용탄단조법에 의한 AC4A/SiCw 복합재료 제조에 관한 연구 (3) -기계적 특성-

문경철,이준희,윤의박 ( Kyung Cheol Moon,Jun Hee Lee,Eui Pak Yoon ) 한국열처리공학회 1994 熱處理工學會誌 Vol.7 No.3

This was studied about mechanical characteristic of AC4A/SiCw 10-30% reinforced composites. Tensile strength of pressed base metal(base metal) with SiCw preform was higher than without pressed base metal(AC4A) If SiCw whisker volume fraction was increased, tensile strength at room temperature was increased. And tensile strength of SiCw 30% was about 35㎏/㎟. Tensile strength of SiCw 30% 400℃ at same time aging was the most excellence, about 40㎏/㎟ The fracture energy value of composite material at three point bending test was higher than AC4A. Dislocation at matrix of composite material was evenly distributed. But dislocation around whisker of composite material was more existed than matrix. The reasom was thought of pile-up around whisker.

The Prognostic Implications of the Histologic Subtype and the Expression of Phosphorylated ERK 1/2 in Papillary Renal Cell Carcinoma

문경철,김보성,김동일,강태훈,신은 대한병리학회 2008 Journal of Pathology and Translational Medicine Vol.42 No.4

Background : The authors of this study wanted to confirm the prognostic implication of the histologic subtype; further, we wanted to explore the expression of phosphorylated extracellular signal-regulated kinase 1/2 (pERK) in papillary renal cell carcinoma (PRCC) and determine its clinicopathologic and prognostic significance. Methods : A total of 45 patients who underwent nephrectomy for PRCC were enrolled in this study. The hematoxylin and eosin slides were reviewed and pERK immunohistochemistry was performed. Results : Type 2 PRCC was significantly correlated with a larger tumor size (p=0.030), a higher nuclear grade (p<0.001), a more advanced tumor stage (p=0.041) and more frequent distant metastasis(p=0.019). The tumors were pERK-low (0 and 1+) in 30 cases (66.7%) and pERK-high (2+) in 15 cases (33.3%). The pERK-high PRCC was significantly associated with a smaller tumor size (p=0.001) and an earlier tumor stage (p=0.004). On the univariate analysis, the histologic subtype, the TNM stage and the pERK status were significantly associated with progression- free survival (PFS). Multivariate analysis showed that the histologic subtype (hazard ratio 22.81, p=0.042) and the TNM stage (hazard ratio 23.48, p=0.009) were independent prognostic factors for PFS. Conclusions : Type 2 PRCC, together with the TNM stage, was identified as one of independent poor prognostic factors for PFS. The pERK status was a prognostic factor for PFS on the univariate analysis, but not on the multivariate analysis.

The Prognostic Implications of Cystic Change in Clear Cell Renal Cell Carcinoma

문경철,박혜성,정은정,명재경 대한병리학회 2010 Journal of Pathology and Translational Medicine Vol.44 No.2

Background : Cystic renal cell carcinoma has been reported to have a good prognosis. However, previous studies included cases of multilocular cystic renal cell carcinoma, which has an excellent prognosis, and renal cell carcinoma with cystic necrosis, which has an adverse prognosis. Therefore, we analyzed the prognostic influence of cystic change in clear cell renal cell carcinoma after excluding those morphological features. Methods : We identified 225 patients with clear cell renal cell carcinoma who underwent nephrectomy between 2001 and 2003. The clinicopathologic features were compared with clinical outcomes. Results : Cystic change in clear cell renal cell carcinoma (n = 66) was significantly associated with younger patient age (< 55), smaller tumor size (≤ 4 cm), lower pT stage (pT1, T2), M0 stage at initial diagnosis, lower tumor, node, and metastasis stage (I, II), and lower nuclear grade (1, 2). Patients with cystic change in clear cell renal cell carcinoma had significantly longer cancer-specific (p = 0.015) and progression-free survival (p = 0.004) than those without cystic change, by univariate analysis. Multivariate analysis revealed that cystic change significantly decreased the risk of cancer progression (risk ratio, 0.27; 95% confidence interval, 0.11 to 0.69). Conclusions : In patients with clear cell renal cell carcinoma, cystic change is a good independent predictor for survival.

IgA 신병증, 미만성 반월체 사구체신염, 미소변화형 신증에서 접착분자의 발현

문경철,박소연,김활웅,이현순 대한병리학회 2000 Journal of Pathology and Translational Medicine Vol.34 No.5

용탕단조법에 의한 AC4A / SiCw 복합재료의 인장특성과 미세조직

문경철,이준희 ( Kyung Cheol Moon,Jun Hee Lee ) 한국주조공학회 1994 한국주조공학회지 Vol.14 No.2

N/A Macro and micro structures by optical microscope(OM), scanning electro microscope(SEM) and transmission electro microscope(TEM) of AC4A/SiCw 10-30v/o reinforced composites were observed. Fracture mode of AC4A alloy was appeared to be plastic. But fracture mode of composites were appeared to be almost elastic. And that was occured very well with increasing of SiC whisker volume fraction. Mechanical characteristics of preformed SiC whisker reinforced composites by squeeze casting technique were more affected by squeezing pressure than temperature of molten metal. Distribution of dislocations at matrix of composites was uniform. But the number of dislocations around whisker of composites was much more than in matrix. These diffraction pattern were [011] direction for both matrix and around whisker.

Transglutaminase 2 Expression and Its Prognostic Significance in Clear Cell Renal Cell Carcinoma

문경철,박민지,백해운,이예영,이철,박정환,김활웅 대한병리학회 2015 Journal of Pathology and Translational Medicine Vol.49 No.1

Background: A few recent studies have demonstrated a possible role of transglutaminase 2 (TG2) in tumorigenesis or progression of renal cell carcinoma (RCC). The aim of this study was to examine TG2 expression and its clinicopathologic significance in a large number of human clear cell RCCs (CCRCCs). Methods: We analyzed 638 CCRCC patients who underwent partial or radical nephrectomy between 1995 and 2005. The expression of TG2 was determined by immunohistochemistry and categorized into four groups, according to staining intensity: negative (0), mild (1+), moderate (2+), and strong (3+). Results: TG2 staining intensity was negative in 8.5% of CCRCC (n=54), 1+ in 32.6% (n=208), 2+ in 50.5% (n=322), and 3+ in 8.5% (n=54). Strong TG2 expression was correlated with high Fuhrman nuclear grade (p=.011), high T category (p=.049), metastasis (p=.043) and male sex (p<.001) but not with N category.The survival analysis showed a significant association between strong TG2 expression and worse overall and cancer-specific survival (p=.027 and p=.010, respectively). On multivariate analysis, strong TG2 expression was a marginally significant prognostic indicator for Fuhrman nuclear grade and TNM staging (p=.054). Conclusions: Our study is the first to demonstrate the clinicopathologic significance of TG2 expression in a large number of human CCRCC samples. Strong TG2 expression was associated with high nuclear grade and poor prognosis.

Choice of recipient vessels in muscle-sparing transverse rectus abdominis myocutaneous flap breast reconstruction: A comparative study

문경철,이재민,Si-Ook Baek,Seo-Yoon Jang,Eul-Sik Yoon,이병일,Seung-Ha Park 대한성형외과학회 2019 Archives of Plastic Surgery Vol.46 No.2

Background Thoracodorsal vessels (TDVs) and internal mammary vessels (IMVs) have both been widely employed as recipient vessels for use in free muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flaps. However, whether TDVs or IMVs are preferable as recipient vessels for autologous breast reconstruction with a free MS-TRAM flap remains controversial. The purpose of this study was to compare the clinical outcomes when TDVs were used as recipient vessels to those obtained when IMVs were used as recipient vessels for autologous breast reconstruction with a free MS-TRAM flap. Methods A retrospective matched-cohort study was performed. We retrospectively reviewed data collected from patients who underwent a free MS-TRAM flap for autologous breast reconstructions after mastectomy between March 2003 and June 2013. After a one-to-one matching using age, 100 autologous breast reconstructions were selected in this study. Of the 100 breast reconstructions, 50 flaps were anastomosed to TDVs and 50 to IMVs. Patient demographics and clinical outcomes including operation time, length of hospital stay, postoperative complications, and aesthetic score were compared between the two groups. Results No statistically significant differences were found between the two groups in patient demographics and clinical outcomes, including the complication rates and aesthetic scores. There were no major complications such as total or partial flap loss in either group. Conclusions The results of our study demonstrate that both TDVs and IMVs were safe and efficient as recipient vessels in terms of the complication rates and aesthetic outcomes.

Modified Double-Eyelid Blepharoplasty Using the Single-Knot Continuous Buried Non-Incisional Technique

문경철,윤을식,Jun-Mun Lee 대한성형외과학회 2013 Archives of Plastic Surgery Vol.40 No.4

Background Buried non-incisional double-eyelid blepharoplasty is a popular aesthetic procedure. Although various modified continuous suture techniques have been used to create a more natural appearance and to reduce downtime, complications such as loosening of the double fold, asymmetry, and foreign body reactions have been observed. Methods This study included 250 patients who underwent double-eyelid blepharoplasty between March 1997 and November 2012 using a modified single-knot continuous buried non-incisional technique. With 4 stab incisions in the upper eyelids, one of two needles loaded with double-armed 7-0 nylon was passed in one direction alternately through the dermis and the conjunctiva, while the other needle was passed subconjunctivally in the opposite direction. Both ends of the sutures were knotted within a lateral stab incision of the upper eyelids and were buried in the orbicularis oculi muscle. Results Most patients displayed satisfactory aesthetic results, and no significant complications occurred. There was no obvious regression of the double fold; however, 3 patients required reoperation to correct loosening of the fold on one side during the follow-up period. One patient presented with the suture knot subcutaneously, and the knot was removed in the clinic. Conclusions The modified single-knot continuous buried non-incisional technique is a simple and less time-consuming method for a durable double fold and provides satisfactory aesthetic results.

용탕단조법에 의한 AC4A/$SiC_w$복합재교 제조에 관한 연구(ll)-가압력 및 시효특성-

문경철,이춘희,Mun, Gyeong-Cheol,Lee, Chun-Hui 한국재료학회 1993 한국재료학회지 Vol.3 No.6

자동차용 부품재 및 일반산업용 재료로 사용되고 있는 AC4A Al합금에 $SiC_{w}$ preform을 용탕단조법으로 강화시킨 복합재료의 시효 경화능은 SiC/aub w/30%> 10%> 20%의 순이며, 이는 $100^{\circ}C$-$400^{\circ}C$까지의 등시시효에서도 같은 결과를 나타낸다. 복합재의 T6처리재가 AC4A I/M재 보다도 시효경화능이 크고 절대값이 높았으며 $SiC_{w}$체적분율 증가에 따라 초기경화 현상을 나타내었다. 가압력에 의한 강화효과는 미시효때와 같이 가압력 75MPa일때 가장 좋았으며, $SiC_{w}$는 30%> 10%>20%순이었다. 가압력이 낮을경우 가입과 동시에 휘스커는 파단되지 않고 원래의 형상을 유지하거나 기지금속과 wetting으로 일부 변형된 다음 가압이 진행되면서 이부부의 응력 집중으로 wetting부가 파단하게 되어 가압력을 이기지 못하고 파단하게 되어 휘스커 모양도 다각형이거나 구형에 가깝게 되며 가압이 진행됨에따라 재차 파단되므로써 길이도 짧게 된다. 한편 가압력 75 MPa일 경우 휘스커의 형상은 일부 변형된 것과 잘게 파손된 것이 고르게 공존하고 있어 강화효과가 가장 우수한 것으로 사료된다. This was studied about aging characteristic of AC4A/$SiC_{w}$ 10-30v/o reinforced composite. Aging hardenability was decreased $SiC_{w}$ 30% > 10% > 20%. Aging hardening of T6 treatmented composite was higher absolute value than AC4A I/M material. And this results indicated initial hardening phenomenon according to increase $SiC_{w}$ volume fraction. Reinforced effect by pressure was the same effect as before aging treatment and the best condition pressure at 75MPa. Similar to reinforced effect according to $SiC_{w}$ volume fraction was 30 % > 10 % > 20 %. In case of pressure is low, whisker is not break the same time press with base metal after wetting. After it is wetting with base metal, a part transformed or wetting part break and whisker maintain original shape or a part transformed on the otherhand, in case of pressure is high, whisker is break in same time it was not against pressure and whisker's shape is near a polygon or spherical shape.

計裝化 샬피 시험법 에 의한 알루미늄 합금 용접부 의 동적파괴 인성

문경철,강락원,이준희 대한용접접합학회 1985 대한용접·접합학회지 Vol.3 No.2

The dynamic fracture toughness, fracture characteristics, impact tension and tensile properties of Al-Mg-Si T5 alloy and Al-Zn-Mg T6 alloy respectively welded with filler metal of Alcan 4043 were investigated. The dynamic fracture toughness values were obtained rapidly and simply for the specimen of small size by using instrumented Chirpy impact testing machine. the testing temperatures of the specimen were a range of room temperature and-196.deg. C. The results obtained in this experiment are summarized as follows. With decreasing the testing temperatures, dynamic tensile stress and fracture load were increased, on the other hand the deflection and impact value showed decreasing tendency in order of base metal>HAZ>weld. Changes of total absorbed energy were more influenced by the crack propagation energy than the crack initiation energy. At the low temperatures, the unstable rapid fracture representing the crack propagation appeared for the specimens of Charpy press side notched in Al-Zn-Mg alloy, but it was difficult to obtain the unstable rapid fracture in Al-Mg-Si alloy. Because of the development of plastic zone at the notch root, it was difficult to obtain thevalid $K_{1d}$ value in Al-Mg-Si alloy. Therefore the fatigue cracked specimens were effective in both Al-Mg-Si and Al-Zn-Mg alloys. With decreasing the impact testing temperatures, specimens underwent a transition from dimple-type transgranular fracture to lamella surface-type intergranular fracture because of the precipitate at the grain boundaries, impurities and crystal structure of the precipitates.s.