• Applied Biological Chemistry
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• v.25 no.3
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• pp.155-160
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• 1982

Claviceps purpurea PRL 1980 produces a fluorescent reddish brown pigment in the alkaloid production medium. When D,L-tryptophan $[side\;chain-3-^{14}C]$ was administered into the production medium, the radioactive pigment and 5-hydroxytryphan were isolated from the cultures. Conversion of tryptophan to 5-hydroxytryptophan in vivo was shown by an isotopic trapping procedure. 5-hydroxytryptophan isolated from the cultures contained appreciable radioactivity and was recrystallized to constant specific radioactivity. The injection of the $^{14}C-labelled$ 5-hydroxytryptophan showed an incorporation of radioactivity into brown pigment significantly higher than that of tryptophan. The brown pigment produced by Claviceps purpurea PRL 1980 seems to be derived from tryptophan through 5-hyrdroxytryptophan.

• YAKHAK HOEJI
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• v.39 no.6
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• pp.577-584
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• 1995

On the combination of antacid, the pharmacokinetics and gastric adhesion of [$^{14}c$]aceglutamide aluminium complex([$^{14}C$]AGA) were examined in rats. Specially, this study was focused on the drug interaction that the co-administration of antacid may affect the oral absorption and gastric adhesion of aceglutamide aluminium complex(AGA). In the study of the oral co-administration of [$^{14}C$] AGA and antacid(aluminium hydroxide and magnesium hydroxide(AM)), the radioactivity of plasma and urinary recovery was lower than that of [$^{14}C$]AGA alone administered group. However, the cumulative recovery of radioactivity in feces was increased significantly. The comparative bioavailability of [$^{14}C$] AGA from the plasma concentration-time curve and urinary recovery was about 60%. In vitro, the effect of antacid on the gastric adhesion of AGA was not significatly different between AGA and AGA/antacid treatment. And it accorded well with the result of in vivo experiment. In conclusion, on the combination of antacid, the oral absorption of AGA was decreased by the gastric adhesion was not affected in respect of drug interaction.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.439-455
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• 2020

Numerical model was developed that simulates radionuclide (3H and 14C) transport modeling at the 2nd phase facility at the Wolsong LILW Disposal Center. Four scenarios were simulated with different assumptions about the integrity of the components of the barrier system. For the design case, the multi-barrier system was shown to be effective in diverting infiltration water around the vaults containing radioactive waste. Nevertheless, the volatile radionuclide 14C migrates outside the containment system and through the unsaturated zone, driven by gas diffusion. 3H is largely contained within the vaults where it decays, with small amounts being flushed out in the liquid state. Various scenarios were examined in which the integrity of the cover barrier system or that of the concrete were compromised. In the absence of any engineered barriers, 3H is washed out to the water table within the first 20 years. The release of 14C by gas diffusion is suppressed if percolation fluxes through the facility are high after a cover failure. However, the high fluxes lead to advective transport of 14C dissolved in the liquid state. The concrete container is an effective barrier, with approximately the same effectiveness as the cover.

• Ocean and Polar Research
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• v.44 no.1
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• pp.99-111
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• 2022

Together with the development of measurement techniques, radiocarbon (¹⁴C) has been increasingly used as a key tool to investigate carbon cycling and associated biogeochemistry in the ocean. In this paper, the current status of radiocarbon studies in the East Sea (Japan Sea) is reviewed. Previously, spatiotemporal distribution and change of the water masses in the East Sea from 1979 to 1999 were investigated by using the ¹⁴C in the dissolved inorganic carbon (DIC). Researches on sinking particulate organic carbon (POC) revealed that POC in the deep ocean has more complex and heterogeneous origins than we expected. In particular, since 2011, Korean researchers have been collecting sinking particle samples for more than 10 years, so it is expected that ¹⁴C of POC will provide important information to understand carbon cycling in relation to climate change. Although the quantity of ¹⁴C data published in the East Sea is still limited, the importance and the future direction of using ¹⁴C to understand the biogeochemical mechanisms of carbon cycling and its role as a carbon reservoir in the East Sea are detailed herein.

• Nuclear Engineering and Technology
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• v.56 no.8
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• pp.2906-2915
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• 2024

Radiocarbon (¹⁴C), with a radioactive half-life of approximately 5730 years, poses a long-term environmental contamination risk when released into the atmosphere. The quantification analysis of its release estimates plant-specific generation rates based on factors such as plant power, core neutron flux distribution, and the volume of water exposed to this flux. Utilizing the improved estimation method, the ¹⁴C production rate for several Korean Pressurized Water Reactors (PWRs) was calculated. Also, improvements in measurement methods through sampling have also been made. These enhancements include the verification of the absorption method versus the mixing method. The results of this study indicate that plant-specific ¹⁴C production rates range from 0.213 to 0.317 TBq/yr, which are comparable to the global range observed in PWRs. Furthermore, the study evaluated a quenching correction curve for a liquid scintillation counter using two quenching correction methods: the external standard method and the internal standard method. The accuracy of these methods with 72 samples was validated with an average relative error within ±2.5%. The relative error of the mixing method, when compared to the direct absorption method, was found to be within ±20%. This finding underscores the validity of the improved measurement technique.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.229-234
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• 1999

The effects of linoleic acid(LA, 18 : 2) and/or bovine serum albumin(BSA) on the lipid metabolism in human hepatoma cell line HepG2 cells were evaluated. HepG2 cells were cultured in basal Dulbecco's modified Eagle's(DME) medium(Basal medium), DME medium containing 0.2 mM LA(LA medium), or DME medium containing both 0.2 mM LA and 0.2-1.0% BSA(LA+BSA medium). $[^{14}C]Acetate(0.3\;{\mu}Ci/ml\;medium)$ was added as a radioactive lipid precursor and the cells were incubated for 6 hours. An addition of LA to basal medium resulted in a decrease in the incorporation of $[^{14}C]acetate$ into total cholesterol fraction. In contrast, an addition of BSA to LA-containing medium tended to increase the incorporation of $[^{14}C]acetate$ into total cholesterol. The alteration of cholesterol metabolism in HepG2 cells incubated in LA+BSA medium was attributed by an increase in the incorporation of $[^{14}C]acetate$ into free cholesterol, but not cholesteryl ester fraction. In addition, the secretion of cholesterol was increased by LA+BSA medium, suggesting that BSA stimulates cholesterol secretion. No significant change in the incorporation of $[^{14}C]acetate$ into cellular total lipids was observed among the experimental groups. However, an increased incorporation of $[^{14}C]-labelled$ fatty acid into cellular triacylglycerol and decreased incorporation into phospholipid were observed in cells incubated with LA+BSA medium as compared to those of LA medium. The secretions of $[^{14}C]-labelled$ triacylglycerol, phospholipid, and free fatty acid were also stimulated in HepG2 cells incubated with LA+BSA medium. In conclusion, the present study suggests that in human hepatocytes, LA and BSA influence lipid metabolism, and BSA enhances the secretion of lipids.

• The Korean Journal of Zoology
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• v.29 no.2
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• pp.79-85
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• 1986

The purpose of the present experiment is to make certain the exsistence of cAMP phosphodiesterase (PDE) in mouse oocytes and confirm its possible role on meiotic resumption. The results showed two types of cAMP in the oocytes with different Michaelis constants (Km) with specific maximum (Vmax); The Km and Vmax of one of two types of PDE were estimated at $0.14 \\pm 0.01 \\muM$ and $0.42 \\pm 0.07$ fmol cAMP hydrolyzed/oocyte/minute, and the other at $14.5 \\pm 2.0 \\muM$ and $2.2 \\pm 0.5$ fmol cAMP hydrolyzed/oocyte/minute. cAMP hydrolysis by PDE was reversibly inhibited in vitro by presence of theophylline or isobutyl-methyl-xanthine (IBMX), which is well known as an inhibitor of oocyte maturation. Consequently, it can be assumed that maturation of oocyte is affected by the high level of intracellular cAMP, and its level is well maintained by presence of PDE inhibitor, such as theophylline and IBMX.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.9
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• pp.1285-1289
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• 2000

This study investigated the lipogenesis capacity of hepatocytes and lipolysis rate of adipocytes of broilers as affected by different fatty acids (trial one) and different linoleic acid (C18:2) levels (trial two). Twenty 6-wk old broilers were used; their hepatocytes and adipocytes were isolated for the in vitro study. In trial one, four treatments were tested. The control group in which no fatty acid was added, and the test groups to which were added $300{\mu}M$ of C16:0, C18:1 and C18:2, respectively. For trial two, different levels (0, $300{\mu}M$ and 1 mM) of C18:2 combined to fatty acid-free bovine serum albumin (BSA) were added to the medium. According to results of trial one, added fatty acids significantly reduced the incorporation by hepatocytes of [U,$^{14}C$]glucose into total lipid (p<0.05); the lipogenesis capacity in C18:2 group was the lowest. Although a similar pattern was found with [l,$^{14}C$]acetate, the groups only slightly differed in terms of lipogenesis capacity (p=0.11). In addition, the C18:2 group had a significantly (p<0.05) greater lipolysis rate than the C16:0 and control groups. Results of trial two indicated that C18:2 significantly (p<0.05) reduced lipogenesis capacity both for [U,$^{14}C$]glucose and [l,$^{14}C$]acetate, and markedly stimulated the lipolysis rate (p<0.05), displaying a dose response. Results presented herein demonstrate that C18:2 can reduce lipogenesis capacity and stimulate the lipolysis rate in broilers.

• Restorative Dentistry and Endodontics
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• v.5 no.1
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• pp.29-34
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• 1979

The purpose of this study was to measure thermal expansions of dental investments, Biovest(Casting Investment. Dentsply International INC, U.S.A.), Multi-Best (Use for all dental chrome-cobalt alloys, The Ransom & Randolph Co. U.S.A.), Kerr(Inlay Investment. Sybron Kerr, U.S.A.), O. K. (Inlay Investment. Shofu Dental MFG, Co. Japan), Whip-Mix (Cristobalite Inlay Investment. Whip-Mix Corporation. U.S.A.). Thermal expansion of specimens(5mm in diameter and 50mm in length) was measured by a dilatometer at the temperature range from $20^{\circ}C$ to $700^{\circ}C$ by comparing expansion between standardized quartz and experimental specimens with heating rate about $300^{\circ}C$/hr. The following results were obtained. 1. The coefficient of thermal expansion of Biovest was $15{\times}10^{-6}/^{\circ}C$ in the water powder ratio 18/100 and $14{\times}10^{-6}/^{\circ}C$ in the water powder ratio 28/100. Those of Multi-Best were $9{\times}10^{-6}/^{\circ}C$ in the water powder ratio 14/100 and $7{\times}10^{-6}/^{\circ}C$ in the water powder ratio 24/100. 2. The coefficient of thermal expansion of Kerr were $17{\times}10^{-6}/^{\circ}C$ in the water powder ratio 38/100 and $14{\times}10^{-6}/^{\circ}c$ in the water powder ratio 48/100. Those of O. K. were $9{\times}10^{-6}/^{\circ}C$ in the water powder ratio 33/100 and $7{\times}10^{-6}/^{\circ}C$ in the water powder ratio 43/100 3. The coefficient of thermal expansion of Whip-Mix were $14{\times}10^{-6}/^{\circ}C$ in the water powder ritio 40/100 and $12{\times}10^{-6}/^{\circ}c$ Fein the water powder ratio 50/100. Those of Hi-Heat were $11{\times}10^{-6}/^{\circ}c$ in the water powder ratio 28/100 and $10{\times}10^{-6}/^{\circ}c$ in the water powder ratio 38/100.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.125-129
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• 1984

Emergence and early growth of Eleocharis kuroguwai, Potamogeton distinctus, and Sagittaria pygmaea were examined at 10, 14, 18, 22, 26, and $30^{\circ}C$ of soil temperatures using soil temperature gradient bath. Eleocharis kuroguwai emerged at $14^{\circ}C$ or higher temperature and % emergence was increased as soil temperature increased up to $26^{\circ}C$ but decreased at $30^{\circ}C$. Percentage of emergence in Potamogeton distinctus was very low at $10^{\circ}C$ but most of them were emerged at $14^{\circ}C$ or above. Emergence rate was faster as soil temperature increased. Percentage of emergence in Sagittaria pygmaea was increased until 10 days after planting as soil temperature increased but final percentage of emergence was 100% at all temperature. Number of days required for 80% emergence was shortened as soil temperature increased and Eleocharis kuroguwai and Potamogenton distinctus required longer duration to emerge compared to Sagittaria pygmaea. Eleocharis kuroguwai and Potamogeton distinctus required higher accumulated soil temperature for emergence compared to Sagittaria pygmaea. Optimum soil temperature for early growth after emergence of Eleocharis kuroguwai, Potamogeton distinctus, and Sagittaria pygmaea were 26, 18-22, and 18-$26^{\circ}C$, respectively.