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Martin Hartmann, Cornelius Dirk, Susanne Reimann, Ludger Keilig, Anna Konermann, Andreas Jäger, Christoph Bourauel
AIMS: The goal was to determine the influence of different geometric parameters of the tooth on the initial tooth mobility and the position of the center of resistance employing numerical models based on scaled X-ray images and plaster casts. METHODS: The dimensions of tooth 21 were measured in 21 patients, using radiographs and dental casts. Length and mesiodistal width of the tooth were obtained from the X-ray image and the orovestibular diameter from the plaster cast...
January 13, 2017: Journal of Orofacial Orthopedics, Fortschritte der Kieferorthopädie
Manaswee Suttipong, Brian P Grady, Alberto Striolo
Using coarse-grained dissipative particle dynamics (DPD) simulations, we systematically study the effect of surface heterogeneity on surfactant adsorption. Here we investigate the adsorption and aggregation of surfactants on hydrophobic stripes crossing each other perpendicularly (i.e., crossing stripes) and on hydrophobic steps. The results are compared with those obtained for isolated stripes. We find that on crossing stripes of moderate stripe widths (e.g., L = 0.61LS, 1.22LS and 1.83LS, where LS is the length of one surfactant molecule) the crossing region hinders the formation of defect-free adsorbed surfactant structures...
January 11, 2017: Soft Matter
Matthias B Jungfleisch, Junjia Ding, Wei Zhang, Wanjun Jiang, John E Pearson, Valentine Novosad, Axel Hoffmann
Magnetic insulators, such as yttrium iron garnet (Y3Fe5O12), are ideal materials for ultralow power spintronics applications due to their low energy dissipation and efficient spin current generation and transmission. Recently, it has been realized that spin dynamics can be driven very effectively in micrometer-sized Y3Fe5O12/Pt heterostructures by spin-Hall effects. We demonstrate here the excitation and detection of spin dynamics in Y3Fe5O12/Pt nanowires by spin-torque ferromagnetic resonance. The nanowires defined via electron-beam lithography are fabricated by conventional room temperature sputtering deposition on Gd3Ga5O12 substrates and lift-off...
January 11, 2017: Nano Letters
Joshua Vickers, Austin Reed, Robert Decker, Bryan P Conrad, Marissa Olegario-Nebel, Heather K Vincent
Despite the ubiquity of gait assessment in clinic and research, it is unclear how observation impacts gait, particularly in persons with chronic pain and psychological stress. We compared temporal spatial gait patterns in people with and without chronic low back pain (CLBP) when they were aware and unaware of being observed. This was a repeated-measures, deception study in 55 healthy persons (32.0±12.4 yr, 24.2±2.7kg/m(2)) and persons with CLBP (51.9±17.9 yr, 27.8±4.4kg/m(2)). Participants performed one condition in which they were unaware of observation (UNW), and three conditions under investigator observation: (1) aware of observation (AWA), (2) investigators watching cadence, (3) investigators watching step length...
January 3, 2017: Gait & Posture
Qi-Xing Ou, Marija Nikolic-Jaric, Michael Gänzle
AIMS: This study aimed to determine how electric field strength, pulse width and shape, and specific energy input relate to the effect of pulsed electric fields (PEF) on viability and membrane permeabilization in Candida humilis and Saccharomyces cerevisiae suspended in potassium phosphate buffer. METHODS AND RESULTS: Cells were treated with a micro-scale system with parallel plate electrodes. Propidium iodide was added before or after treatments to differentiate between reversible and irreversible membrane permeabilization...
December 30, 2016: Bioelectrochemistry
R O'Brien, U Stankovic, P Keall, J Sonke
PURPOSE: We have developed a method, called respiratory motion guided 4DCBCT (RMG-4DCBCT), in which the gantry speed and projection frequency are varied in response to the patient's real-time respiratory signal to eliminate streaking artifacts and to suppress duplicate projections in 4DCBCT images. In 2015, we realized RMG-4DCBCT on an Elekta Synergy linear accelerator with a mechanical relay to suppress projections and a potentiometer to adjust the gantry speed in response to the patient's real-time respiratory signal...
June 2016: Medical Physics
A Almonte, G Polanco, E Sanchez
PURPOSE: The aim of the present contribution was to measure the main dosimetric quantities of small fields produced by UNIQUE and evaluate its matching with the corresponding dosimetric data of one 21EX conventional linear accelerator (Varian) in operation at the same center. The second step was to evaluate comparative performance of the EDGE diode detector and the PinPoint micro-ionization chamber for dosimetry of small fields. METHODS: UNIQUE is configured with MLC (120 leaves with 0...
June 2016: Medical Physics
L Yang, D O'Connell, P Lee, N Shaverdian, A Kishan, J Lewis, T Dou, D Thomas, X Qi, D Low
PURPOSE: A published 5DCT breathing motion model enables image reconstruction at any user-selected breathing phase, defined by the model as a specific amplitude (v) and rate (f). Generation of reconstructed phase-specific CT scans will be required for time-independent radiation dose distribution simulations. This work answers the question: how many amplitude and rate bins are required to describe the tumor motion with a specific spatial resolution? METHODS: 19 lung-cancer patients with 21 tumors were scanned using a free-breathing 5DCT protocol, employing an abdominally positioned pneumatic-bellows breathing surrogate and yielding voxel-specific motion model parameters α and β corresponding to motion as a function of amplitude and rate, respectively...
June 2016: Medical Physics
T Chiu, B Yang, M Law, W Lam, C Kong, H Geng, K Cheung, S Yu
PURPOSE: To investigate the appropriateness of Gaussian detector response function in SRS profile measurement. METHODS: In-air profile data for a 6MV beam were collected by using ionization chambers and radiochromic film. Two ionization chambers (FC65-G(IBA) and PinPoint(PTWTW31009)) were used to scan the beam profile. Film was used to measure the beam penumbra. A half-blocked beam was acquired with stepping size of 0.2mm and gradient of the measured profile represents the detector response function...
June 2016: Medical Physics
D Han, H Safigholi, A Soliman, W Song
PURPOSE: To explore and quantify the upper limits in dose sculpting capacity of the novel direction modulated brachytherapy (DMBT) tandem applicator compared with conventional tandem design for (192) Ir-based HDR planning. METHODS: The proposed DMBT tandem applicator is designed for image-guided adaptive brachytherapy (IGABT), especially MRI, of cervical cancer. It has 6 peripheral holes of 1.3-mm width, grooved along a 5.4-mm diameter nonmagnetic tungsten alloy rod of density 18...
June 2016: Medical Physics
E D Morris, P Klahr, C Glide-Hurst
PURPOSE: To sample the breathing cycle and obtain accurate target volumes, 4DCT requires the entire field of view (FOV) to be illuminated during one breathing period. However, interplay effects between internal motion and couch pitch may adversely impact the temporal resolution, thereby blurring object edges. This work performs a characterization of exponential 4DCT reconstruction to highlight potential gains over standard cos2 weighted reconstruction algorithm. METHODS: A respiratory motion platform translated several objects in the superior-inferior direction at varied breathing rates (8-20 breaths/minute) and couch pitches (0...
June 2016: Medical Physics
S Zhou, Q Wu, Q Fan, Y Lei, S Li, X Li, R Ma, S Wang, X Wang, D Zheng, X Zhu, C Enke
PURPOSE: In-Water-Output-Ratio (IWOR) plays a significant role in linac-based radiotherapy treatment planning, linking MUs to delivered radiation dose. For an open rectangular field, IWOR depends on both its width and length, and changes rapidly when one of them becomes small. In this study, a universal functional form is proposed to fit the open field IWOR tables in Varian TrueBeam representative datasets for all photon energies. METHODS: A novel Generalized Mean formula is first used to estimate the Equivalent Square (ES) for a rectangular field...
June 2016: Medical Physics
Alexey Ognev, Konstantin Ermakov, Aleksei Samardak, Ekaterina Sukovatitsina, Aleksey Kozlov, Aleksandr Davydenko, Ludmila Chebotkevich, Alexandru Stancu, Alexander S Samardak
Further development of microelectronics requires novel or improved technological approaches for a device nanofabrication and a functional properties characterization. In this paper we studied the crystal structure and magnetic properties of epitaxial Co nanostrips of the average width of 32.6, 45.3 and 62.6 nm grown on the step-bunched Si(111)5.55×5.55-Cu/Cu surface. Technological conditions, under which the ultra-high aspect ratio (∼10<sup>4</sup>) structurally solid, straight nanostrips of hcp-Co with crystallographic axis [0001] oriented along their long side can be grown, were determined...
January 3, 2017: Nanotechnology
Nataliya Shishov, Yoav Gimmon, Hisham Rashed, Ilan Kurz, Raziel Riemer, Amir Shapiro, Ronen Debi, Itshak Melzer
Specific patterns of pelvic and thorax motions are required to maintain stability during walking. This cross-sectional study explored older-adults' gait kinematics and their kinematic adaptations to different walking speeds, with the purpose of identifying mechanisms that might be related to increased risk for falls. Fifty-eight older adults from self-care residential facilities walked on a treadmill, whose velocity was systematically increased with increments of 0.1meters/second (m/s) from 0.5 to 0.9m/s, and then similarly decreased...
December 5, 2016: Gait & Posture
A Fatima, S Kataria, L Baghel, K N Guruprasad, A K Agrawal, B Singh, P S Sarkar, T Shripathi, Y Kashyap
Experiments were conducted to study the effects of static magnetic fields (SMFs) on the venation network of soybean leaves using the synchrotron-based X-ray micro-imaging technique. The seeds of soybean (Glycine max, variety JS-335) were pretreated with different SMFs from 50 to 300 mT in steps of 50 mT for 1 h. The phase-contrast images obtained showed that, as the strength of the SMF increased, the area, width of the midrib, area of the midrib and minor vein of the middle leaflets of third trifoliate leaves also increased up to the SMF strength of 200 mT (1 h) and decreased thereafter...
January 1, 2017: Journal of Synchrotron Radiation
Selina L S Storm, Fabio Dall'Antonia, Gleb Bourenkov, Thomas R Schneider
High-quality high-multiplicity X-ray diffraction data were collected on five different crystals of thaumatin using a homogeneous-profile X-ray beam at E = 8 keV to investigate the counteracting effects of increased multiplicity and increased radiation damage on the quality of anomalous diffraction data collected on macromolecular crystals. By comparing sulfur substructures obtained from subsets of the data selected as a function of absorbed X-ray dose with sulfur positions in the respective refined reference structures, the doses at which the highest quality of anomalous differences could be obtained were identified for the five crystals...
January 1, 2017: Journal of Synchrotron Radiation
William Johnston, Matthew Patterson, Niamh O'Mahony, Brian Caulfield
Gait assessment is frequently used as an outcome measure to determine changes in an individual's mobility and disease processes. Inertial measurement units (IMUs) are quickly becoming commonplace in gait analysis. The purpose of this study was to determine and compare the validity of shank and lumbar IMU mounting locations in the estimation of temporal gait features. Thirty-seven adults performed 20 walking trials each over a gold standard force platform while wearing shank and lumbar-mounted IMUs. Data from the IMUs were used to estimate step times using previously published algorithms and were compared with those derived from the force platform...
December 21, 2016: Biomedizinische Technik. Biomedical Engineering
Jeong-Whan Son, Min Sun Lee, Jae Sung Lee
Positron emission tomography (PET) detectors with the ability to encode depth-of-interaction (DOI) information allow us to simultaneously improve the spatial resolution and sensitivity of PET scanners. In this study, we propose a DOI PET detector based on a stair-pattern reflector arrangement inserted between pixelated crystals and a single-ended scintillation light readout. The main advantage of the proposed method is its simplicity; DOI information is decoded from a flood map and the data can be simply acquired by using a single-ended readout system...
December 21, 2016: Physics in Medicine and Biology
Mohammad Humood, Shuang Qin, Yixuan Song, Kyriaki Polychronopoulou, Youfeng Zhang, Jaime C Grunlan, Andreas A Polycarpou
Graphene is a versatile composite reinforcement candidate due to its strong mechanical, tunable electrical and optical properties, and chemical stability. However, one drawback is the weak interfacial bonding, which results in weak adhesion to substrates. This could be overcome by adding polymer layers to have stronger adherence to the substrate and between graphene sheets. These multilayer thin films were found to have lower resistance to lateral scratch forces when compared to other reinforcements such as polymer/clay nanocomposites...
December 19, 2016: ACS Applied Materials & Interfaces
Shachi Tyagi, Subashan Perera, Jennifer S Brach
OBJECTIVES: To examine the effect of self-reported daytime sleepiness on performance-based balance measures and self-reported balance confidence in community-dwelling older adults. DESIGN: Cross-sectional secondary analysis of an observational cohort study designed to develop and refine measures of balance and mobility in community-dwelling older adults. SETTING: Community. PARTICIPANTS: Older adults (aged 78.2 ± 5...
December 19, 2016: Journal of the American Geriatrics Society
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