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Lee, Seung-Won,Wu, Guangming,Choi, Na Young,Lee, Hye Jeong,Bang, Jin Seok,Lee, Yukyeong,Lee, Minseong,Ko, Kisung,Scholer, Hans R.,Ko, Kinarm Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.7
Spermatogonial stem cells (SSCs) derived from mouse testis are unipotent in regard of spermatogenesis. Our previous study demonstrated that SSCs can be fully reprogrammed into pluripotent stem cells, so called germline-derived pluripotent stem cells (gPS cells), on feeder cells (mouse embryonic fibroblasts), which supports SSC proliferation and induction of pluripotency. Because of an uncontrollable microenvironment caused by interactions with feeder cells, feeder-based SSC reprogramming is not suitable for elucidation of the self-reprogramming mechanism by which SSCs are converted into pluripotent stem cells. Recently, we have established a Matrigel-based SSC expansion culture system that allows longterm SSC proliferation without mouse embryonic fibroblast support. In this study, we developed a new feeder-free SSC self-reprogramming protocol based on the Matrigel-based culture system. The gPS cells generated using a feeder-free reprogramming system showed pluripotency at the molecular and cellular levels. The differentiation potential of gPS cells was confirmed in vitro and in vivo. Our study shows for the first time that the induction of SSC pluripotency can be achieved without feeder cells. The newly developed feeder-free self-reprogramming system could be a useful tool to reveal the mechanism by which unipotent cells are self-reprogrammed into pluripotent stem cells.
Lee, Minseong,Hong, Sungwon,Kim, Dongjae,Kim, Eunjoo,Lim, Kyunghwan,Jung, Jae Chil,Richter, Hannes,Moon, Jong-Ho,Choi, Nakwon,Nam, Jaewook,Choi, Jungkyu American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.4
<P>Chabazite (CHA)-type zeolites are promising for the separation of CO<SUB>2</SUB> from larger molecules, such as N<SUB>2</SUB> (relevant to postcombustion carbon capture) and CH<SUB>4</SUB> (relevant to natural gas/biogas upgrading). In particular, the pore size of CHA zeolites (0.37 × 0.42 nm<SUP>2</SUP>) can recognize slight molecular size differences between CO<SUB>2</SUB> (0.33 nm) and the larger N<SUB>2</SUB> (0.364 nm) or CH<SUB>4</SUB> (0.38 nm) molecules, thus allowing separation in favor of CO<SUB>2</SUB> through CHA membranes. Furthermore, the siliceous constituents in the CHA zeolite can reduce the adsorption capacity toward the smaller H<SUB>2</SUB>O molecule (0.265 nm) and, thus, the H<SUB>2</SUB>O permeation rate. This is highly desirable for securing good molecular sieving ability with CO<SUB>2</SUB> permselectivity in the presence of H<SUB>2</SUB>O vapor. Indeed, a siliceous CHA film obtained with a nominal Si/Al ratio of 100 (CHA_100) showed high CO<SUB>2</SUB>/N<SUB>2</SUB> and CO<SUB>2</SUB>/CH<SUB>4</SUB> separation performance, especially in the presence of H<SUB>2</SUB>O vapor; ∼13.4 CO<SUB>2</SUB>/N<SUB>2</SUB> and ∼37 CO<SUB>2</SUB>/CH<SUB>4</SUB> separation factors (SFs) at 30 °C. These SFs were higher than the corresponding values (∼5.2 CO<SUB>2</SUB>/CH<SUB>4</SUB> SFs and ∼31 CO<SUB>2</SUB>/CH<SUB>4</SUB> SFs) under dry conditions; such improvement could be ascribed to defect blocking by physisorbed water molecules. Finally, the contribution of molecular transport through zeolitic and nonzeolitic parts was quantitatively analyzed by combining information extracted from image processing of fluorescence confocal optical microscopy images with a one-dimensional permeation model. It appears that ∼19 and ∼20% of the total CO<SUB>2</SUB> permeance for CHA_100 were reduced due to transport inhibition by the physisorbed water molecules on the membrane surface and defect, respectively.</P> [FIG OMISSION]</BR>
Kim Minseong,Yeo MyungGu,Lee KyoungHo,Park Min-Jeong,Han Gyeongyeop,Lee Chansong,Park Jihyo,Jung Bongsu 한국조직공학과 재생의학회 2024 조직공학과 재생의학 Vol.21 No.1
Background: Collagen is a key component of connective tissue and has been frequently used in the fabrication of medical devices for tissue regeneration. Human-originated collagen is particularly appealing due to its low immune response as an allograft biomaterial compared to xenografts and its ability to accelerate the regeneration process. Ethically and economically, adipose tissues available from liposuction clinics are a good resource to obtain human collagen. However, studies are still scarce on the extraction and characterization of human collagen, which originates from adipose tissue. The aim of this study is to establish a novel and simple method to extract collagen from human adipose tissue, characterize the collagen, and compare it with commercial-grade porcine collagen for tissue engineering applications. Methods: We developed a method to extract the collagen from human adipose tissue under quasi-Good Manufacturing Practice (GMP) conditions, including freezing the tissue, blood removal, and ethanol-based purification. Various techniques, including protein quantification, decellularization assessment, SDS-PAGE, FTIR, and CD spectroscopy analysis, were used for characterization. Amino acid composition was compared with commercial collagen. Biocompatibility and cell proliferation tests were performed, and in vitro tests using collagen sponge scaffolds were conducted with statistical analysis. Results: Our results showed that this human adipose-derived collagen was equivalent in quality to commercially available porcine collagen. In vitro testing demonstrated high cell attachment and the promotion of cell proliferation. Conclusion: In conclusion, we developed a simple and novel method to extract and characterize collagen and extracellular matrix from human adipose tissue, offering a potential alternative to animal-derived collagen for xeno-free tissue engineering applications. Background: Collagen is a key component of connective tissue and has been frequently used in the fabrication of medical devices for tissue regeneration. Human-originated collagen is particularly appealing due to its low immune response as an allograft biomaterial compared to xenografts and its ability to accelerate the regeneration process. Ethically and economically, adipose tissues available from liposuction clinics are a good resource to obtain human collagen. However, studies are still scarce on the extraction and characterization of human collagen, which originates from adipose tissue. The aim of this study is to establish a novel and simple method to extract collagen from human adipose tissue, characterize the collagen, and compare it with commercial-grade porcine collagen for tissue engineering applications. Methods: We developed a method to extract the collagen from human adipose tissue under quasi-Good Manufacturing Practice (GMP) conditions, including freezing the tissue, blood removal, and ethanol-based purification. Various techniques, including protein quantification, decellularization assessment, SDS-PAGE, FTIR, and CD spectroscopy analysis, were used for characterization. Amino acid composition was compared with commercial collagen. Biocompatibility and cell proliferation tests were performed, and in vitro tests using collagen sponge scaffolds were conducted with statistical analysis. Results: Our results showed that this human adipose-derived collagen was equivalent in quality to commercially available porcine collagen. In vitro testing demonstrated high cell attachment and the promotion of cell proliferation. Conclusion: In conclusion, we developed a simple and novel method to extract and characterize collagen and extracellular matrix from human adipose tissue, offering a potential alternative to animal-derived collagen for xeno-free tissue engineering applications.
NATM 터널의 굴착면 전방 지질 평가를 위한 대구경 심발공 탐사 시스템 개발 및 적용 사례
김민성(Minseong Kim),정진혁(Jinhyeok Jung),이제겸(Jekyum Lee),박민선(Minsun Park),박정현(Jeonghyeon Bak),이승원(Sean Seungwon Lee) 한국암반공학회 2021 터널과지하공간 Vol.31 No.1
최근 도시화가 가속화됨에 따라 지하공간 개발을 위한 굴착공사가 지속적으로 이루어지고 있으며, 암반굴착 시 해당 구간의 지질 상태를 정확히 파악하는 것은 안전한 시공을 위해 매우 중요하다. 본 논문에서는 터널 발파 진동을 저감시키기 위해 대구경 무장약공을 천공하는 MSP 공법을 활용하여 굴착면 전방의 지질 특성을 파악하기 위해 천공경로 및 지반탐사 복합시스템을 개발하였다. 제안된 탐사 시스템은 NATM 터널 공사를 위해 천공된 대구경 심발공을 활용해 굴착면 전방 50 m 구간의 지질 정보를 획득할 수 있다는 큰 장점이 있다. 또한, 제안된 탐사 시스템을 현장에 적용하고 대구경 무장약공 내부를 모니터링하여 터널 굴착면 전방의 지질 상태를 평가한 사례를 소개한다. Recently, the development of underground space has been accelerated with rapid urbanization, and it is significantly important for safe construction to accurately understand the geological conditions of the section when excavating rocks. In this paper, a boring alignment tracking and geological exploration system have been developed to identify the geological conditions beyond the excavation face by utilizing a MSP method that bores a large empty hole to reduce blast-induced vibration. The major advantage of the proposed exploration system is that we can obtain the ground condition of 50 m ahead of the excavation face through exploration along blast cut-holes drilled for the NATM tunnel construction. In addition, we introduce several case histories regarding the assessment of the geological conditions beyond the tunnel face by monitoring the inside of large empty holes using the proposed hole exploration system.