• 산업식품공학
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• 제15권3호
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• pp.214-220
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• 2011

중고압 하에서 $\beta$-glucosidase효소반응을 물리화학적 관점에서 연구하였다. 모델 기질 (p-nitrophenyl-${\beta}$-D-glucopyranoside)에 대한 $\beta$-glucosidase 효소의 작용에 대한 압력 효과를 실험 하였다. 즉, 압력 조건(25MPa, 50 MPa, 75 MPa, 100 MPa)과 시간 (10분, 60분, 1시간, 6시간, 24시간, 40시간)의 처리 조건에서 효소 활성도를 분광학적인 표준방법에 따라 측정하였다. 효소-기질 반응의 단계를 크게 kinetic 구간과 평형 구간으로 구분하여 물리화학적 모델을 적용하여, 정 역반응속도 상수, 평형상수, 압력에 의한 부피 감소 등을 산출하였다. 대기압에서 100MPa까지 압력이 증가할수록 효소-기질 반응의 생성물이 더 많이 형성되었으며 전형적인 kinetic 구간과 평형 구간이 나타났다. 압력, 시간, 생성물농도 등의 데이터로부터 kinetic 구간과 평형에서의 생성물 예측 모델을 완성하였다. 결론적으로 중고압 처리에 의하여 효소-기질 반응이 촉진됨을 알 수 있었고, 임의의 압력 및 시간 조건에 따른 생성물의 농도를 예측할 수 있게 되었다.

• Animal Bioscience
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• 제34권4호
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• pp.558-566
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• 2021

Objective: Objectives were to estimate energy and protein requirements of dairy crossbred steers, as well as to evaluate equations previously described in the literature (HH46 and CS16) to predict the carcass and empty body chemical composition of crossbred dairy cattle. Methods: Thirty-three Holstein×Zebu steers, aged 19±1 months old, with an initial shrunk body weight (BW) of 324±7.7 kg, were randomly divided into three groups: reference group (n = 5), maintenance level (1.17% BW; n = 4), and the remaining 24 steers were randomly allocated to 1 of 4 treatments. Treatments were: intake restricted to 85% of ad libitum feed intake for either 0, 28, 42, or 84 d of an 84-d finishing period. Results: The net energy and the metabolizable protein requirements for maintenance were 0.083 Mcal/EBW0.75/d and 4.40 g/EBW0.75, respectively. The net energy (NEG) and protein (NPG) requirements for growth can be estimated with the following equations: NEG (Mcal/kg EBG) = $0.2973_{({\pm}0.1212)}{\times}EBW^{0.4336_{({\pm}0.1002)}$ and NPG (g/d) = 183.6(±22.5333)×EBG-2.0693(±4.7254)×RE, where EBW, empty BW; EBG, empty body gain; and RE, retained energy. Crude protein (CP) and ether extract (EE) chemical contents in carcass, and all the chemical components in the empty body were precisely and accurately estimated by CS16 equations. However, water content in carcass was better predicted by HH46 equation. Conclusion: The equations proposed in this study can be used for estimating the energy and protein requirements of crossbred dairy steers. The CS16 equations were the best estimator for CP and EE chemical contents in carcass, and all chemical components in the empty body of crossbred dairy steers, whereas water in carcass was better estimated using the HH46 equations.

• Earthquakes and Structures
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• 제21권5호
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• pp.551-562
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• 2021

In this study, the generalized intensity measure (IM) named I_Npg is analyzed. The recently proposed proxy of the spectral shape named N_pg is the base of this intensity measure, which is similar to the traditional N_p based on the spectral shape in terms of pseudo-acceleration; however, in this case the new generalized intensity measure can be defined through other types of spectral shapes such as those obtained with velocity, displacement, input energy, inelastic parameters and so on. It is shown that this IM is able to increase the efficiency in the prediction of nonlinear behavior of structures subjected to earthquake ground motions. For this work, the efficiency of two particular cases (based on acceleration and velocity) of the generalized I_Npg to predict the peak floor acceleration demands on steel frames under 30 earthquake ground motions with respect to the traditional spectral acceleration at first mode of vibration Sa(T₁) is compared. Additionally, a 3D reinforced concrete building and an irregular steel frame is used as a basis for comparison. It is concluded that the use of velocity and acceleration spectral shape increase the efficiency to predict peak floor accelerations in comparison with the traditional and most used around the world spectral acceleration at first mode of vibration.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2008년도 제7회 추계학술대회 및 정기총회
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• pp.118-121
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• 2008

본 연구에서는 정보통신기술을 활용한 미래전 개념인 네트워크 중심전 (NCW: Network Centric Warfare) 수행에 있어서 세계적으로 가장 널리 쓰이고 있는 Link-16의 기술적 요소들을 물리계층, 데이터링크 계층, 응용계층(전술메시지교환) 측면에서 검토하고 작전 운용 측면에서 Link-16 만의 장점과 한계점을 도출해 보기로 한다. 특히, 군용 전술 네트워크인 Link-16의 경우 통신 보안 및 견고성에 시스템 설계상의 주안점이 주어지기 때문에 비록 낮은 전송속도이지만 Link-16의 전송용량의 적절한 분배와 활용 방안은 매우 중요한 문제이다. 본 연구에서는 Link-16의 타임슬롯 구조, NPG 개념, 멀티네팅 개념을 기반으로 주요 작전을 수행하는데 있어서 네트워크 참가요소 (지상 및 공중 플랫폼)에 효율적인 전송용량 배분을 하기 방안을 제시한다. 여기에 있어서 고려해야 할 요소들로는 불필요한 통신용량할당의 최소화, 네트워크 설계 과정의 간소화, 작전 목적에 대한 충분한 지원, 보안성 유지 등을 들 수 있다.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1642-1651
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• 2021

In this study, isophtalic neopentyl glycol polyester (NPG-PES) based composites with different loading ratios of pure tungsten metal (W), tungsten (VI) oxide (WO₃), tungsten boron (WB) and tungsten carbide (WC) composites were prepared as alternative shielding materials for ionizing electromagnetic radiation (IEMR) shielding. Structural characterizations of the composites were done. Gamma spectrometric analysis of composites for 80-2000 keV energy range was performed and their usability as IEMR shielding was discussed. As a result, the produced composites showed a shielding performance of 60-100% of the lead (the most widely used IEMR shielding material) depending on the reinforcement material, reinforcement loading rate and experimental conditions. Thus, it was reported that produced composites could be an alternative to lead shieldings that have several disadvantages as toxic properties, difficulty of processing and inelasticity.

• 생명과학회지
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• 제20권4호
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• pp.487-495
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• 2010

Carboxymethylcellulose (CMC)를 분해하는 미생물을 해수에서 분리하였으며, 16S rDNA의 염기서열을 분석하여 동정한 결과, Psychrobacter aquinaris로 학인 되어 P. aquinaris LBH-10로 명명하였다. 이 균주는 CMC, 셀로바이오스, 커드란, 여과지, p-nitrophenyl-$\beta$-D-glucopyranoside (pNPG), 풀루란 및 자일란을 분해하였으나, avicel 및 섬유소는 분해하지 못하였다. P. aquinaris LBH-10이 생산하는 carboxymethylcellulase (CMCase)의 최적 반응 온도는 $50^{\circ}C$이었으며, $20^{\circ}C$에서 $50^{\circ}C$의 온도 범위에서 24시간이 경과한 후에도 90% 이상의 활성을 유지하였다. 또한, 이 균주가 생산하는 CMCase의 최적 반응 pH는 3.5이었으며 pH 2.5에서 pH 7.0 사이의 산성 조건하에서 24시간이 경과한 후에도 70% 이상의 활성을 유지하였다. P. aquinaris LBH-10이 생산하는 CMCase의 최적 반응 pH는 지금까지 발견된 섬유소 분해효소 중에서 가장 낮은 pH로 판단된다. 제한된 농도의 $CoCl_2$, EDTA, 및 $PbCl_2$은 P. aquinaris LBH-10가 생산하는 CMCase의 활성을 증가시켰으나, $HgCl_2$, KCl, $MnCl_2$, $NiCl_2$, 및 $SrCl_2$는 이 균주가 생산하는 CMCase의 활성을 감소시켰다.

• Journal of Microbiology and Biotechnology
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• 제28권5호
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• pp.757-764
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• 2018

A cellulolytic fungus, YDJ14, was isolated from compost and identified as an Aspergillus sp. strain. Three extracellular ${\beta}$-glucosidases, BGL-A1, BGL-A2, and BGL-A3, were separated using ultrafiltration, ammonium sulfate fractionation, and High-Q chromatography. The molecular masses of the three enzymes were estimated to be 100, 45, and 40 kDa, respectively, by SDS-PAGE. The optimum pH and temperature of BGL-A3 were 5.0 and $50^{\circ}C$, respectively, whereas the optimum pH and temperature of BGL-A1 and BGL-A2 were identical (4.0 and $60^{\circ}C$, respectively). The half-life of BGL-A3 at $70^{\circ}C$ (2.8 min) was shorter than that of BGL-A1 and BGL-A2 (12.1 and 8.8 min, respectively). All three enzymes preferred p-nitrophenyl-${\beta}$-$\text\tiny{D}$-glucopyranoside (pNPG) and hardly hydrolyzed cellobiose, suggesting that these enzymes were aryl ${\beta}$-glucosidases. The $K_m$ of BGL-A3 (1.26 mM) for pNPG was much higher than that of BGL-A1 and BGL-A2 (0.25 and 0.27 mM, respectively). These results suggested that BGL-A1 and BGL-A2 were similar in their enzymatic properties, whereas BGL-A3 differed from the two enzymes. When tilianin (a flavone glycoside of acacetin) was reacted with the three enzymes, the inhibitory activity for monoamine oxidase, a target in the treatment of neurological disorders, was similar to that shown by acacetin. We conclude that these enzymes may be useful in the hydrolysis of flavone glycosides to improve their inhibitory activities.

• 한국식품저장유통학회지
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• 제21권3호
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• pp.442-450
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• 2014

수집한 장류 시료에서 분리한 균주들을 CMC를 함유하는 배지에 접종하여 섬유소 분해 활성이 우수한 4-1 균주를 선발하였다. 4-1 균주의 16S rRNA 염기서열을 분석한 결과, B. subtilis로 동정되었다. B. subtilis 4-1의 효소생산을 위한 최적 배양조건은 탄소원으로 1.0% soluble starch와 질소원으로 0.1% yeast extract를 첨가하여 $45^{\circ}C$에서 24시간 배양하였을 때로 나타났다. 최적 배양 pH를 조사한 결과, pH 5.0~9.0에서 cellulase 효소활성이 높았다. B. subtilis 4-1의 조효소 특성은 효소반응의 최적 pH가 pH 9.0, 반응온도는 $60^{\circ}C$에서 효소활성이 가장 높았으며, $20{\sim}90^{\circ}C$ 온도에서 60분간 열처리시 효소 활성이 80%이상 유지되었다. 따라서 B. subtilis 4-1에 의해 생산되는 cellulase는 내알칼리성 효소로 추정되며, 높은 열에도 안정한 것으로 나타났다. B. subtilis 4-1이 생산하는 cellulase는 CMC에 가장 높은 효소활성을 나타내었으며 avicel과 pNPG에서도 활성을 보여 복합효소로 생각된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권6호
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• pp.404-412
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• 2012

Purpose: The purpose of this study was to evaluate postsurgical facial hard tissue stability after orthognathic surgery with/without posterior impaction in skeletal class III malocclusion patients, and to evaluate the horizontal relapse tendency, according to changes in anteroposterior discrepancy and occlusal planes. Methods: Ninety patients, who had undergone orthognathic surgery in Pusan National University Dental Hospital, were enrolled in this study. Three main groups were classified as follows: Thirty patients underwent mandibular setback bilateral sagittal split ramus osteotomy (BSSRO) only (BSSRO group, BG); another thirty patients underwent mandibular setback BSSRO and Le Fort I osteotomy with posterior impaction (posterior impaction group, PG); and another thirty patients underwent mandibular setback BSSRO and Le Fort I osteotomy without posterior impaction (non-posterior impaction group, NPG). Preoperative (T0), immediate postoperative (T1) and six-month follow-up period (T2) lateral cephalograms were taken, and various parameters were measured. The analyses were done by linear and angular measurements between T0-T1 and T1-T2, to evaluate postsurgical facial hard tissue stability. Results: Mean horizontal relapse rates were distributed from 11.81% to 19.08%, and there were significant postsurgical changes (0.52 mm~2.44 mm) at the B point in all 3 groups. But, there were no statistical differences on relapse rate among BG, PG and NPG patients. Conclusion: In this study, the postsurgical stabilities of BSSRO and Le Fort I osteotomy with/without posterior impaction in skeletal class III malocclusion patients were acceptable. There were no significant statistical differences in mandibular stability according to changes in anteroposterior discrepancy and occlusal planes.

• 생명과학회지
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• 제16권7호
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• pp.1148-1157
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• 2006

초고온성 세균인 Thermotoga maritima로부터 ${\beta}-glucosidase$ 유전자를 클로닝한 후 대장균 숙주에서 발현시켰다. 이 효소는 salicin, arbutin, $_pNPG$과 같은 탄소원의 ${\beta}$-글루코시드 결합을 가수분해하였다. 721개의 아미노산을 암호화하는 2,166 bp의 DNA 염기서열로된 유전자이였다. 다른 ${\beta}-glucosidase$ 효소들과 단백질 유사성을 비교한 결과 glycosyl hydrolase family 3에 속하였으며 MUG-nondenaturing PAGE와 SDS-PAGE에 의해 확인된 단백질의 크기는 약 81 kDa이었다. 효소활성은 pH 7.0, $80^{\circ}C$에서 가장 높은 활성을 나타냈으며 이 효소의 아미노산 서열에 있는 두 개의 아미노산 잔기 (232번 글루탐산과 242번 아스파르트산 잔기)를 알라닌으로 치환시켜 활성이 없어지는 것으로 보아 이 두 잔기가 효소활성에 중요한 역할을 하는 것으로 추정된다.