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https://www.readbyqxmd.com/read/28227793/experimental-validation-of-neutron-activation-simulation-of-a-varian-medical-linear-accelerator
#1
S Morato, B Juste, R Miro, G Verdu, S Diez, S Morato, B Juste, R Miro, G Verdu, S Diez, B Juste, S Diez, R Miro, S Morato, G Verdu
This work presents a Monte Carlo simulation using the last version of MCNP, v. 6.1.1, of a Varian CLinAc emitting a 15MeV photon beam. The main objective of the work is to estimate the photoneutron production and activated products inside the medical linear accelerator head. To that, the Varian LinAc head was modelled in detail using the manufacturer information, and the model was generated with a CAD software and exported as a mesh to be included in the particle transport simulation. The model includes the transport of photoneutrons generated by primary photons and the (n, γ) reactions which can result in activation products...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28224987/towards-high-resolution-laser-ionization-spectroscopy-of-the-heaviest-elements-in-supersonic-gas-jet-expansion
#2
R Ferrer, A Barzakh, B Bastin, R Beerwerth, M Block, P Creemers, H Grawe, R de Groote, P Delahaye, X Fléchard, S Franchoo, S Fritzsche, L P Gaffney, L Ghys, W Gins, C Granados, R Heinke, L Hijazi, M Huyse, T Kron, Yu Kudryavtsev, M Laatiaoui, N Lecesne, M Loiselet, F Lutton, I D Moore, Y Martínez, E Mogilevskiy, P Naubereit, J Piot, S Raeder, S Rothe, H Savajols, S Sels, V Sonnenschein, J-C Thomas, E Traykov, C Van Beveren, P Van den Bergh, P Van Duppen, K Wendt, A Zadvornaya
Resonant laser ionization and spectroscopy are widely used techniques at radioactive ion beam facilities to produce pure beams of exotic nuclei and measure the shape, size, spin and electromagnetic multipole moments of these nuclei. However, in such measurements it is difficult to combine a high efficiency with a high spectral resolution. Here we demonstrate the on-line application of atomic laser ionization spectroscopy in a supersonic gas jet, a technique suited for high-precision studies of the ground- and isomeric-state properties of nuclei located at the extremes of stability...
February 22, 2017: Nature Communications
https://www.readbyqxmd.com/read/28211717/isomeric-character-of-the-lowest-observed-4-state-in-44-s
#3
J J Parker, I Wiedenhöver, P D Cottle, J Baker, D McPherson, M A Riley, D Santiago-Gonzalez, A Volya, V M Bader, T Baugher, D Bazin, A Gade, T Ginter, H Iwasaki, C Loelius, C Morse, F Recchia, D Smalley, S R Stroberg, K Whitmore, D Weisshaar, A Lemasson, H L Crawford, A O Macchiavelli, K Wimmer
Previous experiments observed a 4^{+} state in the N=28 nucleus ^{44}S and suggested that this state may exhibit a hindered E2-decay rate, inconsistent with being a member of the collective ground state band. We populate this state via two-proton knockout from a beam of exotic ^{46}Ar projectiles and measure its lifetime using the recoil distance method with the GRETINA γ-ray spectrometer. The result, 76(14)_{stat}(20)_{syst}  ps, implies a hindered transition of B(E2;4^{+}→2_{1}^{+})=0.61(19) single-particle or Weisskopf units strength and supports the interpretation of the 4^{+} state as a K=4 isomer, the first example of a high-K isomer in a nucleus of such low mass...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28209456/the-role-of-stereotactic-ablative-body-radiotherapy-in-gynaecological-cancers-a-systematic-review
#4
L C Mendez, E Leung, P Cheung, L Barbera
AIMS: To summarise and evaluate the current literature in gynaecological tumours treated with stereotactic ablative body radiotherapy (SABR) through a systematic review using the Preferred Reported Items for Systematic Reviews and Meta-analysis (PRISMA) guideline. MATERIALS AND METHODS: A literature search through Medline, EMBASE and Cochrane databases resulted in 22 pertinent manuscripts. Selected studies evaluated the locoregional role of SABR in gynaecological tumours, regardless of SABR clinical indication...
February 13, 2017: Clinical Oncology: a Journal of the Royal College of Radiologists
https://www.readbyqxmd.com/read/28203001/-effect-of-concentrated-growth-factors-on-the-treatment-of-degree-ii-furcation-involvements-of-mandibular-molars
#5
J Qiao, J Y Duan, Y Chu, C Z Sun
OBJECTIVE: Concentrated growth factors (CGF), a new generation of platelet concentrate products, appears to have more abundant growth factors because of its special centrifugation process. However, there are few studies supporting this. This study was designed to evaluate the effect of CGFs in the treatment of II° furcations of mandibular molars. METHODS: In the present study, thirty-one II° furcation involvements in twenty mandiblular molars were included and randomly divided into two groups...
February 18, 2017: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
https://www.readbyqxmd.com/read/28202212/long-term-patient-reported-urinary-function-following-external-beam-radiotherapy-for-prostate-cancer
#6
S Chin, A J Hayden, V Gebski, S Cross, S L Turner
INTRODUCTION: This study reports long-term patient reported urinary function and urinary-related quality of life (uQoL) after external beam radiotherapy (EBRT) for localized prostate cancer. METHODS: 574 men underwent definitive prostate EBRT to 70-78 Gy±androgen deprivation therapy between 2000 and 2009. The median follow-up from EBRT was 44 months. Patients were evaluated at baseline (pre-EBRT) and at intervals post-treatment using the International Prostate Symptom Score (IPSS) instrument...
February 12, 2017: Clinical Oncology: a Journal of the Royal College of Radiologists
https://www.readbyqxmd.com/read/28201899/the-electric-dipole-moments-in-the-ground-states-of-gold-oxide-auo-and-gold-sulfide-aus
#7
Ruohan Zhang, Yuanqin Yu, Timothy C Steimle, Lan Cheng
The B(2)Σ(-) - X(2)Π3/2(0,0) bands of a cold molecular beam sample of gold monoxide, AuO, and gold monosulfide, AuS, have been recorded at high resolution both field free and in the presence of a static electric field. The observed electric field induced splittings and shifts were analyzed to produce permanent electric dipole moments, μ→el, of 2.94±0.06 D and 2.22±0.05 D for the X(2)Π3/2(v = 0) states of AuO and AuS, respectively. A molecular orbital correlation diagram is used to rationalize the trend in ground state μ→el values for AuX (X = F, Cl, O, and S) molecules...
February 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28197824/in-vitro-cytotoxicity-and-surface-topography-evaluation-of-additive-manufacturing-titanium-implant-materials
#8
Jukka T Tuomi, Roy V Björkstrand, Mikael L Pernu, Mika V J Salmi, Eero I Huotilainen, Jan E H Wolff, Pekka K Vallittu, Antti A Mäkitie
Custom-designed patient-specific implants and reconstruction plates are to date commonly manufactured using two different additive manufacturing (AM) technologies: direct metal laser sintering (DMLS) and electron beam melting (EBM). The purpose of this investigation was to characterize the surface structure and to assess the cytotoxicity of titanium alloys processed using DMLS and EBM technologies as the existing information on these issues is scarce. "Processed" and "polished" DMLS and EBM disks were assessed...
March 2017: Journal of Materials Science. Materials in Medicine
https://www.readbyqxmd.com/read/28196288/clinical-adequacy-assessment-of-auto-contours-for-prostate-imrt-with-meaningful-endpoints
#9
Hamidreza Nourzadeh, William T Watkins, Mahmoud Ahmad, Cheukkai Hui, David Schlesinger, Jeffrey V Siebers
PURPOSE: To determine if radiation treatment plans created based on auto-segmented (AS) regions-of-interest (ROI)s are clinically equivalent to plans created based on manually segmented ROIs, where equivalence is evaluated using probabilistic dosimetric metrics and probabilistic biological endpoints for prostate IMRT. METHOD AND MATERIALS: Manually drawn contours and auto-segmented ROIs were created for 167 CT image sets acquired from 19 prostate patients. Auto-segmentation was performed utilizing Pinnacle's Smart Probabilistic Image Contouring Engine...
February 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/28195276/an-experimental-thermally-deposited-coating-for-improved-bonding-to-glass-fiber-posts
#10
Giselle Rodrigues Reis, Fernanda Pereira Silva, Aline Oliveira-Ogliari, André Luis Faria-E-Silva, Rafael R Moraes, Veridiana Resende Novais, Murilo de Sousa Menezes
PURPOSE: To determine whether an experimental thermally deposited siloxane-methacrylate coating for use in industrial scale applications would improve the bond strength of resin-based materials to glass fiber posts (GFPs) without affecting their mechanical properties. MATERIALS AND METHODS: An experimental 5% (w/v) solution of methacryloxypropyltrimethoxysilane was prepared. Two types of GFPs (Exacto, Angelus; White Post DC, FGM) were divided into the following groups: S: silane; SA: silane and adhesive; HS: 35% H₂O₂ and silane; HSA: 35% H₂O₂, silane and adhesive; Exp: siloxane-methacrylate coating (Si-O) via post immersion in experimental solution followed by heating; Exp-S: silane after Si-O treatment; Exp-A: adhesive after Si-O treatment; and Exp-SA: silane and adhesive after Si-O treatment...
February 10, 2017: Journal of Adhesive Dentistry
https://www.readbyqxmd.com/read/28191929/stop-frame-filming-and-discovery-of-reactions-at-the-single-molecule-level-by-transmission-electron-microscopy
#11
Thomas W Chamberlain, Johannes Biskupek, Stephen T Skowron, Alexander V Markevich, Simon Kurasch, Oliver Reimer, Kate Walker, Graham A Rance, Xinliang Feng, Klaus Müllen, Andrey Turchanin, Maria A Lebedeva, Alexander Majouga, Valentine Georgievich Nenajdenko, Ute Kaiser, Elena Besley, Andrei N Khlobystov
We report an approach - named chemTEM - to follow chemical transformations at the single-molecule level with the electron beam of a transmission electron microscope (TEM) applied as both a tuneable source of energy and a sub-Angstrom imaging probe. Deposited on graphene, disk-shaped perchlorocoronene molecules are precluded from intermolecular interactions. This allows monomolecular transformations to be studied at the single-molecule level in real time and reveals chlorine elimination and reactive aryne formation as a key initial stage of multi-step reactions initiated by the 80 keV e-beam...
February 13, 2017: ACS Nano
https://www.readbyqxmd.com/read/28191566/type-inversion-as-a-working-mechanism-of-high-voltage-mapbbr3-cl-based-halide-perovskite-solar-cells
#12
Nir Kedem, Michael Kulbak, Thomas M Brenner, Gary Hodes, David Cahen
Using several metals with different work functions as solar cell back contact we identify majority carrier type inversion in methylammonium lead bromide (MAPbBr3, without intentional doping) as the basis for the formation of a p-n junction. MAPbBr3 films deposited on TiO2 are slightly n-type, whereas in a full device they are strongly p-type. The charge transfer between the metal electrode and the halide perovskite (HaP) film is shown to determine the dominant charge carrier type of the HaP and, thus, also of the final cells...
February 13, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28181915/interlayer-vacancy-defects-in-aa-stacked-bilayer-graphene-density-functional-theory-predictions
#13
Amanda Vuong, Tom Trevethan, Christopher Latham, Chris Ewels, Doğan Erbahar, Patrick Briddon, Mark Rayson, Malcolm Heggie
AA-stacked graphite and closely related structures, where carbon atoms are located in registry in adjacent graphene layers, are a feature of graphitic systems including twisted and folded bilayer graphene, and turbostratic graphite. We present the results of <i>ab initio</i> density functional theory calculations performed to investigate the complexes that are formed from the binding of vacancy defects across neighbouring layers in AA-stacked bilayers. As with AB stacking, the carbon atoms surrounding lattice vacancies can form interlayer structures with sp<sup>2</sup> bonding that are lower in energy than in-plane reconstructions...
February 9, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28179930/root-canal-morphology-of-mandibular-canine-in-an-iranian-population-a-cbct-assessment
#14
Ali Soleymani, Nafiseh Namaryan, Ehsan Moudi, Ali Gholinia
INTRODUCTION: The present study was conducted to assess the morphology of mandibular canines using cone-beam computed tomography (CBCT) in a north Iranian population. METHODS AND MATERIALS: For the morphological assessment of mandibular canines, 150 CBCT images taken from patients for different reasons were used. The mandibular canines were examined in sagittal, coronal and axial dimensions. The canal pattern, number of roots/canals, the tooth length, the orientation of the roots and the position of the apical foramina were evaluated and the effect of gender on each variable was assessed...
2017: Iranian Endodontic Journal
https://www.readbyqxmd.com/read/28178323/non-invasive-evaluation-of-facial-crestal-bone-with-ultrasonography
#15
Hsun-Liang Chan, Khaled Sinjab, Ming-Pang Chung, Yi-Chen Chiang, Hom-Lay Wang, William V Giannobile, Oliver D Kripfgans
PURPOSE: Facial crestal bone level and dimension determine function and esthetics of dentition and dental implants. We have previously demonstrated that ultrasound can identify bony and soft tissue structures in the oral cavity. The aim of this study is to evaluate the accuracy of using ultrasound to measure facial crestal bone level and thickness. MATERIALS AND METHODS: A commercially available medical ultrasound scanner, paired with a 14 MHz imaging probe was used to scan dental and periodontal tissues at the mid-facial site of each tooth on 6 fresh cadavers...
2017: PloS One
https://www.readbyqxmd.com/read/28170351/observation-of-quantum-oscillations-in-fib-fabricated-nanowires-of-topological-insulator-bi2se3
#16
Biplab Bhattacharyya, Alka Sharma, V P S Awana, A K Srivastava, T D Senguttuvan, Sudhir Husale
In the last few years, research based on topological insulators (TIs) has been of great interest due to their intrinsic exotic fundamental properties and potential applications such as quantum computers or spintronics. The fabrication of TI nanodevices and the study of their transport properties has mostly focused on high quality crystalline nanowires or nanoribbons. Here, we report a robust approach to Bi2Se3 nanowire formation from deposited flakes using an ion beam milling method. Fabricated Bi2Se3 nanowire devices were employed to investigate the robustness of the topological surface state (TSS) to gallium ion doping and any deformation in the material due to the fabrication tools...
March 22, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28168338/radiation-exposure-to-the-patients-in-thoracic-and-lumbar-spine-fusion-using-a-new-intraoperative-cone-beam-computed-tomography-imaging-technique-a-preliminary-study
#17
Ludovic Kaminski, V Cordemans, O Cartiaux, M Van Cauter
PURPOSE: The goals of this paper are to assess the ionizing radiation exposure to the patients during thoracic and lumbar spinal fusion using a new intraoperative 3D imaging system and to evaluate the factors that could explain the variability in the observed doses. METHOD: We retrospectively reviewed 97 patients who underwent posterior instrumented thoracic and/or lumbar spinal fusion from December 2013 to November 2014. Primary data were the total dose area product (total DAP, Gy cm(2)) and total skin dose (total SD, mGy)...
February 6, 2017: European Spine Journal
https://www.readbyqxmd.com/read/28166057/proton-therapy-of-prostate-cancer-by-anterior-oblique-beams-implications-of-setup-and-anatomy-variations
#18
M Moteabbed, A Trofimov, G C Sharp, Y Wang, A L Zietman, J A Efstathiou, H-M Lu
Proton therapy of prostate by anterior beams could offer an attractive option for treating patients with hip prosthesis and limiting the high-dose exposure to the rectum. We investigated the impact of setup and anatomy variations on the anterior-oblique (AO) proton plan dose, and strategies to manage these effects via range verification and adaptive delivery. Ten patients treated by bilateral (BL) passive-scattering proton therapy (79.2 Gy in 44 fractions) who underwent weekly verification CT scans were selected...
March 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28162946/first-clinical-report-of-proton-beam-therapy-for-postoperative-radiotherapy-for-non-small-cell-lung-cancer
#19
Jill S Remick, Caitlin Schonewolf, Peter Gabriel, Abigail Doucette, William P Levin, John C Kucharczuk, Sunil Singhal, Taine T V Pechet, Ramesh Rengan, Charles B Simone, Abigail T Berman
BACKGROUND AND PURPOSE: The characteristic Bragg peak of proton beam therapy (PBT) allows for sparing normal tissues beyond the tumor volume that may allow for decreased toxicities associated with postoperative radiation therapy (PORT). Here we report the first institutional experience with proton therapy for PORT in patients with non-small-cell lung cancer (NSCLC) and assess early toxicities and outcomes. MATERIALS AND METHODS: We identified 61 consecutive patients treated from 2011 to 2014 who underwent PORT for locally advanced NSCLC for positive microscopic margins and/or positive N2 lymph nodes (stage III), with 27 patients receiving PBT and 34 receiving intensity-modulated radiation therapy (IMRT)...
January 5, 2017: Clinical Lung Cancer
https://www.readbyqxmd.com/read/28158119/development-of-a-compact-optical-absolute-frequency-reference-for-space-with-10-sup-15-sup-instability
#20
Thilo Schuldt, Klaus Döringshoff, Evgeny V Kovalchuk, Anja Keetman, Julia Pahl, Achim Peters, Claus Braxmaier
We report on a compact and ruggedized setup for laser frequency stabilization employing Doppler-free spectroscopy of molecular iodine near 532 nm. Using a 30 cm long iodine cell in a triple-pass configuration in combination with noise-canceling detection and residual amplitude modulation control, a frequency instability of 6×10<sup>-15</sup> at 1 s integration time and a Flicker noise floor below 3×10<sup>-15</sup> for integration times between 100 and 1000 s was found. A specific assembly-integration technology was applied for the realization of the spectroscopy setup, ensuring high beam pointing stability and high thermal and mechanical rigidity...
February 1, 2017: Applied Optics
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