• Title/Summary/Keyword: Complex stress

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Coping Strategy Against the Stress -It's Biological Approaches- (스트레스 대응전략 -생물학적 접근-)

  • Chung, Young-Cho
    • Korean Journal of Psychosomatic Medicine
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    • v.3 no.1
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    • pp.72-80
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    • 1995
  • Because the origins of stress are various, complex, and often indirectly-causing, reactions to stress are also various according to it's psychopathologies and mechanisms. For a proper management of stress, first of all accurate evaluation and diagnosis must be done. Then, treatment against the stress also can be considered, if necessary. In case of extreme stress, psychotropic drugs such as short-term anxiolytics or antidepressants can be used according to it's specific target symtoms. But long-term treatment of stress must be directed by increasing the individual's usual coping strategy or decreasing the externally causing stresses. Reactions to stress and drug interactions. which are not the whole of the biologic treatment strategy, are very important As a results, in our discussions, we ought to describe the issues by focusing the interactions between the drug and it's reaction to stress rather than the reaction to stress or drug itself and aimed at helping the proper treatment against the stress.

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AtHAP3b Plays a Crucial Role in the Regulation of Flowering Time in Arabidopsis during Osmotic Stress

  • Chen, Nai-Zhi;Zhang, Xiu-Qing;Wei, Peng-Cheng;Chen, Qi-Jun;Ren, Fei;Chen, Jia;Wang, Xue-Chen
    • BMB Reports
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    • v.40 no.6
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    • pp.1083-1089
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    • 2007
  • The HAP complex has been found in many eukaryotic organisms. HAP recognizes the CCAAT box present in the promoters of 30% of all eukaryotic genes. The HAP complex consists of three subunits - HAP2, HAP3 and HAP5. In this paper, we report the biological function of the AtHAP3b gene that encodes one of the HAP3 subunits in Arabidopsis. Compared with wild-type plants, hap3b-1 and hap3b-2 mutants exhibited a delayed flowering time under long-day photoperiod conditions. Moreover, the transcription levels of FT were substantially lower in the mutants than in the wild-type plants. These results imply that AtHAP3b may function in the control of flowering time by regulating the expression of FT in Arabidopsis. In a subsequent study, AtHAP3b was found to be induced by osmotic stress. Under osmotic stress conditions, the hap3b- 1 and hap3b-2 mutants flowered considerably later than the wild-type plants. These results suggest that the AtHAP3b gene plays more important roles in the control of flowering under osmotic stress in Arabidopsis.

Influence of the Biodegradable Packaging Material on the Rheological Properties of Eggs (생분해성 포장재질이 달걀의 물성에 미치는 영향 연구)

  • Kim, Ji-Hyun;Park, Jong-Shin;Kim, Byung-Yong
    • Applied Biological Chemistry
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    • v.40 no.6
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    • pp.525-530
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    • 1997
  • The changes in rheological properties of egg white stored in biodegradable package were investigated by pH change, failure stress and stress relaxation curve, and compared with control without package and complex PE. Initial pH of egg white stored in biodegradable package changed from 8.39 to 9.3 after 8 day storage, showing similar trend in pH change as that of control without package. Initial 14.25 N failure stress was changed into 6.76 N in biodegradable package and 9.31 N in control. Complex PE, having a relatively low gas permeability compared to biodegradable package, showed less pH changes from 8.30 to 8.81, but a greater decrease in failure stress into 5.29 N, indicating more deteriorating effect in complex PE package. Viscoelastic constants, such as elastic constant and viscous constant, obtained from stress-relaxation curve by three element Maxwell model were not significantly different between control and biodegradable package, but eggs stored in complex PE showed greater changes during storage. Therefore, the permeability seems to be the major factors to influence the rheological properties of egg and biodegradable packaging materials showed a potential substitute package for eggs.

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Comparison of Full-Field Stresses around an Inclined Crack Tip by Using Fringe Data of Finite Element Method with Photoelastic Experiment

  • Baek, Tae-Hyun;Kim, Myung-Soo;Chen, Lei
    • Journal of the Korean Society for Nondestructive Testing
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    • v.29 no.6
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    • pp.557-562
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    • 2009
  • Abrupt change of cross-section in mechanical parts is one of significant causes of structural fracture. In this paper, a hybrid method is employed to analyze the stress distribution of a discontinuous plate. The plate with an inclined crack is utilized in our experiment and the stress field in the vicinity of crack tip is calculated through isochromatic fringe order of given points. This calculation can be made handy through least-squares method integrated with complex power series representation(Laurent series) implemented on a computer program for high-speed processing. In order to accurately compare calculated results with experimental ones, both of actual and regenerated photoelastic fringe patterns are doubled and sharpened by digital image processing. The experiment results show that regenerated patterns obtained by hybrid method are quite comparable to actual patterns.

A Study on Energy Release Rate for Interface Cracks in Pseudo-isotropic Dissimilar Materials (유사등방성 이종재 접합계면 균열의 에너지 해방률에 관한 연구)

  • 이원욱;김진광;조상봉
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.193-200
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    • 2003
  • The energy release rate for an interface crack in pseudo-isotropic dissimilar materials was obtained by the eigenfunction expansion method using the two-term William's type complex stress function. The complex stress function for pseudo-isotropic materials must be different from that for anisotropic materials. The energy release rate for an interface crack in pseudo-isotropic dissimilar materials was analyzed numerically by RWCIM. The results obtained were verified by comparing the other worker's results and discussed.

A study on the eigenvector analyses for V-notched cracks in Anisotropic Dissimilar Materials by the Reciprocal Work Contour Integral Method (상반일 등고선 적분법(RWCIM)을 이용한 이방성 이종재료 내의 V-노치 균열에 대한 고유벡터 해석)

  • Roh, Hong-Rae;Kim, Jin-Kwang;Cho, Sang-Bong
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.115-120
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    • 2000
  • This paper examines that it is possible to apply RWCIM for determining eigenvector coefficients associated with eigenvalues for V-notched cracks in anisotropic dissimilar materials using the complex stress function. To verify the RWCIM algorithm, two tests will be shown. First it is performed to ascertain whether predicted coefficients associated with eigenvectors is obtained exactly. Second, it makes an examination of the state of stress for FEM and RWCIM according to a number of eigenvectors at a location far away from the V-notched crack tip.

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Numerical Simulation of Turbulent Flows Under a Plane Rate of Strain Condition in a Rotating $90^{\circ}$ Curved Duct (평면변형율 조건 하의 회전하는 $90^{\circ}$ 곡덕트 내 난류유동의 전산해석)

  • Kwon, Hyung-Joong;An, Jung-Soo;Choi, Young-Don
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.485-490
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    • 2000
  • The effect of curvature, rotation, variable cross-section can make very complex flow pattern in turbo-machinery such as Pumps, compressors, turbines, In this study of turbulent flow characteristics rotating $90^{\circ}$ curved duct under a Plane rate of strain condition is computationally analyzed. The objective of this study is to understand the complex turbulent flow phenomena in turbo-machinery passage by analyzing the modeled rotating $90^{\circ}$ curved duct flow. RSM(Reynolds Stress Model) was employed for the turbulence modeling of Reynolds stress in momentum equations proposed by Shin(1995). The three dimensional computational code which adopts RSM for trubulence modeling was newly developed for the generalized curvilinear coordinate.

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Stress Intensity Factors for a Crack in a Nonlinear Electrostrictive Material (비선형 전왜재료 내부의 균열에 대한 응력 확대계수)

  • Beom, Hyeon-Gyu;Jeong, Eun-Do
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.2
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    • pp.186-191
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    • 2001
  • A crack with electrically impermeable surfaces in an electrostrictive material subjected to uniform electric loading is analysed. The effect of electric yielding on stress intensity factor is investigated by using a small scale yielding model and a strip yield zone model. Complete forms of electric fields and elastic fields are derived by using complex function theory. The electrical yield zone shapes for two models are different each other. The two models, however, predict similar yield zone sizes under the small scale yielding conditions. It is found that the influence of electric yielding on the stress intensity factor is insensitive to the modeling of the electrical yield zone shape.

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Understanding the Unfolded Protein Response (UPR) Pathway: Insights into Neuropsychiatric Disorders and Therapeutic Potentials

  • Pitna Kim
    • Biomolecules & Therapeutics
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    • v.32 no.2
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    • pp.183-191
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    • 2024
  • The Unfolded Protein Response (UPR) serves as a critical cellular mechanism dedicated to maintaining protein homeostasis, primarily within the endoplasmic reticulum (ER). This pathway diligently responds to a variety of intracellular indicators of ER stress with the objective of reinstating balance by diminishing the accumulation of unfolded proteins, amplifying the ER's folding capacity, and eliminating slow-folding proteins. Prolonged ER stress and UPR irregularities have been linked to a range of neuropsychiatric disorders, including major depressive disorder, bipolar disorder, and schizophrenia. This review offers a comprehensive overview of the UPR pathway, delineating its activation mechanisms and its role in the pathophysiology of neuropsychiatric disorders. It highlights the intricate interplay within the UPR and its profound influence on brain function, synaptic perturbations, and neural developmental processes. Additionally, it explores evolving therapeutic strategies targeting the UPR within the context of these disorders, underscoring the necessity for precision and further research to effective treatments. The research findings presented in this work underscore the promising potential of UPR-focused therapeutic approaches to address the complex landscape of neuropsychiatric disorders, giving rise to optimism for improving outcomes for individuals facing these complex conditions.

Reliability computation technique for ball bearing under the stress-strength model

  • Nayak, S.;Seal, B.
    • International Journal of Reliability and Applications
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    • v.17 no.1
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    • pp.51-63
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    • 2016
  • Stress function of ball bearing is function of multiple stochastic factors and this system is so complex that analytical expression for reliability is difficult to obtain. To address this pressing problem, in this article, we have made an attempt to approximate system reliability of this important item based on reliability bounds under the stress strength setup. This article also provides level of error of this item. Numerical analysis has been adopted to show the closeness between the upper and lower bounds of this item.