Search results for "STRESS"
showing 10 items of 6278 documents
Redox signaling and histone acetylation in acute pancreatitis
2011
Histone acetylation via CBP/p300 coordinates the expression of proinflammatory cytokines in the activation phase of inflammation, particularly through mitogen-activated protein kinases (MAPKs), nuclear factor-κB (NF-κB), and signal transducers and activators of transcription (STAT) pathways. In contrast, histone deacetylases (HDACs) and protein phosphatases are mainly involved in the attenuation phase of inflammation. The role of reactive oxygen species (ROS) in the inflammatory cascade is much more important than expected. Mitochondrial ROS act as signal-transducing molecules that trigger proinflammatory cytokine production via inflammasome-independent and inflammasome-dependent pathways. …
Post-Translational Modifications of Nuclear Proteins in the Response of Plant Cells to Abiotic Stresses
2011
For a long time, in plant cells as in animal cells, the nucleus was only considered as the organelle in which fundamental mechanisms such as replication and transcription occurred. While strong efforts were deployed in order to identify important families of transcription factors such as MYB, WRKY or TGA families (Dubos et al., 2010; Rushton et al., 2010), a few attention was devoted to our lack of knowledge about their regulation in regard to the physiological conditions of the plant cells. Whereas the major importance of posttranslational modification of proteins is well established for several decades regarding cytosolic proteins, the last years have been characterized by the discovery t…
Coping Styles and Social Support in Emergency Workers: Family as a Resource
2015
The nature of the job of people working in emergency situations is such that they may experience high levels of stress. With the term ‘emergency’, we refer to macroscopic events (floods, earthquakes) but also to micro-emergencies, that are more frequent events like accidents and acts of violence. Therefore, the aim of this approach is to help to prevent, or to overcome, the psychic phenomenon that occurs in the victims after a traumatic event that is unexpected and upsetting. In disaster and emergency scenarios, empirical data shows that an effective intervention is able to activate pro-social behaviours, based on social relations and norms; but for emergency workers there are several dange…
Thermoelastic stress analysis of a 2D stress field using a single detector infrared scanner and lock-in filtering
2009
A low resolution, low cost, fast infrared scanner is used to acquire the temperature change along a line on the surface of cyclically loaded samples. The temperature signal is sampled versus time by exploiting the raster scanning movement of the thermocamera single detector. The temperature data is then post-processed by a Fast Fourier Transform based lock- in algorithm implemented in MATLAB ® , in order to filter out the thermoelastic effect induced temperature change. A procedure is also implemented in order to extend the data sampling time by opportunely synchronising successively grabbed data frames. The effectiveness of such synchronisation procedure is first demonstrated by performing…
In search of a theoretical framework of factors influencing work and life balance
2021
Work and life balance (WLB) has gained noticeable attention amid the pandemic. Even before the outbreak of COVID-19, the increasing pace of life encouraged the investigation of individual and organisational aspects of WLB. Physically and mentally healthy people help society develop and grow. Health issues caused by work and life imbalance lead to dissatisfaction with both work and life, which, in turn, leads to higher stress and stress-related illnesses, for instance, burnout. From the organisational point of view, WLB is a factor in analysing the efficiency of an enterprise. The consequences of a work-life imbalance are intentional or unintentional absence, high employee turnover, low prod…
A new calculation procedure for non-uniform residual stress analysis by the hole-drilling method
1998
The hole-drilling method is one of the most used semi-destructive techniques for residual stress analysis in mechanical parts. In the presence of non-uniform residual stress, the stress field can be determined from the measured relaxed strains using several calculation methods, but the most used one is the so-called integral method. This method is characterized by some simplifications that lead to approximate results, especially when the residual stress varies abruptly. In this paper a new calculation procedure called the spline methods is proposed, which allows these drawbacks to be overcome. Numerical simulations and an experimental test have corroborated the best performance of the prop…
Measurement of residual stresses by the hole-drilling method: Influence of hole eccentricity
1979
The hole-drilling method is a semidestructive technique which allows the measurement of residual stresses. In this method, a source of error is due to the misalignment between the hole and rosette centres. This paper presents a theoretical analysis of the influence of such misalignment on the strains measured by the rosette. Formulae which give the residual stresses taking account of the hole eccentricity are derived. Finally, the errors, which affect the residual stresses when the eccentricity is neglected, are evaluated for some commercial strain-gauge rosettes especially developed for the hole-drilling method.
Error and Uncertainty Analysis of the Residual Stresses Computed by Using the Hole Drilling Method
2010
: The hole-drilling method is one of the most used techniques for the experimental analysis of the residual stresses in mechanical components. For both through-thickness uniform and non-uniform residual stress distributions, its application is standardised by the ASTM E837-08. In accordance with the ASTM limitations, the analysis of uniform residual stresses, to which the present work deals with, leads in general to results with a maximum bias of about 10%. Unfortunately, in general the user does not have appropriate procedures to estimate the actual stress error; consequently, if one or more of the experimental influence parameters fall out of the corresponding standard limitations, the c…
A New Procedure for the Evaluation of Non-Uniform Residual Stresses by the Hole Drilling Method Based on the Newton-Raphson Technique
2010
The hole drilling method is one of the most used semi-destructive techniques for the analysis of residual stresses in mechanical components. The non-uniform stresses are evaluated by solving an integral equation in which the strains relieved by drilling a hole are introduced. In this paper a new calculation procedure, based on the Newton-Raphson method for the determination of zeroes of functions, is presented. This technique allows the user to introduce complex and effective forms of stress functions for the solution of the problem. All the relationships needed for the evaluation of the stresses are obtained in explicit form, eliminating the need to use additional mathematical tools. The t…
Review of Some Development of the Hole Drilling Method
1990
This paper contains a survey of some developments of the hole drilling method. It is mainly based on the research work carried out at the University of Palermo in the years from 1978 to 1989. The paper considers the relationship between the relaxed strain and the residual stresses for a rosette with an off-centre hole, the influence of hole eccentricity on the determination of residual stresses and of rosette calibration constants, the sensitivity of strain relaxation.