• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.292-297
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• 1993

Aspergillus niger No. PFST-38 was grown on complex media in 30L agitated fermentors at various aeration rates and stirrer speeds. We could correlate the mixing time as a function of the Reynolds number and the apparent viscosity, as follows. ${\theta}_M=2.95\;\NRe^{-0.52},\;{\theta}_M=1.88\;{\eta_a}^{0.57}$ Also, the effects of the apparent viscosity (${\theta}_a$), the impeller rotational speed (N), the air flow rate ($V_s$), and the mixing time (${\theta}_M$) on the oxygen transfer coefficient, $K_L a$ were determined experimentally, and equated as follows. $K_La=12.04N^{0.88}Vs^{0.71}{n_a}^{-0.83},\;K_La=30.2N^{0.88}Vs^{0.71}{\theta_M}^{-1.45}$ $K_La$ increased as the agitation speed and the air flow rate increased. The rate of $K_La$ increase was dependent more on the rotational speed of impeller than on the air flow rate. The glucoamylase production increased with the increase of the agitation speed upto at 500 rpm and increased with the increase of air flow rate upto at 1.0 vvm. The values calculated from the above equation confirmed that the experimental maximum production of glucoamylase was achieved when the $K_La$ and the apparent viscosity of the broth were $260\;hr^{-1}$ and 1800 cps, respectively.

• Mycobiology
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• v.51 no.2
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• pp.94-108
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• 2023

Termitomyces sp. that grow in symbiosis with fungus-farming Termites have medicinal properties. However, they are rare in nature, and their artificial culture is challenging. The expression of AXL receptor tyrosine kinase and immune checkpoint molecules favor the growth of cancer cells. The study evaluated the optimal conditions for the artificial culture of Termitomyces and their inhibitory activity on AXL and immune checkpoint molecules in lung adenocarcinoma and melanoma cell lines. The culture of 45 strains of Termitomyces was compared. Five strains with marked growth rates were selected. Four of the selected strains form a single cluster by sequence analysis. The mycelium of 4 selected strains produces more fungal mass in potato dextrose broth than in a mixed media. The bark was the most appropriate solid substrate for Termitomyces mycelia culture. The mycelium of all five selected strains showed a higher growth rate under normal CO₂ conditions. The culture broth, methanol, and ethyl acetate of one selected strain (T-120) inhibited the mRNA relative expression of AXL receptor tyrosine kinase and immune checkpoint molecules in cancer cell lines. Overall, these results suggest the potential usefulness of Termitomyces extracts as a coadjuvant therapy in malignant diseases.

• Journal of Advanced Engineering and Technology
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• v.5 no.4
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• pp.349-353
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• 2012

Recently, Mobile multimedia equipments as smart phone and tablet pc requirement is increasing and this market is also being expanded. These mobile equipments require large multi-media function, so more power consumption is required. For these reasons, the needs of power management IC as switching type dc-dc converter and linear regulator have increased. DC-DC buck converter become more important in power management IC because the operating voltage of VLSI system is very low comparing to lithium-ion battery voltage. There are many people to be concerned about digital DC-DC converter without using external passive device recently. Digital controlled DC-DC converter is essential in mobile application to various external circumstance. This paper proposes the DC-DC Buck Converter using the AVR RISC 8-bit micro-processor control. The designed converter receives the input DC 18-30 [V] and the output voltage of DC-DC Converter changes by the feedback circuit using the A/D conversion function. Duty ratio is adjusted to maintain a constant output voltage 12 [V]. Proposed converter using the micro-processor control was compared to a typical boost converter. As a result, the current loss in the proposed converter was reduced about 10.7%. Input voltage and output voltage can be displayed on the LCD display to see the status of the operation.

• Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.283-293
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• 2024

Mahseer (Tor soro) growth performance tends to be slow, necessitating further development and intensification of cultivation. One way to develop aquaculture intensification is to manipulate cultivation containers to create optimal environmental conditions for the mahseer to grow. This study aimed to examine the body performance and growth performance of mahseer reared in different colored containers. Experimental research with completely randomized design was employed, with four colored container treatments namely treatment A (transparent), B (green), C (blue), and D (black), with four replications in each treatment. Findings indicate that different rearing media colors had significant effect on absolute length (4.68 ± 0.24 cm), absolute weight (1.58 ± 0.35 g), specific growth rate (2.17 ± 0.38%), feed conversion ratio (2.87 ± 0.04), survival rate (100 ± 0.00%), gross energy (3,816 ± 65.05 cal/g), and body proximate. Physiologically, mahseer fish bred using blue and black containers tend to be more resistant to stress.The best body performance and growth performance were observed in the blue and black colored containers.

• Applied Biological Chemistry
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• v.13 no.1
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• pp.97-103
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• 1970

This experiment was carried out to investigate the yeasts for the brewing of soy sauce. The yeasts in the soy sauce koji were isolated and identified. And they were classified by coloring with the treatment of TTC(2, 3, 5 triphenyltetrazolium chloride) agar and counted. The result, obtained was as follows; a) The number of the yeasts in the Koji was increased in process of incubation time: about $97{\times}10^3$ per gram of Koji incubated for 3 days, $135{\times}10^3$ 4 days and $179{\times}10^3$ 5days. b) They were classified as 53.6-71.9 per cent of TTC while yeasts for the most, 5.6-11.1 per cent of red yeasts, 6.8-19.5 per cent of red pink yeasts and 11.1-22.6 per cent of pink yeasts. c) 30 strains of yeasts were isolated from the Koji optionally, and they were identified as 6 genera and 11 species: 5 strains of Saccharomyces rouxii, 2 strains of Saccharomyces fermentati, 1 strain of Saccharomyces rosei, 6 strains of Saccharomyces rosei, 6 strains of Hansenula anomala, 1 strain of Hansenula suaveolens, 6 strains of Pichia polymorpha, 2 strains of Debaryomyces hansenii, 2 strains of Debaryomyces nicotianae, 2 strains of Torulopsis candida 2 strains of Torulopsis sake and 1 strains of Torulopsis sake and 1 strain of Candida pelliculosa. d) The yeasts belonging to Hansenula suaveolens, Hansenula anomala Candida pelliculosa, Debaryomyces nicotianae and Pichia polymorplza were classified as TTC white yeasts, Saccharomyces rouxii and Sacharomyces rosei were red, Saccharomyces fermentati and Debaryomyces hancenii were red pink, and Torulopsis candida and Torulopsis sake were pink. e) Generally the growth of the yeasts isolated were rapid on the media containing none or 10 per cent of sodium chloride but almost restrained on the media containing 15-18 per cent of sodium chloride.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.476-483
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• 1990

In order to investigate hydantoinase-producing strain of the genus Streptomyces, 523 strains of Streptomycee sp. isolated from soils were cultivated in various media and conversion activity of the enzyme was measured to DL-5-phenylhydantoin. A number of strains producing hydantoinase were detected and among them, the strain of Streptomyces sp. Y-183 was selected as a most powerful strain to producing the enzyme. The optimal culture conditions for the production of hydantoinase of the strain were studied, and it was found that almost all hydantoinase activity was produced in the cell fraction. The maximum activity of the enzyme, 17.8 unitstg of dried cells weight, was obtained when the strain was cultured at $30^{\circ}C$ for 72 hr in a medium containing 1.0% of glycerol. 0.5% of yeast extract. 0.5% of soytone, 0.5% of beef extract, 0.6% of KCI, 0.002% of $K_2HP0_4, 0.25% \;of \;CaC0_3, \;0.0002% \; of \; ZnSO_4, \; 0.0002%\; of\; FeS0_4$, and 0.4% of uracil as an inducer, and the pH of culture broth was adjusted ranging from 7.0 to 7.5.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.207-217
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• 1992

In this study, isolated and cultured nitrogen fixed microbes were seeded in the three-phase fluidized bed in which gas, solid and liquid were contacted directly. Input velocity was varied from 8.12 cm/hr to 16.32 cm/hr. And upflow gas pressure was fixed to 80 psi. Return ratios were from 0.2 to 0.6 with the each experimental condition. According to these condition, movement of media, growth of biofilm and removal efficiency were measured. As the results, in case of briquette ash, biofilm was developed to $170{\mu}m$ when velocity was 8.12 cm/hr and return ratio was 0.6. In this condition, COD removal efficiency was 97% and $NH_4$-N removal efficiency was 83%. At the same condition, biofilm thickness of glass bead was $17.59{\mu}m$ and its COD and $NH_4$-N removal efficiency was 83% and 72%. Nitrogen fixed microbes have following characters: it formed dark-brownish sludge, excellent adhesive force, easy solid-liquid separation and low oxygen uptake ratio, but sensitive to DO concentration. Not only it endured shock loading, but required short time to steady state.

• Microbiology and Biotechnology Letters
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• v.8 no.1
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• pp.55-60
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• 1980

Some of the cultural conditions were improved in order to obtain the higher biomass of Lactobacillus bulgaricus NLS-4 which has the higher lactic acid producing activity as well. Among eight media including 11％ non-fat milk medium as a control, the TIP medium was selected. By a batch experiment, the maximum cell concentration could be increased to 1.0$\times$10$^{9}$ cells per $m\ell$ when the organism was grown at 38$^{\circ}C$ for 18 hours with agitation speea of 200 rpm and under the constant level of pH 6.5 con-trolled with 1 N KOH solution in the selected medium. The cell concentration was further increased to 2.3$\times$10$^{9}$ cells per me in the steady state of continuous culture at the dilution rate of 0.17 hr$^{-1}$ for 18 hours.

• Journal of the Korean Magnetics Society
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• v.12 no.2
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• pp.57-63
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• 2002

In order to increase the magnetic properties of a Nd-Fe-B sintered magnet, the general factors including particle size and its distribution, volume fraction of Nd$_2$Fe$_{14}$B phase, degree of alignment of Nd$_2$Fe$_{14}$B grain, oxygen content and grain size etc. should be optimized by controlling the composition of Nd-Fe-B alloy as well as the manufacturing process. In this study, fabrication of the Nd-Fe-B sintered magnet was carried out in a laboratory scale by controlling the composition of Nd-Fe-B alloy and the manufacturing process. The optimum milling condition was found by investigating the milling media, milling time and ball size. The addition of FeGa was effective to increase the coercivity of the Nd-Fe-B sintered magnet. A remanence of 14.4 kG, a coercivity of 9.4 kOe and a maximum energy product of 47 MGOe were obtained from the sintered magnet.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.4
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• pp.504-508
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• 1983

To define the effects of synthetic auxins on rooting from the ginseng stern cutting and the root growth in diameter after the rooting of the cuttings, stern cuttings with palmate leaves obtained from seedlings and 2-year old ginseng plants were planted in rooting media treated with solutions of the synthetic auxins. All the roots induced from the cuttings were adventitious fibrous roots at first, but a few adventitious roots of the cutting were thickened in diameter to over 2 to 3mm at 120 days after cutting and the rest of them disappeared. IBA was the most effective auxin for rooting and root growth in diameter after rooting from the cuttings. The shape of the roots that thickened in diameter could be divided into two types. Both types of thickened roots were fully lignified at 120 days after cutting and those thickened roots did not dry up or die by July of the next year, however no rhyzomes or shoot primodia were induced from them.