Abstract: An improved instrument for and method of performing a transurethral balloon dilatation procedure of the prostate is disclosed. The instrument includes a hollow catheter comprising a shaft having at least its distal end portion made of an optically transparent material, and a substantially non-compliant, inflatable, optically transparent balloon attached at the distal end portion of the catheter and sized to dilate the prostatic urethra so as to post-operatively open that passageway. The catheter is provided with at least one suitable marking so as to indicate at least the location where the proximal end of the balloon is attached to the catheter body. Preferably, the marking is provided at a location that when positioned at visible landmarks, preferably the external sphinter, or the apex or verumontanum of the prostate, the balloon will be correctly positioned relative to the external sphincter muscle at the apex of the prostate.

Abstract: An assay filter unit where the filter of the unit is sealed into the body of the unit to prevent any passage of material to be assayed round the edge of the filter but is removable by breaking out a filter support grid along a predetermined line of weakness, together with the filter, for assay of material retained on the filter.

Abstract: An instrument for and method of effectively treating the prostatic urethra so as to relieve the symptoms associated with an enlarged urethra is disclosed. The tissue of at least selected portions of the prostate are compressed (preferably with a balloon inserted into the prostatic urethra so as to enhance hemostasis) and at least selected portions of the compressed tissue are directly irradiated (preferably with a laser beam transmitted from within the passageway in selected radial directions and moved along the prostatic urethra while exposing the tissue) so as to cause coagulation necrosis of selected portions of the compressed tissue so that as the tissue heals, the necrosed tissue slowly sloughs off during normal urination through the urinary tract so as to effectively remove the constricted portions of the prostatic urethra. Ultrasonic transducers are used from within the prostatic urethra to image the tissue as it is irradiated so as to monitor the procedure to insure proper exposure to the laser beam.

Abstract: Monocrystalline ceramic fibers are disclosed together with a process for preparing such fibers. Polycrystalline ceramic fibers in a tow are coated with a coating that is chemically substantially non-reactive with the ceramic (e.g. alumina fibers coated with molybdenum), and the coated fibers are drawn through a heating zone maintained at a temperature high enough to melt the fibers without melting the coating. The coated fibers are withdrawn from the heating zone and cooled rapidly enough to form a substantially monocrystalline ceramic. The protective coating may thereafter be removed to leave a tow of substantially single-crystal ceramic fibers. Monocrystalline ceramic fibers about 8-20 microns in diameter are prepared by the disclosed process.

Abstract: An apparatus is disclosed for producing granules or pastils from a flowable material of varying viscosity wherein material is supplied to a pressing nip between a rotating hollow roll (1) having internal teeth and an externally toothed ejection roll (2) in engagement with said hollow roll. Provided in the hollow roll (1) are bores (5) which extend from the respective teeth bottoms of the internal toothing to the outer side of the hollow roll (1) and through which the material is expelled on engagement of the ejection roll (2) and deposited in the form of pastils or granules on a cooling surface (13). On the outer periphery of the hollow roll (1) a jacket tube (3) may be positioned the jacket tube having bores which align with the bores (5) of the hollow roll (1), the jacket bores also having a reduced cross-section compared with the bores of the hollow roll to permit adaption of the apparatus to the viscosity of the flowable material to be processed.

Abstract: Method and apparatus are disclosed for a data communications system in which data packets are transmitted between two data terminal units wherein idle packets are transmitted whenever there is no data packet to send and such idle packets are utilized for detecting transmission errors in order to optimize data transmission efficiency by continually increasing, decreasing or leaving unchanged the size of data packets as a function of transmission errors.

Abstract: A bridge/router for use in bridging and routing data among one or more local area networks and a wide area network is disclosed. The bridge/router utilizes a data compressor adapted to compress data in frames adding an end of compression marker after each frame. The bridge/router provides data transmission speeds as fast as 2.048 Mbps and includes means for inhibiting the end of compression marker, while generating a data structure with each frame which is compressed with the frame of data. The data structure includes information representing the number of bytes of raw data in the corresponding frame so that on decompression the decompresser knows the number of bytes to provide in the resulting frame of decompressed data, thus avoiding the need for the end of compression marker. By inhibiting the marker compression is performed with greater efficiency.

Abstract: A gas sampling apparatus including a flexible, substantially gas-impervious, closed bag and a valve assembly mounted in a wall of the bag for providing control of gas flow between the interior and exterior of the bag. The valve assembly includes a valve body mounted in the bag wall for providing a first gas conduit to and from said interior of the bag, and a valve stem for providing a second gas conduit, the stem terminating at one end in a ball mounted on the valve body. The stem is movable about the ball between an opened position in which the gas conduits are in communication with one another and the bag may be filled or emptied through the coupled conduits, and a closed position in which the ball seals the first conduit. A valve cap is provided for capturing the stem at variable pressures between the valve body and the cap. The cap has a slot in one side in which the stem is movable tranversely to its long axis between its opened and closed positions.

Abstract: An improved fluxgate instrument for measuring heading as well and pitch and roll angles is disclosed. A plurality of fluxgate sensors are continuously energized with a DC feedback signal derived from the reading of each sensor so as to minimize magnetic cross-coupling between the sensors. In addition while two sensors are gimbally mounted to sense the horizontal components of the earth's magnetic field, the vertical field is sensed by two sensors strapped down relative to the instrument casing for sensing the earth's vertical magnetic field in order to compensate for latitude. Finally, sine and cosine coils surround the gimbally mounted sensors and generate AC fields which are sensed by the gimbally mounted sensors and are used to calculate the pitch and roll angles.

Abstract: A device for applying a thin layer of joint compound to the inner and outer surfaces of a corner bead. The device includes a hopper for supporting a quantity of joint compound. The hopper has two openings which are aligned with one another and have a cross-sectional configuration corresponding to that of a corner bead. The device includes rubber panels for closing off a selected portion of the openings. In use, a corner bead is inserted through one of the openings, pushed through the hopper where joint compound adheres to the bead, and is extracted from the other opening. The rubber panels scrape off all but a thin layer of joint compound from the concave surface of the bead and forces the bead against the bottom of the hopper so as to permit only a thin layer of joint compound to remain on the convex surface of the bead.

Abstract: A water heater (10) has a pressure-transfer module (20) interposed between an external pressurized-water circuit and the water inside the water-heater vessel (12) so that the water is at atmospheric pressure and can thus have a free upper surface. A shut-off valve in the inlet (14) to the pressure-transfer module (20) is controlled in accordance with the water level as detected by a float (74). If the water level falls below a predetermined minimum or exceeds a predetermined maximum, the shut-off valve closes so as to prevent further flow into the water heater (10) from the upstream side of the exterior circuit.

Abstract: An apparatus, preferably in the form of a resolver to digital converter for converting the amplitude modulated, encoded signals into digital signals representative of the velocity and position is described. The apparatus is of the type that includes an electronic control transformer circuit for providing respective products of sine and cosine analog signals respectively times the cosine and sine of the digital position signals and for differencing the products so as to produce an analog AC error signal. The improvement comprises means for converting the analog AC error signal into a digital DC error signal and a digital accumulator for time integrating the DC error signal to generate the digital position signal. In a preferred embodiment the output of the accumulator is digitally modulated so as to provide the digital position signal as a bit-reduced feedback signal to the electronic control transformer.

Abstract: This invention involves a system for minimizing the formation of glue drops on picks used to separate a sheet from the surface of a glue applicator drum from which a coating of adhesive is applied to the sheet. Spreader means are provided to wipe from the upstream surface of the drum at least a major portion of the adhesive that lies in the path of each pick.

Abstract: Method of chromatographically separating a mixture by contacting said mixture under chromatographic separation conditions with a chromatographic separation stationary phase comprising an N-acyl diazepine polymer. In a preferred form, the polymer has been rendered substantially alkali-stable by substitution for the hydrogen at the C3 position on the diazepine ring.

Abstract: Method of chromatographically separating a mixture by contacting said mixture under chromatographic separation conditions with a chromatographic separation stationary phase comprising an N-acyl diazepine polymer. In a preferred from, the polymer has been rendered substantially alkali-stable by substitution for the hydrogen at the C3 position on the diazepine ring.

Abstract: An assay apparatus employing total internal reflection of excitation radiation at the interface between a replaceable optically conductive assay device and a surrounding liquid phase containing the substance being assayed. The assay device is formed of a radiation transmissive, elongated fiber having on the surface thereof a component of a complex formed in an immunological-type specific reaction. A fluorophore that can be excited into fluorescence by the excitation radiation is attached to another component of the complex. The assay device also includes a boss formed of a similarly radiation transmissive material with an index of refraction preferably matched to that of the fiber, one end of the fiber being fixedly coupled to the boss. The boss is dimensioned so that the maximum solid acceptance angle for excitation radiation introduced into the fiber end lies totally within the transmissive medium of said boss.

Abstract: A constant temperature gradient fluid mass flow transducer is described. The upstream and downstream ends of a measuring section of a capillary tube of the transducer are held at respective constant temperatures by separate temperature regulated heat sinks, the downstream end being hotter. A heat conducting outer tube surrounds the measuring section and joins the heat sinks to cause the measuring section temperature to assume a substantially linear profile at a constant gradient. An electrical heater supplies heat uniformly to the measuring section to replace that transferred to the flowing fluid within the capillary tube and thereby keep the temperature and gradient constant. The voltage across the heater, proportional to the square root of mass flow rate, is taken as the output signal.

Abstract: A drain insert having an insert pipe of smaller diameter than the standing drainpipe into which the insert fits, and an elastomeric, tubular sleeve surrounding and seal-bonded to the outside of one end of the insert pipe so that a portion of the sleeve extends axially beyond that end of the insert pipe. A rigid, conical frustum is provided, the smaller end of which frustum is of lesser diameter than the internal diameter of the sleeve, the larger end of which has a diameter greater than the internal diameter of the sleeve but less than the internal diameter of the drainpipe. Coupled to the frustum and extending axially therefrom are a pair of elongated rods adapted to be inserted axially along the insert pipe. The rods are long enough so that when the frustum is adjacent the sleeve, the other ends of the rods, which are threaded, extend outside of the inlet end of the insert pipe and through holes in a bridge to tabs extending across the pipe inlet end.

Abstract: An apparatus and method for learning and filtering destination and source addresses in a local area network (LAN) system is provided to facilitate the transfer of information packets from one local area network to another. The apparatus provides a link between two (or more) remotely located LANS through the use of a LAN bridge. The apparatus has a LAN controller interface, a microprocessor, a state machine and one or more content addressable memories which function to monitor an information packet received from the LAN. One such apparatus is connected to each of the LANs to be interfaced and each of these apparatus to each other in order to communicate messages between the LANs. Upon detection of an information packet, the apparatus examines both the source and destination addresses of the packet. The source address is compared to a dynamically generated table of source addresses and then compared to the incoming destination address.