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Terms modified by Portable Selected AbstractsVisualisation of needle position using ultrasonographyANAESTHESIA, Issue 2 2006G. A. Chapman Summary Anaesthetists and intensivists spend a considerable proportion of their working time inserting needles and catheters into patients. In order to access deeper structures like central veins and nerves, they have traditionally relied on surface markings to guide the needle into the correct position. However, patients may present challenges due to anatomical abnormalities and size. Irrespective of the skill of the operator, there is the ever-present risk of needle misplacement with the potential of damage to structures like arteries, nerve bundles and pleura. Repeated attempts, even if ultimately successful, cause patient suffering and probably increase the risk of infection and other long term complications. Portable and affordable, high-resolution ultrasound scanners, has accelerated the interest in the use of ultrasound guidance for interventional procedures. Ultrasound guidance offers several advantages including a greater likelihood of success, fewer complications and less time spent on the procedure. Even if the target structure is identified correctly there is still the challenge to place the needle or other devices in the optimum site. The smaller and deeper the target, the greater the challenge and potential usefulness of ultrasound guidance. As a result of limited training in the use of ultrasound we believe that many clinicians fail to use it to its full potential. A lack of understanding, with regard to imaging the location of the needle tip remains a major obstacle. Needle visualisation and related topics form the basis for this review. [source] OpenUH: an optimizing, portable OpenMP compilerCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 18 2007Chunhua Liao Abstract OpenMP has gained wide popularity as an API for parallel programming on shared memory and distributed shared memory platforms. Despite its broad availability, there remains a need for a portable, robust, open source, optimizing OpenMP compiler for C/C++/Fortran 90, especially for teaching and research, for example into its use on new target architectures, such as SMPs with chip multi-threading, as well as learning how to translate for clusters of SMPs. In this paper, we present our efforts to design and implement such an OpenMP compiler on top of Open64, an open source compiler framework, by extending its existing analysis and optimization and adopting a source-to-source translator approach where a native back end is not available. The compilation strategy we have adopted and the corresponding runtime support are described. The OpenMP validation suite is used to determine the correctness of the translation. The compiler's behavior is evaluated using benchmark tests from the EPCC microbenchmarks and the NAS parallel benchmark. Copyright © 2007 John Wiley & Sons, Ltd. [source] Parallel divide-and-conquer scheme for 2D Delaunay triangulationCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 12 2006Min-Bin Chen Abstract This work describes a parallel divide-and-conquer Delaunay triangulation scheme. This algorithm finds the affected zone, which covers the triangulation and may be modified when two sub-block triangulations are merged. Finding the affected zone can reduce the amount of data required to be transmitted between processors. The time complexity of the divide-and-conquer scheme remains O(n log n), and the affected region can be located in O(n) time steps, where n denotes the number of points. The code was implemented with C, FORTRAN and MPI, making it portable to many computer systems. Experimental results on an IBM SP2 show that a parallel efficiency of 44,95% for general distributions can be attained on a 16-node distributed memory system. Copyright © 2006 John Wiley & Sons, Ltd. [source] Bridging the language gap in scientific computing: the Chasm approachCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 2 2006C. E. Rasmussen Abstract Chasm is a toolkit providing seamless language interoperability between Fortran 95 and C++. Language interoperability is important to scientific programmers because scientific applications are predominantly written in Fortran, while software tools are mostly written in C++. Two design features differentiate Chasm from other related tools. First, we avoid the common-denominator type systems and programming models found in most Interface Definition Language (IDL)-based interoperability systems. Chasm uses the intermediate representation generated by a compiler front-end for each supported language as its source of interface information instead of an IDL. Second, bridging code is generated for each pairwise language binding, removing the need for a common intermediate data representation and multiple levels of indirection between the caller and callee. These features make Chasm a simple system that performs well, requires minimal user intervention and, in most instances, bridging code generation can be performed automatically. Chasm is also easily extensible and highly portable. Copyright © 2005 John Wiley & Sons, Ltd. [source] JOPI: a Java object-passing interfaceCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7-8 2005Jameela Al-Jaroodi Abstract Recently there has been an increasing interest in developing parallel programming capabilities in Java to harness the vast resources available in clusters, grids and heterogeneous networked systems. In this paper, we introduce a Java object-passing interface (JOPI) library. JOPI provides Java programmers with the necessary functionality to write object-passing parallel programs in distributed heterogeneous systems. JOPI provides a Message Passing Interface (MPI)-like interface that can be used to exchange objects among processes. In addition to the well-known benefits of the object-oriented development model, using objects to exchange information in JOPI is advantageous because it facilitates passing complex structures and enables the programmer to isolate the problem space from the parallelization problem. The run-time environment for JOPI is portable, efficient and provides the necessary functionality to deploy and execute parallel Java programs. Experiments were conducted on a cluster system and a collection of heterogeneous platforms to measure JOPI's performance and compare it with MPI. The results show good performance gains using JOPI. Copyright © 2005 John Wiley & Sons, Ltd. [source] Ibis: a flexible and efficient Java-based Grid programming environmentCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7-8 2005Rob V. van Nieuwpoort Abstract In computational Grids, performance-hungry applications need to simultaneously tap the computational power of multiple, dynamically available sites. The crux of designing Grid programming environments stems exactly from the dynamic availability of compute cycles: Grid programming environments (a) need to be portable to run on as many sites as possible, (b) they need to be flexible to cope with different network protocols and dynamically changing groups of compute nodes, while (c) they need to provide efficient (local) communication that enables high-performance computing in the first place. Existing programming environments are either portable (Java), or flexible (Jini, Java Remote Method Invocation or (RMI)), or they are highly efficient (Message Passing Interface). No system combines all three properties that are necessary for Grid computing. In this paper, we present Ibis, a new programming environment that combines Java's ,run everywhere' portability both with flexible treatment of dynamically available networks and processor pools, and with highly efficient, object-based communication. Ibis can transfer Java objects very efficiently by combining streaming object serialization with a zero-copy protocol. Using RMI as a simple test case, we show that Ibis outperforms existing RMI implementations, achieving up to nine times higher throughputs with trees of objects. Copyright © 2005 John Wiley & Sons, Ltd. [source] Reliability of the V-scope system in the measurement of arm movement in children with obstetric brachial plexus palsyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 11 2006Andrea E Bialocerkowski PhD BApp Sc (Physio) MApp Sc (Physio) This study reports on a novel methodology using the V-scope to quantify elbow and shoulder movement in young children with obstetric brachial plexus palsy (OBPP), and the intra-and interreliability of this method. The V-scope, a portable, inexpensive movement analysis system, was configured in an L-shape, with two transmitting towers placed on the floor and one 1.35m off the ground. These towers received ultrasonic pulses from buttons that were placed over standardized landmarks of the child's trunk, chest, and upper limb. Two physiotherapists (a paediatric and a generalist) facilitated the maximum range of active elbow flexion/extension and shoulder abduction/flexion in 30 children with OBPP (18 females, 12 males; age range 6mo-4y 7mo; mean age 2y 6mo [SD 1y 2mo]). Assessments were conducted on two occasions, one week apart. The V-scope was found to be feasible to use by a specialist and a generalist physiotherapist, demonstrating moderate to high reliability coefficients, small measurement errors, and lack of missing data. The pediatric physiotherapist was more reliable in measuring elbow and shoulder movement compared with the generalist physiotherapist, which suggests that the same experienced, pediatric physiotherapist should assess elbow and shoulder movement across all occasions of testing. [source] Measurement and data analysis methods for field-scale wind erosion studies and model validation,EARTH SURFACE PROCESSES AND LANDFORMS, Issue 11 2003Ted M. Zobeck Abstract Accurate and reliable methods of measuring windblown sediment are needed to con,rm, validate, and improve erosion models, assess the intensity of aeolian processes and related damage, determine the source of pollutants, and for other applications. This paper outlines important principles to consider in conducting ,eld-scale wind erosion studies and proposes strategies of ,eld data collection for use in model validation and development. Detailed discussions include consideration of ,eld characteristics, sediment sampling, and meteorological stations. The ,eld shape used in ,eld-scale wind erosion research is generally a matter of preference and in many studies may not have practical signi,cance. Maintaining a clear non-erodible boundary is necessary to accurately determine erosion fetch distance. A ,eld length of about 300 m may be needed in many situations to approach transport capacity for saltation ,ux in bare agricultural ,elds. Field surface conditions affect the wind pro,le and other processes such as sediment emission, transport, and deposition and soil erodibility. Knowledge of the temporal variation in surface conditions is necessary to understand aeolian processes. Temporal soil properties that impact aeolian processes include surface roughness, dry aggregate size distribution, dry aggregate stability, and crust characteristics. Use of a portable 2 tall anemometer tower should be considered to quantify variability of friction velocity and aerodynamic roughness caused by surface conditions in ,eld-scale studies. The types of samplers used for sampling aeolian sediment will vary depending upon the type of sediment to be measured. The Big Spring Number Eight (BSNE) and Modi,ed Wilson and Cooke (MWAC) samplers appear to be the most popular for ,eld studies of saltation. Suspension ,ux may be measured with commercially available instruments after modi,cations are made to ensure isokinetic conditions at high wind speeds. Meteorological measurements should include wind speed and direction, air temperature, solar radiation, relative humidity, rain amount, soil temperature and moisture. Careful consideration of the climatic, sediment, and soil surface characteristics observed in future ,eld-scale wind erosion studies will ensure maximum use of the data collected. Copyright © 2003 John Wiley & Sons, Ltd. [source] The Pocket Echocardiograph: Validation and FeasibilityECHOCARDIOGRAPHY, Issue 7 2010Benjamin C. Culp M.D. Background: A new, miniaturized ultrasound device, the pocket echocardiograph (PE), is highly portable and can be carried inside a lab-coat pocket. Studies of this device are limited and have not examined the use by novice echocardiographers. We hypothesize that a novice echocardiographer can use PE to produce interpretable cardiac images, and that both novice and expert echocardiographers can use PE to accurately quantify ejection fraction. Methods: Unselected subjects (n = 40) in an echocardiography laboratory underwent blinded formal transthoracic echocardiography (TTE) and PE (Acuson P10, Siemens, Mountain View, CA, USA). A cardiology fellow with 2 months of echocardiography training acquired PE images. The fellow and an experienced echocardiographer interpreted the PE studies offline in a blinded fashion. To assess adequacy, studies were graded as technically adequate, limited, or inadequate. A visual estimation of ejection fraction was made. Comparisons were made to the formal reported TTE. Results: Subjects were heterogeneous, 43% male; age 64 ± 17 years, and ejection fraction 52.4%± 12.3%. All PE studies were interpretable, and the vast majority of PE and TTE images were considered technically adequate (77.5% and 85% respectively; P = 0.32). Ejection fraction showed a good correlation, bias, and limits of agreement for the fellow's interpretation (r = 0.78, ,5.9%, ±16.6%) with stronger association for the experienced echocardiographer (r = 0.88, ,0.8%, ±11.4%). Conclusion: Novice echocardiographers using the PE can produce adequate quality images. Both expert and novice echocardiographers can use PE to quantify ejection fraction over a broad range of patients. The device's low cost and portability may greatly expand the availability of bedside echocardiography for routine or urgent cardiovascular assessment. (Echocardiography 2010;27:759-764) [source] The Effect of Hemodialysis on Left Ventricular Outflow Tract GradientECHOCARDIOGRAPHY, Issue 6 2010Pawel Petkow Dimitrow M.D. Background: The aim of the study was to assess the effect of hemodialysis (HD) on left ventricular outflow tract gradient (LVOTG) measured both in supine and upright position (provocative maneuver to unload LV cavity by rapid preload reduction). Supine/standing echocardiography was performed immediately before and immediately after HD. For additional verification of the hypothesis about preload-dependence of LVOTG, the echocardiograms after long (2-day delay HD due to weekend) versus short (usual 1-day) pause between HDs were compared. Methods: Forty-one patients on chronic HD (mean age 44 ± 11 years) were examined using a portable hand-carried echocardiograph. In accordance with the prestudy assumption the ultrafiltration volume was significantly greater during HD after a long pause in comparison to HD after a short pause (3707 ± 2826 mL vs. 2665 ± 1152 mL P < 0.05). Results: After a long pause, the mean value of LVOTG at the pre-HD was mildly increased in the supine position and remained at a similar level in the upright position (13.1 ± 6.1 vs. 13.6 ± 9.1 mmHg). Mean LVOTG at the post-HD in the supine position was similar to pre-HD, however the orthostatic stress test induced a significant increase of LVOTG (13.9 ± 15.2 vs. 18.2 ± 19.9 mmHg P < 0.05). After a short pause at the pre-HD the LVOTG in the supine position and after the orthostatic provocation was very similar to measurements after long pause (13.3 ± 9.1 vs. 13.3 ± 10.8 mmHg). At the post-HD the mean value of LVOTG increased during upright posture but the differences were of borderline significance (13.2 ± 6.6 vs. 17.9 ± 18.6 mmHg P = 0.052). Conclusions: HD predisposed to standing-provoked LVOTG especially when a long pause (2 days) between HDs induced a greater weight gain and subsequently a larger volume of ultrafiltration was needed to reduce hypervolemia. (Echocardiography 2010;27:603-607) [source] Electrochemical Detection for Capillary Electrophoresis Microchips: A ReviewELECTROANALYSIS, Issue 13 2005Joseph Wang Abstract Electrochemistry detection offers considerable promise for capillary-electrophoresis (CE) microchips, with features that include remarkable sensitivity, portability, independence of optical path length or sample turbidity, low cost and power requirements, and high compatibility with modern micromachining technologies. This article highlights key strategies in controlled-potential electrochemical detectors for CE microchip systems, along with recent advances and directions. Subjects covered include the design of the electrochemical detection system, its requirements and operational principles, common electrode materials, isolation from the separation voltage, derivatization reactions, typical applications, and future prospects. It is expected that electrochemical detection will become a powerful tool for CE microchip systems and will lead to the creation of truly portable (and possibly disposable) devices. [source] Microfluidic tectonics platform: A colorimetric, disposable botulinum toxin enzyme-linked immunosorbent assay systemELECTROPHORESIS, Issue 10-11 2004Jaisree Moorthy Abstract A fabrication platform for realizing integrated microfluidic devices is discussed. The platform allows for creating specific microsystems for multistep assays in an ad hoc manner as the components that perform the assay steps can be created at any location inside the device via in situ fabrication. The platform was utilized to create a prototype microsystem for detecting botulinum neurotoxin directly from whole blood. Process steps such as sample preparation by filtration, mixing and incubation with reagents was carried out on the device. Various microfluidic components such as channel network, valves and porous filter were fabricated from prepolymer mixture consisting of monomer, cross-linker and a photoinitiator. For detection of the toxoid, biotinylated antibodies were immobilized on streptavidin-functionalized agarose gel beads. The gel beads were introduced into the device and were used as readouts. Enzymatic reaction between alkaline phosphatase (on secondary antibody) and substrate produced an insoluble, colored precipitate that coated the beads thus making the readout visible to the naked eye. Clinically relevant amounts of the toxin can be detected from whole blood using the portable enzyme-linked immunosorbent assay (ELISA) system. Multiple layers can be realized for effective space utilization and creating a three-dimensional (3-D) chaotic mixer. In addition, external materials such as membranes can be incorporated into the device as components. Individual components that were necessary to perform these steps were characterized, and their mutual compatibility is also discussed. [source] EFNS guideline on neuroimaging in acute stroke.EUROPEAN JOURNAL OF NEUROLOGY, Issue 12 2006Report of an EFNS task force Neuroimaging techniques are necessary for the evaluation of stroke, one of the leading causes of death and neurological impairment in developed countries. The multiplicity of techniques available has increased the complexity of decision making for physicians. We performed a comprehensive review of the literature in English for the period 1965,2005 and critically assessed the relevant publications. The members of the panel reviewed and corrected an initial draft, until a consensus was reached on recommendations stratified according to the European Federation of Neurological Societies (EFNS) criteria. Non-contrast computed tomography (CT) scan is the established imaging procedure for the initial evaluation of stroke patients. However, magnetic resonance imaging (MRI) has a higher sensitivity than CT for the demonstration of infarcted or ischemic areas and depicts well acute and chronic intracerebral hemorrhage. Perfusion and diffusion MRI together with MR angiography (MRA) are very helpful for the acute evaluation of patients with ischemic stroke. MRI and MRA are the recommended techniques for screening cerebral aneurysms and for the diagnosis of cerebral venous thrombosis and arterial dissection. For the non-invasive study of extracranial vessels, MRA is less portable and more expensive than ultrasonography but it has higher sensitivity and specificity for carotid stenosis. Transcranial Doppler is very useful for monitoring arterial reperfusion after thrombolysis, for the diagnosis of intracranial stenosis and of right-to-left shunts, and for monitoring vasospasm after subarachnoid hemorrhage. Currently, single photon emission computed tomography and positron emission tomography have a more limited role in the evaluation of the acute stroke patient. [source] Miniaturization of Fluorescence Microscopes Using Fibre OpticsEXPERIMENTAL PHYSIOLOGY, Issue 6 2002Fritjof Helmchen In both medical research and diagnostics characterization of biological tissue on the cellular level relies on high-resolution optical microscopy. In most cases, however, tissue is excised for microscopic investigation, in part because conventional microscopes are bulky instruments. Imaging of cells in the intact living organism has been difficult. Over the last decade several groups have developed miniature confocal microscopes that use fibre optics to deliver light to the specimen and to measure either reflected or excited fluorescence light. In addition, two-photon excitation recently has been employed in a small portable ,fibrescope'. A potential clinical application of these microscope probes is their endoscopic use for optical biopsy of inner organs or guidance of conventional biopsy. As a mobile research tool they may permit imaging of neuronal activity in the brain of awake, behaving animals. Here, we review technological approaches to build miniaturized fluorescence microscopes and discuss their potential applications. [source] Tunable Guided-Mode Resonance Grating FilterADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Adriana Szeghalmi Abstract The optical characteristics of shallow 2D nanostructured polycarbonate samples are presented. Tunable guided-mode resonance filters are experimentally demonstrated for the visible spectral range when functional coatings are applied to 2D nanostructures by means of atomic layer deposition. The wavelength position of the reflection peaks can be easily tuned in a broad range (>150,nm) through rotation of the optical element around the axis normal to the substrate without changing the rest of the optical setup. Rigorous coupled wave approach simulation of model systems is performed to obtain insight into the complexity of the optical properties of these systems. The photonic nanostructures presented here are promising optics for application in ultra-compact, portable, miniaturized optical systems. [source] A Pumpless Methanol Feeding Method for Application in Direct Methanol Fuel Cell SystemsFUEL CELLS, Issue 4 2010J. Geng Abstract This paper presents a simple and reliable pumpless methanol feeding (PLMF) method for application in direct methanol fuel cell (DMFC) systems. The primary feature and advantage of the PLMF is as follows: it employs an approach that allows the cathode gas pressure to be connected with a fuel container for supplying the methanol fuel into the anode fuel loop, instead of using any feeding pump or other specially designed apparatuses. The PLMF has been used in a portable 25,W DMFC system and realised feeding methanol in real time for meeting the requirements of the system. The PLMF method not only is suitable for the DMFC system, but also can be used in other liquid-feeding fuel cell systems. [source] Sodium Borohydride Hydrolysis as Hydrogen Generator: Issues, State of the Art and Applicability Upstream from a Fuel CellFUEL CELLS, Issue 3 2010U. B. Demirci Abstract Today there is a consensus regarding the potential of NaBH4 as a good candidate for hydrogen storage and release via hydrolysis reaction, especially for mobile, portable and niche applications. However as gone through in the present paper two main issues, which are the most investigated throughout the open literature, still avoid NaBH4 to be competitive. The first one is water handling. The second one is the catalytic material used to accelerate the hydrolysis reaction. Both issues are objects of great attentions as it can be noticed throughout the open literature. This review presents and discusses the various strategies which were considered until now by many studies to manage water and to improve catalysts performances (reactivity and durability). Published studies show real improvements and much more efforts might lead to significant overhangs. Nevertheless, the results show that we are still far from envisaging short-term commercialisation. [source] Fluorimetric Nerve Gas Sensing Based on Pyrene Imines Incorporated into Films and Sub-Micrometer FibersADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Jeremy M. Rathfon Abstract The chemical sensing of nerve gas agents has become an increasingly important goal due to the 1995 terrorist attack in a Tokyo subway as well as national security concerns in regard to world affairs. Chemical detection needs to be sensitive and selective while being facile, portable, and timely. In this paper, a sensing approach using a pyrene imine molecule is presented that is fluorimetric in response. The detection of a chloro-Sarin surrogate is measured at 5 ppmv in less than 1 second and is highly selective towards halogenated organophosphates. The pyrene imine molecule is incorporated into polystyrene films as well as micrometer and sub-micrometer fibers. Using both a direct drawing approach and electrospinning, micrometer and nanofibers can be easily manufactured. Applications for functional sensing micrometer and nanofibers are envisioned for optical devices and photonics in addition to solution and airflow sensing devices. [source] Building a Compact, Low-Cost, and Portable Peristaltic Sampling PumpGROUND WATER, Issue 6 2007William W. Woessner Hydrogeologic research often involves obtaining water quality samples in field settings without vehicle access. Such conditions often require the use of a sampling pump. Researchers at The University of Montana have been using a handheld peristaltic pump powered by a rechargeable variable-speed drill. This Montana Drill Pump (MDP) is highly portable and can be inexpensively built for about $225 to $295 (US). Over the last two decades, the pump has been used to sample and filter (as appropriate) surface water and ground water for analyses of general inorganic and organic chemistry, stable and radioactive isotopes, pathogens, and trace pharmaceuticals and to develop small-diameter wells and sample suction lysimeters. The MDP provides researchers and educators with an economical tool to pump water in classrooms, laboratories, and field settings. [source] Carbon Nanotube/Hexa- peri -hexabenzocoronene Bilayers for Discrimination Between Nonpolar Volatile Organic Compounds of Cancer and Humid AtmospheresADVANCED MATERIALS, Issue 38 2010Yael Zilberman Cancer detection: The development of a cost-effective, portable and non-invasive diagnostic tool for detecting cancer from exhaled breath requires sensors that discriminate well between polar and nonpolar volatile organic compounds in highly humid atmospheres. Here we show that a chemiresistive bilayer comprised of a dense cap layer of discotic hexa-dodecyl-hexa-peri-hexabenzocoronene derivatives (hereby, HBC-C12) and a random network of carbon nanotubes (RN-CNT) as underlayer layer could fulfill these requirements. [source] A frontal solver for the 21st centuryINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 10 2006Jennifer A. Scott Abstract In recent years there have been a number of important developments in frontal algorithms for solving the large sparse linear systems of equations that arise from finite-element problems. We report on the design of a new fully portable and efficient frontal solver for large-scale real and complex unsymmetric linear systems from finite-element problems that incorporates these developments. The new package offers both a flexible reverse communication interface and a simple to use all-in-one interface, which is designed to make the package more accessible to new users. Other key features include automatic element ordering using a state-of-the-art hybrid multilevel spectral algorithm, minimal main memory requirements, the use of high-level BLAS, and facilities to allow the solver to be used as part of a parallel multiple front solver. The performance of the new solver, which is written in Fortran 95, is illustrated using a range of problems from practical applications. The solver is available as package HSL_MA42_ELEMENT within the HSL mathematical software library and, for element problems, supersedes the well-known MA42 package. Copyright © 2006 John Wiley & Sons, Ltd. [source] Anode-Supported Tubular Micro-Solid Oxide Fuel CellINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2 2007Partho Sarkar A tubular anode-supported "micro-solid oxide fuel cell" (,SOFC) has been developed for producing high volumetric power density (VPD) SOFC systems featuring rapid turn on/off capability. An electrophoretic deposition (EPD)-based, facile manufacturing process is being refined to produce the anode support, anode functional and electrolyte layers of a single cell. ,SOFCs (diameter <5 mm) have two main potential advantages, a substantial increase in the electrolyte surface area per unit volume of a stack and also rapid start-up. As fuel cell power is directly proportional to the active electrolyte surface area, a ,SOFC stack can substantially increase the VPD of an SOFC device. A decrease in tube diameter allows for a reduction in wall thickness without any degradation of a cell's mechanical properties. Owing to its thin wall, a ,SOFC has an extremely high thermal shock resistance and low thermal mass. These two characteristics are fundamental in reducing start-up and turn-off time for the SOFC stack. Traditionally, SOFC has not been considered for portable applications due to its high thermal mass and low thermal shock resistance (start-up time in hours), but with ,SOFCs' potential for rapid start-up, new possibilities for portable and transportable applications open up. [source] Fityk: a general-purpose peak fitting programJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5-1 2010Marcin Wojdyr Fityk is portable, open-source software for nonlinear curve fitting and data analysis. It specializes in fitting a sum of bell-shaped functions to experimental data. In particular, it enables Pawley refinement of powder diffraction data and size,strain analysis. [source] Real-time Visualization and Quantification of Retrograde Cardioplegia Delivery using Near Infrared Fluorescent ImagingJOURNAL OF CARDIAC SURGERY, Issue 6 2008Aravind T. Rangaraj M.D. Presently, there exist no established methods to quantitatively assess cardioplegia distribution intraoperatively and determine when retrograde cardioplegia is required. In this study, we evaluate the feasibility of near infrared (NIR) imaging for real-time visualization of cardioplegia distribution in a porcine model. Methods: A portable, intraoperative, real-time NIR imaging system was utilized. NIR fluorescent cardioplegia solution was developed by incorporating indocyanine green (ICG) into crystalloid cardioplegia solution. Real-time NIR imaging was performed while the fluorescent cardioplegia solution was infused via the retrograde route in five ex vivo normal porcine hearts and in five ex vivo porcine hearts status post left anterior descending (LAD) coronary artery ligation. Horizontal cross-sections of the hearts were obtained at proximal, middle, and distal LAD levels. Videodensitometry was performed to quantify distribution of fluorophore content. Results: The progressive distribution of cardioplegia was clearly visualized with NIR imaging. Complete visualization of retrograde distribution occurred within 4 minutes of infusion. Videodensitometry revealed retrograde cardioplegia, primarily distributed to the left ventricle (LV) and anterior septum. In hearts with LAD ligation, antegrade cardioplegia did not distribute to the anterior LV. This deficiency was compensated for with retrograde cardioplegia supplementation. Conclusions: Incorporation of ICG into cardioplegia allows real-time visualization of cardioplegia delivery via NIR imaging. This technology may prove useful in guiding intraoperative decisions pertaining to when retrograde cardioplegia is mandated. [source] Revised capillary suction time (CST) test to reduce consumable costs and improve dewaterability interpretationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2006Miklas Scholz Abstract The aim of this paper is to critically assess the standard capillary suction time (CST) test and to propose a modified device (prototype) and a revised CST procedure. The empirical CST test (using a circular funnel) is well established as the leading method for the determination of sludge dewaterability in spite of its current shortcomings such as restricted modelling possibilities, and therefore the ability to predict physical processes such as the amount of water bound by the paper. Nevertheless, the CST apparatus is portable, and the method is easy to conduct, quick, cost-effective and accurate, if the product of solid concentration and average specific resistance to filtration is of interest. A novel prototype with a rectangular instead of a circular funnel incorporating a stirrer (optional), and using a cheaper paper with similar or improved characteristics is proposed to reduce consumable costs and improve dewaterability interpretation. Copyright © 2005 Society of Chemical Industry [source] A force-field description of short-range repulsions for high density alkane molecular dynamics simulationsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 16 2004Joseph M. Hayes Abstract The use of Buckingham (exp-6) van der Waals potentials in molecular dynamics (MD) simulations can quite successfully reproduce experimental thermodynamic data at low densities. However, they are less successful in producing a description of the repulsive regions of the potential energy surface (PES) that is in accord with the results of high-level ab initio computations. We show that Morse potentials can be parameterized to give excellent fits to both the attractive and repulsive regions of the PES. The best set of alkane van der Waals Morse function parameters reported to date for the description of nonbond repulsive interactions is presented, as determined by comparison with both ab initio and experimental results. C,C, H,H and C,H atom-pair potentials employing parameter sets based on the use of the geometric mean in the fitting procedure are found to be portable from methane to n- butane. Fitting to a combination of methane dimer interaction energies and forces from ab initio calculations yields parameter sets whose performance is superior to those determined from the interaction energies alone. Used in MD simulations, our newly developed parameter sets predict thermodynamic functions that show better agreement with experiment than those based on parameter sets in common use. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1953,1966, 2004 [source] Novel computer program for fast exact calculation of accessible and molecular surface areas and average surface curvatureJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 6 2002Oleg V. Tsodikov Abstract New computer programs, SurfRace and FastSurf, perform fast calculations of the solvent accessible and molecular (solvent excluded) surface areas of macromolecules. Program SurfRace also calculates the areas of cavities inaccessible from the outside. We introduce the definition of average curvature of molecular surface and calculate average molecular surface curvatures for each atom in a structure. All surface area and curvature calculations are analytic and therefore yield exact values of these quantities. High calculation speed of this software is achieved primarily by avoiding computationally expensive mathematical procedures wherever possible and by efficient handling of surface data structures. The programs are written initially in the language C for PCs running Windows 2000/98/NT, but their code is portable to other platforms with only minor changes in input-output procedures. The algorithm is robust and does not ignore either multiplicity or degeneracy of atomic overlaps. Fast, memory-efficient and robust execution make this software attractive for applications both in computationally expensive energy minimization algorithms, such as docking or molecular dynamics simulations, and in stand-alone surface area and curvature calculations. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 600,609, 2002 [source] Selective Detection of Trace Nitroaromatic, Nitramine, and Nitrate Ester Explosive Residues Using a Three-Step Fluorimetric Sensing Process: A Tandem Turn-off, Turn-on Sensor,JOURNAL OF FORENSIC SCIENCES, Issue 6 2007Jason C. Sanchez M.S. Abstract:, Detection of trace quantities of explosive residues plays a key role in military, civilian, and counter-terrorism applications. To advance explosives sensor technology, current methods will need to become cheaper and portable while maintaining sensitivity and selectivity. The detection of common explosives including trinitrotoluene (TNT), cyclotrimethylenetrinitramine, cyclotetramethylene-tetranitramine, pentaerythritol tetranitrate, 2,4,6-trinitrophenyl-N-methylnitramine, and trinitroglycerin may be carried out using a three-step process combining "turn-off" and "turn-on" fluorimetric sensing. This process first detects nitroaromatic explosives by their quenching of green luminescence of polymetalloles (,em , 400,510 nm). The second step places down a thin film of 2,3-diaminonaphthalene (DAN) while "erasing" the polymetallole luminescence. The final step completes the reaction of the nitramines and/or nitrate esters with DAN resulting in the formation of a blue luminescent traizole complex (,em = 450 nm) providing a "turn-on" response for nitramine and nitrate ester-based explosives. Detection limits as low as 2 ng are observed. Solid-state detection of production line explosives demonstrates the applicability of this method to real world situations. This method offers a sensitive and selective detection process for a diverse group of the most common high explosives used in military and terrorist applications today. [source] Gastric motility and autonomic activity during obstructive sleep apneaALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2006M. URATA Summary Background Patients with Obstructive Sleep Apnea Syndrome (OSAS) often experience gastroesophageal reflux disease (GERD). Aim To investigate gastric motility and autonomic nervous activity during sleep apnea. Methods The subjects of this study were 20 individuals with OSAS who experienced 10 or more sleep apnoea events per hour, as measured with a portable sleep polygraph. A percutaneous electrogastrography (EGG) and fast Fourier transformation analysis was carried out on the results. The mean amplitude was compared for bradygastria, normogastria and tachygastria. Spectral analysis of heart rate variability was performed, and low-frequency (LF) power, high-frequency (HF) power and the LF/HF ratio were measured. Oesophagogastroduodenal endoscopy was performed on each subject, and the presence of reflux oesophagitis (RE) was diagnosed according to the Los Angeles (LA) grade classification. Moreover, questionnaire for the diagnosis of reflux disease (QUEST) was carried out. Results Normogastria was significantly decreased, and brady-, tachygastria, or both were increased during sleep apnea (P < 0.01). There was no significant relation between LA grade classification of RE and severity of OSAS. The LF/HF ratio was significantly higher during sleep apnea for patients with RE and OSAS, but the opposite for those with RE without OSAS. Decreased percutaneous arterial oxygen saturation and normogastria were independent risk factors for the severity of RE. Conclusions The present study suggested that, in addition to decreased pressure on the pleural cavity, factors affecting the development of RE might include abnormal gastric motility, low oxygen, and increased sympathetic nervous activity during sleep apnea. [source] A broadband, circular switched parasitic array for portable and vehicular mobile DVB-T applications at the V UHF bandMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2008Stylianos C. Panagiotou Abstract A broadband, circular switched parasitic array with two active elements, suitable for DVB-T applications at the V-UHF band is designed with the aid of a genetic algorithm. Numerical as well as measurements results are presented for a single switch position. Simulation results are also presented for switched-beam array operation, using the measured antenna radiation patterns. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1727,1732, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23494 [source] | |||||||||||||||||||||||||||||||||||||