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https://www.readbyqxmd.com/read/28088625/absence-of-dj-1-causes-age-related-retinal-abnormalities-in-association-with-increased-oxidative-stress
#1
Vera L Bonilha, Brent A Bell, Mary E Rayborn, Ivy S Samuels, Anna King, Joe G Hollyfield, Chengsong Xie, Huaibin Cai
Oxidative stress alters physiological function in most biological tissues and can lead to cell death. In the retina, oxidative stress initiates a cascade of events leading to focal loss of RPE and photoreceptors, which is thought to be a major contributing factor to geographic atrophy. Despite these implications, the molecular regulation of RPE oxidative stress under normal and pathological conditions remains largely unknown. A better understanding of the mechanisms involved in regulating RPE and photoreceptors oxidative stress response is greatly needed...
January 11, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28079527/binary-moving-blocker-based-scatter-correction-in-cone-beam-computed-tomography-with-width-truncated-projections-proof-of-concept
#2
Ho Lee, Benjamin Fahimian, Lei Xing
This paper proposes a binary moving-blocker (BMB)-based technique for scatter correction in cone-beam computed tomography (CBCT). In concept, a beam blocker consisting of lead strips, mounted in front of the x-ray tube, moves rapidly in and out of the beam during a single gantry rotation. The projections are acquired in alternating phases of blocked and unblocked cone beams, where the blocked phase results in a stripe pattern in the width direction. To derive the scatter map from the blocked projections, one-dimensional B-Spline interpolation/extrapolation is applied by using the detected information in the shaded regions...
January 12, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28074469/development-of-cone-photoreceptors-and-their-synapses-in-the-human-and-monkey-fovea
#3
Anita Hendrickson, Chi Zhang
During retinal development, ribbon synapse assembly in the photoreceptors is a crucial step involving numerous molecules. While the developmental sequence of plexiform layers in human retina has been characterized, the molecular steps of synaptogenesis remain largely unknown. In the present study, we focused on the central rod-free region of primate retina, the fovea, to specifically investigate the development of cone photoreceptor ribbon synapses. Immunocytochemistry and electron microscopy were utilized to track the expression of photoreceptor transduction proteins and ribbon and synaptic markers in fetal human and Macaca retina...
January 11, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28072395/evaluation-of-adaptive-treatment-planning-for-patients-with-non-small-cell-lung-cancer
#4
Hualiang Zhong, Salim Siddiqui, Benjamin Movsas, Indrin Chetty
The purpose of this study was to develop metrics to evaluate uncertainties in deformable dose accumulation (DDA) for patients with non-small cell lung cancer (NSCLC). Initial treatment plans (primary) and cone-beam CT (CBCT) images were retrospectively processed for seven NSCLC patients, who showed significant tumor regression during the course of treatment. Each plan was developed with IMRT for 2 Gy��33 fractions. A B-spline-based DIR algorithm was used to register weekly CBCT images to a reference image acquired at fraction 21 and the resultant displacement vector fields (DVFs) were then modified using a finite element method (FEM)...
January 10, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28067241/multiple-dirac-cones-at-the-surface-of-the-topological-metal-labi
#5
Jayita Nayak, Shu-Chun Wu, Nitesh Kumar, Chandra Shekhar, Sanjay Singh, Jörg Fink, Emile E D Rienks, Gerhard H Fecher, Stuart S P Parkin, Binghai Yan, Claudia Felser
The rare-earth monopnictide LaBi exhibits exotic magneto-transport properties, including an extremely large and anisotropic magnetoresistance. Experimental evidence for topological surface states is still missing although band inversions have been postulated to induce a topological phase in LaBi. In this work, we have revealed the existence of surface states of LaBi through the observation of three Dirac cones: two coexist at the corners and one appears at the centre of the Brillouin zone, by employing angle-resolved photoemission spectroscopy in conjunction with ab initio calculations...
January 9, 2017: Nature Communications
https://www.readbyqxmd.com/read/28066676/image-guided-localization-of-small-lung-nodules-in-video-assisted-thoracic-surgery
#6
REVIEW
Ze-Rui Zhao, Rainbow W H Lau, Peter S Y Yu, Randolph H L Wong, Calvin S H Ng
The advancement of imaging technology has recently facilitated single port minimally-invasive thoracic surgery techniques. Cone-beam computed tomography (CBCT) shows promising results in visualizing the target lesion and its surrounding critical anatomy, with an error of less than 2 mm. The integration of CBCT with the operating room (OR) to form the hybrid OR, provides unparalleled real-time imaging of the patient, which can be used with electromagnetic navigation bronchoscopy to confirm successful navigation and increase procedural accuracy particularly for small peripheral pulmonary targets...
October 2016: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/28065198/random-spatial-patterning-of-cone-bipolar-cell-mosaics-in-the-mouse-retina
#7
Patrick W Keeley, Jason J Kim, Sammy C S Lee, Silke Haverkamp, Benjamin E Reese
Retinal bipolar cells spread their dendritic arbors to tile the retinal surface, extending them to the tips of the dendritic fields of their homotypic neighbors, minimizing dendritic overlap. Such uniform nonredundant dendritic coverage of these populations would suggest a degree of spatial order in the properties of their somal distributions, yet few studies have examined the patterning in retinal bipolar cell mosaics. The present study examined the organization of two types of cone bipolar cells in the mouse retina, the Type 2 cells and the Type 4 cells, and compared their spatial statistical properties with those of the horizontal cells and the cholinergic amacrine cells, as well as to random simulations of cells matched in density and constrained by soma size...
January 2017: Visual Neuroscience
https://www.readbyqxmd.com/read/28064548/amniotic-fluid-sludge-prevalence-and-clinical-significans-of-it-in-asymptomatic-patients-at-high-risk-for-spontaneous-preterm-delivery
#8
Ilknur Adanir, Ozgur Ozyuncu, Ayse Filiz Gokmen Karasu, Lutfu S Onderoglu
INTRODUCTION: The aim of our study is to determine prevalence and clinical significance of the presence of amniotic fluid 'sludge' among asymptomatic patients at high-risk for spontaneous preterm delivery, prospectively. MATERIAL AND METHODS: In our study, 99 patients at high risk for spontaneous preterm delivery were evaluated for the presence of amniotic fluid sludge with transvaginal ultrasonography at 20-22., 26-28. and 32-34. gestational weeks, prospectively; between August 2009 and October 2010 in Hacettepe University Hospital...
January 8, 2017: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/28062100/the-effects-of-below-elbow-immobilization-on-driving-performance
#9
Evan M Jones, Aaron E Barrow, Nic J Skordas, David P Green, Mickey S Cho
INTRODUCTION: There is limited research to guide physicians and patients in deciding whether it is safe to drive while wearing various forms of upper extremity immobilization. The purpose of this study is to evaluate the effect of below-elbow removable splints and fiberglass casts on automobile driving performance. METHODS: 20 healthy subjects completed 10 runs through a closed, cone-marked driving course while wearing a randomized sequence of four different types of immobilization on each extremity (short arm thumb spica fiberglass cast, short arm fiberglass cast, short arm thumb spica splint, and short arm wrist splint)...
December 28, 2016: Injury
https://www.readbyqxmd.com/read/28061512/assessment-of-rod-cone-and-intrinsically-photosensitive-retinal-ganglion-cell-contributions-to-the-canine-chromatic-pupillary-response
#10
Connie Y Yeh, Kristin L Koehl, Christine D Harman, Simone Iwabe, José M Guzman, Simon M Petersen-Jones, Randy H Kardon, András M Komáromy
Purpose: The purpose of this study was to evaluate a chromatic pupillometry protocol for specific functional assessment of rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs) in dogs. Methods: Chromatic pupillometry was tested and compared in 37 dogs in different stages of primary loss of rod, cone, and combined rod/cone and optic nerve function, and in 5 wild-type (WT) dogs. Eyes were stimulated with 1-s flashes of dim (1 cd/m2) and bright (400 cd/m2) blue light (for scotopic conditions) or bright red (400 cd/m2) light with 25-cd/m2 blue background (for photopic conditions)...
January 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28060499/correlating-reactivity-and-selectivity-to-cyclopentadienyl-ligand-properties-in-rh-iii-catalyzed-c-h-activation-reactions-an-experimental-and-computational-study
#11
Tiffany Piou, Fedor Romanov-Michailidis, Maria Romanova-Michaelides, Kelvin E Jackson, Natthawat Semakul, Trevor D Taggart, Brian S Newell, Christopher D Rithner, Robert S Paton, Tomislav Rovis
Cp(X)Rh(III)-catalyzed C-H functionalization reactions are a proven method for the efficient assembly of small molecules. However, rationalization of the effects of cyclopentadienyl (Cp(X)) ligand structure on reaction rate and selectivity has been viewed as a black box, and a truly systematic study is lacking. Consequently, predicting the outcomes of these reactions is challenging because subtle variations in ligand structure can cause notable changes in reaction behavior. A predictive tool is, nonetheless, of considerable value to the community as it would greatly accelerate reaction development...
January 6, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28060075/removal-and-repositioning-of-intracorneal-ring-segments-improving-corneal-topography-and-clinical-outcomes-in-keratoconus-and-ectasia
#12
Kahei Chan, Peter S Hersh
PURPOSE: To evaluate the efficacy of removal and relocation of intracorneal ring segments for improving outcomes in treatment of keratoconus and corneal ectasia. METHODS: This is a retrospective case series conducted at a cornea and refractive surgery subspecialty practice setting. Patients with previous insertion of 2 intracorneal ring segments underwent surgical removal and repositioning of segments because of unsatisfactory visual and topographic outcomes. The principal outcomes included uncorrected and corrected visual acuities, manifest refraction, topography-derived maximum keratometry (Kmax), inferior-superior topography power difference (I - S), and higher-order aberration profile derived from wavefront analysis...
February 2017: Cornea
https://www.readbyqxmd.com/read/28054342/diversity-of-photoreceptor-arrangements-in-nocturnal-cathemeral-and-diurnal-malagasy-lemurs
#13
Leo Peichl, Alexander Kaiser, Felix Rakotondraparany, Richard R Dubielzig, Steven M Goodman, And Peter M Kappeler
The lemurs of Madagascar (Primates: Lemuriformes) are a monophyletic group that has lived in isolation from other primates for about 50 million years. Lemurs have diversified into species with diverse daily activity patterns and correspondingly different visual adaptations. We assessed the arrangements of retinal cone and rod photoreceptors in six nocturnal, three cathemeral and two diurnal lemur species and quantified different parameters in six of the species. The analysis revealed lower cone densities and higher rod densities in the nocturnal than in the cathemeral and diurnal species...
January 5, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28048931/su-f-t-638-is-there-a-need-for-immobilization-in-srs
#14
K Masterova, A Sethi, D Anderson, V Prabhu, I Rusu, S Gros, E Melian
PURPOSE: Frameless Stereotactic radiosurgery (SRS) is increasingly used in the clinic. Cone-Beam CT (CBCT) to simulation-CT match has replaced the 3-dimensional coordinate based set up using a stereotactic localizing frame. The SRS frame however served as both a localizing and immobilizing device. We seek to measure the quality of frameless (mask based) and frame based immobilization and evaluate its impact on target dose. METHODS: Each SRS patient was set up by kV on-board imaging (OBI) and then fine-tuned with CBCT...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048870/su-f-j-81-evaluation-of-automated-deformable-registration-between-planning-computed-tomography-ct-and-daily-cone-beam-ct-images-over-the-course-of-prostate-cancer-radiotherapy
#15
J Matney, J Hammers, O Kaidar-Person, A Wang, R Chen, S Das, L Marks, P Mavroidis
PURPOSE: To compute daily dose delivered during radiotherapy, deformable registration needs to be relatively fast, automated, and accurate. The aim of this study was to evaluate the performance of commercial deformable registration software for deforming between two modalities: planning computed tomography (pCT) images acquired for treatment planning and cone beam (CB) CT images acquired prior to each fraction of prostate cancer radiotherapy. METHODS: A workflow was designed using MIM Software™ that aligned and deformed pCT into daily CBCT images in two steps: (1) rigid shifts applied after daily CBCT imaging to align patient anatomy to the pCT and (2) normalized intensity-based deformable registration to account for interfractional anatomical variations...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048865/mo-de-207a-08-four-dimensional-cone-beam-ct-iterative-reconstruction-with-time-ordered-chain-graph-model-for-non-periodic-organ-motion-and-deformation
#16
M Nakano, A Haga, J Kotoku, T Magome, Y Masutani, S Hanaoka, K Nakagawa
PURPOSE: The purpose of this study is to propose a new concept of four-dimensional (4D) cone-beam CT (CBCT) reconstruction for non-periodic organ motion using the Time-ordered Chain Graph Model (TCGM), and to compare the reconstructed results with the previously proposed methods, the total variation-based compressed sensing (TVCS) and prior-image constrained compressed sensing (PICCS). METHODS: CBCT reconstruction method introduced in this study consisted of maximum a posteriori (MAP) iterative reconstruction combined with a regularization term derived from a concept of TCGM, which includes a constraint coming from the images of neighbouring time-phases...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048844/su-f-j-70-monte-carlo-study-on-a-cone-beam-computed-tomography-using-a-cross-type-carbon-fiber-antiscatter-grid
#17
K Usui, T Inoue, C Kurokawa, S Sugimoto, K Sasai, K Ogawa
PURPOSE: If a cone-beam computed tomography (CBCT) image can be used for adaptive radiotherapy (ART), an irradiated actual dose distribution can be verified on every treatment day. However, a CBCT image is commonly degraded by scattered photons and thus cannot be directly used for dose calculation. The purpose of the present study is to evaluate whether a cross-type carbon fiber antiscatter grid improves CBCT image quality using a Monte Carlo (MC) method for achieving CBCT-based ART. METHODS: We designed a new carbon fiber (C6 H10 O5 ) interspaced grid, which allows the grid ratio to be increased while maintaining the transmission of primary photons...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048791/su-f-j-48-effect-of-scan-length-on-magnitude-of-imaging-dose-in-kv-cbct
#18
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
https://www.readbyqxmd.com/read/28048776/su-f-j-77-variations-in-the-displacement-vector-fields-calculated-by-different-deformable-image-registration-algorithms-used-in-helical-axial-and-cone-beam-ct-images-of-a-mobile
#19
I Ali, J Jaskowiak, N Alsbou, S Ahmad
PURPOSE: To investigate quantitatively the displacement-vector-fields (DVF) obtained from different deformable image registration algorithms (DIR) in helical (HCT), axial (ACT) and cone-beam CT (CBCT) to register CT images of a mobile phantom and its correlation with motion amplitudes and frequencies. METHODS: HCT, ACT and CBCT are used to image a mobile phantom which includes three targets with different sizes that are manufactured from water-equivalent material and embedded in low density foam...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048629/tu-h-campus-jep2-04-deriving-delivered-doses-to-assess-the-viability-of-2-5-mm-margins-in-head-and-neck-sbrt
#20
S Lin, Q Shang, S Pirozzi, A Godley
PURPOSE: To calculate the delivered dose for head and neck SBRT patients using pre-treatment images. This delivered dose was then used to determine the viability of 2.5 mm margins. METHODS: Daily cone beam CTs (CBCTs) were collected for 20 patients along with a planning CT, planned dose, and planning structures. The day 1 CBCT was aligned to the planning CT using the treatment shifts (six degrees of freedom) and then the dose and contours were transferred to the CBCT...
June 2016: Medical Physics
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