• The Korea Journal of Herbology
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• v.21 no.4
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• pp.27-36
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• 2006

Objectives : This study was performed for the investigation of anticancer effects of methanol extract of Rheum Rhizoma (MeOH-RR) on a human liver cancer cell line (HepG2). Methods : To study the cytotoxic effect of MeOH-RR on HepG2 cells, the cell viability was determined by XTT reduction method and trypan blue exclusion assay. The cleavage of poly ADP-ribose polymerase (PARP), a substrate for caspase-3 and a typical sign of apoptosis, and the activation of procaspase-3, -8 and -9 were examined by western blot analysis. Furthermore, MeOH-RR-induced apoptosis was confirmed by DNA fragmentation. The release of cytochrome c from mitochondria to cytosol, the level of Bcl-2 and Bax were examined by western blot analysis. Results : MeOH-RR reduced proliferation of HepG2 cells in a dose-dependent manner at 24 h and 48 h treatment. MeOH-RR induced the activation of caspase-3, -8, and -9 and the cleavage of poly ADP-ribose polymerase (PARP), a substrate for caspase-3. Furthermore, treatment with MeOH-RR resulted in internucleosomal DNA fragmentation, evidenced by the formation of a DNA ladder on agarose gel, a hallmark of cells undergoing apoptosis. MeOH-RR downregulated Bcl-2, upregulated Bax, and increased the release of cytochrome c from the mitochondria into cytosol in a dose-dependent manner. Moreover, MeOH-RP increased caspase-3 activity. Conclusion : There results suggest that MeOH-RR induce apoptosis via mitochondrial pathway and caspase-3-dependent pathway in HepG2 cells. There results suggest that MeOH-RR is potentially useful as a chemotherapeutic agent in human liver cancer.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.370-376
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• 1998

The extraction yield of MeOH extract of green teas, oolong tea and black tea were 3 to 5, 4 to 5, and 5 to 7 fold higher than those of EtOH and EtAC extract, respectively. The amount of total catechins of EtAC extract of the black tea, and of the green teas and oolong tea were three- and two-fold higher than that of EtOH or MeOH extract of the corresponding teas, respectively. The antioxidative activities of EtOH, MeOH and EtAc extract were considerably higher than that of BHT and $dl-{\alpha}-tocopherol$ at 200 ppm level. The antioxidative activities of EtOH and MeOH extract at 200 and 500 ppm level, and of EtAc extract at 200 ppm level varied depending on the type of tea as follows : green tea I > green tea II > green tea III > oo-long tea> black tea. The antioxidative activity increased as the content of EGC increased. But the antioxidative activity of MeOH extract at 1000 ppm level, and of EtAc extract at 500 and 1000 ppm level were not affected by the content of EGC and EGCG.

• Korean Journal of Materials Research
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• v.6 no.7
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• pp.733-741
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• 1996

In this study MeV Si self ion implantations were done to reveal the intrinsic behavior of defect formation by excluding the possibility of chemical interactions between substrate atoms and dopant ones. Self implantations were conducted using Tandem Accelerator with energy ranges from 1 to 3 MeV. Defect formation by high energy ion implantation has a significant characteristics in that the lattice damage is concentrated near Rp and isolated from the surface. In order to investigate the energy dependence on defect formation, implantation energies were varied from 1 to 3 MeV under a constant dose of $1{\times}10^{15}/cm^2$. RBS channe!ed spectra showed that the depth at which as-implanted damaged layer formed increases as energy increases and that near surface region maintains better crystallinity as energy increases. Cross sectional TEM results agree well with RBS ones. In a TEM image as-implanted damaged layer appears as a dark band, where secondary defects are formed upon annealing. In the case of 2 MeV $Si^+$ self implantation a critical dose for the secondary defect formation was found to be between $3{\times}10^{14}/cm^24$ and $5{\times}10^{14}/cm^2$. Upon annealing the upper layer of the dark band was removed while the bottom part of the dark band did not move. The observed defect behavior by TEM was interpreted by Monte Carlo computer simulations using TRIM-code. SIMS analyses indicated that the secondary defect formed after annealing gettered oxygen impurities existed in silicon.

• Journal of the Korean Chemical Society
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• v.29 no.6
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• pp.565-574
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• 1985

The rates of reaction between 4-substituted-2,6-dinitrochlorobenzenes with para-substituted anilines in methanol-acetonitrile mixtures were measured by conductometry. It was observed that the rate constant increases in the order of X = 4-$NO_2 {\gg}4-CN {\gg}4- CF_3$, where X is a substituent in the substrate. The rate constant also increases in the order of Y = p-O$CH_3{\gg}p- CH_3{\gg}H {\gg}p-Cl{\gg}m- NO_2$, where Y is a substituent in the aniline ring. Kinetic studies in the methanol-acetonitrile solvent system with various nucleophiles showed that the N-C bond forming step is making a great contribution to the overall second order rate constant. The electrophilic catalysis by methanol probably consists of the hydrogen bonding between alcoholic hydrogen and leaving chloride in the transition state. The nucleophilic catalysis by methanol may be ascribed to the formation of hydrogen bonds between alcoholic oxygen and hydrogens of amines in the transition state. All these experimental facts are supporting the operation of $S_N$Ar machanism with the second step being the rate determining. This mechanism can be successfully fitted to the PES model.

• Journal of Life Science
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• v.26 no.8
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• pp.948-954
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• 2016

We investigated the flavonoid and phenol contents and antioxidant effect of wine by-product extract. Antioxidant effects were measured with 1,1-diphenyl-2-picryhydrazyl (DPPH) and 2.2'-azino-bis(3-ethylbenothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS+) assays. Cellular reactive oxygen species (ROS) were measured with the dichlorofluorescein-diacetate (DCFH-DA) assay. The flavonoid and phenol contents of the methanol (MeOH) extract were greater than those of the acetone+methylene chloride (A+M) extract. Among fractions, the 85% aqueous methanol (85% aq. MeOH) fraction contained the highest flavonoid contents, while the n-BuOH fraction had more phenol contents. In the DPPH and ABTS assays, the MeOH extract showed a scavenging effect greater than that of the A+M extract (p<0.05). The n-BuOH fraction (0.5 mg/ml concentrations) showed scavenging effects of 72% and 92%, respectively, in the DPPH and ABTS assays (p<0.05). However, the 85% aq. MeOH fraction showed a 90% scavenging effect in the DPPH assay only. In 120 min ROS production assay, all tested fractions dose-dependently decreased cellular ROS production induced by H₂O₂ in comparison with that produced by exposure to the extract-free control. The MeOH extract showed a higher sinhibitory effect on cellular ROS producing than that of the A+M extract at all concentrations tested. Treatment with the n-BuOH fraction (0.1 mg/ml concentrations) inhibited cellular ROS production by 60%. These results indicate that the n-BuOH fraction of wine by-product extract inhibited cellular oxidation and may contain valuable bioactive compounds such as flavonoids and phenols.

• Development and Reproduction
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• v.10 no.4
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• pp.239-245
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• 2006

Experiments were conducted to determine the effects of beta-mercaptoethanol(${\beta}-ME$) supplements to the maturation medium on in vitro fertilization(IVF) and intracellular glutathione(GSH) concentration. Bovine cumulus-intact oocytes were matured in TCM-199 medium containing FBS, hormonal supplements, and ${\beta}-ME$(0, 25 and $50\;{\mu}M$) for 12h and 24 h. After culture, cumulus-free matured oocytes were co-incubated with frozen-thawed spermatozoa for 24h. Maturation rate increased(p<0.05) in ${\beta}-ME$ treatment group, but no significant differences among treatment groups. Also, increases(p<0.05) in intracellular GSH concentration before and after fertilization were observed in $50\;{\mu}M\;{\beta}-ME$ supplements to the maturation medium. Male pronuclear formations after IVF was increased(p<0.05) in ${\beta}-ME$ treatment group, but no significant difference among treatment groups. In conclusion, supplementing ${\beta}-ME$ into the maturation medium increased maturation rates, fertilization rates, and intracellular GSH concentrations.

• Journal of Korean Library and Information Science Society
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• v.52 no.1
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• pp.79-108
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• 2021

Information retrieval in the health field has several challenges. Health information terminology is difficult for consumers (laypeople) to understand. Formulating a query with professional terms is not easy for consumers because health-related terms are more familiar to health professionals. If health terms related to a query are automatically added, it would help consumers to find relevant information. The proposed query expansion (QE) models show how to expand a query using MeSH terms. The documents were represented by MeSH terms (i.e. Bag-of-MeSH), found in the full-text articles. And then the MeSH terms were used to generate LDA (Latent Dirichlet Analysis) topic models. A query and the top k retrieved documents were used to find MeSH terms as topic words related to the query. LDA topic words were filtered by threshold values of topic probability (TP) and word probability (WP). Threshold values were effective in an LDA model with a specific number of topics to increase IR performance in terms of infAP (inferred Average Precision) and infNDCG (inferred Normalized Discounted Cumulative Gain), which are common IR metrics for large data collections with incomplete judgments. The top k words were chosen by the word score based on (TP *WP) and retrieved document ranking in an LDA model with specific thresholds. The QE model with specific thresholds for TP and WP showed improved mean infAP and infNDCG scores in an LDA model, comparing with the baseline result.

• Korea Petroleum Association Journal
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• no.4 s.146
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• pp.51-58
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• 1993

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.10
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• pp.1430-1438
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• 2012

The present experiment was conducted to determine the digestible energy (DE), metabolizable energy (ME) content, and the apparent total tract digestibility (ATTD) of energy in growing pigs fed diets containing one of ten cottonseed meals (CSM) collected from different provinces of China and to develop in vitro prediction equations for DE and ME content from chemical composition of the CSM samples. Twelve growing barrows with an initial body weight of $35.2{\pm}1.7$ kg were allotted to two $6{\times}6$ Latin square designs, with six barrows and six periods and six diets for each. A corn-dehulled soybean meal diet was used as the basal diet, and the other ten diets were formulated with corn, dehulled soybean meal and 19.20% CSM. The DE, ME and ATTD of gross energy among different CSM sources varied largely and ranged from 1,856 to 2,730 kcal/kg dry matter (DM), 1,778 to 2,534 kcal/kg DM, and 42.08 to 60.47%, respectively. Several chemical parameters were identified to predict the DE and ME values of CSM, and the accuracy of prediction models were also tested. The best fit equations were: DE, kcal/kg DM = 670.14+31.12 CP+659.15 EE with $R^2$ = 0.82, RSD = 172.02, p<0.05; and ME, kcal/kg DM = 843.98+25.03 CP+673.97 EE with $R^2$ = 0.84, RSD = 144.79, p<0.05. These results indicate that DE, ME values and ATTD of gross energy varied substantially among different CSM sources, and that some prediction equations can be applied to predict DE and ME in CSM with an acceptable accuracy.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2955-2959
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• 2011

Second-order rate constants for nucleophilic substitution reactions of 2,4-dinitrophenyl benzenesulfonate 1a with a series of alicyclic secondary amines in MeCN have been measured spectrophotometrically and compared with those reported previously for the corresponding reactions performed in aqueous medium to investigate the effect of medium on reactivity and reaction mechanism. The amines employed in this study are found to be more reactive in the aprotic solvent than in $H_2O$. The reactions of 1a in MeCN result in a linear Br${\o}$nsted-type plot with ${\beta}_{nuc}$ = 0.58, which contrasts to the curved Br${\o}$nsted-type plot reported previously for the corresponding reactions performed in the aqueous medium (i.e., ${\beta}_2$ = 0.86 and ${\beta}_1$ = 0.38). Accordingly, it has been concluded that the reaction mechanism changes from a stepwise mechanism to a concerted pathway upon changing the medium from $H_2O$ to MeCN. Reactions of Y-substituted phenyl benzenesulfonates 1a-c with piperidine in MeCN result in a linear Br${\o}$nsted-type plot with ${\beta}_{lg}$ = -1.31, indicating that expulsion of the leaving group is significantly more advanced than bond formation in the transition state. The trigonal bipyramidal intermediate ($TBPy^{\pm}$) proposed previously for the reactions in $H_2O$ would be highly unstable in MeCN due to strong repulsion between the negative charge in $TBPy^{\pm}$ and the negative dipole end of MeCN. Thus, destabilization of $TBPy^{\pm}$ in MeCN has been concluded to change the reaction mechanism from a stepwise mechanism to a concerted pathway.