Intermittent antegrade cardioplegia: isolated heart preservation with the Asporto heart preservation device

Background—A major problem in procurement of donor hearts is the limited time a donor heart remains viable. After cardiectomy, ischemic hypoxia is the main cause of donor heart degradation. The global myocardial ischemia causes a cascade of oxygen radical formation that cumulates in an elevation in hydrogen ions (decrease in pH), irreversible cellular injury, and potential microvascular changes in perfusion. Objective—To determine the changes of prolonged storage times on donor heart microvasculature and the effects of intermittent antegrade perfusion. Materials and Methods—Using porcine hearts flushed with a Ribosol-based cardioplegic solution, we examined how storage time affects microvascular myocardial perfusion by using contrast-enhanced magnetic resonance imaging at a mean (SD) of 6.1 (0.6) hours (n=13) or 15.6 (0.6) hours (n=11) after cardiectomy. Finally, to determine if administration of cardioplegic solution affects pH and microvascular perfusion, isolated hearts (group 1, n=9) given a single antegrade dose, were compared with hearts (group 2, n=8) given intermittent antegrade cardioplegia (150 mL, every 30 min, 150 mL/min) by a heart preservation device. Khuri pH probes in left and right ventricular tissue continuously measured hydrogen ion levels, and perfusion intensity on magnetic resonance images was plotted against time. Results—Myocardial perfusion measured via magnetic resonance imaging at 6.1 hours was significantly greater than at 15.6 hours (67% vs 30%, P= .00008). In group 1 hearts, the mean (SD) for pH at the end of 6 hours decreased to 6.2 (0.2). In group 2, hearts that received intermittent antegrade cardioplegia, pH at the end of 6 hours was higher at 6.7 (0.3) (P=.0005). Magnetic resonance imaging showed no significant differences between the 2 groups in contrast enhancement (group 1, 62%; group 2, 40%) or in the wet/dry weight ratio. Conclusion—Intermittent perfusion maintains a significantly higher myocardial pH than does a conventional single antegrade dose. This difference may translate into an improved quality of donor hearts procured for transplantation, allowing longer distance procurement, tissue matching, improved outcomes for transplant recipients, and ideally a decrease in transplant-related costs.

Portable smartphone quantitation of prostate specific antigen (PSA) in a fluoropolymer microfluidic device

We present a new, power-free and flexible detection system named MCFphone for portable colorimetric and fluorescence quantitative sandwich immunoassay detection of prostate specific antigen (PSA). The MCFphone is composed by a smartphone integrated with a magnifying lens, a simple light source and a miniaturised immunoassay platform, the Microcapillary Film (MCF). The excellent transparency and flat geometry of fluoropolymer MCF allowed quantitation of PSA in the range 0.9 to 60 ng/ml with < 7 % precision in 13 minutes using enzymatic amplification and a chromogenic substrate. The lower limit of detection was further improved from 0.4 to 0.08 ng/ml in whole blood samples with the use of a fluorescence substrate. The MCFphone has shown capable of performing rapid (13 to 22 minutes total assay time) colorimetric quantitative and highly sensitive fluorescence tests with good %Recovery, which represents a major step in the integration of a new generation of inexpensive and portable microfluidic devices with commercial immunoassay reagents and off-the-shelf smartphone technology.

Development of a wearable assistive soft robotic device for elbow rehabilitation

The loss of motor function at the elbow joint can result as a consequence of stroke. Stroke is a clinical illness resulting in long lasting neurological deficits often affecting somatosensory and motor cortices. More than half of those that recover from a stroke survive with disability in their upper arm and need rehabilitation therapy to help in regaining functions of daily living. In this paper, we demonstrated a prototype of a low-cost, ultra-light and wearable soft robotic assistive device that could aid administration of elbow motion therapies to stroke patients. In order to assist the rotation of the elbow joint, the soft modules which consist of soft wedge-like cellular units was inflated by air to produce torque at the elbow joint. Highly compliant rotation can be naturally realised by the elastic property of soft silicone and pneumatic control of air. Based on the direct visual-actuation control, a higher control loop utilised visual processing to apply positional control, the lower control loop was implemented by an electronic circuit to achieve the desired pressure of the soft modules by Pulse Width Modulation. To examine the functionality of the proposed soft modular system, we used an anatomical model of the upper limb and performed the experiments with healthy participants.

Assessment of the CMD Mini-Explorer, a new low-frequency multi-coil electromagnetic device, for archaeological investigations

In this article we assess the abilities of a new electromagnetic (EM) system, the CMD Mini-Explorer, for prospecting of archaeological features in Ireland and the UK. The Mini-Explorer is an EM probe which is primarily aimed at the environmental/geological prospecting market for the detection of pipes and geology. It has long been evident from the use of other EM devices that such an instrument might be suitable for shallow soil studies and applicable for archaeological prospecting. Of particular interest for the archaeological surveyor is the fact that the Mini-Explorer simultaneously obtains both quadrature (‘conductivity’) and in-phase (relative to ‘magnetic susceptibility’) data from three depth levels. As the maximum depth range is probably about 1.5 m, a comprehensive analysis of the subsoil within that range is possible. As with all EM devices the measurements require no contact with the ground, thereby negating the problem of high contact resistance that often besets earth resistance data during dry spells. The use of the CMD Mini-Explorer at a number of sites has demonstrated that it has the potential to detect a range of archaeological features and produces high-quality data that are comparable in quality to those obtained from standard earth resistance and magnetometer techniques. In theory the ability to measure two phenomena at three depths suggests that this type of instrument could reduce the number of poor outcomes that are the result of single measurement surveys. The high success rate reported here in the identification of buried archaeology using a multi-depth device that responds to the two most commonly mapped geophysical phenomena has implications for evaluation style surveys. Copyright © 2013 John Wiley & Sons, Ltd.

A methodology to measure the environmental impact of ICT operating systems across different device platforms

Abstract: A new methodology was created to measure the energy consumption and related green house gas (GHG) emissions of a computer operating system (OS) across different device platforms. The methodology involved the direct power measurement of devices under different activity states. In order to include all aspects of an OS, the methodology included measurements in various OS modes, whilst uniquely, also incorporating measurements when running an array of defined software activities, so as to include OS application management features. The methodology was demonstrated on a laptop and phone that could each run multiple OSs, results confirmed that OS can significantly impact the energy consumption of devices. In particular, the new versions of the Microsoft Windows OS were tested and highlighted significant differences between the OS versions on the same hardware. The developed methodology could enable a greater awareness of energy consumption, during both the software development and software marketing processes.

Capillary assay device with internal hydrophilic coating

The present invention provides assay devices having a unitary body with an exterior surface, the unitary body being substantially transparent to visible light and formed from a material having a refractive index in the range 1.26 to 1.40, the refractive index being measured at 20 °C with light of wavelength 589 nm, and wherein the unitary body is formed from a hydrophobic material, and at least two capillary bores extending internally along the unitary body, wherein at least a portion of the surface of each capillary bore includes a hydrophilic layer for retaining an assay reagent, and wherein the hydrophilic layer is also substantially transparent to visible light to allow optical interrogation of the capillary bores through the capillary wall. The present invention also provides assay systems including such assay devices, methods of performing an assay using such assay devices and method of method for manufacturing such assay devices.

Design and analysis of a haptic device design for large and fast movements

Haptic devices tend to be kept small as it is easier to achieve a large change of stiffness with a low associated apparent mass. If large movements are required there is a usually a reduction in the quality of the haptic sensations which can be displayed. The typical measure of haptic device performance is impedance-width (z-width) but this does not account for actuator saturation, usable workspace or the ability to do rapid movements. This paper presents the analysis and evaluation of a haptic device design, utilizing a variant of redundant kinematics, sometimes referred to as a macro-micro configuration, intended to allow large and fast movements without loss of impedance-width. A brief mathematical analysis of the design constraints is given and a prototype system is described where the effects of different elements of the control scheme can be examined to better understand the potential benefits and trade-offs in the design. Finally, the performance of the system is evaluated using a Fitts’ Law test and found to compare favourably with similar evaluations of smaller workspace devices.