1,251 research outputs found
Initial Assessment of the Consolidation of Chalcogels into a Viable Waste Form
This report provides some preliminary data for the consolidation of chalcogen-based aerogels. The chalcogels tested to date at PNNL show great promise as iodine sorbents and preliminary consolidation research shows that they can be melted into a phase-pure glass at moderate temperatures. The preliminary consolidation experiments show that these materials might attack fused quartz so an alternative crucible material will likely need to be used to prevent this. The next steps will be to β’ Consider melting other chalcogel chemistries, e.g., Sn-Sb-S, Ge-Sn-S chalcogels β’ Consider melting chalcogels with adsorbed iodine to monitor iodine loss during melting β’ Optimize the consolidation temperatures to minimize the iodine loss and volatilizatio
Inhibition of interleukin-1Ξ²-stimulated collagenase and stromelysin expression in human tendon fibroblasts by epigallocatechin gallate ester
The medicinal benefits of green tea (Camellia sinensis) consumption have been attributed to bioavailable polyphenols, notably epigallocatechin gallate (EGCG). We have assessed the effects of EGCG and its non-esterified counterpart EGC on the expression of the collagenases, matrix metalloproteinases (MMP)-1 and -13, and the stromelysin, MMP-3, in human tendon-derived fibroblasts. Interleukin (IL)-1Γ increased MMP-1, -3 and -13 mRNA and output at least 30-fold. EGCG reduced this stimulation, by 20β30% at 2.5 Β΅M and more than 80% at 25 Β΅M, and had a smaller effect on MMP-2 mRNA expression, which was not stimulated by IL-1Γ. In all experiments EGCG was at least 10-fold more potent than EGC. EGCG reduced the stimulation of p54 JNK/SAPK phosphorylation by IL-1Γ but did not affect p38 MAPK phosphorylation, the degradation of I?B or the activating phosphorylation of NF?B. We conclude that EGCG reduces the IL-1-stimulated expression of both collagenase and stromelysin mRNA species, an effect which may be mediated by inhibition of the JNK/SAPK pathway. Taken together with previous reports of EGCG effects on the expression and/or activity of gelatinases and aggrecanases, our results underline the importance of extracellular matrix breakdown as a potential target for the actions of green tea polyphenols
Dechlorination Apparatus For Treating Chloride Salt Wastes: System Evaluation And Scale-Up
This paper describes an apparatus used to remove chlorine from chloride salt-based nuclear wastes from electrochemical reprocessing and/or chloride-based molten salt reactors (MSRs) through dechlorination by reacting the salts with ammonium dihydrogen phosphate (NH4H2PO4 or ADP) at temperatures up to 600 Β°C to produce NH4Cl as a byproduct. The benefits of removing the Cl from these salts include 37Cl recovery from Cl-based MSR salts, formation of UCl3 from the NH4Cl, as well as removal of Cl from the salts and conversion of the salt cations to oxides to allow for immobilization in a chemically durable iron phosphate waste form. This generation-2 system is an improvement over the generation-1 system and provides a means for scaling up salt throughput as well as NH4Cl recovery. The generation-2 system includes a five-zone furnace so the temperature of the four-zone gradient furnace can be tailored to control the location of NH4Cl condensation on a four-piece fused quartz off-gas system. Both ADP and NH4Cl decomposition reactions include the production of NH3 and acids (i.e., H3PO4 and HCl, respectively), so careful temperature control is needed during the ADP-salt reactions to maximize the NH4Cl production and minimize NH4Cl decomposition. In two sets of experiments run in the generation-1 and generation-2 apparatuses, NH4Cl yields were β₯5.5-fold higher for the new system compared to the original prototype system and the batch sizes can be β₯2.5-fold higher. In addition, some thermodynamic experiments evaluating the reactions of ADP + KCl as well as decomposition of pure NH4Cl were performed to assess the temperatures of the reactions and identify off-gas products
IL-18-induced expression of high-affinity IL-2R on murine NK cells is essential for NK-cell IFN-Ξ³ production during murine Plasmodium yoelii infection.
Early production of pro-inflammatory cytokines, including IFN-Ξ³, is essential for control of blood-stage malaria infections. We have shown that IFN-Ξ³ production can be induced among human natural killer (NK) cells by coculture with Plasmodium falciparum infected erythrocytes, but the importance of this response is unclear. To further explore the role of NK cells during malaria infection, we have characterized the NK-cell response of C57BL/6 mice during lethal (PyYM) or nonlethal (Py17XNL) P. yoelii infection. Ex vivo flow cytometry revealed that NK cells are activated within 24 h of Py17XNL blood-stage infection, expressing CD25 and producing IFN-Ξ³; this response was blunted and delayed during PyYM infection. CD25 expression and IFN-Ξ³ production were highly correlated, suggesting a causal relationship between the two responses. Subsequent in vitro experiments revealed that IL-18 signaling is essential for induction of CD25 and synergizes with IL-12 to enhance CD25 expression on splenic NK cells. In accordance with this, Py17XNL-infected erythrocytes induced NK-cell CD25 expression and IFN-Ξ³ production in a manner that is completely IL-18- and partially IL-12-dependent, and IFN-Ξ³ production is enhanced by IL-2. These data suggest that IL-2 signaling via CD25 amplifies IL-18- and IL-12-mediated NK-cell activation during malaria infection
Potential of Water and Salt Yields From Surface Runoff on Public Lands in the Price River Basin
The report examines possible sources of dissolved salts in the Price River basin. Ephemeral and intermittent streams contributed dissolved salts and are the focus of the study. Seven subwatersheds and the Price River at Heiner are investigated to examine the effects of existing watershed characteristics on runoff and dissolved salts production. Alternatley, the report examines the effects of specific land treatments on surface runoff quantity and quality. Various instrumentation techniques are evalauted to help improve future data collected capabilities in intermittent channels. The examination of the data reveals various trends that might be considered for further investigation in subsequent studies
Synthesis Of Dysprosium Oxychloride (DyOCl)
Dysprosium oxychloride, DyOCl, was synthesized using a simple hydrolysis method with DyCl3Β·6H2O. X-ray powder diffraction (XRD) data was used to determine the crystal structure. The DyOCl compound is isostructural to the matlockite (PbFCl) crystal structure and crystallizes in the tetragonal P4/nmm (#129) space group. The crystal structure contains the alternating cationic layers of (DyO)n and anionic layers of nClβ along the c-axis. The structural data including unit cell, volume, and density of DyOCl were compared to other rare-earth oxychloride data from the Inorganic Crystal Structure Database (ICSD) and our previous study on TbOCl. Fourier-transform infrared spectroscopy was performed on DyOCl and peaks observed at 543 and 744 cmβ1 were attributed to DyβO and DyβCl. Scanning electron microscopy analysis showed irregularly shaped crystals. Hot-stage XRD, thermogravimetry, as well as differential scanning calorimetry coupled to a gas chromatograph and a mass spectrometer (evolved gas analysis) were performed on DyCl3Β·6H2O to understand the phase transformation to DyOCl (and Dy2O3) as a function of temperature and time at temperature.
Graphic Abstract: DyOCl compound with the tetragonal P4/nmm space group is composed of the alternating layers of (DyO)n and nClβ along the c-axis
Hanford Low-Activity Waste Vitrification: A Review
This Paper Summarizes the Vast Body of Literature (Over 200 Documents) Related to Vitrification of the Low-Activity Waste (LAW) Fraction of the Hanford Tank Wastes. Details Are Provided on the Origins of the Hanford Tank Wastes that Resulted from Nuclear Operations Conducted between 1944 and 1989 to Support Nuclear Weapons Production. Waste Treatment Processes Are Described, Including the Baseline Process to Separate the Tank Waste into LAW and High-Level Waste Fractions, and the LAW Vitrification Facility Being Started at Hanford. Significant Focus is Placed on the Glass Composition Development and the Property-Composition Relationships for Hanford LAW Glasses. Glass Disposal Plans and Criteria for Minimizing Long-Term Environmental Impacts Are Discussed Along with Research Perspectives
Initial Laboratory-Scale Melter Test Results for Combined Fission Product Waste
This report describes the methods and results used to vitrify a baseline glass, CSLNTM-C-2.5 in support of the AFCI (Advanced Fuel Cycle Initiative) using a Quartz Crucible Scale Melter at the Pacific Northwest National Laboratory. Document number AFCI-WAST-PMO-MI-DV-2009-000184
Activation of Transforming Growth Factor Ξ² by Malaria Parasite-derived Metalloproteinases and a Thrombospondin-like Molecule
Much of the pathology of malaria is mediated by inflammatory cytokines (such as interleukin 12, interferon Ξ³, and tumor necrosis factor Ξ±), which are part of the immune response that kills the parasite. The antiinflammatory cytokine transforming growth factor (TGF)-Ξ² plays a crucial role in preventing the severe pathology of malaria in mice and TGF-Ξ² production is associated with reduced risk of clinical malaria in humans. Here we show that serum-free preparations of Plasmodium falciparum, Plasmodium yoelii 17XL, and Plasmodium berghei schizont-infected erythrocytes, but not equivalent preparations of uninfected erythrocytes, are directly able to activate latent TGF-Ξ² (LatTGF-Ξ²) in vitro. Antibodies to thrombospondin (TSP) and to a P. falciparum TSP-related adhesive protein (PfTRAP), and synthetic peptides from PfTRAP and P. berghei TRAP that represent homologues of TGF-Ξ² binding motifs of TSP, all inhibit malaria-mediated TGF-Ξ² activation. Importantly, TRAP-deficient P. berghei parasites are less able to activate LatTGF-Ξ² than wild-type parasites and their replication is attenuated in vitro. We show that activation of TGF-Ξ² by malaria parasites is a two step process involving TSP-like molecules and metalloproteinase activity. Activation of LatTGF-Ξ² represents a novel mechanism for direct modulation of the host response by malaria parasites
IFN-Ξ³-producing CD4+ T cells promote experimental cerebral malaria by modulating CD8+ T cell accumulation within the brain.
It is well established that IFN-Ξ³ is required for the development of experimental cerebral malaria (ECM) during Plasmodium berghei ANKA infection of C57BL/6 mice. However, the temporal and tissue-specific cellular sources of IFN-Ξ³ during P. berghei ANKA infection have not been investigated, and it is not known whether IFN-Ξ³ production by a single cell type in isolation can induce cerebral pathology. In this study, using IFN-Ξ³ reporter mice, we show that NK cells dominate the IFN-Ξ³ response during the early stages of infection in the brain, but not in the spleen, before being replaced by CD4(+) and CD8(+) T cells. Importantly, we demonstrate that IFN-Ξ³-producing CD4(+) T cells, but not innate or CD8(+) T cells, can promote the development of ECM in normally resistant IFN-Ξ³(-/-) mice infected with P. berghei ANKA. Adoptively transferred wild-type CD4(+) T cells accumulate within the spleen, lung, and brain of IFN-Ξ³(-/-) mice and induce ECM through active IFN-Ξ³ secretion, which increases the accumulation of endogenous IFN-Ξ³(-/-) CD8(+) T cells within the brain. Depletion of endogenous IFN-Ξ³(-/-) CD8(+) T cells abrogates the ability of wild-type CD4(+) T cells to promote ECM. Finally, we show that IFN-Ξ³ production, specifically by CD4(+) T cells, is sufficient to induce expression of CXCL9 and CXCL10 within the brain, providing a mechanistic basis for the enhanced CD8(+) T cell accumulation. To our knowledge, these observations demonstrate, for the first time, the importance of and pathways by which IFN-Ξ³-producing CD4(+) T cells promote the development of ECM during P. berghei ANKA infection
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