University of Texas at Dallas

About: University of Texas at Dallas is a education organization based out in Richardson, Texas, United States. It is known for research contribution in the topics: Population & Computer science. The organization has 14986 authors who have published 35589 publications receiving 1293714 citations. The organization is also known as: UT-Dallas & UT Dallas.

Potential transformations of chromium in natural waters

Abstract: A study has been conducted on the transformation of Cr(III) and Cr(VI) in simulated natural water conditions. It has been found that these forms are readily interconvertible under natural water conditions. The results of this study indicate that Cr(VI) is reduced by Fe(II), dissolved sulfides, and certain organic compounds with sulfhydryl groups, while Cr(III) is oxidized by a large excess of MnO2 and at a slow rate by Oz under conditions approximating those in natural waters. Based on the results of these studies, water quality standards for Cr should be based on total Cr rather than on Cr(VI), as has been frequently done in the past.

Plate tectonics on the Earth triggered by plume-induced subduction initiation

Abstract: High-resolution three-dimensional thermomechanical simulations of Earth's lithosphere indicate that mantle plumes could have initiated the first subduction zones, but only in the hotter early Earth for old oceanic plates. Taras Gerya and co-authors use high-resolution three-dimensional numerical thermomechanical models to show that mantle plumes could have initiated the first subduction zones. They find that several factors combine to trigger self-sustained subduction: a strong, negatively buoyant oceanic lithosphere, focused magmatic weakening and thinning of lithosphere above the plume, and lubrication of the slab interface by hydrated crust. They also conclude that plume-induced subduction was only feasible in the hotter early Earth for old oceanic plates, as younger plates would have favoured episodic lithospheric drips rather than self-sustained subduction and global plate tectonics. Scientific theories of how subduction and plate tectonics began on Earth—and what the tectonic structure of Earth was before this—remain enigmatic and contentious1. Understanding viable scenarios for the onset of subduction and plate tectonics2,3 is hampered by the fact that subduction initiation processes must have been markedly different before the onset of global plate tectonics because most present-day subduction initiation mechanisms require acting plate forces and existing zones of lithospheric weakness, which are both consequences of plate tectonics4. However, plume-induced subduction initiation5,6,7,8,9 could have started the first subduction zone without the help of plate tectonics. Here, we test this mechanism using high-resolution three-dimensional numerical thermomechanical modelling. We demonstrate that three key physical factors combine to trigger self-sustained subduction: (1) a strong, negatively buoyant oceanic lithosphere; (2) focused magmatic weakening and thinning of lithosphere above the plume; and (3) lubrication of the slab interface by hydrated crust. We also show that plume-induced subduction could only have been feasible in the hotter early Earth for old oceanic plates. In contrast, younger plates favoured episodic lithospheric drips rather than self-sustained subduction and global plate tectonics.

Passive immunization with a human monoclonal antibody protects hu-PBL-SCID mice against challenge by primary isolates of HIV-1

Abstract: How well antibodies can protect against disease due to HIV-1 infection remains a pivotal but unresolved issue with important implications for vaccine design and the use of prophylactic antibody to prevent infection after accidental exposure to the virus and to interrupt transmission of virus from mother to child. Strong doubts about the possible utility of antibodies in vivo have been raised because of the relative resistance of primary viruses to antibody neutralization in vitro. Primary viruses are likely to be close to the viruses transmitted during natural infection in humans. Vaccine studies have been of little value in assessing antibody efficacy in vivo because none of the strategies described to date have elicited significant neutralizing antibody responses to primary viruses (reviewed in ref. 1). Passive immunization studies are similarly hindered by the paucity of reagents able to neutralize primary viruses effectively2 and a single study has suggested some benefit3. Here we describe experiments to explore the ability of passive antibody to protect against primary virus challenge in hu-PBL-SCID mice. In this model, severe combined immunodeficient (SCID) mice are populated with human peripheral blood mononuclear celI (PBMCs) and infected with HIV-1 (ref. 4). We find that the potent neutralizing human monoclonal antibody lgG1b12 at high dose is able to completely protect even when given several hours after viral challenge. The results are encouraging for antibody-based postexposure prophylaxis and support the notion that antibody induction could contribute to an effective vaccine.