• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.215-222
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• 2020

The marine microorganism PX-1, which can hydrolyze xylan, was isolated from coastal sea water of Jeju Island, Korea. Based on the 16S rRNA gene sequence and chemotaxonomy analysis, PX-1 was identified as a species of the genus Aestuariibacter and named Aestuariibacter sp PX-1. From the culture broth of PX-1, an extracellular xylanase was purified to homogeneity through ammonium sulfate precipitation and subsequent adsorption chromatography using insoluble xylan. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography estimated the molecular weight of the purified putative xylanase (XylA) as approximately 64 kDa. XylA showed xylanase activity toward beechwood xylan, with a maximum enzymatic activity at pH 6.0 and 45℃. Through thin-layer chromatographic analysis of the xylan hydrolysate produced by XylA, it was confirmed that XylA is an endo-type xylanase that decomposes xylan into xylose and xyloligosaccharides of various lengths. The K_m and V_max values of XylA for beechwood xylan were 27.78 mM and 78.13 μM/min, respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.1
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• pp.13-19
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• 2014

The feed temperature has an effect on the performance during desalination of seawater by membrane separation. When the permeate flux intends to increase using the waste heat, it is necessary to analyze the effect of feed temperature precisely on the membrane performance. The experiments were carried out to investigate the performance of membranes by varying the seawater temperature from $10^{\circ}C$ to $60^{\circ}C$. The increase of permeate flux with increase of feed temperature was interpreted as the change of water viscosity and the membrane itself. While the increase of permeate flux could be predicted by the viscosity change in case of nanoflitration membrane, there exists 30% difference between the experiment data and the prediction by the viscosity change in case of reverse osmosis (RO) membrane, which seems to be due to 8% decrease of the pore size in 60caused by the contraction of membrane with the increase of temperature. Therefore, the desalination of seawater should be carried out within the range that the elevation of temperature does not cause the alteration of membrane itself even for the purpose of increasing the permeate flux.

• The Korean Journal of Applied Statistics
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• v.28 no.2
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• pp.343-351
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• 2015

We introduce how to fit random effects models via a SRC-Stat statistical package. This package has been developed to fit double hierarchical generalized linear models where mean and dispersion parameters for the variance of random effects and residual variance (overdispersion) can be modeled as random-effect models. The estimates of fixed effects, random effects and variances are calculated by a hierarchical likelihood method. We illustrate the use of our package with practical data-sets.

• Journal of Sericultural and Entomological Science
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• v.49 no.2
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• pp.37-42
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• 2007

Lactoferrin, an ion-binding 80-kDa glycoprotein, has been suggested to have many biologic activities, such as facilitating ion absorption and having antimicrobial and anti-inflammatory effects. Several of these activities are likely to only be facilitated by human lactoferrin because they depend on the binding of human lactoferrin to specific receptor. To produce recombinant human lactoferrin to animal foods using transgenic silkworm, Bombyx mori L, we have cloned and sequenced the cDNA encoding for a human lactoferrin (HLf) from the mRNA in mammary tumor line (GI-101). As a result, the 2.5-kb fragment of HLf gene was cloned with pGEM-T vector and then this fragment was sequenced. In the nucleotide sequence analysis, single open reading frame of the 2,136-bp encoding for a polypeptide of 712 amino acid residues was detected. On the other hand, we constructed a recombinant plasmid(pPT-HLf), containing human lactoferrin gene for germ line transformation of the silkworm using a piggyBac transposon-derived vector. A nonautonomous helper plasmid encodes the piggyBac transposase. Approximately 6.7% of individuals in the G0 silkworms expressed green fluorescent protein (GFP). PCR analyses of GFP-positive silkworms (G0 and G1) revealed that independent insertions occurred frequently. Furthermore, Western blot analysis showed that the recombinant HLf expressed in hemolymph has the same molecular weight (80 kDa) as a native protein. On the basis of these experiments, expression of HLf in next generation of transgenic silkworm is now in process.

• Journal of Life Science
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• v.17 no.12
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• pp.1610-1615
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• 2007

Genus Sorbus is a long lived woody species that is primarily distributed throughout Asia and Europe. This species is regarded as very important herbal medicines in Korea and China. Sorbus commixta is primarily distributed throughout Europe. We evaluated a representative sample of the four taxa with nuclear ribosomal DNA internal transcribed spacer sequences (ITS) to estimate genetic relationships within genus. Aligned nucleotide sequences of the length of ITS1 were nearly constant within genus Sorbus varying from 219 in S. aucuparia to 218 in the rest species. Especially, the 5.8S subunit of all taxa of Sorbus was found to constant of 165 bp nucleotides. However, aligned nucleotide sequences of the length of ITS2 vary from 240 in S. sambucifolia var. pseudogrcilisto 245 in S. aucuparia. Total alignment length is 629 positions, of which 35 are parsimony-informative, 32 variable but parsimony-uninformative, and 552 constant characters. The base furtherance showed the difference to the by a total taxon: an average A and T are 17.7% and G and C are 30.4%, 34.2%, respectively. All the four taxa beginning with conserved base paired triplets emerging from single strand regions (domain I). Noteworthy, in the RNA secondary structure proposed for the three Korean Sorbus taxa RNA transcript ITS2, which shows a remarkedly well-conserved folding (domain II). When compared to the European Sorbus (S. aucuparia) of ITS2. ITS analysis may be useful in germ-plasm classification several taxa of genus Sorbus.

• Journal of Life Science
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• v.17 no.12
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• pp.1729-1733
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• 2007

Brassinolide insensitive associated receptor kinase 1(BAK1) is a critical component that play an important roles in signaling of brassinosteroid biosynthesis. Brassinosteroid-deficient and -insensitive mutants showed the characteristic of dwarf symptom. The nutrient deficient tomato showing stunt phenomenon was selected from soiless cultivation system using modified Sonneveld hydroponic solution. Twenty eight protein spots showing different expression levels compared to the control were isolated from extracts of stunted tomato leaves by 2D PAGE analyses. Significantly down-regulated 6 protein spots out of 28 protein spots were analyzed and sequenced by MALDI-TOF mass spectrometry. The protein spot having pI=4.5 and MW=24 kDa was identified as a signal protein, BAK1, which is directly related to brassinosteroid biosynthesis. In addition, five other protein spots were identified as BCK1, cystein proteinase, sulfutase, peroxidase and zinc finger factor respectively, and they were also signal proteins related to brassinosteroid biosynthesis. Furthermore, amplification of 500bp of BAK1 mRNA by RT-PCR using a primer set of peptide matched regions was inhibited conpared to that of the wild type. The results sugested that the BAK1 might be regulated at the transcription level in response to nutrition applications.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.1
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• pp.80-90
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• 2001

The aim of this study is to develop the methodology which enables to identify the mechanical properties of element such as stress intensity factor by using the AE parameters. Considering the multivariate and nonlinear properties of AE parameters such as ringdown count, rise time, energy, event duration and peak amplitude from fatigue cracks of machine element the principal component regression(PCR) and artificial neural network(ANN) models for the estimation of stress intensity factor were developed and validated. The AE parameters were found to be very significant to estimate the stress intensity factor. Since the statistical values including correlation coefficients, standard mr of calibration, standard error of prediction and bias were stable, the PCR and ANN models for stress intensity factor were very robust. The performance of ANN model for unknown data of stress intensity factor was better than that of PCR model.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.94-110
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• 2003

This study utilizes the dataset of Topex/Poseidon(T/P) altimeter sea surface height (1992-2000 yr., 286 cycles)to investigate the tempore-spatial variability in the East (Japan) Sea. Optimal interpolation (Ol) technique was applied to the pre-processed T/P dataset (level 2) to produce sea surface height anomaly (SSHA) map on regular grids. Spectral analyses of the timeseries of the SSHA at chosen stations and empirical orthogonal function (EOF) analysis of the SSHA in the entire East Sea were made. Distribution of the SSHA can be divided by the southern and northern regions sharply by the polar front situated in the middle of the East Sea. The southern region under the direct influence of the Tsushima Current exhibits higher amplitude of the SSHA fluctuation, while the northern region does relatively smaller one. The spatio-temporal variability of the SSHA in the East Sea can be characterized by the five modes of the EOFs accounting for more than 85% of the total variance. The first mode dominates the SSHA variation in the entire domain with strong seasonal and inter-annual periods accounting for the 72.3% of the total variance. The other modes (up to 5th account for 14%) are responsible for the SSHA variation associated with the local current system, meandering of the polar frontal axis, and mesoscale eddies. Spectral peaks with significant confluence level show semi-annual, annual and interannual (2, 3-4 years) periods.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1244-1250
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• 2000

A method for simultaneous quantitative determination of plasticizers such as diethyl phthalate(DEP), di-n-propyl phthalate(DprP), di-n-butyl phthalate(DBP), di-n-pentyl phthalate(DPP), butylbenzyl phthalate(BBP), di-(2-ethylhexyl) phthalate(DEHP), dicyclohexyl phthalate(DCHP) and di-(2-ethylhexyl) adipate(DEHA), which are suspected as endocrine disruptors, in food was studied. A analysis method was optimized for the quantification of plasticizers in Jjambbong, which is a kind of fatty noodle, by using GC/FID. The detection limits of DEP, DprP, DBP, DPP, BBP, DEHP, DCHP and DEHA were 3.5, 5.3, 2.2, 2.2, 7.2, 1.7, 1.9 and 3.0 mg/kg, respectively. Much higher recovery was obtained by extraction with acetone/n-hexane(1:1) rather than hexane solvent system. The recovery of DEP, DprP, DBP, DPP, BBP, DEHP, DCHP and DEHA were 72.7, 85.9, 91.4, 97.1, 100.8, 103.2, 104.3 and 95.8% after 4 time extractions, respectively. The migration of plasticizers from PVC wraps into PVC wrap covered Jjambbong was conducted after shaking(120 rpm) for 30min at room temperature with chosen solvent system. It was found that the migration level of DEHA were 577, 706, 770 mg/kg into Jjambbong, respectively, while the other plasticizers were not observed.

• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.451-462
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• 2005

In order to examine the extent of environmental contamination at abandoned Samsanjeil Cu mines in Kosung-kun, Kyeongsangnam-do, we have investigated the contaminations and mobility of toxic trace elements from mine wastes including about 280,000 tonnages of tailings by chemical experiments (total extraction, partial extraction by 0.1N HCI and sequential extraction procedure). Total concentrations of trace elements showed that Cu, As, Co, Zn, Pb, and Cd concentrations in tailings were 14.0, 3.6, 3.1, 2.1, 2.1 and 1.6 times greater than those in background soil, respectively. From the proportion of metals bound to the exchangeable and carbonate fractions, the comparative mobility of metals decrease in order of $Zn(29.0\%)>Cu(12.3\%)Pb(9.6\%)>Cd(3.0\%)>As=Co(0.0\%)$. Based on the concentrations, chemical speciations of tailings, waste rock and nearby soil, it was revealed that Cu and Zn were the most possible elements to contaminate the surrounding environment in Samsanjeil mine area. In addition, the tailings had total trace metal concentrations below Dutch guideline values except Cu, and they might not affect adverse impact on environment.