Materials

15 pages, 3214 KiB

Open AccessArticle

Dimensional Accuracy of Regular- and Fast-Setting Vinyl Polysiloxane Impressions Using Customized Metal and Plastic Trays—An In Vitro Study

by Moritz Waldecker, Karla Jetter, Stefan Rues, Peter Rammelsberg and Andreas Zenthöfer

Materials 2025, 18(9), 2164; https://doi.org/10.3390/ma18092164 - 7 May 2025

Viewed by 265

Abstract

The aim of this study was to compare the dimensional accuracy of vinyl polysiloxane impressions differing in terms of curing time (regular-setting (RS) or fast-setting (FS)) in combination with different tray materials (metal (M) and plastic (P)). A typodont reference model simulated a [...] Read more.

The aim of this study was to compare the dimensional accuracy of vinyl polysiloxane impressions differing in terms of curing time (regular-setting (RS) or fast-setting (FS)) in combination with different tray materials (metal (M) and plastic (P)). A typodont reference model simulated a partially edentulous maxilla. Reference points were given by center points of either precision balls welded to specific teeth or finishing-line centers of prepared teeth. These reference points enabled the detection of dimensional deviations between the digitized reference and the scans of the models achieved from the study impressions. Twenty impressions were made for each of the following four test groups: RS-M, RS-P, FS-M and FS-P. Global scan data accuracy was measured by distance and tooth axis deviations from the reference, while local accuracy was determined based on the trueness and precision of the abutment tooth surfaces. Statistical analysis was conducted using ANOVA accompanied by pairwise Tukey post hoc tests (α = 0.05). Most of the distances tended to be underestimated. Global accuracy was favorable; even for long distances, the mean absolute distance deviations were < 100 µm. Local accuracy was excellent for all test groups, with trueness ≤ 11 µm and precision ≤ 9 µm. Within the limitations of this study, all impression and tray materials were suitable to fabricate models with clinically acceptable accuracy. Full article

(This article belongs to the Special Issue Advanced Biomaterials for Dental Applications (2nd Edition))

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16 pages, 5125 KiB

Open AccessArticle

A Study on the Effect of Different Cementitious Materials on the Mechanical Properties and Microscopic Characteristics of Alkali-Activated Green Ultra-High Performance Concrete (GUHPC)

by Zhiling Liao, Wanwen Xue, Lin Liao, Ruiqing Hao, Litao Shen and Dongxia Cui

Materials 2025, 18(9), 2163; https://doi.org/10.3390/ma18092163 - 7 May 2025

Viewed by 224

Abstract

This study investigates the influence of various cementitious materials on the performance of alkali-activated green ultra-high performance concrete (GUHPC). Alkali-activated GUHPC was prepared by substituting cement, quartz powder, and limestone powder with slag powder and fly ash. The mechanical properties, durability, hydration products, [...] Read more.

This study investigates the influence of various cementitious materials on the performance of alkali-activated green ultra-high performance concrete (GUHPC). Alkali-activated GUHPC was prepared by substituting cement, quartz powder, and limestone powder with slag powder and fly ash. The mechanical properties, durability, hydration products, and microstructure were systematically analyzed. The results demonstrate that, with a cement dosage of 264 kg/m³, the alkali-activated GUHPC incorporating 40% slag powder and 28% fly ash as cement replacements exhibited superior mechanical performance, achieving compressive and tensile strengths of 165.3 MPa and 7.7 MPa, respectively, after curing. The GUHPC displayed a dense internal structure with an extremely low porosity of 6.76%, along with superior impermeability and frost resistance compared to conventional UHPC. Slag powder exhibited high pozzolanic reactivity under alkali activation, enabling effective cement replacement. These findings provide valuable insights for the formulation of alkali-activated GUHPC. Full article

(This article belongs to the Section Construction and Building Materials)

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14 pages, 6646 KiB

Open AccessArticle

Prospect of Tellurium in High-Temperature Carburizing Gear Steels: An Industrial Study

by Jin Wang, Yun Bai, Wei Liu, Huiyu Xu, Qingsong Zhang, Guangwei Wang, Shufeng Yang and Jingshe Li

Materials 2025, 18(9), 2162; https://doi.org/10.3390/ma18092162 - 7 May 2025

Viewed by 169

Abstract

This work is a continuation of our previous research. We successfully produce low-carbon gear steel containing trace tellurium (Te) through industrial production line (EAF-LF-VD-CC), and we investigate the effects of a trace Te addition on the precipitation of MnS inclusions in sulfur-containing gear [...] Read more.

This work is a continuation of our previous research. We successfully produce low-carbon gear steel containing trace tellurium (Te) through industrial production line (EAF-LF-VD-CC), and we investigate the effects of a trace Te addition on the precipitation of MnS inclusions in sulfur-containing gear steel billets, the machinability of rods, and the high-temperature vacuum carburizing performance of rods. This study demonstrates that the addition of trace Te in steel can be achieved in industrial production without causing disruptions in the steelmaking process. The Te addition effectively induces spheroidization and refinement of MnS inclusions in industrial cast billets, showing good consistency with laboratory Te alloying experimental results. Furthermore, the Te addition reduces the deformation rate of MnS inclusions during industrial rolling processes. Benefiting from the spheroidization of MnS inclusions, the chip-breaking performance during the machining of Te-containing rods is significantly optimized, along with substantial improvement in machined surface roughness. The industrial rods exhibit excellent grain stability during 960 °C high-temperature vacuum carburizing, with carburizing rates significantly enhanced compared to conventional gear steels. This work comprehensively demonstrates the multifaceted effects of Te treatment on gear steel properties, particularly providing valuable references for developing high-temperature carburizing gear steels. Full article

(This article belongs to the Special Issue Progress and Challenges of Advanced Metallic Materials and Composites)

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24 pages, 2746 KiB

Open AccessReview

Molecularly Imprinted Titanium Dioxide: Synthesis Strategies and Applications in Photocatalytic Degradation of Antibiotics from Marine Wastewater: A Review

by Xue Han, Yu Jin, Luyang Zhao, Yuying Zhang, Binqiao Ren, Xiaoxiao Song and Rui Liu

Materials 2025, 18(9), 2161; https://doi.org/10.3390/ma18092161 - 7 May 2025

Viewed by 225

Abstract

Antibiotic residues in the marine environment pose a serious threat to ecosystems and human health, and there is an urgent need to develop efficient and selective pollution control technologies. Molecular imprinting technology (MIT) provides a new idea for antibiotic pollution control with its [...] Read more.

Antibiotic residues in the marine environment pose a serious threat to ecosystems and human health, and there is an urgent need to develop efficient and selective pollution control technologies. Molecular imprinting technology (MIT) provides a new idea for antibiotic pollution control with its specific recognition and targeted removal ability. However, traditional titanium dioxide (TiO₂) photocatalysts have limited degradation efficiency and lack of selectivity for low concentrations of antibiotics. This paper reviews the preparation strategy and modification means of molecularly imprinted TiO₂ (MI-TiO₂) and its composites and systematically explores its application mechanism and performance advantages in marine antibiotic wastewater treatment. It was shown that MI-TiO₂ significantly enhanced the selective degradation efficiency of antibiotics such as tetracyclines and sulfonamides through the enrichment of target pollutants by specifically imprinted cavities, combined with the efficient generation of photocatalytic reactive oxygen species (ROS). In addition, emerging technologies such as magnetic/electric field-assisted catalysis and photothermal synergistic effect further optimized the recoverability and stability of the catalysts. This paper provides theoretical support for the practical application of MI-TiO₂ in complex marine pollution systems and looks forward to its future development in the field of environmental remediation. Full article

(This article belongs to the Section Catalytic Materials)

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25 pages, 6579 KiB

Open AccessArticle

Optimising Embodied Carbon in Axial Tension Piles: A Comparative Study of Concrete, Steel, and Timber Piles Using a Hybrid Genetic Approach

by Kareem Abushama, Will Hawkins, Loizos Pelecanos and Tim Ibell

Materials 2025, 18(9), 2160; https://doi.org/10.3390/ma18092160 - 7 May 2025

Viewed by 179

Abstract

The construction industry is a major contributor to the global climate crisis, prompting increasing interest in minimising the embodied carbon of structures, whether through material production regulations or the optimisation of structural elements. While a wide body of literature addresses the reduction of [...] Read more.

The construction industry is a major contributor to the global climate crisis, prompting increasing interest in minimising the embodied carbon of structures, whether through material production regulations or the optimisation of structural elements. While a wide body of literature addresses the reduction of embodied carbon in superstructures, limited attention has been devoted to the optimisation of foundations, particularly piles. This research introduces a hybrid genetic algorithm optimisation tool designed to minimise the embodied carbon of tension piles in different soil conditions. Six different pile types are analysed: solid and hollow concrete piles, steel pipes, universal column (UC) sections, and timber piles in both square and circular forms. The optimal design parameters for each pile type on undrained clay and loose sand are presented and compared. The results demonstrate the potential for reducing the embodied carbon of tension piles when utilising optimised designs. Finally, a case study involving an 8-metre-high cross-road signpost is presented, illustrating the practical application of the proposed optimisation algorithm for reducing embodied carbon in future designs. Full article

(This article belongs to the Special Issue Experimental Study, Numerical Simulation & Structural Applications of Construction Materials—3rd Edition)

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11 pages, 7943 KiB

Open AccessArticle

Development of Thin Carbon-Ceramic Based Coatings in Roll-to-Roll Mode: Tribological and Corrosion Results on Stainless Steel

by Mª Fe Menéndez Suárez, Pascal Sanchez, Ana L. Martínez Díez, Beatriz Mingo Roman and Marta Mohedano Sánchez

Materials 2025, 18(9), 2159; https://doi.org/10.3390/ma18092159 - 7 May 2025

Viewed by 161

Abstract

In this work, silicon oxide based coatings with embedded graphene nanoplatelets (content ranging from 1.8 wt.% to 7.2 wt.%) have been developed following the sol-gel route, using AISI430 stainless steel as substrate and dip and roll-to-roll as coating techniques. The tribological and corrosion [...] Read more.

In this work, silicon oxide based coatings with embedded graphene nanoplatelets (content ranging from 1.8 wt.% to 7.2 wt.%) have been developed following the sol-gel route, using AISI430 stainless steel as substrate and dip and roll-to-roll as coating techniques. The tribological and corrosion behaviour of these coatings have been evaluated and compared to bare steel. Concerning tribological behaviour, the coefficient of friction and wear print were significantly reduced with increasing the graphene nanoplatelets content. Regarding corrosion, all coatings showed improved corrosion behaviour compared to bare steel. However, higher concentration of nanoplatelets revealed a negative effect on the corrosion resistance, probably due to aggregation. Taking into account these two counteracting effects, as final part of this work, a bilayer coating with different graphene content has been proposed and fabricated. A top layer, with high graphene nanoplatelets concentration has allowed enhanced tribological properties whereas bottom layer, with no graphene nanoplatelets assures corrosion inhibition under harsh environments. Full article

(This article belongs to the Section Corrosion)

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13 pages, 8078 KiB

Open AccessArticle

Edgewise Compressive Properties of Ecological Sandwich Panels with Engineered Bamboo Face Sheets and Bamboo Culm Core

by Xiaoran Liu, Jingjing Deng, Mao Wang, Xinmiao Meng and Lu Xu

Materials 2025, 18(9), 2158; https://doi.org/10.3390/ma18092158 - 7 May 2025

Viewed by 123

Abstract

Bamboo is a green, renewable material with high strength and low cost, but raw bamboo has limited application in residential buildings due to its irregular shape and dry cracking. In this regard, this work proposed a novel ecological sandwich panel to explore the [...] Read more.

Bamboo is a green, renewable material with high strength and low cost, but raw bamboo has limited application in residential buildings due to its irregular shape and dry cracking. In this regard, this work proposed a novel ecological sandwich panel to explore the potential combination of engineered bamboo and raw bamboo culms. Face sheets made of glued laminated bamboo panels were bonded to the bamboo culm core via epoxy resin and mortise–tenon joints. Two groups of specimens with height-to-thickness ratios of 4.63 and 5.37 were tested through edgewise compression to investigate the failure modes, strength and rigidity. The results revealed that the specimens had no overall stability problem under axial loading, but exhibited delamination and local bulging to the face sheets. When the height-to-thickness ratio increased from 4.63 to 5.37, but still belonged to the short member range, the area of the adhesive interface increased by 16.13%, and the edgewise compressive strength and rigidity increased by 17.57% and 35.04%, respectively. This indicated that the capacity and rigidity were mainly determined by the connection strength, which was obviously affected by the manufacturing and assembly errors. Accordingly, increasing the connection strength could be helpful for improving the load-carrying capacity and ductility of such panels. Full article

(This article belongs to the Section Advanced Composites)

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18 pages, 5139 KiB

Open AccessArticle

Effects of Complex Environmental Conditions on Fatigue Self-Healing Properties of Fast-Melting SBS-Modified Asphalt

by Jinchao Yue, Jiahao Fu, Yihan Wang, Yang Ming, Guoqi Tang and Ruixia Li

Materials 2025, 18(9), 2157; https://doi.org/10.3390/ma18092157 - 7 May 2025

Viewed by 158

Abstract

Asphalt pavements are prone to various distresses under complex environmental influences during service, which significantly affects their fatigue life. This study conducted complex environmental simulation tests, including pressure aging, ultraviolet (UV) aging, and coupling effects with salt solutions at different concentrations. A dynamic [...] Read more.

Asphalt pavements are prone to various distresses under complex environmental influences during service, which significantly affects their fatigue life. This study conducted complex environmental simulation tests, including pressure aging, ultraviolet (UV) aging, and coupling effects with salt solutions at different concentrations. A dynamic shear rheometer (DSR) was employed to perform frequency sweep tests, linear amplitude sweep (LAS) tests, and fatigue–healing–fatigue tests. The fatigue self-healing properties of fast-melting SBS (SBS-T)-modified asphalt were evaluated based on the viscoelastic continuous damage theory. The results indicate that coupled aging effects significantly increase the viscoelastic characteristic parameters of SBS-T-modified asphalt, with more elastic components transforming into viscous components. Compared to other aging effects, the coupled pressure-UV-salt solution condition induces the most severe degradation in the fatigue durability of SBS-T-modified asphalt. Simultaneously, the self-healing capability of aged asphalt is also reduced. Specifically, with increasing strain, more complex aging conditions lead to the faster deterioration of asphalt fatigue life and lower self-healing capacity. While asphalt demonstrates measurable fatigue life restoration through self-healing, the synergistic coupling of salt solution exposure and multi-factor aging significantly compromises both the absolute fatigue resistance and the relative recovery efficiency. Full article

(This article belongs to the Special Issue Innovative Approaches in Asphalt Binder Modification and Performance)

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25 pages, 9079 KiB

Open AccessArticle

Plasma Modification Effects of Thermoplastic Starch (TPS) Surface Layer: Film Wettability and Sterilization

by Magdalena Stepczyńska and Aleksandra Śpionek

Materials 2025, 18(9), 2156; https://doi.org/10.3390/ma18092156 - 7 May 2025

Viewed by 152

Abstract

The effect of low-temperature plasma treatment on the surface properties of thermoplastic starch film (TPS) was investigated. The surface layer (SL) modification of polymeric materials is mainly carried out to improve wettability and adhesive properties and to increase surface cleanliness. TPS was modified [...] Read more.

The effect of low-temperature plasma treatment on the surface properties of thermoplastic starch film (TPS) was investigated. The surface layer (SL) modification of polymeric materials is mainly carried out to improve wettability and adhesive properties and to increase surface cleanliness. TPS was modified in an air atmosphere under either atmospheric or reduced pressure. The process parameters for modifying the SL of TPS were determined based on wettability assessment using a goniometer, geometric structure using scanning electron microscopy (SEM), and the degree of oxidation (O/C ratio) using X-ray photoelectron spectroscopy (XPS). Additionally, the effect of plasma treatment on TPS film sterilization was investigated. Full article

(This article belongs to the Special Issue Advances in Plasma Treatment of Materials)

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24 pages, 4182 KiB

Open AccessArticle

New Biobased Plasticizers for PVC Derived from Saturated Dimerized Fatty Acids

by Patryk Dziendzioł, Sylwia Waśkiewicz and Katarzyna Jaszcz

Materials 2025, 18(9), 2155; https://doi.org/10.3390/ma18092155 - 7 May 2025

Viewed by 205

Abstract

Phthalates are compounds widely used as very effective plasticizers of PVC. Unfortunately, they are also widely known to be endocrine disruptors and are detrimental to human health and the environment. For this reason, environmentally friendly plasticizers are being intensively sought after in response [...] Read more.

Phthalates are compounds widely used as very effective plasticizers of PVC. Unfortunately, they are also widely known to be endocrine disruptors and are detrimental to human health and the environment. For this reason, environmentally friendly plasticizers are being intensively sought after in response to the market needs in the context of sustainable development and legislative changes regarding the use of phthalates. Our research presents an innovative approach to addressing this problem. In this paper, we propose new biobased oligoesters as non-toxic and harmless plasticizers of poly(vinyl chloride). New plasticizers were obtained by polyesterification of saturated dimerized fatty acid (DFA), adipic acid (ADA), triethylene glycol (TEG), and 2-ethylhexanol (2-EH), and were characterized by nuclear magnetic resonance, size exclusion chromatography, and viscosity analyses. The compatibility of the obtained oligoesters with PVC was determined using the method for obtaining PVC films by casting from a THF solution. Selected plasticizers were used to obtain PVC blends at 50 phr. They were then tested for plasticizer migration, hardness, thermogravimetric analysis, differential scanning calorimetry, and mechanical strength. Their properties were compared with the commercially available monomeric plasticizers di(2-ethylhexyl) terephthalate and di(2-ethylhexyl) adipate. The conducted study shows that the oligoesters obtained at a molar ratio of ADA to DFA of 9:1 and using an excess of 2-EH exhibit very good compatibility and plasticizing ability. The use of higher amounts of DFA worsens the compatibility of the oligoesters with PVC. However, a 4:1 ADA-to-DFA molar ratio produced results that still allow for the use of these compounds as plasticizers at lower concentrations or in combination with other plasticizers. Full article

(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)

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17 pages, 15636 KiB

Open AccessArticle

Fabrication of Mechanically Robust Hydrophobic Surfaces Using Femtosecond Laser Shock Peening

by Chao Xu, Mengyu Jia, Yucheng Gu, Peishuo Wang, Zhen Zhang and Yulei Wang

Materials 2025, 18(9), 2154; https://doi.org/10.3390/ma18092154 - 7 May 2025

Viewed by 145

Abstract

The harsh service environment has increased the demand for hydrophobic surfaces with excellent mechanical properties; however, how to manufacture such surfaces remains a significant challenge. In this study, a method for fabricating hydrophobic surfaces with excellent mechanical properties using femtosecond laser shock peening [...] Read more.

The harsh service environment has increased the demand for hydrophobic surfaces with excellent mechanical properties; however, how to manufacture such surfaces remains a significant challenge. In this study, a method for fabricating hydrophobic surfaces with excellent mechanical properties using femtosecond laser shock peening (fs-LSP) is proposed, without the need for any additional processing steps. Taking CH1900A martensitic steel as an example, a systematic analysis of the microstructure was conducted after fs-LSP, revealing the mechanisms by which fs-LSP affects surface morphology, grain structure, dislocation density, and grain boundary characteristics. The high-density dislocations and grain refinement induced by fs-LSP significantly enhanced the surface hardness and introduced residual compressive stresses. Additionally, the laser-induced periodic micro/nanostructures on the surface ensured excellent hydrophobic properties. The effect of single pulse energy and the number of impacts on fs-LSP has also been discussed in detail. As the pulse energy and number of impacts were increased, the surface microstructure of the material was progressively optimized, evidenced by grain refinement, an increase in geometrically necessary dislocation (GND) density, and a higher proportion of high-angle grain boundaries (HAGBs). Such optimization is not monotonous or unlimited; a pulse energy of 75 μJ and six impacts achieved the optimal effect, with the surface hardness reaching up to 8.2 GPa and a contact angle of 135 degrees. The proposed fs-LSP provides a new strategy for manufacturing hydrophobic surfaces with excellent mechanical properties, and the detailed discussion and analysis also provide theoretical guidance for process optimization. Full article

(This article belongs to the Special Issue Material Surface Topography Measurement, Analysis and Characterization)

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16 pages, 9922 KiB

Open AccessArticle

Preparation and Properties of Phase Change Energy Storage Composites Based on Modified Fly Ash

by Chaoheng Li, Qingchun Yu, Yong Deng, Qixiang Su, Tianlie Xiao and Yifan Sun

Materials 2025, 18(9), 2153; https://doi.org/10.3390/ma18092153 - 7 May 2025

Viewed by 157

Abstract

Fly ash (FA) is a porous solid waste produced by coal-fired power plants that can be used as a carrier for solid–liquid phase change materials (PCM). Due to the disadvantages of FA, including small adsorption capacity and poor thermal performance, its application range [...] Read more.

Fly ash (FA) is a porous solid waste produced by coal-fired power plants that can be used as a carrier for solid–liquid phase change materials (PCM). Due to the disadvantages of FA, including small adsorption capacity and poor thermal performance, its application range is limited. Therefore, FA modification methods have received increasing attention. Two modification methods were used to improve the adsorption capacity of FA. After the modification experiments, the surface structure of modified fly ash (MFA) was eroded, revealing a three-dimensional porous structure. The Al/Si mass ratio of the alkali-modified sample increased from 0.67 to 1.28, and the specific surface area and pore volume increased from 3.82 m²/g and 0.008 cm³/g to 40.86 m²/g and 0.026 cm³/g, respectively. The shape-stable phase change material (SSPCM) prepared using the hybrid sintering method of Al-12Si alloy and alkali-modified fly ash (MFA-OH) exhibits excellent thermal properties and thermal cycling stability. The results showed that the heat storage density and thermal conductivity of SSPCM increased with an increase in PCM content. The thermal conductivity and latent heat of phase change in the composite with the highest latent heat of phase change in the sample were 18.24 W/(m·K) and 124.10 J/g, respectively. The optimum loading rate for the alloy is 65 wt%. After 100 thermal cycles, the latent heat and thermal conductivity of the phase change at SSPCM were 93.3% and 94.6% of the initial values, respectively. The research findings provide a feasible process for FA as a phase change carrier, and the application scope is extended. Full article

(This article belongs to the Section Advanced Composites)

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16 pages, 2448 KiB

Open AccessArticle

Fluoride Uptake and Surface Characteristics of Ion-Releasing Restoratives After Brushing with Fluoride Toothpastes

by Llubitza Slaviza Banic Vidal, Ivan Šalinović, Nikolina Nika Veček, Anja Ivica, Ivana Miletić and Silvana Jukić Krmek

Materials 2025, 18(9), 2152; https://doi.org/10.3390/ma18092152 - 7 May 2025

Viewed by 167

Abstract

This study aimed to evaluate the influence of different fluoride-containing toothpastes on fluoride uptake, surface roughness, and microhardness of six ion-releasing restorative dental materials, including glass hybrids (EQUIA Forte HT with and without coating), glass ionomer cements (Fuji IX), resin-modified GICs (Fuji II [...] Read more.

This study aimed to evaluate the influence of different fluoride-containing toothpastes on fluoride uptake, surface roughness, and microhardness of six ion-releasing restorative dental materials, including glass hybrids (EQUIA Forte HT with and without coating), glass ionomer cements (Fuji IX), resin-modified GICs (Fuji II LC), alkasites (Cention Forte), and ion-releasing composites (Luminos UN and Activa). Specimens were prepared and subjected to a four-day brushing protocol using six toothpastes with varying fluoride formulations (NaF, SnF2, SMFP) and concentrations. Fluoride uptake was assessed by measuring fluoride release using an ion-selective electrode, while surface roughness and microhardness were assessed before and after brushing. Results revealed significant variations in fluoride uptake, with Fuji IX and EQUIA Forte HT showing the highest release, particularly when brushed with NaF-based toothpastes (Duraphat 5000 and 2800). Surface roughness increased post-brushing, with the greatest changes observed in Activa, while microhardness decreased across most materials, except for coated EQUIA Forte HT, which exhibited improved compactness. Resin-based composites, such as Luminos UN and Activa, demonstrated lower fluoride uptake and minimal changes in microhardness compared to GICs. The findings underscore the importance of material composition and toothpaste formulation in influencing fluoride dynamics, surface properties, and mechanical performance of restorative materials. Full article

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16 pages, 6973 KiB

Open AccessArticle

Preparation of NaA Zeolite Composite Polyacrylonitrile Membranes (TiO₂-NaA@PANMs) Doped with TiO₂ and Adsorption Study of Sr²⁺

by Yu Liu, Erna Wei, Riwen Ji and Kaituo Wang

Materials 2025, 18(9), 2151; https://doi.org/10.3390/ma18092151 - 7 May 2025

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Abstract

As a rarefied metallic element, strontium (Sr) is susceptible to significant environmental radioactive contamination risks during industrial mining and refining processes. In this study, NaA molecular sieves were prepared by alkali excitation using synthetic powders, which were homogeneously blended with the polyacrylonitrile (PAN) [...] Read more.

As a rarefied metallic element, strontium (Sr) is susceptible to significant environmental radioactive contamination risks during industrial mining and refining processes. In this study, NaA molecular sieves were prepared by alkali excitation using synthetic powders, which were homogeneously blended with the polyacrylonitrile (PAN) matrix, and nanoscale TiO₂ reinforcing phases were introduced. Finally, composite separation membranes (TiO₂-NaA@PANMs) with stable adsorption properties were constructed by electrostatic spinning technology. The micro-morphology and interfacial properties were characterized by SEM, XRD, and FT-IR systems. The adsorption experiments demonstrated that the equilibrium adsorption capacity of the system for Sr²⁺ reached 55.00 mg/g at the optimized pH = 6.0, and the theoretical saturated adsorption capacity at 298 K was 80.89 mg/g. The isothermal process conformed to the Langmuir’s model of monomolecular layer adsorption, and the kinetic behavior followed the quasi-secondary kinetic equation. Following three cycles of regeneration by elution with a 0.3 mol/L sodium citrate solution, the membrane material exhibited 81.60% Sr²⁺ removal efficacy. The composite membrane passages exhibited remarkable potential for utilization in engineering applications involving the treatment of complex nuclear wastewater. Full article

(This article belongs to the Section Thin Films and Interfaces)

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25 pages, 12314 KiB

Open AccessArticle

Optimization and Analysis of Plates with a Variable Stiffness Distribution in Terms of Dynamic Properties

by Łukasz Domagalski and Izabela Kowalczyk

Materials 2025, 18(9), 2150; https://doi.org/10.3390/ma18092150 - 7 May 2025

Viewed by 183

Abstract

This study investigates the optimization of thickness distribution in simply supported and cantilever plates to maximize gaps between adjacent natural frequencies. The research employs a genetic algorithm (GA) as the primary optimization tool, with the finite element method (FEM) integrated for structural dynamics [...] Read more.

This study investigates the optimization of thickness distribution in simply supported and cantilever plates to maximize gaps between adjacent natural frequencies. The research employs a genetic algorithm (GA) as the primary optimization tool, with the finite element method (FEM) integrated for structural dynamics analysis. The optimization process focuses on tailoring the plate thickness (stiffness) while maintaining fixed overall dimensions. The study considers square and rectangular plates with two boundary conditions: simply supported and cantilever. The optimization targets gaps between the first three natural frequencies. The GA-based optimizer demonstrates effectiveness in increasing the relative separation between neighboring natural frequencies, as defined by the fitness function. Compared to the reference individuals, the optimized individuals achieve objective function values from 0.25 to 2.5 times higher. The GA optimization tool is also compared with an alternative optimization tool achieving up to 35% better results. This research contributes to the field of structural dynamics by demonstrating the potential of genetic algorithms in optimizing plate designs for enhanced vibrational characteristics. Such optimization is particularly relevant in civil engineering, where plate elements are widely used, and where controlling dynamic properties can improve serviceability and reduce the risk of resonance under operational or environmental loads. The findings have implications for various engineering applications where controlling dynamic properties of plate structures is crucial. Full article

(This article belongs to the Section Materials Simulation and Design)

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22 pages, 26736 KiB

Open AccessArticle

High-Temperature Corrosion of Different Steels in Liquid Sn-Bi-Zn Heat Transfer Alloy

by Qingmeng Wang, Xiuli Wang, Xiaomin Cheng, Qianju Cheng and Yi Yang

Materials 2025, 18(9), 2149; https://doi.org/10.3390/ma18092149 - 7 May 2025

Viewed by 114

Abstract

In the fields of nuclear engineering and solar thermal utilization, low melting point alloys with excellent thermal conductivity and heat transfer performance have attracted extensive research as a new generation of heat transfer fluids, leading to many fundamental and important application issues. This [...] Read more.

In the fields of nuclear engineering and solar thermal utilization, low melting point alloys with excellent thermal conductivity and heat transfer performance have attracted extensive research as a new generation of heat transfer fluids, leading to many fundamental and important application issues. This study investigates the high-temperature corrosion behavior of Sn-50Bi-2Zn (wt.%) heat transfer alloy against 304 stainless steel (304), 310S heat-resistant steel (310S), and 20 carbon steel (20C) at 600 °C. Theoretical analysis, based on Fick’s diffusion law, and experimental measurements reveal significant differences in corrosion severity. After 473 h, 20 carbon steel exhibited the lowest corrosion layer thickness (0.07 mm), while 310S suffered the most severe corrosion (1.50 mm), exceeding 304SS (0.83 mm) by 81%. Diffusion coefficients derived from Sn penetration depths further quantified these trends: D310S = 2.51 × 10⁻⁷ mm²/s (6.8 × higher than 304: 3.7 × 10⁻⁸ mm²/s) and D20C = 2.87 × 10⁻¹⁰ mm²/s (128 × lower than 304SS). XRF analysis confirmed the dissolution of steel components into the molten alloy, with Fe, Cr, and Ni content increasing to 0.382 wt.%, 0.417 wt.%, and 0.694 wt.%, respectively, after 480 h. These results underscore the critical role of Ni content in accelerating Sn/Zn diffusion and pore formation, providing actionable insights for material selection in high-temperature heat transfer systems. Full article

(This article belongs to the Section Metals and Alloys)

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21 pages, 7299 KiB

Open AccessArticle

Methodological Aspects of Welded Joint Quality Assessment

by Łukasz Muślewski and Michał Pająk

Materials 2025, 18(9), 2148; https://doi.org/10.3390/ma18092148 - 7 May 2025

Viewed by 114

Abstract

The quality of manufacturing processes largely depends on applying modern design methods and technologies. Much progress has been made in the field of metallurgy and the physics of welding, including the weld pool hydrodynamics, the surface and volumetric forces of different origins, the [...] Read more.

The quality of manufacturing processes largely depends on applying modern design methods and technologies. Much progress has been made in the field of metallurgy and the physics of welding, including the weld pool hydrodynamics, the surface and volumetric forces of different origins, the modeling of the SP crystallization process, and the structural transformation morphology in SWC. Additionally, attempts have been made to use the normalized parameters of fracture mechanics to evaluate the material SU. The above-mentioned solutions have also been given a more specific character by establishing SINTAP procedures and computational welding mechanics (CWM). This study discusses a universal method for welded joint evaluation according to the most significant criteria and relevant descriptive features. Full article

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10 pages, 3871 KiB

Open AccessArticle

Effect of the Addition of Al-5Ti-0.25C and Annealing on the Mechanical Properties of Open-Cell Al Foams

by Omar Novelo-Peralta, Manuel Farid Azamar, Julio Esteban Méndez Durán, Yessica Lizbeth Ávila, Antonio Enrique Salas Reyes, Ramiro Bazáez, Ignacio Alejandro Figueroa and Gabriel Ángel Lara Rodríguez

Materials 2025, 18(9), 2147; https://doi.org/10.3390/ma18092147 - 7 May 2025

Viewed by 145

Abstract

Commercially pure aluminum (Al) was refined through the addition of the Al-5Ti-0.25C master alloy, resulting in the formation of Al₃Ti and TiC phases, which serve as refining agents. Open-cell metallic foams were successfully produced using the replication casting technique, with pore [...] Read more.

Commercially pure aluminum (Al) was refined through the addition of the Al-5Ti-0.25C master alloy, resulting in the formation of Al₃Ti and TiC phases, which serve as refining agents. Open-cell metallic foams were successfully produced using the replication casting technique, with pore sizes ranging from 1.00 to 3.35 mm. For the infiltration process, refined aluminum was used, while unrefined aluminum served as a baseline reference. The resultant foams underwent multiple annealing cycles at 480 °C, with the most refined and homogeneous microstructure observed after 504 h. Comprehensive microstructural characterization was conducted utilizing scanning electron microscopy and optical microscopy. Additionally, uniaxial compression tests were performed to generate stress–strain profiles for the foams, facilitating an assessment of their energy absorption capacity. The findings indicated an enhancement in energy absorption capacity by a factor of 2.4 to 3, which can be attributed to the incorporation of Al-5Ti-0.25C and the subsequent annealing process. Full article

(This article belongs to the Special Issue Welding, Joining, and Additive Manufacturing of Metals and Alloys (Second Edition))

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16 pages, 6361 KiB

Open AccessArticle

Storage Conditions of Textile Dosimeters for 2D UV Dose Measurements

by Elżbieta Sąsiadek-Andrzejczak, Piotr Maras and Marek Kozicki

Materials 2025, 18(9), 2146; https://doi.org/10.3390/ma18092146 - 7 May 2025

Viewed by 126

Abstract

This paper presents the optimization of storage conditions for textile dosimeters for ultraviolet radiation measurements, which are based on cotton-woven fabric and nitroblue tetrazolium chloride (NBT) as a radiation-sensitive compound. The results of changes in light reflectance and color coordinates depending on the [...] Read more.

This paper presents the optimization of storage conditions for textile dosimeters for ultraviolet radiation measurements, which are based on cotton-woven fabric and nitroblue tetrazolium chloride (NBT) as a radiation-sensitive compound. The results of changes in light reflectance and color coordinates depending on the storage time of the samples over six months from their manufacturing under various storage conditions are presented. The results obtained for cotton—NBT dosimeters, unirradiated and irradiated with a UVC dose of 100 mJ/cm², stored under the following conditions were compared: (i) at room temperature (23–25 °C, humidity 40–60%), without access to light; (ii) in a fridge (3–5 °C, humidity 70–90%), without access to light; (iii) in a freezer (−17 to −20 °C, humidity 80–90%), without access to light; and (iv) at room temperature (23–25 °C, humidity 40–60%), with access to light. Additionally, it was presented that the cotton–NBT dosimeters were suitable for 2D measurement of UV radiation doses after a period of eight months. The obtained results complement previous studies on cotton–NBT textile dosimeters and are crucial for determining the conditions of use and the expiry date of such systems. Full article

(This article belongs to the Section Smart Materials)

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12 pages, 5852 KiB

Open AccessArticle

Influence of Gel-Type Confinement for Laser Shock Peening of a Ni-Based Alloy

by Sebastian Balos, Milan Pecanac, Dragan Rajnovic, Petar Janjatovic, Miroslav Dramicanin, Sanja Kojic, Filip Cap, Lidija Krstanovic and Sanin Zulic

Materials 2025, 18(9), 2145; https://doi.org/10.3390/ma18092145 - 6 May 2025

Viewed by 227

Abstract

Laser shock peening (LSP) significantly enhances fatigue and corrosion resistance, especially in additively manufactured components. This effect is stronger when confinement is used; typically, it is water. However, water poses risks to sensitive electronics. As an alternative, this study explored gel-based confinement. A [...] Read more.

Laser shock peening (LSP) significantly enhances fatigue and corrosion resistance, especially in additively manufactured components. This effect is stronger when confinement is used; typically, it is water. However, water poses risks to sensitive electronics. As an alternative, this study explored gel-based confinement. A Ni-based alloy was LSP-treated using 532 nm and 1064 nm wavelengths, with three types of gel compared to water as a control. The results showed that gel confinement can induce compressive residual stresses and increase surface microhardness. However, gels were generally less effective than water in terms of residual stress magnitude and depth of hardening. Additionally, gel confinement required the use of a 1064 nm laser, whereas water confinement was more effective with 532 nm. Among the gels tested, one adhesive variant performed best due to improved surface contact and strong adhesion. The observed increase in microhardness and compressive stress was linked to surface grain refinement and twinning. Overall, adhesive gels offer potential benefits for LSP, particularly for additively manufactured parts, which often have high surface roughness and require non-conductive confinement solutions. Full article

(This article belongs to the Special Issue Current and Future Trends in Additive Manufacturing)

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15 pages, 3700 KiB

Open AccessArticle

Material–Structural Synergy in Ultra-High-Performance Concrete-Optimized Prestressed Concrete Cylinder Pipes: Achieving Lightweight Design for Sustainable Infrastructure

by Yunfei Xie, Chenyang Yuan, Yajun Lv, Weifeng Bai and Yizhen Zhang

Materials 2025, 18(9), 2144; https://doi.org/10.3390/ma18092144 - 6 May 2025

Viewed by 262

Abstract

While a large diameter is critical for maintaining water delivery efficiency in prestressed concrete cylinder pipes (PCCPs), excessive weight fundamentally limits their practical application. This study proposes a weight reduction strategy through material optimization and structural redesign. A full-scale experimental model of 2.8 [...] Read more.

While a large diameter is critical for maintaining water delivery efficiency in prestressed concrete cylinder pipes (PCCPs), excessive weight fundamentally limits their practical application. This study proposes a weight reduction strategy through material optimization and structural redesign. A full-scale experimental model of 2.8 m inner diameter PCCP was used to validate the finite element analysis method. Comparative numerical models were established to analyze strain/stress distribution in mortar coatings when using ultra-high-performance concrete (UHPC) versus conventional concrete cores. The key findings reveal that UHPC implementation reduces maximum coating strain by 20–30% compared to its conventional concrete counterparts. Multivariate linear regression analysis yielded a predictive formula that explicitly correlates the elastic modulus of the concrete core, core thickness, and mortar stress. This relationship permits the direct optimization of core thickness reductions according to the elastic modulus characteristics of UHPC materials. Verification through two case studies demonstrated a 25–35% core thickness reduction compared to the Chinese standard specifications while maintaining structural integrity, corresponding to an 18–22% total weight reduction. The proposed methodology successfully resolves the inherent weight limitation of conventional PCCPs while achieving equivalent hydraulic capacity, providing an effective pathway for sustainable infrastructure development through material-efficient design. Full article

(This article belongs to the Section Construction and Building Materials)

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13 pages, 8571 KiB

Open AccessArticle

Research on the Mechanical Properties and Microstructural Evolution of Al-Si Alloy for Automotive Rear Floors Based on Simulation-Assisted Casting

by Liang Gao, Qiang Wang, Qin Yang, Wenjun Liu, Bin Jiang, Yongrui Qin, Haoming Chen and Sha Lan

Materials 2025, 18(9), 2143; https://doi.org/10.3390/ma18092143 - 6 May 2025

Viewed by 195

Abstract

Al-Si alloys are essential in manufacturing automotive body structural components due to their superior casting properties, high specific strength, and excellent corrosion resistance. The microstructural evolution and mechanical properties of Al-Si alloy used in rear floors were systematically investigated based on a casting [...] Read more.

Al-Si alloys are essential in manufacturing automotive body structural components due to their superior casting properties, high specific strength, and excellent corrosion resistance. The microstructural evolution and mechanical properties of Al-Si alloy used in rear floors were systematically investigated based on a casting simulation. The results indicate that the alloy microstructure consists of α-Al, an Al-Si eutectic, and the Al₁₅(Mn,Fe)₃Si₂ intermetallic phases. The accumulation of Al₁₅(Mn, Fe)₃Si₂ intermetallic compounds increases toward the end of the filling process, leading to a reduction in mechanical properties. The optimal filling distance of the alloy ranges from 210 mm to 450 mm, while the optimal thickness ranges from 3.36 mm to 4.14 mm. With a filling distance and thickness increase, the yield strength, tensile strength, and elongation of the alloy initially increase and then decrease. The optimal properties are achieved when the filling distance is 210 mm and the thickness is 4.14 mm, with a yield strength of 122.35 MPa, a tensile strength of 258.43 MPa, and an elongation of 11.60%. At the same filling distance, near the gate position, when the thickness increases from 4.1 mm to 5.3 mm, the alloy’s tensile strength and elongation decrease. However, at positions farther from the gate, when the thickness increases from 2.94 mm to 4.93 mm, both the tensile strength and elongation of the alloy increase. This study provides a theoretical basis for the process design of large integrated die-casting components for new energy vehicles and supports the development of a high-strength ductile Al-Si alloy material system. Full article

(This article belongs to the Section Materials Simulation and Design)

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18 pages, 2822 KiB

Open AccessArticle

Iron Oxide Magnetic Nanoparticles Synthesized by Laser Target Evaporation Method for the Needs of Cancer Immunotherapy

by Felix Blyakhman, Fedor Fadeyev, Alexander Safronov, Tatiana Terziyan, Ekaterina Burban, Tatyana Shklyar and Galina Kurlyandskaya

Materials 2025, 18(9), 2142; https://doi.org/10.3390/ma18092142 - 6 May 2025

Viewed by 215

Abstract

Administration of monocyte-derived dendritic cells (moDCs) sensitized by cancer-associated antigens to the patient is applied to boost the T-cell mediated anti-tumor immune response. Loading moDCs with magnetic nanoparticles (MNPs) and controlling their migration to lymph nodes by an external magnetic field is a [...] Read more.

Administration of monocyte-derived dendritic cells (moDCs) sensitized by cancer-associated antigens to the patient is applied to boost the T-cell mediated anti-tumor immune response. Loading moDCs with magnetic nanoparticles (MNPs) and controlling their migration to lymph nodes by an external magnetic field is a way to improve the effectiveness of immunotherapy. In this study, spherical MNPs of maghemite iron oxide with a diameter of about 14 nm were synthesized by laser target evaporation method (LTE) and examined in the context of their prospective use for the needs of moDCs immunotherapy. Characterization of the physicochemical properties of MNPs and their stabilization in physiological media, as well as the magnetic properties of MNPs in the suspensions were considered in detail. The cytotoxic effect of MNPs in growth medium on the human moDCs and MNPs uptake by the cells were also estimated. We show that up-taken MNPs and MNPs in growth medium demonstrated cytotoxic effect only at high concentrations. At the same time, at low concentrations MNPs up-taken by moDCs increased their viability causing the stimulation effect. The evaluation of the quantity of MNPs, up-taken by cells, is possible by magnetometry even for the smallest γ-Fe₂O₃ concentrations. Full article

(This article belongs to the Special Issue Magnetic Nanomaterials: Synthesis, Characterization and Applications)

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20 pages, 3561 KiB

Open AccessArticle

Effect of Ti6Al4V Alloy Surface and Porosity on Bone Osseointegration: In Vivo Pilot Study in Rabbits

by Amparo Vanaclocha, Vicente Vanaclocha, Carlos M. Atienza, Pablo Jordá-Gómez, Víctor Primo-Capella, Jose R. Blasco, Luis Portolés, Nieves Saiz-Sapena and Leyre Vanaclocha

Materials 2025, 18(9), 2141; https://doi.org/10.3390/ma18092141 - 6 May 2025

Viewed by 209

Abstract

Unmodified Ti6Al4V can osseointegrate, but sometimes this capacity needs to be improved. This study aimed to see how much porosity improves osseointegration in a Ti6Al4V implant. Three types of Ti6Al4V cylindrical-shaped implants (13.00 mm length × 5.00 mm diameter) were evaluated: solid sandblasted [...] Read more.

Unmodified Ti6Al4V can osseointegrate, but sometimes this capacity needs to be improved. This study aimed to see how much porosity improves osseointegration in a Ti6Al4V implant. Three types of Ti6Al4V cylindrical-shaped implants (13.00 mm length × 5.00 mm diameter) were evaluated: solid sandblasted acid-etched, sintered, and porous 3D-printed (681.00 µm average pore size). Fifteen 20-week-old nullipara female parasite-free New Zealand California white rabbits were used, employing the femoral condyle defect model and undertaking µ-CT analysis and pull-out testing eight weeks later. On µ-CT densitometric analysis, the solid sandblasted rod showed the highest new bone growth around the implant. Bone growth was higher inside the implants for the porous 3D-printed (54.00 ± 5.00 mm³) than for the sintered (1.00 ± 0.05 mm³) and zero for the sandblasted implants. In the pull-out test, there were no statistically significant differences in the ANOVA analysis between the sintered (900.00 N ± 310.00 N) and porous 3D-printed (700.00 N ± 220.00 N) implants. Such differences did exist between the sandblasted material (220.00 N ± 50.00 N) and the two other materials (sintered p 0.002, porous p 0.034). The porous 3D-printed and sintered implant pull-out strength were significantly better than that of the solid rod sandblasted implant. Still, there were no statistically significant differences between the first two. Full article

(This article belongs to the Section Biomaterials)

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12 pages, 2540 KiB

Open AccessArticle

Monolithic GaN-Based Dual-Quantum-Well LEDs with Size-Controlled Color-Tunable White-Light Emission

by Seung Hun Lee, Dabin Jeon, Gun-Woo Lee and Sung-Nam Lee

Materials 2025, 18(9), 2140; https://doi.org/10.3390/ma18092140 - 6 May 2025

Viewed by 146

Abstract

We report a monolithic GaN-based light-emitting diode (LED) platform capable of color-tunable white-light emission via LED size scaling. By varying the LED size from 800 µm to 50 µm, the injection current density was effectively controlled under constant driving current, enabling precise modulation [...] Read more.

We report a monolithic GaN-based light-emitting diode (LED) platform capable of color-tunable white-light emission via LED size scaling. By varying the LED size from 800 µm to 50 µm, the injection current density was effectively controlled under constant driving current, enabling precise modulation of carrier distribution within a dual-composition multi-quantum well (MQW) structure. The active layer consists of five lower In_0.15Ga_0.85N/GaN QWs for blue emission and strain induction, and an upper In_0.3Ga_0.7N/GaN single QW engineered for red-orange emission. The strain imposed by lower QWs promotes indium segregation in the last QW through spinodal decomposition, resulting in a broadened emission spanning from ~500 nm to 580 nm. High-resolution TEM and EDX analyses directly confirmed the indium segregation and phase-separated structure of the last QW. Spectral analysis revealed that larger devices exhibited dominant emission at 580 nm with a correlated color temperature (CCT) of 2536 K and a CIE coordinate of (0.501, 0.490). As LED size decreased, increased hole injection allowed recombination to occur in deeper QWs, resulting in a blueshift to 450 nm and a CCT of 9425 K with CIE (0.224, 0.218) in the 50 × 50 µm² LED. This approach enables phosphor-free white-light generation with tunable color temperatures and chromaticities using a single wafer, offering a promising strategy for compact, adaptive solid-state lighting applications. Full article

(This article belongs to the Special Issue Advances in Nanophotonic Materials, Devices, and Applications)

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23 pages, 4075 KiB

Open AccessArticle

CD44 Receptor-Mediated Ferroptosis Induction by Hyaluronic Acid Carbon Quantum Dots in Triple-Negative Breast Cancer Cells Through Downregulation of SLC7A11 Pathway

by Karthikeyan Chandrasekaran, Chae Eun Lee, Seojeong Yun, Ashok Kumar Jangid, Sungjun Kim and Kyobum Kim

Materials 2025, 18(9), 2139; https://doi.org/10.3390/ma18092139 - 6 May 2025

Viewed by 292

Abstract

The field of cancer therapy is actively pursuing highly effective self-targeted drug delivery materials endowed with exceptional properties. Recently, hyaluronic acid (HA), a naturally occurring polysaccharide, has been recognized as a potential target ligand for CD44 receptors, which are frequently expressed on various [...] Read more.

The field of cancer therapy is actively pursuing highly effective self-targeted drug delivery materials endowed with exceptional properties. Recently, hyaluronic acid (HA), a naturally occurring polysaccharide, has been recognized as a potential target ligand for CD44 receptors, which are frequently expressed on various solid tumor cells targeted in cancer therapy. HA carbon quantum dots (CQDs) exhibit several advantageous properties, including a high surface area-to-volume ratio, small particle size, biocompatibility, and low cytotoxicity, making them ideal for biomedical applications, such as CD44-targeted drug delivery in ferroptosis-based cancer therapy. In this study, we synthesized HA-CQDs to enhance CD44-mediated ligand–receptor interactions targeting triple-negative breast cancer (TNBC). CQDs facilitate the intracellular generation of reactive oxygen species (ROS), leading to glutathione depletion. These processes result in crucial actions such as the downregulation of glutathione peroxidase 4, downregulation of solute carrier family 7 member 11, and inhibition of cystine intake. The subsequent intracellular ROS, originating from lipid peroxidation, induces ferroptosis. Our HA-CQDs engage CD44 receptors, selectively targeting TNBCs and enhancing cancer recognition. This interaction potentially enhances the nanoplatform-based CD44 targeted therapeutic effects in inducing ferroptosis. Full article

(This article belongs to the Special Issue Functional Polymers for Energy, Biomedical and Electrical Applications)

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15 pages, 16074 KiB

Open AccessArticle

Design on Power Factor Correction of a Digital Soft Switching Single-Phase Arc Welding Power Source

by Xiaoqing Lv and Minhao Jiang

Materials 2025, 18(9), 2138; https://doi.org/10.3390/ma18092138 - 6 May 2025

Viewed by 171

Abstract

A power factor correction circuit for a single-phase arc welding power source using digital soft switching technology is proposed. The overall hardware structure of the system, the topology principle of the selected soft switch boost circuit, and the software design approach are discussed. [...] Read more.

A power factor correction circuit for a single-phase arc welding power source using digital soft switching technology is proposed. The overall hardware structure of the system, the topology principle of the selected soft switch boost circuit, and the software design approach are discussed. The power factor correction results of the soft switch are verified under two conditions: electronic load and TIG arc welding. By using the electrical signals of the resonating capacitor and switching tube, it is confirmed that the circuit successfully achieved zero current conduction and zero voltage turn off. Through testing the power factor and efficiency of electronic loads at different powers, it was confirmed that the power factor can reach 0.985 or above, and the overall efficiency has been improved. Through TIG arc welding experiments under different welding currents, the corrected electrical signals are analyzed to verify the effectiveness of power factor correction for single-phase arc welding power. Full article

(This article belongs to the Section Metals and Alloys)

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20 pages, 3719 KiB

Open AccessArticle

Effect of Pulpal Base, Restorative Material, and Preparation Type on Marginal and Internal Fit and Fracture Strength of Endocrowns

by Kerem Yılmaz, Hakan Aydın, Fehmi Gönüldaş, Sukan Kara, Özge Çiloğlu, Erdem Özdemir and Zeynep Bilen

Materials 2025, 18(9), 2137; https://doi.org/10.3390/ma18092137 - 6 May 2025

Viewed by 227

Abstract

The aim of this innovative study was to investigate the feasibility of a modified butt joint preparation with two grooves instead of a ferrule when root dentin tissue is limited in mandibular molars. It was also investigated to what extent the effect of [...] Read more.

The aim of this innovative study was to investigate the feasibility of a modified butt joint preparation with two grooves instead of a ferrule when root dentin tissue is limited in mandibular molars. It was also investigated to what extent the effect of these treatment options on marginal and internal fit and fracture strength (FS) varied according to the type of material and whether or not a fiber ribbon was used at the base. Marginal and internal fit were evaluated using the triple-scan protocol. Statistical analysis was conducted via a three-way analysis of variance (ANOVA). The absolute marginal discrepancy (AMD), marginal discrepancy, and overall fit values for the ceramic group were 127 μm, 108 μm, and 120 μm, respectively, while corresponding values for the hybrid ceramic group were 139 μm, 116 μm, and 130 μm (p < 0.05). The mean FS recorded for ceramic restorations was 662 N, whereas hybrid ceramic restorations demonstrated a significantly higher FS of 903 N (p < 0.001). When material type was assessed independently of preparation design and base configuration, both ceramic and hybrid ceramic exceeded the predefined clinical acceptability threshold for AMD; however, they remained within acceptable limits for the remaining parameters. Among the evaluated configurations, hybrid ceramic restorations incorporating ferrules and fiber-reinforced bases exhibited the highest FS values, whereas ceramic restorations with modified biological widths and lacking fiber reinforcement yielded the lowest FS values. Full article

(This article belongs to the Section Biomaterials)

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20 pages, 4919 KiB

Open AccessArticle

Analytical and Finite Element Solution for Functionally Graded Pressure Vessels Subjected to Finite Strain Coupled Axial and Torsional Deformations

by Mohammad Shojaeifard, Arash Valiollahi, Davood Rahmatabadi, Ali Taheri, Eunsoo Choi, Alireza Ostadrahimi and Mostafa Baghani

Materials 2025, 18(9), 2136; https://doi.org/10.3390/ma18092136 - 6 May 2025

Viewed by 232

Abstract

This study presents an analytical solution to examine the mechanical behavior of an incompressible, functionally graded hyperelastic cylinder under combined extension and torsion. The exp-exp strain energy density function characterizes the hyperelastic material, with parameters varying exponentially along the radial direction. To validate [...] Read more.

This study presents an analytical solution to examine the mechanical behavior of an incompressible, functionally graded hyperelastic cylinder under combined extension and torsion. The exp-exp strain energy density function characterizes the hyperelastic material, with parameters varying exponentially along the radial direction. To validate the solution, finite element simulations using a custom UHYPER in ABAQUS are performed. The analytical and numerical results show strong agreement across different stretch and twist levels. The stress distribution and maximum stress are significantly influenced by the exponential parameter governing material gradients. Unlike axial stretch, torsion induces a more intricate longitudinal stress distribution, with large twisting producing two extrema that shift toward the cylinder’s center and outer surface. Longitudinal stress primarily governs von Mises stress and strain energy density variations across the radial direction. A critical axial stretch is identified, below which torsion-induced axial force transitions to compression, elongating the cylinder during twisting. Beyond this stretch, the axial force shifts from tensile to compressive with increasing twist, causing initial shortening before further elongation. Full article

(This article belongs to the Special Issue Modelling of Deformation Characteristics of Materials or Structures)

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25 pages, 6263 KiB

Open AccessArticle

Analysis of Late Antique and Medieval Glass from Koper (Capodistria, SI): Insights into Glass Consumption and Production at the Turn of the First Millennium CE

by Žiga Šmit and Tina Milavec

Materials 2025, 18(9), 2135; https://doi.org/10.3390/ma18092135 - 6 May 2025

Viewed by 266

Abstract

A series (n = 22) of glasses from the site Kapucinski vrt (garden of the Capuchin monastery, 5th–17th c. CE) in Koper (Capodistria), a port town in the northern Adriatic, was measured using a combined PIXE and PIGE method. Koper has been [...] Read more.

A series (n = 22) of glasses from the site Kapucinski vrt (garden of the Capuchin monastery, 5th–17th c. CE) in Koper (Capodistria), a port town in the northern Adriatic, was measured using a combined PIXE and PIGE method. Koper has been continuously populated since the late Roman period, with a rich medieval history, thus offering an opportunity to study Early Medieval glass. Stemmed goblet fragments, in the original publication dated between the 6th–9th centuries CE, and several other vessel types (beakers and flasks or bottles and lamps) were selected for analysis. The measurements were expected to show the trends in glass production and consumption from Late Antiquity until the Middle Ages, notably the transition between natron to plant ash glass and the supply of fresh glass. Among the set of 22 glass vessel fragments, both natron and plant ash glass were identified. For finer classification, we relied on a newly developed method of Euclidean distances with respect to major concentrations. Natron glass of the types Foy 2.1 (9 examples), Magby (2 examples), and Levantine I (Apollonia; 2 examples) was found. Two glasses remain undetermined but testify to an Egyptian origin. Most natron glasses show signs of recycling. Among the three unrecycled glasses (about 20% of the whole set), there are two examples of Levantine glass and a Magby glass lamp; this may indicate a modest supply of fresh glass during the period. Plant ash glass may be attributed to the Early or High Middle Ages, exploiting the purified alkalis of the Levantine coasts (known as alume catino in later Venetian glassmaking), and the admixture of impurities in the siliceous sands suggests the circulation and consumption of glass that was produced and traded in the eastern Mediterranean since the 10th century CE. Full article

(This article belongs to the Special Issue Materials in Cultural Heritage: Analysis, Testing, and Preservation)

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Materials, Volume 18, Issue 9 (May-1 2025) – 274 articles

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