440 research outputs found
Outcome of Patients With Hypertrophic Cardiomyopathy and a Normal Electrocardiogram
ObjectivesThis study sought to clarify the frequency, clinical phenotype, and prognosis of those patients with hypertrophic cardiomyopathy (HCM) who present with a normal electrocardiogram (ECG).BackgroundHypertrophic cardiomyopathy is the most common cause of sudden death in young people. Screening advocates have recommended a 12-lead ECG for the early detection of HCM in athletes, yet the clinical outcomes of those presenting with a normal ECG remains to be fully delineated.MethodsBaseline characteristic and echocardiographic data were collected on all patients with HCM who initially presented to our institution with a diagnostic echocardiogram but a normal ECG. Follow-up was obtained and compared with the prognosis of HCM patients who presented with abnormal ECGs.ResultsWe compared 135 HCM patients with a normal ECG with 2,350 HCM patients with an abnormal ECG. The latter group was more likely to have worse symptoms, have higher gradients, and a greater degree of septal wall thickness than the patients with a normal ECG. Severe obstructive symptoms requiring surgical myectomy and implantation of an implantable cardioverter-defibrillator were more common in patients with abnormal ECGs. Cardiac survival was significantly better in the group with a normal ECG at presentation—none of these patients had a cardiac death at follow-up.ConclusionsAlmost 6% of patients presenting with demonstrable echocardiographic evidence of HCM had a normal ECG at the time of diagnosis. This subset of patients with normal ECG-HCM appears to exhibit a less severe phenotype with better cardiovascular outcomes
GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates
In this study, we report synthesis of large area (> 2 cm^2) crack-free GaInP/GaAs double junction solar cells on 50 mm diameter Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer techniques. Defect removal from the template film and film surface prior to epitaxial growth was found to be critical to achievement of high open circuit voltage and efficiency. Cells grown on templates prepared with chemical mechanical polishing in addition a wet chemical etch show comparable performance to control devices grown on bulk Ge substrates. Current-voltage (I–V) data under AM 1.5 illumination indicate that the short circuit current is comparable in templated and control cells, but the open circuit voltage is slightly lower (2.08V vs. 2.16V). Spectral response measurements indicate a drop in open circuit voltage due to a slight lowering of the top GaInP cell band gap. The drop in band gap is due to a difference in the indium composition in the two samples caused by the different miscut (9° vs. 6°) of the two kinds of substrates
Massage for Children Undergoing Hematopoietic Cell Transplantation: A Qualitative Report
Background. No in-depth qualitative research exists about the effects of therapeutic massage with children hospitalized to undergo hematopoietic cell transplantation (HCT). The objective of this study is to describe parent caregivers' experience of the effects of massage/acupressure for their children undergoing HCT. Methods. We conducted a qualitative analysis of open-ended interviews with 15 parents of children in the intervention arm of a massage/acupressure trial. Children received both practitioner and parent-provided massage/acupressure. Results. Parents reported that their child experienced relief from pain and nausea, relaxation, and greater ease falling asleep. They also reported increased caregiver competence and closeness with their child as a result of learning and performing massage/acupressure. Parents supported a semistandardized massage protocol. Conclusion. Massage/acupressure may support symptom relief and promote relaxation and sleep among pediatric HCT patients if administered with attention to individual patients' needs and hospital routines and may relieve stress among parents, improve caregiver competence, and enhance the sense of connection between parent and child
Diverse antiviral IgG effector activities are predicted by unique biophysical antibody features
Background: The critical role of antibody Fc-mediated effector functions in immune defense has been widely reported in various viral infections. These effector functions confer cellular responses through engagement with innate immune cells. The precise mechanism(s) by which immunoglobulin G (IgG) Fc domain and cognate receptors may afford protection are poorly understood, however, in the context of HIV/SHIV infections. Many different in vitro assays have been developed and utilized to measure effector functions, but the extent to which these assays capture distinct antibody activities has not been fully elucidated. Results: In this study, six Fc-mediated effector function assays and two biophysical antibody profiling assays were performed on a common set of samples from HIV-1 infected and vaccinated subjects. Biophysical antibody profiles supported robust prediction of diverse IgG effector functions across distinct Fc-mediated effector function assays. While a number of assays showed correlated activities, supervised machine learning models indicated unique antibody features as primary contributing factors to the associated effector functions. Additional experiments established the mechanistic relevance of relationships discovered using this unbiased approach. Conclusions: In sum, this study provides better resolution on the diversity and complexity of effector function assays, offering a clearer perspective into this family of antibody mechanisms of action to inform future HIV-1 treatment and vaccination strategies
GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates
Large area, crack-free GaInP/GaAs double junction solar cells were grown by metal organic chemical vapor deposition on Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer. Photovoltaic performance of these devices was comparable to those grown on bulk epi-ready Ge, demonstrating the feasibility of alternative substrates fabricated via wafer bonding and layer transfer for growth of active devices on lattice mismatched substrates
SpeX Spectroscopy of Unresolved Very Low-Mass Binaries. I. Identification of Seventeen Candidate Binaries Straddling the L Dwarf/T Dwarf Transition
We report the identification of 17 candidate brown dwarf binaries whose
components straddle the L dwarf/T dwarf transition. These sources were culled
from a large near-infrared spectral sample of L and T dwarfs observed with the
Infrared Telescope Facility SpeX spectrograph. Candidates were selected on the
basis of spectral ratios which segregate known (resolved) L dwarf/T dwarf pairs
from presumably single sources. Composite templates, constructed by combining
13581 pairs of absolute flux-calibrated spectra, are shown to provide
statistically superior fits to the spectra of our seventeen candidates as
compared to single templates. Ten of these candidates appear to have secondary
components that are significantly brighter than their primaries over the
1.0-1.3 micron band, indicative of rapid condensate depletion at the L dwarf/T
dwarf transition. Our results support prior indications of enhanced
multiplicity amongst early-type T dwarfs; 53+/-7% of the T0-T4 dwarfs in our
spectral sample are found to be either resolved or unresolved (candidate)
pairs, although this is consistent with an intrinsic (volume complete) brown
dwarf binary fraction of only 15%. If verified, this sample of spectral
binaries more than doubles the number of known L dwarf/T dwarf transition
pairs, enabling a broader exploration of this poorly-understood phase of brown
dwarf atmospheric evolution.Comment: 65 pages (11pt manuscript format), 68 figures, accepted for
publication to ApJ; spectral data can be accessed at
http://www.browndwarfs.org/spexpris
The Brown Dwarf Kinematics Project (BDKP) I. Proper Motions and Tangential Velocities for a Large Sample of Late-type M, L and T Dwarfs
We report proper motion measurements for 427 late-type M, L and T dwarfs, 332
of which have been measured for the first time. Combining these new proper
motions with previously published measurements yields a sample of 841 M7-T8
dwarfs. We combined parallax measurements or calculated spectrophotometric
distances and computed tangential velocities for the entire sample. We find
that kinematics for the full and volume-limited 20 pc samples are consistent
with those expected for the Galactic thin disk, with no significant differences
between late-type M, L, and T dwarfs. Applying an age-velocity relation we
conclude that the average kinematic age of the 20 pc sample of ultracool dwarfs
is older than recent kinematic estimates and more consistent with age results
calculated with population synthesis models. There is a statistically distinct
population of high tangential velocity sources whose kinematics suggest an even
older population of ultracool dwarfs belonging to either the Galactic thick
disk or halo. We isolate subsets of the entire sample, including low
surface-gravity dwarfs, unusually blue L dwarfs, and photometric outliers in
J-Ks color and investigate their kinematics. We find that the spectroscopically
distinct class of unusually blue L dwarfs has kinematics clearly consistent
with old age, implying that high surface-gravity and/or low metallicity may be
relevant to their spectral properties. The low surface-gravity dwarfs are
kinematically younger than the overall population, and the kinematics of the
red and blue ultracool dwarfs suggest ages that are younger and older than the
full sample, respectively. We also present a reduced proper motion diagram at
2MASS Ks for the entire population and find that a limit of H_Ks > 18 excludes
M dwarfs from the L and T dwarf population regardless of near-infrared color.Comment: Accepted for publication in the Astronomical Journal, 21 pages text,
12 tables, 12 figure
WISEP J061135.13-041024.0 AB: A J-band Flux Reversal Binary at the L/T Transition
Christopher R. Gelino, et al, 'WISEP J061135.13−041024.0 AB: A J-BAND FLUX REVERSAL BINARY AT THE L/T TRANSITION', The Astronomical Journal, vol. 148 (6), July 2014, doi: http://dx.doi.org/10.1088/0004-6256/148/1/6.We present Keck II laser guide star adaptive optics observations of the brown dwarf WISEP J061135.13−041024.0 showing it is a binary with a component separation of 0. 4. This system is one of the six known resolved binaries in which the magnitude differences between the components show a reversal in sign between the Y/J band and the H/K bands. Deconvolution of the composite spectrum results in a best-fit binary solution with L9 and T1.5 components. We also present a preliminary parallax placing the system at a distance of 21.2 ± 1.3 pc. Using the distance and resolved magnitudes we are able to place WISEP J061135.13−041024.0 AB on a color–absolute magnitude diagram, showing that this system contributes to the well-known “J-band bump” and the components’ properties appear similar to other late-type L and early-type T dwarfs. Fitting our data to a set of cloudy atmosphere models suggests the system has an age >1 Gyr with WISE 0611−0410 A having an effective temperature (Teff) of 1275–1325 K and mass of 64–65 MJup, and WISE 0611−0410 B having Teff = 1075–1115 K and mass 40–65 MJup.Peer reviewe
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