Gripe-Needle: A Sticky Suction Cup Gripper Equipped Needle for Targeted Therapeutics Delivery

This paper presents a multi-purpose gripping and incision tool-set to reduce the number of required manipulators for targeted therapeutics delivery in Minimally Invasive Surgery. We have recently proposed the use of multi-arm Concentric Tube Robots (CTR) consisting of an incision, a camera, and a gripper manipulator for deep orbital interventions, with a focus on Optic Nerve Sheath Fenestration (ONSF). The proposed prototype in this research, called Gripe-Needle, is a needle equipped with a sticky suction cup gripper capable of performing both gripping of target tissue and incision tasks in the optic nerve area by exploiting the multi-tube arrangement of a CTR for actuation of the different tool-set units. As a result, there will be no need for an independent gripper arm for an incision task. The CTR innermost tube is equipped with a needle, providing the pathway for drug delivery, and the immediate outer tube is attached to the suction cup, providing the suction pathway. Based on experiments on various materials, we observed that adding a sticky surface with bio-inspired grooves to a normal suction cup gripper has many advantages such as, 1) enhanced adhesion through material stickiness and by air-tightening the contact surface, 2) maintained adhesion despite internal pressure variations, e.g. due to the needle motion, and 3) sliding resistance. Simple Finite Element and theoretical modeling frameworks are proposed, based on which a miniature tool-set is designed to achieve the required gripping forces during ONSF. The final designs were successfully tested for accessing the optic nerve of a realistic eye phantom in a skull eye orbit, robust gripping and incision on units of a plastic bubble wrap sample, and manipulating different tissue types of porcine eye samples.

Longitudinal sliding resistance characteristics of the WJ-8 conventional resistance fastner

In this paper, the longitudinal resistance and displacement of the WJ-8 conventional resistance fastener under vertical and torque loadings were experimentally conducted and the relationship between longitudinal resistance and displacement was established. To validate the experimental results, numerical simulation using a finite-element model of the fastener was established to obtain the longitudinal resistance variation of the conventional-resistance. Results of the analysis show that both results of the experiment and simulation are in agreements. Furthermore, the skid resistance frictional coefficient of the fastener system under the vertical load was studied and its variation rule under both vertical and torque loads was obtained. The longitudinal sliding resistance of fasteners under different torques and/or vertical loads followed a linear trend. Under load and no-load conditions, the skid-resistance frictional coefficient of the fastener system varied significantly.

Modeling Soil-Metal Sliding Resistance

HighlightsA model was developed to express soil-metal sliding resistance in terms of normal stress and sliding path length.Soil-metal sliding resistance data, different from those used to develop the model, were acceptably simulated.The model is expected to be useful in the design and development of soil-engaging equipment.Abstract. Most previous soil-material sliding resistance studies have focused on the measurement and formulation of only qualitative relationships between sliding resistance and the material type, applied normal stress, sliding path length, and/or soil-properties. Few studies have attempted to formulate quantitative mathematical relationships between soil-material sliding resistance and these factors, or to mathematically express the relative contributions of the frictional and adhesive components to the total sliding resistance. In this study, a mathematical model was developed to express the components of soil-metal sliding resistance for a clay soil as functions of applied normal stress and sliding path length. The model is restricted to soil containing enough moisture to exhibit cohesive strength, but not so much moisture to exhibit gross plastic behavior. Soil-metal sliding resistance data, different from those used to develop the model, were acceptably simulated, as the mean square error between the simulated sliding resistance and the measured sliding resistance ranged from 0.653 to 2.44. Keywords: Adhesion, Friction, Normal stress, Sliding path length, Sliding resistance.

TGF-β3 Regulates Adhesion Formation Through the JNK/c-Jun Pathway During Flexor Tendon Healing

Background: The injured flexor tendon has poor healing ability, 15 which is easy to cause tendon adhesion. It can affect the recovery of tendon function, which is still a long term and difficult task for surgeons. Transforming growth factor β (TGF-β) has been widely considered to play an important role in flexor tendon repair in recent years. Aim: This work was to investigate the anti-adhesion and anti-inflammatory effects of TGF-β3 on flex or digitorum longus (FDL) tendon repair rats. Method: Anastomosis models of tendon laceration in the flexion toes of rats were delivered with no treatment, vehicle or TGF-β3 - overexpressed adenovirus vector (ad-TGF-β3) locally to the injured tendon area from day 3 to 8. Subsequently, the expression of TGF-β3, TGF-β1/2, Smad3, Smad7, JNK, phosphorylation (p)-JNK, c-Jun and phosphorylation (p)-c-Jun were detected by western blot, the expression of Mmp9 and Mmp2 by RT-qPCR, the Range of motion (ROM) and sliding resistance by adhesion formation testing, the mechanical strength of tendon healing by biomechanical testing, the pathologic changes of flexor tendon tissues by HE staining, the expression of collagen type III by immunohistochemical staining, and the levels of IL-6, TNF-α, COX2 and IL-1β in serum by ELISA, respectively. Results: Rat models treated with no treatment showed a lower elevation of TGF-β3 and Smad7 expression, and a higher elevation of TGF-β1/2 and Smad3 expression, during day 14 to day 28. Besides, under the treatment of ad-TGF-β3, significantly increase was reflected in the expression of TGF-β3 and Smad7, ROM, as well as mechanical strength of flexor tendon, whereas significantly reduction was shown in sliding resistance, content of inflammatory cytokines, ratio of p-JNK/JNK, p-c-Jun/c-Jun, as well as the expression of TGF-β1/2, Smad3, Mmp9 and Mmp2 genes, as compared to those from vehicle treatment. Meanwhile, TGF-β3 demonstrated better pathologic recovery process with no obvious necrosis or fracture of collagen fibers. Besides, TGF-β3 revealed a significant reduction of collagen type-III expression in the flexor tendon healing tissues. Conclusion: These findings suggested that TGF-β3 effectively protected against flexor tendon injury via regulating adhesion formation.

The Recent Advances in the Mechanical Properties of Self-Standing Two-Dimensional MXene-Based Nanostructures: Deep Insights into the Supercapacitor

MXenes have emerged as promising materials for various mechanical applications due to their outstanding physicochemical merits, multilayered structures, excellent strength, flexibility, and electrical conductivity. Despite the substantial progress achieved in the rational design of MXenes nanostructures, the tutorial reviews on the mechanical properties of self-standing MXenes were not yet reported to our knowledge. Thus, it is essential to provide timely updates of the mechanical properties of MXenes, due to the explosion of publications in this filed. In pursuit of this aim, this review is dedicated to highlighting the recent advances in the rational design of self-standing MXene with unique mechanical properties for various applications. This includes elastic properties, ideal strengths, bending rigidity, adhesion, and sliding resistance theoretically as well as experimentally supported with various representative paradigms. Meanwhile, the mechanical properties of self-standing MXenes were compared with hybrid MXenes and various 2D materials. Then, the utilization of MXenes as supercapacitors for energy storage is also discussed. This review can provide a roadmap for the scientists to tailor the mechanical properties of MXene-based materials for the new generations of energy and sensor devices.