bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization and In Vitro Biocompatibility of Two New Bioglasses for Application in Dental Medicine—A Preliminary Study
Authors: Clichici Andra , Filip Gabriela Adriana , Achim Marcela , Baldea Ioana , Cristea Cecilia , Melinte Gheorghe , Pana Ovidiu , Tudoran Lucian Barbu , Dudea Diana , Stefan Razvan
Published: December 2022

Bioactive glasses (BGs), also known as bioglasses, are very attractive and versatile materials that are increasingly being used in dentistry. For this study, two new bioglasses—one with boron (BG1) and another with boron and vanadium (BG2)—were synthesized, characterized, and tested on human dysplastic keratinocytes. The in vitro biological properties were evaluated through pH and zeta potential measurement, weight loss, Ca2+ ions released after immersion in phosphate-buffered saline (PBS), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) analysis. Furthermore, biocompatibility was evaluated through quantification of lactate dehydrogenase activity, oxidative stress, transcription factors, and DNA lesions. The results indicate that both BGs presented the same behavior in simulated fluids, characterized by high degradation, fast release of calcium and boron in the environment (especially from BG1), and increased pH and zeta potential. Both BGs reacted with the fluid, particularly BG2, with irregular deposits covering the glass surface. In vitro studies demonstrated that normal doses of the BGs were not cytotoxic to DOK, while high doses reduced cell viability. Both BGs induced oxidative stress and cell membrane damage and enhanced NFkB activation, especially BG1. The BGs down-regulated the expression of NFkB and diminished the DNA damage, suggesting the protective effects of the BGs on cell death and efficacy of DNA repair mechanisms.
Innovative Design of Residual Stress and Strain Distributions for Analyzing the Hydrogen Embrittlement Phenomenon in Metallic Materials
Authors: Toribio Jesús , Lorenzo Miguel , Aguado Leticia
Published: December 2022

Round-notched samples are commonly used for testing the susceptibility to hydrogen embrittlement (HE) of metallic materials. Hydrogen diffusion is influenced by the stress and strain states generated during testing. This state causes hydrogen-assisted micro-damage leading to failure that is due to HE. In this study, it is assumed that hydrogen diffusion can be controlled by modifying such residual stress and strain fields. Thus, the selection of the notch geometry to be used in the experiments becomes a key task. In this paper, different HE behaviors are analyzed in terms of the stress and strain fields obtained under diverse loading conditions (un-preloaded and preloaded causing residual stress and strains) in different notch geometries (shallow notches and deep notches). To achieve this goal, two uncoupled finite element (FE) simulations were carried out: (i) a simulation by FE of the loading sequences applied in the notched geometries for revealing the stress and strain states and (ii) a simulation of hydrogen diffusion assisted by stress and strain, for estimating the hydrogen distributions. According to results, hydrogen accumulation in shallow notches is heavily localized close to the wire surface, whereas for deep notches, hydrogen is more uniformly distributed. The residual stress and plastic strains generated by the applied preload localize maximum hydrogen concentration at deeper points than un-preloaded cases. As results, four different scenarios are established for estimating “a la carte” the HE susceptibility of pearlitic steels just combining two notch depths and the residual stress and strain caused by a preload.
Effect of Paste Fluidity and Paste-to-Aggregate Ratio on the Strength and Permeability of Porous Mortar from Manufactured Sand
Authors: Li Weichao , Li Laibo , Li Yali , Li Yanlin , Lu Lingchao , Cheng Xin
Published: December 2022

Many places in the world suffer from a shortage of river sand because of population growth and environmental protection, and people have to replace river sand with manufactured sand (M-sand). In this study, M-sand was adopted as aggregate and the effect of the mix design (paste fluidity (PF) and paste-to-aggregate ratio (P/A)) on the properties of porous mortar was investigated through a combined experimental, statistical and response surface method (RSM). By including variations in both P/A (0.16–0.26) and PF (160–200 mm), the method was utilized to develop ANOVA models and construct response surface and contour lines. The experimental results revealed that the compressive strength of the porous mortar increased by 62.3% to a value of 34.1 MPa while the PF increased to 190 mm from 160 mm at a P/A of 0.20, and the water permeability coefficient was 7.2 mm/s under the same conditions. In addition, the ANOVA analysis of the measured properties revealed a strong interactive effect of the paste-to-aggregate ratio and paste fluidity on the porous mortar properties, and the developed relationship models between the variables and responses were accurate. A porous mortar with a compressive strength over 30 MPa and a permeability coefficient over 7 mm/s could be conveniently designed by RSM. Additionally, the compressive strength of the porous concrete reached more than 40 MPa at a P/A of 0.26.
Effect of the Partial Replacement of Cement with Waste Granite Powder on the Properties of Fresh and Hardened Mortars for Masonry Applications
Authors: Woźniak Zuzanna Zofia , Chajec Adrian , Sadowski Łukasz
Published: December 2022

Granite is a well-known building and decorative material, and, therefore, the amount of produced waste in the form of granite powder is a problem. Granite powder affects the health of people living near landfills. Dust particles floating in the air, which are blown by gusts of wind, can lead to lung silicosis and eye infections, and can also affect the immune system. To find an application for this kind of waste material, it was decided to study the effect of partially replacing cement with waste granite powder on the properties of fresh and hardened mortars intended for masonry applications. The authors planned to replace 5%, 10%, and 15% of cement with waste material. Series of mortar with the addition of granite powder achieved 50% to 70% of the compressive strength of the reference series, and 60% to 76% of the bending strength of the reference series. The partial replacement of cement with the granite powder significantly increased the water sorption coefficient. The consistency of the fresh mortar, and its density and water absorption also increased when compared to the reference series. Therefore, Granite powder can be used as a partial replacement of cement in masonry mortars.
Effect of Volume Fraction of Reinforcement on Microstructure and Mechanical Properties of In Situ (Ti, Nb)B/Ti2AlNb Composites with Tailored Three-Dimensional Network Architecture
Authors: Zhang Ningbo , Ju Boyu , Deng Taiqing , Fu Sen , Duan Cungao , Song Yiwei , Jiang Yijun , Shen Qin , Yao Caogen , Liu Mingda , Wu Ping , Xiu Ziyang , Yang Wenshu
Published: December 2022

The mechanical properties of (Ti, Nb)B/Ti2AlNb composites were expected to improve further by utilizing spark plasma sintering (SPS) and inducing the novel three-dimensional network architecture. In this study, (Ti, Nb)B/Ti2AlNb composites with the novel architecture were successfully fabricated by ball milling the LaB6 and Ti2AlNb mixed powders and subsequent SPS consolidation. The influence of the (Ti, Nb)B content on the microstructure and mechanical properties of the composites was revealed by using the scanning electron microscope (SEM), transmission electron microscopy (TEM) and electronic universal testing machine. The microstructural characterization demonstrated that the boride crystallized into a B27 structure and the α2-precipitated amount increased with the (Ti, Nb)B increasing. When the (Ti, Nb)B content reached 4.9 vol%, both the α2 and reinforcement exhibited a continuous distribution along the prior particle boundaries (PPBs). The tensile test displayed that the tensile strength of the composites presented an increasing trend with the increasing (Ti, Nb)B content followed by a decreasing trend. The composite with a 3.2 vol% reinforcement had the optimal mechanical properties; the yield strengths of the composite at 25 and 650 °C were 998.3 and 774.9 MPa, showing an 11.8% and 9.2% improvement when compared with the Ti2AlNb-based alloy. Overall, (Ti, Nb)B possessed an excellent strengthening effect and inhibited the strength weakening of the PPBs area at high temperatures; the reinforcement content mainly affected the mechanical properties of the (Ti, Nb)B/Ti2AlNb composites by altering the α2-precipitated amount and the morphology of (Ti, Nb)B in the PPBs area. Both the continuous precipitation of the brittle α2 phase and the agglomeration of the (Ti, Nb)B reinforcement dramatically deteriorated the mechanical properties.
An Improved Optimization Model to Predict the MOR of Glulam Prepared by UF-Oxidized Starch Adhesive: A Hybrid Artificial Neural Network-Modified Genetic Algorithm Optimization Approach
Authors: Nazerian Morteza , Karimi Jalal , Torshizi Hossin Jalali , Papadopoulos Antonios N. , Hamedi Sepideh , Vatankhah Elham
Published: December 2022

The purpose of the present article is to study the bending strength of glulam prepared by plane tree (Platanus Orientalis-L) wood layers adhered by UF resin with different formaldehyde to urea molar ratios containing the modified starch adhesive with different NaOCl concentrations. Artificial neural network (ANN) as a modern tool was used to predict this response, too. The multilayer perceptron (MLP) models were used to predict the modulus of rapture (MOR) and the statistics, including the determination coefficient (R2), root mean square error (RMSE), and mean absolute percentage error (MAPE) were used to validate the prediction. Combining the ANN and the genetic algorithm by using the multiple objective and nonlinear constraint functions, the optimum point was determined based on the experimental and estimated data, respectively. The characterization analysis, performed by FTIR and XRD, was used to describe the effect of the inputs on the output. The results indicated that the statistics obtained show excellent MOR predictions by the feed-forward neural network using Levenberg–Marquardt algorithms. The comparison of the optimal output of the actual values obtained by the genetic algorithm resulting from the multi-objective function and the optimal output of the values estimated by the nonlinear constraint function indicates a minimum difference between both functions.
Spectroscopic Ellipsometry Studies on Solution-Processed OLED Devices: Optical Properties and Interfacial Layers
Authors: Gioti Maria
Published: December 2022

Τhe fabrication of organic light-emitting diodes (OLEDs) from solution involves the major problem of stack integrity, setting the determination of the composition and the characteristics of the resulting interfaces prerequisite for the optimization of the growth processes and the achievement of high devices’ performance. In this work, a poly(9,9-dioctylfluorene) (F8) and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) blend is used for the emissive layer (EML), poly-3,4-ethylene dioxythiophene; poly-styrene sulfonate (PEDOT:PSS) is used for a hole transport layer (HTL), and Poly(9,9-bis(3′-(N,N-dimethyl)-N-ethylammoinium-propyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluore-ne))dibromide (PFN-Br) for an electron transport layer (ETL) to produce the OLED device. All the layers are developed using the slot-die process, onto indium tin oxide (ITO)-coated polyethylene terephthalate (PET) flexible substrates, whereas Ag cathode was formed by ink-jet printing under ambient conditions. Spectroscopic ellipsometry measurements were performed upon completion of the successive films’ growth, in sequential steps, for the multilayer OLED development. Ellipsometry analysis using different models demonstrate the degree of intermixing within the layers and provide information about the interfaces. These interfacial properties are correlated with the emission characteristics as well as the final performance of the OLED devices.
Enhanced Short-Term Memory Plasticity of WOx-Based Memristors by Inserting AlOx Thin Layer
Authors: Pyo Juyeong , Ha Hoesung , Kim Sungjun
Published: December 2022

ITO/WOx/TaN and ITO/WOx/AlOx/TaN memory cells were fabricated as a neuromorphic device that is compatible with CMOS. They are suitable for the information age, which requires a large amount of data as next-generation memory. The device with a thin AlOx layer deposited by atomic layer deposition (ALD) has different electrical characteristics from the device without an AlOx layer. The low current is achieved by inserting an ultra-thin AlOx layer between the switching layer and the bottom electrode due to the tunneling barrier effect. Moreover, the short-term memory characteristics in bilayer devices are enhanced. The WOx/AlOx device returns to the HRS without a separate reset process or energy consumption. The amount of gradual current reduction could be controlled by interval time. In addition, it is possible to maintain LRS for a longer time by forming it to implement long-term memory.
Experimental and Numerical Study of Collision Attitude Auxiliary Protection Strategy for Subway Vehicles
Authors: Xu Ping , Yang Liting , Guo Weinian , Yang Chengxing , Che Quanwei , Xu Tuo
Published: December 2022

An auxiliary protection device (rail holding mechanism) was proposed to control the collision attitude of subway vehicles. The dynamics model of head-on collision of subway vehicles was established and verified by the full-scale collision test of the real car; then the force element structure of the rail holding mechanism was equated; finally, the vertical lift and the pitch angle of the three characteristic sections of car body and the wheelsets were used as the evaluation indicators to study the effects of the three design parameters: the gap distance (x1), the linear stage distance (Δ x2) and the stiffness of linear stage (k1). The results show that the linear stage distance has little influence on the collision attitude of the car body, while the x1 and k1 had a greater influence on the collision attitude of the car body. The reasonable reduction of the gap distance x1 and increase the k1 can effectively reduce the vertical lift of the wheelsets and alleviate the nodding phenomenon of the train, and reduce the derailment and jumping phenomenon during the train collision.
A Transferable Thruster Fault Diagnosis Approach for Autonomous Underwater Vehicle under Different Working Conditions with Insufficient Labeled Training Data
Authors: Yin Baoji , Wang Ziwei , Zhang Mingjun , Jin Zhikun , Liu Xing
Published: December 2022

Existing thruster fault diagnosis methods for AUV (autonomous underwater vehicle) usually need sufficient labeled training data. However, it is unrealistic to get sufficient labeled training data for each working condition in practice. Based on this challenge, a transferable thruster fault diagnosis approach is proposed. In the approach, an IPSE (instantaneous power spectrum entropy) and a STNED (signal-to-noise energy difference) are added to SPWVD (smoothed pseudo Wigner-Ville distribution) to identify time and frequency boundaries of the local region in the time-frequency power spectrum caused by thruster fault, forming a TFE (time-frequency energy) method for feature extraction. In addition, the RCQFFV (relative change quantity of the fault feature value), an MSN (multiple scale normalization) and a LSP (least square prediction) are added to SVDD (support vector data description) to align distributions of fault samples, contributing a TSVDD (transferable SVDD) for classification of fault samples. The experimental results of a prototype AUV indicate that the fault feature is monotonic to the percentage of thrust loss for the proposed TFE but not for the SPWVD. The TSVDD has a higher overall classification accuracy in comparison to conventional SVDD under working conditions with no labeled training data.
Design and Analysis of Mechanical Characteristics of EAP Flexible Drivers
Authors: Li Bing , Niu Shaohua , Li Bingyang , Wang Pengfei , Qiao Yuli
Published: December 2022

Electroactive polymer(EAP) is a “smart material” with high energy density, high electromechanical energy conversion efficiency, simple structure, good adaptability to the working environment, etc. It can be made into various shapes to realize flexible drivers. At present, the common EAP actuator is mainly composed of EAP film wound on a spring, and the output performance of this type of actuator is related to the spring stiffness, film prestretching rate, voltage, and other factors. Its working process is actually an electromechanical coupling process. In this paper, two types of cylindrical actuators are designed and tested. The electromechanical coupling mathematical model is constructed to simulate the driver. According to the experimental and simulation results, the relationship between the output displacement and elongation strain of EAP actuator and voltage, spring stiffness, and tensile rate is analyzed. It provides a reference and basis for the design of similar actuators.
Dynamic Analysis of Sigmoid Bidirectional FG Microbeams under Moving Load and Thermal Load: Analytical Laplace Solution
Authors: Attia Mohamed A. , Melaibari Ammar , Shanab Rabab A. , Eltaher Mohamed A.
Published: December 2022

This paper presents for the first time a closed-form solution of the dynamic response of sigmoid bidirectional functionally graded (SBDFG) microbeams under moving harmonic load and thermal environmental conditions. The formulation is established in the context of the modified couple stress theory to integrate the effects of microstructure. On the basis of the elasticity theory, nonclassical governing equations are derived by using Hamilton’s principle in combination with the parabolic higher-order shear deformation theory considering the physical neutral plane concept. Sigmoid distribution functions are used to describe the temperature-dependent thermomechanical material of bulk continuums of the beam in both the axial and thickness directions, and the gradation of the material length scale parameter is also considered. Linear and nonlinear temperature profiles are considered to present the environmental thermal loads. The Laplace transform is exploited for the first time to evaluate the closed-form solution of the proposed model for a simply supported (SS) boundary condition. The solution is verified by comparing the predicted fundamental frequency and dynamic response with the previously published results. A parametric study is conducted to explore the impacts of gradient indices in both directions, graded material length scale parameters, thermal loads, and moving speed of the acted load on the dynamic response of microbeams. The results can serve as a principle for evaluating the multi-functional and optimal design of microbeams acted upon by a moving load.
A Novel Approach to Integrating Uncertainty into a Push Re-Label Network Flow Algorithm for Pit Optimization
Authors: Joshi Devendra , Ali Albahar Marwan , Chithaluru Premkumar , Singh Aman , Yadav Arvind , Miro Yini
Published: December 2022

The standard optimization of open-pit mine design and production scheduling, which is impacted by a variety of factors, is an essential part of mining activities. The metal uncertainty, which is connected to supply uncertainty, is a crucial component in optimization. To address uncertainties regarding the economic value of mining blocks and the general problem of mine design optimization, a minimum-cut network flow algorithm is employed to give the optimal ultimate pit limits and pushback designs under uncertainty. A structure that is computationally effective and can manage the joint presentation and treatment of the economic values of mining blocks under various circumstances is created by the push re-label minimum-cut technique. In this study, the algorithm is put to the test using a copper deposit and shows similarities to other stochastic optimizers for mine planning that have already been created. Higher possibilities of reaching predicted production targets are created by the algorithm’s earlier selection of more certain blocks with blocks of high value. Results show that, in comparison to a conventional approach using the same algorithm, the cumulative metal output is larger when the uncertainty in the metal content is taken into consideration. There is also an additional 10% gain in net present value.
Fracture Process and Failure Mode of Brazilian Discs with Cracks of Different Angles: A Numerical Study
Authors: Luo Xiaoyan , Zhao Guoyan , Xiao Peng , Zhao Wengang
Published: December 2022

In order to determine the effect of internal cracks on the tensile failure of materials, a hybrid finite–discrete element method was used to analyze the Brazilian disc test with cracks of different angles. When the pre-crack angle is between 0° and 60°, the wing crack is initiated from the pre-crack end. When the pre-crack is 90°, the crack initiated from the pre-crack center. When the pre-crack angle is between 0° and 60°, the maximum principal stress and plastic strain are concentrated at the pre-crack end. When the pre-crack angle is 90°, the maximum principal stress and plastic strain are concentrated in the pre-crack center. As the crack angle increased from 0° to 90°, the failure mode of Brazilian discs with cracks transits from splitting into two parts to splitting into four parts. The influence of crack length is further studied. When the crack length is less than 5 mm, the crack angle has little influence on the disc failure mode; Brazilian discs with cracks of different angles undergoes splitting failure along the loading axis. When the crack length is larger than 5 mm, the crack angle has a great effect on the disc failure mode.
Concrelife: A Software to Solve the Chloride Penetration in Saturated and Unsaturated Reinforced Concrete
Authors: Sánchez-Pérez Juan Francisco , Hidalgo Pilar , Alhama Francisco
Published: December 2022

This paper presents new software (Concrelife) capable of reliably simulating chloride ions penetration in reinforced concrete from different environments in the most common 1-D rectangular geometry scenarios. Its numerical solution is obtained from the simulation of models whose structure is based on Network Simulation Method. These models are generated by the program itself and run in the powerful free code NgSpice. The mathematical model of the problem includes the formation of bound chloride, precipitated chloride, reduction of porosity, saturated and unsaturated conditions, etc. All this allows tackling all kinds of scenarios, such as successive changes in concentration and temperature at the boundary, wet-drying cycles, washing of structures, etc. Concrelife has been developed with a pleasant window environment, intuitive and easy for a user not expert in numerical techniques, both for the introduction of data and for the graphic representation of the results, which include the spatial and temporal concentration of all species of chloride, porosity, water content in pores etc. To test and verify the results of the software, applications are presented to real scenarios.
Higher Moments Actually Matter: Spillover Approach for Case of CESEE Stock Markets
Authors: Škrinjarić Tihana
Published: December 2022

The interconnectedness of stock markets is an important topic in empirical research, as spillovers on financial markets matter for asset pricing, portfolio allocation, financial stability, and risk management. This research focuses on all four moments of return distributions on stock markets and their spillovers between CESEE (Central, Eastern, and South-Eastern Europe) stock markets. Higher moments analysis needs to be explored more deeply, but can provide detailed insights into distribution shifts of market returns due to shocks in other markets. This research fills such a gap in the literature by estimating spillover effects between the four moments of stock market return distributions. Based on data from January 2013 to September 2022, the VAR (vector autoregression) model is estimated for individual moments across stock markets as a base for the calculation of spillover indices. The main findings indicate that it is difficult to track all the spillovers at once as the net emitter of shocks to one or other of the countries involved often change to being a net receiver and vice versa. Moreover, higher moments spillovers matter for individual markets, which has important implications for dynamic portfolio selection.
A Memristor-Based Colpitts Oscillator Circuit
Authors: Zhou Ling , You Zhenzhen , Liang Xiaolin , Li Xiaowu
Published: December 2022

This paper investigates a simple memristor emulator consisting of a diode bridge and a capacitor. It exhibits pinched hysteresis loops, and what is more striking is the higher frequency, as it operates up to greater than 5 MHz. Based on the proposed memristor, a higher-frequency Colpitts circuit was established. According to the mathematical model of the system, the system only possesses one unstable equilibrium point. Period doubling bifurcation, reverse periodic doubling bifurcation, different types of periodic and chaotic orbits, transient chaos, coexisting bifurcations and offset boosting are depicted. More interestingly, it has coexisting multiple attractors with different topologies, such as a chaotic attractor accompanied with periodic orbits, period-1 orbits with bicuspid structure and periodic-2 orbits with tridentate structure. Moreover, a hardware circuit using discrete components was fabricated and experimental measurements were consistent with the MATLAB numerical results, further confirming the real feasibility of the proposed circuit.
On Impulsive Implicit ψ-Caputo Hybrid Fractional Differential Equations with Retardation and Anticipation
Authors: Salim Abdelkrim , Alzabut Jehad , Sudsutad Weerawat , Thaiprayoon Chatthai
Published: December 2022

In this paper, we investigate the existence and Ulam–Hyers–Rassias stability results for a class of boundary value problems for implicit ψ-Caputo fractional differential equations with non-instantaneous impulses involving both retarded and advanced arguments. The results are based on the Banach contraction principle and Krasnoselskii’s fixed point theorem. In addition, the Ulam–Hyers–Rassias stability result is proved using the nonlinear functional analysis technique. Finally, illustrative examples are given to validate our main results.
Dynamic ILC for Linear Repetitive Processes Based on Different Relative Degrees
Authors: Wang Lei , Dong Liangxin , Yang Ruitian , Chen Yiyang
Published: December 2022

The current research on iterative learning control focuses on the condition where the system relative degree is equal to 1, while the condition where the system relative degree is equal to 0 or greater than 1 is not considered. Therefore, this paper studies the monotonic convergence of the corresponding dynamic iterative learning controller systematically for discrete linear repetitive processes with different relative degrees. First, a 2D discrete Roesser model of the iterative learning control system is presented by means of 2D systems theory. Then, the monotonic convergence condition of the controlled system is analyzed according to the stability theory of linear repetitive process. Furthermore, the sufficient conditions of the controller existence are given in linear matrix inequality format under different relative degrees, which guarantees the system dynamic performance. Finally, through comparison with static controllers under different relative degrees, the simulation results show that the designed schemes are effective and feasible.
Coefficient Inequalities for Biholomorphic Mappings on the Unit Ball of a Complex Banach Space
Authors: Hamada Hidetaka , Kohr Gabriela , Kohr Mirela
Published: December 2022

In the first part of this paper, we give generalizations of the Fekete–Szegö inequalities for quasiconvex mappings F of type B and the first elements F of g-Loewner chains on the unit ball of a complex Banach space, recently obtained by H. Hamada, G. Kohr and M. Kohr. We obtain the Fekete–Szegö inequalities using the norm under the restrictions on the second and third order terms of the homogeneous polynomial expansions of the mappings F. In the second part of this paper, we give the estimation of the difference of the moduli of successive coefficients for the first elements of g-Loewner chains on the unit disc. We also give the estimation of the difference of the moduli of successive coefficients for the first elements F of g-Loewner chains on the unit ball of a complex Banach space under the restrictions on the second and third order terms of the homogeneous polynomial expansions of the mappings F.
Chitosan-Based Carbon Dots with Applied Aspects: New Frontiers of International Interest in a Material of Marine Origin
Authors: Villalba-Rodríguez Angel M. , González-González Reyna Berenice , Martínez-Ruiz Manuel , Flores-Contreras Elda A. , Cárdenas-Alcaide María Fernanda , Iqbal Hafiz M. N. , Parra-Saldívar Roberto
Published: December 2022

Carbon dots (CDs) have attracted significant research attention worldwide due to their unique properties and advantageous attributes, such as superior optical properties, biocompatibility, easy surface functionalization, and more. Moreover, biomass-derived CDs have attracted much attention because of their additional advantages related to more environmentally friendly and lower-cost synthesis. In this respect, chitosan has been recently explored for the preparation of CDs, which in comparison to other natural precursors exhibited additional advantages. Beyond the benefits related to the eco-friendly and abundant nature of chitosan, using it as a nanomaterial precursor offers additional benefits in terms of structure, morphology, and dopant elements. Furthermore, the high content of nitrogen in chitosan allows it to be used as a single carbon and nitrogen precursor for the preparation of N-doped CDs, significantly improving their fluorescent properties and, therefore, their performances. This review addresses the most recent advances in chitosan-based CDs with a special focus on synthesis methods, enhanced properties, and their applications in different fields, including biomedicine, the environment, and food packaging. Finally, this work also addresses the key challenges to be overcome to propose future perspectives and research to unlock their great potential for practical applications.
Vibration-Assisted Synthesis of Nanoporous Anodic Aluminum Oxide (AAO) Membranes
Authors: Cigane Urte , Palevicius Arvydas , Janusas Giedrius
Published: December 2022

In recent years, many research achievements in the field of anodic aluminum oxide (AAO) membranes can be observed. Nevertheless, it is still an interesting research topic due to its high versatility and applications in various fields, such as template-assisted methods, filtration, sensors, etc. Nowadays, miniaturization is an integral part of different technologies; therefore, research on micro- and nanosized elements is relevant in areas such as LEDs and OLEDs, solar cells, etc. To achieve an efficient mixing process of fluid flow in straight nanopores, acoustofluidic physics has attracted great interest in recent decades. Unfortunately, the renewal of the electrolyte concentration at the bottom of a pore is limited. Thus, excitation is used to improve fluid mixing along nanosized diameters. The effect of excitation by high-frequency vibrations on pore geometry is also investigated. In this study, theoretical simulations were performed. Using theoretical calculations, the acoustic pressure, acoustic velocity, and velocity magnitude were obtained at frequencies of 2, 20, and 40 kHz. Moreover, nanoporous AAO membranes were synthesized, and the influence of high-frequency vibrations on the geometry of the pores was determined. Using a high-frequency excitation of 20 kHz, the thickness of the AAO membrane increased by 17.8%. In addition, the thickness increased by 31.1% at 40 kHz and 33.3% at the resonant frequency of 40 kHz. Using high-frequency vibrations during the anodization process, the electrolyte inside the pores is mixed, and as a result, a higher oxide growth rate and a deeper structure can be achieved. On the other hand, to obtain pores of the same depth, the reaction can be performed in a shorter time.
Design and Development of a Triple-Band Multiple-Input–Multiple-Output Antenna for Sensing Applications
Authors: Raheja Dinesh Kumar , Kumar Sachin , Chakrabartty Shubhro , Kanaujia Binod Kumar
Published: December 2022

In this article, a triple-band quad-element stacked multiple-input–multiple-output (MIMO) antenna is proposed for sensing applications. Each radiating element of the presented MIMO antenna consists of a diagonally truncated square patch, which is proximity coupled to the elliptical radiating patch. The proposed MIMO antenna is designed to resonate for three frequencies (4.2, 4.8, and 5.8 GHz) in the C-band range. The antenna shows circular polarization characteristics at 4.2 and 4.8 GHz frequencies. Each stacked element of the proposed antenna is excited independently through a 50 Ω coaxial feed. The Rogers RT Duroid/5880 dielectric substrate is used for the fabrication of two layers of the stacked MIMO antenna. The presented stacked MIMO antenna simulation and experimental outcomes are in good agreement.
Analysis of Polarization Images in the Microphysical Blood Parameters Research for the Hematocrit Diagnostics
Authors: Khlynov Ruslan D. , Ryzhova Victoria A. , Yarishev Sergey N. , Konyakhin Igor A. , Korotaev Valery V. , Shelepin Yuri E. , Djamiykov Todor S. , Marinov Marin B.
Published: December 2022

The development of non-invasive optoelectronic technologies for human blood monitoring is one of the important research areas for medicine. A critical analysis of optoelectronic methods of blood research and the micromechanical systems based on them is carried out in this article. A design realization of a polarizing portable system for non-invasive monitoring of hematocrit as one of the basic homeostatic constants of the human body containing information about the microphysical parameters of blood cells has been substantiated. A physical model of polarized radiation conversion in a video information system of laser sensing of a biological research object has been formed. Visual and quantitative differences in the spatial distribution of polarization parameters of the scattered radiation for the states of the body with different hematocrit levels have been revealed. A scheme of a multichannel imaging portable system, based on a smartphone using miniature optical and microelectronic components of information conversion for non-invasive monitoring of microphysical blood parameters, has been created. The system implements the principle of polarimetric blood photometry and a multiparametric analysis of the polarization properties of the laser radiation scattered by blood. The developed portable optoelectronic system, based on a smartphone, can be used for rapid blood diagnostics in disaster medicine and the presence of clinical contraindications to the formation of invasive tests. The proposed polarization-based approach is a promising automated alternative to traditional devices and systems for the research of microphysical blood parameters.
An SOI-Structured Piezoresistive Differential Pressure Sensor with High Performance
Authors: Xu Zebin , Yan Jiahui , Ji Meilin , Zhou Yongxin , Wang Dandan , Wang Yuanzhi , Mai Zhihong , Zhao Xuefeng , Nan Tianxiang , Xing Guozhong , Zhang Songsong
Published: December 2022

This paper presents a piezoresistive differential pressure sensor based on a silicon-on-insulator (SOI) structure for low pressure detection from 0 to 30 kPa. In the design phase, the stress distribution on the sensing membrane surface is simulated, and the doping concentration and geometry of the piezoresistor are evaluated. By optimizing the process, the realization of the pressure sensing diaphragm with a controllable thickness is achieved, and good ohmic contact is ensured. To obtain higher sensitivity and high temperature stability, an SOI structure with a 1.5 µm ultra-thin monocrystalline silicon layer is used in device manufacturing. The device diaphragm size is 700 µm × 700 µm × 2.1 µm. The experimental results show that the fabricated piezoresistive pressure sensor has a high sensitivity of 2.255 mV/V/kPa and a sensing resolution of less than 100 Pa at room temperature. The sensor has a temperature coefficient of sensitivity (TCS) of −0.221 %FS/°C and a temperature coefficient of offset (TCO) of −0.209 %FS/°C at operating temperatures ranging from 20 °C to 160 °C. The reported piezoresistive microelectromechanical systems (MEMS) pressure sensors are fabricated on 8-inch wafers using standard CMOS-compatible processes, which provides a volume solution for embedded integrated precision detection applications of air pressure, offering better insights for high-temperature and miniaturized low-pressure sensor research.
Low Profile Meandered Printed Monopole WiMAX/WLAN Antenna for Laptop Computer Applications
Authors: Pandya Killol Vishnuprasad
Published: December 2022

The research on wireless communication demands technology-based efficient radio frequency devices. A printed monopole dual-band antenna is designed and presented. The presented antenna exhibits a promising response with improved bandwidth and gain. The antenna radiates from 3.49 GHz to 3.82 GHz and from 4.83 GHz to 5.08 GHz frequencies with 3.7 dBi and 5.26 dBi gain, having a bandwidth of 9.09% and 5.06%, respectively. The novelty in the developed antenna is that resonating elements have been engineered adequately without the use of the additional reactive component. The cost-effective FR 4 laminate is utilized as a substrate. This structure exhibits an efficiency of over 83% for both resonances. The numerically computed results through simulations and measured results are found to be in good correlation. The aforesaid response from the antenna makes it an appropriate candidate for laptop computer applications.
Recent Progress in Thin-Film Transistors toward Digital, Analog, and Functional Circuits
Authors: Kim Seongjae , Yoo Hocheon
Published: December 2022

Thin-film transistors have been extensively developed due to their process merit: high compatibility with various substrates, large-area processes, and low-cost processes. Despite these advantages, most efforts for thin-film transistors still remain at the level of unit devices, so the circuit level for practical use needs to be further developed. In this regard, this review revisits digital and analog thin-film circuits using carbon nanotubes (CNTs), organic electrochemical transistors (OECTs), organic semiconductors, metal oxides, and two-dimensional materials. This review also discusses how to integrate thin-film circuits at the unit device level and some key issues such as metal routing and interconnection. Challenges and opportunities are also discussed to pave the way for developing thin-film circuits and their practical applications.
Rhizobium pusense-Mediated Selenium Nanoparticles–Antibiotics Combinations against Acanthamoeba sp.
Authors: Nikam Pradnya B. , Salunkhe Jitendra D. , Marathe Kiran R. , Alghuthaymi Mousa A. , Abd-Elsalam Kamel A. , Patil Satish V.
Published: December 2022

Severe ocular infections by Acanthamoeba sp. lead to keratitis, resulting in irreversible vision loss in immune-compromised individuals. When a protozoal infection spreads to neural tissues, it causes granulomatous encephalitis, which can be fatal. Treatment often takes longer due to the transition of amoeba from trophozoites to cyst stages, cyst being the dormant form of Acanthamoeba. A prolonged use of therapeutic agents, such as ciprofloxacin (Cipro), results in severe side effects; thus, it is critical to improve the therapeutic efficacy of these widely used antibiotics, possibly by limiting the drug-sensitive protozoal-phase transition to cyst formation. Owing to the biomedical potential of selenium nanoparticles (SeNPs), we evaluated the synergistic effects of ciprofloxacin and Rhizobium pusense–biogenic SeNPs combination. SeNPs synthesized using Rhizobium pusense isolated from root nodules were characterized using UV–Visible spectrophotometer, FT-IR, SEM with EDX, particle size analysis, and Zeta potential. The combination was observed to reduce the sub-lethal dose of Cipro, which may help reduce its side effects. The selenium and ciprofloxacin (SeNPs–Cipro) combination reduced the LC50 by 33.43%. The anti-protozoal efficacy of SeNPs–Cipro was found to transduce through decreased protozoal-cyst formations and the inhibition of the galactosidase and protease enzymes of trophozoites. Furthermore, high leakage of sugar, proteins, and amino acids during the SeNPs–Cipro treatment was one primary reason for killing the trophozoites. These experimental results may be helpful in the further pre-clinical evaluation of SeNPs–Cipro to combat protozoal infections. Future studies for combinations of SeNPs with other antibiotics need to be conducted to know the potential of SeNPs against antibiotic resistance in Acanthamoeba.
Dietary Fiber Intake and Gut Microbiota in Human Health
Authors: Fu Jiongxing , Zheng Yan , Gao Ying , Xu Wanghong
Published: December 2022

Dietary fiber is fermented by the human gut microbiota, producing beneficial microbial metabolites, such as short-chain fatty acids. Over the last few centuries, dietary fiber intake has decreased tremendously, leading to detrimental alternations in the gut microbiota. Such changes in dietary fiber consumption have contributed to the global epidemic of obesity, type 2 diabetes, and other metabolic disorders. The responses of the gut microbiota to the dietary changes are specific to the type, amount, and duration of dietary fiber intake. The intricate interplay between dietary fiber and the gut microbiota may provide clues for optimal intervention strategies for patients with type 2 diabetes and other noncommunicable diseases. In this review, we summarize current evidence regarding dietary fiber intake, gut microbiota modulation, and modification in human health, highlighting the type-specific cutoff thresholds of dietary fiber for gut microbiota and metabolic outcomes.
Antioxidant Properties and Proximate Composition of Different Tissues of European Beaver
Authors: Florek Mariusz , Domaradzki Piotr , Skałecki Piotr , Stryjecka Małgorzata , Tajchman Katarzyna , Kaliniak-Dziura Agnieszka , Teter Anna , Kędzierska-Matysek Monika
Published: December 2022

The chemical composition, content of cholesterol, retinol and α-tocopherol, and the total antioxidant capacity of different tissues from wild beavers were investigated. The total phenolic contents and free radical scavenging activity (DPPH and ABTS assays) were analysed spectrophotometrically, and fat-soluble vitamins were quantified using high-performance liquid chromatography. The type of tissue (skeletal muscle from loin and hind leg vs. adipose tissue from subcutaneous fat and tail) significantly affected content of all chemical components. The concentration of cholesterol was not related to total fat content. The retinol and α-tocopherol contents (µg/100 g) were significantly higher in the tail (13.0 and 391.2) and subcutaneous fat (12.2 and 371.3) compared to skeletal muscles (as an average 9.1 and 361.4). Among all tissues the tail showed significantly the highest values of DPPH (3.07 mM TE/100 g), ABTS (3.33 mM TE/100 g), and total phenolics (TPC, 543.7 mg GAE/100 g). The concentration of retinol was positively correlated with α-tocopherol (0.748, p < 0.001), and both vitamins were very strongly correlated with DPPH (0.858 and 0.886, p < 0.001), ABTS (0.894 and 0.851, p < 0.001), and TPC (0.666 and 0.913, p < 0.001). The principal component analysis proved that moisture, ash, and protein contents were representative for skeletal muscles, whereas, retinol, α-tocopherol, ABTS and DPPH accurately described the antioxidant capacity of tissue from the tail.
Ursolic Acid Analogs as Potential Therapeutics for Cancer
Authors: Panda Siva S. , Thangaraju Muthusamy , Lokeshwar Bal L.
Published: December 2022

Ursolic acid (UA) is a pentacyclic triterpene isolated from a large variety of vegetables, fruits and many traditional medicinal plants. It is a structural isomer of Oleanolic Acid. The medicinal application of UA has been explored extensively over the last two decades. The diverse pharmacological properties of UA include anti-inflammatory, antimicrobial, antiviral, antioxidant, anti-proliferative, etc. Especially, UA holds a promising position, potentially, as a cancer preventive and therapeutic agent due to its relatively non-toxic properties against normal cells but its antioxidant and antiproliferative activities against cancer cells. Cell culture studies have shown interference of UA with multiple pharmacological and molecular targets that play a critical role in many cells signaling pathways. Although UA is considered a privileged natural product, its clinical applications are limited due to its low absorption through the gastro-intestinal track and rapid elimination. The low bioavailability of UA limits its use as a therapeutic drug. To overcome these drawbacks and utilize the importance of the scaffold, many researchers have been engaged in designing and developing synthetic analogs of UA via structural modifications. This present review summarizes the synthetic UA analogs and their cytotoxic antiproliferative properties reported in the last two decades.
High Performance Marine and Terrestrial Bioadhesives and the Biomedical Applications They Have Inspired
Authors: Melrose James
Published: December 2022

This study has reviewed the naturally occurring bioadhesives produced in marine and freshwater aqueous environments and in the mucinous exudates of some terrestrial animals which have remarkable properties providing adhesion under difficult environmental conditions. These bioadhesives have inspired the development of medical bioadhesives with impressive properties that provide an effective alternative to suturing surgical wounds improving closure and healing of wounds in technically demanding tissues such as the heart, lung and soft tissues like the brain and intestinal mucosa. The Gecko has developed a dry-adhesive system of exceptional performance and has inspired the development of new generation re-usable tapes applicable to many medical procedures. The silk of spider webs has been equally inspiring to structural engineers and materials scientists and has revealed innovative properties which have led to new generation technologies in photonics, phononics and micro-electronics in the development of wearable biosensors. Man made products designed to emulate the performance of these natural bioadhesive molecules are improving wound closure and healing of problematic lesions such as diabetic foot ulcers which are notoriously painful and have also found application in many other areas in biomedicine. Armed with information on the mechanistic properties of these impressive biomolecules major advances are expected in biomedicine, micro-electronics, photonics, materials science, artificial intelligence and robotics technology.
Preparation of a Montmorillonite-Modified Chitosan Film-Loaded Palladium Heterogeneous Catalyst and its Application in the Preparation of Biphenyl Compounds
Authors: Meng Zhifei , Wang Zijian , Li Yu , Li Wei , Zheng Kewang , Xiao Zufeng , Wang Wei , Caiqin Qin
Published: December 2022

The natural polymer chitosan was modified with polyvinyl alcohol to enhance the mechanical properties of the membrane, and then, the montmorillonite-modified chitosan-loaded palladium catalyst was prepared using the excellent coordination properties of montmorillonite. The results showed that the catalyst has good tensile strength, thermal stability, catalytic activity, and recycling performance and is a green catalytic material with industrial application potential.