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Technique Capable (technique + capable)
Selected AbstractsInteractive Global Photon MappingCOMPUTER GRAPHICS FORUM, Issue 4 2009B. Fabianowski Abstract We present a photon mapping technique capable of computing high quality global illumination at interactive frame rates. By extending the concept of photon differentials to efficiently handle diffuse reflections, we generate footprints at all photon hit points. These enable illumination reconstruction by density estimation with variable kernel bandwidths without having to locate the k nearest photon hits first. Adapting an efficient BVH construction process for ray tracing acceleration, we build photon maps that enable the fast retrieval of all hits relevant to a shading point. We present a heuristic that automatically tunes the BVH build's termination criterion to the scene and illumination conditions. As all stages of the algorithm are highly parallelizable, we demonstrate an implementation using NVidia's CUDA manycore architecture running at interactive rates on a single GPU. Both light source and camera may be freely moved with global illumination fully recalculated in each frame. [source] Novel coupling Rosenbrock-based algorithms for real-time dynamic substructure testingEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 3 2008O. S. Bursi Abstract Real-time testing with dynamic substructuring is a novel experimental technique capable of assessing the behaviour of structures subjected to dynamic loadings including earthquakes. The technique involves recreating the dynamics of the entire structure by combining an experimental test piece consisting of part of the structure with a numerical model simulating the remainder of the structure. These substructures interact in real time to emulate the behaviour of the entire structure. Time integration is the most versatile method for analysing the general case of linear and non-linear semi-discretized equations of motion. In this paper we propose for substructure testing, L-stable real-time (LSRT) compatible integrators with two and three stages derived from the Rosenbrock methods. These algorithms are unconditionally stable for uncoupled problems and entail a moderate computational cost for real-time performance. They can also effectively deal with stiff problems, i.e. complex emulated structures for which solutions can change on a time scale that is very short compared with the interval of time integration, but where the solution of interest changes on a much longer time scale. Stability conditions of the coupled substructures are analysed by means of the zero-stability approach, and the accuracy of the novel algorithms in the coupled case is assessed in both the unforced and forced conditions. LSRT algorithms are shown to be more competitive than popular Runge,Kutta methods in terms of stability, accuracy and ease of implementation. Numerical simulations and real-time substructure tests are used to demonstrate the favourable properties of the proposed algorithms. Copyright © 2007 John Wiley & Sons, Ltd. [source] Intravascular neural interface with nanowire electrodeELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 7 2009Hirobumi Watanabe Abstract A minimally invasive electrical recording and stimulating technique capable of simultaneously monitoring the activity of a significant number (e.g., 103 to 104) of neurons is an absolute prerequisite in developing an effective brain,machine interface. Although there are many excellent methodologies for recording single or multiple neurons, there has been no methodology for accessing large numbers of cells in a behaving experimental animal or human individual. Brain vascular parenchyma is a promising candidate for addressing this problem. It has been proposed [1, 2] that a multitude of nanowire electrodes introduced into the central nervous system through the vascular system to address any brain area may be a possible solution. In this study we implement a design for such microcatheter for ex vivo experiments. Using Wollaston platinum wire, we design a submicron-scale electrode and develop a fabrication method. We then evaluate the mechanical properties of the electrode in a flow when passing through the intricacies of the capillary bed in ex vivo Xenopus laevis experiments. Furthermore, we demonstrate the feasibility of intravascular recording in the spinal cord of Xenopus laevis. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(7): 29,37, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10058 [source] Raman spectroscopy and molecular simulation investigations of adsorption on the surface of single-walled carbon nanotubes and nanospheresJOURNAL OF RAMAN SPECTROSCOPY, Issue 6 2007Maher S. Amer Abstract Raman spectroscopy has, for long, been utilized to investigate material systems on the micro and mesoscales. Recently, the technique has proven its ability in exploring systems on the nanoscale. In this paper, we review our recent work on the Raman investigation of molecular adsorption from liquid mixtures on surfaces of single-walled carbon nanotubes and fullerene nanospheres, emphasizing the following major research findings: the development of a Raman-based technique capable of sensing local chemical interactions on the surface of carbon nanotubes and spheres; the molecular simulation results supporting the Raman investigation; the possibility of creating mesostructures based upon mixtures of carbon nanotubes and nanospheres that are crucial for selective adsorption. The current findings represent a major new thrust for the development of new nanostructured materials with superior adsorption capabilities and unique applications. Copyright © 2007 John Wiley & Sons, Ltd. [source] A high-throughput determination of metal concentrations in whole intact Arabidopsis thaliana seeds using synchrotron-based X-ray fluorescence spectroscopyJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2006Lester W. Young The identification of genes involved in metal metabolism in plants requires the `screening' of thousands of genetic variants. While inductively coupled plasma mass-spectroscopy has been used to identify variants with an altered total metal concentration, a more convenient high-throughput technique capable of examining individual seeds (or other tissues) would be useful. Here, the high brightness of synchrotron radiation has been utilised to examine relative metal concentrations in seeds of the genetically well characterised plant Arabidopsis thaliana. The relative concentrations of Mn, Fe, Ni, Cu and Zn in individual seeds were determined using a 500,µm × 500,µm beam. Metal concentrations were normally distributed, except where metal-containing dust contaminated the samples. Neither seed orientation nor genetic background (from three `wild type' variants with different genetic lineages) had a significant affect on the Zn-normalised metal concentration. No advantages, such as the observation of tissue-specific metal accumulation, were obtained by using a 50,µm × 50,µm beam. A high-throughput proof-of-concept experiment was demonstrated that could be used to screen libraries of genetic variants for individuals with altered metal concentrations. Further work is required to standardise the technique before screening of libraries is possible. [source] Application of ultrasound and neural networks in the determination of filler dispersion during polymer extrusion processesPOLYMER ENGINEERING & SCIENCE, Issue 6 2005Zhigang Sun Mineral filler dispersion is important information for the production of mineral-charged polymers. In order to achieve timely control of product quality, a technique capable of providing real-time information on filler dispersion is highly desirable. In this work, ultrasound, temperature, and pressure sensors as well as an amperemeter of the extruder motor drive were used to monitor the extrusion of mineral-filled polymers under various experimental conditions in terms of filler type, filler concentration, feeding rate, screw rotation speed, and barrel temperature. Then, neural network relationships were established among the filler dispersion index and three categories of variables, namely, control variables of the extruder, extruder-dependent measured variables, and extruder-independent measured variables (based on ultrasonic measurement). Of the three categories of variables, the process control variables and extruder-independent ultrasonically measured variables performed best in inferring the dispersion index through a neural network model. While the neural network model based on control variables could help determine the optimal experimental conditions to achieve a dispersion index, the extruder-independent network model based on ultrasonic measurement is suitable for in-line measurement of the quality of dispersion. This study has demonstrated the feasibility of using ultrasound and neural networks for in-line monitoring of dispersion during extrusion processes of mineral-charged polymers. POLYM. ENG. SCI., 45:764,772, 2005. © 2005 Society of Plastics Engineers [source] FPRL-1 induces modifications of migration-associated proteins in human neutrophilsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 17 2006Karsten Boldt Abstract Human polymorphonuclear neutrophils (PMNs) are an important cell population of the innate immune system, which migrates following concentration gradients of chemokines or chemoattractants to locations of infection and inflammation in order to eliminate invading microorganisms and cell debris. For both migration and adhesion of PMNs to various tissues, the dynamic remodeling of the cytoskeleton is key prerequisite. In this context, the formyl peptide receptor-like,1 (FPRL-1) is an important chemoattractant receptor expressed on PMNs. In this study, we show that a short stimulation of FPRL-1 with either a synthetic peptide ligand (W-peptide) or a natural ligand (sCK,8-1) changes the protein pattern of PMNs as assessed by 2-D-DIGE. MS analysis of selected deregulated protein species resulted in the identification of proteins that are involved in the remodeling process of the actin- and tubulin-based cytoskeleton, such as L -plastin, moesin, cofilin, and stathmin. Subsequent validation experiments performed either by Western blotting or phosphoprotein-specific gel staining (Pro-Q Diamond) revealed that L -plastin is phosphorylated, whereas moesin, cofilin, and stathmin are dephosphorylated in PMNs upon FPRL-1 stimulation. These findings suggest that FPRL-1 signaling targets proteins that regulate the motility of PMNs and moreover show that 2-D-DIGE is a technique capable of detecting and quantifying differently modified (e.g., phosphorylated) protein variants. [source] Interference of chlorofluorocarbon (CFC)-containing inhalers with measurements of volatile compounds using selected ion flow tube mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 3 2009Michael J. Epton Selected ion flow tube mass spectrometry (SIFT-MS) is a sensitive technique capable of measuring volatile compounds (VCs) in complex gas mixtures in real time; it is now being applied to breath analysis. We investigated the effect of inhalers containing chlorofluorocarbons (CFCs) on the detection and measurement of haloamines in human breath. SIFT-MS mass scans (MS) and selected ion monitoring (SIM) scans were performed on three healthy non-smoking volunteers before and after inhalation of the following medications: CombiventÔ metered-dose inhaler (MDI) (CFC-containing); VentolinÔ MDI (CFC-free); AtroventÔ MDI (CFC-free), BeclazoneÔ MDI (CFC-containing); DuolinÔ nebuliser. In addition, the duration of the persistence of the mass/charge ratios was measured for 20,h. Inhalers containing CFCs generated large peaks at m/z 85, 87, 101, 103 and 105 in vitro and in vivo, consistent with the predicted product ions of CFCs 12, 114 and 11. No such peaks were seen with DuolinÔ via nebuliser, or CFC-free MDIs. We conclude that measurement of VCs, such as haloamines, with product ions of similar m/z values to the ions found for CFCs would be significantly affected by the presence of CFCs in inhalers. This issue needs to be accounted for prior to the measurement of VCs in breath in people using inhalers containing CFCs. Copyright © 2009 John Wiley & Sons, Ltd. [source] White matter abnormalities in bipolar disorder: a voxel-based diffusion tensor imaging studyBIPOLAR DISORDERS, Issue 4 2008Stefania Bruno Objectives:, In bipolar disorder (BD), dysregulation of mood may result from white matter abnormalities that disrupt fronto-subcortical circuits. In this study, we explore such abnormalities using diffusion tensor imaging (DTI), an imaging technique capable of detecting subtle changes not visible with conventional magnetic resonance imaging (MRI), and voxel-based analysis. Methods:, Thirty-six patients with BD, all but two receiving antidepressants or mood stabilizers, and 28 healthy controls matched for age and gender were studied. Diffusion-weighted echoplanar images (DW-EPI) were obtained using a 1.5T scanner. Voxel-based analysis was performed using SPM 2. Differences between the groups in mean diffusivity and fractional anisotropy (FA) were explored. Results:, In the patient group, mean diffusivity was increased in the right posterior frontal and bilateral prefrontal white matter, while FA was increased in the inferior, middle temporal and middle occipital regions. The areas of increased mean diffusivity overlapped with those previously found to be abnormal using volumetric MRI and magnetization transfer imaging (MTI) in the same group of patients. Conclusions:, White matter abnormalities, predominantly in the fronto-temporal regions, can be detected in patients with BD using DTI. The neuropathology of these abnormalities is uncertain, but neuronal and axonal loss, myelin abnormalities and alterations in axonal packing density are likely to be relevant. The neuroprotective effects of some antidepressants and mood stabilizers make it unlikely that medication effects could explain the abnormalities described here, although minor effects cannot be excluded. [source] | |||||||||||||