1,775 research outputs found

    Effect of two-dimensional multiple sine-wave protrusions of the pressure and heat-transfer distributions for a flat plate at Mach 6

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    Effect of two dimensional multiple sine wave protrusions on pressure and heat transfer distributions for flat plate in hypersonic flo

    The Rb binding domain of HPV31 E7 is required to maintain high levels of DNA repair factors in infected cells

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    Human papillomaviruses (HPV) exhibit constitutive activation of ATM and ATR DNA damage response (DDR) pathways, which are required for productive viral replication. Expression of HPV31 E7 alone is sufficient to activate the DDR through an unknown mechanism. Here, we demonstrate that the E7 Rb binding domain is required to increase levels of many DDR proteins, including ATM, Chk2, Chk1, the MRN components MRE11, Rad50, and NBS1, as well as the homologous recombination repair proteins BRCA1 and Rad51. Interestingly, we have found that the increase in these DNA repair proteins does not occur solely at the level of transcription, but that E7 broadly increases the half-life of these DDR factors, a phenotype that is lost in the E7 Rb binding mutant. These data suggest that HPV-31 upregulates DNA repair factors necessary for replication by increasing protein half-life in a manner requiring the E7 Rb binding domain

    Co- variation in soil biodiversity and biogeochemistry in northern and southern Victoria Land, Antarctica

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    Data from six sites in Victoria Land (72–77°S) investigating co-variation in soil communities (microbial and invertebrate) with biogeochemical properties showthe influence of soil properties on habitat suitability varied among local landscapes as well as across climate gradients. Species richness of metazoan invertebrates (Nematoda, Tardigrada and Rotifera) was similar to previous descriptions in this region, though identification of three cryptic nematode species of Eudorylaimus through DNA analysis contributed to the understanding of controls over habitat preferences for individual species. Denaturing Gradient Gel Electrophoresis profiles revealed unexpectedly high diversity of bacteria. Distribution of distinct bacterial communities was associated with specific sites in northern and southern Victoria Land, as was the distribution of nematode and tardigrade species. Variation in soil metazoan communities was related to differences in soil organic matter, while bacterial diversity and community structure were not strongly correlated with any single soil property. There were no apparent correlations between metazoan and bacterial diversity, suggesting that controls over distribution and habitat suitability are different for bacterial and metazoan communities. Our results imply that top-down controls over bacterial diversity mediated by their metazoan consumers are not significant determinants of bacterial community structure and biomass in these ecosystems

    Environmental modification of yield and food composition of cowpea and leaf lettuce

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    Cowpea (Vigna unguiculata (L.) Walp.) and leaf lettuce (Lactuca sativa L.) are candidate species to provide ligume protein and starch or serve as a salad base for a nutritionally balanced and psychologically satisfying vegetarian diet in the Controlled Ecology Life Support System (CELSS). Various nutritional parameters are reported. Hydroponic leaf lettuce grew best under CO2 enrichment and photosynthetic photon flux (PPF) enhancement. Leaf protein content reached 36 percent with NH4(+) + NO3 nutrition; starch and free sugar content was as high as 7 or 8.4 percent of DW, respectively, for high PPF/CO2 enriched environments

    Structural Characterization of Rapid Thermal Oxidized Si\u3csub\u3e1−x−y\u3c/sub\u3eGe\u3csub\u3ex\u3c/sub\u3eC\u3csub\u3ey\u3c/sub\u3e Alloy Films Grown by Rapid Thermal Chemical Vapor Deposition

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    The structural properties of as-grown and rapid thermal oxidized Si1−x−yGexCy epitaxial layers have been examined using a combination of infrared, x-ray photoelectron, x-ray diffraction, secondary ion mass spectroscopy, and Raman spectroscopy techniques. Carbon incorporation into the Si1−x−yGexCy system can lead to compressive or tensile strain in the film. The structural properties of the oxidized Si1−x−yGexCy film depend on the type of strain (i.e., carbon concentration) of the as-prepared film. For compressive or fully compensated films, the oxidation process drastically reduces the carbon content so that the oxidized films closely resemble to Si1−xGex films. For tensile films, two broad regions, one with carbon content higher and the other lower than that required for full strain compensation, coexist in the oxidized films

    Teacher Training Workshop for Educators of Students Who Are Blind or Low Vision

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    The Independent Laboratory Access for the Blind (ILAB) project has developed a suite of speech accessible tools for students who are blind or low vision to use in secondary and postsecondary science laboratory classes. The following are illustrations of experiments designed to be used by educators to introduce them to the ILAB tools, and to demonstrate how these tools can be incorporated into standard laboratory experiments. Information about the Lawrence Hall of Science’s SAVI/SELPH curriculum is also discussed

    Mucinous adenocarcinoma of the bladder associated with long term suprapubic tube: A case report

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    BACKGROUND: Chronic indwelling catheters may induce histologic changes within the bladder, and these changes are sometimes pre-malignant. There are many documented cases of squamous cell carcinoma associated with indwelling catheters, but only three cases of catheter-associated adenocarcinoma have been reported. In this case report, we present radiographic findings of a case of mucinous adenocarcinoma of the bladder and suprapubic (SP) tract in a quadriplegic patient. CASE PRESENTATION: A 71-year-old male with a history of spinal cord injury presented with hematuria and SP discharge after SP catheterization for 51 years. CT urography was performed and revealed an irregular, infiltrative, and heterogeneous mass arising from the anterior bladder at the level of the suprapubic catheter and extending along the SP tube tract. Cystoscopy and biopsy revealed an adenocarcinoma of the anterior bladder and stoma with extensive associated mucin production and a background of acute and chronic inflammation. Surgical therapy included cystoprostatectomy, abdominal wall resection, ileal conduit creation, and abdominal wall reconstruction. The final diagnosis was a high-grade, T2a/N0/M0 (Stage II) mucinous adenocarcinoma of the bladder. There has been no evidence of tumor recurrence over the previous 5 years. CONCLUSION: Few cases of adenocarcinoma associated with long term indwelling catheter have been reported in the literature, and due to the rarity of this disease process, the prognosis with surgical therapy is not well known. The patient described herein has been free of recurrence for the previous five years, suggesting that surgery is a viable management option for these patients

    Validation of frequency and mode extraction calculations from time-domain simulations of accelerator cavities

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    The recently developed frequency extraction algorithm [G.R. Werner and J.R. Cary, J. Comp. Phys. 227, 5200 (2008)] that enables a simple FDTD algorithm to be transformed into an efficient eigenmode solver is applied to a realistic accelerator cavity modeled with embedded boundaries and Richardson extrapolation. Previously, the frequency extraction method was shown to be capable of distinguishing M degenerate modes by running M different simulations and to permit mode extraction with minimal post-processing effort that only requires solving a small eigenvalue problem. Realistic calculations for an accelerator cavity are presented in this work to establish the validity of the method for realistic modeling scenarios and to illustrate the complexities of the computational validation process. The method is found to be able to extract the frequencies with error that is less than a part in 10^5. The corrected experimental and computed values differ by about one parts in 10^$, which is accounted for (in largest part) by machining errors. The extraction of frequencies and modes from accelerator cavities provides engineers and physicists an understanding of potential cavity performance as it depends on shape without incurring manufacture and measurement costs

    HPV31 utilizes the ATR-Chk1 pathway to maintain elevated RRM2 levels and a replication-competent environment in differentiating Keratinocytes

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    Productive replication of human papillomaviruses (HPV) is restricted to the uppermost layers of the differentiating epithelia. How HPV ensures an adequate supply of cellular substrates for viral DNA synthesis in a differentiating environment is unclear. Here, we demonstrate that HPV31 positive cells exhibit increased dNTP pools and levels of RRM2, a component of the ribonucleotide reductase (RNR) complex, which is required for de novo synthesis of dNTPs. RRM2 depletion blocks productive replication, suggesting RRM2 provides dNTPs for viral DNA synthesis in differentiating cells. We demonstrate that HPV31 regulates RRM2 levels through expression of E7 and activation of the ATR-Chk1-E2F1 DNA damage response, which is essential to combat replication stress upon entry into S-phase, as well as for productive replication. Our findings suggest a novel way in which viral DNA synthesis is regulated through activation of ATR and Chk1 and highlight an intriguing new virus/host interaction utilized for viral replication
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