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fractal dimension

Dongmei Li Cuiru Wu Yizhi Wang Shuxian Jiang Shaoxiu Li Jinling Liang Wen Zhang
To improve the removal efficiency of micro-pollutant humic acid (HA) at low temperature, micro-flocculation filtrationexperiments were conducted with homemade iron oxide amended sands (IOAS), cationic polyelectrolyte (CP) and polyaluminium chloride (PACl). Fractal properties of flocs structures and IOAS surface and their effects on the removal efficiency of HA were investigated. Results showed that IOAS had a porous surface with fractal dimensions (D=1.744) and a strong adsorption capacity for HA. The flocs produced by PACl were small in size, loosely packed with a higher D, and therefore settled slowly...
March 14, 2017: Water Environment Research: a Research Publication of the Water Environment Federation
Jeroen Van Dessel, Laura Ferreira Pinheiro Nicolielo, Yan Huang, Walter Coudyzer, Benjamin Salmon, Ivo Lambrichts, Reinhilde Jacobs
OBJECTIVE: The aim of this study was to assess whether cone beam computed tomography (CBCT) may be used for clinically reliable alveolar bone quality assessment in comparison to its clinical alternatives, multislice computed tomography and the gold standard (micro-CT). MATERIALS AND METHODS: Six dentate mandibular bone samples were scanned with seven CBCT devices (ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170, Carestream 9300, Scanora 3D, I-CAT Next generation), one micro-CT scanner (SkyScan 1174) and one MSCT machine (Somatom Definition Flash) using two protocols (standard and high-resolution)...
2017: European Journal of Oral Implantology
Lucietta Betti, Grazia Trebbi, Maria Olga Kokornaczyk, Daniele Nani, Maurizio Peruzzi, Giovanni Dinelli, Paolo Bellavite, Maurizio Brizzi
OBJECTIVES: The aim of this study is to investigate whether the number of succussion strokes applied after each dilution step when preparing the homeopathic treatments influences the effectiveness of ultra-high-diluted (UHD) arsenic trioxide at the 45th decimal dilution/dynamization (As2O3 45x). DESIGN: Wheat seeds, previously stressed with ponderal As2O3, were treated with: As2O3 45x, H2O 45x (dynamized control), or pure water (negative control). The succussion was done manually, and various succussion durations (numbers of strokes) were tested for each treatment...
February 2017: Homeopathy: the Journal of the Faculty of Homeopathy
John M O'Toole, Mmoloki Kenosi, Daragh Finn, Geraldine B Boylan, Eugene M Dempsey
Babies born prematurely can develop brain injury within days after birth. Early identification of high-risk infants enables appropriate clinical care to mitigate potential lifelong disabilities. Near infra-red spectroscopy is an established technology that can provide continuous measurements of cerebral oxygen saturation (rcSO2) over this critical period. We develop a feature set of the rcSO2 signal for the purpose of detecting brain injury. Our feature set contains amplitude, spectral, and fractal dimension features within 5 frequency bands...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Igor Nenadic, Rachel A Yotter, Maren Dietzek, Kerstin Langbein, Heinrich Sauer, Christian Gaser
Recent studies using surface-based morphometry of structural magnetic resonance imaging data have suggested that some changes in bipolar disorder (BP) might be neurodevelopmental in origin. We applied a novel analysis of cortical complexity based on fractal dimensions in high-resolution structural MRI scans of 18 bipolar disorder patients and 26 healthy controls. Our region-of-interest based analysis revealed increases in fractal dimensions (in patients relative to controls) in left lateral orbitofrontal cortex and right precuneus, and decreases in right caudal middle frontal, entorhinal cortex, and right pars orbitalis, and left fusiform and posterior cingulate cortices...
February 21, 2017: Psychiatry Research
Mary Woods, John B Williamson, Keith D White, Charles G Maitland, Kenneth M Heilman
BACKGROUND AND OBJECTIVE: Many patients who have signs of neglect immediately after a right hemisphere stroke remain disabled even when they improve on tests of neglect. Few patients are tested for attentional persistence and fatigue despite their importance in many instrumental activities. To investigate whether stimulus repetition might alter the allocation of attention, we repeatedly tested a patient 16 weeks after she developed hemispatial neglect from a right hemisphere stroke. METHODS: During each of three testing sessions given in 1 day, we asked the patient to bisect 90 lines of two lengths, presented in 30-trial blocks in three locations: left, center, and right of her midsagittal plane, partially counterbalanced across sessions...
March 2017: Cognitive and Behavioral Neurology: Official Journal of the Society for Behavioral and Cognitive Neurology
Akihito Uji, Siva Balasubramanian, Jianqin Lei, Elmira Baghdasaryan, Mayss Al-Sheikh, SriniVas R Sadda
PURPOSE: To investigate the impact of multiple en face image averaging on quantitative measurements of the retinal microvasculature using optical coherence tomography angiography (OCTA). DESIGN: Prospective, observational, cross-sectional case series. PARTICIPANTS: Twenty-one healthy individuals with normal eyes. METHODS: Macular OCTA images were acquired from all participants using the Zeiss Cirrus 5000 with Angioplex OCTA software (Carl Zeiss Meditec, Dublin, CA)...
March 16, 2017: Ophthalmology
Yusong Deng, Chongfa Cai, Dong Xia, Shuwen Ding, Jiazhou Chen
Collapsing gullies are among the most severe soil erosion problems in the tropical and subtropical areas of southern China. However, few studies have examined the relationship of soil particle size distribution (PSD) changes with land-use patterns in the alluvial fans of collapsing gullies. Recently, the fractal method has been applied to estimate soil structure and has proven to be an effective tool in analyzing soil properties and their relationships with other eco-environmental factors. In this study, the soil fractal dimension (D), physico-chemical properties and their relationship with different land-use patterns in alluvial fans were investigated in an experiment that involved seven collapsing gully areas in seven counties of southern China...
2017: PloS One
Mani Fathali, Saber Khoei
Time evolution of the fully resolved incompressible homogeneous turbulent shear flow in noninteger Fourier dimensions is numerically investigated. The Fourier dimension of the flow field is extended from the integer value 3 to the noninteger values by projecting the Navier-Stokes equation on the fractal set of the active Fourier modes with dimensions 2.7≤d≤3.0. The results of this study revealed that the dynamics of both large and small scale structures are nontrivially influenced by changing the Fourier dimension d...
February 2017: Physical Review. E
M Borgnino, F De Lillo, G Boffetta
We study the small scale clustering of gyrotactic swimmers transported by a turbulent flow, when the intrinsic variability of the swimming parameters within the population is considered. By means of extensive numerical simulations, we find that the variety of the population introduces a characteristic scale R^{*} in its spatial distribution. At scales smaller than R^{*} the swimmers are homogeneously distributed, while at larger scales an inhomogeneous distribution is observed with a fractal dimension close to what observed for a monodisperse population characterized by mean parameters...
February 2017: Physical Review. E
T A Sobral, M A F Gomes
The continuous packing of a flexible rod in two-dimensional cavities yields a countable set of interacting domains that resembles nonequilibrium cellular systems and belongs to a new class of lightweight material. However, the link between the length of the rod and the number of domains requires investigation, especially in the case of non-simply connected cavities, where the number of avoided regions emulates an effective topological temperature. In the present article we report the results of an experiment of injection of a single flexible rod into annular cavities in order to find the total length needed to insert a given number of loops (domains of one vertex)...
February 2017: Physical Review. E
Jiazhou Wang, Xiance Jin, Jiayuan Peng, Jiang Xie, Junchao Chen, Weigang Hu
This study investigated the impact of beam complexities on planar quality assurance and plan quality robustness by introducing MLC errors in intensity-modulate radiation therapy. Forty patients' planar quality assurance (QA) plans were enrolled in this study, including 20 dynamic MLC (DMLC) IMRT plans and 20 static MLC (SMLC) IMRT plans. The total beam numbers were 150 and 160 for DMLC and SMLC, respectively. Six different magnitudes of MLC errors were introduced to these beams. Gamma pass rates were calculated by comparing error-free fluence and error-induced fluence...
May 2016: Journal of Applied Clinical Medical Physics
Shahin Zandieh, Joerg Haller, Reinhard Bernt, Klaus Hergan, Eva Rath
Rheumatoid arthritis (RA) is a chronic and systemic inflammatory disorder. Conventional radiography, a widely available and cost-effective examination method, remains the standard of reference for the detection and quantification of joint involvement in RA. Fractal dimension (FD) of the trabecular bone structure has been proven to correlate with the bone's physical properties. The present study was designed to use fractal analysis to validate radiograph changes in the hand of RA patients.This study retrospectively evaluated the hand radiographs of 108 subjects...
March 2017: Medicine (Baltimore)
Huaqing Liang, Matthew Beerse, Xiang Ke, Jianhua Wu
Whole body vibration (WBV) can affect postural control and muscular activation. The purpose of this study was to investigate the center-of-mass (COM) movement of children and young adults before, during, immediately after, and 5min after 40-s WBV in quiet standing. Fourteen young adults (mean age 24.5 years) and fourteen children (mean age 8.1 years) participated in the study. A full-body 35-marker set was placed on the participants and used to calculate COM. Forty-second standing trials were collected before, during, immediately after, and 5min after WBV with an frequency of 28Hz and an amplitude of <1mm...
March 8, 2017: Gait & Posture
Premkumar Elangovan, Alistair Mackenzie, David R Dance, Kenneth C Young, Victoria Cooke, Louise Wilkinson, Rosalind M Given-Wilson, Matthew G Wallis, Kevin Wells
A novel method has been developed for generating quasi-realistic voxel phantoms which simulate the compressed breast in mammography and digital breast tomosynthesis (DBT). The models are suitable for use in virtual clinical trials requiring realistic anatomy which use the multiple alternative forced choice (AFC) paradigm and patches from the complete breast image. The breast models are produced by extracting features of breast tissue components from DBT clinical images including skin, adipose and fibro-glandular tissue, blood vessels and Cooper's ligaments...
April 7, 2017: Physics in Medicine and Biology
Mu Huang, Zhouzhou Liu, Aimin Li, Hu Yang
In this work, a series of quaternary ammonium salt grafted starch flocculant, starch-graft-poly(2-methacryloyloxyethyl) trimethyl ammonium chloride (St-g-PDMC), with different grafting ratios was prepared by a simple method. Various characterization techniques were employed to investigate the structure and charge property of the starch-based flocculants. The efficiencies of St-g-PDMC for flocculation of kaolin and Escherichia coli suspensions as well as their mixtures were systematically examined in laboratory scale...
March 8, 2017: Journal of Environmental Management
Maria N Starodubtseva, Ivan E Starodubtsev, Evgenii G Starodubtsev
Fractal dimension (DF) is one of the important parameters in the description of object's properties in different fields including biology and medicine. The present paper is focused on the application of the fractal dimension (the box counting dimension) in the analysis of the properties of cell surface on the base of its images obtained by atomic force microscopy (AFM). Fractal dimension of digital 3D AFM images depends on interpoint distances determined by the scanning step in the XY-plane and Z-scale factor t...
February 28, 2017: Micron: the International Research and Review Journal for Microscopy
Qian Xu, Yuxiang Dong, Ren Yang
This study analyzed carbon fixation across different land use types in the Pearl River Delta to identify the influence of different geographical factors on carbon fixation ability. The methodology was based on interpreting land use data from TM imagery, MODIS13Q1 data, and climate data, using the improved CASA and GeogDetector models. The results show that: (1) From 2000 to 2013, the total carbon sink increased slightly, from 15.58 × 10(6) t to 17.52 × 10(6) t, being spatially low at the center and increasing outwards; (2) Proxy variables (topography and landform characteristics), influencing urbanization, significantly affect the carbon sink function of the Pearl River Delta region...
December 2017: Scientific Reports
Manouane Caza-Szoka, Daniel Massicotte, Francois Nougarou, Martin Descarreaux
In this paper, a method based on nonlinear analysis of sEMG sensor array signals (2 arrays of 5×13 sensors) to detect chronic low back pain is presented. The use of an FFT based surrogate analysis method isolates the nonlinear structure of the signals from the effect of the power spectrum. The fractal dimension is used for the nonlinear characteristic. From the sensor arrays, a certain number of channels which exhibits the most nonlinearity for a subject are kept as input of a small neural network. A leave-one-out type cross-validation method shows a success rate of 80%...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
A Leal, R Couceiro, I Chouvarda, N Maglaveras, J Henriques, R Paiva, P Carvalho, C Teixeira
Lung sound signal processing has proven to be a great improvement to the traditional acoustic interpretation of lung sounds. However, that analysis can be seriously hindered by the presence of different types of noise originated in the acquisition environment or caused by physiological processes. Consequently, the diagnostic accuracy of pulmonary diseases can be severely affected, especially if the implementation of telemonitoring systems is considered. The present study is focused on the implementation of an algorithm able to identify noisy periods, either voluntarily (vocalizations, chest movement and background voices) or involuntarily produced during acquisitions of lung sounds...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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