626 research outputs found
West Nile Virus Antibody Prevalence in Wild Mammals, Southern Wisconsin
Twenty percent prevalence of West Nile virus antibody was found in free-ranging medium-sized Wisconsin mammals. No significant differences were noted in antibody prevalence with regard to sex, age, month of collection, or species. Our results suggest a similar route of infection in these mammals
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Human immunodeficiency virus type 1 mutants resistant to nonnucleoside inhibitors of reverse transcriptase arise in tissue culture
We have recently described a nonnucleoside compound that specifically inhibits the reverse transcriptase of human immunodeficiency virus type 1 (HIV-1), the causative agent of AIDS. This compound, nevirapine (BI-RG-587), interacts with highly conserved tyrosine residues at positions 181 and 188 in the reverse transcriptase to inhibit the recombinant enzyme and virus replication in cell culture with 50% inhibitory concentrations in the 40 nM range. HIV-1 variants resistant to nevirapine emerged with passage in cell culture in the presence of drug. This resistant phenotype was stable with continued passage in the absence of drug. These mutants had a substitution of cysteine for the tyrosine at position 181. Introduction of this mutation into the recombinant enzyme increased the inhibitory concentration of nevirapine 100-fold. Substitution of cysteine for tyrosine at residue 181 into the wild-type viral genome conferred a similar reduction in susceptibility to nevirapine. Mutants were also resistant to a tetrahydroimidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-one and -thione derivative and two 6-phenylthiouracil derivatives but retained their sensitivity to the other reverse transcriptase inhibitors, 3'-azido-3'-deoxythymidine and foscarnet
Light scattering from ultracold atomic gases in optical lattices at finite temperature
We study light scattering from atoms in optical lattices at finite
temperature. We examine the light scattered by fermions in the noninteracting
regime and by bosons in the superfluid and Mott insulating regimes. We extend
previous theoretical studies to include the full band structure of the optical
lattice. We find that light scattering that excites atoms out of the lowest
band leads to an increase in light scattering away from the classical
diffraction peaks and is largely temperature independent. This additional light
scattering leads to lower efficiency of temperature measurements based on
photon counting.Comment: 10 pages, 6 figure
Together, yet still not equal? Sex integration in equestrian sport
Sex segregation is a core organising principle of most modern sports and is a key element in the marginalisation and subordination of girls and women in sport and beyond. In this article I explore the only Olympic-level sport which is not organised around sex segregation â equestrian sport â in order to consider the implications of sex integration for female participants. I draw on a study conducted on elite riders that found that although sex integration in equestrian sport does not lead to female participants being excluded from high-level competition, men continue to perform disproportionately well. This suggests that although sex integration may be an important step towards breaking down gender hierarchies in sport, without accompanying wider changes in gender norms and expectations, sex integration alone will not be enough to achieve greater gender equality in equestrian sport
Incidence of symptomatic venous thromboembolism in oncologic patients undergoing lower-extremity endoprosthetic arthroplasty
Valvuloarterial Impedence, Strain, Exercise, and AS
Background - In asymptomatic patients with severe aortic stenosis and preserved left ventricular ejection fraction, we sought to assess the incremental prognostic value of resting valvuloarterial impedence (Zva) and left ventricular global longitudinal strain (LV-GLS) to treadmill stress echocardiography.
Methods and Results - We studied 504 such patients (66±12 years, 78% men, 32% with coronary artery disease who underwent treadmill stress echocardiography between 2001 and 2012. Clinical and exercise variables (% of age-sex predicted metabolic equivalents [%AGP-METs]) were recorded. Resting Zva ([systolic arterial pressure+mean aortic valve gradient]/[LV-stroke volume index]) and LV-GLS(measured offline using Velocity Vector Imaging, Siemens) were obtained from the baseline resting echocardiogram. Death was the primary outcome. There were no major adverse cardiac events during treadmill stress echocardiography. Indexed aortic valve area, Zva, and LV-GLS were 0.46±0.1 cm2/m2, 4.5±0.9 mm Hg/mL per m2 and -16±4%, respectively; only 50% achieved >100% AGP-METs. Sixty-four percent underwent aortic valve replacement. Death occurred in 164 (33%) patients over 8.9±3.6 years (2 within 30 days of aortic valve replacement). On multivariable Cox survival analysis, higher Society of Thoracic Surgeons score (hazard ratio or HR 1.06), lower % AGP-METS (HR 1.16), higher Zva (HR 1.25) and lower LV-GLS (HR 1.12) were associated with higher longer-term mortality, while aortic valve replacement (HR 0.45) was associated with improved survival (all P<0.01). Sequential addition of ZVa and LV-GLS to clinical model (Society of Thoracic Surgeons score and %AGP-METs) increased the c-statistic from 0.65 to 0.69 and 0.75, respectively, both P<0.001); findings were similar in the subgroup of patients who underwent aortic valve replacement.
Conclusions - In asymptomatic patients with severe aortic stenosis undergoing treadmill stress echocardiography, LV-GLS and ZVa offer incremental prognostic value
Ligand and Receptor Dynamics Contribute to the Mechanism of Graded PPARÎł Agonism
SummaryLigand binding to proteins is not a static process, but rather involves a number of complex dynamic transitions. A flexible ligand can change conformation upon binding its target. The conformation and dynamics of a protein can change to facilitate ligand binding. The conformation of the ligand, however, is generally presumed to have one primary binding mode, shifting the protein conformational ensemble from one state to another. We report solution nuclear magnetic resonance (NMR) studies that reveal peroxisome proliferator-activated receptor Îł (PPARÎł) modulators can sample multiple binding modes manifesting in multiple receptor conformations in slow conformational exchange. Our NMR, hydrogen/deuterium exchange and docking studies reveal that ligand-induced receptor stabilization and binding mode occupancy correlate with the graded agonist response of the ligand. Our results suggest that ligand and receptor dynamics affect the graded transcriptional output of PPARÎł modulators
A Bright Submillimeter Source in the Bullet Cluster (1E0657--56) Field Detected with BLAST
We present the 250, 350, and 500 micron detection of bright submillimeter
emission in the direction of the Bullet Cluster measured by the Balloon-borne
Large Aperture Submillimeter Telescope (BLAST). The 500 micron centroid is
coincident with an AzTEC 1.1 mm point-source detection at a position close to
the peak lensing magnification produced by the cluster. However, the 250 micron
and 350 micron centroids are elongated and shifted toward the south with a
differential shift between bands that cannot be explained by pointing
uncertainties. We therefore conclude that the BLAST detection is likely
contaminated by emission from foreground galaxies associated with the Bullet
Cluster. The submillimeter redshift estimate based on 250-1100 micron
photometry at the position of the AzTEC source is z_phot = 2.9 (+0.6 -0.3),
consistent with the infrared color redshift estimation of the most likely IRAC
counterpart. These flux densities indicate an apparent far-infrared luminosity
of L_FIR = 2E13 Lsun. When the amplification due to the gravitational lensing
of the cluster is removed, the intrinsic far-infrared luminosity of the source
is found to be L_FIR <= 10^12 Lsun, consistent with typical luminous infrared
galaxies.Comment: Accepted for publication in the Astrophysical Journal. Maps are
available at http://blastexperiment.info
Over half of the far-infrared background light comes from galaxies at z >= 1.2
Submillimetre surveys during the past decade have discovered a population of
luminous, high-redshift, dusty starburst galaxies. In the redshift range 1 <= z
<= 4, these massive submillimetre galaxies go through a phase characterized by
optically obscured star formation at rates several hundred times that in the
local Universe. Half of the starlight from this highly energetic process is
absorbed and thermally re-radiated by clouds of dust at temperatures near 30 K
with spectral energy distributions peaking at 100 microns in the rest frame. At
1 <= z <= 4, the peak is redshifted to wavelengths between 200 and 500 microns.
The cumulative effect of these galaxies is to yield extragalactic optical and
far-infrared backgrounds with approximately equal energy densities. Since the
initial detection of the far-infrared background (FIRB), higher-resolution
experiments have sought to decompose this integrated radiation into the
contributions from individual galaxies. Here we report the results of an
extragalactic survey at 250, 350 and 500 microns. Combining our results at 500
microns with those at 24 microns, we determine that all of the FIRB comes from
individual galaxies, with galaxies at z >= 1.2 accounting for 70 per cent of
it. As expected, at the longest wavelengths the signal is dominated by
ultraluminous galaxies at z > 1.Comment: Accepted to Nature. Maps available at http://blastexperiment.info
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