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Barriers to Pediatric Sickle Cell Disease Guideline Recommendations.
National guidelines recommend that providers counsel all patients with sickle cell anemia about hydroxyurea (HU) therapy and screen children with sickle cell anemia annually for the risk of stroke with transcranial Doppler (TCD). We surveyed a national convenience sample of sickle cell disease clinicians to assess factors associated with low adherence. Adherence was 46% for TCD screening. Low adherence was associated with a lack of outcome expectancy (eg, a belief that there would be poor patient follow-up to TCD testing; P < .05). Adherence was 72% for HU counseling. Practice barriers (eg, lack of support staff or time) and a lack of agreement with HU recommendations were associated with low adherence (P < .05). This study demonstrates that different types of strategies are needed to improve TCD screening (to address follow-up and access to testing) versus HU counseling (to address physician agreement and practice barriers)
A case series of premenstrual disorders presenting to the UK's National Female Hormone Clinic
Aims and method
We aimed to describe the clinical characteristics of female patients presenting with premenstrual disorders to a tertiary service in the UK. We conducted a retrospective case-note review of referrals to the National Female Hormone Clinic from April 2014 to August 2020. Based on clinical assessment, we determined whether the patient met criteria for premenstrual dysphoric disorder or premenstrual exacerbation of an underlying psychiatric disorder.
Results
Of 146 patients seen in clinic for premenstrual disorders, an ICD-10 psychiatric diagnosis was made in 130 (89.0%); a minority 16 (11.0%) did not have a psychiatric diagnosis. Following assessment, 94 patients (64.4%) met criteria for premenstrual dysphoric disorder and 67 (45.6%) had exacerbation of a psychiatric disorder.
Clinical implications
Patients presenting to this specialist service had complex psychiatric comorbidity; almost half presented with exacerbation of a psychiatric disorder
Measurement of an AGN Central Mass on Centiparsec Scales: Results of Long-Term Optical Monitoring of Arp 102B
The optical spectrum of the broad-line radio galaxy Arp 102B has been
monitored for more than thirteen years to investigate the nature of the source
of its broad, double-peaked hydrogen Balmer emission lines. The shape of the
lines varied subtly; there was an interval during which the variation in the
ratio of the fluxes of the two peaks appeared to be sinusoidal, with a period
of 2.16 years and an amplitude of about 16% of the average value. The variable
part of the broad H-alpha line is well fit by a model in which a region of
excess emission (a quiescent ``hot spot'') within an accretion disk (fitted to
the non-varying portion of the double-peaked line) completes at least two
circular orbits and eventually fades. Fits to spectra from epochs when the hot
spot is not present allow determination of the disk inclination, while fits for
epochs when it is present provide a measurement of the radius of the hot spot's
orbit. From these data and the period of variation, we find that the mass
within the hot spot's orbit is 2.2 +0.2/-0.7 times 10^8 solar masses, within
the range of previous estimates of masses of active galactic nuclei. Because
this mass is determined at a relatively small distance (~1000 AU) from the
central body, it is extremely difficult to explain without assuming that a
supermassive black hole lies within Arp 102B. The lack of any systematic change
in the velocity of the blue peak over time yields a lower limit on the combined
mass of the two bodies in a binary black hole model like that of Gaskell (1983)
of 10^10 solar masses.Comment: 29 pages, including 6 figures; to appear in the Astrophysical Journal
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Practical application of AAPM Report 270 in display quality assurance: A report of Task Group 270
Published in January 2019, AAPM Report 270 provides an update to the recommendations of the AAPM\u27s TG18 report. Report 270 provides new definitions of display types, updated testing patterns, and revised performance standards for the modern, flat-panel displays used as part of medical image acquisition and review. The focus of the AAPM report is on consistent image quality and appearance, and how to establish a quality assurance program to achieve those two goals. This work highlights some of the key takeaways of AAPM Report 270 and makes comparisons with existing recommendations from other references. It also provides guidance for establishing a display quality assurance program for different-sized institutions. Finally, it describes future challenges for display quality assurance and what work remains
High contrast ultrasonic imaging of resin-rich regions in graphite/epoxy composites using entropy
This study compares different approaches for imaging a near-surface resin-rich defect in a thin graphite/epoxy plate using backscattered ultrasound. The specimen was created by cutting a circular hole in the second ply; this region filled with excess resin from the graphite/epoxy sheets during the curing process. Backscat-tered waveforms were acquired using a 4 in. focal length, 5MHz center frequency broadband transducer, scanned on a 100 × 100 grid of points that were 0.03 × 0.03 in. apart. The specimen was scanned with the defect side closest to the transducer. Consequently, the reflection from the resin-rich region cannot be gated from the large front-wall echo. At each point in the grid 256 waveforms were averaged together and subsequently used to produce peak-to-peak, Signal Energy (sum of squared digitized waveform values), as well as entropy images of two different types (a Renyi entropy, and a joint entropy). As the figure shows, all of the entropy images exhibit better border delineation and defect contrast than the either the peak-to-peak or Signal Energy. The best results are obtained using the joint entropy of the backscattered waveforms with a reference function. Two different references are examined. The first is a reflection of the insonifying pulse from a stainless steel reflector. The second is an approximate optimum obtained from an iterative parametric search. The joint entropy images produced using this reference exhibit three times the contrast obtained in previous studies
Entropy vs. Energy Waveform Processing: A Comparison Based on the Heat Equation
Virtually all modern imaging devices collect electromagnetic or acoustic waves and use the energy carried by these waves to determine pixel values to create what is basically an “energy” picture. However, waves also carry “information,” as quantified by some form of entropy, and this may also be used to produce an “information” image. Numerous published studies have demonstrated the advantages of entropy, or “information imaging”, over conventional methods. The most sensitive information measure appears to be the joint entropy of the collected wave and a reference signal. The sensitivity of repeated experimental observations of a slowly-changing quantity may be defined as the mean variation (i.e., observed change) divided by mean variance (i.e., noise). Wiener integration permits computation of the required mean values and variances as solutions to the heat equation, permitting estimation of their relative magnitudes. There always exists a reference, such that joint entropy has larger variation and smaller variance than the corresponding quantities for signal energy, matching observations of several studies. Moreover, a general prescription for finding an “optimal” reference for the joint entropy emerges, which also has been validated in several studies
Early VEGF testing in inflammatory neuropathy avoids POEMS syndrome misdiagnosis and associated costs.
BACKGROUND: Prompt diagnosis and early treatment prevents disability in Polyneuropathy Organomegaly Endocrinopathy Monoclonal-protein and Skin Changes (POEMS) syndrome. Delay in diagnosis is common with 55% of patients initially incorrectly diagnosed with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Patients are often treated with intravenous immunoglobulin which is both expensive and ineffective in the treatment of POEMS. Testing patients with acquired demyelinating neuropathy with serum vascular endothelial growth factor (VEGF) more accurately identifies POEMS syndrome than the current standard of care. Incorporating VEGF testing into screening could prevent misdiagnosis and reduce costs. METHODS: We used observed treatment information for patients in the University College London Hospital's POEMS syndrome database (n=100) and from the National Immunoglobulin Database to estimate costs associated with incorrect CIDP diagnoses across our cohort. We conducted a model-based cost-effectiveness analysis to compare the current diagnostic algorithm with an alternative which includes VEGF testing for all patients with an acquired demyelinating neuropathy. RESULTS: Treatment associated with an incorrect CIDP diagnosis led to total wasted healthcare expenditures of between £808 550 and £1 111 756 across our cohort, with an average cost-per-POEMS-patient misdiagnosed of £14 701 to £20 214. Introducing mandatory VEGF testing for patients with acquired demyelinating neuropathy would lead to annual cost-savings of £107 398 for the National Health Service and could prevent misdiagnosis in 16 cases per annum. CONCLUSIONS: Misdiagnosis in POEMS syndrome results in diagnostic delay, disease progression and significant healthcare costs. Introducing mandatory VEGF testing for patients with acquired demyelinating neuropathy is a cost-effective strategy allowing for early POEMS diagnosis and potentially enabling prompt disease-directed therapy
A Study of the Diverse T Dwarf Population Revealed by WISE
We report the discovery of 87 new T dwarfs uncovered with the Wide-field
Infrared Survey Explorer (WISE) and three brown dwarfs with extremely red
near-infrared colors that exhibit characteristics of both L and T dwarfs. Two
of the new T dwarfs are likely binaries with L7+/-1 primaries and mid-type T
secondaries. In addition, our follow-up program has confirmed 10 previously
identified T dwarfs and four photometrically-selected L and T dwarf candidates
in the literature. This sample, along with the previous WISE discoveries,
triples the number of known brown dwarfs with spectral types later than T5.
Using the WISE All-Sky Source Catalog we present updated color-color and
color-type diagrams for all the WISE-discovered T and Y dwarfs. Near-infrared
spectra of the new discoveries are presented, along with spectral
classifications. To accommodate later T dwarfs we have modified the integrated
flux method of determining spectral indices to instead use the median flux.
Furthermore, a newly defined J-narrow index differentiates the early-type Y
dwarfs from late-type T dwarfs based on the J-band continuum slope. The K/J
indices for this expanded sample show that 32% of late-type T dwarfs have
suppressed K-band flux and are blue relative to the spectral standards, while
only 11% are redder than the standards. Comparison of the Y/J and K/J index to
models suggests diverse atmospheric conditions and supports the possible
re-emergence of clouds after the L/T transition. We also discuss peculiar brown
dwarfs and candidates that were found not to be substellar, including two Young
Stellar Objects and two Active Galactic Nuclei. The coolest WISE-discovered
brown dwarfs are the closest of their type and will remain the only sample of
their kind for many years to come.Comment: Accepted to ApJS on 15 January 2013; 99 pages in preprint format, 30
figures, 12 table
Evidence For A Precessing Accretion Disk in the Nucleus of NGC 1097
We present new spectroscopic observations of the LINER (and now Seyfert 1)
nucleus of NGC 1097, and discuss the evolution of its broad, double-peaked
Balmer lines. When originally discovered in 1991, the red peak of the
double-peaked H-alpha line was stronger than the blue, while by 1994 the
H-alpha profile had become almost symmetric and the integrated line flux had
decreased to half its original value. Our new spectrum, taken in 1996, shows
that the broad, double-peaked lines have returned to almost their original
strengths, the profiles of H-beta and H-alpha are identical to within errors,
and the broad-line emitting region is unreddened. However, the profile of the
Balmer lines is now such that the blue peak is stronger than the red, opposite
to the asymmetry observed in 1991. Various models are considered for the
observed behavior, all assuming that the emission lines originate in an
accretion disk. We present a refined version of the precessing, planar,
elliptical accretion ring model proposed by Storchi-Bergmann et al. and
Eracleous et al. This model provides an acceptable fit to the line profiles. We
also consider the possibility that the line profile evolution results from a
precessing warp in the disk, induced by irradiation from the center, and show
that the range of radii and precession time scales expected in this model are
consistent with the observations. The sudden appearance of the "disk-like"
broad line profiles in NGC 1097 could have resulted from the formation of a new
accretion disk due to, for example, the tidal disruption of a star, or the
illumination of a pre-existing disk by a transient ionizing source at the
center of the disk.Comment: Accepted for publication in the Astrophysical Journal. TeX file with
5 postscript figures embeded using psfig.tex, 13 page
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