Abstract: Various embodiments of devices and systems comprising a polymer driveshaft for use in high-speed rotational medical procedures, e.g., atherectomy, are disclosed. Generally, the primary driveshaft for transferring torque and activating rotation of a tool attached thereto, e.g., an abrasive element, is constructed with at least a polymer outer and inner surface. In certain embodiments, the polymer driveshaft may comprise a metallic band for fixed attachment of a structure, e.g., an abrasive element, thereto. Various embodiments may comprise a coupler that connects a drive shaft connected with a prime mover, e.g., a turbine or electric motor, with the polymer drive shaft, the coupler comprising openings through the coupler wall to the inner diameter of the coupler to allow fluid flow to the inner diameter of the coupled polymer drive shaft.

Abstract: A fuel cell membrane electrode assembly having: a proton exchange membrane, an anode catalyst coating on one side of the membrane, and a cathode catalyst coating on the other side of the membrane. The cathode catalyst coating has at least two carbon catalyst layers, with a low porosity layer adjacent to a high porosity layer. The high porosity layers have a volume fraction that is higher than the volume fraction of the low porosity layers.

Abstract: A fuel cell membrane electrode assembly having: a proton exchange membrane, an anode catalyst coating on one side of the membrane, and a cathode catalyst coating on the other side of the membrane. The cathode catalyst coating has at least two carbon catalyst layers, with a low porosity layer adjacent to a high porosity layer. The high porosity layers have a volume fraction that is higher than the volume fraction of the low porosity layers.

Abstract: The invention is a cost effective, structural building set, suitable as a toy, using post connectors (10) comprised of a post (12) with attached disks (14), or similar devices that insert into cutouts (31) in geometric shaped component parts (30, 80). More than one component part can be connected to the same post connector, and such component parts can rotate relative to the post axis. The connector design allows construction of stable structures of many sizes, shapes, and types, and readily facilitates hinging between different sections of such assembled structures.

Abstract: According to one aspect, embodiments of the invention provide a recreational floatation device comprising a body portion comprising an inflatable member having a first inner perimeter surrounding a first inner area, a first support portion comprising a layer of material extending through the first inner area and attached to the inflatable member at its first inner perimeter to support a user of the device, a back support member located within said first inner area, a hinge mechanism coupled to the back support member and the first inner perimeter and configured to allow the back support member to rotate between a first position, wherein a substantial portion of the back support member extends generally away from the first inner area, and a second position, in which the back support member lies substantially within the first inner area.

Abstract: According to one aspect, embodiments of the invention provide a recreational floatation device comprising a body portion comprising an inflatable member having a first inner perimeter surrounding a first inner area, a first support portion comprising a layer of material extending through the first inner area and attached to the inflatable member at its first inner perimeter to support a user of the device, a back support member located within said first inner area, a hinge mechanism coupled to the back support member and the first inner perimeter and configured to allow the back support member to rotate between a first position, wherein a substantial portion of the back support member extends generally away from the first inner area, and a second position, in which the back support member lies substantially within the first inner area.

Abstract: According to one aspect, embodiments of the invention provide a recreational floatation device comprising a body portion comprising an inflatable member having a first inner perimeter surrounding a first inner area, a first support portion comprising a layer of material extending through the first inner area and attached to the inflatable member at its first inner perimeter to support a user of the device, a back support member located within said first inner area, a hinge mechanism coupled to the back support member and the first inner perimeter and configured to allow the back support member to rotate between a first position, wherein a substantial portion of the back support member extends generally away from the first inner area, and a second position, in which the back support member lies substantially within the first inner area.

Abstract: According to one aspect, embodiments of the invention provide a recreational floatation device comprising a body portion comprising an inflatable member having a first inner perimeter surrounding a first inner area, a first support portion comprising a layer of material extending through the first inner area and attached to the inflatable member at its first inner perimeter to support a user of the device, a back support member located within said first inner area, a hinge mechanism coupled to the back support member and the first inner perimeter and configured to allow the back support member to rotate between a first position, wherein a substantial portion of the back support member extends generally away from the first inner area, and a second position, in which the back support member lies substantially within the first inner area.

Abstract: A floating mattress includes a first section coupled to a second section by a joint which provides for the first section to rotate relative to the second section. At least one the first section and the second section is filled with a buoyant material. A sidewall of at least one the first section and the second section is permeable to water.

Abstract: According to one aspect, embodiments of the invention provide a recreational floatation device comprising a body portion comprising an inflatable member having a first inner perimeter surrounding a first inner area, a first support portion comprising a layer of material extending through the first inner area and attached to the inflatable member at its first inner perimeter to support a user of the device, a back support member located within said first inner area, a hinge mechanism coupled to the back support member and the first inner perimeter and configured to allow the back support member to rotate between a first position, wherein a substantial portion of the back support member extends generally away from the first inner area, and a second position, in which the back support member lies substantially within the first inner area.

Abstract: A safety device comprising a body portion secured to the torso of a swimmer and having support straps and a handle to permit an instructor to provide support for the swimmer is disclosed. The safety device may be used for a variety of purposes, such as teaching individuals how to swim. During use, an instructor or other individual may provide support and/or guidance for the swimmer by lifting or pulling on the handle. The device may be constructed to provide both freedom of movement for the swimmer and direct contact with the instructor, thereby allowing for a safe, yet challenging, learning experience.

Abstract: A safety device comprising a body portion secured to the torso of a swimmer and having support straps and a handle to permit an instructor to provide support for the swimmer is disclosed. The safety device may be used for a variety of purposes, such as teaching individuals how to swim. During use, an instructor or other individual may provide support and/or guidance for the swimmer by lifting or pulling on the handle. The device may be constructed to provide both freedom of movement for the swimmer and direct contact with the instructor, thereby allowing for a safe, yet challenging, learning experience.