• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.1
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• pp.24-29
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• 2003

In the previous reports, the authors isolated two strains of marine bacteria, Shewanella sp. SR-14, which has Chaetonros sp. growth inhibition activity, and Vibrio alginolyticus, that did not affect growth of the alga. In the present study, fatty acid compositions of diatoms, Chaetoceros calcitrans and Skeletonema costatum, and marine bacteria, Shewanella sp. SR-14 and V. alginolyticus, were analyzed. Changes of fatty acid composition in the diatoms grown with the marine bacteria were also determined. Major fatty acids of Sbewanella sp. SR-14 were 16:1n-7 $(29.4\%)$ and 16:0 $(19.2\%)$ during incubation in peptone broth at $20^{\circ}C$ for 3 days. The compositions of V. alginolyticus detected were 16:0 $(23.7\%),$ 16:1n-7 $(27.7\%)$ and 18:1n-7 $(21.0\%).$ C. calcitrans consisted of 16:1n-7 $(33.3\%),$ 16:0 $(27.1\%)$ and 14:0 $(12.1\%).$ S. costatum mainly contained 16:1n-7 $(28.9\%),$ 16:0 $(21.6\%)$ and 20:5 $(19.8\%).$ When halves of cell numbers of C. calcitrans were moribund cells by Shewanella sp. SR-14, the C. calcitrans and S. costatum simultaneously cultured with the bacteria were harvested by filtration with GE/D glass microfibre filter. In the fatty acid composition of both diatoms, saturated fatty acid contents in both diatoms grown with Shewanella sp. SR-14 were decreased, but unsaturated fatty acid contents were increased. The differences were greater in C. calcitrans than those in S. costatum. During the growth of diatoms with V. alginolyticus, C. calcitrans showed increase of saturated fatty acid contents and decrease of unsaturated fatty acid contents; however, S. costatum did not show sharp difference in fatty acid content. In this study, Shewanella sp. SR-14, which showed growth inhibition activity against C. calcitrans, influenced on the changes of fatty acid contents in the diatom. It was suggested that increased unsaturated fatty acid was synergistically activated algal growth inhibition activity of Shewanella sp. SR-14.

• Journal of Microbiology and Biotechnology
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• v.7 no.3
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• pp.174-179
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• 1997

In order to investigate effect of glucooligosaccharide (GOS) prepared by extrusion process as a bifidogenic factor, cultivation of Bifidobacterium sp., Bacteroides fragilis and Clostridium perfringens was done and analyzed. B. fragilis and C. perfringens were able to utilize only 16% and 11% of the oligosaccharides in GOS, respectively, whilst Bifidobacterium sp. FBD-22 could utilize 38%. Especially, many kinds of oligo saccharides in GOS were able to be utilized selectively only by Bifidobacterium sp.. In case that GOS, as a carbon source, was used in the co-cultivation by Bifidobacterium sp., B. fragilis and C. perfringens, growth of Bifidobacterium sp. was not influenced by the existence of B. fragilis and C. perfringens. Bifidobacterium sp. showed advantage on carbon source competition for GOS with B. fragilis. Acetic acid, antimicrobial agent in the intestine, was produced two times more from GOS than glucose in co-cultures of three strains. Therefore, it is suggested that GOS can be a potent bifidogenic factor which proliferates the population of Bifidobacterium sp. and may finally improve the intestinal environments of human.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1563-1576
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• 2017

This paper presents a novel switching pattern current control (SP-CC) scheme, which is applied in three-phase voltage-source converters (VSCs). This scheme can select the optimal output switching pattern (SP) by referring the basic principle of space vector modulation (SVM). Moreover, SP-CC is a method without a carrier wave. Thus, the implementation process is concise and easy. When compared with the conventional hysteresis current control (C-HCC) and the space vector-based hysteresis current control (SV-HCC), the SP-CC has the performances of faster dynamic response of C-HCC and less switching number (SN) of SV-HCC. In addition, it has less harmonic contents in the three-phase current, along with a lower switching loss and a higher efficiency. Moreover, the hysteresis bandwidth and Clarke conversion are not required in the SP-CC. The effectiveness of the presented SP-CC is verified by simulation and experimental test results. In addition, the advantages of the SP-CC, when compared with the C-HCC and SV-HCC, are verified as well.

• Korea Journal of Hospital Management
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• v.14 no.4
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• pp.124-148
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• 2009

Objectives : The purpose of this study was to investigate influencing factors on physician's intention to use cyber salesperson(cSP) to promote ethical drugs of pharmaceutical company. We considered influencing factors based on technology acceptance model(TAM) such as usefulness, easy of use, and attitude about cSP, and included trust and joyfulness of cSP. Methods : Measure items were developed from the previous studies. Data were collected from 1,012 physicians by using web-based self-administered structured questionnaire. Results : The major findings were as follows; First, attitude and intention to use cSP were not significantly varied by socio-demographic variables, such as sex, age, location, and Internet surfing time per day. Also, physician's characteristics such as training and professional level and type of employment were not significant to the variation of attitude and intention to use cSP. Second, structural equation modeling(SEM) analysis shows that usefulness and joyfulness were influencing factors of intention to use. Attitude was revealed as significant mediating factor to intention to use. Usefulness has indirect effect on intention to use via attitude. However, trust has not significant effect on intention to use, due to suppression effect. Conclusions : This results implies that cSP will be a useful agent to promote the ethical drugs to physician. Usefulness and joyfulness should be considered as important factors in designing and operating cSP in the Internet.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.350-354
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• 2009

A Gram-negative, alginate lyase-producing bacterium was isolated from the Haeundae Coast, Korea. The isolated strain N7151-6 produced alginate lyase. The optimal temperature and pH for growth were found to be $30^{\circ}C$ and pH 8.0, respectively. This strain can be grown at the NaCl concentration of 0-7% (w/v). Analysis of 16S rDNA sequence and physiological profiling indicated that the strain N7151-6 belonged to Pseudomonas sp. The enzyme alginate lyase produced by Pseudomonas sp. N7151-6 was partially purified by ultrafiltration (MWCO= 30 kDa). The optimum pH and temperature for the activity of the purified enzyme were found to be 7.0 and $30^{\circ}C$, respectively. The enzyme was stable at the pH range of 5.0-9.0 and temperature range of $23-30^{\circ}C$. The total activity of alginate lyase produced was reached about 110 unit/L.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.319-328
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• 1997

To develop a beneficial microbial feed for the cultivation of rotifer, Brachionus plicatilis, an aerobic photosynthetic bacterium, Erythrobacter sp. $S\;\pi-I$ was isolated from marine structure at Haeundae beach in Pusan, Korea. Feeding effects of Erythrobacter sp. $S\;\pi-I$ on the growth of rotifer were analyzed comparing to other feeds such as PSB (purple nonsulfur bacteria), Chlorella sp. and baker's yeast. Erythrobacter sp. $S\;\pi-I$ contained more linoleic acid $(C_{18:3\omega3})$ and oleic acid $(C_{18:1\omega9})$ and amino acids than PSB (purple nonsulfur bacteria), Chlorella sp. and baker's yeast. The rotifer fed on Erythrobacter sp. $S\;\pi-I$ showed better effects than those fed on other feeds in the individual growth, size and weight. Also, the rotifer especially contained more eicosapentaenoic acid $(C_{20:5\omega3})$ and docosahexaenoic acid $(C_{22:6\omega3})$ in case of Erythrobacter sp. $S\;\pi-I$ feeding than the other feeds. In case of the feed of PSB and baker's yeast docosahexaenoic acid $(C_{22:6\omega3})$ did not show. In amino acid analysis, the rotifer fed on Erthrobacter sp, $S\;\pi-I$ showed more amino acid content comparing to those fed on other diets. Especially, arginine, isoleucine, histidine, lysine, methionine, phenylalanine, threonine, which are essential amino acid for fish growth, showed high contents. These results suggested that the aerobic photosynthetic bacterium, Erythrobacter sp. $S\;\pi-I$ would be a beneficial microbial teed for the cultivation of rotifer.

• Analytical Science and Technology
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• v.13 no.2
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• pp.200-207
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• 2000

The growth mechanisms of graphite spherulite both in the nodular cast iron and the high pressuretreated Ni-C alloy were investigated by SEM, HRTEM and EELS. The internal microstructure and lattice image of graphite spherulite extracted from Ni-C alloy were compared with those of graphite spherulite extracted from the nodular cast iron. The ratios of $sp^2$ and $sp^3$ bonding in the respective graphite spherulite measured by EELS, are compared each other. The graphite spherulite of Ni-C alloy had little internal defects and much $sp^3$ carbon species compared to that of the nodular cast iron. Present difference in microstructural features and bonding characters indicated that the graphite spheruites in the high pressuretreated Ni-C alloy grew by different mechanism compared with those in the nodular cast iron.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.1010-1016
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• 2016

The quality characteristics of seasoned pork with sauces containing different concentrations of fermented Oenothera biennis juice such as 5% (5-SP), 10% (10-SP) and 15% (15-SP) during storage for 15 days at $10^{\circ}C$ were investigated. The pH level decreased after storage for 6 days and pH 4.83~4.90 after storage for 15 days in all tested seasoned pork. The titratable acidity increased significantly after 6 days but did not show significant differences between seasoned pork. The total bacteria of seasoned pork were $10^7CFU/g$ (control) and $10^6CFU/g$ (5-SP and 10-SP) after storage for 9 days. The total bacteria showed a lower 1~2 log cycle in seasoned pork with fermented Oenothera biennis juice compared to control. The volatile basic nitrogen contents of seasoned pork were 18.02 mg% (control), 15.41 mg% (5-SP), 14.47 mg% (10-SP), and 17.51 mg% (15-SP) after storage for 15 days at $10^{\circ}C$, respectively. The a value (red) of pork seasoned with fermented Oenothera biennis juice was higher than that of control and decreased during storage. Cooking loss and water holding capacity of 5-SP and 10-SP were better than those of control and 15-SP during storage. The 5-SP showed the best sensory score in taste (4.00), color (4.00), flavor (3.91), and overall acceptability (4.09) among various seasoned pork groups.

• Journal of Life Science
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• v.19 no.3
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• pp.366-372
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• 2009

In the course of screening of useful enzyme-producing microorganisms from marine sedimentary layers, we isolated 2 amylase producing strains and tested their amylase producing activities. Analyses of 16S rDNA sequences and biochemical methods (BIOLOG) of two isolates showed that they were confirmed to be a gram positive Bacillus sp. and gram negative Pseudoalteromonas sp., respectively. Excellent amylase producing strains were termed Bacillus sp. ST-63 and Pseudoalteromonas sp. ST-140, and further studies were conducted on their amylase producing characteristics. Optimum conditions for cell growth in amylase activity were obtained when the isolate (Bacillus sp. ST-63 and Pseudoalteromonas sp. ST-140) was cultured at $30^{\circ}C$ and pH $7{\sim}8$.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.180-189
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• 2001

This study was conducted to investigate the macrobenthic community in Ulsan Bay and Onsan Bay, in November of 1997. The density of benthic animals was 535 md./m2, and the number of species was 117. Polychaeta was the most dominant faunal group, comprising a total of 63 species, and its density was 380 md./m2 The most dominant benthic macrofauna was Cirratulrus cirratulas (2.7%), and followed by Tharyx sp. (16.6%), Ruditapes philippinarum (16.1%), Lumbrineris longifolia (10.3%) and so on. The dominant species occupied their distinct unique distribution area. Tharyx sp., R. philippinarum and Grandidierella sp.1 occurred mainly in Ulsan Bay, L. longifolia and Euchone sp. in Onsan Bay, and C. cirratulas and Cirriforimia tentaculata in both bays. By cluster analysis, study area was divided into 4 station groups: Northern Ulsan Bay (Al), the middle area of Ulsan Bay (Bl), offsea area between Ulsan Bay and Onsan Bay (Bll), and Onsan Bay (C). Northern Ulsan Bay was characterized by low species number and high density. The dominant species were C. cirratulas R. philippinarum and Tharyx sp. The middle area of Ulsan Bay was by low species number and density, and its characteristic species was Grandidierella sp.1. The offsea area between Ulsan and Onsan Bay was by high species number and low density. Onsan Bay was by high species number and high density, and its important species were L. longifolia and Euchone sp.