• Journal of Periodontal and Implant Science
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• 제41권4호
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• pp.192-200
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• 2011

Purpose: The aim of this study is to compare the gene expression profile in mesenchymal stem cells derived from dental tissues and bone marrow for characterization of dental stem cells. Methods: We employed GeneChip analysis to the expression levels of approximately 32,321 kinds of transcripts in 5 samples of bone-marrow-derived mesenchymal stem cells (BMSCs) (n=1), periodontal ligament stem cells (PDLSCs) (n=2), and dental pulp stem cells (DPSCs) (n=2). Each cell was sorted by a FACS Vantage Sorter using immunocytochemical staining of the early mesenchymal stem cell surface marker STRO-1 before the microarray analysis. Results: We identified 379 up-regulated and 133 down-regulated transcripts in BMSCs, 68 up-regulated and 64 down-regulated transcripts in PDLSCs, and 218 up-regulated and 231 down-regulated transcripts in DPSCs. In addition, anatomical structure development and anatomical structure morphogenesis gene ontology (GO) terms were over-represented in all three different mesenchymal stem cells and GO terms related to blood vessels, and neurons were over-represented only in DPSCs. Conclusions: This study demonstrated the genome-wide gene expression patterns of STRO-$1^+$ mesenchymal stem cells derived from dental tissues and bone marrow. The differences among the expression profiles of BMSCs, PDLSCs, and DPSCs were shown, and 999 candidate genes were found to be definitely up- or down-regulated. In addition, GOstat analyses of regulated gene products provided over-represented GO classes. These data provide a first step for discovering molecules key to the characteristics of dental stem cells.

• 한국가스학회지
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• 제11권4호
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• pp.1-6
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• 2007

본 논문은 LPG 엔진에서 밸브스템의 표면거칠기가 오일 누설에 미치는 영향에 대한 실험적 결과를 제공하고자 한다. 밸브스템시일은 밸브스템과의 미세한 밀봉간극을 통해 유출하는 오일을 차단하기 위한 부품이다. 이들 두개의 부품사이에서 발생되는 밀봉성은 밸브스템과 밸브스템시일의 누유안전성과 수명연장에 관련된 중요한 요소이다. 본 실험결과에 의하면, 밸브스템의 표면거칠기를 중심선 표면거칠기, Ra로 나타낼 경우 $0.4{\sim}0.5{\mu}m$가 최적의 가공조건이고, 표면의 거칠기 단면형상은 균일하게 분포되도록 가공하는 것이 가장 이상적인 설계조건이 될 것이다. 기본적으로 매끄러운 밸브표면과 균일하게 분포된 거칠기 형상을 유지하는 것이 밸브스템과 밸브스템 시일장치의 간극을 통해 빠져나가는 누유량을 줄일 수 있다.

• 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.

• BMB Reports
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• 제55권5호
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• pp.205-212
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• 2022

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating chronic disorder characterized by suprapubic pain and urinary symptoms such as urgency, nocturia, and frequency. The prevalence of IC/BPS is increasing as diagnostic criteria become more comprehensive. Conventional pharmacotherapy against IC/BPS has shown suboptimal effects, and consequently, patients with end-stage IC/BPS are subjected to surgery. The novel treatment strategies should have two main functions, anti-inflammatory action and the regeneration of glycosaminoglycan and urothelium layers. Stem cell therapy has been shown to have dual functions. Mesenchymal stem cells (MSCs) are a promising therapeutic option for IC/BPS, but they come with several shortcomings, such as immune activation and tumorigenicity. MSC-derived extracellular vesicles (MSC-EVs) hold numerous therapeutic cargos and are thus a viable cell-free therapeutic option. In this review, we provide a brief overview of IC/BPS pathophysiology and limitations of the MSC-based therapies. Then we provide a detailed explanation and discussion of therapeutic applications of EVs in IC/BPS as well as the possible mechanisms. We believe our review will give an insight into the strengths and drawbacks of EV-mediated IC/BPS therapy and will provide a basis for further development.

• Anatomy and Cell Biology
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• 제56권4호
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• pp.508-517
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• 2023

In cancer patients, chemo/radio therapy may cause infertility by damaging the spermatogenesis affecting the self-renewal and differentiation of spermatogonial stem cells (SSCs). In vitro differentiation of stem cells especially mesenchymal stem cells (MSCs) into germ cells has recently been proposed as a new strategy for infertility treatment. The aim of this study was to evaluate the proliferation and differentiation of SSCs using their co-culture with Sertoli cells and conditioned medium (CM) from adipose tissue-derived MSCs (AD-MSCs). Testicular tissues were separated from 2-7 days old neonate Wistar Rats and after mechanical and enzymatic digestion, the SSCs and Sertoli cells were isolated and cultured in Dulbecco's modified eagle medium with 10% fetal bovine serum, 1X antibiotic, basic fibroblast growth factor, and glial cell line-derived neurotrophic factor. The cells were treated with the CM from AD-MSCs for 12 days and then the expression level of differentiation-related genes were measured. Also, the expression level of two major spermatogenic markers of DAZL and DDX4 was calculated. Scp3, Dazl, and Prm1 were significantly increased after treatment compared to the control group, whereas no significant difference was observed in Stra8 expression. The immunocytochemistry images showed that DAZL and DDX4 were positive in experimental group comparing with control. Also, western blotting revealed that both DAZL and DDX4 had higher expression in the treated group than the control group, however, no significant difference was observed. In this study, we concluded that the CM obtained from AD-MSCs can be considered as a suitable biological material to induce the differentiation in SSCs.

• International Journal of Stem Cells
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• 제15권1호
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• pp.85-94
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• 2022

Background and Objectives: Brain organoids have the potential to improve our understanding of brain development and neurological disease. Despite the importance of brain organoids, the effect of vascularization on brain organoids is largely unknown. The objective of this study is to develop vascularized organoids by assembling vascular spheroids with cerebral organoids. Methods and Results: In this study, vascularized spheroids were generated from non-adherent microwell culture system of human umbilical vein endothelial cells, human dermal fibroblasts and human umbilical cord blood derived mesenchymal stem cells. These vascular spheroids were used for fusion with iPSCs induced cerebral organoids. Immunostaining studies of vascularized organoids demonstrated well organized vascular structures and reduced apoptosis. We showed that the vascularization in cerebral organoids up-regulated the Wnt/β-catenin signaling. Conclusions: We developed vascularized cerebral organoids through assembly of brain organoids with vascular spheroids. This method could not only provide a model to study human cortical development but also represent an opportunity to explore neurological disease.

• International Journal of Stem Cells
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• 제15권1호
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• pp.95-103
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• 2022

Background and Objectives: In recent years, brain organoid technologies have been the most innovative advance in neural differentiation research. In line with this, we optimized a method to establish cerebral organoids from feeder-free cultured human pluripotent stem cells. In this study, we focused on the consistent and robust production of cerebral organoids comprising neural progenitor cells and neurons. We propose an optimal protocol for cerebral organoid generation that is applicable to both human embryonic stem cells and human induced pluripotent stem cells. Methods and Results: We investigated formation of neuroepithelium, neural tube, and neural folding by observing the morphology of embryoid bodies at each stage during the cerebral organoid differentiation process. Furthermore, we characterized the cerebral organoids via immunocytochemical staining of sectioned organoid samples, which were prepared using a Cryostat and Vibratome. Finally, we established a routine method to generate early cerebral organoids comprising a cortical layer and a neural progenitor zone. Conclusions: We developed an optimized methodology for the generation of cerebral organoids using hESCs and hiPSCs. Using this protocol, consistent and efficient cerebral organoids could be obtained from hiPSCs as well as hESCs. Further, the morphology of brain organoids could be analyzed through 2D monitoring via immunostaining and tissue sectioning, or through 3D monitoring by whole tissue staining after clarification.

• 한국과학교육학회지
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• 제34권2호
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• pp.63-78
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• 2014

통합적 STEM 교육은 과학, 기술, 공학, 수학의 내용과 과정을 체계적이고 의도적으로 통합하려는 공학적 설계기반 학습을 말하며, 다른 교과와 통합을 통해 더욱 발달할 수 있다. 이 연구는 과학 탐구 기반의 통합적 STEM 교육 프로그램의 개발과 효과 검증을 위한 기초연구이며, STEM 교육 관련 문헌 연구를 통해 STEM 교육의 가치와 핵심요소를 분석하고 과학 탐구 기반의 통합적 STEM 교육 모형의 개발 및 모형을 적용하여 개발한 대표적인 예시 프로그램을 제시하는 것이다. 모형에 포함될 요소를 확정하기 위해 문헌 분석을 실시하였고, 선행 연구에 포함된 내용과 탐구 과정을 분석하여 통합적 STEM 교육 모형을 구성하였다. 전문가의 내용 타당도 분석 결과 CVR 값의 평균은 0.78로 구성된 모형은 내용 타당도가 있는 것으로 판단되었다. 이 STEM 교육 모형은 내용과 탐구 과정의 두 가지 측면으로 나누어진다. 내용의 측면은 실생활 문제에서 경험할 수 있는 과학, 기술, 공학, 수학 그리고 인문사회와 예술적 소재까지 포괄할 수 있으며, 탐구 과정은 설계와 제작을 기반으로 한 문제해결 과정이다. 탐구 과정은 과학 탐구를 기반으로 하여 기술 공학적 문제해결 과정을 적용할 수 있도록 구성하였다. 학생들은 실생활 문제를 분석하고, 설계하고 제작하는 과정에서 STEM 교과에 대한 흥미를 향상시킬 수 있고 문제에 포함된 지식과 탐구의 방법과 기능을 체계적으로 학습할 수 있다. 개발된 프로그램은 학교 현장에서 활용되어, STEM 교과에 대한 이해도 증진과 과학, 수학에 대한 흥미를 높이고, 과학기술 기반의 융합적 소양과 설계 기반의 문제해결력을 배양하는 데 기여할 수 있을 것이다.

• BMB Reports
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• 제48권2호
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• pp.68-80
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• 2015

G protein-coupled receptors (GPCRs) are a large class of transmembrane receptors categorized into five distinct families: rhodopsin, secretin, adhesion, glutamate, and frizzled. They bind and regulate 80% of all hormones and account for 20-50% of the pharmaceuticals currently on the market. Hundreds of GPCRs integrate and coordinate the functions of individual cells, mediating signaling between various organs. GPCRs are crucial players in tumor progression, adipogenesis, and inflammation. Several studies have also confirmed their central roles in embryonic development and stem cell maintenance. Recently, GPCRs have emerged as key players in the regulation of cell survival, proliferation, migration, and self-renewal in pluripotent (PSCs) and cancer stem cells (CSCs). Our study and other reports have revealed that the expression of many GPCRs is modulated during the generation of induced PSCs (iPSCs) or CSCs as well as during CSC sphere formation. These GPCRs may have crucial roles in the regulation of self-renewal and other biological properties of iPSCs and CSCs. This review addresses the current understanding of the role of GPCRs in stem cell maintenance and somatic reprogramming to PSCs or CSCs.

• 대한공업교육학회지
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• 제36권1호
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• pp.1-22
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• 2011

이 연구의 목적은 중학교 전기전자기술 영역의 활동 중심 STEM 교육프로그램을 개발하고 적용하는데 있었다. 이 통합교육프로그램은 과학, 기술, 공학, 수학 교과의 지식, 기능, 태도와 관련한 현실 세계에서의 문제해결에 초점을 맞추었다. 활동 중심 STEM 교육프로그램 개발은 준비, 개발, 개선의 3단계를 거쳐 진행되었다. 준비단계에서는, (1) STEM 교육프로그램 개발에 대한 학생, 교사, 사회의 요구 분석, (2) STEM 교육프로그램의 통합유형 선정, (3) 전기전자기술 영역의 전문교과 내용 분석, (4) 활동과제 선정 준거를 도출하였다. 개발단계에서는, (1) 전기전자기술 영역 STEM 교육프로그램의 활동과제 선정, (2) 활동과제별 교육목표 설정, (3) 활동분석 및 세부 활동 명료화, (4) 학습 내용 선정, (5) 학습내용 조직, (6) 수업목표 진술, (7) STEM 교육프로그램 내용 구성 및 작성이 이루어졌다. 개선단계에서는, (1) 전문가에 의한 타당도 검증, (2) 학생들에 의한 예비시험과 현장시험을 실행하여 STEM 교육프로그램을 수정 보완하였다. 개발한 활동 중심 STEM 교육프로그램을 S중학교 '방과후학교, 활동에 적용한 결과 학생들의 만족도가 높았으며, 인지적 정의적 영역의 긍정적인 변화가 있었고, 문제해결능력 함양에 긍정적인 효과가 있었다.