• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.145-150
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• 2011

Presently, mass concrete structures are being built in federal and private projects of civil infrastructures and building structures. The hydration heat of mass concrete structures is the most important factor in the quality of concrete matrix and construction period. Moreover, internal cracks caused by hydration heat degrades durability, water tightness, and strength of concrete. To reduce hydration heat, it is necessary to blend belite cement (${\beta}-C_2S$) with industrial by-products (i.e. granulated slag and fly ash). In this experiment, 14 levels of binary binders and 4 levels of ternary binders were used to understand the effect of different replacement ratio on hydration heat, strength and microstructure (i.e. SEM and XRD) of mortar. Cumulative hydration heat at 28 days for the binary and ternary binders was affected by replacement ratio of fly ash and/or granulated slag. As fly ash content increased, hydration heat decreased. As granulated slag content increased, reduction rate of the hydration heat was lower than when fly ash was used. Especially, the hydration heat of ternary binder blended with 40% flyash and 30% granulated slag showed about 50% of hydration heat from using belite cement (P). The study results showed that the temperature rise of concrete matrix can be decreased by using blended belite binders producing low hydration heat and reasonable strength.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.282-289
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• 2014

BACKGROUND: Methane($CH_4$) is considered as the secondmost potent greenhouse gas after carbon dioxide ($CO_2$). Methanogenesis is an enzyme-mediated multi-step process by methanogens. In the penultimate step, methylated Co-M is reduced by methyl Co-M reductase (MCR) to $CH_4$ involving a nickel-containing cofactor F430. The activity of MCR enzyme is dependent on the F430 and therefore, the bioavailability of Ni to methanogens is expected to influence MCR activity and $CH_4$ production in soil. In this study, different doses of EDTA(Ethylene Diamine Tetraacetic Acid) were applied in flooded soils to evaluate their suppression effect on methane production by chelating Ni of methanogenesis cofactor. METHODS AND RESULTS: EDTA was selected as chelating agents and added into wetland and rice paddy soil at the rates of 0, 25, 50, 75, and $100mmol\;kg^{-1}$ before 4-weeks incubation test. During the incubation, cumulative $CH_4$ production patterns were characterized. At the end of the experiment, soil samples were removed from their jars to analyze total soil Ni and water-soluble Ni content and methanogen abundance. Methane production from 100 mmol application decreased by 55 and 78% in both soils compared to that from 0 mmol. With increasing application rate of EDTA in both soils, water-soluble Ni concentration significantly increased, but total soil Ni and methanogen activities showed negative relationship during incubation test. CONCLUSION: The decrease in methane production with EDTA application was caused by chelating Ni of coenzyme F430 and inhibiting methanogenesis by methyl coenzyme M reductase. Consequently, EDTA application decreased uptake of Ni into methanogen, subsequently inhibited methanogen activities and reduced methane production in flooded soils.

• Korean Journal of Head & Neck Oncology
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• v.22 no.2
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• pp.130-136
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• 2006

Introduction : The sensitivity of tumor cells to radiotherapy is a critical determinant of local control and potential cure in advanced head and neck squamous cell carcinoma(HNSCC). The emergence of radioresistant tumor cells is an obstacle to cancer therapy. Most radioresistant cells have a higher proportion of cells in the Sphase of the cell cycle and a lower apoptotic fraction than radiosensitive cells. HSV replication is increased in cells that have higher S-phase fractions. NV1066 is an oncolytic herpes simplex virus type-1 mutant. We hypothesized that NV1066 replication and cytotoxicity are increased in radioresistant cells. The purpose of this study is to evaluate the antitumor efficacy of NV1066 to treat radioresistant HNSCC. Methods : Radioresistant cells were selected by treating five HNSCC cell lines with repeated conventional fractionated doses of radiation(2Gy/day), using a Cs-137 irradiator, up to a cumulative dose of 70Gy. Clonogenic cell survival and S-phase fractions were compared between radioresistant and parental radiosensitive cells. The two cell populations were then treated with NV1066 to examine viral replication, by the viral plaque assay and viral cytotoxicity. Results : Fractionated irradiation resulted in the selection of radioresistant cells. Radioresistant cells had a higher S-phase fraction(42.9%) compared to parental cells(26.2%). NV1066 replication in radioresistant cells was 7.4 times higher than in parental cells(p<0.01). Treatment with NV1066 resulted in increased cytotoxicity of 24.5% in radioresistant cells compared to parental cells(p<0.05). Conclusion : NV1066 showed increased viral replication and cytotoxicity in radioresistant HNSCC cell lines. These findings suggest a potential clinical application for this oncolytic viral therapy as treatment for radioresistant head and neck cancers.

• Journal of Life Science
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• v.22 no.6
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• pp.788-793
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• 2012

High concentration of antibiotics has been used to treat the outbreak of edwardsiellosis caused by Edwardsiella tarda in aquaculture. However, not all of the bacteria have been killed with high concentrations of antibiotics treatment by the formation of persister cells with a dormant state. The main objective of this study was to kill persister cell using antibiotics with the addition of natural plant compounds. Antibiotics used in this study consist of 100 mg/ml florfenicol and 100 mg/ml amoxicillin. Ten natural plant compounds with persister cell inhibitor activity to E. coli were obtained from Protein Engineering and Systems Biology Lab. of Sungkyunkwan University. The persister cell inhibition activities of those natural plant compounds were evaluated in test tube. Concentrations of the antibiotics were in the ranges of 25~200 ${\mu}g/ml$. The persister cell formation was observed after 16 hours of culture. Persister cells were killed by antibiotics with natural plant compounds. Among ten natural plant compounds, Gynostemma pentaphyllum, Mallotus japonicus, and Orixa japonica showed persister cell formation inhibition activities. The optimal concentrations of G. pentaphyllum, M. japonicus, and O. japonica for the inhibitor of persister cell formation were 100 ${\mu}g/ml$, 100 ${\mu}g/ml$, and 200 ${\mu}g/ml$, respectively. In vivo study was carried out to evaluate the effect of the antibiotics with natural plant compounds using aquacultural fish, olive flounder, as test animals. G. pentaphyllum, M. japonicus, and O. japonica of 30 ${\mu}g/ml$, 10 ${\mu}g/ml$, and 10 ${\mu}g/ml$ with antibiotics reduced cumulative mortalities, showing the effectiveness of persister cell inhibition.

• Journal of Preventive Medicine and Public Health
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• v.21 no.1 s.23
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• pp.89-98
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• 1988

While there have been not a few reports on the seroepidemiological characteristics of hepatitis B virus (HBV) infection in Korea, most of them, however, have had several limitations; operational definition of HBV infection, validity of detection methods of HBV serologic markers, size of the study population, and confirmation of the vaccination history against HBV, etc. In order to avoid such limitations, authors randomly selected 1,495 healthy adults among the 217,511 insured (target population) of Korean Medical Insurance Corporation, living in seoul, and tested HBV serologic markers by RIA method and conducted direct interview to them. Although HBV serologic markers (HBsAg, anti-HBs and anti-HBc) of all the subjects were tested, 392(26.2%) of interview failure cases and 361 vaccinee were excluded from the actual population. Finally, the serologic markers tested of 742 nonvaccinee (study population) only were analysed for the seroepidemiologic observation of the natural infection of HBV. The seroepidemiological characteristics of HBV infection in Korea were as follows ; 1. Point prevalence of HBs antigenemia was 11.7(9.1{\sim}14.3)% in male, which was slightly higher than that of female, 9.5($3.7{\sim}15.3$)%. This level was one of the highest among those of Asian-Pacific countries. Decreasing tendency of HBsAg prevalence alter the age of 50 was observed, which seems to be due to selective attrition of HBV chronic carriers among the healthy adults and/or to the limited-lasting duration of the HBs antigenemia, in part. 2. Point prevalence of anti-HBc(78.8% in male,50.9% in female) was higher than that of anti-HBs(65.2% in male,46.6% in female), respectively. And both of them were higher in male than in female. Increasing tendency of the prevalence of both antibodies was observed by age, which seems to be largely due to recurrent infection in adults and to some cumulative effect, in part, of their relatively longer-lasting duration. 3. The level of HBV infection defined by positive for at least one of the 3 serologic markers of HBV by RIA method was 84.7($81.8{\sim}87.6$)% in male and 61.2($51.9{\sim}70.5$)% in female, which was also one of the highest among those of Asian-Pacific countries. The proportion of susceptible population to HBV infection among healthy adults was 15.3% in male and 38.8% in female. 4. The relative frequency of current or past infection and chronic carrier among HBV infected person was estimated. The currently or past infected was estimated 75.7% in male and 71.8% in female, and chronic carrier state, 13.8% in male and 14.1% in female. The analysis of the geometric mean of the antibody titer in anti-HBs positive sera indicated also to be compatible with the above findings, suggesting that active, even though inapparent, infection of HBV occur so frequently among healthy adults in Korea.

• Journal of Soil and Groundwater Environment
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• v.6 no.4
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• pp.3-11
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• 2001

To select a suitable indigenous plant for the phytoremediation of TNT contaminated soil, eight representative species of native grasses were tested to identify TNT toxicity thresholds. The threshold was determined based on various factors including cumulative seed germination, root and shoot length, fresh biomass, and the amount of water uptake under various TNT concentrations. Phytotoxic effect of TNT on plants was increased with the increase in TNT concentration but the degree was varied between grass species. Concentrations up to 60-80mgTNT/liter did not affect germination of Abutilion avicennae, Echinochioa crusgalli var. frumentacea, and Aeschynomene indica. Phytotoxicity threshold inhibition (50%) of Abutilion avicennae, schinochioa crusgalli var. frumentacea, Aeschynomene indica were 5-40mgTNT/liter for root length, 50-73mg TNT/Liter for shoot length and 68-99mgTNT/Liter for fresh biomass during 14 days of seedling exposure. Root and shoot growth as well as fresh biomass decreased as TNT concentration increased. In addition, the amount of water uptake decreased with increasing TNT concentration in Abutilion avicennae and Aeschynomene indica. Comparison of toxicity thresholds for the tested grass species showed that sensitivity of plants to TNT was in the order of root length > shoot length > fresh biomass > germination rate. From these results, we concluded that Abutilion avicennae and Aeschynomene indica had tolerance to TNT among the species tested.

• Radiation Oncology Journal
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• v.10 no.2
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• pp.237-245
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• 1992

Five hundred and fifty patients treated for carcinoma of the uterine cervix at the Department of Therapeutic Radiology, Seoul National University Hospital from 1979 to 1986, were analyzed retrospectively for late rectal complications. Of them, 468 patients received primary radiotherapy for the cervix cancer in intact uterus, and the other eighty two patients were treated postoperatively. The cumulative incidence of radiation induced rectal complication of grade 2 or 3 was 6.7% at five years. The mean rectal dose for the group of patients with complication was higher than the group without complication, and the difference was statistically significant (p<0.01). But relationship between mean rectal dose and severity of complication was not found. The frequency of complication (grade 1, 2, 3) increased as a function of radiation dose to rectum; from 16.1% for patients with rectal dose less than 6,000 cGy to 71.2% for patients with rectal dose higher than 8,000 cGy. Among various factors analyzed, history of diabetes mellitus, number of intracavitary irradiation, size of ovoid, retroflexion of uterus and the total dose delivered to rectum turned out to have significant effect on the complication.

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.247-252
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• 2010

This study was carried out between 2008 and 2009 in four dairy farms to investigate the effect of feeding of whole crop barley silage on the reproductive performance of Holstein heifers. Two diets, mixed hay or whole crop barley silage separately from concentrate were fed 6-month old Holstein heifers (=37). In control group (=CON), heifers (n=16) were fed 6 kg (/head) mixed hay and 4 kg (/head) commercial diet. In whole crop barley silage group (=WBS), heifers (n=21) were fed 10 kg (/head) whole crop barley silage, 4 kg (/head) mixed hay and 2 kg (/head) commercial diet. To manage body weight gain, the body condition score of heifers were measured every month. The results obtained were as follows: 1. Body weight in CON and WBS heifers at 13-, 14-, 15- and 17-month old were $340{\pm}17.9$ and $342{\pm}13.6\;kg$, $356{\pm}15.7$ and $366{\pm}14.7\;kg$, $382{\pm}13.1$ and $387{\pm}14.4\;kg$, and $429{\pm}15.0$ and $417{\pm}10.3\;kg$, respectively. 2. Body condition score in CON and WBS heifers at 9-, 12-, 15- and 17-month old were $2.88{\pm}0.04$ and $2.80{\pm}0.04$, $2.88{\pm}0.04$ and $2.80{\pm}0.04$, $2.89{\pm}0.08$ and $3.00{\pm}0.07$, and $2.89{\pm}0.08$ and $3.00{\pm}0.07$, respectively. 3. Average age of sexual maturity in CON and WBS heifers were $437.3{\pm}9.9$days and $939.6{\pm}12.5$days, WBS group heifers were significantly shorter (p<0.05) than CON group heifers. 4. First-service conception rates in CON or WBS group were 81.3% (13/16) and 66.7% (14121), respectively, and cumulative conception rate to 2nd artificial insemination were 87.5% for CON and 85.7% for WBS group. Conception rate was not different between treatments.

• Women's Health Nursing
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• v.1 no.2
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• pp.174-199
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• 1995

This study examined the antenatal care known as Taekyo. The sample consisted of 795 women and 564 men who had be seen in the antenatal care unit, delivery room, or postpartal care unit of general hospitals in Korea between March 20 and April 22, 1995. Data were collected using the "Taekyo questionnaire for childbearing women" and "Taekyo questionnaire for husbands of childbearing women" developed by researchers. Data were self-reported. Data were analyzed using the SPSS PC+ program, and descriptive statistics, T-test, ANOVA, Pearson correlation coefficient were applied. The results of this study were as follows : 1. Encouragement to practice Taekyo was at a relatively high level. Items on Taekyo encouraging behaviors had a mean score of 3.51(33 items 5 point scale). According to the five categories of Taekyo encouraging behaviors, subjects indicated they practice "food intake(mean score 4.02)". "praying(mean score 3.78)", "cumulative virtuous deeds (mean score 3.58)". "mind and body management(mean score 3.47)", "maternal fetal interaction(mean score 3.15)". 2. The childbearing women's practices related to forbidden behaviors by Taekyo were relatively high. Item on forbidden behaviors by Taekyo had a mean score 3.71(43 items 5 point scale). According to the five categories of forbidden behaviors by Taekyo, subjects indicated they practiced "voluntary abstention of drugs(mean score 4.78)," avoiding behaviors(mean score 4.78)," avoiding behaviors(mean score 3.77), "good behaviors(mean score 3.71)", "taboo on fetal death tendency (mean score 3.53)", "taboo on certain intake(mean score 3.47)". 3. The practice score of husbands for childbearing women which related to Taekyo behaviors were relatively high. Item on Taekyo behaviors had a mean score 3.59(33 items 5 point scale). According to the six categories of Taekyo behavior, subjects indicated they practiced "mind and body management(mean score 3.94)", "praying(mean score 3.80)", "support of women’s practice related to Taekyo(mean score 3.66)", "good behaviors(mean score 3.58)", "continency(mean score 3.33)", "paternal fetal interaction (mean score 3.19)". 4. On the childbearing women's perception of Taekyo, most of the subjects(88%) had confidence in the positive effects of Taekyo on Child development. The result showed that the childbearing couples practiced Taekyo behavior relatively often and sincerely and most of the childbearing women had a positive perception of Taekyo's effect on prenatal child development.

• Fire Science and Engineering
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• v.25 no.1
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• pp.42-49
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• 2011

In the high temperature situation like in a fire, the high strength of concrete (HSC) has extreme danger named explosive spalling. It is assumed that the major cause of explosive spalling is water vapour pressure inside concrete. This paper examines the effect of the compressive strength and the moisture content on the initial occurrence of explosive spalling. For the effective experiment of the initial explosive spalling, the curve of ISO834 temperature profile is applied on the basis of 15 minute and 30 minute. As a result, the more increase the compressive strength and the moisture content, the more increase the occurrence and phenomenon of explosive spalling. This paper analyzes the territory of explosive spalling depending the compressive strength and the moisture content. The explosive spalling is not examined in the case of the compressive strength 50~100 MPa and the moisture content below 3% and the compressive strength over 100 MPa and the moisture content below 1%. Also, due to the HSC, which makes it more difficult to transport vapour and moisture, very high vapour-pressure may occur close to the surface, there is a greater risk that HSC spalls compared with normal strength concrete (NSC).