bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of the Impact of Population Reduction on Grasslands with a New “Tool”: A Case Study on the “Mountainous Banat” Area of Romania
Authors: Cojocariu Luminiţa L. , Copăcean Loredana , Ursu Adrian , Sărăţeanu Veronica , Popescu Cosmin A. , Horablaga Marinel N. , Bordean Despina-Maria , Horablaga Adina , Bostan Cristian
Published: January 2024

The landscapes and, implicitly, the surfaces of secondary grasslands in the mountain areas have been intensively modified and transformed by humans. In this context, this paper analyses the spatial and temporal changes of grassland surfaces following the impact of human population reduction. Thus, the study proposes the implementation of the Grassland Anthropic Impact Index (GAII) as a “measurement tool” to functionally link the two components, grassland surface and human population. The spatiotemporal analyses are based on Corine Land Cover data and demographic data, processed via Geographic Information Systems (GIS) methods and the Land Change Modeler (LCM) tool. The research shows that over a period of 28 years, the population, which was continuously decreasing, caused a series of transformations to the grasslands over an area of 33343 ha. The influence of the reduction in the number of inhabitants was also demonstrated by the direction of the changes produced in the grassland surfaces: in the better populated areas, the grasslands expanded over lands with other uses, and in the sparsely populated areas, they were abandoned. GAII values generally increase with the decrease of the population in the target area, meaning that for an inhabitant (potential user) a greater grassland surface is reported, resulting in a greater responsibility for the management of this resource on a space and time scale. Following the evaluation of the trend of the last 28 years, it was observed that the depopulation of mountain areas can be seen as a threat to grassland ecosystems, either through the transition to other categories of use, or through abandonment. The implications of these phenomena are much broader: they produce chain reactions and affect other components of the regional geosystem.
New Approaches to Spanish Dialectal Grammar: Guest Editor’s Introduction
Authors: Pato Enrique
Published: January 2024

If we understand Language as everything that is selected, numbered, merged and sent, and Grammar (both of the language and of the individual) as the union of Lexicon and Syntax, we share the same theoretical vision [...]
Genetic Analysis of Adaptive Traits in Spring Wheat in Northeast China
Authors: Zhang Hongji , Li Yuyao , Liu Wenlin , Sun Yan , Tang Jingquan , Che Jingyu , Yang Shuping , Wang Xiangyu , Zhang Rui
Published: January 2024

The dissection of the genetic architecture and the detection of the loci for adaptive traits are important for marker-assisted selection (MAS) for breeding. A spring wheat diversity panel with 251 cultivars, mainly from China, was obtained to conduct a genome-wide association study (GWAS) to detect the new loci, including the heading date (HD), maturating date (MD), plant height (PH), and lodging resistance (LR). In total, 41 loci existing in all 21 chromosomes, except for 4A and 6B, were identified, and each explained 4.3–18.9% of the phenotypic variations existing in two or more environments. Of these, 13 loci are overlapped with the known genes or quantitative trait loci (QTLs), whereas the other 28 are likely to be novel. The 1A locus (296.9–297.7 Mb) is a multi-effect locus for LR and PH, whereas the locus on chromosome 6D (464.5–471.0 Mb) affects both the HD and MD. Furthermore, four candidate genes for adaptive traits were identified, involved in cell division, signal transduction, and plant development. Additionally, two competitive, allele-specific PCR (KASP) markers, Kasp_2D_PH for PH and Kasp_6D_HD for HD, were developed and validated in another 162 spring wheat accessions. Our study uncovered the genetic basis of adaptive traits and provided the associated SNPs and varieties with more favorable alleles for wheat MAS breeding.
Metabolomic Profile of Arthrospira platensis from a Bulgarian Bioreactor—A Potential Opportunity for Inclusion in Dietary Supplements
Authors: Nikolova Krastena , Gentscheva Galia , Gyurova Desislava , Pavlova Vera , Dincheva Ivayla , Velikova Margarita , Gerasimova Anelia , Makedonski Lubomir , Gergov Georgi
Published: January 2024

The present study aims to elucidate the metabolomic profile of Arthrospira platensis grown in a bioreactor in Bulgaria. The results show that Arthrospira platensis has a high content of mannose, 137.02 mg g−1, and vitamin A (retinol)—10.3 μg/100 g. High concentrations of calcium, sulfur, and zinc distinguish its elemental composition. The freeze-dried powder contained 15.81 ± 0.45% dietary fiber, 50.16 ± 0.25% total protein content, and 1.22 ± 0.11% total fat content. Among the unsaturated fatty acids with the highest content is α-linolenic acid (25.28%), while among the saturated fatty acids, palmitic acid prevails (22.55%). Of the sterols in the sample, β-sitosterol predominated. There is no presence of microcystins LR, RR, YR, and nodularin. Therefore, Arthrospira platensis grown in a Bulgarian bioreactor is safe for use in the pharmaceutical and food industries. Many of the organic compounds found have applications in medicine and pharmacology and play an important role in biochemical processes in the body. Therefore, Arthrospira platensis grown in Bulgaria has a high potential for use as an independent food supplement or in combination with other natural products.
Characteristics of Two Lagoons in the Coastal Area of the Baltic Sea
Authors: Purmalis Oskars , Grinberga Laura , Dobkevica Linda , Skuja Agnija , Ozolins Davis , Druvietis Ivars , Ozols Viesturs , Paidere Jana
Published: January 2024

The proposed study is focused on an ecological analysis of Latvian coastal lagoons, emphasizing their unique but vulnerable nature. Coastal lagoons are recognized as fragile ecosystems of significant ecological, social, and economic value, as recognized by the European Directive 92/43/EEC (Habitats Directive). Despite their protected status, the existence of these ecosystems can be threatened by morphological, hydrological, and anthropogenic changes. The uniqueness of these ecosystems can be determined by the large number of influencing factors and their dynamics. They are affected by seawater, their level of fluctuation, wind exposure, overgrowing with macrophytes, freshwater sources, and water flow generated streams affecting sediment transport and accumulation. All the influencing factors determine a highly trophic ecosystem, which in the studied lagoons is rated as medium to poor ecological status, which confirms the above-mentioned vulnerability and fragility. The aim of this study was to analyze two lagoons in the coastal area of the Baltic Sea in the Riga Gulf, by characterizing, for the first time, their current conditions and ecological parameters because understanding such ecosystems is only partial. The physicochemical composition of lagoon sediments and water shows the impact of seawater by increased electrical conductivity and the concentration of SO42− and Cl− in water, while the presence of detritus in sediments is almost non-existent; thus, the content of organic matter is low with relatively variable pH. The results show that the diversity of studied benthic macroinvertebrates, macrophytes, zooplankton, and even phytoplankton species is low, but there is higher diversity in lagoons and their parts with regular water exchange with the sea. The study provides valuable insight into the ecological dynamics of coastal lagoons in Latvia, shedding light on their current conditions, anthropogenic impact, and the need for sustainable management measures.
Coarse-Grained Molecular Dynamics Simulations of Organic Friction Modifier Adsorption on Rough Surfaces under Shear
Authors: Tang Jiahao , Chong William Woei Fong , Zhang Hedong
Published: January 2024

Reducing friction energy losses is crucial in mechanical systems, often achieved through lubrication strategies employing friction modifiers. These additives adsorb onto surfaces, forming boundary film to prevent solid–solid contacts. However, atomistic simulation techniques used to study these additives often ignore surface roughness due to high computational cost. This study addresses this gap by employing Coarse-Grained Molecular Dynamics (CG MD) to investigate the impact of surface roughness on the adsorption of Organic Friction Modifiers (OFMs) under shear. Traditional self-diffusion methods prove inadequate for determining the damping coefficients in CG models because of strong OFM adsorption effects. Therefore, shear-induced motion is introduced for the coefficient determination. The simulation reveals that a symmetrical model (identical opposing surfaces) shows OFM slip, desorption, and re-adsorption trends on rough surfaces, while an asymmetrical model (smooth cylinder on a flat surface) demonstrates increased adsorption on rough flat surfaces (up to 60.9%) compared to smooth flat surfaces under similar shearing conditions. However, rough flat surfaces with a smaller wavelength (6 nm) exhibit faster OFM desorption along the asperity region, up to four times more than a 24 nm wavelength surface. This research emphasizes the importance of considering surface roughness in simulating OFM behavior for lubrication applications.
The Utilization of a Damping Structure in the Development of Self-Adaptive Water-Lubricated Stern Bearings
Authors: Liu Yong , Zhou Yingzhi , He Tao , Xia Yang
Published: January 2024

A novel water-lubricated stern bearing damping structure with self-adaptive performance is proposed to meet the load-balancing and vibration-damping requirements of water-lubricated bearings. This innovative damping structure comprises an elastic element and a damping alloy layer. The elastic element facilitates the static and dynamic load sharing of the stern bearing, mitigates the edge effects, ensures even distribution of the contact pressure along the axial direction, and enhances the overall bearing performance. Consequently, it prolongs the service life of the bearing and minimizes friction-induced stimulation. The damping alloy layer effectively attenuates the transmission of shafting vibrations to the foundation through the bearing, optimizing the vibration transmission characteristics. Leveraging the finite element model, an in-depth analysis of the compensation capability of the turning angle and damping performance of the adaptive stern bearing was conducted. The findings reveal that when the thickness of the elastic element is increased from 10 mm to 40 mm, the maximum contact pressure can be reduced by 12.53%. When the length ratio of the elastic element is reduced from 0.7 to 0.4, the maximum contact pressure is reduced by 12.42%. Therefore, increasing the thickness and decreasing the length of the elastic element in the adaptive damping device enhance the load performance, improve the compensation capabilities, and reduce the bearing wear, thereby promoting greater bearing uniformity. Furthermore, the adaptive vibration-damping device optimizes the vibration transmission characteristics from the propeller stimulation to the bearing node. The computational results demonstrate a noteworthy reduction in the speed, acceleration, and displacement responses at the first-order natural frequency, decreasing by 58.82%, 58.90%, and 58.86%, respectively. This substantial reduction in the vibration response at the first-order natural frequency signifies the effective mitigation of vibrations in the system.
Vastness of Tribology Research Fields and Their Contribution to Sustainable Development
Authors: Ciulli Enrico
Published: January 2024

Tribology is related to all studies on friction, wear, and lubrication. One of the main aims of these studies is a reduction in friction and wear. Tribology is extremely vast, being also multidisciplinary and interdisciplinary. Therefore, it is very difficult to organize the several tribology subjects in an unique way and different classifications have been proposed by different authors. In this work, several subjects treated by tribology are reviewed and organized in six branches: Fundamental Tribology, Tribology of Materials and Lubricants, Micro and Nanotribology, Industrial Tribology, Biotribology, and New Frontiers of Tribology. The main subjects treated by the six branches are briefly reviewed in this paper in order to highlight the vastness of tribology and its important contribution to sustainability. Particularly, friction and wear reductions are strictly related to greater efficiency and material saving, which means less energy losses and material wastes, less pollution and therefore a more sustainable life according to the sustainable development goals. The connections among the latter and the several different tribological subjects are discussed.
Cryogenic Treatment of Martensitic Steels: Microstructural Fundamentals and Implications for Mechanical Properties and Wear and Corrosion Performance
Authors: Jurči Peter , Dlouhý Ivo
Published: January 2024

Conventional heat treatment is not capable of converting a sufficient amount of retained austenite into martensite in high-carbon or high-carbon and high-alloyed iron alloys. Cryogenic treatment induces the following alterations in the microstructures: (i) a considerable reduction in the retained austenite amount, (ii) formation of refined martensite coupled with an increased number of lattice defects, such as dislocations and twins, (iii) changes in the precipitation kinetics of nano-sized transient carbides during tempering, and (iv) an increase in the number of small globular carbides. These microstructural alterations are reflected in mechanical property improvements and better dimensional stability. A common consequence of cryogenic treatment is a significant increase in the wear resistance of steels. The current review deals with all of the mentioned microstructural changes as well as the variations in strength, toughness, wear performance, and corrosion resistance for a variety of iron alloys, such as carburising steels, hot work tool steels, bearing and eutectoid steels, and high-carbon and high-alloyed ledeburitic cold work tool steels.
Influence of Service Conditions and Mix Design on the Physical–Mechanical Properties of Roller-Compacted Concrete for Pavement
Authors: Pulecio-Díaz Julián , Sol-Sánchez Miguel , Moreno-Navarro Fernando
Published: January 2024

This research focuses on the behavior of roller-compacted concrete (RCC) used in pavements, which are prone to deterioration affecting their performance. These deteriorations result from various causes, including traffic load, errors during construction, mix design, and ambient conditions. Among these, ambient conditions could lead to a marked variable impact on material behavior and durability depending on the conditions associated with each region. Accordingly, this study aims to deepen the understanding of the effect, which a broader range of ambient conditions and different mix designs have on the physical and mechanical properties of RCC. Measurements such as the amount of water vapor per kilogram of air were used to apply the findings comprehensively. The RCC analysis encompassed experimentation with different compositions, altering the cement water ratio amount, and adding a superplasticizer. The impact of curing on the materials was evaluated before subjecting them to various humidity and temperature conditions. Laboratory tests were conducted to measure performance, including moisture, shrinkage, compressive strength, and the progression of flexural fracture resistance over curing periods of up to 90 days. The results revealed a logarithmic correlation between shrinkage and ambient humidity, which is the most determining factor in performance. Mix optimization through increased cement and reduced water enhanced the tensile strength of the material. Furthermore, the curing process was confirmed to increase resistance to shrinkage, especially in the long term, establishing it as a crucial element for the structural stability of RCC, which is relatively insensitive to variations in ambient conditions.
Current State Analysis of Croatian Manufacturing Industry with Regard to Industry 4.0/5.0
Authors: Mladineo Marko , Celent Luka , Milković Vili , Veža Ivica
Published: January 2024

It has been more than a decade since the introduction of the Industry 4.0 paradigm. Since then, many issues have been raised in the world: the COVID-19 pandemic, sustainable development goals, and recent dramatic changes in global politics. The global value chains were broken during the pandemic, and the importance of humans as the most important element of the production system was highlighted. It caused rethinking about current industrial paradigms, including the brand new paradigm of Industry 4.0. More focus has been put on human workers, sustainability, and the resilience of the value chain, so the Industry 4.0 update was presented as Industry 5.0. A specific methodology to evaluate the maturity level of the manufacturing industry with regard to Industry 4.0/5.0 is presented and tested in the Croatian manufacturing industry. The developed methodology is unique since it puts Industry 5.0 in the right context with Industry 4.0. Therefore, the Industry 4.0 index remains the main indicator; however, alignment with three Industry 5.0 aims (human-centricity, sustainability, and resilience) represents three additional indicators. The results of the current state analysis are presented as a case study with a discussion about the results and methodology itself.
Numerical Approximation for a Stochastic Fractional Differential Equation Driven by Integrated Multiplicative Noise
Authors: Hoult James , Yan Yubin
Published: January 2024

We consider a numerical approximation for stochastic fractional differential equations driven by integrated multiplicative noise. The fractional derivative is in the Caputo sense with the fractional order α∈(0,1), and the non-linear terms satisfy the global Lipschitz conditions. We first approximate the noise with the piecewise constant function to obtain the regularized stochastic fractional differential equation. By applying Minkowski’s inequality for double integrals, we establish that the error between the exact solution and the solution of the regularized problem has an order of O(Δtα) in the mean square norm, where Δt denotes the step size. To validate our theoretical conclusions, numerical examples are presented, demonstrating the consistency of the numerical results with the established theory.
Assessing Strategies to Overcome Barriers for Drone Usage in Last-Mile Logistics: A Novel Hybrid Fuzzy MCDM Model
Authors: Tadić Snežana , Krstić Mladen , Radovanović Ljubica
Published: January 2024

Effective last-mile (LM) delivery is critical to the efficient functioning of supply chains. In addition to speed and the cost of delivery, environmental and social sustainability are increasingly important factors in last-mile logistics (LML), especially in urban areas. Sustainable solutions such as drones attract special attention from researchers due to their high potential. The future of drone logistics is uncertain due to many barriers. This study analyzes, evaluates and ranks barriers to identify those that most significantly hinder broader drone adoption in LML, and proposes and ranks strategies to overcome them. This type of issue requires the involvement of multiple stakeholders with conflicting goals and interests. Therefore, the study employs a novel hybrid multi-criteria decision-making (MCDM) model that combines fuzzy Delphi-based fuzzy factor relationship (Fuzzy D-FARE) and fuzzy comprehensive distance-based ranking (Fuzzy COBRA) methods. The results indicate that the main obstacle to drone implementation in LM is the lack of aviation regulations. The risks of unauthorized access, data misuse, privacy breaches, and data security represent significant challenges. They are followed by ambiguously defined or burdensome requirements for insurance and liability for drone owners. The main contributions of this study are the establishment of a novel hybrid model, identification and ranking of barriers for broader application of drones in LML, and strategies for overcoming them.
A Community Detection and Graph-Neural-Network-Based Link Prediction Approach for Scientific Literature
Authors: Liu Chunjiang , Han Yikun , Xu Haiyun , Yang Shihan , Wang Kaidi , Su Yongye
Published: January 2024

This study presents a novel approach that synergizes community detection algorithms with various Graph Neural Network (GNN) models to bolster link prediction in scientific literature networks. By integrating the Louvain community detection algorithm into our GNN frameworks, we consistently enhanced the performance across all models tested. For example, integrating the Louvain model with the GAT model resulted in an AUC score increase from 0.777 to 0.823, exemplifying the typical improvements observed. Similar gains were noted when the Louvain model was paired with other GNN architectures, confirming the robustness and effectiveness of incorporating community-level insights. This consistent increase in performance—reflected in our extensive experimentation on bipartite graphs of scientific collaborations and citations—highlights the synergistic potential of combining community detection with GNNs to overcome common link prediction challenges such as scalability and resolution limits. Our findings advocate for the integration of community structures as a significant step forward in the predictive accuracy of network science models, offering a comprehensive understanding of scientific collaboration patterns through the lens of advanced machine learning techniques.
Impact of Geopolitical Risk on G7 Financial Markets: A Comparative Wavelet Analysis between 2014 and 2022
Authors: Panazan Oana , Gheorghe Catalin
Published: January 2024

This study investigates co-movements between the GPR generated by the Crimean Peninsula’s annexation in 2014, the Russia–Ukraine war in 2022, and the volatility of stock markets in the G7 states. Using wavelet analysis, concentrated co-movement was found for all indices in both periods. Contrary to the general perception, we find that the G7 financial market response in 2014 was robust. Using a time-varying parameter vector autoregression (TVP-VAR) test, we found a larger reaction in the amplitude of the G7 financial markets in 2022 than in 2014. The financial markets in France, Germany, and the UK showed a similar reaction in 2022. We have identified some common aspects, even if the political and military contexts of the two studied events were completely different. Our findings offer new and interesting implications for understanding how geopolitical risk affects financial assets for market participants with multiple investment horizons and strategies.
Multi-Target Feature Selection with Adaptive Graph Learning and Target Correlations
Authors: Zhou Yujing , He Dubo
Published: January 2024

In this paper, we present a novel multi-target feature selection algorithm that incorporates adaptive graph learning and target correlations. Specifically, our proposed approach introduces the low-rank constraint on the regression matrix, allowing us to model both inter-target and input–output relationships within a unified framework. To preserve the similarity structure of the samples and mitigate the influence of noise and outliers, we learn a graph matrix that captures the induced sample similarity. Furthermore, we introduce a manifold regularizer to maintain the global target correlations, ensuring the preservation of the overall target relationship during subsequent learning processes. To solve the final objective function, we also propose an optimization algorithm. Through extensive experiments on eight real-world datasets, we demonstrate that our proposed method outperforms state-of-the-art multi-target feature selection techniques.
On Accurate Discrete-Time Dynamic Models of an Induction Machine
Authors: Herrera Hernández Ramón , Reusser Carlos , Coronel María , Carvajal Rodrigo
Published: January 2024

Induction machines have become the standard for highly demanding industrial applications. This has led to the utilization of modern discrete-time control techniques (such as model predictive control) that require the estimation of internal variables that are not subject to measurement (such as the rotational velocity in sensorless applications). From this point of view, it is fundamental to have accurate discrete-time models of induction machines, particularly given their nonlinear nature, so that control techniques perform according to design requirements. In spite of the above, the modeling of induction machines has not received much attention in the literature, even though more powerful machines and faster microcontrollers are currently being used. To better understand induction machine models for control, in this paper, we develop and compare various discrete-time models of induction machines based on Euler, Taylor, and Runge–Kutta methods. In addition, we compare the Extended Kalman Filter and Unscented Kalman Filter for state estimation in terms of accuracy and computational burden. The models are derived and compared through extensive Monte Carlo simulations and the state estimation techniques are compared in terms of root mean squared error, execution time, and maximum absolute error. Our simulations show that, in general, the Taylor method yields more accurate models than both the Runge–Kutta and Euler methods. In particular, the Taylor method results in a root mean square error that is one order of magnitude smaller than the Euler method for stator current and rotor flux linkages. For rotor angular speed, the Runge–Kutta methods are more accurate than both the Taylor and Euler methods, resulting in a root mean square error that is two orders of magnitude smaller than the Euler method. On the other hand, the Extended Kalman Filter results in smaller execution time than the Unscented Kalman Filter, up to two orders of magnitude. In terms of root mean squared error and maximum absolute error, both filtering algorithms perform similarly.
An Efficient Quadrature Rule for Highly Oscillatory Integrals with Airy Function
Authors: Liu Guidong , Xu Zhenhua , Li Bin
Published: January 2024

In this work, our primary focus is on the numerical computation of highly oscillatory integrals involving the Airy function. Specifically, we address integrals of the form ∫0bxαf(x)Ai(−ωx)dx over a finite or semi-infinite interval, where the integrand exhibits rapid oscillations when ω≫1. The inherent high oscillation and algebraic singularity of the integrand make traditional quadrature rules impractical. In view of this, we strategically partition the interval into two segments: [0,1] and [1,b]. For integrals over the interval [0,1], we introduce a Filon-type method based on a two-point Taylor expansion. In contrast, for integrals over [1,b], we transform the Airy function into the first kind of Bessel function. By applying Cauchy’s integration theorem, the integral is then reformulated into several non-oscillatory and exponentially decaying integrals over [0,+∞), which can be accurately approximated by the generalized Gaussian quadrature rule. The proposed methods are accompanied by rigorous error analyses to establish their reliability. Finally, we present a series of numerical examples that not only validate the theoretical results but also showcase the accuracy and efficacy of the proposed method.
Mitigation of the Collision Risk of a Virtual Impactor Based on the 2011 AG5 Asteroid Using a Kinetic Impactor
Authors: Cinelli Marco
Published: January 2024

In recent years, the escalating risk of natural disasters caused by Near-Earth Objects (NEOs) has garnered heightened scrutiny, particularly in the aftermath of the 2013 Chelyabinsk event. This has prompted increased interest from governmental and supranational entities, leading to the formulation of various measures and strategies aimed at mitigating the potential threat posed by NEOs. This paper delves into the analysis of the 2011 AG5 asteroid within the context of small celestial bodies (e.g., asteroids, comets, or meteoroids) exhibiting resonant orbits with Earth’s heliocentric revolution. Initial observations in 2011 raised alarms regarding the asteroid’s orbital parameters, indicating a significant risk of Earth impact during its resonant encounter in 2040. Subsequent observations, however, mitigated these concerns. Here, we manipulate the orbital elements of the 2011 AG5 asteroid to simulate its behavior as a virtual impactor (a virtual asteroid whose orbit could impact Earth). This modification facilitates the assessment of impact mitigation resulting from a deflection maneuver utilizing a kinetic impactor. The deflection maneuver, characterized as an impulsive change in the asteroid’s momentum, is executed during a resonant encounter occurring approximately two decades before the potential impact date. The paper systematically evaluates the dependence of the deflection maneuver’s efficacy on critical parameters, including the position along the orbit, epoch, and momentum enhancement factor.
Renormalization Group Method for a Stochastic Differential Equation with Multiplicative Fractional White Noise
Authors: Guo Lihong
Published: January 2024

In this paper, we present an application of the renormalization group method developed by Chen, Goldenfeld and Oono for a stochastic differential equation in a space of Hilbert space-valued generalized random variables with multiplicative noise. The driving process is a real-valued fractional white noise with a Hurst parameter greater than 1/2. The stochastic integration is understood in the Wick–Itô–Skorohod sense. This article is a generalization of results of Glatt-Holtz and Ziane, which were for the systems with white noise. We firstly demonstrate the process of formulating the renormalization group equation and the asymptotic solution. Then, we give rigorous proof of the consistency of the approximate solution. In addition, some numerical comparisons are given to illustrate the validity of our results.
Weighted Fejér, Hermite–Hadamard, and Trapezium-Type Inequalities for (h1,h2)–Godunova–Levin Preinvex Function with Applications and Two Open Problems
Authors: Ahmadini Abdullah Ali H. , Afzal Waqar , Abbas Mujahid , Aly Elkhateeb S.
Published: January 2024

This note introduces a new class of preinvexity called (h1,h2)-Godunova-Levin preinvex functions that generalize earlier findings. Based on these notions, we developed Hermite-Hadamard, weighted Fejér, and trapezium type inequalities. Furthermore, we constructed some non-trivial examples in order to verify all the developed results. In addition, we discussed some applications related to the trapezoidal formula, probability density functions, special functions and special means. Lastly, we discussed the importance of order relations and left two open problems for future research. As an additional benefit, we believe that the present work can provide a strong catalyst for enhancing similar existing literature.
Mass Spectrometry Investigation of Some ATP-Binding Cassette (ABC) Proteins
Authors: Agostini Marco , Traldi Pietro , Hamdan Mahmoud
Published: January 2024

Drug resistance remains one of the main causes of poor outcome in cancer therapy. It is also becoming evident that drug resistance to both chemotherapy and to antibiotics is driven by more than one mechanism. So far, there are at least eight recognized mechanisms behind such resistance. In this review, we choose to discuss one of these mechanisms, which is known to be partially driven by a class of transmembrane proteins known as ATP-binding cassette (ABC) transporters. In normal tissues, ABC transporters protect the cells from the toxic effects of xenobiotics, whereas in tumor cells, they reduce the intracellular concentrations of anticancer drugs, which ultimately leads to the emergence of multidrug resistance (MDR). A deeper understanding of the structures and the biology of these proteins is central to current efforts to circumvent resistance to both chemotherapy, targeted therapy, and antibiotics. Understanding the biology and the function of these proteins requires detailed structural and conformational information for this class of membrane proteins. For many years, such structural information has been mainly provided by X-ray crystallography and cryo-electron microscopy. More recently, mass spectrometry-based methods assumed an important role in the area of structural and conformational characterization of this class of proteins. The contribution of this technique to structural biology has been enhanced by its combination with liquid chromatography and ion mobility, as well as more refined labelling protocols and the use of more efficient fragmentation methods, which allow the detection and localization of labile post-translational modifications. In this review, we discuss the contribution of mass spectrometry to efforts to characterize some members of the ATP-binding cassette (ABC) proteins and why such a contribution is relevant to efforts to clarify the link between the overexpression of these proteins and the most widespread mechanism of chemoresistance.
Membrane Separation Technology in Direct Air Capture
Authors: Ignatusha Pavlo , Lin Haiqing , Kapuscinsky Noe , Scoles Ludmila , Ma Weiguo , Patarachao Bussaraporn , Du Naiying
Published: January 2024

Direct air capture (DAC) is an emerging negative CO2 emission technology that aims to introduce a feasible method for CO2 capture from the atmosphere. Unlike carbon capture from point sources, which deals with flue gas at high CO2 concentrations, carbon capture directly from the atmosphere has proved difficult due to the low CO2 concentration in ambient air. Current DAC technologies mainly consider sorbent-based systems; however, membrane technology can be considered a promising DAC approach since it provides several advantages, e.g., lower energy and operational costs, less environmental footprint, and more potential for small-scale ubiquitous installations. Several recent advancements in validating the feasibility of highly permeable gas separation membrane fabrication and system design show that membrane-based direct air capture (m-DAC) could be a complementary approach to sorbent-based DAC, e.g., as part of a hybrid system design that incorporates other DAC technologies (e.g., solvent or sorbent-based DAC). In this article, the ongoing research and DAC application attempts via membrane separation have been reviewed. The reported membrane materials that could potentially be used for m-DAC are summarized. In addition, the future direction of m-DAC development is discussed, which could provide perspective and encourage new researchers’ further work in the field of m-DAC.
Development of a New Affinity Gold Polymer Membrane with Immobilized Protein A
Authors: Steegmüller Tobias , Kratky Tim , Gollwitzer Lena , Schwaminger Sebastian Patrick , Berensmeier Sonja
Published: January 2024

New and highly selective stationary phases for affinity membrane chromatography have the potential to significantly enhance the efficiency and specificity of therapeutic protein purification by reduced mass transfer limitations. This work developed and compared different immobilization strategies for recombinant Protein A ligands to a gold-sputtered polymer membrane for antibody separation in terms of functionalization and immobilization success, protein load, and stability. Successful, functionalization was validated via X-ray photoelectron spectroscopy (XPS). Here, a recombinant Protein A ligand was coupled by N-hydroxysuccinimide (NHS)/N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) chemistry to carboxy-functionalized, gold-sputtered membranes. We achieved a binding capacity of up to 104 ± 17 mg of the protein ligand per gram of the gold-sputtered membrane. The developed membranes were able to successfully capture and release the monoclonal antibody (mAb) Trastuzumab, as well as antibodies from fresh frozen human blood plasma in both static and dynamic setups. Therefore, they demonstrated successful functionalization and immobilization strategies. The antibody load was tested using bicinchoninic acid (BCA), ultraviolet-visible spectroscopy (UV-vis) measurements, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The outcome is a fully functional affinity membrane that can be implemented in a variety of different antibody purification processes, eliminating the need for creating individualized strategies for modifying the surface to suit different substrates or conditions.
Durability of Single Lap Friction Stir Welded Joints between S355-J0 Steel and AA5083 Aluminum Alloy–Mechanical Tests
Authors: Chiara Borsellino , Favaloro Federica , Di Bella Guido
Published: January 2024

This study aims to investigate a friction stir welded joint between steel and aluminum alloy. FSW is nowadays one of the most interesting joining techniques due to the possibility of connecting materials and thicknesses that are difficult or impossible to weld with traditional techniques. The main advantage is that materials are not affected by thermal cycle problems during solidification and cooling, and the absence of fumes and pollution during the process favors the quality of the welded joint. The life of metal joints could be greatly reduced in a corrosive environment since the less noble material will tend to increase its corrosion rate, while the nobler one will reduce its electrochemical dissolution. Accelerated aging tests (i.e., salt fog test) are used to estimate the lifetime of metal joints in highly aggressive environments. The aim of the present work is to evaluate the durability at a long aging time in the salt spray test (according to ASTM B117) of carbon steel/aluminum alloy joints, obtained by FSW. In this first part, mechanical test results are reported. A deep metallographic and chemical investigation is going to be reported in part two. The current research work investigates the welding direction and residence time in the salt spray chamber. The breakage of all tested samples, evaluated after the tensile tests were carried out, always occurs at the interface of the joint, regardless of the change of direction of the weld on the advancing or retreating side. The welding direction influences the breakage of the joint only before the aging treatment. Specifically, specimens produced in advance are characterized by increased joint strength. On the other hand, the factor that influences the performance of the joints is the exposure time where, starting from the first point of aging, i.e., after two months, there is a decrease in the maximum load of 40%, and the effect of corrosion leads to a significant deterioration of the weld which remains almost similar until the last point of aging.
Irradiation Hardening and Microstructure Study of MAX-Phase-Dispersion-Strengthened Vanadium Alloy under Self-Ion Irradiation
Authors: Zhao Yinshu , Zheng Pengfei , Wei Yaxia , Luo Hongtai , Qian Wei , Zhang Guihang , Li Feng , Zhang Ming , Zhang Pengbo
Published: January 2024

V-4Cr-4Ti alloy is one of the candidate structural materials for future fusion reactors due to its desirable characteristics. In our previous research, MAX-phase-dispersion-strengthened vanadium alloy (V-4Cr-4Ti-1.5Y-0.3Ti3SiC2), prepared through mechanical alloying, showed excellent thermal stability and creep resistance and was expected to have good radiation resistance. This study investigates the effects of 2.5 MeV V2+ ion irradiation on V-4Cr-4Ti-1.5Y-0.3Ti3SiC2 and V-4Cr-4Ti alloys at 500 °C, with peak damage of 0.8, 3.5, and 6.1 dpa. Transmission electron microscopy and nanoindentation were used to examine the changes in microstructure and hardness before and after irradiation. The microscopic analysis reveals that dispersed nanoparticles maintained good stability under irradiation. Defect clusters grow with increasing irradiation doses in both materials. The nanoindentation results show that V-4Cr-4Ti-1.5Y-0.3Ti3SiC2 has higher initial hardness and lower irradiation hardening, indicating better resistance to radiation hardening than V-4Cr-4Ti. This research serves as a valuable reference for the assessment of the irradiation resistance of Ti3SiC2-dispersion-strengthened V-4Cr-4Ti alloy.
High-Temperature Mechanical Properties and Microstructure of Ultrathin 3003mod Aluminum Alloy Fins
Authors: Zheng Wenhui , Ni Chengyuan , Xia Chengdong , Deng Shaohui , Jiang Xiaoying , Xu Wei
Published: January 2024

The effects of Si, Fe and Zr elements on the high temperature properties and microstructure of ultrathin 3003mod aluminum alloy fins were studied by means of high-temperature tensile tests, sagging tests and microstructure analyses. The results show that the alloying of Si, Fe, and Zr elements formed a large amount of nano-scale α-Al(Mn,Fe) Si and Al3Zr particles, and significantly reduced the number of micro-scale coarse Al6(Mn,Fe) particles in the 3003mod aluminum alloy, exhibiting 5 to 10 MPa higher strength and better sagging resistance than 3003 aluminum alloy at the same temperature. The variations in properties such as high-temperature mechanical properties, sagging resistance and elongation below 400 °C were ascribed to the high-stability nanoparticles effectively preventing recovery and grain boundary migration, as well as reducing the nucleation cores of recrystallization. The nanoparticles in 3003mod aluminum alloy were coarsened significantly at 500 °C, and the grains were completely recrystallized and coarsened, resulted in a significant decrease in strength, sagging resistance and elongation compared with these at 400 °C.
A Review of the Ethnobotanical Use, Chemistry and Pharmacological Activities of Constituents Derived from the Plant Genus Geijera (Rutaceae)
Authors: Dugan Deepika , Bell Rachael J. , Brkljača Robert , Rix Colin , Urban Sylvia
Published: January 2024

Geijera Schott is a plant genus of the Rutaceae Juss. (rue and citrus) family, comprising six species which are all native to Oceania. Of the plants belonging to this genus, the most significant species that has a customary use is Geijera parviflora, which was used by Indigenous Australians, primarily as a pain reliever. Herein, a comprehensive review of the literature published on the genus Geijera from 1930 to 2023 was conducted. This is the first review for this plant genus, and it highlights the chemical constituents reported to date, together with the range of pharmacological properties described from the various species and different parts of the plant. These properties include anti-inflammatory, anti-microbial, anti-parasitic, insect repellent, analgesic, neuroactive, and anti-cancer activities. Finally, a reflection on some of the important areas for future focused studies of this plant genus is provided.
Physiological Perturbations in Combat Sports: Weight Cycling and Metabolic Function—A Narrative Review
Authors: Lebron Modesto A. , Stout Jeffrey R. , Fukuda David H.
Published: January 2024

Combat sports athletes seeking a competitive edge often engage in weight management practices to become larger than their opponents, which ultimately includes periods of gradual weight loss, rapid weight loss, and weight regain. This pattern of weight loss and regain is known as weight cycling and often includes periods of low energy availability, making combat sports athletes susceptible to metabolic dysfunction. This narrative review represents an effort to explore the metabolic perturbations associated with weight cycling and outline the short-, medium-, and long-term effects on metabolic flexibility, function, and health. The short-term effects of rapid weight loss, such as a reduced metabolic rate and alterations to insulin and leptin levels, may prelude the more pronounced metabolic disturbances that occur during weight regain, such as insulin resistance. Although definitive support is not currently available, this cycle of weight loss and regain and associated metabolic changes may contribute to metabolic syndrome or other metabolic dysfunctions over time.
Jet Electrochemical Micromilling of Ti-6Al-4V Using NaCl–Ethylene Glycol Electrolyte
Authors: Niu Shen , Huang Kaiqiang , Ming Pingmei , Wang Siru , Zhao Fei , Qin Ge , Liu Huan
Published: January 2024

Titanium alloys are widely used in aerospace and biomedicine because of their excellent mechanical characteristics, but these properties also make such alloys difficult to cut. Jet electrochemical micromilling (JEMM) is based on the principle of electrochemical anodic dissolution; it has some inherent advantages for the machining of titanium alloy microstructures. However, titanium oxidizes readily, forming an oxide film that impedes a uniform dissolution during electrochemical machining. Therefore, a high voltage and an aqueous NaCl electrolyte are usually used to break the oxide film, which can lead to severe stray corrosion. To overcome this problem, the present study investigated the JEMM of Ti-6Al-4V using a NaCl–ethylene glycol (NaCl-EG) electrolyte. Electrochemical testing showed that Ti-6Al-4V exhibits a better corrosion resistance in the NaCl-EG electrolyte compared to the aqueous NaCl electrolyte, thereby reducing stray corrosion. The localization and surface quality of the grooves were enhanced significantly when using JEMM with a NaCl-EG electrolyte. A multiple-pass strategy was adopted during JEMM to improve the aspect ratio, and the effects of the feed depth and number of passes on the multiple-pass machining performance were investigated. Ultimately, a square annular microstructure with a high geometric dimensional consistency and a smooth surface was obtained via JEMM with multiple passes using the optimal parameters.
A Large-Range and High-Sensitivity Fiber-Optic Fabry–Perot Pressure Sensor Based on a Membrane-Hole-Base Structure
Authors: Duan Bowen , Hai Zhenyin , Guo Maocheng , Zheng Yongqiu , Chen Jiamin , Bai Jiandong , Su Zhixuan , Liang Rui , Zhu Hongtian , Zhang Qi , Xue Chenyang
Published: January 2024

In the field of in situ measurement of high-temperature pressure, fiber-optic Fabry–Perot pressure sensors have been extensively studied and applied in recent years thanks to their compact size and excellent anti-interference and anti-shock capabilities. However, such sensors have high technological difficulty, limited pressure measurement range, and low sensitivity. This paper proposes a fiber-optic Fabry–Perot pressure sensor based on a membrane-hole-base structure. The sensitive core was fabricated by laser cutting technology and direct bonding technology of three-layer sapphire and develops a supporting large-cavity-length demodulation algorithm for the sensor’s Fabry–Perot cavity. The sensor exhibits enhanced sensitivity, a simplified structure, convenient preparation procedures, as well as improved pressure resistance and anti-harsh environment capabilities, and has large-range pressure sensing capability of 0–10 MPa in the temperature range of 20–370 °C. The sensor sensitivity is 918.9 nm/MPa, the temperature coefficient is 0.0695 nm/(MPa∙°C), and the error over the full temperature range is better than 2.312%.