bluuebunny/crossref_metadata_2025 huggingface dataset:
Is There an Advantage of Ultrathin-Strut Drug-Eluting Stents over Second- and Third-Generation Drug-Eluting Stents?
Authors: Gherasie Flavius-Alexandru , Valentin Chioncel , Busnatu Stefan-Sebastian
Published: April 2023

In patients undergoing percutaneous coronary intervention, the second-generation drug-eluting stents (DES) are considered the gold standard of care for revascularization. By reducing neointimal hyperplasia, drug-eluting coronary stents decrease the need for repeat revascularizations compared with conventional coronary stents without an antiproliferative drug coating. It is important to note that early-generation DESs were associated with an increased risk of very late stent thrombosis, most likely due to delayed endothelialization or a delayed hypersensitivity reaction to the polymer. Studies have shown a lower risk of very late stent thrombosis with developing second-generation DESs with biocompatible and biodegradable polymers or without polymers altogether. In addition, research has indicated that thinner struts are associated with a reduced risk of intrastent restenosis and angiographic and clinical results. A DES with ultrathin struts (strut thickness of 70 µm) is more flexible, facilitates better tracking, and is more crossable than a conventional second-generation DES. The question is whether ultrathin eluting drug stents suit all kinds of lesions. Several authors have reported that improved coverage with less thrombus protrusion reduced the risk of distal embolization in patients with ST-elevation myocardial infarction (STEMI). Others have described that an ultrathin stent might recoil due to low radial strength. This could lead to residual stenosis and repeated revascularization of the artery. In CTO patients, the ultrathin stent failed to prove non-inferiority regarding in-segment late lumen loss and showed statistically higher rates of restenosis. Ultrathin-strut DESs with biodegradable polymers have limitations when treating calcified (or ostial) lesions and CTOs. However, they also possess certain advantages regarding deliverability (tight stenosis, tortuous lesions, high angulation, etc.), ease of use in bifurcation lesions, better endothelialization and vascular healing, and reducing stent thrombosis risk. In light of this, ultrathin-strut stents present a promising alternative to existing DESs of the second and third generation. The aims of the study are to compare ultrathin eluting stents with second- and third-generation conventional stents regarding procedural performance and outcomes based on different lesion types and specific populations.
T Lymphocyte Subset Counts and Interferon-Gamma Production in Adults and Children with COVID-19: A Narrative Review
Authors: De Rose Domenico Umberto , Pace Pier Giorgio , Ceccherini-Silberstein Francesca , Dotta Andrea , Andreoni Massimo , Sarmati Loredana , Iannetta Marco
Published: April 2023

Adults and children exhibit a broad range of clinical outcomes from SARS-CoV-2 infection, with minimal to mild symptoms, especially in the pediatric age. However, some children present with a severe hyperinflammatory post-infectious complication named multisystem inflammatory syndrome in children (MIS-C), mainly affecting previously healthy subjects. Understanding these differences is still an ongoing challenge, that can lead to new therapeutic strategies and avoid unfavorable outcomes. In this review, we discuss the different roles of T lymphocyte subsets and interferon-γ (IFN-γ) in the immune responses of adults and children. Lymphopenia can influence these responses and represent a good predictor for the outcome, as reported by most authors. The increased IFN-γ response exhibited by children could be the starting point for the activation of a broad response that leads to MIS-C, with a significantly higher risk than in adults, although a single IFN signature has not been identified. Multicenter studies with large cohorts in both age groups are still needed to study SARS-CoV-2 pathogenesis with new tools and to understand how is possible to better modulate immune responses.
Precision Medicine in Bladder Cancer: Present Challenges and Future Directions
Authors: Mohanty Sambit K. , Lobo Anandi , Mishra Sourav K. , Cheng Liang
Published: April 2023

Bladder cancer (BC) is characterized by significant histopathologic and molecular heterogeneity. The discovery of molecular pathways and knowledge of cellular mechanisms have grown exponentially and may allow for better disease classification, prognostication, and development of novel and more efficacious noninvasive detection and surveillance strategies, as well as selection of therapeutic targets, which can be used in BC, particularly in a neoadjuvant or adjuvant setting. This article outlines recent advances in the molecular pathology of BC with a better understanding and deeper focus on the development and deployment of promising biomarkers and therapeutic avenues that may soon make a transition into the domain of precision medicine and clinical management for patients with BC.
Management of Onsite and Remote Communication in Oncology Hospitals: Data Protection in an Era of Rapid Technological Advances
Authors: Mocydlarz-Adamcewicz Mirosława , Bajsztok Bartosz , Filip Stanislav , Petera Jiri , Mestan Miroslav , Malicki Julian
Published: April 2023

Modern communication and information technologies are rapidly being deployed at health care institutions around the world. Although these technologies offer many benefits, ensuring data protection is a major concern, and implementation of robust data protection measures is essential. In this context, health care providers and medical care facilities must frequently make difficult decisions and compromises between the need to provide effective medical care and the need to ensure data security and patient privacy. In the present paper, we describe and discuss key issues related to data protection systems in the setting of cancer care hospitals in Europe. We provide real-life examples from two European countries—Poland and the Czech Republic—to illustrate data protection issues and the steps being taking to address these questions. More specifically, we discuss the legal framework surrounding data protection and technical aspects related to patient authentication and communication.
Do Automated Market Makers in DeFi Ecosystem Exhibit Time-Varying Connectedness during Stressed Events?
Authors: Ghosh Bikramaditya , Kazouz Hayfa , Umar Zaghum
Published: April 2023

We investigate the connectedness of automated market makers (AMM) that play a pivotal role in liquidity and ease of operations in the decentralized exchange (DEX). By applying the TVP-VAR model, our findings show higher level of connectivity during periods of turmoil (such as Delta, Omicron variants of SARS-Covid, and the Russia Ukraine conflict). Furthermore, risk transmission/reception is found to be independent of the platform on which they typically run (Ethereum based AMMs were both emitters as well as receivers). Pancake (a Binance based AMM) and Perpetual Protocol (Ethereum based AMM) emerged as moderate to high receivers of risk transmission, whereas all of the other AMMs, including Ethereum, were found to be risk emitters at varying degrees. We argue that AMMs typically depend on the underlying smart contracts. If the contract is flexible, AMMs can vary (either receiver or emitter), otherwise AMMs behave in tandem.
Main Concepts in the Spoken Discourse of Persons with Aphasia: Analysis on a Propositional and Linguistic Level
Authors: Kuvač Kraljević Jelena , Matić Škorić Ana , Lice Karolina
Published: April 2023

Individuals produce discourse for various purposes as part of their daily functioning. Therefore, the ability to form a discourse should be one of the main goals of functional speech-language therapy for persons with aphasia (PwA). In addition to assessing the language skills required to form a discourse, it is important to analyse how PwA form general ideas that need to be narrated. This study had two specific aims: (1) to investigate the ability of PwA, with special consideration to the stage of their recovery—the acute and the chronic phase—to form main concepts in a discourse, and (2) to examine the relationship between the number of main concepts and different types of language measures related to productivity, informativeness, and grammaticality in all tested groups. Participants included a total of 38 persons with mild and moderate aphasia (19 in the acute and 19 in the chronic phase of recovery) and 38 healthy speakers (HS) who were matched in age, gender, and level of education. In order to effectively compare the discourse produced by the groups, a single structured stimulus was used, whereby all participants were asked to orally describe a picture from the Croatian version of the Comprehensive Aphasia Test. Compared to the HS, the main concepts produced by PwA were different in number, as well as in terms of their accuracy and completeness. However, when analysing the success in the production of the main concepts with regard to the time post-stroke—acute and chronic—the difference was not confirmed, indicating great individual differences between PwA that undermine the differences on a group level. Linguistic measures of informativeness (CIUs and CIU/words) and only one measure of grammaticality (number of clauses) showed a significant correlation with the number of main concepts in PwA. When analysing correlations for PwA in the acute and chronic phases, only CIU showed a significant association with MC, confirming it as a robust measure of discourse production in PwA. PwA did not produce long and complex sentences, and they showed difficulties in the use of verbs and the marking of argument structures.
Justice and Truth: A Leibnizian Perspective on Modern Jurisprudence
Authors: Armgardt Matthias
Published: April 2023

The purpose of this essay is to outline the significance of Leibniz’s philosophy of law for the present. The essay traces the main features of Leibniz’s theory and points out what further developments of his approach are pending today. Finally, it shows how similar Leibniz’s basic convictions are to those of Ronald Dworkin.
Physical Concept to Explain the Regulation of Lipid Membrane Phase Separation under Isothermal Conditions
Authors: Shimokawa Naofumi , Hamada Tsutomu
Published: April 2023

Lateral phase separation within lipid bilayer membranes has attracted considerable attention in the fields of biophysics and cell biology. Living cells organize laterally segregated compartments, such as raft domains in an ordered phase, and regulate their dynamic structures under isothermal conditions to promote cellular functions. Model membrane systems with minimum components are powerful tools for investigating the basic phenomena of membrane phase separation. With the use of such model systems, several physicochemical characteristics of phase separation have been revealed. This review focuses on the isothermal triggering of membrane phase separation from a physical point of view. We consider the free energy of the membrane that describes lateral phase separation and explain the experimental results of model membranes to regulate domain formation under isothermal conditions. Three possible regulation factors are discussed: electrostatic interactions, chemical reactions and membrane tension. These findings may contribute to a better understanding of membrane lateral organization within living cells that function under isothermal conditions and could be useful for the development of artificial cell engineering.
Synthesis and X-ray Structures of Potential Light-Harvesting Ruthenium(II) Complexes
Authors: Mariappan Kadarkaraisamy , Hussain Anwar , Nisly Nathaniel , Henning Tanner J. , Goerl Kathryn A. , Alaparthi Madhubabu , Sykes Andrew G.
Published: April 2023

We synthesized the luminescent ruthenium(II) polypyridyl complexes of type [Ru(bpy)2(L1)][ClO4]2 (1) (where L1 = 4,4-dicarboxy-2,2-bipyridine); [Ru(bpy)2(L2)][ClO4]2 (2); and [Ru(L2)3][ClO4]2 (3) (where L2 = 4,4-dimethanol-2,2-bipyridine). Photo-physical and electrochemical properties of the Ru(II) complexes were investigated along with the emission vs. pH. This reveals that the carboxylic acids in the 2,2-bipyridine ligand had a more important influence on the photophysical and electrochemical properties of the Ru(II) complexes than alcohol. The crystal structure of the Ru(II) complexes 1–3 is also discussed in this paper. The cyclic voltammetry of 1–3 yields a reversible RuIII/II wave that shifts 1.4–1.2 V. UV/Visible absorbance spectroscopy reveals that Metal-to-Ligand Charge Transfer (MLCT) transitions shift to lower energy upon deprotonation of the complex.
A Miniaturized and Highly Sensitive Microwave Sensor Based on CSRR for Characterization of Liquid Materials
Authors: Al-Gburi Ahmed Jamal Abdullah , Zakaria Zahriladha , Rahman Norhanani Abd , A. Althuwayb Ayman , Ibrahim Imran Mohd , Saeidi Tale , Dayo Zaheer Ahmed , Ahmad Sarosh
Published: April 2023

In this work, a miniaturized and highly sensitive microwave sensor based on a complementary split-ring resonator (CSRR) is proposed for the detection of liquid materials. The modeled sensor was designed based on the CSRR structure with triple rings (TRs) and a curve feed for improved measurement sensitivity. The designed sensor oscillates at a single frequency of 2.5 GHz, which is simulated using an Ansys HFSS simulator. The electromagnetic simulation explains the basis of the mode resonance of all two-port resonators. Five variations of the liquid media under tests (MUTs) are simulated and measured. These liquid MUTs are as follows: without a sample (without a tube), air (empty tube), ethanol, methanol, and distilled water (DI). A detailed sensitivity calculation is performed for the resonance band at 2.5 GHz. The MUTs mechanism is performed with a polypropylene tube (PP). The samples of dielectric material are filled into PP tube channels and loaded into the CSRR center hole; the E-fields around the sensor affect the relationship with the liquid MUTs, resulting in a high Q-factor value. The final sensor has a Q-factor value and sensitivity of 520 and 7.032 (MHz)/εr) at 2.5 GHz, respectively. Due to the high sensitivity of the presented sensor for characterizing various liquid penetrations, the sensor is also of interest for accurate estimations of solute concentrations in liquid media. Finally, the relationship between the permittivity and Q-factor value at the resonant frequency is derived and investigated. These given results make the presented resonator ideal for the characterization of liquid materials.
Shear Behavior of Reinforced Concrete Beam Retrofitted with Modularized Steel Plates
Authors: Kim Min Sook , Lee Young Hak
Published: April 2023

This paper presents the results of a shear test on a reinforced concrete beam retrofitted with modularized steel plates. A total of five retrofitted concrete beams with various span-depth ratios as a variable were fabricated and tested. A companion beam without retrofitting was used as the control specimen. The results of this experiment confirmed that the method proposed in this study improved the shear performance by approximately 1.8 times compared with the non-retrofitted reinforced concrete beam. The test results indicate that the shear retrofitting method using modularized steel plates can be effective in retrofitting the concrete beams, resulting in improvement in the strength, stiffness and deformations.
CFD–PBM Simulation for Continuous Hydrothermal Flow Synthesis of Zirconia Nanoparticles in a Confined Impinging Jet Reactor
Authors: Li Qingyun , Wang Zihua , Wang Xuezhong
Published: April 2023

Computational fluid dynamics (CFD) and population balance models (PBM) were coupled together for the first time to simulate the synthesis of zirconia nanoparticles in a continuous hydrothermal flow synthesis (CHFS) system with a self-designed confined impinging jet mixing (CJM) reactor. The hydrodynamic and thermodynamic behaviors within the CJM reactor strongly influenced the formation of the ZrO2 nanoparticles. Crucial parameters, such as velocities, temperatures, mixing conditions, and reaction rates, were analyzed under various supercritical conditions. Temperature and velocity measurements as functions of distance were also investigated. Normal particle size distribution (PSD) patterns were observed in all cases. The mean particle sizes in this study were calculated and compared using PBM aggregation analysis.
Microstructure, Texture, and Mechanical Properties of Friction Stir Spot-Welded AA5052-H32: Influence of Tool Rotation Rate
Authors: Ahmed Mohamed M. Z. , El-Sayed Seleman Mohamed M. , Albaijan Ibrahim , Abd El-Aty Ali
Published: April 2023

Friction stir spot welding (FSSW) of similar AA5052-H32 joints has numerous benefits in shipbuilding, aerospace, and automotive structural applications. In addition, studying the role of tool rotation speed on the microstructure features, achieved textures, and joint performance of the friction stir spot-welded (FSSWed) joint still needs more systematic research. Different FSSWed AA5052-H32 lap joints of 4 mm thickness were produced at different heat inputs using three tool rotation speeds of 1500, 1000, and 500 rpm at a constant dwell time of 2 s. The applied thermal heat inputs for achieving the FSSW processes were calculated. The produced joints were characterized by their appearance, macrostructures, microstructures, and mechanical properties (hardness contour maps and maximum tensile–shear load) at room temperature. The grain structure and texture developed for all the FSSWed joints were deeply investigated using an advanced electron backscattering diffraction (EBSD) technique and compared with the base material (BM). The main results showed that the average hardness value of the stir zone (SZ) in the welded joints is higher than that in the AA5052-H32 BM for all applied rotation speeds, and it decreases as the rotation speed increases from 500 to 1000 rpm. This SZ enhancement in hardness compared to the BM cold-rolled grain structure is caused by the high grain refining due to the dynamic recrystallization associated with the FSSW. The average grain size values of the stir zones are 11, 9, and 4 µm for the FSSWed joints processed at 1500, 1000, and 500 rpm, respectively, while the BM average grain size is 40 µm. The simple shear texture with B/-B components mainly dominates the texture. Compared to the welded joints, the joint processed at 500 rpm and a 2 s duration time attains the highest tensile-shear load value of 4330 N. This value decreases with increasing rotation speed to reach 2569 N at a rotation speed of 1500. After tensile testing of the FSSWed joints, the fracture surface was also examined and discussed.
Dislocation Substructures Evolution and an Informer Constitutive Model for a Ti-55511 Alloy in Two-Stages High-Temperature Forming with Variant Strain Rates in β Region
Authors: Tan Shen , He Daoguang , Lin Yongcheng , Zheng Bingkun , Wu Heyi
Published: April 2023

The high-temperature compression characteristics of a Ti-55511 alloy are explored through adopting two-stage high-temperature compressed experiments with step-like strain rates. The evolving features of dislocation substructures over hot, compressed parameters are revealed by transmission electron microscopy (TEM). The experiment results suggest that the dislocations annihilation through the rearrangement/interaction of dislocations is aggravated with the increase in forming temperature. Notwithstanding, the generation/interlacing of dislocations exhibit an enhanced trend with the increase in strain in the first stage of forming, or in strain rates at first/second stages of a high-temperature compressed process. According to the testing data, an Informer deep learning model is proposed for reconstructing the stress–strain behavior of the researched Ti-55511 alloy. The input series of the established Informer deep learning model are compression parameters (compressed temperature, strain, as well as strain rate), and the output series are true stresses. The optimal input batch size and sequence length are 64 and 2, respectively. Eventually, the predicted results of the proposed Informer deep learning model are more accordant with the tested true stresses compared to those of the previously established physical mechanism model, demonstrating that the Informer deep learning model enjoys an outstanding forecasted capability for precisely reconstructing the high-temperature compressed features of the Ti-55511 alloy.
Optimizing a Solution Heat Treatment by Increasing the Cooling Rate of Directional Solidification for Ni-Based Superalloys
Authors: Zhang Yanbin , Qin Ling , Zhu Bin , Jiang Haijun , Tan Li , Huang Taiwen , Gan Bin , Jie Ziqi , Liu Lin
Published: April 2023

The solution heat treatment (SHT) of the third generation of single crystal (SC) Ni-based superalloys required up to 45 h and was expensive. In this study, SHT based on liquid metal cooling (LMC) was optimized to greatly reduce processing time. The experimental and simulation results showed that residual segregation was evidently reduced, e.g., from 2.12 to 1.22 for the most heavily segregated Re. This led to a 16.7% increase in creep life, more uniform microstructures, and a decrease in solidification and homogenization porosity by a factor of 3.4. Structural refinement, approximately 0.32 times, served as the underlying mechanism for this optimization, which reduced diffusion distance and increased homogenization efficiency during SHT.
Structural Hierarchy of PA6 Macromolecules after Hydrostatic Extrusion
Authors: Skorupska Monika , Kulczyk Mariusz , Denis Piotr , Grzęda Dominik , Czajka Anna , Ryszkowska Joanna
Published: April 2023

This article presents the influence of severe plastic deformation by hydrostatic extrusion (HE) on the thermal and structural properties of polyamide 6 (PA6). During the hydrostatic extrusion process, a fibrous structure oriented along the extrusion direction is formed, which was visualized during microscopic observations. The degree of crystallinity was analyzed by differential scanning calorimetry (DSC). Wide-angle X-ray scattering diffraction (WAXS) analysis was used to partially characterize the PA6 structure after the HE process. The contents of various forms of the crystalline phase in PA6 samples before and after the HE process were analyzed in fragments of spectroscopy in infrared (FTIR). The favorable properties of PA6 after the HE process were obtained after deformation under conditions generating an adiabatic temperature higher than the glass transition temperature and lower than the temperature of the onset of melting of the crystalline phase. Thermal analysis using DSC allowed us to conclude that in the PA6 after the HE process generating deformations in the range of 0.68–1.56, the proportion of the crystalline phase α increases in PA6. As the deformation increases in the HE process, the crystalline phase proportion increases by 12% compared to the initial material (before HE). The glass transition temperature of PA6 is ca. 50.6 °C, reduced for the sample after the HE process at a small deformation of 0.68 (PA6_0.68) to ca. 44.2 °C. For other samples, Tg is ca. 53.2–53.5 °C. As a result of the analysis of WAXS diffractograms of PA6 samples after various deformations in the HE process, the presence of typical peaks of phases α1 and α2 and γ was observed. The results of the FTIR spectroscopic analysis confirm these observations that as the deformation increases, the proportion of the crystalline phase α increases.
Experimental Analysis of the Influence of Heat Treatments on the Flexibility of NiTi Alloy for Endodontic Instruments Manufacturing
Authors: Abdelmomen Ihssen , Vincent Marin , Thiebaud Frédéric , Budzinski Julia , Bastogne Thierry , Ben Zineb Tarak , Engels-Deutsch Marc
Published: April 2023

The flexibility of NiTi based endodontic files is improved by heat treatment, leading to lower risk of failure, ledges, and canal transportation during the preparation of curved root canals. The aim of this study is to investigate and clearly highlight the influence of every parameter of heat treatment on the flexibility of NiTi wires and thus of endodontic instruments. A full factorial Design of Experiment (DoE) and a designed bending–torsion bench following the ISO 3630-1 standard were used for this investigation. Temperature, holding time, and cooling method were selected as contributing factors, while maximum bending moment, hysteresis size, and stiffness during martensitic transformation were selected as outputs. Regression analysis was performed to estimate the relationship between contributing and output variables to assess how the experimentation fits with the model. The experimental results showed that wires heated at 425 °C for 30 min are more flexible. Moreover, heat treatment temperature is the most critical factor influencing the flexibility and hysteresis size of the NiTi wire followed by the holding time, while the cooling method has a negligible effect. The regression analysis showed that the model is effective at predicting the relationship between contributing factors, bending moment response, and hysteresis size.
Characterizing Tensile Strength of Building Sandstone via Uniaxial Tensile, Compressive, and Flexural Bending Tests
Authors: Guan Xiqiang , Huang Baofeng , Li Zhan , Ma Xiaofeng , Liang Benliang
Published: April 2023

Sandstone is widely used a construction and building material. However, its uniaxial tensile strength (UTS) is not adequately understood. To characterize the uniaxial tensile strength of natural sandstone, three groups of specimens were fabricated for four-point bending, uniaxial compressive, and tensile tests. To characterize the evolution of the stress–strain profiles obtained via these tests, representative expressions were developed in terms of normalized strain and strength. The magnitude of the uniaxial tensile strength exceeded that of the four-point bending strength, indicating that the uniaxial tensile strength cannot be represented by the four-point bending strength. The experimental ratio of uniaxial tensile and compression strength (33–41) was underestimated by the empirical expressions reported in the literature. The suggested correction coefficient for the FBS is 0.25. The compressive modulus (Ec) was generally identical to the experimental results published in the literature, whereas the tensile modulus (Et) was overestimated. The experimental modular ratio, Et/Ec, ranged from 0.12 to 0.14; it was not sensitive to Poisson’s ratio, but it increased slightly with the compressive modulus. This work can serve as a reference for computing the load-bearing capacity of sandstone components under tension.
Review of the Interactions between Conventional Cementitious Materials and Heavy Metal Ions in Stabilization/Solidification Processing
Authors: Liu Jingjing , Wu Dongbiao , Tan Xiaohui , Yu Peng , Xu Long
Published: April 2023

In the past few decades, solidification/stabilization (S/S) technology has been put forward for the purpose of improving soil strength and inhibiting contaminant migration in the remediation of heavy metal-contaminated sites. Cement, lime, and fly ash are among the most common and effective binders to treat contaminated soils. During S/S processing, the main interactions that are responsible for improving the soil’s behaviors can be summarized as gelification, self-hardening, and aggregation. Currently, precipitation, incorporation, and substitution have been commonly accepted as the predominant immobilization mechanisms for heavy metal ions and have been directly verified by some micro-testing techniques. While replacement of Ca2+/Si4+ in the cementitious products and physical encapsulation remain controversial, which is proposed dependent on the indirect results. Lead and zinc can retard both the initial and final setting times of cement hydration, while chromium can accelerate the initial cement hydration. Though cadmium can shorten the initial setting time, further cement hydration will be inhibited. While for mercury, the interference impact is closely associated with its adapted anion. It should be pointed out that obtaining a better understanding of the remediation mechanism involved in S/S processing will contribute to facilitating technical improvement, further extension, and application.
Insight into the Mechanism of Cobalt-Nickel Separation Using DFT Calculations on Ethylenediamine-Modified Silica Gel
Authors: Yang Hailun , Yuan Ling , Yuan Menglei , Ning Pengge
Published: April 2023

The separation of Co(II) and Ni(II) from leaching solution is gaining interest because Co(II) and Ni(II) are increasingly used in emerging strategic areas, such as power batteries. Herein, the surface of silica gel is functionalized with 1,2-ethylenediamine and used for the separation of Co(II) and Ni(II). The Co(II) removal efficiency of the modified silica is 80.2%, with a 4-fold improvement in the separation factor. The geometry, frequency, and electrostatic potential of the ethylenediamine modified silica gel (en/SG) are calculated. The corresponding properties of M2+ (M-Co, Ni) adsorbed on en/SG in an aqueous solution are simulated and analyzed. The results show that ethylenediamine tends to form [Men(H2O)4]2+ after binding to M2+, and the binding ability of Co(II) to ethylenediamine is stronger. Besides, the thermodynamic calculations show that en/SG has a more negative Gibbs free energy when absorbing Co(II) in aqueous solution, so en/SG is more inclined to bind with Co(II) preferentially. It is the difference in complexation ability between Ni, Co, and ethylenediamine that enlarges the difference in the original physical adsorption, thus strengthening the separation performance. This work will provide guidance for a rational design of high-performance nickel-cobalt adsorption materials.
Experimental Study and Numerical Analysis on the Shear Resistance of Bamboo Fiber Reinforced Steel-Wire-Mesh BFRP Bar Concrete Beams
Authors: Chen Wei , Qin Guohui , Luo Fei , Zhu Yuxian , Fu Gangrui , Yao Siqi , Ma Haohan
Published: April 2023

Bamboo fiber is a natural and environmentally friendly material made from cheap and widely available resources and is commonly selected as the reinforcement material for steel-wire-mesh BFRPbar concrete beams. In this work, the effects of various fiber lengths and fiber volume rates on the shear properties of bamboo-fiber-reinforced steel-wire-mesh basalt fiber composite reinforcement concrete beams were studied through a combination of shear tests and numerical simulations. The findings demonstrate that the addition of bamboo fiber improves the cracking performance of the beam. The improvement effect of 45 mm bamboo fiber mixed with a 1% volume rate was the most obvious at about 31%. Additionally, the test beam’s total stiffness was increased, and the deflection was decreased. However, the use of bamboo fiber was found to decrease the concrete’s compressive strength, lowering the final shear capacity for the majority of beams. A method for estimating the shear capacity of the bamboo-fiber-reinforced steel-wire-mesh BFRPbar concrete beams is provided and lays the foundation for engineering practice, in accordance with the impact of bamboo fiber and steel wire mesh on beams that suffer shear breaks.
Rational Design, Stabilities and Nonlinear Optical Properties of Non-Conventional Transition Metalides; New Entry into Nonlinear Optical Materials
Authors: Alkhalifah Mohammed A. , Sheikh Nadeem S. , Al-Faiyz Yasair S. S. , Bayach Imene , Ludwig Ralf , Ayub Khurshid
Published: April 2023

Electronic and nonlinear optical properties of endohedral metallofullerenes are presented. The endohedral metallofullerenes contain transition metal encapsulated in inorganic fullerenes X12Y12 (X = B, Al & Y = N, P). The endohedral metallofullerenes (endo-TM@X12Y12) possess quite interesting geometric and electronic properties, which are the function of the nature of the atom and the size of fullerene. NBO charge and frontier molecular orbital analyses reveal that the transition metal encapsulated Al12N12 fullerenes (endo-TM@Al12N12) are true metalides when the transition metals are Ni, Cu and Zn. Endo-Cr@Al12N12 and endo-Co@Al12N12 are at the borderline between metalides and electrides with predominantly electride characteristics. The other members of the series are excess electron systems, which offer interesting electronic and nonlinear optical properties. The diversity of nature possessed by endo-TM@Al12N12 is not prevalent for other fullerenes. Endo-TM@Al12P12 are true metalides when the transition metals are (Cr-Zn). HOMO-LUMO gaps (EH-L) are reduced significantly for these endohedral metallofullerenes, with a maximum percent decrease in EH-L of up to 70%. Many complexes show odd–even oscillating behavior for EH-L and dipole moments. Odd electron species contain large dipole moments and small EH-L, whereas even electron systems have the opposite behavior. Despite the decrease in EH-L, these systems show high kinetic and thermodynamic stabilities. The encapsulation of transition metals is a highly exergonic process. These endo-TM@X12Y12 possess remarkable nonlinear optical response in which the first hyperpolarizability reaches up to 2.79 × 105 au for endo-V@Al12N12. This study helps in the comparative analysis of the potential nonlinear optical responses of electrides, metalides and other excess electron systems. In general, the potential nonlinear optical response of electrides is higher than metalides but lower than those of simple excess electron compounds. The higher non-linear optical response and interesting electronic characteristics of endo-TM@Al12N12 complexes may be promising contenders for potential NLO applications.
Determination and Calculations of Mercury Vapor Concentration and Energy Released from Freshly Condensed Dental Amalgams Having Various Copper Percentages within the Alloy
Authors: Moxon Ryan , Xu Zhigang , Chris-Okoro Ikenna , Cherono Sheilah , Kumar Dhananjay
Published: April 2023

Dental amalgam is an alloy consisting of a mixture of fine metallic powder of silver, tin, zinc, copper, and a trace amount of palladium in combination with about fifty percent elemental mercury that forms a matrix phase. Dental amalgams consisting of a high-copper content are the most common types of alloys currently utilized for the restoration of decayed, broken, and fractured posterior human teeth. The present research objective was primarily to improve the material properties by determining and analyzing the amount of mercury vapor released from dental amalgam received from eight different commercial brands. The mechanical hardness of the alloys was found to increase with an increase in copper content in the amalgam. The effect of copper addition on material aging was also studied. During the release of mercury vapor, the corresponding energies associated with the release of mercury vapor from each sample were determined for each successive measurement. The results indicated that increasing the copper content of the amalgam counters the release of mercury vapor from posterior teeth and improves the hardness properties.
Uncovering the Mechanism of the Role of Fly Ash in the Self-Healing Ability of Mortar with Different Curing Ages
Authors: Luan Congqi , Yuan Lianwang , Wang Jinbang , Zhou Zonghui
Published: April 2023

As an admixture of cement-based materials, the reaction of fly ash (FA) usually takes place in the late age of curing, so FA will affect the self-healing ability of long-age cement-based materials. The self-healing potential and the characteristics of self-healing products of cementitious materials before and after crack healing were analyzed by microscopic tests, and the mechanism of the effect of fly ash on the self-healing performance of cementitious materials was revealed. The results showed that the increase in fly ash content promoted the improvement of the self-repair performance of cracked specimens at 28 d, especially when the fly ash dosage was 40%, the crack opened after 30 d of healing in water was completely closed, the UPV value after recovery was close to 3000 m/s, the self-repair efficiency of maximum amplitude and main frequency amplitude was up to more than 60%, and the recovery rate of compressive strength was increased to more than 30%. However, the increase in fly ash content was not conducive to the self-repair of cracked samples at 210 d, and with the increase in fly ash content, the crack closure effect weakened, the UPV value after recovery decreased, the crack repair rate based on ultrasonic transmission decreased to about 20%, and the compressive strength recovery rate increased slightly. In addition, calcium carbonate precipitation was the main repair product of crack filling and healing, including calcite and spherulite. With the increase in fly ash content, the content of element C in the self-repair products of 28-day-old specimens gradually increased, and the size of calcium carbonate crystals gradually decreased, but the filling was denser, whereas the calcium carbonate crystals in the self-repair products of 210 d specimens gradually became fine and loose.
Improving the Surface Integrity of 316L Steel in the Context of Bioimplant Applications
Authors: Szwajka Krzysztof , Zielińska-Szwajka Joanna , Trzepieciński Tomasz
Published: April 2023

Bioimplants should meet important surface integrity criteria, with the main goal of the manufacturing process to improve wear and corrosion resistance properties. This requires a special approach at the cutting stage. During this research, the impact of the cutting parameters on improving the surface integrity of AISI 316L steel was evaluated. In this context of bioimplant applications, the mean roughness Sa value was obtained in the range of 0.73–4.19 μm. On the basis of the results obtained, a significant effect was observed of both the cutting speed and the feed rate on changes in the microstructure of the near-surface layer. At a cutting speed of 150 m/min, the average grain size was approximately 31 μm. By increasing the cutting speed to 200 m/min, the average grain size increased to approximately 52 μm. The basic austenitic microstructure of AISI 316L steel with typical precipitation of carbides on the grain boundaries was refined at the near-surface layer after the machining process. Changing the cutting speed determined the hardness of the treated and near-surface layers. The maximum value of hardness is reached at a depth of 20 μm and decreases with the depth of measurement. It was also noted that at a depth of up to 240 μm, the maximum hardness of 270–305 HV1 was reached, hence the height of the machining impact zone can be determined, which is approximately 240 μm for almost all machining conditions.
Colorless Polyimides Derived from Octahydro-2,3,6,7-anthracenetetracarboxylic Dianhydride
Authors: Hasegawa Masatoshi , Sato Hiroki , Hoshino Katsuhisa , Arao Yasuhisa , Ishii Junichi
Published: April 2023

A cycloaliphatic tetracarboxylic dianhydride, octahydro-2,3,6,7-anthracenetetracarboxylic dianhydride (OHADA) was synthesized to obtain novel colorless polyimides (PIs). Herein, approaches for decolorizing an OHADA prototype and simplifying the entire process are described, and a plausible steric structure for OHADA is proposed. The polyaddition of OHADA and 2,2′-bis(trifluoromethyl)benzidine (TFMB) was unsuccessful; specifically, the reaction mixture remained inhomogeneous even after prolonged stirring. However, the modified one-pot process was applicable to the OHADA/TFMB system. The isolated PI powder form, as well as those for the other OHADA-based PIs, was highly soluble in numerous solvents and afforded a homogeneous and stable solution with a high solid content (20–30 wt%). Solution casting produced a colorless and ductile PI film with a very high glass transition temperature (Tg~300 °C). Furthermore, the OHADA/TFMB system exhibited remarkable thermal stability compared with those of the other related TFMB-derived semi-cycloaliphatic PIs. However, contrary to our expectations, this PI film did not exhibit a low linear coefficient of thermal expansion (CTE). This PI film also possessed excellent thermoplasticity, probably reflecting its peculiar steric structure. The use of an amide-containing diamine significantly enhanced the Tg (355 °C) and somewhat reduced the CTE (41.5 ppm K−1) while maintaining high optical transparency and excellent solubility.
Superconducting Gap Structure of Filled Skutterudite LaOs4As12 Compound through μSR Investigations
Authors: Bhattacharyya Amitava , Adroja Devashibhai T. , Hillier Adrian D. , Biswas Pabitra Kumar
Published: April 2023

Filled skutterudite compounds have gained attention recently as an innovative platforms for studying intriguing low-temperature superconducting properties. Regarding the symmetry of the superconducting gap, contradicting findings from several experiments have been made for LaRu4As12 and its isoelectronic counterpart, LaOs4As12. In this vein, we report comprehensive bulk and microscopic results on LaOs4As12 utilizing specific heat analysis and muon-spin rotation/relaxation (μSR) measurements. Bulk superconductivity with TC = 3.2 K was confirmed by heat capacity. The superconducting ground state of the filled-skutterudite LaOs4As12 compound is found to have two key characteristics: superfluid density exhibits saturation type behavior at low temperature, which points to a fully gapped superconductivity with gap value of 2Δ/kBTC = 3.26; additionally, the superconducting state does not show any sign of spontaneous magnetic field, supporting the preservation of time-reversal symmetry. These results open the door for the development of La-based skutterudites as special probes for examining the interplay of single- and multiband superconductivity in classical electron–phonon systems.
A Moment Approach for a Conditional Central Limit Theorem of Infinite-Server Queue: A Case of M/MX/∞ Queue
Authors: Nakamura  Ayane , Phung-Duc  Tuan
Published: April 2023

Several studies have been conducted on scaling limits for Markov-modulated infinite-server queues. To the best of our knowledge, most of these studies adopt an approach to prove the convergence of the moment-generating function (or characteristic function) of the random variable that represents a scaled version of the number of busy servers and show the weak law of large numbers and the central limit theorem (CLT). In these studies, an essential assumption is the finiteness of the phase process and, in most of them, the CLT for the number of busy servers conditional on the phase (or the joint states) has not been considered. This paper proposes a new method called the moment approach to address these two limitations in an infinite-server batch service queue, which is called the M/MX/∞ queue. We derive the conditional weak law of large numbers and a recursive formula that suggests the conditional CLT. We derive series expansion of the conditional raw moments, which are used to confirm the conditional CLT by a symbolic algorithm.
Eagle-YOLO: An Eagle-Inspired YOLO for Object Detection in Unmanned Aerial Vehicles Scenarios
Authors: Liao Lyuchao , Luo Linsen , Su Jinya , Xiao Zhu , Zou Fumin , Lin Yuyuan
Published: April 2023

Object detection in images taken by unmanned aerial vehicles (UAVs) is drawing ever-increasing research interests. Due to the flexibility of UAVs, their shooting altitude often changes rapidly, which results in drastic changes in the scale size of the identified objects. Meanwhile, there are often many small objects obscured from each other in high-altitude photography, and the background of their captured images is also complex and variable. These problems lead to a colossal challenge with object detection in UAV aerial photography images. Inspired by the characteristics of eagles, we propose an Eagle-YOLO detection model to address the above issues. First, according to the structural characteristics of eagle eyes, we integrate the Large Kernel Attention Module (LKAM) to enable the model to find object areas that need to be focused on. Then, in response to the eagle’s characteristic of experiencing dramatic changes in its field of view when swooping down to hunt at high altitudes, we introduce a large-sized feature map with rich information on small objects into the feature fusion network. The feature fusion network adopts a more reasonable weighted Bi-directional Feature Pyramid Network (Bi-FPN). Finally, inspired by the sharp features of eagle eyes, we propose an IoU loss named Eagle-IoU loss. Extensive experiments are performed on the VisDrone2021-DET dataset to compare it with the baseline model YOLOv5x. The experiments showed that Eagle-YOLO outperformed YOLOv5x by 2.86% and 4.23% in terms of the mAP and AP50, respectively, which demonstrates the effectiveness of Eagle-YOLO for object detection in UAV aerial image scenes.
Comparison of Different Machine Learning Models for Modelling the Higher Heating Value of Biomass
Authors: Brandić Ivan , Pezo Lato , Bilandžija Nikola , Peter Anamarija , Šurić Jona , Voća Neven
Published: April 2023

The aim of this study was to investigate the potential of using structural analysis parameters for estimating the higher heating value (HHV) of biomass by obtaining information on the composition of cellulose, lignin, and hemicellulose. To achieve this goal, several nonlinear mathematical models were developed, including polynomials, support vector machines (SVMs), random forest regression (RFR) and artificial neural networks (ANN) for predicting HHV. The performed statistical analysis “goodness of fit” showed that the ANN model has the best performance in terms of coefficient of determination (R2 = 0.90) and the lowest level of model error for the parameters X2 (0.25), RMSE (0.50), and MPE (2.22). Thus, the ANN model was identified as the most appropriate model for determining the HHV of different biomasses based on the specified input parameters. In conclusion, the results of this study demonstrate the potential of using structural analysis parameters as input for HHV modeling, which is a promising approach for the field of biomass energy production. The development of the model ANN and the comparative analysis of the different models provide important insights for future research in this field.
Distributed Finite-Time Cooperative Economic Dispatch Strategy for Smart Grid under DOS Attack
Authors: Song Zhenghang , Wang Xiang , Wei Baoze , Shan Zhengyu , Guan Peiyuan
Published: April 2023

This paper proposes an energy management strategy that can resist DOS attacks for solving the Economic Dispatch Problem (EDP) of the smart grid. We use the concept of energy agent, which acts as a hub for the smart grid, and each EA is an integrated energy unit that converts, stores, and utilizes its local energy resources. This approach takes into account the coupling relationship between energy agents (EA) and utilizes the Lyapunov function technique to achieve finite-time solutions for optimization problems. We incorporate strategies to resist DOS attacks when analyzing finite-time convergence using the Lyapunov technique. Based on this, a finite convergence time related to DOS attack time is derived. The integral sliding mode control strategy is adopted and the Lyapunov method is used to analyze it, so that the algorithm can resist DOS attacks and resist external disturbances. Through theoretical analysis, it is shown that the strategy is capable of converging to the global optimal solution in finite time even if it is attacked by DOS. We conducted case studies of six-EA and ten-EA systems to verify the effectiveness of this strategy. The proposed strategy has potential for deployment in distributed energy management systems that require resilience against DOS attacks.