• Journal of Electrochemical Science and Technology
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• 제5권2호
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• pp.58-64
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• 2014

The surface of an ordered mesoporous silica (OMS) was functionalized using 1H,1H,2H,2H-perfluorooctyltrimethoxysilane at $20^{\circ}C$ and $60^{\circ}C$. It was shown that only elevated temperature allows lyophobic properties on the walls of OMS, eventually preventing pore flooding with nonaqueous electrolytes. The functionalized OMSs (OMS-F) were characterized with various techniques: wettability test, $N_2$ sorption measurement, high-resolution transmission electron microscopy (HR-TEM). Cathodes of $10mg/cm^2$ loading were prepared with a commercial Pt/C catalyst and polyvinylidene fluoride (PVDF, 2.5 wt.%) binder using a typical doctor blade method on a commercial gas diffusion layer (GDL) in the presence or in the absence of OMS-F additives. Subsequent discharge-charge curves were taken in a 1M LiTFSI-TEGDME electrolyte at 60oC in pure oxygen atmosphere. It was found that the discharge capacity was significantly affected by OMS-F: 5 wt.% of additive extended discharge capacity by a factor 1.5. On the other hand, a similar OMS material but synthesized at $20^{\circ}C$ did not show lyophobic properties and deteriorated cathode capacity.

• Advances in Traditional Medicine
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• 제9권4호
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• pp.277-284
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• 2009

The methanol extract of Dillenia indica was tested for antioxidant activity as determined by free radical scavenging of DPPH radical scavenging assay, reducing power, total antioxidant capacity measured by phosphomolybdenum method, total phenolic content and total flavonoids content determination assays. The extract showed significant activities in all antioxidant assays compared to the standard antioxidant in a dose dependent manner. In DPPH radical scavenging assay the $IC_{50}$ value of the extract was found to be 100.53${\mu}g/ml$ while ascorbic acid has the $IC_{50}$ value 58.92${\mu}g/ml$. Dillenia indica extract showed strong reducing power and total antioxidant capacity. Moreover, methanol extracts also possess high amount of phenolics and flavovonoids and expressed as gallic acid and rutin equivalent respectively. The remarkable activities exhibited in reactive oxygen species scavenging may attributed to the high amount of hydrophilic phenolics present in Dillenia indica.

• 한국약용작물학회지
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• 제24권5호
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• pp.351-359
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• 2016

Background: We investigated the optimal aqueous extraction conditions for recovery of high yields of total phenolic compounds from roots of Arctium lappa L. (burdock, Asteraceae), and we compared their antioxidant capacity. Methods and Results: The antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt, and oxygen radical absorbance capacity assays. In addition, the major phenolic compounds present in the extracts were determined by high performance liquid chromatography analysis. Our results suggest that the roasted burdock $100^{\circ}C$, 15 min extract exhibited the strongest radical scavenging activity and possessed the highest concentration of phenolic compounds. The polyphenol content of both dried burdock and roasted burdock significantly increased with increase in the extraction temperature and time. Conclusions: These results indicated a relationship between phenolic compound levels in burdock and their free radical scavenging activities. This suggests that phenolic compounds significantly increase the antioxidant potential of burdock extracts.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1505-1510
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• 2009

Arginyl-fructose (AF) and arginyl-fructosyl-glucose (AFG) were chemically synthesized and purified. Their in vitro and cellular antioxidant activity was investigated using oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity assay, respectively. The peroxyl radical scavenging activity of AF was much higher than that of AFG, which was in good agreement with their reduction capacity to donate electrons or hydrogen atoms. On the other hand, the hydroxyl radical scavenging activity of AF was weaker than that of AFG, which was consistent with their metal chelating activity, suggesting that AFG-$Cu^{2+}$ complex may be less redox-active than AF-$Cu^{2+}$ complex due to 1 glucose molecule attached. The cellular antioxidant activity of AF and AFG appeared to depend on both their permeability into cell membrane and the scavenging activity on peroxyl or hydroxyl radicals. These results indicate that AF and AFG, Maillard reaction products, may have a high potential as a material for the development of nutraceutical food with antioxidant activity.

• 한국수소및신에너지학회논문집
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• 제32권1호
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• pp.53-62
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• 2021

Batch type reduction-oxidation tests were performed to check effects of temperature, pressure, gas velocity, and capacity on reduction characteristics of mass produced particle in a 0.5 MWth chemical looping combustion system. The fuel conversion and the CO2 selectivity increased as the temperature increased and as the gas velocity decreased. However the CO2 selectivity showed the maximum and decreased as the capacity increased because the CO emission increased. The results show that high temperature, low gas velocity and low inert gas concentration are preferable to ensure high reactivity of oxygen carrier in the fuel reactor.

• 순환기질환의공학회:학술대회논문집
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• 순환기질환의공학회 2005년도 제5회 학술대회 초록집
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• pp.21-22
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• 2005

• 한국수소및신에너지학회논문집
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• 제15권3호
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• pp.208-219
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• 2004

To find a suitable oxygen carrier particle for a 50kW chemical-looping combustor, which was designed and installed to demonstrate continuous oxidation and reduction, three oxygen carrier particles(NiO/bentonite, $NiO/NiAl_2O_4$, $CoO_x/CoAl_2O_4$) were prepared. The reactivity and the attrition resistance of particles were measured and investigated by a thermo-gravimetrical analyzer and an attrition test apparatus respectively. From the viewpoints of oxygen transfer capacity, optimum reaction temperature(operating temperature range), reaction rate, carbon deposition rate, and attrition resistance, NiO/bentonite particle showed better performance than the other particles, therefore we selected NiO/bentonite particle as an optimum oxygen carrier particle.

• 한국수소및신에너지학회논문집
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• 제27권1호
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• pp.95-105
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• 2016

Spray-dried NiO-based oxygen carriers developed for chemical looping combustion required high calcination temperatures above $1300^{\circ}C$ to obtain high mechanical strength applicable to circulating fluidized-bed process. In this study, the effect of CBB ($CaO{\cdot}BaO{\cdot}B_2O_3$) addition, as a binder, on the physical properties and oxygen transfer reactivity of spray-dried NiO-based oxygen carriers was investigated. CBB addition resulted in several positive effects such as reduction of calcination temperature and increase in oxygen transfer capacity and porosity. However, oxygen transfer rate was considerably decreased. This was more apparent when a higher amount of CBB was added and MgO was added together. From the experimental results, it is concluded that CBB added NiO-based oxygen carriers are not suitable for chemical looping combustion and a new method to reduce calcination temperature while maintaining high oxygen transfer rate of NiO-based oxygen carriers should be found out.

• 여성건강간호학회지
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• 제6권4호
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• pp.594-605
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• 2000

The purpose of this study is to collect fundamental data for adult female health improvement based on urban adult female obesity and cardiopulmonary function. Surveyed were 859 adult females who visited a health improvement center in D district in Seoul between April, 1999, and December, 1999, and the resulting data are as follows: 1. The adult female mean BMI was $23.97{\pm}3.11kgm^2$, which comes within the range of overweight. Among them, BMI of the females aged 41-60, and over 60, were significantly higher. Mean percentage of body fat was $32.07{\pm}4.63$, and it significantly increased in accordance with age, recording the highest among those aged over 60. 2. The systolic blood pressure significantly increased in accordance with age, recording highest among those aged over 60. Those aged 41-60 and over 60 showed significantly higher diastolic blood pressure than those in their 20s and 30s; however, they had a significantly lower heart rate. Vital capacity and maximum oxygen intake significantly decreased in accordance with age, and those aged over 60 were lowest. 3. As to health perception, 20.6% of the subjects perceived themselves as healthy, and those who perceived themselves as unhealthy showed significantly higher BMI than those who perceived themselves to be of moderate health. 4. There were no significant differences in blood pressure, heart rate and maximum oxygen intake in accordance with health perception, but those who perceived themselves as healthy showed significantly higher vital capacity than those who didn't. 5. As to cardiopulmonary function in accordance with obesity, the obese group showed significantly higher systolic blood pressure than those whose weight was normal to overweight. The diastolic blood pressure of the normal weight group was the lowest, while the obese group showed significantly lower vital capacity and maximum oxygen intake. These findings indicate that the womens' health promotion program must include an effective strategy for preventing obesity, and strengthening cardiopulmonary function.

• 대한의생명과학회지
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• 제19권1호
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• pp.70-78
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• 2013

This study was conducted to identify the effects of intake of beta-blocker and aerobic exercise on heart rate recovery (HRR) and exercise capacity after maximal exercise in acute coronary syndrome patients (ACS). Subjects were divided into 4 groups; Beta-blocker-Exercise group (n=10), Beta-blocker group (n=10), Exercise group (n=10), Control group (n=10). Symptom-limited grade exercise test were conducted on subjects pre- and post- 6 week study, to measure maximal heart rate, heart rate at 1 minute and 2 minutes at the recovery stage, maximal oxygen uptake and maximal exercise time. Study resulted in significant improvements in heart rate recovery for BB-Ex group ($17.40{\pm}5.58$ bpm to $26.10{\pm}6.66$ bpm), maximal oxygen uptake for BB-Ex group ($30.46{\pm}8.63$ to $36.33{\pm}8.10$) and Ex group ($29.04{\pm}4.93$ to $34.31{\pm}5.19$), and total exercise time for BB-Ex group ($906.30{\pm}158.57$ to $1018.50{\pm}151.21$), BB group ($805.70{\pm}182.94$ to $897.50{\pm}160.16$) and Ex group ($870.00{\pm}145.63$ to $961.90{\pm}107.29$). Therefore it showed the biggest improvement for heart rate recovery and exercise capacity in acute coronary syndrome patients when both Beta-blocker and aerobic exercise were in effect.