Abstract: A needleless syringe having a membrane (28) which is ruptured by gas pressure to generate a supersonic gas flow in which particles containing a therapeutic agent are injected.

Abstract: A needleless syringe having a membrane (28) which is ruptured by gas pressure to generate a supersonic gas flow in which particles containing a therapeutic agent are injected.

Abstract: A needleless syringe having a membrane which is ruptured by gas pressure to generate a supersonic gas flow in which particles containing a therapeutic agent are injected. This provides effective transdermal delivery of the therapeutic agent.

Abstract: A needleless syringe having a membrane (28) which is ruptured by gas pressure to generate a supersonic gas flow in which particles containing a therapeutic agent are injected.

Abstract: A needleless syringe having a membrane which is ruptured by gas pressure to generate a supersonic gas flow in which particles containing a therapeutic agent are injected.

Abstract: A needleless syringe having a membrane which is ruptured by gas pressure to generate a supersonic gas flow in which particles containing a therapeutic agent are injected. This provides effective transdermal delivery of the therapeutic agent.

Abstract: A filter comprising a tubular filter membrane (1) within which is mounted a concentric core (2) formed with a helical groove (3) and leaving a gap (G). Fluid to be filtered is passed in the upwards direction into the space between the core (2) and the membrane (1) and thus constrained to move in a helical path within a helical space (8) defined between the groove (3) and membrane (1), with leakage flow (7) through the gap (G) between adjacent turns of the helix. The leakage flow (7) shapes and enhances an already-existing vortex flow within the space (8) and ensures effective scouring of the membrane to prevent build-up of solids on the membrane surface. A version incorporating an externally threaded helical groove is also described. The filter is useful for a wide range of filtration purposes, particularly in ultrafiltration and microfiltration.

Abstract: Standing vortices are formed in a liquid flowing with a reversing but mean flow through a conduit, divided into a series of chambers with narrow inlet and outlets by appropriate selection of the chamber aspect ratio, Reynolds number and Strouhal number.

Abstract: A transfer membrane assembly in which one fluid is passed with a pulsatile flow through a first conduit between two transfer membranes which are provided with a close packed array of dimples so that vortex mixing occurs. Second conduits are formed on the other side of each membrane between that membrane and an adjacent profiled plate. Each dimple partially nests in a depression in the respective plate, the depressions being connected in rows by grooves. The maximum diameter and depth of each dimple is less than the corresponding dimensions of the respective depression.

Abstract: An optical sensor comprises a probe (10) and an annular optical element (13) coupled optically to a pair of optical fibres (18). Light transmitted down one fibre is reflected around the element (13) and back up the other fibre to a photodetector. The level of light received by the photodetector is dependent upon the amount of light lost from the element (13) as a result of characteristics of the surrounding medium. The presence or absence of a surrounding liquid medium may thus be sensed and a motor (34) operated to suck liquid up through the probe, when the liquid is present.

Abstract: The application relates to a method and apparatus for testing the concentration of a selected atomic scale species in a thick liquid, such as blood. The blood flows through a chamber that is in part defined by a microporous dialysis membrane permeable to atomic scale species. A measuring cell including a second chamber filled with a clean liquid is defined by the other plane of the membrane. The measuring cell incorporates a sensor having an electrode coated with a material permeable only to a selected ionic species.

Abstract: The viability of a pack of stored blood platelets is monitored by gripping the pack between two plates (6) and (7) which are closed to pinch together the walls of the bag (10) along an L-shaped seal (14), leaving a channel (17), squeezing a part (15) of the bag by means of a reciprocating plunger (19), so that the platelets continually flow to and fro between the part (15) and the part (16), through the channel (17), and passing a beam of light from an LED (27) through the channel (17), to a photoresistor (29). The AC signal from the photoresistor corresponds to the fluctuations in the intensity of the light passing through the channel (17) and the amplitude of this signal is representative of the viability, and hence the clinical acceptability, of the platelets.

Abstract: A blood monitoring system for the contents of blood bag B utilizes rigid optically clear tablet (16) bonded to rough outer surfaces of the walls of the bag to provide windows through the bag. The bag is gripped by a pair of tongs T the jaws of which have openings to receive the tablets. The outer surfaces of the jaws have ribs (33) and buttons (36) to locate the tongs, and hence the bag, accurately in position in a monitoring device, with the windows (16) in alignment with an optical system of the device.

Abstract: The viability of a pack of stored blood platelets is monitored by gripping the pack between two plates (6) and (7) which are closed to pinch together the walls of the bag (10) along an L-shaped seal (14), leaving a channel (17), squeezing a part (15) of the bag by means of a reciprocating plunger (19), so that the platelets continually flow to and fro between the part (15) and the part (16), through the channel (17), and passing a beam of light from an LED (27) through the channel (17), to a photoresistor (29). The AC signal from the photoresistor corresponds to the fluctuations in the intensity of the light passing through the channel (17) and the amplitude of this signal is representative of the viability, and hence the clinical acceptability, of the platelets.

Abstract: A blood monitoring system for the contents of blood bag B utilizes rigid optically clear tablet (16) bonded to rough outer surfaces of the walls of the bag to provide windows through the bag. The bag is gripped by a pair of tongs T the jaws of which have openings to receive the tablets. The outer surfaces of the jaws have ribs (33) and buttons (36) to locate the tongs, and hence the bag, accurately in position in a monitoring device, with the windows (16) in alignment with an optical system of the device.

Abstract: The viability of a pack of stored blood platelets is monitored by gripping the pack between two plates (6) and (7) which are closed to pinch together the walls of the bag (10) along an L-shaped seal (14), leaving a channel (17), squeezing a part (15) of the bag by means of a reciprocating plunger (19), so that the platelets continually flow to and fro between the part (15) and the part (16), through the channel (17), and passing a beam of light from an LED (27) through the channel (17), to a photoresistor (29). The AC signal from the photoresistor corresponds to the fluctuations in the intensity of the light passing through the channel (17) and the amplitude of this signal is representative of the viability, and hence the clinical acceptability, of the platelets.

Abstract: A membrane assembly, for use in mass or heat transfer or filter apparatus, comprises a pair of generally parallel plates (7) spaced apart with a profiled surface of one plate facing a similarly profiled surface of the other plate. A pair of sheets of transfer membrane material (6) are positioned closely spaced face to face between the plates with each sheet supported by and partially nesting in the profiled surface of the adjacent plate. The two membrane sheets thus provide a conduit (5) for one fluid. Between each sheet and the adjacent plate is formed a conduit for the second fluid. In use each sheet presents in its surface facing the other sheet a regular array of close packed depressions (14) which partically nest in corresponding depressions (9) in the respective plates (7).

Abstract: Transfer membrane apparatus incorporates a number of parallel channels, each channel comprising a first conduit (5) for a first fluid formed between two closely spaced transfer membranes (6). The outer face of each membrane is supported against a profiled plate (7) such that second conduits for a second fluid are provided one on each side of the first conduit (5) between a respective membrane (6) and supporting plate (7). The supporting plates (7) are mounted spaced apart in a stack with the double membranes between each adjacent pair of plates. The transfer membranes (6) are provided as parts of a continuous web (6) of transfer membrane material which is folded in concertina fashion. One set of folds (11) each extends around the front edge of a respective plate (7) and the other set of folds (12) each closes a respective first conduit (5) adjacent to the rear of the stack.

Abstract: Apparatus for effecting transfer of heat or mass between two fluids through a transfer membrane comprises a conduit for flow of one of the fluids at least partly defined by the membrane. A wall of the conduit is provided with furrows preferably extending obliquely to the general direction of fluid flow through the conduit. Means, preferably comprising a unidirectional pump for providing mean flow and a pulsatile pump for superimposing reciprocatory pulsations on the mean flow, are provided for passing fluid through the conduit in pulsatile flow, so that eddies of the fluid are formed in the hollows provided by the furrows. When the conduit is defined between two predominantly planar surfaces, these surfaces may be separated, along the ridges between the furrows, by discontinuous webs, the openings in which provide communication between adjacent furrows. These features promote mixing of the fluid and its contact with the transfer membrane.

Abstract: A method of distributing particles in a flow of gas and a needleless syringe for use in the needleless injection of particles into the skin or mucosa of a vertebrate subject are disclosed. The syringe includes a convergence which reduces pressure of the gas flowing in the gas flow path due to the Venturi effect such that particles initially located outside of the gas flow path are drawn into the gas flow path under the action of the reduced pressure and become entrained in the gas. An exit nozzle accelerates the particles so entrained. In another aspect of the invention, there is provided a method of creating a gas flow in a needleless syringe which comprises flowing gas through a first convergence into a chamber to form a transsonic gas jet in the chamber and passing the gas jet from the chamber into a second convergence and along the nozzle.