Abstract: A surgical instrument, has an end effector that includes an ultrasonic blade, and a clamp arm that moves relative to the ultrasonic blade from an opened position toward an intermediate position and a closed position. The clamp arm is offset from the ultrasonic blade to define a predetermined gap in the intermediate position between the opened position and the closed position. A clamp arm actuator connects to the clamp arm and moves from an opened configuration to a closed configuration to direct the clamp arm from the opened position toward the intermediate position and the closed position. A spacer connects with the clamp arm to inhibit movement of the clamp arm from the intermediate position toward the closed position for maintaining the predetermined gap between the clamp arm and the ultrasonic blade.

Abstract: A saliva-based testing method that bypasses the need for RNA isolation/purification is described herein. In experiments with inactivated SARS-CoV-2 virus spiked into saliva, this method has a limit of detection of 500-1000 viral particles per mL, rivalling the standard NP swab method. Initial studies showed excellent performance with 100 clinical samples. This saliva-based process is operationally simple, utilizes readily available materials, and can be easily implemented by existing testing sites thus allowing for high-throughput, rapid, and repeat testing of large populations.

Abstract: A beam limiting apparatus is provided for reducing the amount of off-focus radiation in the image-forming beam emitted from an x-ray tube assembly. The x-ray tube assembly has a housing with an x-ray port for the passage of x-rays therethrough, a mounting boss defining the x-ray port, an x-ray tube mounted within the housing and defining a glass envelope, an anode mounted within the glass envelope, and a cathode spaced relative to the anode within the glass envelope. A peripheral flange of the beam limiting apparatus is mountable to the mounting boss of the x-ray tube housing, and a radiation-absorbing body of the beam limiting apparatus projects downwardly from the peripheral flange through the x-ray port.