• Journal of Radiation Industry
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• v.10 no.4
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• pp.181-187
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• 2016

Selective ${\beta}_1$-agonist and antagonists are used for the treatment of cardiac diseases including congestive heart failure, angina pectoris and arrhythmia. Selective ${\beta}_1$-antagonists including nebivolol have high binding affinity on ${\beta}_1$-adrenergic receptor, not ${\beta}_2$-receptor mainly expressed in smooth muscle. Nebivolol is one of most selective ${\beta}_1$-blockers in clinically used ${\beta}_1$-blockers including atenolol and bisoprolol. We tried to develop clinically useful cardiac PET tracers using a selective ${\beta}_1$-blocker. Nebivolol is $C_2$-symmetric and has two chromane moiety with a secondary amino alcohol and aromatic fluorine. We adopted the general synthetic strategy using epoxide ring opening reaction. Unlike formal synthesis of nebivolol, we prepared two chromane building blocks with fluorine and iodine which was transformed to diaryliodonium salt for labelling of $^{18}F$. Two epoxide building blocks were readily prepared from commercially available chromene carboxylic acids (1, 8). Then, the amino alcohol building block (15) was prepared by ammonolysis of epoxide (14) followed by coupling reaction with the other building block, epoxide (7). Diaryliodonium salt, a precursor for $^{18}F$-aromatic substitution, was synthesized in moderate yield which was readily subjected to $^{18}F$-aromatic substitution to give $^{18}F$-labelled nebivolol.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.3 no.2
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• pp.122-128
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• 2017

In the 2000s, there has been a significant advance on carbon-fluorine (C-F) bond formation reactions via transition metal mediated or catalyzed methods. Of course, for the past 10 years, transition metal catalysis improves C-F bond formation in terms of practicality and even can be applied to C-18F bond formation reaction. In this mini-review, we summarize various transition metal mediated or catalyzed fluorination reactions, which were developed in the mid-2000s.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.683-686
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• 2005

This paper is related to investigate adding effect of fluorine-silicate hybrid type crack controlling agent(FS) on initial behavior, dynamic properties, adibatic hydration temp, and plastic crack behavior of concrete(Specification : 25-30-18). It is appeared that adding of FS contributed to strength elevation, lowering of hydration temperature as well as plastic crack reduction without disturbance of initial behaviors of concrete such as slump, air content and setting.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.540-545
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• 2010

In this study, we have investigated new plasma resistant materials with less usage of rare-earth oxides than $Y_2O_3$ which is currently used in the semiconductor industry. We observed the stability ranges of $(Gd{\cdot}Y)_3Al_5O_{12}$ and $(La{\cdot}Y)Al_{11}O_{18}$ ternary systems, and measured their etch rates under typical fluorine plasma. $(Gd{\cdot}Y)_3Al_5O_{12}$ system showed an extensive solid solution up to 80 mol% gadolinium, but $(La{\cdot}Y)Al_{11}O_{18}$ showed a negligible substitution between rare-earth ions, which can be explained by the differences between the ionic radii. The etch rates depended on the total amount of rare-earth oxides but not on the substitution of the rare-earth ions. When the specimen was examined using XPS after the exposure to fluorine plasma, the strong surface fluorination was observed with a shift of the binding energy to higher energy.

• Journal of the Korean Chemical Society
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• v.13 no.1
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• pp.68-74
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• 1969

Flourination of Ethyl, ${\alpha},{\beta$}-dichloro-${\beta$}-phenyl propionate, Ethyl ${\alpha},{\beta$}-dibromo ${\beta$}-phenyl propionate, Ethyl ${\alpha},{\beta$}-dichloro ${\beta$}-(p-chloro-phenyl) propionate, and dibromostyrene by potassium fluoride were investigated in presence of dimethyl formamide, diethylene glycol, and diethylene glycol monomethyl-ether. The reactivity of these organic halogen esters and hydrocarbons towards potassium fluoride was checked further by means of radioactive fluorine-18. tracer. Generally, the reaction gave monofluoride together with dehalogenated olefin. The formation of olefine was increased when the reaction was done at high reaction temperature in presence of diethylene glycol, whereas the lower reaction temperature in presence of diethyleneglycol monomethyl ether favored the formation of mono fluoride in a good yield. The procedures and methods of the identification of monofluorides were described and the feasibility of this reaction of fluorine containing ester including the F-18 labelled compounds was discussed.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.631-637
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• 2006

In this study, fundamental properties such as fresh and hardened performance of concrete mix(specification : 25-24-18) added fluorine-silicate hybrid based crack reducing agent(FS) were measured. Addition of FS ranged from 0.5% to 2.0% at intervals 0.5% based on cement weight. Adequate dosage(0.5%) of FS derived from basic properties measurements applied and compared resistance for shrinkage crack. The permeability of concrete in the absence(24-S-0.0) and presence(24-S-0.5) of evaluated at a mock-up sized concrete. Concrete added FS improved resistance for shrinkage crack and consequently crack number, length and area decreased to $50{\sim}74.4%$ compared non-added. As well, by the addition of FS, the resistance for permeability and penetration depth to concrete surface region increased 67% and 40%, respectively. Therefore it was confirmed that shrinkage crack resistance and permeability of concrete could be improved by the addition of FS.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.147-151
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• 2009

Purpose: 2-[$^{18}F$]Fluoro-2-deoxy-D-glucose ([$^{18}F$]FDG) particularly plays as a important role in Positron Emission Tomography (PET) imaging in nuclear medicine. Domestic [$^{18}F$]FDG auto synthesizers are installed in Seoul National University Bundang Hospital (SNUBH) at June 2008, these modules were known that it's synthetic yields were guaranteed in average $45{\pm}5%$ so far. To improve yields and convenience of domestic [$^{18}F$]FDG auto synthesizer, numerous trials in reaction time, base concentration, pressure and temperature were performed to increase [$^{18}F$]FDG yields. Materials and Methods: Several synthetic factors (temperature, time and pressure) and shortcoming were corrected based on many evaporation test. Syringe dispensing of tetra-butylammonium bicarbonate (TBAB) was replaced with micro pipette to prepare tetrabutyl ammonium fluoride salt ([$^{18}F$]TBAF). Troublesome refill of liquid nitrogen every 2 hours which was used to protect vacuum system was changed to charcoal cartridge, base guard filter. To monitor the volume of delivered $[^{18}O]OH_2$ from cyclotron by surveillance camera, we set up the volumetric vial on the cover of the module. In addition to, the recovery vial was added in [$^{18}F$]FDG production system to recover [$^{18}F$]FDG loss due to the leak of valve ($V_{13,14}$) in [$^{18}F$]FDG purification process. Results: When we used micro pipette for adding TBAB ($30\;{\mu}L$ in 12% $H_2O$ in acetonitrile), this quantitative dispensation has enabled to improve $5.5{\pm}1.7%$ residual fluorine-18 activity in fluorine separation cartridge compared to syringe adding. Besides, the synthetic yields of [$^{18}F$]FDG has increased $58{\pm}2.6%$ (n=19), $58{\pm}2.9%$ (n=14), $60%{\pm}2.5%$ (n=17) for 3 months. The life cycle of charcoal cartridge and base vacuum was 3 months prior to filling liquid nitrogen every 2 hours and additional side separator can prevent pump corrosion by organic solvent. After setting of volumetric indicator vial, the operator can easily monitor the total volume of irradiated $[^{18}O]OH_2$ from cyclotron. The recovery vial can be used for the stabilizer when an irregular [$^{18}F$]FDG loss was generated by the leak of valves ($V_{13,14}$). Conclusions: We has optimized appropriate synthetic conditions (temperature, time, pressure) in domestic [$^{18}F$]FDG auto synthesizer. In addition to, the remodeling with several accessories improve yields of domestic [$^{18}F$]FDG auto synthesizer with reliable reproducibility.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.103-115
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• 2008

The purposes of this study are to understand characteristic water-rock interaction mechanisms of groundwater in the granite area of Geochang and Hapcheon areas, Gyeongnam-do and to clarify the origin of fluoride. The possible water-rock interaction process and the source of fluorine were studied using water chemistry, rock chemistry, mineralogy by XRD, and microtexture analysis by backscattered electron image of the electron microprobe. No clear relationships between F and hardness was found. But the fluorine content increases to some extent with pH and well depth. Preferential alteration due to water-rock interaction took place along edges or cleavage, or margins of biotite. Because biotite is highly subject to alteration in granite aquifer, fluorine in groundwater is originated from the leaching of biotite.

• Korean Journal of Materials Research
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• v.27 no.7
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• pp.392-397
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• 2017

Fluorine-doped tin oxide (FTO) coated NiCrAl alloy foam is fabricated using ultrasonic spray pyrolysis deposition (USPD). To confirm the influence of the FTO layer on the NiCrAl alloy foam, we investigated the structural, chemical, and morphological properties and chemical resistance by using USPD to adjust the FTO coating time (12, 18, and 24 min). As a result, when an FTO layer was coated for 24 min on NiCrAl alloy foam, it was found to have an enhanced chemical resistance compared to those of the other samples. This improvement in the chemical resistance of using USPD NiAlCr alloy foam can be the result of the existence of an FTO layer, which can act as a protection layer between the NiAlCr alloy foam and the electrolyte and also the result of the increased thickness of the FTO layer, which enhances the diffusion length of the metal ion.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.73-83
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• 2016

Imaging hypoxia using positron emission tomography (PET) is of great importance for cancer therapy. [$^{18}F$] Fluoromisonidazole (FMISO) was the first PET agent used for imaging tumor hypoxia. Various radiolabeled nitroimidazole derivatives such as [$^{18}F$]fluoroerythronitroimidazole (FETNIM), [$^{18}F$]1-${\alpha}$-D-(2-deoxy-2-fluoroarabinofuranosyl)-2-nitroimidazole(FAZA), 2-(2-nitroimidazol-1-yl)-N-(3,3,3-[18F]-trifluoropropyl)acetamide ([$^{18}F$]EF-3), [$^{18}F$]2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide (EF-5), 3-[$^{18}F$]fluoro-2-(4-((2-nitro-1H-imidazol-1-yl)methyl)-1H-1,2,3,-triazol-1-yl)-propan-1-ol ([$^{18}F$]HX-4), and [$^{18}F$]fluoroetanidazole (FETA) were developed successively. However, these imaging agents still produce PET images with limited resolution; the lower blood flow in hypoxic tumors compared to normoxic tumors results in low uptake of the agents in hypoxic tumors. Thus, the development of better imaging agents is necessary.