2,243 publications from this institution
The recent identification of ovine corticotropin releasing factor (CRF), a 41-amino acid peptide, provides a potential new approach to evaluate disorders of the hypothalamic-pituitary-vadrenal axis. We report here the effects of this new factor in the pituitary stalk-sectioned cynomolgus macaque. Given as an intravenous bolus, CRF stimulated cortisol secretion with an ED50 between 0 .1 and 1 μg⁄kg body weight. The peak cortisol response occurred after 15-30 min at low doses (0.5 - 1 μg⁄kg) and after 45-90 min at higher doses (2-40 μg⁄kg). This factor also stimulated the release of growth hormone and prolactin, but had no effect on TSH or LH secretion.
The bilinear approximation of force-deformation capacity curves is investigated for structural systems with non-negative-stiffness. This piecewise linear approximation process factually links capacity and demand; it lies at the core of the nonlinear static assessment pro- cedures, and it has become part of seismic guidelines and codes, such as ASCE-41 and Euro- code 8. Despite codification, the various fitting rules, used to derive the bilinear representation, can produce highly heterogeneous results for the same capacity curve. This is especially valid for highly-curved backbones resulting from structural models with accurate representation of the initial, uncracked, stiffness or buildings characterized by a global col- lapse mechanism that leads to a gradual plasticization of the elements. The error introduced by the bilinearization of the force-deformation relationship is quan- tified by studying it at the single-degree-of-freedom (SDOF) level, away from any interference from multi-degree-of-freedom (MDOF) effects, thus avoiding the issue related to MDOF - SDOF approximation. Incremental Dynamic Analysis (IDA) is employed to enable a direct comparison of the actual backbones versus their bilinear approximations in terms of the spec- tral acceleration capacity for a continuum of limit-states, allowing a direct comparison of the results in terms of seismic performance. Code-based procedures are found to be less than ideal wherever there are significant stiffness changes, while in general remaining relatively conservative. The practical fitting rules determined allow, instead, a near-optimal fit regardless of the details of the capacity curve shape.
To assess the seismic performance of a structural system within an analytical context, we need, among others, to specify a ground motion Intensity Measure (IM).The wary IM selection is undoubtedly an important step towards the successful implementation of a risk assessment, since insufficient and/or inefficient IMs can induce unwanted bias and variance in the vulnerability estimates.Supplementary issues related to practicality, necessitate the use of IMs for which ground motion prediction relationships exist, such as the elastic response spectral values (i.e.acceleration, velocity and displacement).Several past studies suggested as an improvement the use of IMs defined as the geometric mean of spectral acceleration values computed over a period range.The latter range may span between periods that are below, at or above the fundamental one.Some of these choices were proven to significantly improve both efficiency and sufficiency of the IM compared to more commonly used counterparts.
Early life stressors display a high universal prevalence and constitute a major public health problem. Prolonged psychoneurobiological alterations as sequelae of early life stress (ELS) could represent a developmental risk factor and mediate risk for disease, leading to higher physical and mental morbidity rates in later life. ELS could exert a programming effect on sensitive neuronal brain networks related to the stress response during critical periods of development and thus lead to enduring hyper- or hypo-activation of the stress system and altered glucocorticoid signaling. In addition, alterations in emotional and autonomic reactivity, circadian rhythm disruption, functional and structural changes in the brain, as well as immune and metabolic dysregulation have been lately identified as important risk factors for a chronically impaired homeostatic balance after ELS. Furthermore, human genetic background and epigenetic modifications through stress-related gene expression could interact with these alterations and explain inter-individual variation in vulnerability or resilience to stress. This narrative review presents relevant evidence from mainly human research on the ten most acknowledged neurobiological allostatic pathways exerting enduring adverse effects of ELS even decades later (hypothalamic-pituitary-adrenal axis, autonomic nervous system, immune system and inflammation, oxidative stress, cardiovascular system, gut microbiome, sleep and circadian system, genetics, epigenetics, structural, and functional brain correlates). Although most findings back a causal relation between ELS and psychobiological maladjustment in later life, the precise developmental trajectories and their temporal coincidence has not been elucidated as yet. Future studies should prospectively investigate putative mediators and their temporal sequence, while considering the potentially delayed time-frame for their phenotypical expression. Better screening strategies for ELS are needed for a better individual prevention and treatment.
In the last two decades, the biannual ECPPM (European Conference on Product and Process Modelling) conference series has provided a unique platform for the presentation and discussion of the most recent advances with regard to the ICT (Information and Communication Technology) applications in the AEC/FM (Architecture, Engineering, Construction and