in this paper, we consider an  i.e., multiple step-stress accelerated life testing (alt) experiment with unequal duration of time . it is assumed that the time to failure of a product follows rayleigh distribution with a log-linear relationship between stress and lifetime and also we assume a generalized khamis-higgins model for the effect of changing stress levels. taking into account that the...

BACKGROUND/OBJECTIVES Stress-induced cognitive impairment is related to the suppression of hippocampal neurogenesis that results from an increase of oxidative stress. Therefore, the aim of this study was to investigate the effects of administration of a blueberry drink, having a high antioxidant power, on the cognitive performance of adult rats exposed to chronic mild stress. MATERIALS/METHOD...

Multiple sclerosis (MS) is the most common autoimmune disorder affecting the central nervous system. Most often diagnosed in young adults, MS runs a chronic, unpredictable course, often leading to severe disability: 50% of MS patients are unable to perform household and employment responsibilities 10 years after disease onset, and 50% are nonambulatory 25 years after disease onset. While it is ...

Stress influences synaptic plasticity, learning and memory in a steroid hormone receptor dependent manner. Based on these findings it has been proposed that stress could be a major risk factor for the development of cognitive decline and dementia. Interestingly, evidence has been provided that stress also affects muscarinic, i.e., acetylcholine (ACh)-mediated neurotransmission. To learn more ab...

Five experiments were conducted to test the hypothesis that psychosocial stress interferes with the estrous cycle of sheep. In experiment 1, ewes were repeatedly isolated during the follicular phase. Timing, amplitude, and duration of the preovulatory luteinizing hormone (LH) surge were not affected. In experiment 2, follicular-phase ewes were subjected twice to a "layered stress" paradigm cons...

In our daily life, individuals encounter with various types of stress. Accumulation of daily life stress (chronic stress) often causes gastrointestinal symptoms and functional gastrointestinal diseases. Although some can adapt toward chronic stress, the adaptation mechanism against chronic stress remains unknown. Although acute stress delays gastric emptying and alters upper gastrointestinal mo...

A procedure is presented for simulating the sequential impoundment process of concrete-faced rockfill dam using nonlinear finite element method. The parameters of constitutive relationship of stress and strain are determined by tri-dimensional compression test in laboratory. The model applied in this study adopts the technique of element birth and death to simulate the sequential impoundment pr...

the effects of dietary supplementation of grape seed extract (gse) and vitamin c on carcass characteristics, gut morphology and ileal microflora in broiler chickens exposed to chronic heat stress were examined. experimental diets included a control diet (without additive), 3 levels of gse (150, 300, 450 mg/kg of diet), and vitamin c (300 mg/kg of diet). each of the five diets was fed to 5 repli...

The rockfill is modeled as nonlinear elastic material, whose stress-dependent tangent modulus is related to the confining pressure. The parameters of constitutive relationship of stress and strain are determined by tri-dimensional compression test in laboratory. The model applied in this study adopts the technique of element birth and death to simulate the sequential impoundment process of conc...