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  • Author or Editor: Jin Kim x
  • Chemistry and Chemical Engineering x
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Abstract  

The organometallic precursor of fac-[99mTc(CO)3(H2O)3]+ has attracted much attention because of the robustness and small size of Tc(I)-tricarbonyl complexes compared to Tc(V) complexes and the good labeling affinity with a variety of donor atoms. Among various ligand systems, an iminodiacetic acid (IDA) was proven as a good chelating group to form a Tc(III)-compelx as well as has been shown its potential as a chelating system for fac-[99mTc(CO)3] precursor. In an attempt to confirm the similarity and the difference between 99mTc(CO)3-IDA and 99mTc-(IDA)2-complex, M(CO)3-IDA (M = 99mTc, Re) complexes of disofenin, mebrofenin and N-(3-iodo-2,4,6-trimethyl phenylcarbamoylmethyl) iminodiacetic acid were prepared, and the biological evaluation of 99mTc(CO)3-disofenin was performed. The 99mTc(CO)3-IDA complexes were prepared with a high radiolabeling yield (>98%) in a quantitative manner and showed a negative charge. The in vivo pharmacokinetic behavior of 99mTc(CO)3-disofenin showed a similar biological activity to 99mTc-(disofenin)2 in that those complexes were quickly cleared from the blood by the hepatocytes and excreted into the gallbladder and intestine. Accordingly, the 99mTc(CO)3-IDA derivatives of disofenin and mebrofenin might be used as hepatobiliary imaging agents. Since an IDA is a promising chelator for 99mTc-based radiopharmaceutical and the biological properties of 99mTc(CO)3-IDA derivative shows similar to that of 99mTc-complex, a biomolecule containing IDA can be freely radiolabeled with fac-[99mTc(CO)3]-precursor or 99mTc. However, the radiolabeling efficiency and the biological behavior demonstrates the favorable properties of 99mTc(CO)3-IDA compound for the development of a new imaging agent.

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Summary  

Instrumental neutron activation analysis was conducted on PM 10 samples collected in Daejeon city, Korea during September 2001 to May 2002. Our measurement data were analyzed to explain the behavior of particle-bound elemental components in relationship with Asian Dust (AD) events. The results of our analysis indicated that the major crustal elements (e.g., Al, Ca, Fe, K, Mg, and Ti) showed strong enrichment (about 3 to 9 times higher concentration levels) during the AD period accompanied by the increase in the PM 10 levels (e.g., by about 3 times). However, the concentrations of anthropogenically derived elements (such as As, Br, Sb, Se and Zn) exhibited moderate change during the AD period. Hence, the computation of enrichment factor (EF) indicated that the magnitude of EF values during the AD period was even smaller in the case of toxic metals than its non-AD counterpart. The existence of relatively low EF values during the AD period can be attributed to the excessive input of crustal components. The overall results of our study suggest that both absolute and relative elemental composition of aerosol particles can be altered significantly by the AD events.

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Summary  

A prompt gamma activation analysis facility has been constructed on the ST1 horizontal beam port at the HANARO research reactor, KAERI in 2003. The detector system consists of a high-purity Ge detector surrounded by BGO/NaI(Tl) scintillators as an annulus type to reject the Compton scattered photons. Detection sensitivity for boron was obtained from the prompt gamma-ray spectra of boric acid, B(OH)3, containing 0.1-65 μg boron. The net peak for the calculation of the boron concentration was obtained by eliminating the sodium 472 keV peak, involved in the boron 478 keV peak. The biological samples used are NIST SRMs such as Peach Leaves, Apple Leaves, Tomato Leaves, Spinach Leaves, Total Diet, Typical Diet, Oyster Tissue and Corn Bran, etc. The measured values for high boron concentration showed up to a 3% of the relative, but in a low concentration below 5 ppm, present values were higher than the certified ones.

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Summary  

For the identification of air pollution sources, about 500 airborne particulate matter (PM2.5and PM10) samples were collected by using a Gent air sampler and a polycarbonate filter in an urban region in the middle of Korea from 2000 to 2003. The concentrations of 25 elements in the samples were measured by using instrumental neutron activation analysis (INAA). Receptor modeling was performed on the air monitoring data by using the positive matrix factorization (PMF2) method. According to this analysis, the existence of 6 to 10PMF factors, such as metal-alloy, oil combustion, diesel exhaust, coal combustion, gasoline exhaust, incinerator, Cu-smelter, biomass burning, sea-salt, and soil dust were identified.

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Summary  

As part of an air pollution monitoring study, airborne particulate matter (PM2/PM10-2) samples were collected from 2000 to 2003 at two sampling sites in an urban region, Daejeon, the middle of Korea. Mass concentrations of both fine and coarse fractions and that of the black carbon in the fine particles were measured using the Gent stacked filter unit sampler and the smoke stain reflectometer, respectively. In the collected samples the concentrations of 24 elements were analyzed using instrumental neutron activation analysis. Monitored data were investigated for their temporal trends under different environmental conditions and their seasonal correlation patterns. Crustal enrichment factors were also estimated to establish the contribution between anthropogenic and crustal origin. Patterns for airborne particle matter (APM) and elemental concentrations, seasonal variation of some marker elements were investigated. The results can be applied for the investigation of further air pollution sources and for the evaluation of air quality.

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Deoxypodophyllotoxin (DPT), or anthricin, is a lignan isolated from the roots of Anthriscus sylvestris and is reported to exhibit anti-inflammatory, anti-oxidant, and anti-asthmatic effects. Herein, the conditions for the extraction of DPT from A. sylvestris are optimized using a Box–Behnken design (BBD) method based on response surface methodology (RSM). DPT was detected by ultra-performance liquid chromatography coupled with photodiode array and quadrupole detector (UPLC–PDA–QDa) and analytical validation methods based on International Conference on Harmonization (ICH) guidelines. In preliminary experiments, the experimental conditions of extraction time, solvent percentage, and temperature were selected for optimization. The adequacy of the experimental model was statistically evaluated, and the regression coefficient (R 2), adjusted regression coefficient (R 2 adjust), and p-value of the lack-of-fit were determined as 97.86%, 94.02%, and 0.124, respectively. The maximum yield of DPT was estimated to be 2.341 mg/g for 30 min in 100% methanol at 60 °C, and the actual yield was measured as 2.295 mg/g (±0.023) under the same conditions.

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Abstract  

High surface area, ordered nanoporous carbon (CMK-3) and its chelating polymer composites were successfully prepared and utilized for the removal of U(VI) from aqueous solutions. Carboxymethylated polyethyleneimine (CMPEI) with a strong chelating property was introduced to the pore surface and inner pores of CMK-3 substrate. CMPEI-modified CMK-3 composite (CMPEI/CMK-3) was characterized by scanning electron microscopy and nitrogen sorption. U(VI) sorption capacity was significantly improved by the surface modification of CMK-3 by CMPEI. The CMPEI/CMK-3 showed enormously increased sorption capacities, compared with those of previous sorbents (e.g., surface-functionalized silicas). In particular, the CMPEI/CMK-3 showed a significantly high uranium retention property while allowing only about 1% U(VI) to leach out over a 4 month time period, when treated with polyacrylic acid.

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Abstract  

The k 0-standardization method (k 0-NAA) is known as one of the most remarkable progresses of the NAA with its many advantages. For the application of k 0-NAA method at the NAA #1 irradiation position where the neutrons are well thermalized in the HANARO research reactor, KAERI, Korea, the determination of the reactor neutron spectrum parameters such as α and f have been carried out. The measured values of α and f using the “Cd-ratio” triple monitor method were 0.127±0.022 and 1010±70, respectively. To evaluate the applicability of k 0-NAA in our analytical system, the analysis of three kinds of SRMs was executed. The analytical results showed that the relative error of most of the elements was less than 10% and the U-scores were within 2. It is turned out that the procedure of the k 0-NAA in the HANARO research reactor is available for a practical application in the environmental fields.

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Abstract  

To enhance the applicability of the nuclear analytical technique in the field of industry and the environment, the inorganic elemental content of the bottom ash from a municipal solid waste incinerator was determined by instrumental neutron activation analysis. Bottom ash samples were monthly collected from an incinerator located at a metropolitan city in Korea, strained through a 5 mm sieve, dried by an oven and pulverized by an agate mortar. The samples were irradiated at the NAA #1 irradiation hole (thermal neutron flux: 2.92·1013 n·cm−2·s−1) in the HANARO research reactor of the Korea Atomic Energy Research Institute and the irradiated samples were measured by a HP Ge gamma-ray spectrometer. Thirty-three elements including As, Cr, Cu, Fe, Mn, Sb and Zn were analyzed by an absolute method. The quality control was conducted by a simultaneous analysis with NIST standard reference materials. The average concentrations of the major elements such as Ca, Fe, Al, Na, Mg, K and Ti measured in the sample were 19.9%, 4.85%, 3.79%, 2.11%, 1.84%, 1.22% and 1.02%, respectively. In addition, the concentrations of the hazardous metals like Zn, Cu, Cr, Sb and As were 0.77%, 0.31%, 729 mg·kg−1, 116 mg·kg−1 and 22.2 mg·kg−1, respectively.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Yong-Sam Chung, Sun-Ha Kim, Jong-Hwa Moon, Sung-Yeol Baek, Young-Jin Kim, Hark-Rho Kim, Il-Jin Park and Kyung-Sik Min

Abstract  

A fast pneumatic transfer system for an instrumental neutron activation analysis and delayed neutron counting system were reconstructed with new designs of a functional improvement at the HANARO research reactor in 2006. The design, conception, operation and control of these systems are described. Also the experimental characteristic parameters by a functional operation test and an irradiation test of these systems, such as the transfer time, the neutron flux, the temperature of the irradiation position with an irradiation time, the radiation dose rate when the rabbit is returned, etc., are reported to provide a user information as well as for the management and safety of the reactor.

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