202 research outputs found

    Hot Isostatic Compaction of Graphite

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    The effects of temperature, pressure, and graphite starting material on the density, isotropy, and strength of dense graphite material prepared by hot isostatic compaction of graphite powders were examined. Process equipment was developed to permit operation at temperatures up to 2700 C under a 1600-atom isostatic pressure of inert gas . The isotropy of graphite compacts was determined by neutron diffraction. Relatively isotropic, high-purity graphites were produced having modest isotropic tensile strength and extremely high density (up to 2.24 g per cm3, or 99 per cent of theoretical)

    Sustainability Beliefs of First-year Students in Natural Resources

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    A crux of the environmental problem is change resistance and few college students possess the critical analysis and persuasive communication skills needed to engage in this dialogue. Furthermore, there is little appreciation among college students for the diversity of beliefs regarding sustainability issues. We surveyed students enrolled in a First-Year Experience class in Virginia Tech’s College of Natural Resources and Environment. We used the Dunlap and Van Liere New Environmental Paradigm (NEP) measurement scale to assess the individual student orientations toward nature and the environment. The students enrolled in this class had enrolled voluntarily based on their interest in the study of the environment or natural resources. Therefore, it was no surprise that the score reflected a belief orientation towards sustainability. Survey results allowed these first-year students to discover the range of opinion among members of a relatively homogeneous sample. The survey provided insights regarding the human-centered or eco-centered orientation of their student peers. We used these findings to encourage revision of a draft problem-solving essay. We plan further use of the NEP measurement scale in our curriculum and encourage its adoptions by instructors involved in pedagogy of sustainable thinking

    The Vehicle, November 1960, Vol. 3 no. 1

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    CONTENTS To the ReaderStaffpage 2 N’ = N : 1Donald C. Blairpage 3 ConsistencyDonald C. Blairpage 3 Unto MeLinda Kay Campbellpage 4 The Meek Shall InheritE. J. B. page 5 The Infinite QuestLarry W. Dudleypage 6 Dreamer’s DawnMike Hindmanpage 7 BirthNancy Coepage 7 The Lost DutchmanDonald C. Blairpage 8 W. E. Noonan IRobert S. Hodgepage 8 A Soldier’s OrdealDonald E. Shephardsonpage 9 Personal PossessionMary Beilpage 11 Thine The GloryDonald C. Blairpage 12 The ThornJan Holstlawpage 13 A Lord’s Day MorningLinda Campbellpage 14 Observations of a 6-Year-OldTom McPeakpage 15 Jewels of TimeJudith Jerintspage 16 LavenderE. J. B. page 16https://thekeep.eiu.edu/vehicle/1008/thumbnail.jp

    A Functional Role for ADAM10 in Human Immunodeficiency Virus Type-1 Replication

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    <p>Abstract</p> <p>Background</p> <p>Gene trap insertional mutagenesis was used as a high-throughput approach to discover cellular genes participating in viral infection by screening libraries of cells selected for survival from lytic infection with a variety of viruses. Cells harboring a disrupted <it>ADAM10 </it>(A Disintegrin and Metalloprotease 10) allele survived reovirus infection, and subsequently ADAM10 was shown by RNA interference to be important for replication of HIV-1.</p> <p>Results</p> <p>Silencing ADAM10 expression with small interfering RNA (siRNA) 48 hours before infection significantly inhibited HIV-1 replication in primary human monocyte-derived macrophages and in CD4<sup>+ </sup>cell lines. In agreement, ADAM10 over-expression significantly increased HIV-1 replication. ADAM10 down-regulation did not inhibit viral reverse transcription, indicating that viral entry and uncoating are also independent of ADAM10 expression. Integration of HIV-1 cDNA was reduced in ADAM10 down-regulated cells; however, concomitant 2-LTR circle formation was not detected, suggesting that HIV-1 does not enter the nucleus. Further, ADAM10 silencing inhibited downstream reporter gene expression and viral protein translation. Interestingly, we found that while the metalloprotease domain of ADAM10 is not required for HIV-1 replication, ADAM15 and γ-secretase (which proteolytically release the extracellular and intracellular domains of ADAM10 from the plasma membrane, respectively) do support productive infection.</p> <p>Conclusions</p> <p>We propose that ADAM10 facilitates replication at the level of nuclear trafficking. Collectively, our data support a model whereby ADAM10 is cleaved by ADAM15 and γ-secretase and that the ADAM10 intracellular domain directly facilitates HIV-1 nuclear trafficking. Thus, ADAM10 represents a novel cellular target class for development of antiretroviral drugs.</p

    GAS-PRESSURE BONDING OF ZIRCALOY-CLAD FLAT-PLATE URANIUM DIOXIDE FUEL ELEMENTS

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    A solid-state bonding technique involving the use of gas pressure at elevated temperatures was investigated for the preparation of compartmented Zircaloy-clad flat-plate uranium dioxide fuel elements. These investigations involved development of methods for the surface preparation and assembly of fuel- element components for bonding, determination of optimum bonding parameters, development of barrier coatings for uranium dioxide to prevent reaction with Zircaloy, and extensive testing and evaluation of the bonded fuel elements. During the course of this work, the process was continually modified and refined in an effort to improve the quality of the bonded element and decrease the cost of fabrication. The surface-preparation studies indicated that satisfactory bonding could be obtained consistently with both machined and belt-abraded components. Belt abrasion is more economical and was used as the standard technique in the development phases of the program. Initially the elements were assembled into a stainless steel or Ti-Namel envelope which was evacuated and sealed prior to bonding. Later studies showed that the quality of bonded elements could be improved and process costs decreased by edge welding the Zircaloy components to form a gastight assembly that was then bonded without use of a protective envelope. Further cost reductions were incorporated into the process by the use of piece Zircaloy components to form the picture frame. Optimum bending with a minimum core-to-cladding reaction was achieved by pressure bonding at 1500 to 1550 deg F for 4 hr using a helium gas pressure of 10,000 psi. A postbonding heat treatment for 5 min at 1850 deg F in a salt bath promoted additional grain growth at the bond interface during the alpha-to-beta transformation. Barrier layers of graphite. chronaium, iron. molybdenum, nickel, niobium, palladium, and various oxides were investigated to prevent reaction between the UO/sub 2/ core and Zircaloy cladding. Graphite, in the form of a sprayed and buffed coating, and chromium were found to be relatively effective barriers. The graphite coating was easy to apply and less expensive than a chromium electroplate. (auth

    The alignment of agricultural and nature conservation policies in the European Union.

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    Europe is a region of relatively high population density and productive agriculture subject to substantial government intervention under the Common Agricultural Policy (CAP). Many habitats and species of high conservation interest have been created by the maintenance of agricultural practices over long periods. These practices are often no longer profitable, and nature conservation initiatives require government support to cover the cost for them to be continued. The CAP has been reformed both to reduce production of agricultural commodities at costs in excess of world prices and to establish incentives for landholders to adopt voluntary conservation measures. A separate nature conservation policy has established an extensive series of protected sites (Natura 2000) that has, as yet, failed to halt the loss of biodiversity. Additional broader scale approaches have been advocated for conservation in the wider landscape matrix, including the alignment of agricultural and nature conservation policies, which remains a challenge. Possibilities for alignment include further shifting of funds from general support for farmers toward targeted payments for biodiversity goals at larger scales and adoption of an ecosystem approach. The European response to the competing demands for land resources may offer lessons globally as demands on rural land increase.This is the author accepted manuscript. The final version is available fromWiley via http://dx.doi.org/10.1111/cobi.1253

    The Effect of Various Restorative Materials on the Microhardness of Reparative Dentin

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    This study showed a statistically significant difference between the microhardness of reparative and primary dentin at both five- and eight-week intervals. Reparative dentin from occlusal trauma is harder than reparative dentin underlying a cavity preparation at the 99% level. No statistical difference was noted in the hardness of reparative dentin underlying different materials, but trends were observed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66484/2/10.1177_00220345800590020101.pd

    NIRCAM image simulations for NGST wavefront sensing

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    The Next Generation Space Telescope (NGST) will be a segmented, deployable, infrared-optimized 6.5m space telescope. Its active primary segments will be aligned, co-phased, and then fine-tuned in order to deliver image quality sufficient for the telescope's intended scientific goals. Wavefront sensing used to drive this tuning will come from the analysis of focussed and defocussed images taken with its near-IR science camera, NIRCAM. There is a pressing need to verify that this will be possible with the near-IR detectors that are still under development for NGST. We create simulated NIRCAM images to test the maintenance phase of this plan. Our simulations incorporate Poisson and electronics read noise, and are designed to be able to include various detector and electronics non-linearities. We present our first such simulation, using known or predicted properties of HAWAII HgCdTe focal plane array detectors. Detector effects characterized by the Independent Detector Testing Laboratory will be included as they become available. Simulating InSb detectors can also be done within this framework in future. We generate Point-Spread Functions (PSF's) for a segmented aperture geometry with various wavefront aberrations, and convolve this with typical galaxy backgrounds and stellar foregrounds. We then simulate up-the-ramp (MULTIACCUM in HST parlance) exposures with cosmic ray hits. We pass these images through the HST NICMOS `CALNICA' calibration task to filter out cosmic ray hits. The final images are to be fed to wavefront sensing software, in order to find the ranges of exposure times, filter bandpass, defocus, and calibration star magnitude required to keep the NGST image within its specifications
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