Search Results (53)

This study investigates the effect of polymer film lamination on the tensile performance of wood fiber-reinforced polypropylene (WP) composites. Neat polypropylene (PP) and WP containing 25 wt% wood fiber were injection-molded and laminated with 0.1 mm PP or polyethylene terephthalate (PET) films using a compatible adhesive. Four configurations were examined: unlaminated (0S), single-sided half-length (1S-H), single-sided full-length (1S-F), and double-sided full-length (2S-F). Mechanical properties and fracture morphology were characterized by uniaxial tensile tests and scanning electron microscopy (SEM), alongside measurements of surface roughness. PET lamination produced the greatest strength enhancements, with 2S-F specimens achieving gains of 12% for PP and 21% for WP, whereas PP lamination gave minimal or negative effects, except for a 5% increase in WP. Strength improvements were attributed to surface smoothing and suppression of crack initiation, as confirmed by roughness measurements and SEM observations. PET’s higher stiffness and strength accounted for its superior reinforcement relative to PP. Fractographic analysis revealed flat regions near specimen corners—interpreted as crack initiation sites—indicating that lamination delayed crack propagation. The results demonstrate that PET film lamination is an effective and practical post-processing strategy for enhancing the mechanical performance of wood–plastic composites. Full article

Background: A precise drug delivery system enables the optimization of treatments with minimal side effects if it can deliver medication only when activated by a specific light source. This study presents a controlled drug delivery system based on poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) designed for the sustained release of vancomycin hydrochloride. Methods: The MPs were co-loaded with indocyanine green (ICG), a near-infrared (NIR) responsive agent, and fabricated via the double emulsion method.They were characterized for stability, surface modification, biocompatibility, and antibacterial efficacy. Results: Dynamic light scattering and zeta potential analyses confirmed significant increases in particle size and surface charge reversal following chitosan coating. Scanning electron microscopy revealed uniform morphology in uncoated MPs (1–10 $\mathsf{\mu }$m) and irregular surfaces post-coating. Stability tests demonstrated drug retention for up to 180 days. Among formulations, PVI1 exhibited the highest yield (76.67 ± 1.3%) and encapsulation efficiency (56.2 ± 1.95%). NIR irradiation (808 nm) enhanced drug release kinetics, with formulation PVI4 achieving over 48.9% release, resulting in improved antibacterial activity. Chitosan-coated MPs (e.g., PVI4-C) effectively suppressed drug release without NIR light for up to 8 h, with cumulative release reaching only 10.89%. Without NIR light, bacterial colonies exceeded 1000 CFU; NIR-triggered release reduced them below 120 CFU. Drug release data fitted best with the zero-order and Korsmeyer–Peppas models, suggesting a combination of diffusion-controlled and constant-rate release behavior. Conclusions: These results demonstrate the promise of chitosan-coated NIR-responsive PLGA MPs for precise, on-demand antibiotic delivery and improved antibacterial performance. Full article

Underground spaces offer significant potential for sustainable urban development, particularly in cold climate regions where surface thermal fluctuations are extreme. However, optimizing the wind–heat environmental performance of such spaces remains insufficiently explored, especially in relation to spatial morphology. This study addresses this gap by investigating how underground spatial configurations influence thermal comfort and ventilation efficiency. Six representative spatial prototypes—fully enclosed, single-side open, double-side open, central atrium, wind tower, and earth kiln—were constructed based on common underground design typologies. Computational fluid dynamics (CFD) simulations were conducted to evaluate airflow patterns and thermal responses under winter and summer conditions, incorporating relevant geotechnical properties into the boundary setup. The results indicate that deeper burial depths enhance thermal stability, while central atrium and wind tower prototypes offer the most balanced performance in both ventilation and heat regulation. These findings provide valuable design guidance for climate-responsive underground developments and contribute to the interdisciplinary integration of building physics, spatial design, and geotechnical engineering. Full article

The integral welded panel represents a highly promising aircraft structural component, owing to its lightweight design and reduced connector requirements. However, the complexity of its welded structure results in the formation of cross-welded joints. This study systematically investigated the mechanical properties of the cross-welded joints through tensile tests across different welded regions, which were complemented by fracture morphology examination via scanning electron microscopy (SEM). The residual stress distribution was characterized using X-ray diffraction, while electron backscatter diffraction (EBSD) analysis was used to elucidate the relationship between residual stress and microstructure. Key findings revealed that the cross-welded zone exhibited lower yield strength and ductility than the single-welded zone, and the advancing heat-affected zone demonstrated superior tensile properties relative to the retreating side. Residual stress analysis showed that the cross-welded joint lacked the “double peak” profile characteristic and displayed lower maximum residual stress than the single-welded joint. EBSD analysis indicated significant grain elongation in the cross-welded zone due to mechanical forces during the welding process, resulting in higher dislocation density and deformation, corresponding with elevated residual stress levels. Full article

In this paper, polymethylhydrosiloxane (PMHS) and ethanol were used as raw materials to synthesize the ceramic precursor of side ethoxy polysiloxane (PESO) using dehydration and a dealcoholization reaction, which had a ceramic yield of 87.15% and a very low residual carbon content. With the quartz fiber as a reinforcer, the silica matrix composites (SiO_2f/SiO₂) with a double-layer interface (PyC-SiO₂/BNNSs) coating were manufactured using precursor impregnation pyrolysis (PIP). The as-prepared SiO_2f/SiO₂ possessed an excellent mechanical property, which exhibited obvious fiber pull-out and debonding phenomena from a fracture morphology. The flexural strength and fracture toughness of SiO_2f/SiO₂ reached 63.3 MPa and 2.52 MPa·m^1/2, respectively. Moreover, the SiO_2f/SiO₂ had suitable dielectric properties, with a dielectric constant of about 2.5 and a dielectric loss of less than 0.01. This work provides an important concept for the enhancement of the dielectric properties and mechanical properties of quartz fiber-reinforced ceramic matrix composites, as well as in the preparation of wave-transmissivity composites. Full article

Herein, a recently developed UAV/Drone approach as a new vector for the collection of airborne particulate matter is reported. In this study, airborne particle emissions from plumes generated in a holiday fireworks display were collected. A platform fabricated using a 3D printer was mounted on the drone, which allowed for particulate capture using double-sided carbon tape attached to aluminum disks. The drone platform was used to trap airborne samples from two types of plumes: high-altitude sampling (HAS), which relates to professional fireworks, and low-altitude sampling (LAS), associated with personal fireworks. Collected samples were studied using a Scanning Electron Microscope alongside Electron Dispersal X-ray Spectroscopy (EDX) for elemental composition analysis. The overall findings regarding the physical morphology reveal several key observations. Firstly, particles from professional fireworks are significantly larger and more spheroidal than those from personal fireworks. Secondly, both types of fireworks show a consistent trend in which some of the larger particles have finer particulates deposited on their surfaces. Lastly, the plumes produced by both types contain spheres that are either solid, hollow or exhibit a core–shell structure. EDX analysis revealed the presence of various types of metals within the samples. EDX analysis shows that the samples collected from the HAS and LAS contain particulates with common elements. However, the samples from the plume of professional fireworks appear to have Ba, Mg, and Fe compared to the samples from personal fireworks. These elements are known to be used in powerful fireworks to create colored displays. A proposed mechanism for particulate growth in fireworks is proposed and discussed. Full article

In recent years, microphysiological systems (MPS) using microfluidic technology as a new in vitro experimental system have shown promise as an alternative to animal experiments in the development of drugs, especially in the field of drug discovery, and some reports have indicated that MPS experiments have the potential to be a valuable tool to obtain outcomes comparable to those of animal experiments. We have commercialized the Fluid3D-X^®, a double-layer microfluidic chip made of polyethylene terephthalate (PET), under the Japan Agency for Medical Research and Development (AMED) MPS development research project and have applied it to various organ models. When intestinal epithelial cells, Caco-2, were cultured using Fluid3D-X^® and a peristaltic pump, villi-like structures were formed in the microchannels. Still, the degree of formation differed between the upstream and downstream sides. To examine the consideration points regarding the effects of the nutrient and oxygen supply by the chip material and the medium perfusion rate and direction on cells in the widely used double-layer microfluidic chip and to demonstrate the usefulness of a new imaging evaluation method using artificial intelligence technology as an assistive tool for the morphological evaluation of cells, the cell morphology in the channels was quantified and evaluated using the Nikon NIS.ai and microscopic observation. Villi-like structures were predominant upstream of the top channel, independent of the medium perfusion on the bottom channel, and those structures downstream developed with an increased flow rate. Additionally, compared to the Fluid3D-X^®, the chip made of PDMS showed almost uniform villi-like sterilization in the channel. The result indicates that the environment within the microchannels differs because the amount of nutrients and oxygen supply varies depending on the medium’s perfusion and the material of the chips. As the amount of oxygen and nutrients required by different cell types differs, it is necessary to study the optimization of culture conditions according to the characteristics of the cells handled. It was also demonstrated that the AI-based image analysis method is helpful as a quantification method for the differences in cell morphology in the microchannel observed under a microscope. Full article

Background and objectives: The use of polymeric nanoparticles (NPs) in drug delivery systems offers the advantages of enhancing drug efficacy and minimizing side effects; Methods: In this study, L-threonine polyurethane (LTPU) NPs have been fabricated by water-in-oil-in-water emulsion and solvent evaporation using biodegradable and biocompatible LTPU. This polymer was pre-synthesized through the use of an amino acid-based chain extender, desaminotyrosyl L-threonine hexyl ester (DLTHE), where urethane bonds are formed by poly(lactic acid)-poly(ethylene glycol)-poly(lactic acid) (PLA-PEG-PLA) triblock copolymer and 1,6-hexamethylene diisocyanate (HDI). LTPU is designed to be degraded by hydrolysis and enzymatic activity due to the presence of ester bonds and peptide bonds within the polymer backbone. LTPU NPs were fabricated by water-in-oil-in-water double emulsion solvent evaporation methods; Results: The polymerization of LTPU was confirmed by ¹H-NMR, ¹³C-NMR, and FT-IR spectroscopies. The molecular weights and polydispersity, determined with GPC, were 28,800 g/mol and 1.46, respectively. The morphology and size of NPs, characterized by DLS, FE-SEM, TEM, and confocal microscopy, showed smooth and spherical particles with diameters less than 200 nm; Conclusions: In addition, the drug loading, encapsulation efficiency, and drug release profiles, using UV-Vis spectroscopy, showed the highest encapsulation efficiency with 2.5% carboplatin and sustained release profile. Full article

The multi-layered and multi-material structures of a violin’s surface varnish film make it more challenging to comprehensively understand the patterns of sound quality changes during the coating process. Using an alcohol varnish coating technique on one or both sides of the wood, along with a combination of micro-morphology, material characterization, and vibration signal processing, this study traced and analyzed the changes in the acoustic vibration properties of Norway spruce wood during the coating process. The results showed that the acoustic characteristics of the coated wood tended to change in an unfavorable direction throughout the coating process, and the specific dynamic elastic modulus (E_sp) of the final single- and double-sided coating varied by −1.77% and −6.07%, respectively. The loss angle tangent (tanδ) had the opposite trend, with rates of change of 20.76% and 30.42%. The sizing and priming treatments in the pretreatment stage had some positive effects on the acoustic properties of the wood specimens. Additionally, significant changes in acoustic vibration performance parameters began to be highlighted at the color paint stage (p < 0.05). These insights provide reference data for the improvement of violin acoustic performance and the simplification of the coating process. Full article

Background: Acetabular fractures continue to pose a major challenge in clinical practice, not least because of the growing geriatric population. While the influence of the force vectors on fracture formation is well established, the impact of anatomical factors on fracture morphology remains poorly understood. The aim of this study was to investigate patient-specific hip joint geometry, identify structural risk factors and correlate these with the resulting fracture patterns. Methods: This retrospective cohort analysis included 226 patients (Mdn age = 58 yrs.) with acetabular fracture categorized by Judet/Letournel and the AO/OTA classification. Computed tomography (CT) datasets of the injured and contralateral sides were analyzed using multiplanar reconstruction. Parameters included modified center-edge (CE) angle (Wiberg), rotation angles (Ullmann and Anda), acetabular sector angle (Anda), true caput-collum-diaphyseal (CCD) angle, femoral head diameter and volume, as well as femoral neck length, circumference, and diameter. In addition, intrarater reliability within a subcohort was assessed for the metric measurements and inter-rater analysis for the classification of the entire sample. Results: The primary analysis showed direct effects of femoral head diameter, femoral neck length and femoral head size on the fracture type according to AO/OTA (type A/B/C), whereby this effect was particularly seen between type A and type C fractures (p = 0.001). Ordinal regression identified femoral head diameter as the only significant predictor (p = 0.02), with a 25% increased likelihood of complex fractures per unit of change. Low-energy trauma doubled the risk of severe fractures. Specific findings include a higher acetabular anteversion in anterior column fractures. Age correlated positively with the cause of injury and fracture type. The inter-rater reliability for fracture classification was excellent, as was the intrarater reliability of the measurements. Conclusions: This study suggests that anatomical factors, particularly proximal femoral geometry, have an impact on acetabular fracture morphology—in addition to factors such as trauma type and patient demographics. Full article

Emergency breakaway pins (EBPs) have been widely used in aircraft, especially in the suspension connection between the engine device and the airfoil. Currently, the existing EBPs, which are made of metal materials, barely satisfy the lightweight requirement of the airplane industry. Thus, the construction of a novel EBP with quartz fiber reinforced phenolics is proposed in this study, and the shear response is examined experimentally using a double-sided shear test. The effect of the fiber distribution characteristic on the shear strength is then assessed quantitatively. The failure patterns, including the damage morphology of the two types of samples were then reconstructed using scanning electron microscopy (SEM). Experimental results showed that the breakaway composite pin fabricated by the laminated composite had a superior shear response than its counterpart with randomly distributed fibers for its uniaxially distributed fiber yarns provided a longer put-out damage trace that contributed to a higher shear-loading bearing capacity for the entire composite EBP. In specific, the average values of the shear strength and the shear stiffness for the former samples were higher by 61% and 22%, respectively, than that for the latter samples. Additionally, the composite EBP also has an excellent combination of lightweight advantage and stronger shear-bearing capacity over competing pins, providing novel insight for more secure designs for civil and military aviation. Full article

The triboelectric nanogenerator (TENG) has demonstrated exceptional efficiency in harvesting diverse forms of mechanical energy and converting it into electrical energy. This technology is particularly valuable for powering low-energy electronic devices and self-powered sensors. Most traditional TENGs use single-sided patterned friction pairs, which restrict their effective contact area and overall performance. Here, we propose a novel TENG that incorporates microwave patterned aluminum (MC-Al) foil and microcone structured polydimethylsiloxane (MC-PDMS). This innovative design utilizes two PMMA molds featuring identical micro-hole arrays ablated by a CO₂ laser, making it both cost-effective and easy to fabricate. A novel room imprinting technique has been employed to create the micromorphology of aluminum (Al) foil using the PMMA mold with shallower micro-hole arrays. Compared to TENGs with flat friction layers and single-side-patterned friction layers, the double-side-patterned MW-MC-TENG demonstrates superior output performance due to increased cone deformation and contact area. The open-circuit voltage of the MW-MC-TENG can reach 141 V, while the short-circuit current can attain 71.5 μA, corresponding to a current density of 2.86 µA/cm². The power density reaches 1.4 mW/cm² when the resistance is 15 MΩ, and it can charge a 0.1 μF capacitor to 2.01 V in 2.28 s. In addition, the MW-MC-TENG can function as an insole device to harvest walking energy, power 11 LED bulbs, monitor step speed, and power a timer device. Therefore, the MW-MC-TENG has significant application potential in micro-wearable devices. Full article

Chagas disease (CD) is a worldwide public health problem. Benznidazole (BZ) is the drug used to treat it. However, in its commercial formulation, it has significant side effects and is less effective in the chronic phase of the infection. The development of particulate systems containing BZ is therefore being promoted. The objective of this investigation was to develop polymeric nanoparticles loaded with BZ and examine their trypanocidal impact in vitro. Two formulas (BNP1 and BNP2) were produced through double emulsification and freeze drying. Subsequent to physicochemical and morphological assessment, both formulations exhibited adequate yield, average particle diameter, and zeta potential for oral administration. Cell viability was assessed in H9C2 and RAW 264.7 cells in vitro, revealing no cytotoxicity in cardiomyocytes or detrimental effects in macrophages at specific concentrations. BNP1 and BNP2 enhanced the effect of BZ within 48 h using a treatment of 3.90 μg/mL. The formulations notably improved NO reduction, particularly BNP2. The findings imply that the compositions are suitable for preclinical research, underscoring their potential as substitutes for treating CD. This study aids the quest for new BZ formulations, which are essential in light of the disregard for the treatment of CD and the unfavorable effects associated with its commercial product. Full article

The concrete piers in steep mountain areas are highly susceptible to damage disasters due to the impact of debris avalanches, which pose a serious threat to the safe operation of bridge structures. In order to investigate the impact load characteristics of debris avalanches on bridge pier structures in V-shaped valley mountain areas, Particle Flow Code 3D (PFC^3D) models based on a discrete element method were applied in this study to establish a full-scale three-dimensional model of a debris avalanche in a V-shaped valley. By installing double-column piers in the influence zone of the debris avalanche, the impact force, accumulation morphology, motion characteristics of debris particles, internal force response of the double-column piers, and impact energy indicators were investigated. In addition, parameters such as the layout position of the piers and the impact angle of the debris were studied. The results showed that the particles at the front edge of the debris avalanche have a significant impact on the magnitude and distribution of the impact force on the piers. It is important to consider the layout position of the piers and the impact angle of the debris when designing bridge pier structures in high, steep mountain areas. There was a significant difference in the movement patterns between the particles at the front and rear edges of the landslide. The particles at the front edge had a higher velocity and stronger impact, while the particles at the rear edge had a slower velocity and were more likely to be obstructed by bridge piers, leading to accumulation. The obstruction effect of the piers on the debris particles was closely related to their positioning and the impact angle. Piers that were closer to the center of the valley and had a larger impact angle have a more significant obstruction effect, and the topography of the valley had a significant focusing effect on the debris avalanche, resulting in a greater impact force and energy on the piers located closer to the center of the valley. The impact force amplitude and duration of landslide debris on bridge piers showed a significant difference between the bottom and upper piers, as well as between the piers on the upstream and downstream sides. These research findings can provide valuable references for the design and disaster assessment of bridge piers for impact prevention in steep slopes and mountainous areas with deep ravines. Full article

(1) Background: Structural remodeling plays an important role in the pathophysiology of atrial fibrillation (AF). It is likely that structural remodeling occurs transmurally, giving rise to electrical endo-epicardial asynchrony (EEA). Recent studies have suggested that areas of EEA may be suitable targets for ablation therapy of AF. We hypothesized that the degree of EEA is more pronounced in areas of transmural conduction block (T-CB) than single-sided CB (SS-CB). This study examined the degree to which SS-CB and T-CB enhance EEA and which specific unipolar potential morphology parameters are predictive for SS-CB or T-CB. (2) Methods: Simultaneous endo-epicardial mapping in the human right atrium was performed in 86 patients. Potential morphology parameters included unipolar potential voltages, low-voltage areas, potential complexity (long double and fractionated potentials: LDPs and FPs), and the duration of fractionation. (3) Results: EEA was mostly affected by the presence of T-CB areas. Lower potential voltages and more LDPs and FPs were observed in T-CB areas compared to SS-CB areas. (4) Conclusion: Areas of T-CB could be most accurately predicted by combining epicardial unipolar potential morphology parameters, including voltages, fractionation, and fractionation duration (AUC = 0.91). If transmural areas of CB indeed play a pivotal role in the pathophysiology of AF, they could theoretically be used as target sites for ablation. Full article