bluuebunny/crossref_metadata_2025 huggingface dataset:
Geo-Spatial Mapping of Hate Speech Prediction in Roman Urdu
Authors: Aziz Samia , Sarfraz Muhammad Shahzad , Usman Muhammad , Aftab Muhammad Umar , Rauf Hafiz Tayyab
Published: February 2023

Social media has transformed into a crucial channel for political expression. Twitter, especially, is a vital platform used to exchange political hate in Pakistan. Political hate speech affects the public image of politicians, targets their supporters, and hurts public sentiments. Hate speech is a controversial public speech that promotes violence toward a person or group based on specific characteristics. Although studies have been conducted to identify hate speech in European languages, Roman languages have yet to receive much attention. In this research work, we present the automatic detection of political hate speech in Roman Urdu. An exclusive political hate speech labeled dataset (RU-PHS) containing 5002 instances and city-level information has been developed. To overcome the vast lexical structure of Roman Urdu, we propose an algorithm for the lexical unification of Roman Urdu. Three vectorization techniques are developed: TF-IDF, word2vec, and fastText. A comparative analysis of the accuracy and time complexity of conventional machine learning models and fine-tuned neural networks using dense word representations is presented for classifying and predicting political hate speech. The results show that a random forest and the proposed feed-forward neural network achieve an accuracy of 93% using fastText word embedding to distinguish between neutral and politically offensive speech. The statistical information helps identify trends and patterns, and the hotspot and cluster analysis assist in pinpointing Punjab as a highly susceptible area in Pakistan in terms of political hate tweet generation.
Upper Limb Joint Angle Estimation Using Wearable IMUs and Personalized Calibration Algorithm
Authors: Rahman Md. Mahmudur , Gan Kok Beng , Aziz Noor Azah Abd , Huong Audrey , You Huay Woon
Published: February 2023

In physical therapy, exercises improve range of motion, muscle strength, and flexibility, where motion-tracking devices record motion data during exercises to improve treatment outcomes. Cameras and inertial measurement units (IMUs) are the basis of these devices. However, issues such as occlusion, privacy, and illumination can restrict vision-based systems. In these circumstances, IMUs may be employed to focus on a patient’s progress quantitatively during their rehabilitation. In this study, a 3D rigid body that can substitute a human arm was developed, and a two-stage algorithm was designed, implemented, and validated to estimate the elbow joint angle of that rigid body using three IMUs and incorporating the Madgwick filter to fuse multiple sensor data. Two electro-goniometers (EGs) were linked to the rigid body to verify the accuracy of the joint angle measuring algorithm. Additionally, the algorithm’s stability was confirmed even in the presence of external acceleration. Multiple trials using the proposed algorithm estimated the elbow joint angle of the rigid body with a maximum RMSE of 0.46°. Using the IMU manufacturer’s (WitMotion) algorithm (Kalman filter), the maximum RMSE was 1.97°. For the fourth trial, joint angles were also calculated with external acceleration, and the RMSE was 0.996°. In all cases, the joint angles were within therapeutic limits.
A Radial Basis Scale Conjugate Gradient Deep Neural Network for the Monkeypox Transmission System
Authors: Sabir Zulqurnain , Said Salem Ben , Guirao Juan L. G.
Published: February 2023

The motive of this study is to provide the numerical performances of the monkeypox transmission system (MTS) by applying the novel stochastic procedure based on the radial basis scale conjugate gradient deep neural network (RB-SCGDNN). Twelve and twenty numbers of neurons were taken in the deep neural network process in first and second hidden layers. The MTS dynamics were divided into rodent and human, the human was further categorized into susceptible, infectious, exposed, clinically ill, and recovered, whereas the rodent was classified into susceptible, infected, and exposed. The construction of dataset was provided through the Adams method that was refined further by using the training, validation, and testing process with the statics of 0.15, 0.13 and 0.72. The exactness of the RB-SCGDNN is presented by using the comparison of proposed and reference results, which was further updated through the negligible absolute error and different statistical performances to solve the nonlinear MTS.
Stabilization of Nonlinear Vibration of a Fractional-Order Arch MEMS Resonator Using a New Disturbance-Observer-Based Finite-Time Sliding Mode Control
Authors: Alsubaie Hajid , Yousefpour Amin , Alotaibi Ahmed , Alotaibi Naif D. , Jahanshahi Hadi
Published: February 2023

This paper deals with chaos control in an arch microelectromechanical system (MEMS) from the fractional calculus perspective. There is a growing need for effective controllers in various technological fields, and it is important to consider disruptions, uncertainties, and control input limitations when designing a practical controller. To address this problem, we propose a novel disturbance-observer-based terminal sliding mode control technique for stabilizing and controlling chaos in a fractional-order arch MEMS resonator. The design of this technique takes into account uncertainty, disturbances, and control input saturation in the fractional-order system. The proposed control technique is practical for real-world applications because it includes control input saturation. The equation for a fractional-order arch MEMS resonator is presented, and its nonlinear vibration and chaotic behavior are studied. The design process for the proposed control technique is then described. The Lyapunov stability theorem is used to prove the finite-time convergence of the proposed controller and disturbance observer. The proposed controller is applied to the arch MEMS resonator, and numerical simulations are used to demonstrate its effectiveness and robustness for uncertain nonlinear systems. The results of these simulations clearly show the effectiveness of the proposed control technique.
Simple Restricted Modules for the Deformed 𝔟𝔪𝔰3 Algebra
Authors: Chen Qiu-Fan
Published: February 2023

In this paper, we construct a large class of simple restricted modules over the deformed 𝔟𝔪𝔰3 algebra ℬ, which contain the highest weight modules and Whittaker modules. Moreover, we obtain several equivalent statements for simple restricted modules over ℬ.
Saliency Map Estimation Using a Pixel-Pairwise-Based Unsupervised Markov Random Field Model
Authors: Mignotte Max
Published: February 2023

This work presents a Bayesian statistical approach to the saliency map estimation problem. More specifically, we formalize the saliency map estimation issue in the fully automatic Markovian framework. The major and original contribution of the proposed Bayesian–Markov model resides in the exploitation of a pixel pairwise modeling and a likelihood model based on a parametric mixture of two different class-conditional likelihood distributions whose parameters are adaptively and previously estimated for each image. This allows us to adapt our saliency estimation model to the specific characteristics of each image of the dataset and to provide a nearly parameter-free—hence dataset-independent—unsupervised saliency map estimation procedure. In our case, the parameters of the likelihood model are all estimated under the principles of the iterative conditional estimation framework. Once the estimation step is completed, the MPM (maximum posterior marginal) solution of the saliency map (which we show as particularly suitable for this type of estimation), is then estimated by a stochastic sampling scheme approximating the posterior distribution (whose parameters were previously estimated). This unsupervised data-driven Markovian framework overcomes the limitations of current ad hoc or supervised energy-based or Markovian models that often involve many parameters to adapt and that are finely tuned for each different benchmark database. Experimental results show that the proposed algorithm performs favorably against state-of-the-art methods and turns out to be particularly stable across a wide variety of benchmark datasets.
Mathematical Modeling of Air Distribution in Mines Considering Different Ventilation Modes
Authors: Semin Mikhail , Levin Lev
Published: February 2023

The calculation of air distribution in large mine ventilation networks is usually carried out by numerically solving a system of equations representing Kirchhoff’s circuit laws. This formulation of the problem traditionally only considers the frictional air resistance of straight sections of mine airways. However, when analyzing the changing ventilation modes, it is also important to correctly consider the shock losses, which sufficiently affect the redistribution of airflows. The reason is that the shock loss factor strongly depends on the airflow rates at the junctions of mine airways. This paper presents a mathematical model of a ventilation network that considers shock losses. The model considers steady-state air distribution as well as natural draft. The significance of the shock was confirmed with a practical example; we describe the application of the proposed mathematical model for the analysis of air distribution in the ventilation network of a potash mine during planned airflow reversal.
Effect of Methacrylic Acid Monomer on UV-Grafted Polyethersulfone Forward Osmosis Membrane
Authors: A. Aziz S. N. S. , Abu Seman M. N. , Saufi S. M. , Mohammad A. W. , Khayet M.
Published: February 2023

UV irradiation is one of the procedures that has been considered for membrane surface graft polymerization. It is commonly utilized for enhancing the wettability of polyethersulfone (PES) membranes. In this research study, the monomer methacrylic acid (MAA) was used for the UV grafting process of a commercial NF2 PES membrane for the preparation of a forward osmosis (FO) membrane. Three different monomer concentrations and three different UV irradiation times were considered. The intrinsic characteristics of both the surface-modified and pristine membranes were determined via a non-pressurized test method. Compared to the NF2 PES, the surface of the modified membranes was rendered more hydrophilic, as the measured water contact angle was reduced considerably from 65° to 32–58°. The membrane surface modification was also confirmed by the data collected from other techniques, such as atomic force microscopy (AFM), field emission-scanning electron microscope (FESEM) and Fourier-transform infrared spectroscopy–attenuated total reflectance (FTIR–ATR). Additionally, the modified membranes exhibited a greater water permeate flux (Jw) compared to the NF2 PES membrane. In this study, the water permeability (A), solute permeability (B) and structural parameter (S) were determined via a two-stage FO non-pressurized test method, changing the membrane orientation. Compared to the FO pressurized test, smaller S values were obtained with significantly high A and B values for the two non-pressurized tests. The adopted method in the current study is more adequate for determining the intrinsic characteristics of FO membranes.
Wear Mechanism of Fe/Cu Self-Lubricating Composite Coatings Fabricated by Electro-Explosive Spraying under Dry Friction
Authors: Huang Kun , Song Qiuzhi , Chen Pengwan , Liu Ye , Jing Yinping
Published: February 2023

In the present work, Fe/Cu composite coatings were fabricated by electro-explosive spraying technology (EEST), with good lubrication performance and high wear resistance. The microstructure and morphology were characterized by an energy-dispersive spectrometer (EDS), 3D digital microscope, and scanning electron microscope (SEM) coupled with electron backscattered diffraction (EBSD). Mechanical properties and tribological performance were measured using a micro Vickers hardness tester, universal testing machine, and universal friction and wear testing machine. The composite coating had low porosity with a minimum value of 0.7%, high microhardness with a maximum value of 729.9 HV0.2, high bonding strength with a maximum average value of 55.25 MPa, and good wear resistance and self-lubrication, and the ratio of soft metal and hard metal in the coatings was controllable. Under dry friction conditions, the friction reduction mechanism was that there were both metallic oxide particles and soft metal attached in the friction pairs. When the ratio of soft metal in the composite coating was higher, the self-lubricating performance of the coating was better, with adhesive wear as the main wear mechanism; when the ratio of hard metal was higher, the wear resistance was better and the wear mechanism was mainly abrasive wear.
Experimental Study of Stretched Premixed Flame Stabilized in a Flat Channel near a Heated Wall
Authors: Mokrin Sergey , Gubernov Vladimir , Minaev Sergey
Published: February 2023

In this work, the behavior of a lean premixed stretched flame stabilized in a flat channel near a heated wall was studied. Dependences of the flame front position on the stretch rate parameter at temperatures of the heated wall of 1000 and 1200 K and the combustible mixture composition (ϕ = 0.7 and 0.6) were obtained experimentally. The reduced thermal diffusive model was used in numerical simulation for an explanation of obtained experimental results. Theoretical estimates are in qualitative agreement with the experiment. The performed qualitative analysis may be useful in estimation of the combustion product temperature and the residence time of the nanoparticles forming in combustion products before their impact with the hot wall.
Parameters Optimization for Electropolishing Titanium by Using Taguchi-Based Pareto ANOVA
Authors: Prihandana Gunawan Setia , Sriani Tutik , Jamaludin Mohd Fadzil , Yusof Farazila , Arifvianto Budi , Mahardika Muslim
Published: February 2023

Material removal rate in electropolishing is often overlooked because this process generally addressed for surface finish; however, it is paramount on metallic sheet machining possessed with intricate geometry. Electropolishing removes metallic material from the surface of a workpiece based on anodic dissolution process. The material removal rate depends on the current density, electrolyte, the strength of the magnetic field, polishing time and temperature. In this study, three factors of applied voltage, electrolyte composition and magnetic field were evaluated using Taguchi approach to improve the material removal rate in the electropolishing of a pure titanium (99.5%) workpiece. The experiments were undertaken as per Taguchi L9 (33) orthogonal array, and further analyzed using Pareto ANOVA to determine the most significant parameter. It was found that the optimum parametric combination to maximize the material removal rate were, applied voltage of 15 V, ethanol concentration of 20 vol.% and magnetic field of 0.51 T. The experimental results show that the responses in electropolishing process can be improved through this approach.
Effect of the Laser Cladding Parameters on the Crack Formation and Microstructure during Nickel Superalloy Gas Turbine Engines Repair
Authors: Dmitrieva Anastasia , Klimova-Korsmik Olga , Gushchina Marina , Korsmik Rudolf , Zadykyan Grigoriy , Tukov Stepan
Published: February 2023

Cracking of nickel superalloys with a high content of γ’-phase remains an unresolved problem, including in technologies for repairing gas turbine engines blades. Laser cladding is a method of material deposition used to repair parts exposed to aggressive environment and surface wear. Cladding parameters have a high influence on cracking susceptibility nickel superalloys. Alloy ZhS32 has a high propensity for hot cracking when exposed to laser radiation. In this work, the study of the structural and phase features of ZhS32 alloy was carried out. A high tendency to form segregation of refractory elements and carbides in the intergranular areas was found. The features of the structure and phase composition of the material for different cladding parameters were studied. The main contribution of technological parameters to the formation of cracks is shown.
First Observation of Quantum Diffusion in Non-Cubic Metal: Deuterium Diffusion in In
Authors: Vykhodets Vladimir , Nefedova Olga , Kurennykh Tatiana , Vykhodets Evgenia
Published: February 2023

Diffusion of deuterium in indium is studied herein. In the temperature range 200–350 K, mass transfer is controlled predominantly by the mechanism of overbarrier atomic jumps; at temperatures from 80 to 120 K, by tunneling; whereas in the range from 120 to 200 K, there takes place a gradual transition from one migration mechanism to the other. These results are of fundamental significance since it is shown for the first time that quantum diffusion can be observed in a metal with a crystal lattice other than the body centered cubic one. Conditions are specified that are necessary for the observation of quantum diffusion of hydrogen: low values of Debye temperature, density of atomic packing in the lattice, and distance between the nearest equilibrium positions of hydrogen atoms. Moreover, data on the influence of point defects on hydrogen tunneling in solids are gained for the first time as well. The quantum diffusion coefficient is twice as high in the sample with enhanced vacancy concentration.
Copper Electrowinning from Supercritical Leachate of Printed Circuit Boards
Authors: Calgaro Camila Ottonelli , da Silva Maurício Dalla Costa Rodrigues , Tanabe Eduardo Hiromitsu , Bertuol Daniel Assumpção
Published: February 2023

The technological development propitiates the rapid replacement of electrical and electronic equipment, which makes it indispensable to develop recycling processes for the treatment of this equipment when discarded. Printed circuit boards (PCBs) are fundamental components of electrical and electronic equipment. PCBs are composed of ceramics, polymers, and metals. Copper is the metal that is present in the greatest percentage of mobile phone PCBs. The objective of this study was to recover copper in the form of metallic deposits from a copper solution extracted from comminuted PCBs through supercritical CO2 in the presence of cosolvents (H2O2 and H2SO4). A synthetic CuSO4 solution was employed to determine the ideal current density in the range of 250 to 540 A/m2. The electrowinning of the leachate solution from PCBs was performed at the determined current density. Using the current density of 250 A/m2, pH equal to 4, and temperature of 25 °C, a current efficiency of around 100% was achieved for the real solution. The deposit obtained showed a copper concentration of 95.97 wt%, recovering 40% of the copper contained in the solution in 300 min of electrowinning. It was observed that for a longer electrowinning time, the percentage of copper recovery could increase.
Optimization of Thick 22MnB5 Sheet Steel Part Performance through Laser Tempering
Authors: Garcia-Llamas Eduard , Pujante Jaume , Frómeta David , Corón David , Galceran Laura , Golling Stefan , Seijas Carlos , Casellas Daniel
Published: February 2023

Press Hardening offers the possibility to obtain a wide range of mechanical properties through microstructural tailoring. This strategy has been successfully applied in thin sheet components, for instance, through differential cooling strategies. The application of these added value features to truck components implies adapting the process to the manufacture of thick sheet metal. This introduces an additional layer of complexity, but also opportunity, in a process where the final microstructure and, thus the mechanical performance is generated in the press shop. This work presents a study on optimizing the crash worthiness and impact energy absorption on a press hardened thick 22MnB5 steel sheet. Different microstructure design strategies have been studied, including ferrite-Pearlite (representative of a differential heating and austenitization strategy), in-die generated Bainite (representative of differential cooling) and Tempered Martensite (generated through laser tempering), keeping a fully hardened martensite as a reference condition. The material performance has been compared in terms of the monotonic properties, useful for anti-intrusion performance, and Essential Work of Fracture, a well-suited parameter to predict the crash failure behavior of high strength steels. The results show that laser tempering offers properties similar to Bainite-based microstructures and can be a successful replacement in components where the sheet thickness does not allow for the fine control of the in-die thermomechanical evolution.
Alterations of NMR-Based Lipoprotein Profile Distinguish Unstable Angina Patients with Different Severity of Coronary Lesions
Authors: Ye Yongxin , Fan Jiahua , Chen Zhiteng , Li Xiuwen , Wu Maoxiong , Liu Wenhao , Zhou Shiyi , Rasmussen Morten Arendt , Engelsen Søren Balling , Chen Yangxin , Khakimov Bekzod , Xia Min
Published: February 2023

Non-invasive detection of unstable angina (UA) patients with different severity of coronary lesions remains challenging. This study aimed to identify plasma lipoproteins (LPs) that can be used as potential biomarkers for assessing the severity of coronary lesions, determined by the Gensini score (GS), in UA patients. We collected blood plasma from 67 inpatients with angiographically normal coronary arteries (NCA) and 230 UA patients, 155 of them with lowGS (GS ≤ 25.4) and 75 with highGS (GS > 25.4), and analyzed it using proton nuclear magnetic resonance spectroscopy to quantify 112 lipoprotein variables. In a logistic regression model adjusted for four well-known risk factors (age, sex, body mass index and use of lipid-lowering drugs), we tested the association between each lipoprotein and the risk of UA. Combined with the result of LASSO and PLS-DA models, ten of them were identified as important LPs. The discrimination with the addition of selected LPs was evaluated. Compared with the basic logistic model that includes four risk factors, the addition of these ten LPs concentrations did not significantly improve UA versus NCA discrimination. However, thirty-two selected LPs showed notable discrimination power in logistic regression modeling distinguishing highGS UA patients from NCA with a 14.9% increase of the area under the receiver operating characteristics curve. Among these LPs, plasma from highGS patients was enriched with LDL and VLDL subfractions, but lacked HDL subfractions. In summary, we conclude that blood plasma lipoproteins can be used as biomarkers to distinguish UA patients with severe coronary lesions from NCA patients.
Metabolomics-Based Profiling via a Chemometric Approach to Investigate the Antidiabetic Property of Different Parts and Origins of Pistacia lentiscus L.
Authors: Sehaki Chabha , Molinie Roland , Mathiron David , Fontaine Jean-Xavier , Jullian Nathalie , Ayati Fadila , Fernane Farida , Gontier Eric
Published: February 2023

Pistacia lentiscus L. is a medicinal plant that grows spontaneously throughout the Mediterranean basin and is traditionally used to treat diseases, including diabetes. The aim of this work consists of the evaluation of the α-glucosidase inhibitory effect (i.e., antidiabetic activity in vitro) of different extracts from the leaves, stem barks and fruits of P. lentiscus harvested on mountains and the littoral of Tizi-Ouzou in Algeria. Metabolomic profiling combined with a chemometric approach highlighted the variation of the antidiabetic properties of P. lentiscus according to the plant’s part and origin. A multiblock OPLS analysis showed that the metabolites most involved in α-glucosidase inhibition activity were mainly found in the stem bark extracts. The highest inhibitory activity was found for the stem bark extracts, with averaged inhibition percentage values of 84.7% and 69.9% for the harvested samples from the littoral and mountain, respectively. On the other hand, the fruit extracts showed a lower effect (13.6%) at both locations. The UHPLC-ESI-HRMS characterization of the metabolites most likely responsible for the α-glucosidase-inhibitory activity allowed the identification of six compounds: epigallocatechin(4a>8)epigallocatechin (two isomers), (epi)gallocatechin-3′-O-galloyl-(epi)gallocatechin (two isomers), 3,5-O-digalloylquinic acid and dihydroxy benzoic acid pentoside.
Easy-to-Assembly System for Decellularization and Recellularization of Liver Grafts in a Bioreactor
Authors: Borges Maurício Felisberto , Maurmann Natasha , Pranke Patricia
Published: February 2023

Decellularization of organs creates an acellular scaffold, ideal for being repopulated by cells. In this work, a low-cost perfusion system was created to be used in the process of liver decellularization and as a bioreactor after recellularization. It consists of a glass chamber to house the organ coupled to a peristaltic pump to promote liquid flow through the organ vascular tree. The rats’ liver decellularization was made with a solution of sodium dodecyl sulfate. The recellularization was made with 108 mesenchymal stromal/stem cells and cultivated for seven days. The decellularized matrices showed an absence of DNA while preserving the collagen and glycosaminoglycans quantities, confirming the efficiency of the process. The functional analyses showed a rise in lactate dehydrogenase levels occurring in the first days of the cultivation, suggesting that there is cell death in this period, which stabilized on the seventh day. Histological analysis showed conservation of the collagen web and some groups of cells next to the vessels. It was possible to establish a system for decellularization and a bioreactor to use for the recellularization method. It is easy to assemble, can be ready to use in little time and be easily sterilized.
An Electromagnetic-Driven Microshutter Array in a Field-of-View Gated Image System for All-Time Star Sensors
Authors: Fang Liang , Wang Weimin , Wang Qiang , Tan Shuliang , Zhang Hui , Zhao Rujin , Liu Enhai
Published: February 2023

Aiming at the application requirements of a field of view (FOV) gated imaging system for all-time star sensors, a key device of a microshutter array with large unit size, high duty cycle, and fast response speed based on the electromagnetic actuation is designed. The proposed microshutter array adopts the principle that the current-carrying coil is subjected to the magnetic force in the magnetic field. The coil element is deflected by the loading current and acts as a light barrier in realizing the optical switch function. The effects of the coil element parameters on the magnetic force torque, torsion beam resistance torque, and switch response time are analyzed, and the structural parameters of the coil element are determined. A sample of the proposed microshutter array based on the electromagnetic actuation with a 4-mm period and a 2.8-mm aperture is fabricated and tested. The test results demonstrate the good switching function of the proposed microshutter array and show that the switch response time of the microshutter element is approximately 2.5 ms. This proposed microshutter array is used to gate an instantaneous small FOV to suppress the sky’s background radiation and make a FOV-gated imaging system realize the multi-stars detection by switching the gated FOV rapidly. This will solve the problem that only one star can be detected within the FOV by a traditional all-time star tracker and promote the all-time star sensor to realize star pattern recognition and autonomous astronomical navigation in the daytime.
Nanoparticle Printing for Microfluidic Applications: Bipolar Electrochemistry and Localized Raman Sensing Spots
Authors: Broccoli Alessia , Vollertsen Anke R. , Roels Pauline , van Vugt Aaike , van den Berg Albert , Odijk Mathieu
Published: February 2023

The local integration of metal nanoparticle films on 3D-structured polydimethylsiloxane (PDMS)-based microfluidic devices is of high importance for applications including electronics, electrochemistry, electrocatalysis, and localized Raman sensing. Conventional processes to locally deposit and pattern metal nanoparticles require multiple steps and shadow masks, or access to cleanroom facilities, and therefore, are relatively imprecise, or time and cost-ineffective. As an alternative, we present an aerosol-based direct-write method, in which patterns of nanoparticles generated via spark ablation are locally printed with sub-mm size and precision inside of microfluidic structures without the use of lithography or other masking methods. As proof of principle, films of Pt or Ag nanoparticles were printed in the chambers of a multiplexed microfluidic device and successfully used for two different applications: Screening electrochemical activity in a high-throughput fashion, and localized sensing of chemicals via surface-enhanced Raman spectroscopy (SERS). The versatility of the approach will enable the generation of functional microfluidic devices for applications that include sensing, high-throughput screening platforms, and microreactors using catalytically driven chemical conversions.
Data and Service Security of GNSS Sensors Integrated with Cryptographic Module
Authors: Xu Changhui , Zhang Jingkui , Zhang Zhiyou , Hou Jianning , Wen Xujie
Published: February 2023

Navigation and positioning are of increasing importance because they are becoming a new form of infrastructure. To ensure both development and security, this study designed a technical innovation structure to upgrade the GNSS (Global Navigation Satellite System) data transmission and real-time differential correction service system and proposed a new multiple cryptographic fusion algorithm to achieve the encryption and decryption of GNSS data and services. First, a GNSS station encrypts GNSS data with an encryption key and obtains a public key from a GNSS data center to encrypt the GNSS data encryption key. After that, identity authentication of a GNSS station is carried out, and an SSL VPN is established between the GNSS station and a GNSS data center before GNSS data are transmitted to the GNSS data center. Then, the GNSS data center decrypts the received GNSS data. The process of an intelligent terminal for real-time differential corrections is similar to that of the GNSS station and the GNSS data center. A GNSS sensor integrated with a cryptographic module was developed to validate the structure in an open environment. The results showed that the developed GNSS sensor was successful in encrypting the data, and the GNSS data center was able to decrypt the data correctly. For the performance test, a cryptography server was able support the requirements of GNSS applications. However, a cryptography server was optimal in supporting 40~50 GNSS stations simultaneously, whereas a cluster was suggested to be configured if the number of GNSS stations was more than 60. In conclusion, the method was able to ensure the validity, confidentiality, integrity, and non-repudiation of GNSS data and services. The proposed upgrading technology was suitable for coordinating GNSS development and security.
Simulation of the Irradiation Cascade Effect of 6H-SiC Based on Molecular Dynamics Principles
Authors: Chen Yaolin , Liu Hongxia , Gao Tianzhi , Wei Hao
Published: February 2023

When semiconductor materials are exposed to radiation fields, cascade collision effects may form between the radiation particles in the radiation field and the lattice atoms in the target material, creating irradiation defects that can lead to degradation or failure of the performance of the device. In fact, 6H-SiC is one of the typical materials for third-generation broadband semiconductors and has been widely used in many areas of intense radiation, such as deep space exploration. In this paper, the irradiation cascade effect between irradiated particles of different energies in the radiation and lattice atoms in 6H-SiC target materials is simulated based on the molecular dynamics analysis method, and images of the microscopic trajectory evolution of PKA and SKA are obtained. The recombination rates of the Frenkel pairs were calculated at PKA energies of 1 keV, 2 keV, 5 keV, and 10 keV. The relationship between the number of defects, the spatial distribution pattern of defects, and the clustering of defects in the irradiation cascade effect of 6H-SiC materials with time and the energy of PKA are investigated. The results show that the clusters are dominated by vacant clusters and are mainly distributed near the trajectories of the SKA. The number and size of vacant clusters, the number of Frenkel pairs, and the intensity of cascade collisions of SKAs are positively correlated with the magnitude of the energy of the PKA. The recombination rate of Frenkel pairs is negatively correlated with the magnitude of the energy of PKA.
Novel Microwave Synthesis of Copper Oxide Nanoparticles and Appraisal of the Antibacterial Application
Authors: Rajamohan Rajaram , Raorane Chaitany Jayprakash , Kim Seong-Cheol , Ashokkumar Sekar , Lee Yong Rok
Published: February 2023

The exceptional characteristics of bio-synthesized copper oxide nanoparticles (CuO NPs), including high surface-to-volume ratio and high-profit strength, are of tremendous interest. CuO NPs have cytotoxic, catalytic, antibacterial, and antioxidant properties. Fruit peel extract has been recommended as a valuable alternative method due to the advantages of economic prospects, environment-friendliness, improved biocompatibility, and high biological activities, such as antioxidant and antimicrobial activities, as many physical and chemical methods have been applied to synthesize metal oxide NPs. In the presence of apple peel extract and microwave (MW) irradiation, CuO NPs are produced from the precursor CuCl2. 2H2O. With the help of TEM analysis, and BET surface area, the average sizes of the obtained NPs are found to be 25–40 nm. For use in antimicrobial applications, CuO NPs are appropriate. Disk diffusion tests were used to study the bactericidal impact in relation to the diameter of the inhibition zone, and an intriguing antibacterial activity was confirmed on both the Gram-positive bacterial pathogen Staphylococcus aureus and Gram-negative bacterial pathogen Escherichia coli. Moreover, CuO NPs did not have any toxic effect on seed germination. Thus, this study provides an environmentally friendly material and provides a variety of advantages for biomedical applications and environmental applications.
Effects of Cr Stress on Bacterial Community Structure and Composition in Rhizosphere Soil of Iris tectorum under Different Cultivation Modes
Authors: Wei Zhao , Sixi Zhu , Baojing Gu , Xiuqing Yang , Guodong Xia , Baichun Wang
Published: February 2023

With the rapid development of industry, Cr has become one of the major heavy metal pollutants in soil, severely impacting soil microecology, among which rhizosphere microorganisms can improve the soil microenvironment to promote plant growth. However, how rhizosphere bacterial communities respond to Cr stress under different cultivation modes remains to be further studied. Therefore, in this study, a greenhouse pot experiment combined with 16S rRNA high-throughput sequencing technology was used to study the effects of Cr stress at 200 mg kg−1 on the bacterial community structure and diversity in the rhizosphere soil of Iris tectorum under different cultivation modes. The results showed that the rhizosphere bacterial community diversity index (Shannon and Simpson) and abundance index (Ace and Chao) increased significantly with wetland plant diversity under Cr stress. Moreover, the bacterial community changed by 20.1% due to the addition of Cr, further leading to a 15.9% decrease in the common species of the bacterial community, among which Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteriota accounted for more than 74.8% of the total sequence. However, with the increase in plant diversity, the abundance of rhizosphere-dominant bacteria and plant growth-promoting bacteria communities increased significantly. Meanwhile, the symbiotic network analysis found that under the two cultivation modes, the synergistic effect between the dominant bacteria was significantly enhanced, and the soil microenvironment was improved. In addition, through redundancy analysis, it was found that C, N, and P nutrients in uncontaminated soil were the main driving factors of bacterial community succession in the rhizosphere of I. tectorum, and Cr content in contaminated soil was the main driving factor of bacterial community succession in I. tectorum rhizosphere. In summary, the results of this study will provide a basis for the response of the rhizosphere bacterial community to Cr and the interaction between wetland plants and rhizosphere bacteria in the heavy metal restoration of wetland plants under different cultivation modes.
The Stability of Anthocyanins and Their Derivatives through Clay Minerals: Revising the Current Literature
Authors: Cunha Robson , Trigueiro Pollyana , Orta Cuevas María del Mar , Medina-Carrasco Santiago , Duarte Thiago M. , Honório Luzia M. de C. , Damacena Dihêgo H. L. , Fonseca Maria Gardennia , da Silva-Filho Edson C. , Osajima Josy A.
Published: February 2023

In recent years, anthocyanins, natural dyes, have promoted great scientific and technological interest. Their intrinsic antioxidant properties and health benefits make them ideal representatives of natural dyes as replacements for synthetic dyes. However, their instability can limit their use. A promising strategy to increase the color stability of anthocyanins is their interaction with clay minerals structures. Clay minerals have characteristics favorable to the stabilization of natural dyes, such as adsorption capacity, good surface chemistry, ion exchange capacity, abundance, non-toxicity, and environmental compatibility. This review summarizes relevant works that present different clays or clay minerals as robust inorganic matrices for incorporation, improved stability, and increased resistance against the thermal- and photodegradation of anthocyanins. In addition, several authors propose different applications for the formed anthocyanin-based hybrids.
Effect of Long-Term Stockpiling on Oxidation and Flotation Response of Low-Grade Copper Sulphide Ore
Authors: Tavares Aline Cristina , Monte Marisa Bezerra de Mello , Tavares Luís Marcelo
Published: February 2023

Since the start-up of the Sossego copper concentrator, located in the Carajás Mineral Province in the southeast of Para State, Brazil, the low-grade ore (~0.34% Cu) has been stockpiled, as defined in the long-term mine plan, to be reclaimed at the end of the mine life. Given this imminent need to process around 40 Mt of this low-grade ore, questions have been raised related to the extent of oxidation that might have occurred in this stockpiled ore. In this context, a study was designed to characterize the stockpiled ore and assess the effect of the ore oxidation on its flotation response. A sampling campaign of the stockpiled ore was carried out to analyze the main variables that could influence the level of oxidation, and, consequently, copper recovery, such as stockpiling time, depth, and particle size. The results showed that there are two main factors negatively impacting the copper recovery of the low-grade stockpiled ore: the surface oxidation and the level of liberation of the copper mineral. Depth and period of stockpiling were not found to influence the level of oxidation, nor the flotation response. An empirical model was proposed for the copper recovery in the rougher stage, which resulted in a predicted value of 90.7%, which was lower than that for the fresh (and higher copper content) ore fed to the plant (93%).
Intercalation of Nontronite Clays from Santa Elena, Ecuador, Using Different Surfactant Hydrophobicity
Authors: Rigail-Cedeño Andres F. , Cornejo Mauricio H. , Cáceres-Zambrano Julio A. , Alava-Rosado Johanna S. , García-Mejía Gladys
Published: February 2023

The research of organoclays has been occurring for many years to develop and add value to these inorganic materials for several industrial applications, such as pollutant absorbers or impermeable plastics. The organoclay applications are intrinsically related to organo-modification and the structure of clays. This study shows the preparation and characterization of organoclays produced by a nontronite type clay (calcic bentonite) from the Tosagua Formation in the peninsula of Santa Elena in Ecuador. These clays were purified and centrifuged before organo-treatment. The purification and separation processes were used to remove organic matter and carbonates, and a cationic interchange from calcic to sodic (Ca2+ to Na+) was carried out. Organo-modification was performed using two types of cationic compounds, i.e., Oleylmethylbis (2-hydroxyethyl) ammonium chloride and Di (hydrogenated tallow alkyl) quaternary amine to organoclay with different surface hydrophobicity. The samples were characterized by X-ray diffractometry (XRD), infrared spectrometry (FT-IR), thermo-gravimetry (TGA), and scanning electron microscopy (SEM) to analyze the effect after the mentioned treatment and the resulting organoclays by the addition of these surfactants. The results confirm the significant intercalation of the organic treatment suitable for environmental remediation, compatibilizing recycled plastics, or improving performance in different hydrophobicity systems for industrial applications.
Structural and Molecular Basis for Mitochondrial DNA Replication and Transcription in Health and Antiviral Drug Toxicity
Authors: Park Joon , Baruch-Torres Noe , Yin Y. Whitney
Published: February 2023

Human mitochondrial DNA (mtDNA) is a 16.9 kbp double-stranded, circular DNA, encoding subunits of the oxidative phosphorylation electron transfer chain and essential RNAs for mitochondrial protein translation. The minimal human mtDNA replisome is composed of the DNA helicase Twinkle, DNA polymerase γ, and mitochondrial single-stranded DNA-binding protein. While the mitochondrial RNA transcription is carried out by mitochondrial RNA polymerase, mitochondrial transcription factors TFAM and TFB2M, and a transcription elongation factor, TEFM, both RNA transcriptions, and DNA replication machineries are intertwined and control mtDNA copy numbers, cellular energy supplies, and cellular metabolism. In this review, we discuss the mechanisms governing these main pathways and the mtDNA diseases that arise from mutations in transcription and replication machineries from a structural point of view. We also address the adverse effect of antiviral drugs mediated by mitochondrial DNA and RNA polymerases as well as possible structural approaches to develop nucleoside reverse transcriptase inhibitor and ribonucleosides analogs with reduced toxicity.
Electrochemical Epoxidation Catalyzed by Manganese Salen Complex and Carbonate with Boron-Doped Diamond Electrode
Authors: Roy Pijush Kanti , Amanai Keisuke , Shimizu Ryosuke , Kodera Masahito , Kurahashi Takuya , Kitayama Kenji , Hitomi Yutaka
Published: February 2023

Epoxides are essential precursors for epoxy resins and other chemical products. In this study, we investigated whether electrochemically oxidizing carbonate ions could produce percarbonate to promote an epoxidation reaction in the presence of appropriate metal catalysts, although Tanaka and co-workers had already completed a separate study in which the electrochemical oxidation of chloride ions was used to produce hypochlorite ions for electrochemical epoxidation. We found that epoxides could be obtained from styrene derivatives in the presence of metal complexes, including manganese(III) and oxidovanadium(IV) porphyrin complexes and manganese salen complexes, using a boron-doped diamond as the anode. After considering various complexes as potential catalysts, we found that manganese salen complexes showed better performance in terms of epoxide yield. Furthermore, the substituent effect of the manganese salen complex was also investigated, and it was found that the highest epoxide yields were obtained when Jacobsen’s catalyst was used. Although there is still room for improving the yields, this study has shown that the in situ electrochemical generation of percarbonate ions is a promising method for the electrochemical epoxidation of alkenes.
Effects of CeO2 Nanoparticles on Nutritional Quality of Two Crop Plants, Corn (Zea mays L.) and Soybean (Glycine max L.)
Authors: Gui Xin , Dong Chaonan , Fan Shixian , Jiao Chunlei , Song Zhuda , Shen Jiaqi , Zhao Yong , Li Xuanzhen , Zhang Fawen , Ma Yuhui , He Xiao , Lin Aijun , Zhang Zhiyong
Published: February 2023

With the widespread applications of manufactured nanoparticles (NPs), there are increasing concerns about their potential adverse effects on the environment and living systems. Many studies demonstrated that NPs could significantly affect the growth and development of crop plants. However, knowledge regarding the impacts of NPs on crop quality is rather limited. In this study, the effects of CeO2 NPs (25, 75, and 225 mg Ce/kg) and CeCl3 (25 mg Ce/kg) on the nutritional components of soil-cultivated corn and soybean plants were evaluated. Both treatments tended to decrease the dry weight of grain per plant, while only 225 mg/kg CeO2 NPs on soybean and CeCl3 on corn showed statistical significance compared with the respective control. CeO2 NPs at 225 mg/kg significantly decreased the content of starch in the corn kernels by 18.2% but increased total phenols in soybean seeds by 18.4%. Neither CeO2 NPs nor CeCl3 significantly affected the contents of minerals in corn kernels except for Zn. However, in the case of soybean, the two treatments tended to decrease the contents of P, Zn, Mn, and Mo but increase the content of S. Overall, the results suggest that CeO2 NPs and Ce3+ ions showed similar but not identical effects on corn and soybean plants. CeO2 NPs affect the nutritional quality of crop plants in a species-dependent manner.
Orbital Polarization-Dependent Fragment Twist-Induced Intramolecular Electric-Field-Driven Charge Transfer
Authors: Bo Wenjing , Sheng Hao , Wang Jingang
Published: February 2023

Defects, such as twisting, in fused aromatic hydrocarbons disrupt the plane of the π orbital. The twisted structure induces an electric field in the system and affects the spectra. In this work, theoretical studies show that the intramolecular electric field within a distinctly twisted structure is larger than that of other molecules. In addition, the spectral study shows that the degree of charge transfer and the magnetic transition dipole in the electrostatic potential extremum region of the molecular electric field were significantly improved, which affected the optical absorption and chiral optical behavior of the molecule. The discovery of this theoretical regulation law will provide a solid foundation for the electric-field-induced regulation of optical properties and will promote the precise design and synthesis of optoelectronic molecules with inner electric fields.