keyword
MENU ▼
Read by QxMD icon Read
search

fractals

keyword
https://www.readbyqxmd.com/read/28229127/the-application-of-retinal-fundus-camera-imaging-in-dementia-a-systematic-review
#1
REVIEW
Sarah McGrory, James R Cameron, Enrico Pellegrini, Claire Warren, Fergus N Doubal, Ian J Deary, Baljean Dhillon, Joanna M Wardlaw, Emanuele Trucco, Thomas J MacGillivray
INTRODUCTION: The ease of imaging the retinal vasculature, and the evolving evidence suggesting this microvascular bed might reflect the cerebral microvasculature, presents an opportunity to investigate cerebrovascular disease and the contribution of microvascular disease to dementia with fundus camera imaging. METHODS: A systematic review and meta-analysis was carried out to assess the measurement of retinal properties in dementia using fundus imaging. RESULTS: Ten studies assessing retinal properties in dementia were included...
2017: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring
https://www.readbyqxmd.com/read/28228513/shape-matters-animal-colour-patterns-as-signals-of-individual-quality
#2
REVIEW
Lorenzo Pérez-Rodríguez, Roger Jovani, Martin Stevens
Colour patterns (e.g. irregular, spotted or barred forms) are widespread in the animal kingdom, yet their potential role as signals of quality has been mostly neglected. However, a review of the published literature reveals that pattern itself (irrespective of its size or colour intensity) is a promising signal of individual quality across species of many different taxa. We propose at least four main pathways whereby patterns may reliably reflect individual quality: (i) as conventional signals of status, (ii) as indices of developmental homeostasis, (iii) by amplifying cues of somatic integrity and (iv) by amplifying individual investment in maintenance activities...
February 22, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28228335/alterations-in-cardiac-autonomic-control-in-spinal-cord-injury
#3
Fin Biering-Sørensen, Tor Biering-Sørensen, Nan Liu, Lasse Malmqvist, Jill Maria Wecht, Andrei Krassioukov
A spinal cord injury (SCI) interferes with the autonomic nervous system (ANS). The effect on the cardiovascular system will depend on the extent of damage to the spinal/central component of ANS. The cardiac changes are caused by loss of supraspinal sympathetic control and relatively increased parasympathetic cardiac control. Decreases in sympathetic activity result in heart rate and the arterial blood pressure changes, and may cause arrhythmias, in particular bradycardia, with the risk of cardiac arrest in those with cervical or high thoracic injuries...
February 15, 2017: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/28228016/island-nucleation-and-growth-with-anomalous-diffusion-in-one-dimension
#4
Ehsan H Sabbar, Jacques G Amar
Recently a general rate-equation (RE) theory of submonolayer island nucleation and growth was developed [J. G. Amar and M. Semaan, Phys. Rev. E 93, 062805 (2016)] which takes into account the critical island-size i, island fractal dimension df, substrate dimension d, and diffusion exponent μ, and good agreement with simulations was found for the case of irreversible growth corresponding to a critical island-size i=1 with d = 2. Here we present the results of simulations carried out in 1D (corresponding to d = 1) of island nucleation and growth with anomalous diffusion which were carried out for both the case of superdiffusion (μ>1) and subdiffusion (μ<1)...
February 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28227977/surrogate-analysis-of-fractal-dimensions-from-semg-sensor-array-as-a-predictor-of-chronic-low-back-pain
#5
Manouane Caza-Szoka, Daniel Massicotte, Francois Nougarou, Martin Descarreaux, Manouane Caza-Szoka, Daniel Massicotte, Francois Nougarou, Martin Descarreaux, Manouane Caza-Szoka, Daniel Massicotte, Martin Descarreaux, Francois Nougarou
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
https://www.readbyqxmd.com/read/28227935/heart-sound-segmentation-using-fractal-decomposition
#6
Rijil Thomas, Ling Lieng Hsi, Soh Cheong Boon, Erry Gunawan, Rijil Thomas, Ling Lieng Hsi, Soh Cheong Boon, Erry Gunawan
In order to assist cardiac diagnosis by phonocardiography, the automated identification of fundamental heart sounds for heart beat segmentation in a cardiac cycle plays a significant role in signal processing. Recent advancements in signal processing have also shown the potential of multifractality in biomedical applications. Hence, in this paper, the multifractal property of heart sounds is utilized to identify first and second heart sounds. The root mean square (rms) fluctuation used to obtain multifractal/singularity spectrum is used to decompose the heart sound into its own fractally-important components in time domain along with simultaneous Gaussianity test to filter out fundamental components...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227872/detection-of-different-types-of-noise-in-lung-sounds
#7
A Leal, R Couceiro, I Chouvarda, N Maglaveras, J Henriques, R Paiva, P Carvalho, C Teixeira, A Leal, R Couceiro, I Chouvarda, N Maglaveras, J Henriques, R Paiva, P Carvalho, C Teixeira, R Couceiro, P Carvalho, C Teixeira, A Leal, R Paiva, J Henriques, N Maglaveras, I Chouvarda
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
https://www.readbyqxmd.com/read/28227773/whole-heart-modeling-spatiotemporal-dynamics-of-electrical-wave-conduction-and-propagation
#8
Hui Yang, Yun Chen, Fabio M Leonelli, Hui Yang, Yun Chen, Fabio M Leonelli, Hui Yang, Fabio M Leonelli, Yun Chen
Cardiac electrical activities are varying in both space and time. Human heart consists of a fractal network of muscle cells, Purkinje fibers, arteries and veins. Whole-heart modeling of electrical wave conduction and propagation involves a greater level of complexity. Our previous work developed a computer model of the anatomically realistic heart and simulated the electrical conduction with the use of cellular automata. However, simplistic assumptions and rules limit its ability to provide an accurate approximation of real-world dynamics on the complex heart surface, due to sensitive dependence of nonlinear dynamical systems on initial conditions...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227475/label-free-detection-of-sex-determining-region-y-sry-via-capacitive-biosensor
#9
Shilpa Sivashankar, Christos Sapsanis, Sumeyra Agambayev, Ulrich Buttner, Khaled Nabil Salama, Shilpa Sivashankar, Christos Sapsanis, Sumeyra Agambayev, Ulrich Buttner, Khaled Nabil Salama, Khaled Nabil Salama, Shilpa Sivashankar, Sumeyra Agambayev, Christos Sapsanis, Ulrich Buttner
In this work, we present for the first time, the use of a simple fractal capacitive biosensor for the quantification and detection of sex-determining region Y (SRY) genes. This section of genetic code, which is found on the Y chromosome, finds importance for study as it causes fetuses to develop characteristics of male sex-like gonads when a mutation occurs. It is also an important genetic code in men, and disorders involving the SRY gene can cause infertility and sexual malfunction that lead to a variety of gene mutational disorders...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227382/a-new-approach-for-the-detection-of-architectural-distortions-using-textural-analysis-of-surrounding-tissue
#10
Imad Zyout, Roberto Togneri, Imad Zyout, Roberto Togneri, Roberto Togneri, Imad Zyout
Aiming at improving the performance of computer-aided detection of architectural distortion (AD) in mammograms, this paper investigates whether textural patterns of AD surrounding tissue (ST) have the potential to detect AD signatures. More specifically, for characterizing the presence of AD; we investigated the application of textural analysis for discriminating between AD surrounding tissue and normal breast parenchyma. We evaluated the underlying hypothesis using a dataset of 2544 regions of interest (ROI) obtained from the Digital Database for Screening Mammography (DDSM)...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227330/changes-in-inhaler-inhalation-acoustic-features-during-induced-bronchoconstriction-a-pilot-study
#11
Thomas A McCartan, Terence E Taylor, Imran Sulaiman, Richard W Costello, Richard B Reilly, Thomas A McCartan, Terence E Taylor, Imran Sulaiman, Richard W Costello, Richard B Reilly, Richard B Reilly, Thomas A McCartan, Terence E Taylor, Imran Sulaiman, Richard W Costello
Asthma is a chronic respiratory disease affecting millions of people worldwide, and is consequently a major issue for global health. Exacerbations are acute events involving the worsening of asthma's primary respiratory symptoms and are a major cause of morbidity in asthma patients, largely due to the unpredictability of their onset. This study aimed to investigate the relationship between changes in acoustic features of inhaler inhalations and changes in forced expiratory volume in one second (FEV1) that occur during a simulated exacerbation, a bronchial challenge test (BCT)...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227297/features-of-cerebral-oxygenation-detects-brain-injury-in-premature-infants
#12
John M O'Toole, Mmoloki Kenosi, Daragh Finn, Geraldine B Boylan, Eugene M Dempsey, John M O'Toole, Mmoloki Kenosi, Daragh Finn, Geraldine B Boylan, Eugene M Dempsey, Daragh Finn, Eugene M Dempsey, Mmoloki Kenosi, John M Otoole, Geraldine B Boylan
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
https://www.readbyqxmd.com/read/28227192/acoustic-evaluation-of-pirfenidone-on-patients-with-combined-pulmonary-fibrosis-emphysema-syndrome
#13
Sonia Charleston-Villalobos, Norma Castaneda-Villa, Ramon Gonzalez-Camarena, M Mejia-Avila, H Mateos-Toledo, Tomas Aljama-Corrales, Sonia Charleston-Villalobos, Norma Castaneda-Villa, Ramon Gonzalez-Camarena, M Mejia-Avila, H Mateos-Toledo, Tomas Aljama-Corrales, Tomas Aljama-Corrales, Ramon Gonzalez-Camarena, Sonia Charleston-Villalobos, Norma Castaneda-Villa, M Mejia-Avila, H Mateos-Toledo
The combined pulmonary fibrosis emphysema syndrome (CPFES) overall has a poor prognosis with a 5-year survival of 35-80%. Consequently, to evaluate possible positive effects on patients of novel agents as pirfenidone is relevant. However, the efficacy of pirfenidone in CPFES patients is still not well-known. In this study we propose an alternative to evaluate the effects of pirfenidone treatment on CPFES patients via acoustic information. Quantitative analysis of discontinuous adventitious lung sounds (DLS), known as crackles, has been promising to detect and characterize diverse pulmonary pathologies...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226862/novel-fractal-planar-electrode-design-for-efficient-neural-stimulation
#14
Xuefeng Wei, Mehdi Benmassaoud, Miriam Meller, Sindhuja Kuchibhatla, Xuefeng Wei, Mehdi Benmassaoud, Miriam Meller, Sindhuja Kuchibhatla, Mehdi Benmassaoud, Sindhuja Kuchibhatla, Miriam Meller, Xuefeng Wei
Planar electrodes are used in epidural spinal cord stimulation and cortical stimulation. Stimulation efficiency of an electrode is characterized by its ability to activate a volume of neural tissue with lower voltage and power requirements. As current density tends to increase towards the sharp edges of an electrode, we hypothesize that electrode designs involving a greater amount of sharp edges will have higher variations of current density, and therefore increase stimulation efficiency, compared to electrodes with flat or rounded edges...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226743/adaptive-higuchi-s-dimension-based-retinal-vessel-diameter-measurement
#15
Behzad Aliahmad, Dinesh K Kumar, Behzad Aliahmad, Dinesh K Kumar, Behzad Aliahmad, Dinesh K Kumar
This paper proposes the use of an adaptive model to measure the width of retinal vessels in fundus photographs. It is based on the hypothesis that the Higuchi's dimension of the cross-section is proportional to the vessel diameter. This approach does not require image segmentation and binarization of the vessels and therefore is suitable for machine based measurements. The model is developed using a synthetic image of the vessel of known diameter and added noise. As a first step, the vessel cross-section profiles were manually obtained and analyzed using Higuchi's fractal dimension method...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28219805/fusion-of-spatial-gray-level-dependency-and-fractal-texture-features-for-the-characterization-of-thyroid-lesions
#16
U Raghavendra, U Rajendra Acharya, Anjan Gudigar, Jen Hong Tan, Hamido Fujita, Yuki Hagiwara, Filippo Molinari, Pailin Kongmebhol, Kwan Hoong Ng
Thyroid is a small gland situated at the anterior side of the neck and one of the largest glands of the endocrine system. The abrupt cell growth or malignancy in the thyroid gland may cause thyroid cancer. Ultrasound images distinctly represent benign and malignant lesions, but accuracy may be poor due to subjective interpretation. Computer Aided Diagnosis (CAD) can minimize the errors created due to subjective interpretation and assists to make fast accurate diagnosis. In this work, fusion of Spatial Gray Level Dependence Features (SGLDF) and fractal textures are used to decipher the intrinsic structure of benign and malignant thyroid lesions...
February 6, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28214682/fractal-theory-modeling-for-interpreting-nuclear-and-electrical-well-logging-data-and-establishing-lithological-cross-section-in-basaltic-environment-case-study-from-southern-syria
#17
Jamal Asfahani
Fractal theory modeling technique is newly proposed in this research for interpreting the combination of nuclear well logging, including natural gamma ray, density and neutron-porosity, and the electrical well logging of long and short normal, for establishing the lithological cross section in basaltic environments. The logging data of Kodana well, localized in Southern Syria are used for testing and applying the proposed technique. The established cross section clearly shows the distribution and the identification of four kinds of basalt which are hard massive basalt, hard basalt, pyroclastic basalt and the alteration basalt products, clay...
February 14, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28211794/test-retest-reliability-of-muscle-fiber-conduction-velocity-and-fractal-dimension-of-surface-emg-during-isometric-contractions
#18
Matteo Beretta-Piccoli, Giuseppe D'Antona, Cristian Zampella, Marco Barbero, Ron Clijsen, Corrado Cescon
The aim of this study was to determine the test-retest reliability of muscle fiber conduction velocity (CV) and fractal dimension (FD) obtained from multichannel surface electromyographic (sEMG) recordings. Forty healthy recreationally active subjects (20 men and 20 women) performed two elbow flexions on two trials with a 1-week interval. The first was a 20% maximal voluntary contraction (MVC) of 120 s, and the second at 60% MVC held until exhaustion. sEMG signals were detected from the biceps brachii, using bi-dimensional arrays...
February 17, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28209059/phase-behavior-of-aqueous-suspension-of-laponite-new-insights-with-microscopic-evidence
#19
Shweta Jatav, Yogesh M Joshi
Investigating microstructure of suspensions with particles having anisotropic shape that share complex interactions is a challenging task leading to competing claims. This work investigates phase behavior of one such system: aqueous Laponite suspension, which is highly contested in the literature, using rheological and microscopic tools. Remarkably, we observe that over a broad range of Laponite (1.4 to 4 weight %) and salt concentrations (0 to 7 mM), the system overwhelmingly demonstrates all the rheological characteristics of the sol-gel transition leading to a percolated network...
February 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28208504/structure-diffusion-relationship-of-polymer-membranes-with-different-texture
#20
Monika Krasowska, Anna Strzelewicz, Gabriela Dudek, Michał Cieśla
Two-dimensional diffusion in heterogenic composite membranes, i.e., materials comprising polymer with dispersed inorganic fillers, composed of ethylcellulose and magnetic powder is studied. In the experimental part, the morphology of membranes is described by the following characteristics: the amount of polymer matrix, the fractal dimension of polymer matrix, the average size of polymer matrix domains, the average number of obstacles in the proximity of each polymer matrix pixel. The simulation work concentrates on the motion of a particle in the membrane environment...
January 2017: Physical Review. E
keyword
keyword
53574
1
2
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"