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RSC Advances Jun 2024Advances in high-efficiency solar cells introduce photon management challenges, including the difficult texturization of flat surfaces and low photon utilization at...
Advances in high-efficiency solar cells introduce photon management challenges, including the difficult texturization of flat surfaces and low photon utilization at short wavelengths. While bifacial crystalline silicon solar cells have a front pyramid structure and SiN layers reduce reflections, managing photons on the flat backside remains a challenge. To enhance light utilization, a soft nanoimprint technique was utilized to create pyramid micro-structured polyurethane films doped with europium (Eu) complex. These films, which possess anti-reflection and down-conversion properties, can be applied externally to various high-efficiency solar cells without compromising electrical performance. Research on the backside of bifacial PERC solar cells revealed that the optimal composite functional film increases the integrated current by 5.70%, with a 1.27% gain from down-conversion effects. This specialized film presents a novel approach to interface matching for different types of solar cells.
PubMed: 38915332
DOI: 10.1039/d4ra03397c -
Journal of Zhejiang University.... Jun 2024Artificial vascular graft (AVG) fistula is widely used for hemodialysis treatment in patients with renal failure. However, it has poor elasticity and compliance, leading...
Artificial vascular graft (AVG) fistula is widely used for hemodialysis treatment in patients with renal failure. However, it has poor elasticity and compliance, leading to stenosis and thrombosis. The ideal artificial blood vessel for dialysis should replicate the structure and components of a real artery, which is primarily maintained by collagen in the extracellular matrix (ECM) of arterial cells. Studies have revealed that in hepatitis B virus (HBV)-induced liver fibrosis, hepatic stellate cells (HSCs) become hyperactive and produce excessive ECM fibers. Furthermore, mechanical stimulation can encourage ECM secretion and remodeling of a fiber structure. Based on the above factors, we transfected HSCs with the hepatitis B viral X () gene for simulating the process of HBV infection. Subsequently, these -HSCs were implanted into a polycaprolactone-polyurethane (PCL-PU) bilayer scaffold in which the inner layer is dense and the outer layer consists of pores, which was mechanically stimulated to promote the secretion of collagen nanofiber from the -HSCs and to facilitate crosslinking with the scaffold. We obtained an ECM-PCL-PU composite bionic blood vessel that could act as access for dialysis after decellularization. Then, the vessel scaffold was implanted into a rabbit's neck arteriovenous fistula model. It exhibited strong tensile strength and smooth blood flow and formed autologous blood vessels in the rabbit's body. Our study demonstrates the use of human cells to create biomimetic dialysis blood vessels, providing a novel approach for creating clinical vascular access for dialysis.
Topics: Rabbits; Animals; Hepatic Stellate Cells; Renal Dialysis; Polyesters; Viral Regulatory and Accessory Proteins; Tissue Scaffolds; Transfection; Bionics; Polyurethanes; Blood Vessel Prosthesis; Extracellular Matrix; Humans; Hepatitis B virus; Collagen; Tissue Engineering; Trans-Activators
PubMed: 38910495
DOI: 10.1631/jzus.B2300479 -
Biomaterials Jun 2024Biohybrid tissue-engineered vascular grafts (TEVGs) promise long-term durability due to their ability to adapt to hosts' needs. However, the latter calls for sensitive...
Biohybrid tissue-engineered vascular grafts (TEVGs) promise long-term durability due to their ability to adapt to hosts' needs. However, the latter calls for sensitive non-invasive imaging approaches to longitudinally monitor their functionality, integrity, and positioning. Here, we present an imaging approach comprising the labeling of non-degradable and degradable TEVGs' components for their in vitro and in vivo monitoring by hybrid H/F MRI. TEVGs (inner diameter 1.5 mm) consisted of biodegradable poly(lactic-co-glycolic acid) (PLGA) fibers passively incorporating superparamagnetic iron oxide nanoparticles (SPIONs), non-degradable polyvinylidene fluoride scaffolds labeled with highly fluorinated thermoplastic polyurethane (F-TPU) fibers, a smooth muscle cells containing fibrin blend, and endothelial cells. H/F MRI of TEVGs in bioreactors, and after subcutaneous and infrarenal implantation in rats, revealed that PLGA degradation could be faithfully monitored by the decreasing SPIONs signal. The F signal of F-TPU remained constant over weeks. PLGA degradation was compensated by cells' collagen and α-smooth-muscle-actin deposition. Interestingly, only TEVGs implanted on the abdominal aorta contained elastin. XTT and histology proved that our imaging markers did not influence extracellular matrix deposition and host immune reaction. This concept of non-invasive longitudinal assessment of cardiovascular implants using H/F MRI might be applicable to various biohybrid tissue-engineered implants, facilitating their clinical translation.
PubMed: 38906013
DOI: 10.1016/j.biomaterials.2024.122669 -
Marine Genomics Jun 2024Environmental DNA (eDNA) analyses of species present in marine environments is the most effective biological diversity measurement tool currently available. eDNA...
Environmental DNA (eDNA) analyses of species present in marine environments is the most effective biological diversity measurement tool currently available. eDNA sampling methods are an intrinsically important part of the eDNA biodiversity analysis process. Identification and development of eDNA sampling methods that are as rapid, affordable, versatile and practical as possible will improve rates of detection of marine species. Optimal outcomes of eDNA biodiversity surveys come from studies employing high levels of sampling replication, so any methods that make sampling faster and cheaper will improve scientific outcomes. eDNA sampling methods that can be applied more widely will also enable sampling from a greater range of marine surface micro-habitats, resulting in detection of a wider range of organisms. In this study, we compared diversity detection by several methods for sampling eDNA from submerged marine surfaces: polyurethane foam, nylon swabs, microfibre paint rollers, and sediment scoops. All of the methods produced a diverse range of species identifications, with >250 multicellular species represented by eDNA at the study site. We found that widely-available small paint rollers were an effective, readily available and affordable method for sampling eDNA from underwater marine surfaces. This approach enables the sampling of marine eDNA using extended poles, or potentially by remotely operated vehicles, where surface sampling by hand is impractical.
PubMed: 38905943
DOI: 10.1016/j.margen.2024.101127 -
Journal of Otolaryngology - Head & Neck... 2024Minimally invasive cochlear implant surgery by using a microstereotactic frame demands solid connection to the bone. We aimed to determine the stability of commercially...
BACKGROUND
Minimally invasive cochlear implant surgery by using a microstereotactic frame demands solid connection to the bone. We aimed to determine the stability of commercially available orthodontic miniscrews to evaluate their feasibility for frame's fixation. In addition, which substitute material most closely resembles the mechanical properties of the human temporal bone was evaluated.
METHODS
Pull-out tests were carried out with five different types of orthodontic miniscrews in human temporal bone specimens. Furthermore, short fiber filled epoxy (SFFE), solid rigid polyurethane (SRPU50), bovine femur, and porcine iliac bone were evaluated as substitute materials. In total, 57 tests in human specimens and 180 tests in the substitute materials were performed.
RESULTS
In human temporal bone, average pull-out forces ranged from 220 N to 285 N between screws. Joint stiffness in human temporal bone ranged between 14 N/mm and 358 N/mm. Statistically significant differences between the tested screws were measured in terms of stiffness and elastic energy. One screw type failed insertion due to tip breakage. No significant differences occurred between screws in maximum pull-out force. The average pull-out values of SFFE were 14.1 N higher compared to human specimen.
CONCLUSION
Orthodontic miniscrews provided rigid fixation when partially inserted in human temporal bone, as evidenced by pull-out forces and joint stiffness. Average values exceeded requirements despite variations between screws. Differences in stiffness and elastic energy indicate screw-specific interface mechanics. With proper insertion, orthodontic miniscrews appear suitable for microstereotactic frame anchoring during minimally invasive cochlear implant surgery. However, testing under more complex loading is needed to better predict clinical performance. For further pull-out tests, the most suitable substitute material is SFFE.
Topics: Temporal Bone; Humans; Bone Screws; Animals; Swine; Cochlear Implantation; Materials Testing; Cadaver; Cattle; Minimally Invasive Surgical Procedures
PubMed: 38903014
DOI: 10.1177/19160216241248669 -
Scientific Reports Jun 2024Absorption methods using polyurethane foams (PUFs) have recently gained popularity in treating oil spills. However, conventional petroleum-based PUFs lack selectivity...
Absorption methods using polyurethane foams (PUFs) have recently gained popularity in treating oil spills. However, conventional petroleum-based PUFs lack selectivity and are commonly surface-modified using complicated processes that require toxic and harmful solvents to enhance their hydrophobicity and oil sorption capacities. In this paper, a novel naturally superoleophilic foam with inherent hydrophobic properties has been developed through the conventional one-shot foaming method with the integration of coconut oil-based polyol. This bio-based polyol was explicitly handpicked as it is chiefly saturated, highly abundant, and inexpensive. The foam is characterized by an oil sorption capacity range of 14.89-24.65 g g for different types of oil, equivalent to 578-871 times its weight. Its hydrophobic behavior is expressed through a water contact angle of ~ 139°. The foam also showcased excellent chemical stability and high recyclability without a significant loss in absorption capacity after 20 cycles. The incorporation of the coconut oil-based polyol is also shown to improve the morphological, mechanical, and thermal behavior of the foam. It can be inferred from these findings that this novel material holds great potential for revolutionizing sorbents, pioneering a more sustainable and eco-friendly functional material produced via a facile method.
PubMed: 38902271
DOI: 10.1038/s41598-024-64178-2 -
RSC Advances Jun 2024Polymer foams can have heterogeneous and complex internal structures, especially when material blends or particles have been integrated to create composites. It becomes...
Polymer foams can have heterogeneous and complex internal structures, especially when material blends or particles have been integrated to create composites. It becomes even more challenging to probe and understand foam structure/properties when using non-uniform particles, such as biobased fillers. Optical or SEM imaging can only provide limited information as these are two-dimensional (2D) surface techniques. In this study, 3D X-ray tomography was applied to comprehensively analyze the structural features of biobased polyurethane foams containing porous rice hull fillers. The in-depth characterization at a wide range of length scale enabled us to quantify and obtain statistics of the unique trends in foam pore size and pore orientation corresponding to rice hull particle fraction and particle size. Rice hull particles were found to induce smaller cell formation. In addition, these biobased particles influenced cell expansion and caused cells to have less consistent orientation. Furthermore, after foam samples were subjected to cyclic compressive loading, X-ray tomography showed fractures in large (>100 μm) particles. This helps reveal the premature failing mechanism of composite foams with highly porous and coarse particles. The study elucidates novel microstructural evolution and deformation mechanisms using 3D X-ray tomography. The results offer new insights on internal structures for biobased composites and foams that are not previously possible through the conventional characterization tools.
PubMed: 38895520
DOI: 10.1039/d4ra02461c -
Materials (Basel, Switzerland) Jun 2024Polyurethane polishing pads are important in chemical mechanical polishing (CMP). Thus, understanding how to decrease the density but increase the porosity is a crucial...
Polyurethane polishing pads are important in chemical mechanical polishing (CMP). Thus, understanding how to decrease the density but increase the porosity is a crucial aspect of improving the efficiency of a polyurethane polishing pad. According to the principle of gas generation by thermal decomposition of sodium bicarbonate and ammonium bicarbonate, polyurethane polishing pad was prepared by a secondary foaming method. The influence of adding such an inorganic foaming agent as an auxiliary foaming agent on the structure, physical properties, and mechanical properties of polyurethane polishing pads was discussed. The results showed that compared with the polyurethane polishing pad without an inorganic foaming agent, the open-pore structure increased, the density decreased, and the porosity and water absorption increased significantly. The highest porosity and material removal rate (MRR) with sodium bicarbonate added was 3.3% higher than those without sodium bicarbonate and 33.8% higher than those without sodium bicarbonate. In addition, the highest porosity and MRR with ammonium bicarbonate were 7.2% higher and 47.8% higher than those without ammonium bicarbonate. Therefore, it was finally concluded that the optimum amount of sodium bicarbonate to be added was 3 wt%, and the optimum amount of ammonium bicarbonate to be added was 1 wt%.
PubMed: 38894023
DOI: 10.3390/ma17112759 -
Materials (Basel, Switzerland) Jun 2024Additive manufacturing (AM) is often used to create designs inspired by topology optimization and biological structures, yielding unique cross-sectional geometries...
Additive manufacturing (AM) is often used to create designs inspired by topology optimization and biological structures, yielding unique cross-sectional geometries spanning across scales. However, manufacturing defects intrinsic to AM can affect material properties, limiting the applicability of a uniform material model across diverse cross-sections. To examine this phenomenon, this paper explores the influence of specimen size and layer height on the compressive modulus of polycarbonate (PC) and thermoplastic polyurethane (TPU) specimens fabricated using fused filament fabrication (FFF). Micro-computed tomography imaging and compression testing were conducted on the printed samples. The results indicate that while variations in the modulus were statistically significant due to both layer height and size of the specimen in TPU, variations in PC were only statistically significant due to layer height. The highest elastic modulus was observed at a 0.2 mm layer height for both materials across different sizes. These findings offer valuable insights into design components for FFF, emphasizing the importance of considering mechanical property variations due to feature size, especially in TPU. Furthermore, locations with a higher probability of failure are recommended to be printed closer to the print bed, especially for TPU, because of the lower void volume fraction observed near the heated print bed.
PubMed: 38893943
DOI: 10.3390/ma17112677 -
Materials (Basel, Switzerland) Jun 2024Protection against fire and the corrosion of metals is necessary to ensure human safety. Most of the fire and corrosion inhibitors do not meet the ecological...
Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene as an Environmentally Friendly Modifier for Polyurethane Powder Coatings with Increased Thermal Stability and Corrosion Resistance.
Protection against fire and the corrosion of metals is necessary to ensure human safety. Most of the fire and corrosion inhibitors do not meet the ecological requirements. Therefore, effective and ecological methods of protecting metals are currently a challenge for researchers. In this work, the influence of hexakis(4-(hydroxymethyl)phenoxy)cyclotriphosphazene (HHPCP) on the characteristics of powder coatings was examined. The coatings' properties were investigated by measuring the roughness, hardness, adhesion to the steel surface, cupping, gloss, scratch resistance, and water contact angle. The thermal stability was studied by furnace test and TGA analysis. The corrosion resistance test was carried out in a 3.5% NaCl solution. The distribution of phosphazene-derived segments in the coating was examined by GD-EOS analysis. Modified coatings show better corrosion and thermal resistance and can be used for the protection of the steel surface. Their better corrosion resistance is due to the electroactive properties of the phosphazene ring and its higher concentration at the coating surface, confirmed by GD-EOS analysis. The increase in thermal resistance is due to the effect of the formation of phosphoric metaphosphoric and polyphosphoric acids during the decomposition of HHCPC, which remain in the condensed char phase and play a crucial role in surface protection.
PubMed: 38893936
DOI: 10.3390/ma17112672