유기 용매에서 재활용 가능한 나노반응기로서의 광-가교 되어진 고분자 큐보좀에 대한 연구

학위논문(석사) -- 서울대학교대학원 : 자연과학대학 화학부, 2021.8. 김경택.Polymer cubosomes are an emerging class of mesoporous structures formed by the solution self-assembly of block copolymers (BCPs) with a highly asymmetric block ratio. The internal nanochannel networks of a polymer cubosome provide a large surface area and internal volume to accommodate catalysts, which makes this reticulated porous structure a promising candidate for nanoreactors. Herein, we report the synthesis of BCPs composed of poly(ethylene glycol) (PEG) hydrophilic and poly(styrene-co-pentafluorostyrene) (P(pFS-co-Sty)) hydrophobic block. The pentafluorophenyl groups in the hydrophobic block could be easily functionalized with N3 groups by post-polymerization modification. The binary mixture of branched-linear and catalyst-functionalized linear BCP self-assembled into polymer cubosomes having surface-tethered catalysts, which was crosslinked by UV irradiation. We show that the resulting polymersome nanoreactors could catalyze the asymmetric aldol reaction of 4-nitrobenzaldehyde and acetone in organic solvents to yield (R)-4-hydroxy-4-(4-nitrophenyl)butan-2-one at an enhanced rate compared to the reaction catalyzed by molecular catalysts. These robust nanoreactors performed the catalysis repeatedly after multiple recycling without losing their catalytic efficiency and structural integrity.고분자 큐보좀은 고도의 비대칭 블록 비율을 갖는 블록 공중합체의 수용액상 자기조립에 의해 형성되는 복잡한 구조의 다공성 구조이다. 이러한 고분자 큐보좀이 가진 내부 나노 채널 네트워크는 촉매를 수용할 수 있는 큰 표면적과 내부 체적을 제공하는 망상 다공성 구조를 가진 나노 반응기의 유망한 후보로 볼 수 있다. 당해 연구에서는 폴리 (에틸렌 글리콜)의 친수성 부분 및 폴리 (스타이렌 -공- 펜타 플루오로스타이렌)의 소수성 블록으로 구성된 양쪽성 블록 공중합체를 합성하였다. 소수성 블록의 펜타 플루오로 페닐기는 중합 후 간단한 반응에 의해 아자이드 반응기로 쉽게 광-가교 가능하도록 기능화 하기 위해 도입되어졌으며, 분기 선형 및 촉매 기능화된 선형 블록 공중합체로 구성된 두 성분 혼합물은 수용액 상에서의 자기 조립을 거쳐 표면에 촉매가 심어진 고분자 큐보좀의 형태로 만들어졌고, 해당 구조는 자외선의 조사로 얻어낸 광-가교 반응을 활용하여 유기 용매와 같은 극한 환경에서도 복잡한 내부 형태를 유지 하는 것을 관찰 하였다. 이렇게 얻어진 고분자 큐보좀 나노 반응기는 표면에 심어진 유기 촉매에 의해 유기 용매 중에서 4- 니트로 벤즈알데히드와 아세톤의 비대칭 알돌 반응을 촉진하여 (R) -4- 히드 록시 -4- (4- 니트로 페닐) 부탄 -2- 온을 더 높은 속도로 생성할 수 있음을 확인하였다. 이에 더하여 해당 나노 반응기가 여러 번의 재활용 과정 에서도 촉매 효율과 구조적 복잡성을 잃지 않고 반복 촉매 작용을 수행하는 것을 보였다.I. Introduction 1 II. Results and Discussion 3 III. Conclusion 17 IV. Experimental Section 18 References 38 Abstract (in Korean) 41석

Percutaneous Cryoablation in Early Stage Hepatocellular Carcinoma: Analysis of Local Tumor Progression Factors

Purpose: We aimed to evaluate the effectiveness and safety of percutaneous cryoablation (PC) for early or very early stage hepatocellular carcinoma (HCC) and assess the risk factors for local tumor progression (LTP) after PC. Methods: A total of 45 treatment-naïve patients treated with PC for early or very early stage HCCs were included in this retrospective study. The safety of PC was assessed by evaluating procedure-related complications and comparing hepatic function before and after the procedure. The effectiveness was assessed by evaluating technical success, LTP rates, and disease progression (DP) rates. Prognostic factors associated with LTP after PC were also analyzed. Results: Technical success and complete response were achieved in all patients (100%) by 1 month after PC. During a mean of 28.1±15.6 months of follow-up, the incidences of LTP and DP were 11.1% and 37.8%, respectively. The LTP-free and DP-free survival rates were 93.3% and 84.4% at 1 year and 88.9% and 62.2% at 2 years, respectively. Hepatic function was normalized within 3 months after PC. There were no major complications and only one minor complication of small hematoma. On univariate and multivariate analysis, minimal ablative margin <5 mm was the only significant risk factor associated with LTP. Conclusion: PC is a safe and effective therapy for patients with early or very early stage HCC. Minimal ablative margin <5 mm was a significant prognostic factor for LTP.ope

Real-time simultaneous endoscopic combined intrarenal surgery with intermediate-supine position: Washout mechanism and transport technique

Endoscopic combined intrarenal surgery (ECIRS) with simultaneous retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) has been proposed as a new surgical treatment to overcome the disadvantage of RIRS and PCNL monotherapies in the treatment of renal stone. One of advantages of ECIRS is that it can increase stone-free rates in complex renal stone within single-session. Intermediate-supine position in real-time simultaneous ECIRS can prevent an anesthesiologic problem, and patient's burden is small even for long-term operation. Thus, we will share the experience and advantages of real-time simultaneous ECIRS and introduce techniques to increase the stone-free rate.ope

Feasibility of Deep Learning-Based Analysis of Auscultation for Screening Significant Stenosis of Native Arteriovenous Fistula for Hemodialysis Requiring Angioplasty

Objective: To investigate the feasibility of using a deep learning-based analysis of auscultation data to predict significant stenosis of arteriovenous fistulas (AVF) in patients undergoing hemodialysis requiring percutaneous transluminal angioplasty (PTA). Materials and methods: Forty patients (24 male and 16 female; median age, 62.5 years) with dysfunctional native AVF were prospectively recruited. Digital sounds from the AVF shunt were recorded using a wireless electronic stethoscope before (pre-PTA) and after PTA (post-PTA), and the audio files were subsequently converted to mel spectrograms, which were used to construct various deep convolutional neural network (DCNN) models (DenseNet201, EfficientNetB5, and ResNet50). The performance of these models for diagnosing ≥ 50% AVF stenosis was assessed and compared. The ground truth for the presence of ≥ 50% AVF stenosis was obtained using digital subtraction angiography. Gradient-weighted class activation mapping (Grad-CAM) was used to produce visual explanations for DCNN model decisions. Results: Eighty audio files were obtained from the 40 recruited patients and pooled for the study. Mel spectrograms of "pre-PTA" shunt sounds showed patterns corresponding to abnormal high-pitched bruits with systolic accentuation observed in patients with stenotic AVF. The ResNet50 and EfficientNetB5 models yielded an area under the receiver operating characteristic curve of 0.99 and 0.98, respectively, at optimized epochs for predicting ≥ 50% AVF stenosis. However, Grad-CAM heatmaps revealed that only ResNet50 highlighted areas relevant to AVF stenosis in the mel spectrogram. Conclusion: Mel spectrogram-based DCNN models, particularly ResNet50, successfully predicted the presence of significant AVF stenosis requiring PTA in this feasibility study and may potentially be used in AVF surveillance.ope

Balloon Bronchoplasty for the Treatment of Bronchial Stenosis After Lung Transplantation: A Single-Center 10-Year Experience

Objective: To assess the safety and efficacy of balloon dilatation under dual guidance using fluoroscopy and bronchoscopy for treating bronchial stenosis following lung transplantation (LT), and to elucidate the factors associated with patency after the procedure. Materials and Methods: From September, 2012, to April, 2021, 50 patients (mean age ± standard deviation, 54.4 ± 12.2 years) with bronchial stenosis among 361 recipients of LT were retrospectively analyzed. The safety of balloon dilatation was assessed by evaluating procedure-related complications. Efficacy was assessed by evaluating the technical success, primary patency, and secondary patency. Primary and secondary cumulative patency rates were calculated using the Kaplan-Meier method. The factors associated with patency after the procedure were evaluated using multivariable Cox hazard proportional regression analysis. Results: In total, 65 bronchi were treated with balloon dilatation in 50 patients. The total number of treatment sessions was 277 and the technical success rate was 99.3% (275/277 sessions). No major procedure-related complications were noted. During the mean follow-up period of 34.6 ± 30.8 months, primary patency was achieved in 12 of 65 bronchi (18.5%). However, the patency rate improved to 76.9% (50 of 65 bronchi) after repeated balloon dilatation (secondary patency). The 6-month, 1-year, 3-year, and 5-year secondary patency rates were 95.4%, 90.8%, 83.1%, and 78.5%, respectively. The presence of clinical symptoms was a significant prognostic factor associated with reduced primary patency (adjusted hazard ratio [HR], 0.465; 95% confidence interval [CI], 0.220–0.987). Early-stage treatment ≤ 6 months (adjusted HR, 3.588; 95% CI, 1.093– 11.780) and prolonged balloon dilatation > 5 min (adjusted HR, 3.285; 95% CI, 1.018–10.598) were associated with significantly higher secondary patency. Conclusion: Repeated balloon dilatation was determined to be safe and effective for treating bronchial stenosis following LT. Early-stage treatment and prolonged balloon dilatation could significantly promote long-term patency.ope

출판-구독 시스템을 위한 효율적인 XML 필터링 기법

Thesis(doctors) --서울대학교 대학원 :전기. 컴퓨터공학부, 2009.2.Docto

(A) clinical study on the patients with acute infection of the oral and maxillofacial region

치의학과/석사[한글] 저자는 1984년 1월부터 1989년 10월까지 5년 10개월 동안 구강·악안면부위의 급성감염으로 인하여 연세의료원에서 입원가료를 받은 남자 97명, 여자 67명, 총 164명의 병록지를 검토하여 다음과 같은 결론을 얻었다. 1. 원인별로는 치성(odontogenic)이 50.1%로 가장 많았으며, 발치후 감염예도 10중례(6.1%)나 되었다. 2. 침범한 근막간극은 Submandibular space(31.3%), Submental space(14.8%), Neck(11.7%), Buccal space(10.9%)의 순 이었으며 Ludwig's angina도 11예(4.8%)나 발견되었다. 또한 침범한 근막간극의 수는 하나의 간극만 침범한 경우가 59.8%, 둘 이상인 경우가 32.2%이었다. 3. 치료방법은 모든 경우에 대중요법과 항생요법이 시행되었고, 외과적 절개 및 배농술이 전체 환자의 76.8%에서, 원인치아의 발거 및 처치가 전체환자의 33.0%에서 시행되었다. 4. 농배양에서 분리된 원인균주는 Streptococci(42.4%), Staphylococci(27.1%), Neisseria(9.3%), Bacteroides(7.0%), Pseudomonas(3.5%)와 E. coli(3.5%)의 순 이었다. 5. 사용된 항생요법은 Cephalosporin과 Aminoglycoside의 병용(32.9%), Penicillin과 Aminoglycoside의 병용(29.9%), Cephalosporin, Aminoglrcoside와 함께 Metronidazole의 투여(14.1%)의 순으로 전체 환자의 약 85%에서 두가지 이상의 항생제가 동시에 사용되었다. [영문] This is a retrospective study on the patients with acute inflection of the oral and maxillofacial region of Yonsei Medical Center for the period of Jan. 1984 to Oct. 1989. The number of the patients involved in this study were 164 in total, including 97 male patients and 67 female patients. The results obtained were as follows: 1. The most frequent cause of acute infection of this region was odontogenic(50.1%), and in 10 patients the symptom aggravated after teeth extraction. 2. The most common fascial spaces involved were Submandibular space(31.3%), Submental space(14.87)),Neck(11.7%), Buccal space(10.9%) in order, and 11 cases(4.8%) were Ludwig's angina. In 59.8% of the patients, the infection involved only one fascial space and in 32.2% of the patients, it involved two or more fascial spaces. 3. Antibiotics were administrated in all of the cases, and surgical incision and drainage were performed in 76.8%, and extraction or treatment of the causative teeth were performed in 33.0% of all cases. 4. The causative organisms isolated from pus culture were Streptococci(42.4%), Staphylococci(27.1%), Neisseria(9.3%), Bacteroides(7.0%), Pseudomonas(3.5%) and E. coli(3.5%). 5. The most commonly used antibiotics in the treatment were combination of Cephalosporin and Aminoglycoside(32.9%), combination of Penicillin and Aminoglycoside(29.9%), and combination of Cephalosporin, Aminglycoside and Metronidazole(14.1%).restrictio

신경에 대한 비가역적 전기천공술의 효과: 토끼 모델을 이용한 병리학적, 기능적 분석

배경: 비가역적 전기 천공술은 전극을 통해 박동성 고전압 전류를 이용하는 비열 절제 기술이다. 최근 비가역적 전기천공술은 췌장, 간 및 전립선을 비롯한 다양한 종양 치료에 사용되고 있다. 본 연구는 토끼 모델에서 신경에 대한 비가역적 전기천공술의 시기에 따른 효과를 평가하고자 하였다. 방법: 연구 집단은 뉴질랜드 수컷 흰 토끼로 대조군 1마리와 실험군 7마리로 총 8마리로 구성되었다. 7마리의 실험군에 대하여 초음파 유도하에 대퇴 신경 혈관 다발에 대하여 비가역적 전기천공술을 시행하였다. 기능적 평가와 병리학적 평가는 비가역적 전기천공술 후 3일, 1주, 2주, 3주, 4주, 6주 및 8주에 순차적으로 시행하였다. 기능적 분석은 modified Tarlov scale을 이용하였다. 모든 신경 조직 및 주변 조직은 신경 손상과 재생을 나타내는 축삭 부종, 분열, 손실 및 재생, Schwann 세포 손실 및 증식, 타원체 및 염증 세포 침윤과 섬유증에 대한 병리적 소견에 대하여 평가하였다. 신경의 손상 정도는 영향을 받은 신경다발의 비율로 분석하였으며 주변 조직의 손상은 영향을 받은 부분의 면적의 비율로 분석하였다. 결과: 비가역적 전기천공술 후 modified Tarlov scale상 4주간 기능적 손상이 나타났으나, 점차 정상으로 회복되었다. 병리학적 검사상 신경 주변 조직의 염증세포 침윤은 시술 3일 후 가장 심했으며 80-85%로 측정되었다. 신경 주변 조직의 손상 및 응고 괴사는 시술 3일에서 1주일 후에 80-90%로 가장 심하였으며 점차 회복되었고 일부는 섬유성 흉터로 대치되었다. 한편, 신경 섬유는 시술 1-2주 후에 가장 심하게 파괴되었으며, 영향을 받은 신경 섬유의 비율은 80-100% 였다. 그 후 점차 회복되어 시술 8주 후 정상으로 회복되었다. 결론: 비가역적 전기천공술 후 신경의 손상과 함께 기능적 손상이 발생할 수 있다. 하지만, Schwann 세포의 재생과 더불어 신경 내, 외막의 보존은 8주 이내에 신경 조직의 재생을 유도할 수 있다. 따라서 비가역적 전기천공술은 신경에 인접한 종양의 잠재적 치료 방법이 될 수 있다. Background: Irreversible electroporation (IRE) is a non-thermal ablation technique using pulsatile high-voltage current through electrodes. Recently, IRE is being used to treat various tumors, including pancreas, liver and prostate. The aim of this study was to sequentially evaluate the effects of IRE on nerve during acute to delayed periods in a rabbit model. Materials and Methods: The study population consisted of 8 male New Zealand White rabbits; 1 rabbit for control subject and 7 for IRE subjects. Ultrasound guided IRE of femoral neurovascular bundles was performed in 7 rabbits. Functional assessment and histopathologic evaluation was performed sequentially at 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks and 8 weeks after the IRE. Functional assessment was addressed independently immediately after the procedure and then every two days until euthanasia using modified Tarlov scale. All nerves and surrounding tissues were assessed for histopathologic findings consistent with nerve injury and repair, such as axonal swelling, fragmentation, loss, and regeneration, Schwann cell loss and proliferation, ellipsoids, inflammatory cell infiltrates, and fibrosis. The proportion of nerve fiber affected and the area proportion of perineurial inflammation and surrounding tissue injury were recorded. Results: After IRE, the modified Tarlov scale showed that the femoral nerve function was damaged before 4 weeks, but then the femoral nerve function recovered gradually to normal. The area of perineural inflammatory infiltration was marked in 3 days after IRE, ranging from 80 to 85% and, was normalized after 8 weeks. Surrounding tissue injury and coagulative necrosis was prominent in 3 days and 1 week after IRE, ranging from 80 to 90%, and recovered after that with fibrous scar. On the other hand, the peripheral nerve fibers were marked destructed in post 1 and 2 weeks with proportion of the affected nerve fiber varied from 80-100%. And then, the nerve fibers became recovered, and normalized after 8 weeks. Conclusion: The nerve tissues injury with functional impairment can occur after IRE. However, endoneurium and epineurial extracellular matrix are preserved with Schwann cell regeneration, which can lead to regeneration of nerve tissues within 8 weeks. Therefore, IRE may be a potential treatment modality for the tumors that involves a major nerve.open박

간세포암에서의 DEB-TACE를 이용한 치료의 임상적 안정성과 치료 반응률

Dept. of Medicine/석사OBJECTIVE: To assess the tumor response rate and clinical safety of transarterial chemoembolization using drug-eluting beads (DEB-TACE) in patients with hepatocellular carcinoma.MATERIALS AND METHODS: Between September 2009 and January 2011, eighty-one patients with 100 HCCs were included in this study. All patients underwent pre-procedural MDCT or magnetic resonance imaging for evaluation of tumor stage. Four experienced interventional radiologists had performed DEB-TACE for hypervascular HCC. Before and after treatment, liver function status (Child-Pugh class) and tumor stage (BCLC and mUICC criteria) were evaluated. MDCT and MRI were performed 4~8 weeks after DEB-TACE to evaluation of tumor response. And, statistical correlation was calculated between angiographic findings and tumor response. Also, relation tumor stage and tumor response was calculated. Finally, post-procedural complications were evaluated by symptoms and image findings.RESULTS: For total of 81 patients, 71 were Child-Pugh class A and 10 were Child-Pugh class B before treatment, and 67 were Child-Pugh class A, 13 were Child-Pugh class B and 1 were Child-Pugh class C after treatment. For a total of 100 treated HCCs, immediate complete response (CR) according to mRECIST and EASL was seen in 74 lesions. Partial response (PR) lesions were 14 according to mRECIST and 13 in EASL, stable disease (SD) were 5 according to mRECIST and 6 in EASL, and disease progression (PD) were 7 according two response criteria. Tumor progression free survival rate were 65.2% during 1-year follow-up. There was no statistical significance between tumor stage and tumor response. Of angiographic findings, feeder hypertrophy, neovascularization and multiple feeder were correlated with tumor response, showing statistical significance. Of total 81 patients, localized bile duct dilatation were shown in 39 patients (48.1%), peritumoral parenchymal ischemic change were shown in 10 patients (12.4%) and post-embolization syndrome were shown in 7 patients (8.6%).CONCLUSION: DEB-TACE was considered as a safe modality for the treatment of HCC, and showed acceptable tumor response rate as well as tumor progression free rate in this mid-term result.ope

내장형 시스템을 위한 재구성 가능한 고성능 저전력 메모리 구조의 설계

학위논문(석사)--서울대학교 대학원 :전기.컴퓨터공학부,2001.Maste