• Parasites, Hosts and Diseases
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• v.28 no.2
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• pp.71-78
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• 1990

To assess the role of cAMP on the growth and proliferation of Toxoplasma in HL-60 cells we tested the effect of exogenous cAMP and cAMP analogues to the co-culture system of Toxoplasma and HL-60 cells. cAMP, dbcAMP, and br-cAMP stimulated the growth of Texoplasma at a specific concentration, i.e., 100 mM, l00 mM, and 10-1 mM, respectively. There were differences in growth induction kinetics and in the rate of promotion. These results were further verified by treating the co-culture with adenylate cyclase activator, pNHppG, cAMP phosphodiesterase activators, imidasole and A23187, and cAMP phosphodiesterase inhibitors, IBMX, compound 48/80, and theophylline, separately. When the cytosolic cAMP levels increased by the reagents mentioned above, Toxoplasma in the cytoplasm of HL-60 cells stimulated to proliferate more rapidly with concentration-dependent modes compared to the control, and vice versa. It is suggested that some mechanisms are activated by the high levels of cAMP in the cytoplasm, which result in the stimulation of Toxoplasma proliferation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.257-264
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• 1986

The Chromosomes of five cobitid fishes, Cobitis taenia taenia, C. taenia lutheri, C. taenia striata, C. longicorpus and C. koreensis were studied. The karyotypic studies were based on the observations from the flame-drying preparations. The results obtained such as the number of somatic chromosomes, the type of chromosomes according to the centromeric loci and the number of chromosomal arm(AN) were as follows: C. longicorpus, 2n=50, 12m-8sm-30a, AN=70; C. koreensis, 2n=50, 10m-12sm-28a, AN=72; C. taenia taenia, 2n=48, 14m-4sm-30a, AN=66: C. taenia lutheri, 2n=50, 10m-6sm-34a, AN=66; and C. taenia striata, 2n=50, 10m-6sm-34a, AN=66. Peculiarly, in the case of C. taenia lutheri the chromosome number of somatic diploid was found to be 48-51, however, the number of chromosomal arm was 66, irrespective of the difference in the numbers of each somatic genome. It was confirmed there exists the Robertsonian event, one of the chromosomal polymorphism in C.t. lutheri. It was remarked taxonomically that the karyotype of C. taenia taenia of Korea having 48 diploid chromosomes was not identical with that of Europe and Japan with 50 chromosomes. Based on the karyotype analysis the Korean cobitid fishes can be classified roughly into three species groups according to arm numbers and diploid numbers; 1) C. taenia taenia, C. taenia lutheri, C. taenia striata 2) C. koreensis, C. longicor pus, C. rotundicaudata and 3) C. granoei.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.308-319
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• 2020

In this study, the field applicability of the recently constructed multifunctional fishway in Seomunbo, Yeongcheon-si, and Gyeongsangbuk-do were examined. The analysis variables were R/C slab (S1) and R/C+S/C slab (S2), the underground passage standard areas (width × length) were 1.4 m × 0.2 m, 1.4 m × 0.3 m, and 1.4 m × 0.6 m, and the flow velocities were 0.8, 1.2, and 1.6 m/s. As a result of the analysis, the safety of the design of Seomunbo was evaluated. The analysis showed compared to the Seomoon Weir fishway, the maximum stress of S2 decreased by 24 - 32%, the bending moment of the underground passage decreased by 16 - 33%, the maximum stress of the sidewall decreased by 20 - 36%. In addition, the bending moment of the upper slab decreased by 17 - 33%, the maximum stress of the upper slab decreased by 9 - 28%, and the bending moment decreased by 19 - 33%. Complementation was required in the following percentages: 18% and 14% for the maximum stress and bending moment of the underground passage, respectively, 15% and 17% for the maximum sidewall stress and bending moment, respectively, and 11% and 16% for the upper slab maximum stress and bending moment, respectively. The results showed that S2 was superior to that of the Seomoon Weir fishway, and the underground passage size of 1.4 m × 0.3 m was superior to those of 1.4 m × 0.2 m and 1.4 m × 0.6 m, and R/C+S/C slab was superior to that of R/C slab. The findings are expected to be useful for constructing and designing the multifunctional fishway.

• Korean Journal of Microbiology
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• v.25 no.2
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• pp.94-102
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• 1987

Rat liver LDH A-cDNA has been isolated from a .lambda.gt11-rat lover cDNA library and partially characterized. The size of the isolated rat liver LDH A-cDNA if shown to be 1.6Kb and restriction enzyme sites for the rat liver LDH A-cDNA are also mapped. 682-nucleotide sequence coding for 3'-end of rat liver LDH A-cDNA has been analyzed and compared to the nucleotide sequence of the same region of rat $C_6$-glioma cell LDH A-cDNA which has been cloned from the hormonally stimulated cell cultures. The result shows that 177 nucleotide sequences coding for the C-terminal 59-amino acids are identical but 505 nucleotide sequences of 3'-nontranslated region of the two LSH A-cDNA exhibit characteristic differences in thier nucleotide sequences. Computer analysis for the folding structures for 3'-end 400 nucleotide sequences of the two LDH A-cDNA shows a possibility implying that the two LDH A-mRNAs isolated from different tissues of rats may have different half life and therefore their translational efficiency may be different. It has been previously demonstrated that isoproterenol stimulated rat $C_6$ -glioma cell cultures produce LDH A-mRNA showing 2 to 3-fold longer half life in comparison to that of noninduced LHD A-mRNA. The result therefore support for the idea that hormonally stimulated rat $C_6$-glioma cells may produce LDH A-mRNA containing different nucleotide sequences at the 3'-end nontranslated region by which the hormonally induced LDH A-mRNA could have more stable secondary mRAN structure in comparison to that of noninduced LDH A-mRNA.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.4
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• pp.372-380
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• 1996

The operation of Far East Chain(GRI 5970) of Loran - C system had been stopped on June, 1995, but that of Korean Chain(GRI 9930) of Loran - C system which was jointed with North West Pacific Chain(GRI 8930) and Russia Chain(GRI 7950) by international cooperation, was started on January 1996. In this paper, in order to study the accuracy of Loran - C fix of Korean Chain, the authors examined and analyzed the data of the reciever of Loran - C(LC -90, Furuno) and GPS(AccNav Sport super (TM), Eagle) measured automatically and continually for 2 seconds at interval of 5 minutes from November 22, 1992, to January 20, 1996 at the fixed position of National Fisheries University of Pusan, The results obtained were as follows ; 1)The mean time differences of M-W, M-X, and M-Y pair measured in the base observed position were 12333.09${\mu}$s, 28338.44${\mu}$s, and 42806.01${\mu}$s respectively and the mean standard deviations of that were 0.0121${\mu}$s, 0.0290${\mu}$s, and 0.0327${\mu}$s respectively. The daily and monthly variance forms of time difference at each pair appeared in a similar reappearance. 2)The mean standard deviations of the latitude and longitude by Loran - C were 9.1m and 17.4m in W.X pair, 11.5m and 13.7m in W.Y pair, and 8.1m and 29.3m in X.Y pair respectively, and then the probable radiuses within 95% of each pair were 39.2m, 35.7m, and 60.8m, respectively. Therefore, It is to be desired that W.Y par is selected to improve the accuracy in Pusan area. 3)The mean standard deviations of the latitude and longitude by GPS were 15.4m and 15.0m and the probable radius within 95% was 43.4m. 4)The position errors for GPS and each pair of Loran - C were 16.0m to the South in GPS and 265.2m to the East in W.X pair of Loran - C, 279.5m to the North in W.Y pair of that, and 224.3m to the North-West in X.Y pair of that, so GPS is about 250m higher than Loran - C in accuracy.

• Korean Journal of Microbiology
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• v.29 no.6
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• pp.408-415
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• 1991

TOL plsmid size of Flavobacterium odoratum SUB53 was estimated as 83 Md and the optimum concentration of m-toluate degradation by TOL plasmid was 5 mM. $H_{2}$ production by Rhodopseudomonas sphaeroides KCTC1425 was largely dependent on nitrogenase activity and showed the highest at 30 mM malate with 7 mM glutamate as nitrogen source. Nitrogenase activities were inhibited by 0.3 mM $NH_{4}^{+}$ions, to be appeared the decrease of $H_{2}$ production. Conjugation of TOL plasmids from F. odoratum SUB53 and Pseudomonas putida mt-2 to R. sphaeroides showed the optimum at the exponential stage of recipient cells in presence of helper plasmid pRK2013. According to the investigation of catechol-1,2-oxygenase (C-1, 2-O) and catechol-2,3-oxygenase (C-2,3-O) activities of R. sphaeroides C1 (TOL SUB53) and C2 (TOL mt-2), the gene for C-2,3-O is located on TOL plasmid and gene for C-1, 2-O on the chromosome of R. sphaeroides. m-Toluate was biodegraded by TOL plasmid in R. sphaeroides C1 and C2, presumably to be produced $H_{2}$ gas from the secondary metabolites of m-toluate.e.

• Journal of Life Science
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• v.13 no.5
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• pp.751-755
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• 2003

Cyclic AMP receptor proteins(CRP) activate many genes in Escherichia coli by binding of cAMP with not fully known mechanism. CRP existed as apo-CRP in the absence of cAMP, $CRP;(cAMP)_2$$_2$ at low(micromolar) cAMP concentration, or $CRP;(cAMP)_4$ at high(millimolar) concentration of cAMP. This study is designed to measure the thermal stability of S83G CRP, which substituted glycine for serine at amino acid 83 position, with CD spectrapolarimeter at 222nm by the constant elevation of temperature from $20^{\circ]C\; to\; 90^{\circ}C\; at\; 1^{\circ}C/min$. The non-linear regression analysis showed that melting temperatures were 68.4, 72.0, and $82.3^{\circ}C$ for no cAMP, 0.1mM cAMP, and 5mM cAMP, respectively. Result showed the strong thermal stability of CRP by binding of additional cAMP molecules to region between the hinge region and helix-turn-helix(HTH) motif at 5mM cAMP concentration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.18-19
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• 2008

Polycrystalline(poly) 3C-SiC film is a promising structural material for M/NEMS used in harsh environments, bio and fields. In order to realize poly 3C-SiC based M/NEMS devices, the electrical properties of poly 3C-SiC film have to be optimized. The n-type poly 3C-SiC thin film is deposited by APCVD using HMDS$(Si_2(CH_3)_6)$ as single precursor and are in-situ doped using N2. Resistivity values as low as 0.014 $\Omega$cm were achieved. The carrier concentration increased with doping from $3.0819\times10^{17}$ to $2.2994\times10^{19}cm^{-3}$ and electronicmobility increased from 2.433 to 29.299 $cm^2/V{\cdot}s$.

• Horticultural Science & Technology
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• v.18 no.3
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• pp.321-326
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• 2000

To compare germinability of primed seeds with that of water imbibed and nonprimed seeds at different temperatures, percent germination, number of days to attain 50% of the final germination percentage (T50) and mean number of days to germination (MDG) were evaluated at various temperatures ranged from $10^{\circ}C$ to $35^{\circ}C$. Primed carrot seeds in -0.50 MPa PEG 8000 showed higher percent germination at $10^{\circ}C$ or $35^{\circ}C$. Reductions in T50 and MDG values were observed at all germination temperatures when primed with the PEG. The PEG combined with 100 mM $K_3PO_4$ was not as effective as the PEG alone in improving the germinability of carrot seeds. Nonprimed lettuce seeds germinated only 2% at $30^{\circ}C$ or $35^{\circ}C$. However, priming with 50 mM $K_3PO_4$ increased germination to 40% at $30^{\circ}C$ and to 21% at $35^{\circ}C$. In contrast to the single treatment of 50mM $K_3PO_4$, priming lettuce seeds in a mixture of 50mM $K_3PO_4$ and 200 mM $KH_2PO_4$ resulted in a lower percentage of germination, but a significant greater reduction of T50 and MDG. Percent germination was increased when 200 mM $KH_2PO_4$-primed onion seeds and 100 mM $Ca(NO_3)_2$-primed Welsh onion seeds were germinated at $10^{\circ}C$ or $35^{\circ}C$. Combined treatments with $Ca(NO_3)_2$ for onion and with $KH_2PO_4$ for Welsh onion seeds did not improve percent germination, but they significantly reduced T50 and MDG.

• Journal of the Korean Ceramic Society
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• v.36 no.11
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• pp.1261-1265
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• 1999

Effect of SiC particle size of the densification of Al2O3-SiC composite during pressureless sintering was investigated. Two types of SiC powders having average particle size of 0.15${\mu}{\textrm}{m}$ and 3${\mu}{\textrm}{m}$ were used. Densification rate of the specimen containing 0.15${\mu}{\textrm}{m}$ SiC particles was slower than that of the specimen containg 3${\mu}{\textrm}{m}$ SiC particles. Although the relative density of the specimen containing 0.15${\mu}{\textrm}{m}$ SiC particles was below 90% of theoretical density after sintering at 155$0^{\circ}C$ the complete closure of open pores occurred. Therefore full densification could be obtained by subsequent HIP. On the other hand in the specimen containing 3${\mu}{\textrm}{m}$ SiC particles the complete closed pore was observed at 95% of theoretical density. Such a fast pore closure in the specimen containing 0.15${\mu}{\textrm}{m}$ SiC particles is likely to occur as a result of dense reaction layer formation on the specimen surface which is attributed to the high reactivity of small size particles with sintering atmosphere.