• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.212-217
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• 2004

The gene coding for mannanase from Bacillus subtilis WL-7, a number of glycosyl hydrolase family 26, was hyperexpressed in Escherichia coli. Two recombinant plasmids, pE7MAN and pENS7, were constructed by introducing the complete mannanase gene and the mature mannanase gene lacking N-terminal signal peptide region into a expression vector pET24a(＋), respectively. The level of mannanase produced by E. coli BL21 (DE3) carrying pENS7, which included the mature mannanase gene, was considerably higher than that by E. coli BL21 (DE3)/pE7MAN. Almost mannanase produced by the recombinant E. coli carrying pENS7 at growth temperature of $37^{\circ}C$ existed as inactive enzyme of insoluble form. Growth at temperature below $31^{\circ}C$ increased the soluble fraction of mannanase having catalytic activity in the recombinant E. coli cells. The highest productivity of active mannanase was observed in cell-free extract of the recombinant E. coli grown at growth temperature ranging from $25^{\circ}C$ to $28^{\circ}C$, while mannanase activity per soluble protein of the cell-free extract was highest in the cells grown at $^31{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.18 no.6
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• pp.640-646
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• 1990

We have cloned the cdd gene from E. coli C600 using (cdd-) as a host. From the sequenced promoter region of E=, coli cdd gene which has been determined by Valentin-Hansen P. (1985), we synthesized the 23 mer oligonucleotides corresponding to the transcription initiation region and used as a probe for cloning of the cdd gene by Southern blotting. The isolated fragments in the blotting were introduced to the colony hybridization after transforming it into the E. coli JF611 (cdd-, pyr double mutant), and we identified the hybridized band at 27 kb long. From the original insert of 27 kb fragment in theBamHI site of pBR322, the 5.3 kb fragment containing the cdd gene was isolated by subsequent deletion and subeloning. From the derived plasmid pTK509, further deletion and subcloning were performed and clarified that the cdd gene was located in the 2.1 kb of SaZI/DraI segment in the insert of pTK605. The polypeptide encoded by the cloned DNA was appeared to be a molecular mass of 33,000.

• Journal of Life Science
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• v.27 no.9
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• pp.1003-1010
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• 2017

An open reading frame coding for mannanase predicted from the partial genomic sequence of Paenibacillus woosongensis was cloned into Escherichia coli by polymerase chain reaction amplification, and completely sequenced. This mannanase gene, designated man26AT, consisted of 3,162 nucleotides encoding a polypeptide of 1,053 amino acid residues. Based on the deduced amino acid sequence, Man26AT was identified as a modular enzyme, which included a catalytic domain belonging to the glycosyl hydrolase family 26 and two carbohydrate-binding modules, CBM27 and CBM11. The amino acid sequence of Man26AT was homologous to that of several putative mannanases, with identity of 81% for P. ihumii and identity of less than 57% for other strains of Paenibacillus. A cell-free extract of recombinant E. coli carrying the man26AT gene showed maximal mannanase activity at $55^{\circ}C$ and pH 5.5. The enzyme retained above 80% of maximal activity after preincubation for 1 h at $50^{\circ}C$. Man26AT was comparably active on locust bean gum (LBG), galactomanan, and kojac glucomannan, whereas it did not exhibit activity on carboxymethylcellulose, xylan, or para-nitrophenyl-${\beta}$-mannopyranoside. The common end products liberated from mannooligosaccharides, including mannotriose, mannotetraose, mannopentaose, and mannohexaose, or LBG by Man26AT were mannose, mannobiose, and mannotriose. Mannooligosacchrides larger than mannotriose were found in enzymatic hydrolyzates of LBG and guar gum, respectively. However, Man26AT was unable to hydrolyze mannobiose. Man26AT was intracellularly degraded into at least three active proteins with different molecular masses by zymogram.

• Journal of radiological science and technology
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• v.45 no.5
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• pp.449-455
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• 2022

This study is to present a Geant4 code for the simulation of the absorbed dose distribution given by a medical linac for 6 MV photon beam. The dose distribution was verified by comparison with calculated beam data and beam data measured in water phantom. They were performed for percentage depth dose(PDD) and beam profile of cross-plane for two field sizes of 10 × 10 and 15 × 15 cm². Deviations of a percentage and distance were obtained. In energy spectrum, the mean energy was 1.69 MeV. Results were in agreement with PDD and beam profile of the phantom with a tolerance limit. The differences in the central beam axis data 𝜹₁ for PDD had been less than 2% and in the build up region, these differences increased up to 4.40% for 10 cm square field. The maximum differences of 𝜹₂ for beam profile were calculated with a result of 4.35% and 5.32% for 10 cm, 15 cm square fields, respectively. It can be observed that the difference was below 4% in 𝜹₃ and 𝜹₄. For two field sizes of 𝜹_50-90 and RW₅₀, the results agreed to within 2 mm. The results of the t-test showed that no statistically significant differences were found between the data for PDD of 𝜹₁, p>0.05. A significant difference on PDD was observed for field sizes of 10 × 10 cm², p=0.041. No significant differences were found in the beam profile of 𝜹₃, 𝜹₄, RW₅₀, and 𝜹_50-90. Significant differences on beam profile of 𝜹₂ were observed for field sizes of 10 × 10 cm², p=0.025 and for 15 × 15 cm², p=0.037. This work described the development and reproducibility of Geant4 code for verification of dose distribution.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.10
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• pp.1567-1574
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• 2001

In order to operate an RPV safely it is necessary to keep the pressure-temperature (P-T) limit during the heatup and cooldown process. While the ASME Code provides the P-T limit curve for safe operation, this limit curve has been prepared under conservative assumptions In this paper the effects of conservative assumptions involved in the P-T limit curve specified in the ASME Code Sec. XI were investigated. Three different parameters the crack depth the cladding thickness and the cooling rate, were reviewed based on 3-D finite element analyses. Also the constraint effect on P-T limit curve generation was investigated based on J- T approach. It was shown that the crack depth and the constraint effect change the safe region in P-T limit curve significantly Therefore it is recommended to prepare a more precise P-T limit curve based on finite element analysis to obtain P-T limit for safe operation of an RPV.

• Journal of Radiation Protection and Research
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• v.28 no.2
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• pp.79-85
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• 2003

This study was intended to estimate Hp(10) recommended by the ICRU using the $CaSO_4:Dy,P$ element developed in the KAERI. For the estimation of Hp(10), TL response should be compensated properly through the energy range using filter materials since $CaSO_4:Dy,P$ is of severe photon energy dependent response. Various experiments and computations using Monte Carlo Code were carried out for designing filter satisfying the performance requirements of the ISO related to TL dosimeter. Under the completed filter, the relative response of $CaSO_4:Dy,P$ showed $0.75{\sim}1.0$ for photons in the range of $20{\sim}662keV$. Especially it was possible to reduce the thickness of front filter and simplify the filter combination with rear filter of larger diameter and to considerably improve angular dependence by introducing taper to the filler.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.219-222
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• 2013

The Side Channel attack methods proposed by P.Kocher are mainly used for cryptanalysis different cipher algorithms even though they are claimed to be strongly secured. Those kinds of attacks depend on environment implementation especially on the hardware implementation of the algorithm to the crypto module. side-channel attacks are a type of attack introduced by P.Kocher and is applicable according to each environment or method that is designed. This kind of attack can analyze and also extract important information by reading the binary code data via measurement of changes in electricity(voltage) consumption, running time, error output and sounds. Thus, in this paper, we discuss recent SPA and DPA attacks as well as recent countermeasure techniques.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.10
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• pp.43-48
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• 2010

In general, in order to reduce an initial cell searching time, W-CDMA systems adopt a three-step cell search scheme: slot synchronization, frame synchronization, and primary scrambling code identification. We consider the second step (frame synchronization), in which a coherent detection using P-SCH (primary synchronization channel) is possible. In this paper, we propose a new coherent detection scheme, where a first order recursive filter is used to enhance channel estimation performance. Computer simulation results indicate that the detection performance of the proposed scheme can be robust over large range of frequency offset.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.327-333
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• 2014

Two genes encoding the mannanase of Bacillus sp. YB-1401 and B. amyloliquefaciens YB-1402, which had been isolated at acidic pH as mannanase producers, were each cloned into Escherichia coli, and sequenced. Both mannanase genes consisted of 1,080 nucleotides, encoding polypeptides of 360 amino acid residues. The deduced amino acid sequences of the two mannanase genes differed by four amino acid residues different, and were highly homologous to those of mannanases belonging to the glycosyl hydrolase family 26. Comparison of two mannanases produced from recombinant E. coli indicated that His-tagged mannanase of YB-1402 (HtMAN1402) was more stable than that of YB-1401 at acidic pH and high temperature. In particular, HtMAN1402 retained more than 50% of its activity at pH 3.0 after 4 h of pre-incubation, suggesting the enzyme is a valuable candidate for use as a feed additive. In addition, thermostability of the two mannanases was found to be enhanced by $Ca^{2+}$ ions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.4
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• pp.449-455
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• 2011

Recently, international collaborative research which was organized at Bhabha Atomic Research Centre in India, was conducted to develop for pressure capacity and nonlinear behavior of PHWR 1/4 scale nuclear containment building between experimental test and numerical code. In this paper, a nonlinear finite element analysis was carried out in order to predict ultimate pressure capacity and nonlinear behavior of the 1/4 scale containment building. The 1/4 scale containment building is consisted of basemat, cylinder wall, dome and 4-buttress. For the finite element analysis, commercial program ABAQUS was used. Finite element models including concrete, rebar and tendon have been developed for assessment of ultimate pressure capacity and failure mode for nuclear containment building. From the analysis results, first crack of the concrete, the yielding of the rebar and ultimate capacity pressure occurred at $1.6P_d$(design pressure), $3.36P_d$ and $4.0P_d$, respectively.