The Halo Beaming Model for Gamma-Ray Bursts

We consider a model for gamma-ray bursts (GRBs) from high-velocity neutron stars in the galactic halo. In this model, bursters are born in the galactic disk with large recoil velocities V_r, and GRBs are beamed to within emission cones of half-angle \phi centered on V_r. We describe scenarios for magnetically -channeled GRBs that have such beaming characteristics. We then make detailed comparisons of this halo beaming model (HBM) to BATSE and PVO data for GRB intensity & angular position distributions. Acceptable fits to observations of over 1000 bursts are obtained for \phi = 15 - 30 degrees and for a BATSE sampling depth ~ 180 kpc. Present data favor a truly isotropic (cosmological) model over the HBM, but not by a statistically compelling margin. Bursters born in nearby external galaxies, such as M31, are almost entirely undetectable in the HBM because of misdirected beaming. We analyze several refinements of the basic HBM: gamma-ray intensities that vary with angle from the beam axis; non-standard-candle GRB luminosity functions; and models including a subset of bursters that do not escape from the galaxy. We also discuss the energy budgets for the bursters, the origins of their recoils, and the physics of burst beaming and alignment. One possible physical model is based on the magnetar model of soft gamma repeaters (SGRs). Empirical bounds on the rate of formation and peculiar velocities of SGRs imply that there exist ~ 10^4 to ~ 10^7 aged SGRs in the galactic halo within a distance of 100 kpc. The HBM gives an acceptable fit to observations only if it satisfies certain conditions (e.g. \phi ~ 20 deg) which are possible, but for which there exist no clear & compelling theoretical justifications. The cosmological burster hypothesis is more generic and thus more attractive in this sense. (Abbreviated Abstract).Comment: ApJ accepted, 9 figures, AASTE

Endoscopic balloon dilatation for congenital membranous stenosis in the jejunum in an infant.

INTRODUCTION: As endoscopic equipment and instruments have improved, the indications for endoscopic treatment have also been extended. This report presents an applicable procedure of endoscopic balloon dilatation for an infant patient with congenital membranous stenosis in the jejunum. METHODS: We used a 9-mm flexible endoscope and a through-the-scope multidiameter balloon catheter in the endoscopic treatment. RESULTS: Dilatation was performed for dilatation diameters 10, 12, and 15 mm each for 2 min. After carrying out balloon dilatation, the endoscope could be smoothly inserted through the opening. CONCLUSION: In upper jejunal stenosis, endoscopic balloon dilatation was minimally invasive and effective as a treatment modality.The original publication is available at www.springerlink.co

Inert coupling of IRDye800CW to monoclonal antibodies for clinical optical imaging of tumor targets

Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas

Molecular imaging of angiogenesis with SPECT

Single-photon emission computed tomography (SPECT) and position emission tomography (PET) are the two main imaging modalities in nuclear medicine. SPECT imaging is more widely available than PET imaging and the radionuclides used for SPECT are easier to prepare and usually have a longer half-life than those used for PET. In addition, SPECT is a less expensive technique than PET. Commonly used gamma emitters are: 99mTc (Emax 141 keV, T1/2 6.02 h), 123I (Emax 529 keV, T1/2 13.0 h) and 111In (Emax 245 keV, T1/2 67.2 h). Compared to clinical SPECT, PET has a higher spatial resolution and the possibility to more accurately estimate the in vivo concentration of a tracer. In preclinical imaging, the situation is quite different. The resolution of microSPECT cameras (<0.5 mm) is higher than that of microPET cameras (>1.5 mm). In this report, studies on new radiolabelled tracers for SPECT imaging of angiogenesis in tumours are reviewed

Investigation for cystic fibrosis in infants with jejunoileal atresia in the Netherlands: a 35-year experience with 114 cases.

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