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Plasma zinc's alter ego is a low-molecular-weight humoral factor
Ou, Ou,Allen-Redpath, Keith,Urgast, Dagmar,Gordon, Margaret-Jane,Campbell, Gill,Feldmann, Jö,rg,Nixon, Graeme F.,Mayer, Claus-Dieter,Kwun, In-Sook,Beattie, John H. The Federation of American Societies for Experimen 2013 The FASEB Journal Vol.27 No.9
<P>Mild dietary zinc deprivation in humans and rodents has little effect on blood plasma zinc levels, and yet cellular consequences of zinc depletion can be detected in vascular and other tissues. We proposed that a zinc-regulated humoral factor might mediate the effects of zinc deprivation. Using a novel approach, primary rat vascular smooth muscle cells (VSMCs) were treated with plasma from zinc-deficient (<1 mg Zn/kg) or zinc-adequate (35 mg Zn/kg, pair-fed) adult male rats, and zinc levels were manipulated to distinguish direct and indirect effects of plasma zinc. Gene expression changes were analyzed by microarray and qPCR, and incubation of VSMCs with blood plasma from zinc-deficient rats strongly changed the expression of >2500 genes, compared to incubation of cells with zinc-adequate rat plasma. We demonstrated that this effect was caused by a low-molecular-weight (∼2-kDa) zinc-regulated humoral factor but that changes in gene expression were mostly reversed by adding zinc back to zinc-deficient plasma. Strongly regulated genes were overrepresented in pathways associated with immune function and development. We conclude that zinc deficiency induces the production of a low-molecular-weight humoral factor whose influence on VSMC gene expression is blocked by plasma zinc. This factor is therefore under dual control by zinc.—Ou, O., Allen-Redpath, K., Urgast, D., Gordon, M.-J., Campbell, G., Feldmann, J., Nixon, G. F., Mayer, C.-D., Kwun, I.-S., and Beattie, J. H. Plasma zinc's alter ego is a low-molecular-weight humoral factor.</P>
Searches for small-scale anisotropies from neutrino point sources with three years of IceCube data
Aartsen, M.G.,Ackermann, M.,Adams, J.,Aguilar, J.A.,Ahlers, M.,Ahrens, M.,Altmann, D.,Anderson, T.,Arguelles, C.,Arlen, T.C.,Auffenberg, J.,Bai, X.,Barwick, S.W.,Baum, V.,Beatty, J.J.,Becker Tjus, J. North-Holland 2015 Astroparticle physics Vol.66 No.-
<P><B>Abstract</B></P> <P>Recently, IceCube found evidence for a diffuse signal of astrophysical neutrinos in an energy range of ∼ 60 TeV to the PeV-scale [1]. The origin of those events, being a key to understanding the origin of cosmic rays, is still an unsolved question. So far, analyses have not succeeded to resolve the diffuse signal into point-like sources. Searches including a maximum-likelihood-ratio test, based on the reconstructed directions and energies of the detected down- and up-going neutrino candidates, were also performed on IceCube data leading to the exclusion of bright point sources. In this paper, we present two methods to search for faint neutrino point sources in three years of IceCube data, taken between 2008 and 2011. The first method is an autocorrelation test, applied separately to the northern and southern sky. The second method is a multipole analysis, which expands the measured data in the northern hemisphere into spherical harmonics and uses the resulting expansion coefficients to separate signal from background. With both methods, the results are consistent with the background expectation with a slightly more sparse spatial distribution, corresponding to an underfluctuation. Depending on the assumed number of sources, the resulting upper limit on the flux per source in the northern hemisphere for an <SUP> E - 2 </SUP> energy spectrum ranges from ∼ 1.5 · <SUP> 10 - 8 </SUP> GeV/cm<SUP>2</SUP> s<SUP>−1</SUP>, in the case of one assumed source, to ∼ 4 · <SUP> 10 - 10 </SUP> GeV/cm<SUP>2</SUP> s<SUP>−1</SUP>, in the case of 3500 assumed sources.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We applied two methods to search for clusters of astrophysical neutrinos on background. </LI> <LI> Investigated both hemispheres separately and three different energy spectra. </LI> <LI> Saw underfluctuation consistent with background and set limits on astrophysical flux. </LI> <LI> Compared limits to recently found astrophysical flux to constrain number of sources. </LI> <LI> Excluded few sources of very hard energy spectra for seen astrophysical flux. </LI> </UL> </P>
SEARCHES FOR EXTENDED AND POINT-LIKE NEUTRINO SOURCES WITH FOUR YEARS OF ICECUBE DATA
Aartsen, M. G.,Ackermann, M.,Adams, J.,Aguilar, J. A.,Ahlers, M.,Ahrens, M.,Altmann, D.,Anderson, T.,Arguelles, C.,Arlen, T. C.,Auffenberg, J.,Bai, X.,Barwick, S. W.,Baum, V.,Beatty, J. J.,Tjus, J. Be IOP Publishing 2014 The Astrophysical journal Vol.796 No.2
<P>We present results on searches for point-like sources of neutrinos using four years of IceCube data, including the first year of data from the completed 86 string detector. The total livetime of the combined data set is 1373 days. For an E-2 spectrum, the observed 90% C. L. flux upper limits are similar to 10(-12) TeV-1 cm(-2) s(-1) for energies between 1 TeV and 1 PeV in the northern sky and similar to 10(-11) TeV-1 cm(-2) s(-1) for energies between 100 TeV and 100 PeV in the southern sky. This represents a 40% improvement compared to previous publications, resulting from both the additional year of data and the introduction of improved reconstructions. In addition, we present the first results from an all-sky search for extended sources of neutrinos. We update the results of searches for neutrino emission from stacked catalogs of sources and test five new catalogs; two of Galactic supernova remnants and three of active galactic nuclei. In all cases, the data are compatible with the background-only hypothesis, and upper limits on the flux of muon neutrinos are reported for the sources considered.</P>
SEARCH FOR PROMPT NEUTRINO EMISSION FROM GAMMA-RAY BURSTS WITH ICECUBE
Aartsen, M. G.,Ackermann, M.,Adams, J.,Aguilar, J. A.,Ahlers, M.,Ahrens, M.,Altmann, D.,Anderson, T.,Arguelles, C.,Arlen, T. C.,Auffenberg, J.,Bai, X.,Barwick, S. W.,Baum, V.,Bay, R.,Beatty, J. J.,Tju IOP Publishing 2015 ASTROPHYSICAL JOURNAL LETTERS - Vol.805 No.1
<P>We present constraints derived from a search of four years of IceCube data for a prompt neutrino flux from gammaray bursts (GRBs). A single low-significance neutrino, compatible with the atmospheric neutrino background, was found in coincidence with one of the 506 observed bursts. Although GRBs have been proposed as candidate sources for ultra-high-energy cosmic rays, our limits on the neutrino flux disfavor much of the parameter space for the latest models. We also find that no more than similar to 1% of the recently observed astrophysical neutrino flux consists of prompt emission from GRBs that are potentially observable by existing satellites.</P>
Observation of the cosmic-ray shadow of the Moon with IceCube
Aartsen, M. G.,Abbasi, R.,Abdou, Y.,Ackermann, M.,Adams, J.,Aguilar, J. A.,Ahlers, M.,Altmann, D.,Auffenberg, J.,Bai, X.,Baker, M.,Barwick, S. W.,Baum, V.,Bay, R.,Beatty, J. J.,Bechet, S.,Becker Tjus, American Physical Society 2014 PHYSICAL REVIEW D - Vol.89 No.10
The First Flight of the CREAM Silicon Charge Detector
N.H. Park,양종만,G. Bigongiari,박환배,김홍주,H.S. Ahn,박일흥,J. A. Jeon,J. H. Han,J. H. Hyun,J. J. Beatty,J. K. Lee,J. T. Childers,K. C. Kim,K. I. Seon,민경욱,L. Lutz,M. A. DuVernois,M. H. Lee,M.G. Begliesi,N. B. Co 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.2I
The CREAM (Cosmic Ray Energetics And Mass) experiment was constructed for the measurement of high-energy cosmic rays in the energy range between 1012 and 1015 eV. As a long duration balloon payload, the CREAM had its first successful flight in December 2004 from McMurdo Station, Antarctica. For the charge measurement of incident cosmic-ray particles entering the calorimeter module, a layer of the SCD (Silicon Charge Detector) made of 2912 silicon pixels was built with an active area of 779 × 795 mm2. This paper describes the performance of the SCD during the 2004-2005 flight.? The CREAM (Cosmic Ray Energetics And Mass) experiment was constructed for the measurement of high-energy cosmic rays in the energy range between 1012 and 1015 eV. As a long duration balloon payload, the CREAM had its first successful flight in December 2004 from McMurdo Station, Antarctica. For the charge measurement of incident cosmic-ray particles entering the calorimeter module, a layer of the SCD (Silicon Charge Detector) made of 2912 silicon pixels was built with an active area of 779 × 795 mm2. This paper describes the performance of the SCD during the 2004-2005 flight.?
ENERGY SPECTRA OF COSMIC-RAY NUCLEI AT HIGH ENERGIES
Ahn, H. S.,Allison, P.,Bagliesi, M. G.,Barbier, L.,Beatty, J. J.,Bigongiari, G.,Brandt, T. J.,Childers, J. T.,Conklin, N. B.,Coutu, S.,DuVernois, M. A.,Ganel, O.,Han, J. H.,Jeon, J. A.,Kim, K. C.,Lee, IOP Publishing 2009 The Astrophysical journal Vol.707 No.1
<P>We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment Cosmic-Ray Energetics And Mass (CREAM). The instrument included different particle detectors to provide redundant charge identification and measure the energy of CRs up to several hundred TeV. The measured individual energy spectra of C, O, Ne, Mg, Si, and Fe are presented up to similar to 10(14) eV. The spectral shape looks nearly the same for these primary elements and it can be fitted to an E(-2.66 +/- 0.04)power law in energy. Moreover, a new measurement of the absolute intensity of nitrogen in the 100-800 GeV/n energy range with smaller errors than previous observations, clearly indicates a hardening of the spectrum at high energy. The relative abundance of N/O at the top of the atmosphere is measured to be 0.080 +/- 0.025 (stat.) +/- 0.025 (sys.) at similar to 800 GeV/n, in good agreement with a recent result from the first CREAM flight.</P>