bluuebunny/crossref_metadata_2025 huggingface dataset:
Korean Children’s Attitudes toward Varieties of English: The Role of Age and English Learning Environment
Authors: Choi Naya , Cho Hye-Jung , Kang Sujeong , Ahn Hyejeong
Published: August 2021

This study investigates young Korean children’s attitudes toward three English varieties: American English (AmE), Singapore English (SiE), and Korean English (KoE). A total of 42 Korean children participated in this study. For data analysis purposes, the results were categorized according to the children’s age and their experience of exposure to formal English learning. In addition to this, 30 Singaporean children were also involved in the study, and their results were compared with the results of the younger group of Korean children. A mixed methodological approach, which included a modified verbal guise technique appropriate for use with children and semi-structured interviews, was also adopted. The results show that 5-year-old Korean and Singaporean children do not prefer one specific variety of English more than the other varieties of English. However, this was not the case for 12-year-old Korean children. These older Korean children preferred AmE and SiE more than KoE, and the “speaker’s pronunciation” was considered to be the critical feature in determining these attitudes. The findings suggest that Korean children’s developing attitudes toward a particular variety of English emerge sometime during their elementary school years.
2-Hydroxy-3-octyloxybenzaldehyde
Authors: Novoselova Julia V. , Vereshchagin Anatoliy A. , Kalnin Arseniy Y. , Lukyanov Daniil A. , Levin Oleg V.
Published: August 2021

Herein, we report the chromatography-free synthesis of 2-hydroxy-3-octyloxybenzaldehyde by the alkylation of 2,3-dihydroxybenzaldehyde as a promising precursor for new SalEn-type complexes with transition metals. The structure of the product is elucidated by means of 1H and 13C-NMR spectra, high-resolution mass spectrometry with electrospray ionization (ESI-HRMS) and Fourier-transform infrared spectroscopy (FTIR).
Low-Computational-Cost Technique for Modeling Macro Fiber Composite Piezoelectric Actuators Using Finite Element Method
Authors: Emad Diaa , Fanni Mohamed A. , Mohamed Abdelfatah M. , Yoshida Shigeo
Published: August 2021

The large number of interdigitated electrodes (IDEs) in a macro fiber composite (MFC) piezoelectric actuator dictates using a very fine finite element (FE) mesh that requires extremely large computational costs, especially with a large number of actuators. The situation becomes infeasible if repeated finite element simulations are required, as in control tasks. In this paper, an efficient technique is proposed for modeling MFC using a finite element method. The proposed technique replaces the MFC actuator with an equivalent simple monolithic piezoceramic actuator using two electrodes only, which dramatically reduces the computational costs. The proposed technique was proven theoretically since it generates the same electric field, strain, and displacement as the physical MFC. Then, it was validated with the detailed FE model using the actual number of IDEs, as well as with experimental tests using triaxial rosette strain gauges. The computational costs for the simplified model compared with the detailed model were dramatically reduced by about 74% for memory usage, 99% for result file size, and 98.6% for computational time. Furthermore, the experimental results successfully verified the proposed technique with good consistency. To show the effectiveness of the proposed technique, it was used to simulate a morphing wing covered almost entirely by MFCs with low computational cost.
Modeling of Thermo-Chemo-Mechanical Properties of Anode Mixture during the Baking Process
Authors: Chen Bowen , Chaouki Hicham , Picard Donald , Lauzon-Gauthier Julien , Alamdari Houshang , Fafard Mario
Published: August 2021

In the Hall–Héroult process, prebaked carbon anodes are utilized to produce primary aluminium. The quality of the anode plays a crucial role in the efficiency of electrowinning primary aluminium. In the production of anodes, the anode baking is considered as the stage most frequently causing anode problems. During the baking process, the anode undergoes complex physicochemical transformations. Moreover, the anode at a lower position, imposed by loading pressures from upper anodes, will creep during this process. Thus, the production of high-quality anodes demands efficient control of their baking process. This paper aims to investigate the thermo-chemo-mechanical properties of the anode paste mixture at high temperatures. These properties include kinetic parameters of pitch pyrolysis such as the activation energy and the pre-exponential factor, the thermal expansion coefficient (TEC) and relevant mechanical parameters related to the elastic, the viscoelastic and the viscoplastic behaviours of the anode. For this purpose, experiments consisting of the thermogravimetric analysis, the dilatometry and the creep test were carried out. Based on the obtained results, the forementioned parameters were identified. Relevant mechanical parameters were expressed as a function of a new variable, called the shrinking index, which is related to the volatile released in open and closed pores of the anode. This variable would be used to highlight the chemo-mechanical coupling effect of the anode mixture. New insights into the phenomena such as the expansion due to the increase of the pore pressure and the chemical shrinkage of the anode during the baking process were also gained in this work. These investigations pave the way for modeling the thermo-chemo-poromechanical behaviour of the anode during the baking process.
Analysis of Micro-Machining Process for External Thread of Micro Round Tube
Authors: Chen Tsung-Chia , Lian Jyun-Jie , Wang Cheng-Chi
Published: August 2021

This study aims to analyze the stainless steel micro round tube external threading process for the influence of different outer threading pitches (0.25 mm, 0.4 mm) and outer diameters (Ø1.9, Ø1.94, Ø2). This study also analyzes the effects of different friction factors (0.1, 0.3, 0.5, 0.7, and 0.9) and different tube thicknesses (0.4, 0.45, 0.5, 0.55, and 0.6 mm) on the threading process. This study considers size effect to use corrected material parameters for the microtube to conduct the finite element analysis by DEFORM-3D software. The goal is to understand stainless steel (SUS304) micro round tube threading and the difference by using macro material parameter analysis. The historic forming data from the simulation and experiment of threading processing are presented, and the corresponding stress/strain distribution and thread shape are also calculated. The experiment results are compared to the simulation results to verify the reliability of this analysis method. The result shows that the torque/stress/strain obtained by the modified model is always lower than by Swift’s model. It means that the size effect can be considered to apply on the forming process and provided proper torque to form the external thread of the micro round tube, e.g., the maximum torque of the round die for M2 × 0.25 occurs over the fourth stroke. For the influence of the outer diameter of the micro round tube, the larger diameter induces the larger maximum torque on the round die for M2 × 0.4, but for the smaller pitch of M2 × 0.25, the larger maximum torque is not influenced by the diameter of the tube. When the pitch of the round die is increased, the torque, stress and strain are also increased relatively. As the friction factor and torque between the round die and tube increase, the stress and strain become lower. Changing the tube thickness will not significantly change the torque, the stress, and the strain. These results guide the simulation and experiment of optimized micro round tube threading development and design to reduce cost and increase product quality.
Effect of Hemp Fiber Surface Treatment on the Moisture/Water Resistance and Reaction to Fire of Reinforced PLA Composites
Authors: Alao Percy Festus , Marrot Laetitia , Kallakas Heikko , Just Alar , Poltimäe Triinu , Kers Jaan
Published: August 2021

The effects of surface pretreatment (water and alkali) and modification with silane on moisture sorption, water resistance, and reaction to fire of hemp fiber reinforced polylactic acid (PLA) composites at two fiber loading contents (30 and 50 wt.%) are investigated in this work. Moisture adsorption was evaluated at 30, 50, 75 and 95% relative humidity, and water resistance was determined after a 28-day immersion period. The cone calorimetry technique was used to investigate response to fire. The fiber surface treatment resulted in the removal of cell wall components, which increased fiber individualization and homogeneity as shown in scanning microscopic pictures of the composite cross-section. Although the improved fiber/matrix bonding increased the composite’s water resistance, the different fiber treatments generated equal moisture adsorption results for the 30 wt.% reinforced composites. Overall, increasing the fiber amount from 30 to 50 wt.% increased the composite sensitivity to moisture/water, mainly due to the availability of more hydroxyl groups and to the development of a higher pore volume, but fire protection improved due to a reduction in the rate of thermal degradation induced by the reduced PLA content. The new Oswin’s model predicted the composite adsorption isotherm well. The 30 wt.% alkali and silane treated hemp fiber composite had the lowest overall adsorption (9%) while the 50 wt.% variant produced the highest ignition temperature (181 ± 18 °C).
Modeling of Compressive Strength of Self-Compacting Rubberized Concrete Using Machine Learning
Authors: Kovačević Miljan , Lozančić Silva , Nyarko Emmanuel Karlo , Hadzima-Nyarko Marijana
Published: August 2021

This paper gives a comprehensive overview of the state-of-the-art machine learning methods that can be used for estimating self-compacting rubberized concrete (SCRC) compressive strength, including multilayered perceptron artificial neural network (MLP-ANN), ensembles of MLP-ANNs, regression tree ensembles (random forests, boosted and bagged regression trees), support vector regression (SVR) and Gaussian process regression (GPR). As a basis for the development of the forecast model, a database was obtained from an experimental study containing a total of 166 samples of SCRC. Ensembles of MLP-ANNs showed the best performance in forecasting with a mean absolute error (MAE) of 2.81 MPa and Pearson’s linear correlation coefficient (R) of 0.96. The significantly simpler GPR model had almost the same accuracy criterion values as the most accurate model; furthermore, feature reduction is easy to combine with GPR using automatic relevance determination (ARD), leading to models with better performance and lower complexity.
Study of Corrosion, Structural, and Mechanical Properties of EN AW-6082 and EN AW-7075 Welded Joints
Authors: Wojdat Tomasz , Kustroń Paweł , Jaśkiewicz Karol , Pabian Jarosław
Published: August 2021

The purpose of the work was to test the welded joints of aluminum alloys EN AW-7075 and EN AW-6082, which are used to join individual structural elements of car bodies, e.g., B-pillar with the body. The joints were made using the low-energy cold metal transfer (CMT) arc welding method. The results of the structure investigations of lap and butt joints, as well as tests of mechanical properties are presented. The influence of linear energy and the way of arranging materials in lap joints on the possibility of hot cracks occurrence has been demonstrated. The shear strength of lap joints was equal to 150 MPa, while the tensile strength of butt joints was equal to 375 MPa. The highest hardness reduction was observed in the heat affected zone (HAZ) from the EN AW-7075 alloy side in the range of 98 to 138 HV 0.05. In addition, a significant reduction of the corrosion resistance in the transition zone between HAZ and the base material (EN AW-7075 alloy) in the medium salinity environment, corresponding to the sea conditions according to ASTM G85 was indicated.
Self-Sensing Properties of Fly Ash Geopolymer Doped with Carbon Black under Compression
Authors: Mizerová Cecílie , Kusák Ivo , Topolář Libor , Schmid Pavel , Rovnaník Pavel
Published: August 2021

The development of smart materials is a basic prerequisite for the development of new technologies enabling the continuous non-destructive diagnostic analysis of building structures. Within this framework, the piezoresistive behavior of fly ash geopolymer with added carbon black under compression was studied. Prepared cubic specimens were doped with 0.5, 1 and 2% carbon black and embedded with four copper electrodes. In order to obtain a complex characterization during compressive loading, the electrical resistivity, longitudinal strain and acoustic emission were recorded. The samples were tested in two modes: repeated loading under low compressive forces and continuous loading until failure. The results revealed piezoresistivity for all tested mixtures, but the best self-sensing properties were achieved with 0.5% of carbon black admixture. The complex analysis also showed that fly ash geopolymer undergoes permanent deformations and the addition of carbon black changes its character from quasi-brittle to rather ductile. The combination of electrical and acoustic methods enables the monitoring of materials far beyond the working range of a strain gauge.
Insights in the Ionic Conduction inside Nanoporous Metal-Organic Frameworks by Using an Appropriate Equivalent Circuit
Authors: Chandresh Abhinav , Zhang Zejun , Heinke Lars
Published: August 2021

The conduction of protons and other ions in nanoporous materials, such as metal-organic frameworks (MOFs), is intensively explored with the aim of enhancing the performance of energy-related electrochemical systems. The ionic conductivity, as a key property of the material, is typically determined by using electrochemical impedance spectroscopy (EIS) in connection with a suitable equivalent circuit. Often, equivalent circuits are used where the physical meaning of each component is debatable. Here, we present an equivalent circuit for the ionic conduction of electrolytes in nanoporous, nonconducting materials between inert and impermeable electrodes without faradaic electrode reactions. We show the equivalent circuit perfectly describes the impedance spectra measured for the ion conduction in MOFs in the form of powders pressed into pellets as well as for MOF thin films. This is demonstrated for the ionic conduction of an aprotic ionic liquid, and of various protic solvents in different MOF structures. Due to the clear physical meaning of each element of the equivalent circuit, further insights into the electrical double layer forming at the MOF-electrode interface can be obtained. As a result, EIS combined with the appropriate reference circuit allows us to make statements of the quality of the MOF-substrate interface of different MOF-film samples.
Key Factors for Implementing Magnetic NDT Method on Thin UHPFRC Bridge Elements
Authors: Nunes Sandra , Pimentel Mário , Sine Aurélio , Mokhberdoran Paria
Published: August 2021

This paper provides an overview of the use of the magnetic NDT method for estimating the fibre content, and fibre orientation and efficiency factors in thin UHPFRC elements/layers, along any two orthogonal directions. These parameters are of utmost importance for predicting the post-cracking tensile strength in the directions of interest. After establishing meaningful correlations at the lab-specimen scale, this NDT method can be effectively implemented into quality control protocols at the industrial production scale. The current study critically addresses the influence of key factors associated with using this NDT method in practice and provides recommendations for its efficient implementation.
Bond Behaviour of Near-Surface Mounted Strips in RC Beams—Experimental Investigation and Numerical Simulations
Authors: Kotynia Renata , Baky Hussien Abdel , Neale Kenneth W.
Published: August 2021

This paper presents an investigation of the bond mechanism between carbon fibre reinforced polymer (CFRP) laminates, concrete and steel in the near-surface mounted (NSM) CFRP-strengthened reinforced concrete (RC) beam-bond tests. The experimental program consisting of thirty modified concrete beams flexurally strengthened with NSM CFRP strips was published in. The effects of five parameters and their interactions on the ultimate load carrying capacities and the associated bond mechanisms of the beams are investigated in this paper with consideration of the following investigated parameters: beam span, beam depth, longitudinal tensile steel reinforcement ratio, the bond length of the CFRP strips and compressive concrete strength. The longitudinal steel reinforcement was cut at the beam mid-span in four beams to investigate a better assessment of the influence of the steel reinforcement ratio on the bond behaviour of CFRP to concrete bond behaviour. The numerical analysis implemented in this paper is based on a nonlinear micromechanical finite element model (FEM) that was used for investigation of the flexural behaviour of NSM CFRP-strengthened members. The 3D model based on advanced CFRP to concrete bond responses was introduced to modelling of tested specimens. The FEM procedure presents the orthotropic behaviour of the CFRP strips and the bond response between the CFRP and concrete. Comparison of the experimental and numerical results revealed an excellent agreement that confirms the suitability of the proposed FE model.
Iterative Parameter Optimization for Multiple Switching Control Applied to a Precision Stage for Microfabrication
Authors: Wang Fu-Cheng , Lu Jun-Fu , Chung Tien-Tung , Yen Jia-Yush
Published: August 2021

This paper proposes an iteration procedure to derive optimal parameters for a multiple switching control architecture. Control design is usually a compromise between various performance requirements; therefore, switching between multiple controllers that achieve a particular performance under different conditions can potentially improve the overall system behavior. In this paper, we consider a control-switching mechanism that can automatically switch controllers based on the prediction of future responses, and we develop an iteration procedure that can optimize the mechanism parameters, such as the number of controllers and the prediction horizon. We then implement the proposed mechanism in a long-stroke precision stage, and demonstrate the effectiveness of switching robust control with simulations and experiments. Lastly, we integrate the stage with a two-photon polymerization system to fabricate microlenses. The optical properties confirm that the proposed iterative parameter optimization procedure is effective in improving the performance of microfabrication employing multiple switching control.
A Functional Characterization of Almost Greedy and Partially Greedy Bases in Banach Spaces
Authors: Berná Pablo Manuel , Mondéjar Diego
Published: August 2021

In 2003, S. J. Dilworth, N. J. Kalton, D. Kutzarova and V. N. Temlyakov introduced the notion of almost greedy (respectively partially greedy) bases. These bases were characterized in terms of quasi-greediness and democracy (respectively conservativeness). In this paper, we show a new functional characterization of these type of bases in general Banach spaces following the spirit of the characterization of greediness proved in 2017 by P. M. Berná and Ó. Blasco.
On the Theory of Left/Right Almost Groups and Hypergroups with their Relevant Enumerations
Authors: Massouros Christos G. , Yaqoob Naveed
Published: August 2021

This paper presents the study of algebraic structures equipped with the inverted associativity axiom. Initially, the definition of the left and the right almost-groups is introduced and afterwards, the study is focused on the more general structures, which are the left and the right almost-hypergroups and on their enumeration in the cases of order 2 and 3. The outcomes of these enumerations compared with the corresponding in the hypergroups reveal interesting results. Next, fundamental properties of the left and right almost-hypergroups are proved. Subsequently, the almost hypergroups are enriched with more axioms, like the transposition axiom and the weak commutativity. This creates new hypercompositional structures, such as the transposition left/right almost-hypergroups, the left/right almost commutative hypergroups, the join left/right almost hypergroups, etc. The algebraic properties of these new structures are analyzed and studied as well. Especially, the existence of neutral elements leads to the separation of their elements into attractive and non-attractive ones. If the existence of the neutral element is accompanied with the existence of symmetric elements as well, then the fortified transposition left/right almost-hypergroups and the transposition polysymmetrical left/right almost-hypergroups come into being.
Marketing Mix Modeling Using PLS-SEM, Bootstrapping the Model Coefficients
Authors: Méndez-Suárez Mariano
Published: August 2021

Partial least squares structural equations modeling (PLS-SEM) uses sampling bootstrapping to calculate the significance of the model parameter estimates (e.g., path coefficients and outer loadings). However, when data are time series, as in marketing mix modeling, sampling bootstrapping shows inconsistencies that arise because the series has an autocorrelation structure and contains seasonal events, such as Christmas or Black Friday, especially in multichannel retailing, making the significance analysis of the PLS-SEM model unreliable. The alternative proposed in this research uses maximum entropy bootstrapping (meboot), a technique specifically designed for time series, which maintains the autocorrelation structure and preserves the occurrence over time of seasonal events or structural changes that occurred in the original series in the bootstrapped series. The results showed that meboot had superior performance than sampling bootstrapping in terms of the coherence of the bootstrapped data and the quality of the significance analysis.
Recent Developments on the Synthesis and Bioactivity of Ilamycins/Rufomycins and Cyclomarins, Marine Cyclopeptides That Demonstrate Anti-Malaria and Anti-Tuberculosis Activity
Authors: Kazmaier Uli , Junk Lukas
Published: August 2021

Ilamycins/rufomycins and cyclomarins are marine cycloheptapeptides containing unusual amino acids. Produced by Streptomyces sp., these compounds show potent activity against a range of mycobacteria, including multidrug-resistant strains of Mycobacterium tuberculosis. The cyclomarins are also very potent inhibitors of Plasmodium falciparum. Biosynthetically the cyclopeptides are obtained via a heptamodular nonribosomal peptide synthetase (NRPS) that directly incorporates some of the nonproteinogenic amino acids. A wide range of derivatives can be obtained by fermentation, while bioengineering also allows the mutasynthesis of derivatives, especially cyclomarins. Other derivatives are accessible by semisynthesis or total syntheses, reported for both natural product classes. The anti-tuberculosis (anti-TB) activity results from the binding of the peptides to the N-terminal domain (NTD) of the bacterial protease-associated unfoldase ClpC1, causing cell death by the uncontrolled proteolytic activity of this enzyme. Diadenosine triphosphate hydrolase (PfAp3Aase) was found to be the active target of the cyclomarins in Plasmodia. SAR studies with natural and synthetic derivatives on ilamycins/rufomycins and cyclomarins indicate which parts of the molecules can be simplified or otherwise modified without losing activity for either target. This review examines all aspects of the research conducted in the syntheses of these interesting cyclopeptides.
Cognitive Status Epilepticus: Two Case Reports
Authors: Karantali Eleni , Chatzikonstantinou Symela , Mavroudis Ioannis , Trus Constantin , Kazis Dimitrios
Published: August 2021

Cognitive status epilepticus is an uncommon form of focal status epilepticus presenting with a dysfunction of language, thinking or associated higher cortical functions. The absence of ictal manifestations can be misleading and delay a prompt diagnosis. Here we present two patients; one with amnesic and one with aphasic status epilepticus. Through these cases, we aim to highlight the value of EEG performance early in the diagnostic work-up and early antiepileptic drug initiation in cases where an epileptic disorder cannot be excluded.
Phase Transformations upon Ageing in Ti15Mo Alloy Subjected to Two Different Deformation Methods
Authors: Bartha Kristína , Stráský Josef , Veverková Anna , Veselý Jozef , Čížek Jakub , Málek Jaroslav , Polyakova Veronika , Semenova Irina , Janeček Miloš
Published: August 2021

Ti15Mo alloy was subjected to two techniques of intensive plastic deformation, namely high pressure torsion and rotary swaging at room temperature. The imposed strain resulted in the formation of an ultrafine-grained structure in both deformed conditions. Detailed inspection of the microstructure revealed the presence of grains with a size of around 100 nm in both conditions. The microstructure after rotary swaging also contained elongated grains with a length up to 1 µm. Isothermal ageing at 400 °C and 500 °C up to 16 h was applied to both conditions to investigate the kinetics of precipitation of the α phase and the recovery of lattice defects. Positron annihilation spectroscopy indicated that the recovery of lattice defects in the β matrix had already occurred at 400 °C and, in terms of positron trapping, was partly compensated by the precipitation of incoherent α particles. At 500 °C the recovery was fully offset by the formation of incoherent α/β interfaces. Contrary to common coarse-grained material, in which the α phase precipitates in the form of lamellae, precipitation of small and equiaxed α particles occurred in the deformed condition. A refined two-phase equiaxed microstructure with α particles and β grain sizes below 1 μm is achievable by simple rotary swaging followed by ageing.
A Near-Surface Layer Heat Treatment of Die Casting Dies by Means of Electron-Beam Technology
Authors: Schuchardt Torsten , Müller Sebastian , Dilger Klaus
Published: August 2021

Increasing the service life of die casting dies is an important goal of the foundry industry. Approaches are either material- or process-related. Despite new material concepts, hot work steels such as H11 are still predominantly used in the uncoated condition for die casting dies. In order to withstand the stresses that occur, this steel is used exclusively in the quenched and tempered condition. Required properties such as high high-temperature strength and high hardness combined with high toughness are, in principle, contradictory and can only be adjusted consistently over the entire die by furnace-based heat treatment. However, the results of various investigations have shown that improvements in the thermal shock resistance and wear resistance of hot work tool steels can be achieved by thermally influencing the microstructure near the surface. Based on these studies and related findings, an approach to surface heat treatment using the electron beam was developed. Due to the particle character of the radiation and the associated possibility of high-frequency beam deflection, the electron beam offers significantly greater flexibility in energy input into the workpiece surface compared with lasers or induction. The overall technological concept envisages replacing furnace-based heat treatment in the production of casting dies by localized and demand-oriented boundary layer heat treatment with the electron beam. The experiments include, on the one hand, the experimental determination of a suitable temperature–time interval with a focus on short-term austenitization. On the other hand, a simulation-based approach of boundary layer heat treatment with validation of a suitable heat source is investigated. Regarding short-term austenitization, the corresponding temperature and time range could be narrowed down more precisely. Some of these parameter combinations seem to be very suitable for practical use. The test specimens show a hard surface layer with a depth of at least up to 6 mm and a very tough buffer layer. Numerical simulation is used to estimate the resulting metallurgical microstructure and the achievable hardness as a function of the temperature–time interval. In addition, the results provided show the possibility of determining and optimizing the material properties by means of a simulation-based approach within the framework of a purely digital process planning and subsequently transferring them into a process planning. In the technical implementation, a temperature control was first established by means of a two-color pyrometer. In the further course of research, the pyrometer will be supplemented by an internally installed infrared camera, which will allow the reproducible setting of specified temperature profiles even for complex, large-area contours in the future.
TCF19 Impacts a Network of Inflammatory and DNA Damage Response Genes in the Pancreatic β-Cell
Authors: Yang Grace , Fontaine Danielle , Lodh Sukanya , Blumer Joseph , Roopra Avtar , Davis Dawn
Published: August 2021

Transcription factor 19 (TCF19) is a gene associated with type 1 diabetes (T1DM) and type 2 diabetes (T2DM) in genome-wide association studies. Prior studies have demonstrated that Tcf19 knockdown impairs β-cell proliferation and increases apoptosis. However, little is known about its role in diabetes pathogenesis or the effects of TCF19 gain-of-function. The aim of this study was to examine the impact of TCF19 overexpression in INS-1 β-cells and human islets on proliferation and gene expression. With TCF19 overexpression, there was an increase in nucleotide incorporation without any change in cell cycle gene expression, alluding to an alternate process of nucleotide incorporation. Analysis of RNA-seq of TCF19 overexpressing cells revealed increased expression of several DNA damage response (DDR) genes, as well as a tightly linked set of genes involved in viral responses, immune system processes, and inflammation. This connectivity between DNA damage and inflammatory gene expression has not been well studied in the β-cell and suggests a novel role for TCF19 in regulating these pathways. Future studies determining how TCF19 may modulate these pathways can provide potential targets for improving β-cell survival.
Current Review of Optical Neural Interfaces for Clinical Applications
Authors: Park Younghoon , Park Sung-Yun , Eom Kyungsik
Published: August 2021

Neural interfaces, which enable the recording and stimulation of living neurons, have emerged as valuable tools in understanding the brain in health and disease, as well as serving as neural prostheses. While neural interfaces are typically based on electrical transduction, alternative energy modalities have been explored to create safe and effective approaches. Among these approaches, optical methods of linking neurons to the outside world have gained attention because light offers high spatial selectivity and decreased invasiveness. Here, we review the current state-of-art of optical neural interfaces and their clinical applications. Optical neural interfaces can be categorized into optical control and optical readout, each of which can be divided into intrinsic and extrinsic approaches. We discuss the advantages and disadvantages of each of these methods and offer a comparison of relative performance. Future directions, including their clinical opportunities, are discussed with regard to the optical properties of biological tissue.
Fluid Flow Mechanical Stimulation-Assisted Cartridge Device for the Osteogenic Differentiation of Human Mesenchymal Stem Cells
Authors: Lim Ki-Taek , Patel Dinesh-K. , Dutta Sayan-Deb , Ganguly Keya
Published: August 2021

Human mesenchymal stem cells (hMSCs) have the potential to differentiate into different types of mesodermal tissues. In vitro proliferation and differentiation of hMSCs are necessary for bone regeneration in tissue engineering. The present study aimed to design and develop a fluid flow mechanically-assisted cartridge device to enhance the osteogenic differentiation of hMSCs. We used the fluorescence-activated cell-sorting method to analyze the multipotent properties of hMSCs and found that the cultured cells retained their stemness potential. We also evaluated the cell viabilities of the cultured cells via water-soluble tetrazolium salt 1 (WST-1) assay under different rates of flow (0.035, 0.21, and 0.35 mL/min) and static conditions and found that the cell growth rate was approximately 12% higher in the 0.035 mL/min flow condition than the other conditions. Moreover, the cultured cells were healthy and adhered properly to the culture substrate. Enhanced mineralization and alkaline phosphatase activity were also observed under different perfusion conditions compared to the static conditions, indicating that the applied conditions play important roles in the proliferation and differentiation of hMSCs. Furthermore, we determined the expression levels of osteogenesis-related genes, including the runt-related protein 2 (Runx2), collagen type I (Col1), osteopontin (OPN), and osteocalcin (OCN), under various perfusion vis-à-vis static conditions and found that they were significantly affected by the applied conditions. Furthermore, the fluorescence intensities of OCN and OPN osteogenic gene markers were found to be enhanced in the 0.035 mL/min flow condition compared to the control, indicating that it was a suitable condition for osteogenic differentiation. Taken together, the findings of this study reveal that the developed cartridge device promotes the proliferation and differentiation of hMSCs and can potentially be used in the field of tissue engineering.
Novel Blood Clot Retriever for Ischemic Stroke
Authors: Hung Ming-Ya , Yang Chun-Kai , Chen Jiong-Hong , Lin Li-Han , Hsiao Hao-Ming
Published: August 2021

Stroke is the second leading cause of death in the world. Ischemic stroke, caused by the blockage of intracranial arteries, accounts for approximately 80% of strokes. Among this proportion, acute ischemic stroke, usually caused by the sudden formation of blood clots, can cause fatal blockages in arteries. We proposed a unique blood clot retriever for the treatment of acute ischemic stroke, and conducted a series of tasks, including design, computer simulation, prototyping, and bench testing, for the proof of concept. Unlike most blood clot retrievers used today, our novel design deviates from traditional stent-like blood clot retrievers and uses large closed cells, irregular spikes, and strut protrusions to achieve maximum entanglement for better retrieval performance. Experimental results showed that the retrieval rate of our blood clot retriever was 79%, which demonstrated the feasibility of our new design concept.
A Self-Established “Machining-Measurement-Evaluation” Integrated Platform for Taper Cutting Experiments and Applications
Authors: Yang Xudong , Li Zexiao , Zhu Linlin , Dong Yuchu , Liu Lei , Miao Li , Zhang Xiaodong
Published: August 2021

Taper-cutting experiments are important means of exploring the nano-cutting mechanisms of hard and brittle materials. Under current cutting conditions, the brittle-ductile transition depth (BDTD) of a material can be obtained through a taper-cutting experiment. However, taper-cutting experiments mostly rely on ultra-precision machining tools, which have a low efficiency and high cost, and it is thus difficult to realize in situ measurements. For taper-cut surfaces, three-dimensional microscopy and two-dimensional image calculation methods are generally used to obtain the BDTDs of materials, which have a great degree of subjectivity, leading to low accuracy. In this paper, an integrated system-processing platform is designed and established in order to realize the processing, measurement, and evaluation of taper-cutting experiments on hard and brittle materials. A spectral confocal sensor is introduced to assist in the assembly and adjustment of the workpiece. This system can directly perform taper-cutting experiments rather than using ultra-precision machining tools, and a small white light interference sensor is integrated for in situ measurement of the three-dimensional topography of the cutting surface. A method for the calculation of BDTD is proposed in order to accurately obtain the BDTDs of materials based on three-dimensional data that are supplemented by two-dimensional images. The results show that the cutting effects of the integrated platform on taper cutting have a strong agreement with the effects of ultra-precision machining tools, thus proving the stability and reliability of the integrated platform. The two-dimensional image measurement results show that the proposed measurement method is accurate and feasible. Finally, microstructure arrays were fabricated on the integrated platform as a typical case of a high-precision application.
Interactions of the Insect-Specific Palm Creek Virus with Zika and Chikungunya Viruses in Aedes Mosquitoes
Authors: Koh Cassandra , Henrion-Lacritick Annabelle , Frangeul Lionel , Saleh Maria-Carla
Published: August 2021

Palm Creek virus (PCV) is an insect-specific flavivirus that can interfere with the replication of mosquito-borne flaviviruses in Culex mosquitoes, thereby potentially reducing disease transmission. We examined whether PCV could interfere with arbovirus replication in Aedes (Ae.) aegypti and Ae. albopictus mosquitoes, major vectors for many prominent mosquito-borne viral diseases. We infected laboratory colonies of Ae. aegypti and Ae. albopictus with PCV to evaluate infection dynamics. PCV infection was found to persist to at least 21 days post-infection and could be detected in the midguts and ovaries. We then assayed for PCV–arbovirus interference by orally challenging PCV-infected mosquitoes with Zika and chikungunya viruses. For both arboviruses, PCV infection had no effect on infection and transmission rates, indicating limited potential as a method of intervention for Aedes-transmitted arboviruses. We also explored the hypothesis that PCV–arbovirus interference is mediated by the small interfering RNA pathway in silico. Our findings indicate that RNA interference is unlikely to underlie the mechanism of arbovirus inhibition and emphasise the need for empirical examination of individual pairs of insect-specific viruses and arboviruses to fully understand their impact on arbovirus transmission.
Irreplaceable Role of Amendment-Based Strategies to Enhance Soil Health and Disease Suppression in Potato Production
Authors: Hao Jianjun , Ashley Katherine
Published: August 2021

Soilborne diseases are a major constraining factor to soil health and plant health in potato production. In the toolbox of crop management, soil amendments have shown benefits to control these diseases and improve soil quality. Most amendments provide nutrients to plants and suppress multiple soilborne pathogens. Soil amendments are naturally derived materials and products and can be classified into fresh or living plants, organic or inorganic matters, and microbial supplements. Fresh plants have unique functions and continuously exude chemicals to interact with soil microbes. Organic and inorganic matter contain high levels of nutrients, including nitrogen and carbon that plants and soil microorganisms need. Soil microorganisms, whether being artificially added or indigenously existing, are a key factor in plant health. Microbial communities can be considered as a biological reactor in an ecosystem, which suppress soilborne pathogens in various mechanisms and turn soil organic matter into absorbable forms for plants, regardless of amendment types. Therefore, soil amendments serve as an energy input, nutrient source, and a driving force of microbial activities. Advanced technologies, such as microbiome analyses, make it possible to analyze soil microbial communities and soil health. As research advances on mechanisms and functions, amendment-based strategies will play an important role in enhancing soil health and disease suppression for better potato production.
Synthesis and Characterization of Gefitinib and Paclitaxel Mono and Dual Drug-Loaded Blood Cockle Shells (Anadara granosa)-Derived Aragonite CaCO3 Nanoparticles
Authors: Chemmalar S. , Intan-Shameha Abdul Razak , Abdullah Che Azurahanim Che , Ab Razak Nor Asma , Yusof Loqman Mohamad , Ajat Mokrish , Gowthaman N. S. K. , Bakar Md Zuki Abu
Published: August 2021

Calcium carbonate has slowly paved its way into the field of nanomaterial research due to its inherent properties: biocompatibility, pH-sensitivity, and slow biodegradability. In our efforts to synthesize calcium carbonate nanoparticles (CSCaCO3NP) from blood cockle shells (Anadara granosa), we developed a simple method to synthesize CSCaCO3NP, and loaded them with gefitinib (GEF) and paclitaxel (PTXL) to produce mono drug-loaded GEF-CSCaCO3NP, PTXL-CSCaCO3NP, and dual drug-loaded GEF-PTXL-CSCaCO3NP without usage of toxic chemicals. Fourier-transform infrared spectroscopy (FTIR) results reveal that the drugs are bound to CSCaCO3NP. Scanning electron microscopy studies reveal that the CSCaCO3NP, GEF-CSCaCO3NP, PTXL-CSCaCO3NP, and GEF-PTXL-CSCaCO3NP are almost spherical nanoparticles, with a diameter of 63.9 ± 22.3, 83.9 ± 28.2, 78.2 ± 26.4, and 87.2 ± 26.7 (nm), respectively. Dynamic light scattering (DLS) and N2 adsorption-desorption experiments revealed that the synthesized nanoparticles are negatively charged and mesoporous, with surface areas ranging from ~8 to 10 (m2/g). Powder X-ray diffraction (PXRD) confirms that the synthesized nanoparticles are aragonite. The CSCaCO3NP show excellent alkalinization property in plasma simulating conditions and greater solubility in a moderately acidic pH medium. The release of drugs from the nanoparticles showed zero order kinetics with a slow and sustained release. Therefore, the physico-chemical characteristics and in vitro findings suggest that the drug loaded CSCaCO3NP represent a promising drug delivery system to deliver GEF and PTXL against breast cancer.
Epoxy/Ionic Liquid-Modified Mica Nanocomposites: Network Formation–Network Degradation Correlation
Authors: Jouyandeh Maryam , Akbari Vahideh , Paran Seyed Mohammad Reza , Livi Sébastien , Lins Luanda , Vahabi Henri , Saeb Mohammad Reza
Published: August 2021

We synthesized pristine mica (Mica) and N-octadecyl-N’-octadecyl imidazolium iodide (IM) modified mica (Mica-IM), characterized it, and applied it at 0.1–5.0 wt.% loading to prepare epoxy nanocomposites. Dynamic differential scanning calorimetry (DSC) was carried out for the analysis of the cure potential and kinetics of epoxy/Mica and epoxy/Mica-IM curing reaction with amine curing agents at low loading of 0.1 wt.% to avoid particle aggregation. The dimensionless Cure Index (CI) was used for qualitative analysis of epoxy crosslinking in the presence of Mica and Mica-IM, while qualitative cure behavior and kinetics were studied by using isoconversional methods. The results indicated that both Mica and Mica-IM improved the curability of epoxy system from a Poor to Good state when varying the heating rate in the interval of 5–15 °C min−1. The isoconversional methods suggested a lower activation energy for epoxy nanocomposites with respect to the blank epoxy; thus, Mica and Mica-IM improved crosslinking of epoxy. The higher order of autocatalytic reaction for epoxy/Mica-IM was indicative of the role of liquid crystals in the epoxide ring opening. The glass transition temperature for nanocomposites containing Mica and Mica-IM was also lower than the neat epoxy. This means that nanoparticles participated the reaction because of being reactive, which decelerated segmental motion of the epoxy chains. The kinetics of the thermal decomposition were evaluated for the neat and mica incorporated epoxy nanocomposites epoxy with varying Mica and Mica-IM amounts in the system (0.5, 2.0 and 5.0 wt.%) and heating rates. The epoxy/Mica-IM at 2.0 wt.% of nanoparticle showed the highest thermal stability, featured by the maximum value of activation energy devoted to the assigned system. The kinetics of the network formation and network degradation were correlated to demonstrate how molecular-level transformations can be viewed semi-experimentally.
Topological Phase and Quantum Anomalous Hall Effect in Ferromagnetic Transition-Metal Dichalcogenides Monolayer 1T−VSe2
Authors: Huang Angus , Chen Chin-Hsuan , Chang Ching-Hao , Jeng Horng-Tay
Published: August 2021

Magnetic two-dimensional (2D) van der Waals materials have attracted tremendous attention because of their high potential in spintronics. In particular, the quantum anomalous Hall (QAH) effect in magnetic 2D layers shows a very promising prospect for hosting Majorana zero modes at the topologically protected edge states in proximity to superconductors. However, the QAH effect has not yet been experimentally realized in monolayer systems to date. In this work, we study the electronic structures and topological properties of the 2D ferromagnetic transition-metal dichalcogenides (TMD) monolayer 1T−VSe2 by first-principles calculations with the Heyd–Scuseria–Ernzerhof (HSE) functional. We find that the spin-orbit coupling (SOC) opens a continuous band gap at the magnetic Weyl-like crossing point hosting the quantum anomalous Hall effect with Chern number C=2. Moreover, we demonstrate the topologically protected edge states and intrinsic (spin) Hall conductivity in this magnetic 2D TMD system. Our results indicate that 1T−VSe2 monolayer serves as a stoichiometric quantum anomalous Hall material.
A Graded Approach for Evaluating Health Claims about Plant-Based Food Supplements: Application of a Case Study Methodology
Authors: Chevallier Hélène , Herpin Florent , Kergosien Hélène , Ventura Gabrielle , Allaert François-André
Published: August 2021

The implementation of REGULATION (EC) No 1924/2006 has led to the formation of a list of health claims that can be used in food supplements (EU 432/2012). However, such supplements are often composed of plant preparations with claims omitted from this list. The peculiarity of plants is related to their long history of use, that could allow claims based on traditionally recognized health effects. In addition, the scientific literature has been enriched over the years through clinical studies that have assessed the bioavailability and efficacy of bioactive components, and investigated their mechanisms of action. Based on existing recognized models which aim to classify research according to the level of scientific evidence, Synadiet developed a three-grade model (A, B or C) for assessing plants health claims. In this paper, the applicability of the model is illustrated through an example for which a Grade B health claim attesting the possible contribution of red clover isoflavones to the improvement of blood lipid levels in postmenopausal women has been attributed. The model appears able to be easily extrapolated to claims pertaining to other plants. If adopted by consensus at European level, this model could initiate the implementation of a positive list of health claims on plant preparations.