Exposure to environmental stress

Many engineering thermoplastics (e.g., polysulfone, polycarbonate, etc.) have limited utility in applications that require exposure to chemical environments. Environmental stress cracking [13] occurs when a stressed polymer is exposed to solvents. Poly(aryl ether phenylquin-oxalines) [27] and poly(aryl ether benzoxazoles) [60] show poor resistance to environmental stress cracking in the presence of acetone, chloroform, etc. This is expected because these structures are amorphous, and there is no crystallinity or liquid crystalline type structure to give solvent resistance. Thus, these materials may have limited utility in processes or applications that require multiple solvent coatings or exposures, whereas acetylene terminated polyaryl ethers [13] exhibit excellent processability, high adhesive properties, and good resistance to hydraulic fluid. 

In addition to the function of the ASM in receptor-triggered and developmental apoptosis, the enzyme has a central function in the cellular response to environmental stress stimuli. This review will focus on the examples of ischemia, ultraviolet (UV) light exposure and, in particular, y-irradiation. 

When a plastic exposed to air is subjected to a stress or a strain below its yield point, cracking can occur after a very long duration. The simultaneous exposure to a chemical environment under the same stress or strain can lead to a spectacular reduction of the failure time. The accelerated cracking in this way corresponds to environmental stress cracking (ESC). 

Polycarbonates are handicapped by their sensitivities to light and hydrolysis, requiring efficient protection for outdoor exposure fire behaviour, except for FR grades sensitivity to environmental stress cracking and attacks by chemicals such as bases, oils, chlorinated solvents, ketones. The cost, which is justified by the performances, is higher than that of PMMA and, of course, the commodities. 

Polysulfones are handicapped by their light and UV sensitivity, requiring efficient protection for outdoor exposure sensitivity to environmental stress cracking and attack by chemicals such as aromatic hydrocarbons, chlorinated solvents and ketones the cost, justified by the performances a sometimes insufficient fire resistance, but special grades are marketed. Trade name examples Acudel, Mindel... 

PTSD is attributable to an unusual experience that would be very stressful for almost anyone (e.g., serious threat to life or physical integrity or involvement of the person or a loved one in a major catastrophe, such as a serious traffic accident) (265). This largely environmental-induced disorder has been frequently observed in combat veterans with a history of exposure to overwhelming stress (266). The patient re-experiences the traumatic event by... 

Environmental aging is usually less severe in service (laboratory tests tend to accelerate aging so that the testing can be completed in a reasonable time). However, the effects of the actual service environment are generally more complex. For example, there may be simultaneous exposure to cyclic stress, cyclic temperature, and humid environments. 

Forbes V.E. (1991) Response of Hydrobia ventrosa (Montagu) to environmental stress effects of salinity fluctuations and cadmium exposure on growth. Functional Ecology 5(5) 642-648. 

OEHHA Office of Environmental Health Hazard Assessment OSHA Occnpational Safety and Health Administration Osteogenic sarcoma Cancer associated with bone structures Oxidation Chemical addition of oxygen to break down pollutants or organic waste, for example, destruction of chemical substances such as cyanides, phenols, and organic sulfur compounds in sewage by bacterial and chemical means Oxidative stress Process whereby the metabolic balance of a cell is disrupted by exposure to environmental substances, resulting in accumulation of free radicals, which can damage the cell... 

Trosko JE (1998) Hierarchical and cybernetic nature of biological systems and their relevance to homeostatic adaptation to low-level exposures to oxidative stress-inducing agents. Environmental Health Perspectives 106 331-339. 

HSPs as cellular markers of stress HSPs are involved in various aspects of cellular function and a lot is being learnt about its role in normal and pathological states. Recent studies from lower animals, especially fish, have revealed the potential use of induced fish HSPs as a biomarker of exposure to environmental stressors. Industrial effluents, polycyclic aromatic hydrocarbons, metals such as copper, zinc, mercury, pesticides, etc. have shown to induce HSP in fish. Further, the HSP response may vary with the stressor, tissue, species of fish, and the family of HSP studied. Hence it appears that a more extensive and probably a high-throughput profiling (using genomic and pro-teomic) approaches may be necessary to identify patterns of HSP modulation by various stressors. 

Several stress responses to exposure to environmental contaminants have been studied and are exemplified by the SOS response (Quillardet et al., 1989 Sassanfar et al., 1990 Kenyon et al., 1998), the heat-shock response (Demple and Harrison, 1994 Lee et al., 2003), and the oxidative damage response (Hidalgo et al., 1994 Asad et al.,... 

Kwon, Y.M., Park, S.Y., Birkhold, S.G., and Ricke, S.C. 2000. Induction of resistance of Salmonella typhimurium to environmental stresses by exposure to short-chain fatty acids. Journal of Food Science 65 1037-1040. 

The paradigm for the transformation is plain low socioeconomic status (poverty) results in early age of pregnancy, poor prenatal care, and negative effects on fetal development (through exposure to maternal stress and distress, and to alcohol, tobacco, lead, and other environmental neurotoxins), which... 

However, the problem is greater in India as safety procedures and detoxification procedures advocated in developed countries are often not implemented totally. Human exposure to environmental chemicals can arise from inhalation, dermal contact, and ingestion of polluted water or food, especially those containing biomagnified toxic residues. The industrial and economic developments have changed the lifestyle of urban and rural populations considerably. This has also led to increased stress, thereby threatening health in general. 

Ernst, B., Hoeger, S.T., O Brien, E. and Dietrich, D.R. Physiological stress and pathology in European Whitefish (Coregonus lavaretus) induced by subchronic exposure to environmentally relevant densities of Planktothrix rubescens, Aquat Toxicol, 82(1), 15, 2007. 

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