• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.137-143
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• 1993

The tetranuclear heterometallic complex CpMo$Os_3(CO)_{10}({\mu]-H)2[{\mu}3-{\eta}^2-C(O)CH_2Tol]\;(1,\;Cp={\eta}^5-C_5H_5,\;Tol=p-C_6H_4Me)$ has been examined by variable-temperature $^{13}$C-NMR spectroscopy and by a full three-dimensional X-ray structual analysis. Complex 1 crystallizes in the orthorhombic space group Pna2$_1$ with a = 12.960(1) ${\AA}$, b = 11.255(l) ${\AA}$, c = 38.569(10)${\AA}$, V = 5626(2) ${\AA}^3$ and ${\rho}$(calcd) = 2.71 gcm$^{-3}$ for Z = 8 and molecular weight 1146.9. Diffraction data were collectedon a CAD4 diffractometer, and the structure was refined to $R_F$ = 9.7% and $R_{W^F}$ = 9.9% for 2530 data (MoK${\alpha}$ radiation). There are two essentially equivalent molecules in the crystallographic asymmetric unit. The tetranuclear molecule contains a triangulated rhomboidal arrangement of metal atoms with Os(2) and Mo at the two bridgehead positions. The metal framework is planar; the dihedral angle between Os(l)-Os(2)-Mo and Os(3)-Os(2)-Mo planes is 180$^{\circ}$. A triply bridging (${\mu}_3,\;{\eta}^2$) acyl ligand lies above the Os(l)-Os(2)-Mo plane; the oxygen atom spans the two bridgehead positions, while the carbon atom spans one bridgehead position and an acute apical position. The molecular architecture is completed by an ${\eta}^5$-cyclopentadienyl ligand and a semi-triply bridging carbonyl ligand on the molybdenum atom, and nine terminal carbonyl ligands-four on Os(3), three on Os(l), and two on Os(2). The two hydride ligands are inferred to occupy the Os(l)-Os(2) and Mo-Os(3) edges from structural and NMR data.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.884-894
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• 2023

Design and safety assessment of fuel pins for application in innovative Generation IV fast reactors calls for a dedicated nuclear fuel modelling and for the extension of the fuel performance code capabilities to the envisaged materials and irradiation conditions. In the INSPYRE Project, comprehensive and physics-based models for the thermal-mechanical properties of U-Pu mixed-oxide (MOX) fuels and for fission gas behaviour were developed and implemented in the European fuel performance codes GERMINAL, MACROS and TRANSURANUS. As a follow-up to the assessment of the reference code versions ("pre-INSPYRE", NET 53 (2021) 3367-3378), this work presents the integral validation and benchmark of the code versions extended in INSPYRE ("post-INSPYRE") against two pins from the SUPERFACT-1 fast reactor irradiation experiment. The post-INSPYRE simulation results are compared to the available integral and local data from post-irradiation examinations, and benchmarked on the evolution during irradiation of quantities of engineering interest (e.g., fuel central temperature, fission gas release). The comparison with the pre-INSPYRE results is reported to evaluate the impact of the novel models on the predicted pin performance. The outcome represents a step forward towards the description of fuel behaviour in fast reactor irradiation conditions, and allows the identification of the main remaining gaps.

• Progress in Medical Physics
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• v.33 no.1
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• pp.1-9
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• 2022

Purpose: To evaluate the effective volume of the Korea Research Institute of Standards and Science free air chamber (KRISS FAC) L1 used for the primary standard device of the low-energy X-ray air kerma. Methods: The mechanical dimensions were measured using a 3-dimensional coordinate measuring machine (3-d CMM, Model UMM 500, Carl Zeiss). The diameter of the diaphragm was measured by a ring gauge calibrator (Model KRISS-DM1, KRISS). The elongation of the collector length due to electric field distortion was determined from the capacitance measurement of the KRISS FAC considering the result of the finite element method (FEM) analysis using the code QuickField v6.4. Results: The measured length of the collector was 15.8003±0.0014 mm with a 68% confidence level (k=1). The aperture diameter of the diaphragm was 10.0021±0.0002 mm (k=1). The mechanical measurement volume of the KRISS FAC L1 was 1.2415±0.0006 cm³ (k=1). The elongated length of the collector due to the electric field distortion was 0.170±0.021 mm. Considering the elongated length, the effective measurement volume of the KRISS FAC L1 was 1.2548±0.0019 cm³(k=1). Conclusions: The effective volume of the KRISS FAC L1 was determined from the mechanically measured value by adding the elongated volume due to the electric field distortion in the FAC. The effective volume will replace the existing mechanically determined volume in establishing and maintaining the primary standard of the low-energy X-ray.

• Journal of Microbiology and Biotechnology
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• v.22 no.4
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• pp.535-540
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• 2012

${\beta}$-D-Xylosidase (E.C. 3.2.1.37) from Bifidobacterium breve K-110, which hydrolyzes ginsenoside Ra1 to ginsenoside Rb2, was cloned and expressed in Escherichia coli. The ($His_6$)-tagged recombinant enzyme, designated as XlyBK-110, was efficiently purified using $Ni^{2+}$-affinity chromatography (109.9-fold, 84% yield). The molecular mass of XylBK-100 was found to be 55.7 kDa by SDS-PAGE. Its sequence revealed a 1,347 bp open reading frame (ORF) encoding a protein containing 448 amino acids, which showed 82% identity (DNA) to the previously reported glycosyl hydrolase family 30 of Bifidobacterium adolescentis ATCC 15703. The $K_m$ and $V_{max}$ values toward p-nitrophenyl-${\beta}$-D-xylopyranoside (pNPX) were 1.45mM and 10.75 ${\mu}mol/min/mg$, respectively. This enzyme had pH and temperature optima at 6.0 and $45^{\circ}C$, respectively. XylBK-110 acted to the greatest extent on xyloglucosyl kakkalide, followed by pNPX and ginsenoside Ra1, but did not act on p-nitrophenyl-${\alpha}$-L-arabinofuranoside, p-nitrophenyl-${\beta}$-D-glucopyranoside, or p-nitrophenyl-${\beta}$-D-fucopyranoside. In conclusion, this is the first report on the cloning and expression of ${\beta}$-D-xylosidase-hydrolyzing ginsenoside Ra1 and kakkalide from human intestinal microflora.

• Food Science of Animal Resources
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• v.33 no.5
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• pp.565-571
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• 2013

An enzyme ${\beta}$-galactosidase or ${\beta}$-galactohydrolase [EC3.2.1.23], commonly called lactase, mediates galacto-oligosaccharide (GOS) synthesis under conditions of high substrate concentrations. Also, lactase hydrolyzes ${\beta}$($1{\rightarrow}4$) lactose into glucose and galactose, the latter is successively transferred to free lactose to make various oligosaccharides via transgalactosylation. GOS is non-digestible to human digestive enzymes and has been used as a functional prebiotics. Among the 24 lactic acid bacteria (LAB) strains used, Lactobacillus paracasei YSM0308 was selected based on its exhibition of the highest ${\beta}$-galactoside hydrolysis activity, and the crude lactase was prepared for examination of reaction conditions to affect the GOS synthesis. Lactase activity was measured with a spectrophotometer using ONPG (o-nitropheyl ${\beta}$-D-galactopyranoside) method. Lactase activity was not detected in the culture supernatant and was mostly present in the cell pellet after centrifugation. Activity of the crude lactase preparation ranges from102 to 1,053 units/mL, with the highest activity determined for L. paracasei YSM0308. Optimal conditions for GOS synthesis are as follows: concentration of whey powder, pH, temperature, and time were 30%, pH 6.5-7.0, $30^{\circ}C$, and 4 h, respectively. The final GOS concentration was 19.41% (w/v) by the crude YSM0308 lactase, which was obtained from strain YSM0308 grown in the 10% (w/v) reconstituted whey-based medium.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.432-438
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• 2015

This study examined the antimicrobial, antioxidant, and tyrosinase inhibitory activities of bioactive compounds extracted from two starfish, Asterina pectinifera and Asterias amurensis, using solvent extraction after $Protamex^{TM}$ hydrolysis. Methanol and acetone fractions collected by stepwise extraction from specimens were subjected to silica gel column chromatography (SGCC) (200 mesh and 400 mesh), followed by high-performance liquid chromatography (HPLC). Two fractions (7:3 and 5:5 chloroform : methanol ratio, v/v) eluted using silica gel column chromatography from the two starfishes showed higher antimicrobial activity against Propionibacterium acnes and dermatophyte fungi (Epidermophyton floccosum, Microsporum audouinii, Trichophyton ferrugineum, Trichophyton mentagrophytes, and Trichophyton rubrum), antioxidant activity ($EDA_{50}$, mg/mL), and tyrosinase inhibitory activity compared to the other fractions. The final fractions obtained from Asterina pectinifera (RT 7.53, 8.93, and 10.48 min) and Asterias amurensis (RT 5.02 min) by SGCC (400 mesh) and HPLC from two SGCC fractions (200 mesh) showed 8.94 and 15.59 mg/mL antioxidant activity ($EDA_{50}$) and 46.89 and 40.19 % tyrosinase inhibitory activity, respectively. Extracts from starfishes are potential cosmetic basic material.

• The Journal of Advanced Prosthodontics
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• v.10 no.3
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• pp.252-258
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• 2018

PURPOSE. The purpose of this study was to evaluate the repeatability and matching accuracy between two identical intraoral spectrophotometers. MATERIALS AND METHODS. The maxillary right central incisor, canine, and mandibular left central incisor of each of 30 patients were measured using 2 identical intraoral spectrophotometers with different serial numbers (EasyShade V). The color of each shade tab from 3 shade guides (VITA 3D-Master) was also determined with both devices. All measurements were performed by a single operator. Statistical analyses were performed to verify the repeatability, accuracy, and the differences between the devices with paired t-tests, one-way ANOVA, and intra-class correlation coefficients (ICCs) (${\alpha}=.05$). RESULTS. A high level of measurement repeatability (ICC>0.90) among $L^*$, $a^*$, and $b^*$ color components was observed within and between devices (P<.001). Intra-device matching agreement rates were 80.00% and 81.11%, respectively, while inter-device matching agreement rate was 51.85%. ANOVA revealed no significant different color values within each device, while paired t-test provided significant different color values between both devices. The CIEDE2000 color differences between both devices were $2.28{\pm}1.61$ ${\Delta}E_{00}$ for in-vivo readings. Regarding the clinical matching accuracy of both devices, ${\Delta}E_{00}$ values between teeth and matching shade tabs were $3.05{\pm}1.19$ and $2.86{\pm}1.02$, respectively. CONCLUSION. Although two EasyShade V devices with different serial numbers show high repeatability of CIE $L^*$, $a^*$, and $b^*$ measurements, they could provide different color values and shade for the same tooth.

• Journal of the Korean Institute of Gas
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• v.12 no.1
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• pp.13-18
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• 2008

Vibration velocity induced by earthquakes or external vibration sources is one of the integrity assessment indexes, and is also a representative value used to describe the amount of vibration because it is based on a proportional relationship with the damage scale. In this study, the vibration velocity criterion for structures is first examined. Then, based on the velocity criterion, an integrity assessment is performed. Burial condition is set up based on the "Highway and Local Road Design Criteria" with API 5L Gr. X65 pipeline(D=762 mm). The FE model considers DB-24 vehicle load as a time function with a varying velocity in the range of $20{\sim}160\;km/h$. Maximum vibration velocity occurs at v=80 km/h and decreases after v=80 km/h. The maximum vibration velocity of buried pipeline by DB-24 loads is about 0.034 cm/s. The velocity that occurs is in the range of allowable values for each vibration velocity criterion. The wave propagation velocity was identified based on attenuation law and the minimum value appears at vehicle velocity 80 km/h that has maximum vibration velocity.

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.818-825
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• 2012

Keratinases are exciting keratin-degrading enzymes; however, there have been relatively few studies on their immobilization. A keratinolytic protease from Chryseobacterium sp. kr6 was purified and its partial sequence determined using mass spectrometry. No significant homology to other microbial peptides in the NCBI database was observed. Certain parameters for immobilization of the purified keratinase on chitosan beads were investigated. The production of the chitosan beads was optimized using factorial design and surface response techniques. The optimum chitosan bead production for protease immobilization was a 20 g/l chitosan solution in acetic acid [1.5% (v/v)], glutaraldehyde ranging from 34 g to 56 g/l, and an activation time between 6 and 10 h. Under these conditions, above 80% of the enzyme was immobilized on the support. The behavior of the keratinase loading on the chitosan beads surface was well described using the Langmuir model. The maximum capacity of the support ($q_m$) and dissociation constant ($K_d$) were estimated as 58.8 U/g and 0.245 U/ml, respectively. The thermal stability of the immobilized enzyme was also improved around 2-fold, when compared with that of the free enzyme, after 30 min at $65^{\circ}C$. In addition, the activity of the immobilized enzyme remained at 63.4% after it was reused five times. Thus, the immobilized enzyme exhibited an improved thermal stability and remained active after several uses.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1550-1551
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• 2006

An L-band linear accelerator system for e-beam sterilization is under design for bio-technology application. The klystron-modulator system as RF microwave source has an important role as major components to offer the system reliability for long time steady state operation. A PFN line type pulse generator with a peak power of 71.5-MW, $7{\mu}s$, 285 pps is required to drive a high-power klystron. The high power pulse transformer has a function of transferring pulse energy from a pulsed power source to a high power load. The pulse transformer producing a pulse with a peak voltage of 275 kV is required to produce 30-MW peak and 60 kW average RF output power at the frequency of 1.3-GHz. We have designed the high power pulse transformer with 1:13 step-up ratio. The peak and average power capability is 71.5-MW (275 kV, 260 A at load side with $7{\mu}s$ pulse width) and 130 kW, respectively. In this paper, we present a system overview and initial design results of the high power pulse transformer.