scholarly journals Quantitative measurement of syndesmophyte volume and height in ankylosing spondylitis using CT

2013 ◽  
Vol 73 (3) ◽  
pp. 544-550 ◽  
Author(s):  
Sovira Tan ◽  
Jianhua Yao ◽  
John A Flynn ◽  
Lawrence Yao ◽  
Michael M Ward
Keyword(s):  
Ankylosing Spondylitis ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Reliability And Validity ◽  
Intervertebral Disk ◽  
Ct Scans ◽  
Developmental Study ◽  
Coefficients Of Variation ◽  
Spine Ct ◽  
Computer Based

ObjectiveSyndesmophyte growth in ankylosing spondylitis can be difficult to measure using radiographs because of poor visualisation and semiquantitative scoring methods. We developed and tested the reliability and validity of a new computer-based method that fully quantifies syndesmophyte volumes and heights on CT scans.MethodsIn this developmental study, we performed lumbar spine CT scans on 38 patients and used our algorithm to compute syndesmophyte volume and height in four intervertebral disk spaces. To assess reliability, we compared results between two scans performed on the same day in nine patients. To assess validity, we compared computed measures to visual ratings of syndesmophyte volume and height on both CT scans and radiographs by two physician readers.ResultsCoefficients of variation for syndesmophyte volume and height, based on repeat scans, were 2.05% and 2.40%, respectively. Based on Bland–Altman analysis, an increase in syndesmophyte volume of more than 4% or in height of more than 0.20 mm represented a change greater than measurement error. Computed volumes and heights were strongly associated with physician ratings of syndesmophyte volume and height on visual examination of both the CT scans (p<0.0001) and plain radiographs (p<0.002). Syndesmophyte volumes correlated with the Schober test (r=−0.48) and lateral thoracolumbar flexion (r=−0.60).ConclusionsThis new CT-based method that fully quantifies syndesmophytes in three-dimensional space had excellent reliability and face and construct validity. Given its high precision, this method shows promise for longitudinal clinical studies of syndesmophyte development and growth.

The Brain Stem Saccadic Burst Generator Encodes Gaze in Three-Dimensional Space

2008 ◽  
Vol 99 (5) ◽  
pp. 2602-2616 ◽  
Author(s):  
Marion R. Van Horn ◽  
Pierre A. Sylvestre ◽  
Kathleen E. Cullen
Keyword(s):  
Eye Movements ◽  
Brain Stem ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Saccadic Eye Movements ◽  
Three Dimensions ◽  
Related Information ◽  
Computer Based ◽  
Different Depths ◽  
The Brain

When we look between objects located at different depths the horizontal movement of each eye is different from that of the other, yet temporally synchronized. Traditionally, a vergence-specific neuronal subsystem, independent from other oculomotor subsystems, has been thought to generate all eye movements in depth. However, recent studies have challenged this view by unmasking interactions between vergence and saccadic eye movements during disconjugate saccades. Here, we combined experimental and modeling approaches to address whether the premotor command to generate disconjugate saccades originates exclusively in “vergence centers.” We found that the brain stem burst generator, which is commonly assumed to drive only the conjugate component of eye movements, carries substantial vergence-related information during disconjugate saccades. Notably, facilitated vergence velocities during disconjugate saccades were synchronized with the burst onset of excitatory and inhibitory brain stem saccadic burst neurons (SBNs). Furthermore, the time-varying discharge properties of the majority of SBNs (>70%) preferentially encoded the dynamics of an individual eye during disconjugate saccades. When these experimental results were implemented into a computer-based simulation, to further evaluate the contribution of the saccadic burst generator in generating disconjugate saccades, we found that it carries all the vergence drive that is necessary to shape the activity of the abducens motoneurons to which it projects. Taken together, our results provide evidence that the premotor commands from the brain stem saccadic circuitry, to the target motoneurons, are sufficient to ensure the accurate control shifts of gaze in three dimensions.

scholarly journals The Three-Dimensional Imaging of Rock Wall Surface with the Use of Computer-Based Image Processing and Analysis

2015 ◽  
Vol 37 (1) ◽  
pp. 53-58
Author(s):  
Krzysztof Oleszko ◽  
Mariusz Młynarczuk
Keyword(s):  
Image Processing ◽  
Dimensional Space ◽  
Low Cost ◽  
Three Dimensional ◽  
Rock Material ◽  
Rock Wall ◽  
Image Processing And Analysis ◽  
Digital Mapping ◽  
Computer Based ◽  
Bit Planes

Abstract The paper presents two methods of digital mapping of rock walls in three dimensional space. The methods have been developed with the use of low-cost devices, which enable image acquisition, and processing methods based on digital image processing and analysis. Both methods are based on so-called shadow profilometry. One of those methods involved mapping the shape of the rock wall on casted mapped surface with analyzed laser lines. The second method was based on the analysis of projected set of bit planes. The planes were projected by computer projector. Both measurement methods have been tested in Miękinia porphyry quarry. The study involved rock wall measurements, which were repeated several times. The part of rock material was removed from the measured wall after each measurement. In order to verify the accuracy of the proposed methods of measurement, volume results obtained and based on digital methods were compared to the volume of removed rock material during measurement. Calculated results were characterized by small deviations which prove to be correct, and are a solid basis for further work on practical application of presented methods.

scholarly journals Spatial distribution of syndesmophytes along the vertebral rim in ankylosing spondylitis: preferential involvement of the posterolateral rim

2016 ◽  
Vol 75 (11) ◽  
pp. 1951-1957 ◽  
Author(s):  
Sovira Tan ◽  
Abhijit Dasgupta ◽  
Jianhua Yao ◽  
John A Flynn ◽  
Lawrence Yao ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Lumbar Spine ◽  
Ankylosing Spondylitis ◽  
Intervertebral Disc ◽  
Uniform Distribution ◽  
Thoracolumbar Spine ◽  
Ct Scans ◽  
Vertebral Endplate ◽  
Vertebral Level ◽  
Spine Ct

ObjectiveSyndesmophytes in ankylosing spondylitis (AS) can occur anywhere along the vertebral rim, but little is known about how and where they develop, and particularly if they first form in certain locations along the rim. This information might provide clues to their aetiology. We examined the spatial distribution of syndesmophytes in the thoracolumbar spine in patients with AS using CT.MethodsWe performed lumbar spine CT scans in 50 patients and used a validated computer algorithm to measure syndesmophyte heights in six intervertebral disc spaces. We measured heights every five radial degrees around the rim of each superior and inferior vertebral endplate.ResultsSyndesmophytes were observed in 208 of 296 intervertebral disc spaces. Both ascending and descending syndesmophytes were non-randomly distributed along the vertebral rim (p<0.0001 for deviation from uniform distribution). Syndesmophytes occurred most often at the posterolateral vertebral rim, and least commonly at the posterior rim and anterior rim. In disc spaces with only small isolated syndesmophytes, these were also most likely to occur at the posterolateral rim. Syndesmophyte distribution varied with the vertebral level. Localisation at the posterolateral rim was most pronounced at T10-T11, T12-T12 and T12-L1, while L2-L3 and L3-L4 exhibited little localisation.ConclusionsSyndesmophytes are not randomly distributed around the vertebral rim, as might be expected if they develop solely in response to inflammation. Rather, they preferentially occur, and likely develop first, at the posterolateral rim. Studying factors that can lead to this pattern may help elucidate how syndesmophytes develop.

scholarly journals Dispersion of Sequences for Generating a Robust Enciphering System

1970 ◽  
Vol 1 (1) ◽  
pp. 9-14
Author(s):  
Tomoyuki Nagase ◽  
Ryusuke Koide ◽  
Takashi Araki ◽  
Yoshiei Hasegawa
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Rotation Matrix ◽  
Public Key ◽  
New Paradigm ◽  
Unit Quaternion ◽  
The Public ◽  
Private Key ◽  
Computer Based ◽  
Three Dimensional Space

This paper introduces a new paradigm for dispersion of information into three-dimensional space to generate a strenuous crypto system. The dispersion of the information is carried out by quaternion rotation matrix which is called quadripartite public-key (QPK). We considered a private key as a unit quaternion which has an arbitrary quadruple of real numbers. The public key has three different components which are constructed using quaternion rotation matrix QRM to generate a secure key, which significantly eliminates the risk of eavesdropping. Furthermore, quaternion has capability to provide a meditative encryption system for wireless images or voice transmissions. A computer-based simulation conducted to scrutinize the capability of QPK carefully in insuring the highest level of security is reported.

Three Dimensional structure and organization of diploid chromosomes by optical section microscopy

1987 ◽  
Vol 45 ◽  
pp. 633-635
Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Developmental State ◽  
Mitotic Cell ◽  
Biological Properties ◽  
Dimensional Structure ◽  
Specific Gene ◽  
Three Dimensional Structure ◽  
Complementary Techniques ◽  
Dynamic Structures

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.

Diffraction contrast of dislocations in icosahedral quasicrystals

1990 ◽  
Vol 48 (4) ◽  
pp. 454-455
Author(s):  
K. Urban ◽  
Z. Zhang ◽  
M. Wollgarten ◽  
D. Gratias
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Complete Characterization ◽  
Extinction Condition ◽  
Burgers Vector ◽  
Diffraction Contrast ◽  
Lattice Geometry ◽  
Reference Space ◽  
Icosahedral Quasicrystals ◽  
The One

Recently dislocations have been observed by electron microscopy in the icosahedral quasicrystalline (IQ) phase of Al65Cu20Fe15. These dislocations exhibit diffraction contrast similar to that known for dislocations in conventional crystals. The contrast becomes extinct for certain diffraction vectors g. In the following the basis of electron diffraction contrast of dislocations in the IQ phase is described. Taking account of the six-dimensional nature of the Burgers vector a “strong” and a “weak” extinction condition are found.Dislocations in quasicrystals canot be described on the basis of simple shear or insertion of a lattice plane only. In order to achieve a complete characterization of these dislocations it is advantageous to make use of the one to one correspondence of the lattice geometry in our three-dimensional space (R3) and that in the six-dimensional reference space (R6) where full periodicity is recovered . Therefore the contrast extinction condition has to be written as gpbp + gobo = 0 (1). The diffraction vector g and the Burgers vector b decompose into two vectors gp, bp and go, bo in, respectively, the physical and the orthogonal three-dimensional sub-spaces of R6.

Flavin radicals, conformational sampling and robust design principles in interprotein electron transfer: the trimethylamine dehydrogenase-electron-transferring flavoprotein complex

2004 ◽  
Vol 71 ◽  
pp. 1-14
Author(s):  
David Leys ◽  
Jaswir Basran ◽  
François Talfournier ◽  
Kamaldeep K. Chohan ◽  
Andrew W. Munro ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Kinetic Studies ◽  
Molecular Assembly ◽  
Conformational Sampling ◽  
Trimethylamine Dehydrogenase ◽  
Key Residues ◽  
Electron Transferring Flavoprotein ◽  
Electron Transfer Complex

TMADH (trimethylamine dehydrogenase) is a complex iron-sulphur flavoprotein that forms a soluble electron-transfer complex with ETF (electron-transferring flavoprotein). The mechanism of electron transfer between TMADH and ETF has been studied using stopped-flow kinetic and mutagenesis methods, and more recently by X-ray crystallography. Potentiometric methods have also been used to identify key residues involved in the stabilization of the flavin radical semiquinone species in ETF. These studies have demonstrated a key role for 'conformational sampling' in the electron-transfer complex, facilitated by two-site contact of ETF with TMADH. Exploration of three-dimensional space in the complex allows the FAD of ETF to find conformations compatible with enhanced electronic coupling with the 4Fe-4S centre of TMADH. This mechanism of electron transfer provides for a more robust and accessible design principle for interprotein electron transfer compared with simpler models that invoke the collision of redox partners followed by electron transfer. The structure of the TMADH-ETF complex confirms the role of key residues in electron transfer and molecular assembly, originally suggested from detailed kinetic studies in wild-type and mutant complexes, and from molecular modelling.

Topics in Quaternion Linear Algebra

2014 ◽  
Author(s):  
Leiba Rodman
Keyword(s):  
Linear Algebra ◽  
Complex Analysis ◽  
Dimensional Space ◽  
Applied Mathematics ◽  
Three Dimensional ◽  
Number System ◽  
Graduate Course ◽  
Open Problems ◽  
Unpublished Research ◽  
Reference Tool

Quaternions are a number system that has become increasingly useful for representing the rotations of objects in three-dimensional space and has important applications in theoretical and applied mathematics, physics, computer science, and engineering. This is the first book to provide a systematic, accessible, and self-contained exposition of quaternion linear algebra. It features previously unpublished research results with complete proofs and many open problems at various levels, as well as more than 200 exercises to facilitate use by students and instructors. Applications presented in the book include numerical ranges, invariant semidefinite subspaces, differential equations with symmetries, and matrix equations. Designed for researchers and students across a variety of disciplines, the book can be read by anyone with a background in linear algebra, rudimentary complex analysis, and some multivariable calculus. Instructors will find it useful as a complementary text for undergraduate linear algebra courses or as a basis for a graduate course in linear algebra. The open problems can serve as research projects for undergraduates, topics for graduate students, or problems to be tackled by professional research mathematicians. The book is also an invaluable reference tool for researchers in fields where techniques based on quaternion analysis are used.

Extension of the Spatial PDI Model to Three Dimensions

1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien
Keyword(s):  
Population Density ◽  
Dimensional Space ◽  
Finite Lattice ◽  
Three Dimensional ◽  
Upper Bounds ◽  
Three Dimensions ◽  
Lower And Upper Bounds ◽  
Density Index ◽  
Three Dimensional Space

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.

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