• Journal of the Korean Orthopaedic Association
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• v.54 no.6
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• pp.475-477
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• 2019

Stem cell research arose from the need to explore new therapeutic possibilities for intractable and lethal diseases. Although musculoskeletal disorders are basically nonlethal, their high prevalence and the relative ease of performing clinical trials have facilitated the clinical application of stem cells in this field. On the other hand, despite the plethora of in vitro and preclinical studies in stem cell research for regenerative medicine in the musculoskeletal system, few reliable clinical studies have been published. Stem cell therapy can be applied locally for bone, cartilage, and tendon regeneration. The candidate disease modalities in bone regeneration include large bone defects, nonunion of fractures, and osteonecrosis. Focal osteochondral defect and osteoarthritis are the current targets for cartilage regeneration. For tendon regeneration, bone-tendon junction problems, such as rotator cuff tears are hot topics in clinical research. To date, the literature supporting stem cell-based therapies comprises mostly case reports or case series.

• Medical Lasers
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• v.8 no.1
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• pp.7-12
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• 2019

Background and Objectives Skin and soft tissue defects can be treated according to a range of strategies, such as local flap, skin graft, biological dressing, or free flap. On the other hand, free tissue transfer usually leaves a distinct scar with an inconsistency of color or hypertrophy. This problem is highlighted if the defect is located on the face, which could have devastating effects on a patient's psychosocial health. Materials and Methods The authors used an erbium : yttrium-aluminum-garnet (Er:YAG) laser to resurface the free flap skin and match the color with the surrounding facial skin. This study evaluated the effectiveness of laser skin resurfacing on the harmonious color matching of transferred flap. Patients who had undergone laser resurfacing on facial flap skin between January 2014 and December 2018 were reviewed retrospectively. An ablative 2,940-nm fractional Er:YAG laser treatment was delivered to the entire flap skin at 21 J/cm² with the treatment end-point of pinpoint bleeding. Several months later, the clinical photographs were analyzed. The L^*a^*b^* color co-ordinates of both the flap and surrounding normal skin were measured using Adobe Photoshop. The L^*a^*b^* color difference (ΔE) for the scar and normal surrounding skin were calculated using the following equation: ${\Delta}E=\sqrt{({\Delta}L)^2+({\Delta}a)^2+({\Delta}b)^2}$ Results All five patients were satisfied with the more natural appearance of the flaps. The ΔE values decreased significantly from the pre-treatment mean value of 19.64 to the post-treatment mean value of 11.39 (Wilcoxon signed-rank test, p = 0.043). Conclusion Ablative laser resurfacing can improve the aesthetic outcome of free tissue transfer on the face.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.100-107
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• 2003

Purpose : To assess the usefulness of cardiac MR imaging (MRI) in the diagnosis of acute myocardial infarction and in the assessment of myocardial viability in comparision with T1-201 SPECT. Materials and Methods : We retrospectively studied 17 patients who complained of chest pain and dyspnea with cardiac MRI . The patients were evaluated for the presence or absence of high signal intensity on T2-weighted image (T2wI), abnormal wall motion on 2D-FIESTA, perfusion defect on Gd-DTPA enhanced T1WI, and delayed myocardial enhancement on 15-minutes delay Gd-DTPA enhanced T1WI. The results were correlated with the images on T1-201 SPECT, taken at rest and stress, through which reversibility of perfusion defect was assessed. Results : Both cardiac MRI and T1-201 SPECT proved to be useful methods for diagnosing acute myocardial infarction. In order of decreasing correspondence, T2WI, T1-201 SPECT, delayed enhancement study, and wall motion images all showed significant statistical correlation with the clinical diagnosis of myocardial infarction. Perfusion MRI, on the other hand, showed no significant statistical difference was found between T1-201 SPECT and cardiac MRI. The results on T2WI showed high accordance with those on Tl-201 SPECT, while delayed myocardial enhancement and wall motion studies showed no agreement with Tl-201 SPECT. Conclusion : Cardiac MRI is useful method for diagnosis of acute myocardiac infarction. With respect to the assessment of myocardial viability, the results obtained on cardiac MRI showed high agreement with those on Tl-201 SPECT. However, further study is necessary at this point for standardization and establishment of the methods for assessing myocardial viability on cardiac MRI.

• Journal of the Korean Orthopaedic Association
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• v.55 no.3
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• pp.253-260
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• 2020

Purpose: Soft tissue defects of the distal lower extremity are commonly accompanied by a fracture of the lower extremities. Theses defects are caused by the injury itself or by complications associated with surgical treatment of the fracture, which poses challenging problem. The reverse superficial sural artery flap (RSSAF) is a popular option for these difficult wounds. This paper reviews these cases and reports the clinical results. Materials and Methods: Between August 2003 and April 2018, patients who were treated with RSSAF for soft tissue defects of the lower third of the leg and ankle related to a fracture were reviewed. A total of 16 patients were involved and the mean follow-up period was 18 months. Eight cases (50.0%) of the defects were due to an open fracture, whereas the other eight cases (50.0%) were postoperative complication after closed fracture. The largest flap measured 10×15 cm² and the mean size of the donor sites was 51.9 cm². The flap survival and postoperative complications were evaluated. Results: All flaps survived without complete necrosis or failure. One case with partial necrosis of the flap was encountered, but the wound healed after debridement and repair. One case had a hematoma with a pseudoaneurysmal rupture of the distal tibial artery. On the other hand, the flap was intact and the wound healed after arterial ligation and flap advancement. A debulking operation was performed on three cases for cosmetic reasons and implant removal through the flap was performed in three cases. No flap necrosis was encountered after these additional operations. Conclusion: RSSAF is a relatively simple and safe procedure for reconstructing soft tissue defects following a fracture of the lower extremity that does not require microsurgical anastomosis. This can be a useful treatment option for soft tissue defects on the distal leg, ankle, and foot.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.404-412
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• 2021

Purpose: This study examined the degree of cartilage regeneration by performing second-look arthroscopy in a group of patients who underwent high tibial osteotomy and microfractures for unicompartmental osteoarthritis of the medial knee joint and to determine the factors affecting cartilage regeneration. In addition, this study analyzed whether there is a relationship between the degree of cartilage regeneration and functional results. Materials and Methods: From 2007 to 2015, this study evaluated 81 cases who underwent second-look arthroscopy at the time of plate removal after a microfracture and high tibial osteotomy with a minimum two-year follow-up. The degree of femoral cartilage injury before surgery was classified by ICRS (International Cartilage Research Society), and all were grade III and IV. After second-look arthroscopy, cartilage regeneration was classified into a well-regenerated group (grade I, II) and a poorly regenerated group (grade III, IV). The independent factors influencing cartilage regeneration were identified through multivariate logistic regression analysis. In addition, the functional results were compared before and after surgery between the two groups using the Knee Society score (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index score (WOMAC). Results: Age, sex, body mass index, postoperative radiologic factors, and preoperative joint condition did not affect the degree of cartilage regeneration significantly. The large cartilage defect (≥2.0 cm²) (p=0.011) and the presence of kissing lesions (p=0.027) were associated with poor cartilage regeneration. No significant difference in the KSS and WOMAC scores was observed between the group with good and poor cartilage regeneration. Conclusion: The presence of a large cartilage defect and kissing lesions is associated with poor cartilage regeneration after high tibial osteotomy and microfracture. On the other hand, the degree of the regenerated cartilage did not show any correlation with the functional outcome.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.4
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• pp.348-355
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• 2006

Tennison was the first to recognize and to preserve the Cupid's bow by lowering the peak in the margin of the cleft. Randall had modified the Tennison's repair based on accurate measurements. Bardach's technique evolved from the basic concept of triangular flap cleft lip repair described by Tennison-Randall method. Precise measurements are used to define the dimensions of the equilateral triangular flap, which is created on the cleft side and is inserted into an equilateral triangular defect on the noncleft side. Two symmetrical vertical distances on either side of the cleft are thus formed. It is essential that the incisions in the skin correspond precisely with those on the muscles and mucosa, and that all layers are sutured with the use of the triangular flap, thus preventing vertical scar contracture. This procedure produces a symmetric, balance lip with a well-defined Cupid's bow, a symmetric vermilion, and a properly aligned orbicularis oris muscle. We had treated three patients with unilateral incomplete cleft lip by using Bardach's triangular flap method. The operation scars could be reduced comparing to Millard method because Bardach's method did not use the columella base and the alar base incision. And the flap design was more simple and accurate comparing to Tennison-Randall method. On the other hand, the postoperative scars on the philtrum pointed as a disadvantage of triangular flap method were cosmetically acceptable because the three patients had incomplete cleft lip. We have experienced that Bardach's triangular flap is a recommendable technique for the repair of unilateral incomplete cleft lip.

• Membrane Journal
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• v.24 no.5
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• pp.375-385
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• 2014

NaA zeolite/${\alpha}$-alumina composite membranes were hydrothermally synthesized at $100^{\circ}C$ for 24 hr by using nanosize seed of 100 nm in diameter and an ${\alpha}$-alumina support of $0.1{\mu}m$ in pore diameter, and then effect of seed coating layer on the microstructure of NaA zeolite separation layer was systematically investigated. In cases when nanosize seed was coated with a monolayer, increment in seed coverage induced small grained and thick NaA zeolite separation layer. On the other hand, in case when nanosize seed was coated with a multilayer, much small grained and thick separation layer was formed. It was clear that an uniform monolayer seed coating is required to grow hydrothermally a thin and defect-free NaA zeolite separation layer. In the present study, it was clearly announced that seed coating layer is a key factor to determine the microstructure of NaA zeolite layer, secondary grown on a porous support.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.1
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• pp.57-64
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• 2015

Activity recognition technology is gaining attention because it can provide useful information follow user's situation. In research of activity recognition before smartphone's dissemination, we had to infer user's activity by using independent sensor. But now, with development of IT industry, we can infer user's activity by using inner sensor of smartphone. So, more animated research of activity recognition is being implemented now. By applying activity recognition system, we can develop service like recommending application according to user's preference or providing information of route. Some previous activity recognition systems have a defect using up too much energy, because they use GPS sensor. On the other hand, activity recognition system which Google released recently (Google Activity Recognition) needs only a few power because it use 'Network Provider' instead of GPS. Thus it is suitable to smartphone application system. But through a result from testing performance of Google Activity Recognition, we found that is difficult to getting user's exact activity because of unnecessary activity element and some wrong recognition. So, in this paper, we describe problems of Google Activity Recognition and propose AGAR(Advanced Google Activity Recognition) applied method to improve accuracy level because we need more exact activity recognition for new service based on activity recognition. Also to appraise value of AGAR, we compare performance of other activity recognition systems and ours and explain an applied possibility of AGAR by developing exemplary program.

• Archives of Plastic Surgery
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• v.38 no.6
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• pp.798-802
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• 2011

Purpose: A wart is caused by epidermal infection with the human papilloma virus. Although wart naturally disappears in some cases, it require treatment because of pain, aesthetic problem, and the possibility of malignant change. Conventional non-surgical treatment cannot be a fundamental solution for the pain and has such disadvantages as frequent recurrence and difficulties in achieving a satisfactory outcome. A surgical procedure was performed on patients with wart and the procedure had a good outcome. Methods: We investigated the gender, age, lesion site, mean treatment duration, and presence or absence of recurrence in 21 patients with a wart within the period of January 2007 to July 2011. For local lesions, primary closure, including subcuticular suture after the excision, was performed. If the defect size was too big to do primary closure, we performed rotation flap. For wide multiple lesions, a split thickness skin graft was performed. Results: Among the 21 patients, 12 patients were male and 9 patients were female, and their mean age was 42 years (SD=17.38, range: 11~75 years). The lesion site was the foot in 10 patients, the hand in 8 patients, the face in 2 patients, and the scalp in 1 patient. The mean treatment duration was 13.5 days (SD=4.36, range: 6~15 days) for the primary closure or rotation flap, and 18.5 days (SD=2.12, range: 17~20 days) for the skin graft. 20 patients were cured without recurrence. No recurrence was observed in the patients who underwent primary closure or rotation flap. One of the two patients who underwent a skin graft of their wart that had covered their entire palm had local recurrence in part of her finger tips. Conclusion: We performed surgical procedure on recalcitrant wart. As a results, we can treat it with short treatment duration, low recurrence rate and less scarring and get high patient satisfaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.395-399
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• 2017

The LPI fuel filter housings used in automobiles were made from conventional die castings but have recently been developed by cold forging to improve the weight and durability. On the other hand, a sink may develop at the core of the forged product due to the resulting T-shape, which not only reduces the aesthetics, but also increases the post-processing cost of the product. Therefore, this research focused on methods to predict and mitigate sink development and progression during the T-shape forging process. Finite element analysis of the forging process was first performed to determine the optimal initial workpiece devoid of burrs and underfills. An accurate sink prediction was then obtained via metal flow analysis, which was a result of the finite element simulation. Through finite element analysis, it was confirmed that sink development is a product of the differences in nodal velocities arising from the T-shaped forging process. Consequently, a pad was inserted beneath the sink to minimize these velocity differences. The results yielded significant improvement with regard to the sink defect. This method was practically applied to an industrial site to validate the sink improvement.