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Stress Sensitivity (stress + sensitivity)
Selected AbstractsInfluence of nanocrystalization on magnetoelastic Villari effect in Fe73.5Nb3Cu1Si13.5B9 alloyCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3-5 2003R. Szewczyk Abstract The results of an investigation of the influence of thermal annealing on the magnetoelastic properties of Fe73.5Nb3Cu1Si13.5B9 soft magnetic alloy in both amorphous and nanocrystalline state are presented. A new method developed was used to apply uniform compressive stresses to the investigated ring core made of the alloy. The compressive stresses produced by external mechanical forces were applied perpendicularly to the direction of the magnetizing field. Due to the uniform distribution of stresses in the core brittle nanocrystalline alloys may be tested for stresses up to 10 MPa. The results revealed, that process of nanocrystallisation causes significant increase in the stress sensitivity of the Fe73.5Nb3Cu1Si13.5B9 alloy. Moreover the influence of stresses caused by external forces is more significant at relatively low values of the magnetizing field suggesting that these nanocrystalline soft magnetic materials are stress sensitive in the range of technical operation of inductive components based on such materials. [source] Aqueous exposure to 4-nonylphenol and 17,-estradiol increases stress sensitivity and disrupts ion regulatory ability of juvenile Atlantic salmonENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2007Darren T. Lerner Abstract Population declines of wild Atlantic salmon have been attributed to an array of anthropogenic disturbances, including dams, commercial and recreational fishing, habitat loss, and pollution. Environmental contaminants in particular, can act as environmental stressors on fish, typically causing disruption of ion homeostasis due to their close association with the aquatic environment. To examine the effects of the xenoestrogen 4-nonylphenol (NP) or 17,-estradiol (E2) on stress sensitivity and ion regulation, we exposed juvenile Atlantic salmon continuously for 21 d to either 10 or 100 ,g/L NP (NP-L or NP-H), 2 ,g/L E2 (positive control), or vehicle control during the parr-smolt transformation in April. After treatment, fish were sampled in freshwater (FW), transferred to 30, seawater (SW) for 24 h, or subjected to a handling stress. Estradiol and NP-H increased plasma vitellogenin in males and females, and E2 increased gonadosomatic index only in males. In FW, E2 reduced sodium potassium,activated adenosine triphosphatase activity as well as plasma levels of growth hormone, insulin-like growth factor I, and triiodothyronine. Both E2 and NP-H reduced plasma sodium in FW and increased plasma chloride in SW. Plasma Cortisol levels pre- and poststressor were significantly elevated by all treatments relative to controls, but only E2 increased plasma glucose before and after the stressor. These results indicate that exposure of anadromous salmonids to environmental estrogens heightens sensitivity to external stressors, impairs ion regulation in both FW and SW, and disrupts endocrine pathways critical for smolt development. [source] High-throughput behavioral phenotyping in the expanded panel of BXD recombinant inbred strainsGENES, BRAIN AND BEHAVIOR, Issue 2 2010V. M. Philip Genetic reference populations, particularly the BXD recombinant inbred (BXD RI) strains derived from C57BL/6J and DBA/2J mice, are a valuable resource for the discovery of the bio-molecular substrates and genetic drivers responsible for trait variation and covariation. This approach can be profitably applied in the analysis of susceptibility and mechanisms of drug and alcohol use disorders for which many predisposing behaviors may predict the occurrence and manifestation of increased preference for these substances. Many of these traits are modeled by common mouse behavioral assays, facilitating the detection of patterns and sources of genetic coregulation of predisposing phenotypes and substance consumption. Members of the Tennessee Mouse Genome Consortium (TMGC) have obtained phenotype data from over 250 measures related to multiple behavioral assays across several batteries: response to, and withdrawal from cocaine, 3,4-methylenedioxymethamphetamine; "ecstasy" (MDMA), morphine and alcohol; novelty seeking; behavioral despair and related neurological phenomena; pain sensitivity; stress sensitivity; anxiety; hyperactivity and sleep/wake cycles. All traits have been measured in both sexes in approximately 70 strains of the recently expanded panel of BXD RI strains. Sex differences and heritability estimates were obtained for each trait, and a comparison of early (N = 32) and recent (N = 37) BXD RI lines was performed. Primary data are publicly available for heritability, sex difference and genetic analyses using the MouseTrack database, and are also available in GeneNetwork.org for quantitative trait locus (QTL) detection and genetic analysis of gene expression. Together with the results of related studies, these data form a public resource for integrative systems genetic analysis of neurobehavioral traits. [source] The stress sensitivity of shaley sandstonesGEOPHYSICAL PROSPECTING, Issue 2 2007Colin MacBeth ABSTRACT The link between the stress sensitivity of shaley sandstones and their porosity and clay content is investigated. This is achieved by firstly fitting a compliance-based stress-sensitivity law to laboratory measurements of ultrasonic velocity taken from four sets of reservoir sandstones, extracted from a variety of depositional settings. Correlations are then sought between the independent parameters of this law and the porosity or clay fraction of the rocks, which are then subsequently interpreted in terms of framework or pore-space-related microstructural clay models. The general conclusion drawn from the results is that both of the parameters defining the stress-sensitivity law (the asymptotic modulus and the stress-dependent excess compliance) clearly vary with porosity. However, only the asymptotic modulus shows a convincing trend with clay and there is little observed variation of the stress-dependent compliance with clay. There is therefore a resultant variation of stress sensitivity with clay, but it is controlled only by the asymptotic modulus. The analysis also concludes that all four data sets fall into a framework-related category of clay model. [source] Design of the Magnetic Properties of Fe-Rich, Glass-Coated Microwires for Technical Applications,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2006A. Zhukov Abstract The magnetic anisotropy of Fe-rich, thin, amorphous wires is tailored by stress annealing (SA). In particular, the effect of conventional annealing (CA) and SA on the magnetic properties of Fe74B13Si11C2 glass-coated microwires is studied. CA treatment does not significantly change the character of the hysteresis loop. Under certain SA conditions (annealing temperature, Tann,>,300,°C; applied stress, ,,>,400,MPa), a transverse magnetic anisotropy is induced: a rectangular hysteresis loop transforms into an inclined one at magnetic-anisotropy fields above 1000,A,m,1. Under tensile stress, the rectangular hysteresis loop of microwires annealed using SA is recovered. Samples subjected to SA show noticeable magnetoimpedance and stress-impedance effects, despite their large magnetostriction. The samples obtained exhibit a high stress sensitivity of their giant magnetoimpedance (GMI) effect and hysteretic properties, allowing the use of the obtained samples in magnetoelastic sensors, and for designing stress-sensitive, tunable composite materials. By varying the time and temperature of such SA, we are able to tailor both the magnetic properties and the GMI of Fe-rich microwires. [source] Treatment with oxidizing agents damages the inner membrane of spores of Bacillus subtilis and sensitizes spores to subsequent stressJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2004D.E. Cortezzo Abstract Aims:, To determine if treatment of Bacillus subtilis spores with a variety of oxidizing agents causes damage to the spore's inner membrane. Methods and Results:, Spores of B. subtilis were killed 80,99% with wet heat or a variety of oxidizing agents, including betadine, chlorine dioxide, cumene hydroperoxide, hydrogen peroxide, OxoneTM, ozone, sodium hypochlorite and t-butylhydroperoxide, and the agents neutralized and/or removed. Survivors of spores pretreated with oxidizing agents exhibited increased sensitivity to killing by a normally minimal lethal heat treatment, while spores pretreated with wet heat did not. In addition, spores treated with wet heat or the oxidizing agents, except sodium hypochlorite, were more sensitive to high NaCl in plating media than were untreated spores. The core region of spores treated with at least two oxidizing agents was also penetrated much more readily by methylamine than was the core of untreated spores, and spores treated with oxidizing agents but not wet heat germinated faster with dodecylamine than did untreated spores. Spores of strains with very different levels of unsaturated fatty acids in their inner membrane exhibited essentially identical resistance to oxidizing agents. Conclusions:, Treatment of spores with oxidizing agents has been suggested to cause damage to the spore's inner membrane, a membrane whose integrity is essential for spore viability. The sensitization of spores to killing by heat and to high salt after pretreatment with oxidizing agents is consistent with and supports this suggestion. Presumably mild pretreatment with oxidizing agents causes some damage to the spore's inner membrane. While this damage may not be lethal under normal conditions, the damaged inner membrane may be less able to maintain its integrity, when dormant spores are exposed to high temperature or when germinated spores are faced with osmotic stress. Triggering of spore germination by dodecylamine likely involves action by this agent on the spore's inner membrane allowing release of the spore core's depot of dipicolinic acid. Presumably dodecylamine more readily alters the permeability of a damaged inner membrane and thus more readily triggers germination of spores pretreated with oxidizing agents. Damage to the inner spore membrane by oxidizing agents is also consistent with the more rapid penetration of methylamine into the core of treated spores, as the inner membrane is likely the crucial permeability barrier to methylamine entry into the spore core. As spores of strains with very different levels of unsaturated fatty acids in their inner membrane exhibited essentially identical resistance to oxidizing agents, it is not through oxidation of unsaturated fatty acids that oxidizing agents kill and/or damage spores. Perhaps these agents work by causing oxidative damage to key proteins in the spore's inner membrane. Significance and Impact of the Study:, The more rapid heat killing and germination with dodecylamine, the greater permeability of the spore core and the osmotic stress sensitivity in outgrowth of spores pretreated with oxidizing agents is consistent with such agents causing damage to the spore's inner membrane, even if this damage is not lethal under normal conditions. It may be possible to take advantage of this phenomenon to devise improved, less costly regimens for spore inactivation. [source] Chromate tolerance caused by reduced hydroxyl radical production and decreased glutathione reductase activity in Schizosaccharomyces pombeJOURNAL OF BASIC MICROBIOLOGY, Issue 2 2003Zoltán Gazdag The stable Cr(VI)-tolerant chr1-66T mutant of Schizosaccharomyces pombe, which carries one simple gene mutation responsible for Cr(VI) tolerance, accumulated and reduced the chromate anion (CrO42,) significantly more slowly than did its parental strain 6chr+. The mutant chr1-66T proved to be sensitive to oxidative stressors such as H2O2, menadione, tert -butyl hydroperoxide and Cd2+. Both the Cr(VI) tolerance and the oxidative stress sensitivity were attributed to a decreased specific glutathione reductase activity. These effects were also enhanced with a decrease in the specific mitochondrial Mn-SOD activity. [source] Congenital DNA repair deficiency results in protection against renal ischemia reperfusion injury in miceAGING CELL, Issue 2 2009Denis Susa Summary Cockayne syndrome and other segmental progerias with inborn defects in DNA repair mechanisms are thought to be due in part to hypersensitivity to endogenous oxidative DNA damage. The accelerated aging-like symptoms of this disorder include dysmyelination within the central nervous system, progressive sensineuronal hearing loss and retinal degeneration. We tested the effects of congenital nucleotide excision DNA repair deficiency on acute oxidative stress sensitivity in vivo. Surprisingly, we found mouse models of Cockayne syndrome less susceptible than wild type animals to surgically induced renal ischemia reperfusion injury, a multifactorial injury mediated in part by oxidative damage. Renal failure-related mortality was significantly reduced in Csb,/, mice, kidney function was improved and proliferation was significantly higher in the regenerative phase following ischemic injury. Protection from ischemic damage correlated with improved baseline glucose tolerance and insulin sensitivity and a reduced inflammatory response following injury. Protection was further associated with genetic ablation of a different Cockayne syndrome-associated gene, Csa. Our data provide the first functional in vivo evidence that congenital DNA repair deficiency can induce protection from acute stress in at least one organ. This suggests that while specific types of unrepaired endogenous DNA damage may lead to detrimental effects in certain tissues, they may at the same time elicit beneficial adaptive changes in others and thus contribute to the tissue specificity of disease symptoms. [source] Stress and GABAA receptorsJOURNAL OF NEUROCHEMISTRY, Issue 5 2010Kelly J. Skilbeck J. Neurochem. (2010) 112, 1115,1130. Abstract GABAA receptors are sensitive to subtle changes in the environment in both early-life and adulthood. These neurochemical responses to stress in adulthood are sex-dependent. Acute stress induces rapid changes in GABAA receptors in experimental animals, with the direction of the changes varying according to the sex of the animals and the stress-paradigm studied. These rapid alterations are of particular interest as they provide an example of fast neurotransmitter system plasticity that may be mediated by stress-induced increases in neurosteroids, perhaps via effects on phosphorylation and/or receptor trafficking. Interestingly, some studies have also provided evidence for long-lasting changes in GABAA receptors as a result of exposure to stressors in early-life. The short- and long-term stress sensitivity of the GABAergic system implicates GABAA receptors in the non-genetic etiology of psychiatric illnesses such as depression and schizophrenia in which stress may be an important factor. [source] Examining the Intersection of Sex and Stress in Modelling Neuropsychiatric DisordersJOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2009N. Goel Sex-biased neuropsychiatric disorders, including major depressive disorder and schizophrenia, are the major cause of disability in the developed world. Elevated stress sensitivity has been proposed as a key underlying factor in disease onset. Sex differences in stress sensitivity are associated with corticotrophin-releasing factor (CRF) and serotonin neurotransmission, which are important central regulators of mood and coping responses. To elucidate the underlying neurobiology of stress-related disease predisposition, it is critical to develop appropriate animal models of stress pathway dysregulation. Furthermore, the inclusion of sex difference comparisons in stress responsive behaviours, physiology and central stress pathway maturation in these models is essential. Recent studies by our laboratory and others have begun to investigate the intersection of stress and sex where the development of mouse models of stress pathway dysregulation via prenatal stress experience or early-life manipulations has provided insight into points of developmental vulnerability. In addition, examination of the maturation of these pathways, including the functional importance of the organisational and activational effects of gonadal hormones on stress responsivity, is essential for determination of when sex differences in stress sensitivity may begin. In such studies, we have detected distinct sex differences in stress coping strategies where activational effects of testosterone produced females that displayed male-like strategies in tests of passive coping, but were similar to females in tests of active coping. In a second model of elevated stress sensitivity, male mice experiencing prenatal stress early in gestation showed feminised physiological and behavioural stress responses, and were highly sensitive to a low dose of selective serotonin reuptake inhibitors. Analyses of expression and epigenetic patterns revealed changes in CRF and glucocorticoid receptor genes in these mice. Mechanistically, stress early in pregnancy produced a significant sex-dependent effect on placental gene expression that was supportive of altered foetal transport of key growth factors and nutrients. These mouse models examining alterations and hormonal effects on development of stress pathways provide necessary insight into how specific stress responses can be reprogrammed early in development resulting in sex differences in stress sensitivity and neuropsychiatric disease vulnerability. [source] Mood and anxiety psychopathology and temporomandibular disorder: a spectrum approachJOURNAL OF ORAL REHABILITATION, Issue 10 2004D. Manfredini summary, Psychological factors play an important role in the aetiopathogenesis of temporomandibular disorders (TMD), as demonstrated by an increase in stress, anxiety, depression and somatization in TMD patients. The aim of this work was to investigate the presence of mood and panic-agoraphobic symptoms in different groups of TMD patients by means of a spectrum approach to psychopathology. A total of 131 subjects were included in this study and TMD signs and symptoms were investigated by means of a standardized clinical examination. Two self-report questionnaires were used to evaluate mood (MOODS-SR) and panic-agoraphobic (PAS-SR) spectrum. anova and Bonferroni's post hoc test for multiple comparisons were used to compare mean scores of all TMD groups for MOODS-SR, PAS-SR and all their domains. Results revealed a significantly higher prevalence of both mood (P < 0·001) and panic-agoraphobic (P < 0·01) symptoms in myofascial pain patients than in all other diagnostic groups (TMD-free, disc displacement and joint disorders). With regard to mood spectrum, strong differences emerged for all domains evaluating depressive symptoms. As for the panic-agoraphobic spectrum, myofascial pain patients differed from the other groups for the presence of stress sensitivity, panic, separation anxiety, hypochondriac and agoraphobic symptoms. It was concluded that myofascial pain patients differed from those with disc displacement, joint disorders and no TMD in relation to some psychopathological symptoms, while the last three groups presented very similar profiles. [source] | |||||||||||||