Exosome Isolation Technology Using Chitosan-coated Magnetic Nanoparticles

Chiyeon SONG,Jihye KIM,Heewon AN,Hyewon KIM,Sojin SHIN,Sang Hoon LEE,Jung Taek KANG,Hyun-Ouk KIM 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10

Exosomes, a type of extracellular vesicles (EVs), contain protein complexes, DNA and RNA, so exosomes can be used as crucial factors in liquid biopsies. The roles of exosomes in cell-to-cell signaling and specific targeting are being actively studied worldwide. For using exosomes, however, the current exosome-isolation technologies have some limitations such as low purity, high cost, time- and labor-intensive. In this research, we suggest chitosan coated magnetic nanoparticles (CMNPs) to capture exosome efficiently. Because CMNPs are positively charged, they attract the negatively charged exosomes by electrostatic reaction. The exosomes/CMNPs clusters were separated from cell culture and exosomes were isolated by adding elution buffer solution. Then, the CMNPs were collected and reused. The CMNPs were characterized by DLS, FTIR, ELS, and TEM and the capture-efficiency was determined NTA and western blotting. Compared with the traditional method and commercial kit, we confirmed that our method is superior in purity, yield, cost, and economical efficiency. With this technique, exosomes can be simply captured and used for clinical research.

이동 컴퓨팅 환경에서 타임스탬프를 이용한 트랜잭션 스케줄링

김치연(Chiyeon Kim),황부현(Buhyun Hwang) 한국정보과학회 1999 정보과학회논문지(B) Vol.26 No.1

이동 컴퓨팅 환경에서 이동 호스트는 무선 망의 제한된 대역폭을 효율적으로 사용하기 위하여 캐쉬를 사용한다. 지금까지 제안된 캐쉬 관리 방법에서의 문제점은 캐쉬에서 필요한 데이타를 즉각적으로 캐쉬하였을 때 이동 트랜잭션의 직렬성이 위배될 수 있다는 것이다. 또한 서버와 이동 호스트에서 수행되는 트랜잭션의 올바른 수행을 위해서는 스케줄링 방법을 필요로 하는데, 아직까지는 이동 컴퓨팅 환경에서의 트랜잭션 스케줄링 방법을 다룬 연구들이 많지 않다. 그 중 록을 이용한 스케줄링 방법에서는 트랜잭션의 스케줄링을 위하여 서버와 이동 호스트 사이에서 부가적인 메시지 교환을 필요로 하고, 교착상태가 발생할 수 있다는 문제점이 있다. 본 논문에서는 캐쉬를 사용하는 이동 컴퓨팅 환경에 적합한 트랜잭션의 스케줄링 방법에 대하여 제안한다. 제안한 방법은 록을 사용한 방법에서 발생하는 부가적인 메시지 교환을 줄이기 위해 타임스탬프를 이용하며, 서버에 다중버전을 유지함으로써 늦게 제출된 이동 트랜잭션이나 장기간에 걸쳐 수행되는 이동 트랜잭션의 완료율을 향상시킬 수 있다. 또한 이동 호스트의 타임스탬프에 따라 버전을 접근할 수 있게 하여 즉각적인 캐슁으로 인하여 발생할 수 있는 문제점을 해결하고, 수행되는 트랜잭션의 직렬가능한 수행을 보장한다. A mobile host in mobile computing environments uses a cache to effectively use the narrow bandwidth of the wireless network. The problem in the cache management methods proposed until now is that the serializability of mobile transactions may be destroyed when a mobile host immediately caches the data from a server. A scheduling method is needed for the correct execution for transactions that are executed in the mobile hosts and the servers, but the studies for scheduling them are rarely done. In the scheduling method that uses the lock, additional message exchanges are needed to schedule the transactions and a deadlock may occur. In this paper, we propose an efficient transaction scheduling method suitable to the mobile computing environments when a mobile host uses a cache. The proposed method uses the timestamp to reduce the additional message exchange in the locking method, and it maintains the multiversion in the server for increasing the commit ratio of the too late mobile transactions and the long duration transactions. Since mobile transactions can access a suitable version using their timestamp, the problem due to the immediate caching can be resolved while maintaining the serializable execution of the transactions.

3단계 스케쥴링 모델에서 회복기법에 관한 연구

김치연(Chiyeon Kim),윤현윤(Hyunyun Yun),황부현(Buhyun Hwang) 한국정보과학회 1993 한국정보과학회 학술발표논문집 Vol.20 No.1

MDBS에서 여러 가지 유형의 고장이 발생되면, 회복 관리자는 데이타베이스의 상태를 고장이 발생되기 전의 일관성있는 상태로 복구하여야 한다. 본 연구에서는 3단계스케쥴링 모델에 적합한 회복 알고리즘을 제안한다. 제안된 회복 방법은 전역적으로 완료되었으나 고장으로 인하여 지역 데이타베이스 시스템에서 철회된 부트랜잭션의 결과를 반영하는 재수행 방법을 이용한다. 또한, 제안된 회복 방법은 일반적으로 재수행 방법의 사용시 발생할 수 있는 전역적 직렬성 파괴의 문제점을 해결하고, 지역 자치성을 제약하지 않는 효율적인 회복 방법이다.

P001 : A clinical analysis of skin disease in the western gyeongnam province of the elderly

( Seokrim Kim ),( Yun Sun Moon ),( Do Seon Jeong ),( Dong Hwa Park ),( Chiyeon Kim ),( Taejin Yoon ) 대한피부과학회 2014 대한피부과학회 학술발표대회집 Vol.66 No.2

Background: With the advancement of socioeconomic and medical sciences, the number of elderly patients with skin diseases significantly increased. Objectives: The purpose of this study was to evaluate the prevalence of dermatologic diseases in elderly patients and to compare the results with the previous reports in malignant and benign skin tumors. Methods: We retrospectively reviewed 2,678 outpatients over 65 years of age, who visited the Department of Dermatology from January 2010 to December 2013. We compared the clinical diagnoses and analyzed the distribution of dermatologic diseases and clinical features, including the factors of age and sex. Results: The incidence in the group of age over 65 years was 15.6%(2,678). The ratio of male to female was 1:1.13(1,257:1,421). The type of skin diseases in the group were as follows: infectious skin disease(26.1%); eczema(23.2%); epidermal and adnexal nevi and tumors(17.5%); drug eruption, erythema, and urticaria(7.0%); pruritus, psychocutaneous disorder, and neurocutaneous dermatoses(6.6%); papulosquamous disease(3.3%); diseases of the skin appendages(3.2%); disorders of pigmentation(2.5%); diseases of the mucous membrane(2.3%); cutaneous vascular diseases(2.2%); and skin tumors (21.5%). The most common malignant tumors was squamous cell carcinoma(33.9). The most common benign tumors was actinic keratosis(48.0%). Conclusion: This study provides useful data on the incidence and the characteristics of elderly skin diseases.

<i>Gentiana scabra</i> Bunge roots alleviates skin lesions of contact dermatitis in mice

Yang, Beodeul,Kim, Sura,Kim, Jung-Hoon,Lim, Chiyeon,Kim, Hyungwoo,Cho, Suin Elsevier 2019 Journal of Ethnopharmacology Vol.233 No.-

<P><B>Abstract</B></P> <P><B>Ethnopharmacological relevance</B></P> <P>The roots and rhizomes of <I>Gentiana scabra</I> Bunge in the family Gentianaceae comprise a major herbal medicine for skin diseases caused by wind-heat or dampness-heat in China, Japan and Korea. This treatment can clear away heat and dry dampness and purge fire from the liver and gallbladder.</P> <P><B>Aim of the study</B></P> <P>This study was designed to investigate the therapeutic potential and anti-inflammatory effects of <I>G. scabra</I>, roots and rhizomes.</P> <P><B>Materials and methods</B></P> <P>Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) revealed the presence of gentiopicrin in the roots and rhizomes of <I>G. scabra</I>. We then investigated the effects of ethanol extract of <I>G. scabra</I>, roots and rhizomes (EEGS) on skin lesions and thickness, erythema and melanin index, histopathological abnormalities, and cytokine and chemokine production in mice with contact dermatitis (CD) induced by 1-fluoro-2,4-dinitrofluorobenzene (DNFB). Moreover, the effects of EEGS on body weights and spleen body weight ratio were evaluated.</P> <P><B>Results</B></P> <P>Topical application of EEGS alleviated skin lesions such as surface roughness, excoriations and scabs on the skin of CD mice, as well as prevented skin enlargement, and lowered the erythema and melanin index. In addition, EEGS prevented hyperkeratosis, epidermal hyperplasia and immune cell infiltration, and inhibited TNF-α, IFN-γ, IL-6 and MCP-1 production in inflamed tissues. EEGS did not affect changes in body weights and spleen body weight ratio in contrast to dexamethasone.</P> <P><B>Conclusions</B></P> <P>These data indicate that the roots and rhizomes of <I>G. scabra</I> can be used as anti-inflammatory agents for CD with relative safety and that its therapeutic mechanisms are related to regulation of pro-inflammatory cytokines such as TNF-α and IFN-γ.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Anti-inflammatory Effects of <i>Brassica oleracea</i> Var. capitata L. (Cabbage) Methanol Extract in Mice with Contact Dermatitis

Lee, Youjung,Kim, Seoyoung,Yang, Beodeul,Lim, Chiyeon,Kim, Jung-Hoon,Kim, Hyungwoo,Cho, Suin Medknow PublicationsMedia Pvt Ltd 2018 Pharmacognosy magazine Vol.14 No.54

<P><B>Background:</B></P><P>Cabbage, <I>Brassica oleracea</I> var. capitata L., is one of the most common vegetables in the world. Because of its high levels of flavonoids and anthocyanins, cabbage has long been used as a herbal medicine. The antioxidant and anti-inflammatory properties of cabbage were also recently been reported.</P><P><B>Objective:</B></P><P>This study was designed to investigate the anti-inflammatory effects of cabbage in mice with contact dermatitis (CD).</P><P><B>Materials and Methods:</B></P><P>We investigated the effects of methanol extract of <I>B. oleracea</I> var. capitata L. (MEBO) on ear swelling, erythema, and histopathological changes in CD mice. Moreover, the effects on cytokine production and the spleen/body weight ratio were investigated.</P><P><B>Results:</B></P><P>Topical treatment with MEBO inhibited ear swelling and erythema significantly. MEBO also significantly inhibited epidermal hyperplasia and infiltration of immune cells. Furthermore, the levels of tumor necrosis factor-alpha, interferon-gamma, interleukin-6, and monocyte chemotactic protein-1 in inflamed tissues were effectively lowered by MEBO. Finally, MEBO did not affect body weight gain or spleen body weight ratio.</P><P><B>Conclusions:</B></P><P>These results indicate that cabbage can be used for the treatment of skin inflammation and that its anti-inflammatory activity is closely related to the inhibition of Th1 skewing reactions.</P><P><B>SUMMARY</B></P><P><P>MEBO inhibited ear thickness, weight, and erythema in inflamed skin</P><P>MEBO also prevented epidermal hyperplasia and infiltration of immune cells</P><P>The levels of tumor necrosis factor-α, interferon-γ, interleukin-6, and monocyte chemotactic protein-1 in inflamed tissues were lowered by MEBO.</P></P> >[FIG OMISSION]</BR><P><B>Abbreviations used:</B> AOO: Acetone and olive oil (4:1), CBA: Cytometric bead array, CD: Contact dermatitis, DEX: Dexamethasone, DNFB: 1-fluoro-2,4-dinitrofluorobenzene, GM-CSF: Granulocyte-macrophage colony-stimulating factor, ICAM-1: Intercellular Adhesion Molecule-1, LPS: Lipopolysaccharide, MEBO: Methanol extract of <I>Brassica oleracea</I>, MCP-1: Monocyte chemotactic protein-1, NO: Nitric oxide.</P>

Compensation of a Squint Free Phased Array Antenna System using Artificial Neural Networks

Kim, Young-Ki,Jeon, Do-Hong,Park, Chiyeon Korean Institute of Intelligent Systems 2004 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.4 No.2

This paper describes an advanced compensation for non-linear functions designed to remove steering aberrations from phased array antennas. This system alters the steering command applied to the antenna in a way that the appropriate angle commands are given to the array steering software for the antenna to point to the desired position instead of squinting. Artificial neural networks are used to develop the inverse function necessary to correct the aberration. Also a straightforward antenna steering function is implemented with neural networks for the 9-term polynomials of forward steering function. In all cases the aberration is removed resulting in small RMS angular errors across the operational angle space when the actual antenna position is compared with the desired position. The use of neural network model provides a method of producing a non-linear system that can correct antenna performance and demonstrates the feasibility of generating an inverse steering algorithm.

Optimal Burn-In under Warranty

Kuinam J. Kim,Chiyeon Park,Changeui Hong 대한안전경영과학회 1999 대한안전경영과학회 학술대회논문집 Vol.1999 No.1

Optimal Burn-In under Warranty

Kuinam J. Kim,Chiyeon Park,Changeui Hong 대한안전경영과학회 1999 대한안전경영과학회 학술대회논문집 Vol.1999 No.11

This paper discusses an optimal burn-in procedure to minimize total costs based on the assumption that the failure rate pattern follows a bimodal mixed Weibull distribution. The procedure will consider warranty period as a factor of the total expected burn-in cost. A cost model is formulated to find the optimal burn-in time that minimizes the expected burn-in cost. Conditional reliability for warranty period will be discussed. An illustrative example is included to show how to use the cost model in practice.

Compensation of a Squint Free Phased Array Antenna System using Artificial Neural Networks

Young-Ki Kim,Do-Hong Jeon,Chiyeon Park 한국지능시스템학회 2004 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.4 No.2

This paper describes an advanced compensation for non-linear functions designed to remove steering aberrations from phased array antennas. This system alters the steering command applied to the antenna in a way that the appropriate angle commands are given to the array steering software for the antenna to point to the desired position instead of squinting. Artificial neural networks are used to develop the inverse function necessary to correct the aberration. Also a straightforward antenna steering function is implemented with neural networks for the 9-term polynomials of forward steering function. In all cases the aberration is removed resulting in small RMS angular errors across the operational angle space when the actual antenna position is compared with the desired position. The use of neural network model provides a method of producing a non-linear system that can correct antenna performance and demonstrates the feasibility of generating an inverse steering algorithm.