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The histone deacetylase Rpd3p is required for transient changes in genomic expression in response to stress
Adriana L Alejandro-Osorio, Dana J Huebert, Dominic T Porcaro, Megan E Sonntag, Songdet Nillasithanukroh, Jessica L Will, Audrey P Gasch
Genome Biology , 2009, DOI: 10.1186/gb-2009-10-5-r57
Abstract: We found that the Rpd3-Large complex is required for proper expression of both induced and repressed Environmental Stress Response genes under multiple stress conditions. Cells lacking RPD3 or the Rpd3-Large subunit PHO23 had a major defect in Environmental Stress Response initiation, particularly during the transient phase of expression immediately after stress exposure. Chromatin-immunoprecipitation showed a direct role for Rpd3-Large at representative genes; however, there were different effects on nucleosome occupancy and histone deacetylation at different promoters. Computational analysis implicated regulators that may act with Rpd3p at Environmental Stress Response genes. We provide genetic and biochemical evidence that Rpd3p is required for binding and action of the stress-activated transcription factor Msn2p, although the contribution of these factors differs for different genes.Our results implicate Rpd3p as an important co-factor in the Environmental Stress Response regulatory network, and suggest the importance of histone modification in producing transient changes in gene expression triggered by stress.Sudden environmental changes can trigger rapid and dramatic changes in genomic expression. This involves coordinated expression of hundreds to thousands of genes, whose expression is precisely modulated in timing and magnitude. Many different transcription factors function in the cell at any given time and respond to distinct upstream signals. Therefore, cells must integrate the action of numerous signals and regulatory factors to produce a coherent genomic expression program customized for each new environment.Yeast respond to stress in part by initiating the Environmental Stress Response (ESR), which consists of approximately 600 genes whose expression is repressed and approximately 300 genes whose expression is induced by diverse stresses [1,2]. The repressed genes include approximately 130 ribosomal protein ('RP') genes and a distinct group of approxim
STRESS RELAXATION BEHAVIOUR OF TITANIUM
XIA Yuebo WANG Zhongguang Institute of Metal Research,Academia Sinica,Shenyang,China Associate Professor,Institute of Metal Research,Academia Sinica,Shenyang,China,
XIA Yuebo WANG Zhongguang Institute of Metal Research
,Academia Sinica,Shenyang,China Associate Professor,Institute of Metal Research,Academia Sinica,Shenyang,China

金属学报(英文版) , 1989,
Abstract: Studies of stress relaxation were carried out on commercially pure titanium.It was found thatthe stress relaxation behaviour relates closely to the level of deformation.The amount of re-laxed stress σ_R is independent of the amplitude of stress dip in a certain range ofdeformation.However,it depend on the stress level at which stress relaxation begins in a cer-tain relaxation time t_R.Both back(critical)stress σ_c and flow stress σ_o vary with the strainin a similar manner.The effective stress on dislocations σ~* increases with increasing strainunder low strains,but keeps constant under higher strains.
Relaxation Response Induces Temporal Transcriptome Changes in Energy Metabolism, Insulin Secretion and Inflammatory Pathways  [PDF]
Manoj K. Bhasin, Jeffery A. Dusek, Bei-Hung Chang, Marie G. Joseph, John W. Denninger, Gregory L. Fricchione, Herbert Benson, Towia A. Libermann
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062817
Abstract: The relaxation response (RR) is the counterpart of the stress response. Millennia-old practices evoking the RR include meditation, yoga and repetitive prayer. Although RR elicitation is an effective therapeutic intervention that counteracts the adverse clinical effects of stress in disorders including hypertension, anxiety, insomnia and aging, the underlying molecular mechanisms that explain these clinical benefits remain undetermined. To assess rapid time-dependent (temporal) genomic changes during one session of RR practice among healthy practitioners with years of RR practice and also in novices before and after 8 weeks of RR training, we measured the transcriptome in peripheral blood prior to, immediately after, and 15 minutes after listening to an RR-eliciting or a health education CD. Both short-term and long-term practitioners evoked significant temporal gene expression changes with greater significance in the latter as compared to novices. RR practice enhanced expression of genes associated with energy metabolism, mitochondrial function, insulin secretion and telomere maintenance, and reduced expression of genes linked to inflammatory response and stress-related pathways. Interactive network analyses of RR-affected pathways identified mitochondrial ATP synthase and insulin (INS) as top upregulated critical molecules (focus hubs) and NF-κB pathway genes as top downregulated focus hubs. Our results for the first time indicate that RR elicitation, particularly after long-term practice, may evoke its downstream health benefits by improving mitochondrial energy production and utilization and thus promoting mitochondrial resiliency through upregulation of ATPase and insulin function. Mitochondrial resiliency might also be promoted by RR-induced downregulation of NF-κB-associated upstream and downstream targets that mitigates stress.
Stress Relaxation in Diblock Copolymers  [PDF]
Adolfo M. Nemirovsky,Thomas A. Witten
Physics , 2001,
Abstract: We study stress relaxation in a strongly segregated lamellar mesophase of diblock copolymers. We consider the extreme limit in which chains are highly stretched and with their junction points confined to narrow interfaces. A lamella can be divided into "stress blobs" at some distance $z$ from the interface, with well defined local modulus $G(z,\omega)$ at frequency $\omega$. For sliding (compressional) stress the total modulus is transmitted in series (parallel) across the layer. We evaluate the local $G(z,t)$ which shows, for a given height, a very broad spectrum of relaxation times.
On the diffusive stress relaxation for multidimensional viscoelasticity  [PDF]
Donatella Donatelli,Corrado Lattanzio
Mathematics , 2006,
Abstract: This paper deals with the rigorous study of the diffusive stress relaxation in the multidimensional system arising in the mathematical modeling of viscoelastic materials. The control of an appropriate high order energy shall lead to the proof of that limit in Sobolev space. It is shown also as the same result can be obtained in terms of relative modulate energies.
Stress Relaxation in Entangled Polymer Melts  [PDF]
Ji Xuan Hou,Carsten Svaneborg,Ralf Everaers,Gary S. Grest
Physics , 2010, DOI: 10.1103/PhysRevLett.105.068301
Abstract: We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, $G(t)$, into the plateau regime for chains with $Z=40$ entanglements and into the terminal relaxation regime for $Z=10$. Using the known (Rouse) mobility of unentangled chains and the melt entanglement length determined via the primitive path analysis of the microscopic topological state of our systems, we have performed parameter -free tests of several different tube models. We find excellent agreement for the Likhtman-McLeish theory using the double reptation approximation for constraint release, if we remove the contribution of high-frequency modes to contour length fluctuations of the primitive chain.
Glass transition theory based on stress relaxation  [PDF]
Kostya Trachenko
Physics , 2005, DOI: 10.1088/0953-8984/18/19/L04
Abstract: We propose that an onset of glass transition can be defined as the point at which a supercooled liquid acquires the stress relaxation mechanism of a solid glass. We translate this condition into the rate equation for local relaxation events. This equation simultaneously gives two main signatures of glass transition, stretched-exponential relaxation and the Vogel-Fulcher law. The proposed theory quantifies system fragility in terms of the number of retarded local relaxation events and reproduces its correlation with the non-exponentiality of relaxation and bonding type.
Immune Modulation in Response to Stress and Relaxation  [PDF]
Mahbub-E-Sobhani,N. Haque,U. Salma,A. Ahmed
Pakistan Journal of Biological Sciences , 2011,
Abstract: Traditional medical science has kept the mind separate from the body. Recently people realize the effect of mind on health and psychoneuroimmunology is the new evolved science that describes the interactions between psyche and soma. In this review through a typical psycho-neuro-endocrino-immune network the effects of psychological stress (acute, brief naturalistic and chronic) and relaxation on immune modulation has been shown. From this network Corticotrophin Releasing Factor (CRF), Adrenocorticotrophic Hormone (ACTH), Glucocorticoids (GC), a-endorphin and Met-enkephalin are found as important endocrine components and T cells, B cells, monocytes/macrophages, Natural Killer (NK) cells and their cytokines that is Tumor Necrosis Factor-a (TNF-a), Interferon Gamma (IFN-a) and interleukins such as IL-1, IL-2, IL-4, IL-6, IL-10, IL-12 etc. are found as important immune components. Finally, it has been shown that, acute, brief naturalistic and chronic stress have different immune modulatory activities which are harmful to ones homeostasis and relaxation can help to maintain that homeostasis.
Overdamped Stress Relaxation in Buckled Rods  [PDF]
Oskar Hallatschek,Erwin Frey,Klaus Kroy
Physics , 2004, DOI: 10.1103/PhysRevE.70.031802
Abstract: We present a comprehensive theoretical analysis of the stress relaxation in a multiply but weakly buckled incompressible rod in a viscous solvent. In the bulk two interesting regimes of generic self--similar intermediate asymptotics are distinguished, which give rise to two classes of approximate and exact power--law solutions, respectively. For the case of open boundary conditions the corresponding non--trivial boundary--layer scenarios are derived by a multiple--scale perturbation (``adiabatic'') method. Our results compare well with -- and provide the theoretical explanation for -- previous results from numerical simulations, and they suggest new directions for further fruitful numerical and experimental investigations.
Granular dynamics in compaction and stress relaxation  [PDF]
Jasna Brujic,Ping Wang,Chaoming Song,David L. Johnson,Olivier Sindt,Hernan A. Makse
Physics , 2005, DOI: 10.1103/PhysRevLett.95.128001
Abstract: Elastic and dissipative properties of granular assemblies under uniaxial compression are studied both experimentally and by numerical simulations. Following a novel compaction procedure at varying oscillatory pressures, the stress response to a step-strain reveals an exponential relaxation followed by a slow logarithmic decay. Simulations indicate that the latter arises from the coupling between damping and collective grain motion predominantly through sliding. We characterize an analogous "glass transition" for packed grains, below which the system shows aging in time-dependent sliding correlation functions.
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