• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1061-1070
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• 2023

Over the last few years, lead-free inorganic metal perovskites have gained impressive ground in empowering satellites in space exploration owing to their material stability and performance evolution under extreme space environments. The present work has examined the versatility of eight such perovskites as space radiation shielding materials by computing their photon, charged particles and neutron interaction parameters. Photon interaction parameters were calculated for a wide energy range using PAGEX software. The ranges of heavy charged particles (H, He, C, N, O, Ne, Mg, Si and Fe ions) in these perovskites were estimated using SRIM software in the energy range 1 keV-10 GeV, and that of electrons was computed using ESTAR NIST software in the energy range 0.01 MeV-1 GeV. Further, the macroscopic fast neutron removal cross-sections were also calculated to estimate the neutron shielding efficiencies. The examined shielding parameters of the perovskites varied depending on the radiation type and energy. Among the selected perovskites, Cs₂TiI₆ and Ba₂AgIO₆ displayed superior photon attenuation properties. A 3.5 cm thick Ba₂AgIO₆-based shield could reduce the incident radiation intensity to half its initial value, a thickness even lesser than that of Pb-glass. Besides, CsSnBr₃ and La_0.8Ca_0.2Ni_0.5Ti_0.5O₃ displayed the highest and lowest range values, respectively, for all heavy charged particles. Ba₂AgIO₆ showed electron stopping power (on par with Kovar) better than that of other examined materials. Interestingly, La_0.8Ca_0.2Ni_0.5Ti_0.5O₃ demonstrated neutron removal cross-section values greater than that of standard neutron shielding materials - aluminium and polyethylene. On the whole, the present study not only demonstrates the employment prospects of eco-friendly perovskites for shielding space radiations but also suggests future prospects for research in this direction.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1034-1042
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• 1996

Various $TiO_2-SiO_2$ composite powders were prepared by the modified sol-gel method using 1-dodecanol as DCCA (Dryng Control Chemical Additive ). Their characterizations were carried out and their photocatalytic catalysis was examined on the evolution reaction of hydrogen. The weight losses at $500^{\circ}C$ of only $TiO_2$ and $SiO_2$ powders were 33. 0wt% and 42.5wt%, respectively, and those of the $TiO_2/SiO_2$ powders ($TiO_2/SiO_2=25/75$, 50/50 and 75/25) were about $70.0{\pm}3.0wt%$. The released substances from the powders were almost organic matters. The as-prepared powders except only $TiO_2$ powder were amorphous. Transformation of anatase to rutil was hindered by $SiO_2$ component and the crystallinity of anatase was decreased with increasing $SiO_2$ contents. The as-prepared powders were bulky states. By heating at $600^{\circ}C$ for 1 hr $TiO_2-SiO_2$ powders ($TiO_2=100%$, $TiO_2/SiO_2=75/25,\;50/50$) showed agglomerates consisted of particles in submicron, but those of $TiO_2/SiO_2=25/75$ and $SiO_2=100%$ were still bulky states. Specific surface area of the powders heat-treated at $600^{\circ}C$ for 1hr was increased with $SiO_2$ concents and their pore sizes were also depended on $SiO_2$ contents. The photocatalytic activity of $TiO_2/SiO_2=75/25$ heat-treated at $600^{\circ}C$ for 1hr was 0.240mo1/h.g-cat as $H_2$ evolution rate. This value was about 2.0 times that of P-25(Degussa P-25) as a standard photocatalyst.

• BMB Reports
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• v.43 no.3
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• pp.212-218
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• 2010

Zinc finger-containing transcription factors are the largest single family of transcriptional regulators in mammals, which play an essential role in cell differentiation, cell proliferation, apoptosis, and neoplastic transformation. Here we have cloned a novel KRAB-related zinc finger gene, ZNF424, encoding a protein of 555aa. ZNF424 gene consisted of 4 exons and 3 introns, and mapped to chromosome 19p13.3. ZNF424 gene was ubiquitously expressed in human embryo tissues by Northern blot analysis. ZNF424 is conserved across species in evolution. Using a GFP-labeled ZNF424 protein, we demonstrate that ZNF424 localizes mostly in the nucleus. Transcriptional activity assays shows ZNF424 suppresses transcriptional activity of L8G5-luciferase. Overexpression of ZNF424 in HEK-293 cells inhibited the transcriptional activity of NFAT and p21, which may be silenced by siRNA. The results suggest that ZNF424 protein may act as a transcriptional repressor that suppresses NFAT and p21 pathway to mediate cellular functions.

• The Journal of the Petrological Society of Korea
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• v.23 no.3
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• pp.279-292
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• 2014

Nd isotopic compositions analyzed from the Phanerozoic granitoids of Korea are integrated and discussed. Variations in Nd isotopic compositions can be explained either by temporal trend or by regional differences. Among the three active periods, first two periods during the Permian-Triassic and Jurassic seem to show variations from rather high ${\varepsilon}_{Nd}(t)$ values at the beginning to lower ${\varepsilon}_{Nd}(t)$ values during the later stages. Such trends probably reflect melting of the subducting oceanic crust and producing magma with higher proportion of depleted mantle derived materials during the early stage of subduction process, and subsequent magmas with greater proportion of old continental crust with progress of subduction. However, the Cretaceous-Paleogene period of active magmatism displays higher ${\varepsilon}_{Nd}(t)$ values during the advanced stage of the igneous activities, which is opposite to the previous active periods. The other explanation is that such differences in ${\varepsilon}_{Nd}(t)$ reflect regional differences, based on the observations that such high-${\varepsilon}_{Nd}(t)$ granitoids distribute in the northeastern Gyeongbuk Province and Gyeongsang Basin. If this is the case, the regions with highr ${\varepsilon}_{Nd}(t)$ values may have distinct crustal evolution histories, e.g. younger average age. The choice between the two hypothesis could be made through further studies.

• Korean Journal of Plant Taxonomy
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• v.44 no.3
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• pp.202-207
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• 2014

Lonicera insularis Nakai (Caprifoliaceae) is Korean endemic plant that lives along the shore of Ulleungdo and Dokdo. The aim of this study is to construct a phylogenetic relationship within six species (L.maackii, L.chrysantha, L.subsessilis, L. harai, L. morrowii) of genus Lonicera L. and Wigela subsessilis as outgroup and intraspecific variation of L. insularis using chloroplast DNA five regions sequences. Sequence analysis revealed that both L. insularis and L. morrowii showed complete homologies in the intergenic regions of trnL-trnF, trnS-trnG, psbM-trnD and matK coding region. However, sequence in the petN-psbM intergenic region showed a single nucleotide difference between both species, thus we designated them as CP01 and CP02. The plants having CP01 are prevalent in the Ulleungdo and Dokdo, while L. insularis and L. morrowii from Ulleungdo and of Dokdo, and Japan have CP02. This confirmed the existence of two cp DNA lineages with different geographical distributions. We can infer the allopatric speciation by geographical barrier. The result will provide the important basal data to study speciation and specie evolution of ocean islands such as Ulleungdo and Dokdo.

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.399-408
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• 2014

Glutathione S-transferases (GSTs) are a superfamily of detoxification enzymes that primarily catalyze the nucleophilic addition of reduced glutathione to both endogenous and exogenous electrophiles. In this study, we isolated and characterized a full-length of alpha class GST cDNA from the abalone (Haliotis discus hannai). The abalone GST cDNA encodes a 223-amino acid polypeptide with a calculated molecular mass of 25.8 kDa and isoelectric point of 5.69. Multiple alignments and phylogenetic analysis with the deduced abalone GST protein revealed that it belongs to the alpha class GSTs and showed strong homology with disk abalone (Haliotis discus discus) putative alpha class GST. Abalone GST mRNA was ubiquitously detected in all tested tissues. GST mRNA expression was comparatively high in the mantle, gill, liver, and digestive duct, however, lowest in the hemocytes. Expression level of abalone GST mRNA in the mantle, gill, liver, and digestive duct was 182.7-fold, 114.8-fold, 4675.8-fold, 406.1-fold higher than in the hemocytes, respectively. Expression level of abalone GST mRNA in the liver was peaked at 6 h post-infection with Vibrio parahemolyticus and decreased at 12 h post-infection. While the expression level of abalone GST mRNA in the hemocytes was drastically increased at 3 h post-infection with Vibrio parahemolyticus. These results suggest that abalone GST is conserved through evolution and may play roles similar to its mammalian counterparts.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.78-84
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• 2004

In order Nuruk to improve the quality of millet wine, a traditional Jeju cereal wine, yeasts and molds were isolated from 35 kinds of Nuruk collected nationwide. Isolated strains were screened for saccharification of starch and brewing of millet wine. Fermentation characteristics of millet wine with different types of Nuruk were also investigated. The average number of microbial populations in the Nuruk were $6.4{\times}10^5{\sim}4.5{\times}10^7\;cfu/g$ for molds and $1.4{\times}10^4{\sim}7.7{\times}10^7\;cfu/g$ for yeasts. Among the 169 strains of molds and 103 strains of yeasts, 16 strains were screened for saccharifying activity on starch as a substrate, and one yeast strain was screened for the brewing of millet wine. A8-3, supposed as Aspergillus sp., showed the highest enzyme activities of glucdamylase, ${\alpha}-amylase$ and xylanase while B23-3 strain, supposed as Rhizopus sp., showed the highest saccharifying activity. A10-4, supposed as Saccharomyces sp., showed the highest level of weight loss from $CO_2$ evolution, sugar and alcohol tolerance during fermentation. When the Nuruk was made after inoculation with the selected strains, saccharifying activity was higher for the co-cultivation of A8-3 and B23-3 than individual cultivation of each strain. Similar saccharifying activities were shown in both disc-type and pellet-type Nuruk. It was suggested that pellet-type Nuruk could improve fermentation yield. The collected Nuruk consisted of $10{\sim}13%$ moisture, $55{\sim}70%$ total sugar, $10{\sim}18%$ crude protein, $0.2{\sim}1.0%$ crude fat and $1.8{\sim}2.1%$ ash. The Nuruk made in this study was composed of $12{\sim}15%$ moisture, $61{\sim}71%$ total sugar, $15{\sim}20%$ crude protein, $0.4{\sim}1.5%$ crude fat and $1.1{\sim}1.5%$ ash.

• Animal Systematics, Evolution and Diversity
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• v.5 no.1
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• pp.77-88
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• 1989

Genetic and morphometric comparison between two species of the genus Agkistrodon were performed to estimate the degree of genic variation and to clarify the taxonomic status of Cheju population, a suspected hybrid form between A. blomhoffii brevicaudus and A u ussuriensis. A sum of 147 specimens representing six populations of A.b. brevicaudus and two populations of A ussuriensis was used in this study. Out of the 21 loci examined, 5 loci (Adh, Ldh-2, Mdh-2, Mpi, Pgi) were monomorphic with identical mobility in both species. O Other Sioci (Aco, Gp, Fum, [po and Xdh in A b. brevicaudus; Est, Got-l, Gp, Mdh-l and 6Pgd in A ussuriensis) were highly poplymorphic. The degree of genic variation of Ab. b brevicaudus and A ussuriensis was A=1.SS, P=42.1%, HD=0.096, HG=O.l1S, and A= 1.4S, P = 31.6%, HD=0.117, HG =0.121, repectively. These values are twofold higher t than those of other reptilian species reported (Selander, 1976) including Korean species of Rhabdophis tigrina and Elaphe dione (Paik and Yang, 1986, 1987). The average values of t the genetic similarities among six populations of A b. brevicaudus and two populations of A ussuriensis were S=0.919 and S=0.962, respectively, whereas the value between species was S = 0.662. Presumed divergent time estimate (Nei, 1975) of these two species was about 1 1.8 million years ago. The analysis of the geographic variations of various morphological c characters was based on Gloyd’s criteria (Gloyd, 1972). Coloration of tongue and tail tip, t the number of ventral scales, and the number of subcaudal scales are good diagnostic c characters to identify these two species. The pattern of cross band is, however, highly variable within and between populations of both species. No hybrid was detected and the s suspected hybrid form of Cheju population falls within the range of A. ussuriensis in the g genetic and morphometric analyses.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.42.3-43
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• 2009

Triplets of identical cubesats will be built to carry out the following scientific objectives: i) multi-observations of ionospheric ENA (Energetic Neutral Atom) imaging, ii) ionospheric signature of suprathermal electrons and ions associated with auroral acceleration as well as electron microbursts, and iii) complementary measurements of magnetic fields for particle data. Each satellite, a cubesat for ion, neutral, electron, and magnetic fields (CINEMA), is equipped with a suprathermal electron, ion, neutral (STEIN) instrument and a 3-axis magnetometer of magnetoresistive sensors. TRIO is developed by three institutes: i) two CINEMA by Kyung Hee University (KHU) under the WCU program, ii) one CINEMA by UC Berkeley under the NSF support, and iii) three magnetometers by Imperial College, respectively. Multi-spacecraft observations in the STEIN instruments will provide i) stereo ENA imaging with a wide angle in local times, which are sensitive to the evolution of ring current phase space distributions, ii) suprathermal electron measurements with narrow spacings, which reveal the differential signature of accelerated electrons driven by Alfven waves and/or double layer formation in the ionosphere between the acceleration region and the aurora, and iii) suprathermal ion precipitation when the storm-time ring current appears. In addition, multi-spacecraft magnetic field measurements in low earth orbits will allow the tracking of the phase fronts of ULF waves, FTEs, and quasi-periodic reconnection events between ground-based magnetometer data and upstream satellite data.

• Korean journal of food and cookery science
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• v.26 no.5
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• pp.503-510
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• 2010

Different amounts of black garlic extract(0, 1, 3, 6, 9 and 12%(W/W)) were added to white pan bread, and the quality characteristics were evaluated. The pH and density of dough was decreased with increasing concentration of black garlic extract. There was no marked difference in the fermentation power of the dough expansion among the samples. The pH of bread decreased, and there were no significant differences in baking loss rate, dough yield or bread specific volume as the concentration of black garlic extract was increased. Regarding crust and crumb color values, lightness gradually diminished with increased amounts of black garlic extract in bread, whereas redness and yellowness increased. For measurement of texture, the highest hardness and gumminess of bread were observed in the 1% added group, and there was no remarkable difference between the 3% added group and control. Sensory evolution was the highest when 6% black garlic extract was added, but there were no significant differences in terms of color or overall acceptability. The results imply that addition of black garlic extract to white pan bread created a healthy and functional bread.