• Journal of Microbiology
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• v.43 no.3
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• pp.237-243
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• 2005

The protease purified from Bacillus cereus JH108 has the function of leucine specific endopeptidase. When measured by hydrolysis of synthetic substrate (N-succinyl-Ala-Ala-Pro-Leu-p-nitroanilide), the enzyme activity exhibited optimal activity at pH 9.0, $60^{\circ}C$. The endopeptidase activity was stimulated by $Ca^{++},\;Co^{++},\;Mn^{++},\;Mg^{++},\;and\;Ni^{++}$, and was inhibited by metal chelating agents such as EDTA, 1,10-phenanthroline, and EGTA. Addition of serine protease inhibitor, PMSF, resulted in the elimination of the activity. The endopeptidase activity was fully recovered from the inhibition of EDTA by the addition of 1 mM $Ca^{++}$, and was partially restored by $Co^{++}\;and\;Mn^{++}$, indicating that the enzyme was stabilized and activated by divalent cations and has a serine residue at the active site. Addition of $Ca^{++}$ increased the pH and heat stability of endopeptidase activity. These results show that endopeptidase requires calcium ions for activity and/or stability. A Lineweaver-Burk plot analysis indicated that the $K_m$ value of endopeptidase is 0.315 mM and $V_{max}$ is 0.222 ) is $0.222\;{\mu}mol$ of N-succinyl-Ala-Ala-Pro-Leu-p-nitroanilide per min. Bestatin was shown to act as a competitive inhibitor to the endopeptidase activity.

• Smart Structures and Systems
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• v.26 no.4
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• pp.419-433
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• 2020

Investigation of structural integrity has been a critical issue in the field of civil engineering for years. Visual inspection is one of the most available methods to explore deteriorative components in structures. Still, this method is not applicable to invisible damage of structures. Alternatively, system identification methods are capable of tracking modal properties of structures over time. The deviation of these dynamic properties can serve as indicators to access structural integrity. In this study, a modal tracking technique using frequency-domain system identification from seismic responses of structures is proposed. The method first segments the measured signals into overlapped sequential portions and then establishes multiple Hankel matrices. Each Hankel matrix is then converted to the frequency domain, and a temporal-average frequency-domain Hankel matrix can be calculated. This study also proposes the frequency band selection that can divide the frequency-domain Hankel matrix into several portions in accordance with referenced natural frequencies. Once these referenced natural frequencies are unavailable, the first few right singular vectors by the singular value decomposition can offer these references. Finally, the frequency-domain stochastic subspace identification tracks the natural frequencies and mode shapes of structures through quick stabilization diagrams. To evaluate performance of the proposed method, a numerical study is carried out. Moreover, the long-term monitoring strong motion records at a specific site are exploited to assess the tracking performance. As seen in results, the proposed method is capable of tracking modal properties through seismic responses of structures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.379-380
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• 2008

Molecular Dynamics (MD) simulations have been used to model the dynamics of the charge-compensating sodium ions in the non-stoichiometric hollandite Nax$(Ti_{8-x}Cr_x)O_{16}$. These interstitial ions reside in 'tunnels' in the crystal structure and move under the forces of both the ions making up the cage structure and the many body interactions of the other sodium ions in the tunnel. The Velocity Autocorrelation Function (VAF) of the sodium ions is calculated for a range of temperature from 250K to 1000K and converted into the linear ac-conductivity and ac-susceptibility response via Fourier transformation. A peak is found in the conductivity around $6\times10^{12}$ Hz that has some of the character of a Poley absorption. Here it is shown to be due to an harmonically coupled site vibrations of the sodium atoms, which extend only over a limited range. At frequencies below the peak the conductivity tends towards a constant i.e. dc value corresponding to a constant flow of ions through the simulation cell. At high temperatures the conductivity due to this ion transport process behaves like a metal with an insulator to metal transition occurring around a specific temperature.

• BMB Reports
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• v.37 no.2
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• pp.167-176
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• 2004

Although efficient antiviral lamivudine is used for HBV-infected patients, a prolonged treatment with nucleoside analogs often results in lamivudine-resistant variants. In this study, we evaluated the fidelity of the lamivudine-resistant variants. The FLAG-tagged wild-type (FPolE) and Met550 variants (FPolE/M550A, M550V, and M550I) of HBV DNA polymerases were expressed in insect cells then purified. Like many other reverse transcriptases, no $3'{\rightarrow}5'$ exonuclease activity was detected in the HBV DNA polymerase. Since there is no proofreading activity, then the use of the site-specific nucleotide misincorporation method is beneficial. From the $f_{ins}$ value analysis, it is evident that M550I and M550V exhibit higher fidelity values than the wild-type HBV DNA polymerase, while M550A exhibits similar fidelity values. It is therefore suggested that lamivudine resistance comes from the stringency to dNTP binding and the discrimination of dCTP and lamivudine in M550V and M550I.

• Korean Journal of Food Science and Technology
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• v.11 no.3
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• pp.176-181
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• 1979

Mercury and cadmium concentrations were analyzed for 112 brown rice samples collected from various production areas of Korea in 1976 and the results obtained were as follows: 1) Mercury concentrations were found in the range of non-detectable to 0.310 ppm, with an average of 0.053 ppm for the whole samples. Two samples from Kimpo area showed $5{\sim}6$ times higher concentrations than the average value. 2) Cadmium concentrations were found in range of trace to 0.029 ppm, with an average of 0.021 ppm for the whole samples. No specific site was found to be seriously contaminated by cadmium as far as the present survey was concerned.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.838-844
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• 2001

The enzyme Fuc aldolase from Methanococcus jannaschii that catalyzes the aldol condensation of DHAP and L-lactaldehyde to give fuculose-1-phosphate was inactivated by DEP. The inactivation was pseudo first-order in the enzyme and DEP, which was biphasic. A pseudo second-order rate constant of 120$M^{-1}min^{-1}$ was obtained at pH 6.0 and $25{\circ}C$. Quantifying the increase in absorbance at 240nm showed that four histidine residues per subunit were modified during the nearly complete inactivation. The statistical analysis and the time course of the modification suggested that two or three histidine residues were essential for activity. The rate of inactivation was dependent on the pH, and the pH inactivation data implied the involvement of the amino acid residue with a $pK_a$ value of 5.7. Fuc aldolase was protected against DEP inactivation by DHAP, indicating that the histidine residues were located at the active site of Fuc aldolase. DL-Glyceraldehyde, as an alternative substrate to L-lactaldehyde, showed no specific protection for the Fuc aldolase.

• Geomechanics and Engineering
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• v.28 no.5
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• pp.463-475
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• 2022

In the mine exploitation stage; one of the critical issues is the stability assessment of post-pillars. The instability of post-pillars leads to serious safety hazards in mining operations. The focus of this study is to assess the stability of post-pillars in the 130# stope in the central ore body at Trepça hard rock mine by employing both conventional (i.e., critical span curve) and numerical methods (i.e., FLAC3D). Moreover, a new numerical based index (i.e., Pillar Yield Ratio-PYR) was proposed. The aim of PYR index is to determine a border line between stable, potentially unstable, and failure state of post-pillars at a specific mine site. The critical value of pillar width to height ratio is 2.5 for deep production stopes (e.g., > 800 m). Results showed that pillar size, mining height and mining depth significantly have affected the post-pillar stability. The reliability of numerical based index (i.e., PYR) is verified based on empirical underground pillar stability graph developed by Lunder, 1994. The proposed pillar yield ratio index and pillar stability graph can be used as a design tool in new mining areas at Trepça hard rock mine and for other situations with similar geotechnical conditions.

• Wind and Structures
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• v.38 no.4
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• pp.309-323
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• 2024

The gust factor and turbulence intensity are two crucial parameters that characterize the properties of turbulence. In tropical cyclones (TCs), these parameters exhibit significant variability, yet there is a lack of established formulas to account for their probabilistic characteristics with consideration of their inherent connection. On this condition, a probabilistic analysis of gust factors and turbulence intensities of TCs is conducted based on fourteen sets of wind data collected at the Sutong Cable-stayed Bridge site. Initially, the turbulence intensities and gust factors of recorded data are computed, followed by an analysis of their probability densities across different ranges categorized by mean wind speed. The Gaussian, lognormal, and generalized extreme value (GEV) distributions are employed to fit the measured probability densities, with subsequent evaluation of their effectiveness. The Gumbel distribution, which is a specific instance of the GEV distribution, has been identified as an optimal choice for probabilistic characterizations of turbulence intensity and gust factor in TCs. The corresponding empirical models are then established through curve fitting. By utilizing the Gumbel distribution as a template, the nexus between the probability density functions of turbulence intensity and gust factor is built, leading to the development of a generalized probabilistic model that statistically describe turbulence intensity and gust factor in TCs. Finally, these empirical models are validated using measured data and compared with suggestions recommended by specifications.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.39 no.4
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• pp.38-49
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• 2021

The maintenance project of the Jeonglimsa temple site started with the objective of restoring the original structure of the temple, however, it was gradually transitioned to a landscaping maintenance project over time that constructs a landscape of the temple area. With paying attention to these facts, this study summarized the characteristics of cultural heritage landscaping of the Jeonglimsa temple site as follows. First, Cultural heritage landscaping is a landscaping act that creates, maintains, and manages landscapes within the spatial scope of the cultural heritage designated under the Cultural Heritage Protection Act and the cultural heritage protection area established around it. It is a work that includes protection and maintenance of the excavated remains, spaces by each function and plans for moving lines, Installation of structures to protect cultural properties, adoption of the facilities and structures for convenience of visitors, and construction of vegetation landscape. Second, the cultural heritage landscaping of the Jeonglimsa temple site has been developed in 5 periods, and these include 'the period of historical site investigation' that the temple name was identified through the designation of cultural assets and excavation investigation by the Japanese rule, 'the construction period of Baekje Tower Park' after the liberation from the Japanese rule, 'the period of Baekje Cultural Area Development Project' designated as a historical site, 'the period of the Comprehensive Development Project for a Specific Area of Baekje Culture',which was proceeded with the establishment of the park and museum instead of restoring the temple building due to the difficulty in gathering the pieces of historical evidence, and 'the period of the Jeonglimsa temple site restoring project', which was designated as a World Heritage Site while restoring the buildings deployment in the Buddhist temple at the time of foundation era of Baekje Dynasty. Third, this study verified the landscape changes of the Jeonglimsa temple site that have been transitioned, for instance, the creation of a commemorative park linked to the outer garden of Buyeo Shrine, the implementation of urban planning of the Japanese colonial era, the creation of a protective environment for the excavated historical structures and temple area, the restoration of building deployment in the Buddhist temple, and the sincerity restoration and utilization of cultural assets. Fourth, the landscape of Jeongnimsa temple site is determined by the subject and scope of cultural property designation, land use, movement lines and pavement, repairing methods of remains, structures, facilities, and vegetation. The characteristics of the cultural heritage landscape of Jeongnimsa Temple were derived, such as creating a procedural landscape considering the expansion of the cultural heritage designation scope, securing authenticity by maintaining relics in consideration of reversibility, creating a vegetative landscape suitable for historical and cultural landscapes, and enhancing the value of cultural heritage enjoyment by providing an open space.

• Journal of Cardiovascular Imaging
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• v.30 no.4
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• pp.292-304
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• 2022

BACKGROUND: Calcium is a determinant of paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI). This is based on a fixed contrast attenuation value while X-ray attenuation is patient-dependent and without considering frame expansion and PVL location. We examined the role of calcium in (site-specific) PVL after TAVI using a patient-specific contrast attenuation coefficient combined with frame expansion. METHODS: 57 patients were included with baseline CT, post-TAVI transthoracic echocardiography and rotational angiography (R-angio). Calcium load was assessed using a patient-specific contrast attenuation coefficient. Baseline CT and post-TAVI R-angio were fused to assess frame expansion. PVL was assessed by a core lab. RESULTS: Overall, the highest calcium load was at the non-coronary-cusp-region (NCR, 436 mm³) vs. the right-coronary-cusp-region (RCR, 233 mm³) and the left-coronary-cusp-region (LCR, 244 mm³), p < 0.001. Calcium load was higher in patients with vs. without PVL (1,137 vs. 742 mm³, p = 0.012) and was an independent predictor of PVL (odds ratio, 4.83, p = 0.004). PVL was seen most often in the LCR (39% vs. 21% [RCR] and 19% [NCR]). The degree of frame expansion was 71% at the NCR, 70% at the RCR and 74% at the LCR without difference between patients with or without PVL. CONCLUSIONS: Calcium load was higher in patients with PVL and was an independent predictor of PVL. While calcium was predominantly seen at the NCR, PVL was most often at the LCR. These findings indicate that in addition to calcium, specific anatomic features play a role in PVL after TAVI.