• Journal of Radiopharmaceuticals and Molecular Probes
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• v.3 no.2
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• pp.91-97
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• 2017

$^{18}F-THK-5351$ is a PET radiotracer to image the hyperphosphorylated tau fibrillar aggregates in human brain. This protocol describes the optimized radiosynthesis of $^{18}F-THK-5351$ using a commercial GE $TRACERlab^{TM}$ $FX_{FN}$ radiosynthesis module. $^{18}F-THK-5351$ was prepared by nucleophilic [$^{18}F$]fluorination from its protected tosylate precursors, (S)-(2-(2-methylaminopyrid-5-yl)-6-[[2-(tetrahydro-2H-pyran-2-yloxy)-3-tosyloxy]propoxy] quinolone(THK-5352), at $110^{\circ}C$ for 10 min in dimethyl sulfoxide, followed by deprotection with 1 N HCl. The average radiochemical yield of $^{18}F-THK-5351$ was $31.9{\pm}6.7%$(decay-corrected, n = 10), with molar activity of $198.1{\pm}33.9GBq/{\mu}mol$($5.4{\pm}0.9Ci/{\mu}mol$, n = 10). The radiochemical purity was determined to be above 98%. The overall production time including HPLC purification is approximately 70 min. This fully-automated protocol is validated for clinical use.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2477-2480
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• 2014

Thermal degradation of titanium-containing metal-organic frameworks (MOFs; MIL-125 and MIL-125-$NH_2$ at $350^{\circ}C$ for 6 h in air produced $TiO_2$ nanoparticles of ca. 10 nm in diameter. Scanning electron and transmission electron microscope analyses indicated that those nanoparticles were aggregated randomly within each crystalline particle of their MOF precursors. The $TiO_2$ nanoparticles prepared from MIL-125-$NH_2$ exhibited higher activity for the degradation of 4-chlorophenol under visible light.

• International Journal of Oral Biology
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• v.38 no.2
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• pp.67-72
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• 2013

This study examined the anti-osteoclastogenic effects of baicalin on receptor activator of NF-${\kappa}$B ligand (RANKL)-induced RAW264.7 cells. Baicalin is a flavonoid that is produced by Scutellaria baicalensis and is known to have multiple biological properties, including antibacterial, anti-inflammatory and analgesic effects. The effects of baicalin on osteoclasts were examined by measuring 1) cell viability; 2) the formation of tartrate-resistant acid phosphatase (TRAP) (+) multinucleated cells; 3) RANK/RANKL signaling pathways and 4) mRNA levels of osteoclast-associated genes. Baicalin inhibited the formation of RANKL-stimulated TRAP (+) multinucleated cells and also suppressed the RANKL-stimulated activation of p-38, ERK, cSrc and AKT signaling. Baicalin also inhibited the RANKL-stimulated degradation of $I{\kappa}B$ in RAW264.7 cells. In addition, the RANKL-stimulated induction of NFATc1 transcription factors was found to be abrogated by this flavonoid. Baicalin was further found to decrease the mRNA expression of osteoclast-associated genes, including carbonic anhydrase II, TRAP and cathepsin K in the RAW264.7 cells. Our data thus demonstrate that baicalin inhibits osteoclastogenesis by inhibiting the RANKL-induced activation of signaling molecules and transcription factors in osteoclast precursors.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.613-619
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• 2003

The polyketide backbone of rifamycin B is assembled by the type I rifamycin polyketide synthase (PKS) encoded by the rifA-rifE genes. In order to produce novel analogs of rifamycin via engineering of the PKS genes, inactivation of the ${\beta}-ketoacyl:acyl$ carrier protein reductase (KR) domain in module 8 of rifD, by site-specific mutagenesis of the NADPH binding site, was attempted. Module 8 contains a nonfunctional dehydratase (DH) domain and a functional KR domain that is involved in the reduction of the ${\beta}-carbonyl$ group, resulting in the C-21 hydroxyl of rifamycin B. This mutant strain produced linear polyketides, from tetraketide to octaketide, which were also produced by a rifD-disruption mutant as a consequence of premature termination of the polyketide assembly. Another attempt to replace the DH domain of module 7, which has been considered nonfunctional, with a functional homolog derived from module 7 of rapamycin-producing PKS also resulted in the production of linear polyketides, including the heptaketide intermediate and its precursors. Premature release of the carbon chain assembly intermediates is an unusual property of the rifamycin PKS. that is not seen in other PKSs such as the erythromycin PKS.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.1-6
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• 2010

The purpose of this study is to synthesize the radio fluorine labelled isoquinoline salt derivative as new radiopharmaceutical for imaging tumors using positron emission tomography (PET). The planarity of isoquinoline allows to inhibit topoisomerase or intercalate between adjacent DNA base pairs, which result in producing double strand breaks in the DNA and a cell death. Therefore, the isoquinoline has seemed to have a potential anticancer activity. In order to obtain 2-(5-[$^{18}F$]fluoropentylisoquinolinium salt with good radiochemical yield, tosylated precursors have been synthesized. The labelling reaction was carried out for 30 minute in HMPA at $120^{\circ}C$. The radiochemical yield was about 50~60%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.6
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• pp.238-244
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• 2007

Nano-sized ZnO crystals were successfully incorporated using ion exchange method in TMA-A zeolite synthesized by the hydrothermal method. The optimal composition for the synthesis of TMA-A zeolite was resulted in a solution of $Al(i-pro)_3$:2.2 TEOS:2.4 TMAOH:0.3 NaOH:200 $H_2O$. 0.3g of TMA-A zeolite and 5mol of $ZnCl_2$ solution were employed for the preparation of ZnO incorporated TMA-A zeolite. The ZnO incorporated TMA-A zeolite precursors, prepared from the process of mixing, stirring, centrifugal separation and drying, were calcined at temperatures from 400 to $600^{\circ}C$ for 3 h. The crystallization process of ZnO incorporated TMA-A zeolite was analyzed by X-ray diffraction (XRD). The Brunaur-Emett-Teller (BET) surface area of the ZnO incorporated TMA-A zeolite was measured. Subsequently, the morphology and the particle size depending on the temperature and time were observed using scanning electron microscopy(SEM), transmission electron microscopy(TEM) and particle size analyzer.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.369-375
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• 2010

The study on the characteristics of nitrous oxide catalytic decomposition was carried out to utilize the nitrous oxide as a propellant. The Pt, Ir and Ru were synthesized to select a high performance catalyst for the nitrous oxide decomposition reaction. The respective catalyst precursors were loaded in the $Al_2O_3$ support using an wet impregnation method. The $N_2O$ conversion as a variation of space velocity and reaction temperature was measured using a tubular reactor. The catalyst loss was measured to evaluate the durability of catalysts after the reaction at $800^{\circ}C$ for 2 hours. The $N_2O$ conversion was increased at the decrease of space velocity and at the increase of temperature. The Ru/$Al_2O_3$ catalyst had the highest $N_2O$ conversion at low temperature and the best durability.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.27-32
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• 2011

Tin nanoparticles were synthesized at room temperature by a compulsive reduction reaction using tin(II) acetate and tin(II) chloride precursors. When an identical amount (0.015 g) of polyvinyl pyrrolidone (PVP) was added, it was concluded that the probability of abnormally big particles forming increased with an increase in PVP molecular weight, resulting in the wide distribution of Sn nanoparticles. Differential scanning calorimetry measurements were carried out using diethylene glycol solution containing synthesized tin nanoparticles. When the population of specific particles with sizes below 35 nm was adequate, the melting point depression peaks of tin nanoparticles corresponding to the specific size were observed besides an evaporation endothermic peak of DEG during the first heating. Because DEG was evaporated and tin nanoparticles in contact became molten and coarsened during the first heating, a melting peak of bulk tin was only observed at $232^{\circ}C$ during the second heating.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.818-823
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• 1992

2-Ethylhexanoate compounds which contained Y, Er, Yb, Ba, and Cu were prepared separately. These metallo-organic compounds were dissolved together in the common solvent and the solution was homogeneous. From these solution, high $T_c$ superconductors $YBa_2Cu_3O_{7-\delta}(Y_{123})$, $ErBa_2Cu_3O_{7-\delta}(Er_{123})$, and $YbBa_2Cu_3O_{7-\delta}(Yb_{123})$ were prepared. XRD analysis showed that these superconductors were not single phase and contained some impurity phases including $YBa_2Cu_4O_8(Y_{124})$. This was also confirmed from the magnetic susceptibility measurement. Generally, critical temperatures were higher than that of the superconductors prepared by ceramic method. Volume diamagnetic susceptibility showed little variation compared to the specimen made by ceramic method.

• Corrosion Science and Technology
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• v.20 no.4
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• pp.183-188
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• 2021

The increasing demand for energy storage in mobile electronic devices and electric vehicles has emphasized the importance of electrochemical energy storage devices such as Li-ion batteries (LIBs) and supercapacitors. For reversible Li storage, alternative anode materials are actively being developed. In this study, we designed and fabricated an Nb₂O₅-Li₃VO₄ composite for use as an anode material in LIBs and hybrid supercapacitors. Nb₂O₅ powders were dissolved into a solution and the precursors were precipitated onto Li₃VO₄ through a simple, low-temperature hydrothermal reaction. The annealing process yielded an Nb₂O₅-Li₃VO₄ composite that was characterized by X-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy. Electrochemical tests revealed that the Nb₂O₅-Li₃VO₄ composite electrode demonstrated increased capacities of approximately 350 and 140 mAh g^-1 at 0.1 and 5 C, respectively, were maintained up to 1000 cycles. The reversible capacity and rate capability of the composite electrode were enhanced compared to those of pure Nb₂O₅-based electrodes. These results can be attributed to the microstructure design of the synthesized composite material.