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Journal of the Royal Society, Interface Jul 2024Natural swimmers and flyers can fully recover from catastrophic propulsor damage by altering stroke mechanics: some fish can lose even 76% of their propulsive surface...
Natural swimmers and flyers can fully recover from catastrophic propulsor damage by altering stroke mechanics: some fish can lose even 76% of their propulsive surface without loss of thrust. We consider applying these principles to enable robotic flapping propulsors to autonomously repair functionality. However, direct transference of these alterations from an organism to a robotic flapping propulsor may be suboptimal owing to irrelevant evolutionary pressures. Instead, we use machine learning techniques to compare these alterations with those optimal for a robotic system. We implement an online artificial evolution with hardware-in-the-loop, performing experimental evaluations with a flexible plate. To recoup thrust, the learned strategy increased amplitude, frequency and angle of attack (AOA) amplitude, and phase-shifted AOA by approximately 110°. Only amplitude increase is reported by most fish literature. When recovering side force, we find that force direction is correlated with AOA. No clear amplitude or frequency trend is found, whereas frequency increases in most insect literature. These results suggest that how mechanical flapping propulsors most efficiently adjust to damage may not align with natural swimmers and flyers.
Topics: Animals; Robotics; Fishes; Swimming; Biomechanical Phenomena; Models, Biological; Insecta
PubMed: 38955227
DOI: 10.1098/rsif.2024.0141 -
Nanotechnology Jul 2024Microplastics and nanoplastics have been an emerging global concern, with hazardous effects on plant, animal, and human health. Their small size makes it easier for them...
Microplastics and nanoplastics have been an emerging global concern, with hazardous effects on plant, animal, and human health. Their small size makes it easier for them to spread to various ecosystems and enter the food chain; they are already widely found in aqueous environments and within aquatic life, and have even been found within humans. Much research has gone into understanding micro-/nanoplastic sources and environmental fate, but less work has been done to understand their degradation. Photocatalytic degradation is a promising green technique that uses visible or ultraviolet light in combination with photocatalyst to degrade plastic particles. While complete degradation, reducing plastics to small molecules, is often the goal, partial degradation is more common. We examined microscale polyethylene (125-150 µm in diameter) and nanoscale polystyrene (~300 nm in diameter) spheres both before and after degradation using multiple imaging techniques, especially scanning electron microscopy and electron tomography. Electron tomography is able to image the 3D exterior and interior of the nanoplastics, enabling us to observe within aggregates and inside degraded spheres, where we found potentially open interior structures after degradation. These structures may result from differences in degradation and aggregation behaviour between the different plastic types, with our work finding that polyethylene microplastics typically cracked into sharp fragments, while polystyrene nanoplastics often fragmented into smoother, more curved shapes. These and other differences, along with interior and 3D surface images, provide new details on how the structure and aggregation of polyethylene microplastics and polystyrene nanoplastics changes when degraded, which could influence how the resulting worn particles are collected or treated further.
PubMed: 38955173
DOI: 10.1088/1361-6528/ad5dc5 -
Nanotechnology Jul 2024The current work emphasizes the synthesis of a trimetallic core-shell Ag-TeO2@ZnO nanocomposites by thermo-mechanical method for the efficient photocatalytic degradation...
The current work emphasizes the synthesis of a trimetallic core-shell Ag-TeO2@ZnO nanocomposites by thermo-mechanical method for the efficient photocatalytic degradation of 2,4-Dichlorophenol and β-naphthol pollutants. The phase, crystallite size and morphological studies of the prepared Ag-TeO2@ZnO nanocomposites were studied by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. FE-SEM shows that Ag and TeO2 nanoparticles are deposited on the surface of ZnO nanotubes. The synthesized nanocomposite exhibited remarkable photocatalytic performance for the degradation of beta-naphthol (95.6%) in 40 min at the concentration of (0.6 mg/mL) and 2,4-DCP (99.6%) in 180 min (0.4 mg/mL) under natural sunlight. The electrochemical measurements were carried out using cyclic voltammetry and electrochemical impedance spectroscopy. Determination of reactive oxygen species (ROS) confirmed that the degradation of the pollutants by 5wt% Ag-TeO2@ZnO NCs was due to the formation of superoxide radicals. Electron paramagnetic resonance revealed the presence of sharp signals in pure ZnO nanoparticles at g ~1.9530 and oxygen vacancy peak at g~2.01 in 5 wt% Ag-TeO2@ZnO NCs. The reduction in the intensity of oxygen vacancy peak in 5 wt% Ag-TeO2@ZnO NCs resulted in higher ROS generation and, finally enhanced photocatalytic activity. To study the mechanism behind the degradation of pollutants, a scavenger test using histidine and ascorbic acid (ROS scavengers) was performed. The synthesized nanocomposites are highly stable and showed enhanced efficiency up to three cycles, confirming their reusability as a photocatalyst. We believe the synthesis method and the nanocomposite's high photocatalytic activity could be utilized extensively in wastewater treatment under natural sunlight.
PubMed: 38955171
DOI: 10.1088/1361-6528/ad5dc4 -
Nanotechnology Jul 2024Transition metal dichalcogenides have been extensively studied in recent years because of their fascinating optical, electrical, and catalytic properties. However,...
Transition metal dichalcogenides have been extensively studied in recent years because of their fascinating optical, electrical, and catalytic properties. However, low-cost, scalable production remains a challenge. Aerosol-assisted chemical vapor deposition (AACVD) provides a new method for scalable thin film growth. In this study, we demonstrate the growth of molybdenum disulfide (MoS) thin films using AACVD method. This method proves its suitability for low-temperature growth of MoSthin films on various substrates, such as glass, silicon dioxide, quartz, silicon, hexagonal boron nitride, and highly ordered pyrolytic graphite. The as-grown MoSshows evidence of substrate-induced strain. The type of strain and the morphology of the as-grown MoShighly depend on the growth substrate's surface roughness, crystallinity, and chemical reactivity. Moreover, the as-grown MoSshows the presence of both direct and indirect band gaps, suitable for exploitation in future electronics and optoelectronics. .
PubMed: 38955165
DOI: 10.1088/1361-6528/ad5dc1 -
Nanotechnology Jul 2024Friction phenomena in 2D materials are conventionally studied at atomic length scales in a few layers using low-load techniques. However, the advancement of 2D materials...
Friction phenomena in 2D materials are conventionally studied at atomic length scales in a few layers using low-load techniques. However, the advancement of 2D materials for semiconductor and electronic applications requires an understanding of friction and delamination at a few micrometers length scale and hundreds of layers. To bridge this gap, the present study investigates frictional resistance and delamination mechanisms in 2D tungsten diselenide (WSe2) at 10 µm length and 100 - 500 nm depths using an integrated atomic force microscopy (AFM), high-load nanoscratch, and in-situ scanning electron microscopic (SEM) observations. AFM revealed a heterogenous distribution of frictional resistance in a single WSe2 layer originating from surface ripples, with the mean increasing from 8.7 nN to 79.1 nN as the imposed force increased from 20 to 80 nN. High-load in-situ nano-scratch tests delineated the role of the individual layers in the mechanism of multi-layer delamination under an SEM. Delamination during scratch consists of stick-slip motion with friction force increasing in each successive slip, manifested as increasing slope of lateral force curves with scratch depth from 10.9 to 13.0 (x 103) Nm-1. Delamination is followed by cyclic fracture of WSe2 layers where the puckering effect results in adherence of layers to the nanoscratch probe, increasing the local maximum of lateral force from 89.3 to 205.6 µN. This establishment of the interconnectedness between friction in single-layer and delamination at hundreds of layers harbors the potential for utilizing these materials in semiconductor devices with reduced energy losses and enhanced performance. .
PubMed: 38955145
DOI: 10.1088/1361-6528/ad5dbe -
Journal of Chromatography. A Jun 2024A new, versatile, and straightforward vapor phase deposition (VPD) approach was used to prepare continuous stationary phase gradients (cSPGs) on silica thin-layer...
A new, versatile, and straightforward vapor phase deposition (VPD) approach was used to prepare continuous stationary phase gradients (cSPGs) on silica thin-layer chromatography (TLC) plates using phenyldimethylchlorosilane (PDCS) as a precursor. A mixture of paraffin oil and PDCS was placed at the bottom of an open-ended rectangular chamber, allowing the reactive silanes to evaporate and freely diffuse under a controlled atmosphere. As the volatile silane diffused across the length of the TLC plate, it reacted with the surface silanol groups thus functionalizing the surface in a gradient fashion. Characterization of the gradient TLC plates was done through UV visualization and diffuse reflectance spectroscopy (DRS). Visualizing the fluorescent gradient plates under UV radiation shows the clear presence of a gradient with the side closest to the vapor source undergoing the most modification. More quantitative characterization of the shape of the gradient was provided by DRS. The DRS showed that the degree of modification and shape of the gradient was dependent on the concentration of silane, VPD time, and relative humidity. To evaluate the chromatographic performance, a mixture of three aromatic compounds (acetaminophen (A), aspirin (As), and 3-hydroxy-2-naphthoic acid (3H)) was spotted on the high (GHP) and low phenyl (GLP) ends of the gradient TLC plates and the results compared to the separations carried out on unmodified and uniformly modified plates. The GHP TLC plates showed retention factors (Rf) of 0.060 ± 0.006, 0.391 ± 0.006, and 0.544 ± 0.006, whereas the unmodified plate displayed Rf values of 0.059 ± 0.006, 0.092 ± 0.003, and 0.037 ± 0.002 for the analytes A, As, and 3H, respectively. From the Rf values, it was observed that each modified plate exhibited different selectivity for the analytes. The GHP TLC plates exhibited better separation performance, and improved resolution compared to the GLP, unmodified, and uniformly modified plates. Overall, VPD is a new, cost-effective method for creating a gradient on the stationary phase which has the potential to advance chromatographic separation capabilities.
PubMed: 38955129
DOI: 10.1016/j.chroma.2024.465090 -
Food Chemistry Jun 2024Plant-derived extracellular vesicles (PLEVs), as a type of naturally occurring lipid bilayer membrane structure, represent an emerging delivery vehicle with immense...
Plant-derived extracellular vesicles (PLEVs), as a type of naturally occurring lipid bilayer membrane structure, represent an emerging delivery vehicle with immense potential due to their ability to encapsulate hydrophobic and hydrophilic compounds, shield them from external environmental stresses, control release, exhibit biocompatibility, and demonstrate biodegradability. This comprehensive review analyzes engineering preparation strategies for natural vesicles, focusing on PLEVs and their purification and surface engineering. Furthermore, it encompasses the latest advancements in utilizing PLEVs to transport active components, serving as a nanotherapeutic system. The prospects and potential development of PLEVs are also discussed. It is anticipated that this work will not only address existing knowledge gaps concerning PLEVs but also provide valuable guidance for researchers in the fields of food science and biomedical studies, stimulating novel breakthroughs in plant-based therapeutic options.
PubMed: 38955121
DOI: 10.1016/j.foodchem.2024.140199 -
Talanta Jun 2024Sensitive and accurate analysis of pyrophosphate (PPi) is of great importance for preventing health hazard in environment. Nevertheless, most of sensors focus on...
Sensitive and accurate analysis of pyrophosphate (PPi) is of great importance for preventing health hazard in environment. Nevertheless, most of sensors focus on sensitivity and selectivity, but practicality is also a significant quota. How to reconciling sensitivity, selectivity and practicability in one single sensor is desirable but remains challenging. Here, we created a novel metal-carbon nanozyme VO@C with two-dimensional (2D) morphology and high yet exclusive peroxidase (POD)-like activity via a glucose and NHNO-co-directed avenue, and further showed its application in constructing a portable and disposable paper-based analytical chip (PA-chip) for rapid, visual and onsite analysis of PPi. PPi etched VO to prevent the decomposition of HO into ·OH, resulting in weakened POD-like activity. In comparison with PPi deficiency, colorless TMB couldn't be oxidized into oxidized TMB with a dropped absorption at 652 nm. Therefore, obviously shallowed blue color on PA-chip surface was recorded, and demonstrated a negative relationship with PPi dosage, enabling rapid and visual detection of PPi with a limit of detection of 2.6 nM. This study demonstrated the burgeoning applications of nanozymes with POD-like activity in construction of PA-chips for PPi and will quicken the advancement of practical sensors, guaranteeing environmental safety.
PubMed: 38955106
DOI: 10.1016/j.talanta.2024.126490 -
Talanta Jun 2024The spread of the SARS-CoV-2 virus has had an unprecedented impact, both by posing a serious risk to human health and by amplifying the burden on the global economy. The...
The spread of the SARS-CoV-2 virus has had an unprecedented impact, both by posing a serious risk to human health and by amplifying the burden on the global economy. The rapid identification of the SARS-CoV-2 virus has been crucial to preventing and controlling the spread of SARS-CoV-2 infections. In this study, we propose a multilayered plasmonic nanotrap (MPNT) device for the rapid identification of single particles of SARS-CoV-2 virus in ultra-high sensitivity by surface-enhanced Raman scattering (SERS). The MPNT device is composed of arrays of concentric cylindrical cavities with Ag/SiO/Ag multilayers deposited on the top and at the bottom. By varying the diameter of the cylinders and the thickness of the multilayers, the resonant optical absorption and local electric field were optimized. The SERS enhancement factors of the proposed device are of the order of 10, which enable the rapid identification of SARS-CoV-2 N protein in concentrations as low as 1.25 × 10-12.5 × 10 g mL within 1 min. The developed MPNT SERS device provides a label-free and rapid detection platform for SARS-CoV-2 virus. The general nature of the device makes it equally suitable to detect other infectious viruses.
PubMed: 38955100
DOI: 10.1016/j.talanta.2024.126494 -
Journal of Biomechanics Jun 2024Creating musculoskeletal models in a paediatric population currently involves either creating an image-based model from medical imaging data or a generic model using...
Creating musculoskeletal models in a paediatric population currently involves either creating an image-based model from medical imaging data or a generic model using linear scaling. Image-based models provide a high level of accuracy but are time-consuming and costly to implement, on the other hand, linear scaling of an adult template musculoskeletal model is faster and common practice, but the output errors are significantly higher. An articulated shape model incorporates pose and shape to predict geometry for use in musculoskeletal models based on existing information from a population to provide both a fast and accurate method. From a population of 333 children aged 4-18 years old, we have developed an articulated shape model of paediatric lower limb bones to predict bone geometry from eight bone landmarks commonly used for motion capture. Bone surface root mean squared errors were found to be 2.63 ± 0.90 mm, 1.97 ± 0.61 mm, and 1.72 ± 0.51 mm for the pelvis, femur, and tibia/fibula, respectively. Linear scaling produced bone surface errors of 4.79 ± 1.39 mm, 4.38 ± 0.72 mm, and 4.39 ± 0.86 mm for the pelvis, femur, and tibia/fibula, respectively. Clinical bone measurement errors were low across all bones predicted using the articulated shape model, which outperformed linear scaling for all measurements. However, the model failed to accurately capture torsional measures (femoral anteversion and tibial torsion). Overall, the articulated shape model was shown to be a fast and accurate method to predict lower limb bone geometry in a paediatric population, superior to linear scaling.
PubMed: 38955093
DOI: 10.1016/j.jbiomech.2024.112211