• Korean Journal of Poultry Science
• /
• v.33 no.4
• /
• pp.295-301
• /
• 2006

This study has been designed to evaluate the efficacy of MD in-ovo vaccination in broiler and to find the contamination level of MD virus in broiler farms. A nested PCR test was used to find the level of filed contamination of pathogenic MD virus in the commercial broiler farms. The positive rate of farms contaminated with pathogenic MD virus was 26.09%. And to evaluate the efficacy of MD vaccination, performance factors such as the mortality, feed conversion rate and body weight at market age has been recorded and compared among farms. There was no difference on these factors between vaccinated and non-vaccinated farms except performance. We need further investigation of the film with low performance index. The B/B ratio, which is common index for the evaluation of bursal changes, was calculated and compared between vaccinated and non-vaccinated group There were significant decreases of B/B ratio in the both group without any statistical difference between groups. The reason of decreased bursal size may be due to other infection such as IBD. From this study, we can know that the contamination rate of fm with pathogenic MD virus was very low and not different from previous study. However, the difference of the contamination rate in different locations recommends periodical monitoring on these areas.

• Investigative Magnetic Resonance Imaging
• /
• v.7 no.1
• /
• pp.31-38
• /
• 2003

Purpose : To analyze the serial changes of proton magnetic resonance (MR) spectra in the abscess and to determine the effect of the antibiotic treatment on the metabolite patterns. Materials and Methods : MR imaging and MR spectroscopy of an experimentally induced abscess were performed sequentially for four weeks at interval of one week in both the control group (n=5) and the antibiotic treatment group (n=5). On MR imaging, the shape and the size of the abscess were analyzed. On MR spectroscopy, the resonance peaks of metabolites were assigned on the basis of reported peaks in the literature. The metabolite ratios measured by using N-acetyl alanine as an external reference and by using lipid as an internal reference were compared in both the control and treatment g roups. Results : The abscesses were seen as cystic masses on MR imaging. On MR spectroscopy, the variable peaks of acetate, succinate and various amino acids, which are the metabolites of infection, were identified in the control and antibiotic treatment groups. The most frequent peak was that of acetate at 1.92ppm (70%). Both the peak ratios of acetate to lipid and acetate to external reference tended to decrease in the treatment group while the ratios did not change significantly in the control group. Conclusion : MR spectroscopy is useful not only for the diagnosis of abscess but also for monitoring the evolution of the abscess by using the acetate peak.

• Korean Journal of Ecology and Environment
• /
• v.34 no.3 s.95
• /
• pp.215-222
• /
• 2001

A statistical analysis was performed to evaluate relationships among the pollutant concentrations in non-urban area. The data obtained from two subcatchments in Hwa-Ong watershed during 1999 was used for correlation and regression analyses. Strong correlations were observed among the SS, COD, and TP, while it was not significant with TN. The reason fer weak correlation with TN might be that TN was high in dry-days and runoff in wet-days could not increase enough to change it substantially like in other pollutants. The correlations were stronger for the data in wet-days than in dry-days, and it was influenced by watershed characteristics. While TP-COD showed linear relationship from the regression analysis, SS-TP and SS-COD shelved intrinsically linear relationship between log-transformed TP and COD data and non-transformed SS data. The TP-COD showed strong relationship for all the combinations of monitored data, which implies that these two constituent concentrations varied in a similar pattern. The regression equations reported in the paper might be used to estimate one pollutant concentration from the other in pollutant loading estimates, and its application could be expanded to other non-urban watersheds if their characteristics are not significantly different from the study area. In water quality management projects, rigorous monitoring and its thorough evaluation are recommended to develop more reliable relationships among the pollutant concentrations which could be used in other area.

• Journal of the Korean Chemical Society
• /
• v.61 no.2
• /
• pp.51-56
• /
• 2017

N-nitrosamines are the nitroso compounds which are produced by nitrosation reactions of the secondary amine and nitrite under acidic conditions. Approximately 300 species of N-nitrosamine have been tested for carcinogenicity in laboratory experiments, with 90% of them demonstrated carcinogenic effects different animal species, including higher primates. In 1978, IARC classified NDMA and NDEA as Group 2A, and NDPA, NDBA, NPIP, NPYR and NMOR as Group 2B. In this study, we established pretreatment and analytical method for N-nitrosamines (NDMA, NDEA, NMEA, NDPA, NDBA, NPIP, NPYR and NMOR) in human urine for biological monitoring of N-nitrosamines. The analytes were extracted using solid phase extraction (SPE), then quantitative analysis was performed by LC-(APCI)-MS/MS. The accuracies of the established method were between 85.8~108.7% and precisions were lower than 20%. The limit of detection (LOD) were between 0.0002 (NDBA) and 0.0793 (NDMA) ng/ml. The linearity obtained was satisfying for the 8 N-nitrosamines, with a coefficient of determination ($r^2$) higher than 0.999. The mean concentrations of N-nitrosamines in the urine were 2.645 mg/g creatinine for NDMA, 0.067 mg/g creatinine for NDEA, 0.009 mg/g creatinine for NMEA, 0.011 mg/g creatinine for NDBA, 0.271 mg/g creatinine for NPIP and 0.413 mg/g creatinine for NPYR. NDPA and NMOR were not detected. It can be used as a instrumental methodology for evaluation and risk assessment of human exposure to N-nitrosamines for the further research.

• The Journal of Engineering Geology
• /
• v.30 no.1
• /
• pp.17-30
• /
• 2020

An optical televiewer is a geophysical logging device that produces continuous high-resolution full-azimuth images of a borehole wall using a light-emitting-diode and a complementary metal-oxide semiconductor image sensor to provide valuable information on subsurface discontinuities. Recently, borehole imaging logging has been applied in many fields, including ground subsidence monitoring, rock mass integrity evaluation, stress-induced fracture detection, and glacial annual-layer measurements in polar regions. Widely used commercial borehole imaging logging systems typically have limitations depending on equipment specifications, meaning that it is necessary to clearly verify the scope of applications while maintaining appropriate quality control for various borehole conditions. However, it is difficult to directly check the accuracy, implementation, and reliability for outcomes, as images derived from an optical televiewer constitute in situ data. In this study, we designed and constructed a modular fractured borehole model having similar conditions to a borehole environment to report unprecedented results regarding reliable data acquisition and processing. We investigate sonde magnetometer accuracy, color realization, and fracture resolution, and suggest data processing methods to obtain accurate aperture measurements. The experiment involving the fractured borehole model should enhance not only measurement quality but also interpretations of high-resolution and reliable optical imaging logs.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.33 no.2
• /
• pp.193-197
• /
• 2013

In this study, ultrasonic nonlinear characteristics in the heat-treated aluminum alloy have been evaluated. The nonlinearity of ultrasonic wave has been measured as the acoustic nonlinear parameter ${\beta}$, depending upon the amplitude ratio of the second-order harmonic and the fundamental frequency component of ultrasonic wave propagating through the materials. The parameter ${\beta}$ measurement has been carried out with the reflected signals from the back-wall of specimens at the same plane using the contact-type transducers. The heat-treatment, aging, has been achieved at $300^{\circ}C$ for various durations in the range of 1 to 50 hours. The tensile strength and elongation are obtained by the tensile test and then compared with the parameter ${\beta}$. There is a peak of the acoustic nonlinear parameter ${\beta}$ on 5 hours aging and the ${\beta}$ decreases thereafter, exhibiting closed relations with tensile strength and elongation. Also, the heat-treatment time showing peak in the parameter ${\beta}$ was identical to that showing severe change in the ${\sigma}-{\varepsilon}$ curve. These results suggest that the acoustic nonlinear parameter ${\beta}$ can be used for monitoring the strength variations with aging of aluminum alloys.

• Journal of Korean Society on Water Environment
• /
• v.31 no.1
• /
• pp.12-18
• /
• 2015

In this research, the hydrologic effects between a pre-existing urban landuse and low impact development (LID) applied conditions were compared and evaluated. The infiltration trench and tree box filter that were utilized in LID represent only 1% of the catchment area that they drain. Storm event monitoring were conducted from July 2010 to July 2014 on a total of 22 storm events in both LID sites. After LID, hydrological improvement was observed as the sites exhibited a delay (lag time) or reduction in the magnitude, frequency and duration of runoff and flow peaks as the rainfall progress. In addition, the maximum irreducible peak flow reduction for infiltration trench was found to be 61% and 33% for the tree box filter when rainfall was 40 mm and 30 mm, respectively. In designing LID, it is recommended to consider the storage capacity and catchment area, as well as the amount of rainfall and runoff on the site.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.5
• /
• pp.497-510
• /
• 2018

In this study, the decay resistance of larch wood, which was heat treated by superheated steam, was evaluated by the field decay test. During the field decay test of 12 months, non-treated wood has been severely damaged by termite, however, no visible damage has occurred in the preservative-treated wood and superheated steam heat-treated wood. Results of field decay test showed approximately 5% mass loss of the non-treated wood and the preservative-treated wood, and approximately 1% mass loss of the superheated steam heat-treated wood. After the field decay test for 12 months, the residual amount of preservatives remaining in the preservative-treated wood was lower than that before the field decay test. It was considered that the preservative was partially eluted during the field decay test, and the mass loss of the preservative-treated wood was thought to be similar to that of the non-treated wood. Through this study and additional long-term monitoring test, superheated steam heat treatment can be considered to be an environmental-friendly method to enhance the decay resistance of wood against rot fungi and/or insect without chemical treatment such as preservative injection.

• Journal of Science and Technology Studies
• /
• v.18 no.2
• /
• pp.7-41
• /
• 2018

The projects of citizen science which is originated from citizen data collecting action driven by governmental institutes and science associations have been implemented with different form of collaboration with scientists. The themes of citizen science has extended from the ecology to astronomy, distributed computing, and particle physics. Citizen science could contribute to the advancement of science through cost-effective science research based on citizen volunteer data collecting. In addition, citizen science enhance the public understanding of science by increasing knowledge of citizen participants. The community-led citizen science projects could raise public awareness of environmental problems and promote the participation in environmental problem-solving. Citizen science projects based on local tacit knowledge can be of benefit to the local environmental policy decision making and implementation of policy. These social values of citizen science make many countries develop promoting policies of citizen science. The korean government also has introduced some citizen science projects. However there are some obstacles, such as low participation of citizen and scientists in projects which the government has to overcome in order to promote citizen science. It is important that scientists could recognize values of citizen science through the successful government driven citizen science projects and the evaluation tool of scientific career could be modified in order to promote scientist's participation. The project management should be well planned to intensify citizen participation. The government should prepare open data policy which could support a data reliability of the community-led monitoring projects. It is also desirable that a citizen science network could be made with the purpose of sharing best practices of citizen science.

• Korean Journal of Social Welfare
• /
• v.37
• /
• pp.271-306
• /
• 1999

This study aimed to present a comprehensive case management model which might be helpful for social workers in community social welfare agencies who works with North Korean refugees for their psychosocial adjustment in South Korea. After being constructed, the model was put into practice upon North Korean refugees. This article described the whole process of model construction and its application. Detail steps taken in this research include: (a) The researcher had 20 unstructured individual interviews with 11 North Korean refugees in order to identify psychosocial problems that need social workers' intervention; (b) Based upon the problems identified through interviews and previous literature review, program components were identified and sorted out into two phases, one of which is therapeutic phase, the other is case management phase; (c) By interlocking the two phases, the researcher proposed a comprehensive case management model whereby North Korean refugees can get psychosocial services as well as linkage services in an interactive fashion; (d) The utility of the proposed model was examined by using a couple of North Korean refugees who initially showed complicated psycho-social-economic problems. The therapeutic phase employed a cognitive-behavioral approach. The case management phase consists of: assessment and diagnosis; service planning and resource identification; linking of clients to needed services; monitoring of service delivery; and evaluation. Although the program could not go through with because of the limited contacts with North Korean refugees for security reasons, the program was turned out to be very useful in helping North Korean refugees' settling-down in South Korea. Implications for the application of the proposed model was discussed along with limitations of this study.