An Automated Measurement of Image Slice Thickness of Computed Tomography

Measurement of the slice thickness in computed tomography (CT) is usually made using a special phantom, such as the AAPM CT performance phantom. Images of the phantom are analyzed manually and subjectively. The purpose of this study is to develop an automated system for measuring the slice thickness of the CT image of the phantom using MATLAB software.The CT AAPM performance phantom was scanned by a 128 multi-slice computed tomography scanner (Revolution Evo, GE Healthcare, Waukesha, WI) at a slice thickness of 5 mm with four different phantom orientations and also scanned by a 6 multi-slice CT scanner (Somatom Emotion 6, Siemens AG, Forchheim, Germany) for two slice thicknesses of 5 and 10 mm. Our automatedmethod produced an accurateslice thickness value less than 0.5 mm different from the nominal slice thicknesses and manual measurements. Similar results were obtained when the phantom was rotated. This system is more objective and effective compared to manual systems

Titan's magnetic field signature during the Cassini T34 flyby: Comparison between hybrid simulations and MAG data

During the T34 flyby on 19 July 2007, the Cassini spacecraft passed through the magnetic pile-up region at Titan's ramside. The magnetic environment of Titan during this flyby is studied using a three-dimensional hybrid simulation model. This approach treats the electrons of the plasma as a massless, charge-neutralizing fluid, whereas the effects of finite ion gyroradii are taken into account by modeling the ions as individual particles. The simulation results are compared to data collected by the Cassini Magnetometer Instrument. The key features of the measured magnetic field signature have shown to be fully reproducible in the framework of the simulation model. Several signatures in the observed magnetic field can be ascribed to the passage of the Cassini spacecraft through the magnetic barrier upstream of Titan.Fil: Simon, S.. Technische Universitat Braunschweig; AlemaniaFil: Motschmann, U.. Technische Universitat Braunschweig; AlemaniaFil: Kleindienst, G.. Technische Universitat Braunschweig; AlemaniaFil: Glassmeier, K. H.. Technische Universitat Braunschweig; AlemaniaFil: Bertucci, Cesar. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Dougherty, M. K.. Imperial College London; Reino Unid

Feasibility of Photofrin II as a radiosensitizing agent in solid tumors - Preliminary results

Background: Photofrin II has been demonstrated to serve as a specific and selective radiosensitizing agent in in vitro and in vivo tumor models. We aimed to investigate the feasibility of a clinical application of Photofrin II. Material and Methods: 12 patients were included in the study (7 unresectable solid tumors of the pelvic region, 3 malignant gliomas, 1 recurrent oropharyngeal cancer, 1 recurrent adenocarcinoma of the sphenoid sinus). The dose of ionizing irradiation was 30-50.4 Gy; a boost irradiation of 14 Gy was added for the pelvic region. All patients were intravenously injected with 1 mg/kg Photofrin II 24 h prior to the commencement of radiotherapy. Magnetic resonance imaging (MRI) controls and in some cases positron emission tomography (PET) were performed in short intervals. The mean follow-up was 12.9 months. Results: No major adverse events were noted. Minor adverse events consisted of mild diarrhea, nausea and skin reactions. A complete remission was observed in 4/12 patients. A reduction in local tumor volume of > 45% was achieved in 4/12 patients. Stable disease was observed in 4/12 patients. 1 patient showed local disease progression after 5 months. Conclusion: The early follow-up results are encouraging regarding the feasibility of the application of Photofrin II as a radiosensitizing agent

An intelligent assistant for exploratory data analysis

In this paper we present an account of the main features of SNOUT, an intelligent assistant for exploratory data analysis (EDA) of social science survey data that incorporates a range of data mining techniques. EDA has much in common with existing data mining techniques: its main objective is to help an investigator reach an understanding of the important relationships ina data set rather than simply develop predictive models for selectd variables. Brief descriptions of a number of novel techniques developed for use in SNOUT are presented. These include heuristic variable level inference and classification, automatic category formation, the use of similarity trees to identify groups of related variables, interactive decision tree construction and model selection using a genetic algorithm

On the nature of the X-ray source in GK Per

We report XMM-Newton observations of the intermediate polar (IP) GK Per on the rise to the 2002 outburst and compare them to Chandra observations during quiescence. We find an asymmetric spin light curve implying an asymmetric shape of a semi-transparent accretion curtain. A low Fe xvii (15.01/15.26 A) line flux ratio confirms the need for an asymmetric geometry and significant effects of resonant line scattering. Medium resolution spectra in outburst and quiescence are both fitted with a leaky absorber model for the post shock hard X-ray emission, a black body (outburst) for the thermalized X-ray emission from the white dwarf and an optically thin spectrum. The difference between high and low spin as well as QPO/flares states can be explained by a variation in the absorbing column density. The Fe fluorescence at 6.4 keV (equivalent width of 447 eV) is not significantly variable during spin cycle or on QPO periods. High-resolution RGS spectra reveal a number of emission lines from H-like and He-like elements. The lines are broader than the instrumental response with a roughly constant velocity dispersion for different lines, indicating identical origin. He-like emission lines are used to give values for the electron densities of log n_e ~ 12. We do not detect any variation in the emission lines during the spin cycle, implying that the lines are not noticeably obscured or absorbed. We conclude that they originate in the accretion curtains and propose a model for their shape.Comment: 14 pages, 22 figures, accepted by A&A; text re quiescent data changed slightly, references adde

The large-scale ionised outflow of CH Cygni

HST and ground-based [OII} and [NII] images obtained from 1996 to 1999 reveal the existence of a ionised optical nebula around the symbiotic binary CH Cyg extending out to 5000 A.U. from the central stars. The observed velocity range of the nebula, derived from long-slit echelle spectra, is of 130 km/s. In spite of its complex appearence, the velocity data show that the basic morphology of the inner regions of the optical nebula is that of a bipolar (or conical) outflow extending nearly along the plane of the sky out to some 2000 A.U. from the centre. Even if the extension of this bipolar outflow and its position angle are consistent with those of the radio jet produced in 1984 (extrapolated to the time of our optical imagery), no obvious counterpart is visible of the original, dense radio bullets ejected by the system. We speculate that the optical bipolar outflow might be the remannt of the interaction of the bullets with a relatively dense circumstellar medium.Comment: 8 text pages + 3 figures (jpeg). ApJ in press. For a full PostScript version with figures inline see ftp://ftp.ll.iac.es/pub/research/preprints/PP252001.ps.g

Formalization of Transform Methods using HOL Light

Transform methods, like Laplace and Fourier, are frequently used for analyzing the dynamical behaviour of engineering and physical systems, based on their transfer function, and frequency response or the solutions of their corresponding differential equations. In this paper, we present an ongoing project, which focuses on the higher-order logic formalization of transform methods using HOL Light theorem prover. In particular, we present the motivation of the formalization, which is followed by the related work. Next, we present the task completed so far while highlighting some of the challenges faced during the formalization. Finally, we present a roadmap to achieve our objectives, the current status and the future goals for this project.Comment: 15 Pages, CICM 201

Lambda and Antilambda polarization from deep inelastic muon scattering

We report results of the first measurements of Lambda and Antilambda polarization produced in deep inelastic polarized muon scattering on the nucleon. The results are consistent with an expected trend towards positive polarization with increasing x_F. The polarizations of Lambda and Antilambda appear to have opposite signs. A large negative polarization for Lambda at low positive x_F is observed and is not explained by existing models.A possible interpretation is presented.Comment: 9 pages, 2 figure

Gamma interferon induces different keratinocyte cellular patterns of expression of HLA-DR and DQ and intercellular adhesion molecule-I (ICAM-I) antigens

With indirect immunofluorescence techniques we demonstrated that recombinant gamma-interferon induced the expression of the class II antigens HLA-DR and HLA-DQ as well as intercellular adhesion molecule-1 (ICAM-1) on normal, cultured human keratinocytes grown in low-calcium, serum-free medium. Each antigen displayed a distinctive cellular staining pattern. HLA-DR was strongly localized to perinuclear zones with intense cell surface expression; HLA-DQ displayed a perinuclear accentuation, but with minimal cell surface staining, and ICAM-1 was strongly expressed in a diffuse cytoplasmic pattern with intense cell surface expression. Keratinocytes grown in medium supplemented with 10% fetal calf serum underwent differentiation, with a diminished expression of all three antigens as compared to those grown in low-calcium, serum-free medium. These results confirm that gamma interferon can differentially regulate HLA-DR nd HLA-DQ expression; that there are probably different biochemical metabolic pathways by which these three molecules are expressed on keratinocytes, and that the expression is also a function of the degree of keratinocyte differentiation. The strong cell surface expression of ICAM-1 is suggested to be of major importance as the recognition molecule, by which T cells bind to gamma interferon exposed keratinocytes, and suggests and integral role for this molecule in epidermal lymphocyte trafficking.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74686/1/j.1365-2133.1989.tb07759.x.pd