• Journal of the Korean Electrochemical Society
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• v.10 no.1
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• pp.25-30
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• 2007

Proton exchange membrane fuel cell(PEMFC) performance could be affected by various factors such as cell temperature, total pressure, partial pressure of reactants and relative humidity. Hydrogen ion is combined with water to form hydronium ion [$H_3O^+$] and pass through membrane resulting electricity generation. Cooling system is needed to remove heat and other uses on large scale fuel cell. In case that collant conductivity is increased, fuel cell performance could be decreased because produced electricity could be leaked through coolant. In this study, triple distilled water(TDW) and antifreeze solution containing ethylene glycol was used to observe resistance change. Resistance of TDW was taken 28 days to reach preset value, and effect on fuel cell operation was not observed. Resistance of antifreeze solution was not reached to preset value up to 48 days, but performance failure occurred presumably caused by bipolar plate junction resulting stoppage resistance experiment. Generally PEMFC humidification is performed near-saturated operating conditions at various temperatures and pressures, but non-humidifying condition could be applied in small scale fuel cell to improve efficiency and reduce system cost. However, it was difficult to operate large scale fuel cell without humidifying, especially higher than $50{\sim}60^{\circ}C$. In case of small flux such as 0.78 L/min, temperature difference between inlet and outlet was occurred larger than other cases resulting performance decrease. Non-humidifying performance experiments were done at various cell temperature. When both of anode and cathode humidification were removed, cell performance was strongly depended on cell operating temperature.

• Journal of Life Science
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• v.25 no.3
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• pp.307-316
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• 2015

Beetle larvae have been used as a traditional medicine to treat various human liver diseases. To prove the liver protective function of Allomyrina dichotoma larvae (ADL), we induced liver damage by the intraperitoneal injection of a hepatotoxic reagent, diethylnitrosamine (DEN), to C3H/HeN male mice and orally administered freeze-dried ADL powder. ADL powder lessened DEN-induced hepatotoxicity considering the reduced signs of acute and chronic hepatotoxicities, such as the ALP level in the blood serum, TUNEL-positive hepatocytes, ductural reactions, steatotic hepatocytes, and collagen deposition of the Masson’s trichrome staining. In addition to hepatoprotection, the anti-cancer activity of ADL has been examined. The ADL powder was extracted with ethanol and then fractionated with hexane, ethyl acetate, and water by a solvent partition technique. The ethyl acetate fraction showed cytotoxicity to various cancer cells through induction of apoptosis and necrosis, as well as the perturbed metabolism of the cancer cell to trigger autophagy. Collectively, ADL contains bioactive substances that can protect hepatocytes from toxic chemicals and trigger cell death in cancer cells. Thus, further purification and analyses of ADL fractions could lead to the identification of novel bioactive compounds.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.341-347
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• 2008

The feasibility of commercializing the hydrothermal synthesis of Na-A type zeolite from siliceous mudstone has been conducted using a 50-liter bench-scale autoclave and the application of the zeolite as an environmental remediation agent. Siliceous mudstone, which is widely distributed around the Pohang area, was adopted as a precursor. The siliceous mudstone is favorable for the synthesis of zeolite because it contains 70.7% $SiO_2$ and 10.0% $Al_2O_3$, which are major ingredient of zeolite formation. The synthesis of zeolite was carried out under the following conditions that had been obtained from the previous laboratory-scale tests: 10hr reaction time, $80^{\circ}C$ reaction temperature, $Na_2O/SiO_2$ ratio = 0.6, $SiO_2/Al_2O_3$ ratio = 2.0 and $H_2O/Na_2O$ ratio= 98.6. The crystallinity and morphology of the zeolite formed were similar to those obtained from the laboratory-scale tests. The recovery and cation exchange ion capacity were 95% and 215 cmol/kg, respectively, which are slightly higher than those obtained in laboratory scale tests. To examine the feasibility of the zeolite as an environmental remediation agent, experiments for heavy metal adsorption to zeolite were conducted. Its removal efficiencies of heavy metals in simulated waste solutions decreased in the following sequences: Pb > Cd > Cu = Zn > Mn. In a solution of 1500 mg/L total impurity metals, the removal efficiencies for these impurity metals were near completion (> 99%) except for Mn whose efficiency was 98%. Therefore, the synthetic Na-A type zeolite was proven to be a strong absorbent effective for removing heavy metals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.2
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• pp.154-161
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• 2008

Phellinus linteus (PL) has been known to exhibit potent biological activity. The present study was designed to investigate lipase-inhibitory and anti-oxidative activity of the methanol extract and the powder of PL fruiting body. The methanol extract of PL appeared to have the inhibitory activity against pancreatic lipase with an $IC_{50}$ value of $36.3\;{\mu}g/mL$, and the scavenging activity of DPPH radical with an $IC_{50}$ value of $20.1\;{\mu}g/mL$, which was similar to that of vitamin C ($IC_{50}\;18.3\;{\mu}g/mL$). To investigate the lipase-inhibitory and anti-oxidative effect of PL on animal, Sprague-Dawley rats were fed with high-fat diet supplemented with either 2% or 5% PL powder for 8 weeks. Total food intake was significantly increased, but body weight was not changed by PL powder supplementation. However, fecal fat excretion of the experimental groups fed with the PL powder were higher than that of the control group. PL powder showed a decrease in the plasma total cholesterol, LDL-cholesterol, and the hepatic total cholesterol levels. The anti-oxidative enzyme activities were also affected by PL supplementation. Glutathione peroxidase (GSH-Px) in the plasma and liver were significantly increased by 98% and 46% in the 2% PL group, and 99% and 32% in the 5% PL group, respectively. Total superoxide dismutase (T-SOD) activity was not affected by PL supplementation. DNA damage was measured by the comet assay in the lymphocytes collected after 2 weeks, 4 weeks, and 8 weeks of feeding PL supplemented diet. Lymphocyte DNA damage was decreased in the PL supplemented group. Furthermore, PL feeding enhanced the resistance to lymphocyte DNA damage caused by an oxidant challenge with $H_2O_2$.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1667-1678
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• 1999

Certain parts of 190 kinds of medicinal herbs and 171 kinds of original materials of food were extracted by methanol. The extracts were tested their microbial inhibition activities against several food spoilage microorganisms, Micrococcus luteus, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli, Saccharomyces cerevisiae, Candida albicans, Penicillium citrinum, Aspergillus flavus and Aspergillus niger. The methanol extracts of Cornus officinalis, Evodia officinalis, Glycyrrhiza glabra, Salvia miltiorrhiza. Schizandrae fructus, Coptidis rhizoma, aroma hop and bitter hop were shown inhibitory effect on certain species of gram(+) bacteria. Aroma hop and bitter hop were shown inhibitory effect on certain species of gram(-) bacteria. The methanol extract of Salvia miltiorrhiza exhibited a strong antibacterial activities. It was purified by solvent fractionation, silicagel column chromatography, prep. TLC, prep. HPLC. The purified active substance was identified as cryptotanshinone by EIMS, $1^H-NMR,\;{13}^C-NMR$ and DEPT. Cryptotanshinone showed a strong antibacterial activity against gram positive bacteria $(MIC\;:\;3.91{\sim}62.50\;{\mu}g/mL)$. Especially, this compound was the most strong activity against Bacillus subtilis $(MIC\;:\;3.91\;{\mu}g/mL)$.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.355-363
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• 1982

In order to develop the commercial storage method of potatoes by irradiation combined with natural low temperature, storage room($450{\times}650{\times}250cm$; year round temperature change, $2-17^{\circ}C;\;70-85%\;R.H.$) on a batch scale followed by irradiation with optimum dose level. Irish cobbler and Shimabara were 100% sprouted after 3 months storage in control, whereas in 15 Krad irradiated group, sprouting was completely inhibited at Irish cobbler for 9 months storage, and at Shimabara for 12 months. The extent of loss due to rot attack after 9 months storage was 6% in control, 6-8% in 10-15 Krad irradiated group at Irish cobbler and weight loss was 16.5% in control, 5.1-5.6% in irradiated group, whereas rotting rate of Shimabara after 12 months storage was 100% in control, 15% in irradiated group and the weight loss of its was 12.6% in control, $7.3{\sim}7.4%$ in irradiated group. The moisture content in whole storage period of two varieties were $72{\sim}82%$ without remarkable changes. The total sugar and ascorbic acid contents were slightly decreased according to the dose increase and elapse of storage period, whereas reducing sugar content was increased. Irish cobbler was 90% marketable after 9 months storage and 85% in Shimabara after 12 months storage.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.1-9
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• 2008

The main purpose of this study is to accumulate the fundamental data representing groundwater of plastic film houses by means of water quality and its multivariate statistical analysis. Groundwater samples were collected in every two years since 2000 to 2004 from total 211 sites. According to the result of water quality analysis, ground water quality was suitable for irrigation purpose averagely. Correlation analysis showed that EC was highest positively correlated with $Mg^{2+}$ to 0.810(p<0.01), 0.776(p<0.01) in April and July, respectively. $NO_3-N$ was highest positively correlated with T-N to 0.794(p<0.01) in October. This result shows that it can lead to a different result even in similar case sometimes. Four factors were extracted through factor analysis in April and July, but five factors were extracted in October. The proportions of cumulative variance by the factor were 64.9, 60.2, and 70.7 in April, July, and October, respectively. The first factor was highly related to anions and cations such as $Ca^{2+},\;Mg^{2+},\;Cl^-,\;{SO_4}^{2-}$, and EC in contrast to that of stream water. According to the cluster analysis, 211 sites are classified into four groups. Common type of ground water quality was shown in group A. The pH and $PO_4-P$ were highest in Group B. The anions and cations were highest in Group C. $COD_{Cr}$ was highest in Group D.

• Ultrasonography
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• v.32 no.1
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• pp.59-65
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• 2013

Purpose: The purpose of this study is to establish the methodology regarding synthesis of ultrasound contrast agent imaging, and to evaluate the characteristics of the synthesized ultrasound contrast agents, including size or degradation interval and image quality. Materials and Methods: The ultrasound contrast agent, composed of liposome and SF6, was synthesized from the mixture solution of $21{\mu}mol$ DPPC (1, 2-Dihexadecanoyl-sn-glycero-3-phosphocholine, $C_{40}H_{80}NO_8P$), $9{\mu}mol$ cholesterol, $1.9{\mu}mol$ of DCP (Dihexadecylphosphate, $[CH_3(CH_2)_{15}O]_2P(O)OH$), and chloroform. After evaporation in a warm water bath and drying during a period of 12-24 hours, the contrast agent was synthesized by the sonication process by addition of buffer and SF6 gas. The size of the contrast agent was controlled by use of either extruder or sonication methods. After synthesis of contrast agents, analysis of the size distribution of the bubbles was performed using dynamic light scattering measurement methods. The degradation curve was also evaluated by changes in the number of contrast agents via light microscopy immediate, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, and 84 hours after synthesis. For evaluation of the role as an US contrast agent, the echogenicity of the synthesized microbubble was compared with commercially available microbubbles (SonoVue, Bracco, Milan, Italy) using a clinical ultrasound machine and phantom. Results: The contrast agents were synthesized successfully using an evaporation-drying-sonication method. The majority of bubbles showed a mean size of 154.2 nanometers, and they showed marked degradation 24 hours after synthesis. ANOVA test revealed a significant difference among SonoVue, synthesized contrast agent, and saline (p < 0.001). Although no significant difference was observed between SonoVue and the synthesized contrast agent, difference in echogenicity was observed between synthesized contrast agent and saline (p < 0.01). Conclusion: We could synthesize ultrasound contrast agents using an evaporation-drying-sonication method. On the basis of these results, many prospective types of research, such as anticancer drug delivery, gene delivery, including siRNA or microRNA, targeted molecular imaging, and targeted therapy can be performed.

• Journal of agriculture & life science
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• v.45 no.5
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• pp.81-89
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• 2011

This study was carried out to investigate changes in physicochemical and sensory properties of cooked sausages replaced sodium chloride (NaCl) to potassium chloride (KCl) or magnesium chloride ($MgCl_2$) during storage for 30 days under $4^{\circ}C$. All sausages were prepared with different combination of salts as follow; CTL (1.5% NaCl), KCL (0.9% NaCl+0.6% KCl), MCL (0.9% NaCl+0.6% $MgCl_2$), KML (0.9% NaCl+0.3% KCl+0.3% $MgCl_2$) and PST (1.5% PanSalt). Among sausages moisture content in KML was the highest (p<0.05). Lightness and redness in CTL were lower than those of other treatments, but MCL and KML containing $MgCl_2$ showed higher CIE $L^*$ and $a^*$ values than CTL. The pH in CTL was the highest during storage, however, no significant difference was determined between two treatments, MCL and KML (p>0.05). Crude fat content and water holding capacity (WHC), hardness and cohesiveness of MCL sausages were higher than those of CTL. In sensory characteristics of cooked sausages, saltness in MCL was the lowest during 10 and 20 days of storage (p<0.05). Yellowness in PST was lower than other treatmeants. Gumminess and chewiness of texture property of sausages from MCL and KML were higher than CTL. The results indicate that the replacement of NaCl by KCl improved texture, but meat color was not improved as expected. In contrast, the replacement of NaCl by $MgCl_2$ enhanced color, texture and WHC, whereas partial replacement of NaCl by $MgCl_2$ must reduce bitter taste as compared to sausages manufactured with a NaCl only. Therefore, $MgCl_2$ may be a salt replacing NaCl in cooked pork sausages.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.97-104
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• 2019

This experiment was conducted to investigate the effect of whole crop rice (WCR) based TMR on growth performance and carcass characteristics of Hanwoo steers. WCR "Yeongwoo"was harvested at yellow ripen stage and ensiled for 60 days. The crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), in vitro dry matter digestibility (IVDMD) and total digestible nutrient (TDN) content was 8.4 %, 28.0 %, 53.8 %, 72.4 % and 66.8 %, respectively. For silage quality, pH was 4.37 and lactic and butyric acid content were 2.84 and 0.04 % in DM. Sixteen Hanwoo steers (8-mon-old) were allocated into either a control (commercial TMR) and WCR-TMR (WCR-based TMR) group. The TMR were fed according to the feeding stage phase: growing (Initiate~14 month), early fattening (15 month~21 month) and late fattening (22 month~30 month). The body weight of control group increased (P<0.05) until early fattening stage, but late growing stage of WCR-TMR group was higher than that of control (P<0.05). Average daily gain (ADG) was significantly greater (P<0.05) in WCR-TMR group (total 0.78 kg/head) compared to control (total 0.66 kg/head) except for late fattening stage. The marketing weight and carcass weight were higher in WCR-TMR group (726 vs 765 kg; 417.8 vs 450.4 kg). The back fat thickness (11.75 vs 13.00 mm), Longissimus dorsi area (88.00 vs $89.88cm^2$) and yield index (65.87 vs 64.30) were not different between the two groups (P>0.05) and also no difference in meat yield grade (A : B : C = 2 : 4 : 2). Marbling score (4.00 vs 4.13), meat color (4.75 vs 4.75), fat color (3.13 vs 2.88), texture (1.25 vs 1.50) and maturity (2.00 vs 2.00) were not significant difference between the two groups and meat quality grade ($1^{{+}{+}}:1^+:1:2:3=0:2:4:2:0$) was also not different. In conclusion, TMR feeding based on WCR silage showed superiority in carcass yield and ADG compared to control TMR. It is considered that the use of WCR for feed is a necessary option for the substitution of the imported forages and the government's policy for rice production adjustment.