Are we teaching our students what they need to know about ageing? Results from the National Survey of Undergraduate Teaching in Ageing and Geriatric Medicine

Introduction - Learning about ageing and the appropriate management of older patients is important for all doctors. This survey set out to evaluate what medical undergraduates in the UK are taught about ageing and geriatric medicine and how this teaching is delivered. Methods – An electronic questionnaire was developed and sent to the 28/31 UK medical schools which agreed to participate. Results – Full responses were received from 17 schools. 8/21 learning objectives were recorded as taught, and none were examined, across every school surveyed. Elder abuse and terminology and classification of health were taught in only 8/17 and 2/17 schools respectively. Pressure ulcers were taught about in 14/17 schools but taught formally in only 7 of these and examined in only 9. With regard to bio- and socio- gerontology, only 9/17 schools reported teaching in social ageing, 7/17 in cellular ageing and 9/17 in the physiology of ageing. Discussion – Even allowing for the suboptimal response rate, this study presents significant cause for concern with UK undergraduate education related to ageing. The failure to teach comprehensively on elder abuse and pressure sores, in particular, may be significantly to the detriment of older patients

Enhancing chemical sensitivity of a tilted planar Bragg grating using a thin gold layer

The use of weakly tilted Bragg gratings to couple light from core waveguide modes to plasmon resonances within thin gold layers has gained increased interest over recent years. Chemical sensing using such techniques has a multitude of advantages, including access to developed gold based chemistry for surface functionalisation and an enhancement of chemical sensitivity, particularly for the biochemically ubiquitous solvent, water (1.33). Despite the obvious benefits of such devices, fabrication has principally been limited to optical fibre platforms, with little fabrication development being made in the planar regime. This work reports the use of a thin (50 nm) sputtered gold layer to enhance the chemical sensitivity of a weakly tilted planar Bragg grating (TPBG), illustrated in Figure 1 (a). Therefore, allowing access to the benefits of planar integration for this newly emerging technology

Planar waveguide water state sensor allowing detection of supercooling

A sensor believed to be the first truly integrated optical sensor demonstrating the detection of the liquid-solid phase transition of water is presented. The condensation, freezing, melting and evaporation of water are all detected with a planar silica Bragg grating operating in the 1.5 micron telecommunications window. Additionally, use of the sensor allows recognition of supercooled liquid at temperatures below the melting point of water. The device is fabricated by direct UV writing with simultaneous definition of the grating, a method inherently suited to integration with other technologies. The Bragg grating is exposed and water is allowed to condense over it. Interaction with the evanescent field causes small changes in effective index (5x10-6) which can be detected, a sufficient sensitivity to identify the phase transitions of water clearly

Development and applications of UV written waveguides

This thesis presents a description of the development of structures suitable for the technique of Direct UV Writing and demonstrates applications for which the resultant waveguiding devices may be used. The later stages of the thesis present several applications of the direct UV writing process and of devices fabricated by the technique. Firstly, direct grating writing is used as a waveguide analysis technique to measure the effects of thermal annealing on UV written structures in PECVD and FHD fabricated samples. Following this, the use of UV written devices as refractive index sensors is shown using the detection of phase transitions in water and a liquid crystal as examples. The detection of supercooling in water is demonstrated and identification of the supercool state is found to be straightforward. Building on these results, the first tunable planar Bragg grating using a liquid crystal layer is fabricated and experimentally demonstrated. An electrically controlled tuning range of 35GHz is recorded

Direct writing of waveguides is a versatile approach to sensor technology

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Planar waveguide hygrometer and state sensor demonstrating supercooled water recognition

A sensor believed to be the first truly integrated optical sensor capable of detecting the liquid-solid phase transition of water is presented. The condensation, freezing, melting and evaporation of water are all detected with a planar silica Bragg grating operating in the 1.5 µm telecommunications window. Additionally, use of the sensor allows recognition of supercooled liquid at temperatures below the melting point of water. The device, well suited for integrated optics, is fabricated by direct UV writing with simultaneous definition of the grating. The Bragg grating is exposed and water is allowed to condense over it. Interaction with the evanescent field causes small changes in effective index (5 x 10-6) which can be detected, a sufficient sensitivity to identify the phase transitions of water clearly

Direct UV writing for channel definition on FHD silica-on-silicon

Direct UV Writing (DUW) is a relatively new technique used to define channels on photosensitive planar substrates and relies on a photosensitive reaction of the substrate material to UV light irradiation. Photosensitivity refers to the permanent (but reversible) change in the index of refraction of the waveguide core when exposed to light with characteristic wavelength and intensity that depends on the core material. A laser with an emission around the 240nm absorption window is focussed down to a circular spot about 4µm in diameter and the sample is then translated relative to this writing spot, with the path of translation defining the channel waveguide structure. The more advanced Direct Grating Writing (DGW) technique involves utilising interference pattern generated by crossed UV beams and allows the simultaneous definition of channel waveguides and grating structures. The UV interference pattern is generated by intersecting two tightly focussed coherent UV beams at a fixed point in space. A photosensitive sample is then aligned with this interference spot and translated relative to it. Both of the techniques require no clean room facility and involve no etching processes. UV writing is particularly attractive for researching crossed waveguides as it is does not require etching and allows a smooth and continuous merging and splitting of channels. Characterisation of direct UV written straight channels, s-bends and crossed waveguides are presented in this manuscript. The structures were defined on 3-layer photosensitive silica-on-silicon (SiO2:Si) samples fabricated via flame hydrolysis deposition (FHD), involving the production of silica soot through the injection of halide reagents into a hydrogen/oxygen (H2/O2) flame. Straight channels written at various fluences show a saturation effect, possibly due to the sample reaching its upper limit of photosensitivity level whereas the s-bends display the reduction in excess loss with increase of bend radius as expected

Single-step fabrication of raised index X-couplers via direct UV writing

X-couplers having low polarization and wavelength dependency with 1.9-95% coupling ratios were fabricated in a single step via direct UV writing, exhibiting typical excess loss of 1.0dB. First experimental validation of analytical and BPM modeling is also presented

Tunable liquid crystal waveguide devices for filter and sensor applications

We report on the experimental demonstration of electrically tunable Bragg grating using liquid crystals. Such concept and device have been modelled in the past, but not realised experimentally. Using Direct UV writing technique, a waveguide and Bragg grating are simultaneously patterned in a planar silica on silicon substrate. Overcladding in the vicinity of the grating can be replaced by liquid crystals to exploit their electro-optic properties. The interactions of the evanescent field with the variable refractive index of the liquid crystal allow the tuning of the centre wavelength of the filter. In this way a 35 GHz tunable planar Bragg grating using liquid crystal and electric field was demonstrated

35 GHz tunable planar Bragg grating using nematic liquid crystal overlay

Tunability of a planar waveguide Bragg filter is achieved using a nematic liquid crystal overclad. Electrically induced changes in the liquid crystal refractive index allow a Bragg wavelength tuning range of 35 GHz