• 멤브레인
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• 제29권5호
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• pp.252-262
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• 2019

서로 다른 술폰화 정도에 따라 sulfonated star branched poly(styrene-b-butadiene-b-styrene) triblock copolymer (SSBS)가 합성되었다. 술폰화된 butadiene block은 FT-IR spectroscopy로 확인할 수 있다. 술폰화 정도를 측정 비교하기 위해서 산-염기 적정을 통하여, ion exchange capacity (IEC)를 계산하였다. 술폰화된 SSEB 전해질막은 높은 water uptake와 proton conductivity를 보였다. 실온에서 25 mol% 술폰화된 SSBS는 0.114 S/cm라는 높은 값을 나타냈으며, 이는 Nafion과 비슷한 수치였다. 일정한 상대 습도에서 온도의 증가는 현저하게 높은 수소이온전도도를 나타냄을 알 수 있었다. 모든 술폰화된 막은 Nafion과 비교했을 때 낮은 methanol 투과도를 보여주었다. AFM을 이용하여 술폰화된 전해질막의 구조는 이른바 분리된 나노구조의 미세상과 ionic channel의 접속으로 이루어졌음을 확인할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2657-2662
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• 2013

Multiwalled carbon nanotube (MWCNT)-g-poly (aniline-co-2,5-diaminobenzenesulfonic acid) (DABSA) reinforced Nafion$^{(R)}$ nanocomposite membranes were prepared and characterized for direct methanol fuel cells (DMFCs). The nanocomposite membranes with approximately $90{\mu}m$ thickness were prepared by the water assisted solution casting method. To evaluate the properties of nanocomposite membranes for DMFC applications, the nanocomposite membranes were characterized by methanol and water uptake, thermal stability, and ion exchange capacity (IEC). Furthermore, oxidative stability measurements in terms of the hydrogen peroxide decomposition rate that represent the oxidative stability of the membranes were examined. The methanol uptake values of the nanocomposite membranes were dramatically decreased compared to the cast Nafion$^{(R)}$ membranes. The IEC values of the nanocomposite membranes were increased about 30% compared to the cast Nafion$^{(R)}$ membrane.

• Journal of Nutrition and Health
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• 제28권9호
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• pp.904-913
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• 1995

The purpose of this study is to determine the effects of exercise programs on the treatment of chronic diseases. For this purpose, nine middle-aged women suffering from such chronic diseases as obesity, hypertension and coronary heart disease(CHD) were sampled to perform a 4-month-long exercise program which required the lactate threshold(LT) level corresponding to 70% of maximal oxygen uptake(VO2max). Thereupon, their physiques, physical fitness, blood components and physiological varibles were compared pre and post of exercise program. The results were summarized as follows ; 1) After the 4-month-long exercise program, %fat was significantly decreased, while such variables as grip strength, side step, trunk flexion and leg balance were significantly increased. 2) Blood components such as TG, TC, HDL-C, LDL-C, hemoglobin and hematocrit did not show and change in after exercise program. 3) Physiological varables such as HR, SBP, DBP, HR/LT, SBP/LT, DBP/LT, RPE/LT, VE/LT, VO2/LT and VO2 max showed significant increase after 4-month exercise program. These results suggest that regular aerobic exercise in a long period might help to decrease % fat and to increase aerobic capacity in middle-aged women suffering from chronic diseases.

• 복합신소재구조학회 논문집
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• 제6권3호
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• pp.8-13
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• 2015

This study investigates the application of a synthetic resine based net-hose system to sustain vegetated embankment slope reinforcement. The net-hose system is designated to improve water supply to the vegetation that can suffer the lack of water in case of extreme drying condition or rock slope where water supply is relatively insufficient to ensure the growth of vegetation. A series of laboratory tests were conducted to check the structural adequacy and effectiveness of net-hose system. The results indicated that the model slope equipped with net-hose system seemed to provide better water supply resulting in more vegetated areas and higher matric suction due to active water uptake capacity, which might be contributed to greater shear strength of slope surface. A limited numerical analysis was conducted to verify the effect of water uptake on vegetated root system that generally yields better slope stability.

• Environmental Engineering Research
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• 제22권4호
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• pp.401-406
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• 2017

Ammonia, $NH_3$, is a key chemical widely used in chemical industries and a toxic pollutant that impacts human health. Thus, there is a need for the development of effective adsorbents with high uptake capacities to adsorb $NH_3$. An adsorbent with a high surface area and a small pore size is generally preferred in order to have a high capacity for the removal of $NH_3$. The use inorganic nanoporous materials as gas adsorbents has increased substantially and emerged as an alternative to zeolite and activated carbon. Herein, mesoporous alumina (MA) was prepared and used as an $NH_3$ adsorbent. MA showed good pore properties such as a uniform pore size and interlinked pore system, when compared to commercial adsorbents (activated carbon, zeolite, and silica powder). MA has free hydroxyl groups, serving as useful adsorption sites for $NH_3$. In an adsorption isotherm test, MA exhibited 4.7-6.5 times higher uptake capacities for $NH_3$ than commercial adsorbents. Although the larger surface areas of adsorbents are important features of ideal adsorbents, a regular and interlinked adsorbent pore system was found to be a more crucial factor to adsorb $NH_3$.

• 한국수산과학회지
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• 제38권3호
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• pp.153-157
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• 2005

The biosorption of Pb and Cr by Sargassum thunbergii was investigated in a batch conditions. The Pb and Cr uptake capacity of Sargassum thunbergii was 232.5 mg Pb/g biomass and 91.6 mg Cr/g biomass, respectively. An adsorption equilibria was reached within about 0.5 hr for both the Pb and the Cr. The adsorption parameters for both the Pb and the Cr were determined according to the Langmuir and Freundlich model. With increasing pH values, more negative sites are becoming available for the adsorption of Pb and Cr. The selectivity of mixture solution showed an uptake order of Pb>Cu>Cr>Cd. Pb and Cr adsorbed by S. thunbergii could be recovered ken 0.1 M HCl, 0.1 M $HNO_3$ and 0.1M EDTA by a desorption process, and the efficiency of Pb desorption was above $95.8\%$, whereas the efficiency of the Cr desorption was below $50.7\%$.

• Advances in concrete construction
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• 제11권5호
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• pp.367-374
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• 2021

The present study investigated the effect of the combined carbonation and steam curing on the physicochemical properties and CO₂ uptake of the Portland cement concrete. Four different curing regimes were adopted during the initial 10 h of curing to evaluate the potential of carbonation curing as an alternative to conventional steam curing in the precast concrete industry from environmental and practical viewpoints. Four combinations of carbonation and steam curing conditions were applied as curing regimes to the samples at an early age. The test results indicated that the samples treated with the combined carbonation and steam curing exhibited higher early strength development compared to the other samples, signifying that carbonation curing can reduce the production time of precast concrete. Furthermore, the CO₂ uptake capacity of the samples was calculated and found to be as high as 18% with respect to the mass of the paste samples. Hence, the simultaneous utilization of steam and CO₂ for the fabrication of precast concrete members has the potential to make precast concrete greener and more cost-effective.

• 한국전문물리치료학회지
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• 제29권3호
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• pp.200-207
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• 2022

Background: The oxygen uptake efficiency slope (OUES) is the most important index for accurately measuring cardiopulmonary function in patients with acute ischemic heart disease. However, the relationship between the OUES variables and important cardiopulmonary function parameters remain unelucidated for patients with acute ischemic heart disease, which accounts for the largest proportion of heart disease. Objects: The present cross sectional clinical study aimed to determine the multiple relationships among the cardiopulmonary function variables mentioned above in adults with acute ischemic heart disease. Methods: A convenience sample of 110 adult inpatients with ischemic heart disease (age: 57.4 ± 11.3 y; 95 males, 15 females) was enrolled at the hospital cardiac rehabilitation center. The correlation between the important cardiopulmonary function indicators including peak oxygen uptake (VO₂ peak), minute ventilation (VE)/carbon dioxide production (VCO₂) slope, heart rate recovery (HRR), and ejection fraction (EF) and OUES was confirmed. Results: This study showed that OUES was highly correlated with VO₂ peak, VE/VCO₂ slope, and HRR parameters. Conclusion: The OUES can be used as an accurate indicator for cardiopulmonary function. There are other factors that influence aerobic capacity besides EF, so there is no correlation with EF. Effective cardiopulmonary rehabilitation programs can be designed based on OUES during submaximal exercise in patients with acute ischemic heart disease.

• 한국식품저장유통학회지
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• 제30권5호
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• pp.797-810
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• 2023

Elaeagnus umbellata leaves have been reported to suppress inflammation, allergic responses, lung cancer proliferation and oral bacterial growth. Cadmium (Cd) is a heavy metal that has been found to cause many toxicities, including liver toxicity. The aim of this study was to evaluate the capacity of 70% ethanol extract of E. umbellata leaves (EUL) to protect human hepatocytes from Cd toxicity. After exposure of HepG2 cells to Cd at 10 𝜇M for 24 h, cell viability, expression levels of apoptosis- and antioxidant-related proteins, reactive oxygen species (ROS) accumulation and Cd uptake were assessed. EUL protected HepG2 cells from Cd-induced apoptosis as determined by MTT assay. A decrease in caspase-3 and p-p53 protein levels was observed in cells pretreated with EUL prior to Cd exposure. Furthermore, the Cd-induced increase in intracellular DCF fluorescence was attenuated by EUL, indicating that the Cd-induced apoptosis preventing effect was associated with the suppression of ROS accumulation. Moreover, EUL's effects on the inhibition of p38, JNK, and AKT phosphorylation also appear to be associated with protection against Cd toxicity. Moreover, EUL upregulated Cd-depressed expression of Nrf2, HO-1, catalase, and MT-1,2 proteins, suggesting that Cd uptake-induced apoptosis in HepG2 cells may be inhibited by EUL's antioxidative potential.

• Mycobiology
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• 제45권2호
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• pp.73-83
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• 2017

The ability of dead cells of endophytic Drechslera hawaiiensis of Morus alba L. grown in heavy metals habitats for bioremoval of cadmium ($Cd^{2+}$), copper ($Cu^{2+}$), and lead ($Pb^{2+}$) in aqueous solution was evaluated under different conditions. Whereas the highest extent of $Cd^{2+}$ and $Cu^{2+}$ removal and uptake occurred at pH 8 as well as $Pb^{2+}$ occurred at neutral pH (6-7) after equilibrium time 10 min. Initial concentration 30 mg/L of $Cd^{+2}$ for 10 min contact time and 50 to 90 mg/L of $Pb^{2+}$ and $Cu^{2+}$ supported the highest biosorption after optimal contact time of 30 min achieved with biomass dose equal to 5 mg of dried died biomass of D. hawaiiensis. The maximum removal of $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$ equal to 100%, 100%, and 99.6% with uptake capacity estimated to be 0.28, 2.33, and 9.63 mg/g from real industrial wastewater, respectively were achieved within 3 hr contact time at pH 7.0, 7.0, and 6.0, respectively by using the dead biomass of D. hawaiiensis compared to 94.7%, 98%, and 99.26% removal with uptake equal to 0.264, 2.3, and 9.58 mg/g of $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$, respectively with the living cells of the strain under the same conditions. The biosorbent was analyzed by Fourier Transformer Infrared Spectroscopy (FT-IR) analysis to identify the various functional groups contributing in the sorption process. From FT-IR spectra analysis, hydroxyl and amides were the major functional groups contributed in biosorption process. It was concluded that endophytic D. hawaiiensis biomass can be used potentially as biosorbent for removing $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$ in aqueous solutions.