Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension Gμ below 10(-8) in some regions of the cosmic string parameter space.

Indoor airborne bacterial communities are influenced by ventilation, occupancy, and outdoor air source

Architects and engineers are beginning to consider a new dimension of indoor air: the structure and composition of airborne microbial communities. A first step in this emerging field is to understand the forces that shape the diversity of bioaerosols across space and time within the built environment. In an effort to elucidate the relative influences of three likely drivers of indoor bioaerosol diversity - variation in outdoor bioaerosols, ventilation strategy, and occupancy load - we conducted an intensive temporal study of indoor airborne bacterial communities in a high-traffic university building with a hybrid HVAC (mechanically and naturally ventilated) system. Indoor air communities closely tracked outdoor air communities, but human-associated bacterial genera were more than twice as abundant in indoor air compared with outdoor air. Ventilation had a demonstrated effect on indoor airborne bacterial community composition; changes in outdoor air communities were detected inside following a time lag associated with differing ventilation strategies relevant to modern building design. Our results indicate that both occupancy patterns and ventilation strategies are important for understanding airborne microbial community dynamics in the built environment.

Measurements of an ablator-gas atomic mix in indirectly driven implosions at the National Ignition Facility

We present the first results from an experimental campaign to measure the atomic ablator-gas mix in the deceleration phase of gas-filled capsule implosions on the National Ignition Facility. Plastic capsules containing CD layers were filled with tritium gas; as the reactants are initially separated, DT fusion yield provides a direct measure of the atomic mix of ablator into the hot spot gas. Capsules were imploded with x rays generated in hohlraums with peak radiation temperatures of ∼294  eV. While the TT fusion reaction probes conditions in the central part (core) of the implosion hot spot, the DT reaction probes a mixed region on the outer part of the hot spot near the ablator-hot-spot interface. Experimental data were used to develop and validate the atomic-mix model used in two-dimensional simulations.

Ferret lung transplant: an orthotopic model of obliterative bronchiolitis

Obliterative bronchiolitis (OB) is the primary cause of late morbidity and mortality following lung transplantation. Current animal models do not reliably develop OB pathology. Given the similarities between ferret and human lung biology, we hypothesized an orthotopic ferret lung allograft would develop OB. Orthotopic left lower lobe transplants were successfully performed in 22 outbred domestic ferrets in the absence of immunosuppression (IS; n = 5) and presence of varying IS protocols (n = 17). CT scans were performed to evaluate the allografts. At intervals between 3-6 months the allografts were examined histologically for evidence of acute/chronic rejection. IS protects allografts from acute rejection and early graft loss. Reduction of IS dosage by 50% allowed development of controlled rejection. Allografts developed infiltrates on CT and classic histologic acute rejection and lymphocytic bronchiolitis. Cycling of IS, to induce repeated episodes of controlled rejection, promoted classic histologic hallmarks of OB including fibrosis-associated occlusion of the bronchiolar airways in all allografts of long-term survivors. In conclusion, we have developed an orthotopic lung transplant model in the ferret with documented long-term functional allograft survival. Allografts develop acute rejection and lymphocytic bronchiolitis, similar to humans. Long-term survivors develop histologic changes in the allografts that are hallmarks of OB.

Charged-particle spectroscopy for diagnosing shock ρR and strength in NIF implosions

The compact Wedge Range Filter (WRF) proton spectrometer was developed for OMEGA and transferred to the National Ignition Facility (NIF) as a National Ignition Campaign diagnostic. The WRF measures the spectrum of protons from D-(3)He reactions in tuning-campaign implosions containing D and (3)He gas; in this work we report on the first proton spectroscopy measurement on the NIF using WRFs. The energy downshift of the 14.7-MeV proton is directly related to the total ρR through the plasma stopping power. Additionally, the shock proton yield is measured, which is a metric of the final merged shock strength.

Neutron spectrometry--an essential tool for diagnosing implosions at the National Ignition Facility (invited)

DT neutron yield (Y(n)), ion temperature (T(i)), and down-scatter ratio (dsr) determined from measured neutron spectra are essential metrics for diagnosing the performance of inertial confinement fusion (ICF) implosions at the National Ignition Facility (NIF). A suite of neutron-time-of-flight (nTOF) spectrometers and a magnetic recoil spectrometer (MRS) have been implemented in different locations around the NIF target chamber, providing good implosion coverage and the complementarity required for reliable measurements of Y(n), T(i), and dsr. From the measured dsr value, an areal density (ρR) is determined through the relationship ρR(tot) (g∕cm(2)) = (20.4 ± 0.6) × dsr(10-12 MeV). The proportionality constant is determined considering implosion geometry, neutron attenuation, and energy range used for the dsr measurement. To ensure high accuracy in the measurements, a series of commissioning experiments using exploding pushers have been used for in situ calibration of the as-built spectrometers, which are now performing to the required accuracy. Recent data obtained with the MRS and nTOFs indicate that the implosion performance of cryogenically layered DT implosions, characterized by the experimental ignition threshold factor (ITFx), which is a function of dsr (or fuel ρR) and Y(n), has improved almost two orders of magnitude since the first shot in September, 2010.

A novel particle time of flight diagnostic for measurements of shock- and compression-bang times in D3He and DT implosions at the NIF

The particle-time-of-flight (pTOF) diagnostic, fielded alongside a wedge range-filter (WRF) proton spectrometer, will provide an absolute timing for the shock-burn weighted ρR measurements that will validate the modeling of implosion dynamics at the National Ignition Facility (NIF). In the first phase of the project, pTOF has recorded accurate bang times in cryogenic DT, DT exploding pusher, and D(3)He implosions using DD or DT neutrons with an accuracy better than ±70 ps. In the second phase of the project, a deflecting magnet will be incorporated into the pTOF design for simultaneous measurements of shock- and compression-bang times in D(3)He-filled surrogate implosions using D(3)He protons and DD-neutrons, respectively.

Measurement of electron temperature of imploded capsules at the National Ignition Facility

The electron and ion temperatures of the imploded core plasma are two of the most important metrics of inertial confinement fusion experiments. We have developed a technique for inferring electron temperatures from the contrast of x-ray images observed through a group of x-ray filters. Generally, the plasma electron temperature exhibits spatial and temporal variations, so time-averaged and time-resolved measurements are expected to yield somewhat different results. By analyzing the intensity of images observed with both a time-integrated detector (imaging plates) and a time-resolved detector (gated micro-channel plate), we found the electron temperature observed from x-ray images to be systematically higher than the ion temperature inferred from fusion neutron spectroscopy.

Measuring the absolute deuterium-tritium neutron yield using the magnetic recoil spectrometer at OMEGA and the NIF

A magnetic recoil spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.

Performance of age-adjusted D-dimer cut-off to rule out pulmonary embolism

BACKGROUND

Age-adjusted D-dimer cut-off has recently been proposed to increase D-dimer usefulness in older patients suspected of pulmonary embolism (PE).

OBJECTIVE

We externally validated this age-adjusted D-dimer cut-off using different D-dimer assays in a multicenter sample of emergency department patients.

METHODS

Secondary analysis of three prospectively collected databases (two European, one American) of patients suspected of having PE. D-dimer performance for ruling out PE was assessed by calculating negative likelihood ratio (nLR) for D-dimer with age-adjusted D-dimer cut-off (< age × 10 in patients over 50 years) and with conventional cut-off (< 500 μg dL(-1)). Test efficiency was assessed by the number needed to test (NNT) to rule out PE in one patient.

RESULTS

Among 4537 patients included, overall PE prevalence was 10.1%. In the overall population, nLR was 0.06 (95% confidence interval, 0.03-0.09) with conventional cut-off and 0.08 (0.05-0.12) with age-adjusted cut-off. Using age-adjusted cut-off, nLR was 0.08, 0.09 and 0.06 for Vidas(®) , Liatest(®) and MDA(®) assays, respectively. Use of age-adjusted cut-off produced a favorable effect on NNT in the elderly; the greatest decrease was observed in patients > 75 years: NTT halved from 8.1 to 3.6. The proportion of patients over 75 years with normal D-dimer was doubled (27.9% vs. 12.3%).

CONCLUSIONS

Our study shows that age-adjusted D-dimer had low nLR, allowing its use as a rule-out PE strategy in non-high pretest clinical probability patients, as well as using Vidas(®), Liatest(®) or MDA(®) assays. This age-adjusted cut-off increased clinical usefulness of D-dimer in older patients. A large prospective study is required to confirm these results.

Copy number changes on the X chromosome in women with and without highly skewed X-chromosome inactivation

AIM

To test the hypothesis that microdeletions or microduplications below the resolution of a standard karyotype may be a significant cause of highly skewed X-inactivation (HSXI) in women without a cytogenetically detected X-chromosome anomaly.

METHODS

Cases were women with HSXI, defined as ≥85% of cells in a blood sample with the same active allele at the HUMARA locus. The skewing in controls ranged from 50 to <75%. We performed an SNP microarray analysis using the Affymetrix 6.0 platform for 45 cases and 45 controls.

RESULTS

Cases and controls did not differ in the frequency of X-chromosome copy number changes ≥100 kb or in the frequency of copy number changes that contained genes. However, one woman with HSXI >90% in blood and left and right buccal smears had a 5.5-Mb deletion in Xp22.2p22.1. This deletion could affect the viability of male conceptions and may have led to the dysmorphology found in female carriers.

CONCLUSION

HSXI in a blood sample is rarely due to X-chromosome copy number changes detectable by microarray.

Trisomic pregnancy and intermediate CGG repeat length at the FMR1 locus

BACKGROUND

We hypothesized that trisomy arises as a function of the size of the oocyte pool, with risk increased among women with diminished pools. Diminished pools may cause primary ovarian failure, which has been associated with premutation and intermediate CGG repeat length at the Fragile X mental retardation (FMR1) locus. Thus, we hypothesized that the risk of trisomic pregnancy is increased among women with intermediate CGG repeat length on the FMR1 gene.

METHODS

The analysis drew on data from two hospital-based case-control studies. We compared 207 women with trisomic spontaneous abortions (SAs) to three comparison groups: 82 women with other chromosomally abnormal SAs, 99 women with chromosomally normal SAs and 537 women with live births (LBs), age matched to women with SAs. We defined the length of the CGG repeat in four ways: the biallelic mean, the genotypic mean, the length on allele 2 and the length on allele 1. We analyzed CGG repeat length as a categorical variable. All analyses were adjusted for site, age and ethnicity.

RESULTS

CGG repeat length did not differ significantly between women with trisomic SAs and any of the three comparison groups. For the biallelic mean, the adjusted odds ratio relating trisomy (versus LB controls) to the highest category (35.5-59.5 repeats) versus the modal category (26.5-30.0 repeats) was 1.5 (95% confidence interval (CI): 0.7, 3.1). Comparisons with the two SA control groups also showed increased odds of more repeats among trisomy cases. Results were similar when repeat length was defined by the genotypic mean or by the repeat length on allele 2. For allele 1, the odds of short (9-19) repeat length were lower, but not significantly so, for trisomy cases compared with LB controls. Excluding women with premutations (n= 2) from the analysis yielded an adjusted odds ratio of 1.4 (95% CI: 0.7, 2.9) for the biallelic mean.

CONCLUSIONS

Our data are equivocal. The direction of associations is consistent with the hypothesis that repeat length in the intermediate range is associated with trisomy. However, differences between the trisomy cases and the comparison groups are neither large nor statistically significant. Our data rule out odds ratios larger than about 3.

European and American suspected and confirmed pulmonary embolism populations: comparison and analysis

BACKGROUND

If the prevalence of pulmonary embolism (PE) differs significantly between the US and Europe, this observation could reduce the generalizability of diagnostic protocols for PE derived in either location.

OBJECTIVE

To determine possible causes and potential clinical consequences of these PE prevalence differences.

METHODS

Secondary analysis of three prospectively collected multicenter samples (two French and one from the US) including 3174 European and 7940 American PE-suspected patients in Emergency departments (ED) (117 for Europe and 12 for US). Comparison of clinical features, resource use and outcomes of European- and US-suspected PE populations in ED.

RESULTS

European patients evaluated for PE were significantly older and had a higher clinical pretest probability (CPP) for PE. The final PE prevalence was significantly higher in Europe, in the overall sample (26.5% vs. 7.6%) and in each level of CPP. Suspected European patients categorized as low CPP had a higher posttest probability than US low CPP patients. Suspected US patients categorized as high CPP had a much lower posttest probability of PE than in Europe. The mean number of tests performed for one PE diagnosis was lower in Europe (7.4 vs. 21.6). Among patients diagnosed with PE, European patients had a higher mean severity of illness score and a higher PE-mortality rate (3.4% vs. 0.7%).

CONCLUSIONS

Among patients suspected of a PE and those ultimately diagnosed with a PE, European patients had higher acuity, a higher pretest probability and worse outcome than US patients. The present study underscores the importance of disease prevalence for pretest probability scoring approaches and for significance interpretation of imaging tests.

PD10-06: Loss of the Retinoblastoma Tumor Suppressor (RB) in Triple Negative Breast Cancer Is Associated with a Favorable Prognosis

Introduction: The retinoblastoma tumor suppressor gene (RB), initially identified in the pediatric tumor retinoblastoma, has been shown to be functionally inactivated in a variety of other tumor types. RB functions as a key regulator of cell cycle progression and modulates the response to a variety of physiological and clinically relevant stresses. In breast cancer, loss of RB has been shown to have prognostic significance and influence therapeutic response; however, a comprehensive analyses of RB in triple negative breast cancer (TNBC) has not been performed. Although TNBC represents only 15–20% of breast cancers it accounts for approximately half of breast cancer deaths. A subset of patients with TNBC will have a dramatic and durable response to standard chemotherapy. However, currently there are no markers that identify this patient subset. Since RB loss impinges on the response to chemotherapy, the goal of this study was to investigate the impact of RB-status on clinical management of TNBC.

Material and Methods: A cohort of 220 patients diagnosed and treated at Thomas Jefferson University Hospital was included in the study. RB-status was evaluated by immunohistochmistry (IHC) using 3 markers: p16ink4a (MTM Laboratories, Cat #: 9518,1:50 dilution), Ki67 (AbCam, Cat #: ab16667, 1:600 dilution) and RB (Thermoscientific, Cat #: MS-107-B, 1:50 dilution) through automated image analysis (Aperio). Cases were considered negative for RB when no neoplastic cell nuclei demonstrated labeling in sections in which stromal cells and endothelial cells stained; Ki67 and p16ink4 were scored using established published criteria. Gene expression profiling was performed on 12 cases (6 RB positive and 6 RB negative by IHC) and RB pathway status in these samples was evaluated using an RB-loss signature developed by our group. Parallel analyses of TNBC expression data sets were also employed to define the relationship of the RB pathway with clinical outcome. Overall survival was analyzed using LogRank test and Cox proportional hazard model. Data were analyzed in SAS 9.1 (SAS Institute Inc., Cary, NC, USA).

Results: 176 patients had samples that could be scored for RB, p16ink4 and Ki67 expression. 46% (71/176) showed RB loss. RB loss was associated with high p16ink4a expression and high Ki67 proliferation index in 93% (66/71) of samples and correlated with RB loss signature in all but one sample. RB loss and high p16ink4 expression was associated with a longer overall survival in this cohort (p=0.003). In contrast, patients with TNBC showing RB positivity and high p16ink4 had the worse survival (median survival 4 months, 10 year survival 23%). These findings were consistent with gene expression profiling data that indicate specific loss of RB function in TNBC is associated with improved response to chemotherapy and improved survival.

Conclusion: RB loss appears to be a predictor of a favorable clinical outcome in TNBC treated with conventional adjuvant chemotherapy.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD10-06.

Abstract P1-15-02: Impact of Retinoblastoma (RB) Tumor Suppressor Pathway on Ductal Carcinoma In Situ (DCIS) Recurrence

The retinoblastoma (RB) tumor suppressor is functionally inactivated at high frequency in human malignancies including breast cancer. By immunohistochemistry loss of RB function is associated with p16ink4a overexpression and high Ki67 proliferation index.We have previously shown that loss of RB results in dramatic upregulation of genes associated with tumorigenesis and is a key determinant of therapeutic response in invasive breast carcinoma. Recently publish data indicate that RB pathway dysregulation plays an important role in DCIS progression to invasive carcinoma. The aim of this study was to evaluate the expression p16ink4a and Ki67 (indicative of RB loss) in a large cohort of DCIS patients treated at one institution with wide-excision and close follow-up. Material and Methods

149 DCIS patients were included in the study. Expression of p16ink4a and Ki67 was assessed by employing a standard immunoperoxidase method with ani-p16ink4a (MTM Laboratories Westborough, MA) and anti-Ki67 (AbCam Cambridge, MA) antibodies. The p16ink4a staining in DCIS epithelium was scored semi-quantitatively as negative (0; no staining), weak (1;staining in less than 25% of cells), moderate (2; defined as staining in 25-75% of cells) and strong (3; &gt;75% of cells staining). For statistical analysis, the original p16ink4a scores (0, 1, 2, 3) were dichotomized as low (0,1) vs. high (2-3) and original ki67 scores were dichotomized as low (&lt;= 10%) vs. high (&gt; 10%). Stromal p16 staining was scored as absent or present.

Association between p16ink4a and Ki67 and nuclear grade, necrosis, hormone receptor and Her2 expression as well as recurrence was assessed using Fisher's exact test. The Cox proportional hazard model was used for analyses of time to recurrence. Results

There was a statistically significant association between high p16ink4a and Ki67 expression in DCIS epithelium and triple negative as well as Her2 positive DCIS subtypes. Significant association was detected between high expression of p16 and Ki67 in DCIS epithelium and DCIS recurrence (p=0.005). Stromal expression of p16 was the strongest predictor of DCIS recurrence (p &lt; 0.0001). In multivariate Cox model DCIS cases with high expression of p16 and Ki67 in epithelium and stromal p16 expression had the shortest time to recurrence.

Conclusion

RB pathway dysregulation in DCIS epithelium as well as stromal expression of p16ink4a indicative of senescence are associated with DCIS recurrence.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-15-02.

Development of a short duration backlit pinhole for radiography on the National Ignition Facility

Experiments on the National Ignition Facility (NIF) will require bright, short duration, near-monochromatic x-ray backlighters for radiographic diagnosis of many high-energy density systems. This paper details a vanadium pinhole backlighter producing (1.8±0.5)×10(15) x-ray photons into 4π sr near the vanadium He-like characteristic x-ray energy of 5.18 keV. The x-ray yield was quantified from a set of Ross filters imaged to a calibrated image plate, with the Dante diagnostic used to confirm the quasimonochromatic nature of the spectrum produced. Additionally, an x-ray film image shows a source-limited image resolution of 26 μm from a 20 μm diameter pinhole.