Abstract: An adjustable resistance valve for a cerebrospinal fluid shunt system includes an actuator for allowing the selection of the resistance to flow of the valve, a device for selecting at least one passage traversing across the valve, and a resistance system. The resistance system includes a set of passages each defining a different resistance to flow. The passages are disposed in a circle facing the selecting device such as to guide the flow of the cerebrospinal fluid traversing the passage of the selecting device through the selected passage of the resistance system. The actuator enables one to change the relative position of the selecting device with respect to the resistance system by a rotational movement to select the desired resistance of the valve.

Abstract: A micro valve and a method for setting or actuating a micro valve for use in fluidic applications includes cooling an array of actuating members made of Shape Memory Alloy (SMA) material. The SMA material is cooled to a temperature equal to or below the temperature at which a transformation from austenitic to martensitic state occurs so that the entire array of SMA actuating members is either fully or partially in the martensitic state. At least one of the actuating member is selected to correspond to a pre-determined opening pressure or flow resistance. Each of the actuating members are heated individually, except the previously selected one, to a temperature equal to or above the temperature at which a transformation from the martensitic state to the austensitic state occurs.

Abstract: Nuclear magnetic resonance spectroscopy catheter probe comprising a permanent magnet arrangement (1,2,3,4) for generating a static magnetic field of suitable intensity and homogeneity for analysing a sample of fluid flowing into a catheter (6) traversing the permanent magnet arrangement. The probe further comprises an arrangement of electronic circuits (8,9) responsible for the excitation and detection of the nuclear magnetic resonance signal and at least one coil (7) to expose the fluid sample to the excitation signal and to collect the returned nuclear magnetic resonance signal.

Abstract: An implantable nuclear magnetic resonance spectrometer for measuring the chemical composition of a fluid or for measuring the flow rate of the fluid. The spectrometer includes a housing and a catheter traversing across the housing so that a fluid external to the housing may flow through the catheter within the housing. A permanent magnet is disposed within the housing and generates an intense homogenous magnetic field in the vicinity of the catheter. An electronic circuit is disposed within the housing for detecting and formatting a nuclear magnetic resonance excitation signal. An excitation coil is connected to the electronic circuit and is disposed about the catheter to expose the fluid within the catheter to the excitation signal and to collect the nuclear magnetic resonance excitation signal.