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https://www.readbyqxmd.com/read/28723846/value-of-fractal-analysis-of-optical-coherence-tomography-angiography-in-various-stages-of-diabetic-retinopathy
#1
Suruchi Bhardwaj, Edmund Tsui, Sarwar Zahid, Emma Young, Nitish Mehta, Steven Agemy, Patricia Garcia, Richard B Rosen, Joshua A Young
PURPOSE: To use fractal dimensional analysis to investigate retinal vascular disease patterns in patients with diabetic retinopathy using spectral domain optical coherence tomography angiography. METHODS: A retrospective study was conducted which included 49 eyes from 26 control subjects and 58 eyes from 35 patients known to have diabetic retinopathy. Of the 58 eyes with known retinopathy, 31 were categorized as nonproliferative diabetic retinopathy (13 mild, 9 moderate, and 9 severe) and 27 were categorized as proliferative diabetic retinopathy...
July 18, 2017: Retina
https://www.readbyqxmd.com/read/28717134/ash-production-by-attrition-in-volcanic-conduits-and-plumes
#2
T J Jones, J K Russell
Tephra deposits result from explosive volcanic eruption and serve as indirect probes into fragmentation processes operating in subsurface volcanic conduits. Primary magmatic fragmentation creates a population of pyroclasts through volatile-driven decompression during conduit ascent. In this study, we explore the role that secondary fragmentation, specifically attrition, has in transforming primary pyroclasts upon transport in volcanic conduits and plumes. We utilize total grain size distributions from a suite of natural and experimentally produced tephra to show that attrition is likely to occur in all explosive volcanic eruptions...
July 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28709262/coexisting-origins-of-subdiffusion-in-internal-dynamics-of-proteins
#3
Yasmine Meroz, Victor Ovchinnikov, Martin Karplus
Subdiffusion in conformational dynamics of proteins is observed both experimentally and in simulations. Although its origin has been attributed to multiple mechanisms, including trapping on a rugged energy landscape, fractional Brownian noise, or a fractal topology of the energy landscape, it is unclear which of these, if any, is most relevant. To obtain insights into the actual mechanism, we introduce an analytically tractable hierarchical trapping model and apply it to molecular dynamics simulation trajectories of three proteins in solution...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28709260/pneumatic-fractures-in-confined-granular-media
#4
Fredrik K Eriksen, Renaud Toussaint, Antoine L Turquet, Knut J Måløy, Eirik G Flekkøy
We perform experiments where air is injected at a constant overpressure P_{in}, ranging from 5 to 250 kPa, into a dry granular medium confined within a horizontal linear Hele-Shaw cell. The setup allows us to explore compacted configurations by preventing decompaction at the outer boundary, i.e., the cell outlet has a semipermeable filter such that beads are stopped while air can pass. We study the emerging patterns and dynamic growth of channels in the granular media due to fluid flow, by analyzing images captured with a high speed camera (1000 images/s)...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28709252/magnetorheological-response-of-highly-filled-magnetoactive-elastomers-from-perspective-of-mechanical-energy-density-fractal-aggregates-above-the-nanometer-scale
#5
Vladislav V Sorokin, Inna A Belyaeva, Mikhail Shamonin, Elena Yu Kramarenko
The dynamic shear modulus of magnetoactive elastomers containing 70 and 80 mass % of carbonyl iron microparticles is measured as a function of strain amplitude via dynamic torsion oscillations in various magnetic fields. The results are presented in terms of the mechanical energy density and considered in the framework of the conventional Kraus model. The form exponent of the Kraus model is further related to a physical model of Huber et al. [Huber et al., J. Phys.: Condens. Matter 8, 409 (1996)10.1088/0953-8984/8/29/003] that uses a realistic representation for the cluster network possessing fractal structure...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28709196/characterizing-time-series-via-complexity-entropy-curves
#6
Haroldo V Ribeiro, Max Jauregui, Luciano Zunino, Ervin K Lenzi
The search for patterns in time series is a very common task when dealing with complex systems. This is usually accomplished by employing a complexity measure such as entropies and fractal dimensions. However, such measures usually only capture a single aspect of the system dynamics. Here, we propose a family of complexity measures for time series based on a generalization of the complexity-entropy causality plane. By replacing the Shannon entropy by a monoparametric entropy (Tsallis q entropy) and after considering the proper generalization of the statistical complexity (q complexity), we build up a parametric curve (the q-complexity-entropy curve) that is used for characterizing and classifying time series...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28708390/softwood-lignin-self-assembly-for-nanomaterial-design
#7
Stefan Salentinig, Mark Schubert
Lignin is a natural, renewable biopolymer synthesized by plants. It is a macromolecule consisting of aromatic structures with high density of functional groups making it an ideal precursor for the design of sustainable biomaterials for applications such as drug delivery. The rational design of these materials requires an in-depth understanding of the underlying lignin self-assembly in solution. Colloidal transformations from nano-sized lignin assemblies to sub-micron sized spherical particles upon solvent exchange were studied using small angle X-ray scattering, dynamic light scattering and electron microscopy...
July 14, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28707523/strut-analyses-for-detecting-osteoporosis-using-dental-panoramic-radiography
#8
Jae Joon Hwang, Jeong-Hee Lee, Young Hyun Kim, Ho-Gul Jeong, Yoon Jeong Choi, Wonse Park, Sang-Sun Han
OBJECTIVES: The aim of this study was to identify variables that can be used for osteoporosis detection using strut analysis, fractal dimension (FD), and the gray level co-occurrence matrix (GLCM) using multiple regions of interest (ROIs) and to develop an osteoporosis detection model based on panoramic radiography. METHODS: A total of 454 panoramic radiographs from oral examinations in our dental hospital from 2012 to 2015 were randomly selected, equally distributed among osteoporotic and non-osteoporotic patients (n=227 in each group)...
July 14, 2017: Dento Maxillo Facial Radiology
https://www.readbyqxmd.com/read/28704694/harmony-as-a-convergence-attractor-that-minimizes-the-energy-expenditure-and-variability-in-physiological-gait-and-the-loss-of-harmony-in-cerebellar-ataxia
#9
Mariano Serrao, Giorgia Chini, Marco Iosa, Carlo Casali, Giovanni Morone, Carmela Conte, Fabiano Bini, Franco Marinozzi, Gianluca Coppola, Francesco Pierelli, Francesco Draicchio, Alberto Ranavolo
BACKGROUND: The harmony of the human gait was recently found to be related to the golden ratio value (ϕ). The ratio between the duration of the stance and that of the swing phases of a gait cycle was in fact found to be close to ϕ, which implies that, because of the fractal property of autosimilarity of that number, the gait ratios stride/stance, stance/swing, swing/double support, were not significantly different from one another. We studied a group of patients with cerebellar ataxia to investigate how the differences between their gait ratios and the golden ratio are related to efficiency and stability of their gait, assessed by energy expenditure and stride-to-stride variability, respectively...
July 5, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/28704515/structural-characterization-of-chaos-game-fractals-using-small-angle-scattering-analysis
#10
Eugen Mircea Anitas, Azat Slyamov
Small-angle scattering (SAS) technique is applied to study the nano and microstructural properties of spatial patterns generated from chaos game representation (CGR). Using a simplified version of Debye formula, we calculate and analyze in momentum space, the monodisperse scattering structure factor from a system of randomly oriented and non-interacting 2D Sierpinski gaskets (SG). We show that within CGR approach, the main geometrical and fractal properties, such as the overall size, scaling factor, minimal distance between scattering units, fractal dimension and the number of units composing the SG, can be recovered...
2017: PloS One
https://www.readbyqxmd.com/read/28704031/supported-dendrimer-encapsulated-metal-clusters-toward-heterogenizing-homogeneous-catalysts
#11
Rong Ye, Aleksandr V Zhukhovitskiy, Christophe V Deraedt, F Dean Toste, Gabor A Somorjai
Recyclable catalysts, especially those that display selective reactivity, are vital for the development of sustainable chemical processes. Among available catalyst platforms, heterogeneous catalysts are particularly well-disposed toward separation from the reaction mixture via filtration methods, which renders them readily recyclable. Furthermore, heterogeneous catalysts offer numerous handles-some without homogeneous analogues-for performance and selectivity optimization. These handles include nanoparticle size, pore profile of porous supports, surface ligands and interface with oxide supports, and flow rate through a solid catalyst bed...
July 13, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28702370/in-vitro-and-in-silico-characterization-of-metagenomic-soil-derived-cellulases-capable-of-hydrolyzing-oil-palm-empty-fruit-bunch
#12
Laura Marcela Palma Medina, Diana Catalina Ardila, María Mercedes Zambrano, Silvia Restrepo, Andrés Fernando González Barrios
Diversification of raw material for biofuel production is of interest to both academia and industry. One attractive substrate is a renewable lignocellulosic material such as oil palm (Elaeis guineensis Jacq.) empty fruit bunch (OPEFB), which is a byproduct of the palm oil industry. This study aimed to characterize cellulases active against this substrate. Cellulases with activity against OPEFB were identified from a metagenomic library obtained from DNA extracted from a high-Andean forest ecosystem. Our findings show that the highest cellulolytic activities were obtained at pH and temperature ranges of 4-10 and 30 °C-60 °C, respectively...
September 2017: Biotechnology Reports
https://www.readbyqxmd.com/read/28700136/an-automated-framework-to-quantify-areas-of-regional-ischemia-in-retinal-vascular-diseases-with-oct-angiography
#13
Neha Anegondi, Lavanya Chidambara, Devanshi Bhanushali, Santosh G K Gadde, Naresh Kumar Yadav, Abhijit Sinha Roy
In this observational and cross-sectional study, capillary non perfusion (CNP) and vascular changes in branch retinal vein occlusion (BRVO, sample size (n) = 26) and choroidal neovascularization (CNV, n = 29) were evaluated. Subjects underwent imaging using Optical coherence tomography angiography (Angiovue™ OCTA , RTVue XR, Optovue Inc., Fremont, CA). Local fractal analysis was applied to the OCTA images of superficial, deep and choriocapillaries layer. CNP area (BRVO eyes) and vascular parameters were computed using local fractal based method...
July 12, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28693100/a-contact-angle-hysteresis-model-based-on-the-fractal-structure-of-contact-line
#14
Shuai Wu, Ming Ma
Contact angle is one of the most popular concept used in fields such as wetting, transport and microfludics. In practice, different contact angles such as equilibrium, receding and advancing contact angles are observed due to hysteresis. The connection among these contact angles is important in revealing the chemical and physical properties of surfaces related to wetting. Inspired by the fractal structure of contact line, we propose a single parameter model depicting the connection of the three angles. This parameter is decided by the fractal structure of the contact line...
June 27, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28691721/nonlinear-dynamics-analysis-of-the-human-balance-control-subjected-to-physical-and-sensory-perturbations
#15
Mohammed N Ashtiani, Azghani Mahmood-Reza
Postural control after applying perturbation involves neural and muscular efforts to limit the center of mass (CoM) motion. Linear dynamical approaches may not unveil all complexities of body efforts. This study was aimed at determining two nonlinear dynamics parameters (fractal dimension (FD) and largest Lyapunov exponent (LLE)) in addition to the linear standing metrics of balance in perturbed stance. Sixteen healthy young males were subjected to sudden rotations of the standing platform. The vision and cognition during the standing were also interfered...
2017: Acta Neurobiologiae Experimentalis
https://www.readbyqxmd.com/read/28690919/plasma-membrane-is-compartmentalized-by-a-self-similar-cortical-actin-meshwork
#16
Sanaz Sadegh, Jenny L Higgins, Patrick C Mannion, Michael M Tamkun, Diego Krapf
A broad range of membrane proteins display anomalous diffusion on the cell surface. Different methods provide evidence for obstructed subdiffusion and diffusion on a fractal space, but the underlying structure inducing anomalous diffusion has never been visualized because of experimental challenges. We addressed this problem by imaging the cortical actin at high resolution while simultaneously tracking individual membrane proteins in live mammalian cells. Our data confirm that actin introduces barriers leading to compartmentalization of the plasma membrane and that membrane proteins are transiently confined within actin fences...
January 2017: Physical Review. X
https://www.readbyqxmd.com/read/28684850/the-role-of-city-size-and-urban-form-in-the-surface-urban-heat-island
#17
Bin Zhou, Diego Rybski, Jürgen P Kropp
Urban climate is determined by a variety of factors, whose knowledge can help to attenuate heat stress in the context of ongoing urbanization and climate change. We study the influence of city size and urban form on the Urban Heat Island (UHI) phenomenon in Europe and find a complex interplay between UHI intensity and city size, fractality, and anisometry. Due to correlations among these urban factors, interactions in the multi-linear regression need to be taken into account. We find that among the largest 5,000 cities, the UHI intensity increases with the logarithm of the city size and with the fractal dimension, but decreases with the logarithm of the anisometry...
July 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28679066/agro-waste-biosorbents-effect-of-physico-chemical-properties-on-atrazine-and-imidacloprid-sorption
#18
Abhishek Mandal, Neera Singh, Lata Nain
Low cost agro-waste biosorbents namely eucalyptus bark (EB), corn cob (CC), bamboo chips (BC), rice straw (RS) and rice husk (RH) were characterized and used to study atrazine and imidacloprid sorption. Adsorption studies suggested that biosorbents greatly varied in their pesticide sorption behaviour. The EB was the best biosorbent to sorb both atrazine and imidacloprid with KF values of 169.9 and 85.71, respectively. The adsorption isotherm were nonlinear in nature with slope (1/n) values <1. The Freundlich constant Correlating atrazine/imidacloprid sorption parameter [KF...
July 5, 2017: Journal of Environmental Science and Health. Part. B, Pesticides, Food Contaminants, and Agricultural Wastes
https://www.readbyqxmd.com/read/28675772/constructing-high-generation-of-sierpinski-triangles-with-molecular-puzzling
#19
Pingshan Wang, Zhilong Jiang, Yiming Li, Ming Wang, Die Liu, Jie Yuan, Mingzhao Chen, George R Newkome, Wei Sun, Xiaopeng Li
As a fractal geometry, Sierpinski triangle has attracted increasing attention in science, technology, engineering, math and art. Herein, three generations of metallo-trigonal supramolecular architectures, metallo-triangles, were assembled using terpyridine (tpy) complexes. The first generation (G1) of mononuclear metallo-triangle was directly obtained by reacting a 60o-orientated bisterpyridinyl ligand and Zn(II) ion. A modular strategy based on the connectivity of <tpy-Ru(II)-tpy> was employed to construct two predesigned metallo-organic ligands for the assemblies of the second and third generations (G2 and G3) of Sierpiński triangles...
July 4, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28671629/motor-imagery-eeg-classification-for-patients-with-amyotrophic-lateral-sclerosis-using-fractal-dimension-and-fisher-s-criterion-based-channel-selection
#20
Yi-Hung Liu, Shiuan Huang, Yi-De Huang
Motor imagery is based on the volitional modulation of sensorimotor rhythms (SMRs); however, the sensorimotor processes in patients with amyotrophic lateral sclerosis (ALS) are impaired, leading to degenerated motor imagery ability. Thus, motor imagery classification in ALS patients has been considered challenging in the brain-computer interface (BCI) community. In this study, we address this critical issue by introducing the Grassberger-Procaccia and Higuchi's methods to estimate the fractal dimensions (GPFD and HFD, respectively) of the electroencephalography (EEG) signals from ALS patients...
July 3, 2017: Sensors
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