Abstract: A method is provided for the formation of liposomes of 0.1 &mgr;m to 50 &mgr;m in diameter having unilamella or multilamella structure and containing water insoluble or undissolved particulate materials comprising (a) forming liposomes and removing substantially all of any organic solvent used in their preparation, (b) freeze drying the liposomes so formed and then (c) rehydrating them in intimate admixture with the particulate material. Preferred encapsulated materials are particulate materials, most preferably microorganisms, plant or animal cells or water insoluble structures having organic solvent labile biochemical or immunological activity, but any water insoluble particulate may be encapsulated using the method. For example catalysts or drugs that are sparingly soluble may also be so incorporated such that slow release into the a patients body may be provided while release of detergents included in the many liposome preparation protocols may be avoided.

Abstract: A large core photonic crystal fibre for transmitting radiation having a core comprising a substantially transparent core material and having a core diameter of at least 5&mgr;. The fibre also comprises a cladding region surrounding the length of core material, wherein the cladding region comprises a first substantially transparent cladding material, having a first refractive index, and wherein the first substantially transparent cladding material has embedded along its length a substantially periodic A array of holes, wherein the holes are filled with a second cladding material having a second refractive index less than the first refractive index, such that radiation input to the optical fibre is transmitted along the length of the core material in a single mode of propagation. In a preferred embodiment, the core diameter may be at least 20&mgr;, and may be as large as 50&mgr;.

Abstract: A reaction vessel for holding reagents, the vessel made of electrically conducting polymer capable of emitting heat when an electric current is passed through it. The reaction vessel includes a reagent container, such as a capillary tube, slide or chip, in close contact with the electrically conducting polymer. The polymer may be in the form of a film which is wrapped around the tube to form a sheath. This provides a readily controllable heating supply which may be heated and cooled to desired temperatures rapidly. An apparatus suitable for thermal cycling reactions, such as the polymerase chain reaction (PCR) including one or more reaction vessels as well as methods for carrying out such reactions are also described.

Abstract: A liquid crystal composition comprises a host material capable of exhibiting a smectic C phase, and a chiral dopant material which imparts or enhances chirality in the host material. The composition exhibits &tgr;-Vmin curves. The chiral dopant material comprises at least first and second chiral centers. The chiral centers individually produce, in the liquid crystal composition, different and complementary temperature coefficients of spontaneous polarization within a predetermined temperature range. The chiral centers are present in the liquid crystal composition in relative amounts such that regions of the &tgr;-Vmin curves across the predetermined temperature range are substantially coincident.

Abstract: An optical fiber bend sensor (10) measures the degree and orientation of bending present in a sensor length (30) portion of a fiber assembly (26). Within a multicored fiber (30, 32,34), cores (62, 66) are grouped in non-coplanar pairs. An arrangement of optical elements (28, 36, 38) define within each core pair (62, 66) two optical paths (122, 124) which differ along the sensor length (30): one core (62) of a pair (62, 66) is included in the first path (122), and the other core (66) in the second path (124). A general bending of the sensor region (30) will lengthen one core (62, 66) with respect to the other. Interrogation of this length differential by means of interferometry generates interferograms from which the degree of bending in the plane of the core pair is extracted. Bend orientation can be deduced from data extracted from multiple core pairs.

Abstract: An electroluminescent device (10) comprises a porous silicon region (22) adjacent a bulk silicon region (20), together with a top electrical contact (24) of transparent indium tin oxide and a bottom electrical contact (26) of aluminum. The device includes a heavily doped region (28) to provide an ohmic contact. The porous silicon region (22) is fabricated by anodizing through an ion-implanted surface layer of the bulk silicon. The silicon remains unannealed between the ion-implantation and anodization stages. The device (10) has a rectifying p-n junction within the porous silicon region (22).

Abstract: When a ferroelectric liquid crystal display (FLCD) panel is addressed in such a manner as to cause adjacent or successive pixels to display different levels of greyscale, the viewer may perceive a pseudo edge effect caused by the perceived error in the transmission level at the transition between the two grey levels. In order to decrease this perceived error, the panel is addressed such that, at the transition between the two grey levels, for example between the grey levels “3” and “4”, the most significant bit of the addressing scheme incorporates an analogue grey level, for example a half level. This results in a perception level exhibiting a lower absolute error in the relative grey level than would be obtained if no special measures were taken to compensate for the perceived error at the transition. This compensation technique is applicable to addressing schemes utilizing temporal dither (TD) as well as spatial dither (SD).

Abstract: A method of addressing a liquid crystal device having a plurality of scanning electrodes and a plurality of data electrodes defining a plurality of pixels at the intersections between at least one of the plurality of scanning electrodes and at least one of the plurality of data electrodes, the method comprising applying one frame of a scanning signal to one of the plurality of scanning electrodes, applying a data signal to at least one of the plurality of data electrodes, one frame of the scanning signal comprising n strobe portions, where n is an integer greater than 1, for co-operation with the at least one data signal to address one of the plurality of pixels, and at least one blanking portion, the number of blanking portions not exceeding (n−1).

Abstract: A liquid crystal device is addressed in a multiplexed manner by a scanning signal applied in turn to a first set of electrodes together with data signals applied to a second set of electrodes. The first and second sets of electrodes define a plurality of pixels. The pattern to be exhibited by the device determines the waveform applied to the second set of electrodes which can vary between extremes of frequency. This has adverse effects on device performance, particularly with regard to contrast. To ameliorate the problem a low frequency signal is added to the scanning signal which incorporates a known strobe pulse. This low frequency signal reduces the effect on the pixels of the extremes of data signal frequency.

Abstract: A method of determining the location of an unknown source 10 transmitting a signal to satellite relays 14 and 16 comprises receiving replicas of the signal from the relays at receivers 18. The receivers 18 also transmit and receive reference signals via respective relays 14 and 16. All signals are downconverted, digitized and correlated with one another in pairs using a correlation function including a term which compensates for time varying differential frequency offset (DFO). Compensation for time varying differential time offset or time dilation is achieved by replicating or adding to signal samples and applying phase corrections. This procedure enables a correlation maximum and associated measurement results to be obtained despite the effects of relay satellite motion which mitigate against this. Results are used in a prior art geometrical technique to locate the unknown transmitter.

Abstract: The present invention provides proteins for use in vaccines which are capable of inducing protective antibodies directed against C. perfringens epsilon toxin when administered to animals or man and thereby providing prophylaxis or therapy against infection by C. perfringens epsilon toxin. Particularly the present invention provides proteins which are based upon the mature toxin of the clostridium perfringensepsilon toxin gene, but which have a mutation such that the amino acid at position 106 is different to the wild-type sequence and their use in vaccine compositions.

Abstract: A fluorinated phenyl compound having the general formula [1]: wherein each of s, v and x=0 or 1, each of t and u=1, 2 or 3, and each of y and z=0, 1 or 2; A, B and C are independently selected from conjugated cyclic moieties including heterorings and fused rings; R1 and R3 may be independently cyano, or (C1-C12)alkyl, (C1-C12)alkoxy, (C1-C11) alkoxycarbonyl or (C1-C11)alkylcarbonyloxy which may be fluoro- and/or cyano-substituted; R2=H or F; R4=H or F; and R5=H or F. Such compounds have high transverse dipole moments and are potentially useful in liquid crystal compositions and in devices including same.

Abstract: Zirconium precursors for use in depositing thin films of or containing zirconium oxide using an MOCVD technique have the following general formula: Zrx(OR)yL, wherein R is an alkyl group; L is a &bgr;-diketonate group; x=1 or 2; y=2, 4 or 6; and z=1 or 2.

Abstract: Liposomes containing a photosensitive material, which undergoes photodegredation on exposure to U.V. light, is retained within the liposome together with a light absorbing material capable of increasing the photostability of the photosensitive. Methods of preparing pharmaceutical compositions containing these liposomes are provided.

Abstract: An electroluminescent device (10) comprises a porous silicon region (22) adjacent a bulk silicon region (20), together with a top electrical contact (24) of transparent indium tin oxide and a bottom electrical contact (26) of aluminum. The device includes a heavily doped region (28) to provide an ohmic contact. The porous silicon region (22) is fabricated by anodizing through an ion-implanted surface layer of the bulk silicon. The silicon remains unannealed between the ion-implantation and anodization stages. The device (10) has a rectifying p-n junction within the porous silicon region (22).

Abstract: Skin protection agents such as topical compositions which can prevent the passage of toxic chemicals through the skin, such as barrier creams. Formulations may contain hexamethylene tetramine or derivatives or analogues thereof, which react with alkylating agents such as sulfur mustard, and which are suitable for formulation into topical compositions. The formulations additionally may contain perfluorinated polymeric compounds which are effective barrier compounds for a range of toxic chemicals.

Abstract: An optical device (300) comprises a multilayer structure, formed by wafer bonding, incorporating in sequence a silicon dioxide layer (304), a buried silicide layer (306), a contact layer (308) and a silicon surface layer (310). The surface layer (310) is selectively etched to form an exposed rib (312). An upper surface of the rib (312) is doped to form an elongate electrode (314) therealong. The surface layer (310) is selectively etched to the contact layer (308) in regions remote from the rib (312) to form via channels (316a, 316b) for making electrical connection to the contact layer (308). The rib (312) forms a waveguide along which radiation propagates. When the electrode (314) is biased relative to the contact layer (308), charge carriers are injected into the rib (312) and induce refractive index changes in a central region (324) thereof where most of the radiation propagates along the rib (312).

Abstract: A method of making semiconductor quantum wires employs a semiconductor wafer (14) as starting material. The wafer (14) is weakly doped p type with a shallow heavily doped p layer therein for current flow uniformity purposes. The wafer (14) is anodised in 20% aqueous hydrofluoric acid to produce a layer (5) microns thick with 70% porosity and good crystallinity. The layer is subsequently etched in concentrated hydrofluoric acid, which provides a slow etch rate. The etch increases porosity to a level in the region of 80% or above. At such a level, pores overlap and isolated quantum wires are expected to form with diameters less than or equal to 3 nm. The etched layer exhibits photoluminescence emission at photon energies well above the silicon bandgap (1.1 eV) and extending into the red region (1.6-2.0 eV) of the visible spectrum.

Abstract: A method of monitoring material parameters of a sample (4) (for example electrical properties of a semiconductor) during processing (for example during manufacture) which uses ellipsometric techniques to study the changes induced in the ellipsometric spectra of the material, by modulation of the internal electric field of the material, and determining from these changes the material parameters of interest The means of modulation can be a source of electromagnetic radiation, for example a laser (8). The ellipsometer used may include an array of photodetectors. The process allows the real time monitoring of the process under examination.

Abstract: A noise reduced photon detector incorporates an array (10) of semiconductor diode detector elements (12). Each element (12) has an extrinsic active layer (20) sandwiched between two layers (18, 22) of wider bandgap and mutually opposite conductivity type. These layers are in turn sandwiched between two further layers (16, 24) of wider bandgap than the active layer (20) and of higher doping than the other layers (18, 22). A mirror (34) extends round much the array (10) and isolates each element (12) from photons emitted by other elements (12). In operation the elements (12) are reverse biased and exhibit negative luminescence which reduces their photon emission. These two effects reduce unwanted photon generation and absorption, and consequently photon noise is also reduced.