• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.547-553
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• 2017

In the current medical field, lead is widely used as a radiation shield. However, the lead weight is very heavy, so wearing protective clothing such as apron is difficult to wear for long periods of time and there is a problem with the danger of lethal toxicity in humans. Recently, many studies have been conducted to develop substitute materials of lead to resolve these problems. As a substitute materials for lead, barium(Ba) and iodine(I) have excellent shielding ability. But, It has characteristics emitting characteristic X-rays from the energy area near 30 keV. For patients or radiation workers, shielding materials is often made into contact with the human body. Therefore, the characteristic X-rays generated by the shielding material are directly exposured in the human body, which increases the risk of increasing radiation absorbed dose. In this study, we have developed the FLUKA transport code, one of the most suitable elements of radiation transport codes, to remove the characteristic X-rays generated by barium or iodine. We have verified the reliability of the shielding fraction of the structure of the structure shielding by comparing with the MCPDX simulations conducted as a prior study. Using the MCNPX and FLUKA, the double layer shielding structures with the various thickness combination consisting of barium sulphate ($BaSO_4$) and bismuth oxide($Bi_2O_3$) are designed. The accuracy of the type shown in IEC 61331-1 was geometrically identical to the simulation. In addition, the transmission spectrum and absorbed dose of the shielding material for the successive x-rays of 120 kVp spectra were compared with lead. In results, $0.3mm-BaSO_4/0.3mm-Bi_2O_3$ and $0.1mm-BaSO_4/0.5mm-Bi_2O_3$ structures have been absorbed in both 33 keV and 37 keV characteristic X-rays. In addition, for high-energy X-rays greater than 90 keV, the shielding efficiency was shown close to lead. Also, the transport code of the FLUKA's photon transport code was showed cut-off on low-energy X-rays(below 33keV) and is limited to computerized X-rays of the low-energy X-rays. But, In high-energy areas above 40 keV, the relative error with MCNPX was found to be highly reliable within 6 %.

• Parasites, Hosts and Diseases
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• v.24 no.2
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• pp.187-193
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• 1986

Enzyme-linked immunosorbent assay(ELISA) using crude and affinity-purified antigens of adult worms of Paragonimus westermani was performed for infected cat sera with different worm burden, from preinfection to 18th week after infection. Crude antigen was used with supernatant of homogenated worms by freezing-thawing method, and the supernate was centrifuged for 1 hour at 10,000 rpm at $4^{\circ}C$. Affinity-purified antigen(antibody-bound antigen) was prepared from fractions(bound and unbound) of crude antigen by affinity chromatography on CNBr-activated sepharose 4B, and IgG as a ligand was prepared from paragonimiasis cat serum(6 months infected) obtained by ammonium sulfate ($40%{\sim}45%$ saturated) precipitation method. By SDS-PAGE, crude antigen showed 22 polypeptide fractions while purified antigen showed 4 fractions: 36, 400, 34, 700, 27, 600 and 11, 500 in molecular weights. All cats were divided into five groups($G_1-G_5$) by different worm burdens. The mean of recovered worms(${\pm}SD$) and the number of cats in each group are as follows: $G_1$, 2 worms(0) and 4 cats; $G_2$, 4.75 (${\pm}0.66$) and eight; $G_3$, 10.75(${\pm}1.92$) and four; $G_4$, 23.20(${\pm}3.43$) and five; $G_5$, 48(${\pm}12.63$) and five cats. The results were summarized as follows: 1. The antibody levels(OD value) increased by worm burden in $G_1$ to $G_4$ generally. However, individual antibody levels were not exactly related with worm burden in all groups, especially there was a wide difference in $G_4$ and $G_5$. These results suggested that the worm burden in $G_4$ (about $20{\sim}30$ worms) is enough to produce antibody maximum in cats of $2{\sim}3kg$ weight. 2. The antibody levels increased significantly(p<0.05) compared to control sera at the 3rd week in $G_1$ and $G_2$, at the 2nd week in $G_3$, and at the 1st week in $G_4$ and $G_5$. Especially in the 4th week, OD value increased more in $G_1$(p<0.01) and in $G_2$ to $G_5$(p<0.001). In the pattern of antibody levels by ELISA in each group, OD in $G_1$ increased to the 18th week continuously, in $G_2$ OD was maintained same after the 16th week, but in $G_3$ it decreased after the 16th week, and it was maintained same in $G_4$ and $G_5$ after the 14th week. 3. The antibody levels by ELISA with the affinity-purified antigen were higher than those with crude antigen in all groups generally. Especially, the difference of OD values between two antigens was larger from the 4th to the 10th week. In $G_1$ and $G_2$ OD with purified antigen was higher than that with crude one to the 18th week. It was also higher in $G_3$ than that with crude antigen to the 16th week and OD of $G_4$ and $G_5$ were higher before the 14th week than that with crude antigen, however became lower at the 16th week. Consequently, the antibody level in ELISA with affinity-purified antigen was more sensitive at the early weeks after infection and in light infection groups than that with crude antigen.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.1
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• pp.24-30
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• 1981

A pot Experiment and a field investigation were carried out in order to obtain some information on the ammonia volatilization and nitrogen absorption by paday rice plants in relation to the potassium application and roots growth. Results obtained were as follows ; 1. Urea application to the polt where potassium was added and rice plant was grown increased the ammonia volatilization at the beginning, but in the latter stage, the volatilization gradually decreased below that of no potassium plot. 2. Total nitrogen absorbed by rice plant, however, was much greater from the potassium added plot than no potassium and pH of the wet soil was lower in the former treatment than in the latter. 3. The application of urea presumably caused greater raise of soil pH and higher ammonia valatilization from the potassium added plot than the no potassium at the beginning, but the active growth of plants and raveneous absorption of N by the plants at the later stage of plant growth resulted in lower ammonia volatilization and lower pH in the potassium added plot than no potassium plot. 4. When the penetration of rice roots was restricted, pH of the wet soil was lower in the plot where potassium added than no potassium, and so was the ammonia volatilization. 5. Under high pH condition of paddy soil, a heavier basal application of potassium chloride or potassium sulfate may reduce the ammonia volatilization particulary in the early growth period of paddy rice when the nutrient absorption by plant is insignificant. However, under an acid normal soil, it may cause ammonia loss through raise of soil pH at the early growth of paddy rice.

• Journal of Food Hygiene and Safety
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• v.4 no.2
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• pp.119-132
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• 1989

Gamma irradiation as a new physical treatment was applied to comparative investigates with a conventional ethylene oxide fumigant on the microbiological and physicochemical qualities of selected spices and dry vegetables such as powdered red pepper, black pepper, welsh onion, onion, garlic, carrot, korean cabbage and instant ramyon soup. The microorganisms contaminated in the sample, including total viable count, thermophilic bacteria, aerobic spore and fungi counts between the $10^4\;to\;10^6/g$ range. Coliforms were found only in black pepper and welsh onion powder as the $10^2\;to\;10^3/g$ level. A radiation dose of 7 to 10 KGy were sterilized completely to the contaminated microorganisms, while ehthylene oxide (E.O.) fumigation reduced of them to the $10^3/g$ level. An optimum dose of irradiation was less detrimental than E.O. fumigation to the physicochemical properties of the sample. Sensory evaluation after three months of storage at room temperatures showed that the overall acceptability of irradiated sample was higher than that of the non treated control as well as E.O. fumigated samples. Comparison gamma irradiation with E.O. gas treatment showed that E.O. treatment was less effective than radiation in cotrolling microbial contamination of spices and vegetables.

• Journal of Yeungnam Medical Science
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• v.8 no.2
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• pp.52-62
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• 1991

The toxic effect of azalea extract, expecially on cardiovascular system, is relatively unclear. The purpose of this study is to study the possible underlying mechanism and effect of toxic ingredient of azalea on cardiovascular system. The 71 healthy rabbits were divided into 10 groups : In group as preliminary study ; 4cc of normal saline was administered intravenously(N) ; 0.7gm/kg and 1.0gm/kg of azalea extract was administered respectively in the same route, volume(A1, A2) ; atropine was administered intravenously(A) ; after pretreatment with atropine(0.04mg/kg) to block parasympathetic system, azalea extract was injected like the above groups(AA1, AA2) ; normal saline, 0.7gm/kg and 1.0gm/kg of azalea extract were administered respectively with 0.2cc(1 : 1000) epinephrine(E0,E1,E2). We measured the following indices at I minute interval during first 10 minutes and then 10 minute interval during next 30 minutes : RR interval, QTc interval, maximal systolic and diastolic pressure drop with occuring time and presence of significant arrhythmia. The results were as follows : 1. The changes of RR interval, QTc interval were significantly increased in groups by Azalea extract. The blood pressure change was significantly decreased in groups by Azalea extract. There were no significant differences according to dosage of Azalea extract. 2. The changes of RR interval, blood pressure were significant differences between administration of atropine and Azalea extract after pretreatment with atropine, but not in the change of QTc interval. 3. There were no significant differences in the change of RR interval, ATc interval, blood pressure drop according to pretreatment with atropine. 4. The interaction between epineprine and Azalea extract was not noted by the effect of epineprine itself. 5. The ST change by 0.7gm/kg, 1.0gm/kg of Azalea extract was revealed in 1 case(14.0%), 7 case(100%), respectively. 6. Most of all cases with arrhthymia, ventricular tachycardia, ventricular fibrillation, were noted in the group by epineprine, except one case by Azalea extract(1.0gm/kg). It was idioventricular rhythm. In conclusion, azalea extract has negative inotropic and chronotropic effect with arrhythmogenic potential possibly through direct myocardial ischemia or injury but we cann't be absolutely exclusive of actions of autonmic nervous system, especially parasympathetic nervous system.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.354-364
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• 2020

This study was conducted to examine the potential of inducing salinity stress on cylindrical paper pot tomato seedlings to inhibit overgrowth. Potassium fertilizers, sulfate of potash (K₂SO₄), muriate of potash (KCl), and monopotassium phosphate (KH₂PO₄), were prepared as two solutions of (5 and 10) dS·m^-1 salinity level, respectively, to investigate the influence on tomato (Lycopersicon esculentum Mill.) seedling growth. We also investigated the adaptability and survivability of treated tomato seedlings with high-salinity potassium (10 dS·m^-1 KCl) to harsh environmental conditions (water deficit, low temperature, and storage conditions). Repeated addition of high-salinity level KCl, K₂SO₄, or KH₂PO₄ markedly decreased the dry matter of shoot and root, leaf area, and net assimilate rates (NAR) but increased the stem diameter of seedlings. Among the three sources, the relative growth rate of plant height (RGR_H) was most sensitive to KCl addition; increasing salinity levels of KCl solution decreased the RGR_H of seedlings. The compactness, which directly reflects the stocky growth index, increased in KCl or KH₂PO₄ treatments. After a week's water deficit, severely wilted seedlings were observed in control seedlings (untreated with KCl), but no wilted seedlings were observed in the KCl treated seedlings, and the relative water content (RWC) of the untreated seedlings significantly decreased by 23 %, while that of the pretreated seedlings only decreased by 8 %. The increase in ion leakage of KCl treated seedlings at low temperatures was less than that of untreated seedlings. Furthermore, there was far lower damage proportion on pretreated seedlings at (9, 12, and 15)℃ storage temperatures after 20 days, compared with on unpretreated seedlings. Our results suggest that high-salinity potassium fertilizer, especially KCl, is effective in preventing tomato seedling overgrowth, while it also improves tolerance.

• Journal of Korean Society of Forest Science
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• v.81 no.1
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• pp.30-39
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• 1992

Artificial acid rain(pH2.0, 3.0, 4.0 and 5.0) was treated on the seeded pots of 4 species to examine its effects on germination, leaf injury and seedling growth. Aluminum ammonium sulfate solution (0.5, 1.0 and 2.5mM) and artificial acid rain (pH3.0, 4.0 and 5.0) were treated on the seeded germinators of 3 species to examine its effects on germination and radicle growth. Artificial acid rain was prepared by diluting sulfuric acid with ground water and ground water(pH6.5) was used as control. Artificial acid rain was sprayed to seeded pots three times per week. About 5mm of artificial acid rain was treated each time from early April to early October, 1991. Germination, seedling establishment, radicle growth, leaf injury and seedling growth were measured and compared among the treatments. The results were summarized as follows 1. Germination, seedling establishment rate of Pinus densiflora were highest on the pH5.0 pot whereas those of Ailanthus altissima was highest on the control pot, and those of Magnolia sieboldii showed the highest value on the pH3.0 pot. 2. The differences in seedling height of Pinus densiflora and Pinus rigida were significant among the treatment levels of acid rain, whereas those of Magnolia sieboldii and Ailanthus altissima were not significant. Seedling heights of Pinus densiflora and Pinus rigida were highest on the pH3.0 pot, and that of Magnolia sieboldii was highest on the pH4.0 pot, and that of Ailanthus altissima was highest on the control pot. 3. Seedling dry weights of Pinus densiflora. Pinus rigida, and Ailanthus altissima differed significantly among the treatments, but that of Magnolia sieboldii did not differ. Highest seedling dry weights of Magnolia sieboldii and Ailanthus altissima were observed on the pH4.0 pot, and that of Pinus densiflora was observed on the pH3.0 pot, and that of Pinus rigida was observed on the pH5.0 pot. 4. With decrease of pH value of artificial acid rain, the number of injured needle and injured individual tended to be increased. 5. The differences in effects of soil acidity were highly significant among the treatments for all species. 6. Radicle growth of Pinus densiflora differed significantly among pH levels and aluminum concentrations.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.751-755
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• 2005

Carbon dioxide, included in the flue gas from the combustion of fossil fuel, was known as a representative green house gas and various removal and utilization technologies of it has been studied for the prevention of global warming. This study was performed as an effort to find out a method to reuse carbon dioxide separated from flue gas by magnetite powder. Magnetite powder was synthesized using various oxidizers and alkalinity controlled aqueous solutions of $FeSO_4{\cdot}7H_2O$ and NaOH at 50, 80, 90, $100^{\circ}C$ and analyzed by XRD and SEM. The analysis results showed that magnetite powder synthesized at higher alkalinity and temperature had crystalline spinel and cubic structure. The reduction by hydrogen and the oxidation by carbon dioxide of synthesized powder were studied by TGA. The results showed that magnetite powder synthesized at low alkalinity and temperature was non-cubical amorphous but crystalline and cubical at high alkalinity and temperature. Comparing magnetite powders synthesized using oxidants(air and oxygen) and nitrogen, magnetite powder using more oxygen containing oxidant synthesized more crystalline magnetite powder. The experimental results of redox reaction of the synthesized magnetite powder showed that the reduction by hydrogen and the oxidation by carbon dioxide were seldom observed below $400^{\circ}C$ and observed well at $500^{\circ}C$. Magnetite powder synthesized at $100^{\circ}C$ and alkalinity(molal concentration ratio of $FeSO_4{\cdot}7H_2O$ to NaOH) of 2.0 using $O_2$ showed the highest reduction of 27.15 wt％ and oxidation of 26.73 wt％, especially at reaction temperature of $500^{\circ}C$.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.211-221
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• 2010

Proteoglycan is highly hydrophilic and negatively charged which enable them attract the water. The objective of study was to investigate the effects of Proteoglycan on microtensile bond strength of dentin adhesives and on architecture of dentin collagen matrix of acid etched dentin by removing the chondroitin sulphate attached on Proteoglycan. A flat dentin surface in mid-coronal portion of tooth was prepared. After acid etching, half of the specimens were immersed in 0.1 U/mL chondroitinase ABC (C-ABC) for 48 h at $37^{\circ}C$, while the other half were stored in distilled water. Specimens were bonded with the dentin adhesive using three different bonding techniques (wet, dry and re-wet) followed by microtensile bond strength test. SEM examination was done with debonded specimen, resin-dentin interface and acid-etched dentin surface with/without C-ABC treatment. For the subgroups using wet-bonding or dry-bonding technique, microtensile bond strength showed no significant difference after C-ABC treatment (p > 0.05). Nevertheless, the subgroup using rewetting technique after air dry in the Single Bond 2 group demonstrated a significant decrease of microtensile bond strength after C-ABC treatment. Collagen architecture is loosely packed and some fibrils are aggregated together and relatively collapsed compared with normal acid-etched wet dentin after C-ABC treatment. Further studies are necessary for the contribution to the collagen architecture of noncollagenous protein under the various clinical situations and several dentin conditioners and are also needed about long-term effect on bond strength of dentin adhesive.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.583-592
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• 2005

This experiment was conducted to determine the effects of dietary copper levels on performance, carcass characteristics, and economical analysis in Hanwoo steers. Fifteen Hanwoo steers weighing about 300kg were randomly allotted into one of three treatments. The three treatments consisted of Control(7mg Cu/kg feed), TI(12mg Cu/kg feed) and TII(17mg Cu/kg feed). Copper was formulated with concentrate from copper sulfate($CuSO_4$) and animals were fed the diets supplemented with copper from 300kg untill about 630 kg of body weight. Dietary copper levels did not affect daily weight gain, feed intake and feed efficiency during the whole feeding period. Dressing percentage, rib eye area and backfat thickness were not different between animals fed the diets supplemented with copper. Animals fed the diets supplemented with copper received the same B grade in yield grade. Animals fed the diets supplemented with copper received same marbling score. Beef color, fat color, texture and maturity were not affected by Cu supplementation in diet. Animals received the same first grade between treatments in quality grade. Animals fed the diet supplemented with 12mg of copper per kg diet was higher in profit by 13.3% than animals fed the control diet. According to these results, it may be concluded that performance, yield and quality grade were not affected by the Cu levels of 7 to 17mg per kg feed but crude income was enhanced when Hanwoo steers were fed the diet containing 12mg Cu/kg feed.