• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.241-247
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• 2013

AOAC Mouse Bioassay Analysis (MBA) has been the gold standard for the analysis of paralytic shellfish poisoning toxin (PSP toxin) for more than 50 years. However, this method has inaccurate limit of quantification and cannot be used to determine toxic profiles. An HPLC method (PCOX) was optimized for Korean shellfish to establish an alternative or supplementary method for PSP analysis and was intended to be used for the official monitoring and regulation of food. The recovery rate of the PCOX method was 83.5-112.1% and the limit of quantification for total toxin was about $8.6{\mu}g$/100 g. A long-term comparison study showed a good correlation of the PCOX results with the AOAC MBA results: the correlation factors were 0.9534 and 0.9109 for oyster and mussel matrices, respectively. The PCOX method may be used as an alternative or supplementary method for AOAC MBA to monitor the occurrence of PSP and to analyze PSP toxin profile in oysters and mussels.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.62-68
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• 2007

Concerns about endocrine disrupting chemicals emitted from humans and animals have been increased because these compounds are detected at very low levels in environment and adversely affect on indigenous fauna. To date, there is little information regarding the concentration of these compounds in animal wastes. In this study, the female hormones, $17\beta-estradiol$ (E2), estrone (E1) and estriol, were measured to provide baseline data in animal wastes. Samples were collected from animal waste storage, methane digester and sludge separated wastewater and analyzed by gas chromatography-mass spectrometry. To measure the mass ratios of estrogen to macronutrients, nitrogen and phosphorous were also determined. Sample collected from animal waste storage had the highest estrogen concentration (98.7 ${\mu}g/L$), while sludge separated wastewater had the lowest concentration (3.4 ${\mu}g/L$). The mean concentrations of E2 and E1 in waste storage sample were (6.8 ${\mu}g/L$) and (68.7 ${\mu}g/L$), respectively. In sludge separated wastewater, the mean concentration of both E2 and E1 were reduced to (2.6 ${\mu}g/L$) and (1.9 ${\mu}g/L$), respectively. However, estriol was not detected in any of the samples collected. Mean ratios of E2 and E1 to macronutrients were significantly different between the methane wastewater and sludge separated wastewater owing to elimination of solid particles.

• Journal of Food Hygiene and Safety
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• v.26 no.2
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• pp.142-149
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• 2011

An isocratic high performance liquid chromatography (HPLC) method for routine analysis of deoxynivalenol in noodles was validated and estimated the measurement uncertainty. Noodles (dried noodle and ramyeon) were analyzed by HPLC-ultraviolet detection using immunoaffinity column for clean-up. The limits of detection (LOD) and quantification (LOQ) were 7.5 ${\mu}g$/kg and 18.8 ${\mu}g$/kg, respectively. The calibration curve showed a good linearity, with correlation coefficients $r^2$ of 0.9999 in the concentration range from 20 to 500 ${\mu}g$/kg. Recoveries and Repeatabilities expressed as coefficients of variation (CV) spiked with 200 and 500 ${\mu}g$/kg were $82{\pm}2.7%$ and $87{\pm}1.3%$% in dried noodle, and $97{\pm}1.6%$ and $91{\pm}12.0%$ in ramyeon, respectively. The uncertainty sources in measurement process were identified as sample weight, final volume, and sample concentration in extraction volume as well as components such as standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. Deoxynivalenol concentration and expanded uncertainty in two matrixes spiked with 200 ${\mu}g$/kg and 500 ${\mu}g$/kg were estimated to be $163.8{\pm}52.1$ and $435.2{\pm}91.6\;{\mu}g$/kg for dried noodle, and $194.3{\pm}33.0$ and $453.2{\pm}91.1\;{\mu}g$/kg for ramyeon using a coverage factor of two which gives a level of statistical confidence with approximately 95%. The most influential component among uncertainty sources was the recovery of matrix, followed by calibration curve.

• Korean Journal of Remote Sensing
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• v.33 no.5_3
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• pp.855-866
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• 2017

Several research cases using remote sensing methods to analyze changes of storage and dynamics of groundwater aquifer were reviewed in this paper. The status of groundwater storage, in an area with regional scale, could be qualitatively inferred from geological feature, surface water altimetry and topography, distribution of vegetation, and difference between precipitation and evapotranspiration. These qualitative indicators could be measured by geological lineament analysis, airborne magnetic survey, DEM analysis, LAI and NDVI calculation, and surface energy balance modeling. It is certain that GRACE and InSAR have received remarkable attentions as direct utilization from satellite data for quantification of groundwater storage and dynamics. GRACE, composed of twin satellites having acceleration sensors, could detect global or regional microgravity changes and transform them into mass changes of water on surface and inside of the Earth. Numerous studies in terms of groundwater storage using GRACE sensor data were performed with several merits such that (1) there is no requirement of sensor data, (2) auxiliary data for quantification of groundwater can be entirely obtained from another satellite sensors, and (3) algorithms for processing measured data have continuously progressed from designated data management center. The limitations of GRACE for groundwater storage measurement could be defined as follows: (1) In an area with small scale, mass change quantification of groundwater might be inaccurate due to detection limit of the acceleration sensor, and (2) the results would be overestimated in case of combination between sensor and field survey data. InSAR can quantify the dynamic characteristics of aquifer by measuring vertical micro displacement, using linear proportional relation between groundwater head and vertical surface movement. However, InSAR data might now constrain their application to arid or semi-arid area whose land cover appear to be simple, and are hard to apply to the area with the anticipation of loss of coherence with surface. Development of GRACE and InSAR sensor data preprocessing algorithms optimized to topography, geology, and natural conditions of Korea should be prioritized to regionally quantify the mass change and dynamics of the groundwater resources of Korea.

• Journal of fish pathology
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• v.22 no.3
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• pp.263-273
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• 2009

There is an increasing number of reports describing Streptococcus parauberis as an important pathogen of cultured olive flounder Paralichthys olivaceus and starry flounder Platichthys stellatus in Korea. We tried to determine the effects of water temperature (14${^{\circ}C}$ and 21${^{\circ}C}$) on the pathogenicity in Streptococcal disease caused by S. parauberis. We have challenged 180 olive flounder by i.p injection to $2.0{\times}10^{7}$ live cells/fish. Mortality was monitored for 21 days post challenge. And histopathological characterizations as infection degree, tissue degeneration and/or bacterial distribution were investigated with H&E stain and in situ hybridization technique. Fifty percent and 16.7% of mortality occurred within 21 days at 21${^{\circ}C}$ and 14${^{\circ}C}$ water temperature, respectively. In most cases, the typical symptoms of olive flounder infected with S. parauberis were darkness of the skin, lethargy, mild abdominal distension cause by ascites, splenomegaly, congested liver and internal organs paleness. The pericardial sac contained large amounts of cloudy fluid. Numerous whitish nodules, which were variable in size and often confluent, were randomly scattered throughout the myocardium. Especially, pericarditis and/or myocarditis was observed in all tested fishes after death. Positive in reaction with S. parauberis were found in all tissues in situ hybridization analysis. The relative numbers of S. parauberis in heart were much more than in liver, spleen, kidney and stomach. We evaluated that S. parauberis strain causes serious damage in the pericardium, shortness of breath and the blood disorder. Therefore, pericarditis and myocarditis caused by S. parauberis were closely related to mortality of olive flounder.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.548-559
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• 1996

A series of performance measurements of positron emission tomography (PET) were performed following the recommendations of the Computer and Instrumentation Council of the Society of Nuclear Medicine and the National Electrical Manufacturers Association. We investigated the performance of the General Electric $Advance^{TM}$ PET. The measurements include the basic intrinsic tests of spatial resolution, scatter fraction, sensitivity, and count rate losses and randoms. They also include the tests of the accuracy of corrections: count rate linearity correction, uniformity correction, scatter correction and attenuation correction. GE $Advance^{TM}$ PET has bismuth germanate oxide crystals (4.0mm transaxial ${\times}$ 8.1mm axial ${\times}$ 30.0mm radial) in 18 rings, which form 35 imaging planes spaced by 4.25mm. The system has retractable tungsten septa 1mm thick and 12cm long. Transaxial resolution was 4.92mm FWHM in 2D and 5.14mm FWHM in 3D at the center. Average axial resolution in 2D decreased from 3.91mm FWHM at the center to 6.49mm FWHM at R=20cm. Average scatter fraction of direct and cross slices was 9.57%. Dead-time losses of 50% corresponded to a radioactivity concentration of $4.86{\mu}Ci/cc$ and a true count rate of 519 kcps in 2D. The accuracy of count rate linearity correction was 1.84% at the activity of $4.50{\mu}Ci/cc$. Non-uniformity was 2.06% in 2D and 2.93% in 3D. Remnant errors after scatter correction were 0.55% in 2D and 4.12% in 3D. The errors of attenuation correction were 6.21% (air), 0.20% (water), -6.32% (teflon) in 2D and 5.00% (air), 6.94% (water), 3.01% (teflon) in 3D. The results indicate the performance of GE $Advance^{TM}$ PET scanner to be well suited for clinical and research applications.

• Analytical Science and Technology
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• v.23 no.6
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• pp.531-536
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• 2010

A quantitative analytical method has been established for the measurement of inosine 5'-monophosphate dehydrogenase (IMPDH) activity in human peripheral blood mononuclear cells (PBMCs) by ion-pair reversed-phase high performance liquid chromatography equipped with ultraviolet detection (HPLC/UV). IMPDH is a ${\beta}$-nicotinamide adenine dinucleotide hydrate (NAD+)-dependent dehydrogenase in which the enzyme converts inosine 5'-monophosphate (IMP) into xanthosine 5'-monophosphate (XMP). Its activity was measured by quantifying a HPLC chromatogram corresponding to XMP produced during the incubation of lysed PBMCs with IMP as a substrate and $NAD^+$ as a coenzyme. XMP produced was detected at a wavelength of 260 nm. The mobile phase was composed of a mixture of 37 mM potassium dihydrogen phosphate containing 7 mM tetra-n-butylammonium hydrogen sulfate adjusted to pH 5.5 and methanol (85:15, v/v) with a flow rate of 1 mL/min. The calibration curve was linear ($r^2$=0.999999) in the range of $0.2-50.0\;{\mu}M$ and the limit of quantification (LOQ) was $0.2\;{\mu}M$. The intra- and inter-day precisions were between 0.88-1.47% and 0.85-5.24%, respectively. The intra- and inter-day accuracies were between 98.74-99.99% and 99.95-101.65%, respectively. IMPDH activity in 11 Korean healthy volunteers ranged from 18.29 to 36.60 nmol/h/mg protein (mean = $27.70{\pm}6.28\;nmol/h/mg$ protein).

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.196-203
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• 1999

To establish the best rice cultivating system in the aspects of environment-loving agriculture, the amounts and patterns of nitrogen leached in the paddy soil were investigated with 7 treatments; Recommendation(R), Farmer's usual practice(FUP), Straw compost+chemical fertilizers reduced(SCF), Fresh straw+recommendation(FSC), Fresh cow manure(FCM), Cow manure compost(CMC), and no fertilization as Control(C). And SCF, FCM and CMC were applied with same amounts of total nitrogen to R. The infiltrated water samples were collected in ceramic porous cups which were buried at 60cm depth from the top. Concentrations of nitrate-N in irrigated water were $1.3mg\;l^{-1}$ on rice transplanting season when nutrients began to elute from paddy soil, and $0.4mg\;l^{-1}$ after breaking off irrigation. But it was $4-6mg\;l^{-1}$ in rice growing period. The maximum concentration of nitrate-N in leachate was not more than $7mg\;l^{-1}$ during rice cultivation. The amounts of nitrogen leached in R, FUP, SCF, FSR, FCM, CMC and C were 59, 63, 25, 41, 24, 27, $17kg\;ha^{-1}y^{-1}$ respectively. Nitrogen leaching was decreased to about 30% by supplement of fresh rice straw(FSC) to R. Furthermore, it was possible to reduce to over 50% of nitrogen leaching by reducing chemical fertilizer application(CF), or by substituting of chemical fertilizers with fresh cow manure(FCM) or cow manure compost(CMC). In added organic fertilizer treatments, the amounts of infiltrated nitrogen were less $13-46kg\;ha^{-1}y^{-1}$ than that of input by irrigation. This experiment showed that nutrients leaching was minimized by substitution of chemical fertilizers with organic fertilizer or by application of straw with chemical fertilizers in rice paddy soil and rice cultivation with suitable fertilizer management can work as a purifier rather than contaminator of water.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.214-227
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• 2013

Computed tomographic scan as a screening procedures in asymptomatic individuals has seen a steady increase with the introduction of multiple-raw detector CT scanners. This report provides a brief review of the current controversy surrounding CT cancer screening, with a focus on the radiation induced cancer risks and clinical efficacy. 1. A large study of patients at high risk of lung cancer(the National Lung Screening Trial[NLST]) showed that CT screening reduced cancer deaths by 20%(1.33% in those screened compared with 1.67% in those not screened). The rate of positive screening tests was 24.2% and 96.4% of the positive screening results in the low-dose CT group were false-positive. Radiation induced lung cancer risk was estimated the most important in screening population because ERR of radiation induced lung cancer does not show the decrease with increasing age and synergistic connection between smoking and radiation risk. Therefore, the radiation risk may be on the same order of magnitude as the benefit observed in the NLST. Optimal screening strategy remain uncertain, CT lung cancer screening is not yet ready for implementation. 2. Computed tomographic colonography is as good as colonoscopy for detecting colon cancer and is almost as good as colonoscopy for detecting advanced adenomas, but significantly less sensitive and specific for smaller lesions and disadvantageous for subsequent therapeutic optical colonoscopy if polyps are detected. The average effective dose from CT colonography was estimated 8-10 $mS{\nu}$, which could be a significant dose if administered routinely within the population over many years. CT colonography should a) achieve at least 90% sensitivity and specificity in the size category from 6 and 10 mm, b) offer non-cathartic bowl preparation and c) be optimized and standardized CT parameters if it is to be used for mass screening. 3. There is little evidence that demonstrates, for whole-body scanning, the benefit outweighs the detriment. This test found large portion of patient(86~90.8%) had at least one abnormal finding, whereas only 2% were estimated to have clinically significant disease. Annual scans from ages 45 to 75 years would accrue an estimated lifetime cancer mortality risk of 1.9%. There is no group within the medical community that recommends whole-body CT. No good studies indicate the accuracy of screening CT, at this time. The benefit/risk balance for any of the commonly suggested CT screening techniques has yet to be established. These areas need further research. Therefore wild screening should be avoided.

• Journal of Aquaculture
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• v.11 no.4
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• pp.547-556
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• 1998

This study was performed to obtain the basic data on the serum constituents of several marine fish spesies commonly cultured in Korea. Blood samples taken from six species of fish were analyzed for various components of serum, total protein (TP), albumin (ALB), triglyceride (TRIG), cholesterol (CHOL), glucose (GLC), lipase (LIPA), amylase (AMYL), aspartate transaminoferase (AST), sodium (Na), potassium (K), chloride (CI) and phosphorus (PHOS). The fish used were coho salmon (Oncorhynchus kisutch), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), olive flounder (Paralichthys olivaceus), rock fish (Sebastes schlegeli), sea bass (Lateolabrax japonicus), olive flounder (Paralichthys olivaceus), parrot fish (Oplegnathus fasciatus) and jack mackerel (Trachurus jaonicus) reared at the Chungmu Experimental Fish Culture Station of KORDI when the water tempetature was ca. 16.5$^{\circ}C$. There were significant differences in TRIG, CHOL, LIPA and AMYZ among the species analyzed. TRIG concentratin were ranged 178~180mg/dl in jack mackeerel and rock fish, 126~159 mg/dl in olive flounder and sea bass, and 102~114 mg/dl in coho salmon and parrot fish, respectively. Jack mackerel showed the highest levels in CHOL (255mg/dl) and GLC(138mg/dl) among species. LIPA levels were recorded 256 U/dl in coho salmon, 41~42 U/dl in parrot fish and rock fisk, and 5~11 U/dl jack mackerel and sea bass, respectively. AMYL activity of coho salmon was measured as 2, 665 U/dl, and that of jack mackerel was 1,210 U/dl while sea bass showed 60 U/dl and parrot fish, olive flounder and rock fish had at most 5 U/dl. On the other hand, there was no significant difference in the concentration of Na and CI. Na and K were proved that they were negatively correlated in all the species. Generally, among blood components, PHOS and CHOL levels were different depending on environmental temperature of each fish species, especially in olive flounder. Rock fish and parrot fish showed high blood concentration of those components during low temperature period while olive flounder and jack mackerel reached high level during their optimal environmental temperature period. The electrolyte concentration and LIPA activity were high during low water temperature period, in general, but TP and ALB concentrations were high during optimal temperature period. The concentrations of TRIG, CHOL and GLC, those which were used as energy sourses, were different among species by season.