• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.1
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• pp.83-91
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• 2001

Purpose: The aim of this study was to investigate the current prevalence of protein-energy malnutrition (PEM) and the nutritional status of hospitalized pediatric patients. Methods: We evaluated the nutritional status of the 200 patients from February to July 1994 and the 233 patients from February to July 1999 admitted to Pediatric Department of Chosun University Hospital. Nutritional status was assessed by anthropometric and laboratory data. The nutritional status was classified according to based on the Waterlow criteria and using the laboratory data obtained between 3 days to 5 days after admission. Results: 1) The prevalence of acute PEM (weight for height) was as follows: severe, 0.5%; moderate, 7%; mild, 18%; and none, 74.5% in 1994 and severe, 2.24%; moderate, 3.59%; mild, 19.73%; and none, 74.4% in 1999. 2) The prevalence of chronic PEM (height for age) was as follows: severe, 5%; moderate, 5.5%; mild, 25.5%; and none, 64% in 1994 and severe, 2.24%; moderate, 4.04%; mild, 22.87%; and none, 70.85% in 1999. There was not a statistically significant difference between 1994 and 1999. 3) The prevalence of PEM according to age group, all age group had in general higher prevalence of mild PEM. 4) Values for hemoglobin and albumin were below than total lymphocyte values in PEM. Conclusion: The prevalence of acute or chronic PEM was common in hospitalized children. Therefore, the assessment of nutritional status may an important role to establish effective nutritional support and to improve their subsequent hospital course in hospitalized pediatric patient.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.113-120
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• 2010

Air-cathode microbial fuel cell consisted of 4 unit cells were operated under batch condition and electricity generation and microbial community structure variation were investigated, depending on separator types and cathode characteristics: A) PEM(Proton Exchange Membrane)-30% Wet proofing Carbon Cloth(WC), B) AEM(Anion Exchange Membrane-WC, C) CEM(Cation Exchange Membrane)-WC, D) PEM-No Wet proofing Carbon Cloth(NC). Maximum power densities of PEM-WC, AEM-WC and CEM-WC were 510.9, 522.1 and 504.8 $mW/m^2$, respectively. But PEM-NC showed relatively lower maximum power density of 218.3 $mW/m^2$. And PEM-WC, AEM-WC and CEM-WC showed similar internal resistances(20.0-28.2 ${\Omega}$). PCRDGGE, PCA and diversity indices showed that uncultured bacteria which reported in previous MFC studies were detected in suspended growth bacteria and attached growth bacteria would be affected not by separator type but by cathode characteristic. Thus, cathode characteristic can be one of the critical factors for power generation in air-cathode MFC using PEM, AEM, and CEM as separator.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1439-1445
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• 2010

In this study, we investigated the inhibition of phyto-extract mixture (PEM) in several digestive enzymes ($\alpha$-amylase, $\alpha$-glucosidase and lipase) for anti-obesity. The current study also examined the effects of PEM on adiposity and serum lipid levels in obese mice fed with high fat diet. ICR male mice weighing $33{\pm}1.1\;g$ were randomly divided into three groups, one normal diet group (control, ND group) and two high fat diet groups with or without PEM supplement (HFD group and PEM group). The mice were fed the PEM experimental for 6 weeks and then they were sacrificed. The results showed that the final weight, weight gain, food efficiency ratio and body fat were decreased by the addition of PEM compared to those of HFD group. White adipose tissue weights of epididymal, mesenteric and retroperitoneal areas in the PEM group were reduced to 31.2%, 8.8%, and 37.8%, respectively, compared to the HFD group. The levels of serum triglyceride, total cholesterol, LDL-cholesterol in the PEM group were significantly lower than those of HFD group. The body weight gain and food efficiency ratio of PEM group were significantly lower compared with those of HFD group. From the above results, the PEM may be effective material for anti-obesity through reducing serum triglyceride and body fats as well as decreasing body weight.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.61-63
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• 2007

본 연구에서는 소형 PEM 연료전지스택을 이용한 휴대용 전원 시스템을 설계하고 그 성능을 시험하였다. 시스템은 30W PEM 연료전지 스택과 제어기, 고압 수소 실린더, DC-DC Converter로 구성되고, 구성된 시스템을 이용하여 10W DVD Player의 구동을 성공적으로 실시하였다. 500cc 350기압의 실린더를 이용할 경우 32시간 이상의 사용이 가능함을 실험을 통해 증명하였다.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.E2
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• pp.85-95
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• 2002

Hydrogen peroxide and methyl hydroperoxide were measured over the northwestern Pacific Ocean during NASA's PEM (Pacific Exploratory Mission) -West. The first experiment (PEM -West A) was conducted in the fall of 1991 and PEM-West B in the early spring of 1994. Hydroperoxide data were obtained on board the NASA DC -8 aircraft through the entire depth of the troposphere. Average concentrations of both H$_2$O$_2$and CH$_3$OOH were higher during PEM -West A than B. The seasonal difference in hydroperoxide distribution was determined by the degree of photochemical activities and the strength and location of jetstream, which led to extensive and rapid continental outflow during the PEM-West B. While for H$_2$O$_2$distribution, a longitudinal gradient was more apparent than a latitudinal gradient, it was opposite for the CH$_3$OOH distribution. The longitudinal gradient indicates the proximity to the anthropogenic sources from the Asian continent, but the latitudinal gradient reflects photochemical activity. During PEM -West B, the ratio of C$_2$H$_2$/CO, a tracer for continental emission was raised and high concentrations of H$_2$O$_2$were associated with high ratios. The flux of hydroperoxide toward the North Pacific was also enhanced in the early spring. The eastward fluxes of H$_2$O$_2$ were 9% and 17% of the average photochemical production over the Pacific Basin between 140°E and 130°W during PEM-West A and B, respectively. For CH$_3$OOH, these ratios were 8% and 13%. Considering the lifetime of hydroperoxide and the rapid transport of pollutants, the export of hydroperoxide with other oxidants would have a significant influence on oxidant cycles over the North Pacific during winter/spring.

• BMB Reports
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• v.35 no.5
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• pp.476-481
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• 2002

The CHH/MIH/GIH peptide family of black tiger prawn (Paneaus monodon) is important in shrimp reproduction and growth enhancement. In this study, the cDNA that encodes the complete peptide that is related to the CHH/MIH/GIH family (so-called, Pem-CMG) in the eyestalk of P. monodon was successfully expressed in a methylotrophic yeast Pichia pastoris under the control of an alcohol oxidase promoter. In order to obtain the secreted Pem-CMG, a secretion signal of either the Saccharomyces cerevisiae $\alpha$-factor or Pem-CMG was employed. The results demonstrated that ${\alpha}Pem$-CMG, either with (${\alpha}2EACMG$) or without (${\alpha}CMG$) the Glu-Ala repeats, was secreted into the medium, while Pem-CMG with its own secretion signal failed to be secreted. The total protein amount that was secreted from the transformant that contained either ${\alpha}2EACMG$ or ${\alpha}CMG$ was approximately 60 mg/l and 150 mg/l, respectively. The N-terminus of the Pem-CMG peptide of both ${\alpha}2EACMG$ and ${\alpha}CMG$ was correctly processed. This produced the mature Pem-CMG peptide.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.326-329
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• 2005

Proton exchange membrane (PEM) should be sufficiently hydrated with proper water management to maintain a good ionic conductivity and performance of a PEM fuel cell. However. cathode flooding resulting from excess water can impede the transport of reactants and hence deteriorate the fuel cell performance. For the PEM fuel cell to be commercially viable as vehicle or portable applications, the flooding on the cathode side should be minimized during the fuel cell operation. In this study, visualization technique was applied to understand the cathode flooding phenomena on the cathode side of a PEM fuel cell. To this end. a transparent PEM unit fuel cell wi th an act ive area of $25cm^2$ was designed and manufactured to allow for the visualization of cathode channel with performance characteristics. Two-phase flow resulting from the electro-chemical reaction of fuel cell was investigated experimentally. The images photographed by CCD camera with cell operating temperatures $(30\~50^{\circ}C)$ were presented. Results indicated that the flooding on the cathode side first occurs near the exit of cathode channel. As the operating temperature of fuel cell increases. it was found that liquid water droplets tend to evaporate easily and it can have an influence on lowering the flooding level. It is expected that this study can effectively contribute to the detailed researches on modeling water transport of an operating PEM fuel cell including two-phase flow phenomena.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.101-104
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• 2006

Water management is considered to be one of the main issues to be addressed for the performance improvement of proton exchange membrane (PEM) fuel cell. For good water management, the detailed information on the water distribution inside an operating PEM fuel cell should be available to main an adequate level of hydration in the PEM While avoiding performance decline due to liquid rater flooding. For the PEM fuel cell to be commercially viable as vehicle applications, the flooding on the cathode side should be minimized during the fuel ceil operation. In this study to investigate cathode flooding and its relation with temperature distribution in flow channels, visualization study was performed on the cathode side of a PEM fuel cell. For the direct visualization of temperature field and water transport in cathode flow channels, a transparent cell was designed and manufactured using quartz window. Water transport and its two-phase flow characteristics in flow channels were investigated experimentally. Also, the visualization of temperature distribution In cathode flow channels was made by using IR camera. Results indicated that the temperature rise near the exit of cathode flow channel was found. It is found that this area corresponds to the flooding area from both temperature and flooding visualization results It is expected that this study can effectively contribute to get the detailed data on water transport linked with heat management during the operation of a PEM fuel cell

• Journal of the Korean Solar Energy Society
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• v.34 no.4
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• pp.9-16
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• 2014

A proton exchange membrane is a core component in the proton exchange membrane fuel cell because the role of proton exchange membrane(PEM)is supplying proton conductivity to fuel cell, a gas separator, and insulating between an anode and cathode. Among various role of PEM, supplying proton conductivity is the most important and the proton conductivity is strongly related the structural evolution of PEM by hydration. Thus a lot of studies have done by past few decade based on small angle X-ray scattering and wide angle X-ray scattering for understanding morphological structure of the PEM. Resulting from these studies, several morphological models of hydrated PEM are proposed. Current sensing atomic force microscopy (CSAFM) can map morphology and conductance on the membrane simultaneously. It can be the best tool for studying heterogenous structured materials such as PEM. In this study, the hydration of the membrane is examined by using CSAFM. Conductance and morphological images are simultaneously mapped under different relative humidity. The conductance images, which are mapped from different relative humidity, are analyzed by statistical methode for understanding ionic channel variation in PEM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.737-738
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• 2007