Abstract: A cell based assay assembly includes a biochip assembly, a liquid delivery unit and detection and recording equipment is used for conducting an assay on a biological cell as it is delivered through the biochip assembly. The biochip assembly includes a plurality of separate biochips each comprising a microchannel with input and output ports, separate reservoir wells are provided on the biochip assembly and are periodically connected to the liquid delivery unit by removable separate disclosed transfer conduits. The input and output ports of the biochip are also periodically connected to the delivery unit by the conduit. The liquid delivery unit includes a liquid link assembly and a positive displacement pump such as a syringe pump. The liquid link assembly includes pressure compressible means which acts to smooth out pressure rises by initially contacting and then expanding to in turn dispense a steady liquid delivery output below 10? per minute.

Abstract: There is provided a method of cleaning a dispensing assembly for small liquid droplets less than 50 ?l and even as low as 10 nl. A purging step with pressurised gas followed by a cleaning step using a suitable cleaning liquid is carried out a number of times.

Abstract: Biological assays using various constructions of biochips are disclosed to mirror in vivo situations. The biochip 50 comprises a microchannel 51 having a liquid outlet port 1, bubble release port 2 and a liquid outlet port 3 with an associated bubble release port 4. A multiplicity of tests can be performed often by coating the bore of the microchannel 50 which various adhesion mediating proteins or the use of chemoattractants. The assay assembly 60 comprises a syringe pump feeding the biochip 50. An inverted microscope 65, digital camera 66 and recorder 67 are provided. A sample liquid containing cells in suspension is injected slowly through the biochip and the effect of the assay recorded over a long period.

Abstract: A magnetoresistive medium (1) comprises a substrate (2) which has been treated to provide a miscut vicinal surface (3) in the form of terraces (4(a), 4(b)) and steps (5) of atomic and nanometer scale. A further upper film (11) provides upper nanowires (10(a), 10(b)). A thin protective layer (15) covers the upper nanowires (10(a), 10(b)) which form two separate subsets of upper nanowires with different exchange interaction with the substrate and thus a different response to an external magnetic field. The substrate (2) is so chosen that the width of the terraces 4(a) and 4(b) are significantly non-uniform. This leads to a different response depending on which terrace (4(a) or 4(b)) the upper film 11 overlies. It can utilise, for example, step-induced magnetic anisotropy between the upper nanowires (10(a), 10(b)) and the substrate (2).

Abstract: The invention relates to a method and apparatus for the inspection of high frequency and microwave circuits such as printed test circuit boards. The invention uses a probe or antenna (3) which is separated from the device under test (DUT) (2). The invention provides a relatively long central protruding conductor (8) for the antenna (3) which protrudes from its shielding (7). In the method, the antenna (3) is used to acquire microwave electromagnetic field measurements in a near field region of a test pont of the DUT (2). Generally, this is done at two test positions with a difference in separation (?l) between the apex (8) of the antenna (3) and the DUT (2). The two test results calculated and recorded and the difference of the microwave properties of the two tests is obtained to provide information about the operation of the DUT (2). The antenna (3) can be either a straight electric field antenna or loop antenna.

Abstract: A magnetoresistive medium (1) comprises a substrate (2) which has been treated to provide a miscut vicinal surface (3) in the form of terraces (4) and steps (5) of atomic and nanometer scale. There are discrete separated spacer nanowires (7) provided by an intermediate partial spacer film on each terrace (4) against each step (5). A further main film (11) provides main nanowires (10(a), 10(b)). A thin protective layer (15) covers the main nanowires (10(a), 10(b)) which form two separate subsets of main nanowires with different exchange interaction with the substrate and thus a different response to an external magnetic field. In use, when an external magnetic field (H) is applied the response of the main nanowires (10(a), 10(b)) changes as the exchange coupling with the substrate (2) varies and the magnetisation on the main nanowires (10(a), 10(b)) change. This is shown by the arrows while prior to the application of the external magnetic field, they might, for example, be aligned.

Abstract: There is provided a liquid droplet monitoring and measuring apparatus (1) for a liquid droplet dispensing system having a nozzle (5) with a dispensing tip (7). The apparatus (1) comprises an inner chamber (2) surrounded by an outer shield (3), preferably not in contact with each other. An RF oscillator electrically energises the liquid through an electrode (11). The inner chamber (2) is connected through pre-amplifiers (16), band pass filters (17), rectifier (18), low pass filter (19) and signal conditioning amplifier (20) to a signal read-out device (21). The operation of the apparatus is based on the measurement of the capacitance between the nozzle (5) and the inner chamber (2). As a droplet (15) grows on the dispensing tip (7), the capacitance between the nozzle (5) and the inner chamber (2) increases. Therefore, the signal detected and received by the signal read-out device (21) changes. This change is directly related to the volume of the droplet which can therefore be measured.

Abstract: A liquid outlet link assembly is provided for liquid delivery output rates below 10 &mgr;l per minute so as to smooth out the flow from a positive displacement pump which has an immediate step pumping rate which is relatively substantially larger than the delivery rate required through the liquid outlet means. Essentially, this liquid link assembly has a bubble of air or some other pressure activated expansion means which initially contracts on the step pump such as a syringe pump operation and then gradually expands over time, allowing a steady output rate through the link assembly.

Abstract: Biological assays using various constructions of biochips are disclosed to mirror in vivo situations. The biochip 50 comprises a microchannel 51 having a liquid outlet port 1, bubble release port 2 and a liquid outlet port 3 with an associated bubble release port 4. A multiplicity of tests can be performed often by coating the bore of the microchannel 50 which various adhesion mediating proteins or the use of chemoattractants. The assay assembly 60 comprises a syringe pump feeding the biochip 50. An inverted microscope 65, digital camera 66 and recorder 67 are provided. A sample liquid containing cells in suspension is injected slowly through the biochip and the effect of the assay recorded over a long period.

Abstract: Biological assays using various constructions of biochips are disclosed to mirror in vivo situations. The biochip 50 comprises a microchannel 51 having a liquid outlet port 1, bubble release port 2 and a liquid outlet port 3 with an associated bubble release port 4. A multiplicity of tests can be performed often by coating the bore of the microchannel 50 which various adhesion mediating proteins or the use of chemoattractants. The assay assembly 60 comprises a syringe pump feeding the biochip 50. An inverted microscope 65, digital camera 66 and recorder 67 are provided. A sample liquid containing cells in suspension is injected slowly through the biochip and the effect of the assay recorded over a long period.

Abstract: A dispensing assembly for liquid droplets that includes a dispenser connected to a liquid carrying pipe which in turn is connected to a source of pressurized liquid. The dispenser has an elongated body member having a main bore connected to the liquid carrying pipe. At the other end, the main bore has a valve seat that is connected to a nozzle having a nozzle bore terminating in a dispensing tip. An elongated valve boss of ferromagnetic material covered with a soft polymer is mounted in the main bore and has a cross-sectional area less than that of the main bore. A separate valve boss actuating coil assembly has upper and lower coils that are separate from the main body that can be unplugged from both coils and from the liquid carrying pipe. As such, the main body can be a disposable member.

Abstract: A dispensing assembly for liquid droplets that includes a dispenser connected to a liquid carrying pipe which in turn is connected to a source of pressurized liquid. The dispenser has an elongated body member having a main bore connected to the liquid carrying pipe. At the other end, the main bore has a valve seat that is connected to a nozzle having a nozzle bore terminating in a dispensing tip. A valve boss of ferromagnetic material covered with a soft polymer is mounted in the main bore and has a cross-sectional area less than that of the main bore. A separate valve boss actuating coil assembly has upper and lower coils that are separate from the main body that can be unplugged from both coils and from the liquid carrying pipe. As such, the main body can be a disposable member.

Abstract: A dispenser (1) for liquid droplets of the order of 30 &mgr;l or less in volume. The dispenser (1) comprises a metering valve body (2) having a main bore (3) connected by a pipe (4) to a pressurised liquid delivery source (not shown). The body (2) comprises a base (5) from which is mounted a nozzle (6) projecting above the base (5) to form a valve seat (7). An actuating coil assembly (11) is mounted on the exterior of the body (2) for moving a floating valve boss (15) of a ferromagnetic material. Sensing coils (20, 21) are mounted around and spaced-apart along the body (2) forming part of a valve boss detector. The valve boss detector acts as a positional movement detector so that the opening and closing of the valve can be accurately controlled and bouncing of the valve boss (15) either against an end stop (9) or on the valve seat (7) can be greatly minimized, if not prevented fully, by careful operation of the actuating coil assembly (11).

Abstract: A multi nozzle dispensing head for a dispensing assembly for liquid droplets of 10 &mgr;l or less. The dispensing assembly comprises a pressurised liquid delivery source feeding a dispenser including a metering valve and the multi nozzle dispensing head. The multi nozzle dispensing head comprises a bored primary nozzle feeding a manifold forming a split channel which in turn feeds bored secondary nozzles. The aggregate resistance to flow in all the secondary nozzle bores is greater than the resistance to flow in the split channel, generally by a factor of 10.

Abstract: A liquid outlet link assembly is provided for liquid delivery output rates below 10 &mgr;l per minute so as to smooth out the flow from a positive displacement pump which has an immediate step pumping rate which is relatively substantially larger than the delivery rate required through the liquid outlet means. Essentially, this liquid link assembly has a bubble of air or some other pressure activated expansion means which initially contracts on the step pump such as a syringe pump operation and then gradually expands over time, allowing a steady output rate through the link assembly.

Abstract: A dispenser (1) for liquid droplets of the order of 30 &mgr;l or less in volume. The dispenser (1) comprises a metering valve body (2) having a main bore (3) connected by a pipe (4) to a pressurised liquid delivery source (not shown). The body (2) comprises a base (5) from which is mounted a nozzle (6) projecting above the base (5) to form a valve seat (7). An actuating coil assembly (11) is mounted on the exterior of the body (2) for moving a floating valve boss (15) of a ferromagnetic material. Sensing coils (20, 21) are mounted around and spaced-apart along the body (2) forming part of a valve boss detector. The valve boss detector acts as a positional movement detector so that the opening and closing of the valve can be accurately controlled and bouncing of the valve boss (15) either against an end stop (9) or on the valve seat (7) can be greatly minimized, if not prevented fully, by careful operation of the actuating coil assembly (11).

Abstract: A conventional syringe pump (10) is used to dispense liquids of less than 5 &mgr;l in volume in a dispensing assembly (1). There is a divider barrier formed by a flexible elastomer membrane (5) clamped between an inner part (3) and an outer part (4) of a dispenser (2). The dispenser (2) has a bore divided into a system liquid reservoir (6) and a sample liquid reservoir (7). The system liquid reservoir (6) connects to the pump (10) and the sample liquid reservoir (7) communicates with a nozzle (15) having a dispensing tip (16). The membrane (5) is virtually incompressible and therefore the pump (10) can dispense accurately. Electrostatic drop detachment using an electrode (25) electrically coupled to the dispensing tip (16) and a conducting plate (19) forming a receiving electrode below a substrate (20).

Abstract: Biological assays using various constructions of biochips are disclosed to mirror in vivo situations. The biochip 50 comprises a microchannel 51 having a liquid outlet port 1, bubble release port 2 and a liquid outlet port 3 with an associated bubble release port 4. A multiplicity of tests can be performed often by coating the bore of the microchannel 50 which various adhesion mediating proteins or the use of chemoattractants. The assay assembly 60 comprises a syringe pump feeding the biochip 50. An inverted microscope 65, digital camera 66 and recorder 67 are provided. A sample liquid containing cells in suspension is injected slowly through the biochip and the effect of the assay recorded over a long period.