• Korean Journal of Environmental Agriculture
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• v.34 no.1
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• pp.1-5
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• 2015

BACKGROUND: The stabilities of the two alkaloidal insecticides of S. flavescens including matrine and oxymatrine are important factor to establish expiry date and usage manual for crop protection. However, the environmental stability of the compounds had not been studied with the extract and its commercial biopesticide. METHODS AND RESULTS: The environmental stabilities of the two alkaloids were performed with extract of S. flavescens, and its two commercial biopesticides both in controlled aquatic and soil conditions. The half-lives of the total matrines for the extract and its two commercial biopesticides were estimated over 200 days both under aerobic and anaerobic water condition. Under dry soil condition, the initial decay rates of the matrines were calculated 0.0804-0.1275 ($t_{1/2}$ 5.4-8.6 days), and the half-lives under wet soil condition were calculated 33.0-231 days. Total soil bacteria on the wet soil ranged 6.0-8.0 log CFU/g-soil during the experiments period. CONCLUSION: The aquatic mixture of the extract showed excellent stability both with the extract and its biopesticides, however, the stability of soil mixture were shorter than the aquatic mixture, suggesting that soil metal consider as a catalyst for the degradation of the two alkaloids.

• Biomolecules & Therapeutics
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• v.2 no.4
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• pp.310-315
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• 1994

The pharmacokinetics and tissue distribution of DA-3030 (recombinant human granulocyte colony-stimulating factor, rhG-CSF, recently manufactured by Dong-A research laboratory of Dong-A Pharmaceutical Company) were compared with reported data in the literature. After intravenous(i.v.) administration of DA-3030, at dose of 5, 10 and 100 $\mu\textrm{g}$/kg to rats, some pharmacokinetic parameters, such as terminal half-lives(1.05, 1.19 and 1.83 hr, respectively) and clearance (84.0, 54.8 and 45.5 mι/hr/kg, repectively), were dose-dependent. This could be due to the saturable metabolism of DA-3030 in rats. Similar results were also reported. After subcutaneous(s.c.) and intramuscular(i.m.) administrations of DA-3030, 10 $\mu\textrm{g}$/kg to rats, the extent of bioavailability(absolute bioavailability) were incomplete; the values were 23.3 and 18.2% after s.c. and i.m. injections, respectively, due to the degradation of DA-3030 by protease. After 7-consecutive day i.v. administrations of DA-3030, 10 $\mu\textrm{g}$/kg/day, to rats, the plasma concentrations and pharmacokinetic parameters of DA-3030 were not significantly different from those in single administration. In mice and dogs at DA-3030 dose of 10 $\mu\textrm{g}$/kg, the plasma concentrations of DA-3030 were also declined rapidly with terminal half-lives of 1.31 and 1.15 hr, respectively. DA-3030 was highly concentrated in the kidney after i.v. administration of DA-3030, 10 $\mu\textrm{g}$/kg, to rats, and the results were similar to those obtained using radiolabelled rhG-CSF in the literature. Above data indicate that DA-3030 has similar properties to rhG-CSF manufactured by other companies in view of pharmacokinetics.

• The Journal of the Korean dental association
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• v.57 no.10
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• pp.613-622
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• 2019

The vitamin K antagonist (VKA), cumadin, or warfarin, is the only antithrombotic drug that can be orally administered and has excellent effective for decades. However, it is cumbersome to periodically inspect the prothrombin time (PT) order to maintain adequate concentrations that do not cause bleeding, takes a few days to indicate therapeutic effects, gets affected by several factors such as food and drugs etc, and narrow in the therapeutic range. Although recently in development, the non-vitamin K antagonist anticoagulants(NOACs) exhibit a rapid onset of action and have relatively short half- lives compared to Coumadin. Because of these pharmacokinetic properties, it is possible to modify an individual's anticoagulation status quite rapidly, minimizing the period where the anticoagulation activity is therapeutically suboptimal. And the short half -lives of these drug allow for the relatively rapid reduction of their anticoagulation effects. There are currently no published clinical trials specifically assessing the bleeding risks associated with dental procedures for patients taking the NOACs. It is not necessary to interrupt NOAC medication for dental procedures that are likely to cause bleeding, but which have a low risk of bleeding complications. Because the bleeding risk for these procedures is considered to be low, the balance of effects is in favour of continuing the NOAC treatment without modification, to avoid increasing the risk of a thromboembolic event. The patients should be advised to miss(apixaban or dabigatran) or delay(rivaroxaban) a dose of their NOAC prior to dental procedures that are likely to cause bleeding and which have a higher risk of bleeding complications. Because the risk of bleeding complications for these procedures is considered to be higher, the balance effects is in favour of missing or delaying the pretreatment NOAC dose. The interruption is only for a short time to minimize the effect on thromboembolic risk.

• Progress in Medical Physics
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• v.32 no.4
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• pp.145-152
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• 2021

Purpose: During the treatments of cancer patients with a linear accelerator (LINAC) using photon beams with energies ≥8 MV, the components inside the LINAC head get activated through the interaction of photonuclear reaction (γ, n) and neutron capture (n, γ). We used spectroscopy and measured the dose rate for the LINAC in operation after the treatment ended. Methods: We performed spectroscopy and dose rate measurements for three units of LINACs with a portable high-purity Germanium (HPGe) detector and a survey meter. The spectra were obtained after the beams were turned off. Spectroscopy was conducted for 3,600 seconds, and the dose rate was measured three times. We identified the radionuclides for each LINAC. Results: According to gamma spectroscopy results, most of the nuclides were short-lived radionuclides with half-lives of 100 days, except for ⁶⁰Co, ⁶⁵Zn, and ¹⁸¹W nuclides. The dose rate for three LINACs obtained immediately in front of the crosshair was in the range of 0.113 to 0.129 µSv/h. The maximum and minimum dose rates measured on weekends were 0.097 µSv/h and 0.092 µSv/h, respectively. Compared with the differences in weekday data, there was no significant difference between the data measured on Saturday and Sunday. Conclusions: Most of the detected radionuclides had half-lives <100 days, and the dose rate decreased rapidly. For equipment that primarily used energies ≤10 MV, when the equipment was transferred after at least 10 minutes after shutting it down, it is expected that there will be little effect on the workers' exposure.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.1
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• pp.9-16
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• 2001

Chromium exposure can be in the forms of environmental pollution and occupational exposure. The harmful effects of chromium on the body greatly differ depending on its valence or solubility. Accordingly, the recommended permissible exposure limit for each chromium compound is different. This study investigated the increase or decrease of distribution and excretion of total chromium exposed simultaneously the soluble Cr+6 and Cr+3 compounds. There were no difference of total chromium concentration in plasma, red bloods cells, urine, organs between simultaneously injected and individually injected soluble Cr+6 and Cr+3 compound. The chromium clearances in urine also showed that there were two phases in the two groups. In the first phase, biological half lives of the total chromium of the two groups have been similar within 24 hr., but in the second phase, biological half life of the group injected simultaneously was 62.7 hr. and was less than that of the other group's 188.3 hr. The average concentration of total chromium in plasma was same with the control, and that of RBCs was $0.218nmol/m{\ell}$ and was slightly increased in comparison with $0.121nmol/m{\ell}$ of the control, which was not statistically significant. As a result, there were no differences of distribution and excretion of chromium between the group exposed simultaneously and the other group exposed separately the soluble Cr+6 and Cr+3 compounds. The biological half life of chromium of the former group in urine was less than that of the other group.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.220-226
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• 2003

The residue patterns of procymidone, chlorpyrifos and cypermethrin in peaches were examined. The pesticides were sprayed at 15 days before harvest and then were determined the residue at 0, 1, 2, 3, 5, 7, 10 and 15 days after pesticide application and calculated their $DT_{50}$. Also, the degradation patterns at $4^{\circ}C$ and $20^{\circ}C$ during storage period were compared. Biological half-lives of procymidone, chlorpyrifos and cypermethrin in peaches during the cultivation period were 3.1, 7.2 and 10.4 days, respectively. The biological half -life of procymidone was shorter than the others. During the storage period, half-lives of procymidone, chlorpyrifos and cypermethrin were 16.0, 14.3 and 13.1 days at $4^{\circ}C$ and 4.6, 10.2 and 12.9 days at $20^{\circ}C$, respectively. The degradation rates of these three pesticides in storage period were slower than them in cultivation period. Removal rates were $22.2{\sim}82.9%$ by tap water, and $12.5{\sim}88.8%$ by detergent solution.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.113-119
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• 2004

Persistence of the triazole fungicides, bitertanol and tebucnazole was investigated after their application at recommended and double rate on greenhouse-grown peppers. The half-life of bitertanol and tebuconazole on peppers at recommended and double rate was $5.2{\sim}6.1$ and $4.6{\sim}5.2$ days, respectively. Half-lives of bitertanol and tebuconazole on pepper leaves $(16.8{\sim}22.5\;days)$ was longer than those in the peppers. Residual concentration of bitertanol and tebuconazole on pepper leaves 24 days after application were 10.1 and 17.5 mg/kg, respectively, and these levels were higher than MRL which had been established at 3.0 and 5.0 mg/kg in Korea. Pattern of dissipation was well fitted to the first-order kinetics. In household washing experiment with surfactant, dislodgeable portions on pepper leaves of bitertanol and tebuconazole were occupied 36% and 48% of the residues found 24 days after application.

• Korean Journal of Weed Science
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• v.14 no.4
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• pp.298-313
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• 1994

Residue of herbicide napropamide [N,N-dimethyl-2-(1-napthoxy)-propionamide] and change of micro-organism were investigated in upland soil under different environmental conditions. Half-lives of degradation were 28.3 days in the sterile soil and 14.6 days in the nonsterile soil, respectively. These results suggest that microorganism remarkably affected the decomposition of napropamide. Napropamide was rapidly degraded in order of 60% > 80% ${\geq}$ 40% soil moisture content of field water-holding capacity. Numbers of bacteria and total microbes in 60% moisture content was more than those in 40% moisture content. The more the napropamide degradation was rapid in lower soil pH. The total number of microorganism increased by lapse of time after treatment of napropamide at pH 5.5. The decomposition rate of napropamide was rapid in the order of $27^{\circ}C$ > $37^{\circ}C$ > $17^{\circ}C$. At $17^{\circ}C$ of soil temperature actinomycetes in napropamide treatment plot was more than these in nontreatment plot and also at $27^{\circ}C$ and $37^{\circ}C$ bacteria in napropamide treatment plot was more than those in nontreatment plot. Napropamide degradation was more rapid and number of microorganism was more abundant at the concentration of 10ppm than at that of 20ppm. The half-life of napropamide was longer in the clay loam soil than in the silty loam soil. The half times in laboratory test than in upland field. Numbers of microbes in the experiment under all the test environmental condition was not significantly different between treatment and nontreatment of napropamide.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.664-668
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• 2001

The physical and chemical stabilities of carthamin of red pigment from safflower petals were investigated at various conditions of pHs, temperatures, inorganic ions, sugars, light and polysaccharides. The half-life values at pH 3.0, 5.0, 9.0 and 11.0 were 5.3, 5.0, 11.0 and 45.0 h, respectively, at $25^{\circ}C$. Therefore, carthamin is unstable at acidic condition. Carthamin was red, orange and yellow at acidic, neutral and alkaline solutions, respectively. At pH 3.0, carthamin was thermally unstable and the half lives were 3.62, 9.05 and 48.2min at $90^{\circ}C$, $70^{\circ}C$ and $50^{\circ}C$, respectively. Among various inorganic ions, $Al^{3+}$ stabilized carthamin at acidic condition. At pH 5.0, carboxymethylcellulose prolonged the half-lives of carthamin at $25{\sim}90^{\circ}C$. Carthamin was very sensitive to light (20,000 lux) and the half-life was 2.32 min at pH 3.0.

• Journal of Applied Biological Chemistry
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• v.55 no.4
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• pp.235-239
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• 2012

While cultivating crops, it is important to predict the biological half-lives of applied pesticides to ensure the safety of agricultural products. Dissipation patterns of the triazole fungicides, such as diniconazole and metconazole, during the cultivation of apple were established by utilizing the dissipation curve. As well as, the biological half-lives of the pesticides in apples were calculated using the residue amounts of them. The apples were harvested from 0 to 14 days after spraying diniconazole (WP) and metconazole (SC) at a recommended and three times of the recommended dose. Initial concentrations of diniconazole in apple were 0.09 and 0.15 mg/kg at a recommended and three times of the recommended dose, respectively, which were below MRL 1.0 mg/kg established by KFDA. The equations of biological half-life were $C_t=0.0811e^{-0.179x}$(half life: 3.9 days) and $C_t=0.1451e^{-0.148x}$ (half life: 4.7 days), respectively. In case of metconazole, initial concentrations in apple were 0.10 and 0.25 mg/kg, below MRL 1.0mg/kg, and biological half-life equations were $C_t=0.0857e^{-0.055x}$ (half life: 12.6 days) and $C_t=0.2304e^{-0.052x}$ (half life: 13.3 days), respectively. Therefore, when triazole fungicides were applied during the cultivation of apple, the biological half-life need to be calculated with the optimal equation model.