Anchor Materials Research Articles

Research on Obstacle-Avoidance Trajectory Planning for Drill and Anchor Materials Handling by a Mechanical Arm on a Coal Mine Drilling and Anchoring Robot.

At present, China's coal mine permanent tunneling support commonly uses mechanized drilling and anchoring equipment; there are low support efficiency, labor intensity, and other issues. In order to further improve the support efficiency and liberate productivity, this paper further researches the trajectory planning of the drilling and anchoring materials of the robotic arm for the drilling machine "grasping-carrying-loading-unloading" on the basis of the drilling and anchoring robotic system designed by the team in the previous stage. Firstly, the kinematic model of the robotic arm with material was established by improving the D-H parameter method. Then, the working space of the robotic arm with the material was analyzed using the Monte Carlo method. The singular bit-shaped region of the robotic arm was restricted, and obstacles were removed from the working space. The inverse kinematics was utilized to solve the feasible domain of the robotic arm with material. Secondly, in order to avoid blind searching, the guidance of the Bi-RRT algorithm was improved by adding the target guidance factor, and the two-way tree connection strategy for determining the feasible domain was combined with the Bi-RRT algorithm's feasible domain judgment bi-directional tree connection strategy to improve the convergence speed of the Bi-RRT algorithm. Then, in order to adapt to the dynamic environment and avoid the global planning algorithm from falling into the local minima, on the basis of the above planning methods, an improved Bi-RRT trajectory planning algorithm incorporating the artificial potential field was proposed, which takes the planned paths as the guiding potential field of the artificial potential field to make full use of the global information and avoid falling into the local minimization. Finally, a simulation environment was built in a ROS environment to compare and analyze the planning effect of different algorithms. The simulation results showed that the improved Bi-RRT trajectory planning algorithm incorporating the artificial potential field improved the optimization speed by 69.8% and shortened the trajectory length by 46.6% compared with the traditional RRT algorithm.

A novel design magnesium alloy suture anchor promotes fibrocartilaginous enthesis regeneration in rabbit rotator cuff repair

Regarding the current materials used for suture anchors for rotator cuff repair, there are still limitations in terms of degradability, mechanical properties, and bioactivities in clinical applications. Magnesium alloys have preliminarily been shown to promote tendon-bone healing with good prospects for application as anchor materials. However, the design of anchor structures for the degradation characteristics of magnesium alloy materials has not been considered, which is critical for the practical application of magnesium alloy anchors. The mechanism by which magnesium promotes tendon bone healing remains to be clarified. Here, we proposed a novel split hollowed magnesium alloy suture anchors for the repair of rabbit rotator cuff injury. We found that novel split hollowed magnesium alloy anchors structure effectively solved the problem of failure due to degradation of traditional eyelet structure, providing reliable suture fixation. The open architecture facilitates the metabolic resorption of the degradation products of and promotes the ingrowth of bone tissue. Histological staining showed that magnesium anchors have better ability to promote regeneration at the fibrocartilage interface compared to PLLA anchors. The higher expression of fibrocartilage markers (Aggrecan, COL2A1, and Sox9) at the tendon-bone interface in magnesium anchors, which promotes chondrocyte differentiation at the tendon-bone interface and matrix formation, which is more conducive to achieving regeneration and maturation of fibrocartilage enthesis. Hence, this study provides a basis for further research on the clinical application of degradable magnesium alloy suture anchors.

The feasibility of BeP2 monolayer as an anode material for Mg-ion batteries: A density functional theory study

Nowadays, as a practical approach to enhancing energy density of a metal ion battery, discovering efficient electrode materials is the foremost option. At the beginning and end of metal adsorption, BeP2 is inherently metallic and delivers favorable electrical conductivity. According to first-principles computations, BeP2 can be considered potentially suitable electrode materials for Mg-ion battery. Notably, fully magnesium phase Mg2BeP2 for BeP2 offers a great theoretical capacity (578.35 mAh g−1) accompanied by single layer of Mg ions, which outperforms numerous formerly reported two-dimensional options. In the interim, it has been discovered that diffusion barrier and open-circuit voltage of BeP2, subsequent to complete adsorption of metal ions, exhibited an unexpectedly diminished value of 0.21 V. Contemporary research findings can facilitate discovery of innovative electrode materials of BeP2 classification catering to needs of metal ion batteries. It can be concluded that BeP2-based composites are promising anchor materials for advanced Mg-ion batteries.

Rationalizing Functionalized MXenes as Effective Anchor Materials for Lithium–Sulfur Batteries via First-Principles Calculations

The practical application of Li-S batteries has been greatly hindered by severe shuttle effects and sluggish kinetics. Anchoring soluble lithium polysulfides (LiPSs) onto host materials by chemisorption is an effective strategy for extending battery life. In this work, we performed systematic density functional theory calculations to evaluate the anchoring performance of O/F-covered MXene (M2TC2) in lithium-sulfur batteries. Our results indicate that the moderate anchoring strength (∼2.5 eV), outstanding sulfur reduction performance (UL > -0.6 V), and low lithium ion diffusion barrier (<0.2 eV) of Mo2CF2 and V2CF2 make them promising host materials for LiPSs. We further revealed the determinants of the strength of binding of LiPSs to M2CT2. On the basis of the strong correlation among QM, χO/F, and Ea, we established a "structure-property" equation to reveal the active origin of M2CT2. We expect that the framework established in this work will accelerate the development of Li-S batteries.

Rotator cuff repair with biodegradable high-purity magnesium suture anchor in sheep model.

BackgroundRotator cuff tear has become one of the diseases affecting people's living quality. Conventional anchor materials such as titanium alloy and poly-lactic acid can lead to postoperative complications like bone defects and aseptic inflammation. Magnesium (Mg)-based implants are biodegradable and biocompatible, with strong potential to be applied in orthopaedics.MethodsIn this study, we developed a high-purity (HP) Mg suture anchor and studied its mechanical properties and degradation behavior in vitro. Furthermore, we described the use of high-purity Mg to prepare suture anchor for the rotator cuff repair in sheep.ResultsThe in vitro tests showed that HP Mg suture anchor possess proper degradation behavior and appropriate mechanical property. Animal experiment indicated that HP Mg suture anchor provided reliable anchoring function in 12 weeks and showed no toxic effect on animal organs.ConclusionIn summary, the HP Mg anchor presented in this study had favorable mechanical property and biosecurity.The translational potential of this article: The translational potential of this article is to use high-purity Mg to develop a degradable suture anchor and verify the feasibility of the application in animal model. This study provides a basis for further research on the clinical application of biodegradable high-purity Mg suture anchor.

Osteoconductive resorption characteristics of a novel biocomposite suture anchor material in rotator cuff repair

BackgroundBioabsorbable suture anchors have been associated with bone-derived complications, such as osteolysis and cyst formation, after rotator cuff repair. The purpose of this study was to assess the osseous degradation process of the novel biocomposite suture anchor material polylactic-co-glycolic acid (PLGA)/beta-tricalcium phosphate (ß-TCP)/calcium sulfate (CS) after arthroscopic single-row rotator cuff repair. The focus of interest was the appearance of osteolysis and the rate of total resorption of the implants after 21 months.MethodsForty-eight patients with 82 implanted suture anchors who had undergone arthroscopic rotator cuff repair between January 2015 and March 2016 at our institution were retrospectively evaluated by postoperative magnetic resonance imaging. The appearance of osteolysis was classified by measurement of the peri-implant fluid. The degree of resorption was measured by grading the persistent visibility of the anchor structures. The integrity of the rotator cuff tendon was analyzed to discover possible retear or anchor pull-out complications.ResultsAfter a follow-up of 21.2 (± 5.4) months, osteolysis was detected in only two anchors (2.4%), and none of these defects exceeded the diameter of the former suture anchor (5.5 mm). Fifty percent of the anchors were fully degraded and no longer visible. Furthermore, only two retears of the rotator cuff occurred, and no anchor pull-out complications were detected.ConclusionPGLA/β-TCP/CS is a fully resorbable and osteoconductive suture anchor material that seems to have superior resorption characteristics compared to those of other bioabsorbable suture anchor materials commonly used in arthroscopic rotator cuff repair.Trial registrationThe presented study was retrospectively registered by the commission for ethics at the Ärztekammer Nordrhein with the registration number 2016433 on January 17, 2017. All participating patients gave written consent for participation and the publication of their data.Level of evidenceIV

Fe, N co-doped graphene as a multi-functional anchor material for lithium-sulfur battery

Application of lithium-sulfur battery is still hindered by the poor cycling life, rapid capacity decay and severe self-discharge, which are mainly caused by the well-known dissolving and shuttling effects. Thus, a systematic investigation including perfect graphene, nitrogen doped graphene, iron and nitrogen co-doped graphene as anchor materials for sulfur cathodes in lithium sulfur battery are performed, in order to search new chemical functional graphene with good electrocatalysis and shuttling suppression abilities. Our results reveal that iron and nitrogen co-doped graphene monolayer is a good anchoring material, in which the LiSFeN four-membered ring structure ensures the stability of adsorption structure and allows adsorption energy of the adsorption structure to be in the suitable range. The effect of the four-membered ring mainly contributes by the strong binding between Fe and S coming from magnetic catalytic absorption. Moreover, the FeN4@graphene can promote the fully discharge of lithium polysulfides benefiting from the low decomposition energies of Li2S and Li2S2 on its surface and the catalytic effect of 3d electrons of doped iron. PDOS demonstrates essential role of iron in rending FeS bond with strong anchoring. Our research unravels anchor effect of FeN4@graphene in lithium sulfur batteries and provides invaluable theoretical guidance for high-performance lithium sulfur batteries.

Experimental Testing Suitability of the Waste Glass into the Polymer Anchor Materials Based on Epoxy Resin

This article deals with the suitable use of waste glass in polymer anchor materials based on the epoxy resin. The research focused on the effect various waste glass had in different amounts on specific anchor-material properties. Various tests were conducted such as the specification of tensile properties, thermal resistance, monitoring the temperature during a polymerization process and a pull-out test. Test results assessment led to choosing a formulation that would yield the best quality of the polymer anchor.

Influence of Temperature on the Biomechanical Stability of Titanium, PEEK, Poly-L-Lactic Acid, and β–Tricalcium Phosphate Poly-L-Lactic Acid Suture Anchors Tested on Human Humeri In Vitro in a Wet Environment

The purpose of this study was to analyze the biomechanical integrity of suture anchors of different materials (titanium, PEEK [polyether ether ketone], poly-L-lactic acid [PLLA], and β-tricalcium phosphate PLLA) and almost identical design for rotator cuff repair in human humeri positioned in a water bath at room and body temperature undergoing cyclic loading rather than single-pull or static tests. Four different anchor models (n= 6) were tested using healthy human cadaveric humeri in a water bath thermostatically regulated at 20°C and 37°C. A cyclic testing protocol was used. The maximum failure load, the system displacement, and the respective mode of failure were recorded. There were no significant differences regarding the maximum failure load values between the 20°C groups and 37°C groups for the 4 different anchor materials. The displacement values for the 20°C groups and 37°C groups also were not statistically significant. Anchor and suture dislocations were the predominant modes of failure; suture ruptures were observed in few cases. This study shows that there are no significantly relevant differences regarding the maximum failure loads and the displacement values of the tested suture anchor systems in a wet environment at 20°C or 37°C. The temperature differences do not seem to affect the modes of failure either. Titanium, PEEK, PLLA, and β-tricalcium phosphate PLLA suture anchors for rotator cuff repair can be expected-on the basis of this investigation comparing laboratory temperature with body temperature and a wet environment-to perform invivo similar to invitro testing.

Arginine Side Chains as a Dispersant for Individual Single‐Wall Carbon Nanotubes

Charged peptides and proteins disperse single-wall carbon nanotubes (SWCNTs) in aqueous solutions. However, little is known about the role of their side chains in their interactions with SWCNTs. Homopolypeptide-SWCNT systems are ideal for investigating the mechanisms of such interactions. In this study, we demonstrate that SWCNTs are individually dispersed by poly-L-arginine (PLA). The debundled SWCNTs exhibited a distinct fluorescence. The dispersibility of SWCNTs with PLA was greater than that of SWCNTs with poly-L-lysine (PLL). Molecular dynamics simulations suggest that the side chains of PLA have stronger interactions with the sidewalls of SWCNTs compared with those of PLL. The guanidinium group at the end of the side chain of an arginine residue plays an important role in the interaction with SWCNTs, likely through hydrophobic, van der Waals, and π-π interactions. PLA can be useful as a tool for the dispersion of SWCNTs and can be used to non-covalently anchor materials to SWCNTs with strong binding.

Rod-shaped Tissue Engineered Skeletal Muscle with Artificial Anchors to Utilize as a Bio-Actuator

Living muscle tissue seems to have an efficient potential as an actuator. We propose to utilize a tissue engineered skeletal muscle (TESM) as a bio-actuator by connecting to the object through artificial anchors. We designed a rod-shaped TESM with artificial anchors and fabricated it by culturing myoblasts in collagen gel for several days. The contractile ability and controllability of the TESM were confirmed by stimulating electrically. The contractions were evoked forcibly and synchronously by electrical pulses under 4.5 Hz. The electrical pulses at 8 Hz kept the contractile state. As potential anchor materials, silicone sponge and nonwoven nylon mesh were examined. The anchors made of nonwoven nylon mesh held a rod-shaped TESM for more than 3 weeks successfully, while the anchors made of silicone sponge held it for only 2-4 days and the TESM broke down at the connecting area. The mechanical endurance between the TESM and the nylon anchors was examined using our original stretching device. No damage was observed from the repeated mechanical loading at 0.5 Hz with 5 % stretch rate for 10 days. We concluded that the TESM has good potential for utilization as a bio-actuator and its abilities can be exploited by connecting it to an object through artificial anchors.

Suture Anchor Materials, Eyelets, and Designs: Update 2008

Our purpose was to evaluate recently introduced sutures and suture anchors for single pull load to failure strength and failure mode. Suture anchors were tested in fresh porcine metaphyseal cortex and cancellous troughs using an established protocol. An Instron machine applied tensile loads parallel to the axis of insertion at a rate of 12.5 mm per second until failure and mean anchor failure strengths were calculated. The mode of failure was recorded (anchor pullout, suture eyelet cut out, or suture failure). Anchors tested included the Kinsa, Kinsa RC, BioRaptor 2.3 PK, TwinFix PK FT 5.5 and 6.5, BioCleat, Healix Peek, VersaLok, BioKnotless, BioKnotless BR, Corkscrew FT III, SwiveLock C, and PEEK SutureTak. The mean cortical failure loads were as follows: Kinsa (219 N), Kinsa RC (222 N), BioRaptor 2.3 PK (172 N), TwinFix PK FT 5.5 (491 N) and 6.5 (503 N), BioCleat (218 N), Healix Peek (407 N), VersaLok (376 N), BioKnotless (249 N), BioKnotless BR (265 N), Corkscrew FT III (386 N), SwiveLock C (712 N), and PEEK SutureTak (168 N). Pullout was the predominant failure mode for the VersaLok, BioKnotless, BioKnotless BR, and BioRaptor 2.3PK anchors. Eyelet failure was the predominant failure mode for the Kinsa, Kinsa RC, BioCleat, Healix Peek, Corkscrew FT III, SwiveLock C, and PEEK SutureTak. The newer anchors showed markedly increased load to failure strengths. Two or more high-strength sutures are commonly used as well as new anchor materials (PEEK and Biocryl Rapide), new eyelet designs, and the increased use of a "knotless" concept. An anchor which fails principally by pull out at a low load to failure is at risk for creating an intra-articular loose body.

Electrochemical Investigations on Austenitic and Duplex Stainless Steels for Use as Ground Anchor Materials

Electrochemical Investigations on Austenitic and Duplex Stainless Steels for Use as Ground Anchor Materials

Bladder Neck Suspension Material Investigated in a Rabbit Model

Different principles for providing stable and durable suspension of the bladder neck and proximal urethral tissue are employed in endoscopic bladder neck suspension for female stress urinary incontinence. Six different anchor materials, some of which are currently used as tissue bolsters (anchors) for endoscopic bladder neck suspension, were implanted in the abdominal wall muscle of 45 rabbits. Tension on the anchors was measured and maintained by springs positioned between pairs of anchors. At two months evaluation, vascular graft and loops of suture retained 40% of the starting tension, while two sizes of screw anchors lost all tension. Silicone pads and kink free silicone tubing rapidly pulled through the tissue in 83% and 100% of the cases, respectively. Local tissue reaction with scar formation, physical characteristics of the anchor material (silicone, stainless steel, dacron or polypropolene) and cross sectional area of the anchor were identified as the important factors for anchor stabilization of tissue which has been repositioned under tension. (J. Urol., 142: 1361–1363, 1989)