• Food Engineering Progress
• /
• v.15 no.3
• /
• pp.214-220
• /
• 2011

$\beta$-Glucosidase enzyme reaction under high hydrostatic pressure was investigated in terms of physical chemistry. A model substrate (p-nitrophenyl-${\beta}$-D-glucopyranoside(pNPG)) was used, and the pressure effects on the enzymatic hydrolysis (pNPG${\rightarrow}$pNP) at 25 MPa, 50 MPa, 75 MPa, and 100 MPa were analyzed. Two parts of the reaction such as kinetic and equilibrium stages were considered for mathematical modelling, and their physicochemical parameters such as forward and inverse reaction constants, equilibrium constant, volume change by pressure, etc. were mathematically modeled. The product concentration increased with pressure, and the two stages of reaction were observed. Prediction models were derived to numerically compute the product concentrations according to reaction time over kinetic to equilibrium stages under high pressure condition. Conclusively, the $\beta$-Glucosidase enzyme reaction could be activated by pressurization within 100 MPa, and the developed models were very successful in their prediction.

• Animal Bioscience
• /
• v.34 no.4
• /
• pp.558-566
• /
• 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
• /
• v.21 no.5
• /
• pp.551-562
• /
• 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
• /
• 2008.11a
• /
• pp.118-121
• /
• 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
• /
• v.53 no.5
• /
• pp.1642-1651
• /
• 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.

• Journal of Life Science
• /
• v.20 no.4
• /
• pp.487-495
• /
• 2010

A microorganism hydrolyzing carboxymethylcellulose (CMC) was isolated from seawater, identified as Psychrobacter aquimaris by analysis of 16S rDNA sequences, and named P. aquimari LBH-10. This strain produced an acidic carboxymethylcellulase (CMCase), which hydrolyzed carboxymethylcellulose (CMC), cellobiose, curdlan, filter paper, p-nitrophenyl-$\beta$-D-glucopyranoside (pNPG), pullulan, and xylan, but there was no detectable activity on avicel and cellulose. The optimal temperature for CMCase produced by P. aquimari LBH-10 was $50^{\circ}C$ and more than 90% of its original activity was maintained at broad temperatures ranging from 20 to $50^{\circ}C$ after 24 hr. The optimal pH of the CMCase was 3.5, and more than 70% of its original activity was maintained under acidic conditions between pH 2.5 and 7.0 at $50^{\circ}C$ after 24 hr. The optimal pH of CMCase produced by P. aquimaris LBH-10 seems to be lower than those produced by any other bacterial and fungal strain. $CoCl_2$, EDTA, and $PbCl_2$ at a concentration of 0.1 M enhanced CMCase-produced P. aquimaris LBH-10, whereas $HgCl_2$, KCl, $MnCl_2$, $NiCl_2$, and $SrCl_2$ inhibited it.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.5
• /
• pp.757-764
• /
• 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.

• Food Science and Preservation
• /
• v.21 no.3
• /
• pp.442-450
• /
• 2014

In this study, we isolated a cellulase-producing bacterium isolated from traditional Korean fermented soybean paste and investigated the effect of culture conditions on the production of cellulase. This bacterium, which was identified as Bacillus subtilis 4-1 through 16S rRNA gene sequence analysis, showed the highest cellulase activity when the cells were grown at $45^{\circ}C$ for 24 hours in the CMC medium supplemented with 1.0% of soluble starch and 0.1% yeast extract. The initial optimum pH of the medium was observed in the range of 5.0~9.0. The optimal pH and temperature for the production of cellulase from B. subtilis 4-1 were pH 9.0 and $60^{\circ}C$ respectively. In addition, the enzyme showed significant activity in the temperature range of $20{\sim}90^{\circ}C$, which indicates that B. subtilis 4-1 cellulase is an alkaline-resistance and thermo-stable enzyme. This enzyme showed higher activity with CMC as the substrate for endo-type cellulase than avicel or pNPG as the exo-type substrates for exo-type cellulase and ${\beta}$-glucosidase. These results suggest that the cellulase produced from B. subtilis 4-1 is a complex enzyme rather than a mono-enzyme.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.34 no.6
• /
• pp.404-412
• /
• 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.

• Journal of Life Science
• /
• v.16 no.7 s.80
• /
• pp.1148-1157
• /
• 2006

A hyperthermophilic bacterium Thernotoga maritima produced thermostable ${\beta}-glucosidase$. The gene encoding ${\beta}-glucosidase$ from T. maritima MSB8 was cloned and expressed in Escherichia coli. The en-zyme (BgIB) hydrolyzed ${\beta}-glucosidase$ linkages between glucose and alkyl, aryl of saccharide groups such as salicin, arbutin, and $_pNPG$. The insert DNA contained ORF with 2,166 bp encodes a 721 amino acids (calculated molecular mass of 80,964 and pl of 4.93). The amino a.id sequence of BglB showed the similarity to family 3 glycosyl hydrolases. The molecular weight of the enzyme was estimated to be approximately 81kDa by MUG-nondenaturing PAGE (4-methylumbelliferyl 13-D-glucoside-nondenaturing polyacrylamide gel electophoresis) and SDS-PACE. The ${\beta}-glucosidase$ exhibited maximal activity at pH 7.0 and $80^{\circ}C$. By exchanging two possible residues (Glu-232 and Asp-242) to Ala by site-directed mutagenesis method, it was found that these were essential for enzymatic activity.