4,544 research outputs found
Clinical and magnetic resonance imaging characteristics of thoracolumbar intervertenral disk extrusions and protrusions in large breed dogs
Clinical and magnetic resonance imaging characteristics of thoracolumbar intervertenral disk extrusions and protrusions in large breed dogs
It has recently been shown that the fat-derived hormone adiponectin has the ability to decrease hyperglycemia and to reverse insulin resistance. However, bacterially produced full-length adiponectin is functionally inactive. Here, we show that endogenous adiponectin secreted by adipocytes is post-translationally modified into eight different isoforms, as shown by two-dimensional gel electrophoresis. Carbohydrate detection revealed that six of the adiponectin isoforms are glycosylated. The glycosylation sites were mapped to several lysines (residues 68, 71, 80, and 104) located in the collagenous domain of adiponectin, each having the surrounding motif of GXKGE(D). These four lysines were found to be hydroxylated and subsequently glycosylated. The glycosides attached to each of these four hydroxylated lysines are possibly glucosylgalactosyl groups. Functional analysis revealed that full-length adiponectin produced by mammalian cells is much more potent than bacterially generated adiponectin in enhancing the ability of subphysiological concentrations of insulin to inhibit gluconeogenesis in primary rat hepatocytes, whereas this insulin-sensitizing ability was significantly attenuated when the four glycosylated lysines were substituted with arginines. These results indicate that full-length adiponectin produced by mammalian cells is functionally active as an insulin sensitizer and that hydroxylation and glycosylation of the four lysines in the collagenous domain might contribute to this activity.link_to_subscribed_fulltex
The Circumnuclear Ring of Ionized Gas in NGC3593
We present the results of narrow-band Halpha+NII imaging of the early-type
spiral NGC3593 in combination with a study of the flux radial profiles of the
NII (lambda: 654.80, 658.34 nm), Halpha, and SII (lambda: 671.65, 673.08 nm)
emission lines along its major axis. The galaxy is known to contain two
counterrotating stellar discs of different size and luminosity. We find that
the Halpha emission mainly derives from a small central region of 57 arcsec x
25 arcsec. It consists of a filamentary pattern with a central ring. This has a
diameter of about 17 arcsec (~ 0.6/h kpc) and it contributes about half of the
total Halpha flux. The ring is interpreted as the result of the interaction
between the acquired retrograde gas which later formed the smaller
counterrotating stellar disc and the pre-existing prograde gas of the galaxy.Comment: Accepted for pubblication in Astronomy and Astrophysics; one latex
file (corsini.tex), and 2 encapsulated postscript figures
(corsini_fig1.ps,corsini_fig2.ps). To be compiled with aa.cls latex2e macro
style (pslatex option): 6 pages after latex compilatio
Evolution and excitation conditions of outflows in high-mass star-forming regions
Theoretical models suggest that massive stars form via disk-mediated
accretion, with bipolar outflows playing a fundamental role. A recent study
toward massive molecular outflows has revealed a decrease of the SiO line
intensity as the object evolves. The present study aims at characterizing the
variation of the molecular outflow properties with time, and at studying the
SiO excitation conditions in outflows associated with massive YSOs. We used the
IRAM30m telescope to map 14 massive star-forming regions in the SiO(2-1),
SiO(5-4) and HCO+(1-0) outflow lines, and in several dense gas and hot core
tracers. Hi-GAL data was used to improve the spectral energy distributions and
the L/M ratio, which is believed to be a good indicator of the evolutionary
stage of the YSO. We detect SiO and HCO+ outflow emission in all the sources,
and bipolar structures in six of them. The outflow parameters are similar to
those found toward other massive YSOs. We find an increase of the HCO+ outflow
energetics as the object evolve, and a decrease of the SiO abundance with time,
from 10^(-8) to 10^(-9). The SiO(5-4) to (2-1) line ratio is found to be low at
the ambient gas velocity, and increases as we move to high velocities,
indicating that the excitation conditions of the SiO change with the velocity
of the gas (with larger densities and/or temperatures for the high-velocity gas
component). The properties of the SiO and HCO+ outflow emission suggest a
scenario in which SiO is largely enhanced in the first evolutionary stages,
probably due to strong shocks produced by the protostellar jet. As the object
evolves, the power of the jet would decrease and so does the SiO abundance.
During this process, however, the material surrounding the protostar would have
been been swept up by the jet, and the outflow activity, traced by entrained
molecular material (HCO+), would increase with time.Comment: 31 pages, 10 figures and 5 tables (plus 2 figures and 3 tables in the
appendix). Accepted for publication in A&A. [Abstract modified to fit the
arXiv requirements.
Physical properties of high-mass clumps in different stages of evolution
(Abridged) Aims. To investigate the first stages of the process of high-mass
star formation, we selected a sample of massive clumps previously observed with
the SEST at 1.2 mm and with the ATNF ATCA at 1.3 cm. We want to characterize
the physical conditions in such sources, and test whether their properties
depend on the evolutionary stage of the clump.
Methods. With ATCA we observed the selected sources in the NH3(1,1) and (2,2)
transitions and in the 22 GHz H2O maser line. Ammonia lines are a good
temperature probe that allow us to accurately determine the mass and the
column-, volume-, and surface densities of the clumps. We also collected all
data available to construct the spectral energy distribution of the individual
clumps and to determine if star formation is already occurring, through
observations of its most common signposts, thus putting constraints on the
evolutionary stage of the source. We fitted the spectral energy distribution
between 1.2 mm and 70 microns with a modified black body to derive the dust
temperature and independently determine the mass.
Results. The clumps are cold (T~10-30 K), massive (M~10^2-10^3 Mo), and dense
(n(H2)>~10^5 cm^-3) and they have high column densities (N(H2)~10^23 cm^-2).
All clumps appear to be potentially able to form high-mass stars. The most
massive clumps appear to be gravitationally unstable, if the only sources of
support against collapse are turbulence and thermal pressure, which possibly
indicates that the magnetic field is important in stabilizing them.
Conclusions. After investigating how the average properties depend on the
evolutionary phase of the source, we find that the temperature and central
density progressively increase with time. Sources likely hosting a ZAMS star
show a steeper radial dependence of the volume density and tend to be more
compact than starless clumps.Comment: Published in A&A, Vol. 556, A1
Partnership for the Physical Activity Kit (PAK) Staying on the Active Path in Native Communities.
Presented at: 2011 New Mexico Public Health Association Conference; April 27-28; Albuquerque, NM.https://digitalrepository.unm.edu/prc-posters-presentations/1062/thumbnail.jp
Track healthy choices – partnership for the Physical Activity Kit (PAK) Staying on the Active Path in Native Communities – a Lifespan Approach.
Presented at: 4th Annual Southern Obesity Summit; September 12-14; Atlanta, GA.https://digitalrepository.unm.edu/prc-posters-presentations/1063/thumbnail.jp
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