318 research outputs found

    Radio Sources in Galaxy Clusters at 28.5 GHz

    Get PDF
    We present serendipitous detections of radio sources at 28.5 GHz (1 cm), which resulted from our program to image thermal Sunyaev-Zeldovich (SZ) effect in 56 galaxy clusters. We find 64 radio sources with fluxes down to 0.4 mJy, and within 250 arcseconds from the pointing centers. The spectral indices (S ~ \nu^-\alpha) of 54 sources with published low frequency flux densities range from -0.6 to 2 with a mean of 0.77, and a median of 0.84. Extending low frequency surveys of radio sources towards galaxy clusters CL 0016+16, Abell 665, and Abell 2218 to 28.5 GHz, and selecting sources with 1.4 GHz flux density greater than 7 mJy to form an unbiased sample, we find a mean spectral index of 0.71 and a median of 0.71. We find 4 to 7 times more sources predicted from a low frequency survey in areas without galaxy clusters. This excess cannot be accounted for by gravitational lensing of a background radio population by cluster potentials, indicating most of the detected sources are associated with galaxy clusters. For the cluster Abell 2218, the presence of unsubtracted radio sources with 28.5 GHz flux densities less than 0.5 mJy, can only contribute to temperature fluctuations at a level of 10 to 25 \muK. The corresponding error due to radio point source contamination in the Hubble constant derived through a combined analysis of 28.5 GHz SZ images and X-ray emission observations ranges from 1% to 6%.Comment: 18 pages, 8 figures, to appear in April 1998 issue of A

    Parsec Scale Properties of Markarian 501

    Full text link
    We present the results of a high angular resolution study of the BL Lac object Markarian 501 in the radio band. We consider data taken at 14 different epochs, ranging between 1.6 GHz and 22 GHz in frequency, and including new Space VLBI observations obtained on 2001 March 5 and 6 at 1.6 and 5 GHz. We study the kinematics of the parsec-scale jet and estimate its bulk velocity and orientation with respect to the line of sight. Limb brightened structure in the jet is clearly visible in our data and we discuss its possible origin in terms of velocity gradients in the jet. Quasi-simultaneous multi-wavelength observations allow us to map the spectral index distribution and to compare it to the jet morphology. Finally, we estimate the physical parameters of the parsec-scale jet.Comment: accepted for publication in ApJ; 24 pages with 17 figures (fig. 1 and fig. 2 available only as .jpg files

    Discovery of the low-energy cutoff in a powerful giant radio galaxy

    Get PDF
    The lobes of radio galaxies and quasars, fed by jets and hotspots, represent a significant, and currently ill-constrained, source of energy input into the inter-galactic medium (IGM). How much energy is input into the IGM depends on the minimum energy to which the power-law distribution of relativistic particles is accelerated in the hotspots. This has hitherto been unknown to within three orders of magnitude. We present direct evidence for the discovery of this low-energy cutoff in the lobe of a Mpc-sized radio galaxy via the existence of extended X-ray emission, inverse-Compton scattered from aged radio plasma, and its separation by 80kpc from regions containing freshly accelerated plasma from the hotspot. The low-energy cutoff of gamma ~ 10^4 in the hotspot is higher than previously thought, but reconciles discrepancies with magnetic field estimates which had been systematically lower than equipartition values. The inverse Compton scattering of the spent synchrotron plasma is at the expense of cosmic microwave background (CMB) photons; we comment on the importance of such giant radio galaxies as contaminants of CMB anisotropies.Comment: Accepted by Ap J Letter

    Radio Frequency Spectra of 388 Bright 74 MHz Sources

    Full text link
    As a service to the community, we have compiled radio frequency spectra from the literature for all sources within the VLA Low Frequency Sky Survey (VLSS) that are brighter than 15 Jy at 74 MHz. Over 160 references were used to maximize the amount of spectral data used in the compilation of the spectra, while also taking care to determine the corrections needed to put the flux densities from all reference on the same absolute flux density scale. With the new VLSS data, we are able to vastly improve upon previous efforts to compile spectra of bright radio sources to frequencies below 100 MHz because (1) the VLSS flux densities are more reliable than those from some previous low frequency surveys and (2) the VLSS covers a much larger area of the sky (declination >-30 deg.) than many other low frequency surveys (e.g., the 8C survey). In this paper, we discuss how the spectra were constructed and how parameters quantifying the shapes of the spectra were derived. Both the spectra and the shape parameters are made available here to assist in the calibration of observations made with current and future low frequency radio facilities.Comment: Accepted to ApJ

    Catalog of Radio Galaxies with z>0.3. I:Construction of the Sample

    Full text link
    The procedure of the construction of a sample of distant (z>0.3z>0.3) radio galaxies using NED, SDSS, and CATS databases for further application in statistical tests is described. The sample is assumed to be cleaned from objects with quasar properties. Primary statistical analysis of the list is performed and the regression dependence of the spectral index on redshift is found.Comment: 9 pages, 6 figures, 2 table

    Efficacy and safety of a hexanic extract of Serenoa repens (Permixon (R)) for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH): systematic review and meta-analysis of randomised controlled trials and observational studies

    Get PDF
    Objectives To comprehensively evaluate the efficacy and safety of the hexanic extract of Serenoa repens (HESr, Permixon (R); Pierre Fabre Medicament, Castres, France), at a dose of 320 mg daily, as monotherapy for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH). Materials and methods We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) and prospective observational studies in patients with LUTS/BPH identified through searches in Medline, Web of Knowledge (Institute for Scientific Information), Scopus, the Cochrane Library, and bibliographic references up to March 2017. Articles studying S. repens extracts other than Permixon were excluded. Data were collected on International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), nocturia, quality of life, prostate volume, sexual function, and adverse drug reactions (ADRs). Data obtained from RCTs and observational studies were analysed jointly and separately using a random effects model. A sub-group analysis was performed of studies that included patients on longer-term treatment (= 1 year). Results Data from 27 studies (15 RCTs and 12 observational studies) were included for meta-analysis (total N = 5 800). Compared with placebo, the HESr was associated with 0.64 (95% confidence interval [CI] -0.98 to -0.31) fewer voids/ night (P < 0.001) and an additional mean increase in Q(max) of 2.75 mL/s (95% CI 0.57 to 4.93; P = 0.01). When compared with a-blockers, the HESr showed similar improvements on IPSS (weighted mean difference [WMD] 0.57, 95% CI -0.27 to 1.42; P = 0.18) and a comparable increase in Q(max) to tamsulosin (WMD -0.02, 95% CI -0.71 to 0.66; P = 0.95). Efficacy assessed using the IPSS was similar after 6 months of treatment between the HESr and 5a-reductase inhibitors (5ARIs). Analysis of all available published data for the HESr showed a mean improvement in IPSS from baseline of -5.73 points (95% CI -6.91 to -4.54; P < 0.001). HESr did not negatively affect sexual function and no clinically relevant effect was observed on prostate-specific antigen. Prostate volume decreased slightly. Similar efficacy results were seen in patients treated for = 1 year (n = 447). The HESr had a favourable safety profile, with gastrointestinal disorders being the most frequent ADR (mean incidence of 3.8%). Conclusion The present meta-analysis, which includes all available RCTs and observational studies, shows that the HESr (Permixon) reduced nocturia and improved Q(max) compared with placebo and had a similar efficacy to tamsulosin and short-term 5ARI in relieving LUTS. HESr (Permixon) appears to be an efficacious and well-tolerated therapeutic option for the longterm medical treatment of LUTS/BPH

    Advanced Technologies for Oral Controlled Release: Cyclodextrins for oral controlled release

    Get PDF
    Cyclodextrins (CDs) are used in oral pharmaceutical formulations, by means of inclusion complexes formation, with the following advantages for the drugs: (1) solubility, dissolution rate, stability and bioavailability enhancement; (2) to modify the drug release site and/or time profile; and (3) to reduce or prevent gastrointestinal side effects and unpleasant smell or taste, to prevent drug-drug or drug-additive interactions, or even to convert oil and liquid drugs into microcrystalline or amorphous powders. A more recent trend focuses on the use of CDs as nanocarriers, a strategy that aims to design versatile delivery systems that can encapsulate drugs with better physicochemical properties for oral delivery. Thus, the aim of this work was to review the applications of the CDs and their hydrophilic derivatives on the solubility enhancement of poorly water soluble drugs in order to increase their dissolution rate and get immediate release, as well as their ability to control (to prolong or to delay) the release of drugs from solid dosage forms, either as complexes with the hydrophilic (e.g. as osmotic pumps) and/ or hydrophobic CDs. New controlled delivery systems based on nanotechonology carriers (nanoparticles and conjugates) have also been reviewed

    A novel patient-derived tumorgraft model with TRAF1-ALK anaplastic large-cell lymphoma translocation.

    Get PDF
    Although anaplastic large-cell lymphomas (ALCL) carrying anaplastic lymphoma kinase (ALK) have a relatively good prognosis, aggressive forms exist. We have identified a novel translocation, causing the fusion of the TRAF1 and ALK genes, in one patient who presented with a leukemic ALK+ ALCL (ALCL-11). To uncover the mechanisms leading to high-grade ALCL, we developed a human patient-derived tumorgraft (hPDT) line. Molecular characterization of primary and PDT cells demonstrated the activation of ALK and nuclear factor kB (NFkB) pathways. Genomic studies of ALCL-11 showed the TP53 loss and the in vivo subclonal expansion of lymphoma cells, lacking PRDM1/Blimp1 and carrying c-MYC gene amplification. The treatment with proteasome inhibitors of TRAF1-ALK cells led to the downregulation of p50/p52 and lymphoma growth inhibition. Moreover, a NFkB gene set classifier stratified ALCL in distinct subsets with different clinical outcome. Although a selective ALK inhibitor (CEP28122) resulted in a significant clinical response of hPDT mice, nevertheless the disease could not be eradicated. These data indicate that the activation of NFkB signaling contributes to the neoplastic phenotype of TRAF1-ALK ALCL. ALCL hPDTs are invaluable tools to validate the role of druggable molecules, predict therapeutic responses and implement patient specific therapies
    corecore