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https://www.readbyqxmd.com/read/28445607/fractal-characteristics-of-the-microvascular-network-a-useful-index-to-assess-vascularization-level-of-porous-silk-fibroin-biomaterial
#1
Kuihua Zhan, Lun Bai, Qinqin Wu, Derong Lei, Guangqian Wang
The neovascularization of biomaterials for tissue engineering is not only related to growth of capillaries but also involves appropriate hierarchy distribution of the microvessels. In this study, we proposed hierarchy distribution contrast method which can assess vascular transport capacity, in order to examine the hierarchy distribution of the neovessels during vascularization of the porous silk fibroin biomaterials implanted into rats and its evolution. The results showed that the fractal characteristics appeared toward the end of the vascularization stages, and the structure of the microvascular network after 3 weeks of implantation was similar to the fractal microvascular tree with bifurcation exponent x=3 and fractal dimension D=1...
April 26, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28443878/influence-of-high-energy-electron-irradiation-on-the-network-structure-of-gelatin-hydrogels-as-investigated-by-small-angle-x-ray-scattering-saxs
#2
Emilia I Wisotzki, Paolo Tempesti, Emiliano Fratini, Stefan G Mayr
The impact of high energy crosslinking on the network structure of gelatin hydrogels was investigated in comparison to physically entangled gels by small-angle X-ray scattering (SAXS). Physically entangled gelatin of increasing concentration exhibited a nearly constant correlation length of several nanometers. These gels had scattering behavior close to that of polymer coils swollen in a good solvent, as evidenced by the Porod exponent of 1.8. The mass fractal dimension decreased towards 1, indicating increased formation of semiflexible gelatin triple helices and rod-like structures as a function of the gelatin concentration...
April 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28443694/fractal-features-and-surface-micromorphology-of-unworn-surfaces-of-rigid-gas-permeable-contact-lenses
#3
Ştefan Ţălu, Miroslaw Bramowicz, Slawomir Kulesza, Ilenia Fiorillo, Stefano Giovanzana
PURPOSE: The aim of this exploratory study was to investigate the micromorphology of surfaces of rigid gas permeable (RGP) contact lenses (CLs) using atomic force microscopy (AFM) followed by fractal analysis. MATERIALS AND METHODS: In order to characterize in a quantitative manner the micromorphology of surfaces of new and unworn RGP CLs made of twelve different materials, AFM was taken and then analyzed using fractal methods. Surface topography was sampled in an intermittent-contact mode in air, on square areas of 5 × 5 µm(2) (MultiMode with Nanoscope V (Bruker)...
April 26, 2017: Current Eye Research
https://www.readbyqxmd.com/read/28439649/differences-in-tibial-subchondral-bone-structure-evaluated-using-plain-radiographs-between-knees-with-and-without-cartilage-damage-or-bone-marrow-lesions-the-oulu-knee-osteoarthritis-study
#4
Jukka Hirvasniemi, Jérôme Thevenot, Ali Guermazi, Jana Podlipská, Frank W Roemer, Miika T Nieminen, Simo Saarakkala
OBJECTIVES: To investigate whether subchondral bone structure from plain radiographs is different between subjects with and without articular cartilage damage or bone marrow lesions (BMLs). METHODS: Radiography-based bone structure was assessed from 80 subjects with different stages of knee osteoarthritis using entropy of Laplacian-based image (ELap) and local binary patterns (ELBP), homogeneity index of local angles (HIAngles,mean), and horizontal (FDHor) and vertical fractal dimensions (FDVer)...
April 24, 2017: European Radiology
https://www.readbyqxmd.com/read/28439074/how-to-test-for-partially-predictable-chaos
#5
Hendrik Wernecke, Bulcsú Sándor, Claudius Gros
For a chaotic system pairs of initially close-by trajectories become eventually fully uncorrelated on the attracting set. This process of decorrelation can split into an initial exponential decrease and a subsequent diffusive process on the chaotic attractor causing the final loss of predictability. Both processes can be either of the same or of very different time scales. In the latter case the two trajectories linger within a finite but small distance (with respect to the overall extent of the attractor) for exceedingly long times and remain partially predictable...
April 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28437483/quantitative-microvascular-analysis-of-retinal-venous-occlusions-by-spectral-domain-optical-coherence-tomography-angiography
#6
Nicole Koulisis, Alice Y Kim, Zhongdi Chu, Anoush Shahidzadeh, Bruce Burkemper, Lisa C Olmos de Koo, Andrew A Moshfeghi, Hossein Ameri, Carmen A Puliafito, Veronica L Isozaki, Ruikang K Wang, Amir H Kashani
PURPOSE: To quantitatively evaluate the retinal microvasculature in human subjects with retinal venous occlusions (RVO) using optical coherence tomography angiography (OCTA). DESIGN: Retrospective, cross-sectional, observational case series. PARTICIPANTS: Sixty subjects (84 eyes) were included (20 BRVO, 14 CRVO, 24 unaffected fellow eyes, and 26 controls). METHODS: OCTA was performed on a prototype, spectral domain-OCTA system in the 3x3mm central macular region...
2017: PloS One
https://www.readbyqxmd.com/read/28436450/definition-of-fractal-topography-to-essential-understanding-of-scale-invariance
#7
Yi Jin, Ying Wu, Hui Li, Mengyu Zhao, Jienan Pan
Fractal behavior is scale-invariant and widely characterized by fractal dimension. However, the cor-respondence between them is that fractal behavior uniquely determines a fractal dimension while a fractal dimension can be related to many possible fractal behaviors. Therefore, fractal behavior is independent of the fractal generator and its geometries, spatial pattern, and statistical properties in addition to scale. To mathematically describe fractal behavior, we propose a novel concept of fractal topography defined by two scale-invariant parameters, scaling lacunarity (P) and scaling coverage (F)...
April 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28430738/three-dimensional-fractal-analysis-of-99mtc-maa-spect-images-in-chronic-thromboembolic-pulmonary-hypertension-for-evaluation-of-response-to-balloon-pulmonary-angioplasty-association-with-pulmonary-arterial-pressure
#8
Yasuhiro Maruoka, Michinobu Nagao, Shingo Baba, Takuro Isoda, Yoshiyuki Kitamura, Yuzo Yamazaki, Koichiro Abe, Masayuki Sasaki, Kohtaro Abe, Hiroshi Honda
OBJECTIVE: Balloon pulmonary angioplasty (BPA) is used for inoperable chronic thromboembolic pulmonary hypertension (CTEPH), but its effect cannot be evaluated noninvasively. We devised a noninvasive quantitative index of response to BPA using three-dimensional fractal analysis (3D-FA) of technetium-99m-macroaggregated albumin (Tc-MAA) single-photon emission computed tomography (SPECT). PATIENTS AND METHODS: Forty CTEPH patients who underwent pulmonary perfusion scintigraphy and mean pulmonary arterial pressure (mPAP) measurement by right heart catheterization before and after BPA were studied...
April 20, 2017: Nuclear Medicine Communications
https://www.readbyqxmd.com/read/28430461/quantifying-the-dynamical-complexity-of-chaotic-time-series
#9
Antonio Politi
A powerful approach is proposed for the characterization of chaotic signals. It is based on the combined use of two classes of indicators: (i) the probability of suitable symbolic sequences (obtained from the ordinal patterns of the corresponding time series); (ii) the width of the corresponding cylinder sets. This way, much information can be extracted and used to quantify the complexity of a given signal. As an example of the potentiality of the method, I introduce a modified permutation entropy which allows for quantitative estimates of the Kolmogorov-Sinai entropy in hyperchaotic models, where other methods would be unpractical...
April 7, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28430459/direct-observation-of-percolation-in-the-yielding-transition-of-colloidal-glasses
#10
Antina Ghosh, Zoe Budrikis, Vijayakumar Chikkadi, Alessandro L Sellerio, Stefano Zapperi, Peter Schall
When strained beyond the linear regime, soft colloidal glasses yield to steady-state plastic flow in a way that is similar to the deformation of conventional amorphous solids. Because of the much larger size of the colloidal particles with respect to the atoms comprising an amorphous solid, colloidal glasses allow us to obtain microscopic insight into the nature of the yielding transition, as we illustrate here combining experiments, atomistic simulations, and mesoscopic modeling. Our results unanimously show growing clusters of nonaffine deformation percolating at yielding...
April 7, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28429332/the-effect-of-post-injection-18-f-fdg-pet-scanning-time-on-texture-analysis-of-peripheral-nerve-sheath-tumours-in-neurofibromatosis-1
#11
Eitan Lovat, Musib Siddique, Vicky Goh, Rosalie E Ferner, Gary J R Cook, Victoria S Warbey
BACKGROUND: Texture features are being increasingly evaluated in (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) as adjunctive imaging biomarkers in a number of different cancers. Whilst studies have reported repeatability between scans, there have been no studies that have specifically investigated the effect that the time of acquisition post-injection of (18)F-FDG has on texture features. The aim of this study was to investigate if texture features change between scans performed at different time points post-injection...
December 2017: EJNMMI Research
https://www.readbyqxmd.com/read/28422647/eeg-based-affect-and-workload-recognition-in-a-virtual-driving-environment-for-asd-intervention
#12
Jing Fan, Joshua W Wade, Alexandra P Key, Zachary Warren, Nilanjan Sarkar
OBJECTIVE: To build group-level classification models capable of recognizing affective states and mental workload of individuals with autism spectrum disorder (ASD) during driving skill training. METHODS: Twenty adolescents with ASD participated in a six-session virtual reality driving simulator based experiment, during which their electroencephalogram (EEG) data were recorded alongside driving events and a therapist's rating of their affective states and mental workload...
April 12, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28422299/incorporation-of-pre-therapy-18-f-fdg-uptake-data-with-ct-texture-features-into-a-radiomics-model-for-radiation-pneumonitis-diagnosis
#13
Gregory J Anthony, Alexandra Cunliffe, Richard Castillo, Ngoc Pham, Thomas Guerrero, Samuel G Armato, Hania Al-Hallaq
PURPOSE: To determine whether the addition of standardized uptake value (SUV) from PET scans to CT lung texture features could improve a radiomics-based model of radiation pneumonitis (RP) diagnosis in patients undergoing radiotherapy. METHODS AND MATERIALS: Anonymized data from 96 esophageal cancer patients (18 RP-positive cases of Grade ≥ 2) were collected including pre-therapy PET/CT scans, pre-/post-therapy diagnostic CT scans and RP status. Twenty texture features (first-order, fractal, Laws' filter and gray-level co-occurrence matrix) were calculated from diagnostic CT scans and compared in anatomically matched regions of the lung...
April 19, 2017: Medical Physics
https://www.readbyqxmd.com/read/28419951/can-fractal-methods-applied-to-video-tracking-detect-the-effects-of-deltamethrin-pesticide-or-mercury-on-the-locomotion-behavior-of-shrimps
#14
Bruno Mendes Tenorio, Eurípedes Alves da Silva Filho, Gentileza Santos Martins Neiva, Valdemiro Amaro da Silva, Fernanda das Chagas Angelo Mendes Tenorio, Themis de Jesus da Silva, Emerson Carlos Soares E Silva, Romildo de Albuquerque Nogueira
Shrimps can accumulate environmental toxicants and suffer behavioral changes. However, methods to quantitatively detect changes in the behavior of these shrimps are still needed. The present study aims to verify whether mathematical and fractal methods applied to video tracking can adequately describe changes in the locomotion behavior of shrimps exposed to low concentrations of toxic chemicals, such as 0.15µgL(-1) deltamethrin pesticide or 10µgL(-1) mercuric chloride. Results showed no change after 1min, 4, 24, and 48h of treatment...
April 15, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28418811/hypertrabeculated-left-ventricular-myocardium-in-relationship-to-myocardial-function-and-fibrosis-the-multi-ethnic-study-of-atherosclerosis
#15
Nadine Kawel-Boehm, Robyn L McClelland, Filip Zemrak, Gabriella Captur, W Gregory Hundley, Chia-Ying Liu, James C Moon, Steffen E Petersen, Bharath Ambale-Venkatesh, João A C Lima, David A Bluemke
Purpose To determine if excess greater left ventricle (LV) trabeculation is associated with decreased average regional myocardial function, diffuse fibrosis, or both. Materials and Methods This was a HIPAA-compliant institutional board approved multicenter study, and all participants provided written informed consent. Participants in the Multi-Ethnic Study of Atherosclerosis (MESA) underwent a comprehensive cardiac magnetic resonance (MR) examination. LV trabeculation was measured with the maximal apical fractal dimension (FD), which is a marker of endocardial complexity...
April 17, 2017: Radiology
https://www.readbyqxmd.com/read/28418438/a-scalable-self-priming-fractal-branching-microchannel-net-chip-for-digital-pcr
#16
Qiangyuan Zhu, Yanan Xu, Lin Qiu, Congcong Ma, Bingwen Yu, Qi Song, Wei Jin, Qinhan Jin, Jinyu Liu, Ying Mu
As an absolute quantification method at the single-molecule level, digital PCR has been widely used in many bioresearch fields, such as next generation sequencing, single cell analysis, gene editing detection and so on. However, existing digital PCR methods still have some disadvantages, including high cost, sample loss, and complicated operation. In this work, we develop an exquisite scalable self-priming fractal branching microchannel net digital PCR chip. This chip with a special design inspired by natural fractal-tree systems has an even distribution and 100% compartmentalization of the sample without any sample loss, which is not available in existing chip-based digital PCR methods...
April 18, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28417927/wireless-fractal-ultra-dense-cellular-networks
#17
Yixue Hao, Min Chen, Long Hu, Jeungeun Song, Mojca Volk, Iztok Humar
With the ever-growing number of mobile devices, there is an explosive expansion in mobile data services. This represents a challenge for the traditional cellular network architecture to cope with the massive wireless traffic generated by mobile media applications. To meet this challenge, research is currently focused on the introduction of a small cell base station (BS) due to its low transmit power consumption and flexibility of deployment. However, due to a complex deployment environment and low transmit power of small cell BSs, the coverage boundary of small cell BSs will not have a traditional regular shape...
April 12, 2017: Sensors
https://www.readbyqxmd.com/read/28416437/the-ct-based-fractal-analysis-of-trabecular-bone-structure-may-help-in-detecting-decreased-quality-of-bone-prior-to-urgent-spinal-procedures
#18
Marcin Czyz, Arion Kapinas, James Holton, Renata Pyzik, Bronek M Boszczyk, Nasir A Quraishi
BACKGROUND CONTEXT: To date no reliable method is available to determine the parameters of bone density based on the routine spinal CT in the emergency setup. We propose the use of fractal analysis to detect patients with poor quality of bone prior to urgent or semi-urgent spinal procedures. PURPOSE: To validate the hypothesis that the CT-based fractal analysis of the trabecular bone structure may help in detecting patients with poor quality of bone prior to urgent spinal procedures...
April 14, 2017: Spine Journal: Official Journal of the North American Spine Society
https://www.readbyqxmd.com/read/28415333/melting-of-a-nonequilibrium-vortex-crystal-in-a-fluid-film-with-polymers-elastic-versus-fluid-turbulence
#19
Anupam Gupta, Rahul Pandit
We perform a direct numerical simulation of the forced, incompressible two-dimensional Navier-Stokes equation coupled with the FENE-P equations for the polymer-conformation tensor. The forcing is such that, without polymers and at low Reynolds numbers Re, the film attains a steady state that is a square lattice of vortices and antivortices. We find that, as we increase the Weissenberg number Wi, a sequence of nonequilibrium phase transitions transforms this lattice, first to spatially distorted, but temporally steady, crystals and then to a sequence of crystals that oscillate in time, periodically, at low Wi, and quasiperiodically, for slightly larger Wi...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28415275/effects-of-surface-roughness-on-shear-viscosity
#20
Michail Papanikolaou, Michael Frank, Dimitris Drikakis
This paper investigates the effect of surface roughness on fluid viscosity using molecular dynamics simulations. The three-dimensional model consists of liquid argon flowing between two solid walls whose surface roughness was modeled using fractal theory. In tandem with previously published experimental work, our results show that, while the viscosity in smooth channels remains constant across the channel width, in the presence of surface roughness it increases close to the walls. The increase of the boundary viscosity is further accentuated by an increase in the depth of surface roughness...
March 2017: Physical Review. E
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