• Molecules and Cells
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• 제46권4호
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• pp.209-218
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• 2023

In induced pluripotent stem cells (iPSCs), pluripotency is induced artificially by introducing the transcription factors Oct4, Sox2, Klf4, and c-Myc. When a transgene is introduced using a viral vector, the transgene may be integrated into the host genome and cause a mutation and cancer. No integration occurs when an episomal vector is used, but this method has a limitation in that remnants of the virus or vector remain in the cell, which limits the use of such iPSCs in therapeutic applications. Chemical reprogramming, which relies on treatment with small-molecule compounds to induce pluripotency, can overcome this problem. In this method, reprogramming is induced according to the gene expression pattern of extra-embryonic endoderm (XEN) cells, which are used as an intermediate stage in pluripotency induction. Therefore, iPSCs can be induced only from established XEN cells. We induced XEN cells using small molecules that modulate a signaling pathway and affect epigenetic modifications, and devised a culture method which can produce homogeneous XEN cells. At least 4 passages were required to establish morphologically homogeneous chemically induced XEN (CiXEN) cells, whose properties were similar to those of XEN cells, as revealed through cellular and molecular characterization. Chemically iPSCs derived from CiXEN cells showed characteristics similar to those of mouse embryonic stem cells. Our results show that the homogeneity of CiXEN cells is critical for the efficient induction of pluripotency by chemicals.

• Journal of Gastric Cancer
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• 제6권4호
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• pp.237-243
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• 2006

목적: 간전이 위암환자들을 대상으로 치료 결과를 알아보고 생존 분석을 통해 예후를 확인하고자 하였다. 대상 및 방법: 1990년 3월부터 2006년 3월까지 영남대학교 영남의료원 내과 및 외과에 내원한 위암환자 중 간전이가 발견된 85예(동시성 62예, 이시성 23예)를 대상으로 후향적 연구를 시행하였다. 임상병리학적 인자와 위절제술, 간전이병소 절제술 및 항암화학요법 등 치료 관련 인자들에 대해 생존분석을 실시하였다. 결과: 간전이 위암환자들의 중앙생존기간은 11개월(동시성 11개월, 이시성 17개월)이었다. 동시성 간전이군의 경우 위절제율은 24.1%, 간전이병소 절제율은 16.1%였다. 간외 전이 동반율은 23.5%였고 생존기간에 차이가 있었다(P<0.05). 간전이 병소 절제 및 위절제군, 위절제군, 비절제군의 중앙생존기간은 각각 60개월 이상, 10개월 및 9개월이었다(Fig. 1, P<0.05). 이시성 간전이군의 경우 위암절제 후 무병생존기간의 중앙치는 8개월이었으며 초기병기와 간전이 빈도 사이에는 차이가 없었다. 동시성 간전이군에서는 단변량 분석 결과 간외 전이, 위절제술, 간전이 병소 절제술, 외과적 절제 형태 및 항암화학요법에 대한 반응이 유의하였고 다변량 분석 결과 간전이병소 절제술, 항암화학요법에 대한 반응 및 간외 전이가 독립적 예후인자였고, 이시성 간전이군에서는 간외 전이, 항암화학요법에 대한 반응 및 원발암 세포의 분화도가 유의하였고 간외 전이가 독립적 예후인자였다. 결론: 간전이 위암환자에서 예후는 간전이 병소의 절제, 원발 병소의 절제, 간외 전이 유무 및 항암화학요법에 대한 반응여부에 의해 결정되므로 치료에 있어 간외 전이가 없는 경우 보다 적극적인 절제 노력과 항암화학요법이 생존율 향상에 기여할 것으로 판단된다.

• 경영과정보연구
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• 제1권
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• pp.193-228
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• 1997

Behaviors of organizational members can be classified as two types. One is behavior required to perform formally given job. The other is a various kind of behavior taken voluntarily but not required directly and formally to perform job. The former can be called as in-job behavior while the latter can be called as extra-job behavior. Many organizational scientists so far, have focused on investigating in-job behavior. Yet, from a decade, organizational researchers have recognized that in-job behavior alone can not explain sufficiently job performance or organizational effectiveness Thus. they have paid attention to extra-job behavior, which is generally called as organizational citizenship behavior. Existing studies of organizational citizenship behavior have three types : First type is studying the concept and components of organizational citizenship behavior. Second tope is studying the determinants of organizational citizen-ship behavior and relationships with it. And third type is studying relatioships between organizational citizenship behavior and job performance. This study, therefore, have purposes as follows : Firstly, this study designs a comprehensive model in the below figure and generates inclusive hypotheses about relationships among antecedents, intermediate factors, and the components of organizational citizenship behavior. Secondly, this study investigating empirically such relationships and draws a picture of mediation roles of the intermediate variables. To design the model and generate the hypotheses, this study conducted a comprehensive literature survey on organizational citizenship behavior. To test the hypotheses, this study collected data from 847 employees at 12 large genral hospitals in Pusan area through a questionnaire survey and conducted the three step mediated regression analysis using the SAS-PC Package.

• 한국항공운항학회지
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• 제19권1호
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• pp.58-65
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• 2011

The purpose of this study is to describe upon the most effective leadership stlyes for Airlines based on the transformational and transactional leadership that Bernard M.Bass proposed. The outcome of leadership treated here will be employee's extra efforts, employee's satisfaction with the leader, the effectiveness of the leader, involvement by employees in the organization, and management outcomes perceived by employees. The result of correlation showed that transformational leadership factors had positive impacts on the outcomes of leadership, but the transactional leadership had a negative impact on outcomes of leadership. According to results of multiple regression analyses, transformational leadership had a grater positive impact on outcomes of leadership than did transactional leadership. Transformational leadership is expected to promote and enhance the effectiveness of the hotel leaders, as well as the airline employee's extra effort, their satisfaction with the leader, involvement in the organization, and their perception of management outcomes. It is imperative that the airline industry continues to develop transformational leader.

• 한국자기공명학회논문지
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• 제9권1호
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• pp.29-37
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• 2005

Intra-cellular drug uptake in Xenopus laevis oocyte has been elucidated using localized MR spectroscopy (MRS) and PFG NMR techniques at a 600 $MH_z$(Bruker, 14.1 T) NMR spectrometer. The localized MRS has been done with a homemade probe, and shows the intra-cellular uptake of nicotinamide. The self-diffusion of the molecule in Xenopus oocyte was obtained by PFG NMR technique. The measured data are well fitted with a linear combination of two exponential functions, which shows that there are two types of drug molecules, intra-and extra-cellular molecules. Diffusion coefficients of intra- and extra-cellular drug molecules are 3.7 $\times$ $10^{-11}$ $\m^{2}/s$and 6.4 $\times$ $10^{-10}$ $\m^{2}/s$, respectively. In the weighting factors there is shown that about 5% of drug molecule is inside the cells. These techniques can be used for drug screening in molecule-, cell-, and tissue-based preclinical test.

• Korean Journal of Acupuncture
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• 제34권4호
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• pp.231-240
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• 2017

Objectives : This study was designed to establish the basis for expanding the indications for Blood-letting therapy by reviewing the contents recorded in the Zhenjiudacheng. Methods : Articles associated with the Blood-letting therapy were categorized according to the factors such as the characteristics of the treatment site, the used instruments, the caution, the side effects, the diseases, the acupoints, etc. Results : 1. The characteristics of treatment site were the red, purple, purplish red, purplish black color and the localized collection of fibrous exudate. 2. There were several instruments used for Blood-letting therapy; Samreongchim, Sochim, Loguan, Stone needle, Jukyeop, etc. 3. Several cautions and side effects of the Blood-letting therapy were recorded in the Zhenjiudacheng. 4. The Blood-letting therapy could be performed for a broad spectrum of symptoms such as headaches, backaches, schizophrenia, hyperemia, etc. 5. Not only acupoints but also extra points were used for blood-Letting therapy. 6. In addition to the usual Blood-letting region, Blood-letting therapy was performed directly on the pathologic site and pathologic reaction site. Conclusions : In the Zhenjiudacheng, Blood-letting therapy was described in a concrete and substantive manner in order to enable practical clinical application.

• 생태와환경
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• 제50권1호
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• pp.16-28
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• 2017

In an aquatic environment, toxicity of metals to organisms depends on external factors (type of metal, exposure concentration and duration, environmental parameters, and water quality) and intracellular processes(metal-binding sites and detoxification). Toxicity of copper(Cu) on the marine microalga Tetraselmis suecica was investigated in this study. Dose-dependent (Cu concentration dependent) inhibition of growth and cell division, as well as, variation of intra- and extra-cellular Cu, Fe and Zn content was observed. T. suecica was sensitive to Cu; the 96 h $EC_{50}$ (concentration to inhibit growth-rate by 50%) of growth rate (${\mu}$) ($21.73{\mu}M\;L^{-1}$), cell division $day^{-1}$ ($18.39{\mu}M\;L^{-1}$), and cells $mL^{-1}$ ($13.25{\mu}M\;L^{-1}$) demonstrate the toxicity of Cu on this microalga. High intra-($19.86Pg\;cell^{-1}$) and extra-cellular($54.73Pg\;cell^{-1}$) Cu concentrations were recorded, on exposure to 24.3 and $72.9{\mu}M\;L^{-1}$ of Cu.

• 한국해양공학회지
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• 제26권5호
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• pp.87-93
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• 2012

Many longitudinally-arranged pipes in ships are equipped with loops as a measure to reduce stresses caused by displacement loads conveyed from the hull girder bending and/or thermal loads of carried fluid of non-ambient temperature. But as the loops have some negative effects such as causing extra manufacturing cost and occupying extra space, the number and the dimensions of the loops need to be minimized. In the meanwhile, a design formula for pipe loops has been developed by modeling them as a spring element of which stresses and axial stiffness are calculated based on the beam theory. But as the beam theory turns out to be inappropriate to deal with the complex structural behavior in the curved corner portion of the loop, this paper aims at improving the previously developed design formula by adopting correction factors which can allow for the gap between the results of beam theory and a more accurate analysis. This paper adopts a finite element analysis with two-dimensional shell elements with some validation work for it. The paper ends with a sample application of the proposed formulas showing their accuracy and efficiency.

• Journal of Interdisciplinary Genomics
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• 제4권2호
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• pp.24-30
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• 2022

Klinefelter's syndrome (KS) is a syndrome with extra X chromosome(s), in XY individuals, characterized by gynecomastia, small testes, and infertility. Additional X chromosomes can be present as variable karyotypic forms, including mosaicism (47,XXY/46,XY). The reported prevalence of KS ranges from one in 500 to one in 1,000 live males, but is probably underestimated. The classic phenotype is small, firm testes and infertility resulting from seminiferous tubule dysgenesis and androgen deficiency. The spectrum of KS includes tall stature with relatively long legs and arm span, decreased body hair, learning disabilities, behavioral problems, poor motor skills, and other important medical issues, such as metabolic syndrome, diabetes, autoimmune diseases, cardiovascular disease, certain neoplasia. The increased risk of certain medical problems in KS can be attributed to a direct effect of the extra X chromosome, the combined action of multiple genomic and epigenetic factors, or the hormonal imbalances. Typically, chromosome analysis is not ordered for adult patients with general medical conditions, except for suspected cases of hematologic and lymphoid disorders. Even though it was found during work-up for certain disorders in adult patient, most physicians do not suspect KS or consider its impact. Therefore, understanding the pathophysiology and variable manifestation in KS is necessary, and discussions with multidisciplinary teams will help to diagnose and treat males with KS.

• 한류연구
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• 제2권2호
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• pp.1-8
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• 2023

The present study examines the connections and effects of these historical events on South Korea's education system. The research seeks to illuminate private education's complex history and the complex factors that have shaped it by examining these historical trajectories. After the Korean War in the mid-20th century, South Korea went from agrarian to industrial, which shaped private education. Unparalleled economic growth in the 1960s and 1980s altered schooling. South Korea quickly became an industrial powerhouse, and education became crucial for families seeking socioeconomic advancement. The growing middle class, believing education was the key to prosperity, demanded more extra education. South Korean private education's fourth major event occurred during the socioeconomic upheavals of the 1960s-1980s. Prior studies explain how the fast transition from agrarian to industrial society made schooling essential for families seeking upward mobility. Due to the demand for extra education, private tutoring and specialist hagwons flourished. In summary, this study insists that the effects of historical events on South Korean private education demonstrate the interconnection of cultural, economic, and sociological aspects. Educational practitioners must comprehend the historical backdrop, recognize the lasting impact of past events, and use literature-based tools to navigate this complex landscape.