• Progress in Medical Physics
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• v.19 no.2
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• pp.102-112
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• 2008

We developed a high-resolution micro-CT system based on rotational gantry and flat-panel detector for live mouse imaging. This system is composed primarily of an x-ray source with micro-focal spot size, a CMOS (complementary metal oxide semiconductor) flat panel detector coupled with Csl (TI) (thallium-doped cesium iodide) scintillator, a linearly moving couch, a rotational gantry coupled with positioning encoder, and a parallel processing system for image data. This system was designed to be of the gantry-rotation type which has several advantages in obtaining CT images of live mice, namely, the relative ease of minimizing the motion artifact of the mice and the capability of administering respiratory anesthesia during scanning. We evaluated the spatial resolution, image contrast, and uniformity of the CT system using CT phantoms. As the results, the spatial resolution of the system was approximately the 11.3 cycles/mm at 10% of the MTF curve, and the radiation dose to the mice was 81.5 mGy. The minimal resolving contrast was found to be less than 46 CT numbers on low-contrast phantom imaging test. We found that the image non-uniformity was approximately 70 CT numbers at a voxel size of ${\sim}55{\times}55{\times}X100\;{\mu}^3$. We present the image test results of the skull and lung, and body of the live mice.

• The Korean Journal of Nuclear Medicine
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• v.34 no.3
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• pp.252-259
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• 2000

Purpose: The purpose of this study was to compare the radiation adaptive response (RAR) in peripheral lymphocytes (PL) of patients induced by Tc-99m MDP and Tc-99m DTPA scintigraphies. Materials and Methods: Lymphocytes from 45 patients (25 males, 20 females, mean age $44{\pm}18$ years) were collected before and after scintigraphies using 740 MBq Tc-99m MDP (n=22) or Tc-99m DTPA (n=23). Lymphocytes from 20 controls (12 males, 8 females, mean age $43{\pm}7$ years) were also collected. They were exposed to challenge dose of 2 Gy ${\gamma}-rays$ using a Cs-137 cell irradiator Number of ring-form (R) and dicentric (D) chromosomes was counted under the light microscope. From them a representative score, Ydr, was calculated as Ydr=(D+R)/cells. Adaptation index (AI) was defined as difference of Ydr between unconditioned and conditioned lymphocytes. Ydr was also measured after an administration of cycloheximide (CHM), a protein synthesis inhibitor, before challenge dose. Results: RAR was induced in both groups of patients. CHM abolished the adaptive response in both groups. AI of Tc-99m MDP group was significantly higher than that of Tc-99m BTPA group. Conclusion: Tc-99m MDP induced RAR was more prominent than those induced by Tc-99m DTPA.

• Korean Journal of Ichthyology
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• v.12 no.4
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• pp.236-243
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• 2000

The purpose of present the study was to describe the spawning behavior and early life history of the grass puffer, Takifugu niphobles. The grass puffer was caught at the spawning ground on the coast Dolsan, Korea from May to the 1998. Artificial fertilization was carried out to get fertilied eggs. Spawning season was from the end of May to the beginning of July on the coast of the Dolsan, Korea. Form 2~6 days before the spring tide the aduct males and females began to aggregate in the shore water, and they spawned in the upper part of intertidal zone exposed to air among pebble stone. The fertilized eggs were demersal, transparent and spherical in shape, and its diameter were 0.87~0.95 mm with several oil globules of 0.0014~0.0540 mm. Hatching began about 146 hours after fertilization under water temperature $21.2{\sim}22.3^{\circ}C$. The newly-hatched larva was 2.02~2.24 mm in total length (TL, mean: 2.14 mm), with 22~24(8~9+14~15) myotomes, and mouth and anus was not yet open. In 3 days after hatching it was measured 2.64~2.93 mm in TL (mean: 2.76 mm), and yolk sac was completely absorbed and transformed to postlarval stage. In 15 days after hatching it was measured 4.43~4.82mm in TL (mean: 4.59mm), and the caudal notochord flexion started. The larvae reached the juvenile stage in 28 days after hatching and attained 7.55~7.65mm in TL (mean: 7.60mm), and all fin-rays were formed.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.179-189
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• 2001

The determination of trace concentration of U, Th and Pb was carried out for chemical dating of zircon and monazite by electron microprobe. Detection limit and error range should be considered to measure characteristic X-rays of M-line from those minerals, which are low in the ionization of atom and low peak intensity in the spectrum. The element of U, Th and Pb were simultaneously measured with 3 spectrometers equipped with PET crystal to reduce a total counting time and error due to drift of instrumental operating condition. Detection limit could be improved from increase of the peak/background ratio through adjusting pulse height analyzer about 1000 mv baseline. Under permissible maximum analytical conditions, theoretical detection limit of U, Th and Pb is down to 30 ppm (99% confidence level). The analytical result was maintained at a relative error $\pm$10% ($2{\sigma}$) in 800 ppm Pb, $\pm$5% ($2{\sigma}$) in 2330 ppm U and $\pm$10% ($2{\sigma}$) in dating from a single measurement of zircon at 15 keV and 100 nA. However, for the precise dating of zircon and monazite, if it is considered a 3 $\mu\textrm{m}$ spatial resolution, <100 ppm ($3{\sigma}$) detection limit and <$\pm$10% ($2{\sigma}$) relative error, optimum analytical conditions are given as 15~20 keV accelerating voltage, 100~200 nA beam current and 300~1200 sec total counting time. To reduce material damage by high current, there is need to be up to 3~5 $\mu\textrm{m}$ of electron beam diameter, or to use arithmetic average of multiple measuring at a shorter counting time. A younger or relatively low concentration rocks can be dated chemically by lower detection limit and improved precision resulted from increase of current and measuring time.

• Journal of radiological science and technology
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• v.8 no.2
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• pp.47-63
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• 1985

This paper was aimed to study the effects of Cobalt-60 gamma ray irradiation on Albino rat blood cells and the activity of enzymes were measured using blood cell auto analyzer (Cell-Dyn 900) and enzyme autoanalyzer (Gilford 3500) respectively. Cobalt-60 gamma rays those are grouped into 200R, 400R, 600R, 800R, 1,000R, 1,200R, 1,300R, 1,400R, 1,500R and 1,600R to the rats of male and female and measured the numeral varieties of blood corpuscles of the rats and the active varieties of enzyme of acid, alkaline phosphatase (ACP, ALP), lactic acid dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase. (GPT) those came out after 1, 3, 5 or 7 days. The results are summarized as follows: 1. In both case of male and female, the numeral varieties of the erythrocytes, in the 200R group of irradiation showed the minimum value in the 3 days group and a tendency of increase in the 5 and 7 days groups, while the numeral varieties of the leucocytes in every groups of irradiation showed a tendency of a rapid decrease after a day. The numeral varieties of the blood platelet in both case of male and female didn't show generally any great change in a day and 3 days groups, but showed a rapid decreasing appearance after the 5 days. 2. In both case of male and female, the activities of ACP were on the decrease gradually after 3 days of the irradiation and the activities of ALP were on the decrease after 5 days. Similarly in both case of mate and female, the activities of LDH showed the decrease after 3 and 5 days, and the phenomenous of GOT showed an appearance of increase in a day, but decreased after 3 days. As for the GPT activities couldn't find any great change in the male rats in comparison with the control groups, but in the female rats a tendency of the increase in 600R, 800R, 1,000R groups after 3 days. 3. In the case of the irradiation of high quantity of ray more than 1,200R, all rats died after 4 days, and by the irradiation of 1,600R all rats died after 3 days, and it showed the sensitive response of a living body to the irradiation of high quantity.

• Journal of radiological science and technology
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• v.31 no.3
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• pp.223-228
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• 2008

The most critical point in the medical use of radiation is to minimize the patient's entrance dose while maintaining the diagnostic function. Low-energy photons (long wave X-ray) among diagnostic X-rays are unnecessary because they are mostly absorbed and contribute the increase of patient's entrance dose. The most effective method to eliminate the low-energy photons is to use the filtering plate. The experiments were performed by observing the image quality. The skin entrance dose was 0.3 mmCu (copper) filter. A total of 80 images were prepared as two sets of 40 cuts. In the first set (of 40 cuts), 20 cuts were prepared for the non-filter set and another 20 cuts for the Cu filter of signal + noise image set. In the second set of 40 cuts, 20 cuts were prepared for the non-filter set and another 20 cuts for the Cu filter of non-signal image (noisy image) with random location of diameter 4 mm and 3 mm thickness of acryl disc for ROC signal at the chest phantom. P(S/s) and P(S/n) were calculated and the ROC curve was described in terms of sensitivity and specificity. Accuracy were evaluated after reading by five radiologists. The number of optically observable lesions was counted through ANSI chest phantom and contrast-detail phantom by recommendation of AAPM when non-filter or Cu filter was used, and the skin entrance dose was also measured for both conditions. As the result of the study, when the Cu filter was applied, favorable outcomes were observed on, the ROC Curve was located on the upper left area, sensitivity, accuracy and the number of CD phantom lesions were reasonable. Furthermore, if skin entrance dose was reduced, the use of additional filtration may be required to be considered in many other cases.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.180-195
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• 2011

A balanced trophic model for Sinjido marine ecosystem was constructed using ECOPATH model and data obtained 1994 in the region. The model integrates available information on biomass and food spectrum, and analyses ecosystem properties, dynamics of the main species populations and the key trophic pathways of the system, and then compares these results with those of other marine environments. The model comprises 17 groups of benthic algae, phytoplankton, zooplankton, gastropoda, polychaeta, bivalvia, echinodermata, crustacean, cephalopoda, goby, flatfish, rays and skates, croaker, blenny, conger, flatheads, and detritus. The model shows trophic levels of 1.0~4.0 from primary producers and detritus to top predator as flathead group. The model estimates total biomass(B) of 0.1 $kgWW/m^2$, total net primary production(PP) of 1.6 $kgWW/m^2/yr$, total system throughput(TST) of 3.4 $kgWW/m^2/yr$ and TST's components of consumption 7%, exports 43%, respiratory flows 4% and flows into detritus 46%. The model also calculates PP/TR of 0.012, PP/B of 0.015, omnivory index(OI) of 0.12, Fin's cycling index(FCI) of 0.7%, Fin's mean path length(MPL) of2.11, ascendancy(A) of 4.1 $kgWW/m^2/yr$ bits, development capacity(C) of 8.2 $kgWW/m^2/yr$ bits and A/C of 51%. In particular this study focuses the analysis of mixed trophic impacts and describes the indirect impact of a groupb upon another through mediating one based on 4 types. A large proportion of total export in TST means higher exchange rate in the study region than in semi enclosed basins, which seems by strong tidal currents along the channels between islands, called Sinjido, Choyakdo and Saengildo. Among ecosystem theory and cycling indices, B, TST, PP/TR, FCI, MPL and OI are shown low, indicating the system is not fully mature according to Odum's theory. Additionally, high A/C reveals the maximum capacity of the region is small. To sum up, the study region has high exports of trophic flow and low capacity to develop, and reaches a development stage in the moment. This is a pilot research applied to the Sinjido in terms of trophic flow and food web system such that it may be helpful for comparison and management of the ecosystem in the future.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.9-16
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• 2018

Hangover after drinking is different from person to person symptoms and degree, but usually thirst, fatigue, headache, general boredom, gastrointestinal disorder, vomiting, diarrhea, deficiency of vitamin appears. This hanging phenomenon is caused by the action of precursors such as ethyl acetate and acetaldehyde, which are the by products of fermentation contained in alcohol and alcohol accumulated in hepatocytes and body. In order to solve the hangover phenomenon, the same Origin as polysaccharide Polydeoxyribonucleotide, which is a nucleic acid-sugar-phosphate complex, which is a semen or testicular extract in salmon extract, and a water soluble salmon extract powder having the same structure and lower price than Polydeoxyribonucleotide And D-Glucuronic acid and N-Acetyl glucosamine. It has excellent biocompatibility, viscoelasticity and moisturizing power. It has effect on reduction of body water loss and skin moisture content in hangover phenomenon. It is antioxidant and skin moisturizing effect Hyaluronic acid was irradiated with gamma rays, and the composition was prepared by using the salmon extract powder and the main raw material. The ethanol degradation, the acetaldehyde reduction amount, the blood acetaldehyde concentration and the acetic acid concentration were measured to evaluate the alcoholysis effect, Skin moisture evaporation rate To examine the evaluation unit water content of the skin was improved determine whether the antioxidant and provide skin moisturizing effect. The addition of ethanol extracts of salmon extracts showed a decrease of 5 to 7 times compared with no addition, and a decrease of 3 to 5 times of acetaldehyde. In addition, the change of acetaldehyde concentration and acetic acid concentration in blood showed a rapid decrease compared to the no - added control group. In addition, when the raw material of hyaluronic acid was used, skin moisture content was high and skin moisture evaporation amount was decreased. Therefore, hyaluronic acid, which is a polysaccharide polymer, has excellent viscoelasticity and moisturizing ability, It is considered to provide antioxidant and skin moisturizing effect. Therefore, it can be said that the composition containing salmon extract powder and hyaluronic acid as a main ingredient is effective for the hangover phenomenon which occurs after drinking.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.8 no.2
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• pp.150-156
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• 2005

Purpose: We divided the children diagnosed with intususception into three different age groups and compared the clinical symptoms and treatment outcomes in order to analysis diagnosis and treatment of Intusussception. Methods: A retrospective chart review was established of 159 patients diagnosed with intussuception who had been admitted to Department of Pediatrics and General Surgery, Bundang CHA hospital from January, 2000 to May, 2004. We divided the patients into three groups, according to their age. Those who were under five months of age (group I; 21 patients), those between 5~11 months of age (group II; 61 patients), and those older than 11 months of age (group III; 77 patients). Then we compared the age, sex, seasonal distribution of occurrence, the cause, the clinical features, radiologic review, the type of intusussception, surgical methods, recurrence rate and treatment outcomes, among these three groups. Results: On comparing the clinical symptoms and signs among the three groups, the most common major clinical symptom and sign was irritabiltity in all three groups. Vomiting with irritability was statistically more common in group I (p<0.05) and bloody stool was most frequent in group III. The average time taken until a diagnosis was made after the symptom onset was, 21 hours in group I, 20 hours in group II and 22 hours in group III. Which showed no significant difference. But there was a higher rate of delayed diagnosis in group I, which took over 48 hours until the diagnosis was made (group I; 23.8%, group II; 4.9%, group III; 7.8%). Simple abdominal X-rays showed more frequent instances of intestinal obstruction in group I (p<0.05). The primary treatment done was barium enema which showed a failure rate of 52.4% in group I, 26.2% in group II and 14.3% in group III. Showing the highest failure rate in group I. Conclusion: The youngest group had vague symptoms which lead to delayed diagnosis and more frequent surgical procedures. As so, we advocate the importance of further evaluation and close observation, considering intussusception in children with symptoms of irritability and vomiting, especially in the early infant group.

• Pediatric Infection and Vaccine
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• v.15 no.1
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• pp.52-58
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• 2008

Purpose : Whole blood interferon-$\gamma$ assay was developed and many studies showed its usefulness in diagnosing tuberculosis (TB) including latent tuberculosis infection (LTBI). However, assessment in children has been limited. This study was undertaken to evaluate the usefulness of QuantiFERON-TB Gold for the diagnosis of LTBI in children exposed to pulmonary TB. Methods : Children who visited Seoul National University Bundang Hospital with a history of TB exposure were enrolled from January 2006 to December 2007. They were evaluated with chest x-rays, tuberculin skin test (TST) and QuantiFERON-TB Gold test. TST was retested 3 months later for those with initial negative reactivity. Definition of LTBI was made on the basis of the TST reactivity. Results : Among the 103 children with a history of TB exposure, 49 children were tested with chest x-ray, TST, and QuantiFERON-TB Gold. Twenty-two were males. Median age was 7.5 years (range; 3 months to 14.7 years). According to TST reactivity, LTBI was in 8 (19%), no infection was in 21 (50%), possible LTBI was in 13 (31%). QuantiFERON-TB Gold test was positive in 5 of the 49 subjects (10%); 3 of the 13 subjects (23.1%) in unknown status, 1 of the 8 subjects (13%) in LTBI, and 1 of the 21 subjects (5%) without infection. The agreement between the QuantiFERON-TB Gold and the TST was poor (${\kappa}=0.101$). Conclusion : QuantiFERON-TB Gold showed poor sensitivity for the diagnosis of LTBI in children with exposure to TB. QuantiFERON-TB Gold alone does not seem to be useful in the diagnosis of LTBI in children.