• Journal of Radiation Protection and Research
• /
• v.18 no.2
• /
• pp.1-16
• /
• 1993

As guides to decision-making in the management of the victims in case of acute whole body or partial body radiation exposure, we studied the relationship between radiation dose and the frequency of chromosomal aberrations observed in peripheral lymphocytes that were irradiated in vitro with $^{60}Co\;{\gamma}-rays$ at doses ranging from 2Gy to 12Gy. The yields of cells with unstable chromosomal aberrations (dicentric chromosomes, ring chromosomes, and acentric fragment pairs) were 32% at 2Gy, 47% at 4Gy, 80% at 6Gy, 94% at 8Gy, and 100% at 10Gy and over. Ydr, which reflect average dose to the whole body in case of acute whole body exposure, were 1.373 at 2Gy, 0.669 at 4Gy, 1.734 at 6Gy, 2.773 at 8Gy, 3.746 at 10Gy and 5.454 at 12Gy. The relationship between radiation dose (D) and the frequency of dicentric plus ring chromosomes per cell(Ydr) could be expressed as $Ydr=9.322{\times}10^{-2}/Gy {\times}D+2.975{\times}10^{-2}/Gy^2{\times}D^2$. Qdr, which are used in estimating dose of partial body exposure and dose of past exposure, were 1.166 at 2Gy, 1.436 at 4Gy, 2.173 at 6Gy, 2.945 at 8Gy, 3.746 at 10Gy and 5.454 at 12Gy. To see how confidently this dosimetry system may be used, we obtained Qdr values from those who received one fraction of homogenous partial body irradiation of 1.BGy, 2.5Gy, and 7.OGy therapeutically; in vivo Qdr values were 1.109, 1.222 and 2.222 respectively. The estimated doses calculated from these in vivo Qdr values using the equation $Qdr=Ydr/(1- e^{-Ydr})$ were 1.52Gy, 2.48Gy, and 6.54Gy respectively, which were very close to the doses actually given.

• Journal of The Korean Association For Science Education
• /
• v.35 no.1
• /
• pp.37-52
• /
• 2015

In this study, assessment items to examine geocognition on plate tectonics were developed and applied to middle and high school students and college students. Conceptual constructs on plate tectonics are Earth interior structure, specific geomorphology, and geologic phenomena at each plate boundary. Construct for geocognition included temporal reasoning, spatial reasoning, retrospective reasoning, and system thinking. Pictorial data in each item were all obtained from GeoMapApp. Students' responses to the items were analyzed and measured cross-sectionally by Rasch model, which distinguishes persons' ability levels based on their scores for all items and compared them with item difficulty. By Rasch model analysis, Wright maps for middle and high school students and college students were obtained and compared with each other. Differential Item Functioning analysis was also implemented to compare students' item responses across school grades. The results showed: 1) Geocognition on plate tectonics was an assessable construct for middle and high school students in current science curriculum, 2) The most distinguished geocognition factor was spatial reasoning based on cross sectional analysis across school grades, 3) Geocognition on plate tectonics could be developed towards more sophisticated level through scaffolding of relevant instruction and earth science content knowledge, and 4) Geocognition was not a general reasoning separated from a task content but a content-specific reasoning related to the content of an assessment item. We proposed several suggestions for learning progressions for plate tectonics and national curriculum development based on the results of the study.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.37 no.2
• /
• pp.143-152
• /
• 2011

In this study, the antioxidative activity, inhibitory effects on tyrosinase and elastase, and active components of Quercus salicina Blume extracts were investigated. Q. salicina Blume was extracted using 50 % ethanol, from which ethyl acetate and aglycone fractions were prepared. The DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity ($FSC_{50}$) of Q. salicina Blume aglycone fraction was the highest ($8.25\;{\mu}g$/mL). The luminol-dependent chemiluminescence assay showed that reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of Q. salicina Blume aglycone fraction on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system was the most prominent at $0.039\;{\mu}g$/mL. The protective effects of extract/fractions of Q. salicina Blume against the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner ($1{\sim} 25\;{\mu}g$/mL). Especially, ${\tau}_{50}$ of aglycone fraction in $10 \;{\mu}g$/mL concentration showed the most protective effect at 259.9 min. The inhibitory effects ($IC_{50}$) on tyrosinase and elastase of Q. salicina Blume extracts were higher at aglycone fraction (respectively, $21.82 \;{\mu}g$/mL, $41.18\;{\mu}g$/mL). Active component analysis by TLC and HPLC showed quercetin, keampferol, catechin, quercitrin, isoquercitrin, hyperoside, and etc. These results indicate that Q. salicina Blume extract has strong antioxidative activity and can be used as antioxidant. Particularly, aglycone fraction of Q. salicina Blume showed superior antioxdative activity and high inhibitory effect on tyrosinase and elastase. Therefore, aglycone fraction of Q. salicina Blume could be applicable to new functional cosmetics.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.34 no.1
• /
• pp.25-35
• /
• 2008

In this study, the antioxidative effects and inhibitory effects on elastase and tyrosinase of Geranium nepalense extracts were investigated. The free radical(1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities ($FSC_{50}$) of extract/fractions of Geranium nepalense were in the order: 50% ethanol extract(15.0 ${\mu}g/mL$)${\mu}g/mL$). ${\mu}g/mL$). Reactive oxygen species (ROS) scavenging activities($OSC_{50}$) of some Geranium nepalense extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescense assay. The order of ROS scavenging activities were 50% ethanol extract($OSC_{50},\;0.23{\mu}g/mL$)${\mu}g/mL$)${\mu}g/mL$). Deglycosylated flavonoid fraction showed the most prominent scavenging activity. The protective effects of extract/fractions of Geranium nepalense on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Geranium nepalense extracts suppressed photohemolysis in a concentration dependent manner, particularly deglycosylated flavonoid fraction exhibited the most prominent celluar protective effect (${\tau}_{50}$, 676.7 min at 50 ${\mu}g/mL$). The inhibitory effect of aglycone fraction on tyrosinase($IC_{50}$, 70.0 ${\mu}g/mL$) and elastase ($IC_{50}$, 19.9 ${\mu}g/mL$) was very high. Aglycone fractions obtained from the deglycosylation reaction of ethyl-acetate fraction among the Geranium nepalense extracts, showed 2 bands in TLC and 2 peaks in HPLC experiments (370 nm). Two components were identified as quercetin(composition ratio, 15.3%), kaempferol(82.8%). These results indicate that extract/fractions of Geranium nepalense can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And component analysis of Geranium nepalense extract and inhibitory activity on elastase of the aglycone fraction could be applicable to new functional cosmetics for smoothing wrinkles.

• Korean Journal of Plant Resources
• /
• v.25 no.5
• /
• pp.568-577
• /
• 2012

The objective of this study was to investigate the antioxidative capacity of ethanol extracts from Rumex crispus L. The concentration of R. crispus L. extract at which DPPH radical scavenging activity was inhibited by 50% was 2.15 mg/mL, which was lower than that of ${\alpha}$-tocopherol (0.43 mg/mL), as compared to 100% by pyrogallol as a reference. Total antioxidant status was examined by total antioxidant capacity against ABTS radical reactions. Total antioxidant capacities of R. crispus L. extract at concentrations of 0.1 and 1 mg/mL were 0.47 and 2.33 mM Trolox equivalents, respectively, which were higher than those of ${\alpha}$-tocopherol. Superoxide scavenging activities of R. crispus L. extract at concentrations of 0.1 and 1 mg/mL were 21.5 and 78.9%, respectively, which were not significantly (p>0.05) different from those of catechin. Oxygen radical absorbance capacities of R. crispus L. extract at concentrations of 20 and 100 ${\mu}g/mL$ were 62.5 and 156.4 ${\mu}M$ Trolox equivalents, respectively, which were lower than those of ascorbic acid. Cupric reducing antioxidant capacities of R. crispus L. extract at concentrations of 0.1 and 1 mg/mL were 0.28 and 1.88 mM Trolox equivalents, which were similar or significantly (p<0.05) higher than those of ${\alpha}$-tocopherol, respectively. R. crispus L. extract prevented supercoiled DNA strand breakage induced by hydroxyl radical and peroxyl radical. Total phenolic contents of R. crispus L. extract at concentrations of 0.5 and 5 mg/mL were 0.58 and 3.85 mM gallic acid equivalents, respectively. R. crispus L. extract at concentration of 0.1 and 0.5 mg/mL inhibited 0.2 mM tert-butyl hydroperoxide-induced cytotoxicity by 38.5 and 63.5%, respectively, in HepG2 cell culture system. Thus, strong antioxidant and cytotoxicity-inhibiting effects of R. crispus L. extract seem to be due to, at least in part, the prevention from free radicals-induced oxidation as well as high levels in total phenolic contents.

• Korean Journal of Plant Resources
• /
• v.25 no.1
• /
• pp.156-168
• /
• 2012

Chrysanthemum is a cut flower species that normally lasts for 1 to 2 weeks, in some cases 3-4 weeks. This has been attributed to low ethylene production during senescence. Reduction in cut flower quality has been attributed to the formation of air embolisms that partially or completely blocks the water transport from the vase solution to the rest of the cut flower stem, increasing hydraulic resistance which may cause severe water stress, yellowing, wilting of leaf, and chlorophyll degradation. Standard type chrysanthemum can be harvested when buds were still tightly closed and then fully opened with the simple bud-opening solution. Standard type chrysanthemum can also be harvested when the minimum size of the inflorescence is about 5-6 cm bud which opened into the first flower full-sized flower. While spray varieties can be harvested when 2-4 most mature flowers have opened (40% opening). Cut flowers are sorted by stem length, weight, condition, and so on. Standard chrysanthemum is 80 cm length for standard type and 70cm for spray type. Pre-treatment with a STS, plant regulator such as GA, BA, 1-MCP, chrysal, germicide, and sucrose, significantly improved the vase life and quality of cut flowers. It is well established that vase solutions containing sugar can improve the vase life of cut chrysanthemum. Chrysanthemum is normally packed in standard horizontal fiberboard boxes. Chrysanthemum should normally be stored at $5{\sim}7^{\circ}C$. Precooling resulted in reduction in respiration, decomposition, and transpiration activities as well as decoloration retardation. There was significant difference between "wet" storage in 3 weeks and "dry" storage in 2 weeks. In separate pulsing solution trials, various germicides were tested, as well as PGRs to maintain the green color of leaves and turgidity. Prolonging vase life was attained with the application of optimal solution such as HQS, $AgNO_3$, GA, BA and sucrose. This also retarded senescence in leaves of cut flower stems. Fresh cut chrysanthemum can be transported using a refrigerated van with $5{\sim}7^{\circ}C$. Increasing consumption and usage of cut chrysanthemum of various cultivars would require efficient transport system, and effective information exchange among producer, wholesaler, and consumer.

• Korean Journal of Food Science and Technology
• /
• v.11 no.4
• /
• pp.242-248
• /
• 1979

To detect proper lytic assay conditions of the crude zumolyase from Arthrobacter luteus, effets of the various factors involved in the lytic system of Sacchromyces sake cultured with shaking in the malt extracts medium were investigated. The results are summarized as follows : 1. The susceptibilities of viable cells of S. sake from logarithmic growth phase to the lytic enzmye were much greater than those of the cells in lag and stationary phases. The cells cultured for 18 hr were the most susceptible to the enzyme. 2. Lytic activity of the enzyme toward the viable cells of S. sake was very low. It was, however, enhanced 4 folds of more by the pretreatment of the cells with 0.05 M sodium sulfite. 3. Lytic activity of the enzyme toward commercial baker's yeast cells was negligible, and the effect of sodium sulfite on the lysis of the cells also was nothing but a little. 4. The lyophilized cells of the baker's yeast showed more susceptibility to the lytic enzyme than viable cells of the yeast. No definite effect of sodium sulfite on the lysis of the lyophilized cells, however, was observed either baker's yeast of S. sake. 5. It appeared that the relationship between the reaction rate and the enzyme concentration on the lysis of the yeast cell walls followed enzyme kinetic theory, but one between the reaction rate and concentration of the yeast cells as substrates showed different pattern from that in enzyme kinetic theory. 6. After the preparation of crude zymolyase was kept at $7^[\circ}C$ for 10 days in the 0.05 M phosphate buffer, pH 7.5, the remainning lytic activity was about 80 %.

• Korean Journal of Food Science and Technology
• /
• v.44 no.6
• /
• pp.686-691
• /
• 2012

The objective of this research is to present method development and validation for the simultaneous determination of lutein and zeaxanthin using ultra performance liquid chromatography (UPLC). Also, rapid quantification was performed on six green leafy vegetables (Allium tuberosum, Aster scaber, Hemerocallis fulva, Pimpinella brachycarpa, Sedum sarmentosum and Spinacia oleracea) that are commonly consumed in Korea. Separation and quantification were successfully achieved with a Waters Acquity BEH C18 ($50{\times}2.1mm$, $1.7{\mu}m$) column by 85% methanol within 5 min. Two compounds showed good linearity ($r^2$ > 0.9968) in $1-150{\mu}g/mL$. Limit of detection (LOD) and quantification (LOQ) for lutein and zeaxanthin were 1.7 and 5.1 g/mL and 2.1 and 6.3 g/mL, respectively. The RSD for intra- and inter-day precision of each compound was less than 10.69%. The recovery of each compound was in the range of 91.75-105.13%. Aster scaber and Spinacia oleracea contained significantly higher amounts of lutein ($4.06{\pm}0.24$ and $3.97{\pm}0.10mg$/100 g of fresh weight), respectively.

• Journal of Life Science
• /
• v.21 no.12
• /
• pp.1678-1688
• /
• 2011

The apoptogenic effect of p-coumaric acid, a phenolic acid found in various edible plants, on human acute leukemia Jurkat T cells was investigated. Exposure of Jurkat T cells to p-coumaric acid (50-$150{\mu}M$) caused cytotoxicity and TdT-mediated dUTP nick-end labeling (TUNEL)-positive apoptotic DNA fragmentation along with Bak activation, ${\Delta}{\psi}m$ loss, activation of caspase-9, -3, -7, and -8, and PARP degradation in a dose-dependent manner. However,these apoptotic events were completely abrogated in Jurkat T cells overexpressing Bcl-2.Under these conditions, necrosis was not accompanied. Pretreatment of the cells with the pan-caspase inhibitor (z-VAD-fmk) could prevent p-coumaric acid-induced sub-$G_1$ peak representing apoptotic cells, whereas it failed to block ${\Delta}{\psi}m$ loss, indicating that the activation of caspase cascade was prerequisite for p-coumaric acid-induced apoptosis as a downstream event of ${\Delta}{\psi}m$ loss. FADD- and caspase-8-positive wild-type Jurkat T cell clone A3, FADD-deficient Jurkat T cell clone I2.1, and caspase-8-deficient Jurkat T cell clone I9.2 exhibited similar susceptibilities to the cytotoxicity of p-coumaric acid, excluding an involvement of Fas/FasL system in triggering the apoptosis. The apoptogenic activity of p-coumaric acid is more potent in malignant Jurkat T cells than in normal human peripheral T cells. Together, these results demonstrated that p-coumaric acid-induced apoptogenic activity in Jurkat T cellswas mediated by Bak activation, ${\Delta}{\psi}m$ loss, and subsequent activation of multiple caspases such as caspase-9, -3, -7, and-8, and PARP degradation, which could be regulated by anti-apoptotic protein Bcl-2.

• Journal of Life Science
• /
• v.22 no.12
• /
• pp.1644-1650
• /
• 2012

The aim of this study was to screen the polymorphisms and distribution of each genotype of insertion/ deletion (indel) markers which were found in a preliminary comparative study of bovine genomic sequence databases. Comparative bioinformatic analyses were first performed between the nucleotide sequences of Bovine Genome Project and those of expressed sequence tag (EST) database, and a total of fifty-one species of indel markers were screened. Of these, forty-two indel markers were evaluated, and nine informative indel markers were ultimately selected for population analysis. Nucleotide sequences of each marker were re-sequenced and their polymorphic patterns were typed in six cattle breeds: Holstein, Angus, Charolais, Hereford, and two Korean native cattle breeds (Hanwoo and Jeju Black cattle). Cattle breeds tested in this study showed polymorphic patterns in eight indel markers but not in the Indel-15 marker in Charolais and Holstein. The results of analysis for Jeju Black cattle (JBC) population indicated an observed heterozygosity (Ho) that was highest in HW_G1 (0.600) and the lowest in Indel_29 (0.274). The PIC value was the highest in HW_G4 (0.373) and lowest in Indel_6 (0.305). These polymorphic indel markers will be useful in supplying genetic information for parentage tests and traceability and to develop a molecular breeding system for improvement of animal production in cattle breeds as well as in the JBC population.