시료 희석 직접 주입 LC-MS/MS를 이용한 법화학 수용액 시료 중 카페인 신속 분석

최윤정,김희승,인문교,김진영,Choi, Yun Jeong,Kim, Hee Seung,In, Moon Kyo,Kim, Jin Young 대한약학회 2016 약학회지 Vol.60 No.3

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of caffeine in forensic aqueous sample. The centrifuged sample ($100{\mu}l$) was diluted 50-fold with distilled water. The diluted sample ($400{\mu}l$) was then diluted further with $200{\mu}l$ of 0.1% formic acid solution and $400{\mu}l$ of acetonitrile containing 500 ng of caffeine-(3-methyl-$^{13}C_3$) prior to LC-MS/MS analysis. The mobile phase was composed of 0.1% formic acid in distilled water (A) and acetonitrile (B). Chromatographic separation was performed by using a Zorbax SB-C18 ($100mm{\times}2.1mm$ i.d., $3.5{\mu}m$) column and caffeine was eluted within 1.1 min. Linear least-squares regression with a 1/x weighting factor was used to generate a calibration curve with the coefficients of determination ($r^2=0.9983$). The lower limit of quantification was $25ng/ml$ for the analyte. The process efficiency was 98.6~100.1%. Intra- and inter-day precisions were not more than 2.1% and 1.7%, while intra- and inter-day accuracies were ranged from -6.8 to 4.5%, respectively. The suitability of the method was examined by analyzing unknown forensic aqueous samples.

해외 고등학교 - 네덜란드 고등교육의 현안과 이슈, 볼로냐 프로세스 10년

최윤정,Choi, Yun-Jeong 한국대학교육협의회 2009 大學敎育 Vol.161 No.-

학습방법개선과 후처리 분석을 이용한 자동문서분류의 성능향상 방법

최윤정,박승수,Choi, Yun-Jeong,Park, Seung-Soo 한국정보처리학회 2005 정보처리학회논문지B Vol.12 No.7

자동문서분류는 문서의 내용에 기반하여 미리 정의된 항목에 자동으로 할당하는 작업으로서 효율적인 정보관리 및 검색등에 필수적인 작업이다. 기존의 문서분류성능 향상을 위한 연구들은 대부분 분류모델 자체를 개선시키는 데 주력해왔으며 통계적인 방법으로 그 범위가 제한되어왔다. 본 연구에서는 자동문서분류의 성능향상을 위해 데이터마이닝 기법과 결함허용방법을 이용하는 개선된 학습알고리즘과 후처 리 방법에 의한 RTPost 시스템을 제안한다. RTPost 시스템은 학습문서 선택작업 이전에 분류항목 설정의 문제를 다루며, 분류함수의 성능보다는 지정방식의 문제점을 감안하여 학습과 분류 후처리 프로세스를 개선하려는 것이다. 이를 통해 분류결과에 중요한 영향을 미쳐왔던 학습문서의 수와 선택방법, 분류모델의 성능등에 의존하지 않는 안정적인 분류가 가능하였고, 이를 분류오류율이 높은 경계선 인접영역에 위치한 문서들에 적용한 결과 높은 정확율을 얻을 수 있었다. 뿐만 아니라, RTPost 프로세스를 진행하는 동안 능동학습방법의 장점을 수용하여 학습효과는 높이며 비용을 감소시킬 수 있는 자가학습방법(self learning)방법의 효과를 기대할 수 있다. Automated text categorization is to classify free text documents into predefined categories automatically and whose main goals is to reduce considerable manual process required to the task. The researches to improving the text categorization performance(efficiency) in recent years, focused on enhancing existing classification models and algorithms itself, but, whose range had been limited by feature based statistical methodology. In this paper, we propose RTPost system of different style from i.ny traditional method, which takes fault tolerant system approach and data mining strategy. The 2 important parts of RTPost system are reinforcement training and post-processing part. First, the main point of training method deals with the problem of defining category to be classified before selecting training sample documents. And post-processing method deals with the problem of assigning category, not performance of classification algorithms. In experiments, we applied our system to documents getting low classification accuracy which were laid on a decision boundary nearby. Through the experiments, we shows that our system has high accuracy and stability in actual conditions. It wholly did not depend on some variables which are important influence to classification power such as number of training documents, selection problem and performance of classification algorithms. In addition, we can expect self learning effect which decrease the training cost and increase the training power with employing active learning advantage.

Identification of genomic regions associated with piglet survival and mortality

최윤정,김상욱,윤준호,Bong-Hwan Choi,Tae-Hun Kim,김관석 충북대학교 동물의학연구소 2014 Journal of Biomedical and Translational Research Vol.15 No.2

One of the major problems in the modern pig in- dustry is infectious disease. Susceptibility to infec- tious diseases is influenced by both constitutional (e.g. genotype, age, gender, and reproductive status) and environmental factors (e.g. nutrition, management, infections, and other forms of stress). Genetic varia- tions within individual animals or herds can cause dif- ferences in the execution of immune functions against infectious agents in domestic pigs. The objectives of the present study were to identify genetic factor(s) responsible for piglet survival and mortality under commercial field conditions with infectious diseases as well as determine QTL regions for immune capac- ity in a pig reference family. Sex ratio was examined between normal grown and presumed dead groups of F 2 animals generated by Korean native pigs (KNP) and Yorkshire (YS) breeds. The ratio of males was significantly higher in the presumed dead group than in the normal grown group. In order to study genetic factors associated with presumed mortality under dis- ease outbreak, allelic frequencies of 239 single nucleo- tide polymorphisms (SNPs) were compared between normal grown and presumed dead groups. Exactly 22 SNPs showed significant differences in their allelic frequencies between the two groups, and four of them were validated with another commercial population divided by normal and emaciated pigs. Furthermore, the relationships between 239 SNPs and immune- related traits were studied. These results demonstrate that identification of genetic components of animal im- mune systems and susceptibility to infectious diseases is possible and will be useful to improve disease resis- tance in individuals as well as in breeding programs.

사군자탕(四君子湯) 및 사물탕(四物湯)이 methotrexate로 유도(誘導)된 흰쥐의 면역기능저하(免疫機能低下)에 미치는 영향(影響)

최윤정,김장현,Choi Yun-Jung,Kim Jang-Hyun 대한한방소아과학회 1999 대한한방소아과학회지 Vol.13 No.1

The effects of Sagunjatang and Samultang on the immunosuppression induced by methotrexate(MTX) in rats were investigated in this study. The multiple parameters of immunity assessed in each rats included leukocyte count, lymphocyte rate, the number of lymphocyte in tibial bone marrow, contact hypersensitivity to DNFB, morphological change of thymocyte and IgG antibody on SDS-PAGE. Sprague-Dawley male rats were used and divided into five groups at random. Group A was normal control. Group B, the MTX treatment control, was injected i.v. with 2mg/kg of on days 9, 11 after sensitization with SRBC on 5th day. Group C, the experimental control, was treated Sagunjatang for 18days and MTX. Group D was treated Samultang for 18days and MTX. Group E was treated Sagunjatang-Samultang for 18days and MTX. The dosage of Sagunjatang and Samultang was $1m{\ell}/day$ respectively. In the case of Group E, rats Were fed Sagunjatang $1m{\ell}$ in the morning and Samultang $1m{\ell}$ in the afternoon. The results are summarized as follows: 1. Leukocyte count in rats induced by intravenous sensitization with SRBC was decreased significantly in Group E. 2. Leukocyte counts of 2weeks later after being treated MTX were increased significantly in Groups C and D. 3. Lymphocyte rate in rats induced by intravenous sensitization with SRBC wasn't changed significantly in all the experimental groups. 4. Lymphocyte rate of 2weeks. later after being treated MTX was increased significantly in Group D. 5. The number of lymphocyte in tibial bone marrow was incereased significantly in Group C. 6. Contact hypersensitivity wasn't changed significantly in all the experimental groups. 7. Morphological finding of thymocyte in group C was similar to normal group as compared with control group. 8. Purified IgG of all the experimental groups showed two bands of 50,000 and 25,000 on SDS-PAGE. But there was no difference among experimental groups.

의사결정나무 분석을 사용한 고가의료장비의 다빈도 사용 특성 분석

최윤정,곽민정,윤민,Choi, Yoon Jung,Kwak, Minjung,Yoon, Min 한국데이터정보과학회 2015 한국데이터정보과학회지 Vol.26 No.1

최근 고가의료장비의 도입으로 진단기술이 빠르게 발전하고 있으나 이에 따른 건강보험 재정의 부담이 크게 늘어 이에 대한 적절한 관리와 효율적 운영에 대한 정책이 필요하다. 이에 따라 본 연구에서는 의사결정나무분석 모형을 사용하여 CT 의료장비의 검사빈도에 영향을 미치는 요인을 파악하여 효율적 운영에 대한 방안을 제시한다. The cost of advanced medical technologies is commonly considered to be a major factor in the overall escalation of expenditures on health. The use of computed tomography (CT) scanning has increased dramatically over the past decade. CT has been rapidly adopted, despite their high cost. The aim of this study is to analysis the increasing factor of the frequency of the CT, using the decision tree model. Finally, we propose the effective policy option of diagnostic imaging technology in Korea.

Comparison of the mechanical properties and microstructures of fractured surface for Co-Cr alloy fabricated by conventional cast, 3-D printing laser-sintered and CAD/CAM milled techniques

최윤정,곽재영,허성주,김성균,안진수,박동수,Choi, Yun-Jung,Koak, Jai-Young,Heo, Seong-Joo,Kim, Seong-Kyun,Ahn, Jin-Soo,Park, Dong-Soo The Korean Academy of Prosthodonitics 2014 대한치과보철학회지 Vol.52 No.2

연구 목적: 본 연구의 목적은 주조, 3-D printing laser sintered 및CAD/CAM technology를 이용한 milling 방법으로 제작된 치과용 코발트-크롬 합금의 기계적 물성을 비교하고 파절 단면의 미세 구조를 살펴보는 데 있다. 이를 통해 새롭게 소개된 제작 기법 - 3D-printing laser sintered - 이 치과용 합금 제작으로 적합한 지 알아보고자 한다. 연구 재료 및 방법: 36개의 flat disc 모양의 시편을 제작하여 제작 방법에 따라 세 집단으로 나누었다; 주조 방식으로 제작한 12개, laser sintering 방법으로 12개, CAD/CAM milling 방법으로 12개의 시편을 제작하여 표면 경도 시험을 시행하였다. 또한 각 집단 별로 12개의 dumbbell 모양의 시편을 제작하여 인장 강도 시험을 시행하였다. 통계량이 비모 수적 통계 분포를 보였으므로 Kruskal-Wallis 검정을 이용하여 각 실험군의 인장 강도 시험 결과를 비교했으며, 통계적 유의 수준은P=.05로 설정하여 Mann-Whitney 및 Bonferroni 사후 검정을 시행하였다. 전자 주사 현미경을 사용하여 파절 단면의 미세 구조를 관찰하였다. 결과: Vickers hardness test에서 세 집단간에 모두 유의한 차이가 있었고, 주조 방식으로 제작된 실험군에서 가장 큰 표면 경도(455.88 Hv)가, CAD/CAM milling으로 제작된 실험군에서 가장 낮은 표면 경도(243.40 Hv)를 나타냈다. 최대 인장 강도, 0.2% 항복강도, elongation 및 elastic modulus에서 세 집단간에 모두 유의한 차이가 나타났으며, CAD/CAM milling으로 제작한 실험군에서 가장 높은 최대 인장 강도(1442.94 MPa)가, laser sintered 실험군에서 가장 큰 0.2% 항복 강도(1136.15 MPa)가 나타났다. 파절 단면의 전자 주사 현미경 관찰 결과, 주조 시편에서는 독특한 성긴 모양과 전형적인 주조 다공성 구조가 관찰되었고, laser sintered 시편에서는 편평한 면을 동반한 거친 결정 구조가, 그리고 milled 시편에서는 균일하고 규칙적인 치밀 미세 구조가 나타났다. 결론: 서로 다른 제작 방법은 코발트-크롬 합금의 물리적 성질과 파절 단면의 미세 구조에 영향을 미쳤다. 주조 방식으로 제작된 시편에서 가장 큰 표면 경도가, milling으로 제작된 시편에서 가장 큰 인장 강도를 나타냈으며, 본 연구의 모든 실험군에서 치과용 합금의 ISO 기준에 부합하는 물성을 보였다. Purpose: The purpose of present study is to compare mechanical properties and microstructural characteristics of fractured surface for cast, 3-D printing laser sintered and CAD/CAM milled cobalt-chromium (Co-Cr) alloy specimens and to investigate whether laser sintered technique is adequate for dental applications. Materials and methods: Thirty six flat disc shape Co-Cr alloy specimens were fabricated for surface hardness test and divided into three groups according to the manufacturing methods; 12 specimens for casting (n=12), 12 specimens for laser sintered technology (n=12) and 12 specimens for milled technology (n=12). Twelve dumbbell shape specimens for each group were also fabricated for a tensile test. Statistical comparisons of the mechanical properties for the alloys were performed by Kruskal-Wallis test followed by Mann-Whitney and Bonferroni test. The microstructural characteristics of fractured surfaces were examined using SEM. Results: There were significant differences in the mean Vickers hardness values between all groups and the cast specimen showed the highest (455.88 Hv) while the CAD/CAM milled specimen showed the lowest (243.40 Hv). Significant differences were found among the three groups for ultimate tensile strength, 0.2% yield stress, elongation, and elastic modulus. The highest ultimate tensile strength value (1442.94 MPa) was shown in the milled group and the highest 0.2% yield strength (1136.15 MPa) was shown in the laser sintered group. Conclusion: Different manufacturing methods influence the mechanical properties and microstructure of the fractured surfaces in Co-Cr alloys. The cast Co-Cr alloy specimens showed the highest Vickers hardness, and the CAD/CAM milled specimens revealed the highest tensile strength value. All alloys represent adequate mechanical properties satisfying the ISO standards of dental alloy.

논문편 : 소형아파트의 방위에 따른 실내온열환경 실태와 평가

최윤정,윤정숙 ( Yoon Jung Choi,Chung Sook Yoon ) 대한가정학회 1993 Human Ecology Research(HER) Vol.31 No.3

백내장이 동반된 녹내장 환자에서 수정체유화섬유주절제술과 섬유절제술의 치료효과 비교

최윤정,DouglasJ,Rhee,최규룡,Yun Jeong Choi,Douglas J,Rhee,Kyu-Ryong Choi 대한안과학회 2011 대한안과학회지 Vol.52 No.11

Purpose: To compare the treatment outcome and complications of phacotrabeculectomy and trabeculectomy in patients with glaucoma and cataracts. Methods: The authors of the present study retrospectively reviewed the records of 56 eyes that underwent phacotrabeculectomy and trabeculectomy with mitomycin-C between March 2006 and December 2009 in patients with glaucoma and cataracts. The change of intraocular pressure (IOP) and number of glaucoma medications up to 24 months postoperatively were compared and the treatment failure rate as well as postoperative complications analyzed. Results: IOP and number of glaucoma medications at 24 months after surgery were similar in the 2 groups. Additionally, both groups showed a significant decrease in IOP and number of glaucoma medications after surgery. The cumulative failure rates, frequency and distribution of postoperative complications were also similar in both groups and conjunctival bleb leak was the most common complication. Conclusions: Both phacotrabeculectomy and trabeculectomy showed long-term IOP reduction and a similar failure rate and complications. Therefore, both can be considered as a primary surgical treatment in patients with glaucoma and cataracts. In patients who need strict IOP control, trabeculectomy can be preferentially considered. If patients have visually significant cataracts or greater visual needs, phacotrabeculectomy can be considered. J Korean Ophthalmol Soc 2011;52(11):1308-1317

요로상피병변의 요세포학적 소견

최윤정,이광길,Choi, Yoon-Jung,Lee, Kwang-Gil 대한세포병리학회 1994 대한세포병리학회지 Vol.5 No.2

Urinary cytology is increasingly accepted as a diagnostic tool in the detection and follow-up of patients with bladder cancer. However, its value is reduced by several limitations, especially by the lack of cytologic criteria specifically reflecting the morphology of low-grade urothelial neoplasm. We reviewed histologically proven 50 cases of urine cytology with emphasis on cytologic findings of benign atypia and differential findings of urothelial neoplasm according to the grade. The diagnoses included 17 benign lesions(including 5 cases of urine calculi) and 33 malignant lesions (including 28 transitional cell carcinomas, 3 squamous cell carcinomas, 1 adenocarcinoma and 1 prostate adenocarcinoma), Diagnostic accuracy was 92%. Important cytodiagnostic criteria for benign atypia and low grade malignancy were cellularity, number of cell clusters, and morphology and arrangement of urothelial cells. The cytologic findings of urothelial neoplasms according to histologic grade were relatively well correlated with the histologic findings. However, the cytologic criteria were not sufficient to readily distinguish grade I from grade II. In view of this, we think that cytologic nomenclature "low-grade" and "high-grade" is a more reliable criterion. Recognition of subtle cellular morphologic features specific for urothelial lesions(including benign or malignancy) and proper fixation, processing and staining of specimen can expand the role of urinary cytology In detection and follow-up of patients.