• KSBB Journal
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• v.20 no.3
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• pp.220-227
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• 2005

Doxorubicin is an anthracycline-family polyketide compound with a very potent anti-cancer activity, typically produced by Streptomyces peucetius. To understand the potential target biosynthetic genes critical for the doxorubicin everproduction, a doxorubicin-specific DNA microarray chip was fabricated and applied to reveal the growth-phase-dependent expression profiles of biosynthetic genes from two doxorubicin-overproducing strains along with the wild-type strain. Two doxorubicin-overproducing 5. peucetius strains were generated via over-expression of a dnrl (a doxorubicin-specific positive regulatory gene) and a doxA (a gene involved in the conversion from daunorubicin to doxorubicin) using a streptomycetes high expression vector containing a strong ermE promoter. Each doxorubicin-overproducing strain was quantitatively compared with the wild-type doxorubicin producer based on the growth-phase-dependent doxorubicin productivity as well as doxorubicin biosynthetic gene expression profiles. The doxorubicin-specific DNA microarray chip data revealed the early-and-steady expressions of the doxorubicin-specific regulatory gene (dnrl), the doxorubicin resistance genes (drrA, drrB, drrC), and the doxorubicin deoxysugar biosynthetic gene (dnmL) are critical for the doxorubicin overproduction in S. peucetius. These results provide that the relationship between the growth-phase-dependent doxorubicin productivity and the doxorubicin biosynthetic gene expression profiles should lead us a rational design of molecular genetic strain improvement strategy.

• Resources Recycling
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• v.24 no.2
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• pp.62-68
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• 2015

The high pure tin production was conducted from crude-tin containing waste solder by electro-refining process. The electro-refining process maintained at 0.2V produced tin with purity of 99.98%, whereas a little increase of voltage to 0.3 V resulted tin purity of 99.92%. The high pure tin of 3N in the present process was produced by fixing the voltage at 0.3V. Considering the high pure tin production, the current density was maintained within $100-120A/m^2$ with current efficiency of 94%. Addition of sulfuric acid of 20 ~ 25 g/L to the electrolyte solution was performed in order to keep Pb (lead) concentration below 100 mg/L in the final tin product. The anode slime generated during electro refining process was analyzed by X-ray diffraction (XRD) study to understand the phases of impurities in it. It detected the presence of Cu and Ag in the slime as in the form of $Cu_6Sn_5$, $Ag_3Sn$, whereas Pb occurred as $PbSO_4$ compound.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.284-289
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• 2017

Background: Compound FK506 is an immunosuppressant agent that is frequently used to prevent rejection of solid organs upon transplant. However, nephrotoxicity due to apoptosis and inflammatory response mediated by FK506 limit its usefulness. In this study, the protective effect of Korean Red Ginseng (KRG) against FK506-induced damage in LLC-PK1 pig kidney epithelial cells was investigated. Methods: LLC-PK1 cells were exposed to FK506 with KRG and cell viability was measured. Western blotting and RT-PCR analyses evaluated protein expression of MAPKs, caspase-3, and KIM-1. TLR-4 gene expression was assessed. Caspase-3 activities were also determined. The number of apoptotic cells was measured using an image-based cytometric assay. Results: The reduction in LLC-PK1 cell viability by $60{\mu}M$ FK506 was recovered by KRG cotreatment in a dose-dependent manner. The phosphorylation of p38, p44/42 MAPKs (ERK), KIM-1, cleaved caspase-3, and TLR-4 mRNA expression was increased markedly in LLC-PK1 cells treated with $60{\mu}M$ FK506. However, with the exception of p-ERK, elevated levels of p-p38, KIM-1, cleaved caspase-3, and TLR-4 mRNA expression were significantly decreased after cotreatment with KRG. Activity level of caspase-3 was also attenuated by KRG cotreatment. Moreover, image-based cytometric assay showed that apoptotic cell death was increased by $60{\mu}M$ FK506 treatment, whereas it was decreased after cotreatment with KRG. Conclusion: Taken together, these results suggest that the molecular mechanism of KRG in the FK506-induced nephrotoxicity may lead to the development of an adjuvant for the inhibition of adverse effect FK506 in the kidney.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.43-49
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• 2019

In this study, a new approach using graphene oxide (GO) powder-composited Sn-3.0Ag-0.5Cu(in wt.%) solder paste for improving the bending reliability of solder joints between a flexible substrate and small outline package (SOP) was suggested. The GO addition slightly affected the melting temperature, however, the change in the melting temperature was not significant. Meanwhile, we observed the addition of GO could suppress IMC growth and IMC thickness of solder joint during the reflow process. Moreover, the cyclic bending test was also performed for evaluation of reliability in solder joint and we could improve the cyclic bending reliability of solder joint by adding GO powders. For 0.2 wt.% of GO added to the solder joint, the bending lifetime was increased to 20% greater than that without GO. Pull strength and ductility of the solder joint with GO were also higher than those of the joint without GO and it was assumed that this effect by adding GO could contribute to improve cyclic bending reliability of solder joint.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.545-553
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• 1993

The metalaxyl seed-soaking treatment markedly increased the root-mat formation of the young rice seedling(8- to l0-day-old) for machine transplanting. This experiment was conducted to find out a possible rooting mechanism of the young rice seedling in relation to the exogenous metalaxyl seed-soaking treatment. The rice seeds of Hwaseongbyeo variety were soaked in the solution of metalaxyl for 24 hours at room temperature. Metalaxyl(25% wettable powder), a fungicide, was used at the concentration of 200ppm as a promoting substance on the root-mat formation of the young rice seedling. Seeding rate of the young rice seedling was 220g per seed tray(30${\times}$60${\times}$depth 3cm). Metalaxyl seed treatment was highly effective in root initiation and elongation of the young rice seedling in terms of root activity, the number and length of root, and amino acid content of roots. The exogenous metalaxyl application would also increase the chlorophyll content and photosynthetic rate in the young rice seedling. Those factors resulted in vigorous root-mat formation of the young rice seedling. In particular, alanine is a lead compound of metalaxyl which biochemically plays an important role in energy intermediate of the rice plant. Alanine conjugation with a glucose (N-${\beta}$-glucoside) is probably the mechanism in enhancement of initiation and elongation of rice roots of young rice seedling.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.63-63
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• 2003

Opuntia ficus-indicavar. saboten Makino (Cactaceae) is a tropical or subtropical plant that has been widely used as folk medicine for the treatment of diabetes, asthma, burn, edema and gastritis. The purposes of the present study were to identify antioxidant constituents from fruits and stems of the plant cultivated in Cheju island, Korea, and examine their in vitro neuroprotective activities. Using a chromatographic fractionation method, ten chemical constituents were isolated from ethyl acetate extracts. By means of chemical and spectroscopic methods, those were identified as eight flavonoids such as kaempherol (a), quercetin (b), kaempferol 3-methyl ether (c), quercetin 3-methyl ether (d), narcissin (e), dihydrokaernpferol (f), dihydroquercetin (g) and erioclictyol (h), and two terpenoids such as 3-oxo-${\alpha}$-ionol-${\beta}$-d-glucopyranoside (i) and roseoside (j). Among the isolated compounds, comrounds c~e and h~j were those reported for the first titre from the plant. Compounds b, d and g showed DPPH free radical scavenging activities with IC$\sub$50/ values of 28, 19 and 31, ${\mu}$M respectively. Compounds d and g also inhibited iron-dependent lipid peroxidation with IC$\sub$50/ values of 2.4 and 3.5 ${\mu}$M. In a primary rat cortical neuronal cell culture system, compounds b, d and g inhibited xanthine/xanthine oxidase-induced (IC$\sub$50/ values of 18.2, 2.1 and 54.6 ${\mu}$M) and H$_2$O$_2$-induced (IC$\sub$50/ values of 13.6, 1.9 and 25.7 ${\mu}$M) cytotoxicities. In addition, compounds d and g inhibited NMDA-induced excitotoxicity by 21 and 33%, and only compound d inhibited growth factor withdrawal-induced apoptosis by 31% at a tested concentration of 3 ${\mu}$M. The results suggest that the antioxidant constituents with in vitroneuroprotective activities may serve as lead chemicals for the development of neuroprotective agent.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.353-362
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• 2023

TOC, which can measure more than 90% of organic substances, can be measured quickly and easily,replacing BOD and COD, which were indicators of organic pollutants. According to water quality pollution control standards, when measuring TOC, if the inorganic carbon ratio in the sample is over 50%, the NPOC (Non-Purgeable Organic Carbon) method should be used. If volatile organic compounds (VOCs) are present at a certain concentration, the TC-IC (subtracting inorganic carbon from total carbon) method should be used. To validate the limitations of these analytical conditions, experiments were conducted by varying the ratio of TOC to IC in purified water and measuring the concentration of TOC in test solutions. The results showed no significant difference between the TC-IC method and the NPOC method. When measuring samples with added VOC standard solutions, it was observed that the carbon loss due to purging was not significant when using the NPOC method. Therefore, it is concluded that the choice of analytical method does not lead to significant differences when VOCs are present in the sample. To account for potential variations in results based on water quality pollution control standards and regulations regarding the approval and testing of environmental measurement devices, a comparison of field sample concentration values was made using two widely used types of TOC analyzers in Korea. The results showed variations of 0.02 to 0.83 mg/L between methods depending on the manufacturer, highlighting the need for caution when selecting an instrument.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.61-68
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• 2023

In this study, Sn-3.5Ag-15.0Fe composite solder was manufactured and applied to TLP bonding to change the entire joint into a Sn-Fe IMC(intermetallic compound), thereby applying it as a high-temperature solder. The FeSn₂ IMC formed during the bonding process has a high melting point of 513℃, so it can be stably applied to power modules for power semiconductors where the temperature rises up to 280℃ during use. As a result of applying ENIG surface treatment to both the chip and substrate, a multi-layer IMC structure of Ni₃Sn₄/FeSn₂/Ni₃Sn₄ was formed at the joint. During the shear test, the fracture path showed that cracks developed at the Ni₃Sn₄/FeSn₂ interface and then propagated into FeSn₂. After 2hours of the TLP joining process, a shear strength of over 30 MPa was obtained, and in particular, there was no decrease in strength at all even in a shear test at 200℃. The results of this study can be expected to lead to materials and processes that can be applied to power modules for electric vehicles, which are being actively researched recently.

• Korean Journal of Environmental Agriculture
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• v.14 no.2
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• pp.202-212
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• 1995

In order to elucidate the degrading characteristics of the pyrethroid acaricide-insecticide, acrinathrin in two different types of soils, Soil A(pH, 5.8; organic matter, 3.4%; C.E.C., 115 mmol(+)/kg soil; texture, sandy loam) and Soil B(pH, 5.7; organic matter, 2.0%; C.E.C., 71 mmol(+)/kg soil; texture, sandy loam), residualities of the non-labeled compound under the field and laboratory conditions, extractability with organic solvents and formation of non-extractable bound residues, and degradabilities of [$^{14}C$]acrinathrin as a function of aging temperature and aging period were investigated. The half lives of acrinathrin in Soil A treated once and twice were about 18 and 22 days and in Soil B about 13 and 15 days, respectively, in the field, whereas, in the laboratory, those in Soil A and B were about 36 and 18 days, respectively, suggesting that the compound would be non-persistent in the environment. The amounts of $^{14}CO_2$ evolved from [$^{14}C$]acrinathrin in Soil A and B during the aging period of 24 weeks were 81 and 62%, respectively, of the originally applied $^{14}C$ activity, and those of the non-extractable soil-bound residues of [$^{14}C$]acrinathrin were about 70% of the total $^{14}C$ activity remaining in both soils, increasing gradually with the aging period. Degradation of [$^{14}C$]acrinathrin in both soils increased with the aging temperature. Three degradation products of m/z 198(3-phenoxy benzaldehyde), m/z 214(3-phenoxybenzoic acid), and m/z 228(methyl 3-phenoxybenzoate) as well as an unknown were detected by autoradiography of acetone extracts of both soils treated with [$^{14}C$]acrinathrin and aged for 15, 30, 60, 90, 120, and 150 days, respectively, and the degradation pattern of acrinathrin was identical in both soils. Acrinathrin in soil turned out to be degraded to 3-phenoxybenzaldehyde cyanohydrin by hydrolytic cleavage of the ester linkage adjacent to the $^{14}C$ with a cyano group, the removal of hydrogen cyanide therefrom led to the formation of 3-phenoxybenzaldehyde as one of the major products, and the subsequent oxidation of the aldehyde to 3-phenoxybenzoic acid, followed by decarboxylation would lead to the evolution of $^{14}CO_2$.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.1-11
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• 2001

New technologies will have a large impact on the discovery of new herbicide site of action. Genomics, combinatorial chemistry, and bioinformatics help take advantage of serendipity through tile sequencing of huge numbers of genes or the synthesis of large numbers of chemical compounds. There are approximately $10^{30}\;to\;10^{50}$ possible molecules in molecular space of which only a fraction have been synthesized. Combining this potential with having access to 50,000 plant genes in the future elevates tile probability of discovering flew herbicidal site of actions. If 0.1, 1.0 or 10% of total genes in a typical plant are valid for herbicide target, a plant with 50,000 genes would provide about 50, 500, and 5,000 targets, respectively. However, only 11 herbicide targets have been identified and commercialized. The successful design of novel herbicides depends on careful consideration of a number of factors including target enzyme selections and validations, inhibitor designs, and the metabolic fates. Biochemical information can be used to identify enzymes which produce lethal phenotypes. The identification of a lethal target site is an important step to this approach. An examination of the characteristics of known targets provides of crucial insight as to the definition of a lethal target. Recently, antisense RNA suppression of an enzyme translation has been used to determine the genes required for toxicity and offers a strategy for identifying lethal target sites. After the identification of a lethal target, detailed knowledge such as the enzyme kinetics and the protein structure may be used to design potent inhibitors. Various types of inhibitors may be designed for a given enzyme. Strategies for the selection of new enzyme targets giving the desired physiological response upon partial inhibition include identification of chemical leads, lethal mutants and the use of antisense technology. Enzyme inhibitors having agrochemical utility can be categorized into six major groups: ground-state analogues, group specific reagents, affinity labels, suicide substrates, reaction intermediate analogues, and extraneous site inhibitors. In this review, examples of each category, and their advantages and disadvantages, will be discussed. The target identification and construction of a potent inhibitor, in itself, may not lead to develop an effective herbicide. The desired in vivo activity, uptake and translocation, and metabolism of the inhibitor should be studied in detail to assess the full potential of the target. Strategies for delivery of the compound to the target enzyme and avoidance of premature detoxification may include a proherbicidal approach, especially when inhibitors are highly charged or when selective detoxification or activation can be exploited. Utilization of differences in detoxification or activation between weeds and crops may lead to enhance selectivity. Without a full appreciation of each of these facets of herbicide design, the chances for success with the target or enzyme-driven approach are reduced.