High-NA lensless coherent imager as a building block for a synthetic aperture interferometry array

In digital holography, the field of view (FOV) and lateral resolution are limited by the pixel pitch and sensor dimensions, respectively. A large numerical aperture can be synthesized to increase the FOV and spatial resolution by coherently combining low resolution holograms obtained for different illumination and/or observation directions. This is known as Synthetic Aperture Interferometry (SAI) and in this work we describe the design, construction, calibration and testing of high numerical aperture compact coherent imagers (CI) which constitute the optical building block of a multi-sensor SAI array. The CIs consist of a photodetector array, a highly divergent reference beam close to it and an aperture that acts as a spatial filter to prevent aliasing of the digital holograms. We explore different optical designs to produce a highly divergent reference beam close to the sensor, including bulk optics, micro-optics, and ion beam milled optical fibres. An optimization approach is used to characterize the reference wavefront for accurate digital reconstructions of the scattered field first at the aperture plane and then at the object plane. The performance of a compact CI is demonstrated by reconstructing an object 76 mm wide at 80 mm from the sensor, which corresponds to a numerical aperture NA>0.5

Effects of random vibration in high-speed phase-shifting speckle pattern interferometry

The influence of random vibrations on a dynamic phase shifting speckle pattern interferometer, in which phase difference evaluation is performed using temporal phase shifting and temporal phase unwrapping, is investigated by means of experiments and numerical simulations. A well-defined velocity spectral density function, typical of the spectra found under non-vibration-isolated conditions, is used throughout. Five phase-shifting formulae are studied, with camera framing rates (1,2 and 4 kHz) typical of current dynamic speckle pattern interferometers. Two main aspects were evaluated: firstly the unwrapping reliability, and secondly the noise induced in the phase maps by the vibration. The former was found to be a significant constraint, even for peak velocities well below the Nyquist velocity limit of the interferometer, and is therefore likely to be more important than the latter in many applications. Three analytical criteria for determining the expected unwrapping success rate are proposed and their predictions compared with the measured values. It is demonstrated that shorter sampling windows and higher framing rates are preferred in order to increase the unwrapping success rate, but that longer windows reduce the root mean square error in the phase change maps due to the vibration

"It's just horrible": a qualitative study of patients' and carers' experiences of bowel dysfunction in Multiple Sclerosis

Background: Around 50% of people with multiple sclerosis (MS) experience neurogenic bowel dysfunction (constipation and / or faecal incontinence), reducing quality of life and increasing carer burden. No previous qualitative studies have explored the experiences of bowel problems in people with MS, or the views of their family carers. Objective: To understand 'what it is like' to live with bowel dysfunction and the impact this has on people with MS and carers. Methods: Using exploratory qualitative methods, 47 semi-structured interviews were conducted with participants recruited from specialist hospital clinics and community sources using purposive and chain-referral sampling. Data were analysed using a pragmatic inductive-deductive method. Results: Participants identified multiple psychological, physical and social impacts of bowel dysfunction. Health care professional support ranged from empathy and appropriate onward referral, to lack of interest or not referring to appropriate services. Participants want bowel issues to be discussed more openly, with clinicians instigating a discussion early after MS diagnosis and repeating enquiries regularly. Conclusions: Bowel dysfunction impacts on the lives of people with MS and their carers; their experience with care services is often unsatisfactory. Understanding patient and carer preferences about management of bowel dysfunction can inform clinical care and referral pathways

Consensus review of best practice of transanal irrigation in adults

Study design: Review article. Objectives: To provide a consensus expert review of the treatment modality for transanal irrigation (TAI). Methods: A consensus group of specialists from a range of nations and disciplines who have experience in prescribing and monitoring patients using TAI worked together assimilating both the emerging literature and rapidly accruing clinical expertise. Consensus was reached by a round table discussion process, with individual members leading the article write-up in the sections where they had particular expertise. Results: Detailed trouble-shooting tips and an algorithm of care to assist professionals with patient selection, management and follow-up was developed. Conclusion: This expert review provides a practical adjunct to training for the emerging therapeutic area of TAI. Careful patient selection, directly supervised training and sustained follow-up are key to optimise outcomes with the technique. Adopting a tailored, stepped approach to care is important in the heterogeneous patient groups to whom TAI may be applied. Sponsorship: The review was financially supported by Coloplast A/S. Spinal Cord (2013) 51, 732–738; doi:10.1038/sc.2013.86; published online 20 August 201

What Works to Improve and Manage Fecal Incontinence in Care Home Residents Living With Dementia? A Realist Synthesis of the Evidence.

The prevalence of fecal incontinence (FI) in care homes is estimated to range from 30% to 50%. There is limited evidence of what is effective in the reduction and management of FI in care homes. Using realist synthesis, 6 potential program theories of what should work were identified. These addressed clinician-led support, assessment, and review; the contribution of teaching and support for care home staff on how to reduce and manage FI; addressing the causes and prevention of constipation; how cognitive and physical capacity of the resident affects outcomes; how the potential for recovery, reduction, and management of FI is understood by those involved; and how the care of people living with dementia and FI is integral to the work patterns of the care home and its staff. Dementia was a known risk factor for fecal incontinence (FI), but how it affected uptake of different interventions or the dementia specific continence and toileting skills staff require, were not addressed in the literature. There was a lack of dementia-specific evidence on continence aids. Most care home residents with FI will be doubly incontinent; there is, therefore, limited value in focusing solely on FI or single causes, such as constipation. Medical and nursing support for continence care is an important resource, but it is unhelpful to create a distinction between what is continence care and what is personal or intimate care. Prompted toileting is an approach that may be particularly beneficial for some residents. Valuing the intimate and personal care work unqualified and junior staff provide to people living with dementia and reinforcement of good practice in ways that are meaningful to this workforce are important clinician-led activities. Providing dementia-sensitive continence care within the daily work routines of care homes is key to helping to reduce and manage FI for this population

Neurogenic mechanisms in bladder and bowel ageing

The prevalence of both urinary and faecal incontinence, and also chronic constipation, increases with ageing and these conditions have a major impact on the quality of life of the elderly. Management of bladder and bowel dysfunction in the elderly is currently far from ideal and also carries a significant financial burden. Understanding how these changes occur is thus a major priority in biogerontology. The functions of the bladder and terminal bowel are regulated by complex neuronal networks. In particular neurons of the spinal cord and peripheral ganglia play a key role in regulating micturition and defaecation reflexes as well as promoting continence. In this review we discuss the evidence for ageing-induced neuronal dysfunction that might predispose to neurogenic forms of incontinence in the elderly

Isolation of adenoviruses from cases of epidemic keratoconjunctivitis in Singapore

American Journal of Ophthalmology553575-583AJOP