미끄럼운동 시 TiN 코팅에 형성되는 산화막이 마찰 및 마멸 특성에 미치는 영향

조정우(Chung-Woo Cho),이영제(Young-Ze Lee) 한국트라이볼로지학회 2002 한국윤활학회지(윤활학회지) Vol.18 No.4

내분비교란물질의 독성 및 미생물에 의한 생물학적 분해

조정우(Chung Woo Cho),박선호(Sun Ho Park) 계명대학교 낙동강환경원 1998 環境科學論集 Vol.3 No.1

금호강 수돗물의 돌연변이원성

조정우,김수철,박주영,박갑성 ( Chung Woo Cho,Soo Chul Kim,Joo Young Park,Kap Song Park ) 한국물환경학회 1994 한국물환경학회지 Vol.10 No.4

Ames Mutagenicity assay has been used to evaluate mutagenicity of Kumho river water and chlorinated drinking water. Kumho river water showed negative mutagenic responses both far strains TA98 and TA 100, however the mutagenic ratios increased with. the volume of water samples. Generally, chlorinated drinking water showed positive mutagenic responses. Mutagenic responses were clear in the acid drinking water samples, which suggested that acid chlorinated by-products may induce mutagenicity in the Kumho drinking water samples.

익상편수술시 결막소판술과 자가결막이식술의 재발률 비교

조정우,정소향,서경률,김응권,Jung-Woo Cho,M,D,Soh-Hyang Chung,M,D,Kyoung-Yul Seo,M,D,Eung-Kweon Kim,M,D 대한안과학회 2005 대한안과학회지 Vol.46 No.9

Purpose: To compare postoperative recurrence rates between conjunctival autotransplant ation and the conjunctival mini-flap technique in pterygium surgery and to identify factors associated with postoperative recurrence. Methods: In a retrospective survey of patients who underwent pterygium surgery between March, 2001 and February, 2004 at Severance Hospital, 49 eyes with pterygium removed by the conjunctival mini-flap technique and 41 eyes that underwent pterygium removal surgery by the conjunctival autotransplantation technique were studied. Results: During the mean follow-up period of 8.79±3.9 months, recurrence of pterygium was observed in 3 of 49 eyes (7.1%) that received the conjunctival mini-flap technique. There were 9 recurrent cases out of 41 eyes (21.9%) that were treated by the conjunctival autotransplantation technique. There was no statistical significance between recurrence rate and age, sex, or previous operation in either of the respective surgical techniques. Conclusions: This study showed that the conjunctival mini-flap technique has a lower recurrence rate than the conjunctival autotransplantation technique. We also found that the conjunctival mini-flap technique is an effective and safe technique that does not generally cause serious complications.

소규모 정수처리 공정수의 돌연변이원성

조정우,박갑성 ( Chung Woo Cho,Kap Song Park ) 한국물환경학회 1993 한국물환경학회지 Vol.9 No.1

Ames mutagenicity assay has been used to evaluate a small scale water treatment process which consists of bed filtration, sand filtration and chlorination process. Raw river water, bed filtered and sand filtered water demonstrated a negative mutagenic response with the Ames assay. Chlorinated water, however, induced mutagenicity suggesting chlorination produces increased levels of mutagenic activity in the treated water. Tester strains TA98 and TA100 which contain R-factor plasmid was found to be sensitive for the raw river water and chlorinated drinking water while TA1537 and TA1538 strains were not sensitivity for the studied waters.

양안 라식 수술 후에 발생한 단안의 급성 각막수종의 임상증례

정소향,조정우,김응권,So-Hyang Chung,Jung-Woo Cho,Eung-Kweon Kim,Ph,D 대한안과학회 2005 대한안과학회지 Vol.46 No.7

Purpose: To report a case of a patient who underwent penetrating keratoplasty due to acute hydrops six years after undergoing a bilateral LASIK procedure. Methods: A 19-year old male patient with -2.75 diopter myopia received a bilateral LASIK operation at a local clinic. Forty-seven months later, -2.00 cyl axis 130o astigmatism was induced in his left eye and additional surgery was performed to correct the LASIK-induced astigmatism. The patient was referred to our hospital 16 months after the secondary operation due to reduced visual acuity in his left eye. He was diagnosed with keratectasia and acute hydrops, and penetrating keratoplasty was performed. Results: The retrospective analysis of the corneal topography prior to the LASIK surgery revealed that the inferior minus superior(I-S) value was 1.25 in the right eye and 1.3 in the left eye. At the time of the first evaluation at out hospital, a slit lamp examination showed an approximate 8x7.5mm sized area filled with aqueous humor between the corneal flap and residual stroma, and Descemet`s membrane rupture was observed. Furthermore, the histopathological section of the patient`s cornea confirmed keratocytes with myxoid degeneration and edematous change. Conclusions: In young patient, particularly those with suspicious asymptomatic keratoconus, LASIK and further enhancement surgery afterwards should be considered and approached in a cautious and deliberate manner.

전기화학적 분석을 통해 산출된 코팅 결함율이 트라이볼로지적 특성에 미치는 영향 평가

김우중(Woo-Jung Kim),안승호(Seung-Ho Ahn),김호건(Ho-Gun Kim),김정구(Jung-Gu Kim),조정우(Chung-Woo Cho),이영제(Young-Ze Lee) 한국트라이볼로지학회 2004 한국윤활학회지(윤활학회지) Vol.20 No.6

Many of the current development in surface modification engineering are focused on multilayered coatings, which have the potential to improve the tribological properties. Four different multilayered coatings were deposited on AISI D2 steel in this study. The prepared samples are designed as WC-Ti_(0.6)Al_(0.4)N, WCTi_(0.53)Al_(0.47)N, WC-Ti_(0.5)Al_(0.5)N and WC-Ti_(0.43)Al_(0.57)N. The multilayered coatings were investigated with respect to coating surface and cross-sectional morphology, roughness, adhesion, hardness, porosity and tribological behaviors. Especially, wear tests of four multilayered coatings were performed by using a ball-on-disc configuration with a linear sliding speed of 0.017 m/sec and a normal load of 5.38 N load. The tests were carried out at room temperature in air by employing AISI 52100 steel ball (H_R = 66) having a diameter of 10 ㎜. The surface morphology, and topography of the wear scars of samples and balls have been determined by using scanning electron spectroscopy (SEM). Also, wear mechanism was determined by using SEM coupled with energy-dispersive spectroscopy (EDS). Results have showed an improved wear resistance of the WC- Ti_(1-x)AlxN coatings with increasing of Al (aluminum) concentration.

전기화학적 분석을 통해 산출된 코팅 결함율이 트라이볼로지적 특성에 미치는 영향 평가

김우중(Woo-Jung Kim),안승호(Seung-Ho Ahn),김호건(Ho-Gun Kim),김정구(Jung-Gu Kim),조정우(Chung-Woo Cho),이영제(Young-Ze Lee) 한국트라이볼로지학회 2004 한국트라이볼로지학회 학술대회 Vol.38 No.-

Recently, many of the current development in surface modification engineering are focused on multilayered coatings. Multilayered coatings have the potential to improve the tribological properties. Four different multilayered coatings were deposited on AISI D2 steel. The prepared samples are designed as WC-Ti0.6Al0.4N, WC-Ti0.6Al0.4N, WC-Ti0.53Al0.47N and WC-Ti0.43Al0.57N. The multilayered coatings were investigated with respect to coating surface and cross-sectional morphology, roughness, adhesion, hardness, porosity and tribological behavior. Especially, wear tests of four multilayered coatings were performed by using a ball-on-disc configuration with a linear sliding speed of 0.017 m/sec, 5.38 N load. The tests were carried out at room temperature in air by employing AISI 52100 steel ball (HR = 66) having a diameter of 10 ㎜. The surface morphology, and topography of the wear scars of samples and balls have been determined by using scanning electron spectroscopy (SEM). Also, wear mechanism was determined by using SEM coupled with EDS. Results have showed an improved wear resistance of the WC-Ti1-xAlxN coatings with increasing of Al concentration.

회분식 발효에 의한 HTS-융합 B30-homoserine 인슐린 전구체의 생산

김종식 ( Jong Shik Kim ),조정우 ( Chung Woo Cho ) 한국공업화학회 2003 공업화학 Vol.14 No.4

회분식 발효 공정을 이용하여 HTS-융합 B^30-homoserine insulin precursor의 생산에 관한 연구를 수행하였다. HTS-융합 B^30-homoserine insulin precursor를 발효 생산하는데 이용할 수 있는 적절한 배지를 선정하기 위해 5 L 발효조 상에서 실험을 수행하였다. TS 배지의 경우 OD_600 값이 10.16으로 가장 높았으며, YT-G 배지, HD 배지, LB 배지에서는 각각 OD_600 값이 6.74, 5.02, 3.82로 TS 배지에서 배양한 경우보다 훨씬 낮게 나타났다. 성장기별 재조합 단백질 생산 양상을 고찰한 결과 TS 배지에서 배양액의 농도가 OD_600 값으로 3.7~4.0인 중기 대수성장기에서 0.5 mM의 IPTG로 유도한 다음 2 h 더 배양한 후의 재조합 단백질 생산량이 38.95 mg/L-h로 성장기별 총 단백질량에 대한 재조합 단백질량의 비와 생산성에서 가장 높게 나타났다. Ni^2+-affnity column chromatography로 분리 ·정제한 재조합 단백질은 9.12 mg/L이었고, 분리·정제 수율은 발현된 재조합 단백질량의 17.5%이었다. For a novel anti-diabetic drug raw material, B^30-homoserine insulin precursor in a batch fermentation was studied to obtain a maximal production of HTS-fused B^30-homoserine insulin precursor in the recombinant Escherichia coli cells. The cultivation medium for an optimal growth was found to be TS. The maximal production of insulin precursor was achieved when the gene expression was induced by 0.5 mM IPTG at the middle logarithmic growth phase, especially when the cell density reached to 3.7 ~4.0 of OD_600. The highest productivity of insulin precursor was obtained as much as 38.95 mg/L-h, after the gene induction for 2 h, the total insulin protein occupied more than 12.8% of total protein of the recombinant E. coli cells. The HTS-fused B^30-homoserine insulin precursor was recovered from a batch culture through the processes of cell harvest, collection of insoluble fraction after sonication, and purification by nickel affinity column chromatography. The finally isolated insulin precursor was 9.12 mg/L with a recovery yield of 17.5% of the expressed gene product.

융합 단백질을 이용한 B30-homoserine 인슐린 전구체의 발현과 분리,정제

김종식 ( Jong Shik Kim ),조정우 ( Chung Woo Cho ) 한국공업화학회 2003 공업화학 Vol.14 No.4

HTS-융합 B^30-homoserine insulin precursor 유전자 발현 및 분리·정제 연구를 수행하였다. 플라스크상에서 재조합 단백질 유전자 발현을 위한 최적 조건은 밤새 배양한 종배양액 1% (v/v)를 새로운 배지에 주입한 후 2 h 동안 배양하고 그 배양액 1% (v/v)를 새로운 배지에 주입한 후 다시 3 h 더 배양한 다음 0.05 mM 또는 0.1 mM의 IPTG를 주입하고 다시 4 h 더 배양된 경우로 나타났다. Ni^2+-affinity column chromatography에서 1X elute buffer로 유출된 분획을 SDS-PAGE로 분석한 결과 9 kDa 크기의 단일 band를 나타내는 재조합 단백질이 분리·정제되었음을 확인할 수 있었다. 아미노산 분석에서 lysine을 제외한 나머지 아미노산들의 계산치와 측정치의 유사정도는 86%이었다. For a novel anti-diabetic drug raw material, B^30-homoserine insulin precursor in the recombinant Escherichia coli cells was examined in a flask for gene expression and purification process. The optimal culture condition for gene expression was at inoculation of 1% (v/v) pre-culture grown for 2 h to a fresh LB medium; the supplementation of 0.05~0.1 mM of IPTG for gene induction after subsequent cultivation for 3 h and further culture for 4 h. In In Ni^2+-affinity column chromatography, single band of 9 kDa was appeared on SDS-PAGE for the purification of HTS-fused B^30-homoserine insulin precursor. The measured and calculated values of amino acid residues were approximately 86%, with exception to lysine.