• Journal of Korean Society of Forest Science
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• v.105 no.3
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• pp.351-359
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• 2016

This study was conducted to analyze the effect of climate change on the tree-ring growth of Pinus koraiensis in Korea. Annual tree-ring growth data of P. koraiensis collected by the $5^{th}$ National Forest Inventory were first organized to analyze yearly growth patterns of the species. When tree-ring growth data were analyzed through cluster analysis based on similarity of climatic conditions, five clusters were identified. Yearly growing degree days and standard precipitation index based on daily mean temperature and precipitation data from 1951 to 2010 were calculated by cluster. Using the information, yearly temperature effect index(TEI) and precipitation effect index(PEI) by cluster were estimated to analyze the effect of climatic conditions on the growth of the species. Tree-ring growth estimation equations by cluster were developed by using the product of yearly TEI and PEI as independent variable. The tree-ring growth estimation equations were applied to the climate change scenarios of RCP 4.5 and RCP 8.5 for predicting the changes in tree-ring growth by cluster of P. koraiensis from 2011 to 2100. The results of this study are expected to provide valuable information necessary for estimating local growth characteristics of P. koraiensis and for predicting changes in tree-ring growth patterns caused by climate change.

• Journal of Environmental Impact Assessment
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• v.26 no.5
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• pp.291-302
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• 2017

The research was carried out in order to find climate factors which determine the distribution of Eurya japonica, and the potential habitats (PHs) under the current climate and climate change scenario by using species distribution models (SDMs). Four climate factors; the warmth index (WI), the minimum temperature of the coldest month (TMC), summer precipitation (PRS), and winter precipitaion (PRW) : were used as independent variables for the model. Seventeen general circulation models under RCP (Representative concentration pathway) 8.5 scenarios were used as future climate scenarios for the 2050s (2040~2069) and 2080s (2070~2099). Highly accurate SDMs were obtained for E. japonica. The model of distribution for E. japonica constructed by SDMs showed that minimum temperature of the coldest month (TMC) is a major climate factor in determining the distribution of E. japonica. The area above the $-5.7^{\circ}C$ of TMC revealed high occurrence probability of the E. japonica. Future PHs for E. japonica were projected to increase respectively by 2.5 times, 3.4 times of current PHs under 2050s and 2080s. It is expected that the potential of E. japonica habitats is expanded gradually. E. japonica is applicable as indicator species for monitoring in the Korean Peninsula. E. japonica is necessary to be monitored of potential habitats.

• Journal of Dairy Science and Biotechnology
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• v.35 no.3
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• pp.202-207
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• 2017

The objective of this study was to analyze the effects of homogenization, storage temperature, and storage period on the creaming of milk fat and changes in fat contents in the upper and lower layers and to predict the conditions for optimal homogenization efficiency using response surface methodology (RSM). The homogenization pressure, storage temperature, and storage period were set as independent variables of RSM, and the dependent variables were creaming, US Public Health Service (USPHS) code, and volume weighted mean diameter ($D_{4,3}$) in the upper and lower layers. Based on the results of RSM and regression analysis, the correlation coefficient ($R^2$) between experimental data and predicted values by RSM for homogenized milk was estimated to be more than 0.8. The RSM analysis indicated that optimal homogenization pressures of 14 MPa or more and 17 MPa or more were required to maintain the creaming layer of 3 mm or less during the storage for 15 days at $10^{\circ}C$ and $20^{\circ}C$, respectively. To keep the USPHS code at less than 10% for 15 days at $10^{\circ}C$ and $20^{\circ}C$, milk should be homogenized with a pressure of 16.8 MPa or more and 17 MPa or more, respectively.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.622-627
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• 2009

The objectives of this study were to evaluate a protease suitable for the enzymatic hydrolysis of a snow crab processing by-product (SPB) and to optimize the hydrolysis conditions using response surface methodology (RSM). The SPB was hydrolyzed at $50^{\circ}C$ and pH 7.0-7.2 to obtain various degree of hydrolysis (DH) using Flavourzyme at an enzyme/substrate (E/S) ratio of 3.0%. The reaction progress curve exhibited an initial fast reaction rate followed by a slowing of the rate. The DH was increased to 30% at 90 min with a final DH 32 to 36%. A central composite experimental design having three independent variables (reaction temperature, reaction time, and E/S ratio) with five levels was used to optimize the enzymatic hydrolysis conditions. Based on the DH data, the optimum reaction conditions for the enzymatic hydrolysis of the SPB were a temperature of $51.8^{\circ}C$, reaction time of 4 hr 45 min, and an E/S ratio of 3.8%. It was demonstrated that the enzymatic hydrolysate of SPB could be used as a flavoring agent or a source of precursors for the production of reaction flavors.

• Korean Journal of Microbiology
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• v.35 no.4
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• pp.258-265
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• 1999

Entry into meiosis in the yeast Saccharomyces cerevisiae is regulated by two major factors: the cell type MATa/MAT${\alpha}$ and the nutriational state (starvation) of the cell. The two independent regulations act through IME1and IME2 expression to initiate meiosis. IME2 encodes a meiosis-specific protein kinase, and it enabled MATa/MAT${\alpha}$ diploid cells to undergo meiosis and sporulation. The PCR mutagenesis method was applied for the isolation of thermosensitive ime2 mutants. Among sixty two mutants isolated from the phenotype of defective spore formation under the restrictive temperature, three with the most easily observed temperature-sensitive phenotype (ts ${\cdot}$ime2-11, ts ${\cdot}$ime2-12 and ts ${\cdot}$ime2-13) were selected for further study. To understand the detailed functions of IME2, we examined the defects of these mutants in the early meiotic pathway including the premeiotic DNA replication and exhibited decreased level in meiotic recombination. These results suggest that the IME2 gene plays essential role in meiotic recombination pathway as well as premeiotic DNA replication. As the result of the IME2 overexpression in ${\Delta}$mre4. moreover, it was suggested that the IME2 and MRE4 genes act on the same pathway of initiation step in meiotic recombination.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.556-561
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• 1997

Vibrio cholerae non-O1 FM-3 was isolated from sea water, and it showed the same bacteriological characteristics as Vibrio cholerae non-O1 ATCC 25872. V. cholerae non-O1 FM-3 presented the highest hemolytic activity at stationary phase of its growth. The hemolytic activity was decreased in accordance with increasing of pretense activity of its cultural supernatant. The characteristics of the hemolysin produced by V. cholerae non-O1 FM-3 were investigated after partial purification with a Sephadex G-100 chromatography. The hemolytic activity of purified protein was stable at $4^{\circ}C$ while it was completely lost by heating at $60^{\circ}C$ for 30 min. The activity of hemolysin was increased by addition of divalent cations such as $Ca^{2+},\;Mg^{2+},\;and\;Mn^{2+}$ while it was inhibited by additions of $Zn^{2+}$. When the hemolysin was incubated with suspensions of erythrocytes at $4^{\circ}C$ and $37^{\circ}C$, respectively, hemolysis was not observed at $4^{\circ}C$ but at $37^{\circ}C$. It means that hemolysis by purified hemolysin was temperature-dependent while its binding step of hemolysin to cell membrane was temperature-independent.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.3
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• pp.193-203
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• 2005

Highly c-axis oriented nanocrystalline ZnO thin films on silica glass substrates were prepared by spin coating-pyrolysis process with a zinc naphthenate precursor. Only the XRD intensity peak of (002) phase was observed for all samples. With an increase in heat treatment temperature, the peak intensity of (002) phase increases. No significant aggregation of particle was present. From scanning probe microscopy analyses, three-dimensional grain growth, which was thought to be due to inhomogeneous substrate surface and c-axis oriented grain growth of the ZnO phase, was independent on heal-treatment temperature. Highly homogeneous surface of the highly-oriented ZnO film was observed at $800^{\circ}C$. All the films exhibited a high transmittance (above 80%) in visible region except film heat treated at $1000^{\circ}C$, and showed a sharp fundamental absorption edge at about $0.38{\sim}0.40{\mu}m$. The estimated energy band gap for all the films were within the range previously reported for films and single crystal. ZnO films, consisting of densely packed grains with smooth surface morphology were obtained by heat treatment at $600^{\circ}C{\sim}800^{\circ}C$, expected to be ideal for practical application, such as transparent conductive film and optical device.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.990-997
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• 1998

In this work, the $SiO_2$ films on the silicon substrate with different orientations were first prepared by the low temperature process using the ECR plasma diffusion as a function of microwave power and oxidation time. Before and after thermal treatment, the surface morphology, Si/O ratio from physicochemical properties, and the electrical properties of the oxide films were also investigated. The oxidation rate increased with microwave power, while surface morphology showed the nonuniform due to etching. The film quality, therefore, was lowered with increasing the defect by etching and the content of positive oxide ions in the oxide films from bulk by higher self-DC bias. The content of positive oxide ions in the oxide films with different Si orientations showed Si(100) < Si(111) < poly Si. The defects in $Si/SiO_2$ interface of $SiO_2$ film could be decreased by annealing, while $Q_{it}$ and $Q_f$ were independent of thermal treatment and the dependent on concentration of reactive oxide ions and self-DC bias of substrate. At microwave power of 300, and 400 W, the high quality $SiO_2$ film that had lower surface roughness and defect in $Si/SiO_2$ interface was obtained. The value of interface trap density, then, was ${\sim}9{\times}10^{10}cm^{-2}eV^{-1}$.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.75-83
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• 2004

Temperature-phased anaerobic digestion (TPAD), anaerobic sequencing batch reactor (ASBR), and co-digestion technologies were combined together in order to overcome low efficiencies of conventional anaerobic sewage sludge digestion processes. In the performance, TPAD-ASBR process showed high VS removal efficiency over 60% up to the organic loading rate (OLR) of 2.7 g VS/L/d. The first-stage of TPAD-ASBR and control system played a most significant role in VS destruction and methane production. Methane production rate (0.79 l $CH_4/L/d$) of the system was higher than that (0.59 l $CH_4/L/d$) of the control system. The substrate characteristics of the sewage sludge, such as low VS concentration (1.5%, w/w) and biodegradability, were properly improved by the addition of food waste as a co-substrate, leading to more efficient VS removal and methane production. With several track studies, it was revealed that the independent solid retention time (SRT) of those systems prevented untreated particles from outflowing and also, extended the retention time of the active biomass for further degradation. Consequently, it was confirmed that the sequencing batch operation of the TPAD process using co-substrate was a promising alternative for the recycling of sewage sludge with low VS content.

• Journal of Applied Biological Chemistry
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• v.54 no.2
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• pp.94-100
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• 2011

A gene encoding a putative phospholipase D was isolated from Bacillus licheniformis and cloned into pGEM-T easy vector. The gene was expressed in E. coli BL21 (DE3) using a pET-21(a) vector containing His6 tag. Affinity purification of the recombinant phospholipase D with nickel-nitrilotriacetic acid (Ni-NTA) resin resulted major one-band by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The purified enzyme showed a molecular weight of 44 kDa. The optimum activity of enzyme was around pH 7.0 and the enzyme was also the most stable around this condition. The optimum temperature was about $40-45^{\circ}C$ and the enzyme still showed considerable activities at wide range of temperature. Among various detergents, Triton X-100 significantly increased the enzyme activity, resulting in 181% activity of control at 0.6 mM of the detergent. Calcium ion did not significantly affect the enzyme activity, suggesting that the enzyme might be classified into $Ca^{2+}$-independent PLD.