• Title/Summary/Keyword: 구속 스트레스

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Long-Term Torsional Analysis of Prestressed Concrete Members with the Effects of Creep and Shrinkage (크리이프 및 건조수축의 영향을 고려한 프리스트레스트콘크리트 부재의 장기 비틀림 해석)

  • Oh, Byung Hwan;Park, Chang Kyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.4
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    • pp.741-749
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    • 1994
  • The purpose of the present study is to propose a realistic method to analyze the prestressed concrete members subjected to long term torsional loading. The present study devises a method to realistically take into account the tensile stiffness of concrete after cracking. The effects of biaxial compressive and tensile loadings on the compressive and tensile strengths of concrete are also taken into account in the present model. The salient feature of the present study lies in the fact that the cracking, creep, and shrinkage behavior of concrete and the relaxation of steel have been realistically considered. The comparison of the present theory with experimental data indicates that the proposed model dipicts reasonably well the actual behavior of prestressed concrete members under long-term torsional loadings.

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Study on the Change of Catecholamine, Arginine Vasopressin and V1 Vasopressin Receptor Release in the Stressed Rat Brain

  • Kim, Tae-Gyun;Kim, Jee-Hee;Kim, Seung-Hee;Kang, Seog-Youn;Ki, Kyung-Chung;Huh, Young-Buhm;Lee, Song-Deuk
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1997.04a
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    • pp.85-85
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    • 1997
  • 스트레스가 유발된 랫드의 대뇌에서 Vasopressin-catecholamine pathway의 활성도를 알아보기 위해 면역화학염색법으로 vasopressin 호르몬의 분비와 catecholamine의 생성변화를 tyrosine hydroxylase (TH) 효소의 발현변화로 규명하고, arginine vasopressin (AVP)과 V1 vasopressin receptor의 유전자 발현변화를 in situ hybridization 방법을 이용하여 살펴보았다. 수컷 SD rat를 7시간동안 stress cage에 넣어 16$\pm$1$^{\circ}C$의 물에 수침구속 스트레스를 준 후 대조군과 함께 관류고정하여 brain을 적출하였다. Brain의 hypothalamus 부위를 중심으로하여 동결절편하여 면역조직화학 염색과 in situ hybridization을 시행하였다. TH 면역조직화학 염색에서 대뇌의 줄무늬체 부위의 꼬리조가비핵에서와 시상하부 부위의 내측등쪽시상하부와 흑색질부위에서 스트레스군이 대조군에 비해 TH 면역염색성이 증가되어 관찰되었으나 시상하부 부위의 시삭위핵, 뇌실주위핵, 뇌실옆핵에서는 두 군간의 큰 면역염색성의 차이는 보이지 않았다. AVP 면역조직화학 염색에서는 시삭위핵에 많은 수의 AVP 양성 신경세포체들이 밀집되어 있으며 뇌실옆핵에서는 스트레스군에서 AVP 면역염색성이 약간 증가되어 관찰되었으나 신경섬유의 분포양상은 비슷하였다. 중간융기에서는 모두 강한 염색성의 신경섬유들이 관찰되어 두 군간에 큰 차이는 없었다. AVP 유전자에 대한 in situ hybridization 결과 시삭위핵의 신경세포에서 AVP mRNA 양성반응을 관찰할 수 있었으나 다른 시상하부핵에서는 관찰할 수 없었으며, V1 vasopressin receptor에 대한 in situ hybridization 결과는 두 군의 대뇌에서 모두 양성반응을 관찰할 수 없었으며 V1 vasopressin receptor 유전자의 조직별 발현정도와 스트레스에 의한 발현량 조절을 관찰할 필요가 있다고 사료된다.

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Dynamic Behavior of Pretensioned Concrete Member during Detensioning (긴장재 절단에 따른 프리텐션 부재의 동적 거동 고찰)

  • Kim, Jangho;Mun, Do Young;Ji, Goangseup;Kim, Gyuseon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5A
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    • pp.747-756
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    • 2008
  • The purpose of this paper is to investigate the effect of the important parameters on the transfer length during the dynamic flame cutting of tendon experimentally. The considered parameters were strand diameter, concrete cover thickness, stirrup, debonding strand and release method. Ten pretensioned concete beam specimens were cast and tested. Time history curves for the axial strain of tendon were measured by electrical resistance strain gauges mounted on the strands. Experimental results indicated that large dynamic shock effects occurred near cut-end during the sudden release. The prestressing forces are dependent on the parameters above considered. The ratio of residual prestressing forces of 12.7 mm strands is greater than 15.2 mm strands. Using debonding strand and gradual release are more efficient for applying prestressing forces.

The Impact of Family Caregiving for the Elderly with Dementia on Depression in the United States: Does the Relationship of Caregivers to Care Recipients Matter? (미국 치매노인 부양자의 우울증에 영향을 미치는 요소: 배우자 부양자와 딸 부양자 비교 연구)

  • Baek, Ju-Hee;Zarit, Steven H.
    • 한국노년학
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    • v.29 no.4
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    • pp.1591-1609
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    • 2009
  • Adult child caregivers and spousal caregivers might deal with differential challenges. Studies about caregivers' psychological outcomes, however, tended to investigate associations between caregiving and its outcomes by pooling adult child caregivers and spousal caregivers together. By using a U. S. sample of family caregivers who assisted a relative with dementia, this study examined whether the relationship of caregivers to care receivers (daughter caregivers or spousal caregivers) made a difference in levels of depressive symptoms. The result showed that wife caregivers were more likely to be depressed than daughter caregivers. For daughter caregivers, role overload, role captivity, and behavior problems significantly influenced on depression. Besides these variables, the level of education was a significant predictor for wife caregivers. Role captivity and behavior problems significantly impacted on depression for husband caregivers. Thus, role captivity and behavioral problems were common predictors for all the caregivers. Specifically, higher levels of role captivity and behavioral problems were likely to make caregivers more depressed. The implication of these results were discussed.

A Study on Trauma Experiences among Korean Adults based on Conditional probability of PTSD symptoms (PTSD 증상의 조건비율에 근거한 한국 성인의 트라우마 경험에 관한 연구)

  • Kim, Ji-Yun;Lee, Dong-Hun;Kim, Si-Hyeong
    • Korean Journal of Culture and Social Issue
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    • v.24 no.3
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    • pp.365-383
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    • 2018
  • In this study, to search for events that cause high levels of PTSD symptoms, traumatic events are classified into 'criterion events' that meet DSM-IV-TR criteria and 'life stresssful events', conditional probability of PTSD was confirmed. From a sample of 1,000 adults residing in South Korea, 998 statistically relevant samples were extracted. Criterion events include cases of 'sexual harassment before age 16', 'sightings of other accidents', 'rape before 16', 'domestic violence before 16', 'disaster', 'traffic accidents', 'other accidents'. Life stressful events appeared to be 'legal arrest or detention(person and family)', 'parental separation or divorce', 'failure or despair causing serious stress', 'extreme conflict with family or frequent quarrels'. Among the demographic characteristics, age, marital status, religion were found to affect PTSD symptoms. The implications and limitations of these results are discussed.

Experimental Study on Lateral Prestressed Concrete of Spliced Girder using Flexural member Connector (휨연결재를 이용한 횡방향 프리스트레스를 도입한 분절거더의 실험적 성능평가)

  • Kim, Tae-Gyun;Park, Jeong-Cheon;Kim, Jae-Heung;Kim, Sung-Bae;Kim, Jang-Ho Jay
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.13-14
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    • 2010
  • The main purpose of this study is to investigate the static behavior of spliced prestressed concrete girder with bending moment connector and lateral prestressing. Same geometry and materials are used to fabricate these spliced and monolithic girders. A monolithic and spliced specimens materials and dimensions are same. The specimens are comprised of one spliced girder without lateral bending concrete as a control specimen and three spliced girders with lateral bending connectors. Deflections at the middle of girders have been measured for evaluation. Also, strains of the concrete at the middle of span and connection points have been measured.

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The Experimental Study on the Effects of Hyangbujapalmultang on Anti-stress and Immune Response in Immobilization Stressed Rats (향부자팔물탕(香附子八物湯)이 구속(拘束)스트레스 흰쥐의 항(抗)스트레스와 면역반응(免疫反應)에 미치는 영향(影響))

  • Lee Seung-Gi;Kim Jong-Woo;Whang Wei-Wan
    • Journal of Oriental Neuropsychiatry
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    • v.8 no.1
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    • pp.81-93
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    • 1997
  • In order to investigate the anti-stress effect of Hyangbujapalmultnag in immobilization stress rats, the change of body weight, and, the humoral and cellular immune response were measured.The following results were obtained.1. The decrease of the body weight was significantly inhibited in test group, comparing with the control group.2 In the plaque fomation test, the number of the plaque in the control group was decreased but, the decreased in test group was significantly inhibited, comparing with the control group.3. In the hemagglutination titer, the control group was decreased on the serum antibody titer, but, the decreased in test group was significantly inhibited, comparing with the control group.4. In the footpad swelling response, the differences between the control and test group were not shown.

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Anti-stress Effect of Cholic acid Derivatives in Restraint Stress Induced Rats (구속스트레스를 가한 흰쥐에서 Cholate류의 항스트레스 작용에 관한 연구)

  • Park, In;Kim, Yang-Il;Lee, Sun-Mee;Cho, Tai-Soon
    • Biomolecules & Therapeutics
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    • v.4 no.2
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    • pp.162-166
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    • 1996
  • This study was done to investigate whether cholic acid derivatives have anti-stress activity and what is a cause of this anti-stress effect. Seven cholic acid derivatives (cholic acid, taurocholic acid, ursodeoxycholic acid, tauroursodeoxychoic acid, chenodeoxy cholic acid, dehydrocholic acid, hyodeoxycholic acid) were used, silymarin and valproic acid were used as positive controls. Stress was induced by restraint immobilization technique plus water immersion (24hrs) and adrenal weight, spleen weight, adrenal ascorbic acid, serum cholesterol, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), adrenal cholesterol, glucose and corticosterone levels were measured as stress indicators. Most cholic acid derivatives markedly decreased the adrenal weight, and TUDCA and DHCA increased the spleen weight. The restraint stress induced increments in serum LDH, ALP and cholesterol were attenuated by most cholic acid derivatives. Cholic acid, taurocholic acid and tauroursodeoxycholic acid only increased the content of adrenal ascorbate. While valproic acid showed an inhibitory effect against stress, silymarin did not. Our findings suggest that most cholic acid derivatives have anti-stress effect and that their anti-stress effect is, in part, related to choleretic activity.

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Anti-stress Effects of Ursodexycholic Acid on the Restraint Stress in Rats (흰쥐에서 구속스트레스에 대한 우루소데옥시콜린산의 항스트레스 효과)

  • 조태순;이선미;염제호;유은주;임승욱;장병수;김영만;유영효;박명환
    • YAKHAK HOEJI
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    • v.39 no.5
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    • pp.548-553
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    • 1995
  • Effects of restraint stress and its modulations by ursodeoxycholic acid(UDCA) were evaluated on some biochemical and biophysical parameters in rats. Restraint stress induced elevations in blood alkaline phosphatase (ALP). cholesterol (CHOL), aspartate transaminase (GOT), alanine transaminase (GPT), lactate dehydrogenase (LDH) levels. It was also caused adrenal hypertrophy, decrease in weight of spleen and contents of ascorbic acid in stressed rats. As a results, stress indicators such as spleen, ascorbic acid, GOT, GPT, LDH were fastly changed after imposing stress, but those such as ALP, CHOL, adrenal were induced relatively later. UDCA was tested if it has an inhibitory effect against 18-hr restraint induced stress. UDCA lowered ALP, CHOL, LDH level and also effectively elevated the ascorbic acid contents in 25 mg/kg dosage of UDCA. In organ weights. the restraint stress induced increases in spleen and adrenal were attenuated by UDCA in 50 mg/kg dosage. However. stress-induced GOT and GPT levels were unaffected by UDCA.

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Effect of Black Garlic and Mugwort Extracts on Lipids Profile during Restraint Stress (흑마늘과 쑥 추출물이 구속스트레스를 가한 흰쥐의 체내 지질 성분에 미치는 영향)

  • Lee, Soo-Jung;Kang, Min-Jung;Shin, Jung-Hye
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.4
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    • pp.577-586
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    • 2013
  • This study investigated black garlic and mugwort extracts have anti-stress activity. The antioxidant activities of extracts from black garlic (BEP), mugwort (MEP), and three mixtures (MPA, 95:5; MPB, 90:10; MPC, 85:15, w/w% for BEP and MEP, respectively) were tested in vitro. DPPH and ABTS radical scavenging activities for the mixtures (MPA, MPB and MPC) were significantly elevated in a dose-dependent manner by the amount of mugwort extract. A restraint stress was imposed on six groups of Sprague-Dawley rats supplemented with an AIN-93 diet (RSC) or one of five kinds of hot water extract drinks containing (black garlic, RS1; mugwort, RS2; and mixtures of black garlic : mugwort at 95:5, RS3; 90:10, RS4, and a mixture of black garlic : mugwort : apple extract : xylitol=90.25:4.75:2:3, RS5; v/v%) for 4 weeks. The normal group was fed with the AIN-93 diet and not exposed to restraint stress. Food intake was higher in the group fed with garlic extract (RS1), while the body weight gain and food efficiency ratio did not significantly change. The total serum cholesterol content in the RS1 and RS2 groups was significantly lower than the RSC group (control), and the RS5 group was not significantly different compared to the RS3 group. The serum triglyceride content was significantly higher RS3~RS5 groups than RS1 and RS2 groups. In terms of HDL-C and LDL-C contents, AI and CRF in the serum were not significantly different between RS3 and RS5 groups. AST and ALP activities of RS1~RS5 groups were significantly lower than the RSC group. The liver total lipid and cholesterol contents of RS1~RS5 groups were significantly lower than RSC group, and triglyceride content was significantly lower in the RS1 group. Glycogen in the liver tissue was significantly higher in the RS2 and RS3 group compared to the RSC group. These results show that the intake of a mixture of black garlic and mugwort extracts may be effective in the alleviation of hyperlipidemia caused by restraint stress.