High Negative Stress Research Articles

Association between Perceived Stress and Neutropenia in Patients with Leukemia under Chemotherapy.

Background: The most prominent part of the cellular response of the immune system is driven by neutrophils. These cells tend to decline following chemotherapy in patients with leukemia. Neutropenia is an influential factor in the prognosis of cancer patients. Stress reduces white blood cells (WBCs) and neutrophils are linked to an increased risk of infectious diseases after chemotherapy. We investigated the association between neutropenia and perceived stress following chemotherapy. Materials and Methods: We performed a cross-sectional study on 60 patients with leukemia in a university hospital. Participants completed self-report measures, including the demographic data and perceived stress scale (PSS) questionnaire. We compared rates of neutropenia, as a measure of chemotherapy prognosis, 10 days after chemotherapy in different stress levels. Moreover, the number of patients with polymorphonuclear (PMN) under 1000/microliter was compared at different stress levels. Results: We found that neutropenia is directly correlated with negative stress perception and inversely correlated with positive stress perception. These effects appear more prominent in patients with PMN under 1000/microliter as the number of these patients was significantly more in groups with higher negative stress and less in groups with higher positive stress scores. Conclusion: It can be concluded that stress is correlated with neutropenia, and stress management in patients with leukemia will be accompanied by better recovery outcomes and reduced risk of infectious disease.

Crack closure of Ni-based superalloy 718 at high negative stress ratios

Fatigue crack growth damage mechanisms for nickel-based superalloys at high, negative stress ratios challenge classical crack tip shielding and closure concepts. Fatigue crack growth rate and crack closure for single-edge notch Ni-based superalloy 718 specimens at 100°C were evaluated for several stress ratios (0.5, 0.1, −1, and −2). Multiple methods were used to calculate the effective driving force for crack growth rates in region II (i.e., Paris or power law regime). The relationships between the effective driving forces, the experimentally-measured crack closure levels, and the fractographic evidence of damage mechanisms are discussed.

The Effects of Stress Beliefs on Daily Affective Stress Responses.

Negative beliefs about the effects of stress have been associated with poorer health and increased mortality. However, evidence on the psychological mechanisms linking stress beliefs to health is scarce, especially regarding real-life stress. The aim of the current study was to investigate the effects of stress beliefs on affect in the daily stress process in a population prone to health-impairing effects of stress: university students. Using daily diaries, 98 university students reported on daily perceived social and work-related stressors as well as positive and negative affect for 10 consecutive days. Stress beliefs, depressive and anxiety symptoms, neuroticism, and demographic variables were assessed prior to the daily diary phase. Hierarchical linear models revealed a significant cross-level interaction between negative stress beliefs and the association of daily social stressors with negative affect (B = 0.24; 99% confidence interval [CI] = 0.08-0.41, p < .001). When experiencing social stress, participants who held high negative stress beliefs had higher daily negative affect (simple slope = 4.09; p < .001); however, for participants who held low negative stress beliefs the association between daily social stress and daily negative affect was considerably smaller (simple slope = 2.12; p < .001). Moreover, individuals believing stress to be controllable showed higher positive affect throughout the 10-day daily diary phase. Negative stress beliefs were found to moderate the affective response to daily real-life stressors. Given the established relationship between affect and health, this study provides initial evidence of psychological mechanisms linking stress beliefs to health.

Stress phase angle regulates differentiation of human adipose-derived stem cells toward endothelial phenotype

Endothelial cells are subjected to cyclic shear by pulsatile blood flow and pressures due to circumferential stresses. Although most of the researches on this topic have considered the effects of these two biomechanical forces separately or concurrently, few studies have noticed the interaction of these cyclic loadings on endothelial behavior. Negative temporal stress phase angle, defined by the phase lag between cyclic shear and tensile stresses, is an established parameter which is known to have substantial effects on blood vessel remodeling and progression of some serious cardiovascular diseases. In this research, intermittent shear and tensile stresses with different stress phase angle values were applied on human adipose stem cells (ASC). The expression level of three major endothelial-specific genes, elastic modulus of cells and cytoskeleton actin structure of cells were studied and compared among control and three test groups subjected to stress phase angle values at 0°, − 45°, and − 90°. Mechanical properties of ASCs were determined by atomic force microscopy and actin fiber structure was visualized by confocal imaging through Phalloidin staining. Results described a decrease in expression of FLK-1 and VE-cadherin and rise of vWF marker expression in case of higher negative stress phase angles. The Young’s moduli of cells were significantly higher and cytoskeletal actin structure was more organized with higher thickness for all test samples subjected to combined stresses; however, these features were less magnificent for applied stress phase angles with higher negative values. The results confirmed significant effects of SPA on endothelial differentiation of mesenchymal stem cells.

Role of Epicardial Fat to Buffer Deformation and Vibration in Coronary Arteries

Objectives: To examine the putative physiologic role of epicardial fat to buffer the coronary arteries and to review the data on deformation and vibration in coronary arteries. Methods: OvidSP Medline, Embase, and PubMed were systematically searched. Eligible articles on vibration in arteries and deformation of coronary arteries were assessed. Results: Coronary arteries are unique because they undergo substantial deformations with twisting, bending, and stretching that are due to cardiac contraction and the tethering of the large coronary arteries to the epicardial surface of the heart. In addition, phasic coronary artery pressure and blood flow are not synchronous producing a high negative stress phase angle between circumferential strain and wall shear. Fluid flow–induced vibrations, a universal finding in conduits transporting fluid with pulsatile flow, have been documented in arteries. Arterial vibration can damage the structure of arterial wall, especially elastin and endothelial cells, leading to alterations in the arterial function. Support for a beneficial mechanical role for epicardial fat is based on the data that wrapping material to the outside of conduits not only reduces the vibration but also decreases their movement. The overall impact of an external wrap is a reduction in the probability of conduit fatigue and failure. Characteristics of the artery, such as shear modulus, are a function of the properties of each layer of the artery. The application of epicardial fat to the adventitia of arteries alters the biophysical characteristics of the artery which is the sum of each layer including the epicardial fat. Vibration, resonance, and deformation energy are lost when they hit the surface of an absorbing material. Conclusions: The integration of the biophysics of coronary arteries with knowledge of material damping principles supports a physiologic role for epicardial fat to buffer deformation and vibration in coronary arteries.

Numerical study to indicate the vulnerability of plaques using an idealized 2D plaque model based on plaque classification in the human coronary artery.

Atherosclerosis is one of the leading causes of death in the world. In this study, an idealized 2D plaque model based on plaque classification in the coronary artery is developed. When creating the idealized 2D model for each plaque type (fibrocalcic, FC; fibrofatty, FT; calcified fibroatheroma, CaFA; fibroatheroma, FA; calcified thin-cap fibroatheroma, CaTCFA; thin-cap fibroatheroma, TCFA), the cap thickness and stenosis by diameter were set as variables. In order to establish the correlation between each plaque type and plaque rupture, a numerical simulation was performed and the stress and stress gradient were reviewed to analyze the mechanical behavior. Results show that both the TCFA and CaTCFA plaque types, which have the smallest cap thicknesses of the different types of plaque, showed relatively high stress values in the thin membrane when compared with the FT type. The FT type is considered to be relatively stable since it does not have necrotic core or a thin membrane. With a stenosis rate of 50% and a cap thickness of 60μm, the TCFA and CaTCFA types showed approximately 11 and 110% higher stress values, respectively, and 679 and 1568% higher negative stress gradient values, respectively. In other words, the plaque types with thin caps, which have weak load-bearing capacities, showed high stress values and high negative stress gradients in the radial direction. It is understood that this result could indicate the possibility of plaque rupture.

Understanding Stress in Multinational Companies in Thailand

Both quantitative and qualitative data were collected for this research. A total of 513 questionnaires were returned. Structural Equation Modeling techniques were used for statistical data analysis. The results of the analysis were used as a guideline to interview six managers. This research reveals: first, positive stress is the key factor for enhance job satisfaction based on the principle that stress should be moderately stimulated while excessive stimulation is likely to cause physical, and mental illnesses. Second, increasing negative stress also significantly leads to physical and psychological illness. Finally, the study shows that those who have high negative stress will have low job satisfaction. The study suggest that “Managing Pressure” training or Employee Assistance Program (EAP) should be organized to search for training programs suitable for the employees or organization should discover the cause of the problems.

The flow across a street canyon of variable width—Part 1: Kinematic description

Measurements have been made of the scalar dispersion of smoke released from a two-dimensional slot in the wall perpendicular to a boundary layer flow and located parallel to and midway between two square obstacles placed on the wall. The Reynolds number of the boundary layer at the slot location without the obstacles in place is R θ ≈ 980 . Two optical systems with CCD cameras facing each other have been used to measure simultaneously the velocity and scalar concentration fields, respectively, with PIV and Mie scattering diffusion. In Part B of this paper the data will ultimately provide detailed information about the scalar fluxes for this environmentally relevant geometry. Here in Part A the results of the velocity field measurements in the streamwise plane will be reported for spacings between the obstacles of 1–10 obstacle heights. The mean flow measurements reveal the increasing complexity of the canyon flow with increasing obstacle spacing. A primary vortex, with negative spanwise vorticity, occurs within the canyon for all spacings and is driven by the flow above. The circulation region of this vortex extends above the level of the tops of the obstacles. For spacings of 2 h and greater, a secondary vortex with positive vorticity appears in the upstream corner of the canyon, and a tertiary vortex with negative spanwise vorticity first appears in the downstream corner of the canyon for an opening of 6 h . The spatial distribution of the level of turbulence within and around the canyon is indicated by the contours of two-dimensional turbulent kinetic energy, 1 2 ( u 2 ¯ + v 2 ¯ ) . The region of elevated turbulence in the shear layer created by the upstream obstacle penetrates deeper into the canyon with increasing canyon opening. For all openings, the Reynolds shear stress is negative above the canyon. The vertical extent of the high negative stress region increases as the canyon opening increases, and it also penetrates well within the canyon. This region of negative stress is due to the transport, by the primary canyon vortex, of low momentum fluid from deep within the canyon upward and high momentum fluid from above the canyon downward.

Negative Stress and the Outcome of Treatment for Binge Eating

This study investigated the ability of negatively versus positively perceived stress to predict outcome of treatment for binge eating disorder (BED). Participants were 62 obese women satisfying the DSMIV research criteria for BED. Stress was measured using an instrument based on the Recent Life Change Questionnaire (RLCQ). Participants experiencing high negative stress during the study period reported a binge eating frequency three times greater than that reported by subjects experiencing low negative stress (2.14 vs. 0.65 binge-days/week). Negative stress predicted how fast an individual would reduce binge eating and demonstrated more predictive power than positive stress.