• Title/Summary/Keyword: school stress

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Evaluation of Compression Index for Natural Clay Using the Compression Characteristic of Reconstituted Clay (재성형점토의 압축특성을 이용한 자연점토의 압축지수 추정)

  • Hong, Sung-Jin;Kim, Dong-Hee;Lee, Moon-Joo;Jie, Hong-Keun;Lee, Woo-Jin
    • Journal of the Korean Geotechnical Society
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    • v.29 no.3
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    • pp.5-13
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    • 2013
  • The compression index, representing the compressibility of clay, is generally obtained from the consolidation test, or predicted by empirical correlations using soil properties. However, empirical methods have regional limitations, because the compression index is affected not only by soil properties but also by site characteristics, such as deposition conditions and stress history. In this study, a method evaluating the compression index from typical soil properties is suggested using the characteristics of reconstituted clay. By analyzing the consolidation test results of Busan clay, the suggested method is verified, and the analysis of prediction error is carried out. It is shown that the proposed method evaluates the compression index more accurately than empirical methods previously suggested. The prediction errors occur by assumption, and are inversely proportional to $e_{cross}/e_0$, obviously.

Body Mass Index, Dietary Intake, Serum Lipids and Antioxidant Status of Young Females (여대생의 BMI에 따른 식이섭취와 혈중지질 농도 및 항산화능)

  • Bae Hyun-Sook
    • Korean Journal of Community Nutrition
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    • v.11 no.4
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    • pp.479-487
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    • 2006
  • Many epidemiological and observational studies show that distorted body image of normal body weight is widespread among Korean young females. This study was performed to evaluate the prevalence of overweight and underweight of young females and, to compare nutrient intakes, body composition, serum indices (lipids, MDA: Malondialdehyde, TAS : Total Antioxidant Status) with different BMI groups. The subjects were 75 university students in Seoul. We divided the subjects into 3 groups according to their BMI by IOTF guideline (UW: underweight group, BMI < 18.5, NW: normal body weight group; 18.5 $\leq$ BMI < 23.0, OW: overweight group; BMI $\geq$ 23.0). Data on dietary intakes, body compositions and serum indices were obtained in 3 groups. Differences on all of the above variables were assessed by body weight groups. Using IOTF guidelines, the prevalence of overweight and underweight in young females were 23%, 61%, 16% respectively. $\beta$-carotene and vitamin A intake of UW were significantly higher than that of NW (p < 0.05). Fiber intakes of NW was significantly higher than that of W (p < 0.05). But intakes of energy and the other nutrients were not significantly different among BMI groups. Calcium and folate intakes were 75%, 61% of KDRIs. Serum TGs were significantly higher in OW than that of NW, UW (p < 0.05), but level of MDA and TAS were not significantly different. The association of overweight and low intake of $\beta$-carotene and vitamin A may be one of many factors predisposing obese females to a high risk of oxidative stress later in life. This requires urgent nutritional intervention programs involving enough intake of fruit and vegetables, with modification of inappropriate dietary habits.

The Effects of Smoking on Antioxidative Enzyme Activities in Male Adolescents (흡연이 남자 청소년들의 일부 항산화 관련 효소체계에 미치는 영향)

  • 임재연;김정희
    • Korean Journal of Community Nutrition
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    • v.7 no.6
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    • pp.844-851
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    • 2002
  • Smoking can increase oxidative stress and thereby change the antioxidant defense system in the body. To investigate the relationship between male adolescent smoking and antioxidant status, we surveyed the eating habits and dietary intake of 82 smokers and 44 nonsmokers recruited from a male technical high school. In addition, antioxidant enzyme activity and lipid peroxide values were determined in both the plasma and the erythrocytes. Although the frequency of food intake was not significantly different, most nutrient intake was unexpectedly higher in smokers than in nonsmokers. In comparison with the Korean RDA, especially the average intake of Ca, Fe and vitamin $B_2$ didn t reach 75% of the Korean RDA in either smokers or nonsmokers. An analysis of antioxidant enzyme activity showed that plasma catalase. superoxide dismutase (SOD), glutathione peroxidase (GSH-px), erythrocyte catalase and GSH-px activities showed no significant difference between smokers and nonsmokers. However, the erythrocyte SOD activity of smokers (1.57 unit/mgHb) was significantly lower than that of nonsmokers (2.00 unit/mg Hb). In addition, the plasma ceruloplasmin concentration of smokers (28.68 mg/$d\ell$) was significantly higher than that of nonsmokers (26.30 mg/$d\ell$), whereas the specific ceruloplasmin ferroxidase activity of smokers (0.31 unit/mg) was lower than that of nonsmokers (0.35 unit/mg). The plasma and erythrocyte thlobarbituric acid reactive substance (TBARS) of smokers (2.57 $\mu$mol/L, 0.32 $\mu$mol/gHb) were also significantly higher than those of nonsmokers (2.25 $\mu$mol/L, 0.27 $\mu$mol/gHb). The overall data indicate that adolescent smoking might decrease the antioxidant capacity of the body, in part, by lowering the erythrocyte SOD activity and the specific ceruloplasmin ferroxidase activity.

Prediction of Spring Rate and Initial Failure Load due to Material Properties of Composite Leaf Spring (복합재 판스프링의 재료특성에 따른 스프링 강성변화와 초기 파단하중 예측)

  • Oh, Sung Ha;Choi, Bok Lok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.12
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    • pp.1345-1350
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    • 2014
  • This paper presented analysis methods for adapting E-glass fiber/epoxy composite (GFRP) materials to an automotive leaf spring. It focused on the static behaviors of the leaf spring due to the material composition and its fiber orientation. The material properties of the GFRP composite were directly measured based on the ASTM standard test. A reverse implementation was performed to obtain the complete set of in-situ fiber and matrix properties from the ply test results. Next, the spring rates of the composite leaf spring were examined according to the variation of material parameters such as the fiber angles and resin contents of the composite material. Finally, progressive failure analysis was conducted to identify the initial failure load by means of an elastic stress analysis and specific damage criteria. As a result, it was found that damage first occurred along the edge of the leaf spring owing to the shear stresses.

Spatial Randomness of Fatigue Crack Growth Rate in Friction Stir Welded 7075-T651 Aluminum Alloy Welded Joints (Case of LT Orientation Specimen) (마찰교반용접된 7075-T651 알루미늄 합금 용접부의 피로균열전파율의 공간적 불규칙성 (LT 방향의 시험편에 대하여))

  • Jeong, Yeui Han;Kim, Seon Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.9
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    • pp.1109-1116
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    • 2013
  • This study aims to investigate the spatial randomness of fatigue crack growth rate for the friction stir welded (FSWed) 7075-T651 aluminum alloy joints. Our previous fatigue crack growth test data are adopted in this investigation. To clearly understand the spatial randomness of fatigue crack growth rate, fatigue crack growth tests were conducted under constant stress intensity factor range (SIFR) control testing. The experimental data were analyzed for two different materials-base metal (BM) and weld metal (WM)-to investigate the effects of spatial randomness of fatigue crack growth rate and material properties, the friction stir welded (FSWed) 7075-T651 aluminum alloy joints, namely weld metal (WM) and base metal (BM). The results showed that the variability, as evaluated by Weibull statistical analysis, of the WM is higher than that of the BM.

Antioxidant Activity of Pepsin Hydrolysate Derived from Edible Hippocampus abdominalis in vitro and in Zebrafish Models (빅벨리 해마(Hippocampus abdominalis) 유래 펩신 가수분해물의 In vitro와 In vivo에서의 항산화 효능)

  • Kim, Hyun-Soo;Shin, Byeung-Ok;Kim, Seo-Young;Wang, Lei;Lee, WonWoo;Kim, Yoon Taek;Rho, Sum;Cho, Moonjae;Jeon, You-Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.4
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    • pp.445-453
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    • 2016
  • Seahorse Hippocampus abdominalis a marine teleost fish, has long been used as one of the essential materials in traditional Chinese medicine. However, the uses of seahorse have been limited due to its high cost, despite its beneficial biological activities. Seahorse has not been widely explored for its biofunctional properties and active components. In the present study, the enzymatic hydrolysates of seahorse were prepared by using two digestive enzymes (trypsin and pepsin) and five food grade enzymes (neutrase, protamex, alcalase, kojizyme, and flavourzyme). The enzymatic hydrolysates indicated higher hydrolysis yields than its water extract. Among them, the distilled water-pepsin hydrolysate (DP) which was obtained by distilled water extraction followed by pepsin hydrolysis, showed the highest yield and protein content as well as the highest alkyl radical scavenging activity. Also, it provided protective effects against oxidative stress induced by AAPH in vero cell and zebrafish. Further fractionation based on the molecular weight was carried out to identify it’s active components, and < 5 kDa (less than 5 kDa) molecular weight fraction was confirmed to have the highest antioxidant activity. In conclusion, this study suggests that DP of seahorse has antioxidant properties, and might be a novel and useful material from the marine origin for healthy functional foods and cosmetics.

A Study on the Theory of Chimibyeong(治未病) (치미병(治未病) 사상 연구)

  • Min, Jin-Ha;Baik, You-Sang;Jang, Woo-Chang;Jeong, Chang-Hyun
    • Journal of Korean Medical classics
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    • v.23 no.1
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    • pp.257-277
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    • 2010
  • The purpose of this article is to oversee the theory of Chimibyeong(治未病). The aim of Chimibyeong theory is to prevent disease from occuring, worsening, being delivered and so on. In many books, the word Chimibyeong was used as an alternative name for Yangsaeng(養生) or used as a term of preventing a disease or used as a word meaning treating disease in the early stage. But after the period of "Nangyeong(難經)", people extend the meaning of Chimibyeong to all stages of a disease covering the healthy stage, the early stage, the progressive, and the recovery stage of a disease. Especially in urgent cases when pathogenic factor[邪氣] attacks patient to critical situations, it is also regarded as one way of Chimibyeong to repel pathogenic factor out as soon as possible with proper medicines. These days people suffer from increasing mental stress, lack of rest and human relationships, environmental pollution and chronic diseases and so on, and the situation will grow worse. Many governments employ the health policy where preventing disease takes the highest priority because by doing that they can save a huge budget and minimize the economic and social disorder. In this circumstances the idea of pursuing prevention in the theory of Chimibyeong will help people to maintain healthy conditions.

A Study on the Dietary Nutrient Intakes and Blood Profiles of Smoking Teenage Girls Living in a Rural Community in Korea (일부 농촌 지역 흡연 여고생의 영양 섭취 및 혈액 성상 조사)

  • 김선효;신호상;임우경
    • Journal of Nutrition and Health
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    • v.34 no.3
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    • pp.338-347
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    • 2001
  • Cigarette smoking has a negative effect for nutrient intakes and nutritional status of antioxidant nutrients including vitamin C. This study has been performed to compare the dietary nutrient intakes, serum vitamin C concentration and serum cotinine concentration of smoking teenage girls(n=104) with those of non-smoking teenage girls(n=791). The subjects were 895 high school girls(15-19 years of age) living in a rural community in Korea. Of the subjects, 11.6% stated that they were currently smoking. The frequency of taking alcohol, soda and coffee was higher in smokers than in non-smokers, respectively. The usage rate of vitamin/mineral supplements was higher in smokers than in non-smokers. The smokers tended to skip breakfast and lunch and to take snack more often than did the non-smokers. The dietary intakes of calorie, protein, vitamin A, vitamin B, vitamin C, calcium and iron were lower in smokers than in non-smokers. Daily mean intakes of these nutrients were less than the 2/3 of the Korean RDAs in smokers while these intakes were similar to or more than the RDAs in non-smokers. The ratio of under weight or lean tended to be higher in smokers. Serum vitamin C concentration was lower in smokers than in non-smokers. These findings show that smokers have unsound eating habits and poor nutirtional status. In particular, nutritional status of vitamin C is significantly poor in smokers, and this tendency can be found more notably in heavy smokers. Therefore, oxidative stress may be present in young teenage girls with short smoking history as evidence by above results. (Korean J Nutrition 34(3) : 338∼347, 2001)

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Comparisons of Chicken Muscles between Layer and Broiler Breeds Using Proteomics

  • Jung, K. C.;Jung, W. Y.;Lee, Y. J.;Yu, S. L.;Choi, K. D.;Jang, B. G.;Jeon, J. T.;Lee, J. H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.3
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    • pp.307-312
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    • 2007
  • The present study was carried out to investigate differentially expressed chicken muscle proteins using proteomics approach. More than 300 protein spots were investigated for the muscle samples in 2DE gels and the differentially expressed protein spots between pectoralis and peroneus longus muscles from Cornish and White Leghorn breeds were characterized by MALDI-TOF. In pectoralis muscles, PGAM1 protein was detected as differentially expressed between White Leghorn and Cornish breeds. On the other hand, 4 protein spots (SP22, nxf-2, SOD1, TNNI2) were differentially expressed between White Leghorn and Cornish breeds in peroneus longus muscles. These proteins assumed to be related with muscle development, growth, stress, and movements in chicken. In this experimental process, 2D reference map of the chicken muscle proteins was needed and 25 proteins, which were commonly expressed in both pectoralis and peroneus longus muscles in both breeds, were selected and characterized. Upon finishing the exact roles of the differentially expressed proteins, the identified 5 proteins will be used as valuable information for the fundamental mechanisms of muscle biology and underline genetics.

Determination of Nutrient Contents and In vitro Gas Production Values of Some Legume Forages Grown in the Harran Plain Saline Soils

  • Boga, M.;Yurtseven, S.;Kilic, U.;Aydemir, S.;Polat, T.
    • Asian-Australasian Journal of Animal Sciences
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    • v.27 no.6
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    • pp.825-831
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    • 2014
  • The aim of this study was to determine the nutritive value of some legume species in salt-affected soils of South-East Anatolian region using chemical composition and in vitro gas production kinetics. In this study, Lotus corniculatus, Trifolium alexandrinum, Medicago sativa were sown and tested in four different locations. A 3 by 4 factorial design with 3 legume species and 4 salt levels (non salty electrical conductivity (EC)<4 dS/m; low salt: 4 dS/m>EC<8 dS/m, medium saline: 8 dS/m>EC<16 dS/m and high salt: 16 dS/m>EC) was used in the study. Results indicated that salinity and plants had no significant effect on ash and ether extract. Dry matter (DM), acid detergent fiber, digestible dry matter, dry matter intake (DMI) were affected by plant, salinity and plant${\times}$salinity interaction. On the other hand neutral detergent fiber, relative feed value (RFV), and DMI were affected by salinity and plant${\times}$salinity interaction. Mineral contents were affected by plant species, salinity and salinity${\times}$plants interactions. In vitro gas production, their kinetics and estimated parameters such as were not affected by salinity whereas the gas production up to 48 h, organic matter digestibility, metabolizable energy (ME), and net energy lactation ($NE_L$) were affected by plant and plant${\times}$salt interaction. Generally RFVs of all species ranged from 120 to 210 and were quite satisfactory in salty conditions. Current results show that the feed value of Medicago sativa is higher compared to Lotus corniculatus and Trifolium alexandrinum.