1,437 research outputs found

    EMI protection design guidance

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    This EMI Protection Design Guidelines report has been prepared as a guide for use by ALSEP experiment fabrication and subsystem designers.prepared by J. Whiteford, R. L. Lewis

    The CMV early enhancer/chicken β actin (CAG) promoter can be used to drive transgene expression during the differentiation of murine embryonic stem cells into vascular progenitors

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    <p>Abstract</p> <p>Background</p> <p>Mouse embryonic stem cells cultured <it>in vitro </it>have the ability to differentiate into cells of the three germ layers as well as germ cells. The differentiation mimics early developmental events, including vasculogenesis and early angiogenesis and several differentiation systems are being used to identify factors that are important during the formation of the vascular system. Embryonic stem cells are difficult to transfect, while downregulation of promoter activity upon selection of stable transfectants has been reported, rendering the study of proteins by overexpression difficult.</p> <p>Results</p> <p>CCE mouse embryonic stem cells were differentiated on collagen type IV for 4–5 days, Flk1<sup>+ </sup>mesodermal cells were sorted and replated either on collagen type IV in the presence of VEGFA to give rise to endothelial cells and smooth muscle cells or in collagen type I gels for the formation of vascular tubes. The activity of the CMV and β-actin promoters was downregulated during selection of stable transfectants and during differentiation to the Flk1 stage, while the CMV immediate enhancer/β-actin promoter in the pCAGIPuro-GFP vector led to 100% of stably transfected undifferentiated and differentiated cells expressing GFP. To further test this system we expressed syndecan-2 and -4 in these cells and demonstrated high levels of transgene expression in both undifferentiated cells and cells differentiated to the Flk1 stage.</p> <p>Conclusion</p> <p>Vectors containing the CAG promoter offer a valuable tool for the long term expression of transgenes during stem cell differentiation towards mesoderm, while the CMV and β-actin promoters lead to very poor transgene expression during this process.</p

    Updated Atomic Data and Calculations for X-ray Spectroscopy

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    We describe the latest release of AtomDB, version 2.0.2, a database of atomic data and a plasma modeling code with a focus on X-ray astronomy. This release includes several major updates to the fundamental atomic structure and process data held within AtomDB, incorporating new ionization balance data, state-selective recombination data, and updated collisional excitation data for many ions, including the iron L-shell ions from Fe+16^{+16} to Fe+23^{+23} and all of the hydrogen- and helium-like sequences. We also describe some of the effects that these changes have on calculated emission and diagnostic line ratios, such as changes in the temperature implied by the He-like G-ratios of up to a factor of 2.Comment: Submitted to ApJ, 12 pages, 9 figure

    Atomic data from the IRON Project. I. Electron-impact scattering of Fe17+ using <I>R</I>-matrix theory with intermediate coupling

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    We present results for electron-impact excitation of F-like Fe calculated using R-matrix theory where an intermediate-coupling frame transformation (ICFT) is used to obtain level-resolved collision strengths. Two such calculations are performed, the first expands the target using 2s2 2p5, 2s 2p6, 2s2 2p4 3l, 2s 2p5 3l, and 2p6 3l configurations while the second calculation includes the 2s2 2p4 4l, 2s 2p5 4l, and 2p6 4l configurations as well. The effect of the additional structure in the latter calculation on the n=3 resonances is explored and compared with previous calculations. We find strong resonant enhancement of the effective collision strengths to the 2s2 2p4 3s levels. A comparison with a Chandra X-ray observation of Capella shows that the n=4 R-matrix calculation leads to good agreement with observation</p

    Beyond clinical trials: extending the role of the clinical research nurse into social care and homeless research

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    Aim: Clinical research nurses work at the fulcrum of clinical trials with clearly defined roles and responsibilities. In England, the National Institute for Health Research (the main funder of health research) has broadened its scope to encompass social care research. The expectation is that clinical research nurses will expand their skill set to support these new studies, many of which will employ qualitative and mixed methods. This discussion paper explores the challenges of facilitating this clinical academic workforce development through a case study of a homeless health and social care research project. This was one of the first studies to engage clinical research nurses in this new and expanded role. Background: Much of what is known about the research nurse workforce has been generated through studies of clinical trials in oncology. The ‘caring-recruiting’ dichotomy has been used as a heuristic device for identifying workforce issues that can impact on study delivery such as how intense pressure to recruit study participants leads to low job satisfaction. Design: This case study reflects on the authors' experiences of employing a clinical research nurse in a social care research project concerned with the discharge of homeless people from hospital. The ‘caring-recruiting’ dichotomy is used to generate new information about the relationship between workforce development and the successful delivery of social care research. Conclusion: The case study illuminates how social care research can generate different pressures and ethical challenges for research nurses. The time and skill it took to recruit study participants identified as ‘hard to reach’ was suggestive of the need to move beyond performance measures that prioritise recruitment metrics. The need for different types of staff supervision and training was also warranted as supporting study participants who were homeless was often distressing, leading to professional boundary issues. Relevance to workforce development: This study highlights that performance management, training and supervisory arrangements must be tailored to the characteristics of each new study coming onto the portfolio to ensure research nurses are fully supported in this new and expanded role

    The National Food Consumption Survey (NFCS): South Africa, 1999

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    Objective: The aim of the National Food Consumption Survey (NFCS) in South Africa was to determine the nutrient intakes and anthropometric status of children (1-9 years old), as well as factors that influence their dietary intake. Design: This was a cross-sectional survey of a nationally representative sample of all children aged 1-9 years in South Africa. A nationally representative sample with provincial representation was selected using 1996 Census information. Subjects: Of the 3120 children who were originally sampled data were obtained from 2894, a response rate of 93%. Methods: The sociodemographic status of each household was assessed by a questionnaire. Dietary intake was assessed by means of a 24-hour recall and a food-frequency questionnaire from the caregivers of the children. Food purchasing practices were determined by means of a food procurement questionnaire. Hunger was assessed by a modified hunger scale questionnaire. Nutritional status was determined by means of anthropometric measurements: height, weight, head circumference and arm circumference. Results: At the national level, stunting (height-for-age below minus two standard deviations (&lt; -2SD) from the reference median) was by far the most common nutritional disorder, affecting nearly one in five children. The children least affected (17%) were those living in urban areas. Even with regard to the latter, however, children living in informal urban areas were more severely affected (20%) compared with those living in formal urban areas (16%). A similar pattern emerged for the prevalence of underweight (weight-for-age &lt; -2SD), with one in 10 children being affected at the national level. Furthermore, one in 10 (13%) and one in four (26%) children aged 1-3 years had an energy intake less than half and less than two-thirds of their daily energy needs, respectively. For South African children as a whole, the intakes of energy, calcium, iron, zinc, selenium, vitamins A, D, C and E, riboflavin, niacin, vitamin B6 and folic acid were below two-thirds of the Recommended Dietary Allowances. At the national level, data from the 24-hour recalls indicated that the most commonly consumed food items were maize, sugar, tea, whole milk and brown bread. For South African children overall, one in two households (52%) experienced hunger, one in four (23%) were at risk of hunger and only one in four households (25%) appeared food-secure. Conclusion: The NFCS indicated that a large majority of households were food-insecure and that energy deficit and micronutrient deficiencies were common, resulting in a high prevalence of stunting. These results were used as motivation for the introduction of mandatory fortification in South Africa. © The Authors 2005.Conference Pape

    Ionization state, excited populations and emission of impurities in dynamic finite density plasmas: I. The generalized collisional-radiative model for light elements

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    The paper presents an integrated view of the population structure and its role in establishing the ionization state of light elements in dynamic, finite density, laboratory and astrophysical plasmas. There are four main issues, the generalized collisional-radiative picture for metastables in dynamic plasmas with Maxwellian free electrons and its particularizing to light elements, the methods of bundling and projection for manipulating the population equations, the systematic production/use of state selective fundamental collision data in the metastable resolved picture to all levels for collisonal-radiative modelling and the delivery of appropriate derived coefficients for experiment analysis. The ions of carbon, oxygen and neon are used in illustration. The practical implementation of the methods described here is part of the ADAS Project

    The white‐rot fungus, Phanerochaete chrysosporium, under combinatorial stress produces variable oil profiles following analysis of secondary metabolites

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    From Wiley via Jisc Publications RouterHistory: received 2020-06-29, rev-recd 2020-11-10, accepted 2021-01-15, pub-electronic 2021-02-25, pub-print 2021-09Article version: VoRPublication status: PublishedFunder: Global Challenges Research Fund 2018‐19 GCRF Accelerator ‐ Adding value to agricultural waste through conversion to value added products; Grant(s): G.LFGC.001.EXPAbstract: Aims: The effects of combinatorial stress on lipid production in Phanerochaete chrysosporium remain understudied. This species of white‐rot fungi was cultivated on solid‐state media while under variable levels of known abiotic and biotic stressors to establish the effect upon fungal oil profiles. Methods and Results: Environmental stressors induced upon the fungus included the following: temperature, nutrient limitation and interspecies competition to assess impact upon oil profiles. Fatty acid type and its concentration were determined using analytical methods of gas chromatography and mass spectrometry. Growth rate under stress was established using high‐performance liquid chromatography with ergosterol as the biomarker. Fungi grown on solid‐state agar were able to simultaneously produce short‐ and long‐chain fatty acids which appeared to be influenced by nutritional composition as well as temperature. Addition of nitrogen supplements increased the growth rate, but lipid dynamics remained unchanged. Introducing competition‐induced stress had significantly altered the production of certain fatty acids beyond that of the monoculture while under nutrient‐limiting conditions. Linoleic acid concentrations, for example, increased from an average of 885 ng μl−1 at monoculture towards 13 820 ng μl−1 at co‐culture, following 7 days of incubation. Conclusions: Interspecies competition produced the most notable impact on lipid production for solid‐state media cultivated fungi while the addition of nitrogen supplementation presented growth and lipid accumulation to be uncorrelated. Combinatorial stress therefore influences the yield of overall lipid production as well as the number of intermediate fatty acids produced, deriving similar oil profiles to the composition of vegetable and fish oils. Significance and Impact of the Study: Fungal secondary metabolism remains highly sensitive following combinatorial stress. The outcome impacts the research towards optimizing fungal oil profiles for biomass and nutrition. Future investigations on fungal stress tolerance mechanisms need to address these environmental factors throughout the experimental design
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