Adaptive structures in civil engineering are mechanical structures with the ability to modify their response to external loads. Actuators strongly affect a structure’s adaptivity and have to be placed thoughtfully in the design process to effectively compensate external loads. For constant loads, this property is introduced as steady-state disturbance compensability. This property can be linked to concepts from structural engineering such as redundancy or statical indeterminacy, thus representing an interdisciplinary approach. Based on the disturbance compensability matrix, a scalar performance metric is derived as quantitative measure of a structure’s ability to compensate the output error for arbitrary constant disturbances with a given set of actuators. By minimizing this metric, an actuator configuration is determined. The concept is applied to an example of a truss structure.
The goal of this research project is to find an answer to today's most urgent social and ecological questions as the global population continuously increases and the available resources remain limited. As the central approach to the solution of this problem, adaptive elements will be included in the structure, the interior and the façade of an experimental 37 m tall building. This paper introduces the topic of adaptivity in building structures and provides an overview of the research topics applied in this globally unique adaptive high-rise building. Due to the complexity of research topics of this Collaborative Research Centre, this paper only covers the research concerning the experimental high-rise building.
OBJECTIVES
Optimal vitamin D status is known to have beneficial health effects and vitamin D supplements are commonly used. It has been suggested that vitamin D supplementation may increase blood lead in children and adults with previous lead exposure. The objective was to determine the safety regarding lead toxicity during 12 weeks of high dose vitamin D3 supplementation in children and young adults with HIV.
METHODS
Subjects with HIV (age 8 to 24 yrs) were randomized to vitamin D3 supplementation of 4000 IU/day or 7000 IU/day and followed at 6 and 12 weeks for changes in 25D and whole blood lead concentration. This was a secondary analysis of a larger study of vitamin D3 supplementation in children and adolescents with HIV.
RESULTS
In 44 subjects (75% African American), the baseline mean ± SD serum 25D was 48.3 ± 18.6 nmol/L. 50% of subjects had baseline serum 25D < 50.0 nmol/L. Serum 25D increased significantly with D3 supplementation over the 12 weeks. No subject had a whole blood lead >5.0 μg/dL at baseline or during subsequent visits. Whole blood lead and 25D were not correlated at baseline, and were negatively correlated after 12 weeks of supplementation (p= 0.014). Whole blood lead did not differ between those receiving 4000 IU versus 7000 IU of vitamin D3.
CONCLUSION
High dose vitamin D3 supplementation and the concomitant increased serum 25D did not result in increased whole blood lead concentration in this sample of children and young adults living in a northeastern urban city.
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