• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.542-549
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• 1995

This study was conducted to obtain accurate data on intake, excretion, apparent digestibility and balance of zinc which Korean take in habitually. This study applied to the seven high school girls from 15 to 16 years old. Their food intake, feces and urine were collected and intake and excretion of zinc in them were measured by atomic absorption spectrophotometry. The measurement continued for four weeks while they maintained their normal living pattern and body weight. Each girl's daily intake and excretion of zinc were measured and apparent digestibility and balance were also studied. Each girl's daily mean intake, fecal excretion and apparent digestibility of zinc were $9.26{\pm}2.30mg,\;3.31{\pm}2.15mg,\;and\;62.92{\pm}3.22%$, respectively. The urinary excretion of zinc was $3.23{\pm}1.03mg$ and showed the positive balance of $2.61{\pm}2.91mg$.

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1428-1438
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• 2016

In the present work, Arthrobacter sp. 25, a lead-tolerant bacterium, was assayed to remove lead(II) from aqueous solution. The biosorption process was optimized by response surface methodology (RSM) based on the Box-Behnken design. The relationships between dependent and independent variables were quantitatively determined by second-order polynomial equation and 3D response surface plots. The biosorption mechanism was explored by characterization of the biosorbent before and after biosorption using atomic force microscopy (AFM), scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results showed that the maximum adsorption capacity of 9.6 mg/g was obtained at the initial lead ion concentration of 108.79 mg/l, pH value of 5.75, and biosorbent dosage of 9.9 g/l (fresh weight), which was close to the theoretically expected value of 9.88 mg/g. Arthrobacter sp. 25 is an ellipsoidal-shaped bacterium covered with extracellular polymeric substances. The biosorption mechanism involved physical adsorption and microprecipitation as well as ion exchange, and functional groups such as phosphoryl, hydroxyl, amino, amide, carbonyl, and phosphate groups played vital roles in adsorption. The results indicate that Arthrobacter sp. 25 may be potentially used as a biosorbent for low-concentration lead(II) removal from wastewater.

• Macromolecular Research
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• v.11 no.1
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• pp.25-35
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• 2003

A series of random poly(ethylene-co-1,4-butylene terephthalate)s (PEBTs), as well as poly(ethylene terephthalate) (PET) and poly(1,4-butylene terephthalate) (PBT), were synthesized by the bulk polycondensation. Their composition, molecular weight, and thermal properties were determined. All the copolymers are crystallizable, regardless of the compositions, which may originate from both even-atomic-numbered ethylene terephthalate and butylenes terephthalate units that undergo inherently crystallization. Non-isothermal crystallization exotherms were measured over the cooling rate of 2.5-20.0 K/min by calorimetry and then analyzed reasonably by the modified Avrami method rather than the Ozawa method. The results suggest that the primary crystallizations in the copolymers and the homopolymers follow a heterogeneous nucleation and spherulitic growth mechanism. However, when the cooling rate increases and the content of comonomer unit (ethylene glycol or 1,4-butylene glycol) increases, the crystallization behavior still becomes deviated slightly from the prediction of the modified Avrami analysis, which is due to the involvement of secondary crystallization and the formation of relatively low crystallinity. Overall, the crystallization rate is accelerated by increasing cooling rate but still depended on the composition. In addition, the activation energy in the non-isothermal crystallization was estimated.

• Toxicological Research
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• v.28 no.4
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• pp.263-268
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• 2012

The aim of this study was to investigate the acute oral toxicity of fermented Scutellariae Radix (JKTMHGu-100) in rats and dogs. JKTM-HGu-100 was orally administered at a dose of 2,000 mg/kg in Sprague-Dawley rats. An escalating single-dose oral toxicity test in beagle dogs was performed at doses of 500, 1000, and 2000 mg/kg with 4-day intervals. Clinical signs, changes in body weight, mortality, and necropsy findings were examined for 2 weeks following oral administration. No toxicological changes related to the test substance nor mortality was observed after administration of a single oral dose of JKTM-HGu-100 in rats or dogs. Therefore, the approximate lethal dose (LD) for oral administration of JKTMHGu-100 in rats was considered to be over 2,000 mg/kg, and the maximum tolerance doses (MTDs) in rats and dogs were also estimated to be over 2,000 mg/kg. These results indicate that JKTM-HGu-100 shows no toxicity in rodents or non-rodents at doses of 2,000 mg/kg or less.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.209-213
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• 2010

Bacterial blight is one of the most serious diseases of rice (Oryza sativa L.), and it has been known that Xanthomonas oryzae pv. oryzae (Xoo) causes this disease symptom. To develop resistance rice cultivars against Xoo, 3,000 lines of $M_3$ mutants, which were irradiated with gamma ray, were tested by 'scissor-dip method' primarily, and 191 putative resistant lines were selected. In $M_4$ generation, these lines were screened again with various ways such as measuring of symptom of bacterial blight in leaf, number of tiller, fresh weight, and phenotypic segregation ratio in next generation. Finally, six resistance lines were selected. RT-PCR analysis revealed that these lines displayed high level of R-genes such as Xa21, Pi36, and Pi-ta. These results indicate that mutations by gamma ray cause disruptions of regulatory signal transduction systems of these R-genes. Furthermore, these selected mutants could be useful for the development of rice cultivar resistant to Xoo.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2253-2261
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• 2022

In this study, nano-scaled shielding materials were assembled and fabricated by doping different weight percentages of Nano-mercuric oxide (N-HgO) into Nano-Bentonite (N-Bent) based on using (100-x% N-Bent + x% N-HgO, x = 10, 20, 30, and 40 wt %). The fabricated N-HgO/N-Bent nanocomposites were characterized by FT-IR, XRD, and SEM and evaluated to evaluate their shielding properties toward gamma radiation by using four different γ-ray energies form three point sources; 356 keV from ¹³³Ba, 662 keV from ¹³⁷Cs as well as 1173, and 1332 keV from ⁶⁰Co. The γ-rays mass attenuation coefficients were plotted as a function of the doped N-HgO concentrations into N-HgO/N-Bent nanocomposites. The computed values of mass attenuation coefficients (µ_m), effective atomic number (Z_eff) and electron density (N_el) by the as-prepared samples were found to increase, while the half value layer (HVL) and mean free path (MFP) were identified to decrease upon increasing the N-HgO contents. It was concluded also that the increase in N-HgO concentration led to a direct increase in the mass attenuation coefficient from 0.10 to 0.17 cm²/g at 356 keV and from 0.08 to 0.09 cm²/g at 662 keV. However, a slight increase was observed in the identified mass attenuation coefficients at (1172 and 1332 keV).

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.220-225
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• 2022

Perlite is one of the major constituents of the radioactive thermal insulation waste (RTIW) originating from nuclear power plants and, for proper waste management, a significant reduction in its volume is required prior to disposal. In this work, the volume reduction of perlite is studied by high-temperature treatment method with using K₂CO₃ as a flux. The perlite is ground with 0-30 wt% K₂CO₃, and differential thermal analysis/thermogravimetric analysis is used to monitor the glass transition temperature (T_g) and weight loss. The Tg varied between ~772.2 and 837.1 ℃ with the minima at ~643.5 ℃ with the addition of ~10 wt% K₂CO₃. It is observed that compared to the pure perlite the volume reduction ratio (VRR) increases with the addition of K₂CO₃. The VRR of 11.20 is observed with 5 wt% K₂CO₃ at 700 ℃, as compared to VRR of 5.56 without K₂CO₃ at 700 ℃. The X-ray photoelectron spectroscopy and scanning electron microscopy are used to characterize perlite samples heat-treated without/with 5 wt% K₂CO₃ at 700 ℃. Moreover, the atomic absorption spectroscopy indicates that the proposed heat-treatment procedure is able to completely retain the radionuclides present in the perlite RTIW.

• Journal of Radiation Protection and Research
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• v.47 no.4
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• pp.214-225
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• 2022

Background: The conventional cerium-doped Gd₂Al₂Ga₃O₁₂ (GAGG(Ce)) scintillator-based gamma-ray imager has a bulky detector, which can lead to incorrect positioning of the gammaray source if the shielding against background radiation is not appropriately designed. In addition, portability is important in complex environments such as inside nuclear power plants, yet existing gamma-ray imager based on a tungsten mask tends to be weighty and therefore difficult to handle. Motivated by the need to develop a system that is not sensitive to background radiation and is portable, we changed the material of the scintillator and the coded aperture. Materials and Methods: The existing GAGG(Ce) was replaced with Bi₄Ge₃O₁₂ (BGO), a scintillator with high gamma-ray detection efficiency but low energy resolution, and replaced the tungsten (W) used in the existing coded aperture with lead (Pb). Each BGO scintillator is pixelated with 144 elements (12 × 12), and each pixel has an area of 4 mm × 4 mm and the scintillator thickness ranges from 5 to 20 mm (5, 10, and 20 mm). A coded aperture consisting of Pb with a thickness of 20 mm was applied to the BGO scintillators of all thicknesses. Results and Discussion: Spectroscopic characterization, imaging performance, and image quality evaluation revealed the 10 mm-thick BGO scintillators enabled the portable gamma-ray imager to deliver optimal performance. Although its performance is slightly inferior to that of existing GAGG(Ce)-based gamma-ray imager, the results confirmed that the manufacturing cost and the system's overall weight can be reduced. Conclusion: Despite the spectral characteristics, imaging system performance, and image quality is slightly lower than that of GAGG(Ce), the results show that BGO scintillators are preferable for gamma-ray imaging systems in terms of cost and ease of deployment, and the proposed design is well worth applying to systems intended for use in areas that do not require high precision.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.701-710
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• 2004

Uncertainty was quantified to evaluate calcium determination result in infant formula with AAS (Atomic Absorption Spectrometry) and ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Uncertainty sources in measurand, such as sample weight, final volume of sample, sample dilution and the instrumental result were identified and used as parameters for combined standard uncertainty based on the GUM (Guide to the expression of uncertainty in measurement) and Draft EURACHEM/CITAC Guide. Uncertainty components of each sources in measurand were identified as resolution, reproducibility and stability of chemical balance, standard material purity, standard material molecular weight, standard solution concentration, standard solution dilution factor, sample dilution factor, calibration curve, recovery, instrumental precision, reproducibility, and stability, Each uncertainty components were evaluated by uncertainty types and included to calculate combined uncertainty. The kinds of uncertainty sources and components in the analytical method by AAS and ICP-AES were same except sample dilution factor for AAS. The analytical results and combined standard uncertainties of calcium content were estimated within the certification range $(367{\pm}20\;mg/100g)$ of CRM (Certified Reference Material) and were not significantly different between method by AAS followed by ashing and method by ICP-AES followed by acid digestion as $359.52{\pm}23.61\;mg/100g\;and\;354.75{\pm}16.16\;mg/100g$, respectively. Identifying uncertainty sources related with precision, repeatability, stability, and maintaining proper instrumental conditions as well as personal proficiency was needed to reduce analytical error.

• Journal of Life Science
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• v.26 no.10
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• pp.1121-1129
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• 2016

High-molecular-weight glutenin subunits (HMW-GSs) are extremely important determinants of the functional properties of wheat dough. Transgenic rice plants containing a wheat TaGlu-Ax1 gene encoding a HMG-GS were produced from the Korean wheat cultivar ‘Jokyeong’ and used to enhance the bread-making quality of rice dough using the Agrobacterium-mediated co-transformation method. Two expression cassettes with separate DNA fragments containing only TaGlu-Ax1 and hygromycin phosphotransferase II (HPTII) resistance genes were introduced separately into the Agrobacterium tumefaciens EHA105 strain for co-infection. Rice calli were infected with each EHA105 strain harboring TaGlu-Ax1 or HPTII at a 3:1 ratio of TaGlu-Ax1 and HPTII. Among 210 hygromycin-resistant T₀ plants, 20 transgenic lines harboring both the TaGlu-Ax1 and HPTII genes in the rice genome were obtained. The integration of the TaGlu-Ax1 gene into the rice genome was reconfirmed by Southern blot analysis. The transcripts and proteins of the wheat TaGlu-Ax1 were stably expressed in rice T₁ seeds. Finally, the marker-free plants harboring only the TaGlu-Ax1 gene were successfully screened in the T₁ generation. There were no morphological differences between the wild-type and marker-free transgenic plants. The quality of only one HMW-GS (TaGlu-Ax1) was unsuitable for bread making using transgenic rice dough. Greater numbers and combinations of HMW and LMW-GSs and gliadins of wheat are required to further improve the processing qualities of rice dough. TaGlu-Ax1 marker-free transgenic plants could provide good materials to make transgenic rice with improved bread-making qualities.