2,710 research outputs found
Gottron's Papules Exhibit Dermal Accumulation of CD44 Variant 7 (CD44v7) and Its Binding Partner Osteopontin: A Unique Molecular Signature
The accumulated mucin in non-Gottron's dermatomyositis (DM) lesions is primarily chondroitin-4-sulfate (C4S), which is immunomodulatory in vitro. Gottron's papules are a particularly resistant manifestation of DM that often persist after other lesions have resolved with therapy. We examined non-Gottron's DM lesions and Gottron's papule skin biopsies for C4S, CD44 variant 7 (CD44v7), a chondroitin sulfate-binding isoform causally implicated in autoimmunity, and osteopontin (OPN), a CD44v7 ligand implicated in chronic inflammation. Gottron's papule dermis contained more C4S and CD44v7 than non-Gottron's lesions. Normal skin showed less CD44v7 over joints relative to Gottron's lesions. All DM dermis had increased OPN compared with healthy skin. Mechanically stretching cultured fibroblasts for 6hours induced CD44v7 mRNA and protein, whereas IFN-Îł treatment induced OPN mRNA and protein. OPN alone did not induce CD44v7, but stretching dermal fibroblasts in the presence of OPN increased human acute monocytic leukemia cell line (THP-1) monocyte binding, which is blunted by anti-CD44v7 blocking antibody. C4S, CD44v7, and OPN are three molecules uniquely present in Gottron's papules that contribute to inflammation individually and in association with one another. We propose that stretch-induced CD44v7 over joints, in concert with dysregulated OPN levels in the skin of DM patients, increases local inflammatory cell recruitment and contributes to the pathogenesis and resistance of Gottron's papules
Variable Intrinsic Absorption in Mrk 279
We examine the variability in the intrinsic absorption in the Seyfert 1
galaxy Mrk 279 using three epochs of observations from the Far Ultraviolet
Spectroscopic Explorer (FUSE) and two epochs of observations with the Space
Telescope Imaging Spectrograph on the Hubble Space Telescope. Rather than
finding simple photoionization responses of the absorbing gas to changes in the
underlying continuum, the observed changes in the absorption profiles can be
understood more clearly if the effective covering fraction of the gas in all
emission components, continuum and broad and intermediate velocity width
emission lines, is accounted for. While we do not uniquely solve for all of
these separate covering fractions and the ionic column densities using the
spectral data, we examine the parameter space using previously well-constrained
solutions for continuum and single emission component covering fractions.
Assuming full coverage of the continuum, we find that of the two velocity
components of the Mrk 279 absorption most likely associated with its outflow,
one likely has zero coverage of the intermediate line region while the other
does not. For each component, however, the broad line region is more fully
covered than the intermediate line region. Changes in the O VI column densities
are unconstrained due to saturation, but we show that small changes in the
nonsaturated C IV and N V column densities are consistent with the outflow gas
having zero or partial covering of the intermediate line region and an
ionization parameter changing from ~0.01 to ~0.1 from 2002 to 2003 as the UV
continuum flux increased by a factor of ~8. The absence of a change in the C
III absorbing column density is attributed to this species arising outside the
Mrk 279 outflow.Comment: 36 pages, 18 figures, accepted to Ap
Dust Emission and Dynamics
When viewed from Earth, most of what we observe of a comet is dust. The
influence of solar radiation pressure on the trajectories of dust particles
depends on their cross-section to mass ratio. Hence solar radiation pressure
acts like a mass spectrometer inside a cometary tail. The appearances of
cometary dust tails have long been studied to obtain information on the dust
properties, such as characteristic particle size and initial velocity when
entering the tail. Over the past two decades, several spacecraft missions to
comets have enabled us to study the dust activity of their targets at much
greater resolution than is possible with a telescope on Earth or in near-Earth
space, and added detail to the results obtained by the spacecraft visiting
comet 1P/Halley in 1986. We now know that the dynamics of dust in the inner
cometary coma is complex and includes a significant fraction of particles that
will eventually fall back to the surface. The filamented structure of the
near-surface coma is thought to result from a combination of topographic
focussing of the gas flow, inhomogeneous distribution of activity across the
surface, and projection effects. It is possible that some
larger-than-centimetre debris contains ice when lifted from the surface, which
can affect its motion. Open questions remain regarding the microphysics of the
process that leads to the detachment and lifting of dust from the surface, the
evolution of the dust while travelling away from the nucleus, and the extent to
which information on the nucleus activity can be retrieved from remote
observations of the outer coma and tail.Comment: Chapter in press for the book Comets III, edited by K. Meech and M.
Combi, University of Arizona Pres
Interdisciplinary Collaboration to ensure the well-being of Deaf and Hard of Hearing Students with Complex Needs
Compared to their hearing counterparts, students who are deaf or hard of hearing face unique challenges as they transition from high school to post high school activities. Students who have co-occurring physical, behavioral health, intellectual or autism related challenges may be at higher risk of destabilization in placement or service access when they are no longer eligible for special education services. In this exploratory study, we aim to begin to quantify how transition coordinators and schools that serve deaf or hard of hearing students collaborate with behavioral health care providers, social service, or developmental disability providers when children they serve age out of educationally funded supportive services. We will also begin to analyze what barriers school personnel face as they aim to promote engagement with behavioral health and developmental disability services for the children and families that they have been serving in the educational system
Whole Genome Analysis of the Red-Crowned Crane Provides Insight into Avian Longevity
The red-crowned crane (Grus japonensis) is an endangered, large-bodied crane native to East Asia. It is a traditional symbol of longevity and its long lifespan has been confirmed both in captivity and in the wild. Lifespan in birds is known to be positively correlated with body size and negatively correlated with metabolic rate, though the genetic mechanisms for the red-crowned crane's long lifespan have not previously been investigated. Using whole genome sequencing and comparative evolutionary analyses against the grey-crowned crane and other avian genomes, including the long-lived common ostrich, we identified red-crowned crane candidate genes with known associations with longevity. Among these are positively selected genes in metabolism and immunity pathways (NDUFA5, NDUFA8, NUDT12, SOD3, CTH, RPA1, PHAX, HNMT, HS2ST1, PPCDC, PSTK CD8B, GP9, IL-9R, and PTPRC). Our analyses provide genetic evidence for low metabolic rate and longevity, accompanied by possible convergent adaptation signatures among distantly related large and long-lived birds. Finally, we identified low genetic diversity in the red-crowned crane, consistent with its listing as an endangered species, and this genome should provide a useful genetic resource for future conservation studies of this rare and iconic species
Intrinsic Absorption in the Spectrum of NGC 7469: Simultaneous Chandra, FUSE, and STIS Observations
We present simultaneous X-ray, far-ultraviolet, and near-ultraviolet spectra
of the Seyfert 1 galaxy NGC 7469 obtained with the Chandra X-Ray Observatory,
the Far Ultraviolet Spectroscopic Explorer, and the Space Telescope Imaging
Spectrograph on the Hubble Space Telescope. Previous non-simultaneous
observations of this galaxy found two distinct UV absorption components, at
-560 and -1900 km/s, with the former as the likely counterpart of the X-ray
absorber. We confirm these two absorption components in our new UV
observations, in which we detect prominent O VI, Ly alpha, N V, and C IV
absorption. In our Chandra spectrum we detect O VIII emission, but no
significant O VIII or O VII absorption. We also detect a prominent Fe K alpha
emission line in the Chandra spectrum, as well as absorption due to
hydrogen-like and helium-like neon, magnesium, and silicon at velocities
consistent with the -560 km/s UV absorber. The FUSE and STIS data reveal that
the H I and C IV column densities in this UV- and X-ray- absorbing component
have increased over time, as the UV continuum flux decreased. We use measured H
I, N V, C IV, and O VI column densities to model the photoionization state of
both absorbers self-consistently. We confirm the general physical picture of
the outflow in which the low velocity component is a highly ionized, high
density absorber with a total column density of 10^20 cm^-2, located near the
broad emission line region, although due to measurable columns of N V and C IV,
we assign it a somewhat smaller ionization parameter than found previously,
U~1. The high velocity UV component is of lower density, log N=18.6, and likely
resides farther from the central engine as we find its ionization parameter to
be U=0.08.Comment: Minor correction to abstract; STScI eprint #1683; 50 pages, incl. 19
figures, 4 tables; Accepted to Ap
Quasars and the Big Blue Bump
We investigate the ultraviolet-to-optical spectral energy distributions
(SEDs) of 17 active galactic nuclei (AGNs) using quasi-simultaneous
spectrophotometry spanning 900-9000 Angstrom (rest frame). We employ data from
the Far Ultraviolet Spectroscopic Explorer (FUSE), the Hubble Space Telescope
(HST), and the 2.1-meter telescope at Kitt Peak National Observatory (KPNO).
Taking advantage of the short-wavelength coverage, we are able to study the
so-called "big blue bump," the region where the energy output peaks, in detail.
Most objects exhibit a spectral break around 1100 Angstrom. Although this
result is formally associated with large uncertainty for some objects, there is
strong evidence in the data that the far-ultraviolet spectral region is below
the extrapolation of the near-ultraviolet-optical slope, indicating a spectral
break around 1100 Angstrom. We compare the behavior of our sample to those of
non-LTE thin-disk models covering a range in black-hole mass, Eddington ratio,
disk inclination, and other parameters. The distribution of ultraviolet-optical
spectral indices redward of the break, and far-ultraviolet indices shortward of
the break, are in rough agreement with the models. However, we do not see a
correlation between the far-ultraviolet spectral index and the black hole mass,
as seen in some accretion disk models. We argue that the observed spectral
break is intrinsic to AGNs, although intrinsic reddening as well as
Comptonization can strongly affect the far-ultraviolet spectral index. We make
our data available online in digital format.Comment: 32 pages (10pt), 12 figures. Accepted for publication in Ap
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