• Journal of the Korean Wood Science and Technology
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• 제39권5호
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• pp.406-419
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• 2011

This study was carried out to offer basic information on the wood anatomy of domestic yellow-poplar (Liriodendron tulipifera L.), a new plantation species selected by Korea Forest Service as one of the promising hardwood and bioenergy sources of the future, through comparison of stem wood with root wood in the qualitative and quantitative features. In the qualitative anatomical features, growth rings were distinct in stem wood but relatively less distinct in root wood. And stem wood appeared to have pores in radial multiples of 2 to 5, sometimes clusters but root wood to have pores in radial multiples of 2 to 3, rarely clusters. And numbers of bars in scalariform perforation plates were somewhat numerous in vessel elements of root wood than in those of stem wood. Interestingly, on the other hand, more extraneous materials in the wood rays of tap root than in those of lateral root and stem were confirmed in the chemical composition analyses. In the quantitative anatomical features, pore densities were significantly greater but vessel elements were considerably narrower in stem wood than in root wood. Vessel elements and wood fibers of root wood were considerably longer than those of stem wood. Rays were somewhat more numerous in stem wood than in root wood, and only ray heights of stem wood were more or less greater in cell numbers but both ray heights and widths of stem wood were lower in dimension than those of root wood. The anatomical differences between stem wood and root wood were thought to be associated with different growth environments between the stem above ground and the root below ground.

• Journal of Ginseng Research
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• 제30권3호
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• pp.132-136
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• 2006

인삼에 있어 다경 및 잠아 발생형태가 원료삼 및 홍삼 품질에 미치는 영향을 구명하고자 지하부 특성 및 품질요인을 조사하였다. 단경개체는 1-3개의 잠아를 갖는 형태이고 2경개체는 2-3개 그리고 3경개체는 3개의 잠아를 갖는 형태이었다. 또한 단경개체는 62.9% 그리고 2경 이상의 다경개체는 37.1%의 분포를 나타냈다. 원료삼의 등급은 단경개체에 비하여 다경개체가 될 수록 저하하였고 단경개체와 다경개체 모두 잠아수가 많은 개체에서 등급이 낮았다. 경수에 따른 홍삼수율은 대체로 30% 내외로 단경이나 다경개체간에 큰 차이가 없었다. 그러나 본삼수율은 다경개체로 갈수록 감소하는 경향이었다. 홍삼 등급은 다경개체에 비해 단경개체가 양호하였으며 다경개체는 양삼과 잡삼이 많았다. 그리고 잠아수가 많을수록 홍삼등급은 저하하였다.

• The Korean Journal of Pain
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• 제32권4호
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• pp.245-255
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• 2019

Stem cells are attracting attention as a key element in future medicine, satisfying the desire to live a healthier life with the possibility that they can regenerate tissue damaged or degenerated by disease or aging. Stem cells are defined as undifferentiated cells that have the ability to replicate and differentiate themselves into various tissues cells. Stem cells, commonly encountered in clinical or preclinical stages, are largely classified into embryonic, adult, and induced pluripotent stem cells. Recently, stem cell transplantation has been frequently applied to the treatment of pain as an alternative or promising approach for the treatment of severe osteoarthritis, neuropathic pain, and intractable musculoskeletal pain which do not respond to conventional medicine. The main idea of applying stem cells to neuropathic pain is based on the ability of stem cells to release neurotrophic factors, along with providing a cellular source for replacing the injured neural cells, making them ideal candidates for modulating and possibly reversing intractable neuropathic pain. Even though various differentiation capacities of stem cells are reported, there is not enough knowledge and technique to control the differentiation into desired tissues in vivo. Even though the use of stem cells is still in the very early stages of clinical use and raises complicated ethical problems, the future of stem cells therapies is very bright with the help of accumulating evidence and technology.

• Journal of Medicine and Life Science
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• 제15권2호
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• pp.46-50
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• 2018

Cancer, a leading mortality disease following cardiovascular disease worldwide, has high incidence as one out of every four adults in Korea. It was known to be caused by several reasons including somatic mutation, activation of oncogene and chromosome aneuploidy. Cancer cells show a faster growth rate and have metastatic and heterogeneous cell populations compared to normal cells. Cancer stem cells, the most invested field in cancer biology, is a theory to explain heterogeneous cell populations of cancer cells among several characteristics of cancer cells, which is providing the theoretical background for incidence of cancer and treatment failure by drug resistance. Cancer stem cells initially explain heterogeneous cell populations of cancer cells based on the same markers of normal stem cells in cancer, in which only cancer stem cells showed heterogeneity of cancer cells and tumor initiating ability of leukemia. Based on these results, cancer stem cells were reported in various solid cancers such as breast cancer, liver cancer, and lung cancer. Breast cancer stem cells were first reported in solid cancer which had tumor initiating ability and further identified as anti-cancer drug resistance. There were several identification methods in breast cancer stem cells such as specific surface markers and culture methods. The discovery of cancer stem cells not only explains heterogeneity of cancer cells, but it also provides theoretical background for targeting cancer stem cells to complete elimination of cancer cells. Many institutes have been developing new anticancer drugs targeting cancer stem cells, but there have not been noticeable results yet. Many researchers also reported a necessity for improvement of current concepts and methods of research on cancer stem cells. Herein, we discuss the limitations and the perspectives of breast cancer stem cells based on the current concept and history.

• International Journal of Stem Cells
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• 제16권1호
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• pp.44-51
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• 2023

Background and Objectives: DNA methyltransferases (Dnmts) play an important role in regulating DNA methylation during early developmental processes and cellular differentiation. In this study, we aimed to investigate the role of Dnmts in neural differentiation of embryonic stem cells (ESCs) and in maintenance of the resulting neural stem cells (NSCs). Methods and Results: We used three types of Dnmt knockout (KO) ESCs, including Dnmt1 KO, Dnmt3a/3b double KO (Dnmt3 DKO), and Dnmt1/3a/3b triple KO (Dnmt TKO), to investigate the role of Dnmts in neural differentiation of ESCs. All three types of Dnmt KO ESCs could form neural rosette and differentiate into NSCs in vitro. Interestingly, however, after passage three, Dnmt KO ESC-derived NSCs could not maintain their self-renewal and differentiated into neurons and glial cells. Conclusions: Taken together, the data suggested that, although deficiency of Dnmts had no effect on the differentiation of ESCs into NSCs, the latter had defective maintenance, thereby indicating that Dnmts are crucial for self-renewal of NSCs.

• 한국과학교육학회지
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• 제32권1호
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• pp.30-45
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• 2012

전세계의 교육공동체들은 STEM (Science, Technology, Engineering, and Mathematics) 과목들을 통합하려는 노력에 주목해오고 있다. 우리나라에서도 또한 과학기술 인재 양성을 위해 초 중등학교에서 과학기술학, 예술, 수학교육(STEAM)을 융합형으로 가르치는 교육을 강조하고 있다. 이 연구의 목적은 과학, 기술, 수학교사를 대상으로 하여 중등학교에서 이루어지고 있는 통합교육의 현황과 통합 STEM 교육(Integrative STEM Education)에 대한 교사들의 인식과 요구를 분석하는 것이다. 전국 중등교사 중 과학, 수학, 기술 교과를 담당하는 251명을 대상으로 설문조사를 하였으며, 연구 결과는 다음과 같다. 첫째, 교사들은 통합 교육의 필요성에 대하여 긍정적인 생각을 가지고 있는 반면 실제 교육현장에서는 통합 교육 준비에 대한 불충분한 시간과 통합 교육에 대한 전문성, 교수경험 그리고 교수-학습 자료의 부족으로 통합 교육을 실시해 본 횟수는 적었다. 둘째, 그들은 통합 교육을 활성화하기 위하여 다양한 프로그램 개발, 통합 교육 준비를 위한 학교의 행 재정적 지원, 그리고 교사들을 위한 연수 실시 등을 요구하였다. 셋째, 통합 STEM 교육에 대한 인식은 전반적으로 불충분하지만 교사들은 학생들의 창의력, 사고력과 실생활에서의 적용 및 응용력을 기르기 위해 통합 STEM 교육이 필요하다고 인식하였다. 넷째, 교사들은 통합 STEM 교육 프로그램 개발, 교수-학습 자료의 보급을 시급한 과제로 생각하고 있다. 다섯째, 교사들은 통합 STEM 교육 프로그램에 적합한 통합 방식은 문제해결중심의 통합 방식으로 나타났다. 아울러, 통합 STEM 교육이 통합적 문제 해결과 담당 교과의 소양 함양에 효과적이라고 생각하며, 과학기술 인재 양성에 영향을 많이 줄 것이라고 생각하고 있었다. STEM 관련 중등교사들의 통합 STEM 교육에 대한 인식을 높이고, 통합 STEM 교육을 활성화하기 위해서 학교 현장을 중심으로 교사의 요구가 반영된 프로그램, 다양한 교수 학습 자료의 보급, 그리고 관련 연수들이 필요하다.

• 한국작물학회지
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• 제62권1호
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• pp.60-65
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• 2017

이 시험은 '솔라라' 품종의 종자생산을 위해 분무경 수경재배에 적합한 묘를 구명하고자 2015년 3월 16일 배양순화묘 등 8처리의 묘를 분무경 베드에 정식하여 정식 후 70, 78일에 각각 생육과 수량특성을 조사하였다. 경장은 경삽 15일묘와 배양순화묘가 작은 편이었고 경삽묘의 육묘일수가 늘어남에 따라 길어지는 경향이었다. 생체중도 경삽 40일묘가 주당 122 g으로 가장 무거웠고 무발근묘와 배양순화묘는 가장 가벼웠다. 1차 복지는 경삽 35일묘에서 주당 12.9개로 가장 많았고 2차 복지는 경삽 35일묘, 배양순화묘, 경삽 30일묘에서 많이 발생하였다. 10주당 총괴경수는 배양순화묘가 145개로 많았으나 3~50 g(상품) 괴경수는 경삽 35일묘가 108개로 가장 많았고, 괴경 무게는 경삽 35일묘가 1,947 g으로 가장 무거웠고 다음으로 경삽 30일묘였다. '솔라라' 품종 수경재배 시에는 경삽한 후 30일~35일(경장 15 cm, 마디 12절) 묘로 정식하는 것이 수량성을 높일 수 있었다.

• 대한화장품학회지
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• 제49권2호
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• pp.169-176
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• 2023

본 연구는 알로에 형성층으로부터 유도된 캘러스에서 줄기세포를 추출하고, 이에 대한 항산화 활성 및 피부 탄력 개선효과를 확인하고자 하였다. 알로에 형성층 유래 줄기세포 추출물 AloStem과 캘러스의 세포 생존율을 확인한 결과, AloStem은 98.27%, 캘러스는 71.31%의 세포가 생존하는 것으로 확인되었다. AloStem의 DPPH 항산화 활성을 측정한 결과, 알로에 추출물보다 AloStem에서 2 배 이상의 항산화 효과를 가지는 것으로 확인되었다. AloStem이 함유된 겔에 대한 인간진피섬유아세포의 독성을 확인한 결과, 0.25% 농도까지 영향을 미치지 않았으며, elastin, COL1A1 및 HAS2 mRNA 발현량을 증가시켰다. 또한, AloStem이 함유된 시트마스크를 이용하여 피부탄력 리프팅 효과에 대한 임상적 연구를 성인남녀 21 명을 대상으로 2 주간 진행한 결과, 피부 길이가 시트마스크 사용 전에는 116.75 ± 5.58 mm로 나타났으나, 2 주 사용 후에는 117.44 ± 5.17 mm 로 0.59%가 증가된 것으로 확인되어 AloStem을 함유한 시트마스크는 탄력 개선에 의한 리프팅 효과에 도움을 주는 것으로 최종 확인되었다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.245-248
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• 1997

Excessive stress on the bone-stem interface may cause local micromotion that could produce midthigh pain, interface bone resorption and prevent bony ingrowth. It is important for clinician and prosthetic designer to develop an understanding of the load transfer mechanism, its associated stress pattern and its relationships with the particular mechanical characteristics of the femoral stem designs. Finite element method (FEM) is preeminently suited to provide information in this respect. The authors developed 3-dimensional numerical finite element models implanted with the straight stem which is composed of total 1170 elements of 8 nodes and with the curved stem which is composed of total 885 elements of 8 node, and analysed the relative micromotions between the straight stem and the curved stem in immediate postoperative stage of an uncemented total hip replacement in load simulating the single leg stance. The results showed that the rotational displacement was occupied over 90% of total micromotion in both types of stem and was peak at the proximal medial portion of the stem, but markedly less distally. The curved stem was more stable especially in terms of rotational stability. It is recommended that surgeons do not allow the patient weight bearing until bony ingrowth was achieved. In the future more attention should be drawn to increase initial rotational stability of the two types of femoral stem to prevent loosening from excessive micromotion.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권2호
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• pp.133-141
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• 2008

Stem cells have self-renewal capacity, long-term viability, and multiline age potential. Adult bone marrow contains mesenchymal stem cells. Bone marrow-derived mesenchymal stem cells (BMSCs) are progenitors of skeletal tissue components and can differentiate into adipocytes, chondrocytes, osteoblasts, and myoblasts in vitro and undergo differentiation in vivo. However, the clinical use of BMSCs has presented problems, including pain, morbidity, and low cell number upon harvest. Recent studies have identified a putative stem cell population within the adipose tissue. Human adipose tissue contains pluripotent stem cells simillar to bone marrow-derived stem cells that can differentiate toward the osteogenic, adipogenic, myogenic, and chondrogenic lineages. Human adipose tissue-derived stem cells (ATSCs) could be proposed as an alternative source of adult bone marrow stem cells, and could be obtained in large quantities, under local anesthesia, with minimal discomfort. Human adipose tissue obtained by liposuction was processed to obtain ATSCs. In this study, we compared the osteogenic differentiation of ATSCs in a specific osteogenic induction medium with that in a non-osteogenic medium. ATSCs were incubated in an osteogenic medium for 28 days to induce osteogenesis respectively. Osteogenic differentiation was assessed by von Kossa and alkaline phosphatase staining. Expression of osteocyte specific bone sialoprotein, osteocalcin, collagen type I and alkaline phosphatase, bone morphogenic protein 2, bone morphogenic protein 6 was confirmed by RT-PCR. ATSCs incubated in the osteogenic medium were stained positively for von Kossa and alkaline phosphatase staining. Expression of osteocyte specific genes was also detected. Since this cell population can be easily identified through fluorescence microscopy, it may be an ideal source of ATSCs for further experiments on stem cell biology and tissue engineering. The present results show that ADSCs have an ability to differentiate into osteoblasts. In the present study, we extend this approach to characterize adipose tissue-derived stem cells.