摘要:
There are disclosed apparatus and methods for replacing a percutaneous cable in connection with a vascular device. In an embodiment, the apparatus includes a distal disconnect coupler, a distal connector portion of the cable configured for removable connection with the distal disconnect coupler, and a connector cap configured for removable connection with the distal disconnect coupler and for tunneling through skin and tissue. In one embodiment, a method of repositioning a percutaneous cable in connection with a vascular device includes providing the cable with a distal disconnect coupler, disconnecting the cable at the distal disconnect coupler, attaching a connector cap to the distal disconnect coupler, removing the percutaneous cable from a first exit site, tunneling the connector cap together with the distal disconnect coupler through skin and tissue to form a new exit site, disconnecting the connector cap, and connecting the cable to the distal disconnect coupler.
摘要:
There are disclosed apparatus and methods for replacing a percutaneous cable in connection with a vascular device. In an embodiment, the apparatus includes a distal disconnect coupler, a distal connector portion of the cable configured for removable connection with the distal disconnect coupler, and a connector cap configured for removable connection with the distal disconnect coupler and for tunneling through skin and tissue. In one embodiment, a method of repositioning a percutaneous cable in connection with a vascular device includes providing the cable with a distal disconnect coupler, disconnecting the cable at the distal disconnect coupler, attaching a connector cap to the distal disconnect coupler, removing the percutaneous cable from a first exit site, tunneling the connector cap together with the distal disconnect coupler through skin and tissue to form a new exit site, disconnecting the connector cap, and connecting the cable to the distal disconnect coupler.
摘要:
Molten droplets of a metal fuel, such as aluminum, are dispersed into air or water for a reaction releasing energy for military or other purposes. In one warhead embodiment, a cylinder of solid metal is disposed within a ceramic heat insulator; heaters of thermite-like material are embedded in the metal; and an explosive dispersing charge is disposed around or at one end of the cylinder. On activation, the heaters are ignited to melt the metal, and the charge then detonated to disperse droplets of the molten metal. In a related embodiment, the metal and heaters are within a containment having an atomizing nozzle at one end and, oppositely of the metal from the nozzle, a piston and gas generator. When the metal is melted, the gas generator is activated to expel molten metal droplets from the nozzle. The fuel may be pressed particles heated below the melting point and then dispersed by a charge providing enough heat to melt the particles; may be a single component, fuel-rich thermite compound; and may include droplet surface tension reducing additives. Advantages are that the weight and volume of a warhead do not include explosives, binders, and underwater-use oxidizers employed with fuel particles in conventional energetic materials. A warhead may thus have greater density for effective penetration; and, since the fuel is not incorporated in an explosive, dispersing charges can be removed until use, and metal fuels hazardous when incorporated in an explosive can be used.
摘要:
Molten droplets of a metal fuel, such as aluminum, are dispersed into air or water for a reaction releasing energy for military or other purposes. In one warhead embodiment, a cylinder of solid metal is disposed within a ceramic heat insulator; heaters of thermite-like material are embedded in the metal; and an explosive dispersing charge is disposed around or at one end of the cylinder. On activation, the heaters are ignited to melt the metal, and the charge then detonated to disperse droplets of the molten metal. In a related embodiment, the metal and heaters are within a containment having an atomizing nozzle at one end and, oppositely of the metal from the nozzle, a piston and gas generator. When the metal is melted, the gas generator is activated to expel molten metal droplets from the nozzle. The fuel may be pressed particles heated below the melting point and then dispersed by a charge providing enough heat to melt the particles; may be a single component, fuel-rich thermite compound; and may include droplet surface tension reducing additives. Advantages are that the weight and volume of a warhead do not include explosives, binders, and underwater-use oxidizers employed with fuel particles in conventional energetic materials. A warhead may thus have greater density for effective penetration; and, since the fuel is not incorporated in an explosive, dispersing charges can be removed until use, and metal fuels hazardous when incorporated in an explosive can be used.
摘要:
A heart-assist system and a method for operating same are described in which a pump is connected to a ventricle to receive output therefrom. An actuator operates to cause the pump to conduct a fill cycle in which it receives output from the ventricle to which it is connected, and to conduct an eject cycle in which the contents of the pump are expelled. The time of initiation of at least one of the fill cycle and the eject cycle is varied in relation to systole of the ventricle to which the pump is connected to thereby vary the loading of the ventricle. Several techniques for detecting termination of systole are described including a compliant stop on the pump.
摘要:
Molten droplets of a metal fuel, such as aluminum, are dispersed into air or water for a reaction releasing energy for military or other purposes. In one warhead embodiment, a cylinder of solid metal is disposed within a ceramic heat insulator; heaters of thermite-like material are embedded in the metal; and an explosive dispersing charge is disposed around or at one end of the cylinder. On activation, the heaters are ignited to melt the metal, and the charge then detonated to disperse droplets of the molten metal. In a related embodiment, the metal and heaters are within a containment having an atomizing nozzle at one end and, oppositely of the metal from the nozzle, a piston and gas generator. When the metal is melted, the gas generator is activated to expel molten metal droplets from the nozzle. The fuel may be pressed particles heated below the melting point and then dispersed by a charge providing enough heat to melt the particles; may be a single component, fuel-rich thermite compound; and may include droplet surface tension reducing additives. Advantages are that the weight and volume of a warhead do not include explosives, binders, and underwater-use oxidizers employed with fuel particles in conventional energetic materials. A warhead may thus have greater density for effective penetration; and, since the fuel is not incorporated in an explosive, dispersing charges can be removed until use, and metal fuels hazardous when incorporated in an explosive can be used.
摘要:
A pumping system for assisting either or both ventricles of the heart. In one embodiment, separate devices are provided for each ventricle. In another embodiment, one device provides both right and left pumping. The pumping system is small, efficient, atraumatic, and fully implantable. In addition, the pumping system can provide pulsatile flow during systole. The ventricular assist device includes an actuator plate between a pair of serially connected pumping chambers that operate in a two-stroke mode, specifically a power stroke and a transfer stroke. The ventricular assist device also includes an electromagnetic drive system that provides adjustment to the pump pressure according to the current through an electromagnet. For the pumping system, springs provide a “spring force” on the actuator plate that is towards the high-pressure pump chamber. The bias force allows the springs to store and deliver energy from the electromagnetic drive system to provide better utilization of the pump components, and to reduce the pump size and consumption of electricity.
摘要:
An implantable ventricular assist device (VAD) has a small size to provide full-implantable capabilities. The VAD has two variable-volume chambers and an actuator for expelling blood from the chambers in sequence and to a common outlet, thus operating as a positive-displacement pump. The variable-volume chambers may be flexible sacs and the pump is operable at a substantially continuous flow, such as during the systolic phase of the assisted ventricle. A method of operation includes operating the pump at a first frequency during systole and a second lower frequency during diastole. The VAD pump includes a pair of coils housed within a frame and disposed in a spaced relationship to generate a coil flux through a pair of poles. A plate including an armature and a magnet is disposed within the frame such that the armature is between the poles and the magnet is between the coils. Gaps are defined between the armature and each of the poles and the coil flux displaces the armature across the gap. The coil flux follows a donut-shaped path including the frame, one of the poles, one of the gaps, the armature, the other the gap, and the other the pole, and no coil flux passes through the magnet. The magnet is not subject to depolarization and may be made substantially smaller than those of conventional devices. The magnet generates a bias flux that offsets a portion of the coil flux around the frame. A spring may be provided to counteract the unstable action of the bias magnet. The volume of the chambers is a fraction of the ventricular volume, and may be about 20 ml. To pump a typical 80-ml volume of a left ventricle, the controller may activate the coils four times during systole, or once every 40 msec.
摘要:
An actuator is described for use in a pump having a pump chamber whose contents are expelled by movement of a pair of pusher plates toward one another. The actuator includes opposed solenoid armatures which are operable for movement between open and closed positions. The armatures are each operatively connected to an associated pusher plate by a main spring which is attached at one end to the back end of the armature, extends through a front-to-back slot in an armature core, and is connected at its opposite end to the pusher plate. A pair of preload springs carried on each armature and disposed on either side of the associated main spring acts to hold the main spring in a prestressed condition prior to solenoid actuation. With closure of the armatures, and with the sac still in an expanded condition, the main springs are disengaged from the associated preload spring and placed in a more stressed, more planar configuration, with the increased stress in each main spring being relieved by movement of the pusher plates toward one another.