• Journal of Korea Water Resources Association
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• v.42 no.10
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• pp.845-855
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• 2009

In this study, changing characteristics of bed materials downstream of Daecheong Dam by flushing flow was investigated. Flushing flow affected the downstream environment in such a way that the mean diameter of bed material was increased and the standard deviation was decreased. The vertical sorting of bed materials composed of mixed sediment in the sediment box was observed. The surface layer was composed of gravels, and uniform sand material was buried below it. Relative fractions (Di/D50) of the bed material trapped in the box was nearly 1.0 for the bed material coarser than D$_{50}$ at Hyundo gauging station, and was between two values on the bed surface before and after the flushing flow at Bugang gauging station. Ratio of driving force to resisting force for each fraction ($\tau_i^*$) with the faction size maintained constant for the bed material coarser than D$_{50}$ at Hyundo station. At Bugang station, however, it was rapidly decreased. It means that pavement of the surface layer of bed material at Bugang station was developed, with the sediment particles moving downstream uniformly by flushing flow.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.275-281
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• 2020

Purpose: Development of a latent antimicrobial soft liner is strongly needed to overcome a possible inflammation related with its dimensional degrade or surface roughness. Modified tissue conditioner (TC) containing chitosan-doped silver nanoparticles (ChSN) complexes were synthesized and assessed for their characterizations. Materials and methods: ChSN were preliminarily synthesized from silver nitrate (AgNO₃), sodium borohydride (NaBH₄) as a reducing agent and chitosan biopolymer as a capping agent. Ultraviolet-visible and Fourier transform infrared spectroscopy were conducted to confirm the stable reduction of nanoparticles with chitosan. Modified TC blended with ChSN by 0 (control), 1.0, 3.0 and 5.0 % mass fraction were mechanically tested by ultimate tensile strength (UTS), silver ion elution and color stability (n=7). Results: At 24 hour and 7 day storage periods, UTS values were not significant (P>.05) as compared with pristine TC (control) and silver ion was detected with the dose-dependent values of ChSN incorporated. Color stability of TC were influenced by ChSN add, with the higher doses, the significantly greater color changes (P<.05). Conclusion: A stable synthesized ChSN was acquired and modified TC loading ChSN was characterized as silver ion releasing without detrimental physical property. For its clinical application, antimicrobial test, color control and multifactor investigations are still required.

• Journal of Aquaculture
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• v.6 no.3
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• pp.199-211
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• 1993

In order to elucidate the effect of dietary n-3 highly unsaturated fatty acids (n-3HUFA) on the changes of body weight and chemical compositions in the Korean rockfish during starvation, the fish were not fed for 9 weeks after fed different levels $(0\~1.5\%)$ of n-3 HUFA for 10 weeks. The higher level of n-3HUF A was contained in the diets, the slower body weight loss was resulted (P< 0.05). The decreasing rates of the body nutrients of the fish were significantly higher in the fish fed n-3HUF A deficient diets than those of the fish fed n-3 HUF A sufficient diets. Protein and lipid contents of the whole body were decreased with starvation whereas moisture content was increased. Decrease of lipid was mainly due to the decrease of nonpolar lipid. Amounts of polar lipid in the whole body were almost constant throughout the starvation, meaning not being affected by dietary n-3HUF A levels. Percentage of 22: 6n-3 was increased in the polar lipid fraction, but monoenic acids (16:1, 18:1), n-3 series (18:3, 18 4, 20:4) and n-6 series (20:2, 22:4, 22:5) were decreased with starvation. Fatty acid compositions of nonpolar lipid were not changed with starvation. These results suggest that all fatty acids of nonpolar lipid are equally utilized for energy during starvation.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.6
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• pp.37-44
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• 2019

This study was conducted to identify the distribution characteristics of small village wetlands in Geumsan County, an inland mountain zone, and comparing with Seocheon County, a coastal plain area with different ecological environment characteristics. Using Arc-GIS (v10.1) the village wetland code was extracted to derive the possible location of the village wetland, and the final distribution of the village was obtained by performing indoor judging work based on satellite images, aerial photographs, topographical maps, Korea Land Information System (KLIS), land use level, land cover degree (division), and land use status by local surveying and indoor analyzing. Although Geumsan County (576.66km2) is more than 60% larger than Seocheon County (358.04km2), 607 villages in Geumsan County and 570 villages in Seocheon County are capable of making similar levels of 106.5% of wetlands, but only a fraction of those in Seocheon County were found to be 67.6%. The density of the village wetlands was much lower than that of Seocheon County, a coastal plain area, because there were many mountainous areas in Geumsan County, and most of the wetlands temporarily created for water supply were removed during the analysis phase of the Jeongsa Image, so the actual wetlands of the village were judged to be only two-thirds different from those of Seocheon County.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1599-1605
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• 2002

In this study, three different experiments were conducted to evaluate the nutritional value of apple pomace produced in southern areas of the Republic of Korea (South Korea). The effects of combining apple pomace in different ratios with commercial concentrates and rice straw in the diets of Korean native goats (Capra hircus) were examined. In experiment I, in situ DM and CP disappearances from nylon bags incubated in the rumen of goats showed that greater amounts of DM and CP were released from apple pomace than those from concentrates at the later stages of incubation, but only after 48 h for DM and CP, respectively. This was reflected in the higher 'b' value of the slowly degradable fraction of the apple pomace compared to the concentrates. Prior to these times the trend was reversed. In experiment II, Korean native goats were fed a diet containing apple pomace with either rice straw or rice straw and concentrates, and the in vivo nutrient digestibilities compared to animals receiving an alfalfa hay. DM digestibility in the animals given apple pomace plus concentrates with rice straw (66.86%) were similar to the goats given alfalfa hay only (69.09%) but significantly greater than for a diet of rice straw plus concentrates. In experiment III, an in vivo study was conducted to investigate the inclusion of 30 to 60% apple pomace pre-mixed with rice straw, rice bran and concentrates on the nutritional value for Korean native goats. Apple pomace mixed diets had higher DM intakes, nutrient digestibility and nitrogen retention than diets without apple pomace, which may have been due to the higher non-structural carbohydrates (NSC) and less ADF and NDF than those in other treatments. Replacement of concentrates with apple pomace in rice straw based diets of Korean native goats fed either separately (experiment II) or by pre-mixing (experiment III) gave satisfactory feed intake, digestibility, pH of ruminal fluid and production of $NH_3$-N and VFA in the rumen of goats. The results of this study infer that apple pomace can be included at levels of up to 60% in the diets of goats without dramatic effect on the animal.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.93-107
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• 2013

Thermal conduction of the particulate composites or granular materials can be widely used in porous materials and geotechnical engineering. And it has continued to develop "effective thermal conductivity" of medium by modeling energy relationship among particles in medium. This study focuses on the development of the effective thermal conductivity at the unsaturated conditions of soils using the modified network model approach assisted by synthetic 3D random packed systems (DEM method, Discrete Element Method) at the particle scale. To verify the network model, three kinds of glass beads and the Jumunjin sand are used to obtain experimental values at various unsaturated conditions. The PPE (Pressure Plate Extractor) test is then performed to obtain SWCC (Soil-Water Characteristic Curve) of soil samples. In the modified network model, SWCC is used to adjust the equivalent radius of thermal cylinder at contact area between particles. And cutoff range parameter to define the effective zone is also adjusted according to the SWCC at given conditions. From a series of laboratory tests and the proposed network model, the modified network model which adopts a SWCC shows a good agreement in modeling thermal conductivity of granular soils at given conditions. And an empirical correlation between the fraction of the mean radius (${\chi}$) and thermal conductivity at given saturated condition is provided, which can be used to expect thermal conductivity of the granular soils, to estimate thermal conductivity of granular soils.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.189-194
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• 2012

We report a case of cardiac lymphoma in a 40-year-old man, who had a mediastinal mass which was diagnosed as sclerosing mediastinitis pathologically. The mediastinal mass caused right pulmonary arterial stenosis. The patient developed myocardial hypertrophy and echocardiography showed restrictive physiology and severely decreased left ventricle ejection fraction, 6 months later. MRI showed global left ventricular myocardial hypertrophy and diffuse late gadolinium hyperenhancement after administration of contrast material. Thus, non-ischemic cardiomyopathy was suspected on MRI. However, pathology confirmed the myocardial abnormality as lymphoma after myocardial biopsy. Because a basal part of the left ventricle and global subendocardial myocardium were not involved on contrast-enhanced delayed MRI, the MRI abnormalities could be differentiated from amyloidosis and other myocardial diseases. The peculiar non-mass forming diffuse hypertrophy pattern of cardiac lymphoma has not been known in the MRI literature.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.758-766
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• 2015

Dextran is a generic term for a bacterial exopolysaccharide synthesized from sucrose and composed of chains of D-glucose units connected by ${\alpha}$-1,6-linkages by using dextransucrases. Dextran could be used as vicosifying, stabilizing, emulsifying, gelling, bulking, dietary fiber, prebiotics, and water holding agents. We isolated new strain capable of producing dextran from Korean traditional kimchi and identified as Leuconostoc sp. strain JYY4. Batch fermentation was conducted in bioreactor with a working volume of 3 L. The media was MMY and 15% (w/v) sucrose. Mineral medium consisted of $3.0g\;KH_2PO_4$, $0.01g\;FeSO_4$, $H_2O$, $0.01g\;MnSO_4$, $4H_2O$, $0.2g\;MgSO_4\;7H_2O$, 0.01 g NaCl, $0.05g\;CaCl_2$ per 1 liter deionized water. The pH of media was initially adjusted to 6.0. The inoculation rate was 1.0% (v/v) of the working volume. Temperature was maintained at $28^{\circ}C$. The agitation rate was 100 rpm. The production pattern of dextran was associated with the cell growth. After 24 hr dextran reached its highest concentration of 59.4 g/L. The sucrose was consumed completely after 40 hr. Growth reached stationery phase when sucrose became limiting, regardless of the presence of fructose or mannitol. When the specific growth rate was 0.54 hr-1, utilization averaged 5.8 g/L-hr. The yield and productivity of dextran were 80% and 2.0 g/L-hr, respectively. Dextrans produced by were separated to two different size by an alcohol fraction method. The size of high molecular weight dextran (45% alcohol, v/v), less soluble dextran, was between MW 500,000 and 2,000,000. Soluble dextran (55% alcohol, v/v) was between 70,000 and 150,000. The molecular weight average of total dextran (70% alcohol, v/v) was between 150,000 to 500,000. The enzymatic hydrolyzates of total dextran of ATCC 13146 showed branched dextrans by Penicillium dextranase contained of glucose, isomaltose, isomaltotriose, and isomaltooligosaccharides greater than DP4 (degree of polymerization) that had branch points. Compounds greater than DP4 were branched isomaltooligosaacharides. Hydrolysates by the Lipomyces dextranase produced the same composition of oligosaccharides as those by Penicillin dextranase.

• Ocean and Polar Research
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• v.31 no.1
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• pp.121-131
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• 2009

In an effort to better understand the physiological and ecological differences between warm and cold water copepod species in Korean waters using lipid contents and compositions, two species of copepods (Pleuromamma sp. as a warm water species and Neocalanus plumchrus as a cold water species) were collected from the Northwest Pacific and East Sea/Sea of Japan, respectively. The cold water species showed two fold higher lipid contents than the warm water species (11% vs. 5% of dry weight). Wax esters, known as one of the major storage lipid classes, were found to be the dominant lipid class (accounting for 64% of total lipids) in the cold water species, whereas, in the warm water species, phospholipids, which are known as membrane components, were the dominant lipid class (accounting for 43% of total lipids),with a trace amount of the storage lipids as a form of triacylglycerols (${\leq}1%$ of total lipids). With regard to the fatty acid compositions, saturated fatty acids (SAFA), especially 16:0 (about 30% of total fatty acids), were most abundant in the warm water species, whereas the polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA : 20:5(n-3)) (${\geq}16%$ of total fatty acids), were most abundant in the cold water species. Among the neutral fraction of lipids, phytol, originating from the side chain of chlorophyll and indicative of active feeding on phytoplankton, was detected only in the warm water species. Significant quantities of fatty alcohols were detected in cold water species, particularly long-chain monounsaturated fatty alcohols (i.e. 20:1(n-9) and 22:1(n-11)), which are well known to abound in cold water herbivorous copepods. However, only trace amounts of short-chain fatty alcohols were detected in the warm water species. Twelve different kinds of sterols were detected in these copepod species, with cholest-5-en-$3{\beta}$-ol (cholesterol) and cholesta-5, 24-dien-$3{\beta}$-ol (desmosterol) dominating in cold and warm water species, respectively. In addition, for the warm water species (Pleuromamma sp.), we assessed the latitudinal gradients of lipid contents and compositions using samples from three different latitudinal regions (Philippine EEZ, Japan EEZ, and the East China Sea). Although no latitudinal gradients of lipid contents were detected, the lipid compositions, particularly dietary fatty acid markers, varied significantly with the latitude. The findings of this study confirm that the distribution of lipid contents and compositions in copepods may not only indicate their nutritional condition and diet history, but may also provide insights into their living strategies under different environmental conditions (i.e., water temperature, food availability).

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.668-680
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• 2020

Bacillus velezensis is an important plant growth-promoting rhizobacterium with immense potential in agriculture development. In the present study, Bacillus velezensis Lle-9 was isolated from the bulbs of Lilium leucanthum. The isolated strain showed antifungal activities against plant pathogens like Botryosphaeria dothidea, Fusarium oxysporum, Botrytis cinerea and Fusarium fujikuroi. The highest percentage of growth inhibition i.e., 68.56±2.35% was observed against Fusarium oxysporum followed by 63.12 ± 2.83%, 61.67 ± 3.39% and 55.82 ± 2.76% against Botrytis cinerea, Botryosphaeria dothidea, and Fusarium fujikuroi, respectively. The ethyl acetate fraction revealed a number of bioactive compounds and several were identified as antimicrobial agents such as diketopiperazines, cyclo-peptides, linear peptides, latrunculin A, 5α-hydroxy-6-ketocholesterol, (R)-S-lactoylglutathione, triamterene, rubiadin, moxifloxacin, 9-hydroxy-5Z,7E,11Z,14Z-eicosatetraenoic acid, D-erythro-C18-Sphingosine, citrinin, and 2-arachidonoyllysophosphatidylcholine. The presence of these antimicrobial compounds in the bacterial culture might have contributed to the antifungal activities of the isolated B. velezensis Lle-9. The strain showed plant growth-promoting traits such as production of organic acids, ACC deaminase, indole-3-acetic acid (IAA), siderophores, and nitrogen fixation and phosphate solubilization. IAA production was accelerated with application of exogenous tryptophan concentrations in the medium. Further, the lily plants upon inoculation with Lle-9 exhibited improved vegetative growth, more flowering shoots and longer roots than control plants under greenhouse condition. The isolated B. velezensis strain Lle-9 possessed broad-spectrum antifungal activities and multiple plant growth-promoting traits and thus may play an important role in promoting sustainable agriculture. This strain could be developed and applied in field experiments in order to promote plant growth and control disease pathogens.