Abstract: An optical head assembly for sue with a stringed musical instrument, the vibrations of the strings causing a light beam to be modulated in accordance with the frequency of the vibrating strings. The modulated light output, produced by the relative motion between two adjacent grates, is coupled to a device with converts the modulated light beam to a corresponding modulated electrical signal which, in turn, is coupled to an amplifier associated with the instrument.

Abstract: An optical head assembly for use with a stringed musical instrument, the vibrations of the strings causing a light beam to be modulated in accordance with the frequency of the vibrating strings. The modulated light output, produced by the relative motion between two adjacent grates, is coupled to a device with converts the modulated light beam to a corresponding modulated electrical signal which, in turn, is coupled to an amplifier associated with the instrument.

Abstract: In preferred embodiments, a fast spin echo imaging technique is provided that is insensitive to violations of the Carr Purcell Meiboom Gill (CPMG) condition. Diffusion gradients disrupt the CPMG condition, and, hence, the present fast spin echo method is compatible with diffusion measurements and diffusion weighted imaging. The preferred embodiments of the present technique involve splitting of spin echoes into echo pairs. Spin echoes are split by adjustment (in magnitude or duration) of an initial readout gradient pulse. A train of echo pairs is captured. A first image is constructed using the first echoes of each pair. Also, a second image is constructed using the second echoes of each pair. Hybrid radial Cartesian methods are used for constructing the first and second images. The first and second images are constructed independently of one another. Independent image construction renders the method insensitive to violation of the CPMG condition. Finally, the two images are combined to form a final image.

Abstract: In preferred embodiments, a fast spin echo imaging technique is provided that is insensitive to violations of the Carr Purcell Meiboom Gill (CPMG) condition. Diffusion gradients disrupt the CPMG condition, and, hence, the present fast spin echo method is compatible with diffusion measurements and diffusion weighted imaging. The preferred embodiments of the present technique involve splitting of spin echoes into echo pairs. Spin echoes are split by adjustment (in magnitude or duration) of an initial readout gradient pulse. A train of echo pairs is captured. A first image is constructed using the first echoes of each pair. Also, a second image is constructed using the second echoes of each pair. Hybrid radial Cartesian methods are used for constructing the first and second images. The first and second images are constructed independently of one another. Independent image construction renders the method insensitive to violation of the CPMG condition. Finally, the two images are combined to form a final image.

Abstract: A method and a system for acquiring diffusion magnetic resonance images with compensation of the effects of eddy currents induced by the diffusion weighting (DW) gradient pulses. Prescan data are first acquired using the same DW sequence to be used for imaging. The prescan data are used to obtain eddy current parameters that model the effects of DW-induced eddy currents under the exact conditions under which DW images are to be acquired. The DW imaging sequence is then slightly modified according to the eddy current parameters and used to acquire DW image data with the effects of DW-induced eddy currents compensated.

Abstract: A remote intrusion detection radio appliance includes a housing having a passive motion detector and related circuitry to monitor and warn of unwanted intrusions, by operating an external radio unit or cellular telephone plugged into the appliance. The appliance, when activated, broadcasts an audio output and then monitors an area in which it is located by audio and/or video for an intruder.

Abstract: In one aspect, the present invention provides kinetic spectrophotometers that each comprise: (a) a light source; and (b) a compound parabolic concentrator disposed to receive light from the light source and configured to (1) intensify and diffuse the light received from the light source, and (2) direct the intensified and diffused light onto a sample. In other aspects, the present invention provides methods for measuring a photosynthetic parameter, the methods comprising the steps of: (a) illuminating a plant leaf until steady-state photosynthesis is achieved; (b) subjecting the illuminated plant leaf to a period of darkness; (c) using a kinetic spectrophotometer of the invention to collect spectral data from the plant leaf treated in accordance with steps (a) and (b); and (d) determining a value for a photosynthetic parameter from the spectral data.

Abstract: The present invention provides methods for measuring a photosynthetic parameter. The methods of the invention include the steps of: (a) illuminating a plant leaf until steady-state photosynthesis is achieved; (b) subjecting the illuminated plant leaf to a period of darkness; (c) using a kinetic spectrophotometer or kinetic spectrophotometer/fluorimeter to collect spectral data from the plant leaf treated in accordance with steps (a) and (b); and (d) determining a photosynthetic parameter from the spectral data. In another aspect, the invention provides methods for determining the physiological state of a plant.

Abstract: A magnetic resonance imaging (MRI) method is disclosed for generating and identifying water and fat separated MR images. Image data is first acquired to obtain two echo images with the water and fat signals orthogonal in the first echo image, and parallel/anti-parallel in the second echo image. The effect of background field inhomogeneties are removed, and water and fat images are separated from each other. The separated water and fat images are identified according to the difference of their precessing frequencies.

Abstract: A magnetic resonance imaging (MRI) method is disclosed for generating and identifying water and fat separated MR images. Image data is first acquired to obtain two echo images with the water and fat signals orthogonal in the first echo image, and parallel/anti-parallel in the second echo image. The effect of background field inhomogeneties are removed, and water and fat images are separated from each other. The separated water and fat images are identified according to the difference of their precessing frequencies.

Abstract: A magnetic resonance imaging method and apparatus gathers NMR image data over a sequence of measurement cycles. First magnetic gradient pulses are superimposed on a nominally static magnetic field to selectively address NMR RF excitations for at least one predetermined volume and second magnetic gradient pulses are superimposed on the static magnetic field at other times in a measurement cycle. At least one further of the measurement cycles is performed during which at least one of the second gradient pulses is omitted so as to produce calibration data representative of the magnetic field then existing in the predetermined volume. The calibration data is used to produce MRI data compensated for phase angle errors which otherwise would be present due to undesirable changes with respect to time in the magnetic field actually present in said predetermined volume.

Abstract: In one aspect, the present invention provides kinetic spectrophotometers that each comprise: (a) a light source; and (b) a compound parabolic concentrator disposed to receive light from the light source and configured to (1) intensify and diffuse the light received from the light source, and (2) direct the intensified and diffused light onto a sample. In other aspects, the present invention provides methods for measuring a photosynthetic parameter, the methods comprising the steps of: (a) illuminating a plant leaf until steady-state photosynthesis is achieved; (b) subjecting the illuminated plant leaf to a period of darkness; (c) using a kinetic spectrophotometer of the invention to collect spectral data from the plant leaf treated in accordance with steps (a) and (b); and (d) determining a value for a photosynthetic parameter from the spectral data.

Abstract: A method and apparatus for producing water-dominant and fat-dominant MR signal data for use in constructing separate images from single-scan single-point Dixon MRI sequences is disclosed. The effects of field inhomogeneities are removed by quantitating the signal phase by taking the argument of the MR signal multiplied by itself. A region-growing algorithm guided by a polynomial model is used to unwrap the phase which is then used to separately generate water-pixel data and fat-pixel data for producing separate images. The invention can be used for constructing images from both 2-D and 3-D spin-echo and/or field-echo acquisitions.

Abstract: A high precision alignment apparatus is provided that utilizes a semiconductor laser device, such as a laser diode, to provide a source laser beam. The alignment apparatus permits the division of a pair of beam components from the source laser beam useful for either linear or planar alignment. A centroid measurement between the beam components provides a corrected reference point that accounts for the inherent instability of the source laser beam to yield a high level of alignment accuracy. For linear alignment purposes, the beam components are collinearly directed. In the alternative, for planar alignment purposes, the beam components may be either collinear or directed in opposite directions, and rotated to sweep respective planar regions. The laser alignment apparatus is capable of providing a level of accuracy heretofore achievable only with gas lasers, while maintaining the economical attributes of commercial semiconductor laser diodes.

Abstract: An automatic circuit controller for cooking food interposed between electrodes connected with a source of AC by electrical resistance in which the resistance increases until the food is cooked and rapidly declines is formed by a current switching element in series in one wire of the AC source and a current sensing element in series in another wire of the AC source. The sensed current is rectified, reduced in voltage, converted from analog to digital and applied to a microprocessor connected with the switching element for controlling the current applied to the food by delaying the time into every half cycle in response to current measuring circuitry and a zero crossing detector for triggering the switching element on. The microprocessor detects the current peak of electrical resistance of the food and stops the cooking action when the current declines to a predetermined percent of the peak.

Abstract: A method and apparatus for obtaining three MRI image data in a single data acquisition TR interval for use in constructing separate water and fat images by appropriate processing of the three images data is disclosed. The three image data are obtained in one exemplary embodiment by sandwiching a spin echo between two field echoes. The invention can also be used for multiple-echo and multiple-slice 3D scans.

Abstract: A high precision alignment apparatus is provided that utilizes a semiconductor laser device, such as a laser diode, to provide a source laser beam. The alignment apparatus permits the division of a pair of beam components from the source laser beam useful for either linear or planar alignment. A centroid measurement between the beam components provides a corrected reference point that accounts for the inherent instability of the source laser beam to yield a high level of alignment accuracy. For linear alignment purposes, the beam components are collinearly directed. In the alternative, for planar alignment purposes, the beam components may be either collinear or directed in opposite directions, and rotated to sweep respective planar regions. The laser alignment apparatus is capable of providing a level of accuracy heretofore achievable only with gas lasers, while maintaining the economical attributes of commercial semiconductor laser diodes.

Abstract: Methods and apparatus for correcting image artefacts caused by variations in the main magnetic field of an MRI system are disclosed, particularly for MRI with steady-state spin precession. For field correction in MRI with steady-state spin precession, the effects of the field changes can be corrected by quantifying the time course of the field drifts by repeated acquisition of the zero k-space lines. The change in the phase between consecutive zero k-space lines is used as an indicator of field variation and for correction of associated image artifacts. By using for field correction the zero k-space lines acquired using the imaging sequence itself, the steady-states of spin precession are undisturbed throughout the MRI data acquisition.

Abstract: A sealing apparatus for applying seals, such as valves, over a pressure relief passage of a container. Displaceable retention members, positioned next to a platen having an applicator surface, releasably secure one or more seals adjacent the applicator surface prior to attachment to the container. A seal attachment element moves the applicator surface toward and into a seal attachment position adjacent the container. As the applicator surface moves, the displaceable retention members release to, in turn, effectuate attachment of the seals over the pressure relief passage. A retraction element operatively attached to the platen causes return movement of the applicator surface and, in turn, return of the displaceable retention members back into a seal retaining position.

Abstract: At least one imaging parameter (e.g., the repetition interval TR or the initial nutation angle .theta.) is varied during the course of a single MR image sequence. This variation in at least one imaging parameter is preferably controlled so as to increase the contrast and signal-to-noise ratio of lower spatial frequency image components. For example, by using longer TR intervals (or smaller initial nutation angle .theta.) during lower spatial frequency phase encoding sub-sequences, relatively more signal is gathered from NMR nuclei having long T1 parameters thus providing a resultant image with many characteristics of a much longer overall sequence (e.g., one using uniform relatively long TR intervals for all spatial frequency phase encoding sub-sequences).