Static Force Analysis of a 3-DOF Robot for Spinal Vertebral Lamina Milling

In order to realize robot-assisted spinal laminectomy surgery and meet the clinical needs of the robot workspace, including accuracy in human–robot collaboration, an asymmetrical 3-DOF spatial translational robot is proposed, which can realize spinal laminectomy in a fixed posture. First, based on the screw theory, the constraint screw system of the robot was established, and the degree of freedom was derived to verify the spatial translational ability of the robot. Then, a kinematic model of the robot was established, and a static force model of the robot was derived based on the kinematic model. The mathematical relationship between the external force and the joint force/torque was obtained, with the quality of all links considered in the model. Finally, we modeled the robot and imported it into ADAMS to obtain the static force simulation results of the 3D model. The force error was approximately 0.001 N and the torque error was approximately 0.0001 N∙m compared with the simulation results of the mathematical model, accounting for 1% of the joint force/torque, which is acceptable. The result also showed the correctness of the mathematical models, and provides a theoretical basis for motion control and human–robot collaboration.

Estimation of Tibiofemoral and Patellofemoral Joint Forces during Squatting and Kneeling

This study examined the differences of knee joint forces between lowering to, or rising from squat, and typical final postures of squatting and kneeling. A biomechanical model of the lower limb was configured considering large knee flexion angles, multiple floor contact points, and the soft tissue contact between the thigh and calf. Inverse dynamics were used to determine muscle and compressive joint forces in the tibiofemoral and patellofemoral joints. Data were obtained from a group of 13 male subjects by means of 3D motion capturing, two force plates, a pressure-sensitive pad, and electromyography. During lowering into the kneeling/squatting positions and rising from them, the model exhibited the anticipated high maximum forces of 2.6 ± 0.39 body weight (BW) and 3.4 ± 0.56 BW in the tibiofemoral and patellofemoral joints. Upon attainment of the static terminal squatting and kneeling positions, the forces fell considerably, remaining within a range of between 0.5 and 0.7 BW for the tibiofemoral joint and 0.9 to 1.1 BW for the patellofemoral joint. The differences of the knee joint forces between the final postures of squatting and kneeling remained on average below 0.25 BW and were significant only for the tibiofemoral joint force.

Differential Game and Simulation Study on Management Synergy of Regional Coal Mine Emergencies in China

Emergency management of coal mines requires enhanced synergy among departments, institutions, and enterprises, which means overall efficiency in management. Their synergy can effectively lower the cost of emergency management, improve the effectiveness of it, and build a strong joint force for the prevention and control of emergencies. Accordingly, this study established a synergy system for regional coal mine emergency management and analyzed the interest relationship among key stakeholders in the system. Then, it established differential game models of the management synergy, explored the selection process of the behavior strategy of each stakeholder under different situations, and provided important tools for quantitative analysis on emergency management synergy practice. Furthermore, numerical simulation was carried out to analyze the influencing factors of their decision behaviors. The research results are of great significance for the comprehension of the evolution mechanism for the emergency management synergy of coal mines, the assistance for the government in determining the optimal method in emergency management synergy, the mobilization of the stakeholders, and the improvement of the current situation of emergency management synergy of coal mines in China.

Research on Explicit and Implicit Activities in Middle School Moral Education

Middle school moral education not only plays the role of guidance, motivation, and assurance in adolescent education and school work but also has great significance in promoting social civilization and progress. In order to make moral education become more permeable, vivid, and colorful, it is required to persuade people with reason and move a man with emotion, so as to achieve a subtle effect. Also, it builds an explicit and implicit system by exploring the middle school moral education practices. The explicit moral education activities and implicit moral education activities are inextricably linked as a joint force, which makes the school moral education work quite effective. In the former one, it makes further practical and exploration activities in developing the class moral education, upholding the theme and etiquette education of “the Four Cardinal Principles”, inheriting the "benevolence" value of education and practice education, and resisting the bad information about the moral education. The latter one, it focuses on the following three aspects of implicit moral education: teachers' virtue and deeds, family education, and game activities.

Evaluation on the Effect of Fishery Insurance Policy: Evidence Based on Text Mining

As a quasi-public product, fishery insurance has become an important starting point for the construction of the modern fishery industry chain, supply chain and value chain risk management mechanism. We used visual data processing methods and text mining technology to screen policy samples. We then built a fishery insurance policy evaluation system based on the Policy Modeling Consistency (PMC) index model. We combined the PMC index score and PMC surface to quantitatively analyze the policy samples. This paper has four important findings: (1) After three adjustments and developments, the fishery insurance policy has grown in terms of initial attention, changes, and development and gradually matured. (2) A gap exists between the content of the fishing insurance policy text and the actual demand. The scoring results of the policy samples are concentrated in the acceptable range, the policy effects are not satisfactory, and the formulation of fishery insurance policies has weak links that need to be improved. (3) The consistency and effectiveness of fishery insurance policies have developed simultaneously with fishery insurance research, and the practical effects of high-quality fishery insurance policies are conducive to the development of theoretical research. (4) The policy text of fishery insurance has major problems, such as missing joint force of issuing institutions, low professionalism of the text, inadequate subdivision guidance of fishery insurance, weak social effectiveness, high dependence on financial subsidies, lack of incentive sustainability and corresponding laws and regulations and reduction in policy feasibility among others. Considering the above issues, this paper puts forward relevant policy optimization paths and safeguard measures on the basis of giving priority to greater absolute value.

Capsular ligaments provide a passive stabilizing force to protect the hip against edge loading

Aims In the native hip, the hip capsular ligaments tighten at the limits of range of hip motion and may provide a passive stabilizing force to protect the hip against edge loading. In this study we quantified the stabilizing force vectors generated by capsular ligaments at extreme range of motion (ROM), and examined their ability to prevent edge loading. Methods Torque-rotation curves were obtained from nine cadaveric hips to define the rotational restraint contributions of the capsular ligaments in 36 positions. A ligament model was developed to determine the line-of-action and effective moment arms of the medial/lateral iliofemoral, ischiofemoral, and pubofemoral ligaments in all positions. The functioning ligament forces and stiffness were determined at 5 Nm rotational restraint. In each position, the contribution of engaged capsular ligaments to the joint reaction force was used to evaluate the net force vector generated by the capsule. Results The medial and lateral arms of the iliofemoral ligament generated the highest inbound force vector in positions combining extension and adduction providing anterior stability. The ischiofemoral ligament generated the highest inbound force in flexion with adduction and internal rotation (FADIR), reducing the risk of posterior dislocation. In this position the hip joint reaction force moved 0.8° inbound per Nm of internal capsular restraint, preventing edge loading. Conclusion The capsular ligaments contribute to keep the joint force vector inbound from the edge of the acetabulum at extreme ROM. Preservation and appropriate tensioning of these structures following any type of hip surgery may be crucial to minimizing complications related to joint instability. Cite this article: Bone Joint Res 2021;10(9):594–601.

Development and Functional Testing of An Unloading Concept for Knee Osteoarthritis Patients: A Pilot Study

This paper presents a knee brace design that applies an extension moment to unload the muscles in stance phase during gait, and thereby the knee, as alternative to conventional valgus braces for knee osteoarthritis patients. The concept was tested on one healthy subject during normal gait with a prototype, which was designed to activate and deactivate in order to apply the extension moment in the stance phase only and hereby avoid any interference during the swing phase. Electromyography measurements and musculoskeletal models were used to evaluate the brace effects on muscle activation and knee compressive forces respectively. Simulations predicted an ideal reduction of up to 36%, whereas experimental tests revealed a reduction of up to 24% with the current prototype. The prototype brace also reduced the knee joint force impulse up to 9% and EMG peak signal of the vasti muscles with up to 19%. Due to these reductions on a healthy subject, this bracing approach seem promising for reducing knee loads during normal gait. However, further clinical experiments on knee osteoarthritis patients are required to evaluate the effect on both pain and disease progression.

Four-channel sEMG for Elbow Load Recognition

In order to help patients after surgery to carry out reasonable rehabilitation training, avoid joint adhesions and movement disorders, the relationship between surface electromyograph (sEMG) signal changes and the size of the patient ' s joint force in the process of rehabilitation exercise was studied, hoping to use the relationship between them to redesign the control mode of the rehabilitation robot, and a method was proposed to identify the size of the elbow load based on wavelet packet. Firstly, s EMG signals of human elbow joint during stretching and bending under different loads were collected by 4-channel surface electromyography. Then, the wavelet packet decomposition method was used to obtain the feature vector composed of energy(E), variance(VAR) and mean absolute value(MAV) of wavelet packet coefficient. Finally, the improved support vector machine ( ISVM), BP neural network and RBF neural network were used for pattern recognition of three different forces. The experimental results show that the change of sEMG signal is indeed related to the size of joint force. It is feasible to identify the load of s EMG signal.

Biomechanical Analysis of Cervical Artificial Disc Replacement Using Cervical Subtotal Discectomy Prosthesis

Background: Anterior cervical discectomy and fusion (ACDF) sacrifices segmental mobility, which can lead to the acceleration of adjacent segment degeneration. The challenge has promoted cervical artificial disc replacement (CADR) as a substitute for ACDF. However, CADR has revealed a series of new issues that are not found in ACDF, such as hypermobility, subsidence, and wear phenomenon. This study designed a cervical subtotal discectomy prosthesis (CSDP) consisting of a cervical disc prosthesis structure (CDP structure), cervical vertebra fixation structure (CVF structure), link structure, and locking screw, aiming to facilitate motion control and reduce subsidence. The aim of this study was to assess the biomechanics of the CSDP using finite element (FE) analysis, friction-wear test, and non-human primates implantation study.Study Design: For the FE analysis, based on an intact FE C2-C7 spinal model, a CSDP was implanted at C5-C6 to establish the CSDP FE model and compare it with the Prestige LP prosthesis (Medtronic Sofamor Danek, Minneapolis, MN, United States). The range of motion (ROM), bone-implant interface stress, and facet joint force were calculated under flexion extension, lateral bending, and axial rotation. In addition, CSDP was elevated 1 mm to mimic an improper implantation technique to analyze the biomechanics of CSDP errors in the FE model. Moreover, the friction-wear test was conducted in vitro to research CSDP durability and observe surface wear morphology and total wear volume. Finally, the CSDP was implanted into non-human primates, and its properties were evaluated and verified by radiology.Results: In the FE analysis, the ROM of the CSDP FE model was close to that of the intact FE model in the operative and adjacent segments. In the operative segment, the CSDP error FE model increased ROM in flexion extension, lateral bending, and axial rotation. The maximum stress in the CSDP FE model was similar to that of the intact FE model and was located in the peripheral cortical bone region. The facet joint force changes were minimal in extension, lateral bending, and axial rotation loads in CSDP. In the friction-wear test, after the 150-W movement simulation, both the CVF-link-junction and the CDP-link-junction had slight wear. In the CSDP non-human primate implantation study, no subsidence, dislocation, or loosening was observed.Conclusion: In the FE analysis, the biomechanical parameters of the CSDP FE model were relatively close to those of the intact FE model when compared with the Prestige LP FE model. In terms of CSDP error FE models, we demonstrated that the implantation position influences CSDP performance, such as ROM, bone-implant interface stress, and facet joint force. In addition, we performed a friction-wear test on the CSDP to prove its durability. Finally, CSDP studies with non-human primates have shown that the CSDP is effective.

THE IMPLICATION OF TIKTOK APPLICATION AS A MEDIA FOR THE DISSEMINATION OF TRI HITA KARANA'S TEACHINGS DURING THE COVID-19 PANDEMIC

<span class="s17"><span class="bumpedFont15">The popularity of the </span></span><span class="s26"><span class="bumpedFont15">TikTok</span></span><span class="s17"><span class="bumpedFont15"> application in the current era needs to be directed positively to spread the teachings of </span></span><span class="s26"><span class="bumpedFont15">Tri Hita Karana</span></span><span class="s17"><span class="bumpedFont15">. This is because </span></span><span class="s26"><span class="bumpedFont15">Tri Hita Karana's</span></span><span class="s17"><span class="bumpedFont15"> teachings are able to restore the balance of the world to face the </span></span><span class="s26"><span class="bumpedFont15">COVID</span></span><span class="s17"><span class="bumpedFont15">-19 pandemic. </span></span><span class="s17"><span class="bumpedFont15">Reflecting on this, researchers are interested in examining more deeply the implications of the </span></span><span class="s26"><span class="bumpedFont15">TikTok</span></span><span class="s17"><span class="bumpedFont15"> application as a medium for spreading the teachings of </span></span><span class="s26"><span class="bumpedFont15">Tri Hita Karana</span></span><span class="s17"><span class="bumpedFont15"> during the </span></span><span class="s26"><span class="bumpedFont15">COVID</span></span><span class="s17"><span class="bumpedFont15">-19 pandemic. In this study, several problem formulations were formulated, namely related to the popularity of the </span></span><span class="s26"><span class="bumpedFont15">TikTok</span></span><span class="s17"><span class="bumpedFont15">application, the importance of the teachings of </span></span><span class="s26"><span class="bumpedFont15">Tri Hita Karana</span></span><span class="s17"><span class="bumpedFont15">during the </span></span><span class="s26"><span class="bumpedFont15">COVID</span></span><span class="s17"><span class="bumpedFont15">-19 pandemic, and the implications of the </span></span><span class="s26"><span class="bumpedFont15">TikTok</span></span><span class="s17"><span class="bumpedFont15"> application as a medium for spreading the teachings of </span></span><span class="s26"><span class="bumpedFont15">Tri Hita Karana</span></span><span class="s17"><span class="bumpedFont15">. Using this type of qualitative research, with a visual ethnographic approach, the results of this study indicate the implications of the </span></span><span class="s26"><span class="bumpedFont15">TikTok</span></span><span class="s17"><span class="bumpedFont15"> application as a medium for disseminating the teachings of </span></span><span class="s26"><span class="bumpedFont15">Tri Hita Karana</span></span><span class="s17"><span class="bumpedFont15">, which have advantages in terms of making unique videos, as well as in terms of effective and efficient video promotion to provide addition</span></span><span class="s17"><span class="bumpedFont15">al insights to viewers about </span></span><span class="s17"><span class="bumpedFont15">teachings of </span></span><span class="s26"><span class="bumpedFont15">Tri Hita Karana</span></span><span class="s17"><span class="bumpedFont15"> as a joint force to face the </span></span><span class="s26"><span class="bumpedFont15">COVID</span></span><span class="s17"><span class="bumpedFont15">-19 pandemic.</span></span>