1,383 research outputs found

    Noninvasive Evaluation of Microcirculation under Normal and Pathological Conditions Using Contrast-Enhanced Ultrasonography (CEUS)

    Get PDF
    The present chapter highlights the most important information about microcirculation and its evaluation using contrast-enhanced ultrasonography (CEUS). In the beginning it outlines some general considerations about microcirculation, together with its morphological and physiological particularities under normal and pathological circumstances. The ultrasonographic (US) evaluation of vascularity is based on the Doppler technique and the harmonic technique using contrast agents. Then it presents briefly the Doppler ultrasound (DUS) and discusses its most important current and emerging indications. CEUS is presented extensively, covering the fundamentals of sonographic contrast agents, harmonic imaging and quantification techniques. A special focus is placed not only on the current and emerging indications of CEUS but also on the advantages and limitations of the method. This chapter also incorporates information about experimental CEUS applications and future perspectives. CEUS is the recommended US method for the characterization of microcirculation. The results of the examination are displayed in real-time, under the eyes of the examiner, while the quantitative assessment of the contrast agent kinetics parameters is easy to perform. This method allows a precise definition of the healthy or pathologic state of an organ and the follow-up of treatment response

    Imaging of Colonic and Rectal Cancer

    Get PDF
    Colorectal cancer is one of the most common cancers worldwide. Thus, its early detection through screening and diagnostic techniques is the key in managing this condition. For this to be possible, it is necessary to know the risk factors and to choose the appropriate screening and diagnostic techniques for each case. Imaging also plays a key role in treatment planning by assessing both local and distance extension of the disease

    Mononuclear Cu(II) complexes of novel salicylidene Schiff bases: synthesis and mesogenic properties

    Get PDF
    Two new Schiff base ligands 1 and 2 (where 1 = 4-(2-hydroxybenzilidenamino)-phenyl-4-(decyloxy)-2-(pent-4-enyloxy)benzoate, 2 = 4-(4-(decyloxy)-2-hydroxybenziliden amino)-phenyl-4-(decyloxy)-2-(pent-4-enyloxy)benzoate) and their copper (Cu)(II) complexes have been synthesised and characterised. The derivatives were fully characterised structurally, and their mesomorphic behaviour was investigated by polarised optical microscopyand differential scanning calorimetry. The structure of Cu(II) complex having 1 as ligand (3) was determined by X-ray diffraction. The Schiff base ligands exhibit enantiotropic nematic phases, the Cu(II) complex 4 shows monotropic nematic phase behaviour, while compound 3 does not show mesomorphism

    Mining the ESO WFI and INT WFC archives for known Near Earth Asteroids. Mega-Precovery software

    Full text link
    The ESO/MPG WFI and the INT WFC wide field archives comprising 330,000 images were mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 152 asteroids (44 PHAs and 108 other NEAs) were identified using the PRECOVERY software, their astrometry being measured on 761 images and sent to the Minor Planet Centre. Both recoveries and precoveries were reported, including prolonged orbital arcs for 18 precovered objects and 10 recoveries. We analyze all new opposition data by comparing the orbits fitted before and after including our contributions. We conclude the paper presenting Mega-Precovery, a new online service focused on data mining of many instrument archives simultaneously for one or a few given asteroids. A total of 28 instrument archives have been made available for mining using this tool, adding together about 2.5 million images forming the Mega-Archive.Comment: Accepted for publication in Astronomische Nachrichten (Sep 2012

    Thermal Analysis of 480 volt Disconnect Switches Feeding Thyristor Control Power Supplies

    Get PDF
    N/

    Simulations of the Ags Mmps Storing Energy in Capacitor Banks

    Get PDF
    The Brookhaven AGS Main Magnet Power Supply (MMPS) is a thyristor control supply rated at 5500 Amps, +/-9000 Volts. The peak magnet power is 50 MWatts. The power supply is fed from a motor/generator manufactured by Siemens. The generator is 3 phase 7500 Volts rated at 50 MVA. The peak power requirements come from the stored energy in the rotor of the motor/generator. The motor generator is about 45 years old, made by Siemens and it is not clear if companies will be manufacturing similar machines in the future. We are therefore investigating different ways of storing energy for future AGS MMPS operations. This paper will present simulations of a power supply where energy is stored in capacitor banks. Two dc to dc converters will be presented along with the control system of the power section. The switching elements will be IGCT's made by ABB. The simulation program used is called PSIM version 6.1. The average power from the local power authority into the power supply will be kept constant during the pulsing of the magnets at +/-50 MW. The reactive power will also be kept constant below 1.5 MVAR. Waveforms will be presented

    Behavior of bipyridine derivative Cu(I) complexes in donor solvents

    Get PDF
    Cu(I) complexes are known as highly emissive compounds having interesting fluorescence applications[1].Theluminescence is generated by more intense metal to ligand charge transfer (MLCT) electronic transitions for Cu(I), affording longer excited-statelifetimes compared to transient d-d excited state of Cu(II)[2].Herein we report the behavior of two bipyridine derivative Cu(I) complexes containing phenanthroline and biquinoline ligands, respectively, in donor solvents as dimethylsulfoxide and acetonitrile.The Cu(I) phenanthroline complex (1) is unstable in solution,due to oxidation of Cu(I) to Cu(II) in time, accompanied by change in coordination geometry from tetrahedral to trigonal bipyramidal. The Cu(I) biquinoline complex (2) is more stable in donor solvents,the stability increasing at low temperatures with the stabilization of tetragonal geometry of Cu(I).In case of biquinoline ligand, this kind of geometry is stabilized by the bulky aryl substituentsatαposition with respect to the pyridine nitrogen
    • …
    corecore