2,243 publications from this institution
Incremental dynamic analysis (IDA) is widespread to evaluate the seismic response of structures. It employs one records set scaled to multiple intensity levels (IMLs) to estimate the structural response distribution. However, the dominating earthquake scenarios differ with the intensity, and a single set introduces bias that increases with scaling. The response is, however, better estimated using multiple stripe analysis (MSA) by selecting multiple hazard consistent record sets at different IMLs via, for example, conditional spectrum (CS) method. Still, IDA remains a popular tool, and would benefit from a single “good” set that would be more amenable to scaling with minimal bias. We explore alternatives of a “multi-level” CS (CSML) scheme, whereby the seismic properties of multiple IMLs are combined to derive a single set. Combined with advanced IMs, CSML provides a viable trade-off between the more accurate and complex method of CS–MSA versus the conceptually and practically simpler IDA.
Abstract Background Only a few studies have been conducted with the objective of creating norms of the Alberta Infant Motor Scale (AIMS) for the assessment of gross motor development of preterm infants. The AIMS performance of preterm infants has been compared with that of the Canadian norms of full-term infants, but not with that of full-term infants of the same nationality. Moreover, the possible impact of prematurity-related morbidity factors on AIMS performance is unknown. Objectives The aims of this study were: (1) to evaluate AIMS trajectory in a large population of Greek preterm infants and create norms, (2) to compare it with the AIMS trajectory of Greek full-term infants, and (3) to examine the possible influence of neonatal morbidity on AIMS scores in the preterm sample. Design This was a cross-sectional study. Methods Mean AIMS scores were compared, per month (1–19), between 403 preterm infants (≤32 weeks of age, corrected for prematurity) and 1,038 full-term infants. In preterm infants, the association of AIMS scores with respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH) of grade ≤III, bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), and sepsis was assessed by hierarchical regression analysis. Results Alberta Infant Motor Scale scores were significantly lower in preterm infants than in full-term infants. Mean AIMS scores in preterm infants were significantly associated with RDS (b=−1.93; 95% CI=−2.70, −1.16), IVH (b=−0.97; 95% CI=−1.69, −0.25), and ROP (b=−1.12; 95% CI=−1.99, −0.24) but not with BPD or sepsis in hierarchical regression analysis. Conclusions Alberta Infant Motor Scale norms were created for Greek preterm infants. This study confirms that AIMS trajectories of preterm infants are below those of full-term infants of the same nationality. The influence of morbidity factors, including RDS, IVH, and ROP, should be taken into account when administering the AIMS in preterm infants.
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The molecular and biochemical bases for interactions between the immune and central nervous systems are described. Immune cytokines not only activate immune function but also recruit central stressresponsive neurotransmitter systems in the modulation of the immune response and in the activation of behaviors that may be adaptive during injury or inflammation. Peripherally generated cytokines, such as interleukin-1, signal hypothalamic corticotropin-releasing hormone (CRH) neurons to activate pituitary-adrenal counterregulation of inflammation through the potent anti-inflammatory effects of glucocorticoids. Corticotropin-releasing hormone not only activates the pituitary-adrenal axis but also sets in motion a coordinated series of behavioral and physiologic responses, suggesting that the central nervous system may coordinate both behavioral and immunologic adaptation during stressful situations. The pathophysiologic perturbation of this feedback loop, through various mechanisms, results in the development of inflammatory syndromes, such as rheumatoid arthritis, and behavioral syndromes, such as depression. Thus, diseases characterized by both inflammatory and emotional disturbances may derive from common alterations in specific central nervous system pathways (for example, the CRH system). In addition, disruptions of this communication by genetic, infectious, toxic, or pharmacologic means can influence the susceptibility to disorders associated with both behavioral and inflammatory components and potentially alter their natural history. These concepts suggest that neuropharmacology agents that stimulate hypothalamic CRH might potentially be adjunctive therapy for illnesses traditionally viewed as inflammatory or autoimmune.
This study aims to quantify the effect of the vertical component of ground motion on the seismic response of sliding rigid blocks, in terms of maximum and residual displacements. A multi-stripe analysis approach is employed to examine the response with and without the vertical component under various levels of ground motion intensity. First, a parametric study is conducted using a Coulomb friction model with a constant coefficient of friction that does not account for any dependence of the friction coefficient on velocity or pressure. It is shown that the effect of the vertical component on maximum and residual displacement is more pronounced for ground motions that can barely initiate sliding. Moreover, the influence of the vertical component on the residual sliding displacement is higher than that on the maximum displacement. Subsequently, to account for the friction coefficient dependence on pressure and sliding velocity, two interface cases (steel-steel, and concrete-concrete) are analyzed. It is found that even when a variable coefficient of friction is used, the overall trends observed for a constant coefficient of friction do not change.
Somatostatin (Sms) and its agonist analogues inhibit the secretory activities of endocrine and neural cells. Recent studies have suggested that Sms has significant immunomodulatory properties. In this study, we examine the effects of two Sms octapeptide analogues on the inflammatory reaction in vivo. BIM 23014 (Somatulin) and Sandostatin were administered to male Sprague-Dawley rats subject to carrageenin-induced aseptic inflammation, at doses of 2-10 micrograms/rat, given either systemically or locally. Animals were killed 7 h after the induction of the inflammation, and the inflammatory exudates were aspirated and quantitated in terms of volume and leukocyte concentration. Sms analogues, administered via either route, significantly reduced the volume and the leukocyte concentration of the exudate in a time- and dose-dependent fashion. In corroboration of these, immunohistochemical evaluation of the levels of local inflammatory mediators, such as immunoreactive (Ir) TNF-alpha, Irsubstance P, and Ircorticotropin-releasing hormone, was inhibited significantly by Sms analogue treatment. These findings suggest that Sms analogues have significant antiinflammatory effects in vivo, associated with suppression of proinflammatory cytokines and neuropeptides. Furthermore, these data suggest that Sms agonists may be useful in the control of inflammatory reaction.