• Food Science and Biotechnology
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• 제18권1호
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• pp.143-149
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• 2009

The aim of this study was to elucidate the anti-inflammatory activity of safflower (Carthamus tinctorius L.) ethanolic extract fractions (CFEFs). Butanol fraction had the strongest antioxidant activity, and all CFEFs, except for chloroform fraction, partly inhibited lipopolysaccharide (LPS)-induced nitrite production in RAW 264.7 cells. In the cell-free system, hexane and butanol fractions chemically quenched nitric oxide (NO). In addition, the iNOS mRNA transcription was suppressed by ethanol extract and hexane fraction in LPS-stimulated RAW 264.7 cells. Taken together, the inhibitory effect of CFEFs on NO production from LPS-stimulated RAW 264.7 cells, might be due to both the chemical NO quenching activity and the suppression of iNOS mRNA transcription partially. The synthesis of prostaglandin $E_2$ ($PGE_2$) was potently inhibited by ethanol extract to below basal label, and the transcription of cyclooxygenase-2 (COX-2), an enzyme involving in $PGE_2$ synthesis, was partially suppressed by ethanol extract and hexane fraction. Based on these results, CFEFs may be useful as an alternative medicine for the relief and retardation of immunological inflammatory responses through the reduction of inflammatory mediators, including NO and $PGE_2$ production.

• Food Science and Biotechnology
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• 제18권1호
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• pp.1-11
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• 2009

Carotenoids being most important pigments among those occurring in nature, have received increased interest owing to their beneficial effects on human health. An effort is made to review marine carotenoids as important bioactive compounds with reference to their presence, chemical, and biofunctional benefits they afford. The potential beneficial effects of marine carotenoids were particularly focused on astaxanthin and fucoxanthin, major marine carotenoids found in marine animals and aquatic plants, respectively. Both carotenoids show strong antioxidant activity which is attributed to quenching singlet oxygen and scavenging free radicals. The potential role of the carotenoids as dietary antioxidants has been suggested as being one of the main mechanism by which they afford their beneficial health effects such as anticancer activity and anti-inflammatory effect. Only recently, antiobesity effect and antidiabetic effect have been noted as specific and novel bio-functions of fucoxanthin. Nutrigenomic study reveals that fucoxanthin induces uncoupling protein 1 (UCP1) expression in white adipose tissue (WAT) mitochondria to lead to oxidation of fatty acids and heat production in WAT. Fucoxanthin improves insulin resistance and decreases blood glucose level, at least in part, through the down-regulation of tumor necrosis factor $\alpha$ ($TNF{\alpha}$) in WAT of animals.

• 한국주조공학회지
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• 제29권5호
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• pp.213-219
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• 2009

Optimum conditions for production of semi-solid Al-Zn-Mg alloy billets was carried out by the Taguchi design method. And, Al-Zn-Mg alloy billets contained Sc (free, 0.1 and 0.3 mass %) were fabricated at optimum conditions. Evolution of microstructure in semi-solid state was investigated through various liquid fractions, holding times and holding temperatures. The Al-Zn-Mg alloy billets reheated at $615^{\circ}C$ during 30min are grain growth and it was fractured due to increasing liquid fraction before quenching. And, during reheating up to $600^{\circ}C$, grain growth of Al-Zn-Mg alloy billets contained Sc (0.1 and 0.3 mass %) was not occurred in comparison with those of Al-Zn-Mg alloy without Sc. It was thought that $Al_3Sc$ phases have a pinning effect in grain boundary and Sc content of 0.1 mass% is able to inhibit grain growth effectively through reheating process.

• Journal of Magnetics
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• 제8권1호
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• pp.18-23
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• 2003

In our previous work, microstructure and magnetic properties of two-phase exchange-coupled $Sm_2Fe_{15}Ga_2C_{x}$/$\alpha$-Fe nanocomposites have been investigated by means of x-ray diffraction, transmission electron microscopy and magnetization measurement. It was found the exchange coupling between the magnetically hard phase $Sm_2Fe_{15}Ga_2C_{x}$ and the magnetically soft one ${\alpha}$-Fe results in an enhancement of the remanence. The sizes of crystallites of both phases are, however much larger than the Block domain-wall width of the magnetically hard phase. This microstructure gives rise to a concave demagnetization curve and consequently reduces the maximum energy Product. In order to improve their magnetic properties, a few Percent of Zr, which may be effective to refine the microstructure through rapid quenching, was introduced into the nanocomposites. The addition of Zr was found to improve the magnetic properties significantly, Under optimum heat-treatment conditions, the remanence, coercivity and maximum energy Product increase from 0.65 T, 0.48 T and 50 kJ/$m^{3}$ for the Zr-free sample to 0.72 T, 0.77 T and 71.6 kJ/$m^{3}$ for the 1 at.% Zr-containing one, respectively, The improvements of magnetic properties are due to the refinement of microstructure by the addition of Zr.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1574-1576
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• 1994

$SF_6$ gas has become an important insulation medium in modern electric power apparatus, because of its high insulation withstand levels and good arc quenching capability. For the application of $SF_6$ gas in GIS the estimation of insulation properties is a fundamental point. Moreover the reduction of withstand levels in case of inhomogeneous fields caused by particles or fixed protrusions is of special interest. It is known that the presence of free conducting particles in GIS can significantly lower the insulating level of $SF_6$ gas at elevated pressure and also it has been recently shown that dielectric strength is greatly reduced by fast transients such as disconnector surges where metallic particles are involved. In this paper, we have disigned the particle test chamber rated 362kV for the purpose of investigating the discharge characteristics in SF6 gas where inhomogenius fields are caused by metallic particles.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.91-91
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• 2008

$SnO_2-B_2O_3-P_2O_5$ system were prepared by melt-quenching technique in the compositional series containing 50, 55 aod 60mol.% of $SnO_2$. A large glass-forming region was found at the phosphate side of the ternary system with homogeneous glasses containing up to 5-25mol.% of $B_2O_3$. For these glasses, thermal expansion coeffient($\alpha$), glass transition temperature(Tg), and glass softening temperature(Ts), were determined. The values a decrease with increasing $B_2O_3$ content, while Tg and Ts increased. The reason for the observed changes is local structure of the glasses. Local structure of the glasses was investigated by Raman and FT-IR measurements, suggesting that the number of bridging oxygens decreased whereas the non-bridging oxygen concentration increased with increasing $SnO_2$ content in the glasses.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.2025-2037
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• 2021

The influence of lead cations on natural quartz (QZ) from Egypt as a glass shielding material for the composition with nominal formula (10Na₂O - (90 - x) QZ - xPbO (where x = 30, 35, 40, 45 and 50 mol %)) was examined. The studied samples are synthesized via the melt quenching method at 1050 ℃. The X-ray diffraction XRD patterns were confirmed the glass nature for studied samples. Moreover, the optical properties, and the transparency for all compositions were examined by UV-Vis spectroscopy. Also, the major elemental composition of the natural quartz were estimated via the X-ray fluorescence (XRF) technique. Further, the density and molar volume were determined. Furthermore, the nuclear shielding parameters such as, mass attenuation coefficient, effective atomic number, electronic density, the total atomic, and electronic cross sections as well as the mean free path, and the half value layer with different gamma ray energies (81 keV-1407 keV) were calculated. Besides, the results showed that the shielding behavior towards the gamma ray radiation for all glass samples was increased as the increment in PbO concentration in the glass system.

• 열처리공학회지
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• 제35권4호
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• pp.177-184
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• 2022

The present study aims to investigate the influence of Zn addition on hardness and microstructural characteristics of discontinuous precipitates (DPs) formed by isothermal aging in Mg-9%Al and Mg-9%Al-1%Zn alloys. To obtain large DPs volume fractions in the microstructure, the alloy specimens were solution-treated at 688 K for 24 h followed by water quenching, and then aged at 413 K for 48 h. The aged Mg-9%Al-1%Zn alloy had higher DPs content than the Mg-9%Al alloy, indicating that the Zn addition plays a beneficial role in enhancing age-hardening response. The DPs in the Zn-containing alloy possessed the higher hardness than those of the Zn-free alloy. Microstructural examination revealed that the increased hardness of the DPs resulting from the Zn addition is closely associated with the lower α-(Mg)/β(Mg₁₇Al₁₂) interlamellar spacing and the higher volume fraction of β phase layer of the DPs.

• Journal of Ginseng Research
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• 제41권3호
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• pp.330-338
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• 2017

Background: Ginsenoside Rh2 (G-Rh2) is a ginseng saponin that is widely investigated because of its remarkable antitumor activity. However, the molecular mechanism by which (20S) G-Rh2 triggers its functions and how target animals avoid its cytotoxic action remains largely unknown. Methods: Phage display was used to screen the human targets of (20S) G-Rh2. Fluorescence spectroscopy and UV-visible absorption spectroscopy were used to confirm the interaction of candidate target proteins and (20S) G-Rh2. Molecular docking was utilized to calculate the estimated free energy of binding and to structurally visualize their interactions. MTT assay and immunoblotting were used to assess whether human serum albumin (HSA), bovine serum albumin (BSA), and bovine serum can reduce the cytotoxic activity of (20S) G-Rh2 in HepG2 cells. Results: In phage display, (20S) G-Rh2-beads and (20R) G-Rh2-beads were combined with numerous kinds of phages, and a total of 111 different human complementary DNAs (cDNA) were identified, including HSA which had the highest rate. The binding constant and number of binding site in the interaction between (20S)-Rh2 and HSA were $3.5{\times}10^5M^{-1}$ and 1, and those in the interaction between (20S) G-Rh2 and BSA were $1.4{\times}10^5M^{-1}$ and 1. The quenching mechanism is static quenching. HSA, BSA and bovine serum significantly reduced the proapoptotic effect of (20S) G-Rh2. Conclusion: HSA and BSA interact with (20S) G-Rh2. Serum inhibited the activity of (20S) G-Rh2 mainly due to the interaction between (20S) G-Rh2 and serum albumin (SA). This study proposes that HSA may enhance (20S) G-Rh2 water solubility, and thus might be used as nanoparticles in the (20S) G-Rh2 delivery process.

• 대한약리학회지
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• 제18권2호
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• pp.89-102
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• 1982

The $Na^+-and\;K^+-induced\;Ca^{++}$ release was measured isotopically by millipore filter technique in pig heart mitochondria. With EGTA-quenching technique, the characteristics of mitochondrial $Ca^{++}-pool$ and the sources of $Ca^{++}$ released from mitochondria by $Na^+\;or\;K^+$ were analyzed. The mitochondrial $Ca^{++}-pool$ could be distinctly divided into two components: internal and external ones which were represented either by uptake through inner membrane, or by energy independent passive binding to external surface of mitochondria, respectively. In energized mitochondria, a large portion of $Ca^{++}$was transported into internal pool with little external binding, while in de-enerigzed state, a large portion of transported $Ca^{++}$ existed in the external pool with limited amount of $Ca^{++}$ in the internal pool which was possibly transported through the $Ca^{++}-carrier$ present in the inner membrane. $Na^+$ induced the $Ca^{++}$ release from both internal pool and external pool and external binding pool of mitochondria. In contrast, $K^+$ did not affect $Ca^{++}$ of the internal pool, but, displaced $Ca^{++}$ bound to external surface of the mitochondria. When the $Ca^{++}-reuptake$ was blocked by EGTA, the $Ca^{++}$ release from the internal pool by $Na^+$ was rapid; the rate of $Ca^{++}-efflux$ appeared to be a function of $[Na^+]^2$ and about 8mM $Na^+$ was required to elicit half-maximal velocity of $Ca^{++}-efflux$. So it was revealed that $Ca^{++}-efflux$ velocity was particulary sensitive to small changes of the $Na^+$ concentration in physiological range. Energy independent $Ca^{++}-binding$ sites of mitochondrial external surface showed unique characteristics. The total number of external $Ca^{++}-binding$ sites of pig heart mitochondria was 29 nmoles per mg protein and the dissociation constant(Kd) was $34{\mu}M$. The $Ca^{++}-binding$ to the external sites seemed to be competitively inhibited by $Na^+\;and\;K^+$; the inhibition constant(Ki) were 9.7 mM and 7.1 mM respectively. Considering the intracellular ion concentrations and large proportion of $Ca^{++}$ uptake in energized mitochondria, the external $Ca^{++}-binding$ pool of the mitochondria did not seem to play a significant role on the regulation of intracellular free $Ca^{++}$ concentration. From this experiment, it was suggested that a small change of intracellular free $Na^+$ concentration might play a role on regulation of free $Ca^{++}$ concentration in cardiac cell by influencing $Ca^{++}-efflux$ from the internal pool of mitochondria.