bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of EGCG–Methacrylate-Functionalized Resin Infiltrant on White Spot Lesions: An In Vitro Study
Authors: Landmayer Karin , Iatarola Bruna de Oliveira , Pereira Talita Portela , Mori Raquel Shimizu , Obeid Alyssa Teixeira , Vertuan Mariele , Chrisostomo Daniela Alvim , Magalhães Ana Carolina , Alreshaid Lulwah , dos Santos Paulo Henrique , Prakki Anuradha , Francisconi-dos-Rios Luciana Fávaro
Published: December 2024

This study evaluated the color change (ΔE00) and penetration depth (PD) of white spot lesions (WSLs) infiltrated with the resin infiltrant (Icon®) functionalized with methacrylate epigallocatechin-3-gallate (EGCG). To introduce polymerizable double bonds, EGCG was reacted with methacryloyl chloride (EM). Subsequently, the Icon resin infiltrant (I) was loaded with neat EGCG (IE) or EGCG–methacrylate (IEM) at 2 wt% each. WSLs were created on bovine enamel blocks and treated with I, IE, or IEM. Sound and untreated enamel surfaces were used as controls (C). Infiltrant PD (%) was determined by Confocal Laser Scanning Microscopy (CLSM, n = 12) analysis. For color change (ΔE00) determination (n = 14), ΔL, Δa, and Δb, half of each sample was kept sound as a reference area. The color was determined with a spectrophotometer. Data were statistically evaluated (p = 0.05). Surface morphology was obtained as a qualitative response variable using 3D CLSM. PD (%) did not differ statistically for I, IE, and IEM (p = 0.780). Groups I and IEM showed similar performance on color change (ΔE00) compared to the control group, while IE exhibited intermediate results, with no significant difference observed between the untreated, I, and IEM groups (p < 0.001). IEM promoted the masking of the WSL color without interfering with the PD.
Assessing the Logistics Efficiency of Baltic Region Seaports Through DEA-BCC and Spatial Analysis
Authors: Locaitienė Vilma , Čižiūnienė Kristina
Published: December 2024

Efficient logistics is a key factor in the competitiveness of seaports, especially in regions such as the Baltic Sea, where ports play important roles as hubs in the European Union’s Trans-European transport network (TEN-T). However, there are a lack of comprehensive studies focusing on the logistics efficiency of Baltic Sea ports, especially those integrating technical and technological factors. This study aimed to assess changes in the logistics efficiency of 15 major ports in the Baltic Sea region between 2019 and 2023, taking into account the technological and infrastructure-related elements that influence port performance. The model developed by the authors integrates the nearest neighbour method for cluster identification, data envelopment analysis using the Banker, Charnes, and Cooper (DEA-BCC) model to assess the overall technical, pure technical, and scale logistics efficiency, and spatial autocorrelation analysis to explore spatial interactions. For the DEA-BCC model, constraints were defined for each port based on inputs (number and length of berths) and outputs (cargo and container volumes for 2019–2023). The spatial autocorrelation analysis examined the relationships among the Baltic Sea ports, container volumes, and logistic efficiency values derived from the DEA model. Recognizing the sensitivity of the weight matrix in previous studies, this paper introduced an enhanced two-factor weighting matrix that incorporated geographical distance and the port connectivity index, calculated by the United Nations Conference on Trade and Development (UNCTAD). The statistical reliability of the results was validated using z-scores and p-values. The results showed that the overall technical efficiency of the ports analysed during the period considered was 47.2%, the pure technical efficiency was 61.0%, and the average scale efficiency was around 76%, indicating that diminishing returns to scale dominated. The spatial analysis showed a strong correlation between port connectivity and efficiency, indicating that well-connected ports, such as Gdańsk and Gdynia, had a higher efficiency. The findings make a significant contribution to the understanding of the logistics efficiency of Baltic Sea ports and highlights the importance of regional cooperation, infrastructure improvements, and better connectivity strategies to improve the overall efficiency of seaports in the region.
Effects of Drying Treatments on the Physicochemical Characteristics and Antioxidant Properties of the Edible Wild Mushroom Cyttaria espinosae Lloyd (Digüeñe Mushroom)
Authors: Villalobos-Pezos Marcelo , Muñoz Fariña Ociel , Ah-Hen Kong Shun , Garrido Figueroa María-Fernanda , García Figueroa Olga , González Esparza Alexandra , González Pérez de Medina Luisbel , Bastías Montes José Miguel
Published: December 2024

The wild mushroom Cyttaria espinosae, also known as digüeñe, is a parasitic ascomycete of Nothofagus trees endemic to southern Chile. This species of wild mushroom is of great nutritional importance, especially for the Mapuche indigenous communities, and is highly sought after. Edible wild mushrooms, rich in bioactive compounds, are a potential source of health-promoting components. In the case of C. espinosae, research on its bioactive compounds is still lacking as is research, on the effect of preservation treatments on these compounds due to its perishability. This study evaluates the effects of three drying treatments; freeze-drying, hot-air drying, and microwave–vacuum drying. The rehydration capacity, color, and microstructural properties of dried mushrooms were evaluated using SEM, while, total phenolic content, antioxidant activity determined by DPPH and ORAC assays, and ergothioneine levels were investigated in both fresh and dried extracts of C. espinosae. The results showed that freeze-drying and microwave–vacuum drying are recommended treatments for the digüeñe mushroom due to superior outcomes in rehydration rate, color, and structural properties observed through SEM images. Total phenolic content and antioxidant activity were higher in mushroom extracts dried by microwave–vacuum compared to the other drying treatments.
Omics-Based Comparison of Fungal Virulence Genes, Biosynthetic Gene Clusters, and Small Molecules in Penicillium expansum and Penicillium chrysogenum
Authors: Bartholomew Holly P. , Gottschalk Christopher , Cooper Bret , Bukowski Michael R. , Yang Ronghui , Gaskins Verneta L. , Luciano-Rosario Dianiris , Fonseca Jorge M. , Jurick Wayne M.
Published: December 2024

Penicillium expansum is a ubiquitous pathogenic fungus that causes blue mold decay of apple fruit postharvest, and another member of the genus, Penicillium chrysogenum, is a well-studied saprophyte valued for antibiotic and small molecule production. While these two fungi have been investigated individually, a recent discovery revealed that P. chrysogenum can block P. expansum-mediated decay of apple fruit. To shed light on this observation, we conducted a comparative genomic, transcriptomic, and metabolomic study of two P. chrysogenum (404 and 413) and two P. expansum (Pe21 and R19) isolates. Global transcriptional and metabolomic outputs were disparate between the species, nearly identical for P. chrysogenum isolates, and different between P. expansum isolates. Further, the two P. chrysogenum genomes revealed secondary metabolite gene clusters that varied widely from P. expansum. This included the absence of an intact patulin gene cluster in P. chrysogenum, which corroborates the metabolomic data regarding its inability to produce patulin. Additionally, a core subset of P. expansum virulence gene homologues were identified in P. chrysogenum and were similarly transcriptionally regulated in vitro. Molecules with varying biological activities, and phytohormone-like compounds were detected for the first time in P. expansum while antibiotics like penicillin G and other biologically active molecules were discovered in P. chrysogenum culture supernatants. Our findings provide a solid omics-based foundation of small molecule production in these two fungal species with implications in postharvest context and expand the current knowledge of the Penicillium-derived chemical repertoire for broader fundamental and practical applications.
The Role of Rotational Thromboelastometry in Early Detection of the Hemostatic Derangements in Neonates with Systemic Candida Infection
Authors: Sokou Rozeta , Palioura Alexia Eleftheria , Konstantinidi Aikaterini , Lianou Alexandra , Lampridou Maria , Theodoraki Martha , Piovani Daniele , Bonovas Stefanos , Tsante Konstantina A. , Ioannou Petros , Iacovidou Nicoletta , Tsantes Andreas G.
Published: December 2024

Background: Systemic Candida infection (SCI) is the third most common cause of late-onset sepsis in Neonatal Intensive Care Units (NICU). While platelet involvement in fungal infections has been extensively studied, evaluation of the hemostatic mechanism in Candida infections, especially in neonates, has not been widely investigated. The aim of the current study was to evaluate the hemostatic profile of neonates with SCI through rotational thromboelastometry (ROTEM), a laboratory method that assesses the viscoelastic properties of blood. Methods: This is a single-centered prospective cohort study including a group of neonates with SCI (n = 21); the control group consisted of healthy neonates (n = 24). Demographics, clinical parameters, and laboratory data were recorded at the disease onset. Neonatal scores for the assessment of disease severity (Modified NEOMOD, nSOFA, and NeoBAT) were also calculated. ROTEM parameters of neonates with SCI were compared to those of healthy neonates. Results: ROTEM parameters differed between neonates with SCI and healthy neonates, indicating a hypocoagulable profile of infected neonates. Specifically, neonates with SCI had significantly prolonged clotting time (CT) and clot formation time (CFT), as well as lower clot amplitude at 10 min (A10) and maximum clot firmness (MCF) when compared to healthy neonates (p values < 0.05), findings that remained consistent after adjusting for confounding factors such as gestational age, birth weight, and sex. In addition, a strong correlation was noted between ROTEM parameters and disease severity based on the modified NEOMOD, nSOFA, and NeoBAT scores. Conclusions: ROTEM parameters revealed a hypocoagulable profile in neonates during the early stages of SCI, which is also associated with disease severity. The results of this study highlight the need for monitoring of hemostatic status of this vulnerable group of patients and indicate that ROTEM analysis may have a role in the early detection of the hemostatic derangements associated with SCI in neonates, in order to ensure timely diagnosis and targeted therapeutic intervention.
Stress-Driven Production of γ-Aminobutyric Acid Using Non-Conventional Yeast Strains Kluyveromyces marxianus JMY140K and Metschnikowia reukaufii JMY075
Authors: Fan Ting-Ting , Chen Chao , Zeng Du-Wen , Wang Feng-Lou , Xu Zhao-Xian , Jin Ming-Jie , Zou Yue , Li Jun , Zhao Xin-Qing
Published: December 2024

γ-Aminobutyric acid (GABA) is a valuable amino acid widely used in food, healthcare, and agriculture. GABA bioproduction by budding yeasts has been commonly reported, but related studies using non-conventional yeasts remain limited. In this study, two non-conventional natural yeast strains, namely, Kluyveromyces marxianus JMY140K and Metschnikowia reukaufii JMY075, were identified as promising GABA producers, and M. reukaufii JMY075 was discovered to be a GABA producer. Enhanced GABA production was observed in the two yeast strains under stress conditions, including high temperature and high ethanol and acetic acid levels. In particular, K. marxianus JMY140K showed 7.93 times higher GABA titers under thermal stress than that of the control. External stress conditions significantly influenced the GABA production of these two yeast strains. The culture filtrate of K. marxianus JMY140K also showed promising activities in human skin cells. In addition, K. marxianus JMY140K could also produce GABA using rice straw hydrolysate, which indicated that it has the potential to produce GABA using renewable biomass. Our studies provide insight for further enhancing the GABA production of natural yeasts and promoting its biotechnology applications.
Beyond the Traditional VIX: A Novel Approach to Identifying Uncertainty Shocks in Financial Markets
Authors: Jha Ayush , Shirvani Abootaleb , Rachev Svetlozar T. , Fabozzi Frank J.
Published: December 2024

We introduce a new identification strategy for uncertainty shocks to explain macroeconomic volatility in financial markets. The Chicago Board Options Exchange Volatility Index (VIX) measures the market expectations of future volatility, but traditional methods based on second-moment shocks and the time-varying volatility of the VIX often do not effectively to capture the non-Gaussian, heavy-tailed nature of asset returns. To address this, we constructed a revised VIX by fitting a double-subordinated Normal Inverse Gaussian Lévy process to S&P 500 log returns, to provide a more comprehensive measure of volatility that captures the extreme movements and heavy tails observed in financial data. Using an axiomatic framework, we developed a family of risk–reward ratios that, when computed with our revised VIX and fitted to a long-memory time series model, provide a more precise identification of uncertainty shocks in financial markets.
Innovative Fly-Ash-Based Soil Crust Rehabilitation: Enhancing Wind Erosion Resistance in Gravel-Layered Desert Mining Areas
Authors: Zheng Yu , Guan Weiming , Li Jingwen , Hu Zhenqi , Li Gensheng , Xie Meng , Zhang Xuewei
Published: December 2024

Gravel layers are vital ecological barriers in Gobi Desert mining areas. However, open-pit activities increase wind and soil erosion. Thus, the effects of fly ash addition, water content, and compaction on the shear strength and wind erosion resistance of soil crusts were explored by compaction tests, direct shear tests, and wind tunnel experiments. (1) The results of the direct shear test and vane shear test show that the modified soil sample achieved the maximum shear strength under the conditions of 15% fly ash content, 13% water content, and 3 compaction cycles. (2) The results of the wind tunnel test indicate that the wind erosion resistance of the gravel layer soil crust was improved after fly ash treatment. Compared to the untreated soil crust, the wind erosion amount of the treated soil was reduced by 23%. (3) Microscopic analysis revealed that hydration products from fly ash filled the soil pores, enhancing particle bonding and soil structure, using a scanning electron microscope (SEM) and an X-ray fluorescence spectrometer (XRF). (4) Considering the water scarcity in the Eastern Junggar Coalfield of China, a revised rehabilitation scheme was selected, involving 11% water content and single compaction, offering a balance between performance and economic efficiency. This study provides a novel approach to gravel layer restoration in arid mining regions using fly ash as a soil stabilizer, offering a sustainable method to enhance wind erosion resistance and promote fly ash recycling.
Analysis of Slow-Released Fertilisers as a Source of Microplastics
Authors: Isakov Vladimir , Vlasova Elena , Forer Vladislav , Kenny Jose , Lyulin Sergey
Published: December 2024

One of the main strategies for improving the efficiency of agricultural production is the use of fertilisers with slow or controlled release of nutrients, in which the granules of mineral fertilisers are covered with polymeric shells. The composition of the polymer coatings of mineral fertiliser granules with slow or controlled release of two widespread manufacturers and their ability to adsorb some heavy metal ions on their surface were examined in this study. It was found that the base polymers used to encapsulate the fertilisers studied are the co-polymer polyethylene–polyacrylic acid in the Brand A, and polyacrylamide, polyacrylic acid, and its esters in the Brand B fertiliser coating. The maximum adsorption rate of heavy metal ions on the surface of the polymer coatings with the rest of the mineral filler of Brand A and Brand B fertilisers was 54.64 and 28.90 mg/g for Cd(II) ions, 30.77 and 14.03 mg/g for Pb(II) ions, respectively. Therefore, the solution to the problem of increasing the efficiency of agricultural production through the use of fertilisers with slow or controlled release of nutrients leads to environmental pollution by microplastics remaining in the soil after fertiliser application, which are also capable of adsorbing from the soil various toxic pollutants.
Drivers and Dynamics of Forest and Grassland Ecosystems in the Altai Mountains: A Framework for National Park Conservation
Authors: Deng Menghan , Hu Faxiang , Ma Wanli , Yang Wenchao , Luan Xiaofeng
Published: December 2024

The Altai Mountains region, characterized by its unique biodiversity and significant ecological value, is increasingly under pressure from anthropogenic activities and climate change. This study investigates the spatial and temporal dynamics of forest and grassland ecosystems in the Altai Mountains National Park Candidate Area from 2000 to 2020, and proposes a comprehensive framework for the conservation and management of national parks. Through a detailed analysis of land cover changes, we observed significant forest expansion of 13.65% and grassland degradation of 11.69%. Rapid forest expansion occurred before 2010, followed by accelerated grassland degradation after that, with 2010 identified as the critical turning point. Our analysis highlights the role of key drivers, such as soil type, elevation, cropland expansion, and human activities, in shaping these ecosystems. Using Geodetector and propensity score matching methods, we evaluated the effectiveness of existing protected areas in mitigating forest and grassland loss. While protected areas effectively contributed to forest restoration, they were less successful in preventing grassland decline, underscoring the need for integrated management approaches. The findings from this study provide critical insights into ecosystem dynamics and conservation effectiveness, offering valuable guidance for the establishment of national-park-type protected areas and broader regional conservation efforts.
Unveiling Differentiation Characteristics of Vegetation Restoration Potential for Browning Areas in China’s Hilly and Gully Region
Authors: He Juan , Zhou Wei , Qian Mingjie , Zha Enmao , Cao An , Shi Xueyi
Published: December 2024

Vegetation greening resulting from ecological engineering efforts has statistically contributed to environmental improvement, through enhancing ecosystem effectiveness remains a challenge. Nevertheless, there has been a notable lack of research dedicated to enhancing vegetation resilience and restoration potential by mitigating vegetation browning in watersheds within arid and semi-arid regions. This study fills that gap by identifying the spatial heterogeneity in ecological resilience using statistical analyses and an exponential decay approach. It then evaluates the potential for ecological restoration by optimizing ecosystem structures in browning areas based on resilience and reference state. The key findings included the following: (1) With a narrower interquartile range, kNDVI values from 2015 to 2023 demonstrated notable increases as compared to 2000–2014. The northern and eastern sub-watersheds showed greater vegetation restoration, but the southern regions showed less resilience. (2) Vegetation resilience in the majority of sub-watersheds was concentrated at moderate levels, and the number of grids with strong positive tendencies decreased, according to the analysis of grid trends. (3) Fifteen reference states were established for browning areas based on the current natural conditions. The larger restoration potential ratio showed notable differences in sub-watershed restoration, indicating opportunities for improvement. Extreme vegetation degradation demonstrated little potential for restoration in resource-poor areas. This study provides valuable insights into integrating resilience and restoration potential into ecological restoration practices, advancing the application of ecological engineering strategies.
The Importance of Automatic Counters for Sustainable Management in Rural Areas: The Case of Hiking Trails in Historic Villages of Portugal
Authors: Luque Ana , Alves Luiz
Published: December 2024

The dynamics of territorial planning, the management of its tourism products, and the monitoring of demand flows and their impact on the territorial structure (social, economic and environmental) require tools that support the acquisition of reliable quantitative data, as far as possible in real time, that are easy to manage and allow immediate analysis. In the case of structures and equipment anchored in the nature tourism segment, in particular hiking trails, in addition to determining the demand indices in a network of hiking trails and understanding their territorial and temporal dynamics, the data collected through automatic counters is a crucial tool to support territorial management and evaluate the patterns and flows of tourist demand. Based on these assumptions, this research seeks to analyse demand data observed on eleven hiking trails in the Historic Villages of Portugal, collected through automatic monitoring systems (counters). In four years, between 2020 and 2023, the trails analysed generated a demand of almost 190,000 passages, which translates into an annual average of 47,500 passages in the tourism product “Historic Villages of Portugal” (more than 4800 passages for each trail), mostly in the spring and autumn months, mainly on weekends.
Cryptocurrencies as a Threat to U.S. Homeland Security Interests
Authors: Givens Austen D.
Published: December 2024

The use of cryptocurrencies in transnational criminal activities has grown in recent years. The scholarly literature on cryptocurrencies recognizes this trend. Yet, there has been comparatively little attention paid to the degree to which cryptocurrencies pose a direct threat to U.S. homeland security interests. This article fills a gap in the scholarly literature on cryptocurrencies by presenting evidence that cryptocurrencies are a threat to U.S. homeland security interests, specifically because of their uses for financing terrorism, enabling human and drug trafficking, and evading international financial sanctions.
Interphase Influence on the Effective Thermal Conductivity Coefficients of Fiber Composites
Authors: Turant Jan
Published: December 2024

This study proposes a two-scale approach to determining the effective thermal conductivity of fibrous composite materials. The analysis was first carried out at the fiber–interphase level to calculate the effective thermal conductivity of this system, and next at the whole composite structure level. At both scales, the system behavior was analyzed using the finite element method. To determine the effective thermal conductivity for the fiber–interphase system, an inverse problem was solved, while a simple unidirectional heat conduction test was performed for the entire composite. The simulations were carried out for typical fibrous composites: carbon fibers–epoxy resin and glass fibers–epoxy resin. The results showed a significant impact of realistically observed interphase thicknesses on the heat conduction properties of the tested composites.
Advanced Bending and Forming Technologies for Bimetallic Composite Pipes
Authors: Li Hui , Zhu Yingxia , Chen Wei , Yuan Chen , Wang Lei
Published: December 2024

Bimetallic composite pipes, as critical components, effectively integrate the superior properties of diverse materials to meet the growing demand for lightweight, high-strength, and corrosion-resistant solutions. These pipes find extensive applications in petrochemical, power generation, marine engineering, refrigeration equipment, and automotive manufacturing industries. This paper comprehensively reviews advanced bending and forming technologies, with a focus on challenges such as wrinkling, excessive wall thinning, springback, cross-sectional distortion, and interlayer separation. The review combines theoretical analysis, experimental findings, and numerical simulations to provide insights into defect prevention strategies and process optimization. It also evaluates emerging technologies such as artificial neural networks and intelligent control systems, which demonstrate significant potential in enhancing bending accuracy, reducing defects, and improving manufacturing efficiency. Additionally, this work outlines future research directions, emphasizing innovations required to meet the stringent performance standards of bimetallic composite pipe components in high-end applications.
The Influence of Process Parameters on Hydrogen-Terminated Diamond and the Enhancement of Carrier Mobility
Authors: Chen Xingqiao , Yang Mingyang , Mu Yuanyuan , Yang Chengye , Jia Zhenglin , Liu Chaoping , Li He , Jiang Nan , Nishimura Kazuhito , Guo Liangchao , Chee Kuan W. A. , Yuan Qilong , Li Xiaocheng , Song Hui
Published: December 2024

With the development of diamond technology, its application in the field of electronics has become a new research hotspot. Hydrogen-terminated diamond has the electrical properties of P-type conduction due to the formation of two-dimensional hole gas (2DHG) on its surface. However, due to various scattering mechanisms on the surface, its carrier mobility is limited to 50–200 cm2/(Vs). In this paper, the effects of process parameters (temperature, CH4 concentration, time) on the electrical properties of hydrogen-terminated diamond were studied by microwave plasma chemical vapor deposition (CVD) technology, and hydrogen-terminated diamond with a high carrier mobility was obtained. The results show that homoepitaxial growth of a diamond film on a diamond substrate can improve the carrier mobility. Hydrogen-terminated diamond with a high carrier mobility and low sheet resistance can be obtained by homoepitaxial growth of a high-quality diamond film on a diamond substrate with 4% CH4 concentration and hydrogen plasma treatment at 900 ℃ for 30 min. When the carrier concentration is 2.03 × 1012/cm2, the carrier mobility is 395 cm2/(Vs), and the sheet resistance is 7.82 kΩ/square, which greatly improves the electrical properties of hydrogen-terminated diamond. It can enhance the transmission characteristics of carriers in the conductive channel, and is expected to become a potential material for application in devices, providing a material choice for its application in the field of semiconductor devices.
Properties, Advantages, and Prospects of Using Cobalt-Free Composites Based on Tungsten Carbide in Industry
Authors: Kurbanbekov Sherzod , Kozhakhmetov Yernat , Skakov Mazhyn , Seitov Bekbolat , Aidarova Madina , Tabiyeva Yerkezhan
Published: December 2024

This paper reviews recent advances in the synthesis of cobalt-free high-strength tungsten carbide (WC) composites as sustainable alternatives to conventional WC-Co composites. Due to the high cost of cobalt, limited supply, and environmental concerns, researchers are exploring nickel, iron, ceramic binders, and nanocomposites to obtain similar or superior mechanical properties. Various synthesis methods such as powder metallurgy, encapsulation, 3D printing, and spark plasma sintering (SPS) are discussed, with SPS standing out for its effectiveness in densifying and preventing WC grain growth. The results show that cobalt-free composites exhibit high strength, wear and corrosion resistance, and harsh environment stability, making them viable competitors for WC-Co materials. The use of nickel and iron with SPS is shown to enable the development of environmentally friendly, cost-effective materials. It is emphasized that microstructural control and phase management during sintering are critical to improve a material’s properties. The application potential of these composites covers mechanical engineering, metallurgy, oil and gas, and aerospace, emphasizing their broad industrial relevance.
Effects of Doping on Elastic Strain in Crystalline Ge-Sb-Te
Authors: Cho Ju-Young , Lee So-Yeon
Published: December 2024

Phase-change random access memory (PcRAM) faces significant challenges due to the inherent instability of amorphous Ge2Sb2Te5 (GST). While doping has emerged as an effective method for amorphous stabilization, understanding the precise mechanisms of structural modification and their impact on material stability remains a critical challenge. This study provides a comprehensive investigation of elastic strain and stress in crystalline lattices induced by various dopants (C, N, and Al) through systematic measurements of film thickness changes during crystallization. Through detailed analysis of cross-sectional electron microscopy data and theoretical calculations, we reveal distinct behavior patterns between interstitial and substitutional dopants. Interstitial dopants (C and N) generate substantial elastic strain energy (~9 J/g) due to their smaller atomic radii (0.07–0.08 nm) and ability to occupy spaces between lattice sites. In contrast, substitutional dopants (Al) produce lower strain energy (~5 J/g) due to their similar atomic radius (0.14 nm) to host atoms. We demonstrate that N doping achieves higher elastic strain energy compared to C doping, attributed to its preferential formation of Ge-N bonds and resulting lattice distortions. The correlation between dopant properties, structural features, and induced strain energy provides quantitative insights for optimizing dopant selection. These findings establish a fundamental framework for understanding dopant-induced thermodynamic stabilization in GST materials, offering practical guidelines for enhancing the reliability and performance of next-generation PcRAM devices.
Topology-Aware Efficient Path Planning in Dynamic Environments
Authors: Zhao Haoning , Guo Jiamin , Wang Chaoqun , Rong Xuewen , Li Yibin
Published: December 2024

This study presents a path-planning approach toward efficient obstacle avoidance in dynamic environments. The developed approach features the awareness of the topological structure of the dynamic environment at a planning instant. It is achieved by employing a homology class path planner to generate a set of non-homotopy global paths. The global paths are cast into tree structures separately and optimized by the developed sampling-based path-planning methods. This mechanism can adaptively adjust the optimizing step size according to the change in the dynamic environment, and the sampling module uses the Gaussian Mixture Model (GMM) Optimizer to control the sampling space. The approach seeks the globally optimal path as it maintains and optimizes homology classes of admissible candidate paths of distinctive topologies in parallel. We conduct various experiments in dynamic environments to verify the developed method’s effectiveness and efficiency. It is demonstrated that the developed method can perform better than the state of the art.
Computational Fluid Dynamics Simulation and Analysis of Non-Newtonian Drilling Fluid Flow and Cuttings Transport in an Eccentric Annulus
Authors: Ahsan Muhammad , Fahad Shah , Butt Muhammad Shoaib
Published: December 2024

This study examines the flow behavior as well as the cuttings transport of non-Newtonian drilling fluid in the geometry of an eccentric annulus, accounting for what impacts drill pipe rotation might have on fluid velocity, as well as annular eccentricity on axial and tangential distributions of velocity. A two-phase Eulerian–Eulerian model was developed by using computational fluid dynamics to simulate drilling fluid flow and cuttings transport. The kinetic theory of granular flow was used to study the dynamics and interactions of cuttings transport. Non-Newtonian fluid properties were modeled using power law and Bingham plastic formulations. The simulation results demonstrated a marked improvement in efficiency, as much as 45%, in transport by increasing the fluid inlet velocity from 0.54 m/s to 2.76 m/s, reducing the amount of particle accumulation and changing axial and tangential velocity profiles dramatically, particularly at narrow annular gaps. At a 300 rpm rotation, the drill pipe brought on a spiral flow pattern, which penetrated tangential velocities in the narrow gap that had increased transport efficiency to almost 30% more. Shear-thinning behavior characterizes fluid of which the viscosity, at nearly 50% that of the central core low-shear regions, was closer to the wall high-shear regions. Fluid velocity and drill pipe rotation play a crucial role in optimizing cuttings transport. Higher fluid velocities with controlled drill pipe rotation enhance cuttings removal and prevent particle build-up, thereby giving very useful guidance on how to clean the wellbore efficiently in drilling operations.
Adaptive Reduction of Curse of Dimensionality in Nonparametric Instrumental Variable Estimation
Authors: Huang Ming-Yueh , Chan Kwun Chuen Gary
Published: December 2024

Nonparametric estimation of instrumental variable treatment effects typically builds on various nonparametric identification results. However, these estimators often face challenges from the curse of dimensionality in practice, as multi-dimensional covariates are common. To address this issue, we investigate the nonparametric identification of a range of treatment effects within different sufficient dimension reduction models. We also examine the efficiency of estimation and find that, unlike fully nonparametric approaches, nonparametric estimators derived from maximal dimension reduction based on identification results may not be efficient. We study the conditions for achieving maximal dimension reduction to ensure efficiency for a binary instrumental variable and extend these results to multivariate and general instrumental variables. The proposed nonparametric sufficient dimension reduction framework imposes no constraints on the distribution of the observed data while mitigating the curse of dimensionality in a data-adaptive manner.
Discrete-Time Retrial Queuing Systems with Last-Come-First-Served (LCFS) and First-Come-First-Served (FCFS) Disciplines: Negative Customer Impact and Stochastic Analysis
Authors: Atencia-Mckillop Iván , Sánchez-Merino Sixto , Fortes-Ruiz Inmaculada , Galán-García José Luis
Published: December 2024

This paper examines a discrete-time retrial queuing system that incorporates negative customers, system breakdowns, and repairs. In this model, an arriving customer has the option to go directly to the server, pushing the currently served customer, if any, to the front of the orbit queue, or to join the orbit based on a First-Come-First-Served (FCFS) discipline. The study also considers negative customers who not only remove the customer currently being served but also cause a server breakdown. An in-depth analysis of the model is conducted using a generating function approach, leading to the determination of the distribution and expected values of the number of customers in the orbit and the entire system. The paper explores the stochastic decomposition law and provides bounds for the difference between the steady-state distribution of this system and a comparable standard system. Recursive formulas for the steady-state distributions of the orbit and the system are developed. Additionally, it is shown that the studied discrete-time system can approximate the M/G/1 continuous-time version of the model. The research includes a detailed examination of the customer’s sojourn time distribution in the orbit and the system, utilizing the busy period of an auxiliary system. The paper concludes with numerical examples that highlight how different system parameters affect various performance characteristics, and a section summarizing the key research contributions.
Exponential Stability and ℒ1-Gain Performance for Positive Sampled-Data Control Systems
Authors: Zhao Ping , Niu Ben
Published: December 2024

This paper aims to explore the application of sampling control technology in positive Markov jump systems (PMJSs), focusing on the exponential stability in mean and L1-gain performance of the system. We first establish a PMJS model based on sampling control and conduct a detailed analysis of its exponential stability in mean. Subsequently, combined with L1-gain theory, we propose a sufficient condition for PMJSs with a prescribed L1-gain performance level, which ensures the robustness and satisfaction of performance indicators of the system in a randomly switching environment. From the sufficient conditions we have given, we can indeed see the effect of the sampling period on the system performance. Based on this sufficient condition, we further design the state feedback controller, and give the feedback gain solving algorithm based on linear programming method. A simple simulation example verifies the correctness and effectiveness of the results. The main contribution of this paper is to introduce sampling control technology into the research of PMJSs and propose a complete theoretical framework and analysis method, providing new theoretical support and practical application value for the sampling control of PMJSs.
Fast Frequency Control Strategy Based on Worst-Case Network Attack Perception
Authors: Xu Wentao , Song Zhenghang , Guan Peiyuan
Published: December 2024

A fast frequency control (FFC) strategy using the proximal policy optimization based on worst-case network attack perception (worst-case PPO) algorithm is proposed to address the complexity of fast frequency control in power systems and the risks posed by network attacks. This strategy focuses on frequency stability in power systems with a high penetration of renewable energy, and utilizes a reinforcement learning agent to intelligently adjust the power setpoint of voltage source converters (VSCs), ensuring that both the frequency and the rate of change of the frequency remain within permissible limits. Considering the potential for network attacks, this strategy adopts the robust worst-case PPO algorithm, which ensures system stability even under the worst-case attack scenarios. The experimental results demonstrate that the proposed strategy effectively prevents frequency degradation under various disturbances, exhibiting a stronger disturbance resistance and robustness compared to traditional reinforcement learning methods. Furthermore, the strategy is easy to implement, highly adaptable, and suitable for the complex and dynamic operational environment of power systems, providing strong support for the secure and stable operation of smart grids.
Deep-Sea Ecosystems as an Unexpected Source of Antibiotic Resistance Genes
Authors: Zhang Wei , Li Yingdong , Chu Yunmeng , Liu Hao , Jing Hongmei , Xia Qianfeng
Published: December 2024

The deep-sea ecosystem, a less-contaminated reservoir of antibiotic resistance genes (ARGs), has evolved antibiotic resistance for microbes to survive and utilize scarce resources. Research on the diversity and distribution of these genes in deep-sea environments is limited. Our metagenomics study employed short-read-based (SRB) and assembled-contig-based (ACB) methods to identify ARGs in deep-sea waters and sediments and assess their potential pathogenicity. SRB prediction was found to be more effective for studying the abundance and diversity of these genes, while combining both methods better illustrated the relationship of ARGs with the hosts. Deep-sea waters (DSW) and trenches had the highest diversity of ARGs, including β-lactams, multidrug resistance genes, and rifamycins. Mobile genetic elements, such as IncQ and RP4 plasmids, were also identified. The ratio of nonsynonymous to synonymous substitutions (pN/pS) values of these genes suggest different evolutionary strategies in response to deep-sea conditions and possible human impacts. These resistome profiles provide valuable insights into their natural origins as well as the ecological and evolutionary implications of antibiotic resistance in deep-sea ecosystems. The exploration of the global distribution of ARGs in diverse deep-sea environments is a novel approach that will assist in understanding their potential reservoirs and evolutionary mechanisms. Therefore, employing a comprehensive approach to studying ARGs is particularly necessary. Unique microbial life in deep-sea ecosystems, especially in deep-sea cold seeps sediments (DSCSS), deep-sea waters (DSW), and trench waters (TW), could be a valuable source of new antibiotics and resistance discovery.
NIPT Integration as a Patient-Paid Prenatal Screening Option—Observations and Challenges from a Bulgarian Genetic Counseling Center
Authors: Yahya Dinnar , Hachmeriyan Mari , Stoyanova Milena , Levkova Mariya
Published: December 2024

Background: NIPT is a widely implemented method for prenatal screening of chromosomal disorders. Its introduction initiated the practice of counseling women pre- and post-analytically. Since the test’s usage is established in different conditions, comparing data from various socioeconomic and cultural backgrounds would be of scientific value. Our study is the first to describe NIPT integration in Bulgaria. We aimed to evaluate current trends in demand and referral, the frequency of high-risk results, cases of fetal sex discrepancies and their impacts, as well as commonly held misconceptions during genetic counseling. We also address issues and necessary general prophylaxis and prenatal care improvements. Methods: We performed a retrospective analysis on the pregnant women who received GC for NIPT in our genetic center between 2016 and 2023. We separated this period into two due to a significant difference in the test’s price. A total of 635 women were included with their referral indications, panel width preference, fetal sex, and SCA. We assessed cases of fetal sex discrepancy, high-risk pregnancies, late NIPT (after GW 18), and commonly occurring issues and misconceptions. Results: We observed a significant increase in the demand for NIPT—63 women for 2016–2020 versus 572 for 2021–2023. The leading indications were supervision of normal pregnancy (50.4%) and advanced maternal age (>35 years) (31.2%). As for late NIPT, the most common indications for this late testing were high risk from a maternal serum screening test (33.3%) and anxiety (25%). Further, 1.1% of results were high-risk for trisomy 18 and 21 and monosomy X. We reviewed two cases of fetal sex discrepancy (0.3%) and common misconceptions twice more during pre-test GC. Conclusions: This single-center experience shows that demand for NIPT is exponentially growing, especially as a normal pregnancy screening method. Delivering thorough education to the community and guaranteeing outstanding care during genetic counseling sessions is crucial for fostering informed decisions and overall well-being.
Notch Fatigue Damage Evolution Mechanism of TC21 Alloy with Multilevel Lamellar Microstructures
Authors: Zhou Xiaosong , Li Xiang , Huang Chaowen , Wu Quan , Zhao Fei
Published: December 2024

This study aims to explore the effect of microstructural parameters on the notch fatigue damage behavior of the TC21 alloy. Different levels of lamellar microstructures were achieved through distinct aging temperatures of 550 °C, 600 °C, and 650 °C. The findings reveal that increasing aging temperature primarily contributes to the augmentation of α colony (αc) thickness, grain boundaries α phase (GBα) thickness, and α fine (αfine) size alongside a reduction in α lath (αlath) thickness and αfine content. The notch alters stress distribution and relaxation effects at the root, enhancing notched tensile strength while weakening plasticity. Moreover, the increased thickness of GBα emerges as a critical factor leading to the increase area of intergranular cleavage fracture. It is noteworthy that more thickness αlath and smaller αfine facilitate deformation coordination and enhance dislocation accumulation at the interface, leading to a higher propensity for micro-voids and micro-cracks to propagate along the interface. Conversely, at elevated aging temperatures, thinner αlath and larger αfine are more susceptible to fracture, resulting in the liberation of dislocations at the interface. The reduction in αlath thickness is crucial for triggering the initiation of multi-system dislocations at the interface, which promotes the development of persistent slip bands (PSBs) and dislocation nets within αlath. This phenomenon induces inhomogeneous plastic deformation and localized hardening, fostering the formation of micro-voids and micro-cracks.
Microstructure and Mechanical Properties of High-Entropy Alloy FeCoNiCr(X) Produced by Laser Directed Energy Deposition Process: Effect of Compositional Changes
Authors: Kovalenko Ekaterina , Krasanov Igor , Valdaytseva Ekaterina , Stankevich Stanislav , Klimova-Korsmik Olga , Gushchina Marina
Published: December 2024

High-entropy alloys (HEAs) have shown promise as materials with improved mechanical properties compared to traditional materials. Achieving the desired mechanical properties depends on the alloy composition, both in terms of percentage and elements. Laser directed energy deposition technology allows for the production of products with various complex geometries and dimensions (L-DED). It has been found that HEA FeCoNiCrCu alloys can be divided into regions with high concentrations of Fe + Co + Cr and Cu elements. Dendrite growth directions of HEA FeCoNiCrCu are (111) and (200), and the average microhardness is around 240 HV. All samples have cracks vertically along the height. Fine-grained and dendrite structures were observed. Cu-element is mainly found in cracks. The HEA FeCoNiCrCu alloy was compared with another HEA FeCoCrMnNi, successfully obtained by the same L-DED technology. Comparing the two HEAs FeCoNiCrCu and FeCoCrMnNi obtained with the same deposition parameters can help determine the impact of one element on the phase composition, microstructure and mechanical properties of the high-entropy alloy. Replacing the element Mn with Cu in HEA FeCoNiCrMn led to a shift in the dendrite growth from one to two predominant directions and a decrease in the average microhardness by 20%.
Creating Tunable Micro-Optical Components via Photopolymerization 3D Printing Combined with Polymer-Dispersed Liquid Crystals
Authors: Zhang Sheng-Yuan , Shih Hsi-Fu , Tien Chuen-Lin , Tu Han-Yen
Published: December 2024

Based on additive manufacturing via photopolymerization, this study combines polymer-dispersed liquid crystal (PDLC) technology with 3D printing technology to produce tunable micro-optical components with switchable diffraction or focusing characteristics. The diffraction grating and Fresnel zone plate are the research targets. Their structures are designed and simulated to achieve expected optical functions. A liquid crystal display (LCD) 3D printer is used to produce structures on transparent conductive substrates. The printed structures are filled with PDLCs and covered with transparent conductive substrates to achieve tunable functions. The proposed configurations are implemented and verified. The experimental results show that the diffraction efficiency of the 0th order increases from 15% to 50% for the diffraction grating and the focusing spot intensity decreases from 74% to 12% after the application of an electric field. These results demonstrate the feasibility of the proposed tunable optical component configurations.
Temperature Control of Quartz-Glass Melting Areas in Laser Additive Manufacturing
Authors: Chen Jing , Lv Zeping , Zhang Xuanjia , Xu Tao , Cheng Yuntao
Published: December 2024

Direct energy deposition is an additive technology that can quickly manufacture irregularly shaped quartz-glass devices. Based on this technology and coaxial laser/wire feeding, open-loop tests were conducted under different process parameters. A closed-loop temperature control system was designed and built for the molten pool temperature in quartz-glass additive manufacturing. It was based on a PID (proportional–integral–derivative) control algorithm for adjusting laser power. Changes in the macroscopic morphology, microstructure, and other qualities of the final additive result before and after the temperature control of the quartz glass were examined. Relative to constant laser powers of 120 W and 140 W, the temperature control of the multi-pass single-layer lateral additives produced dense surface microstructures of the additively produced quartz glass, and the molding quality was better.