查看更多>>摘要：Soft grippers have great potential applications in daily life,since they can compliantly grasp soft and delicate objects.How-ever,the highly elastic fingers of most soft grippers are prone to separate from each other while grasping objects due to their low stiffness,thus reducing the grasping stability and load-bearing capacity.To tackle this problem,inspired from the venus flytrap plant,this work proposes a mutual-hook mechanism to restrain the separation and improve the grasping performance of soft fingers.The novel soft gripper design consists of three modules,a soft finger-cot,two Soft Hook Actuators(SHAs)and two sliding mechanisms.Here,the soft finger-cot covers on the soft finger,increasing the contact area with the target object,two SHAs are fixed to the left and right sides of the finger-cot,and the sliding mechanisms are designed to make SHAs stretch flexibly.Experiments demonstrate that the proposed design can restrain the separation of soft fingers substantially,and the soft fingers with the finger-cots can grasp objects three times heavier than the soft fingers without the proposed design.The proposed design can provide invaluable insights for soft fingers to restrain the separation while grasping,thus improving the grasping stability and the load-bearing capacity.
查看更多>>摘要：In rehabilitation training,it is crucial to consider the compatibility between exoskeletons and human legs in motion.How-ever,most exoskeletons today adopt an anthropomorphic serial structure,which results in rotational centers that are not precisely aligned with the center of the hip joint.To address this issue,we introduce a novel exoskeleton called the Parallel Hip Exoskeleton(PH-Exo)in this paper.PH-Exo is meticulously designed based on the anisotropic law of output torque.Considering the friction of the drive components,a dynamic model of the human-machine complex is established.Simulation analysis demonstrates that PH-Exo not only exhibits outstanding torque performance but also achieves high controllability in both flexion/extension and adduction/abduction directions.Additionally,a robust controller is designed to address model uncertainty,friction,and external interference.Wearing experiments indicate that under the control of the robust controller,each motor achieves excellent tracking performance.
查看更多>>摘要：We previously developed a powered hip prosthetic mechanism with kinematic functions of hip flexion-extension and abduc-tion-adduction,and its theoretical and simulation-based kinematics were verified.Because internal-external hip rotation has a positive effect on the movements of human lower limbs according to medical research,we developed a novel hip prosthetic mechanism based on a previous hip prosthesis that possesses motion characteristics similar to those of a human bionic hip,and the motion characteristics of multiple Degrees-of-Freedom(DoFs)were analyzed after kinematic modeling.Then,a walking model of the human-machine model was established,and the walking stability of an amputee,which reflects the rehabilitation effect,was explored while the hip prosthetic mechanism considered the internal-external rotation of the hip.Finally,a prototype and its verification platform were built,and kinematic validation of the hip prosthetic mechanism was carried out.The results showed that the designed Parallel Mechanism(PM)possesses human-like motion characteristics similar to those of a human bionic hip and can be used as a hip prosthesis.Moreover,the existing motion characteristic of internal-external hip rotation can enhance the walking stability of an amputee via this hip prosthetic mechanism.
查看更多>>摘要：The precise movement speed regulation is a key factor to improve the control effect and efficiency of the cyborg rats.However,the current stimulation techniques cannot realize the graded control of the speed.In this study,we achieved the multi-level speed regulation of cyborg rats in the large open field and treadmill by specifically targeting the Cuneiform Nucleus(CnF)of the Mesencephalic Locomotor Region(MLR).Detailed,we measured the influence of each stimula-tion parameter on the speed control process which included the real-time speed,accelerated speed,response time,and acceleration period.We concluded that the pulse period and the pulse width were the main determinants influencing the accelerated speed of cyborg rats.Whereas the amplitude of stimulation was found to affect the response time exhibited by the cyborg rats.Our study provides valuable insights into the regulation of rat locomotion speed and highlights the potential for utilizing this approach in various experimental settings.
查看更多>>摘要：Amplifying the intrinsic wettability of substrate material by changing the solid/liquid contact area is considered to be the main mechanism for controlling the wettability of rough or structured surfaces.Through theoretical analysis and experi-mental exploration,we have found that in addition to this wettability structure amplification effect,the surface structure also simultaneously controls surface wettability by regulating the wetting state via changing the threshold Young angles of the Cassie-Baxter and Wenzel wetting regions.This wetting state regulation effect provides us with an alternative strategy to overcome the inherent limitation in surface chemistry by tailoring surface structure.The wetting state regulation effect created by multi-scale hierarchical structures is quite significant and plays is a crucial role in promoting the superhydrophobicity,superhydrophilicity and the transition between these two extreme wetting properties,as well as stabilizing the Cassie-Baxter superhydrophobic state on the fabricated lotus-like hierarchically structured Cu surface and the natural lotus leaf.
查看更多>>摘要：Superhydrophobic coatings with high non-wetting properties are widely applied in anti-icing applications.However,the micro-nanostructures on the surfaces of superhydrophobic coatings are fragile under external forces,resulting in reduced durability.Therefore,mechanical strength and durability play a crucial role in the utilization of superhydrophobic mate-rials.In this study,we employed a two-step spraying method to fabricate superhydrophobic FEVE-based coatings with exceptional mechanical durability,utilizing fluorinated TiO2 nanoparticles and fluorinated Al2O3 microwhiskers as the fillers.The composite coating exhibited commendable non-wetting properties,displaying a contact angle of 164.84° and a sliding angle of 4.3°.On this basis,the stability of coatings was significantly improved due to the interlocking effect of A12O3 whiskers.After 500 tape peeling cycles,500 sandpaper abrasion tests,and 50 kg falling sand impact tests,the coatings retained superhydrophobicity,exhibiting excellent durability and application capability.Notably,the ice adhesion strength on the coatings was measured at only 65.4 kPa,while the icing delay time reached 271.8 s at-15 ℃.In addi-tion,throughout 500 freezing/melting cycles,statistical analysis revealed that the superhydrophobic coatings exhibited a freezing initiation temperature as low as-17.25 ℃.
查看更多>>摘要：Surface-tension-confined microfluidic devices are platforms for manipulating 2D droplets based on patterned surfaces with special wettability.They have great potential for various applications,but are still in the early stages of development and face some challenges that need to be addressed.This study,inspired by the Wenzel and slippery transition of rose petal,develops a Patterned Oil-triggered Wenzel-slippery Surface(POWS)to examine the microfluidic devices.A laser-chemical composite method is established to fabricate POWSs,which take rose-petal-like microstructures as wettability pattern and a superamphiphobic surface as the background.The prepared POWSs switched between high adhesion superhydropho-bic state and the slippery liquid-infused surface state through adding or removing the lubricant oil.In the high adhesion superhydrophobic state,the droplets can be sticked on the surface.In the slippery liquid-infused state,the droplet can slide along the wettability pattern as the designed route.A POWS-based droplet reactor is further constructed,on which,the droplets can be remotely controlled to move,mix and react,as required.Such a POWS,which manipulates droplets with surface tension controlled by the switchable wettability patterns,would be a promising candidate to construct multiple surface-tension-confined microfluidic devices.In addition,the fabrication technique and design principle proposed here may aid the development of various field related to the bio-inspired surfaces,such as water collection,desalination and high throughput analysis,etc.
查看更多>>摘要：Spine biomechanical testing methods in the past few decades have not evolved beyond employing either cadaveric stud-ies or finite element modeling techniques.However,both these approaches may have inherent cost and time limitations.Cadaveric studies are the present gold standard for spinal implant design and regulatory approval,but they introduce sig-nificant variability in measurements across patients,often requiring large sample sizes.Finite element modeling demands considerable expertise and can be computationally expensive when complex geometry and material nonlinearity are intro-duced.Validated analogue spine models could complement these traditional methods as a low-cost and high-fidelity alter-native.A fully 3D printable L-Sl analogue spine model with ligaments is developed and validated in this research.Rota-tional stiffness of the model under pure bending loading in flexion-extension,Lateral Bending(LB)and Axial Rotation(AR)is evaluated and compared against historical ex vivo and in silico models.Additionally,the effect of interspinous,intertransverse ligaments and the Thoracolumbar Fascia(TLF)on spinal stiffness is evaluated by systematic construction of the model.In flexion,model Range of Motion(ROM)was 12.92±0.11°(ex vivo:16.58°,in silico:12.96°)at 7.5Nm.In LB,average ROM was 13.67±0.12° at 7.5 Nm(ex vivo:15.21±1.89°,in silico:15.49±0.23°).Similarly,in AR,average ROM was 17.69±2.12° at 7.5Nm(ex vivo:14.12±0.31°,in silico:15.91±0.28°).The addition of interspinous and intertransverse ligaments increased both flexion and LB stiffnesses by approximately 5％.Addition of TLF showed increase in flexion and AR stiffnesses by 29％and 24％,respectively.This novel model can reproduce physiological ROMs with high repeatability and could be a useful open-source tool in spine biomechanics.
查看更多>>摘要：The disparity between the postoperative outcomes of rhinoplasty and the expected results frequently necessitates secondary or multiple surgeries as a compensatory measure,greatly diminishing patient satisfaction.However,there is renewed opti-mism for addressing these challenges through the innovative realm of Four-Dimensional(4D)printing.This groundbreaking technology enables three-dimensional objects with shape-memory properties to undergo predictable transformations under specific external stimuli.Consequently,implants crafted using 4D printing offer significant potential for dynamic adjustments.Inspired by worms in our research,we harnessed 4D printing to fabricate a Shape-Memory Polyurethane(SMPU)for use as a nasal augmentation prosthesis.The choice of SMPU was guided by its Glass Transition Temperature(Tg),which falls within the acceptable temperature range for the human body.This attribute allowed for temperature-responsive intraopera-tive self-deformation and postoperative remodeling.Our chosen animal model for experimentation was rabbits.Taking into account the anatomical structure of the rabbit nose,we designed and produced nasal augmentation prostheses with superior biocompatibility.These prostheses were then surgically implanted in a minimally invasive manner into the rabbit noses.Remarkably,they exhibited successful temperature-controlled in-surgery self-deformation according to the predetermined shape and non-invasive remodeling within a mere 9 days post-surgery.Subsequent histological evaluations confirmed the practical viability of these prostheses in a living organism.Our research findings posit that worm-inspired 4D-printed SMPU nasal prostheses hold significant promise for achieving dynamic aesthetic adjustments.
查看更多>>摘要：The creation of 3D nanofibers offering desirable functions for bone regeneration is developed due to the latest improvisa-tions to the electrospinning technique.Synthetic polymers are among the best choices for medical usage due to their lower costs,high tensile properties,and ease of spinnability compared to natural polymers.In this communication,we report a series of interventions to polymers modified with Mg-based fillers for ideal tissue engineering applications.The literature survey indicated that these filler materials(e.g.,nano-sized particles)enhanced biocompatibility,antibacterial activity,tensile strength,and anti-corrosive properties.This review discusses electrospinning parameters,properties,and applica-tions of the poly(ε-caprolactone),poly(lactic acid),poly(3-hydroxybutyric acid-co-3-hydroxy valeric acid),polyurethane,and poly(vinyl pyrrolidone)nanofibers when modified with Mg-based fillers.This report encourages researchers to use synthetic polymers with Mg as fillers and validate them for tissue engineering applications.
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