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Bow Tie

I Chaikovska, K Cassou, R Chiche, R Cizeron, P Cornebise, N Delerue, D Jehanno, F Labaye, R Marie, A Martens, Y Peinaud, V Soskov, A Variola, F Zomer, E Cormier, J Lhermite, V Dolique, R Flaminio, C Michel, L Pinard, B Sassolas, T Akagi, S Araki, Y Honda, T Omori, N Terunuma, J Urakawa, S Miyoshi, T Takahashi, H Yoshitama
We report and discuss high-flux generation of circularly polarized γ-rays by means of Compton scattering. The γ-ray beam results from the collision of an external-cavity-enhanced infrared laser beam and a low emittance relativistic electron beam. By operating a non-planar bow-tie high-finesse optical Fabry-Perot cavity coupled to a storage ring, we have recorded a flux of up to (3.5 ± 0.3) × 10(8) photons per second with a mean measured energy of 24 MeV. The γ-ray flux has been sustained for several hours...
November 18, 2016: Scientific Reports
Eva Oberacker, Katharina Paul, Till Huelnhagen, Celal Oezerdem, Lukas Winter, Andreas Pohlmann, Laura Boehmert, Oliver Stachs, Jens Heufelder, Andreas Weber, Matus Rehak, Ira Seibel, Thoralf Niendorf
PURPOSE: Proton radiation therapy (PRT) is a standard treatment of uveal melanoma. PRT patients undergo implantation of ocular tantalum markers (OTMs) for treatment planning. Ultra-high-field MRI is a promising technique for 3D tumor visualization and PRT planning. This work examines MR safety and compatibility of OTMs at 7.0 Tesla. METHODS: MR safety assessment included deflection angle measurements (DAMs), electromagnetic field (EMF) simulations for specific absorption rate (SAR) estimation, and temperature simulations for examining radiofrequency heating using a bow-tie dipole antenna for transmission...
November 10, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
M D Culwick, A F Merry, D M Clarke, K J Taraporewalla, N M Gibbs
Bow-tie analysis is a risk analysis and management tool that has been readily adopted into routine practice in many high reliability industries such as engineering, aviation and emergency services. However, it has received little exposure so far in healthcare. Nevertheless, its simplicity, versatility, and pictorial display may have benefits for the analysis of a range of healthcare risks, including complex and multiple risks and their interactions. Bow-tie diagrams are a combination of a fault tree and an event tree, which when combined take the shape of a bow tie...
November 2016: Anaesthesia and Intensive Care
Hans-Erik Källman, Rickard Holmberg, Jonas Andersson, Love Kull, Erik Tranéus, Anders Ahnesjö
PURPOSE: Radiation dose to patients undergoing examinations with Multislice Computed Tomography (MSCT) as well as Cone Beam Computed Tomography (CBCT) is a matter of concern. Risk management could benefit from efficient replace rational dose calculation tools. The paper aims to verify MSCT dose calculations using a Treatment Planning System (TPS) for radiotherapy and to evaluate four different variations of bow-tie filter characterizations for the beam model used in the dose calculations...
November 2016: Medical Physics
Esmaeil Zarei, Ali Azadeh, Nima Khakzad, Iraj Mohammadfam
Pipelines are one of the most popular and effective ways of transporting hazardous materials, especially natural gas. However, the rapid development of gas pipelines and stations in urban areas has introduced a serious threat to public safety and assets. Although different methods have been developed for risk analysis of gas transportation systems, a comprehensive methodology for risk analysis is still lacking, especially in natural gas stations. The present work is aimed at developing a dynamic and comprehensive quantitative risk analysis (DCQRA) approach for accident scenario and risk modeling of natural gas stations...
October 1, 2016: Journal of Hazardous Materials
Yong Hyun Kim, Hong Kwon, Jeongjun Kim, Kwang Yong Song
High-sensitivity distributed measurement of hydrostatic pressure is experimentally demonstrated by optical time-domain analysis of Brillouin dynamic grating (BDG) in polarization maintaining fibers (PMF's). The spectral shift of the BDG in four different types of PMF's are investigated under hydrostatic pressure variation from 14.5 psi (1 bar) to 884.7 psi (61 bar) with less than 2 m spatial resolution. The pressure sensitivity of BDG frequency is measured to be ‒1.69, + 0.65, + 0.78, and + 0.85 MHz/psi for a PM photonic crystal fiber (PM-PCF), two Bow-tie fibers, and a PANDA fiber, respectively, which is about 65 to 169 times larger than that of Brillouin frequency-based pressure sensing...
September 19, 2016: Optics Express
S Chegini, A De Leo, S Tucker
No abstract text is available yet for this article.
September 23, 2016: Annals of the Royal College of Surgeons of England
Jochen Wueppen, Sebastian Nyga, Bernd Jungbluth, Dieter Hoffmann
We report on an optical parametric oscillator that generates output idler wavelengths around 10.6 μm. On the basis of orientation-patterned gallium arsenide (OP-GaAs) as a nonlinear medium and a 1.95 μm ns-pulsed pump laser, a signal-resonant bow-tie resonator was designed in order to maximize the output power at moderate intensities well below the damage threshold of the optical components. With this setup, the average idler output power at 50 kHz and 100 ns idler pulse length was more than 800 mW, which corresponds to a pulse energy of 16 μJ...
September 15, 2016: Optics Letters
Lia Florim Patrão, Ana Laura Caiado Canedo, João Luiz Peixoto Braga de Azevedo, Rosane Correa, Renato Ambrósio
We report two cases of suspicious asymmetric bow tie and inferior steepening on topographic evaluations with reflection (Placido) and projection (Scheimpflug). Rotating Scheimpflug corneal and anterior segment tomography (Oculus Pentacam HR, Wetzlar, Germany)® was performed in the first case, with a maximal keratometric value (Kmax) of 43.2 D and an overall deviation value from the Belin/Ambrósio Enhanced Ectasia Display (BAD-D) of 1.76, which was observed in the study eye (OD). BAD-D was 6.59 in the fellow eye, which had clinical findings that were consistent with keratoconus stage 2...
July 2016: Arquivos Brasileiros de Oftalmologia
Zhong-Jian Yang, Tomasz J Antosiewicz, Timur Shegai
We investigate the role of material loss and mode volume of plasmonic nanostructures on strong plasmon-exciton coupling. We find that the field enhancement, and therefore loss, is not important for the magnitude of the Rabi splitting as such, but instead it is determined by the mode volume. Nevertheless, for reaching true strong coupling condition, that is, coupling greater than any dissipation, it is important to compromise losses. We also show that using such popular geometries as a dimer of two spheres or bow-tie nanoantennas, does not allow compressing the mode volume much in comparison to a single nanoparticle case, except for very narrow gaps, but rather it allows for efficient extraction of the mode out of the metal thus making it more accessible for excitons to interact with...
September 5, 2016: Optics Express
Naoki Yamamoto
A high-resolution cathodoluminescence (CL) system for scanning transmission electron microscope (STEM) has been developed by employing a field emission gun and a spherical aberration corrector, which realizes a probe size of 1 nm even at an accelerating voltage of 80 kV and beam current of the order of 1 nA. Angle resolved measurement of light emission from a sample in the STEM is possible by combining a parabolic mirror and position-controlled pinhole. CL spectra are successively acquired by a highly sensitive charge-coupled device while scanning the incident electron beam or pinhole, which enables various detection modes, i...
August 2016: Microscopy
Angelina Müller, Matthias C Wapler, Ulrich T Schwarz, Markus Reisacher, Katarzyna Holc, Oliver Ambacher, Ulrike Wallrabe
We study the spatial intensity distribution and the self-reconstruction of quasi-Bessel beams produced from refractive axicon lenses with edge emitting laser diodes as asymmetric and astigmatic illumination sources. Comparing these to a symmetric mono-mode fiber source, we find that the asymmetry results in a transition of a quasi-Bessel beam into a bow-tie shaped pattern and eventually to a line shaped profile at a larger distance along the optical axis. Furthermore, we analytically estimate and discuss the effects of astigmatism, substrate modes and non-perfect axicons...
July 25, 2016: Optics Express
Fang Yan, Kaili Xu, Xiwen Yao, Yang Li
Biomass gasification technology has been rapidly developed recently. But fire and poisoning accidents caused by gas leakage restrict the development and promotion of biomass gasification. Therefore, probabilistic safety assessment (PSA) is necessary for biomass gasification system. Subsequently, Bayesian network-bow-tie (BN-bow-tie) analysis was proposed by mapping bow-tie analysis into Bayesian network (BN). Causes of gas leakage and the accidents triggered by gas leakage can be obtained by bow-tie analysis, and BN was used to confirm the critical nodes of accidents by introducing corresponding three importance measures...
2016: PloS One
Tomonobu Haba, Shuji Koyama, Yutaka Kinomura, Yoshihiro Ida, Masanao Kobayashi
The American Association of Physicists in Medicine (AAPM) task group 204 has recommended the use of size-dependent conversion factors to calculate size-specific dose estimate (SSDE) values from volume computed tomography dose index (CTDIvol) values. However, these conversion factors do not consider the effects of 320-detector-row volume computed tomography (CT) examinations or the new CT dosimetry metrics proposed by AAPM task group 111. This study aims to investigate the influence of these examinations and metrics on the conversion factors reported by AAPM task group 204, using Monte Carlo simulations...
September 2016: Australasian Physical & Engineering Sciences in Medicine
Eric M Schmidt, Shalini Gupta, Thomas Bowe, Laura S Ellerbe, Tyler E Phelps, John W Finney, Steven M Asch, Keith Humphreys, Jodie Trafton, Megan Vanneman, Alex H S Harris
BACKGROUND: Measures of substance use disorder (SUD) treatment quality are essential tools for performance improvement. The Veterans Health Administration (VHA) developed a measure of access to and engagement in intensive outpatient programs (IOP) for SUD. However, predictive validity, or associations between this measure and treatment outcomes, has not been examined. METHODS: Data on veterans with SUD came from three samples: the Outcomes Monitoring Project (N = 5,436), a national evaluation of VHA mental health services (N = 339,887), and patients receiving detoxification services (N = 23,572)...
July 19, 2016: Substance Abuse
Tomonobu Haba, Shuji Koyama, Takahiko Aoyama, Yutaka Kinomura, Yoshihiro Ida, Masanao Kobayashi, Hiroshi Kameyama, Yoshinori Tsutsumi
PURPOSE: Patient dose estimation in X-ray computed tomography (CT) is generally performed by Monte Carlo simulation of photon interactions within anthropomorphic or cylindrical phantoms. An accurate Monte Carlo simulation requires an understanding of the effects of the bow-tie filter equipped in a CT scanner, i.e. the change of X-ray energy and air kerma along the fan-beam arc of the CT scanner. To measure the effective energy and air kerma distributions, we devised a pin-photodiode array utilizing eight channels of X-ray sensors arranged at regular intervals along the fan-beam arc of the CT scanner...
July 2016: Physica Medica: PM
Ali Mirzajani, Sattar Aghataheri, Mohammad Ghoreishi, Ebrahim Jafarzadepour, Mohadese Mohammadinia
PURPOSE: This study reports the characteristics of corneal higher order aberrations (HOAs) in eyes with normal topographic pattern using the Pentacam scheimpflug system. METHODS: In this prospective, observational, comparative study, 165 eyes of 97 patients separated into five groups based on corneal topographic patterns were enrolled. All eyes received a comprehensive ophthalmologic examination including corneal tomographic analysis with the Pentacam system. Keratometry, corneal cylinder, and corneal aberrometric data were recorded and analyzed...
June 2016: Journal of Current Ophthalmology
Annie Janvier
No abstract text is available yet for this article.
August 1, 2016: JAMA Pediatrics
Zhaleh Abdi, Hamid Ravaghi, Mohsen Abbasi, Bahram Delgoshaei, Somayeh Esfandiari
Purpose - The purpose of this paper is to apply Bow-tie methodology, a proactive risk assessment technique based on systemic approach, for prospective analysis of the risks threatening patient safety in intensive care unit (ICU). Design/methodology/approach - Bow-tie methodology was used to manage clinical risks threatening patient safety by a multidisciplinary team in the ICU. The Bow-tie analysis was conducted on incidents related to high-alert medications, ventilator associated pneumonia, catheter-related blood stream infection, urinary tract infection, and unwanted extubation...
May 9, 2016: International Journal of Health Care Quality Assurance
Assim Boukhayma, Antoine Dupret, Jean-Pierre Rostaing, Christian Enz
This paper presents the first low noise complementary metal oxide semiconductor (CMOS) deletedCMOS terahertz (THz) imager based on source modulation and in-pixel high-Q filtering. The 31 × 31 focal plane array has been fully integrated in a 0 . 13 μ m standard CMOS process. The sensitivity has been improved significantly by modulating the active THz source that lights the scene and performing on-chip high-Q filtering. Each pixel encompass a broadband bow tie antenna coupled to an N-type metal-oxide-semiconductor (NMOS) detector that shifts the THz radiation, a low noise adjustable gain amplifier and a high-Q filter centered at the modulation frequency...
2016: Sensors
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