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Sample records for aberration corrected scanning

  1. Correction of surface aberration in strain scanning method with analyzer

    International Nuclear Information System (INIS)

    Shobu, Takahisa; Mizuki, Junichiro; Suzuki, Kenji; Akiniwa, Yoshiaki; Tanaka, Keisuke

    2006-01-01

    When a gauge volume sank below a specimen surface, the diffraction angle shifts. Thus, it is required to correct the surface aberration. For the annealed specimen of S45C, the shift in the diffraction angle was investigated using a strain scanning method with Ge (111) analyzer. This phenomenon was caused by the difference in the centroid between the geometric and the instrumental gauge volumes. This difference is explained by the following factors; 1) the change in the gauge volume by the divergence of the analyzer, 2) the X-ray penetration depth, 3) the gap of the centre line between the double receiving slits due to mis-setting the analyzer. As a result, the correcting method considered into these factors was proposed. For the shot-peened specimens of S45C, the diffraction angles were measured and corrected by our method. The distribution of the residual stress agreed with that obtained by the removal method. (author)

  2. Three-dimensional optical transfer functions in the aberration-corrected scanning transmission electron microscope.

    Science.gov (United States)

    Jones, L; Nellist, P D

    2014-05-01

    In the scanning transmission electron microscope, hardware aberration correctors can now correct for the positive spherical aberration of round electron lenses. These correctors make use of nonround optics such as hexapoles or octupoles, leading to the limiting aberrations often being of a nonround type. Here we explore the effect of a number of potential limiting aberrations on the imaging performance of the scanning transmission electron microscope through their resulting optical transfer functions. In particular, the response of the optical transfer function to changes in defocus are examined, given that this is the final aberration to be tuned just before image acquisition. The resulting three-dimensional optical transfer functions also allow an assessment of the performance of a system for focal-series experiments or optical sectioning applications. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  3. Spherical aberration correction in a scanning transmission electron microscope using a sculpted thin film.

    Science.gov (United States)

    Shiloh, Roy; Remez, Roei; Lu, Peng-Han; Jin, Lei; Lereah, Yossi; Tavabi, Amir H; Dunin-Borkowski, Rafal E; Arie, Ady

    2018-03-27

    Nearly eighty years ago, Scherzer showed that rotationally symmetric, charge-free, static electron lenses are limited by an unavoidable, positive spherical aberration. Following a long struggle, a major breakthrough in the spatial resolution of electron microscopes was reached two decades ago by abandoning the first of these conditions, with the successful development of multipole aberration correctors. Here, we use a refractive silicon nitride thin film to tackle the second of Scherzer's constraints and demonstrate an alternative method for correcting spherical aberration in a scanning transmission electron microscope. We reveal features in Si and Cu samples that cannot be resolved in an uncorrected microscope. Our thin film corrector can be implemented as an immediate low cost upgrade to existing electron microscopes without re-engineering of the electron column or complicated operation protocols and can be extended to the correction of additional aberrations. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Non-common path aberration correction in an adaptive optics scanning ophthalmoscope.

    Science.gov (United States)

    Sulai, Yusufu N; Dubra, Alfredo

    2014-09-01

    The correction of non-common path aberrations (NCPAs) between the imaging and wavefront sensing channel in a confocal scanning adaptive optics ophthalmoscope is demonstrated. NCPA correction is achieved by maximizing an image sharpness metric while the confocal detection aperture is temporarily removed, effectively minimizing the monochromatic aberrations in the illumination path of the imaging channel. Comparison of NCPA estimated using zonal and modal orthogonal wavefront corrector bases provided wavefronts that differ by ~λ/20 in root-mean-squared (~λ/30 standard deviation). Sequential insertion of a cylindrical lens in the illumination and light collection paths of the imaging channel was used to compare image resolution after changing the wavefront correction to maximize image sharpness and intensity metrics. Finally, the NCPA correction was incorporated into the closed-loop adaptive optics control by biasing the wavefront sensor signals without reducing its bandwidth.

  5. Optical depth sectioning in the aberration-corrected scanning transmission and scanning confocal electron microscope

    International Nuclear Information System (INIS)

    Behan, G; Nellist, P D

    2008-01-01

    The use of spherical aberration correctors in the scanning transmission electron microscope (STEM) has the effect of reducing the depth of field of the microscope, making three-dimensional imaging of a specimen possible by optical sectioning. Depth resolution can be improved further by placing aberration correctors and lenses pre and post specimen to achieve an imaging mode known as scanning confocal electron microscopy (SCEM). We present the calculated incoherent point spread functions (PSF) and optical transfer functions (OTF) of a STEM and SCEM. The OTF for a STEM is shown to have a missing cone region which results in severe blurring along the optic axis, which can be especially severe for extended objects. We also present strategies for reconstruction of experimental data, such as three-dimensional deconvolution of the point spread function.

  6. Design for an aberration corrected scanning electron microscope using miniature electron mirrors.

    Science.gov (United States)

    Dohi, Hideto; Kruit, Pieter

    2018-03-07

    Resolution of scanning electron microscopes (SEMs) is determined by aberrations of the objective lens. It is well known that both spherical and chromatic aberrations can be compensated by placing a 90-degree bending magnet and an electron mirror in the beam path before the objective lens. Nevertheless, this approach has not led to wide use of these aberration correctors, partly because aberrations of the bending magnet can be a serious problem. A mirror corrector with two mirrors placed perpendicularly to the optic axis of an SEM and facing each other is proposed. As a result, only small-angle magnetic deflection is necessary to guide the electron beam around the top mirror to the bottom mirror and around the bottom mirror to the objective lens. The deflection angle, in the order of 50 mrad, is sufficiently small to avoid deflection aberrations. In addition, lateral dispersion at the sample plane can be avoided by making the deflection fields symmetric. Such a corrector system is only possible if the incoming beam can pass the top mirror at a distance in the order of millimeters, without being disturbed by the electric fields of electrodes of the mirror. It is proposed that condition can be satisfied with micro-scale electron optical elements fabricated by using MEMS technology. In the proposed corrector system, the micro-mirrors have to provide the exact negative spherical and chromatic aberrations for correcting the aberration of the objective lens. This exact tuning is accomplished by variable magnification between the micro-mirrors and the objective lens using an additional transfer lens. Extensive optical calculations are reported. Aberrations of the micro-mirrors were analyzed by numerical calculation. Dispersion and aberrations of the deflectors were calculated by using an analytical field model. Combination aberrations caused by the off-axis position of dispersive rays in the mirrors and objective lens were also analyzed. It is concluded that the proposed

  7. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope.

    Science.gov (United States)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I; Nellist, Peter D; Cosgriff, Eireann C; D'Alfonso, Adrian J; Morgan, Andrew J; Allen, Leslie J; Hashimoto, Ayako; Takeguchi, Masaki; Mitsuishi, Kazutaka; Shimojo, Masayuki

    2011-06-01

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Practical spatial resolution of electron energy loss spectroscopy in aberration corrected scanning transmission electron microscopy.

    Science.gov (United States)

    Shah, A B; Ramasse, Q M; Wen, J G; Bhattacharya, A; Zuo, J M

    2011-08-01

    The resolution of electron energy loss spectroscopy (EELS) is limited by delocalization of inelastic electron scattering rather than probe size in an aberration corrected scanning transmission electron microscope (STEM). In this study, we present an experimental quantification of EELS spatial resolution using chemically modulated 2×(LaMnO(3))/2×(SrTiO(3)) and 2×(SrVO(3))/2×(SrTiO(3)) superlattices by measuring the full width at half maxima (FWHM) of integrated Ti M(2,3), Ti L(2,3), V L(2,3), Mn L(2,3), La N(4,5), La N(2,3) La M(4,5) and Sr L(3) edges over the superlattices. The EELS signals recorded using large collection angles are peaked at atomic columns. The FWHM of the EELS profile, obtained by curve-fitting, reveals a systematic trend with the energy loss for the Ti, V, and Mn edges. However, the experimental FWHM of the Sr and La edges deviates significantly from the observed experimental tendency. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Atomic resolution elemental mapping using energy-filtered imaging scanning transmission electron microscopy with chromatic aberration correction.

    Science.gov (United States)

    Krause, F F; Rosenauer, A; Barthel, J; Mayer, J; Urban, K; Dunin-Borkowski, R E; Brown, H G; Forbes, B D; Allen, L J

    2017-10-01

    This paper addresses a novel approach to atomic resolution elemental mapping, demonstrating a method that produces elemental maps with a similar resolution to the established method of electron energy-loss spectroscopy in scanning transmission electron microscopy. Dubbed energy-filtered imaging scanning transmission electron microscopy (EFISTEM) this mode of imaging is, by the quantum mechanical principle of reciprocity, equivalent to tilting the probe in energy-filtered transmission electron microscopy (EFTEM) through a cone and incoherently averaging the results. In this paper we present a proof-of-principle EFISTEM experimental study on strontium titanate. The present approach, made possible by chromatic aberration correction, has the advantage that it provides elemental maps which are immune to spatial incoherence in the electron source, coherent aberrations in the probe-forming lens and probe jitter. The veracity of the experiment is supported by quantum mechanical image simulations, which provide an insight into the image-forming process. Elemental maps obtained in EFTEM suffer from the effect known as preservation of elastic contrast, which, for example, can lead to a given atomic species appearing to be in atomic columns where it is not to be found. EFISTEM very substantially reduces the preservation of elastic contrast and yields images which show stability of contrast with changing thickness. The experimental application is demonstrated in a proof-of-principle study on strontium titanate. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Structural defects in cubic semiconductors characterized by aberration-corrected scanning transmission electron microscopy.

    Science.gov (United States)

    Arroyo Rojas Dasilva, Yadira; Kozak, Roksolana; Erni, Rolf; Rossell, Marta D

    2017-05-01

    The development of new electro-optical devices and the realization of novel types of transistors require a profound understanding of the structural characteristics of new semiconductor heterostructures. This article provides a concise review about structural defects which occur in semiconductor heterostructures on the basis of micro-patterned Si substrates. In particular, one- and two-dimensional crystal defects are being discussed which are due to the plastic relaxation of epitaxial strain caused by the misfit of crystal lattices. Besides a few selected examples from literature, we treat in particular crystal defects occurring in GaAs/Si, Ge/Si and β-SiC/Si structures which are studied by high-resolution annular dark-field scanning transmission electron microscopy. The relevance of this article is twofold; firstly, it should provide a collection of data which are of help for the identification and characterization of defects in cubic semiconductors by means of atomic-resolution imaging, and secondly, the experimental data shall provide a basis for advancing the understanding of device characteristics with the aid of theoretical modelling by considering the defective nature of strained semiconductor heterostructures. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Nanoscale Energy-Filtered Scanning Confocal Electron Microscopy Using a Double-Aberration-Corrected Transmission Electron Microscope

    International Nuclear Information System (INIS)

    Wang Peng; Behan, Gavin; Kirkland, Angus I.; Nellist, Peter D.; Takeguchi, Masaki; Hashimoto, Ayako; Mitsuishi, Kazutaka; Shimojo, Masayuki

    2010-01-01

    We demonstrate that a transmission electron microscope fitted with two spherical-aberration correctors can be operated as an energy-filtered scanning confocal electron microscope. A method for establishing this mode is described and initial results showing 3D chemical mapping with nanoscale sensitivity to height and thickness changes in a carbon film are presented. Importantly, uncorrected chromatic aberration does not limit the depth resolution of this technique and moreover performs an energy-filtering role, which is explained in terms of a combined depth and energy-loss response function.

  12. In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ping

    2014-10-01

    Controlling metallic nanoparticle (NP) interactions plays a vital role in the development of new joining techniques (nanosolder) that bond at lower processing temperatures but remain viable at higher temperatures. The pr imary objective of this project is t o develop a fundamental understanding of the actual reaction processes, associated atomic mechanisms, and the resulting microstructure that occur during thermally - driven bond formation concerning metal - metal nano - scale (%3C50nm) interfaces. In this LDRD pr oject, we have studied metallic NPs interaction at the elevated temperatures by combining in - situ transmission electron microscopy (TEM ) using an aberration - corrected scanning transmission electron microscope (AC - STEM) and atomic - scale modeling such as m olecular dynamic (MD) simulations. Various metallic NPs such as Ag, Cu and Au are synthesized by chemical routines. Numerous in - situ e xperiments were carried out with focus of the research on study of Ag - Cu system. For the first time, using in - situ STEM he ating experiments , we directly observed t he formation of a 3 - dimensional (3 - D) epitaxial Cu - Ag core - shell nanoparticle during the thermal interaction of Cu and Ag NPs at elevated temperatures (150 - 300 o C). The reaction takes place at temperatures as low as 150 o C and was only observed when care was taken to circumvent the effects of electron beam irradiation during STEM imaging. Atomic - scale modeling verified that the Cu - Ag core - shell structure is energetically favored, and indicated that this phenomenon is a nano - scale effect related to the large surface - to - volume ratio of the NPs. The observation potentially can be used for developing new nanosolder technology that uses Ag shell as the "glue" that stic ks the particles of Cu together. The LDRD has led to several journal publications and numerous conference presentations, and a TA. In addition, we have developed new TEM characterization techniques and phase

  13. Morphological evolution of InAs/InP quantum wires through aberration-corrected scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sales, D L; Molina, S I [Departamento de Ciencia de los Materiales e I. M. y Q. I., Universidad de Cadiz, Campus Rio San Pedro, E-11510 Puerto Real, Cadiz (Spain); Varela, M; Pennycook, S J [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Galindo, P L [Departamento de Lenguajes y Sistemas Informaticos, Universidad de Cadiz, Campus Rio San Pedro, E-11510 Puerto Real, Cadiz (Spain); Gonzalez, L; Gonzalez, Y [Instituto de Microelectronica de Madrid (CNM, CSIC), Isaac Newton 8, E-28760 Tres Cantos, Madrid (Spain); Fuster, D, E-mail: david.sales@uca.es [UMDO - Unidad Asociada al CSIC-IMM, Instituto de Ciencia de Materiales, Universidad de Valencia, PO Box 22085, 4607 Valencia (Spain)

    2010-08-13

    Evolution of the size, shape and composition of self-assembled InAs/InP quantum wires through the Stranski-Krastanov transition has been determined by aberration-corrected Z-contrast imaging. High resolution compositional maps of the wires in the initial, intermediate and final formation stages are presented. (001) is the main facet at their very initial stage of formation, which is gradually reduced in favour of {l_brace}114{r_brace} or {l_brace}118{r_brace}, ending with the formation of mature quantum wires with {l_brace}114{r_brace} facets. Significant changes in wire dimensions are measured when varying slightly the amount of InAs deposited. These results are used as input parameters to build three-dimensional models that allow calculation of the strain energy during the quantum wire formation process. The observed morphological evolution is explained in terms of the calculated elastic energy changes at the growth front. Regions of the wetting layer close to the nanostructure perimeters have higher strain energy, causing migration of As atoms towards the quantum wire terraces, where the structure is partially relaxed; the thickness of the wetting layer is reduced in these zones and the island height increases until the (001) facet is removed.

  14. Direct observation of dislocation dissociation and Suzuki segregation in a Mg–Zn–Y alloy by aberration-corrected scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Yang Zhiqing; Chisholm, Matthew F.; Duscher, Gerd; Ma Xiuliang; Pennycook, Stephen J.

    2013-01-01

    Crystal defects in a plastically deformed Mg–Zn–Y alloy have been studied on the atomic scale using aberration-corrected scanning transmission electron microscopy, providing important structural data for understanding the material’s deformation behavior and strengthening mechanisms. Atomic scale structures of deformation stacking faults resulting from dissociation of different types of dislocations have been characterized experimentally, and modeled. Suzuki segregation of Zn and Y along stacking faults formed through dislocation dissociation during plastic deformation at 300 °C is confirmed experimentally on the atomic level. The stacking fault energy of the Mg–Zn–Y alloy is evaluated to be in the range of 4.0–10.3 mJ m −2 . The newly formed nanometer-wide stacking faults with their Zn/Y segregation in Mg grains play an important role in the superior strength of this alloy at elevated temperatures.

  15. Phase and birefringence aberration correction

    Science.gov (United States)

    Bowers, M.; Hankla, A.

    1996-07-09

    A Brillouin enhanced four wave mixing phase conjugate mirror corrects phase aberrations of a coherent electromagnetic beam and birefringence induced upon that beam. The stimulated Brillouin scattering (SBS) phase conjugation technique is augmented to include Brillouin enhanced four wave mixing (BEFWM). A seed beam is generated by a main oscillator which arrives at the phase conjugate cell before the signal beams in order to initiate the Brillouin effect. The signal beam which is being amplified through the amplifier chain is split into two perpendicularly polarized beams. One of the two beams is chosen to be the same polarization as some component of the seed beam, the other orthogonal to the first. The polarization of the orthogonal beam is then rotated 90{degree} such that it is parallel to the other signal beam. The three beams are then focused into cell containing a medium capable of Brillouin excitation. The two signal beams are focused such that they cross the seed beam path before their respective beam waists in order to achieve BEFWM or the two signal beams are focused to a point or points contained within the focused cone angle of the seed beam to achieve seeded SBS, and thus negate the effects of all birefringent and material aberrations in the system. 5 figs.

  16. Design of an aberration corrected low-voltage SEM

    NARCIS (Netherlands)

    Aken, R.H. van; Maas, D.J.; Hagen, C.W.; Barth, J.E.; Kruit, P.

    2010-01-01

    The low-voltage foil corrector is a novel type of foil aberration corrector that can correct for both the spherical and chromatic aberration simultaneously. In order to give a realistic example of the capabilities of this corrector, a design for a low-voltage scanning electron microscope with the

  17. Investigating the chemical and morphological evolution of GaAs capped InAs/InP quantum dots emitting at 1.5μm using aberration-corrected scanning transmission electron microscopy

    DEFF Research Database (Denmark)

    Kadkhodazadeh, Shima; Semenova, Elizaveta; Yvind, Kresten

    2011-01-01

    The emission wavelength of InAs quantum dots grown on InP has been shown to shift to the technologically desirable 1.5μm with the deposition of 1–2 monolayers of GaAs on top of the quantum dots. Here, we use aberration-corrected scanning transmission electron microscopy to investigate morphological...

  18. Puzzling Intergrowth in Cerium Nitridophosphate Unraveled by Joint Venture of Aberration-Corrected Scanning Transmission Electron Microscopy and Synchrotron Diffraction.

    Science.gov (United States)

    Kloß, Simon D; Neudert, Lukas; Döblinger, Markus; Nentwig, Markus; Oeckler, Oliver; Schnick, Wolfgang

    2017-09-13

    Thorough investigation of nitridophosphates has rapidly accelerated through development of new synthesis strategies. Here we used the recently developed high-pressure metathesis to prepare the first rare-earth metal nitridophosphate, Ce 4 Li 3 P 18 N 35 , with a high degree of condensation >1/2. Ce 4 Li 3 P 18 N 35 consists of an unprecedented hexagonal framework of PN 4 tetrahedra and exhibits blue luminescence peaking at 455 nm. Transmission electron microscopy (TEM) revealed two intergrown domains with slight structural and compositional variations. One domain type shows extremely weak superstructure phenomena revealed by atomic-resolution scanning TEM (STEM) and single-crystal diffraction using synchrotron radiation. The corresponding superstructure involves a modulated displacement of Ce atoms in channels of tetrahedra 6-rings. The displacement model was refined in a supercell as well as in an equivalent commensurate (3 + 2)-dimensional description in superspace group P6 3 (α, β, 0)0(-α - β, α, 0)0. In the second domain type, STEM revealed disordered vacancies of the same Ce atoms that were modulated in the first domain type, leading to sum formula Ce 4-0.5x Li 3 P 18 N 35-1.5x O 1.5x (x ≈ 0.72) of the average structure. The examination of these structural intricacies may indicate the detection limit of synchrotron diffraction and TEM. We discuss the occurrence of either Ce displacements or Ce vacancies that induce the incorporation of O as necessary stabilization of the crystal structure.

  19. Pulse compressor with aberration correction

    Energy Technology Data Exchange (ETDEWEB)

    Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States)

    2015-11-30

    In this SBIR project, Electron Optica, Inc. (EOI) is developing an electron mirror-based pulse compressor attachment to new and retrofitted dynamic transmission electron microscopes (DTEMs) and ultrafast electron diffraction (UED) cameras for improving the temporal resolution of these instruments from the characteristic range of a few picoseconds to a few nanoseconds and beyond, into the sub-100 femtosecond range. The improvement will enable electron microscopes and diffraction cameras to better resolve the dynamics of reactions in the areas of solid state physics, chemistry, and biology. EOI’s pulse compressor technology utilizes the combination of electron mirror optics and a magnetic beam separator to compress the electron pulse. The design exploits the symmetry inherent in reversing the electron trajectory in the mirror in order to compress the temporally broadened beam. This system also simultaneously corrects the chromatic and spherical aberration of the objective lens for improved spatial resolution. This correction will be found valuable as the source size is reduced with laser-triggered point source emitters. With such emitters, it might be possible to significantly reduce the illuminated area and carry out ultrafast diffraction experiments from small regions of the sample, e.g. from individual grains or nanoparticles. During phase I, EOI drafted a set of candidate pulse compressor architectures and evaluated the trade-offs between temporal resolution and electron bunch size to achieve the optimum design for two particular applications with market potential: increasing the temporal and spatial resolution of UEDs, and increasing the temporal and spatial resolution of DTEMs. Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key pulse compressor components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded

  20. An electron microscope for the aberration-corrected era

    International Nuclear Information System (INIS)

    Krivanek, O.L.; Corbin, G.J.; Dellby, N.; Elston, B.F.; Keyse, R.J.; Murfitt, M.F.; Own, C.S.; Szilagyi, Z.S.; Woodruff, J.W.

    2008-01-01

    Improved resolution made possible by aberration correction has greatly increased the demands on the performance of all parts of high-end electron microscopes. In order to meet these demands, we have designed and built an entirely new scanning transmission electron microscope (STEM). The microscope includes a flexible illumination system that allows the properties of its probe to be changed on-the-fly, a third-generation aberration corrector which corrects all geometric aberrations up to fifth order, an ultra-responsive yet stable five-axis sample stage, and a flexible configuration of optimized detectors. The microscope features many innovations, such as a modular column assembled from building blocks that can be stacked in almost any order, in situ storage and cleaning facilities for up to five samples, computer-controlled loading of samples into the column, and self-diagnosing electronics. The microscope construction is described, and examples of its capabilities are shown

  1. Correction for polychromatic aberration in computed tomography images

    International Nuclear Information System (INIS)

    Naparstek, A.

    1979-01-01

    A method and apparatus for correcting a computed tomography image for polychromatic aberration caused by the non-linear interaction (i.e. the energy dependent attenuation characteristics) of different body constituents, such as bone and soft tissue, with a polychromatic X-ray beam are described in detail. An initial image is conventionally computed from path measurements made as source and detector assembly scan a body section. In the improvement, each image element of the initial computed image representing attenuation is recorded in a store and is compared with two thresholds, one representing bone and the other soft tissue. Depending on the element value relative to the thresholds, a proportion of the respective constituent is allocated to that element location and corresponding bone and soft tissue projections are determined and stored. An error projection generator calculates projections of polychromatic aberration errors in the raw image data from recalled bone and tissue projections using a multidimensional polynomial function which approximates the non-linear interaction involved. After filtering, these are supplied to an image reconstruction computer to compute image element correction values which are subtracted from raw image element values to provide a corrected reconstructed image for display. (author)

  2. Aberrant Pattern of Scanning in Prosopagnosia Reflects Impaired Face Processing

    Science.gov (United States)

    Stephan, Blossom Christa Maree; Caine, Diana

    2009-01-01

    Visual scanpath recording was used to investigate the information processing strategies used by a prosopagnosic patient, SC, when viewing faces. Compared to controls, SC showed an aberrant pattern of scanning, directing attention away from the internal configuration of facial features (eyes, nose) towards peripheral regions (hair, forehead) of the…

  3. Correcting the Chromatic Aberration in Barrel Distortion of Endoscopic Images

    Directory of Open Access Journals (Sweden)

    Y. M. Harry Ng

    2003-04-01

    Full Text Available Modern endoscopes offer physicians a wide-angle field of view (FOV for minimally invasive therapies. However, the high level of barrel distortion may prevent accurate perception of image. Fortunately, this kind of distortion may be corrected by digital image processing. In this paper we investigate the chromatic aberrations in the barrel distortion of endoscopic images. In the past, chromatic aberration in endoscopes is corrected by achromatic lenses or active lens control. In contrast, we take a computational approach by modifying the concept of image warping and the existing barrel distortion correction algorithm to tackle the chromatic aberration problem. In addition, an error function for the determination of the level of centroid coincidence is proposed. Simulation and experimental results confirm the effectiveness of our method.

  4. Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

    KAUST Repository

    Sun, Tiancheng

    2017-12-25

    Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

  5. Joint denoising, demosaicing, and chromatic aberration correction for UHD video

    Science.gov (United States)

    Jovanov, Ljubomir; Philips, Wilfried; Damstra, Klaas Jan; Ellenbroek, Frank

    2017-09-01

    High-resolution video capture is crucial for numerous applications such as surveillance, security, industrial inspection, medical imaging and digital entertainment. In the last two decades, we are witnessing a dramatic increase of the spatial resolution and the maximal frame rate of video capturing devices. In order to achieve further resolution increase, numerous challenges will be facing us. Due to the reduced size of the pixel, the amount of light also reduces, leading to the increased noise level. Moreover, the reduced pixel size makes the lens imprecisions more pronounced, which especially applies to chromatic aberrations. Even in the case when high quality lenses are used some chromatic aberration artefacts will remain. Next, noise level additionally increases due to the higher frame rates. To reduce the complexity and the price of the camera, one sensor captures all three colors, by relying on Color Filter Arrays. In order to obtain full resolution color image, missing color components have to be interpolated, i.e. demosaicked, which is more challenging than in the case of lower resolution, due to the increased noise and aberrations. In this paper, we propose a new method, which jointly performs chromatic aberration correction, denoising and demosaicking. By jointly performing the reduction of all artefacts, we are reducing the overall complexity of the system and the introduction of new artefacts. In order to reduce possible flicker we also perform temporal video enhancement. We evaluate the proposed method on a number of publicly available UHD sequences and on sequences recorded in our studio.

  6. Geometric distortion correction for sinusoidally scanned images

    International Nuclear Information System (INIS)

    Xu, Lijun; Tian, Xiangrui; Li, Xiaolu; Shang, Guangyi; Yao, Junen

    2011-01-01

    A method for correcting the geometric distortion of sinusoidally scanned images was proposed. The generation mechanism of the geometric distortion in sinusoidally scanned images was analyzed. Based on the relationship between the coordinates of uniformly scanned points and those of sinusoidally scanned points, a transformation formula was obtained for correcting the geometric distortion when the sampling rate was a constant. By comparing the forward method with the inverse method, a hybrid method for correcting the geometric distortion of sinusoidally scanned images was proposed. This method takes advantage of both the forward and inverse methods and was proven to be better than either of them in terms of peak signal-to-noise ratio (PSNR). The time consumed by the hybrid method was between the other two. When a higher PSNR is desired, the hybrid method is recommended if time permits. In addition, it is a universal approach to the correction of geometric distortion of the images scanned in the sinusoidal mode

  7. Aberration-corrected multipole Wien filter for energy-filtered x-ray photoemission electron microscopy

    OpenAIRE

    Niimi, Hironobu; Chun, Wang-Jae; Suzuki, Shushi; Asakura, Kiyotaka; Kato, Makoto

    2007-01-01

    The aberration of a multipole Wien filter for energy-filtered x-ray photoemission electron microscopy was analyzed and the optimized Fourier components of the electric and magnetic fields for the third-order aperture aberration corrections were obtained. It was found that the third-order aperture aberration correction requires 12 electrodes and magnetic poles. ©2007 American Institute of Physics

  8. Aberration-corrected multipole Wien filter for energy-filtered x-ray photoemission electron microscopy

    Science.gov (United States)

    Niimi, Hironobu; Chun, Wang-Jae; Suzuki, Shushi; Asakura, Kiyotaka; Kato, Makoto

    2007-06-01

    The aberration of a multipole Wien filter for energy-filtered x-ray photoemission electron microscopy was analyzed and the optimized Fourier components of the electric and magnetic fields for the third-order aperture aberration corrections were obtained. It was found that the third-order aperture aberration correction requires 12 electrodes and magnetic poles.

  9. Image transfer with spatial coherence for aberration corrected transmission electron microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Hosokawa, Fumio, E-mail: hosokawa@bio-net.co.jp [BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo (Japan); Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503 (Japan); Sawada, Hidetaka [JEOL (UK) Ltd., JEOL House, Silver Court, Watchmead, Welwyn Garden City, Herts AL7 1LT (United Kingdom); Shinkawa, Takao [BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo (Japan); Sannomiya, Takumi [Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503 (Japan)

    2016-08-15

    The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field’s components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field’s derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. - Highlights: • The formula of partial coherence for aberration corrected TEM is derived. • Transfer functions are calculated with several residual aberrations. • The calculated transfer function shows the characteristic damping. • The odd-symmetric wave aberrations can cause the attenuation of image via coherence. • The examples of aberration corrected TEM image simulations are shown.

  10. Image transfer with spatial coherence for aberration corrected transmission electron microscopes.

    Science.gov (United States)

    Hosokawa, Fumio; Sawada, Hidetaka; Shinkawa, Takao; Sannomiya, Takumi

    2016-08-01

    The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field's components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field's derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Simulation on a new method of low-frequency phase aberration correction

    CERN Document Server

    Deng Qing Hua; Jing Feng; LiuLanQin

    2002-01-01

    A kind of new phase aberration correcting method is introduced--using a phase countervailing mirror to correct the low-frequency phase error. This method is mainly aimed to correct the static phase aberration caused by the fishing error on the optics. With random phase screen simulating the low-frequency phase aberration of the amplifiers, and the other effect of amplifiers on the beam is neglected, a beam propagation is set up. A new concept of equivalent phase plate is introduced and the phase of the mirror, as the invert phase of the equivalent phase plate, is easy to get. Finally, simulation of the correcting course was done

  12. Correcting the wavefront aberration of membrane mirror based on liquid crystal spatial light modulator

    Science.gov (United States)

    Yang, Bin; Wei, Yin; Chen, Xinhua; Tang, Minxue

    2014-11-01

    Membrane mirror with flexible polymer film substrate is a new-concept ultra lightweight mirror for space applications. Compared with traditional mirrors, membrane mirror has the advantages of lightweight, folding and deployable, low cost and etc. Due to the surface shape of flexible membrane mirror is easy to deviate from the design surface shape, it will bring wavefront aberration to the optical system. In order to solve this problem, a method of membrane mirror wavefront aberration correction based on the liquid crystal spatial light modulator (LCSLM) will be studied in this paper. The wavefront aberration correction principle of LCSLM is described and the phase modulation property of a LCSLM is measured and analyzed firstly. Then the membrane mirror wavefront aberration correction system is designed and established according to the optical properties of a membrane mirror. The LCSLM and a Hartmann-Shack sensor are used as a wavefront corrector and a wavefront detector, respectively. The detected wavefront aberration is calculated and converted into voltage value on LCSLM for the mirror wavefront aberration correction by programming in Matlab. When in experiment, the wavefront aberration of a glass plane mirror with a diameter of 70 mm is measured and corrected for verifying the feasibility of the experiment system and the correctness of the program. The PV value and RMS value of distorted wavefront are reduced and near diffraction limited optical performance is achieved. On this basis, the wavefront aberration of the aperture center Φ25 mm in a membrane mirror with a diameter of 200 mm is corrected and the errors are analyzed. It provides a means of correcting the wavefront aberration of membrane mirror.

  13. Outline of an aberration correct optical channel without space charge

    International Nuclear Information System (INIS)

    Bruck, H.

    1978-01-01

    A beam transport line is described which guides a particle bunch from a storage ring to the target, located at the center of the ring, for heavy ion fusion. The device was conceived to prevent spectral analysis and coma aberration, owing to the deflecting sector, and also chromatic and spherical aberrations. Space charge is not considered here. The device includes the following elements: (1) extraction from the storage ring, (2) adaptation to (3) the deflecting magnet sector, (4) collimator lens, and (5) 10m drift space to the target plane

  14. Angstrom analysis with dynamic in-situ aberration corrected electron microscopy

    International Nuclear Information System (INIS)

    Gai, P L; Boyes, E D

    2010-01-01

    Following the pioneering development of atomic resolution in-situ environmental TEM (ETEM) for direct probing of gas-solid reactions, recent developments are presented of dynamic real time in-situ studies at the Angstrom level in an aberration corrected electron microscope. The in-situ data from Pt-Pd nanoparticles on carbon with the corresponding FFT/optical diffractogram (OD) illustrate an achieved resolution of 0 C and higher, in a double aberration corrected JEOL 2200 FS TEM/STEM employing a wider gap objective pole piece and gas tolerant TMP column pumping system. Direct observations of dynamic biofuel catalysts under controlled calcinations conditions and quantified with catalytic reactivity and physico-chemical studies show the benefits in-situ aberration correction in unveiling the evolution of surface active sites necessary for the development efficient heterogeneous catalysts. The new results open up opportunities for dynamic studies of materials in an aberration corrected environment and direct future development activities.

  15. Comparison of wavefront aberrations under cycloplegic, scotopic and photopic conditions using WaveScan

    Directory of Open Access Journals (Sweden)

    Rong Fan

    2012-04-01

    Full Text Available PURPOSE: To evaluate the differences of wavefront aberrations under cycloplegic, scotopic and photopic conditions. METHODS: A total of 174 eyes of 105 patients were measured using the wavefront sensor (WaveScan® 3.62 under different pupil conditions: cycloplegic 8.58 ± 0.54 mm (6.4 mm - 9.5 mm, scotopic 7.53 ± 0.69 mm (5.7 mm - 9.1 mm and photopic 6.08 ± 1.14 mm (4.1 mm - 8.8 mm. The pupil diameter, standard Zernike coefficients, root mean square of higher-order aberrations and dominant aberrations were compared between cycloplegic and scotopic conditions, and between scotopic and photopic conditions. RESULTS: The pupil diameter was 7.53 ± 0.69 mm under the scotopic condition, which reached the requirement of about 6.5 mm optical zone design in the wavefront-guided surgery and prevented measurement error due to the pupil centroid shift caused by mydriatics. Pharmacological pupil dilation induced increase of standard Zernike coefficients Z3-3, Z4(0 and Z5-5. The higher-order aberrations, third-order aberration, fourth-order aberration, fifth-order aberration, sixth-order aberration, and spherical aberration increased statistically significantly, compared to the scotopic condition (P<0.010. When the scotopic condition shifted to the photopic condition, the standard Zernike coefficients Z4(0, Z4², Z6-4, Z6-2, Z6² decreased and all the higher-order aberrations decreased statistically significantly (P<0.010, demonstrating that accommodative miosis can significantly improve vision under the photopic condition. Under the three conditions, the vertical coma aberration appears the most frequently within the dominant aberrations without significant effect by pupil size variance, and the proportion of spherical aberrations decreased with the decrease of the pupil size. CONCLUSIONS: The wavefront aberrations are significantly different under cycloplegic, scotopic and photopic conditions. Using the wavefront sensor (VISX WaveScan to measure scotopic

  16. Membrane-based aberration-corrected tunable micro-lenses

    Science.gov (United States)

    Waibel, Philipp; Ermantraut, Eugen; Mader, Daniel; Zappe, Hans; Seifert, Andreas

    2010-05-01

    We present measurements and simulations of membrane-based micro-lens stacks, tunable in focal length in the range of 10mm to 50mm without chromatic aberration. The pressure-actuated, liquid-filled, membrane-based micro-lenses are fabricated by an all-silicone molding approach and consist of three chambers separated by two highly flexible silicone-membranes. Based on the idea of the classical achromatic Fraunhofer doublet, two different liquids with suitable optical properties are used. Pressure-dependent surface topologies are measured by profilometry for determining the correlation between refraction and applied pressure. The profiles are fit to polynomials; the coefficients of the polynomials are pressure-dependent and fit to empirically determined functions which are then used as an input for optical ray-tracing. Using this approach, the focal length is tunable while compensating for chromatic aberration by suitably applied pressures.

  17. Effects of SMILE and Trans-PRK on corneal higher order aberrations after myopic correction

    Directory of Open Access Journals (Sweden)

    Jiao Zhao

    2018-02-01

    Full Text Available AIM:To observe the effects of small incision lenticule extraction(SMILEand trans-epithelial photorefractive keratectomy(Trans-PRKon corneal horizontal coma, vertical coma, and spherical aberration and total higher order aberrations after refractive correction for myopia. METHODS: This was a prospective non-randomized cohort study. The cohort included 40 patients(80 eyeswith myopia, who received refraction correction surgery from December 2016 to February 2017 in Leshan Ophthalmic Center. Twenty patients(40 eyesreceived SMILE surgery and the other 20 patients(40 eyesreceived Trans-PRK surgery. Corneal aberrations were determined by a high-resolution Pentacam Scheimpflug camera before the surgery and at 1 and 3mo after the operation. Statistical analyses were performed using analysis of variance of repeated measures. RESULTS: At 1 and 3mo post-operation, the uncorrected visual acuity in both groups was better than or equal to the preoperative best corrected visual acuity. The preoperative corneal aberrations showed no significant difference between the two groups(P>0.05. Significantly higher aberration was found after the surgery in both groups(PP>0.05. Post-operation, horizontal and vertical coma had no significant difference between the two groups(P>0.05, while SMILE group showed lower spherical aberration and lower total higher order aberration than Trans-PRK group(PCONCLUSION: Both SMILE and Trans-PRK increase corneal aberration and their effects on horizontal and vertical coma are similar. However, SMILE has a minor influence on spherical aberration and total high order aberration than Trans-PRK.

  18. Environmental Transmission Electron Microscopy in an Aberration-Corrected Environment

    DEFF Research Database (Denmark)

    Hansen, Thomas W.; Wagner, Jakob B.

    2012-01-01

    The increasing use of environmental transmission electron microscopy (ETEM) in materials science provides exciting new possibilities for investigating chemical reactions and understanding both the interaction of fast electrons with gas molecules and the effect of the presence of gas on high......-resolution imaging. A gaseous atmosphere in the pole-piece gap of the objective lens of the microscope alters both the incoming electron wave prior to interaction with the sample and the outgoing wave below the sample. Whereas conventional TEM samples are usually thin (below 100 nm), the gas in the environmental...... cell fills the entire gap between the pole pieces and is thus not spatially localized. By using an FEI Titan environmental transmission electron microscope equipped with a monochromator and an aberration corrector on the objective lens, we have investigated the effects on imaging and spectroscopy...

  19. A new aberration correction method for photoemission electron microscopy by means of moving focus

    International Nuclear Information System (INIS)

    Koshikawa, T; Shimizu, H; Amakawa, R; Ikuta, T; Yasue, T; Bauer, E

    2005-01-01

    A new aberration correction method has been developed for photoemission electron microscopy (PEEM). In order to correct the spherical and chromatic aberrations, a moving focus method was adopted. Several experimental limitations to achieving optimal resolution have also been overcome. A high brightness Hg lamp system has been developed to overcome the insufficient brightness of the conventional Hg lamp. An improvement of brightness by over 100 times as compared with the conventional lamp was achieved. Image blur was also found due to a weak environmental AC magnetic field caused by essential microscope components, i.e., the power transformer and CCD camera. After implementing the high brightness lamp and eliminating stray magnetic field by proper shielding, preliminary experiments demonstrate that aberration correction by moving focus can improve the PEEM image resolution

  20. Angstrom analysis with dynamic in-situ aberration corrected electron microscopy

    Science.gov (United States)

    Gai, P. L.; Boyes, E. D.

    2010-07-01

    Following the pioneering development of atomic resolution in-situ environmental TEM (ETEM) for direct probing of gas-solid reactions, recent developments are presented of dynamic real time in-situ studies at the Angstrom level in an aberration corrected electron microscope. The in-situ data from Pt-Pd nanoparticles on carbon with the corresponding FFT/optical diffractogram (OD) illustrate an achieved resolution of biofuel catalysts under controlled calcinations conditions and quantified with catalytic reactivity and physico-chemical studies show the benefits in-situ aberration correction in unveiling the evolution of surface active sites necessary for the development efficient heterogeneous catalysts. The new results open up opportunities for dynamic studies of materials in an aberration corrected environment and direct future development activities.

  1. Dynamic changes in higher-order aberrations after correction of lower-order aberrations with adaptive optics in myopic and emmetropic eyes.

    Science.gov (United States)

    Jiang, Yanglin; Wang, Yan; Zhang, Jiamei; Chen, Xiaoqin; Li, Lihua; Zhao, Haoxin; Wang, Rui; Dai, Yun

    2018-01-20

    This study investigated the instantaneous changes of higher-order aberrations (HOAs) following lower-order aberrations (LOAs) correction with a closed-loop adaptive optics (AO) system in myopic and emmetropic eyes. Data were analyzed using generalized additive mixed models. Time-related changes in HOAs were modeled with two-piecewise linear regressions and were compared between myopic and emmetropic eyes. Both vertical coma and spherical aberrations shifted to the positive direction immediately after LOA correction. The fluctuations of the above values were significantly faster in myopic than in emmetropic eyes. Understanding these changes in HOAs following LOA correction may help in achieving better visual outcomes.

  2. Correction of chromatic and geometric aberrations using sextupoles and octupoles

    International Nuclear Information System (INIS)

    Colton, E.

    1978-01-01

    The procedure for applying some chromatic corrections to a final transport line, neglecting space charge, utilizing the method suggested by Brown is described. The possibility of including octupoles into a point-to-point triplet system, as outlined by Fenster is studied. Positive results were obtained in both cases: (i) using 2 + I correcting sections with two pairs of non-interlaced sextupoles increased the fraction of beam with ΔP/P = 1% onto a 0.1 cm radius target by more than a factor of 1.75; (ii) six octupoles placed into a point-to-point triplet system increased the fraction of a full emittance ΔP/P = 0% beam striking a 0.1 cm radius target by a factor of 2.5

  3. Present status and future prospects of spherical aberration corrected TEM/STEM for study of nanomaterials

    International Nuclear Information System (INIS)

    Tanaka, Nobuo

    2008-01-01

    The present status of Cs-corrected TEM/STEM is described from the viewpoint of the observation of nanomaterials. Characteristic features in TEM and STEM are explained using the experimental data obtained by our group and other research groups. Cs correction up to the 3rd-order aberration of an objective lens has already been established and research interest is focused on correcting the 5th-order spherical aberration and the chromatic aberration in combination with the development of a monochromator below an electron gun for smaller point-to-point resolution in optics. Another fundamental area of interest is the limitation of TEM and STEM resolution from the viewpoint of the scattering of electrons in crystals. The minimum size of the exit-wave function below samples undergoing TEM imaging is determined from the calculation of scattering around related atomic columns in the crystals. STEM does not have this limitation because the resolution is, in principle, determined by the probe size. One of the future prospects of Cs-corrected TEM/STEM is the possibility of extending the space around the sample holder by correcting the chromatic and spherical aberrations. This wider space will contribute to the ease of performing in situ experiments and various combinations of TEM and other analysis methods. High-resolution, in situ dynamic and 3D observations/analysis are the most important keywords in the next decade of high-resolution electron microscopy. (topical review)

  4. Multifractality in steady-state accommodation is robust to dynamic correction of aberrations using adaptive optics

    Science.gov (United States)

    Hampson, Karen M.; Mallen, Edward A. H.

    2012-07-01

    When fixating on a stationary object, the human eye exhibits microfluctuations in accommodation. Changes in the magnitude of these fluctuations reflect changes in the accommodation control system. We used adaptive optics to determine the effect of monochromatic aberration dynamics on the control of steady-state accommodation of four subjects. The subjects viewed a stationary stimulus at 2 D while selective Zernike aberrations were corrected. The fluctuations in accommodation were characterised using a wavelet-based multifractal formalism approach. We found that for all subjects, and all experimental conditions, the accommodative fluctuations were multifractal. For one subject, we found that the width of the multifractal spectrum was statistically significantly larger when even-order aberrations were corrected as compared to no aberrations corrected. Hence, in general, for the subjects tested, the multifractal nature of steady-state accommodation control is unaffected by the manipulation of monochromatic aberration dynamics. Averaging across all subjects and experimental conditions, the mean spectrum was right-skewed with a most frequently occurring Hölder exponent of 0.31 ± 0.08. Future applications of multifractal analysis to accommodation control are discussed.

  5. A lateral chromatic aberration correction system for ultrahigh-definition color video camera

    Science.gov (United States)

    Yamashita, Takayuki; Shimamoto, Hiroshi; Funatsu, Ryohei; Mitani, Kohji; Nojiri, Yuji

    2006-02-01

    We have developed color camera for an 8k x 4k-pixel ultrahigh-definition video system, which is called Super Hi- Vision, with a 5x zoom lens and a signal-processing system incorporating a function for real-time lateral chromatic aberration correction. The chromatic aberration of the lens degrades color image resolution. So in order to develop a compact zoom lens consistent with ultrahigh-resolution characteristics, we incorporated a real-time correction function in the signal-processing system. The signal-processing system has eight memory tables to store the correction data at eight focal length points on the blue and red channels. When the focal length data is inputted from the lens control units, the relevant correction data are interpolated from two of eights correction data tables. This system performs geometrical conversion on both channels using this correction data. This paper describes that the correction function can successfully reduce the lateral chromatic aberration, to an amount small enough to ensure the desired image resolution was achieved over the entire range of the lens in real time.

  6. Spherical aberration correction with an in-lens N-fold symmetric line currents model.

    Science.gov (United States)

    Hoque, Shahedul; Ito, Hiroyuki; Nishi, Ryuji

    2018-04-01

    In our previous works, we have proposed N-SYLC (N-fold symmetric line currents) models for aberration correction. In this paper, we propose "in-lens N-SYLC" model, where N-SYLC overlaps rotationally symmetric lens. Such overlap is possible because N-SYLC is free of magnetic materials. We analytically prove that, if certain parameters of the model are optimized, an in-lens 3-SYLC (N = 3) doublet can correct 3rd order spherical aberration. By computer simulation, we show that the required excitation current for correction is less than 0.25 AT for beam energy 5 keV, and the beam size after correction is smaller than 1 nm at the corrector image plane for initial slope less than 4 mrad. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. A new aberration-corrected, energy-filtered LEEM/PEEM instrument II. Operation and results

    International Nuclear Information System (INIS)

    Tromp, R.M.; Hannon, J.B.; Wan, W.; Berghaus, A.; Schaff, O.

    2013-01-01

    In Part I we described a new design for an aberration-corrected Low Energy Electron Microscope (LEEM) and Photo Electron Emission Microscope (PEEM) equipped with an in-line electron energy filter. The chromatic and spherical aberrations of the objective lens are corrected with an electrostatic electron mirror that provides independent control of the chromatic and spherical aberration coefficients C c and C 3 , as well as the mirror focal length. In this Part II we discuss details of microscope operation, how the microscope is set up in a systematic fashion, and we present typical results. - Highlights: ► The C c and C 3 aberrations of a LEEM/PEEM instrument are corrected with an electrostatic electron mirror. ► The mirror provides independent control over C c , C 3 and focal length in close agreement with theory. ► A detailed alignment procedure for the corrected microscope is given. ► Novel methods to measure C c and C 3 of the objective lens and the mirror are presented. ► We demonstrate a record spatial resolution of 2 nm

  8. Aberration-corrected imaging of active sites on industrial catalyst nanoparticles

    DEFF Research Database (Denmark)

    Gontard, Lionel Cervera; Chang, L-Y; Hetherington, CJD

    2007-01-01

    Picture perfect: Information about the local topologies of active sites on commercial nanoparticles can be gained with atomic resolution through spherical-aberration-corrected transmission electron microscopy (TEM). A powder of Pt nanoparticles on carbon black was examined with two advanced TEM t...

  9. Corneal aberrations in normal and keratoconic eyes using an OPD-Scan

    Directory of Open Access Journals (Sweden)

    Mohammad Naderan

    2018-04-01

    Full Text Available AIM: To evaluate higher order aberrations(HOAsof the corneal surface in normal and keratoconic eyes.METHODS: Using an OPD-Scan Ⅱ wavefront analyzer, aberrometric parameters of the corneal surface in one eye of 80 patients with keratoconus(KCand 91 participants with normal eyes were evaluated. The Zernike coefficients from third- to sixth-order as well as root mean square(RMSof primary coma, coma-like aberrations, and total HOA were calculated and compared between both groups.RESULTS: Statistically significant differences were found in all aberrometric parameters between the measurements of the KC and normal participants(PPCONCLUSION: Corneal wavefront measurements by means of OPD-Scan Ⅱ were significantly higher in keratoconic corneas than normal corneas.

  10. Octopole correction of geometric aberrations for high-current heavy-ion fusion beams

    Energy Technology Data Exchange (ETDEWEB)

    Ho, D.D.M.; Haber, I.; Crandall, K.R.; Brandon, S.T.

    1989-03-17

    The success of heavy-ion fusion depends critically on the ability to focus heavy-ion beams to millimeter-size spots. Third-order geometric aberrations caused by fringe fields of the final focusing quadrupoles can significantly distort the focal spot size calculated by first-order theory. We present a method to calculate the locations and strengths of the octopoles that are needed to correct these aberrations. Calculation indicates that the strengths of the octopoles are substantially less than that of the final focusing quadrupoles. 9 refs., 1 fig.

  11. Magnitude of speed of sound aberration corrections for ultrasound image guided radiotherapy for prostate and other anatomical sites

    International Nuclear Information System (INIS)

    Fontanarosa, Davide; Meer, Skadi van der; Bloemen-van Gurp, Esther; Stroian, Gabriela; Verhaegen, Frank

    2012-01-01

    Purpose: The purpose of this work is to assess the magnitude of speed of sound (SOS) aberrations in three-dimensional ultrasound (US) imaging systems in image guided radiotherapy. The discrepancy between the fixed SOS value of 1540 m/s assumed by US systems in human soft tissues and its actual nonhomogeneous distribution in patients produces small but systematic errors of up to a few millimeters in the positions of scanned structures. Methods: A correction, provided by a previously published density-based algorithm, was applied to a set of five prostate, five liver, and five breast cancer patients. The shifts of the centroids of target structures and the change in shape were evaluated. Results: After the correction the prostate cases showed shifts up to 3.6 mm toward the US probe, which may explain largely the reported positioning discrepancies in the literature on US systems versus other imaging modalities. Liver cases showed the largest changes in volume of the organ, up to almost 9%, and shifts of the centroids up to more than 6 mm either away or toward the US probe. Breast images showed systematic small shifts of the centroids toward the US probe with a maximum magnitude of 1.3 mm. Conclusions: The applied correction in prostate and liver cancer patients shows positioning errors of several mm due to SOS aberration; the errors are smaller in breast cancer cases, but possibly becoming more important when breast tissue thickness increases.

  12. Aberration correction in photoemission microscopy and applications in photonics and plasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Koenenkamp, Rolf [Portland State Univ., Portland, OR (United States)

    2017-09-28

    We report on the design, assembly, operation and application of an aberration-corrected photoemission electron microscope. The instrument used novel hyperbolic mirror-correctors with two and three electrodes that allowed simultaneous correction of spherical and chromatic aberrations. A spatial resolution of 5.4nm was obtained with this instrument in 2009, and 4.7nm in subsequent years. New imaging methodology was introduced involving interferometric imaging of light diffraction. This methodology was applied in nano-photonics and in the characterization of surface-plasmon polaritons. Photonic crystals and waveguides, optical antennas and new plasmonic devices such as routers, localizers and filters were designed and demonstrated using the new capabilities offered by the microscope.

  13. Apparatus for and method of correcting for aberrations in a light beam

    International Nuclear Information System (INIS)

    Sawicki, R.H.

    1996-01-01

    A technique for adjustably correcting for aberrations in a light beam is disclosed herein. This technique utilizes first means which defines a flat, circular light reflecting surface having opposite reinforced circumferential edges and a central post and which is resiliently distortable, to a limited extent, into different concave and/or convex curvatures, which may be Gaussian-like, about the central axis, and second means acting on the first means for adjustably distorting the light reflecting surface into a particular selected one of the different curvatures depending upon the aberrations to be corrected for and for fixedly maintaining the curvature selected. In the embodiment disclosed, the light reflecting surface is adjustably distorted into the selected curvature by application of particular axial moments to the central post on the opposite side from the light reflecting surface and lateral moments to the circumference of the reflecting surface. 8 figs

  14. Corneal wavefront-guided LASIK retreatments for correction of highly aberrated corneas following refractive surgery.

    Science.gov (United States)

    Alió, Jorge; Galal, Ahmed; Montalbán, Raúl; Piñero, David

    2007-10-01

    To investigate the safety and efficacy of customized corneal wavefront-guided retreatment in symptomatic patients with highly aberrated corneas following LASIK. This prospective study included 75 eyes of 59 patients with significant visual symptoms who underwent LASIK for the correction of residual refractive error. Ablation profiles were calculated using CSO corneal topography and ESIRIS/Schwind laser platform. Eyes were divided into two groups: those with significant night vision symptoms (37 eyes; night symptoms group) and those with decentration, irregular ablation profile, and flap complications (38 eyes; corneal complications group). Corneal topography and aberrations, visual acuity, point spread function (PSF), refractive outcome, and subjective symptoms were evaluated preoperatively, and 1, 3, and 6 months postoperatively. Mean uncorrected visual acuity was 20/32 preoperatively and 20/25 at 6 months postoperatively in the night symptoms group and 20/40 preoperatively and 20/30 at 6 months postoperatively in the corneal complications group. Mean best spectacle-corrected visual acuity was 20/25 both preoperatively and 6 months postoperatively in both groups (t test, P = .219 and P = .149 for the night symptoms and corneal complications groups, respectively). Safety index was 1.1 in both groups, and efficacy index was 0.93 and 0.92, respectively. Statistically significant improvement of total corneal higher order aberrations, tilt, and improvement of spherical aberrations and coma were observed, with corresponding improvement of PSF. Corneal wavefront-guided LASIK retreatment with CSO topography, ORK-W software, and ESIRIS/Schwind laser platform is safe and effective for treating symptomatic patients affected by corneal higher order aberrations or corneal irregularities following LASIK surgery.

  15. The importance of induced aberrations in the correction of secondary color

    Science.gov (United States)

    Rogers, John R.

    2013-02-01

    Much publicity has been given to the art and science of choosing glass types for the reduction of secondary color, particularly for systems (such as achromats) in which all the elements are in contact. Although it has long been recognized that airspaces between elements can influence chromatic aberration and can even be used to reduce or correct secondary color, comparatively, little emphasis has been placed on this in the published literature. This tutorial is intended to call attention to the induced component of secondary color and suggests methods for improving color correction.

  16. Correction of 157-nm lens based on phase ring aberration extraction method

    Science.gov (United States)

    Meute, Jeff; Rich, Georgia K.; Conley, Will; Smith, Bruce W.; Zavyalova, Lena V.; Cashmore, Julian S.; Ashworth, Dominic; Webb, James E.; Rich, Lisa

    2004-05-01

    Early manufacture and use of 157nm high NA lenses has presented significant challenges including: intrinsic birefringence correction, control of optical surface contamination, and the use of relatively unproven materials, coatings, and metrology. Many of these issues were addressed during the manufacture and use of International SEMATECH"s 0.85NA lens. Most significantly, we were the first to employ 157nm phase measurement interferometry (PMI) and birefringence modeling software for lens optimization. These efforts yielded significant wavefront improvement and produced one of the best wavefront-corrected 157nm lenses to date. After applying the best practices to the manufacture of the lens, we still had to overcome the difficulties of integrating the lens into the tool platform at International SEMATECH instead of at the supplier facility. After lens integration, alignment, and field optimization were complete, conventional lithography and phase ring aberration extraction techniques were used to characterize system performance. These techniques suggested a wavefront error of approximately 0.05 waves RMS--much larger than the 0.03 waves RMS predicted by 157nm PMI. In-situ wavefront correction was planned for in the early stages of this project to mitigate risks introduced by the use of development materials and techniques and field integration of the lens. In this publication, we document the development and use of a phase ring aberration extraction method for characterizing imaging performance and a technique for correcting aberrations with the addition of an optical compensation plate. Imaging results before and after the lens correction are presented and differences between actual and predicted results are discussed.

  17. Correction of polarization error in scanned array weather radar antennas

    NARCIS (Netherlands)

    Pang, C.; Hoogeboom, P.; Russchenberg, H.; Wang, T.; Dong, J.; Wang, X.

    2014-01-01

    In this paper, the polarization error correction of dual-polarized planar scanned array weather radar in alternately transmitting and simultaneously receiving (ATSR) mode is analyzed. A method based on point correction and a method taking the complete array patterns into account are discussed. To

  18. Investigation of focusing and correcting aberrations with binary amplitude and polarization modulation.

    Science.gov (United States)

    Fiala, Peter; Li, Yunqi; Dorrer, Christophe

    2018-02-01

    We investigate the focusing and correcting wavefront aberration of an optical wave using binary amplitude and polarization modulation. Focusing is performed by selectively modulating the field in different zones of the pupil to obtain on-axis constructive interference at a given distance. The conventional Soret zone plate (binary amplitude profile) is expanded to a polarization Soret zone plate with twice the focusing efficiency. Binary pixelated devices that approximate the sinusoidal transmission profile of a Gabor zone plate by spatial dithering are also investigated with amplitude and polarization modulation. Wavefront aberrations are corrected by modulation of the field in the pupil plane to prevent destructive interference in the focal plane of an ideal focusing element. Polarization modulation improves the efficiency obtained by amplitude-only modulation, with a gain that depends on the aberration. Experimental results obtained with Cr-on-glass devices for amplitude modulation and liquid crystal devices operating in the Mauguin condition for polarization modulation are in very good agreement with simulations.

  19. Calibration and digital correction of aberrations in combined optical systems with interchangeable parts

    Science.gov (United States)

    Milde, T.

    2017-06-01

    For many optical systems, mainly in photography, the digital correction of distortion and lateral color aberration is a common step in the image processing pipeline. It is based on images of calibration targets and the determination of coefficients for a correction model. These coefficients are specific for the optical system which forms the aerial image for the sensor. If an exchange of the optical system is necessary, e.g. for offering optics for several applications like macro mode, wide-angle or tele-photo, the entire optical system is typically exchanged and not only parts of it. Using a technique for digital identification of the optical system, e.g. via an electronic interface, the corresponding correction coefficients can be obtained and applied. If the optical system to be exchanged is only a part of the entire optical system, the situation is more difficult. As an example, this is the case in the field of digital microscopy, where objective lenses with different numerical apertures and magnifications are available for the same microscopic body. These objective lenses are no image forming optical systems and need at least a tube lens to produce an image for capturing with a sensor. Both optical systems produce contributions to the resulting overall aberrations, e.g. distortion and lateral color aberration. For a particular pairing, coefficients for a correction model can be calibrated and applied. But in the case of an exchange of the objective, only a part of the optical system changes and a new calibration is needed. We will show how this problem can be solved using a mathematical operation and individual calibration of the distinct parts of the optical system. The advantage is, that the parts of the optical system can be arbitrarily combined and the correction-model coefficients of the combination can be computed from the corresponding coefficients of the individual parts. Hence, there's no need to calibrate every possible combination or to manage a

  20. Numerical correction of anti-symmetric aberrations in single HRTEM images of weakly scattering 2D-objects

    International Nuclear Information System (INIS)

    Lehtinen, Ossi; Geiger, Dorin; Lee, Zhongbo; Whitwick, Michael Brian; Chen, Ming-Wei; Kis, Andras; Kaiser, Ute

    2015-01-01

    Here, we present a numerical post-processing method for removing the effect of anti-symmetric residual aberrations in high-resolution transmission electron microscopy (HRTEM) images of weakly scattering 2D-objects. The method is based on applying the same aberrations with the opposite phase to the Fourier transform of the recorded image intensity and subsequently inverting the Fourier transform. We present the theoretical justification of the method, and its verification based on simulated images in the case of low-order anti-symmetric aberrations. Ultimately the method is applied to experimental hardware aberration-corrected HRTEM images of single-layer graphene and MoSe 2 resulting in images with strongly reduced residual low-order aberrations, and consequently improved interpretability. Alternatively, this method can be used to estimate by trial and error the residual anti-symmetric aberrations in HRTEM images of weakly scattering objects

  1. Aberration correction during real time in vivo imaging of bone marrow with sensorless adaptive optics confocal microscope.

    Science.gov (United States)

    Wang, Zhibin; Wei, Dan; Wei, Ling; He, Yi; Shi, Guohua; Wei, Xunbin; Zhang, Yudong

    2014-08-01

    We have demonstrated adaptive correction of specimen-induced aberration during in vivo imaging of mouse bone marrow vasculature with confocal fluorescence microscopy. Adaptive optics system was completed with wavefront sensorless correction scheme based on stochastic parallel gradient descent algorithm. Using image sharpness as the optimization metric, aberration correction was performed based upon Zernike polynomial modes. The experimental results revealed the improved signal and resolution leading to a substantially enhanced image contrast with aberration correction. The image quality of vessels at 38- and 75-μm depth increased three times and two times, respectively. The corrections allowed us to detect clearer bone marrow vasculature structures at greater contrast and improve the signal-to-noise ratio.

  2. Aberration correction by nonlinear beam mixing: generation of a pseudo point sound source.

    Science.gov (United States)

    Seo, Jongbum; Choi, J J; Fowlkes, J Brian; O'Donnell, Matthew; Cain, Charles A

    2005-11-01

    Nonlinear beam mixing with microbubbles was explored to create a pseudo point source for aberration correction of therapeutic ultrasound. A damping coefficient for a bubble driven by a dual frequency sound field was derived by revisiting Prosperetti's linearized damping model. As a result, the overall damping term for dual frequency was obtained by linear summation of two damping terms for each frequency. The numerical simulation based on the bubble model suggests that the most efficient size range to generate a 1 MHz frequency from 4 MHz and 5 MHz sound sources is 2.6 to 3.0 microm. Furthermore, this size range constitutes the primary distribution of a specific ultrasound contrast agent. When a chamber of 0.1% of the diluted agent is sonified by 4 MHz and 5 MHz sound beams with 80 degrees incident angle between them, an approximately 100 Pa, 1 MHz difference frequency signal can be measured approximately 10 cm away. In addition, the received 1 MHz difference frequency signal shows omni-directional characteristics, even though the overlap zone of the two sound beams is on the order of the difference frequency wavelength. Therefore, the induced sound source can be considered as a pseudo point source and is expected to be useful for aberration correction for therapeutic ultrasound.

  3. Coherence and diffraction limited resolution in microscopic OCT by a unified approach for the correction of dispersion and aberrations

    Science.gov (United States)

    Schulz-Hildebrandt, H.; Münter, Michael; Ahrens, M.; Spahr, H.; Hillmann, D.; König, P.; Hüttmann, G.

    2018-03-01

    Optical coherence tomography (OCT) images scattering tissues with 5 to 15 μm resolution. This is usually not sufficient for a distinction of cellular and subcellular structures. Increasing axial and lateral resolution and compensation of artifacts caused by dispersion and aberrations is required to achieve cellular and subcellular resolution. This includes defocus which limit the usable depth of field at high lateral resolution. OCT gives access the phase of the scattered light and hence correction of dispersion and aberrations is possible by numerical algorithms. Here we present a unified dispersion/aberration correction which is based on a polynomial parameterization of the phase error and an optimization of the image quality using Shannon's entropy. For validation, a supercontinuum light sources and a costume-made spectrometer with 400 nm bandwidth were combined with a high NA microscope objective in a setup for tissue and small animal imaging. Using this setup and computation corrections, volumetric imaging at 1.5 μm resolution is possible. Cellular and near cellular resolution is demonstrated in porcine cornea and the drosophila larva, when computational correction of dispersion and aberrations is used. Due to the excellent correction of the used microscope objective, defocus was the main contribution to the aberrations. In addition, higher aberrations caused by the sample itself were successfully corrected. Dispersion and aberrations are closely related artifacts in microscopic OCT imaging. Hence they can be corrected in the same way by optimization of the image quality. This way microscopic resolution is easily achieved in OCT imaging of static biological tissues.

  4. Optimum aberration coefficients for recording high-resolution off-axis holograms in a Cs-corrected TEM

    International Nuclear Information System (INIS)

    Linck, Martin

    2013-01-01

    Amongst the impressive improvements in high-resolution electron microscopy, the Cs-corrector also has significantly enhanced the capabilities of off-axis electron holography. Recently, it has been shown that the signal above noise in the reconstructable phase can be significantly improved by combining holography and hardware aberration correction. Additionally, with a spherical aberration close to zero, the traditional optimum focus for recording high-resolution holograms (“Lichte's defocus”) has become less stringent and both, defocus and spherical aberration, can be selected freely within a certain range. This new degree of freedom can be used to improve the signal resolution in the holographically reconstructed object wave locally, e.g. at the atomic positions. A brute force simulation study for an aberration corrected 200 kV TEM is performed to determine optimum values for defocus and spherical aberration for best possible signal to noise in the reconstructed atomic phase signals. Compared to the optimum aberrations for conventional phase contrast imaging (NCSI), which produce “bright atoms” in the image intensity, the resulting optimum values of defocus and spherical aberration for off-axis holography enable “black atom contrast” in the hologram. However, they can significantly enhance the local signal resolution at the atomic positions. At the same time, the benefits of hardware aberration correction for high-resolution off-axis holography are preserved. It turns out that the optimum is depending on the object and its thickness and therefore not universal. -- Highlights: ► Optimized aberration parameters for high-resolution off-axis holography. ► Simulation and analysis of noise in high-resolution off-axis holograms. ► Improving signal resolution in the holographically reconstructed phase shift. ► Comparison of “black” and “white” atom contrast in off-axis holograms.

  5. Prospects for versatile phase manipulation in the TEM: Beyond aberration correction

    International Nuclear Information System (INIS)

    Guzzinati, Giulio; Clark, Laura; Béché, Armand; Juchtmans, Roeland; Van Boxem, Ruben; Mazilu, Michael; Verbeeck, Jo

    2015-01-01

    In this paper we explore the desirability of a transmission electron microscope in which the phase of the electron wave can be freely controlled. We discuss different existing methods to manipulate the phase of the electron wave and their limitations. We show how with the help of current techniques the electron wave can already be crafted into specific classes of waves each having their own peculiar properties. Assuming a versatile phase modulation device is feasible, we explore possible benefits and methods that could come into existence borrowing from light optics where the so-called spatial light modulators provide programmable phase plates for quite some time now. We demonstrate that a fully controllable phase plate building on Harald Rose's legacy in aberration correction and electron optics in general would open an exciting field of research and applications. - Highlights: • We offer a review of available phase manipulation techniques. • We demonstrate a method for producing Airy waves through aberration manipulation. • We outline hypothetical applications of arbitrary phase manipulation methods

  6. High-resolution mass spectrometer with correction of horizontal and vertical aberrations

    International Nuclear Information System (INIS)

    Sachenko, V.D.; Fridlyanskij, G.V.

    1980-01-01

    Principles of calculation of the ion-optical system of a high-precision two-cascade sector type mass-spectrometer with total correction of spherical aberrations as well as the group of second order vertical aberrations are considered. A mass-spectrometer construction is described and some test results of the spectrometer are given. Configuration of boundaries of a spectrometer magnetic field has been formed by means of convex magnetic screens adjoining concave edqes of pole pieces. An energy diaphragm has been installed in the intermediate focus of the system. Precision slits of a source and receiver were made according to a spring parallelogram resolution of spectrometer constituted 80-100 thousands at a level of 10% of peak height. At a residual pressure of 5x10 -7 torr and 3-5x10 -5 torr inlet pressure in the source for Ar ''tail'' intensity in a neighbouring line amounted to 0.6x10 -6 of a main line. A measurement error for relative mass difference using the method of peak matching didnot exceed 1-2x10 -6

  7. TOPICAL REVIEW: Present status and future prospects of spherical aberration corrected TEM/STEM for study of nanomaterials

    Directory of Open Access Journals (Sweden)

    Nobuo Tanaka

    2008-01-01

    Full Text Available The present status of Cs-corrected TEM/STEM is described from the viewpoint of the observation of nanomaterials. Characteristic features in TEM and STEM are explained using the experimental data obtained by our group and other research groups. Cs correction up to the 3rd-order aberration of an objective lens has already been established and research interest is focused on correcting the 5th-order spherical aberration and the chromatic aberration in combination with the development of a monochromator below an electron gun for smaller point-to-point resolution in optics. Another fundamental area of interest is the limitation of TEM and STEM resolution from the viewpoint of the scattering of electrons in crystals. The minimum size of the exit-wave function below samples undergoing TEM imaging is determined from the calculation of scattering around related atomic columns in the crystals. STEM does not have this limitation because the resolution is, in principle, determined by the probe size. One of the future prospects of Cs-corrected TEM/STEM is the possibility of extending the space around the sample holder by correcting the chromatic and spherical aberrations. This wider space will contribute to the ease of performing in situ experiments and various combinations of TEM and other analysis methods. High-resolution, in situ dynamic and 3D observations/analysis are the most important keywords in the next decade of high-resolution electron microscopy.

  8. Space active optics: in flight aberrations correction for the next generation of large space telescopes

    Science.gov (United States)

    Laslandes, M.; Ferrari, M.; Hugot, E.; Lemaitre, G.

    2017-11-01

    The need for both high quality images and light structures is a constant concern in the conception of space telescopes. In this paper, we present an active optics system as a way to fulfill those two objectives. Indeed, active optics consists in controlling mirrors' deformations in order to improve the images quality [1]. The two main applications of active optics techniques are the in-situ compensation of phase errors in a wave front by using a corrector deformable mirror [2] and the manufacturing of aspherical mirrors by stress polishing or by in-situ stressing [3]. We will focus here on the wave-front correction. Indeed, the next generation of space telescopes will have lightweight primary mirrors; in consequence, they will be sensitive to the environment variations, inducing optical aberrations in the instrument. An active optics system is principally composed of a deformable mirror, a wave front sensor, a set of actuators deforming the mirror and control/command electronics. It is used to correct the wave-front errors due to the optical design, the manufacturing imperfections, the large lightweight primary mirrors' deflection in field gravity, the fixation devices, and the mirrors and structures' thermal distortions due to the local turbulence [4]. Active optics is based on the elasticity theory [5]; forces and/or load are used to deform a mirror. Like in adaptive optics, actuators can simply be placed under the optical surface [1,2], but other configurations have also been studied: a system's simplification, inducing a minimization of the number of actuators can be achieved by working on the mirror design [5]. For instance, in the so called Vase form Multimode Deformable Mirror [6], forces are applied on an external ring clamped on the pupil. With this method, there is no local effect due to the application of forces on the mirror's back face. Furthermore, the number of actuators needed to warp the mirror does not depend on the pupil size; it is a fully

  9. The first observation of titanate nanotubes by spherical aberration corrected high-resolution transmission electron microscopy

    Science.gov (United States)

    Miao, L.; Tanemura, S.; Jiang, T.; Tanemura, M.; Yoshida, K.; Tanaka, N.; Xu, G.

    2009-07-01

    Multi-wall titanate nanotubes (MW-TNNTs) with high aspect ratio, large surface area and good uniformity were produced by alkaline hydrothermal treatment of grounded TiO 2 aerogels and further by applying freeze-drying. Not only the crystal phase and diameter, but also morphology of the starting materials impact on the aspect ratio and transformation efficiency of the obtained nanotubes. Other parameters, such as pH value during neutralization process and drying method for the final products, are important to control length and dispersion of MW-TNNTs. By spherical aberration corrected high-resolution transmission-electron-microscopy (Cs-corrected HRTEM) with lateral space resolution of 0.14 nm at 200 kV accelerating voltage and electron energy loss spectrum (EELS), the detailed structural analysis of MW-TNNTs reveals that (1) diameters of inner and outer tubes are about 4-7 nm and 10 nm, respectively, (2) numbers of layers are different from part to part along the longitudinal tube axis, (3) the walls of the tubes have interlayer spacing of 0.70-0.80 nm and the lateral fringes which are vertical to the walls have spacing of 0.32 nm, (4) each layer of MW-TNNT is the nanosheet composed by the arrayed TiO 6 octahedrons, and respective octahedron being slightly strained, and (5) no chirality of MW-TNNT tubular structure is observed.

  10. High-resolution wide-field microscopy with adaptive optics for spherical aberration correction and motionless focusing.

    Science.gov (United States)

    Kner, P; Sedat, J W; Agard, D A; Kam, Z

    2010-02-01

    Live imaging in cell biology requires three-dimensional data acquisition with the best resolution and signal-to-noise ratio possible. Depth aberrations are a major source of image degradation in three-dimensional microscopy, causing a significant loss of resolution and intensity deep into the sample. These aberrations occur because of the mismatch between the sample refractive index and the immersion medium index. We have built a wide-field fluorescence microscope that incorporates a large-throw deformable mirror to simultaneously focus and correct for depth aberration in three-dimensional imaging. Imaging fluorescent beads in water and glycerol with an oil immersion lens we demonstrate a corrected point spread function and a 2-fold improvement in signal intensity. We apply this new microscope to imaging biological samples, and show sharper images and improved deconvolution.

  11. Modification of Deposited, Size-Selected MoS2 Nanoclusters by Sulphur Addition: An Aberration-Corrected STEM Study

    Directory of Open Access Journals (Sweden)

    Yubiao Niu

    2016-12-01

    Full Text Available Molybdenum disulphide (MoS2 is an earth-abundant material which has several industrial applications and is considered a candidate for platinum replacement in electrochemistry. Size-selected MoS2 nanoclusters were synthesised in the gas phase using a magnetron sputtering, gas condensation cluster beam source with a lateral time-of-flight mass selector. Most of the deposited MoS2 nanoclusters, analysed by an aberration-corrected scanning transmission electron microscope (STEM in high-angle annular dark field (HAADF mode, showed poorly ordered layer structures with an average diameter of 5.5 nm. By annealing and the addition of sulphur to the clusters (by sublimation in the cluster source, the clusters were transformed into larger, crystalline structures. Annealing alone did not lead to crystallization, only to a cluster size increase by decomposition and coalescence of the primary clusters. Sulphur addition alone led to a partially crystalline structure without a significant change in the size. Thus, both annealing and sulphur addition processes were needed to obtain highly crystalline MoS2 nanoclusters.

  12. Exploring the atomic structure of 1.8nm monolayer-protected gold clusters with aberration-corrected STEM.

    Science.gov (United States)

    Liu, Jian; Jian, Nan; Ornelas, Isabel; Pattison, Alexander J; Lahtinen, Tanja; Salorinne, Kirsi; Häkkinen, Hannu; Palmer, Richard E

    2017-05-01

    Monolayer-protected (MP) Au clusters present attractive quantum systems with a range of potential applications e.g. in catalysis. Knowledge of the atomic structure is needed to obtain a full understanding of their intriguing physical and chemical properties. Here we employed aberration-corrected scanning transmission electron microscopy (ac-STEM), combined with multislice simulations, to make a round-robin investigation of the atomic structure of chemically synthesised clusters with nominal composition Au 144 (SCH 2 CH 2 Ph) 60 provided by two different research groups. The MP Au clusters were "weighed" by the atom counting method, based on their integrated intensities in the high angle annular dark field (HAADF) regime and calibrated exponent of the Z dependence. For atomic structure analysis, we compared experimental images of hundreds of clusters, with atomic resolution, against a variety of structural models. Across the size range 123-151 atoms, only 3% of clusters matched the theoretically predicted Au 144 (SR) 60 structure, while a large proportion of the clusters were amorphous (i.e. did not match any model structure). However, a distinct ring-dot feature, characteristic of local icosahedral symmetry, was observed in about 20% of the clusters. Copyright © 2017. Published by Elsevier B.V.

  13. Prospective motion correction improves diagnostic utility of pediatric MRI scans

    Energy Technology Data Exchange (ETDEWEB)

    Kuperman, Joshua M.; Ahmadi, Mazyar E.; Erhart, Matthew J.; White, Nathan S.; Roddey, J.C. [University of California, San Diego, Multimodal Imaging Laboratory, La Jolla, CA (United States); University of California, San Diego, Department of Radiology, La Jolla, CA (United States); Brown, Timothy T. [University of California, San Diego, Multimodal Imaging Laboratory, La Jolla, CA (United States); Applied Science Laboratory, GE Healthcare, Rochester, MN (United States); Shankaranarayanan, Ajit; Han, Eric T. [Applied Science Laboratory, GE Healthcare, Menlo Park, CA (United States); Rettmann, Dan [University of California, San Diego, Department of Neurosciences, La Jolla, CA (United States); Dale, Anders M. [University of California, San Diego, Multimodal Imaging Laboratory, La Jolla, CA (United States); University of California, San Diego, Department of Radiology, La Jolla, CA (United States); Applied Science Laboratory, GE Healthcare, Rochester, MN (United States)

    2011-12-15

    A new technique for prospectively correcting head motion (called PROMO) during acquisition of high-resolution MRI scans has been developed to reduce motion artifacts. To evaluate the efficacy of PROMO, four T1-weighted image volumes (two with PROMO enabled, two uncorrected) were acquired for each of nine children. A radiologist, blind to whether PROMO was used, rated image quality and artifacts on all sagittal slices of every volume. These ratings were significantly better in scans collected with PROMO relative to those collected without PROMO (Mann-Whitney U test, P < 0.0001). The use of PROMO, especially in motion-prone patients, should improve the accuracy of measurements made for clinical care and research, and potentially reduce the need for sedation in children. (orig.)

  14. Prospective motion correction improves diagnostic utility of pediatric MRI scans

    International Nuclear Information System (INIS)

    Kuperman, Joshua M.; Ahmadi, Mazyar E.; Erhart, Matthew J.; White, Nathan S.; Roddey, J.C.; Brown, Timothy T.; Shankaranarayanan, Ajit; Han, Eric T.; Rettmann, Dan; Dale, Anders M.

    2011-01-01

    A new technique for prospectively correcting head motion (called PROMO) during acquisition of high-resolution MRI scans has been developed to reduce motion artifacts. To evaluate the efficacy of PROMO, four T1-weighted image volumes (two with PROMO enabled, two uncorrected) were acquired for each of nine children. A radiologist, blind to whether PROMO was used, rated image quality and artifacts on all sagittal slices of every volume. These ratings were significantly better in scans collected with PROMO relative to those collected without PROMO (Mann-Whitney U test, P < 0.0001). The use of PROMO, especially in motion-prone patients, should improve the accuracy of measurements made for clinical care and research, and potentially reduce the need for sedation in children. (orig.)

  15. Micro-scanning error correction technique for an optical micro-scanning thermal microscope imaging system

    Science.gov (United States)

    Gao, Mei-Jing; Tan, Ai-Ling; Yang, Ming; Xu, Jie; Zu, Zhen-Long; Wang, Jing-Yuan

    2018-01-01

    With optical micro-scanning technology, the spatial resolution of the thermal microscope imaging system can be increased without reducing the size of the detector unit or increasing the detector dimensions. Due to optical micro-scanning error, the four low-resolution images collected by micro-scanning thermal micro- scope imaging system are not standard down-sampled images. The reconstructed image quality is degraded by the direct image interpolation with error, which influences the performance of the system. Therefore, the technique to reduce the system micro-scanning error need to be studied. Based on micro-scanning technology and combined with new edge directed interpolation(NEDI) algorithm, an error correction technique for the micro-scanning instrument is proposed. Simulations and experiments show that the proposed technique can reduce the optical micro-scanning error, improve the imaging effect of the system and improve the systems spatial resolution. It can be applied to other electro-optical imaging systems to improve their resolution.

  16. Symmetrical optical imaging system with bionic variable-focus lens for off-axis aberration correction

    Science.gov (United States)

    Wang, Xuan-Yin; Du, Jia-Wei; Zhu, Shi-Qiang

    2017-09-01

    A bionic variable-focus lens with symmetrical layered structure was designed to mimic the crystalline lens. An optical imaging system based on this lens and with a symmetrical structure that mimics the human eye structure was proposed. The refractive index of the bionic variable-focus lens increases from outside to inside. The two PDMS lenses with a certain thickness were designed to improve the optical performance of the optical imaging system and minimise the gravity effect of liquid. The paper presents the overall structure of the optical imaging system and the detailed description of the bionic variable-focus lens. By pumping liquid in or out of the cavity, the surface curvatures of the rear PDMS lens were varied, resulting in a change in the focal length. The focal length range of the optical imaging system was 20.71-24.87 mm. The optical performance of the optical imaging system was evaluated by imaging experiments and analysed by ray tracing simulations. On the basis of test and simulation results, the optical performance of the system was quite satisfactory. Off-axis aberrations were well corrected, and the image quality was greatly improved.

  17. Double aberration-corrected TEM/STEM of tungstated zirconia nanocatalysts for the synthesis of paracetamol

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K; Boyes, E D; Gai, P L [York JEOL Nanocentre (United Kingdom); Shiju, N R; Brown, D R, E-mail: pgb500@york.ac.u [Department of Chemical and Biological Sciences, University of Huddersfield, Huddersfield, HD1 3DH (United Kingdom)

    2010-07-01

    We report highly active tungstated zirconia nanocatalysts for the synthesis of paracetamol by Beckmann rearrangement of 4-hydroxyacetophenone oxime. Double aberration-corrected (2AC)-TEM/STEM studies were performed in a JEOL 2200FS FEG TEM/STEM at the 1 Angstrom (1 A = 0.1 nanometer) level. Observations at close to zero defocus were carried out using the AC-TEM as well as AC-STEM including high angle annular dark field (HAADF) imaging, from the same areas of the catalyst crystallites. The studies from the same areas have revealed the location and the nanostructure of the polytungstate species (clusters) and the nanograins of zirconia. The AC (S)TEM was crucial to observe the nanostructure and location of polytungstate clusters on the zirconia grains. Polytungstate clusters as small as 0.5 nm have been identified using the HAADF-STEM. The nanostructures of the catalyst and the W surface density have been correlated with paracetamol reaction studies. The results demonstrate the nature of active sites and high activity of the tungstated zirconia nanocatalyst, which is an environmentally clean alternative to the current homogeneous process.

  18. Exploring the atomic structure of 1.8 nm monolayer-protected gold clusters with aberration-corrected STEM

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian; Jian, Nan; Ornelas, Isabel; Pattison, Alexander J. [Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Lahtinen, Tanja; Salorinne, Kirsi [Department of Chemistry, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä (Finland); Häkkinen, Hannu [Department of Chemistry, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä (Finland); Department of Physics, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä (Finland); Palmer, Richard E., E-mail: richardepalmerwork@yahoo.com [Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2017-05-15

    Monolayer-protected (MP) Au clusters present attractive quantum systems with a range of potential applications e.g. in catalysis. Knowledge of the atomic structure is needed to obtain a full understanding of their intriguing physical and chemical properties. Here we employed aberration-corrected scanning transmission electron microscopy (ac-STEM), combined with multislice simulations, to make a round-robin investigation of the atomic structure of chemically synthesised clusters with nominal composition Au{sub 144}(SCH{sub 2}CH{sub 2}Ph){sub 60} provided by two different research groups. The MP Au clusters were “weighed” by the atom counting method, based on their integrated intensities in the high angle annular dark field (HAADF) regime and calibrated exponent of the Z dependence. For atomic structure analysis, we compared experimental images of hundreds of clusters, with atomic resolution, against a variety of structural models. Across the size range 123–151 atoms, only 3% of clusters matched the theoretically predicted Au{sub 144}(SR){sub 60} structure, while a large proportion of the clusters were amorphous (i.e. did not match any model structure). However, a distinct ring-dot feature, characteristic of local icosahedral symmetry, was observed in about 20% of the clusters. - Highlights: • Chemically synthesised gold clusters were “weighed” by atom counting to get true size. • Image simulations show a few percent of clusters have the predicted atomic structure. • But a specific ring-dot feature indicates local icosahedral order in many clusters.

  19. Aberration corrected and monochromated environmental transmission electron microscopy: challenges and prospects for materials science

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal; Dunin-Borkowski, Rafal E.

    2010-01-01

    The latest generation of environmental transmission electron microscopes incorporates aberration correctors and monochromators, allowing studies of chemical reactions and growth processes with improved spatial resolution and spectral sensitivity. Here, we describe the performance of such an instr...

  20. The influence of C{sub s}/C{sub c} correction in analytical imaging and spectroscopy in scanning and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zaluzec, Nestor J., E-mail: zaluzec@microscopy.com

    2015-04-15

    Aberration correction in scanning/transmission electron microscopy (S/TEM) owes much to the efforts of a small dedicated group of innovators. Leading that frontier has been Prof. Harald Rose. To date his leadership and dynamic personality has spearheaded our ability to leave behind many of the limitations imposed by spherical aberration (C{sub s}) in high resolution phase contrast imaging. Following shortly behind, has been the development of chromatic aberration correction (C{sub c}) which augments those accomplishments. In this paper we will review and summarize how the combination of C{sub s}/C{sub c} technology enhances our ability to conduct hyperspectral imaging and spectroscopy in today's and future computationally mediated experiments in both thin as well as realistic specimens in vacuo and during in-situ/environmental experiments.

  1. Multiphoton fluorescence microscopy with GRIN objective aberration correction by low order adaptive optics.

    Science.gov (United States)

    Bortoletto, Favio; Bonoli, Carlotta; Panizzolo, Paolo; Ciubotaru, Catalin D; Mammano, Fabio

    2011-01-01

    Graded Index (GRIN) rod microlenses are increasingly employed in the assembly of optical probes for microendoscopy applications. Confocal, two-photon and optical coherence tomography (OCT) based on GRIN optical probes permit in-vivo imaging with penetration depths into tissue up to the centimeter range. However, insertion of the probe can be complicated by the need of several alignment and focusing mechanisms along the optical path. Furthermore, resolution values are generally not limited by diffraction, but rather by optical aberrations within the endoscope probe and feeding optics. Here we describe a multiphoton confocal fluorescence imaging system equipped with a compact objective that incorporates a GRIN probe and requires no adjustment mechanisms. We minimized the effects of aberrations with optical compensation provided by a low-order electrostatic membrane mirror (EMM) inserted in the optical path of the confocal architecture, resulting in greatly enhanced image quality.

  2. Interaction between single gold atom and the graphene edge: A study via aberration-corrected transmission electron microscopy

    KAUST Repository

    Wang, Hongtao

    2012-01-01

    Interaction between single noble metal atoms and graphene edges has been investigated via aberration-corrected and monochromated transmission electron microscopy. A collective motion of the Au atom and the nearby carbon atoms is observed in transition between energy-favorable configurations. Most trapping and detrapping processes are assisted by the dangling carbon atoms, which are more susceptible to knock-on displacements by electron irradiation. Thermal energy is lower than the activation barriers in transition among different energy-favorable configurations, which suggests electron-beam irradiation can be an efficient way of engineering the graphene edge with metal atoms. © 2012 The Royal Society of Chemistry.

  3. 3D printing of microlenses for aberration correction in GRIN microendoscopes

    KAUST Repository

    Antonini, Andrea

    2017-11-02

    Two-photon fluorescence microscopy provides high resolution information on the anatomy and function of cellular structures located several hundreds of microns deep within biological tissues. However, light scattering poses a fundamental limit to imaging of deeper areas (> 1.5 mm). Implantable microendoscopic probes based on graded index (GRIN) lenses are widely used tools to perform two-photon fluorescence microscopy in otherwise inaccessible regions[1], but the optical performances of with these probes are limited by intrinsic aberrations.

  4. The oblique effect has an optical component: orientation-specific contrast thresholds after correction of high-order aberrations.

    Science.gov (United States)

    Murray, Ian J; Elliott, Sarah L; Pallikaris, Aris; Werner, John S; Choi, Stacey; Tahir, Humza J

    2010-09-09

    Most of the high-order aberrations of the eye are not circularly symmetric. Hence, while it is well known that human vision is subject to cortically based orientation preference in cell tuning, the optics of the eye might also introduce some orientational anisotropy. We tested this idea by measuring contrast sensitivity at different orientations of sine-wave gratings when viewing through a closed-loop adaptive optics phoropter. Under aberration-corrected conditions, mean contrast sensitivity improved for all observers by a factor of 1.8× to 5×. The detectability of some orientations improved more than others. As expected, this orientation-specific effect varied between individuals. The sensitivity benefits were accurately predicted from MTF model simulations, demonstrating that the observed effects reflected the individual's pattern of high-order aberrations. In one observer, the orientation-specific effects were substantial: an improvement of 8× at one orientation and 2× in another orientation. The experiments confirm that, for conditions that are not diffraction limited, the optics of the eye introduce rotational asymmetry to the luminance distribution on the retina and that this impacts vision, inducing orientational anisotropy. These results suggest that the traditional view of meridional anisotropy having an entirely neural origin may be true for diffraction-limited pupils but that viewing through larger pupils introduces an additional orientation-specific optical component to this phenomenon.

  5. Online correction of scanning probe microscopes with pixel accuracy

    DEFF Research Database (Denmark)

    Dirscherl, Kai

    2000-01-01

    of 10 nm and an opening angle of 30.0 °. Even atomic resolution can be achieved. The scan movement of the tip is not linear however. This is caused by the propelling device of the SPM for the scan motion - a piezoelectric ceramic. The two major non-linear responses o f the piezo to the applied control......-20% depending on the piezo material used and the scan range. The change in sensitivity is up to 20% as well, depending on the scan frequency. Current software controlled SPM are equipped with an algorithm that changes the shape of the control voltage online in a way to produce a linear piezo movement...

  6. From Nanoparticles to Process An Aberration Corrected TEM Study of Fischer Tropsch Catalysts at Various Steps of the Process

    International Nuclear Information System (INIS)

    Braidy, N.; Blanchard, J.; Abatzoglou, N.; Andrei, C.

    2011-01-01

    χThe nanostructure of Fischer-Tropsch (FT) Fe carbides are investigated using aberration-corrected high-resolution transmission electron microscopy (TEM). The plasma-generated Fe carbides are analyzed just after synthesis, following reduction via a H2 treatment step and once used as FT catalyst and deactivated. The as-produced nanoparticles (NPs) are seen to be abundantly covered with graphitic and amorphous carbon. Using the extended information limit from the spherical aberration-corrected TEM, the NPs could be indexed as a mixture of NPs in the θ-Fe 3 C and χ-Fe 5 C 2 phases. The reduction treatment exposed the NPs by removing most of the carbonaceous speSubscript textcies while retaining the χ-Fe 5 C 2 . Fe-carbides NPs submitted to conditions typical to FT synthesis develop a Fe3O4 shell which eventually consumes the NPs up to a point where 3-4 nm residual carbide is left at the center of the particle. Subscript textVarious mechanisms explaining the formation of such a microstructure are discussed. (author)

  7. [Analysis of tongue color under natural daylight based on chromatic aberration correction].

    Science.gov (United States)

    Xu, Jia-tuo; Zhang, Zhi-feng; Yan, Zhu-juan; Tu, Li-ping; Lu, Lu-ming; Shi, Mei-yu; Zhu, Feng-lan

    2009-05-01

    To establish an analytical method for tongue image acquisition under natural daylight based on L*a*b* error correction, and to observe the classification rules of tongue color using color error correction. The tongue images in 413 cases were collected under natural indoor daylight by using Nikon D70 digital SLR camera, and then the color error was adjusted by using Nikon Capture NX software correction according to Kodak Q-13 grey card. The classification and quantitative analysis of the tongue color after software correction was carried out depending on L*a*b* color space. The software correction method had good effects in adjusting the tongue color image error. The L* values of light red, deep red and cyanosis tongues decreased as compared with that of light white tongue (PL*a*b* error correction is accurate in color restoration and feasible to operate.

  8. Method and system for automatically correcting aberrations of a beam of charged particles

    International Nuclear Information System (INIS)

    1975-01-01

    The location of a beam of charged particles within a deflection field is determined by its orthogonal deflection voltages. With the location of the beam in the field, correction currents are supplied to a focus coil and to each of a pair of stigmator coils to correct for change of focal length and astigmatism due to the beam being deflected away from the center of its deflection field

  9. Motion correction in optical coherence tomography volumes on a per A-scan basis using orthogonal scan patterns.

    Science.gov (United States)

    Kraus, Martin F; Potsaid, Benjamin; Mayer, Markus A; Bock, Ruediger; Baumann, Bernhard; Liu, Jonathan J; Hornegger, Joachim; Fujimoto, James G

    2012-06-01

    High speed Optical Coherence Tomography (OCT) has made it possible to rapidly capture densely sampled 3D volume data. One key application is the acquisition of high quality in vivo volumetric data sets of the human retina. Since the volume is acquired in a few seconds, eye movement during the scan process leads to distortion, which limits the accuracy of quantitative measurements using 3D OCT data. In this paper, we present a novel software based method to correct motion artifacts in OCT raster scans. Motion compensation is performed retrospectively using image registration algorithms on the OCT data sets themselves. Multiple, successively acquired volume scans with orthogonal fast scan directions are registered retrospectively in order to estimate and correct eye motion. Registration is performed by optimizing a large scale numerical problem as given by a global objective function using one dense displacement field for each input volume and special regularization based on the time structure of the acquisition process. After optimization, each volume is undistorted and a single merged volume is constructed that has superior signal quality compared to the input volumes. Experiments were performed using 3D OCT data from the macula and optic nerve head acquired with a high-speed ultra-high resolution 850 nm spectral OCT as well as wide field data acquired with a 1050 nm swept source OCT instrument. Evaluation of registration performance and result stability as well as visual inspection shows that the algorithm can correct for motion in all three dimensions and on a per A-scan basis. Corrected volumes do not show visible motion artifacts. In addition, merging multiple motion corrected and registered volumes leads to improved signal quality. These results demonstrate that motion correction and merging improves image quality and should also improve morphometric measurement accuracy from volumetric OCT data.

  10. Distributed scanning volumetric SDOCT for motion corrected corneal biometry.

    Science.gov (United States)

    McNabb, Ryan P; Larocca, Francesco; Farsiu, Sina; Kuo, Anthony N; Izatt, Joseph A

    2012-09-01

    We present a method, termed distributed scanning OCT (DSOCT), which reduces the effects of patient motion on corneal biometry utilizing current-generation clinically available spectral domain optical coherence tomography (SDOCT) systems. We first performed a pilot study of the power spectrum of normal patient axial eye motion based on repeated (M-mode) SDOCT. Using DSOCT to reduce the effects of patient motion, we conducted a preliminary patient study comparing the measured anterior and posterior corneal curvatures and the calculated corneal power to both corneal topography and Scheimpflug photography in normal subjects. The repeatability for the measured radius of curvature of both anterior and posterior surfaces as well as calculated corneal refractive power using DSOCT was comparable to those of both topography and Scheimpflug photography.

  11. Experimental demonstration of passive acoustic imaging in the human skull cavity using CT-based aberration corrections

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Ryan M., E-mail: rmjones@sri.utoronto.ca [Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario M4N 3M5, Canada and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7 (Canada); O’Reilly, Meaghan A. [Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario M4N 3M5 (Canada); Hynynen, Kullervo [Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario M4N 3M5 (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7 (Canada); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9 (Canada)

    2015-07-15

    Purpose: Experimentally verify a previously described technique for performing passive acoustic imaging through an intact human skull using noninvasive, computed tomography (CT)-based aberration corrections Jones et al. [Phys. Med. Biol. 58, 4981–5005 (2013)]. Methods: A sparse hemispherical receiver array (30 cm diameter) consisting of 128 piezoceramic discs (2.5 mm diameter, 612 kHz center frequency) was used to passively listen through ex vivo human skullcaps (n = 4) to acoustic emissions from a narrow-band fixed source (1 mm diameter, 516 kHz center frequency) and from ultrasound-stimulated (5 cycle bursts, 1 Hz pulse repetition frequency, estimated in situ peak negative pressure 0.11–0.33 MPa, 306 kHz driving frequency) Definity™ microbubbles flowing through a thin-walled tube phantom. Initial in vivo feasibility testing of the method was performed. The performance of the method was assessed through comparisons to images generated without skull corrections, with invasive source-based corrections, and with water-path control images. Results: For source locations at least 25 mm from the inner skull surface, the modified reconstruction algorithm successfully restored a single focus within the skull cavity at a location within 1.25 mm from the true position of the narrow-band source. The results obtained from imaging single bubbles are in good agreement with numerical simulations of point source emitters and the authors’ previous experimental measurements using source-based skull corrections O’Reilly et al. [IEEE Trans. Biomed. Eng. 61, 1285–1294 (2014)]. In a rat model, microbubble activity was mapped through an intact human skull at pressure levels below and above the threshold for focused ultrasound-induced blood–brain barrier opening. During bursts that led to coherent bubble activity, the location of maximum intensity in images generated with CT-based skull corrections was found to deviate by less than 1 mm, on average, from the position

  12. Atomic-resolution study of dislocation structures and interfaces in poly-crystalline thin film CdTe using aberration-corrected STEM

    Science.gov (United States)

    Paulauskas, Tadas; Colegrove, Eric; Buurma, Chris; Kim, Moon; Klie, Robert

    2014-03-01

    Commercial success of CdTe-based thin film photovoltaic devices stems from its nearly ideal direct band gap which very effectively couples to Sun's light spectrum as well as ease of manufacturing and low cost of these modules. However, to further improve the conversion efficiency beyond 20 percent, it is important to minimize the harmful effects of grain boundaries and lattice defects in CdTe. Direct atomic-scale characterization is needed in order identify the carrier recombination centers. Likewise, it is necessary to confirm that passivants in CdTe, such as Cl, are able to diffuse and bind to the target defects. In this study, we characterize dislocation structures and grain boundaries in poly-crystalline CdTe using aberration-corrected cold-field emission scanning transmission electron microscopy (STEM). The chemical composition of Shockley partial, Frank and Lomer-Cottrell dislocations is examined via atomic column-resolved X-ray energy dispersive (XEDS) and electron energy-loss spectroscopies (EELS). Segregation of Cl towards dislocation cores and grain boundaries is shown in CdCl2 treated samples. We also investigate interfaces in ultra-high-vacuum bonded CdTe bi-crystals with pre-defined misorientation angles which are intended to mimic grain boundaries. Funded by: DOE EERE Sunshot Award EE0005956.

  13. Lowered threshold energy for femtosecond laser induced optical breakdown in a water based eye model by aberration correction with adaptive optics.

    Science.gov (United States)

    Hansen, Anja; Géneaux, Romain; Günther, Axel; Krüger, Alexander; Ripken, Tammo

    2013-06-01

    In femtosecond laser ophthalmic surgery tissue dissection is achieved by photodisruption based on laser induced optical breakdown. In order to minimize collateral damage to the eye laser surgery systems should be optimized towards the lowest possible energy threshold for photodisruption. However, optical aberrations of the eye and the laser system distort the irradiance distribution from an ideal profile which causes a rise in breakdown threshold energy even if great care is taken to minimize the aberrations of the system during design and alignment. In this study we used a water chamber with an achromatic focusing lens and a scattering sample as eye model and determined breakdown threshold in single pulse plasma transmission loss measurements. Due to aberrations, the precise lower limit for breakdown threshold irradiance in water is still unknown. Here we show that the threshold energy can be substantially reduced when using adaptive optics to improve the irradiance distribution by spatial beam shaping. We found that for initial aberrations with a root-mean-square wave front error of only one third of the wavelength the threshold energy can still be reduced by a factor of three if the aberrations are corrected to the diffraction limit by adaptive optics. The transmitted pulse energy is reduced by 17% at twice the threshold. Furthermore, the gas bubble motions after breakdown for pulse trains at 5 kilohertz repetition rate show a more transverse direction in the corrected case compared to the more spherical distribution without correction. Our results demonstrate how both applied and transmitted pulse energy could be reduced during ophthalmic surgery when correcting for aberrations. As a consequence, the risk of retinal damage by transmitted energy and the extent of collateral damage to the focal volume could be minimized accordingly when using adaptive optics in fs-laser surgery.

  14. Error analysis of motion correction method for laser scanning of moving objects

    Science.gov (United States)

    Goel, S.; Lohani, B.

    2014-05-01

    The limitation of conventional laser scanning methods is that the objects being scanned should be static. The need of scanning moving objects has resulted in the development of new methods capable of generating correct 3D geometry of moving objects. Limited literature is available showing development of very few methods capable of catering to the problem of object motion during scanning. All the existing methods utilize their own models or sensors. Any studies on error modelling or analysis of any of the motion correction methods are found to be lacking in literature. In this paper, we develop the error budget and present the analysis of one such `motion correction' method. This method assumes availability of position and orientation information of the moving object which in general can be obtained by installing a POS system on board or by use of some tracking devices. It then uses this information along with laser scanner data to apply correction to laser data, thus resulting in correct geometry despite the object being mobile during scanning. The major application of this method lie in the shipping industry to scan ships either moving or parked in the sea and to scan other objects like hot air balloons or aerostats. It is to be noted that the other methods of "motion correction" explained in literature can not be applied to scan the objects mentioned here making the chosen method quite unique. This paper presents some interesting insights in to the functioning of "motion correction" method as well as a detailed account of the behavior and variation of the error due to different sensor components alone and in combination with each other. The analysis can be used to obtain insights in to optimal utilization of available components for achieving the best results.

  15. Correção das aberrações oculares nos retratamentos de LASIK personalizado e convencional Correction of ocular aberrations in custom and standard LASIK retreatments

    Directory of Open Access Journals (Sweden)

    Andréia Peltier Urbano

    2009-10-01

    Full Text Available OBJETIVO: Comparar a correção das aberrações oculares nos retratamentos de LASIK personalizado e convencional. MÉTODOS: Foi realizado um estudo prospectivo, randomizado, de 74 olhos de 37 pacientes submetidos ao retratamento de LASIK para correção de miopia e astigmatismo. Cada paciente foi submetido ao retratamento de LASIK personalizado Zyoptix (Bausch & Lomb em um olho e convencional Planoscan (Bausch & Lomb no olho contralateral. Foi comparada a correção das aberrações oculares nos retratamentos personalizado e convencional. RESULTADOS: No sexto mês pós-operatório, os olhos submetidos ao retratamento Zyoptix apresentaram diminuição estatisticamente significativa do defocus, astigmatismo, coma, aberração esférica, segunda ordem, terceira ordem, alta ordem e aberrações totais. Os olhos submetidos ao retratamento Planoscan apresentaram diminuição estatisticamente significativa do defocus, segunda ordem e aberrações totais. CONCLUSÕES: O retratamento personalizado foi superior ao retratamento convencional para a correção das aberrações oculares de baixa e alta ordens.PURPOSE: To compare the correction of ocular aberrations between custom and standard LASIK retreatment. METHODS: Prospective, randomized trial with paired eye control of 74 eyes from 37 patients who underwent LASIK retreatment. Each patient underwent retreatment using Zyoptix LASIK (Bausch & Lomb in 1 eye and Planoscan LASIK (Bausch & Lomb in the fellow eye. Correction of ocular aberrations was compared between custom and standard LASIK retreatments. RESULTS: At 6 months, there was a statistically significant reduction in defocus, astigmatism, coma, spherical aberration, second, third, higher-order and total aberration in Zyoptix eyes. There was a statistically significant reduction in defocus, second-order and total aberration in Planoscan eyes. CONCLUSIONS: Custom retreatment was statistically superior than standard retreatment for correction of lower

  16. Wavefront correction for static and dynamic aberrations to within 1 second of the system shot in the NIF Beamlet demonstration facility

    International Nuclear Information System (INIS)

    Hartley, R.; Kartz, M.; Behrendt, W.

    1996-10-01

    The laser wavefront of the NIF Beamlet demonstration system is corrected for static aberrations with a wavefront control system. The system operates closed loop with a probe beam prior to a shot and has a loop bandwidth of about 3 Hz. However, until recently the wavefront control system was disabled several minutes prior to the shot to allow time to manually reconfigure its attenuators and probe beam insertion mechanism to shot mode. Thermally-induced dynamic variations in gas density in the Beamlet main beam line produce significant wavefront error. After about 5-8 seconds, the wavefront error has increased to a new, higher level due to turbulence- induced aberrations no longer being corrected- This implies that there is a turbulence-induced aberration noise bandwidth of less than one Hertz, and that the wavefront controller could correct for the majority of turbulence-induced aberration (about one- third wave) by automating its reconfiguration to occur within one second of the shot, This modification was recently implemented on Beamlet; we call this modification the t 0 -1 system

  17. Double-aberration corrected TEM/STEM of solid acid nanocatalysts in the development of pharmaceutical NSAIDS

    Science.gov (United States)

    Yoshida, K.; Shiju, N.; Brown, R.; Wright, I.; Boyes, E. D.; Gai, P. L.

    2012-07-01

    We report nanostructural and physico-chemical studies in the development of an efficient low temperature heterogeneous catalytic process for nonsteroidal anti-inflammatory drugs (NSAIDS) such as N-acetyl-p-aminophenol (paracetamol or acetaminophen) on tungstated zirconia nanocatalysts. Using a double-aberration corrected TEM/STEM, modified in-house for in-situ studies at the sub-Angstrom level, we directly observed in real-time, the dynamic precursor transformation to the active catalyst. We quantified the observations with catalytic activity studies for the NSAIDS. The studies have provided the direct evidence for single tungsten promoter atoms and surface WOx species of <= 0.35 nm, with nanoclusters of WOx (0.6 to 1nm), located at grain boundaries on the surface of the zirconia nanoparticles. The correlation between the nanostructure and catalytic activity indicates that the species create Brønsted acid sites highly active for the low temperature process. The results open up opportunities for developing green heterogeneous methods for pharmaceuticals.

  18. Atomic resolution imaging of YAlO{sub 3}: Ce in the chromatic and spherical aberration corrected PICO electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Lei [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Barthel, Juri [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Central Facility for Electron Microscopy, RWTH Aachen University, 52074 Aachen (Germany); Jia, Chun-Lin [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); School of Electronic and Information Engineering and State Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Urban, Knut W., E-mail: k.urban@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich GmbH, 52425 Jülich, (Germany); School of Electronic and Information Engineering and State Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2017-05-15

    Highlights: • First time resolution of 57 pm atom separations by HRTEM with 200 keV electrons. • Quantification of the image spread by absolute matching of experiment and simulation. • An information limit of 52 pm is deduced from the determined image spread. • Substantial deviations from the bulk structure are observed for the ultra-thin sample. - Abstract: The application of combined chromatic and spherical aberration correction in high-resolution transmission electron microscopy enables a significant improvement of the spatial resolution down to 50 pm. We demonstrate that such a resolution can be achieved in practice at 200 kV. Diffractograms of images of gold nanoparticles on amorphous carbon demonstrate corresponding information transfer. The Y atom pairs in [010] oriented yttrium orthoaluminate are successfully imaged together with the Al and the O atoms. Although the 57 pm pair separation is well demonstrated separations between 55 pm and 80 pm are measured. This observation is tentatively attributed to structural relaxations and surface reconstruction in the very thin samples used. Quantification of the resolution limiting effective image spread is achieved based on an absolute match between experimental and simulated image intensity distributions.

  19. Aberration corrected and 3D cryo-tomography HAADF-STEM surface studies of ZnO tetrapods

    International Nuclear Information System (INIS)

    Ward, M R; Gai, P L; Boyes, E D; Sugiura, H; Tanaka, N; Yoshida, K

    2012-01-01

    We present a morphology study of ZnO tetrapods using aberration corrected TEM, HAADF-STEM and 3D HAADF-STEM cryotomography as an alternative to more conventional TEM and SEM techniques. We use 3D IMOD reconstructions to show that the {11-bar 0} facets dominate the total surface area of uniform hexagonal prism tetrapods. Using HRTEM we show that the small tetrapods have a zincblende phase core from which the four legs extend. The facets and the edges of these legs were found to be atomically clean and flat with the potential for ZnO tetrapods as model substrates. We deposited ultrafine Pt/Pd nanoparticles onto the tetrapods and investigated the resulting morphologies. We found using HAADF-STEM cryotomography and reconstruction techniques that the nanoparticle coverage gave separate nanoparticles and overall uniform coverage. We believe these techniques and the results from them could be useful for the development of nanoparticle-ZnO tetrapod composite systems with applications in optoelectronics, gas sensing and catalysis.

  20. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2017-05-15

    Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

  1. Attainment of 40.5 pm spatial resolution using 300 kV scanning transmission electron microscope equipped with fifth-order aberration corrector.

    Science.gov (United States)

    Morishita, Shigeyuki; Ishikawa, Ryo; Kohno, Yuji; Sawada, Hidetaka; Shibata, Naoya; Ikuhara, Yuichi

    2018-02-01

    The achievement of a fine electron probe for high-resolution imaging in scanning transmission electron microscopy requires technological developments, especially in electron optics. For this purpose, we developed a microscope with a fifth-order aberration corrector that operates at 300 kV. The contrast flat region in an experimental Ronchigram, which indicates the aberration-free angle, was expanded to 70 mrad. By using a probe with convergence angle of 40 mrad in the scanning transmission electron microscope at 300 kV, we attained the spatial resolution of 40.5 pm, which is the projected interatomic distance between Ga-Ga atomic columns of GaN observed along [212] direction.

  2. On the Frequency Correction in Temperature-Modulated Differential Scanning Calorimetry of Glass Transition

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, J.C.; Allan, D.C.

    2012-01-01

    Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG® glass over a wide range of modulation frequencies. Our results reveal that the frequen...... correction. The resulting glass transition temperature from the frequency corrected reversing heat flow is thereby shown to be independent of frequency.......Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG® glass over a wide range of modulation frequencies. Our results reveal that the frequency...

  3. Improving imaging of the air-liquid interface in living mice by aberration-corrected optical coherence tomography (mOCT) (Conference Presentation)

    Science.gov (United States)

    Schulz-Hildebrandt, Hinnerk; Sauer, Benjamin; Reinholz, Fred; Pieper, Mario; Mall, Markus; König, Peter; Huettmann, Gereon

    2017-04-01

    Failure in mucociliary clearance is responsible for severe diseases like cystic fibroses, primary ciliary dyskinesia or asthma. Visualizing the mucous transport in-vivo will help to understanding transport mechanisms as well as developing and validating new therapeutic intervention. However, in-vivo imaging is complicated by the need of high spatial and temporal resolution. Recently, we developed microscopy optical coherence tomography (mOCT) for non-invasive imaging of the liquid-air interface in intact murine trachea from its outside. Whereas axial resolution of 1.5 µm is achieved by the spectral width of supercontinuum light source, lateral resolution is limited by aberrations caused by the cylindric shape of the trachea and optical inhomogenities of the tissue. Therefore, we extended our mOCT by a deformable mirror for compensation of the probe induced aberrations. Instead of using a wavefront sensor for measuring aberrations, we harnessed optimization of the image quality to determine the correction parameter. With the aberration corrected mOCT ciliary function and mucus transport was measured in wild type and βENaC overexpressing mice, which served as a model for cystic fibrosis.

  4. 3D scanning based mold correction for planar and cylindrical parts in aluminum die casting

    Directory of Open Access Journals (Sweden)

    Takashi Seno

    2015-04-01

    Full Text Available Aluminum die casting is an important manufacturing process for mechanical components. Die casting is known to be more accurate than other types of casting; however, post-machining is usually necessary to achieve the required accuracy. The goal of this investigation is to develop machining- free aluminum die casting. Improvement of the accuracy of planar and cylindrical parts is expected by correcting metal molds. In the proposed method, the shape of cast aluminum made with the initial metal molds is measured by 3D scanning. The 3D scan data includes information about deformations that occur during casting. Therefore, it is possible to estimate the deformation and correction amounts by comparing 3D scan data with product computer-aided design (CAD data. We corrected planar and cylindrical parts of the CAD data for the mold. In addition, we corrected the planar part of the metal mold using the corrected mold data. The effectiveness of the proposed method is demonstrated by evaluating the accuracy improvement of the cast aluminum made with the corrected mold.

  5. Improvement of laser dicing performance II: dicing rate enhancement by multi beams and simultaneous aberration correction with phase-only spatial light modulator

    Science.gov (United States)

    Takiguchi, Yu; Matsumoto, Naoya; Oyaizu, Masaki; Okuma, Jyunji; Nakano, Makoto; Sakamoto, Takeshi; Itoh, Haruyasu; Inoue, Takashi

    2013-03-01

    "Stealth Dicing" laser processing is a dry and debris-free semiconductor wafer dicing method achieved by generating thermal micro-cracks inside a wafer with a tightly focused laser beam. This method has two practical issues: (1) the dicing speed is limited by the repetition rate of the pulsed laser, and (2) integrated circuits on the opposite side of the wafer from the laser light are potentially damaged by excessive laser intensity required to compensate for insufficient beam convergence. The insufficient beam convergence is a result of spherical aberration due to a refractive index mismatch between air and the wafer. These problems can be resolved by incorporating a phase-only spatial light modulator (SLM) into the laser dicing system. The SLM produces two types of wavefront configurations simultaneously for two different functions. One is for multi-beam generation with a phase grating pattern. This improves the dicing speed by a factor equal to the number of diffracted beams. The other is for aberration correction of the multiple beams using a pre-distorted wavefront pattern. By correcting aberrations, the focused multiple beams inside the wafer will become sufficiently convergent to avoid undesirable laser damage. We demonstrated these improvements by dicing sapphire wafers with a pulsed laser and a high-numerical-aperture objective lens.

  6. Corrections of Magnification and Focusing in a Cathode Lens-Equipped Scanning Electron Microscope

    Czech Academy of Sciences Publication Activity Database

    Zobačová, Jitka; Zobač, Martin; Oral, Martin; Müllerová, Ilona; Frank, Luděk

    2006-01-01

    Roč. 28, č. 3 (2006), s. 155-163 ISSN 0161-0457 R&D Projects: GA AV ČR KJB2065301 Institutional research plan: CEZ:AV0Z20650511 Keywords : low-energy scanning electron microscopy (SEM) * cathode lens * critical dimension measurement in SEM * automatic corrections Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.462, year: 2006

  7. Real-time scanning charged-particle microscope image composition with correction of drift.

    Science.gov (United States)

    Cizmar, Petr; Vladár, András E; Postek, Michael T

    2011-04-01

    In this article, a new scanning electron microscopy (SEM) image composition technique is described, which can significantly reduce drift related image corruptions. Drift distortion commonly causes blur and distortions in the SEM images. Such corruption ordinarily appears when conventional image-acquisition methods, i.e., "slow scan" and "fast scan," are applied. The damage is often very significant; it may render images unusable for metrology applications, especially where subnanometer accuracy is required. The described correction technique works with a large number of quickly taken frames, which are properly aligned and then composed into a single image. Such image contains much less noise than the individual frames, while the blur and deformation is minimized. This technique also provides useful information about changes of the sample position in time, which may be applied to investigate the drift properties of the instrument without a need of additional equipment.

  8. Terrestrial Laser Scanning Intensity Correction by Piecewise Fitting and Overlap-Driven Adjustment

    Directory of Open Access Journals (Sweden)

    Teng Xu

    2017-10-01

    Full Text Available Terrestrial laser scanning sensors deliver not only three-dimensional geometric information of the scanned objects but also the intensity data of returned laser pulse. Recent studies have demonstrated potential applications of intensity data from Terrestrial Laser Scanning (TLS. However, the distance and incident angle effects distort the TLS raw intensity data. To overcome the distortions, a new intensity correction method by combining the piecewise fitting and overlap-driven adjustment approaches was proposed in this study. The distance effect is eliminated by the piecewise fitting approach. The incident angle effect is eliminated by overlap-driven adjustment using the Oren–Nayar model that employs the surface roughness parameter of the scanned object. The surface roughness parameter at a certain point in an overlapped region of the multi-station scans is estimated by using the raw intensity data from two different stations at the point rather than estimated by averaging the surface roughness at other positions for each kind of object, which eliminates the estimation deviation. Experimental results obtained by using a TLS sensor (Riegl VZ-400i demonstrate that the proposed method is valid and the deviations of the retrieved reflectance values from those measured by a spectrometer are all less than 3%.

  9. Optical Design of Adaptive Optics Confocal Scanning Laser Ophthalmoscope with Two Deformable Mirrors.

    Science.gov (United States)

    Yang, Jinsheng; Wang, Yuanyuan; Rao, Xuejun; Wei, Ling; Li, Xiqi; He, Yi

    2017-01-01

    We describe the optical design of a confocal scanning laser ophthalmoscope with two deformable mirrors. Spherical mirrors are used for pupil relay. Defocus aberration of the human eye is corrected by a Badal focusing structure and astigmatism aberration is corrected by a deformable mirror. The main optical system achieves a diffraction-limited performance through the entire scanning field (6 mm pupil, 3 degrees on pupil plane). The performance of the optical system, with correction of defocus and astigmatism, is also evaluated.

  10. Correction of image distortions in endoscopic optical coherence tomography based on two-axis scanning MEMS mirrors

    Science.gov (United States)

    Wang, Donglin; Liang, Peng; Samuelson, Sean; Jia, Hongzhi; Ma, Junshan; Xie, Huikai

    2013-01-01

    A two-axis scanning microelectromechanical (MEMS) mirror enables an optical coherence tomography (OCT) system to perform three-dimensional endoscopic imaging due to its fast scan speed and small size. However, the radial scan from the MEMS mirror causes various distortions in OCT images, namely spherical, fan-shaped and keystone distortions. In this paper, a new method is proposed to correct all of three distortions presented in OCT systems based on two-axis MEMS scanning mirrors. The spherical distortion is corrected first by directly manipulating the original spectral interferograms in the phase domain, followed by Fourier transform and three-dimensional geometrical transformation for correcting the other two types of distortions. OCT imaging experiments on a paper with square ink printed arrays and a glass tube filled with milk have been used to validate the proposed method. Distortions in OCT images of flat or curved surfaces can all be effectively removed. PMID:24156064

  11. The Aberrant Coronary Artery - The Management Approach.

    Science.gov (United States)

    King, Nina-Marie; Tian, David D; Munkholm-Larsen, Stine; Buttar, Sana N; Chow, Vincent; Yan, Tristan

    2017-07-03

    An aberrant coronary artery is a rare clinical occurrence with an incidence of 0.05-1.2%. Often it is an incidental finding detected on coronary angiography or at autopsy. However, symptomatic patients can experience angina, arrhythmia, sudden death or non-specific symptoms such as dyspnoea and syncope. At present, there are no guidelines or dedicated studies assessing the treatment of an aberrant coronary artery leaving management options for these patients controversial. Selected international cardiothoracic surgeons were surveyed electronically in November 2016 to determine whether consensus exists on different management aspects for patients with an aberrant coronary artery arising from the contralateral sinus with an interarterial course. For asymptomatic patients with either an aberrant left main coronary artery (ALMCA) arising from the contralateral sinus or an aberrant right main coronary artery (ARMCA) arising from the contralateral sinus, there was no consensus on surgical correction of the anomaly. If myocardial ischaemia was demonstrated on either coronary angiography with fractional flow reserve measurements and/or stress myocardial perfusion scan, surgical correction was the consensus between the surveyed surgeons. If surgery was deemed appropriate, coronary artery bypass surgery utilising the internal mammary artery was marginally preferred by the respondents in patients with an ALMCA whilst unroofing of the coronary ostium was preferred in patients with an ARMCA. Although no consensus was reached, a large proportion of respondents would not treat a patient over the age of 30 years differently compared to those under 30 years old. For symptomatic patients or if myocardial ischaemia is demonstrated on either coronary angiography with fractional flow reserve measurements and/or stress myocardial perfusion scan, surgical correction is indicated. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the

  12. A New Radiometric Correction Method for Side-Scan Sonar Images in Consideration of Seabed Sediment Variation

    Directory of Open Access Journals (Sweden)

    Jianhu Zhao

    2017-06-01

    Full Text Available Affected by the residual of time varying gain, beam patterns, angular responses, and sonar altitude variations, radiometric distortion degrades the quality of side-scan sonar images and seriously affects the application of these images. However, existing methods cannot correct distortion effectively, especially in the presence of seabed sediment variation. This study proposes a new radiometric correction method for side-scan sonar images that considers seabed sediment variation. First, the different effects on backscatter strength (BS are analyzed, and along-track distortion is removed by establishing a linear relationship between distortion and sonar altitude. Second, because the angle-related effects on BSs with the same incident angle are the same, a novel method of unsupervised sediment classification is proposed for side-scan sonar images. Finally, the angle–BS curves of different sediments are obtained, and angle-related radiometric distortion is corrected. Experiments prove the validity of the proposed method.

  13. Wide aperture multipole magnets of the kinematic separator COMBAS. Correcting pair of multipole magnets M3M4 (M5M6) with compensation for higher order aberrations

    International Nuclear Information System (INIS)

    Artyukh, A.G.; Gridnev, G.F.; Teterev, Yu.G.

    1999-01-01

    The high-resolving large aperture separator COMBAS has been created and commissioned. The magneto-optical structure of the separator is based on the strong focusing principle. The separator consists of eight wide aperture multipole magnets M1-M8. The magnets M1, M2, M7, M8 forming the 1 st order optics together with some higher order optical corrections and M3-M6 being dedicated to higher order corrections of the chromatic and spherical aberrations at the intermediate and exit foci of the separator. The multipole correctors M3-M6 contain the dipolar, sextupole and octupole components in their magnetic field distributions. It was the use of the rectangular dipoles M3-M6 as carriers of sextupole and octupole field components that let achieve high values of the separator angular and momentum acceptances. Measurements of the magnetic field distributions in the median planes of the pairs of magnets M3M6 (M4M5) have been performed. These measurements allowed one to analyze the magnets manufacturing quality. Based on the analysis, shimming of pole pieces of the pair of magnets M3M6 have been done. Pole surface correcting coils for the magnets M4M5 have been foreseen to compensate for small deviations (within a few percents) of the 2 nd and 3 rd order field components from the design values, which are probable due to manufacturing errors in all the magnets M1-M8. The measured magnetic field distributions are supposed to be used for particle trajectory simulations throughout the entire separator

  14. Chromosomal aberration

    International Nuclear Information System (INIS)

    Ishii, Yutaka

    1988-01-01

    Chromosomal aberrations are classified into two types, chromosome-type and chromatid-type. Chromosom-type aberrations include terminal deletion, dicentric, ring and interstitial deletion, and chromatid-type aberrations include achromatic lesion, chromatid deletion, isochromatid deletion and chromatid exchange. Clastogens which induce chromosomal aberration are divided into ''S-dependent'' agents and ''S-independent''. It might mean whether they can induce double strand breaks independent of the S phase or not. Double strand breaks may be the ultimate lesions to induce chromosomal aberrations. Caffeine added even in the G 2 phase appeared to modify the frequency of chromatid aberrations induced by X-rays and mitomycin C. Those might suggest that the G 2 phase involves in the chromatid aberration formation. The double strand breaks might be repaired by ''G 2 repair system'', the error of which might yield breakage types of chromatid aberrations and the by-pass of which might yield chromatid exchanges. Chromosome-type aberrations might be formed in the G 1 phase. (author)

  15. Evaluation of stacking faults and associated partial dislocations in AlSb/GaAs (001 interface by aberration-corrected high-resolution transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    C. Wen

    2014-11-01

    Full Text Available The stacking faults (SFs in an AlSb/GaAs (001 interface were investigated using a 300 kV spherical aberration-corrected high-resolution transmission electron microscope (HRTEM. The structure and strain distribution of the single and intersecting (V-shaped SFs associated with partial dislocations (PDs were characterized by the [110] HRTEM images and geometric phase analysis, respectively. In the biaxial strain maps εxx and εyy, a SF can be divided into several sections under different strain states (positive or negative strain values. Furthermore, the strain state for the same section of a SF is in contrast to each other in εxx and εyy strain maps. The modification in the strain states was attributed to the variation in the local atomic displacements for the SF in the AlSb film on the GaAs substrate recorded in the lattice image. Finally, the single SF was found to be bounded by two 30° PDs. A pair of 30° PDs near the heteroepitaxial interface reacted to form a Lomer-Cottrell sessile dislocation located at the vertices of V-shaped SFs with opposite screw components. The roles of misfit dislocations, such as the PDs, in strain relaxation were also discussed.

  16. Evaluation of stacking faults and associated partial dislocations in AlSb/GaAs (001) interface by aberration-corrected high-resolution transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wen, C., E-mail: wencai@swust.edu.cn [School of Science, Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010 (China); Ge, B. H.; Cui, Y. X.; Li, F. H. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zhu, J.; Yu, R.; Cheng, Z. Y. [Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-11-15

    The stacking faults (SFs) in an AlSb/GaAs (001) interface were investigated using a 300 kV spherical aberration-corrected high-resolution transmission electron microscope (HRTEM). The structure and strain distribution of the single and intersecting (V-shaped) SFs associated with partial dislocations (PDs) were characterized by the [110] HRTEM images and geometric phase analysis, respectively. In the biaxial strain maps ε{sub xx} and ε{sub yy}, a SF can be divided into several sections under different strain states (positive or negative strain values). Furthermore, the strain state for the same section of a SF is in contrast to each other in ε{sub xx} and ε{sub yy} strain maps. The modification in the strain states was attributed to the variation in the local atomic displacements for the SF in the AlSb film on the GaAs substrate recorded in the lattice image. Finally, the single SF was found to be bounded by two 30° PDs. A pair of 30° PDs near the heteroepitaxial interface reacted to form a Lomer-Cottrell sessile dislocation located at the vertices of V-shaped SFs with opposite screw components. The roles of misfit dislocations, such as the PDs, in strain relaxation were also discussed.

  17. Fast Focal Point Correction in Prism-Coupled Total Internal Reflection Scanning Imager Using an Electronically Tunable Lens.

    Science.gov (United States)

    Zhu, Chenggang; Ge, Bilin; Chen, Ru; Zhu, Xiangdong; Mi, Lan; Ma, Jiong; Wang, Xu; Zheng, Fengyun; Fei, Yiyan

    2018-02-09

    Total internal reflection (TIR) is useful for interrogating physical and chemical processes that occur at the interface between two transparent media. Yet prism-coupled TIR imaging microscopes suffer from limited sensing areas due to the fact that the interface (the object plane) is not perpendicular to the optical axis of the microscope. In this paper, we show that an electrically tunable lens can be used to rapidly and reproducibly correct the focal length of an oblique-incidence scanning microscope (OI-RD) in a prism-coupled TIR geometry. We demonstrate the performance of such a correction by acquiring an image of a protein microarray over a scan area of 4 cm² with an effective resolution of less than 20 microns. The electronic focal length tuning eliminates the mechanical movement of the illumination lens in the scanning microscope and in turn the noise and background drift associated with the motion.

  18. Fast Focal Point Correction in Prism-Coupled Total Internal Reflection Scanning Imager Using an Electronically Tunable Lens

    Directory of Open Access Journals (Sweden)

    Chenggang Zhu

    2018-02-01

    Full Text Available Total internal reflection (TIR is useful for interrogating physical and chemical processes that occur at the interface between two transparent media. Yet prism-coupled TIR imaging microscopes suffer from limited sensing areas due to the fact that the interface (the object plane is not perpendicular to the optical axis of the microscope. In this paper, we show that an electrically tunable lens can be used to rapidly and reproducibly correct the focal length of an oblique-incidence scanning microscope (OI-RD in a prism-coupled TIR geometry. We demonstrate the performance of such a correction by acquiring an image of a protein microarray over a scan area of 4 cm2 with an effective resolution of less than 20 microns. The electronic focal length tuning eliminates the mechanical movement of the illumination lens in the scanning microscope and in turn the noise and background drift associated with the motion.

  19. Spherical aberration in contact lens wear.

    Science.gov (United States)

    Lindskoog Pettersson, A; Jarkö, C; Alvin, A; Unsbo, P; Brautaset, R

    2008-08-01

    The aim of the present studies was to investigate the effect on spherical aberration of different non custom-made contact lenses, both with and without aberration control. A wavefront analyser (Zywave, Bausch & Lomb) was used to measure the aberrations in each subject's right eye uncorrected and with the different contact lenses. The first study evaluated residual spherical aberration with a standard lens (Focus Dailies Disposable, Ciba Vision) and with an aberration controlled contact lens (ACCL) (Definition AC, Optical Connection Inc.). The second study evaluated the residual spherical aberrations with a monthly disposable silicone hydrogel lens with aberration reduction (PureVision, Bausch & Lomb). Uncorrected spherical aberration was positive for all pupil sizes in both studies. In the first study, residual spherical aberration was close to zero with the standard lens for all pupil sizes whereas the ACCL over-corrected spherical aberration. The results of the second study showed that the monthly disposable lens also over-corrected the aberration making it negative. The changes in aberration were statistically significant (plenses. Since the amount of aberration varies individually we suggest that aberrations should be measured with lenses on the eye if the aim is to change spherical aberration in a certain direction.

  20. Analytic image reconstruction from partial data for a single-scan cone-beam CT with scatter correction

    Energy Technology Data Exchange (ETDEWEB)

    Min, Jonghwan; Pua, Rizza; Cho, Seungryong, E-mail: scho@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Insoo; Han, Bumsoo [EB Tech, Co., Ltd., 550 Yongsan-dong, Yuseong-gu, Daejeon 305-500 (Korea, Republic of)

    2015-11-15

    Purpose: A beam-blocker composed of multiple strips is a useful gadget for scatter correction and/or for dose reduction in cone-beam CT (CBCT). However, the use of such a beam-blocker would yield cone-beam data that can be challenging for accurate image reconstruction from a single scan in the filtered-backprojection framework. The focus of the work was to develop an analytic image reconstruction method for CBCT that can be directly applied to partially blocked cone-beam data in conjunction with the scatter correction. Methods: The authors developed a rebinned backprojection-filteration (BPF) algorithm for reconstructing images from the partially blocked cone-beam data in a circular scan. The authors also proposed a beam-blocking geometry considering data redundancy such that an efficient scatter estimate can be acquired and sufficient data for BPF image reconstruction can be secured at the same time from a single scan without using any blocker motion. Additionally, scatter correction method and noise reduction scheme have been developed. The authors have performed both simulation and experimental studies to validate the rebinned BPF algorithm for image reconstruction from partially blocked cone-beam data. Quantitative evaluations of the reconstructed image quality were performed in the experimental studies. Results: The simulation study revealed that the developed reconstruction algorithm successfully reconstructs the images from the partial cone-beam data. In the experimental study, the proposed method effectively corrected for the scatter in each projection and reconstructed scatter-corrected images from a single scan. Reduction of cupping artifacts and an enhancement of the image contrast have been demonstrated. The image contrast has increased by a factor of about 2, and the image accuracy in terms of root-mean-square-error with respect to the fan-beam CT image has increased by more than 30%. Conclusions: The authors have successfully demonstrated that the

  1. Analytic image reconstruction from partial data for a single-scan cone-beam CT with scatter correction.

    Science.gov (United States)

    Min, Jonghwan; Pua, Rizza; Kim, Insoo; Han, Bumsoo; Cho, Seungryong

    2015-11-01

    A beam-blocker composed of multiple strips is a useful gadget for scatter correction and/or for dose reduction in cone-beam CT (CBCT). However, the use of such a beam-blocker would yield cone-beam data that can be challenging for accurate image reconstruction from a single scan in the filtered-backprojection framework. The focus of the work was to develop an analytic image reconstruction method for CBCT that can be directly applied to partially blocked cone-beam data in conjunction with the scatter correction. The authors developed a rebinned backprojection-filteration (BPF) algorithm for reconstructing images from the partially blocked cone-beam data in a circular scan. The authors also proposed a beam-blocking geometry considering data redundancy such that an efficient scatter estimate can be acquired and sufficient data for BPF image reconstruction can be secured at the same time from a single scan without using any blocker motion. Additionally, scatter correction method and noise reduction scheme have been developed. The authors have performed both simulation and experimental studies to validate the rebinned BPF algorithm for image reconstruction from partially blocked cone-beam data. Quantitative evaluations of the reconstructed image quality were performed in the experimental studies. The simulation study revealed that the developed reconstruction algorithm successfully reconstructs the images from the partial cone-beam data. In the experimental study, the proposed method effectively corrected for the scatter in each projection and reconstructed scatter-corrected images from a single scan. Reduction of cupping artifacts and an enhancement of the image contrast have been demonstrated. The image contrast has increased by a factor of about 2, and the image accuracy in terms of root-mean-square-error with respect to the fan-beam CT image has increased by more than 30%. The authors have successfully demonstrated that the proposed scanning method and image

  2. SU-E-T-464: On the Equivalence of the Quality Correction Factor for Pencil Beam Scanning Proton Therapy

    International Nuclear Information System (INIS)

    Sorriaux, J; Paganetti, H; Testa, M; Giantsoudi, D; Schuemann, J; Bertrand, D; Orban de Xivry, J.; Lee, J; Palmans, H; Vynckier, S; Sterpin, E

    2014-01-01

    Purpose: In current practice, most proton therapy centers apply IAEA TRS-398 reference dosimetry protocol. Quality correction factors (kQ) take into account in the dose determination process the differences in beam qualities used for calibration unit and for treatment unit. These quality correction factors are valid for specific reference conditions. TRS-398 reference conditions should be achievable in both scattered proton beams (i.e. DS) and scanned proton beams (i.e. PBS). However, it is not a priori clear if TRS-398 kQ data, which are based on Monte Carlo (MC) calculations in scattered beams, can be used for scanned beams. Using TOPAS-Geant4 MC simulations, the study aims to determine whether broad beam quality correction factors calculated in TRS-398 can be directly applied to PBS delivery modality. Methods: As reference conditions, we consider a 10×10×10 cm 3 homogeneous dose distribution delivered by PBS system in a water phantom (32/10 cm range/modulation) and an air cavity placed at the center of the spread-out-Bragg-peak. In order to isolate beam differences, a hypothetical broad beam is simulated. This hypothetical beam reproduces exactly the same range modulation, and uses the same energy layers than the PBS field. Ion chamber responses are computed for the PBS and hypothetical beams and then compared. Results: For an air cavity of 2×2×0.2 cm 3 , the ratio of ion chamber responses for the PBS and hypothetical beam qualities is 0.9991 ± 0.0016. Conclusion: Quality correction factors are insensitive to the delivery pattern of the beam (broad beam or PBS), as long as similar dose distributions are achieved. This investigation, for an air cavity, suggests that broad beam quality correction factors published in TRS-398 can be applied for scanned beams. J. Sorriaux is financially supported by a public-private partnership involving the company Ion Beam Applications (IBA)

  3. SU-F-BRD-15: Quality Correction Factors in Scanned Or Broad Proton Therapy Beams Are Indistinguishable

    Energy Technology Data Exchange (ETDEWEB)

    Sorriaux, J; Lee, J [Molecular Imaging Radiotherapy & Oncology, Universite Catholique de Louvain, Brussels (Belgium); ICTEAM Institute, Universite catholique de Louvain, Louvain-la-Neuve (Belgium); Testa, M; Paganetti, H [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, Massachusetts (United States); Bertrand, D; Orban de Xivry, J [Ion Beam Applications, Louvain-la-neuve, Brabant Wallon (Belgium); Palmans, H [EBG MedAustron GmbH, Wiener Neustadt (Austria); National Physical Laboratory, Teddington (United Kingdom); Vynckier, S [Cliniques Universitaires Saint-Luc, Brussels (Belgium); Sterpin, E [Molecular Imaging Radiotherapy & Oncology, Universite Catholique de Louvain, Brussels (Belgium)

    2015-06-15

    Purpose: The IAEA TRS-398 code of practice details the reference conditions for reference dosimetry of proton beams using ionization chambers and the required beam quality correction factors (kQ). Pencil beam scanning (PBS) requires multiple spots to reproduce the reference conditions. The objective is to demonstrate, using Monte Carlo (MC) calculations, that kQ factors for broad beams can be used for scanned beams under the same reference conditions with no significant additional uncertainty. We consider hereafter the general Alfonso formalism (Alfonso et al, 2008) for non-standard beam. Methods: To approach the reference conditions and the associated dose distributions, PBS must combine many pencil beams with range modulation and shaping techniques different than those used in passive systems (broad beams). This might lead to a different energy spectrum at the measurement point. In order to evaluate the impact of these differences on kQ factors, ion chamber responses are computed with MC (Geant4 9.6) in a dedicated scanned pencil beam (Q-pcsr) producing a 10×10cm2 composite field with a flat dose distribution from 10 to 16 cm depth. Ion chamber responses are also computed by MC in a broad beam with quality Q-ds (double scattering). The dose distribution of Q -pcsr matches the dose distribution of Q-ds. k-(Q-pcsr,Q-ds) is computed for a 2×2×0.2cm{sup 3} idealized air cavity and a realistic plane-parallel ion chamber (IC). Results: Under reference conditions, quality correction factors for a scanned composite field versus a broad beam are the same for air cavity dose response, k-(Q-pcsr,Q-ds) =1.001±0.001 and for a Roos IC, k-(Q-pcsr,Q-ds) =0.999±0.005. Conclusion: Quality correction factors for ion chamber response in scanned and broad proton therapy beams are identical under reference conditions within the calculation uncertainties. The results indicate that quality correction factors published in IAEA TRS-398 can be used for scanned beams in the SOBP of a

  4. SU-F-BRD-15: Quality Correction Factors in Scanned Or Broad Proton Therapy Beams Are Indistinguishable

    International Nuclear Information System (INIS)

    Sorriaux, J; Lee, J; Testa, M; Paganetti, H; Bertrand, D; Orban de Xivry, J; Palmans, H; Vynckier, S; Sterpin, E

    2015-01-01

    Purpose: The IAEA TRS-398 code of practice details the reference conditions for reference dosimetry of proton beams using ionization chambers and the required beam quality correction factors (kQ). Pencil beam scanning (PBS) requires multiple spots to reproduce the reference conditions. The objective is to demonstrate, using Monte Carlo (MC) calculations, that kQ factors for broad beams can be used for scanned beams under the same reference conditions with no significant additional uncertainty. We consider hereafter the general Alfonso formalism (Alfonso et al, 2008) for non-standard beam. Methods: To approach the reference conditions and the associated dose distributions, PBS must combine many pencil beams with range modulation and shaping techniques different than those used in passive systems (broad beams). This might lead to a different energy spectrum at the measurement point. In order to evaluate the impact of these differences on kQ factors, ion chamber responses are computed with MC (Geant4 9.6) in a dedicated scanned pencil beam (Q-pcsr) producing a 10×10cm2 composite field with a flat dose distribution from 10 to 16 cm depth. Ion chamber responses are also computed by MC in a broad beam with quality Q-ds (double scattering). The dose distribution of Q -pcsr matches the dose distribution of Q-ds. k-(Q-pcsr,Q-ds) is computed for a 2×2×0.2cm 3 idealized air cavity and a realistic plane-parallel ion chamber (IC). Results: Under reference conditions, quality correction factors for a scanned composite field versus a broad beam are the same for air cavity dose response, k-(Q-pcsr,Q-ds) =1.001±0.001 and for a Roos IC, k-(Q-pcsr,Q-ds) =0.999±0.005. Conclusion: Quality correction factors for ion chamber response in scanned and broad proton therapy beams are identical under reference conditions within the calculation uncertainties. The results indicate that quality correction factors published in IAEA TRS-398 can be used for scanned beams in the SOBP of a high

  5. The correction of vibration in frequency scanning interferometry based absolute distance measurement system for dynamic measurements

    Science.gov (United States)

    Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

    2015-10-01

    Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.

  6. A New Collinear-Type Energy-Filtered X-ray Photoemission Electron Microscope Equipped with a Multi-Pole Aberration-Corrected Air-Core Coil Wien Filter

    Science.gov (United States)

    Miyamoto, Takeshi; Wada, Takahiro; Niimi, Hironobu; Suzuki, Shushi; Kato, Makoto; Kudo, Masato; Asakura, Kiyotaka

    2012-04-01

    We present the prototype of a new, collinear-type energy-filtered X-ray photoemission electron microscope (EXPEEM) using a multi-pole, aberration-corrected air-core coil Wien filter (WF) analyzer. We have designed the new WF with 12-pole electrodes and magnetic poles to reduce spherical aberrations and fringe effects. We assess the performance of the WF using an electron energy analyzer for PEEM. The sensitivity is enhanced 10-100 fold compared with a simple, two electrodes plus two magnetic poles type WF. Cu 2p3/2 and Au 4f7/2 photoelectron energy selected images are obtained in a laboratory-scale source within several minutes. The energy and spatial resolutions of our prototype EXPEEM are estimated to be 3 eV and 7 µm, respectively.

  7. Model-Based Angular Scan Error Correction of an Electrothermally-Actuated MEMS Mirror.

    Science.gov (United States)

    Zhang, Hao; Xu, Dacheng; Zhang, Xiaoyang; Chen, Qiao; Xie, Huikai; Li, Suiqiong

    2015-12-10

    In this paper, the actuation behavior of a two-axis electrothermal MEMS (Microelectromechanical Systems) mirror typically used in miniature optical scanning probes and optical switches is investigated. The MEMS mirror consists of four thermal bimorph actuators symmetrically located at the four sides of a central mirror plate. Experiments show that an actuation characteristics difference of as much as 4.0% exists among the four actuators due to process variations, which leads to an average angular scan error of 0.03°. A mathematical model between the actuator input voltage and the mirror-plate position has been developed to predict the actuation behavior of the mirror. It is a four-input, four-output model that takes into account the thermal-mechanical coupling and the differences among the four actuators; the vertical positions of the ends of the four actuators are also monitored. Based on this model, an open-loop control method is established to achieve accurate angular scanning. This model-based open loop control has been experimentally verified and is useful for the accurate control of the mirror. With this control method, the precise actuation of the mirror solely depends on the model prediction and does not need the real-time mirror position monitoring and feedback, greatly simplifying the MEMS control system.

  8. Stellar aberration correction and thermoelastic compensation of Swarm μASC attitude observationsA comment to the Express Letter "Mysterious misalignments between geomagnetic and stellar reference frames seen in CHAMP and Swarm satellite measurements", by Stefan Maus

    Science.gov (United States)

    Herceg, M.; Jørgensen, P. S.; Jørgensen, J. L.

    2017-11-01

    The Swarm constellation of three satellites measures the magnetic signal of the Earth using both a Vector Field Magnetometer and an Absolute Scalar Magnetometer. A Micro Advanced Stellar Compass (μASC) mounted on a common, supposedly stable, optical bench precisely determines its inertial attitude. However, comparison of the Inter Boresight Angle shows a relative attitude variation between the μASC Camera Head Units. These misalignments between Camera Head Units and a geomagnetic reference frame cannot be explained by incorrect aberration correction (as theorized by Maus). Herceg et al. found them to be caused by thermal gradient sensitivity of the optical bench system, opposing the underlying assumption of perfect platform stability. The results after applying thermal corrections show significant decrease in root mean square, with Inter Boresight Angle of thermally corrected data being nearly flat and clean from any variation caused by thermoelastic effects.

  9. Partial-volume effect correction in positron emission tomography brain scan image using super-resolution image reconstruction.

    Science.gov (United States)

    Meechai, T; Tepmongkol, S; Pluempitiwiriyawej, C

    2015-02-01

    The partial-volume effect (PVE) is a consequence of limited (i.e. finite) spatial resolution. PVE can lead to quantitative underestimation of activity concentrations in reconstructed images, which may result in misinterpretation of positron emission tomography (PET) scan images, especially in the brain. The PVE becomes significant when the dimensions of a source region are less than two to three times the full width at half maximum spatial resolution of the imaging system. In the present study, the ability of super-resolution (SR) image reconstruction to compensate for PVE in PET was characterized. The ability of SR image reconstruction technique to recover activity concentrations in small structures was evaluated by comparing images before and after image reconstruction in the NEMA/IEC phantom (Washington, DC), in the Hoffman brain phantom and in four human brain subjects (three normal subjects and one atrophic brain subject) in terms of apparent recovery coefficient (ARC) and percentage yield. Both the ARC and percentage yield are improved after SR implementation in NEMA/IEC phantom and Hoffman brain phantom. When tested in normal subjects, SR implementation can improve the intensity and justify SR efficiency to correct PVE. SR algorithm can be used to effectively correct PVE in PET images. The current research focused on brain PET scanning exclusively; future work will extend to whole-body imaging.

  10. Joint denoising and distortion correction of atomic scale scanning transmission electron microscopy images

    Science.gov (United States)

    Berkels, Benjamin; Wirth, Benedikt

    2017-09-01

    Nowadays, modern electron microscopes deliver images at atomic scale. The precise atomic structure encodes information about material properties. Thus, an important ingredient in the image analysis is to locate the centers of the atoms shown in micrographs as precisely as possible. Here, we consider scanning transmission electron microscopy (STEM), which acquires data in a rastering pattern, pixel by pixel. Due to this rastering combined with the magnification to atomic scale, movements of the specimen even at the nanometer scale lead to random image distortions that make precise atom localization difficult. Given a series of STEM images, we derive a Bayesian method that jointly estimates the distortion in each image and reconstructs the underlying atomic grid of the material by fitting the atom bumps with suitable bump functions. The resulting highly non-convex minimization problems are solved numerically with a trust region approach. Existence of minimizers and the model behavior for faster and faster rastering are investigated using variational techniques. The performance of the method is finally evaluated on both synthetic and real experimental data.

  11. A new method to detect and correct sample tilt in scanning transmission electron microscopy bright-field imaging

    Energy Technology Data Exchange (ETDEWEB)

    Brown, H.G. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Ishikawa, R.; Sánchez-Santolino, G. [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan); Lugg, N.R., E-mail: shibata@sigma.t.u-tokyo.ac.jp [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan); Ikuhara, Y. [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan); Allen, L.J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Shibata, N. [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan)

    2017-02-15

    Important properties of functional materials, such as ferroelectric shifts and octahedral distortions, are associated with displacements of the positions of lighter atoms in the unit cell. Annular bright-field scanning transmission electron microscopy is a good experimental method for investigating such phenomena due to its ability to image light and heavy atoms simultaneously. To map atomic positions at the required accuracy precise angular alignment of the sample with the microscope optical axis is necessary, since misalignment (tilt) of the specimen contributes to errors in position measurements of lighter elements in annular bright-field imaging. In this paper it is shown that it is possible to detect tilt with the aid of images recorded using a central bright-field detector placed within the inner radius of the annular bright-field detector. For a probe focus near the middle of the specimen the central bright-field image becomes especially sensitive to tilt and we demonstrate experimentally that misalignment can be detected with a precision of less than a milliradian, as we also confirm in simulation. Coma in the probe, an aberration that can be misidentified as tilt of the specimen, is also investigated and it is shown how the effects of coma and tilt can be differentiated. The effects of tilt may be offset to a large extent by shifting the diffraction plane detector an amount equivalent to the specimen tilt and we provide an experimental proof of principle of this using a segmented detector system. - Highlights: • Octahedral distortions are associated with displacements of lighter atoms. • Annular bright-field imaging is sensitive to light and heavy atoms simultaneously. • Mistilt of the specimen leads to errors in position measurements of lighter elements. • It is possible to detect tilt using images taken by a central bright-field detector. • Tilt may be offset by shifting the diffraction plane detector by an equivalent amount.

  12. SU-E-I-60: The Correct Selection of Pitch and Rotation Time for Optimal CT Scanning : The Big Misconception

    International Nuclear Information System (INIS)

    Ranallo, F; Szczykutowicz, T

    2014-01-01

    Purpose: To provide correct guidance in the proper selection of pitch and rotation time for optimal CT imaging with multi-slice scanners. Methods: There exists a widespread misconception concerning the role of pitch in patient dose with modern multi-slice scanners, particularly with the use of mA modulation techniques. We investigated the relationship of pitch and rotation time to image quality, dose, and scan duration, with CT scanners from different manufacturers in a way that clarifies this misconception. This source of this misconception may concern the role of pitch in single slice CT scanners. Results: We found that the image noise and dose are generally independent of the selected effective mAs (mA*time/ pitch) with manual mA technique settings and are generally independent of the selected pitch and /or rotation time with automatic mA modulation techniques. However we did find that on certain scanners the use of a pitch just above 0.5 provided images of equal image noise at a lower dose compared to the use of a pitch just below 1.0. Conclusion: The misconception that the use of a lower pitch over-irradiates patients by wasting dose is clearly false. The use of a lower pitch provides images of equal or better image quality at the same patient dose, whether using manual mA or automatic mA modulation techniques. By decreasing the pitch and the rotation times by equal amounts, both helical and patient motion artifacts can be reduced without affecting the exam time. The use of lower helical pitch also allows better scanning of larger patients by allowing a greater scan effective mAs, if the exam time can be extended. The one caution with the use of low pitch is not related to patient dose, but to the length of the scan time if the rotation time is not set short enough. Partial Research funding from GE HealthCare

  13. Characterization of Artifacts Introduced by the Empirical Volcano-Scan Atmospheric Correction Commonly Applied to CRISM and OMEGA Near-Infrared Spectra

    Science.gov (United States)

    Wiseman, S.M.; Arvidson, R.E.; Wolff, M. J.; Smith, M. D.; Seelos, F. P.; Morgan, F.; Murchie, S. L.; Mustard, J. F.; Morris, R. V.; Humm, D.; hide

    2014-01-01

    The empirical volcano-scan atmospheric correction is widely applied to Martian near infrared CRISM and OMEGA spectra between 1000 and 2600 nanometers to remove prominent atmospheric gas absorptions with minimal computational investment. This correction method employs division by a scaled empirically-derived atmospheric transmission spectrum that is generated from observations of the Martian surface in which different path lengths through the atmosphere were measured and transmission calculated using the Beer-Lambert Law. Identifying and characterizing both artifacts and residual atmospheric features left by the volcano-scan correction is important for robust interpretation of CRISM and OMEGA volcano scan corrected spectra. In order to identify and determine the cause of spectral artifacts introduced by the volcano-scan correction, we simulated this correction using a multiple scattering radiative transfer algorithm (DISORT). Simulated transmission spectra that are similar to actual CRISM- and OMEGA-derived transmission spectra were generated from modeled Olympus Mons base and summit spectra. Results from the simulations were used to investigate the validity of assumptions inherent in the volcano-scan correction and to identify artifacts introduced by this method of atmospheric correction. We found that the most prominent artifact, a bowl-shaped feature centered near 2000 nanometers, is caused by the inaccurate assumption that absorption coefficients of CO2 in the Martian atmosphere are independent of column density. In addition, spectral albedo and slope are modified by atmospheric aerosols. Residual atmospheric contributions that are caused by variable amounts of dust aerosols, ice aerosols, and water vapor are characterized by the analysis of CRISM volcano-scan corrected spectra from the same location acquired at different times under variable atmospheric conditions.

  14. Correction

    CERN Multimedia

    2002-01-01

    Tile Calorimeter modules stored at CERN. The larger modules belong to the Barrel, whereas the smaller ones are for the two Extended Barrels. (The article was about the completion of the 64 modules for one of the latter.) The photo on the first page of the Bulletin n°26/2002, from 24 July 2002, illustrating the article «The ATLAS Tile Calorimeter gets into shape» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.

  15. Novel use of gamma correction for precise {sup 99m}Tc-HDP pinhole bone scan diagnosis and classification of knee occult fractures

    Energy Technology Data Exchange (ETDEWEB)

    Bahk, Yong-Whee [Sung Ae General Hospital, Department of Nuclear Medicine, Seoul (Korea); Jeon, Ho-Seung [Sung Ae General Hospital, Department of Orthopedic Surgery, Seoul (Korea); Kim, Jang Min [Sung Ae General Hospital, Department of Radiology, Seoul (Korea); Park, Jung Mee; Kim, Sung-Hoon; Chung, Soo-Kyo [The Catholic University of Korea, Department of Radiology, College of Medicine, Seoul (Korea); Chung, Yong-An [The Catholic University of Korea, Department of Radiology, College of Medicine, Seoul (Korea); Incheon St. Mary' s Hospital, Institute of Catholic Integrative Medicine (ICIM), Incheon (Korea); Incheon St. Mary' s Hospital, The Catholic University of Korea, Department of Radiology, Incheon (Korea); Kim, E.E. [University of Texas MD Anderson Cancer Center, Department of Radiology and Nuclear Medicine, Houston, TX (United States)

    2010-08-15

    The aim of this study was to introduce gamma correction pinhole bone scan (GCPBS) to depict specific signs of knee occult fractures (OF) on {sup 99m}Tc-hydroxydiphosphonate (HDP) scan. Thirty-six cases of six different types of knee OF in 27 consecutive patients (male = 20, female = 7, and age = 18-86 years) were enrolled. The diagnosis was made on the basis of a history of acute or subacute knee trauma, local pain, tenderness, cutaneous injury, negative conventional radiography, and positive magnetic resonance imaging (MRI). Because of the impracticability of histological verification of individual OF, MRI was utilized as a gold standard of diagnosis and classification. All patients had {sup 99m}Tc-HDP bone scanning and supplementary GCPBS. GCPBS signs were correlated and compared with those of MRI. The efficacy of gamma correction of ordinary parallel collimator and pinhole collimator scans were collated. Gamma correction pinhole bone scan depicted the signs characteristic of six different types of OF. They were well defined stuffed globular tracer uptake in geographic I fractures (n = 9), block-like uptake in geographic II fractures (n = 7), simple or branching linear uptake in linear cancellous fractures (n = 4), compression in impacted fractures (n = 2), stippled-serpentine uptake in reticular fractures (n = 11), and irregular subcortical uptake in osteochondral fractures (n = 3). All fractures were equally well or more distinctly depicted on GCPBS than on MRI except geographic II fracture, the details of which were not appreciated on GCPBS. Parallel collimator scan also yielded to gamma correction, but the results were inferior to those of the pinhole scan. Gamma correction pinhole bone scan can depict the specific diagnostic signs in six different types of knee occult fractures. The specific diagnostic capability along with the lower cost and wider global availability of bone scanning would make GCPBS an effective alternative. (orig.)

  16. Correction

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Regarding Gorelik, G., & Shackelford, T.K. (2011. Human sexual conflict from molecules to culture. Evolutionary Psychology, 9, 564–587: The authors wish to correct an omission in citation to the existing literature. In the final paragraph on p. 570, we neglected to cite Burch and Gallup (2006 [Burch, R. L., & Gallup, G. G., Jr. (2006. The psychobiology of human semen. In S. M. Platek & T. K. Shackelford (Eds., Female infidelity and paternal uncertainty (pp. 141–172. New York: Cambridge University Press.]. Burch and Gallup (2006 reviewed the relevant literature on FSH and LH discussed in this paragraph, and should have been cited accordingly. In addition, Burch and Gallup (2006 should have been cited as the originators of the hypothesis regarding the role of FSH and LH in the semen of rapists. The authors apologize for this oversight.

  17. Correction

    CERN Multimedia

    2002-01-01

    The photo on the second page of the Bulletin n°48/2002, from 25 November 2002, illustrating the article «Spanish Visit to CERN» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.   The Spanish delegation, accompanied by Spanish scientists at CERN, also visited the LHC superconducting magnet test hall (photo). From left to right: Felix Rodriguez Mateos of CERN LHC Division, Josep Piqué i Camps, Spanish Minister of Science and Technology, César Dopazo, Director-General of CIEMAT (Spanish Research Centre for Energy, Environment and Technology), Juan Antonio Rubio, ETT Division Leader at CERN, Manuel Aguilar-Benitez, Spanish Delegate to Council, Manuel Delfino, IT Division Leader at CERN, and Gonzalo León, Secretary-General of Scientific Policy to the Minister.

  18. Correction

    Directory of Open Access Journals (Sweden)

    2014-01-01

    Full Text Available Regarding Tagler, M. J., and Jeffers, H. M. (2013. Sex differences in attitudes toward partner infidelity. Evolutionary Psychology, 11, 821–832: The authors wish to correct values in the originally published manuscript. Specifically, incorrect 95% confidence intervals around the Cohen's d values were reported on page 826 of the manuscript where we reported the within-sex simple effects for the significant Participant Sex × Infidelity Type interaction (first paragraph, and for attitudes toward partner infidelity (second paragraph. Corrected values are presented in bold below. The authors would like to thank Dr. Bernard Beins at Ithaca College for bringing these errors to our attention. Men rated sexual infidelity significantly more distressing (M = 4.69, SD = 0.74 than they rated emotional infidelity (M = 4.32, SD = 0.92, F(1, 322 = 23.96, p < .001, d = 0.44, 95% CI [0.23, 0.65], but there was little difference between women's ratings of sexual (M = 4.80, SD = 0.48 and emotional infidelity (M = 4.76, SD = 0.57, F(1, 322 = 0.48, p = .29, d = 0.08, 95% CI [−0.10, 0.26]. As expected, men rated sexual infidelity (M = 1.44, SD = 0.70 more negatively than they rated emotional infidelity (M = 2.66, SD = 1.37, F(1, 322 = 120.00, p < .001, d = 1.12, 95% CI [0.85, 1.39]. Although women also rated sexual infidelity (M = 1.40, SD = 0.62 more negatively than they rated emotional infidelity (M = 2.09, SD = 1.10, this difference was not as large and thus in the evolutionary theory supportive direction, F(1, 322 = 72.03, p < .001, d = 0.77, 95% CI [0.60, 0.94].

  19. Evaluation of residual aberration in fifth-order geometrical aberration correctors.

    Science.gov (United States)

    Morishita, Shigeyuki; Kohno, Yuji; Hosokawa, Fumio; Suenaga, Kazu; Sawada, Hidetaka

    2018-02-21

    Higher order geometrical aberration correctors for transmission electron microscopes are essential for atomic-resolution imaging, especially at low-accelerating voltages. We quantitatively calculated the residual aberrations of fifth-order aberration correctors to determine the dominant aberrations. The calculations showed that the sixth-order three-lobe aberration was dominant when fifth-order aberrations were corrected by using the double-hexapole or delta types of aberration correctors. It was also deduced that the sixth-order three-lobe aberration was generally smaller in the delta corrector than in the double-hexapole corrector. The sixth-order three-lobe aberration was counterbalanced with a finite amount of the fourth-order three-lobe aberration and 3-fold astigmatism. In the experiments, we used a low-voltage microscope equipped with delta correctors for probe- and image-forming systems. Residual aberrations in each system were evaluated using Ronchigrams and diffractogram tableaux, respectively. The counterbalanced aberration correction was applied to obtain high-resolution transmission electron microscopy images of graphene and WS2 samples at 60 and 15 kV, respectively.

  20. Atomically resolved structure of ligand-protected Au{sub 9} clusters on TiO{sub 2} nanosheets using aberration-corrected STEM

    Energy Technology Data Exchange (ETDEWEB)

    Al Qahtani, Hassan S.; Andersson, Gunther G., E-mail: gunther.andersson@flinders.edu.au, E-mail: nakayama.tomonobu@nims.go.jp [Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001 (Australia); Kimoto, Koji [National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044 (Japan); Bennett, Trystan; Alvino, Jason F.; Metha, Gregory F. [Department of Chemistry, The University of Adelaide, Adelaide SA 5005 (Australia); Golovko, Vladimir B. [Department of Chemistry, The MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch 8140 (New Zealand); Sasaki, Takayoshi; Nakayama, Tomonobu, E-mail: gunther.andersson@flinders.edu.au, E-mail: nakayama.tomonobu@nims.go.jp [WPI-MANA, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2016-03-21

    Triphenylphosphine ligand-protected Au{sub 9} clusters deposited onto titania nanosheets show three different atomic configurations as observed by scanning transmission electron microscopy. The configurations observed are a 3-dimensional structure, corresponding to the previously proposed Au{sub 9} core of the clusters, and two pseudo-2-dimensional (pseudo-2D) structures, newly found by this work. With the help of density functional theory (DFT) calculations, the observed pseudo-2D structures are attributed to the low energy, de-ligated structures formed through interaction with the substrate. The combination of scanning transmission electron microscopy with DFT calculations thus allows identifying whether or not the deposited Au{sub 9} clusters have been de-ligated in the deposition process.

  1. Quantifying the effect of corrective surgery for trigonocephaly: A non-invasive, non-ionizing method using three-dimensional handheld scanning and statistical shape modelling

    NARCIS (Netherlands)

    Rodriguez-Florez, N. (Naiara); Göktekin, Ö.K. (Özge K.); Bruse, J.L. (Jan L.); Borghi, A. (Alessandro); F. Angullia (Freida); Knoops, P.G.M. (Paul G.M.); Tenhagen, M. (Maik); O'Hara, J.L. (Justine L.); M.J. Koudstaal (Maarten); Schievano, S. (Silvia); Jeelani, N.U.O. (N.U. Owase); James, G. (Greg); D.J. Dunaway (David)

    2016-01-01

    textabstractTrigonocephaly in patients with metopic synostosis is corrected by fronto-orbital remodelling (FOR). The aim of this study was to quantitatively assess aesthetic outcomes of FOR by capturing 3D forehead scans of metopic patients pre- and post-operatively and comparing them with controls.

  2. Ion recombination and polarity correction factors for a plane-parallel ionization chamber in a proton scanning beam.

    Science.gov (United States)

    Liszka, Małgorzata; Stolarczyk, Liliana; Kłodowska, Magdalena; Kozera, Anna; Krzempek, Dawid; Mojżeszek, Natalia; Pędracka, Anna; Waligórski, Michael Patrick Russell; Olko, Paweł

    2018-01-01

    To evaluate the effect on charge collection in the ionization chamber (IC) in proton pencil beam scanning (PBS), where the local dose rate may exceed the dose rates encountered in conventional MV therapy by up to three orders of magnitude. We measured values of the ion recombination (k s ) and polarity (k pol ) correction factors in water, for a plane-parallel Markus TM23343 IC, using the cyclotron-based Proteus-235 therapy system with an active proton PBS of energies 30-230 MeV. Values of k s were determined from extrapolation of the saturation curve and the Two-Voltage Method (TVM), for planar fields. We compared our experimental results with those obtained from theoretical calculations. The PBS dose rates were estimated by combining direct IC measurements with results of simulations performed using the FLUKA MC code. Values of k s were also determined by the TVM for uniformly irradiated volumes over different ranges and modulation depths of the proton PBS, with or without range shifter. By measuring charge collection efficiency versus applied IC voltage, we confirmed that, with respect to ion recombination, our proton PBS represents a continuous beam. For a given chamber parameter, e.g., nominal voltage, the value of k s depends on the energy and the dose rate of the proton PBS, reaching c. 0.5% for the TVM, at the dose rate of 13.4 Gy/s. For uniformly irradiated regular volumes, the k s value was significantly smaller, within 0.2% or 0.3% for irradiations with or without range shifter, respectively. Within measurement uncertainty, the average value of k pol , for the Markus TM23343 IC, was close to unity over the whole investigated range of clinical proton beam energies. While no polarity effect was observed for the Markus TM23343 IC in our pencil scanning proton beam system, the effect of volume recombination cannot be ignored. © 2017 American Association of Physicists in Medicine.

  3. HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY 1ST QUARTER 2010 MILESTONE REPORT: Simulations of fast correction of chromatic aberrations to establish physics specifications for implementation on NDCX-1 and NDCX-2

    International Nuclear Information System (INIS)

    Lidia, S.M.; Lund, S.M.; Seidl, P.A.

    2010-01-01

    This milestone has been accomplished. The Heavy Ion Fusion Science Virtual National Laboratory has completed simulations of a fast correction scheme to compensate for chromatic and time-dependent defocusing effects in the transport of ion beams to the target plane in the NDCX-1 facility. Physics specifications for implementation in NDCX-1 and NDCX-2 have been established. This milestone has been accomplished. The Heavy Ion Fusion Science Virtual National Laboratory has completed simulations of a fast correction scheme to compensate for chromatic and time-dependent defocusing effects in the transport of ion beams to the target plane in the NDCX-1 facility. Physics specifications for implementation in NDCX-1 and NDCX-2 have been established. Focal spot differences at the target plane between the compressed and uncompressed regions of the beam pulse have been modeled and measured on NDCX-1. Time-dependent focusing and energy sweep from the induction bunching module are seen to increase the compressed pulse spot size at the target plane by factors of two or more, with corresponding scaled reduction in the peak intensity and fluence on target. A time-varying beam envelope correction lens has been suggested to remove the time-varying aberration. An Einzel (axisymmetric electric) lens system has been analyzed and optimized for general transport lines, and as a candidate correction element for NDCX-1. Attainable high-voltage holdoff and temporal variations of the lens driving waveform are seen to effect significant changes on the beam envelope angle over the duration of interest, thus confirming the utility of such an element on NDCX-1. Modeling of the beam dynamics in NDCX-1 was performed using a time-dependent (slice) envelope code and with the 3-D, self-consistent, particle-in-cell code WARP. Proof of concept was established with the slice envelope model such that the spread in beam waist positions relative to the target plane can be minimized with a carefully designed

  4. Partial-Volume Effect Correction Improves Quantitative Analysis of 18F-Florbetaben β-Amyloid PET Scans.

    Science.gov (United States)

    Rullmann, Michael; Dukart, Juergen; Hoffmann, Karl-Titus; Luthardt, Julia; Tiepolt, Solveig; Patt, Marianne; Gertz, Hermann-Josef; Schroeter, Matthias L; Seibyl, John; Schulz-Schaeffer, Walter J; Sabri, Osama; Barthel, Henryk

    2016-02-01

    Neocortical atrophy reduces PET signal intensity, potentially affecting the diagnostic efficacy of β-amyloid (Aβ) brain PET imaging. This study investigated whether partial-volume effect correction (PVEC), adjusting for this atrophy bias, improves the accuracy of (18)F-florbetaben Aβ PET. We analyzed (18)F-florbetaben PET and MRI data obtained from 3 cohorts. The first was 10 patients with probable Alzheimer disease (AD) and 10 age-matched healthy controls (HCs), the second was 31 subjects who underwent in vivo imaging and postmortem histopathology for Aβ plaques, and the third was 5 subjects who underwent PET and MRI at baseline and 1 y later. The imaging data were coregistered and segmented. PVEC was performed using the voxel-based modified Müller-Gärtner method (PVELab, SPM8). From the PET data, regional and composite SUV ratios (SUVRs) with and without PVEC were obtained. In the MRI data, mesial temporal lobe atrophy was determined by the Scheltens mesial temporal atrophy scale and gray matter volumes by voxel-based morphometry. In cohort 1, PVEC increased the effect on AD-versus-HC discrimination from a Cohen d value of 1.68 to 2.0 for composite SUVRs and from 0.04 to 1.04 for mesial temporal cortex SUVRs. The PVEC-related increase in mesial temporal cortex SUVR correlated with the Scheltens score (r = 0.84, P < 0.001), and that of composite SUVR correlated with the composite gray matter volume (r = -0.75, P < 0.001). In cohort 2, PVEC increased the correlation coefficient between mesial temporal cortex SUVR and histopathology score for Aβ plaque load from 0.28 (P = 0.09) to 0.37 (P = 0.03). In cohort 3, PVEC did not affect the composite SUVR dynamics over time for the Aβ-negative subject. This finding was in contrast to the 4 Aβ-positive subjects, in 2 of whom PVEC changed the composite SUVR dynamics. The influence of PVEC on (18)F-florbetaben PET data is associated with the degree of brain atrophy. Thus, PVEC increases the ability of (18)F

  5. Evaluation of the ICS and DEW scatter correction methods for low statistical content scans in 3D PET

    International Nuclear Information System (INIS)

    Sossi, V.; Oakes, T.R.; Ruth, T.J.

    1996-01-01

    The performance of the Integral Convolution and the Dual Energy Window scatter correction methods in 3D PET has been evaluated over a wide range of statistical content of acquired data (1M to 400M events) The order in which scatter correction and detector normalization should be applied has also been investigated. Phantom and human neuroreceptor studies were used with the following figures of merit: axial and radial uniformity, sinogram and image noise, contrast accuracy and contrast accuracy uniformity. Both scatter correction methods perform reliably in the range of number of events examined. Normalization applied after scatter correction yields better radial uniformity and fewer image artifacts

  6. A study of respiration-correlated cone-beam CT scans to correct target positioning errors in radiotherapy of thoracic cancer

    International Nuclear Information System (INIS)

    Santoro, J. P.; McNamara, J.; Yorke, E.; Pham, H.; Rimner, A.; Rosenzweig, K. E.; Mageras, G. S.

    2012-01-01

    Purpose: There is increasingly widespread usage of cone-beam CT (CBCT) for guiding radiation treatment in advanced-stage lung tumors, but difficulties associated with daily CBCT in conventionally fractionated treatments include imaging dose to the patient, increased workload and longer treatment times. Respiration-correlated cone-beam CT (RC-CBCT) can improve localization accuracy in mobile lung tumors, but further increases the time and workload for conventionally fractionated treatments. This study investigates whether RC-CBCT-guided correction of systematic tumor deviations in standard fractionated lung tumor radiation treatments is more effective than 2D image-based correction of skeletal deviations alone. A second study goal compares respiration-correlated vs respiration-averaged images for determining tumor deviations. Methods: Eleven stage II–IV nonsmall cell lung cancer patients are enrolled in an IRB-approved prospective off-line protocol using RC-CBCT guidance to correct for systematic errors in GTV position. Patients receive a respiration-correlated planning CT (RCCT) at simulation, daily kilovoltage RC-CBCT scans during the first week of treatment and weekly scans thereafter. Four types of correction methods are compared: (1) systematic error in gross tumor volume (GTV) position, (2) systematic error in skeletal anatomy, (3) daily skeletal corrections, and (4) weekly skeletal corrections. The comparison is in terms of weighted average of the residual GTV deviations measured from the RC-CBCT scans and representing the estimated residual deviation over the treatment course. In the second study goal, GTV deviations computed from matching RCCT and RC-CBCT are compared to deviations computed from matching respiration-averaged images consisting of a CBCT reconstructed using all projections and an average-intensity-projection CT computed from the RCCT. Results: Of the eleven patients in the GTV-based systematic correction protocol, two required no correction

  7. Evaluation of the dependence of the exposure dose on the attenuation correction in brain PET/CT scans using 18F-FDG

    Science.gov (United States)

    Choi, Eun-Jin; Jeong, Moon-Taeg; Jang, Seong-Joo; Choi, Nam-Gil; Han, Jae-Bok; Yang, Nam-Hee; Dong, Kyung-Rae; Chung, Woon-Kwan; Lee, Yun-Jong; Ryu, Young-Hwan; Choi, Sung-Hyun; Seong, Kyeong-Jeong

    2014-01-01

    This study examined whether scanning could be performed with minimum dose and minimum exposure to the patient after an attenuation correction. A Hoffman 3D Brain Phantom was used in BIO_40 and D_690 PET/CT scanners, and the CT dose for the equipment was classified as a low dose (minimum dose), medium dose (general dose for scanning) and high dose (dose with use of contrast medium) before obtaining the image at a fixed kilo-voltage-peak (kVp) and milliampere (mA) that were adjusted gradually in 17-20 stages. A PET image was then obtained to perform an attenuation correction based on an attenuation map before analyzing the dose difference. Depending on tube current in the range of 33-190 milliampere-second (mAs) when BIO_40 was used, a significant difference in the effective dose was observed between the minimum and the maximum mAs (p effective dose was increased by approximately 5.26-fold. Depending on the change in the tube current in the range of 10-200 mA when D_690 was used, a significant difference in the effective dose was observed between the minimum and the maximum of mA (p effective exposure dose increases with increasing operating current, it is possible to reduce the exposure limit in a brain scan can be reduced if the CT dose can be minimized for a transmission scan.

  8. Varied-space grazing incidence gratings in high resolution scanning spectrometers

    International Nuclear Information System (INIS)

    Hettrick, M.C.; Underwood, J.H.

    1986-10-01

    We discuss the dominant geometrical aberrations of a grazing incidence reflection grating and new techniques which can be used to reduce or eliminate them. Convergent beam geometries and the aberration correction possible with varied groove spacings are each found to improve the spectral resolution and speed of grazing incidence gratings. In combination, these two techniques can result in a high resolution (λ/Δλ > 10 4 ) monochromator or scanning spectrometer with a simple rotational motion for scanning wavelength or selecting the spectral band. 21 refs., 4 figs

  9. Pixelized measurement of {sup 99m}Tc-HDP micro particles formed in gamma correction phantom pinhole scan: A reference study

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joo Young; Yoon, Do Kyun; Chung, Yong An [Catholic University of Korea, College of Medicine, Seoul (Korea, Republic of); Cheon, Gi Jeong; Lee, Yun Sang; Ha, Seunggyun [Radiopharmaceutical Science Laboratory, Dept. of Nuclear MedicineSeoul National University, College of Medicine, Seoul (Korea, Republic of); Bahk, Yong Whee [Dept. of Nuclear Medicine, Sung Ae General Hospital, Seoul (Korea, Republic of)

    2016-09-15

    Currently, traumatic bone diseases are diagnosed by assessing the micro {sup 99m}Tc-hydroxymethylene diphosphonate (HDP) uptake in injured trabeculae with ongoing osteoneogenesis demonstrated by gamma correction pinhole scan (GCPS). However, the mathematic size quantification of micro-uptake is not yet available. We designed and performed this phantom-based study to set up an in-vitro model of the mathematical calculation of micro-uptake by the pixelized measurement. The micro {sup 99m}Tc-HDP deposits used in this study were spontaneously formed both in a large standard flood and small house-made dish phantoms. The processing was as follows: first, phantoms were flooded with distilled water and {sup 99m}Tc-HDP was therein injected to induce micro {sup 99m}Tc-HDP deposition; second, the deposits were scanned using parallel-hole and pinhole collimator to generally survey {sup 99m}Tc-HDP deposition pattern; and third, the scans underwent gamma correction (GC) to discern individual deposits for size measurement. In original naïve scans, tracer distribution was simply nebulous in appearance and, hence, could not be measured. Impressively, however, GCPS could discern individual micro deposits so that they were calculated by pixelized measurement. Phantoms naturally formed micro {sup 99m}Tc-HDP deposits that are analogous to {sup 99m}Tc-HDP uptake on in-vivo bone scan. The smallest one we measured was 0.414 mm. Flooded phantoms and therein injected {sup 99m}Tc-HDP form nebulous micro {sup 99m}Tc-HDP deposits that are rendered discernible by GCPB and precisely calculable using pixelized measurement. This method can be used for precise quantitative and qualitative diagnosis of bone and joint diseases at the trabecular level.

  10. Environmental TEM in an Aberration Corrected Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal

    ‐resolution imaging. A gaseous atmosphere in the pole‐piece gap of the objective lens of the microscope alters both the incoming electron wave prior to interaction with the sample and the outgoing wave below the sample. Whereas conventional TEM samples are usually thin (below 10‐20 nm), the gas in the environmental...... the microscope column. The effects of gas on the electron wave in the objective lens are not well understood and needs further attention. Imaging samples with a simple geometry, such as gold particles on a flat graphene substrate and analyzing the variations in contrast, provides a means for understanding...... results from imaging in various elemental as well as di‐molecular gases and their effect on imaging and spectroscopy in the environmental transmission electron microscope....

  11. List-Mode PET Motion Correction Using Markerless Head Tracking: Proof-of-Concept With Scans of Human Subject

    DEFF Research Database (Denmark)

    Olesen, Oline Vinter; Sullivan, Jenna M.; Mulnix, Tim

    2013-01-01

    A custom designed markerless tracking system was demonstrated to be applicable for positron emission tomography (PET) brain imaging. Precise head motion registration is crucial for accurate motion correction (MC) in PET imaging. State-of-the-art tracking systems applied with PET brain imaging rel...

  12. Higher order aberrations in amblyopic children and their role in refractory amblyopia

    Directory of Open Access Journals (Sweden)

    Arnaldo Dias-Santos

    2014-12-01

    Full Text Available Objective: Some studies have hypothesized that an unfavourable higher order aberrometric profile could act as an amblyogenic mechanism and may be responsible for some amblyopic cases that are refractory to conventional treatment or cases of “idiopathic” amblyopia. This study compared the aberrometric profile in amblyopic children to that of children with normal visual development and compared the aberrometric profile in corrected amblyopic eyes and refractory amblyopic eyes with that of healthy eyes. Methods: Cross-sectional study with three groups of children – the CA group (22 eyes of 11 children with unilateral corrected amblyopia, the RA group (24 eyes of 13 children with unilateral refractory amblyopia and the C group (28 eyes of 14 children with normal visual development. Higher order aberrations were evaluated using an OPD-Scan III (NIDEK. Comparisons of the aberrometric profile were made between these groups as well as between the amblyopic and healthy eyes within the CA and RA groups. Results: Higher order aberrations with greater impact in visual quality were not significantly higher in the CA and RA groups when compared with the C group. Moreover, there were no statistically significant differences in the higher order aberrometric profile between the amblyopic and healthy eyes within the CA and RA groups. Conclusions: Contrary to lower order aberrations (e.g., myopia, hyperopia, primary astigmatism, higher order aberrations do not seem to be involved in the etiopathogenesis of amblyopia. Therefore, these are likely not the cause of most cases of refractory amblyopia.

  13. Root Cause Analysis and Correction of Single Metal Contact Open-Induced Scan Chain Failure in 90nm node VLSI

    OpenAIRE

    Ting, Chao-Cheng; Liu, Ya-Chi; Chen, Hsuan-Hsien; Tsai, Chung-Ching; Shih, Liwen

    2018-01-01

    In this paper, the localization of open metal contact for 90nm node SOC is reported based on Electron Beam Absorbed Current (EBAC) technique and scan diagnosis for the first time. According to the detected excess carbon, silicon and oxygen signals obtained from X-ray energy dispersive spectroscopy (EDX), the failure was deemed to be caused by the incomplete removal of silicate photoresist polymer formed during the O2 plasma dry clean before copper plating. Based on this, we proposed to replac...

  14. On the sensitivity of probe-corrected spherical near-field antenna measurements with high-order probes using double phi-step theta-scanning scheme against various measurement uncertainties

    DEFF Research Database (Denmark)

    Laitinen, Tommi; Pivnenko, Sergey; Nielsen, Jeppe Majlund

    2011-01-01

    In this paper, the relatively recently introduced double phi-step theta-scanning scheme and the probe correction technique associated with it is examined against the traditional phi-scanning scheme and the first-order probe correction. The important result of this paper is that the double phi......-step theta-scanning scheme is shown to be clearly less sensitive to the probe misalignment errors compared to the phi-scanning scheme. The two methods show similar sensitivity to noise and channel balance error....

  15. Subject-specific bone attenuation correction for brain PET/MR: can ZTE-MRI substitute CT scan accurately?

    Science.gov (United States)

    Khalifé, Maya; Fernandez, Brice; Jaubert, Olivier; Soussan, Michael; Brulon, Vincent; Buvat, Irène; Comtat, Claude

    2017-10-01

    In brain PET/MR applications, accurate attenuation maps are required for accurate PET image quantification. An implemented attenuation correction (AC) method for brain imaging is the single-atlas approach that estimates an AC map from an averaged CT template. As an alternative, we propose to use a zero echo time (ZTE) pulse sequence to segment bone, air and soft tissue. A linear relationship between histogram normalized ZTE intensity and measured CT density in Hounsfield units (HU ) in bone has been established thanks to a CT-MR database of 16 patients. Continuous AC maps were computed based on the segmented ZTE by setting a fixed linear attenuation coefficient (LAC) to air and soft tissue and by using the linear relationship to generate continuous μ values for the bone. Additionally, for the purpose of comparison, four other AC maps were generated: a ZTE derived AC map with a fixed LAC for the bone, an AC map based on the single-atlas approach as provided by the PET/MR manufacturer, a soft-tissue only AC map and, finally, the CT derived attenuation map used as the gold standard (CTAC). All these AC maps were used with different levels of smoothing for PET image reconstruction with and without time-of-flight (TOF). The subject-specific AC map generated by combining ZTE-based segmentation and linear scaling of the normalized ZTE signal into HU was found to be a good substitute for the measured CTAC map in brain PET/MR when used with a Gaussian smoothing kernel of 4~mm corresponding to the PET scanner intrinsic resolution. As expected TOF reduces AC error regardless of the AC method. The continuous ZTE-AC performed better than the other alternative MR derived AC methods, reducing the quantification error between the MRAC corrected PET image and the reference CTAC corrected PET image.

  16. Reactivation of latently infected HIV-1 viral reservoirs and correction of aberrant alternative splicing in the LMNA gene via AMPK activation: Common mechanism of action linking HIV-1 latency and Hutchinson-Gilford progeria syndrome.

    Science.gov (United States)

    Finley, Jahahreeh

    2015-09-01

    AMPK, a master regulator of cellular metabolism which has been shown to activate PKC-theta (θ) and is essential for T cell activation, may modulate the splicing activities of SRp55 as well as enhance a p32-mediated inhibition of ASF/SF2-induced alternative splicing, potentially correcting aberrant alternative splicing in the LMNA gene and reactivating latent viral HIV-1 reservoirs. Moreover, similar epigenetic modifications and cell cycle regulators also characterize the analogous stages of premature senescence in progeroid cells and latency in HIV-1 infected T cells. AMPK-activating compounds including metformin and resveratrol may thus embody a novel treatment paradigm linking the pathophysiology of HGPS with that of HIV-1 latency. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Digital adaptive optics line-scanning confocal imaging system

    Science.gov (United States)

    Liu, Changgeng; Kim, Myung K.

    2015-01-01

    Abstract. A digital adaptive optics line-scanning confocal imaging (DAOLCI) system is proposed by applying digital holographic adaptive optics to a digital form of line-scanning confocal imaging system. In DAOLCI, each line scan is recorded by a digital hologram, which allows access to the complex optical field from one slice of the sample through digital holography. This complex optical field contains both the information of one slice of the sample and the optical aberration of the system, thus allowing us to compensate for the effect of the optical aberration, which can be sensed by a complex guide star hologram. After numerical aberration compensation, the corrected optical fields of a sequence of line scans are stitched into the final corrected confocal image. In DAOLCI, a numerical slit is applied to realize the confocality at the sensor end. The width of this slit can be adjusted to control the image contrast and speckle noise for scattering samples. DAOLCI dispenses with the hardware pieces, such as Shack–Hartmann wavefront sensor and deformable mirror, and the closed-loop feedbacks adopted in the conventional adaptive optics confocal imaging system, thus reducing the optomechanical complexity and cost. Numerical simulations and proof-of-principle experiments are presented that demonstrate the feasibility of this idea. PMID:26140334

  18. Beam hardening and smoothing correction effects on performance of micro-ct SkyScan 1173 for imaging low contrast density materials

    Energy Technology Data Exchange (ETDEWEB)

    Sriwayu, Wa Ode [Physics Departement, Haluoleo University Indonesia (Indonesia); Haryanto, Freddy; Khotimah, Siti Nurul; Latief, Fourier Dzar Eljabbar [Physics Departement, ITB Indonesia email : ayoe-fisika@yahoo.com (Indonesia)

    2015-04-16

    We have designed and fabricated phantom mimicking breast cancer composition known as a region that has low contrast density. The used compositions are a microcalcifications, fatty tissues and tumor mass by using Al{sub 2}O{sub 3}, C{sub 27}H{sub 46}O, and hard nylon materials. Besides, phantom also has a part to calculate low cost criteria /CNR (Contrast to Noise Ratio). Uniformity will be measured at water distillation medium located in a part of phantom scale contrast. Phantom will be imaged by using micro ct-sky scan 1173 high energy type, and then also can be quantified CT number to examine SkyScan 1173 performance in imaging low contrast density materials. Evaluation of CT number is done at technique configuration parameter using voltage of 30 kV, exposure 0.160 mAs, and camera resolution 560x560 pixel, the effect of image quality to reconstruction process is evaluated by varying image processing parameters in the form of beam hardening corrections with amount of 25%, 66% and100% with each smoothing level S10,S2 and S7. To obtain the better high quality image, the adjustment of beam hardening correction should be 66% and smoothing level reach maximal value at level 10.

  19. Evaluating the Correctness of Airborne Laser Scanning Data Heights Using Vehicle-Based RTK and VRS GPS Observations

    Directory of Open Access Journals (Sweden)

    Martin Vermeer

    2011-08-01

    Full Text Available In this study, we describe a system in which a GPS receiver mounted on the roof of a car is used to provide reference information to evaluate the elevation accuracy and georeferencing of airborne laser scanning (ALS point clouds. The concept was evaluated in the Klaukkala test area where a number of roads were traversed to collect real-time kinematic data. Two test cases were evaluated, including one case using the real-time kinematic (RTK method with a dedicated GPS base station at a known benchmark in the area and another case using the GNSSnet virtual reference station service (VRS. The utility of both GPS methods was confirmed. When all test data were included, the mean difference between ALS data and GPS-based observations was −2.4 cm for both RTK and VRS GPS cases. The corresponding dispersions were ±4.5 cm and ±5.9 cm, respectively. In addition, our examination did not reveal the presence of any significant rotation between ALS and GPS data.

  20. Simulação computacional de cirurgias foto-refrativas personalizadas e precisão relacionada à ordem das aberrações ópticas Computational simulation of customized photorefractive surgery and precision of correction related to different order aberrations

    Directory of Open Access Journals (Sweden)

    Luis Alberto Vieira de Carvalho

    2007-12-01

    Full Text Available O objetivo principal deste trabalho foi o desenvolvimento e a implementação de um algoritmo para simulação de cirurgias foto-refrativas. Sabe-se que os atuais " flying-spot" lasers para cirurgia refrativa disponíveis no mercado ainda contêm limitações na correção de algumas aberrações de ordem alta. No entanto, há muito pouca informação quantitativa sobre os erros envolvidos em função da complexidade das aberrações. Aplicando-se superfícies objetivo descritas por uma série de coeficientes de Zernike e o conceito matemático de convolução, várias ablações personalizadas foram simuladas para várias aberrações, desde baixa ordem (esfero-cilíndricas até aberrações de décima ordem (como coma, aberração esférica, entre outras. Os resultados mostram que o perfil de ablação de cada pulso do laser assim como seu diâmetro são fatores críticos quando o objetivo é corrigir aberrações de alta ordem. Além disso, outras conclusões foram possíveis, como por exemplo a de que nem todas as aberrações de alta ordem induzem aos mesmos erros na ablação. Também foi possível verificar que a correção de aberrações de alta ordem nos termos radiais (como aberração esférica é bem mais difícil do que naqueles termos contendo alta frequência angular (como trefoil.PURPOSE: To develop and implement an algorithm for simulation of photorefractive surgery. It is well known that many flying-spot lasers in the market have limitations in correcting higher order aberrations, but there is little quantitative information about errors related to aberration complexity. METHODS: By applying known surfaces described by Zernike polynomials of different orders it was possible to simulate several target surfaces that may well resemble in vivo cases of refractive surgery candidates. An algorithm that uses the mathematical concept of convolution was implemented and several simulated surfaces were tested, ranging from low order

  1. Alteration of introns in a hyaluronan synthase 1 (HAS1 minigene convert Pre-mRNA [corrected] splicing to the aberrant pattern in multiple myeloma (MM: MM patients harbor similar changes.

    Directory of Open Access Journals (Sweden)

    Jitra Kriangkum

    Full Text Available Aberrant pre-mRNA splice variants of hyaluronan synthase 1 (HAS1 have been identified in malignant cells from cancer patients. Bioinformatic analysis suggests that intronic sequence changes can underlie aberrant splicing. Deletions and mutations were introduced into HAS1 minigene constructs to identify regions that can influence aberrant intronic splicing, comparing the splicing pattern in transfectants with that in multiple myeloma (MM patients. Introduced genetic variations in introns 3 and 4 of HAS1 as shown here can promote aberrant splicing of the type detected in malignant cells from MM patients. HAS1Vd is a novel intronic splice variant first identified here. HAS1Vb, an intronic splice variant previously identified in patients, skips exon 4 and utilizes the same intron 4 alternative 3'splice site as HAS1Vd. For transfected constructs with unaltered introns 3 and 4, HAS1Vd transcripts are readily detectable, frequently to the exclusion of HAS1Vb. In contrast, in MM patients, HAS1Vb is more frequent than HAS1Vd. In the HAS1 minigene, combining deletion in intron 4 with mutations in intron 3 leads to a shift from HAS1Vd expression to HAS1Vb expression. The upregulation of aberrant splicing, exemplified here by the expression of HAS1Vb, is shown here to be influenced by multiple genetic changes in intronic sequences. For HAS1Vb, this includes enhanced exon 4 skipping and increased usage of alternative 3' splice sites. Thus, the combination of introduced mutations in HAS1 intron3 with introduced deletions in HAS1 intron 4 promoted a shift to an aberrant splicing pattern previously shown to be clinically significant. Most MM patients harbor genetic variations in intron 4, and as shown here, nearly half harbor recurrent mutations in HAS1 intron 3. Our work suggests that aberrant intronic HAS1 splicing in MM patients may rely on intronic HAS1 deletions and mutations that are frequent in MM patients but absent from healthy donors.

  2. Study of ocular aberrations with age.

    Science.gov (United States)

    Athaide, Helaine Vinche Zampar; Campos, Mauro; Costa, Charles

    2009-01-01

    Aging has various effects on visual system. Vision deteriorate, contrast sensitivity decreases and ocular aberrations apparently make the optical quality worse across the years. To prospective evaluate ocular aberrations along the ages. Three hundred and fifteen patients were examined, 155 were male (39.36%) and 160 were female (60.63%). Ages ranged from 5 to 64 year-old, the study was performed from February to November, 2004. Patients were divided into 4 age-groups according to IBGE (Instituto Brasileiro de Geografia e Estatística) classification: 68 patients from 5 to 14 year-old, 55 patients from 15 to 24 year-old, 116 from 25 to 44 year-old and 76 from 45 to 67 year-old. All patients had the following characteristics: best corrected visual acuity > 20/25, emmetropia or spherical equivalent < 3.50 SD, refractive astigmatism < 1.75 CD on cycloplegic refraction, normal ophthalmologic exam and no previous ocular surgeries. This protocol was approved by Federal University of São Paulo Institutional Review Board. Total optical aberrations were measured by H-S sensor LadarWave Custom Cornea Wavefront System (Alcon Laboratories Inc, Orlando, FLA, USA) and were statistically analysed. Corneal aberrations were calculated using CT-View software Version 6.89 (Sarver and Associates, Celebration, FL, USA). Lens aberrations were calculated by subtraction. High-order (0.32 e 0.48 microm) and ocular spherical aberrations (0.02 e 0.26 microm) increased respectively in child and middle age groups. High order (0.27 microm) and corneal spherical aberrations (0.05 microm) did not show changes with age. Lens showed a statistically significant spherical aberration increase (from -0.02 to 0.22 microm). Vertical (from 0.10 to -0.07 microm) and horizontal coma (from 0.01 to -0.12 microm) presented progressively negative values with aging. High-order and spherical aberrations increased with age due to lens contribution. The cornea did not affect significantly changes observed on ocular

  3. Aberrant hepatic artery

    International Nuclear Information System (INIS)

    Konstam, M.A.; Novelline, R.A.; Athanasoulis, C.A.

    1979-01-01

    In a patient undergoing selective hepatic arteriography for suspected liver trauma, a nonopacified area of the liver, initially thought to represent a hepatic hematoma, was later discovered to be due to the presence of an accessory right hepatic artery arising from the superior mesenteric artery. This case illustrates the need for a search for aberrant vasculature whenever a liver hematoma is suspected on the basis of a selective hepatic arteriogram. (orig.) [de

  4. The Effects of Misalignment between PET and CT Scans on Brain PET Study Using CT-based Attenuation Correction: A Phantom Study.

    Science.gov (United States)

    Shimizu, Akihide; Terakawa, Yusuke; Morita, Naomi; Koshino, Kazuhiro; Iida, Hidehiro

    2016-01-01

    The aim of this study was to evaluate the effects of inaccurate attenuation correction due to the misalignment between the computed tomography (CT)-based μ-map and the positron emission tomography (PET) data on a brain PET. CT and PET scans were performed on a 3-dimension (3D) brain phantom, in which the grey matter region was filled with 18 F-fluorodeoxyglucose ( 18 F-FDG), and the skull region was filled with/without the bone-equivalent solution. The shifted PET images relative to the CT image were generated by the software-based translation of PET data in the cephalad/caudal and right directions, with a magnitude of the shift up to 30 mm and a step size of 5 mm. The regions of interest (ROIs) were drawn on the areas of the temporal lobes, parietal lobes, thalami, and cerebellums in the no-shifted image (reference). For each ROI, the radioactivity concentrations in the shifted images were compared with those of the reference. The errors in the radioactivity concentrations were increased with the increasing magnitude of the shift in all brain regions except for thalamus. For a 5 mm shift in the right direction, ± 10% errors were observed in the left/right temporal lobes. The accuracy of the radioactivity concentration in the temporal lobe was very sensitive to misalignment in the right directions. The misalignment between CT-based μ-map and PET data had larger effects on the surface regions of the brain rather than on deep brain structures.

  5. Stellar aberration correction and thermoelastic compensation of Swarm μASC attitude observations: A comment to the Express Letter “Mysterious misalignments between geomagnetic and stellar reference frames seen in CHAMP and Swarm satellite measurements”, by Stefan Maus

    DEFF Research Database (Denmark)

    Herceg, M.; Jørgensen, P. S.; Jørgensen, J. L.

    2017-01-01

    The Swarm constellation of three satellites measures the magnetic signal of the Earth using both a Vector Field Magnetometer and an Absolute Scalar Magnetometer. A Micro Advanced Stellar Compass (μASC) mounted on a common, supposedly stable, optical bench precisely determines its inertial attitude...... to be caused by thermal gradient sensitivity of the optical bench system, opposing the underlying assumption of perfect platform stability. The results after applying thermal corrections show significant decrease in root mean square, with Inter Boresight Angle of thermally corrected data being nearly flat...

  6. High-resolution adaptive optics scanning laser ophthalmoscope with multiple deformable mirrors

    Science.gov (United States)

    Chen, Diana C.; Olivier, Scot S.; Jones; Steven M.

    2010-02-23

    An adaptive optics scanning laser ophthalmoscopes is introduced to produce non-invasive views of the human retina. The use of dual deformable mirrors improved the dynamic range for correction of the wavefront aberrations compared with the use of the MEMS mirror alone, and improved the quality of the wavefront correction compared with the use of the bimorph mirror alone. The large-stroke bimorph deformable mirror improved the capability for axial sectioning with the confocal imaging system by providing an easier way to move the focus axially through different layers of the retina.

  7. Photon Sieve Bandwidth Broadening by Reduction of Chromatic Aberration Effects Using Second-Stage Diffractive Optics

    Science.gov (United States)

    2015-03-26

    thesis. 25 Still another manner in which to view chromatic aberration is in terms of Lateral Chromatic Aberration ( LCA ). Eq. 18 illustrates a...wavelength in addition to the in-focus location. This difference in height of images at two different colors is LCA (21:268). Aberration Correction... electrons incident on one detector pixel (Ne) during a set camera integration time (t), multiply Eq. 28 by this time as well as T and η (32:8), yielding

  8. Corneal versus ocular aberrations after overnight orthokeratology.

    Science.gov (United States)

    Gifford, Paul; Li, Melanie; Lu, Helen; Miu, Jonathan; Panjaya, Monica; Swarbrick, Helen A

    2013-05-01

    To investigate relationships between changes to corneal and ocular aberrations induced by orthokeratology (OK) and their influence on visual function. Eighteen subjects (aged 20 to 23 years) were fitted with OK lenses (BE Enterprises Pty Ltd, Australia), manufactured in Boston XO material (Bausch & Lomb Boston, Wilmington, MA), and worn overnight for seven nights. Corneal and ocular aberrations were simultaneously captured (Discovery, Innovative Visual Systems, Elmhurst, IL), and contrast sensitivity function was measured on days 1 and 7, within 2 and 8 hours after lens removal on waking. Data from the eye achieving the higher myopic correction were analyzed for changes over time. There was a significant refractive effect at all visits. Orthokeratology induced an increase in corneal and ocular root mean square higher order aberrations (HOAs) and a positive shift in spherical aberration (SA) on day 1, with further increases by day 7. Increases in root mean square coma became significant by day 7. Changes to corneal and ocular SA were similar on day 1; however, by day 7, there was a greater increase in corneal than ocular SA, indicating a change in internal SA. Orthokeratology led to an overall decrease in contrast sensitivity function, which was isolated to spatial frequency changes on day 1 at 1 cycle per degree and on day 7 at 1 and 8 cycles per degree. A greater positive shift in corneal compared with ocular SA on day 7 suggests a negative shift in internal SA, which would be consistent with an increased accommodative response. Lack of any difference on day 1 indicates that this may be an ocular adaptation response toward neutralizing induced positive SA, rather than a direct effect of SA changes on the accommodation mechanism.

  9. Methods for Motion Correction Evaluation Using 18F-FDG Human Brain Scans on a High-Resolution PET Scanner

    DEFF Research Database (Denmark)

    Keller, Sune H.; Sibomana, Merence; Olesen, Oline Vinter

    2012-01-01

    by the optical motion tracking system) were selected from F-18-FDG scans acquired on a PET scanner. The motion was measured as the maximum displacement of the markers attached to the subject's head and was considered to be major if larger than 4 mm and minor if less than 2 mm. After allowing a 40- to 60-min...... uptake time after tracer injection, we acquired a 6-min transmission scan, followed by a 40-min emission list-mode scan. Each emission list-mode dataset was divided into 8 frames of 5 min. The reconstructed time-framed images were aligned to a selected reference frame using either EMT or the AIR...

  10. Volumetric optical coherence microscopy enabled by aberrated optics (Conference Presentation)

    Science.gov (United States)

    Mulligan, Jeffrey A.; Liu, Siyang; Adie, Steven G.

    2017-02-01

    Optical coherence microscopy (OCM) is an interferometric imaging technique that enables high resolution, non-invasive imaging of 3D cell cultures and biological tissues. Volumetric imaging with OCM suffers a trade-off between high transverse resolution and poor depth-of-field resulting from defocus, optical aberrations, and reduced signal collection away from the focal plane. While defocus and aberrations can be compensated with computational methods such as interferometric synthetic aperture microscopy (ISAM) or computational adaptive optics (CAO), reduced signal collection must be physically addressed through optical hardware. Axial scanning of the focus is one approach, but comes at the cost of longer acquisition times, larger datasets, and greater image reconstruction times. Given the capabilities of CAO to compensate for general phase aberrations, we present an alternative method to address the signal collection problem without axial scanning by using intentionally aberrated optical hardware. We demonstrate the use of an astigmatic spectral domain (SD-)OCM imaging system to enable single-acquisition volumetric OCM in 3D cell culture over an extended depth range, compared to a non-aberrated SD-OCM system. The transverse resolution of the non-aberrated and astigmatic imaging systems after application of CAO were 2 um and 2.2 um, respectively. The depth-range of effective signal collection about the nominal focal plane was increased from 100 um in the non-aberrated system to over 300 um in the astigmatic system, extending the range over which useful data may be acquired in a single OCM dataset. We anticipate that this method will enable high-throughput cellular-resolution imaging of dynamic biological systems over extended volumes.

  11. The Impact of Model-Based Clutter Suppression on Cluttered, Aberrated Wavefronts.

    Science.gov (United States)

    Dei, Kazuyuki; Byram, Brett

    2017-10-01

    Recent studies reveal that both phase aberration and reverberation play a major role in degrading ultrasound image quality. We previously developed an algorithm for suppressing clutter, but we have not yet tested it in the context of aberrated wavefronts. In this paper, we evaluate our previously reported algorithm, called aperture domain model image reconstruction (ADMIRE), in the presence of phase aberration and in the presence of multipath scattering and phase aberration. We use simulations to investigate phase aberration corruption and correction in the presence of reverberation. As part of this paper, we observed that ADMIRE leads to suppressed levels of aberration. In order to accurately characterize aberrated signals of interest, we introduced an adaptive component to ADMIRE to account for aberration, referred to as adaptive ADMIRE. We then use ADMIRE, adaptive ADMIRE, and conventional filtering methods to characterize aberration profiles on in vivo liver data. These in vivo results suggest that adaptive ADMIRE could be used to better characterize a wider range of aberrated wavefronts. The aberration profiles' full-width at half-maximum of ADMIRE, adaptive ADMIRE, and postfiltered data with 0.4- mm -1 spatial cutoff frequency are 4.0 ± 0.28 mm, 2.8 ± 1.3 mm, and 2.8 ± 0.57 mm, respectively, while the average root-mean square values in the same order are 16 ± 5.4 ns, 20 ± 6.3 ns, and 19 ± 3.9 ns, respectively. Finally, because ADMIRE suppresses aberration, we perform a limited evaluation of image quality using simulations and in vivo data to determine how ADMIRE and adaptive ADMIRE perform with and without aberration correction.

  12. Measurement of eye aberrations in a speckle field

    International Nuclear Information System (INIS)

    Larichev, A V; Ivanov, P V; Iroshnikov, N G; Shmalgauzen, V I

    2001-01-01

    The influence of speckles on the performance of a Shark-Hartmann wavefront sensor is investigated in the eye aberration studies. The dependence of the phase distortion measurement error on the characteristic speckle size is determined experimentally. Scanning of the reference source was used to suppress the speckle structure of the laser beam scattered by the retina. The technique developed by us made it possible to study the time dependence of the human eye aberrations with a resolution of 30 ms. (laser applications and other topics in quantum electronics)

  13. DNA Repair Defects and Chromosomal Aberrations

    Science.gov (United States)

    Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

  14. Optimization of transmission-scan time for the FixER method: a MR-based PET attenuation correction with a weak fixed-position external radiation source

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, Hiroshi; Hirano, Yoshiyuki; Kershaw, Jeff; Yoshida, Eiji [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba (Japan); Shiraishi, Takahiro [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba (Japan); Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Suga, Mikio [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba (Japan); Center for Frontier Medical Engineering, Chiba University (Japan); Obata, Takayuki [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba (Japan); Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Ito, Hiroshi; Yamaya, Taiga [Molecular Imaging Center, National Institute of Radiological Sciences, Chiba (Japan)

    2014-07-29

    In recent work, we proposed an MRI-based attenuation-coefficient (μ-value) estimation method that uses a weak fixed-position external radiation source to construct an attenuation map for PET/MRI. In this presentation we refer to this method as FixER, and perform a series of simulations to investigate the duration of the transmission scan required to accurately estimate μ-values.

  15. Theory of aberration fields for general optical systems with freeform surfaces.

    Science.gov (United States)

    Fuerschbach, Kyle; Rolland, Jannick P; Thompson, Kevin P

    2014-11-03

    This paper utilizes the framework of nodal aberration theory to describe the aberration field behavior that emerges in optical systems with freeform optical surfaces, particularly φ-polynomial surfaces, including Zernike polynomial surfaces, that lie anywhere in the optical system. If the freeform surface is located at the stop or pupil, the net aberration contribution of the freeform surface is field constant. As the freeform optical surface is displaced longitudinally away from the stop or pupil of the optical system, the net aberration contribution becomes field dependent. It is demonstrated that there are no new aberration types when describing the aberration fields that arise with the introduction of freeform optical surfaces. Significantly it is shown that the aberration fields that emerge with the inclusion of freeform surfaces in an optical system are exactly those that have been described by nodal aberration theory for tilted and decentered optical systems. The key contribution here lies in establishing the field dependence and nodal behavior of each freeform term that is essential knowledge for effective application to optical system design. With this development, the nodes that are distributed throughout the field of view for each aberration type can be anticipated and targeted during optimization for the correction or control of the aberrations in an optical system with freeform surfaces. This work does not place any symmetry constraints on the optical system, which could be packaged in a fully three dimensional geometry, without fold mirrors.

  16. Analysis of four aberrometers for evaluating lower and higher order aberrations.

    Directory of Open Access Journals (Sweden)

    Fabiano Cade

    Full Text Available PURPOSE: To compare the measurements of lower and higher order aberrations (HOA of 4 commonly used aberrometers. SETTING: Massachusetts Eye & Ear Infirmary, Boston, USA. DESIGN: Prospective, cross-sectional study, in a controlled, single-blinded fashion. METHODS: Multiple readings were obtained in 42 eyes of 21 healthy volunteers, at a single visit, with each of the following aberrometers: Alcon LADARWave®, Visx WaveScan®, B & L Zywave®, and Wavelight Allegro Analyzer®. Results were compared and analyzed in regards to the lower and HOA, to the different wavefront sensing devices and software, Tscherning and Hartmann-Shack and between the Fourier and Zernike algorithms. Statistical analysis included Bland-Altman plots, Intraclass Correlation Coefficient (ICC, multiple comparison tests with Analysis of Variance and Kruskal-Wallis. Significant level was set to p<0.05 and alpha level correction was adjusted under the Bonferroni criteria. RESULTS: Most measurements of all 4 aberrometers were comparable. However, statistically significant differences were found between the aberrometers in total HOA (tHOA, spherical aberration (SA, horizontal coma and astigmatism (2,2. LADARwave and Wavescan showed significant differences in tHOA (P<0.001, ICC = 0.549, LoA = 0.19±0.5 and in SA (P<0.001, ICC = 0.733, LoA = 0.16±0.37. Wavescan showed a significant difference compared to Zywave (p<0.001, ICC = 0.920, LoA = 0.09±0.13 in SA. Comparisons between Allegro Analyzer and Zywave demonstrated significant differences in both Horizontal Coma (3,1 (p<0.001, ICC = -0.207, LoA = -0.15±0.48 and Astigmatism (2,2 (P = 0.003, ICC = -0.965, LoA = 0.2±2.5. Allegro Analyzer also differed from Wavescan in Horizontal Coma (3,1 (P<0.001, ICC = 0.725, LoA = -0.07±0.25. CONCLUSIONS: Although some measurements were comparable predominately in the lower order aberrations, significant differences were found in the tHOA, SA, horizontal coma and astigmatism. Our analysis

  17. Chromosome Aberrations by Heavy Ions

    Science.gov (United States)

    Ballarini, Francesca; Ottolenghi, Andrea

    It is well known that mammalian cells exposed to ionizing radiation can show different types of chromosome aberrations (CAs) including dicentrics, translocations, rings, deletions and complex exchanges. Chromosome aberrations are a particularly relevant endpoint in radiobiology, because they play a fundamental role in the pathways leading either to cell death, or to cell conversion to malignancy. In particular, reciprocal translocations involving pairs of specific genes are strongly correlated (and probably also causally-related) with specific tumour types; a typical example is the BCR-ABL translocation for Chronic Myeloid Leukaemia. Furthermore, aberrations can be used for applications in biodosimetry and more generally as biomarkers of exposure and risk, that is the case for cancer patients monitored during Carbon-ion therapy and astronauts exposed to space radiation. Indeed hadron therapy and astronauts' exposure to space radiation represent two of the few scenarios where human beings can be exposed to heavy ions. After a brief introduction on the main general features of chromosome aberrations, in this work we will address key aspects of the current knowledge on chromosome aberration induction, both from an experimental and from a theoretical point of view. More specifically, in vitro data will be summarized and discussed, outlining important issues such as the role of interphase death/mitotic delay and that of complex-exchange scoring. Some available in vivo data on cancer patients and astronauts will be also reported, together with possible interpretation problems. Finally, two of the few available models of chromosome aberration induction by ionizing radiation (including heavy ions) will be described and compared, focusing on the different assumptions adopted by the authors and on how these models can deal with heavy ions.

  18. Aberration corrected STEM to study an ancient hair dyeing formula

    Science.gov (United States)

    Patriarche, G.; Van Elslande, E.; Castaing, J.; Walter, P.

    2014-05-01

    Lead-based chemistry was initiated in ancient Egypt for cosmetic preparation more than 4000 years ago. Here, we study a hair-dyeing recipe using lead salts described in text since Greco-Roman times. We report direct evidence about the shape and distribution of PbS nanocrystals that form within the hair during blackening.

  19. The Art of Optical Aberrations

    Science.gov (United States)

    Wylde, Clarissa Eileen Kenney

    Art and optics are inseparable. Though seemingly opposite disciplines, the combination of art and optics has significantly impacted both culture and science as they are now known. As history has run its course, in the sciences, arts, and their fruitful combinations, optical aberrations have proved to be a problematic hindrance to progress. In an effort to eradicate aberrations the simple beauty of these aberrational forms has been labeled as undesirable and discarded. Here, rather than approach aberrations as erroneous, these beautiful forms are elevated to be the photographic subject in a new body of work, On the Bright Side. Though many recording methods could be utilized, this work was composed on classic, medium-format, photographic film using white-light, Michelson interferometry. The resulting images are both a representation of the true light rays that interacted on the distorted mirror surfaces (data) and the artist's compositional eye for what parts of the interferogram are chosen and displayed. A detailed description of the captivating interdisciplinary procedure is documented and presented alongside the final artwork, CCD digital reference images, and deformable mirror contour maps. This alluring marriage between the arts and sciences opens up a heretofore minimally explored aspect of the inextricable art-optics connection. It additionally provides a fascinating new conversation on the importance of light and optics in photographic composition.

  20. Seamless stitching of tile scan microscope images.

    Science.gov (United States)

    Legesse, F B; Chernavskaia, O; Heuke, S; Bocklitz, T; Meyer, T; Popp, J; Heintzmann, R

    2015-06-01

    For diagnostic purposes, optical imaging techniques need to obtain high-resolution images of extended biological specimens in reasonable time. The field of view of an objective lens, however, is often smaller than the sample size. To image the whole sample, laser scanning microscopes acquire tile scans that are stitched into larger mosaics. The appearance of such image mosaics is affected by visible edge artefacts that arise from various optical aberrations which manifest in grey level jumps across tile boundaries. In this contribution, a technique for stitching tiles into a seamless mosaic is presented. The stitching algorithm operates by equilibrating neighbouring edges and forcing the brightness at corners to a common value. The corrected image mosaics appear to be free from stitching artefacts and are, therefore, suited for further image analysis procedures. The contribution presents a novel method to seamlessly stitch tiles captured by a laser scanning microscope into a large mosaic. The motivation for the work is the failure of currently existing methods for stitching nonlinear, multimodal images captured by our microscopic setups. Our method eliminates the visible edge artefacts that appear between neighbouring tiles by taking into account the overall illumination differences among tiles in such mosaics. The algorithm first corrects the nonuniform brightness that exists within each of the tiles. It then compensates for grey level differences across tile boundaries by equilibrating neighbouring edges and forcing the brightness at the corners to a common value. After these artefacts have been removed further image analysis procedures can be applied on the microscopic images. Even though the solution presented here is tailored for the aforementioned specific case, it could be easily adapted to other contexts where image tiles are assembled into mosaics such as in astronomical or satellite photos. © 2015 The Authors Journal of Microscopy © 2015 Royal

  1. Origins and fundamentals of nodal aberration theory

    Science.gov (United States)

    Rogers, John R.

    2017-11-01

    Nodal Aberration Theory, developed by Kevin Thompson and Roland Shack, predicts several important aberration phenomena but remains poorly understood. To de-mystify the theory, we describe the origins and fundamental concepts of the theory.

  2. Reducing starbursts in highly aberrated eyes with pupil miosis.

    Science.gov (United States)

    Xu, Renfeng; Kollbaum, Pete; Thibos, Larry; Lopez-Gil, Norberto; Bradley, Arthur

    2018-01-01

    To test the hypothesis that marginal ray deviations determine perceived starburst sizes, and to explore different strategies for decreasing starburst size in highly aberrated eyes. Perceived size of starburst images and visual acuities were measured psychophysically for eyes with varying levels of spherical aberration, pupil sizes, and defocus. Computationally, we use a polychromatic eye model including the typical levels of higher order aberrations (HOAs) for keratoconic and post-LASIK eyes to quantify the image quality (the visually weighted Strehl ratio derived from the optical transfer function, VSOTF) with different pupil sizes at both photopic and mesopic light levels. For distance corrected post-LASIK and keratoconic eyes with a night-time pupil (e.g., 7 mm), the starburst diameter is about 1.5 degrees (1 degree for normal presbyopic eyes), which can be reduced to ≤0.25 degrees with pupil sizes ≤3 mm. Starburst size is predicted from the magnitude of the longitudinal spherical aberration. Refracting the eye to focus the pupil margin also removed starbursts, but, unlike small pupils, significantly degraded visual acuity. Reducing pupil diameter to 3 mm improved image quality for these highly aberrated eyes by about 2.7 ×  to 1.7 ×  relative to the natural pupils when light levels were varied from 0.1 to 1000 cd m -2 , respectively. Subjects with highly aberrated eyes observed larger starbursts around bright lights at night predictable by the deviated marginal rays. These were effectively attenuated by reducing pupil diameters to ≤3 mm, which did not cause a drop in visual acuity or modelled image quality even at mesopic light levels. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

  3. Freeform aberrations in phase space: an example.

    Science.gov (United States)

    Babington, James

    2017-06-01

    We consider how optical propagation and aberrations of freeform systems can be formulated in phase space. As an example system, a freeform prism is analyzed and discussed. Symmetry considerations and their group theory descriptions are given some importance. Numerical aberrations are also highlighted and put into the context of the underlying aberration theory.

  4. Nuclear Scans

    Science.gov (United States)

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  5. Pathophysiology of MDS: genomic aberrations.

    Science.gov (United States)

    Ichikawa, Motoshi

    2016-01-01

    Myelodysplastic syndromes (MDS) are characterized by clonal proliferation of hematopoietic stem/progenitor cells and their apoptosis, and show a propensity to progress to acute myelogenous leukemia (AML). Although MDS are recognized as neoplastic diseases caused by genomic aberrations of hematopoietic cells, the details of the genetic abnormalities underlying disease development have not as yet been fully elucidated due to difficulties in analyzing chromosomal abnormalities. Recent advances in comprehensive analyses of disease genomes including whole-genome sequencing technologies have revealed the genomic abnormalities in MDS. Surprisingly, gene mutations were found in approximately 80-90% of cases with MDS, and the novel mutations discovered with these technologies included previously unknown, MDS-specific, mutations such as those of the genes in the RNA-splicing machinery. It is anticipated that these recent studies will shed new light on the pathophysiology of MDS due to genomic aberrations.

  6. Analysis of nodal aberration properties in off-axis freeform system design.

    Science.gov (United States)

    Shi, Haodong; Jiang, Huilin; Zhang, Xin; Wang, Chao; Liu, Tao

    2016-08-20

    Freeform surfaces have the advantage of balancing off-axis aberration. In this paper, based on the framework of nodal aberration theory (NAT) applied to the coaxial system, the third-order astigmatism and coma wave aberration expressions of an off-axis system with Zernike polynomial surfaces are derived. The relationship between the off-axis and surface shape acting on the nodal distributions is revealed. The nodal aberration properties of the off-axis freeform system are analyzed and validated by using full-field displays (FFDs). It has been demonstrated that adding Zernike terms, up to nine, to the off-axis system modifies the nodal locations, but the field dependence of the third-order aberration does not change. On this basis, an off-axis two-mirror freeform system with 500 mm effective focal length (EFL) and 300 mm entrance pupil diameter (EPD) working in long-wave infrared is designed. The field constant aberrations induced by surface tilting are corrected by selecting specific Zernike terms. The design results show that the nodes of third-order astigmatism and coma move back into the field of view (FOV). The modulation transfer function (MTF) curves are above 0.4 at 20 line pairs per millimeter (lp/mm) which meets the infrared reconnaissance requirement. This work provides essential insight and guidance for aberration correction in off-axis freeform system design.

  7. Frequency and distribution studies of asymmetrical versus symmetrical chromosome aberrations

    International Nuclear Information System (INIS)

    Savage, J.R.K.; Papworth, D.G.

    1982-01-01

    Two aspects of the relationship between Asymmetrical (A) and Symmetrical (S) radiation-induced chromosomal aberrations are considered in this paper. (1) Are A and S truly alternative modes of lesion interaction. Relative frequencies for chromatid-type and chromosome-type are examined, and new lymphocyte data using banding is used to look at this, and also for parallelism in chromosome participation of the two forms for various aberration categories. All the tests applied suggest that A and S are alternative interaction modes. (2) The long-term survival characteristics of A and S are discussed, and the differences in expected frequencies of derived S per surviving cell from chromosome-type and chromatid-types are stressed. Since many in vivo tissues have varying mixtures of potential chromatid and chromosome aberration-bearing target cells, ultimate cell survival and derived S frequencies may differ between tissues for the same absorbed dose. An Appendix gives Relative Corrected Lengths (RCL) for chromosomes of the human karyotype which should be used when testing the various exchange aberration categories for random chromosome participation. (orig.)

  8. A high resolution chromosome image processor for study purposes, NIRS-1000:CHROMO STUDY, and algorithm developing to classify radiation induced aberrations.

    Science.gov (United States)

    Yamamoto, M; Hayata, I; Furuta, S

    1992-03-01

    Since 1989 we have promoted a project to develop an automated scoring system of radiation induced chromosome aberrations. As a first step, a high resolution image processing system for study purposes, NIRS-1000:CHROMO STUDY, has been developed. It is composed of: (1) CHROMO MARKER whose main purpose is to mark on images to make image data base, (2) CHROMO ALGO whose purpose is algorithm development, and (3) METAPHASE RANKER whose purposes are metaphase finding and ranking with a high power objective lens. However, METAPHASE RANKER is presently under development. The system utilizes a high definition video system so as to realize the best spatial resolution that is achievable with an optical microscope using an objective lens (x 100, numerical aperture 1.4). The video camera has 1024 effective scan lines to realize 0.1 microns sampling on a specimen. The system resolution achieved on the hard copy is less than 0.3 microns on a specimen. A preliminary algorithm has been developed to classify the aberrations on the system using projection information of gray level. The preliminary test results on excellent 10 metaphases show that the correct classification ratio is 92.7%, that the detection rate of the aberrations is 83.3% and that the false positive rate is 6.1%.

  9. Political Correctness--Correct?

    Science.gov (United States)

    Boase, Paul H.

    1993-01-01

    Examines the phenomenon of political correctness, its roots and objectives, and its successes and failures in coping with the conflicts and clashes of multicultural campuses. Argues that speech codes indicate failure in academia's primary mission to civilize and educate through talk, discussion, thought,166 and persuasion. (SR)

  10. Design of a Compact, Bimorph Deformable Mirror-Based Adaptive Optics Scanning Laser Ophthalmoscope.

    Science.gov (United States)

    He, Yi; Deng, Guohua; Wei, Ling; Li, Xiqi; Yang, Jinsheng; Shi, Guohua; Zhang, Yudong

    2016-01-01

    We have designed, constructed and tested an adaptive optics scanning laser ophthalmoscope (AOSLO) using a bimorph mirror. The simulated AOSLO system achieves diffraction-limited criterion through all the raster scanning fields (6.4 mm pupil, 3° × 3° on pupil). The bimorph mirror-based AOSLO corrected ocular aberrations in model eyes to less than 0.1 μm RMS wavefront error with a closed-loop bandwidth of a few Hz. Facilitated with a bimorph mirror at a stroke of ±15 μm with 35 elements and an aperture of 20 mm, the new AOSLO system has a size only half that of the first-generation AOSLO system. The significant increase in stroke allows for large ocular aberrations such as defocus in the range of ±600° and astigmatism in the range of ±200°, thereby fully exploiting the AO correcting capabilities for diseased human eyes in the future.

  11. Correlating Atom Probe Tomography with Atomic-Resolved Scanning Transmission Electron Microscopy: Example of Segregation at Silicon Grain Boundaries.

    Science.gov (United States)

    Stoffers, Andreas; Barthel, Juri; Liebscher, Christian H; Gault, Baptiste; Cojocaru-Mirédin, Oana; Scheu, Christina; Raabe, Dierk

    2017-04-01

    In the course of a thorough investigation of the performance-structure-chemistry interdependency at silicon grain boundaries, we successfully developed a method to systematically correlate aberration-corrected scanning transmission electron microscopy and atom probe tomography. The correlative approach is conducted on individual APT and TEM specimens, with the option to perform both investigations on the same specimen in the future. In the present case of a Σ9 grain boundary, joint mapping of the atomistic details of the grain boundary topology, in conjunction with chemical decoration, enables a deeper understanding of the segregation of impurities observed at such grain boundaries.

  12. Chromosomal aberrations in ore miners of Slovakia

    International Nuclear Information System (INIS)

    Beno, M.; Vladar, M.; Nikodemova, D.; Vicanova, M.; Durcik, M.

    1998-01-01

    A pilot study was performed in which the incidence of chromosomal aberrations in lymphocytes of miners in ore mines located in Central Slovakia was monitored and related to lifetime underground radon exposure and to lifetime smoking. The conclusions drawn from the results of the study were as follows: the counts of chromosomal aberrations in lymphocytes of miners were significantly higher than in an age matched control group of white-collar staff; the higher counts of chromosomal aberrations could be ascribed to underground exposure of miners and to smoking; a dependence of chromosomal aberration counts on the exposure to radon could not be assessed. (A.K.)

  13. Digital adaptive optics confocal microscopy based on iterative retrieval of optical aberration from a guidestar hologram.

    Science.gov (United States)

    Liu, Changgeng; Thapa, Damber; Yao, Xincheng

    2017-04-03

    Guidestar hologram based digital adaptive optics (DAO) is one recently emerging active imaging modality. It records each complex distorted line field reflected or scattered from the sample by an off-axis digital hologram, measures the optical aberration from a separate off-axis digital guidestar hologram, and removes the optical aberration from the distorted line fields by numerical processing. In previously demonstrated DAO systems, the optical aberration was directly retrieved from the guidestar hologram by taking its Fourier transform and extracting the phase term. For the direct retrieval method (DRM), when the sample is not coincident with the guidestar focal plane, the accuracy of the optical aberration retrieved by DRM undergoes a fast decay, leading to quality deterioration of corrected images. To tackle this problem, we explore here an image metrics-based iterative method (MIM) to retrieve the optical aberration from the guidestar hologram. Using an aberrated objective lens and scattering samples, we demonstrate that MIM can improve the accuracy of the retrieved aberrations from both focused and defocused guidestar holograms, compared to DRM, to improve the robustness of the DAO.

  14. Automatic phase aberration compensation for digital holographic microscopy based on deep learning background detection.

    Science.gov (United States)

    Nguyen, Thanh; Bui, Vy; Lam, Van; Raub, Christopher B; Chang, Lin-Ching; Nehmetallah, George

    2017-06-26

    We propose a fully automatic technique to obtain aberration free quantitative phase imaging in digital holographic microscopy (DHM) based on deep learning. The traditional DHM solves the phase aberration compensation problem by manually detecting the background for quantitative measurement. This would be a drawback in real time implementation and for dynamic processes such as cell migration phenomena. A recent automatic aberration compensation approach using principle component analysis (PCA) in DHM avoids human intervention regardless of the cells' motion. However, it corrects spherical/elliptical aberration only and disregards the higher order aberrations. Traditional image segmentation techniques can be employed to spatially detect cell locations. Ideally, automatic image segmentation techniques make real time measurement possible. However, existing automatic unsupervised segmentation techniques have poor performance when applied to DHM phase images because of aberrations and speckle noise. In this paper, we propose a novel method that combines a supervised deep learning technique with convolutional neural network (CNN) and Zernike polynomial fitting (ZPF). The deep learning CNN is implemented to perform automatic background region detection that allows for ZPF to compute the self-conjugated phase to compensate for most aberrations.

  15. Scanning Tunneling Microscopy - image interpretation

    International Nuclear Information System (INIS)

    Maca, F.

    1998-01-01

    The basic ideas of image interpretation in Scanning Tunneling Microscopy are presented using simple quantum-mechanical models and supplied with examples of successful application. The importance is stressed of a correct interpretation of this brilliant experimental surface technique

  16. Corneal reshaping and wavefront aberrations during overnight orthokeratology.

    Science.gov (United States)

    Lian, Yan; Shen, Meixiao; Huang, Shenghai; Yuan, Yimin; Wang, Yaozeng; Zhu, Dexi; Jiang, Jun; Mao, Xinjie; Wang, Jianhua; Lu, Fan

    2014-05-01

    To investigate changes of corneal thickness at the vertical and horizontal meridians and of wavefront aberrations (WA) over a 30-day period of overnight myopia orthokeratology (OK) lens wear. Sixteen subjects (11 women, 5 men, 26.3±3.2 years) were enrolled and fitted for OK lenses. Long scan depth optical coherence tomography was used to measure corneal thickness profiles at both horizontal and vertical meridians at baseline and on days 1, 7, and 30 days. Corneal and ocular WA of a 6-mm pupil were measured and the root-mean-square (RMS) of the astigmatism, coma, spherical aberration (SA), and total higher-order aberrations (HOAs) were determined. During the 30-day period, the central cornea thinned in the horizontal and vertical meridians, whereas corneal thickening occurred in the temporal, nasal, and inferior mid-peripheries. In contrast, the cornea thinned in the mid-peripheral superior. There were significant increases in RMS for astigmatism, SA, coma, and positive horizontal coma during the study period. After OK, there were significant positive correlations between the midperipheral-central thickness change difference and the changes in corneal and ocular RMS of total HOAs and SA (r range: 0.281 to 0.492, POK caused unique changes in corneal thickness profiles at the vertical and horizontal meridians and increased corneal and ocular HOAs related to corneal reshaping.

  17. Nodal aberration theory applied to freeform surfaces

    Science.gov (United States)

    Fuerschbach, Kyle; Rolland, Jannick P.; Thompson, Kevin P.

    2014-12-01

    When new three-dimensional packages are developed for imaging optical systems, the rotational symmetry of the optical system is often broken, changing its imaging behavior and making the optical performance worse. A method to restore the performance is to use freeform optical surfaces that compensate directly the aberrations introduced from tilting and decentering the optical surfaces. In order to effectively optimize the shape of a freeform surface to restore optical functionality, it is helpful to understand the aberration effect the surface may induce. Using nodal aberration theory the aberration fields induced by a freeform surface in an optical system are explored. These theoretical predications are experimentally validated with the design and implementation of an aberration generating telescope.

  18. Cooperative scans

    NARCIS (Netherlands)

    M. Zukowski (Marcin); P.A. Boncz (Peter); M.L. Kersten (Martin)

    2004-01-01

    textabstractData mining, information retrieval and other application areas exhibit a query load with multiple concurrent queries touching a large fraction of a relation. This leads to individual query plans based on a table scan or large index scan. The implementation of this access path in most

  19. Understanding the structure of nanocatalysts with high resolution scanning/transmission electron microscopy

    International Nuclear Information System (INIS)

    Francis, L D; Rivas, J; José-Yacamán, M

    2014-01-01

    Nanomaterials including nanoparticles, nanowires and nanotubes play an important role in heterogeneous catalysis. Thanks to the rapid improvement of the electron microscopic techniques and with the advent of aberration corrected electron microscopy as well as theoretical methodologies, the potential effects induced by nanocatalysts are better understood than before by unravelling their atomic structure. A brief introduction to advanced electron microscopic techniques namely aberration corrected scanning transmission electron microscopy (Cs-STEM) is presented and subsequently two examples of nanocatalysts are considered in the present review. The first example will focus on the study of bimetallic/core-shell nanoalloys. In heterogeneous catalysis, catalysts containing two or more metals might show significantly different catalytic properties compared to the parent metals and thus are widely utilized in several catalytic reactions. Atom-by-atom insights of the nanoalloy based catalysts ex: Au-Pd will be described in the present review using a combination of advanced electron microscopic and spectroscopic techniques. A related example on the understanding of bimetallic clusters by HAADF-STEM will also be presented in addition to nanoparticles. In the second case understanding the structure of transition metal chalcogenide based nanocatalysts by HRTEM and aberration corrected STEM, for the case of MoS 2 will be discussed. MoS 2 -based catalysts serve as model catalysts and are employed in the hydrodesulphurisations (HDS) reactions in the removal of sulphur from gasoline and related petrochemical products. They have been studied in various forms including nanowires, nanotubes and nanoplates. Their structure, atomic insights and as a consequence elucidation of their corresponding catalytic activity are thus important

  20. Flow cytogenetics: progress toward chromosomal aberration detection

    International Nuclear Information System (INIS)

    Carrano, A.V.; Gray, J.W.; Van Dilla, M.A.

    1977-01-01

    Using clonal derivatives of the Chinese hamster M3-1 cell line, we demonstrate the potential of flow systems to karyotype homogeneous aberrations (aberrations which are identical and present in every cell) and to detect heterogeneous aberrations (aberrations which occur randomly in a population and are not identical in every cell). Flow cytometry (FCM) of ethidium bromide stained isolated chromosomes from clone 650A of the M3-1 cells distinguishes nine chromosome types from the fourteen present in the actual karyotype. X-irradiation of this parent 650A clone produced two sub-clones with an altered flow karyotype, that is, their FCM distributions were characterized by the addition of new peaks and alterations in area under existing peaks. From the relative DNA content and area for each peak, as determined by computer analysis, we predicted that each clone had undergone a reciprocal translocation involving chromosomes from two peaks. This prediction was confirmed by Giemsa-banding the metaphase cells. Heterogeneous aberrations are reflected in the flow karyotype as an increase in background, that is, an increase in area underlying the chromosome peaks. This increase is dose dependent but, as yet, the sample variability has been too large for quantitative analysis. Flow sorting of the valleys between chromosome peaks produces enriched fractions of aberrant chromosomes for visual analysis. These approaches are potentially applicable to the analysis of chromsomal aberrations induced by environmental contaminants

  1. [Aberrant bodily self in schizophrenia].

    Science.gov (United States)

    Maeda, Takaki; Mimura, Masaru

    2014-04-01

    Patients with schizophrenia often experience aberrant bodily self including depersonalization and cenesthopathy, especially in its prodromal and early stage. These symptoms are regarded as the beginning of self-disturbances (i.e. the core psychopathology of the illness). Thus, an understanding of schizophrenic bodily experiences could provide insight into the pathophysiology of schizophrenia. Recently, in the field of cognitive neuroscience, research on self-awareness during intentional actions has focused on examining sense of body ownership (SoO) and sense of agency (SoA). The most critical factor for the emergence of those higher-order senses of self is subject's intention for actions. Intentional signals could integrate multiple bodily sensory feedbacks during actions, and lead to develop a coherent sense of self. Empirical studies using behavioral and neuroimaging experiments have demonstrated that schizophrenic patients exhibit specific patterns of abnormal SoO and SoA. Thus, from a clinical standpoint, the detection of specific nature of schizophrenic bodily experiences could provide evidence for early diagnosis and intervention for schizophrenia.

  2. Diagnostic radiation and chromosome aberrations

    International Nuclear Information System (INIS)

    Patil, S.R.; Hecht, F.; Lubs, H.A.; Kimberling, W.; Brown, J.; Gerald, P.S.; Summitt, R.L.

    1977-01-01

    Some evidence is presented suggesting that diagnostic X-rays may be important in the origin of a new chromosomal abnormality other than Down syndrome. Chromosome analyses have been carried out on 4342 children, seven or eight years old. Maternal diagnostic irradiation in the year before conception and up to third lunar month of the index pregnancy was recorded, before the chromosome study began, together with a large amount of family and clinical data. Information on X-ray exposure was supplied by the mothers, s o radiation dosage could not be estimated. 21 children (including a pair of twins and a pair of siblings) born to 19 mothers had chromosomal aberrations. The mothers of six children with inherited translocations, rearrangements and XYY karyotypes were excluded, and 3 (23%) of the remaining 13 mothers had received abdominal and pelvic X-ray exposures. In the whole sample, however, only 6% of the mothers had diagnostic irradiation. Two of these mothers, aged sixteen and twenty, gave birth to a child each with de-novo autosomal translocations, and the third mother, aged thirty-two, had a child with a complex mosaicism involving one X chromosome. Although the sample size of the mothers with chromosomally abnormal children is small, the results are significant. (U.K.)

  3. Population spherical aberration: associations with ametropia, age, corneal curvature, and image quality

    Directory of Open Access Journals (Sweden)

    Kingston AC

    2013-05-01

    Full Text Available Amanda C Kingston,1,2 Ian G Cox11Bausch + Lomb, Rochester, NY, USA; 2Department of Biomedical Engineering, University of Rochester, Rochester, NY, USAPurpose: The aim of this analysis was to determine the total ocular wavefront aberration values of a large phakic population of physiologically normal, ametropic eyes, gathered under the same clinical protocol using the same diagnostic wavefront sensor.Materials and methods: Studies were conducted at multiple sites in Asia, North America, Europe, and Australia. A Bausch + Lomb Zywave II Wavefront Aberrometer (Rochester, NY, USA was used to measure the lower and higher order aberrations of each eye. Data analysis was conducted using linear regression analysis to determine the relationship between total spherical aberration, ametropia, age, corneal curvature, and image quality.Results: Linear regression analysis showed no correlation (r = 0.0207, P = 0.4874 between degree of ametropia and the amount of spherical aberration. There was also no correlation when the population was stratified into myopic and hyperopic refractive groups (rm = 0.0529, Pm = 0.0804 and rh = 0.1572, Ph = 0.2754. There was a statistically significant and weak positive correlation (r = 0.1962, P < 0.001 between age and the amount of spherical aberration measured in the eye; spherical aberration became more positive with increasing age. Also, there was a statistically significant and moderately positive correlation (r = 0.3611, P < 0.001 with steepness of corneal curvature; spherical aberration became more positive with increasing power of the anterior corneal surface. Assessment of image quality using optical design software (Zemax™, Bellevue, WA, USA showed that there was an overall benefit in correcting the average spherical aberration of this population.Conclusion: Analysis of this dataset provides insights into the inherent spherical aberration of a typical phakic, pre-presbyopic, population and provides the ability to

  4. Aberration-Coreected Electron Microscopy at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Zhu,Y.; Wall, J.

    2008-04-01

    The last decade witnessed the rapid development and implementation of aberration correction in electron optics, realizing a more-than-70-year-old dream of aberration-free electron microscopy with a spatial resolution below one angstrom [1-9]. With sophisticated aberration correctors, modern electron microscopes now can reveal local structural information unavailable with neutrons and x-rays, such as the local arrangement of atoms, order/disorder, electronic inhomogeneity, bonding states, spin configuration, quantum confinement, and symmetry breaking [10-17]. Aberration correction through multipole-based correctors, as well as the associated improved stability in accelerating voltage, lens supplies, and goniometers in electron microscopes now enables medium-voltage (200-300kV) microscopes to achieve image resolution at or below 0.1nm. Aberration correction not only improves the instrument's spatial resolution but, equally importantly, allows larger objective lens pole-piece gaps to be employed thus realizing the potential of the instrument as a nanoscale property-measurement tool. That is, while retaining high spatial resolution, we can use various sample stages to observe the materials response under various temperature, electric- and magnetic- fields, and atmospheric environments. Such capabilities afford tremendous opportunities to tackle challenging science and technology issues in physics, chemistry, materials science, and biology. The research goal of the electron microscopy group at the Dept. of Condensed Matter Physics and Materials Science and the Center for Functional Nanomaterials, as well as the Institute for Advanced Electron Microscopy, Brookhaven National Laboratory (BNL), is to elucidate the microscopic origin of the physical- and chemical-behavior of materials, and the role of individual, or groups of atoms, especially in their native functional environments. We plan to accomplish this by developing and implementing various quantitative

  5. The prevalence of chromosomal aberrations associated with myelodysplastic syndromes in China.

    Science.gov (United States)

    Hu, Qinyong; Chu, Yuxin; Song, Qibin; Yao, Yi; Yang, Weihong; Huang, Shiang

    2016-08-01

    This study aims to investigate the prevalence and distribution of diverse chromosomal aberrations associated with myelodysplastic syndromes (MDS) in China. Bone marrow samples were collected from multiple cities in China. Metaphase cytogenetic (MC) analysis and fluorescence in situ hybridization (FISH) were initially used to test chromosomal lesions. Affymetrix CytoScan 750 K genechip platform performed a genome-wide detection of chromosomal aberrations. Chromosomal gain was identified in 76 patients; the most prevalent was trisomy 8(17.9 %). New chromosomal gain was detected on chromosome 9, 19p, and X. Chromosomal loss was detected in 101 patients. The most frequent was loss 5q (21.0 %). Some loss and gain were not identified by MC or FISH but identified by genechip. UPD was solely identified by genechip in 51 patients; the most prevalent were UPD 7q (4.94 %) and UPD 17p (4.32 %). Furthermore, complex chromosomal aberrations were detected in 56 patients. In conclusion, Affymetrix CytoScan 750 K genechip was more precise than MC and FISH in detection of cryptic chromosomal aberrations relevant to MDS. Analysis of the prevalence and distribution of diverse chromosomal aberrations in China may improve strategies for MDS diagnosis and therapies.

  6. Bone Scan

    Science.gov (United States)

    ... posts Join Mayo Clinic Connect Bone scan About Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  7. MRI Scans

    Science.gov (United States)

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from ...

  8. Spherical aberration compensation method for long focal-length measurement based on Talbot interferometry

    Science.gov (United States)

    Luo, Yupeng; Huang, Xiao; Bai, Jian; Du, Juan; Liu, Qun; Luo, Yujie; Luo, Jia

    2017-08-01

    Large-aperture and long focal-length lens is widely used in high energy laser system. The method based on Talbot interferometry is a reliable method to measure the focal length of such elements. By employing divergent beam and two gratings of different periods, this method could realize full-aperture measurement, higher accuracy and better repeatability. However, it does not take into account the spherical aberration of the measured lens resulting in the moiré fringes bending, which will introduce measurement error. Furthermore, in long-focal measurement with divergent beam, this error is an important factor affecting the measurement accuracy. In this paper, we propose a new spherical aberration compensation method, which could significantly reduce the measurement error. Characterized by central-symmetric scanning window, the proposed method is based on the relationship between spherical aberration and the lens aperture. Angle data of moiré fringes in each scanning window is retrieved by Fourier analysis and statistically fitted to estimate a globally optimum value for spherical-aberration-free focal length calculation. Simulation and experiment have been carried out. Compared to the previous work, the proposed method is able to reduce the relative measurement error by 50%. The effect of scanning window size and shift step length on the results is also discussed.

  9. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    Kritchman, E.M.

    1979-01-01

    A new linear convex Fresnel lens with its groove side down is described. The design philosophy is similar to the highly concentrating two focal Fresnel lens but including a correction for chromatic aberration. A solar concentration ratio as high as 80 is achieved. For wide acceptance angles the concentration nears the theoretical maximum. (author)

  10. Aberrant Right Subclavian Artery: A Life-threatening Anomaly that should be considered during Esophagectomy.

    Science.gov (United States)

    Mahmodlou, Rahim; Sepehrvand, Nariman; Hatami, Sanaz

    2014-01-01

    Aberrant right subclavian artery (ARSA) is a rare anomaly, in which the right subclavian artery arises directly from the aortic arch instead of originating from the brachiocephalic artery. This anomaly should be taken into consideration during surgical procedures around esophagus, such as esophagectomy. Any unintentional injury of this artery during surgical procedures could be extremely life threatening. A 56-year-old woman presented with dysphagia, with concurrent aberrant subclavian artery and esophageal cancer. The transhiatal esophagectomy was performed successfully since the anomaly was preoperatively diagnosed using computed tomography scan. The presence of ARSA during esophagectomy may be challenging, but if diagnosed preoperatively, the precise and diligent dissection of the retroesophageal space during esophagectomy, may prevent any injury to the aberrant artery and consequent complications.

  11. Scanning table

    CERN Multimedia

    1960-01-01

    Before the invention of wire chambers, particles tracks were analysed on scanning tables like this one. Today, the process is electronic and much faster. Bubble chamber film - currently available - (links can be found below) was used for this analysis of the particle tracks.

  12. Computational genes: a tool for molecular diagnosis and therapy of aberrant mutational phenotype

    Directory of Open Access Journals (Sweden)

    Ignatova Zoya

    2007-09-01

    Full Text Available Abstract Background A finite state machine manipulating information-carrying DNA strands can be used to perform autonomous molecular-scale computations at the cellular level. Results We propose a new finite state machine able to detect and correct aberrant molecular phenotype given by mutated genetic transcripts. The aberrant mutations trigger a cascade reaction: specific molecular markers as input are released and induce a spontaneous self-assembly of a wild type protein or peptide, while the mutational disease phenotype is silenced. We experimentally demostrated in in vitro translation system that a viable protein can be autonomously assembled. Conclusion Our work demostrates the basic principles of computational genes and particularly, their potential to detect mutations, and as a response thereafter administer an output that suppresses the aberrant disease phenotype and/or restores the lost physiological function.

  13. Measuring aberrations in the rat brain by coherence-gated wavefront sensing using a Linnik interferometer.

    Science.gov (United States)

    Wang, Jinyu; Léger, Jean-François; Binding, Jonas; Boccara, A Claude; Gigan, Sylvain; Bourdieu, Laurent

    2012-10-01

    Aberrations limit the resolution, signal intensity and achievable imaging depth in microscopy. Coherence-gated wavefront sensing (CGWS) allows the fast measurement of aberrations in scattering samples and therefore the implementation of adaptive corrections. However, CGWS has been demonstrated so far only in weakly scattering samples. We designed a new CGWS scheme based on a Linnik interferometer and a SLED light source, which is able to compensate dispersion automatically and can be implemented on any microscope. In the highly scattering rat brain tissue, where multiply scattered photons falling within the temporal gate of the CGWS can no longer be neglected, we have measured known defocus and spherical aberrations up to a depth of 400 µm.

  14. High resolution melting for mutation scanning of TP53 exons 5–8

    International Nuclear Information System (INIS)

    Krypuy, Michael; Dobrovic, Alexander; Ahmed, Ahmed Ashour; Etemadmoghadam, Dariush; Hyland, Sarah J; Australian Ovarian Cancer Study Group; Fazio, Anna de; Fox, Stephen B; Brenton, James D; Bowtell, David D

    2007-01-01

    p53 is commonly inactivated by mutations in the DNA-binding domain in a wide range of cancers. As mutant p53 often influences response to therapy, effective and rapid methods to scan for mutations in TP53 are likely to be of clinical value. We therefore evaluated the use of high resolution melting (HRM) as a rapid mutation scanning tool for TP53 in tumour samples. We designed PCR amplicons for HRM mutation scanning of TP53 exons 5 to 8 and tested them with DNA from cell lines hemizygous or homozygous for known mutations. We assessed the sensitivity of each PCR amplicon using dilutions of cell line DNA in normal wild-type DNA. We then performed a blinded assessment on ovarian tumour DNA samples that had been previously sequenced for mutations in TP53 to assess the sensitivity and positive predictive value of the HRM technique. We also performed HRM analysis on breast tumour DNA samples with unknown TP53 mutation status. One cell line mutation was not readily observed when exon 5 was amplified. As exon 5 contained multiple melting domains, we divided the exon into two amplicons for further screening. Sequence changes were also introduced into some of the primers to improve the melting characteristics of the amplicon. Aberrant HRM curves indicative of TP53 mutations were observed for each of the samples in the ovarian tumour DNA panel. Comparison of the HRM results with the sequencing results revealed that each mutation was detected by HRM in the correct exon. For the breast tumour panel, we detected seven aberrant melt profiles by HRM and subsequent sequencing confirmed the presence of these and no other mutations in the predicted exons. HRM is an effective technique for simple and rapid scanning of TP53 mutations that can markedly reduce the amount of sequencing required in mutational studies of TP53

  15. Effects of chalazion excision on ocular aberrations.

    Science.gov (United States)

    Sabermoghaddam, Ali A; Zarei-Ghanavati, Siamak; Abrishami, Mojtaba

    2013-06-01

    The goal of this study was to compare higher-order aberrations before and after upper lid chalazion excision. Fourteen eyes from 12 patients (8 females, mean age: 28.7 ± 2.7 years) with upper lid chalazion were enrolled in this prospective interventional case series. Chalazia were excised by standard transconjunctival vertical incision. Ocular aberrations were evaluated by aberrometry (ZyWave) before and 2 months after chalazion excision. Root mean square of total higher-order aberrations decreased from 0.67 ± 0.12 to 0.43 ± 0.15 μm (P = 0.012) after excision. The root mean square of Zernike orders in the vertical and horizontal trefoil and horizontal coma were decreased after excision. Orbscan IIz tomography showed a statistically significant decrease in 5 mm zone irregularity (P = 0.027) and an increase in minimum simulated keratometry after surgery (P = 0.046). Chalazion increases higher-order aberrations, as measured by the Hartmann-Shack aberrometer, which could affect the preoperative evaluation and results of refractive surgery, especially wavefront-guided approaches. Chalazion excision could reduce ocular aberrations and is recommended before refractive surgeries.

  16. Chromosomal aberrations induced by alpha particles

    International Nuclear Information System (INIS)

    Guerrero C, C.; Brena V, M.

    2005-01-01

    The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

  17. Electrostatic axisymmetric mirror with removable spherical aberration

    International Nuclear Information System (INIS)

    Birmuzaev, S.B.; Serikbaeva, G.S.; Hizirova, M.A.

    1999-01-01

    The electrostatic axisymmetric mirror, assembled from three coaxial cylinders with an equal diameter d and under the potential v1, v2 and v3, was computed. The proportions of geometrical and electric parameters of the mirror, with which the spherical 3-order aberration may be eliminated, were determined. The computation outcomes of the case, when the focal power of the mirror is enough large and the object plane in the focus is out of its field, are presented (Fig. 1 - potentials proportion that makes elimination of the spherical aberration possible; Fig. 2 - the focus coordinates when the spherical aberration is eliminated). The geometrical values are presented by d, and the electric ones are presented by v1. The figures on the curves present a length of the second (middle) electrode. The zero point is located in the middle of the gap between the first and second electrodes The investigated mirror may be used as a lens for the transmission electron microscope

  18. Exaggerated translation causes synaptic and behavioural aberrations associated with autism.

    Science.gov (United States)

    Santini, Emanuela; Huynh, Thu N; MacAskill, Andrew F; Carter, Adam G; Pierre, Philippe; Ruggero, Davide; Kaphzan, Hanoch; Klann, Eric

    2013-01-17

    Autism spectrum disorders (ASDs) are an early onset, heterogeneous group of heritable neuropsychiatric disorders with symptoms that include deficits in social interaction skills, impaired communication abilities, and ritualistic-like repetitive behaviours. One of the hypotheses for a common molecular mechanism underlying ASDs is altered translational control resulting in exaggerated protein synthesis. Genetic variants in chromosome 4q, which contains the EIF4E locus, have been described in patients with autism. Importantly, a rare single nucleotide polymorphism has been identified in autism that is associated with increased promoter activity in the EIF4E gene. Here we show that genetically increasing the levels of eukaryotic translation initiation factor 4E (eIF4E) in mice results in exaggerated cap-dependent translation and aberrant behaviours reminiscent of autism, including repetitive and perseverative behaviours and social interaction deficits. Moreover, these autistic-like behaviours are accompanied by synaptic pathophysiology in the medial prefrontal cortex, striatum and hippocampus. The autistic-like behaviours displayed by the eIF4E-transgenic mice are corrected by intracerebroventricular infusions of the cap-dependent translation inhibitor 4EGI-1. Our findings demonstrate a causal relationship between exaggerated cap-dependent translation, synaptic dysfunction and aberrant behaviours associated with autism.

  19. Scanning holograms

    International Nuclear Information System (INIS)

    Natali, S.

    1984-01-01

    This chapter reports on the scanning of 1000 holograms taken in HOBC at CERN. Each hologram is triggered by an interaction in the chamber, the primary particles being pions at 340 GeV/c. The aim of the experiment is the study of charm production. The holograms, recorded on 50 mm film with the ''in line'' technique, can be analyzed by shining a parallel expanded laser beam through the film, obtaining immediately above it the real image of the chamber which can then be scanned and measured with a technique half way between emulsions and bubble chambers. The results indicate that holograms can be analyzed as quickly and reliably as in other visual techniques and that to them is open the same order of magnitude of large scale experiments

  20. Author Correction

    DEFF Research Database (Denmark)

    Grundle, D S; Löscher, C R; Krahmann, G

    2018-01-01

    A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.......A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper....

  1. Bone scan in mastocytosis: case report

    International Nuclear Information System (INIS)

    Sy, W.M.; Bonventre, M.V.; Camera, A.

    1976-01-01

    A 45-year-old man with well-documented systemic mastocytosis showed generalized symmetric increased activity on bone imaging. These scan findings are grossly indistinguishable from those of patients with renal osteodystrophy or secondary hyperparathyroidism. The images of the hands, however, failed to show the changes observed in secondary hyperparathyroidism. The mechanism for this intense activity is thought to be due to aberrant new-bone formation

  2. A collection of Schottky-scan notes

    International Nuclear Information System (INIS)

    Sabersky, A.P.

    1980-10-01

    This paper is a republication of ISR-RF notes and performance reports on work done in 1974-1975. The original notes have been edited, corrected and, in most cases, shortened. Discussed in this note are the following topics: noise, errors and the Schottky scan; speeding up the Schottky scan; Schottky markers and fast Schottky scans; and some engineering aspects of the fast Schottky scan

  3. Quality control systems for aberrant mRNAs induced by aberrant translation elongation and termination.

    Science.gov (United States)

    Inada, Toshifumi

    2013-01-01

    RNA processing is an essential gene expression step and plays a crucial role to achieve diversity of gene products in eukaryotes. Various aberrant mRNAs transiently produced during RNA processing reactions are recognized and eliminated by specific quality control systems. It has been demonstrated that these mRNA quality control systems stimulate the degradation of aberrant mRNA to prevent the potentially harmful products derived from aberrant mRNAs. Recent studies on quality control systems induced by abnormal translation elongation and termination have revealed that both aberrant mRNAs and proteins are subjected to rapid degradation. In NonStop Decay (NSD) quality control system, a poly(A) tail of nonstop mRNA is translated and the synthesis of poly-lysine sequence results in translation arrest followed by co-translational degradation of aberrant nonstop protein. In No-Go Decay (NGD) quality control system, the specific amino acid sequences of the nascent polypeptide induce ribosome stalling, and the arrest products are ubiquitinated and rapidly degraded by the proteasome. In Nonfunctional rRNA Decay (NRD) quality control system, aberrant ribosomes composed of nonfunctional ribosomal RNAs are also eliminated when aberrant translation elongation complexes are formed on mRNA. I describe recent progresses on the mechanisms of quality control systems and the relationships between quality control systems. This article is part of a Special issue entitled: RNA Decay mechanisms. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Unsupervised identification of cone photoreceptors in non-confocal adaptive optics scanning light ophthalmoscope images.

    Science.gov (United States)

    Bergeles, Christos; Dubis, Adam M; Davidson, Benjamin; Kasilian, Melissa; Kalitzeos, Angelos; Carroll, Joseph; Dubra, Alfredo; Michaelides, Michel; Ourselin, Sebastien

    2017-06-01

    Precise measurements of photoreceptor numerosity and spatial arrangement are promising biomarkers for the early detection of retinal pathologies and may be valuable in the evaluation of retinal therapies. Adaptive optics scanning light ophthalmoscopy (AOSLO) is a method of imaging that corrects for aberrations of the eye to acquire high-resolution images that reveal the photoreceptor mosaic. These images are typically graded manually by experienced observers, obviating the robust, large-scale use of the technology. This paper addresses unsupervised automated detection of cones in non-confocal, split-detection AOSLO images. Our algorithm leverages the appearance of split-detection images to create a cone model that is used for classification. Results show that it compares favorably to the state-of-the-art, both for images of healthy retinas and for images from patients affected by Stargardt disease. The algorithm presented also compares well to manual annotation while excelling in speed.

  5. In-situ environmental (scanning) transmission electron microscopy of catalysts at the atomic level

    International Nuclear Information System (INIS)

    Gai, P L; Boyes, E D

    2014-01-01

    Observing reacting single atoms on the solid catalyst surfaces under controlled reaction conditions is a key goal in understanding and controlling heterogeneous catalytic reactions. In-situ real time aberration corrected environmental (scanning) transmission electron microscopy (E(S)TEM permit the direct imaging of dynamic surface and sub-surface structures of reacting catalysts. In this paper in-situ AC ETEM and AC ESTEM studies under controlled reaction environments of oxide catalysts and supported metal nanocatalysts important in chemical industry are presented. They provide the direct evidence of dynamic processes at the oxide catalyst surface at the atomic scale and single atom dynamics in catalytic reactions. The ESTEM studies of single atom dynamics in controlled reaction environments show that nanoparticles act as reservoirs of ad-atoms. The results have important implications in catalysis and nanoparticle studies

  6. Geometrical Aberration Suppression for Large Aperture Sub-THz Lenses

    Science.gov (United States)

    Rachon, M.; Liebert, K.; Siemion, A.; Bomba, J.; Sobczyk, A.; Knap, W.; Coquillat, D.; Suszek, J.; Sypek, M.

    2017-03-01

    Advanced THz setups require high performance optical elements with large numerical apertures and small focal lengths. This is due to the high absorption of humid air and relatively low efficiency of commercially available detectors. Here, we propose a new type of double-sided sub-THz diffractive optical element with suppressed geometrical aberration for narrowband applications (0.3 THz). One side of the element is designed as thin structure in non-paraxial approach which is the exact method, but only for ideally flat elements. The second side will compensate phase distribution differences between ideal thin structure and real volume one. The computer-aided optimization algorithm is performed to design an additional phase distribution of correcting layer assuming volume designing of the first side of the element. The experimental evaluation of the proposed diffractive component created by 3D printing technique shows almost two times larger performance in comparison with uncorrected basic diffractive lens.

  7. Correct Models

    OpenAIRE

    Blacher, René

    2010-01-01

    Ce rapport complete les deux rapports précédents et apporte une explication plus simple aux résultats précédents : à savoir la preuve que les suites obtenues sont aléatoires.; In previous reports, we have show how to transform a text $y_n$ in a random sequence by using functions of Fibonacci $T_q$. Now, in this report, we obtain a clearer result by proving that $T_q(y_n)$ has the IID model as correct model. But, it is necessary to define correctly a correct model. Then, we study also this pro...

  8. Chromosomal aberrations induced by Markhamia tomentosa (Benth ...

    African Journals Online (AJOL)

    Markhamia tomentosa (Benth.) K. Schum. Ex Engl. (Bignoniaceae) is used traditionally in the treatment of pain, oedema, pulmonary troubles and cancer. The genotoxic and cytotoxic effects of the ethanolic extract of the leaves of M. tomentosa was investigated using the Allium cepa root chromosomal aberration assay.

  9. Anti-forensics of chromatic aberration

    Science.gov (United States)

    Mayer, Owen; Stamm, Matthew C.

    2015-03-01

    Over the past decade, a number of information forensic techniques have been developed to identify digital image manipulation and falsification. Recent research has shown, however, that an intelligent forger can use anti-forensic countermeasures to disguise their forgeries. In this paper, an anti-forensic technique is proposed to falsify the lateral chromatic aberration present in a digital image. Lateral chromatic aberration corresponds to the relative contraction or expansion between an image's color channels that occurs due to a lens's inability to focus all wavelengths of light on the same point. Previous work has used localized inconsistencies in an image's chromatic aberration to expose cut-and-paste image forgeries. The anti-forensic technique presented in this paper operates by estimating the expected lateral chromatic aberration at an image location, then removing deviations from this estimate caused by tampering or falsification. Experimental results are presented that demonstrate that our anti-forensic technique can be used to effectively disguise evidence of an image forgery.

  10. Contralateral eye surgery with adjustable suture for management of third nerve palsy with aberrant regeneration

    Directory of Open Access Journals (Sweden)

    Phuong Thi Thanh Nguyen

    2017-01-01

    Full Text Available Aberrant regeneration of the third nerve following its palsy is commonly seen after trauma and compressive lesions. This phenomenon is thought to result due to misdirection of the regenerating axons. Surgical management is a great challenge in the third nerve palsy owing to multiple muscle involvement and is often accompanied by ptosis and poor Bell's phenomenon. We present a case of a 27-year-old male who developed isolated complete third nerve palsy of the left eye following head trauma. Features of aberrant regeneration were seen after 6 months, namely, inverse Duane's sign and Pseudo-Von Graefe's sign. He underwent recess-resect procedure in the unaffected eye with adjustable suture technique which not only corrected the deviation but also the ptosis by utilizing the oculomotor synkinesis. Thus, contralateral eye surgery combined with adjustable suture technique resulted in an accurate alignment of the eye and obviated the need for ptosis correction.

  11. Aberration-accounting calibration for 3D single-molecule localization microscopy

    Science.gov (United States)

    Cabriel, Clément; Bourg, Nicolas; Dupuis, Guillaume; Lévêque-Fort, Sandrine

    2018-01-01

    We propose a straightforward sample-based technique to calibrate the axial detection in 3D single molecule localization microscopy (SMLM). Using microspheres coated with fluorescent molecules, the calibration curves of PSF-shaping- or intensity-based measurements can be obtained for any required depth range from a few hundreds of nanometers to several tens of microns. This experimental method takes into account the effect of the spherical aberration without requiring computational correction.

  12. Three-dimensional STED microscopy of aberrating tissue using dual adaptive optics.

    Science.gov (United States)

    Patton, Brian R; Burke, Daniel; Owald, David; Gould, Travis J; Bewersdorf, Joerg; Booth, Martin J

    2016-04-18

    When imaging through tissue, the optical inhomogeneities of the sample generate aberrations that can prevent effective Stimulated Emission Depletion (STED) imaging. This is particularly problematic for 3D-enhanced STED. We present here an adaptive optics implementation that incorporates two adaptive optic elements to enable correction in all beam paths, allowing performance improvement in thick tissue samples. We use this to demonstrate 3D STED imaging of complex structures in Drosophila melanogaster brains.

  13. The prediction of spherical aberration with schematic eyes.

    Science.gov (United States)

    Liou, H L; Brennan, N A

    1996-07-01

    Many model eyes have been proposed; they differ in optical characteristics and therefore have different aberrations and image quality. In predicting the visual performance of the eye, we are most concerned with the central foveal vision. Spherical aberration is the only on-axis monochromatic aberration and can be used as a criterion to assess the degree of resemblance of eye models to the human eye. We reviewed and compiled experimental values of the spherical aberration of the eye, calculated the spherical aberration of several different categories of model eyes and compared the calculated results to the experimental data. Results show an over-estimation of spherical aberration by all models, the finite schematic eyes predicting values of spherical aberration closest to the experimental data. Current model eyes do not predict the average experimental values of the spherical aberration of the eye. A new model eye satisfying this assessment criterion is required for investigations of the visual performance of the eye.

  14. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan and uptake uses ... the Thyroid Scan and Uptake? What is a Thyroid Scan and Uptake? A thyroid scan is a ...

  15. Aberration-sensing and wavefront-guided laser in situ keratomileusis: management of decentered ablation.

    Science.gov (United States)

    Mrochen, Michael; Krueger, Ronald R; Bueeler, Michael; Seiler, Theo

    2002-01-01

    To clarify the feasibility of aberration-sensing and wavefront-guided laser in situ keratomileusis (LASIK) to manage grossly decentered ablation and to discuss the limitations of the technology. Three patients with previous decentrations of the ablation zone between 1.5 to 2.0 mm were scheduled for wavefront-guided LASIK. All patients reported monocular diplopia and halos. Wavefront aberrations were measured with a Tscherning-type aberrometer. Laser ablation was done with a WaveLight Allegretto in a one-step procedure with ablation profiles calculated only from the individual wavefront map. Decentrations were determined from corneal topography. Three months after surgery, patient WM and patient SU had gained uncorrected and best spectacle-corrected visual acuity. The root mean square-wavefront error decreased up to 61% and 33%, respectively, for total and higher order aberrations (Zernike modes of 3rd order and higher). There was significant enlargement of the optical zone determined by corneal topography, and both patients no longer reported diplopia and halos at 3 months postoperatively. The optical aberration of the third patient (RE), after a 5.00-D overcorrection with a 2-mm decentration, was too high for aberration-sensing; retinal images obtained from the wavefront device were too smeared and not of sufficient contrast. In addition, this patient had a residual corneal thickness of 416 microm and thus wavefront-guided LASIK was not done. Wavefront-guided LASIK offers a new way of managing grossly decentered laser ablations. Unfortunately, there are still patients who have aberrations too large for wavefront sensing or with other clinical limitations such as a residual corneal thickness too thin for further treatment.

  16. Chromatic aberration and the roles of double-opponent and color-luminance neurons in color vision

    NARCIS (Netherlands)

    Vladusich, Tony

    How does the visual cortex encode color? I summarize a theory in which cortical double-opponent color neurons perform a role in color constancy and a complementary set of color-luminance neurons function to selectively correct for color fringes induced by chromatic aberration in the eye. The theory

  17. Expressions for third-order aberration theory for holographic images

    Indian Academy of Sciences (India)

    established aberration theory in the case of conventional optical elements. It was Meier. [1] who pioneered third-order aberration theory for applications in holography. There are reports in the literature contrary to Meier's results, e.g.,. (i) Smith [2] recalculated third-order aberration on the lines of Meier and tabulated his.

  18. Aberrant intestinal microbiota in individuals with prediabetes

    DEFF Research Database (Denmark)

    Allin, Kristine H.; Tremaroli, Valentina; Caesar, Robert

    2018-01-01

    Aims/hypothesis: Individuals with type 2 diabetes have aberrant intestinal microbiota. However, recent studies suggest that metformin alters the composition and functional potential of gut microbiota, thereby interfering with the diabetes-related microbial signatures. We tested whether specific gut...... microbiota profiles are associated with prediabetes (defined as fasting plasma glucose of 6.1–7.0 mmol/l or HbA1c of 42–48 mmol/mol [6.0–6.5%]) and a range of clinical biomarkers of poor metabolic health. Methods: In the present case–control study, we analysed the gut microbiota of 134 Danish adults...... impaired glucose regulation in recipient mice. Conclusions/interpretation: Collectively, our data show that individuals with prediabetes have aberrant intestinal microbiota characterised by a decreased abundance of the genus Clostridium and the mucin-degrading bacterium A. muciniphila. Our findings...

  19. Aberrant PO2 values in proficiency testing.

    Science.gov (United States)

    Fonzi, C E; Clausen, J L; Mahoney, J

    1993-03-01

    We prospectively determined the frequency of aberrant vials of fluorocarbon/buffer used for proficiency testing of measurements of pH, PCO2, and PO2, using 20 duplicate vials from 12 lots of fluorocarbon/buffer and two arterial blood gas analyzers in eight reference laboratories. We defined aberrant vials as vials for which both duplicate measurements differed from the mean value of repeated measurements for the specific instrument (for each lot of testing materials) by > 0.04 for pH, > 10% of the mean or 3.0 mm Hg, whichever was greater, for PCO2; or > 10% of the mean or 6 mm Hg, whichever was greater, for PO2. Four of 1620 vials (0.25%) were aberrant, all based on PO2 measurements (range of mean values: pH, 7.181-7.631; PCO2, 12.7-65.9; PO2, 32.5-150.1) were 0.0055 for pH, 0.67 mm Hg for PCO2, and 1.65 mm Hg for PO2. Deliberate contamination of the fluorocarbon emulsion with room air, as might occur during sampling from the vial, indicated that only minor increases in PO2 (e.g., 1.0 mm Hg at PO2 of 56 mm Hg) occur when samples are aspirated. Larger increases in PO2 (mean 7.1 mm Hg at a PO2 of 66 mm Hg) occurred when the syringe samples were contaminated with room air. We conclude that isolated aberrant measurements of PO2 in blood gas proficiency testing attributable to vial contents can occur, but the frequency is very low.

  20. Assessing the construct validity of aberrant salience

    Directory of Open Access Journals (Sweden)

    Kristin Schmidt

    2009-12-01

    Full Text Available We sought to validate the psychometric properties of a recently developed paradigm that aims to measure salience attribution processes proposed to contribute to positive psychotic symptoms, the Salience Attribution Test (SAT. The “aberrant salience” measure from the SAT showed good face validity in previous results, with elevated scores both in high-schizotypy individuals, and in patients with schizophrenia suffering from delusions. Exploring the construct validity of salience attribution variables derived from the SAT is important, since other factors, including latent inhibition/learned irrelevance, attention, probabilistic reward learning, sensitivity to probability, general cognitive ability and working memory could influence these measures. Fifty healthy participants completed schizotypy scales, the SAT, a learned irrelevance task, and a number of other cognitive tasks tapping into potentially confounding processes. Behavioural measures of interest from each task were entered into a principal components analysis, which yielded a five-factor structure accounting for ~75% percent of the variance in behaviour. Implicit aberrant salience was found to load onto its own factor, which was associated with elevated “Introvertive Anhedonia” schizotypy, replicating our previous finding. Learned irrelevance loaded onto a separate factor, which also included implicit adaptive salience, but was not associated with schizotypy. Explicit adaptive and aberrant salience, along with a measure of probabilistic learning, loaded onto a further factor, though this also did not correlate with schizotypy. These results suggest that the measures of learned irrelevance and implicit adaptive salience might be based on similar underlying processes, which are dissociable both from implicit aberrant salience and explicit measures of salience.

  1. The aberrant retroesophageal right subclavian artery.

    Science.gov (United States)

    Seres-Sturm, M; Maros, T N; Seres-Sturm, L

    1985-01-01

    Two cases with arteria lusoria were found at 278 routine dissections. These arteria arise as the last branches of the aortic arch and have a retroesophageal position. At the crossing point, the esophagus narrows due to the groove caused by the artery. The appearance of this malposition is the consequence of the perturbation in the organo-genesis of the right dorsal aorta and fourth branchial artery. The aberration can lead to disphagia lusoria.

  2. Publisher Correction

    DEFF Research Database (Denmark)

    Flachsbart, Friederike; Dose, Janina; Gentschew, Liljana

    2018-01-01

    The original version of this Article contained an error in the spelling of the author Robert Häsler, which was incorrectly given as Robert Häesler. This has now been corrected in both the PDF and HTML versions of the Article....

  3. Publisher Correction

    DEFF Research Database (Denmark)

    Stokholm, Jakob; Blaser, Martin J.; Thorsen, Jonathan

    2018-01-01

    The originally published version of this Article contained an incorrect version of Figure 3 that was introduced following peer review and inadvertently not corrected during the production process. Both versions contain the same set of abundance data, but the incorrect version has the children...

  4. Chromatin Folding, Fragile Sites, and Chromosome Aberrations Induced by Low- and High- LET Radiation

    Science.gov (United States)

    Zhang, Ye; Cox, Bradley; Asaithamby, Aroumougame; Chen, David J.; Wu, Honglu

    2013-01-01

    We previously demonstrated non-random distributions of breaks involved in chromosome aberrations induced by low- and high-LET radiation. To investigate the factors contributing to the break point distribution in radiation-induced chromosome aberrations, human epithelial cells were fixed in G1 phase. Interphase chromosomes were hybridized with a multicolor banding in situ hybridization (mBAND) probe for chromosome 3 which distinguishes six regions of the chromosome in separate colors. After the images were captured with a laser scanning confocal microscope, the 3-dimensional structure of interphase chromosome 3 was reconstructed at multimega base pair scale. Specific locations of the chromosome, in interphase, were also analyzed with bacterial artificial chromosome (BAC) probes. Both mBAND and BAC studies revealed non-random folding of chromatin in interphase, and suggested association of interphase chromatin folding to the radiation-induced chromosome aberration hotspots. We further investigated the distribution of genes, as well as the distribution of breaks found in tumor cells. Comparisons of these distributions to the radiation hotspots showed that some of the radiation hotspots coincide with the frequent breaks found in solid tumors and with the fragile sites for other environmental toxins. Our results suggest that multiple factors, including the chromatin structure and the gene distribution, can contribute to radiation-induced chromosome aberrations.

  5. Broadband focal plane wavefront control of amplitude and phase aberrations

    Science.gov (United States)

    Groff, Tyler D.; Kasdin, N. Jeremy; Carlotti, Alexis; Riggs, A. J. Eldorado

    2012-09-01

    The Stroke Minimization algorithm developed at the Princeton High Contrast Imaging Laboratory has proven symmetric dark hole generation using minimal stroke on two deformable mirrors (DM) in series. The windowed approach to Stroke Minimization has proven symmetric dark holes over small bandwidths by using three wavelengths to define the bandwidth of correction in the optimization problem. We address the relationship of amplitude and phase aberrations with wavelength, how this changes with multiple DMs, and the implications for simultaneously correcting both to achieve symmetric dark holes. Operating Stroke Minimization in the windowed configuration requires multiple wavelength estimates. To save on exposures, a single estimate is extrapolated to bounding wavelengths using the established relationship in wavelength to produce multiple estimates of the image plane electric field. Here we demonstrate better performance by improving this extrapolation of the estimate to other wavelengths. The accuracy of the functional relationship will ultimately bound the achievable bandwidth, therefore as a metric these results are also compared to estimating each wavelength separately. In addition to these algorithm improvements, we also discuss a laboratory upgrade and how it can better simulate broadband starlight. We also discuss the possibility of leveraging two DMs in series to directly estimate the electric field over a narrow bandwidth and the challenges associated with it.

  6. Aberrant phenotypes in peripheral T cell lymphomas.

    Science.gov (United States)

    Hastrup, N; Ralfkiaer, E; Pallesen, G

    1989-01-01

    Seventy six peripheral T cell lymphomas were examined immunohistologically to test their reactivity with a panel of monoclonal antibodies against 11 T cell associated antigens (CD1-8, CD27, UCHL1, and the T cell antigen receptor). Sixty two (82%) lymphomas showed aberrant phenotypes, and four main categories were distinguished as follows: (i) lack of one or several pan-T cell antigens (49, 64% of the cases); (ii) loss of both the CD4 and CD8 antigens (11, 15% of the cases); (iii) coexpression of the CD4 and CD8 antigens (13, 17% of the cases); and (iv) expression of the CD1 antigen (eight, 11% of the cases). No correlation was seen between the occurrence of aberrant phenotypes and the histological subtype. It is concluded that the demonstration of an aberrant phenotype is a valuable supplement to histological assessment in the diagnosis of peripheral T cell lymphomas. It is recommended that the panel of monoclonal antibodies against T cell differentiation antigens should be fairly large, as apparently any antigen may be lost in the process of malignant transformation. Images Figure PMID:2469701

  7. Study of radiation-induced chromosomal aberrations

    International Nuclear Information System (INIS)

    Wolfring, E.

    2004-06-01

    A method for determining chromosomal aberrations was established for the purpose of examining the relative biological effectiveness (RBE) of photon radiation with respect to mammary epithelium cells. Cells were exposed to 25 kV X-radiation and to 200 kV X-radiation for comparison and the resulting concentrations of chromosomal aberrations were compared. The RBE M value for radiation-induced fragmentation was found to be 4.2 ± 2.4, while the RBE M value for radiation-induced generation of dicentric chromosomes was found to be 0.5 ± 0.5. In addition to the evaluation of chromosomal aberrations the number of cell cycles undergone by the cells was monitored by means of BrDU staining. As expected, the proportion of cells which underwent more than one cell cycle following exposure to 5 Gy was very low in both cases, amounting to 1.9% (25 kV) and 3.2 (200 kV). Non-radiated cells yielded control values of 26.0% and 12.6%, suggesting variations in external conditions from day to day

  8. Effect of coma and spherical aberration on depth-of-focus measured using adaptive optics and computationally blurred images.

    Science.gov (United States)

    Legras, Richard; Benard, Yohann; Lopez-Gil, Norberto

    2012-03-01

    To compare the effect of primary spherical aberration and vertical coma on depth of focus measured with 2 methods. Laboratoire Aimé Cotton, Centre National de la Recherche Scientifique, and Université Paris-Sud, Orsay, France. Evaluation of technology. The subjective depth of focus, defined as the interval of vision for which the target was still perceived acceptable, was evaluated using 2 methods. In the first method, the subject changed the defocus term by reshaping the mirror, which also corrected the subject's aberrations and induced a certain value of coma or primary spherical aberration. In the second procedure, the subject changed the displayed images, which were calculated for various defocuses and with the desired aberration using a numerical eye model. Depth of focus was measured using a 0.18 diopter (D) step in 4 nonpresbyopic subjects corrected for the entire eye aberrations with a 6.0 mm and 3.0 mm pupil and with the addition of 0.3 μm and 0.6 μm of positive primary spherical aberration or vertical coma. There was good concordance between the depth of focus measured with both methods (differences within 1/3 D, r(2) = 0.88). Image-quality metrics failed to predict the subjective depth of focus (r(2) < 0.41). These data confirm that defocus in the retinal image can be generated by optical or computational methods and that both can be used to assess the effect of higher-order aberrations on depth of focus. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  9. Novel low-dose imaging technique for characterizing atomic structures through scanning transmission electron microscope

    Science.gov (United States)

    Su, Chia-Ping; Syu, Wei-Jhe; Hsiao, Chien-Nan; Lai, Ping-Shan; Chen, Chien-Chun

    2017-08-01

    To investigate dislocations or heterostructures across interfaces is now of great interest to condensed matter and materials scientists. With the advances in aberration-corrected electron optics, the scanning transmission electron microscope has demonstrated its excellent capability of characterizing atomic structures within nanomaterials, and well-resolved atomic-resolution images can be obtained through long-exposure data acquisition. However, the sample drifting, carbon contamination, and radiation damage hinder further analysis, such as deriving three-dimensional (3D) structures from a series of images. In this study, a method for obtaining atomic-resolution images with significantly reduced exposure time was developed, using which an original high-resolution image with approximately one tenth the electron dose can be obtained by combining a fast-scan high-magnification image and a slow-scan low-magnification image. The feasibility of obtaining 3D atomic structures using the proposed approach was demonstrated through multislice simulation. Finally, the feasibility and accuracy of image restoration were experimentally verified. This general method cannot only apply to electron microscopy but also benefit to image radiation-sensitive materials using various light sources.

  10. Three-Dimensional scanning transmission electron microscopy of biological specimens

    KAUST Repository

    De Jonge, Niels

    2010-01-18

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM). The specimen was a metallic replica of the biological structure comprising Pt nanoparticles 2-3 nm in diameter, with a high stability under electron beam radiation. The 3D dataset was processed by an automated deconvolution procedure. The lateral resolution was 1.1 nm, set by pixel size. Particles differing by only 10 nm in vertical position were identified as separate objects with greater than 20% dip in contrast between them. We refer to this value as the axial resolution of the deconvolution or reconstruction, the ability to recognize two objects, which were unresolved in the original dataset. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved dataset. © 2010 Microscopy Society of America.

  11. Chromosome painting in biological dosimetry: Semi-automatic system to score stable chromosome aberrations

    International Nuclear Information System (INIS)

    Garcia-Sagredo, J.M.; Vallcorba, I.; Sanchez-Hombre, M.C.; Ferro, M.T.; San Roman Cos-Gayon, C.; Santos, A.; Malpica, N.; Ortiz, C.

    1997-01-01

    From the beginning of the description of the procedure of chromosome painting by fluorescence in situ hybridization (FISH), it was thought its possible application to score induced chromosomal aberrations in radiation exposition. With chromosome painting it is possible to detect changes between chromosomes that has been validated in radiation exposition. Translocation scoring by FISH, contrarily to the unstable dicentrics, mainly detect stable chromosome aberrations that do not disappear, it allows the capability of quantify delayed acute expositions or chronic cumulative expositions. The large number of cells that have to be analyzed for high accuracy, specially when dealing with low radiation doses, makes it almost imperative to use an automatic analysis system. After validate translocation scoring by FISH in our, we have evaluated the ability and sensitivity to detect chromosomal aberrations by chromosome using different paint probes used, showing that any combination of paint probes can be used to score induced chromosomal aberrations. Our group has developed a FISH analysis that is currently being adapted for translocation scoring analysis. It includes systematic error correction and internal control probes. The performance tests carried out show that 9,000 cells can be analyzed in 10 hr. using a Sparc 4/370. Although with a faster computer, a higher throughput is expected, for large population screening or very low radiation doses, this performance still has to be improved. (author)

  12. Fluorescent scanning laser ophthalmoscopy for cellular resolution in vivo mouse retinal imaging: benefits and drawbacks of implementing adaptive optics (Conference Presentation)

    Science.gov (United States)

    Zhang, Pengfei; Goswami, Mayank; Pugh, Edward N.; Zawadzki, Robert J.

    2016-03-01

    Scanning Laser Ophthalmoscopy (SLO) is a very important imaging tool in ophthalmology research. By combing with Adaptive Optics (AO) technique, AO-SLO can correct for ocular aberrations resulting in cellular level resolution, allowing longitudinal studies of single cells morphology in the living eyes. The numerical aperture (NA) sets the optical resolution that can be achieve in the "classical" imaging systems. Mouse eye has more than twice NA of the human eye, thus offering theoretically higher resolution. However, in most SLO based imaging systems the imaging beam size at mouse pupil sets the NA of that instrument, while most of the AO-SLO systems use almost the full NA of the mouse eye. In this report, we first simulated the theoretical resolution that can be achieved in vivo for different imaging beam sizes (different NA), assumingtwo cases: no aberrations and aberrations based on published mouse ocular wavefront data. Then we imaged mouse retinas with our custom build SLO system using different beam sizes to compare these results with theory. Further experiments include comparison of the SLO and AO-SLO systems for imaging different type of fluorescently labeled cells (microglia, ganglion, photoreceptors, etc.). By comparing those results and taking into account systems complexity and ease of use, the benefits and drawbacks of two imaging systems will be discussed.

  13. Correction note.

    Science.gov (United States)

    2014-12-01

    Correction note for Sanders, M., Calam, R., Durand, M., Liversidge, T. and Carmont, S. A. (2008), Does self-directed and web-based support for parents enhance the effects of viewing a reality television series based on the Triple P - Positive Parenting Programme?. Journal of Child Psychology and Psychiatry, 49: 924-932. doi: 10.1111/j.1469-7610.2008.01901.x. © 2014 Association for Child and Adolescent Mental Health.

  14. Head CT scan

    Science.gov (United States)

    ... CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - ... Head CT is done in the hospital or radiology center. You lie on a narrow table that ...

  15. Pelvic CT scan

    Science.gov (United States)

    CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... Abnormal results may be due to: Abscess (collection of pus) Bladder stones Broken bone Cancer Diverticulitis

  16. [Indications for optimized refractive keratoablation. Communication 1. Dependence on the grade of myopia and baseline high-order aberrations].

    Science.gov (United States)

    Avetisov, S E; Karamian, A A; Sukhanova, E V

    2007-01-01

    The authors made a detailed comparative analysis of the aberration pattern of patients before and after aspheric individualized keratoablation (ORK-CAM) and the LASIK operation by routine technology, by taking into account the grade of correctable myopia and the size of baseline high-order aberrations (HOA). Investigations were made in 2 groups: 1) 20 patients (39 eyes) who had undergone routine ablation (a study group); 2) 19 patients (38 eyes) who had aspheric individualized keratoablation (a control group). The findings suggest that individualized aspheric keratoablation is effective in patients with mild and moderate myopia with varying baseline HOA. In addition, a relationship was found between the results of standard and optimized correction and one more key parameter of the aberration pattern, namely the magnitude of 4th-order spherical aberration that should be also taken into account on choosing an eximer laser correction technology. There is an outstanding question whether it is expedient to perform ORK-CAM in patients with high-grade myopia. The above problems require that further studies be continued and will be considered in part 2 of the present investigation.

  17. Closed-loop adaptive optics using a spatial light modulator for sensing and compensating of optical aberrations in ophthalmic applications

    Science.gov (United States)

    Akondi, Vyas; Jewel, Md. Atikur Rahman; Vohnsen, Brian

    2014-09-01

    Sensing and compensating of optical aberrations in closed-loop mode using a single spatial light modulator (SLM) for ophthalmic applications is demonstrated. Notwithstanding the disadvantages of the SLM, in certain cases, this multitasking capability of the device makes it advantageous over existing deformable mirrors (DMs), which are expensive and in general used for aberration compensation alone. A closed-loop adaptive optics (AO) system based on a single SLM was built. Beam resizing optics were used to utilize the large active area of the device and hence make it feasible to generate 137 active subapertures for wavefront sensing. While correcting Zernike aberrations up to fourth order introduced with the help of a DM (for testing purposes), diffraction-limited resolution was achieved. It is shown that matched filter and intensity-weighted centroiding techniques stand out among others. Closed-loop wavefront correction of aberrations in backscattered light from the eyes of three healthy human subjects was demonstrated after satisfactory results were obtained using an artificial eye, which was simulated with a short focal length lens and a sheet of white paper as diffuser. It is shown that the closed-loop AO system based on a single SLM is capable of diffraction-limited correction for ophthalmic applications.

  18. Direct Visualization of Local Electromagnetic Field Structures by Scanning Transmission Electron Microscopy.

    Science.gov (United States)

    Shibata, Naoya; Findlay, Scott D; Matsumoto, Takao; Kohno, Yuji; Seki, Takehito; Sánchez-Santolino, Gabriel; Ikuhara, Yuichi

    2017-07-18

    The functional properties of materials and devices are critically determined by the electromagnetic field structures formed inside them, especially at nanointerface and surface regions, because such structures are strongly associated with the dynamics of electrons, holes and ions. To understand the fundamental origin of many exotic properties in modern materials and devices, it is essential to directly characterize local electromagnetic field structures at such defect regions, even down to atomic dimensions. In recent years, rapid progress in the development of high-speed area detectors for aberration-corrected scanning transmission electron microscopy (STEM) with sub-angstrom spatial resolution has opened new possibilities to directly image such electromagnetic field structures at very high-resolution. In this Account, we give an overview of our recent development of differential phase contrast (DPC) microscopy for aberration-corrected STEM and its application to many materials problems. In recent years, we have developed segmented-type STEM detectors which divide the detector plane into 16 segments and enable simultaneous imaging of 16 STEM images which are sensitive to the positions and angles of transmitted/scattered electrons on the detector plane. These detectors also have atomic-resolution imaging capability. Using these segmented-type STEM detectors, we show DPC STEM imaging to be a very powerful tool for directly imaging local electromagnetic field structures in materials and devices in real space. For example, DPC STEM can clearly visualize the local electric field variation due to the abrupt potential change across a p-n junction in a GaAs semiconductor, which cannot be observed by normal in-focus bright-field or annular type dark-field STEM imaging modes. DPC STEM is also very effective for imaging magnetic field structures in magnetic materials, such as magnetic domains and skyrmions. Moreover, real-time imaging of electromagnetic field structures can

  19. Ultra-fast 3D scanning and holographic illumination in non-linear microscopy using acousto-optic deflectors

    Science.gov (United States)

    Akemann, Walther; Ventalon, Cathie; Léger, Jean-François; Mathieu, Benjamin; Dieudonné, Stéphane; Blochet, Baptiste; Gigan, Sylvain; Bourdieu, Laurent

    2017-04-01

    Decoding of information in the brain requires the imaging of large neuronal networks using e.g. two-photon microscopy (TPM). Fast control of the focus in 3D can be achieved with phase shaping of the light beam using acoustooptic deflectors (AODs). However, beam shaping using AODs is not straightforward because of non-stationary of acousto-optic diffraction. Here, we demonstrated a new stable AOD-based phase modulator, which operates at a rate of up to about hundred kHz. It provides opportunity for 3D scanning in TPM with the possibility to correct aberrations independently for every focus position or to achieve refocusing of scattered photons in rapidly decorrelating tissues.

  20. Chromatically Corrected Imaging Systems for Charged-Particle Radiography

    CERN Document Server

    Blind, Barbara

    2005-01-01

    In proton radiography, imaging with systems consisting of quadrupole magnets is an established technique for viewing the material distribution and composition of objects, either statically or during fast events such as explosions. With the most favorable magnet configuration, the -I lens, chromatic aberrations generally dominate the image blur. Image resolution can be improved, and largely decoupled from the input-beam parameters, by using a second-order achromatic bend with some additional higher-order aberration correction. The aberration-correction approach is discussed. For a given resolution, such a bend allows use of much lower-energy imaging particles than a -I lens. Each bend design represents a set of equivalent systems; an 800-MeV proton design and its equivalent 40-MeV electron system are presented. The electron system is useful for imaging small objects. Magnet errors in the achromatic bends must be tightly controlled to preserve image quality, but not beyond feasibility of present technology. Sys...

  1. Assessment of refractive astigmatism and simulated therapeutic refractive surgery strategies in coma-like-aberrations-dominant corneal optics.

    Science.gov (United States)

    Zhou, Wen; Stojanovic, Aleksandar; Utheim, Tor Paaske

    2016-01-01

    The aim of the study is to raise the awareness of the influence of coma-like higher-order aberrations (HOAs) on power and orientation of refractive astigmatism (RA) and to explore how to account for that influence in the planning of topography-guided refractive surgery in eyes with coma-like-aberrations-dominant corneal optics. Eleven eyes with coma-like-aberrations-dominant corneal optics and with low lenticular astigmatism (LA) were selected for astigmatism analysis and for treatment simulations with topography-guided custom ablation. Vector analysis was used to evaluate the contribution of coma-like corneal HOAs to RA. Two different strategies were used for simulated treatments aiming to regularize irregular corneal optics: With both strategies correction of anterior corneal surface irregularities (corneal HOAs) were intended. Correction of total corneal astigmatism (TCA) and RA was intended as well with strategies 1 and 2, respectively. Axis of discrepant astigmatism (RA minus TCA minus LA) correlated strongly with axis of coma. Vertical coma influenced RA by canceling the effect of the with-the-rule astigmatism and increasing the effect of the against-the-rule astigmatism. After simulated correction of anterior corneal HOAs along with TCA and RA (strategies 1 and 2), only a small amount of anterior corneal astigmatism (ACA) and no TCA remained after strategy 1, while considerable amount of ACA and TCA remained after strategy 2. Coma-like corneal aberrations seem to contribute a considerable astigmatic component to RA in eyes with coma-like-aberrations dominant corneal optics. If topography-guided ablation is programmed to correct the corneal HOAs and RA, the astigmatic component caused by the coma-like corneal HOAs will be treated twice and will result in induced astigmatism. Disregarding RA and treating TCA along with the corneal HOAs is recommended instead.

  2. Demonstrating optical aberrations in the laboratory

    CSIR Research Space (South Africa)

    Naidoo, Darryl

    2009-07-01

    Full Text Available in the laboratory D. Naidoo1,2 , C. Mafusire1,2 and A. Forbes1,2 1 CSIR National Laser Centre 2 School of Physics, University of KwaZulu-Natal AN OPTICAL ABERRATION IS A DISTORTION OF AN IMAGE AS COMPARED TO THE OBJECT DUE TO DEFECTS IN AN OPTICAL SYSTEM TILT...Ne LASER COLLIMATING TELESCOPE MAGNIFICATION 8 TEST LENS SHACK-HARTMANN WAVEFRONT SENSOR FOCAL LENGTH Focal length from Defocus 750 850 950 1050 M e a s u r e d F o c a l L e n g t h ( m m ) Theoretical Experimental...

  3. Effective wavefront aberration measurement of spectacle lenses in as-worn status

    Science.gov (United States)

    Jia, Zhigang; Xu, Kai; Fang, Fengzhou

    2018-04-01

    An effective wavefront aberration analysis method for measuring spectacle lenses in as-worn status was proposed and verified using an experimental apparatus based on an eye rotation model. Two strategies were employed to improve the accuracy of measurement of the effective wavefront aberrations on the corneal sphere. The influences of three as-worn parameters, the vertex distance, pantoscopic angle, and face form angle, together with the eye rotation and corresponding incident beams, were objectively and quantitatively obtained. The experimental measurements of spherical single vision and freeform progressive addition lenses demonstrate the accuracy and validity of the proposed method and experimental apparatus, which provide a potential means of achieving supernormal vision correction with customization and personalization in optimizing the as-worn status-based design of spectacle lenses and evaluating their manufacturing and imaging qualities.

  4. Scanning radiographic apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Albert, R.D.

    1980-04-01

    Visual display of dental, medical or other radiographic images is realized with an x-ray tube in which an electron beam is scanned through an x-y raster pattern on a broad anode plate, the scanning being synchronized with the x-y sweep signals of a cathode ray tube display and the intensity signal for the display being derived from a small x-ray detector which receives x-rays that have passed through the subject to be imaged. Positioning and support of the detector are provided for by disposing the detector in a probe which may be attached to the x-ray tube at any of a plurality of different locations and by providing a plurality of such probes of different configuration in order to change focal length, to accommodate to different detector placements relative to the subject, to enhance patient comfort and to enable production of both periapical images and wider angle pantomographic images. High image definition with reduced radiation dosage is provided for by a lead glass collimator situated between the x-ray tube and subject and having a large number of spaced-apart minute radiation transmissive passages convergent on the position of the detector. Releasable mounting means enable changes of collimator in conjunction with changes of the probe to change focal length. A control circuit modifies the x-y sweep signals applied to the x-ray tube and modulates electron beam energy and current in order to correct for image distortions and other undesirable effects which can otherwise be present in a scanning x-ray system.

  5. Generalized Doppler and aberration kernel for frequency-dependent cosmological observables

    Science.gov (United States)

    Yasini, Siavash; Pierpaoli, Elena

    2017-11-01

    We introduce a frequency-dependent Doppler and aberration transformation kernel for the harmonic multipoles of a general cosmological observable with spin weight s , Doppler weight d and arbitrary frequency spectrum. In the context of cosmic microwave background (CMB) studies, the frequency-dependent formalism allows to correct for the motion-induced aberration and Doppler effects on individual frequency maps with different masks. It also permits to deboost background radiations with non-blackbody frequency spectra, like extragalactic foregrounds and CMB spectra with primordial spectral distortions. The formalism can also be used to correct individual E and B polarization modes and account for motion-induced E/B mixing of polarized observables with d ≠1 at different frequencies. We apply the generalized aberration kernel on polarized and unpolarized specific intensity at 100 and 217 GHz and show that the motion-induced effects typically increase with the frequency of observation. In all-sky CMB experiments, the frequency-dependence of the motion-induced effects for a blackbody spectrum are overall negligible. However in a cut-sky analysis, ignoring the frequency dependence can lead to percent level error in the polarized and unpolarized power spectra over all angular scales. In the specific cut-sky used in our analysis (b >4 5 ° ,fsky≃14 % ), and for the dipole-inferred velocity β =0.00123 typically attributed to our peculiar motion, the Doppler and aberration effects can change polarized and unpolarized power spectra of specific intensity in the CMB rest frame by 1 - 2 % , but we find the polarization cross-leakage between E and B modes to be negligible.

  6. Aberrant Myokine Signaling in Congenital Myotonic Dystrophy

    Directory of Open Access Journals (Sweden)

    Masayuki Nakamori

    2017-10-01

    Full Text Available Summary: Myotonic dystrophy types 1 (DM1 and 2 (DM2 are dominantly inherited neuromuscular disorders caused by a toxic gain of function of expanded CUG and CCUG repeats, respectively. Although both disorders are clinically similar, congenital myotonic dystrophy (CDM, a severe DM form, is found only in DM1. CDM is also characterized by muscle fiber immaturity not observed in adult DM, suggesting specific pathological mechanisms. Here, we revealed upregulation of the interleukin-6 (IL-6 myokine signaling pathway in CDM muscles. We also found a correlation between muscle immaturity and not only IL-6 expression but also expanded CTG repeat length and CpG methylation status upstream of the repeats. Aberrant CpG methylation was associated with transcriptional dysregulation at the repeat locus, increasing the toxic RNA burden that upregulates IL-6. Because the IL-6 pathway is involved in myocyte maturation and muscle atrophy, our results indicate that enhanced RNA toxicity contributes to severe CDM phenotypes through aberrant IL-6 signaling. : Congenital myotonic dystrophy (CDM manifests characteristic genetic (very large CTG repeat expansions, epigenetic (CpG hypermethylation upstream of the repeat, and phenotypic (muscle immaturity features not seen in adult DM. Nakamori et al. find phenotype-genotype and epigenotype correlation in CDM muscle and reveal involvement of the IL-6 myokine signaling pathway in the disease process. Keywords: CTCF, ER stress, IL-6, muscular dystrophy, NF-κB, trinucleotide, cytokine, splicing

  7. Comparison of postoperative higher-order aberrations and contrast sensitivity: tissue-saving versus conventional photorefractive keratectomy for low to moderate myopia.

    Science.gov (United States)

    Hashemi, Hassan; Nazari, Rahman; Amoozadeh, Javad; Beheshtnejad, Amir Houshang; Jabbarvand, Mahmoud; Mohammadpour, Mehrdad; Hashemian, Hesam

    2010-10-01

    To assess the efficacy, predictability, safety, contrast sensitivity, higher-order aberrations (HOAs), and patient satisfaction after tissue-saving photorefractive keratectomy (PRK) and conventional PRK. Department of Ophthalmology, Farabi Eye Hospital, Tehran Medical University, Tehran, Iran. Comparative case series. This prospective study evaluated eyes with low to moderate myopia that had PRK with a Technolas 217z excimer laser. Patients were randomly assigned to have surgery using a conventional algorithm (PlanoScan) or a tissue-saving algorithm (Zyoptix). Contrast sensitivity, HOAs, and patient satisfaction were analyzed preoperatively and 1, 3, and 6 months postoperatively. The conventional group comprised 42 eyes (21 patients) and the tissue-saving group, 62 eyes (31 patients). At 6 months, all eyes in both groups were within ±0.50 diopter of the attempted correction and had an uncorrected distance visual acuity of 20/25 or better. However, the tissue-saving group had a statistically significantly greater increase in the mean root mean square of total HOAs and more induced spherical aberration than the conventional group (P<.05). There was no significant difference between the 2 groups in mesopic or photopic contrast sensitivity. The level of satisfaction after surgery was the same in the 2 groups. Although the conventional and tissue-saving algorithms for PRK were both safe and effective in treating low to moderate myopia, tissue-saving PRK induced a greater increase in HOAs than conventional PRK; this may be because of the smaller blend zone of the tissue-saving algorithm. Contrast sensitivity and patient satisfaction were comparable between the 2 methods. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  8. Higher order aberrations of the eye: Part one

    Directory of Open Access Journals (Sweden)

    Marsha Oberholzer

    2016-03-01

    Full Text Available This article is the first in a series of two articles that provide a comprehensive literature review of higher order aberrations (HOAs of the eye. The present article mainly explains the general principles of such HOAs as well as HOAs of importance, and the measuring apparatus used to measure HOAs of the eye. The second article in the series discusses factors contributing to variable results in measurements of HOAs of the eye.Keywords: Higher order aberrations; wavefront aberrations; aberrometer

  9. Higher order monochromatic aberrations of the human infant eye

    OpenAIRE

    Wang, Jingyun; Candy, T. Rowan

    2005-01-01

    The monochromatic optical aberrations of the eye degrade retinal image quality. Any significant aberrations during postnatal development could contribute to infants’ immature visual performance and provide signals for the control of eye growth. Aberrations of human infant eyes from 5 to 7 weeks old were compared with those of adult subjects using a model of an adultlike infant eye that accounted for differences in both eye and pupil size. Data were collected using the COAS Shack-Hartmann wave...

  10. Higher order aberrations of the eye: Part one

    Directory of Open Access Journals (Sweden)

    Marsha Oberholzer

    2016-06-01

    Full Text Available This article is the first in a series of two articles that provide a comprehensive literature review of higher order aberrations (HOAs of the eye. The present article mainly explains the general principles of such HOAs as well as HOAs of importance, and the measuring apparatus used to measure HOAs of the eye. The second article in the series discusses factors contributing to variable results in measurements of HOAs of the eye. Keywords: Higher order aberrations; wavefront aberrations; aberrometer

  11. FCC-ee final focus with chromaticity correction

    CERN Document Server

    Garcia, H; Tomás, R

    2014-01-01

    A 100 km circular electron-positron collider is considered as one of the possible future high energy facilities. In order to achieve a high luminosity, strong beam focusing at the Interaction Point (IP) is used requiring the correction of the chromatic aberrations. In this paper we study preliminary designs of a Final Focus System (FFS) for the FCC-ee collider with chromatic correction. Beam orbit stability and dynamic aperture calculations are also presented.

  12. Chromosome aberration analysis for biological dosimetry: a review

    International Nuclear Information System (INIS)

    Paul, S.F.D.; Venkatachalam, P.; Jeevanram, R.K.

    1996-01-01

    Among various biological dosimetry techniques, dicentric chromosome aberration method appears to be the method of choice in analysing accidental radiation exposure in most of the laboratories. The major advantage of this method is its sensitivity as the number of dicentric chromosomes present in control population is too small and more importantly radiation induces mainly dicentric chromosome aberration among unstable aberration. This report brings out the historical development of various cytogenetic methods, the basic structure of DNA, chromosomes and different forms of chromosome aberrations. It also highlights the construction of dose-response curve for dicentric chromosome and its use in the estimation of radiation dose. (author)

  13. Chromosome aberrations: plants to human and Feulgen to FISH

    International Nuclear Information System (INIS)

    Natarajan, A.T.

    2005-01-01

    Chromosome aberrations and their impact on human health have been recognized for a long time. In the 1950s, in India, studies on induced chromosome aberrations in plants were initiated by Swaminathan and his students. I trace here the impact of these initial studies on further developments in this field. The studies which were started in plants have been extended to mammals (including human) and the simple squash and solid staining have been improved by molecular cytogenetic techniques, thus enabling accurate identification and quantification of different types of chromosome aberrations. These studies have also thrown light on the mechanisms of chromosome aberration formation, especially following exposure to ionizing radiation. (author)

  14. Orthogonal polynomials describing polarization aberration for rotationally symmetric optical systems.

    Science.gov (United States)

    Xu, Xiangru; Huang, Wei; Xu, Mingfei

    2015-10-19

    Optical lithography has approached a regime of high numerical aperture and wide field, where the impact of polarization aberration on imaging quality turns to be serious. Most of the existing studies focused on the distribution rule of polarization aberration on the pupil, and little attention had been paid to the field. In this paper, a new orthonormal set of polynomials is established to describe the polarization aberration of rotationally symmetric optical systems. The polynomials can simultaneously reveal the distribution rules of polarization aberration on the exit pupil and the field. Two examples are given to verify the polynomials.

  15. Brain PET scan

    Science.gov (United States)

    ... results on a PET scan. Blood sugar or insulin levels may affect the test results in people with diabetes . PET scans may be done along with a CT scan. This combination scan is called a PET/CT. Alternative Names Brain positron emission tomography; PET scan - brain References Chernecky ...

  16. Aberrant Gene Expression in Acute Myeloid Leukaemia

    DEFF Research Database (Denmark)

    Bagger, Frederik Otzen

    genes and genetic signatures and for reducing dimensionally of gene expression data. Next, we have used machine-learning methods to predict survival and to assess important predictors based on these results. General application of a number of these methods has been implemented into two public query......Summary Acute Myeloid Leukaemia (AML) is an aggressive cancer of the bone marrow, affecting formation of blood cells during haematopoiesis. This thesis presents investigation of AML using mRNA gene expression profiles (GEP) of samples extracted from the bone marrow of healthy and diseased subjects....... Here GEPs from purified healthy haematopoietic populations, with different levels of differentiation, form the basis for comparison with diseased samples. We present a mathematical transformation of mRNA microarray data to make it possible to compare AML samples, carrying expanded aberrant...

  17. Surgical treatment for aneurysm at the origin of an aberrant right subclavian artery.

    Science.gov (United States)

    Kokotsakis, John N; Lazopoulos, George L; Lioulias, Achilleas G; Kaskarelis, John S; Romana, Constantina N; Lolas, Christos T

    2003-05-01

    Atherosclerotic aneurysms at the origin of an aberrant right subclavian artery (ARSA) are extremely rare entities of congenital origin. We report a case of a 62-year-old man who presented with dyspnea and upper chest pain. The CT scan and digital subtraction angiography revealed a 7-cm aneurysm of an ARSA arising from Kommerell's diverticulum. Deep hypothermic circulatory arrest was instituted and a transaortic approach was used for closure of the origin of the aneurysm with a prosthetic patch. A Dacron graft was interposed between the right subclavian artery and the ascending aorta and the aneurysmal sac was resected. The patient had an uneventful recovery.

  18. Heart PET scan

    Science.gov (United States)

    ... nuclear medicine scan; Heart positron emission tomography; Myocardial PET scan ... A PET scan requires a small amount of radioactive material (tracer). This tracer is given through a vein (IV), ...

  19. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... of the Thyroid Scan and Uptake? What is a Thyroid Scan and Uptake? A thyroid scan is ... taking our brief survey: Survey Do you have a personal story about radiology? Share your patient story ...

  20. Aberration analysis calculations for synchrotron radiation beamline design

    International Nuclear Information System (INIS)

    McKinney, W.R.; Howells, M.; Padmore, H.A.

    1997-09-01

    The application of ray deviation calculations based on aberration coefficients for a single optical surface for the design of beamline optical systems is reviewed. A systematic development is presented which allows insight into which aberration may be causing the rays to deviate from perfect focus. A new development allowing analytical calculation of line shape is presented

  1. An aberrant uterus: Case report | Ondieki | East African Medical ...

    African Journals Online (AJOL)

    A case of an aberrant uterus is presented and literature reviewed. The patient presented with abnormal uterine bleeding, left iliac fossa pain and was managed by excising the aberrant uterus. This case was an enigma as it didn't present in the classical way one with anomalies of the uterus would present. Despite ...

  2. Aberrant Breast in a Rare Site: A Case Report

    Directory of Open Access Journals (Sweden)

    Levent Yeniay

    2012-01-01

    Full Text Available Aberrant breast tissue is an anomaly in the embryogenesis of the breast that is found along the mammary ridge or out of that line. We report a case of a 71-year-old female patient with an abdominal aberrant breast tissue found incidentally in a piece of mesenteric biopsy. The histological features were consistent with breast tissue.

  3. [An aberrant course of the internal carotid artery].

    Science.gov (United States)

    Hittel, J P; Mertens, J

    2000-09-01

    Aberrant vascular courses of the A. carotis interna are extremely rare. They are usually combined with pulsatile symptoms. Missing symptoms are not proof of a non-existing aberration, though. A paracentesis in such a situation leads to an initially unstoppable bleeding from the tympanion and tuba. For this reason it is necessary to contemplate a vascular reason for the local findings preoperatively.

  4. Expressions for third-order aberration theory for holographic images

    Indian Academy of Sciences (India)

    Expressions for third-order aberration in the reconstructed wave front of point objects are established by Meier. But Smith, Neil Mohon, Sweatt independently reported that their results differ from that of Meier. We found that coefficients for spherical aberration, astigmatism, tally with Meier's while coefficients for distortion and ...

  5. Brown's TRANSPORT up to third order aberration by artificial intelligence

    International Nuclear Information System (INIS)

    Xia Jiawen; Xie Xi; Qiao Qingwen

    1991-01-01

    Brown's TRANSPORT is a first and second order matrix multiplication computer program intended for the design of accelerator beam transport systems, neglecting the third order aberration. Recently a new method was developed to derive analytically any order aberration coefficients of general charged particle optic system, applicable to any practical systems, such as accelerators, electron microscopes, lithographs, etc., including those unknown systems yet to be invented. An artificial intelligence program in Turbo Prolog was implemented on IBM-PC 286 or 386 machine to generate automatically the analytical expression of any order aberration coefficients of general charged particle optic system. Based on this new method and technique, Brown's TRANSPORT is extended beyond the second order aberration effects by artificial intelligence, outputing automatically all the analytical expressions up to the third order aberration coefficients

  6. Chromosome aberration analysis based on a beta-binomial distribution

    International Nuclear Information System (INIS)

    Otake, Masanori; Prentice, R.L.

    1983-10-01

    Analyses carried out here generalized on earlier studies of chromosomal aberrations in the populations of Hiroshima and Nagasaki, by allowing extra-binomial variation in aberrant cell counts corresponding to within-subject correlations in cell aberrations. Strong within-subject correlations were detected with corresponding standard errors for the average number of aberrant cells that were often substantially larger than was previously assumed. The extra-binomial variation is accomodated in the analysis in the present report, as described in the section on dose-response models, by using a beta-binomial (B-B) variance structure. It is emphasized that we have generally satisfactory agreement between the observed and the B-B fitted frequencies by city-dose category. The chromosomal aberration data considered here are not extensive enough to allow a precise discrimination between competing dose-response models. A quadratic gamma ray and linear neutron model, however, most closely fits the chromosome data. (author)

  7. Image based method for aberration measurement of lithographic tools

    Science.gov (United States)

    Xu, Shuang; Tao, Bo; Guo, Yongxing; Li, Gongfa

    2018-01-01

    Information of lens aberration of lithographic tools is important as it directly affects the intensity distribution in the image plane. Zernike polynomials are commonly used for a mathematical description of lens aberrations. Due to the advantage of lower cost and easier implementation of tools, image based measurement techniques have been widely used. Lithographic tools are typically partially coherent systems that can be described by a bilinear model, which entails time consuming calculations and does not lend a simple and intuitive relationship between lens aberrations and the resulted images. Previous methods for retrieving lens aberrations in such partially coherent systems involve through-focus image measurements and time-consuming iterative algorithms. In this work, we propose a method for aberration measurement in lithographic tools, which only requires measuring two images of intensity distribution. Two linear formulations are derived in matrix forms that directly relate the measured images to the unknown Zernike coefficients. Consequently, an efficient non-iterative solution is obtained.

  8. Brown's transport up to third order aberration by artificial intelligence

    International Nuclear Information System (INIS)

    Xia Jiawen; Xie Xi; Qiao Qingwen

    1992-01-01

    Brown's TRANSPORT is a first and second order matrix multiplication computer program intended for the design of accelerator beam transport systems, neglecting the third order aberration. Recently a new method was developed to derive analytically any order aberration coefficients of general charged particle optic system, applicable to any practical systems, such as accelerators, electron microscopes, lithographs, including those unknown systems yet to be invented. An artificial intelligence program in Turbo Prolog was implemented on IBM-PC 286 or 386 machine to generate automatically the analytical expression of any order aberration coefficients of general charged particle optic system. Based on this new method and technique, Brown's TRANSPORT is extended beyond the second order aberration effect by artificial intelligence, outputting automatically all the analytical expressions up to the third order aberration coefficients

  9. Cellular origin of prognostic chromosomal aberrations in AML patients

    DEFF Research Database (Denmark)

    Mora-Jensen, H.; Jendholm, J.; Rapin, N.

    2015-01-01

    of these aberrations occur in normal hematopoietic stem and progenitor cells (HSCs/HPCs) before definitive leukemic transformation through additional acquisition of a few (that is, mostly 1 or 2) leukemia-promoting driver aberrations. NGS studies on sorted bone marrow (BM) populations of AML patients with a normal......Acute myeloid leukemia (AML) represents an aggressive cancer entity, whose malignant cells respond abnormally to regulatory stimuli and have lost the ability to differentiate and become fully mature blood cells.1, 2 AML evolves through accumulation of independent genetic aberrations, including...... karyotype have demonstrated the presence of prognostic driver aberrations (that is, NPM1, FLT3-ITD and FLT3-TKD) in committed HPCs but not in multipotent HSCs. However, the HSC populations lacking the prognostic driver aberrations contained preleukemic clones harboring a series of recurrent molecular...

  10. Adaptive optics binocular visual simulator to study stereopsis in the presence of aberrations.

    Science.gov (United States)

    Fernández, Enrique J; Prieto, Pedro M; Artal, Pablo

    2010-11-01

    A binocular adaptive optics visual simulator has been devised for the study of stereopsis and of binocular vision in general. The apparatus is capable of manipulating the aberrations of each eye separately while subjects perform visual tests. The correcting device is a liquid-crystal-on-silicon spatial light modulator permitting the control of aberrations in the two eyes of the observer simultaneously in open loop. The apparatus can be operated as an electro-optical binocular phoropter with two micro-displays projecting different scenes to each eye. Stereo-acuity tests (three-needle test and random-dot stereograms) have been programmed for exploring the performance of the instrument. As an example, stereo-acuity has been measured in two subjects in the presence of defocus and/or trefoil, showing a complex relationship between the eye's optical quality and stereopsis. This instrument might serve for a better understanding of the relationship of binocular vision and stereopsis performance and the eye's aberrations.

  11. On the benefit of the negative-spherical-aberration imaging technique for quantitative HRTEM

    International Nuclear Information System (INIS)

    Jia, C.L.; Houben, L.; Thust, A.; Barthel, J.

    2010-01-01

    Employing an aberration corrector in a high-resolution transmission electron microscope, the spherical aberration C S can be tuned to negative values, resulting in a novel imaging technique, which is called the negative C S imaging (NCSI) technique. The image contrast obtained with the NCSI technique is compared quantitatively with the image contrast formed with the traditional positive C S imaging (PCSI) technique. For the case of thin objects negative C S images are superior to positive C S images concerning the magnitude of the obtained contrast, which is due to constructive rather than destructive superposition of fundamental contrast contributions. As a consequence, the image signal obtained with a negative spherical aberration is significantly more robust against noise caused by amorphous surface layers, resulting in a measurement precision of atomic positions which is by a factor of 2-3 better at an identical noise level. The quantitative comparison of the two alternative C S -corrected imaging modes shows that the NCSI mode yields significantly more precise results in quantitative high-resolution transmission electron microscopy of thin objects than the traditional PCSI mode.

  12. A resolution insensitive to geometrical aberrations by using incoherent illumination and interference imaging

    Science.gov (United States)

    Xiao, Peng; Fink, Mathias; Gandjbakhche, Amir H.; Claude Boccara, A.

    2017-05-01

    This contribution is another opportunity to acknowledge the influence of Roger Maynard on our research work when he pushed one of us (ACB) to explore the field of waves propagating in complex media rather than limiting ourselves to the wavelength scale of thermal waves or near field phenomena. Optical tomography is used for imaging in-depth scattering media such as biological tissues. Optical coherence tomography (OCT) plays an important role in imaging biological samples. Coupling OCT with adaptive optics (AO) in order to correct eye aberrations has led to cellular imaging of the retina. By using our approach called Full-Field OCT (FFOCT) we show that, with spatially incoherent illumination, the width of the point-spread function (PSF) that governs the resolution is not affected by aberrations that induce only a reduction of the signal level. We will describe our approach by starting with the PSF experimental data followed by a simple theoretical analysis, and numerical calculations. Finally full images obtained through or inside scattering and aberrating media will be shown.

  13. Multiphoton imaging microscopy at deeper layers with adaptive optics control of spherical aberration.

    Science.gov (United States)

    Bueno, Juan M; Skorsetz, Martin; Palacios, Raquel; Gualda, Emilio J; Artal, Pablo

    2014-01-01

    Despite the inherent confocality and optical sectioning capabilities of multiphoton microscopy, three-dimensional (3-D) imaging of thick samples is limited by the specimen-induced aberrations. The combination of immersion objectives and sensorless adaptive optics (AO) techniques has been suggested to overcome this difficulty. However, a complex plane-by-plane correction of aberrations is required, and its performance depends on a set of image-based merit functions. We propose here an alternative approach to increase penetration depth in 3-D multiphoton microscopy imaging. It is based on the manipulation of the spherical aberration (SA) of the incident beam with an AO device while performing fast tomographic multiphoton imaging. When inducing SA, the image quality at best focus is reduced; however, better quality images are obtained from deeper planes within the sample. This is a compromise that enables registration of improved 3-D multiphoton images using nonimmersion objectives. Examples on ocular tissues and nonbiological samples providing different types of nonlinear signal are presented. The implementation of this technique in a future clinical instrument might provide a better visualization of corneal structures in living eyes.

  14. Non-invasive transcranial ultrasound therapy based on a 3D CT scan: protocol validation and in vitro results

    Energy Technology Data Exchange (ETDEWEB)

    Marquet, F; Pernot, M; Aubry, J-F; Montaldo, G; Tanter, M; Fink, M [Laboratoire Ondes et Acoustique, ESPCI, Universite Paris VII, UMR CNRS 7587, 10 rue Vauquelin, 75005 Paris (France); Marsac, L [Supersonic Imagine, Les Jardins de la Duranne, 510 rue Rene Descartes, 13857 Aix-en-Provence (France)], E-mail: fabrice.marquet@espci.org

    2009-05-07

    A non-invasive protocol for transcranial brain tissue ablation with ultrasound is studied and validated in vitro. The skull induces strong aberrations both in phase and in amplitude, resulting in a severe degradation of the beam shape. Adaptive corrections of the distortions induced by the skull bone are performed using a previous 3D computational tomography scan acquisition (CT) of the skull bone structure. These CT scan data are used as entry parameters in a FDTD (finite differences time domain) simulation of the full wave propagation equation. A numerical computation is used to deduce the impulse response relating the targeted location and the ultrasound therapeutic array, thus providing a virtual time-reversal mirror. This impulse response is then time-reversed and transmitted experimentally by a therapeutic array positioned exactly in the same referential frame as the one used during CT scan acquisitions. In vitro experiments are conducted on monkey and human skull specimens using an array of 300 transmit elements working at a central frequency of 1 MHz. These experiments show a precise refocusing of the ultrasonic beam at the targeted location with a positioning error lower than 0.7 mm. The complete validation of this transcranial adaptive focusing procedure paves the way to in vivo animal and human transcranial HIFU investigations.

  15. Reducing depth induced spherical aberration in 3D widefield fluorescence microscopy by wavefront coding using the SQUBIC phase mask

    Science.gov (United States)

    Patwary, Nurmohammed; Doblas, Ana; King, Sharon V.; Preza, Chrysanthe

    2014-03-01

    Imaging thick biological samples introduces spherical aberration (SA) due to refractive index (RI) mismatch between specimen and imaging lens immersion medium. SA increases with the increase of either depth or RI mismatch. Therefore, it is difficult to find a static compensator for SA1. Different wavefront coding methods2,3 have been studied to find an optimal way of static wavefront correction to reduce depth-induced SA. Inspired by a recent design of a radially symmetric squared cubic (SQUBIC) phase mask that was tested for scanning confocal microscopy1 we have modified the pupil using the SQUBIC mask to engineer the point spread function (PSF) of a wide field fluorescence microscope. In this study, simulated images of a thick test object were generated using a wavefront encoded engineered PSF (WFEPSF) and were restored using space-invariant (SI) and depth-variant (DV) expectation maximization (EM) algorithms implemented in the COSMOS software4. Quantitative comparisons between restorations obtained with both the conventional and WFE PSFs are presented. Simulations show that, in the presence of SA, the use of the SIEM algorithm and a single SQUBIC encoded WFE-PSF can yield adequate image restoration. In addition, in the presence of a large amount of SA, it is possible to get adequate results using the DVEM with fewer DV-PSFs than would typically be required for processing images acquired with a clear circular aperture (CCA) PSF. This result implies that modification of a widefield system with the SQUBIC mask renders the system less sensitive to depth-induced SA and suitable for imaging samples at larger optical depths.

  16. Adult hippocampal neurogenesis poststroke: More new granule cells but aberrant morphology and impaired spatial memory.

    Science.gov (United States)

    Woitke, Florus; Ceanga, Mihai; Rudolph, Max; Niv, Fanny; Witte, Otto W; Redecker, Christoph; Kunze, Albrecht; Keiner, Silke

    2017-01-01

    Stroke significantly stimulates neurogenesis in the adult dentate gyrus, though the functional role of this postlesional response is mostly unclear. Recent findings suggest that newborn neurons generated in the context of stroke may fail to correctly integrate into pre-existing networks. We hypothesized that increased neurogenesis in the dentate gyrus following stroke is associated with aberrant neurogenesis and impairment of hippocampus-dependent memory. To address these questions we used the middle cerebral artery occlusion model (MCAO) in mice. Animals were housed either under standard conditions or with free access to running wheels. Newborn granule cells were labelled with the thymidine analoque EdU and retroviral vectors. To assess memory performance, we employed a modified version of the Morris water maze (MWM) allowing differentiation between hippocampus dependent and independent learning strategies. Newborn neurons were morphologically analyzed using confocal microscopy and Neurolucida system at 7 weeks. We found that neurogenesis was significantly increased following MCAO. Animals with MCAO needed more time to localize the platform and employed less hippocampus-dependent search strategies in MWM versus controls. Confocal studies revealed an aberrant cell morphology with basal dendrites and an ectopic location (e.g. hilus) of new granule cells born in the ischemic brain. Running increased the number of new neurons but also enhanced aberrant neurogenesis. Running, did not improve the general performance in the MWM but slightly promoted the application of precise spatial search strategies. In conclusion, ischemic insults cause hippocampal-dependent memory deficits which are associated with aberrant neurogenesis in the dentate gyrus indicating ischemia-induced maladaptive plasticity in the hippocampus.

  17. Higher-Order Wavefront Aberrations for Populations of Young Emmetropes and Myopes

    Directory of Open Access Journals (Sweden)

    Jinhua Bao

    2009-01-01

    Conclusions: Human eyes have systematical higher order aberrations in population, and factors that cause bilateral symmetry of wavefront aberrations between the right and left eyes made important contribution to the systematical aberrations.

  18. Structural characterization of Pt–Pd core–shell nanoparticles by Cs-corrected STEM

    International Nuclear Information System (INIS)

    Esparza, R.; García-Ruiz, Amado F.; Velázquez Salazar, J. J.; Pérez, R.; José-Yacamán, M.

    2013-01-01

    Pt–Pd core–shell nanoparticles were synthesized using a modified polyol method. A thermal method under refluxing, carrying on the reaction up to 285 °C, has been performed to reduce metallic salts using ethylene glycol as reducer and poly(N-vinyl-2-pyrrolidone) as protective reagent of the formed bimetallic nanoparticles. According to other works, this type of structure has been studied and utilized to successfully increase the catalytic properties of monometallic nanoparticles Pt or Pd. Core–shell bimetallic nanoparticles were structurally characterized using aberration-corrected scanning transmission electron microscopy (Cs-STEM) equipped with a high-angle annular dark field detector, energy-dispersive X-ray spectrometry (EDS), and electron energy-loss spectroscopy (EELS). The high-resolution elemental line scan and mappings were carried out using a combination of STEM–EDS and STEM–EELS. The obtained results show the growth of the Pd shell on the Pt core with polyhedral morphology. The average size of the bimetallic nanoparticles was 13.5 nm and the average size of the core was 8.5 nm; consequently, the thickness of the shell was around 2.5 nm. The growth of the Pd shell on the Pt core is layer by layer, suggesting a Frank-van der Merwe growth mechanism.

  19. Structural characterization of Pt-Pd core-shell nanoparticles by Cs-corrected STEM

    Energy Technology Data Exchange (ETDEWEB)

    Esparza, R., E-mail: resparza@fata.unam.mx [Universidad Nacional Autonoma de Mexico, Centro de Fisica Aplicada y Tecnologia Avanzada (Mexico); Garcia-Ruiz, Amado F. [UPIICSA-COFAA, Instituto Politecnico Nacional (Mexico); Velazquez Salazar, J. J. [University of Texas at San Antonio, Department of Physics and Astronomy (United States); Perez, R. [Universidad Nacional Autonoma de Mexico, Centro de Fisica Aplicada y Tecnologia Avanzada (Mexico); Jose-Yacaman, M. [The University of Texas at San Antonio, Department of Physics and Astronomy (United States)

    2013-01-15

    Pt-Pd core-shell nanoparticles were synthesized using a modified polyol method. A thermal method under refluxing, carrying on the reaction up to 285 Degree-Sign C, has been performed to reduce metallic salts using ethylene glycol as reducer and poly(N-vinyl-2-pyrrolidone) as protective reagent of the formed bimetallic nanoparticles. According to other works, this type of structure has been studied and utilized to successfully increase the catalytic properties of monometallic nanoparticles Pt or Pd. Core-shell bimetallic nanoparticles were structurally characterized using aberration-corrected scanning transmission electron microscopy (Cs-STEM) equipped with a high-angle annular dark field detector, energy-dispersive X-ray spectrometry (EDS), and electron energy-loss spectroscopy (EELS). The high-resolution elemental line scan and mappings were carried out using a combination of STEM-EDS and STEM-EELS. The obtained results show the growth of the Pd shell on the Pt core with polyhedral morphology. The average size of the bimetallic nanoparticles was 13.5 nm and the average size of the core was 8.5 nm; consequently, the thickness of the shell was around 2.5 nm. The growth of the Pd shell on the Pt core is layer by layer, suggesting a Frank-van der Merwe growth mechanism.

  20. Third order aberration theory of double Wien filters

    Science.gov (United States)

    Ioanoviciu, D.; Tsuno, K.; Martinez, G.

    2004-11-01

    The second and the third order aberration theory for a double Wien filter have been analytically developed. A new second order aberration-free condition is found at the image plane of the second filter. This condition is met when b2=-1/4, e2=-1/2, and b3-e3=-1/8, where b2=B2R/B1, e2=E2R/E1, b3=B3R2/B1, and e3=E3R2/E1. Here, R is the cyclotron radius and E1, B1, E2, B2, E3, and B3 are the dipole, quadrupole, and hexapole components of electric and magnetic fields, respectively. This condition is different from the second order aberration-free condition for a single Wien filter, which is satisfied when b2=-3/4, e2=-1, and b3-e3=-3/8. The geometrical second order aberration-free condition has also been found, and requires that e3-b3=(m-1)/8, e2=-m/4, and b2=(1-m)/4. This last set is sufficient to satisfy the above two sets of conditions as well. Residual third order aberrations are calculated for various m. The third order aberrations at the second focus are very small when the new aberration-free condition is fulfilled.

  1. Chromosome aberrations in solid tumors have a stochastic nature

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Mauro A.A. [Departamento de Bioquimica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-anexo, Porto Alegre 90035-003 (Brazil) and Departamento de Medicina Interna, Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2350, Porto Alegre 90035-903 (Brazil) and Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Porto Alegre 91501-970 (Brazil) and Universidade Luterana do Brasil, Rua Miguel Tostes 101, Canoas 92420-280 (Brazil)]. E-mail: mauro@ufrgs.br; Onsten, Tor G.H. [Departamento de Medicina Interna, Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2350, Porto Alegre 90035-903 (Brazil); Universidade Luterana do Brasil, Rua Miguel Tostes 101, Canoas 92420-280 (Brazil); Moreira, Jose C.F. [Departamento de Bioquimica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-anexo, Porto Alegre 90035-003 (Brazil); Almeida, Rita M.C. de [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Porto Alegre 91501-970 (Brazil)

    2006-08-30

    An important question nowadays is whether chromosome aberrations are random events or arise from an internal deterministic mechanism, which leads to the delicate task of quantifying the degree of randomness. For this purpose, we have defined several Shannon information functions to evaluate disorder inside a tumor and between tumors of the same kind. We have considered 79 different kinds of solid tumors with 30 or more karyotypes retrieved from the Mitelman Database of Chromosome Aberrations in Cancer. The Kaplan-Meier cumulative survival was also obtained for each solid tumor type in order to correlate data with tumor malignance. The results here show that aberration spread is specific for each tumor type, with high degree of diversity for those tumor types with worst survival indices. Those tumor types with preferential variants (e.g. high proportion of a given karyotype) have shown better survival statistics, indicating that aberration recurrence is a good prognosis. Indeed, global spread of both numerical and structural abnormalities demonstrates the stochastic nature of chromosome aberrations by setting a signature of randomness associated to the production of disorder. These results also indicate that tumor malignancy correlates not only with karyotypic diversity taken from different tumor types but also taken from single tumors. Therefore, by quantifying aberration spread, we could confront diverse models and verify which of them points to the most likely outcome. Our results suggest that the generating process of chromosome aberrations is neither deterministic nor totally random, but produces variations that are distributed between these two boundaries.

  2. Aberrant intestinal microbiota in individuals with prediabetes

    DEFF Research Database (Denmark)

    Allin, Kristine H.; Tremaroli, Valentina; Caesar, Robert

    2018-01-01

    with prediabetes and those with normal glucose regulation. At the genus level, the abundance of Clostridium was decreased (mean log2 fold change −0.64 (SEM 0.23), padj = 0.0497), whereas the abundances of Dorea, [Ruminococcus], Sutterella and Streptococcus were increased (mean log2 fold change 0.51 (SEM 0...... individuals with prediabetes (mean log2 fold change −1.74 (SEM 0.41), padj = 2 × 10−3 and −1.65 (SEM 0.34), padj = 4 × 10−4, respectively). Faecal transfer from donors with prediabetes or screen-detected, drug-naive type 2 diabetes to germfree Swiss Webster or conventional C57BL/6 J mice did not induce...... impaired glucose regulation in recipient mice. Conclusions/interpretation: Collectively, our data show that individuals with prediabetes have aberrant intestinal microbiota characterised by a decreased abundance of the genus Clostridium and the mucin-degrading bacterium A. muciniphila. Our findings...

  3. The Compact Hyperspectral Aberration-corrected Platform (CHAP), an instrument for microspacecraft., Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In-situ analysis of solar system bodies plays a crucial role in understanding the evolution of our planet, setting the stage for life's origins. As has been...

  4. The Compact Hyperspectral Aberration-Corrected Platform (CHAP), an Instrument for Microspacecraft., Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In-situ analysis of solar system bodies plays a crucial role in understanding the evolution of our planet, setting the stage for life's origins. As has been...

  5. Chromatic aberration correction and deconvolution for UV sensitive imaging of fluorescent sterols in cytoplasmic lipid droplets

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Faergeman, Nils J

    2008-01-01

    adipocyte differentiation. DHE is targeted to transferrin-positive recycling endosomes in preadipocytes but associates with droplets in mature adipocytes. Only in adipocytes but not in foam cells fluorescent sterol was confined to the droplet-limiting membrane. We developed an approach to visualize...... macrophage foam cells and in adipocytes. We used deconvolution microscopy and developed image segmentation techniques to assess the DHE content of lipid droplets in both cell types in an automated manner. Pulse-chase studies and colocalization analysis were performed to monitor the redistribution of DHE upon...

  6. Chromosome aberrations analysis of Serbia population from 1985 to 1995

    International Nuclear Information System (INIS)

    Jovicic, D.; Markovic, B.; Milacic, S.; Joksic, G.

    1996-01-01

    After the accident of NE Chernobyl in May 1986, Chernobyl's fallout with unhomogeneous dispersion of radioactive material in atmosphere caused the difference in contamination of the Serbia territory. The highest contamination was found to be in region Uzice, and the lowest in the region Nis. Two groups of population from these regions were undergone chromosome aberration analysis during 1987, 1988 and 1989. year. The results of our examination show increased frequency of structural chromosome aberrations/dicentrics, rings, peri centric inversions and acentric/ in the Uzice population, especially in the 1987. year. In 1985 and 1995 year have not been found chromosome aberrations. 2 refs.; 1 figs.; 2 tabs

  7. Effect of unilateral congenital ptosis on ocular higher order aberrations in children.

    Science.gov (United States)

    Ashok Kumar, Dhivya; Agarwal Ms, Amar; Prakash, Gaurav; Vajpayee Boptm, Neha; Packiyalakshmi, Sathiya; Agarwal, Athiya

    2013-01-01

    To analyse the effect of congenital unilateral ptosis on the ocular higher order aberrations (HOA) and to compare these eyes with normal fellow eyes this study has been performed. In this observational comparative case series, 16 eyes of 16 patients less than 15 years old with congenital unilateral upper eyelid ptosis were included. Corrected distance visual acuity (CDVA), corneal topography, ocular HOA's with Zywave workstation was recorded. The amount of ptosis was measured from marginal reflex distance (MRD1). The ocular HOA's were compared between the ptosis and the normal fellow eyes after making necessary corrections to avoid errors due to enantiomeric midline symmetry. The mean age was 12.5±2.7years (range7-15years). The mean MRD1 was -0.9±1.8mm in the ptosis eyes. There was significant difference noted in the mean 6mm Zernicke coefficients Z3 (-3) (p=0.002), Z4 (-2) (p=0.034), Z4 (2) (p=0.008), Z5 (-5) (p=0.044), Z5 (1) (p=0.039), Z5 (3) (p=0.036), Z5 (5) (p=0.044) between the ptosis and the fellow eyes. The mean Z3-3 was -0.17±0.15 and 0.07±0.12 in the ptosis and the normal eyes respectively. There was a significant difference (p=0.023) in total RMS (root mean square) between the ptosis and the normal eyes. Total coma aberration correlated with CDVA (p=0.004) and MRD (p=0.030) in the ptosis eyes. There was no correlation (p=0.815) between the age (duration of ptosis) and total RMS. In conclusion, Eyes with congenital ptosis differed from their normal fellow eyes in the higher order aberrations. None of the HOA's which differed between the two groups affected the visual acuity in the ptosis eyes.

  8. Aberrations of Genetic Material as Biomarkers of Ionizing Radiation Effects

    Energy Technology Data Exchange (ETDEWEB)

    Milacic, S.

    2004-07-01

    Ionizing radiation is the most powerful mutagen in environmental and working conditions. The result of genotoxic effect of radiation is the development of chromosome aberrations. The structural chromosome aberrations in peripheral blood lymphocytes are dicentric, ring, acentric fragment. The observation of chromosome aberration frequency in lymphocyte karyotype is the conclusive method to assess the absorbed dose of ionizing radiation. Our study compared the incidence of chromosome aberrations in occupationally exposed healthy medical workers and in non-exposed healthy population. We analyzed the effect of working place, dose by thermo luminescence personal dosimeter (TLD), duration of occupational exposure (DOE) and age to the sum of aberrant cells and aberrations. four-year study included 462 subjects, mean-aged 42.3 years, who were occupational exposed to ionizing radiation and 95 subjects, mean-aged 35,2 years, who were not exposed to ionizing radiation, during the same time period and from the same territory. All of them possess thermo luminescence personal dosimeter (TLD) which is read by scanner for thermo luminescence dosimeters. Modified Moorheard's micro method for peripheral blood lymphocytes and conventional cytogenetic technique of chromosome aberration analysis were used for analysis of chromosome aberrations. Stained preparations (Giemsa) are observed in immersion by light microscope. The karyotype of 200 lymphocytes in metaphase is analyzed the most characteristic aberration: dicentric, then the ring and acentric fragments. The increased incidence of chromosome aberrations was found to tbe 21.6% in the exposed group and 2.1% in the controls, while the findings within the limits (non-specific chromosome lesions-gaps breaks, elongations, and exchanges) were equal in both groups (22%). Among occupationally exposed medical workers, the highest incidence was found in nuclear medicine workers (42.6%), then in orthopedists (27.08%). There is highly

  9. Computer-assisted detection of chromosomal aberrations for the purpose of establishing a biological dosimeter

    International Nuclear Information System (INIS)

    Ueberreiter, B.

    1982-01-01

    Using a special high-resolution microscopy apparatus, digital light microscope images of human chromosomes were generated, and specific image processing algorithms were developed. The pattern recognition process for computer-assisted detection of specific, radiation-induced chromosomal aberrations comprises three steps: First, the orientation of the segmented objects is defined and corrected. For date reduction purposes, the individual chromosomes are reduced to a few basic types containing typical information. After a linear transformation step, the characteristic parameters thus derived form a parameter vector for statistical classification. The method was well suited for distinguishing normal chromosomes from chromosomal aberrations. 94% of the objects were identified correctly. To achieve even higher accuracy, quality standards were set by which suspectedly misclassified objects can be re-investigated in dialog by the human observer. Implementation of the program system for parameter extraction on a fast polyprocessor system opens up a realistic chance of reducing the computing time for dose estimates to about one hour. (orig./MG) [de

  10. Chromosome aberration studies and microdosimetry with radiations of varying quality

    International Nuclear Information System (INIS)

    Grillmaier, R.E.; Bihy, L.; Menzel, H.G.; Schuhmacher, H.

    1978-01-01

    To investigate the biological effectivity of complex irradiation fields encountered in radiation protection and high LET radiation therapy and to find meaningful specification of radiation quality closely related to the biological effectivity, correlated chromosome aberration studies and microdosimetric investigations have been carried out using cyclotron produced collimated fast neutrons. Human lymphocytes have been irradiated at different dose levels in the direct beam and in different positions in the penumbra and the rates of acentric fragments and dicentrics have been determined. In identical positions microdosimetric measurements have been performed. The dose relationship of aberration rates after irradiation in the direct beam, the aberration rates observed in the penumbra and the microdosimetric quantities ysub(D), ysub(F) and y* are presented and their relations are discussed. Furthermore the dose relationship of chromosome aberrations induced by 60 Co-γ-rays has been investigated and used to establish the RBE dose relationship of cyclotron neutrons

  11. Aberrant internal carotid artery in the middle ear

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Keun Tak; Kang, Hyun Koo [Dept. of Radiology, Seoul Veterans Hospital, Seoul (Korea, Republic of)

    2014-10-15

    The knowledge about the aberrant internal carotid artery (ICA) in the middle ear is essential for clinicians, because a misdiagnosis of the aberrant ICA could have serious consequences such as excessive aural bleeding during a middle ear surgery. A 38-year-old woman presented with tinnitus and hearing difficulties of the left ear that had started 5 years ago. During otoscopy, an anteroinferior bluish mass was seen in the tympanic space. Computed tomography and magnetic resonance imaging demonstrated a left-side aberrant ICA with bony dehiscence of the carotid canal in the middle ear and a reduced diameter of the tympanic ICA. Herein we report a case of an aberrant ICA in the middle ear. We also review the literature regarding this important vascular anomaly of the temporal bone which may lead to disastrous surgical complications.

  12. Aberrant internal carotid artery in the middle ear

    International Nuclear Information System (INIS)

    Roh, Keun Tak; Kang, Hyun Koo

    2014-01-01

    The knowledge about the aberrant internal carotid artery (ICA) in the middle ear is essential for clinicians, because a misdiagnosis of the aberrant ICA could have serious consequences such as excessive aural bleeding during a middle ear surgery. A 38-year-old woman presented with tinnitus and hearing difficulties of the left ear that had started 5 years ago. During otoscopy, an anteroinferior bluish mass was seen in the tympanic space. Computed tomography and magnetic resonance imaging demonstrated a left-side aberrant ICA with bony dehiscence of the carotid canal in the middle ear and a reduced diameter of the tympanic ICA. Herein we report a case of an aberrant ICA in the middle ear. We also review the literature regarding this important vascular anomaly of the temporal bone which may lead to disastrous surgical complications.

  13. Herpes,zoster with Wrist Drop and Aberrant Lesions

    Directory of Open Access Journals (Sweden)

    R K Dutta

    1987-01-01

    Full Text Available A patient having herpes zoster involving C6, 7, 8, Dl and 2 segments, developed ipsilateral wrist drop and aberrant lesions. Paralytic deformity preceded the skin eruption by one day.

  14. Aberrant Chromatin Modification as a Mechanism of Prostate Cancer Progression

    National Research Council Canada - National Science Library

    Chen, Hongwu

    2004-01-01

    .... However, the underlying mechanism is still unclear. The purpose of this study is to test the hypothesis that aberrant chromatin modification plays a critical role in prostate cancer progression...

  15. Low level dose induced chromosome aberrations in human blood lymphocytes

    International Nuclear Information System (INIS)

    Pohl-Rueling, J.

    1992-01-01

    Unstable structural aberrations in chromosomes of human blood lymphocytes cannot be used as biological dosemeters in the low dose range, when extrapolating from high doses using a linear dose response, as required by the original formula of the dual radiation action theory. A survey is given of experimental dose-response curves of chromosome aberrations, obtained in investigations not only by this institute, in cooperation with many other laboratories, but also by various authors in different areas of the world. The results are not compatible with the predicted linear dose relationships at in vivo dose ranges up to 30 mGy.y -1 . The aberration frequencies rise sharply with dose within the normal environmental exposure up to about twice that level. At higher doses, aberration frequencies increase less rapidly and reach a plateau. Some in vitro experiments of various authors with higher doses of low LET radiations, up to about 400 mGy have found dose responses with steps. (author)

  16. Impact of primary aberrations on coherent lidar performance

    DEFF Research Database (Denmark)

    Hu, Qi; Rodrigo, Peter John; Iversen, Theis Faber Quist

    2014-01-01

    of the lidar system using different optical transceiver configurations. A rotating belt is used as a hard target. Our study shows that the lidar weighting function suffers from both spatial broadening and shift in peak position in the presence of aberration. It is to our knowledge the first experimental......In this work we investigate the performance of a monostatic coherent lidar system in which the transmit beam is under the influence of primary phase aberrations: spherical aberration (SA) and astigmatism. The experimental investigation is realized by probing the spatial weighting function...... effciency, the optimum truncation of the transmit beam and the spatial sensitivity of a CW coherent lidar system. Under strong degree of aberration, the spatial confinement is significantly degraded. However for SA, the degradation of the spatial confinement can be reduced by tuning the truncation...

  17. Establishing working standards of chromosome aberrations analysis for biological dosimetry

    International Nuclear Information System (INIS)

    Bui Thi Kim Luyen; Tran Que; Pham Ngoc Duy; Nguyen Thi Kim Anh; Ha Thi Ngoc Lien

    2015-01-01

    Biological dosimetry is an dose assessment method using specify bio markers of radiation. IAEA (International Atomic Energy Agency) and ISO (International Organization for Standardization) defined that dicentric chromosome is specify for radiation, it is a gold standard for biodosimetry. Along with the documents published by IAEA, WHO, ISO and OECD, our results of study on the chromosome aberrations induced by radiation were organized systematically in nine standards that dealing with chromosome aberration test and micronucleus test in human peripheral blood lymphocytes in vitro. This standard addresses: the reference dose-effect for dose estimation, the minimum detection levels, cell culture, slide preparation, scoring procedure for chromosome aberrations use for biodosimetry, the criteria for converting aberration frequency into absorbed dose, reporting of results. Following these standards, the automatic analysis devices were calibrated for improving biological dosimetry method. This standard will be used to acquire and maintain accreditation of the Biological Dosimetry laboratory in Nuclear Research Institute. (author)

  18. Chromosome aberrations in pesticide-exposed greenhouse workers

    DEFF Research Database (Denmark)

    Lander, B F; Knudsen, Lisbeth E.; Gamborg, M O

    2000-01-01

    OBJECTIVES: The aim of this study was to investigate the possibility of subtoxic exposure to pesticides causing chromosome aberrations in greenhouse workers. METHODS: In a cross-sectional and prospective study design chromosome aberration frequencies in cultured lymphocytes were examined for 116...... greenhouse workers exposed to a complex mixture of almost 50 insecticides, fungicides, and growth regulators and also for 29 nonsmoking, nonpesticide-exposed referents. RESULTS: The preseason frequencies of chromosome aberrations were slightly but not statistically significantly elevated for the greenhouse...... workers when they were compared with the referents. After a summer season of pesticide spraying in the greenhouses, the total frequencies of cells with chromosome aberrations were significantly higher than in the preseason samples (P=0.02) and also higher than for the referents (P=0.05). This finding...

  19. 78 FR 75449 - Miscellaneous Corrections; Corrections

    Science.gov (United States)

    2013-12-12

    ... cross- references, correcting grammatical errors, revising language for clarity and consistency, and... practice. Specifically, these amendments are to correct grammatical errors and to revise cross-references.... The final rule contained minor errors in grammar, punctuation, and referencing. This document corrects...

  20. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan ... for several hours before your exam because eating can affect the accuracy of the uptake measurement. Jewelry ...

  1. Radiopharmaceutical scanning agents

    International Nuclear Information System (INIS)

    1976-01-01

    This invention is directed to dispersions useful in preparing radiopharmaceutical scanning agents, to technetium labelled dispersions, to methods for preparing such dispersions and to their use as scanning agents

  2. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... the limitations of the Thyroid Scan and Uptake? What is a Thyroid Scan and Uptake? A thyroid ... body converts food to energy. top of page What are some common uses of the procedure? The ...

  3. Nuclear Scans - Multiple Languages

    Science.gov (United States)

    ... Expand Section Bone Scan - 简体中文 (Chinese, Simplified (Mandarin dialect)) Bilingual PDF Health Information Translations PET (Positron Emission Tomography) Scan - 简体中文 (Chinese, Simplified ( ...

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Scan and Uptake Thyroid scan and uptake uses small amounts of radioactive materials called radiotracers, a special ... is a branch of medical imaging that uses small amounts of radioactive material to diagnose and determine ...

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... of page What will I experience during and after the procedure? Most thyroid scan and thyroid uptake ... you otherwise, you may resume your normal activities after your nuclear medicine scan. If any special instructions ...

  6. Aberrant cervical thymus mimicking thyroid on ultrasonography: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Sub; Park, Ju Hyun; Kim, Bong Soo; Park, Ji Kang; Choi, Jae Hyuck [Jeju National Univ. Hospital/Jeju National Univ. School of Medicine, Jeju (Korea, Republic of)

    2012-10-15

    Aberrant cervical thymus is rarely reported in adults. We report a case of solid aberrant cervical thymus in a 27 year old female, which was found incidentally on ultrasonography for the evaluation of the thyroid cancer. On ultrasonography, the lesion was found between the left thyroid and common carotid artery without any remarkable interface echo, and had similar echogenicity to the thyroid. The lesion extended to the upper pole of the left thyroid.

  7. Adaptive optics enables 3D STED microscopy in aberrating specimens.

    Science.gov (United States)

    Gould, Travis J; Burke, Daniel; Bewersdorf, Joerg; Booth, Martin J

    2012-09-10

    Stimulated emission depletion (STED) microscopy allows fluorescence far-field imaging with diffraction-unlimited resolution. Unfortunately, extending this technique to three-dimensional (3D) imaging of thick specimens has been inhibited by sample-induced aberrations. Here we present the first implementation of adaptive optics in STED microscopy to allow 3D super-resolution imaging in strongly aberrated imaging conditions, such as those introduced by thick biological tissue.

  8. Adaptive optics enables 3D STED microscopy in aberrating specimens

    Science.gov (United States)

    Gould, Travis J.; Burke, Daniel; Bewersdorf, Joerg; Booth, Martin J.

    2012-01-01

    Stimulated emission depletion (STED) microscopy allows fluorescence far-field imaging with diffraction-unlimited resolution. Unfortunately, extending this technique to three-dimensional (3D) imaging of thick specimens has been inhibited by sample-induced aberrations. Here we present the first implementation of adaptive optics in STED microscopy to allow 3D super-resolution imaging in strongly aberrated imaging conditions, such as those introduced by thick biological tissue. PMID:23037223

  9. Moment aberrations in magneto-electrostatic plasma lenses (computer simulation)

    CERN Document Server

    Butenko, V I

    2001-01-01

    In this work moment aberrations in the plasma magneto-electrostatic lenses are considered in more detail with the use of the computer modeling. For solution of the problem we have developed a special computer code - the model of plasma optical focusing device, allowing to display the main parameters and operations of experimental sample of a lens, to simulate the moment and geometrical aberrations and give recommendations on their elimination.

  10. Scanning gamma camera

    International Nuclear Information System (INIS)

    Engdahl, L.W.; Batter, J.F. Jr.; Stout, K.J.

    1977-01-01

    A scanning system for a gamma camera providing for the overlapping of adjacent scan paths is described. A collimator mask having tapered edges provides for a graduated reduction in intensity of radiation received by a detector thereof, the reduction in intensity being graduated in a direction normal to the scanning path to provide a blending of images of adjacent scan paths. 31 claims, 15 figures

  11. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... and Craniofacial Surgery Cleft Lip/Palate and Craniofacial Surgery A cleft lip may require one or more ... find out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment ...

  12. Corrected electrostatic lens systems for ion beams

    International Nuclear Information System (INIS)

    Dalgish, R.L.

    1981-01-01

    Recent work in our laboratory has introduced a new class of electrostatic focus forming element for beams, the ELCO lens. It compares favourably with the electrostatic and magnetic quadrupole elements conventionally used for microbeam formation. The ELCO lens does however have disadvantages associated with apertures and alignment. We have continued with the development of ion beam lenses and have evolved a further class of lens element which eliminates aperture and alignment problems. This new element can be combined like optical lenses into an aberration corrected system. Experimental measurement on the basic lens element has confirmed mathematical analysis of ion trajectories through the element. This mathematical analysis predicts that the basic element can be combined into a corrected lens system for, either: (1) high resolution microprobe formation with intrinsic rastering ability, the spot size limited only by the beam properties; or (2) high quality image formation with large magnification/demagnification ratio and wide angular aperture. (orig.)

  13. Clinical characterization of corneal ectasia after myopic laser in situ keratomileusis based on anterior corneal aberrations and internal astigmatism.

    Science.gov (United States)

    Piñero, David P; Alió, Jorge L; Barraquer, Rafael I; Uceda-Montanes, Antonio; Murta, Joaquim

    2011-07-01

    To evaluate and characterize the clinical features of corneal ectasia after myopic laser in situ keratomileusis (LASIK) considering internal astigmatism and corneal aberrations and their correlation with other clinical data. Vissum-Instituto de Oftalmológico de Alicante, Alicante, Spain. Retrospective comparative case series. In this multicenter study, eyes were divided into 2 groups. The study group comprised eyes that had corneal ectasia after myopic LASIK. The control group comprised eyes that had successful LASIK to correct high myopia. The clinical outcomes were analyzed and compared. Internal astigmatism was calculated using vectorial analysis. The study enrolled 91 eyes (48 study group; 40 control group) of 81 patients (age 18 to 67 years). Uncorrected and corrected (CDVA) distance visual acuities and the refractive status were significantly worse in the study group (P ≤ .01). Corneas in the study group had a significantly higher steepest keratometry (K) reading and a more negative central asphericity (P corneal aberrations were also significantly higher in the study group (P corneal aberrations leading to a visual deterioration were present in eyes with corneal ectasia after myopic LASIK. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  14. Isochronicity correction in the CR storage ring

    International Nuclear Information System (INIS)

    Litvinov, S.; Toprek, D.; Weick, H.; Dolinskii, A.

    2013-01-01

    A challenge for nuclear physics is to measure masses of exotic nuclei up to the limits of nuclear existence which are characterized by low production cross-sections and short half-lives. The large acceptance Collector Ring (CR) [1] at FAIR [2] tuned in the isochronous ion-optical mode offers unique possibilities for measuring short-lived and very exotic nuclides. However, in a ring designed for maximal acceptance, many factors limit the resolution. One point is a limit in time resolution inversely proportional to the transverse emittance. But most of the time aberrations can be corrected and others become small for large number of turns. We show the relations of the time correction to the corresponding transverse focusing and that the main correction for large emittance corresponds directly to the chromaticity correction for transverse focusing of the beam. With the help of Monte-Carlo simulations for the full acceptance we demonstrate how to correct the revolution times so that in principle resolutions of Δm/m=10 −6 can be achieved. In these calculations the influence of magnet inhomogeneities and extended fringe fields are considered and a calibration scheme also for ions with different mass-to-charge ratio is presented

  15. Low aberration monolithic diffraction gratings for high performance optical spectrometers

    Science.gov (United States)

    Triebel, Peter; Moeller, Tobias; Diehl, Torsten; Gatto, Alexandre; Pesch, Alexander; Erdmann, Lars E.; Burkhardt, Matthias; Kalies, Alexander

    2017-09-01

    Gratings are the core element of the spectrometer. For imaging spectrometers beside the polarization sensitivity and efficiency the imaging quality of the diffraction grating is essential. Lenses and mirrors can be produced with lowest wavefront aberrations. Low aberration imaging quality of the grating is required not to limit the overall imaging quality of the instrument. Different types of spectrometers will lead to different requirements on the wavefront aberrations for their specific diffraction gratings. The wavefront aberration of an optical grating is a combination of the substrate wavefront and the grating wavefront. During the manufacturing process of the grating substrate different processes can be applied in order to minimize the wavefront aberrations. The imaging performance of the grating is also optimized due to the recording setup of the holography. This technology of holographically manufactured gratings is used for transmission and reflection gratings on different types of substrates like prisms, convex and concave spherical and aspherical surface shapes, free-form elements. All the manufactured gratings are monolithic and can be coated with high reflection and anti-reflection coatings. Prism substrates were used to manufacture monolithic GRISM elements for the UV to IR spectral range preferably working in transmission. Besides of transmission gratings, numerous spectrometer setups (e.g. Offner, Rowland circle, Czerny-Turner system layout) working on the optical design principles of reflection gratings. The present approach can be applied to manufacture high quality reflection gratings for the EUV to the IR. In this paper we report our latest results on manufacturing lowest wavefront aberration gratings based on holographic processes in order to enable at least diffraction limited complex spectrometric setups over certain wavelength ranges. Beside the results of low aberration gratings the latest achievements on improving efficiency together with

  16. Adult-onset hypogonadotropic hypogonadism caused by aberrant expression of aromatase in an adrenocortical adenocarcinoma.

    Science.gov (United States)

    Advani, Andrew; Johnson, Sarah J; Nicol, Moira R; Papacleovoulou, Georgia; Evans, Dean B; Vaikkakara, Suresh; Mason, J Ian; Quinton, Richard

    2010-01-01

    Estrogen-secreting adrenal cancers are extremely rare, with feminizing symptoms attributed to aromatase expression in the adrenal tumor. We describe a case of hypogonadotropic hypogonadism as a consequence of aberrant aromatase expression in a patient with adrenocortical adenocarcinoma. A 54 year-old man presented with a two month history of gynecomastia and reduced libido. Endocrine biochemistry at presentation showed hypogonadotropic hypogonadism (LH 2.4 U/L, FSH E(1), 821 pmol/L) and estradiol (E(2), 797 pmol/L) and subclinical ACTH-independent hypercortisolism (serum cortisol post 1mg overnight dexamethasone suppression test, 291 nmol/L). A right adrenal mass was identified on CT scanning and the patient underwent an open adrenalectomy. Post-operative evaluation showed normalization of serum levels of E(1) (95 pmol/L), E(2 )(109 pmol/L), testosterone (11.4 nmol/L), LH (4.1 U/L) and FSH (5.9 IU/L), and of cortisol dynamics. Immunohistochemistry of the adrenal cancer confirmed aberrant expression of aromatase in most, although not all, carcinoma cells. Transcripts associated with utilization of promoters II, I.1 and I.3 were prominently represented in the tumor aromatase mRNA. This case highlights that clinical features of feminizing adrenocortical carcinomas can be secondary to estrogen production by aberrantly transcribed and translated aromatase within the tumor. Even in males, gonadotropin secretion is subject to predominantly estrogen-mediated feedback-inhibition. The diagnosis of adrenocortical adenocarcinoma should be considered in men presenting with low testosterone and gonadotropins, particularly in the presence of feminizing features.

  17. Metaphase chromosome aberrations as markers of radiation exposure and dose

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, A.L.; Khan, M.A.; Jostes, R.F.; Cross, F.T.

    1992-10-01

    Chromosome aberration frequency provides the most reliable biological marker of dose for detecting acute accidental radiation exposure. Significant radiation-induced changes in the frequency of chromosome aberrations can be detected at very low doses. Our paper provides information on using molecular chromosome probes paints'' to score chromosome damage and illustrates how technical advances make it possible to understand mechanisms involved during formation of chromosome aberrations. In animal studies chromosome aberrations provide a method to relate cellular damage to cellular dose. Using an In vivo/In vitro approach aberrations provided a biological marker of dose from radon progeny exposure which was used to convert WLM to dose in rat tracheal epithelial cells. Injection of Chinese hamsters with [sup 144]Ce which produced a low dose rate exposure of bone marrow to either low-LET radiation increased the sensitivity of the cells to subsequent external exposure to [sup 60]Co. These studies demonstrated the usefulness of chromosome damage as a biological marker of dose and cellular responsiveness.

  18. Metaphase chromosome aberrations as markers of radiation exposure and dose

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, A.L.; Khan, M.A.; Jostes, R.F.; Cross, F.T.

    1992-10-01

    Chromosome aberration frequency provides the most reliable biological marker of dose for detecting acute accidental radiation exposure. Significant radiation-induced changes in the frequency of chromosome aberrations can be detected at very low doses. Our paper provides information on using molecular chromosome probes ``paints`` to score chromosome damage and illustrates how technical advances make it possible to understand mechanisms involved during formation of chromosome aberrations. In animal studies chromosome aberrations provide a method to relate cellular damage to cellular dose. Using an In vivo/In vitro approach aberrations provided a biological marker of dose from radon progeny exposure which was used to convert WLM to dose in rat tracheal epithelial cells. Injection of Chinese hamsters with {sup 144}Ce which produced a low dose rate exposure of bone marrow to either low-LET radiation increased the sensitivity of the cells to subsequent external exposure to {sup 60}Co. These studies demonstrated the usefulness of chromosome damage as a biological marker of dose and cellular responsiveness.

  19. Radiation-induced cellular reproductive death and chromosome aberrations

    International Nuclear Information System (INIS)

    Bedford, J.S.; Mitchell, J.B.; Griggs, H.G.; Bender, M.A.

    1978-01-01

    If a major mode of cell killing by ionizing radiation is the death of cells containing visible chromosomal aberrations, as for example from anaphase-bridge formation at mitosis, then cells bearing such aberrations should be selectively eliminated from the population, resulting in an increased survival potential for the population remaining at each succeeding cell generation. Using synchronized V79B Chinese hamster cells, we measured the aberration frequency and the colony-forming ability of mitotic cells at each of the first three generations following irradiation in G1. Cells were resynchronized by mechanial harvest at each succeeding mitosis after irradiation in order to avoid mixing of generations in the cell population at later sampling times. As anticipated, the chromosome aberration frequencies decreased markedly from the first to the second and from the second to the third mitosis. The surviving fraction, however, was virtually the same for plating assays carried out immediately after irradiation, at the first, or at the second mitosis. The surviving fraction was significantly higher for cells reaching the third postirradiation mitosis. Survival and aberration frequencies were assayed again at approximately the fourteenth postirradiation division, by which time the irradiated and control populations were not significantly different

  20. Metaphase chromosome aberrations as markers of radiation exposure and dose

    International Nuclear Information System (INIS)

    Brooks, A.L.; Khan, M.A.; Jostes, R.F.; Cross, F.T.

    1992-10-01

    Chromosome aberration frequency provides the most reliable biological marker of dose for detecting acute accidental radiation exposure. Significant radiation-induced changes in the frequency of chromosome aberrations can be detected at very low doses. Our paper provides information on using molecular chromosome probes ''paints'' to score chromosome damage and illustrates how technical advances make it possible to understand mechanisms involved during formation of chromosome aberrations. In animal studies chromosome aberrations provide a method to relate cellular damage to cellular dose. Using an In vivo/In vitro approach aberrations provided a biological marker of dose from radon progeny exposure which was used to convert WLM to dose in rat tracheal epithelial cells. Injection of Chinese hamsters with 144 Ce which produced a low dose rate exposure of bone marrow to either low-LET radiation increased the sensitivity of the cells to subsequent external exposure to 60 Co. These studies demonstrated the usefulness of chromosome damage as a biological marker of dose and cellular responsiveness

  1. Attenuation corrected SPECT using transmission measurements

    International Nuclear Information System (INIS)

    Ziegler, S.I.; Ficaro, E.P.; Boening, G.; Schwaiger, M.

    1996-01-01

    Modern SPECT instrumentation allows attenuation correction in cardiac scans by using transmission measurements. Simultaneous transmission and emission measurements are feasible with different geometries in multihead SPECT systems and are already commercially available. The selection of the transmission nuclide affects the quality of data, depending on the emission nuclide used. Iterative reconstruction methods have to be implemented to get accurate results in the case of heterogeneous attenuation distributions. Methodological aspects concerning simultaneous scatter and attenuation correction have to be studied in future. The clinical significance of routine attenuation correction measurements for myocardial perfusion has to be shown in a large patient population. (orig.) [de

  2. Weak-beam scanning transmission electron microscopy for quantitative dislocation density measurement in steels.

    Science.gov (United States)

    Yoshida, Kenta; Shimodaira, Masaki; Toyama, Takeshi; Shimizu, Yasuo; Inoue, Koji; Yoshiie, Toshimasa; Milan, Konstantinovic J; Gerard, Robert; Nagai, Yasuyoshi

    2017-04-01

    To evaluate dislocations induced by neutron irradiation, we developed a weak-beam scanning transmission electron microscopy (WB-STEM) system by installing a novel beam selector, an annular detector, a high-speed CCD camera and an imaging filter in the camera chamber of a spherical aberration-corrected transmission electron microscope. The capabilities of the WB-STEM with respect to wide-view imaging, real-time diffraction monitoring and multi-contrast imaging are demonstrated using typical reactor pressure vessel steel that had been used in an European nuclear reactor for 30 years as a surveillance test piece with a fluence of 1.09 × 1020 neutrons cm-2. The quantitatively measured size distribution (average loop size = 3.6 ± 2.1 nm), number density of the dislocation loops (3.6 × 1022 m-3) and dislocation density (7.8 × 1013 m m-3) were carefully compared with the values obtained via conventional weak-beam transmission electron microscopy studies. In addition, cluster analysis using atom probe tomography (APT) further demonstrated the potential of the WB-STEM for correlative electron tomography/APT experiments. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. CT scanning in meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Wardle, Stephan; Carty, Helen (Royal Liverpool Children' s Hospital, Liverpool (United Kingdom). Department of Radiology)

    12 pediatric cases of acute meningitis were reviewed retrospectively. Findings on CT scan were compared with the clinical course and resulting neurological sequelae. Complications detected by CT scanning include subdural effusion, empyema, hydrocephalus, cerebral atrophy, oedema and infarction. The CT scan results adequately correlated with neurological signs in most cases. Infarction was a reliable indicator of neurological sequelae. Cerebral atrophy alone, however, did not correlate well with the clinical sequelae. (author). 19 refs.; 5 figs.; 6 tabs.

  4. Spherical aberration and other higher-order aberrations in the human eye : from summary wave-front analysis data to optical variables relevant to visual perception

    NARCIS (Netherlands)

    Jansonius, Nomdo M.

    Wave-front analysis data from the human eye are commonly presented using the aberration coefficient c(4)(0) (primary spherical aberration) together with an overall measure of all higher-order aberrations. If groups of subjects are compared, however, the relevance of an observed difference cannot

  5. Circumflex coronary artery with aberrant origin and atherosclerosis

    International Nuclear Information System (INIS)

    Ozcan, E.; Bozlar, U.; Celik, T.; Tasar, M.

    2012-01-01

    Full text: Introduction: Circumflex (Cx) coronary artery congenital anomaly is reported to be less than 1% incidence. Coronary arteries with aberrant origin are more likely to have atherosclerosis according to some published literatures. Objectives and tasks: In this study we aim to present computed tomography (CT) angiography findings of a patient, who has Cx artery with aberrant origin and atherosclerotic. Materials and methods: 57-year-old woman without any symptoms who has risk factors to atherosclerosis was referred to our clinic for coronary CT angiography. Results: In CT angiography; we detected Cx coronary artery with aberrant origin (right sinus of valsalva) and retroaortic course. Also we saw intimal irregularities and calcified plaque causing severe narrowing in the proximal segment of artery. Right coronary and left anterior descendant arteries had mild atherosclerosis. Conclusion: Coroner CT angiography, which allows multiplanar imaging with high resolution, is an effective diagnostic tool for coronary artery disease, like not only congenital anomalies but also acquired atherosclerotic disease

  6. Biological dosimetry: chromosomal aberration analysis for dose assessment

    International Nuclear Information System (INIS)

    1986-01-01

    In view of the growing importance of chromosomal aberration analysis as a biological dosimeter, the present report provides a concise summary of the scientific background of the subject and a comprehensive source of information at the technical level. After a review of the basic principles of radiation dosimetry and radiation biology basic information on the biology of lymphocytes, the structure of chromosomes and the classification of chromosomal aberrations are presented. This is followed by a presentation of techniques for collecting blood, storing, transporting, culturing, making chromosomal preparations and scaring of aberrations. The physical and statistical parameters involved in dose assessment are discussed and examples of actual dose assessments taken from the scientific literature are given

  7. Screening for aberrant behavior in the nuclear industry

    International Nuclear Information System (INIS)

    Borofsky, G.L.

    1987-01-01

    This paper attempts to promote a fuller understanding of how psychological assessment procedures can be used to reduce the threat from aberrant behavior in the nuclear industry. It begins with a discussion of the scientifically based methods that are used by psychologists in constructing, scoring, and interpreting these procedures. This discussion includes an emphasis on the concepts of validity and reliability and their central importance when one is choosing specific psychological screening tools. Criteria for selecting and using psychological assessment procedures when screening for aberrant behavior are also provided. Some commonly used assessment procedures that satisfy these criteria are discussed. A number a psychological assessment procedures specifically recommended for use in screening for aberrant behavior in the nuclear industry are described

  8. Over-all accuracy of sup(99m)Tc-pertechnetate brain scanning for brain tumours

    International Nuclear Information System (INIS)

    Bjoernsson, O.G.; Petursson, E.; Sigurbjoernsson, B.; Davidsson, D.

    1978-01-01

    A 3-year follow-up and re-evaluation of all scans on all patients referred for brain scanning in Iceland during 1 year was performed in order to assess the diagnostic reliability of radioisotope scanning for brain tumours. The study included 471 patients. Of these 25 had primary brain tumours and 7 brain metastases. Scans were positive and correctly interpreted in 68% of the patients with primary brain tumours and in 3 of the 7 patients with metastases. The over-all accuracy of brain scanning for brain tumours defined as the total number of correct positive scans and correct negative scans versus total number of scans examined was 96%, this figure being mainly influenced by the high number of true negative scans. (orig.) [de

  9. Compensation for longitudinal chromatic aberration in the eye of the firefly squid, Watasenia scintillans.

    Science.gov (United States)

    Kröger, Ronald H H; Gislén, Anna

    2004-01-01

    The camera eyes of fishes and cephalopods have come forth by convergent evolution. In a variety of vertebrates capable of color vision, longitudinal chromatic aberration (LCA) of the optical system is corrected for by the exactly tuned longitudinal spherical aberration (LSA) of the crystalline lens. The LSA leads to multiple focal lengths, such that several wavelengths can be focused on the retina. We investigated whether that is also the case in the firefly squid (Watasenia scintillans), a cephalopod species that is likely to have color vision. It was found that the lens of W. scintillans is virtually free of LSA and uncorrected for LCA. However, the eye does not suffer from LCA because of a banked retina. Photoreceptors sensitive to short and long wavelengths are located at appropriate distances from the lens, such that they receive well-focused images. Such a design is an excellent solution for the firefly squid because a large area of the retina is monochromatically organized and it allows for double use of the surface area in the dichromatically organized part of the retina. However, it is not a universal solution since compensation for LCA by a banked retina requires that eye size and/or spectral separation between photopigments is small.

  10. LIGHT ABERRATION IN OPTICAL ANISOTROPIC SINGLE-AXIS MEDIUM

    Directory of Open Access Journals (Sweden)

    V. M. Svishch

    2017-10-01

    Full Text Available The entrainment of the light flux by a uniaxial anisotropic medium and its influence on the measurement of stellar aberration are analyzed. The influence of the entrainment of the light flux by an isotropic medium on the measurement of stellar aberration was considered by Fresnel early. The absence of such influence was confirmed by Erie's experience when filling the telescope tube with water. The formula itself was perfectly confirmed by Fizeau's experiments with moving water and the repetition of this experiment with an increase in the accuracy of measurements by Michelson, Zeeman, and others. G.A. Lorentz already on the basis of the electromagnetic theory specified the formula with allowance for the frequency dispersion of the light flux. A. Einstein made an analysis of the schemes of experiments for determining the drag coefficient, covering all possible variants of similar experiments. As a result, he obtained Fresnel and Lorentz formulas, taking into account the frequency dispersion of light, starting from the theory of relativity. The entrainment of light and its influence on the measurement of stellar aberration by a uniaxial anisotropic medium have not been considered anywhere. An analysis of such influence is carried out. The results of the analysis indicate the possibility of measuring the current value of stellar aberration using a uniaxial anisotropic medium. The concept of active light aberration is introduced. The proposed schemes of experiments of using the entrainment of a light flux by an anisotropic substance for measuring the current value of stellar aberration are investigated. It is concluded that it is possible to study the determination of the current velocity of an inertial system relative to the light flux.

  11. Absence of orthotopic renal vein with aberrant suprarenal venous drainage; A case report

    International Nuclear Information System (INIS)

    Kim, Eu gene; Jeon, Yong Sun; Cho, Soon Gu; Hong, Kee Chun; Park, Keun Myung; Lee, Tack

    2015-01-01

    A CT scan of a 49-year-old female incidentally revealed a tortuous vascular structure in the right suprarenal space. According to angiographic evaluation of the right renal vessels, the right renal artery was single with normal diameter, and there was no venous drainage through the main right renal vein (orthotopic renal vein). The venous drainage of the right kidney flowed through the tortuous suprarenal vascular structure into the inferior vena cava. The color Doppler ultrasound revealed the monophasic waveform in that vascular structure without flow disturbance. The renal function and the result of urinalysis of the patient were normal, and any other congenital malformation was not found. Absence of the orthotopic renal vein and aberrant suprarenal venous drainage is a very rare congenital anomaly, and it should be discriminated from the other pathologic conditions

  12. Absence of orthotopic renal vein with aberrant suprarenal venous drainage; A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eu gene; Jeon, Yong Sun; Cho, Soon Gu; Hong, Kee Chun; Park, Keun Myung; Lee, Tack [Inha University Hospital, Incheon (Korea, Republic of)

    2015-06-15

    A CT scan of a 49-year-old female incidentally revealed a tortuous vascular structure in the right suprarenal space. According to angiographic evaluation of the right renal vessels, the right renal artery was single with normal diameter, and there was no venous drainage through the main right renal vein (orthotopic renal vein). The venous drainage of the right kidney flowed through the tortuous suprarenal vascular structure into the inferior vena cava. The color Doppler ultrasound revealed the monophasic waveform in that vascular structure without flow disturbance. The renal function and the result of urinalysis of the patient were normal, and any other congenital malformation was not found. Absence of the orthotopic renal vein and aberrant suprarenal venous drainage is a very rare congenital anomaly, and it should be discriminated from the other pathologic conditions.

  13. Investigation of spherical aberration effects on coherent lidar performance

    DEFF Research Database (Denmark)

    Hu, Qi; Rodrigo, Peter John; Iversen, Theis Faber Quist

    2013-01-01

    In this paper we demonstrate experimentally the performance of a monostatic coherent lidar system under the influence of phase aberrations, especially the typically predominant spherical aberration (SA). The performance is evaluated by probing the spatial weighting function of the lidar system...... with different telescope configurations using a hard target. It is experimentally and numerically proven that the SA has a significant impact on lidar antenna efficiency and optimal beam truncation ratio. Furthermore, we demonstrate that both effective probing range and spatial resolution of the system...

  14. [Prenatal diagnostics of chromosomal aberrations Czech Republic: 1994-2007].

    Science.gov (United States)

    Gregor, V; Sípek, A; Sípek, A; Horácek, J '; Langhammer, P; Petrzílková, L; Calda, P

    2009-02-01

    An analysis of prenatal diagnostics efficiency of selected types of chromosomal aberrations in the Czech Republic in 2007. Update of 1994-2007 data according to particular selected diagnoses. Retrospective epidemiological analysis of pre- and postnatal chromosomal aberrations diagnostics and its efficiency. Data on pre- and postnatally diagnosed birth defects in the Czech Republic during 1994-2007 were used. Data on prenatally diagnosed birth defects (and for terminated pregnancies) were collected from particular departments of prenatal diagnostics, medical genetics and ultrasound diagnostics in the Czech Republic, data on birth defects in births from the National Birth Defects Register (Institute for Health Information and Statistics). Total numbers over the period under the study, mean incidences of selected types of chromosomal aberrations and mean prenatal diagnostics efficiencies were analyzed. Following chromosomal aberrations were studied: Down, Edwards, Patau, Turner and Klinefelter syndromes and syndromes 47,XXX and 47,XYY. A relative proportion of Down, Edwards and Patau syndromes as well as other autosomal and gonosomal aberration is presented in figures. Recently, trisomies 13, 18 and 21 present around 70% of all chromosomal aberrations in selectively aborted fetuses, in other pregnancies, "other chromosomal aberrations" category (mostly balanced reciprocal translocations and inversions) present more than 2/3 of all diagnoses. During the period under the study, following total numbers, mean relative incidences (per 10,000 live births, in brackets) and mean prenatal diagnostics efficiency (in %) were found in following chromosomal syndromes: Down syndrome 2,244 (16.58) and 63.37%, Edwards syndrome 521 (3.85) and 79.93%, Patau syndrome 201 (1.49) and 68.87%, Turner syndrome 380 (2.81) and 79.89%, 47,XXX syndrome 61 (0.45) and 59.74%, Klinefelter syndrome 163 (1.20) and 73.65% and 47,XYY syndrome 22 (0.16) and 54.76%. The study gives updated results of

  15. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan and uptake uses ...

  16. Model PET Scan Activity

    Science.gov (United States)

    Strunk, Amber; Gazdovich, Jennifer; Redouté, Oriane; Reverte, Juan Manuel; Shelley, Samantha; Todorova, Vesela

    2018-05-01

    This paper provides a brief introduction to antimatter and how it, along with other modern physics topics, is utilized in positron emission tomography (PET) scans. It further describes a hands-on activity for students to help them gain an understanding of how PET scans assist in detecting cancer. Modern physics topics provide an exciting way to introduce students to current applications of physics.

  17. Scanning laser Doppler vibrometry

    DEFF Research Database (Denmark)

    Brøns, Marie; Thomsen, Jon Juel

    With a Scanning Laser Doppler Vibrometer (SLDV) a vibrating surface is automatically scanned over predefined grid points, and data processed for displaying vibration properties like mode shapes, natural frequencies, damping ratios, and operational deflection shapes. Our SLDV – a PSV-500H from...

  18. Transverse section scanning mechanism

    International Nuclear Information System (INIS)

    Doherty, E.J.

    1978-01-01

    Apparatus is described for scanning a transverse, radionuclide scan-field using an array of focussed collimators. The collimators are movable tangentially on rails, driven by a single motor via a coupled screw. The collimators are also movable in a radial direction on rails driven by a step motor via coupled screws and bevel gears. Adjacent bevel gears rotate in opposite directions so adjacent collimators move in radially opposite directions. In use, the focal point of each collimator scans at least half of the scan-field, e.g. a human head located in the central aperture, and the electrical outputs of detectors associated with each collimator are used to determine the distribution of radioactive emission intensity at a number of points in the scan-field. (author)

  19. Beam scanning system

    International Nuclear Information System (INIS)

    Enge, H.A.

    1977-01-01

    A system for deflecting a beam of particles having different momenta, preferably through a 90 0 angle, so as to cause the beam to impinge upon a moving target and to scan across the target is described. The system includes a means responsive to a beam from a suitable source for causing the beam to periodically scan in a scanning plane and further means for deflecting the periodically scanned beam through the desired angle in a deflection plane so that the deflected beam impinges on the target. Means are included in the system for reducing the momentum dispersion at the target in both the deflection and the scanning planes and for spatially focussing the beam so as to produce a desired beam diameter at the target

  20. Topography and Higher Order Corneal Aberrations of the Fellow Eye in Unilateral Keratoconus.

    Science.gov (United States)

    Aksoy, Sibel; Akkaya, Sezen; Özkurt, Yelda; Kurna, Sevda; Açıkalın, Banu; Şengör, Tomris

    2017-10-01

    Comparison of topography and corneal higher order aberrations (HOA) data of fellow normal eyes of unilateral keratoconus patients with keratoconus eyes and control group. The records of 196 patients with keratoconus were reviewed. Twenty patients were identified as unilateral keratoconus. The best corrected visual acuity (BCVA), topography and aberration data of the unilateral keratoconus patients' normal eyes were compared with their contralateral keratoconus eyes and with control group eyes. For statistical analysis, flat and steep keratometry values, average corneal power, cylindrical power, surface regularity index (SRI), surface asymmetry index (SAI), inferior-superior ratio (I-S), keratoconus prediction index, and elevation-depression power (EDP) and diameter (EDD) topography indices were selected. Mean age of the unilateral keratoconus patients was 26.05±4.73 years and that of the control group was 23.6±8.53 years (p>0.05). There was no statistical difference in BCVA between normal and control eyes (p=0.108), whereas BCVA values were significantly lower in eyes with keratoconus (p=0.001). Comparison of quantitative topographic indices between the groups showed that all indices except the I-S ratio were significantly higher in the normal group than in the control group (p<0.05). The most obvious differences were in the SRI, SAI, EDP, and EDD values. All topographic indices were higher in the keratoconus eyes compared to the normal fellow eyes. There was no difference between normal eyes and the control group in terms of spherical aberration, while coma, trefoil, irregular astigmatism, and total HOA values were higher in the normal eyes of unilateral keratoconus patients (p<0.05). All HOA values were higher in keratoconus eyes than in the control group. According to our study, SRI, SAI, EDP, EDD values, and HOA other than spherical aberration were higher in the clinically and topographically normal fellow eyes of unilateral keratoconus patients when compared

  1. Chromosomal Aberrations in DNA Repair Defective Cell Lines: Comparisons of Dose Rate and Radiation Quality

    Science.gov (United States)

    George, K. A.; Hada, M.; Patel, Z.; Huff, J.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Chromosome aberration yields were assessed in DNA double-strand break repair (DSB) deficient cells after acute doses of gamma-rays or high-LET iron nuclei, or low dose-rate (0.018 Gy/hr) gamma-rays. We studied several cell lines including fibroblasts deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase, DNA-PK activity. Chromosomes were analyzed using the fluorescence in-situ hybridization (FISH) chromosome painting method in cells at the first division post-irradiation and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma radiation induced higher yields of both simple and complex exchanges in the DSB repair defective cells than in the normal cells. The quadratic dose-response terms for both chromosome exchange types were significantly higher for the ATM and NBS defective lines than for normal fibroblasts. However, the linear dose-response term was significantly higher only for simple exchanges in the NBS cells. Large increases in the quadratic dose response terms indicate the important roles of ATM and NBS in chromatin modifications that facilitate correct DSB repair and minimize aberration formation. Differences in the response of AT and NBS deficient cells at lower doses suggests important questions about the applicability of observations of radiation sensitivity at high dose to low dose exposures. For all iron nuclei irradiated cells, regression models preferred purely linear and quadratic dose responses for simple and complex exchanges, respectively. All the DNA repair defective cell lines had lower Relative biological effectiveness (RBE) values than normal cells, the lowest being for the DNA-PK-deficient cells, which was near unity. To further

  2. LIDAR COMBINED SCANNING UNIT

    Directory of Open Access Journals (Sweden)

    V. V. Elizarov

    2016-11-01

    Full Text Available Subject of Research. The results of lidar combined scanning unit development for locating leaks of hydrocarbons are presented The unit enables to perform high-speed scanning of the investigated space in wide and narrow angle fields. Method. Scanning in a wide angular field is produced by one-line scanning path by means of the movable aluminum mirror with a frequency of 20Hz and amplitude of 20 degrees of swing. Narrowband scanning is performed along a spiral path by the deflector. The deflection of the beam is done by rotation of the optical wedges forming part of the deflector at an angle of ±50. The control function of the scanning node is performed by a specialized software product written in C# programming language. Main Results. This scanning unit allows scanning the investigated area at a distance of 50-100 m with spatial resolution at the level of 3 cm. The positioning accuracy of the laser beam in space is 15'. The developed scanning unit gives the possibility to browse the entire investigated area for the time not more than 1 ms at a rotation frequency of each wedge from 50 to 200 Hz. The problem of unambiguous definition of the beam geographical coordinates in space is solved at the software level according to the rotation angles of the mirrors and optical wedges. Lidar system coordinates are determined by means of GPS. Practical Relevance. Development results open the possibility for increasing the spatial resolution of scanning systems of a wide range of lidars and can provide high positioning accuracy of the laser beam in space.

  3. Detector correction in large container inspection systems

    CERN Document Server

    Kang Ke Jun; Chen Zhi Qiang

    2002-01-01

    In large container inspection systems, the image is constructed by parallel scanning with a one-dimensional detector array with a linac used as the X-ray source. The linear nonuniformity and nonlinearity of multiple detectors and the nonuniform intensity distribution of the X-ray sector beam result in horizontal striations in the scan image. This greatly impairs the image quality, so the image needs to be corrected. The correction parameters are determined experimentally by scaling the detector responses at multiple points with logarithm interpolation of the results. The horizontal striations are eliminated by modifying the original image data with the correction parameters. This method has proven to be effective and applicable in large container inspection systems

  4. Novel plumage aberrations in Paraguayan non-Passerine Birds, and the definition of a new plumage aberration unique to Psittacidae

    Directory of Open Access Journals (Sweden)

    Paul Smith

    2017-07-01

    Full Text Available Anomalous plumage colourations are reported for three species of non-passerine birds from Paraguay, Limpkin (Aramaus guarauna; Aramidae, Nanday Parakeet (Nandayus nenday; Psittacidae, and the Little Woodpecker (Veniliornis passerinus; Picidae. A leucistic Limpkin is the first published report of a colour anomaly for the family Aramidae. The colour aberration in N. nenday is hypothesised to be a result of an excess of red psittacofulvin pigments, which are unique to the Psittacidae. Although the mechanisms causing this colour aberration remain unknown, we suggest the term psittacofulvism for the phenotypic effect observed.

  5. Differential algebraic method for arbitrary order curvilinear-axis combined geometric-chromatic aberration analysis

    CERN Document Server

    Cheng Min; Lu Yi Long; Yao Zhen Hua

    2003-01-01

    The principle of differential algebra is applied to analyse and calculate arbitrary order curvilinear-axis combined geometric-chromatic aberrations of electron optical systems. Expressions of differential algebraic form of high order combined aberrations are obtained and arbitrary order combined aberrations can be calculated numerically. As an example, a typical wide electron beam focusing system with curved optical axes named magnetic immersion lens has been studied. All the second-order and third-order combined geometric-chromatic aberrations of the lens have been calculated, and the patterns of the corresponding geometric aberrations and combined aberrations have been given as well.

  6. Aberration of a negative ion beam caused by space charge effect.

    Science.gov (United States)

    Miyamoto, K; Wada, S; Hatayama, A

    2010-02-01

    Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

  7. Genome-wide scan of healthy human connectome discovers SPON1 gene variant influencing dementia severity

    Science.gov (United States)

    Jahanshad, Neda; Rajagopalan, Priya; Hua, Xue; Hibar, Derrek P.; Nir, Talia M.; Toga, Arthur W.; Jack, Clifford R.; Saykin, Andrew J.; Green, Robert C.; Weiner, Michael W.; Medland, Sarah E.; Montgomery, Grant W.; Hansell, Narelle K.; McMahon, Katie L.; de Zubicaray, Greig I.; Martin, Nicholas G.; Wright, Margaret J.; Thompson, Paul M.; Weiner, Michael; Aisen, Paul; Weiner, Michael; Aisen, Paul; Petersen, Ronald; Jack, Clifford R.; Jagust, William; Trojanowski, John Q.; Toga, Arthur W.; Beckett, Laurel; Green, Robert C.; Saykin, Andrew J.; Morris, John; Liu, Enchi; Green, Robert C.; Montine, Tom; Petersen, Ronald; Aisen, Paul; Gamst, Anthony; Thomas, Ronald G.; Donohue, Michael; Walter, Sarah; Gessert, Devon; Sather, Tamie; Beckett, Laurel; Harvey, Danielle; Gamst, Anthony; Donohue, Michael; Kornak, John; Jack, Clifford R.; Dale, Anders; Bernstein, Matthew; Felmlee, Joel; Fox, Nick; Thompson, Paul; Schuff, Norbert; Alexander, Gene; DeCarli, Charles; Jagust, William; Bandy, Dan; Koeppe, Robert A.; Foster, Norm; Reiman, Eric M.; Chen, Kewei; Mathis, Chet; Morris, John; Cairns, Nigel J.; Taylor-Reinwald, Lisa; Trojanowki, J.Q.; Shaw, Les; Lee, Virginia M.Y.; Korecka, Magdalena; Toga, Arthur W.; Crawford, Karen; Neu, Scott; Saykin, Andrew J.; Foroud, Tatiana M.; Potkin, Steven; Shen, Li; Khachaturian, Zaven; Frank, Richard; Snyder, Peter J.; Molchan, Susan; Kaye, Jeffrey; Quinn, Joseph; Lind, Betty; Dolen, Sara; Schneider, Lon S.; Pawluczyk, Sonia; Spann, Bryan M.; Brewer, James; Vanderswag, Helen; Heidebrink, Judith L.; Lord, Joanne L.; Petersen, Ronald; Johnson, Kris; Doody, Rachelle S.; Villanueva-Meyer, Javier; Chowdhury, Munir; Stern, Yaakov; Honig, Lawrence S.; Bell, Karen L.; Morris, John C.; Ances, Beau; Carroll, Maria; Leon, Sue; Mintun, Mark A.; Schneider, Stacy; Marson, Daniel; Griffith, Randall; Clark, David; Grossman, Hillel; Mitsis, Effie; Romirowsky, Aliza; deToledo-Morrell, Leyla; Shah, Raj C.; Duara, Ranjan; Varon, Daniel; Roberts, Peggy; Albert, Marilyn; Onyike, Chiadi; Kielb, Stephanie; Rusinek, Henry; de Leon, Mony J.; Glodzik, Lidia; De Santi, Susan; Doraiswamy, P. Murali; Petrella, Jeffrey R.; Coleman, R. Edward; Arnold, Steven E.; Karlawish, Jason H.; Wolk, David; Smith, Charles D.; Jicha, Greg; Hardy, Peter; Lopez, Oscar L.; Oakley, MaryAnn; Simpson, Donna M.; Porsteinsson, Anton P.; Goldstein, Bonnie S.; Martin, Kim; Makino, Kelly M.; Ismail, M. Saleem; Brand, Connie; Mulnard, Ruth A.; Thai, Gaby; Mc-Adams-Ortiz, Catherine; Womack, Kyle; Mathews, Dana; Quiceno, Mary; Diaz-Arrastia, Ramon; King, Richard; Weiner, Myron; Martin-Cook, Kristen; DeVous, Michael; Levey, Allan I.; Lah, James J.; Cellar, Janet S.; Burns, Jeffrey M.; Anderson, Heather S.; Swerdlow, Russell H.; Apostolova, Liana; Lu, Po H.; Bartzokis, George; Silverman, Daniel H.S.; Graff-Radford, Neill R.; Parfitt, Francine; Johnson, Heather; Farlow, Martin R.; Hake, Ann Marie; Matthews, Brandy R.; Herring, Scott; van Dyck, Christopher H.; Carson, Richard E.; MacAvoy, Martha G.; Chertkow, Howard; Bergman, Howard; Hosein, Chris; Black, Sandra; Stefanovic, Bojana; Caldwell, Curtis; Hsiung, Ging-Yuek Robin; Feldman, Howard; Mudge, Benita; Assaly, Michele; Kertesz, Andrew; Rogers, John; Trost, Dick; Bernick, Charles; Munic, Donna; Kerwin, Diana; Mesulam, Marek-Marsel; Lipowski, Kristina; Wu, Chuang-Kuo; Johnson, Nancy; Sadowsky, Carl; Martinez, Walter; Villena, Teresa; Turner, Raymond Scott; Johnson, Kathleen; Reynolds, Brigid; Sperling, Reisa A.; Johnson, Keith A.; Marshall, Gad; Frey, Meghan; Yesavage, Jerome; Taylor, Joy L.; Lane, Barton; Rosen, Allyson; Tinklenberg, Jared; Sabbagh, Marwan; Belden, Christine; Jacobson, Sandra; Kowall, Neil; Killiany, Ronald; Budson, Andrew E.; Norbash, Alexander; Johnson, Patricia Lynn; Obisesan, Thomas O.; Wolday, Saba; Bwayo, Salome K.; Lerner, Alan; Hudson, Leon; Ogrocki, Paula; Fletcher, Evan; Carmichael, Owen; Olichney, John; DeCarli, Charles; Kittur, Smita; Borrie, Michael; Lee, T.-Y.; Bartha, Rob; Johnson, Sterling; Asthana, Sanjay; Carlsson, Cynthia M.; Potkin, Steven G.; Preda, Adrian; Nguyen, Dana; Tariot, Pierre; Fleisher, Adam; Reeder, Stephanie; Bates, Vernice; Capote, Horacio; Rainka, Michelle; Scharre, Douglas W.; Kataki, Maria; Zimmerman, Earl A.; Celmins, Dzintra; Brown, Alice D.; Pearlson, Godfrey D.; Blank, Karen; Anderson, Karen; Saykin, Andrew J.; Santulli, Robert B.; Schwartz, Eben S.; Sink, Kaycee M.; Williamson, Jeff D.; Garg, Pradeep; Watkins, Franklin; Ott, Brian R.; Querfurth, Henry; Tremont, Geoffrey; Salloway, Stephen; Malloy, Paul; Correia, Stephen; Rosen, Howard J.; Miller, Bruce L.; Mintzer, Jacobo; Longmire, Crystal Flynn; Spicer, Kenneth; Finger, Elizabeth; Rachinsky, Irina; Rogers, John; Kertesz, Andrew; Drost, Dick

    2013-01-01

    Aberrant connectivity is implicated in many neurological and psychiatric disorders, including Alzheimer’s disease and schizophrenia. However, other than a few disease-associated candidate genes, we know little about the degree to which genetics play a role in the brain networks; we know even less about specific genes that influence brain connections. Twin and family-based studies can generate estimates of overall genetic influences on a trait, but genome-wide association scans (GWASs) can screen the genome for specific variants influencing the brain or risk for disease. To identify the heritability of various brain connections, we scanned healthy young adult twins with high-field, high-angular resolution diffusion MRI. We adapted GWASs to screen the brain’s connectivity pattern, allowing us to discover genetic variants that affect the human brain’s wiring. The association of connectivity with the SPON1 variant at rs2618516 on chromosome 11 (11p15.2) reached connectome-wide, genome-wide significance after stringent statistical corrections were enforced, and it was replicated in an independent subsample. rs2618516 was shown to affect brain structure in an elderly population with varying degrees of dementia. Older people who carried the connectivity variant had significantly milder clinical dementia scores and lower risk of Alzheimer’s disease. As a posthoc analysis, we conducted GWASs on several organizational and topological network measures derived from the matrices to discover variants in and around genes associated with autism (MACROD2), development (NEDD4), and mental retardation (UBE2A) significantly associated with connectivity. Connectome-wide, genome-wide screening offers substantial promise to discover genes affecting brain connectivity and risk for brain diseases. PMID:23471985

  8. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... more surgeries depending on the extent of the repair needed. Click here to find out more. Corrective ... more surgeries depending on the extent of the repair needed. Click here to find out more. Corrective ...

  9. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... Jaw Surgery Download Download the ebook for further information Corrective jaw, or orthognathic surgery is performed by ... your treatment. Correction of Common Dentofacial Deformities ​ ​ The information provided here is not intended as a substitute ...

  10. NWS Corrections to Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Form B-14 is the National Weather Service form entitled 'Notice of Corrections to Weather Records.' The forms are used to make corrections to observations on forms...

  11. Adaptive optics correction based on stochastic parallel gradient descent technique using Zernike polynomials

    Science.gov (United States)

    Ma, Huimin; Qiao, Yan; Shen, Chunshan

    2017-10-01

    Adaptive optics systems based on stochastic parallel gradient descent optimization (SPGD) have yet shown great potential on compensation of phase distortions induced by wave propagation through atmosphere turbulence. One of the key technique is increasing the converge rate of SPGD correction system. In the present study, it is shown that the convergence rate of the algorithm will be greatly reduced with the increase of the number of corrector units. In this paper, an improved SPGD optimization process which is based on Zernike-mode is developed. The optimized object is changed from the voltage to Zernike coefficient. Adaptive optics correction system simulation model base on SPGD for a laser beam projecting system, and the numerical simulation of compensation process of random atmosphere turbulence is proposed. To improve the converge speed, we explore to ameliorate the correction system by controlling the perturbation considering atmosphere aberration proportion. The results show that the system converges smoothly and increasingly after considering the aberration proportion by Zernike correction.

  12. Increasing the field of view of adaptive optics scanning laser ophthalmoscopy.

    Science.gov (United States)

    Laslandes, Marie; Salas, Matthias; Hitzenberger, Christoph K; Pircher, Michael

    2017-11-01

    An adaptive optics scanning laser ophthalmoscope (AO-SLO) set-up with two deformable mirrors (DM) is presented. It allows high resolution imaging of the retina on a 4°×4° field of view (FoV), considering a 7 mm pupil diameter at the entrance of the eye. Imaging on such a FoV, which is larger compared to classical AO-SLO instruments, is allowed by the use of the two DMs. The first DM is located in a plane that is conjugated to the pupil of the eye and corrects for aberrations that are constant in the FoV. The second DM is conjugated to a plane that is located ∼0.7 mm anterior to the retina. This DM corrects for anisoplanatism effects within the FoV. The control of the DMs is performed by combining the classical AO technique, using a Shack-Hartmann wave-front sensor, and sensorless AO, which uses a criterion characterizing the image quality. The retinas of four healthy volunteers were imaged in-vivo with the developed instrument. In order to assess the performance of the set-up and to demonstrate the benefits of the 2 DM configuration, the acquired images were compared with images taken in conventional conditions, on a smaller FoV and with only one DM. Moreover, an image of a larger patch of the retina was obtained by stitching of 9 images acquired with a 4°×4° FoV, resulting in a total FoV of 10°×10°. Finally, different retinal layers were imaged by shifting the focal plane.

  13. Chromosomal aberrations in tire plant workers and interaction with

    Czech Academy of Sciences Publication Activity Database

    Musak, L.; Souček, P.; Vodičková, Ludmila; Naccarati, Alessio; Halasová, E.; Poláková, Veronika; Slyšková, Jana; Susová, S.; Buchancová, J.; Šmerhovský, Z.; Sediková, J.; Klimentová, G.; Osina, O.; Hemminki, K.; Vodička, Pavel

    2008-01-01

    Roč. 641, 1-2 (2008), s. 36-42 ISSN 0027-5107 R&D Projects: GA MZd NR8563 Institutional research plan: CEZ:AV0Z50390512 Keywords : Chromosomal aberrations * Genetic polymorphisms * DNA repair genes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.198, year: 2008

  14. Aberrant Right Subclavian Artery: A Life‑threatening Anomaly that ...

    African Journals Online (AJOL)

    ARCA, who suffered concurrently from esophageal cancer. CASE REPORT. The patient was a 56-year-old ... concurrent aberrant subclavian artery and esophageal cancer. The transhiatal esophagectomy was ... Department of Surgery, Imam Khomeini Training Hospital,. Urmia University of Medical Sciences, Ershad ...

  15. Detecting and explaining aberrant responding on the Outcome Questionnaire-45

    NARCIS (Netherlands)

    Conijn, J.M.; Emons, W.H.M.; de Jong, K.; Sijtsma, K.

    2015-01-01

    We applied item response theory based person-fit analysis (PFA) to data of the Outcome Questionnaire-45 (OQ-45) to investigate the prevalence and causes of aberrant responding in a sample of Dutch clinical outpatients. The Formula person-fit statistic was used to detect misfitting item-score

  16. New trends and techniques in chromosome aberration analysis

    International Nuclear Information System (INIS)

    Bender, M.A.

    1978-01-01

    The following topics are discussed: automation of chromosome analysis; storage of fixed cells from cultures of lymphocytes obtained routinely during periodic employee medical examinations; analysis of banded chromosomes; identification of first division metaphases; sister chromatid exchange; and patterns of aberration induction

  17. Testicular artery arising from an aberrant right renal artery | Suluba ...

    African Journals Online (AJOL)

    This case report we discovered the rare variation of the origin of the right testicular artery arising from the right aberrant renal artery with double renal artery irrigating both left and right kidneys. These variations in the testicular arteries and renal arteries have implication to surgical procedures such as orchidopexy repair for ...

  18. Iatrogenic injury of an aberrant right posterior sectoral bile duct

    African Journals Online (AJOL)

    (Figs 1 and 2). A week later, an endoscopic retrograde cholangiopancreatography. (ERCP) examination was performed. This showed no filling of the right posterior sectoral ducts but normal opacification of the other ducts. (Figs 3a and b). These findings led to the diagnosis of an aberrant right posterior sectoral bile duct that ...

  19. Expressions for third-order aberration theory for holographic images

    Indian Academy of Sciences (India)

    Expressions for third-order aberration theory for holographic images. S K TRIPATHY and S ANANDA RAO. Department of Physics, Jagannath Institute for Technology and Management,. Parlakhemundi 761 200, India. Email: sukantatripathy@sify.com. MS received 14 September 2001; revised 5 August 2002. Abstract.

  20. Chromosomal aberrations and SCEs as biomarkers of cancer risk

    Czech Academy of Sciences Publication Activity Database

    Norppa, H.; Bonassi, S.; Hansteen, I. L.; Hagmar, L.; Strömberg, U.; Rössner st., Pavel; Boffetta, P.; Lindholm, C.; Gundy, S.; Lazutka, J.; Cebulska-Wasilewska, A.; Fabiánová, E.; Šrám, Radim; Knudsen, L. E.; Barale, R.; Fucic, A.

    2006-01-01

    Roč. 600, - (2006), s. 37-45 ISSN 0027-5107 Institutional research plan: CEZ:AV0Z50390512 Keywords : biomarkers * chromosomal aberration * sister chromatid exchange Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.111, year: 2006

  1. Aberrant behavior of preschool children: Evaluation of questionnaire

    Directory of Open Access Journals (Sweden)

    Fajgelj Stanislav

    2007-01-01

    Full Text Available In the study metric characteristics of children aberrant behavior questionnaire were analyzed. The analysis was performed on the sample of 1.165 children, aged 4-7, in preschool institutions in several towns of Vojvodina. The questionnaire contained 36 items of the Likert-type scale and was filled in by one parent of each child. The authors examined main metric characteristics of the complete questionnaire, as well as individual items under the Rasche’s measurement model. Generally, parents seldom notice aberrant behavior in their children. Most frequently they notice stubbornness, while very rarely torturing of animals. The item discrimination, on the whole, was found satisfying. The reliability of the questionnaire is 0.84., and all indicators of misfit are within satisfactory ranges. According to differential functioning of the items, the authors found gender and age specificities of parents’ evaluation of aberrant behavior of their children. Parents often notice stubbornness and moldiness in girls, and aggression in boys. According to the parent’s observations, younger children are characterized by nail nibbling, ticklishness, and fearfulness, whereas older children show a tendency to force their way by crying, waywardness and bed-wetting. By means of factor analysis of the items, three principal facets of aberrant behavior were determined: overindulgence, shyness and quarrelsomeness. Cross validation (hold out showed that these three facets were robust in relation to the selection of the sample.

  2. Consequences of Aberrant Hedgehog Signaling During Zebrafish Development

    NARCIS (Netherlands)

    Koudijs, M.J.

    2007-01-01

    The Hedgehog signaling pathway is controlling proliferation, patterning and differentiation during development of vertebrates and invertebrates. Aberrant Hedgehog activity has been shown to be one of the underlying causes of a number of congenital disorders and multiple types of cancer. We

  3. Aberrant Right Subclavian Artery: A Life‑threatening Anomaly that ...

    African Journals Online (AJOL)

    Aberrant right subclavian artery (ARSA) is a rare anomaly, in which the right subclavian artery arises directly from the aortic arch instead of originating from the brachiocephalic artery. This anomaly should be taken into consideration during surgical procedures around esophagus, such as esophagectomy. Any unintentional ...

  4. Thermally induced lensing determination from the coefficient of defocus aberration

    CSIR Research Space (South Africa)

    Bell, Teboho

    2014-07-01

    Full Text Available The effects of a temperature gradient in a laser crystal in an end-pumped configuration in a solid-state laser resonator results in thermally induced aberrations. Of particular interest we measure the thermally induced lens from the coefficient...

  5. Splicing aberrations caused by constitutional RB1 gene mutations in ...

    Indian Academy of Sciences (India)

    . [Parsam VL, Ali MJ, Honavar SG, Vemuganti GK and Kannabiran C 2011 Splicing aberrations caused by constitutional RB1 gene mutations in retinoblastoma. J. Biosci. 36 281–287] DOI 10.1007/s12038-011-9062-9. 1. Introduction.

  6. Telomere Length in Circulating Lymphocytes: Association with Chromosomal Aberrations

    Czech Academy of Sciences Publication Activity Database

    Hemminki, K.; Rachakonda, S.; Musak, L.; Vymetálková, Veronika; Halasová, E.; Forsti,, A.; Vodičková, Ludmila; Buchancová, J.; Vodička, Pavel; Kumar, R.

    2015-01-01

    Roč. 54, č. 3 (2015), s. 194-196 ISSN 1045-2257 Institutional support: RVO:68378041 Keywords : structural chromosome aberrations * healthy subjects * relative telomere length * genotoxicity * telomere biology Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.960, year: 2015

  7. The Aberrant Salience Inventory: A New Measure of Psychosis Proneness

    Science.gov (United States)

    Cicero, David C.; Kerns, John G.; McCarthy, Denis M.

    2010-01-01

    Aberrant salience is the unusual or incorrect assignment of salience, significance, or importance to otherwise innocuous stimuli and has been hypothesized to be important for psychosis and psychotic disorders such as schizophrenia. Despite the importance of this concept in psychosis research, no questionnaire measures are available to assess…

  8. Frequency of primary amenorrhea due to chromosomal aberration

    International Nuclear Information System (INIS)

    Jabbar, S.

    2004-01-01

    Objective: To find out the frequency of primary amenorrhea due to chromosomal aberration and the different options available for management. Subjects and Methods: All patients with primary amenorrhea due to chromosomal aberrations were included in study. Patient's detailed history, general physical examination, presence or absence of secondary sexual characteristics, abdominal and pelvic examination finding were noted. Targeted investigations, including ultrasound, hormonal assay, buccal smear and karyotyping results were recorded. The management options were individually tailored with focus n psychological management. Results: Eighteen patients out of 30,000 patients were diagnosed as having primary amenorrhea. Six had primary amenorrhea due to chromosomal aberrations with the frequency of 0.02%. The age at presentation was 20 years and above in 50%. The most common cause was Turner's syndrome seen in 4 out of 6. The presenting symptoms were delay in onset of menstruation in 05 patients and primary infertility in 01 patient. Conclusion: Primary amenorrhea due to chromosomal aberration is an uncommon condition requiring an early and accurate diagnosis. Turner's syndrome is a relatively common cause of this condition. Management should be multi-disciplinary and individualized according to the patient's age and symptom at presentation. Psychological management is very important and counselling throughout treatment is recommended. (author)

  9. The double monochromator geometric theory and compensation of aberrations

    NARCIS (Netherlands)

    Sokolova, E.; Mogo, S.

    2001-01-01

    The light path function for the double monochromator is constructed, and the formulas of account of the members of its expanding in ascending power series adequate for the defocusing and the first order astigmatism aberrations are found. On the basis of results of the minimisation of obtained

  10. Spherical aberration from trajectories in real and hard-edge ...

    Indian Academy of Sciences (India)

    Abstract. For analytical, real and hard-edge solenoidal axial magnetic fields, the low-energy electron trajectories are obtained using the third-order paraxial ray equation. Using the particle trajectories, it is shown that the spherical aberration in the hard-edge model is high and it increases monotonously with hard edginess, ...

  11. Oxidative stress and chromosomal aberrations in an environmentally exposed population

    Czech Academy of Sciences Publication Activity Database

    Rössner ml., Pavel; Rössnerová, Andrea; Šrám, Radim

    2011-01-01

    Roč. 707, 1-2 (2011), s. 34-41 ISSN 0027-5107 R&D Projects: GA MŽP(CZ) SP/1B3/8/08 Institutional research plan: CEZ:AV0Z50390512 Keywords : air pollution * oxidative stress * chromosomal aberrations Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 2.850, year: 2011

  12. Chromosome aberrations and cell survival in irradiated mammalian cells

    International Nuclear Information System (INIS)

    Tremp, J.

    1981-01-01

    A possible correlation between chromosome aberrations and reduced proliferation capacity or cell death was investigated. Synchronized Chinese hamster fibroblast cells were irradiated with 300 rad of x rays in early G 1 . Despite synchronization the cells reached the subsequent mitosis at different times. The frequency of chromosome aberrations was determined in the postirradiation division at 2-h intervals. The highest frequency occurred in cells with a first cell cycle of medium length. The colony-forming ability of mitotic cells was measured in parallel samples by following the progress of individual mitoses. The proportion of cells forming macrocolonies decreased with increasing cell cycle length, and the number of non-colony-forming cells increased. Irrespective of various first cell cycle lengths and different frequencies of chromosome aberrations, the number of cells forming microcolonies remained constant. A correlation was found between the absence of chromosome aberrations and the ability of cells to form macrocolonies. However, cells with a long first cell cycle formed fewer macrocolonies than expected

  13. Teaching Politically Correct Language

    Science.gov (United States)

    Tsehelska, Maryna

    2006-01-01

    This article argues that teaching politically correct language to English learners provides them with important information and opportunities to be exposed to cultural issues. The author offers a brief review of how political correctness became an issue and how being politically correct influences the use of language. The article then presents…

  14. Chromatin structure and ionizing-radiation-induced chromosome aberrations

    International Nuclear Information System (INIS)

    Muehlmann-Diaz, M.C.

    1993-01-01

    The possible influence of chromatic structure or activity on chromosomal radiosensitivity was studied. A cell line was isolated which contained some 10 5 copies of an amplified plasmid in a single large mosquito artificial chromosome (MAC). This chromosome was hypersensitive to DNase I. Its radiosensitivity was some three fold greater than normal mosquito chromosomes in the same cell. In cultured human cells irradiated during G 0 , the initial breakage frequency in chromosome 4, 19 and the euchromatic and heterochromatic portions of the Y chromosome were measured over a wide range of doses by inducing Premature Chromosome Condensation (PCC) immediately after irradiation with Cs-137 gamma rays. No evidence was seen that Y heterochromatin or large fragments of it remained unbroken. The only significant deviation from the expected initial breakage frequency per Gy per unit length of chromosome was that observed for the euchromatic portion of the Y chromosome, with breakage nearly twice that expected. The development of aberrations involving X and Y chromosomes at the first mitosis after irradation was also studied. Normal female cells sustained about twice the frequency of aberrations involving X chromosomes for a dose of 7.3 Gy than the corresponding male cells. Fibroblasts from individuals with supernumerary X chromosomes did not show any further increase in X aberrations for this dos. The frequency of aberrations involving the heterochromatic portion of the long arm of the Y chromosome was about what would be expected for a similar length of autosome, but the euchromatic portion of the Y was about 3 times more radiosensitive per unit length. 5-Azacytidine treatment of cultured human female fibroblasts or fibroblasts from a 49,XXXXY individual, reduced the methylation of cytosine residues in DNA, and resulted in an increased chromosomal radiosensitivity in general, but it did not increase the frequency of aberrations involving the X chromosomes

  15. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Details are presented of a tomographic scanning apparatus, its rotational assembly, and the control and circuit elements, with particular reference to the amplifier and multiplexing circuits enabling detector signal calibration. (U.K.)

  16. Tomographic Scanning Imaging Seeker

    National Research Council Canada - National Science Library

    Hovland, Harald

    2005-01-01

    .... Simulation results are provided to show the reconstruction quality. The concept, using a single pixel and a simple rotating axis scan mechanism, allows for a simple, low-cost, software-driven imaging sensor...

  17. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... which are encased in metal and plastic and most often shaped like a box, attached to a ... will I experience during and after the procedure? Most thyroid scan and thyroid uptake procedures are painless. ...

  18. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Details are given of a tomographic scanning apparatus, with particular reference to a multiplexer slip ring means for receiving output from the detectors and enabling interfeed to the image reconstruction station. (U.K.)

  19. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information needed to make a diagnosis or to determine appropriate treatment, if any. Nuclear ...

  20. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... energy. top of page What are some common uses of the procedure? The thyroid scan is used ... the test. You should also drink plenty of water to help flush the radioactive material out of ...

  1. Thyroid Scan and Uptake

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    Full Text Available ... the body converts food to energy. top of page What are some common uses of the procedure? The ... type of scan you are undergoing. top of page What does the equipment look like? The special camera ...

  2. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... nuclear medicine procedures are able to pinpoint molecular activity within the body, they offer the potential to ... tells you otherwise, you may resume your normal activities after your nuclear medicine scan. If any special ...

  3. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... gamma camera heads are oriented at a 90 degree angle and placed over the patient's body. SPECT ... are scheduled for an additional procedure that same day that requires an intravenous line. Actual scanning time ...

  4. Thyroid Scan and Uptake

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    Full Text Available ... energy. top of page What are some common uses of the procedure? The thyroid scan is used ... computer aids in creating the images from the data obtained by the gamma camera. A probe is ...

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information ...

  6. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information needed to make a diagnosis or to determine appropriate treatment, if any. Nuclear medicine is less expensive and ...

  7. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    This patent specification relates to a tomographic scanning apparatus using a fan beam and digital output signal, and particularly to the design of the gas-pressurized ionization detection system. (U.K.)

  8. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... abnormal was found, and should not be a cause of concern for you. If you had an intravenous ... abnormal was found, and should not be a cause of concern for you. Actual scanning time for each ...

  9. The Scanning Optical Microscope.

    Science.gov (United States)

    Sheppard, C. J. R.

    1978-01-01

    Describes the principle of the scanning optical microscope and explains its advantages over the conventional microscope in the improvement of resolution and contrast, as well as the possibility of producing a picture from optical harmonies generated within the specimen.

  10. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... evaluate changes in the gland following medication use, surgery, radiotherapy or chemotherapy top of page How should ... such as an x-ray or CT scan, surgeries or treatments using iodinated contrast material within the ...

  11. Scanning Auger Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — A JEOL model 7830F field emission source, scanning Auger microscope.Specifications / Capabilities:Ultra-high vacuum (UHV), electron gun range from 0.1 kV to 25 kV,...

  12. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... liquid or capsule form, it is typically swallowed up to 24 hours before the scan. The radiotracer given by intravenous injection is usually given up to 30 minutes prior to the test. When ...

  13. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... exam of any medications you are taking, including vitamins and herbal supplements. You should also inform them ... of scan you are undergoing. top of page What does the equipment look like? The special camera ...

  14. Thyroid Scan and Uptake

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    Full Text Available ... Because nuclear medicine procedures are able to pinpoint molecular activity within the body, they offer the potential ... or imaging device that produces pictures and provides molecular information. The thyroid scan and thyroid uptake provide ...

  15. Thyroid Scan and Uptake

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    Full Text Available ... scan and thyroid uptake provide information about the structure and function of the thyroid. The thyroid is ... computer, create pictures offering details on both the structure and function of organs and tissues in your ...

  16. Thyroid Scan and Uptake

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    Full Text Available ... abnormal was found, and should not be a cause of concern for you. If you had an ... abnormal was found, and should not be a cause of concern for you. Actual scanning time for ...

  17. Pediatric CT Scans

    Science.gov (United States)

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  18. Lung gallium scan

    Science.gov (United States)

    ... produced by the gallium. Images display on a computer screen. During the scan, it is important that ... M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health ...

  19. Thyroid Scan and Uptake

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    Full Text Available ... of page What are some common uses of the procedure? The thyroid scan is used to determine ... you are undergoing. top of page What does the equipment look like? The special camera and imaging ...

  20. Thyroid Scan and Uptake

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    Full Text Available ... Uptake? A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) ... of thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that ...

  1. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... scan and uptake uses small amounts of radioactive materials called radiotracers, a special camera and a computer ... last two months that used iodine-based contrast material. Your doctor will instruct you on how to ...

  2. RBC nuclear scan

    Science.gov (United States)

    ... scan uses small amounts of radioactive material to mark (tag) red blood cells (RBCs). Your body is ... Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 135. Tavakkoli A, Ashley SW. Acute ...

  3. Cervical spine CT scan

    Science.gov (United States)

    ... your provider if you take the diabetes medicine metformin (Glucophage). You may need to take extra steps ... to contrast dye Birth defect if done during pregnancy CT scans expose you to more radiation than ...

  4. Leg CT scan

    Science.gov (United States)

    ... your provider if you take the diabetes medicine metformin (Glucophage). You may need to take extra steps ... to contrast dye Birth defect if done during pregnancy CT scans expose you to more radiation than ...

  5. Shoulder CT scan

    Science.gov (United States)

    ... your provider if you take the diabetes medicine metformin (Glucophage) because you may need to take extra ... to contrast dye Birth defect if done during pregnancy CT scans do expose you to more radiation ...

  6. Knee CT scan

    Science.gov (United States)

    ... your provider if you take the diabetes medicine metformin (Glucophage). You may need to take extra steps ... to contrast dye Birth defect if done during pregnancy CT scans give off more radiation than regular ...

  7. Arm CT scan

    Science.gov (United States)

    ... your provider if you take the diabetes drug metformin (Glucophage). You may need to take special steps ... to contrast dye Birth defect if done during pregnancy CT scans expose you to more radiation than ...

  8. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is ... thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that uses ...

  9. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Uptake? A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is ... of thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that uses ...

  10. Further progress for a fast scanning of nuclear emulsions with Large Angle Scanning System

    Science.gov (United States)

    Alexandrov, A.; Tioukov, V.; Vladymyrov, M.

    2014-02-01

    The LASSO (Large Angle Scanning System for OPERA) is a scanning system designed in the framework of the OPERA experiment as a result of several R&Ds aimed to improve the performance of the European Scanning System (ESS) by increasing the scanning speed, the angular acceptance and the efficiency in microtrack reconstruction. The novel Continuous Motion (CM) scanning approach allows to double the ESS nominal speed without any changes in the hardware set-up. The LASSO modular design makes the system easily adaptable to new hardware. The novel microtrack reconstruction algorithm has been developed to be efficient in both standard Stop&Go (SG) and CM modes, performing a number of corrections during the processing like corrections for vibrations, optical distortions, field of view curvature. As an intermediate step it reconstructs silver grains positions inside emulsion layer to make a transition from 2D images to real 3D traces of a charged particle. This allows the algorithm to have no internal limits on the slope of microtracks being equally efficient on all angles. The LASSO has been used for about one year for mass production scanning of emulsion films of OPERA, Muon Radiography and also of films employed to study nuclear fragmentation of ion beams used in medical physics. More than 50000 cm2 of the emulsion surface have been analyzed during this period.

  11. Analysis of Chromosomal Aberrations after Low and High Dose Rate Gamma Irradiation in ATM or NBS Suppressed Human Fibroblast Cells

    Science.gov (United States)

    Hada, M.; Huff, J. L.; Patel, Z.; Pluth, J. M.; George, K. A.; Cucinotta, F. A.

    2009-01-01

    A detailed understanding of the biological effects of heavy nuclei is needed for space radiation protection and for cancer therapy. High-LET radiation produces more complex DNA lesions that may be non-repairable or that may require additional processing steps compared to endogenous DSBs, increasing the possibility of misrepair. Interplay between radiation sensitivity, dose, and radiation quality has not been studied extensively. Previously we studied chromosome aberrations induced by low- and high- LET radiation in several cell lines deficient in ATM (ataxia telangactasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. We found that the yields of both simple and complex chromosomal aberrations were significantly increased in the DSB repair defective cells compared to normal cells. The increased aberrations observed for the ATM and NBS defective lines was due to a significantly larger quadratic dose-response term compared to normal fibroblasts for both simple and complex aberrations, while the linear dose-response term was significantly higher in NBS cells only for simple exchanges. These results point to the importance of the functions of ATM and NBS in chromatin modifications that function to facilitate correct DSB repair and minimize aberration formation. To further understand the sensitivity differences that were observed in ATM and NBS deficient cells, in this study, chromosomal aberration analysis was performed in normal lung fibroblast cells treated with KU-55933, a specific ATM kinase inhibitor, or Mirin, an MRN complex inhibitor involved in activation of ATM. We are also testing siRNA knockdown of these proteins. Normal and ATM or NBS suppressed cells were irradiated with gamma-rays and chromosomes were collected with a premature chromosome

  12. Optical quality for keratoconic eyes with conventional RGP lens and simulated, customised contact lens corrections: a comparison.

    Science.gov (United States)

    Jinabhai, Amit; Neil Charman, W; O'Donnell, Clare; Radhakrishnan, Hema

    2012-05-01

    To compare monochromatic aberrations of keratoconic eyes when uncorrected, corrected with spherically-powered RGP (rigid gas-permeable) contact lenses and corrected using simulations of customised soft contact lenses for different magnitudes of rotation (up to 15°) and translation (up to 1mm) from their ideal position. The ocular aberrations of examples of mild, moderate and severe keratoconic eyes were measured when uncorrected and when wearing their habitual RGP lenses. Residual aberrations and point-spread functions of each eye were simulated using an ideal, customised soft contact lens (designed to neutralise higher-order aberrations, HOA) were calculated as a function of the angle of rotation of the lens from its ideal orientation, and its horizontal and vertical translation. In agreement with the results of other authors, the RGP lenses markedly reduced both lower-order aberrations and HOA for all three patients. When compared with the RGP lens corrections, the customised lens simulations only provided optical improvements if their movements were constrained within limits which appear to be difficult to achieve with current technologies. At the present time, customised contact lens corrections appear likely to offer, at best, only minor optical improvements over RGP lenses for patients with keratoconus. If made in soft materials, however, these lenses may be preferred by patients in term of comfort. Ophthalmic & Physiological Optics © 2012 The College of Optometrists.

  13. Subjective face recognition difficulties, aberrant sensibility, sleeping disturbances and aberrant eating habits in families with Asperger syndrome

    Directory of Open Access Journals (Sweden)

    Källman Tiia

    2005-04-01

    Full Text Available Abstract Background The present study was undertaken in order to determine whether a set of clinical features, which are not included in the DSM-IV or ICD-10 for Asperger Syndrome (AS, are associated with AS in particular or whether they are merely a familial trait that is not related to the diagnosis. Methods Ten large families, a total of 138 persons, of whom 58 individuals fulfilled the diagnostic criteria for AS and another 56 did not to fulfill these criteria, were studied using a structured interview focusing on the possible presence of face recognition difficulties, aberrant sensibility and eating habits and sleeping disturbances. Results The prevalence for face recognition difficulties was 46.6% in individuals with AS compared with 10.7% in the control group. The corresponding figures for subjectively reported presence of aberrant sensibilities were 91.4% and 46.6%, for sleeping disturbances 48.3% and 23.2% and for aberrant eating habits 60.3% and 14.3%, respectively. Conclusion An aberrant processing of sensory information appears to be a common feature in AS. The impact of these and other clinical features that are not incorporated in the ICD-10 and DSM-IV on our understanding of AS may hitherto have been underestimated. These associated clinical traits may well be reflected by the behavioural characteristics of these individuals.

  14. Subjective face recognition difficulties, aberrant sensibility, sleeping disturbances and aberrant eating habits in families with Asperger syndrome

    Science.gov (United States)

    Nieminen-von Wendt, Taina; Paavonen, Juulia E; Ylisaukko-Oja, Tero; Sarenius, Susan; Källman, Tiia; Järvelä, Irma; von Wendt, Lennart

    2005-01-01

    Background The present study was undertaken in order to determine whether a set of clinical features, which are not included in the DSM-IV or ICD-10 for Asperger Syndrome (AS), are associated with AS in particular or whether they are merely a familial trait that is not related to the diagnosis. Methods Ten large families, a total of 138 persons, of whom 58 individuals fulfilled the diagnostic criteria for AS and another 56 did not to fulfill these criteria, were studied using a structured interview focusing on the possible presence of face recognition difficulties, aberrant sensibility and eating habits and sleeping disturbances. Results The prevalence for face recognition difficulties was 46.6% in individuals with AS compared with 10.7% in the control group. The corresponding figures for subjectively reported presence of aberrant sensibilities were 91.4% and 46.6%, for sleeping disturbances 48.3% and 23.2% and for aberrant eating habits 60.3% and 14.3%, respectively. Conclusion An aberrant processing of sensory information appears to be a common feature in AS. The impact of these and other clinical features that are not incorporated in the ICD-10 and DSM-IV on our understanding of AS may hitherto have been underestimated. These associated clinical traits may well be reflected by the behavioural characteristics of these individuals. PMID:15826308

  15. Corneal aberration changes after rigid gas permeable contact lens wear in keratokonic patients

    Directory of Open Access Journals (Sweden)

    Fereshteh Shokrollahzadeh

    2016-12-01

    Conclusion: In this study, corneal aberrations remained unchanged 3 months after wearing RGP contact lens. Further studies with sufficient samples in different groups of keratoconus severity or baseline aberrations are needed to obtain more accurate results.

  16. Chromosomal Aberrations in Monozygotic and Dizygotic Twins Versus Singletons in Denmark During 1968-2009

    DEFF Research Database (Denmark)

    Kristensen, Lone Krøldrup; Larsen, Lisbeth A; Fagerberg, Christina

    2017-01-01

    BACKGROUND: Hall (Embryologic development and monozygotic twinning. Acta Geneticae Medicae et Gemellologiae, Vol. 45, 1996, pp. 53-57) hypothesized that chromosomal aberrations can lead to monozygotic (MZ) twinning. However, twinning and chromosomal aberrations increase prenatal mortality and could...

  17. Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana

    NARCIS (Netherlands)

    Ji, X.

    2014-01-01

    Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana. I studied numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana. The large genomic changes are important for

  18. Correction of a Depth-Dependent Lateral Distortion in 3D Super-Resolution Imaging.

    Directory of Open Access Journals (Sweden)

    Lina Carlini

    Full Text Available Three-dimensional (3D localization-based super-resolution microscopy (SR requires correction of aberrations to accurately represent 3D structure. Here we show how a depth-dependent lateral shift in the apparent position of a fluorescent point source, which we term `wobble`, results in warped 3D SR images and provide a software tool to correct this distortion. This system-specific, lateral shift is typically > 80 nm across an axial range of ~ 1 μm. A theoretical analysis based on phase retrieval data from our microscope suggests that the wobble is caused by non-rotationally symmetric phase and amplitude aberrations in the microscope's pupil function. We then apply our correction to the bacterial cytoskeletal protein FtsZ in live bacteria and demonstrate that the corrected data more accurately represent the true shape of this vertically-oriented ring-like structure. We also include this correction method in a registration procedure for dual-color, 3D SR data and show that it improves target registration error (TRE at the axial limits over an imaging depth of 1 μm, yielding TRE values of < 20 nm. This work highlights the importance of correcting aberrations in 3D SR to achieve high fidelity between the measurements and the sample.

  19. Vacuum chamber eddy current correction coil for the AGS booster

    International Nuclear Information System (INIS)

    Danby, G.; Jackson, J.

    1988-01-01

    This paper reports on the AGS Booster injector that performs a variety of functions. Heavy ion acceleration requires a bakeable, ultra-high vacuum system (VC). Acceleration for intense proton beams requires rapid cycling (B ≤10T/sec). If straight forward heavy walled VC are used, the field perturbations due to eddy currents are large. The state of the art lattice has highly distributed lumped sextupoles capable of substantially correcting the induced field nonlinearity. Nevertheless, for the very highest space charge-intensity limits, it is desirable to have the capability to remove eddy current fields at the source. Correction coils attached to the outside of the VC cancel its current aberrations over the required good field aperture. These can be passively powered by transformer action, using two turn windings around the magnet yoke. Programmed power supplies can also be used. This inexpensive additional correction option uses a three turn per quadrant coil which follows the local contour of the VC. Transverse movements of several mms of the VC will have no beam optical effect since the large field aberrations and their corrections have the same displace coordinates. Experimental and computer studies will be presented, as well as mechanical and electrical design of a simple method of construction

  20. Vacuum chamber eddy current correction coil for the AGS Booster

    International Nuclear Information System (INIS)

    Danby, G.; Jackson, J.

    1988-01-01

    The AGS Booster injector will perform a variety of functions. Heavy ion acceleration requires a bakeable, ultra-high vacuum system (VC). Acceleration for intense proton beams requires rapid cycling (B /preceq/ 10T/sec). If straight forward heavy walled VC are used, the field perturbations due to eddy currents are large. The state of the art lattice has highly distributed lumped sextupoles capable of substantially correcting the induced field nonlinearity. Nevertheless, for the very highest space charge-intensity limits, it is desirable to have the capability to remove eddy current fields at the source. Correction coils attached to the outside of the VC cancel its current aberrations over the required good field aperture. These can be passively powered by transformer action, using two turn windings around the magnet yoke. Programmed power supplies can also be used. This inexpensive additional correction option uses a three turn per quadrant coil which follows the local contour of the VC. Transverse movements of several mms of the VC will have no beam optical effect since the large field aberrations and their corrections have the same displaced coordinates. Experimental and computer studies will be presented, as well as mechanical and electrical design of a simple method of construction. 6 figs

  1. Facial recognition and laser surface scan: a pilot study

    DEFF Research Database (Denmark)

    Lynnerup, Niels; Clausen, Maja-Lisa; Kristoffersen, Agnethe May

    2009-01-01

    that the discriminatory value was 86.7%. We also tested the surface scanner in terms of reliability in establishing point measures on skulls, and compared with physical measurements performed by calipers. The variation was on average 1 mm for five cranial measures. We suggest how surface scanning might be applied...... software (MIMICS and Photoshop) the surface scans were matched with the photographs in blind trials. The matches were graded as: a good fit; possible fit; and no fit. All the surface scans and photos were matched correctly, although one surface scan could be matched with two angled photographs, meaning...

  2. CT-based attenuation and scatter correction compared with uniform attenuation correction in brain perfusion SPECT imaging for dementia

    Science.gov (United States)

    Gillen, Rebecca; Firbank, Michael J.; Lloyd, Jim; O'Brien, John T.

    2015-09-01

    This study investigated if the appearance and diagnostic accuracy of HMPAO brain perfusion SPECT images could be improved by using CT-based attenuation and scatter correction compared with the uniform attenuation correction method. A cohort of subjects who were clinically categorized as Alzheimer’s Disease (n=38 ), Dementia with Lewy Bodies (n=29 ) or healthy normal controls (n=30 ), underwent SPECT imaging with Tc-99m HMPAO and a separate CT scan. The SPECT images were processed using: (a) correction map derived from the subject’s CT scan or (b) the Chang uniform approximation for correction or (c) no attenuation correction. Images were visually inspected. The ratios between key regions of interest known to be affected or spared in each condition were calculated for each correction method, and the differences between these ratios were evaluated. The images produced using the different corrections were noted to be visually different. However, ROI analysis found similar statistically significant differences between control and dementia groups and between AD and DLB groups regardless of the correction map used. We did not identify an improvement in diagnostic accuracy in images which were corrected using CT-based attenuation and scatter correction, compared with those corrected using a uniform correction map.

  3. The effect of aberrated recording beams on reflecting Bragg gratings

    Science.gov (United States)

    SeGall, Marc; Ott, Daniel; Divliansky, Ivan; Glebov, Leonid B.

    2013-03-01

    The effect of aberrations present in the recording beams of a holographic setup is discussed regarding the period and spectral response of a reflecting volume Bragg grating. Imperfect recording beams result in spatially varying resonant wavelengths and the side lobes of the spectrum are washed out. Asymmetrical spectra, spectral broadening, and a reduction in peak diffraction efficiency may also be present, though these effects are less significant for gratings with wider spectral widths. Reflecting Bragg gratings (RBGs) are used as elements in a variety of applications including spectral beam combining1,2, mode locking3,4, longitudinal and transverse mode selection in lasers5,6, and sensing7,8. For applications requiring narrow spectral selectivity9, or large apertures10, these gratings must have a uniform period throughout the length of the recording medium, which may be on the order of millimeters. However, when using typical recording techniques such as two-beam interference for large aperture gratings and phase-mask recording of fiber gratings, aberrations from the optical elements in the system result in an imperfect grating structure11-13. In this paper we consider the effects of aberrations on large aperture gratings recorded in thick media using the two-beam interference technique. Previous works in analyzing the effects of aberrations have considered the effects of aberrations in a single recording plane where the beams perfectly overlap. Such an approach is valid for thin media (on the order of tens of microns), but for thick recording media (on the order of several millimeters) there will be a significant shift in the positions of the beams relative to each other as they traverse the recording medium. Therefore, the fringe pattern produced will not be constant throughout the grating if one or both beams have a non-uniform wavefront. Such non-uniform gratings may have a wider spectral width, a shifted resonant wavelength, or other problems. It is

  4. Adaptive optics scanning laser ophthalmoscopy in combination with en-face optical coherence tomography

    International Nuclear Information System (INIS)

    Felberer, F.

    2014-01-01

    The human retina is a most important tissue and plays a fundamental role for the vision. Diseases of the eye affect the normal retinal function which, if untreated, may lead to vision loss or ultimately to blindness. Thus, in vivo diagnostic tools that provide detailed information on the retinal status are required in order to improve diagnosis and treatment. In recent years, several new optical imaging methods of the human retina have been developed and now represent the key part in a standard ophthalmic examination process. One of these technologies is optical coherence tomography (OCT), which provides images of the retina noninvasively and with a high axial resolution. However, imperfections of the eye's optics cause aberrations of the wavefront of the imaging light, thus limiting the transverse resolution of such systems. Improvements in the resolution of retinal images are necessary to resolve individual cells (e.g. photoreceptors) which may provide new opportunities in retinal diagnostics and therapy control. Adaptive optics (AO), a technology known from astronomy, may be used to increase image resolution. Aberrations of the imaging light are measured and corrected, resulting in an increase of lateral resolution up to the diffraction limit. Within this thesis, AO was combined with a scanning laser ophthalmoscope (SLO) that enables high resolution imaging of the retina. Measurements on healthy subjects demonstrated the ability of the system to resolve foveal cones (the smallest cone photoreceptors within the retina) and even rod photoreceptors. However, the depth resolution of the system remained limited compared to OCT instruments. Thus, in a second step, the instrument was extended to a combined AO-SLO/OCT system. The OCT system is based on transversal scanning (TS)-OCT which records en-face images of the retina and incorporates a high-speed axial eye tracking device. Together with transverse motion correction based on the AO-SLO images, the system

  5. Nodular Hyperplasia Arising from the Lateral Aberrant Thyroid Tissue: A Case Report

    International Nuclear Information System (INIS)

    Jeong, Min Hye; Park, Jeong Seon; Lee, Young Jun

    2012-01-01

    The presence of aberrant thyroid tissue in the lateral neck is very rare. In addition, nodular hyperplasia in ectopic thyroid has rarely been reported. Due to the unusual location, the presence of lateral aberrant thyroid tissue could be misdiagnosed as a lymphadenopathy, neurogenic tumor, etc. We report on a case of nodular hyperplasia arising from the right lateral aberrant thyroid tissue.

  6. Environmental transmission electron microscopy for catalyst materials using a spherical aberration corrector

    International Nuclear Information System (INIS)

    Takeda, Seiji; Kuwauchi, Yasufumi; Yoshida, Hideto

    2015-01-01

    Atomic resolution has been obtained using environmental transmission electron microscopy (ETEM) by installing a spherical aberration corrector (Cs-corrector) on the objective lens. Simultaneously, the technology for controlling the environment around a specimen in ETEM has advanced significantly in the past decade. Quantification methodology has recently been established for deriving relevant experimental data in catalyst materials from substantial and systematic ETEM observation at the atomic scale. With this background, this paper summarizes aspects of the evolutional microscopy technique: necessary conditions for atomic resolution in ETEM; reduction of the scattering of electrons by the medium surrounding a specimen; and an environmental cell for structural imaging of a crystalline specimen. The high spatial resolution of a Cs-corrected ETEM is demonstrated for different observation conditions. After statistical analysis combined with numerical image analysis of ETEM data is briefly described, the recent applications of the Cs-corrected ETEM to catalyst materials are reviewed. For gold nanoparticulate catalysts, the structural information on the reaction sites and adsorption sites are deduced. For Pt nanoparticulate catalysts, ETEM studies elucidate the correlation between the catalytic activity and the morphology of the nanoparticles. These studies also reveal oxidation and reduction on the topmost Pt surface layer at the atomic scale. Finally, current issues and the future perspectives of Cs-corrected ETEM are summarized, including the reproducibility of ETEM observation data, the control of environments, the critical evaluation of electron irradiation effects, the full implementation of transmission electron microscopy technology in ETEM, and the safety issues for an ETEM laboratory. - Highlights: • Advancement of Cs corrected environmental transmission electron microscopy. • Structural determination of catalyst materials in reaction environments.

  7. Analysis of corneal high order aberrations in eyes with subclinical keratoconus

    Directory of Open Access Journals (Sweden)

    Dai-Jin Ma

    2013-09-01

    Full Text Available AIM: To analyze the higher-order aberrations of anterior corneal surface in patients with subclinical keratoconus.METHODS: Forty-three eyes with the diagnosis of subclinical keratoconus(KCS group, mean age 25.32±4.18 yearsand 60 normal eyes(control group, mean age 24.63±4.82 yearswere included in this study. Corneal higher-order aberrations in each eye were measured by OPD Scan ARK-10000. Root mean square(RMSvalues were calculated for total higher-order aberrations(HOAs, total coma(TC, total trefoil(TTand total spherical aberration(TSin 3mm and 6mm central area. The aberrometric parameters were respectively compared between two groups by Student's t-test.RESULTS: In 3mm central area, the RMS of corneal HOAs, TC, TT and TS were 0.424±0.175μm, 0.113±0.068μm, 0.262±0.132μm, 0.016±0.010μm respectively in KCS group, while those in control group were 0.310±0.093μm, 0.070±0.038μm, 0.244±0.106μm, 0.019±0.016μm respectively, the differences were statistically significant in HOAs and TC(t=3.896, 3.748; P=0.000, 0.000, except for TT and TS(t=0.740, 1.169; P=0.231, 0.124. In 6mm central area, the RMS of corneal HOAs, TC, TT and TS were 0.987±0.292μm, 0.642±0.260μm, 0.487±0.208μm, 0.292±0.145μm respectively in KCS group, while that in control group were 0.587±0.146μm, 0.252±0.113μm, 0.337±0.182μm, 0.271±0.065μm respectively, the differences were statistically significant in HOAs, TC and TT(t=8.273, 9.231, 3.800; P=0.000, 0.000, 0.000, except for TS(t=0.888, P=0.191.CONCLUSION: The corneal higher-order aberration, especially TC, is significantly higher in subclinical keratoconic eyes than in normal eyes. It may be a potential diagnostic tool for subclinical keratoconus.

  8. Radiation scanning system

    International Nuclear Information System (INIS)

    1979-01-01

    In the radiation scanning system the radiation emitted from an image field is scanned by a field of radiosensitive detector elements, and the signals transmitted are used to control the video input of a scanning-pattern image display unit. By the variations of the transmitting properties of the detector elements and the electronic equipment spurious patterns are produced on the projected picture. In order to prevent this there is provided for a compensating circuit and a comparator by means of which the variations of the transmitting properties are compensated. It works synchronous by together with a multipler device and carries out a measurement of the statistic moment of the voltage of each channel. The compensating device may be designed as an open or closed control loop. (orig.) [de

  9. Frequency scanning microstrip antennas

    DEFF Research Database (Denmark)

    Danielsen, Magnus; Jørgensen, Rolf

    1979-01-01

    The principles of using radiating microstrip resonators as elements in a frequency scanning antenna array are described. The resonators are cascade-coupled. This gives a scan of the main lobe due to the phase-shift in the resonator in addition to that created by the transmission line phase......-shift. Experimental results inX-band, in good agreement with the theory, show that it is possible to scan the main lobe an angle ofpm30degby a variation of the frequencypm300MHz, and where the 3 dB beamwidth is less than10deg. The directivity was 14.7 dB, while the gain was 8.1 dB. The efficiency might be improved...

  10. Research on reflective optical telescope system's wavefront aberration compensation method

    Science.gov (United States)

    Duan, Xueting

    Wavefront aberration measurement of the image quality of reflective telescope system which has a large aperture and long focal length is one of the frequently-used methods of high-precision test and alignment. It was widely used during the large aperture telescope manufacturing process. The influences of surface shape error of the reflective optical telescope system components were simulated and analyst by input the actual measuring data into the optical design software CODE V in this article. According to the test results compared to the alignment process, the accuracy of the simulation method was indicated. At the same time, the wavefront aberration optical compensation principle of the reflective optical telescope system was proved by the simulation of alignment. And in this article, the feasibility of the application of optical phase compensation alignment method was investigated.

  11. Complex Pupil Masks for Aberrated Imaging of Closely Spaced Objects

    Science.gov (United States)

    Reddy, A. N. K.; Sagar, D. K.; Khonina, S. N.

    2017-12-01

    Current approach demonstrates the suppression of optical side-lobes and the contraction of the main lobe in the composite image of two object points of the optical system under the influence of defocusing effect when an asymmetric phase edges are imposed over the apodized circular aperture. The resolution of two point sources having different intensity ratio is discussed in terms of the modified Sparrow criterion, functions of the degree of coherence of the illumination, the intensity difference and the degree of asymmetric phase masking. Here we have introduced and explored the effects of focus aberration (defect-of-focus) on the two-point resolution of the optical systems. Results on the aberrated composite image of closely spaced objects with amplitude mask and asymmetric phase masks forms a significant contribution in astronomical and microscopic observations.

  12. Retrospective chromosome aberration analysis of former uranium miners

    International Nuclear Information System (INIS)

    Meszaros, G.; Bognar, G.; Koeteles, G. J.

    2003-01-01

    In this paper we present our data collected in the period of 1981-1985 on 165 persons exposed by different radon concentrations expressed in working level month (WLM) units from 100 up to 600. Following the decommissioning of the uranium mine in Hungary in 1997 cytogenetic status of 131 persons were within a follow-up-study of their health conditions initiated by the Hungarian Academy of Science. The persons have terminated their underground activities 5 to 20 years before testing. The comparison of the two datasets suggest a long-term persistence of cytogenetic alterations above the population average values in large percentages of persons investigated. The frequency of chromosome aberrations of uranium miners was found increased in function of their exposure to radon. The comparison of the miner's categories 20 years ago and in the recent years demonstrated the long-term existence of aberrations for many years after completion of underground mining activities. (authors)

  13. Aberrations and adaptive optics in super-resolution microscopy

    Science.gov (United States)

    Booth, Martin; Andrade, Débora; Burke, Daniel; Patton, Brian; Zurauskas, Mantas

    2015-01-01

    As one of the most powerful tools in the biological investigation of cellular structures and dynamic processes, fluorescence microscopy has undergone extraordinary developments in the past decades. The advent of super-resolution techniques has enabled fluorescence microscopy – or rather nanoscopy – to achieve nanoscale resolution in living specimens and unravelled the interior of cells with unprecedented detail. The methods employed in this expanding field of microscopy, however, are especially prone to the detrimental effects of optical aberrations. In this review, we discuss how super-resolution microscopy techniques based upon single-molecule switching, stimulated emission depletion and structured illumination each suffer from aberrations in different ways that are dependent upon intrinsic technical aspects. We discuss the use of adaptive optics as an effective means to overcome this problem. PMID:26124194

  14. Chromosomal Aberrations in Humans Induced by Urban Air Pollution

    DEFF Research Database (Denmark)

    Knudsen, Lisbeth E.; Norppa, Hannu; Gamborg, Michael O.

    1999-01-01

    We have studied the influence of individual susceptibility factors on the genotoxic effects of urban air pollution in 106 nonsmoking bus drivers and 101 postal workers in the Copenhagen metropolitan area. We used the frequency of chromosomal aberrations in peripheral blood lymphocytes......, which was observed only in the bus drivers, appears to be associated with air pollution, whereas the NAT2 genotype effect, which affected all subjects, may influence the individual response to some other common exposure or the baseline level of chromosomal aberrations....... as a biomarker of genotoxic damage and dimethylsulfate-induced unscheduled DNA synthesis in mononuclear WBCs, the glutathione S-transferase M1 (GSTM1) genotype, and the N-acetyltransferase 2 (NAT2) genotype as biomarkers of susceptibility. The bus drivers, who had previously been observed to have elevated levels...

  15. Chromosomal aberrations and micronuclei frequencies in Bulgarian control population

    International Nuclear Information System (INIS)

    Popova, I.; Hadjidekova, V.; Hristova, R.; Atanasova, P.

    2004-01-01

    The aim of this investigation is to represent the frequency of spontaneous chromosomal damages in peripheral blood lymphocytes of Bulgarian control population. Material and methods: The investigated group includes persons belonging to both sexes and different ages. Each of them is interviewed of their social and health status. Sixteen persons are examined using the chromosomal aberrations analysis and forty-five with micronucleus test. The frequency of chromosomal aberrations varied between 0 - 2.4 % and the mean value is 1.00 %. The frequency of cells with micronuclei varied between 4.5 - 24.5 % and the mean value 12,9 %. Further work on the investigation of spontaneous frequency of chromosomal damages is in progress. (authors)

  16. Chromosome Aberrations in Human Lymphocytes Irradiated with Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin Hong; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The purpose of the present experiment was to provide data on the dose-dependent production of chromosome aberrations such as dicentrics, centric rings, and excess acentrics. Radiation is one of the more dangerous clastogens in the environment. Ionizing radiation causes chromosome breakages and various cytogenetic aberrations in exposed cells. In an investigation into radiation emergencies, it is important to estimate the dose to exposed persons for several reasons. Physical dosimeters (e. g., film badges) may misrepresent the actual radiation dose and may not be available in a radiological accident or terrorism incident. Biological dosimetry is suitable for estimating the radiation dose during such accidents. The dicentric chromosome assay is very sensitive and a reliable bio-indicator in cases of accidental overexposure.

  17. Aberrations and adaptive optics in super-resolution microscopy.

    Science.gov (United States)

    Booth, Martin; Andrade, Débora; Burke, Daniel; Patton, Brian; Zurauskas, Mantas

    2015-08-01

    As one of the most powerful tools in the biological investigation of cellular structures and dynamic processes, fluorescence microscopy has undergone extraordinary developments in the past decades. The advent of super-resolution techniques has enabled fluorescence microscopy - or rather nanoscopy - to achieve nanoscale resolution in living specimens and unravelled the interior of cells with unprecedented detail. The methods employed in this expanding field of microscopy, however, are especially prone to the detrimental effects of optical aberrations. In this review, we discuss how super-resolution microscopy techniques based upon single-molecule switching, stimulated emission depletion and structured illumination each suffer from aberrations in different ways that are dependent upon intrinsic technical aspects. We discuss the use of adaptive optics as an effective means to overcome this problem. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy.

  18. Attenuation correction for small animal PET tomographs

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Patrick L [David Geffen School of Medicine at UCLA, Crump Institute for Molecular Imaging, University of California, 700 Westwood Plaza, Los Angeles, CA 90095 (United States); Rannou, Fernando R [Departamento de Ingenieria Informatica, Universidad de Santiago de Chile (USACH), Av. Ecuador 3659, Santiago (Chile); Chatziioannou, Arion F [David Geffen School of Medicine at UCLA, Crump Institute for Molecular Imaging, University of California, 700 Westwood Plaza, Los Angeles, CA 90095 (United States)

    2005-04-21

    Attenuation correction is one of the important corrections required for quantitative positron emission tomography (PET). This work will compare the quantitative accuracy of attenuation correction using a simple global scale factor with traditional transmission-based methods acquired either with a small animal PET or a small animal x-ray computed tomography (CT) scanner. Two phantoms (one mouse-sized and one rat-sized) and two animal subjects (one mouse and one rat) were scanned in CTI Concorde Microsystem's microPET (registered) Focus{sup TM} for emission and transmission data and in ImTek's MicroCAT{sup TM} II for transmission data. PET emission image values were calibrated against a scintillation well counter. Results indicate that the scale factor method of attenuation correction places the average measured activity concentration about the expected value, without correcting for the cupping artefact from attenuation. Noise analysis in the phantom studies with the PET-based method shows that noise in the transmission data increases the noise in the corrected emission data. The CT-based method was accurate and delivered low-noise images suitable for both PET data correction and PET tracer localization.

  19. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    Abele, M.

    1983-01-01

    A computerized tomographic scanning apparatus suitable for diagnosis and for improving target identification in stereotactic neurosurgery is described. It consists of a base, a source of penetrating energy, a detector which produces scanning signals and detector positioning means. A frame with top and bottom arms secures the detector and source to the top and bottom arms respectively. A drive mechanism rotates the frame about an axis along which the frame may also be moved. Finally, the detector may be moved relative to the bottom arm in a direction contrary to the rotation of the frame. (U.K.)

  20. Calibration of scanning Lidar

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Courtney, Michael

    This report describes the tests carried out on a scanning lidar at the DTU Test Station for large wind turbines, Høvsøre. The tests were divided in two parts. In the first part, the purpose was to obtain wind speed calibrations at two heights against two cup anemometers mounted on a mast. Additio......This report describes the tests carried out on a scanning lidar at the DTU Test Station for large wind turbines, Høvsøre. The tests were divided in two parts. In the first part, the purpose was to obtain wind speed calibrations at two heights against two cup anemometers mounted on a mast...

  1. Scanning the phenomenological MSSM

    CERN Document Server

    Wuerzinger, Jonas

    2017-01-01

    A framework to perform scans in the 19-dimensional phenomenological MSSM is developed and used to re-evaluate the ATLAS experiments' sensitivity to R-parity-conserving supersymmetry with LHC Run 2 data ($\\sqrt{s}=13$ TeV), using results from 14 separate ATLAS searches. We perform a $\\tilde{t}_1$ dedicated scan, only considering models with $m_{\\tilde{t}_1}<1$ TeV, while allowing both a neutralino ($\\tilde{\\chi}_1^0$) and a sneutrino ($\\tilde{\

  2. Adaptive Optical Scanning Holography

    Science.gov (United States)

    Tsang, P. W. M.; Poon, Ting-Chung; Liu, J.-P.

    2016-01-01

    Optical Scanning Holography (OSH) is a powerful technique that employs a single-pixel sensor and a row-by-row scanning mechanism to capture the hologram of a wide-view, three-dimensional object. However, the time required to acquire a hologram with OSH is rather lengthy. In this paper, we propose an enhanced framework, which is referred to as Adaptive OSH (AOSH), to shorten the holographic recording process. We have demonstrated that the AOSH method is capable of decreasing the acquisition time by up to an order of magnitude, while preserving the content of the hologram favorably. PMID:26916866

  3. Aberrant infestation of goat mandibles with Oestrus ovis larvae.

    Science.gov (United States)

    Godara, R; Sharma, R L; Sharma, C S

    2010-01-01

    Nasal oestrosis is primarily an infestation of sheep. However, a non descript goat, aged three years was presented in lateral recumbency with clinical history of sneezing fits, laboured breathing, eroded mandibular lesions and bilaterally housing nasal bots therein. The first ever occurrence of nasal bots in an aberrant location (mandibles) in a goat, its therapeutic management and public health significance have been documented and discussed.

  4. Anatomically Correct Surface Recovery

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Nielsen, Jannik Boll; Larsen, Rasmus

    2015-01-01

    using the learned statistics. A quantitative evaluation is performed on a data set of 10 laser scans of ear canal impressions with minimal noise and artificial holes. We also present a qualitative evaluation on authentic partial scans from an actual direct in ear scanner prototype. Compared to a state...

  5. Analysis of chromosome aberration data by hybrid-scale models

    International Nuclear Information System (INIS)

    Indrawati, Iwiq; Kumazawa, Shigeru

    2000-02-01

    This paper presents a new methodology for analyzing data of chromosome aberrations, which is useful to understand the characteristics of dose-response relationships and to construct the calibration curves for the biological dosimetry. The hybrid scale of linear and logarithmic scales brings a particular plotting paper, where the normal section paper, two types of semi-log papers and the log-log paper are continuously connected. The hybrid-hybrid plotting paper may contain nine kinds of linear relationships, and these are conveniently called hybrid scale models. One can systematically select the best-fit model among the nine models by among the conditions for a straight line of data points. A biological interpretation is possible with some hybrid-scale models. In this report, the hybrid scale models were applied to separately reported data on chromosome aberrations in human lymphocytes as well as on chromosome breaks in Tradescantia. The results proved that the proposed models fit the data better than the linear-quadratic model, despite the demerit of the increased number of model parameters. We showed that the hybrid-hybrid model (both variables of dose and response using the hybrid scale) provides the best-fit straight lines to be used as the reliable and readable calibration curves of chromosome aberrations. (author)

  6. Pancreatic cancer genomes reveal aberrations in axon guidance pathway genes.

    Science.gov (United States)

    Biankin, Andrew V; Waddell, Nicola; Kassahn, Karin S; Gingras, Marie-Claude; Muthuswamy, Lakshmi B; Johns, Amber L; Miller, David K; Wilson, Peter J; Patch, Ann-Marie; Wu, Jianmin; Chang, David K; Cowley, Mark J; Gardiner, Brooke B; Song, Sarah; Harliwong, Ivon; Idrisoglu, Senel; Nourse, Craig; Nourbakhsh, Ehsan; Manning, Suzanne; Wani, Shivangi; Gongora, Milena; Pajic, Marina; Scarlett, Christopher J; Gill, Anthony J; Pinho, Andreia V; Rooman, Ilse; Anderson, Matthew; Holmes, Oliver; Leonard, Conrad; Taylor, Darrin; Wood, Scott; Xu, Qinying; Nones, Katia; Fink, J Lynn; Christ, Angelika; Bruxner, Tim; Cloonan, Nicole; Kolle, Gabriel; Newell, Felicity; Pinese, Mark; Mead, R Scott; Humphris, Jeremy L; Kaplan, Warren; Jones, Marc D; Colvin, Emily K; Nagrial, Adnan M; Humphrey, Emily S; Chou, Angela; Chin, Venessa T; Chantrill, Lorraine A; Mawson, Amanda; Samra, Jaswinder S; Kench, James G; Lovell, Jessica A; Daly, Roger J; Merrett, Neil D; Toon, Christopher; Epari, Krishna; Nguyen, Nam Q; Barbour, Andrew; Zeps, Nikolajs; Kakkar, Nipun; Zhao, Fengmei; Wu, Yuan Qing; Wang, Min; Muzny, Donna M; Fisher, William E; Brunicardi, F Charles; Hodges, Sally E; Reid, Jeffrey G; Drummond, Jennifer; Chang, Kyle; Han, Yi; Lewis, Lora R; Dinh, Huyen; Buhay, Christian J; Beck, Timothy; Timms, Lee; Sam, Michelle; Begley, Kimberly; Brown, Andrew; Pai, Deepa; Panchal, Ami; Buchner, Nicholas; De Borja, Richard; Denroche, Robert E; Yung, Christina K; Serra, Stefano; Onetto, Nicole; Mukhopadhyay, Debabrata; Tsao, Ming-Sound; Shaw, Patricia A; Petersen, Gloria M; Gallinger, Steven; Hruban, Ralph H; Maitra, Anirban; Iacobuzio-Donahue, Christine A; Schulick, Richard D; Wolfgang, Christopher L; Morgan, Richard A; Lawlor, Rita T; Capelli, Paola; Corbo, Vincenzo; Scardoni, Maria; Tortora, Giampaolo; Tempero, Margaret A; Mann, Karen M; Jenkins, Nancy A; Perez-Mancera, Pedro A; Adams, David J; Largaespada, David A; Wessels, Lodewyk F A; Rust, Alistair G; Stein, Lincoln D; Tuveson, David A; Copeland, Neal G; Musgrove, Elizabeth A; Scarpa, Aldo; Eshleman, James R; Hudson, Thomas J; Sutherland, Robert L; Wheeler, David A; Pearson, John V; McPherson, John D; Gibbs, Richard A; Grimmond, Sean M

    2012-11-15

    Pancreatic cancer is a highly lethal malignancy with few effective therapies. We performed exome sequencing and copy number analysis to define genomic aberrations in a prospectively accrued clinical cohort (n = 142) of early (stage I and II) sporadic pancreatic ductal adenocarcinoma. Detailed analysis of 99 informative tumours identified substantial heterogeneity with 2,016 non-silent mutations and 1,628 copy-number variations. We define 16 significantly mutated genes, reaffirming known mutations (KRAS, TP53, CDKN2A, SMAD4, MLL3, TGFBR2, ARID1A and SF3B1), and uncover novel mutated genes including additional genes involved in chromatin modification (EPC1 and ARID2), DNA damage repair (ATM) and other mechanisms (ZIM2, MAP2K4, NALCN, SLC16A4 and MAGEA6). Integrative analysis with in vitro functional data and animal models provided supportive evidence for potential roles for these genetic aberrations in carcinogenesis. Pathway-based analysis of recurrently mutated genes recapitulated clustering in core signalling pathways in pancreatic ductal adenocarcinoma, and identified new mutated genes in each pathway. We also identified frequent and diverse somatic aberrations in genes described traditionally as embryonic regulators of axon guidance, particularly SLIT/ROBO signalling, which was also evident in murine Sleeping Beauty transposon-mediated somatic mutagenesis models of pancreatic cancer, providing further supportive evidence for the potential involvement of axon guidance genes in pancreatic carcinogenesis.

  7. Chromosome aberrations in ataxia telangiectasia cells exposed to heavy ions

    Science.gov (United States)

    Kawata, T.; Cucinotta, F.; George, K.; Wu, H.; Shigematsu, N.; Furusawa, Y.; Uno, T.; Isobe, K.; Ito, H.

    Understanding of biological effects of heavy ions is important to assess healt h risk in space. One of the most important issues may be to take into account individual susceptibility. Ataxia telangiectasia (A-T) cells are known to exhibit abnormal responses to radiations but the mechanism of hyper radiosensitivity of A-T still remains unknown. We report chromosome aberrations in normal human fibroblasts and AT fibroblasts exposed to low- and high-LET radiations. A chemical-induced premature chromosome condensation (PCC) technique combined with chromosome- painting technique was applied to score chromosome aberrations in G2/M-phase cells. Following gamma irradiation, GM02052 cells were approximately 5 times more sensitive to g-rays than AG1522 cells. GM02052 cells had a much higher frequency of deletions and misrejoining than AG1522 cells. When the frequency of complex type aberrations was compared, GM02052 cells showed more than 10 times higher frequency than AG1522 cells. The results will be compared with those obtained from high-LET irradiations.

  8. Simple numerical chromosome aberrations in two pituitary adenomas

    DEFF Research Database (Denmark)

    Dietrich, C U; Pandis, N; Bjerre, P

    1993-01-01

    Cytogenetic analysis of short-term cultures of one non-secreting and one prolactin-producing pituitary adenoma revealed simple clonal numerical abnormalities in both tumors. The karyotype of the non-secreting adenoma was 48,XX, +4, +9[42]/49,XX, +4, +9, +20[2]/46,XX[6]. In the prolactin-secreting...... chromosomal anomaly.......-secreting adenoma, three aberrant clones were detected, giving the karyotype 45,X, -Y[20]/47,XY, +Y[6]/45,XY, -21[3]/46,XY[21]. One cell had the chromosome complement 46,X, -Y, +9; no other nonclonal aberrations were detected. The only hitherto published case of pituitary adenoma analyzed by banding techniques (Rey...... et al. [1986]: Cancer Genet Cytogenet 23:171-174) also had only numerical clonal changes that included extra copies of chromosome 9. We conclude that pituitary adenomas may be karyotypically characterized by numerical aberrations and that trisomy 9 seems to be the best candidate for a primary...

  9. Induction of chromosomal aberrations by neutron capture reactions

    International Nuclear Information System (INIS)

    Ikushima, Takaji

    1993-01-01

    Boron neutron capture reaction (B-NCR) has been practiced in the treatment of malignancies of the central nervous system and melanoma using a thermal neutron beam from the KUR. Because of the very large neutron absorption cross-section and high kinetic energy released, gadolinium (Gd-157) has been expected to be an another promising element for neutron capture therapy. The dose-response relationship was determined for the induction of chromosomal aberrations by neutron capture reactions by B-10 and Gd-157 in cultured mammalian cells. The cells were exposed to thermal neutron beam with and without B-10 enriched (97 atom %) boric acid or Gd-DTPA, and chromosome-type aberrations were analysed in the first metaphases following irradiation. The frequency of dicentrics and rings increased linearly with neutron fluence either in the presence or absence of B-10 boric acid, while the yield of chromosomal aberrations induced by Gd-NCR increased in a linear quadratic fashion as a function of dose as in γ-rayed cells. Survival curves for the cells exposed to thermal neutrons showed no shoulder irrespective of the loading of B-10, but Gd-NCR produced the survival curve with a small shoulder. The differential chromosomal response to B-NCR and Gd-NCR might reflect the difference in radiation quality generated from the two types of thermal neutron capture reaction. (J.P.N.)

  10. Aberrant behavior and cognitive ability in preschool children

    Directory of Open Access Journals (Sweden)

    Bala Gustav

    2007-01-01

    Full Text Available The sample included 712 preschool boys and girls at the age of 4 to 7 years (mean 5.96 decimal years and standard deviation .96 from preschool institutions in Novi Sad, Sombor, Sremska Mitrovica and Bačka Palanka. Information concerning 36 indicators of aberrant behavior of the children were supplied by their parents, whereas their cognitive ability was tested by Raven’s progressive colored matrices. Based on factor analysis (promax method, four factors i.e. generators of aberrant behavior in children were singled out: aggression, anxiousness, dissociation, and hysteria, whose relations with cognitive functioning and age were also analyzed by factor analysis. Aberrant behavior and cognitive abilities show significant interrelatedness. Owing to orderly developed cognitive abilities, a child understands essence and reality of problems, realizes possibilities and manners of solving them, and succeeds in realizing successful psycho-social functioning. Developed cognitive abilities enable a child to recognize and understand her/his own reactions in different situations and develop manners of reacting, which leads to strengthening psycho-social safety and adapting behavior in accordance with her/his age and abilities.

  11. Origin of specific chromosome aberration in radiation-induced leukemia

    International Nuclear Information System (INIS)

    Ban, Nobuhiko; Kai, Michiaki; Masuno, Yoko

    2005-01-01

    The theme in the title is discussed from the four aspects of specific chromosome aberration (sAb) patterns in radiation-induced leukemia (RIL), possibility for radiation to induce the sAb in RIL, any evidence for participation of delayed aberration to form sAb and the proportion of such healthy humans as having the specifically rearranged genome. Data of sAb observed in leukemia of 25 A-bomb survivors and of 38 patients post radiotherapy of cancers give a rather common pattern. However, many inconsistent results are obtained for sAb in patients post radiotherapy, A-bomb survivors, residents living in radio-contaminated houses in Taipei, in vitro exposure, and Chernobyl residents. At present, any clear evidence is available neither for sAb derived from the delayed aberration nor for estimating the proportion with the specifically rearranged gene. As above, it is unlikely that radiation induces such a translocation abnormality as BCR-ABL specifically seen in leukemia, and this aspect will be important for studies on the genesis of RIL and its risk assessment. (S.I.)

  12. Space Active Optics: toward optimized correcting mirrors for future large spaceborne observatories

    Science.gov (United States)

    Laslandes, Marie; Hugot, Emmanuel; Ferrari, Marc; Lemaitre, Gérard; Liotard, Arnaud

    2011-10-01

    Wave-front correction in optical instruments is often needed, either to compensate Optical Path Differences, off-axis aberrations or mirrors deformations. Active optics techniques are developed to allow efficient corrections with deformable mirrors. In this paper, we will present the conception of particular deformation systems which could be used in space telescopes and instruments in order to improve their performances while allowing relaxing specifications on the global system stability. A first section will be dedicated to the design and performance analysis of an active mirror specifically designed to compensate for aberrations that might appear in future 3m-class space telescopes, due to lightweight primary mirrors, thermal variations or weightless conditions. A second section will be dedicated to a brand new design of active mirror, able to compensate for given combinations of aberrations with a single actuator. If the aberrations to be corrected in an instrument and their evolutions are known in advance, an optimal system geometry can be determined thanks to the elasticity theory and Finite Element Analysis.

  13. Aerial Photography and Imagery, Ortho-Corrected, Historic 1958 black and white aerial photography for Wicomico County, Maryland. Imagery was scanned from historic hard copy images and georeferenced to current imagery. This data is available via map service., Published in 2010, 1:12000 (1in=1000ft) scale, Eastern Shore Regional GIS Cooperative.

    Data.gov (United States)

    NSGIC Regional | GIS Inventory — Aerial Photography and Imagery, Ortho-Corrected dataset current as of 2010. Historic 1958 black and white aerial photography for Wicomico County, Maryland. Imagery...

  14. Scanning transmission electron microscope

    NARCIS (Netherlands)

    Kruit, P.

    2006-01-01

    The invention relates to a scanning transmission electron microscope comprising an electron source, an electron accelerator and deflection means for directing electrons emitted by the electron source at an object to be examined, and in addition a detector for detecting electrons coming from the

  15. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake ...

  16. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... may be performed to measure the level of thyroid hormones in your blood. You may be told not to eat for several hours before your exam because eating can affect the ... as well. Thyroid Scan You will be positioned on an examination ...

  17. Dialogue scanning measuring systems

    International Nuclear Information System (INIS)

    Borodyuk, V.P.; Shkundenkov, V.N.

    1985-01-01

    The main developments of scanning measuring systems intended for mass precision processsing of films in nuclear physics problems and in related fields are reviewed. A special attention is paid to the problem of creation of dialogue systems which permit to simlify the development of control computer software

  18. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... you: have had any tests, such as an x-ray or CT scan, surgeries or treatments using iodinated ... page How does the procedure work? With ordinary x-ray examinations, an image is made by passing x- ...

  19. SPM: Scanning positron microscope

    Directory of Open Access Journals (Sweden)

    Marcel Dickmann

    2015-08-01

    Full Text Available The Munich scanning positron microscope, operated by the Universität der Bundeswehr München and the Technische Universität München, located at NEPOMUC, permits positron lifetime measurements with a lateral resolution in the µm range and within an energy range of 1 – 20 keV.

  20. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... rate at which the body converts food to energy. top of page What are some common uses of the procedure? The thyroid scan is used ... the patient's body. In contrast, nuclear medicine procedures use a ... off a small amount of energy in the form of gamma rays. Special cameras ...

  1. Scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Binnig, G.; Rohrer, H.

    1983-01-01

    Based on vacuum tunneling, a novel type of microscope, the scanning tunneling microscope (STM) was developed. It has an unprecedented resolution in real space on an atomic scale. The authors review the important technical features, illustrate the power of the STM for surface topographies and discuss its potential in other areas of science and technology. (Auth.)

  2. Terahertz scanning probe microscope

    NARCIS (Netherlands)

    Klapwijk, T.M.

    2014-01-01

    The invention provides aterahertz scanning probe microscope setup comprising (i) a terahertz radiation source configured to generate terahertz radiation; (ii) a terahertz lens configured to receive at least part of the terahertz radiation from the terahertz radiation source; (iii) a cantilever unit

  3. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... the equipment look like? How does the procedure work? How is the procedure performed? What will I experience during and after the procedure? Who interprets the results and how do I get them? What are the benefits vs. risks? What are the limitations of the Thyroid Scan ...

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... the structure and function of the thyroid. The thyroid is a gland in the neck that controls metabolism , a chemical process that regulates the rate at which the body converts food to energy. top of page What are some common uses of the procedure? The thyroid scan is used to determine the size, shape ...

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top of page ... and Neck Cancer Treatment Radioactive Iodine (I-131) Therapy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear ... to Thyroid Scan and Uptake ...

  6. Scanning bubble chamber pictures

    CERN Multimedia

    1974-01-01

    These were taken at the 2 m hydrogen bubble chamber. The photo shows an early Shiva system where the pre-measurements needed to qualify the event were done manually (cf photo 7408136X). The scanning tables were located in bld. 12. Gilberte Saulmier sits on foreground, Inge Arents at centre.

  7. Bone scan in rheumatology

    International Nuclear Information System (INIS)

    Morales G, R.; Cano P, R.; Mendoza P, R.

    1993-01-01

    In this chapter a revision is made concerning different uses of bone scan in rheumatic diseases. These include reflex sympathetic dystrophy, osteomyelitis, spondyloarthropaties, metabolic bone diseases, avascular bone necrosis and bone injuries due to sports. There is as well some comments concerning pediatric pathology and orthopedics. (authors). 19 refs., 9 figs

  8. Scan This Book!

    Science.gov (United States)

    Albanese, Andrew Richard

    2007-01-01

    In this article, the author presents an interview with Brewster Kahle, leader of the Open Content Alliance (OCA). OCA book scan program is an alternative to Google's library project that aims to make books accessible online. In this interview, Kahle discusses his views on the challenges of getting books on the Web, on Google's library…

  9. Abscess scan - radioactive

    Science.gov (United States)

    ... blood cells are tagged with a radioactive substance ( radioisotope ) called indium. The cells are then injected back ... you have or had any of the following medical conditions, procedures, or treatments, as they can interfere with ... Often, other imaging tests such as an ultrasound or CT scan ...

  10. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... or less. top of page What will I experience during and after the procedure? Most thyroid scan ... areas. Outside links: For the convenience of our users, RadiologyInfo .org provides links to relevant websites. RadiologyInfo. ...

  11. Thoracic spine CT scan

    Science.gov (United States)

    ... Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team. CT Scans Read more Spinal Cord Injuries Read more Spine ...

  12. Aberrant muscle syndrome: hypertrophy of the hand and arm due to aberrant muscles with or without hypertrophy of the muscles.

    Science.gov (United States)

    Ogino, Toshihiko; Satake, Hiroshi; Takahara, Masatoshi; Kikuchi, Noriaki; Watanabe, Tadayosi; Iba, Kousuke; Ishii, Seiichi

    2010-06-01

    Five patients were reported in our congenital anomaly registry who had six hands in total with muscular hyperplasia, aberrant muscles, ulnar drift of the fingers in the metacarpophalangeal (MP) joints, flexion contractures of the MP joints, and enlargement of the metacarpal spaces. Thirty patients with unilateral involvement of this condition have been reported previously. We reviewed these cases and found that the condition varied in severity and that it was reported using different names. However, this condition seems different from true macrodactyly and multiple camptodactyly, including windblown hand, and seems to be an isolated entity of congenital upper limb anomaly. The authors recommend 'aberrant muscle syndrome' or 'accessory muscle syndrome' as a diagnostic name, because this seems to be the most common pathological finding in this condition.

  13. Minimizing camera-eye optical aberrations during the 3D reconstruction of retinal structures

    Science.gov (United States)

    Aldana-Iuit, Javier; Martinez-Perez, M. Elena; Espinosa-Romero, Arturo; Diaz-Uribe, Rufino

    2010-05-01

    3D reconstruction of blood vessels is a powerful visualization tool for physicians, since it allows them to refer to qualitative representation of their subject of study. In this paper we propose a 3D reconstruction method of retinal vessels from fundus images. The reconstruction method propose herein uses images of the same retinal structure in epipolar geometry. Images are preprocessed by RISA system for segmenting blood vessels and obtaining feature points for correspondences. The correspondence points process is solved using correlation. The LMedS analysis and Graph Transformation Matching algorithm are used for outliers suppression. Camera projection matrices are computed with the normalized eight point algorithm. Finally, we retrieve 3D position of the retinal tree points by linear triangulation. In order to increase the power of visualization, 3D tree skeletons are represented by surfaces via generalized cylinders whose radius correspond to morphological measurements obtained by RISA. In this paper the complete calibration process including the fundus camera and the optical properties of the eye, the so called camera-eye system is proposed. On one hand, the internal parameters of the fundus camera are obtained by classical algorithms using a reference pattern. On the other hand, we minimize the undesirable efects of the aberrations induced by the eyeball optical system assuming that contact enlarging lens corrects astigmatism, spherical and coma aberrations are reduced changing the aperture size and eye refractive errors are suppressed adjusting camera focus during image acquisition. Evaluation of two self-calibration proposals and results of 3D blood vessel surface reconstruction are presented.

  14. Bone scans in nasopharyngeal carcinoma: local experience

    International Nuclear Information System (INIS)

    Tiong, S.

    2004-01-01

    scans (both treated), 2 had false positive bone scans (1 newly diagnosed and 1 treated), and 2 (both treated) had true negative bone scan with no increased radio-tracer uptake and no confirmed X ray imagings for metastasis.In the true positive group of patients, the radiologists were correct in their reports of consistency of bone metastasis in 3 patients and uncertain in their reports of differential causes of the increased uptake in 1 patient. In the false positive group of patients, the radiologist were correct in their reports of causes other than bone metastasis in 3 patients, incorrect in their reports of consistency of bone metastasis in 2 patients, and uncertain in their reports of differential causes of the increased uptake in 13 patients. Showing the positive bone scans are 7 patients having degenerative spine disease on Xray imagings and 3 dental diseases on clinical findings.The ages of the patients range from 18 to 88 years, with a mean age being 50.5. In the 41 patients, 35 patients had advanced stages ( Stages III and IV ) and 6 early stages ( Stages I and II). Among the patients of advanced stages, 3 having true positive and 13 false positives, whereas among the patients of early stages, 1 true positive and 1 false positive. Discussion: The results show that 44% of the patients had positive bone scans and this could be due to large number of patients (10/41)having degenerative spine diseases and dental diseases.These show that the bone scans have high sensitivity. However they do not have high specificity as only 9.8% of total or 2.2% (4/18) of the positive bone scans patients have true positives. The specificity in the treated group of patients appear to be higher being 25% (3/12 treated patients)The bone scans are therefore regarded as a screening test and if positive, they help guide and target the Xray imaging studies to confirm the bone metastasis one way or another. It is therefore useful in NPC management. The radiologists were most of the times

  15. Real-time wavefront correction system using a zonal deformable mirror and a Hartmann sensor

    International Nuclear Information System (INIS)

    Salmon, J.T.; Bliss, E.S.; Long, T.W.; Orham, E.L.; Presta, R.W.; Swift, C.D.; Ward, R.S.

    1991-07-01

    We have developed an adaptive optics system that corrects up to five waves of 2nd-order and 3rd-order aberrations in a high-power laser beam to less than 1/10th wave RMS. The wavefront sensor is a Hartmann sensor with discrete lenses and position-sensitive photodiodes; the deformable mirror uses piezoelectric actuators with feedback from strain gauges bonded to the stacks. The controller hardware uses a VME bus. The system removes thermally induced aberrations generated in the master-oscillator-power-amplifier chains of a dye laser, as well as aberrations generated in beam combiners and vacuum isolation windows for average output powers exceeding 1 kW. The system bandwidth is 1 Hz, but higher bandwidths are easily attainable

  16. Environmental transmission electron microscopy for catalyst materials using a spherical aberration corrector.

    Science.gov (United States)

    Takeda, Seiji; Kuwauchi, Yasufumi; Yoshida, Hideto

    2015-04-01

    Atomic resolution has been obtained using environmental transmission electron microscopy (ETEM) by installing a spherical aberration corrector (Cs-corrector) on the objective lens. Simultaneously, the technology for controlling the environment around a specimen in ETEM has advanced significantly in the past decade. Quantification methodology has recently been established for deriving relevant experimental data in catalyst materials from substantial and systematic ETEM observation at the atomic scale. With this background, this paper summarizes aspects of the evolutional microscopy technique: necessary conditions for atomic resolution in ETEM; reduction of the scattering of electrons by the medium surrounding a specimen; and an environmental cell for structural imaging of a crystalline specimen. The high spatial resolution of a Cs-corrected ETEM is demonstrated for different observation conditions. After statistical analysis combined with numerical image analysis of ETEM data is briefly described, the recent applications of the Cs-corrected ETEM to catalyst materials are reviewed. For gold nanoparticulate catalysts, the structural information on the reaction sites and adsorption sites are deduced. For Pt nanoparticulate catalysts, ETEM studies elucidate the correlation between the catalytic activity and the morphology of the nanoparticles. These studies also reveal oxidation and reduction on the topmost Pt surface layer at the atomic scale. Finally, current issues and the future perspectives of Cs-corrected ETEM are summarized, including the reproducibility of ETEM observation data, the control of environments, the critical evaluation of electron irradiation effects, the full implementation of transmission electron microscopy technology in ETEM, and the safety issues for an ETEM laboratory. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Mammographic scanning equalization radiography

    International Nuclear Information System (INIS)

    Sabol, J.M.; Soutar, I.C.; Plewe, D.B.

    1990-01-01

    This paper reports on conventional x-ray mammography that suffers from poor visualization of low-contrast lesions and microcalcifications in regions where variations in breast thickness and parenchymal pattern result in suboptimal film exposure and contrast. MSER overcomes this limitation by equalizing the film exposure into the range of maximum film contrast, independent of variations in breast architecture. A prototype MSER system has been developed for imaging breast phantoms in which a Min-R cassette is exposed by scanning a small (4-cm 2 ) beam of pulsed (40-Hz) x-rays (30 KVp) over the breast phantom in a raster fashion while measuring the transmission with a scanning detector. Feedback of the transmission information modulates the width of each x-ray pulse to equalize the film exposure over the entire image

  18. The laser scanning camera

    International Nuclear Information System (INIS)

    Jagger, M.

    The prototype development of a novel lenseless camera is reported which utilises a laser beam scanned in a raster by means of orthogonal vibrating mirrors to illuminate the field of view. Laser light reflected from the scene is picked up by a conveniently sited photosensitive device and used to modulate the brightness of a T.V. display scanned in synchronism with the moving laser beam, hence producing a T.V. image of the scene. The camera which needs no external lighting system can act in either a wide angle mode or by varying the size and position of the raster can be made to zoom in to view in detail any object within a 40 0 overall viewing angle. The resolution and performance of the camera are described and a comparison of these aspects is made with conventional T.V. cameras. (author)

  19. Scanning probe microscopy

    International Nuclear Information System (INIS)

    Mainsbridge, B.

    1994-01-01

    In late 1959, Richard Feynman observed that manoeuvring atoms was something that could be done in principle but has not been done, 'because we are too big'. In 1982, the scanning tunnelling microscope (STM) was invented and is now a central tool for the construction of nanoscale devices in what was known as molecular engineering, and now, nanotechnology. The principles of the microscope are outlined and references are made to other scanning devices which have evolved from the original invention. The method of employment of the STM as a machine tool is described and references are made to current speculations on applications of the instrument in nanotechnology. A short bibliography on this topic is included. 27 refs., 7 figs

  20. IMEF gamma scanning system

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Sang Yeol; Park, Dae Kyu; Ahn, Sang Bok; Ju, Yong Sun; Jeon, Yong Bum

    1997-06-01

    The gamma scanning system which is installed in IMEF is the equipment obtaining the gamma ray spectrum from irradiated fuels. This equipment could afford the useful data relating spent fuels like as burn-up measurements. We describe the specifications of the equipment and its accessories, and also described its operation procedure so that an operator can use this report as the operation procedure. (author). 1 tab., 11 figs., 11 refs.