205 results on '"Young-Keun Lee"'
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2. Thermal analysis and experimental verification of permanent magnet synchronous motor by combining lumped-parameter thermal networks with analytical method
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Manh-Dung Nguyen, Jong-Hyeon Woo, Hyo-Seob Shin, Young-Keun Lee, Hoon-Ki Lee, Kyung-Hun Shin, Anh-Tuan Phung, and Jang-Young Choi
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Physics ,QC1-999 - Abstract
This study presents an approach to calculating the temperature increase in the internal components of permanent magnet synchronous machines by applying lumped-parameter thermal networks and analytical methods. Accordingly, the thermal equivalent circuit method is employed to obtain the temperatures of the machine’s internal components. Furthermore, this analytical method predicts the temperature distribution in the slot area. The 24/6 prototype was used to evaluate the proposed model by comparing the calculated and finite element method simulation.
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- 2023
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3. A study on the shaft stability and prediction of electromagnetic and NVH characteristics of permanent magnet synchronous machine according to the different pole/slot combination
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Young-Keun Lee, Tae-Kyoung Bang, Seong-Tae Jo, Hoon-Ki Lee, Yong-Joo Kim, Sung-Ho Lee, Min-Seok Kim, and Jang-Young Choi
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Physics ,QC1-999 - Abstract
In this study, electromagnetic noise sources of permanent magnet synchronous motors with 8-pole 9-slot and 12-slot fractional slot concentrated windings were analyzed through finite element analysis, and the radiated noise/vibration levels were compared through structural-acoustic analysis. In addition, the stability of the rotational shaft generated vibration was analyzed. Electromagnetic noise sources are classified into cogging torque, torque ripple, and unbalanced magnetic force. The effect of electromagnetic noise sources on vibration/noise was analyzed in the frequency domain through the electromagnetic-mechanical coupling analysis. The noise level was compared to the electromagnetic noise source characteristics for each frequency using the waterfall diagram, and additional vibration due to mechanical resonance was analyzed using critical speed analysis while taking the rotor's bearing stiffness into account.
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- 2023
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4. Optimal design of high-speed permanent magnet synchronous generator based on NSGA-II considering mechanical properties
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Seong-Tae Jo, Woo-Hyeon Kim, Jeong-In Lee, Tae-Kyoung Bang, Young-Keun Lee, Hoon-Ki Lee, Kyung-Hun Shin, and Jang-Young Choi
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Physics ,QC1-999 - Abstract
Although the finite element method (FEM) is highly reliable, it is time-consuming and expensive, for example, substantial computing costs are incurred for coupled analysis while considering the mechanical and electromagnetic properties. Therefore, in this paper, a high-speed permanent magnet generator's electromagnetic and stress characteristics have been mathematically derived, and the optimal point is selected based on NSGA-II. The objective functions are power density and efficiency, with the constraints being the current density, slot fill factor, core saturation, voltage limit, and rotor safety factor. The method presented in this study was verified via FEM analysis and experimental results of the optimal model.
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- 2023
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5. Treatment of subacute/chronic ECU tendinopathy using wrist arthroscopy and open surgical repair
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Young-Keun Lee MD PhD
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Orthopedic surgery ,RD701-811 - Abstract
Purpose To report the arthroscopic and clinical findings of patients with extensor carpi ulnaris (ECU) tendinopathy treated with wrist arthroscopy and open surgical repair. Methods We retrospectively reviewed the medical records of seven patients with chronic ECU tendinopathy who were treated with diagnostic wrist arthroscopy and open surgical repair between 2010 and 2017. Seven cases diagnosed with ECU tendinopathy had undergone open procedure for the ECU tendinopathy, as well as wrist arthroscopy in the same session. Any pathology of the triangular fibrocartilage complex (TFCC) diagnosed by wrist arthroscopy were treated simultaneously with open procedure for the ECU tendinopathy. The functional outcome was evaluated by comparing the preoperative and final follow-up values of range of motion (ROM), grip strength, visual analog scale (VAS) for pain, modified Mayo wrist score and quick disabilities of the arm, shoulder, and hand (DASH) score. Results TFCC tears were identified in four patients of which repair was performed concomitantly. The average follow-up period was 39 months (range, 25–49 months). At the final follow-up, all the outcomes including average VAS score (6.4→1), the ROM (173→192°), quick DASH score (42.5→18.2), and modified Mayo wrist score (48.6→79.3) improved significantly. Conclusion When treating patients with ECU tendinopathy, the possibility of TFCC combined injury should always be considered. If surgical treatment is planned, we suggest a wrist arthroscopy for more accurate diagnosis an intra-articular pathology, particularly for patients whose MRI findings suggest a degenerative tear or degeneration at the periphery of the TFCC. Additionally, if ECU and DRUJ stability is obtained by repair or reconstruction of the concurrent pathologies in the ECU subsheath, TFCC and other intra-articular structures, the results will be favorable.
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- 2022
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6. Artificial intelligence-based classification of bone tumors in the proximal femur on plain radiographs: System development and validation
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Chan-Woo Park, Seong-Je Oh, Kyung-Su Kim, Min-Chang Jang, Il Su Kim, Young-Keun Lee, Myung Jin Chung, Baek Hwan Cho, and Sung-Wook Seo
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Medicine ,Science - Abstract
Purpose Early detection and classification of bone tumors in the proximal femur is crucial for their successful treatment. This study aimed to develop an artificial intelligence (AI) model to classify bone tumors in the proximal femur on plain radiographs. Methods Standard anteroposterior hip radiographs were obtained from a single tertiary referral center. A total of 538 femoral images were set for the AI model training, including 94 with malignant, 120 with benign, and 324 without tumors. The image data were pre-processed to be optimized for training of the deep learning model. The state-of-the-art convolutional neural network (CNN) algorithms were applied to pre-processed images to perform three-label classification (benign, malignant, or no tumor) on each femur. The performance of the CNN model was verified using fivefold cross-validation and was compared against that of four human doctors. Results The area under the receiver operating characteristic (AUROC) of the best performing CNN model for the three-label classification was 0.953 (95% confidence interval, 0.926–0.980). The diagnostic accuracy of the model (0.853) was significantly higher than that of the four doctors (0.794) (P = 0.001) and also that of each doctor individually (0.811, 0.796, 0.757, and 0.814, respectively) (PConclusions The AI-based model demonstrated high performance in classifying the presence of bone tumors in the proximal femur on plain radiographs. Our findings suggest that AI-based technology can potentially reduce the misdiagnosis of doctors who are not specialists in musculoskeletal oncology.
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- 2022
7. Analysis and Comparison of Permanent Magnet Synchronous Motors According to Rotor Type under the Same Design Specifications
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Woo-Sung Jung, Hoon-Ki Lee, Young-Keun Lee, Su-Min Kim, Jeong-In Lee, and Jang-Young Choi
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SPMSM ,IPMSM ,bar-type ,electromagnetic characteristics ,comparative analysis of characteristics ,back electromotive force (back EMF) ,Technology - Abstract
A surface-mounted permanent magnet synchronous motor (SPMSM) is an electric motor with a simple magnetic circuit design, fast responsiveness, linear torque–current characteristics, speed–voltage characteristics, and constant operating speed. SPMSMs use only magnetic torque; however, interior PMSMs (IPMSMs) have high power densities because they can use reluctance torque. In addition, when flux-weakening control is used, the operating range is wide compared with the SPMSM. This study presents a comparative analysis of the characteristics of SPMSM and bar-type IPMSM. Characteristic analyses are performed by setting the same stator shape, rated speed, number of turns, winding specifications, voltage limit, and magnet usage in a pole/slot combination of six poles and 27 slots. Next, we compare the no-load back electromotive force, cogging torque, and loss characteristics, and perform a characteristic analysis of each model while satisfying the design specifications. No-load and load tests are performed using a back-to-back system. The results of the analysis and experimental results are in good agreement, and the reliability of the analysis results is guaranteed. The SPMSM is approximately 8.5% superior to the IPMSM in terms of core loss, and the eddy current loss is greater than that of the IPMSM.
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- 2023
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8. Multi-Objective Optimal Design of SPMSM for Electric Compressor Using Analytical Method and NSGA-II Algorithm
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Seong-Tae Jo, Woo-Hyeon Kim, Young-Keun Lee, Yong-Joo Kim, and Jang-Young Choi
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analytical method ,NSGA-II ,pareto optimization ,SPMSM ,Technology - Abstract
In contrast to internal combustion engine vehicles, electric vehicles (EVs) obtain the power required for the compressor of air conditioning system from an electric source. Therefore, an optimal design for electric motor, the main component of an electric compressor, is essential for improving EV mileage. A multi-objective optimal design is required because the characteristics of the motor are in a trade-off relationship with each other. When the finite element method (FEM) is used, multi-objective optimal designs for the motor take a significant amount of time because of the diversity analyses required for the optimal-model search. To solve this problem, in this study, a multi-objective optimal design method of an SPMSM for an EVs air conditioner system compressor was proposed and applied using the NSGA-II and an analytical method. The validity of the proposed method was confirmed by comparing the characteristics of the optimal design model with those of the initially designed model.
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- 2022
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9. Electromagnetic and Mechanical Analysis and Measurements of Interior Permanent Magnet Motors Based on Equivalent Magnetic Circuit Method
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Young-Keun Lee, Tae-Kyoung Bang, Seong-Tae Jo, Yong-Joo Kim, Kyung-Hun Shin, and Jang-Young Choi
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equivalent magnetic circuit ,magnetic field analysis ,permanent magnet ,interior permanent magnet motor ,stress analysis ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
This paper is about the magnetic field analysis of an interior permanent magnet motor (IPM motor) by using the equivalent magnetic circuit method (EMC method), which requires a small amount of computation time compared with the finite element method (FEM). IPM motors have a specific shape of rotor in which the permanent magnets are embedded. Therefore, in the bridge region, the magnetic saturation is generated due to the shape of the permanent magnet, which affects the magnetic flux density distribution in the air gap and the characteristics of the IPM motor. Thus, to design an IPM motor, the magnetic saturation effects should be considered along with the rotor shape. In addition, because the rotor of the IPM rotates at a high speed directly in connection with the load, the stress generated from the rotor must be stably distributed. Consequently, according to the rotor shape characteristics of the IPM, the stress is concentrated in the thin bridge region during high-speed rotation. When the stress generated in the bridge region exceeds the yield stress of the rotor iron core material, the bridge part is destroyed. Therefore, it is important to analyze the stress that occurs in the rotor during high-speed rotation in the rotor design stage of the IPM. In this study, we analyzed the magnetic field characteristics of an IPM motor using its equivalent magnetic circuit while considering the magnetic saturation in the bridge region. The stability of the rotor was determined by presenting a safety factor based on the maximum stress generated at the rotor for each speed. We derived the stator natural frequency to evaluate the resonance possibility between the electrical frequency and the stator natural frequency. Finally, the validity of the constructed equivalent magnetic circuit was verified by comparing the results with those obtained via the FEM analysis and experiments.
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- 2022
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10. Real Time MODBUS Transmissions and Cryptography Security Designs and Enhancements of Protocol Sensitive Information
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Aamir Shahzad, Malrey Lee, Young-Keun Lee, Suntae Kim, Naixue Xiong, Jae-Young Choi, and Younghwa Cho
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symmetric encryption ,asymmetric encryption ,hashing ,cryptography buffer ,Mathematics ,QA1-939 - Abstract
Information technology (IT) security has become a major concern due to the growing demand for information and massive development of client/server applications for various types of applications running on modern IT infrastructure. How has security been taken into account and which paradigms are necessary to minimize security issues while increasing efficiency, reducing the influence on transmissions, ensuring protocol independency and achieving substantial performance? We have found cryptography to be an absolute security mechanism for client/server architectures, and in this study, a new security design was developed with the MODBUS protocol, which is considered to offer phenomenal performance for future development and enhancement of real IT infrastructure. This study is also considered to be a complete development because security is tested in almost all ways of MODBUS communication. The computed measurements are evaluated to validate the overall development, and the results indicate a substantial improvement in security that is differentiated from conventional methods.
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- 2015
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11. Genetic Variability and Proteome Profiling of a Radiation Induced Cellulase Mutant Mushroom Pleurotus florida
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Chandran Sathesh-Prabu and Young-Keun Lee
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Pleurotus florida ,2D-PAGE ,AFLP ,genetic variability ,mushroom ,Genetics ,QH426-470 ,Microbiology ,QR1-502 - Abstract
We report the genetic similarity changes between a mutant mushroom (Pleurotus florida, designated as PfCM4) having increased cellulolytic activity developed through radiation mutagenesis and its wild type by amplified fragment length polymorphism (AFLP). On average, 23 AFLP fragments were amplified per primer combination, and a total of 286 polymorphic fragments (78.57% polymorphism) with maximal fragment length of 1365 base pairs (bp) were obtained. The genetic similarity between wild type and PfCM4 was found to be 22.30%. In addition, mycelial and secreted protein profiling by 2D-PAGE showed at least three and five different protein spots in the range of 25 kD to 100 kD, respectively, in PfCM4. It seems that the variation in genetic similarity and different expression of both mycelial and secreted proteins in PfCM4 in comparison to the wild type could likely be correlated with its increased cellulolytic activity effected by the irradiation.
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- 2016
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12. The Sensors Connectivity within SCADA Automation Environment and New Trends for Security Development during Multicasting Routing Transmission
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Aamir Shahzad, Kalum Priyanath Udagepola, Young-keun Lee, Soojin Park, and Malrey Lee
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Electronic computers. Computer science ,QA75.5-76.95 - Abstract
This study examined the security of SCADA system and its protocols, more specifically, SCADA/DNP3 protocol security. To achieve the study goals, a SCADA simulation environment is designed for water pumping process through connectivity of intelligent sensors, the payload is constructed, and security is deployed inside DNP3 protocol stack and then bytes are multicast to subcontrollers.
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- 2015
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13. A Secure, Intelligent, and Smart-Sensing Approach for Industrial System Automation and Transmission over Unsecured Wireless Networks
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Aamir Shahzad, Malrey Lee, Neal Naixue Xiong, Gisung Jeong, Young-Keun Lee, Jae-Young Choi, Abdul Wheed Mahesar, and Iftikhar Ahmad
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supervisory control and data acquisition ,industrial automation and control ,remote sensing and monitoring ,wireless sensor network ,remote information analysis and visualization ,human machine interface ,protocols security ,cryptography algorithms ,cellular system ,Chemical technology ,TP1-1185 - Abstract
In Industrial systems, Supervisory control and data acquisition (SCADA) system, the pseudo-transport layer of the distributed network protocol (DNP3) performs the functions of the transport layer and network layer of the open systems interconnection (OSI) model. This study used a simulation design of water pumping system, in-which the network nodes are directly and wirelessly connected with sensors, and are monitored by the main controller, as part of the wireless SCADA system. This study also intends to focus on the security issues inherent in the pseudo-transport layer of the DNP3 protocol. During disassembly and reassembling processes, the pseudo-transport layer keeps track of the bytes sequence. However, no mechanism is available that can verify the message or maintain the integrity of the bytes in the bytes received/transmitted from/to the data link layer or in the send/respond from the main controller/sensors. To properly and sequentially keep track of the bytes, a mechanism is required that can perform verification while bytes are received/transmitted from/to the lower layer of the DNP3 protocol or the send/respond to/from field sensors. For security and byte verification purposes, a mechanism needs to be proposed for the pseudo-transport layer, by employing cryptography algorithm. A dynamic choice security buffer (SB) is designed and employed during the security development. To achieve the desired goals of the proposed study, a pseudo-transport layer stack model is designed using the DNP3 protocol open library and the security is deployed and tested, without changing the original design.
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- 2016
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14. Surgical treatment of tardy ulnar nerve palsy due to non-neurogenic heterotopic ossification in the elbow.
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Se Hwan Lee, Young-Keun Lee, Dong Hee Kim, and Jae Hun An
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- 2024
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15. Acute blockage of forearm supination due to flap tear of the triangular fibrocartilage disc: A case report.
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Ji Woong HO, Jee Yune Kim, and Young-Keun Lee
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- 2024
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16. Multiple flexor tendon ruptures due to osteochondroma of the hamate: A case report
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Tae Young Kwon and Young-Keun Lee
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General Medicine - Published
- 2023
17. Optimization of the Maintenance Track Number for Multifunctional Railway Vehicle Depot
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Chul-Soo Kim, Seung Sub Jung, In Soo Chung, and Young Keun Lee
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- 2022
18. A Study on the protection system to prevent a short circuit of the AC/DC dual voltage electric car
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Young Keun Lee, In Soo Chung, chul Soo Kim, Seung Sub Jung, and Yong min Kang
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- 2022
19. Tibial nerve compression due to osteochondroma of the fibular head: A case report.
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Young-Keun Lee and Ji Woong Ho
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- 2023
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20. Arthroscopic synovectomy of the wrist
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Young-Keun Lee and Jong-Hong Kim
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General Earth and Planetary Sciences ,General Environmental Science - Abstract
The theoretical rationale of synovectomy is to reduce or eliminate the aggressive inflammatory cell mass, thereby reducing swelling, decreasing pain, and improving joint function. Traditionally, open-wrist synovectomy is the standard treatment, as it allows an inspection of all compartments and extensor tendons. Arthroscopic synovectomy of the wrist was first introduced by Roth and Poehling in 1990. Since then, it has been successfully performed in selected patients. Arthroscopic synovectomy might be indicated in any disease that leads to long-standing synovitis of the wrist and when other treatment modalities do not provide satisfactory symptom reduction or may be contraindicated. Arthroscopic synovectomy is a surgical procedure with minimal morbidity. It results in less damage to the joint capsule and ligaments, thereby hastening rehabilitation and shortening the hospital stay. Therefore, we think that understanding the surgical technique for wrist arthroscopic synovectomy and appropriately applying it to patients could prevent disease progression in patients with wrist arthritis and overcome incapacitating dysfunction of the upper limb, including the wrist, hand, and forearm.
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- 2023
21. A 0.65V embedded SDRAM with smart boosting and power management in a 45nm CMOS technology.
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Suk-Soo Pyo, Jun-Sung Kim, Jung-Han Kim, Hyun-Taek Jung, Taejoong Song, Cheol-Ha Lee, Gyun-Hong Kim, Young-Keun Lee, and Kee Sup Kim
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- 2012
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22. Diagnostic Knowledge Acquisition for Agent-Based Medical Applications.
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Thomas M. Gatton, Malrey Lee, Tae-eun Kim, and Young Keun Lee
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- 2007
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23. Algorithm for ABR Traffic Control and Formation Feedback Information.
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Malrey Lee, Dong-Ju Im, Young Keun Lee, Jae-deuk Lee, Suwon Lee, Keun Kwang Lee, and HeeJo Kang
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- 2005
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24. Similarity Retrieval Based on Self-organizing Maps.
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Dong-Ju Im, Malrey Lee, Young Keun Lee, Tae-eun Kim, Suwon Lee, Jaewan Lee, Keun Kwang Lee, and Kyung Dal Cho
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- 2005
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25. GNAQ knockdown promotes bone metastasis through epithelial-mesenchymal transition in lung cancer cells
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Sung Wook Seo, Da Mi Shim, Young Keun Lee, Ji-Yoon Choi, and Yun Sun Lee
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Mirels ,Diseases of the musculoskeletal system ,Biology ,Validity ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Orthopedics and Sports Medicine ,Epithelial–mesenchymal transition ,Lung cancer ,030304 developmental biology ,bone metastasis ,0303 health sciences ,Gene knockdown ,gnaq ,Bone metastasis ,medicine.disease ,Pathological Fracture ,lung cancer ,Oncology ,RC925-935 ,030220 oncology & carcinogenesis ,Cancer cell ,Cancer research ,Surgery ,GNAQ - Abstract
Aims Bone metastasis ultimately occurs due to a complex multistep process, during which the interactions between cancer cells and bone microenvironment play important roles. Prior to colonization of the bone, cancer cells must succeed through a series of steps that will allow them to gain migratory and invasive properties; epithelial-to-mesenchymal transition (EMT) is known to be integral here. The aim of this study was to determine the effects of G protein subunit alpha Q (GNAQ) on the mechanisms underlying bone metastasis through EMT pathway. Methods A total of 80 tissue samples from patients who were surgically treated during January 2012 to December 2014 were used in the present study. Comparative gene analysis revealed that the GNAQ was more frequently altered in metastatic bone lesions than in primary tumour sites in lung cancer patients. We investigated the effects of GNAQ on cell proliferation, migration, EMT, and stem cell transformation using lung cancer cells with GNAQ-knockdown. A xenograft mouse model tested the effect of GNAQ using micro-CT analyses and histological analyses. Results GNAQ-knockdown showed down-regulation of tumour growth through mitogen-activated protein kinase (MAPK) signalling in lung cancer cells, but not increased apoptosis. We found that GNAQ-knockdown induced EMT and promoted invasiveness. GNAQ-knockdown cells injected into the bone marrow of murine tibia induced tumour growth and bone-to-lung metastasis, whereas it did not in control mice. Moreover, the knockdown of GNAQ enhanced cancer stem cell-like properties in lung cancer cells, which resulted in the development of resistance to chemotherapy. Conclusion The present study reveals that the GNAQ-knockdown induced cancer stem cell-like properties. Cite this article: Bone Joint Res 2021;10(5):310–320.
- Published
- 2021
26. Comparison of the clinical and radiological outcomes between an isolated tibial component revision and total revision knee arthroplasty in aseptic loosening of an isolated tibial component
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Young Keun Lee, Jun-Seok Park, Sung-Sahn Lee, and Young-Wan Moon
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Reoperation ,musculoskeletal diseases ,medicine.medical_specialty ,WOMAC ,Knee Joint ,medicine.medical_treatment ,Aseptic loosening ,Osteoarthritis ,03 medical and health sciences ,0302 clinical medicine ,Blood loss ,Humans ,Medicine ,Orthopedics and Sports Medicine ,Femoral component ,Arthroplasty, Replacement, Knee ,Retrospective Studies ,030222 orthopedics ,Tibia ,business.industry ,Osteoarthritis, Knee ,musculoskeletal system ,medicine.disease ,Arthroplasty ,Prosthesis Failure ,Surgery ,Treatment Outcome ,Radiological weapon ,Knee Prosthesis ,business ,Range of motion ,030217 neurology & neurosurgery - Abstract
An isolated tibial component revision could be a treatment option for isolated tibial side loosening; however, few studies have proved its efficacy. This study aimed to compare the clinical and radiological outcomes between isolated (tibial component) and total (femoral and tibial component) revision total knee arthroplasty (TKA).Between January 2008 and February 2017, 31 patients underwent revision TKA for isolated tibial side loosening; 14 underwent an isolated tibial component revision (isolated group) and 17 underwent total (both femoral and tibial components) revision surgery (total group). The postoperative range of motion (ROM), Western Ontario and McMaster Universities osteoarthritis (WOMAC) index, Knee Society knee score (KSKS), Knee Society function score (KSFS), and mechanical axis (MA) were compared between the two groups. The intraoperative tourniquet time and amount of blood drainage were also compared.The mean follow-up durations in the isolated and total groups were 40.7 and 56.1 months, respectively. Both groups had similar postoperative ROM, WOMAC index, KSKS, KSFS, and MA; however, significantly shorter tourniquet time (105.2 vs. 154.6 min, P 0.001) and less blood drainage (417.2 vs. 968.1 ml, P 0.001) were noted in the isolated group than in the total group.Isolated tibial component revision TKA for tibial component loosening showed comparable clinical and radiological outcomes to those of total revision TKA. The advantages of the isolated tibial component revision surgery were short operation time and small blood loss.Level III, Retrospective comparative study.
- Published
- 2021
27. Discovery of genes positively modulating treatment effect using potential outcome framework and Bayesian update
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Young Keun, Lee, Jisoo, Kim, and Sung Wook, Seo
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Causality ,ComputingMethodologies_PATTERNRECOGNITION ,Data Collection ,Health Policy ,Humans ,Bayes Theorem ,Health Informatics ,Genomics ,Algorithms ,Computer Science Applications - Abstract
Background The recent explosion of cancer genomics provides extensive information about mutations and gene expression changes in cancer. However, most of the identified gene mutations are not clinically utilized. It remains uncertain whether the presence of a certain genetic alteration will affect treatment response. Conventional statistics have limitations for causal inferences and are hard to gain sufficient power in genomic datasets. Here, we developed and evaluated a C-search algorithm for searching the causal genes that maximize the effect of the treatment. Methods The algorithm was developed based on the potential outcome framework and Bayesian posterior update. The precision of the algorithm was validated using a simulation dataset. The algorithm was implemented to a cBioPortal dataset. The genes discovered by the algorithm were externally validated within CancerSCAN screening data from Samsung Medical Center. Results Simulation data analysis showed that the C-search algorithm was able to identify nine causal genes out of ten. The C-search algorithm shows the discovery rate rapidly increasing until the 1500 data instances. Meanwhile, the log-rank test shows a slower increase in performance. The C-search algorithm was able to suggest nine causal genes from the cBioPortal Metabric dataset. Treating the patients with the causal genes is associated with better survival outcome in both the cBioPortal dataset and the CancerSCAN dataset which is used for external validation. Conclusions Our C-search algorithm demonstrated better performance to identify causal effects of the genes than multiple log-rank test analysis especially within a limited number of data. The result suggests that the C-search can discover the causal genes from various genetic datasets, where the number of samples is limited compared to the number of variables.
- Published
- 2022
28. Preoperative Medial Tightness and Narrow Medial Joint Space Are Predictive Factors for Lower Extremity Alignment Change Toward Varus After Opening-Wedge High Tibial Osteotomy
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Sung-Sahn Lee, Young Keun Lee, Il Su Kim, Dong Jin Ryu, Eui Yub Jung, Do Kyung Lee, and Joon Ho Wang
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Orthopedics and Sports Medicine - Abstract
Background:Time-dependent changes in lower extremity alignment after an opening-wedge high tibial osteotomy (OWHTO) have been poorly investigated. Moreover, few studies have investigated risk factors of postoperative alignment change.Purposes:To investigate time-dependent alignment changes and identify predictive factors for postoperative alignment change after OWHTO.Study Design:Case-control study; Level of evidence, 3.Methods:This study included patients who underwent OWHTO between March 2010 and September 2018. A total of 142 knees with a mean follow-up of 42 months were included and classified as the change group when the amount of hip-knee-ankle (HKA) angle change was >1°; if otherwise, then as the no-change group. HKA angle was obtained at 6 time points: preoperatively and at 3 months, 6 months, 1 year, 2 years, and final follow-up postoperatively. Multiple regression analysis was performed to identify the factors that were correlated with the changes in the HKA angle from 3 months to the final follow-up.Results:Among the 142 knees, 59 (42%) were included in the change group. The overall postoperative HKA angles progressed serially toward varus after OWHTO. The mean angles of the 6 time points were 8.5°, –3.7°, –3.6°, –3.3°, –3.1°, and –2.7°, respectively. The mean HKA angles of the change and no-change groups were 9.1°, –4.3°, –3.4°, –2.8°, –2.0°, and –1.4° and 8.1°, –3.3°, –3.8°, –3.6°, –3.8°, and –3.7°, respectively. Greater change in the HKA angle was predicted by preoperatively greater valgus stress joint line convergence angles and less medial joint space width.Conclusion:Of the cases of OWHTO, 42% showed correction loss of >1° at a mean follow-up of 42 months. The overall postoperative HKA angles progressed serially to varus angles after OWHTO. Preoperative greater valgus stress joint line convergence angles and less medial joint space width were predictive factors for greater change in alignment toward varus after OWHTO.
- Published
- 2022
29. Partial Stack Cooling Storage Effects of Spring Kimchi Cabbage
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Sung-Gi Min, Eung Soo Han, Sang Hyun Ha, Jong-Seok Hwang, Jun Young Jeon, and Young-Keun Lee
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Materials science ,Stack (abstract data type) ,Spring (mathematics) ,Composite material ,Food Science - Published
- 2020
30. Arthroscopic Bone Grafting and Kirschner-Wires Fixation for Scaphoid Nonunion
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Young Keun Lee, Ha Song Lee, and Mooheon Jeon
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musculoskeletal diseases ,030222 orthopedics ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,medicine.medical_treatment ,Arthroscopy ,Scaphoid nonunion ,030229 sport sciences ,Bone grafting ,musculoskeletal system ,Surgery ,body regions ,03 medical and health sciences ,Fixation (surgical) ,surgical procedures, operative ,0302 clinical medicine ,Bone transplantation ,Scaphoid bone ,medicine ,General Earth and Planetary Sciences ,business ,General Environmental Science - Abstract
Various surgical techniques, such as corticocancellous or cancellous bone graft and other vascularized bone grafting techniques have been developed to treat scaphoid nonunion. However, open grafting with dissection of wrist capsule and ligaments damages the joint and hence can lead to increased stiffness of the wrist and hand. Arthroscopic assisted bone grafting and percutaneous fixation have advantages such as minimal surgical trauma to the scaphoid blood supply and its ligament connection and provide a thorough wrist assessment, comprehensive approach for scaphoid nonunion and its sequelae in a minimally invasive manner. This article briefly discusses the characteristic anatomy of the wrist and scaphoid, and reviews the technique of arthroscopic bone grafting and percutaneous fixation for the treatment of scaphoid nonunion.
- Published
- 2020
31. Results of Arthroscopically Assisted Volar and Dorsal Scapholunate Ligament Reconstruction Using Flexor Carpi Radialis: Modified Arthroscopic Corella Technique
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Yong-Cheol Park, Myung-Sun Kim, Young-Keun Lee, Chang-Young Seo, and Sang-Gyoo Shin
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Dorsum ,030222 orthopedics ,03 medical and health sciences ,0302 clinical medicine ,business.industry ,General Earth and Planetary Sciences ,Medicine ,Anatomy ,030230 surgery ,Scapholunate ligament ,business ,General Environmental Science - Abstract
Purpose: We evaluated results of arthroscopically assisted volar and dorsal scapholunate(SL) ligament reconstruction using flexor carpi radialis(FCR). Methods: We reviewed 31 cases who had been operated from August 2015 to June 2018. Two cases were excluded and 4 cases lost contact. Twenty five wrists were included. The average follow-up duration was 25.3months. Diagnostic arthroscopy was performed to evaluate EWAS stage of SL instability and the reparability of SL ligament. The SL reconstruction was performed for the cases which showed EWAS stage IIIC, IV having gap over 3mm and irreparable SL ligament. The interval between the diagnosis and operation was 5.9 days in average. We modified the arthroscopic Corella technique by repairing the graft tendon to FCR. Results: All SL joints were stabilized to EWAS stage I arthroscopically after reconstruction. DASH score changed from 32.7 to 9.7. Grip power changed from 74.1% to 93.3%. Modified Mayo Wrist score was 83.8. Preoperative SL angle was 53.8。, postoperative 49.6。 and the last was 51.2。. The improvement between preoperative and last follow-up SL angle was statistically significant(p
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- 2020
32. Acute compartment syndrome of the forearm associated with transradial coronary intervention
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Se-Hwan Lee, Tae-Young Kwon, and Young-Keun Lee
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medicine.medical_specialty ,Percutaneous ,medicine.medical_treatment ,030204 cardiovascular system & hematology ,Compartment Syndromes ,03 medical and health sciences ,Percutaneous Coronary Intervention ,0302 clinical medicine ,Forearm ,Internal medicine ,Intervention (counseling) ,medicine.artery ,medicine ,Humans ,Radial artery ,Compartment (pharmacokinetics) ,Aged ,Retrospective Studies ,business.industry ,Percutaneous coronary intervention ,body regions ,medicine.anatomical_structure ,Forearm compartment syndrome ,Radial Artery ,Cardiology ,Surgery ,business ,030217 neurology & neurosurgery ,Artery - Abstract
This study documents our experience with acute forearm compartment syndrome after percutaneous transradial coronary artery intervention and suggests several strategies to achieve good results. A retrospective review identified the medical records of four patients with acute forearm compartment syndrome after transradial intervention who were treated by urgent fasciotomy. The mean time from the onset of symptoms to operation was 5.7 hours. In three cases bleeding was from radial artery rupture at the puncture site, and one case was caused by brachial artery rupture at the level of the distal humerus and radial artery rupture at the level of proximal forearm. We obtained satisfactory results without any complications. If acute forearm compartment syndrome after transradial intervention is diagnosed, the site of bleeding should be identified preoperatively. Early surgical decompression produced satisfactory results even in elderly patients. Level of evidence: IV
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- 2020
33. 13.2 A 14nm FinFET 128Mb 6T SRAM with VMIN-enhancement techniques for low-power applications.
- Author
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Taejoong Song, Woojin Rim, Jonghoon Jung, Giyong Yang, Jaeho Park, Sunghyun Park 0003, Kang-Hyun Baek, Sanghoon Baek, Sang-Kyu Oh, Jinsuk Jung, Sungbong Kim, Gyu-Hong Kim, Jintae Kim, Young-Keun Lee, Kee Sup Kim, Sang-Pil Sim, Jong Shik Yoon, and Kyu-Myung Choi
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- 2014
- Full Text
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34. The fate of delayed revascularization for neglected vascular injury of incompletely amputated digits and hands
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Young Woo Kim, Seong Woo Chong, Young Keun Lee, Sang Hyun Woo, and Ho Jun Cheon
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Adult ,Male ,Reoperation ,medicine.medical_specialty ,Necrosis ,Adolescent ,medicine.medical_treatment ,Vein graft ,030230 surgery ,Anastomosis ,Revascularization ,Fingers ,03 medical and health sciences ,0302 clinical medicine ,Amputation, Traumatic ,Finger Injuries ,medicine ,Humans ,Warm Ischemia ,Child ,Skin repair ,030222 orthopedics ,business.industry ,Anastomosis, Surgical ,Hand Injuries ,Middle Aged ,Plastic Surgery Procedures ,Vascular System Injuries ,Hand ,Surgery ,Tendon ,medicine.anatomical_structure ,Primary bone ,Amputation ,Child, Preschool ,Female ,medicine.symptom ,business - Abstract
We report the fate of neglected vascular injury in cases of incomplete amputation of the digits and hand after delayed revascularization. Twelve patients underwent primary bone fixation, tendon or skin repair for hand injuries without vessel repair despite ischaemic findings. There was discoloration or necrosis of the fingertips during follow-up examination and the patients were referred to us for treatment. The mean warm ischaemic time was 53 hours (range 17–120). Delayed revascularization was performed with end-to-end anastomosis of the digital arteries in eight and vein graft in four cases. Digital nerves were repaired in four cases and flexor tendons in two cases. Of the 12 cases, eight cases showed complete survival. However, in four patients, complete necrosis of the fingers occurred, with one finger surviving partially. Revision amputation was performed in the four cases where necrosis occurred. We conclude that neglected vascular injury associated with incomplete amputation of digits and hands can be overcome in some patients by delayed revascularization even after prolonged warm ischaemic time. Level of evidence: IV
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- 2019
35. The usefulness of ultrasound and the posterior fat pad sign in pulled elbow
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Woo Young Jang, Seul Gi Kim, Young Keun Lee, Seok Ha Hong, Donghee Kwak, and Soon Hyuck Lee
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Male ,musculoskeletal diseases ,medicine.medical_specialty ,Radiography ,Elbow ,Joint Dislocations ,Elbow pain ,03 medical and health sciences ,0302 clinical medicine ,Elbow Joint ,medicine ,Humans ,Child ,Retrospective Studies ,Ultrasonography ,General Environmental Science ,030222 orthopedics ,Ligaments ,business.industry ,Ultrasound ,Infant ,030208 emergency & critical care medicine ,musculoskeletal system ,Surgery ,body regions ,medicine.anatomical_structure ,Adipose Tissue ,Child, Preschool ,Fat pad sign ,Ligament ,General Earth and Planetary Sciences ,Female ,Plain radiographs ,medicine.symptom ,Elbow Injuries ,business - Abstract
Introduction A pulled elbow is a common cause of acute elbow pain that is generally managed by a reduction maneuver without radiographic examination. However, children with atypical presentation with no history of abrupt longitudinal traction should undergo elbow imaging. This study aimed to investigate plain radiography findings and determine the usefulness of ultrasonography (US) in atypical pulled elbow. Materials and methods We retrospectively reviewed the medical records and images of 37 (22 males) consecutive patients with pulled elbow who presented with an atypical history or failed reduction between April 2015 and September 2018. Mean age at presentation was 4.34 years (range, 1.25–9.5 years). Of the 37 elbows, 20 were left elbows. The injury mechanism, incidence of the posterior fat pad sign on plain radiographs, and characteristic US findings, pre- and post- reduction, were investigated. Results The original mechanisms of injury included slipping (n = 14), rolling over the arm (n = 7), vague history (n = 6), falling down (n = 6), abrupt longitudinal traction (n = 2), and direct injury (n = 2). On plain radiographs, six of the 37 elbows (16%) showed the posterior fat pad sign. Before the reduction, an entrapped supinator, a pathognomonic sign of pulled elbow, was identified on US in all cases. After reduction, the characteristic US findings showed a disentangled and swollen supinator (100%) and restored annular ligament (100%) in all successful cases. Although a click was not felt in three cases, the reductions were considered successful because the annular ligament was restored on US with free elbow motion. Conclusion Pulled elbow may be caused by atypical mechanisms of injury, such as slipping and rolling over the arm. Clinicians should be aware of the possibility of the posterior fat pad sign on plain radiographs of pulled elbow to prevent unnecessary immobilization. In such circumstances, US is a useful method for detecting an entrapped supinator and confirming adequate reduction via restoration of the annular ligament in children with atypical pulled elbow.
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- 2019
36. Arthroscopy-assisted bone grafting for the treatment of SNAC stage I without radial styloidectomy
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Young-Keun, Lee and Young-Ran, Jung
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Scaphoid Bone ,Wrist Joint ,Arthroscopy ,Bone Transplantation ,Treatment Outcome ,Humans ,General Medicine ,Range of Motion, Articular ,Retrospective Studies - Abstract
To report the clinical and radiological outcomes of arthroscopic bone grafting and percutaneous K-wire fixation without radial styloidectomy in patients with scaphoid nonunion advanced collapse (SNAC). We retrospectively analyzed the records of 15 patients with SNAC who were treated with arthroscopic bone grafting and percutaneous K-wire fixation and subsequently followed up for a minimum of 1 year between November 2009 and March 2018. The clinical outcomes were evaluated by comparing the range of motion (ROM), grip strength, the modified Mayo Wrist Score, and visual analog scale (VAS) scores for pain, all of which were measured preoperatively and at the last follow-up. The radiologic outcomes were evaluated by comparing the scapholunate (SL) and radiolunate (RL) angles preoperatively and at the last follow-up. All 15 cases of nonunion were resolved. The average radiologic union time was 9.7 ± 1.2 weeks. The average VAS score increased from 5.7 ± 2.3 (range, 2 - 10) preoperatively to 1.3 ± 1.3 (range, 0 - 3) at the last follow-up (P.05). The average modified Mayo wrist score increased from 58.3 ± 14.0 preoperatively to 80.0 ± 9.2 at the last follow-up (P.05). The mean ROM of the wrist improved, but there was no statistical significance. At the last follow-up, the mean flexion and radial deviation on the affected side were significantly decreased, and the mean extension on the affected side was significantly improved compared to the normal side (P.05). The mean preoperative SL and RL angles were 66 ± 11.9° and 7.2 ± 6.8°, respectively, and were decreased to 50.4 ± 7.5° and 6.4 ± 5.2°, respectively, at the last follow-up. The mean SL angle was significantly corrected (P = .01). Arthroscopic bone grafting and percutaneous Kerschner (K)-wire fixation without radial styloidectomy are considered to be very effective methods for correcting scaphoid deformities to treat SNAC stage I. However, caution may be needed during the surgery to prevent reductions in flexion and the radial deviation of the wrist.
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- 2022
37. Formation of multiple ganglion cysts along the flexor tendon after open A1 pulley release for trigger finger: A case report
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Young Keun, Lee
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Ganglion Cysts ,Tendons ,Trigger Finger Disorder ,Tendon Injuries ,Finger Injuries ,Humans ,General Medicine ,Aged - Abstract
When surgical treatment is indicated for primary trigger finger, open A1 pulley release has traditionally been recommended with generally good results. However, ganglion cysts of the flexor tendon sheath as a complication after an open A1 pulley release were rarely reported. Therefore, the purpose of this study is to report a case of multiple ganglion cysts arising from the flexor tendon sheath in a patient undergoing an open A1 pulley release for trigger finger disorder with a review of the relevant literature.A 65-year-old right-handed farmer was referred to our hospital for swelling in the left long finger (LLF). One year before the visit, the patient was diagnosed with trigger finger in the LLF at other hospital and an open A1 pulley release was performed, but the swelling of the finger persisted. The patient had no history of trauma or evidence of systemic disease such as rheumatoid or other inflammatory arthritis. The patient was diagnosed with multiple ganglion cysts of flexor tendon sheath after investigation.We successfully excised cystic masses and debrided the partially ruptured flexor digitorum superficialis (FDS) tendon and sutured it using 5/0 prolene. At 12-month follow-up, the patient was completely asymptomatic with excellent range of motion in the distal interphalangeal (DIP) joint (0°-60°) of his LLF, showing no recurrence of ganglion cyst.Trigger finger is a common condition that clinicians encounter frequently. However, this familiarity may lead to inattentive treatment. Nevertheless, through this case, clinicians should devote careful attention when performing open A1 pulley release to prevent partial rupture of the flexor tendon in the A1 pulley. If ganglion cysts occur, we believe that surgical excision can yield good results.
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- 2022
38. Arthroscopic treatment of chronic wrist pain after distal radius fractures
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Tae-Young Kwon, Ha-Song Lee, and Young-Keun Lee
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Adult ,Male ,medicine.medical_specialty ,Visual analogue scale ,distal radius fracture ,Observational Study ,Wrist pain ,03 medical and health sciences ,Grip strength ,Arthroscopy ,Young Adult ,0302 clinical medicine ,wrist arthroscopy ,medicine ,Humans ,030212 general & internal medicine ,Aged ,Retrospective Studies ,Ulnar impaction syndrome ,medicine.diagnostic_test ,business.industry ,General Medicine ,Middle Aged ,Wrist Injuries ,Surgery ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Ligament ,Female ,medicine.symptom ,Range of motion ,business ,Radius Fractures ,chronic pain ,Triangular Fibrocartilage Complex ,Research Article - Abstract
We report the arthroscopic and clinical findings of patients with chronic wrist pain following distal radius fracture (DRF) who underwent diagnostic arthroscopy and arthroscopically-assisted tailored treatment. We retrospectively analyzed the records of 15 patients with chronic wrist pain following DRF, who underwent diagnostic arthroscopy and arthroscopically-assisted tailored treatment from 2010 to 2017. The average patient age was 44 years (range, 20–68 years), average time from injury to treatment 21 ± 23.46 months (range, 3–96 months) and average follow up period 20.13 ± 8.71 months (range, 12–39 months). The functional outcome was evaluated by comparing the preoperative and final follow up values of the range of motion, grip strength, pinch strength, visual analogue scale for pain and quick disabilities of the arm, shoulder and hand score. Based on the arthroscopic findings, synovitis was found in all cases and the pathologic intra-articular lesions were classified into 4 patterns. Triangular fibrocartilage complex rupture was seen in 14 cases, intercarpal and radiocarpal ligament ruptures in 9 cases, ulnar impaction syndrome in 5 cases, and cartilage lesion in 9 cases. In terms of surgical treatment, 15 patients underwent arthroscopic synovectomy, 7 foveal or capsular repair of TFCC, 7 intercarpal Kirschner wires fixation or intercarpal thermal shrinkage, 1 intercarpal ligament reconstruction, 2 Sauve-Kapandji procedure, and 2 unlar shortening osteotomy. Postoperatively, the average range of motion, grip strength, and pinch strength increased significantly. From preoperative to final follow up values, the average visual analogue scale and quick disabilities of the arm score decreased from 5.93 ± 1.58 (range, 3–8) to 1.33 ± 1.29 (range, 0–3) (P = .001) and from 49.38 ± 19.09 to 12.63 ± 7.63 (P = .001), respectively. Diagnostic arthroscopy and arthroscopically-assisted tailored treatment of chronic wrist pain following DRF can provide an accurate diagnosis, significant pain relief, and functional improvement.
- Published
- 2020
39. Trigger finger secondary to a neglected flexor tendon rupture
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Young-Ran Jung, Young-Keun Lee, and Malrey Lee
- Subjects
Adult ,Male ,medicine.medical_specialty ,Visual Analog Scale ,Visual analogue scale ,Observational Study ,Ruptured tendon ,Lacerations ,Trigger finger ,Tendons ,03 medical and health sciences ,0302 clinical medicine ,Tendon Injuries ,Patient age ,Finger Injuries ,Secondary Prevention ,medicine ,Humans ,030212 general & internal medicine ,Range of Motion, Articular ,Flexor tendon ,Retrospective Studies ,Vas score ,Neglected ,Rupture ,business.industry ,Neglected Diseases ,General Medicine ,Middle Aged ,610 Medical sciences ,Medicine ,musculoskeletal system ,medicine.disease ,Surgery ,Tendon ,body regions ,medicine.anatomical_structure ,ddc: 610 ,Trigger Finger Disorder ,030220 oncology & carcinogenesis ,Laceration ,Female ,business ,Range of motion ,Research Article - Abstract
Objectives/Interrogation: The purpose of this study is to present secondary trigger finger caused by a neglected partial flexor tendon rupture including discussion of the mechanism and treatment. Methods: We retrospectively reviewed the records of six patients with trigger finger caused by[for full text, please go to the a.m. URL], 14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT)
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- 2020
- Full Text
- View/download PDF
40. Polarization Effect of Hot Electrons in Tandem-Structured Plasmonic Nanodiode
- Author
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Yujin Park, Changhwan Lee, Young Keun Lee, and Jeong Young Park
- Subjects
Materials science ,Schottky barrier ,Physics::Optics ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Condensed Matter::Materials Science ,Electrical and Electronic Engineering ,Plasmon ,Photocurrent ,biology ,business.industry ,Surface plasmon ,Schottky diode ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Ray ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Semiconductor ,Optoelectronics ,Nanodiodes ,0210 nano-technology ,business ,Biotechnology - Abstract
Energy conversion from light to electricity mediated by hot electrons in a plasmonic metal nanostructure caused by the decay of surface plasmons has been proposed as a promising way to obtain novel photovoltaics and photocatalytic devices. In Schottky barriers composed of metal nanostructures supported on a semiconductor surface, hot electrons produced in the metal with sufficient photon energy can be extracted into the conduction band of the semiconductor by overcoming the Schottky barrier. An important parameter for the efficient extraction of hot electrons is the polarization of the incident light, which can be tuned by the angle between the electric field of the incident light and the plane of the Schottky barrier. Here, we investigate polarization-dependent hot electrons detected on planar (two-dimensional) and three-dimensional (3D) tandem plasmonic Au/TiO2 nanodiodes. We confirm that the maximum photocurrent was obtained with the planar structure in transverse mode and with the 3D tandem structure ...
- Published
- 2018
41. Three-dimensional hot electron photovoltaic device with vertically aligned TiO2 nanotubes
- Author
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Kalyan C. Goddeti, Changhwan Lee, Jeong Young Park, and Young Keun Lee
- Subjects
Materials science ,Photon ,Science ,Physics::Optics ,02 engineering and technology ,Photon energy ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,Condensed Matter::Materials Science ,Electric field ,Physics::Atomic and Molecular Clusters ,Absorption (electromagnetic radiation) ,Plasmon ,Multidisciplinary ,business.industry ,Surface plasmon ,Photovoltaic system ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Titanium dioxide ,Optoelectronics ,Medicine ,0210 nano-technology ,business - Abstract
Titanium dioxide (TiO2) nanotubes with vertically aligned array structures show substantial advantages in solar cells as an electron transport material that offers a large surface area where charges travel linearly along the nanotubes. Integrating this one-dimensional semiconductor material with plasmonic metals to create a three-dimensional plasmonic nanodiode can influence solar energy conversion by utilizing the generated hot electrons. Here, we devised plasmonic Au/TiO2 and Ag/TiO2 nanodiode architectures composed of TiO2 nanotube arrays for enhanced photon absorption, and for the subsequent generation and capture of hot carriers. The photocurrents and incident photon to current conversion efficiencies (IPCE) were obtained as a function of photon energy for hot electron detection. We observed enhanced photocurrents and IPCE using the Ag/TiO2 nanodiode. The strong plasmonic peaks of the Au and Ag from the IPCE clearly indicate an enhancement of the hot electron flux resulting from the presence of surface plasmons. The calculated electric fields and the corresponding absorbances of the nanodiode using finite-difference time-domain simulation methods are also in good agreement with the experimental results. These results show a unique strategy of combining a hot electron photovoltaic device with a three-dimensional architecture, which has the clear advantages of maximizing light absorption and a metal–semiconductor interface area.
- Published
- 2018
42. Enhancement of Hot Electron Flow in Plasmonic Nanodiodes by Incorporating PbS Quantum Dots
- Author
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Sohee Jeong, Jeong Young Park, Young Keun Lee, Hyekyoung Choi, Changhwan Lee, and Ievgen I. Nedrygailov
- Subjects
Materials science ,Band gap ,Schottky barrier ,Physics::Optics ,02 engineering and technology ,Photodetection ,010402 general chemistry ,01 natural sciences ,Condensed Matter::Materials Science ,symbols.namesake ,General Materials Science ,Plasmon ,Photocurrent ,biology ,business.industry ,Fermi level ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,biology.organism_classification ,0104 chemical sciences ,Quantum dot ,symbols ,Optoelectronics ,Nanodiodes ,0210 nano-technology ,business - Abstract
The enhancement of hot electron generation using plasmonic nanostructures is a promising strategy for developing photovoltaic devices. Here, we show that hot electron flow generated in plasmonic Au/TiO2 nanodiodes by incident light can be amplified when PbS quantum dots are deposited onto the surface of the nanodiodes. The effect is attributed to efficient extraction of hot electrons via a three-dimensional Schottky barrier, thus giving new pathways for hot electron transfer. We also demonstrate a correlation between the photocurrent and Schottky barrier height when using PbS quantum dots with varying size and ligand treatments that allow us to control the electric properties (e.g., band gap and Fermi level, respectively) of the PbS quantum dots. This simple method introduces a new technique for further improving the power conversion efficiency of thin-film photovoltaic devices.
- Published
- 2018
43. Does Low-Dose Heparin Have a Significant Role in Free Flap Surgery?
- Author
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M. Diya Sabbagh, Si-Gyun Roh, Young-Keun Lee, Mun-Young An, Jin Yong Shin, and Nae-Ho Lee
- Subjects
medicine.medical_specialty ,Necrosis ,030230 surgery ,Dehiscence ,03 medical and health sciences ,0302 clinical medicine ,Hematoma ,Medicine ,Heparin ,business.industry ,medicine.disease ,Thrombosis ,Surgery ,Otorhinolaryngology ,Free tissue flaps ,030220 oncology & carcinogenesis ,Anesthesia ,Original Article ,medicine.symptom ,business ,Free flap surgery ,Heparin group ,Low dose heparin ,medicine.drug - Abstract
Background It is controversial issue that heparin decreases thrombosis for microsurgical anastomosis, and its effective role is under discussion. This study is for proving whether low-dose heparin is preventing thrombosis in free flap reconstruction. Methods Through chart reviews of 134 patients, using low-dose heparin for free tissue transfer from 2011 to 2016, retrospective analysis was performed. 33 patients received low-dose heparin therapy after surgery. And 101 patients received no-heparin therapy. Complications included flap necrosis, hematoma formation, dehiscence and infection. Results In no-heparin therapy group, comparing the flap necrosis revealed 16 cases (15.84%). And, flap necrosis was 6 cases (18.18%) in low-dose heparin therapy group. The statistical analysis of flap necrosis rate showed no significant difference (p=0.75). The results showed that there was no significant difference of flap necrosis rate between two groups. Conclusion In this study, patients in the low-dose heparin group had no significantly lower rates of flap failure compared with no-heparin group. This suggests that low-dose heparin may not prevent thrombosis and subsequent flap failure to a significant extent.
- Published
- 2017
44. Hand and Wrist Injuries in Golfers and Their Treatment
- Author
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Jong Min Kim, Young-Keun Lee, William H J Chung, Ho-Jun Cheon, and Sang Hyun Woo
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,Wrist ,Wrist injury ,Fractures, Bone ,03 medical and health sciences ,0302 clinical medicine ,Tendon Injuries ,medicine ,Humans ,Orthopedics and Sports Medicine ,De Quervain Disease ,Rupture ,030222 orthopedics ,Braces ,business.industry ,Anti-Inflammatory Agents, Non-Steroidal ,Hand Injuries ,030229 sport sciences ,Wrist Injuries ,musculoskeletal system ,medicine.disease ,Brace ,Surgery ,body regions ,medicine.anatomical_structure ,Splints ,Physical therapy ,Hamate fracture ,Golf ,Trigger finger ,Tendinopathy ,Splint (medicine) ,business ,human activities - Abstract
A thorough understanding of the swing phases and mechanisms of injury in golf allows accurate diagnosis, treatment, and future prevention of injuries. Recommended initial treatment starts with cessation of practice to rest the wrist, a splint or orthotic brace, and nonsteroidal antiinflammatory drug medication with corticosteroid injection and swing modification. Pisiform excision is the best treatment of the most severe chronic cases of pisiform ligament complex syndrome. Delayed diagnosis of hook of hamate fracture may lead to complications, including flexor tendon rupture. Prompt surgical resection is recommended to hasten return to sport and to prevent further complications.
- Published
- 2017
45. The Intelligent Healthcare Data Management System Using Nanosensors
- Author
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Young Keun Lee, Jae-Young Choi, Malrey Lee, Gisung Jeong, and Ulzii-Orshikh Dorj
- Subjects
Waiting time ,020203 distributed computing ,030506 rehabilitation ,Article Subject ,Computer science ,business.industry ,02 engineering and technology ,03 medical and health sciences ,Control and Systems Engineering ,Nanosensor ,lcsh:Technology (General) ,Management system ,0202 electrical engineering, electronic engineering, information engineering ,lcsh:T1-995 ,Electrical and Electronic Engineering ,0305 other medical science ,Healthcare data ,business ,Instrumentation ,Mobile device ,Communication channel ,Computer network - Abstract
We developed a design of Intelligent Healthcare Data Management System using nanosensors (IHDMS) and composed an application for mobile device. The proposed IHDMS will coordinate the healthcare data of the patients from nanosensors and transforms it into a worldwide consumed standard HL7 (Health Level Seven) for conversion of healthcare data. This converted data dispatches to a server of its system. The battery lifetime of the facility is feasible to increase, the memory usage is less than 100 KB, and it operates all data by employing few and far between resources. Moreover, the proposed system decreases the waiting time in the transposing data, and secured channel was used for the server of the healthcare center in the running HL7 format data.
- Published
- 2017
46. The clinical result of arterialized venous free flaps for the treatment of soft tissue defect of the fingers
- Author
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Young-Keun Lee, Dong-Hee Kim, and Malrey Lee
- Subjects
Adult ,Male ,medicine.medical_specialty ,Soft Tissue Injuries ,Treatment outcome ,Observational Study ,Free flap ,Free Tissue Flaps ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Vascularity ,finger ,Forearm ,soft tissue injury ,Finger Injuries ,medicine ,Humans ,030212 general & internal medicine ,Retrospective Studies ,Distal forearm ,business.industry ,Soft tissue ,arterialized venous free flap ,General Medicine ,Skin Transplantation ,Phalanx ,Middle Aged ,Plastic Surgery Procedures ,Bone cement ,eye diseases ,Surgery ,medicine.anatomical_structure ,Treatment Outcome ,030220 oncology & carcinogenesis ,Female ,medicine.symptom ,business ,Research Article - Abstract
The purpose of this study is to report the clinical results of the arterialized venous free flaps in reconstructing soft tissue defects of the finger and to extend the indications for the use of the flaps based on clinical experiences of the authors. We retrospectively reviewed the records of 35 patients who underwent an arterialized venous free flaps for a finger reconstruction, between May 2007 and August 2015. The mean size of flap was 4.8 ± 1.23 × 3.1 ± 0.84 cm. The donor site was the ipsilateral volar aspect of the distal forearm in all cases. There were 17 (48.6%) cases of venous skin flaps, 9 (25.7%) cases of innervated venous flaps, 7 (20%) cases of tendocu taneous flaps, and 2 (5.7%) case of innervated tendocutaneous flap. The vascularity of recipient beds was good except 8 (22.9%) cases (partial devascularity in 3, more than 50% avascularity [bone cement] in 3, and chronic infected bed in 2). Of the 35 cases, 29 (82.9%) cases (including 3 cases who had more than 50% avascularity recipient bed) showed complete survival. 3 (8.6%) cases, which had partially devascularity of distal phalanx in recipient bed, showed partial necrosis (P = .015). The mean number of included veins was 2.4 ± 0.5 for a flap. A forearm arterialized venous free flap is a useful procedure for single-stage reconstructing of a soft tissue or combined defect of a finger, we consider that this technique could be applied to fingers despite an avascular or insufficient vascular recipient bed if the periphery of recipient bed vascularity was good and if the recipient beds were free from infection.
- Published
- 2019
47. Anatomy and Biomechanics
- Author
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Young Keun Lee
- Subjects
musculoskeletal diseases ,body regions ,Circumduction ,medicine.medical_specialty ,medicine.anatomical_structure ,Physical medicine and rehabilitation ,Computer science ,medicine ,Biomechanics ,Pillar ,Effective treatment ,Thumb ,Hand surgeons - Abstract
The thumb is smaller and thicker than the other fingers but has always been represented as the pillar of the hand. The human thumb has evolved in the direction of increasing mobility and strength, although the stability is relatively lost in the evolutionary process. Thus, by performing the unique function of the thumb such as prehension, opposition, and circumduction, the hand enables not only fine and delicate tasks but also gross and powerful movements. This unique function of the thumb is partly due to the special arrangement of its bony column and associated muscles. Therefore, an accurate and comprehensive understanding of the anatomical features and biomechanics of the thumb provides a more accurate understanding of the diseases and traumas that occur on the thumb and will help hand surgeons to do more effective treatment.
- Published
- 2019
48. Arthroscopic-assisted bone grafting and percutaneous K-wires fixation for the treatment of scaphoid nonunion in the skeletally immature patient
- Author
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Ki Bum Kim and Young-Keun Lee
- Subjects
musculoskeletal diseases ,Carpal Joint ,medicine.medical_specialty ,Percutaneous ,business.industry ,medicine.medical_treatment ,Scaphoid fracture ,General Medicine ,Wrist ,Bone grafting ,medicine.disease ,Surgery ,03 medical and health sciences ,surgical procedures, operative ,0302 clinical medicine ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,medicine ,Internal fixation ,030212 general & internal medicine ,business ,Cancellous bone ,Fixation (histology) - Abstract
Rationale The treatment methods of pediatric scaphoid nonunion are still controversial. To our knowledge, arthroscopic-assisted treatments for pediatric scaphoid nonunion has not been reported in the English-language literature. Therefore, the purpose of this study is to report the use of arthroscopic-assisted bone grafting for scaphoid nonunion fracture in 3 patients and present a literature review. Patients concerns Two 15-year-old patients developed carpal joint injuries over a year, prior to their hospital presentation, since they had not received adequate treatment. The third patient, 12 years of age, was diagnosed with scaphoid fracture after a traffic accident and underwent conservative treatment but presented to the hospital due to issues related with bone union. Diagnosis All 3 patients were diagnosed with scaphoid nonunion at our hospital, using plain wrist radiographs and computed tomography. Interventions All the patients underwent arthroscopic debridement; 2 patients received autogenous iliac cancellous bone graft, while the other patient received a bone substitute graft. The internal fixation of the scaphoid was performed with K-wires. Outcomes Bone unions were achieved in all patients, and the final follow-up resulted in successful outcomes. Lessons Arthroscopic-assisted bone grafting and percutaneous K-wire fixation can be considered as a good method for the treatment of pediatric scaphoid nonunion fractures. Therefore, it is a primary treatment option for symptomatic scaphoid nonunion fracture and displaced fractures.
- Published
- 2021
49. Clinical Outcomes of Nonoperative Treatment for Rotator Cuff Retears and Analysis of Factors That Affect Outcomes
- Author
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Jaewoo Shim, Young Keun Lee, and Jae Chul Yoo
- Subjects
arthroscopic surgery ,medicine.medical_specialty ,medicine.diagnostic_test ,shoulder ,business.industry ,Magnetic resonance imaging ,rotator cuff repair ,Affect (psychology) ,Article ,Nonoperative treatment ,Surgery ,medicine.anatomical_structure ,medicine ,magnetic resonance imaging ,Orthopedics and Sports Medicine ,Rotator cuff ,retear ,business - Abstract
Background: Patients who sustain a rotator cuff retear after arthroscopic rotator cuff repair are generally considered to have worse clinical outcomes compared with patients with an intact rotator cuff. However, some patients have good clinical outcomes, even with a retorn rotator cuff. Purpose: To report the clinical outcomes of nonoperative treatment for rotator cuff retears and analyze the factors affecting clinical outcomes after a retear. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent arthroscopic rotator cuff repair between 2011 and 2017 were reviewed, and those with a full-thickness retear on postoperative magnetic resonance imaging (MRI) were included in this study. According to their pre- and postoperative scores on the pain visual analog scale (pVAS) and functional visual analog scale (fVAS), the patients were divided into 3 groups: (1) mild group (pVAS ≤ 1 and fVAS ≥ 8), (2) moderate group (pVAS ≤ 1 and fVAS ≤ 7 or pVAS 2-3 and fVAS ≥ 8), and (3) severe group (pVAS ≥ 3 and fVAS ≤ 7). Preoperative data (dominant hand involvement, heavy labor) and tear size on 6-month postoperative MRI were analyzed as factors affecting clinical outcomes. Results: A total of 712 patients were reviewed, and a retear was observed in 62 patients (8.7%). Of the patients with retears, 52 were included in this study: 25 men and 27 women with a mean age of 62.6 years (range, 49-80 years) and mean follow-up period of 40 months (range, 24-88 months). According to the pVAS and fVAS scores, 25 patients (48.1%) were classified into the mild group, 9 (17.3%) into the moderate group, and 18 (34.6%) into the severe group. There were no significant differences in preoperative data among the 3 groups. The tear size in the coronal and sagittal planes decreased by 5.1 and 6.6 mm, respectively, in the mild group but increased by 2.8 and 1.4 mm, respectively, in the severe group. Conclusion: In patients with retears, 48.1% had only mild symptoms at a mean of 40 months postoperatively. Patients with severe symptoms tended to have an increased tear size on postoperative MRI.
- Published
- 2020
50. Use of Artificial Neural Network for the Simulation of Radon Emission Concentration of Granulated Blast Furnace Slag Mortar
- Author
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Seungyoung So, Malrey Lee, Young-Keun Lee, Hong-Seok Jang, and Shuli Xing
- Subjects
Cement ,Materials science ,Artificial neural network ,Metallurgy ,Biomedical Engineering ,chemistry.chemical_element ,Bioengineering ,Radon ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Indoor air quality ,chemistry ,Ground granulated blast-furnace slag ,General Materials Science ,Mortar ,0210 nano-technology ,Cement mortar - Abstract
In this study, an artificial neural networks study was carried out to predict the quantity of radon of Granulated Blast Furnace Slag (GBFS) cement mortar. A data set of a laboratory work, in which a total of 3 mortars were produced, was utilized in the Artificial Neural Networks (ANNs) study. The mortar mixture parameters were three different GBFS ratios (0%, 20%, 40%). Measurement radon of moist cured specimens was measured at 3, 10, 30, 100, 365 days by sensing technology for continuous monitoring of indoor air quality (IAQ). ANN model is constructed, trained and tested using these data. The data used in the ANN model are arranged in a format of two input parameters that cover the cement, GBFS and age of samples and, an output parameter which is concentrations of radon emission of mortar. The results showed that ANN can be an alternative approach for the predicting the radon concentration of GBFS mortar using mortar ingredients as input parameters.
- Published
- 2016
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