105 research outputs found

    Widespread expression of erythropoietin receptor in brain and its induction by injury

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    Erythropoietin (EPO) exerts potent neuroprotective, neuroregenerative and procognitive functions. However, unequivocal demonstration of erythropoietin receptor (EPOR) expression in brain cells has remained difficult since previously available anti-EPOR antibodies (EPOR-AB) were unspecific. We report here a new, highly specific, polyclonal rabbit EPOR-AB directed against different epitopes in the cytoplasmic tail of human and murine EPOR and its characterization by mass spectrometric analysis of immuno-precipitated endogenous EPOR, Western blotting, immunostaining and flow cytometry. Among others, we applied genetic strategies including overexpression, Lentivirus-mediated conditional knockout of EpoR and tagged proteins, both on cultured cells and tissue sections, as well as intracortical implantation of EPOR-transduced cells to verify specificity. We show examples of EPOR expression in neurons, oligodendroglia, astrocytes and microglia. Employing this new EPOR-AB with double-labeling strategies, we demonstrate membrane expression of EPOR as well as its localization in intracellular compartments such as the Golgi apparatus. Moreover, we show injury-induced expression of EPOR. In mice, a stereotactically applied stab wound to the motor cortex leads to distinct EpoR expression by reactive GFAP-expressing cells in the lesion vicinity. In a patient suffering from epilepsy, neurons and oligodendrocytes of the hippocampus strongly express EPOR. To conclude, this new analytical tool will allow neuroscientists to pinpoint EPOR expression in cells of the nervous system and to better understand its role in healthy conditions, including brain development, as well as under pathological circumstances, such as upregulation upon distress and injury

    ISO-SWS calibration and the accurate modelling of cool-star atmospheres - IV. G9 to M2 stars

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    presented. The 2.38 -- 4.08 micron wavelength-range of band 1 of ISO-SWS (Short-Wavelength Spectrometers on board of the Infrared Space Observatory) in which many different molecules -- with their own dependence on each of the stellar parameters -- are absorbing, enables us to estimate the effective temperature, the gravity, the microturbulence, the metallicity, the CNO-abundances, the 12C/13C-ratio and the angular diameter from the ISO-SWS data. Using the Hipparcos' parallax, the radius, luminosity and gravity-inferred mass are derived. The stellar parameters obtained are in good agreement with other published values, though also some discrepancies with values deduced by other authors are noted. For a few stars (Delta Dra, Xi Dra, Alpha Tuc, H Sco and Alpha Cet) some parameters -- e.g. the CNO-abundances -- are derived for the first time. By examining the correspondence between different ISO-SWS observations of the same object and between the ISO-SWS data and the corresponding synthetic spectrum, it is shown that the relative accuracy of ISO-SWS in band 1 (2.38 -- 4.0 micron) is better than 2% for these high-flux sources. The high level of correspondence between observations and theoretical predictions, together with a confrontation of the estimated Teff(ISO) value with Teff-values derived from colours -- which demonstrates the consistency between V-K, BC(K), Teff and the angular diameter derived from optical or IR data -- proves that both the used MARCS models to derive the stellar quantities and the flux calibration of the ISO-SWS detectors have reached a high level of reliability.Comment: 19 pages, 15 figures; Astronomy and Astrophysics, in press; preprints can be obtained by contacting [email protected] or via WWW on http://www.ster.kuleuven.ac.be/~leen or via anonymous ftp on ftp://ftp.ster.kuleuven.ac.be/dist/leen/latex/h3318 Appendix electronically available (26 pages, 22 figures

    Cotton in the new millennium: advances, economics, perceptions and problems

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    Cotton is the most significant natural fibre and has been a preferred choice of the textile industry and consumers since the industrial revolution began. The share of man-made fibres, both regenerated and synthetic fibres, has grown considerably in recent times but cotton production has also been on the rise and accounts for about half of the fibres used for apparel and textile goods. To cotton’s advantage, the premium attached to the presence of cotton fibre and the general positive consumer perception is well established, however, compared to commodity man-made fibres and high performance fibres, cotton has limitations in terms of its mechanical properties but can help to overcome moisture management issues that arise with performance apparel during active wear. This issue of Textile Progress aims to: i. Report on advances in cotton cultivation and processing as well as improvements to conventional cotton cultivation and ginning. The processing of cotton in the textile industry from fibre to finished fabric, cotton and its blends, and their applications in technical textiles are also covered. ii. Explore the economic impact of cotton in different parts of the world including an overview of global cotton trade. iii. Examine the environmental perception of cotton fibre and efforts in organic and genetically-modified (GM) cotton production. The topic of naturally-coloured cotton, post-consumer waste is covered and the environmental impacts of cotton cultivation and processing are discussed. Hazardous effects of cultivation, such as the extensive use of pesticides, insecticides and irrigation with fresh water, and consequences of the use of GM cotton and cotton fibres in general on the climate are summarised and the effects of cotton processing on workers are addressed. The potential hazards during cotton cultivation, processing and use are also included. iv. Examine how the properties of cotton textiles can be enhanced, for example, by improving wrinkle recovery and reducing the flammability of cotton fibre

    A High Accuracy Defect-Correction Multigrid Method for the Steady Incompressible Navier-Stokes Equations

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    The solution of large sets of equations is required when discrete methods are used to solve fluid flow and heat transfer problems. Although the cost of the solution is often a drawback when the number of equations in the set becomes large, higher order numerical methods can be employed in the discretization of differential equations to decrease the number of equations without losing accuracy. For example, using a fourth-order difference scheme instead of a second-order one would reduce the number of equations by approximately half while preserving the same accuracy. In a recent paper, Gupta has developed a fourth-order compact method for the numerical solution of Navier-Stokes equations. In this paper we propose a defect-correction form of the high order approximations using multigrid techniques. We also derive a fourth-order approximation to the boundary conditions to be consistent with the fourth-order discretization of the underlying differential equations. The convergence analysis will be discussed for the parameterized form of a general second-order correction difference scheme which includes a fourth-order scheme as a special case
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