasioptical system for collecting the light and transporting it through the interferometer to the detector has been designed using the concepts of both Gaussian and geometrical optics. The commercial FMI was custom made for this project and is the state of the art for this type of specialized instrument. The diagnostic system is described and an error propagation analysis of the absolute calibration process is given. Examples of ECE spectra measured in two polarization directions are given and electron temperature profiles derived from each of them are compared.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesJames, Reed ; Janz, S. ; Ellis, R. ; Boyd, D. ; Lohr, John
[S.l.] : American Institute of Physics (AIP)
Published 1988Staff ViewISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: The vertical-viewing electron cyclotron emission diagnostic on DIII-D will be used to assess the nonthermal electron distributions resulting from electron cyclotron heating and electron cyclotron current drive experiments. Electron cyclotron emission along a vertical chord is collected using an ellipsoidal focusing mirror and retroreflector (the latter to minimize wall reflections). The emission is then transported ∼20 m using a quasioptical transport system composed of eight lenses and three mirrors, and detected between the 2nd and the 10th harmonics by a fast-scanning (40-Hz) Michelson interferometer. The entire system has been aligned using a Gaussian beam simulator and absolutely calibrated in situ using a cold liquid-nitrogen bath. Details of the design, installation, and calibration will be discussed.Type of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesStaff View
ISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: The tokamak fusion test reactor (TFTR) Michelson interferometer, which is used as an electron-temperature diagnostic, has a spectral range of 75–540 GHz. This range is adequate for measuring at least the first three cyclotron harmonics, and it spans both optically thick and thin portions of the electron cyclotron emission (ECE) spectrum. During the most recent opening of the TFTR vacuum vessel, a concave, carbon reflector was installed on the back wall of the vessel, opposite the light-collecting optic of the Michelson system. The reflector is designed to prevent the observation of optically thin ECE that originates from a location that is outside the field of view of the light collecting optic. If this is achieved, it should be possible to derive the electron-density profile from measurements of either the extraordinary mode third harmonic or the ordinary mode second harmonic. An analysis of ECE spectra that have been measured before and after installation of the reflector will be presented. This work was supported by U.S. DOE Contract No. DE-AC02-76-CHO-3073.Type of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesStauffer, F. J. ; Boyd, D. A. ; Cutler, R. C. ; McCarthy, M. P.
[S.l.] : American Institute of Physics (AIP)
Published 1985Staff ViewISSN: 1089-7623Source: AIP Digital ArchiveTopics: PhysicsElectrical Engineering, Measurement and Control TechnologyNotes: In July 1984, a Fourier transform spectrometer employing a fast-scanning Michelson interferometer began operating on TFTR. This diagnostic system can measure the electron cyclotron emission spectrum 72 times per s with a time resolution of 11 ms and a spectral resolution of 3.6 GHz. The initial operating spectral range is 75–540 GHz, which is adequate for measuring the first three cyclotron harmonics at present TFTR magnetic field levels. The range can be extended easily to 75–1080 GHz in order to accommodate increases in toroidal magnetic field or to study superthermal ECE. The measured spectra are absolutely calibrated using a liquid nitrogen cooled blackbody reference source. The second harmonic feature of each spectrum is used to calculate the absolute electron temperature profile.Type of Medium: Electronic ResourceURL: -
18Articles: DFG German National LicensesDestler, W. W. ; Aghamir, F. M. ; Boyd, D. A. ; Bekefi, G. ; Shefer, R. E. ; Yin, Y. Z.
[S.l.] : American Institute of Physics (AIP)
Published 1985Staff ViewISSN: 1089-7666Source: AIP Digital ArchiveTopics: PhysicsNotes: The generation of millimeter wave radiation from the interaction of a rotating electron beam (2 MeV, 1 kA, 5 nsec) with an azimuthally periodic wiggler magnetic field has been studied experimentally. Calculations of the effects of the wiggler magnetic field on the single particle electron orbits are presented, together with experimental measurements of the effects of the wiggler field on the electron beam. Narrow-band radiation at power levels in excess of 200 kW has been observed at 88 and 175 GHz for wiggler fields with 6.28 and 3.14 cm periods, respectively. The radiation frequency spectra for various experimental configurations are presented, and results are compared with theoretical expectations.Type of Medium: Electronic ResourceURL: -
19Articles: DFG German National LicensesColborn, J. A. ; Porkolab, M. ; Squire, J. P. ; Villaseñor, J. ; Skiff, F. ; Boyd, D. A. ; Harvey, R. W.
New York, NY : American Institute of Physics (AIP)
Published 1993Staff ViewISSN: 1089-7666Source: AIP Digital ArchiveTopics: PhysicsNotes: A "two-parallel-temperature'' feature of the fast-electron distribution function has been observed during lower-hybrid current-drive experiments on the Versator-II tokamak (B. Richards, Ph.D. thesis, Massachusetts Institute of Technology, 1981). Computational modeling predicts this feature and indicates that the colder tail is initiated by low-power, high-N(parallel) waves from the sidelobes of the antenna N(parallel) spectrum. The modeling indicates these waves bridge the "spectral gap,'' enabling current drive even though the wave parallel phase velocity greatly exceeds the electron thermal velocity for the majority of the wave power.Type of Medium: Electronic ResourceURL: -
20Articles: DFG German National LicensesKleva, Robert G. ; Drake, J. F. ; Boyd, D. A.
[S.l.] : American Institute of Physics (AIP)
Published 1986Staff ViewISSN: 1089-7666Source: AIP Digital ArchiveTopics: PhysicsNotes: In numerical simulations of q=2 tearing modes, the maximum amplitude of the mode is found to increase rapidly as the safety factor on axis q(0) rises above 1.5. The associated magnetic islands grow to the center of the column, encompassing virtually the entire plasma cross section. As a result of the formation of these very large islands, the hot central plasma is rapidly convected out to the edge of the column, thereby destroying central confinement. Experimental evidence from several tokamaks linking the formation of these very large islands with major disruptions is presented. Typically, major disruptions are observed to occur in two (or more) stages. During the first stage(s) q rises on axis while the final stage, which terminates the discharge, is associated with the violent growth of an m=2 perturbation. Under some circumstances q=2 sawteeth are predicted to occur. Evidence for such sawteeth in a divertor tokamak is discussed.Type of Medium: Electronic ResourceURL: