• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.73-74
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• 2016

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2358-2368
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• 2011

Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations, employing the B3LYP method and the LANL2DZ, 6-31G$^*$(LANL2DZ for Tc), 6-31G$^*$(cc-pVDZ-pp for Tc) and DGDZVP basis sets, have been performed to investigate the electronic structures and absorption spectra of the technetium-99m-labeled methylenediphosphonate ($^{99m}Tc$-MDP) complex of the simplest diphosphonate ligand. The bonding situations and natural bond orbital compositions were studied by the Mulliken population analysis (MPA) and natural bond orbital (NBO) analysis. The results indicate that the ${\sigma}$ and ${\pi}$ contributions to the Tc-O bonds are strongly polarized towards the oxygen atoms and the ionic contribution to the Tc-O bonding is larger than the covalent contribution. The electronic transitions investigated by TDDFT calculations and molecular orbital analyses show that the origin of all absorption bands is ascribed to the ligand-to-metal charge transfer (LMCT) character. The solvent effect on the electronic structures and absorption spectra has also been studied by performing DFT and TDDFT calculations at the B3LYP/6-31G$^*$(cc-pVDZ-pp for Tc) level with the integral equation formalism polarized continuum model (IEFPCM) in different media. It is found that the absorption spectra display blue shift in different extents with the increase of solvent polarity.

• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.243-250
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• 2006

Three novel potential metal ion chelating units have been synthesized and characterized: 5-hexylcarbamoyl-3,4-dihydroxythiophene-2-carboxylic acid methyl ester (5), 3-benzyloxy-4-hydroxythiophene-2,5-dicarboxylic acid bis-hexylamide (6), and 3,4-dihydroxythiophene-2,5-dicarboxylic acid bis-hexylamide (7). The crystal structure of 6 was obtained and suggests the presence of three distinct intramolecular hydrogen bonds, namely $[N_{amide}-H{\cdot}{\cdot}{\cdot}O]$ $[O-H{\cdot}{\cdot}{\cdot}O_{amide}]$ and $[N_{amide}-H{\cdot}{\cdot}{\cdot}S]$. Boron chelation with 5, 6 and 7 through the use of $BF_3, \;B(OH)_3 \;or \;B(OMe)_3$ was probed by $^1H$, $^{11}B$, and $^{13}C$ NMR spectroscopy. Technetium (I) chelation with 5, 6 and 7 was also studied via HPLC elutions using $[^{99m}Tc(CO)_3(OH_2)_3]^+$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.1
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• pp.13-19
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• 2012

The long-lived fission products $^{79}Se$ and $^{99}Tc$ have been considered as the major concern nuclides for the disposal of radioactive waste because of their high solubilities and the existence of anionic species in natural water. In this study, the solubilities of $FeSe_2(s)$ and $TcO_2(s)$, known as respective Solubility Limiting Solid Phase (SLSP) of selenium and technetium, were measured in the KURT (KAERI Underground Research Tunnel) groundwater under various pH and redox conditions. And their solubilities and major species were also calculated using geochemical codes under conditions similar to experimental solutions. Experimental results and calculation for $FeSe_2$ show that the solubility of selenium was found to be below $1{\times}10^{-6}mol/L$ under the condition of pH 8~9.5 and Eh=-0.3~-0.4 V while the dominant species was identified as $HSe^-$. For $TcO_2$, the solubility of technetium was found to be $5{\times}10^{-8}{\sim}1{\times}10^{-9}mol/L$ in the solutions of pH 6~9.5 and Eh<-0.1 V, while the dominant species was $TcO(OH)_2$. However, when the Eh of the solution is -0.35 V, $TcO(OH)_3^-$ and $TcO_4^-$ are calculated as the dominant species at pH 10.5~12 and pH>12, respectively.

• 대한핵의학회:학술대회논문집
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• 1990.04a
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• pp.214-214
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• 1990

• 대한핵의학회:학술대회논문집
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• 1990.04a
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• pp.209.2-210
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• 1990

• 대한핵의학회:학술대회논문집
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• 2003.11a
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• pp.15.2-15.2
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• 2003

• The Korean Journal of Nuclear Medicine
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• v.2 no.1
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• pp.59-66
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• 1968

Technetium 99m pertechnetate brain scanning were performed in 3 cases of head injury (2 chronic subdural hematomas and 1 acute epidural hematoma), 2 cases of brain abscess and I case of intracerebral hematoma associated with arteriovenous anomaly. In all the cases brain scintigrams showed "hot areas." Literatures on radioisotope scanning of intracranial lesions were briefly reviewed. With the improvement of radioisotope scanner and development of new radiopharmaceuticals brain scanning became a safe and useful screening test for diagnosis of intracranial lesions. Brain scanning can be easily performed even to a moribund patient without any discomfort and risk to the patient which are associated with cerebral angiography or pneumoencephalography. Brain scanning has been useful in diagnosis of brain tumor, brain abscess, subdural hematoma, and cerebral vascular diseases. In 80 to 90% of brain tumors positive scintigrams can be expected. Early studies were done with $^{203}Hg$-Neohydrin or $^{131}I$-serum albumin. With these agents, however, patients receive rather much radiation to the whole body and kidneys. In 1965 Harper introduced $^{99m}Tc$ to reduce radiation dose to the patient and improve statistical variation in isotope scanning.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1449-1455
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• 2022

A radiotracer investigation was carried out in a Thermal Stratification Test Facility (TSTF) with objectives of investigating the dispersion and diffusion of radionuclide and effectiveness of the thermocline to minimize the radionuclide content in the hot water layer. Technetium-99m (^99mTc) as sodium pertechnetate was used as a radiotracer in the investigation. Qualitative analysis showed that a thermocline is formed within the TSTF and is effective in preventing the transport of radionuclide from bottom section to the top section of the facility. It was found that the radiotracer injected at the bottom of the pool took about 17.4 h to disperse from bottom to the top of the facility. The results of the investigation helped in understanding the effectiveness of hot water layer and thus to minimize the pool top radiation levels.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.559-565
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• 1997

Donor airway ischemia is a significant problem after tracheal replacement with homograft or lung transplantation, Several factors such as omentopexy, heparin, PGl2 and fibroblast growth factor, have been shown to induce angiogenesis in vitro and in vivo. This study was designed to investigate whether omentopexy and basic flbroblast growth factor can enhance rabbit tracheal revascularization and epithelial regeneration, Three different experiments were performed with New Zealand white rabbit. In group I(n= 15 control group), only coNical tracheal autotransplantation was done. In group II(n= 15), cervical tracheal autotransplantation with omentopexy was done through subcutaneous route. In group III(n= 15), cervical tracheal autotransplantation was done and lug basic flbroblast growth factor was applied. After 3, 7 and 14 days, the animals were sacrificed. The extent of revascularization was investigated by means of uptake of the human serum albumin labelled with 99m technetium, and epithelial regeneration were assessed by means of light microscope. In the group investigated at day 3, there was statistically significant high tracheal revascularization in group III(p<0.05), but no difference at 7 and 14 days. And epithelial regenerations at day 3 were better in group III(p<0.05), and at day 7 in group II and III. But there was no difference at day 14. We concluded that b-FGF can enhance the revascularization and epithelial regeneration of the tracheal autograft especially in early phase.