• Biomolecules & Therapeutics
• /
• v.17 no.4
• /
• pp.455-460
• /
• 2009

Foods of plant origin, especially fruits and vegetables, have attracted attention because of their potential benefits to human health. In this report, Rubi Fructus (RF), the dried unripe fruit of Rubus coreanus Miq (Rosaceae) and ellagic acid (EA) purified from RF were used to test their potential hepatoprotective effect against acetaminophen (AAP)-induced hepatotoxicity in rats. RF extract (RFext) and EA reduced the elevated levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) in serum and the content of lipid peroxide in liver by AAP administration, while the increment of the cellular glutathione (GSH) content and the induction of glutathione S-transferase (GST) and glutathione peroxidase (GSH-PX) which were decreased by AAP administration. RFext and EA from RFext did not affect the two major form of cytochrome P450s, cytochrome P450 2E1 (CYP2E1) and cytochrome P450 1A2 (CYP1A2), but downregulated the cytochrome P450 3A4 (CYP3A4) related to the conversion of AAP to N-acetyl-P-benzoquinone imine (NAPQI). These results suggest that RFext and EA from RF exhibit a hepatoprotective effect not only by increasing antioxidant activities but also by down-regulating CYP3A4 in the AAP-intoxicated rat.

• Journal of Advanced Navigation Technology
• /
• v.15 no.5
• /
• pp.789-794
• /
• 2011

This paper has analyzed the AM-AM and AM-PM characteristics of 7.9 GHz~8.4 GHz X-band TWT used for satellite communication and improved its linearity and IMD performance by using linearizer. The TWT amplifier with the linearizer shows better AM-AM and AM-PM conversion, and has increased 1 dB compression point by 12.3 dB and $2.0^{\circ}/dB$ phase distortion point by 10 dB. The 3rd order intermodulation distortion, IMD3 is measured to be 37.0 dBc that is 16.2 dB improvement at the operating output. This paper also proposed the measurement method of IMD for high power amplifier, and that TWT amplifier can have better linearity and output power by compensating for the AM-PM characteristics.

• Journal of the Korean Applied Science and Technology
• /
• v.23 no.1
• /
• pp.63-69
• /
• 2006

Methanol and formaldehyde were produced directly by the partial oxidation of methane. The catalysts used were mixed oxides of late-transition metals, such as Mn, Fe, Co, Ni and Cu. The reaction was carried out at $450^{\circ}C$, 50 bar in a fixed-bed differential reactor. The prepared catalysts were characterized by XRD, TPD and BET apparatus. Of the catalysts, A-Mn0.2-6, which contains 0.2 mole of Mn and calcined at $600^{\circ}C$, showed the best catalytic activity: 3.7% methane conversion, and 30 and 28% methanol and formaldehyde selectivities, respectively. The catalytic activity was changed with the content of Mn and the calcination temperature. Catalytic activity increased with the specific surface areas of the catalysts. With XRD, it was found that the structure of the catalysts are changed with calcination temperature. Through $O_2-TPD$ experiment, it was found that the catalysts showing good catalytic activity showed $O_2$ desorption peak around $800^{\circ}C$.

• Korean Journal of Pharmacognosy
• /
• v.26 no.4
• /
• pp.355-359
• /
• 1995

To find serotonin(5-hydroxytryptamine, 5-HT)-antagonizing activities in traditional herbal drugs, crude extracts from 66 kinds of traditional herbal drugs were randomly screened for inhibitory effects on 5-hydroxytryptophan(HTP)-induced diarrhea in mice. Intraperitoneal injection of 5-HTP(2.5 mg/kg) induced diarrhea in 92% of mice, when observed from 10 to 15 min after injection. Crude extracts(2 g/kg) from 66 kinds of traditional herbal drugs were orally pretreated for 1 h before 5-HTP injection. Of the 66 herbal drugs screened, Ephedrae Herba(麻黃), Cimicifugae Rhizoma(升麻), Anisi stellati Fructus(八角茴香), Aurantii Fructus(枳實), Polygalae Radix(遠志) showed the most potent inhibiting activities against 5-HTP(2.5 mg/kg)-induced diarrhea in mice. There are at least 3 possible mechanisms that would be responsible for the inhibitory effect of crude extracts on 5-HTP-induced diarrhea; 1) crude extract-induced inhibition of the activity of aromatic aminoacid decarboxylase catalyzing the conversion of 5-HTP to 5-HT, 2) crude extract-induced blockade of 5-HT receptor(s) in the gastrointestinal tract responsible for 5-HTP-induced diarrhea, 3) crude extract-induced inhibition of gastrointestinal activity, irrespective of 5-HT system. The exact mechanisms and molecules, responsible for the inhibitory effect of crude extracts on 5-HTP-induced diarrhea remain to be clarified.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.3
• /
• pp.400-406
• /
• 2011

An experiment was carried out to assess the effects of xylanase supplementation on the performance, net energy and gut microflora of broilers fed a wheat-based diet. Day-old male broiler chicks were allocated to two dietary treatments. Each treatment was composed of six replicate cages of seven broilers per cage. The diets were wheat-based and offered as mash. The treatments included i) basal diet deficient in metabolizable energy; and ii) basal diet supplemented with a commercial xylanase added at 4,000 U/kg feed. Bird performance, nutrient utilization and gut microbial populations were measured. Heat production and net energy were determined using an auto-control, open circuit respiration calorimetry apparatus. Results showed that exogenous xylanase supplementation improved feed conversion efficiency (p<0.05) and increased diet AME (+4.2%; p<0.05), as well as heat production (HP), net energy for production (NEp), production of $CO_2$, and consumption of $O_2$. The respiratory quotient (RQ) was also increased (p<0.01) by the addition of xylanase. NEp value was increased by 26.1% while daily heat production per kg metabolizable body weight was decreased by 26.2% when the xylanase was added. Xylanase supplementation numerically increased the ileal digestibility of protein and energy by 3 and 6 percentage units respectively (p>0.05). The ileal digestibility of hemicellulose was significantly improved by xylanase addition (p<0.05).

• Korean Journal of Veterinary Research
• /
• v.34 no.2
• /
• pp.275-286
• /
• 1994

Plasma protein which has been known as one of nonspecific immunostimulators was added to feedstuff to examine its effect on the enhancement of cellular immune response in porcine immune system. A total of 40 piglets, 20 male and 20 female each, were fed for 30 days with or without plasma protein. The peripheral blood were collected and analyzed for the investigation of leukocyte subpopulations and their activities by using a panel of monoclonal antibodies specific to porcine leukocyte differentiation antigens and flow cytometry. The results obtained as follows. 1. Total weight gain, daily feed intake and feed conversion rate for 10 days were significantly improved to 56%, 20% and 22% in the piglets fed plasma protein, respectively. 2. A significant increase in N (null or non T/non B) cells was also noticed. Leukocyte proportion from piglets fed plasma protein was 20.2-24.7%, otherwise that from piglets fed without plasma protein was 12.3-13.4%, respectively. 3. A significant increase in the proportion of B cells and cells expressing poCD1 was not found in piglets fed plasma protein. 4. Reaction with monoclonal antibodies specific to adhesion molecules, poCD11a, poCD11b, poCD44 and poCD45A and poCD45B, has shown that leukocyte subpopulation from piglets fed plasma protein did not significantly higher than that from piglets fed without plasma protein. 5. Total proportion of granulocytes and monocytes was about 50% in both group and the proportion after treated with Hypaque/Ficoll was 2.7% and 5.8% in each group, respectively.

• Journal of Hydrogen and New Energy
• /
• v.15 no.4
• /
• pp.274-282
• /
• 2004

This study focused on the development of high performance catalyst for autothermal reforming (ATR) of gasoline to produce hydrogen. The ATR was carried out over MgO/Al2O3 supported metal catalysts prepared under various experimental conditions. The catalysts before and after reaction were characterized by N2-physisorption, CO-chemisorption, SEM and XRD. The performance of supported multi-metal catalysts were better than that of supported mono-metal catalysts. Especially, it was observed that the conversion of iso-octane over prepared Ni/Fe/MgO/Al2O3 catalyst was 99.9 % comparable with commercial catalyst (ICI) and the selectivity of hydrogen over the prepared catalyst was 65% higher than ICI catalyst. Furthermore, it was identified that the sulfur tolerance of prepared catalyst was much better than ICI catalyst based on the ATR reaction of iso-octane containing sulfur of 100 ppm. Therefore, Ni/Fe/MgO/Al2O3 catalyst can be applied for a fuel reformer, hydrogen station and on-board reformer in furl cell powered vehicles.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.8
• /
• pp.614-619
• /
• 2013

Recently, remote phosphor is reported for white LED enhancing of phosphor efficiency compared with conventional phosphor-based W-LED. In this study, Remote phosphor was produced by screen printing coating on glass substrate with phosphor contents rated paste and heat treatment. The paste consists of phosphor, lowest softening glass frit and organic binders. Remote phosphor can be well controlled by varying the phosphor content rated paste. After mounting remote phosphor on top of blue LED chip, CCT, CRI, and luminance efficiency were measured. The measurement results showed that CCT, CRI, and luminance efficiency were 6,645, 68, and 1,16l m/W in phosphor 80 wt.% remote phosphor sintered at $600^{\circ}C$.

• Restorative Dentistry and Endodontics
• /
• v.31 no.6
• /
• pp.415-426
• /
• 2006

In this study, the changes in the degree of conversion (DC) and the microtensile bond strength (MTBS) of self-etching adhesives to dentin was investigated according to the time after curing. The MTBS of Single Bond (SB, 3M ESPE, USA), Clearfil SE Bond (SE, Kuraray, Japan), Xeno-III (XIII, Dentsply, Germany), and Adper Prompt (AP, 3M ESPE, USA) were measured at 48h, at 1 week and after thermocycling for 5,000 cycles between 5$^{\circ}$C and 55$^{\circ}$C. The DC of the adhesives were measured immediately, at 48h and at 7 days after curing using a Fourier Transform Infra-red Spectrometer. The fractured surfaces were also evaluated with scanning electron microscope. The MTBS and DC were significantly increased with time and there was an interaction between the variables of time and material (MTBS, 2-way ANOVA, p = 0.018; DC, Repeated Measures ANOVA, p < 0.001). The low DC was suggested as a cause of the low MTBS of self-etching adhesives, XIII and AP, but the increase in the MTBS of SE and AP after 48h could not be related with the changes in the DC. The microscopic maturation of the adhesive layer might be considered as the cause of increasing bond strength.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2002.11a
• /
• pp.171-184
• /
• 2002

Approx. 200,000 bpd vacuum residue oil is produced from oil refineries in Korea. These are supplying to use asphalt, high sulfur fuel oil, and upgrading at the residue hydro-desulfurization unit. Vacuum residue oil has high energy content, however high sulfur content and high concentration of heavy metals represent improper low grade fuel. To meet growing demand for effective utilization of vacuum residue oil from refineries, recently some of the oil refinery industries in Korea, such as SK oil refinery and LG Caltex refinery, have already proceeded feasibility study to construct 435-500 MWe IGCC power plant and hydrogen production facilities. Recently, KIER(Korea Institute of Energy Research) are studing on the Vacuum Residue gasification process using an oxygen-blown entrained-flow gasifier. The experiment runs were evaluated under the reaction temperature : 1,100~1,25$0^{\circ}C$, reaction pressure : 1~6kg/$\textrm{cm}^2$G, oxygen/V.R ratio : 0.8~0.9 and steam/V.R ratio : 0.4-0.5. Experimental results show the syngas composition(CO+H$_2$) : 85~93%, syngas flow rate : 50~110Mm$^3$/hr, heating value : 2,300~3,000 ㎉/Nm$^3$, carbon conversion : 65~92, cold gas efficiency : 60~70%. Also equilibrium modeling was used to predict the vacuum residue gasification process and the predicted values were compared reasonably well with experimental data.