-Arterial oxygen saturation (SpO 2 ) monitoring for newborns requires special attention in neonatal intensive care units (NICUs). Newborns have very low photo-plethysmogram (PPG) amplitudes and their body movements are difficult to contain. Hardware design and its associated signal processing algorithms should be robust enough so that faulty measurements can be avoided. In this study, improved designs were implemented to deal with low perfusion, motion artifact, and the influence of ambient light. Dynamic range was increased by using different LED intensities and a feedback system. To minimize the effects of motion artifact and to discard other unqualified data, four additional algorithms were used, which were based on dual-trace detection, continuity of DC level, morphology of PPG, and simultaneity check of SpO 2 . Our SpO 2 system was tested with newborns with normal respiration in the NICU. Our system provided fast, real-time responses and 100% artifact detection was accomplished under 84% of SpO 2 .
Characterization of an hyaluronic acid (HA)-poly(ethylene oxide) (PEO) hydrogel was
performed by changing the number of side arms in a PEO molecule. Verification of grafting
chemistry and mechanical strength, as well as swelling behaviors and surface morphologies of the
HA-PEO hydrogels were analyzed by employing different x-linking molecular weights (MW) of
PEO ranging from 1.7 to 5.0 kDa at a fixed low MW HA in the hydrogel network. Methacrylation
to the HA successfully obtained via Michael type reaction between the methacrylate arm groups in
HA and the thiol end groups in PEO was observed by XPS. Hydrogel formation was markedly
dependent upon the numbers of thiol groups in the PEO molecule. Furthermore the lower MW
PEO-based HA hydrogel demonstrated stronger mechanical properties but lower water absorption
and the smaller pore sizes on its surface and cross section.
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