Nature-inspired nanoparticles coated with glycosaminoglycan-photosensitizer for cancer specific therapy

이창주,한지은,박신정,나건,박우람 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

To treat cancer more effectively, combination therapy has been studied with photodynamic therapy(PDT). We designed nature-inspired polymer nanoparticles which have biocompatibility and photothermal effect under NIR condition. These nanoparticles coated with glycosaminoglycan that is also biocompatible natural polymer and able to target cancerous cells. Photosensitizer(PS), a powerful reactive oxygen species (ROS) generator, is conjugated with glycosaminoglycan so that photodynamic effect can be controllable. Cancer specific therapy is an important issue in PDT, because of unwanted side-effects. Our nanoparticles(NGPs) have high water solubility, cancer selective internalization, controlled toxicity under laser irradiation condition and enhanced anticancer activity with photothermal effect. We suggest that NGPs are a promising combination cancer therapy agent.

내분비계 장애물질이 생식계에 미치는 영향

이창주,이호준,윤용달 대한내분비학회 2001 Endocrinology and metabolism Vol.16 No.5-6

Application of Electrohydraulic Proportional Valve for Steering Improvement of an Autonomous Tractor

이창주,전찬우,한웅철,김정훈,김학진 한국농업기계학회 2022 바이오시스템공학 Vol.47 No.2

Purpose The most common solution to achieving automated steering in an agricultural tractor is the use of electric motors along with conventional manual steering systems called an electric power steering (EPS) system. However, EPS systems have limited use in automated tractor steering requiring fast and accurate responses. Another solution is to use the electrohydraulic proportional (EHPV) valve technology, but EHPV systems have highly nonlinear characteristics. The objective of this study is to develop an electrohydraulic (E/H) steering system that is applicable to a conventional steering circuit and to compare the performance with an EPS system. A proportional-feedforward control algorithm was implemented to effectively compensate for the nonlinear behaviors of EHPV systems. Methods A computer-controlled hardware-in-the-loop E/H steering simulator consisting of EPS and EHPV subsystems was designed and built to develop the steering control algorithms and to verify the feasibility of the developed steering controller. A field test was conducted using a real-time kinematic GPS-based autonomous tractor equipped with the developed E/H steering system and an EPS system as a control to compare and investigate their potentials. Results Compared with the EPS system, the use of the E/H steering system was shown to improve the tracking errors by about 29% and 50% for straight and curved paths at a speed of 2 km/h and about 85% for straight path at a speed of 5.5 km/h. Conclusions The proportional-feedforward steering controller is the feasible solution to controlling and reducing any nonlinear characteristics and is a suitable steering system for high-speed operations.

돼지 난소내 과립세포의 염색질이상응축과 여포액내 스테로이드호르몬의 농도 변화와의 상관관계

이창주,윤용달,김종흡,김문규,Lee, Chang-Joo,Yoon, Yong-Dal,Kim, Jong-Heup,Kim, Moon-Kyoo 대한생식의학회 1989 Clinical and Experimental Reproductive Medicine Vol.16 No.1

In order to study the follicular atretic mechanism in mammalian ovary, the relationship between pyknotic index (PI) of granulosa cells and the steroid concentrations in the follicular fluid of atretic follicle was investigated. Follicles were isolated from porcine ovary according to their sizes and the reproductive phases. Steroid concentrations were quantified by high-performance liquid chromatography. As PI increased, the concentration of progesterone was significantly increased(p<0.05), whereas testosterone and estradiol showed no significant changes in their concentration. As follicular size was increased, PI of follicular GC in the luteal phase was increased significantly(p<0.05) and the molar ratio of progesterone to testosterone was increased in the follicles of follicular phase. It can be concluded that progesterone accumulated in the follicular fluid as atresia of the follicles was progressed, and that PI of granulosa cells could be used as one of convenient and pratical criteria for the identification of follicular atresia.

The Advantages of Rectangular Titanium Cage(RABEA) Fusion after Anterior Cervical Discectomy : Comparative Study of Fusion Allograft

이창주,이동열,허원,윤재웅,박화성 대한신경외과학회 2004 Journal of Korean neurosurgical society Vol.36 No.6

Objective : To study the safety and efficacy of using rectangular titanium cage(RABEA) for anterior cervical fusion, we have compared the results of fusion performed by using fibula allograft and RABEA cage. Methods : Total of 74 patients with single level cervical discectomy were included in this study. Allogenic fibula bone graft alone was done in 38 patients and RABEA cage was inserted in 36 patients. Retrospective clinical analysis was based on review the symptoms and radiological findings on both two groups at postoperative 12 months. Results : Solid fusion was achieved in 95% of patients who received rectangular titanium cage and 74% of patients who received fibula allograft. According to Odom's criteria, 92% of patients were found to have excellent or good results in the RABEA cage group and 68% of patients in allograft group. Functional outcome was assessed according to Odom's criteria and patient's postoperative satisfaction index(PSI). Better clinical outcome and solid fusion could be achieved by rectangular titanium cage fusion than allogenic fibula graft after single level anterior cervical discectomy. Conclusion : We believe that RABEA cage is an effective and safe cervical fusion substitute for single level cervical fusion after discectomy.

문자와 식 영역의 정형문제 해결지도에서 식에 따른 수학적 사고 형식과 모델 설정에 관한 연구

이창주 공주교육대학교 초등연구원 2006 公州敎大論叢 Vol.43 No.2

In this paper, I classified and arranged the thinking form related to the formulas representation to solve the formal problem. On the classification of the basic thinking form, I had a basis on the problem-solving methods by the formulas required for the teaching in solving the examples given in the textbooks. The thinking form was classified in the several cases according to the relevance of the formulas. For the respective cases of the classified thinking form, I searched for the ideas necessary for the meaning, stages, and characteristics of the teaching. To solve the formal problem requested as the basic thinking for problem-solving methods, I studied the basic thinking form and the model-posing methods necessary for the teaching of operations and formulas. 본 연구에서 문자와 식 영역의 정형 문제 해결을 위한 사고 형식에 대하여 식의 표현에 따라 분류 정리하여 보았다. 기본적 사고 형식의 분류는 연산을 중심으로 교과서에 제시된 문제의 해결에서 교육적으로 기대하는 식에 의한 해결 방법을 근거로 하였다. 사고 형식은 식의 관련성에 의하여 몇 개의 경우로 분류하였다. 분류된 각각의 사고 형식에 대하여 지도상의 의미, 단계, 특성 등과 같은 지도상 필요한 아이디어를 찾아보았다. 또한 각각의 사고 형식에 대하여 모델 설정의 관점에서 동형성, 다양성, 적절성 등의 조건에 따른 모델 설정 방안에 대하여 몇 가지 사례를 제시하고 음미하여 보았다. 즉 문제 해결의 기본이 되는 사고로서 요구되는 정형문제의 해결을 위한 연산과 식의 지도에서 필요한 기본적 사고 형식과 모델설정 방안에 관하여 연구하였다.

노인 대퇴경부골절의 합병증과 그 대책

이창주 대한의학협회 1990 대한의학협회지 Vol.33 No.10

수은 폭로 정지후 근로자의 요중 수은 배설에 관한 추적 조사 연구

이창주,김광종,차철환 고려대학교 의과대학 1993 고려대 의대 잡지 Vol.30 No.1

The objective of this study was to estimate the biological half time and urinary mercury excretion rate constant of 20 workers with their urinary mercury concentrations repeatedly exceeded 200 ug/l before quiting exposure among the workers exposed to mercury vapor, making a centain fluorescent lamp manufacturing factory. This goal was approached by using their individual difference in excretion rate after quiting exposure. The results are as follows ; 1. The mean age of 20 workers was 27.4 age (20-51 age) and average duration of exposure was 2.8 years (1.2-5.8 years), the post exposure observation period was mean values of 134 days (78-269 days). 2. The average excretion rate constant of mercury in urine was 0.0123/day (0.0054-0.0205/day) and it proved that the excretion rate constant was high in the growps whose first urinary mercury concentration was high. 3. The average half times of urinary mercury turned out to be 64days (34-128 days) and half-times was short in the growps whose first urinary mercury concentration was high. 4. Significant negative correlation was found between urinary mercury concentration and days (r=-0.844 to -0.999, p<0.05) after qaiting exposure to mercury in 17 workers, among mercury workers.

Flavonoid-loaded liposomes to enhance antioxidation activity and skin penetration

이창주,나건 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Reactive oxygen species (ROS) cause oxidative stress related to aging and cancer. Skin is frontal tissue that faces ultraviolet light directly, so antioxidant treatment is essential. Flavonoids are an effective antioxidant, however, the stability and skin penetration aren’t enough to protect skin effectively. In this regard, we fabricated liposomal formulation to enhance stability, antioxidation and skin penetration. A non-ionic surfactant was used to stabilize liposome and enhance skin penetration. The formulation was optimized with various lipids, preparation methods and evaluated by live-cell ROS detection assay, Franz diffusion cell. The remote loading method with fully-saturated phospholipids showed the highest loading contents of flavonoid, stability of formulation and antioxidation activity with high skin penetration. The cytotoxicity of liposome was negligible in vitro test. Therefore, new formulation of flavonoid represents a promising platform for pharmaco-cosmetic industry.

Tumor-target magnetic nanoparticles for simultaneous imaging and therapy with photosensitizer

이창주,김경섭,나건 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

An elaborate diagnosis of tumor has been studied with the concept of theranostic, for effective tumor therapy. Among which, photosensitizer (PS) is considered because PS has powerful reactive oxygen species (ROS) generation capacity, fluorescence so it can diagnosis and therapy simultaneously. Also, superparamagnetic iron oxide nanoparticles (SPIONs) have been developed with the similar reason of PS. However, PS and SPIONs have some limitations such as low solubility, absence of target ability. We fabricated monocarboxylic acid coated magnetic nanoparticles(MCMNs), with PS and polyethylene glycol linker to overcome these limitations. MCMNs preserve MRI contrast and fluorescence evaluated by relaxation test and confocal laser scanning measurement. MCMNs shows selective internalization aspect to tumor cell in our system. The cytotoxicity of MCMNs controlled under a laser irradiation. These results indicate MCMNs can be a potential theranositc tumor therapy agents.