• Progress in Superconductivity
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• v.8 no.2
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• pp.143-151
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• 2007

Accurate measurements of the microwave surface resistance (Rs) of high temperature superconductor (HTS) films are important with regard to applications of HTS materials for wireless communications. As the surface resistance values of HTS films are usually extracted from the measured unloaded quality factor ($Q_0$) of resonators made of HTS films, it is essential to measure the resonator $Q_0$ with accuracy. The $TE_{011}\;mode\;Q_0$ of sapphire resonators with the endplates made of $YBa_2Cu_3O_{7-{\delta}}$(YBCO) film on $LaAlO_3$ is measured by using the S-parameter circle-fit method at a frequency of about 19.6 GHz and temperatures of 30 K to 90 K, which is compared with the measured values by using the Lorentzian-fit method. Good agreements are found between the two sets of $Q_0$ values measured by using the two different methods whether the resonator is used in a weak-coupling scheme or a strong-coupling scheme, showing reliability of both methods fur measuring the resonator $Q_0$ accurately. The $Q_0$ of sapphire resonators with a gap between the top plate and the rest of the resonator is also discussed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.149-155
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• 2011

The objective of this study was to evaluate the antioxidant and antigenotoxic activities of sansuyu fruit (Corni fructus, CF) at temperatures of $25^{\circ}C$, $50^{\circ}C$, and $90^{\circ}C$ using a water extraction method. Total phenolic content (TPC), DPPH radical-scavenging activity (RSA), and superoxide dismutase (SOD)-like activity, and ORAC (Oxygen radical absorbance capacity) values were determined. Also the antigenotoxicity of CF was determined by measuring inhibitory effects of $H_2O_2$ induced DNA damage in human leukocytes using the comet assay. The TPC in the CF extracts was 4.2, 4.6, and 5.5 g/100 g GAE in $25^{\circ}C$, $50^{\circ}C$, and $90^{\circ}C$, respectively. The DPPH RSA of the CF extracts increased in a dose-dependent manner over the range of $50\sim1000\;{\mu}g$/mL in all temperatures and the $SC_{50}$ of DPPH RSA of the CF extracts were not significantly different at different extraction temperatures. The $SC_{50}$ of SOD-like was the highest in CF extracted at $25^{\circ}C$ (1.1 mg/mL) followed by $90^{\circ}C$ (1.2 mg/mL) and $50^{\circ}C$ (1.3 mg/mL). The ORAC values of the CF extracts were not significantly different in low concentration ($10\;{\mu}M$/mL) and was in order of $25^{\circ}C$ ($5.7\;{\mu}M$ TE)< $90^{\circ}C$ ($6.2\;{\mu}M$ TE)< $50^{\circ}C$ ($8.5\;{\mu}M$ TE) in high concentration ($50\;{\mu}M$/mL). $200\;{\mu}M$ $H_2O_2$ induced DNA damages in human leukocytes were significantly reduced by the pretreatment with the CF extracts. These results suggest that sansuyu fruit (Corni fructus) can be used as a natural source for antioxidant activities and as antigenotoxic agents regardless of the water extraction temperature.

• Journal of the Korean Applied Science and Technology
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• v.40 no.2
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• pp.223-232
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• 2023

Oxidative stress plays a significant role in the pathogenesis of various skin conditions, resulting in cellular and tissue damage that can contribute to the development of skin tone unevenness, roughness and wrinkles. In this study, we found that Trifolium pratense L. extract (TE) attenuated oxidative-induced damage in HaCaT cells and elucidated the underlying molecular mechanism. Our finding demonstrated that TE effectively protected HaCaT cells against H₂O₂-induced cell death by inhibiting caspase-3 activation, downregulating Bax and upregulating Bcl-2, and attenuating the activation of three mitogen-activated protein kinases (MAPKs). Our results suggest that TE has remarkable cytoprotective properties against oxidative damage in HaCaT cells and could serve as a complementary or alternative approach to prevent and treat skin damage.

• Natural Product Sciences
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• v.21 no.1
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• pp.6-13
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• 2015

Phytochemical investigation of the aerial components of Ducrosia ismaelis Asch. led to the isolation of six known compounds, psoralen (1), isopsoralen (2), cnidioside A (3), (-)-syringaresinol-O-${\beta}$-D-glucopyranoside (4), (E)-plicatin B (5), trilinolein (6). The chemical structures of these compounds were elucidated from spectroscopic data and by comparison of these data with previously published results. The antioxidant, anti-osteoporotic and cardiovascular related activities of the isolated compounds were assessed using oxygen radical absorbance capacity (ORAC), reducing capacity, tartrate-resistant acid phosphatase (TRAP), and soluble epoxide hydrolase (sEH) inhibitory activity assays. Compounds (3-5) showed potent peroxyl radical-scavenging capacities with ORAC values of $11.06{\pm}0.39$, $7.98{\pm}0.10$, and $13.99{\pm}0.06$ Trolox equivalent (TE) at concentrations of $10{\mu}M$, respectively. Only compounds 4 and 5 was able to significantly reduce $Cu^{2+}$ ions, with a reduction value of $9.06{\pm}0.32$ and $4.61{\pm}0.00{\mu}M$ Trolox Equivalent (TE) at a concentration of $10{\mu}M$. Compound 5 at $10{\mu}M$ exhibited a potent inhibitory effect on osteoclastic TRAP activity with a TRAP value of $86.05{\pm}6.55%$ of the control. Compounds 1, 3 and 5 potently inhibited sEH activity with $IC_{50}$ values of 41.6 4.9, 16.0 1.1, and 49.0 $5.7{\mu}M$, respectively.

• Journal of Pharmacopuncture
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• v.18 no.4
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• pp.59-62
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• 2015

Objectives: A previous study showed that bee venom (BV) could cause anaphylaxis or other hypersensitivity reactions. Although hypersensitivity reactions due to sweet bee venom (SBV) have been reported, SBV has been reported to be associated with significantly reduced sensitization compared to BV. Although no systemic immediate hypersensitive response accompanied by abnormal vital signs has been reported with respect to SBV, we report a systemic immediate hypersensitive response that we experienced while trying to use SBV clinically. Methods: The patient had undergone BV treatment several times at other Oriental medicine clinics and had experienced no adverse reactions. She came to acupuncture & moxibustion department at Semyung university hospital of Oriental medicine (Je-cheon, Korea) complaining of facial hypoesthesia and was treated using SBV injections, her first SBV treatment. SBV, 0.05 cc, was injected at each of 8 acupoints, for a total of 0.40 cc: Jichang (ST4), Daeyeong (ST5), Hyeopgeo (ST6), Hagwan (ST7), Yepung (TE17), Imun (TE21), Cheonghoe (GB2), and Gwallyeo (SI18). Results: The patient showed systemic immediate hypersensitive reactions. The main symptoms were abdominal pain, nausea and perspiration, but common symptoms associated with hypersensitivity, such as edema, were mild. Abdominal pain was the most long-lasting symptom and was accompanied by nausea. Her body temperature decreased due to sweating. Her diastolic blood pressure could not be measured on three occasions. She remained alert, though the symptoms persisted. The following treatments were conducted in sequence; intramuscular epinephrine, 1 mg/mL, injection, intramuscular dexamethasone, 5 mg/mL, injection, intramuscular buscopan, 20 mg/mL, injection, oxygen ($O_2$) inhalation therapy, 1 L/minutes, via a nasal prong, and intravascular injection of normal saline, 1 L. After 12 hours of treatment, the symptoms had completely disappeared. Conclusion: This case shows that the use of SBV does not completely eliminate the possibility of hypersensitivity and that patients who received BV treatment before may also be sensitized to SBV. Thus, a skin test should be given prior to using SBV.

• Korean Journal of Materials Research
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• v.9 no.4
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• pp.355-361
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• 1999

We have synthesized the soluble polymide based side chain system with covalently attached NLO chromophore Disperse Red 1. The developed polymer is optically transparent in the range of optical communication wave-lengths. Its glass transition temperature$(T_g)$ and thermal decomposition temperature$(T_d)$ are $225^{\circ}C, 310^{\circ}C$ respectively. The poled film with the poling field of $100 V/\mu\textrm{m}$ shows that the dielectric constant is 3.37 at the 10-kHz frequency, the refractive indices of TM and TE modes are both 1.631 at $\lambda = 1300 nm$, and the Electro-optic coefficients are 4.6~9.2 pm/V at $\lambda = 1300 nm$. There are no decays of the EO coefficient in the poled polymer at $180^{\circ}C$ in one hour, and $90^{\circ}C$ in 500 hours.

• Journal of the Korean institute of surface engineering
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• v.38 no.4
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• pp.144-149
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• 2005

ZnO films were produced on the Si(100) and sapphire(0001) wafers by RF magnetron sputtering in terms of processing variables such as substrate temperature and RF power. The stress in films was obtained from the Stoney's formula using a laser scanning device. The stress levels in the films showed the range from $\~40$ MPa to $\~-1100$MPa depending on processing variables. The specimens were thermally cycled from R.T. to $250^{\circ}C$ to investigate the stress variation as a function of temperature. SEM was employed to characterize the microstructure of te films. As the substrate temperature increased, the film surface became rougher and the films showed coarser grains. The optical property o the films was studied by PL measurements. At the highest substrate temperature $800^{\circ}C$ the film exhibited sharper UV peaks unlike other conditions.

• Asian Journal of Turfgrass Science
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• v.18 no.3
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• pp.141-148
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• 2004

In this report, several factors such as infection time and concentration of bacterial suspension, influencing on transient gene expression in Agrobacterium-mediated transformation were evaluated. An appropriate concentration (O.D 600nm = 1.0-1.2) of bateria and 30 min of infection time showed a higher level of GUS expression. To improve transformation efficiency (TE), friable embryogenic calli (FEC) were bombarded by tungsten particles without plasmid DNA, and then co-cultivated with A. tumefaciens LBA4404 which contains pTOK233 super binary vector, carrying neomycin phosphotransferase (NPTII), hygromycin phosphotransferase (hpt) and$\beta-glucuronidase$ (GUS) genes. Three days after co-cultivation with A. tumefaciens and particle bombardment, FEC cultures were transferred to the selection medium (SM: MS medium supplemented with BA 1mg/l, hygromycin 100mg/l, cefotaxime 250 mg/l and vancomycin 200mg/l). They were cultured for 2 weeks and then transferred to the second SM containing hygromycin 50mg/l, cefotaxime 200 mg/l and vancomycin 100mg/l. Later, stable GUS expression was detected 4 to 6 weeks after transfer to the SM. Further, TE from Agrobacterium-mediated transformation after particle bombardment increased to about 3-folds compared with Agrobacterium-mediated transformation without particle bombardment. In the present study, we established an efficient transformation protocol of zoysiagrass by using A. tumefaciens in the combination with particle bombardment for the first time.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.1
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• pp.70-78
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• 2000

In applying high-${\underline{T_c}}$ superconducting material to microwave devices, Uncertainty of electromagnetics of high-${\underline{T_c}}$ superconductor(HTS) and the temperature dependence of the substrate fits with HTS thin film cause difficulty in realization of such antenna for industrial applications. It must be noted to characteristic the HTS antenna in contrast with normal conducting counterpart for this real application. In this paper, a comparative study between HTS microstrip antennas and gold antennas was reported in terms of the return loss, the characteristic impedance, efficiency, and other various characteristics. HTS thin films were $YBa_2Cu_3O_{7-x}$ (YBCO) on MgO substrates. Superconducting microstrip antennas used in this work were to directly inset a microstrip transmission line into the 50 ${\Omega}$ region of the radiating patch. Measurement results of HTS antennas and gold antennas showed that usable antennas can be made using this architecture.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.1
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• pp.63-69
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• 2000

The high-$T_c$ Superconducting (HTS) antenna which consists of "H" type resonator has the benefits for the miniaturization of antenna in comparison with the microstrip antenna of the similar dimension. To fabricate the "H" type antenna, HTS $YBa_2Cu_3O_{7-x}$ (YBCO) thin films were deposited on MgO substrates using rf-magnetron sputtering. Standard etching processes were performed for the patterning of the "H" type antenna. For comparison between normal conducting antennas and superconducting antennas, the gold antennas with the same dimension were also fabricated. An aperture coupling was used for impedance matching between $50{\Omega}$ feed line and HTS radiating patch. The diverse experimental results were reported in terms of the resonant frequency, the return loss and the characteristics impedance. The "H" type superconducting antenna showed the performance of 1.36 in SWR, 24% in efficiency, and 14.6 dB in the return loss superior of the normal conducting counterpart.