• Toxicological Research
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• v.29 no.1
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• pp.53-60
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• 2013

Studies on milk transfer of drugs in non-human primates (NHPs) are among the crucial components in the assessment of peri- and postnatal toxicity because of the similarity between NHPs and humans. To evaluate the milk transfer of valproic acid (VPA) in NHPs, the toxicokinetics of VPA, an antiepileptic drug, were studied in pregnant cynomolgus monkeys. VPA was administered once daily to pregnant cynomolgus monkeys at doses of 0, 30, 90, and 270 mg/kg by oral gavage from Day 100 of gestation (GD 100) to Day 31 of lactation (LD 31). Concentrations of VPA and its metabolite, 4-ene-VPA, in the maternal plasma on GD 100, GD 140, and LD 30, and concentrations of VPA and 4-ene-VPA in the offspring plasma and milk on LDs 30 and 31, respectively, were quantified using liquid chromatography tandem mass spectrometry (LC/MS/MS). After administration of a single oral dose of VPA to pregnant monkeys on GD 100, the concentrations of VPA and 4-ene-VPA were generally quantifiable in the plasma of all treatment groups up to 24 hr after administration, which showed that VPA was absorbed and that the monkeys were systemically exposed to VPA and 4-ene-VPA. After administration of multiple doses of VPA to the monkeys, VPA was detected in the pup's plasma and in milk taken on LD 30 and LD 31, respectively, which showed that VPA was transferred via milk, and the pup was exposed to VPA. Further, the concentration of VPA in the milk increased with an increase in the dose. Extremely low concentrations of 4-ene VPA were detected in the milk and in the pup plasma. In conclusion, pregnant monkeys were exposed to VPA and 4-ene-VPA after oral administration of VPA at doses of 30, 90, and 270 mg/kg/day from GD 100 to LD 31. VPA was transferred via milk, and the VPA exposure to the pup increased with an increase in the dose of VPA. The metabolite, 4-ene VPA, was present in extremely low concentrations (< 0.5 ${\mu}g/ml$) in the milk and in the pup plasma. In this study, we established methods to confirm milk transfer in NHPs, such as mating and diagnosis of pregnancy by examining gestational sac with ultrasonography, collection of milk and pup plasma and determination of toxicokinetics, using cynomolgus monkeys.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.8-15
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• 1994

The mode of safening action and potency of the 1, 8-naphthalic anhydride(NA) were investigated in corn(Zea mays) and soybean(Glycine max) treated with herbicide bensulfuron[2-{{{{{(4,6-dimethoxy-2-pyrimidinyl)amino}carbonyl}amino}sulfonyl}methyl}benzoic acid] and imazaquin[2-{4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl} 3-quinolinonecarboxylic acid]. Seed dressing with 0.2%(w/w) NA showed successful protection in corn against injury from herbicide bensulfuron and imazaquin but not in soybean. Safening factors of NA against bensulfuron and imazaquin were 10.2 and 5.0, respectively, in corn, while they were both 1.3 in soybean. In vivo, Glutathione-S-transferase(GST) activity of NA-treated corn and soybean increased 1.8-and 1.3-fold, respectively, but the activity was not affected by the herbicides in vitro. Acetolactate synthase(ALS) levels of NA-treated corn was increased 1.3-fold, but not changed in soybean. Tolerance of ALS activity to the herbicides was slightly greater in ALS obtained from NA-treated corn than that from the untreated, whereas the difference was not found in soybean. A significant increase of ACCase due to NA occurred in corn, but not in soybean. The herbicides did not affect in vitro ACCase activity.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.97-103
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• 2005

Antioxidative responses of transgenic tobacco plants expressing both superoxide dismutase (SOD) and ascorbate peroxidase (APX) in chloroplasts was investigated with several herbicides. In greenhouse test, tolerance of SOD/APX-overexpressed tobacco (CA) to photosystem (PS) I inhibitor paraquat was increased by about 40%. However, any response differences between CA and wild type (WT) tobacco was not observed in a treatment with PS II inhibitors (bromoxynil, diuron and bromacil), chlorophyll biosynthesis inhibitor(oxyfluorfen), carotenoid biosynthesis inhibitor (fluridone) and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase inhibitor (glyphosate). This tendency was also similar in the growth chamber test of low light intensity, using paraquat and diuron. That is, increased antioxidant activity of CA was shown only in paraquat treatment. When paraquat was foliar-treated to 6 to 9-leaf stage plant, the third to fourth placed leaf from shoot tip showed relatively higher antioxidant activity. Ascorbate supplemented to paraquat solution alleviated the phytotoxicity with a similar range in both CA and WT. In conclusion, CA specifically responded to oxidative stress induced by paraquat among tested herbicides in a whole plant assay.

• Journal of Adhesion and Interface
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• v.17 no.1
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• pp.7-14
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• 2016

Epoxy composites with concentrations of 5-70 wt% of silica particles were prepared in order to improve mechanical property and poor thermal stability. The mechanical and thermal properties were investigated and compared to the corresponding properties of neat epoxy composite. Furthermore, the effects of silane compound treatment on silica particles were observed by the experimental results of the tensile strength, glass transition temperature, and thermal stability of epoxy composite. Tensile strength of epoxy composites was measured by universal testing machine (UTM) and after that, the structure and morphology analysis of epoxy nanocomposites were analyzed by field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS). The increased solid content of CA0030 particle improved the tensile strength of epoxy/ modified composites to give 30-50 MPa. The thermal expansion coefficients (CTE) of neat epoxy resin and epoxy/silica composites measured with a thermomechanical analyzer (TMA) showed that the incorporation of silica particles was helpful to reduce the CTE of neat epoxy resin.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.119-124
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• 2018

The production of methyl N-phenyl carbamate by an oxidative carbonylation method of aniline and methanol is of great interest as an environmentally friendly process that can replace the monomer production process of a polymer produce using conventional phosgene. In this study, heterogeneous catalysts were prepared by using Y-zeolite, $SiO_2$, $Al_2O_3$ as support, and oxidative carbonylation continuous operation from aniline and methanol was attempted using the prepared heterogeneous catalyst. Batch reactor was used to determine the support, and various reaction conditions such as reaction temperature, reaction pressure, and effect of promoter were established using palladium catalyst. A reaction kinetics study was conducted under optimum reaction conditions. The basic data for carbamate process development were obtained by performing continuous operation for a long time under established reaction condition.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.232-240
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• 2012

Bio-diesel (BD) is the mono alkyl esters of long chain fatty acids derived from renewable feed stocks like vegetable oils or animal fats. Bio-diesel shows poorer fuel properties than that of diesel fuel in a cold condition. For the diesel fuel, many cold flow improvers have been developed; however, since primary ingredients of bio-diesel are different from those of the diesel fuel, there is a limit to the cold flow improvement when the same cold flow improvers are added to bio diesel. In this study, to improve low temperature properties of bio-diesel, we developed a cold flow improver using an alkyl methacrylate monomer, prepared via ester reaction, and maleic anhydride and also conducted a ring opening reaction using amine. We characterized the products using $^1H-NMR$, FT-IR and GPC methods. In addition, the cold flow improvements of the products in Soybean BD and Palm BD in the concentration rage of 1000~10000 ppm were investigated. It was found that the addition of LMA2SMA6MA2-C8A in Soybean BD improved the pour point by $12.5\;^{\circ}C$.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2013.10a
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• pp.218-232
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• 2013

• Polymer Science and Technology
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• v.10 no.6
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• pp.782-790
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• 1999

• Polymer Science and Technology
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• v.10 no.6
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• pp.732-742
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• 1999

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.424-424
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• 2005