• International Journal of Oral Biology
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• 제36권1호
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• pp.31-35
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• 2011

Teeth develop via a reciprocal induction between the ectomesenchyme originating from the neural crest and the ectodermal epithelium. During complete formation of the tooth morphology and structure, many cells proliferate, differentiate, and can be replaced with other structures. Apoptosis is a type of genetically-controlled cell death and a biological process arising at the cellular level during development. To determine if apoptosis is an effective mechanism for eliminating cells during tooth development, this process was examined in the rat mandible including the developing molar teeth using the transferase-mediated dUTP-biotin nick labeling (TUNEL) method. The tooth germ of the mandibular first molar in the postnatal rat showed a variety of morphological appearances from the bell stage to the crown stage. Strong TUNEL-positive reactivity was observed in the ameloblasts and cells of the stellate reticulum. Odontoblasts near the prospective cusp area also showed a TUNEL positive reaction and several cells in the dental papilla, which are the forming pulp, were also stained intensively in this assay. Our results thus show that apoptosis may take place not only in epithelial-derived dental organs but also in the mesenchyme-derived dental papilla. Hence, apoptosis may be an essential biological process in tooth development.

• 한국학교보건학회지
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• 제17권1호
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• pp.55-69
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• 2004

Purpose ： To describe epidemiological characteristics and related factors in school personnel with hypertension. Method ： 5,384 school personnel (2,638 males and 2,746 females) received physical examination at the Seoul School Health Center in 2002. blood pressure(BP) was classified by JNC 7th report. Normal BP is systolic BP <120 and diastolic BP<80, prehypertension BP is 120-139 or 80-89mmHg, stage 1 hypertension BP is 140-159 or 90-99, and stage 2 hypertension >=160 or >=100 mmHg. each group was evaluated by gender. We used multiple regression and logistic regression. Results ： Normotension was 20.13% in males and 48.65% in female, prehypertension 43.4% in males and 38.06% in females, stage 1 hypertension 26.38% in males and 10.99% in females, stage2 hypertension 9.59% in males and 3.2% in females. the older age group had higher distribution of stage 1 hypertension and stage 2 hypertension. The means and abnormal rates of BMI, blood sugar, total cholesterol, GOT, GPT, and GTP was higher when their blood pressure was higher. However, an alcohol habit among lifestyle factors had an inverse effect. Higher Bp was correlated to a higher BMI, FBS, and cholesterol-like dose response. In stage 1 hypertension, the related factors of hypertension for males were BMI, amount of cigarettes smoked, exercise, blood sugar, total cholesterol, and GTP. In stage 1 hypertension, age, BMI, exercise, blood sugar, total cholesterol were related factors in female. In stage 2 hypertension, age and smoking were related factors in male, and age, BMI, and cholesterol in female. Conclusions ： It is possible to intervene in all related factors of hypertension except age through life-style modification and appropriate medical management. Active health promotion is needed in School personnel.

• 멤브레인
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• 제26권2호
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• pp.159-165
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• 2016

다단기체분리 공정을 수행하기 위해 폴리이미드 중공사막 모듈을 제조하여 혼합기체 $N_2$ : $SF_6$ = 50 : 50에 대한 기체분리특성을 확인하였다. 제조된 중공사막 모듈은 0.5 MPa에서 stage cut을 조절하여 투과 유량, 농도 등의 성능을 측정하였다. 중공사막 모듈은 1단 분리 테스트에서 $N_2/SF_6$ 선택도가 높을수록 동일한 stage cut에서 높은 $SF_6$ 회수율을 얻을 수 있었다. 1단 시험결과에 따라 $SF_6$ 회수율과 농축농도를 동시에 높이기 위해 2단 기체 분리 테스트 진행함으로써 $SF_6$ 회수율 95% 이상, $SF_6$ 회수농도 98% 이상을 농축할 수 있었다.

• Journal of Animal Science and Technology
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• 제52권6호
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• pp.467-473
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• 2010

A total of 4,323,781 records for informal 16 primary linear descriptive traits of dairy cows in Holstein breed from 1988 to 2007 in USA were analyzed to estimate adjustment factors for lactation number and stage. While all factors in the model were highly significant (P < 0.01), major influences on linear type traits were due to lactation number and stage. The frequencies of lactation number 1 through 6 were 58.6, 22.0, 11.8, 4.8, 2.1, and 0.8%, respectively. Further, the frequencies of lactation stage were 0.7, 76.9, 15.3, 4.9, and 2.1%, respectively, for springing, early, medium, late, and dry. To adjust 16 linear traits (stature, dairy form, strength, body depth, rump width, rump angle, legs rear view, leg set, foot angle, fore udder, rear udder height, rear udder width, udder support, udder depth, and front teat placement), additive and multiplicative adjustment factors of lactation number (lactations 2 to 4) and stage (springing, medium, late and dry) were estimated with the solutions in the generalized linear model, assigning lactation 1 and stage early as base class. Additive adjustment factors of lactation number ranged from -1.23 to 2.908, while multiplicative factors ranged from 0.853 to 2.207. Further, additive and multiplicative adjustment factors for lactation stage ranged from -0.668 to 0.785, and from 0.891 to 1.154. Application of adjustment factors to 20 randomly sampled sub-data sets produced the results that additive adjustment factors for both lactation number and stage reduced more mean square of lactation number and stage over 16 linear traits than any combination of adjustments, and leaded additive adjustment factors for both lactation number and stage as a choice of methods for adjustment of informal 16 primary linear type traits collected by classifiers of AI studs.

• 미생물학회지
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• 제16권3호
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• pp.122-130
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• 1978

Saccharomyces cerevisiae J170, matant를 사용하여 YEP 배지에서 20시간 진탕 배양하여 생장이 왕성한 영양시기의 효모세포를 얻었다. 이 세포를 sporulation medium에 접종하여 $30^{\circ}C$에서 20시간 진탕 배양하면 약 80%의 ascospore를 형성함을 볼 수 있었다. 포자행성시기와 생장시기를 택하여 D-$^{14}C$-glucose 운반에 관하여 바교 검도한 결과는 다음파 같다. haploid인 포자형성시나 diploid인 생장시기의 포도당 흡수는 pH6.0에서 최대이었다. 이 두 시기의 포도당 운반은 2, 4-dinitrophenol에 의하여 저해되었으므로 포자형성기의 포도당운반도 역시 egergy를 요구하는 능동수송파 연관이 있음을 알게 되었다. 생장시기의 포도당 흡수정도는 포자형성기 보다 높았으며 이때에 fructose나 galactose와 포도당흡수의 관계는 서로 경쟁적으로 작용함을 알 수 있었다. 효모세포의 당 성분은 ribose, mannose, $\alpha$, $\beta$-glucose로 되어 있으며 특히 포자형성기의 mannose 함량은 영양세포 때보다 현저히 적었다.

• Industrial Engineering and Management Systems
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• 제14권1호
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• pp.22-31
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• 2015

In this paper, a two-stage hybrid flow shop problem is considered. Specifically, there exist identical parallel machines at stage 1 and two dedicated machines at stage 2, and the objective of the problem is to minimize makespan. After being processed by any machine at stage 1, a job must be processed by a specific machine at stage 2 depending on the job type, and one type of jobs can have different processing times on each machine. First, we introduce the problem and establish complexity of several variations of the problem. For some special cases, we develop optimal polynomial time solution procedures. Then, we establish some simple lower bounds for the problem. In order to solve this NP-hard problem, three heuristics based on simple rules such as the Johnson's rule and the LPT (Longest Processing Time first) rule are developed. For each of the heuristics, we provide some theoretical analysis and find some worst case bound on relative error. Finally, we empirically evaluate the heuristics.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1207-1210
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• 2003

This paper deals with experiments for dynamic characteristics and performance evaluation of the 3-axis fine positioning stage developed in [1]. The features of the developed fine positioning stage are the long stroke due to the magnetically preloaded PZT actuators, the minimum motion crosstalk due to the use of a ball contact mechanism and the compact design. The dynamic characteristics of the actuator and the stage are tested with the preload changed in order to validate the actuator and the stage design. Performance evaluation is also made for the PZT actuators as well as the stage positioning accuracy. Experimental results show that the developed stage is accurate enough to be used for nanometer positioning.

• 한국경영과학회지
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• 제4권1호
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• pp.51-67
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• 1979

This paper considers the problem of determining an optimal dynamic operating policy for a two-stage tandem queueing service system in which the service facilities (or stages) can be operated at more than one service rate. At each period of the system's operation, the system manager must specify which of the available service rates is to be employed at each stage. The cost structure includes an operating cost for running each stage and a service facility profit earned when a service completion occurs at Stage 2. We assume that the system has a finite waiting capacity in front of each station and each customer requires two services which must be done in sequence, that is, customers must pass through Stage 1 and Stage 2 in that order. Processing must be in the order of arrival at each station. The objective is to minimize the total discounted expected cost in a two-stage tandem queueing service system, which we formulate as a Discrete-Time Markov Decision Process. We present analytical and numerical results that specify the form of the optimal dynamic operating policy for a two-stage tandem queueing service system.

• 한국결정학회:학술대회논문집
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• 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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• pp.36-36
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• 2002

To Establish of standard technique of length measurent in 2D plane, we develope AFM system. The XY scanner scans the sample only in XY plane, while the Z scanner scans the specimen only in Z-direction. Cantilever tip is controlled to has constant height relative to speciman surface by feedback of PSPD signal. To acquire high accuracy, Z-axis measuring sensor will be added.(COXI or others). In this paper we design XYZ stage suitable for this AEM system. For XY stage, single module parallel-kinnematic flexure stage is used which has high orthogonality and minimum out-of-plane motion. To obtain best performance optimal design is performed. For XY stage, to be robust about parasitic motion optimal design of maximizing Z and tilt stiffness is performed under the constraint of motion range and stage size. And for Z stage, optimal design of maximizing 1st resonant frequency is performed. Because if resonant frequency is get higher, scan speed is improved. So it makes reduce the error by sensor drift. Resultly XYZ stage each have 1st natural frequency of 115㎐, 201㎐, 2.66㎑ and range 109㎛, 110㎛, 12㎛.

• 한국정밀공학회지
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• 제21권3호
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• pp.155-162
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• 2004

This paper presents the fabrication procedure and the experiments for the 3-axis fine positioning stage proposed in［1］. First, the dynamic characteristics of the actuator and the stage are tested with the preload changed in order to validate the stage design specifications. Secondly, the performance of the stage is also evaluated on the accuracy associated with linear positioning, angular error, and straightness error. Experimental results show that the developed stage is accurate enough to be used for nanometer positioning. Through the analysis and experiment, the developed fine positioning stage are found to have a long stroke due to the magnetically preloaded PZT actuators, the minimum motion crosstalk due to the use of a ball contact mechanism and the compact design.