High Loading Capacity Research Articles

Experiments of Lift-Bending Response on a Slender UAV Wing Structure with Control Surface under Extreme Flow Turbulence

The aeroelastic response of lightweight low-speed aircrafts with slender wings under extreme flow turbulence intensity is not well understood. Experiments on a commercial unmanned aerial vehicle (UAV) with a 3 m wingspan and aspect ratio of 13.6 were performed in a large open-return wind tunnel with extreme flow turbulence intensity of ≈10%. The wing bending displacement and the flow beneath the wing were measured by using laser-displacement sensors and tomographic particle image velocimetry (PIV) techniques, respectively. The unsteady lift produced by the wing was also measured by using a high-capacity load cell at an angle of attack of two degrees for three freestream velocities of 13.4 m/s, 17.9 m/s, and 26.8 m/s, representing the UAV’s stall speed, a speed approximately equal to the cruise speed, and a speed considerably higher than the cruise speed, respectively. It was found that a high flow turbulence intensity with large integral length scales relative to the wing chord plays a dominant role in the large unsteady lift and wing displacements measured. The power spectral density (PSD) of the wing structural vibration shows that flow shedding from the wing and the integral length scales have a significant impact on the overall power inherent in the bending vibration of the wing. Computations of the vorticity isosurfaces in the flow measurement volume surrounding the aileron reveal a striking observation: an aileron deflection of 10° becomes less effective in producing additional spanwise vorticity, which is proportional to circulation and lift at 26.8 m/s since the freestream already has elevated levels of vorticity. A paradigm shift in design is suggested for light aircraft structures with slender wings operating in highly turbulent flow, which is to employ multiple control surfaces in order to respond to this flow and mitigate large bending or torsion displacements and the probability of structural failure.

Sliding mode control with self-adaptive parameters of a 5-DOF hybrid robot.

Due to the advantages of high stiffness, high precision, high load capacity and large workspace, hybrid robots are applicable to drilling and milling of complicated components with large sizes, for instance car panels. However, the difficulty in establishing an exact dynamic model and external disturbances affect the high accuracy control directly, which will decrease the machining accuracy and thereby affect the machining quality and efficiency of the system. Sliding mode control is an effective approach for high-order nonlinear dynamic systems since that it is very insensitive to disturbances and parameter variations. However, chattering may exist in traditional sliding mode control with fixed parameters, which results from a constant approaching speed. Besides, the approaching speed will affect the chattering strength directly. To solve these problems, a modified sliding mode controller with self-adaptive parameters is proposed to enhance the trajectory-tracking performance of a 5-degree-of-freedom hybrid robot. Firstly, the kinematic model of the robot is established. Then adopting the principle of virtual work, a rigid dynamic model of the robot is built. Based on the built dynamic model, a modified sliding mode control method is developed, of which the approaching speed is dependent on the system state. Finally, the sliding mode controller with self-adaptive parameters is created for a hybrid robot. The proposed sliding mode controller can achieve a rapid approaching speed and suppress chattering simultaneously. Simulation results demonstrate that the proposed modified sliding mode controller can achieve a comparatively accurate and smooth trajectory, which owns good robustness to external disturbances.

A Seahorse-Inspired Continuum Robot With High Load Capacity

A Seahorse-Inspired Continuum Robot With High Load Capacity

Combination of click chemistry and Schiff base reaction: Post-synthesis of covalent organic frameworks as an immobilized metal ion affinity chromatography platform for efficient capture of global phosphopeptides in serum with chronic obstructive pulmonary disease.

Reasonable design and construction of functionalized materials are of great importance for the enrichment of global phosphopeptides. In this work, Ti4+ functionalized hydrophilic covalent organic frameworks by introducing glutathione (GSH) and 2,3,4-trihydroxy benzaldehyde (THBA) via click chemistry and Schiff base reaction (COF-V@GSH-THBA-Ti4+ ) was constructed and applied for selective enrichment of phosphopeptides in serum. Benefit from the high surface area, excellent hydrophilicity as well as regular mesoporous structure, COF-V@GSH-THBA-Ti4+ displayed high selectivity (molar ratio of 2000:1), low limit of detection (0.5 fmol), high load capacity (100.0mg/g) and excellent size-exclusion effect (1:10000) for enrichment of phosphopeptides. For actual bio-sample analysis, 15 phosphopeptides assigned to 10 phosphoproteins with 16 phosphorylated sites and 33 phosphopeptides assigned to 25 phosphoproteins with 34 phosphorylated sites were detected from the serum of patients with chronic obstructive pulmonary disease (COPD), and normal controls. Biological processes and molecular functions analysis further disclosed the difference of serums with phosphoproteomics between COPD and normal controls.

Zinc oxide nanoparticles intercalated with porous carbon as a separator coating for improving the stability of lithium metal anodes.

Metal lithium negative electrodes are considered the "holy grail" of lithium battery negative electrodes due to their ultra-high energy density and low overpotential. However, the arbitrary growth of lithium dendrites during the cycling process hindered its industrialization process. We prepared porous carbon doped with zinc oxide nanoparticles (ZNC-MOF-5) by high-temperature carbonization of MOF-5, and coated ZNC-MOF-5 on the surface of commercial membranes (ZNC-MOF-5@PP). Used to improve the cycling stability of metal lithium negative electrodes. Zinc oxide nanoparticles in ZNC-MOF-5 have good lithium affinity and can promote Li+ deposition. The porous structure with a high specific surface area endows the electrode with high lithium loading capacity, reduces local current density, and obtains a dendrite-free metal lithium negative electrode. The electrochemical cycling performance of Li/Cu batteries indicates that, ZNC-MOF-5@PP. The separator can prevent the growth of dendrites and improve cycling stability, proving that ZNC-MOF-5 can effectively guide the deposition of Li and solve dendrite problems.

Enhancing Bone Cement Efficacy with Hydrogel Beads Synthesized by Droplet Microfluidics

Effective filling materials, typically bone cements, are essential for providing mechanical support during bone fracture treatment. A current challenge with bone cement lies in achieving continuous drug release and forming porous structures that facilitate cell migration and enhance osteoconductivity. We report a droplet microfluidics-based method for synthesizing uniform-sized gelatin hydrogel beads. A high hydrogel concentration and increased crosslinking levels were found to enhance drug loading as well as release performance. Consequently, the droplet microfluidic device was optimized in its design and fabrication to enable the stable generation of uniform-sized droplets from high-viscosity gelatin solutions. The size of the generated beads can be selectively controlled from 50 to 300 μm, featuring a high antibiotic loading capacity of up to 43% dry weight. They achieve continuous drug release lasting more than 300 h, ensuring sustained microbial inhibition with minimal cytotoxicity. Furthermore, the hydrogel beads are well suited for integration with calcium phosphate cement, maintaining structural integrity to form porous matrices and improve continuous drug release performance. The uniform size distribution of the beads, achieved through droplet microfluidic synthesis, ensures predictable drug release dynamics and a measurable impact on the mechanical properties of bone cements, positioning this technology as a promising enhancement to bone cement materials.

Unlocking the Potential of Cable-Driven Continuum Robots: A Comprehensive Review and Future Directions

Rigid robots have found wide-ranging applications in manufacturing automation, owing to their high loading capacity, high speed, and high precision. Nevertheless, these robots typically feature joint-based drive mechanisms, possessing limited degrees of freedom (DOF), bulky structures, and low manipulability in confined spaces. In contrast, continuum robots, drawing inspiration from biological structures, exhibit characteristics such as high compliance, lightweight designs, and high adaptability to various environments. Among them, cable-driven continuum robots (CDCRs) driven by multiple cables offer advantages like higher dynamic response compared to pneumatic systems and increased working space and higher loading capacity compared to shape memory alloy (SMA) drives. However, CDCRs also exhibit some shortcomings, including complex motion, drive redundancy, challenging modeling, and control difficulties. This study presents a comprehensive analysis and summary of CDCR research progress across four key dimensions: configuration design, kinematics and dynamics modeling, motion planning, and motion control. The objective of this study is to identify common challenges, propose solutions, and unlock the full potential of CDCRs for a broader range of applications.

Controllable sulfur redox multi-pathway reactions regulated by metal-free electrocatalysts anchored with LiS3* radicals

Regulating sulfur redox kinetics is an effective strategy for addressing the critical issues in lithium-sulfur batteries and improving their comprehensive performance. However, the sluggish and complex sulfur reduction reaction (SRR) kinetics can seriously deteriorate the electrochemical performance of lithium-sulfur batteries, hindering a clear comprehension of the electrocatalytic mechanism and presenting challenges for targeted design. Hence, it is crucial to elucidate the SRR mechanism and further refine the catalytic principle. In this study, the SRR mechanism and the pivotal role of radicals are comprehensively explored using ultrathin nitrogen-oxygen co-doped carbon nanosheets (UN/O-CNS) as an electrocatalytic model, combining density functional theory calculations with experimental techniques, such as X-ray absorption near-edge structure spectroscopy. The abundant N-O active sites of UN/O-CNS can synergistically anchor LiS3* radicals, facilitating efficient multi-pathway sulfur conversion. Additionally, UN/O-CNS can capture and catalyze polysulfides while also bi-directionally catalyzing Li2S. The S@UN/O-CNS cells ultimately demonstrate ultra-long cycling performance and high load capacity. The successful operation in pouch cells validates the practical effectiveness of UN/O-CNS. Overall, this study offers novel insights into the complexity and potential pathways of sulfur redox reaction, providing new perspectives for exploring the catalytic mechanism of cost-effective metal-free electrocatalysts.

Biomimetic-induced hydroxyapatite for rebar corrosion mitigation in self-healing concrete beam

The corrosion of embedded rebar in self-healing concrete is seldom reported on and deserves more intensive attention. This study focuses on utilizing biomimetic-induced hydroxyapatite as a means of achieving autonomous self-healing to target issues associated with rebar corrosion in concrete structures. A comprehensive evaluation of the synthesized supramolecular hydrogel as self-healing agent carrier, the simulated self-healing products, and the reinforcement corrosion behaviour in the upscaled self-healing concrete beams was conducted. Results show that the synthesized 2,6-bis [N-(carboxyethyl carbonyl)amino] pyridine (DAP) hydrogel qualifies as a healing agent carrier with high loading capacity and intelligent response after cracking. The feasibility of hydroxyapatite formation via a combination of phosphate ions released by the supramolecular hydrogel and the available calcium ions leached by the cement matrix has been substantiated. The addition of phosphate as the healing agent is effective in mitigating the corrosion of rebar in the designed self-healing concrete beam. It can be explained by the synergistic effect of surface adsorption of chloride ions by the formed hydroxyapatite and the corrosion inhibitor role of the released phosphate.

Advances in superparamagnetic iron oxide nanoparticles modified with branched polyethyleneimine for multimodal imaging

Multimodal imaging are approaches which combines multiple imaging techniques to obtain multi-aspect information of a target through different imaging modalities, thereby greatly improve the accuracy and comprehensiveness of imaging. Superparamagnetic iron oxide nanoparticles (SPIONs) modified with branched polyethyleneimine have revealed good biocompatibility and stability, high drug loading capacity and nucleic acid transfection efficiency. SPIONs have been developed as functionalized platforms which can be further modified to enhance their functionalities. Those further modifications facilitate the application of SPIONs in multimodal imaging. In this review, we discuss the methods, advantages, applications, and prospects of BPEI-modified SPIONs in multimodal imaging.

Tunable self-assembly of lipid-based block polymeric micelles with temperature-sensitive poly(vinylcaprolactam) shell for effective anticancer drug delivery

Lipids, as naturally occurring biomolecules have emerged as promising carriers for delivering various therapeutic agents. However, only a few attempts have been made in terms of their applications as amphiphilic block copolymers for anticancer drug delivery. In this work, a biocompatible micellar drug delivery system with fatty acid-based polymer core and temperature-sensitive shell was developed. A series of amphiphilic block copolymers poly(vinyl stearate)/poly(vinyl laurate)-b-poly(N-vinylcaprolactam) (PVS/PVL-b-PNVCL) were synthesized via microwave-assisted reversible addition-fragmentation chain transfer polymerization in a controlled fashion. By varying the fatty acid type and hydrophilic/hydrophobic block lengths, the self-assembly behaviour of the block copolymer micelles proved to be highly tunable in terms of their morphology and particle size. Nile Red and hydrophobic anticancer drug doxorubicin (DOX) were effectively incorporated into the micelles, demonstrating high drug loading capacity, good serum stability, and temperature-dependent drug release characteristics of the polymeric micelles. In vitro studies using cell models revealed that blank PVS -b-PNVCL micelles are biocompatible with different cell lines, while DOX-loaded micelles were internalized into and accumulated in the cells, showing a high cytotoxic effect against HeLa cells. These findings suggest an opportunity for the development of safe and efficient lipid-based micellar system for smart drug delivery and cancer treatments.

A stable, highly concentrated fluorous nanoemulsion formulation for in vivo cancer imaging via 19F-MRI.

Magnetic resonance imaging (MRI) is a routine diagnostic modality in oncology that produces excellent imaging resolution and tumor contrast without the use of ionizing radiation. However, improved contrast agents are still needed to further increase detection sensitivity and avoid toxicity/allergic reactions associated with paramagnetic metal contrast agents, which may be seen in a small percentage of the human population. Fluorine-19 (19F)-MRI is at the forefront of the developing MRI methodologies due to near-zero background signal, high natural abundance of 100%, and unambiguous signal specificity. In this study, we have developed a colloidal nanoemulsion (NE) formulation that can encapsulate high volumes of the fluorous MRI tracer, perfluoro-[15-crown-5]-ether (PFCE) (35% v/v). These nanoparticles exhibit long-term (at least 100 days) stability and high PFCE loading capacity in formulation with our semifluorinated triblock copolymer, M2F8H18. With sizes of approximately 200 nm, these NEs enable in vivo delivery and passive targeting to tumors. Our diagnostic formulation, M2F8H18/PFCE NE, yielded in vivo 19F-MR images with a high signal-to-noise ratio up to 100 in a tumor-bearing mouse model at clinically relevant scan times. M2F8H18/PFCE NE circulated stably in the vasculature, accumulated in high concentration of an estimated 4-9 × 1017 19F spins/voxel at the tumor site, and cleared from most organs over the span of 2 weeks. Uptake by the mononuclear phagocyte system to the liver and spleen was also observed, most likely due to particle size. These promising results suggest that M2F8H18/PFCE NE is a favorable 19F-MR diagnostic tracer for further development in oncological studies and potential clinical translation.

Fast Kinetics Design for Solid-State Battery Device.

Fast kinetics of solid-state batteries at the device level is not adequately explored to achieve fast charging and discharging. In this work, a leap forward is achieved for fast kinetics in full cells with high cathode loading and areal capacity. This kinetic improvement is achieved by designing a hierarchical structure of electrode composites. In the cathode, the authors' design enables high areal capacities above 3 mAh cm-2 to be stably cycled at high current densities of ≈13-40mA cm-2, yielding a C-rate from 5 to 10 C. In the anode, the authors' design breaks the common rule of the negative correlation between critical C-rate and the discharge voltage that is observed in most other anodes. The overall design enables the fast cycling of such batteries for over 4000 cycles at room temperature and 5 C charge-rate. The design principles unveiled by this work help to understand critical kinetic processes in battery devices that limit the fast cycling at high cathode loading and speed up the design of high-performance solid-state batteries.

Self-Assembled DNA Nanospheres Driven by Carbon Dots for MicroRNAs Imaging in Tumor via Logic Circuit.

DNA nanostructures with diverse biological functions have made significant advancements in biomedical applications. However, a universal strategy for the efficient production of DNA nanostructures is still lacking. In this work, a facile and mild method is presented for self-assembling polyethylenimine-modified carbon dots (PEI-CDs) and DNA into nanospheres called CANs at room temperature. This makes CANs universally applicable to multiple biological applications involving various types of DNA. Due to the ultra-small size and strong cationic charge of PEI-CDs, CANs exhibit a dense structure with high loading capacity for encapsulated DNA while providing excellent stability by protecting DNA from enzymatic hydrolysis. Additionally, Mg2+ is incorporated into CANs to form Mg@CANs which enriches the performance of CANs and enables subsequent biological imaging applications by providing exogenous Mg2+. Especially, a DNAzyme logic gate system that contains AND and OR Mg@CANs is constructed and successfully delivered to tumor cells in vitro and in vivo. They can be specifically activated by endogenic human apurinic/apyrimidinic endonuclease 1 and recognize the expression levels of miRNA-21 and miRNA-155 at tumor sites by logic biocomputing. A versatile pattern for delivery of diverse DNA and flexible logic circuits for multiple miRNAs imaging are developed.

Simulation and Experimental on Thermal Behavior of Hydrostatic Thrust Bearing Based on Superhydrophobic/oleophobic Surface

Abstract The temperature rises of oil film in hydrostatic bearings at high-speed lead to a reduction in load capacity, accuracy and stability. In this paper, a superhydrophobic/oleophobic surface with micro-bulges structure is proposed. The surface is prepared by laser cross-scanning and chemical modification. The contact angle (CA) of surface is 138° and the boundary condition of surface modificated from non-slip to slip condition. The relationship between the slip length and the height of the micro-bulges structure is established by rheological experiments. By the simple partial simulations, validity of the temperature rise reduction on the superhydrophobic/oleophobic surface is verified. Then a bearing test rig was set up to measure temperature and load capacity of bearings at multiple points, the performance of smooth primary surface/structured oleophobic surface thrust bearings was compared. Results show that the structured bearing has lower oil film temperature and higher load capacity than the smooth bearing. The prepared oleophobic surface can effectively suppress the temperature rise at high speed conditions, and significantly increase the bearing load capacity.

Dynamic characteristics of tilting-pad coupled-bearing-rotor systems considering mixed lubrication and pad wear

The coupled bearing (including a tilting-pad journal and a thrust bearing) is mainly used in a nuclear power circulating pump to simultaneously support the high axial loads and radial loads of a vertical rotary system with minimum power loss, low vibration, and high load capacity. Its lubrication and vibration characteristics have significant effects on the operation reliability of the nuclear power circulating pump. In this paper, an original mixed-lubrication dynamic model for the coupled bearing-rotor system is proposed to study the dynamic characteristics of the system considering the effects of the pivot clearance, asperity contact, and elastic deformation. The innovation of the proposed model is that it integrates the horizontal-rocking vibrations of the rotor and pads with the mixed lubrication of the coupled bearing and the wear of journal pads and thrust pads. The effects of different external loads and pad wear levels on the dynamic characteristics of the coupled bearing-rotor system are revealed. Additionally, a series of experiments are performed to measure the vibration responses of the system, which are directly compared to the simulated responses of the proposed model for validation purposes. It is expected that the proposed mixed-lubrication dynamic model can provide practical engineering guidance for the condition monitoring and fault identification of coupled bearing-rotor systems.

Degree of methyl esterification: A key factor for the encapsulation of icaritin with pectin

Pectin is a promising nano-carrier. The degree of methyl esterification (DM) influences the physiochemical properties of pectin. However, the effect of DM on the encapsulation capacity of pectin remains unclear. In this work, low methyl-esterified pectin (LMP) and high methyl-esterified pectin (HMP) were prepared. The molecular weight, rheological properties of these pectins with various DM levels were determined. Then icaritin/pectin micelles (IPMs) were prepared using HMP and LMP. Notably, higher loading capacities (18.75–20.12 %) were observed in HMP-IPMs compared to LMP-IPMs (15.72–16.64 %). Furthermore, LMP-IPMs demonstrated a DM-dependent reduction in particle sizes, ranging from 449 to 527 nm. In contrast, the particle sizes of HMP-IPMs varied between 342 and 566 nm, with smaller particle sizes observed in HMP-IPMs at higher DM levels. A significant positive correlation was found between DM and the formation of IPMs, including encapsulation efficiency, loading capacity, Zeta potential, and polydispersity index. Alkali de-esterification showed a weak impact on the pectin structure. Hydroxyl groups like 7-OH and 5-OH of icaritin might be involved in the formation of IPMs. The hydrogen-bond interactions between pectin and icaritin could be enhanced as DM increased.

Modeling and characterization of lenalidomide-loaded tripolyphosphate-crosslinked chitosan nanoparticles for anticancer drug delivery

Tripolyphosphate-crosslinked chitosan (TPPCS) nanoparticles were employed in the encapsulation of lenalidomide (LND) using a straightforward ionic cross-linking approach. The primary objectives of this technique were to enhance the bioavailability of LND and mitigate inadequate or overloading of hydrophobic and sparingly soluble drug towards cancer cells. In this context, a quantum chemical model was employed to elucidate the characteristics of TPPCS nanoparticles, aiming to assess the efficiency of these nanocarriers for the anticancer drug LND. Fifteen configurations of TPPCS and LND (TPPCS /LND1-15) were optimized using B3LYP density functional level of theory and PCM model (H2O). AIM analysis revealed that the high drug loading capacity of TPPCS can be attributed to hydrogen bonds, as supported by the average binding energy (168 kJ mol−1). The encouraging theoretical results prompted us to fabricate this drug delivery system and characterize it using advanced analytical techniques. The encapsulation efficiency of LND within the TPPCS was remarkably high, reaching approximately 87 %. Cytotoxicity studies showed that TPPCS/LND nanoparticles are more effective than the LND drug. To sum up, TPPCS/LND nanoparticles improved bioavailability of poorly soluble LND through cancerous cell membrane. In light of this accomplishment, the novel drug delivery route enhances efficiency, allowing for lower therapy doses.

Advanced strategies for combinational immunotherapy of cancer based on polymeric nanomedicines

AbstractAlthough immunotherapy has revolutionized cancer therapy by providing efficient tumor growth suppression, long‐term protection from recurrence as well as minimized side effects, the low response rate significantly limits the clinical application of immunotherapy in board types of solid tumors. In order to improve the therapeutic efficacy, conventional therapies including radiotherapy, chemotherapy, phototherapy and chemodynamic therapy are employed to combine with immunotherapy to elicit stronger antitumor immune responses. Polymer nanomedicines are frequently utilized in synergistic immunotherapy and other therapies owing to their tunable physiochemical properties, high drug loading capacity, ease of modification and low toxicity. With elaborate design and tailored properties, polymer nanomedicines can significantly enhance antitumor efficacy by enhancing tumor specificity, priming immune cells and amplifying immune responses in tumors. However, until now, there is no review solely dedicated to the comprehensive development of polymer‐based platforms for combinational immunotherapy of cancers. Herein, this paper summarizes latest advances in the design, fabrication and application of polymer nanomedicines in combinational immunotherapy and traditional antitumor strategies including radiotherapy, chemotherapy, photothermal therapy, photodynamic therapy and other therapies. An outlook on the trajectory and potential challenges of polymer nanomedicines in bridging the gap between immunotherapy and conventional therapies is also discussed.

Lubrication mechanism and characteristics of aerostatic bearing with close-spaced micro holes

Insufficient load capacity and stiffness of aerostatic bearings with traditional inherent orifices is limiting their applications. Recently, the aerostatic bearing with close-spaced micro holes (ABMH) shows the potential of performance improvement. However, its lubrication mechanism is still not clear and the static characteristics have not been comprehensively investigated. This paper applies numerical method and extends the pneumatic resistance theory from single orifice bearing to ABMH to reveal its lubrication mechanism. The results indicate that ABMH reduces the gas flow towards the high-pressure region of bearing center and impedes the pressure decrement in this area, thus resulting in the higher load capacity and stiffness. Additionally, bearing load capacity has positive relationships with total mass flow rate and exhibits similar varying trends.