323 research outputs found

    Bostonia: The Boston University Alumni Magazine. Volume 20

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    Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

    Scaling behavior of self-avoiding walks on percolation clusters

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    The scaling behavior of self-avoiding walks (SAWs) on the backbone of percolation clusters in two, three and four dimensions is studied by Monte Carlo simulations. We apply the pruned-enriched Rosenbluth chain-growth method (PERM). Our numerical results bring about the estimates of critical exponents, governing the scaling laws of disorder averages of the end-to-end distance of SAW configurations. The effects of finite-size scaling are discussed as well.Comment: 6 page

    Adhesion Molecule Expression in Polymorphic Light Eruption

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    Endothelial leukocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) are cytokine-regulated cell-surface Ieukocyte adhesion molecules. We have investigated the in vivo kinetics and pattern of expression of these adhesion molecules in relation to tissue accumulation of leukocytes in the photodermatosis, polymorphic light eruption (PMLE), which is characterized by dense perivascular leukocytic infiltration. Immunohistology was performed on biopsies taken at varying time points from PMLE lesions induced in 11 subjects by suberythemal solar simulated irradiation. Vascular endothelial ELAM-1 expression was first observed at 5 h, maximal at 24 to 72 h, and remained elevated at 6 d. VCAM-1, minimally expressed in control skin, was induced above background levels on endothelium and some perivascular cells after 24h and maintained at 6 d. Endothelial cell ICAM-1 expression was increased above control levels at 72h and 6 d. Keratinocyte ICAM-1 expression, most marked overlying areas of dermal leukocytic infiltration, began at 5h and was strong at 72h and 6 d. In addition to lymphocytes, significant number of neutrophils of but not eosinophils were detected in the dermal leukocytic infiltrate that appeared at 5h and persisted at 6 d. The pattern of adhesion molecule expression that we have observed is similar to that seen in normal skin during a delayed hypersensitivity reaction: These observations support an immunologic basis for PMLE

    Anti-Cocaine Compositions and Treatment

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    Embodiments of the invention disclosed herein generally relate to anti-cocaine therapeutics. Specifically, some embodiments of the invention relate to highly efficient, thermostable, and long-lasting cocaine esterase (CocE) mutants that can protect against the toxic and reinforcing effects of cocaine in subjects. Provided herein are mutant CocE polypeptides displaying thermostable esterase activity. Also provided are methods of treating cocaine-induced conditions in a subject in need via administration of mutant CocE as well as methods for high-throughput screening of candidate esterase polypeptides

    Anti-Cocaine Compositions and Treatment

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    Embodiments of the invention disclosed herein generally relate to anti-cocaine therapeutics. Specifically, some embodiments of the invention relate to highly efficient, thermostable, and long-lasting cocaine esterase (CocE) mutants that can protect against the toxic and reinforcing effects of cocaine in subjects. Provided herein are mutant CocE polypeptides displaying thermostable esterase activity. Also provided are methods of treating cocaine-induced conditions in a subject in need via administration of mutant CocE as well as methods for high-throughput screening of candidate esterase polypeptides

    A new anode material for oxygen evolution in molten oxide electrolysis

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    Molten oxide electrolysis (MOE) is an electrometallurgical technique that enables the direct production of metal in the liquid state from oxide feedstock and compared with traditional methods of extractive metallurgy offers both a substantial simplification of the process and a significant reduction in energy consumption. MOE is also considered a promising route for mitigation of CO[subscript 2] emissions in steelmaking, production of metals free of carbon, and generation of oxygen for extra-terrestrial exploration. Until now, MOE has been demonstrated using anode materials that are consumable (graphite for use with ferro-alloys and titanium) or unaffordable for terrestrial applications (iridium for use with iron). To enable metal production without process carbon, MOE requires an anode material that resists depletion while sustaining oxygen evolution. The challenges for iron production are threefold. First, the process temperature is in excess of 1,538 degrees Celsius. Second, under anodic polarization most metals inevitably corrode in such conditions. Third, iron oxide undergoes spontaneous reduction on contact with most refractory metals and even carbon. Here we show that anodes comprising chromium-based alloys exhibit limited consumption during iron extraction and oxygen evolution by MOE. The anode stability is due to the formation of an electronically conductive solid solution of chromium(iii) and aluminium oxides in the corundum structure. These findings make practicable larger-scale evaluation of MOE for the production of steel, and potentially provide a key material component enabling mitigation of greenhouse-gas emissions while producing metal of superior metallurgical quality.American Iron and Steel Institut

    Brane Baldness vs. Superselection Sectors

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    The search for intersecting brane solutions in supergravity is a large and profitable industry. Recently, attention has focused on finding localized forms of known `delocalized' solutions. However, in some cases, a localized version of the delocalized solution simply does not exist. Instead, localized separated branes necessarily delocalize as the separation is removed. This phenomenon is related to black hole no-hair theorems, i.e. `baldness.' We continue the discussion of this effect and describe how it can be understood, in the case of Dirichlet branes, in terms of the corresponding intersection field theory. When it occurs, it is associated with the quantum mixing of phases and lack of superselection sectors in low dimensional field theories. We find surprisingly wide agreement between the field theory and supergravity both with respect to which examples delocalize and with respect to the rate at which this occurs.Comment: 26 pages, ReVTeX, 2 figures, reference added, version to appear in PR
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