Fe-Ni-C 합금의 Ausforming처리에 의한 기계적성질의 변화

백승남,강조원 조선대학교 동력자원연구소 1987 動力資源硏究所誌 Vol.9 No.1

The ausformed martensite obtained from austenite with various deformation degrees in Fe-30% Ni-0.25% C alloy was transformed to reversed austenite at 500℃ by cyclic reverse martensitic transformation. The effects of prior deformation and number of cyclic transformation on the microstructure, mechanical properties of reversed austenite were investigated. The results obtained are summarized as follows : 1) Prior deformation degrees applied below A_d point raises A_f point.A_f points of ausformed martensites in this alloy are from 475 C to 486 C with prior deformation degrees. 2) The strength of reversed austenite is higher than that of original austenite without prior deformation. This is considered to be due to the higher dislocation density and grain size refinement. 3) The yield strength of reversed austenite below 25% prior deformation is higher than that of deformed austenite, but above 25% prior deformation, the yield strength of the reversed austenite is lower than that of the deformed austenite. 4) The strength of reversed austenite is more increased with the number of cyclic transformation, especially it is principally strengthened at the first cyclic transformation and the strengthening effect is more remarkable in yield strength than in ultimate tensile strength.

주요우울증에 대한 Milnacipran의 효과 및 안정성 : Fluoxetine과의 비교

이민수,함병주,기백석,김정범,연병길,오강섭,오병훈,이철,정한용,지익성,최병무,백인호 大韓神經精神醫學會 2004 신경정신의학 Vol.43 No.4

Objectives : This 6-week, open label randomized, multicenter study was conducted to evaluate the antidepressant effect and safety of milnacipran and fluoxetine in patients with major depression. Methods : The study was done in patients with major depression diagnosed by DSM-IV who score ≥17 in 17 items Hamilton Rating Scale for Depression (17-item HAM-D) and score ≥25 in Montgomery and Asberg Depression Rating Scale (MADRS). A total of 87 patients were randomized to milnacipran group and fluoxetine group. In cases of the patients taking other antidepressants, 6 weeks of each medication was administered after 7 days of drug excretion period. The evaluation was done using 17 item HAM-D, MADRS, Clinical Global Impression Scale (CGI), and COVI scale after baseline, 1 week, 2 weeks, 4 weeks, and 6 weeks. The side effects that had occurred during the period of our study were put in records by developed/disappeared time, severities, incidences, managements and results. Results : A total of 87 patients were enrolled. 70 (mitnacipran group 39 ; fluoxetine group 31) of them were included for the 6 weeks of research and 17 of them dropped out with in the first week, not due to adverse reactions or deficiency of effects. Total 17 item HAM-D scores, total points of MADRS, and CGI showed significant decrease after 1 week in each treatment group and continued decrease after 2 weeks and 4, 6 weeks. But there was no difference between milnacipran group and fluoxetine group in the antidepressant effect. There were no significant changes in vital sign, CBC, chemistry, and EKG in each treatment group. The commonly reported side elfects of minlacipran were nausea (25.0%), headache (10.7%), vomiting (7.1%),constipation (7.1%), dizziness (7.1%) and those of fluoxetne were GI trouble (11.1%), diarrhea (11.1%), insomnia (11.1%),agitation (5.6%), and dizziness (5.6%). Conclusion : Milnacipran was effective for the improvement of depressive symptoms and was well tolerated and safe in patients with depression.

Helicobacter pylori 편모 유전자의 클로닝 및 염기서열 분석

이광호,이우곤,조명제,도영미,백승철,강경희,박필성,이상룡 경상대학교 유전공학연구소 1993 遺傳工學硏究所報 Vol.12 No.-

A λgt11 expression libary of H. pylori DNA in E. coli Y1090 was screened with flagellin-specific rabbit antiserum for molecular cloning of the flagellin gene of H. pylori. A positive clone, λHPF4, was obtained and the recombinant antigen expressed from λHPF4 was a fusion protein with the molecular weight of 168kd. Sequence analysis of antigen-encoding DNA showed that an open reading frame composed of 1,536 nucleotides encodes a polypepride with a oredicted molecular size of 54kd. This open reading frame did not show the homology with flaA gene encoding 56kd protein of H. pylori and was confirmed as a unique sequence through homoligy searching. Therefore, the cloned antigen is supposed to be the carboxy-terminal region of the other flagellin protein of H. pylori, flaB, with the molecular weight of 58kd.

Sample Size Calculations for the Development of Biosimilar Products Based on Binary Endpoints

Kang, Seung-Ho,Jung, Ji-Yong,Baik, Seon-Hye The Korean Statistical Society 2015 Communications for statistical applications and me Vol.22 No.4

It is important not to overcalculate sample sizes for clinical trials due to economic, ethical, and scientific reasons. Kang and Kim (2014) investigated the accuracy of a well-known sample size calculation formula based on the approximate power for continuous endpoints in equivalence trials, which has been widely used for Development of Biosimilar Products. They concluded that this formula is overly conservative and that sample size should be calculated based on an exact power. This paper extends these results to binary endpoints for three popular metrics: the risk difference, the log of the relative risk, and the log of the odds ratio. We conclude that the sample size formulae based on the approximate power for binary endpoints in equivalence trials are overly conservative. In many cases, sample sizes to achieve 80% power based on approximate powers have 90% exact power. We propose that sample size should be computed numerically based on the exact power.

Risk factor analysis of postoperative complications after robotic rectal cancer surgery.

Kang, Jeonghyun,Min, Byung Soh,Park, Yoon Ah,Hur, Hyuk,Baik, Seung Hyuk,Kim, Nam Kyu,Sohn, Seung Kook,Lee, Kang Young Springer International 2011 World journal of surgery Vol.35 No.11

<P>The robotic system has been adopted as the new modality for minimally invasive surgery for rectal cancer. However, analysis of risk factors for complications after robotic rectal cancer surgery (RRS) has been limited. This study aimed to identify the risk factors for complications after RRS.</P>

직장에 발생한 위장관 간질종양 7예

백승혁(Seung Hyuk Baik),김남규(Nam Kyu Kim),이중호(Chung Ho Lee),이강영(Kang Young Lee),손승국(Seung Kook Sohn),조장환(Chang Hwan Cho),김호근(Ho Geun Kim),표홍렬(Hong Ryull Pyo),라선영(Sun Young Rha),정현철(Hyun Chul Chung) 대한외과학회 2005 Annals of Surgical Treatment and Research(ASRT) Vol.68 No.2

슬관절 전치환술의 운동학

강승백 ( Seung Baik Kang ) 대한슬관절학회 2010 대한슬관절학회지 Vol.22 No.4

최근의 기술의 발전에 의해, 슬관절 인공관절 치환술에서 삽입물의 마모를 최소화하고 관절운동범위를 증가시키며, 하지의 정렬과 안정성을 확보하기 위해 정상 슬관절의 굴곡 운동을 재현하는 것이 가장 중요한 목표가 되어가고 있다. 실제로 전치환술 이후의 보행 분석과 방사선 투시를 이용한 분석에 의하면 슬관절 전치환술의 운동 패턴은 여러 인자에 의해 복잡하게 영향을 받는 것을 알 수 있다. 시상면에서, 정상 슬관절의 굴곡 시 대퇴골은 경골 고평부에서 후방으로 구름과 동시에 또한 미끄러지는 운동을 하는 것은 잘 알려진 사실이며 이런 슬관절의 운동 양식은 대퇴과와 경골 고평부의 모양뿐만 아니라 후방십자인대의 기능과 긴밀하게 연관이 있다. 이 두 가지 인자에 의해 슬관절 굴곡 시에는 중간 운동 범위에서 내측에 회전 축을 가지는 경골의 내회전을 일으키게 되며 120˚ 이상의 고도 굴곡 시에는 양측 대퇴과 모두 후방으로 전위되게 된다. 슬관절 전치환술시에도 굴곡시에 마찬가지로 대퇴골의 후방전위는 나타나며 캠-포스트를 가지는 후방 십자인대 대치형 슬관절 전치환술에서 이런 대퇴골의 후방전위는 더 일정하게 나타나게 된다. 또한 슬관절 전치환술 후 대퇴 후과의 오프셋의 회복은 고도 굴곡 시 생기는 대퇴골과 경골의 충돌을 막게 되어 좀 더 증가된 관절운동 범위를 가지게 된다. In the current age of technological advances, reproducing the knee kinematics for minimizing wear and increasing the range of motion, together with obtaining proper alignment and stability, have become the major goals of total joint replacement. The kinetics of total knee arthroplasty (TKA) have a complex influence on its performance, and differing abnormal patterns have been shown after TKA by using gait analysis, fluoroscopy and radiostereometry. In the sagittal plane, it is now understood that the femoral condyles roll and glide simultaneously on the tibial plateau during flexion. The kinematics of the knee and the shape of the condyles and the tibial plateau are closely interrelated with the functions of the cruciate ligaments. The kinematics result from the combined actions of the surface geometry of the joint and the soft tissues attached to it. To a variable extent in the mid-range, these factors cause tibial internal rotation to occur with flexion around a medial axis. From 120_ to full flexion, both condyles roll back onto the posterior horn so that the tibio-femoral joint subluxes. In TKA, it has been demonstrated that substituting a cam-and-post mechanism for the PCL (posterior cruciate ligament) shows consistent posterior femoral rollback during flexion. Restoration of the posterior condylar offset is important since it allows a greater degree of flexion before impingement occurs.

당뇨병이 있는 환자에게 시행한 인공 슬관절 전치환술의 결과

강승백(Seung-Baik Kang),조영재(Young-Jae Cho),윤강섭(Kang-Sup Yoon),이지호(Ji Ho Lee),조현철(HyunChul Jo),이재협(Jae-Hyup Lee),한혁수(Hyuk Soo Han) 대한정형외과학회 2007 대한정형외과학회지 Vol.42 No.6

목적: 당뇨병을 앓고 있는 환자에게 시행한 인공 슬관절 전치환술(TKA)의 임상결과를 알아보고자 하였다. 대상 및 방법: 1996년 3월부터 2001년 10월까지 본원에서 슬관절의 골관절염으로 TKA를 시행 받은 373명 601예 중 당뇨가 있었던 45명(74예)를 대상군으로 하였다. 대상군은 모두 제2형 당뇨에 이환되어 있었다. 평균추시 기간은 49개월(6-108개월)이었으며, 평균연령은 68.6세(54-83세)였다. 대상군과 대조군의 HSS 점수 및 KSS 점수, 방사선적 해리소견, 표재성 창상문제 및 심부 감염 여부, 내과적 합병증발생 여부를 평가, 비교하였고, 당뇨군에서 수술 전과 추시 시에 혈장 당화혈색소 수치를 검사했다. 결과: 최종 추시 시 KSS 임상점수와 통증 점수는 당뇨군이 비당뇨군에 비해 높았으며(각각 p=0.040, 0.039), HSS 점수와 기능점수는 비당뇨군이 높았다(각각 p=0.021, 0.016). 표재성 창상 합병증은 당뇨군에서 6예(8.1%), 비당뇨군에서 8예(2.4%) 관찰되어 당뇨군에서 유의하게 많았다(p=0.032). 심부 감염은 당뇨군에서 2예(2.7%), 비당뇨군에서 3예(0.9%) 관찰되었고 두 군 간에 유의한 차이는 없었다(p=0.224). 대상군 중 표재성 창상 합병증과 심부 감염이 발생한 환자들의 당화혈색소수치가 감염증이 발생할 당시 평균 8.4% (7.9-8.7%)였고, 이는 대상군 중 감염이 발생하지 않은 환자들의 평균치인 5.7% (4.0-8.1%)에 비해 유의하게 높았다(p=0.033). 결론: 당뇨병을 동반한 골관절염 환자에서 TKA의 임상 결과는 비당뇨병 환자와 비교하여 큰 차이가 없었지만, 감염 및 창상 합병증에 대하여 철저한 주의가 요구된다. 당화혈색소수치는 TKA와 연관된 창상문제 및 감염예방 을 위한 지표로써 가치가 있다. Purpose: To analyze the results of total knee arthroplasty (TKA) in patients with diabetes mellitus (DM). Materials and Methods: Between 1996 and 2001, 601 TKAs in 373 patients were performed by a single surgeon. From this series, 45 patients (74 knees) were diagnosed as type Il DM and osteoarthritis of the knee. The mean follow-up was 49 months (6-108 months), and the mean age was 68.6 years (54-83 years). The clinical outcome of the diabetic and non diabetic group was compared using the Hospital for special surgery score (HSS) and the Knee society clinical and radiological scoring system. The radiological loosening and perioperative complications were evaluated. The plasma Hemoglobin A1c (HbA1c) level of the diabetes patients was examined pre and postoperatively. Results: The knee and pain scores were higher in the diabetes group postoperatively (p=0.040, p=0.039, respectively), whereas the HSS scores and overall function scores were lower in the diabetes group postoperatively (p=0.021, p=0.016, respectively). The rate of superficial wound problems was greater in the diabetes group (8.1 % versus 2.4%, p=0.032). However the incidence of a deep infection was similar in the diabetic and non diabetic group (2.7% versus 0.9%). The mean HbA1c level was significantly higher in the diabetic patients with a superficial and deep infection than in the remaining diabetic patients (p=0.033). Conclusion: The HbA1c level might be a valuable predictor of superficial wound complications and deep infection. Although the clinical results were similar in the diabetes and non diabetes groups, special precautions should be taken for diabetic patients undergoing TKA to minimize complications.

미세포말형 대퇴 스템에서 Hydroxyapatite와 Tricalcium-Phosphate의 효과

강승백(Seung Baik Kang),이지호(Ji Ho Lee),박진수(Jin Soo Park),윤강섭(Kang Sup Yoon) 대한정형외과학회 1998 대한정형외과학회지 Vol.33 No.3

척수이형성 환아에서 족부변형의 수술적 치료

강승백(Seung Baik Kang),최인호(In Ho Choi),정진엽(Chin Youb Chung),이덕용(Duk Yong Lee) 대한정형외과학회 1994 대한정형외과학회지 Vol.29 No.3