• Journal of Chest Surgery
• /
• 제48권6호
• /
• pp.381-386
• /
• 2015

Background: Postinfarction ventricular septal defects (pVSDs) are a serious complication of acute myocardial infarctions. The aim of this study was to analyze the clinical outcomes of the surgical treatment of pVSDs. Methods: The medical records of 23 patients who underwent operations (infarct exclusion in 21 patients and patch closure in two patients) to treat acute pVSDs from 2001 to 2011 were analyzed. Intra-aortic balloon counterpulsation was performed in 19 patients (82.6%), one of whom required extracorporeal membrane support due to cardiogenic shock. The mean follow-up duration was $26.2{\pm}18.6months$. Results: The in-hospital mortality rate was 4.3% (1/23). Residual shunts were found in seven patients and three patients required reoperation. One patient needed reoperation due to the transformation of an intracardiac hematoma into an abscess. No patients required reoperation due to recurrence of a ventricular septal defect during the follow-up period. The cumulative survival rate was 95.5% at one year, 82.0% at five years, and 65.6% at seven years. Conclusion: The use of a multiple-patch technique with sealants appears to be a reliable method of reducing early mortality and the risk of significant residual shunting in patients with pVSDs.

• 대한두개안면성형외과학회지
• /
• 제21권4호
• /
• pp.237-243
• /
• 2020

Background: The scalp is an important functional and aesthetic structure that protects the cranial bone. Due to its inelastic characteristics, soft-tissue defects of the scalp make reconstruction surgery difficult. This study aims to provide an improved scalp reconstruction decision making algorithm for surgeons. Methods: This study examined patients who underwent scalp reconstruction within the last 10 years. The study evaluated several factors that surgeons use to select a given reconstruction method such as etiology, defect location, size, depth, and complications. An algorithmic approach was then suggested based on an analysis of these factors. Results: Ninety-four patients were selected in total and 98 cases, including revision surgery, were performed for scalp reconstruction. Scalp reconstruction was performed by primary closure (36.73%), skin graft (27.55%), local flap (17.34%), pedicled regional flap (15.30%), and free flap (3.06%). The ratio of primary closure to more complex procedure on loose scalps (51.11%) was significantly higher than on tight scalps (24.52%) (p=0.011). The choice of scalp reconstruction method was affected significantly by the defect size (R=0.479, p<0.001) and depth (p<0.001). There were five major complications which were three cases of flap necrosis and two cases of skin necrosis. Hematoma was the most common of the 29 minor complications reported, followed by skin necrosis. Conclusion: There are multiple factors affecting the choice of scalp reconstruction method. We suggest an algorithm based on 10 years of experience that will help surgeons establish successful surgical management for their patients.

• 한국정밀공학회지
• /
• 제32권6호
• /
• pp.529-536
• /
• 2015

A defect could be generated in bolts for a use of oil filters for the manufacturing process and then may affect to the safety and quality in bolts. Also, fine defects may be imbedded in oil filter system. So it is very important that such defects be investigated and screened during the multiple manufacturing processes. Therefore, in order effectively to evaluate the fine defects, the FEM simulations were performed to make characterization in the crack detection of the bolts and the parameters such as number of turns of the coil, the coil size, applied frequency were calculated based on the simulation results. Simulations were carried out for the defect signal of eddy current probe. Exciter and receiver were utilized. In this paper, the FEM simulations were performed in both bobbin-type and pancake-type probe, both probes were optimized under Eddy current FEM simulations and the results of calculation were discussed.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제27권5호
• /
• pp.431-437
• /
• 2005

Fibrin glue is composed of fibrinogen and thrombin and used in various regions for multiple use. Basic principle is that thrombin converts fibrinogen to fibrin in the presence of $Ca^{2+}$. The structure of fibrin is loose at the beginning, but after about 5 minutes a tight structure is formed under the influence of factor VIII which changes fibrin monomer into fibrin polymer. Fibrin glue is used for tissue adhesive, suture, local hemostasis, wound healing, closure of subdural space. Fibrin adhesive has been used in oral and maxillofacial surgery for hemostasis after tooth extraction in patients with coagulation disorders, skin graft fixation, reattachment of periodontal flaps, in combination with autogenous bone chips to fill the bony cavities following cyst removal, and for securing the hydroxyapatite granules for maxillary alveolar ridge augmentation. This study was designed for researching influence of fibrin glue during healing phase after making artificial bone defect.

• 한국재료학회지
• /
• 제23권10호
• /
• pp.550-554
• /
• 2013

As continued scaling becomes increasingly difficult, 3D integration has emerged as a viable solution to achieve higher bandwidths and good power efficiency. 3D integration can be defined as a technology involving the stacking of multiple processed wafers containing integrated circuits on top of each other with vertical interconnects between the wafers. This type of 3D structure can improve performance levels, enable the integration of devices with incompatible process flows, and reduce form factors. Through silicon vias (TSVs), which directly connect stacked structures die-to-die, are an enabling technology for future 3D integrated systems. TSVs filled with copper using an electro-plating method are investigated in this study. DC and pulses are used as a current source for the electro-plating process as a means of via filling. A TiN barrier and Ru seed layers are deposited by plasma-enhanced atomic layer deposition (PEALD) with thicknesses of 10 and 30 nm, respectively. All samples electroplated by the DC current showed defects, even with additives. However, the samples electroplated by the pulse current showed defect-free super-filled via structures. The optimized condition for defect-free bottom-up super-filling was established by adjusting the additive concentrations in the basic plating solution of copper sulfate. The optimized concentrations of JGB and SPS were found to be 10 and 20 ppm, respectively.

• Smart Structures and Systems
• /
• 제22권4호
• /
• pp.481-493
• /
• 2018

Ultrasonic guided waves have attracted increasing attention for non-destructive testing (NDT) and structural health monitoring (SHM) of bridge cables. They offer advantages like single measurement, wide coverage of acoustical field, and long-range propagation capability. To design defect detection systems, it is essential to understand how guided waves propagate in cables and how to select the optimal excitation frequency and mode. However, certain cable characteristics such as multiple wires, anchorage, and polyethylene (PE) sheath increase the complexity in analyzing the guided wave propagation. In this study, guided wave modes for multi-wire bridge cables are identified by using a semi-analytical finite element (SAFE) technique to obtain relevant dispersion curves. Numerical results indicated that the number of guided wave modes increases, the length of the flat region with a low frequency of L(0,1) mode becomes shorter, and the cutoff frequency for high order longitudinal wave modes becomes lower, as the number of steel wires in a cable increases. These findings were used in design of transducers for defect detection and selection of the optimal wave mode and frequency for subsequent experiments. A magnetostrictive transducer system was used to excite and detect the guided waves. The applicability of the proposed approach for detecting and locating wire breakages was demonstrated for a cable with 37 wires. The present ultrasonic guided wave method has been found to be very responsive to the number of brokenwires and is thus capable of detecting defects with varying sizes.

• 전기전자학회논문지
• /
• 제20권3호
• /
• pp.310-313
• /
• 2016

본 논문에서는 48개 채널의 GM Tube 센서 테스터 장치를 설계한다. 제안하는 장치는 48 채널의 GM Tube 센서들을 동시에 테스트하여 불량의 여부 및 센서 특성을 분석한다. 시간의 변화에 따라 달라지는 센서의 특성에 적합한 300 ~ 1000V의 가변 고전압을 발생할 수 있는 회로로 센서의 특성을 분석한다. 따라서 다양한 종류의 GM Tube 센서의 특성 분석에 용이하게 사용된다. 제안하는 장치를 통해 대량의 GM Tube를 동시에 테스트 할 수 있는 환경이 구축되어 센서의 불량 여부 및 센서의 특성을 미리 파악하여 생산 및 재작업 등에 소요되는 비용을 대폭 줄일 수 있다. 개발된 48 채널 GM Tube 센서 테스터 장치의 측정 불확도에 대하여 공인 시험기관의 장비를 사용하여 실험한 결과 우수한 성능을 나타내었다.

• Journal of Periodontal and Implant Science
• /
• 제52권6호
• /
• pp.466-478
• /
• 2022

Purpose: Coronally advanced split-or full-thickness (CAST or CAFT) flaps in combination with subepithelial connective tissue grafts (SCTGs) are commonly used in root-coverage procedures despite postoperative pain and bleeding from the graft donor site. Therefore, the modified vestibular incision subperiosteal tunnel access procedure (VISTAX) uses a novel collagen matrix (VCMX) instead of autogenous tissue to address the limitations associated with autogenous tissue grafting. This retrospective study compared the clinical outcomes of VISTAX to the results obtained after using a CAST or CAFT flap in combination with SCTG for root coverage. Methods: Patients with single or multiple adjacent recession I/II defects were included, with 10 subjects each in the VISTAX, CAFT, and CAST groups. Defect coverage, keratinized tissue width, esthetic scores, and patients' perceived pain and dentinal hypersensitivity (visual analogue scale [VAS]) were assessed at baseline, 3 months, and 6 months. Results: All surgical techniques significantly reduced gingival recession (P<0.0001). Defect coverage, esthetic appearance, and the reduction in dentinal hypersensitivity were comparable. However, the VAS scores for pain were significantly lower in the VISTAX group than in the CAFT and CAST groups, which had similar scores (P<0.05). Furthermore, the clinical results of VISTAX and CAFT/CAST generally remained stable at 6 months. Conclusions: The clinical outcomes of VISTAX, CAFT, and CAST were comparable. However, patients perceived significantly less pain after VISTAX, indicating a potentially higher patient acceptance of the procedure. A prospective trial with a longer follow-up period and a larger sample size should therefore evaluate VISTAX further.

• Journal of Chest Surgery
• /
• 제38권10호
• /
• pp.725-728
• /
• 2005

환아는 생후 18개월 된 여아로 반복적인 위급한 과량의 객혈을 주소로 입원하였다. 과거력상 생후 6개월에 중증의 심비대 소견을 보이는 심방중격결손증을 진단받았으며 폐정맥 협착이 심비대에 의한 압박으로 생긴 이차적인 병변일 것이라 추정하여 심방중격결손폐쇄술만 시행하였다. 술 후 환아는 심비대와 폐정맥 협착이 완화된 소견을 보였다. 그러나 추적 관찰 중 환아는 반복적인 다량의 객혈로 다시 입원하였고 전산화단충촬영 소견 상 폐정맥 협착이 다시 심해진 것으로 판독되었으며 기관지 주변에 성상을 알 수 없는 연조직 종괴들이 좌측 기관지를 압박하고 있었다. 정확한 위치를 알 수 없는 반복적인 객혈로 인해 시험적 개흉술이 불가피하였고, 수술 소견상 좌폐정맥은 하나였으며 외견상 협착의 소견을 보였다. 좌측 기관지 주변에는 다발성 임파절 비대가 기관지를 압박하고 있었다. 또한 수술 중 다량의 객혈이 발생하여 전폐절제술을 시행할 수밖에 없었다. 술 후 병리 소견은 폐정맥 협착과 일치하였다. 환아는 2일간의 중환자실 관리 후 6일째 합병증 없이 퇴원하였다. 2개월간 추적 관찰되었으며 증상 없이 양호한 경과를 보이고 있다. 그러나 향후 지속적인 추적 관찰이 필요할 것으로 생각한다.

• Journal of Periodontal and Implant Science
• /
• 제29권3호
• /
• pp.507-519
• /
• 1999

The ultimate objective of periodontal treatment is to stop disease progression and to regenerate destroyed periodontal tissues and thereby regain normal function. Growth factors are naturally found polypetides which stimulate many cellular activities pertaining to wound healing by acting as signal molecule in controlling cell movement, proliferation, and matrix production. Platelet derived growth factor (PDGF) is 28,000-35,000 Da molecular weight dimeric protein with 2 long positively charged polypeptide chains connected by sulfide bonds. The purpose of this study is to evaluate histologically the initial guided tissue regeneration in a periodontal defect f a beagle dog treated with a biodegradable membrane formed with polylactic acid (poly-L-lactic acid) and polyglycolic acid loaded with 200ng/$cm^2$ platelet derived growth factor. 2 beagle dogs were used in he experiment. $5mm{\times}6mm$ alveolar bone defect was formed in upper and lower canines and third premolars and a reference notch was placed. PDGF-BB non-containing membrane was used as control. Each defect was randomly assigned to the test roup or the control group. The dogs were sacrificed 3 weeks after membrane placement. Toluidine blue and multiple staining was done for histological analysis. In the 3 week specimen in the control group, no new one formation could be seen. Small amount f bone resorption below the notch could be seen. In the notch, loose connective tissue with infiltration of inflammatory cells could be seen. Also thin discontinuous new cementum could be seen and the membrane still retained its structure. Where PDGF-BB containing membrane was used, new bone formation could be seen in the notch at weeks and also continuous thin cementum could be seen. PDL cells were observed between new bone and new cementum and some were attached to bone and cementum. These results suggest that new bone and cementum formation seen when PDGF-BB loaded membrane was used was due to inhibition of downgrowth of epithelial cells and also due to continuous release of the growth factor. Further study on the resorption characteristics of the membrane nd the release characteristics of the PDGF-BB is necessary. Also, development of a membrane easier to use clinically is necessary.