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Chan Park, Mong-Sook Vang, Sang-Won Park, Hyun-Pil Lim
STATEMENT OF PROBLEM: Although many systems are used to polish zirconia, a comparison of the performance of zirconia and feldspathic porcelain polishing systems is lacking. PURPOSE: The purpose of this in vitro study was to compare the effects of 3 polishing systems on surface roughness, zirconia phase transformation, and durability of the polishing systems when applied to zirconia and feldspathic porcelain. MATERIAL AND METHODS: Three polishing systems were evaluated: Z1, a zirconia polishing system; Z2, a zirconia polishing system, and F1, a feldspathic porcelain polishing system...
January 11, 2017: Journal of Prosthetic Dentistry
Alberto Villarrubia, Enrique García, Antonio Cano-Ortiz, Alberto Membrillo, Antoni Sabala, Javier Celis, Antoni Salvador, Jorge Solana, Alexandra Arango, Irene Sassot
PURPOSE: To analyze differences in the stromal bed according to the method used to obtain the disc for endothelial transplant with 1) an automated microkeratome for Descemet stripping automated endothelial keratoplasty (DSAEK), 2) homogeneous dissection of Descemet membrane (Descemet membrane endothelial keratoplasty [DMEK]), or 3) a manual microkeratome used for DSAEK. METHODS: We analyzed the stromal bed of 25 consecutive corneas used for endothelial transplantation, divided into 3 groups: 1) 11 samples cut with an automated microkeratome, 2) 5 samples used for DMEK, 3) 9 samples cut with a manual microkeratome...
January 11, 2017: Cornea
Matthias Muenks, Peter Jacobson, Markus Ternes, Klaus Kern
Spin-spin correlations can be the driving force that favours certain ground states and are key in numerous models that describe the behaviour of strongly correlated materials. While the sum of collective correlations usually lead to a macroscopically measurable change in properties, a direct quantification of correlations in atomic scale systems is difficult. Here we determine the correlations between a strongly hybridized spin impurity on the tip of a scanning tunnelling microscope and its electron bath by varying the coupling to a second spin impurity weakly hybridized to the sample surface...
January 11, 2017: Nature Communications
David Breuskin, Jacek Szczygielski, Steffi Urbschat, Yoo-Jin Kim, Joachim Oertel
INTRODUCTION: Intraoperative distinction of brain tumor from the surround brain is one of the crucial challenges in neurooncological surgery. In this study, confocal laser endomicroscope (CLE) findings were directly compared with intraoperative instantaneous sections by the neuropathologist in a blinded fashion. MATERIAL AND METHODS: The imaging device comprises of a rigid endoscope with Hopkins-Rod lenses and a red wave length laser with a scanning depth of 80 μm...
January 6, 2017: World Neurosurgery
Louis P Ronse De Craene
BACKGROUND AND AIMS: Berberidopsis beckleri is one of three species of the family Berberidopsidaceae. The flower of Berberidopsis is unusual for core eudicots in being spiral with an undifferentiated perianth. In a previous study of the sister species B. corallina, it was suggested that Berberidopsidaceae represent a prototype for the origin of the bipartite perianth and pentamery in core eudicots. METHODS: The floral development of B. beckleri was investigated with a scanning electron microscope and compared with previous studies on B...
January 8, 2017: Annals of Botany
N A Sanford, P T Blanchard, R White, M R Vissers, D R Diercks, A V Davydov, D P Pappas
Laser-assisted atom probe tomography (L-APT) was used to examine superconducting TiN/Ti/TiN trilayer films with nominal respective thicknesses of 5/5/5 (nm). Such materials are of interest for applications that require large arrays of microwave kinetic inductance detectors. The trilayers were deposited on Si substrates by reactive sputtering. Electron energy loss microscopy performed in a scanning transmission electron microscope (STEM/EELS) was used to corroborate the L-APT results and establish the overall thicknesses of the trilayers...
December 21, 2016: Micron: the International Research and Review Journal for Microscopy
Bastian Bier, Martin Berger, Andreas Maier, Marc Kachelrieß, Ludwig Ritschl, Kerstin Műller, Jang-Hwan Choi, Rebecca Fahrig
PURPOSE: Cone-beam computed tomography (CBCT) suffers from a large amount of scatter, resulting in severe scatter artifacts in the reconstructions. Recently, a new scatter correction approach, called improved primary modulator scatter estimation (iPMSE), was introduced. That approach utilizes a primary modulator that is inserted between the X-ray source and the object. This modulation enables estimation of the scatter in the projection domain by optimizing an objective function with respect to the scatter estimate...
January 6, 2017: Medical Physics
Antonio Martínez-Galera, Zheng Wei, Nicoleta Nicoara, Ivan Brihuega, Jose M Gomez-Rodriguez
The initial stages of growth of PTCDA (3,4,9,10 perylene tetracarboxylic dianhydride) at room temperature (RT) on Ge(111)-c(2x8) surfaces have been studied by means of scanning tunneling microscopy (STM) under ultrahigh vacuum conditions. The results show that PTCDA molecules have a high mobility at RT on the well ordered areas of the semiconductor substrate, since nucleation is only observed in domain walls, steps and surface defects. However, no molecular ordering has been detected at submonolayer coverage...
January 6, 2017: Nanotechnology
Marc Benjamin Hahn, Susann Meyer, Maria-Astrid Schröter, Harald Seitz, Hans-Jörg Kunte, Tihomir Solomun, Heinz Sturm
We report on a study in which plasmid DNA in water was irradiated with 30 keV electrons generated by a scanning electron microscope and passed through a 100 nm thick Si3N4 membrane. The corresponding Monte Carlo simulations suggest that the kinetic energy spectrum of the electrons throughout the water is dominated by low energy electrons (<100 eV). The DNA radiation damage, single-strand breaks (SSBs) and double-strand breaks (DSBs), was determined by gel electrophoresis. The median lethal dose of D1/2 = 1...
January 6, 2017: Physical Chemistry Chemical Physics: PCCP
Maria Vittoria Cicinelli, Alessandro Rabiolo, Alessandro Marchese, Luigi de Vitis, Adriano Carnevali, Lea Querques, Francesco Bandello, Giuseppe Querques
AIMS: To describe the vascular changes in patients affected by non-neovascular age-related macular degeneration (AMD), featuring reticular pseudodrusen (RPD), drusen, or both RPD and drusen by means of optical coherence tomography angiography (OCT-A). METHODS: Cross-sectional observational case series. Patients with non-neovascular AMD presenting at the Medical Retina Service of the Department of Ophthalmology, University Vita-Salute San Raffaele in Milan were recruited...
January 5, 2017: British Journal of Ophthalmology
Yimin Zhong, Xinxing Guo, Hui Xiao, Jingyi Luo, Chengguo Zuo, Xiaobo Huang, Jingjing Huang, Lan Mi, Qingjiong Zhang, Xing Liu
PURPOSE: Trabeculectomy has been regarded as a mainstay of initial treatment in eyes of angle closure glaucoma (ACG) with peripheral anterior synechia > 180° in the Chinese population while its efficacy in secondary ACG with BEST1 gene mutation remains unclear. We set out to investigate the treatment outcome of trabeculectomy for secondary ACG in a group of patients with autosomal recessive bestrophinopathy (ARB). METHODS: In this retrospective case series study, 8 secondary ACG patients with ARB and their 4 recruited family members underwent a thorough ophthalmic examination including best-corrected visual acuity, Goldmann applanation tonometry, gonioscopy, and fundus examinations...
2017: PloS One
Lu Zhang, Derek DeArmond, Noe T Alvarez, Rachit Malik, Nicholas Oslin, Colin McConnell, Paa Kwasi Adusei, Yu-Yun Hsieh, Vesselin Shanov
Flexible micro-supercapacitors (MSCs) are constructed by 3D graphene from chemical vapor deposition. Without using any binder or metal current collector, the as-prepared 3D graphene MSC exhibits good flexibility, excellent cyclic life, and high areal capacitance of 1.5 mF cm(-2) at a scan rate of 10 V s(-1) . The electrochemical performance is further improved by oxygen plasma functionalization.
January 5, 2017: Small
L Cervino, D Soultan, N Pettersson, A Yock, M Cornell, J Aguilera, J Murphy, B Gill, S Advani, V Moiseenko
PURPOSE: to evaluate the dosimetric and radiobiological consequences from having different gating windows, dose rates, and breathing patterns in gated VMAT lung radiotherapy. METHODS: A novel 3D-printed moving phantom with central high and peripheral low tracer uptake regions was 4D FDG-PET/CT-scanned using ideal, patient-specific regular, and irregular breathing patterns. A scan of the stationary phantom was obtained as a reference. Target volumes corresponding to different uptake regions were delineated...
June 2016: Medical Physics
S Deshpande, D Dhote, S Naidu, A Sutar, V Kannan
PURPOSE: To study effect of scan length on magnitude of imaging dose deposition in Varian kV CBCT for head & neck and pelvis CBCT. METHODS: To study effect of scan length we measured imaging dose at depth of 8 cm for head and neck Cone Beam Computed Tomography (CBCT) acquisition (X ray beam energy is used 100kV and 200 degree of gantry rotation) and at 16 cm depth for pelvis CBCT acquisition (X ray beam energy used is 125 kV and 360 degree of gantry rotation) in specially designed phantom...
June 2016: Medical Physics
T McCaw, M Hwang, S Jang, M Huq
PURPOSE: To quantify differences between the TG51 and TG51 addendum calibration protocols. METHODS: Beam energies of 6X, 6XSRS, 10X, 15X, 23X, 6XFFF, and 10XFFF were calibrated following both the TG51 and TG51 addendum protocols using both a Farmer and a scanning ionization chamber with traceable absorbed dose-to-water calibrations. For the TG51 addendum procedure, the collimating jaws were positioned to define a 10×10cm(2) radiation field, a lead foil was only used for kQ measurements of FFF energies, and a volume-averaging correction was applied based on crossline and inline dose profiles...
June 2016: Medical Physics
T Matsuura, S Takao, Y Matsuzaki, Y Fujii, T Fujii, K Maeda, H Ueda, H Koyano, K Umegaki, H Shirato
PURPOSE: To reduce the lateral penumbra of low-energy proton beams, brass collimators are often used in spot-scanning proton therapy (SSPT). This study investigates the increase in biological effectiveness through collimator scattered protons in SSPT. METHODS: The SSPT system of the Hokkaido University Hospital Proton Beam Therapy Center, which consists of a scanning nozzle, a 2-cm thick brass collimator, and a 4-cm thick energy absorber, was simulated with our validated Geant4 Monte Carlo code (ver...
June 2016: Medical Physics
B Wears, I Mohiuddin, R Flynn, T Waldron, Y Kim, B Allen, J Xia
PURPOSE: Developing a compact collimator system and validating a 3D surface imaging module for a scanning beam low-energy x-ray radiation therapy (SBIORT) system that enables delivery of non-uniform radiation dose to targets with irregular shapes intraoperatively. METHODS: SBIORT consists of a low energy x-ray source, a custom compact collimator module, a robotic arm, and a 3D surface imaging module. The 3D surface imaging system (structure sensor) is utilized for treatment planning and motion monitoring of the surgical cavity...
June 2016: Medical Physics
X Ding, X Li, J Zhang, P Kabolizadeh, C Stevens, D Yan
PURPOSE: To develop a delivery-efficient proton spot-scanning arc therapy technique with robust plan quality. METHODS: We developed a Scanning Proton Arc(SPArc) optimization algorithm integrated with (1)Control point re-sampling by splitting control point into adjacent sub-control points; (2)Energy layer re-distribution by assigning the original energy layers to the new sub-control points; (3)Energy layer filtration by deleting low MU weighting energy layers; (4)Energy layer re-sampling by sampling additional layers to ensure the optimal solution...
June 2016: Medical Physics
J M Slagowski, Dap Dunkerley
PURPOSE: To obtain ECG-gated CT images from truncated projection data acquired with a C-arm based inverse geometry fluoroscopy system, for the purpose of cardiac chamber mapping in interventional procedures. METHODS: Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system with a scanned multisource x-ray tube and a photon-counting detector mounted to a C-arm. In the proposed method, SBDX short-scan rotational acquisition is performed followed by inverse geometry CT (IGCT) reconstruction and segmentation of contrast-enhanced objects...
June 2016: Medical Physics
S Lee, D Markel, G Hegyi, I El Naqa
PURPOSE: The reliability of computed tomography (CT) textures is an important element of radiomics analysis. This study investigates the dependency of lung CT textures on different breathing phases and changes in CT image acquisition protocols in a realistic phantom setting. METHODS: We investigated 11 CT texture features for radiation-induced lung disease from 3 categories (first-order, grey level co-ocurrence matrix (GLCM), and Law's filter). A biomechanical swine lung phantom was scanned at two breathing phases (inhale/exhale) and two scanning protocols set for PET/CT and diagnostic CT scanning...
June 2016: Medical Physics
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