• Composites Research
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• 제24권6호
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• pp.1-6
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• 2011

본 연구에서는 탄소나노튜브를 물상에서 균일하게 분산시키기 위하여 물에 녹으면서 분자 내에서 자체 도핑이 가능한 새로운 종류의 그래프트 공중합체(PSSA-g-PANI, poly(styrenesulfonic acid-graft-aniline))를 합성하였고, 그 분산 능력을 실험해 보았다. PANI 고분자는 벤조이드와 퀴노이드 구조가 반복되어 존재하는 판상구조로 탄소나노튜브와 같은 탄소나노 소재의 벽에 강하게 결합할 수 있고, 따라서 짧은 시간의 sonication 처리 만으로 나노튜브를 분산시킬 수 있었고 그 분산 용액의 장시간 안정성은 다른 상용화된 분산제보다 뛰어났다. 또한 PSSA-g-PANI 그래프트 고분자/탄소나노튜브 복합 필름은 대략 1.5-2.5 S/cm의 전도도를 기록하였다.

• Journal of Periodontal and Implant Science
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• 제37권2호
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• pp.151-164
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• 2007

Objective: The sinus floor elevation procedures have been used to facilitate implant placement in the severely atrophic posterior maxilla. Many variables may have an influence on the outcomes of the sinus floor elevation in combination with implant treatment. The aim of this study was to analyze survival rate of implants placed in the edentulous maxillae of patients in whom sinus floor elevation was undertaken according to variables. Materials and Methods: It consisted of 96 patients(50 male and 46 female), ranging in age from 31 to 70 years(mean 49 years), who underwent sinus floor elevation procedure(94 implants in left side and 106 implants in right side) from 2001 to 2002. A total of 200 implants were placed in the grafted sinus(73 implants in lateral approach and 127 implants in crestal approach). All implants were restored by fixed prosthesis. All patients were healthy. Follow-up periods for implants were between 48 to 60 months. Results: The cumulative survival rate of implants was 91.5%. Gender, age and operation site did not have an influence on the survival rate. There was statistically significant differences for the implants which placed in less than 4 or 5 rom residual bone height, the survival rate was 60%, 81.4% respectively (p<0.05). There was no statistically significant difference of implants survival rate ac- cording to approach technique. The survival rate for 100% autogenous bone grafts was lower with respect to composite grafts containing autogenous bone and 100% substitutes. The survival rate for hydroxyapatite-coated implants was statistically significant lower than other textured group (p<0.05). Conclusion: Residual bone height, surface texture and graft materials have an influence on the survival rate. To use autogenous bone as a part of a composite bone replacement, implant texture which leads to more favorable implant-bone interface were necessary. To determine residual bone height for initial implant stability was important.

• Journal of Periodontal and Implant Science
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• 제50권6호
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• pp.418-434
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• 2020

Purpose: The purpose of the present study was to evaluate the effect of silica-calcium phosphate composite (SCPC) granules on bone regeneration in extraction sockets. Methods: Ten patients were selected for a split-model study. In each patient, bone healing in SCPC-grafted and control ungrafted sockets was analyzed through clinical, radiographic, histomorphometric, and immunohistochemical assessments 6 months postoperatively. Results: A radiographic assessment using cone-beam computed tomography showed minimal ridge dimension changes in SCPC-grafted sockets, with 0.39 mm and 1.79 mm decreases in height and width, respectively. Core bone biopsy samples were obtained 6 months post-extraction during implant placement and analyzed. The average percent areas occupied by mature bone, woven bone, and remnant particles in the SCPC-grafted sockets were 41.3%±12%, 20.1%±9.5%, and 5.3%±4.4%, respectively. The percent areas of mature bone and woven bone formed in the control ungrafted sockets at the same time point were 31%±14% and 24.1%±9.4%, respectively. Histochemical and immunohistochemical analyses showed dense mineralized bundles of type I collagen with high osteopontin expression intensity in the grafted sockets. The newly formed bone was well vascularized, with numerous active osteoblasts, Haversian systems, and osteocytes indicating maturation. In contrast, the new bone in the control ungrafted sockets was immature, rich in type III collagen, and had a low osteocyte density. Conclusions: The resorption of SCPC granules in 6 months was coordinated with better new bone formation than was observed in untreated sockets. SCPC is a resorbable bone graft material that enhances bone formation and maturation through its stimulatory effect on bone cell function.

• 멤브레인
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• 제31권4호
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• pp.268-274
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• 2021

지구 온난화 이슈에서 가장 고질적인 문제 중 하나는 온실가스의 배출이다. 다양한 온실 가스 중 가장 높은 비중을 차지하는 이산화탄소(CO₂)는 이를 분리하기 위해 연구자들이 지속적으로 연구를 진행해오고 있다. 이러한 관점에서 본 연구에서는 이산화탄소 기체를 분리하기 위해 poly(vinyl alcohol) (PVA) 기반 공중합체를 제조하여 기체 분리막에 활용했다. 공중합체는 자유 라디칼 중합법을 활용했으며, 곁사슬을 위한 단량체로 아크릴산(acrylic acid)를 사용하여 PVA-g-PAA(VAA) 그래프트 공중합체를 제조했다. 본 공중합체를 이산화탄소 기체분리막에 적용한 사례는 최초이며, 폴리설폰 지지체에 복합막 형태로 제조했다. 공중합체 합성 결과는 FT-IR을 통해, 합성한 공중합체 의 거동은 TEM과 DSC, TGA를 통해 분석하였다. AA 그래프팅을 통해 공중합체는 나노 구조를 형성하며, PVA의 결정화도를 급격하게 감소시켜 이산화탄소의 용해도를 증가시켰고, 이는 이산화탄소 기체 분리 성능을 향상시켰다. 이를 통해 이산화탄소 분리막 분야에 용액-확산 및 그래프팅 방법이라는 새로운 접근법을 제시하였다.

• 멤브레인
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• 제14권4호
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• pp.298-303
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• 2004

PTMSP/PDMS-PEI 복합막을 제조하고, 막의 특성을 FT-IR, $^1$H-NMR, DSC, TGA, GPC, SEM을 사용하여 조사하였다. 제조된 PTMSP/PDMS copolymer의 수평균분자량((equation omitted))은 501,516이었고, 중량평균분자량((equation omitted))은 675,560이었다. 제조된 고분자 복합막에 의한 $H_2$/$N_2$ 혼합기체분리는 $25^{\circ}C$에서 압력의 변화에 따라 조사하였다. PTMSP/PDMS-PEI 복합막들의 수소에 대한 분리인자($\alpha$, $\beta$, (equation omitted)) 값은 투과셀의 압력이 증가하면 증가하였다. PTMSP/PDMS-PEI 복합막의 수소에 대한 $\alpha$, $\beta$, (equation omitted) 값은 $\Delta$P 345.55 kPa와 $25^{\circ}C$에서 각각 21.50, 49.14, 1.84이었다.

• Journal of Chest Surgery
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• 제46권4호
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• pp.265-273
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• 2013

Background: The safety and efficacy of arterial composite grafts for total arterial revascularization have been demonstrated. The saphenous vein (SV) is a widely used graft because of its accessibility, sufficient length, and ease of manipulation. Our aim was to compare mid-term outcomes of saphenous vein Y-grafts with radial artery Y-grafts joined by anastomosis to the left internal thoracic artery. Materials and Methods: Records of off-pump coronary artery bypass grafting with composite Y-grafts based on the left internal thoracic artery technique in 552 patients were analyzed retrospectively. After propensity score matching, 79 radial arterial (RA) composite grafts (RA group) and 79 saphenous vein composite grafts (SV group) were compared. The duration of mean follow-up was $24.6{\pm}14.6$ months (range, 1 to 55 months). Results: There were no differences in surgical mortality, all-cause mortality, or morbidity among the groups. Rates of 4-year survival were 91.7% and 96.3% in the RA and SV groups, respectively (p=0.519). The coronary reintervention-free survival rate and freedom from major adverse cardiovascular or cerebrovascular events were similar in the two groups (p=0.685, p=0.564). Conclusion: Construction of composite Y-grafts using the radial artery or saphenous vein showed similar mid-term results. Long-term follow-up and randomized trials will be needed to confirm our present conclusions.

• Archives of Reconstructive Microsurgery
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• 제10권1호
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• pp.60-63
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• 2001

The reconstruction of the suborbital area followed by resection of skin cancer has been used many methods including skin graft, local flaps, free flaps, and skin expansion. The radial forearm free flap has become a workhorse flap in this area because of its lack of bulk, ease of dissection, malleability, and hairlessness. When the suborbital defect especially including full-thickness defect of lower lid was reconstructed with many free flaps, the ectropion and the deformity of medial and lateral canthal area were common problems encountered as late complication due to gravitational descent. To improve the final aesthetic result in patients with suborbital defect, the radial forearm free flap was elevated as a composite radial forearm - palmaris longus free flap, in which the vascularized palmaris longus london was included and anchored to the periorbital bone with $mitek^{(R)}$ as sling, to suspend the flap against gravity and inferior descent, and thereby creating a more natural cheek contour. Two clinical cases were presented as an example of this procedure. Postoperative results emphasize the importance of suspension sling with palmaris longus tendon using $mitek^{(R)}$ in reconstruction of the suborbital defect with radial forearm free flap.

• KIEAE Journal
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• 제10권1호
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• pp.97-107
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• 2010

Although aspiration towards quality of life and holistic health has been growing faster in our modern society and the affordance of health in built environment has been more acknowledged, there has been hardly any development on built environment planning and design theory that can be comfortably and confidently used in creating built environment to promote holistic health. Thereby, this study sets out to experimently formulate a composite theory that explains the relationship between health and built environment. The main methodology of this study is literature review and analysis. Theories that have been applied in other similar fields were chosen to be analyzed by health related perspectives and graft those theories onto holistic health viewpoints to compose a comprehensive theory. Selected theories that were considered useful to be analyzed were Lawton's Environment Press Theory, Carp & Carp's Complementary & Congruence Theory, Valins' Activity-based Design Criteria Theory, Atchley's Continuity Theory, Murtha & Lee's User Benefit Criteria Theory, and Alexander's Pattern Language Theory. Characteristics of these theories were compared by their abstractness and concreteness, and the range of application, and analyzed by a holistic health perspective. Then, these theories were comprehensively structuralized and synthesized as a built environment for health theory. This study has its significance in providing a base to develop healthy built environment research further as it introduced a conceptual framework which explains spatial elements in the health functionality point of view.

• Journal of Chest Surgery
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• 제36권7호
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• pp.510-513
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• 2003

우심실 저형성 환자에서 심실중격결손과 대동맥판막 폐쇄부전 및 대동맥판륜 확장증이 동반된 경우는 매우 드물다. 저자들은 우심실 저형성 환자에서 심실중격결손, 대동맥판막 폐쇄부전 및 대동맥판륜 확장증이 동반되어 composite graft를 이용한 근부치환술을 시행한 증례를 보고한다. 환자는 19세 남자로 심장초음파 및 심도자 검사에서 직경 2 cm크기의 막성 심실중격결손과 심한 대동맥판막 폐쇄부전증, 그리고 대동맥판륜 확장증이 동반되어 있었으며 우심실은 bipartite 형태로 심한 저형성을 보였고 Qp/Qs는 1.2였다. 수술소견 상 우관상 및 비관상 판첨 변연부 길이의 현저한 확장, 판첨의 비후와 수축, 그리고 교련부의 융합 및 석회화가 있었다. 수술은 대동맥근부를 통해 자가 심낭 패취를 이용한 심실중격결손 폐쇄술 및 composite graft를 이용한 button Bentall 술식과 우심실 유출로 부위의 비후된 근육을 절제하여 주었다. 환자는 수술 직후 일시적인 심폐기 이탈의 어려움이 있었으며 술 후 14일째 특별한 합병증 없이 퇴원하였다.

• Journal of Periodontal and Implant Science
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• 제32권4호
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• pp.753-767
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• 2002

The purpose of this study was to evaluate histologically the effect of LiF-maleic acid added calcium aluminate(LM-CA) bone cement & CA-PMMA composite bone cement on the healing of calvarial defect in Sprague-Dawley rats. The critical size defects were surgically produced in the calvarial bone using the 8mm trephine bur. The rats were divided in three groups : In the control group, nothing was applied into the defect of each rat. LM-CA bone cement was implanted in the experimental group 1 and CA-PMMA composite bone cement was implanted in the experimental group 2. Rats were sacrificed at 2, 8 weeks after surgical procedure. The specimens were examined by histologic analysis, especially about the bone-cement interface and the response of surrounding tissue. The results are as follows; 1. In the control group, inflammatory infiltration was observed at 2 weeks. At 8 weeks, periosteum and duramater were continuously joined together in the defect area. But the center of defect area was filled up with the loose connective tissue. 2. In the experimental group 1, the bonding between implanted bone cement and the existing bone was seen, which more increased in 8 weeks than 2 weeks. Inflammatory infiltration and the dispersion of implanted bone cement particles were seen in both 2 weeks and 8 weeks. 3. In the experimental group 2, implanted bone itself had a dimensional stability and no bonding between implanted bone cement and the existing bone was seen in both 2 weeks and 8 weeks. Implanted bone cement was encapsulated by fibrous connective tissue. In addition, inflammatory infiltration was seen around implanted bone cement. On the basis of these results, when LM-CA bone cement or CA-PMMA composite bone cement was implanted in rat calvarial defect, LM-CA bone cement can be used as a bioactive bone graft material due to ability of bonding to the existing bone and CA-PMMA can be used as a graft material for augmentation of bone-volume due to dimensional stability.