• Title/Summary/Keyword: Stress Concentration Ratio

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Preparation and Antioxidant Activities of High Fischer's Ratio Oligopeptides from Goat Whey

  • Qin, Yusi;Cheng, Ming;Fan, Xiaoxue;Shao, Xiaoqing;Wang, Cunfang;Jiang, Hua;Zhang, Xiaoning
    • Food Science of Animal Resources
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    • v.42 no.5
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    • pp.800-815
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    • 2022
  • This study aimed to obtain high Fischer's ratio oligopeptides from goat whey (HFO) and investigate antioxidant property of it. Hydrolysis of goat whey was done with the approach of sequential digestion of pepsin and flavourzyme. With the adsorption of aromatic amino acids by activated carbon, HFO with a Fischer's ratio of 27.070 and a molecular weight of 200-1,000 Da were obtained, and the branched-chain amino acids accounted for 22.87%. Then the antioxidant activity of HFO was evaluated. At the concentrations of 2.0 mg/mL and 0.50 mg/mL, HFO scavenged 77.27% and 99.63% of 1,1-diphenyl-2-picrylhydrazyl and 3-ethylbenzthiazoline-6-sulphonate free radicals respectively. The scavenging rate of HFO against hydroxyl radicals reached 92.31% at the concentration of 0.25 mg/mL. Animal experiments demonstrated that HFO could moderate the changes of malondialdehyde, superoxide dismutase and glutathione peroxidase caused by CCl4-induced oxidative stress in vivo. This study indicated that HFO from goat whey was capable of oxidation resistance both in vivo and in vitro, which provided a scientific basis for the high-value processing and application of goat milk whey.

A Preliminary Study on Fatigue Strength of High Toughness Thermoplastic Composite Material AS4/PEEK (고인성 열가소성 복합재료 AS4/PEEK의 피로강도에 관한 기초적 검토)

  • Song, Ji-Ho;Gang, Jae-Yun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.4 s.175
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    • pp.1055-1064
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    • 2000
  • First, various specimen geometries, namely, coupon type, waisted type and dog-bone type, were examined to determine appropriate fatigue specimen of thermoplastic composite material AS4/PEEK and the n, fatigue strength of smooth and notched specimens of AS4/PEEK [-45/0/+45/90]2s was investigated. Fatigue tests were performed under load controlled condition at a stress ratio of 0. 1 at a frequency of 5Hz. Stiffness degradation of specimens with fatigue cycling was monitored using an automated unloading compliance technique. The waisted type specimen is found appropriate for smooth fatigue specimen geometry of AS4/PEEK. As for the effect of stress concentration, it is found that fatigue strength is higher for a 2mm-diameter hole notched specimen than a 5mm-diameter one. Fatigue notch factor decreases with the increase of fatigue life. These results are far different from the trend of fatigue strength of metallic materials. The stiffness variation of smooth specimen was only 4% at maximum until final fracture. On the other hand, the stiffness of hole notched specimen was reduced by 45% at maximum. Notched fatigue strength was compared between thermoplastic composite AS4/PEEK and thermosetting composite Graphite/Epoxy. In long-life fatigue (>104), the AS4/PEEK composite shows superior fatigue strength, but in short-life fatigue, the fatigue strength of the Graphite/Epoxy composite is nearly equal or somewhat higher than that of the AS4/PEEK composite.

Effects of Geosynthetic Reinforcement on Compaction of High Water Content Clay (토목섬유 보강이 고함수비 점성토의 다짐에 미치는 영향)

  • Roh Han Sung
    • Journal of the Korean Geotechnical Society
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    • v.21 no.2
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    • pp.67-84
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    • 2005
  • This research was conducted to evaluate the effectiveness of reinforcement for nearly saturated soft clay compaction. The effectiveness was investigated by roller compaction test using nearly saturated clay specimens. The nearly saturated condition was obtained by submerging clay in the water for 12 hours. High water content specimens were compacted in plane strain condition by a steel roller. A specimen was compacted by four 5 cm horizontal layers. Specimens were prepared fur both reinforced and unreinforced cases to evaluate the effectiveness of reinforcement. Used reinforcement is a composite consisted of both woven and non-woven geotextile. The composite usually provides drainage and tensile reinforcement to hi인 water-contented clay so that it increases bearing capacity. Therefore, large compaction load can be applied to reinforced clay and it achieves higher density effectively. The reinforcement also increases compaction efficiency because it reduces the ratio between shear and vertical forces during compaction process. The maximum vertical stress on the base of specimen usually decreased with higher compaction thickness. The reinforcement increases soil stiffness under the compaction roller and it initiates stress concentration. As a result, it maintains higher vertical stress level on the base of specimen that provides better compaction characteristics. Based on test results, it can be concluded that the reinforcement is essential to achieve effective compaction on soft clay.

Bezafibrate prevents aging in in vitro-matured porcine oocytes

  • Kim, Ju-Yeon;Zhou, Dongjie;Cui, Xiang-Shun
    • Journal of Animal Science and Technology
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    • v.63 no.4
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    • pp.766-777
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    • 2021
  • Bezafibrate, a fibrate drug used as a lipid-lowering agent to treat hyperlipidemia, is a pan-agonist of peroxisome proliferator-activated receptor alpha. It can enhance mitochondrial fatty acid oxidation, oxidative phosphorylation, and mitochondrial biogenesis. After ovulation, oocytes may get arrested at the metaphase II (MII) stage until fertilization beyond optimal timing, which is termed as post-ovulatory aging. Post-ovulatory aging is a disease that degrades DNA, mitochondria, and oxidative system, and has a negative impact on embryo development and quality; however, the impact of bezafibrate during post-ovulatory aging has not been fully defined. In the present study, we assessed the ability of bezafibrate to prevent the progression of aging in in vitro conditions as well as the underlying mechanisms in pigs. An appropriate concentration of this drug (50 µM) was added, and then oxidative stress, reactive oxygen species downstream, mitochondrial biogenesis, and mitochondrial function were analyzed via immunofluorescence staining and real-time polymerase chain reaction. Bezafibrate significantly alleviated reactive oxygen species and ameliorated glutathione production simultaneously in oocytes and embryos. Moreover, it diminished H2A.X and attenuated CASPASE 3 expression produced by oxidative stress in oocytes and embryos. Furthermore, bezafibrate remarkably improved the mitochondrial function and blastocyst quality as well as markedly reduced the mitochondria/TOM20 ratio and mtDNA copy number. The elevated PARKIN level indicated that mitophagy was induced by bezafibrate treatment after post-ovulatory aging. Collectively, these results suggest that bezafibrate beneficially affects against porcine post-ovulatory oocyte aging in porcine by its antioxidant property and mitochondrial protection.

Effect of Dendropanax morbifera Pharmacopuncture on Sleep-related Hormones, Cognition in Psychosocial Stress-induced Rats (황칠(黃漆) 약침이 정신 스트레스를 받은 백서의 수면 관련 호르몬, 인지에 미치는 영향)

  • Cho, Yun-Song;Lee, Yu-Mi;Na, Chang-Su;Lim, Jung-Hwa;Kim, Bo-Kyung
    • Journal of Oriental Neuropsychiatry
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    • v.30 no.4
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    • pp.341-355
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    • 2019
  • Objectives: The purpose of this study was to check the therapeutic effect of the Dendropanax morbifera Pharmacopuncture for insomnia and cognition caused by psychosocial stress. Methods: We separated Wistar rats (older than age 10 weeks, 300 g) into normal, control, positive control (Zolpidem administered, PC), and Dendropanax morbifera Pharmacopuncture experimental groups (DPA). Psychosocial stress such as circadian rhythm change, clammy straw, predator stress, restraint stress, noise bursts, and flashing lights were applied to the control, PC, DPA groups. The Dendropanax morbifera Pharmacopuncture group was given 0.5×, 1× and 2× amount concentration of Dendropanax morbifera Pharmacopuncture, respectively. The levels of Melatonin, Serotonin, Corticosterone, GABA, BDNF and CREB were measured, and the Y-maze test, weight and blood test were performed. Results: In all of the DPA groups, the Melatonin level showed no noticeable difference. In the DPA-2x group, Serotonin increased significantly. In all the experimental groups, Corticosterone decreased significantly and GABA showed increasing tendency. The DPA-1x and DPA-2x groups showed remarkable increase in BDNF and DPA-0.5x and the DPA-2x groups showed significant increase in CREB. The DPA-2x group showed remarkable increase in the Alternation behavior category of the Y-maze test. In all of the experimental groups the weight change showed increasing tendency, whereas no noticeable differences were found among all experimental groups regarding AST, ALT, BUN, Creatinine and CBC. Conclusions: Dendropanax morbifera Pharmacopuncture increases levels of serotonin and GABA, decreases corticosterone, increases levels of BDNF and CREB, and increases the ratio of alternation behavior in the Y-maze test. Thus, I suggest that Dendropanax morbifera Pharmacopuncture has the effect of treating insomnia caused by psychosocial stress, activating the brain, and improving cognition.

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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Enhancement of performance and anti-oxidant variables in broiler chicken fed diets containing sub-optimal methionine level with graded concentrations of sulphur and folic acid

  • Savaram, Venkata Rama Rao;Mantena, Venkata Lakshmi Narasimha Raju;Paul, Shyam Sunder;Devanaboyina, Nagalakshmi;Thota, Srilatha;Bhukya, Prakash;Ullengala, Rajkumar
    • Animal Bioscience
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    • v.35 no.5
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    • pp.721-729
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    • 2022
  • Objective: An experiment was conducted to determine the effects of supplementing graded concentrations of inorganic sulphur (S) without and with folic acid (FA) in maize-soybean meal diets on performance, slaughter and anti-oxidant variables, immune responses and serum protein fractions in broiler chicken. Methods: Inorganic S was supplemented at 0.05%, 0.10%, 0.15%, and 0.20% alone or in combination with FA (4 mg/kg) in basal diet (BD) containing no supplemental methionine (Met) and FA. A control group was fed with the recommended concentration of Met. Each diet was offered to 10 pens of 5 male broiler chicks (Cobb 400) and fed ad libitum from day 1 to 42. Results: The broilers fed the BD had lower body weight gain (BWG), feed efficiency (FE), higher lipid peroxidation (LP), lower activity of glutathione peroxidase (GSHPx), lower lymphocyte proliferation ratio (LPR), and reduced concentrations of total protein, albumin, and globulin in serum. Supplementation of FA and S to the BD improved the BWG (all concentrations of S) and FE (0.20% S) similar to the control group. Similarly, the combination of S and FA significantly improved the concentrations of total protein, albumin, and globulin in serum, reduced the LP and increased the activity of GSHPx and LPR. However, responses in the above parameters were related to the concentration of S in the diet. The slaughter variables and antibody titres against the Newcastle disease were not affected with the treatments. Conclusion: Based on the results, it is concluded that the combination of S (0.2%) and FA (4 mg/kg) improved the BWG and FE, similarly supplementation of these nutrients improved the concentration of protein fractions and reduced the stress (reduced LP and improved GSHPx) variables in serum and improved the cell mediated immune response (LPR) in broilers fed sub-optimal concentrations of Met in diet.

Effect of stress during slaughter on carcass characteristics and meat quality in tropical beef cattle

  • Carrasco-Garcia, Apolo A.;Pardio-Sedas, Violeta T.;Leon-Banda, Gloria G.;Ahuja-Aguirre, Concepcion;Paredes-Ramos, Pedro;Hernandez-Cruz, Bertha C.;Murillo, Vicente Vega
    • Asian-Australasian Journal of Animal Sciences
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    • v.33 no.10
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    • pp.1656-1665
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    • 2020
  • Objective: This study aimed to determine the effects of stress during slaughter of beef cattle on physiological parameters, carcass, and meat quality at a Federal Inspection Type slaughterhouse located in the southeast of Mexico. Methods: A total of 448 carcasses of male Zebu×European steers with an average age of 36 months were included. Carcass assessment of presence of bruises and bruise characteristics was carried out on each half-carcass. Blood variable indicators of stress (packed cell volume, neutrophil to lymphocyte ratio, glucose, cortisol concentration) and meat quality parameters (pH, color, shear force, drip loss) were evaluated. Results: Of the 448 carcasses evaluated, 81% of the carcasses showed at least one bruise; one bruise was detected in 36.6% and two bruises in 27.0% of animals. Of the 775 bruises found, 69.2% of the bruises were grade 1 in region 3. Of the 448 carcasses studied, 69.6% showed hyperglycemia (6.91 mmol/L); 44.3% and 22.7% showed high (74.7 ng/mL) and extremely high (108.8 ng/mL) cortisol levels, respectively, indicative of inadequate handling of animals during preslaughter and slaughter. Of the carcasses evaluated, 90.4% had a pH ≥5.8 with an average of pH 6.3. In both pH groups, meat samples showed L values >37.0 (81.6%) and a shear force >54.3 N; meat pH≥5.8 group showed a drip loss of 2.5%. These findings were indicative of dark, firm, and dry (DFD) meat. According to principal component analysis, grades 1 and 2 bruises in region 3 and grade 1 bruises in region 5 were highly associated with cortisol, drip loss, and color parameters b and h and were negatively associated with L, a, and C. Conclusion: The bruises probably caused by stress-inducing situations triggered DFD meat. Appropriate changes in handling routines in operating conditions should be made to minimize stress to animals during the slaughter process to improve animal welfare and meat quality.

An Experimental Study on the Engineering Characteristics of Perforated Reinforced Concrete Beams containing Shells (패각을 사용한 철근콘크리트 유공보의 공학적 특성에 관한 연구)

  • Koo, Hae-Shik
    • KIEAE Journal
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    • v.15 no.1
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    • pp.139-146
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    • 2015
  • This is an experimental study on the engineering characteristics of perforated reinforced concrete beams with shells. In the material matter of this study, the water cement ratio put 60%, the ratio of substitution of oyster shells to fine aggregate 30%. And in the structural matter, the form of opening put circle and square, the size of opening as the radius and the length of it changed from one to three times of the beam depth with a change presence and absence of reinforced steel around opening. All thirteen reinforced concrete beam tests composed one standard beam and twelve six beams with the circle and square opening were tested in shear strength under two points loading and compared and analyzed the characteristics of test beams under the same conditions one another. The results of the study showed as followed. 1) The initial crack load value of the opening test beams is similar the standard beam but the maximum load value decreased with increase in proportion of the opening size, in the square opening than the circle opening and in the absence than the presence of reinforced steel. 2) As the difference between the circle opening and the square opening beams is represented 2.17~9.8% in the maximum load value and the load capacity of the square opening suddenly decrease than it of the circle opening, it is judged because of the shortage of concrete section, the concentration of the stress in the corner of the square opening and material influence of shell substitution. 3) The failure figure such as the pattern of the crack and so on is represented brittle failure as the opening size is the bigger and the ratio of substitution is higher because of the lack material properties.

Undrained Characteristics of Geogrid-Encased Stone Column under Cyclic Load Using Reduced-Scale Model Tests (축소모형실험에 의한 반복하중 작용시 지오그리드 감쌈 쇄석말뚝의 비배수 거동 특성)

  • Choi, Jin-Wook;Lee, Dae-Young;Yoo, Chung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.29 no.1
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    • pp.109-120
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    • 2013
  • This paper presents the results of a laboratory investigation into a study on undrained characteristics of a geogrid-encased stone column (GESC) installed in soft clay under cyclic load. In order to analyze behavior of settlement, pore water pressure, stress concentration ratio and strain of the GESC compared to a stone column, a series of reduced-scale laboratory tests were performed. The model tests show that GESC provides a simple and effective method of deformation resistance and settlement restraint when a short-term cyclic load is applied. The maximum strain of geogrid occurred at 1.2D and 1.5D from the top of the column. This paper highlights the importance of considering overlay effect and replacement ratio on cyclic load supporting GESC.