Robotic Surgery in the Orthopedic Field

Of the many factors that affect the clinical outcomes of orthopedic surgery, the surgical procedure is the most important. Robotics have been developed to perform the surgical procedures more accurately and consistently. Robotic surgical procedures in the orthopedic field were developed 20 years ago. Some designs of surgical robots have disappeared due to practical problems and complications, and an another design of surgical robots is emerging. To date, the use of robot surgery in arthroplasty is still controversial in terms of the clinical outcomes, practicality, and cost-effectiveness, even though it has been reported to be effective in the alignment and positioning of components in the field of artificial joints. Early robotic surgery was based mainly on active robot surgery according to the scheduled operation without the intervention of the operator. Recently the semi-active system of robotic surgery has been introduced. In a semi-active system, the robot constrains the surgeon to a haptic boundary defined by the computer based on the 3-dimensional imaging preoperative plan, and the operator can change the preoperative plan through real-time feedback during operation.ope

Case report. Acinar cell carcinoma with fatty change arising from the pancreas

Acinar cell carcinoma of the pancreas is a rare malignant tumour developing from acinar cells, accounting for approximately 1% of pancreatic exocrine tumours. We experienced a case of an acinar cell carcinoma with fatty change. To the best of our knowledge, this is the first case report of an acinar cell carcinoma with fatty change in the clinical literature.ope

Difference in Bone Mineral Density Change at the Lateral Femoral Cortices according to Administration of Different Bisphosphonate Agents.

BACKGROUND: To retrospectively assess whether the response of subtrochanteric lateral cortex (STLC) is different according to the bisphosphonate agents in terms of bone mineral density (BMD) change. METHODS: A total of 149 subjects, who had 2- to 4-year interval follow-up of BMD using dual energy X-ray absorptiometry (DXA), were included in this retrospective study divided into following 3 groups: control group (no consumption of any anti-osteoporotic drugs, n=38), alendronate group (naïve alendronate users, n=48), risedronate group (naïve risedronate users, n=63). BMD was measured at the STLC and subtrochanteric medial cortex (STMC) in each patient by drawing rectangular ROIs at the bone cortices. The percent change of BMD at the STLC were compared between the aforementioned 3 groups by using analysis of covariance model to control five independent variables of age, body mass index, percent change of STMC, hip axis length, time interval between DXA examinations. RESULTS: The least square mean values±standard deviation of the percent change of BMD in the control, alendronate, and risedronate groups were 1.46±1.50, 2.23±1.26, and 6.96±1.11, respectively. The risedronate group showed significantly higher change of BMD percentage compared with the control (adjusted P=0.012) or alendronate (adjusted P=0.016) groups. CONCLUSIONS: The percent change of BMD at the STLC in the risedronate user group was greater than the alendronate and control groups. The implication of these changes needs to be further verified.ope

Atypical traumatic anterior shoulder instability with excessive joint laxity: recurrent shoulder subluxation without a history of dislocation

BACKGROUND: No previously published studies have examined recurrent traumatic incomplete events in patients with excessive joint laxity. The purpose of this study is to investigate outcomes after arthroscopic stabilization for recurrent traumatic shoulder subluxation in patients with excessive joint laxity but no history of dislocation. METHODS: This study included 23 patients with glenoid bone defects less than 20% who underwent arthroscopic stabilization of recurrent shoulder subluxation and were available for at least 2 years follow-up. Outcomes were assessed with the subjective shoulder value (SSV), University of California Los Angeles (UCLA) shoulder score, Rowe score, and sports/recreation activity level. RESULTS: Postoperatively, overall functional scores improved significantly (p < 0.001), compared to preoperative scores: SSV improved from 49.1 to 90.4; Rowe score improved from 36.7 to 90.2; and UCLA shoulder score improved from 26.3 to 32.5. Patient satisfaction rate was 87% (20/23 patients). Sports/recreation activity level (return to premorbid activity level; grade I = 100% to grade IV = less than 70%) was grade I in 7 patients, grade II in 11, grade III in 3, grade IV in 2. The incidence of any glenoid bone defect was 61% (14/23 patients), and the mean glenoid bone defect size was 8%; among these 14 patients, 8 (35%) exhibited 15-20% glenoid bone defects. Instability reoccurred in 2 patients (9%) who had 15-20% glenoid bone defect. CONCLUSION: Despite excessive joint laxity, overall functional outcomes after arthroscopic stabilization of recurrent shoulder subluxation were satisfactory. However, arthroscopic Bankart repair may not be reliable in patients with excessive joint laxity plus a glenoid bone defect size of more than approximately 15%.ope

Epithelial Wound Healing after Cataract Surgery Comparing Two Different Topical Fluoroquinolones

PURPOSE: To compare the epithelial wound healing response of two preservative-free fluoroquinolones, moxifloxacin and levofloxacin, in patients who underwent cataract surgery. MATERIALS AND METHODS: In this prospective, evaluator-masked, randomized clinical trial, 59 eyes of 50 patients who underwent cataract surgery were enrolled. Patients were randomized to receive moxifloxacin 0.5% (n=32 eyes) or levofloxacin 0.5% (n=27 eyes). All patients instilled moxifloxacin or levofloxain four times daily for 1 week prior to surgery and 2 weeks after surgery. The epithelial wound healing status in the corneal incision site was scanned with a raster scan mode of fourier-domain optical coherence tomography (FD-OCT). The number of eyes showing epithelial defect images and average number of corneal epithelial defect cuts per eye were compared between groups. All patients were evaluated on postoperative days 1, 2, 3, and 10. RESULTS: On postoperative days 1, 2, and 3, the number of eyes showing epithelial defects in FD-OCT was not statistically different (all p>0.05). The average number of corneal epithelial defect cuts was also not statistically different between the two groups (all p>0.05). No eyes showed epithelial defects on postoperative day 10 in either group. CONCLUSION: There were no differences on epithelial wound healing comparing these two different fluoroquinolones at the incision site of cataract surgery.ope

Matroid and Rainbow Matching

학위논문 (석사)-- 서울대학교 대학원 : 자연과학대학 수리과학부, 2019. 2. 국웅.변이 색칠된 그래프가 주어져 있을 때 모두 다른 색을 가지는 부합(matching)을 rainbow matching이라고 한다. n개의 색으로 변이 색칠된 완전 이분 그래프의 rainbow matching의 최대 크기에 대한 추측이 Ryser, Brualdi, Stein에 의해 제기되었다. 최대 크기의 하한(lower bound)에 대해서 어디까지 연구되었는지 알아보고, 군(group)의 Cayley table으로 추측을 제한한 문제(Hall-Paige)와 2009년의 결과(Wilcox-Bray-Evan)에 대해서 알아보았다. 그 결과에 대한 응용으로 group으로 문제를 제한한 경우에서 rainbow matching의 최대 크기에 대한 하한을 얻었고, dihedral group에 대해서 Ryser-Brualdi-Stein 추측이 참인 것을 확인해 보았다. 또한 기본적인 Matroid이론과 Ryser-Brualdi 추측의 Matroid로의 확장에 대한 연구에 대해서 알아보았다.A rainbow matching of an edge-colored graph is a matching which edges have all distinct colors. It is natural to ask about the maximum size of rainbow matching of a given edge-colored graph. This paper gives a survey on the problem, especially on the complete bipartite graphs $K_{n,n}$ which is equivalent to the Ryser-Brualdi-Stein conjecture on the Latin squares. An introduction to matroid theory and generalized versions of Ryser-Brualdi-Stein conjecture on the matroids are surveyed. The Ryser conjecture on the Cayley tables of groups is called the Hall-Paige conjecture which was solved by Wilcox, Bray, and Evan in 2009. We give applications of the theorem. One of the application gives a lower bound for the maximum size of a rainbow matching when the bipartite graph is induced by a group. Also, we showed that there is an $n-1$ partial transversal for the Cayley table of a dihedral group, which means that the Brualdi-Stein conjecture on the dihedral groups is true.Contents 1 Introduction 4 2 Latin Squares and Transversals 5 2.1 Ryser-Brualdi-Stein Conjecture . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 Lower bounds for the maximum size of rainbow matchings . . . . . . . . . . 6 3 Cayley tables of groups 7 3.1 Complete mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2 Finite abelian group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3 Hall-Paige conjecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.4 First application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.5 Second application : A lower bound . . . . . . . . . . . . . . . . . . . . . . . 13 4 On the Dihedral Groups 14 5 Rainbow matchings in the Complete Graphs 16 6 Matroid 18 6.1 Matroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 6.2 Alternative denitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 6.3 Dual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 6.4 Deletion and Contraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 6.5 Direct sum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 6.6 Excluded minor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 6.7 Excluded minors of graphic matroid . . . . . . . . . . . . . . . . . . . . . . . 26 6.8 Matroid representation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 6.9 Robertson-Seymour Theorem and Matroid . . . . . . . . . . . . . . . . . . . 28 6.10 Transversal matroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 7 Matroid and Generalized Conjectures 29 7.1 Matroidal Latin Square . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 7.2 Intersection of two matroids . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Maste

In vitro evaluation of 10 different stents using 16-slice versus 64-slice Multi-Detector Computed Tomography (MDC

의학과/석사[한글] 목적 16채널과 64채널 컴퓨터 단층 관상동맥 혈관촬영술 (16-slice and 64-slice multi-detector computed tomography, 이하 MDCT)을 이용하여 관상동맥용 혈관 스텐트의 영상화를 분석하고자 하였다. 재료 및 방법 국내에서 사용되는 10 종류의 스텐트를 혈관 모형에 설치 후 16채널과 64채널 MDCT에서 촬영하였다. 스텐트의 영상화를 위해 B30f 커넬과 B46f 커넬을 이용하여 영상을 재구성 하였다. 영상은 인위적 내경감소율, 내경내의 감쇠 (intraluminal attenuation), 그리고 스텐트에 의한 인공물을 분석하였다. 결과 인위적 내경 감소율은 64채널 MDCT에서 B46f 커넬을 이용하는 경우 통계학적으로 유의하게 작았다. 내경내의 감쇠는 통계학적으로 16채널 및 64채널 MDCT 사이에서 의미 있는 차이를 보이지 않았으나, B46f 커넬에서 두 기종 모두 의미 있는 내경내 감쇠의 차이를 보였다. 인공물은 재질에 따른 분석 시 코발트-크롬 합금이 스테인래스 재질을 사용한 스텐트보다 더 감소하였다. 인공물은 스텐트 스트러트 두께와 중간 정도의 상관관계를 보였다. 결론 관상동맥용 혈관 스텐트의 영상화에 있어서 인위적 내경 감소율은 64채널 MDCT가 16채널 MDCT보다 우위에 있다. 특히 B46f 커넬을 사용한 경우 B30f 커넬에 비해 스텐트 내경의 영상화에 더 좋은 결과를 얻을 수 있다. 또한 코발트-크롬 합금을 이용하거나 스텐트 스트러트가 작을수록 스텐트의 영상화에 더 많은 이점이 있다 [영문]Purpose The aim of this study was to assess the visualization of different coronary artery stents using 16- and 64-slice multi-detector computed tomography (MDCT) coronary angiography. Materials and Methods Ten different coronary artery stents used in Korea were placed in a vascular phantom and examined with 16- and 64-slice MDCT. For image reconstruction, B30f and B46f kernels for coronary artery stent visualization were used. Images were analyzed regarding artificial luminal narrowing (ALN), intraluminal attenuation, and artifacts by the stent. Results 64-slice MDCT with B46 kernel had the lowest ALNs than other protocols. The difference of attenuation values in the stented segment of the tube was significantly lower for using B46f kernel regardless of 16-slice and 64-slice MDCT. Stents made of cobalt-chromium alloy were significantly lower in artifact scores than stainless steel 316L. There was a positive correlation for artifact scores between the stent and stent strut thickness. Conclusion Use of the 64-slice MDCT with a B46f kernel is superior to the 16-slice MDCT with a B46f kernel or a B30f kernel for coronary artery stent visualization. Especially, use of the stents made of cobalt-chromium alloy with thin strut thickness results in superior visualization of stent lumen compared to the stents made of stainless steel 316Lope

이눌린 분해효소와 식물독소 톡소플라빈 분해효소의 3차 구조 규명과 생화학적 기능 연구

학위논문 (박사)-- 서울대학교 대학원 : 농생명공학부, 2014. 2. 이상기.Inulin fructotransferase (IFTase), a member of glycoside hydrolase family 91, catalyzes a depolymerization of β-2,1-fructans inulin by successively removing the terminal difructosaccharide units as cyclic anhydrides via intramolecular fructosyl transfer. The crystal structures of IFTase and its substrate-bound complex reveal that IFTase is a trimeric enzyme, and each monomer folds into a right-handed parallel β-helix. Despite variation in the number and conformation of its β-strands, the IFTase β-helix has a structure that is largely reminiscent of other β-helix structures, but is unprecedented in that trimerization is a prerequisite for catalytic activity and the active site is located at the monomer-monomer interface. Results from crystallographic studies and site-directed mutagenesis provide a structural basis for the exolytic-type activity of IFTase, and a functional resemblance to inverting-type glycosyltransferases. Pathogenic bacteria synthesize and secrete toxic low molecular weight compounds as virulence factors, which play essential roles in the pathogenicity of bacteria in various hosts. Therefore, these chemicals are targets for antivirulence strategies. The phytopathogen Burkholderia glumae BGR1 produces a phytotoxin, toxoflavin, which is the key factor in bacterial wilting of crop plants. Recently, toxoflavin-degrading enzyme (TxDE) was identified from Paenibacillus polymyxa JH2. Here, the crystal structure of TxDE in the substrate-free form at 1.6 Å resolution and in complex with toxoflavin at 2.0 Å resolution is reported along with the results of a functional analysis. The overall structure of TxDE is similar to the structures of the vicinal oxygen chelate superfamily of metalloenzymes, despite the lack of apparent sequence identity. The active site is located at the end of the hydrophobic channel, 9 Å in length, and contains a Mn(II) ion interacting with one histidine residue, two glutamate residues, and three water molecules in an octahedral coordination. The binding of substrate did not cause any noticeable conformational changes in the enzyme, and toxoflavin binds in the Mn(II)-coordination shell by replacing ligating water molecules. A functional analysis indicated that TxDE catalyzes the degradation of toxoflavin in a manner dependent on oxygen, Mn(II), and the reducing agent dithiothreitol (DTT). These results provide insight into the catalytic mechanism of TxDE, its recently proposed role as a non-antibiotic selection marker for plants, and its function as an antivirulence factor in toxoflavin-mediated plant diseases.ABSTRACT.......................................................................................................I CONTENTS....................................................................................................IV LIST OF FIGURES......................................................................................VII LIST OF TABLES..........................................................................................IX LIST OF ABBREVIATIONS..........................................................................X CHAPTER I. Structural and Functional Insights into Intramolecular Fructosyl Transfer by Inulin Fructotransferase INTRODUCTION............................................................................................2 MATERIALS AND METHODS 1. Purification and crystallization of BsIFTase.............................................11 2. Purification of tetrafructosaccharides.......................................................12 3. Data collection and structure determination.............................................12 4. Site-directed mutagenesis and enzymatic activity assay..........................18 5. Analytical ultracentrifugation...................................................................18 6. Isothermal titration calorimetry................................................................20 RESULTS 1. Overall structure of monomer...................................................................22 2. Structural characteristics of turns.............................................................31 3. Trimeric structure of BsIFTase.................................................................35 4. Substrate binding site at the monomer-monomer interface......................37 5. Site-directed mutagenesis of BsIFTase.....................................................44 6. Binding of substrate to the mutant BsIFTase...........................................44 DISCUSSION..................................................................................................47 REFERENCES...............................................................................................56 CHAPTER II. Structural and Functional Analysis of Phytotoxin Toxoflavin-Degrading Enzyme INTRODUCTION..........................................................................................64 MATERIALS AND METHODS 1. Construction of TxDE Variants................................................................69 2. Expression, Purification, and Crystallization...........................................69 3. Data Collection and Structure Determination..........................................72 4. Functional analysis...................................................................................76 5. 1H-NMR Study.........................................................................................79 RESULTS 1. Overall Structure of TxDE.......................................................................86 2. Interactions between the Two Domains....................................................91 3. Active Site in the Substrate-Free TxDE...................................................93 4. Structural Features of the TxDE–Toxoflavin Complex..........................100 5. Functional Analysis................................................................................105 DISCUSSION................................................................................................109 REFERENCES.............................................................................................116 ABSTRACT IN KOREAN..........................................................................122 CURRICULUM VITAE...............................................................................125 PUBLICATIONS..........................................................................................126Docto

Studies of kinetic property of inulinase using fructo-oligosaccharides as substrate

Thesis(master`s)--서울대학교 대학원 :농생명공학부,2004.The substrate specificities of exoinulinase (2,1-¥â-D-fructan fructohydrolase, E.C. 3.2.1.80) from Bacillus sp. snu-7 (ExIB) on various fructooligosaccharides( degree of polymerization: n = 2-7) were investigated by steadystate kinetic analysis at 37 ¡É and pH 7.5. We observed that the degree of polymerization affected the Km and kcat values of exoinulinase. The subsite affinities Ai (subsite number: i = 1-7) in the active site of ExIB were as follows: A1, -0.18 kcal/mole; A2, 1.39 kcal/mole; A3, 0.136 kcal/mole; A4, 0.026 kcal/mole; A5, 0.040 kcal/mole; A6, 0.033 kcal/mole; A7, 0.085 kcal/mole, and the intrinsic rate constant, kint, was 671 min-1. Therefore, the subsite number 2 and 3, having large positive Ai values, was the most effective for the binding of small FOS to the active site. With respect to inulin with an average n = 30, its discrepancy between the calculated and observed rate parameters exceeded the experimental error, suggesting the participation of the non-productive complexes between ExIB and inulin.Maste

냉장고용 자동잠김 슬라이드의 충격 부재 최적화 설계

학위논문(석사)--서울대학교 대학원 :기계항공공학부,2006.Maste