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Approximate entropy

Ram Sewak Singh, Barjinder Singh Saini, Ramesh Kumar Sunkaria
Objective: Cardiovascular diseases generate the highest mortality in the globe population, mainly due to coronary artery disease (CAD) like arrhythmia, myocardial infarction and heart failure. Therefore, an early identification of CAD and diagnosis is essential. For this, we have proposed a new approach to detect the CAD patients using heart rate variability (HRV) signals. This approach is based on subspaces decomposition of HRV signals using multiscale wavelet packet (MSWP) transform and entropy features extracted from decomposed HRV signals...
2018: Clujul Medical (1957)
Julian Lee
Time-reversal symmetry of the microscopic laws dictates that the equilibrium distribution of a stochastic process must obey the condition of detailed balance. However, cyclic Markov processes that do not admit equilibrium distributions with detailed balance are often used to model systems driven out of equilibrium by external agents. I show that for a Markov model without detailed balance, an extended Markov model can be constructed, which explicitly includes the degrees of freedom for the driving agent and satisfies the detailed balance condition...
March 2018: Physical Review. E
Katsuhide Yutani, Yoshinori Matsuura, Hisashi Naitow, Yasumasa Joti
In order to elucidate features of the denatured state ensembles that exist in equilibrium with the native state under physiological conditions, we performed 1.4-μs molecular dynamics (MD) simulations at 400 K and 450 K using the monomer subunits of three CutA1 mutants from Escherichia coli: an SH-free mutant (Ec0SH) with denaturation temperature (Td ) = 85.6 °C, a hydrophobic mutant (Ec0VV) with Td  = 113.3 °C, and an ionic mutant (Ec0VV_6) with Td  = 136.8 °C. The occupancy of salt bridges by the six substituted charged residues in Ec0VV_6 was 140...
May 16, 2018: Scientific Reports
Hiromi Otsuka, Yutaka Okabe, Konstantin Nefedev
We investigate dilution effects on the classical spin-ice materials such as Ho_{2}Ti_{2}O_{7} and Dy_{2}Ti_{2}O_{7}. In particular, we derive a formula of the thermodynamic quantities as functions of the temperature and a nonmagnetic ion concentration based on a Husimi-cactus approximation. We find that the formula predicts a dilution-induced crossover from the cooperative to the conventional paramagnets in a ground state, and that it also reproduces the "generalized Pauling's entropy" given by Ke et al...
April 2018: Physical Review. E
T Shakirov, W Paul
What is the thermodynamic driving force for the crystallization of melts of semiflexible polymers? We try to answer this question by employing stochastic approximation Monte Carlo simulations to obtain the complete thermodynamic equilibrium information for a melt of short, semiflexible polymer chains with purely repulsive nonbonded interactions. The thermodynamics is obtained based on the density of states of our coarse-grained model, which varies by up to 5600 orders of magnitude. We show that our polymer melt undergoes a first-order crystallization transition upon increasing the chain stiffness at fixed density...
April 2018: Physical Review. E
Jenny Farmer, Donald Jacobs
In high throughput applications, such as those found in bioinformatics and finance, it is important to determine accurate probability distribution functions despite only minimal information about data characteristics, and without using human subjectivity. Such an automated process for univariate data is implemented to achieve this goal by merging the maximum entropy method with single order statistics and maximum likelihood. The only required properties of the random variables are that they are continuous and that they are, or can be approximated as, independent and identically distributed...
2018: PloS One
Yunxiao Du, Shuyi Wang, Nyakuru Zaphlene Ndaro, Yan Zuo
The purpose of this study is to compare the differences among neck muscle fatigue evaluation algorithms and to find a more effective algorithm which can provide a human factor quantitative evaluation method for neck muscle fatigue during bending over the desk. We collected surface electromyography signal of sternocleidomastoid muscle of 15 subjects using wireless physiotherapy Bio-Radio when they bent over the desk using memory pillows for 12 minutes. Five algorithms including mean power frequency, spectral moments ratio, discrete wavelet transform, fuzzy approximation entropy and the complexity algorithms were used to calculate the corresponding muscle fatigue index...
February 1, 2018: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
Xin Li, Erjuan Cai, Yanxiu Tian, Xiaoqi Sun, Mengdi Fan
The result of the emotional state induced by music may provide theoretical support and help for assisted music therapy. The key to assessing the state of emotion is feature extraction of the emotional electroencephalogram (EEG). In this paper, we study the performance optimization of the feature extraction algorithm. A public multimodal database for emotion analysis using physiological signals (DEAP) proposed by Koelstra et al . was applied. Eight kinds of positive and negative emotions were extracted from the dataset, representing the data of fourteen channels from the different regions of brain...
August 1, 2017: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
Taranpal Bansal, Gulam S Haji, Harry B Rossiter, Mike I Polkey, James H Hull
BACKGROUND: Breathing pattern disorder (BPD) is a prevalent cause of exertional dyspnea and yet there is currently no reliable objective measure for its diagnosis. We propose that statistical analysis of ventilatory irregularity, quantified by approximate entropy (ApEn), could be used to detect BPD when applied to cardiopulmonary exercise test (CPET) data. We hypothesized that ApEn of ventilatory variables (tidal volume (VT ), breathing frequency (Bf ), minute ventilation (VE )) would be greater, i...
May 3, 2018: Respiratory Physiology & Neurobiology
Vasanth Sukumar, Arathi Radhakrishnan, Venkatesh H Keshavan
Background and Aims: Sound knowledge about effect site concentration (Ce) of propofol aids in smooth induction, maintenance and early recovery. We studied the correlation between Ce of propofol at loss of response to verbal command and recovery concentration using target-controlled infusion (TCI) in Indian patients who underwent spine surgeries. Methods: Ninety patients undergoing spine surgeries were included. Total intravenous anaesthesia (TIVA) technique with TCI for propofol using modified Marsh model was used...
April 2018: Indian Journal of Anaesthesia
Gaetano Valenza, Luca Iozzia, Luca Cerina, Luca Mainardi, Riccardo Barbieri
BACKGROUND: There is a fast growing interest in the use of non-contact devices for health and performance assessment in humans. In particular, the use of non-contact videophotoplethysmography (vPPG) has been recently demonstrated as a feasible way to extract cardiovascular information. Nevertheless, proper validation of vPPG-derived heartbeat dynamics is still missing. OBJECTIVE: We aim to an in-depth validation of time-varying, linear and nonlinear/complex dynamics of the pulse rate variability extracted from vPPG...
May 2018: Methods of Information in Medicine
Jamie Pethick, Samantha L Winter, Mark Burnley
NEW FINDINGS: In this study we show that the fatigue-induced loss of isometric torque complexity does not recover if the fatigued muscle's blood flow is occluded during recovery, suggesting a pivotal role for peripheral mechanisms in this effect. When the contralateral limb is fatigued, the complexity of isometric torque output is unaffected even if the contralateral limb's blood flow is occluded, which suggests neither central fatigue nor afferent feedback from ischaemic muscle influence the complexity of torque output in an otherwise fresh muscle...
May 2, 2018: Experimental Physiology
Maximilian Pilhatsch, Tasha Glenn, Natalie Rasgon, Martin Alda, Kemal Sagduyu, Paul Grof, Rodrigo Munoz, Wendy Marsh, Scott Monteith, Emanuel Severus, Rita Bauer, Philipp Ritter, Peter C Whybrow, Michael Bauer
BACKGROUND: Polypharmacy is often prescribed for bipolar disorder, yet medication non-adherence remains a serious problem. This study investigated the regularity in the daily dosage taken of mood stabilizers and second generation antipsychotics. METHODS: Daily self-reported data on medications taken and mood were available from 241 patients with a diagnosis of bipolar disorder who received treatment as usual. Patients who took the same mood stabilizer or second generation antipsychotic for ≥ 100 days were included...
May 1, 2018: International Journal of Bipolar Disorders
Xiang Zhang, Jiarui Sun, Siwei Ma, Zhouchen Lin, Jian Zhang, Shiqi Wang, Wen Gao
Sparse representation leads to an efficient way to approximately recover a signal by the linear composition of a few bases from a learnt dictionary based on which various successful applications have been achieved. However, in the scenario of data compression, its efficiency and popularity are hindered. It is because of the fact that encoding sparsely distributed coefficients may consume more bits for representing the index of nonzero coefficients. Therefore, introducing an accurate rate constraint in sparse coding and dictionary learning becomes meaningful, which has not been fully exploited in the context of sparse representation...
August 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Baltej Singh, M K Gupta, R Mittal, S L Chaplot
We have used the ab initio density functional theory technique to understand the phase transitions and structural changes in various high temperature/pressure phases of LiAlO2. The electronic band structure as well as phonon spectra is calculated for various phases as a function of pressure. The phonon entropy used for the calculations of Gibbs free energy is found to play an important role in the phase stability and phase transitions among various phases. A sudden increase in the polyhedral bond lengths (Li/Al-O) signifies the change from the tetrahedral to octahedral geometry at high-pressure phase transitions...
April 24, 2018: Physical Chemistry Chemical Physics: PCCP
Tuan-Wu Cao, Wen-Bing Huang, Jian-Wei Shi, Wei He
Scrophularia ningpoensis has exhibited a variety of biological activities and been used as a pharmaceutical product for the treatment of inflammatory ailment, rheumatoid arthritis, osteoarthritis and so on. Harpagoside (HAR) is considerer as a main bioactive compound in this plant. Serum albumin has important physiological roles in transportation, distribution and metabolism of many endogenous and exogenous substances in body. It is of great significance to study the interaction mechanism between HAR and bovine serum albumin (BSA)...
March 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Georg Bier, Simone Bier, Malte Niklas Bongers, Ahmed Othman, Ulrike Ernemann, Johann-Martin Hempel
PURPOSE: Tumorous texture is a marker for tumor tissue inhomogeneity. Based on this assumption, this study aims to evaluate the value of computed tomography texture analysis for imaging-based prediction of perioperative complications during laparoscopic partial tumor nephrectomy. METHODS: A total of 106 patients with histologically confirmed renal cell carcinoma and pre-operative CT were included and volumetric texture analysis of the tumors was performed by two readers...
2018: PloS One
Sabina Stefan, Barbara Schorr, Alex Lopez-Rolon, Iris-Tatjana Kolassa, Jonathan P Shock, Martin Rosenfelder, Suzette Heck, Andreas Bender
We applied the following methods to resting-state EEG data from patients with disorders of consciousness (DOC) for consciousness indexing and outcome prediction: microstates, entropy (i.e. approximate, permutation), power in alpha and delta frequency bands, and connectivity (i.e. weighted symbolic mutual information, symbolic transfer entropy, complex network analysis). Patients with unresponsive wakefulness syndrome (UWS) and patients in a minimally conscious state (MCS) were classified into these two categories by fitting and testing a generalised linear model...
April 17, 2018: Brain Topography
Martha G Pamato, Ian G Wood, David P Dobson, Simon A Hunt, Lidunka Vočadlo
On the basis of ab initio computer simulations, pre-melting phenomena have been suggested to occur in the elastic properties of hexagonal close-packed iron under the conditions of the Earth's inner core just before melting. The extent to which these pre-melting effects might also occur in the physical properties of face-centred cubic metals has been investigated here under more experimentally accessible conditions for gold, allowing for comparison with future computer simulations of this material. The thermal expansion of gold has been determined by X-ray powder diffraction from 40 K up to the melting point (1337 K)...
April 1, 2018: Journal of Applied Crystallography
Christoph P Sager, Brigitte Fiege, Pascal Zihlmann, Raghu Vannam, Said Rabbani, Roman P Jakob, Roland C Preston, Adam Zalewski, Timm Maier, Mark W Peczuh, Beat Ernst
Seven-membered ring mimetics of mannose were studied as ligands for the mannose-specific bacterial lectin FimH, which plays an essential role in the first step of urinary tract infections (UTI). A competitive binding assay and isothermal titration calorimetry (ITC) experiments indicated an approximately ten-fold lower affinity for the seven-membered ring mannose mimetic 2- O-n -heptyl-1,6-anhydro-d- glycero -d-galactitol ( 7 ) compared to n -heptyl α-d-mannopyranoside ( 2 ), resulting exclusively from a loss of conformational entropy...
January 21, 2018: Chemical Science
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