Photochemical radical initiation is a powerful tool for studying radical initiation and transport in biology. Ribonucleotide reductases (RNRs), which catalyze the conversion of nucleotides to ...deoxynucleotides in all organisms, are an exemplar of radical mediated transformations in biology. Class Ia RNRs are composed of two subunits: α2 and β2. As a method to initiate radical formation photochemically within β2, a single surface-exposed cysteine of the β2 subunit of Escherichia coli Class Ia RNR has been labeled (98%) with a photooxidant (Re = tricarbonyl(1,10-phenanthroline)(methylpyridyl)rhenium(I)). The labeling was achieved by incubation of S355C-β2 with the 4-(bromomethyl)pyridyl derivative of Re to yield the labeled species, Re-S355C-β2. Steady-state and time-resolved emission experiments reveal that the metal-to-ligand charge transfer (MLCT) excited-state 3Re * is not significantly perturbed after bioconjugation and is available as a phototrigger of tyrosine radical at position 356 in the β2 subunit; transient absorption spectroscopy reveals that the radical lives for microseconds. The work described herein provides a platform for photochemical radical initiation and study of proton-coupled electron transfer (PCET) in the β2 subunit of RNR, from which radical initiation and transport for this enzyme originates.
We report cosmic microwave background (CMB) power-spectrum measurements from the first 100 deg{sup 2} field observed by the South Pole Telescope (SPT) at 150 and 220 GHz. On angular scales where the ...primary CMB anisotropy is dominant, l {approx}< 3000, the SPT power spectrum is consistent with the standard {Lambda}CDM cosmology. On smaller scales, we see strong evidence for a point-source contribution, consistent with a population of dusty, star-forming galaxies. After we mask bright point sources, anisotropy power on angular scales of 3000 < l < 9500 is detected with a signal-to-noise ratio {approx}>50 at both frequencies. We combine the 150 and 220 GHz data to remove the majority of the point-source power and use the point-source-subtracted spectrum to detect Sunyaev-Zel'dovich (SZ) power at 2.6{sigma}. At l = 3000, the SZ power in the subtracted bandpowers is 4.2 {+-} 1.5 {mu}K{sup 2}, which is significantly lower than the power predicted by a fiducial model using WMAP5 cosmological parameters. This discrepancy may suggest that contemporary galaxy cluster models overestimate the thermal pressure of intracluster gas. Alternatively, this result can be interpreted as evidence for lower values of {sigma}{sub 8}. When combined with an estimate of the kinetic SZ contribution, the measured SZ amplitude shifts {sigma}{sub 8} from the primary CMB anisotropy derived constraint of 0.794 {+-} 0.028 down to 0.773 {+-} 0.025. The uncertainty in the constraint on {sigma}{sub 8} from this analysis is dominated by uncertainties in the theoretical modeling required to predict the amplitude of the SZ power spectrum for a given set of cosmological parameters.
We use a temperature map of the cosmic microwave background (CMB) obtained using the South Pole Telescope at 150 GHz to construct a map of the gravitational convergence to z ~ 1100, revealing the ...fluctuations in the projected mass density. This map shows individual features that are significant at the ~4sigma level, providing the first image of CMB lensing convergence. We cross-correlate this map with Herschel/SPIRE maps covering 90 deg super(2) at wavelengths of 500, 350, and 250 mu m. We show that these submillimeter (submm) wavelength maps are strongly correlated with the lensing convergence map, with detection significances in each of the three submm bands ranging from 6.7sigma to 8.8sigma. We fit the measurement of the cross power spectrum assuming a simple constant bias model and infer bias factors of b = 1.3-1.8, with a statistical uncertainty of 15%, depending on the assumed model for the redshift distribution of the dusty galaxies that are contributing to the Herschel/SPIRE maps.
Aims: To characterise patients with birdshot chorioretinopathy (BCR) clinically and electrophysiologically in order to monitor changes in retinal function before and after treatment with ...corticosteroids and/or immunosuppression. Methods: 18 patients with BCR were characterised clinically and electrophysiologically. Serial studies were performed on 14 patients in order to monitor changes in retinal function before and after treatment with corticosteroids and/or immunosuppression. Results: Most patients presented with characteristic subretinal pale spots, were HLA-A29 positive, and had diverse signs of ocular inflammation. Various electrophysiological abnormalities were present. Moderately severe bilateral pattern electroretinogram (PERG) abnormalities at presentation were common, reflecting macular dysfunction. Cone mediated 30 Hz flicker electroretinograms (ERGs) were consistently delayed before treatment, and were the most sensitive parameter of retinal dysfunction. Scotopic maximal ERG responses were abnormal in 13 patients; 10 had an electronegative maximal ERG or a reduced b:a ratio in one or both eyes. Single flash photopic ERGs were less often and less severely affected. Photopic ON and OFF ERG responses often revealed predominant ON response b-wave abnormalities with relative OFF response preservation. ERGs improved in treated cases, sometimes preceding clinical signs of recovery. Pattern ERG improvements occurred, possibly reflecting the resolution of macular oedema. Conclusions: The ERG data confirm that BCR frequently affects inner retinal function of cone and rod systems. Clinical features were not reliable indicators of functional deterioration or recovery. Objective electrophysiological assessment of retinal function demonstrated improvement following treatment and provides a reliable method of monitoring treatment efficacy, enabling management decisions to be taken with greater confidence and allowing early initiation or modification of treatment.
The electrophysiological findings in optic nerve and primary ganglion cell dysfunction are reviewed. The value of the pattern reversal visual-evoked potential (VEP) in the diagnosis of optic nerve ...disease, and the pattern appearance VEP in the demonstration of the intracranial misrouting associated with albinism, are discussed. The pattern electroretinogram (PERG) is used in the direct assessment of ganglion cell function. The use of PERG or multifocal electroretinography (mfERG), to enable the distinction between VEP delay due to optic nerve disease and that due to macular dysfunction, is described.
In the past decade, our understanding of galaxy evolution has been revolutionized by the discovery that luminous, dusty starburst galaxies were 1,000 times more abundant in the early Universe than at ...present. It has, however, been difficult to measure the complete redshift distribution of these objects, especially at the highest redshifts (z > 4). Here we report a redshift survey at a wavelength of three millimetres, targeting carbon monoxide line emission from the star-forming molecular gas in the direction of extraordinarily bright millimetre-wave-selected sources. High-resolution imaging demonstrates that these sources are strongly gravitationally lensed by foreground galaxies. We detect spectral lines in 23 out of 26 sources and multiple lines in 12 of those 23 sources, from which we obtain robust, unambiguous redshifts. At least 10 of the sources are found to lie at z > 4, indicating that the fraction of dusty starburst galaxies at high redshifts is greater than previously thought. Models of lens geometries in the sample indicate that the background objects are ultra-luminous infrared galaxies, powered by extreme bursts of star formation.
We report constraints on cosmological parameters from the angular power spectrum of a cosmic microwave background (CMB) gravitational lensing potential map created using temperature data from 2500 ...deg2 of South Pole Telescope (SPT) data supplemented with data from Planck in the same sky region, with the statistical power in the combined map primarily from the SPT data. We fit the lensing power spectrum to a model including cold dark matter and a cosmological constant ( ), and to models with single-parameter extensions to . We find constraints that are comparable to and consistent with those found using the full-sky Planck CMB lensing data, e.g., = 0.598 0.024 from the lensing data alone with weak priors placed on other parameters. Combining with primary CMB data, we explore single-parameter extensions to . We find or < 0.70 eV at 95% confidence, in good agreement with results including the lensing potential as measured by Planck. We include two parameters that scale the effect of lensing on the CMB: , which scales the lensing power spectrum in both the lens reconstruction power and in the smearing of the acoustic peaks, and , which scales only the amplitude of the lensing reconstruction power spectrum. We find × = 1.01 0.08 for the lensing map made from combined SPT and Planck data, indicating that the amount of lensing is in excellent agreement with expectations from the observed CMB angular power spectrum when not including the information from smearing of the acoustic peaks.
We use data from the first 100 deg{sup 2} field observed by the South Pole Telescope (SPT) in 2008 to measure the angular power spectrum of temperature anisotropies contributed by the background of ...dusty star-forming galaxies (DSFGs) at millimeter wavelengths. From the auto- and cross-correlation of 150 and 220 GHz SPT maps, we significantly detect both Poisson distributed and, for the first time at millimeter wavelengths, clustered components of power from a background of DSFGs. The spectral indices of the Poisson and clustered components are found to be {alpha}-bar{sup P}{sub 150-220}=3.86{+-}0.23 and {alpha} {sup C}{sub 150-220} = 3.8 {+-} 1.3, implying a steep scaling of the dust emissivity index {beta} {approx} 2. The Poisson and clustered power detected in SPT, BLAST (at 600, 860, and 1200 GHz), and Spitzer (1900 GHz) data can be understood in the context of a simple model in which all galaxies have the same graybody spectrum with dust emissivity index of {beta} = 2 and dust temperature T{sub d} = 34 K. In this model, half of the 150 GHz background light comes from redshifts greater than 3.2. We also use the SPT data to place an upper limit on the amplitude of the kinetic Sunyaev-Zel'dovich power spectrum at l = 3000 of 13 {mu}K{sup 2} at 95% confidence.
ABSTRACT
We present Sunyaev–Zel'dovich (SZ) measurements of 15 massive X-ray-selected galaxy clusters obtained with the South Pole Telescope (SPT). The SZ cluster signals are measured at 150 GHz, and ...concurrent 220 GHz data are used to reduce astrophysical contamination. Radial profiles are computed using a technique that takes into account the effects of the beams and filtering. In several clusters, significant SZ decrements are detected out to a substantial fraction of the virial radius. The profiles are fit to the β-model and to a generalized Navarro–Frenk–White (NFW) pressure profile, and are scaled and stacked to probe their average behavior. We find model parameters that are consistent with previous studies: β = 0.86 and
r
core
/
r
500
= 0.20 for the β-model, and (α
n
, β
n
, γ
n
,
c
500
) = (1.0, 5.5, 0.5, 1.0) for the generalized NFW model. Both models fit the SPT data comparably well, and both are consistent with the average SZ profile out to beyond
r
500
. The integrated Compton-
y
parameter
Y
SZ
is computed for each cluster using both model-dependent and model-independent techniques, and the results are compared to X-ray estimates of cluster parameters. We find that
Y
SZ
scales with
Y
X
and gas mass with low scatter. Since these observables have been found to scale with total mass, our results point to a tight mass–observable relation for the SPT cluster survey.
Abstract
Introduction
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide and is associated with mortality rates as high as 30%. Patients with TBI are at high risk for ...secondary injury and need to be transported to definitive care expeditiously. However, the physiologic effects of aeromedical evacuation are not well understood and may compound these risks. Combat TBI patients may benefit from delayed aeromedical evacuation. The goal of this study was to evaluate the impact of transport timing out of theater via Critical Care Air Transport Teams (CCATT) to a higher level facility on the clinical outcomes of combat casualties with TBI.
Materials and Methods
We performed a retrospective review of patients with TBI who were evacuated out of theater by CCATT from January 2007 to May 2014. Data abstractors collected flight information, vital signs, procedures, in-flight assessments, and outcomes. Time to transport was defined as the time from injury to CCATT evacuation out of combat theater. We calculated descriptive statistics and constructed regression models to determine the association between time to transport and clinical outcomes. This study was approved by the U.S. Air Force 59th Medical Wing Institutional Review Board.
Results
We analyzed the records of 438 patients evacuated out of theater via CCATT and categorized them into three groups: patients who were transported in one day or less (n = 165), two days (n = 163), and three or more days (n = 110). We used logistic regression models to compare outcomes among patients who were evacuated in two days or three or more days to those who were transported within one day while adjusting for demographics, injury severity, and injury type. Patients who were evacuated in two days or three or more days had 50% lower odds of being discharged on a ventilator and were twice as likely to return to duty or be discharged home than those who were evacuated within one day. Additionally, patients transported in three or more days were 70% less likely to be ventilated at discharge with a GCS of 8 or lower and had 30% lower odds of mortality than those transported within one day.
Conclusions
In patients with moderate to severe TBI, a delay in aeromedical evacuation out of the combat theater was associated with improved mortality rates and a higher likelihood of discharge to home and return to duty dispositions. This study is correlational in nature and focused on CCATT transports from Role III to Role IV facilities; as such, care must be taken in interpreting our findings and future studies are needed to establish a causal link between delayed evacuation and improved discharge disposition. Our study suggests that delaying aeromedical evacuation of TBI patients when feasible may confer benefit.
PDF
