• Journal of Korean Neurosurgical Society
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• v.64 no.5
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• pp.705-715
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• 2021

Objective : Through our previous clinical trials, the demonstrated therapeutic effects of MSC in chronic spinal cord injury (SCI) were found to be not sufficient. Therefore, the need to develop stem cell agent with enhanced efficacy is increased. We transplanted enhanced Wnt3-asecreting human mesenchymal stem cells (hMSC) into injured spines at 6 weeks after SCI to improve axonal regeneration in a rat model of chronic SCI. We hypothesized that enhanced Wnt3a protein expression could augment neuro-regeneration after SCI. Methods : Thirty-six Sprague-Dawley rats were injured using an Infinite Horizon (IH) impactor at the T9-10 vertebrae and separated into five groups : 1) phosphate-buffered saline injection (injury only group, n=7); 2) hMSC transplantation (MSC, n=7); 3) hMSC transfected with pLenti vector (without Wnt3a gene) transplantation (pLenti-MSC, n=7); 4) hMSC transfected with Wnt3a gene transplantation (Wnt3a-MSC, n=7); and 5) hMSC transfected with enhanced Wnt3a gene (1.7 fold Wnt3a mRNA expression) transplantation (1.7 Wnt3a-MSC, n=8). Six weeks after SCI, each 5×10⁵ cells/15 µL at 2 points were injected using stereotactic and microsyringe pump. To evaluate functional recovery from SCI, rats underwent Basso-Beattie-Bresnahan (BBB) locomotor test on the first, second, and third days post-injury and then weekly for 14 weeks. Axonal regeneration was assessed using growth-associated protein 43 (GAP43), microtubule-associated protein 2 (MAP2), and neurofilament (NF) immunostaining. Results : Fourteen weeks after injury (8 weeks after transplantation), BBB score of the 1.7 Wnt3a-MSC group (15.0±0.28) was significantly higher than that of the injury only (10.0±0.48), MSC (12.57±0.48), pLenti-MSC (12.42±0.48), and Wnt3a-MSC (13.71±0.61) groups (p<0.05). Immunostaining revealed increased expression of axonal regeneration markers GAP43, MAP2, and NF in the Wnt3a-MSC and 1.7 Wnt3a-MSC groups. Conclusion : Our results showed that enhanced gene expression of Wnt3a in hMSC can potentiate axonal regeneration and improve functional recovery in a rat model of chronic SCI.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.601-603
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• 2004

Multi-Spectral Camera(MSC) is a payload on the KOMPSAT -2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of $20\%$ over the mission lifetime of 3 years with the functions of programmable gain! offset and onboard image data compression/storage. MSC instrument has one(1) channel for panchromatic Imaging and four(4) channel for multi-spectral Imaging covering the spectral range from 450nm to 900nm using TDI CCD Focal Plane Array (FPA). In this paper, the configuration, the interface of MSC hardware and the MSC operation concept are described. And the method of the MSC calibration are described and the design of MSC calibration operation to measure the change of MSC after Launch & Early Operation(LEOP) and normal mission operations are discussed and analyzed.

• The Journal of the Acoustical Society of Korea
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• v.7 no.2
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• pp.39-50
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• 1988

It is proposed to use a pair of frequency-domain adaptive digital filters to estimate the magnitude squared coherence (MSC) functions of two signals. Such a method requires less computations than the LMS-MSC algorithm in which the least mean square (LMS) algorithm is applied in the time domain to compute the coefficients of a pair of adaptive digital filters. The frequency-domain adaptive digital filtering algorithms considered in this paper include the constrained frequency domain LMS (CFLMS) and the unconstrained frequency domain LMS (UFLMS) algorithms. The performance of the proposed methods are compared with those of the LMS-MSC algorithm.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.60-66
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• 2006

This paper is a study on the coupled load analysis using MSC/Nastran superelement method. After selecting the hunch vehicle, coupled load analysis is performed. From the results of coupled load analysis the loads and displacements on the major parts of satellite structure are calculated Based on the loads and displacements, the safety of satellite structure is judged. Coupled load analysis has been executed using MSC/Nastran DMAP code so far. Because DMAP code was very complicated and long in 1ength it was difficult to analyze and modify the DMAP code. To solve out these problems, coupled load analysis was executed using MSC/Nastran 2005 superelemnt method. At first, satellite FE-model was converted to the Craig-Bampton model using MSC/Nastran 2005 superelement method and verified Finally, coupled load analysis was performed using satellite Craig-Bampton model and launch vehicle FE-model and verified.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.104-104
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• 2003

본 포스터에서는 다목적 위성 2호의 주 탑재체인 MSC(Multi-Spectral Camera)가 TDI(Time Delayed Integration) 방식을 채택함에 따라, TDI에 의해 MSC 영상 자료가 어떻게 영향을 받게 되는 지를 연구한 내용을 설명한다. MSC는 지상 해상도가 1m인 고해상도에서 영상을 촬영하기 때문에 상대적으로 입사 광량이 부족한 문제를 안고 있음에 따라 32 line의 TDI 방식을 사용한다. TDI 방식을 사용하여 MSC에서 직하방향으로 영상을 촬영할 경우, 영상의 가운데 pixel에서 멀어질수록 TDI에 의해 영상의 MTF 값이 떨어지는 결과가 발생한다. 또한, 다목적 위성 2호는 Roll 축을 중심으로 $\pm$30도 Pitch 축을 중심으로 $\pm$30도 tilt를 하여 영상을 촬영하도록 운영될 예정이기 때문에 더더욱 TDI에 의채 영상의 MTF 값이 떨어지는 결과가 발생하게 된다. 이외에도 TDI는 다목적 위성 2호의 고도가 감소하거나, Yaw 축의 변화, Jitter 등에 의해서도 영상의 MTF 값이 감소하게 된다. 물론 MSC CCD pixel의 sampling rate인 Line Rate 값을 각각의 경우에 따라 적절한 값을 부여함으로써 TDI에 의한 MTF 값의 감소를 많은 부분은 수습할 수 있으나 완벽한 보정은 힘든 상황이다.

• Journal of the military operations research society of Korea
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• v.28 no.2
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• pp.1-19
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• 2002

This study shows the effect of inventory policy change from supplier-based to customer-based. We focus on the service level, cost, and information distortion of the Military Supply Chain(MSC) with System Dynamics. We design MSC model according to field practician interviews by using Vensim. The simulation makes a comparison between supply-based inventory policy performances and order-based inventory policy performances. In order to evaluate the MSC performances, we measure the accumulation of backlog(service level), supply chain cost, and order percentage overshoot(information distortion). The results show that 1) changing inventory policy from supplier-based to end customer order-based gets a good customer service, reduces MSC cost, and prevents information distortion, 2) changing inventory policy from supplier-based to immediate customer order-based reduces a small amount of MSC cost and deteriorates customer service, and 3) supply level is main factor for MSC performances improvement. This study implicates the policy change makes a improvement of MSC performance without introducing information system.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.3
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• pp.215-222
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• 2020

Mesenchymal stem cells (MSCs) have been widely used as donor cells for somatic cell nuclear transfer (SCNT) to increase the efficiency of embryo cloning. Since replicative senescence reduces the efficiency of embryo cloning in MSCs during in vitro expansion, transfection of telomerase reverse transcriptase (TERT) into MSCs has been used to suppress the replicative senescence. Here, TERT-transfected MSCs in comparison with early passage MSCs (eMSCs) and sham-transfected MSCs (sMSCs) were used to evaluate the effects of embryo cloning with SCNT in a porcine model. Cloned embryos from tMSC, eMSC, and sMSC groups were indistinguishable in their fusion rate, cleavage rate, total cell number, and gene expression levels of OCT4, SOX2 and NANOG during the blastocyst stage. The blastocyst formation rates of tMSC and sMSC groups were comparable but significantly lower than that of the eMSC group (p < 0.05). In contrast, tMSC and eMSC groups demonstrated significantly reduced apoptotic incidence (p < 0.05), and decreased BAX but increased BCL2 expression in the blastocyst stage compared to the sMSC group (p < 0.05). Therefore, MSCs transfected with telomerase reverse transcriptase do not affect the overall development of the cloned embryos in porcine SCNT, but enables to maintain embryo quality, similar to apoptotic events in SCNT embryos typically achieved by an early passage MSC. This finding offers a bioengineering strategy in improving the porcine cloned embryo quality.

• IMMUNE NETWORK
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• v.4 no.2
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• pp.88-93
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• 2004

Background: Bone marrow mesenchymal stem cells (MSC) inhibit the immune response of lymphocytes to specific antigens and dendritic cells (DC) are professional antigenpresenting cells whose function is to present antigen to naive T-lymphocytes with high efficiency and play a central role in the regulation of immune response. We studied the effects of MSC on DC to evaluate the relationship between MSC and DC in transplantation immunology. Methods: MSC were expanded from the bone marrow and DC were cultured from peripheral blood mononuclear cells (PBMNC) of 6 myelogenous leukemia after achieving complete response. Responder cells isolated from PBMNC and lysates of autologous leukemic cells are used as tumor antigen. The effect of MSC on the DC was analyzed by immunophenotype properties of DC and by proliferative capacity and the amount of cytokine production with activated PBMNC against the allogeneic lymphocytes. Also, cytotoxicity tests against leukemic cells studied to evaluate the immunologic effect of MSC on the DC. Results: MSC inhibit the CD83 and HLA-class II molecules of antigen-loaded DC. The proliferative capacity and the amount of INF-$\gamma$ production of lymphocytes to allogeneic lymphocytes were decreased in DC co-cultured with MSC. Also the cytotoxic activity of lymphocytes against leukemic cells was decreased in DC co-cultured with MSC. Conclusion: MSC inhibit the activation and immune response of DC induced by allogeneic or tumor antigen.

• Molecules and Cells
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• v.39 no.4
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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.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.394-400
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• 2008

Purpose: Quantitative comparison of transgene expression within stem cells between lentivirus and adenovirus-mediated delivery systems has not been reported. Here, we evaluated the human sodium iodide symporter (hNIS) gene expression in rat mesenchymal stem cell (rMSC) transduced by lentivirus or adenovirus, and compared the hNIS expression quantitatively between the two delivery systems. Materials and Methods: Lentiviral-mediated hNIS expressing rMSC (lenti-hNIS-rMSC) was constructed by cloning hNIS gene into pLenti6/UbC/V5-DEST (Invitrogen) to obtain pLenti-hNIS, transducing rMSC with the pLenti-hNIS, and selecting with blasticidin for 3 weeks. Recombinant adenovirus expressing hNIS gene (Rad-hNIS) was produced by homologous recombination and transduction efficiency of Rad-hNIS into rMSC evaluated by Rad-GFP was $19.1{\pm}4.7%$, $54.0{\pm}6.4%$, $85.7{\pm}8.7%$, and $98.4{\pm}1.3%$ at MOI 1, 5, 20, and 100, respectively. The hNIS expressions in lenti-hNIS-rMSC or adeno-hNIS-rMSC were assessed by immunocytochemistry, western blot, and 1-125 uptake. Results: Immunocytochemistry and western blot analyses revealed that hNIS expressions in lenti-hNIS-rMSC were greater than those in adeno-hNIS-rMSC at MOI 20 but lower than at MOI 50. However in vitro 1-125 uptake test demonstrated that iodide uptake in lenti-hNIS-rMSC ($29,704{\pm}6,659\; picomole/10^6\;cells$) was greater than that in adeno-hNIS-rMSC at MOI 100 ($6,168{\pm}2,134\;picomole/10^6\;cells$). Conclusion: Despite lower amount of expressed protein, hNIS function in rMSC was greater by lentivirus than by adenovirus mediated expression. Stem cell tracking using hNIS as a reporter gene should be conducted in consideration of relative vector efficiency for transgene expression.