2,721 research outputs found

    The versatility of a truss mounted mobile transporter for in-space construction

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    The Mobile Transporter (MT) evolution from early erectable structures assembly activities is detailed. The MT operational features which are required to support astronauts performing on-orbit structure construction or spacecraft assembly functions are presented and discussed. Use of the MT to perform a variety of assembly functions is presented. Estimated EVA assembly times for a precision segmented reflector approximately 20 m in diameter are presented. The EVA/MT technique under study for construction of the reflector (and the entire spacecraft) is illustrated. Finally, the current status of development activities and test results involving the MT and Space Station structural assembly are presented

    A Platform for the Analysis of Qualitative and Quantitative Data about the Built Environment and its Users

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    There are many scenarios in which it is necessary to collect data from multiple sources in order to evaluate a system, including the collection of both quantitative data - from sensors and smart devices - and qualitative data - such as observations and interview results. However, there are currently very few systems that enable both of these data types to be combined in such a way that they can be analysed side-by-side. This paper describes an end-to-end system for the collection, analysis, storage and visualisation of qualitative and quantitative data, developed using the e-Science Central cloud analytics platform. We describe the experience of developing the system, based on a case study that involved collecting data about the built environment and its users. In this case study, data is collected from older adults living in residential care. Sensors were placed throughout the care home and smart devices were issued to the residents. This sensor data is uploaded to the analytics platform and the processed results are stored in a data warehouse, where it is integrated with qualitative data collected by healthcare and architecture researchers. Visualisations are also presented which were intended to allow the data to be explored and for potential correlations between the quantitative and qualitative data to be investigated

    GaN directional couplers for integrated quantum photonics

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    Large cross-section GaN waveguides are proposed as a suitable architecture to achieve integrated quantum photonic circuits. Directional couplers with this geometry have been designed with aid of the beam propagation method and fabricated using inductively coupled plasma etching. Scanning electron microscopy inspection shows high quality facets for end coupling and a well defined gap between rib pairs in the coupling region. Optical characterization at 800 nm shows single-mode operation and coupling-length-dependent splitting ratios. Two photon interference of degenerate photon pairs has been observed in the directional coupler by measurement of the Hong-Ou-Mandel dip with 96% visibility.Comment: 4 pages, 5 figure

    Tests of an alternate mobile transporter and extravehicular activity assembly procedure for the Space Station Freedom truss

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    Results are presented from a ground test program of an alternate mobile transporter (MT) concept and extravehicular activity (EVA) assembly procedure for the Space Station Freedom (SSF) truss keel. A three-bay orthogonal tetrahedral truss beam consisting of 44 2-in-diameter struts and 16 nodes was assembled repeatedly in neutral buoyancy by pairs of pressure-suited test subjects working from astronaut positioning devices (APD's) on the MT. The truss bays were cubic with edges 15 ft long. All the truss joint hardware was found to be EVA compatible. The average unit assembly time for a single pair of experienced test subjects was 27.6 sec/strut, which is about half the time derived from other SSF truss assembly tests. A concept for integration of utility trays during truss assembly is introduced and demonstrated in the assembly tests. The concept, which requires minimal EVA handling of the trays, is shown to have little impact on overall assembly time. The results of these tests indicate that by using an MT equipped with APD's, rapid EVA assembly of a space station-size truss structure can be expected

    String windings in the early universe

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    We study string dynamics in the early universe. Our motivation is the proposal of Brandenberger and Vafa, that string winding modes may play a key role in decompactifying three spatial dimensions. We model the universe as a homogeneous but anisotropic 9-torus filled with a gas of excited strings. We adopt initial conditions which fix the dilaton and the volume of the torus, but otherwise assume all states are equally likely. We study the evolution of the system both analytically and numerically to determine the late-time behavior. We find that, although dynamical evolution can indeed lead to three large spatial dimensions, such an outcome is not statistically favored.Comment: 26 pages, LaTeX, 4 eps figure

    Interleukin-1 induces rapid and transient expression of the c-fos proto-oncogene in isolated pancreatic islets and in purified β-cells

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    AbstractThe effect of interleukin-1β (IL-1) on expression of c-fos mRNA in isolated rat pancreatic islets was examined. Accumulation of c-fos mRNA was demonstrable after 30 min of exposure to IL-1, peaked by 60 min, and declined thereafter. Fluorescence-activated cell sorting (FACS) of dispersed islet cells was employed to localize the accumulation of c-fos mRNA to the β-cell. Cycloheximide did not influence the induction of c-fos mRNA by IL-1. Accumulation of c-fos mRNA therefore appears to be an early signal transduction event in the β-cell and a component of the cellular mechanism(s) by which IL-1 influences β-cell function

    DNA methylotype analysis in colorectal cancer

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    The methylation status of a gene promoter is considered to be an important mechanism for the development of many tumors, including colorectal cancer. Recent studies have shown that specific patterns of DNA methylation across multiple CpG loci in some human tumors are more informative than the detection of one single CpG locus in tumor genomes. In the present study, multiple CpG methylations of three genes (CDKN2A, DPYD and MLH1) were detected in DNA samples from patients with colorectal cancer using Pyrosequencing(®) technology. The bisulfite-converted DNA was amplified with a nested PCR and five or six CpG loci of each gene were assessed to determine DNA methylotype. Our data showed that 10/49 (20.4%), 6/48 (12.5%) and 14/49 (28.6%) of tumors were methylated with a DNA methylation level >0.2 in CDKN2A, DPYD and MLH1, respectively. Our study indicated a similar DNA methylation level across the multiple CpG loci for all three genes in the methylated tumor DNA samples, demonstrating a dichotomous trait in DNA methylation. The tumor DNA samples had unique DNA methylation patterns, which were high-degree and multiple-site methylation, but the normal DNA samples had no or a low-degree and dispersed single-site methylation. In addition, an inverse correlation in those methylated tumors was observed between DNA methylation and RNA expression for MLH1 (R(S)=−0.62, P=0.003), but not for CDKN2A and DPYD. In conclusion, distinctive DNA methylotypes exist in colorectal cancer and may depict a distinct biology in apparently homogeneous tumors

    Evaluation of the Group Lifestyle Balance Program in a Military Setting: An Investment Worth Expanding

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    Introduction: The Diabetes Prevention Program (DPP) demonstrated that lifestyle intervention programs were effective in preventing or delaying the onset of diabetes. The Group Lifestyle Balance (GLB) program translated the DPP curriculum into a 12-wk group intervention for those at risk for diabetes. This retrospective evaluation examined clinical outcomes for patients in the Diabetes Center of Excellence GLB program located at Wilford Hall Ambulatory Surgical Center from 2009 to 2013. Objectives included determining rates of retention, demographic characteristics of program completers, and changes in metabolic surrogates of disease prevalence. Study Design: Adults with prediabetes or metabolic syndrome (MetS) were referred to the GLB program. Updated participant metabolic data were collected at regular intervals during their participation. Results: During the 5-yr study, 704 patients attended the initial class. Overall, 52% of all participants completed the program with the greatest decline in participation occurring by the fourth week (30%). Baseline prevalence of conditions of interest for those who completed the program was prediabetes (93.2%), obesity (56.1%), and MetS (31.5%). GLB completers were older and retired (p \u3c 0.05). A significant number of active duty military members (44.9%, p \u3c 0.01, n = 53) dropped out of the program before the fourth week. Furthermore, those who completed the program saw a 2.0% reduction in prediabetes prevalence (p \u3c 0.001), obesity decreased by 8.7% (p \u3c 0.001), and MetS decreased by 6.8% (p \u3c 0.01). Significant differences were found for central obesity, triglycerides, and fasting blood sugar (p \u3c 0.001). Conclusions: The GLB program is a valuable DPP and was effective at improving clinical outcomes and reducing the incidence of prediabetes, obesity, and MetS for participants who completed the program. Every effort should be made to support and encourage GLB participants to complete the program
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