• Korean Membrane Journal
• /
• 제9권1호
• /
• pp.57-63
• /
• 2007

Amphiphilic graft copolymer from poly(vinylidene fluoride) (PVDF) was synthesized using atom transfer radical polymerization (ATRP) for composite nanofiltration membranes. Direct initiation of the secondary fluorinated site of PVDF facilitates grafting of tert-butyl methacrylate (tBMA). Amphiphilic PVDF-g-PMAA graft copolymer with a 51:49 wt ratio was obtained by hydrolyzing poly(tert-butyl methacrylate) (PtBMA) to poly(methacrylic acid) (PMAA). Wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) confirmed the decrease of crystallinity of PVDF upon graft copolymerization. Composite nanofiltration membranes were prepared from PVDF-g-PMAA as a top layer coated onto PVDF ultrafiltration (UF) support membrane. The morphology and hydrophilicity of membranes were characterized using scanning electron microscopy (SEM) and contact angle measurement. The rejections of composite membranes were 80.2% for $Na_2SO_4$ and 28.4% for NaCl, and the solution flux were 9.5 and $14.5\;L/m^2\;h$ at 1.0 MPa pressure.

• Archives of Plastic Surgery
• /
• 제34권3호
• /
• pp.377-382
• /
• 2007

Purpose: Hook nail deformity is caused by inadequately supported nail bed due to loss of distal phalanx or lack of soft tissue, resulting in a claw-like nail form. A composite graft from the foot bencath the nail bed gives adequate restoration of tip pulp. Methods: From September of 1999 to March of 2004, six patients were treated for hook nail deformity and monitored for long term follow up. Donor sites were the lateral side of the big toe or instep area of the foot. We examined cosmetic appearance and nail hooking and sensory test. The curved nail was measured by the picture of before and after surgery. Results: In all cases, composite grafts were well taken, and hook nail deformities were corrected. The curved nail of the 4 patients after surgery were improved to average $28.7^{\circ}$ from average $55.2^{\circ}$ before surgery. The static two point discrimination average was 6.5mm and the moving two point discrimination average was 5.8mm in the sensory test. Conclusion: Composite graft taken from foot supports the nail bed with the tissue closely resembling the fingertip tissue, making it possible for anatomical and histological rebuilding of fingertip.

• Elastomers and Composites
• /
• 제58권3호
• /
• pp.128-135
• /
• 2023

To improve the adhesive strength of natural rubber (NR) for a seismic isolation damper, citraconic acid-g-NR (CCA-g-NR) was synthesized via the melt grafting of citraconic acid (CCA) onto NR using an azobisisnomerobutyronitrile (AIBN) initiator. Subsequently, the influence of CCA and AIBN concentrations on the graft ratio G/R (%) and graft efficiency G/E (%) of the CCA-g-NR was investigated. The optimum CCA and AIBN concentrations required to achieve the desired G/R (3.49%) and G/E (49.8%) were found to be 7 phr and 0.13 phr, respectively. Additionally, we studied the influence of CCA-g-NR concentration on the mechanical properties (tensile strength, elongation at break, and modulus at 300%), adhesive strength, and cure characteristics of the rubber compound in the seismic isolation damper. As the concentration of CCA-g-NR increased, the elongation at break and adhesive strength of the compound increased, whereas its tensile strength and modulus at 300% decreased. Moreover, as the concentration increased, the maximum torque decreased and the scorch time was delayed to obtain an optimal vulcanization time.

• Journal of Chest Surgery
• /
• 제42권3호
• /
• pp.324-330
• /
• 2009

배경: 관상동맥우회술에서 흔히 사용되는 복재정맥 도관을 상행대동맥에 문합하여 사용한 경우의 개통률은 유경 내흉동맥 도관에 비해 낮은 것으로 알려져 있다. 본 연구에서는 심폐바이패스를 사용하지 않는 관상동맥우회술에서 복재정맥을 좌내흉동맥에 연결하여 복합도관으로 사용하였을 때의 조기 임상 결과 및 문합부 개통률을 동맥도관을 복합도관으로 사용한 경우와 비교하고자 하였다. 대상 및 방법: 2006년 9월부터 2008년 10월 사이에 심폐바이패스를 사용하지 않는 관상동맥우회술을 받은 419명의 환자 중에서 좌내흉동맥을 유경이식편으로 하여 복합도관을 조성했던 295명(70.4%)을 대상으로, 복합도관의 조성에 복재정맥을 사용했던 군(I군, n=71)과 동맥도관 만을 사용했던 군(II군, n=224)으로 나누어 임상결과를 비교하였다. 모든 환자에서 수술 후 초기($1.6{\pm}1.6$일)에 관상동맥조영술을 시행하여 문합부 개통률을 분석하였다. 결과: 원위부 문합수는 I군이 $3.5{\pm}1.0$개, II군이 $3.1{\pm}0.8$개였다(p=.002). 수술관련 사망률은 0.7% (2/295)였으며, 수술 후 합병증으로 심방세동(n=73, 24.7%), 수술 전후 심근경색(n=6, 2.0%), 급성신부전(n=6, 2.0%), 출혈로 인한 재수술(n=5, 1.7%), 뇌졸중(n=3, 1.0%), 종격동염(n=1, 0.3%)등이 있었으며, 복재정맥의 사용 여부와는 무관하였다. 술 후 관상동맥조영술에서 I군의 복재정맥 개통률은 96.9% (126/130)였으며, II군의 복합 동맥도관 개통률은98.8% (479/485)였다(p=.231). 결론: 내흉동맥을 유경 이식편으로 하는 복합도관을 이용하여 심폐바이패스를 사용하지 않는 관상동맥우회 술에서, 복재정맥을 복합도관으로 사용하였을 경우 조기 임상 성적 및 문합부 개통률은 동맥도관과 유사하여, 동맥도관 부족 시 복합도관으로서 복재정맥의 사용 가능성을 제시하였으며, 향후 장기 추적관찰 연구가 필요하다.

• Archives of Plastic Surgery
• /
• 제39권3호
• /
• pp.190-197
• /
• 2012

Background : This article presents long-term outcomes after correcting secondary bilateral cleft lip nasal deformities using a refined reverse-U incision and V-Y plasty or in combination with a composite graft in order to elongate the short columella. Methods : A total of forty-six patients underwent surgery between September 1996 and December 2008. The age of the patients ranged from 3 to 19 years of age. A bilateral reverse-U incision and V-Y plasty were used in 24 patients. A composite graft from the helical root was combined with a bilateral reverse-U incision in the 22 patients who possessed a severely shortened columella. The follow-up period ranged between 2 and 10 years. Results : A total of 32 patients out of 46 were evaluated postoperatively. The average columella length was significantly improved from an average of 3.7 mm preoperatively to 8.5 mm postoperatively. The average ratio of the columella height to the alar base width was 0.18 preoperatively and 0.29 postoperatively. The postoperative basal and lateral views revealed a better shape of the nostrils and columella. The elongated columella, combined with a composite graft, presented good maintenance of the corrected position with no growth disturbance. A composite graft showed color mismatching in several patients. Twenty-six patients demonstrated no alar-columella web deformity and satisfactory symmetry of the nostrils. Four patients experienced a drooping and overhanging of the corrected alar-columella web. Conclusions : A bilateral reverse-U incision with V-Y plasty or in combination with a composite graft was effective in correcting secondary bilateral cleft lip nasal deformity.

• Archives of Reconstructive Microsurgery
• /
• 제16권2호
• /
• pp.57-62
• /
• 2007

Non-vascularized free composite graft is one of the simple and effective reconstructive options, but its clinical use has been limited due to questionable survival rate. Early vascularization is essential for graft survival and is mainly carried out via recipient bed or repaired sites. This study was designed to investigate the effect of the lateral marginal approximations on the survival of the free composite flap using a model of skin-subcutaneous composite graft in rats. Thirty 1.5 ${\times}$ 1.5 $cm^2$ sized square shape composite flaps were elevated freely and reposed in place immediately on the dorsum of five Sprague-Dawley rats, and divided into five groups of six flaps. In all groups, graft bed was isolated with silastic sheet. In the group I, all sides of flap were repaired with blockage of silastic sheet insertion. Three, two, and one sides of flap were treated with same method in the group II, III, and IV respectively. Other sides of flaps were repaired without blockage, so all sides of flap were repaired in the group V. At 14 days later, the survived rate of each flap was evaluated according to the numbers of the repair sites. Histological examination was done for the evaluation of new vessel development quantitatively. Overall survived rates were increased with the number of repaired sites, but the group V only showed increased survival rate up to more than fifty percentile of the flap size with a significant difference statistically. New vessels were also increased in proportion with the number of repaired sites, and the repair site more than two had significant effect on the increased number of new vessels. In conclusion, at least more than three-fourth of flap circumference should be repaired in order to increase flap survival effectively under the condition of bed isolation.

• Journal of Chest Surgery
• /
• 제27권2호
• /
• pp.153-156
• /
• 1994

Bentall`s operation for repair of annuloaortic ectasia has been associated with postoperative bleeding and with false aneurysm of the anastomotic site between the coronary orifice and composite graft.Among 5 cases, 2 cases have been operated direct anastomosis between coronary artery and vascular graft.Remained 3 cases have been operated with doughnutlike Teflon felt buttress.The technique of sandwiching the freed button of aortic wall bearing the coronary artery ostium between an outer Teflon felt doughnutlike buttress and the inner composite graft provides a leak-proof anastomosis.We experienced one case reoperation for bleeding at coronary anastomotic site above method.

• Journal of Chest Surgery
• /
• 제26권6호
• /
• pp.457-462
• /
• 1993

We retrospectively studied 34 patients who underwent operations of ascending aortic aneurysm and aortic valve replacement from August 1979 to July 1992 at the Yonsei Cardiovascular Center. Eight patients underwent supracoroanry non-composite graft replacement and separate aortic valve replacement[group I]. Twenty six patients underwent valved composite graft replacement with reimplantation of coronary arteries[group II]. Two cases in group II died within 1 month after the operation. Among the 32 survivors 28 patients have been followed up for an average of 59 months ranging from 1 months to 159 months. During the follow up periods, a pseudoaneurysm around the ascending aorta and a newly developed dissecting aneurysm in remaining aorta were noted in group II. There were 6 late deaths: 2 cases in group I and 4 cases in group II. Three cases among the 6 late deaths have stigmata of Marfan`s syndrome[1 cases in group I and 2 case in group II]. There was no statistically significant difference in actuarial survival rates between group I and group II[p > 0.05]. This study suggests that non-composite supracoronary graft interposition with separate aortic valve replacement is a safe surgical technique in patients who have normal aortic annulus and normal position of coronary ostia. However in degenerative disease such as cystic medial necrosis, composite graft replacement is recommended because this procedure eliminates entire abnormal tissue.But it seems to be important that the suture technique and strict follow-up in patients with diseased aortic wall.

• Journal of Chest Surgery
• /
• 제37권10호
• /
• pp.839-844
• /
• 2004

배경 및 목적: 속가슴동맥 편과 유리 노동맥 편의 Y-복합이식편은 관상동맥우회 술에 많이 이용된다. 이 연구의 목적은 속가슴동맥 편의 혈류를 증가시킬 수 있는 방법을 찾고 Y-복합이식편의 혈류역학을 알고자 함이다. 대상 및 방법: 관상동맥우회 술을 받은 15예에서 속가슴동맥 편을 두 가지 방법으로 처치하여 속가슴동맥 혈류량을 측정하였다. 7예에서는 혈관 외부에만 파파베린 액을 처치하였고 8예에서는 혈관 내로 파파베린 액을 주입하였다. 다른 18예에서는 속가슴동맥 편과 유리 노동맥 편으로 Y-복합이식편을 만들어 사용하였고 그 자유 혈류량과 두 분지의 혈류 변화를 조사하였다. 결과: 속가슴동맥 편의 혈관 내로 파파베린을 주사한 경우는 혈관외부에 파파베린을 처치한 경우보다 약 2배의 자유혈류량을 얻을 수 있었다(47.7$\pm$9.6 mL/min와 100.8$\pm$26.3 mL/min, p<0.001). Y-복합이식편의 양측을 다 연 상태에서 총 자유혈류량은 속가슴동맥 측만을 열었을 때나 노동맥 측만을 열었을 경우보다 훨씬 많았다(173.3$\pm$45.3 mL/min와 121.1$\pm$34.3 mL/min 혹은 117.5$\pm$42.8 mL/min, 각각 p<0.001). Y-복합이식편의 양 분지를 다 연 경우 양측의 혈류량은 차이가 없었다(85.4$\pm$27.8 mL/min와 87.9$\pm$42.4 mL/min, p=0.772). Y-복합이식편에서 한 측의 혈류량은 다른 측을 열 때보다 막을 때 훨씬 많았다. 결론: 속가슴동맥 편의 혈관 내에 파파베린 액을 주입하는 방법은 자유혈류량을 올릴 수 있는 매우 효과적인 방법이다. 속가슴동맥 편과 유리 노동맥 편의 Y-복합이식편은 속가슴동맥의 단독이식편보다 더 많은 자유혈류량을 보이며, Y-복합이식편의 한 측의 혈류량은 다른 측의 혈류량의 변화에 따라 변할 수 있다.

• Archives of Plastic Surgery
• /
• 제44권5호
• /
• pp.370-377
• /
• 2017

Background Composite grafts are frequently used for facial reconstruction. However, the unpredictability of the results and difficulties with large defects are disadvantages. Adipose-derived stem cells (ADSCs) express several cytokines, and increase the survival of random flaps and fat grafts owing to their angiogenic potential. Methods This study investigated composite graft survival after ADSC injection. Circular chondrocutaneous composite tissues, 2 cm in diameter, from 15 New Zealand white rabbits were used. Thirty ears were randomly divided into 3 groups. In the experimental groups (1 and 2), ADSCs were subcutaneously injected 7 days and immediately before the operation, respectively. Similarly, phosphate-buffered saline was injected in the control group just before surgery in the same manner as in group 2. In all groups, chondrocutaneous composite tissue was elevated, rotated 90 degrees, and repaired in its original position. Skin flow was assessed using laser Doppler 1, 3, 6, 9, and 12 days after surgery. At 1 and 12 days after surgery, the viable area was assessed using digital photography; the rabbits were euthanized, and immunohistochemical staining for CD31 was performed to assess neovascularization. Results The survival of composite grafts increased significantly with the injection of ADSCs (P<0.05). ADSC injection significantly improved neovascularization based on anti-CD31 immunohistochemical analysis and vascular endothelial growth factor expression (P<0.05) in both group 1 and group 2 compared to the control group. No statistically significant differences in graft survival, anti-CD31 neovascularization, or microcirculation were found between groups 1 and 2. Conclusions Treatment with ADSCs improved the composite graft survival, as confirmed by the survival area and histological evaluation. The differences according to the injection timing were not significant.