• Horticultural Science & Technology
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• v.19 no.2
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• pp.140-144
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• 2001

Field investigations were initiated to determine possible new 'ssam' vegetable that could be grown during the summer season in highland. Korean 'ssam' means cooked rice in vegetables. The 'ssam' vegetable is called that those leaves has been used for wrapping at meal. Seventeen leafy vegetables were studied, including chard (Beta vulgaris L. var. flavescens DC.), leaf broccoli (Brassica oleracea L. var. italica), Chinese leek (Allium tuberosum Rottl.), Japanese hornwort (Cryptotaenia japonica Hassk), red leaf mustard (Brassica juncea L.), green leaf mustard (Brassica juncea L.), leaf parsley (Petroselinum crispum Nijim), pakchoi (Brassica campestris L. ssp. chinensis Jusl.) tatsoi (Brassica campestris var. narisoma), kale (Brassica oleracea var. acephala), collard (Brassica oleracea var. acephala), Korean mint (Agastache rugosa O. Kuntze), romaine lettuce (Lactuca sativa L. var. longifolia Lam.), red leaf chicory (Cichorium intybus L. var. folisum), red chicory (Cichorium intybus L. var. folisum), green leaf chicory (Cichorium intybus L. var. folisum), and sprouting broccoli (Brassica oleracea L. var. italica). Date of the first harvest in 1999 was July 10th in chard, leaf broccoli, red mustard, mustard, leaf parsley, pakchoi, tatsoi, kale, collard, Korean mint, red leaf chicory, red chicory, green leaf chicory, and sprouting broccoli. Date of the first harvest for Chinese leek, Japanese hornwort, and romaine lettuce was from the middle of June to the late of August. Based on ratings on marketable yield, we found good leaf shape, taste and yield in chard, red leaf mustard, green leaf mustard, pakchoi, tatsoi, romaine lettuce, red leaf chicory, red chicory, and green leaf chicory. Even though the most of all these vegetables were obtained high scores by test panels in shape, taste and quality, but some of them revealed inadequate leaf size as a 'ssam' vegetable. That problem will be solved by control of harvesting time. On the basis of this observation, chard, red leaf mustard, green leaf mustard, pakchoi, tatsoi, romaine lettuce, red leaf chicory, red chicory, and green leaf chicory were rated as promising 'ssam' vegetable by analysis of profits, adaptation, and quality.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.1
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• pp.30-35
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• 2024

In order to improve the efficiency of the water splitting system for hydrogen production, the high overvoltage in the electrochemical reaction caused by the catalyst in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) must be reduced. Among them, transition metal-based compounds are attracting attention as catalyst materials that can replace precious metals such as platinum that are currently used. In this study, nickel foam, an inexpensive metal porous material, was used as a support, and Fe-doped β-Ni(OH)₂ microcrystals were synthesized through a hydrothermal synthesis process. In addition, in order to improve OER properties, changes in the shape, crystal structure, and water splitting characteristics of Fe-Mo co-doped β-Ni(OH)₂ microcrystals synthesized by co-doping with Mo were observed. The changes in the shape, crystal structure, and applicability as a catalyst for water splitting were examined.

• Journal of Pharmaceutical Investigation
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• v.38 no.4
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• pp.241-247
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• 2008

Paclitaxel is a taxane diterpene amide, which was first extracted from the stem bark of the western yew, Taxus brevifolia. This natural product has proven to be useful in the treatment of a variety of human neoplastic disorders, including ovarian cancer, breast and lung cancer. Paclitaxel is a highly hydrophobic drug that is poorly soluble in water. It is mainly given by intravenous administration. Therefore, The pharmaceutical formulation of paclitaxel ($Taxol^{(R)}$; Bristol-Myers Squibb) contains 50% $Cremophor^{(R)}$ EL and 50% dehydrated ethanol. However the ethanol/Cremophor EL vehicle required to solubilize paclitaxel in $Taxol^{(R)}$ has a pharmacological and pharmaceutical problems. To overcome these problems, new formulations for paclitaxel that do not require solubilization by $Cremophor^{(R)}$ EL are currently being developed. Therefore this study utilized a supercritical fluid antisolvent (SAS) process for cremophor-free formulation. To select hydrophilic polymers that require solubilization for paclitaxel, we evaluated polymers and the ratio of paclitaxel/polymers. HP-${\beta}$-CD was used as a hydrophilic polymer in the preparation of the paclitaxel solid dispersion. Although solubility of paclitaxel by polymers was increased, physical stability of solution after paclitaxel/polymer powder soluble in saline was unstable. To overcome this problem, we investigated the use of surfactants. At 1/20/40 of paclitaxel/hydrophilic polymer/ surfactant weight ratio, about 10 mg/mL of paclitaxel can be solubilized in this system. Compared with the solubility of paclitaxel in water ($1\;{\mu}g/mL$), the paclitaxel solid dispersion prepared by SAS process increased the solubility of paclitaxel by near 10,000 folds. The physicochemical properties was also evaluated. The particle size distribution, melting point and amophorization and shape of the powder particles were fully characterized by particle size distribution analyzer, DSC, SEM and XRD. In summary, through the SAS process, uniform nano-scale paclitaxel solid dispersion powders were obtained with excellent results compared with $Taxol^{(R)}$ for the physicochemical properties, solubility and pharmacokinetic behavior.

• CELLMED
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• v.6 no.4
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• pp.23.1-23.6
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• 2016

With the rapid developments in nanotechnology, an increasing number of nanomaterials have been applied in various aspects of our lives. Recently, pharmaceutical nanotechnology with numerous advantages has growingly attracted the attention of many researchers. Zinc oxide nanoparticles (ZnO-NPs) are nanomaterials that are widely used in many fields including diagnostics, therapeutics, drug-delivery systems, electronics, cosmetics, sunscreens, coatings, ceramic products, paints, and food additives, due to their magnetic, catalytic, semiconducting, anti-cancer, anti-bacterial, anti-inflammatory, ultraviolet-protective, and binding properties. The present review focused on the recent research works concerning role of ZnO-NP on inflammation. Several studies have reported that ZnO-NP induces inflammatory reaction through the generation of reactive oxygen species by oxidative stress and production of inflammatory cytokines by activation of nuclear factor-${\kappa}B$ ($NF-{\kappa}B$). Meanwhile, other researchers reported that ZnO-NP exhibits an anti-inflammatory effect by inhibiting the up-regulation of inflammatory cytokines and the activation of $NF-{\kappa}B$, caspase-1, $I{\kappa}B$ $kinase{\beta}$, receptor interacting protein2, and extracellular signal-regulated kinase. Previous studies reported that size and shape of nanoparticles, surfactants used for nanoparticles protection, medium, and experimental conditions can also affect cellular signal pathway. This review indicated that the anti-inflammatory effectiveness of ZnO-NP was determined by the nanoparticle size as well as various experimental conditions. Therefore, the author suggests that pharmaceutical therapy with the ZnO-NP is one of the possible strategies to overcome the inflammatory reactions. However, further studies should be performed to maximize the anti-inflammatory effect of ZnO-NP to apply as a potential agent in biomedical applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.388-388
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• 2010

In this study, Ferroelectric vinylidene fluoride-trifluoroethylene (VF2-TrFE) copolymer films were directly deposited on degenerated Si (n+, $0.002\;{\Omega}{\cdot}cm$) using by spin coating method. A 1~5 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene (VF2:TrFE = 70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers at a spin rate of 2000 ~ 4000 rpm for 2 ~ 30 seconds. After annealing in a vacuum ambient at 100 ~ $200^{\circ}C$ for 60 min, upper aluminum electrodes were deposited by vacuum evaporation for electrical measurement. X-ray diffraction results showed that the VF2-TrFE films on Si substrates had $\beta$-phase of copolymer structures. The capacitance on highly doped Si wafer showed hysteresis behavior like a butterfly shape and this result indicates clearly that the copolymer films have ferroelectric properties. The typical measured remnant polarization ($P_r$) and coercive filed ($E_c$) values were about $5.7\;{\mu}C/cm^2$ and 710 kV/em, respectively, in an applied electric field of ${\pm}$ 1.5 MV/em. The gate leakage current densities measured at room temperature was less than $7{\times}10^{-7}\; A/cm^2$ under a field of 1 MV/cm.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.48.3-49
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• 2017

Interplanetary space of the solar system contains a large number of dust particles, referred to as Interplanetary Dust Particles (IDPs) cloud complex. They are observable through meteors and zodiacal lights. The relative contribution of possible sources to the IDPs cloud complex was an controversial topic, however, recent research (Yang & Ishiguro, 2015 and references therein) suggested a dominance of cometary origin. In this study, we numerically investigated the orbital evolution of cometary dust particles, with special concerns on different evolutionary tracks and its consequences according to initial orbits, size and particle shape. The effect of dust particle density and initial size-frequency distribution (SFD) were not decisive in total cloud complex mass and mass supply rate, when these physical quantities are confined by observed zodiacal light brightness and dust particle SFD at 1 au. We noticed that, if we assume the existence of fluffy aggregates discovered in the Earth's stratosphere and the coma of 67P/Churyumov-Gerasimenko, the required mass supply rate decreases significantly. We also found out that close encounters with planets (mostly Jupiter) are the dominating factor of the orbital evolution of dust particles, as the result, the lifetime of cometary dust particles are shorter than Poynting-Robertson lifetime (around 250 thousand years). As another consequence of severe close encounters, only a small fraction of cometary dust particles can be transferred into the orbit < 1 au. This effect is significant for large size particles of ${\beta}$ < 0.01. The exceptional cases are dust particles ejected from 2P/Encke and active asteroids. Because they rarely encounter with Jupiter, most dust particles ejected from those objects are governed by Poynting-Robertson effect and well transferred into the orbits of small semimajor axis. In consideration of the above effects, we directly estimated probability of mutual collisions between dust particles and concluded that mutual collisions in the IDPs cloud complex is mostly ignorable, except for the case of large sized particles from active asteroids.

• The Plant Pathology Journal
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• v.25 no.2
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• pp.121-127
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• 2009

Since July 2005, survey of chestnut ink disease was carried out in chestnut stands located at southern parts of Korea. Dead chestnut trees showing inky ooze on necrotic trunks were found in two different locations. In order to isolate and identify the causal fungus, infected tissues and soil samples around dead or dying trees were collected and placed on Phytophthora-selective medium. Rhododendron and chestnut tree leaves were used as a bait to isolate the fungus from soil samples by attracting zoospores in soil suspensions. On V-8 culture medium, the isolates produced homothallic oogonia with protuberances ($34.0-46.2{\times}21.9-26.7{\mu}m$) abundantly, but did not produced sporangia. Mass production of sporangia was possible by immersing agar plugs with actively growing mycelium in the creek water at $18^{\circ}C$ for 3 days. Sporangia were papillate, and ovoid to obpyriform ($17.0-38.9{\times}14.6-29.2{\mu}m$) in shape. Comparison of the ITS sequences revealed that the isolates had 100% identity to the P. katsurae isolates from Japan and New Zealand and 99.6% identity to other P. katsurae isolates. All of the examined isolates from Korea were completely identical to each other in ITS sequence. Numerous sporangia were formed in filtered as well as unfiltered creek water, but no sporangia formed in sterilized distilled water. Light induced sporangia formation, but has no influence on oospore formation. Amendments of ${\beta}$-sitosterol in culture media have no significant effect on mycelial growth but significantly stimulate oospore and sporangia formation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.803-808
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• 2006

This paper was a study about noise reduction through flow stabilization in duel using experimental method and numerical analysis at the same time. To determine the fan's type three kinds of fans(axial fan, centrifugal fan, and axial fan with centrifugal type) was examined to investigate the suitability for duct. As a result, under the equal number of rotation 2000 RPM, performance of an axial fan with centrifugal type was the most superior by 55dBA at 4.3CMM among other fans. After this, analyzed the results of the numerical analysis to find out the optimum design of pitch angle such as $0^{\circ},\;10^{\circ},\;15^{\circ}\;and\;20^{\circ}$. The intensity of turbulence was low when pitch angle was $15^{\circ}$ and air volume became peak by 5.08 CMM. It was observed that axis component of velocity increased gradually when pitch angle increased from $0^{\circ}\;to\;20^{\circ}$. Finally, designed the shapes of D/S(Down Stream) in duct that agreed inlet angle($\delta$) of stationary blades with pitch angle($\beta$) of axial fan with centrifugal type and derived flow to duct medial, and changed the shape of motor-mount to reduce occurance of unstable vortex in tip of impeller, and embodied noise reduction and improvement of air flow rate through flow stabilization.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2000.04a
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• pp.150-156
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• 2000

Oligotrophic bacteria isolated from forest soil showed a specific community consisting of various taxonomic groups compared with those in other soil or aquatic habitats. Based on the cell shape, the isolates were divided into four groups: regular rod, curved/spiral rod, irregular rod, and prosthecate bacteria. The cellular fatty acids 60 oligotrophic isolates were analyzed. The 30 fatty acids which were identified or characterized are classified. At the dendrogram based on cellular fatty acid composition, four clusters(I-IV) were separated at a euclidian distance of about 50. Cluster 3 and 4-a strains were containing Q-8, these strains are accommodated in the Proteobacteria gamma and beta subdivision. The chemotaxonomic profiles of the cluster 4-a strains showed good agreement with those of the genus Burkholderia. Cluster 3 was characterized by the presence of branched-chain fatty acids, iso-C15:0, iso-C17:1, and iso-C17:0 as the major components. These chemotaxonomy suggested the close relationship of the isolates with Xathomonas/Sterotrophomonas group. Based on the 16S rDNA sequence analysis, the two representative strains(MH256 and MA828) of cluster 3 showed the close relation to genera, Xathomonas/Sterotrophomonas, but were not included in these genera. These strains were even further away from core Xanthomonas, and clearly were seen to branch outside the cluster formed by the Sterotrophomonas maltophilia. MH256 and MA828 16S rDNA sequence was different enough to put new genus on a separate branch. The isolates with Q-10 were also studied. They are corresponded to the two large groups in Proteobacteria alpha subdivision. One was incorporated in the genus Bradyrhizobium cluster, which also includes Agromonas, a genus for oligotrophic bacteria. The strains of the other group showed high similarity to the genus Agrobacterium.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.111-118
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• 2010

Reinforced steel corrosion due to concrete carbonation is one of main factors on the durability of RC structure. The carbonation velocity have an effect on carbon dioxide density, concrete quality and structural shape. Specially, these problems have increased in urban area. This study investigates the carbonation status of the bridges and quantifies the effect of carbonation based on various domestic field data. The failure probability of durability is evaluated on the basis of reliability concept. According to experimental results of the carbonation depth, the carbonation depth increased with structural age and carbonation velocity decreased with high strength of concrete. In most cases, the failure probability of durability by carbonation was more than 10%. Also, The results requires the minimum cover thickness of 70-80mm for target safety index(${\beta}$=1.3) proposed by Korean concrete specification.