10,194 research outputs found

    Expression of the insulin-like growth factor-II/mannose-6-phosphate receptor in multiple human tissues during fetal life and early infancy

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    The insulin like growth factor-II/mannose-6-phosphate (IGF-II/M6P) receptor has been detected in many cells and tissues. In the rat, there is a dramatic developmental regulation of IGF-II/M6P receptor expression, the receptor being high in fetal and neonatal tissues and declining thereafter. We have systematically studied the expression of the human IGF-II/M6P receptor protein in tissues from 10 human fetuses and infants (age 23 weeks gestation to 24 months postnatal). We have asked 1) whether there is differential expression among different organs, and 2) whether or not the human IGF-II/M6P receptor is developmentally regulated from 23 weeks gestation to 24 months postnatal. Protein was extracted from human tissues using a buffer containing 2% sodium dodecyl sulfate and 2% Triton X-100. Aliquots of the protein extracts were analyzed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis and immunoblotting using an anti-IGF- II/M6P receptor antiserum (no. 66416) and 125I-protein A or an immunoperoxidase stain. IGF-II/M6P receptor immunoreactivity was detected in all tissues studied with the highest amount of receptor being expressed in heart, thymus, and kidney and the lowest receptor content being measured in brain and muscle. The receptor content in ovary, testis, lung, and spleen was intermediate. The apparent molecular weight of the IGF-II/M6P receptor (220,000 kilos without reduction of disulfide bonds) varied among the different tissues: in brain the receptor was of lower molecular weight than in other organs. Immunoquantitation experiments employing 125I-protein A and protein extracts from human kidney at different ages revealed a small, albeit not significant, difference of the receptor content between fetal and postnatal tissues: as in other species, larger amounts of receptor seemed to be present in fetal than in postnatal organs. In addition, no significant difference of the receptor content between human fetal liver and early postnatal liver was measured employing 125I-protein A- immunoquantitation in three fetal and five postnatal liver tissue samples. The distribution of IGF-binding protein (IGEBP) species, another abundant and major class of IGF binding principles, was also measured in human fetal and early postnatal lung, liver, kidney, muscle, and brain using Western ligand blotting with 125I-IGF-II: as with IGF-II/M6P receptor immunoreactivity there was differential expression of the different classes of IGFBPs in the various organs

    Monte Carlo direct simulation technique user's manual

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    User manual for Monte Carlo direct simulation techniqu

    Mott scattering of polarized electrons in a strong laser field

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    We present analytical and numerical results of the relativistic calculation of the transition matrix element SfiS_{fi} and differential cross section for Mott scattering of initially polarized Dirac particles (electrons) in the presence of strong laser field with linear polarization. We use exact Dirac-Volkov wave functions to describe the dressed electrons and the collision process is treated in the first Born approximation. The influence of the laser field on the degree of polarization of the scattered electron is reported.Comment: 12 pages, 11 figures, Revte

    Detection of Far-Infrared Water Vapor, Hydroxyl, and Carbon Monoxide Emissions from the Supernova Remnant 3C 391

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    We report the detection of shock-excited far-infrared emission of H2O, OH, and CO from the supernova remnant 3C 391, using the ISO Long-Wavelength Spectrometer. This is the first detection of thermal H2O and OH emission from a supernova remnant. For two other remnants, W~28 and W~44, CO emission was detected but OH was only detected in absorption. The observed H2O and OH emission lines arise from levels within ~400 K of the ground state, consistent with collisional excitation in warm, dense gas created after the passage of the shock front through the dense clumps in the pre-shock cloud. The post-shock gas we observe has a density ~2x10^5 cm^{-3} and temperature 100-1000 K, and the relative abundances of CO:OH:H2O in the emitting region are 100:1:7 for a temperature of 200 K. The presence of a significant column of warm H2O suggests that the chemistry has been significantly changed by the shock. The existence of significant column densities of both OH and H2O, which is at odds with models for non-dissociative shocks into dense gas, could be due to photodissociation of H2O or a mix of fast and slow shocks through regions with different pre-shock density.Comment: AASTeX manuscript and 4 postscript figure

    Two-finger selection theory in the Saffman-Taylor problem

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    We find that solvability theory selects a set of stationary solutions of the Saffman-Taylor problem with coexistence of two \it unequal \rm fingers advancing with the same velocity but with different relative widths λ1\lambda_1 and λ2\lambda_2 and different tip positions. For vanishingly small dimensionless surface tension d0d_0, an infinite discrete set of values of the total filling fraction λ=λ1+λ2\lambda = \lambda_1 + \lambda_2 and of the relative individual finger width p=λ1/λ2p=\lambda_1/\lambda_2 are selected out of a two-parameter continuous degeneracy. They scale as λ−1/2∌d02/3\lambda-1/2 \sim d_0^{2/3} and ∣p−1/2âˆŁâˆŒd01/3|p-1/2| \sim d_0^{1/3}. The selected values of λ\lambda differ from those of the single finger case. Explicit approximate expressions for both spectra are given.Comment: 4 pages, 3 figure

    Microscopic Selection of Fluid Fingering Pattern

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    We study the issue of the selection of viscous fingering patterns in the limit of small surface tension. Through detailed simulations of anisotropic fingering, we demonstrate conclusively that no selection independent of the small-scale cutoff (macroscopic selection) occurs in this system. Rather, the small-scale cutoff completely controls the pattern, even on short time scales, in accord with the theory of microscopic solvability. We demonstrate that ordered patterns are dynamically selected only for not too small surface tensions. For extremely small surface tensions, the system exhibits chaotic behavior and no regular pattern is realized.Comment: 6 pages, 5 figure

    Mid-Infrared Emission from E+A Galaxies in the Coma Cluster

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    We have used ISO to observe at 12ÎŒ\mum seven E+A galaxies plus an additional emission line galaxy, all in the Coma cluster. E+A galaxies lacking narrow emission lines have 2.2ÎŒ\mum to 12ÎŒ\mum flux density ratios or limits similar to old stellar populations (typical of early-type galaxies). Only galaxies with emission lines have enhanced 12ÎŒ\mum flux density. Excess 12ÎŒ\mum emission is therefore correlated with the presence of on-going star formation or an active galactic nucleus (AGN). By comparing the current star formation rates with previous rates estimated from the Balmer absorption features, we divide the galaxies into two groups: those for which star formation has declined significantly following a dramatic peak ∌\sim 1 Gyr ago; and those with a significant level of ongoing star formation or/and an AGN. There is no strong difference in the spatial distribution on the sky between these two groups. However, the first group has systemic velocities above the mean cluster value and the second group below that value. This suggests that the two groups differ kinematically. Based on surveys of the Coma cluster in the radio, the IRAS sources, and galaxies detected in Hα\alpha emission, we sum the far infrared luminosity function of galaxies in the cluster. We find that star formation in late type galaxies is probably the dominant component of the Coma cluster far infrared luminosity. The presence of significant emission from intracluster dust is not yet firmly established. The member galaxies also account for most of the far infrared output from nearby rich clusters in general.Comment: AAS Latex, accepted for publication in Ap
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