• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.25 no.2
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• pp.147-162
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• 2022

Purpose: To design a prospective study on endovascular closure of congenital portosystemic shunts. The primary endpoint was to assess the safety of endovascular closure. The secondary endpoint was to evaluate the clinical, analytical and imaging outcomes of treatment. Methods: Fifteen patients (age range: 2 days to 21 years; 10 male) were referred to our center due to congenital portosystemic shunts. The following data were collected prior to treatment: age, sex, medical history, clinical and analytical data, urine trimethylaminuria, abdominal-US, and body-CT. The following data were collected at the time of intervention: anatomical and hemodynamic characteristics of the shunts, device used, and closure success. The following data were collected at various post-intervention time points: during hospital stay (to confirm shunt closure and detect complications) and at one year after (for clinical, analytical, and imaging purposes). Results: The treatment was successful in 12 participants, migration of the device was observed in two, while acute splanchnic thrombosis was observed in one. Off-label devices were used in attempting to close the side-to-side shunts, and success was achieved using Amplatzer™ Ductus-Occluder and Amplatzer™ Muscular-Vascular-Septal-Defect-Occluder. The main changes were: increased prothrombin activity (p=0.043); decreased AST, ALT, GGT, and bilirubin (p=0.007, p=0.056, p=0.036, p=0.013); thrombocytopenia resolution (p=0.131); expansion of portal veins (p=0.005); normalization of Doppler portal flow (100%); regression of liver nodules (p=0.001); ammonia normalization (p=0.003); and disappearance of trimethylaminuria (p=0.285). Conclusion: Endovascular closure is effective. Our results support the indication of endovascular closure for side-to-side shunts and for cases of congenital absence of portal vein.

• Journal of Biomedical Engineering Research
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• v.45 no.1
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• pp.43-48
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• 2024

The prevalence of obesity and its complications is steadily increasing worldwide. It is essential to understand cellular level metabolism and microenvironment to treat diseases related to lipid metabolism. Mechanical loading can activate signaling pathway by stimulating cells, especially vibration loading known to inhibit adipogenesis, so it has been studied as a treatment for obesity. Also, vibration loading can affect the inside of the human body non-invasively. Another clue to reducing adipose tissue is browning, which means that white adipocytes changes to brown adipocyte. In this study, we design and developed a device that that can control cell-cell contact, and vibration simulation device. Using these two devices, we investigated responses of cells to vibration loading. Protein expression associated with browning and adipogenesis were analyzed. In conclusion, vibration loading can be transmitted through cell contact and loading applied to the cells can induce browning and inhibit adipogenesis of preadipocytes. These results suggest the possibility that vibrations could be a treatment for obesity.

• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.121-126
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• 2003

The purpose of this work was to assess and quantify whether the beneficial effects in long-term gas exchange at exciting frequency were obtained at different frequencies as well and then to develop a vibrating intravascular lung assist device(VIVLAD), for Patients suffering from acute respiratory distress syndrome(ARDS) or chronic respiratory problems. We investigate the optimal condition of the frequency band excited with new vibrator at state of limit hemolysis when blood hemolysis came to through a membrane vibration action. The experimental design and procedures were given for a device used to assess the effectiveness of membrane vibrations. Quantitative experimental measurements were performed to evaluate the performance of the device . and to identify membrane vibration dependence on blood hemolysis. We developed an analytical solution for the hydrodynamics of flow through a bundle of sinusoidally vibrated hollow fibers that is used to provide some insight into how wall vibrations might enhance the performance of the VIVLAD. In the result, it was measured that the effect of various excited frequencies in gas transfer rate and hemolysis from the maximum gas transfer rate at no vibration when the maximum gas transfer rates showed at module type 6, module type 6 consisted of 675 hollow fiber membranes The maximum oxygen transfer rate was caused by the occurrence of maximum amplitude and transfer of vibration to hollow fiber membranes when it was excited by the frequency band of 7Hz at each blood flow rate. because this frequency became the End mode resonance frequency of the flexible in blood flow. Also, when module type 6 was excited at an excited frequency of 7Hz. blood hemolysis was low. Therefore, we decided that the limit of hemolysis frequency is 7Hz . because maximum amplitude occurred at this frequency.

• Journal of Biomedical Engineering Research
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• v.30 no.6
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• pp.482-488
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• 2009

Conventional devices for transanal endoscopic microsurgery that are currently used clinically for intestine or rectal cancer patients have 40 mm external diameter of rectoscope tube - induces anal damage and long-term postoperative pain for small-sized patients. In this paper, we designed rectum and rectoscope models and calculated the changing trends of operation area of the surgical tools in accordance with the step-by-step variation of design parameters of the rectoscope tube - external diameter, axial length, and distal angle. Using the results of computer simulation, we suggested an optimal set of design parameters that minimizes external diameter of the rectoscope tube and at the same time, maintains similar operation area of the surgical tools compared with commercialized devices (${\geq}\;4274.7mm^2$). The results of the simulation showed that the optimal design parameters were 35 mm external diameter, 100 mm axial length, and $45^{\circ}$ distal angle of the rectoscope tube. This result can be applied to the development of endoscopic microsurgery device that can minimize side effects to the intestine or rectal cancer patients.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.303-311
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• 2013

This research deals with the analysis and design of a driving mechanism for an automatic pneumatic drug injector, which can precisely control the injection volume using a relatively simple friction-driven mechanism, without any complicated control system. Through a dynamic analysis, the effects of the design parameters of the driving mechanism associated with the geometry, spring stiffness, and fiction are analyzed, and the results are reflected in a proto-type drug injector design, which is under development for mass production. A test is performed to assess the durability of the mechanism for up to one million operations, and comparison of its displacement after one million operations, verifies the mechanism's durability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.9
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• pp.982-989
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• 2009

Parallel Kinematic Mechanism (PKM) is a device to perform the various motion in three-dimensional space and it calls for six degree of freedom. For example, Parallel Kinematic Mechanism is applied to machine tools, medical equipments, MEMS, virtual reality devices and flight motion simulators. Recently, many companies have tried to develop new Parallel Kinematic Mechanism in order to improve the cycle time and the precisional tolerance. Parallel Kinematic Mechanism uses general universal joint and spherical joint, but such joints have accumulated tolerance problems. Therefore, it causes position control problem and dramatically life time reduction. This paper focused on the rolling element to improve sliding precision in new sliding ball joint development. Before the final design and production, it was confirmed that new sliding ball joint held a higher load and a good geometrical structure. FEM analysis showed a favorable agreement with tensile and compressive testing results by universal testing machine. In conclusions, a new sliding ball joint has been developed to solve a problem of accumulated tolerance and verified using tensile and compressive testing as well as FEM analysis.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.461-470
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• 2007

Human can learn how to shape their brain electrical activity in a desired direction through continuous feedback of the electroencephalogram (EEG), and this technique is known as Neurofeedback (or EEG biofeedback), which has been used since the late 1960s in clinical applications. In this study, a portable wireless EEG (named wEEG) has been designed and implemented, which consists of a mobile station (a wireless two-channel EEG acquisition device) and a base station (a bridge between mobile station and computer). Moreover, a SensoriMotor Rhythm (SMR) training system was also implemented with the wEEG for enhancing attention with virtual environment. Experiment results based on 16 volunteers' (8 females and 8 males, average age is $27{\pm}4$) were reported in this paper. The results show that the SMR ratio of 87.5% subjects increased about 0.7% in training status than that in the stable status. With the proposed system, many training protocol scan be designed easily and can be done at home in our daily life conveniently. Additionally, the proposed system will be useful for disabled and aged people.

• Journal of Biomedical Engineering Research
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• v.32 no.1
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• pp.32-36
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• 2011

The insufflators in endoscopic surgery supply carbon dioxide to make the air-filled cavity in the abdomen. It contains many kinds of pneumatic and electronic parts and they are connected with the air tubes and electrical wires. The printed circuit boards (PCB) perform wiring, holding and cooling tasks in electronic systems. In this study, the PCB is used as the air channel for insufflators to decrease the cost, volume, and the malfunction according to aging of the device. Three layers of PCB made of FR4 are combined with prepreg as adhesive which has the internal airway channel according to the design. By mounting the pressure sensors and valves, the PCB based fluidic system is implemented. After calibration of flow sensor, the flow rate of the gas also can be measured. The climate test, temperature test, and biocompatibility test showed this idea can be used in insufflators for laparoscopic surgery.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.361-363
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• 2013

본 논문에서는 최근 스마트 헬스케어가 보건의료서비스에 특화시켜 환자와 의사가 직 간접적으로 진료를 할 수 있게끔 하는 스마트폰 환경에서의 원격진료 서비스가 부각됨에 따라 유무선 통신 인프라를 기반으로 노인, 만성질환자, 회복중인 환자나 수술 후 환자 그리고 일반인 등이 일상생활을 하면서 불편하거나, 거추장스럽지 않게 신체 정보를 측정하고 건강상태의 변화에 대한 전문가의 진단을 즉각적으로 제공하기 위해 Bluetooth HDP(Health Device Profile)을 통해 IEEE11073 PHD 표준 기반의 홈 헬스케어 의료기기 연결성을 보장하며, HL7 CDA 기반의 정보 전달 구조로 의료진뿐만 아니라 다양한 스마트 앱 어플리케이션 간의 융합을 가능하게 하는 스마트 헬스케어 솔루션을 설계하고자 한다.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.11-18
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• 2016

Today, wearable technology products are used in a wide range of consumer, healthcare, bio-medical, and industrial applications. The market for wearable technology products is expected to increase dramatically over the next several years. In addition, concerns for safety, performance and reliability of wearable products keep increasing and will be essential for widespread acceptance in the marketplace. Wearable smart devices, which are generally in contact with the human body and skin, are exposed to the risk of the electric shock, burn, and explosion. Therefore, the standardization of wearable devices in terms of human safety and reliability should be very important. Furthermore, the development of test method and test certification of the wearable products will be one of the key technology for mass production. Such standardization and certification will help consumers to choose the safest and best quality wearable devices and allow manufacturers to prove the safety and quality of their products, thereby helping them to gain a competitive technology. This paper discusses the current status of the wearable smart devices as well as the standardization and test certification applicable to wearable technology products.