Public Health Laboratory Service Board

Other

Microbiological Research Authority Camr (centre for Applied Microbiology

David J Clarke

Robert J Carr

Barrie C Blake-Coleman

Barry C Blake-Coleman

David J Schiffrin

Tony Atkinson

Michael H Harrison

Martin C Wiles

Freidoun Zamani-Farahani

Barry C Blake

Sumaia Al-Shukri

Anthony Atkinson

Analytical apparatus includes a pyroelectric or other thermo-electric transducer element (10) in strip form. Thin film electrodes (12,14) are provided and one or more dots of reagent (16) are deposited on the transducer surface. A small amount of biological or other sample is deposited over the reagent dots which undergo selective colorimetric changes. The transducer is illuminated from below by LED light sources (24) and light absorption in the reagent regions is detected as microscopic heating at the transducer surface. The electrical signal output from the pyroelectric transducer is processed to derive analyte information.

Analytical apparatus utilizing a colorimetric or other optically

Examination of objects of macromolecular size

Electrochemical cell, reference electrode and electrochemical method

Particle velocity is determined optically through the use of crossed interference fringe patterns. The fringe patterns are produced by passing laser beams of distinct wavelength along a common optical fibre and through two crossed diffraction gratings which are bonded to the free end of the fibre. Each diffraction grating is constructed in the manner of an interference filter so as to produce interference fringes at one wavelength but to transmit the other wavelength substantially uniformly across the grating. Other interference elements can be used in place of diffraction gratings and the use of a single diffraction grating is envisaged in certain circumstances. An indication of the sense of particle movement can be achieved by creating a fringe pattern of steadily increasing fringe spacing.

Optical determination of velocity using crossed interference fringe

Electrochemical electrodes

Optical analysis

Method for selective filtering of a fluid using porous piezoelectric

A method of investigating the condition of biological particles, in particular the fraction of viable cells in a bacteria population involves applying a voltage and monitoring the voltage induced by magnetic induction in a detector coil. The applied voltage is of a variable frequency alternating voltage and is preferably induced in the medium through a drive coil.

Apparatus for investigating the condition of a bacteria containing

Apparatus for determining the amount of biological material in a fluid medium, typically the concentration of bacteria in a fermentation chamber, has a test cell through which a medium can be passed with bacteria or after bacteria have been removed by filtration. In the test cell a vibratory element is excited to a resonant frequency indicative of density and a comparison of medium density and medium plus bacteria density reveals the bacteria concentration.

Determining amount of biological material

Method for investigating the condition of a bacterial suspension through

Apparatus for use in measuring fluid density comprises a fluid carrying helical sample tube 50 made of a conductive material for passing current therethrough. A cylindrical coil fixing sleeve 58 form surrounds the helical sample tube and engages the tube to prevent relative movement of the turns. A high flux permanent magnet 60 is carried on one post 54 and is aligned along the axis of the tube. The magnetic field established by magnet 60 and the pole extension 64 will subject each current-carrying length element of the sample tube to an axial force, the sum of these forces resulting in a bodily axial movement of the sample tube. The sample tube is excited to spring resonance by passing current through the sample tube. The resonant frequency is measured and is indicative of the mass of the fluid contained in the coil and thereby of the fluid density.

Apparatus for measuring fluid density

Growing community of inventors

Salisbury, United Kingdom

David J Clarke