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      • KCI등재후보

        Enhancement of radiation effect using beta-lapachone and underlying mechanism

        안기정,이형식,배세경,송창원 대한방사선종양학회 2013 Radiation Oncology Journal Vol.31 No.2

        Beta-lapachone (β-Lap; 3,4-dihydro-2, 2-dimethyl-2H-naphthol[1, 2-b]pyran-5,6-dione) is a novel anti-cancer drug under phase I/II clinical trials. β-Lap has been demonstrated to cause apoptotic and necrotic death in a variety of human cancer cells in vitro and in vivo. The mechanisms underlying the β-Lap toxicity against cancer cells has been controversial. The most recent view is that β-Lap, which is a quinone compound, undergoes two-electron reduction to hydroquinone form utilizing NAD(P)H or NADH as electron source. This two-electron reduction of β-Lap is mediated by NAD(P)H:quinone oxidoreductase (NQO1), which is known to mediate the reduction of many quinone compounds. The hydroquinone forms of β-Lap then spontaneously oxidizes back to the original oxidized β-Lap, creating futile cycling between the oxidized and reduced forms of β-Lap. It is proposed that the futile recycling between oxidized and reduced forms of β-Lap leads to two distinct cell death pathways. First one is that the two-electron reduced β-Lap is converted first to one-electron reduced β-Lap, i.e., semiquinone β-Lap (SQ)ㆍ- causing production of reactive oxygen species (ROS), which then causes apoptotic cell death. The second mechanism is that severe depletion of NAD(P)H and NADH as a result of futile cycling between the quinone and hydroquinone forms of β-Lap causes severe disturbance in cellular metabolism leading to apoptosis and necrosis. The relative importance of the aforementioned two mechanisms, i.e., generation of ROS or depletion of NAD(P)H/NADH, may vary depending on cell type and environment. Importantly, the NQO1 level in cancer cells has been found to be higher than that in normal cells indicating that β-Lap may be preferentially toxic to cancer cells relative to non-cancer cells. The cellular level of NQO1 has been found to be significantly increased by divergent physical and chemical stresses including ionizing radiation. Recent reports clearly demonstrated that β-Lap and ionizing radiation kill cancer cells in a synergistic manner. Indications are that irradiation of cancer cells causes long-lasting elevation of NQO1, thereby sensitizing the cells to β-Lap. In addition, β-Lap has been shown to inhibit the repair of sublethal radiation damage. Treating experimental tumors growing in the legs of mice with irradiation and intraperitoneal injection of β-Lap suppressed the growth of the tumors in a manner more than additive. Collectively, β-Lap is a potentially useful anti-cancer drug, particularly in combination with radiotherapy.

      • KCI등재

        외국인 유학생들의 학술적 글쓰기 막힘 개선 방안 연구

        안기정 한국외국어대학교 외국어교육연구소 2020 외국어교육연구 Vol.34 No.3

        This study explores the difficulty that international students face when writing academic papers, after investigating the nature of the writing block that international students experience, we prepared a systematic method to combat the factors leading to this issue. The research involved administering a questionnaire of writing block and conducting a case study on international students; the results were collected and used to diagnose the following problems: First, among the sub-factors of comprehension, interpretation of meaning, the assigned task, and the environment, the following were shown to have the most statistically significant impact on writing block: text understanding and content creation, content structure, writing anxiety and negative attitude, writing efficacy, evaluation of the task, environment in which the task is done, and lack of academic writing knowledge. However, the influence that each of these factors has on writing block is somewhat different. Second, each factor that contributes to writing block does not exist independently but interacts with the other factors to either strengthen or weaken the writing block. Third, the students identified writing block as any time that they were unable to progress in their writing due to either lack of necessary knowledge or difficulty using a second language. Fourth, although the support of the community is necessary for international students in an academic writing course, the community is not established in a way that effectively provides this support. Therefore, it is necessary to introduce effective assistance measures that reflect the individual differences between students. Based on the diagnosis of the problem, four methods were designed to help international students struggling with writing block. These methods include: supporting students struggling with comprehension problems, helping students control problems that occur at the emotional level, correcting repeated errors students make in regards to the kinds of expressions used in used in different writing genres, and recognizing the problems students have in academic writing as well as the causes of these problems. 본 연구에서는 외국인 유학생들이 학술적 글쓰기 과정에서 직면하는 어려움으로 인해 쓰기가 원만하게 진행되지 못하는 쓰기 막힘(writing block) 현상에 접근하여, 학술적 글쓰기 막힘의 본질을 탐색한 후, 쓰기 막힘을 발생시키는 요인들을 해결하기 위한 체계적인 방안을 마련하였다. 연구를 위해 외국인 유학생들을 대상으로 쓰기 막힘 설문조사와 사례연구를 실시하였으며, 결과를 종합하여 다음과 같은 문제점이 진단되었다. 첫째, 쓰기 막힘에 통계적으로 유의미하게 영향을 미치는 요인은 인지․정의․과제․환경 요인의 하위 요인 중 ‘텍스트 이해 및 내용 생성, 내용 조직, 쓰기 불안 및 부정적 태도, 쓰기 효능감, 과제 평가, 과제 환경, 학술적 글쓰기 지식 부족’ 등으로 나타났다. 단, 각 요인들이 쓰기 막힘에 미치는 영향력은 다소 차이를 보인다. 둘째, 쓰기 막힘을 발생시키는 각 요인들은 독립적으로 존재하지 않고 상호작용하여 쓰기 막힘 문제를 강화시키기도 하고 완화시키기도 한다. 셋째, 유학생들은 학술적 글쓰기 과정에 필요한 지식 부족과 제2 언어 사용 등의 어려움으로 인해 쓰기가 진행되지 못하는 모든 순간을 쓰기 막힘으로 인식하고 있는 것으로 드러났다. 넷째, 유학생들의 학술적 글쓰기 과정에서 공동체의 조력이 필수적이지만 현재 공동체의 조력은 효과적인 방향으로 이루어지지 못하고 있으며, 유학생들의 개별 차를 반영한 효과적인 조력 방안이 필요하다. 문제점 진단을 바탕으로 설계된 쓰기 막힘 해결 방안은 쓰기 막힘을 유발하는 인지적 영역에서 부족한 부분을 지원하는 방안, 유학생의 정서적 차원에서 발생하는 문제를 조절할 수 있는 방안, 장기 기억으로 이어지는 장르 표현 관련 오류 수정 방안, 유학생들이 스스로 자신의 학술적 글쓰기 막힘 상태와 막힘이 발생하는 원인을 인식할 수 있도록 하는 방안 등의 4가지로 마련하였다.

      • KCI등재

        Lymphovascular invasion as a negative prognostic factor for triple-negative breast cancer after surgery

        안기정,박지선,최윤선 대한방사선종양학회 2017 Radiation Oncology Journal Vol.35 No.4

        Purpose: This study aimed to evaluate the prognostic effects of lymphovascular invasion (LVI) in triple-negative breast cancer (TNBC) patients who underwent surgical resection. Materials and Methods: A total of 63 non-metastatic TNBC patients who underwent surgical resection were retrospectively investigated from 2007 to 2016 in Inje University Busan Paik Hospital. Pathological tests revealed that 12 patients (19.0%) had LVI. Approximately 61.9% (n = 39) of the patients’ samples stained positive for p53. Additional chemotherapy and radiotherapy (RT) were performed in 53 (84.1%) and 47 (74.6%) patients, respectively. Results: The median follow-up period was 39.5 months (range, 5.9 to 123.0 months). The pathological T stage (p = 0.008), N stage (p = 0.014), and p53 positivity (p = 0.044) were associated with LVI. Overall, the 3-year disease-free survival (DFS) rate and overall survival (OS) rate were 85.4% and 90.2%, respectively. Ten patients (15.9%) experienced relapse. LVI (n = 12) was associated with relapses (p = 0.016). p53 positivity was correlated with poor DFS (p = 0.048). Furthermore, LVI was related to poor DFS (p = 0.011) and OS (p = 0.001) and considered as an independent prognostic factor for DFS (p = 0.039). The 3-year DFS of patients with LVI (n = 12) was only 58.3%. Adjuvant RT minimized the negative prognostic effect of LVI on DFS (p = 0.068 [with RT] vs. p = 0.011 [without RT]). Conclusion: LVI was related to the detrimental effects of disease progression and survival of TNBC patients. Thus, a more effective treatment strategy is needed for TNBC patients with LVI.

      • KCI등재

        Checklist of the Staphylinidae (Coleoptera) in Korea

        안기정,조영복,김윤호,유인성,Alfred F. Newton 국립중앙과학관 2017 Journal of Asia-Pacific Biodiversity Vol.10 No.3

        A list of the 646 described species of Staphylinidae in Korea is presented. The list is in taxonomicsequence by subfamily, tribe, and genus and includes 215 genera in 55 tribes and 18 subfamilies. Weprovide the page reference of the original description of every species and genus listed, of many synonyms,and of all the Korean records. The list provides distribution of all the species by country (and forthe larger countries, by province or state). A brief taxonomic history of the Korean Staphylinidae ispresented. A complete bibliography is provided.

      • KCI등재

        비판적 담화 분석에 기초한 비판적 읽기-쓰기 통합 활동 실행 연구: 한국어 중급 학습자들을 대상으로

        안기정 한국외국어대학교 외국어교육연구소 2018 외국어교육연구 Vol.32 No.4

        This study aims to investigate (1) what kind of help intermediate learners of Korean received regarding an activity of newspaper article presentation, and (2) how their perspective about Korean texts changed, through integrated critical reading-writing instruction based on critical discourse analysis. During the integrated critical reading-writing activities, the learners had difficulties comprehending the critical reading-writing approach as well as Korean social issues. However, they ascertained that the activities led them to be more able to find a title of newspaper articles and questions for discussion and to express their opinions in public. Also, they citied that the activities provided them with the opportunities not only to raise their awareness on social problems of Korea but also to increase familiarity with a variety of Korean text genres. In conclusion, the integrated critical reading-writing activities based on critical discourse analysis had positive effects on intermediate learners of Korean in various aspects, and a need for further studies with learners of Korean for academic purposes is suggested. 이 연구는 비판적 담화 분석 이론을 기반으로 한 비판적 읽기-쓰기 통합수업을 통해 한국어 중급 학습자들이 신문 기사 발표 활동에 어떠한 도움을 받았는지, 한국어 텍스트에 대해 어떠한 인식의 변화가 있었는지 살펴보고자 한 연구이다. 학습자들은 비판적 읽기-쓰기 활동의 연습 과정에서 비판적 읽기 방법의 어려움을 느끼거나 한국의 사회적 문제에 대한이해의 어려움을 표현하기도 했으나, 이 활동을 통해 신문 기사 주제 찾기, 자신의 의견 발표하기, 토론 질문 찾기 등의 여러 과정에서 도움을받았다고 느꼈다. 뿐만 아니라 학습자들은 이 활동을 통해 사회 문제에대한 다양한 시각을 정립하게 되었고 여러 텍스트 장르에 대한 거리감을좁히는 등 다양한 직간접적인 효과를 경험하였다. 비판적 담화 분석에 기초한 비판적 읽기-쓰기 활동은 다양한 방면으로 학습자들에게 긍정적인영향을 미쳤으며, 이를 바탕으로 하여 향후 학문 목적 학습자를 대상으로하는 연구 등 다양한 후속 연구가 필요함을 제안하였다.

      • KCI등재

        흑마늘 가루 첨가 설기떡의 품질 특성 및 항산화 활성

        안기정 (사)한국조리학회 2021 한국조리학회지 Vol.27 No.7

        The proper ratio and quality characteristics of black garlic powder Sulgidduk were investigated. The physical properties of Sulgidduk, such as moisture content, color, texture DPPH radical scavenging activity, total polyphenol content, and Sensory characteristics preference such as color, flavor, texture, softness, and overall acceptability, were measured as follows. The moisture content decreased significantly as the level of black garlic powder added increased, and the Hunter's values showed a tendency of decreasing L and b values and increasing a value as the added level of black garlic powder increased. As a result of texture characteristics of black garlic powder Sulgidduk, the hardness decreased significantly as the added level increased. It was found that springiness, cohesiveness, and chewiness were also significantly reduced in all items. The level of total polyphenol contents was larger in the amount of black garlic powder added increased. The DPPH radical scavenging activity increased significantly as the amount of black garlic powder added increased, and the sensory characteristics preference results for color and softness increased significantly as the amount added increased. In this study, we intend to present basic data along with the optimal mixing ratio in order to maximize the use of black garlic powder containing antioxidants to utilize domestic agricultural products and to manufacture functional rice cakes with excellent sensory qualities.

      • SCOPUSKCI등재

        Nasopharyngeal Cancer in Patients Under Thirty Years of Age

        안기정,정은지,이형식,문성록,성진실,김귀언,서창옥,노준규,Ahn Ki Jung,Chang Eun Ji,Lee Hyung Sik,Moon Sun Rock,Seong Jin Sil,Kim Gwi Eon,Suh Chang Ok,Kyu John Juhn The Korean Society for Radiation Oncology 1990 Radiation Oncology Journal Vol.8 No.2

        비인강암은 해부학적으로 두개저부 및 중추신경계와 인접하고 있어 수술적 접근이 어렵고, 또 최근 항암제요법의 발달로 복합항암제를 이용한 항암제요법으로 반응율을 높이기 위한 여러 연구들이 진행되고 있지만, 아직까지 비인강암에 대한 치료는 방사선치료가 그 근간을 이루고 있다. 비인강암의 연령분포곡선은 30세 이후에 급격히 증가하여 45세에서 54세까지에서 수평을 이룬후 서서히 감소하는 곡선을 그리는데, 10대 내지 20대에서도 작은 증가곡선을 나타내어 bimodal curve를 그리게 된다. 30세 이전에 생긴 비인강암은 그 빈도가 매우 적어서 이에 대한 연구보고가 많지 않지만 일반적으로는 30세 이후에 생긴 비인강암과는 다른 임상양상을 보이는 것으로 보고되어 있다. 이에 저자들은 1971년부터 1987년까지 연세대학교 의과대학 치료방사선과에서 치료받았던 113명의 비인강암 환자들을 30세 이전과 30세 이후 환자군으로 구별하여, 임상적 특성 및 치료에 대한 관해율, 이에 따른 생존율 및 생존에 영향을 미치는 인자들, 그리고 치료실패양상 등을 분석 비교하여 향후 30세 이전의 비인강암 환자의 치료에 지침을 마련하고자 본 연구를 시행하여 다음과 같은 결과를 얻었다. 1. 30세 이전의 비인강암 환자에서 치료에 대한 초기반응율이 높았다 2. 30세 이전의 비인강암 환자에서 통계적 의의는 없었으나 원격전이가 많았다. 3. 두 연령군간에 생존율의 차이는 없었다. Between January 197l and December 1987, 113 patients with nasopharyngeal cancer (NPC) were treated by radiation therapy with or without chemotherapy in the department of Radiation Oncology, Yonsei University Hospital. There were 19 patients under thirty years of age. The histology was undifferentiated carcinoma in $68\%$ of the younger patients as compared to $47\%$ of the older patients. Sex, stage, initial symptoms and treatment modalities differed little from those of older patients. In younger patients, the initial complete response rate was $79\%$ as compared to older patients with $54\%$, distant metastases were more common and the overall five year survival rate was not significantly different between the two age groups ($33.7\%$ for the young vs. $37.4\%$ for the old). The five year survival rates for stage III and IV were $60.0\%$ and $24.5\%$, respectively. Histologic subtype was not correlated with survival. The best survival was found only in patients who obtained a complete clearance of disease after radiation therapy.

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