bluuebunny/crossref_metadata_2025 huggingface dataset:
Are Vitamin D Levels Related to Sarcopenia in Children with Inflammatory Bowel Disease?
Authors: Çakar Sevim , Eren Gülin , Erdur Cahit Barış , Önder Mehmet , Pelek Şafak , Demirtaş Duygu , Bekem Özlem , Ecevit Çiğdem Ömür
Published: February 2025

Background: Data on the impacts of vitamin D deficiency on sarcopenia in pediatric patients with inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are lacking. We aimed to investigate the relationships between vitamin D levels and sarcopenia in patients with newly diagnosed IBD. Methods: A cross-sectional, retrospective study was conducted in a tertiary care children’s hospital. Pediatric IBD patients who underwent magnetic resonance (MR) enteroclysis at the time of initial diagnosis were included. Total psoas muscle area (tPMA) at the L4/L5 intervertebral level was demonstrated on MR by scanning the right and left psoas muscle areas. Sarcopenia was defined as a measurement under the 10th percentile according to MR-derived reference values of tPMA percentile charts for healthy children aged 1–18 years. Vitamin D insufficiency was defined as a serum 25-OH-D level below 30 ng/mL and deficiency as that below 20 ng/mL. Collected data from demographic evaluation, clinic, and laboratory tests were statistically assessed. Results: According to the MR-derived reference values of tPMA, 85% (n = 33) of UC and 81% (n = 21) of CD patients had sarcopenia. The severe vitamin D deficiency ratio was 35.9% (n = 14) in UC and 38.5% (n = 10) in CD. We found that vitamin D levels were similar in patients with UC and CD, while they were significantly lower in the group below the 3rd percentile of tPMA (n = 41, median 9.8) than in the group between the 3rd and 10th percentiles (n = 13, median 16.9; p = 0.038). Conclusions: Formulating strategies to recognize and prevent sarcopenia, including the prevention and—if necessary—the treatment of vitamin D deficiency, could bring multi-faceted benefits.
Antibacterial and Antibiofilm Activity of Layers Enriched with Silver Nanoparticles on Orthodontic Microimplants
Authors: Sycińska-Dziarnowska Magdalena , Ziąbka Magdalena , Cholewa-Kowalska Katarzyna , Klesiewicz Karolina , Spagnuolo Gianrico , Lindauer Steven J. , Park Hyo-Sang , Woźniak Krzysztof
Published: February 2025

Orthodontic microimplants have revolutionized anchorage in orthodontics but remain vulnerable to microbial colonization, potentially leading to infection and failure. Surface modifications incorporating silver nanoparticles (AgNPs) offer antimicrobial benefits, providing long-term protection against bacterial infections, while improving partial osseointegration. This study investigates hybrid coatings enriched with AgNPs, calcium (Ca), and phosphorus (P) to improve antimicrobial efficacy and reduce biofilm formation. Microimplants fabricated from the Ti6Al4V alloy were divided into six groups with varying surface treatments, including etching in hydrofluoric acid and hybrid layers containing 0.5 mol% AgNPs and CaP. Antibacterial activity was evaluated using agar diffusion and biofilm formation assays against S. aureus, E. coli, and S. mutans. Surface roughness was analyzed and correlated with biofilm formation. The model assessing the impact of biomaterials on S. aureus biofilm revealed a strong association (R2 = 0.94), with biomaterial choice significantly influencing biofilm formation. The model for E. coli biofilm exhibited exceptional predictability (R2 = 0.99). The model for S. mutans biofilm demonstrated an association (R2 = 0.68). Hybrid coatings exhibited a promising antimicrobial activity. Biofilm formation was higher on microimplants with rougher surfaces. Hybrid coatings enriched with AgNPs and CaP enhance antimicrobial properties and partially reduce biofilm formation. It is suggested that the optimization of microimplant surface areas varies according to function. An enhanced performance can be achieved by maintaining a smooth surface for soft tissue contact, while incorporating a rough surface enriched with bactericidal and bioactive modifiers for bone contact areas.
A Novel Metabolic Risk Classification System Incorporating Body Fat, Waist Circumference, and Muscle Strength
Authors: Robledo-Millán Carlos Raúl , Diaz-Domínguez María Regina , Castañeda-Ramírez Ari Evelyn , Quiñones-Lara Efrén , Valencia-Marín Sebastián , Suárez-García Ricardo Xopán , López-Desiderio Nely Gisela , Ramos-Cortés Claudio Adrían , Gaytán Gómez Areli Marlene , Bello-López Juan Manuel , Saldívar-Cerón Héctor Iván
Published: February 2025

Background: As metabolic diseases continue to rise globally, there is a growing need to improve risk assessment strategies beyond traditional measures such as BMI and waist circumference, which may fail to identify individuals at risk. This study develops and validates a novel metabolic risk classification system that incorporates body fat percentage (%BF), waist circumference (WC), and grip strength (GS) in Mexican adults. It aims to improve risk stratification and evaluate the association with metabolic syndrome. Methods: This cross-sectional study involved 300 young adults (18–22 years) from a university in Mexico City, utilizing body composition (%BF) and anthropometric measures (WC, GS) to categorize them into four risk groups: protective, low risk, increased risk, and high risk. A retrospective cohort of 166 adults (18–65 years) with complete clinical records was used for validation. Results: The inclusion of GS in the risk assessment significantly shifted the distribution in the young adult cohort, reducing the “no risk” category (15.5% males, 11.6% females) and expanding the higher-risk categories (70.2% males, 69% females). Metabolic parameters such as fasting glucose, triglycerides, HDL cholesterol, and blood pressure worsened progressively across the risk categories (p < 0.001). The high-risk group exhibited a markedly increased odds ratio for metabolic syndrome at 28.23 (10.83–73.6, p < 0.001), with no cases in the protective and low-risk groups. Conclusions: Integrating grip strength with %BF and WC into a risk classification system substantially enhances metabolic risk stratification, identifies at-risk individuals not previously detected, and confirms a protective group. This validated system provides a robust tool for early detection and targeted interventions, improving public health outcomes in metabolic health.
Explainable Siamese Neural Networks for Detection of High Fall Risk Older Adults in the Community Based on Gait Analysis
Authors: Kokkotis Christos , Apostolidis Kyriakos , Menychtas Dimitrios , Kansizoglou Ioannis , Karampina Evangeli , Karageorgopoulou Maria , Gkrekidis Athanasios , Moustakidis Serafeim , Karakasis Evangelos , Giannakou Erasmia , Michalopoulou Maria , Sirakoulis Georgios Ch , Aggelousis Nikolaos
Published: February 2025

Background/Objectives: Falls among the older adult population represent a significant public health concern, often leading to diminished quality of life and serious injuries that escalate healthcare costs, and they may even prove fatal. Accurate fall risk prediction is therefore crucial for implementing timely preventive measures. However, to date, there is no definitive metric to identify individuals with high risk of experiencing a fall. To address this, the present study proposes a novel approach that transforms biomechanical time-series data, derived from gait analysis, into visual representations to facilitate the application of deep learning (DL) methods for fall risk assessment. Methods: By leveraging convolutional neural networks (CNNs) and Siamese neural networks (SNNs), the proposed framework effectively addresses the challenges of limited datasets and delivers robust predictive capabilities. Results: Through the extraction of distinctive gait-related features and the generation of class-discriminative activation maps using Grad-CAM, the random forest (RF) machine learning (ML) model not only achieves commendable accuracy (83.29%) but also enhances explainability. Conclusions: Ultimately, this study underscores the potential of advanced computational tools and machine learning algorithms to improve fall risk prediction, reduce healthcare burdens, and promote greater independence and well-being among the older adults.
Recognition of Underwater Engineering Structures Using CNN Models and Data Expansion on Side-Scan Sonar Images
Authors: Du Xing , Sun Yongfu , Song Yupeng , Dong Lifeng , Tao Changfei , Wang Dong
Published: February 2025

Side-scan sonar (SSS) is a critical tool in marine geophysical exploration, enabling the detection of seabed structures and geological phenomena. However, the manual interpretation of SSS images is time-consuming and relies heavily on expertise, limiting its efficiency and scalability. This study addresses these challenges by employing deep learning techniques for the automatic recognition of SSS images and introducing Marine-PULSE, a specialized dataset focusing on underwater engineering structures. The dataset refines previous classifications by distinguishing four categories of objects: pipeline or cable, underwater residual mound, seabed surface, and engineering platform. A convolutional neural network (CNN) model based on GoogleNet architecture, combined with transfer learning, was applied to assess classification accuracy and the impact of data expansion. The results demonstrate a test accuracy exceeding 92%, with data expansion improving small-sample model performance by over 7%. Notably, mutual influence effects were observed between categories, with similar features enhancing classification accuracy and distinct features causing inhibitory effects. These findings highlight the importance of balanced datasets and effective data expansion strategies in overcoming data scarcity. This work establishes a robust framework for SSS image recognition, advancing applications in marine geophysical exploration and underwater object detection.
Underwater Target Tracking Method Based on Forward-Looking Sonar Data
Authors: Zeng Wenjing , Li Renzhe , Zhou Heng , Zhang Tiedong
Published: February 2025

Underwater dynamic targets often display significant blurriness in their forward-looking sonar imagery, accompanied by sparse feature representation. This phenomenon presents several challenges, including disturbances in the trajectories of underwater targets and alterations in target identification throughout the tracking process, thereby complicating the continuous monitoring of moving targets. This research proposes a new framework for underwater acoustic data interpolation and underwater object tracking. Considering the character of underwater acoustic images, a Swin Transformer is integrated in the architecture of the YOLOv5 network; then, an improved Deep Simple Online and Real-time Tracking method is developed. By enlarging the bounding box output generated by the detector and subsequently integrating it into the tracker, the sensing horizon of the tracker is broadened. This strategy enables the extraction of noise features surrounding the target, thereby augmenting the target’s characteristics and improving the stability of the tracking process. The experimental results demonstrate that the proposed method effectively reduces the frequency of changes in target identification numbers, minimizes the occurrence of trajectory interruptions, and decreases the overall percentage of trajectory interruptions. Additionally, it significantly enhances tracking stability, particularly in scenarios involving intersecting target paths and encounters.
Value Priorities of Student Youth in the Multi-Ethnic Space of Kazakhstan and Their Influence on Intercultural Communications
Authors: Zharkynbekova Sholpan , Shakhputova Zukhra , Galiyeva Bakhyt , Absadyk Almasbek
Published: February 2025

This article aims to describe the value priorities of Kazakhstani student youth and explore their relationship with traditions, the culture of ethnic groups in Kazakhstan, state ideological attitudes, and the influence of external cultures. This paper addresses the impact of the multinational environment and globalization on the formation of values among students in Kazakhstan. This article analyzes empirical data collected through a mixed-methods questionnaire, developed in accordance with the well-known value measurement methodologies of M. Rokeach and Sh. Schwartz. The results show that although traditional values remain significant, the growing exposure of young people to global influences and socio-political changes indicates a dynamic evolution of their value system, reflecting both continuity and changes in the cultural landscape of Kazakhstan. The key value for Kazakhstani students is family, which suggests sufficient harmony in the life models chosen by these students. The significance of this study lies in its potential to contribute to the establishment of a system of relations in which different cultures can engage in dialogue, preserve their historical trajectories, and maintain mutual respect among representatives of diverse ethnicities and social groups. This study also holds implications for the development of legislative mechanisms aimed at respecting Kazakhstan’s national interests in international communication.
How Customer Avoidance Leads to Customers Returning: A Longitudinal Study Concerning Online Travel Agencies
Authors: Su Zerui , Ha Hong-Youl
Published: February 2025

Customers’ intentions to avoid a product or service tend to be dynamic. Thus, this study aims to explore the influence of trajectory changes in customers’ avoidance after service recovery on relationship strength, negative word-of-mouth (WOM) intentions, and revisit intentions. Using a longitudinal approach with three-month lag intervals, we implement a latent growth model analysis to test our proposed hypotheses. Our findings demonstrate that customers’ desire to engage in avoidance after a service failure evolves, but its impact wanes. As avoidance decreases, negative WOM intentions likewise decline, and intentions to revisit a firm (which, in this study, is a travel agency) increase, thereby attenuating an avoidance-becomes-defection effect over time. Meanwhile, relationship strength initially grows but then weakens after service recovery. In contrast, negative WOM intentions slightly decrease from the early to mid-stage, followed by an increase in the late stage. Furthermore, relationship strength does not affect negative WOM or revisit intentions at the subsequent service recovery phase. Our findings offer innovative insights into upgrading customer avoidance perspectives regarding service recovery. We also present managerial implications regarding service recovery and customer relationship strategies that vary over time.
Spatiotemporal Dynamics of Urban Green Spaces and Climatic Vulnerability of Togolese Cities in the Context of Rapid Urbanisation: The Case of Lome and Kara
Authors: Deton Yetondé , Kamou Hodabalo , Atato Abalo , Kombate Bimare , Mabafei Abalo , Yoka Josef , Dourma Marra , Guelly Atsu Kudzo , Batawila Komlan , Akpagana Koffi
Published: February 2025

In Togo, the cities of Lomé and Kara are undergoing rapid urbanisation driven by strong population growth and the expansion of urban built-up areas, leading to significant reductions in urban green spaces (UGSs). UGSs are vital for climate regulation and human well-being by mitigating urban heat, improving air quality, and supporting mental health. This urban expansion directly replaces vegetated areas with impervious surfaces, diminishing UGS and their associated ecosystem services. Consequently, climatic vulnerability has increased, highlighting the need for sustainable urban development and UGS conservation. This study examines UGS spatiotemporal dynamics using Landsat imagery from 1988, 2000, 2012, and 2022, applying a supervised image classification approach with the maximum likelihood algorithm. Post-classification change detection quantified UGS loss. Additionally, vulnerability models for 2022, 2060, and 2100 were developed using Shared Socioeconomic Pathways (SSP 2.45 and SSP 5.85) and a multifactorial modelling approach. The results reveal a decline in UGSs from 85.98% to 40.78% in Lomé and from 93.99% to 36.68% in Kara between 1988 and 2022, primarily due to urbanisation. Vulnerable zones, currently in UGSs, risk disappearance by 2060–2100, exacerbating climate risks. Urgent measures are needed, including conservation policies, UGS creation, and community awareness to promote urban sustainability.
Effects of Intermetallic NiAl Particle Content on Friction and Wear of Spark Plasma-Sintered Alumina Matrix Composites
Authors: Khun Nay Win , Huang Mingyue , Li Zhong Alan , Zhang He , Khor Khiam Aik , Yang Jinglei , Duan Fei
Published: February 2025

The spark plasma sintering (SPS) technology was applied to develop alumina matrix composites (Al2O3MCs) with different nickel-aluminium (NiAl) particle contents of 5–20 wt.% to understand a correlation between their NiAl particle contents and their microstructures, fracture, hardness, friction, and wear. The incorporation of NiAl particles suppressed micrograins and micropores in the microstructures of the Al2O3MCs, which resulted in their improved fracture resistance. Increasing the NiAl particle content from 0 to 20 wt.% gave rise to a 23.9% decrease in the hardness of the Al2O3MCs. The Al2O3MCs had 18.2% and 13.3% decreases in their friction coefficients and 68.3% and 81.3% decreases in their specific wear rates under the normal loads of 2 and 6 N, respectively, with an increased NiAl particle content from 0 to 20 wt.% thanks to their decreased fatigue wear. The SPS Al2O3MCs with NiAl particles had promising tribological performance for rotating gas turbine components.
Interaction Lubrication Mechanism Between Nano-Biochar and Traditional Oil Additives Under Various Sliding Conditions
Authors: Guan Weiwei , Hou Xianjun , Wang Youheng , Chu Chen , Ali Mohamed Kamal Ahmed
Published: February 2025

The development of green lubrication requires nano-lubricants to possess more environmentally friendly fabrication modes and materials with superior tribological properties. This study investigates the tribological properties of nano-biochar in PAO6 base oil and in combination with different additives. The effect of adsorption on friction reduction and anti-wear performance is demonstrated by replacing the friction sub-materials in the four-ball friction test. Based on the comparison of wear region characterization, the incorporation of nano-biochar improves the friction reduction performance of detergent and dispersant base oils with a reduction in coefficient of friction (COF) by 16.7% and 19.0%, respectively, and produces a synergistic effect on the anti-wear performance. When nano-biochar is compounded with anti-wear agents and friction reducer, there is a synergistic effect on friction reduction performance, and COF decreases by 9.4% and 4.5% compared with anti-wear agents and friction reducer base oils, respectively. A method to analyze the friction reduction and anti-wear mechanism of nano-additives in complex lubrication system is proposed, which reveals in depth the interaction law and synergistic lubrication mechanism between NBC and additives in the friction process.
A Facile and Rapid Method for Synthesizing Indole–Chalcone Hybrids
Authors: Tanyi Solange A. , Eni Donatus B. , Abdelsalam Mohamed , Schmidt Matthias , Sippl Wolfgang , Ntie-Kang Fidele
Published: February 2025

Indole–chalcone hybrids are a large group of compounds known for their excellent biological properties the help combat diverse pathogens. This study describes a rapid synthetic pathway for the synthesis of ten indole–chalcone hybrids, namely, 3(a–j), from 1-Boc-3-formylindole (1) and acetophenone derivatives (2), in a one-pot approach. This synthesis involved an initial condensation reaction and subsequent deprotection of the Boc group. 1H-NMR, 13C-NMR, and MS were used to elucidate the structures of the final compounds. Contrary to previous methods for the synthesis of indole–chalcone hybrids, this novel synthetic method, which involves using a Boc-protected indole via microwave-assisted synthesis, is advantageous because it is a one-pot approach, making it facile and rapid.
The Effectiveness of Different Additives on Concrete’s Freeze–Thaw Durability: A Review
Authors: Abbas Moutaman M. , Muntean Radu
Published: February 2025

Enhancing concrete’s resilience against freeze–thaw (F-T) cycles is a critical challenge in civil engineering, especially in cold climates, where repeated freezing and thawing lead to structural degradation. This review explores the effectiveness of various additives, including supplementary cementitious materials (SCMs) and chemical admixtures, in improving concrete durability under F-T conditions. Factors influencing F-T resistance include the type and percentage of SCM replacement, the water–cement ratio, pore structure refinement, and air entrainment. The mechanisms by which additives enhance the durability—such as reducing the permeability, improving the microstructure, and increasing the compressive strength—are examined through an extensive review of experimental studies. The findings indicate that manufactured additives, such as silica fume, metakaolin, nano-SiO2, and graphene oxide, significantly enhance the F-T durability by densifying the concrete matrix and mitigating internal damage. In contrast, natural additives, including rice husk ash and zeolite, show potential but require optimization to match the performance of industrial SCMs. Additionally, the preparation and treatment methods of these materials play a crucial role in their effectiveness. This review provides insights into optimizing concrete formulations to enhance the longevity and sustainability, offering practical recommendations for the use of SCMs in cold climates.
Additive Manufacturing of Vapor Chambers
Authors: Chen Kuan-Lin , Hsu Shao-Chi , Kang Shung-Wen
Published: February 2025

The increasing power density of high-performance electronic devices poses significant thermal management challenges. Vapor chambers (VCs) offer efficient heat dissipation, but traditional manufacturing methods limit their structural precision and performance. This study investigates the thermal performance of VCs fabricated with additive manufacturing (AM), featuring triply periodic minimal surface (TPMS) Gyroid capillary structures at two fill ratios under varying thermal loads. Enhanced thermal stability and performance were observed in the higher fill ratio, particularly under higher heat loads, whereas the lower fill ratio excelled under low-heat conditions, achieving a thermal resistance as low as 0.3688 K/W at an 80 W heat load. Additionally, the research explored the advantages and challenges of horizontal and vertical printing techniques in VC fabrication. Horizontal printing was found to compromise cavity volume due to necessary support structures, whereas vertical printing enhanced mass production feasibility and maintained effective vapor circulation. This study proposes a novel approach using AM to manufacture VCs as a monolithic structure. By eliminating the need for welding, this method ensures seamless integration of the capillary structure with the housing, thereby avoiding issues related to poor contact or welding-induced damage. The study confirmed a 75% reduction in thermal resistance in VCs with capillary structures compared to those without under similar conditions, highlighting the significant potential of integrating precisely designed capillary structures and additive manufacturing in improving vapor chamber performance for advanced thermal management applications.
Comprehensive Performance Evaluation of Epoxy Reclaimed Asphalt and Mixtures
Authors: Tian Junhao , Guo Dedong , Xu Qi , Wu Jiang , Sun Xupeng , Wang Li , Riccardi Chiara
Published: February 2025

In order to improve the reclaimed asphalt pavement (RAP) dosing and the road performance of recycled asphalt mixtures, this study prepared epoxy recycled binder (ERB) and epoxy recycled mixtures (ERMs) by dosing epoxy asphalt, respectively. The rheological characteristics and microstructure of ERB were comprehensively analyzed using a dynamic shear rheometer (DSR), a bending beam rheometer (BBR), and fluorescence microscopy (FM). The road performance of ERM was evaluated by a four-point bending test, a rutting test, trabecular beam bending test, a freeze–thaw splitting test, an immersion Marshall test, and a uniaxial compression dynamic modulus test. Grey relational analysis (GRA) was used to quantify the correlation between the dosage of epoxy system and road performance indicators. The results show that, after the addition of the epoxy system, the high- and low-temperature rheological properties of ERB were improved by 458.3% and 97.9% compared with those of ordinary asphalt, and the high-temperature performance and fatigue performance of ERM were improved by 220.4% and 80.5% compared with SBS-modified asphalt mixtures. The dynamic modulus test showed that the dynamic modulus of ERM was positively correlated with the dosage of epoxy system. GRA showed that the dosage of epoxy system was most closely related to the fatigue performance of recycled mixtures.
The Formation of an Interface and Its Energy Levels Inside a Band Gap in InAs/GaSb/AlSb/GaSb M-Structures
Authors: Śliż Paweł , Jarosz Dawid , Pasternak Marta , Marchewka Michał
Published: February 2025

We studied specially designed InAs/GaSb/AlSb/GaSb M-structures, a type-II superlattice (T2SL), that can serve as active materials for short-wavelength infrared (SWIR) applications. To obtain the dispersion relation of the investigated M-structures, k·p perturbation theory based on the eight-band model implemented in the nextnano++ v1.18.1 (nextnano GmbH, Munich, Germany) software was used. Numerical band-gap engineering and dispersion calculations for the investigated M-structures (composed of 6/1/5/1 monolayers, with InSb interfaces included) revealed the presence of an additional energy level within the energy gap. This energy level originates from the InSb-like interfaces and does not appear in structures with different layer or interface thicknesses. Its properties strongly depend on interface thickness, temperature, and strain. Numerical calculations of the probability density function |Ψ|2, absorption coefficients, and optical absorption spectra at varying temperatures demonstrate that, under specific conditions, such as an optimised interface thickness and temperature, optical absorption increases significantly. These theoretical results are based on structures fabricated using molecular-beam epitaxy (MBE) technology. High-resolution X-ray diffraction (HRXRD) measurements confirm the high crystallographic quality of these M-structures.
Metallurgical and Mechanical Properties of Stellite 6 Deposition Developed Through Friction Surfacing Technique
Authors: Khan Mohammad Faseeulla , Damodaram Ramachandran , Altammar Hussain , Karthik Gangaraju Manogna
Published: February 2025

Friction surfacing (FS) is a solid-state process for depositing metallurgically bonded coatings for corrosion and wear protection. It is particularly attractive for depositing coatings in materials that are difficult to fusion deposit. Stellite 6 is one such material, which is widely used as a protective coating on steel structures to combat wear and corrosion. In the current study, Stellite 6 was successfully friction-surfaced on low carbon steel plates without using any preheating. The microstructures and wear behavior of Stellite 6 coatings produced using FS were comparatively investigated with those produced using the plasma transferred arc (PTA) process. The PTA coatings showed a cast microstructure consisting of γ-dendrites and an inter-dendritic carbide network. On the other hand, the FS coatings showed a wrought microstructure with dynamically recrystallized grains and fine, uniformly distributed carbide particles. The FS coatings also showed uniform composition across the coating thickness and were undiluted, while the PTA coatings showed significant dilution as well as strong local variations in chemistry. The FS coatings exhibited a 22% increase in hardness (550 HV) compared to the PTA coatings (450 HV). Pin-on-disc dry sliding wear tests showed that the FS coatings (1.205 mm3) were more wear resistant compared to the PTA coatings (6.005 mm3), highlighting their superior mechanical performance. This study uniquely demonstrates the feasibility of depositing Stellite 6 coatings using FS without the need for preheating or post-deposition heat treatments, while achieving superior microstructural refinement, hardness, and wear resistance compared to conventional PTA coatings.
Investigation of Distortion, Porosity and Residual Stresses in Internal Channels Fabricated in Maraging 300 Steel by Laser Powder Bed Fusion
Authors: Silva Bruno Caetano dos Santos , Callegari Bruna , Seixas Luã Fonseca , Król Mariusz , Sitek Wojciech , Matula Grzegorz , Krzemiński Łukasz , Coelho Rodrigo Santiago , Batalha Gilmar Ferreira
Published: February 2025

The use of parts containing internal channels fabricated by laser powder bed fusion (LPBF) in maraging steel is gaining attention within industry, due to the promising application of the material in molds and forming tools. However, LPBF processing has issues when it comes to unsupported channels, leading to defects that can result in a limited performance and shortened component life. The present study aims to provide a detailed evaluation of the metallurgical effects arising from the LPBF printing of channels made of maraging 300 steel. The results show that channel distortion occurs due to the lack of support, associated with increased roughness at the top part of the channel profile caused by partial melting and loosening of the powder. Statistical analyses showed that distortion is significantly affected by channel length. A high level of porosity derived from a lack of fusion was observed in the region above the channel and was attributed to layer irregularities caused by the absence of support, with a predominance of large and irregular pores. Residual stresses, always of a tensile nature, present a behavior opposed to that of distortion, increasing with increases in length, meaning that higher levels of distortion lead to an enhanced effect of stress accommodation/relief, with porosity having a similar effect. All these phenomena, however, did not seem to affect crystallographic orientation, with a nearly random texture in all cases, most likely due to the energy input used and to an optimized laser scanning strategy. These findings are vital to increase the amount of attention paid towards the design of internal channels, especially with those with the purpose of coolant circulation, since distortions and poor surface finishing can reduce cooling efficiency due to a defective fluid flow, while porosity can have the same effect by hindering heat transfer. Residual stress, in its turn, can decrease the life of the component by facilitating cracking and wear.
Structural Properties of Optimal Maintenance Policies for k-out-of-n Systems with Interdependence Between Internal Deterioration and External Shocks
Authors: Kasuya Mizuki , Jin Lu
Published: February 2025

Many modern engineering systems, such as offshore wind turbines, rely on k-out-of-n configurations to ensure reliability. These systems are exposed to both internal deterioration and external shocks, which can significantly impact operational efficiency and maintenance costs, necessitating optimal maintenance policies. This study investigates an optimal condition-based maintenance policy for a k-out-of-n system, where each unit deteriorates independently following a gamma process and is subject to random external shocks that cause sudden jumps in deterioration. This study considers (1) stochastic dependencies among units, where shock-induced cumulative deterioration in one unit affects others, and (2) interdependencies between external shocks and internal deterioration, where internal deterioration influences external factors and vice versa. Using a Markov decision process framework, we derive an optimal maintenance policy that minimizes expected maintenance costs while incorporating these interdependencies. Under reasonable assumptions, we establish key structural properties of the optimal policy, enabling its efficient identification. A case study on offshore wind turbines demonstrates the effectiveness of the proposed approach, achieving up to a 9.9% reduction in maintenance costs compared to alternative policies. This cost reduction is achieved by optimizing the timing of preventive maintenance while incorporating the two aforementioned types of dependence into the decision-making process. Sensitivity analyses further explore the effects of cost parameters, deterioration rates, and shock characteristics, offering valuable insights into designing maintenance strategies for systems influenced by shocks and interdependent deterioration.
Computational Algorithm Based upon Dirichlet Boundary Conditions: Applications to Neutron Holograms
Authors: Molina de la Peña Ignacio , Calvo Maria L. , Alvarez-Estrada Ramón F.
Published: February 2025

Neutron optics is a branch of both neutron physics and quantum physics that focuses on the study of the optical properties of slow neutrons and their dual behavior as both waves and particles. In previous research, we developed a mathematical framework based on Dirichlet boundary conditions to describe the propagation of slow neutrons in space. This approach facilitated the creation of an innovative algorithm distinguished by its computational efficiency and versatility. We applied this algorithm to the digital computation of hologram recording and reconstruction for wavelengths typical of thermal neutrons. The results demonstrate that the algorithm provides significant advantages, including rapid computation and broad applicability. It effectively handles scenarios analogous to those encountered in classical holography and shows promise for extension to other areas of physical interest.
Solving Inverse Wave Problems Using Spacetime Radial Basis Functions in Neural Networks
Authors: Liu Chih-Yu , Ku Cheng-Yu , Chen Wei-Da , Lin Ying-Fan , Lin Jun-Hong
Published: February 2025

Conventional methods for solving inverse wave problems struggle with ill-posedness, significant computational demands, and discretization errors. In this study, we propose an innovative framework for solving inverse problems in wave equations by using deep learning techniques with spacetime radial basis functions (RBFs). The proposed method capitalizes on the pattern recognition strength of deep neural networks (DNNs) and the precision of spacetime RBFs in capturing spatiotemporal dynamics. By utilizing initial conditions, boundary data, and radial distances to construct spacetime RBFs, this approach circumvents the need for wave equation discretization. Notably, the model maintains accuracy even with incomplete or noisy boundary data, illustrating its robustness and offering significant advancements over traditional techniques in solving wave equations.
Evolutionary Dynamics in Data Trading with Risk Compensation
Authors: Qian Jun , Sun Xiao , Chai Yueting , Xue Xiao
Published: February 2025

The fact that data can be privately possessed yet contain the attributes of public goods leads to the “Arrow’s Information Paradox” in data trading. If left unchecked, supply-side deception about data quality and demand-side data leakage can seriously undermine the trust between suppliers and demanders. Inspired by the ideas of reputation and punishment, this paper combines a risk compensation mechanism, which is widely available in the financial sector, with data trading. Specifically, we propose a data trading model with risk compensation and study the evolutionary dynamics of the population using evolutionary game theory. We define λ as the demander’s compensation share that the supplier has to bear for data quality cheating and η as the supplier’s compensation share that the demander has to bear for data leakage. Through numerical solution and simulation, we analyze the evolutionary stable states of the population and find that the risk compensation mechanism in some data trading scenarios can limit the supply side from cheating on data quality or the demand side from leaking data. The results show that λ and η act asymmetrically, with λ being able to affect both supply-side and demand-side strategies, while η affects only the demand-side strategy. This work reveals chaos and asymmetry in data trading with risk compensation, and the proposed model and replication dynamic equations may have implications for future research.
Efficient Identity-Based Universal Designated Verifier Signature Proof Systems
Authors: Yang Yifan , Zhou Xiaotong , Su Binting , Wu Wei
Published: February 2025

The implementation of universal designated verifier signatures proofs (UDVSPs) enhances data privacy and security in various digital communication systems. However, practical applications of UDVSP face challenges such as high computational overhead, onerous certificate management, and complex public key initialization. These issues hinder UDVSP adoption in daily life. To address these limitations, existing solutions attempt to eliminate bilinear pairing operations, but their proposal still involves cumbersome certificate management and inherent interactive operations that can sometimes significantly degrade system efficiency. In this paper, we first utilize the identity-based (ID-based) SM2 digital signature scheme to construct an ID-based UDVSP system which sidesteps the cumbersome certificate management issue. To further remove the interactive requirement, we also employ the OR proof and Fiat–Shamir technologies to design the other ID-based UDVSP system. Our designs not only possess the same bilinear pairing-free advantage as Lin et al.’s proposal, but also achieve the certificate-free or non-interactive goals. Security proofs and performance analysis confirm the viability and efficiency of our systems.
Next Arrival and Destination Prediction via Spatiotemporal Embedding with Urban Geography and Human Mobility Data
Authors: Li Pengjiang , Wang Zaitian , Zhang Xinhao , Wang Pengfei , Liu Kunpeng
Published: February 2025

With the development of transportation networks, countless trajectory data are accumulated, and understanding human mobility from traffic data could be helpful for smart cities, urban computing, and urban planning. Extracting valuable insights from traffic data, such as taxi trajectories, can significantly improve residents’ daily lives. There are many studies on spatiotemporal data mining. As we know, arrival prediction or regional function detection encompasses important tasks for traffic management and urban planning. However, trajectory data are often mutilated because of personal privacy and hardware limitations, i.e., we usually can only obtain partial trajectory information. In this paper, we develop an embedding method to predict the next arrival using the origin–destination (O-D) pair trajectory information and point of interest (POI) data. Moreover, the embedding information contains region latent features; thus, we also detect the regional function in this paper. Finally, we conduct a comprehensive experimental study on a real-world trajectory dataset. The experimental results demonstrate the benefit of predicting arrivals, and the embedding vectors can detect the regional function in a city.
Hot-Deformed Microstructure and Texture of Ti-62222 Alloy
Authors: Park Chanho , Jo Haeju , Kim Jae H. , Yeom Jongtaek , Kang Namhyun , Lee Wookjin
Published: February 2025

The Ti-62222 (Ti-6Al-2Sn-2Zr-2Mo-2Cr) alloy has considerable potential for structural applications in the aerospace industry owing to its exceptional fracture resistance and specific strength. This study investigates the influence of local strain parameters and solution treatment and aging (STA) on the microstructure, texture evolution, and microhardness of a hot-forged Ti-62222 alloy. The strain distribution was simulated using the finite element method (FEM). The results showed that in the specimens before heat treatment, the morphology of the primary Ti α phase grains elongated perpendicular to the compression direction as the strain increased. In contrast, the post-heat-treated specimens (PHTSs) exhibited similar aspect ratios, regardless of the strain level, owing to grain spheroidization induced by the STA heat treatment process. Spheroidal primary Ti α phase and acicular Ti α’ phase were observed in the specimens before and after heat treatment. Texture analysis revealed that the specimens subjected to heat treatment had a weaker texture than the before-heat-treatment specimens. The near (112¯0)//FD texture tended to develop along the direction perpendicular to the forging direction. The microhardness analysis results indicated that strain had no significant effect on the microhardness of either the as-forged specimen or the PHTS. After heat treatment, the specimens showed consistent microhardness values regardless of the strain level. The PHTS exhibited increased microhardness, attributed to the aging process during STA.
Modification of Desulfurization Slag for Hot Metal Bearing V-Ti and Industry Application
Authors: Chen Jun , Chen Lian , Wang Lijun
Published: February 2025

In view of the high loss of iron during hot metal desulfurization treatment at Pangang Steel, the factors influencing slag skimming iron loss were analyzed thoroughly by thermodynamic calculation with the aid of FactSage. A desulfurization modifier containing Na2O and Al2O3 was designed. An industrial verification test was conducted for the newly designed calcium-based agent. The test results indicate that adding 8% of the modifier to the passivating lime achieves the optimal modification effect on the desulfurization slag. After modifying the desulfurization slag, the consumption of magnesium powder for every 0.001% sulfur removed decreased from 0.0149 kg to 0.0136 kg, the iron loss during slag skimming reduced from 3.52% to 2.28%, and the average slag skimming time shortened by 1.5 min. These improvements significantly lowered production costs, enhanced desulfurization efficiency, and laid the foundation for the widespread application of the semi-steel silicon addition process.
WalK(S221P) Mutation Promotes the Production of Staphylococcus aureus Capsules Through an MgrA-Dependent Pathway
Authors: Guo Zuwen , Peng Huagang , Shang Weilong , Yang Yi , Hu Zhen , Rao Yifan , Huang Xiaonan , Dou Jianxiong , Xu Zihui , Rao Xiancai
Published: February 2025

Staphylococcus aureus is a vital pathogen causing clinical infections. Capsules are important virulence factors for S. aureus. This study investigates the regulatory mechanisms underlying capsule production in S. aureus. Bacterial strains XN108 and Newman were used, and combined approaches like RNA sequencing (RNA-seq), RT-qPCR, transmission electron microscopy (TEM), gene reporter, and electrophoretic mobility shift assay (EMSA) were performed to test the role and mechanism of WalK(S221P) mutation in S. aureus capsule production. RNA-seq showed an increased expression of cap genes in the WalK(S221P)-carried S. aureus XN108 relative to the mutation-cured XN108-R. TEM and capsular polysaccharide determination demonstrated that XN108 produced more capsules than XN108-R did. Similar results were presented in the WalK(S221P)-contained K-Newman versus the wild-type Newman. RT-qPCR screening showed an increasing expression of the mgrA gene in XN108 versus XN108-R. Gene reporter and EMSA analysis revealed that WalK(S221P) mutation promoted S. aureus capsule production through MgrA. Deletion of mgrA decreased the WalK(S221P)-mediated capsule yield. Moreover, WalK(S221P) mutation remarkably increased the tolerance of S. aureus to whole blood killing and microphage phagocytosis. Overall, these data provide mechanistic insights into the effect of WalK(S221P) on the capsule production of S. aureus, which may set down foundations for future S. aureus virulence investigations.
Lipid Production in Cultivable Filamentous Fungi Isolated from Antarctic Soils: A Comprehensive Study
Authors: Gallardo Victor , Costa Jéssica , Sepúlveda Marcela , Cayún Yasna , Santander Christian , Ponce Excequel , Bittencourt Juliana , Arriagada César , Soto Javiera , Pedreschi Romina , Vicente Vania Aparecida , Cornejo Pablo , Santos Cledir
Published: February 2025

Antarctic soil represents an important reservoir of filamentous fungi (FF) species with the ability to produce novel bioactive lipids. However, the lipid extraction method is still a bottleneck. The objective of the present work was to isolate and identify cultivable FF from Antarctic soils, to assess the most effective methods for fatty acid (FA) extraction, and to characterise the obtained lipids. A total of 18 fungal strains belonging to the Botrytis, Cladosporium, Cylindrobasidium, Mortierella, Penicillium, Pseudogymnoascus, and Talaromyces genera and the Melanommataceae family were isolated and identified. The Folch, Bligh and Dyer, and Lewis extraction methods were assessed, and methyl esters of FA (FAMEs) were obtained. The Lewis method was the best in recovering FAMEs from fungal biomass. A total of 17 FAs were identified, and their chemical compositions varied depending on fungal species and strain. Oleic, linoleic, stearic, and palmitic acids were predominant for all fungal strains in the three assessed methods. Among the analysed strains, Cylindrobasidium eucalypti, Penicillium miczynskii, P. virgatum, and Pseudogymnoascus pannorum produced high amounts of FA. This suggests that the soils of Antarctica Bay, as well as harbouring known oleaginous fungi, are also an important source of oleaginous filamentous fungi that remain poorly analysed.
Discovering Ecological Interactions Between Biocontrol Bacterial Strains and Entomopathogenic Nematodes in Button Mushroom Production
Authors: Potočnik Ivana , Šantrić Ljiljana , Luković Jelena , Grujić Nikola , Anđelković Nikola , Majić Ivana , Drobnjaković Tanja , Marčić Dejan , Milijašević-Marčić Svetlana
Published: February 2025

The substrate for button mushroom (Agaricus bisporus) cultivation includes a highly complex microbiome. The aim of the study was to evaluate ecological interactions (synergistic, antagonistic, or additive) between a commercial population of the entomopathogenic nematode Steinernema feltiae (EPN) and beneficial microorganisms, bacterium Bacillus amyloliquefaciens B-241 (BA) or actinobacterium Streptomyces flavovirens A06 (SF). Their relationships were evaluated in efficacy against the pathogenic fungus Trichoderma aggressivum and the fungus gnat Lycoriella ingenua. Moreover, their impact on mushroom yield was estimated. The synergy factor was calculated as the ratio of observed to expected values regarding their efficacy against T. aggressivum/L. ingenua and influence on mushroom production. Additive relationships in efficacy against T. aggressivum were observed between EPN and BA or SF. As for the impact on yield, synergistic interactions were indicated between each beneficial microorganism and EPN. Considering suppression of L. ingenua, a mild antagonistic reaction between EPN and each beneficial microorganism was observed in plots without T. aggressivum and additive in plots inoculated with the pathogenic fungus, although high efficacy was achieved in all combinations (>80%). Tested native strains of both beneficial microorganisms could be combined with the commercial EPN strain for successful biological pest and disease control in mushroom production.