The existence of hot, two-temperature accretion flows is essential to the recent discussions of the low luminosity, hard X-ray emission from accreting neutron stars and black holes in Galactic binaries and massive black holes in low luminosity galactic nuclei. In these flows, protons are essentially virialized and relativistic energies for non-thermal protons are likely. Observational confirmat...

The spectral energy distribution (SED) of blazars typically has a double-humped appearance usually interpreted in terms of synchrotron self-Compton models. In proton blazar models, the SED is instead explained in terms of acceleration of protons and subsequent cascading. We discuss a variation of the Synchrotron Proton Blazar model, first proposed by Mücke & Protheroe (1999), in which the low e...

Introduction: Proton therapy delivers radiation to tumor tissue in a much more confined way than conventional photon therapy thus allowing the radiation oncologist to use a greater dose while still minimizing side.   Materials and Methods: protons release most of their energy within the tumor region. As a result, the treating physician can potentially give an...

The heme-copper oxidase (HCuO) superfamily consists of integral membrane proteins that catalyze the reduction of either oxygen or nitric oxide. The HCuOs that reduce O(2) to H(2)O couple this reaction to the generation of a transmembrane proton gradient by using electrons and protons from opposite sides of the membrane and by pumping protons from inside the cell or organelle to the outside. The...

Chemical exchange saturation transfer (CEST) agents represent an emerging class of magnetic resonance imaging (MRI) contrast media that has huge potential. They act as negative agents by reducing the signal intensity of the water protons through a saturation transfer mediated by chemical exchange. Saturation transfer occurs through selective irradiation at the absorption frequency of the exchan...

A hybrid silicon pixelated TIMEPIX detector (256 × 256 square pixels with a pitch of 55 μm) operated in Time Over Threshold (TOT) mode was exposed to radioactive sources and protons after Rutherford Backscattering on a thin gold foil of protons beams delivered by the Tandem Accelerator of the Montreal University. Simultaneous exposure of TIMEPIX to radioactive sources and to protons beams on to...

Purpose: A comparative treatment planning study has been undertaken between standard photon delivery techniques,b intensity modulated photon methods and spot scanned protons in order to investigate the merits and limitations of each of these treatment approaches. Methods: Plans for each modality were performed using CT scans and planning information for nine patients with varying indications an...