• Title/Summary/Keyword: intrinsic stress

검색결과 190건 처리시간 0.024초

철도교량의 탄성받침 적용방안 (Application of Elastomeric Bearing for Railway Bridge)

  • 강태우;어성욱;김동식;강영식
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2010년도 춘계학술대회 논문집
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    • pp.1697-1702
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    • 2010
  • It has been recognized for decades that the spherical bearing which is sliding on curved surface in the intrinsic behavior is optimized for the railway bridge requiring a large slope deflection. However, the spherical bearing is easily corrosived at the PSC girder bridge which is exposed to the outside so the normal function of bridge bearing is not fulfilled fully. It is common that the corrosion is happened at the operating plate of steel bridge bearing and generally it is necessary to replace the bridge bearing after 20~25 years. Accordingly, It costs multi billion dollars for maintenance each year and the necessity of improvement become a issue. Korea Rail Network Authority(KR) suggested to apply the Elastomeric bearing instead of Spherical bearing through the task of construction site of 2006. But the normal Elastomeric bearing is optimized for the Highway bridge so it needs the special consideration to satisfy each design condition required by railway bridge. As the result of examination of Elastomeric bearing at the railway bridge construction site, the stress is decreased by effective dispersion of earthquakes and the maintenance fee is also decreased.

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Morinda citrifolia (Noni) Alters Oxidative Stress Marker and Antioxidant Activity in Cervical Cancer Cell Lines

  • Gupta, Rakesh Kumar;Singh, Neeta
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권8호
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    • pp.4603-4606
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    • 2013
  • Background: Cervical cancer, the second most common cancer in women, has a high mortality rate. Cisplatin, an antitumor agent, is generally used for its treatment. However, the administration of cisplatin is associated with side effects and intrinsic resistance. Morinda citrifolia (Noni), a natural plant product, has been shown to have antioxidant activities in vitro and in vivo. Materials and Methods: Both HeLa and SiHa cervical cancer cell lines were treated with 10% Noni, 10 mg/dl cisplatin, or a combination of both 10% Noni and 10 mg/dl cisplatin for 24 hours. Post culturing, the cells were pelleted and stored at $-70^{\circ}C$ for malondialdehyde and catalase assays. Results: On treatment with Noni, CP, and their combination, the level of MDA decreased by 0.76 fold, 0.49 fold, and 0.68 fold respectively in HeLa cells; and by 0.93 fold, 0.67 fold, and 0.79 fold respectively in SiHa cells, as compared to their controls; whereas catalase activity increased by 1.61 fold, 0.54 fold, and 2.35 fold, respectively in HeLa cells; and by 0.98 fold, 0.39 fold, and 1.85 fold respectively in SiHa cells. Conclusions: A decrease in level of lipid peroxidation and an increase in catalase activity were observed with Noni by itself and the effect ameliorated changes observed with cisplatin when given in combination.

고점도 다당류생산 미생물의 분리 및 특성 (A Yellow Pigmented Soil Bacterium Producing a Polysaccharide of High Viscosity)

  • 유진영;정동효
    • 한국식품과학회지
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    • 제21권3호
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    • pp.453-459
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    • 1989
  • 산업용 다당류의 개발을 목적으로 고점도의 다당류생산 미생물을 토양으로부터 분리하였다. 본 세균은 동정한 결과 Pseudomonas mendocina로 생각되었다. 본 세균이 생산하는 다당류는 o-acetyl기를 함유한 ${\beta}-glucan$으로 추정되며 구성당으로서는 포도당과 람노오스가 몰비로 2.2 : 1.0 구성으로 되어 있고 수용액은 의가소성 유체이다. 1% 용액은 428mPa.s의 점도를 나타내며 항복치는 8.89Pa이다. 이 용액은 열안정성은 없으며 pH 안정성과 염안정성은 있었다. 유동활성화에너지는 6.57 Kcal 이다.

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지반의 침식특성을 이용한 교각세굴 사례 연구 (A Case Study of Pier Scour Considering Soil Erodibility)

  • 곽기석;정문경;이주형;박재현
    • 한국지반공학회논문집
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    • 제20권3호
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    • pp.67-74
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    • 2004
  • 사례 연구를 통해서 실제 세립토 교량현장에 대해 기존 교량세굴 해석모델들의 적용성을 분석하였다. 하상이 실트질 점토로 구성된 강화 초지대교를 대상교량으로 선정하여 현장조사를 실시하였다. 초음파 센서장비를 이용하여 교각주변의 세굴심을 직접 측정하였으며, 불교란시료를 채취하여 지반공학적 특성을 결정하고, 또한 세굴률 실험을 통해 대상 지반의 유속별 세굴률을 분석하였다. 그 결과를 바탕으로 기존에 제안된 대표적인 교량세굴 해석모델들을 이용하여 주요 교각의 세굴심을 예측하여 실측 세굴심과 비교하였다. 지반의 침식특성을 고려하지 않는 기존의 교량세굴 해석모델들은 모두 3.6∼6.5의 비율로 세굴심을 과대평가하는 경향을 보였으며, SRICOS 방법은 실측세굴심에 비해 1.7배의 합리적인 결과를 보여주었다.

Speech Rhythm and the Three Aspects of Speech Timing: Articulatory, Acoustic and Auditory

  • Yun, Il-Sung
    • 음성과학
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    • 제8권1호
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    • pp.67-76
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    • 2001
  • This study is targeted at introducing the three aspects of speech timing (articulatory, acoustic and auditory) and discussing their strong and weak points in describing speech timing. Traditional (extrinsic) articulatory timing theories exclude timing representation in the speaker's articulatory plan for his utterance, while the (intrinsic) articulatory timing theories headed by Fowler incorporate time into the plan for an utterance. As compared with articulatory timing studies with crucial constraints in data collection, acoustic timing studies can deal with even several hours of speech relatively easily. This enables us to perform suprasegmental timing studies as well as segmental timing studies. On the other hand, perception of speech timing is related to psychology rather than physiology and physics. Therefore, auditory timing studies contribute to enhancing our understanding of speech timing from the psychological point of view. Traditionally, some theories of speech timing (e.g. typology of speech rhythm: stress-timing; syllable-timing or mora-timing) have been based on our perception. However, it is problematic that auditory timing can be subjective despite some validity. Many questions as to speech timing are expected to be answered more objectively. Acoustic and articulatory description of timing will be the method of solving such problems of auditory timing.

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가상 고정물을 이용한 축 대칭 용접물의 용접 변형 해석 모델링 기법 (Modeling Techniques using Virtual Fixture for Analysing the Shrinkage of Axi-symmetric Welded Structures)

  • 이호진;이봉상;정인철;심덕남
    • Journal of Welding and Joining
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    • 제28권2호
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    • pp.60-65
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    • 2010
  • Although two dimensional axi-symmetric modeling is useful for calculating the residual stresses of a cylindrical weldment such as a core barrel, this conventional axi-symmetric modeling can not express the behavior of shrinkage well in the locally heated weld zone. New technique of two dimensional axi-symmetric modeling using a virtual fixture is suggested to simulate the behavior of dimensional changes in the weld zone during the heating period of the welding. The virtual fixture in the model has a role to restrain the expansion of the high temperature heated region, which simulates equivalent intrinsic restraint effect of the weldment. In the restraint condition of the virtual fixture above the critical yield strength, the calculated shrinkages by using the suggested axi-symmetric model agreed well with those measured in a welded mock-up. The calculated residual stresses by using the suggested axi-symmetric model also agreed well with those calculated by using conventional axi-symmetric model which has beenused for calculating residual stresses in the weldment.

Key Success Factors of Home-Based Business among Female Entrepreneur in Saudi Arabia

  • bin Dahari, Zainurin;Abu Bakar, Abdul Rahim;Al-Gosaibi, Sahar
    • Asia Pacific Journal of Business Review
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    • 제3권2호
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    • pp.43-66
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    • 2019
  • Home-based business (HBB) is one of the fastest growing form of business start-ups where the business is conducted from home. In develop economies, the HBB industry is an engine for economic growth that has proven its viability through significant contribution to the national GDP. In view of its importance, the Saudi Ministry of Commerce and Industry encourage local women to start and develop their own HBB as it gives them the flexibility while still contributing to the national economy. Although various initiatives have been taken place, little information is available about Saudi HBB. This study therefore aims to determine the factors that contribute to the growth as well as the challenges of female HBB in Saudi Arabia. The study was based on qualitative approach which adopted an in-depth interview with eleven Saudi females who run HBB. The findings revealed that HBB contributing factors comprised of access to funding, sufficiency of savings and the influence of the intrinsic and extrinsic motivation in starting the business. Meanwhile, the obstacles are government regulations and policies, culture, and home design. The study recommendations include improving banks and service institution policy and procedures to enable HBB to have access to funding and services and to develop legal policies to protect the right of the HBB operator and customers. Finally, the study also suggests future research on managerial factors that can contribute to HBB female success, the stress coping mechanism of HBB and the factors contributing to the difference between HBB in growth strategies.

중환자실 환자의 간호지속성 유지를 위한 중환자실-병동간 연계형 전환간호 프로그램 개발 및 효과 (Development and Effects of the Collaborative Transitional Care Program for Continuity of Care in Patients Transferred to General Wards from ICUs)

  • 손연정
    • 임상간호연구
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    • 제15권3호
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    • pp.143-155
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    • 2009
  • Purpose: This study was conducted to develop and evaluate the collaborate transitional care program for improving continuity of care in patients transferred to general wards from ICUs. Methods: 18 years and older who were hospitalized in adult intensive care units at A university affiliated medical center was recruited for the study. The experimental group for patients transferred from an ICU consisted of 33 patients and family caregivers; 34 patients and family caregivers for the control group. This study was utilized a quasi-experimental research design. The collaborative transitional care program was administered in transfer process. Data were collected two times by interviews, medical records, and telephone using questionnaires. Results: There were statistically significant differences between the two groups on relocation stress (p<.001), perceived health status (p<.001), satisfaction of caring (p=.011), physical domain (p=.022) and mental domain (p<.001) of the QOL. There were significant differences between the families of the two groups on burden (p<.001) and satisfaction of caring (p<.001). Conclusion: The collaborative transitional care programs administered in transfer process to general wards from an ICU have positive effects on patients and families' intrinsic and extrinsic factors. This program will be able to be utilized in clinical fields to improve continuity of care for patients and families between ICUs and general wards.

모래쥐에서 뇌의 허혈/재관류에 의한 산화성 스트레스 형성과 HSP70의 발현 (Oxidative Stress and HSP70 Expression Upon Cerebral Isehemia-Reperfusion in Mongolian Gerbil)

  • 박영미;김철훈;도윤정;최은미;안영수
    • 대한약리학회지
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    • 제32권3호
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    • pp.335-345
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    • 1996
  • 허혈/재관류 뇌손상에서 활성산소류의 역할이 중요시되고 있다. 본 연구에서는 모래쥐의 총경동맥을 묶었다 풀어줌으로써 실험적 허혈/재관류 손상을 유도하고 산화성 스트레스 발생 유무와 이러한 산화성 스트레스가 세포손상으로 연결되는지를 알아보고자 하였다. 해마는 뇌조직 중에서도 특히 산화성 스트레스에 취약한 부분이므로 해마에서 얻은 조직을 대뇌피질에서 얻은 조직과 비교분석하였다. 또한, 이들 부위에서 heat shock protein 70(HSP70)의 발현이 허혈/재관류 손상에 미치는 영향도 검색하고자 하였다. 허혈/재관류에 의한 산화성 스트레스의 지표로써 글루타치온 산화정도, GSSG/(GSH+2xGSSG)를 측정하였을 때 주로 해마에서 산화지표가 상승됨을 관찰하였다. 한편 산화성 스트레스가 세포손상으로 연결되는지를 알아보고자 지질과산화물을 측정하였다. 두 부위 모두에서 지질과산화물 형성의 증가가 있었으며 대뇌피질에서보다 해마에서 더 증가됨을 알 수 있었다. 지질과산화물 형성의 정도나 시간적 변화양상이 글루타치온 산화의 그것들과 유사하였다. 이러한 결과들은 허혈/재관류에 의해 산화성 스트레스가 형성되며 동시에 이러한 산화성 스트레스가 세포 손상을 초래함을 보여준다. 또한 산화성 스트레스 및 산화성 세포손상 정도가 대뇌피질보다는 해마에서 더 큰 것을 알 수 있었다. 그러나, 피질과 해마에서 HSP70의 기초발현(basal level) 정도는 차이가 없었다. 이는 해마의 취약성이 HSP70 발현 결핍에 기인하지 않았음을 나타낸다. 반면 허혈/재관류에 의한 HSP70의 발현유도는 해마조직에서 제대로 이주어지지 않았고 northern blot결과 이는 전사단계에서의 부친에 의한 것으로 나타났다. 이러한 결과들로 볼 때 허혈/재관류에 의한 뇌손상에서 HSP70 유도정도를 측정하는 것이 세포의 취약성을 예측할 수 있는 지표로 유용하게 사용될 수 있을 것으로 사료된다.

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벼 종자에서 액포막 aquaporin (tonoplast intrinsic protein) 유전자의 발현과 기능 (Functional implications of gene expression analysis from rice tonoplast intrinsic proteins during seed germination and development)

  • 허선미;이인숙;김범기;신영섭;이강섭;김둘이;변명옥;김동헌;윤인선
    • Journal of Plant Biotechnology
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    • 제37권4호
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    • pp.517-528
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    • 2010
  • 종자 발달과 발아는 수분과 양분 함량의 급격한 변화를 수반하는 복합적인 과정이다. 본 연구에서는 유전자 발현과 단백질 구조 비교 분석을 통해 벼 종자의 발아와 발달과정에 관여하는 액포막 aquaporin (tonoplast intrinsic protein)을 규명하였다. OsTIP3;1, OsTIP3;2는 종자 특이적인 TIP로 종자가 성숙되는 시기에 발현되었다가, 종자가 발아하면서 전사체가 사라지는 양상을 보였으며, ABA 처리에 의해 발현이 유도되었다. 단백질 구조 예측 결과로부터 OsTIP3;1, OsTIP3;2가 단백질의 N-말단, B와 E loop에 다른 TIP와 뚜렷이 구분되는 인산화 잔기 특징을 확인하였다. OsTIP2;1과 OsTIP4;3은 종자가 발달하는 과정에서 유전자 발현이 감소하였다가, 종자 발아 후기에 뿌리와 배축의 신장이 활발한 시기에 발현이 급증하였다. 특히 OsTIP2;1은 뿌리에서 강한 발현을 보였으므로, 뿌리 생장에 필요한 팽압 공급에 중요한 기능을 할 것으로 제안된다. OsTIP2;1과 OsTIP4;3 단백질의 N-말단에는 특징적으로 메틸화 (methylation) 가능성이 높은 아미노산 잔기가 예측되었다. OsTIP2;2는 OsTIP2;1과는 달리 종자 침윤 후 7시간 이내에 발현이 빠르게 유도되며, 발아가 억제되는 조건에서도 유전자 발현이 유지되는 것으로 보아 종자의 초기 수화 과정에 관여할 것으로 추측된다. OsTIP2;2 단백질의 N-말단에는 OsTIP2;1에 존재하는 인산화 Ser 잔기와 메틸화 잔기가 결실된 특징을 보였다. 이런 결과들은 벼 종자의 발달과 발아 과정에서 나타나는 액포의 종류와 기능에 따라 서로 다른 TIP가 선택적으로 유전자 발현수준에서 조절되며, 인산화, 메틸화 등 단백질 수식에 의한 활성조절 기작 역시 매우 다르다는 것을 시사한다.