We report on an online course in research writing offered in a massive open online course (MOOC) format for developing country researchers. The concepts of cognitive presence, teacher presence, and social presence informed the design of the course, with a philosophy of strong social interaction supported by guest facilitators. The course was developed with low-bandwidth elements and hosted on a Moodle site. It was offered twice as a MOOC and 2830 learners from more than 90 countries, mainly in the developing world, took part. The average completion rate was 53%. Female learners and learners who were active in the forums were more likely to complete the course. Our MOOC approach may be a useful model for continuing professional development training in the developing world.
A hollow-cathode microplasma modified the lumenal surface of small-diameter polyethylene (PE) tubing. A microwave cavity diagnostic was used to measure the density of the microplasma. Plasma light output was observed with a monochromator at various positions along the PE tube to assess uniformity. Treatment effectiveness was evaluated by measuring the variation in capillary rise at various positions along the tubing. A correlation between the properties of the inner surface of the PE tubing and the emitted light intensity was found. A poly(ethylene oxide) surfactant was immobilized to the lumenal surface of the PE tubing with an argon microplasma discharge. To test hematocompatibility, an in vitro blood-flow loop circulated heparinized human blood through both a plasma-treated and -untreated PE tubes, simultaneously. After blood exposure, the tubes were examined with a scanning electron microscope to assess the density of adhering platelets along the length of the tubes. By modifying the plasma parameters, the uniformity of the microplasma treatment along the tubing can be optimized.
Abstract-A hollow-cathode microplasma was used to modify the lumenal surface of small-diameter polyethylene (PE). We make use of two microplasma diagnostics to monitor the plasma properties during the treatment process. A microwave cavity was used to measure the density of the microplasma. Emitted light from the microplasma was fed into a monochromator at various positions along the PE tube to assess uniformity of the microplasma. Effectiveness of plasma treatments were evaluated using the capillary-rise method at various positions along the tubing. We show a correlation between the properties of the inner surface of the PE tubing and the light emitted from the plasma. A Poly(ethylene oxide) (PEO) surfactant was immobilized to the lumenal surface of the PE tubing using the microplasma discharge. An in vitro blood-circulation loop was constructed to test the hematocompatibility of the PE tubes. After blood exposure, scanning electron microscope images were taken to assess the density of adhering platelets along the length of the tubes. The plasma-treated tubing showed fewer blood adherents than the untreated tubing. By suitably controlling the pressure drop along the tube, the uniformity of the microplasma treatment along the tubing can be optimized.
Hematocompatibility and nonfouling properties of materials are crucial for the development of small-scale biomedical devices. This study examines the adhesion and morphology of purified human platelets on plasma-polymerized tetraglyme-coated glass substrates. The effect of varying the plasma-processing parameters on platelet responses was determined using scanning electron microscopy. Images of platelets on the coated surfaces show that a significant reduction in platelet adhesion and spreading can be achieved as the processing parameters are varied.
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