3,066 research outputs found
Pulsed Corona Discharge for Oxidation of Gaseous Elemental Mercury
Positive pulsed corona discharge has been applied for the oxidation of gaseous elemental mercury (Hg0) from a simulated flue gas. The oxidation of Hg0 to HgO and HgCl2 can significantly enhance the mercury removal from flue gas. At a gas condition of O2 (10%), H2O (3%), and N2 (balance), Hg0 oxidation efficiency of 84% was achieved at an input energy density of 45 J/l. The presence of NO, however, hinders Hg0 oxidation due to the preferential reaction of NO with O and O3. On the contrary, SO2 shows little effect on Hg0 oxidation due to its preferential reaction with OH. It has been also observed that the HCl in gas stream can be dissociated to Cl and Cl2 and can induce additional Hg0 oxidation to HgCl2
The seagoing scientist's toolbox: integrated methods for quality control of marine geophysical data at sea
We announce a new and integrated system for planning and executing marine geophysical surveys and for scrutinizing and visualizing incoming shipboard data. The system incorporates free software designed for use by scientists and shipboard operators and pertains to underway geophysics and multibeam sonar surveys. Regarding underway data, a crucial first step in the approach is to reduce and merge incoming center beam depth, gravity, and towed magnetic data with navigation, then reformat to the standard exchange format. We are then able to apply established quality control methods including along-track and cross-track analyses to identify error sources and to incrementally build the candidate archive file as new data are acquired. Regarding multibeam data, these are subjected to both an automated error removal scheme for quick visualization and to subsequent ping editing in detail. The candidate archive file and sonar data are automatically and periodically updated and adapted for display in Google Earth, wherein survey planning is also carried out. Data layers are also updated automatically in Google Earth, allowing scientists to focus on visual inspection and interpretation of incoming data. By visualizing underway and sonar data together with reference gravity, magnetic, and bathymetry grids in Google Earth, data familiarity is enhanced and the likelihood of noticing extreme errors increased. We hope scientists will embrace these techniques so that each data set being submitted to a data repository is vetted by the seagoing science party.U.S. National Science FoundationNational Science Foundation (NSF) [1458964, 1558403]Korea Institute of Ocean Science and Technology [PM59941, PM60321
All-sky Galactic radiation at 45 MHz and spectral index between 45 and 408 MHz
Aims: We study the Galactic large-scale synchrotron emission by generating a
reliable all-sky spectral index map and temperature map at 45 MHz. Methods: We
use our observations, the published all-sky map at 408 MHz, and a
bibliographical compilation to produce a map corrected for zero-level offset
and extragalactic contribution. Results: We present full sky maps of the
Galactic emission at 45 MHz and the Galactic spectral index between 45 and 408
MHz with an angular resolution of 5\degs. The spectral index varies between 2.1
and 2.7, reaching values below 2.5 at low latitude because of thermal free-free
absorption and its maximum in the zone next to the Northern Spur.Comment: A&A accepte
BACE1 activity impairs neuronal glucose oxidation:rescue by beta-hydroxybutyrate and lipoic acid
Glucose hypometabolism and impaired mitochondrial function in neurons have been suggested to play early and perhaps causative roles in Alzheimer's disease (AD) pathogenesis. Activity of the aspartic acid protease, beta-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1), responsible for beta amyloid peptide generation, has recently been demonstrated to modify glucose metabolism. We therefore examined, using a human neuroblastoma (SH-SY5Y) cell line, whether increased BACE1 activity is responsible for a reduction in cellular glucose metabolism. Overexpression of active BACE1, but not a protease-dead mutant BACE1, protein in SH-SY5Y cells reduced glucose oxidation and the basal oxygen consumption rate, which was associated with a compensatory increase in glycolysis. Increased BACE1 activity had no effect on the mitochondrial electron transfer process but was found to diminish substrate delivery to the mitochondria by inhibition of key mitochondrial decarboxylation reaction enzymes. This BACE1 activity-dependent deficit in glucose oxidation was alleviated by the presence of beta hydroxybutyrate or α-lipoic acid. Consequently our data indicate that raised cellular BACE1 activity drives reduced glucose oxidation in a human neuronal cell line through impairments in the activity of specific tricarboxylic acid cycle enzymes. Because this bioenergetic deficit is recoverable by neutraceutical compounds we suggest that such agents, perhaps in conjunction with BACE1 inhibitors, may be an effective therapeutic strategy in the early-stage management or treatment of AD
Photon-Photon Scattering, Pion Polarizability and Chiral Symmetry
Recent attempts to detect the pion polarizability via analysis of
measurements are examined. The connection
between calculations based on dispersion relations and on chiral perturbation
theory is established by matching the low energy chiral amplitude with that
given by a full dispersive treatment. Using the values for the polarizability
required by chiral symmetry, predicted and experimental cross sections are
shown to be in agreement.Comment: 21 pages(+10 figures available on request), LATEX, UMHEP-38
Light cluster production in intermediate energy heavy-ion collisions induced by neutron-rich nuclei
The coalescence model based on nucleon distribution functions from an
isospin-dependent transport model is used to study the production of light
clusters such as deuteron, triton, and He from heavy-ion collisions
induced by neutron-rich nuclei at intermediate energies. It is found that the
emission time of light clusters depends on their masses. For clusters with the
same momentum per nucleon, heavier ones are emitted earlier. Both the yield and
energy spectrum of light clusters are sensitive to the density dependence of
nuclear symmetry energy, with more light clusters produced in the case of a
stiff symmetry energy. On the other hand, effects due to the stiffness of the
isoscalar part of nuclear equation of state and the medium dependence of
nucleon-nucleon cross sections on light cluster production are unimportant. We
have also studied the correlation functions of clusters, and they are affected
by the density dependence of nuclear symmetry energy as well, with the stiff
symmetry energy giving a stronger anti-correlation of light clusters,
particularly for those with large kinetic energies. Dependence of light cluster
production on the centrality and incident energy of heavy ion collisions as
well as the mass of the reaction system is also investigated.Comment: Revised version, typos corrected and discussions added, 14 pages, 15
figures, 1 table, REVTeX4.
Immunoreactivity of CD99 in Non-Hodgkin's Lymphoma: Unexpected Frequent Expression in ALK-positive Anaplastic Large Cell Lymphoma
To verify the spectrum of CD99-expressing lymphoid malignancy, an immunohistochemical study for CD99 was carried out in 182 cases of non-Hodgkin's lymphoma, including 21 lymphoblastic lymphomas, 11 small lymphocytic lymphomas, 9 mantle cell lymphomas, 12 follicular lymphomas, 37 diffuse large B cell lymphomas, 18 Burkitt's lymphomas, 28 NK/T-cell lymphomas, 8 angioimmunoblastic T-cell lymphomas, 23 peripheral T-cell lymphomas, unspecified, and 15 systemic anaplastic large cell lymphomas. CD99 was positive in all T-lymphoblastic lymphomas and in 60% of B-lymphoblastic lymphomas. Majority of T and NK cell lymphomas were negative for CD99, except anaplastic large cell lymphomas (ALCLs). Eight of 15 cases (54%) of ALCLs reacted with anti CD99 antibody. Seven of 10 (70%) ALK positive ALCLs expressed CD99, whereas only 1 of 5 (20%) ALK negative ALCLs were positive. Of the mature B-cell lymphomas, 5.4% (2/37) of diffuse large B cell lymphomas and 11.1% (2/18) of Burkitt's lymphomas expressed CD99. In conclusion, CD99 is infrequently expressed in mature B and T cell lymphomas, except ALK-positive ALCL. High expression of CD99 in ALK-positive ALCL is unexpected finding and its biologic and clinical significances have yet to be clarified
Desferrioxamine decreases NAD redox potential of intact red blood cells: evidence for desferrioxamine as an inducer of oxidant stress in red blood cells
BACKGROUND: Desferrioxamine (DFO) is an important iron chelating agent. It has also been thought of as an agent with anti-oxidant potential as it chelates ferric iron in various parts of the body. However, there is evidence suggesting that it may paradoxically affect red blood cells (RBC) by inducing intracellular oxidant stress. To further understand the mechanism of DFO's interaction with RBC, we conducted a study to determine the effect of DFO upon RBC's redox status. METHODS: We examined NAD redox potential in intact RBC (N = 5) incubated with DFO. RBC were incubated with 6 mM DFO for 2 hours. RESULTS: Significant decreases in NAD redox potential were observed after incubation of RBC with 6 mM DFO. The mean decrease was 10.01 ± 1.98% (p < 0.0004). CONCLUSIONS: The data confirm the oxidant effect of DFO on RBC
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