159 research outputs found
Bhlhe40 controls cytokine production by T cells and is essential for pathogenicity in autoimmune neuroinflammation
T(H)1 and T(H)17 cells mediate neuroinflammation in experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Pathogenic T(H) cells in EAE must produce the pro-inflammatory cytokine granulocyte-macrophage colony stimulating factor (GM-CSF). T(H) cell pathogenicity in EAE is also regulated by cell-intrinsic production of the immunosuppressive cytokine interleukin 10 (IL-10). Here, we demonstrate that mice deficient for the basic helix-loop-helix (bHLH) transcription factor Bhlhe40 (Bhlhe40(−/−)) are resistant to the induction of EAE. Bhlhe40 is required in vivo in a T cell-intrinsic manner, where it positively regulates the production of GM-CSF and negatively regulates the production of IL-10. In vitro, GM-CSF secretion is selectively abrogated in polarized Bhlhe40(−/−) T(H)1 and T(H)17 cells, and these cells show increased production of IL-10. Blockade of IL-10 receptor in Bhlhe40(−/−) mice renders them susceptible to EAE. These findings identify Bhlhe40 as a critical regulator of autoreactive T cell pathogenicity
The N2K Consortium. II. A Transiting Hot Saturn Around HD 149026 With a Large Dense Core
Doppler measurements from Subaru and Keck have revealed radial velocity
variations in the V=8.15, G0IV star HD 149026 consistent with a Saturn-Mass
planet in a 2.8766 day orbit. Photometric observations at Fairborn Observatory
have detected three complete transit events with depths of 0.003 mag at the
predicted times of conjunction. HD 149026 is now the second brightest star with
a transiting extrasolar planet. The mass of the star, based on interpolation of
stellar evolutionary models, is 1.3 +/- 0.1 solar masses; together with the
Doppler amplitude, K=43.3 m s^-1, we derive a planet mass Msin(i)=0.36 Mjup,
and orbital radius of 0.042 AU. HD 149026 is chromospherically inactive and
metal-rich with spectroscopically derived [Fe/H]=+0.36, Teff=6147 K, log g=4.26
and vsin(i)=6.0 km s^-1. Based on Teff and the stellar luminosity of 2.72 Lsun,
we derive a stellar radius of 1.45 Rsun. Modeling of the three photometric
transits provides an orbital inclination of 85.3 +/- 1.0 degrees and (including
the uncertainty in the stellar radius) a planet radius of 0.725 +/- 0.05 Rjup.
Models for this planet mass and radius suggest the presence of a ~67 Mearth
core composed of elements heavier than hydrogen and helium. This substantial
planet core would be difficult to construct by gravitational instability.Comment: 25 pages, 5 figures, accepted by the Astrophysical Journa
Absolute properties of the low-mass eclipsing binary CM Draconis
Spectroscopic and eclipsing binary systems offer the best means for
determining accurate physical properties of stars, including their masses and
radii. The data available for low-mass stars have yielded firm evidence that
stellar structure models predict smaller radii and higher effective
temperatures than observed, but the number of systems with detailed analyses is
still small. In this paper we present a complete reanalysis of one of such
eclipsing systems, CM Dra, composed of two dM4.5 stars. New and existing light
curves as well as a radial velocity curve are modeled to measure the physical
properties of both components. The masses and radii determined for the
components of CM Dra are M1=0.2310+/-0.0009 Msun, M2=0.2141+/-0.0010 Msun,
R1=0.2534+/-0.0019 Rsun, and R2=0.2396+/-0.0015 Rsun. With relative
uncertainties well below the 1% level, these values constitute the most
accurate properties to date for fully convective stars. This makes CM Dra a
valuable benchmark for testing theoretical models. In comparing our
measurements with theory, we confirm the discrepancies reported previously for
other low-mass eclipsing binaries. These discrepancies seem likely to be due to
the effects of magnetic activity. We find that the orbit of this system is
slightly eccentric, and we have made use of eclipse timings spanning three
decades to infer the apsidal motion and other related properties.Comment: 19 pages, 9 figures. Accepted for publication in Ap
Late-Type Near-Contact Eclipsing Binary [HH97] FS Aur-79
The secondary photometric standard star #79 for the FS Aur field (Henden &
Honeycutt 1997) designated as [HH97] FS Aur-79 (GSC 1874 399) is a short period
(0.2508 days) eclipsing binary whose light curve is a combination of the
Lyr and BY Dra type variables. High signal-to-noise multi-color
photometry were obtained using the USNO 1-m telescope. These light curves show
asymmetry at quadrature phases (O'Connell effect), which can be modeled with
the presence of star spots. A low resolution spectrum obtained with the 3.5-m
WIYN telescope at orbital phase 0.76 is consistent with a spectral type of dK7e
and dM3e. A radial velocity curve for the primary star was constructed using
twenty-four high resolution spectra from the 9.2 m HET. Spectra show H-alpha
and H-beta in emission confirming chromospheric activity and possibly the
presence of circumstellar material. Binary star models that simultaneously fit
the U, B, V, R and RV curves are those with a primary star of mass 0.59+-0.02
Msun, temperature 4100+-25 K, mean radius of 0.67 Rsun, just filling its Roche
lobe and a secondary star of mass 0.31+-0.09 Msun, temperature 3425+-25 K, mean
radius of 0.48 Rsun, just within its Roche lobe. An inclination angle of 83+-2
degrees with a center of mass separation of 1.62 Rsun is also derived. Star
spots, expected for a rotation period of less than a day, had to be included in
the modeling to fit the O'Connell effect
The LMC eclipsing binary HV 2274: fundamental properties and comparison with evolutionary models
We are carrying out an international, multi-wavelength program to determine
the fundamental properties and independent distance estimates of selected
eclipsing binaries in the LMC and SMC. Eclipsing binaries with well-defined
double-line radial velocity curves and light curves provide valuable
information on orbital and physical properties of their component stars. The
study of stars in the LMC and SMC where the metal abundances are significantly
lower than solar provides an important opportunity to test stellar atmosphere,
interior and evolution models, and opacities. For the first time, we can also
measure direct M-L relations for stars outside our Galaxy. In this paper we
concentrate on the determination of the orbital and physical properties of HV
2274 from analyses of light curves and new radial velocity curves formed from
HST/GHRS observations. From UV/optical spectrophotometry of HV 2274 obtained
with HST/FOS, the temperatures and the metallicity of the stars were found, as
well as the interstellar extinction of the system. The values of mass, absolute
radius, and effective temperature, for the primary and secondary stars are:
12.2(7) Mo, 9.9(2) Ro, 23000(180) K, and 11.4(7) Mo, 9.0(2) Ro, 23110(180) K,
respectively. The age of the system (17(2) Myr), helium abundance (Y=0.26(3))
and a lower limit of the convective core overshooting parameter of 0.2 were
obtained from fitting the stellar data with evolution models. The apsidal
motion analysis corroborates that some amount of convective overshooting
(0.2-0.5) is needed.Comment: 39 pages, 9 figures, accepted for publication in Ap
The VOICES typology of curatorial decisions in narrative collections of the lived experiences of mental health service use, recovery or madness: qualitative study
Background: Collections of lived experience narratives are increasingly used in health research and medical practice. However there is limited research concerning the decision-making processes in curating narrative collections, and of the work that curators do as they build and publish collections.
Objective: The objectives of this study were to develop a typology of curatorial decisions involved in curating narrative collections presenting lived experiences of mental health service use, recovery or madness, and to document approaches selected by curators in relation to identified curatorial decision.
Methods: A preliminary typology was developed by synthesising the results of a systematic review with insights gained through an iterative consultation with an experienced curator of multiple recovery narrative collections. The preliminary typology informed the topic guide for semi-structured interviews with a maximum variation sample of 30 curators from 7 different countries. All participants had experience of curating narrative collections of the lived experiences of mental health service use, recovery or madness. Thematic analysis through constant comparison was conducted by a multidisciplinary team.
Results: The final typology identified six themes, giving the acronym VOICES: Values and motivations, Organisation, Inclusion and exclusion, Control and collaboration, Ethics and legal, Safety and wellbeing. 26 sub-themes relating to curation decisions were identified.
Conclusions: The VOICES typology identifies key decisions to consider when curating narrative collections about the lived experiences of mental health service use, recovery or madness. The VOICES typology might be used as a theoretical basis for a good practice resource, to support curators in their efforts to balance the challenges and sometimes conflicting imperatives involved in collecting, organising and sharing narratives. Future research might seek to document the usage of such a tool by curators, and hence examine how best to use VOICES to support decision making
Safety and efficacy of oral DMSA therapy for children with autism spectrum disorders: Part A - Medical results
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