bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Single-Point Incremental Forming of Polymer Sheets through FEM
Authors: Formisano Antonio , Boccarusso Luca , Durante Massimo
Published: January 2023

Incremental sheet forming represents a relatively new process appointed to form sheets of pure metals, alloys, polymers, and composites for the manufacture of components in fields where customized production in a short time and at a low cost is required. Its most common variant, named single-point incremental forming, is a flexible process using very simple tooling; the sheet is clamped along the edges and a hemispherical-headed tool follows a required path, to deform the sheet locally. In so doing, better formability is reached without any dedicated dies and for low-forming forces, which represent some of the attractive features of this process. Nevertheless, and with special reference to thermoplastic sheets, incremental formed parts suffer from peculiar defects like twisting and wrinkling. In this numerical work, analyses were conducted through a commercial finite element code by varying the toolpath strategy of the incremental forming of polycarbonate sheets. The investigation of some features like the forming forces, the deformation states, the energy levels, and the forming time was carried out, to determine the toolpath strategy able to optimize the incremental forming process of polymer sheets. The results of the numerical analyses highlight a reduction of the forming forces when using toolpaths alternating diagonal up and vertical down steps and, presumably, a reduced risk of failures and defects. Furthermore, these toolpath strategies solutions also have a positive impact on the environment in terms of energy and do not significantly increase the manufacturing time.
Structural, Magnetic and Vibrational Properties of Van Der Waals Ferromagnet CrBr3 at High Pressure
Authors: Lis Olga , Kozlenko Denis , Kichanov Sergey , Lukin Evgenii , Zel Ivan , Savenko Boris
Published: January 2023

The crystal and magnetic structures of van der Waals layered ferromagnet CrBr3 were studied using X-ray powder diffraction and neutron powder diffraction at pressures up to 23 GPa at ambient temperature and up to 2.8 GPa in the temperature range 6–300 K, respectively. The vibration spectra of CrBr3 were studied using Raman spectroscopy at pressures up to 23 GPa at ambient temperature. The anomalous pressure behavior of structural parameters and vibrational modes was observed, associated with a gradual isostructural phase transition in the pressure range 2.5–7 GPa. The Curie temperature TC reduced rapidly with a pressure coefficient dTC/dP=−4.1(4) K/GPa. A full suppression of the ferromagnetic state was expected at PC~8.4 GPa, where onset of the antiferromagnetic spin arrangement or magnetically disordered state may take place. Anomalies in Raman spectra at P~15 GPa point to another possible phase transformation in CrBr3, which may be related to the proximity of metallization of this van der Waals ferromagnet.
Formic Acid Dehydrogenation over Ru- and Pd-Based Catalysts: Gas- vs. Liquid-Phase Reactions
Authors: Ruiz-López Estela , Ribota Peláez María , Blasco Ruz María , Domínguez Leal María Isabel , Martínez Tejada Marcela , Ivanova Svetlana , Centeno Miguel Ángel
Published: January 2023

Formic acid has recently been revealed to be an excellent hydrogen carrier, and interest in the development of efficient and selective catalysts towards its dehydrogenation has grown. This reaction has been widely explored using homogeneous catalysts; however, from a practical and scalable point of view, heterogeneous catalysts are usually preferred in industry. In this work, formic acid dehydrogenation reactions in both liquid- and vapor-phase conditions have been investigated using heterogeneous catalysts based on mono- or bimetallic Pd/Ru. In all of the explored conditions, the catalysts showed good catalytic activity and selectivity towards the dehydrogenation reaction, avoiding the formation of undesired CO.
Enhanced Ferroelectric and Dielectric Properties of Niobium-Doped Lead-Free Piezoceramics
Authors: Naeem Faysal , Saleem Mohsin , Jabbar Hamid , Tanvir Gulraiz , Asif Fiza , Baluch Abrar H. , Irfan Muhammad , Ghaffar Abdul , Maqbool Adnan , Rafiq Tayyab
Published: January 2023

Lead-free ceramics are promising candidates for replacing lead-based piezoelectric materials such as lead-zirconate-titanate (PZT) if they can compete in dielectric and ferroelectric characteristics. In this work, for lead-free piezoelectric ceramic, 0.74(Bi0.5Na0.5TiO3)-0.26(SrTiO3) (BNT-ST26) and niobium-substituted (Nb-BNT–ST26) ceramics were synthesized by solid-state reactions. The evolution of niobium substitution to the perovskite phase structure of BNT-ST26 ceramics was confirmed by X-ray diffraction (XRD) analysis and Raman spectra. Electromechanical properties of Nb-BNT-ST26 ceramics initially increased with the addition of niobium up to 0.5% and decreased with a further increase in Nb content. Temperature-dependent dielectric curves showed that the depolarization temperature (Td) decreased below room temperature because of Nb substitution. The composition with 0.5% Nb yielded a maximum bipolar strain (Smax) of 0.265% and normalized strain of d33* ~ 576 pm/V under an electric field of 4.6 kV/mm at room temperature. At this critical concentration of 0.5% Nb, maximum saturation polarization of 26 μC/cm2 was achieved. The dielectric constant with temperature peaks became more diffused and the depolarization temperature decreased with the increasing Nb content. The study concludes that Nb-doped BNT-ST26 is an excellent material for high-temperature, stable, frequency-dependent, lead-free piezoelectric devices.
The ISM Method to Analyze the Relationship between Blockchain Adoption Criteria in University: An Indonesian Case
Authors: Yu Vincent F. , Bahauddin Achmad , Ferdinant Putro F. , Fatmawati Agustina , Lin Shih-Wei
Published: January 2023

Referring to the widespread problem of diploma forgery in Indonesian educational institutions as the impetus for UNTIRTA’s latest vision as an “Integrated, Smart, and Green University,” UNTIRTA intends to use blockchain technology to prevent diploma forgery and overcome issues related to existing platforms at UNTIRTA, such as frequent connection interruptions when accessed by a large number of users simultaneously. Before using blockchain technology, UNTIRTA must evaluate several readiness issues. This study presented the interpretative structural modeling (ISM) method to assess the primary preparedness elements for adopting blockchain technology in universities and sought to provide pertinent strategy ideas for UNTIRTA’s blockchain technology application. The results reveal sixteen major parameters that influence the adoption readiness of blockchain technology at UNTIRTA. The primary variables impacting the adoption and deployment of blockchain technology at UNTIRTA are management and employee support and a grasp of the technology. To realize UNTIRTA’s mission as an “Integrated, Smart, and Green University”, the proposed method entails determining an initial agreement in which all stakeholders have a shared understanding and commitment to Blockchain technology implementation at UNTIRTA. The objective of the tactical proposal is to establish each unit’s mission in the blockchain implementation program. The objective of the technical proposal is to construct a planning document that will serve as a coordination tool between the chairman and members, as well as all parties interested in the adoption of Blockchain technology at UNTIRTA.
Multiaxial Strength Criterion Model of Concrete Based on Random Forest
Authors: Chen Xingqiao , Zheng Dongjian , Liu Yongtao , Wu Xin , Jiang Haifeng , Qiu Jianchun
Published: January 2023

The concrete strength criterion is the basis of strength analysis and evaluation under a complex stress state. In this paper, a large number of multiaxial strength tests were carried out, and many mathematical expressions of strength criteria were proposed based on the geometric characteristics and the assumption of a convex function. However, the rationality of the assumption of a convex function limits the use of these strength criteria. In particular, misjudgment will occur near the failure curve surface. Therefore, this paper does not assume the shape function of the criterion in advance. By collecting experimental data and using a machine learning method, it proposes a method of hidden function of failure curve surface. Based on 777 groups of experimental data, the random forest (RF), the back propagation neural network (BP) and the radial basis neural network (RBF) models were used to analyze and verify the feasibility and effectiveness of the method. Subsequently, the results were compared with the Ottosen strength criterion, the Guo Wang strength criterion and the Drucker–Prager (DP) strength criterion. The results show that the consistency between the strength criterion model established by the machine learning algorithm (especially random forest) and the experimental data is higher than the convex function multiaxis strength criterion of the preset failure surface shape. Moreover, the physical significance is clearer, the deficiency of the convex function failure surface hypothesis is avoided and the established multiaxial strength criterion of concrete is more universal.
Challenges and Opportunities for Education Systems with the Current Movement toward Digitalization at the Time of COVID-19
Authors: Sadjadi Ebrahim Navid
Published: January 2023

The spread of coronavirus has caused the shutdown of businesses and classroom participation to enable social distancing. It has led to the promotion of digitalization in societies and online activities. This manuscript presents an overview of the measures education systems could take to present appropriate courses in accordance with the present movement toward digitalization, and other requirements of societies in the (post) crisis period.
Efficient Monte Carlo Methods for Multidimensional Modeling of Slot Machines Jackpot
Authors: Georgiev Slavi , Todorov Venelin
Published: January 2023

Nowadays, entertainment is one of the biggest industries, which continues to expand. In this study, the problem of estimating the consolation prize as a fraction of the jackpot is dealt with, which is an important issue for each casino and gambling club. Solving the problem leads to the computation of multidimensional integrals. For that purpose, modifications of the most powerful stochastic quasi-Monte Carlo approaches are employed, in particular lattice and digital sequences, Halton and Sobol sequences, and Latin hypercube sampling. They show significant improvements to the classical Monte Carlo methods. After accurate computation of the arisen integrals, it is shown how to calculate the expectation of the real consolation prize, taking into account the distribution of time, when different numbers of players are betting. Moreover, a solution to the problem with higher dimensions is also proposed. All the suggestions are verified by computational experiments with real data. Besides gambling, the results obtained in this study have various applications in numerous areas, including finance, ecology and many others.
The Biological Activity of Fragmented Computer-Aided Design/Manufacturing Dental Materials before and after Exposure to Acidic Environment
Authors: Ille Codruța Eliza , Moacă Elena-Alina , Suciu Maria , Barbu-Tudoran Lucian , Negruțiu Meda-Lavinia , Jivănescu Anca
Published: January 2023

Three ceramic and composite computer-aided design/computer-aided manufacturing (CAD/CAM) materials from different manufacturers (Cerasmart (CS)—nanoceramic resin; Straumann Nice (SN)—glass ceramic and Tetric CAD (TC)—composite resin) were tested to investigate the biocompatibility and sustainability on human fibroblasts and keratinocytes cells. Each type of CAD/CAM blocks restorative materials with fine and rough surfaces was exposed to an acidic environment for one month. After that, various powders were obtained by milling. In parallel, powders were also prepared from each restorative material, which were not exposed to the acidic environment. The cytotoxic effects were investigated by means of MTT and LDH assays, as well as nitric oxide production on two human normal cell lines, namely, fibroblasts (BJ) and keratinocytes (HaCaT). In addition, the degree of adhesion of fibroblast cells to each CAD/CAM material was evaluated by scanning electron microscopy (SEM). The results showed that the two samples that were exposed to an acidic environment (CS and SN) induced a reduction of mitochondrial activity and plasma membrane damage as regards the fibroblast cells. A similar effect was observed in TC_fine-exposed material, which seemed to induce necrosis at the tested concentration of 1 mg/mL. No oxidative stress was observed in fibroblasts and keratinocytes treated with the CAD/CAM materials. Regarding the adhesion degree, it was found that the fibroblasts adhere to all the occlusal veneers tested, with the mention that the CS and SN materials have a weaker adhesion with fewer cytoplasmic extensions than TC material. With all of this considered, the CAD/CAM restorative materials tested are biocompatible and represent support for the attachment and dispersion of cells.
Predictors of Oral Health Behaviors among Dental Students
Authors: Armencia Adina Oana , Feier Ramona , Dănilă Vlad , Budală Dana Gabriela , Balcoș Carina , Baciu Dana , Prelipceanu Marius , Vicoveanu Dragoș Ionuț
Published: January 2023

Background and Objectives: College life is a time when students take more responsibility for health-related behaviors. Aim: To determine the oral health behaviors of dental students, to motivate their transformation into cyanogenic behaviors by applying the planned behavior model, and to determine the degree to which students can modify behavior for oral health. Material and Methods: The results of the initial and final assessment (4 months apart) of the bacterial plaque present by means of the Quigley Hein and API indexes were collected from the student files. The Health-Promoting Lifestyle Profile II -HPLP II and Generalized Self-Efficacy Scale (GSE) questionnaires were used to determine the variables with predictor values that influence the cognitive-perceptual factors. Results: For the “health responsibility” domain, the average total value was 2.53 ± 0.9 (SD). For the “interpersonal relationships” domain, the average value was 2.82 ± 0.79. In the case of the “nutrition” domain, the desire to change the behavior of the participants was moderate (2.53 ± 1.19). “Physical activity” represents an important field in the everyday life of young adults. The results of the study indicated a moderate desire for change (2.52 ± 0.97). In the case of “spiritual growth”, in which self-esteem, the way the individual perceives the environment and the adaptation to it were evaluated, a great desire for change was observed (2.74 ± 0.82). Scale GSE questionnaire showed an α coefficient of 28.52 ± 0.82, a value that indicated a moderate to a high level of efficacy and self-confidence. Conclusions: The results of the study showed that students have a moderate tendency to change in all areas, except for interpersonal relationships, where the desire to change something is increased. The participants have a moderate to a high level of self-efficacy and self-confidence.
NucEnvDB: A Database of Nuclear Envelope Proteins and Their Interactions
Authors: Baltoumas Fotis , Sofras Dimitrios , Apostolakou Avgi , Litou Zoi , Iconomidou Vassiliki
Published: January 2023

The nuclear envelope (NE) is a double-membrane system surrounding the nucleus of eukaryotic cells. A large number of proteins are localized in the NE, performing a wide variety of functions, from the bidirectional exchange of molecules between the cytoplasm and the nucleus to chromatin tethering, genome organization, regulation of signaling cascades, and many others. Despite its importance, several aspects of the NE, including its protein–protein interactions, remain understudied. In this work, we present NucEnvDB, a publicly available database of NE proteins and their interactions. Each database entry contains useful annotation including a description of its position in the NE, its interactions with other proteins, and cross-references to major biological repositories. In addition, the database provides users with a number of visualization and analysis tools, including the ability to construct and visualize protein–protein interaction networks and perform functional enrichment analysis for clusters of NE proteins and their interaction partners. The capabilities of NucEnvDB and its analysis tools are showcased by two informative case studies, exploring protein–protein interactions in Hutchinson–Gilford progeria and during SARS-CoV-2 infection at the level of the nuclear envelope.
The Infarct-Reducing Effect of the δ2 Opioid Receptor Agonist Deltorphin II: The Molecular Mechanism
Authors: Popov Sergey V. , Mukhomedzyanov Alexandr V. , Maslov Leonid N. , Naryzhnaya Natalia V. , Kurbatov Boris K. , Prasad N. Rajendra , Singh Nirmal , Fu Feng , Azev Viacheslav N.
Published: January 2023

The search for novel drugs for the treatment of acute myocardial infarction and reperfusion injury of the heart is an urgent aim of modern pharmacology. Opioid peptides could be such potential drugs in this area. However, the molecular mechanism of the infarct-limiting effect of opioids in reperfusion remains unexplored. The objective of this research was to study the signaling mechanisms of the cardioprotective effect of deltorphin II in reperfusion. Rats were subjected to coronary artery occlusion (45 min) and reperfusion (2 h). The ratio of infarct size/area at risk was determined. This study indicated that the cardioprotective effect of deltorphin II in reperfusion is mediated via the activation of peripheral δ2 opioid receptor (OR), which is most likely localized in cardiomyocytes. We studied the role of guanylyl cyclase, protein kinase Cδ (PKCδ), phosphatidylinositol-3-kinase (PI3-kinase), extracellular signal-regulated kinase-1/2 (ERK1/2-kinase), ATP-sensitive K+-channels (KATP channels), mitochondrial permeability transition pore (MPTP), NO synthase (NOS), protein kinase A (PKA), Janus 2 kinase, AMP-activated protein kinase (AMPK), the large conductance calcium-activated potassium channel (BKCa-channel), reactive oxygen species (ROS) in the cardioprotective effect of deltorphin II. The infarct-reducing effect of deltorphin II appeared to be mediated via the activation of PKCδ, PI3-kinase, ERK1/2-kinase, sarcolemmal KATP channel opening, and MPTP closing.
Effect of Local Fluid Disturbance Induced by Weld Reinforcement Height on the Corrosion of a Low Alloy Steel Weld
Authors: Zheng Kexin , Hu Hongxiang , Wang Zhengbin , Zheng Yugui , Zhao Liang , Shang Xianhe
Published: January 2023

Weld corrosion exists widely in the petrochemical industry and attracts great attention. Most research proves that weld corrosion originates from the material factors introduced during the welding process. However, it is noted that local fluid turbulence due to the weld reinforcement height (WRH) plays an important role in the non-uniform corrosion of welds in flowing media. Accordingly, the individual effect of the local flow on the weld corrosion of low alloy steel was analyzed by experiments and simulation in this study. Electrochemical measurements and morphology observation were conducted, combined with flow field analyses. The results showed that local fluid turbulence due to WRH affected the non-uniform corrosion of low alloy steel welds. The upstream surface and the backflow surface had the highest and lowest corrosion rates, respectively. Interestingly, the high flow velocity surface region did not have a high-corrosion rate. This is due to the combined effects of mass transfer, charge transfer, and wall shear stress. The pitting corrosion was also discussed in view of the aspects above.
On Ausferrite Produced in Thin Sections: Stability Assessment through Round and Flat Tensile Specimen Testing
Authors: Angella Giuliano , Donnini Riccardo , Ripamonti Dario , Bonollo Franco , Cygan Bogdan , Gorny Marcin
Published: January 2023

Ductile irons were produced into different casting wall sections, that is, 25 mm, 5 mm and 3 mm. The alloys were then austenitized with the same conditions at 875 °C for 2 h and austempered for three different combinations of temperatures and times: 250 °C for 6 h, 310 °C for 3 h and 380 °C for 1 h. The aim of the investigation was to study the ausferrite stability of austempered ductile irons with three different nominal contents of nickel produced in thin sections through tensile testing. So, strain hardening analysis of tensile flow curves was carried out since it has been found to be a reliable support to ductility analysis in assessing the optimal austempering conditions. Because of different wall sections, round and flat tensile specimens with geometries complying with ASTM E8/E8M-11 were tested. Austempered ductile irons from 5 and 3 mm wall sections were tested through flat geometry specimens only, while 25 mm wall sections were tested through both round and flat geometries. Though the ausferrite was affected by Ni content and the graphite morphology was improved with reduced thin sections, the ausferrite stability and the tensile mechanical behavior were insensitive to Ni content and section thickness below 25 mm. Furthermore, it resulted that the tensile plastic behavior was sensitive to the specimen geometry in a consistent way, increasing the instability of ausferrite and indicating that a proper analysis and comparison of tensile properties of austempered ductile irons must take into account the tensile specimen geometry.
Data Augmentation of Micrographs and Prediction of Impact Toughness for Cast Austenitic Steel by Machine Learning
Authors: Xu Gang , Zhang Xiaotong , Xu Jinwu
Published: January 2023

The Material Genome Initiative has been driven by high-throughput calculations, experiments, characterizations, and machine learning, which has accelerated the efficiency of the discovery of novel materials. However, the precise quantification of the material microstructure features and the construction of microstructure–property models are still challenging in optimizing the performance of materials. In this study, we proposed a new model based on machine learning to enhance the power of the data augmentation of the micrographs and construct a microstructure–property linkage for cast austenitic steels. The developed model consists of two modules: the data augmentation module and microstructure–property linkage module. The data augmentation module used a multi-layer convolution neural network architecture with diverse size filter to extract the microstructure features from irregular micrographs and generate new augmented microstructure images. The microstructure–property linkage module used a modified VGG model to establish the relationship between the microstructure and material property. Taking cast austenitic stainless steels after solution treating in different temperatures as an example, the results showed that the prediction accuracy of the developed machine learning model had been improved. The coefficient R2 of the model was 0.965, and the medians were only ±2 J different with the measured impact toughness.
Corrosion Induced Morphology Evolution in Stressed Solids
Authors: Dong Zhelin , Zhang Weixu , Li Xiaozhen , Han Mingda , Long Bin , Jiang Peng
Published: January 2023

Corrosion morphology is a key factor that influences the reliability and service life of a structure. As most structures service under stress corrosion, there is a great need to understand the effect of stress on the formation conditions of different morphologies. This paper introduces a numerical method to simulate the evolution of surface morphologies. The results indicate that a corroded surface will become rougher and sharper with an increase in stress, and as a consequence, the corrosion morphology will transfer from a flatter surface to a pit and then a crevice. The critical stress values for different morphologies (crevice, pit, and a flatter surface) were captured. Among the three morphologies, the flatter surface and pit maintain a fixed shape, also known as stable morphology. As stress exceeds a critical value, crevices are generated, and the morphology evolution becomes unstable. On the basis of the simulation results, the influence of morphology on the service life of the structure was evaluated. The corrosion velocity of a rough surface exceeds that of a flat surface, and this reduces the service life of the structure more significantly. With a rise in applied stress, the acceleration of corrosion presents a quadratically increasing relationship with applied stress.
Sociodemographic, Anthropometric, Body Composition, Nutritional, and Biochemical Factors Influenced by Age in a Postmenopausal Population: A Cross-Sectional Study
Authors: Vázquez-Lorente Héctor , Herrera-Quintana Lourdes , Molina-López Jorge , López-González Beatriz , Planells Elena
Published: January 2023

Postmenopausal aging has become relevant for understanding health during the transition life stages—the aging process being involved in several disturbances of the human condition. The present study aimed to investigate the relationship between postmenopausal aging and sociodemographic, anthropometric, body composition, nutritional, and biochemical (i.e., protein and lipid profiles, phosphorous-calcium metabolism, and antioxidant status) factors in postmenopausal women. This cross-sectional study enrolled 78 healthy postmenopausal women (44–76 years). The anthropometrical data showed no differences by age. Biochemical parameters, especially those involved in the protein and phosphorous-calcium metabolism, were influenced by age in our cohort of postmenopausal women. In contrast, no associations were found when considering lipid and antioxidant parameters. Height, fiber intake, blood glucose, protein profile and phosphorous-calcium metabolism markers seem to be the most affected nutritional-related factors by age in our cohort of healthy postmenopausal women. Primary prevention strategies focused on parameters at risk of disruption with postmenopausal aging are necessary to ensure the quality of life in older ages.
20-Hydroxyecdysone and Receptor Interplay in the Regulation of Hemolymph Glucose Level in Honeybee (Apis mellifera) Larvae
Authors: Yu Jing , Wang Hongfang , Chen Wenfeng , Song Hongyu , Wang Ying , Liu Zhenguo , Xu Baohua
Published: January 2023

The hormone 20-hydroxyecdysone (20E) and the ecdysone receptors (ECR and USP) play critical roles in the growth and metabolism of insects, including honeybees. In this study, we investigated the effect of 20E on the growth and development of honeybee larvae by rearing them in vitro and found reduced food consumption and small-sized pupae with increasing levels of 20E. A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based analysis of widely targeted metabolomics was used to examine the changes in the metabolites after an exogenous 20E application to honeybee larvae and the underlying mechanisms. A total of 374 different metabolites were detected between the control group and the 20E treatment group, covering 12 subclasses. The most significant changes occurred in 7-day-old larvae, where some monosaccharides, such as D-Glucose and UDP-galactose, were significantly upregulated. In addition, some metabolic pathways, such as glycolysis/gluconeogenesis and galactose metabolism, were affected by the 20E treatment, suggesting that the 20E treatment disrupts the metabolic homeostasis of honeybee larvae hemolymph and that the response of honeybee larvae to the 20E treatment is dynamic and contains many complex pathways. Many genes involved in carbohydrate metabolism, including genes of the glycolysis and glycogen synthesis pathways, were downregulated during molting and pupation after the 20E treatment. In contrast, the expression levels of the genes related to gluconeogenesis and glycogenolysis were significantly increased, which directly or indirectly upregulated glucose levels in the hemolymph, whereas RNA interference with the 20E receptor EcR-USP had an opposite effect to that of the 20E treatment. Taken together, 20E plays a critical role in the changes in carbohydrate metabolism during metamorphosis.
A Printed Reconfigurable Monopole Antenna Based on a Novel Metamaterial Structures for 5G Applications
Authors: Al-Hadeethi Saba T. , Elwi Taha A. , Ibrahim Abdullahi A.
Published: January 2023

A novel antenna structure is constructed from cascading multi-stage metamaterial (MTM) unit cells-based printed monopole antenna for 5G mobile communication networks. The proposed antenna is constructed from a printed conductive trace that fetches four MTM unit cells through four T-Resonators (TR) structures. Such a combination is introduced to enhance the antenna gain-bandwidth products at sub-6GHz bands after exiting the antenna with a coplanar waveguide (CPW) feed. The antenna circuitry is fabricated by etching a copper layer that is mounted on Taconic RF-43 substrate. Therefore, the proposed antenna occupies an effective area of 51 × 24 mm2. The proposed antenna provides an acceptable matching impedance with S11 ≤ −10 dB at 3.7 GHz, 4.6 GHz, 5.2 GHz, and 5.9 GHz. The antenna radiation patterns are evaluated at the frequency bands of interest with a gain average of 9.1–11.6 dBi. Later, to control the antenna performance, four optical switches based on LDR resistors are applied to control the antenna gain at 5.85 GHz, which is found to vary from 2 dBi to 11.6 dBi after varying the value of the LDR resistance from 700 Ω to 0 Ω, in descending manner. It is found that the proposed antenna provides an acceptable bit error rate (BER) with varying the antenna gain in a very acceptable manner in comparison to the ideal performance. Finally, the proposed antenna is fabricated to be tested experimentally in in free space and in close to the human body for portable applications.
A Deep-Hole Microdrilling Study of Pure Magnesium for Biomedical Applications
Authors: Pizzi Margherita , De Gaetano Francesco , Ferroni Marco , Boschetti Federica , Annoni Massimiliano
Published: January 2023

The mechanisms of deep-hole microdrilling of pure Mg material were experimentally studied in order to find a suitable setup for a novel intraocular drug delivery device prototyping. Microdrilling tests were performed with 0.20 mm and 0.35 mm microdrills, using a full factorial design in which cutting speed vc and feed fz were varied over two levels. In a preliminary phase, the chip shape was evaluated for low feeds per tooth down to 1 μm, to verify that the chosen parameters were appropriate for machining. Subsequently, microdrilling experiments were carried out, in which diameter, burr height and surface roughness of the drilled holes were examined. The results showed that the burr height is not uniform along the circumference of the holes. In particular, the maximum burr height increases with higher cutting speed, due to the thermal effect that plasticizes Mg. Hole entrance diameters are larger than the nominal tool diameters due to tool runout, and their values are higher for high vc and fz. In addition, the roughness of the inner surface of the holes increases as fz increases.
Design and Implementation of a SiC-Based Multifunctional Back-to-Back Three-Phase Inverter for Advanced Microgrid Operation
Authors: Ma Chao-Tsung , Zheng Zhi-Yuan
Published: January 2023

Because of the worldwide trend of microgrid (MG) and renewable energy (RE)-based distributed power generation (DG), advanced power flow control schemes with wide bandgap (WBG) semiconductor technologies to ensure high-level performance of grid-connected MGs is one of the crucial research topics. In grid-connected MGs, a static switch (SS) is commonly used at the point of common coupling (PCC) of two systems. In this paper, the role of SS is replaced by a SiC-based three-phase back-to-back (BTB) inverter system for seamless switching between grid-connected and standalone modes through advanced power flow control schemes. According to scenarios of different grid/load conditions and available DG capacities in an MG, various advanced control functions can be developed for both MG operating modes: bidirectional control of active and reactive power flows, seamless switching between operating modes, improvement of grid power quality (PQ), and voltage stabilization. In this paper, mathematical models of the BTB inverter in a synchronous reference frame (SRF) is first derived, and the required controllers are then designed. For functional testing, two typical cases are simulated and analyzed in a MATLAB/Simulink environment and then verified through 1kVA small-scale hardware implementation with Texas Instruments (TI) digital signal processor (DSP) TMS320LF2812 as the control core. Results show satisfactory performances of power flow control and PQ improvement of MG.
Epidemiological Analysis on the Occurrence of Salmonella enterica Subspecies enterica Serovar Dublin in the German Federal State Schleswig-Holstein Using Whole-Genome Sequencing
Authors: García-Soto Silvia , Linde Jörg , Methner Ulrich
Published: January 2023

The cattle-adapted serovar Salmonella Dublin (S. Dublin) causes enteritis and systemic diseases in animals. In the German federal state Schleswig-Holstein, S. Dublin is the most important serovar in cattle indicating an endemic character of the infection. To gain information on dissemination and routes of infection, whole-genome sequencing (WGS) was used to explore the genetic traits of 78 S. Dublin strains collected over a period of six years. The phylogeny was analysed using core-genome single nucleotide polymorphisms (cgSNPs). Genomic clusters at 100, 15 and 1 cgSNPs were selected for molecular analysis. Important specific virulence determinants were detected in all strains but multidrug resistance in S. Dublin organisms was not found. Using 15 cgSNPs epidemiological links between herds were identified, clusters at 1 cgSNPs provided clear evidence on both persistence of S. Dublin at single farms in consecutive years and transmission of the organisms between herds in different distances. A possible risk factor for the repeated occurrence of S. Dublin in certain districts of Schleswig-Holstein might be the spreading of manure on pastures and grassland. Effective control of S. Dublin requires farm-specific analysis of the management supplemented by WGS of outbreak causing S. Dublin strains to clearly identify routes of infection.
The Antifungal Properties of Tamarix aphylla Extract against Some Plant Pathogenic Fungi
Authors: Al-Otibi Fatimah , Moria Ghaida A. , Alharbi Raedah I. , Yassin Mohamed T. , Al-Askar Abdulaziz A.
Published: January 2023

Tamarix aphylla is a Saudi herb, which possesses antimicrobial properties and potentially introduces a solution to the subsequent dilemma caused by agrochemicals and antifungal misuse. The current study aimed to assess the fungicidal properties of water and ethanolic extracts of T. aphylla leaves against Macrophomina phaseolina, Curvularia spicifera, and Fusarium spp. The chemical composition of T. aphylla was evaluated by gas chromatography/mass spectrometry technique (GC–MS) and Fourier-transform infrared spectroscopy (FTIR). The antifungal assay assessed the fungal growth inhibition using the poisoned food technique. Scanning and transmission electron microscopy (SEM and TEM) were used to evaluate the structural changes induced in the fungal species post-treatment by T. aphylla. FTIR and GC–MS analysis revealed that T. aphylla extracts were rich in aromatic and volatile compounds, such as Benzeneselenol, Gibberellic acid, and Triaziquone, which proved multiple antifungal properties. The results showed significant inhibition in the growth of all species (p < 0.05) except for F. moniliforme, where the water extract induced the highest mycelial growth inhibition at the dose of 30%. The highest inhibition was for M. phaseolina treated with the water extract (36.25 ± 1.06 mm, p < 0.001) and C. spicifera, treated with the ethanolic extract (27.25 ± 1.77 mm, p < 0.05), as compared to the untreated control and the positive control of Ridomol. SEM and TEM revealed some ultrastructural changes within the fungal growth of treated M. phaseolina, which included the thickening and mild rupture of mycelia. Those findings suggested the robust antifungal properties of T. aphylla against some filamentous fungi. The phenolic composition illustrated the potential fungicidal properties of T. aphylla. Additional studies are required to focus on more antimicrobial properties of T. aphylla against other species, particularly those that might benefit the medical field.
Stable Carbon and Oxygen Isotopic Features of Banded Travertines from the Xiagei Fissure Ridge System (Shangri-La, China)
Authors: You Yaxian , Wen Huaguo , Luo Lianchao , Lu Zhipeng , Li Liang
Published: January 2023

Banded travertines are important parts of fissure ridge systems, but studies on geochemical characterization of banded travertines are limited. This study investigated the lithofacies and stable carbon and oxygen isotopic features of banded travertines from Xiagei (southwestern China) to examine their formation mechanisms. Petrographic analyses of the banded travertines revealed two lithotypes: thick-laminated palisade crystalline crust and thin-laminated composite crystalline crust. δ13C and δ18O of the Xiagei banded travertines range from 2.82‰ to 4.50‰ V-PDB, and from −25.86‰ to −20.90‰ V-PDB. Parent CO2 evaluation shows that the Xiagei banded travertines mainly received CO2 from the decarbonation of marine carbonates, but the contributions of magmatic CO2 and the dissolution of marine carbonates are also unneglectable. Significantly, the magmatic-derived CO2 might indicate that the delamination of the lithosphere along with the asthenosphere upwelling could be taking place in the eastern Tibetan plateau. Paleotemperature calculation shows that the Xiagei travertines were precipitated from moderate- to high-temperature hot springs (44.3 to 86.8 °C). Interestingly, the thick-laminated palisade crystalline crust and thin-laminated composite crystalline crust display calculated paleotemperature between 66.6 and 86.8 °C and between 56.6 and 77.7 °C, respectively, reflecting the great role of water temperature in controlling the lithofacies of banded travertines. A comparison between the banded travertines at Xiagei and other areas also shows temperature is a non-negligible factor controlling banded travertine precipitation. However, this does not mean that water temperature is the decisive controlling factor and more studies on banded travertines are still indispensable to disclose the potential factors controlling the factors/processes affecting banded travertine lithofacies. This study provides a good example for understanding the relationship between lithofacies and stable isotopic geochemical characteristics of travertine deposits.
Strategies for Targeting in Undercover Terrains: Modeling Multi-Source Data in Apuí Region, SW Amazon Craton, Brazil
Authors: Queiroz Lila , Silva Adalene , e Sousa Frederico , Pitarello Michele , Moura Márcia
Published: January 2023

Exploring covered terrains is a challenge that requires the integration of multiple sources of knowledge, particularly in the initial stages of mineral exploration. The Apuí region, located in the Southwestern Amazon Craton, has a small and constant gold production, despite the deep cover and limited geological knowledge. The gold is mainly hosted in quartz veins and breccias that cut Paleoproterozoic volcano-sedimentary sequences. The occurrences have similar characteristics to magmatic–hydrothermal deposits, such as a lack of regional metamorphism and intense hydrothermalization. We undertook a multi-source prospective investigation on different scales using 2D and 3D techniques to translate the footprints of the mineral system into mappable criteria. Gold prospectivity maps for the Juma District and Guida Target were produced by integrating geological, geochemical, and geophysical datasets in knowledge-driven fuzzy systems. Regional airborne magnetization vector inversion (MVI) models were utilized. The correlation between the drill cores and the magnetic susceptibility models highlighted a potential surface for gold mineralization associated with the boundary between a granitic intrusion and volcano-sedimentary rocks. The prospectivity maps reduced the search area, and the regional susceptibility models allowed for the reconnaissance of structures and bodies that may be related to gold mineralization at depth. The results present new strategies for increasing discovery performance in the Southern Amazon Craton under cover.
New N4-Donor Ligands as Supramolecular Guests for DNA and RNA: Synthesis, Structural Characterization, In Silico, Spectrophotometric and Antimicrobial Studies
Authors: Ewert Ernest , Pospieszna-Markiewicz Izabela , Szymańska Martyna , Kurkiewicz Adrianna , Belter Agnieszka , Kubicki Maciej , Patroniak Violetta , Fik-Jaskółka Marta A. , Roviello Giovanni N.
Published: January 2023

The present work reports the synthesis of new N4-donor compounds carrying p-xylyl spacers in their structure. Different Schiff base aliphatic N-donors were obtained synthetically and subsequently evaluated for their ability to interact with two models of nucleic acids: calf-thymus DNA (CT-DNA) and the RNA from yeast Saccharomyces cerevisiae (herein simply indicated as RNA). In more detail, by condensing p-xylylenediamine and a series of aldehydes, we obtained the following Schiff base ligands: 2-thiazolecarboxaldehyde (L1), pyridine-2-carboxaldehyde (L2), 5-methylisoxazole-3-carboxaldehyde (L3), 1-methyl-2-imidazolecarboxaldehyde (L4), and quinoline-2-carboxaldehyde (L5). The structural characterisation of the ligands L1-L5 (X-ray, 1H NMR, 13C NMR, elemental analysis) and of the coordination polymers {[CuL1]PF6}n (herein referred to as Polymer1) and {[AgL1]BF4}n, (herein referred to as Polymer2, X-ray, 1H NMR, ESI-MS) is herein described in detail. The single crystal X-ray structures of complexes Polymer1 and Polymer2 were also investigated, leading to the description of one-dimensional coordination polymers. The spectroscopic and in silico evaluation of the most promising compounds as DNA and RNA binders, as well as the study of the influence of the 1D supramolecular polymers Polymer1 and Polymer2 on the proliferation of Escherichia coli bacteria, were performed in view of their nucleic acid-modulating and antimicrobial applications. Spectroscopic measurements (UV–Vis) combined with molecular docking calculations suggest that the thiazolecarboxaldehyde derivative L1 is able to bind CT-DNA with a mechanism different from intercalation involving the thiazole ring in the molecular recognition and shows a binding affinity with DNA higher than RNA. Finally, Polymer2 was shown to slow down the proliferation of bacteria much more effectively than the free Ag(I) salt.
Impact of Thermal Processing on the Selected Biological Activities of Ginger Rhizome—A Review
Authors: Zagórska Justyna , Czernicka-Boś Lidia , Kukula-Koch Wirginia , Iłowiecka Katarzyna , Koch Wojciech
Published: January 2023

Ginger (Zingiber officinale Rosc.) is a spice, medicinal and cosmetic plant that has been known for centuries. It can be used in dried, fresh, marinated or candied form, and is also an essential ingredient in well-known curry blends. Ginger rhizomes are often freeze-dried as the first step in the preparation of the raw material. Many studies have proved that the composition and biological activity of ginger changes due to thermal processing. Therefore, the aim of the review was to summarize the scientific results on the impact of traditional and unconventional methods of the heat treatment of ginger rhizomes and their influence on the antioxidant and other selected biological activities of the plant. The review of the available scientific data is inconclusive, and it is hard to state unequivocally whether the thermal treatment of the raw material increases or decreases biological activity. Based on the presented literature review, it can be concluded that traditional cooking and microwave processing in general decrease the antioxidant activity of the ginger rhizome, whereas frying, autoclaving, blanching or traditional drying in the sun mostly lead to a significant increase in ginger activity. Interesting data were presented in the works describing the freeze-drying process during which the antioxidant potential of ginger increased.
Neuroprotective Effect of Quercetin and Memantine against AlCl3-Induced Neurotoxicity in Albino Wistar Rats
Authors: Jadhav Ratnakar , Kulkarni Yogesh A.
Published: January 2023

Recent evidences indicate that there is a substantial increase in worldwide cases of dementia. Alzheimer’s disease is the leading cause of dementia and may contribute to 60–70% of cases. Quercetin is a unique bioflavonoid that has numerous therapeutic benefits such as anti-allergy, anti-ulcer, anti-inflammatory, anti-hypertensive, anti-cancer, immuno-modulatory, anti-infective, antioxidant, acetylcholinesterase inhibitory activity, neuroprotective effects, etc. In the present study, we evaluated the neuroprotective effect of orally administered quercetin with memantine in albino Wistar rats after inducing neurotoxicity through AlCl3 (100 mg/kg, p.o.). Chronic administration of AlCl3 resulted in poor retention of memory and significant oxidative damage. Various behavioral parameters, such as locomotor activity, Morris water maze, elevated plus maze, and passive avoidance test, were assessed on days 21 and 42 of the study. The animals were euthanatized following the completion of the last behavioral assessment. Various oxidative stress parameters were assessed to know the extent of oxidative damage to brain tissue. Quercetin with memantine has shown significant improvement in behavioral studies, inhibition of AChE activity, and reduction in oxidative stress parameters. Histopathological studies assessed for cortex and hippocampus using hematoxylin and eosin (H&E), and Congo red stain demonstrated a reduction in amyloid-β plaque formation after treatment of quercetin with memantine. Immunohistochemistry showed that quercetin with memantine treatment also improved the expression of brain-derived neurotrophic factor (BDNF) and inhibited amyloid-β plaque formation. The present study results demonstrated protective effects of treatment of quercetin with memantine in the neurotoxicity linked to aluminum chloride in albino Wistar rats.