Minnesota Mining and Manufacturing Company

Josef A Graessle

Werner R Schwarz

Theo N Wildt

John C Schultz

Peter J Zarembo

William E Foltz

Steven S Kirckof

Brian Kirk

Steven P Floeder

Frederick M Waltz

A magnetic security marker of an article surveillance system is deactivated by first determining the status of the marker by exposing it to the interrogating field. If the marker is active, a deactivation field is applied to the marker. The marker is again interrogated using the interrogating field and, if an active marker is detected, an incrementally increased deactivation field is applied. The marker is continually interrogated and, as long as an active marker is detected, the intensity of the field is incrementally increased until the field reaches a level effecting deactivation.

Electro-magnetic desensitizer

An apparatus for counting microorganism colonies on at least one disposable microorganism culturing medium having a substantially planar substrate. The apparatus is adapted to interact with a cassette holding a number of similar substrates at once. The apparatus includes an imaging device capable of detecting colonies on the substantially planar substrate, a cassette positioning device for moving the cassette so that the substrates supported within the cassette are moved sequentially into a predetermined position relative to the imaging device, and an ejecting device for ejecting a substantially planar substrate in turn from the cassette when that substrate is in the predetermined position from the cassette and into an imaging position adjacent the imaging device. Suitable cassettes and a method for counting colonies on substrates supported within a cassette are also disclosed.

Cassette for disposable microorganism culturing media and automated

A self-contained electronic test pack utilizes parametric measurments to determine the efficacy of a sterilization cycle. The electronic test pack is placed within a sterilization chamber and monitors and records environmental parameters at two predetermined locations during the sterilization cycle. More specifically, the test pack provides a challenging medium to challenge sterilant penetration to a first location and measures a first environmental condition at that location, and measures a second environmental condition within the sterilization chamber. The test pack records data associated with the first and second environmental conditions as well as time data from a timer within the test pack. The test pack may further process the data to determine whether adequate sterilant penetration has been achieved, or may transfer data to external devices to process the data.

Electronic test pack using parametric measurements for sterlizers

The present invention relates to a method and apparatus for counting the number of microorganism colonies present on a disposable microorganism culturing device having a substantially planar substrate. The preferred apparatus of the present invention includes an LED bar illuminating the surface of the substrate and a linear array of SELFOC lenses which focus the light reflected off of the substrate onto a linear CCD sensor array. The CCD sensor array is connected to a microprocessor which analyzes the raster-scanned data using the preferred algorithm. The preferred algorithm uses the sigma-shaped neighborhood for image processing. The preferred algorithm passes the sigma region across the image in a raster-scanned order to detect object starts and merges which yield a colony count for a scanned microorganism culturing device.

Technique to count objects in a scanned image

An apparatus and method for detecting fluorescence of an unknown target material. An energy source arranged to excite both the target material and the reference material at approximately the excitation wavelength. A reference detector and a target detector are optically arranged to be responsive to light emitted from the reference material and the target material, respectively, at approximately the fluorescing wavelength. A reference measurement means generates a reference output in response to the reference detector in order to determine the amount of fluorescence generated by the reference material. A target measurement means generates a target output in response to the target detector means in order to determine the amount of fluorescence generated by the target material. Reference calibration means varies the electrical voltage supplied to the energy source and calibrates the reference output. Target calibration means calibrates the target output in response to a known target material.

Method and apparatus for detecting fluorescence

The invention is related to a process of deactivating a magnetic security marker of an article surveillance system, wherein the security marker is detected by simulating conditions normally present in such a system, e.g., by creating between a transmitter and a receiver a sinewave electromagnetic field and the deactivating the security marker by means of the electronically switchable magnetizing apparatus in response to the detection of the magnetic field which corresponds to the magnetization of the security marker in the surveillance zone. It is the object of the invention to enable the magnetic security marker to be deactivated using any alternating power line. To this end, the magnetic system is automatically connected to a power line without circuit change when the security marker is detected. The magnetizing apparatus gradually builds up a magnetic field by rectifying the flow current, monitoring it by a current sensor and increasing it at each change of phase until the current reaches a level to which the sensor is set as effecting deactivation. Thereafter, the magnetizing apparatus is electronically disconnected from the power line.

Growing community of inventors

Kaarst, Germany

Josef A Graessle