bluuebunny/crossref_metadata_2025 huggingface dataset:
Co0.5Mn0.5Fe2O4@PMMA Nanoparticles Promotes Preosteoblast Differentiation through Activation of OPN-BGLAP2-DMP1 Axis and Modulates Osteoclastogenesis under Magnetic Field Conditions
Authors: Marycz Krzysztof , Turlej Eliza , Kornicka-Garbowska Katarzyna , Zachanowicz Emilia , Tomaszewska Anna , Kulpa-Greszta Magdalena , Pązik Robert
Published: September 2021

The prevalence of osteoporosis in recent years is rapidly increasing. For this reason, there is an urgent need to develop bone substitutes and composites able to enhance the regeneration of damaged tissues which meet the patients’ needs. In the case of osteoporosis, personalized, tailored materials should enhance the impaired healing process and restore the balance between osteoblast and osteoclast activity. In this study, we fabricated a novel hybrid material (Co0.5Mn0.5Fe2O4@PMMA) and investigated its properties and potential utility in the treatment of osteoporosis. The material structure was investigated with X-ray diffraction, Fourier-transform infrared spectroscopy with attenuated total reflectance, FTIR-ATR, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and selected area (electron) diffraction (SAED). Then, the biological properties of the material were investigated with pre-osteoblast (MC3T3-E1) and pre-osteoclasts (4B12) and in the presence or absence of magnetic field, using RT-qPCR and RT-PCR. During the studies, we established that the impact of the new hybrids on the pre-osteoblasts and pre-osteoclasts could be modified by the presence of the magnetic field, which could influence on the PMMA covered by magnetic nanoparticles impact on the expression of genes related to the apoptosis, cells differentiation, adhesion, microRNAs or regulating the inflammatory processes in both murine cell lines. In summary, the Co0.5Mn0.5Fe2O4@PMMA hybrid may represent a novel approach for material optimization and may be a way forward in the fabrication of scaffolds with enhanced bioactivity that benefits osteoporotic patients.
Numerical Reliability Study Based on Rheological Input for Bingham Paste Pumping Using a Finite Volume Approach in OpenFOAM
Authors: De Schryver Robin , El Cheikh Khadija , Lesage Karel , Yardimci Mert Yücel , De Schutter Geert
Published: September 2021

Rheological quantification is important in many industries, the concrete industry in particular, e.g., pumping, form filling, etc. Instead of performing expensive and time-consuming experiments, numerical simulations are a powerful means in view of rheological assessment. However, due to the unclear numerical reliability and the uncertainty of rheological input data, it is important for the construction industry to assess the numerical outcome. To reduce the numerical domain of cementitious suspensions, we assessed the numerical finite volume simulations of Bingham paste pumping flows in OpenFOAM. We analysed the numerical reliability, first, irrespective of its rheological input by comparison with the literature and theory, and second, dependent on a certain rheological quantification by comparison with pumping experiments. Irrespective of the rheological input, the numerical results were significantly accurate. Dependent on the rheological input, a numerical mismatch, however, existed. Errors below 1% can be expected for proposed numerical rules of thumb: a bi-viscous regularisation, with pressure numbers higher than 5/4. To improve bias due to uncertain rheology, a rheological configuration close to the engineer’s aimed application should be used. However, important phenomena should not be overlooked. Further assessment for lubrication flows, in, e.g., concrete pumping, is still necessary to address concerns of reliability and stability.
Damage Detection at a Reinforced Concrete Specimen with Coda Wave Interferometry
Authors: Grabke Stefan , Clauß Felix , Bletzinger Kai-Uwe , Ahrens Mark Alexander , Mark Peter , Wüchner Roland
Published: September 2021

Reinforced concrete is a widely used construction material in the building industry. With the increasing age of structures and higher loads there is an immense demand for structural health monitoring of built infrastructure. Coda wave interferometry is a possible candidate for damage detection in concrete whose applicability is demonstrated in this study. The technology is based on a correlation evaluation of two ultrasonic signals. In this study, two ways of processing the correlation data for damage detection are compared. The coda wave measurement data are obtained from a four-point bending test at a reinforced concrete specimen that is also instrumented with fibre optic strain measurements. The used ultrasonic signals have a central frequency of 60 kHz which is a significant difference to previous studies. The experiment shows that the coda wave interferometry has a high sensitivity for developing cracks and by solving an inverse problem even multiple cracks can be distinguished. A further specialty of this study is the use of finite elements for solving a diffusion problem which is needed to state the previously mentioned inverse problem for damage localization.
A Short Note about the Impact Action of a Water Jet Stabilized by a Coaxial Air Stream in the Air and Underwater
Authors: Poláček Josef , Hlaváčová Irena Marie , Tyč Martin
Published: September 2021

A new original method, applying a coaxial protective airflow, was tested aiming to improve the pure water jet efficiency in surface layer removal or medium hard materials cutting or blasting. The dual action of the air flow is expected: the air co-flowing the water jet with approximately the same velocity should prevent the central jet from breaking up into tiny droplets in the near field, and simultaneously, it should support jet decomposition into big parts with enough destructive potential in the far-field. A brief survey of the relevant literature dealing with the water jet instability is presented, introducing four recognized breakup regimes. An original cutting head designed to generate a waterjet surrounded by protective coaxial air flow is introduced. The submitted device is supposed to operate within the first wind-induced regime. Two types of experiments, consisting of blasting limestone bricks placed either in the air or underwater, were realized. The depths of kerfs produced with different water pressures and air overpressures were evaluated. While no substantial positive effect was recognized in the air performance, the submerged blasting of the same material under similar conditions appeared to be promising.
Corrosion Inhibition of Mild Steel and 304 Stainless Steel in 1 M Hydrochloric Acid Solution by Tea Tree Extract and Its Main Constituents
Authors: Kim Jae-Yeon , Shin Inji , Byeon Jai-Won
Published: September 2021

Tea tree extract, containing antioxidant constituents α-terpineol, terpinen-4-ol, and α-terpinene, has a wide range of applications in the cosmetic, food, and pharmaceutical industries. In this study, tea tree extract showed an anticorrosive effect under 1 M HCl solution on mild steel (MS) and 304 stainless steel (STS). Uniform corrosion for MS and pitting corrosion for STS at 298 K were retarded, with inhibition efficiencies of 77% and 86%, respectively. The inhibition of uniform and pitting corrosion was confirmed by scanning electron microscopy and laser scanning confocal microscopy in terms of surface roughness and pitting morphologies. The most effective constituent contributing to the inhibitory performance of tea tree extract was revealed to be α-terpineol, with an inhibition efficiency of 83%. The adsorption of tea tree extract was confirmed by surface characterization analysis using Fourier transform infrared spectroscopy, Raman spectroscopy, and Electrochemical impedance spectroscopy. Interestingly, G- and D-peaks of Raman spectra were detected from the inhibited steels, and this finding is the first example in the corrosion inhibition field. The anticorrosion mechanism can be explained by the formation of organic-Fe complexes on the corroded steel surface via electron donor and acceptor interactions in the presence of an oxygen atom of the hydroxyl group or ether of organic inhibitors.
High Performance Tunable Catalysts Prepared by Using 3D Printing
Authors: Chaparro-Garnica Cristian Yesid , Bailón-García Esther , Davó-Quiñonero Arantxa , Da Costa Patrick , Lozano-Castelló Dolores , Bueno-López Agustín
Published: September 2021

Honeycomb monoliths are the preferred supports in many industrial heterogeneous catalysis reactions, but current extrusion synthesis only allows obtaining parallel channels. Here, we demonstrate that 3D printing opens new design possibilities that outperform conventional catalysts. High performance carbon integral monoliths have been prepared with a complex network of interconnected channels and have been tested for carbon dioxide hydrogenation to methane after loading a Ni/CeO2 active phase. CO2 methanation rate is enhanced by 25% at 300 °C because the novel design forces turbulent flow into the channels network. The methodology and monoliths developed can be applied to other heterogeneous catalysis reactions, and open new synthesis options based on 3D printing to manufacture tailored heterogeneous catalysts.
Pressure-Induced Variation of the Crystal Stacking Order in the Hydrogen-Bonded Quasi-Two-Dimensional Layered Material Cu(OH)Cl
Authors: Tian Hui , Wang Meiling , Zhang Jian , Ma Yanmei , Cui Hang , Zhao Jiaxin , Dong Qing , Cui Qiliang , Liu Bingbing
Published: September 2021

The crystal stacking order plays a crucial role in determining the structure and physical properties of 2D layered materials. A variation in the stacking sequence of adjacent 2D building blocks causes drastic changes in their functionalities. In this work, the structural variation of belloite (Cu(OH)Cl), as a function of pressure, is presented. Through in situ synchrotron X-ray diffraction and Raman scattering studies, in combination with first-principles theoretical simulations, a structural transformation from the initial monoclinic phase into an orthorhombic one has been established at 18.7 GPa, featuring variations in the stacking sequence of the tectonic monolayers. In the monoclinic phase, they are arranged in an AAAA sequence. While in the orthorhombic phase, the monolayers are stacked in an ABAB sequence. Such phenomena are similar to those observed in van der Waals 2D materials, with pressure-induced changes in the stacking order between layers. In addition, an isostructural phase transition within the initial monoclinic phase is also observed to occur at 12.9–16 GPa, which is associated with layer-sliding and a change in hydrogen bond configuration. These results show that Cu(OH)Cl, as well as other hydrogen-bonded 2D layered materials, can provide a convenient platform for studying the effects of the crystal stacking order.
Comprehensive Study on the Mechanism of Sulfating Roasting of Zinc Plant Residue with Iron Sulfates
Authors: Grudinsky Pavel , Pankratov Denis , Kovalev Dmitry , Grigoreva Darya , Dyubanov Valery
Published: September 2021

Zinc plant residue (ZPR) is a secondary material generated during hydrometallurgical zinc production that contains considerable contents of valuable elements such as Zn, Cu, Fe, Pb, Cd, Ag, In, Ga, Tl. Zinc, copper and accompanying elements in ZPR are in different minerals, mainly in the ferrites. A promising approach for recycling ZPR is the sulfating roasting using iron sulfates followed by water leaching. In this study, the composition of ZPR and the obtained products were thoroughly investigated by various methods including X-ray diffraction analysis (XRD), chemical phase analysis and Mössbauer spectroscopy. The effect of temperature, amount of iron sulfates and roasting time on the conversion of valuable metals into a water-soluble form was thermodynamically and experimentally studied both using pure ferrites and ZPR. Based on the results of time-resolved XRD analysis and synchronous thermal analysis (STA), a mechanism of the sulfation roasting was elucidated. The rate-controlling step of zinc and copper sulfation process during the ZPR roasting was estimated. The sulfating roasting at 600 °C during 180 min with the optimal Fe2(SO4)3∙9H2O addition followed by water leaching enables to recover 99% Zn and 80.3% Cu, while Fe, Pb, Ag, In, Ga retained almost fully in the residue.
Compressive Creep and Shrinkage of High-Strength Concrete Based on Limestone Coarse Aggregate Applied to High-Rise Buildings
Authors: Hwang Euichul , Kim Gyuyong , Koo Kyungmo , Moon Hyungjae , Choe Gyeongcheol , Suh Dongkyun , Nam Jeongsoo
Published: September 2021

Concrete undergoes shrinkage regardless of the influence of external forces. The deformation of concrete is crucial for the structural stability of high-rise and large-scale buildings. In this study, the shrinkage and compressive creep of 70–90 MPa high-strength concrete used in high-rise buildings were evaluated based on the curing conditions (sealed/unsealed), and the existing prediction models were examined. It was observed that the curing condition does not significantly affect the mechanical properties of high-strength concrete, but the use of limestone coarse aggregate increases the elastic modulus when compared to granite coarse aggregate. The autogenous shrinkage of high-strength concrete is greater than that of normal-strength concrete owing to self-desiccation, resulting in a large variation from the value predicted by the model. The drying shrinkage was observed to be similar to that predicted by the model. Compressive creep was affected by the curing conditions, compressive strength, loading level, and loading age. The compressive creep of high-strength concrete varied significantly from the prediction results of ACI 209; ACI 209 was modified based on the measured values. The shrinkage and compressive creep characteristics of high-strength concrete must be reflected to predict the deformation of an actual structure exposed to various conditions.
Investigation on Green Synthesis, Biocompatibility, and Antibacterial Activity of Silver Nanoparticles Prepared Using Cistus incanus
Authors: Florkiewicz Wioletta , Pluta Klaudia , Malina Dagmara , Rudnicka Karolina , Żywicka Anna , Guigou Martin Duarte , Tyliszczak Bożena , Sobczak-Kupiec Agnieszka
Published: September 2021

This paper describes the plant-mediated preparation of silver nanoparticles with aqueous extract and infusion of Cistus incanus leaves. To evaluate aqueous extract and infusion antioxidant capacity and total phenolic content the DPPH and Folin–Ciocalteau methods were utilized. The antioxidant capacity and total phenolic content of extract and infusion were equal to 85.97 ± 6.54 mg gallic acid equivalents per gram of dry weight.; 10.76 ± 0.59 mg/mL and 12.65 ± 1.04 mg gallic acid equivalents per gram of dry weight.; 3.10 ± 0.14 mg/mL, respectively. The formed nanoparticles displayed the characteristic absorption band in the 380–450 nm wavelength range. The average size of particles was in the 68.8–71.2 nm range. Morphology and phase composition analysis revealed the formation of spherical nanoparticles with a face-centred cubic structure. Immune compatibility tests of nanoparticles and plant extracts showed no activation of the THP1-XBlue™ monocyte. Cytotoxicity tests performed with L929 mice fibroblasts showed that nanoparticles should be utilized at a concentration of 16 ppm. The minimum inhibitory concentrations determined with the microdilution method for nanoparticles prepared with plant infusion for S. aureus and S. epidermidis were 2 ppm and 16 ppm, respectively.
Molecular Dynamics Research on the Impact of Vacancies on Cu Precipitation in BCC-Fe
Authors: Zhang Haichao , Chen Yinli , Wang Xufeng , Li Huirong , Li Yungang
Published: September 2021

The molecular dynamics (MD) simulation method was used to explore the impact of vacancy concentration (0 at%, 0.1 at% and 0.2 at%) on the diffusion and precipitation rate of Cu atoms in the Fe-3.5Cu alloy and the growth of Cu precipitation during the aging process of the alloy. The mechanism of the influence of Cu precipitation relative to the tensile properties of Fe-3.5Cu alloy was investigated. The results showed that the presence of vacancies will promote the diffusion and precipitation of Cu atoms in the Fe-3.5Cu alloy, but the diffusion and precipitation rate of Cu atoms does not always increase with the increase in vacancies. In the alloy containing 0.2 at% vacancies, the diffusion and precipitation rate of Cu atoms is lower than that in the alloy containing 0.1 at% vacancies. During the aging process, when the alloy contains no vacancies, no Cu precipitates will be produced. In the alloy containing 0.1 at% vacancies, the size of the Cu precipitates produced is larger than the size of the Cu precipitates produced in the alloy containing 0.2 at% vacancies, but the number of precipitates is less than that in the alloy with 0.2 at% vacancies. During the tensile process, the Cu precipitates will promote early occurrence of phase transition of the internal crystal structure in the Fe-3.5Cu alloy system, and lead to the generation of vacancy defects in the system, thus weakening the yield strength and strain hardening strength of the alloy.
The Initial Algebraic Knowledge of Preservice Teachers
Authors: Zapatera Alberto , Quevedo Eduardo
Published: September 2021

Early algebra proposes to incorporate algebra in primary school from the first years of schooling. The success of this incorporation depends, to a large extent, on the training of teachers, so the objective of this article is to study whether the degree of algebraic knowledge of student teachers at the beginning of their training. To conduct this, 106 preservice teachers were given a questionnaire. This survey is based on two daily life situations. They had to propose tasks to develop algebraic reasoning in primary school students. Most of the participants designed tasks in which they assigned specific values to the indeterminate ones and solved them arithmetically. In this way, they transformed open situations and numerous opportunities to promote algebraic thinking in students through the generalization and representation of relationships and functions into closed single-solution problems that do not promote algebraic thinking. We can see from the results that the participants’ algebraic knowledge is insufficient. Therefore, it is necessary to include in their training process the programs and experiences that will allow them to design tasks in order to detect and promote algebraic thinking in their future students. Sequences of tasks are presented to develop both situations by generalizing and representing relationships and functions, which can serve as a starting point for future training programs and experiences.
Learning Effect in a Multilingual Web-Based Argumentative Writing Instruction Model, Called ECM, on Metacognition, Rhetorical Moves, and Self-Efficacy for Scientific Purposes
Authors: Arroyo González Rosario , Fernández-Lancho Eric , Maldonado Jurado Juan Antonio
Published: September 2021

The purpose of this study is to assess the learning effect of a multilingual web-based argumentative writing instruction model called the Ensayo Científico Multilingüe (ECM, Multilingual Scientific Essay) adapting the didactic model called Genre-based Writing Instruction (GBWI) in an experiment conducted over three months. For this purpose, a quasi-experimental research model was applied to 150 students in the experimental group and 150 in the control group, with two measurements, pre and post-test, for three dependent variables: (a) writing metacognition and its dimensions; (b) written argumentative self-efficacy; and (c) rhetorical moves and steps of an argumentative essay. The latter variable was measured by the content analysis method. Variables (a) and (b) were both measured with instruments validated in a population of 518 university students using structural equations. The findings demonstrate the positive effect of the ECM, which combines WBWI and GBWI in argumentative written learning in the students’ mother tongue in all variables measured, applying statistics such as the Shapiro–Wilk statistic, parametric contrast, and the Wilcoxon signed-rank test. In relation to the findings, with respect to the evaluated variables, it was discovered, specifically, that the rhetorical steps in which the students showed a significant improvement were innovations, quotes/research, definitions of concepts, refutations, definitive reasons, and bibliographical references. Likewise, the rhetorical steps that did not present significant differences following the application of the ECM were discovered, and they were: reason summary, formulation of premise, and reasons for. Furthermore, it can be stated that for the ECM there was an increase, above all, in awareness of the following metacognitive dimensions: (a) writing self-regulation; (b) writing planning; and (c) writing revision, as well as argumentative self-efficacy. The novelties of this research with respect to the precedents reside in that it offers valid and concrete results on the effect of a multilingual web design integrated into a well-defined didactic model of argumentative writing on writing metacognition and its dimensions, argumentative structuring and its rhetorical steps, and argumentative self-efficacy. The related studies consider only some of these variables, but not all of them together or their complexity. These results have allowed us to establish specific didactic–technological proposals for improving the ECM that are transferable to didactic designs to guide written argumentation at higher academic levels using multilingual web technologies and integrating the metacognitive, behavioral, and motivational dimensions of writing.
Isometry Invariant Shape Recognition of Projectively Perturbed Point Clouds by the Mergegram Extending 0D Persistence
Authors: Elkin Yury , Kurlin Vitaliy
Published: September 2021

Rigid shapes should be naturally compared up to rigid motion or isometry, which preserves all inter-point distances. The same rigid shape can be often represented by noisy point clouds of different sizes. Hence, the isometry shape recognition problem requires methods that are independent of a cloud size. This paper studies stable-under-noise isometry invariants for the recognition problem stated in the harder form when given clouds can be related by affine or projective transformations. The first contribution is the stability proof for the invariant mergegram, which completely determines a single-linkage dendrogram in general position. The second contribution is the experimental demonstration that the mergegram outperforms other invariants in recognizing isometry classes of point clouds extracted from perturbed shapes in images.
Multiple Loop Fuzzy Neural Network Fractional Order Sliding Mode Control of Micro Gyroscope
Authors: Fang Yunmei , Chen Fang , Fei Juntao
Published: September 2021

In this paper, an adaptive double feedback fuzzy neural fractional order sliding control approach is presented to solve the problem that lumped parameter uncertainties cannot be measured and the parameters are unknown in a micro gyroscope system. Firstly, a fractional order sliding surface is designed, and the fractional order terms can provide additional freedom and improve the control accuracy. Then, the upper bound of lumped nonlinearities is estimated online using a double feedback fuzzy neural network. Accordingly, the gain of switching law is replaced by the estimated value. Meanwhile, the parameters of the double feedback fuzzy network, including base widths, centers, output layer weights, inner gains, and outer gains, can be adjusted in real time in order to improve the stability and identification efficiency. Finally, the simulation results display the performance of the proposed approach in terms of convergence speed and track speed.
Special Functions of Fractional Calculus in the Form of Convolution Series and Their Applications
Authors: Luchko Yuri
Published: September 2021

In this paper, we first discuss the convolution series that are generated by Sonine kernels from a class of functions continuous on a real positive semi-axis that have an integrable singularity of power function type at point zero. These convolution series are closely related to the general fractional integrals and derivatives with Sonine kernels and represent a new class of special functions of fractional calculus. The Mittag-Leffler functions as solutions to the fractional differential equations with the fractional derivatives of both Riemann-Liouville and Caputo types are particular cases of the convolution series generated by the Sonine kernel κ(t)=tα−1/Γ(α),0<α<1. The main result of the paper is the derivation of analytic solutions to the single- and multi-term fractional differential equations with the general fractional derivatives of the Riemann-Liouville type that have not yet been studied in the fractional calculus literature.
Analysis of Multi-Server Queue with Self-Sustained Servers
Authors: Dudin Alexander , Dudina Olga , Dudin Sergei , Samouylov Konstantin
Published: September 2021

A novel multi-server vacation queuing model is considered. The distinguishing feature of the model, compared to the standard queues, is the self-sufficiency of servers. A server can terminate service and go on vacation independently of the system manager and the overall situation in the system. The system manager can make decisions whether to allow the server to start work after vacation completion and when to try returning some server from a vacation to process customers. The arrival flow is defined by a general batch Markov arrival process. The problem of optimal choice of the total number of servers and the thresholds defining decisions of the manager arises. To solve this problem, the behavior of the system is described by the three-dimensional Markov chain with the special block structure of the generator. Conditions for the ergodicity of this chain are derived, the problem of computation of the steady-state distribution of the chain is discussed. Expressions for the key performance indicators of the system in terms of the distribution of the chain states are derived. An illustrative numerical result is presented.
Relay Synchronization in a Weighted Triplex Network
Authors: Anwar Md Sayeed , Ghosh Dibakar , Frolov Nikita
Published: September 2021

Relay synchronization in multi-layer networks implies inter-layer synchronization between two indirectly connected layers through a relay layer. In this work, we study the relay synchronization in a three-layer multiplex network by introducing degree-based weighting mechanisms. The mechanism of within-layer connectivity may be hubs-repelling or hubs-attracting whenever low-degree or high-degree nodes receive strong influence. We adjust the remote layers to hubs-attracting coupling, whereas the relay layer may be unweighted, hubs-repelling, or hubs-attracting network. We establish that relay synchronization is improved when the relay layer is hubs-repelling compared to the other cases. We determine analytically necessary stability conditions of relay synchronization state using the master stability function approach. Finally, we explore the relation between synchronization and the topological property of the relay layer. We find that a higher clustering coefficient hinders synchronizability, and vice versa. We also look into the intra-layer synchronization in the proposed weighted triplex network and establish that intra-layer synchronization occurs in a wider range when relay layer is hubs-attracting.
Pythagorean Membership Grade Aggregation Operators: Application in Financial knowledge
Authors: Blanco-Mesa Fabio , León-Castro Ernesto , Romero-Muñoz Jorge
Published: September 2021

This paper presents the Pythagorean membership grade induced ordered weighted moving average (PMGIOWMA) operator with some particular cases and theorems. The main advantage of this new operator is that can include the knowledge, expectation, and aptitude of the decision maker into the Pythagorean membership function by using a weighting vector and induced variables. An application in financial knowledge based on a survey conducted in 13 provinces in Boyacá, Colombia, is presented.
Domination in Fuzzy Directed Graphs
Authors: Enriquez Enrico , Estrada Grace , Loquias Carmelita , Bacalso Reuella J , Ocampo Lanndon
Published: September 2021

A new domination parameter in a fuzzy digraph is proposed to espouse a contribution in the domain of domination in a fuzzy graph and a directed graph. Let GD*=V,A be a directed simple graph, where V is a finite nonempty set and A=x,y:x,y∈V,x≠y. A fuzzy digraph GD=σD,μD is a pair of two functions σD:V→0,1 and μD:A→0,1, such that μDx,y≤σDx∧σDy, where x,y∈V. An edge μDx,y of a fuzzy digraph is called an effective edge if μDx,y=σDx∧σDy. Let x,y∈V. The vertex σDx dominates σDy in GD if μDx,y is an effective edge. Let S⊆V, u∈V\S, and v∈S. A subset σDS⊆σD is a dominating set of GD if, for every σDu∈σD\σDS, there exists σDv∈σDS, such that σDv dominates σDu. The minimum dominating set of a fuzzy digraph GD is called the domination number of a fuzzy digraph and is denoted by γGD. In this paper, the concept of domination in a fuzzy digraph is introduced, the domination number of a fuzzy digraph is characterized, and the domination number of a fuzzy dipath and a fuzzy dicycle is modeled.
Planar Typical Bézier Curves with a Single Curvature Extremum
Authors: He Chuan , Zhao Gang , Wang Aizeng , Li Shaolin , Cai Zhanchuan
Published: September 2021

This paper focuses on planar typical Bézier curves with a single curvature extremum, which is a supplement of typical curves with monotonic curvature by Y. Mineur et al. We have proven that the typical curve has at most one curvature extremum and given a fast calculation formula of the parameter at the curvature extremum. This will allow designers to execute a subdivision at the curvature extremum to obtain two pieces of typical curves with monotonic curvature. In addition, we put forward a sufficient condition for typical curve solutions under arbitrary degrees for the G1 interpolation problem. Some numerical experiments are provided to demonstrate the effectiveness and efficiency of our approach.
Time-Delay Synchronization and Anti-Synchronization of Variable-Order Fractional Discrete-Time Chen–Rossler Chaotic Systems Using Variable-Order Fractional Discrete-Time PID Control
Authors: Padron Joel Perez , Perez Jose Paz , Pérez Díaz José Javier , Martinez Huerta Atilano
Published: September 2021

In this research paper, we solve the problem of synchronization and anti-synchronization of chaotic systems described by discrete and time-delayed variable fractional-order differential equations. To guarantee the synchronization and anti-synchronization, we use the well-known PID (Proportional-Integral-Derivative) control theory and the Lyapunov–Krasovskii stability theory for discrete systems of a variable fractional order. We illustrate the results obtained through simulation with examples, in which it can be seen that our results are satisfactory, thus achieving synchronization and anti-synchronization of chaotic systems of a variable fractional order with discrete time delay.
Instruments and Methods for Identifying Indicators of a Digital Entrepreneurial System
Authors: Raut Jelena , Ćelić Đorđe , Dudić Branislav , Ćulibrk Jelena , Stefanović Darko
Published: September 2021

Entrepreneurial ecosystems are the main driver of the widespread trend of digitalization, and they open opportunities for the advancement of the digital economy. The digital economy makes its progress through innovative enterprises that can ensure global progress. In order to effectively use the opportunities that open up the process of digitalization, information is needed on how much the Republic of Serbia is able to support the process of discovering entrepreneurship, which is stimulated by digitalization, which is the subject of this paper. The aim of this paper is to analyze the digital entrepreneurial system of the Republic of Serbia, as well as to identify indicators that hinder the development of this system, using appropriate instruments and methods that will be presented in detail in the paper. The results have demonstrated that the starting point for improvement of the digital entrepreneurial system is in the field of finance, with a particular focus on companies in the startup and stand-up phases. Furthermore, a comparative analysis will showcase the digital entrepreneurial system of the Republic of Serbia and the member states of the European Union, where it will be seen that the digital entrepreneurial system of the Republic of Serbia is lagging behind the member states of the European Union in its growth and development. The results will serve as the starting point for policymakers to improve the process of digitalization and the digital entrepreneurial system as a whole. The results show the starting point for the improvement of entrepreneurship in the Republic of Serbia, that is, how small, and medium-sized enterprises can be encouraged on the path to their successful management.
Arbitrary Coefficient Assignment by Static Output Feedback for Linear Differential Equations with Non-Commensurate Lumped and Distributed Delays
Authors: Zaitsev Vasilii , Kim Inna
Published: September 2021

We consider a linear control system defined by a scalar stationary linear differential equation in the real or complex space with multiple non-commensurate lumped and distributed delays in the state. In the system, the input is a linear combination of multiple variables and its derivatives, and the output is a multidimensional vector of linear combinations of the state and its derivatives. For this system, we study the problem of arbitrary coefficient assignment for the characteristic function by linear static output feedback with lumped and distributed delays. We obtain necessary and sufficient conditions for the solvability of the arbitrary coefficient assignment problem by the static output feedback controller. Corollaries on arbitrary finite spectrum assignment and on stabilization of the system are obtained. We provide an example illustrating our results.
Dynamics of Stage-Structured Predator–Prey Model with Beddington–DeAngelis Functional Response and Harvesting
Authors: Li Haiyin , Cheng Xuhua
Published: September 2021

In this paper, we investigate the stability of equilibrium in the stage-structured and density-dependent predator–prey system with Beddington–DeAngelis functional response. First, by checking the sign of the real part for eigenvalue, local stability of origin equilibrium and boundary equilibrium are studied. Second, we explore the local stability of the positive equilibrium for τ=0 and τ≠0 (time delay τ is the time taken from immaturity to maturity predator), which shows that local stability of the positive equilibrium is dependent on parameter τ. Third, we qualitatively analyze global asymptotical stability of the positive equilibrium. Based on stability theory of periodic solutions, global asymptotical stability of the positive equilibrium is obtained when τ=0; by constructing Lyapunov functions, we conclude that the positive equilibrium is also globally asymptotically stable when τ≠0. Finally, examples with numerical simulations are given to illustrate the obtained results.
A Novel Method for Solving Second Kind Volterra Integral Equations with Discontinuous Kernel
Authors: Noeiaghdam Samad , Micula Sanda
Published: September 2021

Load leveling problems and energy storage systems can be modeled in the form of Volterra integral equations (VIE) with a discontinuous kernel. The Lagrange–collocation method is applied for solving the problem. Proving a theorem, we discuss the precision of the method. To control the accuracy, we apply the CESTAC (Controle et Estimation Stochastique des Arrondis de Calculs) method and the CADNA (Control of Accuracy and Debugging for Numerical Applications) library. For this aim, we apply discrete stochastic mathematics (DSA). Using this method, we can control the number of iterations, errors and accuracy. Additionally, some numerical instabilities can be identified. With the aid of this theorem, a novel condition is used instead of the traditional conditions.
A Unique Urinary Metabolic Feature for the Determination of Bladder Cancer, Prostate Cancer, and Renal Cell Carcinoma
Authors: Lee Sujin , Ku Ja Yoon , Kang Byeong Jin , Kim Kyung Hwan , Ha Hong Koo , Kim Suhkmann
Published: September 2021

Prostate cancer (PCa), bladder cancer (BCa), and renal cell carcinoma (RCC) are the most prevalent cancer among urological cancers. However, there are no cancer-specific symptoms that can differentiate them as well as early clinical signs of urological malignancy. Furthermore, many metabolic studies have been conducted to discover their biomarkers, but the metabolic profiling study to discriminate between these cancers have not yet been described. Therefore, in this study, we aimed to investigate the urinary metabolic differences in male patients with PCa (n = 24), BCa (n = 29), and RCC (n = 12) to find the prominent combination of metabolites between cancers. Based on 1H NMR analysis, orthogonal partial least-squares discriminant analysis was applied to find distinct metabolites among cancers. Moreover, the ranked analysis of covariance by adjusting a potential confounding as age revealed that 4-hydroxybenzoate, N-methylhydantoin, creatinine, glutamine, and acetate had significantly different metabolite levels among groups. The receiver operating characteristic analysis created by prominent five metabolites showed the great discriminatory accuracy with area under the curve (AUC) > 0.7 for BCa vs. RCC, PCa vs. BCa, and RCC vs. PCa. This preliminary study compares the metabolic profiles of BCa, PCa, and RCC, and reinforces the exploratory role of metabolomics in the investigation of human urine.
Editorial for the Special Issue on Semiconductor Infrared Devices and Applications
Authors: Perera A. G. Unil
Published: September 2021

Infrared radiation (IR) was accidentally discovered in 1800 by the astronomer Sir William Herschel [...]
Cis- and Trans-Encoded Small Regulatory RNAs in Bacillus subtilis
Authors: Brantl Sabine , Müller Peter
Published: September 2021

Small regulatory RNAs (sRNAs) that act by base-pairing are the most abundant posttranscriptional regulators in all three kingdoms of life. Over the past 20 years, a variety of approaches have been employed to discover chromosome-encoded sRNAs in a multitude of bacterial species. However, although largely improved bioinformatics tools are available to predict potential targets of base-pairing sRNAs, it is still challenging to confirm these targets experimentally and to elucidate the mechanisms as well as the physiological role of their sRNA-mediated regulation. Here, we provide an overview of currently known cis- and trans-encoded sRNAs from B. subtilis with known targets and defined regulatory mechanisms and on the potential role of RNA chaperones that are or might be required to facilitate sRNA regulation in this important Gram-positive model organism.
Polyphenol-Hydroxylating Tyrosinase Activity under Acidic pH Enables Efficient Synthesis of Plant Catechols and Gallols
Authors: Song Hanbit , Lee Pyung-Gang , Kim Hyun , Lee Uk-Jae , Lee Sang-Hyuk , Kim Joonwon , Kim Byung-Gee
Published: September 2021

Tyrosinase is generally known as a melanin-forming enzyme, facilitating monooxygenation of phenols, oxidation of catechols into quinones, and finally generating biological melanin. As a homologous form of tyrosinase in plants, plant polyphenol oxidases perform the same oxidation reactions specifically toward plant polyphenols. Recent studies reported synthetic strategies for large scale preparation of hydroxylated plant polyphenols, using bacterial tyrosinases rather than plant polyphenol oxidase or other monooxygenases, by leveraging its robust monophenolase activity and broad substrate specificity. Herein, we report a novel synthesis of functional plant polyphenols, especially quercetin and myricetin from kaempferol, using screened bacterial tyrosinases. The critical bottleneck of the biocatalysis was identified as instability of the catechol and gallol under neutral and basic conditions. To overcome such instability of the products, the tyrosinase reaction proceeded under acidic conditions. Under mild acidic conditions supplemented with reducing agents, a bacterial tyrosinase from Bacillus megaterium (BmTy) displayed efficient consecutive two-step monophenolase activities producing quercetin and myricetin from kaempferol. Furthermore, the broad substrate specificity of BmTy toward diverse polyphenols enabled us to achieve the first biosynthesis of tricetin and 3′-hydroxyeriodictyol from apigenin and naringenin, respectively. These results suggest that microbial tyrosinase is a useful biocatalyst to prepare plant polyphenolic catechols and gallols with high productivity, which were hardly achieved by using other monooxygenases such as cytochrome P450s.
The Impact of Human Herpesviruses in Clinical Practice of Inflammatory Bowel Disease in the Era of COVID-19
Authors: Hosomi Shuhei , Nishida Yu , Fujiwara Yasuhiro
Published: September 2021

Human herpesviruses (HHVs): herpes simplex virus (HSV) types 1 (HSV-1) and 2 (HSV-2), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), HHV-6, HHV-7, and HHV-8, are known to be part of a family of DNA viruses that cause several diseases in humans. In clinical practice of inflammatory bowel disease (IBD), the complication of CMV enterocolitis, which is caused by CMV reactivation under disruption of intestinal barrier function, inflammation, or strong immunosuppressive therapy, is well known to affect the prognosis of disease. However, the relationship between other HHVs and IBD remains unclear. In the transplantation field, reactivation of other viruses, such as HHV-6, could cause colitis under immunosuppressed condition. Recent research revealed that combined infection of some HHVs could be a risk factor for colectomy in patients with ulcerative colitis. This suggests that it would be important to clarify HHV behavior in the treatment for patients with IBD, especially in those under immunosuppressive therapies. Looking at the relationship with recently emerged novel coronaviruses (SARS-CoV-2), there are reports describe that SARS-CoV-2 might induce reactivation of HSV-1, EBV, VZV (herpes zoster), and HHV-6/7. If SARS-CoV-2 infection becomes common, vigilance against HHV reactivation may become more crucial. In this review, we discuss the impact of HHVs in clinical practice of inflammatory bowel diseases, especially during the SARS-CoV-2 pandemic.
Current and Emerging Therapies to Combat Cystic Fibrosis Lung Infections
Authors: Manos Jim
Published: September 2021

The ultimate aim of any antimicrobial treatment is a better infection outcome for the patient. Here, we review the current state of treatment for bacterial infections in cystic fibrosis (CF) lung while also investigating potential new treatments being developed to see how they may change the dynamics of antimicrobial therapy. Treatment with antibiotics coupled with regular physical therapy has been shown to reduce exacerbations and may eradicate some strains. Therapies such as hypertonic saline and inhaled PulmozymeTM (DNase-I) improve mucus clearance, while modifier drugs, singly and more successfully in combination, re-open certain mutant forms of the cystic fibrosis transmembrane conductance regulator (CFTR) to enable ion passage. No current method, however, completely eradicates infection, mainly due to bacterial survival within biofilm aggregates. Lung transplants increase lifespan, but reinfection is a continuing problem. CFTR modifiers normalise ion transport for the affected mutations, but there is conflicting evidence on bacterial clearance. Emerging treatments combine antibiotics with novel compounds including quorum-sensing inhibitors, antioxidants, and enzymes, or with bacteriophages, aiming to disrupt the biofilm matrix and improve antibiotic access. Other treatments involve bacteriophages that target, infect and kill bacteria. These novel therapeutic approaches are showing good promise in vitro, and a few have made the leap to in vivo testing.
K1 Antigen Is Associated with Different AST Profile in Escherichia coli: A One-Month-Long Pilot Study
Authors: Proquot Maelys , Jamal Lovasoa Najaraly , Plouzeau-Jayle Chloe , Michaud Anthony , Broutin Lauranne , Burucoa Christophe , Cremniter Julie , Pichon Maxime
Published: September 2021

Escherichia coli is responsible for diseases of varying severity. The “K” antigen designates the capsular polysaccharides on the bacterial surface, which are mostly similar to those of highly pathogenic bacteria. The K1 antigen is often found in pathogenic E. coli. Aim: While the published studies on the AST profile of K1-positive E. coli have focused on pregnant women or newborns, this study aimed to characterize the AST profile of K1-positive E. coli independently of the clinical sample of isolation. Over a 4-week-long period, all patients hospitalized/consulting at the Poitiers University Hospital presenting a determined AST on E. coli were prospectively included to define their K1-status (Pastorex Meningitis) and to collect the clinical (age/sex) or biological metadata (AST/MIC). Among the 296 included samples, no differential representation was observed between K1 results regarding sample nature. K1-negative results were associated with multiple antibiotic-resistance (12.3% vs. 33.0%; p < 0.01). AST phenotypes differed between these groups, with a higher proportion of K1-negativity among resistant strains, especially on β-lactams (ureidopenicillin, 25.8% vs. 14.9%; and ampicillin/inhibitor, 50.0% vs. 26.8%; p < 0.05) or quinolone (19.8% vs. 7.0%) and sulfamethoxazole-trimethoprim (30.2% vs. 12.3%) (p < 0.01). This study analyzed E. coli ASTs in clinical samples of all types, regarding their K1-antigen status.
Feasibility Study on the Potential Replacement of Primary Raw Materials in Traditional Ceramics by Clayey Overburden Sterile from the Prosilio Region (Western Macedonia, Greece)
Authors: Christogerou Angeliki , Lampropoulou Paraskevi , Papoulis Dimitrios , Angelopoulos George N.
Published: September 2021

The objective of this study was to investigate the valorization potential of clayey overburden sterile materials from lignite-mining activities in the manufacturing of traditional ceramics. This study aims to contribute toward the sustainable management and use of such waste materials in line with the environmental objectives of the 2030 agenda. To assess this issue, clayey steriles were incorporated in a white clay-body at 20, 50, and 80 wt%, whereas reference samples were also formed from the individual raw materials. Laboratory processing of the ceramics was performed by dry pressing loose powder into rectangular samples and firing at 1000 °C for 4 h. Characterization of the raw materials included chemical, mineralogical, and thermal analysis. The fired bodies were tested for their total linear shrinkage, apparent porosity, water absorption, bulk density, and bending strength according to the relevant standards. The microstructural evolution of the final bodies was analyzed by scanning electron microscopy, which observed differences related to the addition of the steriles. The results showed that the tested clayey steriles can be utilized up to 50 wt% as a secondary raw material in the production of ceramic materials (e.g., bricks) with comparable properties to the reference clay-bodies. Furthermore, the color of the final samples changed from white-creamy to reddish as the content of clayey sterile materials increased in the raw mix.