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Dudu Tong, Sichun Yang, Lanyuan Lu
Structure modelling via small-angle X-ray scattering (SAXS) data generally requires intensive computations of scattering intensity from any given biomolecular structure, where the accurate evaluation of SAXS profiles using coarse-grained (CG) methods is vital to improve computational efficiency. To date, most CG SAXS computing methods have been based on a single-bead-per-residue approximation but have neglected structural correlations between amino acids. To improve the accuracy of scattering calculations, accurate CG form factors of amino acids are now derived using a rigorous optimization strategy, termed electron-density matching (EDM), to best fit electron-density distributions of protein structures...
August 1, 2016: Journal of Applied Crystallography
Sebastian Vellmer, Rüdiger Stirnberg, Daniel Edelhoff, Dieter Suter, Tony Stöcker, Ivan I Maximov
Visualisation of living tissue structure and function is a challenging problem of modern imaging techniques. Diffusion MRI allows one to probe in vivo structures on a micrometer scale. However, conventional diffusion measurements are time-consuming procedures, because they require several measurements with different gradient directions. Considerable time savings are therefore possible by measurement schemes that generate an isotropic diffusion weighting in a single shot. Multiple approaches for generating isotropic diffusion weighting are known and have become very popular as useful tools in clinical research...
December 30, 2016: Journal of Magnetic Resonance
S A Shojaee, Y Qi, Y Q Wang, A Mehner, D A Lucca
Ion irradiation is an alternative to heat treatment for transforming organic-inorganic thin films to a ceramic state. One major shortcoming in previous studies of ion-irradiated films is the assumption that constituent phases in ion-irradiated and heat-treated films are identical and that the ion irradiation effect is limited to changes in composition. In this study, we investigate the effects of ion irradiation on both the composition and structure of constituent phases and use the results to explain the measured elastic modulus of the films...
January 10, 2017: Scientific Reports
Aurel Radulescu, Noemi Kinga Szekely, Marie-Sousai Appavou, Vitaliy Pipich, Thomas Kohnke, Vladimir Ossovyi, Simon Staringer, Gerald J Schneider, Matthias Amann, Bo Zhang-Haagen, Georg Brandl, Matthias Drochner, Ralf Engels, Romuald Hanslik, Günter Kemmerling
The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to µm. The instrument is optimized for the exploration of the wide momentum transfer Q range between 1x10(-4) and 0.5 Å(-1) by combining classical pinhole, focusing (with lenses), and time-of-flight (with chopper) methods, while simultaneously providing high-neutron intensities with an adjustable resolution. Because of its ability to adjust the intensity and the resolution within wide limits during the experiment, combined with the possibility to equip specific sample environments and ancillary devices, the KWS-2 shows a high versatility in addressing the broad range of structural and morphological studies in the field...
December 8, 2016: Journal of Visualized Experiments: JoVE
Q F Shen, T T Xu, Y P Xia
Objective: To compare the outcomes between anterior cervical discectomy and fusion (ACDF) and posterior laminectomy and fusion(LF) for multilevel cervical spondylotic myelopathy combined with cervical kyphosis. Methods: From January 2010 to June 2014, 54 patients with cervical spondylotic myelopathy combined with cervical kyphosis underwent surgical treatment.Among them, 29 patients were underwent ACDF, and 25 patients were underwent LF in Department of spine surgery, Tianjin Union Medical Centre. The operation time, intraoperative blood loss, fusion segments, Japanese Orthopaedic Association (JOA)score, Neck Disability Index (NDI), Visual Analog Scale (VAS), change of cervical curvature, range of motion(ROM)and complications were recorded and compared between the two groups...
December 20, 2016: Zhonghua Yi Xue za Zhi [Chinese medical journal]
Y Zhu, J J Zheng, F Yang, Q Q Nie, Z L Zhu, H Deng
Objective: To study CD10 expression in cancer-associated fibroblasts (CAF) and related effect on colorectal cancer initiation and progression. Methods: A total of 226 surgical removed colorectal cancer specimens were collected with patient follow-up data. A panel of immunohistochemical markers(CD10, Ki-67, p53, cyclin D1 and β-catenin) were evaluated in carcinomas, adjacent adenomas and paired normal colorectal mucosa with correlation of clinicopathological parameters. Results: CD10 expression was not detected in the normal colorectal mucosa by immunohistochemistry...
December 8, 2016: Zhonghua Bing Li Xue za Zhi Chinese Journal of Pathology
Alexander Yu Cherny, Eugen M Anitas, Vladimir A Osipov, Alexander I Kuklin
The small-angle scattering (SAS) from the Cantor surface fractal on the plane and Koch snowflake is considered. We develop the construction algorithm for the Koch snowflake, which makes possible the recurrence relation for the scattering amplitude. The surface fractals can be decomposed into a sum of surface mass fractals for arbitrary fractal iteration, which enables various approximations for the scattering intensity. It is shown that for the Cantor fractal, one can neglect with good accuracy the correlations between the mass fractal amplitudes, while for the Koch snowflake, these correlations are important...
January 5, 2017: Physical Chemistry Chemical Physics: PCCP
M L Jin, F Sun, L Y Xing, S J Zhang, S M Feng, P P Kong, W M Li, X C Wang, J L Zhu, Y W Long, H Y Bai, C Z Gu, R C Yu, W G Yang, G Y Shen, Y S Zhao, H K Mao, C Q Jin
Strong spin orbital interaction (SOI) can induce unique quantum phenomena such as topological insulators, the Rashba effect, or p-wave superconductivity. Combining these three quantum phenomena into a single compound has important scientific implications. Here we report experimental observations of consecutive quantum phase transitions from a Rashba type topological trivial phase to topological insulator state then further proceeding to superconductivity in a SOI compound BiTeI tuned via pressures. The electrical resistivity measurement with V shape change signals the transition from a Rashba type topological trivial to a topological insulator phase at 2 GPa, which is caused by an energy gap close then reopen with band inverse...
January 4, 2017: Scientific Reports
J Zhang, X Li, G Liu, Q Liu, J Liang, X Ding
PURPOSE: We compare and investigate the dosimetric impacts on pencil beam scanning (PBS) proton treatment plans generated with CT calibration curves from four different CT scanners and one averaged 'global' CT calibration curve. METHODS: The four CT scanners are located at three different hospital locations within the same health system. CT density calibration curves were collected from these scanners using the same CT calibration phantom and acquisition parameters...
June 2016: Medical Physics
M Hoff, J Andre, Q Xiang
PURPOSE: In addition to correcting magnetic field inhomogeneity-induced banding artifacts in balanced steady state free precession (bSSFP) MRI, preliminary in vivo studies indicate that the geometric solution (GS) also mitigates motion artifacts. The purpose here is to investigate the source of motion artifact correction through simulations, to further ascertain GS-bSSFP's clinical potential. METHODS: Four bSSFP MR images with Δθ = 0°, 90°, 180°, and 270° respective phase cycling and TE/TR = 4...
June 2016: Medical Physics
W Zhu, Q Wu, L Yuan
PURPOSE: To improve the robustness of a knowledge based automatic lung IMRT planning method and to further validate the reliability of this algorithm by utilizing for the planning of clinical cases with non-coplanar beams. METHODS: A lung IMRT planning method which automatically determines both plan optimization objectives and beam configurations with non-coplanar beams has been reported previously. A beam efficiency index map is constructed to guide beam angle selection in this algorithm...
June 2016: Medical Physics
Q Chen, P Read
PURPOSE: Multiple error pathways can lead to delivery errors during the treatment course that cannot be caught with pre-treatment QA. While in vivo solutions are being developed for linacs, no such solution exists for tomotherapy. The purpose of this study is to develop a near real-time system for tomotherapy that can monitor the delivery and dose accumulation process during the treatment-delivery, which enable the user to assess the impact of delivery variations and/or errors and to interrupt the treatment if necessary...
June 2016: Medical Physics
Q Wu, J Adamson, B Liang, B Liu, F Zhou
PURPOSE: For multiple mets radiosurgery, it is advantageous to use VMAT with a single isocenter for the ease in planning and efficiency in delivery. Insightful pre-treatment QA for these cases is difficult to obtain because (1) target size is often small and the same order of magnitude as the detector size for commercial array based VMAT pre-treatment QA devices; and furthermore (2) targets are located away from central axis where the array detectors are located. In this study, we present and validate an in-house developed VMAT QA technique that is capable of addressing these challenges...
June 2016: Medical Physics
A Syed Mohd, S Pütter, S Mattauch, A Koutsioubas, H Schneider, A Weber, T Brückel
We report on a versatile mini ultra-high vacuum (UHV) chamber which is designed to be used on the MAgnetic Reflectometer with high Incident Angle of the Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum in Garching, Germany. Samples are prepared in the adjacent thin film laboratory by molecular beam epitaxy and moved into the compact chamber for transfer without exposure to ambient air. The chamber is based on DN 40 CF flanges and equipped with sapphire view ports, a small getter pump, and a wobble stick, which serves also as sample holder...
December 2016: Review of Scientific Instruments
Spela Stunf Pukl, Brigita Drnovšek-Olup
PURPOSE: To evaluate the efficacy of selective laser trabeculoplasty (SLT) to lower intraocular pressure (IOP) in patients with primary open-angle glaucoma (POAG), normal tension glaucoma (NTG) or ocular hypertension (OHT), when performed with laser pulse duration of 1 ns compared with standard 3-5 ns. METHODS: Bilateral SLT with a 532 nm Q-switched neodymium-doped yttrium aluminium garnet laser was conducted in 30 patients (60 eyes) with POAG (n = 5), NTG (n = 2) or OHT (n = 23)...
December 31, 2016: International Ophthalmology
Lingshuang Song, Lin Yang, Jie Meng, Sichun Yang
We present a joint experimental-computational study to quantitatively describe the thermodynamics of hydrophobic leucine amino acids in aqueous solution. X-ray scattering data were acquired at a series of solute and salt concentrations to effectively measure interleucine interactions, indicating that a major scattering peak is observed consistently at q = 0.83 Å(-1). Atomistic molecular dynamics simulations were then performed and compared with the scattering data, achieving high consistency at both small and wider scattering angles (q = 0-1...
January 3, 2017: Journal of Physical Chemistry Letters
U Bangert, A Stewart, E O'Connell, E Courtney, Q Ramasse, D Kepatsoglou, H Hofsäss, J Amani, J-S Tu, B Kardynal
Functionalisation of two-dimensional (2-D) materials via low energy ion implantation could open possibilities for fabrication of devices based on such materials. Nanoscale patterning and/or electronically doping can thus be achieved, compatible with large scale integrated semiconductor technologies. Using atomic resolution High Angle Annular Dark Field (HAADF) scanning transmission electron microscopy supported by image simulation, we show that sites and chemical nature of individual implants/ dopants in graphene, as well as impurities in hBN, can uniquely and directly be identified on grounds of their position and their image intensity in accordance with predictions from Z-contrast theories...
December 11, 2016: Ultramicroscopy
Umme Salma, Marianna Usula, Ruggero Caminiti, Lorenzo Gontrani, Natalia V Plechkova, Kenneth R Seddon
The nanostructural organisation of mixtures of the ionic liquid (butylammonium butanoate) and water at several mole fractions of water has been investigated using small and wide angle X-ray scattering (S-WAXS) and molecular dynamics (MD) simulations. The presence of a first sharp diffraction peak (FSDP) in the pure ionic liquid has been observed, experimentally and theoretically, suggesting the possibility of segregation of domains of different polarity in the system. With increasing dilution in water, the prepeak is shifted towards smaller Q values, and becomes very weak, while the principal peak moves towards larger Q values...
December 23, 2016: Physical Chemistry Chemical Physics: PCCP
Brian C Toy, Edward E Manche
OBJECTIVE: To compare the astigmatic outcomes of photorefractive keratectomy (PRK) with a wavefront-guided (WFG) and a wavefront-optimized (WFO) excimer laser performed on two different platforms. METHODS: Setting: institutional. DESIGN: Prospective, randomized, fellow eye comparison clinical trial. PARTICIPANTS: A total of 142 eyes of 71 patients with myopia of 12 diopters (D) or less and astigmatism of 3D or less were enrolled at the Byers Eye Institute at Stanford between April 2009 and March 2011...
December 19, 2016: Eye & Contact Lens
Muhammad A Hasan, Derek Abbott, Mathias Baumert, Sridhar Krishnan
The purpose of this study was to investigate the beat-to-beat variability of T-waves (TWV) and to assess the diagnostic capabilities of T-wave-based features for myocardial infarction (MI). A total of 148 recordings of standard 12-lead electrocardiograms (ECGs) from 79 MI patients (22 females, mean age 63±12 years; 57 males, mean age 57±10 years) and 69 recordings from healthy subjects (HS) (17 females, 42±18 years; 52 males, 40±13 years) were studied. For the quantification of beat-to-beat QT intervals in ECG signal, a template-matching algorithm was applied...
December 21, 2016: Biomedizinische Technik. Biomedical Engineering
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