• Journal of Pharmaceutical Investigation
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• v.25 no.2
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• pp.145-152
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• 1995

The superoxide dismutase (SOD) mimetic activity of copper complex of 3,5-disopropylsalicylic acid (Cu(II)-DIPS) was tested and compared to those of human recombinant SOD (hrSOD) and its conjugate form with polyethyleneglycol (PEG) using fer- ricytochrome c reduction assay. Stability constant of Cu(II)-DIPS was measured po- tentiometrically using SCOGS2 program. In the presence of 10 g/L albumin, Cu(II)-DIPS lost most of its SOD mimetic activity. HrSOD was modified with polyethylene glycol (PEG) of M.W. 5000. These conjugates have markedly prolonged plasma half-lives of enzymatic activity (15.5 hr) compared to native hrSOD (5 min). In summary, efficient SOD mimetics should be stable enough not to dissociate in blood by serum protein. HrSOD could have longer half-life by conjugation with inert PEG for sustained SOD effect.

• Journal of Pharmaceutical Investigation
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• v.25 no.4
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• pp.313-322
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• 1995

The covalent conjugation of human recombinant superoxide dismutase (hrSOD) with trichloros-triazine activated polyethylene glycol (PEG) 5000 formed soluble conjugates with molecular weight of 92KD, which retained $90{\sim}98%$ of original activity with a markedly prolonged plasma half-life of enzyme activity. The effect of hrSOD-PEG conjugates on acetaminophen (ACP)-induced hepatotoxicity was tested in male rats which were pretreated with 3-methylcholanthrene. HrSOD-PEG conjugates inhibited the hepatotoxicity produced by ACP, on the other hand, native hrSOD had no protective effect. The above results indicated that oxygen radicals might participate in the mechanism of the ACP-induced hepatotoxicity and that polymer conjugated-protein drugs with prolonged half-lives could be employed as an effective therapeutic agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.3
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• pp.229-234
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• 1985

The effect of packaging on the quality of dried anchovy was investigated, when packed with various materials and stored at different conditions. In cases of nitrogen gas substitution or addition of antioxidant, the reaction rates of lipid oxidation, the loss of available lysine and browning of the samples sealed in aluminum laminated film bag were lower than those packed in kraft paper or polyethylene film bag while the samples without gas substitution did not reveal any great differences in the rate of the reactions. The shelf-lives of the samples computed as a function of lipid oxidation were 90, 98 and 137 days at the storage of $35^{\circ}C$ for the packages of kraft paper, polyethylene and aluminum film respectively. And those at $55^{\circ}C$ storage for the same samples were 47, 51 and 77 days. The half-lives of available lysine loss were 227, 209 and 312 days at $35^{\circ}C$: 83, 83 and 147 days at $55^{\circ}C$ for the samples respectively. And the shelf-lives determined as a function of browning reaction were 26, 27 and 49 days at $55^{\circ}C$. The predicted shelf-lives at $25^{\circ}C$ as a function of lipid oxidation were 130, 140, and 189 days for kraft paper, polyethylene and aluminum laminated film packaging: 207, 229 and 246 days for the browning reaction, and 363, 339 and 415 days for the loss of available lysine. The results suggest that the protective effect of packaging on the reactions of lipid oxidation and browning could not be aided unless the air was expelled or replaced to inert gas.

• Environmental Analysis Health and Toxicology
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• v.22 no.2 s.57
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• pp.177-184
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• 2007

Gaseous organochlorine pesticides (OCPs : heptachlor epoxide, p, p'-DDE, ${\gamma}-HCH,\;{\alpha}-chlordane,\;{\gamma}-chlordane$ and trans-nonachlor) concentration was measured using PUF high volume sampler from June, 2000 to June, 2002 in the semi-rural atmosphere. The OCPs concentration in atmosphere, which is estimated by the slope (m) of Clausius-Clapeyron equation and phase-transition energy $({\Delta}H)$, was influenced by revolatilization from environmental matrix (soil, water and tree leaves) and a long range transportation of air mass. But the former affected OCPs concentration more than the latter. The degradation rate constants (k) of OCPs calculated using multiple regression analysis and revised standard temperature method were in good agreement each other. The value of k of ${\gamma}-HCH$ was very low as -0.0007, but the range of k of other components were $-0.00l8{\sim}-0.0038$. The half-life $({\tau})$ which was calculated by k of ${\gamma}-HCH$ was 2.6 years-the longest one, but that of heptachlor epoxide was in 0.5 year-the shortest one. $({\tau})\;of\;{\alpha}-chlordane,\;{\gamma}-chlordane$ and trans-nonachlor in technical chlordane was 1.0, 1.1 and 0.7 year respectively.

• Radioisotope journal
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• v.21 no.3
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• pp.46-60
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• 2006

In recent years the progress of nuclear medicine advanced dramatically in imaging and targeted radionuclide therapy is able to open op exciting perspectives as standard diagnostic and therapeutic modalities, complementing conventional modalities. Positron emission tomography/computed tomography (PET/CT) technology with FDG has been developed clinically in less than 10 years as a routine standard in oncological imaging, including a number of other fluorinated radiopharmaceuticals being evaluated for their ability to complement FDG. However, the limitation of FDG-PET such as non-specific uptake and its short half-life is not compatible with the time necessary for optimal tumour targeting. Therefore, a development of innovative positron-emitting radionuclides with half-lives longer than 10 h is needed. For therapeutic applications, the injection of higher activities is required to reach efficient adsorbed doses in radioresistant solid tumours, while limiting the irradiation of vital organs. In this application, the longer half-life of radiolsotopes are more fit well for radionuclide therapy. To achieve this, researches have to be carried in a largor spectrum of radionuclides for diagnosis and therapy. In the context of rapidly growing nuclear medicine and strong demanding innovative radionuclides, a high-energy (100 MeV), high-intensity (-mA) accelerator with proton (PEFF at KAFRI). will be operating in 2011. The priorities of PEFP will include supporting the nuclear medicine research community by providing those radionuclides with current limited availability by means of a high-energy, high-intensity accelerator.

• Textile Coloration and Finishing
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• v.33 no.1
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• pp.1-9
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• 2021

This study aims to prepare the fabric with detoxification properties against chemical warfare agent by the simple treatment. For this purpose, polypropylene non-woven fabric(PP) was treated with polyethyleneimine(PEI) and guanidinylated PEI and detoxification properties of the guanidinylated PEI treated PP were evaluated using diisopropylfluorophosphate(DFP), as a chemical warfare agent simulant, and compared with the untreated and PEI treated PP. The half-lives of DFP on guanidinylated PEI treated PP and untreated PP were 334 min and 714 min, respectively. The half-life of DFP with guanidinylated PEI treated PP was 53.22% shorter than with untreated PP. This result shows that guanidine group in guanidinylated PEI treated PP was acted as a base catalyst for hydrolysis of DFP and decreased half-life of DFP. Therefore, it is expected that guanidinylated PEI treatment can be an simple pathway to prepare the detoxification fabric material for protective clothing against chemical warfare agents.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.97-103
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• 2018

BACKGROUND: Dissipation of acetamiprid and thiamethoxam in greenhouse grown chard samples was evaluated at 5 intervals including the pre-harvest interval after application. This study was conducted to determine the residue levels, the biological half-lives and dissipation rate of acetamiprid and thiamethoxam in chard under controlled conditions. METHODS AND RESULTS: Acetamiprid and thiamethoxam were applied in accordance with good agricultural practices for chard. Chard samples were collected at 0, 1, 2, 3, 5, 7, 10 and 14 days after application. Quantitaion was performed by HPLC-DAD system with C18 column. Limit of quantification (LOQ) of acetamiprid and thiamethoxam were both 0.02 mg/kg for chard. The recovery of acetamiprid and thiamethoxam were 77.8~107.5% and 94.3~108.6% at two concentration levels. The half-lives of pesticide dissipation in chard for two fields were 11.9 and 8.2 days for acetamiprid and 3.6 and 3.3 days for thiamethoxam respectively. The dissipation rate of acetamiprid and thiamethoxam were estimated according to the statistics method with a 95% confidence. CONCLUSION: Dissipation of acetamiprid and thiamethoxam in chard were determined under greenhouse. The concentration of acetamiprid and thiamethoxam in chards at 0 days after application were below specified by Korean MRL. Dissipation rate constant will be useful to set the pre-harvest residue limit for public health and consumer protection.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.88-92
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• 2015

This study investigated the thermal stabilities of the four limonoidal active compounds like azadirachtin A, azadirachtin B, deacetylsalannin and salannin and of the two alkaloidal active compounds like matrine and oxymatrine in commercial biopesticides at incubated conditions ($30^{\circ}C$, $35^{\circ}C$, $40^{\circ}C$, $45^{\circ}C$, and $54^{\circ}C$). Half-lives of the limonoidal compounds in biopesticide ranged from 25.6 to 220 days. And the total limonoid contents changed over 15% after 14 days at all the conditions in the tested biopesticide containing neem extract. On the contrary, half-lives of the alkaloidal compounds in biopesticide showed the ranges from 231 to 346 days. And total alkaloidal compounds in all the tested biopesticides containing Sophora flavescens extracts decomposed below 15% after 14 days incubation at $54^{\circ}C$.

• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.41-48
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• 2018

BACKGROUND: This study was performed to calculate the biological half-lives and regression coefficient of bistrifluron and cyenopyrafen dissipation in peach and to estimate the Pre-Harvest Residue Limits (PHRLs). METHODS AND RESULTS: The bistrifluron and cyenopyrafen were prepared on the basis of good agricultural practice for peach and treated with a single application. Peaches were harvested at 0, 1, 3, 5, 7, 10 and 14 days after application, prepared for analysis, and analyzed by HPLC-DAD. The limits of quantitation (LOQ) of bistifluron and cyenopyrafen were 0.02 mg/kg and 0.04 mg/kg, respectively. The recoveries of bistrifluron and cyenopyrafen were 99.5~108.7% and 88.4~98.9% at two different concentration levels. The biological half-lives of field I (Sejong) and field II (Pyeongtaek) were 6.1 and 7.0 days for bistifluron, and 6.3 and 7.0 days for cyenopyrafen, respectively. The 95% confidence intervals of dissipation rate constants of bistrifluron in peach were 0.0805~0.1457 and 0.0577~0.1417 for field I and field II, respectively, and those of cyenopyrafen were 0.0911~0.1278 and 0.0576~0.1417, respectively. CONCLUSION: Residue dissipation of bistrifluron and cyenopyrafen in peach were similar to that of correction to sample weight difference during the harvest periods. This study suggests that residue dissipation rate would be helpful to set the PHRLs that protect public health.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.122-129
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• 2020

BACKGROUND: Dissipation patterns of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry grown in plastic-covered greenhouse were evaluated at 7 intervals including the preharvest interval after application. This study was performed to determine the residue concentrations, half-lives and dissipation rates in strawberry for the harvest periods. METHODS AND RESULTS: Acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam were applied in accordance with critical good agricultural practices for strawberry. Strawberry samples were collected at 0, 1, 2, 3, 5, 7 and 10 days after application. Quantitaion was performed by HPLC/DAD and HPLC-MSMS system with C₁₈ column. The limit of quantitation (LOQ) values varied between were 0.00025~0.05 mg/kg on strawberry. The recoveries of acequinocyl, clothianidin, diflubenzuron, thiacloprid and thiamethoxam at two concentrations ranged from 70.9~104.9% on strawberry. The half-lives of pesticide dissipation on strawberry for two fields ranged from 1.3~8.2 days. The dissipation rates were evaluated according to the statistics method with a 95% confidence. CONCLUSION: The residue levels of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry at 0-day after application were below the specified values by Korean MRL. To estimate dissipation rate constant of pesticides on crop for harvest periods, it is important to set the pre-harvest residue limit for human health and consumer protection in Korea.