Multifunctional Nanodroplets Encapsulating Naphthalocyanine and Perfluorohexane for Bimodal Image-Guided Therapy

Choi, Hyunsik,Choi, Wonseok,Kim, Jeesu,Kong, Won Ho,Kim, Ki Su,Kim, Chulhong,Hahn, Sei Kwang American Chemical Society 2019 Biomacromolecules Vol.20 No.10

<P>Although nanocarriers containing perfluorocarbon (PFC) have been widely investigated as an ultrasound (US) imaging agent and a high intensity focused ultrasound (HIFU) agent, these carriers have suffered from low stability and biocompatibility limiting their further biomedical applications. Here, we developed surface cross-linked polymer nanodroplets as a HIFU therapeutic agent guided by bimodal photoacoustic (PA) and US imaging. Pluronic F127 was reacted with 4-nitrophenyl chloroformate (NPC) and mixed with naphthalocyanine (Nc) in dichloromethane, which was added into the aqueous solution of amine-functionalized six-arm-branched poly(ethylene glycol) (PEG) to form an oil-in-water emulsion for the cross-linking reaction between the terminal NPC of Pluronic F127 and the primary amine of six-arm PEG. The resulting solution was sonicated with liquid perfluorohexane (PFH) to prepare PEG cross-linked Pluronic F127 nanoparticles encapsulating Nc and PFH (Nc/PFH@PCPN). Nc/PFH@PCPN appeared to be stable without any coalescence or vaporization in the physiological condition. Upon the application of HIFU, Nc/PFH@PCPN was vaporized and showed increased US intensity for 180 min. The Nc dye in the nanodroplets enabled the stable encapsulation of PFH and the bimodal US/PA imaging. In vivo PA/US image-guided HIFU ablation therapy confirmed that the nanodroplets increased the cavitation effect, induced necrosis and apoptosis of tumor cells, and reduced tumor growth significantly for 12 days. Taken together, the multifunctional Nc/PFH@PCPN was successfully developed as a new platform for PA/US image-guided HIFU therapy.</P> [FIG OMISSION]</BR>

Quality monitoring of resuscitative endovascular balloon occlusion of the aorta using cumulative sum analysis in Korea: a case series

Choi Hyunsik,Kim Joong Suck,Yeo Kwanghee,Kwon Ohsang,Kim Kyounghwan,Kang Wu Seong 대한외상학회 2023 大韓外傷學會誌 Vol.36 No.2

Purpose: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a state-of-the-art lifesaving procedure. However, due to its high mortality and morbidity, including ischemia and reperfusion injury, well-trained medical staff and effective systems are needed. This study was conducted to investigate the learning curve for REBOA. Methods: To monitor this learning curve, we used cumulative sum (CUSUM) analysis and graphs of mortality and aortic occlusion time within 60, 90, and 120 minutes for consecutive patients. The procedures performed between July 2017 and June 2021 were divided into pre-trauma center (pre-TC; July 2017–February 2020) and TC (February 2020–June 2021) periods. Results: REBOA was performed for 31 consecutive patients with trauma. The pre-TC (n=12) and TC (n=19) periods did not differ significantly with regard to Injury Severity Score, age, injury mechanism, initial systolic blood pressure, prehospital cardiopulmonary resuscitation (CPR), or CPR in the emergency department. At the 17th consecutive patient during the TC period, CUSUM failure graphs for mortality and aortic occlusion time exhibited a downward inflection, indicating an improvement in performance. Conclusions: The mortality and aortic occlusion time of REBOA improved, and these parameters can be monitored using CUSUM analysis at the hospital level.

기존 시스템 기반의 소프트웨어 제품라인 공학 기법 : 케이블 셋톱박스 소프트웨어 사례

최현식(Hyunsik Choi),이혜선(Hyesun Lee),조윤호(YoonHo Cho),강교철(Kyo Chul Kang) 한국정보과학회 2009 정보과학회논문지 : 소프트웨어 및 응용 Vol.36 No.7

산업 및 가전 제품에서 소프트웨어의 중요성이 커지면서 소프트웨어 재사용과 제품라인 방법론에 대한 관심이 높아지고 있다. 그러나 대부분의 제품라인 방법론은 초기 비용과 시간이 많이 들고 구체적인 절차나 성공 사례가 부족하여 산업체에서 적용하기에는 어려운 한계가 있다. 본 논문에서는 산업체에서 제품라인 기법을 쉽게 적용할 수 있도록, 기존에 개발된 소프트웨어 자산과 해당 도메인의 휘처모델을 활용하여 제품라인을 쉽게 구축할 수 있는 추출식 접근법의 구체적인 방법을 제시하고 이를 케이블 셋톱박스 소프트웨어에 적용한 사례를 소개한다. 또한, 제품라인으로의 전환 효과를 확인할 수 있는 평가 기준을 제안하고, 사례 연구를 통해 얻은 교훈을 정리하여 다른 산업 및 가전 제품의 소프트웨어에 적용할 수 있는 지침을 제공한다. Software product line (SPL) engineering is an emerging paradigm for successful software reuse and has been adopted for various industrial and consumer products to improve their productivity and quality. However, most SPL methods require high initial costs and long development time, which makes many companies hesitate to adopt the SPL paradigm. In this paper we introduce a method to construct an SPL by extracting core assets from legacy components based on the feature model, which requires less initial time and effort. We also present a case study on cable set-top box software to illustrate the applicability of this method, and lessons learned that will provide guidelines for many companies to adopt the SPL paradigm.

서버 가상화 환경에서 이주 횟수를 최소화하는 시뮬레이션 기반 이주 알고리즘

최현식(Hyunsik Choi),고영록(Youngrok Ko),박성용(Sungyong Park) 한국정보과학회 2011 정보과학회논문지 : 시스템 및 이론 Vol.38 No.4

서버 가상화 환경의 이주 시스템은 자원이 부족한 물리서버의 가상서버를 자원이 넉넉한 물리서버로 이주시켜서 부하를 분산시키며, 그를 바탕으로 물리서버의 자원 부족 문제를 해결한다. 기존의 이주 시스템들은 적재 문제의 효과적인 해결책인 최초 적합 알고리즘을 통해 이주 정책을 결정한다. 하지만 가상서버의 자원 사용량은 계속적으로 변하므로, 단순한 알고리즘을 통해 최적의 이주 시나리오를 도출할 수 없다. 따라서 그를 기반으로 하는 시스템은 더 많은 이주를 발생시키고, 그에 따른 추가적인 비용이 소모된다. 본 논문에서는 가상서버 자원 중 CPU 사용률의 예측치를 바탕으로 시뮬레이션을 수행하여, 예측 구간 내에서는 최적의 이주 정책을 수행하는 추가 이주 최소화 알고리즘을 제안한다. 제안하는 추가 이주 최소화 알고리즘은 목적지 물리서버를 결정할 때, 가상서버를 수용할 수 있는 모든 물리서버에 대한 이주가 가능하다고 가정하고, 각각의 경우를 시뮬레이션 하여 이주 횟수를 최소화하는 이주 시나리오를 이주 정책으로 결정한다. 따라서 제안하는 이주 알고리즘은 미래 CPU 요구량을 정확히 분석하여, 가상서버의 응용 프로그램에 높은 서비스 만족도를 제공하면서, 이주 횟수를 감소시켜 이주 시스템의 비용을 절감한다. Migration systems in server virtualization environments distribute workloads and solve resource shortage problems by moving a virtual machine in hotspot to a physical server having residual resources. Most of the migration systems use first fit algorithm known as an efficient solution for bin packing problem to determine migration policies. However, the algorithm cannot provide an optimal migration scenario, because the resource usage of virtual servers continuously changes. Consequently, the migration systems based on the algorithm issue more migrations and increase the cost of the physical servers. In this paper, we propose a simulation-based migration manager producing an optimal migration policy for its own window by simulating the forecasted CPU usages of virtual machines. The simulation-based migration algorithm assumes that every physical server with enough residual capacity to serve a victim can be a candidate destination and simulates a migration on each server. The algorithm finally selects a migration scenario whose expected number of migrations is the lowest. The system consequently, provides applications with high quality of service through accurate analysis and reduces the migration cost by minimizing the number of migrations.

셀 상태 값을 이용한 연속 스카이라인 질의

최현식(Hyunsik Choi),강상원(Sang-Won Kang),정하림(Ha-Rim Jung),구원교(Won-Kyo Ku),정승희(Seung-Hee Chung),황종선(Chong-Sun Hwang),이상근(SangKeun Lee) 한국정보과학회 2007 한국정보과학회 학술발표논문집 Vol.34 No.2A

일반눈문 : 조선 철도창가의 기억과 향유를 위하여 -6편의 철도창가 소개와 개관

최현식 ( Hyunsik Choi ) 한국문학연구학회 2015 현대문학의 연구 Vol.0 No.57

이 논문은 조선 철도창가 6편을 소개하고 해석하기 위해 작성된다.「경인철도가」 「경의철도가」 「경원철도가」 「호남철도가」 「경주행진곡」 「마산행진곡」이 해당 텍스트들이다.이것들은 「철도 100년 가요집」 및 코레일 홈페이지 ‘역사관’에 수록되어 있다.책자는 비매품이며 특정 회사의 홈페이지에 올라 있는 바람에 귀중한 철도창가 6편의 소재를 알기 어려웠다.본고는 6편을 ‘조선 강토의 종횡단’과 ‘철도 여행의 양가성’이라는 대주제 아래 분류하여 그 의미와 가치를 해석했다.6편의 특질 및 성격을 규명하기 위해 일본 「철도창가」 및 최남선의 「경부텰도노래」를 모본 삼았다.특히 영향과 수용의 양 측면을 초점 삼아, 6편 철도창가의 문명성과 식민성을 밝히고자 했다.결론에서 조선총독부 산하의 「조선철도국국가」와 소학교 「창가」교과서의 「조선철도창가」를 따로 읽어본 것도 그 때문이다.6편에서는 대체로 철도문명이 가져온 속도성과 도회의 발전, 여행의 편리함과 노선 특유의 풍경이 노래되고 있다.요컨대 조선철도의 실질적 주체였던 일제의 식민 정책과 그에 따른 조선의 저개발 현상은 거의 관심을 받지 못했으며 심지어 은폐된다는 느낌도 있었다.그러나 문명의 표지가 압도하는 가운데서도 ‘조선적인 것’의 새로운 발견과 이해가 이루어지고 있다는 것이 본 연구의 최종적 판단이었다. This study is intended to introduce and analyze Chosun’s six railroad songs. “Gyeongincheoldoga”, “Gyeonguuicheoldoga”, “Gyeongwoncheoldoga”, “Honamcheoldoga”, “Gyeongjuhaengjingok”, and “Masanhaengjingok” are the text. These are contained in 100 Years of Railroad Songs Collection and Korail’s homepage, ‘Yeoksagwan’. The book is not for sale, and they are uploaded on a particular company’s homepage, so it was hard to know the whereabouts of those previous six railroad songs. This study classified the six songs with two major topics, ‘Traveling around the land of Chosun’ and ‘double-sidedness of railroad trips’, and analyzed their meaning and value. To examine the six songs’ characteristics and features, this study takes Japan’s Tetsudo Syoka(Railroad Songs) and Choi Namseon’s Gyeongbucheoldonorae as examples. Particularly focusing on the two aspects of influence and acceptance, this author intended to figure out the civilization and colonial aspects of those six railroad songs. This is the reason why this study deals additionally with 「Chosunrailroad gukga」 and “Chosen Tetsudo Syoka” of elementary school’s Songs textbooks under the Japanese Government General of Korea in its conclusion. The six songs generally sing about the speediness coming from railroad civilization, development of cities, convenience in traveling, and the unique landscapes of each line. In fact, it seems that the colonial policy of Japan that was the real subject of Chosun railroads and underdevelopment in Chosun resulted from it were almost not recognized and even got to be hidden somehow. However, this study has finally concluded that even though the cover showing civilization is overwhelming, there really was new discovery and understanding of ‘what is Chosun-style’.

‘도시 산책자’에서 ‘광장의 투사’로 : 남북한문학사에서 박팔양 시의 위상과 가치

최현식 ( Choi Hyunsik ) 국제비교한국학회 2021 비교한국학 Comparative Korean Studies Vol.29 No.3

이 글은 남한, 만주, 북한의 세 공간에서 펼쳐진 박팔양의 굴곡진 삶과 시의 궤적을 살펴보기 위해 작성된다. 1920년대 등단한 그는 카프(KAPF)와 구인회 활동을 하며 이념적 시, 다다이즘 시, 식민도시 관련 시 등 다양한 창작 활동을 벌였다. 이후 일제가 통치하던 만주로 건너가 ‘오족협화’ 이념에 충실한 시를 몇 편 쓰면서 친일적인 ‘만주국협화회’의 일을 보기도 한다. 1945년 해방이 되자 그는 북한을 선택하여 사회주의 문학과 체제의 건설에 주력한다. 친일과 월북으로 상징되는 불온한 이력은 그의 작품이 남한에서 금지 처분을 당하는 핵심 요인이 된다. 1960년대 중반까지 북한문단에서 승승장구하던 그는 김일성 유일사상을 모독했다는 혐의로 숙청되어 창작의 펜을 빼앗기게 된다. 남북한에서 동시에 고초를 겪던 박팔양의 시는 1980년 후반 들어 극적인 생환을 이룬다. 남한에서는 첫 시집 『여수시초』(1940)를 중심으로 해방전의 시가 모두 복권된다. 북한에서 창작된 서정시도 수십 편 소개되는데, 대체로 사회주의 이념성이 두드러지지 않는 것들이었다. 북한에서는 1990년대 이후 본격화된 『현대조선문학선집』의 편찬 과정에서 해방 이전의 시가 대거 수록된다. 이 문학적 사건을 이해하기 위해서는 1959년과 1992년에 발행된 『박팔양 시선집』의 동일성과 차이성을 밝히는 것이 중요하다. 두 시선집 모두 해방 전~1950년대 시를 수록하고 있으며, 사회주의 체제에 대한 신념과 열정을 중시하고 있다. 하지만 1992년의 『박팔양 시선집』은 서시와 결시를 김일성주의와 김정일 지도체제에 대한 찬양이라는 ‘정치의 예술화’로 확연히 경도되고 있다. 문제는 서시와 결시가 박팔양 사후에 ‘유고시’ 형태로 발표되고 있다는 사실이다. 만약 두 시가 박팔양의 창작이라면, 해방 이전 시편을 복권시키기 위해 의도적으로 김일성과 김정일 찬양의 길을 선택한 것으로 이해된다. 반대로 시인의 이름을 빌려 북한의 수령 영도 체제를 빛내고자 했다면 가장 타락한 형태로 한 시인의 영혼과 작품을 날조한 것이 된다. This article is written to take a look at the turbulent life and time of Park Pal-Yang who spent time in three spaces of South Korea, Manchuria and North Korea. With his emergence in 1920s, he engaged in KAPF and Guinhoe activities to work on various creative work activities in ideological poetry, dadaism poetry, colonial city related poetry and others. Thereafter, he went to Manchuria that was under the ruling of the Japanese Imperialist to write a few poems with the ‘Ojokhyephwa(Japanese initiated movement to have united cooperation of five races in the area)’ ideology and engaged in pro-Japanese ‘Manchuria National Hyeophwahoe’ affairs. In 1945, upon the liberation, he opted for North Korea to focus on constructing socialist literature and system. His unfortunate record of pro-Japan and opting for North Korea became the key factor to sanction him to prohibit his works in South Korea. By the middle of 1960s, he was in the main stream in the North Korean literature sector but he was prosecuted for insulting the only ideal of Kim Il-Sung that hie pen for creative work was taken away. The poems of Park Pal-Yang who had the troubled water in both South and North Korea at the same time came back dramatically in late 1980s. In South Korea, his poems before the liberation including his first poetry collection Yeosusicho (1940) were all restored. In North Korea, tens of his creative works in lyrics were introduced and most of such works were not specifically displaying the socialist ideology. In North Korea, many of his poems before the liberation was recorded in the compilation process of Contemporary Joseon Literature Collection that was undertaken in full scale after 1990s. In order to understand this literature event, it is important to disclose the identical points and different features of Park Pal-Yang Poetry Collection published in 1959 and 1992. These two poetry collections have the poems of pre-liberation period ~ 1950s, and both places conviction and passion on the socialist system. However, the Park Pal-Yang Poetry Collection of 1992 clearly tilted toward the ‘politics-focused arts’ with its introductory poem and concluding poem in praising Kim Il-Sung-ism and Kim Jeong-il leadership system. The issues are that the introductory poem and concluding poem were published in the ‘passing poetry’ type after the death of Park Pal-Yang. If these two poems were creative works of Park Pal-Yang, it could be understood as opting the path of praising Kim Il-Sung and Kim Jeong-il with the intent to restore the poetry works before the liberation. Conversely, if it was intended to borrow the name of a poet to propaganda the leadership system of North Korea, it would be the falsification of a soup and works of a poet in most corrupted way.

HILS를 활용한 주행에 따른 1000V급 전기차용 고전압 릴레이의 성능 변화 분석

최태일(Taeil Choi),최재영(Jaeyoung Choi),송현식(Hyunsik Song) 한국자동차공학회 2023 한국자동차공학회 학술대회 및 전시회 Vol.2023 No.11

방사선 치료 시 종양선량을 예측하는 방법에 관한 연구

최종학,고현식,이병구,김유현 高麗大學校 倂設 保健大學 保健科學硏究所 2003 保健科學論集 Vol.29 No.2

The aim of this study is to develop a simple method which computes in-vivo doses from transmission doses measured during patient treatment using an ionization chamber. Energy fluence and the dose that reach the chamber positioned behind the patient is modified by three factors : patient attenuation, inverse square attenuation, and scattering. We adopted a straightforward empirical approach using a phantom transmission factor (PTF) which accounts for the contribution from all three factors. It was done as follows. First of all, the phantom transmission factor was measured as a simple ratio of the chamber reading measured with and without a homogeneous phantom in the radiation beam according to various field sizes(r_(p)) and phantom thickness(T_(p)). Secondly, we used the concept of effective field to the cases with irregular fields. The effective field size is calculated by finding the field size that produces the same value of PTP to that for the irregular field. The hypothesis is that the presence of irregular field can be accommodated to a certain extent by altering the field size. Thirdly, the center dose at the prescription depth can be computed using the new TMR(r_(p,eff)) and Sp(r_(p,eff)) from the effective field size. After that, when TMR(d, r_(p,eff)) and S_(p)(r_(p,eff)) are acquired, the tumor dose is as follows. D_(center) = D_(t)/PTF(d_(g), T_(p))×(SCD/SAD)²×S_(p)(r_(p,eff))×TMR(d, r_(p,eff)) As the field size increased, the errors showed a tendency to increase. Generally, with this method the absolute midline, dose was predicted with an accuracy of about 2.53% and 2.37% for 6 MV and 10MV X-rays. A simple method of in-vivo dose reconstruction and verification was developed. The efficacy of this method is limited by the field size. Thus, the method developed in this study should be used with care for relatively large field sizes. Further clinical test awaits this study.

Fully Integrated CMOS PAs with Two-Winding and Single-Winding Combined Transformer for WLAN Applications

CHOI, Se-Eun,AHN, Hyunjin,RYU, Hyunsik,NAM, Ilku,LEE, Ockgoo 'Institute of Electronics, Information and Communi 2018 IEICE transactions on electronics Vol.101e.c No.12