656 research outputs found
INTRAOSSEOUS SARCOIDOSIS MIMICKING AS BONE METASTASES ON 18F- FDG PET/CT
A 62-year-old male with known prostate cancer underwent 18F- uorodeoxyglucose positron emission tomography/ computed tomography (18F-FDG PET/CT) scan for suspected osseous metastases after a magnetic resonance imaging of the pelvis, done for chronic low back pain and demonstrated a number of suspicious T1 hypointense/T2 hyperintense lesions in the sacrum, iliac bones and right proximal femur.18F-FDG PET/CT showed abnormal foci of increased tracer uptake in the sacrum, iliac bones and right proximal femur. Core biopsies from the sacrum were performed, showing intertrabecular non-caseating granulomata with surrounding small lymphocytes. Acid-fast bacilli and Gomori methenamine silver stains were negative, consistent with intraosseous sarcoidosis. Key words: 18F- uorodeoxyglucose positron emission tomography/computed tomography, non-caseating granulomata, sarcoidosis
Genetic Subdivision and Variation in Selfing Rates Among Central American Populations of the Mangrove Rivulus, Kryptolebias marmoratus.
We used 32 polymorphic microsatellite loci to investigate how a mixed-mating system affects population genetic structure in Central American populations (N = 243 individuals) of the killifish Kryptolebias marmoratus (mangrove rivulus), 1 of 2 of the world's only known self-fertilizing vertebrates. Results were also compared with previous microsatellite surveys of Floridian populations of this species. For several populations in Belize and Honduras, population structure and genetic differentiation were pronounced and higher than in Florida, even though the opposite trend was expected because populations in the latter region were presumably smaller and highly selfing. The deduced frequency of selfing (s) ranged from s = 0.39-0.99 across geographic locales in Central America. This heterogeneity in selfing rates was in stark contrast to Florida, where s > 0.9. The frequency of outcrossing in a population (t = 1 - s) was tenuously correlated with local frequencies of males, suggesting that males are one of many factors influencing outcrossing. Observed distributions of individual heterozygosity showed good agreement with expected distributions under an equilibrium mixed-mating model, indicating that rates of selfing remained relatively constant over many generations. Overall, our results demonstrate the profound consequences of a mixed-mating system for the genetic architecture of a hermaphroditic vertebrate
VLBI observations of seven BL Lac objects from RGB sample
We present EVN observations of seven BL Lac objects selected from the RGB
sample. To investigate the intrinsic radiation property of BL Lac objects, we
estimated the Doppler factor with the VLA or MERLIN core and the total 408 MHz
luminosity for a sample of 170 BL Lac objects. The intrinsic (comoving)
synchrotron peak frequency was then calculated by using the estimated Doppler
factor. Assuming a Lorentz factor of 5, the viewing angle of jets was
constrained. The high-resolution VLBI images of seven sources all show a
core-jet structure. We estimated the proper motions of three sources with the
VLBI archive data, and find that the apparent speed increases with the distance
of components to the core for all of them. In our BL Lacs sample, the Doppler
factor of LBLs is systematically larger than that of IBLs and HBLs. We find a
significant anti-correlation between the total 408 MHz luminosity and the
intrinsic synchrotron peak frequency. However, the scatter is much larger than
for the blazar sequence. Moreover, we find a significant positive correlation
between the viewing angle and the intrinsic synchrotron peak frequency. The BL
Lac objects show a continuous distribution on the viewing angle. While LBLs
have a smaller viewing angle than that of IBLs and HBLs, IBLs are comparable to
HBLs. We conclude that the intrinsic synchrotron peak frequency is not only
related to the intrinsic radio power (though with a large scatter), but also to
the viewing angle for the present sample.Comment: 22 pages,15figures, published by A&
X-ray Insights into the Nature of Weak Emission-Line Quasars at High Redshift
We present Chandra observations of nine high-redshift quasars (z=2.7-5.9)
discovered by the Sloan Digital Sky Survey with weak or undetectable
high-ionization emission lines in their UV spectra (WLQs). Adding archival
X-ray observations of six additional sources of this class has enabled us to
place the strongest constraints yet on the X-ray properties of this remarkable
class of AGNs. Although our data cannot rule out the possibility that the
emission lines are overwhelmed by a relativistically boosted continuum, as
manifested by BL Lac objects, we find that WLQs are considerably weaker in the
X-ray and radio bands than the majority of BL Lacs found at much lower
redshifts. If WLQs are high-redshift BL Lacs, then it is difficult to explain
the lack of a large parent population of X-ray and radio bright weak-lined
sources at high redshift. We also consider the possibility that WLQs are
quasars with extreme properties, and in particular that the emission lines are
suppressed by high accretion rates. Using joint spectral fitting of the X-ray
spectra of 11 WLQs we find that the mean photon index in the hard X-ray band is
consistent with those observed in typical radio-quiet AGNs with no hint of an
unusually steep hard-X-ray spectrum. This result poses a challenge to the
hypothesis that WLQs have extremely high accretion rates, and we discuss
additional observations required to test this idea.Comment: 13 pages (emulateapj), 7 figures. Accepted for publication in Ap
The technologies of isolation: apocalypse and self in Kurosawa Kiyoshi's Kairo
In this investigation of the Japanese film Kairo, I contemplate how the horrors present in the film relate to the issue of self, by examining a number of interlocking motifs. These include thematic foci on disease and technology which are more intimately and inwardly focused that the film's conclusion first appears to suggest. The true horror here, I argue, is ontological: centred on the self and its divorcing from the exterior world, especially founded in an increased use of and reliance on communicative technologies. I contend that these concerns are manifested in Kairo by presenting the spread of technology as disease-like, infecting the city and the individuals who are isolated and imprisoned by their urban environment. Finally, I investigate the meanings of the apocalypse, expounding how it may be read as hopeful for the future rather than indicative of failure or doom
Using the Multiphase Optimization Strategy (MOST) to optimize an HIV care continuum intervention for vulnerable populations : a study protocol
Abstract: Background. More than half of persons living with HIV (PLWH) in the United States are insufficiently engaged in HIV primary care and not taking antiretroviral therapy (ART), mainly African Americans/Blacks and Hispanics. In the proposed project, a potent and innovative research methodology, the multiphase optimization strategy (MOST), will be employed to develop a highly efficacious, efficient, scalable, and cost-effective intervention to increase engagement along the HIV care continuum. Whereas randomized controlled trials are valuable for evaluating the efficacy of multi-component interventions as a package, they are not designed to evaluate which specific components contribute to efficacy. MOST, a pioneering, engineering-inspired framework, addresses this problem through highly efficient randomized experimentation to assess the performance of individual intervention components and their interactions. We propose to use MOST to engineer an intervention to increase engagement along the HIV care continuum for African American/Black and Hispanic PLWH not well engaged in care and not taking ART. Further, the intervention will be optimized for cost-effectiveness. A similar set of multi-level factors impede both HIV care and ART initiation for African American/Black and Hispanic PLWH, primary among them individual- (e.g., substance use, distrust, fear), social- (e.g., stigma), and structural-level barriers (e.g., difficulties accessing ancillary services). Guided by a multi-level social cognitive theory, the study will evaluate five distinct intervention components (i.e., Motivational Interviewing counseling sessions, pre-adherence preparation, support groups, peer mentorship, and patient navigation), each designed to address a specific barrier to HIV care and ART initiation. These components are well-grounded in the empirical literature and were found acceptable, feasible, and promising with respect to efficacy in a preliminary study. Methods/design. Study aims are: 1) using a highly efficient fractional factorial experimental design, identify which of five intervention components contribute meaningfully to improvement in HIV viral suppression, and secondary outcomes of ART adherence and engagement in HIV primary care; 2) identify mediators and moderators of intervention component efficacy; and 3) using a mathematical modeling approach, build the most cost-effective and efficient intervention package from the efficacious components. A heterogeneous sample of African American/Black and Hispanic PLWH (with respect to age, substance use, and sexual minority status) will be recruited with a proven hybrid sampling method using targeted sampling in community settings and peer recruitment (N=512). Discussion. This is the first study to apply the MOST framework in the field of HIV prevention and treatment. This innovative study will produce an HIV care continuum intervention for the nation's most vulnerable PLWH, optimized for cost-effectiveness, and with exceptional levels of efficacy, efficiency, and scalability
Stability of Satellite Planes in M31 II: Effects of the Dark Subhalo Population
The planar arrangement of nearly half the satellite galaxies of M31 has been
a source of mystery and speculation since it was discovered. With a growing
number of other host galaxies showing these satellite galaxy planes, their
stability and longevity have become central to the debate on whether the
presence of satellite planes are a natural consequence of prevailing
cosmological models, or represent a challenge. Given the dependence of their
stability on host halo shape, we look into how a galaxy plane's dark matter
environment influences its longevity. An increased number of dark matter
subhalos results in increased interactions that hasten the deterioration of an
already-formed plane of satellite galaxies in spherical dark halos. The role of
total dark matter mass fraction held in subhalos in dispersing a plane of
galaxies present non trivial effects on plane longevity as well. But any
misalignments of plane inclines to major axes of flattened dark matter halos
lead to their lifetimes being reduced to < 3 Gyrs. Distributing > 40% of total
dark mass in subhalos in the overall dark matter distribution results in a
plane of satellite galaxies that is prone to change through the 5 Gyr
integration time period.Comment: 11 pages, 9 figures, accepted to MNRAS September 22 201
A Large Sample of BL Lacs from SDSS and FIRST
We present a large sample of 501 radio-selected BL Lac candidates from the
combination of the Sloan Digital Sky Survey (SDSS) Data Release 5 optical
spectroscopy and from the Faint Images of the Radio Sky at Twenty-Centimeters
(FIRST) radio survey; this is one of the largest BL Lac samples yet assembled,
and each object emerges with homogeneous data coverage. Each candidate is
detected in the radio from FIRST and confirmed in SDSS optical spectroscopy to
have: (1) no emission feature with measured rest equivalent width larger than 5
Angstroms; and (2) no measured Ca II H/K depression larger than 40%. We
subdivide our sample into 426 higher confidence candidates and 75 lower
confidence candidates. We argue that contamination from other classes of
objects that formally pass our selection criteria is small, and we identify a
few very rare radio AGN with unusual spectra that are probably related to broad
absorption line quasars. About one-fifth of our sample were known BL Lacs prior
to the SDSS. A preliminary analysis of the sample generally supports the
standard beaming paradigm. While we recover sizable numbers of low-energy and
intermediate-energy cutoff BL Lacs (LBLs and IBLs, respectively), there are
indications of a potential bias toward recovering high-energy cutoff BL Lacs
(HBLs) from SDSS spectroscopy. Such a large sample may eventually provide new
constraints on BL Lac unification models and their potentially peculiar cosmic
evolution; in particular, our sample contains a significant number of higher
redshift objects, a sub-population for which the standard paradigm has yet to
be rigorously constrained.Comment: 16 pages, 13 figures, 6 tables. Accepted for Publication in the
Astronomical Journa
Dyclonine rescues frataxin deficiency in animal models and buccal cells of patients with Friedreich's ataxia.
Inherited deficiency in the mitochondrial protein frataxin (FXN) causes the rare disease Friedreich's ataxia (FA), for which there is no successful treatment. We identified a redox deficiency in FA cells and used this to model the disease. We screened a 1600-compound library to identify existing drugs, which could be of therapeutic benefit. We identified the topical anesthetic dyclonine as protective. Dyclonine increased FXN transcript and FXN protein dose-dependently in FA cells and brains of animal models. Dyclonine also rescued FXN-dependent enzyme deficiencies in the iron-sulfur enzymes, aconitase and succinate dehydrogenase. Dyclonine induces the Nrf2 [nuclear factor (erythroid-derived 2)-like 2] transcription factor, which we show binds an upstream response element in the FXN locus. Additionally, dyclonine also inhibited the activity of histone methyltransferase G9a, known to methylate histone H3K9 to silence FA chromatin. Chronic dosing in a FA mouse model prevented a performance decline in balance beam studies. A human clinical proof-of-concept study was completed in eight FA patients dosed twice daily using a 1% dyclonine rinse for 1 week. Six of the eight patients showed an increase in buccal cell FXN levels, and fold induction was significantly correlated with disease severity. Dyclonine represents a novel therapeutic strategy that can potentially be repurposed for the treatment of FA
- …