• 동아시아식생활학회지
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• 제5권1호
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• pp.101-107
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• 1995

Staphylococcus aureus, the most salt-tolerant food-borne pathogen, produces enterotoxins which may cause symptoms such as vomiting, diarrhea, nausea, and cramps. Since this bacterium has been able to grow at extremely high osmolarity its identity in foods with low water activity values such as salted or dried foods is of great concern. In this study, the growth of S. aureus at high osmolarity has been studied and the doubling time of S. aureus grown at TSB medium containing 15% NaCl has been found to be increased to 4∼5 hours. The stimulation of proline uptake after exposure of cells to high concentration of both extracellular KCl and sucrose was not increased. Stimulation of proline uptake at these environment only occured when 25mM NaCl was present I transport buffer. In additional experiments, the time required to reach mid-logarithmic phase in defined medium of high osmolarity found to be reduce by the presence of glycine betaine, proline, and choline.

• Journal of Plant Biology
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• 제33권4호
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• pp.271-276
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• 1990

Our study was carried out for plant regeneration via somatic embryogenesis from immature seeds of Bletilla striata. The highest frequency of embryogenic callus formation was obtained from the immature seeds (at 150 days after pollination) cultured on Hyponex and VW medium supplemented with 3 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 mg/l kinetin under the dark condition. Multiple somatic embryos were induced when embryogenic callus was transferred to VW medium without growth regulators under continued illumination. Somatic embryos were observed histologically with scanning electron microscopy. Regeneration of Bletilla striata was obtained from somatic embryos with a well-defined scutellum and coleoptile as well as with one or more shoot primordia and root primordia. We think that these methods for orchid multiplication must be useful to access clonal propagation of orchids.

• 한국가축번식학회지
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• 제18권1호
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• pp.31-37
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• 1994

This study carried out to investigate the effects of cryoprotectants in the medium on the survival rate of rapidly frozen porcine bisected demi-embryos. The porcine bisected demi-embryos following dehydration by cryoprotectants containing sucrose were directly plunged into liquid nitrogen and thawed in 3$0^{\circ}C$ water bath. Survival rate was defined as development rate on in vitro culture or FDA-test. The results are summarized as follows : 1. The survival rates of without-zona pellucida embryos and 2 blastomeres porcine embryos were 10.0 and 7.1%, respectively. The rate of unfrozen blastomeres (20.00%) was significantly higher than that of non-frozen oocytes. 2. The survival rates of with and without-zona pellucida of bisected porcine embryos by micromanipulator were 20.0 and 14.3%, respectively. 3. The developmental rates of with and without-zona pellucida of bisected poricine embryos by micromanipulator were 13.3 and 7.1%, respectively.

• 미생물학회지
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• 제21권3호
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• pp.156-162
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• 1983

Conditions for effcient formation and regeneration of protoplasts of Micromonospora rosaria and Micromonospora purpurea were investigated. The state of inoculm, culture stage and growth in a medium containing partially growth-inhibiting concentration of glycing have significant effects on portoplasting. A high frequency of regeneration (up to 30%) was accomplished with a hypertonic regeneration agar medium defined by Okanishi for Strptomyces. Using the optimal conditions for protroplasting and regeneration, protoplast fusion of auxotrophic M.rosaria was carried out. Polyethylene glycol 1,000 was chosen for fusogenic agent. When signgle auxotrophs were used, the recombinant frequency of auxortrophic markers varied from 1.3 to 3.2%. Using two double auxotrophs, the recombinant frequencies of 0.7-4.3% were obtained. Much lower frequencies(three or more orders of magnitude) were observed by the conventional matings.

• 한국식품영양학회지
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• 제7권1호
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• pp.58-63
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• 1994

Sporulation of Streptomyces griseus NRRL B-2682 occurs at 26~28 hours during incubation while shaking at 3$0^{\circ}C$ in a defined medium. The time of sporulation is the same when the levels of each nutrient is increased ten times. The levels of the carbon, nitrogen and phosphate source are at a high level when sporulation begins. Sporulation of S. griseus B-2682 is clearly not caused by nutrient deprivation. It appears that a clock mechanism is involved instead. Once spores are germinated, the time of sporulation is programmed. Sporulation of S. griseus is repressed by high levels of casein hydrolysate. A study of the effect of individual amino acids revealed that L-valise when added to the normal growth medium causes an inhibition or repression of sporulation without affecting growth.

• 대한임베디드공학회논문지
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• 제4권1호
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• pp.35-41
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• 2009

The H.264/SVC enables network-adaptive video transmission to smart device which uses wireless network. But, quality scalability of H.264/SVC does not consider personal subjective image quality. In addition, its network efficiency also does not optimized because it uses MGS(Medium Grained Scalability) and CGS(Coarse Grained Scalability). Thus, this paper proposed a new scalable ROI algorithm for not only subjective image quality improvement but also network adaptation. To experiment our proposed a scheme, we added designed algorithm to JSVM(Joint Scalable Video Model) open source video codec of H.264/SVC. Experiment was performed according to the pre-defined scenario for simulating various network conditions. Finally, experimental result showed our proposed scalable ROI scheme. It is better than traditional non-selective scheme in subjective video quality.

• Bulletin of the Korean Chemical Society
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• 제9권2호
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• pp.77-80
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• 1988

A suituable choice of supporting electrolyte medium for trace level determinations of chromium(VI) by differential pulse polarography is described. A comparative study suggests that sodium borate buffer is superior to ammonium acetate, ammonium tartrate, and especially to NaF which was recently known to be one of the most proper medium for the purpose. With 0.01 M borate, the best combination of high sensitivity, well-defined base line, and freedom from common interferents was attained. With $5.0{\times}10^{-7}$M Cr(VI), tenfold excesses of Cu(II) and Fe(III), and a five hundred-fold excess of $Cl^-$ do not change the peak current by more than about 1%. And the detection limit was $5.0{\times}10^{-8}$M Cr(VI).

• Geomechanics and Engineering
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• 제15권5호
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• pp.1071-1080
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• 2018

The study of behavior and values of deformations in the geological medium makes the scientific basis of the methodology of synthesis of true values of parameters of its physico-mechanical and density properties taking into account the influence of geodynamic impacts. The segments of continuous variation of homogeneous elastic uniform deformations are determined under overall compression of the medium. The limits of these segments are defined according to the criteria of instability (on geometric form changes and on "internal" instability). Analytical formulae are obtained to calculate current and limiting (critical) values of deformations within the framework of various variants of small and large initial deformations of the non-classically linearized approach of non-linear elastodynamics. The distribution of deformation becomes non-uniform in the medium while the limiting values of deformations are achieved. The proposed analytical formulae are applicable only within homogeneous distribution of deformations. Numerical experiments are carried out for various elastic potentials. It is found that various forms of instability can precede phase transitions and destruction. The influence of these deformation phenomena should be removed while the physico-mechanical and density parameters of the deformed media are determined. In particular, it is necessary to use the formulae proposed in this paper for this purpose.

• 한국유체기계학회 논문집
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• 제9권2호
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• pp.30-38
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• 2006

An aerodynamic design for centrifugal compressor which was applied to medium speed diesel engine has been done. First of all, exact compressor specifications must be defined by accurate engine system matching. This matching program has been developed. Using the meanline prediction method, geometric design and performance curves for compressor were established and verified by comparing three dimensional viscous CFD results. The deviation at the design point was about 2.3%. Combustor has been designed and manufactured for the performance test of medium speed diesel engine turbocharger. Fuel nozzle of combustor was designed and its characteristics was analyzed by PIV and PDPA test equipment. Through these results, spray characteristics were studied and flow coefficient equation was deduced.

• KSBB Journal
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• 제22권5호
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• pp.322-327
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• 2007

Mineral salts in medium usually profoundly influence microorganism growth and protein synthesis. In order to produce microbial transglutaminase (MTG) with a high yield from Streptoverticillium mobaraense, we screened the minerals $CaCl_2,\;CoCl_2,\;FeSO_4,\;ZnSO_4,\;MnSO_4\;and\;CuSO_4$ for MTG fermentation. The results indicated that appropriate $FeSO_4$ concentrations could significantly promote cell growth and stimulate the production of MTG. With 15 mg/L of $FeSO_4$ added to medium, 58% improvements were noted in MTG productivity (2.24 U/mL). NaCl, $CaCl_2,\;and\;CoCl_2$ enhanced MTG productivity by less than 15%, and the optimal concentrations were determined as 1 g/L, 2 g/L, and 30 mg/L respectively. Furthermore, it was determined that 7.5 mg/L of $ZnSO_4$ in medium could augment MTG productivity by 20% and induce the stationary phase for MTG production to a period 24 hr earlier. This basic and novel discovery should result in the development of a good complement to the previously defined culture media for MTG fermentation.