• The Journal of the Acoustical Society of Korea
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• v.25 no.6
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• pp.298-304
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• 2006

This paper proposes a ray-based forward modeling scheme which is suitable for the shallow water acoustic wave propagation simulations. The proposed model comprises of ray tracings for the layered media of which sound speed profiles are interpolated linearly. considerations of plane and spherical wave reflection coefficients. and calculations of the phases and the amplitudes of eigen rays. The main characteristic of the scheme is fast simulation time due to direct calculation of the broad-band time signals in the time-domain, i.e. without transformation of the frequency-domain solutions to the time si 밍 131s. Finally, we applied the model to 4-types of test environments and compared the resulting signals with those of ORCA and Ram in order to validate the proposed model.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.3996-4001
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• 2023

The High-flux Advanced Neutron Application Reactor (HANARO) produces radioisotopes (RIs) (¹³¹I, ¹⁹²Ir, etc.) through neutron irradiation on various RI production targets. Among them, ¹⁷⁷Lu and ¹⁶⁶Ho are particularly promising owing to their theranostic characteristics that facilitate simultaneous diagnosis and treatment. Prior to neutron irradiation, evaluating the nuclear heating of the RI production target is essential for ensuring the thermal-hydraulic safety of HANARO. In this study, the feasibility of producing ¹⁷⁷Lu and ¹⁶⁶Ho using irradiation holes of HANARO was investigated in terms of thermal-hydraulic safety. The nuclear heating rates of the RI production target by prompt and delayed radiation were calculated using MCNP6. The calculated nuclear heating rates were used as an input parameter in COMSOL Multiphysics to obtain the temperature distribution in an irradiation hole. The degree of temperature increase of the ¹⁷⁷Lu and ¹⁶⁶Ho production targets satisfied the safety criteria of HANARO. The nuclear heating rates and temperature distribution obtained through the in silico study are expected to provide valuable insight into the production of ¹⁷⁷Lu and ¹⁶⁶Ho using HANARO.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.3
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• pp.203-208
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• 2024

Fifteen cultured frozen abalone Haliotis discus hannai samples were purchased from supermarkets, traditional markets, online markets, and processing factories throughout Korea for the safety assessment of microbiological and chemical hazards. Sanitary-indicative (total viable bacteria, coliforms, and Escherichia coli) and pathogenic (Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Clostridium perfringens, and Enterohemorrhagic E. coli) bacterial contamination levels were assessed quantitatively or qualitatively. Additionally, heavy metal content (lead, cadmium, and total mercury) and radioactivity (¹³⁴CS+¹³⁷CS, ¹³¹I) were quantitatively assessed. The total viable bacterial count was 4.3×10² CFU/g, while coliform count was 50 CFU/g. E. coli was not detected in any of the samples (count < 10 CFU/g). All six pathogenic bacteria tested negative qualitatively. The average lead, cadmium, and total mercury contamination levels in the cultured frozen abalone were 0.100±0.057, 0.145±0.061, and 0.015±0.001 mg/kg, respectively. Moreover, none of the samples were radioactive. According to the results of this study, cultured frozen abalones distributed in all types of markets were safe from all microbiological and chemical hazards.

• Journal of radiological science and technology
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• v.38 no.3
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• pp.305-313
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• 2015

After Fukushima Daiichi nuclear disaster in 2011, study and maintenance of monitoring systems have been made at home and abroad. As concerns about radioactive contamination of water have increased in Korea, update of maintenance of managing radioactive materials in water is being made mainly by Ministry of Environment. In this study, we analysed current state of monitoring system modification in Japan, the country directly involved and neighboring country. According to the result, Japan modified the legislations first. Then Ministry of Education, Culture, Sports, Science and Technology (MEXT) provides theoretical background of radiological monitoring. And Ministry of the Environment actually watches state of water pollution in public waters and underground water. Finally related agencies like local government are monitoring current state of radioactive contamination in water environment. By region, local monitoring stations share the investigation of the whole country. Also, additional monitoring is running around nuclear facilities. After Fukushima disaster, monitoring for area near Fukushima is added. Among the reference levels, management target value of drinking water and tap water is 10 Bq/kg, and those of public water and underground water are 1 Bq/L. Measuring intervals varied from every hour to once a year, regularly or irregularly depending on the investigation. The main measuring items are air dose rate, gross ${\alpha}$, gross ${\beta}$, ${\gamma}$ radionuclide, Cs-134, Cs-137, Sr-89, Sr-90, I-131, and so on. In comparison, regulations about general public water in Korea need to be modified, while those about area near nuclear facility and drinking water are organized well. In future, therefore, domestic system would be expected to be modified with making reference to the guidelines like WHO's one. As good case of applying international guideline to domestic environment, Japanese system could be a reference when general standard of radioactivity in public water is made in Korea.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.1
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• pp.22-29
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• 2007

Purpose: Metastatic thyroid cancers with I-131 uptake have been known to show no increase of FDG uptake whereas those without I-131 uptake tend to demonstrate increased uptake on PET. In this study, we evaluated the degree of FDG uptake in primary thyroid cancers of papillary histology before surgery. Material & Methods: Forty FDG PET studies were performed on the patients who had papillary cancer proven by fine needle aspiration. The degree of FDG uptake was visually categorized as positive or negative (positive if the tumor showed discernible FDG; negative if the tumor didn't) and the peak standard uptake value (peak SUV) of the papillary thyroid cancer (PTC) were compared with the size of PTC. Results: The mean size of 26 PTC with positive FDG uptake was $1.9{\pm}1.4\;cm(0.5{\sim}5\;cm)$. In 13 PTC with negative FDG uptake, the mean size of those was $0.5{\pm}0.2\;cm\;(0.2{\sim}0.9\;cm)$. All PTC larger than 1cm ($2.5{\pm}1.4\;cm,\;1{\sim}5\;cm$) have positive FDG uptake (peak $SUV=6.4{\pm}5.7,\;1.7{\sim}22.7$). Among the micropapillary thyroid cancer (microPTC; PTC smaller than 1cm), 8 microPTC show positive FDG uptake(peak $SUV=2.9{\pm}1.3,\;1.7{\sim}5.5$), while 13 microPTC show negative finding(peak $SUV=1.3{\pm}0.2,\;1.1{\sim}1.7$). The size of microPTC with positive FDG uptake is significantly larger than that of microPTC with negative FDG uptake ($0.7{\pm}0.1\;cm$ vs $0.4{\pm}0.2\;cm$, p=0.01). Conclusion: All PTCs larger than 1cm show positive FDG uptake in our study. In other words, thyroid lesions larger than 1cm with negative FDG uptake are unlikely to be PTC. So far, only poorly differentiated thyroid cancers are known to show increased FDG uptake. Our results seem to be contradictory to what is known in the literature. Further study is needed to understand better the significance of increased FDG uptake in PTC in relation to expression of NIS and GLUT.

• Clinical and Experimental Pediatrics
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• v.45 no.4
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• pp.439-448
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• 2002

Purpose : The aim of this study is to determine and compare the effects of adjunctive therapy with different doses of recombinant human granulocyte-colony stimulating factor(rhG-CSF) on reversing sepsis-associated neonatal neutropenia, and their survival rate in a group I/II-type trial. Methods : RhG-CSF was injected subcutaneously to 10 septic-neutropenic neonates with doses of $10{\mu}g/kg$ from Oct. 1995 to Sep. 1996, and was administered to another 12 septic-neutropenic neonates with doses of $5{\mu}g/kg$ from Oct. 1996 to Sep. 1997. Neutrophilic responses and the outcomes of both groups were compared. Results : In the rhG-CSF $10{\mu}g/kg$ treated group and in the $5{\mu}g/kg$ treated group, the absolute neutrophil count(ANC) was $1,065{\pm}89$($mean{\pm}SEM$) and $1,053{\pm}131$, respectively. The only difference between the two groups was the peak ANC at 48 hours. Eight patients from the remaining nine of rhG-CSF $10{\mu}g/kg$ treated group(88.9％) and ten in $5{\mu}g/kg$ treated group(83.3％) survived the sepsis and were discharged without any problems. Conclusions : RhG-CSF can increase the neutrophil count in critically ill septic neutropenic neonats. The survival rate of both groups were up to 90％. This finding suggests that both doses of rhG-CSF may be effective in a therapeutically useful time frame to treat septic neonates with neonatal neutropenia attributable to bone marrow supression or neutrophil consumption.

• Journal of the Korean Electrochemical Society
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• v.5 no.3
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• pp.131-142
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• 2002

The Langmuir adsorption isotherms of the under-potentially deposited hydrogen (UPD H) and the over-potentially deposited hydrogen (OPD H) at the poly-Pt/0.5M $H_2SO_4$ and 0.5 M LiOH aqueous electrolyte interfaces have been studied using cyclic voltammetric and ac impedance techniques. The behavior of the phase shift $(0^{\circ}{\leq}{-\phi}{\leq}90^{\circ})$ for the optimum intermediate frequency corresponds well to that of the fractional surface coverage $(1{\geq}{\theta}{\geq}0)$ at the interfaces. The phase-shift method, i.e., the phase-shift profile $({-\phi}\;vs.\;E)$ for the optimum intermediate frequency, can be used as a new electrochemical method to determine the Langmuir adsorption isotherms $({\theta}\;vs.\;E)$ of the UPD H and the OPD H for the cathodic $H_2$ evolution reactions at the interfaces. At the poly-Pt/0.5M $H_2SO_4$ aqueous electrolyte interface, the equilibrium constant (K) and the standard free energy $({\Delta}G_{ads})$ of the OPD H are $2.1\times10^{-4}$ and 21.0kJ/mol, respectively. At the poly-Pt/0.5M LiOH aqueous electrolyte interface, K transits from 2.7(UPD H) to $6.2\times10^{-6}$ (OPD H) depending on the cathode potential (E) and vice versa. Similarly, ${\Delta}G_{ads}$ transits from -2.5kJ/mol (UPD H) to 29.7kJ/mol (OPD H) depending on I and vice versa. The transition of K and ${\Delta}G_{ads}$ is attributed to the two distinct adsorption sites of the UPD H and the OPD H on the poly-Pt surface. The UPD H and the OPD H on the poly-Pt surface are the independent processes depending on the H adsorption sites themselves rather than the sequential processes for the cathodic $H_2$ evolution reactions. The criterion of the UPD H and the OPD H is the H adsorption sites and processes rather than the $H_2$ evolution reactions and potentials. The poly-Pt wire electrode is more efficient and useful than the Pt(100) disc electrode for the cathodic $H_2$ evolution reactions in the aqueous electrolytes. The phase-shift method is well complementary to the thermodynamic method rather than conflicting.

• The Korean Journal of Nuclear Medicine
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• v.1 no.2
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• pp.1-25
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• 1967

In 20 normal cases and 39 pulmonary tuberculosis cases, regional pulmonary arterial blood flow measurements and lung perfusion scans by $^{131}I$-Macroaggregated albumin, lung inhalation scans by colloidal $^{198}Au$ and spirometries by respirometer were done at the Radiological Research Institute. The measured lung function tests were compared and the results were as the following: 1. The normal distribution of pulmonary blood flow was found to be $54.5{\pm}2.82%$ to the right lung and $45.5{\pm}2.39%$ to the left lung. The difference between the right and left pulmonary arterial blood flow was significant statistically (p<0.01). In the minimal pulmonary tuberculosis, the average distribution of pulmonary arterial blood flow was found to be $52.5{\pm}5.3%$ to the right lung and $47.5{\pm}1.0%$ to the left lung when the tuberculous lesion was in the right lung, and $56.2{\pm}4.4%$ to the right lung and $43.8{\pm}3.1%$ to the left lung when the tuberculous lesion was in the left lung. The difference of pulmonary arterial blood flow between the right and left lung was statistically not significant compared with the normal distribution. In the moderately advanced pulmonary tuberculosis, the average distripution of pulmonary arterial blood flow was found to be $26.9{\pm}13.9%$ to the right lung and $73.1{\pm}13.9%$ to the left lung when the tuberculous lesion was more severe in the right lung, and $79.6{\pm}12.8%$ to the right lung and $20.4{\pm}13.0%$ to the left lung when the tuberculous lesion was more severe in the left lung. These were found to be highly significant statistically compared with the normal distribution of pulmonary arterial blood flow (p<0.01). When both lungs were evenly involved, the average distribution of pulmonary arterial blood flow was found to be $49.5{\pm}8.01%$ to the right lung and $50.5{\pm}8.01%$ to the left lung. In the far advanced pulmonary tuberculosis, the average distribution of pulmonary arterial blood flow was found to be $18.5{\pm}11.6%$ to the right lung and $81.5{\pm}9.9%$ to the left lung when the tuberculous lesion was more severe in the right lung, and $78.2{\pm}8.9%$ to the right lung and $21.8{\pm}10.5%$ to the left lung when the tuberculous lesion was more severe in the left lung. These were found to be highly significant statistically compared with the normal distribution of pulmonary arterial blood flow (p<0.01). When both lungs were evenly involved the average distribution of pulmonary arterial blood flow was found to be $56.0{\pm}3.6%$ to the right lung and $44.0{\pm}3.2%$ to the left lung. 2. Lung perfusion scan by $^{131}I$-MAA in patients with pulmonary tuberculosis was as follows: a) In the pretreated minimal pulmonary tuberculosis, the decreased area of pulmonary arterial blood flow was corresponding to the chest roentgenogram, but the decrease of pulmonary arterial blood flow was more extensive than had been expected from the chest roentgenogram in the apparently healed minimal pulmonary tuberculosis. b) In the pretreated moderately advanced pulmonary tuberculosis, the decrease of pulmonary arterial blood flow to the diseased area was corresponding to the chest roentgenogram, but the decrease of pulmonary arterial blood flow was more extensive in the treated moderately advanced pulmonary tuberculosis as in the treated minimal pulmonary tuberculosis. c) Pulmonary arterial blood flow in the patients with far advanced pulmonary tuberculosis both before and after chemotherapy were almost similar to the chest roentgenogram. Especially the decrease of pulmonary arterial blood flow to the cavity was usually greater than had been expected from the chest roentgenogram. 3. Lung inhalation scan by colloidal $^{198}Au$ in patients with pulmonary tuberculosis was as follows: a) In the minimal pulmonary tuberculosis, lung inhalation scan showed almost similar decrease of radioactivity corresponding to the chest roentgenogram. b) In the moderately advanced pulmonary tuberculosis the decrease of radioactivity in the diseased area was partly corresponding to the chest roentgenogram in one hand and on the other hand the radioactivity was found to be normally distributed in stead of tuberculous lesion in the chest roentgenogram. c) In the far advanced pulmonary tuberculosis, lung inhalation scan showed almost similar decrease of radioactivity corresponding to the chest roentgenogram as in the minimal pulmonary tuberculosis. 4. From all these results, it was found that the characteristic finding in pulmonary tuberculosis was a decrease in pulmonary arterial blood flow to the diseased area and in general decrease of pulmonary arterial blood flow to the diseased area was more extensive than had been expected from the chest roentgenogram, especially in the treated group. Lung inhalation scan showed almost similar distribution of radioactivity corresponding to the chest roentgenogram in minimal and far advanced pulmonary tuberculosis, but there was a variability in the moderately advanced pulmonary tuberculosis. The measured values obtained from spirometry were parallel to the tuberculous lesion in chest roentgenogram.

• Journal of Embryo Transfer
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• v.16 no.2
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• pp.79-89
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• 2001

Steroid hormones control the expression of many cellular regulators, and a role thor estrogen in mouse oocytes has been well documented. The preovulatory $E_2$increment is generally accepted as the endocrine process regulating induction of in vivo oocyte maturation To address whether the activity of the T-type $Ca^{2+}$ channel is altered by 17 beta-estradiol ( $E_2$), we examined the actions of $E_2$on the calcium channel of mouse oocytes and early embryos. Oocrtes were collected from the oviduct of mice treated with pregnant mare's serum gonadotropin (PMSG) and human choronic gonadotropin (hCG). Whole cell voltage clamp technique and confocal microscopy were used to examine that $E_2$increase intracellular $Ca^{2+}$ concentration ([C $a^{2+}$]$_{i}$ ) via voltage dependent $Ca^{2+}$ channel (VDC) and estrogen receptor (FSR), and $E_2$concentration by the use of radioimmunoassay (RIA) were examined in mouse. The results obtained were as follows: The peak of $Ca^{2+}$ current induced by $E_2$increased 122% to 1.50$\pm$0.03 nA from 1.23$\pm$0.21 nA (n=15) in the presence of 5 mM extracellular $Ca^{2+}$ concentration ([C $a^{2+}$]$_{o}$ ). The increased $Ca^{2+}$ current was temporally associated with $Ca^{2+}$ transients. The intracellular $Ca^{2+}$ level increased 207%~30 s following the addition of 1${\mu}{\textrm}{m}$ $E_2$(relative fluorescence intensity: 836.4$\pm$131.2 for control, n=10, 1736.4$\pm$192.0 in the presence of $E_2$, n=10). $E_2$increased amplitude of $Ca^{2+}$ current and [C $a^{2+}$]$_{i}$ . $E_2$-induced $Ca^{2+}$ current and $E_2$concentration in blood were showed difference on the stage of embryo. These results suggest that $E_2$modulate $Ca^{2+}$ channel to increase $Ca^{2+}$ influx.$Ca^{2+}$ influx.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.294-300
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• 2009

Purpose: The purpose of this study was to evaluate if short-term serum thyroglobulin (Tg) elevation after radioiodine administration can predict successful radioiodine remnant ablation (RRA) and whether comparable RRA effectiveness is exhibited between a group administered with recombinant human thyrotropin (rhTSH) and a group experiencing thyroid hormone withdrawal (THW), in preparation for RRA. Materials and Methods: A retrospective chart review was performed on 39 patients in the rhTSH group and 46 patients in the THW group. They were treated for differentiated thyroid carcinoma by total or near total thyroidectomy, and referred for RRA between 2003 and 2006 (the rhTSH group) and between January and June of 2006 (the THW group). They were assessed for serum Tg levels just before I-131 administration (TgD0), reassessed 9 days later (TgD9), and again 6-12 months later. Results: RRA was successful in 64 (37 from the THW group and 27 from the rhTSH group) of the total 85 patients. The success rates of RRA had no statistically significant differences between the two groups. In both groups, TgD9/TgD0 values were significantly higher in the RRA success group (the rhTSH group; P = 0.03, the THW group; P = 0.04). By combining cutoff values of TgD0 and TgD9/TgD0, the successful RRA value was determined to be 96.7% (29/30) with TgD0$\leq$5.28 ng/mL and TgD9/TgD0>4.37 in both groups (the rhTSH group; 100% (16/16), the THW group; 92.9% (13/14)). Using logistic multivariate analysis, only TgD0 was independently associated with successful RRA. Conclusion: We may predict successful ablation by evaluating short-term serum Tg elevation after I-131 administration for RRA, in both rhTSH and THW patients.