Search Results (1,926)

Attapulgite (ATP; palygorskite) is a fibrous magnesium aluminum silicate that can reinforce hydrated polymer networks, provide a surface for molecular interactions, and participate in formulation-dependent ion or drug delivery. Although ATP has been studied most extensively in bone-oriented composites, its more distinctive role in cartilage repair may be as a spatially controlled regulator of the scaffold microenvironment rather than as a uniformly distributed bioactive filler. This review therefore examines ATP from a cartilage-first perspective. Direct ATP evidence, effects of modified ATP, performance of complete drug-loaded formulations, and cross-material extrapolations are considered separately. Current cartilage data support injectability, shear-thinning, photocrosslinking, mechanical reinforcement, and sustained intra-articular delivery but do not yet establish durable hyaline cartilage regeneration. In osteochondral constructs, ATP is more plausibly restricted to the calcified-cartilage interface or subchondral region, where reinforcement and mineral-associated functions may be beneficial, while high or uniform cartilage-side loading could increase stiffness, hypertrophy, or ectopic mineralization. This interpretation leads to testable design rules: define the ATP material fingerprint, map dose and spatial distribution, distinguish the true carrier phase, and assess cartilage matrix quality, lubrication, anti-hypertrophic stability, interface mechanics, persistence, and synovial safety. ATP should thus be developed as a dose-controlled and spatially restricted component whose value depends on material–tissue matching and direct mechanistic validation. Full article

Effects of varying lanthanum (La) content on the melting characteristics, spreadability, mechanical properties of brazed joints, and microstructure of low-silver BAg5CuZn brazing filler metal were investigated. The results indicate that the addition of La has little effect on the solidus and liquidus temperatures of the filler metal, while an excessive amount of La slightly raises its liquidus temperature. An appropriate amount of La enhances the spreadability of the filler metal on both copper and stainless steel plates and simultaneously inhibits grain growth, refining the microstructure of the BAg5CuZn-xLa filler metal. When the La content in the filler metal reaches 0.3%, the shear strength of the 304 stainless steel/304 stainless steel joint brazed with BAg5CuZn-xLa filler metal reaches 492 MPa, which is 17.7% higher than that of the brazed joint without the La addition. Full article

Atmospheric carbon dioxide (CO₂) has reached an unprecedented 430 ppm, warming the planet by 50% compared with pre-industrial times and prompting a search for a quick and effective solution to control CO₂ emissions. As a robust, renewable, biodegradable, and sustainable material, nanocellulose can serve as a strong support for many active molecules. Nanocellulose, whether in suspension, aerogel, or membrane form, is not sufficient for efficient CO₂ capture and separation; hence, active molecules, such as silanes, amines, zeolites, and metal–organic frameworks (MOFs), are introduced via chemical modification, such as grafting, or via physical mixing as fillers or additives to make nanocellulose effective for CO₂ capture and separation. Introducing amine or silane molecules into nanocellulose has proven to be an effective strategy for achieving a satisfactory CO₂ absorption capacity exceeding 6 mmol/g. Nanocellulose membranes, when fabricated with MOFs or zeolites and used as a coating with polyvinyl alcohol (PVA) to create a thin-film composite membrane (TFC), can achieve CO₂ permeance of more than 600 GPU for CO₂ separation from flue gas, with CO₂/N₂ selectivity close to 40. This review provides an overview of nanocellulose-based CO₂ capture and separation materials developed over the last 10 years, along with the related challenges that must be overcome to meet current performance and demand. To facilitate readability, the author has provided a brief introduction to the origin, performance, and scale-up developments of nanocellulose at the start of this review. Full article

Rubber extrusion has evolved through overlapping advances in equip design, rheological characterization, numerical modeling, sensing, and control. This structured critical narrative review synthesizes 180 sources published from 1972 to 2026, assembled through iterative keyword searching and backward and forward citation tracing. The conventional three-zone theory of solid conveying, compression, and metering is used as a bounded analytical framework, while the literature is organized into four overlapping analytical periods spanning empirical design, constitutive and numerical modeling, engineering-scale simulation, and multiphysics and data-enabled methods. Evidence is distinguished among direct rubber-extrusion validation, rubber-material or rheological studies, transferable general polymer extrusion studies, and enabling computational, sensing, or control research. Five persistent challenges are identified: formulation-dependent nonlinear rheology; incomplete representation of filler-network evolution and wall slip; limited cross-machine and cross-formulation validation; high computational cost; and the lack of standardized datasets and reporting protocols. Digital twins, physics-informed neural networks, and neural operators are promising but remain insufficiently validated for industrial rubber extrusion. Priorities include transparent benchmark datasets, evidence-graded, uncertainty- and latency-aware validation, multimodal sensing, transferable reduced-order and learned models, and measurable sustainability indicators. Together, these priorities define a validation-oriented roadmap for more reliable, transferable, and sustainable rubber-extrusion modeling and control. Full article

Background/Objectives: Semaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA), originally developed for Type II Diabetes, has become popular for weight loss due to its ability to suppress appetite and promote fat loss. Although semaglutide’s metabolic benefits are well established, many patients have also reported unintended facial changes including facial fat atrophy, skin laxity, and an aged appearance, collectively known as “Ozempic face.” Methods: To better understand these dermatological effects, a narrative review was conducted using PubMed and Google Scholar to identify relevant peer-reviewed literature published between 2010 and 2025. Search terms included “semaglutide,” “GLP-1 receptor agonists,” “Ozempic face,” and “facial fat loss.” Peer-reviewed clinical studies, reviews, and relevant commentary were included; articles not written in English or unrelated to weight-loss aesthetic outcomes were excluded. Results: Weight loss induced by semaglutide is distinctly characterized by rapid, disproportionate depletion of sensitive facial fat compartments such as the malar, temporal, and buccal regions. Preliminary findings also suggest that GLP-1RAs may impact dermal white adipose tissue, affecting collagen production and elastin structure. Findings highlight both the biological mechanisms underlying facial aging in semaglutide users and the current lack of research-based strategies to prevent or treat these changes. Conclusions: Although aesthetic interventions such as dermal fillers and energy-based treatments may help restore volume and contour, more research is needed to characterize long-term effects and develop objective clinical guidelines. Increased counseling and awareness regarding GLP-1RA-induced facial changes should be integrated into patient care, especially as these agents continue to expand in popularity. Full article

Mass concrete structures are subjected to long-term dynamic excitations, yet traditional concrete lacks the damping needed for effective vibration control. Rubber aggregate concrete has shown promise for vibration mitigation, but how rubber particle size and replacement ratio govern damping mechanisms and thermal performance in mass concrete remains unclear. Here we study rubber aggregate concrete with two particle sizes (40-mesh and 100-mesh) at 5%, 10%, and 20% sand replacement, combining mechanical, thermal, and dynamic testing with multi-scale microstructural characterization including FTIR, MIP, and nanoindentation. The damping ratio increased by up to 110% (from 1.43% to 3.01%), the adiabatic temperature rise decreased by 32%, and the linear expansion coefficient by 88%. Three damping mechanisms were identified: rubber viscoelasticity, interfacial friction at the weak rubber–mortar interface, and pore and micro-crack energy dissipation. Finer 100-mesh rubber outperformed coarser 40-mesh at higher replacement ratios due to a micro-filler effect that refined pore structure. RC-20-100 achieved 26.6 MPa at 90 days, adequate for non-primary structural elements. We recommend 20% fine rubber as the optimal balance of high damping, thermal crack mitigation, and adequate strength for vibration-controlled mass concrete applications. Full article

This study investigates the low-temperature relaxation behavior of asphalt binders and asphalt mastics using a ductilometer-based uniaxial tensile relaxation test under a constant displacement rate. Although the low-temperature performance of SBS-modified asphalt binders has been widely studied, the relaxation mechanisms of asphalt mastics containing SBS-modified binders, particularly considering the effects of the SBS content and short-term aging, remain insufficiently understood. Polymer-modified binders were prepared from 50/70 penetration-grade bitumen blended with an industrially produced SBS copolymer concentrate containing 9% SBS. Three binders with SBS contents of 3%, 5%, and 7% were manufactured and used to prepare asphalt mastics with mineral filler. Tensile relaxation tests were performed at −12 °C on unaged and RTFOT-aged specimens. The relaxation behavior was evaluated using a modified generalized Maxwell model to describe the viscoelastic response of the materials. The novelty of this study lies in the systematic comparison of SBS-modified binders and corresponding asphalt mastics using a unified experimental and modeling approach. Unlike previous studies focused mainly on polymer-modified binders, this research extends the analysis to binder–filler systems and provides new insight into the influence of the SBS content and aging on stress relaxation mechanisms. The results demonstrate that increasing the SBS content improves the relaxation capacity of both the binders and mastics, enhancing their ability to dissipate thermally induced stresses. Moreover, a higher SBS content reduces the sensitivity of materials to short-term aging, indicating improved resistance to low-temperature cracking. Full article

Numerous previous investigations have exploited single-component aluminum hydroxide, silica, or phosphorus-containing organic agents to improve the fire resistance of epoxy resin. Existing literature confirms that ATH relies on endothermic dehydration and inorganic barrier layers to suppress combustion, while phosphorus organics exert radical quenching effects in the gas phase. However, separate use of these fillers generally requires high loading to achieve satisfactory flame retardancy, which inevitably weakens the mechanical properties of the epoxy matrix; few studies integrate N, P, and Si elements into ATH via chemical grafting to realize synergistic flame retardancy at low filler dosage, and the dual heat-transfer regulation effect of formed SiO₂-Al₂O₃ inorganic residues has rarely been systematically discussed in prior reports. This study presents an organic–inorganic hybrid flame retardant, SPDP-PTMS@ATH, synthesized by grafting N,P,Si-containing organic groups onto Al(OH)₃. The modified ATH retained its layered structure, as confirmed by FTIR, XPS, SEM, and XRD. At only 5 wt.% loading in epoxy, the additive significantly enhanced flame retardancy and smoke suppression: LOI increased to 33.5% (34% higher than pure EP), UL-94 reached V-0 rating, and peak HRR, THR, COPR, TSR, CO2PR, and SPR are reduced by 30.2%, 30.8%, 33.1%, 26.9%, 25.86%, and 15%, respectively. Char analysis revealed a denser, more graphitized structure with fewer defects. Moreover, tensile strength and elongation at break improved by 22.0% and 47.5%, respectively. This work demonstrates that low-loading SPDP-PTMS@ATH simultaneously boosts fire safety, smoke suppression, and mechanical performance, offering a cost-effective and sustainable route to high-performance epoxy composites. Full article

Current bone regeneration strategies face significant constraints, relying either on synthetic scaffolds with slow degradation that require biochemical supplements or on bioactive fillers. Recently, the focus has shifted towards functional natural biomaterials with inherent osteoinductive potential. This study presents a promising candidate based on a silica-containing plant-derived scaffold fabricated from rice straw, a sustainable resource with >20 wt.% silica. Morphological analyses revealed that the decellularised rice straw scaffold exhibits a unique surface pattern with a three-dimensional nanoarchitecture featuring parallel fibrillar protrusions and cellulosic spikes evenly distributed across the surface. Elemental mapping revealed abundant silicon, with minor traces of calcium and phosphorus, all of which are crucial components of bioactive minerals. The scaffold was highly biodegradable, with 81.7% weight loss after 90 days, attributed to its high water absorption (337%). The scaffold demonstrated excellent biocompatibility, maintaining MG63 cell viability and promoting robust adhesion and proliferation, with relative metabolic activity increasing from 105% at day 5 to 125% at day 7 relative to TCPS controls. Most remarkably, when seeded with adipose-derived human mesenchymal stem cells (hMSCs) in the absence of osteogenic medium, the scaffold induced significant biomineralisation. This osteoinductive capacity is attributed to its unique surface pattern, high roughness, and polar cellulosic substrate, together with bioactive silica that releases soluble silicon species. This work represents how agricultural waste can be upcycled for autonomous bone regeneration. Full article

The increasing demand for sustainable road infrastructure has encouraged the development of asphalt mixtures incorporating recycled materials and industrial by-products. This study developed and validated a highly circular AC14 asphalt surface mixture incorporating steel slag aggregates (SSA) and reclaimed asphalt pavement (RAP). The laboratory-designed mixture contained 63.8% SSA and 17.2% RAP, corresponding to 81.0% secondary materials, or 83.0% when recovered filler is included. Its volumetric and mechanical performance was compared with that of a conventional AC14 surface mixture with natural aggregates. The highly circular formulation was then produced in an asphalt plant and applied in a full-scale field trial. A life cycle assessment (LCA), following EN 15804:2012+A2:2019, and a production-stage cost analysis were conducted using plant-specific data. The highly circular mixture showed improved rutting resistance, higher stiffness modulus, very high resistance to water damage, and better fatigue indicators than the conventional reference mixture. The field trial supported its feasibility under real production and construction conditions. The LCA showed reductions in 12 of the 13 product-stage environmental impact indicators, including reductions of 18.1% in total global warming potential, 26.6% in abiotic depletion potential for fossil resources, 77.6% in abiotic depletion potential for minerals and metals, and 81.5% in water deprivation potential. The estimated production-stage unit price was 36.4% lower than that of the conventional mixture and 45.4% lower than the Portuguese market benchmark. These results demonstrate the technical, environmental, and economic potential of highly circular asphalt surface mixtures incorporating SSA and RAP. Full article

With the increasing use of diagnostic X-ray examinations and interventional procedures in medical institutions, the development of lead-free flexible X-ray shielding materials to reduce occupational exposure to scattered radiation has become increasingly important. Tungsten (W) is considered one of the most promising alternatives to lead (Pb) because of its high density and excellent attenuation characteristics. However, in highly filled composites, particle agglomeration and the formation of microvoids can reduce the effective density of the material, thereby limiting its shielding performance. In this study, calcined Ca–P inorganic powder derived from waste animal bone was applied as an auxiliary filler in W/PVC composite sheets to evaluate its potential for improving shielding performance through void reduction and effective density enhancement. Waste animal bone was calcined (600–1200 °C) to produce Ca–P powder. The calcined Ca–P was melt-compounded with tungsten/PVC and processed into 0.25 mm thick flexible shielding sheets. The fabricated sheets were characterized by cross-sectional scanning electron microscopy (SEM), bulk density measurements, and radiation protection efficiency (RPE) evaluations under effective X-ray energies ranging from 23.6 to 52.4 keV. SEM observations revealed a reduction in microvoids and the formation of a more continuous internal structure in the sheets containing calcined Ca–P. At the W-85 composition, the bulk density increased from 12.448 to 15.241 g/cm³, accompanied by an RPE improvement of up to 4.5 percentage points at 23.6 keV. Correspondingly, shielding performance improved by up to approximately 4.5 percentage points at 23.6 keV and by approximately 1.0–3.4 percentage points at 46.5 keV. These findings suggest that calcined Ca–P functions not as a primary shielding material replacing tungsten, but rather as a density-correcting auxiliary filler that mitigates microvoid formation and enhances the effective density of highly filled W/PVC composites. These findings demonstrate that waste animal bone-derived Ca–P is a promising upcycled densification filler for improving the processability and X-ray shielding performance of lead-free flexible shielding sheets. Full article

Additive manufacturing (AM) has expanded the design space for actuator systems by enabling complex internal geometries, multimaterial architectures, functional gradients, embedded channels, and application-specific components that are difficult to realize using conventional fabrication alone. These capabilities are particularly relevant when actuator performance is governed by the coupling between material selection, printed architecture, stimulus response, and system-level integration. This review examines additively manufactured actuators and actuator components using a material-architecture-function-integration framework. The actuator classes considered include soft pneumatic and fluidic actuators, electroactive and piezoelectric polymer actuators, shape-memory and 4D-printed actuators, magnetic and magnetoactive actuators, and printed pneumatic, hydraulic, mechanical, and aerospace-grade actuator components. Representative applications are discussed across biomedical and rehabilitation systems, aerospace and deployable mechanisms, soft robotics, and industrial automation. Beyond summarizing printed actuator demonstrations, the review analyzes the integration barriers that determine whether AM actuators can transition from laboratory prototypes to functional systems. These barriers include material durability, leakage, fatigue, dielectric breakdown, filler dispersion, interfacial failure, dimensional variability, environmental sensitivity, auxiliary hardware requirements, sensing, control, and benchmarking. By organizing recent developments across actuator classes, application domains, and integration strategies, this review clarifies where AM provides a functional advantage over conventional fabrication and where further validation is required for reliable deployment. Full article

Rigid polyurethane foams (RPUFs) are widely used as lightweight thermal insulation materials. Their properties can be improved by incorporating inorganic fillers. However, the effect of filler particle size has not been sufficiently investigated. This study examines the influence of aluminosilicate microsphere diameter (80, 150, 300, and 500 μm) on the properties of RPUFs. Foams containing 10 wt.% microspheres (M) were prepared by the free-rise method. Their cellular structure, apparent density, mechanical, acoustic, thermal, and thermomechanical properties were evaluated. The addition of microspheres reduced the average cell diameter from 184 ± 29 μm for PU_0 to 147–174 μm, depending on microsphere size, and increased the apparent density from 31.3 to approximately 37 kg·m⁻³. The compressive strength decreased from 186 ± 6 kPa for PU_0 to 159 ± 2 kPa for PU_500M, whereas the tensile strength increased from 257 ± 14 kPa for PU_0 to 323 ± 14 kPa for PU_500M. The highest average sound absorption coefficient (0.14) was obtained for PU_300M, representing a 75% improvement over PU_0 (0.08). The composites also showed improved thermal stability and storage modulus. Among the investigated composites, PU_300M exhibited the most balanced combination of mechanical and acoustic properties. Full article

Membrane distillation (MD) technology has become an effective solution to freshwater scarcity due to its low energy consumption, high separation efficiency, and ability to handle highly concentrated saline wastewater. Nevertheless, issues such as membrane wetting, membrane fouling, and low membrane flux severely limit its large-scale application. Composite membranes prepared using metal–organic framework (MOF) materials as fillers have become a research hotspot due to their advantages, such as permeable microporous channels, customizable pore structures, and modifiable active sites. These properties enable them to effectively reduce temperature polarization and concentration polarization phenomena. This article describes the characteristics of MOF materials and their current applications in the field of MD, with a comparative analysis of the applicability of MOF polycrystalline membranes and MOF composite membranes in MD, and discusses the working principle of MOFs in enhancing the performance of MD. Finally, the problems and challenges associated with the use of MOFs in MD applications are analyzed. This study aims to provide theoretical guidance for the application of MOF materials in the field of MD seawater desalination. Full article

While resin-based dental composites (RBCs) are widely recognized as the golden standard in restorative dentistry, there is a need for improvement in their properties, including their potential biofunctional behavior. The aim of this study was to assess the impact of hydroxyapatite (HA) filler on the mechanical properties and provide preliminary evidence of biofunctional potential of prepared experimental RBCs. The effects of two forms of HA filler, mHA (2.5 μm) and nHA (<200 nm), in three concentrations (2.5, 5.0, and 7.5 wt.%) were tested in regard to hardness (HV), diametral tensile strength (DTS), flexural strength (TPB), flexural modulus, and calcium and phosphate ion release. Modification with HA improves the Vickers hardness and diametral tensile strength of RBCs, but has mixed effects on the flexural strength. The tested materials meet the minimum requirements for DTS and TPB for commercial composites, but their HV is closer to flowable materials. Calcium and phosphorus are detectable on the surface of HA-modified materials via SEM-EDS. There is also preliminary evidence of calcium and phosphate ion release in materials modified with HA, with the concentrations of 5 wt.% HA and above, providing the highest levels. Full article