1,582 research outputs found

    Fast Grasp Contact Computation for a Serial Robot

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    A system includes a controller and a serial robot having links that are interconnected by a joint, wherein the robot can grasp a three-dimensional (3D) object in response to a commanded grasp pose. The controller receives input information, including the commanded grasp pose, a first set of information describing the kinematics of the robot, and a second set of information describing the position of the object to be grasped. The controller also calculates, in a two-dimensional (2D) plane, a set of contact points between the serial robot and a surface of the 3D object needed for the serial robot to achieve the commanded grasp pose. A required joint angle is then calculated in the 2D plane between the pair of links using the set of contact points. A control action is then executed with respect to the motion of the serial robot using the required joint angle

    Blast injuries in children: a mixed-methods narrative review.

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    Background and significance. Blast injuries arising from high explosive weaponry is common in conflict areas. While blast injury characteristics are well recognised in the adults, there is a lack of consensus as to whether these characteristics translate to the paediatric population. Understanding blast injury patterns in this cohort is essential for providing appropriate provision of services and care for this vulnerable cohort. Methods. In this mixed-method review, original papers were screened for data pertaining to paediatric injuries following blasts. Information on demographics, morbidity and mortality and service requirements were evaluated. The papers were written and published in English from a range of international specialists in the field. Patient and public involvement statement: No patients or members of the public were involved in this review. Results. Children affected by blast injuries are predominantly male and their injuries arise from explosive remnants of war, particularly unexploded ordinance. Blasts show increased morbidity and mortality in younger children, while older children have injury patterns similar to adults. Head and burn injuries represent a significant cause of mortality in young children, while lower limb morbidity is reduced compared to adults. Children have a disproportionate requirement for both operative and non-operative service resources, and provisions for this burden are essential. Conclusions. Certain characteristics of paediatric injuries arising from blasts are distinct from that of the adult cohort, while the intensive demands on services highlights the importance of understanding the diverse injury patterns in order to optimise future service provisions in caring for this the child blast survivor

    THz spectroscopy of the atmosphere for climatology and meteorology applications

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    We present a new satellite-based instrument concept that will enable global measurements of atmospheric temperature and humidity profiles with unprecedented resolution and accuracy, compared to currently planned missions. It will also provide global measurements of essential climate variables related to ice clouds that will better constrain global climate models. The instrument is enabled by the use of superconducting detectors coupled to superconducting filterbank spectrometers, operating between 50GHz and 850 GHz. We present the science drivers, the current instrument concept and status, and predicted performance

    A Chandra X-ray Study of Cygnus A - II. The Nucleus

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    We report Chandra ACIS and quasi-simultaneous RXTE observations of the nearby, powerful radio galaxy Cygnus A, with the present paper focusing on the properties of the active nucleus. In the Chandra observation, the hard (> a few keV) X-ray emission is spatially unresolved with a size \approxlt 1 arcsec (1.5 kpc, H_0 = 50 km s^-1 Mpc^-1) and coincides with the radio and near infrared nuclei. In contrast, the soft (< 2 keV) emission exhibits a bi-polar nebulosity that aligns with the optical bi-polar continuum and emission-line structures and approximately with the radio jet. In particular, the soft X-ray emission corresponds very well with the [O III] \lambda 5007 and H\alpha + [N II] \lambda\lambda 6548, 6583 nebulosity imaged with HST. At the location of the nucleus there is only weak soft X-ray emission, an effect that may be intrinsic or result from a dust lane that crosses the nucleus perpendicular to the source axis. The spectra of the various X-ray components have been obtained by simultaneous fits to the 6 detectors. The compact nucleus is detected to 100 keV and is well described by a heavily absorbed power law spectrum with \Gamma_h = 1.52^{+0.12}_{-0.12} (similar to other narrow line radio galaxies) and equivalent hydrogen column N_H (nuc) = 2.0^{+0.1}_{-0.2} \times 10^{23} cm^-2. (Abstract truncated).Comment: To be published in the Astrophysical Journal, v564 January 1, 2002 issue; 34 pages, 11 figures (1 color

    Vascular Endothelial Growth Factor-A Gene Electrotransfer Promotes Angiogenesis in a Porcine Model of Cardiac Ischemia

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    This study aimed to assess safety and therapeutic potential of gene electrotransfer (GET) as a method for delivery of plasmid encoding vascular endothelial growth factor A (VEGF-A) to ischemic myocardium in a porcine model. Myocardial ischemia was induced by surgically occluding the left anterior descending coronary artery in swine. GET following plasmid encoding VEGF-A injection was performed at four sites in the ischemic region. Control groups either received injections of the plasmid without electrotransfer or injections of the saline vehicle. Animals were monitored for 7 weeks and the hearts were evaluated for angiogenesis, myocardial infarct size and left ventricular contractility. Arteriograms suggest growth of new arteries as early as 2 weeks after treatment in electrotransfer animals. There is a significant reduction of infarct area and left ventricular contractility is improved in GET-treated group compared with controls. There was no significant difference in mortality of animals treated with GET of plasmid encoding VEGF-A from the control groups. Gene delivery of plasmid encoding VEGF-A to ischemic myocardium in a porcine model can be accomplished safely with potential for myocardial repair and regeneration

    First characterization of a superconducting filter-bank spectrometer for hyper-spectral microwave atmospheric sounding with transition edge sensor readout

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    We describe the design, fabrication, integration and characterization of a prototype superconducting filter bank with transition edge sensor readout designed to explore millimetre-wave detection at frequencies in the range 40 to 65 GHz. Results indicate highly uniform filter channel placement in frequency and high overall detection efficiency. The route to a full atmospheric sounding instrument in this frequency range is discussed.Centre for Earth Observing Instrumentation UK (CEOI

    Crankcase sampling of PM from a fired and motored compression ignition engine

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    Crankcase emissions are a complex mixture of combustion products and aerosol generated from lubrication oil. The crankcase emissions contribute substantially to the total particulate matter (PM) emitted from an engine. Environment legislation demands that either the combustion and crankcase emissions are combined to give a total measurement, or the crankcase gases are re-circulated back into the engine. There is a lack of understanding regarding the physical processes that generate crankcase aerosols, with a paucity of information on the size/mass concentrations of particles present in the crankcase. In this study the particulate matter crankcase emissions were measured from a fired and motored 4 cylinder compression ignition engine at a range of speeds and crankcase locations. A sequence of sampling equipment was used to characterise the emissions in the size range 5 nm - 19 μm; Cambustion DMS500 fast particulate spectrometer, TSI Scanning Mobility Particle Sizer (SMPS), TSI™ Condensation Particle Counter (CPC) and, TSI™ Aerodynamic Particle Sizer (APS). The combination of the two test engines and range of sampling equipment provided new information on the generation and behavior of aerodynamic particulate matter within an engine crankcase. Data is presented for the effect of controlled parameter changes on number distributions over the measured particle size range. A complex lognormal bimodal size distribution of sub micron accumulation mode particles was present in the crankcase of both engines at a low idle speed of 900rpm. At 1400rpm this complex distribution was not present. Increasing the engine load, on the fired engine, initially reduced the particle number concentration with a final significant increase in particle number concentration at 75% load. At 900 rpm 50% load there was a single strong peak at 32nm in the rocker cover however sampling from the push rod gallery and sump showed a strongly bimodal distribution with peaks at 32nm and 133nm. All other sampling data, from the fired engine, was consistent at each sampling location. The SMPS results, 15-665nm, on the motored engine showed location dependency, with the highest number concentration of particles present in the push rod gallery

    3,4-Methylenedioxymethamphetamine Activates Nuclear Factor- κB, Increases Intracellular Calcium, and Modulates Gene Transcription in Rat Heart Cells

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    3,4-Methylenedioxymethamphetamine (MDMA) is an illicit psychoactive drug that has gained immense popularity among teenagers and young adults. The cardiovascular toxicological consequences of abusing this compound have not been fully characterized. The present study utilized a transient transfection/dual luciferase genetic reporter assay, fluorescence confocal microscopy, and gene expression macroarray technology to determine nuclear factor-κB (NF-κB) activity, intracellular calcium balance, mitochondrial depolarization, and gene transcription profiles, respectively, in cultured rat striated cardiac myocytes (H9c2) exposed to MDMA. At concentrations of 1×10−3 M and 1×10−2 M, MDMA significantly enhanced NF-κB reporter activity compared with 0 M (medium only) control. This response was mitigated by cotransfection with IκB for 1×10−3 M but not 1×10−2 M MDMA. MDMA significantly increased intracellular calcium at concentrations of 1×10−3 M and 1×10−2 M and caused mitochondrial depolarization at 1×10−2 M. MDMA increased the transcription of genes that are considered to be biomarkers in cardiovascular disease and genes that respond to toxic indults. Selected gene activation was verified via temperature-gradient RT-PCR conducted with annealing temperatures ranging from 50°C to 65°C. Collectively, these results suggest that MDMA may be toxic to the heart through its ability to activate the myocardial NF-κB response, disrupt cytosolic calcium and mitochondrial homeostasis, and alter gene transcription
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