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Felix Sebastian Leo Thomsen, Jaime Andrés Peña, Yongtao Lu, Gerd Huber, Michael Morlock, Claus-Christian Glüer, Claudio Augusto Delrieux
PURPOSE: Existing microstructure parameters are able to predict vertebral in vitro failure load, but for noisy in vivo data more complex algorithms are needed for a robust assessment. METHODS: A new algorithm is proposed for the microstructural analysis of trabecular bone under in vivo quantitative computed tomography (QCT). Five fractal parameters are computed: (1) the average local fractal dimension FD, (2) its standard deviation FD.SD, (3) the fractal rod volume ratio fRV/BV, (4) the average fractal trabecular thickness fTb...
December 2016: Medical Physics
Lei Zhang
The phaseless inverse scattering of optical or electromagnetic waves from unbounded fractally corrugated surfaces are taken into account. The main characteristics of this inverse scattering problem are that only the phaseless scattered field is measured and the incident field is a tapered wave. In the previous recent works of the authors about the inverse scattering of rough surfaces, the cases of the Dirichlet boundary condition were considered [Inverse Prob.32, 085002 (2016)INPEEY0266-561110.1088/0266-5611/32/8/085002; Inverse Probl...
December 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Haitao Fan, Xiuhong Liu, Hao Wang, Yunping Han, Lu Qi, Hongchen Wang
In activated sludge systems, the aeration process consumes the most energy. The energy cost can be dramatically reduced by decreasing the operating dissolved oxygen (DO) concentration. However, low DO may lead to incomplete nitrification and poor settling performance of activated sludge flocs (ASFs). This study investigates oxygen transfer dynamics and settling performances of activated sludge under different sludge retention times (SRTs) and DO conditions using microelectrodes and microscopic techniques. Our experimental results showed that with longer SRTs, treatment capacity and settling performances of activated sludge improved due to smaller floc size and less extracellular polymeric substances (EPS)...
November 27, 2016: Chemosphere
Somayeh Raiesdana
It is thought that the critical brain dynamics in sleep is modulated during frequent periods of wakefulness. This paper utilizes the capacity of EEG based scaling analysis to quantify sleep fragmentation in patients with obstructive sleep apnea. The scale-free (fractal) behavior refers to a state where no characteristic scale dominates the dynamics of the underlying process which is evident as long range correlations in a time series. Here, Multiscaling (multifractal) spectrum is utilized to quantify the disturbed dynamic of an OSA brain with fragmented sleep...
November 18, 2016: Technology and Health Care: Official Journal of the European Society for Engineering and Medicine
Yi Yu, Yun Zhao, Yajing Si, Qiongqiong Ren, Wu Ren, Changqin Jing, Hongxing Zhang
BACKGROUND: In schizophrenia, executive dysfunction is the most critical cognitive impairment, and is associated with abnormal neural activities, especially in the frontal lobes. Complexity estimation using electroencephalogram (EEG) recording based on nonlinear dynamics and task performance tests have been widely used to estimate executive dysfunction in schizophrenia. METHODS: The present study estimated the cool executive function based on fractal dimension (FD) values of EEG data recorded from first-episode schizophrenia patients and healthy controls during the performance of three cool executive function tasks, namely, the Trail Making Test-A (TMT-A), Trail Making Test-B (TMT-B), and Tower of Hanoi tasks...
November 25, 2016: Biomedical Engineering Online
Guoxing Lin
Anomalous diffusion exists widely in polymer and biological systems. Pulsed-field gradient (PFG) techniques have been increasingly used to study anomalous diffusion in nuclear magnetic resonance and magnetic resonance imaging. However, the interpretation of PFG anomalous diffusion is complicated. Moreover, the exact signal attenuation expression including the finite gradient pulse width effect has not been obtained based on fractional derivatives for PFG anomalous diffusion. In this paper, a new method, a Mainardi-Luchko-Pagnini (MLP) phase distribution approximation, is proposed to describe PFG fractional diffusion...
November 21, 2016: Journal of Chemical Physics
R G Hall, J G Pasipanodya, C Meek, R D Leff, M Swancutt, T Gumbo
Trimethoprim-sulfamethoxazole (TMP-SMX) is one of the most widely drugs on earth. The World Health Organization recommends it as an essential basic drug for all healthcare systems. Dosing is inconsistently based on weight, assuming linear relationships. Given that obesity is now a global "pandemic" it is vital that we evaluate the effect of obesity on trimethoprim-sulfamethoxazole concentrations. We conducted a prospective clinical experiment based on optimized design strategies and artificial intelligence algorithms and found that weight and body mass index (BMI) had a profound effect on drug clearance and volume of distribution, and followed nonlinear fractal geometry-based relationships...
November 21, 2016: CPT: Pharmacometrics & Systems Pharmacology
Tanveer Ul Islam, Prasanna S Gandhi
Nature, in quest for the best designs has shaped its vital systems into fractal geometries. Effectual way of spontaneous fabrication of scalable, ordered fractal-like structures by controlling Saffman-Taylor instability in a lifted Hele-Shaw cell is deployed here. In lifted Hele-Shaw cell uncontrolled penetration of low-viscosity fluid into its high-viscosity counterpart is known to develop irregular, non-repeatable, normally short-lived, branched patterns. We propose and characterize experimentally anisotropies in a form of spatially distributed pits on the cell plates to control initiation and further penetration of non-splitting fingers...
November 16, 2016: Scientific Reports
Hongwei Yang, Béatrice A Baudet, Ting Yao
The surface roughness of soil grains affects the mechanical behaviour of soils, but the characterization of real soil grain roughness is still limited in both quantity and quality. A new method is proposed, which applies the power spectral density (PSD), typically used in tribology, to optical interferometry measurements of soil grain surfaces. The method was adapted to characterize the roughness of soil grains separately from their shape, allowing the scale of the roughness to be determined in the form of a wavevector range...
October 2016: Proceedings. Mathematical, Physical, and Engineering Sciences
Hao Hu, Robert M Ziff, Youjin Deng
The no-enclave percolation (NEP) model introduced recently by Sheinman et al. can be mapped to a problem of holes within a standard percolation backbone, and numerical measurements of such holes give the same size-distribution exponent τ=1.82(1) as found for the NEP model. An argument is given that τ=1+d_{B}/2≈1.822 for backbone holes, where d_{B} is the backbone dimension. On the other hand, a model of simple holes within a percolation cluster yields τ=1+d_{f}/2=187/96≈1.948, where d_{f} is the fractal dimension of the cluster, and this value is consistent with the experimental results of gel collapse of Sheinman et al...
October 28, 2016: Physical Review Letters
Otilia Constantina Rogoveanu, Diana Kamal, Magdalena Rodica Trăistaru, Costin Teodor Streba
Gonarthrosis is a degenerative disease that affects mainly older people, but whose incidence has increased significantly in the last decade in population under the age of 65. The main objective of this study was developing a predictive model of synovial membrane degradation in relation to local nerve structures in patients with knee osteoarthritis, based on advanced morphometry and artificial neural networks (ANNs). We present here a pilot test of the method, describing preliminary findings in analyzing a pre-set number of images...
2016: Romanian Journal of Morphology and Embryology, Revue Roumaine de Morphologie et Embryologie
Jun Cheng, Qing Ye, Zongbo Yang, Weijuan Yang, Junhu Zhou, Kefa Cen
The response mechanisms of microalgal mutant Chlorella PY-ZU1 cells were investigated in their removal of antibiotic tilmicosin from wastewater under 15% CO2. Low concentrations (0.01-2mgL(-1)) of tilmicosin in wastewater stimulated the growth of microalgal cells, whereas high concentrations (5-50mgL(-1)) of tilmicosin significantly inhibited cell growth. When initial tilmicosin concentration increased from 0 to 50mgL(-1), fractal dimension of microalgal cells monotonically increased from 1.36 to 1.62 and cell size monotonically decreased from 4...
November 3, 2016: Journal of Hazardous Materials
Michael Taylor, Irep Gözen, Samir Patel, Aldo Jesorka, Katia Bertoldi
We simulate the formation of spontaneous ruptures in supported phospholipid double bilayer membranes, using peridynamic modeling. Experiments performed on spreading double bilayers typically show two distinct kinds of ruptures, floral and fractal, which form spontaneously in the distal (upper) bilayer at late stages of double bilayer formation on high energy substrates. It is, however, currently unresolved which factors govern the occurrence of either rupture type. Variations in the distance between the two bilayers, and the occurrence of interconnections ("pinning sites") are suspected of contributing to the process...
2016: PloS One
Meiyan Xing, Cenran Li, Jinzhou Jiang, Yin Wang, Jian Yang
To improve excess sludge dewaterability, a two-stage vermifilter was developed to qualitatively and quantitatively analyze sludge physico-chemical properties (fractal dimension, zeta potential, extracellular polymeric substances (EPS), particle size distribution, etc.) and to correlate them with sludge dewatering characteristics (specific resistance to filtration (SRF) and capillary suction time (CST)). Results demonstrated that sludge dewatering performance was significantly improved after the primary vermifilter VF1 and the second-stage vermifilter VF2...
November 8, 2016: Applied Microbiology and Biotechnology
Tolga F Tözüm, Erhan Dursun, Serdar Uysal
BACKGROUND: The aim of the present study was to investigate whether the mandibular cortical index (MCI) has a relationship with fractal dimension of bone and/or implant stability, and to justify the possible association between MCI, fractal dimension, and stability. MATERIALS AND METHODS: Eighty-two subjects who received dental implants to replace missing mandibular premolar/molar sites were selected. Three months after surgical placement, implants were restored with fixed ceramic fused metal crowns...
December 2016: Implant Dentistry
Igor Pantic, Dejan Nesic, Milos Basailovic, Mila Cetkovic, Sanja Mazic, Jelena Suzic-Lazic, Martin Popevic
Despite previous research efforts in the fields of histology and cell physiology, the relationship between chromatin structural organization and nuclear shape remains unclear. The aim of this research was to test the existence and strength of correlations between mathematical parameters of chromatin microarchitecture and roundness of the nuclear envelope. On a sample of 240 nuclei of adrenal zona fasciculata cells stained using the DNA-specific Feulgen method, we quantified fractal parameters such as fractal dimension and lacunarity, as well as textural parameters such as angular second moment (ASM), entropy, inverse difference moment, contrast, and variance...
November 8, 2016: Microscopy and Microanalysis
Rajesh S Kumar, Neha Anegondi, Rachana S Chandapura, Suria Sudhakaran, Sujatha V Kadambi, Harsha L Rao, Tin Aung, Abhijit Sinha Roy
Purpose: To determine the discriminant function of optical coherence tomography angiography (OCTA) by disease severity in glaucoma. Methods: In this prospective, observational cross-sectional study, all subjects underwent visual fields, retinal nerve fiber layer (RNFL) measurements, and OCTA imaging. Local fractal analysis was applied to OCTA images (radial peripapillary capillaries [RPC] layer). Vessel density en face and inside the disc and spacing between large and small vessels were quantified...
November 1, 2016: Investigative Ophthalmology & Visual Science
Ye Yang, Jianhua Wang, Hong Jiang, Xiaoling Yang, Limiao Feng, Liang Hu, Liang Wang, Fan Lu, Meixiao Shen
Purpose: To investigate the retinal vascular network alterations in highly myopic eyes. Methods: Thirty-three highly myopic eyes from 21 subjects and 47 mildly myopic or emmetropic eyes from 24 healthy control subjects were enrolled. Optical coherence tomography angiography (OCTA) was used to image the superficial, deep, and whole retinal vascular plexuses at the macular region. Highly myopic eye images were analyzed after adjusting the ocular magnification using Bennett's formula...
November 1, 2016: Investigative Ophthalmology & Visual Science
Sun Young Cho, Abdul Aziz Shahid, Waqas Nazeer, Shin Min Kang
In this note, we give fixed point results in fractal generation (Julia sets and Mandelbrot sets) by using Noor iteration scheme with s-convexity. Researchers have already presented fixed point results in Mann and Ishikawa orbits that are examples of one-step and two-step feedback processes respectively. In this paper we present fixed point results in Noor orbit, which is a three-step iterative procedure.
2016: SpringerPlus
Min Li, Ye Yang, Hong Jiang, Giovanni Gregori, Luiz Roisman, Fang Zheng, Bilian Ke, Dongyi Qu, Jianhua Wang
PURPOSE: To investigate the changes of the retinal microvascular network and microcirculation in high myopia. DESIGN: A cross-sectional, matched, comparative clinical study. PARTICIPANTS: Twenty eyes of twenty subjects with non-pathological high myopia (28 ± 5 Years) with a refractive error of -6.31 ± 1.23 Diopters (mean ± standard deviation) and twenty eyes of twenty age- and gender-matched control subjects (30 ± 6 years) with a refractive error of -1...
November 3, 2016: American Journal of Ophthalmology
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