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fractal dimension

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https://www.readbyqxmd.com/read/28102955/compound-speckle-model-detects-anti-angiogenic-tumor-response-in-preclinical-nonlinear-contrast-enhanced-ultrasonography
#1
Matthew R Lowerison, Justin J Tse, M Nicole Hague, Ann F Chambers, David W Holdsworth, James C Lacefield
PURPOSE: This paper proposes a method for analyzing the first-order speckle statistics of nonlinear contrast-enhanced ultrasound images from tumors. METHODS: Contrast signal intensity is modeled as a compound distribution of exponential probability density functions with a gamma weighting function. The gamma probability weighting function serves as an approximation for log-normally distributed flow velocities in a vascular network. The model was applied to sub-harmonic bolus-injection images acquired from a mouse breast cancer xenograft model treated with murine version bevacizumab...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28100181/gestational-diabetes-mellitus-and-retinal-microvasculature
#2
Ling-Jun Li, Michael Kramer, Robyn J Tapp, Ryan E K Man, Ngee Lek, Shirong Cai, Fabian Yap, Peter Gluckman, Kok Hian Tan, Yap Seng Chong, Jia Yu Koh, Seang Mei Saw, Yin Bun Cheung, Tien Yin Wong
BACKGROUND: Small-vessel dysfunction may be an important consequence of chronic hyperglycemia. We examined the association between gestational diabetes mellitus (GDM), a state of transient hyperglycemia during pregnancy, and retinal microvascular changes in pregnant women at 26-28 weeks of pregnancy. METHODS: A total of 1136 pregnant women with singleton pregnancies were recruited during their first trimester at two major Singapore maternity hospitals in an on-going birth cohort study...
January 18, 2017: BMC Ophthalmology
https://www.readbyqxmd.com/read/28094311/evidence-of-microvascular-changes-in-the-retina-following-kawasaki-disease
#3
Katherine Y H Chen, David P Burgner, Tien Y Wong, Seang Mei Saw, Swee Chye Quek, Audrey Y C Pang, Seo Wei Leo, Inez B Wong, Diana Zannino, Nigel Curtis, Michael Cheung, Carol Y Cheung, Terence C W Lim
It is unclear whether all children with Kawasaki disease (KD) have increased later cardiovascular risk. The retinal microvasculature reflects changes in the microcirculation and is associated with traditional cardiovascular risk factors and events. The aim of this study was to investigate retinal microvascular parameters in two populations of patients with previous KD and control participants. We performed case-control studies of 116 (57 patients and 59 control participants) Australian and 156 (78 patients and 78 control participants) Singaporean individuals, at least two years since their acute illness...
January 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28088542/interaction-of-earthworms-microbe-facilitating-biofilm-dewaterability-performance-during-wasted-activated-sludge-reduction-and-stabilization
#4
Yadan Zheng, Meiyan Xing, Luziyu Cai, Tao Xiao, Yufan Lu, Jinzhou Jiang
Sludge dewaterability was chemically and morphologically explored during sewage sludge treatment by vermifiltration. The results, with a conventional biofilter (BF, no earthworms) as a control, demonstrated that the capillary suction time(CST) and specific resistance of filtration(SRF) of vermifilter (VF, with earthworms) treated sludge were 64.9±1.7s and (23.1±1.3)×10(12)m/kg,16.8% and 36.0% lower than that of the BF, respectively. Additionally, the VF could efficiently decompose loosely bound extracellular polymeric substances (LB-EPS), releasing more water trapped inside biofilm...
January 11, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28079249/fractal-analysis-of-visual-search-activity-for-mass-detection-during-mammographic-screening
#5
Folami Alamudun, Hong-Jun Yoon, Kathleen B Hudson, Garnetta Morin-Ducote, Tracy Hammond, Georgia D Tourassi
PURPOSE: The objective of this study is to assess the complexity of human visual search activity during mammographic screening using fractal analysis and to investigate its relationship with case and reader characteristics. METHODS: The study was performed for the task of mammographic screening with simultaneous viewing of four coordinated breast views as typically done in clinical practice. Eye-tracking data and diagnostic decisions collected for 100 mammographic cases (25 normal, 25 benign, 50 malignant) and 10 readers (three board certified radiologists and seven radiology residents), formed the corpus data for this study...
January 12, 2017: Medical Physics
https://www.readbyqxmd.com/read/28075432/aggregation-and-deposition-of-in-situ-formed-colloidal-particles-in-the-presence-of-polyelectrolytes
#6
Feng Li, Dejun Sun, Tao Wu, Yujiang Li
In this work, aggregation and deposition of in situ formed magnesium hydroxide (IFM) in the presence of hydrolyzed polyacrylamide (HPAM) were investigated. Relative concentrations of interactants, as well as other experimental conditions, were changed to elucidate the interaction mechanisms from microscopic to macroscopic levels. Light scattering measurements were used to investigate the aggregation kinetics, fractal dimension, and collision efficiency of the aggregates on a microscopic level. Electrophoretic mobility and TEM were utilized to measure the charging properties and morphologies of aggregates, respectively...
January 11, 2017: Soft Matter
https://www.readbyqxmd.com/read/28072842/fractal-analysis-of-brain-blood-oxygenation-level-dependent-bold-signals-from-children-with-mild-traumatic-brain-injury-mtbi
#7
Olga Dona, Michael D Noseworthy, Carol DeMatteo, John F Connolly
BACKGROUND: Conventional imaging techniques are unable to detect abnormalities in the brain following mild traumatic brain injury (mTBI). Yet patients with mTBI typically show delayed response on neuropsychological evaluation. Because fractal geometry represents complexity, we explored its utility in measuring temporal fluctuations of brain resting state blood oxygen level dependent (rs-BOLD) signal. We hypothesized that there could be a detectable difference in rs-BOLD signal complexity between healthy subjects and mTBI patients based on previous studies that associated reduction in signal complexity with disease...
2017: PloS One
https://www.readbyqxmd.com/read/28067200/quantitative-angiography-methods-for-bifurcation-lesions-a-consensus-statement-update-from-the-european-bifurcation-group
#8
Carlos Collet, Yoshinobu Onuma, Rafael Cavalcante, Maik Grundeken, Philippe Généreux, Jeffrey Popma, Ricardo Costa, Goran Stankovic, Shengxian Tu, Johan H C Reiber, Jean-Paul Aben, Jens Flensted Lassen, Yves Louvard, Alexandra Lansky, Patrick W Serruys
Bifurcation lesions represent one of the most challenging lesions subset in interventional cardiology. The European Bifurcation Club (EBC) is an academic consortium whose goal has been to assess and recommend the appropriate strategies to manage bifurcation lesions. The quantitative coronary angiography (QCA) methods for the evaluation of bifurcation lesions has been subject to extensive research. Single vessel quantitative coronary angiography (QCA) has shown to be inaccurate to assess bifurcation lesions dimensions...
January 10, 2017: EuroIntervention
https://www.readbyqxmd.com/read/28063435/local-structure-of-percolating-gels-at-very-low-volume-fractions
#9
Samuel Griffiths, Francesco Turci, C Patrick Royall
The formation of colloidal gels is strongly dependent on the volume fraction of the system and the strength of the interactions between the colloids. Here we explore very dilute solutions by the means of numerical simulations and show that, in the absence of hydrodynamic interactions and for sufficiently strong interactions, percolating colloidal gels can be realised at very low values of the volume fraction. Characterising the structure of the network of the arrested material we find that, when reducing the volume fraction, the gels are dominated by low-energy local structures, analogous to the isolated clusters of the interaction potential...
January 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28058083/simulating-the-hydrodynamics-of-self-propelled-colloidal-clusters-using-stokesian-dynamics
#10
Yousef M F El Hasadi, Martin Crapper
Self-propelled clusters are involved in many technological applications such as in material science and biotechnology, and understanding their interaction with the fluid that surrounds them is of a great importance. We present results of swimming velocity and energy dissipation obtained through Stokesian dynamics simulations of self-propelled clusters. The clusters are of diffusion limited aggregates, consisting of force- and torque-free spherical particles. The number of particles per cluster ranges from 100 to 400, and with two fractal dimensions of 2...
November 2016: Biomicrofluidics
https://www.readbyqxmd.com/read/28054690/small-angle-scattering-from-the-cantor-surface-fractal-on-the-plane-and-the-koch-snowflake
#11
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 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28048783/su-f-r-30-interscanner-variability-of-radiomics-features-in-computed-tomography-ct-using-a-standard-acr-phantom
#12
M Shafiq Ul Hassan, M Budzevich, G Zhang, K Latifi, D Hunt, R Gillies, E Moros
PURPOSE: A simple approach to investigate Interscanner variability of Radiomics features in computed tomography (CT) using a standard ACR phantom. METHODS: The standard ACR phantom was scanned on CT scanners from three different manufacturers. Scanning parameters of 120 KVp, 200 mA were used while slice thickness of 3.0 mm on two scanners and 3.27 mm on third scanner was used. Three spherical regions of interest (ROI) from water, medium density and high density inserts were contoured...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046757/mo-de-207b-04-impact-of-reconstruction-field-of-view-on-radiomics-features-in-computed-tomography-ct-using-a-texture-phantom
#13
M Shafiq Ul Hassan, G Zhang, K Latifi, J Oliver, D Hunt, R Guzman, Y Balagurunathan, D Mackin, L Court, R Gillies, E Moros
PURPOSE: To investigate the impact of reconstruction Field of View on Radiomics features in computed tomography (CT) using a texture phantom. METHODS: A rectangular Credence Cartridge Radiomics (CCR) phantom, composed of 10 different cartridges, was scanned on four different CT scanners from two manufacturers. A pre-defined scanning protocol was adopted for consistency. The slice thickness and reconstruction interval of 1.5 mm was used on all scanners. The reconstruction FOV was varied to result a voxel size ranging from 0...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28039830/characterization-of-silver-nanoparticle-aggregates-using-single-particle-inductively-coupled-plasma-mass-spectrometry-spicp-ms
#14
Hyun-A Kim, Byung-Tae Lee, So-Young Na, Kyoung-Woong Kim, James F Ranville, Soon-Oh Kim, Eunhye Jo, Ig-Chun Eom
The single particle-inductively coupled plasma-mass spectrometry was applied to characterize the aggregates of AgNPs. was applied to characterize the aggregates of AgNPs. Two sizes of citrate-AgNPs and PVP-AgNPs were used at relatively high and predicted environmental concentrations under various ionic strengths. Citrate-AgNP aggregated with increases in the ionic strength, whereas PVP-AgNPs were sterically stable. The critical coagulation concentrations were 85 mM and 100 mM NaNO3 for 60 nm and 100 nm citrate-AgNPs at 2 mg L(-1) as total Ag obtained by dynamic light scattering (DLS)...
December 19, 2016: Chemosphere
https://www.readbyqxmd.com/read/28033115/quantification-of-differences-between-nailfold-capillaroscopy-images-with-a-scleroderma-pattern-and-normal-pattern-using-measures-of-geometric-and-algorithmic-complexity
#15
Samuel George Urwin, Bridget Griffiths, John Allen
This study aimed to quantify and investigate differences in the geometric and algorithmic complexity of the microvasculature in nailfold capillaroscopy (NFC) images displaying a scleroderma pattern and those displaying a 'normal' pattern. 11 NFC images were qualitatively classified by a capillary specialist as indicative of 'clear microangiopathy' (CM), i.e. a scleroderma pattern, and 11 as 'not clear microangiopathy' (NCM), i.e. a 'normal' pattern. Pre-processing was performed, and fractal dimension (FD) and Kolmogorov complexity (KC) were calculated following image binarisation...
December 29, 2016: Physiological Measurement
https://www.readbyqxmd.com/read/28027466/dynamics-of-aggregate-size-and-shape-properties-under-sequenced-flocculation-in-a-turbulent-taylor-couette-reactor
#16
Léa Guérin, Carole Coufort-Saudejaud, Alain Liné, Christine Frances
This paper concerns experimental investigation of the sequenced flocculation of latex particles in a Taylor-Couette reactor. The aim of this work was to investigate the evolution of both the size and the shape of aggregates under sequenced hydrodynamics. A number of studies have focused on the evolution of the aggregate size or size distribution during steps of growth-breakage-regrowth, but aggregates generally experience steps of breakage-regrowth on repeated occasions in real operating conditions (passages near the impeller or during the transfer processes, for example)...
December 21, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28026197/what-paint-can-tell-us-a-fractal-analysis-of-neurological-changes-in-seven-artists
#17
Alex Forsythe, Tamsin Williams, Ronan G Reilly
OBJECTIVE: The notion that artistic capability increases with dementia is both novel and largely unsupported by available literature. Recent research has suggested an emergence of artistic capabilities to be a by-product of involuntary behaviour seen with dementia, as opposed to a progression in original thinking (de Souza, et al., 2010). A far more complementary explanation comes from Hannemann (2006), who suggests that art offers an outlet for dementia patients to refine and sharpen their cognitive abilities...
January 2017: Neuropsychology
https://www.readbyqxmd.com/read/28010915/the-use-of-tomosynthesis-in-the-global-study-of-knee-subchondral-insufficiency-fractures
#18
Fred Nelson, Omaima Bokhari, Daniel Oravec, Woong Kim, Michael Flynn, Catherine Lumley, Austin McPhilamy, Yener N Yeni
RATIONALE AND OBJECTIVES: Subchondral insufficiency fractures (SIF), previously termed spontaneous osteonecrosis of the knee, are marked by a sudden onset of severe pain. Other than the size of the lesion, prediction for progression to joint replacement is difficult. The objective was to determine if quantitative analysis of bone texture using digital tomosynthesis imaging would be useful in predicting more rapid progression to joint replacement. MATERIALS AND METHODS: Tomosynthesis studies of 30 knees with documented SIF were quantified by fractal, mean intercept length (MIL), and line fraction deviation analyses...
December 20, 2016: Academic Radiology
https://www.readbyqxmd.com/read/28002443/distributional-variations-in-the-quantitative-cortical-and-trabecular-bone-radiographic-measurements-of-mandible-between-male-and-female-populations-of-korea-and-its-utilization
#19
Muthu Subash Kavitha, Soon-Yong Park, Min-Suk Heo, Sung-Il Chien
It is important to investigate the irregularities in aging-associated changes in bone, between men and women for bone strength and osteoporosis. The purpose of this study was to characterize the changes and associations of mandibular cortical and trabecular bone measures of men and women based on age and to the evaluation of cortical shape categories, in a large Korean population. Panoramic radiographs of 1047 subjects (603 women and 444 men) aged between 15 to 90 years were used. Mandibular cortical width (MCW), mandibular cortical index (MCI), and fractal dimensions (FD) of the molar, premolar, and anterior regions of the mandibular trabecular bone were measured...
2016: PloS One
https://www.readbyqxmd.com/read/28002429/inter-gender-semg-evaluation-of-central-and-peripheral-fatigue-in-biceps-brachii-of-young-healthy-subjects
#20
Federico Meduri, Matteo Beretta-Piccoli, Luca Calanni, Valentina Segreto, Giuseppe Giovanetti, Marco Barbero, Corrado Cescon, Giuseppe D'Antona
PURPOSE: The purpose of the present study was to evaluate inter-arm and inter-gender differences in fractal dimension (FD) and conduction velocity (CV) obtained from multichannel surface electromyographic (sEMG) recordings during sustained fatiguing contractions of the biceps brachii. METHODS: A total of 20 recreationally active males (24±6 years) and 18 recreationally active females (22±9 years) performed two isometric contractions at 120 degrees elbow joint angle: (1) at 20% maximal voluntary contraction (MVC) for 90 s, and (2) at 60% MVC until exhaustion the time to perform the task has been measured...
2016: PloS One
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