bluuebunny/crossref_metadata_2025 huggingface dataset:
State-of-the-Art Treatments for Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy
Authors: Penela Diego , Sorgente Antonio , Cappato Riccardo
Published: July 2021

Atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM) are two very common clinical entities, which often occur simultaneously, giving a hard time to both patients and cardiologists. Myocyte hypertrophy, myocyte disarray and interstitial fibrosis in the left atrium (LA) predisposes to atrial arrhythmias due to modifications of the substrate that promote re-entry. AF is usually poorly tolerated due to the shortening of the diastolic time with rapid heart rates and the lack of the atrial contribution to the diastolic filling in patients who often have a previous diastolic dysfunction. AF onset frequently results in exercise intolerance and recurrent heart failure admissions and also has prognostic implications. Early maintenance of sinus rhythm appears as a worthy approach in these patients, especially when started early in the course of the disease. However, treatment with antiarrhythmic (AA) agents in HCM patients is less effective than in patients without the disease, and concerns regarding safety frequently limit the long-term adherence. Catheter ablation has limited efficacy in patients with persistent AF but can play an important role in patients with paroxysmal AF, emphasizing the importance of an accurate patient selection. The aim of this review is to provide an overview of the pathophysiology of combined HCM and AF and the principal pharmacological and non-pharmacological treatments recommended in this complex clinical scenario.
Effect of Wood Fiber Surface Treatment on the Properties of Recycled HDPE/Maple Fiber Composites
Authors: Fletes Roberto C. Vázquez , Rodrigue Denis
Published: July 2021

This work reports on the production and characterization of recycled high density polyethylene (R-HDPE) composites reinforced with maple fibers. The composites were produced by a simple dry-blending technique followed by compression molding. Furthermore, a fiber surface treatment was performed using a coupling agent (maleated polyethylene, MAPE) in solution. FTIR, TGA/DTG, and density analyses were performed to confirm any changes in the functional groups on the fiber surface, which was confirmed by SEM-EDS. As expected, the composites based on treated fiber (TC) showed improved properties compared to composites based on untreated fiber (UC). In particular, MAPE was shown to substantially improve the polymer–fiber interface quality, thus leading to better mechanical properties in terms of tensile modulus (23%), flexural modulus (54%), tensile strength (26%), and flexural strength (46%) as compared to the neat matrix. The impact resistance also increased by up to 87% for TC as compared to UC. In addition, the maximum fiber content to produce good parts increased from 15 to 75 wt% when treated fiber was used. These composites can be seen as sustainable materials and possible alternatives for the development of low-cost building/construction/furniture applications.
Densification of Ceramic Matrix Composite Preforms by Si2N2O Formed by Reaction of Si with SiO2 under High Nitrogen Pressure. Part 1: Materials Synthesis
Authors: Taillet Brice , Pailler René , Teyssandier Francis
Published: July 2021

Ceramic matrix composites (CMCs) have been designed and developed for extreme operating environments. The aim of the present study is to look for a rapid densification process providing a high level of material performance. The fibrous preform was made of Hi-Nicalon S fibers woven in a 3D interlock weave. The matrix was composed of Si2N2O prepared inside the CMCs by reacting a mixture of Si and SiO2 under high nitrogen pressure (1 to 3 MPa). Silica was either impregnated by slurry or obtained by oxidation of silicon grains inside the preform. The synthesis reaction was initiated by heating the impregnated preform by means of a carbon resistor submitted to Joule effect. Composition, homogeneity and porosity of the formed matrix were studied and interpreted as a function of the experimental parameters (nitrogen pressure, heating rate of the preform) as well as the recorded thermal history of the process. The present results show that the matrix formation is almost completed in less than one minute. Melting of silicon has a major influence on the process. Competition was observed between the formation of Si3N4 and Si2N2O, which could be mainly controlled by the heating rate of the preform and the nitrogen partial pressure.
HOSVD-Based Algorithm for Weighted Tensor Completion
Authors: Chao Zehan , Huang Longxiu , Needell Deanna
Published: July 2021

Matrix completion, the problem of completing missing entries in a data matrix with low-dimensional structure (such as rank), has seen many fruitful approaches and analyses. Tensor completion is the tensor analog that attempts to impute missing tensor entries from similar low-rank type assumptions. In this paper, we study the tensor completion problem when the sampling pattern is deterministic and possibly non-uniform. We first propose an efficient weighted Higher Order Singular Value Decomposition (HOSVD) algorithm for the recovery of the underlying low-rank tensor from noisy observations and then derive the error bounds under a properly weighted metric. Additionally, the efficiency and accuracy of our algorithm are both tested using synthetic and real datasets in numerical simulations.
Long-Term Trends of Sea Surface Wind in the Northern South China Sea under the Background of Climate Change
Authors: Hong Bo , Zhang Jie
Published: July 2021

The long-term trends of sea surface wind are of great importance to our understanding of the effects of climate change on the marine environment. In the northern South China Sea (SCS), the long-term changes in coastal sea surface wind are not well-understood. Based on the latest reanalysis (ERA5) data from 1979 to 2019, our analysis showed a decreasing trend in the annual mean wind speed in the coastal area and an increasing trend in the open sea. There was a significant weakening trend in the easterly wind component in the coastal and continental shelf areas, whereas there was an increasing trend in the northerly wind component in the open sea. The Mann–Kendall mutation analysis suggested that there were significant changes in the wind speed and frequency of strong wind. Significant correlations were found between the variation of the wind field and El Niño–Southern Oscillation by wave coherence analysis. The strengthening of the wind stress curl was an important factor for the enhancement of coastal upwelling along the coast of the northern SCS. The wind field plays an important role in modulating the climatic change of significant wave height.
Sea Surface Object Detection Algorithm Based on YOLO v4 Fused with Reverse Depthwise Separable Convolution (RDSC) for USV
Authors: Liu Tao , Pang Bo , Zhang Lei , Yang Wei , Sun Xiaoqiang
Published: July 2021

Unmanned surface vehicles (USVs) have been extensively used in various dangerous maritime tasks. Vision-based sea surface object detection algorithms can improve the environment perception abilities of USVs. In recent years, the object detection algorithms based on neural networks have greatly enhanced the accuracy and speed of object detection. However, the balance between speed and accuracy is a difficulty in the application of object detection algorithms for USVs. Most of the existing object detection algorithms have limited performance when they are applied in the object detection technology for USVs. Therefore, a sea surface object detection algorithm based on You Only Look Once v4 (YOLO v4) was proposed. Reverse Depthwise Separable Convolution (RDSC) was developed and applied to the backbone network and feature fusion network of YOLO v4. The number of weights of the improved YOLO v4 is reduced by more than 40% compared with the original number. A large number of ablation experiments were conducted on the improved YOLO v4 in the sea ship dataset SeaShips and a buoy dataset SeaBuoys. The experimental results showed that the detection speed of the improved YOLO v4 increased by more than 20%, and mAP increased by 1.78% and 0.95%, respectively, in the two datasets. The improved YOLO v4 effectively improved the speed and accuracy in the sea surface object detection task. The improved YOLO v4 algorithm fused with RDSC has a smaller network size and better real-time performance. It can be easily applied in the hardware platforms with weak computing power and has shown great application potential in the sea surface object detection.
MFS1, a Pleiotropic Transporter in Dermatophytes That Plays a Key Role in Their Intrinsic Resistance to Chloramphenicol and Fluconazole
Authors: Yamada Tsuyoshi , Yaguchi Takashi , Salamin Karine , Guenova Emmanuella , Feuermann Marc , Monod Michel
Published: July 2021

A recently identified Trichophyton rubrum major facilitator superfamily (MFS)-type transporter (TruMFS1) has been shown to give resistance to azole compounds and cycloheximide (CYH) when overexpressed in Saccharomyces cerevisiae. We investigated the roles of MFS1 in the intrinsic resistance of dermatophytes to CYH and chloramphenicol (CHL), which are commonly used to isolate these fungi, and to what extent MFS1 affects the susceptibility to azole antifungals. Susceptibility to antibiotics and azoles was tested in S. cerevisiae overexpressing MFS1 and ΔMFS1 mutants of Trichophyton benhamiae, a dermatophyte that is closely related to T. rubrum. We found that TruMFS1 functions as an efflux pump for CHL in addition to CYH and azoles in S. cerevisiae. In contrast, the growth of T. benhamiae ΔMFS1 mutants was not reduced in the presence of CYH but was severely impaired in the presence of CHL and thiamphenicol, a CHL analog. The suppression of MFS1 in T. benhamiae also increased the sensitivity of the fungus to fluconazole and miconazole. Our experiments revealed a key role of MFS1 in the resistance of dermatophytes to CHL and their high minimum inhibitory concentration for fluconazole. Suppression of MFS1 did not affect the sensitivity to CYH, suggesting that another mechanism was involved in resistance to CYH in dermatophytes.
Acute Exposure to Bisphenol A Causes Oxidative Stress Induction with Mitochondrial Origin in Saccharomyces cerevisiae Cells
Authors: Ďurovcová Ivana , Goffa Eduard , Šestáková Zuzana , Mániková Dominika , Gaplovská-Kyselá Katarína , Chovanec Miroslav , Ševčovičová Andrea
Published: July 2021

Bisphenol A (BPA) is a major component of the most commonly used plastic products, such as disposable plastics, Tetra Paks, cans, sport protective equipment, or medical devices. Due to the accumulation of excessive amounts of plastic waste and the subsequent release of BPA into the environment, BPA is classified as a pollutant that is undesirable in the environment. To date, the most interesting finding is the ability of BPA to act as an endocrine disrupting compound due to its binding to estrogen receptors (ERs), and adverse physiological effects on living organisms may result from this action. Since evidence of the potential pro-oxidizing effects of BPA has accumulated over the last years, herein, we focus on the detection of oxidative stress and its origin following BPA exposure using pulsed-field gel electrophoresis, flow cytometry, fluorescent microscopy, and Western blot analysis. Saccharomyces cerevisiae cells served as a model system, as these cells lack ERs allowing us to dissect the ER-dependent and -independent effects of BPA. Our data show that high concentrations of BPA affect cell survival and cause increased intracellular oxidation in yeast, which is primarily generated in the mitochondrion. However, an acute BPA exposure does not lead to significant oxidative damage to DNA or proteins.
Credibility in Online Health Communities: Effects of Moderator Credentials and Endorsement Cues
Authors: Kanthawala Shaheen , Peng Wei
Published: July 2021

Online health communities (OHCs) are a common and highly frequented health resource. To create safer resources online, we must know how users think of credibility in these spaces. To understand how new visitors may use cues present within the OHC to establish source credibility, we conducted an online experiment (n = 373) manipulating cues for perceptions of two primary dimensions of credibility—trustworthiness and expertise—by manipulating the presence of endorsement cues (i.e., likes) and of moderators’ health credentials (i.e., medical professional) using a fake OHC. Participants were predominantly male (60.4%) and Caucasian (74.1%). Our findings showed that moderators with health credentials had an effect on both dimensions of source credibility in OHCs, however, likes did not. We also observed a correlation between the perceived social support within the community and both dimensions of source credibility, underscoring the value of supportive online health communities. Our findings can help developers ascertain areas of focus within their communities and users with how perceptions of credibility could help or hinder their own assessments of OHC credibility.
The Development of a Small and Medium-Sized Business Risk Management Intervention Tool
Authors: Krüger Niël Almero , Meyer Natanya
Published: July 2021

Risk is inevitable in business. For large companies, risk management is formalised and structured through compliance with industry standards. However, small and medium-sized businesses (SMEs) rarely have adequate resources to develop their own standards or conform to pre-established criteria. This results in an increased vulnerability to risk, which tends to undermine SMEs’ sustainability. The primary reasons for the low adoption rate of risk management are related to the tremendous initial difficulty in orientating the business concerning risk and the significant investment of the workforce in developing and implementing a structured managerial process. The objective of this paper is to produce a guided process tool for small and medium-sized businesses with which they can identify, evaluate, and appropriately address risks from an SME perspective. Moreover, this intervention would offer enhancements at no cost beyond the time of its implementation. In order to identify what constitutes holistic risk management, document analysis was applied, which utilised risk management standards, academic articles, books, and regulatory policy and strategy documentation. The identified elements were integrated with a tool that improves business owners’ capacity to position themselves in context with their daily risk management challenges.
Visible Light Communications through Diffusive Illumination of Sculptures in a Real Museum
Authors: Meucci Marco , Seminara Marco , Tarani Fabio , Riminesi Cristiano , Catani Jacopo
Published: July 2021

The recent, massive diffusion of LED-based illumination devices makes Visible Light Communications (VLC) a widely recognised wireless communication technology with large potential impact in many indoor and outdoor applications. In the indoor scenario, one of the most promising VLC implementations is foreseen in museums, exhibitions and cultural heritage sites. In this context, digital data can be transmitted by the specific lighting system of each artwork and received by the nearby standing visitors, allowing a complete set of dedicated services such as augmented reality (AR) and real-time indoor positioning, exploiting the directionality of the optical channel. In this work, we achieve, for the first time, VLC transmission through diffusive LED illumination of three-dimensional artworks (wooden and marble sculptures) in a real museum, exploiting the available LED illumination system, demonstrating the feasibility of VLC technology also when complex three-dimensional artworks, such as sculptures or bas-reliefs, are involved. In our experimental campaign, performed inside the Basilica of Santa Maria Novella in Florence, we perform extensive Packet Error Rate (PER) and Signal-to-Noise Ratio (SNR) tests on two important wooden and marble sculptures (Crucifix by Brunelleschi and the Holy Water Font by Bordoni, respectively), for different distances, view angles and configurations, in order to mimic a wide set of situations that visitors may encounter in a realistic scenario. We achieve successful VLC transmission for distances up to 8 m from artworks, at baud rate of 28 kBaud. We also provide detailed results on the characterization of the transmission Field of View (FoV) for our prototype, as well as the effect of side shifts of the observer’s position on the quality of VLC transmission, providing essential information for future implementations of positioning protocols and dedicated services in realistic, indoor scenarios. Our work represents an important step forward towards the deployment of VLC technology in museums and, more in general, it opens for far-reaching developments in a wide set of real indoor environments, including the cultural heritage sector, where diffusive VLC links exploiting illumination of three-dimensional objects could represent a ground-breaking innovation.
Mitochondrial Genomic Landscape: A Portrait of the Mitochondrial Genome 40 Years after the First Complete Sequence
Authors: Formaggioni Alessandro , Luchetti Andrea , Plazzi Federico
Published: July 2021

Notwithstanding the initial claims of general conservation, mitochondrial genomes are a largely heterogeneous set of organellar chromosomes which displays a bewildering diversity in terms of structure, architecture, gene content, and functionality. The mitochondrial genome is typically described as a single chromosome, yet many examples of multipartite genomes have been found (for example, among sponges and diplonemeans); the mitochondrial genome is typically depicted as circular, yet many linear genomes are known (for example, among jellyfish, alveolates, and apicomplexans); the chromosome is normally said to be “small”, yet there is a huge variation between the smallest and the largest known genomes (found, for example, in ctenophores and vascular plants, respectively); even the gene content is highly unconserved, ranging from the 13 oxidative phosphorylation-related enzymatic subunits encoded by animal mitochondria to the wider set of mitochondrial genes found in jakobids. In the present paper, we compile and describe a large database of 27,873 mitochondrial genomes currently available in GenBank, encompassing the whole eukaryotic domain. We discuss the major features of mitochondrial molecular diversity, with special reference to nucleotide composition and compositional biases; moreover, the database is made publicly available for future analyses on the MoZoo Lab GitHub page.
Presence of Lactic Acid Bacteria in the Intestinal Tract of the Mediterranean Trout (Salmo macrostigma) in Its Natural Environment
Authors: Iorizzo Massimo , Albanese Gianluca , Testa Bruno , Ianiro Mario , Letizia Francesco , Succi Mariantonietta , Tremonte Patrizio , D’Andrea Mariasilvia , Iaffaldano Nicolaia , Coppola Raffaele
Published: July 2021

Knowledge of the composition of the gut microbiota in freshwater fish living in their natural habitat has taxonomic and ecological importance. Few reports have been produced on the composition of the gut microbiota and on the presence of LAB in the intestines of freshwater fish that inhabit river environments. In this study, we investigated the LAB community that was present in the gastrointestinal tract (GIT) of Mediterranean trout (Salmo macrostigma) that colonized the Biferno and Volturno rivers of the Molise region (Italy). The partial 16S rRNA gene sequences of these strains were determined for the species-level taxonomic placement. The phylogenetic analysis revealed that the isolated LABs belonged to seven genera (Carnobacterium, Enterococcus, Lactobacillus, Lactiplantibacillus, Vagococcus, Lactococcus, and Weissella). The study of the enzymatic activities showed that these LABs could contribute to the breakdown of polysaccharides, proteins, and lipids. In future studies, a greater understanding of how the LABs act against pathogens and trigger the fish immune response may provide practical means to engineer the indigenous fish microbiome and enhance disease control and fish health.
Synthesis of the Guanidine Derivative: N-{[(7-(4,5-Dihydro-1H-imidazol-2-yl)-2-(p-tolyl)-6,7-dihydro-2H-imidazo[2,1-c][1,2,4]triazol-3(5H)-ylidene)amino](phenylamino)methylene}benzamide
Authors: Balewski Łukasz , Kornicka Anita
Published: July 2021

The guanidine derivative N-{[(7-(4,5-dihydro-1H-imidazol-2-yl)-2-(p-tolyl)-6,7-dihydro-2H-imidazo[2,1-c][1,2,4]triazol-3(5H)-ylidene)amino](phenylamino)methylene}benzamide (3) has been obtained by the reaction of one measure of N-{[7-(4,5-dihydro-1H-imidazol-2-yl)-2-(p-tolyl)-6,7-dihydro-2H-imidazo[2,1-c][1,2,4]triazol-3(5H)-ylidene]carbamothioyl}benzamide (2) with one measure of aniline in the presence of mercury(II) chloride and triethylamine in anhydrous dimethylformamide. The structure of product 3 was confirmed by 1H and 13C-NMR, infrared spectroscopy, and elemental analysis.
Ambient-Temperature Synthesis of (E)-N-(3-(tert-Butyl)-1-methyl-1H-pyrazol-5-yl)-1-(pyridin-2-yl)methanimine
Authors: Becerra Diana , Cobo Justo , Castillo Juan-Carlos
Published: July 2021

We report the ambient-temperature synthesis of novel (E)-N-(3-(tert-butyl)-1-methyl-1H-pyrazol-5-yl)-1-(pyridin-2-yl)methanamine 3 in 81% yield by a condensation reaction between 3-(tert-butyl)-1-methyl-1H-pyrazol-5-amine 1 and 2-pyridinecarboxaldehyde 2 in methanol using magnesium sulfate as a drying agent. The N-pyrazolyl imine 3 was full characterized by IR, 1D, and 2D NMR spectroscopy, mass spectrometry, and elemental analysis.
Performance Evaluation of Warm Asphalt Mixtures Containing Chemical Additive and Effect of Incorporating High Reclaimed Asphalt Content
Authors: Rathore Mukul , Haritonovs Viktors , Zaumanis Martins
Published: July 2021

Reclaimed asphalt (RA) and Warm mix asphalt (WMA) are two widely used environmentally friendly mixtures in the paving industry. This study compares the laboratory performance of conventional hot mix asphalt (HMA) with virgin WMA, and WMA containing 60% RA content, using thermal stress restrained specimen test, wheel tracking test, and indirect tensile strength test. Based on test results, a reduction of 15 °C in mixing temperature was achieved for WMA mixtures compared to HMA using the given chemical additive. The virgin WMA mixture showed superior cracking resistance but lower rutting resistance than HMA, and incorporation of RA material without any further modification in the binder, deteriorated both cracking and rutting performance of WMA. It was also shown that laboratory short-term aging can significantly affect the performance of the mixtures.
Properties of Metallic and Oxide Thin Films Based on Ti and Co Prepared by Magnetron Sputtering from Sintered Targets with Different Co-Content
Authors: Wojcieszak Damian , Mazur Michał , Pokora Patrycja , Wrona Adriana , Bilewska Katarzyna , Kijaszek Wojciech , Kotwica Tomasz , Posadowski Witold , Domaradzki Jarosław
Published: July 2021

In this work, selected properties of metallic and oxide thin films based on titanium and cobalt were described. Thin-film coatings were prepared using the magnetron sputtering method. The deposition was carried out from sintered targets with different Co-content (2 at.%, 12 at.% and 50 at.%). The relation between the Ti–Co target composition and the Co-content in the metallic and oxide films was examined. There was 15–20% more cobalt in the films than in the target. Moreover, the deposition rate under neutral conditions (in Ar plasma) was even 10-times higher compared to oxidizing Ar:O2 (70:30) plasma. A comprehensive analysis of the structural properties (performed with GIXRD and SEM) revealed the amorphous nature of (Ti,Co)Ox coatings, regardless of the cobalt content in the coating. The fine-grained, homogenous microstructure was observed, where cracks and voids were identified only for films with high Co-content. Optical studies have shown that these films were well transparent (60% ÷ 80%), and the amount of cobalt in the target from which they were sputtered had a significant impact on the decrease in the transparency level, the slight shift of the absorption edge position (from 279 nm to 289 nm) as well as the decrease in their optical band gap energy (from 3.13 eV to 1.71 eV). Electrical studies have shown that in (Ti,Co)Ox thin films, a unipolar memristive-like effect can be observed. The occurrence of such effects has not been reported so far in the case of TiO2 coatings with the addition of Co.
Development of a Caramel-Based Viscoelastic Reference Material for Cutting Tests at Different Rates
Authors: Schab Dennis , Zahn Susann , Rohm Harald
Published: July 2021

Cutting speed plays a crucial role for the behavior during and the final quality of viscoelastic foods after cutting and is, in industrial applications, usually adjusted on an empirical basis. Although previous studies investigated the interplay between the time-dependent properties and cutting behavior of model systems on an elastomer basis, there is still a need to elaborate such cause-effect relations for real foods. The aim of this study was to establish a reproducible manufacture of model caramels on a laboratory scale and to investigate the influence of the compositional parameters, moisture, and solid fat content, as well as cutting speed, on cutting behavior. It was possible to visualize ductile-brittle transitions in cutting force profiles, with an increase in cutting speed resulting in effects similar to that induced by a decreasing moisture content or an increasing solid fat content. Quantitatively, the progression of both maximum force and cutting energy reversed when cutting speed increased and composition changed in favor of a more brittle behavior. This work provides the basis for further research on distinct loading phenomena observed during the cutting of foods and for numerical modeling of the cutting process.
L-Fuzzy Sub-Effect Algebras
Authors: Dong Yan-Yan , Shi Fu-Gui
Published: July 2021

In this paper, the notions of L-fuzzy subalgebra degree and L-subalgebras on an effect algebra are introduced and some characterizations are given. We use four kinds of cut sets of L-subsets to characterize the L-fuzzy subalgebra degree. We induce an L-fuzzy convexity by the L-fuzzy subalgebra degree, and we prove that a morphism between two effect algebras is an L-fuzzy convexity preserving mapping and a monomorphism is an L-fuzzy convex-to-convex mapping. Finally, it is proved that the set of all L-subalgebras on an effect algebra can form an L-convexity, and its L-convex hull formula is given.
Efficiency of Commercial Banking in Developing Countries
Authors: Cvetkoska Violeta , Fotova Čiković Katerina , Tasheva Marija
Published: July 2021

The aim of this paper is to evaluate the relative efficiency of commercial banks in three developing countries in Europe (North Macedonia, Serbia, and Croatia) in the period from 2015 to 2019, and to provide targets for improvement for the inefficient banks by using DEA. The variables are selected under the income-based approach. Based on the output-oriented BCC model, unusual results are obtained for a few commercial banks in each country, that is, they are BCC relative efficient, which is contrary to the real situation. In order to identify outliers that can affect the efficiency results, a super-efficiency procedure is applied so that banks with a super-efficiency score higher than 1.2 (outliers) or for which a feasible solution was not found are considered in detail and removed, and then the output-oriented BCC model is rerun. Based on the obtained results, the Macedonian commercial banking system shows the highest efficiency (91.1%), followed by the Croatian (90.9%) and the Serbian (81.9%) banking system. The estimated targets for improvement of the inefficient commercial banks could help their top bank management in better resource allocation and making fact-based and faster decisions by which they can improve the operation of the banks they lead and contribute to the stability of the financial system.
Solution of Exterior Quasilinear Problems Using Elliptical Arc Artificial Boundary
Authors: Chen Yajun , Du Qikui
Published: July 2021

In this paper, the method of artificial boundary conditions for exterior quasilinear problems in concave angle domains is investigated. Based on the Kirchhoff transformation, the exact quasiliner elliptical arc artificial boundary condition is derived. Using the approximate elliptical arc artificial boundary condition, the finite element method is formulated in a bounded region. The error estimates are obtained. The effectiveness of our method is showed by some numerical experiments.
On the Hardness of Lying under Egalitarian Social Welfare
Authors: Carrero Jonathan , Rodríguez Ismael , Rubio Fernando
Published: July 2021

When it comes to distributing resources among different agents, there are different objectives that can be maximized. In the case of egalitarian social welfare, the goal is to maximize the utility of the least satisfied agent. Unfortunately, this goal can lead to strategic behaviors on the part of the agents: if they lie about their utility functions, then the dealer might grant them more goods than they would be entitled to. In this work, we study the computational complexity of obtaining the optimal lie in this context. We show that although it is extremely easy to obtain the optimal lie when we do not impose any restrictions on the lies used, the problem becomes Σ2P-complete by imposing simple limits on the usable lies. Thus, we prove that we can easily make it hard to lie in the context of egalitarian social welfare.
Efficient Evaluation of Matrix Polynomials beyond the Paterson–Stockmeyer Method
Authors: Sastre Jorge , Ibáñez Javier
Published: July 2021

Recently, two general methods for evaluating matrix polynomials requiring one matrix product less than the Paterson–Stockmeyer method were proposed, where the cost of evaluating a matrix polynomial is given asymptotically by the total number of matrix product evaluations. An analysis of the stability of those methods was given and the methods have been applied to Taylor-based implementations for computing the exponential, the cosine and the hyperbolic tangent matrix functions. Moreover, a particular example for the evaluation of the matrix exponential Taylor approximation of degree 15 requiring four matrix products was given, whereas the maximum polynomial degree available using Paterson–Stockmeyer method with four matrix products is 9. Based on this example, a new family of methods for evaluating matrix polynomials more efficiently than the Paterson–Stockmeyer method was proposed, having the potential to achieve a much higher efficiency, i.e., requiring less matrix products for evaluating a matrix polynomial of certain degree, or increasing the available degree for the same cost. However, the difficulty of these family of methods lies in the calculation of the coefficients involved for the evaluation of general matrix polynomials and approximations. In this paper, we provide a general matrix polynomial evaluation method for evaluating matrix polynomials requiring two matrix products less than the Paterson-Stockmeyer method for degrees higher than 30. Moreover, we provide general methods for evaluating matrix polynomial approximations of degrees 15 and 21 with four and five matrix product evaluations, respectively, whereas the maximum available degrees for the same cost with the Paterson–Stockmeyer method are 9 and 12, respectively. Finally, practical examples for evaluating Taylor approximations of the matrix cosine and the matrix logarithm accurately and efficiently with these new methods are given.
Analysis and Evaluation of Barriers Influencing Blockchain Implementation in Moroccan Sustainable Supply Chain Management: An Integrated IFAHP-DEMATEL Framework
Authors: Boutkhoum Omar , Hanine Mohamed , Nabil Mohamed , El Barakaz Fatima , Lee Ernesto , Rustam Furqan , Ashraf Imran
Published: July 2021

Blockchain technology has received wide attention during recent years, and has huge potential to transform and improve supply chain management. However, its implementation in the SSCM (Sustainable Supply Chain Management) strategy is sophisticated, and the challenges are not explored very well, especially in the Moroccan context. To this end, the chief objective of the current endeavor is to investigate the barriers that hinder the adoption of blockchain technology in SSCM from the Moroccan industry and service sectors’ perspective. Based on a comprehensive literature search and the use of experts’ viewpoints, the barriers affecting the successful implementation of blockchain are classified into three categories called TEO: technological and system, environmental, and intra-organizational dimensions. In this context, a fuzzy group decision-making framework is organized by combining DEMATEL (Decision-Making Trial and Evaluation Laboratory) and IFAHP (Intuitionistic Fuzzy Analytic Hierarchy Process). The IFAHP technique helps to determine the importance/priorities of barriers affecting blockchain adoption, while the DEMATEL technique forms the cause–effect interconnections between these barriers and classifies them concerning the degree of importance and relationships. The results reveal that ‘government policy and support’ and ‘challenges in integrating sustainable practices and blockchain technology through SCM’ are significant adoption barriers of blockchain in Moroccan SSCM. The proposed solution can support industrial decision makers to form flexible short- and long-term decision-making strategies to efficiently manage a sustainable supply chain.
Implementation of Mobile Learning in Mathematics Instruction for Elementary Second Graders
Authors: Wang Tzu-Hua , Kao Chien-Hui , Wang Tsai-Ju
Published: July 2021

In this study, a mobile learning system (MLS) was developed and adopted to facilitate elementary second-grade students to learn mathematics. A quasi-experimental design was adopted. There were two learning models, including the typical instruction group (TI group) and MLS group. The learning content is the topic of multiplication. A total of 93 s-grade students from four classes in a public elementary school in Northern Taiwan participated in this research. Participants were randomly divided into the MLS group (47 participants: 22 boys and 25 girls) and the TI group (46 participants: 26 boys and 20 girls). Participants in the MLS group received mathematics instruction in the MLS, whereas those in the TI group received direct instruction in typical classrooms. All students took the pretest and posttest of mathematics learning achievement test and mathematics learning interest scale assess their improvement of learning achievement and learning interest after the learning activities. The findings revealed that students in the MLS group had significantly better improvement in their mathematics learning interest and mathematics learning achievement than those in the TI group. In addition, students in the MLS group had significantly better performance in answering items of comprehension and application levels in the mathematics learning achievement test.
The Changes in Expression of NaV1.7 and NaV1.8 and the Effects of the Inhalation of Their Blockers in Healthy and Ovalbumin-Sensitized Guinea Pig Airways
Authors: Kocmalova Michaela , Kazimierova Ivana , Barborikova Jana , Joskova Marta , Franova Sona , Sutovska Martina
Published: July 2021

Background: The presented study evaluated the suppositional changes in the airway expression of Nav1.8 and Nav1.7 and their role in the airway defense mechanisms in healthy animals and in an experimental asthma model. Methods: The effects of the blockers inhalation on the reactivity of guinea pig airways, number of citric-acid-induced coughs and ciliary beating frequency (CBF) were tested in vivo. Chronic inflammation simulating asthma was induced by repetitive exposure to ovalbumin. The expression of Nav1.7 and Nav1.8 was examined by ELISA. Results: The Nav 1.8 blocker showed complex antitussive and bronchodilatory effects and significantly regulated the CBF in healthy and sensitized animals. The Nav1.7 blockers significantly inhibited coughing and participated in CBF control in the ovalbumin-sensitized animals. The increased expression of the respective ion channels in the sensitized animals corresponded to changes in CBF regulation. The therapeutic potency of the Nav1.8 blocker was evidenced in combinations with classic bronchodilators. Conclusion: The allergic-inflammation-upregulated expression of Nav1.7 and Nav1.8 and corresponding effects of blocker inhalation on airway defense mechanisms, along with the Nav1.8 blocker’s compatibility with classic antiasthmatic drugs, bring novel possibilities for the treatment of various respiratory diseases. However, the influence of the Nav1.8 blocker on CBF requires further investigation.
Research Progress in Computational Fluid Dynamics Simulations of Membrane Distillation Processes: A Review
Authors: Chen Long , Wu Binxin
Published: July 2021

Membrane distillation (MD) can be used in drinking water treatment, such as seawater desalination, ultra-pure water production, chemical substances concentration, removal or recovery of volatile solutes in an aqueous solution, concentration of fruit juice or liquid food, and wastewater treatment. However, there is still much work to do to determine appropriate industrial implementation. MD processes refer to thermally driven transport of vapor through non-wetted porous hydrophobic membranes, which use the vapor pressure difference between the two sides of the membrane pores as the driving force. Recently, computational fluid dynamics (CFD) simulation has been widely used in MD process analysis, such as MD mechanism and characteristics analysis, membrane module development, preparing novel membranes, etc. A series of related research results have been achieved, including the solutions of temperature/concentration polarization and permeate flux enhancement. In this article, the research of CFD applications in MD progress is reviewed, including the applications of CFD in the mechanism and characteristics analysis of different MD structures, in the design and optimization of membrane modules, and in the preparation and characteristics analysis of novel membranes. The physical phenomena and geometric structures have been greatly simplified in most CFD simulations of MD processes, so there still is much work to do in this field in the future. A great deal of attention has been paid to the hydrodynamics and heat transfer in the channels of MD modules, as well as the optimization of these modules. However, the study of momentum transfer, heat, and mass transfer mechanisms in membrane pores is rarely involved. These projects should be combined with mass transfer, heat transfer and momentum transfer for more comprehensive and in-depth research. In most CFD simulations of MD processes, some physical phenomena, such as surface diffusion, which occur on the membrane surface and have an important guiding significance for the preparation of novel membranes to be further studied, are also ignored. As a result, although CFD simulation has been widely used in MD process modeling already, there are still some problems remaining, which should be studied in the future. It can be predicted that more complex mechanisms, such as permeable wall conditions, fouling dynamics, and multiple ionic component diffusion, will be included in the CFD modeling of MD processes. Furthermore, users’ developed routines for MD processes will also be incorporated into the existing commercial or open source CFD software packages.
Parameter Optimization of Hybrid-Tandem Gas Metal Arc Welding Using Analysis of Variance-Based Gaussian Process Regression
Authors: Kim Jin Young , Lee Dae Young , Lee Jaeyoung , Lee Seung Hwan
Published: July 2021

In this paper, the parameter optimization of the hybrid-tandem gas metal arc welding (GMAW) process was studied. The hybrid-tandem GMAW process uses an additional filler-wire with opposite polarity in contrast to the conventional tandem process. In this process, more process parameters and the relationship between the parameters causing strong nonlinearity should be considered. The analysis of variance-based Gaussian process regression (ANOVA-GPR) method was implemented to construct surrogate modeling, which can express nonlinearity including uncertainty of weld quality. Major parameters among several process parameters in this welding process can be extracted by use of this novel method. The weld quality used as a cost function in the optimization of process parameters is defined by characteristics related to penetration and bead shape, and the sequential quadratic programming (SQP) method was used to determine the optimal welding condition. This approach enabled sound weld quality at a high travel speed of 1.9 m/min, which is difficult to achieve in the hybrid-tandem GMAW process.
Power Density Improvement of Piezoelectric Energy Harvesters via a Novel Hybridization Scheme with Electromagnetic Transduction
Authors: Li Zhongjie , Xin Chuanfu , Peng Yan , Wang Min , Luo Jun , Xie Shaorong , Pu Huayan
Published: July 2021

A novel hybridization scheme is proposed with electromagnetic transduction to improve the power density of piezoelectric energy harvester (PEH) in this paper. Based on the basic cantilever piezoelectric energy harvester (BC-PEH) composed of a mass block, a piezoelectric patch, and a cantilever beam, we replaced the mass block by a magnet array and added a coil array to form the hybrid energy harvester. To enhance the output power of the electromagnetic energy harvester (EMEH), we utilized an alternating magnet array. Then, to compare the power density of the hybrid harvester and BC-PEH, the experiments of output power were conducted. According to the experimental results, the power densities of the hybrid harvester and BC-PEH are, respectively, 3.53 mW/cm3 and 5.14 μW/cm3 under the conditions of 18.6 Hz and 0.3 g. Therefore, the power density of the hybrid harvester is 686 times as high as that of the BC-PEH, which verified the power density improvement of PEH via a hybridization scheme with EMEH. Additionally, the hybrid harvester exhibits better performance for charging capacitors, such as charging a 2.2 mF capacitor to 8 V within 17 s. It is of great significance to further develop self-powered devices.
Femtosecond Laser Engraving of Deep Patterns in Steel and Sapphire
Authors: Pallarés-Aldeiturriaga David , Claudel Pierre , Granier Julien , Travers Julien , Guillermin Lionel , Flaissier Marc-Olivier , d’Augeres Patrick Beaure , Sedao Xxx
Published: July 2021

Femtosecond laser engraving offers appealing advantages compared to regular laser engraving such as higher precision and versatility. In particular, the inscription of deep patterns exhibits an increasing interest in industry. In this work, an optimization protocol based on constraining overlap ratio and scan number is demonstrated. The proposed method allows changing overlap ratio while maintaining depth in the same range, which reduces the sampling number. This study WAS applied to stainless steel 316 L and sapphire for engravings deeper than 100 μm. Results exhibit overall depths higher than threshold values and allowed to determine optimized engraving quality, for instance, roughness in steel can be reduced while maintaining depth and taper angle by reducing overlap ratio. The optimized laser parameters such as roughness and taper angle factors for sapphire were also found to be as follows: 200 kHz, 86% overlap and 12 J/cm2. As a demonstration, a logo engraving is illustrated at the end.
Flexible Enzymatic Glucose Electrochemical Sensor Based on Polystyrene-Gold Electrodes
Authors: Müsse Annika , La Malfa Francesco , Brunetti Virgilio , Rizzi Francesco , De Vittorio Massimo
Published: July 2021

Metabolic disorders such as the highly prevalent disease diabetes require constant monitoring. The health status of patients is linked to glucose levels in blood, which are typically measured invasively, but can also be correlated to other body fluids such as sweat. Aiming at a reliable glucose biosensor, an enzymatic sensing layer was fabricated on flexible polystyrene foil, for which a versatile nanoimprinting process for microfluidics was presented. For the sensing layer, a gold electrode was modified with a cysteine layer and glutaraldehyde cross-linker for enzyme conformal immobilization. Chronoamperometric measurements were conducted in PBS buffered glucose solution at two potentials (0.65 V and 0.7 V) and demonstrated a linear range between 0.025 mM to 2mM and an operational range of 0.025 mM to 25 mM. The sensitivity was calculated as 1.76µA/mM/cm2 and the limit of detection (LOD) was calculated as 0.055 mM at 0.7 V. An apparent Michaelis–Menten constant of 3.34 mM (0.7 V) and 0.445 mM (0.65 V) was computed. The wide operational range allows the application for point-of-care testing for a variety of body fluids. Yet, the linear range and low LOD make this biosensor especially suitable for non-invasive sweat sensing wearables.
Indicative Marker Microbiome Structures Deduced from the Taxonomic Inventory of 67 Full-Scale Anaerobic Digesters of 49 Agricultural Biogas Plants
Authors: Hassa Julia , Klang Johanna , Benndorf Dirk , Pohl Marcel , Hülsemann Benedikt , Mächtig Torsten , Effenberger Mathias , Pühler Alfred , Schlüter Andreas , Theuerl Susanne
Published: July 2021

There are almost 9500 biogas plants in Germany, which are predominantly operated with energy crops and residues from livestock husbandry over the last two decades. In the future, biogas plants must be enabled to use a much broader range of input materials in a flexible and demand-oriented manner. Hence, the microbial communities will be exposed to frequently varying process conditions, while an overall stable process must be ensured. To accompany this transition, there is the need to better understand how biogas microbiomes respond to management measures and how these responses affect the process efficiency. Therefore, 67 microbiomes originating from 49 agricultural, full-scale biogas plants were taxonomically investigated by 16S rRNA gene amplicon sequencing. These microbiomes were separated into three distinct clusters and one group of outliers, which are characterized by a specific distribution of 253 indicative taxa and their relative abundances. These indicative taxa seem to be adapted to specific process conditions which result from a different biogas plant operation. Based on these results, it seems to be possible to deduce/assess the general process condition of a biogas digester based solely on the microbiome structure, in particular on the distribution of specific indicative taxa, and without knowing the corresponding operational and chemical process parameters. Perspectively, this could allow the development of detection systems and advanced process models considering the microbial diversity.