Algorithm Engineering in Robust Optimization

Robust optimization is a young and emerging field of research having received a considerable increase of interest over the last decade. In this paper, we argue that the the algorithm engineering methodology fits very well to the field of robust optimization and yields a rewarding new perspective on both the current state of research and open research directions. To this end we go through the algorithm engineering cycle of design and analysis of concepts, development and implementation of algorithms, and theoretical and experimental evaluation. We show that many ideas of algorithm engineering have already been applied in publications on robust optimization. Most work on robust optimization is devoted to analysis of the concepts and the development of algorithms, some papers deal with the evaluation of a particular concept in case studies, and work on comparison of concepts just starts. What is still a drawback in many papers on robustness is the missing link to include the results of the experiments again in the design

Increased platelet content of SDF-1alpha is associated with worse prognosis in patients with pulmonary prterial hypertension

Inflammatory processes and platelet activity play an important role in the pathophysiology of pulmonary arterial hypertension (PAH). Enhanced IL-6 signaling and higher concentration of stromal-derived factor alpha (SDF-1) have been previously shown to be linked with prognosis in PAH. We hypothesized that platelets of PAH patients have higher content of IL-6 and SDF-1 and thus are involved in disease progression. We enrolled into study 22 PAH patients and 18 healthy controls. Patients with PAH presented significantly higher plasma concentrations and platelet contents of IL-6, sIL-6R, and SDF-1 than healthy subjects (platelet content normalized to protein concentration: IL-6 (0.85*10–10 [0.29 – 1.37] vs. 0.45*10–10 [0.19–0.65], sIL-6R 1.54*10–7 [1.32–2.21] vs. 1.14*10–7 [1.01–1.28] and SDF-1 (2.72*10–7 [1.85–3.23] vs. 1.70*10–7 [1.43–2.60], all p < 0.05). Patients with disease progression (death, WHO class worsening, or therapy escalation, n = 10) had a significantly higher platelet SDF-1/total platelet protein ratio (3.68*10–7 [2.45–4.62] vs. 1.69*10–7 [1.04–2.28], p = 0.001), with no significant differences between plasma levels. Kaplan–Meier analysis revealed that patients with higher platelet SDF-1/total platelet protein ratio had more frequently deterioration of PAH in the follow-up (15.24 ± 4.26 months, log-rank test, p = 0.01). Concentrations of IL-6, sIL-6 receptor and SDF-1 in plasma and platelets are elevated in PAH patients. Higher content of SDF-1 in platelets is associated with poorer prognosis. Our study, despite of limitation due to small number of enrolled patients, suggests that activated platelets may be an important source of cytokines at the site of endothelial injury, but their exact role in the pathogenesis of PAH requires further investigation