• 생명과학회지
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• 제28권9호
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• pp.1042-1047
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• 2018

홍조류인 꼬물꼬시래기(Gracilaria vermiculophylla)는 전 세계의 해변 지역에 널리 퍼져 있으며 아시아 국가에서 식량 자원으로 이용되어왔다. 이전 연구에 따르면, Gracilaria 속 홍조류 추출물에서 항산화 및 항염증 효과가 보고 되었다. 본 연구에서는 노화된 인간의 골수 유래 중간엽 줄기세포(hBM-MSCs)를 이용하여 Gracilaria vermiculophylla 추출물(GV-Ex)의 항노화 효과를 조사하였다. MTT 분석와 immunoblot 분석(apoptotic protein p53과 cleaved caspase-3)을 이용하여, GV-Ex 전처리는 산화적 스트레스에 의해 손상된 hBM-MSCs의 세포생존력을 향상시킴을 확인하였다. 또, 세포내 생성된 ROS는 장기간 배양 된 MSCs (Passages 17; P-17)와 P-7 MSC에서 측정하여 서로 비교하였는데, P-17 MSC에서 증가되었고, GV-Ex 처리하면(GV-Ex treated P-17 MSCs) 유의하게 감소되었다. 또한, 항산화 효소인 SOD1와 SOD2, CAT의 발현 역시 GV-Ex 처리함에 따라 복원됨을 관찰하였다. 노화 표지단백질인 p53와 p21, p16 등의 발현 또한 GV-Ex를 처리한 P-17 MSC에서 감소되었다. 줄기세포의 골세포(osteocytes) 혹은 지방세포(adipocytes)로 분화하는 능력 역시 GV-Ex를 처리한 P-17 MSCs에서 개선되었다. 이상과 같은 결과를 통해, GV 추출물은 노화된 줄기세포의 기능을 개선함을 시사한다.

• Molecules and Cells
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• 제39권4호
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• pp.337-344
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• 2016

Intravenous administration of mesenchymal stem cells (IV-MSC) protects the ischemic rat brain in a stroke model, but the molecular mechanism underlying its therapeutic effect is unclear. We compared genomic profiles using the mRNA microarray technique in a rodent stroke model. Rats were treated with $1{\times}10^6$ IV-MSC or saline (sham group) 2 h after transient middle cerebral artery occlusion (MCAo). mRNA microarray was conducted 72 h after MCAo using brain tissue from normal rats (normal group) and the sham and MSC groups. Predicted pathway analysis was performed in differentially expressed genes (DEGs), and functional tests and immunohistochemistry for inflammation-related proteins were performed. We identified 857 DEGs between the sham and normal groups, with the majority of them (88.7%) upregulated in sham group. Predicted pathway analysis revealed that cerebral ischemia activated 10 signaling pathways mainly related to inflammation and cell cycle. IV-MSC attenuated the numbers of dysregulated genes in cerebral ischemia (118 DEGs between the MSC and normal groups). In addition, a total of 218 transcripts were differentially expressed between the MSC and sham groups, and most of them (175/218 DEGs, 80.2%) were downregulated in the MSC group. IV-MSC reduced the number of Iba-$1^+$ cells in the peri-infarct area, reduced the overall infarct size, and improved functional deficits in MCAo rats. In conclusion, transcriptome analysis revealed that IV-MSC attenuated postischemic genomic alterations in the ischemic brain. Amelioration of dysregulated inflammation- and cell cycle-related gene expression in the host brain is one of the molecular mechanisms of IV-MSC therapy for cerebral ischemia.

• 한국임상수의학회지
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• 제28권4호
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• pp.399-402
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• 2011

In recent years, the mesenchymal stem cells (MSC) derived from various tissues have been widely tested for developing cell therapies, tissue repair and transplantation. Although there has been much interest in the immunomodulatory properties of MSC and their immunologic reactions following autologous, allogeneic and xenogenic transplantation of MSC in vivo, up to date, the expression of immunogenic markers, such as class I and II human leukocyte antigens (HLA), after differentiation of human umbilical cord blood (hUCB)-derived MSC has been poorly investigated and require extensive in vitro and in vivo testing. In this experiment, the expression of the HLA-ABC and HLA-DR on hUCB-derived MSC have been tested by immunocytochemical staining. The undifferentiated MSC were moderately stained for HLA-ABC but very weakly for HLA-DR. In order to investigate the inhibitory effect of allogeneic lymphocytes on proliferation of MSC, the MSC were cultured in the presence or absence of peripheral allogeneic lymphocytes stimulated with concanavalin A. The allogeneic lymphocytes did not significantly inhibit MSC proliferation. We conclude that hUCB-MSC expressed moderately class I HLA antigen while almost negatively class II HLA antigen. The MSC have an immunomodulatory effect which can suppress the allogeneic response of lymphocytes. These in vitro data suggest that allogeneic MSC derived from cord blood can be useful candidate for allogeneic cell therapy and transplantation without a major risk of rejection.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.448-451
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• 2004

MSC (Multi-Spectral Camera) system is an electro-optical camera system which is being developed to be installed on KOMPSAT-2 satellite. High resolution image data from MSC system will be transmitted to the ground-station through x-band antenna called APS (Antenna Pointing System). APS is a directional antenna which will point to the receiving antenna at ground station while the satellite is passing over it. The APS needs to be controlled accurately to provide the reliable communication with big RF link margin. The APS is controlled by ATS (Antenna Tracking Software) which is included in the MSC software. ATS uses the closed loop control algorithm which will use TPF (Tracking Parameter File) as an input for antenna position, and will use two resolve readings from APS as a feedback. ATS has been developed and verified using APS QM (Qualification Model) and all the control parameters for ATS have been tested and verified. Various kinds of maximum, nominal and realistic dynamics for the APS movement have been simulated and verified. In this paper, closed loop servo control algorithm and obtained APS position error from the verification test with APS QM will be presented in detail

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1096-1098
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• 2003

SBC(Single Board Computer) is being developed for MSC(Multi-Spectral Camera) on KOMPSAT-2(Korea Multi-Purpose Satellite). SBC controls all the units of MSC system and gets commands and sends telemetry to and from spacecraft bus via 1553 communication channel. Due to the fact that SBC does very important roles for MSC system operation and SBC operates with 100% duty cycle, SBC is designed to have high reliability. SBC which has Intel 80486 as a main processor includes eight serial communication channels, one mil-std-1553 interface channel and several discrete interfaces. SBC incorporates 2Mbyte radiation hardened SRAM(Static Random Access Memory) and 1Mbyte flash memory. There are also PIC(Programmable Interrupt Controller), counter, WDT(Watch Dog Timer) in the SBC. In this paper, the design result of the SBC is presented.

• 한국음향학회지
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• 제7권2호
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• pp.39-50
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• 1988

한 쌍의 주파수 영역 적응 디지탈 필터를 이용하여 두 신호간의 magnitude squared coherence(MSC) 함수를 추정하는 방법을 제안하였다. 이와 같은 방법은 시간 영역에서 한 쌍의 적응디지탈 필터를 이용하는 LMS-MSC(least mean square-MSC)알고리즘에 비하여 적은 양의 계산으로 MSC 함수를 구할 수 있다. MSC함수 추정을 위하여 대표적인 주파수 영역 적응 필터링 알고리즘인 CFLMS(constrained frequency-domain LMS)와 UFLMS (unconstrained frequency-domain LMS)알고리즘을 사용하였으며, 컴퓨터 시뮬레이션을 통하여 LMS-MSC 알고리즘과 성능을 비교하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1108-1110
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• 2003

MSC(Multi-Spectral Camera) which is a unique payload for KOMPSAT-2, comprises main three subsystems of PMU(Paylaod Management Unit), EOS(Electro -Optical Subsystem) and PDTS(Payload Data Transmission Subsystem). The PMU, as a main controller of MSC, performs major tasks such as interfacing with S/C(Space Craft), controlling the MSC operation, distributing and controlling of operating power to all MSC including thermal unit, etc. In this paper the H/W configurations as well as the functions of PMU are introduced and possible changes for the future development are suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.449-450
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• 2012

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.507-512
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• 2001

In this work, tool holder system has been designed and builted to measure cutting forces in diamond turning. This system design includes a 3-component piezo-electric tranducer. Initial experiments with tool holder system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. Tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. Many cutting experiments have been conducted on 6061-T6 aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool force. Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces.

• Molecules and Cells
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• 제44권8호
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• pp.580-590
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• 2021

Patients with severe asthma have unmet clinical needs for effective and safe therapies. One possibility may be mesenchymal stem cell (MSC) therapy, which can improve asthma in murine models. However, it remains unclear how MSCs exert their beneficial effects in asthma. Here, we examined the effect of human umbilical cord blood-derived MSCs (hUC-MSC) on two mouse models of severe asthma, namely, Alternaria alternata-induced and house dust mite (HDM)/diesel exhaust particle (DEP)-induced asthma. hUC-MSC treatment attenuated lung type 2 (Th2 and type 2 innate lymphoid cell) inflammation in both models. However, these effects were only observed with particular treatment routes and timings. In vitro co-culture showed that hUC-MSC directly downregulated the interleukin (IL)-5 and IL-13 production of differentiated mouse Th2 cells and peripheral blood mononuclear cells from asthma patients. Thus, these results showed that hUC-MSC treatment can ameliorate asthma by suppressing the asthmogenic cytokine production of effector cells. However, the successful clinical application of MSCs in the future is likely to require careful optimization of the route, dosage, and timing.