6216 results about "Electrical impedance" patented technology

A surgical system and associated method for sealing the passageway of a fluid-carrying vessel with a diameter up to 5 millimeters comprises an electrosurgical generator capable of delivering electrosurgical power, a surgical instrument electrically connected to the electrosurgical generator and adapted to transfer electrosurgical power from the electrosurgical generator to a pair of end effectors disposed at a distal end of the surgical instrument. The system also includes a power control circuit for controlling the delivery of radio frequency energy to the vessel through the end effectors, wherein the delivery of the radio frequency energy to the vessel comprises, raising the output current to a range below 1.75 Amperes RMS and the output voltage to a range below 135 Volts RMS. Radio frequency energy is applied to the vessel for a period of time while the power is held approximately constant. The flow of radio frequency energy is terminated when the impedance of the vessel being sealed reaches a predetermined level.

Methods and devices are provided for gathering impedance data related to implantable restriction devices. In general, the methods and devices can enable patients, health care providers, and others to use gathered data as a feedback mechanism to non-invasively monitor efficacy of an implantable restriction device in a patient and to identify, modify, and / or prescribe a treatment plan for the patient considering the gathered data. Impedance data can be gathered and analyzed for tissue proximate to the restriction device, e.g., a fat pad between a gastric band and the patient's stomach. Electrodes in contact with the tissue can measure an impedance of the tissue, with the impedance between the electrodes changing as the tissue reduces in size (e.g., as fat cells shrink) and / or changes configuration.

Systems, methods and apparatuses for managing ground transportation in a geographical area are disclosed. A system in accordance with the present invention comprises a graphical information systems (GIS) database that stores traffic data related to the geographical area, wherein the GIS database includes at least one node representing at least one geographical location within the geographic area and at least one arc representing at least one street within the geographic area, an impedance calculation engine, coupled to the GIS database, that determines impedances associated with the at least one node and at least one arc, and a data formatter, coupled to the GIS database and to the impedance calculation engine, for formatting incoming data used by the impedance calculation engine, wherein the impedance calculation engine updates impedances associated with the at least one node and the at least one arc based on inputs from the GIS database.

Electroporation is performed in a controlled manner in either individual or multiple biological cells or biological tissue by monitoring the electrical impedance, defined herein as the ratio of current to voltage in the electroporation cell. The impedance detects the onset of electroporation in the biological cell(s), and this information is used to control the intensity and duration of the voltage to assure that electroporation has occurred without destroying the cell(s). This is applicable to electroporation in general. In addition, a particular method and apparatus are disclosed in which electroporation and / or mass transfer across a cell membrane are accomplished by securing a cell across an opening in a barrier between two chambers such that the cell closes the opening. The barrier is either electrically insulating, impermeable to the solute, or both, depending on whether pore formation, diffusive transport of the solute across the membrane, or both are sought. Electroporation is achieved by applying a voltage between the two chambers, and diffusive transport is achieved either by a difference in solute concentration between the liquids surrounding the cell and the cell interior or by a differential in concentration between the two chambers themselves. Electric current and diffusive transport are restricted to a flow path that passes through the opening.

A method is provided for detecting a change in posture of a subject. An electrical impedance is measured between two or more sites on a stomach (20) of the subject, and an impedance signal is generated responsive thereto. The change in posture is detected by performing a posture analysis of the impedance signal. A method is also provided for treating a subject. The method includes applying an electrical signal to a site of the subject selected from the list consisting of: a colon (402) of the subject, and a distal small intestine (408) of the subject. The signal is configured to stimulate cells of the subject to increase secretion of glucagon-like-peptide-1 (GLP-1) or PYY, or to decrease secretion of ghrelin, in order to treat the subject.

A method and system for detecting microbubble formation during a radiofrequency ablation procedure. The method includes measuring an impedance of a pair of electrodes, at least one electrode in the pair of electrodes being coupled to a treatment assembly of a medical device. Radiofrequency ablation energy is transmitted between the pair of electrodes. The transmission of radiofrequency ablation energy between the pair of electrodes is terminated when after a predetermined period of time the measured impedance in either of the electrodes in the pair of electrodes is a predetermined percentage above a measured minimum impedance and a measured power is above a predetermined power threshold. An alert is generated indicating at least one of the formation and release of microbubbles proximate the pair of electrodes.

In general, in accordance with an exemplary aspect of the present invention, a low-loss interface for connecting an integrated circuit such as a monolithic microwave integrated circuit to an energy transmission device such as a waveguide is disclosed. The interface comprises an isolation wall placed between an input and output region of an integrated circuit to reduce ripple and isolate the waveguide cavity from the monolithic microwave integrated circuit circuitry. The interface further comprises a turning screw or other similar member that is configured to closely match the impedance of integrated circuit 11 with the impedance at interface 10 to further reduce loss.