Abstract: A method and devices for rapid cooling of small biological samples by plunging them in a cryogenic liquid, such as liquid nitrogen, or contacting them with a cryogenic metal surface, reduce or eliminate the cold gas layer that forms above the liquid cryogens or cryogenic surfaces, producing an abrupt transition from ambient (e.g., room) temperature to the cryogen temperature as the sample enters the liquid or contacts the surface. To reduce or eliminate the effects of the cold gas layer, a flow of warm dry gas can be directed along the plunge path, for example. By removing this cold gas layer, cooling times for a 10 micron sample (the size of single cells and the smallest protein crystals now used protein crystallography) will decrease to ˜0.001 s.

Abstract: Sample mounts (10) for mounting microcrystals of biological macromolecules for X-ray crystallography are prepared by using patterned thin polyimide films (12) that have curvature imparted thereto, for example, by being attached to a curved outer surface of a small metal rod (16). The patterned film (12) preferably includes a tip end (24) for holding a crystal. Preferably, a small sample aperture is disposed in the film for reception of the crystal. A second, larger aperture can also be provided that is connected to the sample aperture by a drainage channel, allowing removal of excess liquid and easier manipulation in viscous solutions. The curvature imparted to the film (12) increases the film's rigidity and allows a convenient scoop-like action for retrieving crystals. The polyimide contributes minimally to background and absorption, and can be treated to obtain desired hydrophobicity or hydrophilicity.

Abstract: Sample mounts (10) for mounting microcrystals of biological macromolecules for X-ray crystallography are prepared by using patterned thin polyimide films (12) that have curvature imparted thereto, for example, by being attached to a curved outer surface of a small metal rod (16). The patterned film (12) preferably includes a tapered tip end (24) for holding a crystal. Preferably, a small sample aperture is disposed in the film for reception of the crystal. A second, larger aperture can also be provided that is connected to the sample aperture by a drainage channel, allowing removal of excess liquid and easier manipulation in viscous solutions. The curvature imparted to the film (12) increases the film's rigidity and allows a convenient scoop-like action for retrieving crystals. The polyimide contributes minimally to background and absorption, and can be treated to obtain desired hydrophobicity or hydrophilicity.

Abstract: A toy air gun and in particular an improved air gun for generating vortex rings are described. The gun is designed so that the path along the axis of air motion from the rear of the gun to the air exit hole is optically transparent, and contains patterns normal to this axis that assist in accurate sighting. This allows targets to be directly sighted along the axis of air or vortex ring travel. Together with improvements to ensure purely axial air motion, this dramatically increases the aiming accuracy of this class of gun and makes it suitable for target-type activities. A screen with a cylindrically symmetric pattern of openings and aiming marks prevents solid objects placed inside the gun's barrel from being projected outwards, and assists in aiming the gun. An vented safety guard at the exit end of the gun prevents large pressures from developing in the event that the gun exit is blocked while preserving the vortex ring component to the airflow.

Abstract: A toy air gun and in particular an improved air gun for generating vortex rings are described. The gun is designed so that the path along the axis of air motion from the rear of the gun to the air exit hole is optically transparent, and contains patterns normal to this axis that assist in accurate sighting. This allows targets to be directly sighted along the axis of air or vortex ring travel. Together with improvements to ensure purely axial air motion, this dramatically increases the aiming accuracy of this class of gun and makes it suitable for target-type activities. A screen with a cylindrically symmetric pattern of openings and aiming marks prevents solid objects placed inside the gun's barrel from being projected outwards, and assists in aiming the gun. An vented safety guard at the exit end of the gun prevents large pressures from developing in the event that the gun exit is blocked while preserving the vortex ring component to the airflow.