Anterior eye health recording

Aims: To survey eye care practitioners from around the world regarding their current practice for anterior eye health recording to inform guidelines on best practice. Methods: The on-line survey examined the reported use of: word descriptions, sketching, grading scales or photographs; paper or computerised record cards and whether these were guided by proforma headings; grading scale choice, signs graded, level of precision, regional grading; and how much time eye care practitioners spent on average on anterior eye health recording. Results: Eight hundred and nine eye care practitioners from across the world completed the survey. Word description (p <. 0.001), sketches (p = 0.002) and grading scales (p <. 0.001) were used more for recording the anterior eye health of contact lens patients than other patients, but photography was used similarly (p = 0.132). Of the respondents, 84.5% used a grading scale, 13.5% using two, with the original Efron (51.6%) and CCLRU/Brien-Holden-Vision-Institute (48.5%) being the most popular. The median features graded was 11 (range 1-23), frequency from 91.6% (bulbar hyperaemia) to 19.6% (endothelial blebs), with most practitioners grading to the nearest unit (47.4%) and just 14.7% to one decimal place. The average time taken to report anterior eye health was reported to be 6.8. ±. 5.7. min, with the maximum time available 14.0. ±. 11. min. Conclusions: Developed practice and research evidence allows best practice guidelines for anterior eye health recording to be recommended. It is recommended to: record which grading scale is used; always grade to one decimal place, record what you see live rather than based on how you intend to manage a condition; grade bulbar and limbal hyperaemia, limbal neovascularisation, conjunctival papillary redness and roughness (in white light to assess colouration with fluorescein instilled to aid visualisation of papillae/follicles), blepharitis, meibomian gland dysfunction and sketch staining (both corneal and conjunctival) at every visit. Record other anterior eye features only if they are remarkable, but indicate that the key tissue which have been examined.

Simplified recording of soft contact lens fit

Purpose: To determine the critical fitting characteristics of modern soft contact lens fits and from this to devise a simplified recording scheme. Methods: Ten subjects (aged 28.1 ± 7.4 years) wore eight different modern soft contact lenses. Video was captured and analysed of blink (central and up-gaze), excursion lag (up, down, right and left gaze) and push-up movement, centration and coverage. Results: Lens centration was on average close to the corneal centre. Movement on blink was significantly smaller in up-gaze than in primary-gaze (p<0.001). Lag was greatest in down-gaze and least in up-gaze (p<0.001). Push-up test recovery speed was 1.32±0.73mm/s. Overall lens movement was determined best by assessing horizontal lag, movement on blink in up-gaze and push-up recovery speed. Steeper lens base-curves did not have a significant effect on lens fit characteristics. Contact lens material did influence lens fit characteristics, particularly silicone-hydrogels which generally had lower centration and a faster push-up speed of recovery than HEMA lenses (p<0.05). Conclusion: Lag on vertical gaze, and movement on blink in primary gaze generally provide little extra information on overall lens movement compared to horizontal lag, movement on blink in up gaze and push-up recovery speed. They can therefore be excluded from a simplified recording scheme. A simplified and comprehensive soft contact lens fit recording system could consist of a cross-hairs indicating the centre of the cornea; a circle to indicate the lens centration; a mark on the relevant position of the circle to indicate any limbal incursion; a grade (‘B’) below for movement with blink in up-gaze, a grade (‘L’) to the side for horizontal lag and a grade above (‘P’) for the assessed push-up recovery speed.

An investigation of thin film magnetic recording media

Mechanical, physical and chemical changes in the surface of commercial thin film metal evaporated magnetic recording media have been correlated to recording error and signal degradation measurements. Modified and adapted commercial Hi-8 video recorders have been used for sample generation whilst analytical techniques such as SXPS,IMS and SEM have been employed in the surface characterisation. The durability of the media was assessed through stop motion (still frame) and cycling tests, where error growth and signal degradation were measured as a function of running time. The tests were performed under ambient (22°C, 40% RH) and high humidity (22°C, 80% RH) conditions. Characterisation of the lubricant layer on each tape was performed through models based on XPS and angle resolved XPS. The lubricant thickness can significantly affect the durability and signal output level of a thin film tape and thus it is important that reliable quantification can be achieved. Various models were considered for determining the lubricant thickness although ultimately, the most suitable technique was deemed to be a model that assumed a uniform layer structure. In addition to thin film metal evaporated media, equivalent durability tests and surface analysis experiments were performed using a commercial metal particle tape in order that comparisons could be made between the two types of recording media. The signal performance of the thin film metal evaporated media was found to be quite different from that for the metal particle tape since dropout errors and signal degradation increased at a much earlier stage. Extensive surface analyses enabled the mechanisms responsible for media failure and error growth to be identified in the ME and MP tapes and these were found to result from cyclic stressing and fatigue on the immediate substrate of the media.

The tribology of laminated magnetic recording heads

This thesis investigates the mechanisms that lead to pole tip recession (PTR) in laminated magnetic recording heads (also known as "sandwich heads"). These heads provide a platform for the utilisation of advanced soft magnetic thin films in practical recording heads suitable for high frequency helical scan tape recording systems. PTR results from a differential wear of the magnetic pole piece from the tape-bearing surface of the head. It results in a spacing loss of the playback or read signal of 54.6dB per recording wavelength separation of the poles from the tape. PTR depends on the material combination used in the head, on the tape type and the climate - temperature and relative humidity (r.h.). Five head materials were studied: two non-magnetic substrate materials- sintered multi granular CaTi03 and composite CaTi03/ZrTi04/Ti02 and three soft magnetic materials- amorphous CoNbZr, and nanocrystalline FeNbSiN and FeTaN. Single material dummy heads were constructed and their wear rates measured when cycling them in a Hi-8 camcorder against commercially available metal particulate (MP) and metal evaporated (ME) tapes in three different climates: 25°C/20%r.h., 25°C/80%r.h. and 40°C/80%r.h. X-ray photoelectron spectroscopy (XPS) was used to examine changes the head surface chemistry. Atomic force microscopy (AFM) was used to examine changes in head and tape surface topography. PTR versus cycling time of laminated heads of CaTi03/ZrTiO4/Ti02 and FeTaN construction was measured using AFM. The principal wear mechanism observed for all head materials was microabrasion caused by the mating body - the tape surface. The variation in wear rate with climate and tape type was due to a variation in severity in this mechanism, except for tape cycling at 40°C in which gross damage was observed to be occurring to the head surface. Two subsidiary wear mechanisms were found: third body scratching (all materials) and grain pullout (both ceramics and FeNbSiN). No chemical wear was observed, though tribochemical reactions were observed on the metal head surfaces. PTR was found to be caused by two mechanisms - the first differential microabrasion of the metal and substrate materials and which was characterised by a low (~10nm) equilibrium value. The second was by deep ploughing by third body debris particles, thought mainly to be grain pullout particles. This level of PTR caused by this mechanism was often more severe, and of a non-equilibrium nature. It was observed more for ME tape, especially at 40°C/80%r.h. and 25°c/20%r.h. Two other phenomena on the laminated head pole piece were observed and commented upon: staining and ripple texturing.

The tribology of linear tape recording systems

This thesis is devoted to the tribology at the head~to~tape interface of linear tape recording systems, OnStream ADRTM system being used as an experimental platform, Combining experimental characterisation with computer modelling, a comprehensive picture of the mechanisms involved in a tape recording system is drawn. The work is designed to isolate the mechanisms responsible for the physical spacing between head and tape with the aim of minimising spacing losses and errors and optimising signal output. Standard heads-used in ADR current products-and prototype heads- DLC and SPL coated and dummy heads built from a AI203-TiC and alternative single-phase ceramics intended to constitute the head tape-bearing surface-are tested in controlled environment for up to 500 hours (exceptionally 1000 hours), Evidences of wear on the standard head are mainly observable as a preferential wear of the TiC phase of the AI203-TiC ceramic, The TiC grains are believed to delaminate due to a fatigue wear mechanism, a hypothesis further confirmed via modelling, locating the maximum von Mises equivalent stress at a depth equivalent to the TiC recession (20 to 30 nm). Debris of TiC delaminated residues is moreover found trapped within the pole-tip recession, assumed therefore to provide three~body abrasive particles, thus increasing the pole-tip recession. Iron rich stain is found over the cycled standard head surface (preferentially over the pole-tip and to a lesser extent over the TiC grains) at any environment condition except high temperature/humidity, where mainly organic stain was apparent, Temperature (locally or globally) affects staining rate and aspect; stain transfer is generally promoted at high temperature. Humidity affects transfer rate and quantity; low humidity produces, thinner stains at higher rate. Stain generally targets preferentially head materials with high electrical conductivity, i.e. Permalloy and TiC. Stains are found to decrease the friction at the head-to-tape interface, delay the TiC recession hollow-out and act as a protective soft coating reducing the pole-tip recession. This is obviously at the expense of an additional spacing at the head-to-tape interface of the order of 20 nm. Two kinds of wear resistant coating are tested: diamond like carbon (DLC) and superprotective layer (SPL), 10 nm and 20 to 40 nm thick, respectively. DLC coating disappears within 100 hours due possibly to abrasive and fatigue wear. SPL coatings are generally more resistant, particularly at high temperature and low humidity, possibly in relation with stain transfer. 20 nm coatings are found to rely on the substrate wear behaviour whereas 40 nm coatings are found to rely on the adhesive strength at the coating/substrate interface. These observations seem to locate the wear-driving forces 40 nm below the surface, hence indicate that for coatings in the 10 nm thickness range-· i,e. compatible with high-density recording-the substrate resistance must be taken into account. Single-phase ceramic as candidate for wear-resistant tape-bearing surface are tested in form of full-contour dummy-heads. The absence of a second phase eliminates the preferential wear observed at the AI203-TiC surface; very low wear rates and no evidence of brittle fracture are observed.

Mechanisms of transfer film formation on data recording heads

The increasing demand for high capacity data storage requires decreasing the head-to-tape gap and reducing the track width. A problem very often encountered is the development of adhesive debris on the heads at low humidity and high temperatures that can lead to an increase of space between the head and media, and thus a decrease in the playback signal. The influence of stains on the playback signal of reading heads is studied using RAW (Read After Write) tests and their influence on the wear of the heads by using indentation technique. The playback signal has been found to vary and the errors to increase as stains form a patchy pattern and grow in size to form a continuous layer. The indentation technique shows that stains reduce the wear rate of the heads. In addition, the wear tends to be more pronounced at the leading edge of the head compared to the trailing one. Chemical analysis of the stains using ferrite samples in conjunction with MP (metal particulate) tapes shows that stains contain iron particles and polymeric binder transferred from the MP tape. The chemical anchors in the binder used to grip the iron particles now react with the ferrite surface to create strong chemical bonds. At high humidity, a thin layer of iron oxyhydroxide forms on the surface of the ferrite. This soft material increases the wear rate and so reduces the amount of stain present on the heads. The stability of the binder under high humidity and under high temperature as well as the chemical reactions that might occur on the ferrite poles of the heads influences the dynamic behaviour of stains. A model of stain formation taking into account the channels of binder degradation and evolution upon different environmental conditions is proposed.

'I felt that I do live in the UK now':international students' self-reports of their English language speaking experiences on a pre-sessional programme

This article focuses on the English language experiences of a group of pre-sessional students, an under-represented group in the literature on language and education. In particular, it investigates the opportunities that such students have to use English outside the classroom, shown to be a key factor in student satisfaction with their study abroad experience. Drawing on data from questionnaires, interviews and on-line diaries, we show that students have a variety of opportunities to use English; however, these opportunities may require students to engage in complex negotiations right from the beginning of their sojourn in the UK. Micro-analysis of the data shows that agency is a key construct in understanding students' representations of their English encounters as they begin their lives in the UK. The article concludes with some suggestions as to how pre-sessional courses may develop students' linguistic and socio-cultural skills in order that they may interact successfully in English outside the classroom. © 2011 Taylor &Francis.

Inside ‘Inside View’: reflections on stimulating debate and engagement through a multimedia live theatre production on the dilemmas and issues of pre-natal screening policy and practice

Background The role of applied theatre in engaging both lay and professional publics with debate on health policy and practice is an emergent field. This paper discusses the development, production performance and discussion of ‘Inside View’.1 Objectives The objectives were to produce applied theatre from research findings of a completed study on genetic prenatal screening, exploring the dilemmas for women and health professionals of prenatal genetic screening, and to engage audiences in debate and reflection on the dilemmas of prenatal genetic screening. Methods ‘Inside View’ was developed from a multidisciplinary research study through identification of emergent themes from qualitative interviews, and development of these by the writer, theatre producer and media technologist with input from the researchers. Findings Inside View was performed in London and the Midlands to varied audiences with a panel discussion and evaluation post performance. The audiences were engaged in debate that was relevant to them professionally and personally. Knowledge translation through applied theatre is an effective tool for engaging the public but the impact subsequently is unclear. There are ethical issues of unexpected disclosure during discussion post performance and the process of transforming research findings into applied theatre requires time and trust within the multidisciplinary team as well as adequate resourcing.

TETRA mobile radios interfere with electroencephalography recording equipment

We observed an anomaly in the human electroencephalogram (EEG) associated with exposure to terrestrial trunked radio (TETRA) Radiofrequency Fields (RF). Here, we characterize the time and frequency components of the anomaly and demonstrate that it is an artefact caused by TETRA RF interfering with the EEG recording equipment and not by any direct or indirect effect on the brain.

Consensus on recording of gas permeable contact lens fit

Purpose: To develop a new schematic scheme for efficiently recording the key parameters of gas permeable contact lens (GP) fits based on current consensus. Methods: Over 100 established GP fitters and educators met to discuss the parameters proposed in educational material for evaluating GP fit and concluded on the key parameters that should be recorded. The accuracy and variability of evaluating the fluorescein pattern of GP fit was determined by having 35 experienced contact lens practitioners from across the world, grading 5 images of a range of fits and the topographer simulation of the same fits, in random, order using the proposed scheme. The accuracy of the grading was compared to objective image analysis of the fluorescein intensity of the same images. Results: The key information to record to adequately describe the fit of an GP was agreed as: the manufacturer, brand and lens parameters; settling time; comfort on a 5 point scale; centration; movement on blink on a ±2 scale; and the Primary Fluorescein Pattern in the central, mid-peripheral and edge regions of the lens averaged along the horizontal and vertical lens axes, on a ±2 scale. On average 50-60% of practitioners selected the median grade when subjectively rating fluorescein intensity and this was correlated to objective quantification (r= 0.602, p< 0.001). Objective grading suggesting horizontal median fluorescein intensity was generally symmetrical, as was the vertical meridian, but this was not the case for subjective grading. Simulated fluorescein patterns were subjectively and objectively graded as being less intense than real photographs (p< 0.01). Conclusion: GP fit recording can be standardised and simplified to enhance GP practice. © 2013 British Contact Lens Association.

Live 3D shape reconstruction, recognition and registration

We present a video-based system which interactively captures the geometry of a 3D object in the form of a point cloud, then recognizes and registers known objects in this point cloud in a matter of seconds (fig. 1). In order to achieve interactive speed, we exploit both efficient inference algorithms and parallel computation, often on a GPU. The system can be broken down into two distinct phases: geometry capture, and object inference. We now discuss these in further detail. © 2011 IEEE.

Can restricting calories help you to live longer?

Excess calorie consumption is associated with metabolic disorders and increased incidence of morbidity. Restricting calorie content, either by daily calorie restriction or intermittent fasting periods, has multiple benefits including weight loss and improved body composition. Previous research has shown that restricting calories in this way can increase longevity and slow the ageing process in laboratory animals, although only sparse data exist in human populations. This review critically evaluates the benefits of these dietary interventions on age-related decline and longevity.