A RED CELL DEFORMATION MODEL FOR HEMOLYSIS IN CROSS FLOW MEMBRANE PLASMAPHERESIS

Hemolysis is a serious potential problem in continuous flow membrane plasmapheresis, which is increasingly used for plasma collection and for therapeutic treatment of a variety of immunologic and metabolic disorders. Previously developed theory, which is based upon the notion that red cells hemolyze upon contact with the membrane, does not correctly predict experimental observations of the effects of transmembrane pressure drop, membrane pore size, and wall shear rate on hemolysis in this process. We propose that hemolysis occurs by deformation of red blood cells as they are forced into membrane pores. The cells hemolyze if the strain in the cell membrane caused by this deformation is sufficient to rupture the cell membrane. This strain is a function not only of the transmembrane pressure drop which forces the cells into the pores but also of the residence time for the cells in the pores, which is assumed to be a function of wall shear rate. Predictions of the model agree well with data. The model provides both a fundamental understanding of hemolysis and a rational basis for the design of improved plasmapheresis devices.     

AN OPTIMIZATION METHOD TO DESIGN HYDRAULIC NETWORKS

Nonlinear programming is applied to the solution of hydraulic network problems. The significant differences between the proposed optimization method and other conventional methods are that this method can solve problems with mixed unknowns (e.g. pipe sizes, discharges and pressures), it can optimize solutions involving unknowns defined by inequalities (e.g. specifled minimum discharge and pressure values), it can handle network control problems such as required valve adjustments or in-line booster pump needs, and it may solve problems of networks with continuous discharge distribution along the pipes.     

Crossed orbit interferometry: theory and experimental results from SIR-B

Abstract

In a conventional imaging radar interferometer, two receiving antennas separated slightly in the cross-track direction view the same scene and altimetry information is deduced from the phase differences between the corresponding pixels in each image. It is possible to perform the same measurements with only one antenna by making two images of the scene on two separate passes; for SIR-B this involved imaging on two separate orbits. If the two orbits are parallel and separated in the cross-track direction, altitude information is derived exactly as in the two-antenna interferometer and the baseline is determined by the orbit separation. For the available SIR-B data, however, the orbits were skewed, which substantially increases the difficulty of finding altitudes. Since the orbits were not exactly parallel, the antenna on one orbit was pointed slightly forward or backward compared to the other; this was compensated for in the azimuth processing. Furthermore, the skew gave the images a cross-track displacement that increased linearly with azimuth distance, which was removed by resampling and stretching one of the images. Because of the skewing, the baseline increased with distance from the crossing point and theory indicates that altitude variation appears as a change in the along-track position of a given pixel. This is borne out in the experimental data which is then used to construct a coarse altitude map. Additionally, the phase difference of each overlaid pixel is related to the altitude in a complicated way. An algorithm was developed to invert this relationship, the results of which were then used to construct a more refined altitude map.     

A GIS AND WEB-BASED DECISION SUPPORT TOOL FOR THE MANAGEMENT OF URBAN SOILS

Soils are fundamental to urban environmental quality. They have aesthetic and recreational functions in parks and gardens and contribute to the preservation of biodiversity. They also directly influence citizens' health. This paper describes the initial development of a decision support tool (DST) to appraise the urban soil resource and its valuable functions within a wide range of urban environments. It is aimed to provide assistance to local, national, and European authorities in the optimum planning and sustainable management of their soils resources. The DST is an integrated information technology system based on a spatially distributed environmental database management system of soil quality parameters and soil characteristics together with broader environmental factors. The integration is achieved through the implementation of the DST within the framework of a geographical information system coupled with risk assessment, pollution decay, and other models including the handling of “soft” data. The DST will be web-based, allowing wide access to all stakeholders and citizens, providing on-line forums for consultations, and exchange of information and feedback among stakeholders. It is designed to support true transparency in decision making at the local and international levels. The paper focuses specifically on the development of the system architecture of the DST.     

Collaboration and Trust in Healthcare Innovation: The eDiaMoND Case Study

This paper presents findings from an investigation into requirements for collaboration in e-Science in the context of eDiaMoND, a Grid-enabled prototype system intended in part to support breast cancer screening. Detailed studies based on ethnographic fieldwork reveal the importance of accountability and visibility of work for trust and for the various forms of ‘practical ethical action’ in which clinicians are seen to routinely engage in this setting. We discuss the implications of our findings, specifically for the prospect of using distributed screening to make more effective use of scarce clinical skills and, more generally, for realising the Grid’s potential for sharing data within and across institutions. Understanding how to afford trust and to provide adequate support for ethical concerns relating to the handling of sensitive data is a particular challenge for e-Health systems and for e-Science in general. Future e-Health and e-Science systems will need to be compatible with the ways in which trust is achieved, and practical ethical actions are realised and embedded within work practices.     

Determination of acid phosphatase activity in heat treated milks by the Fluorophos Test System

The Fluorophos Test System® for measurement of acid phosphatase in fruit juices was used to determine the survival of acid phosphatase in heat treated cows' milk. The method was found to be applicable to milk, with reproducibility improved by use of a vortex mixer. It was sufficiently sensitive to provide a quantitative measure of the activity surviving heat treatments from 75 to 88° C for 15 seconds and would thus provide a rapid method for checking more severe heat treatments_ for instance, those used to enhance the destruction of Mycobacterium paratuberculosis.     

The effective resolution element of Landsat Thematic Mapper

Abstract

As part of the U.K.'s contribution to NASA's Landsat [mage Data Quality Analysis (LIDQA) programme the system performance of the Thematic Mapper (TM) scanner has been studied by the determination of the Effective Resolution Element (ERE), a measure of its spatial resolution. Two methods have been used, the first by a simulation of the TM's spatial responses in an analytical model and the second by measurements of water bodies on a selected Landsat-5 TM scene. Bands 1-4 of the Thematic Mappers of both Landsat-4 and Landsal-5 have an effective resolution element by the former method of 52 m. This compares with a value of 122 m for band 4, near-infrared, of the Multispectral Scanner (MSS) by the same method. An image-derived value, by the latter method, for band 4 of the Landsat-5 TM scene is approximately 75 m. This increase in the ERE over the sensor-only value is attributed to additional factors within the imagery such as the pixel sampling of the scene, ground segment processing and the contribution of atmospheric effects. The image-derived measure of the ERE will give a useful indication of the size of targets that can be recorded to a given radiometric accuracy and can thus determine the type of informational classes that may be utilized from present methods of automated classifications of remotely-sensed data.     

CONTINUED FRACTIONS: YET ANOTHER TOOL TO OVERCOME THE CURSE OF DIMENSIONALITY

We provide a rapid prediction method, in which a larger number of antecedents is accounted for than is currently considered. To this end, we encode the successive (possibly rescaled) values of a time series, as the partial quotients of a continued fraction, resulting in a number from the unit interval. The accuracy of a rule-based system utilizing this coding is investigated to some extent. Qualitative criteria for the applicability of the algorithm are formulated.