• Journal of the Economic Geographical Society of Korea
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• v.15 no.1
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• pp.26-41
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• 2012

This study investigates the time-space characteristics of intra-urban passenger flows in the Metropolitan Seoul area. In particular, we analyze the relationships between transit ridership and land use through the use of the subway passenger flow data obtained from the transit transaction databases. For this purpose, the strength of each subway station, i.e., the number of total in-coming and out-going passengers at each station, in the morning, afternoon, and evening, is calculated and visualized, which reflects urban land use patterns. Then the subway stations are classified into four groups via a hierarchical analysis of the in-coming and out-going passenger flows at 353 stations. Each group appears to have characteristic properties according to the region, e.g., residential areas and central business districts. This has been confirmed by the analysis which probes explicitly the relationship between the local socio-economic variables and station groups. This analysis, disclosing the inter-relationship between the subway network and urban land use, may be useful at various stages in urban as well as transportation planning, and provides analytical tools for a wide spectrum of applications ranging from impact evaluation to decision-making and planning support.

• The Korean Journal of Malacology
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• v.20 no.1
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• pp.55-63
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• 2004

Gonadosomatic index, condition index and reproductive cycle with the gonadal development of the female Octopus ocellatus were investigated by histological observations and morphometric data, from January to December, 2000. And changes in biochemical components of the ovary and the trunk tissues including the digestive organ associated with gonadal development were studied by biochemical analysis from January to October, 2001. The specimens were collected at the coastal waters of Buan, Jeollabuk-do, Korea, from January 2000 to October 2001. O. ocellatus is a dioecious organism. The gonad of O. ocellatus locates medially in posterior region of the body. Morphology of the ovary shows round and oval in shape, the average diameter and external colour of ripe ovary was 32 mm and semitransparent light brown in colour. As the ovary was getting mature, transparent elongated eggs covered with chorion were present in the ovarian cavity. Monthly changes in the gonadosomatic index (GSI) showed a similar pattern with those of the condition index. The GSI and condition index began to increase in March and reached the maximum in April. And then, their values decreased from May and reached the minimum in September. Reproductive cycle of O. ocellatus can be categorized into five successive stages: early developing stage (September to December), late developing stage (November to March), ripe stage (March to May), partially spawned stage (April to June), and degenerative/resting stage (June to October). Follicle cells attached to an oocyte were involved in vitellogenesis in the cytoplasm of the vitellogeneic oocyte and formation of chorion (secondary egg membrane) of the ovarian eggs. Spawning occurred between April and June. The spawning period was once a year and the peak took place between May and June. This species belongs to semelparity. According to changes in biochemical contents of the ovary and the digestive organ, monthly variations of moisture, total protein, total lipid and glycogen contents (%) in the ovary showed a negative correlationship with those of the trunk tissues including the digestive organ. Accordingly, it is assumed that the ovary only may be received nutrient supply (total lipid content) for gonadal development from the trunk tissues including the digestive organ (r = -0.55, p < 0.05).

• Solar Energy
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• v.11 no.2
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• pp.51-62
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• 1991

Heat transfer characteristics for heat retrieving processes in a paraffin-filled horizontal circular cylinder was studied. Theoretical and experimental analyses were carried out. In the theoretical analysis, solid and liquid phases were treated separately. Namely, convection for liquid and conduction for solid phase were investigated respectively. The retrieved heat was calculated from the experimentally determined solidified mass. Furthermore, the effects of initial temperature of the liquid and cooling temperature on the heat discharge rate were also studied. In the heat retrieving process, the governing factor for the solidifying rate is the cooling temperature, because most of the liquid sensible heat is rapidly discharged in the initial stage of solidification. Hence heat transfer mechanism during heat retrieving process can be safely considered as conduction. In the cut of frozen paraffin, there showed an empty space in the upper region. It is caused by the temperature drop in the liquid paraffin. While volume shrinkage caused by phase transition was indiscernible. Irrespective of cooling temperature and initial liquid temperature, solidified mass was well-correlated with the product of Fourier number and Stefan number in the solid phase.

• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.379-389
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• 2020

In this study, the flow and noise performances of high-speed fan motor unit for cordless vacuum cleaner is improved by optimizing the impeller which drives the suction air through flow passage of the cordless vacuum cleaner. Firstly, the unsteady incompressible Reynolds averaged Navier-Stokes (RANS) equations are solved to investigate the flow through the fan motor unit using the computational fluid dynamics techniques. Based on flow field results, the Ffowcs-Williams and Hawkings (FW-H) integral equation is used to predict flow noise radiated from the impeller. Predicted results are compared to the measured ones, which confirms the validity of the numerical method used. It is found that the strong vortex is formed around the mid-chord region of the main blades where the blade curvature change rapidly. Given that vortex acts as a loss for flow and a noise source for noise, impeller blade is redesigned to suppress the identified vortex. The response surface method using two factors is employed to determine the optimum inlet and outlet sweep angles for maximum flow rate and minimum noise. Further analysis of finally selected design confirms the improved flow and noise performance.

• Molecules and Cells
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• v.19 no.1
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• pp.114-123
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• 2005

Nitropyrene, the predominant nitropolycyclic hydrocarbon found in diesel exhaust, is a mutagenic and tumorigenic environmental pollutant that requires metabolic activation via nitroreduction and ring oxidation. In order to determine the role of ring oxidation in the mutagenicity of 1-nitropyrene, its oxidative metabolites, 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide, were synthesized and their mutation spectra were determined in the coding region of hprt gene of CHO cells by a PCR amplification of reverse-transcribed hprt mRNA, followed by a DNA sequence analysis. A comparison of the two metabolites for mutation frequencies showed that 1-nitropyrene 9,10-oxide was 2-times higher than 1-nitropyrene 4,5-oxide. The mutation spectrum for 1-nitropyrene 4,5-oxide was base substitutions (33/49), one base deletions (11/49) and exon deletions (5/49). In the case of 1-nitropyrene 9,10-oxide, base substitutions (27/50), one base deletions (15/50), and exon deletions (8/50) were observed. Base substitutions were distributed randomly throughout the hprt gene. The majority of the base substitutions in mutant from 1-nitropyrene 4,5-oxide treated cells were $A{\rightarrow}G$ transition (15/33) and $G{\rightarrow}A$ transition (8/33). The predominant base substitution, $A{\rightarrow}G$ transition (11/27) and $G{\rightarrow}A$ transition (8/27), were also observed in mutant from 1-nitropyrene 9,10-oxide treated cells. The mutation at the site of adenine and guanine was consistent with the previous results, where the sites of DNA adduct formed by these compounds were predominant at the sites of purines. A comparison of the mutational patterns between 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide showed that there were no significant differences in the overall mutational spectrum. These results indicate that each oxidative metabolite exhibits an equal contribution to the mutagenicity of 1-nitropyrene, and ring oxidation of 1-nitropyrene is an important metabolic pathway to the formation of significant lethal DNA lesions.

• Molecules and Cells
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• v.38 no.11
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• pp.950-958
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• 2015

BCS1L gene encodes mitochondrial protein and is a member of conserved AAA protein family. This gene is involved in the incorporation of Rieske FeS and Qcr10p into complex III of respiratory chain. In our previous study, AluYRa2-derived alternative transcript in rhesus monkey genome was identified. However, this transcript has not been reported in human genome. In present study, we conducted evolutionary analysis of AluYRa2-exonized transcript with various primate genomic DNAs and cDNAs from humans, rhesus monkeys, and crabeating monkeys. Remarkably, our results show that AluYRa2 element has only been integrated into genomes of Macaca species. This Macaca lineage-specific integration of AluYRa2 element led to exonization event in the first intron region of BCS1L gene by producing a conserved 3' splice site. Intriguingly, in rhesus and crabeating monkeys, more diverse transcript variants by alternative splicing (AS) events, including exon skipping and different 5' splice sites from humans, were identified. Alignment of amino acid sequences revealed that AluYRa2-exonized transcript has short N-terminal peptides. Therefore, AS events play a major role in the generation of various transcripts and proteins during primate evolution. In particular, lineage-specific integration of Alu elements and species-specific Alu-derived exonization events could be important sources of gene diversification in primates.

• Food Science of Animal Resources
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• v.36 no.5
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• pp.665-670
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• 2016

The objectives of this study were conducted to characterize pepsin-soluble collagen (PSC) extracted from bones (PSC-B), skins (PSC-S), and tendons (PSC-T) of duck feet and to determine their thermal and structural properties, for better practical application of each part of duck feet as a novel source for collagen. PSC was extracted from each part of duck feet by using 0.5 M acetic acid containing 5% (w/w) pepsin. Electrophoretic patterns showed that the ratio between α₁ and α₂ chains, which are subunit polypeptides forming collagen triple helix, was approximately 1:1 in all PSCs of duck feet. PSC-B had slightly higher molecular weights for α₁ and α₂ chains than PSC-S and PSC-T. From the results of differential scanning calorimetry (DSC), higher onset (beginning point of melting) and peak temperatures (maximum point of curve) were found at PSC-B compared to PSC-S and PSC-T (p<0.05). Fourier transform infrared spectroscopy (FT-IR) presented that PSC-S and PSC-T had similar intermolecular structures and chemical bonds, whereas PSC-B exhibited slight difference in amide A region. Irregular dense sheet-like films linked by random-coiled filaments were observed similarly. Our findings indicate that PSCs of duck feet might be characterized similarly as a mixture of collagen type I and II and suggest that duck feet could be used for collagen extraction without deboning and/or separation processes.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.366-370
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• 1992

Sediment samples were collected from the stations 0101-0921 located between N $32^{\circ}$30'~$34^{\circ}$30' and E $123^{\circ}$30'-$128^{\circ}$30' during July 31-August lO. 1988. The distributions of total heterotrophic bacteria, freshwater bacteria and hydrocarbon degrading bacteria were studied. Each bacterial distribution was in the range of $3{\times}10^{5}~9.2{\times}10^{6}CFU/cm^{3}$sediment, $3{\times}10^{3}~2.1{\times}10^{6}CFU/cm^{3}$ sediment and $2{\times}10^{4}~6.2{\times}10^{6}CFU/cm^{3}$ sediment. respectively. The percent of hydrocarbon degrading bacteria against total heterotrophic bacteria was 0.7-73,2 % which was much higher than other marine sediments reported. These values were statistically analyzed with the percent of freshwater bacteria against total heterotrophic bacteria. These two parameters were well correlated with the correlation coefficient r= 0.60058 (n=34) and P=0.OOO2. This means that the distributions of hydrocarbon degrading bacteria and freshwater bacteria in the research area were affected together by the fresh water discharge into the sea environment. Therefore it can be concluded that the distribution of hydrocarbon degrading bacteria in the sediment of South Sea was affected by petroleum hydrocarbon input from terrestrial region through rivers.

• Journal of Microbiology and Biotechnology
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• v.28 no.6
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• pp.976-986
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• 2018

Knowledge about the gut bacterial communities associated with insects is essential to understand their roles in the physiology of the host. In the present study, the gut bacterial communities of a laboratory-reared insecticide-susceptible (IS), and a field-collected insecticide-resistant (IR) population of a major rice pest, the brown planthopper Nilaparvata lugens, were evaluated. The deep-sequencing analysis of the V3 hypervariable region of the 16S rRNA gene was performed using Illumina and the sequence data were processed using QIIME. The toxicological bioassays showed that compared with the IS population, IR population exhibited 7.9-, 6.7-, 14.8-, and 18.7-fold resistance to acephate, imidacloprid, thiamethoxam, and buprofezin, respectively. The analysis of the alpha diversity indicated a higher bacterial diversity and richness associated with the IR population. The dominant phylum in the IS population was Proteobacteria (99.86%), whereas the IR population consisted of Firmicutes (46.06%), followed by Bacteroidetes (30.8%) and Proteobacteria (15.49%). Morganella, Weissella, and Enterococcus were among the genera shared between the two populations and might form the core bacteria associated with N. lugens. The taxonomic-to-phenotypic mapping revealed the presence of ammonia oxidizers, nitrogen fixers, sulfur oxidizers and reducers, xylan degraders, and aromatic hydrocarbon degraders in the metagenome of N. lugens. Interestingly, the IR population was found to be enriched with bacteria involved in detoxification functions. The results obtained in this study provide a basis for future studies elucidating the roles of the gut bacteria in the insecticide resistance-associated symbiotic relationship and on the design of novel strategies for the management of N. lugens.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.25-31
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• 1974

This survey was aimed to accumulate basic data of aphid population at the Horticultural Experiment Station at Suweon. The yellow pan traps were setted at five locations (Fig.1.), and ran from May 1 to October 31. 1970. About one hundred and twenty species of aphids were trapped, including 24 species of plant vims vectors. Of these, dominant species were as follows: (Asterisk shows virus vector) Aphid species No. of catches * Aphis spiraecola PATCH 2,635, * Aphis craccivora KOCH 2,377, * Myzus persicae SULXER 2,111, Capitophorus hippophaes javanicus H.R. LAMBERS 2,051, Anoecia fulviabdominalis SASAKI 1,480, * Aphis gossypii GLOVER 867, * Macrosiphum avenae FABRICIUS 859, Cervaphis quercus TAKAHASHI 692, * Lipaphis erysimi KALTENBACH 645, Pleotrichophorus chrysanthemi THEOBALD 489, The above 10 species consisted $76.5\%$ of total catches and the 24 vector species consisted $55.5\%$. The curve of the seasonal occurrence of flying aphids at Horticultural Experiment Station shows bimodal, typical for the temperate region. The total number of trapped aphids at the Station from May to September, 1970, were less than that of average yearly catches at the College of Agriculture from 1967 to 1970. Thi, low numbers at Horticultural Experiment Station may attribute to the frequent spraying of insecticides from Spring to Summer on growing crops there. But the aphids population increase suddenly in the middle of October. This might be resulted from cease of insecticide applications and migration of aphids from summer host to winter host plants.