Design, Modeling and Evaluation of a 2.4GHz FHSS Communications System for NarcisSat

Communication subsystems generally consume the majority of power and a significant fraction of mass and volume for picosatellites, and thus their design is critical to the overall satellite and mission plans. The available data bandwidth defines the types of payloads that can be accommodated. Until now, most CubeSat designs have used the 2m (145MHz) and 70cm (437MHz) bands. We present simulation and experimental measurements of a commercial, off-theshelf (COTS) spread spectrum 2.4GHz system that is incorporated on NarcisSat, a CubeSat scheduled for launch in late 2003. In the 2.4GHz band, patch antennas instead of monopoles are suitable, eliminating the need to deploy antennas on orbit. With the system presented here, data rates of up to 115kbps are possible, facilitating new kinds of more data intensive payloads than previously possible in CubeSats. Spread spectrum is well suited for multiple CubeSat deployment and handles ground-based noise better than narrowband communications. We also address the attitude control subsystem and ground station requirements of this system

N-terminal PDZ-binding domain in Kv1 potassium channels

AbstractWe have investigated the interactions of prototypical PDZ domains with both the C- and N-termini of Kv1.5 and other Kv channels. A combination of in vitro binding and yeast two-hybrid assays unexpectedly showed that PDZ domains derived from PSD95 bind both the C- and N-termini of the channels with comparable avidity. From doubly transfected HEK293 cells, Kv1.5 was found to co-immunoprecipitate with the PDZ protein, irrespective of the presence of the canonical C-terminal PDZ-binding motif in Kv1.5. Imaging analysis of the same HEK cell lines demonstrated that co-localization of Kv1.5 with PSD95 at the cell surface is similarly independent of the canonical PDZ-binding motif. Deletion analysis localized the N-terminal PDZ-binding site in Kv1.5 to the T1 region of the channel. Co-expression of PSD95 with Kv1.5 N- and C-terminal deletions in HEK cells had contrasting effects on the magnitudes of the potassium currents across the membranes of these cells. These findings may have important implications for the regulation of channel expression and function by PDZ proteins like PSD95

Thanks for Making It | S1E5: Designing for a Feeling & Turning a Passion Into a Successful Business - Kyle Doerksen of Onewheel

You have probably ridden an electric car or scooter, but have you ever ridden a Onewheel? This lightweight mobility vehicle has one giant wheel and a motor, and sensors that control the motion of the motor to balance you. So it balances for you, and you lean forward to go, back to slow down, and lean on the side to make a turn. But perhaps most importantly, it is designed to create a joyful feeling while riding it. What does it mean to design and engineer a product for a feeling? In this episode of Thanks for Making It, our host Beth Altringer Eagle interviews Kyle Doerksen, the creator of Onewheel. They discuss his background in design and engineering, how he turned a Design Engineering passion into a successful business while still working at IDEO, Onewheel\u27s creative process, and the many benefits of mixing design and engineering.https://digitalcommons.risd.edu/industrialdesign_thanksformakingitpodcast/1004/thumbnail.jp

Separation of P/C- and U-type inactivation pathways in Kv1.5 potassium channels

P/C-type inactivation of Kv channels is thought to involve conformational changes in the outer pore of the channel, culminating in a partial constriction of the selectivity filter. Recent studies have identified a number of phenotypic differences in the inactivation properties of different Kv channels, including different sensitivities to elevation of extracellular K(+) concentration, and different state dependencies of inactivation. We have demonstrated that an alternatively spliced short form of Kv1.5, resulting in disruption of the T1 domain, exhibits a shift in the state dependence of inactivation in this channel, and in the current study we have examined this further to contrast the properties of inactivation from open versus closed states. In a TEA(+)-sensitive mutant of Kv1.5 (Kv1.5 R487T), 10 mm extracellular TEA(+) inhibits inactivation in both full-length and T1-deleted channels, but does not inhibit closed-state inactivation in T1-deleted channel forms. Similarly, substitution of K(+) and Na(+) with Cs(+) ions in the recording medium inhibits inactivation of both full-length and T1-deleted channel forms, but fails to inhibit closed-state inactivation of T1-deleted channels. Collectively, these data distinguish between open-state and closed-state inactivation, and suggest the presence of multiple possible mechanisms of inactivation coexisting in Kv1 channels