• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.281-289
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• 1991

Neurospora crassa (KCTC 6079) produces tyrosinase (EC 1.14.18.1) during sexual differentiation under derepressed conditions in the presence of inducers such as amino acid analogues, antimetabolites or protein synthesis inhibitors. The selection of inducer concentration and induction time as well as inducer type are critical for the optimization of the enzyme production. The best inducer was found to be cycloheximide. Since cycloheximide was toxic to the cells, an optimal inducer concentration and an optimal induction time were determined to maximize the enzyme production from batch cultures. Mathematical models for the cell growth and the enzyme production were proposed and used for process optimization. By optimizing the induction conditions, maximum tyrosinase productivity was increased significantly.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.1
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• pp.27-31
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• 1990

Influences of plant phenolic acids and their possible metabolites(non-phenolic aromatic acids involved) in the rumen on the cellulolytic activity of mixed rumen populations were examined by a simple in vitro culture technique. Initial concentrations of aromatic acids were 1, 5, 10 and 20 mM/l. All the tested aromatic acids reduced microbial cellulose digestion especially at the higher initial concentration. P-Coumaric acid, ferulic acid and cinnamic acid, those having unhydrogenated propenoic side chain were more inhibitory than were 3-phenylpropinic acid and phloretic acid, those having hydrogenated propanoic side chain. Lag-time for cellulose digestion was prolonged by former three acids by 16 h. Apparent reduction in p-coumaric acid concentration was observed at 24 h when cellulose digestion began. Volatile fatty acid productions from cellulose fermentation were shifted by former three aromatic acids to produce more acetate and less propionate. This suggests that the selection of celluloytic organisms was induced by these aromatic acids.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.247-252
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• 2010

The present study has been performed to select the osmotic tolerant lines using polyethylene glycol (PEG 6000) through an in vitro and in vivo mutagensis with a gamma-ray. During the screening, we selected three mutant lines that seemed to confer elevated osmotic tolerance in high concentrations of PEG 6000. Fruits of these mutants (Os-HK101, Os-HK102 and Os-HK103) were increased to sugar concentration, L-glutamine acid, vitamin C content and lycopine content than those of the wild type. Also the chlorophyll contents were few decreased more in the three mutant lines than the WT plants. Our results suggest that the Os-HK101 is characterized as osmotic stress tolerance considering the sugar concentration and lycopine content. It is expected that the result of this study can be used for breeding more competitive species with respect to contents in sugar or functional chemicals from the selected osmotic resistant lines.

• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.909-917
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• 2018

Quercetin and its glycoside derivatives were identified and quantified using high-performance liquid chromatograph (HPLC) and liquid chromatograph/mass spectrometer/mass spectrometer (LC/MS/MS) in the leaves, flowers, and fruits of 22 Malus genotypes. In all genotypes, small amounts of quercetin aglycone were present, with water-soluble glycoside forms were the most abundant in different Malus plant tissues, including quercetin-3-galactoside, quercetin-3-rutinoside, quercetin-3-glucoside, quercetin-3-xyloside, quercetin-3-arabinoside, and quercetin-3-rhamnoside. Among these six quercetin glycosides, quercetin-3-galactoside was the common form in Malus plants, except in the leaves and flowers of M. ceracifolia and M. magdeburgensis, and in the fruits of M. micromalus 'Haihong Fruit', where there was a higher concentration of quercetin3-glucoside. Among the different tissues tested, leaves contained the highest concentration of quercetin and its glycosides, while fruits contained the lowest concentrations of these compounds. Among the genotypes we analyzed, no specific genotype consistently contained the highest concentration of quercetin and its glycoside derivatives. M. domestica 'Honeycrisp' had the highest total compound concentration (approximately $1600mg\;kg^{-1}$), whereas M. hupehensis contained the lowest in its fruits. In contrast, the concentration of total quercetin and its glycosides was more than $5000mg\;kg^{-1}$ in the leaves of eight genotypes and greater than $2500mg\;kg^{-1}$ in the flowers of seven species. In general, the concentration of quercetin and its glycoside derivatives depended on the species and tissue type. These results may provide useful information for the evaluation and selection of edible Malus fruits and the materials for quercetin glycoside extraction.

• Korean Journal of Plant Resources
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• v.17 no.1
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• pp.28-33
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• 2004

This study was conducted to simple transformants selection by herbicide Basta treatment after transformation with Agrobacteium tumefaciens MP90/PAT in hybrid poplar(Populus alba ${\times}$ P. glandulosa No. 3). In preliminary study, we determined that the lethal concentration of herbicide Basta was 1.0mg/L in callus culture, adventitious bud formation and axillary bud elongation experiment. By the treatment of 1.0mg/L Basta, we could be selected the transformed shoots effectively from the various cultures. In addition, the treatment was useful on selection of transformants which are growing in soil pot. Finally, we also confirmed the transformation by PAT assay, Above results show that the herbicide Basta treatment and PAT assay can be a very simple and effective method for the identification of PAT gene transformed hybrid poplar.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.162-167
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• 2002

An automotive wheel bearing is one of the most important components to guarantee the service life of a passenger car. The endurance life of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, bearing geometry, internal clearance and so on. In this paper, we analyze the relation between loads and deformations of wheel bearing units. On the basis of it, we calculate the endurance life of wheel bearing units and suggest a method to determine the initial contact angle to achieve a maximum endurance life with considering stress concentration.

• Korean Journal of Poultry Science
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• v.27 no.2
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• pp.133-153
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• 2000

The egg's interior quality is one of the most important criteria for commercial producers and consumers. Internal quality is complex, including aesthetic factors such as taste, freshness, nutritional and processing values, and the genetic influences upon these upon these factors ranges from none to considerable. The rate of cholesterol synthesis in the hen is very high compared to other animals and humans. Genetic selection, diet drugs and other chemicals can alter cholesterol concentration in the plasma of laying hen, but attempts to manipulate the cholesterol concentration in the egg yolk are generally unsuccessful since the cholesterol can only be changed to a small extent. Factors which may affect the degree of pigmentation of the yolk include the type of xanthophyll and its concentration in the feed, the feed composition, and the health of the hen. Several feed ingredients interact with carotenoid pigment to improve or reduce their deposition rates in yolks. Egg weight is determined by genetics, body size prior to first egg housing density, environmental temperature, lighting program, total feed consumption, calcium, phosphorus, niacin, water, methionine, total sulfur amino acids, energy, linoleic acid, fat and protein levels. Eggs need to be promote levels. Eggs need to be promoted a versatile commodity and new processed egg items need to be developed. Organic eggs are laid by hens which were raised in chemical and drug frdd environments. There are still difficulties in producing these eggs due to the availability of organic poultry feeds and cost of organic grains.

• Journal of Environmental Impact Assessment
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• v.3 no.2
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• pp.33-45
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• 1994

Water quality of Chongju and Daejeon Water Intake Tower Region, embayments in Daechong Reservoir was found to be worse than that of main lake after analysis of water which were sampled during April, July, October in 1993. Concentration of COD and SS at those two water intake tower sites were 2.8-5.6 mg/l and 2.2-3.2 mg/l, higher than that of main lake. T-N concentration of those two sites was 1.1-1.9 mg/l similar to that of main lake, and T-P concentration of those two sites was 0.14-0.18 mg/l, higher than that of main lake. This study used water quality model of embayment which can analyse pollutant loads from stream and surrounding land use, advection, decay, and diffusion transport between embayment and main lake. The model can predict water quality of embayment according to the change of pollutant load, water elevation of embayment, quantity of water intake in order to suggest water quality management. This study suggests embayment water quality management alternatives, 1) construction of waste water treatment facilities at embayment and main lake for the decrease of pollutant loading, 2) water intake at main lake less polluted or eutrophicated than embayment, and 3) outflow elevation selection for polluted hypolimnion water outflow during stratification.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.269-280
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• 2017

One major concern that has occupied the mind of the designers is a structural failure as result of stress concentration in the geometrical discontinuities. Understanding the effective parameters contribute to stress concentration and proper selection of these parameters enables the designer get to a reliable design. In the analysis of perforated isotropic and orthotropic plates, the effective parameters on stress distribution around holes include load angle, curvature radius of the corner of the hole, hole orientation and fiber angle for orthotropic materials. This present paper tries to examine the possible effects of these parameters on stress analysis of infinite perforated plates with central quasi-square hole applying grey wolf optimizer (GWO) inspired by the particular leadership hierarchy and hunting behavior of grey wolves in nature, and also the present study tries to introduce general optimum parameters in order to achieve the minimum amount of stress concentration around this type of hole on isotropic and orthotropic plates. The advantages of grey wolf optimizer are stout, flexible, simple, and easy to be enforced. The used analytical solution is the expansion of Lekhnitskii's solution method. Lekhnitskii applied this method for the stress analysis of anisotropic plates containing circular and elliptical holes. Finite element numerical solution is employed to examine the results of present analytical solution. Results represent that by selecting the aforementioned parameters properly, fewer amounts of stress could be achieved around the hole leading to an increase in load-bearing capacity of the structure.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.2
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• pp.269-274
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• 2005

In this work, analytical bias arising from the gas chromatographic determination of sulfur compounds was evaluated by the application of direct loop injection method to the GC/PFPD detection of four sulfur compounds including H$_{2}$S, CH$_{3}$SH, DMS, and DMDS. For the proper evaluation of analytical uncertainties involved in GC calibration, we employed two comparative techniques of calibration at fxed concentration injection (CFCI) vs calibration at fixed volume injection (CFVI) method. The results of our study indicate that CFCI method exhibits very poor sensitivity due to the matrix effect with varying injection volumes. On the other hand, as CFVI method overcomes such limitation, it can be used to obtain very accurate quantification of S compounds at their high concentration levels above a few to a few tens ppb.