237 research outputs found

    Role of charge patches in ion guiding through nanocapillaries in a PET polymer

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    We studied the dynamic properties of ion guiding through nanocapillaries in insulating polyethylene terephthalate (PET). The angular distribution of the transmitted ions was measured as a function of time. The temporal evolution of the angular transmission profiles was acquired for the capillary diameters of 200 and 400 nm. The tilt angle was varied from 0° to 6.5°. The transmission profiles exhibit significant changes in position as time varies. This observation is explained by the formation of temporary charge patches produced in the interior of the capillary besides the primary charge patch created in the entrance region.</p

    Stress-Induced Allodynia – Evidence of Increased Pain Sensitivity in Healthy Humans and Patients with Chronic Pain after Experimentally Induced Psychosocial Stress

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    Background: Experimental stress has been shown to have analgesic as well as allodynic effect in animals. Despite the obvious negative influence of stress in clinical pain conditions, stress-induced alteration of pain sensitivity has not been tested in humans so far. Therefore, we tested changes of pain sensitivity using an experimental stressor in ten female healthy subjects and 13 female patients with fibromyalgia. Methods: Multiple sensory aspects of pain were evaluated in all participants with the help of the quantitative sensory testing protocol before (60 min) and after (10 and 90 min) inducing psychological stress with a standardized psychosocial stress test (“Trier Social Stress Test”). Results: Both healthy subjects and patients with fibromyalgia showed stress-induced enhancement of pain sensitivity in response to thermal stimuli. However, only patients showed increased sensitivity in response to pressure pain. Conclusions: Our results provide evidence for stress-induced allodynia/hyperalgesia in humans for the first time and suggest differential underlying mechanisms determining response to stressors in healthy subjects and patients suffering from chronic pain. Possible mechanisms of the interplay of stress and mediating factors (e.g. cytokines, cortisol) on pain sensitivity are mentioned. Future studies should help understand better how stress impacts on chronic pain conditions

    Safer Sex as the Bolder Choice: Testosterone Is Positively Correlated with Safer Sex Behaviorally Relevant Attitudes in Young Men

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    Introduction.  Higher testosterone (T) is tied to risk‐taking, especially in financial domains but also in health domains relevant to acquiring sexually transmitted infections (STIs). However, safer sex constructs could themselves carry the possibility of “social risk” due to sexual stigma or embarrassment, or could involve boldness or confidence because they could represent status displays of frequent sexual activity. Aim.  To determine how T and behaviorally relevant attitudes about sexual risk‐taking are linked, to better understand biopsychosocial aspects of sexual health related to STIs. Methods.  In 78 first‐year male college students, we examined correlations between salivary T and behaviorally relevant safer sex attitudes assessed via questionnaires. Main Outcome Measures.  T, via saliva; safer sex attitudes, via a composite and the University of California, Los Angeles Multidimensional Condom Attitudes Scale (MCAS). Results.  Higher T was significantly correlated with higher scores on the following: safer sex likelihood composite, r (73) = 0.33, P  = 0.003; the MCAS safer sex resilience, r (32) = 0.36, P  = 0.037; and the MCAS condom purchase comfort, r (32) = 0.37, P  = 0.031. Associations between T and safer sex likelihood and resilience were still robust after controlling for potential confounds, though the association between T and purchase comfort diminished to a trend. Conclusions.  Higher T was positively linked with safer sex attitudes, especially those most closely tied to STI risk avoidance. Thus, future research and interventions for STI prevention should address the possibility that safer sex may be paradoxically perceived as a “bold” or “risky” choice even as it decreases STI risk. van Anders SM, Goldey KL, Conley TD, Snipes DJ, and Patel DA. Safer sex as the bolder choice: Testosterone is positively correlated with safer sex behaviorally relevant attitudes in young men. J Sex Med 2012;9:727–734.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90413/1/j.1743-6109.2011.02544.x.pd

    Associations between DSM-IV diagnosis, psychiatric symptoms and morning cortisol levels in a community sample of adolescents

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    Purpose. Dysfunction of the hypothalamic-pituitary-adrenocortical axis (HPA-axis) is implicated in a variety of psychiatric and emotional disorders. In this study, we explore the association between HPA-axis functioning, as measured by morning cortisol, and common psychiatric disorders and symptoms among a community sample of adolescents. Method. Data from a cross-sectional school-based survey of 501 school pupils, aged 15, were used to establish the strength of association between salivary morning cortisol and both diagnosis of psychiatric disorders and a number of psychiatric symptoms, as measured via a computerised psychiatric interview. Analysis, conducted separately by gender, used multiple regressions, adjusting for relevant confounders. Results-á-áWith one exception (a positive association between conduct disorder symptoms and cortisol among females) there was no association between morning cortisol and psychiatric diagnosis or symptoms. However, there was a significant two-way interaction between gender and conduct symptoms, with females showing a positive and males a negative association between cortisol and conduct symptoms. A further three-way interaction showed that while the association between cortisol and conduct symptoms was negative among males with a few mood disorder symptoms, among females with many mood symptoms it was positive. Conclusions. Except in relation to conduct symptoms, dysregulation of morning cortisol levels seems unrelated to any psychiatric disorder or symptoms. However, the relationship between cortisol and conduct symptoms is moderated by both gender and mood symptoms. Findings are compatible with the recent work suggesting research should concentrate on the moderated associations between gender, internalising and externalising symptoms and cortisol, rather than any simple relationship

    Active behaviour during early development shapes glucocorticoid reactivity

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    TGlucocorticoids are the final effectors of the stress axis, with numerous targets in the central nervous system and the periphery. They are essential for adaptation, yet currently it is unclear how early life events program the glucocorticoid response to stress. Here we provide evidence that involuntary swimming at early developmental stages can reconfigure the cortisol response to homotypic and heterotypic stress in larval zebrafish (Danio rerio), also reducing startle reactivity and increasing spontaneous activity as well as energy efficiency during active behaviour. Collectively, these data identify a role of the genetically malleable zebrafish for linking early life stress with glucocorticoid function in later life

    Pre-Operative Cognitive Functioning and Inflammatory and Neuroendocrine Responses to Cardiac Surgery.

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    BACKGROUND: Cognitive functioning is linked to cardiac mortality and morbidity, but the mechanisms underlying this relationship are unclear. PURPOSE: To examine the relationship between pre-operative cognitive functioning and post-operative inflammatory and neuroendocrine responses in patients undergoing coronary artery bypass graft (CABG) surgery. METHODS: One-hundred ninety-three outpatients were screened to assess their cognitive function using the Montreal Cognitive Assessment (MoCA) on average 30 days prior to CABG surgery and provided blood samples for the measurement of interleukin (IL)-6 and C-reactive protein (CRP) and saliva samples for the measurement of diurnal cortisol. Participants were followed-up 4-8 days following surgery for the repeat measurement of IL-6 and CRP and 60 days after surgery for the measurement of diurnal salivary cortisol. RESULTS: Patients with low cognitive function (MoCA < 26) prior to surgery reached higher IL-6 concentrations in the days after surgery (β = -0.212, p = 0.021) and had greater cortisol output across the day 2 months after surgery (β = -0.179, p = 0.044). CONCLUSIONS: Low cognitive functioning is associated with a more negative pattern of biological response to surgery, indicative of poorer physical recovery. These pathways may contribute to the links between cognitive function and cardiovascular pathology

    Salivary biomarkers of HPA axis and autonomic activity in adults with intellectual disability with and without stereotyped and self-injurious behavior disorders

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    Salivary levels of biomarkers for the hypothalamic–pituitary–adrenal axis (HPA; cortisol) and sympatho-adreno-medullary system (SAM; α-amylase) were measured in 51 adults (57% male) with neurodevelopmental disorders associated with intellectual disability (i.e., mental retardation) and chronic self-injurious behavior (SIB) and compared with matched controls without SIB. Cortisol levels differed significantly (p < 0.01) between the SIB and control group (SIB > control). Within-group analyses showed significant differences (p < 0.05) in levels of salivary α-amylase between individuals with SIB and those with SIB meeting criteria for stereotyped movement disorder (SMD; SIB + SMD > SIB). Salivary α-amylase was significantly correlated with frequency of stereotypy among the SIB group (r = 0.36, p < 0.05). These preliminary findings warrant further exploration into the role of the SAM system in the pathophysiology of SIB and related repetitive behaviors among individuals with neurodevelopmental disorders associated with intellectual disability

    Phospholipids and sports performance

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    Phospholipids are essential components of all biological membranes. Phosphatidylcholine (PC) and Phosphatidylserine (PS) are Phosphatidyl-phospholipids that are required for normal cellular structure and function. The participation in physical activity often challenges a variety of physiological systems; consequently, the ability to maintain normal cellular function during activity can determine sporting performance. The participation in prolonged intense exercise has been shown to reduce circulatory choline concentrations in some individuals. As choline is a pre-cursor to the neurotransmitter Acetylcholine, this finding has encouraged researchers to investigate the hypothesis that supplementation with PC (or choline salts) could enhance sporting performance. Although the available data that evaluates the effects of PC supplementation on performance are equivocal, acute oral supplementation with PC (~0.2 g PC per kg body mass) has been demonstrated to improve performance in a variety of sporting activities where exercise has depleted circulatory choline concentrations. Short term oral supplementation with soy-derived PS (S-PS) has been reported to attenuate circulating cortisol concentrations, improve perceived well-being, and reduce perceived muscle soreness after exercise. More recently, short term oral supplementation (750 mg per day of S-PS for 10 days) has been demonstrated to improve exercise capacity during high intensity cycling and tended to increase performance during intermittent running. Although more research is warranted to determine minimum dietary Phospholipid requirements for optimal sporting performance, these findings suggest that some participants might benefit from dietary interventions that increase the intakes of PC and PS
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