Abstract: Transcutaneous electrical nerve stimulation is applied to the patient, as though electrocardiograph monitoring is not being practiced. The EKG signals are preprocessed through a selective sample and hold module, which performs amplification, comparison with selective frequency and amplitude standards (as by differentiation) and temporary holding of EKG signals at such time as the transcutaneous nerve stimulating pulses are occurring, as sensed against the frequency and amplitude criteria. In the absence of transcutaneous stimulation signals, EKG signals are coupled directly through for conventional EKG processing.

Abstract: A curved faced, disc shaped transducer and an oppositely facing, circular angularly disposed mirror form the transmission and reception path of a mechanical sector scan imaging system. The transducer and mirror are mounted on a common axis, and a shaft upon which the mirror is affixed oscillates about that axis. Through a belt drive mechanism, a motor provides the oscillating motion, in turn scanning the ultrasound beams through the subject by virtue of the mirror motion. An optical encoder records positional information from the motor, for coordination of the mirror oscillation with transducer signals, and thereby for the assembly of a composite image.

Abstract: A novel method is disclosed for detecting and controlling the flow rate of a perturbed, droplet-forming stream in an electrostatic particle sorting apparatus. Detection apparatus is located at two points along the stream, at a first particle sensing point for sensing the presence of particles within a core portion of the stream, and at a second downstream point, preferably the stream breakpoint, for sensing light scatter and extinction characteristics which are proportional to the surface characteristics of the sheath portion of the stream. Changes in phase shift, pulse width, duty cycle, pulse area, or breakpoint location are detected by analyzing these sheath surface-related characteristics. An error signal is produced in response to such changes which drives an electromechanical fluid flow regulator to increase or decrease the fluid flow rate in a direction which tends to minimize the error signal. The flow rate is thus maintained at a reference flow rate setting.

Abstract: A sample of whole blood is stained with an acridine orange reagent, and is analyzed rapidly, a cell at a time, in a flow cytometry system having a sample stream dimension in the range of expected red cell dimensions. Red florescence and forward scatter data is utilized first to discriminate a cell from noise, and then to distinguish platelets from reticulocytes and red cells. The red cell and reticulocyte data is subjected to a correction such as rotational coordinate shift, and the shifted data are, by means of statistical procedures, utilized to determine threshold criteria separating red cells from reticulocytes, and to enumerate the cells on that basis.

Abstract: In order to initiate the charging of droplets at a specific point in time with respect to the formation of those droplets in an electrostatic flow sorting system, the charge phase of the system of the present invention is continuously and automatically adjusted by droplet break point monitoring. The charge phase is therefore flow rate and fluid velocity independent. The break point is monitored by a light source which is focused onto the jet stream at the droplet formation break point, or close to it, and the modulation of light caused by the scatter induced by the sheath stream portion as it passes the focused beam of light is detected via the use of a suitable electro-optical detector. From the output of the electro-optical detector, after appropriate signal conditioning, an electrical wave form is obtained which shape depends upon the shape of the fluid column passing the focus beam.

Abstract: A novel method and apparatus for automatically setting the time delay for relatively charging droplets in an electrostatic particle sorting system is disclosed. By utilizing a movable sheath sensing means for sensing the light scatter and extinction of this stream, the flow rate and distance to breakpoint are automatically measured and used to calculate and set the timing delay circuitry. This insures that droplet charging at the breakpoint will occur synchronously to produce selective relative charging of those droplets containing particles to be sorted.

Abstract: A method for the measurement of fluid velocity and fluid flow rate is described which may be applied to a system in which fluid is caused to exit through an orifice to form a free jet. Optical as well as fluidic properties of the jetting fluids are used to determine the mean velocity of the jet between its point of exit from the orifice and at least a preselected detection point. From the mean velocity determination, the fluid flow rate may also be determined. A marker signal perturbation is applied to the jetting fluid at the orifice, and is detected downstream at a stream sensing point which is located a preselected distance from that orifice.

Abstract: A novel method for positioning the point of droplet formation in the jetting fluid of an electrostatic sorting device is disclosed. The formation of the uniform droplets is carried out via the application of vibrational energy inparted by a transducer to a jetting laminar flow stream. Previously sensed particles contained within the core portion of the laminar stream are subsequently sorted from the stream as part of a subsequently formed droplet. The disclosed method uses the dependency of the droplet formation point on the amplitude of the wave form applied to the transducer and the modulation of this amplitude to control the droplet formation point distance. The position of the droplet formation point is detected via the use of a light source and photodetector focused on the jetting stream at the position at which the droplet formation point is to be located, and a method for automatically maintaining the breakpoint at that position is described.

Abstract: A novel method and system are disclosed for detecting the breakpoint of a perturbed flow stream. The scattering and extinction of light caused by a perturbed stream at a preselected flow stream sensing point therealong is measured to produce a real time waveform proportional thereto. The real time waveform is differentiated to produce a differentiated waveform, which is then selectively monitored to distinguish a waveform exhibiting substantially three (positive and negative) peaks per cycle, whereby such detection indicates that at least a portion of the breakpoint region of said flow stream corresponds with said flow stream sensing point. In order to align the stream sensing point with respect to a preselected point within the breakpoint region of the flow stream, the breakpoint region of the stream is caused to move with respect to the stream sensing point until the breakpoint pulse width of one of the peaks corresponds with a preselected pulse width reference.

Abstract: Encoded data is sequentially read into a shift register having a number of stages larger than the largest inter-scan "void" or "hole" to be filled. A priority encoder determines the length of the void to be filled, and the amplitude difference of successive scan data samples is evaluated. For each display picture element in the void, a weighting select PROM determines an appropriate weighting factor, based on the size of the void to be filled. Separate positive differential and negative differential memories are thereby energized to produce, for each display picture element in the hole, a simulated display picture data element.

Abstract: Ultrasound breast scanning and diagnosis is achieved by suspending the breast in a water pool, in which is immersed a wide aperture transducer/lens assembly. The water path is defined by two separate segments, an upper one, into which the breast is suspended, contained by a flexible sonically transparent bag member, and the lower being contained in a longitudinally movable tank which is filled to contact with the bag member portion protruding into the tank.

Abstract: Images and respectively associated timing marks are arrayed, as phototransparencies, about a disk. The disk is rotated and the timing marks are sensed. Display occurs either in two-dimensional fashion, such as in a television system, or in three-dimensional fashion such as in a semitransparent full image projection. Associated logic circuitry determines whether the full 3-D transparency is to be produced, in which case all images on the disk are to be illuminated, or whether swim through will occur, either on an image at a time or on a "ham slice" projection basis.

Abstract: The patient is prepared for surgery in conventional fashion, but further including the administration of sterile transcutaneous electrodes proximal to the enervation loci of the prospective incision. Electrical stimulation is commenced, an anesthetic agent is administered, and the electrical stimulation is readjusted to the highest levels attainable short of tetany. The surgery proceeds with substantially reduced maintenance quantities of anesthetic.

Abstract: Fluorescence volume exclusion signals are utilized to evaluate cell volume. Cells are suspended in a medium which is furnished with a fluorescent dye which neither penetrates nor adheres to the cells. Cells are analyzed by an optical flow cytometer, with illumination which causes the dye medium to fluoresce. Passage of a cell through the sensing zone therefore reduces the amount of fluorescent medium being illuminated, and proportionally reduces the fluorescence output signal. Fluorescence volume exclusion pulse height and area are related to cell volume.

Abstract: Specified subclasses of blood cells, such as of lymphocytes, are automatically identified based on utilization of antigenic determinants on the cell surface, their reactivity with antibodies which fluoresce under known circumstances, and utilization of principles of flow cytometry. A blood sample is first incubated with a reagent including antibodies to the lymphocyte subclass to be identified, the antibodies being directly or indirectly made fluorescently responsive to particular light (e. g. argon ion laser). The sample is illuminated, a cell at a time, by such focused coherent light, and forward light scatter, right angle light scatter, and fluorescence are detected and used to identify and enumerate cells of the specified subclass.

Abstract: In an ultrasound imaging system employing a moving or oscillating transducer, actual transducer position is detected periodically, rather than continuously. A magnet is caused to oscillate with the transducer, and periodic alignment of the magnet with a fixedly mounted Hall effect switch provides synchronization data for sonic pulse generation, pulse-echo receipt, and image assembly and display.

Abstract: A partially disposable, partially reusable polarographic sensor includes a fixed membrane and gel electrolyte in the disposable portion, and includes all electrical/metallic parts in the reusable portion. The disposable portion comprises a housing having a flow chamber for fluids to be monitored, adjacent to which is the membrane. Behind the membrane is the gel electrolyte, and a screw structure for engaging the reusable part. In turn, the reusable part employs a matable screw portion, and a fixed, coaxial anode-cathode assembly, which when mounted to the disposable portion, engages the membrane.

Abstract: A B-scan pulse echo ultrasound system produces a real time image of a body area under inquiry, and an aspiration needle is inserted directly into that area. The needle carries a small, omni-directional ultrasound transducer, electrically connected through the needle to transponder electronics. Incident pulses from the imaging transducer to the omni-directional transducer are sensed at the latter, and the position thereof is inserted into the image either by generation of a return signal from the needle point, or through delay logic and subsequent production of a composite.

Abstract: A disposable electrode includes a fabric backing and a conductive mesh layer laminated thereto. A conductive polymer adhesive interfaces the conductive mesh with the skin of the patient. In order to promote uniform current density, connection to external apparatus occurs by means of a stranded wire which penetrates the mesh from the top and extends laterally in opposite directions along the electrode, intermediate the mesh and the adhesive.

Abstract: A disposable electrode includes a fabric backing and a conductive mesh layer laminated thereto. A conductive polymer adhesive interfaces the conductive mesh with the skin of the patient. In order to promote uniform current density, connection to external apparatus occurs by means of a stranded wire which meets the mesh at a point and extends laterally therefrom along the electrode, intermediate the mesh and the adhesive.