• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.5
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• pp.393-400
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• 2011

The mass transport is very complicated at the area which has the macro tide and complex geometry such as Gyeonggi bay. Especially, the long period current has a strong influence on the estuarine ecosystem and the long-term distribution of substances. The long period current is caused by several external forcing, whose unique characteristic varies spatially and temporally. The variation characteristics of long period current is analysed and its generation mechanism is studied. The tidal nonlinear constituents such as overtide and compound tide are generated due to nonlinear interaction and it causes mean sea level setup. The tidal wave propagating up into estuary is transformed rapidly by decrease of cross-sectional area and depth. Therefore the mean sea level is getting rise toward upriver. The high and low tide level is similar between down-river(Incheon) and up-river(Ganghwa) during neap tide when the tidal deformation is decreased. The tidal phase difference between two tidal stations causes a periodic fluctuation of sea level difference. The low water level of Ganghwa station during spring tide does not descend under EL(-)2.5 m, but the low water level of Incheon fall down under EL(-)4.0 m. The variation of tidal range and its sea level are increased during spring tide. It is found that the long period current $M_{sf}$ is quite similar to that of sea level difference between the two tidal stations. It means that the sea surface inclination caused by the spatial difference of tidal deformation is important forcing for the generation of long period current.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.642-652
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• 2014

The synthesis of octenyl succinyl ${\beta}$-gucan (OSA-${\beta}$-glucan) was carried out and its interfacial properties at the oil-water interface and in emulsion systems were investigated. An aqueous ethanol system as a reaction media was used to facilitate the synthesis process; 10% (w/w) ethanol found to be the best as it showed a maximum degree of substitution (DS: 0.0132). FT-IR showed a characteristic absorption spectrum at $1736cm^{-1}$, indicating the esterification of octenyl succinyl groups to ${\beta}$-glucan backbone. As for interfacial tension measurements, it was decreased with increasing concentration of OSA-${\beta}$-glucan in the aqueous phase and when NaCl was added to aqueous OSA-${\beta}$-glucan solution in the range of 0.01 M to 0.1 M and also when pH was raised (pH 3 ~ pH 9). In systems of emulsion stabilized with OSA-${\beta}$-glucan, fat globule size found to decrease with increasing concentration of OSA-${\beta}$-glucan, showing a critical value of about $0.32{\mu}m$ at 0.5 wt%. When the OSA-${\beta}$-glucan emulsions were stored, it was found that fat globule size was increased with storage time and particularly pronounced increase was observed in emulsion with 1% OSA-${\beta}$-glucan, possibly due to depletion flocculation. Results of creaming stability evaluated by light scattering technique showed that it was more stable in emulsions containing smaller fat globule size. Surface load of OSA-${\beta}$-glucan in emulsions increased with increasing concentration of OSA-${\beta}$-glucan, suggesting a multilayer adsorption.

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.307-318
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• 1998

Accuracy of rectal palpation and ultrasonography for differential diagnosis of subestrous dairy trows were investigatedl using the result of pIRsma progesterone assay. The ovaries were examined 2 times of 10 days interval in 520 posearom and postinsemination subestroHs dairy cows, using rectal palpation and B-mode transrectal ultrasonography. The results of rectal palpation, ultrasonographic examination and measurement of plasma progesterone profiles in 520 subestrous dairy cows were silent brat or error of estrus detection 303 (58.3%), persistent corpus luteum 59 (11.3%), follicular cyst 37 (7.1%), luteal cyst 16 (3.1%), inactive ovary 9 (1.7%), granulosa tumor 1 (0.2%), hydmsalphinx 1 (0.2%), endomehris 81 (15.6%), pyometra 12 (2.3%) and mummified fetus 1 (0.2%), respectively. Accuncy of rectal palpation and ultrasonography for diagiosing ovarian disordeir based on plasma progesterone profiles were silent heat or error of estrus detection 80.5% and 96.7%$\boxUl$ persistent corpus luteum 57.6% and 94.9%, follicular cyst 62.5% and 91.9%1 luteal cyst 62.5% and 87.5%, maclive ovary 55.6% and 88.9% and granulosa cell tumor 100% and 100%, respectively. Acnuucy of rectal palpation for diagnosing uterine disorders based on ultrasonography was pyometra 75.0%1 endometritis 51.9% and mummified fetus 100%, respectively. Cbaracteristic ultrasonographic appearances of ovaries in subestrous dairy cows were as follows; Silent heat or error of estrus detection: anechoic follicle or hypoechoic corpus luteum than ovarian stroma was alternately present on Day 0 (first examination) and Day 10. Follicular cyst: uniformly nonechogenic ovarian structure $\geq $ 25 mm in diameter with a wall < 3 mm was present in ipsilateral on Day 0 and Day 10. Luteal cyst: luteal cyst was similar to follicular cysts but thickness of cystic wall was $\geq $ 3 mm. Inactive ovary : structures within ovaries was not present on Day 0 Bnd Day 10. Characteristic uthssonograpsc appearances of uterus in subestrous dairy cows were as follows; Endometritis: characterized by uterine lumen containing fluid in which 'snowy'echogenic particles art suspended. Pyometra: ultrasonographic appearance of pyometra was diffuse echogenic particles distributed in fluid within the distended uterus, and a thickened uterine wall. These results indicated that ultrasonography was practical far diagnosing reproductive disorders. To diagnosing ovarian disorders, ultrasonography should be carried out 2 times of 10 days interval and rndometritis should be differentiated with uterus of luteal phase in normal cycling cows.

• Journal of Embryo Transfer
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• v.23 no.1
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• pp.13-18
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• 2008

Vaginal cytology with behavioral observation was performed in 34 estrous cycles in 16 Miniature Schnauzer dogs to evaluate the its usefulness. The mean duration of proestrus and estrus in Miniature Schnauzer based on behavioral observation and vaginal cytology was $7.58{\pm}1.50$ (Mean ${\pm}$S.D., range: $5{\sim}10$) and $8.46{\pm}2.82\;(6{\sim}17)$ days for proestrus, and $6.97{\pm}1.66\;(4{\sim}10)$ and $10.29{\pm}2.61\;(6{\sim}19)$ days for estrus, respectively. The duration of each phase of the estrous cycle was not significantly different based on between behavioral observation and vaginal cytology. The gestational length from the first day of male acceptance was $66.55{\pm}2.91\;(64{\sim}76)$ days, $57.70{\pm}1.92\;(54{\sim}62)$ days from the first male refusal, and $56.90{\pm}1.62\;(54{\sim}60)$ days from the onset of cytologic diestrus, respectively. Vaginal cytology during the estrous cycle were significantly characteristic of large intermediate cells in proestrus, anuclear cells in estrus, small intermediate cells in diestrus, and parabasal cells and small intermediate cells in anestrus (p<0.001), respectively. Cornification index (CI) by vaginal cytology was higher in proestrus ($69.90{\pm}1.44%$) and estrus ($91.35{\pm}1.09%$), then it was decreased in diestrus ($13.53{\pm}1.28%$) and anestrus ($1.16{\pm}1.26%$).

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.4
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• pp.55-66
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• 1993

Upon freezing a soil swells due to phase change and its compression stress increase a lot. As the soil undergo thawing, however, it becomes a soft soil layer because the 'soil changes from a solid state to a plastic state. These changes are largely dependent on freezing temperature and repeated freezing-thawing cycle as well as the density of the soil and applied loading condition. This study was initiated to describe the effect of the freezing temperature and repeated freezing-thawing cycle on the unconfined compressive strength. Soil samples were collected at about 20 sites where soil structures were installed in Kangwon provincial area and necessary laboratory tests were conducted. The results could be used to help manage effectively the field structures and can be used as a basic data for designing and constructing new projects in the future. The results were as follows ; 1. Unconfined compressive strength decreased as the number of freezing and thawing cycle went up. But the strength increased as compression speed, water content and temperature decreased. The largest effect on the strength was observed at the first freezing and thawing cycle. 2. Compression strain went up with the increase of deformation speed, and was largely influenced by the number of the freezing-thawing cycle. 3. Secant modulus was responded sensitivefy to the material of the loading plates, increased with decrease of temperature down to - -10$^{\circ}$C, but was nearly constant below the temperature. Thixotropic ratio characteristic became large as compression strain got smaller and was significantly larger in the controlled soil than in the soil treated with freezing and thawing processes 4. Vertical compression strength of ice crystal(development direction) was 3 to 4 times larger than that of perpendicular to the crystal. The vertical compression strength was agreed well with Clausius-Clapeyrons equation when temperature were between 0 to 5C$^{\circ}$, but the strength below - 5$^{\circ}$C were different from the equation and showed a strong dependency on temperature and deformation speed. When the skew was less then 20 degrees, the vertical compression strength was gradually decreased but when the skew was higher than that, the strength became nearly constant. Almost all samples showed ductile failure. As considered above, strength reduction of the soil due to cyclic freezing-thawing prosses must be considered when trenching and cutting the soil to construct soil structures if the soil is likely subject to the processes. Especially, if a soil no freezing-thawing history, cares for the strength reduction must be given before any design or construction works begin. It is suggested that special design and construction techniques for the strength reduction be developed.

• Journal of Mushroom
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• v.10 no.4
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• pp.224-235
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• 2012

Quality change of winter mushroom were investigated during storage and distribution phase as influenced by storage temperature. According to storage period and temperature, amino acids, were analysed and quantified with the mushroom fruiting bodies using HPLC and morphological characteristics were investigated. Characteristic changes of winter mushroom fruiting bodies were described as follows during storage according to the storage temperature. Looking at the results of the analyzed amino acid contents, temperature between $-1^{\circ}C$ and $4^{\circ}C$ was optimal condition for the storage. At $4^{\circ}C$, the chemical composition tended to be maintained. On the other hand, the results indicate the rapid loss of nutrition at $-1^{\circ}C$ within 7 days of storage. Exceptionally, proline was shown to be increased. Brown line mushroom had a larger loss than white line mushroom. Based on this result, brown line mushroom have shown significant differences among varieties. Therefore, winter mushroom should be stored at $4^{\circ}C$ to minimize nutrient loss and to maintain freshness and mushrooms should be consumed within 14 days after harvest.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.85-92
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• 2008

Pseudomonas aeruginosa is an opportunistic human pathogen, causing a wide variety of infections including cystic fibrosis, microbial keratitis, and burn wound infections. The cell-to-cell signaling mechanism known as quorum sensing (QS) plays a key role in these infections and the QS systems of P. aeruginosa have been most intensively studied. While many literatures that introduce the QS systems of P. aeruginosa have mostly focused on two major acyl-homo serine lactone (acyl-HSL) QS signals, N-3-oxododecanoyl homoserine lactone (3OC12) and N-butanoyl homoserine lactone (C4), several new signal molecules have been discovered and suggested for their significant roles in signaling and virulence of P. aeruginosa. One of them is PQS (Pseudomonas quinolone signal; 2-heptyl-3-hydroxy-4-quinolone), which is now considered as a well-characterized major signal meolecule of P. aeruginosa. In addition, recent researches have also suggested some more putative signal molecules of P. aeruginosa, which are diketopiperazines (DKPs) and pyocyanin. DKPs are cyclic dipeptides and structurally diverse depending on what amino acids are involved in composition. Some DKPs from the culture supernatant of P. aeruginosa are suggested as new diffusible signal molecules, based on their ability to activate Vibrio fischeri LuxR biosensors that are previously considered specific for acyl-HSLs. Pyocyanin (1-hydroxy-5-methyl-phenazine), one of phenazine derivatives produced by P. aeruginosa is a characteristic blue-green pigment and redox-active compound. This has been recently suggested as a terminal signaling factor to upregulate some QS-controlled genes during stationary phase under the mediation of a transcription factor, SoxR. Here, details about these newly emerging signaling molecules of P. aeruginosa are discussed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.2
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• pp.3438-3453
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• 1974

Unmeasured value of water for human lives is widely approved, but the water as one of natural resources cannot be evaluated with ease since it changes itself ceaselessly by flowing-out or transforming the phase. Major objectives of the study concerned consequently with investigating its potentiality and evaluating its time seriesly availabity in a volumatic unit. And the study was performed to give the accurate original data to the planners concerned. Some developed rational methods of predicting runoff related to hydrological factors as precipitation, were to be discusseed for their theorical background and to be introduced whether they needed some corrections or not, comparing their estimation with actual runoff from synthetic unit-hydrograph methods. To do so, the study was performed to select Kongju Station, located at the watershed of the Keum River, and to collect such hydrological data from 1962 to 1972 as runoff, water level, precipitation, and so on. On the other hand, the hydrological characteristics of runoff were concluded more reasonably in numerical values, with calculating the the ratio of daily runoff to annual discharge of the flow in percentage, as. the distribution ratio of runoff. The results of the study can be summarized as follows; (1) There needed some consideration to apply the Kajiyama's Formula for predicting monthly runoff of rivers in Korea.(2) The rational methods of predicting runoff might be recommended to become less theorical and reliable than the unique analyzation of data concerned in each given water basin. The results from the Keum River prepared above would be available to any programms concerned. (3) The most accurate estimation for runoff could be suggested to synthetic unithydrograph methods calculated from the relation between each storm and runoff. However it was not contained in the study. (4) The relations between rainfall and runoff at KongJu Station were as following table. The table showed some intersting implications about the characteristics of runoff at site, which indicated that the runoff during three months from July to September approached total of 60% of quantity while precipitation concentrated on the other three from June to August. And there were some months which had more amount of runoff than expected values calculated from the precipitation, such as Febrary, March, August, September, Octover, and December, shown in the table. Such implications should be suggested to meet any correction factors in the future formulation concerned with the subjects, if any rational methods would be required.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.4
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• pp.207-218
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• 2013

This study is based on a series of numerical modeling experiments to understand the circulation and its change in the Chunsu Bay (CSB), Yellow Sea of Korea. A skill analysis was performed for the tidal height and tidal current of the observation data using the amplitude and phase of the 4 major tidal constituents respectively for verification of modeling experimental results. As a result, most of the skill score was seen to be over 90%, so numerical model experiment results can be said to be in good agreement with the observed tidal height and tidal current. Tidal wave proceeded from the entrance of the CSB towards inside, and the tidal range gradually increased to the north. It took about 10 to 30 minutes for the tidal wave to reach to northern end. The tidal wave showed a characteristic to rotate counter-clockwise in the southern part. The tidal current flowed to the north-south direction along the bottom topography; the angle of the major axis appeared alongside the isobath. It showed the characteristics of reversing tidal current with the minor axis less than 10% of the major axis. The strength of the tidal residual current that is influenced by geographical factors including bathymetry and coastline showed the range of 1~30 cm/sec, greater in the south channel and smaller in northern Bay. Two pairs of cyclonic/anti-cyclonic eddies around Jukdo and 3~4 pairs of strong eddies at the southern part of CSB in hundreds of m to a few km size by relative vorticity derived from the tidal residual current.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.76-92
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• 1997

Porpilyromonas endodontalis is specifically involved in endodontic infections. The bacterium can be isolated almost exclusively only from infected rool canals. P. gingivalis also has been implicated in endodontic infection. Pathogemcity of P. gingival is is attributed to a variety of virulence factors, especially proteases, produced by the bacterium. Importance of P. endodontalis in endodontic infection has been revealed. However, the pathogenic property of P. endodontalis has not been extensively studied. The present study was undertaken to characterize the proteolytic activity of P. endodontalis and compare the activity with that of P. gingivalis which has the most potent and diverse proteases among oral bacteria. For this purpose, culture supematants(SUP) and cell extracts(CE) were obtained from these two bacteria and were subjected to zymography using 15% polyacrylamide gel copolymerized with gelatin, type I, IV collagens or albumin. Hydrolysis of the collagens was further investigated by the cleavage assay using native type I and IV collagens in solution-phase. The results were as follows: 1. P. endodontalis apparently has a proteolytic activity that is comparable with that of P. gingivalis. 2. SUP and CE obtained from P. endodontalis and P. gingival is showed the strongest activity for gelatin, followed by type I and IV collagens, and albumin. 3. In the zymography, no noticeable difference in proteolytic activity for gelatin and albumin between the SUP and CE was observed, but in the cleavage assay using native collagens, the SUP showed a stronger collagenolytic activity than the CE. 4. The gelatinolytic activity of both the SUP and CE from these two bacteria was diminished in the presence of $CaCl_2$ or reducing agents such as ${\beta}$-mercaptoethanol and dithiothreitol(DTT). 5. Type I(calf skin and human placenta) collagenolytic activity of P. endodontalis and P. gingivalis was reduced by DTT but not affected by $CaCl_2$. The inhibitory effect of DTT, however, was reduced to some extent by $CaCl_2$. 6. Type IV collagenolytic activity of these two bacteria was not affected by $CaCl_2$ but increased to some extent in association with the reducing agents. 7. Hydrolysis of albumin by P. endodontalis and P. gingivalis was demonstrated only in the presence of the reducing agents. The overall results indicate that with respect to proteolytic activity, P. endodontalis appears to be as potent as P. gingivalis, or maybe more, and its proteolytic characteristic is similar to that of P. gingivalis. This suggests that P. endodontalis has so potent proteolytic activity that can participate by itself in endodontic infections and apical periodontitis, causing tissue destruction.