Read by QxMD icon Read

fractal dimension

Khouloud Fekih Ahmed, Adel Aschi, Taco Nicolai
Hybrid protein-polysaccharide particles were formed by complexation of fractal whey protein aggregates and the cationic polysaccharide chitosan. The fractal aggregates were preformed by heating native whey protein isolate at pH 7 and subsequently mixed with chitosan at pH 3 where these proteins and polysaccharides don't interact with each other. Stable dispersions of protein-polysaccharide particles were formed spontaneously when the pH was gradually increased between 4.1 and 6.8, whereas in the absence of chitosan the fractal aggregates precipitated between pH 4...
May 15, 2018: Colloids and Surfaces. B, Biointerfaces
Dai Xue, Yancheng Wang, Jiaxin Zhang, Deqing Mei, Yue Wang, Shaochen Chen
To fully actualize artificial, cell-laden biological models in tissue engineering, such as 3D organoids and organs-on-a-chip systems, cells need to be patterned such that they can precisely mimic natural microenvironments in vitro. Despite increasing interest in this area, patterning cells at multiscales (~10 μm - 10 mm) remains a significant challenge in bioengineering. Here we report a projection-based 3D printing system that achieves rapid and high-resolution fabrication of hydrogel scaffolds featuring intricate channels for multi-scale cell patterning...
May 21, 2018: ACS Applied Materials & Interfaces
Kohei Aoki, Yotaro Izumi, Wataru Watanabe, Yuji Shimizu, Hisato Osada, Norinari Honda, Toshihide Itoh, Mitsuo Nakayama
BACKGROUND: While many studies have evaluated the change in lung volume before and after lung resection and correlated this with pulmonary function test results, there is very little evidence on the changes in ventilation perfusion ratio (V/Q) before versus after lung resection. In the present pilot study, we evaluated if V/Q mapping can be constructed using dual energy CT images. METHODS: Thirty-one lung cancer patients planned for pulmonary resection were included in this study...
May 18, 2018: Journal of Cardiothoracic Surgery
Wenlong Wang, M A Moore, Helmut G Katzgraber
The fractal dimension of domain walls produced by changing the boundary conditions from periodic to antiperiodic in one spatial direction is studied using both the strong-disorder renormalization group algorithm and the greedy algorithm for the Edwards-Anderson Ising spin-glass model for up to six space dimensions. We find that for five or fewer space dimensions, the fractal dimension is lower than the space dimension. This means that interfaces are not space filling, thus implying that replica symmetry breaking is absent in space dimensions fewer than six...
March 2018: Physical Review. E
Manish Sharma, Deepanshu Goyal, P V Achuth, U Rajendra Acharya
Sleep related disorder causes diminished quality of lives in human beings. Sleep scoring or sleep staging is the process of classifying various sleep stages which helps to detect the quality of sleep. The identification of sleep-stages using electroencephalogram (EEG) signals is an arduous task. Just by looking at an EEG signal, one cannot determine the sleep stages precisely. Sleep specialists may make errors in identifying sleep stages by visual inspection. To mitigate the erroneous identification and to reduce the burden on doctors, a computer-aided EEG based system can be deployed in the hospitals, which can help identify the sleep stages, correctly...
May 10, 2018: Computers in Biology and Medicine
Cong Chen, Zhi-Cheng He, Yu Shi, Wenchao Zhou, Xia Zhang, Hua-Liang Xiao, Hai-Bo Wu, Xiao-Hong Yao, Wan-Chun Luo, You-Hong Cui, Shideng Bao, Hsiang-Fu Kung, Xiu-Wu Bian, Yi-Fang Ping
The microvascular profile has been included in the WHO glioma grading criteria. Nevertheless, microvessels in gliomas of the same WHO grade, e.g., WHO IV glioblastoma (GBM), exhibit heterogeneous and polymorphic morphology, whose possible clinical significance remains to be determined. In this study, we employed a fractal geometry-derived parameter, microvascular fractal dimension (mvFD), to quantify microvessel complexity and developed a home-made macro in Image J software to automatically determine mvFD from the microvessel-stained immunohistochemical images of GBM...
May 15, 2018: Laboratory Investigation; a Journal of Technical Methods and Pathology
Zhenbei Wang, Jun Nan, Xiaoyu Ji, Yueming Yang
Dynamic analysis on the variation of particle size distribution (PSD) and the fractal characteristics of PSD (Df ) were investigated to better understand the continuous procedure of the floc growth and optimize the control of flocculation process. It was found that the flocculation process could be divided into three stages, i.e., the micro-flocculation stage, the growth stage and the steady (or breakage) stage. As the stage which is crucial to the morphology of micro-flocs (the building blocks of large flocs), the micro-flocculation stage plays an important role on flocculation/sedimentation process...
August 15, 2018: Science of the Total Environment
J Cheraghalizadeh, M N Najafi, H Mohammadzadeh, A Saber
The self-avoiding walk on the square site-diluted correlated percolation lattice is considered. The Ising model is employed to realize the spatial correlations of the metric space. As a well-accepted result, the (generalized) Flory's mean-field relation is tested to measure the effect of correlation. After exploring a perturbative Fokker-Planck-like equation, we apply an enriched Rosenbluth Monte Carlo method to study the problem. To be more precise, the winding angle analysis is also performed from which the diffusivity parameter of Schramm-Loewner evolution theory (κ) is extracted...
April 2018: Physical Review. E
Jianrui Feng, Pengwan Chen, Mo Li
Atomic packing is still a mystery for the topologically disordered amorphous solids owing primarily to the absence of Bragg diffraction in this class of materials. Among many hypotheses, a fractal packing is suggested based on a scaling relation with "2.5 power law" in multicomponent metallic glasses. Here we examine the atomic packing critically in a pure Tantalum metallic glass under hydrostatic pressure. Without any complications of chemical compositions as in the multicomponent systems, the genuine amorphous structure in the single component metallic glass exhibits cubic scaling exponent that indicates absence of the 2...
May 14, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Cesar I N Sampaio Filho, José S Andrade, Hans J Herrmann, André A Moreira
The elastic backbone is the set of all shortest paths. We found a new phase transition at p_{eb} above the classical percolation threshold at which the elastic backbone becomes dense. At this transition in 2D, its fractal dimension is 1.750±0.003, and one obtains a novel set of critical exponents β_{eb}=0.50±0.02, γ_{eb}=1.97±0.05, and ν_{eb}=2.00±0.02, fulfilling consistent critical scaling laws. Interestingly, however, the hyperscaling relation is violated. Using Binder's cumulant, we determine, with high precision, the critical probabilities p_{eb} for the triangular and tilted square lattice for site and bond percolation...
April 27, 2018: Physical Review Letters
Joe P Chen, Alexander Teplyaev, Konstantinos Tsougkas
We study the spectral zeta functions of the Laplacian on fractal sets which are locally self-similar fractafolds, in the sense of Strichartz. These functions are known to meromorphically extend to the entire complex plane, and the locations of their poles, sometimes referred to as complex dimensions, are of special interest. We give examples of locally self-similar sets such that their complex dimensions are not on the imaginary axis, which allows us to interpret their Laplacian determinant as the regularized product of their eigenvalues...
2018: Letters in Mathematical Physics
M A Idiazabal-Alecha, M V Sebastian-Guerrero, M A Navascues-Sanagustin, C Arcos-Sanchez, M V Arana-Aritmendiz, C Ruiz-Lopez, J M Iso-Perez
INTRODUCTION: Attention is one of the most widely studied superior cerebral functions and base of many other cognitive processes. It is sometimes understood as concentration on a task or target. The level of execution of a task and the ability to process information are dependent on the state of cerebral activation of the subject. This brain activity can be recorded with the electroencephalogram (EEG). AIM: Attention is studied in states of rest and during the performance of tasks in military personnel, exploring the differences between two groups (cadets and officers/NCOs)...
May 16, 2018: Revista de Neurologia
Emmanuel Luján, Daniela Soto, María S Rosito, Alejandro Soba, Liliana N Guerra, Juan C Calvo, Guillermo Marshall, Cecilia Suárez
Mathematical modelling approaches have become increasingly abundant in cancer research. Tumour infiltration extent and its spatial organization depend both on the tumour type and stage and on the bio-physicochemical characteristics of the microenvironment. This sets a complex scenario that often requires a multidisciplinary and individually adjusted approach. The ultimate goal of this work is to present an experimental/numerical combined method for the development of a three-dimensional mathematical model with the ability to reproduce the growth and infiltration patterns of a given avascular microtumour in response to different microenvironmental conditions...
May 9, 2018: Integrative Biology: Quantitative Biosciences From Nano to Macro
Matteo Beretta-Piccoli, Gennaro Boccia, Tessa Ponti, Ron Clijsen, Marco Barbero, Corrado Cescon
The relationship between fractal dimension of the surface electromyogram (sEMG) and the intensity of muscle contraction is still controversial in simulated and experimental conditions. To support the use of fractal analysis to investigate myoelectric fatigue, it is crucial to establish the interdependence between fractal dimension and muscle contraction intensity. We analyzed the behavior of fractal dimension, conduction velocity, mean frequency, and average rectified value in twenty-eight volunteers at nine levels of isometric force...
2018: BioMed Research International
Zeng-Nian Yuan, Hua Chen, Jing-Ming Li, Bin Dai, Wei-Bin Zhang
In order to study the fracture behavior and structure evolution of 1,3,5-Triamino-2,4,6-Trinitrobenzene (TATB)-based polymer bonded explosive in thermal-mechanical loading, in-situ studies were performed on X-ray computed tomography system using quasi-static Brazilian test. The experiment temperature was set from −20 °C to 70 °C. Three-dimensional morphology of cracks at different temperatures was obtained through digital image process. The various fracture modes were compared by scanning electron microscopy...
May 4, 2018: Materials
Moosarreza Shamsyeh Zahedi, Jochen Zeil
Recent work on virtual reality navigation in humans has suggested that navigational success is inversely correlated with the fractal dimension (FD) of artificial scenes. Here we investigate the generality of this claim by analysing the relationship between the fractal dimension of natural insect navigation environments and a quantitative measure of the navigational information content of natural scenes. We show that the fractal dimension of natural scenes is in general inversely proportional to the information they provide to navigating agents on heading direction as measured by the rotational image difference function (rotIDF)...
2018: PloS One
Manuel Röhrich, Kristin Huang, Daniel Schrimpf, Nathalie L Albert, Thomas Hielscher, Andreas von Deimling, Ulrich Schüller, Antonia Dimitrakopoulou-Strauss, Uwe Haberkorn
PURPOSE: Dynamic 18 F-FET PET/CT is a powerful tool for the diagnosis of gliomas.18 F-FET PET time-activity curves (TAC) allow differentiation between histological low-grade gliomas (LGG) and high-grade gliomas (HGG). Molecular methods such as epigenetic profiling are of rising importance for glioma grading and subclassification. Here, we analysed dynamic 18 F-FET PET data, and the histological and epigenetic features of 44 gliomas. METHODS: Dynamic 18 F-FET PET was performed in 44 patients with newly diagnosed, untreated glioma: 10 WHO grade II glioma, 13 WHO grade III glioma and 21 glioblastoma (GBM)...
May 7, 2018: European Journal of Nuclear Medicine and Molecular Imaging
Kun Li, Huanxiang Yang, Xu Han, Lingyu Xue, Yang Lv, Jinhua Li, Zhanyong Fu, Chuanrong Li, Weixing Shen, Huiling Guo, Yikun Zhang
To study the fractal dimensions of the soil particle size distributions (PSDs) within different plantations (of Pinus densiflora, Quercus acutissima, Robinia pseudoacacia, and Larix kaempferi) and evaluate PSDs as an indicator of the likelihood of Robinia pseudoacacia invasion, the soil porosity of 0-20 cm soil layers was measured at different plantations in the Yaoxiang Forest Farm, Shandong Province, China. The results showed that the fractal dimension (Dm ) values varied from 2.59 to 2.70 among the different plantations and were significantly negatively correlated to sand content and positively correlated to silt content and clay content...
May 4, 2018: Scientific Reports
L Y Xu, M Y Wang, X Z Shi, Q B Yu, Y J Shi, S X Xu, W X Sun
The shift from rice-wheat rotation (RWR) to greenhouse vegetable soils has been widely practiced in China. Several studies have discussed the changes in soil properties with land-use changes, but few studies have sought to address the differences in soil pore properties, especially for fields based on long-term organic fertilization under greenhouse vegetable system from RWR fields. This study uses the X-ray computed tomography (CT) scanning and statistical analysis to compare the long-term effects of the conversion of organic greenhouse vegetable fields (over one year, nine years, and fourteen years) from RWR fields on the soil macropore structure as well as the influencing factors from samples obtained in Nanjing, Jiangsu, China, using the surface soil layer and triplicate samples...
August 1, 2018: Science of the Total Environment
Sylwia Szerakowska, Barbara Woronko, Maria J Sulewska, Edward Oczeretko
Well-rounded grains extracted from aeolian and subaqueous environments were analysed to determine a quantitative parameter describing the microtopographic surface properties of sand-sized quartz grains, expressed as a degree of smoothness or as an inverse roughness. To this end, the spectral method was used to calculate their fractal dimension values. Fractal characteristics and spectral fractal dimension (DS ) were determined for a scanning electron microscope (SEM) image (560 × 560 pixels) obtained for each study grain...
April 23, 2018: Micron: the International Research and Review Journal for Microscopy
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"