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fractal dimension

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https://www.readbyqxmd.com/read/29329992/eus-elastography-strain-ratio-and-fractal-based-quantitative-analysis-for-the-diagnosis-of-solid-pancreatic-lesions
#1
Silvia Carrara, Milena Di Leo, Fabio Grizzi, Loredana Correale, Rahal Daoud, Andrea Anderloni, Francesco Auriemma, Alessandro Fugazza, Paoletta Preatoni, Roberta Maselli, Cesare Hassan, Elena Finati, Benedetto Mangiavillano, Alessandro Repici
BACKGROUND AND AIMS: EUS elastography is useful in characterizing solid pancreatic lesions (SPLs), and fractal analysis-based technology has been used to evaluate geometric complexity in oncology. The aim of this study was to evaluate EUS elastography (strain ratio) and fractal analysis for the characterization of SPLs. METHODS: Consecutive patients with SPLs were prospectively enrolled between December 2015 and February 2017. Elastographic evaluation included parenchymal strain ratio (pSR) and wall strain ratio (wSR) and was performed with the EU-ME2 processor (Olympus)...
January 9, 2018: Gastrointestinal Endoscopy
https://www.readbyqxmd.com/read/29321857/a-holistic-approach-to-determine-tree-structural-complexity-based-on-laser-scanning-data-and-fractal-analysis
#2
Dominik Seidel
The three-dimensional forest structure affects many ecosystem functions and services provided by forests. As forests are made of trees it seems reasonable to approach their structure by investigating individual tree structure. Based on three-dimensional point clouds from laser scanning, a newly developed holistic approach is presented that enables to calculate the box dimension as a measure of structural complexity of individual trees using fractal analysis. It was found that the box dimension of trees was significantly different among the tested species, among trees belonging to the same species but exposed to different growing conditions (at gap vs...
January 2018: Ecology and Evolution
https://www.readbyqxmd.com/read/29318954/contribution-of-limbs-actions-to-the-four-competitive-swimming-strokes-a-nonlinear-approach
#3
Raul F Bartolomeu, Mário J Costa, Tiago M Barbosa
The aim of our study was to assess the effect of the limbs' actions on the nonlinear properties of the four competitive swimming strokes. Forty-nine swimmers performed all-out sprints at front-crawl, backstroke, breaststroke and butterfly, each one at full stroke (FS), only the arms' stroke (AS), and only leg kicking (LK), in a total of 12 bouts, 6 per day. A speedo-meter cable was attached to the swimmer's hip, to collect the speed-time raw data (f = 50Hz). Velocity, speed fluctuation, sample entropy and fractal dimension were derived from the speed-time series...
January 10, 2018: Journal of Sports Sciences
https://www.readbyqxmd.com/read/29306275/widom-line-dynamical-crossover-and-percolation-transition-of-supercritical-oxygen-via-molecular-dynamics-simulations
#4
Abhinav S Raman, Huiyong Li, Y C Chiew
Supercritical oxygen, a cryogenic fluid, is widely used as an oxidizer in jet propulsion systems and is therefore of paramount importance in gaining physical insights into processes such as transcritical and supercritical vaporization. It is well established in the scientific literature that the supercritical state is not homogeneous but, in fact, can be demarcated into regions with liquid-like and vapor-like properties, separated by the "Widom line." In this study, we identified the Widom line for oxygen, constituted by the loci of the extrema of thermodynamic response functions (heat capacity, volumetric thermal expansion coefficient, and isothermal compressibility) in the supercritical region, via atomistic molecular dynamics simulations...
January 7, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29303272/comparative-analysis-of-small-molecule-diffusivity-in-different-fat-crystal-network
#5
Xiuhang Chai, Zong Meng, Peirang Cao, Jiang Jiang, Yuanfa Liu
Oil migration and fat recrystallization in fat-structured food materials can result in significant deterioration in food quality. Consequently, it is important to monitor and quantify the diffusivities of the migrants in fat crystal network. The diffusion coefficients of Nile red dye in liquid oils through fully hydrogenated palm kernel oil (FHPKO) / triolein (OOO) and fully hydrogenated soybean oil (FHSO) / triolein (OOO) systems were evaluated by the fluorescence recovery after photobleaching (FRAP) method...
January 5, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29297284/automated-classification-and-characterization-of-the-mitotic-spindle-following-knockdown-of-a-mitosis-related-protein
#6
Matloob Khushi, Imraan M Dean, Erdahl T Teber, Megan Chircop, Jonathan W Arthur, Neftali Flores-Rodriguez
BACKGROUND: Cell division (mitosis) results in the equal segregation of chromosomes between two daughter cells. The mitotic spindle plays a pivotal role in chromosome alignment and segregation during metaphase and anaphase. Structural or functional errors of this spindle can cause aneuploidy, a hallmark of many cancers. To investigate if a given protein associates with the mitotic spindle and regulates its assembly, stability, or function, fluorescence microscopy can be performed to determine if disruption of that protein induces phenotypes indicative of spindle dysfunction...
December 28, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/29289050/the-fractal-geometry-of-hartree-fock
#7
Friethjof Theel, Antonia Karamatskou, Robin Santra
The Hartree-Fock method is an important approximation for the ground-state electronic wave function of atoms and molecules so that its usage is widespread in computational chemistry and physics. The Hartree-Fock method is an iterative procedure in which the electronic wave functions of the occupied orbitals are determined. The set of functions found in one step builds the basis for the next iteration step. In this work, we interpret the Hartree-Fock method as a dynamical system since dynamical systems are iterations where iteration steps represent the time development of the system, as encountered in the theory of fractals...
December 2017: Chaos
https://www.readbyqxmd.com/read/29281811/enhanced-dewaterability-of-sludge-during-anaerobic-digestion-with-thermal-hydrolysis-pretreatment-new-insights-through-structure-evolution
#8
Jingsi Zhang, Ning Li, Xiaohu Dai, Wenquan Tao, Ian R Jenkinson, Zhuo Li
Comprehensive insights into the sludge digestate dewaterability were gained through porous network structure of sludge. We measured the evolution of digestate dewaterability, represented by the solid content of centrifugally dewatered cake, in high-solids sequencing batch digesters with and without thermal hydrolysis pretreatment (THP). The results show that the dewaterability of the sludge after digestion was improved by 3.5% (±0.5%) for unpretreated sludge and 5.1% (±0.4%) for thermally hydrolyzed sludge...
December 19, 2017: Water Research
https://www.readbyqxmd.com/read/29277050/combining-autohydrolysis-and-ionic-liquid-microwave-treatment-to-enhance-enzymatic-hydrolysis-of-eucalyptus-globulus-wood
#9
Victoria Rigual, Tamara M Santos, Juan Carlos Domínguez, M Virginia Alonso, Mercedes Oliet, Francisco Rodriguez
The combination of autohydrolysis and ionic liquid microwave treatments of eucalyptus wood have been studied to facilitate sugar production in a subsequent enzymatic hydrolysis step. Three autohydrolysis conditions (150 °C, 175 °C and 200 °C) in combination with two ionic liquid temperatures (80 °C and 120 °C) were compared in terms of chemical composition, enzymatic digestibility and sugar production. Morphology was measured (using SEM) and the biomass surface was visualized with confocal fluorescence microscopy...
December 14, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29249572/the-changes-in-classical-and-nonlinear-parameters-after-a-maximal-bout-to-elicit-fatigue-in-competitive-swimming
#10
Tiago M Barbosa, Simin Chen, Jorge E Morais, Mário J Costa, Nuno Batalha
The aim was to assess the effect of fatigue on linear and nonlinear parameters in swimming. Twenty-four fitness-oriented swimmers performed a maximal bout of 100 m at front-crawl to elicit fatigue. Before (pre-) and immediately after (post-test) the bout, participants swam an all-out 25 m to derive the speed fluctuation (dv), approximate entropy (ApEn) and fractal dimension (FD) from the speed-time series collected by a speedo-meter. Swim speed was 10.85% slower in the post-test than in the pre-test (p < ...
December 15, 2017: Human Movement Science
https://www.readbyqxmd.com/read/29249023/cortical-fractal-analysis-and-collagen-crosslinks-content-in-femoral-neck-after-osteoporotic-fracture-in-postmenopausal-women-comparison-with-osteoarthritis
#11
Gustavo Davi Rabelo, Jean-Paul Roux, Nathalie Portero-Muzy, Evelyne Gineyts, Roland Chapurlat, Pascale Chavassieux
The femoral neck (FN) has been previously characterized by thinner cortices in osteoporotic fracture (HF) when compared to hip osteoarthritis (HOA). The purposes of this study were to complete the previous investigations on FNs from HF and HOA by analyzing the complexity of the cortical structure and to approach the intrinsic properties of cortical bone by assessing the collagen crosslink contents. FN samples were obtained during arthroplasty in 35 postmenopausal women (HF; n = 17; mean age 79 ± 2 years; HOA; n = 18; mean age 66 ± 2 years)...
December 16, 2017: Calcified Tissue International
https://www.readbyqxmd.com/read/29247886/microcalcification-morphological-descriptors-and-parenchyma-fractal-dimension-hierarchically-interact-in-breast-cancer-a-diagnostic-perspective
#12
Garima Verma, Maria Laura Luciani, Alessandro Palombo, Linda Metaxa, Giovanna Panzironi, Federica Pediconi, Alessandro Giuliani, Mariano Bizzarri, Virginia Todde
INTRODUCTION: Herein, we propose a Systems Biology approach aimed at identifying quantitative morphological parameters useful in discriminating benign from malignant breast microcalcifications at digital mammography. MATERIALS AND METHODS: The study includes 31 patients in which microcalcifications had been detected during XR mammography and were further confirmed by stereotactic (XR-guided) biopsies. Patients were classified according to the BIRADS (Breast Imaging-Reporting and Data System), along with their parenchyma fractal dimension and biopsy size...
December 11, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29242621/fractal-analysis-of-collision-cascades-in-pulsed-ion-beam-irradiated-solids
#13
J B Wallace, L B Bayu Aji, L Shao, S O Kucheyev
The buildup of radiation damage in ion-irradiated crystals often depends on the spatial distribution of atomic displacements within collision cascades. Although collision cascades have previously been described as fractals, the correlation of their fractal parameters with experimental observations of radiation damage buildup remains elusive. Here, we use a pulsed-ion-beam method to study defect interaction dynamics in 3C-SiC irradiated at 100 °C with ions of different masses. These data, together with results of previous studies of SiC and Si, are analyzed with a model of radiation damage formation which accounts for the fractal nature of collision cascades...
December 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29241460/fractal-analysis-of-left-ventricular-trabeculations-is-associated-with-impaired-myocardial-deformation-in-healthy-chinese
#14
Jiashen Cai, Jennifer Ann Bryant, Thu-Thao Le, Boyang Su, Antonio de Marvao, Declan P O'Regan, Stuart A Cook, Calvin Woon-Loong Chin
BACKGROUND: Left ventricular (LV) non-compaction (LVNC) is defined by extreme LV trabeculation, but is measured variably. Here we examined the relationship between quantitative measurement in LV trabeculation and myocardial deformation in health and disease and determined the clinical utility of semi-automated assessment of LV trabeculations. METHODS: Cardiovascular magnetic resonance (CMR) was performed in 180 healthy Singaporean Chinese (age 20-69 years; males, n = 91), using balanced steady state free precession cine imaging at 3T...
December 14, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29240141/quantification-of-laser-induced-damage-growth-using-fractal-analysis
#15
Matthieu Veinhard, Odile Bonville, Roger Courchinoux, Romain Parreault, Jean-Yves Natoli, Laurent Lamaignère
Lateral and longitudinal laser damage growth under subsequent irradiations at 351 nm in the nanosecond range from micrometric to millimetric scales is presented herein. Atypical behavior has been observed, showing the growth in the longitudinal direction, whereas the lateral growth does not evolve. We propose the use of fractal analysis to describe the evolution of the bulk damage morphology. The results indicate first a dependence between the damage fractal dimension and the laser parameters, such as the fluence and the pulse duration...
December 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29239394/quantitative-mr-image-analysis-for-brian-tumor
#16
Zeina A Shboul, Sayed M S Reza, Khan M Iftekharuddin
This paper presents an integrated quantitative MR image analysis framework to include all necessary steps such as MRI inhomogeneity correction, feature extraction, multiclass feature selection and multimodality abnormal brain tissue segmentation respectively. We first obtain mathematical algorithm to compute a novel Generalized multifractional Brownian motion (GmBm) texture feature. We then demonstrate efficacy of multiple multiresolution texture features including regular fractal dimension (FD) texture, and stochastic texture such as multifractional Brownian motion (mBm) and GmBm features for robust tumor and other abnormal tissue segmentation in brain MRI...
2018: VipIMAGE 2017 (2017)
https://www.readbyqxmd.com/read/29230678/fractal-based-radiomic-approach-to-predict-complete-pathological-response-after-chemo-radiotherapy-in-rectal-cancer
#17
Davide Cusumano, Nicola Dinapoli, Luca Boldrini, Giuditta Chiloiro, Roberto Gatta, Carlotta Masciocchi, Jacopo Lenkowicz, Calogero Casà, Andrea Damiani, Luigi Azario, Johan Van Soest, Andre Dekker, Philippe Lambin, Marco De Spirito, Vincenzo Valentini
The aim of this study was to propose a methodology to investigate the tumour heterogeneity and evaluate its ability to predict pathologically complete response (pCR) after chemo-radiotherapy (CRT) in locally advanced rectal cancer (LARC). This approach consisted in normalising the pixel intensities of the tumour and identifying the different sub-regions using an intensity-based thresholding. The spatial organisation of these subpopulations was quantified using the fractal dimension (FD). This approach was implemented in a radiomic workflow and applied to 198 T2-weighted pre-treatment magnetic resonance (MR) images of LARC patients...
December 11, 2017: La Radiologia Medica
https://www.readbyqxmd.com/read/29220357/difference-of-the-progression-of-pulmonary-cysts-assessed-by-computed-tomography-among-copd-lymphangioleiomyomatosis-and-birt-hogg-dub%C3%A3-syndrome
#18
Kazunori Tobino, Toyohiro Hirai, Takeshi Johkoh, Kiminori Fujimoto, Atsushi Kawaguchi, Noriyuki Tomiyama, Kazuhisa Takahashi, Kuniaki Seyama
Many groups developed the methods to quantitatively analyze low attenuation area (LAA) on chest CT in patients with cystic lung diseases. Especially in COPD, it was reported that the cumulative size distribution of LAA clusters follows a power law characterized by the exponent D, which reflect the fractal dimension of terminal airspace geometry. We hypoyhesized that the quantitative charateristics of LAA clusters including fractal property might indicate the different features of the progression of cysts in cystic lung diseases...
2017: PloS One
https://www.readbyqxmd.com/read/29219460/oxidation-mediated-fingering-in-liquid-metals
#19
Collin B Eaker, David C Hight, John D O'Regan, Michael D Dickey, Karen E Daniels
We identify and characterize a new class of fingering instabilities in liquid metals; these instabilities are unexpected due to the large interfacial tension of metals. Electrochemical oxidation lowers the effective interfacial tension of a gallium-based liquid metal alloy to values approaching zero, thereby inducing drastic shape changes, including the formation of fractals. The measured fractal dimension (D=1.3±0.05) places the instability in a different universality class than other fingering instabilities...
October 27, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29216231/a-computational-model-to-investigate-the-effect-of-pennation-angle-on-surface-electromyogram-of-tibialis-anterior
#20
Diptasree Maitra Ghosh, Dinesh Kumar, Sridhar Poosapadi Arjunan, Ariba Siddiqi, Ramakrishnan Swaminathan
This study has described and experimentally validated the differential electrodes surface electromyography (sEMG) model for tibialis anterior muscles during isometric contraction. This model has investigated the effect of pennation angle on the simulated sEMG signal. The results show that there is no significant effect of pennation angle in the range 0° to 20° to the single fibre action potential shape recorded on the skin surface. However, the changes with respect to pennation angle are observed in sEMG amplitude, frequency and fractal dimension...
2017: PloS One
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