• Korean Journal of Environment and Ecology
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• v.27 no.5
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• pp.550-560
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• 2013

This study was investigated the morphological characters, secondary sexual dimorphism, and habitat patterns of Korean Rattus animals collected on Jeju Island from April 2005 to October 2012. Two wild rat species, namely R. norvegicus and R. tanezumi were identified on Jeju Island based on morphological characteristics and molecular data; however, R. rattus, which had recorded formerly, was not found in this study. Individuals of R. norvegicus were captured from urban, rural, and natural habitats, while those of R. tanezumi were specially found in animal farms and the surrounding areas. Comparing of morphological characters of two species, R. norvegicus had a shorter tail and ears than R. tanezumi (p<0.05), and the ratios of tail length and ear length to those of head-body length showed significantly differences between two species (p<0.05). The body weights (BW) of urban populations of R. norvegicus were significantly heavier than those of rural populations (p<0.05). No secondary sexual dimorphism was found in R. norvegicus, but females of R. tanezumi showed heavier BW than those of males (p<0.05). These findings suggest that it is necessary to revise the records for the existence of R. tanezumi and to confirm the animal fauna and elucidate the distribution and ecological characteristics from further studies using extensive sampling and detailed investigations on Jeju Island and also on the Korean Peninsula.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.546-546
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• 2008

Copper (Cu) Chemical mechanical polishing (CMP) has been an essential process for Cu wifing of DRAM and NAND flash memory beyond 45nm. Copper has been employed as ideal material for interconnect and metal line due to the low resistivity and high resistant to electro-migration. Damascene process is currently used in conjunction with CMP in the fabrication of multi-level copper interconnects for advanced logic and memory devices. Cu CMP involves removal of material by the combination of chemical and mechanical action. Chemicals in slurry aid in material removal by modifying the surface film while abrasion between the particles, pad, and the modified film facilitates mechanical removal. In our research, we emphasized on the role of chemical effect of slurry on Cu CMP, especially on the effect of amine functional group on removal rate selectivity between Cu and Tantalum-nitride (TaN) film. We investigated the two different kinds of complexing agent both with amine functional group. On the one hand, Polyacrylamide as a polymer affected the stability of abrasive, viscosity of slurry and the corrosion current of copper film especially at high concentration. At higher concentration, the aggregation of abrasive particles was suppressed by the steric effect of PAM, thus showed higher fraction of small particle distribution. It also showed a fluctuation behavior of the viscosity of slurry at high shear rate due to transformation of polymer chain. Also, because of forming thick passivation layer on the surface of Cu film, the diffusion of oxidant to the Cu surface was inhibited; therefore, the corrosion current with 0.7wt% PAM was smaller than that without PAM. the polishing rate of Cu film slightly increased up to 0.3wt%, then decreased with increasing of PAM concentration. On the contrary, the polishing rate of TaN film was strongly suppressed and saturated with increasing of PAM concentration at 0.3wt%. We also studied the electrostatic interaction between abrasive particle and Cu/TaN film with different PAM concentration. On the other hand, amino-methyl-propanol (AMP) as a single molecule does not affect the stability, rheological and corrosion behavior of the slurry as the polymer PAM. The polishing behavior of TaN film and selectivity with AMP appeared the similar trend to the slurry with PAM. The polishing behavior of Cu film with AMP, however, was quite different with that of PAM. We assume this difference was originated from different compactness of surface passivation layer on the Cu film under the same concentration due to the different molecular weight of PAM and AMP.

• Journal of the Korean Chemical Society
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• v.62 no.4
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• pp.288-298
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• 2018

In this study, we surveyed pre- and post-perceptions of fourteen science teachers related to the atmosphere composition of molecules with different masses by the developed test. As a result of the test, the teachers were classified into two types of thoughts; One of them is considered the atmosphere to be a homogeneous solution, and the other is a thought that the composition ratio of the atmosphere was not homogeneous considering the different weights of particles. The two types were reclassified into three categories; one of them is considering large gravity effect, another is considering small gravity effect, and the other is considering medium scale gravity effect. Total six types of thoughts were found from the pre-test. After introducing crosscutting concepts which are related to the composition of atmosphere. The teachers discussed the phenomena with the molecular motion by weights of atoms and temperature, the homogeneity of the solution of air in chemistry domain. They also discussed with the relationship between mass and gravity and distance in physics domain. And the discussion included distribution of the atmosphere, convection phenomena, etc. After the discussion, the teachers changed their pre-conceptions to post-concoctions considering combined perspectives of gravity, mass, temperature, altitude etc. Through these changes, we are able to confirm the importance of crosscutting concepts covered in various disciplines. In the integrated science, we should help teachers to provide students with these types of thinking in order to form a coherent world-view and to carry out inquiry thinking as an intellectual tool.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.317-324
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• 2010

Metal-supported solid oxide fuel cells (SOFCs) have been developed to commercialize SOFCs. This new type of SOFC has high mechanical strength, but its mass transfer rate may be low due to the presence of a contact layer. In this study, the mass transfer characteristics of an anode-supported SOFC and a metal-supported SOFC are studied by performing numerical simulation. Governing equations, electrochemical reactions, and ceramic physical-property models are determined simultaneously; molecular diffusion and Knudsen diffusion are considered in mass transport analysis of porous media. The experimental results are compared with simulation data to validate the results of numerical simulation. The average current density of the metal-supported SOFC is 23% lower than that of the anode-supported SOFC. However, because of the presence of the contact layer, the metal-supported SOFC has a more uniform distribution than the anode-supported SOFC.

• Polymer(Korea)
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• v.27 no.1
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• pp.9-16
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• 2003

Ipriflavone (IP) stimulates proliferation and differentiation of osteoblast and also enhances calcitonin secretion in the presence of estrogen. Poly(lactide-co-glycolide) (PLCA) due to its controllable biodegradability and relatively good biocompatibility is one of the most significant candidates for the study of drug controlled release system. In this study, IP-loaded PLGA microspheres (MSs) was prepared by using conventional O/W solvent evaporation method. The size of MSs was in the range of 5~200 $mu extrm{m}$. The morphology of MSs was characterized by SEM. And, in vitro release amounts of IP were analyzed by HPLC. The highest encapsulation efficiency were obtained by using gelatin and polyvinyl alcohol (PVA) as emulsifiers. The morphology, size distribution, and in vitro release pattern of MSs were changed by several preparation parameters such as molecular weights (8, 20, 33 and 90 kg/mol), polymer concentrations (2.5, 5, 10 and 20%), emulsifier types (PVA, gelatin and Tween 80), initial drug loading amount (5, 10, 20 and 30%) and stirring speed (250, 500 and 1000 rpm). The release of IP in vitro was more prolonged over 30 days, with close to zero-order pattern by controlling the preparation parameters. The physicochemical properties of IP-loaded PLGA MSs were investigated by XRD and DSC.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.228-234
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• 1984

A partial hydrolysis of soybean protein isolate was carried out by using pepsin and trypsin. The degree of hydrolysis was evaluated by chemical analysis, viscometric measurements and gel electrophoresis. The functional properties of the hydrolyzates such as flow behavior, emulsion properties and foaming properties were evaluated. A selective hydrolysis of 11S protein fraction by pepsin was observed from the SDS-PAG electrophoresis. The changes in the molecular weight distribution by different conditions of enzyme hydrolysis were evaluated. The changes in the intrinsic viscosity of the protein hydrolylate by reaction time were highly correlated to the contents of TCA soluble protein and 0.03 M $CaCl_2$ soluble nitrogen. The degree of hydrolysis ($DH_{TCA}$, $DH_{Ca}$) were used to evaluate the effect of enzyme treatment on the functional properties of the hydrolyzate. The apparent viscosity and emulsion capacity and stability of the protein solution decreased as DH increased, while the foaming capacity increased linearly with the increasing DH.

• Korean Journal of Microbiology
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• v.54 no.2
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• pp.98-104
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• 2018

Naegleria fowleri and Acanthamoeba spp. are free-living amoebas that are widely distributed in natural environments. Although uncommon, infection with these protozoans can cause fatal disease in humans and animals. In this study, in order to select the appropriate method to survey Naegleria fowleri and Acanthamoeba spp. in water samples, four molecular biology techniques and one commercially available kit for real-time PCR were compared. The results indicated that the duplex real-time PCR was the most sensitive, and could be used to simultaneously detect two different free-living amoebas. Using the duplex real-time PCR approach, the two free-living amoebas were surveyed in three local streams in Daejeon, Republic of Korea. The concentrated free-living amoebas were inoculated onto non-nutrient agar plates which had been spread with heat-inactivated Escherichia coli and incubated for 5~7 days. After incubation, gDNA was extracted and used as the template for amplification by duplex real-time PCR. Acanthamoeba spp. and N. fowleri was detected from ten (83.3%) and two (16.6%) of the twelve samples, respectively. As these two free-living amoebas can be fatal, continuous surveillance is needed to track their distribution in the aquatic environment for the drinking water safety.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.6
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• pp.413-422
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• 2012

The purpose of this study is to investigated the mechanism of pharmacological action of local anesthetic and provide the basic information about the development of new effective local anesthetics. Fluorescent probe techniques were used to evaluate the effect of lidocaine HCl on the physical properties (transbilayer asymmetric lateral and rotational mobility, annular lipid fluidity and protein distribution) of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine cerebral cortex, and liposomes of total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. An experimental procedure was used based on selective quenching of 1,3-di(1-pyrenyl)propane (Py-3-Py) and 1,6-diphenyl-1,3,5-hexatriene (DPH) by trinitrophenyl groups, and radiationless energy transfer from the tryptophans of membrane proteins to Py-3-Py. Lidocaine HCl increased the bulk lateral and rotational mobility of neuronal and model membrane lipid bilayes, and had a greater fluidizing effect on the inner monolayer than the outer monolayer. Lidocaine HCl increased annular lipid fluidity in SPMV lipid bilayers. It also caused membrane proteins to cluster. The most important finding of this study is that there is far greater increase in annular lipid fluidity than that in lateral and rotational mobilities by lidocaine HCl. Lidocaine HCl alters the stereo or dynamics of the proteins in the lipid bilayers by combining with lipids, especially with the annular lipids. In conclusion, the present data suggest that lidocaine, in addition to its direct interaction with proteins, concurrently interacts with membrane lipids, fluidizing the membrane, and thus inducing conformational changes of proteins known to be intimately associated with membrane lipid.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.188-193
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• 1998

The authors examined the variations of environmental factors, the distributions of cyanobacteria, heterotrophic bacteria, and microorganisms that inhibit the growth of Anabaena cylindrica according to development and extinction of cyanobacterial bloom at a site in Daechung Dam reservoir. And certified the relationship between each other. Water temperature variated in a typical pattern. pH and concentrations of dissolved oxygen and chlorophylla was high in bloom period, and lowered with the decline of bloom. Phosphorus played as a growth-limiting factor at this study site. Total nitrogen concentration increased during blooming period, which indicated that nitrogen has been fixed by aquatic organisms such as cyanobacteria. Cyanobacteria distributed from June 17, and such cyanobacterial species as Anabaena spp., Aphanizomenon spp., Microcystis spp., Oscillatoria spp. and Phormidium spp. was detected during study period. Anabaena spp. distributed relatively highly distributed from July 23 to September 22, and disappeared completely at September 29. Heterotrophic bacterial and cyanobacterial populations varied inverse-proportionally. There was a relevancy between the variations of Anabaena spp., heterotrophic bacteria, and microorganisms that inhibit the growth of Anabaena cylindrica. Microorganisms that inhibit the growth of Anabaena cylindrica distributed from early growth phase of Anabaena spp. population to immediately after the extinction of Anabaena spp. With the population of Anabaena cylindrica growth-inhibiting microorganisms decreasing, increases of heterotrophic bacterial population followed it. Thease results indicate that microorganisms have a part in the extinction of cyanobacterial bloom, especially at its destroying period.

• Current Research on Agriculture and Life Sciences
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• v.32 no.3
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• pp.111-117
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• 2014

Phytophthora blight caused by Phytophthora capsici Leonian is a dangerous disease threatening pepper growers worldwide. The efficacy of chemical control is generally low as the pathogen is soil-borne and rapidly spread by zoospores during the rainy season. Thus, based on the demand for resistant varieties, various good resistant sources, such as CM334, AC2258, and PI201234, have been reported and their inheritance of resistance studied by many different authorities. However, the mode of inheritance remains unclear, as 1 or 2 independent dominant genes, 3 genes, or multiple genes have all been reported as responsible for resistance. Recently, QTL mappings of the gene factors for resistance have been reported, and molecular markers for resistance used in breeding programs. With the release of many resistant commercial hybrid cultivars, differentiation of pathotypes of the pathogen is attracting interest among breeders and plant pathologists. Various authorities have already classified the pathogen strains into different races according to the inter-action between resistant host plants, including the source of resistance, such as CM334 and PI201234, and resistant commercial varieties and P. capsici isolates. However, no standard differential host sets have yet been established, so the results are good only for the pathogen strains used in the experiments. Thus, for breeding varieties with durable resist-ance, it is important to introduce resistance from different sources and use diverse local pathogen strains collected in the target area for distribution in a breeding program.