• Journal of the East Asian Society of Dietary Life
• /
• v.23 no.6
• /
• pp.833-838
• /
• 2013

In this study, twelve strains of brewing fungi were individually cultivated on wheat extract broth (WEB), potato dextrose broth (PDB) and malt extract broth (MEB) in order to determine the microorganism with good culture characteristics as well as with amylolytic activity. The strain cultured in PDB exhibited mycelia production from 12.6 g/L (Rhizopus oryzae KACC 45714) to a maximum of 48.0 g/L (Aspergillus oryzae KACC 46959), which was 2.3~9.2 times lower than that of the strain cultured in WEB and 1.7~14.6 times lower than that of the strain cultured in MEB. Accorfing the results, We found that the commercial strains of A. oryzae Suwon, CF1001 and CF1003 had a higher dry cell mass than the wild-type strains KACC 46421, 46423, 46424 and 46959. For Rhizopus sp., the acidity levels in WEB, PDB and MEB were 0.12~0.47%, 0.22~1.0% and 0.16~0.68% (equivalent lactic acid concentration) respectively. For A. oryzae, the acidity levels were 0.06~0.11%, 0.03~0.04% and 0.06~0.08% (equivalent lactic acid concentration), respectively. Amylase enzyme from Rhizopus delemar KACC 46419 exhibited an enzyme activity of 0.013 U and 0.019 U in WEB and MEB cultures, respectively. The enzyme activity of the amylase enzyme from A. oryzae was 0.019~0.037, 0.017~0.033 and 0.028~0.046 U in WEB, PDB and MEB cultures, respectively.

• Journal of Mushroom
• /
• v.20 no.1
• /
• pp.29-33
• /
• 2022

In this study, five different Lentinula edodes cultivar (Chamaram, Sanbaekhyang, Sanjo 713ho, Sanjo 715ho, Sanjo 718ho) were evaluated for their ability to decolorize Remazol Brilliant Blue R (RBBR) in MEB medium, respectively. Chamaram and Sanjo 713ho decolorized RBBR rapidly in MEB medium within 3 and 5 days. The activities of manganese peroxidase (MnP) and laccase were determined on the MEB medium with and without lignin. Sanjo 713ho resulted the highest ligninolytic enzyme activities on incubation day 1, indicating of 1,213 U/mg of MnP activity and 1,421 U/mg of laccase activity.

• Food Science and Preservation
• /
• v.14 no.3
• /
• pp.315-322
• /
• 2007

The patulin producing capicity of Penicillium crustosum, an isolate from Korean apple, in various broth culture media, was investigated, and compared with patulin production by the standard strain P. griseofulvum(ATCC 46037). The maximal patulin production capacity of the P. griseofulvum ATCC 46037 was 2,029-2,829 ppm in 5-GYEP, SY and MEB broth media. The patulin-producing capacity of the isolated fungus(P. crustosum) attained 2,794 ppm in a 5-GYEP broth medium, but was only 324 and 11 ppm in SY and MEB media, respectively. There were no significant correlations between mycelial growth levels and patulin-producing ability in either P. crustosum or P. griseofulvum. The patulin production of P. griseofulvum was induced in the wide pH range of pH 3.0-11.0, while that of P. crustosum was induced in the acidic pH range pH 3.0-5.0. Patulin production levels were dependent on the carbon sources in the media and maximal patulin production by P. griseofulvum and P. crustosum was observed in media containing glycerol and fructose, respectively.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1998.08a
• /
• pp.94.1-94
• /
• 1998

• Korean Journal of Mathematics
• /
• v.31 no.1
• /
• pp.63-73
• /
• 2023

In this paper, we determine all repdigits, which are difference of two Pell and Pell-Lucas numbers. It is shown that the largest repdigit which is difference of two Pell numbers is 99 = 169 - 70 = P₇ - P₆ and the largest repdigit which is difference of two Pell-Lucas numbers is 444 = 478 - 34 = Q₇ - Q₄.

• Honam Mathematical Journal
• /
• v.45 no.4
• /
• pp.572-584
• /
• 2023

In this study, we search for Pell and Pell-Lucas numbers, which are concatenations of two repdigits and find these numbers to be only 12, 29, 70 and 14, 34, 82, respectively. We use Baker's Theory and Baker-Davenport basis reduction method while finding the solutions.

• Journal of Embryo Transfer
• /
• v.14 no.3
• /
• pp.145-153
• /
• 1999

This study was conducted to investigate the effects of vitrification solution and developmental stage on the survival rate of vitrified-thawed human blastocyst embryos. Human blastocyst embryos were cryopreserved by vitrification using EFS and GE solution, and their survival rates were examined after thawing and further culture. EFS solution was consisted of 40% ethylene glycol, 18% Ficoll 70 and 0.3M sucrose. GE solution was consisted of 25% glycerol and 25% ethylene glycol. Embryos were exposed to EFS and GE solution by 2 steps and 3 steps, respectively, and plunged into liquid nitrogen after loading into 0.25ml plastic straws. Blastocysts were classified into 4 groups in accordance with their developmental stage: into 1) EEB, 2) MEB and 3) EdB, of blastocysts developed on day 5, and 4) 6d-Bla(the blastocysts which formed on day 6). The blastocysts at each stage were vitrified by GE solution and cryopreserved in LN2. After thawing them, we examined their survival rates, respectively. The resulted of this study were as follows: 1. The survival rate of blastocysts vitrified by GE solution was 64.4%, significantly higher than that (5.7%) vitrified by EFS solution (P<0.001). 2. When the blastocysts were vitrified by GE solution according to each developmental stage, the survival rates of EEB, MEB, EdB and 6d-Bla were 65.9%, 65.9%, 73.2% and 58.1%, respectively. In conclusion, the cryopreservation of human blastocysts by vitrification is likely to have a marked advantage in terms of cost, work and time as compared to the conventional slow freezing in IVF-ET programs.

• Journal of Korean Society of Transportation
• /
• v.24 no.5 s.91
• /
• pp.123-133
• /
• 2006

Seoul and many large cities in Korea have implemented Median Exclusive Bus Lane(MEB). But exclusive bus lane in the middle of the road caused new contradictions between left turn movement and through bus movement and several signal operation techniques like 'left turn Protected' and 'overlap phase' couldn't be applied in intersections on MEB. We suggest 'Bus-only Signal for median lane technique as solution of these problems This study presents optimum signal time design process and detailed algorithms for intersections where bus-only signals are installed. As a test field. we took Yang-Je intersection where Median Exclusive Bus Lane go through. and have large gap in volume of left turn in main direction. And we verified that revised optimum signal time including overlap phase can reduce average delay time of vehicle through before and after simulation.

• Journal of Life Science
• /
• v.16 no.3 s.76
• /
• pp.477-484
• /
• 2006

This study was performed to know the potentialities of the fruits of Opuntia ficus-indica, as a medium for mushroom mycelial culture. Five mushroom mycelial (Agrocus blazei, Grifola frondosa, Hericium erinaceum, Innonotus obliquus, Phellinus linteus) were frown on the malt extract broth (MEB) and the cactus broth medium (CB). The submerged culture mixtures were extracted using equal volume of ethyl acetate, and their extract yields, total polyphenol contents, and some physiological activities were compared with each other Each extract from mycelial culture grown on CB medium showed remarkable enhancement in physiological activities compared with each counterpart grown on MEB. Among five mycelial cultures grown on CB medium, the extract yield and polyphenyl content were highest in the extract from Grifola frondosa (extract yield, 0.4 g/L and polyphenol content, 22.7%). Also, the extracts from Grifola frondosa showed the highest physiological activities, such as DPPH radical scavenging ($IC_{50}=362.9{\mu}g/ml$), xanthine oxidase inhibition (about 80% at $500{\mu}g/ml$), and superoxide radical scavenging (about 80% at $500{\mu}g/ml$), and NO production inhibition ($IC_{50}=43.1{\mu}g/ml$) in LPS-stimulated RAW 264.7 cells. This result suggests that the fruit of Opuntia ficus-indica can be used as a culture medium for improving the functional properties of various mushroom mycelia.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.10a
• /
• pp.242-247
• /
• 2003

An experimental study presents characteristics of combustion in a combustion chamber by port deactivation valve for economy and emissions standards. In order to use combustion properties data it is necessary to build some data base, which use cylinder pressure sensor, etc. Port deactivation valve has been developed to satisfy requirement of achieving sufficient swirl generation to improve the combustion. A feasibility and necessity of combustion pressure based cylinder spark timing control has been examined. So, this was obtained the Coefficient of Variation(COV) and the mass-burned(MFB). The characteristics of pressure ratio fraction is similar to that of mass-burned fraction. Using the results of the test, the effects of the combustion chamber can be improved combustion stability by port deactivation.