• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.620-626
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• 1988

GaAs solar cells may be the most attractive and efficient power source of a satellite. GaAs is more radiation tolerant and less temperature sensitive than widely used silicon. $Al_{x}$ Ga$_{1-x}$ As/GaAs solar cells have been designed and fabricated by Liquid Phase Epitaxial method. GaAs solar cells, of which structure is about 0.2 .mu.m p$^{+}$ - window layer, 0.6-1.O .mu.m Ge-doped p-layer. 3.mu.m n-GaAs layer and n$^{+}$ - buffer layer, have been characterized as a function of operating temperature from 25 .deg.C to 130 .deg.C. Open circuit voltage decreases linearly with increasing temperature by 1.4-1.51 mV/ .deg.C while degradation of silicon solar cells is about 2.2-2.5 mV/ .deg.C, short circuit current does not increase much with increasing temperature. Relative efficiency decreases with increasing of temperature by about 0.21-0.29 %/ .deg.C. Efficiency degradation of silicon solar cells with temperature is known to be about 0.5%/ .deg.C and our results show GaAs solar cells may be an excellent candidate for concentrated solar cells.ells.

• Applied Microscopy
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• v.40 no.1
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• pp.15-19
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• 2010

The present study was designed to demonstrate ionic zinc in the rat DRG by means of zinc selenium autometallography($ZnSe^{AMG}$). Ganglion cells varied in size from 15 to 100 ${\mu}m$. The smaller neurons were strongly stained with AMG, whereas the larger cells were weakly stained. Each large ganglion cell was surrounded by perineuronal satellite cells, showing apparent AMG staining. We demonstrated for the first time the existence of zinc-containing satellite cells in the rodent DRG. Using electron microscopy, fine AMG grains were observed scattered in the somata of the DRG neurons, especially small cells. However, much lower concentrations of the AMG grains occupied in the large cells, and these were mostly localized in lysosome-like organelles. These results indicate that zinc may be involved in sensory transmission in the DRG level.

• Atmosphere
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• v.21 no.3
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• pp.273-284
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• 2011

This study investigates the characteristics of satellite brightness temperature (TB) and rainfall intensity over the life cycle of convective cells. The convective cells in the three event cases are detected and tracked from the growth stage to the dissipation stage using the half-hourly infrared (IR) images. For each IR images the values of minimum, mean, and variance for the convective cell's TBs and the sizes of convective cells are calculated and also the relationship between TB and rainfall intensity are investigated, which is obtained using the pixel values of satellite TB and the ground rainfall intensity measured by AWS (Automatic Weather Station). At the growth stage of the convective cells, the TB's variance and cloud size consistently increased, whereas TB's minimum and mean consistently decreased. At this stage the empirical relationships between TB and rainfall intensity are statistically significant and their slopes (intercepts) in absolute values are relatively large (small) compared to those at the dissipation stage. At the dissipation stage of the convective cells, the variability of TB distributions shows the opposite trend. The statistical significance of the empirical relationships are relatively weak, but their slopes (intercepts) vary over life cycle. These results indicate that satellite IR images can provide valuable information in identifying the convective cell's maturity stage and in the growth stage, they may be used in providing considerably accurate rainfall estimates.

• Applied Microscopy
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• v.25 no.1
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• pp.30-47
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• 1995

The ultrastructural changes of adrenal chromaffin cells and ganglion cells in the adrenal gland of vacor-induced diabetic Mongolian gerbils were studied by electron microscopy. After one month of vacor-induced diabetes, some chromaffin cells were filled with dense bodies and large cytosomes with formy contents. Most of degenerating axon terminals were observed on chromaffin cells. A few macrophages were found among chromaffin cells at one month after induction. Several of these macrophages were filled with numerous phagosomes. After one month of vacor-induced diabetes, the ganglion cells showed increase in numbers of dense bodies and degenerating dendrites compared with the normal ganglion cells. Both electron dense and lucent types of degenerating axon terminals were found in interstitial space of the ganglion cells. Degenerating unmyelinated and myelinted axons contained dense and lamellar bodies. The satellite cells and macrophages with engulfed degenerated axon terminals were observed. After three months of vacor-induced diabetes, the unmyelinated and myelinated axons showed degenerative changes, whereas no structural changes could be demonstrated in adrenal ganglion and chromaffin cells. The satellite cells and macrophages containing partially digested debris were still commonly observed in the interstitial space of adrenal medulla. These results suggest that the degenerative changes occur in the adrenal ganglion cells as well as adrenal chromaffin cells of vacor-induced diabetic Mongolian gerbils.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.715-723
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• 2018

The present study was done to investigate the effect of co-culturing muscle satellite cells (MSCs) and intramuscular preadipocytes (IPs) on the differentiation of adipocytes and muscle cells isolated from Korean native cattle. MSCs and IPs were single-cultured in 10% fetal bovine serum/Dulbecco's modified Eagles medium (FBS/DMEM) for 48 h followed by culturing in 5% FBS/DMEM as the growth media. Then, the growth media was replaced by differentiation media composed of 2% FBS/DMEM without any additives for the single- or co-culture of muscle cells and intramuscular adipocytes to induce the differentiation of both cell types. Cell differentiation was measured by morphological investigation and cytosolic enzyme analysis of glycerol-3-phosphate dehydrogenase (GPDH) for the adipocytes and creatine kinase (CK) for the muscle cells. In the morphological test, the presence of muscle cells did not stimulate adipocyte differentiation showing more differentiation of the adipocytes in the single-culture compared to the co-culture condition. However, the differentiation of muscle cells was promoted by adipocytes in the co-culture. The results of the enzymatic analysis were highly associated with the morphological results with a statistically higher GPDH activity (p < 0.05) appearing in the single-culture than in the co-culture, whereas the opposite was true for the CK activity of the muscle cells (p < 0.05). By manipulating in vivo the milieu using a co-culture, we could detect the difference in the rate of cell differentiation and suggest that a co-culture system is a more reliable and precise technique compared to a single-culture. Further studies on various co-culture trials including supplementation of differentiating substances, gene expression analysis, etc. should be done to obtain practical and fundamental data.

• Food Science of Animal Resources
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• v.43 no.4
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• pp.563-579
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• 2023

Myogenesis and adipogenesis are the important processes determining the muscle growth and fat accumulation livestock, which ultimately affecting their meat quality. Hanwoo is a popular breed and its meat has been exported to other countries. The objective of this study was to compare the myogenesis and adipogenesis properties in satellite cells, and meat quality between Hanwoo and Vietnamese yellow cattle (VYC). Same 28-months old Hanwoo (body weight: 728±45 kg) and VYC (body weight: 285±36 kg) steers (n=10 per breed) were used. Immediately after slaughter, tissue samples were collected from longissimus lumborum (LL) muscles for satellite cells isolation and assays. After 24 h post-mortem, LL muscles from left carcass sides were collected for meat quality analysis. Under the same in vitro culture condition, the proliferation rate was higher in Hanwoo compared to VYC (p<0.05). Fusion index was almost 3 times greater in Hanwoo (42.17%), compared with VYC (14.93%; p<0.05). The expressions of myogenesis (myogenic factor 5, myogenic differentiation 1, myogenin, and myogenic factor 6)- and adipogenesis (peroxisome proliferator-activated receptor gamma)-regulating genes, and triglyceride content were higher in Hanwoo, compared with VYC (p<0.05). Hanwoo beef had a higher intramuscular fat and total monounsaturated fatty acids contents than VYC beef (p<0.05). Whilst, VYC meat had a higher CIE a* and total polyunsaturated fatty acids content (p<0.05). Overall, there was a significant difference in the in vitro culture characteristics and genes expression of satellite cells, and meat quality between the Hanwoo and VYC.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.1-5
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• 2008

This paper analyzes on the radiation effect of silicon solar cells in a low Earth orbit satellite by using high energy electron beams. Generally, the satellite circling round in a low orbit go through Van Allen belt, in which electronic components are easily damaged and shortened by charged particles moving in a cycle between the South Pole and the North Pole. For example, Single Event Upset (SEU) by radiation could cause electronic devices on satellite to malfunction. From the ground experiment in which we used the high energy electron beam facility at Knrea Atomic Energy Research Institute (KAERI), we tried to explain sun sensor degradations on orbit could he caused by high energy electrons. While we focused on the solar cells used for light detectors, We convince our research also contributes to understand the radiation effect of solar cells generating electric powers on satellites.

• Applied Microscopy
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• v.23 no.2
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• pp.107-123
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• 1993

The ultrastructural changes of the cardiac ganglion and granule-containing cells in the heart of vacor-induced diabetic Mongolian gerbils were studied by electron microscopy. After one month of vacor-induced diabetes the ganglion cells showed increase in numbers of dense bodies and mitochondria compared with the normal cardiac ganglion. Most of the satellite cells were filled with numerous phagosomes containing digested debris. Both electron-dense and lucent types of degenerating axon terminals were observed. The former was characterized by clusters of agranular vesicles and numerous mitochondria. The electron lucent type of degenerating axon terminal contained a few agranular vesicles and swollen mitochondria. Degenerating unmyelinated and myelinated axons contained large numbers of dense bodies, lamellar bodies, and mitochondria. Numerous macrophages containing phagosomes were reveled in the interstitial spaces. Some of the granule-containing cells in the heart showed a variety of degenerative changes and a decreased number of dense-cored vesicles. After three months of vacor-induced diabetes the unmyelinated and myelinated axons showed degenerative changes, whereas no structure changes could be demonstrated in intraatrial ganglion and granule containing cells. The satellite cells containing engulfed debris were observed in the cardiac ganglion cells. These results suggest that the degenerative changes occur in the cardiac ganglion cells of vacor-induced diabetic Mongolian gerbils as well as atrial granule-containing cells.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.5
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• pp.649-658
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• 2010

Myogenic satellite cells (MSCs) are adult stem cells that activate and differentiate into myotubes. These stem cells are multipotent as they transdifferentiate into adipocyte-like cells, nerve cells and osteocytes. The effects of steroid hormones ($E_2$ and testosterone) were studied as a further step toward understanding the mechanism of MSCs proliferation and differentiation. In this study, MSCs were grown continuously for 87 days, implying that there may be a group of MSCs that continue to proliferate rather than undergoing differentiation. Isolated MSCs were cultured in Dulbecco's Modified Eagle's Medium supplemented with adult male, female or castrated bovine serum to observe the effect of steroid hormones on MSC proliferation. Cell proliferation was the highest in cultures supplemented with male serum followed by female and castrated serum. The positive effect of male hormone on MSC proliferation was confirmed by the observation of testosterone-mediated increased proliferation of cells cultured in medium supplemented with castrated serum. Furthermore, steroid hormone treatment of MSCs increased lipid accumulation in myotubes. Oil-Red-O staining showed that 17${\beta}$-estradiol ($E_2$) treatment avidly increased lipid accumulation, followed by $E_2$+testosterone and testosterone alone. To our knowledge, this is the first report of lipid accumulation in myotubes due to steroids in the absence of an adipogenic environment, and the effect of steroid hormones on cell proliferation using different types of adult bovine serum, a natural hormonal system. In conclusion, we found that sex steroids affect MSCs proliferation and differentiation, and lipid accumulation in myotubes.

• Reproductive and Developmental Biology
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• v.37 no.4
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• pp.225-232
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• 2013

Satellite cells were derived from muscular tissue in postnatal pig. Satellite cell is an important to growth and development in animal tissues or organs. However, the progress underlying induced differentiation is not clear. The aim of this study was to evaluate the morphologic and the transcriptome changes in porcine satellite cell (PSC) treated with insulin, rosiglitazone, or dexamethasone respectively. PSC was obtained from postnatal muscle tissue. In study 1, for study the effect of insulin and FBS on the differentiated satellite cells, cells were cultured at absence or presence of insulin treated with FBS. Total RNA was extracted for determining the expression levels of myogenic PAX3, PAX7, Myf5, MyoD, and myogenin genes by real-time PCR. Myogenic genes decreased expression levels of mRNA in treated with insulin. In study 2, in order to clarify the relationship between rosiglitazone and lipid in differentiated satellite cells, we further examined the effect of FBS on lipid accumulation in the presence or absence of the rosiglitazone and lipid. Significant differences were observed between rosiglitazone and lipid by FBS. The mRNA of FABP4 and $PPAR{\gamma}$ increased in rosiglitazone treatment. In study 3, we examined the effect of dexamethasone on osteogenic differentiation in PSC. The mRNA was increased osteoblasotgenic ALP and ON genes treated with dexamethasone in 2% FBS. Dexamethasone induces osteoblastogenesis in differentiated PSC. Taken together, in differentiated PSCs, FABP4 and $PPAR{\gamma}$ increased to rosiglitazone. Whereas, no differences to FBS and lipid. These results were not comparable with previous reports. Our results suggest that adipogenic, myogenic, and osteoblastogenic could be isolated from porcine skeletal muscle, and identify culture conditions which optimize proliferation and differentiation formation of PSC.