bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal differences in the myoelectric activity of lower limb muscles during rearfoot and forefoot running: A statistical parametric mapping approach
Authors: Valencia Oscar , Weinstein Alejandro , Salas Rodrigo , Guzmán‐Venegas Rodrigo , Arvanitidis Michail , Martinez‐Valdes Eduardo 
Published: May 2022

ABSTRACTForefoot (FF) and rearfoot (RF) running techniques can induce different lower‐limb muscle activation patterns. However, few studies have evaluated temporal changes in the electromyographic activity (EMG) of lower limb muscles during running. The aim of this study was to compare temporal changes in EMG amplitude between RF and FF running techniques. Eleven recreational runners ran on a treadmill at a self‐selected speed, once using a RF strike pattern and once using a FF strike pattern (randomized order). The EMG of five lower limb muscles [rectus femoris (RFe), biceps femoris (BF), tibialis anterior (TA), medial and lateral gastrocnemius (MG and LG)] was evaluated, using bipolar electrodes. EMG data from the RF and FF running techniques was then processed and compared with statistical parametric mapping (SPM), dividing the analysis of the running cycle into stance and swing phases. The MG and LG muscles showed higher activation during FF running at the beginning of the stance phase and at the end of the swing phase. During the end of the swing phase, the TA muscle's EMG amplitude was higher, when the RF running technique was used. A higher level of co‐activation between the gastrocnemius and TA muscles was observed in both stance and swing phases using RF. The myoelectric behaviour of the RFe and BF muscles was similar during both running techniques. The current findings highlight that the two running techniques predominately reflect adjustments of the shank and not the thigh muscles, in both phases of the running cycle.Highlights
Statistical parametric mapping (SPM) can reveal temporal differences in muscle activity between running techniques.
The medial and lateral gastrocnemius muscles were more active at specific time‐instants of the initial stance and late swing phases during forefoot (FF) running compared to rearfoot (RF) running.
Higher activation was observed for the tibialis anterior muscle at the end of the swing phase during RF running
Contrary to the muscle activity differences observed in the leg muscles, the muscle activity of the thigh muscles was similar during RF and FF running.
Improvement in nonvolatile memory operations for metal–ferroelectric–insulator–semiconductor capacitors using HfZrO2 and ZrO2 thin films as ferroelectric and insulator layers
Authors: Kim Yeriaron , Kang Seung Youl , Woo Jiyong , Kim Jeong Hun , Im Jong-Pil , Yoon Sung-Min , Moon Seung Eon 
Published: May 2022

Abstract
Metal–ferroelectric–insulator–semiconductor (MFIS) capacitors were characterized to elucidate the optimum design schemes for the ferroelectric field-effect transistor applications. The Hf1−x
Zr
x
O2 (HZO) thin films (18 nm) were prepared on the SiO2 and ZrO2 insulator layers (ILs) with different film thicknesses. The choice of 10 nm thick ZrO2 IL was found to be an optimum condition to properly balance between the values of electric fields applied to the HZO (E
HZO) and ZrO2 (E
IL) layers, leading to effective improvement in capacitance coupling ratio and to suppression of charge injection for the MFIS capacitors. Furthermore, the crystalline natures of the crystallized HZO films were also found to be strategically controlled on the ZrO2 ILs, which can additionally enhance the E
HZO with reducing the E
IL. As consequences, the MFIS capacitors using 10 nm thick ZrO2 IL exhibited the ferroelectric memory window as large as 2.5 V at an application of ±5 V, which corresponds to 2.7 times wider value, compared to that obtained from the device using 2 nm thick SiO2 IL. Long-time memory retention and robust program endurance were also verified for the fabricated MFIS capacitors.
Measurement of rubidium vapor number density based on Faraday modulator
Authors: Shang Huining , Zhou Binquan , Quan Wei , Chi Haotian , Fang Jiancheng , Zou Sheng 
Published: May 2022

Abstract
The actual vapor density characterizing the alkali metal spin-exchange rate remains a compelling issue for spin-exchange optical pumping. Based on the deduced relationship between the Faraday rotation angle and the rubidium vapor number density using the electrodynamics theory, we report a measurement of the number density for rubidium vapor sealed inside a cell based on a Faraday modulator. The measurement relies on the optical rotation angle due to rubidium vapor under a bias magnetic field (∼0.08 T) produced by a samarium–cobalt magnet. A Faraday modulator with a lock-in amplifier is used to accurately measure the tiny optical rotation angle in a temperature range of 387–468 K. In addition, a synchronization verification is performed by the photoelastic modulator (PEM). The recurring data showed that the two methods are consistent with each other. Compared with the PEM method, the Faraday modulator detection system does not need to adjust the optical axis difference of 45° in the PEM detection system, thereby reducing the complexity of the experiment and the error caused by the alignment of the optical axis, which showed that the Faraday modulator detection method more advantageous in measuring the alkali metal density.
A class of fractional-order discrete map with multi-stability and its digital circuit realization
Authors: Liu Tianming , Mou Jun , Jahanshahi Hadi , Yan Huizhen , Cao Yinghong 
Published: May 2022

Abstract
In this paper, a class of nonlinear functions and Gaussian function are modulated to construct a new high-dimensional discrete map. Based on Caputo fractional-order difference definition, the fractional form of the map is given, and its dynamical behaviors are explored. The three discrete maps with different nonlinear functions are compared and analyzed by bifurcation diagrams and Lyapunov exponents, especially the dynamical phenomena that evolve with the order. In addition, the maps have multiple rich stability, including homogeneous and heterogeneous coexistence attractors and hyperchaos coexistence attractors. The spectral entropy (SE) algorithm is used to measure the complexity of one-dimensional and two-dimensional maps. Performance tests show that the fractional-order map has more complex dynamics than the original map. Finally, the new maps were successfully implemented on the digital platform, which shows the simplicity and feasibility of the map implementation. The experimental results provide a reference for the research on the multi-stability of fractional discrete maps.
Dynamical study of a novel three-dimensional and generalized chaotic system
Authors: Saifullah Sayed , Doungmo Goufo Emile Franc , Ali Amir 
Published: May 2022

Abstract
In this manuscript, a new three-dimensional continuous chaotic model is presented based on the modification in the Lorenz system. The dynamical aspects of the complex system are investigated, covering equilibrium points and linear stability, dissipation, phase portraits, Poincaré mapping, Lyapunov exponent, attractor projection, bifurcations, time series analysis, and sensitivity. The model is also studied numerically using the Haar wavelet scheme with Caputo fractional derivative. The positive exponent reveals that the system is chaotic. The symmetric limit cycle and butterfly type attractors are observed because the trajectories of the model ultimately progress to a bounded region. The existence of the chaotic attractor is shown by Poincaré section. In the Poincaré section, the kindling is integrated and connected as a single attractor. From the sensitivity analysis of the system, it is noted the system is dependent on the initial conditions that show chaos in the system. The evolution of the attractor is depicted by fixing the first two parameters and varying the third. The theoretical and numerical studies exhibit that the model has complex dynamics with certain stimulating physical characteristics.
Some invariant solutions of coupled Konno-Oono equations arising in electromagnetic and quantum fields
Authors: Kumar Raj , Kumar Avneesh 
Published: May 2022

Abstract
The goal of this study is to construct a novel family of travelling wave solutions for the system of (1 + 1)-coupled Konno-Oono equations (CKOEs). It occurs in optical nonlinear media, electromagnetic fields, plasma physics, and quantum fields. The invariant property of Lie symmetry analysis is exploited to extract analytical solutions. Lie symmetry analysis provides new similarity solutions for the system. A new variety of eighteen analytical solutions are compared to the reported results and the authors’ recently published work. In the previous results, a specific form of CKOEs with only two components, u and v, was solved in almost all cases, whereas in this study, a family of solutions was attained for three variables, u, v, and w. Solution profiles are portrayed via numerical simulation in order to make the solutions physically relevant.
Cosmological constraints on the decay of heavy relics into neutrinos
Authors: Hambye Thomas , Hufnagel Marco , Lucca Matteo 
Published: May 2022

Abstract
A massive particle decaying into neutrinos in the early Universe is known to be less constrained than if it was decaying into other standard model particles. However, even if the decay proceeds into neutrinos, the latter still inevitably emit secondary particles undergoing electromagnetic interactions that can be probed. We analyse in details how sensitive various cosmological probes are to such secondary particles, namely CMB anisotropies, CMB spectral distortions, and Big Bang Nucleosynthesis. For relics whose lifetime is shorter than the age of the Universe, this leads to original and stringent bounds on the particle's lifetime as a function of its abundance and mass.
522 nm single-longitudinal-mode high-frequency Pr3+:YLF laser based on pre-lase Q-switching technology
Authors: Jiang Meng , Jin Long , Liu Chang , Dong Yuan , Jin Guang-yong 
Published: May 2022

Abstract
In this work, based on the pre-lase Q-swiching technology, a single-longitudinal-mode (SLM) pulsed laser that can be emitted directly into the green spectral region at 522 nm is demonstrated for the first time. The rate equation of 522 nm Pr3+:YLF SLM Q-switched laser is established, and the output characteristics of the laser are obtained by simulation. The peak power of 37.9 W was obtained under an incident pump power of 12 W at 444 nm. At a repetition frequency of 20 kHz, the laser pulse energy and the pulse width were measured to be 3.05 μJ and 80.5 ns, respectively. The corresponding spectral linewidth is approximately 22 MHz.
More than just statics: altered complexity of dynamic amplitude of low-frequency fluctuations in the resting brain after stroke
Authors: Tian Na , Liang Liu-Ke , Luo Xue-Mao , Hu Rong-Liang , Long Wan-Sheng , Song Rong 
Published: May 2022

Abstract

Objective. Previous neuroimaging studies mainly focused on static characteristics of brain activity, and little is known about its characteristics over time, especially in post-stroke (PS) patients. In this study, we aimed to investigate the static and dynamic characteristics of brain activity after stroke using functional magnetic resonance imaging (fMRI). Approach. Twenty ischemic PS patients and nineteen healthy controls (HCs) were recruited to receive a resting-state fMRI scanning. The static amplitude of low-frequency fluctuations (sALFFs) and fuzzy entropy of dynamic ALFF (FE-dALFF) were applied to identify the stroke-induced alterations. Main results. Compared with the HCs, PS patients showed significantly increased FE-dALFF values in the right angular gyrus (ANG), bilateral precuneus (PCUN), and right inferior parietal lobule (IPL) as well as significantly decreased FE-dALFF values in the right postcentral gyrus (PoCG), right dorsolateral superior frontal gyrus (SFGdor), and right precentral gyrus (PreCG). The receiver operating characteristic analyses demonstrated that FE-dALFF and sALFF possess comparable sensitivity in distinguishing PS patients from the HCs. Moreover, a significantly positive correlation was observed between the FE-dALFF values and the Fugl-Meyer Assessment (FMA) scores in the right SFGdor (r = 0.547), right IPL (r = 0.522), and right PCUN (r = 0.486). Significance. This study provided insight into the stroke-induced alterations in static and dynamic characteristics of local brain activity, highlighting the potential of FE-dALFF in understanding neurophysiological mechanisms and evaluating pathological changes.
The Effectiveness of Chitosan Extraction from Crustaceans’ Shells as a natural coagulant
Authors: Hassan L S , Abdullah Nabihah , Abdullah Suhaila , Ghazali S R , Sobri N A M , Hashim Norazlina , Yahya N A M , Muslim W M N 
Published: May 2022

Abstract
Crustaceans’ shells are one of the resources that can be used as raw materials for chitosan extraction. Chitosan can act as bio-coagulant to remove turbidity through coagulation process. Usage of chitosan extracted from biopolymers are safer and environmentally friendly that can substitute synthetic coagulant such as alum and lime (calcium oxide) which may cause diseases to humans. This study aims to extract chitosan from waste crustaceans’ shells which are crabs (Litopenaeus Vannamei) and shrimps (Matuta Victor) as well as to analyse the effectiveness of chitosan as a natural coagulant. By using the following concentration of chemicals, 0.5N and 1N of HCl for demineralization, 0.5N and 1N of NaOH for deproteinization and, 50% of NaOH for deacetylation. Crab sample A had been the most effective against crab sample B, shrimp sample A and shrimp sample B in terms of conductivity removal percentage, TSS removal percentage, and COD removal percentage, which was 73.02%, 98.93% and 33.95% respectively. In conclusion, crustaceans’ shells contained chitosan has great potential to be used as bio-coagulant.
Electrolysis Study Effect on Electrolyzed Water as Disinfectant and Sanitizer
Authors: Nurul Aniyyah M S , Idhamnulhadi Z , Azharin Shah A A , Lili Shakirah H , Suhaila A , Norazlina H , Hajaratul Najwa M 
Published: May 2022

Abstract
The use of harmful alcohol-based disinfectants and sanitizers was a major concern throughout the CoVID-19 era. Frequent use of alcohol-based sanitizer can dry up the skin, and the effect is worsening for individuals with sensitive skin. Alcohol-based disinfectants are flammable and can ignite if used near a flame, spark, or other source of ignition. Using the electrolysis of sodium chloride (NaCl) aqueous solution method, this study aims to make Hypochlorous Acid (HOCl), a safe disinfectant and sanitizer. Two critical parameters were tested on the electrolysis effect of producing HOCl. The first is the amount of sodium chloride (NaCl) present, while the second is the type of electrode used, which are carbon, graphite, and titanium. The results showed that 10 grams of NaCl produces 50-200 ppm of HOCl, which is good for sanitizing purposes, and 30 grams of NaCl produces 500-800 ppm of HOCl, which is good for disinfecting purposes. The graphite electrode was also demonstrated to be capable of producing a clean HOCl solution. Using a UV-vis spectrophotometer, the effectiveness of the HOCl produced was determined, and it was discovered that HOCl is capable of killing bacteria. As a result, HOCl can be applied as a safe disinfectant and sanitizer in the fight against COVID-19.
Quantum Peltier coefficient resonance in a GaAs/GaAsAl parabolic quantum well with confined optical phonons
Authors: Ba Cao Thi Vi , Quynh Nguyen Thi Lam , Bau Nguyen Quang , Duc Nguyen Ba 
Published: May 2022

Abstract
The resonance of the quantum Peltier coefficient (qPC) in a parabolic quantum well (PQW) of GaAs/GaAsAl, subjected to a dc electric field, a magnetic field and a laser radiation, has been theoretically studied by using the quantum kinetic equation method with the assumption that the confined electron-confined optical phonon scattering is essential. The obtained analytical expression for the qPC in PQW is as a function of external fields, PQW parameters, and especially the quantum number m which was changed in order to characterize the influence of confined optical phonon. When m is set to zero, we obtain the results that corresponds to the case of unconfined optical phonon. Numerical calculations are also achieved for a PQW of GaAs/GaAsAl. The obtained results show that the qPC reaches resonance peaks when investigating its dependence on magnetic field and on frequency of laser radiation. Due to the influence of confined optical phonon, the position of resonance peaks has been not only shifted but also more pronounced than in the case of unconfined optical phonon. Besides, as the amplitude of laser radiation increases, the qPC has additional resonance peaks.
Research on on-line monitoring data cleaning of transformer oil chromatogram based on machine learning and neural networks
Authors: Liu Shoubao , Dang Yanyang , Li Ruijian 
Published: May 2022

Abstract
Transformer oil chromatogram on-line monitoring device is a widely used sensing device to monitor the operation state of transformer. Due to the lack of hardware verification means, the on-line chromatographic data generally has the problem of drift. In actual operation, it is mostly used as the basis for trend judgment, but can not reflect the effective value of chromatographic measurement. In this paper, the LSTM neural networks is used to correct the on-line monitoring data of transformer oil chromatogram. The off-line test data combined with neural networks data cleaning technology are used to repeatedly feed back and calibrate the online data, so that the corrected chromatographic on-line number is steadily close to the off-line detection data, which greatly improves the availability and accuracy of on-line chromatographic data. The research results of this paper have important reference significance for the data cleaning of on-line monitoring and measurement of electrical equipment.
Strontium-loaded titanium-15molybdenum surface improves physicochemical and biological properties in vitro
Authors: Matos Flávia Gomes , Santana Luís Carlos Leal , Cominotte Mariana Aline , da Silva Fernando Santos , Vaz Luís Geraldo , de Oliveira Diego Pedreira , Cirelli Joni Augusto 
Published: May 2022

Abstract
The titanium alloy composition and microdesign affect the dynamic interplay between the bone cells and titanium surface in the osseointegration process. The current study aimed to evaluate the surface physicochemical properties, electrochemical stability, and the metabolic response of the MC3T3-E1 cells (pre-osteoblast cell line) cultured onto titanium-15molybdenum (Ti-15Mo) discs treated with phosphoric acid (H3PO4) and sodium hydroxide (NaOH) and/or strontium-loading by the hydrothermal method. The x-ray dispersive energy spectroscopy (EDS) and x-ray diffraction (XRD) analysis showed no trace of impurities and the possible formation of hydrated strontium oxide (H2O2Sr), respectively. The confocal laser microscopy (CLSM) analysis indicated that titanium samples treated with strontium (Sr) showed greater surface roughness. The acid/alkali treatment prior to the hydrothermal Sr deposition improved the surface free energy and resistance to corrosion of the Ti-15Mo alloy. The acid/alkali treatment also provided greater retention of the Sr particles on the Ti-15Mo surfaces accordingly with inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. The AlamarBlue and fluorescence analysis indicated noncytotoxic effects against the MC3T3-E1 cells, which allowed cells’ adhesion and proliferation, with greater cells’ spreading in the Sr-loaded Ti-15Mo samples. These findings suggest that Sr deposition by the hydrothermal method has the potential to enhance the physicochemical properties of the Ti-15Mo previously etched with H3PO4 and NaOH, and also improve the initial events related to cell-mediated bone deposition.
Modeling surface pH measurements of oocytes
Authors: Bocchinfuso A , Calvetti D , Somersalo E 
Published: May 2022

Abstract
The transport of gases across cell membranes plays a key role in many different cell functions, from cell respiration to pH control. Mathematical models play a central role in understanding the factors affecting gas transport through membranes, and are the tool needed for testing the novel hypothesis of the preferential crossing through specific gas channels. Since the surface pH of cell membrane is regulated by the transport of gases such as CO2 and NH3, inferring the membrane properties can be done indirectly from pH measurements. Numerical simulations based on recent models of the surface pH support the hypothesis that the presence of a measurement device, a liquid-membrane pH sensitive electrode on the cell surface may disturb locally the pH, leading to a systematic bias in the measured values. To take this phenomenon into account, it is necessary to equip the model with a description of the micro-environment created by the pH electrode. In this work we propose a novel, computationally lightweight numerical algorithm to simulate the surface pH data. The effect of different parameters of the model on the output are investigated through a series of numerical experiments with a physical interpretation.
Analysis of free vibration of tapered cracked double nanobeams using Maclaurin series
Authors: Hossain Mainul , Lellep Jaan 
Published: May 2022

Abstract
In the study, the Maclaurin series technique is presented to analyse the vibration of cracked tapered double nanobeams. The equation of motion is derived from the Euler–Bernoulli beam theory based on the Hamiltonian principle and Eringen’s nonlocal theory of elasticity. The double-nanobeam system consists of two parallel nanobeams attached by a Winkler elastic layer. Both beams are identical and their widths vary along the x-axis. A single crack is considered at the upper beam of the system. The mechanical behaviour of cracked cross-sections is simulated by the local stiffness model. According to the model, the cracked double-beam system is divided into two intact segments. A numerical investigation is carried out to scrutinize the effects of nonlocal parameters, crack severity, taper ratio, and spring constant on the vibration of the double nanobeam. The results reveal that the effects of crack depth, crack location, nonlocal parameters, taper ratio, and spring constant influence the natural frequency and dynamic response of the system significantly. This study highlights that a crack at the upper beam influences the mode shape of the upper beam as well as the intact lower beam. Numerical results have been examined with the previously published works and found a good agreement with them.