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In September 2001 Aalborg university started the AAU-cubesat project that reached its climax when the student built satellite was launched into space on the 30th of June 2003 on top of a former Russian ICBM. AAU-cubesat was among the first five satellites to be launched that are built within the cubesat concept that prescribes a satellite with dimensions 10x10x10cm and mass one kilogram. This paper will describe the overall architecture of the AAU-cubesat in order to show what a pico-satellite can be and demonstrate all the fields of engineering which must come together to built a student satellite like the AAU-cubesat. Results from the operation phase will be stated, and recommendations on further work on pico-satellite designs will be given. In addition as the project has been carried through by students, the educational value of the project will be adressed as well.

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Background and purpose: There are concerns that bleeding following primary total hip arthroplasty (THA) contributes to prolonged wound drainage and prosthetic joint infection (PJI). We examined whether short (1–5 days), medium (6–14 days), and extended (≥ 15 days) duration of thromboprophylaxis is associated with the 5-year revision rate after THA due to osteoarthritis.Patients and methods: We performed a cohort study based on data from hip arthroplasty and administrative registries in Denmark and Norway (2008–2014). The outcome was revision surgery due to PJI, aseptic loosening or any cause, and patient mortality. Adjusted cause-specific hazard ratios (HRs) were analyzed with Cox regression analyses.Results: Among 50,482 THA patients, 8,333 received short, 17,009 received medium, and 25,140 received extended thromboprophylaxis. The HRs for revision due to PJI within 5 years were 1.0 (95%CI 0.7–1.3) and 1.1 (CI 0.9–1.3) for short and extended vs. medium treatment, whereas HR for extended vs. medium prophylaxis was 1.5 (CI 1.2–2.0) within 3 months. The HRs for revision due to aseptic loosening within 5 years were 1.0 (CI 0.7–1.4) and 1.1 (CI 0.9–1.4) for short and extended vs. medium treatment. The HRs for any revision within 5 years were 0.9 (CI 0.8–1.1) and 0.9 (CI 0.8–1.0) for short and extended vs. medium treatment. Extended vs. medium prophylaxis was associated with a decreased 0–3 month mortality. The absolute differences at 5 years were ≤ 1%.Conclusion: Our data suggests no association between duration of anticoagulant thromboprophylaxis and revision rate within 5 years of primary THA. The extended thromboprophylaxis might be associated with early increased revision rate due to PJI but also with lower mortality; however, the clinical relevance of this finding requires further research.