Towards a realistic in vitro experience of epidural Tuohy needle insertion.

The amount of pressure exerted on the syringe and the depth of needle insertion are the two key factors for successfully carrying out epidural procedure. The force feedback from the syringe plunger is helpful in judging the loss of pressure, and the depth of the needle insertion is crucial in identifying when the needle is precisely placed in the epidural space. This article presents the development of two novel wireless devices to measure these parameters to precisely guide the needle placement in the epidural space. These techniques can be directly used on patients or implemented in a simulator for improving the safety of procedure. A pilot trial has been conducted to collect depth and pressure data with the devices on a porcine cadaver. These measurements are then combined to accurately configure a haptic device for creating a realistic in vitro experience of epidural needle insertion

The flux-dependent X-ray time lags in NGC 4051

We present an analysis of the X-ray time lags for the highly variable Seyfert 1 galaxy NGC 4051, based on a series of XMM-Newton observations taken in 2009. We investigate the Fourier frequency dependent time lags in the light curves between the 0.3--1.0 keV and 2.0--5.0 keV energy bands as a function of source flux, including simultaneous modelling of the resulting lag-frequency spectra. We find the shape of the lag-frequency spectra to vary significantly and systematically with source flux. We model the lag-frequency spectra using simple transfer functions, and find that two time lag components are required, one in each energy band. The simplest acceptable fits have only the relative contribution of the lagged component in the hard band varying with flux level, which can be associated with changes in the energy spectrum. We discuss the interpretation of these results in terms of the currently popular models for X-ray time lags.Comment: 9 pages, 4 figures. Accepted for publication in MNRA

Economic and Social Planning Aims and Methods. ESRI Memorandum Series No. 114 1975

The questions which I shall seek to answer here are the following. What is economic planning and is there a need for such planning? What are the essential components of a plan, and what are therefore the major differences in the type of plans that may be proposed? May we learn anything from the practical planning experience of other countries? In answering these questions I propose to split up the discussion on the following lines - In Section II, a planning framework is set out In Section III, the relationship between macro-plans and certain investment projects is considered. Section IV examines the theory of indicative planning and the implementation of such plans in France and Japan. Finally, in Section V we discuss the problem of why some plans are successful, whilst others fail. In the title of this paper one may find the word "social"; I intend to salve my conscience at this stage by saying that I intend to interpret social as referring to the social impact of economic planning, and leave explicit concern of problems of planning for the elderly, the sick and other such service to the last speaker of this course

A Raman Microprobe Study of Corona Ageing in a Controlled Atmosphere

Raman microprobe spectroscopy is widely used in the analysis of polymers due to its high spatial resolution and its ability to characterise the exact chemical composition of a material and, for this reason, it can be applied to study electrical ageing in solid dielectrics. For example, it enables us to probe the chemical processes involved in electrical treeing, whereby solid polymer is converted into decomposition products through a number of electrical processes [1]. This study takes a novel approach to this problem through ex-situ experiments that seek to reproduce the chemistry of electrical treeing in bulk. Plaque specimens of a range of polymers, including polyethylene, polystyrene, PEEK and silicone rubber, were subjected to surface ageing via corona discharge, and the residual products on both the sample surface and the high voltage electrode (as seen in figure 1) were characterised by Raman microprobe spectroscopy. These experiments were performed as a function of applied voltage, electrode geometry etc both in air and within a closed cell that enabled the atmosphere to be controlled and adjusted. The resulting Raman fingerprints were compared with those previously identified within electrical trees [2,3]. After corona discharge was applied to the samples, despite a large change in surface texture, no residues were seen on the sample and few chemical changes were detected via Raman spectroscopy, thus implying that erosion of the material occurs by fragmentation of the polymer. Analysis of the electrodes aged in air and nitrogen, revealed varying evidence of sp2 hybridized carbon, and fluorescence, both of which are products previously associated with the processes involved in electrical treeing. The similarity in these results and previous published works [2,3] suggest that there are common processes involved between corona surface ageing and electrical treeing especially when an inert atmosphere is used

Ultraviolet and X-ray variability of NGC 4051 over 45 days with XMM-Newton and Swift

We analyse 15 XMM-Newton observations of the Seyfert galaxy NGC 4051 obtained over 45 days to determine the ultraviolet (UV) light curve variability characteristics and search for correlated UV/X-ray emission. The UV light curve shows variability on all time scales, however with lower fractional rms than the 0.2-10 keV X-rays. On days-weeks timescales the fractional variability of the UV is Fvar ~ 8%, and on short (~ hours) timescales Fvar ~ 2%. The within-observation excess variance in 4 of the 15 UV observations was found be much higher than the remaining 11. This was caused by large systematic uncertainties in the count rate masking the intrinsic source variance. For the four "good" observations we fit an unbroken power-law model to the UV power spectra with slope -2.0 +/- 0.5. We compute the UV/X-ray Cross-correlation function for the "good" observations and find a correlation of ~ 0.5 at time lag of ~ 3 ks, where the UV lags the X-rays. We also compute for the first time the UV/X-ray Cross-spectrum in the range 0-28.5 ks, and find a low coherence and an average time lag of ~ 3 ks. Combining the 15 XMM-Newton and the Swift observations we compute the DCF over +/-40 days but are unable to recover a significant correlation. The magnitude and direction of the lag estimate from the 4 "good" observations indicates a scenario where ~ 25 % of the UV variance is caused by thermal reprocessing of the incident X-ray emission.Comment: 11 pages, 8 figures. Accepted for publication in MNRA

Electrical Treeing in Silicone Rubber

Electrical treeing has been widely studied in a range of polymeric materials. In these investigations, the morphology and PD patterns associated with the growth of electrical trees in a model transparent silicone rubber were investigated using a new system recently developed at Southampton. With increasing voltage the trees became more complex in appearance but nevertheless grow more rapidly. As the tree evolves the PD pattern becomes more intense which may provide a method of monitoring the extent of treeing in opaque samples. Raman studies indicate that treeing and breakdown channels are hollow, carbonaceous entities, a finding consistent with other studies

Monitoring Rehabilitation Parameters In Stroke Patients

This research presents the development and testing of a system for monitoring functional parameters in stroke patients undergoing rehabilitation. Benefits of real-time automated monitoring will improve measurement consistency and accuracy, reduce consultant time, earlier discharge, less hospital beds required and delivery of controlled, repetitive training. The system uses three devices: (1) the Myo gesture control armband (Thalmic Labs) to detect EMG signals, angles and acceleration; (2) the Arm Motion Monitoring and Recovery Improvement Toolkit (AMMRIT) (custom built) arm exoskeleton to monitor the whole arm angles and (3) the Kinect Sensor (Microsoft) to detect facial expressions. Stroke is the second most common cause of death and the leading cause of disability in Europe. The incidence rate is approximately 16 per 10,000 per year in the UK. One of the most effective treatments following stroke is physiotherapy which can help the patient relearn how to move the limbs. Quantifying the progress of functional recovery is technically complex because of the multi-joined structure of the arm. Currently there is no single portable system available that can provide objective measurement and analysis to monitor functional recovery for Early Supported Discharge (ESD). We developed the AMMRIT which can guide as well as assess the arm’s functional recovery of patients. In this research we combine the device with Myo armband and Kinect sensor to monitor a wide range of functional parameters to accurately assess the rehabilitation progression

Virtual Hip Replacement Simulator For 3D Printed Implants.

This research presents a virtual reality simulator for total hip replacement surgery. The simulator supports a library of 3D hip stem models for different sizes and manufacturers. The 3D hip stems can be adjusted in size and shape by parametric software and sent for 3D printing. Biocompatible materials such as titanium enable the 3D printed stems to be directly implanted on patients. Currently surgical simulation for orthopaedic procedures is not as advanced as other surgical disciplines. As a result there are only limited training simulators available for orthopaedic surgery such as total hip replacement, hip resurfacing or knee replacement. This is demanding since 66,000 hip replacements are performed annually in the UK. One area which is neglected in VR orthopaedic simulation is the digital library generation of implants. Currently orthopaedic surgeons have limited choice in terms of an exact identification of implant specific to patient requirements. We conducted a literature review of orthopaedic training simulators which found no simulators catering for this

Interpreting Ultrasound Images For Accurate Epidural Needle Insertion.

This work presents development and testing of image processing algorithms for the automatic detection of landmarks within ultrasound images. The aim was to automate ultrasound analysis, for use during the process of epidural needle insertion. For epidural insertion, ultrasound is increasingly used to guide the needle into the epidural space. Ultrasound can improve the safety of epidural and was recommended by the 2008 NICE guidelines (National Institute for Health and Care Excellence). Without using ultrasound, there is no way for the anaesthetist to observe the location of the needle within the ligaments requiring the use of their personal judgment which may lead to injury. If the needle stops short of the epidural space, the anaesthetic is ineffective. If the needle proceeds too deep, it can cause injuries ranging from headache, to permanent nerve damage or death. Ultrasound of the spine is particularly difficult, because the complex bony structures surrounding the spine limit the ultrasound beam acoustic windows. Additionally, the important structures for epidural that need to be observed are located deeper than other conventional procedures such as peripheral nerve block. This is why a low frequency, curved probe (2-5 MHz) is used, which penetrates deeper but decreases in resolution. The benefits of automating ultrasound are to enable real-time ultrasound analysis on the live video, mitigate human error, and ensure repeatability by avoiding variation in perception by different users