• The Korean Journal of Physiology and Pharmacology
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• v.2 no.5
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• pp.549-553
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• 1998

Using the planar lipid bilayer method, we investigated the effect of d-tubocurarine (dTC) on the extracellular side of large-conductance $Ca^{2+}-activated\;K^+$ channel from rat brain. When the initial open probability (Po) of the channel was relatively high, dTC decreased channel activity in a concentration dependent manner. In contrast, when the initial Po was lower, sub-micro molar dTC increased channel activity by destabilizing the closed states of the channel. Further addition of dTC up to micro molar range decreased channel activity. This dual effect of dTC implicates that there exist at least two different binding sites for dTC.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.69-74
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• 2001

Purpose: $^{99m}Tc$-HMPAO is a radiopharmaceutical for imaging cerebral blood flow. HMPAO (RR, SS)-4.8-diaza-3,6,6,9-tetramethylundecan-2,10- dione bisoxime) has three stereoismers such as, meso-. d-, and l-HMPAO. Techentium complexes of meso-HMPAO and d,l-HMPAO are known to have different in vivo brain uptakes. In this study, enantiomers of HMPAO (d-HMPAO and l-HMPAO) were separated from d,l-HMPAO. These enantiomers were labeled with $^{99m}Tc$ and the biodistribution studies were performed in mice. Materials and Methods: An intermediate imine product was produced from 2,3-butanedione monooxime and 2,2-dimethyl-1,3-propanediamine (54% yield) and was reduced into a mixture of three isomers (35% yield). The meso-isomer was separated from d,l-mixture by repeated fractional crystallization (11 % yield). The d- and l-enantiomers were subsequently separated by co-crystallization with optical isomers of tartaric acid (25% and 5% yield. respectively). Each enantiomeric HMPAO was labeled with $^{99m}Tc$ by reacting with $SnCI_2{\cdot}2H_2O\;and\;^{99m}Tc$-pertechnetate. Biodistribution study was performed 1 hr after tail vein injection to ICR mice. Results: Radiochemical purities of each compound were over 80%. In biodistribution study. the brain uptakes of d,l- d- and l-form were 1.34, 1.12 and 1.67% ID/g, respectively. In case of l-lsomer the brain uptake was higher (1.5 fold) than d-isomer. Conclusion: We successfully purified each enantiomeric HMPAO. In biodistribution study of stereoismers of $^{99m}Tc$-HMPAO in mice, l-HMPAO may show better brain image than d,l-HMPAO which was supplied in a commercial kit.

• BMB Reports
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• v.40 no.5
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• pp.625-635
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• 2007

The enzyme squalene synthase (EC 2.5.1.21) catalyzes a reductive dimerization of two farnesyl diphosphate (FPP) molecules into squalene, a key precursor for the sterol and triterpene biosynthesis. A full-length cDNA encoding squalene synthase (designated as TcSqS) was isolated from Taxus cuspidata, a kind of important medicinal plants producing potent anti-cancer drug, taxol. The full-length cDNA of TcSqS was 1765 bp and contained a 1230 bp open reading frame (ORF) encoding a polypeptide of 409 amino acids. Bioinformatic analysis revealed that the deduced TcSqS protein had high similarity with other plant squalene synthases and a predicted crystal structure similar to other class I isoprenoid biosynthetic enzymes. Southern blot analysis revealed that there was one copy of TcSqS gene in the genome of T. cuspidata. Semi-quantitative RT-PCR analysis and northern blotting analysis showed that TcSqS expressed constitutively in all tested tissues, with the highest expression in roots. The promoter region of TcSqS was also isolated by genomic walking and analysis showed that several cis-acting elements were present in the promoter region. The results of treatment experiments by different signaling components including methyl-jasmonate, salicylic acid and gibberellin revealed that the TcSqS expression level of treated cells had a prominent diversity to that of control, which was consistent with the prediction results of TcSqS promoter region in the PlantCARE database.

• Polymer(Korea)
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• v.29 no.2
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• pp.161-165
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• 2005

$\alpha,\omega-Vinyl$ poly(dimethyl-methylphenyl) siloxane propelymer (VPMPS ) was prepared by the equilibrium polymerization of octamethylcyclotetrasiloxane $(D_4)$, 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane $(D_3^{MePh})$, and 1,1,3,3-tetramethyl-1,3-divinylsiloxane (MVS) as end-blocker. And also, $\alpha,\omega-hydrogen$ poly(dimethyl-methyltrifluoropropyl)siloxane prepolymer (HPDMFS) was prepared from $D_4$, 1,3,5-trimethyl-1,3.5-trifluoropropylcyclotrisiloxane $(D_3^{MeF3P})$, and 1,1,3,3-tetramethyldisiloxane. Poly(organosiloxane) rubber composite containing high thermal conductive filler was prepared by compounding VPMPS, HPDMFS, spherical alumina, and catalyst in high speed dissolver. The crosslinking density of poly (organosiloxane) composite was measured by oscillation rheometer. Poly(organosiloxane) composites of TC-POXR-2 and TC-POXR-4 prepared by controlling average diameters of thermal conductive filler, spherical alumina according to Horsfield's packing model were shown to 1.13 W/mK for TC-POXR-2 and 1.19 W/mK for TC-POXR-4.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.1
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• pp.89-94
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• 2018

In this study, water-dispersed biocellulose nanofibers (TC) were prepared via an oxidation reaction using 2,2,6,6-tetramethyl-1-piperidine-N-oxy radical (TEMPO) as a catalyst. The TC retained their unique structure in water as well as in emulsion. TC adhered to the skin surface while maintaining nanofibrous structures, providing inherent functions of biocellulose, such as high tensile strength and high water-holding capacity. When gelatin gels as model skin were coated with TC, the hardness representing the elasticity was increased by 20% compared to untreated gelatin gel because TC could tightly hold the gelatin structure. When porcine skin was treated with TC and TC-contained O/W emulsion, the initial water contact angles of TC were lower than other materials, and dramatically decreased over time as water penetrated the fibrous structure of the TC film. Characterization of TC on the skin surface offered insight into the function of nanofibers on the skin, which is important for their applications with respect to fiber-cosmetics.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.61-66
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• 2009

Purpose: Glomerular filtration rate (GFR) is considered as the best overall index for the level of renal function, diagnosis of doubtful kidney disease, progress observation from chronic kidney disease and is measured with the various methods. In this study, We measured standard GFR by Gates method and attempted to compare the result with serum creatinin-based, Cockcroft-Gault(C-G) formula and Modification of Diet in Renal Disease (MDRD) formula. Materials and methods: 217 patients (127 men, 90 women, mean age $51.3{\pm}16.9$) with various renal function were examined. we compared the GFR using $^{99m}Tc$-DTPA (Gates), C-G formula and MDRD formula. Results: Significant correlations were noted between 2 different GFR estimates (from C-G formula: r=0.864, p<0.0001, MDRD formula: r=0.831, p<0.0001) and $^{99m}Tc$-DTPA (Gates) GFR. Average of serum creatinine (Scr) was measured with $3.0{\pm}3.1\;mg/dL$, In patients with normal renal function (Scr<1.5 mg/dL), $^{99m}Tc$-DTPA (Gates) GFR was statistically significant to C-G formula (p<0.0001) and MDRD formula (p<0.0001). In patients with mild to moderate renal insufficiency (1.5$^{99m}Tc$-DTPA (Gates) GFR was not statistically significant to C-G formula (p=0.181) and MDRD formula (p=0.127). In patients with severe renal insufficiency (Scr>4.0mg/dL), $^{99m}Tc$-DTPA (Gates) GFR was statistically significant to C-G formula and MDRD formula (p<0.0001). Conclusions: Glomerular filtration rate using Gates method was closly correlated to C-G formula and MDRD formula. In patients with normal renal function, $^{99m}Tc$-DTPA (Gates) GFR was significantly lower than C-G formula and MDRD formula. In patients with mild to moderate renal insufficiency, $^{99m}Tc$-DTPA (Gates) GFR was simmilar with C-G formula and MDRD formula. In patients with severe renal insufficiency, $^{99m}Tc$-DTPA (Gates) GFR was significantly higher than C-G formula and MDRD formula. None of the three different methods was clearly superior to the others.

• Proceedings of the Korean Magnestics Society Conference
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• 1999.10a
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• pp.70-71
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• 1999

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.11
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• pp.1142-1155
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• 2014

The classical PCM/PSK/PM scheme has been commonly used for TC & R applications between satellites and ground stations in the S-band. We analyzed TC & R link performance between ground station and the geostationary satellite which employs PCM/PSK/PM, when the satellite are particularly on the Super Synchronous Transfer Orbit(SSTO). The satellite parameters on SSTO are assumed to be those operating on the geostationary orbit, considering heritage aspect. In the uplink, the results shown indicate that sufficient margins over 3 dB are obtained when the EIRP of ground station is greater than 65 dBW. The down link performance is of great interest. By adjusting the telemetry modulation index and ranging modulation index, we could obtain the required margin of 3.0 dB in the down link, and find out the minimum G/T of ground station. In conclusion, the previously operated ground stations during LEOP at COMS launch, can be operational when GEO injection is made using SSTO(65,000 km and 70,000 km).

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1189-1193
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• 2006

In order to develop radiopharmaceuticals for targeting a serotonin receptor such as $5-HT_{1A}$, histidine-$C_n$-arylpiperazines (AP) (C = alkyl, n = 2, 3, 4) were prepared in five steps with yields of 25%, 37% and 51%, respectively, and radiolabeled with the $[^{99m}Tc(CO)_3(H_2O)+3]^+$. The $^{99m}Tc(CO)_3$-Histidine-Cn-APs were prepared with a high yield (>99%) and characterized as a tridentate complex with a neutral charge to pass through the blood-brain barrier (BBB). The rhenium complexes with $Re(CO)_3$ were also synthesised and comparative experiments were achieved to evaluate the nature of the $^{99m}Tc$ complexes.

• Health Policy and Management
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• v.29 no.3
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• pp.357-367
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• 2019

Background: This study evaluated the cost-effectiveness of 21 different national dyslipidemia screening strategies according to total cholesterol (TC) cutoff and screening interval among 40 years or more for the primary prevention of coronary heart disease over a lifetime in Korea, from a societal perspective. Methods: A decision tree was used to estimate disease detection with the 21 different screening strategies, while a Markov model was used to model disease progression until death, quality-adjusted life years (QALYs) and costs from a Korea societal perspective. Results: The results showed that the strategy with TC 200 mg/dL and 4-year interval cost \4,625,446 for 16.65105 QALYs per person and strategy with TC 200 mg/dL and 3-year interval cost \4,691,771 for 16.65164 QALYs compared with \3,061,371 for 16.59877 QALYs for strategy with no screening. The incremental cost-effectiveness ratio of strategy with TC 200 mg/dL and 4-year interval versus strategy with no screening was \29,916,271/QALY. At a Korea willingness-to-pay threshold of \30,500,000/QALY, strategy with TC 200 mg/dL and 4-year interval is cost-effective compared with strategy with no screening. Sensitivity analyses showed that results were robust to reasonable variations in model parameters. Conclusion: In this study, revised national dyslipidemia screening strategy with TC 200 mg/dL and 4-year interval could be a cost-effective option. A better understanding of the Korean dyslipidemia population may be necessary to aid in future efforts to improve dyslipidemia diagnosis and management.