bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Four Methods to Determine the Degree of Cure of Melamine-Based Direct Pressed Laminates on Particleboards: Two Improved UV Absorption Methods, the Kiton Test, and Near Infrared Spectroscopy
Authors: Meder Mark , Mai Carsten , Lukowsky Dirk
Published: December 2024

Despite its importance, the determination of the degree of cure of melamine-based laminates often relies on tests with limited accuracy and validity. Undercured surfaces may suffer insufficient resistance to scratching and heat as well as substandard surface quality. Overcured melamine surfaces tend to crack and entail the inefficient utilization of the press—the panels could have been pressed for a shorter time. Four methods to determine the degree of cure of a melamine resin coating under industrial conditions were compared: the Kiton test, the most common method in industry, Near Infrared Spectroscopy (NIR) as a modern technique that allows for inline-measurements, and two novel hydrolysis methods. Each test was conducted on the same 18 panels. Each panel differed in its resin system or its degree of cure, which was adjusted by varying the pressing duration and temperature. The four methods tested were all capable of determining the degree of cure to some extent, but their applicability, the delay between the curing of the melamine resin at the final stage of production and the availability of results, and the investment and workload differ greatly. Determining the critical overcure turned out to be the major challenge. Differentiation between slight overcure, which did not affect the cracking resistance, and severe overcure, which produced surfaces with a high tendency to cracking, was possible using the NIR-based method and the two novel hydrolysis methods but not with the widely used Kiton test.
Chromium Substitution Extraction Method for Its Recovery from Chromium-Tanned Leather Waste
Authors: Świerczek Lesław , Hercel Paulina , Konkol Izabela , Kuligowski Ksawery , Cenian Adam
Published: December 2024

The leather industry generates significant amounts of waste, including chromium-tanned leather waste (CTLW), which poses environmental and health hazards due to chromium’s potential toxicity. Efficient management of CTLW is crucial for environmental sustainability and resource recovery. Various methods exist for chromium recovery, including physical, chemical, and biological processes, with chemical methods, particularly substitution extraction using organic acids, showing promising results. This study investigates the use of organic acids for the substitution extraction of chromium from CTLS, with a focus on safety by monitoring the concentration of toxic chromium (VI). It was found that oxalic acid (OA) at a temperature of 43.6 °C and a concentration of 1.34% achieved an extraction efficiency of 63.1% while maintaining minimal hydrolysis at 0.70%. This method offers a sustainable and environmentally friendly approach to chromium extraction from CTLW, addressing a critical need in waste management practices.
Histomorphometric Assessment of Non-Decalcified Plastic-Embedded Specimens for Evaluation of Bone Regeneration Using Bone Substitute Materials—A Systematic Review
Authors: Rogova Varvara-Velika , Peev Stefan , Yotsova Ralitsa , Gerova-Vatsova Tsvetalina , Parushev Ivaylo
Published: December 2024

With the implementation of bone substitute materials, regeneration strategies have inevitably evolved over the years. Histomorphometry is the optimal means of quantitative evaluation of bone structure and morphology. This systematic review focuses on determining study models, staining methods and histomorphometric parameters used for bone regeneration research on non-decalcified plastic-embedded specimens over the last 10 years. After being subjected to the inclusion and exclusion criteria, 118 studies were included in this review. The results establish the most commonly selected animal model is rat, followed by rabbit, sheep and dog. Strong preference for staining samples with toluidine blue was noted. With regard to histomorphometric parameters, terms related to bone were most frequently assessed, amounting to almost half of recorded parameters. New bone formation was the main descriptor of this category. Residual bone graft and non-bone tissue parameters were also often evaluated. With regard to dynamic histomorphometry, mineral apposition rate (MAR) was the parameter of choice for most researchers, with calcein green being the preferred dye for fluorochrome labelling. An overview of the contemporary literature, as well as weaknesses in the current research protocols have been discussed.
Graphene Supported NiFe-LDH and PbO2 Catalysts Prepared by Plasma Process for Oxygen Evolution Reaction
Authors: Yang Tingting , Zhang Zheng , Tan Fei , Liu Huayu , Li Xingyu , Wang Hongqi , Yang Qing
Published: December 2024

The development of efficient catalysts for water electrolysis is crucial for advancing the low-carbon transition and addressing the energy crisis. This work involves the fabrication of graphene-based catalysts for the oxygen evolution reaction (OER) by integrating NiFe-LDH and PbO2 onto graphene using plasma treatment. The plasma process takes only 30 min. Graphene’s two-dimensional structure increases the available reaction surface area and improves surface electron transport. Plasma treatment further improves catalyst performance by facilitating nanoparticle attachment and creating carbon defects and sulfur vacancies. Density functional theory (DFT) calculations at the PBE provide valuable insights into the role of vacancies in enhancing catalyst performance for OER. The catalyst’s conductivity and electronic structure are greatly impacted by vacancies. While modifications to the electronic structure increase the kinetics of charge transfer, the vacancy structure can produce more active sites and improve the adsorption and reactivity of OER intermediates. This optimization of intermediate adsorption and electronic properties leads to increased overall OER activity. The catalyst NiFe-PbO2/S/rGO-45, synthesized through plasma treatment, demonstrated an overpotential of 230 mV at 50 mA·cm−2 and a Tafel slope of 44.26 mV dec−1, exhibiting rapid reaction kinetics and surpassing the OER activity of commercial IrO2. With its excellent performance, the prepared catalyst has broad prospects in commercial applications such as water electrolysis and air batteries.
The Evolution of the Tensile Properties of MoS2-Coated Titanium Alloy Bolts Under the Synergistic Damage of NaCl Corrosion and Preloading
Authors: Feng Derong , Xie Maoyang , Yu Weilin , Li Chao , Guo Raolong , Hu Yunpeng , Ming Quanyuan , Wan Qiang
Published: December 2024

MoS2 coating is a newly developed method to prevent bolt corrosion and the seizure of bolts used in equipment in sea areas. It is of great significance to investigate the evolution of the tensile properties and intact coatings for the maintenance of coated bolts. To evaluate the tensile properties of MoS2-coated titanium alloy bolts, titanium alloy bolts coated with MoS2 (TC4+MoS2) and bolts treated with a composite treatment of anodizing oxidation and MoS2 coating (TC4+AO+MoS2) were corroded in salt spray tests for 4300 h. The MoS2 coating significantly enhanced the bolts’ corrosion resistance, demonstrating exceptional protective performance by only experiencing minor peeling due to oxidation-induced cracking of the coating during the extensive 4300 h salt spray test. The tensile strengths of the TC4+MoS2 and TC4+AO+MoS2 bolts both decreased as compared with the original bolts. The bolts pretreated with anodic oxidation revealed lighter coating peeling and maintained a higher tensile strength after corrosion. Therefore, it can be concluded that the coatings provided excellent corrosion resistance, leading to a minor impact on the bolts’ tensile strength and fracture behavior under the synergistic damage of sea water corrosion and preloading.
Effect of Cold Deformation on the Microstructural and Property Uniformity of Al2O3/Cu Composites
Authors: Liu Song , Li Shaolin , Song Kexing , Guo Xiuhua , Song Hao , Qi Keke , Chen Fuxiao
Published: December 2024

Copper matrix composites (Cu-MCs) have garnered significant attention due to their exceptional electrical, wear-resistant, and mechanical properties. Among them, Al2O3/Cu composites, reinforced with Al2O3, are a focal point in the field of high-strength, high-conductivity copper alloys, owing to their high strength, excellent electrical conductivity, and superior resistance to high-temperature softening. Cold deformation is an effective method for enhancing the mechanical properties of Al2O3/Cu composites. However, during cold deformation of large-cross-sectional Al2O3/Cu composites, the inhomogeneity in microstructure and properties induced by varying stress states cannot be overlooked. In this study, cold deformation of 1.12 wt% Al2O3/Cu large-cross-sectional composites was performed using a rolling process, coupled with finite element numerical simulations, to investigate the distribution characteristics of microstructure and properties during the rolling process. The results indicate that under cold deformation, the hardness of the material increases linearly from the surface layer to the core, while the change in electrical conductivity is minimal. The increase in hardness is closely related to variations in dislocation density and grain size, with dislocation density being the dominant strengthening mechanism. Quantitative analysis reveals that strain inhomogeneity during cold deformation is the primary cause of microstructural differences, leading to variations in mechanical properties at different positions. This study provides a theoretical basis for understanding the inhomogeneity of cold deformation in large-sized Al2O3/Cu composites and for controlling their microstructure–property relationships.
Research on a Low-Cost, Low-Waste Method for Surface Flatness Improvement of WAAM Components Based on Tungsten Inert Gas Arc Remelting (TIGAR)
Authors: Zhao Bo , Liu Yuanlin , Kang Qingyuan , Zhao Junjie , Ma Guangyu , Wang Jie
Published: December 2024

Wire-arc additive manufacturing (WAAM) has fully empowered the design and manufacturing of metals with its unparalleled efficiency and flexibility. However, the process has relatively poor shape control capabilities, often requiring machining post-processing. This study explores a tungsten inert gas arc remelting (TIGAR) process to improve the surface flatness of WAAM components at a low cost and significantly reduce machining waste (up to 76%), which is crucial for the sustainable development of the process. The extent of surface improvement under different remelting currents was investigated. A detailed discussion was held on the mechanism by which the remelting arc, along with its molten pool, improves surface flatness. The robustness and adaptability of the process in a rough production environment were examined. And the impact of the process on the microstructure and hardness of the additive part’s surface was examined. Through systematic and quantitative analysis, it was found that within a certain range, the improvement effect on flatness increases with the increase in remelting current; when the remelting current reaches 80 A, it can significantly reduce the maximum height difference (65%) and the standard deviation of surface height (66%), and the remelting effect is uniform and reliable. TIGAR has a flattening effect on both the protrusions and depressions of the additive part’s surface. Proper overlap of remelted passes is crucial for the improvement of surface flatness. If the spacing of remelted passes is changed or the direction of remelting is adjusted, it is necessary to ensure the width of the molten pool to achieve sufficient overlap between adjacent remelted passes.
Sustainable Infrastructure: Recycled Concrete Aggregates for Cycle Paths
Authors: Konca Piotr , Szer Iwona , Szer Jacek , Obidowski Damian , Gawin Dariusz , Wiśniewski Przemysław , Wiśniewski Bartłomiej , Jóźwik Krzysztof
Published: December 2024

The application of recycled concrete aggregates (RCAs) has become increasingly popular for different types of structures, as presented in several studies. However, depending on the type of structure and the region, RCAs might have different properties. This study aims to investigate the application of RCAs of different origins for substructure layers of the cycle paths located in Central Europe, which was not analysed previously. Recycled aggregates from an airport, road overpass, and building demolition were tested according to European standards and used to produce concretes, in which compressive strength, density, water absorption, and frost resistance were tested. After 28 days, RCA concrete had compressive strengths from 5.9 to 17.3 MPa and frost resistance ratios close to 1.0. The concrete parameters indicate that RCAs might be used for the construction of cycle path substructural layers with the appropriate class of cement and W/C ratio. To meet the requirements of EN 12390-3 to achieve class C8/10, RCA concrete with CEM II B/V 32.5 should be used with a W/C ratio of 1. To meet the requirements of D-04.05.01v02, RCA concrete with CEM II B/V 32.5 and a W/C ratio smaller than 1.50 should be used. Applying recycled RCAs in various structures helps protect natural resources by reusing materials. However, the variability in RCA properties requires testing to guarantee quality.
Theoretical and Experimental Research on the Short-Range Structure in Gallium Melts Based on the Wulff Cluster Model
Authors: Wang Chun , Hua Minghao , Wang Luyao , Wang Shenglong , Liu Jinlong , Liu Rong , Tian Xuelei , Lin Xiaohang
Published: December 2024

In this paper, the short-range ordering structures of Ga melts has been investigated using the Wulff cluster model (WCM). The structures with a Wulff shape outside and crystal symmetry inside have been derived as the equivalent system to describe the short-range-order (SRO) distribution of the Ga melts. It is observed that the simulated HTXRD patterns of the Ga WCM are in excellent agreement with the experimental data at various temperatures (523 K, 623 K, and 723 K). This agreement includes first and second peak positions, widths, and relative intensities of patterns, particularly at temperatures significantly above the melting point. A minor deviation in the second peak position has been observed at 523 K, attributed to the starting of the pre-nucleation stage. These findings demonstrate that the WCM can effectively describe the SRO structure in melt systems exhibiting a certain extent of covalency.
Melt Pool Simulation of Dual Laser Beam-Arc Hybrid Welding of Aluminum Alloy Using Finite Element Method
Authors: Jin Qing-Ye , Jung Jongwook , Cheon Jooyong , Ji Changwook , Lee Wookjin
Published: December 2024

In this study, the melt pool formation behavior of high-speed laser-arc hybrid welding of aluminum plates was simulated using finite element analysis (FEA). To evaluate the heat input efficiencies of the laser and arc, standalone laser or arc welding experiments were conducted using the same arc or laser processing parameters as those employed in hybrid welding. These experiments were also simulated using FEA to calibrate the laser and arc heat adsorption parameters. The melt pool shapes were measured from cross-sectional optical microscope (OM) images of the specimens and subsequently used to develop a thermal analysis simulation of the laser and arc welding processes. A simulation model for the laser-arc hybrid welding process was developed by combining the heat input models of the laser and arc welding processes. The FEA model successfully predicted the melt pool shapes observed in the experiments. The accuracy of the developed model was evaluated, yielding average errors in the melt pool sizes of the laser, arc, and hybrid welds of 5.43%, 6.89%, and 4.51%, respectively.
Unified Design Methodology for a Polycentric Transfemoral Knee Prosthesis Using Kinematic Synthesis
Authors: Koçak Mertcan , Gezgin Erkin
Published: December 2024

This study introduces a novel single-degree-of-freedom polycentric knee mechanism specifically designed for transfemoral prostheses to address dual challenges of stability during the stance phase and biomimetic motion during the swing phase. Leveraging analytical kinematic synthesis, the proposed mechanism integrates separate kinematic designs for each of the gait phases into a combined structure that prevents singularity issues during full knee flexion, which is a significant limitation in conventional active designs. The stance phase mechanism emphasizes stability through precise control of the instantaneous center of rotation (ICR) and weight-bearing support, while the swing phase mechanism adopts a biomimetic motion trajectory. In order to validate the proposed methodology, kinematic synthesis, numerical simulations, and visual analyses were conducted. Incorporating insights from polycentric prostheses and orthotic applications, the proposed mechanism achieves a seamless transition between two different configurations by keeping its overall mobility. Additionally, its possible compatibility with motorized actuation offers a foundation for active prosthesis systems, paving the way for adapting the advantages of polycentric prosthesis to active devices. This innovative approach offers a scientifically grounded pathway for improving transfemoral prosthetic systems, advancing both their biomechanical utility and user comfort.
Ohmic Heating Nixtamalization Modifies Maize Starch and Affects the Structural and Physicochemical Characteristics of Instant Masa Flours
Authors: Dominguez-Hernandez Elisa , Rangel-Hernandez Jorge , Morales-Sanchez Eduardo , Gaytan-Martinez Marcela
Published: December 2024

The objective of this study was to examine the changes in starch processed under various ohmic heating (OH) conditions in relation to the characteristics of nixtamalized maize. Ground and dehydrated nixtamalized doughs (masas) were analyzed. Samples were prepared using both OH and traditional nixtamalization methods for comparison. The OH process variables included cooking temperature (85 and 90 °C), heating time (0, 5, and 10 min), and voltage (120 and 130 V). Starch modifications were assessed through viscosity measurements, differential scanning calorimetry (DSC), X-ray diffraction, and scanning electron microscopy (SEM). The results showed that viscosity in OH-treated samples was influenced by both thermal conditions (time and temperature) and the electric field (at 130 V), due to gelatinization and electroporation, evidenced by starch granule damage in SEM. DSC and X-ray diffraction revealed gelatinization and a loss of crystalline structures, along with new interactions between starch components that stabilized the system and reduced peak viscosity in the OH masa flours.
Modeling the Phylogenetic Rates of Continuous Trait Evolution: An Autoregressive–Moving-Average Model Approach
Authors: Jhwueng Dwueng-Chwuan
Published: December 2024

The rates of continuous evolution plays a crucial role in understanding the pace at which species evolve. Various statistical models have been developed to estimate the rates of continuous trait evolution for a group of related species evolving along a phylogenetic tree. Existing models often assume the independence of the rate parameters; however, this assumption may not account for scenarios where the rate of continuous trait evolution correlates with its evolutionary history. We propose using the autoregressive–moving-average (ARMA) model for modeling the rate of continuous trait evolution along the tree, hypothesizing that rates between two successive generations (ancestor–descendant) are time-dependent and correlated along the tree. We denote PhyRateARMA(p,q) as a phylogenetic rate-of-continuous-trait-evolution ARMA(p,q) model in our framework. Our algorithm begins by utilizing the tree and trait data to estimate the rates on each branch, followed by implementing the ARMA process to infer the relationships between successive rates. We apply our innovation to analyze the primate body mass dataset and plant genome size dataset and test for the autoregressive effect of the rates of continuous evolution along the tree.
Adaptive Control for Multi-Agent Systems Governed by Fractional-Order Space-Varying Partial Integro-Differential Equations
Authors: Liu Zhen , Wen Yingying , Zhao Bin , Yang Chengdong
Published: December 2024

This paper investigates a class of multi-agent systems (MASs) governed by nonlinear fractional-order space-varying partial integro-differential equations (SVPIDEs), which incorporate both nonlinear state terms and integro terms. Firstly, a distributed adaptive control protocol is developed for leaderless fractional-order SVPIDE-based MASs, aiming to achieve consensus among all agents without a leader. Then, for leader-following fractional-order SVPIDE-based MASs, the protocol is extended to account for communication between the leader and follower agents, ensuring that the followers reach consensus with the leader. Finally, three examples are presented to illustrate the effectiveness of the proposed distributed adaptive control protocols.
Estimation and Model Misspecification for Recurrent Event Data with Covariates Under Measurement Errors
Authors: Alahakoon Ravinath , Zamba Gideon K. D. , Wen Xuerong Meggie , Adekpedjou Akim
Published: December 2024

For subject i, we monitor an event that can occur multiple times over a random observation window [0, τi). At each recurrence, p concomitant variables, xi, associated to the event recurrence are recorded—a subset (q≤p) of which is measured with errors. To circumvent the problem of bias and consistency associated with parameter estimation in the presence of measurement errors, we propose inference for corrected estimating equations with well-behaved roots under an additive measurement errors model. We show that estimation is essentially unbiased under the corrected profile likelihood for recurrent events, in comparison to biased estimations under a likelihood function that ignores correction. We propose methods for obtaining estimators of error variance and discuss the properties of the estimators. We further investigate the case of misspecified error models and show that the resulting estimators under misspecification converge to a value different from that of the true parameter—thereby providing a basis for bias assessment. We demonstrate the foregoing correction methods on an open-source rhDNase dataset gathered in a clinical setting.
Qualitative Analysis of a COVID-19 Mathematical Model with a Discrete Time Delay
Authors: Arenas Abraham J. , González-Parra Gilberto , Saenz Miguel Saenz
Published: December 2024

The aim of this paper is to investigate the qualitative behavior of a mathematical model of the COVID-19 pandemic. The constructed SAIRS-type mathematical model is based on nonlinear delay differential equations. The discrete-time delay is introduced in the model in order to take into account the latent stage where the individuals already have the virus but cannot yet infect others. This aspect is a crucial part of this work since other models assume exponential transition for this stage, which can be unrealistic. We study the qualitative dynamics of the model by performing global and local stability analysis. We compute the basic reproduction number R0d, which depends on the time delay and determines the stability of the two steady states. We also compare the qualitative dynamics of the delayed model with the model without time delay. For global stability, we design two suitable Lyapunov functions that show that under some scenarios the disease persists whenever R0d>1. Otherwise, the solution approaches the disease-free equilibrium point. We present a few numerical examples that support the theoretical analysis and the methodology. Finally, a discussion about the main results and future directions of research is presented.
Applications of the Kosambi–Cartan–Chern Theory to Hamiltonian Systems on a Cotangent Bundle: Linking Geometric Quantities to the Self-Similar Motions of Three Point Vortices
Authors: Hirakui Yuma , Yajima Takahiro
Published: December 2024

This study presents a differential geometric framework for Hamiltonian systems expressed in terms of first-order differential equations. For systems governed by second-order ordinary differential equations on tangent bundles, such as Euler–Lagrange systems, the stability of trajectories under perturbations is analyzed based on the eigenvalue of the deviation curvature tensor. Building upon this Jacobi stability analysis approach, four geometric quantities for Hamiltonian systems are derived considering perturbations to trajectories on a cotangent bundle. As a specific Hamiltonian system, a hydrodynamic three-point vortex system is examined, and its four geometric quantities are computed using the Hamiltonian equation. The eigenvalues of these geometric quantities are then used to classify the divergent and collapsing trajectories of point vortices. Specifically, for the divergent trajectories of vortices, the eigenvalues of the geometric quantities converge to zero over time. Conversely, for their collapsing trajectories, the eigenvalues increase with time. This result implies that at the point of vortex collapse, the system becomes geometrically unstable, with diverging trajectory perturbations.
Study on Discrete Null-Field Equation Methods for Bounded Simply Connected Domains: Better Locations of Source Nodes
Authors: Zhang Li-Ping , Li Zi-Cai , Huang Hung-Tsai , Lee Ming-Gong , Kazakov Alexander L.
Published: December 2024

The discrete null-field equation method (DNFEM) was proposed based on the null-field equation (NFE) of Green’s representation formulation, where only disk domains were discussed. However, the study of the DNFEM for bounded simply connected domains S is essential for practical applications. Since the source nodes must be located outside of a solution domain S, the first issue in computations is how to locate them. It includes two topics—Topic I: The source nodes must be located not only outside S but also outside the exterior boundary layers. The width of the exterior boundary layers is derived as O(1/N), where N is the number of unknowns in the DNFEM. Topic II: There are numerous locations for source nodes outside the exterior boundary layers. Based on the sensitivity index, several better choices of pseudo-boundaries are studied for bounded simply connected domains. The advanced study of Topics I and II needs stability and error analysis. The bounds of condition numbers (Cond) are derived for bounded simply connected domains, and they are similar to those of the method of fundamental solutions (MFS). New error bounds are also provided for bounded simply connected domains. The thorough study of determining better locations of source nodes is also valid for the MFS and the discrete boundary integral equation method (DBIEM). The development of algorithms based on the NFE lags far behind that of the traditional boundary element method (BEM). Some progress has been made by following the MFS, and reported in this paper. From the theory and computations in this paper, the DNFEM may become a competent boundary method in scientific/engineering computing.
Chemical Changes Under Heat Stress and Identification of Dendrillolactone, a New Diterpene Derivative with a Rare Rearranged Spongiane Skeleton from the Antarctic Marine Sponge Dendrilla antarctica
Authors: Prófumo Andrea , Avila Conxita , Cutignano Adele
Published: December 2024

The waters around the western Antarctic Peninsula are experiencing fast warming due to global change, being among the most affected regions on the planet. This polar area is home to a large and rich community of benthic marine invertebrates, such as sponges, tunicates, corals, and many other animals. Among the sponges, the bright yellow Dendrilla antarctica is commonly known for using secondary diterpenoids as a defensive mechanism against local potential predators. From the dichloromethane extract of sponge samples from Deception Island collected in January 2023, we isolated a novel derivative with an unusual β-lactone diterpene skeleton here named dendrillolactone (1), along with seven previously described diterpenes, including deceptionin (2), a gracilane norditerpene (3), cadlinolide C (4), a glaciolane norditerpene (5), membranolide (6), aplysulphurin (7), and tetrahydroaplysulphurine-1 (8). Here, we also report our studies on the changes in the chemical arsenal of this sponge by slow temperature increase in aquaria experiments. Despite being a species capable of inhabiting volcanically active areas, with frequent water temperature fluctuations due to the existing fumaroles, the results show that diterpenes such as deceptionin, cadlinolide C, membranolide, and tetrahydroaplysulphurin-1 seem to be susceptible to the temperature increase, resulting in a trend to higher concentrations. However, temperatures above 4 °C severely affected sponge metabolism, causing its death much earlier than expected. Further research on the roles of these natural products in D. antarctica and their relationship to the sponge’s resilience to environmental changes should help to better understand the defensive mechanisms of Antarctic marine benthos in the context of global change.
Antiviral Activity of the Marine Haptophyta Diacronema lutheri
Authors: Montuori Eleonora , Ambrosino Annalisa , Della Sala Gerardo , Ragozzino Costanza , Franci Gianluigi , Zannella Carla , De Filippis Anna , de Pascale Donatella , Galdiero Massimiliano , Lauritano Chiara
Published: December 2024

There are still several viral infections affecting a considerable number of the world’s population, causing thousands of deaths each year. There are no drugs available for most viral infections and for many not even a vaccine. The marine kingdom is characterized by a huge chemical diversity; however, there is currently on the market only one drug derived from the sea with antiviral properties, called Ara-A. In the current study, we used a solid phase extraction method (SPE) to obtain pre-purified fractions from Diacronema lutheri raw extracts. We tested both raw extracts and fractions against enveloped and non-enveloped viruses. Results showed an antiviral activity of fraction C of D. lutheri against the herpes simplex virus type 1 (HSV-1 strain SC16). Liquid chromatography coupled with untargeted high-resolution tandem mass spectrometry (LC-HRMS2) were employed to chart the metabolite distribution in all SPE fractions and pinpoint molecular families unique (or almost unique) to the bioactive fraction. Sulfoquinovosyl di- and monoacylglycerols (SQDGs and SQMGs) and di- and monogalactosyl monoacylglycerols (DGMGs and MGMGs) represent the largest groups of compounds in fraction C and they are likely responsible for the antiviral properties of this fraction.
Enzymatic Hydrolysis Systems Enhance the Efficiency and Biological Properties of Hydrolysates from Frozen Fish Processing Co-Products
Authors: Sapatinha Maria , Camacho Carolina , Pais-Costa Antónia Juliana , Fernando Ana Luísa , Marques António , Pires Carla
Published: December 2024

Co-products from the frozen fish processing industry often lead to financial losses. Therefore, it is essential to transform these co-products into profitable goods. This study explores the production of fish protein hydrolysates (FPH) from three co-products: the heads and bones of black scabbardfish (Aphanopus carbo), the carcasses of gilthead seabream (Sparus aurata), and the trimmings of Nile perch (Lates niloticus). Four enzymatic hydrolysis systems were tested: an endopeptidase (Alcalase, A), an exopeptidase (Protana, P), two-stage hydrolysis with an endopeptidase followed by an exopeptidase (A + P), and a single stage with endo- and exopeptidase (AP). The results show that combined enzymatic treatments, especially single-stage Alcalase and Protana (AP), achieved high protein yields (80%) and enhanced degrees of hydrolysis (34 to 49%), producing peptides with lower molecular weights. FPH exhibited significant antioxidant activity, in 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, with EC50 values below 5 mg/mL. Additionally, AP hydrolysates demonstrated over 60% angiotensin-converting enzyme (ACE) inhibition at 5 mg/mL, indicating potential antihypertensive applications. Antidiabetic and anti-Alzheimer activities were present, but at relatively low levels. AP hydrolysates, especially from gilthead seabream, proved to be the most promising. This study highlights the value of fish co-products as sources of functional peptides, contributing to waste reduction, and their potential applications in food, agriculture, and nutraceuticals.
Eco-Friendly Extraction of Phlorotannins from Padina pavonica: Identification Related to Purification Methods Towards Innovative Cosmetic Applications
Authors: Nour Moustapha , Stiger-Pouvreau Valérie , Guenneguez Alain , Meslet-Cladière Laurence , Cérantola Stéphane , Ali Ahmed , Simon Gaelle , Daher Abdourahman , Petek Sylvain
Published: December 2024

This study focuses on developing innovative and eco-friendly purification methods for the isolation of bioactive compounds derived from Padina pavonica, a brown abundant macroalga in Djibouti. Three distinct fractions, obtained via liquid-liquid extraction (LLE_FAE), solid-phase extraction (SPE_WE50), and flash chromatography (FC_EtOH20), were selected based on their high phenolic content and antioxidant activities. All fractions were also evaluated for their anti-ageing potential by assessing their ability to inhibit two vital skin-ageing enzymes, tyrosinase and elastase. Structural analysis by 1H-13C HMBC NMR and LC-MS revealed a selectivity of phlorotannins depending on the purification methods. The LLE_FAE fraction exhibited greater structural complexity, including compounds such as phloroglucinol, diphlorethol/difucol, fucophlorethol and bifuhalol, which likely contribute to its enhanced bioactivity compared to the fractions obtained by FC_EtOH20 and SPE_WE50, which were also active and enriched only in phloroglucinol and fucophlorethol. These findings highlight the impact of purification techniques on the selective enrichment of specific bioactive compounds and demonstrated the interest of FC or SPE in producing active phlorotannin-enriched fractions. These two purification methods hold strong potential for innovative cosmeceutical applications. Results are discussed regarding the use of P. pavonica as a promising marine resource in Djibouti to be used for the development of cosmetic industry.
A Novel Sesterterpenoid, Petrosaspongin and γ-Lactone Sesterterpenoids with Leishmanicidal Activity from Okinawan Marine Invertebrates
Authors: Jomori Takahiro , Higa Nanami , Hokama Shogo , Tyas Trianda Ayuning , Matsuura Natsuki , Ueda Yudai , Kimura Ryo , Arizono Sei , de Voogd Nicole Joy , Hayashi Yasuhiro , Yasumoto-Hirose Mina , Tanaka Junichi , Mori-Yasumoto Kanami
Published: December 2024

Leishmaniasis is a major public health problem, especially affecting vulnerable populations in tropical and subtropical regions. The disease is endemic in 90 countries, and with millions of people at risk, it is seen as one of the ten most neglected tropical diseases. Current treatments face challenges such as high toxicity, side effects, cost, and growing drug resistance. There is an urgent need for safer, affordable treatments, especially for cutaneous leishmaniasis (CL), the most common form. Marine invertebrates have long been resources for discovering bioactive compounds such as sesterterpenoids. Using bioassay-guided fractionations against cutaneous-type leishmaniasis promastigotes, we identified a novel furanosesterterpenoid, petrosaspongin from Okinawan marine sponges and a nudibranch, along with eight known sesterterpenoids, hippospongins and manoalides. The elucidated structure of petrosaspongin features a β-substituted furane ring, a tetronic acid, and a conjugated triene. The sesterterpenoids with a γ-butenolide group exhibited leishmanicidal activity against Leishmania major promastigotes, with IC50 values ranging from 0.69 to 53 μM. The structure–activity relationship and molecular docking simulation suggest that γ-lactone is a key functional group for leishmanicidal activity. These findings contribute to the ongoing search for more effective treatments against CL.
Left Ventricular Hypertrabeculation (LVHT) in Athletes: A Negligible Finding?
Authors: Jagminas Rokas , Šerpytis Rokas , Šerpytis Pranas , Glaveckaitė Sigita
Published: December 2024

Left ventricular hypertrabeculation (LVHT) used to be a rare phenotypic trait. With advances in diagnostic imaging techniques, LVHT is being recognised in an increasing number of people. The scientific data show the possibility of the overdiagnosis of this cardiomyopathy in a population of people who have very high levels of physical activity. We describe the case of a young athlete with no medical history, who presented with syncope during a marathon running race. Initial evaluation showed elevated troponin I; transthoracic echocardiography showed a trabeculated ventricle and subsequent cardiac magnetic resonance (CMR) revealed left ventricular hypertrabeculation (LVHT). During subsequent evaluation by tilt table testing, vasovagal syncope was identified as the likely aetiology of the syncope. The patient was advised to cease sports and stimulants like caffeine use. At the 29-month follow-up, CMR showed the normalisation of the non-compacted to compacted myocardial ratio and an improvement in left ventricular function, with no further syncopal episodes reported. This is an example of the physiological hypertrabeculation of the LV apex in a recreational endurance athlete, with the normalisation of the non-compacted to compacted myocardial layer ratio after detraining. Physiological hypertrabeculation, a benign component of exercise-induced cardiac remodelling, must be differentiated from non-compaction cardiomyopathy and other pathologies causing syncope. This case underscores the importance of distinguishing physiological hypertrabeculation from pathological LVHT in athletes, highlighting that exercise-induced cardiac remodelling can normalise with detraining.
Comparison of Renal Tubular Damage with Kidney Injury Molecule-1 in Open and Laparoscopic Colorectal Cancer Surgery
Authors: Duyan Abdullah Gürhan , Vatansev Celalettin , Kocabaş Rahim , Yalçın Koç Melek , Akbulut Muhammed Ali
Published: December 2024

Background and Objectives: Colorectal cancer is the third most common type of cancer in men and women. With advancements in technology, minimally invasive treatment options have become increasingly prominent in colorectal cancer surgery. This study aimed to compare the increased intra-abdominal pressure in laparoscopic colon and rectal surgery with open procedures using kidney injury molecule-1 (KIM-1) secreted from renal tubules. Materials and Methods: We enrolled 46 patients diagnosed with colon cancer who underwent laparoscopic and open surgical procedures at our clinic. The patients were prospectively randomized into five groups: 10 laparoscopic right hemicolectomies (Group 1), 8 open right hemicolectomies (Group 2), 8 laparoscopic anterior resections (LARs) (Group 3), 11 open anterior resections (Group 4), and 9 laparoscopic low anterior resections (Group 5). Urine samples were collected from the patients preoperatively, postoperatively at the 4th hour, and postoperatively on the 14th day, and the urine KIM-1 levels and urine creatinine (Cr) values were measured. The urine KIM-1/Cr ratios were subsequently calculated. Results: The urinary KIM-1/Cr levels increased at the 4th postoperative hour after the open and laparoscopic procedures. On postoperative day 14, the urinary KIM-1/Cr levels were lower than those in the preoperative period in all groups, except the LAR group. Conclusions: Our study shown that the average pressure in laparoscopic colon and rectal surgery did not have a long-term impact on kidney injury in comparison to open colon and rectal surgery.
Primary Biliary Cholangitis Associated with Ulcerative Colitis: Case Series and Literature Review
Authors: Li Qi , Zong Ye
Published: December 2024

Purpose: To study the coexistence of ulcerative colitis (UC) and primary biliary cholangitis (PBC). Methods: The Beijing Friendship Hospital patient database was explored to identify patients presenting both UC and PBC from January 2015 to July 2024. By a review of the literature, the characteristics of UC patients who experienced PBC was summarized. Results: We identified 890 UC patients and reported 4 individuals who suffered from UC and PBC. Compared to the general population, UC patients seem to have a higher risk of PBC. Only 28 cases of UC with PBC have been reported so far. Most patients were diagnosed with UC prior to PBC. Once UC patients are complicated with PBC, they might experience more than one extraintestinal manifestation (EIM). Shared susceptibility genes, certain bacterial infections, and common immune-mediated mechanisms may be involved in the pathogenesis of UC patients with PBC. Conclusions: Although the coexistence of UC and PBC is uncommon, PBC should be considered in UC patients with hepatobiliary disorders.
Standardized Mortality Ratios (SMRs) and Radon Exposure Analysis for Lung Cancer and All-Cause Mortality in Locorotondo, Southern Italy
Authors: Ferri Giovanni Maria , De Maria Luigi , Delvecchio Giuseppe , Caputi Antonio , Sole Stefano , Giannelli Gianmarco , Sifanno Gianfranco , Di Somma Ilaria Maria , Pentimone Floriana , Cavone Domenica , Stufano Angela , Lovreglio Piero , Ricci Vitantonio , Vimercati Luigi
Published: December 2024

Background and Objectives: Radon is a known risk factor for lung cancer, and residential radon exposure is the leading cause of lung cancer in never smokers; however, in Italy, there is still a lack of public awareness regarding the risk caused by residential radon exposure. In this mortality study, which was carried out in an Italian Apulian town (Locorotondo) of the Bari province, we aimed to analyze lung cancer mortality and all-cause mortality in a population highly exposed to radon. Materials and Methods: The study period was 1998–2021. Local and Italian population and national mortality data were collected from the Italian National Institute of Statistics (ISTAT) website platform. Local mortality data were collected using copies of the Local Health Authority death certificates. Results: We identified 117 lung cancers in the studied period. The mortality data trends revealed a decrease in the all-causes standardized mortality ratios (SMRs), increases in the incidence rates of lung cancer and colorectal cancer in recent years, and a decrease in the incidence of noncancer diseases. We also found high SMRs for colorectal cancer until 2016 among older females. With respect to the cardio-circulatory system, only in 2014 did the male SMRs significantly influence the total SMR; after this period, a decreasing stable trend was observed. Conclusions: The natural balance of the population is decreasing, and mortality is decreasing for all causes. A future study will be needed to assess the associations between observed lung cancer cases and domestic radon exposure to drive radon mitigation and public health strategies.
The Pharmacokinetic Changes in Cystic Fibrosis Patients Population: Narrative Review
Authors: Awaness Ayda , Elkeeb Rania , Afshari Sepehr , Atef Eman
Published: December 2024

Cystic fibrosis (CF) is a rare genetic disorder commonly affecting multiple organs such as the lungs, pancreas, liver, kidney, and intestine. Our search focuses on the pathophysiological changes that affect the drugs’ absorption, distribution, metabolism, and excretion (ADME). This review aims to identify the ADME data that compares the pharmacokinetics (PK) of different drugs in CF and healthy subjects. The published data highlight multiple factors that affect absorption, such as the bile salt precipitation and the gastrointestinal pH. Changes in CF patients’ protein binding and body composition affected the drug distribution. The paper also discusses the factors affecting metabolism and renal elimination, such as drug–protein binding and metabolizing enzyme capacity. The majority of CF patients are on multidrug therapy, which increases the risk of drug–drug interactions (DDI). This is particularly true for those receiving the newly developed transmembrane conductance regulator (CFTR), as they are at a higher risk for CYP-related DDI. Our research highlights the importance of meticulously evaluating PK variations and DDIs in drug development and the therapeutic management of CF patients.
Characteristics of Microstructure and Fracture Toughness According to the Groove Shape of Submerged Arc Welding
Authors: Shin Yong-Taek , Jung Chang-Ju , Bae Seong-Han , An Gyubaek , Son Myungrak , Park Young-Il
Published: December 2024

This study investigates the effects of heat input on the microstructure and fracture toughness of SAW (Submerged Arc Welding) joints with K-groove and X-groove weld preparations using S460NL steel. Microstructural analysis focused on acicular ferrite, grain boundary ferrite, and MA (Martensite–Austenite) constituents to assess their influence on CTOD (Crack Tip Opening Displacement). The results indicate that the K-groove achieved a higher CTOD value of 0.82 mm compared to 0.13 mm for the X-groove, attributed to differences in microstructural composition and cooling rates. The findings highlight the impact of groove geometry and heat input on weld performance.
Study on Near-Net Shape Forging of Large Marine Crank Throws
Authors: Niu Longjiang , Zhang Qingliang , Zhang Yongwan , Wang Jingyu , Luo Weiping , Liu Donghang , Ma Tengfei , Velay Xavier
Published: December 2024

The crankshaft is a critical component in large marine ships, often regarded as the “heart” of the vessel due to its role in transmitting power and motion. This article addresses the technological challenges in the forging of marine crank throws, a key segment of the crankshaft. The study employed finite element simulations to evaluate three Near-Net-Shape (NNS) forming methods: One-Step Extrusion (OSE), Upsetting/Backward Extrusion (U/BE), and Grooving–upsetting/Backward Extrusion (G–U/BE). The results show that the G–U/BE method requires the lowest load. The grooving–upsetting step in the G–U/BE process forms a rigid journal end web shape that influences the subsequent backward extrusion, with the relative groove depth (the ratio of groove depth to width) playing a crucial role in the final forging quality. Optimal crank throw formation occurs when the ratio is 1.5; deeper grooves increase the load required, diminishing the effectiveness of the grooving–upsetting step. Scaled-down experiments validate G–U/BE as a practical and feasible method for producing large marine crank throw forgings, ensuring both the desired shape and microstructural properties.