• Title/Summary/Keyword: Stress Concentration Effect

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The Study on Local Composite Behavior of Connection Member between Steel Pipe Pile and Concrete Footing (강관 말뚝 기초 두부 연결부의 합성거동에 대한 연구)

  • You, Sung-Kun;Park, Jong-Myen;Park, Dae-Yong;Kim, Young-Ho;Kang, Won-Ho
    • Journal of the Korea Concrete Institute
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    • v.15 no.2
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    • pp.288-296
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    • 2003
  • Generally, application of steel pipe pile as deep foundation member needs special requirement for the connection method between steel pipe pile and concrete footing. Even though two types of connection method are suggested in the related specification, type B-method is provident. To investigate real structural behavior of type B connection, several load tests are done with carefully designed experimental system. The purpose of this experiment is mainly focused on the understanding of actual behavior which can be predicted by design theory. At this research stage, vertical and lateral loading test are done for three types of specimen to review stress concentration, formation and behavior of imaginary RC column in the footing and effect of non-slip device installed in the steel pipe pile. The load resistance mechanism in these specific connection method is predicted based on both experimental results. The three-dimensional finite element modeling is also done for the purpose of comparison between numerical and experimental result. With all the results gained from experiment the structural behavior of imaginary RC column in the design concept is confirmed. The role of non-slip device is very important and it affects the resistance capacity with help of composite action of concrete and steel pipe pile.

Effects of different space allowances on growth performance, blood profile and pork quality in a grow-to-finish production system

  • Jang, J.C.;Jin, X.H.;Hong, J.S.;Kim, Y.Y.
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.12
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    • pp.1796-1802
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    • 2017
  • Objective: This experiment was conducted to evaluate the optimal space allowance on growth performance, blood profile and pork quality of growing-finishing pigs. Methods: A total of ninety crossbred pigs [$(Yorkshire{\times}Landrace){\times}Duroc$, $30.25{\pm}1.13kg$] were allocated into three treatments (0.96: four pigs/pen, $0.96m^2/pig$; 0.80: five pigs/pen, $0.80m^2/pig$; 0.69: six pigs/pen, $0.69m^2/pig$) in a randomized complete block design. Pigs were housed in balanced sex and had free access to feed in all phases for 14 weeks (growing phase I, growing phase II, finishing phase I, and finishing phase II). Results: There was no statistical difference in growing phase, but a linear decrease was observed on average daily gain (ADG, p<0.01), average daily feed intake (ADFI, p<0.01), and body weight (BW, p<0.01) with decreasing space allowance in late finishing phase. On the other hand, a quadratic effect was observed on gain to feed ratio in early finishing phase (p<0.03). Consequently, overall ADG, ADFI, and final BW linearly declined in response to decreased space allowance (p<0.01). The pH of pork had no significant difference in 1 hour after slaughter, whereas there was a linear decrease in 24 h after slaughter with decreasing space allowance. Floor area allowance did not affect pork colors, but shear force linearly increased as floor space decreased (p<0.01). There was a linear increase in serum cortisol concentration on 14 week (p<0.05) with decreased space allocation. Serum IgG was linearly ameliorated as space allowance increased on 10 week (p<0.05) and 14 week (p<0.01). Conclusion: Data from current study indicated that stress derived from reduced space allowance deteriorates the immune system as well as growth performance of pigs, resulting in poor pork quality. Recommended adequate space allowance in a grow-to-finish production system is more than $0.80m^2/pig$ for maximizing growth performance and production efficiency.

Antioxidant Activity and Physiological Function of the Anomala albopilosa Extracts (청동풍탱이(Anomala albopilosa)추출물의 항산화성 및 생리기능)

  • Yoon, Weon-Jong;Lee, Jung-A;Kim, Ji-Young;Kim, Sang-Bum;Park, Soo-Yeong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.6
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    • pp.670-677
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    • 2007
  • We analyzed antioxidant and physiological activities to investigate the functional effects of ethanol extracts of Anomala albopilosa imago and A. albopilosa larva. In order to effectively screen for anti-inflammatory agents, we first investigated the antioxidant activities such as DPPH radical scavenging capacity, superoxide radical scavenging capacity, xanthine oxidase inhibitory activity, and nitric oxide scavenging capacity of the A. albopilosa extracts. By the screening system, we found that A. albopilosa extracts had antioxidant activity which increased with increments of the extract concentration. Moreover, we examined the inhibitory effect of the A. albopilosa extracts on the production of anti-inflammatory factors that the nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and prostaglandin $E_2\;(PGE_2)$ production activated with LPS ($1{\mu}g/mL$) in murine macrophage cell line RAW 264.7. A. albopilosa extracts potentially inhibited the iNOS and COX-2 in a dose-dependent manner. The inhibition of iNOS activity was correlated with the decrease in nitrite levels. Additionally, the $PEG_2$ production is markedly inhibited after a treatment with the A. albopilosa extracts.

Spermatogenic and Antioxidant Potential of Mucuna prureins (L.) in Epididymal Spermatozoa: A Dose Dependent Effect

  • Suresh, Sekar;Prithiviraj, Ealumali;Venkatalakshmi, Nagella;Ganesh, Mohanraj Karthik;Ganesh, Lakshmanan;Lee, Hyun-Jeong;Prakash, Seppan
    • Reproductive and Developmental Biology
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    • v.35 no.4
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    • pp.441-447
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    • 2011
  • The study aim is to investigate the free radicals scavenging and spermatogenic potentials, as well as to analyze any reproductive toxicity of ethanolic extract of Mucuna prureins (M. pruriens) Linn. in spermatozoa, under different dosages in normal male rat. Normal rats were randomly selected and suspension of the extract was administered orally at the dosages of 150, 200 and 250 mg/kg body weight of the different groups of male rats (n=6) once in a day for 60 days and grouped as group II, III and IV respectively. Saline treated rats served as control -group I. On the $60^{th}$ day the animals were sacrificed and the epididymal sperm were subjected to various analyses like level of ROS production, LPO, enzymatic and non enzymatic antioxidant, morphology, morphometry, chromosomal integrity and DNA damage. Results showed significant reduction in ROS production and peroxidation and significant increase in both enzymic and non-enzymic antioxidants in all concentration treated groups when compared with control. Results from all the drug treated groups showed good sperm morphology, increased sperm count and motility. There was no DNA damage and showed normal chromosomal integrity even in 250 mg/kg dose. When compared with control all the three extract treated groups showed increased ROS scavenging activity. However, group II (200 mg/kg) showed significant changes in all the parameters. From the present study it was confirmed that the M. pruriens has potential to improve the sperm qualitatively and quantitatively through scavenging the excess ROS with any adverse side effects. These observations suggest that ethanolic seed extract of M. pruriens may serve as anti-oxidant that can exploit to treat the oxidative stress mediated male factor infertility.

Bile Duct Obstruction Stimulates Lipid Peroxidation and Liver Fibrosis (Cirrhosis) in Rat (랫드에서 담도폐쇄에 의한 지질과산화와 간섬유화(경화) 촉진에 관한 연구)

  • 김기영;서의석;임진아
    • Toxicological Research
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    • v.17 no.3
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    • pp.187-194
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    • 2001
  • The oxidative stress causes the cell damage and death and thereby, stimulates membrane lipid peroxidation. In this study, the correlation between the lipid peroxidation product and the parameter of liver fibrosis (cirrhosis) was investigated in cholestasis induced rats. The Sprague-Dawley rats were divided into 3 groups (sham: sham operation, BDL/S-I and BDL/S-II : bile duct ligation/scission) and were observed for 2 or 4 weeks. After observation period, the organs were weighed and the ratio of organ weight/body weight was calculated. Sera and liver tissue were used for the measurement of malondealdehyde (MDA), parameter of clinical biochemistry, total collagen content and the staining. The ratio of organ weight/body weight in BDL/S-I and BDL/S-II was significantly increased compared to sham operated group. Serological parameters (Alanine transaminase, Aspartate transaminase, Alkaline phosphatase and Total bilirubin) in BDL/S-I and BDL/S-II group were significantly higher than those in sham operated group. Concentration of MDA in BDL/S-I (261%) and BDL/S-II(790%) was significantly increased compared to MDA in sham operated group. And the content of hydroxyproline (hyp) in BDL/S-I and BDL/S-II group was significantly increased 2~4 times than in sham operated group. The good correlations between hyp in liver tissue and MDA in sera of sham operated group and all operated group were found (r=0.825). The significantly higher value of MDA, hyp and serological parameters in BDL/S-I and BDL/S-II group suggests the stimulation of lipid peroxidation and chronic liver damage. Especially the activation of lipid peroxidation and the stimulation of liver fibrosis was stronger in BDL/S-II group than in BDL/S-I group. The stronger fibrosis, portal-portal septum formation, the more massive bile duct proliferation in portal triads and stroma, and hepatocytes swelling were observed in liver tissue of and BDL/S-II group compared to BDL/S-I group. Conclusively, a good correlation between MDA as a lipid peroxidation marker and hyp as a liver fibrotic parameter could be connected with the process of liver fibrosis. Moreover, cholestasis condition may cause jaundice, activation of lipid peroxidation, and collagen accumulation in liver. Additionally, optimal observation period of bile duct obstruction for the screening of antioxidant and antifibrotic effect in rats would be four weeks.

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Evaluation of Size for Crack around Rivet Hole Using Lamb Wave and Neural Network (초음파 판파와 신경회로망 기법을 적용한 리뱃홀 부위의 균열 크기 평가)

  • Choi, Sang-Woo;Lee, Joon-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.4
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    • pp.398-405
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    • 2001
  • The rivet joint has typical structural feature that can be initiation site for the fatigue crack due to the combination of local stress concentration around rivet hole and the moisture trapping. From a viewpoint of structural assurance, it is crucial to evaluate the size of crack around the rivet holes by appropriate nondestructive evaluation techniques. Lamb wave that is one of guided waves, offers a more efficient tool for nondestructive inspection of plates. The neural network that is considered to be the most suitable for pattern recognition has been used by researchers in NDE field to classify different types of flaws and flaw sizes. In this study, clack size evaluation around the rivet hole using the neural network based on the back-propagation algorithm has been tarried out by extracting some features from the ultrasonic Lamb wave for A12024-T3 skin panel of aircraft. Special attention was paid to reduce the coupling effect between the transducer and the specimen by extracting some features related to time md frequency component data in ultrasonic waveform. It was demonstrated clearly that features extracted from the time and frequency domain data of Lamb wave signal were very useful to determine crack size initiated from rivet hole through neural network.

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The Effect of Isoflavone and Gamma-linolenic Acid Supplementation on Serum Lipids and Menopausal Symptoms in Postmenopausal Women (폐경 후 여성에서 이소플라본과 감마 리놀렌산의 보충 섭취가 혈중 지질 농도 및 갱년기 증상에 미치는 영향)

  • Gwak, Jung-Hyun;Kim, Ji-Young;Kim, Hyae-Jin;Shin, Dong-Hyeok;Lee, Jong-Ho
    • Journal of Nutrition and Health
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    • v.43 no.2
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    • pp.123-131
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    • 2010
  • This study was performed to examine the combined effects of gamma linolenic acid and isoflavone supplementation on menopausal symptoms and serum lipids in 73 postmenopausal women. A total subjects were randomly assigned to isoflavone (30 mg) + gamma-linolenic acid (110 mg) group or placebo group. We measured menopausal symptoms by modified Kupperman Index (KI) and oxidized LDL, lipid peroxides, blood components and anthropometric parameters before and after the 12 week intervention period. After the 12 weeks of supplementation, supplement group and placebo group showed a significant reduction of modified kupperman index (p < 0.001). Isoflavone (30 mg) + gamma-linolenic acid (110 mg) supplement group showed a significant reduction of oxidized LDL cholesterol concentration (p = 0.006) whereas placebo group did not show significant change. Isoflavone and gamma-linolenic acid consumption did not significantly affect plasma concentrations of total, LDL, HDL cholesterol, triglyceride, apo A1, B and blood components. The result of present study demonstrated the supplementation of 30 mg isoflavone and 110 mg gamma-linolenic acid per day for 12 weeks may protect LDL cholesterol from oxidative stress.

Pituitary Adenylate Cyclase-activating Polypeptide (PACAP) Treatment during Pre-maturation Increases the Maturation of Porcine Oocytes Derived from Small Follicles

  • Park, Kyu-Mi;So, Kyoung-Ha;Hyun, Sang-Hwan
    • Journal of Embryo Transfer
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    • v.33 no.1
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    • pp.1-11
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    • 2018
  • Cellular cyclic adenosine-3' 5'-monophosphate (cAMP) modulator is known as meiotic inhibitor and can delays spontaneous maturation in IVM experiment. Among many cAMP modulators, the role of Pituitary adenylate cyclase activating polypeptide (PACAP) on IVM isn't known. The purpose of this study is to improve the maturation of oocytes derived from follicles ${\leq}3mm$ in diameter through PACAP as meiotic inhibitor during pre-in vitro maturation (pre-IVM). First, we checked PACAP and its receptors in cumulus cells and, to establish the optimal phase and concentration of PACAP for pre-IVM, we conducted chromatin configuration assessments. As a result, the rate of GV (Germinal Vesicle) according to duration of pre-IVM was significantly decreased 12 h and 18 h after IVM (87.1 and 84.1%, respectively) compared to 0 h (99.4%). When COC was cultured for 18 h, the GV rate in the $1{\mu}M$ of PACAP treatment group (82.1%) was significantly higher than any other PACAP treatment groups (60.5, 64.1, 74.4 and 69.9 %, respectively). So, we divided into four groups as follows; MF (the conventional IVM group, obtained from follicle from 3 to 6 mm in diameter), SF (the conventional IVM group, obtained from follicle ${\leq}3mm$ in diameter), Pre-SF(-)PACAP (IVM group including 18 h pre-IVM without $1{\mu}M$ of PACAP, obtained from follicle ${\leq}3mm$ in diameter) and Pre-SF(+)PACAP (IVM group including 18 h pre-IVM with $1{\mu}M$ of PACAP, obtained from follicle ${\leq}3mm$ in diameter). To examine the effect of PACAP during pre-IVM, we investigated analysis of nuclear maturation, intracellular glutathione (GSH) and reactive oxygen species (ROS) levels. In cumulus cells, PACAP receptors, ADCYAP1R1 and VIPR1 were detected but were not detected in oocytes. After IVM, the Pre-SF(+)PACAP had the highest Metaphase II rate (91.7%) among all groups (P<0.05). The GSH levels in the MF and Pre-SF(+)PACAP were significantly higher than in the other groups (P<0.05) and ROS levels was no significant difference among all groups. In conclusion, these results indicated that even though the oocytes were derived from SF, pre-IVM application of PACAP improved meiotic and cytoplasmic maturation by regulating intracellular oxidative stress.

A Study of Thermo-Mechanical Analysis for the Design of High Pressure Piping System for Natural Gas Fuel Vessel (천연가스 연료선박의 고압 이중 배관 설계를 위한 열-구조 해석에 관한 연구)

  • Park, Seong-Bo;Sim, Myung-Ji;Kim, Myung-Soo;Kim, Jeong-Hyeon;Lee, Jae-Myung
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.4
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    • pp.425-431
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    • 2015
  • LNG (liquefied natural gas) is considered the best alternative eco-fuel, and many studies on the LNG fuel system have been performed to use LNG as the fuel for ships. For the LNG fuel supply system, natural gas transfers from the vaporizer to the engine in the gaseous state with a temperature of $50^{\circ}C$ and a pressure of 35MPa. Therefore, a structural safety evaluation of the double-walled pipelines considering thermal load is essential. In this article, an uniaxial tensile test for super duplex stainless steel, material for double-walled pipe, according to the annealing time was carried out to analyze the thermal effect. In addition, thermo-structural analysis of the high temperature-high pressure double-walled pipe with fixed supports that are now used widely was carried out to evaluate the structural safety. To minimize stress concentration of the connection point between the support and inner pipe, the shapes of the new type support that can slip through inner pipe were proposed, and the supports which has best structural performance was selected using the results from the thermo-structural analyses of new supports and an analysis of the whole double-walled pipeline was performed to ensure structural safety. These results can be used as a database for the design of double-walled pipelines and sliding support.

20S-Protopanaxadiol, an aglycosylated ginsenoside metabolite, induces hepatic stellate cell apoptosis through liver kinase B1-AMP-activated protein kinase activation

  • Park, Sang Mi;Jung, Eun Hye;Kim, Jae Kwang;Jegal, Kyung Hwan;Park, Chung A;Cho, Il Je;Kim, Sang Chan
    • Journal of Ginseng Research
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    • v.41 no.3
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    • pp.392-402
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    • 2017
  • Background: Previously, we reported that Korean Red Ginseng inhibited liver fibrosis in mice and reduced the expressions of fibrogenic genes in hepatic stellate cells (HSCs). The present study was undertaken to identify the major ginsenoside responsible for reducing the numbers of HSCs and the underlying mechanism involved. Methods: Using LX-2 cells (a human immortalized HSC line) and primary activated HSCs, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) assays were conducted to examine the cytotoxic effects of ginsenosides. $H_2O_2$ productions, glutathione contents, lactate dehydrogenase activities, mitochondrial membrane permeabilities, apoptotic cell subpopulations, caspase-3/-7 activities, transferase dUTP nick end labeling (TUNEL) staining, and immunoblot analysis were performed to elucidate the molecular mechanism responsible for ginsenoside-mediated cytotoxicity. Involvement of the AMP-activated protein kinase (AMPK)-related signaling pathway was examined using a chemical inhibitor and small interfering RNA (siRNA) transfection. Results and conclusion: Of the 11 ginsenosides tested, 20S-protopanaxadiol (PPD) showed the most potent cytotoxic activity in both LX-2 cells and primary activated HSCs. Oxidative stress-mediated apoptosis induced by 20S-PPD was blocked by N-acetyl-$\text\tiny L$-cysteine pretreatment. In addition, 20S-PPD concentration-dependently increased the phosphorylation of AMPK, and compound C prevented 20S-PPD-induced cytotoxicity and mitochondrial dysfunction. Moreover, 20S-PPD increased the phosphorylation of liver kinase B1 (LKB1), an upstream kinase of AMPK. Likewise, transfection of LX-2 cells with LKB1 siRNA reduced the cytotoxic effect of 20S-PPD. Thus, 20S-PPD appears to induce HSC apoptosis by activating LKB1-AMPK and to be a therapeutic candidate for the prevention or treatment of liver fibrosis.