bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of CrSi2-Containing Master Alloys for Modification of Fe-Containing Intermetallic Compounds in Aluminum Alloys
Authors: Sun Jincheng , Takahashi Aiga , Higashi Kennosuke , Yamamoto Takuya , Komarov Sergey
Published: November 2022

Aluminum contaminations, particularly iron, present a serious challenge to aluminum recycling technology. This is why many studies have focused on the reduction of detrimental effects of iron-containing contaminations through addition of elements such as manganese and chromium. However, the desirable modifying effect is often difficult to achieve because it would require concentrations of added elements greater than the allowable limits for many aluminum alloys. Thus, an alternative way to obtain the modifying effect, by using a much smaller amount of the modifying elements which are added to the aluminum melt as solid particles, was proposed in this study. The main goal of the present study was to investigate the possibilities of fabricating an aluminum master alloy by adding CrSi2 particles onto the surface of the vortex formed during mechanical agitation of molten aluminum. Two kinds of CrSi2 powder were used: one was commercial powder, and the other was self-synthesized CrSi2 via mechanical alloying by planetary ball milling. The results revealed that CrSi2 particles with a larger size penetrate the melt better. Particles of three kinds were found to exist in the Al melt after the addition of CrSi2 powder: (1) inclusions of eutectic origin formed at the last stage of crystallization, (2) mixtures of Al-Cr compounds and original CrSi2 particles and (3) original CrSi2 particles. Low melt temperatures and short treatment times were found to favor the fabrication of master alloys because they impeded the dissolution of CrSi2 particles into the Al melt and, thus, allowed one to fabricate the master alloy containing the particles of the second and third types.
Enhanced Piezoelectric Properties in a Single-Phase Region of Sm-Modified Lead-Free (Ba,Ca)(Zr,Ti)O3 Ceramics
Authors: Xiao Andong , Xie Xuefan , He Liqiang , Yang Yang , Ji Yuanchao
Published: November 2022

In ferroelectric materials, phase boundaries such as the morphotropic phase boundary (MPB) and polymorphic phase boundary (PPB) have been widely utilized to enhance the piezoelectric properties. However, for a single-ferroelectric-phase system, there are few effective paradigms to achieve the enhancement of piezoelectric properties. Herein, we report an unexpected finding that largely enhanced piezoelectric properties occur in a single-tetragonal-ferroelectric-phase region in the Sm-modified (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT-xSm) system. An electrostrain maximum (0.13%) appears in the single-phase region of the BZCT-0.5Sm composition with the maximum polarization (Pm = 18.37 µC/cm2) and piezoelectric coefficient (d33 = 396 pC/N) and the minimum coercive field (EC = 3.30 kV/cm) at room temperature. Such an enhanced piezoelectric effect is due to the synergistic effect of large lattice distortion and domain miniaturization on the basis of the transmission electron microscope (TEM) observation and X-ray diffraction (XRD) Rietveld refinement. Our work may provide new insights into the design of high-performance ferroelectrics in the single-phase region.
Hairpin Windings for Electric Vehicle Motors: Modeling and Investigation of AC Loss-Mitigating Approaches
Authors: Shams Ghahfarokhi Payam , Podgornovs Andrejs , Cardoso Antonio J. Marques , Kallaste Ants , Belahcen Anouar , Vaimann Toomas
Published: November 2022

The hairpin winding configuration has been attracting attention as a solution to increase the power density of electric vehicle motors by enhancing the slot-filling factor. However, this winding configuration brings high AC losses during high-speed operation and we require new approaches to tackle this challenge. This paper considers reducing AC losses by proposing two main methods: correct transposition of conductors in parallel paths, and enhancing the number of conductor layers in a slot. First, the proper connection of conductors in parallel paths is considered, and the essential rules for this purpose are described. Next, the paper uses a numerical approach to deal with the effect of incorrect conductor transposition in winding paths on generating additional AC losses due to circulating currents. Finally, the impact of the number of conductor layers in the mitigation of AC losses is also discussed in detail. According to the results, by increasing the number of layers, ohmic losses in the layer near the slot opening dramatically decrease. For instance, ohmic losses in the layer near the slot opening of the eight-layer setup were 82% less than the two-layer layout.
Multi-Conditional Optimization of a High-Specific-Speed Axial Flow Pump Impeller Based on Machine Learning
Authors: Sun Zhuangzhuang , Tang Fangping , Shi Lijian , Liu Haiyu
Published: November 2022

In order to widen the range of high-efficiency area of a high-specific-speed axial flow pump and to improve the operating efficiency under non-design conditions, the parameters of the axial flow pump blades were optimized. An optimization system based on computational fluid dynamics (CFD), optimized Latin hypercube sampling (OLHS), machine learning (ML), and multi-island genetic algorithm (MIGA) was established. The prediction effects of three machine learning models based on Bayesian optimization, support vector machine regression (SVR), Gaussian process regression (GPR), and fully connected neural network (FNN) on the performance of the axial flow pump were compared. The results show that the GPR model has the highest prediction accuracy for the impeller head and weighted efficiency. Compared to the original impeller, the optimized impeller is forward skewed and backward swept, and the weighted efficiency of the impeller increases by 1.31 percentage points. The efficiency of the pump section at 0.8Qd, 1.0Qd, and 1.2Qd increases by about 1.1, 1.4, and 1.6 percentage points, respectively, which meets the optimization requirements. After optimization, the internal flow field of the impeller is more stable; the entropy production in the impeller reduces; the spanwise distribution of the total pressure coefficient and the axial velocity coefficient at the impeller outlet are more uniform; and the flow separation near the hub at the blade trailing edge is restrained. This research can provide a reference for the efficient operation of pumping stations and the optimal design of axial flow pumps under multiple working conditions.
A Comparative Investigation of Mechanical Properties of TiB2/Cr Multilayer Film by Indentation
Authors: Chen Simeng , Wu Zhengtao , Wang Qimin
Published: November 2022

Alternating TiB2-dcMS and Cr-HiPIMS layers are used to fabricate TiB2/Cr multilayer films. Introducing a 5-nm-thick Cr interlayer deposited under a substrate bias of −60 V produces slight increases in both film hardness and elastic modulus. The TEM observation indicates that the Cr grains favor epitaxial growth on the TiB2 interlayer, forming a coherent TiB2/Cr interface. This improves hardness. Mechanic measurement by using AFM illustrates that the coherent interface increases the elastic modulus of the Cr up to ~280 GPa, which is significantly higher than bulk material.
New Delay-Partitioning LK-Functional for Stability Analysis with Neutral Type Systems
Authors: Ding Liming , Chen Liqin , He Dajiang , Xiang Weiwei
Published: November 2022

This paper investigates the stability issues associated with neutral-type delay systems. Firstly, the delay-partitioning method is employed to construct a brand-new LK-functional candidate. The discrete delay and a neutral delay are divided into several piecewise points through a relaxable sequence of constant numbers, are increasing at a steady rate and are not larger than 1. Secondly, to fully use the interconnection information among the delayed state vectors, a new LK-functional is constructed. Thirdly, the recently published single/multiple integral inequalities are employed to bound the derivative of the newly developed LK function. Finally, a novel stability criterion for neutral systems is developed based on the above treatment. Furthermore, a new corollary is also proposed for the condition of τ=h. The benefits and productivities of our method are demonstrated by numerical examples.
On the Non-Local Boundary Value Problem from the Probabilistic Viewpoint
Authors: D’Ovidio Mirko
Published: November 2022

We provide a short introduction of new and well-known facts relating non-local operators and irregular domains. Cauchy problems and boundary value problems are considered in case non-local operators are involved. Such problems lead to anomalous behavior on the bulk and on the surface of a given domain, respectively. Such a behavior should be considered (in a macroscopic viewpoint) in order to describe regular motion on irregular domains (in the microscopic viewpoint).
Binned Term Count: An Alternative to Term Frequency for Text Categorization
Authors: Shehzad Farhan , Rehman Abdur , Javed Kashif , Alnowibet Khalid A. , Babri Haroon A. , Rauf Hafiz Tayyab
Published: November 2022

In text categorization, a well-known problem related to document length is that larger term counts in longer documents cause classification algorithms to become biased. The effect of document length can be eliminated by normalizing term counts, thus reducing the bias towards longer documents. This gives us term frequency (TF), which in conjunction with inverse document frequency (IDF) became the most commonly used term weighting scheme to capture the importance of a term in a document and corpus. However, normalization may cause term frequency of a term in a related document to become equal or smaller than its term frequency in an unrelated document, thus perturbing a term’s strength from its true worth. In this paper, we solve this problem by introducing a non-linear mapping of term frequency. This alternative to TF is called binned term count (BTC). The newly proposed term frequency factor trims large term counts before normalization, thus moderating the normalization effect on large documents. To investigate the effectiveness of BTC, we compare it against the original TF and its more recently proposed alternative named modified term frequency (MTF). In our experiments, each of these term frequency factors (BTC, TF, and MTF) is combined with four well-known collection frequency factors (IDF), RF, IGM, and MONO and the performance of each of the resulting term weighting schemes is evaluated on three standard datasets (Reuters (R8-21578), 20-Newsgroups, and WebKB) using support vector machines and K-nearest neighbor classifiers. To determine whether BTC is statistically better than TF and MTF, we have applied the paired two-sided t-test on the macro F1 results. Overall, BTC is found to be 52% statistically significant than TF and MTF. Furthermore, the highest macro F1 value on the three datasets was achieved by BTC-based term weighting schemes.
Social Recommendation Based on Multi-Auxiliary Information Constrastive Learning
Authors: Jiang Feng , Cao Yang , Wu Huan , Wang Xibin , Song Yuqi , Gao Min
Published: November 2022

Social recommendation can effectively alleviate the problems of data sparseness and the cold start of recommendation systems, attracting widespread attention from researchers and industry. Current social recommendation models use social relations to alleviate the problem of data sparsity and improve recommendation performance. Although self-supervised learning based on user–item interaction can enhance the performance of such models, multi-auxiliary information is neglected in the learning process. Therefore, we propose a model based on self-supervision and multi-auxiliary information using multi-auxiliary information, such as user social relationships and item association relationships, to make recommendations. Specifically, the user social relationship and item association relationship are combined to form a multi-auxiliary information graph. The user–item interaction relationship is also integrated into the same heterogeneous graph so that multiple pieces of information can be spread in the same graph. In addition, we utilize the graph convolution method to learn user and item embeddings, whereby the user embeddings reflect both user–item interaction and user social relationships, and the item embeddings reflect user–item interaction and item association relationships. We also design multi-view self-supervising auxiliary tasks based on the constructed multi-auxiliary views. Signals generated by self-supervised auxiliary tasks can alleviate the problem of data sparsity, further improving user/item embedding quality and recommendation performance. Extensive experiments on two public datasets verify the superiority of the proposed model.
Solving System of Mixed Variational Inclusions Involving Generalized Cayley Operator and Generalized Yosida Approximation Operator with Error Terms in q-Uniformly Smooth Space
Authors: Ahmad Rais , Ishtyak Mohd , Rajpoot Arvind Kumar , Wang Yuanheng
Published: November 2022

In this paper, we solve a system of mixed variational inclusions involving a generalized Cayley operator and the generalized Yosida approximation operator. An iterative algorithm is suggested to discuss the convergence analysis. We have shown that our system admits a unique solution by using the properties of q-uniformly smooth Banach space, and we discuss the convergence criteria for sequences generated by iterative algorithm. Two examples are constructed, and an application is provided.
Research on the Calculation Method of Electrostatic Field of a Thunderstorm Cloud
Authors: Wang Lin , Wan Haojiang , Chen Yazhou
Published: November 2022

The electrostatic field in the space excited by a thunderstorm cloud reflects the trend of the spatial potential and has a great influence on the selection of lightning discharge paths. Some studies have used an approximate method to calculate the electrostatic field excited by a thunderstorm cloud, but the error is still relatively large. In order to improve the computational accuracy, the second-order approximate solution of the electric field is obtained in this paper by using a binomial expansion of the complex quantized function, discarding the higher-order small terms and integrating the main term according to the convergence of the function. The first-order approximate solution and the second-order approximate solution are used to calculate the electrostatic field excited by a thunderstorm cloud using the same version of MATLAB on the same configuration of computers. By comparison, it is found that the computation time using the two approximate solutions is not much different, but the error between the second-order approximate solution and the exact solution is significantly smaller than that between the first-order approximate solution and the exact solution. It is shown that using the second-order approximate solution to calculate the electrostatic field of a thunderstorm cloud can greatly improve the computational accuracy without sacrificing the computational efficiency, which is of great significance for the accurate warning when lightning is approaching.
Existence and Approximation of Fixed Points of Enriched φ-Contractions in Banach Spaces
Authors: Berinde Vasile , Harjani Jackie , Sadarangani Kishin
Published: November 2022

We introduce the class of enriched φ-contractions in Banach spaces as a natural generalization of φ-contractions and study the existence and approximation of the fixed points of mappings in this new class, which is shown to be an unsaturated class of mappings in the setting of a Banach space. We illustrated the usefulness of our fixed point results by studying the existence and uniqueness of the solutions of some second order (p,q)-difference equations with integral boundary value conditions.
Deep Neural Network Memory Performance and Throughput Modeling and Simulation Framework
Authors: Gabbay Freddy , Lev Aharoni Rotem , Schweitzer Ori
Published: November 2022

Deep neural networks (DNNs) are widely used in various artificial intelligence applications and platforms, such as sensors in internet of things (IoT) devices, speech and image recognition in mobile systems, and web searching in data centers. While DNNs achieve remarkable prediction accuracy, they introduce major computational and memory bandwidth challenges due to the increasing model complexity and the growing amount of data used for training and inference. These challenges introduce major difficulties not only due to the constraints of system cost, performance, and energy consumption, but also due to limitations in currently available memory bandwidth. The recent advances in semiconductor technologies have further intensified the gap between computational hardware performance and memory systems bandwidth. Consequently, memory systems are, today, a major performance bottleneck for DNN applications. In this paper, we present DRAMA, a deep neural network memory simulator. DRAMA extends the SCALE-Sim simulator for DNN inference on systolic arrays with a detailed, accurate, and extensive modeling and simulation environment of the memory system. DRAMA can simulate in detail the hierarchical main memory components—such as memory channels, modules, ranks, and banks—and related timing parameters. In addition, DRAMA can explore tradeoffs for memory system performance and identify bottlenecks for different DNNs and memory architectures. We demonstrate DRAMA’s capabilities through a set of experimental simulations based on several use cases.
Generalized Spacelike Normal Curves in Minkowski Three-Space
Authors: Tashkandy Yusra , Emam Walid , Cesarano Clemente , Abd El-Raouf M. M. , Elsharkawy Ayman
Published: November 2022

Equiform geometry is considered an extension of other geometries. Furthermore, an equiform frame is a generalization of the Frenet frame. In this study, we begin by defining the term “equiform parameter (EQP)”, “equiform frame”, and “equiform formulas (EQF)” in regard to the Minkowski three-space. Second, we define spacelike normal curves (SPN) in Minkowski three-space and present a variety of descriptions of these curves with equiform spacelike (EQS) or equiform timelike (EQN) principal normals in Minkowski three-space. Third, we discuss the implications of these findings. Finally, an example is given to illustrate our theoretical results.
A Genetic Hyper-Heuristic for an Order Scheduling Problem with Two Scenario-Dependent Parameters in a Parallel-Machine Environment
Authors: Li Lung-Yu , Xu Jian-You , Cheng Shuenn-Ren , Zhang Xingong , Lin Win-Chin , Lin Jia-Cheng , Wu Zong-Lin , Wu Chin-Chia
Published: November 2022

Studies on the customer order scheduling problem have been attracting increasing attention. Most current approaches consider that either component processing times for customer orders on each machine are constant or all customer orders are available at the outset of production planning. However, these assumptions do not hold in real-world applications. Uncertainty may be caused by multiple issues including a machine breakdown, the working environment changing, and workers’ instability. On the basis of these factors, we introduced a parallel-machine customer order scheduling problem with two scenario-dependent component processing times, due dates, and ready times. The objective was to identify an appropriate and robust schedule for minimizing the maximum of the sum of weighted numbers of tardy orders among the considered scenarios. To solve this difficult problem, we derived a few dominant properties and a lower bound for determining an optimal solution. Subsequently, we considered three variants of Moore’s algorithm, a genetic algorithm, and a genetic-algorithm-based hyper-heuristic that incorporated the proposed seven low-level heuristics to solve this problem. Finally, the performances of all proposed algorithms were evaluated.
Multibranch Attention Mechanism Based on Channel and Spatial Attention Fusion
Authors: Mao Guojun , Liao Guanyi , Zhu Hengliang , Sun Bo
Published: November 2022

Recently, it has been demonstrated that the performance of an object detection network can be improved by embedding an attention module into it. In this work, we propose a lightweight and effective attention mechanism named multibranch attention (M3Att). For the input feature map, our M3Att first uses the grouped convolutional layer with a pyramid structure for feature extraction, and then calculates channel attention and spatial attention simultaneously and fuses them to obtain more complementary features. It is a “plug and play” module that can be easily added to the object detection network and significantly improves the performance of the object detection network with a small increase in parameters. We demonstrate the effectiveness of M3Att on various challenging object detection tasks, including PASCAL VOC2007, PASCAL VOC2012, KITTI, and Zhanjiang Underwater Robot Competition. The experimental results show that this method dramatically improves the object detection effect, especially for the PASCAL VOC2007, and the mapping index of the original network increased by 4.93% when embedded in the YOLOV4 (You Only Look Once v4) network.
Obstructive Sleep Apnea Disrupts Glycemic Control in Obese Individuals
Authors: Seifen Christopher , Pordzik Johannes , Ludwig Katharina , Bahr Katharina , Schupp Cornelia , Matthias Christoph , Simon Perikles , Gouveris Haralampos
Published: November 2022

The link between obstructive sleep apnea (OSA) and obesity, and their common comorbidities such as diabetes mellitus (DM) or cardiovascular diseases, is not fully understood. The aim of this study was to investigate the possible association of OSA severity in obese individuals with polysomnography-based sleep parameters, as well as C-reactive protein (CRP) and glycated hemoglobin (HbA1c) serum levels. Polysomnographic recordings and blood samples were retrospectively compared between a group of 23 adult obese individuals with mild OSA (apnea–hypopnea index (AHI) = 7.5 (5.5–12.5)/h, age = 42.57 ± 11.44 years, 16 male, 7 female, body mass index (BMI) = 37.35 ± 3.88 kg/m2) and an age-, sex-, and BMI-matched group of individuals with moderate or severe OSA (AHI 41.5 (25.7–71.8)/h, age = 43.43 ± 11.96 years, 16 male, 7 female, BMI = 37.87 ± 4.74 kg/m2). All respiratory sleep-associated parameters were significantly higher in individuals with moderate and severe OSA compared to those with mild OSA. CRP levels did not differ between the two OSA severity groups. However, serum levels of HbA1c were significantly higher in the moderate/severe OSA group. Therefore, OSA severity may have a significant impact on glycemic control in obese individuals. Additionally, OSA severity did not appear to be further associated with systemic inflammation in obese individuals. Obese individuals may benefit not only from lifestyle modification, but also from OSA screening and treatment, particularly to prevent DM-associated disorders and conditions.
Research Progress, Trends, and Current State of Development on PEMFC-New Insights from a Bibliometric Analysis and Characteristics of Two Decades of Research Output
Authors: Agyekum Ephraim Bonah , Ampah Jeffrey Dankwa , Wilberforce Tabbi , Afrane Sandylove , Nutakor Christabel
Published: November 2022

The consumption of hydrogen could increase by sixfold in 2050 compared to 2020 levels, reaching about 530 Mt. Against this backdrop, the proton exchange membrane fuel cell (PEMFC) has been a major research area in the field of energy engineering. Several reviews have been provided in the existing corpus of literature on PEMFC, but questions related to their evolutionary nuances and research hotspots remain largely unanswered. To fill this gap, the current review uses bibliometric analysis to analyze PEMFC articles indexed in the Scopus database that were published between 2000–2021. It has been revealed that the research field is growing at an annual average growth rate of 19.35%, with publications from 2016 to 2012 alone making up 46% of the total articles available since 2000. As the two most energy-consuming economies in the world, the contributions made towards the progress of PEMFC research have largely been from China and the US. From the research trend found in this investigation, it is clear that the focus of the researchers in the field has largely been to improve the performance and efficiency of PEMFC and its components, which is evident from dominating keywords or phrases such as ‘oxygen reduction reaction’, ‘electrocatalysis’, ‘proton exchange membrane’, ‘gas diffusion layer’, ‘water management’, ‘polybenzimidazole’, ‘durability’, and ‘bipolar plate’. We anticipate that the provision of the research themes that have emerged in the PEMFC field in the last two decades from the scientific mapping technique will guide existing and prospective researchers in the field going forward.
Effect of Pulsed Electric Field on the Electrodialysis Performance of Phosphate-Containing Solutions
Authors: Rybalkina Olesya , Solonchenko Ksenia , Chuprynina Daria , Pismenskaya Natalia , Nikonenko Victor
Published: November 2022

A comparative analysis of mass transfer characteristics and energy consumption was carried out for the electrodialysis recovery of PV from of NaH2PO4 solutions and multicomponent (0.045 M NaxH(3−x)PO4, 0.02 M KCl, 0.045 M KOH, 0.028 M CaCl2, and 0.012 M MgCl2, pH 6.0 ± 0.1) solution in conventional continuous current (CC) and pulsed electric field (PEF) modes. The advantages of using PEF in comparison with CC mode are shown to increase the current efficiency and reduce energy consumption, as well as reduce scaling on heterogeneous anion-exchange membranes. It has been shown that PEF contributes to the suppression of the “acid dissociation” phenomenon, which is specific for anion-exchange membranes in phosphate-containing solutions. Pulse and pause lapse 0.1 s–0.1 s and duty cycle 1/2 were found to be optimal among the studied PEF parameters.
Variant Pairing of Lath Bainite and Martensite in an Ultra-High-Strength Steel
Authors: Li Meiying , Wang Shun , Jia Tao , Zhao Xianming
Published: November 2022

The mixed structure of lath bainite and martensite was obtained by isothermal transformation tests at 698 K, 673 K and 623 K in ultra-high-strength steel. The interweaving mode of lath bainite and martensite was revealed by colored metallography and band contrast maps based on Gaussian fit. The crystallographic characteristics were analyzed in terms of variant pairing. The twin-related V1/V2 variant pairs were found in the region with high band contrast (BC) values, inferred as lath bainite. While in the low-BC value region, which was inferred as lath martensite, besides the dominated twin-related V1/V2 variant pair, V1/V4 variant pairs with low-angle grain boundaries were occasionally revealed. According to the classification by Takayama et al., both variant pairings of lath bainite and martensite in this work correspond to a type II mode. The present work has confirmed, even with complex microstructure, i.e., mixed lath bainite and martensite were formed depending on the processing route, bainite and martensite still follow their own rules of variant pairing.
Effect of Heat Treatment on the Resulting Dimensional Characteristics of the C45 Carbon Steel after Turning
Authors: Moravčíková Jana , Moravčík Roman , Palcut Marián
Published: November 2022

The presented article deals with the influence of the heat treatment of C45 steel on the surface quality after turning. Turning is a machining technology used to prepare specific geometrical characteristics of surface and dimensional quality. In the present paper, the same turning conditions were used for the turning treatment of differently heat-treated steels. The soft annealed state, normalized state, hardened state, quenched and tempered at 530 °C state and quenched and tempered at 660 °C state have been analyzed. By using this approach, it has been possible to evaluate the effects of hardening and machining on the resulting parameters after turning (roughness, cylindricity and circularity). The highest hardness was observed in the steel after the hardening process (694 ± 9 HV 10). The hardening has negatively influenced the surface quality. The high hardness was related to martensite formation and caused a damage to the cutting edge of the cut insert used, leading to a significant change in geometrical accuracy. The cylindricity change achieved 0.15 ± 0.03 mm which was significantly higher compared to the theoretical value of the diameter of the machined steel bar. An inaccuracy was also observed in diameter dimension. These inaccuracies were caused by the wear of the cutting edge of the tool used in cutting parameters setting.
Manipulation of Magnetic Skyrmion Density in Continuous Ir/Co/Pt Multilayers
Authors: Cubukcu M. , Pöllath S. , Tacchi S. , Stacey A. , Darwin E. , Freeman C. W. F. , Barton C. , Hickey B. J. , Marrows C. H. , Carlotti G. , Back C. H. , Kazakova O.
Published: November 2022

We show that magnetic skyrmions can be stabilised at room temperature in continuous [Ir/Co/Pt]5 multilayers on SiO2/Si substrates without the prior application of electric current or magnetic field. While decreasing the Co thickness, a transition of the magnetic domain patterns from worm-like state to separated stripes is observed. The skyrmions are clearly imaged in both states using magnetic force microscopy. The density of skyrmions can be significantly enhanced after applying the “in-plane field procedure”. Our results provide means to manipulate magnetic skyrmion density, further allowing for the optimised engineering of skyrmion-based devices.
Nondestructive Wafer Level MEMS Piezoelectric Device Thickness Detection
Authors: Zhou Yongxin , Gu Yuandong , Zhang Songsong
Published: November 2022

This paper introduces a novel nondestructive wafer scale thin film thickness measurement method by detecting the reflected picosecond ultrasonic wave transmitting between different interfacial layers. Unlike other traditional approaches used for thickness inspection, this method is highly efficient in wafer scale, and even works for opaque material. As a demonstration, we took scandium doped aluminum nitride (AlScN) thin film and related piezoelectric stacking layers (e.g. Molybedenum/AlScN/Molybdenum) as the case study to explain the advantages of this approach. In our experiments, a laser with a wavelength of 515 nm was used to first measure the thickness of (1) a single Molybdenum (Mo) electrode layer in the range of 100–300 nm, and (2) a single AlScN piezoelectric layer in the range of 600–1000 nm. Then, (3) the combined stacking layers were measured. Finally, (4) the thickness of a standard piezoelectric composite structure (Mo/AlScN/Mo) was characterized based on the conclusions and derivation extracted from the aforementioned sets of experiments. This type of standard piezoelectric composite has been widely adopted in a variety of Micro-electromechanical systems (MEMS) devices such as the Piezoelectric Micromachined Ultrasonic Transducer (PMUT), the Film Bulk Acoustic Resonator (FBAR), the Surface Acoustic Wave (SAW) and more. A comparison between measurement data from both in-line and off-line (using Scanning Electron Microscope) methods was conducted. The result from such in situ 8-inch wafer scale measurements was in a good agreement with the SEM data.
Resistance Switching in Polycrystalline C12A7 Electride
Authors: Yushkov Ivan D. , Kamaev Gennadiy N. , Volodin Vladimir A. , Geydt Pavel V. , Kapishnikov Aleksandr V. , Volodin Alexander M.
Published: November 2022

The memory (memristive) properties of an electride material based on polycrystalline mayenite (C12A7:e−) were studied. The phase composition of the material has been confirmed by such methods as XRD, TEM, Raman, and infrared spectroscopy. The electride state was confirmed by conductivity measurements and EPR using a characteristic signal from F+—like centers, but the peak at 186 cm−1, corresponding to an electride with free electrons, was not observed explicitly in the Raman spectra. The temperature dependence of current–voltage characteristics in states with low and high resistance (LRS and HRS) has been studied. In the LRS state, the temperature dependence of the current has a non-Arrhenius character and is described by the Hurd quantum tunnelling model with a Berthelot temperature of 262 K, while in the HRS state, it can be described in terms of the Arrhenius model. In the latter case, the existence of two conduction regions, “impurity” and “intrinsic”, with corresponding activation energies of 25.5 and 40.6 meV, was assumed. The difference in conduction mechanisms is most likely associated with a change in the concentration of free electrons.
Thrombolytic Potential of Micromycetes from the Genus Tolypocladium, Obtained from White Sea Soils: Screening of Producers and Exoproteinases Properties
Authors: Fokichev N. S. , Kokaeva L. Yu. , Popova E. A. , Kurakov A. V. , Osmolovskiy A. A.
Published: November 2022

Thrombotherapy is an important approach in treatment of various diseases associated with pathologies of the cardiovascular and human hemostasis systems. Screening for producers of modern, specific, and safe thrombolytic substances is an important task for medicine and biotechnology. The aim of this study was to characterize thrombolytic potential of seven strains of micromycete belonging to the genus Tolypocladium, which was obtained from White Sea soils. The Tolypocladium inflatum 62a strain was considered the most promising producer of thrombolytic agent activities suitable for possible use in thrombotherapy or diagnostics of hemostasis pathologies. It demonstrated a high radial growth rate and was characterized not only by a sufficiently high value of enzymatic index in media with fibrin and fibrinogen but also by the highest specificity for fibrillar proteins among all strains. The preparation obtained from it demonstrated pronounced thrombolytic effectiveness and substrate specificity.
Influence of SARS-COV-2 Infection on Cytokine Production by Mitogen-Stimulated Peripheral Blood Mononuclear Cells and Neutrophils in COVID-19 Intensive Care Unit Patients
Authors: Essa Sahar , Shamsah Mohammed , Alsarraf Abdalaziz H. , Esmaeil Ali , Al-Shammasi Ahmed , Raghupathy Raj
Published: November 2022

We sought to investigate the influence of SARS-CoV-2 infection on the cytokine profiles of peripheral blood mononuclear cells (PBMCs) and neutrophils from coronavirus disease 2019 (COVID-19) intensive care unit (ICU) patients. Neutrophils and PBMCs were separated and stimulated with the mitogen phytohemagglutinin. Culture supernatants of mitogen-stimulated PBMCs and neutrophils from 88 COVID-19 ICU patients and 88 healthy controls were evaluated for levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon (IFN)-α, IFN-γ, interleukin (IL)-2, -4, -5, -6, -9, -10, -12, -17A, and tumor necrosis factor (TNF)-α using anti-cytokine antibody MACSPlex capture beads. Cytokine profiles of PBMCs showed significantly lower levels of GM-CSF, IFN-γ, IL-6, IL-9, IL-10, IL-17A, and TNF-α (p < 0.0001) in COVID-19 ICU patients. In contrast, COVID-19 ICU patients showed higher median levels of IL-2 (p < 0.001) and IL-5 (p < 0.01) by PBMCs. As for neutrophils, COVID-19 ICU patients showed significantly lower levels of GM-CSF, IFN-γ, IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-17A, IL-12, TNF-α (p < 0.0001), and IFN-α (p < 0.01). T-helper (Th)1:Th2 cytokine ratios revealed lower inflammatory cytokine for PBMCs and neutrophils in COVID-19 ICU patients. Cytokine production profiles and Th1:Th2 cytokine ratios suggest that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has an immunomodulatory effect on PBMCs and neutrophils. This study also suggests that the increased levels of several cytokines in the serum are not sourced from PBMCs and neutrophils.
Green Chemistry Based Synthesis of Zinc Oxide Nanoparticles Using Plant Derivatives of Calotropis gigantea (Giant Milkweed) and Its Biological Applications against Various Bacterial and Fungal Pathogens
Authors: Farooq Ammara , Khan Umair A. , Ali Haider , Sathish Manda , Naqvi Syed Atif Hasan , Iqbal Shehzad , Ali Haider , Mubeen Iqra , Amir Muhammad Bilal , Mosa Walid F. A. , Baazeem Alaa , Moustafa Mahmoud , Alrumman Sulaiman , Shati Ali , Negm Sally
Published: November 2022

Nanotechnology is a burning field of scientific interest for researchers in current era. Diverse plant materials are considered as potential tool in green chemistry based technologies for the synthesis of metal nanoparticles (NPs) to cope with the hazardous effects of synthetic chemicals, leading to severe abiotic climate change issues in today’s agriculture. This study aimed to determine the synthesis and characterization of metal-based nanoparticles using extracts of the selected plant Calotropis gigantea and to evaluate the enzyme-inhibition activities and antibacterial and antifungal activity of extracts of metal-based zinc nanoparticles using C. gigantea extracts. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). C. gigantea was examined for antimicrobial activity against clinical isolates of bacteria and fungi. The water, ethanolic, and acetone extracts of C. gigantea were studied for their antagonistic action against bacterial strains (E. coli, S. aureus, P. multocida, and B. subtilis) and selected fungal strains (A. paracistic, F. solani, A. niger, S. ferrugenium, and R. nigricans). In vitro antimicrobial activity was determined by the disc diffusion method, where C. gigantea was tested for AChE and BChE inhibitory activity using Ellman’s methodology. The kinetic analysis was performed by the proverbial Berthelot reaction for urease inhibition. The results showed that out of all the extracts tested, ethanolic and water extracts possessed zinc nanoparticles. These extracts showed the maximum zone of inhibition against F. solani and P. multocida and the lowest against S. ferrugenium and B. subtilis. A potential source of AChE inhibitors is certainly provided by the abundance of plants in nature. Numerous phyto-constituents, such as AChE and BChE inhibitors, have been reported in this communication. Water extract was active and has the potential for in vitro AChE and BChE inhibitory activity. The urease inhibition with flower extracts of C. gigantea revealed zinc nanoparticles in water extracts that competitively inhibited urease enzymes. In the case of cholinesterase enzymes, it was inferred that the water extract and zinc nanoparticles have more potential for inhibition of BChE than AChE and urease inhibition. Furthermore, zinc nanoparticles with water extract are active inthe inhibition of the bacterial strains E. coli, S. aureus, and P. multocida and the fungal strains A. paracistic, F. solani, and A. niger.
Significant Shifts in Microbial Communities Associated with Scleractinian Corals in Response to Algae Overgrowth
Authors: Lu Chunrong , Zhang Qi , Huang Qinyu , Wang Shuying , Qin Xiao , Ren Tianfei , Xie Rufeng , Su Hongfei
Published: November 2022

Microbes play a key role in reef dynamics, mediating the competition between scleractinian corals and benthic algae; however, major shifts in bacterial communities among coral species in response to increases in the abundance of algae are not well understood. We investigated the taxonomic composition of coral-associated microbial communities under algae-overgrowth conditions using 16S rRNA gene sequencing. The results showed that non-algal (i.e., healthy) tissue (HH) had lower bacterial abundance and diversity than tissue collected from the coral–algae interface boundary (HA) and areas of algae growth (AA). Specifically, the HA and AA samples had higher relative abundances of Saprospiraceae, Rhodobacteraceae, and Alteromonadaceae. Compared with Platygyra sp. and Montipora sp., the physiological response of Pocillopora sp. was more intense under algae-induced stress based on microbial gene function prediction. Our results indicate that algal pressure can significantly alter the microbial community structure and function of coral ecosystems. Our data thus provide new insight into the relationship between corals and their microbiome under environmental stress.
Functional Gastrointestinal Disorders with Psychiatric Symptoms: Involvement of the Microbiome–Gut–Brain Axis in the Pathophysiology and Case Management
Authors: Șchiopu Cristina Gabriela , Ștefănescu Cristinel , Boloș Alexandra , Diaconescu Smaranda , Gilca-Blanariu Georgiana-Emmanuela , Ștefănescu Gabriela
Published: November 2022

Functional Gastrointestinal Disorders have been an important cause of poor life quality in affected populations. The unclear etiology and pathophysiological mechanism alter the clinical evolution of the patient. Although a strong connection with psychological stress has been observed, it was not until recently that the gut–brain axis involvement has been revealed. Furthermore, the current literature not only promotes the gut–brain axis modulation as a therapeutical target for functional digestive disorders but also states that the gut microbiome has a main role in this bi-directional mechanism. Psychiatric symptoms are currently recognized as an equally important aspect of the clinical manifestation and modulation of both the digestive and central nervous systems and could be the best approach in restoring the balance. As such, this article proposes a detailed description of the physiology of the microbiome–gut–brain axis, the pathophysiology of the functional gastrointestinal disorders with psychiatric symptoms and current perspectives for therapeutical management, as revealed by the latest studies in the scientific literature.
Preparation and Characterization of Water-borne Polyurethane Based on Benzotriazole as Pendant Group with Different N-Alkylated Chain Extenders and Its Application in Anticorrosion
Authors: Bibi Aamna , Tsai Ethan , Lan Yun-Xiang , Chang Kung-Chin , Yeh Jui-Ming
Published: November 2022

A series of novel anti-corrosive coatings were synthesized successfully. Water-borne polyurethane (WPU) was synthesized using polyethylene glycol and modified by grafting benzotriazole (BTA) as a pendant group (WPU-g-BTA) and N-alkylated amines (ethylene diamine (A), diethylene triamine (B), triethylene tetramine (C)) as side-chain extenders. Fourier-transform infrared spectroscopy, thermogravimetry, and dynamic mechanical analyses were used to characterize the structural and thermomechanical properties of the samples. A gas permeability analyzer (GPA) was used to evaluate molecular barrier properties. The corrosion inhibition performance of WPU-g-BTA-A, WPU-g-BTA-B, and WPU-g-BTA-C coatings in 3.5 wt% NaCl solution was determined by electrochemical measurements. WPU-g-BTA-C coating synthesized with a high cross-linking density showed superior anticorrosive performance. The as-prepared coatings exhibited a very low icorr value of 0.02 µA.cm−2, a high Ecorr value of −0.02 V, as well as excellent inhibition efficiency (99.972%) and impedance (6.33 Ω) after 30 min of exposure.
Ru(II)(ƞ6-p-cymene) Conjugates Loaded onto Graphene Oxide: An Effective pH-Responsive Anticancer Drug Delivery System
Authors: Akhter Suffora , Arjmand Farukh , Pettinari Claudio , Tabassum Sartaj
Published: November 2022

Graphene oxide-based nanodrug delivery systems are considered one of the most promising platforms to deliver therapeutic drugs at the target site. In this study, Ru(II)(ƞ6-p-cymene) complexes containing the benzothiazole ligand were covalently anchored on graphene oxide using the ultrasonication method. The nanoconjugates GO-NCD-1 and GO-NCD-2 were characterized by FT-IR, UV-visible, 1H NMR, TGA, SEM, and TEM techniques, which confirmed the successful loading of both the complexes (NCD 1 and NCD 2) on the carrier with average particle diameter sizes of 17 ± 6.9 nm and 25 ± 6.5 nm. In vitro DNA binding studies of the nanoconjugates were carried out by employing various biophysical methods to investigate the binding interaction with the therapeutic target biomolecule and to quantify the intrinsic binding constant values useful to understand their binding affinity. Our results suggest (i) high Kb and Ksv values of the graphene-loaded conjugates (ii) effective cleavage of plasmid DNA at a lower concentration of 7.5 µM and 10 µM via an oxidative pathway, and (iii) fast release of NCD 2 at an acidic pH that could have a good impact on the controlled delivery of drug. It was found that 90% of the drug was released in an acidic pH (5.8 pH) environment in 48 h, therefore suggesting pH-responsive behavior of the drug delivery system. Molecular docking, DFT studies, and cytotoxicity activity against three cancer cell lines by SRB assay were also performed.
Rapid Capillary Electrophoresis Method for Simultaneous Determination of Abemaciclib, Ribociclib, and Palbociclib in Pharmaceutical Dosage Forms: A Green Approach
Authors: Mlinarić Zvonimir , Turković Lu , Begović Iva , Nigović Biljana , Sertić Miranda
Published: November 2022

Advances in the treatment of HR+/HER2- breast cancer phenotype have been made with the introduction of abemaciclib, ribociclib, and palbociclib, inhibitors of cyclin D dependent kinases 4 and 6 (CDK4/6). Here, a novel, fast, cheap, and green CE method for the simultaneous determination of these three CDK4/6 inhibitors in less than 4 min is proposed for the first time. Separation was achieved by capillary zone electrophoresis in an acidic medium, in accordance with the structures of the analytes and their pKa values. The optimal pH of the running buffer was found to be 2.9. The optimal method conditions were 27.5 kV separation voltage, 30 °C, 5 s injection time under 50 mbar pressure, and 50 mM phosphate background buffer with benzimidazole as an internal standard. The developed method was validated with respect to robustness, selectivity, accuracy, precision, linearity, and limits of detection. The method was shown to be linear in the range of 10 to 100 µg mL−1 with correlation coefficients higher than 0.9981. A greenness assessment of the proposed method was performed, and the method was shown to be green. The validated method was successfully applied to pharmaceutical dosage forms of all CDK4/6 inhibitors.
Predictive Models of Gas/Particulate Partition Coefficients (KP) for Polycyclic Aromatic Hydrocarbons and Their Oxygen/Nitrogen Derivatives
Authors: Wu Qiang , Cao Siqi , Chen Zhenyi , Wei Xiaoxuan , Ma Guangcai , Yu Haiying
Published: November 2022

Polycyclic aromatic hydrocarbons (PAHs) and their oxygen/nitrogen derivatives released into the atmosphere can alternate between a gas phase and a particulate phase, further affecting their environmental behavior and fate. The gas/particulate partition coefficient (KP) is generally used to characterize such partitioning equilibrium. In this study, the correlation between log KP of fifty PAH derivatives and their n-octanol/air partition coefficient (log KOA) was first analyzed, yielding a strong linear correlation (R2 = 0.801). Then, Gaussian 09 software was used to calculate quantum chemical descriptors of all chemicals at M062X/6-311+G (d,p) level. Both stepwise multiple linear regression (MLR) and support vector machine (SVM) methods were used to develop the quantitative structure-property relationship (QSPR) prediction models of log KP. They yield better statistical performance (R2 > 0.847, RMSE < 0.584) than the log KOA model. Simulation external validation and cross validation were further used to characterize the fitting performance, predictive ability, and robustness of the models. The mechanism analysis shows intermolecular dispersion interaction and hydrogen bonding as the main factors to dominate the distribution of PAH derivatives between the gas phase and particulate phase. The developed models can be used to predict log KP values of other PAH derivatives in the application domain, providing basic data for their ecological risk assessment.