• Journal of Radiation Protection and Research
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• v.16 no.2
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• pp.27-39
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• 1991

The diffusion of Sr-85, Cs-137, Co-60 and Am-241 in compacted domestic bentonite was studied, using a diffusion cell unit in which diffusion took place axially from the center of cylindrical bentonite sample body. The effects of compaction density and heat-treated bentonite on diffusion were analysed. And the diffusion mechanism of radionuclide was also analysed by evaluating the measured diffusivity of anion Cl-36. The apparent diffusivities obtained for Sr-85, Cs-137, Co-60 and Am-241 were $l.07{\times}10^{-11},\;6.705{\times}10^{-13},\;l.226{\times}10^{-13}\;and\; l.310{\times}10^{-14}m^2/sec$, respectively. When the as-pressed density of bentonite increased from $1.8\;to\;2.0g/cm^3$, the apparent diffusivity of Cs-137 decreased by quarter. In the case of bentonite heat-treated to $150^{\circ}C$, no significant change in diffusivity was observed, which showed the possibility that the domestic bentonite could be used as a chemical barrier to retard the radionuclide migration at below $150^{\circ}C$. From the calculated pore and surface diffusivity, the surface diffusion due to the concentration gradient of radionuclide sorbed on the solid phase was found to dominate greatly in total transport process.

• Journal of Radiation Protection and Research
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• v.42 no.4
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• pp.189-196
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• 2017

Background: The effects of radiation on tissues vary depending on the radiation type. In this study, a minipig model was used to compare the effects of ${\beta}$-rays from $^{166}Ho$ and ${\gamma}$-rays from $^{60}Co$ on the skin. Materials and Methods: In this study, the detrimental effects of ${\beta}$- and ${\gamma}$-irradiation on the skin were assessed in minipigs. The histopathological changes in the skin from 1 to 12 weeks after exposure to 50 Gy of either ${\beta}$- (using $^{166}Ho$ patches) or ${\gamma}$- (using $^{60}Co$) irradiation were assessed. Results and Discussion: The skin irradiated by ${\beta}$-rays was shown to exhibit more severe skin injury than that irradiated by ${\gamma}$-rays at 1-3 weeks post-exposure; however, while the skin lesions caused by ${\beta}$-rays recovered after 8 weeks, the ${\gamma}$-irradiated skin lesions were not repaired after this time. The observed histopathological changes corresponded with gross appearance scores. Seven days post-irradiation, apoptotic cells in the basal layer were detected more frequently in ${\beta}$-irradiated skin than in ${\gamma}$-irradiated skin. The basal cell density and skin thickness gradually decreased until 4 weeks after ${\gamma}$- and ${\beta}$- irradiation. In ${\beta}$-irradiated skin lesions, and the density and thickness increased sharply back to control levels by 6-9 weeks. However, this was not the case in ${\gamma}$-irradiated skin lesions. In ${\gamma}$-irradiated skin, cyclooxygenase-2 (COX-2) was shown to be expressed in the epidermis, endothelial cells of vessels, and fibroblasts, while ${\beta}$-irradiated lesions exhibited COX-2 expression that was mostly limited to the epidermis. Conclusion: In this study, ${\beta}$-rays were shown to induce more severe skin injury than ${\gamma}$-rays; however, the ${\beta}$-rays-induced injury was largely repaired over time, while the ${\gamma}$-rays-induced injury was not repaired and instead progressed to necrosis. These findings reveal the differential effects of ${\gamma}$- and ${\beta}$-irradiation on skin and demonstrate the use of minipigs as a beneficial experimental model for studying irradiation-induced skin damage.

• Korean Journal of Acupuncture
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• v.24 no.3
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• pp.205-221
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• 2007

Objectives : Aims of this study is to investigate the effects of $LU8{\cdot}KI7$ in rat induced by experimental focal ischemia. Materials and methods : The focal ischemia was induced by intraluminal filament insertion into middle cerebral artery. The groups divided into 6groups, control; no therapy group after ischemia-induced, AT1; acupuncture therapy group at $LU8{\cdot}KI7$ after ischemia-induced, AT2; acupuncture therapy at $LU8{\cdot}KI7$ bilaterally and the needle was twirled and rotated forward with the thumb of the right hand 9times, AT3; acupuncture therapy at $LU8{\cdot}KI7$ bilaterally and the needle was twirled and rotated forward with the forefinger of the right hand 9times, AT4; acupuncture therapy at$LU8{\cdot}KI7$ bilaterally and the needle was inserted to the direction following the flowing route of the meridian(digital direction), AT5; acupuncture therapy at $LU8{\cdot}KI7$ bilaterally, the needle was inserted to the direction following the flowing route of the meridian(digital direction) and the needle was twirled and rotated forward with the thumb of the right hand 9times. Acupuncture therapy was carried out 7times during 2weeks after focal ischemia-induced. The anti-apoptotic and neuroprotective effects of acupuncture are observed by Bax, Bcl-2, mGluR5, cytochrome c, Cresyl violet and ChAT-stain. Results : The intensity of Bax was decreased in AC1, AC4, AC5 group, was increased in AC2, AC3 group. The intensity of Bcl-2 was increased in AC2, AC3, AC4, AC5 group. The intensity of mGluR5 was decreased in AC1 group, was increased in AC4, AC5 group. The intensity of Cytochrome c was increased in ACI, AC2 group, was decreased in AC4, AC5 group. The density of neurons stained by Cresyl violet was increased in all group without control group. The density of ChAT was increased in AC2, ACS group. Conclusions : Our study suggests that AC5 group show anti-apoptotic and neuroprotective effects on cholinergic neuron in focal cerebral ischemia of the stroke in rats.

• Journal of Marine Bioscience and Biotechnology
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• v.8 no.1
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• pp.18-23
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• 2016

It is important to design photobioreactor by cheap material for economical microalgal biomass production. In this study, two types of marine photobioreactors (MPBR), made by either polyvinyl chloride (MPBR-PVC) or high density poly ethylene (MPBR-HDPE), are used and performance of these were compared. Tetraselmis sp. KCTC 12236BP is a green marine alga that isolated from Ganghwa Island, Korea, and the strain was used for marine cultivations using MPBR-PVC and MPBR-HDPE. The cultivations were performed three times in the spring season of 2012 using MPBR-PVC and of 2013 using MPBR-HDPE in the coastal area of Young Heung Island. As the results, MPBR-PVC shows higher biomass productivities than MPBR-HDPE, due to its high light transmittance. In the cultivations using MPBR-PVC, the average sea water temperature was $11.5^{\circ}C$ during the first experiment and $16.5^{\circ}C$ during the second and third experiments. Average light intensities during three times for experiments were 407.5, 268.1 and $273.0{\mu}{\cdot}E{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. The maximum fresh cell weight and average biomass productivity were $1.2g{\cdot}L^{-1}$ and $0.12g{\cdot}L^{-1}{\cdot}day^{-1}$. These results showed that Tetraselmis sp. KCTC12236BP were adapted well with the environmental conditions from ocean, and grow in the MPBR-PVC and MPBR-HDPE.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.649-663
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• 1998

The clarify the ecological properties, and to predict change of understory vegetation of mt. Nam Park, population dynamics and interspecific competition of D. smilacinum and D. viridescens, which grow in understory of deciduous broad-leaved forest and pseudo-annuals, were studied from May 20 to May 30 1998. The depth of litter layer, soil moisture content, soil organic matter and soil texture were surveyed in 18 populations (15 D. smilacinum populations and 3 D. viridescens populations). Mean litter layer of d. smilacimum population was thinner than that of D. viridescens populations). Mean litter layer of D. smilacnum population was thinner than that of D. viridescens population. The contents of soil moisture and organic matter of D. smilacinum population were lower than that of D. viridescens population. The D. smilacinum growed in broad range of soil texture but D. viridescens in loamy soil. Because D. smilacinum could tolerate more broad range of soil moisture and soil texture than D. viridescens, the former covered the herb layer in earlier stage and the latter introduced in later stage when rhizome could grow easily. The numbers of individual in two marginal parts were smaller than that in center in same D. smilacinum patch. And the total numbers of individuals grown in (10 ${\times}$ 10)cm were from 0 to 12. The rhizome (subterranean runner) weight, rhizome length, root weight, shoot weight, lea weight and leaf number per subquadrat (cell) increased along the number of individual, that is, increased from marginal part to center. But rhizome weight and rhizome length per individual were vice versa. Therefore, the individuals in marginal part reproduced longer and stronger asexual propagules than that in center. The distribution pattern of D. smilacinum was contageous and that of D. viridescens was random or regular. Therefore, population growth of former was independent on density and that of latter was dependent on density. The distributions of size-class showed normal curves in two population, but the curves based on data of total dry weight showed positive skewness and those of leaf number showed negative skewness The correlation coefficient (CC) values between the properties of each organ were high in two population and significant at 0.1% level. The CC values of D. viridescens were higher of the two. Therefore, the former allocated the energy to each organ stable. The rhizome depth of d. viridescens was 2 times deeper than that of D. smilacinum. And rhizome length and weight of D. viridescens were longer (2 times) or heavier (4 times) than those of D. smilacinum. The patch size of D. viridescens increased 60 cm per year and that of D. smilacinum 30 cm. On this results, the intrinsic increase velocity of d. viridescens patch was 2 times faster than that of d. smilacinum, therefore, on the competition, the former had an advantage over D. smilacinum. The reason why d. viridescens defeated D. smilacinum resulted from that the leaf area of former was 4 times broader than that of latter. in Mt. Nam Park, it was thought that two disporum Population would change with the 3 thpes of environmental change as followings. First, no human impact and increase of soil moisture content resulted in increase of D. viridescens population. Second, mild human impact and similar condition of soil moisture content resulted in slow increase or no changes of D. smilacinum and d. viridescens population. Third, severe human impact and dry condition resulted in decrease or vanishment of two disporum populations.

• Applied Microscopy
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• v.28 no.2
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• pp.215-224
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• 1998

To investigate ultrastructural changes on the adrenal glands of the developmental rats, tissues were collected at 20 days of gestation, at birth, 7 days, 15 days and 30 days after birth and studied by electron microscope. In the medulla of adrenal gland of the rat, two types of granules were observed at ultrastructural level. The one were adrenaline $(123\sim200nm)$ and the others were noradrenaline ($177\sim279nm$ of long axis, $124\sim194$ of short axis). Adrenaline granules were characterized by presence of round or spherical with low or moderate electron density. The granules showed a wide lucent or clean halo between the contents and the limiting membrane. On the other hand noradrenaline granules were characterized by the presence of irregular shape with high electron density. This granules showed a wide lucent between the contents and limiting membrane. These two types of granules were co-existed in one cell in the late gestation and at birth, but after that two types of cells were clearly observed. The different sizes and numbers of granules were observed with ages.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.183-187
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• 1998

In order to characterize the microbial distribution at sediments of Lake Daechung, soil samples were collected at two depths of 0.5~2 cm and 19~21 cm of Chudong(static) and Hoenam(streaming) site on May 18th(before rainy season) and on August 24th in 1998(after rainy season), and then the density(CFU/g soil) of microorganisms including bacteria, actinomycetes, and fungi was investigated by the viable cell counting method. Microbial density at streaming site was on the whole 3.9-fold higher than that at static site. Bacterial densities examined before and after rainy season was revealed to be similar, whereas actinomycetes and fungi exhibited higher distribution after and before rainy season, respectively. The microbial distribution was not generally reduced with the increase of depth and was rather higher at some deep sites. On comparing with the microbial densities of grass land around the lake, bacteria, actinomycetes, and fungi at lake sediments on the average showed the distribution of 52.9%, 35%, and 7%, respectively. However, their distribution except for fungi which exhibited 71.2% was mostly found to be somewhat higher than at the shore of lake.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1337-1345
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• 2006

Hypercholesterolemia is a pivotal pathogenic factor for the development and maintenance of atherosclerosis. The present study was designed to evaluate whether the methanol extract of Sorbus commixta cortex (MSC) restores vascular dysfunction in association with the aortic expressions of proinflarnmatory and adhesion molecules in high cholesterol (HC) diet-rats. Chronic treatment with low (100 mg/kg/day) or high doses (200 mg/kg/day) of MSC lowered the increase in plasma levels of triglyceride (TG) and low-density lipoprotein (LDL) cholesterol induced by a cholesterol-enriched diet without affecting on the plasma level of high density lipoprotein (HDL)-cholesterol. Vascular tone attenuated in the HC-diet rats was restored by administration with MSC. Treatment with MSC also suppressed the HC-induced increase in the monocyte chemoattractant protein-1 (MCP-1) and nuclear factor-$_K$B (NF-$_K$B) p65 expressions as well as expressions levels of adhesion molecules including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (ICAM-1), and E-selectin in aorta. The present study also showed that MSC inhibited the HC-mediated induction of ET-1 and ACE expression. In histopathological examination, aortic segments in the HC-diet rat revealed thickening intima and media, which were blocked by administration with MSC. Taken together, MSC could suppress the development of atherosclerosis in the HC-diet rat model through the inhibition of the aortic expression levels of pro-inflammatory and adhesion molecules.

• Journal of the Korean Electrochemical Society
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• v.22 no.4
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• pp.139-147
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• 2019

Lithium-ion battery (LiB) with high energy density and efficiency has been utilized for the electric vehicle (EV) and energy storage system (ESS) as well as portable devices. However, as explosion accidents have frequently happened till lately, all-solid-state lithium secondary battery (ALSB) began to get in a spotlight because it can secure a very high safety and energy density by substituting flammable organic liquid electrolyte to nonflammable inorganic solid electrolyte. In spite of ALSB's certain merits, it has shown much poorer performance of cells than one of LiB due to some challenges, which have been small or never dealt with in the LiB system. Hence, although plenty of studies made progress to solve them, an approach about design of all-solid-state electrode (ASSE) has been limited on account of difficulty of ALSB's experiments. That is why the virtual 3D structure of an all-solid-state electrode has to be built and used for the prediction of cell performance. In this study, we elucidate how to form the 3D ASSE structure and what to be needed for the simulation of characteristics on ALSB. Furthermore, the ultimate orientation of 3D modeling and simulation for the study of ALSB are briefly suggested.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.696-702
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• 2018

Recently, the current thermal battery technology needs new materials for electrodes in the power and energy density to meet various space and defense requirements. In this paper, to replace the pellet type Li(Si) anode having limitations of the formability and capacity, electrochemical properties of the lithium anode with high density for thermal batteries were investigated. The lithium anode (Li 17, 15, 13 wt%) was fabricated by mixing the molten lithium and iron powder used as a binder to hold the molten lithium at $500^{\circ}C$. The single cell with 13 wt% lithium showed a stable performance. The 2.06 V (OCV) of the lithium anode was significantly improved compared to 1.93 V (OCV) of the Li(Si) anode. Specific capacities during the first phase of the lithium anode and Li(Si) were 1,632 and $1,181As{\cdot}g^{-1}$, respectively. As a result of the thermal battery performance test at both room and high temperatures, the voltage and operating time of lithium anode thermal batteries were superior to those of using Li(Si) anode thermal batteries. The power and energy densities of Li anode thermal batteries were also remarkably improved.