ABSTRACT
OBJECTIVE: Intracardiac beating-heart procedures require the introduction and exchange of complex instruments and devices. To prevent potential complications such as air embolism and bleeding, a universal cardioport was designed and tested. METHODS: The design consists of a port body and a series of interchangeable sleeves. The port uses a fluid purging system to remove air from the instrument before insertion into the heart, and a valve system minimizes blood loss during instrument changes. RESULTS: The cardioport was tested ex vivo and in vivo in pigs (n = 5). Beating-heart procedures, such as septal defect closure and mitral valve repair, were modeled. Ex vivo trials (n = 150) were performed, and no air emboli were introduced using the port. In comparison, air emboli were detected in 40% to 85% of the cases without the use of the port-based purging system. Port operation revealed excellent ergonomics and minimal blood loss. CONCLUSIONS: A novel cardioport system designed to prevent air entry and blood loss from transcardiac instrument introduction was shown to be an enabling platform for intracardiac beating-heart surgery. The port system improves safety and facilitates further development of complex instruments and devices for transcardiac beating-heart surgery.
Subject(s)
Cardiac Surgical Procedures/instrumentation , Endoscopes , Myocardial Contraction , Animals , Coronary Artery Bypass, Off-Pump , Echocardiography, Three-Dimensional , In Vitro Techniques , Minimally Invasive Surgical Procedures/instrumentation , Sus scrofaABSTRACT
For decades, ethanol has been in use as a fuel for the storage of solar energy in an energy-dense, liquid form. Over the past decade, the ability to reform ethanol into hydrogen gas suitable for a fuel cell has drawn interest as a way to increase the efficiency of both vehicles and stand-alone power generators. Here we report the use of extremely small nanocrystalline materials to enhance the performance of 1% Rh/10% Ni@CeO(2) catalysts in the oxidative steam reforming of ethanol with a ratio of 1.7:1:10:11 (air/EtOH/water/argon) into hydrogen gas, achieving 100% conversion of ethanol at only 300 degrees C with 60% H(2) in the product stream and less than 0.5% CO. Additionally, nanocrystalline 10% Ni@CeO(2) was shown to achieve 100% conversion of ethanol at 400 degrees C with 73% H(2), 2% CO, and 2% CH(4) in the product stream. Finally, we demonstrate the use of biological templating on M13 to improve the resistance of this catalyst to deactivation over 52 h tests at high flow rates (120 000 h(-1) GHSV) at 450 degrees C. This study suggests that the use of highly nanocrystalline, biotemplated catalysts to improve activity and stability is a promising route to significant gains over traditional catalyst manufacture methods.
Subject(s)
Bacteriophage M13/chemistry , Bioelectric Energy Sources , Crystallization/methods , Ethanol/chemistry , Hydrogen/chemistry , Nanostructures/chemistry , Nanostructures/ultrastructure , Viral Proteins/chemistry , Catalysis , Hydrogen/isolation & purification , Macromolecular Substances/chemistry , Materials Testing , Molecular Conformation , Nanotechnology/methods , Particle Size , Surface PropertiesABSTRACT
This paper describes an accurate, economical, and portable device that helps to locate the position of an endotracheal tube (ETT) in situ. The device uses an array of magnetic field sensors to detect an anomaly in magnetic field caused by magnet embedded near the cuff of an ETT, and displays an intuitive map of relative magnetic field intensity under the sensor area. The device provides real-time feedback of the position to a clinician, so that corrective measures can be taken if the ETT is determined to be outside of normal positioning with respect to the patient's airway. Variations of the proposed design are suitable for continuous monitoring.
