• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.500-509
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• 2014

To prevent freezing of the road by fallen snow, Calcium chloride($CaCl_2$) as a deicer is used to very often and it can be harmful to roadside trees. This study was conducted to investigate the effects of Calcium chloride($CaCl_2$) as a deicer on growth and physiological traits of Acer triflorum according to different concentration of $CaCl_2$. We measured growth, chlorophyll contents, gas exchangement characteristics, chlorophyll fluorescence and mineral nutrition concentration in plant and soil. The experimental group was composed of four treatments including 0mM(control), 9mM(0.5 %), 18mM(1.0 %), 54mM(3.0 %). Before germinating new shoot, the dissolution of $CaCl_2$ was irrigated twice interval of a week. At 30 days after treatment, all treatments decreased total cholorophyll content, photosynthetic rate, transpiration rate, stomatal conductance and photochemical efficiency($F_v/F_m$) with increasing concentration of $CaCl_2$ and especially, they significantly reduced in 3.0 % treatment. In contrast, chlorophyll a/b ratio increased with an increase of $CaCl_2$ concentration and water use efficiency increased in 1.0 % and 3.0 % treatments. At 50 days after treatment, all treatments were decreased in chl a, chl b, total chlorophyll content, carotenoid content, photosynthetic capacity, photochemical efficiency($F_v/F_m$) and quantum yield of photosystem II(${\Phi}_{PSII}$) compared with control and 3.0 % treatments were withered. $Ca^{2+}$ and $Cl^-$ were accumulated in leaves and soil, which inhibited water absorption and electron transport and it caused the reduction of height growth rate more than 50 %. Although there was a little difference according to time and $CaCl_2$ concentration, all treatments decreased in growth rate and physiological activity slowed down. As time passed, these results got worse. Therefore we need to take a measure earlier in order to minimize damage of trees.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.62-73
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• 2000

Purpose: Esophageal cancer patients have a difficulty in the intake of meals through the blocked esophageal lumen, which is caused by an ingrowth of cancer cells and largely influences on the prognosis. It is reported that esophageal cancer has a very low survival rate due to the lack of nourishment and immunity as the result of this. In this study a new radioactive stent, which prevents tumor ingrowth and restenosis by additional radiation treatment, has been developed. Materials and Methods: Using ${\ulcorner}HANARO{\lrcorner}$ research reactor, the radioactive stent assembly ($^{166}Ho$-SA) was prepared by covering the metallic stent with a radioactive sleeve by means of a post-irradiation and pre-irradiation methods. Results: Scanning electron microscopy and autoradiography exhibited that the distribution of $^{165/166}Ho\;(NO_3)$ compounds in polyurethane matrix was homogeneous. A geometrical model of the esophagus considering its structural properties, was developed for the computer simulation of energy deposition to the esophageal wall. The dose distributions of $^{166}Ho$-stent were calculated by means of the EGS4 code system. The sources are considered to be distributed uniformly on the surface in the form of a cylinder with a diameter of 20 mm and length of 40 mm. As an animal experiment, when radioactive stent developed in this study was inserted into the esophagus of a Mongrel dog, tissue destruction and widening of the esophageal lumen were observed. Conclusion: We have developed a new radioactive stent comprising of a radioactive tubular sleeve covering the metallic stent, which emits homogeneous radiation. If it is inserted into the blocked or narrowed lumen, it can lead to local destruction of the tumor due to irradiation effect with dilatation resulting from self-expansion of the metallic property. Accordingly, it is expected that restenosis esophageal lumen by the continuous ingrowth and infiltration of cancer after insertion of our radioactive stent will be decreased remarkably.

• Applied Microscopy
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• v.39 no.2
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• pp.117-124
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• 2009

Clonorchis sinensis is the most important widely distributed parasite of the human bile duct in East Asia and the most prevalent parasitic helminth in Korea. The prevalence rate of human clonorchiasis has remained at about 2.9% in Korea. C. sinensis induces dilatation of the duct, hyperplasia of the mucosa, metaplasia or neoplasia of the mucosal epithelium, periductal inflammation and fibrosis, and thickening of the ductal wall. Fibroblast are the most common cells in connective tissue and are responsible for the synthesis of extracellular matrix components. The fibrosis associated with chronic inflammation and injury may also contribute to cholangiocarcinoma pathogenesis, particularly through an increase in extracellular matrix components, which participate in the regulation of bile duct differentiation during development. In this study, ultrastructural changes, the distribution of lectin receptors and actin protein in cultured SD rat bile duct fibroblast after infection of C. sinensis were observed. Experimental group had been divided into four groups: normal bile duct fibroblast cultured in basal media (G1); C. sinensis infected bile duct fibroblast cultured in basal media (G2); normal bile duct fibroblast cultured in basal media containing excretory-secretory product (ESP) (G1-1); C. sinensis infected bile duct fibroblast cultured in basal media containing ESP (G2-1). Overall, once a host is infected by C. sinensis, it affects the host to the extent that sialic acid of ductal fibroblast is increased. Number of cytoplasmic process of SD rat bile duct fibroblast was increased. Actin protein and sialic acid were located in cell surface. Fibroblast induced by C. sinensis was not recovered to normal fibroblast. The cytoplasm bulk and cytoplasmic process were increased whereas the growth rate of the fibroblast of infected SD rat was reduced rather than that of normal fibroblast. In result, it inhibits fibroblast proliferation and increases actin protein on fibroblast cytoplasm, and so causes fibroblast metamorphosis and cellular mutation.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.37-43
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• 1997

Tolerance mechanism to simazine (6-chloro-N,N'-diethyl-1,3,5-triazine-2,4-diamine) in Coix lacryma-jobi was investigated with respect to herbicide detoxification via glutathione conjugation. Simazine was initially absorbed by seedlings of C. lacryma-jobi and corn, but after 12 hours of treatment, no significant difference in simazine absorption was found in both species. Simazine absorbed was rapidly metabolized to glutathione-simazine conjugate. One to six hours after treatment, metabolism was approximately 2-fold faster in C. lacryma-jobi than in corn. Glutathione content was found 1.5- and 2.3-fold higher in coleoptile and root of C. lacryma-jobi, respectively, compared with corn. In both species, the highest concentration of glutathione was found in coleoptile tissue. Glutathione S-transferase that exhibits activity with 1-chloro-2,4-dinitrobenzene was not significantly different between two species. However, glutathione S-transferase activity with simazine was approximately 2-fold greater in C. lacryma-jobi than in corn. The glutathione S-transferase activity was 20 to 30% greater in shoot of either species than in root. Fast protein liquid chromatography-anion exchange column was used to separate glutathione S-transferase isozymes in coleoptiles of C. lacryma-jobi and corn. A peak of glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene and two peaks of glutathione S-transferase activity with simazine from C. lacryma-jobi were coeluted with those from corn, but showed greater activity than in the case of corn. Another glutathione S-transferase isozyme that exhibits activity with simazine was detected in the elution of C. lacryma-jobi extract, but not in corn. Electron transport in chloroplast thylakoids isolated from leaves of both species was equally sensitive to simazine applied at 1 to 100 nM. These results indicate that the simazine tolerance in C. lacryma-jobi is due to its capacity to detoxify the herbicide via glutathione conjugation, which is positively correlated with the level of glutathione content and glutathione S-transferase activity.

• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.55-75
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• 1974

Transovarial transmission of cytoplamic polyhedrosis virus in the silkworm was studied by observing the phenomena of induction, interference and virulence enhancement in the larvae from moths inoculated with hexagonal Polyhedra of cytoplasmic polythedrosis virus. The experimental results obtained are as followings. 1. The effect of inoculation with tetragonal polyhedra of cytoplasmic polyhedrosis virus on the rate of infective induction with hexagonal polyhedron virus and with hexagonal plus tetragonal polyhedron viruses in the larvae from moths infected with hexagonal polyhedron virus was studied. Infection rate was higher by 40 to 60 percent in the larvae from infected female group than in tile larvae from noninfected female group. 2. In the studies of the effect of formalin-feeding on the induction of infection with hexagonal polyhedron virus, infection rate was higher by 40 percent in the larvae from infected female group than in the larvae from noninfected female group. However, there was no significant difference in the infection rates between the two formalin-concentration groups. 3. The effect of cold treatment on the induction of infection with hexagonal polyhedron virus was studied. Infection rate was higher by 50 percent in the larvae from infected female group than ill the larvae from noninfected female group. No difference was found in the infection rates of the two treatment groups of 12 and 48 hours. 4. The phenomena of induction and interference were studied by observing rate of infection with hexagonal polyhedron virus induced by the inoculation with tetragonal polyhedron virus. The degree of interference of primary hexagonal polyhedron virus by secondary tetragonal Ployhedron virus was increased as the dosage of secondary virus was increased. At the concentration of 1${\times}$10$\^$8/m1 of the secondary virus, the degree of interference was similar to. that of control group. On the other hand, infection with tetragonal polyhedron virus at low concentration was interfered by the primary virus. At the concentration of 1N10f/m1 of tetragonal polyhedron virus, however, the rate of infection with tetragonal polyhedron virus was increased sharply, which is still lower by 30 percent than that of control group. 5. In the studies of induction and virulence enhancement, based on the 1ate of mixed infection with hexagonal and tetragonal polyhedron viruses, the highest difference of infection rate between experimental group and control group exceeded 40 percent when the concentration of tetragonal polyhedron virus was 1${\times}$10$\^$7/m1. However, the infection rate of control group was not affected by concentrations of tetragonal polyhedron virus.

• Korean Journal of Environmental Agriculture
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• v.5 no.2
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• pp.149-155
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• 1986

The fatty acid compositions of phospholipids extracted from leaves and leaf mitochondria, which were sampled from several horicultural plants grown under blue color-deficient sunlight (BCDS), were determined and compared with those from plants grown under natural white colored sunlight(WCS). It was found that the mitochondria isolated from plants grown under BCDS contained phospholipid whose degree of unsaturation in unit of number of double bonds per lipid molecule was remarkably higher than that from plants grown under WCS, the relative increment being $8{\sim}49%$. This was significantly larger than the relative increment, $4{\sim}8%$ for total phospholipid extracted from whole leaves grown under BCDS campared to WCS. This observation demonstrated that the blue light effect of sunlight on the chemical property of cellular membranes, as long as it was concerned with fatty acid composition, arose mainly at the mitochondrial membrane. Also observing that the degree of unsaturation of mitochondrial phospholipid was much lower than that of total phospholipid, it was interpreted that this was the consequence of rather active oxidative destruction of lipid-fatty acid components occuring in mitochondrial membrane by the reactive oxygen species, especially superoxide($O_2-$), which was known to be produced in mitochondrial inner membrane through the side reactions of the respiratory electron transport chain and also probably through the photosensitized reaction involving oxygen induced by blue colored light. Thus, it may be tentatively concluded that the extent of photosensitization in mitochondrial membrane could be considerably reduced under BCDS resulting in lowering of the $O_2-$ level in the respirating organelle The possible involvement of photodynamic action in membrane oxidation was also indicated by the fact that the typical fat-soluble antioxidant, ${\alpha}-tocopherol$, was found to be contained on a higher level in leaves under BCDS than those under WCS.

• The Korean Journal of Malacology
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• v.32 no.1
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• pp.45-54
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• 2016

To evaluate the applicability of cellular energy allocation (CEA) in the bivalves as a biomarker for the assessment of environmental contamination, the energy contents and energy consumption in several tissues of the Manila clam, Ruditapes philippinarum were analyzed. The contents of lipid, glucose, protein and electron transport system (ETS) activity in the foot, siphons, gills, and body of R. philippinarum exposed to crude oil-spiked sediments were measured at 1, 2, 4, 7, 10 days after exposure. The reserved energy (energy available, EA) in the lipid, glucose and protein decreased as contamination level and exposure time increased. In contrast, the ETS activity (energy consumed, EC) showed the reverse tendency. The order of available energy contents were foot > siphons > gill > body. Significant differences in both EA and EC were found only at the highest contamination level (58.3 mg TPAHs/kg DW). EA decreased significantly in the foot and gill at 1 day, in the body at 2 and 7 days after exposure. EC increased significantly in the body at 4 days after exposure. CEA showed higher sensitivity to the contamination than EA or EC. Especially, CEA in the foot and body decreased significantly at lower ranges of contamination level (as low as 6.5 mg TPAHs/kg DW) during 1 to 7 days after exposure. The CEA is more useful than EA or EC alone for the assessment of sediment contamination at lower level that acute toxicity could not be detected. CEA analyses in the body of R. philippinarum after 4 days' exposure to contaminated sediments seem to be the most sensitive and reliable.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.513-523
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• 2017

We evaluated the viability of phytoplankton along the salinity gradient in the flood and ebb tides of spring tide of February and the ebb tide of neap tide of March 2017 in the Seomjin River Estuary. Additional laboratory experiments were also conducted to determine the reason of the pH changes along the salinity gradient using the field natural sample in February. In field, saltwater was well mixed at downstream vertically and the salinity gradient was horizontally appeared toward upstream of freshwater zone. There were strong negative correlations between salinity and nutrient (nitrate + nitrite R=0.99, p<0.001, and silicate R=0.98, p<0.001), implying that those two nutrients of freshwater origin were gradually diluted with mixing the saltwater. On the other hands, relatively high phosphate concentration was kept in the stations of saltwater over 15 psu, indicating that it was caused by resuspended sediments of Gwangyang Bay and downstream by tidal water mixing.Among phytoplankton community structure in winter, Eucampia zodiacus have occupied to be c.a. 70 % in the most stations. Based on the field survey results for survivability of phytoplankton by phytoPAM instrument, there was positive correlations between salinity and chlorophyll a (R=0.82, p<0.001) and, salinity and active chlorophyll a (R=0.80, p<0.001), implying that the dominant marine diatom species may have significantly damaged in low salinity conditions of upstream. Also, maximum mortality rate of phytoplankton caused by low salinity shock was appered to be 75% in the upstream station. In particular, the pH in spring tides of February had tended to increase with high phytoplankton accmulated stations, suggesting that it was related with absorption of $CO_2$ by the photosynthesis of dominant diatom. In laboratory experiments, phytoplankton mass-mortality caused by low salinity shock was also occurred, which is confirmed with reducing the photosynthetic electron transport activity. Following the phytoplankton mass-mortality, bacteria abundance was significantly increased in 24 hours. As a result, the mass-proliferating bacteria can produce the $CO_2$ in the process of biodegradation of diatoms, which can lead to pH decrease. Therefore, marine phytoplankton species was greatly damaged in freshwater mixing area, depending on along the salinity gradient that was considered to be an important role in elevating and reducing of pH in Seomjin River Estuary.

• Radiation Oncology Journal
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• v.27 no.1
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• pp.35-41
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• 2009

Purpose: This study was designed to determine the optimum radiotherapy technique for internal mammary node (IMN) irradiation after breast-conserving surgery. Materials and Methods: We selected ten cases of early stage partial mastectomy for plan comparison. Five of the patients were treated to the right-side breast and the rest of the patients were treated to the left-side breast. For each case, four different treatment plans were made to irradiate the entire breast, IMNs and supraclavicular lymph nodes (SCLs). The four planning techniques include a standard tangential field (STF), wide tangential field (WTF), partially wide tangential field (PWT) and a photon-electron mixed field (PEM). We prescribed a dose of 50.4 Gy to the SCL field at a 3 cm depth and isocenter of the breast field. Results: The dose distribution showed clear characteristics depending on the technique used. All of the techniques covered the breast tissue well. IMN coverage was also good, except for the STF, which was not intended to cover IMNs. For the cases of the left-side breasts, the volume of the heart that received more than 30 Gy was larger (in order) for the WTF, PWT, PEM and STF. For radiation pneumonitis normal tissue complication probability (NTCP), the PWT showed the best results followed by the STF. Conclusion: Despite the variety of patient body shapes, the PWT technique showed the best results for coverage of IMNs and for reducing the lung and heart dose.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.111-115
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• 2013

The optimum synthetic conditions of poly(p-phenylphenol) by horseradish peroxidase in dioxane:water (80:20 v/v) mixtures were studied. The stability against thermal degradation and structural properties of the synthesized phenolic resins were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The synthetic yield of poly(p-phenylphenol) increased upon the increase of the amount of enzyme up to 0.25 mg HRP/mL, then leveled off for further increase of the enzyme usage. When sodium acetate (100 mM, pH 4~6) and sodium phosphate (100 mM, pH 7~9) were used as the buffering salts for the aqueous component (20% v/v), the synthetic yield of the resin increased at higher pH of the aqueous buffer. But when the pHs of the aqueous buffer were 6 and 9, the synthetic yield strongly depended on the types of the buffering salts; if sodium phosphate was used instead of sodium acetate at pH 6, the yield decreased by about 15% and if sodium bicarbonate was used instead of sodium phosphate, the yield decreased by almost 20%. When the pH range of the aqueous buffer was from 4 to 7, the addition of a radical mediator, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate) (ABTS), up to 2 mM improved the synthetic yield of the resin by about 10%. TGA experiments revealed that the thermal stability of the resin synthesized in dioxane:water (100 mM sodium phosphate, pH 9) (80:20 v/v) was high having the char yield of 47% upon the heating at $800^{\circ}C$. DCS results showed that the structures of the polymers synthesized in acidic aqueous buffers were different from those of the polymers synthesized in the basic aqueous buffers. However, all the synthesized resins were found to have the property of the thermosetting resins.