• Computational Structural Engineering
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• v.9 no.3
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• pp.75-80
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• 1996

본 고에서는 자동차, 항공, 전자, 중고업 및 건설 등의 분야에 널리 사용이 가능한 MSC/NASTRAN의 개략적인 기능을 살펴보고자 한다.

• Journal of Korean Neurosurgical Society
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• v.57 no.5
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• pp.323-328
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• 2015

Objective : Malignant gliomas are the most common primary tumors of the central nervous system and the prognosis of patients with gliomas is poor. The combination of interferon-bata (IFN-${\beta}$) and temozolomide (TMZ) has shown significant additive antitumor effects in human glioma xenograft models. Considering that the poor survival of patients with human malignant gliomas relates partly to the inability to deliver therapeutic agents to the tumor, the tropism of human bone marrow-derived mesenchymal stem cells (MSC) for malignant gliomas can be exploited to therapeutic advantages. We investigated the combination effects of TMZ and MSCs that secrete IFN-${\beta}$ on gliomas. Methods : We engineered human MSCs to secret mouse IFN-${\beta}$ (MSC-IFN-${\beta}$) via adenoviral transduction and confirmed their secretory capacity using enzyme-linked immunosorbent assays. In vitro and in vivo experiments were performed to determine the effects of the combined TMZ and MSC-IFN-${\beta}$ treatment. Results : In vitro, the combination of MSC-IFN-${\beta}$ and TMZ showed significantly enhanced antitumor effects in GL26 mouse glioma cells. In vivo, the combined MSC-IFN-${\beta}$ and TMZ therapy significantly reduced the tumor size and improved the survival rates compared to each treatment alone. Conclusion : These results suggest that MSCs can be used as an effective delivery vehicle so that the combination of MSC-IFN-${\beta}$ and TMZ could be considered as a new option for the treatment of malignant gliomas.

• Journal of Periodontal and Implant Science
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• v.34 no.1
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• pp.93-100
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• 2004

많은 연구들에서 hMSC를 얻기 위해 centrifugation, fluoroscence activated cell sorter(FACS), magnetic activated cell sorter(MACS)가 이용되어져 왔다. 그러나 centrifugation만을 이용한 경우 순도가 떨어지며 FACS나 MACS의 경우에는 비용, 시간이 많이 드는 단점이 있다. 따라서 이 연구에서는 antibody cocktail을 이용하여 hMSC를 좀더 쉽게 얻어내는 방법에 대해 알아보았다. 사람의 골반에서 12G의 바늘을 이용하여 골수를 흡입한 후 heparin이 들어있는 시험관에 넣고 처리과정을 시행하기 전에 냉장고에 보관하며 가능한 한 빨리 처리 과정을 실시한다. 얻은 골수에 적당량의 RosetteSep( Stemcell Technologies)을 첨가한 후 실온에서 20분간 반응시킨다. 그 후 적당량의 Ficoll-paque위에 골수와 RosetteSep의 혼합물을 섞이지 않게 올리고 원심분리를 이용하여 원하는 세포층을 얻어낸다. 이 세포층을 따로 분리한 뒤 배양한다. 배양 시 세포가 80%이상 차기 전에 계속 passage를 시행하며 배양한다. 이는 세포가 밀도가 높아져 원치 않는 세포로 분화되는 것을 막기 위함이다. 배양된 세포가 다양한 분화능력을 가지고 있는지 알아보기 위해 세 가지로 분화를 유도하였다. 적절한 배지와 적절한 환경에서 배양함으로써 얻어진 세포를 osteoblast, chondroblast, adipocyte로 분화를 유도하였다. 분화된 세포가 원하는 형질의 세포로 분화되었는지를 확인하기 위하여 osteoblast의 경우 alizarin red staining, alkaline phosphatase activity, chondroblast의 경우 toluidine blue staining, adipocyte의 경우 Oil-Red-O staining으로 염색하여 분화를 확인하였다. 분리해낸 세포는 각각 세 가지 세포로 분화가 되었으며 이는 RosetteSep이 hMSC를 성공적으로 분리해냈다는 것을 보여준다. 그러나 모든 세포가 분화를 보이지는 않았으며 따라서 hMSC의 순도를 높이기 위한 연구가 더 필요하다. RosetteSep을 이용하면 다른 방법들 보다 쉽게 hMSC를 얻을 수 있으나 기존의 방법과 순도의 측면에서 더 비교할 필요가 있다.

• The Korean Journal of Food And Nutrition
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• v.27 no.2
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• pp.267-273
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• 2014

This study found antibacterial activity of $DMfree^{(R)}$ [green tea extract] on facultative bacteria by direct petri dish method and gene array of obligatory M. leprae infected mesenchymal stem cells (MSC). While DMfree showed DPPH radical scavenging effect and high contents of polyphenol, it did not inhibit growth of facultative bacteria such as E. coli and S. aureus on the petri dish. The result does not exclude a possible antibacterial effect of organic solvent extract of green tea rather than DMfree which comes from the water extract of green tea. Pre-treatment of DMfree appeared to have no effect on copy number of 14 genes compared with control MSC by real-time RT-PCR. However pre-treatment of DMfree on M. leprae infected MSC revealed a significant decrease of anti-inflammatory cytokine (IL-6), (P<0.038) and sharp down-regulation of pro-inflammatory cytokine (IL-1). Enhanced expression of VEGFR-1 mRNA was noted in DMfree pretreated M. leprae infected MSC group (P<0.003). These results show that DMfree would stabilize M. leprae infected MSC from further inflammation by down-regulating anti-inflammatory cytokine (IL-6) and pro-inflammatory cytokine (IL-$1{\beta}$). This is the first report on DMfree inhibition of IL-6 and IL-$1{\beta}$ expression in M. leprae infected MSC. Further experiments that detect protein levels of IL-$1{\beta}$ and IL-6 may support the result of this gene array.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.4
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• pp.521-525
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• 2011

It is known that the low-intensity sound stimulation really affect to grow the cell. The cellular growth mechanism, however, does not been clearly identified even the effect on the low-intensity sound stimulation. The purpose of this study is to investigate the effect of low-intensity sound stimulation on the alveolar UC-MSC proliferation. Before the low-intensity sound stimulation is applied, the UC-MSC are cultured for 24 hours to facilitate their attachments. The cells are divided into two groups. And each was exposed to a medium with or without the low-intensity ultrasound stimulation at 71dB intensity level. The UC-MSC are again divided into three treatment groups of group 1, 2, and 3 and exposed to a frequency at 50Hz, 100Hz, and 1000Hz, respectively. In the results, it is investigated that the growth rates of UC-MSC for the stimulated groups were higher than those of control groups. In 1000Hz frequency, the number of UC-MSC cell is significantly higher than control groups (p>0.05). We would put the hypothesis that the cell growth could be enhanced by an appropriate low-intensity sound stimulation.

• Biomolecules & Therapeutics
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• v.26 no.5
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• pp.474-480
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• 2018

Most angiogenesis assays are performed using endothelial cells. However, blood vessels are composed of two cell types: endothelial cells and pericytes. Thus, co-culture of two vascular cells should be employed to evaluate angiogenic properties. Here, we developed an in vitro 3-dimensional angiogenesis assay system using spheroids formed by two human vascular precursors: endothelial colony forming cells (ECFCs) and mesenchymal stem cells (MSCs). ECFCs, MSCs, or ECFCs+MSCs were cultured to form spheroids. Sprout formation from each spheroid was observed for 24 h by real-time cell recorder. Sprout number and length were higher in ECFC+MSC spheroids than ECFC-only spheroids. No sprouts were observed in MSC-only spheroids. Sprout formation by ECFC spheroids was increased by treatment with vascular endothelial growth factor (VEGF) or combination of VEGF and fibroblast growth factor-2 (FGF-2). Interestingly, there was no further increase in sprout formation by ECFC+MSC spheroids in response to VEGF or VEGF+FGF-2, suggesting that MSCs stimulate sprout formation by ECFCs. Immuno-fluorescent labeling technique revealed that MSCs surrounded ECFC-mediated sprout structures. We tested vatalanib, VEGF inhibitor, using ECFC and ECFC+MSC spheroids. Vatalanib significantly inhibited sprout formation in both spheroids. Of note, the $IC_{50}$ of vatalanib in ECFC+MSC spheroids at 24 h was $4.0{\pm}0.40{\mu}M$, which are more correlated with the data of previous animal studies when compared with ECFC spheroids ($0.2{\pm}0.03{\mu}M$). These results suggest that ECFC+MSC spheroids generate physiologically relevant sprout structures composed of two types of vascular cells, and will be an effective pre-clinical in vitro assay model to evaluate pro- or anti-angiogenic property.

• Preventive Nutrition and Food Science
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• v.15 no.4
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• pp.267-274
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• 2010

We assessed the effect of Se-methylselenocysteine (MSC) treatment, at a dose of 0.75 mg/rat/day for 1 or 2 weeks, on the activities of antioxidant systems in Sprague-Dawley rat tissues. Significant changes in glutathione and antioxidant enzyme activities, with different patterns among tissues, were evidenced. Glutathione content and its reduction state in the liver, lung, and kidney were elevated upon MSC treatment, whereas they were significantly lowered in the spleen. Among the tissues exhibiting glutathione increase, there were different enzymatic responses: $\gamma$-glutamylcysteine ligase activity, the rate-limiting enzyme in the glutathione synthesis pathway, was increased in the liver, whereas the activities of the enzymes associated with glutathione recycling, namely, glutathione peroxidase, glutathione reductase, and glucose 6-phosphate dehydrogenase, were significantly increased in the lung and the kidney. The superoxide dismutase activity was decreased in all tissues upon MSC treatment, whereas catalase activity was increased in all tissues but the liver. Lipid peroxidation level was transiently increased at 1 week in the lung and the kidney, whereas it was persistently increased in the spleen. The increase was not evident in the liver. The results indicate that the MSC treatment results in an increase in the antioxidant capacity of the liver, lung, and kidney principally via an increase in glutathione content and reduction, which appeared to be a result of increased synthesis or recycling of glutathione via tissue-dependent adaptive response to oxidative stress triggered by MSC. The spleen appeared to be very sensitive to oxidative stress, and therefore, the adaptive response could not provide protection against oxidative damage.

• Korean Journal of Remote Sensing
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• v.23 no.5
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• pp.431-437
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• 2007

Multi-Spectral Camera(MSC) on the KOMPSAT-2 satellite was developed and launched as a main payload to provide 1m of GSD(Ground Sampling Distance) for one(1) channel panchromatic imaging and 4m of GSD for four(4) channel multi-spectral imaging at 685km altitude covering l5km of swath width. Since the compression on MSC image chain was required to overcome the mismatch between input data rate and output date rate JPEG-like method was selected and analyzed to check the influence on the performance. In normal operation the MSC data is being acquired and transmitted with lossy compression ratio to cover whole image channel and full swath width in real-time. In the other hand the MSC performance have carefully been handled to avoid or minimize any degradation so that it was analyzed and restored in KGS(KOMPSAT Ground Station) during LEOP(Launch and Early Operation Phase). While KOMPSAT-2 had been developed, new compression method based upon wavelet for space application was introduced and available for next satellite. The study on improvement of image chain including new compression method is asked for next KOMPSAT which requires better GSD and larger swath width In this paper, satellite image chain which consists of on-board image chain and on-ground image chain including general MSC description is briefly described. The performance influences on the image chain between two on-board compression methods which are or will be used for KOMPSAT are analyzed. The differences on performance between two methods are compared and the better solution for the performance improvement of image chain on KOMPSAT is suggested.

• Korean Journal of Remote Sensing
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• v.21 no.3
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• pp.173-188
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• 2005

The present study aims to derive and compare narrow and broad bandwidths of ocean color sensor’s algorithms for the study of monitoring highly dynamic coastal oceanic environmental parameters using high-resolution imagery acquired from Multi-spectral Camera (MSC) on KOMPSAT-2. These algorithms are derived based on a large data set of remote sensing reflectances ($R_{rs}$) generated by using numerical model that relates $b_b/(a + b_b)$ to $R_{rs}$ as functions of inherent optical properties, such as absorption and backscattering coefficients of six water components including water, phytoplankton (chl), dissolved organic matter (DOM), suspended sediment (SS) concentration, heterotropic organism (he) and an unknown component, possibly represented by bubbles or other particulates unrelated to the first five components. The modeled $R_{rs}$ spectra appear to be consistent with in-situ spectra collected from Korean waters. As Kompsat-2 MSC has similar spectral characteristics with Landsat-5 Thematic Mapper (TM), the model generated $R_{rs}$ values at 2 ㎚ interval are converted to the equivalent remote sensing reflectances at MSC and TM bands. The empirical relationships between the spectral ratios of modeled $R_{rs}$ and chlorophyll concentrations are established in order to derive algorithms for both TM and MSC. Similarly, algorithms are obtained by relating a single band reflectance (band 2) to the suspended sediment concentrations. These algorithms derived by taking into account the narrow and broad spectral bandwidths are compared and assessed. Findings suggest that there was less difference between the broad and narrow band relationships, and the determination coefficient $(r^2)$ for log-transformed data [ N = 500] was interestingly found to be $(r^2)$ = 0.90 for both TM and MSC. Similarly, the determination coefficient for log-transformed data [ N = 500] was 0.93 and 0.92 for TM and MSC respectively. The algorithms presented here are expected to make significant contribution to the enhanced understanding of coastal oceanic environmental parameters using Multi-spectral Camera.

• The Journal of Advanced Prosthodontics
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• v.13 no.3
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• pp.180-190
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• 2021

Purpose. This study aimed to assess the influence of various micromechanical surface conditioning (MSC) strategies with or without coupling agent (silane) application on the micro-shear bond strength (µSBS) of resin- matrix ceramics (RMCs). Materials and Methods. GC Cerasmart (GC), Lava Ultimate (LU), Vita Enamic (VE), Voco Grandio (VG), and Brilliant Crios (BC) were cut into 1.0-mm-thick slices (n = 32 per RMC) and separated into four groups according to the MSC strategy applied: control-no conditioning (C), air-borne particle abrasion with aluminum oxide particles (APA), 2W- and 3W-Er,Cr:YSGG group coding is missing. The specimens in each group were further separated into silane-applied and silane-free subgroups. Each specimen received two resin cement microtubules (n = 8 per subgroup). A shear force was applied to the adhesive interface through a universal test machine and µSBS values were measured. Data were statistically analyzed by using 3-way ANOVA and Tukey HSD test. Failure patterns were scrutinized under stereomicroscope. Results. RMC material type, MSC strategy, and silanization influenced the µSBS values (P<.05). In comparison to the control group, µSBS values increased after all other MSC strategies (P<.05) while the differences among these strategies were insignificant (P>.05). For control and APA, there were insignificant differences between RMCs (P>.05). The silanization decreased µSBS values of RMCs except for VE. Considerable declines were observed in GC and BC (P<.05). Conclusion. MSC strategies can enhance bond strength values at the RMC - cement interface. However, the choice of MSC strategy is dependent on RMC material type and each RMC can require a dedicated way of conditioning.