Varicose vein treatments range from conventional surgical ligation and sclerotherapy to venous closure using biological adhesives. However, considering ease of procedure, recovery time, and cosmetic outcomes like minimal scarring, minimally invasive techniques employing lasers or radiofrequency are preferred. The efficacy of these methods heavily relies on clinician expertise and ultrasound imaging, with manual catheter retraction during cauterization presenting challenges, such as overlapping or untreated areas, especially in long vessels exceeding 1 meter, leading to increased procedure time and operator fatigue. To address these issues, we propose an automated catheter procedure for varicose veins. This system features a handpiece for energy generation control (laser, radiofrequency) operated near the clinician for convenience. We designed a pullback system that enables constant speed rotation and forward/backward movements of the catheter without moving the handpiece. Through handpiece operation, the catheter rotates at a set speed, and a roller-driven pullback action occurs as it winds on a reel, expanding the diameter of the reel for retraction while remaining stationary. Conversely, reducing the diameter of the reel facilitates forward movement. The length adjustment of the catheter based on winding turns on the reel makes it adaptable for various vascular procedures, enhancing the procedural accuracy and operator convenience.

Chronic wounds necessitate periodic treatment and management due to their potential for serious complications. Recently, ultrasonic mist therapy has been introduced to treat chronic wounds efficiently. This therapy requires a noncontact spraying method to prevent side effects such as bacterial infections and pain. Therefore, research is needed on a spray nozzle tip that can effectively transmit ultrasonic energy to the wound target with misted cleaning solution mobility in a specific direction and at an appropriate speed. The performance of the nozzle tip is greatly affected by the flow characteristics inside it. Computational fluid dynamics (CFD) is a powerful tool to analyze these characteristics in detail. The behavior of the mist was analyzed in a simulation based on discrete phase model methodology in an unsteady state. Valid design parameters enabling noncontact cleaning were determined by setting the design parameters of the nozzle tip`s internal flow path and measuring the spraying speed of the mist using CFD analysis. Through the simulation results, information on the sprayed skin surface and spray characteristics are measured. Lastly, we present a nozzle tip design guide optimized for ultrasonic mist therapy.

It is known that the low-intensity sound stimulation really affect to grow the cell. The cellular growth mechanism, however, does not been clearly identified even the effect on the low-intensity sound stimulation. The purpose of this study is to investigate the effect of low-intensity sound stimulation on the alveolar UC-MSC proliferation. Before the low-intensity sound stimulation is applied, the UC-MSC are cultured for 24 hours to facilitate their attachments. The cells are divided into two groups. And each was exposed to a medium with or without the low-intensity ultrasound stimulation at 71㏈ intensity level. The UC-MSC are again divided into three treatment groups of group 1, 2, and 3 and exposed to a frequency at 50㎐, 100㎐, and 1000㎐, respectively. In the results, it is investigated that the growth rates of UC-MSC for the stimulated groups were higher than those of control groups. In 1000㎐ frequency, the number of UC-MSC cell is significantly higher than control groups (p＞0.05). We would put the hypothesis that the cell growth could be enhanced by an appropriate low-intensity sound stimulation

Up to now, process design of multistage profile drawing from initial round material is performed through trial-and-error based on experience of industrial experts. This means the increase in production cost and excessive time consuming. In this study, process design program was developed for multistage profile drawing from initial round material. The program was made using VisualLISP. Therefore, the program can be operated by AutoCAD program. In order to verify the effectiveness of the program, two stage profile drawing process for producing heavy duty guide rail was design by using the program. In addition FE analysis and profile drawing experiment were performed. As a result, the program can be used in order to design profile drawing process design.

In general, spinal fusion surgery takes pressure off the pain induced nerves , by restoring the alignment of the spine. Therefore spinal fixation system is used to maintain the alignment of spine. In this study, a biomechanical study was performed comparing the SROM(Spinal Range Of Motion) of three types of system such as Rigid, Dynesys, and Fused system to analyze the behavior of spinal fixation system inserted in vertebra. Dynesys system, a flexible posterior stabilization system that provides an alternative to fusion, is designed to preserve inter-segmental kinematics and alleviate loading at the facet joints. In this study, SROM of inter-vertebra with spinal fixation system installed in the virtual vertebra from L4 to S1 is estimated. To compare with spinal fixation system, a simulation was performed by BRG. LifeMOD 2005.5.0 was used to create the human virtual model of spinal fixation system. Through this, each SROM of flexion, extension, lateral bending, and axial rotation of human virtual model was measured. The result demonstrates that the movement of Dynesys system was similar to normal condition through allowing the movement of lumbar.

In this study, we performed the biomechanical analysis of cervical plate systems by using a computer simulation based on finite element method to derive reliable model by analysis of design variables and fatigue behavior. To simulate the cervical spine movement in-vivo state by surgery, we modeled the cervical plate system which consisted of screws, rings, rivets, and plate and Ultra High Molecular Weight Polyethylene (UHMWPE) Block. The experiment of cervical plate system followed the ASTM F1717 standards that covered the materials and methods for the static and fatigue testing. The result of computer simulation is compared with experimented test. We expected this study is to derive reliable results by analysis of design variables and fatigue behavior for developing a new model.

Hypoplastic left heart syndrome is currently the most lethal cardiac malformation of the newborn infant. Survival following a Norwood operation depends on the balance between systemic and pulmonary blood flow, which is highly dependent on the fluid dynamics through the interposition shunt between the two circulations. The purpose of this study is an optimization of the systemic-to-pulmonary artery shunt. In this study, We used computational fluid dynamic(CFD) models to determine the velocity profile in a systemic-to-pulmonary artery shunt and suggested a simplified method of calculating the blood flow in the shunt based on Ultrasound systems. We analyzed the flow characteristic variations and oscillatory shear index(OSI) due to the anastomosis angle and shunt diameter changing. Four different CFD models were constructed with the shunt sizes ranging from 3 to 3.5㎜. The angle between the brachiocephalic trunk(BCT) and the shunt were 30° and 45°, respectively. When the diameter is 3.0 ㎜, the oscillatory shear index decreased by 1.2% at 30° as opposed to at 45°. When the diameter is 3.5 ㎜, it increased by 18% more at 30° as opposed to at 45°. When the joint angle is 30° and the diameter is 3.0 ㎜, the oscillatory shear index decreased by 4.1% in comparison with the 3.5 ㎜ diameter. When the angle is 45° and the diameter is 3.0 ㎜, the index increased by 14.6% in comparison with the 3.5 ㎜ diameter.

In this study, we performed finite element analysis for the design of a medical centrifuge and two-types of centrifuge were compared with each other. The types of centrifuge are 2-arm straight type and 3-arm type. Structural analysis was done with respect to the change of the rotational speed of the rotor of a centrifuge. When the rotor of centrifuge was rotated, the von Mises stress of 2-arm straight type-rotor was compared with the von Mises stress of 3-arm type. The margin of safety was estimated from the result. We found the critical speed of centrifuge from the campbell diagram by modal analysis.

In this paper, results are presented by non linear finite element simulations in order to analy the interactions between the stent and artery or plaque. Maximum of von Mises stress was calculated in the contacting areas between the stent and the artery. The simulated results show that the distal end of stent, which tilts after expansion, may injure the artery wall. In conclusion, this study may help designing new stents.

A Femur is the longest and largest bone which supports body in human musculoskeletal structure. Therefore, it may cause heavy loss of blood when it is suffered by a simple or complex fracture, and the complication is very dangerous with a possibility of severe tissue damage.
In this study, the femoral cancellous angle change is estimated in order to design the Korean femoral IM nail. Generally, it is various in the size and curvature of femoral cancellous bone depending on patient's body dimension. Therefore surgeon has difficulty in fitting this femoral IM nail to the patient in the surgical procedure. In our study, we tries to estimate femoral lateral curve angle with more precise method based on CT image of the femur and utilize this information on the design of femoral IM nail for Korean patients.

The purpose of this study is to design electrical stimulation system for stroke patients with pharyngeal dysfunction(dysphagia). Dysphagia is that the food has trouble in passing to the mouth from the stomach. Although we have many treatment methods for dysphagia, electrical stimulation system will be useful for stroke patients having dysphagia. Electrical stimulation system can be divided into body and electrodes. The body stimulation is composed to frequency counter, time control and current measurement part. These parts are to control the frequency, stimulating time and current intensity. And they can be variable according to the patient's clinical assessment. The electrode plays a role to deliver the current from the system to the muscle. Also the position of the electrode can be variable according to the treatment method. We performed the clinical experiment with stroke patients who had swallowing disorder. The video fluoroscopy was used for the observation. From the result of clinical experiment based on electrical stimulation, we expected that the dysfunction(in pharynx) level of the patient could be improved. However we could not have enough effectiveness of the treatment because of the number of patients, patient's adaptation and treatment period. We will design the optimized electrical stimulation system based on enough clinical experiment in the future.

In this study, ground reaction force(GRF), absolute symmetry index(ASI) and coefficient of variation(CV) of fixed, single-axis and multi-axis prosthetic ankle assemblies were investigated to show the biomechanical evaluation for above knee amputees. In the experiments, 37 normal male volunteers, two male and two female AK amputees were tested with fixed, single-axis and multi-axis prosthetic ankle assembly. A gait analysis was carried out to derive the ratio of GRF to weight as the percentage of total stance phase for ten points. The results showed that fixed-axis ankle was superior to the other two ankle assemblies for the characteristic of forwarding and breaking forces. Multi-axis ankle was relatively superior to the other two ankle assemblies for gait balancing and movement of the center for mass. single-axis ankle was relatively superior to the other two ankle assemblies for CV and ASI of GRF.

In this study, for a safety assessment of wheelchair occupant in frontal and side impact of wheelchair loaded vehicle, a sled impact test was perfomed. Each test was carried out total 6 times, by using Hybrid Ⅲ 50th-percentile male dummy in light weight and electric wheelchair. We estimate MC(Motion Criteria), CIC(Combined Injury Criteria), HIC(Head Injury Criteria), HNIC(Head and Neck Injury Criteria) based on measured data. Through this study, we make an assessment of risk analysis of wheelchair occupant and wheelchair. Through this study, safety standard of wheelchair is to be evaluated.