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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>
Ahn, H.S.,Allison, P.S.,Bagliesi, M.G.,Beatty, J.J.,Bigongiari, G.,Boyle, P.J.,Brandt, T.J.,Childers, J.T.,Conklin, N.B.,Coutu, S.,Duvernois, M.A.,Ganel, O.,Han, J.H.,Hyun, H.J.,Jeon, J.A.,Kim, K.C.,L North-Holland ; Elsevier Science Ltd 2008 Astroparticle physics Vol.30 No.3
We present new measurements of heavy cosmic-ray nuclei at high energies performed during the first flight of the balloon-borne cosmic-ray experiment Cosmic-Ray Energetics and Mass (CREAM). This instrument uses multiple charge detectors and a transition radiation detector to provide the first high accuracy measurements of the relative abundances of elements from boron to oxygen up to energies around 1TeV/n. The data agree with previous measurements at lower energies and show a relatively steep decline (∼E<SUP>-0.6</SUP> to E<SUP>-0.5</SUP>) at high energies. They further show the source abundance of nitrogen relative to oxygen is ∼10% in the TeV/n region.
Performance of a Dual Layer Silicon Charge Detector During CREAM Balloon Flight
Nam, S.,Ahn, H. S.,Allison, P.,Bagliesi, M. G.,Barbier, L.,Beatty, J. J.,Bigongiari, G.,Brandt, T. J.,Jeon, J. A.,Childers, J. T.,Conklin, N. B.,Coutu, S.,DuVernois, M. A.,Ganel, O.,Han, J. H.,Kim, K. IEEE 2007 IEEE transactions on nuclear science Vol.54 No.5
<P>The balloon-borne cosmic-ray experiment CREAM (Cosmic Ray Energetics And Mass) has completed two flights in Antarctica, with a combined duration of 70 days. One of the detectors in the payload is the SCD (silicon charge detector) that measures the charge of high energy cosmic rays. The SCD was assembled with silicon sensors. A sensor is a 4 × 4 array of DC-coupled PIN diode pixels with the total active area of 21 × 16 mm<SUP>2</SUP>. The SCD used during the first flight (December 2004-January 2005) was a single layer device, then upgraded to a dual layer device for the second flight (December 2005-January 2006), covering the total sensitive area of 779 × 795 mm<SUP>2</SUP>. Flight data demonstrated that adding a second layer improved SCD performance, showing excellent particle charge resolution. With a total dissipation of 136 W for the dual layer system, special care was needed in designing thermal paths to keep the detector temperature within its operational range. As a consequence, flight temperatures of the SCD, even at diurnal maximum were kept below 38°C. The SCD mechanical structure was designed to minimize the possibility of damage to the sensors and electronics from the impacts of parachute deployment and landing. The detector was recovered successfully following the flight and is being refurbished for the next flight in 2007. Details of construction, operation, and performance are presented for the dual-layered SCD flown for the second CREAM flight.</P>
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.?