• Title/Summary/Keyword: O2 plasma

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Lipoprotein(a) Level and Influential Factors in Children with Common Renal Diseases (소아에서 흔한 신장 질환에서 Lp(a)의 양상과 영향을 미치는 인자에 대한 평가)

  • O Chong-Gwon;Lim In-Seok
    • Childhood Kidney Diseases
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    • v.7 no.2
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    • pp.125-132
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    • 2003
  • Purpose : Lipoprotein(a) is a genetically determined risk factor for atherosclerotic vascular disease and is elevated in patients with renal disease. Especially the patients with nephrotic syndrome exhibit excessively high Lp(a) plasma concentrations. Also the patients with end-stage renal disease have elevated Lp(a) levels. But the mechanism underlying this elevation is unclear. Thus, in this study, by measuring the level of serum Lp(a) in common renal diseases in children, we hoped to see whether there would be a change in Lp(a) in renal diseases other than nephrotic syndrome. Then, we figured out its implications, and looked for the factors that affect the Lp(a) concentrations. Methods : A total of 75 patients(34 patients with hematuria of unknown etiology, 10 with hematuria and hypercalciuria, 8 with IgA nephropathy, 8 with poststreptococcal glomerulone phritis, 3 with $Henoch-Sch\"{o}nlein$ nephritis, 7 with urinary tract infection, and 5 with or- thostatic proteinuria) were studied. The control group included 20 patients without renal and liver disease. Serum Lp(a), total protein, and albumin levels, 24-hour urine protein and calcium excretions, creatinine clearance and the number of RBCs and WBCs in the urinary sediment were evaluated. Data analysis was peformed using the Student t-test and a P-value less than 0.05 was considered to be statistically significant. Results : LP(a) was not correlated with 24-hour urine calcium and creatinine. Lp(a) level had a positive correlation with proteinuria and negative correlation with serum albumin and serum protein. Among the common renal diseases in children, Lp(a) was elevated only in orthostatic proteinuria (P<0.05). Conclusion : Lp(a) is correlated with proteinuria, serum protein, and serum albumin, but not with any kind of specific renal disease. Afterward, Lp(a) needs to be assessed in patients with orthostatic proteinuria and its possible role as a prognostic factor could be confirmed.

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Quantitative Elemental Analysis in Soils by using Laser Induced Breakdown Spectroscopy(LIBS) (레이저유도붕괴분광법을 활용한 토양의 정량분석)

  • Zhang, Yong-Seon;Lee, Gye-Jun;Lee, Jeong-Tae;Hwang, Seon-Woong;Jin, Yong-Ik;Park, Chan-Won;Moon, Yong-Hee
    • Korean Journal of Soil Science and Fertilizer
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    • v.42 no.5
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    • pp.399-407
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    • 2009
  • Laser induced breakdown spectroscopy(LIBS) is an simple analysis method for directly quantifying many kinds of soil micro-elements on site using a small size of laser without pre-treatment at any property of materials(solid, liquid and gas). The purpose of this study were to find an optimum condition of the LIBS measurement including wavelengths for quantifying soil elements, to relate spectral properties to the concentration of soil elements using LIBS as a simultaneous un-breakdown quantitative analysis technology, which can be applied for the safety assessment of agricultural products and precision agriculture, and to compare the results with a standardized chemical analysis method. Soil samples classified as fine-silty, mixed, thermic Typic Hapludalf(Memphis series) from grassland and uplands in Tennessee, USA were collected, crushed, and prepared for further analysis or LIBS measurement. The samples were measured using LIBS ranged from 200 to 600 nm(0.03 nm interval) with a Nd:YAG laser at 532 nm, with a beam energy of 25 mJ per pulse, a pulse width of 5 ns, and a repetition rate of 10 Hz. The optimum wavelength(${\lambda}nm$) of LIBS for estimating soil and plant elements were 308.2 nm for Al, 428.3 nm for Ca, 247.8 nm for T-C, 438.3 nm for Fe, 766.5 nm for K, 85.2 nm for Mg, 330.2 nm for Na, 213.6 nm for P, 180.7 nm for S, 288.2 nm for Si, and 351.9 nm for Ti, respectively. Coefficients of determination($r^2$) of calibration curve using standard reference soil samples for each element from LIBS measurement were ranged from 0.863 to 0.977. In comparison with ICP-AES(Inductively coupled plasma atomic emission spectroscopy) measurement, measurement error in terms of relative standard error were calculated. Silicon dioxide(SiO2) concentration estimated from two methods showed good agreement with -3.5% of relative standard error. The relative standard errors for the other elements were high. It implies that the prediction accuracy is low which might be caused by matrix effect such as particle size and constituent of soils. It is necessary to enhance the measurement and prediction accuracy of LIBS by improving pretreatment process, standard reference soil samples, and measurement method for a reliable quantification method.

Optimal Level for the Protection of Carbon Tetrachloride-induced Sprague-Dawley Rat Liver Damage by Mycelial Cultures of Lentinus edodes (Sprague-Dawley 쥐의 사염화탄소 유도 간 손상에 대한 표고버섯균사체의 효과)

  • Jang, Wook-J.;Kim, Young-S.;Ha, Yeong-L.;Park, Cherl-W.;Ha, Young-K.;Kim, Jeong-O.
    • Journal of Life Science
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    • v.20 no.5
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    • pp.782-788
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    • 2010
  • The protective effects of a powder mixed with solid-cultured and liquid-cultured Lentinus edodes mycelia (2 : 1, w/w) (designate LED) with different doses of carbon tetrachloride ($CCl_4$) on induced hepatotoxicity in male Sprague-Dawley (SD) rats was investigated. The rats were divided into seven groups (6 rats/group) and the following substances were administered orally to each group: Vehicle (0.2 ml distilled water), Control (0.2 ml distilled water), LED (LED 100, 200, 300 and 400 mg/kg BW in 0.2 ml distilled water), and Silymarin (200 mg/Kg BW in 0.2 ml distilled water). After two weeks of daily administration, all groups except for the Vehiclegroup were subjected to abdominal injection with $CCl_4$ ($CCl_4$ : corn oil, 1 : 1 v/v; 0.5 ml/kg BW). One day later, blood and liver samples were collected to analyze biomarkers. All LED treatments elevated hepatic superoxide dismutase (SOD), catalase and glutathione peroxidase (GSH peroxidase) activities, and reduced thiobarbituric reactive substances (TBARS), tumor necrosis factor-$\alpha$ (TNF-$\alpha$), interleukin-$1{\beta}$ (IL-$1{\beta}$) and interleukin-6 (IL-6), resulting in the reduction of glutamate-oxalate transaminase (GOT), glutamate-pyruvate transaminase (GPT) and lactic acid dehydrogenase (LDH) activities in plasma. These results indicate that LED effectively protected SD rat hepatotoxicity induced by $CCl_4$ through its antioxidative activity and reduction of some cytokines. The highest efficacy was found in LED 200 mg/kg BW, showing potential as a useful material for protection from hepatotoxicity in humans.

Study on the Contents of Trace Elements in Foods (on the Trace Element Contents of Shellfish in Korean coastal Water) (식품중의 미량금속에 관한 연구조사 (연안 견류중의 중금속 함유량에 관하여))

  • 백덕우;권우창;원경풍;김준한;김오한;소유섭;김영주;박건상;성덕화
    • Journal of Food Hygiene and Safety
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    • v.3 no.1
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    • pp.7-18
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    • 1988
  • In 1987, the level of heavy metals were determined ina total of 200 samples of 9 species of shellfish of Korea. The samples were collected at the fish. markets by 10 Public Institute of Health. The samples were whelk (Buccinum striatiBBimum), oyster (Crassostrea gigas), ark shell(Tegillarca granesa), shartnecked clam (Venerupis semidecussta), hard clam (Meretrix lusoria), top shell (Turbo cornutus), abalone (Haliotis gigantea), ark shell (Scapharea broughtonii), sea-mussel (Mytilus conuscus gould), respectively. The levels of total mercury, lead, cadmium, arsenic, copper, zinc and manganese were determined. The total mercury levels were determined by mercury analyzer using the combustion gold amalgamation method. The arsenic level were determined by spectrophotometry using colorimetric sil ver diethyldithiocarbamate method after dry ash dige8tion of the samples with magnesium oxide and magnesium nitrate. The levels of other metals were determined by inductively coupled pluma spectrophotometry after wet digestion of the samples with nitric acid and su1furic acid. The results were summerized as follows; 1. The overallranges and mean(ppm) were; Hg, ND-O.221 (0.036); Pb, 0.05-1.51 (0.37); Cd, 0.02-1.86 (0.61); As, 0.5-3.97 (1.22); Cu, 0.14-54.16 (4.93); Zn, 7.40-207.17 (30.09); Mn, 0.13-s.72 (3.40). 2. The levels of all 6 metals were found to be below the maximum permissible Iimits set by the Japan lor mercury, the Netherland for lead the Hong Kong for cadmium. The Finland for Arsenic no statutory Iimits for Zn and Mn in shellfish in any countries. 3. The results show that all the 9 species of shellfish studied, none have accumulated levels dangerous enough to pose a health problem.roblem.

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Disease Progression from Chronic Hepatitis C to Cirrhosis and Hepatocellular Carcinoma is Associated with Increasing DNA Promoter Methylation

  • Zekri, Abd El-Rahman Nabawy;Nassar, Auhood Abdel-Monem;El-Rouby, Mahmoud Nour El-Din;Shousha, Hend Ibrahim;Barakat, Ahmed Barakat;El-Desouky, Eman Desouky;Zayed, Naglaa Ali;Ahmed, Ola Sayed;Youssef, Amira Salah El-Din;Kaseb, Ahmed Omar;El-Aziz, Ashraf Omar Abd;Bahnassy, Abeer Ahmed
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.11
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    • pp.6721-6726
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    • 2013
  • Background: Changes in DNA methylation patterns are believed to be early events in hepatocarcinogenesis. A better understanding of methylation states and how they correlate with disease progression will aid in finding potential strategies for early detection of HCC. The aim of our study was to analyze the methylation frequency of tumor suppressor genes, P14, P15, and P73, and a mismatch repair gene (O6MGMT) in HCV related chronic liver disease and HCC to identify candidate epigenetic biomarkers for HCC prediction. Materials and Methods: 516 Egyptian patients with HCV-related liver disease were recruited from Kasr Alaini multidisciplinary HCC clinic from April 2010 to January 2012. Subjects were divided into 4 different clinically defined groups - HCC group (n=208), liver cirrhosis group (n=108), chronic hepatitis C group (n=100), and control group (n=100) - to analyze the methylation status of the target genes in patient plasma using EpiTect Methyl qPCR Array technology. Methylation was considered to be hypermethylated if >10% and/or intermediately methylated if >60%. Results: In our series, a significant difference in the hypermethylation status of all studied genes was noted within the different stages of chronic liver disease and ultimately HCC. Hypermethylation of the P14 gene was detected in 100/208 (48.1%), 52/108 (48.1%), 16/100 (16%) and 8/100 (8%) among HCC, liver cirrhosis, chronic hepatitis and control groups, respectively, with a statistically significant difference between the studied groups (p-value 0.008). We also detected P15 hypermethylation in 92/208 (44.2%), 36/108 (33.3%), 20/100 (20%) and 4/100 (4%), respectively (p-value 0.006). In addition, hypermethylation of P73 was detected in 136/208 (65.4%), 72/108 (66.7%), 32/100 (32%) and 4/100 (4%) (p-value <0.001). Also, we detected O6MGMT hypermethylation in 84/208 (40.4%), 60/108 (55.3%), 20/100 (20%) and 4/100 (4%), respectively (p value <0.001. Conclusions: The epigenetic changes observed in this study indicate that HCC tumors exhibit specific DNA methylation signatures with potential clinical applications in diagnosis and prognosis. In addition, methylation frequency could be used to monitor whether a patient with chronic hepatitis C is likely to progress to liver cirrhosis or even HCC. We can conclude that methylation processes are not just early events in hepatocarcinogenesis but accumulate with progression to cancer.

휨 구조의 압전 마이크로-켄틸레버를 이용한 진동 에너지 수확 소자

  • Na, Ye-Eun;Park, Hyeon-Su;Park, Jong-Cheol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.476-476
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    • 2014
  • 서론: 저 전력 소모를 필요로 하는 무선 센서 네트워크 관련 기술의 급격한 발달과 함께 자체 전력 수급을 위한 진동 에너지 수확 기술에 대한 연구가 활발히 이루어지고 있다. 다양한 구조와 소재를 압전 외팔보에 적용하여 제안하고 있다. 그 중에서도 진동 기반의 에너지 수확 소자는 주변 환경에서 쉽게 진동을 얻을 수 있고, 높은 에너지 밀도와 제작 방법이 간단하다는 장점을 가지고 있어 많은 분야에 응용 및 적용 가능하다. 기존 연구에서는 2차원적으로 진동 에너지 수확을 위한 휜 구조의 압전 외팔보를 제안 하였다. 휜 구조를 갖는 압전 외팔보는 각각의 짧은 두 개의 평평한 외팔보가 일렬로 연결된 것으로 볼 수 있다. 하나의 짧고 평평한 외팔보는 진동이 가해지면 접선 방향으로 응력이 생겨 최대 휨 모멘텀을 갖게 된다. 그러므로 휜 구조를 갖는 외팔보는 진동이 인가됨에 따라 길이 방향과 수직 방향으로 진동한다. 하지만, 이 구조는 수평 방향으로 가해지는 진동에 대한 에너지를 수확하기에는 한계점을 가진다. 즉, 3축 방향에서 임의의 방향에서 진동 에너지를 수확하기는 어렵다. 본 연구에서는 3축 방향에서 에너지를 효율적으로 수확할 수 있도록 헤어-셀 구조의 압전 외팔보 에너지 수확소자를 제안한다. 제안된 소자는 길이 방향과 수직 방향뿐만 아니라 수평 방향으로도 진동하여 임의의 방향에서 진동 에너지를 수확할 수 있다. 구성 및 공정: 제안하는 소자는 3축 방향에서 임의의 진동을 수확하기 위해서 길이를 길게 늘이고 길이 방향을 따라 휘어지는 구조의 헤어-셀 구조로 제작하였다. 외팔보의 구조는 외팔보의 폭 대비 길이의 비가 충분히 클 때, 추가적인 자유도를 얻을 수 있다. 그러므로 헤어-셀 구조의 에너지 수확 소자는 기본적인 길이 방향, 수직방향 그리고 수평방향에 더불어 추가적으로 뒤틀리는 방향을 통해서 3차원적으로 임의의 주변 진동 에너지를 수확하여 전기적인 에너지로 생성시킬 수 있다. 제작된 소자는 높은 종횡비를 갖는 무게 추($500{\times}15{\times}22{\mu}m3$)와 길이 방향으로 길게 휜 압전 외팔보($1000{\times}15{\times}1.7{\mu}m3$)로 구성되어있다. 공정 과정은 다음과 같다. 먼저, 실리콘 웨이퍼 위에 탄성층을 형성하기 위해 LPCVD SiNx를 $0.8{\mu}m$와 LTO $0.2{\mu}m$를 증착 후, 각각 $0.03{\mu}m$$0.12{\mu}m$의 두께를 갖는 Ti와 Pt을 하부 전극으로 스퍼터링한다. 그리고 Pb(Zr0.52Ti0.48)O3 박막을 $0.35{\mu}m$ 두께로 졸겔법을 이용하여 증착하고 상부 Pt층을 두께 $0.1{\mu}m$로 순차적으로 스퍼터링하여 형성한다. 상/하부 전극은 ICP(Inductively Coupled Plasma)를 이용해 건식 식각으로 패턴을 형성한다. PZT 층과 무게 추 사이의 보호막을 씌우기 위해 $0.2{\mu}m$의 Si3N4 박막이 PECVD 공정법으로 증착되고, RIE로 패턴을 형성된다. Ti/Au ($0.03/0.35{\mu}m$)이 E-beam으로 증착되고 lift-off를 통해서 패턴을 형성함으로써 전극 본딩을 위한 패드를 만든다. 초반에 형성한 실리콘 웨이퍼 위의 SiNx/LTO 층은 RIE로 외팔보 구조를 형성한다. 이후에 진행될 도금 공정을 위해서 희생층으로는 감광액이 사용되고, 씨드층으로는 Ti/Cu ($0.03/0.15{\mu}m$) 박막이 스퍼터링 된다. 도금 형성층을 위해 감광액을 패턴화하고, Ni0.8Fe0.2 ($22{\mu}m$)층으로 도금함으로써 외팔보 끝에 무게 추를 만든다. 마지막으로, 압전 외팔보 소자는 XeF2 식각법을 통해 제작된다. 제작된 소자는 소자의 여러 층 사이의 고유한 응력 차에 의해 휨 변형이 생긴다. 실험 방법 및 측정 결과: 제작된 소자의 성능을 확인하기 위하여 일정한 가속도 50 m/s2로 3축 방향에 따라 입력 주파수를 변화시키면서 출력 전압을 측정하였다. 먼저, 소자의 기본적인 공진 주파수를 얻기 위하여 수직 방향으로 진동을 인가하여 주파수를 변화시켰다. 그 때에 공진 주파수는 116 Hz를 가지며, 최대 출력 전압은 15 mV로 측정되었다. 3축 방향에서 진동 에너지 수확이 가능하다는 것을 확인하기 위하여 제작된 소자를 길이 방향과 수평 방향으로 가진기에 장착한 후, 기본 공진 주파수에서의 출력 전압을 측정하였다. 진동이 길이방향으로 가해졌을 때에는 33 mV, 수평방향으로 진동이 인가되는 경우에는 10 mV의 최대 출력 전압을 갖는다. 제안하는 소자가 수 mV의 적은 전압은 출력해내더라도 소자는 진동이 인가되는 각도에 영향 받지 않고, 3축 방향에서 진동 에너지를 수확하여 전기에너지로 얻을 수 있다. 결론: 제안된 소자는 3축 방향에서 진동 에너지를 수확할 수 있는 에너지 수확 소자를 제안하였다. 외팔보의 구조를 헤어-셀 구조로 길고 휘어지게 제작함으로써 기본적인 길이 방향, 수직방향 그리고 수평방향에 더불어 추가적으로 뒤틀리는 방향에서 출력 전압을 얻을 수 있다. 미소 전력원으로 실용적인 사용을 위해서 무게추가 더 무거워지고, PZT 박막이 더 두꺼워진다면 소자의 성능이 향상되어 높은 출력 전압을 얻을 수 있을 것이라 기대한다.

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The Effect of Aerobic Exercise on Body Composition, Cardiopulmonary Function, Serum Lipid and Antioxidants of Obese College Female Students (에어로빅운동이 비만여대생의 신체조성, 심폐기능, 혈청지질 및 항산화물질에 미치는 영향)

  • Jung Eun-Sook;Park Hyeong-Sook
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.5 no.1
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    • pp.125-141
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    • 1998
  • The purpose of this research is to analyze the effects of aerobic exercise on body composition, cardiopulmonary function, serum lipid level and antioxidants of obese and normal college female students. The subject group was made up of 13 normal students (below 30% body fat ratio) and 12 obese students (above 30% body fat ratio). After a pretest, the subjects were given an 8-week aerobic program. Then the subjects were given a posttest and analyzed of body composition, serum lipid level, antioxidants and cardiopulmonary function after the 6th and the 8th week of the program. The program schedule was made up of 4 days per week, 60 minutes per day. Test includes B.W., subscapular and triceps subcutaneous fat thickness, change of respiratory gas, and two blood sampling before treadmill exercise and post all out state, which analyzed serum lipid and antioxidants. The subjects performed treadmill exercise starting with 4km/hr of walking and then gradually increase the speed of 1km/hr per minute until all out state. The obtained data were analyzed using SAS program. The statistical methods employed here were one-way ANOVA with repeated measure, Duncan Multiple range test, paired-t test and t-test. The test results and conclusion of this research were as follows. 1. The effects of aerobic exercise on body composition were as follows ; Percent body fat was significantly reduced 6 weeks after the program and lean body mass was significantly increased 8 weeks after the program in both groups(obese group: F=3.44 P=.044, normal group: F=3.30 P=.048). subscapular skinfold of the obese group showed a remarkable decrease after the 6th week(F=4.33 P=.021) triceps skinfold of the normal group showed a remarkable decrease after the 6th and the 8th week(F=4.55 P=.017) compared with readings before the aerobic program, the aerobic program made a bigger difference concerning body fat, lean body mass, subscapular skinfold in the obese group than in the normal group(t=2.41 P=.024, t=2.40 p=.025, t=2.43 p=.028). 2. The effects of aerobic exercise on cardiopulmonary function were as follows ; Maximal $O_2$ uptake/kg was significantly increased 6 weeks after the program in the obese group(F=3.20 P=.054), but not much difference was observed in the normal group. Maximal pulse rate was significantly reduced in both groups after 6 weeks of the program(obese group: F=2.77 P=.087, normal group: F=7.17 P=.001). 3. The effects of aerobic exercise on serum lipid level were as follows ; In a resting period, total cholesterol, Triglyceride, and LDL-cholesterol were slightly higher in the obese group than in the normal group, but HDL-cholesterol was higher in the normal group. But, with the aerobic program, total-cholesterol, Triglyceride, LDL-cholesterol were reduced gradually and HDL-choleterol got increased in both groups, but not much change was noticed in the normal group. However, in the obese group, serum HDL-cholesterol level got increased significantly(F=5.12 P=.012). 4. The effects of aerobic exercise in serum antioxidants were as follows ; In a resting period, the obese group's serum Free Radical and GSSG content were higher than the normal group's and the normal group's serum GSH content was higher than the obese group's. After 6 weeks of the aerobic program, Free Radical was reduced significantly in both groups(obese group: F=13.87 P=.000, normal group: F=18.60 P=.000) In the obese group, 8 weeks after the program, GSH was increased significantly(F=13.78, P=.000). In the normal group, 6 weeks after the program, GSH was reduced but increased again after 8 weeks(F=6.07 P=.005). Plasma GSSG was significantly increased after 8 weeks of exercise in both groups(obese group: F=19.75 P=.000, normal group: F=22.42 P=.000,) Compared with readings before the aerobic program, the aerobic program made a bigger difference serum GSH in the normal group than in the obese group(t=3.37 p=.003). As this result shows, it is known that the regular aerobic exercise improves cardiopulmonary function, body composition, serum lipid effectively and through the serum Free Radical reduction and antioxidant system activation, oxidant stress was suppressed. This effect was higher in the obese group than in the normal one. At least 6weeks exercise period need for improvement of body composition, cardiopulmonary function and activation of antioxidant system. This result suggest that improvement of serum lipid profile was needed longer than 8weeks exercise period.

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Analysis of Trans Fatty Acid Content in Processed Foods and Meat Products (가공식품과 육가공품의 트랜스 지방산 함량 조사)

  • Park, Jung-Min;Ji, Won-Gu;Kim, Eun-Jung;Park, Da-Jung;Shin, Jin-Ho;Shim, Soon-Mi;Suh, Hyung-Joo;Chang, Un-Jae;Kang, Duk-Ho;Kim, Jin-Man
    • Food Science of Animal Resources
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    • v.27 no.4
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    • pp.531-537
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    • 2007
  • Small amounts of trans fatty acids exist naturally in beef and dairy foods. Also, they can be produced in the process of partial hydrogenation to manufacture shortning or margarine. They can provide a better palatability and shelf life. According to the recently studies, trans fatty acids can raise health risk such as heart diseases and coronary artery diseases. They can also increase low-density lipoprotein (LDL) cholesterol and decrease high-density lipoprotein (HDL) cholesterol in the blood plasma, therefore increasing the risk of atherosclerosis and diabetes. The aim of this study was to determine total lipids and trans fatty acids (TFAs) content in processed foods and meat products. The analysis of trans fatty acids was performed in 28 samples of donuts, 18 samples of bakeries, 4 samples of frozen doughs, 2 samples of popcorns, and 4 samples of meat products (ham, sausage, nuget, and bacon). Total lipids in processed foods and meat products were extracted by chloroform-Methanol method and acid digestion, respectively. They were analyzed by gas chromatography using a SP-2560 column and flame ionization detector. The amounts of TFAs per 100 g of foods were 0-3.3% (0.74% on average) in donuts, 0.2-5.8% (1.18% on average) in bakeries, 0.2-6.3% (1.93% on average) in frozen doughs, and 0-5.8% in popcorns. Meat products such as ham, sausage, and nuget analyzed 0.1% of TFAs, respectively and trans fatty acids in bacon were not detected. As a result, the distribution of TFAs in processed foods was widely ranged from O% to 6.3% according to manufacturers and types of products, whereas the content of TFAs in meat products ranged from 0% to 0.1%.

Selective determination of mercury (II) ion in aqueous solution by chemiluminescence method (화학발광법에 의한 수용액 중의 선택적 수은(II) 이온 정량)

  • Kim, Kyung-Min;Jang, Taek-Gyun;Kim, Young-Ho;Oh, Sang-Huyb;Lee, Sang-Hak
    • Analytical Science and Technology
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    • v.24 no.4
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    • pp.243-248
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    • 2011
  • A selective determination method of mercury (II) ion in aqueous solution by luminol-based chemiluminescence system (luminol CL system) has been developed. Determination of metal ions such as copper (II), iron (III), chromium (III) ion in solution by the luminol CL system using its catalytic role in the reaction of luminol and hydrogen peroxide has been reported by several groups. In this study, the catalytic activity of mercury (II) ion in the reaction of luminol and hydrogen peroxide was observed by the enhanced CL intensity of the luminol CL system. Based on this phenomenon, experimental conditions of the luminol CL system were investigated and optimized to determine mercury (II) ion in aqueous solution. While mercury (II) ion in mixed sample solution containing mercury (I) and (II) ions highly enhanced the CL intensity of the luminol CL system, the mercury (I) ion could not enhanced the CL intensity. Thus selective determination of the mercury (II) ions in a mixture containing mercury (I) and (II) ions could be achieved. Each concentration of mercury (I) and (II) ions in aqueous solution can be obtained from the results of the CL method that give the concentration of only mercury (II) ion and the inductively coupled plasma (ICP) method that give the total concentration of mercury ions. On the optimized conditions, the calibration curve of mercury (II) ion was linear over the range from $1.25{\times}10^{-5}$ to $2.50{\times}10^{-3}M$ with correlation coefficient of 0.991. The detection limit of mercury (II) ion in aqueous solution was calculated to be $1.25{\times}10^{-7}M$.

Carbon nanotube field emission display

  • Chil, Won-Bong;Kim, Jong-Min
    • Electrical & Electronic Materials
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    • v.12 no.7
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    • pp.7-11
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    • 1999
  • Fully sealed field emission display in size of 4.5 inch has been fabricated using single-wall carbon nanotubes-organic vehicle com-posite. The fabricated display were fully scalable at low temperature below 415$^{\circ}C$ and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1V/${\mu}{\textrm}{m}$ and field emis-sion current of 1.5mA at 3V/${\mu}{\textrm}{m}$ (J=90${\mu}{\textrm}{m}$/$\textrm{cm}^2$)were observed. Brightness of 1800cd/$m^2$ at 3.7V/${\mu}{\textrm}{m}$ was observed on the entire area of 4.5-inch panel from the green phosphor-ITO glass. The fluctuation of the current was found to be about 7% over a 4.5-inch cath-ode area. This reliable result enables us to produce large area full-color flat panel dis-play in the near future. Carbon nanotubes (CNTs) have attracted much attention because of their unique elec-trical properties and their potential applica-tions [1, 2]. Large aspect ratio of CNTs together with high chemical stability. ther-mal conductivity, and high mechanical strength are advantageous for applications to the field emitter [3]. Several results have been reported on the field emissions from multi-walled nanotubes (MWNTs) and single-walled nanotubes (SWNTs) grown from arc discharge [4, 5]. De Heer et al. have reported the field emission from nan-otubes aligned by the suspension-filtering method. This approach is too difficult to be fully adopted in integration process. Recently, there have been efforts to make applications to field emission devices using nanotubes. Saito et al. demonstrated a car-bon nanotube-based lamp, which was oper-ated at high voltage (10KV) [8]. Aproto-type diode structure was tested by the size of 100mm $\times$ 10mm in vacuum chamber [9]. the difficulties arise from the arrangement of vertically aligned nanotubes after the growth. Recently vertically aligned carbon nanotubes have been synthesized using plasma-enhanced chemical vapor deposition(CVD) [6, 7]. Yet, control of a large area synthesis is still not easily accessible with such approaches. Here we report integra-tion processes of fully sealed 4.5-inch CNT-field emission displays (FEDs). Low turn-on voltage with high brightness, and stabili-ty clearly demonstrate the potential applica-bility of carbon nanotubes to full color dis-plays in near future. For flat panel display in a large area, car-bon nanotubes-based field emitters were fabricated by using nanotubes-organic vehi-cles. The purified SWNTs, which were syn-thesized by dc arc discharge, were dispersed in iso propyl alcohol, and then mixed with on organic binder. The paste of well-dis-persed carbon nanotubes was squeezed onto the metal-patterned sodalime glass throuhg the metal mesh of 20${\mu}{\textrm}{m}$ in size and subse-quently heat-treated in order to remove the organic binder. The insulating spacers in thickness of 200${\mu}{\textrm}{m}$ are inserted between the lower and upper glasses. The Y\ulcornerO\ulcornerS:Eu, ZnS:Cu, Al, and ZnS:Ag, Cl, phosphors are electrically deposited on the upper glass for red, green, and blue colors, respectively. The typical sizes of each phosphor are 2~3 micron. The assembled structure was sealed in an atmosphere of highly purified Ar gas by means of a glass frit. The display plate was evacuated down to the pressure level of 1$\times$10\ulcorner Torr. Three non-evaporable getters of Ti-Zr-V-Fe were activated during the final heat-exhausting procedure. Finally, the active area of 4.5-inch panel with fully sealed carbon nanotubes was pro-duced. Emission currents were character-ized by the DC-mode and pulse-modulating mode at the voltage up to 800 volts. The brightness of field emission was measured by the Luminance calorimeter (BM-7, Topcon).

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