http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Youngkyung Ko (검색결과 31 건)
- 무료
- 기관 내 무료
- 유료
-
Ko, Youngkyung,Lee, Eun-Mi,Park, Joo Cheol,Gu, Man Bock,Bak, Seongmin,Ji, Suk Korean Academy of Periodontology 2020 Journal of Periodontal & Implant Science Vol.50 No.3
Purpose: The aims of this study were to examine the salivary microbiota in conditions of periodontal health and disease and to explore microbial changes following nonsurgical periodontal treatment. Methods: Non-stimulated saliva samples were collected from 4 periodontally healthy participants at baseline and from 8 patients with chronic periodontitis at baseline and 3 months following nonsurgical periodontal therapy. The V3 and V4 regions of the 16S rRNA gene from the DNA of saliva samples were amplified and sequenced. The salivary microbial compositions of the healthy participants and patients with periodontitis prior to and following nonsurgical treatment of periodontitis were compared based on the relative abundance of various taxa. Results: On average, 299 operational taxonomic units were identified in each sample. The phylogenetic diversity in patients with periodontitis was higher than that in healthy participants and decreased following treatment. The abundance of the phylum Spirochaetes and the genus Treponema in patients with periodontitis was 143- and 134-fold higher than in the healthy control group, respectively, but decreased significantly following treatment. The species that were overabundant in the saliva of patients with periodontitis included the Peptostreptococcus stomatis group, Porphyromonas gingivalis, the Fusobacterium nucleatum group, Parvimonas micra, Porphyromonas endodontalis, Filifactor alocis, and Tannerella forsythia. The phylum Actinobacteria, the genus Streptococcaceae_uc, and the species Streptococcus salivarius group were more abundant in healthy participants than in those with periodontitis. There was a trend toward a decrease in disease-associated taxa and an increase in health-associated taxa following treatment. Conclusions: Our results revealed differences in the taxa of salivary microbiota between conditions of periodontal health and disease. The taxa found to be associated with health or disease have potential for use as salivary biomarkers for periodontal health or disease.
-
-
Youngkyung Kim,Eun-hye Kim,Kyu Sang Lee,Koeun Lee,Sung Ho Park,Sook Hyun Na,Cheolwoong Ko,Junesun Kim,Young Wook Yooon 대한생리학회-대한약리학회 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.1
This study was performed to investigate whether an intra-articular injection of transient receptor potential vanilloid 1 (TRPV1) receptor agonist, resiniferatoxin (RTX) would alleviate behavioral signs of arthritic pain in a rat model of osteoarthritis (OA). We also sought to determine the effect of RTX treatment on calcitonin gene-related peptide (CGRP) expression in the spinal cord. Knee joint inflammation was induced by intra-articular injection of monosodium iodoacetate (MIA, 8 mg/50 µl) and weight bearing percentage on right and left hindpaws during walking, paw withdrawal threshold to mechanical stimulation, and paw withdrawal latency to heat were measured to evaluate pain behavior. Intra-articular administration of RTX (0.03, 0.003 and 0.0003%) at 2 weeks after the induction of knee joint inflammation significantly improved reduction of weight bearing on the ipsilateral hindlimb and increased paw withdrawal sensitivity to mechanical and heat stimuli. The reduction of pain behavior persisted for 3~10 days according to each behavioral test. The MIA-induced increase in CGRP immunoreactivity in the spinal cord was decreased by RTX treatment in a dose-dependent manner. The present study demonstrated that a single intra-articular administration of RTX reduced pain behaviors for a relatively long time in an experimental model of OA and could normalize OA-associated changes in peptide expression in the spinal cord.
-
Kim, Youngkyung,Kim, Eun-hye,Lee, Kyu Sang,Lee, Koeun,Park, Sung Ho,Na, Sook Hyun,Ko, Cheolwoong,Kim, Junesun,Yooon, Young Wook The Korean Society of Pharmacology 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.1
This study was performed to investigate whether an intra-articular injection of transient receptor potential vanilloid 1 (TRPV1) receptor agonist, resiniferatoxin (RTX) would alleviate behavioral signs of arthritic pain in a rat model of osteoarthritis (OA). We also sought to determine the effect of RTX treatment on calcitonin gene-related peptide (CGRP) expression in the spinal cord. Knee joint inflammation was induced by intra-articular injection of monosodium iodoacetate (MIA, $8mg/50{\mu}l$) and weight bearing percentage on right and left hindpaws during walking, paw withdrawal threshold to mechanical stimulation, and paw withdrawal latency to heat were measured to evaluate pain behavior. Intra-articular administration of RTX (0.03, 0.003 and 0.0003%) at 2 weeks after the induction of knee joint inflammation significantly improved reduction of weight bearing on the ipsilateral hindlimb and increased paw withdrawal sensitivity to mechanical and heat stimuli. The reduction of pain behavior persisted for 3~10 days according to each behavioral test. The MIA-induced increase in CGRP immunoreactivity in the spinal cord was decreased by RTX treatment in a dose-dependent manner. The present study demonstrated that a single intra-articular administration of RTX reduced pain behaviors for a relatively long time in an experimental model of OA and could normalize OA-associated changes in peptide expression in the spinal cord.
-
Han, Kyungdo,Ko, Youngkyung,Park, Yong Gyu,Park, Jun-Beom Williams & Wilkins Co 2016 Medicine Vol.95 No.6
<P><B>Abstract</B></P><P>The association between menstrual cycle irregularities and system disease has been evaluated in previous studies. However, the association between periodontal disease and menstrual cycle irregularity has not been fully investigated. The study aimed to evaluate the relationship between periodontal disease and tooth loss in women before menopause and menstrual cycle irregularity using nationally representative data.</P><P>This study performed a cross-sectional analysis and used hierarchical multivariable logistic regression analysis models. Data from Korean National Health and Nutrition Examination Survey (KNHANES) between 2010 and 2012 were analyzed. The analysis in this study was confined to a total of 1553 respondents over 19 years old who had not gone through menopause and had no missing values for the reproductive factors and outcome variables. A community periodontal index was greater than or equal to code 3 was used to define periodontal treatment needs.</P><P>The risk of periodontal treatment needs tended to increase in the presence of menstrual cycle irregularity after adjustment for potential confounders (<I>P</I> for trend in the odds ratios = .0481 in model 1; 0.0613 in model 2; 0.0369 in model 3; 0.0456 in model 4). The number of natural teeth of 28 did not reach statistically significant differences (<I>P</I> for trend in the odds ratios = 0.2204 in model 1; 0.2373 in model 2; 0.2814 in model 3; 0.2609 in model 4).</P><P>Menstrual cycle irregularity was positively associated with the risk of periodontal treatment needs in Korean women before menopause. However, there was no significant association between tooth loss and menstrual cycle irregularity. Menstrual cycle irregularity may be considered to be a potential risk indicator for periodontal treatment needs in Korean women before menopause.</P>
-
고찬영(Chanyoung Ko),이영경(Youngkyung Lee),이광수(Kwangsu Lee),박종환(Jong Hwan Park) 한국정보보호학회 2021 정보보호학회논문지 Vol.31 No.3
최근 양자 컴퓨터의 개발이 가속화되면서 기존 인터넷 환경에서 사용되고 있는 인수분해 및 이산대수 기반의 전자서명 기법들의 안전성에 대한 문제가 제기되고 있다. 이에 대응하기 위해 미국 국립표준기술연구원(NIST)의 표준화 작업을 비롯하여 양자 컴퓨팅 환경에서 안전한 여러 가지 전자서명 기법들이 제시되고 있다. 본 논문에서는 2018년 Behnia 등이 CCS 컨퍼런스에서 발표한 TACHYON 전자서명 기법을 이용한 다중 서명 기법을 설계하여 제시하고, 안전성을 증명하고자 한다. 다중 서명 기법은 최근 많은 관심을 받고 있는 암호화폐 분야에서 전자지갑의 개인키 의존도를 분산하여 보다 안전한 전자지갑 시스템을 구성할 수 있는 핵심 기술로, 최근 많은 연구자들과 개발자들이 관심을 갖고 있는 전자서명 응용 분야이다. 본 논문에서 제시하는 다중 서명 기법은 일반 공개키 모델(plain public key model)에서 공개키 결합(public key aggregation)이 가능한 기법으로, 부가적인 영지식 증명(zero-knowledge proof) 기법이 필요하지 않으며, 결합 된 단일 공개키만으로 효율적인 시스템을 구성할 수 있는 기법이다. Recently, the acceleration of the development of quantum computers has raised the issue of the safety of factorization and discrete logarithm based digital signature schemes used in existing Internet environments. To solve the issue, several digital signature schemes are presented that are safe in post-quantum computing environments, including standardization work by the National Institute of Standards and Technology(NIST). In this paper, we design and present a multi-signature scheme based on the TACHYON announced by Behnia et al. in 2018 CCS conference, and prove the security. Multi-signature schemes are key techniques that can distribute the dependence of cryptocurrency-wallet on private keys in the cryptocurrency field, which has recently received much attention as an digital signature application, and many researchers and developers have recently been interested. The multi-signature scheme presented in this paper enables public key aggregation in a plain public key model, which does not require additional zero-knowledge proof, and can construct an effective scheme with only an aggregated public key.
-
Lee, Sung-Il,Ko, Youngkyung,Park, Jun-Beom D.A. Spandidos 2017 Experimental and therapeutic medicine Vol.13 No.5
<P>Gingiva-derived stem cells have been applied for tissue-engineering purposes and may be considered a favorable source of mesenchymal stem cells as harvesting stem cells from the mandible or maxilla may be performed with ease under local anesthesia. The present study was performed to fabricate stem-cell spheroids using concave microwells and to evaluate the maintenance of stemness, viability, and differentiation potential. Gingiva-derived stem cells were isolated, and the stem cells of 4×10<SUP>5</SUP> (group A) or 8×10<SUP>5</SUP> (group B) cells were seeded into polydimethylsiloxane-based, concave micromolds with 600 µm diameters. The morphology of the microspheres and the change of the diameters of the spheroids were evaluated. The viability of spheroids was qualitatively analyzed via Live/Dead kit assay. A cell viability analysis was performed on days 1, 3, 6, and 12 with Cell Counting Kit-8. The maintenance of stemness was evaluated with immunocytochemical staining using SSEA-4, TRA-1-60(R) (positive markers), and SSEA-1 (negative marker). Osteogenic, adipogenic, and chondrogenic differentiation potential was evaluated by incubating spheroids in osteogenic, adipogenic and chondrogenic induction medium, respectively. The gingiva-derived stem cells formed spheroids in the concave microwells. The diameters of the spheroids were larger in group A than in group B. The majority of cells in the spheroids emitted green fluorescence, indicating the presence of live cells at day 6. At day 12, the majority of cells in the spheroids emitted green fluorescence, and a small portion of red fluorescence was also noted, which indicated the presence of dead cells. The spheroids were positive for the stem-cell markers SSEA-4 and TRA-1-60(R) and were negative for SSEA-1, suggesting that these spheroids primarily contained undifferentiated human stem cells. Osteogenic, adipogenic, and chondrogenic differentiation was more evident with an increase of incubation time: Mineralized extracellular deposits were observed following Alizarin Red S staining at days 14 and 21; oil globules were increased at day 18 when compared with day 6; and Alcian blue staining was more evident at day 18 when compared with day 6. Within the limits of this study, stem-cell spheroids from gingival cells maintained the stemness, viability, and differentiation potential during the experimental periods. This method may be applied for a promising strategy for stem-cell therapy.</P>
-
Financing through Stock Market in Emerging Economy : Do They Lead to Real Investments?
Hasung Jang,Woojin Kim,YoungKyung Ko 한국재무학회 2009 한국재무학회 학술대회 Vol.2009 No.11
This paper evaluates the principal role of a stock market in efficiently allocating resources in an emerging economy. Using a sample of 900 follow-on primary common stock offerings made by Korean publicly traded firms during 2000 to 2007, we find that half of the proceeds are raised through private placements made to creditor banks through debt-equity swaps. Moreover, more than a third of the proceeds raised through public offerings are used to increase equity investments in other (affiliated) firms. We also find that equity issuing firms are generally in bad financial conditions and more likely to get delisted subsequent to the issue especially during the earlier part of the sample period. These findings suggest that the key role of new equities in these markets may be to recapitalize the existing investments or to reshape the overall control structure of a business group in response to external government regulations rather than to finance new real investments.
-
-
Lee, Sung-Il,Ko, Youngkyung,Park, Jun-Beom D.A. Spandidos 2017 Experimental and therapeutic medicine Vol.13 No.6
<P>The present study was performed to create stem cell spheroids from human gingiva-derived stem cells and osteoprecursor cells and to evaluate the maintenance of the stemness, the viability and osteogenic differentiation of the cell spheroids. Gingiva-derived stem cells were isolated, and a total of 6×10<SUP>5</SUP> stem cells and osteoprecursor cells were seeded into concave micromolds at various ratios. Gingiva-derived stem cells and/or osteoprecursor cells formed spheroids in concave microwells. The spheroids demonstrated a smaller diameter when the number of osteoprecursor cells seeded was lower. The majority of cells in the spheroids were identified to be live cells and the cell spheroids preserved viability throughout the experimental period. The cell spheroids, which contained stem cells, were positive for stem-cell markers. Cell spheroids in concave microwells demonstrated a statistically significant increase in alkaline phosphatase activity as time progressed (P<0.05). A statistically significant difference in phosphatase activity was observed in the stem cell alone group when compared with the osteoprecursor cell group at day 5 (P<0.05). Mineralized extracellular deposits were observed in each group after Alizarin Red S staining. Within the limits of the present study, cell spheroids from gingival cells and osteoprecursor cells maintained shape, viability, stemness and osteogenic differentiation potential.</P>
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
