• Molecules and Cells
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• 제42권3호
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• pp.200-209
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• 2019

Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have been used as promising tools for regenerative medicine, disease modeling, and drug screening. Traditional and common strategies for pluripotent stem cell (PSC) differentiation toward disease-relevant cell types depend on sequential treatment of signaling molecules identified based on knowledge of developmental biology. However, these strategies suffer from low purity, inefficiency, and time-consuming culture conditions. A growing body of recent research has shown efficient cell fate reprogramming by forced expression of single or multiple transcription factors. Here, we review transcription factor-directed differentiation methods of PSCs toward neural, muscle, liver, and pancreatic endocrine cells. Potential applications and limitations are also discussed in order to establish future directions of this technique for therapeutic purposes.

• Clinical and Experimental Reproductive Medicine
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• 제45권4호
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• pp.149-153
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• 2018

Stem cells are undifferentiated cells capable of self-renewal and differentiation into various cell lineages. Stem cells are responsible for the development of organs and regeneration of damaged tissues. The highly regenerative nature of the human endometrium during reproductive age suggests that stem cells play a critical role in endometrial physiology. Bone marrow-derived cells migrate to the uterus and participate in the healing and restoration of functionally or structurally damaged endometrium. This review summarizes recent research into the potential therapeutic effects of bone marrow-derived stem cells in conditions involving endometrial impairment.

• BMB Reports
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• 제56권1호
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• pp.2-9
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• 2023

Hair follicles in the skin undergo cyclic rounds of regeneration, degeneration, and rest throughout life. Stem cells residing in hair follicles play a pivotal role in maintaining tissue homeostasis and hair growth cycles. Research on hair follicle aging and age-related hair loss has demonstrated that a decline in hair follicle stem cell (HFSC) activity with aging can decrease the regeneration capacity of hair follicles. This review summarizes our understanding of how age-associated HFSC intrinsic and extrinsic mechanisms can induce HFSC aging and hair loss. In addition, we discuss approaches developed to attenuate ageassociated changes in HFSCs and their niches, thereby promoting hair regrowth.

• East Asian mathematical journal
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• 제39권4호
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• pp.377-392
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• 2023

The purpose of this research was to investigate mathematics teachers' beliefs regarding the implementation of STEM approaches in secondary school mathematics classes and to identify the factors influencing their beliefs. A survey on teachers' beliefs about applying STEM in mathematics classes was developed and distributed online to mathematics teachers from middle and high schools in two metropolitan areas. Eighty-two surveys were returned from the teachers. Factor analysis revealed that the items were distributed among five main aspects. The findings indicated that most teachers believed in the necessity of implementing STEM education. However, some teachers expressed concerns about the effectiveness of implementation due to the lack of materials, resources, and equipment needed for STEM implementation.

• International Journal of Stem Cells
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• 제16권3호
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• pp.260-268
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• 2023

Intrauterine adhesion (IUA) can occur after trauma to the basal layer of the endometrium, contributing to severe complications in females, such as infertility and amenorrhea. To date, the proposed therapeutic strategies are targeted to relieve IUA, such as hysteroscopic adhesiolysis, Foley catheter balloon, and hyaluronic acid injection have been applied in the clinic. However, these approaches showed limited effects in alleviating endometrial fibrosis and thin endometrium. Mesenchymal stem cells (MSCs) can offer the potential for endometrium regeneration owing to reduce inflammation and release growth factors. On this basis, MSCs have been proposed as promising methods to treat intrauterine adhesion. However, due to the drawbacks of cell therapy, the possible therapeutic use of extracellular vesicles released by stem cells is raising increasing interest. The paracrine effect, mediated by MSCs derived extracellular vehicles (MSC-EVs), has recently been suggested as a mechanism for their therapeutic properties. Here, we summarizes the main pathological mechanisms involved in intrauterine adhesion, the biogenesis and characteristics of extracellular vesicles, explaining how these vesicles could provide new opportunities for MSCs.

• International Journal of Stem Cells
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• 제15권1호
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• pp.26-40
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• 2022

Region specific brain organoids are brain organoids derived by patterning protocols using extrinsic signals as opposed to cerebral organoids obtained by self-patterning. The main focus of this review is to discuss various region-specific brain organoids developed so far and their application in modeling neurodevelopmental disease. We first discuss the principles of neural axis formation by series of growth factors, such as SHH, WNT, BMP signalings, that are critical to generate various region-specific brain organoids. Then we discuss various neurodevelopmental disorders modeled so far with these region-specific brain organoids, and findings made on mechanism and treatment options for neurodevelopmental disorders (NDD).

• 한국산림과학회지
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• 제98권6호
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• pp.633-638
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• 2009

본 연구는 인도네시아 칼리만탄 지역의 유칼립투스 및 아카시아 조림지에 대해 수간곡선식을 도출하고 수간재적표를 조제하고자 하였다. 유칼립투스와 아카시아 조림지에 적합한 수간곡선식의 도출을 위해서 Max&Burkhart식 등 세 가지 수간곡선 모형을 적용하였으며, 적합도, 편의, 잔차의 표준 편차 등의 통계량을 분석하여 각 모델의 적합성을 평가하였다. 그 결과 유칼립투스와 아카시아의 수간생장을 표현하는 데에는 Kozak식이 가장 적합한 것으로 나타났다. 따라서 Kozak식을 이용하여 유칼립투스와 아카시아의 수간재적표를 조제하였으며, 현지에서 이용되는 지방적 재적표 상의 동일 크기 임목과 비교한 결과 큰 차이가 없는 것으로 나타났다. 본 연구에서 제시된 해외조림지 임목생장에 대한 정보를 토대로 해외조림지에 대한 보다 효율적인 의사결정이 가능하고 체계적인 산림경영이 이루어질 것으로 기대한다

• 정보교육학회논문지
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• 제15권1호
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• pp.11-22
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• 2011

이 연구는 교육용 로봇을 활용한 STEM 통합교육이 학업성취, 교과 태도에 미치는 효과를 알아보기 위해 수행되었다. 연구대상은 초등학교 6학년 2개반 73명을 선정하였으며, 실험집단은 교육용 로봇을 활용한 STEM 통합교육을, 통제집단은 교과서 중심의 분과형 수업을 12차시 동안 처치하였다. 연구의 결과로 첫째, 인지적 영역인 수학 과학 학업성취에 있어서 교육용 로봇을 활용한 STEM 통합교육은 교과서 중심의 분과형 수업보다 더 효과적이었다. 특히, 학업성취 하위요인인 지식, 이해, 적용 영역으로 사후 검증한 결과 지식영역에서는 두 집단 간 통계적으로 유의한 차이가 없었으나, 이해와 적용 영역에서는 실험집단이 통계적으로 유의하게 향상됨을 확인할 수 있었다. 둘째, 정의적 영역인 교과 태도 수준에 있어서 실험집단이 통제집단에 비해 긍정적인 영향이 있음을 확인할 수 있었다. 교육용 로봇을 활용한 STEM 통합교육은 현행 수학 과학 교과의 정의적 영역인 흥미를 보완할 수 있는 하나의 방법이 될 수 있으리라 기대한다.

• 대한지구과학교육학회지
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• 제10권1호
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• pp.1-16
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• 2017

본 연구는 북미 토착민인 인디언 학생들을 대상으로 설계된 문화 반영적 융합교육(STEM)을 이용한 문제해결 수업을 보여준다. 이 수업은 악기상을 고려한 Shelter Design 또는 피난처 설계에 관한 것이었다. 이 수업은 인디언 학생들을 대상으로 6일간 여름방학캠프 프로그램으로 적용되었으며 모든 수업은 인디언 보호구역에 있는 학교에서 실시되었다. 본 연구를 위한 데이터로는 학생들의 Shelter Design 그림, 그림에 대한 부연 설명, 그리고 학생용 학습지였다. 데이터는 질적 분석 방법에 의해 분석되었다. 본 연구의 결과 학생들은 문화 반영적(STEM) 수업 후 STEM 지식을 더 많이 습득하였으며, Shelter Design활동을 하는 동안 학생들의 문화적 지식과 일상생활 경험 등을 활용하여 문제를 해결하는 것으로 드러났다.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.78-78
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• 2003

Adult stem cells can make identical copies of themselves for long periods of time. They also give rise to many differentiated mature cell types that have characteristic morphology and specialized function. Human adult stem cells are the attractive raw materials for the cell/tissue therapy, however, it is not easy to get from the adult tissues. In the present study, we tried to isolate a cell population derived from human umbilical cord vein which has been discarded after birth. The cells were isolated after treatment of the umbilical vein with collagenase or trypsin. After 3 days of culture, two kinds of cell populations were found consisting of adherent cells with endothelial cell-like and fibroblast-like morphology, respectively. When these cells were subcultured 12 times over a period of 3 months, almost cells appeared uniformly to exhibit fibroblastoid morphology which was different from that of mesenchymal stem cells obtained from human bone marrow The results of RT-PCR analyses showed distinct expression of BMP-4, oct-4, and SCF genes but not of GATA, PAX-6 and Brachyury genes. On immunohistochemical staining, the cells were negative for the von Willebrand factor(vWF), alpha-smooth muscle actin and placental alkaline phosphatase. From these observations, it is suggested that stem-like cells might be present in human umbilical cord vein.