Problems associated with direct displacement-based design of concrete bridges with single-column piers, and some suggested improvements

Currently available displacement-based design (DBD) procedures for bridges are critically evaluated with a view to identifying extensions and/or modifications of the procedure, for it to be applicable to final design of a fairly broad class of bridges. An improved direct DBD procedure is presented, including a suite of comprehensive design criteria and proper consideration of the degree of fixity of the pier top. The design of an overpass bridge (originally designed to a current European Code), applying the improved ‘direct’ displacement-based design (DDBD) procedure is presented and both ‘conventional’ and displacement-based designs are assessed using non-linear response-history analysis (NLRHA); comparisons are made in terms of both economy and seismic performance of the different designs. It is seen that DDBD provided a more rational base shear distribution among piers and abutments when compared to the force-based design procedure and adequately captured the displacement pattern, closely matching the results of the more rigorous NLRHA

Lung function variability in children and adolescents with and without asthma (LUV Study): Protocol for a prospective, nonrandomized, clinical trial

Background: Variability analysis of peak expiratory flow (PEF) and forced expiratory volume at 1 second (FEV1) has been used in research to predict exacerbations in adults with asthma. However, there is a paucity of data regarding PEF and FEV1 variability in healthy children and adolescents and those with asthma. Objective: The objective of this study is the assessment of PEF and FEV1 variability in (1) healthy children and adolescents, to define the normal daily fluctuation of PEF and FEV1 and the parameters that may influence it, and (2) children and adolescents with asthma, to explore the differences from healthy subjects and reveal any specific variability changes prior to exacerbation. Methods: The study will include 100 healthy children and adolescents aged 6-18 years (assessment of normal PEF and FEV1 variability) and 100 children and adolescents of the same age with diagnosed asthma (assessment of PEF and FEV1 variability in subjects with asthma). PEF and FEV1 measurements will be performed using an ultraportable spirometer (Spirobank Smart; MIR Medical International Research) capable of smartphone connection. Measurements will be performed twice a day between 7 AM and 9 AM and between 7 PM and 9 PM and will be dispatched via email to a central database for a period of 3 months. PEF and FEV1 variability will be assessed by detrended fluctuation and sample entropy analysis, aiming to define the normal pattern (healthy controls) and to detect and quantify any deviations among individuals with asthma. The anticipated duration of the study is 24 months. Results: The study is funded by the “C. Caratheodory” Programme of the University of Patras, Greece (PN 47014/24.9.2018). It was approved by the Ethics Committee (decision 218/19-03-2019) and the Scientific Board (decision 329/02-04-2019) of the University Hospital of Patras, Greece. Patient recruitment started in January 2020, and as of June 2020, 100 healthy children have been enrolled (74 of them have completed the measurements). The anticipated duration of the study is 24 months. The first part of the study (assessment of lung function variability in healthy children and adolescents) will be completed in August 2020, and the results will be available for publication by October 2020. ©Eirini-Sofia Frima, Ilias Theodorakopoulos, Dimos Gidaris, Nikolaos Karantaglis, Grigorios Chatziparasidis, Panagiotis Plotas, Michael Anthracopoulos, Sotirios Fouzas

Association of IL-10 gene promoter polymorphisms with food allergy susceptibility and serum IL-10 level in a pediatric Caucasian population

Background: Interleukin 10 has been shown to play a critical role in the regulation of the immune responses in allergic diseases. Aim: To investigate if genetic polymorphisms in the promoter region of the IL-10 gene are associated with food allergy (FA) susceptibility in Caucasian pediatric patients with concomitant allergic diseases and IL-10 levels. Methods: The single nucleotide polymorphisms (SNPs) at -1082A > G (rs1800896), -819 T > C (rs1800871), and -592A > C (rs1800872) of 62 pediatric patients with IgE-mediated FA were analyzed and correlated with clinical parameters, serum IgE and IL-10 levels. The results were compared with those of 92 healthy controls without FA, personal and/or family history of atopy. Results: Analysis and comparison of genotype distributions, allele frequencies, and haplotypes showed that none of the genotypes confers an increased risk of FA. The genotype -1082 AA in FA patients was associated with moderate to severe symptoms of FA, the development of atopic asthma, and higher levels of IL-10. In a linear regression study, we confirmed that the genotype -1082 AA acts as an independent factor for the higher levels of IL-10. A positive association was also observed between -819T/C and -592 A/C SNPs and later onset of FA. Conclusion: Polymorphisms in the promoter region of the IL-10 gene are not associated with FA susceptibility in our cohort. In FA patients, -1082 A/G SNPs seem to influence the production of IL-10, the severity of FA symptoms, and the development of atopic asthma in this population. © 2020 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd

Fragility Assessment of Transportation Infrastructure Systems Subjected to Earthquakes

This paper provides a review of the different methodologies for the fragility assessment of critical transportation infrastructure subjected to earthquake excitations with emphasis placed on geotechnical effects. Available approaches to fragility analysis are summarized, along with the main parameters and limitations. Additionally, definitions of damage are synthesized for the individual transportation assets and subsequently the definition of system of assets (SoA) is introduced. Numerical fragility curves are developed for a representative SoA subjected to seismic excitations. The paper concludes with the gaps in the area of fragility analysis and the needs for future development.acceptedVersion© 2018. This is the authors' accepted and refereed manuscript to the article. The final authenticated version is available online at: http://dx.doi.org/10.1061/9780784481479.01

Improving total-building seismic performance using linear fluid viscous dampers

Previous research has revealed that Eurocode-compliant structures can experience structural and nonstructural damage during earthquakes. Retrofitting buildings with fluid viscous dampers (FVDs) can improve interstorey drifts and floor accelerations, two structural parameters that characterize seismic demand. Previous research focusing on FVD applications for improving seismic performance has focused on structural performance. Structural parameters such as interstorey drifts and floor accelerations are often evaluated. Complexities arise as these parameters are often competing objectives. Other studies use damage indices that are influenced by several assumptions to represent performance. The use of repair costs is a more appropriate measure of total-building seismic performance, and avoids these limitations. This study investigates the application of linear FVDs to improve total-building seismic performance considering repair costs. The energy-based method commonly used to calculate damper coefficients is modified to improve its accuracy. The optimal amount of damping with respect to repair costs (estimated using the FEMA P-58 procedure) is identified as 25–45%. This contrasts with a previously suggested optimal damping of 20–25%, based on structural parameters, that is frequently targeted. This study on the damping-repair cost relationship provides insight when selecting levels of damping for structural designs and retrofits. It also highlights that retrofit methods may be enhanced by using repair costs, rather than structural parameters. The FVD buildings significantly reduce both drift-sensitive and acceleration-sensitive damage. Structural damage is also negligible in the FVD buildings: a major step towards achieving building serviceability following an ultimate limit state level earthquake