Abstract:
Surgical implants, especially endoprosthetic orthopaedic implants and sutures, are rendered antimicrobial by the presence of a bioerodible metallic silver component, especially a surface coating, which provides in vivo a sustained release of silver ions in a concentration sufficient to provide a localized antimicrobial effect but insufficient to cause significant damage to connective tissue. Latently bioerodible silver components of an implant can be activated by, for example, abrasion, heating to above about 180` or, especially, contact with hydrogen peroxide.
Abstract:
A method of sensing the optical deflection function of an approximately cylindrical object, such as an optical fibre preform, comprises illuminating the object with collimated light; focusing the transmitted light so that in the focal plane the distance of the light from the optical axis is linearly proportional to the angle through which light has been deviated by the object; optically modulating the focused light so that a property of the light varies as a function of said distance, and calculating the deflection function from the modulated light. The modulations may be spatial or temporal. The refractive index profile can also be calculated.
Abstract:
Compositions containing insect behaviour modifying compounds containing carbon-to-carbon unsaturation, e.g. pheromones, are stabilised by the addition of a tertiary phenylene diamine of formula: (FORMULA) wherein R1 represents an aromatic residue, R2 represents H or an alkyl, alkenyl, cyloalkyl, cycloalkylalkyl, alkaryl, aralkyl, aryl, acyl, acyloxy or nitroso group and R3 and R4, which may be the same or different, each represents an alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, alkaryl, aralkyl, aryl, acyl, acyloxy or nitroso group. These compositions are usefully enclosed in micro-capsules for spraying in an area of insect infestation in order to disrupt mating patterns, and the invention particularly applies to micro-encapsulation of the compositions in polyureas, the tiertiary phenylene diamines having the advantage that they do not react with the diisocyanate monomer during the micro-encapuslation process.
Abstract:
There are provided processes for carrying out enzymatic reactions, especially processes for the oxidative or reductive transformation of organic compounds catalysed by enzymes, in which the enzymes require a continuing supply of reducing equivalents to regenerate reduced enzyme species in enzymatically active form, and in which the reducing equivalents are derived electrochemically, including electrochemically from molecular hydrogen, the reducing equivalents preferably being passed directly to the enzyme from the cathode of an electrochemical system.
Abstract:
PCT No. PCT/GB78/00052 Sec. 371 Date Aug. 13, 1979 Sec. 102(e) Date Aug. 6, 1979 PCT Filed Dec. 8, 1978 PCT Pub. No. WO79/00380 PCT Pub. Date Jun. 28, 1979.A method and monitoring apparatus for use in electrical discharge machining (EDM) are described. The method and apparatus relate to the problem of distinguishing between arcing and sparking in EDM and employ sound (including ultrasonic signals) emitted from the gap between an electrode and a workpiece to generate signals which differentiate between the two conditions. In an embodiment disclosed the signals generated are used in an apparatus which indicates visually whether sparking or arcing is taking place and in other embodiments monitoring is used to control parameters of EDM machining.
Abstract:
A method and apparatus for use in EDM are described. Known EDM techniques require the voltage applied between the electrode (11) and the workpiece (10) to be removed either periodically or after a predetermined integrated current has passed and the resulting interruptions add to the time required for machining. In the present invention the voltage is applied until an arc is imminent or is detected and then the voltage is removed for a time sufficient to allow de-ionization of the gap between the electrode (11) and the workpiece (10) to occur.
Abstract:
The separation of substances by membrane electrophoresis using the principle of isoelectric focussing is improved by the use of membranes of known isoelectric point and having buffering capacity. When such membranes are arranged in series of increasing isoelectric point from the anode (+) to the cathode (-) in a pH gradient of increasing pH in the same direction, and each membrane is located between electrolyte zones having pHs respectively lower and higher than its isoelectric point, the tendency for electro-endosmosis to occur during electrophoresis is substantially reduced. Methods for chemical treatment of agarose and other gel membranes to introduce acidic and basic groups so as to confer buffering power at the isoelectric point are described. These include the attachment of ampholytes to the gel by intermediate chemical linkages. Under varying chemical conditions membranes exhibiting isoelectric properties over a range of pH values can be prepared and specific values predetermined to within narrow limits. The membranes are used in multicompartment apparatus with separate cooling of individual circulating electrolyte zones and may be in the form of sheet membranes mounted in a nesting configuration one above the next with gravity flow of electrolyte and edge sealing between the membranes. High current and large scale use of the method for preparative as well as analytical purposes are envisaged.
Abstract:
Compounds of formula (II), wherein n is 0, 1 or 2, R1, R2, R3 and R4 are each separately selected from hydrogen, unsubstituted acyclic aliphatic hydrocarbon groups having a maximum of six carbon atoms and C1-6 alkyl groups substituted by a hydroxy group or by a C1-6 alkoxy group, or one of R1 and R2 and one of R3 and R4 is hydrogen and the others together form a trimethylene, tetramethylene or pentamethylene bridging group, R5 is hydrogen or an unsubstituted acyclic aliphatic hydrocarbon group having a maximum of six carbon atoms, and R6 is an acyclic aliphatic hydrocarbon group having a maximum of six carbon atoms or a group CH2R7 in which R7 is a C1-5 alkyl group substituted by a hydroxy group or by a C1-6 alkoxy group, or a salt thereof formed with a physiologically acceptable inorganic or organic acid, are of use in therapy, particularly as cardioprotective agents.
Abstract:
A method of building a free standing or building wall using prefabricated wall panels (10, 12, 14) comprises factory assembly of a wall panel from traditional or other building bricks or blocks and providing the panel with integral support means (26) to resist separation of the bricks or blocks when lifted for transport. A joint element (118) for placement between adjacent edges of the panels provides a labyrinth seal (102) with interleaved seal elements extending lengthwise of the joint. Spring means (124) acts between opposite sides (120, 122) of the joint so that it is resiliently compressible to accommodate differing spacings between the panels. A thermal insulation compartment (126, 128) is provided within the joint element.
Abstract:
A source of atomic or molecular particles includes a source of ionised particles (1), an extraction electrode (2) and an einzel lens (3) to focus a beam of particles. A Wien filter (4) selects particles in said beam having a predetermined velocity and a charge exchange cell (7) neutralises the ionised particles prior to the extraction of non-ionised particles from the beam.