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Di Bacco VE, Gage WH. Gait variability, fractal dynamics, and statistical regularity of treadmill and overground walking recorded with a smartphone. Gait Posture 2024; 111:53-58. [PMID: 38636334 DOI: 10.1016/j.gaitpost.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 03/20/2024] [Accepted: 04/04/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND The nonlinear variability present during steady-state gait may provide a signature of health and showcase one's walking adaptability. Although treadmills can capture vast amounts of walking data required for estimating variability within a small space, gait patterns may be misrepresented compared to an overground setting. Smartphones may provide a low-cost and user-friendly estimate of gait patterns among a variety of walking settings. However, no study has investigated differences in gait patterns derived from a smartphone between treadmill walking (TW) and overground walking (OW). RESEARCH QUESTION This study implemented a smartphone accelerometer to compare differences in temporal gait variability and gait dynamics between TW and OW. METHODS Sixteen healthy adults (8F; 24.7 ± 3.8 years) visited the laboratory on three separate days and completed three 8-minute OW and three TW trials, at their preferred speed, during each visit. The inter-stride interval was calculated as the time difference between right heel contact events located within the vertical accelerometery signals recorded from a smartphone while placed in participants front right pant pocket during walking trials. The inter-stride interval series was used to calculate stride time standard deviation (SD) and coefficient of variation (COV), statistical persistence (fractal scaling index), and statistical regularity (sample entropy). Two-way analysis of variance compared walking condition and laboratory visits for each measure. RESULTS Compared to TW, OW displayed significantly (p < 0.01) greater stride time SD (0.014 s, 0.020 s), COV (1.26 %, 1.82 %), fractal scaling index (0.70, 0.79) and sample entropy (1.43, 1.63). No differences were found between visits for all measures. SIGNIFICANCE Smartphone-based assessment of gait provides the ability to distinguish between OW and TW conditions, similar to previously established methodologies. Furthermore, smartphones may be a low-cost and user-friendly tool to estimate gait patterns outside the laboratory to improve ecological validity, with implications for free-living monitoring of gait among various populations.
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Affiliation(s)
- Vincenzo E Di Bacco
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada.
| | - William H Gage
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
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2
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Polo J, López H, Hernández C. Random number generator based on a memristive circuit. Heliyon 2024; 10:e26635. [PMID: 38404794 PMCID: PMC10884930 DOI: 10.1016/j.heliyon.2024.e26635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 02/11/2024] [Accepted: 02/16/2024] [Indexed: 02/27/2024] Open
Abstract
In this paper we discuss the details, limitations, and difficulties of the implementation in hardware of a memristor-based random number generator that exhibits monofractal/multifractal behavior. To do so, the components and selection criteria of a reference memristor and one proposed by the authors, the chaotic circuit leveraging them, and the processing that is performed on the chaotic signals to achieve the random discrete sequences are described. After applying the estimation tools, findings indicate that more than 60% of the proposed combinations allow generating random discrete sequences, with long-range dependence, and that both monofractal and multifractal behaviors can also be obtained. Consequently, a hardware system was achieved that can be used as a source of entropy in future synthetic biological signal generators.
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Affiliation(s)
- Juan Polo
- Faculty of Engineering, Universidad Distrital Francisco José de Caldas, Bogotá D.C., Colombia
| | - Hans López
- Faculty of Engineering, Universidad Distrital Francisco José de Caldas, Bogotá D.C., Colombia
| | - Cesar Hernández
- Technological Faculty, Universidad Distrital Francisco José de Caldas, Bogotá D.C., Colombia
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3
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Luo Y, Fan H, Lai X, Zeng Z, Lan X, Lin P, Tang L, Wang W, Chen Y, Tang Y. Flexible liquid metal-based microfluidic strain sensors with fractal-designed microchannels for monitoring human motion and physiological signals. Biosens Bioelectron 2024; 246:115905. [PMID: 38056340 DOI: 10.1016/j.bios.2023.115905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/28/2023] [Accepted: 11/29/2023] [Indexed: 12/08/2023]
Abstract
With the rapid advancement of wearable electronics, there is an increasing demand for high-performance flexible strain sensors. In this work, a flexible strain sensor based on liquid metal (LM)-integrated into a microfluidic device is developed with Peano-type fractal structure design. Compared with the microfluidic sensors with straight and wavy microchannels, the sensor with Peano-shaped channels shows lower hysteresis and improved stretchability. Furthermore, the increase of the fractal order can further improve the sensing performances. The third-order Peano sensor exhibits excellent mechanical and electrical properties, including high tensile capability (490.3%), minimal hysteresis (DH = 0.86%), ultra-low detection limit (0.1%), low overshoot, rapid response time (117 ms), as well as good stability and durability. By adding two independent and perpendicular straight channels to the Peano sensing unit, the feasibility of multi-directional strain recognition is demonstrated. To further improve the sensitivity of the Peano-shaped sensor, a multi-layer Peano sensor is developed, exhibiting remarkably enhanced sensitivity while maintaining low hysteresis. Overall, the developed LM-based microfluidic strain sensors enrolling Peano fractal geometry hold high potential for various wearable electronics applications.
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Affiliation(s)
- Yuli Luo
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Hao Fan
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Xiangjie Lai
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Zu'an Zeng
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Xingzi Lan
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Peiran Lin
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Linjun Tang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Wenlong Wang
- School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Yong Chen
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, Paris, 75005, France
| | - Yadong Tang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China.
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4
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Torres-Hoyos F, Hernández-Ortega F, Baena-Navarro R, Pinedo-López J. Liver cancer: A geometric approach to fractals and scaling analysis. Appl Radiat Isot 2024; 204:111123. [PMID: 38113664 DOI: 10.1016/j.apradiso.2023.111123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 10/13/2023] [Accepted: 11/21/2023] [Indexed: 12/21/2023]
Abstract
In the study of liver cancer, invasive techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) are used. In the present work, an in vivo 3D study will be carried out using MRI and CT images, using scaling dynamics, that is, calculating critical exponents of local roughness and fractal dimension. The results obtained for stages IA, IIA, and IIIA in liver cancer correspond to what was proposed by F. Family and T. Vicsek (1991).
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Affiliation(s)
- Francisco Torres-Hoyos
- Department of Physics, Faculty of Basic Sciences, Universidad de Córdoba, Montería, Colombia; Systems Engineering Program, Faculty of Engineering, Universidad Cooperativa de Colombia, Montería, Colombia.
| | | | - Rubén Baena-Navarro
- Department of Systems Engineering, Faculty of Engineering, Universidad de Córdoba, Montería, Colombia; Systems Engineering Program, Faculty of Engineering, Universidad Cooperativa de Colombia, Montería, Colombia
| | - Jhon Pinedo-López
- Faculty of Administrative, Accounting and Related Sciences, Universidad Cooperativa de Colombia, Montería, Colombia
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Alsaeedi AH, Al-Mahmood HHR, Alnaseri ZF, Aziz MR, Al-Shammary D, Ibaida A, Ahmed K. Fractal feature selection model for enhancing high-dimensional biological problems. BMC Bioinformatics 2024; 25:12. [PMID: 38195379 PMCID: PMC10775438 DOI: 10.1186/s12859-023-05619-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/15/2023] [Indexed: 01/11/2024] Open
Abstract
The integration of biology, computer science, and statistics has given rise to the interdisciplinary field of bioinformatics, which aims to decode biological intricacies. It produces extensive and diverse features, presenting an enormous challenge in classifying bioinformatic problems. Therefore, an intelligent bioinformatics classification system must select the most relevant features to enhance machine learning performance. This paper proposes a feature selection model based on the fractal concept to improve the performance of intelligent systems in classifying high-dimensional biological problems. The proposed fractal feature selection (FFS) model divides features into blocks, measures the similarity between blocks using root mean square error (RMSE), and determines the importance of features based on low RMSE. The proposed FFS is tested and evaluated over ten high-dimensional bioinformatics datasets. The experiment results showed that the model significantly improved machine learning accuracy. The average accuracy rate was 79% with full features in machine learning algorithms, while FFS delivered promising results with an accuracy rate of 94%.
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Affiliation(s)
- Ali Hakem Alsaeedi
- College of Computer Science and Information Technology, University of Al-Qadisiyah, Diwaniyah, 58009, Iraq.
- Department of Computer Techniques, Imam Kadhum College, Diwaniyah, 58009, Iraq.
| | | | - Zainab Fahad Alnaseri
- College of Computer Science and Information Technology, University of Al-Qadisiyah, Diwaniyah, 58009, Iraq
| | - Mohammad R Aziz
- College of Computer Science and Information Technology, University of Al-Qadisiyah, Diwaniyah, 58009, Iraq
| | - Dhiah Al-Shammary
- College of Computer Science and Information Technology, University of Al-Qadisiyah, Diwaniyah, 58009, Iraq
| | - Ayman Ibaida
- Intelligent Technology Innovation Lab, Victoria University, Melbourne, VIC, Australia
| | - Khandakar Ahmed
- Intelligent Technology Innovation Lab, Victoria University, Melbourne, VIC, Australia.
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Chen BH, Jiang WY, Zheng JY, Dai YS, Shi RY, Wu R, An DA, Tang LL, Xu JR, Zhao L, Wu LM. Prognostic value of right ventricular trabecular complexity in patients with arrhythmogenic cardiomyopathy. Eur Radiol 2024:10.1007/s00330-023-10561-y. [PMID: 38189980 DOI: 10.1007/s00330-023-10561-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 12/07/2023] [Accepted: 12/14/2023] [Indexed: 01/09/2024]
Abstract
OBJECTIVES The present study aimed to investigate the incremental prognostic value of the right ventricular fractal dimension (FD), a novel marker of myocardial trabecular complexity by cardiac magnetic resonance (CMR) in patients with arrhythmogenic cardiomyopathy (ACM). METHODS Consecutive patients with ACM undergoing CMR were followed up for major cardiac events, including sudden cardiac death, aborted cardiac arrest, and appropriate implantable cardioverter defibrillator intervention. Prognosis prediction was compared by Cox regression analysis. We established a multivariable model supplemented with RV FD and evaluated its discrimination by Harrell's C-statistic. We compared the category-free, continuous net reclassification improvement (cNRI) and integrated discrimination index (IDI) before and after the addition of FD. RESULTS A total of 105 patients were prospectively included from three centers and followed up for a median of 60 (48, 66) months; experienced 36 major cardiac events were recorded. Trabecular FD displayed a strong unadjusted association with major cardiac events (p < 0.05). In the multivariable Cox regression analysis, RV maximal apical FD maintained an independent association with major cardiac events (hazard ratio, 1.31 (1.11-1.55), p < 0.002). The Hosmer-Lemeshow goodness of fit test displayed good fit (X2 = 0.68, p = 0.99). Diagnostic performance was significantly improved after the addition of RV maximal apical FD to the multivariable baseline model, and the continuous net reclassification improvement increased 21% (p = 0.001), and the integrated discrimination index improved 16% (p = 0.045). CONCLUSIONS In patients with ACM, CMR-assessed myocardial trabecular complexity was independently correlated with adverse cardiovascular events and provided incremental prognostic value. CLINICAL RELEVANCE STATEMENT The application of FD values for assessing RV myocardial trabeculae may become an accessible and promising parameter in monitoring and early diagnosis of risk factors for adverse cardiovascular events in patients with ACM. KEY POINTS • Ventricular trabecular morphology, a novel quantitative marker by CMR, has been explored for the first time to determine the severity of ACM. • Patients with higher maximal apical fractal dimension of RV displayed significantly higher cumulative incidence of major cardiac events. • RV maximal apical FD was independently associated with major cardiac events and provided incremental prognostic value in patients with ACM.
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Affiliation(s)
- Bing-Hua Chen
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China
| | - Wen-Yi Jiang
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China
| | - Jin-Yu Zheng
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China
| | - Yi-Si Dai
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China
| | - Ruo-Yang Shi
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China
| | - Rui Wu
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China
| | - Dong-Aolei An
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China
| | - Lang-Lang Tang
- Department of Radiology, Longyan First Hospital, Affiliated to Fujian Medical University, Longyan, 364000, People's Republic of China
| | - Jian-Rong Xu
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China
| | - Lei Zhao
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 2nd Anzhen Road, Chaoyang District, Beijing, 100029, People's Republic of China.
| | - Lian-Ming Wu
- Department of Radiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200127, People's Republic of China.
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7
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Di Ieva A. Computational and Translational Fractal-Based Analysis in the Translational Neurosciences: An Overview. Adv Neurobiol 2024; 36:781-793. [PMID: 38468063 DOI: 10.1007/978-3-031-47606-8_39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
After the previous sections on "Fractals: What and Why?," the last section of this book covers the software tools necessary to perform computational fractal-based analysis, with special emphasis on its applications into the neurosciences. The use of ImageJ and MATLAB, as well as other software packages, is reviewed. The current and future applications of fractal modeling in bioengineering and biotechnology are discussed as well. Perspectives on the translation of merging fractals with artificial intelligence-based methods with the final aim of pattern discrimination in neurological diseases by means of a unified fractal model of the brain are also given. Moreover, some new translational applications of fractal analysis to the neurosciences are presented, including eye tracking analysis, cognitive neuroscience, and music.
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Affiliation(s)
- Antonio Di Ieva
- Computational NeuroSurgery (CNS) Lab & Macquarie Neurosurgery, Macquarie Medical School, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, Australia.
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8
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Wolfson SS, Kirk I, Waldie K, King C. EEG Complexity Analysis of Brain States, Tasks and ASD Risk. Adv Neurobiol 2024; 36:733-759. [PMID: 38468061 DOI: 10.1007/978-3-031-47606-8_37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Autism spectrum disorder is an increasingly prevalent and debilitating neurodevelopmental condition and an electroencephalogram (EEG) diagnostic challenge. Despite large amounts of electrophysiological research over many decades, an EEG biomarker for autism spectrum disorder (ASD) has not been found. We hypothesized that reductions in complex dynamical system behaviour in the human central nervous system as part of the macroscale neuronal function during cognitive processes might be detectable in whole EEG for higher-risk ASD adults. In three studies, we compared the medians of correlation dimension, largest Lyapunov exponent, Higuchi's fractal dimension, multiscale entropy, multifractal detrended fluctuation analysis and Kolmogorov complexity during resting, cognitive and social skill tasks in 20 EEG channels of 39 adults over a range of ASD risk. We found heterogeneous complexity distribution with clusters of hierarchical sequences pointing to potential cognitive processing differences, but no clear distinction based on ASD risk. We suggest that there is indication of statistically significant differences between complexity measures of brain states and tasks. Though replication of our studies is needed with a larger sample, we believe that our electrophysiological and analytic approach has potential as a biomarker for earlier ASD diagnosis.
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Affiliation(s)
- Stephen S Wolfson
- The University of Auckland School of Psychology, Auckland, Auckland, New Zealand.
| | - Ian Kirk
- The University of Auckland School of Psychology, Auckland, Auckland, New Zealand
| | - Karen Waldie
- The University of Auckland School of Psychology, Auckland, Auckland, New Zealand
| | - Chris King
- The University of Auckland School of Psychology, Auckland, Auckland, New Zealand
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9
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Newport RA, Liu S, Di Ieva A. Analyzing Eye Paths Using Fractals. Adv Neurobiol 2024; 36:827-848. [PMID: 38468066 DOI: 10.1007/978-3-031-47606-8_42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Visual patterns reflect the anatomical and cognitive background underlying process governing how we perceive information, influenced by stimulus characteristics and our own visual perception. These patterns are both spatially complex and display self-similarity seen in fractal geometry at different scales, making them challenging to measure using the traditional topological dimensions used in Euclidean geometry.However, methods for measuring eye gaze patterns using fractals have shown success in quantifying geometric complexity, matchability, and implementation into machine learning methods. This success is due to the inherent capabilities that fractals possess when reducing dimensionality using Hilbert curves, measuring temporal complexity using the Higuchi fractal dimension (HFD), and determining geometric complexity using the Minkowski-Bouligand dimension.Understanding the many applications of fractals when measuring and analyzing eye gaze patterns can extend the current growing body of knowledge by identifying markers tied to neurological pathology. Additionally, in future work, fractals can facilitate defining imaging modalities in eye tracking diagnostics by exploiting their capability to acquire multiscale information, including complementary functions, structures, and dynamics.
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Affiliation(s)
- Robert Ahadizad Newport
- Computational NeuroSurgery (CNS) Lab, Macquarie Medical School, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Sidong Liu
- Computational NeuroSurgery (CNS) Lab, Macquarie Medical School, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Antonio Di Ieva
- Computational NeuroSurgery (CNS) Lab, Macquarie Medical School, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, Australia
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10
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Casey DT, Lahue KG, Mori V, Herrmann J, Hall JK, Suki B, Janssen-Heininger YMW, Bates JHT. Local fractal dimension of collagen detects increased spatial complexity in fibrosis. Histochem Cell Biol 2024; 161:29-42. [PMID: 37938346 PMCID: PMC10794291 DOI: 10.1007/s00418-023-02248-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2023] [Indexed: 11/09/2023]
Abstract
Increase of collagen content and reorganization characterizes fibrosis but quantifying the latter remains challenging. Spatially complex structures are often analyzed via the fractal dimension; however, established methods for calculating this quantity either provide a single dimension for an entire object or a spatially distributed dimension that only considers binary images. These neglect valuable information related to collagen density in images of fibrotic tissue. We sought to develop a fractal analysis that can be applied to 3-dimensional (3D) images of fibrotic tissue. A fractal dimension map for each image was calculated by determining a single fractal dimension for a small area surrounding each image pixel, using fiber thickness as the third dimension. We found that this local fractal dimension increased with age and with progression of fibrosis regardless of collagen content. Our new method of distributed 3D fractal analysis can thus distinguish between changes in collagen content and organization induced by fibrosis.
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Affiliation(s)
- Dylan T Casey
- Department of Medicine, University of Vermont Larner College of Medicine, 149 Beaumont Ave, Burlington, VT, 05405, USA.
- Complex Systems Center, University of Vermont, Burlington, VT, USA.
| | - Karolyn G Lahue
- Department of Pathology and Laboratory Medicine, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Vitor Mori
- Department of Medicine, University of Vermont Larner College of Medicine, 149 Beaumont Ave, Burlington, VT, 05405, USA
| | - Jacob Herrmann
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
| | - Joseph K Hall
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Béla Suki
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Yvonne M W Janssen-Heininger
- Department of Pathology and Laboratory Medicine, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Jason H T Bates
- Department of Medicine, University of Vermont Larner College of Medicine, 149 Beaumont Ave, Burlington, VT, 05405, USA
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Iglesias-Parro S, Soriano MF, Ibáñez-Molina AJ. Advances in Understanding Fractals in Affective and Anxiety Disorders. Adv Neurobiol 2024; 36:717-732. [PMID: 38468060 DOI: 10.1007/978-3-031-47606-8_36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
In this chapter, we review the research that has applied fractal measures to the study of the most common psychological disorders, that is, affective and anxiety disorders. Early studies focused on heart rate, but diverse measures have also been examined, from variations in subjective mood, or hand movements, to electroencephalogram or magnetoencephalogram data. In general, abnormal fractal dynamics in different physiological and behavioural outcomes have been observed in mental disorders. Despite the disparity of variables measured, fractal analysis has shown high sensitivity in discriminating patients from healthy controls. However, and because of this heterogeneity in measures, the results are not straightforward, and more studies are needed in this promising line.
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Affiliation(s)
| | - Maria Felipa Soriano
- Department of Mental Health Service, Hospital San Agustín de Linares, Linares, Spain
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12
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Di Ieva A. Fractals in Neuroanatomy and Basic Neurosciences: An Overview. Adv Neurobiol 2024; 36:141-147. [PMID: 38468030 DOI: 10.1007/978-3-031-47606-8_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The introduction of fractal geometry to the neurosciences has been a major paradigm shift over the last decades as it has helped overcome approximations and limitations that occur when Euclidean and reductionist approaches are used to analyze neurons or the entire brain. Fractal geometry allows for quantitative analysis and description of the geometric complexity of the brain, from its single units to the neuronal networks.As illustrated in the second section of this book, fractal analysis provides a quantitative tool for the study of the morphology of brain cells (i.e., neurons and microglia) and its components (e.g., dendritic trees, synapses), as well as the brain structure itself (cortex, functional modules, neuronal networks). The self-similar logic which generates and shapes the different hierarchical systems of the brain and even some structures related to its "container," that is, the cranial sutures on the skull, is widely discussed in the following chapters, with a link between the applications of fractal analysis to the neuroanatomy and basic neurosciences to the clinical applications discussed in the third section.
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Affiliation(s)
- Antonio Di Ieva
- Computational NeuroSurgery (CNS) Lab & Macquarie Neurosurgery, Macquarie Medical School, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, Australia.
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13
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Karperien AL, Jelinek HF. Box-Counting Fractal Analysis: A Primer for the Clinician. Adv Neurobiol 2024; 36:15-55. [PMID: 38468026 DOI: 10.1007/978-3-031-47606-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
This chapter lays out the elementary principles of fractal geometry underpinning much of the rest of this book. It assumes a minimal mathematical background, defines the key principles and terms in context, and outlines the basics of a fractal analysis method known as box counting and how it is used to perform fractal, lacunarity, and multifractal analyses. As a standalone reference, this chapter grounds the reader to be able to understand, evaluate, and apply essential methods to appreciate and heal the exquisitely detailed fractal geometry of the brain.
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Affiliation(s)
| | - Herbert F Jelinek
- Department of Medical Sciences and Biotechnology Center, Khalifa University, Abu Dhabi, UAE
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14
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Kołodziej M, Waliszewski P. Neuronal Fractal Dynamics. Adv Neurobiol 2024; 36:191-201. [PMID: 38468033 DOI: 10.1007/978-3-031-47606-8_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Synapse formation is a unique biological phenomenon. The molecular biological perspective of this phenomenon is different from the fractal geometrical one. However, these perspectives are not mutually exclusive and supplement each other. The cornerstone of the first one is a chain of biochemical reactions with the Markov property, that is, a deterministic, conditional, memoryless process ordered in time and in space, in which the consecutive stages are determined by the expression of some regulatory proteins. The coordination of molecular and cellular events leading to synapse formation occurs in fractal time space, that is, the space that is not only the arena of events but also actively influences those events. This time space emerges owing to coupling of time and space through nonlinear dynamics. The process of synapse formation possesses fractal dynamics with non-Gaussian distribution of probability and a reduced number of molecular Markov chains ready for transfer of biologically relevant information.
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15
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Policarpo JMP, Ramos AAGF, Dye C, Faria NR, Leal FE, Moraes OJS, Parag KV, Peixoto PS, Buss L, Sabino EC, Nascimento VH, Deppman A. Scale-free dynamics of COVID-19 in a Brazilian city. Appl Math Model 2023; 121:166-184. [PMID: 37151217 PMCID: PMC10154131 DOI: 10.1016/j.apm.2023.03.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 03/13/2023] [Accepted: 03/29/2023] [Indexed: 05/09/2023]
Abstract
A common basis to address the dynamics of directly transmitted infectious diseases, such as COVID-19, are compartmental (or SIR) models. SIR models typically assume homogenous population mixing, a simplification that is convenient but unrealistic. Here we validate an existing model of a scale-free fractal infection process using high-resolution data on COVID-19 spread in São Caetano, Brazil. We find that transmission can be described by a network in which each infectious individual has a small number of susceptible contacts, of the order of 2-5. This model parameter correlated tightly with physical distancing measured by mobile phone data, such that in periods of greater distancing the model recovered a lower average number of contacts, and vice versa. We show that the SIR model is a special case of our scale-free fractal process model in which the parameter that reflects population structure is set at unity, indicating homogeneous mixing. Our more general framework better explained the dynamics of COVID-19 in São Caetano, used fewer parameters than a standard SIR model and accounted for geographically localized clusters of disease. Our model requires further validation in other locations and with other directly transmitted infectious agents.
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Affiliation(s)
| | - A A G F Ramos
- Instituto de Física - Universidade de São Paulo, Brazil
| | - C Dye
- Department of Biology, University of Oxford, UK
| | - N R Faria
- Department of Biology, University of Oxford, UK
- Imperial Coll London, MRC Ctr Global Infect Dis Anal, Sch Publ Helth, London, England, UK
- Faculdade de Medicina - Universidade de São Paulo, Brazil
| | - F E Leal
- Universidade de São Caetano do Sul, São Caetano do Sul and Programa de Oncovirologia - Instituto Nacional de Câncer, Rio de Janeiro, Brazil
| | - O J S Moraes
- Instituto de Física - Universidade de São Paulo, Brazil
| | - K V Parag
- MRC Centre for Global Infectious Disease Analysis, J-IDEA, Imperial College London, London W2 1PG, UK
| | - P S Peixoto
- Instituto de Matemática e Estatística, Universidade de São Paulo, Brazil
| | - L Buss
- Faculdade de Medicina - Universidade de São Paulo, Brazil
| | - E C Sabino
- Faculdade de Medicina - Universidade de São Paulo, Brazil
| | | | - A Deppman
- Instituto de Física - Universidade de São Paulo, Brazil
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16
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Kelty-Stephen DG, Lane E, Bloomfield L, Mangalam M. Multi fractal test for nonlinearity of interactions across scales in time series. Behav Res Methods 2023; 55:2249-2282. [PMID: 35854196 DOI: 10.3758/s13428-022-01866-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2022] [Indexed: 01/21/2023]
Abstract
The creativity and emergence of biological and psychological behavior tend to be nonlinear, and correspondingly, biological and psychological measures contain degrees of irregularity. The linear model might fail to reduce these measurements to a sum of independent random factors (yielding a stable mean for the measurement), implying nonlinear changes over time. The present work reviews some of the concepts implicated in nonlinear changes over time and details the mathematical steps involved in their identification. It introduces multifractality as a mathematical framework helpful in determining whether and to what degree the measured series exhibits nonlinear changes over time. These mathematical steps include multifractal analysis and surrogate data production for resolving when multifractality entails nonlinear changes over time. Ultimately, when measurements fail to fit the structures of the traditional linear model, multifractal modeling allows for making those nonlinear excursions explicit, that is, to come up with a quantitative estimate of how strongly events may interact across timescales. This estimate may serve some interests as merely a potentially statistically significant indicator of independence failing to hold, but we suspect that this estimate might serve more generally as a predictor of perceptuomotor or cognitive performance.
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Affiliation(s)
| | - Elizabeth Lane
- Department of Psychiatry, University of California-San Diego, San Diego, CA, USA
| | | | - Madhur Mangalam
- Department of Physical Therapy, Movement and Rehabilitation Sciences, Northeastern University, Boston, MA, USA.
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17
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Don S. Computer-aided Diagnosis of Polyp Classification Using Scale Invariant Features and Extreme Gradient Boosting. J Med Phys 2023; 48:230-237. [PMID: 37969147 PMCID: PMC10642600 DOI: 10.4103/jmp.jmp_29_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 11/17/2023] Open
Abstract
Aims Analysis of colonoscopy images is an important diagnostic procedure in the identification of colorectal cancer. It has been observed that owing to advancements in technology, numerous machine-learning models now excel in the analysis of colorectal polyps classification. This work focused on developing a framework that can classify polyps using images during colonoscopy. Materials and Methods First, the images were corrected by removing their spectral reflection. Second, feature pools were obtained by applying Radon transform (θ=45, 90, 135, and 180). From the Radon transform, fractal dimension was calculated as a feature vector combined with Zernike moment obtained from the Zernike features. Finally, Extreme Gradient Boosting (XGBoost) algorithm was applied for the classification and to compare it with state-of-the-art methods. Results The experimental results obtained with the proposed framework have been reported, cross-validated, and discussed. The proposed method gives a classification accuracy of 93% for light XGBoost and 92% for XGBoost. Conclusion This study shows that by applying scale invariant features over a small dataset, XGBoost outperforms state-of-the-art methods when it comes to polyp classification.
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Affiliation(s)
- S. Don
- Department of Computer Science and Applications, Amrita School of Computing, Amrita Vishwa Vidyapeetham, Kollam, Kerala, India
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18
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Li Y, Liu W, Song D, Ren Z, Wang H, Guo X. Full-scale pore characteristics in coal and their influence on the adsorption capacity of coalbed methane. Environ Sci Pollut Res Int 2023:10.1007/s11356-023-27298-2. [PMID: 37166730 DOI: 10.1007/s11356-023-27298-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/24/2023] [Indexed: 05/12/2023]
Abstract
Coalbed methane (CBM) is primarily stored and transported through the pores in the coal matrix, making it essential to study the development of different scales of pores in coal to better understand the evaluation and exploration of CBM. In this study, four coal samples of varying ranks (Ro,max = 0.68%-2.86%) were selected, and different scale pores were obtained through low-pressure CO2 and Ar adsorption (LP-CO2/ArGA) and mercury intrusion porosimetry (MIP) experiments. A full-scale pore evaluation model was established, and the impact of pores on methane adsorption and restriction was analyzed and discussed through high-pressure adsorption experiments. Our results show that (1) at high pressures (> 100 MPa), the MIP technique caused pore compression and overestimated the pore size below 30 nm by up to 47.2%; (2) to obtain a comprehensive pore evaluation, we developed an accurate model that combines LP-CO2/ArGA with NLDFT and BJH and NLDFT models to determine micropore (0.3-1.5 nm) and mesopore (1.5-30 nm) parameters. By combining this model with MIP test results, we can obtain a full-scale pore size in the range of 0.3 nm-200 μm; (3) coal rank affected the development of full-scale pore characteristics. As coal rank increased, the specific surface area (SSA) of micropores and adsorption capacity of methane first decreased, then increased. Micropores were found to be the most important storage space for CBM and control gas adsorption, with a microporous SSA and PV to total SSA and total PV ratio of 97.93% and 63.69%, respectively. (4) We also observed a significant linear relationship between the fractal dimension of micropores and the Langmuir volume (VL) based on fractal theory. As the fractal dimension increased, VL also increased (R2 = 0.8581), indicating that VL is controlled by the complexity of micropores, which is consistent with the comprehensive evaluation index (Dt) and VL (R2 = 0.8744). Based on our predicted model, VL can be estimated using the SSA of micropores and Dt. Our findings shed light on the relationship between pore morphology and CBM occurrence and have practical implications for fields such as catalytic synthesis, E-CBM, and gas purification.
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Affiliation(s)
- Yunbo Li
- Institute of Resource & Environment, Henan Polytechnic University, Jiaozuo, 454000, China.
| | - Wen Liu
- Institute of Resource & Environment, Henan Polytechnic University, Jiaozuo, 454000, China
| | - Dangyu Song
- Institute of Resource & Environment, Henan Polytechnic University, Jiaozuo, 454000, China
| | - Zixian Ren
- Institute of Resource & Environment, Henan Polytechnic University, Jiaozuo, 454000, China
| | - Haifeng Wang
- Institute of Resource & Environment, Henan Polytechnic University, Jiaozuo, 454000, China
| | - Xingxin Guo
- Institute of Resource & Environment, Henan Polytechnic University, Jiaozuo, 454000, China
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19
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Pikovsky A, Tsimring LS. Statistical theory of asymmetric damage segregation in clonal cell populations. Math Biosci 2023; 358:108980. [PMID: 36804386 DOI: 10.1016/j.mbs.2023.108980] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 12/07/2022] [Accepted: 02/13/2023] [Indexed: 02/19/2023]
Abstract
Asymmetric damage segregation (ADS) is ubiquitous among unicellular organisms: After a mother cell divides, its two daughter cells receive sometimes slightly, sometimes strongly different fractions of damaged proteins accumulated in the mother cell. Previous studies demonstrated that ADS provides a selective advantage over symmetrically dividing cells by rejuvenating and perpetuating the population as a whole. In this work we focus on the statistical properties of damage in individual lineages and the overall damage distributions in growing populations for a variety of ADS models with different rules governing damage accumulation, segregation, and the lifetime dependence on damage. We show that for a large class of deterministic ADS rules the trajectories of damage along the lineages are chaotic, and the distributions of damage in cells born at a given time asymptotically becomes fractal. By exploiting the analogy of linear ADS models with the Iterated Function Systems known in chaos theory, we derive the Frobenius-Perron equation for the stationary damage density distribution and analytically compute the damage distribution moments and fractal dimensions. We also investigate nonlinear and stochastic variants of ADS models and show the robustness of the salient features of the damage distributions.
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Affiliation(s)
- Arkady Pikovsky
- Department of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24/25, 14476, Potsdam-Golm, Germany.
| | - Lev S Tsimring
- Synthetic Biology Institute, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0328, USA.
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20
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Pikovsky A, Tsimring LS. Statistical Theory of Asymmetric Damage Segregation in Clonal Cell Populations. ArXiv 2023:arXiv:2302.08071v1. [PMID: 36824426 PMCID: PMC9949173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Asymmetric damage segregation (ADS) is ubiquitous among unicellular organisms: After a mother cell divides, its two daughter cells receive sometimes slightly, sometimes strongly different fractions of damaged proteins accumulated in the mother cell. Previous studies demonstrated that ADS provides a selective advantage over symmetrically dividing cells by rejuvenating and perpetuating the population as a whole. In this work we focus on the statistical properties of damage in individual lineages and the overall damage distributions in growing populations for a variety of ADS models with different rules governing damage accumulation, segregation, and the lifetime dependence on damage. We show that for a large class of deterministic ADS rules the trajectories of damage along the lineages are chaotic, and the distributions of damage in cells born at a given time asymptotically becomes fractal. By exploiting the analogy of linear ADS models with the Iterated Function Systems known in chaos theory, we derive the Frobenius-Perron equation for the stationary damage density distribution and analytically compute the damage distribution moments and fractal dimensions. We also investigate nonlinear and stochastic variants of ADS models and show the robustness of the salient features of the damage distributions.
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Affiliation(s)
- Arkady Pikovsky
- Department of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24/25, 14476, Potsdam-Golm, Germany
| | - Lev S. Tsimring
- BioCircuits Institute, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0328, USA
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21
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Liu C, Liang J, Li Y, Shi K. Fractal analysis of impact of PM 2.5 on surface O 3 sensitivity regime based on field observations. Sci Total Environ 2023; 858:160136. [PMID: 36375545 DOI: 10.1016/j.scitotenv.2022.160136] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 06/16/2023]
Abstract
Properties of PM2.5 that can change aerosol chemistry and photolysis rates have great impacts on O3 sensitivity regime, further affecting the production rate of surface O3. However, responses of O3 sensitivity regime to changes in PM2.5 levels are difficult to be accurately determined, due to the complexity and nonlinearity of atmospheric chemistry. Here, based on long-term time series (2016-2020) of air quality variables in north and south Taiwan, fractal analysis along with Pearson correlation analysis are used to directly reveal the impacts of PM2.5 on O3 sensitivity regime in real atmosphere, by capturing the nonlinear dynamic relations among air pollutants. Great regional and seasonal difference in impacts of PM2.5 on O3 sensitivity regime may be ascribed to meteorological factors, PM2.5 components and levels of SO2, NO, NO2, etc. For north Taiwan, increased PM2.5 level can enhance the sensitivity of O3 formation to VOC in spring and summer, whereas the opposite effect can be observed in winter. But for south Taiwan, the influence of PM2.5 on O3 sensitivity regime is not statistically significant, excluding spring. Furthermore, feasibility and availability of fractal analysis is tested by simulations with Empirical Kinetics Modeling Approach (EKMA). The results demonstrate the capability of fractal analysis to identify the impacts of PM2.5 on O3 sensitivity regime in real atmosphere, which can provide suggestions for PM2.5-O3 coordinated control strategies in regions suffering combined air pollution.
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Affiliation(s)
- Chunqiong Liu
- College of Environmental Sciences and Engineering, China West Normal University, Nanchong, Sichuan, China; Key Laboratory of Nanchong City of Ecological Environment Protection and Pollution Prevention in Jialing River Basin, China West Normal University, Nanchong, China; College of Biology and Environmental Sciences, Jishou University, Jishou, Hunan, China
| | - Juan Liang
- College of Architecture & Environment, Sichuan University, Chengdu, China
| | - Youping Li
- College of Environmental Sciences and Engineering, China West Normal University, Nanchong, Sichuan, China; Key Laboratory of Nanchong City of Ecological Environment Protection and Pollution Prevention in Jialing River Basin, China West Normal University, Nanchong, China
| | - Kai Shi
- College of Environmental Sciences and Engineering, China West Normal University, Nanchong, Sichuan, China; Key Laboratory of Nanchong City of Ecological Environment Protection and Pollution Prevention in Jialing River Basin, China West Normal University, Nanchong, China.
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22
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Trescher TF, da Silva RJ, Souto PCS, Silva JR, de Souza NC. Growth models of fractal interfaces in the description of microorganism colony growth: effect of photodynamic inactivation. Photochem Photobiol Sci 2023; 22:311-318. [PMID: 36216976 DOI: 10.1007/s43630-022-00315-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/26/2022] [Indexed: 11/24/2022]
Abstract
Candida albicans is responsible for most of the nosocomial infections that affect immunocompromised individuals. We investigated the application of eosin in photodynamic inactivation as a strategy in the inhibition of the growth of C. albicans and the morphological variation and growth dynamics in light of fractal theory. The damage caused to fungal structures alters the roughness of the colony, and these changes were described by parameters that were defined by mathematical models. Proliferation of the fungi should be inhibited in the center of the colonies and the analysis of the edges gives an indication about the dynamics of growth and cell reproduction.
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Affiliation(s)
- Tarquin F Trescher
- Grupo de Materiais Nanoestruturados, Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso, Brazil
| | - Romário J da Silva
- Grupo de Materiais Nanoestruturados, Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso, Brazil
| | - Paula C S Souto
- Grupo de Materiais Nanoestruturados, Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso, Brazil
| | - Josmary R Silva
- Grupo de Materiais Nanoestruturados, Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso, Brazil
| | - Nara C de Souza
- Grupo de Materiais Nanoestruturados, Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso, Brazil. .,Laboratório de Nanosistemas E Tecnologias, Universidade Federal de Goiás, Aparecida de Goiânia, Goiás, Brazil.
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23
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Mear E, Gladwell V, Pethick J. Knee extensor force control as a predictor of dynamic balance in healthy adults. Gait Posture 2023; 100:230-235. [PMID: 36638669 DOI: 10.1016/j.gaitpost.2023.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 09/06/2022] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
BACKGROUND Previous research has demonstrated that force control in various muscles of the lower limb (measured according to the magnitude of force fluctuations) explains significant variance in static balance. Given the dynamic nature of many functional activities and sports, assessment of balance and its determinants under dynamic conditions is of importance. RESEARCH QUESTION Does muscle force control explain significant variance in dynamic balance, as measured using the Y balance test (YBT)? METHODS YBT performance and knee extensor muscle force control were measured in 28 healthy participants. The YBT involved stance on the right leg and attempting maximal reach with the left leg in the anterior, posteromedial, and posterolateral directions. Force control was assessed during isometric knee extension contractions of the right leg at 10%, 20% and 40% maximal voluntary contraction (MVC) and was quantified according to the magnitude (using the coefficient of variation [CV]), and the temporal structure (using sample entropy, SampEn; and detrended fluctuation analysis α), of force fluctuations. RESULTS Significant correlations were observed for YBT anterior reach and muscle force CV (r = -0.44, P = 0.02) and SampEn (r = 0.47, P = 0.012) during contractions at 40% MVC. A subsequent regression model demonstrated that muscle force CV and SampEn at 40% MVC significantly explained 54% of variance in YBT anterior reach. Significant correlations were also observed for YBT posteromedial reach and MVC (r = 0.39, P = 0.043) and muscle force CV during contractions at 40% MVC (r = -0.51, P = 0.006). The regression model demonstrated that MVC and muscle force CV at 40% MVC significantly explained 53.9% of variance in YBT posteromedial reach. SIGNIFICANCE These results are the first to indicate that a moderate amount of variance in dynamic balance can be explained by measures of isometric force control.
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Affiliation(s)
- Emily Mear
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Essex, UK
| | - Valerie Gladwell
- Institute of Health and Wellbeing, University of Suffolk, Suffolk, UK
| | - Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Essex, UK.
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24
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Sun J, Liu G, Yuan X. Alternative stable state and its evaluation in wetland reconstruction based on landscape design. Sci Total Environ 2023; 857:159642. [PMID: 36302400 DOI: 10.1016/j.scitotenv.2022.159642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 10/13/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
An alternative stable state is closely related to the health and sustainable development of ecosystems; however, knowledge of the alternative stable state and its quantitative evaluation in wetland reconstruction remains incomplete. In this study, we used landscape design to reconstruct an optimized ecological polder wetland and a lake wetland in the Yunmeng Marsh area, China, and the alternative stable states of the two wetland ecosystems were assessed from an ecosystem perspective via emergy/eco-exergy and fractal dimensions. The emergy densities for the optimized ecological polder wetland and the lake wetland were 2.35E+13 sej yr-1 m-3 and 2.18E+13 sej m-3, and the emergy sustainability index (ESI) values were 216.57 and 193.31, respectively, indicating that the reconstructed wetland ecosystems were dominated by renewable energy flows and were highly sustainable. The eco-exergy density and emergy/eco-exergy ratio results showed that natural selection self-organized the reconstructed wetland ecosystems to tolerate environmental stresses and changes. In addition, the fractal dimensions of the morphology and contour of the polder wetland, which reflect the space occupation capacity of geometric and physical constraints in the wetland, were 1.57 and 1.75, and those of the lake wetland were 1.03 and 1.47, respectively. The synthetic evaluation results showed that the alternative stable states of both the optimized ecological polder wetland ecosystem and the lake wetland ecosystem were ecofriendly modes of wetland reconstruction, which can be implemented together to create a "lake-polder" ecosystem. Our study on the alternative stable states of wetland ecosystems is helpful for exploring the synergistic symbiosis between traditional culture and the ecological environment in China and other wetland-rich regions and countries with severe disturbances.
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Affiliation(s)
- Jinfang Sun
- College of Geography and Tourism, Qufu Normal University, Rizhao 276826, China.
| | - Guodong Liu
- College of Geography and Tourism, Qufu Normal University, Rizhao 276826, China
| | - Xingzhong Yuan
- Faculty of Architecture and Urban Planning, Chongqing University, Chongqing 400030, China; Key Laboratory of New Technology for Construction of Cities in Mountain Area, Chongqing University, Chongqing 400030, China
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25
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Sacco RG, Torday JS. Systems biology of human aging: A Fibonacci time series model. Prog Biophys Mol Biol 2023; 177:24-33. [PMID: 36265693 DOI: 10.1016/j.pbiomolbio.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 09/14/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022]
Abstract
Fractals are everywhere in nature, particularly at the interfaces where matter or energy must be transferred, since they maximize surface area while minimizing energy losses. Temporal fractals have been well studied at micro scales in human biology, but have received comparatively little attention at broader macro scales. In this paper, we describe a fractal time series model of human aging from a systems biology perspective. This model examines how intrinsic aging rates are shaped by entropy and Fibonacci fractal dynamics, with implications for the emergence of key life cycle traits. This proposition is supported by research findings. The finding of an intrinsic aging rate rooted in Fibonacci fractal dynamics represents a new predictive paradigm in evolutionary biology.
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26
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Wang S, Zhang Z, Huang X, Lei Q. A Numerical Study of Elastic Wave Arrival Behavior in a Naturally Fractured Rock Based on a Combined Displacement Discontinuity-Discrete Fracture Network Model. Rock Mech Rock Eng 2022; 56:2717-2736. [PMID: 37008575 PMCID: PMC10042930 DOI: 10.1007/s00603-022-03180-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 11/24/2022] [Indexed: 06/19/2023]
Abstract
The arrival behavior of elastic waves in a naturally fractured rock is studied based on numerical simulations. We use the discrete fracture network method to represent the distribution of a natural fracture system and employ the displacement discontinuity method to compute the propagation of elastic waves across individual fractures. We analyze macroscopic wavefield arrival properties collectively arising from the interaction between elastic waves and numerous fractures in the system. We show that the dimensionless angular frequency ῶ = ωZ/κ exerts a fundamental control on the arrival behavior of a plane wave traveling through the fractured rock, where ω, Z, and κ are the angular frequency, seismic impedance, and fracture stiffness, respectively. An asynchronous arrival phenomenon of the wave energy occurs and becomes more significant with an increased ῶ. Two regimes are identified according to the two-branch dependency of the fractal dimension D of the FFAW on ῶ, where the wave arrival behavior is within a non-fractal regime for ῶ smaller than the critical frequency ῶ c ≈ 1.0, and enters the fractal regime for ῶ ≥ ῶ c. The self-affine properties of the FFAW, i.e., the roughness exponent α and the correlation length l c, both linearly decrease as a function of the exponent ξ (with ῶ = 10 ξ ) in the fractal regime. Early breakthrough of wave transport occurs in regions with relatively low fracture density, while late-time arrival happens in regions of high fracture density.
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Affiliation(s)
- Shuaifeng Wang
- Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai, People’s Republic of China
- Key Laboratory of Geotechnical and Underground Engineering, Ministry of Education, Tongji University, Shanghai, People’s Republic of China
| | - Zixin Zhang
- Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai, People’s Republic of China
- Key Laboratory of Geotechnical and Underground Engineering, Ministry of Education, Tongji University, Shanghai, People’s Republic of China
| | - Xin Huang
- Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai, People’s Republic of China
- Key Laboratory of Geotechnical and Underground Engineering, Ministry of Education, Tongji University, Shanghai, People’s Republic of China
| | - Qinghua Lei
- Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai, People’s Republic of China
- Department of Earth Sciences, ETH Zürich, Zurich, Switzerland
- Department of Earth Sciences, Uppsala University, Uppsala, Sweden
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27
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Melo IO, Angelo Mendes Tenorio FDC, da Silva Gomes JA, da Silva Junior VA, de Albuquerque Nogueira R, Tenorio BM. Fractal methods applied to the seminiferous lumen images can quantify testicular changes induced by heat stress. Acta Histochem 2022; 124:151949. [PMID: 36007436 DOI: 10.1016/j.acthis.2022.151949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/03/2022] [Accepted: 08/05/2022] [Indexed: 11/25/2022]
Abstract
Male infertility affects many couples around the world and can be related to environmental factors such as exposure to high temperatures. Even so, automated methods evaluating the seminiferous tubules to detect testicular damage are still scarce. In search of new approaches to automation in the microscopic analysis of the testis; the present study used the fractal dimension, lacunarity, multifractality and quantitative morphometry to quantify changes in microphotographs of the seminiferous lumen in testicles reversibly damaged by heat stress (43 °C, 12 min). The parameters fractal dimension, lacunarity, multifractality (Dq and α), perimeter, feret and circularity were able to detect changes in the seminiferous lumen at 7, 15 and 30 days after the testicular damage. These methods also detected the recovery of spermatogenesis at 60 days after heat stress. Area, f(α), centroid X and Y, roundness, rectangle height and width were unable to detect changes caused by heat stress. In conclusion, computer assisted methods applied to the seminiferous lumen images can be a useful new viewpoint to analyze microscopic changes in the testicles, a fast low-cost tool to assist in the automated quantification of testicular damage.
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Affiliation(s)
- Isabel Oliveira Melo
- Health Sciences Center, Federal University of Paraíba, João Pessoa, Paraíba, Brazil
| | | | - José Anderson da Silva Gomes
- Department of Histology and Embryology, Bioscience Center, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | | | | | - Bruno Mendes Tenorio
- Department of Histology and Embryology, Bioscience Center, Federal University of Pernambuco, Recife, Pernambuco, Brazil.
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Wanliss JA, Wanliss GE. Efficient calculation of fractal properties via the Higuchi method. Nonlinear Dyn 2022; 109:2893-2904. [PMID: 35765369 PMCID: PMC9223273 DOI: 10.1007/s11071-022-07353-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 03/08/2022] [Indexed: 05/29/2023]
Abstract
Higuchi's method of determining fractal dimension is an important, well-used, research tool that, compared to many other methods, gives rapid, efficient, and robust estimations for the range of possible fractal dimensions. One major shortcoming in applying the method is the correct choice of tuning parameter (k max); a poor choice can generate spurious results, and there is no agreed upon methodology to solve this issue. We analyze multiple instances of synthetic fractal signals to minimize an error metric. This allows us to offer a new and general method that allows determination, a priori, of the best value for the tuning parameter, for a particular length data set. We demonstrate its use on physical data, by calculating fractal dimensions for a shell model of the nonlinear dynamics of MHD turbulence, and severe acute respiratory syndrome coronavirus 2 isolate Wuhan-Hu-1 from the family Coronaviridae.
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Affiliation(s)
- J. A. Wanliss
- Department of Physics, Presbyterian College, 503 S. Broad St., Clinton, SC 29325 USA
| | - Grace E. Wanliss
- Department of Physics, Presbyterian College, 503 S. Broad St., Clinton, SC 29325 USA
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Mackert V, Schroer MA, Winterer M. Unraveling agglomeration and deagglomeration in aqueous colloidal dispersions of very small tin dioxide nanoparticles. J Colloid Interface Sci 2022; 608:2681-93. [PMID: 34838316 DOI: 10.1016/j.jcis.2021.10.194] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/29/2021] [Accepted: 10/31/2021] [Indexed: 12/16/2022]
Abstract
HYPOTHESIS Understanding deagglomeration, agglomerate formation and structure for very small nanoparticles (NPs), due to their more facile agglomeration, is critical for processing or tailoring agglomerates for nanostructured materials. We propose that by controlling and fine-tuning the interplay of agglomeration (colloidal interaction) and deagglomeration (hydrodynamic forces), the design of agglomerate size, microstructure and morphology is possible even for very small NPs. EXPERIMENTS Here, we investigate very small SnO2 NPs (10 nm) generated in the gas phase as model system. Small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS) are used to study dispersions in aqueous media across the entire pH range (2-12) at various NaCl concentrations treated with ultrasound. Parallel to size and size distribution, agglomerate morphology and microstructure are analyzed by means of the mass fractal dimension, dm and modeled with ab initio shape simulations. The critical coagulation concentration (CCC) is determined for the alkaline region where the SnO2 NPs are highly charged. FINDINGS Quantitative analysis of SAXS and DLS data reveals that size and size distribution of the agglomerates depend similarly on the electrostatic interaction influenced by pH and salinity as observed by the zeta potential. In contrast dm is mainly influenced by the salt concentration. Ab initio shape simulations support these experimental findings.
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Rawls E, White R, Kane S, Stevens CE, Zabelina DL. Parametric Cortical Representations of Complexity and Preference for Artistic and Computer-Generated Fractal Patterns Revealed by Single-Trial EEG Power Spectral Analysis. Neuroimage 2021; 236:118092. [PMID: 33895307 PMCID: PMC8287964 DOI: 10.1016/j.neuroimage.2021.118092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 11/29/2022] Open
Abstract
Fractals are self-similar patterns that repeat at different scales, the complexity of which are expressed as a fractional Euclidean dimension D between 0 (a point) and 2 (a filled plane). The drip paintings of American painter Jackson Pollock (JP) are fractal in nature, and Pollock's most illustrious works are of the high-D (~1.7) category. This would imply that people prefer more complex fractal patterns, but some research has instead suggested people prefer lower-D fractals. Furthermore, research has suggested that parietal and frontal brain activity tracks the complexity of fractal patterns, but previous research has artificially binned fractals depending on fractal dimension, rather than treating fractal dimension as a parametrically varying value. We used white layers extracted from JP artwork as stimuli, and constructed statistically matched 2-dimensional random Cantor sets as control stimuli. We recorded the electroencephalogram (EEG) while participants viewed the JP and matched random Cantor fractal patterns. Participants then rated their subjective preference for each pattern. We used a single-trial analysis to construct within-subject models relating subjective preference to fractal dimension D, as well as relating D and subjective preference to single-trial EEG power spectra. Results indicated that participants preferred higher-D images for both JP and Cantor stimuli. Power spectral analysis showed that, for artistic fractal images, parietal alpha and beta power parametrically tracked complexity of fractal patterns, while for matched mathematical fractals, parietal power tracked complexity of patterns over a range of frequencies, but most prominently in alpha band. Furthermore, parietal alpha power parametrically tracked aesthetic preference for both artistic and matched Cantor patterns. Overall, our results suggest that perception of complexity for artistic and computer-generated fractal images is reflected in parietal-occipital alpha and beta activity, and neural substrates of preference for complex stimuli are reflected in parietal alpha band activity.
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Affiliation(s)
- Eric Rawls
- Department of Psychiatry and Behavioral Sciences, University of Minnesota Health.
| | - Rebecca White
- Department of Psychology, University of New Hampshire
| | - Stephanie Kane
- Department of Psychological Sciences, University of Arkansas
| | - Carl E Stevens
- Department of Psychological Sciences, University of Arkansas
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Tosun S, Karataslioglu E, Tulgar MM, Derindag G. Retrospective fractal analyses of one-year follow-up data obtained after single-visit nonsurgical endodontic retreatment on periapical radiographs. Clin Oral Investig 2021; 25:6465-6472. [PMID: 34302217 DOI: 10.1007/s00784-021-04079-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 07/12/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVES The aim of retrospective study was to evaluate the changes to the periapical bone sites after non-surgical endodontic retreatment by using fractal analysis on periapical radiographs. MATERIALS AND METHODS Thirty patients whose teeth had periapical lesions and underwent primary endodontic treatment were selected for nonsurgical single-visit endodontic retreatment. Two radiographs were taken, the first immediately after retreatment and the second at the 1-year follow-up. An identical region of interest close to the infected root apex was selected from each radiograph. FD was measured using the box-counting method. Periapical status was evaluated using the periapical index (PAI). Treatment outcomes were categorized into healed (PAI < 3), or not healed (PAI ≥ 3) based on radiographic criteria. RESULTS The mean FD value significantly increased at the 1-year follow-up compared to baseline. No significant sex biases were apparent. According to the PAI, retreatment after 1 year resulted in a 63.3% healed. CONCLUSION The extent of periapical trabecular bone evident radiographically increased, as revealed by FD data, 1 year after endodontic retreatment. Clinical relevance The use of fractal analysis as a quantitative method to evaluate changes in periapical trabecular bone (such as healing and inflammation) after endodontic retreatment can be an important marker in determining the prognosis of endodontic retreatment.
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Affiliation(s)
- Samet Tosun
- Department of Endodontics, Faculty of Dentistry, Pamukkale University, 20160, Pamukkale, Denizli, Turkey.
| | - Emrah Karataslioglu
- Department of Endodontics, Faculty of Dentistry, Katip Çelebi University, 35300, İzmir, Turkey
| | - Mustafa Mert Tulgar
- Department of Endodontics, Faculty of Dentistry, Katip Çelebi University, 35300, İzmir, Turkey
| | - Gözde Derindag
- Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Pamukkale University, 20160, Denizli, Turkey
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Luppi AI, Craig MM, Coppola P, Peattie ARD, Finoia P, Williams GB, Allanson J, Pickard JD, Menon DK, Stamatakis EA. Preserved fractal character of structural brain networks is associated with covert consciousness after severe brain injury. Neuroimage Clin 2021; 30:102682. [PMID: 34215152 PMCID: PMC8102619 DOI: 10.1016/j.nicl.2021.102682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/30/2021] [Accepted: 04/18/2021] [Indexed: 12/24/2022]
Abstract
We study structural brain networks in patients with disorders of consciousness (DOC) Structural brain networks are less fractal (self-similar) in patients than controls. Preserved fractal dimension is associated with covert consciousness in DOC patients.
Self-similarity is ubiquitous throughout natural phenomena, including the human brain. Recent evidence indicates that fractal dimension of functional brain networks, a measure of self-similarity, is diminished in patients diagnosed with disorders of consciousness arising from severe brain injury. Here, we set out to investigate whether loss of self-similarity is observed in the structural connectome of patients with disorders of consciousness. Using diffusion MRI tractography from N = 11 patients in a minimally conscious state (MCS), N = 10 patients diagnosed with unresponsive wakefulness syndrome (UWS), and N = 20 healthy controls, we show that fractal dimension of structural brain networks is diminished in DOC patients. Remarkably, we also show that fractal dimension of structural brain networks is preserved in patients who exhibit evidence of covert consciousness by performing mental imagery tasks during functional MRI scanning. These results demonstrate that differences in fractal dimension of structural brain networks are quantitatively associated with chronic loss of consciousness induced by severe brain injury, highlighting the close connection between structural organisation of the human brain and its ability to support cognitive function.
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Affiliation(s)
- Andrea I Luppi
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom.
| | - Michael M Craig
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom
| | - Peter Coppola
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom
| | - Alexander R D Peattie
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom
| | - Paola Finoia
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Division of Neurosurgery, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom
| | - Guy B Williams
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Wolfson Brain Imaging Centre, University of Cambridge, Cambridge Biomedical Campus (Box 65), Cambridge CB2 0QQ, United Kingdom
| | - Judith Allanson
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Department of Neurosciences, Cambridge University Hospitals NHS Foundation, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom
| | - John D Pickard
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Division of Neurosurgery, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Wolfson Brain Imaging Centre, University of Cambridge, Cambridge Biomedical Campus (Box 65), Cambridge CB2 0QQ, United Kingdom
| | - David K Menon
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Wolfson Brain Imaging Centre, University of Cambridge, Cambridge Biomedical Campus (Box 65), Cambridge CB2 0QQ, United Kingdom
| | - Emmanuel A Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, CB2 0SP, Cambridge, United Kingdom
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Barochiner J. [Complexity theory and the hypertensive patient]. Semergen 2021:S1138-3593(21)00060-5. [PMID: 33836976 DOI: 10.1016/j.semerg.2020.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 11/21/2022]
Abstract
Hypertension is the main cause of death worldwide and the approach that the Family Physician makes of hypertensive patients, given his or her key role as a gateway to the health system, is a crucial determinant in their evolution. On the other hand, Complexity theory contributes to the understanding on how systems grow, adapt and evolve. The hypertensive patient, given his character of biological and social being, can be understood and approached as a complex system. Understanding the characteristics of these systems contributes to considering the patient from another perspective, more satisfactory both for himself and for the professional who assists him. This review analyzes the characteristics of the complex system «hypertensive patient» and the tools that allow us to account for and interact with this complexity. An approach from multiple perspectives, migrating from the classic reductionist models to others that take into account the dynamic interrelationships that are at stake, would be a useful strategy for the Family Physician in the challenge of achieving adequate control of blood pressure in his or her patients.
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Kelty-Stephen DG, Lee IC, Carver NS, Newell KM, Mangalam M. Multi fractal roots of suprapostural dexterity. Hum Mov Sci 2021; 76:102771. [PMID: 33601240 DOI: 10.1016/j.humov.2021.102771] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 12/14/2022]
Abstract
Visually guided postural control emerges in response to task constraints. Task constraints generate physiological fluctuations that foster the exploration of available sensory information at many scales. Temporally correlated fluctuations quantified using fractal and multifractal metrics have been shown to carry perceptual information across the body. The risk of temporally correlated fluctuations is that stable sway appears to depend on a healthy balance of standard deviation (SD): too much or too little SD entails destabilization of posture. This study presses on the visual guidance of posture by prompting participants to quietly stand and fixate at distances within, less than, and beyond comfortable viewing distance. Manipulations of the visual precision demands associated with fixating nearer and farther than comfortable viewing distance reveals an adaptive relationship between SD and temporal correlations in postural fluctuations. Changing the viewing distance of the fixation target shows that increases in temporal correlations and SD predict subsequent reductions in each other. These findings indicate that the balance of SD within stable bounds may depend on a tendency for temporal correlations to self-correct across time. Notably, these relationships became stronger with greater distance from the most comfortable viewing and reaching distance, suggesting that this self-correcting relationship allows the visual layout to press the postural system into a poise for engaging with objects and events. Incorporating multifractal analysis showed that all effects attributable to monofractal evidence were better attributed to multifractal evidence of nonlinear interactions across scales. These results offer a glimpse of how current nonlinear dynamical models of self-correction may play out in biological goal-oriented behavior. We interpret these findings as part of the growing evidence that multifractal nonlinearity is a modeling strategy that resonates strongly with ecological-psychological approaches to perception and action.
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Affiliation(s)
| | - I Chieh Lee
- UNC-NC State Joint Department of Biomedical Engineering, UNC-Chapel Hill, Chapel Hill, NC 27514, USA
| | - Nicole S Carver
- Department of Psychology, University of Cincinnati, Cincinnati, OH, United States
| | - Karl M Newell
- Department of Kinesiology, University of Georgia, Athens, GA 30602, USA
| | - Madhur Mangalam
- Department of Physical Therapy, Movement and Rehabilitation Sciences, Northeastern University, Boston, MA 02115, USA.
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Dosso JA, Anderson NC, Wahn B, Choi GSJ, Kingstone A. Social modulation of on-screen looking behaviour. Vision Res 2021; 182:1-8. [PMID: 33550023 DOI: 10.1016/j.visres.2020.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 12/18/2020] [Accepted: 12/28/2020] [Indexed: 11/16/2022]
Abstract
While passive social information (e.g. pictures of people) routinely draws one's eyes, our willingness to look at live others is more nuanced. People tend not to stare at strangers and will modify their gaze behaviour to avoid sending undesirable social signals; yet they often continue to monitor others covertly "out of the corner of their eyes." What this means for looks that are being made near to live others is unknown. Will the eyes be drawn towards the other person, or pushed away? We evaluate changes in two elements of gaze control: image-independent principles guiding how people look (e.g. biases to make eye movements along the cardinal directions) and image-dependent principles guiding what people look at (e.g. a preference for meaningful content within a scene). Participants were asked to freely view semantically unstructured (fractals) and semantically structured (rotated landscape) images, half of which were located in the space near to a live other. We found that eye movements were horizontally displaced away from a visible other starting at 1032 ms after stimulus onset when fractals but not landscapes were viewed. We suggest that the avoidance of looking towards live others extends to the near space around them, at least in the absence of semantically meaningful gaze targets.
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Affiliation(s)
- Jill A Dosso
- Department of Psychology, University of British Columbia, Canada.
| | | | - Basil Wahn
- Department of Psychology, University of British Columbia, Canada
| | - Gini S J Choi
- Department of Psychology, University of British Columbia, Canada
| | - Alan Kingstone
- Department of Psychology, University of British Columbia, Canada
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Rao B, Pang H, Fan F, Zhang J, Xu P, Qiu S, Wu X, Lu X, Zhu J, Wang G, Su J. Pore-scale model and dewatering performance of municipal sludge by ultrahigh pressurized electro-dewatering with constant voltage gradient. Water Res 2021; 189:116611. [PMID: 33221587 DOI: 10.1016/j.watres.2020.116611] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 06/11/2023]
Abstract
The disposal of huge municipal sludge with high moisture content has led to numerous energy consumption and brought extensive concerns in the world. In this paper, three dewatering modes, ultrahigh-pressure mechanical dewatering mode (UMDW), pressurized electro-dewatering (PEDW) with constant voltage mode (U-PEDW) and constant voltage gradient mode (G-PEDW) were performed on a self-designed pressurized electro-dewatering apparatus for municipal sludge. The pore structures and moisture distributions were detected by low-field nuclear magnetic resonance technology. Meanwhile, the moisture distributions and quantitative bound strength were analyzed by the thermogravimetric differential scanning calorimetry test. Moreover, a pore-scale electro-osmosis model was accordingly developed based on the fractal characteristics of pore size distribution. Finally, the effect of dewatering modes and operating parameters on moisture content and energy consumption were examined in detail. The results indicate that the pore-scale electro-osmosis model show good consistency with experimental data. The electric field can drive the middle-layers-water to overcome the capillary pressure, and make G-PEDW removing more water than UMDW. The moisture content of dewatered municipal sludge by G-PEDW and U-PEDW reaches to 28.41% and 27.33%, respectively. Furthermore, the energy consumption of G-PEDW is 189.62Wh/kg.H2O, it is much lower than that of U-PEDW. Therefore, the G-PEDW mode with low moisture content and less energy consumption indicates best dewatering performance compared with UMDW and U-PEDW modes. The present work is helpful to understand the dewatering mechanisms of G-PEDW and provides useful guidelines for G-PEDW dewatering technology.
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Affiliation(s)
- Binqi Rao
- College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou, 310018, PR China.
| | - Hongru Pang
- College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou, 310018, PR China
| | - Feibiao Fan
- Zhejiang Chunhui Environmental Protection Energy Co., Ltd, Shaoxing, 312300, PR China
| | - Jicheng Zhang
- College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou, 310018, PR China
| | - Peng Xu
- College of Science, China Jiliang University, Hangzhou, 310018, PR China.
| | - Shuxia Qiu
- College of Science, China Jiliang University, Hangzhou, 310018, PR China
| | - Xu Wu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China
| | - Xilong Lu
- College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou, 310018, PR China
| | - Jianwei Zhu
- School of Mechatronics and Automobile Engineering, Huzhou Vocational & Technical College, Huzhou 313000, PR China
| | - Gongqin Wang
- College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou, 310018, PR China
| | - Jiangge Su
- College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou, 310018, PR China
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Pugno MC, Misseroni D, Pugno NM. Air-encapsulating elastic mechanism of submerged Taraxacum blowballs. Mater Today Bio 2021; 9:100095. [PMID: 33718857 DOI: 10.1016/j.mtbio.2021.100095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/02/2021] [Accepted: 01/08/2021] [Indexed: 11/25/2022] Open
Abstract
In this article, we report the observation of an air-encapsulating elastic mechanism of Dandelion spherical seed heads, namely blowballs, when submerged underwater. This peculiarity seems to be fortuitous since Taraxacum is living outside water; nevertheless, it could become beneficial for a better survival under critical conditions, e.g. of temporary flooding. The scaling of the volume of the air entrapped suggests its fractal nature with a dimension of 2.782 and a fractal air volume fraction of 4.82 × 10−2 m0.218, resulting in nominal air volume fractions in the range of 14–23%. This aspect is essential for the optimal design of bioinspired materials made up of Dandelion-like components. The miniaturization of such components leads to an increase in the efficiency of the air encapsulation up to the threshold (efficiency = 1) achieved for an optimal critical size. Thus, the optimal design is accomplished using small elements, with the optimal size, rather than using larger elements in a lower number. The described phenomenon, interesting per se, also brings bioinspired insights toward new related technological solutions for underwater air-trapping and air-bubbles transportation, e.g. the body surface of a man could allow an apnea (air consumption of 5–10 l/min) of about 10 min if it is covered by a material made up of a periodic repetition of Dandelion components of diameter ≅18 μm and having a total thickness of about 3–6 cm.
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Jacobson N, Berleman-Paul Q, Mangalam M, Kelty-Stephen DG, Ralston C. Multi fractality in postural sway supports quiet eye training in aiming tasks: A study of golf putting. Hum Mov Sci 2021; 76:102752. [PMID: 33468324 DOI: 10.1016/j.humov.2020.102752] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/19/2020] [Accepted: 12/22/2020] [Indexed: 01/13/2023]
Abstract
The 'quiet eye' (QE) approach to visually-guided aiming behavior invests fully in perceptual information's potential to organize coordinated action. Sports psychologists refer to QE as the stillness of the eyes during aiming tasks and increasingly into self- and externally-paced tasks. Amidst the 'noisy' fluctuations of the athlete's body, quiet eyes might leave fewer saccadic interruptions to the coupling between postural sway and optic flow. Postural sway exhibits fluctuations whose multifractal structure serves as a robust predictor of visual and haptic perceptual responses. Postural sway generates optic flow centered on an individual's eye height. We predicted that perturbing the eye height by attaching wooden blocks below the feet would perturb the putting more so in QE-trained participants than participants trained technically. We also predicted that QE's efficacy and responses to perturbation would depend on multifractality in postural sway. Specifically, we predicted that less multifractality would predict more adaptive responses to the perturbation and higher putting accuracy. Results showed that lower multifractality led to more accurate putts, and the perturbation of eye height led to less accurate putts, particularly for QE-trained participants. Models of radial error (i.e., the distance between the ball's final position and the hole) indicated that lower estimates of multifractality due to nonlinearity coincided with a more adaptive response to the perturbation. These results suggest that reduced multifractality may act in a context-sensitive manner to restrain motoric degrees of freedom to achieve the task goal.
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Affiliation(s)
- Noah Jacobson
- Department of Psychology, Grinnell College, Grinnell, IA 50112, USA
| | | | - Madhur Mangalam
- Department of Physical Therapy, Movement and Rehabilitation Sciences, Northeastern University, Boston, MA 02115, USA
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Sawa K, Igamberdiev AU. The emergence of a fractal structure of formal logic via the spatiotemporal reflexive self-identification. Biosystems 2021; 202:104342. [PMID: 33417979 DOI: 10.1016/j.biosystems.2020.104342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/27/2020] [Accepted: 12/28/2020] [Indexed: 12/12/2022]
Abstract
In this paper, we aim to analyze the structure of formal logic in relation to its emergence as a universal tool for understanding and description of reality. There are some extended variations of logic that treat time and/or space (e.g. temporal logic), however in general, formal logic is regarded as universal. This universality makes formal logic neither spatial nor temporal. Nevertheless, the emergence of formal logic takes place in time and space and its operation is characterized by the simultaneous temporal and spatial features. We realize these aspects of formal logic along the line of the previously developed model of the Double Homunculus (Sawa K., Igamberdiev A.U., 2016, BioSystems 144, 1-7) which can be seen as an emergence of logic. A diagrammatic representation of this concept reveals fractal structures. At the same time, we present actual logical connectives on these fractal figures with the transformations over time and space. This can provide the basis for understanding the relationships between time, space, and logic.
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Affiliation(s)
- Koji Sawa
- Center for Learning Support and Faculty Development, Doshisha University, Kyoto, 610-0394, Japan.
| | - Abir U Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
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Carrasco AC, Silva MF, Guenka LC, Bueno MJO, Dela Bela LF, Torres RS, Moura FA, Cardoso JR. Test-retest reliability of multiscale fractal dimension measurements of plantar pressure maps during dynamic tasks. J Biomech 2020; 113:110103. [PMID: 33142208 DOI: 10.1016/j.jbiomech.2020.110103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/31/2020] [Accepted: 10/17/2020] [Indexed: 11/17/2022]
Abstract
The tools used to evaluate foot types are divergent since they adopt classic linear analyzes, based on anthropometric or image measurements, which do not dynamically contemplate the variability of foot shape. The use of newer techniques such as multiscale fractal dimension (MFD) may be a key to this type of problem. However, for these measures to be used safely and consistently, it is essential to evaluate their reliability. The aim of this study was to evaluate the test-retest reliability of MFD measurements of adult plantar pressure maps during gait, as well as the standard error of measurement (SEM), and minimal detectable change (MDC90). Seventy-two subjects were included in the test-retest, with a one week interval. The plantar pressure maps were constructed using a pressure platform. The data were processed in a routine for extracting the MFD curve measurements (maximum and integral values). The Intraclass Correlation Coefficient results (ICC3,k) were excellent for both measurements (maximum value 0.96, 95% confidence interval [0.93-0.97], and integral 0.95 [0.92-0.97]) with low SEM and MDC90 values below 10% of the mean. The application of MFD to the plantar pressure data generated by the pressure platform is reliable and could allow exploration of the complexity of foot shapes, enabling their classification.
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Affiliation(s)
- Aline C Carrasco
- Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil
| | - Mariana F Silva
- Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil
| | - Leandro C Guenka
- Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil
| | - Murilo J O Bueno
- Laboratory of Applied Biomechanics, Universidade Estadual de Londrina, Londrina, PR, Brazil
| | - Laís F Dela Bela
- Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil; Positivo University, Curitiba, PR, Brazil
| | | | - Felipe A Moura
- Laboratory of Applied Biomechanics, Universidade Estadual de Londrina, Londrina, PR, Brazil
| | - Jefferson R Cardoso
- Laboratory of Biomechanics and Clinical Epidemiology, PAIFIT Research Group, Universidade Estadual de Londrina, Londrina, PR, Brazil.
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Ilarraza-Lomelí H, Rius-Suárez MD. Complexus cordis. Arch Cardiol Mex 2020; 91:327-336. [PMID: 33232968 PMCID: PMC8351662 DOI: 10.24875/acm.200000391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 07/18/2020] [Indexed: 11/17/2022] Open
Abstract
The science-based study of the heart has allowed us to know its structure and function deeply, through the fragmentation and analysis of its parts, following the guidelines that so many achievements have given to us. However, at the time of reassembling those analyzed fragments, we realize that something is missing; the simply sum of the parts is not equal to everything. Thus, for decades, numerous scientists have studied novel strategies that allow us understanding, every natural phenomena from a more inclusive, open and integrative models, which closely address to interactions rather than components. In this way, we can observe how, the behavior of many variables usually transgress the conventional plane and moves towards non-linearity and fractality, making a complex tissue that will maintain its structure while thermodynamically viable. Thus, this document shows the way how, the non-linear study of complex cardiovascular dynamics, begins to give us answers to many questions that the clinical cardiologist poses every day.
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Affiliation(s)
- Hermes Ilarraza-Lomelí
- Servicio de Rehabilitación Cardiaca y Medicina Física, Instituto Nacional de Cardiología Ignacio Chávez, Ciudad de México, México
| | - María D. Rius-Suárez
- Servicio de Rehabilitación Cardiaca y Medicina Física, Instituto Nacional de Cardiología Ignacio Chávez, Ciudad de México, México
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Guarnieri R, Miccoli G, Di Nardo D, D'Angelo M, Morese A, Seracchiani M, Testarelli L. Effect of a laser-ablated micron-scale modification of dental implant collar surface on changes in the vertical and fractal dimensions of peri-implant trabecular bone. Clin Ter 2020; 171:e385-e392. [PMID: 32901779 DOI: 10.7417/ct.2020.2245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Marginal bone loss (MBL) represents an important indicator of peri-implant health and the measure of its level is considered a determining factor in the evaluation of the quality of survival. Aim of this study is to compare radiographic changes in the fractal and mesial/distal vertical dimensions of peri-implant trabecular bone of dental implants with a laser-ablated micron-scale modication (LAM) of collar surface after a 5-year follow-up period. MATERIALS AND METHODS Thirty-four implants with LAM of collar surface (test group = TG) and 31 implants without LAM of collar surface (control group = CG) were placed in 45 non-smoking, periodontally healthy patients. Fractal and vertical dimensions of peri-implant trabecular bone were measured by comparing radiographs taken immediately after prosthesis delivery with those taken 3 years and 5 years after functional loading. RESULT At the end of the 5-year follow-up, the MBL in the TG was 0.87±0.21 and 0.75±0.25 mm at the mesial and distal aspects, respectively, while a MBL of 2.05±0.25 mm at the mesial aspect and 2.01±0.34 mm at the distal site was recorded in the CG. A statistically significant difference was noted. In the TG the mean fractal dimension before loading was 1.4213±0.0525. It increased significantly to 1.4329±0.0479 at 3 years after loading and remained almost stable at 5 years after loading (1.4327±0.0291). In the CG the mean fractal dimension before loading was 1.4119±0.0414. It increased significantly to 1.4282±0.0324 at 3 years after loading and decreased significantly to 1.4111±0.0624 at 5 years after loading. At the end of the follow-up, differences between both study groups were statistically significant. CONCLUSION The increased fractal dimension and the reduced MBL around TG implants after 5 years of functional loading indicates a positive effect of a laser-ablated micron-scale modication of collar surface on peri-implant trabecular bone remodeling.
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Affiliation(s)
- R Guarnieri
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, Italy
| | - G Miccoli
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, Italy
| | - D Di Nardo
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, Italy
| | - M D'Angelo
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, Italy
| | - A Morese
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, Italy
| | - M Seracchiani
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, Italy
| | - L Testarelli
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, Italy
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Shrestha S, Kulandaivelu J, Rebosura MJR, Yuan Z, Sharma K. Revealing the variations in physicochemical, morphological, fractal, and rheological properties of digestate during the mesophilic anaerobic digestion of iron-rich waste activated sludge. Chemosphere 2020; 254:126811. [PMID: 32334260 DOI: 10.1016/j.chemosphere.2020.126811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 04/05/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
Dosing of iron (Fe)-salts in sewers to control odour and corrosion problems have proven to be effective on phosphate and sulfide removal in downstream treatment units. However, the interaction of Fe with sludge may impact the sludge properties during wastewater treatment and sludge digestion. Herein, we investigated the downstream impacts of sewer-dosed Fe-salt on key digestate properties including digestate dewaterability. For this, Fe-salt was dosed to a sewer reactor and resultant iron-rich waste activated sludge (Fe-WAS) was digested in an anaerobic digester (AD) in the experimental line of integrated laboratory system running in parallel to a control system. Iron containing and non-iron containing digestates were sourced from the respective AD reactors of experimental and control lines. Results showed improved dewaterability in iron containing digestate than non-iron containing digestate, which was attributed to the variations in key digestate properties. Compared to non-iron containing digestate, iron containing digestate exhibited the decreased contents of bound water, soluble extracellular polymeric substances (S-EPS), protein, polysaccharide, and monovalent-to-divalent (M+/D++) cations ratio. Likewise, we observed the increased mean particle size (Dv50) for iron containing digestate than the non-iron containing digestate, but fractal dimension (Df) values were comparable. Besides, iron containing digestate exhibited a reduced degree of thixotropy, relative sludge network strength, viscosity, yield stress, flow stress, and storage/loss/complex (G'/G''/G∗) moduli but increased creep compliance and shear strain (%) than non-iron containing digestate. The combined synergistic effects of such favorable changes amongst the key properties of iron containing digestate, might have been responsible for improving it's dewaterability.
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Affiliation(s)
- Sohan Shrestha
- Advanced Water Management Centre, The School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia
| | - Jagadeeshkumar Kulandaivelu
- Advanced Water Management Centre, The School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia
| | - Mario Jr Robles Rebosura
- Advanced Water Management Centre, The School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia
| | - Keshab Sharma
- Advanced Water Management Centre, The School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia.
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Desmet DM, Westbrook AD, Grabiner MD. Treadmill-belt width, but not feedback from the lower visual field, influences the noise characteristics of step width time series. J Biomech 2020; 109:109943. [PMID: 32807305 DOI: 10.1016/j.jbiomech.2020.109943] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 06/18/2020] [Accepted: 07/02/2020] [Indexed: 10/23/2022]
Abstract
Step kinematic variability, which has been associated with gait-related fall risk, is thought to be attributed to neuromotor noise. Altered neuromotor control of step kinematics would be expected to manifest as changes in the noise-related characteristics of the step kinematic time series. This study determined the effects of eliminating feedback from the lower visual field and reducing treadmill-belt width on the noise characteristics of step width time series and statistical measures of step width variability during treadmill walking. We hypothesized that eliminating feedback from the lower visual field and reducing treadmill-belt width would both alter the noise characteristics of step width time series, reflected by decreased fractal scaling, and increase statistical measures of step width variability. Eighteen young adults performed four randomly ordered walking trials during which we manipulated visual feedback from the lower visual field (normal and obstructed) and treadmill-belt width (wide and narrow). Reducing treadmill-belt width, but not eliminating feedback from the lower visual field, significantly reduced the fractal scaling of step width time series, indicating a shift towards white, uncorrelated noise. These results suggest that accounting for the influence of treadmill-belt width on step width time series may be an important consideration in both laboratory and clinical settings. Further work is needed to clarify the effects of vision on measures of step width, identify the mechanism(s) underlying the observed shift towards white, uncorrelated noise associated with reduced treadmill-belt width, and to assess the potential relationship between the noise characteristics of step width time series and fall risk.
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Affiliation(s)
- David M Desmet
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, United States.
| | - Aaron D Westbrook
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Mark D Grabiner
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, United States
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Varley TF, Carhart-Harris R, Roseman L, Menon DK, Stamatakis EA. Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains. Neuroimage 2020; 220:117049. [PMID: 32619708 DOI: 10.1016/j.neuroimage.2020.117049] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 05/12/2020] [Accepted: 06/09/2020] [Indexed: 12/19/2022] Open
Abstract
Psychedelic drugs, such as psilocybin and LSD, represent unique tools for researchers investigating the neural origins of consciousness. Currently, the most compelling theories of how psychedelics exert their effects is by increasing the complexity of brain activity and moving the system towards a critical point between order and disorder, creating more dynamic and complex patterns of neural activity. While the concept of criticality is of central importance to this theory, few of the published studies on psychedelics investigate it directly, testing instead related measures such as algorithmic complexity or Shannon entropy. We propose using the fractal dimension of functional activity in the brain as a measure of complexity since findings from physics suggest that as a system organizes towards criticality, it tends to take on a fractal structure. We tested two different measures of fractal dimension, one spatial and one temporal, using fMRI data from volunteers under the influence of both LSD and psilocybin. The first was the fractal dimension of cortical functional connectivity networks and the second was the fractal dimension of BOLD time-series. In addition to the fractal measures, we used a well-established, non-fractal measure of signal complexity and show that they behave similarly. We were able to show that both psychedelic drugs significantly increased the fractal dimension of functional connectivity networks, and that LSD significantly increased the fractal dimension of BOLD signals, with psilocybin showing a non-significant trend in the same direction. With both LSD and psilocybin, we were able to localize changes in the fractal dimension of BOLD signals to brain areas assigned to the dorsal-attenion network. These results show that psychedelic drugs increase the fractal dimension of activity in the brain and we see this as an indicator that the changes in consciousness triggered by psychedelics are associated with evolution towards a critical zone.
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Affiliation(s)
- Thomas F Varley
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, UK; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, UK; Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, USA.
| | - Robin Carhart-Harris
- Centre for Neuropsychopharmacology, Department of Medicine, Imperial College London, London, UK
| | - Leor Roseman
- Centre for Neuropsychopharmacology, Department of Medicine, Imperial College London, London, UK; Computational, Cognitive and Clinical Neuroscience Laboratory, Department of Medicine, Imperial College London, London, UK
| | - David K Menon
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, UK
| | - Emmanuel A Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, UK; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, UK
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Hart MG, Romero-Garcia R, Price SJ, Suckling J. Global Effects of Focal Brain Tumors on Functional Complexity and Network Robustness: A Prospective Cohort Study. Neurosurgery 2020; 84:1201-1213. [PMID: 30137556 PMCID: PMC6520100 DOI: 10.1093/neuros/nyy378] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 07/19/2018] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Neurosurgical management of brain tumors has entered a paradigm of supramarginal resections that demands thorough understanding of peritumoral functional effects. Historically, the effects of tumors have been believed to be local, and long-range effects have not been considered. OBJECTIVE To test the hypothesis that tumors affect the brain globally, producing long-range gradients in cortical function. METHODS Resting-state functional magnetic resonance imaging (fMRI) data were acquired from 11 participants with glioblastoma and split into discovery and validation datasets in a single-center prospective cohort study. Fractal complexity was computed with a wavelet-based estimator of the Hurst exponent. Distance-related effects of the tumors were tested with a tumor mask-dilation technique and parcellation of the underlying Hurst maps. RESULTS Fractal complexity demonstrates a penumbra of suppression in the peritumoral region. At a global level, as distance from the tumor increases, this initial suppression is balanced by a subsequent overactivity before finally normalizing. These effects were best fit by a quadratic model and were consistent across different network construction pipelines. The Hurst exponent was correlated with graph theory measures of centrality including network robustness, but graph theory measures did not demonstrate distance-dependent effects. CONCLUSION This work provides evidence supporting the theory that focal brain tumors produce long-range gradients in function. Consequently, the effects of focal lesions need to be interpreted in terms of the global changes on functional complexity and network architecture rather than purely in terms of functional localization. Determining whether peritumoral changes represent potential plasticity may facilitate extended resection of tumors without functional cost.
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Affiliation(s)
- Michael G Hart
- Brain Mapping Unit, Department of Psychiatry, Sir William Hardy Building, University of Cambridge, Cambridge, United Kingdom.,Academic Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Rafael Romero-Garcia
- Brain Mapping Unit, Department of Psychiatry, Sir William Hardy Building, University of Cambridge, Cambridge, United Kingdom.,Academic Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Stephen J Price
- Academic Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - John Suckling
- Brain Mapping Unit, Department of Psychiatry, Herchel Smith Building for Brain and Mind Sciences, University of Cambridge, Cambridge, United Kingdom
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Hart MG, Romero-Garcia R, Price SJ, Santarius T, Suckling J. Connections, Tracts, Fractals, and the Rest: A Working Guide to Network and Connectivity Studies in Neurosurgery. World Neurosurg 2020; 140:389-400. [PMID: 32247795 DOI: 10.1016/j.wneu.2020.03.116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 12/26/2022]
Abstract
Brain mapping and connectomics can probe networks that span the entire brain, producing a diverse range of outputs for probing specific clinically relevant questions. The potential for understanding the effect of focal lesions on brain function, cognition, and plasticity abounds, any one of which would likely yield more effective and safer neurosurgical strategies. However, the possibilities of advanced magnetic resonance imaging and connectomics have been somewhat underused in neurosurgery, arising from actual or perceived difficulties in either application or analysis. The present review builds on previous work describing the theoretical attractions of connectomics to deliberate on the practical details of performing high-quality connectomics studies in neurosurgery. First, the data and methods involved in deriving connectomics models will be considered, specifically for the purpose of determining the nature of inferences that can be made subsequently. Next, a selection of key analysis methods will be explored using practical examples that illustrate their effective implementation and the insights that can be gleaned. The principles of study design will be introduced, including analysis tips and methods for making efficient use of available resources. Finally, a review of the best research practices for neuroimaging studies will be discussed, including principles of open access data sharing, study preregistration, and methods for improving replicability. Ultimately, we hope readers will be better placed to appraise the current connectomics studies in neurosurgery and empowered to develop their own high-quality studies, both of which are key steps in realizing the true potential of connectomics and advanced neuroimaging analyses in general.
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Pérez-López S, Fuster JM, Candelas P, Rubio C. Fractal lenses based on Cantor binary sequences for ultrasound focusing applications. Ultrasonics 2019; 99:105967. [PMID: 31374429 DOI: 10.1016/j.ultras.2019.105967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 07/02/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
In this work, we demonstrate the application of Cantor fractal lenses in acoustics. The Cantor Zone Plate (CZP), previously introduced in optics, is designed from a conventional Fresnel Zone Plate (FZP) using a binary sequence governed by the distribution of a generalized Cantor set. The CZP maintains its main focus at the same focal distance than its associated FZP, providing a softer multi-foci focusing profile which is very useful in certain ultrasound therapeutic applications. Experimental measurements are in good agreement with the theoretical model, demonstrating that CZPs are suitable for the ultrasound field.
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Affiliation(s)
- Sergio Pérez-López
- Centro de Tecnologías Físicas, Universitat Politècnica de València, 46022, Spain.
| | - José Miguel Fuster
- Departamento de Comunicaciones, Universitat Politècnica de València, 46022, Spain
| | - Pilar Candelas
- Centro de Tecnologías Físicas, Universitat Politècnica de València, 46022, Spain
| | - Constanza Rubio
- Centro de Tecnologías Físicas, Universitat Politècnica de València, 46022, Spain
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Hattori Y, Kimura Y, Yoshioka T, Kitamura M. Data on optical microscopy and vibrational modes in Diphenyl Dinaphthothienothiophene thin films. Data Brief 2019; 26:104522. [PMID: 31667285 PMCID: PMC6811884 DOI: 10.1016/j.dib.2019.104522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/06/2019] [Indexed: 12/03/2022] Open
Abstract
The thin-films of 2,9-diphenyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DPh-DNTT) prepared by vacuum deposition was observed by the optical microsope. By applying the dark-field mode in observation and/or image processing after imaging appropriately, morphological structure with a resolution of a few nanometers height was visualized easily and quickly. The technique can be used in a similar to atomic force microscopy, which is commonly used for imaging surface morphology. Moreover, the vibrational modes of a DPh-DNTT molecule calculated by quantum chemistry program is described as well as the comparison of the experimental Raman spectra for identification. The presented data are produced as part of the main work entitled “The Growth Mechanism and Characterization of Few-layer Diphenyl Dinaphthothienothiophene Films Prepared by Vacuum Deposition” (Hattori et al., 2019).
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Affiliation(s)
- Yoshiaki Hattori
- Department of Electrical and Electronic Engineering, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Yoshinari Kimura
- Department of Electrical and Electronic Engineering, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Takumi Yoshioka
- Department of Electrical and Electronic Engineering, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Masatoshi Kitamura
- Department of Electrical and Electronic Engineering, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
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Gilfriche P, Arsac LM, Blons E, Deschodt-Arsac V. Fractal properties and short-term correlations in motor control in cycling: influence of a cognitive challenge. Hum Mov Sci 2019; 67:102518. [PMID: 31542675 DOI: 10.1016/j.humov.2019.102518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 09/05/2019] [Accepted: 09/05/2019] [Indexed: 10/26/2022]
Abstract
Fluctuations in cyclic tasks periods is a known characteristic of human motor control. Specifically, long-range fractal fluctuations have been evidenced in the temporal structure of these variations in human locomotion and thought to be the outcome of a multicomponent physiologic system in which control is distributed across intricate cortical, spinal and neuromuscular regulation loops. Combined with long-range correlation analyses, short-range autocorrelations have proven their use to describe control distribution across central and motor components. We used relevant tools to characterize long- and short-range correlations in revolution time series during cycling on an ergometer in 19 healthy young adults. We evaluated the impact of introducing a cognitive task (PASAT) to assess the role of central structures in control organization. Autocorrelation function and detrending fluctuation analysis (DFA) demonstrated the presence of fractal scaling. PSD in the short range revealed a singular behavior which cannot be explained by the usual models of even-based and emergent timing. The main outcomes are that (1) timing in cycling is a fractal process, (2) this long-range fractal behavior increases in persistence with dual-task condition, which has not been previously observed, (3) short-range behavior is highly persistent and unaffected by dual-task. Relying on the inertia of the oscillator may be a way to distribute more control to the periphery, thereby allocating less resources to central process and better managing additional cognitive demands. This original behavior in cycling may explain the high short-range persistence unaffected by dual-task, and the increase in long-range persistence with dual-task.
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Affiliation(s)
- Pierre Gilfriche
- CATIE - Centre Aquitain des Technologies de l'Information et Electroniques, Talence, France; Univ. Bordeaux, CNRS, Laboratoire IMS, UMR 5218, Talence, France.
| | - Laurent M Arsac
- Univ. Bordeaux, CNRS, Laboratoire IMS, UMR 5218, Talence, France
| | - Estelle Blons
- Univ. Bordeaux, CNRS, Laboratoire IMS, UMR 5218, Talence, France
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