• Archives of Reconstructive Microsurgery
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• 제8권2호
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• pp.184-191
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• 1999

Reconstruction of soft tissue defect of the foot, ankle and distal tibial area has been and remains a challenging problem for reconstructive surgeons. We treated 19 patients who showed soft tissue defect in these area with distally based superficial sural artery flaps, including four adipofascial flaps, two sensate flaps. The size of the soft tissue defect was from $4{\times}5cm\;to\;8{\times}10cm$. In nine cases, we preserved sural nerve. Seventeen flaps survived completely, but one flap failed and another flap showed partial skin necrosis at the distal half. In failed cases, lesser saphenous vein was ruptured at initial injury. The advantage of this flap is a constant and reliable blood supply without sacrifice of major artery or sensory nerve. Elevation of the flap is technically easy and quick. The pedicle is long and the island flap can be transffered as far as to the instep area. It also has the potential for sensate flap, innervated by the lateral sural cutaneous nerve. But for appropriate venous drainage small saphenous vein must be preserved.

• 정보처리학회 논문지
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• 제13권5호
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• pp.236-242
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• 2024

소프트웨어 결함 예측(SDP)은 오류가 발생할 가능성이 있는 모듈을 사전에 식별하여 소프트웨어 개발의 효율을 높이고 있다. SDP에서의 주과제는 예측 성능을 향상시키는것에 있다. 최근 연구에서는 딥러닝 기법이 소프트웨어 결함 예측(SDP) 분야에 적용되어 있으며, 특히 구조화된 데이터를 분석하는 데 뛰어난 성능을 보이고 있는 SAINT 모델이 주목받고 있다. 본 연구는 SAINT 모델을 다른 주요 모델(XGBoost, Random Forest, CatBoost)과 비교하여 SDP에 적용 가능한 최신 딥러닝 기법을 조사하였다. SAINT는 일관되게 우수한 성능을 보여주며 결함 예측 정확도 향상에 효과적임을 입증하였다. 이 연구 결과는 실용적인 소프트웨어 개발 상황에서 결함 예측 방법론을 발전시킬 수 있는 SAINT의 잠재력을 강조하며, 교차 검증, 특성 스케일링, 비교 분석 등을 포함한 철저한 방법론을 통해 수행되었다.

• Journal of Periodontal and Implant Science
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• 제49권2호
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• pp.114-126
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• 2019

Purpose: The aim of this study was to evaluate the enhancement of osteogenic potential of biphasic calcium phosphate (BCP) bone substitute coated with Escherichia coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2) and epigallocatechin-3-gallate (EGCG). Methods: The cell viability, differentiation, and mineralization of osteoblasts was tested with ErhBMP-2-/EGCG solution. Coated BCP surfaces were also investigated. Standardized, 6-mm diameter defects were created bilaterally on the maxillary sinus of 10 male New Zealand white rabbits. After removal of the bony windows and elevation of sinus membranes, ErhBMP-2-/EGCG-coated BCP was applied on one defect in the test group. BCP was applied on the other defect to form the control group. The animals were sacrificed at 4 or 8 weeks after surgery. Histologic and histometric analyses of the augmented graft and surrounding tissue were performed. Results: The 4-week and 8-week test groups showed more new bone (%) than the corresponding control groups (P<0.05). The 8-week test group showed more new bone (%) than the 4-week test group (P<0.05). Conclusions: ErhBMP-2-/EGCG-coated BCP was effective as a bone graft material, showing enhanced osteogenic potential and minimal side effects in a rabbit sinus augmentation model.

• 대한두개안면성형외과학회지
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• 제22권5호
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• pp.260-267
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• 2021

Background: Elastic ear cartilage is a good source of tissue for support or augmentation in plastic and reconstructive surgery. However, the amount of ear cartilage is limited and excessive use of cartilage can cause deformation of the auricular framework. This animal study investigated the potential of periosteal chondrogenesis in an ear cartilage defect model. Methods: Twelve New Zealand white rabbits were used in the present study. Four ear cartilage defects were created in both ears of each rabbit, between the central artery and marginal veins. The defects were covered with perichondrium (group 1), periosteum taken from the calvarium (group 2), or periosteum taken from the tibia (group 3). No coverage was performed in a control group (group 4). All animals were sacrificed 6 weeks later, and the ratio of neo-cartilage to defect size was measured. Results: Significant chondrogenesis occurred only in group 1 (cartilage regeneration ratio: mean±standard deviation, 0.97±0.60), whereas the cartilage regeneration ratio was substantially lower in group 2 (0.10±0.11), group 3 (0.08±0.09), and group 4 (0.08±0.14) (p= 0.004). Instead of chondrogenesis, osteogenesis was observed in the periosteal graft groups. No statistically significant differences were found in the amount of osteogenesis or chondrogenesis between groups 2 and 3. Group 4 showed fibrous tissue accumulation in the defect area. Conclusion: Periosteal grafts showed weak chondrogenic potential in an ear cartilage defect model of rabbits; instead, they exhibited osteogenesis, irrespective of their embryological origin.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.420-420
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• 2013

We investigated oxygen plasma effect on defect states near the interface of AlGaN/GaN High Electron Mobility Transistor (HEMT) structure grown on a silicon substrate. After the plasma treatment, electrical properties were evaluated using a frequency dependant Capacitance-Voltage (C-V) and a temperature dependant C-V measurements, and a deep level transient spectroscopy (DLTS) method to study the change of defect densities. In the depth profile resulted from the temperature dependant C-V, a sudden decrease in the carrier concentration for two-dimensional electron gas (2DEG) nearby 250 K was observed. In C-V measurement, the interface states were improved in case of the oxygen-plasma treated samples, whereas the interface was degraded in case of the nitrogen-plasma treated sample. In the DLTS measurement, it was observed the two kinds of defects well known in AlGaN/GaN structure grown on sapphire substrate, which have the activation energies of 0.15 eV, 0.25 eV below the conduction band. We speculate that this defect state in AlGaN/GaN on the silicon substrate is caused from the decrease in 2DEG's carrier concentrations. We compared the various DLTS signals with filling pulse times to identify the characteristics of the newly found defect. In the filling pulse time range under the 80 us, the activation energies changed as the potential barrier model. On the other hand, in the filling pulse time range above the 80 us, the activation energies changed as the extended potential model. Therefore, we suggest that the found defect in the AlGaN/GaN/Si structure could be the extended defect related with AlGa/N/GaN interface states.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.329-329
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• 2016

Large-area graphene films produced by means of chemical vapor deposition (CVD) are polycrystalline and thus contain numerous grain boundaries that can greatly degrade their performance and produce inhomogeneous properties. A better grain boundary engineering in CVD graphene is essential to realize the full potential of graphene in large-scale applications. Here, we report a defect-selective atomic layer deposition (ALD) for stitching grain boundaries of CVD graphene with ZnO so as to increase the connectivity between grains. In the present ALD process, ZnO with hexagonal wurtzite structure was selectively grown mainly on the defect-rich grain boundaries to produce ZnO-stitched CVD graphene with well-connected grains. For the CVD graphene film after ZnO stitching, the inter-grain mobility is notably improved with only a little change in free carrier density. We also demonstrate how ZnO-stitched CVD graphene can be successfully integrated into wafer-scale arrays of top-gated field effect transistors on 4-inch Si and polymer substrates, revealing remarkable device-to-device uniformity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.397-402
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• 2005

The NDT(Non-Destructive Testing) is valid for the defect detection of rolling stocks because it can be used to detect the defect in many invisible parts. For example, fatigue cracks are initiated in press fit parts that suffer from fretting fatigue damage such as the wheel seat and the NDT technique can detect those cracks. But the conventional ICFPD method can not apply to detect such cracks in press fit parts of the axle by some technical problems. In this study, we have introduced the new concept ICFPD method that can be applied in press fit parts of the axle. And we have shown the basic techniques of FEM about the new concept ICFPD method.

• 한국생산제조학회지
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• 제20권2호
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• pp.139-144
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• 2011

This paper presents a boundary element application to determine the optimal impressed current densities at defect position on the pipe line. In this protection paint, enough current must be impressed to lower the potential distribution on the metal surface to the critical values. The optimal impressed current densities are determined in order to minimize the power supply for protection. This inverse problem was formulated by employing the boundary element method. Since the system of linear equations obtained was ill-conditioned, including singular value decomposition, conjugate gradient method were applied and the accuracies of these estimation. Several numerical examples are presented to demonstrate the practical applicability of the proposed method.

• BMB Reports
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• 제48권11호
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• pp.597-598
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• 2015

Mitochondrial respiratory defect is a key bioenergetics feature of hepatocellular carcinoma (HCC) cells. However, their involvement and roles in HCC development and progression remain unclear. Recently, we identified 10 common mitochondrial defect (CMD) signature genes that may be induced by retrograde signaling-mediated transcriptional reprogramming in response to HCC mitochondrial defects. HCC patients with enriched expression of these genes had poor prognostic outcomes, such as shorter periods of overall survival and recurrence-free survival. Nuclear protein 1 (NUPR1), a key transcription regulator, was up-regulated by Ca⁺⁺-mediated retrograde signaling. NUPR1-centric network analysis and a biochemical promoter-binding assay demonstrated that granulin (GRN) is a key downstream effector of NUPR1 for the regulation of HCC cell invasiveness; association analysis of the NUPR1-GRN pathway supported this conclusion. Mitochondrial respiratory defects and retrograde signaling thus play pivotal roles in HCC progression, highlighting the potential of the NUPR1-GRN axis as a novel diagnostic marker and therapeutic target for HCC.

• Archives of Plastic Surgery
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• 제38권4호
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• pp.438-444
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• 2011

Purpose: Adipose-derived stromal cells (ASCs) are readily harvested from lipoaspirated tissue or subcutaneous adipose tissue fragments. The stromal vascular fraction (SVF) is a heterogeneous set of cell populations that surround and support adipose tissue, which includes the stromal cells, ASCs, that have the ability to differentiate into cells of several lineages and contains cells from the microvasculature. The mechanisms that drive the ASCs into the osteoblast lineage are still not clear, but the process has been more extensively studied in bone marrow stromal cells. The purpose of this study was to investigate the osteogenic capacity of adipose derived SVF cells and evaluate bone formation following implantation of SVF cells into the bone defect of human phalanx. Methods: Case 1 a 43-year-old male was wounded while using a press machine. After first operation, segmental bone defects of the left 3rd and 4th middle phalanx occurred. At first we injected the SVF cells combined with demineralized bone matrix (DBM) to defected 4th middle phalangeal bone lesion. We used P (L/DL)LA [Poly (70L-lactide-co-30DL-lactide) Co Polymer P (L/DL)LA] as a scaffold. Next, we implanted the SVF cells combined with DBM to repair left 3rd middle phalangeal bone defect in sequence. Case 2 was a 25-year-old man with crushing hand injury. Three months after the previous surgery, we implanted the SVF cells combined with DBM to restore right 3rd middle phalangeal bone defect by syringe injection. Radiographic images were taken at follow-up hospital visits and evaluated radiographically by means of computerized analysis of digital images. Results: The phalangeal bone defect was treated with autologous SVF cells isolated and applied in a single operative procedure in combination with DBM. The SVF cells were supported in place with mechanical fixation with a resorbable macroporous sheets acting as a soft tissue barrier. The radiographic appearance of the defect revealed a restoration to average bone density and stable position of pharyngeal bone. Densitometric evaluations for digital X-ray revealed improved bone densities in two cases with pharyngeal bone defects, that is, 65.2% for 4th finger of the case 1, 60.5% for 3rd finger of the case 1 and 60.1% for the case 2. Conclusion: This study demonstrated that adipose derived stromal vascular fraction cells have osteogenic potential in two clinical case studies. Thus, these reports show that cells from the SVF cells have potential in many areas of clinical cell therapy and regenerative medicine, albeit a lot of work is yet to be done.