WorldWideScience

Sample records for multiple exposure holograms

  1. Faster processing of multiple spatially-heterodyned direct to digital holograms

    Hanson, Gregory R [Clinton, TN; Bingham, Philip R [Knoxville, TN

    2008-09-09

    Systems and methods are described for faster processing of multiple spatially-heterodyned direct to digital holograms. A method includes of obtaining multiple spatially-heterodyned holograms, includes: digitally recording a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; digitally recording a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first object beam; applying a first digital filter to cut off signals around the first original origin and performing an inverse Fourier transform on the result; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam; and applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result, wherein digitally recording the first spatially-heterodyned hologram is completed before digitally recording the second spatially-heterodyned hologram and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

  2. Phase Holograms In PMMA

    Maker, Paul D.; Muller, Richard E.

    1994-01-01

    Complex, computer-generated phase holograms written in thin films of poly(methyl methacrylate) (PMMA) by process of electron-beam exposure followed by chemical development. Spatial variations of phase delay in holograms quasi-continuous, as distinquished from stepwise as in binary phase holograms made by integrated-circuit fabrication. Holograms more precise than binary holograms. Greater continuity and precision results in decreased scattering loss and increased imaging efficiency.

  3. Coherent noise reduction in digital holographic microscopy by averaging multiple holograms recorded with a multimode laser.

    Pan, Feng; Yang, Lizhi; Xiao, Wen

    2017-09-04

    In digital holographic microscopy (DHM), it is undesirable to observe coherent noise in the reconstructed images. The sources of the noise are mainly the parasitic interference fringes caused by multiple reflections and the speckle pattern caused by the optical scattering on the object surface. Here we propose a noise reduction approach in DHM by averaging multiple holograms recorded with a multimode laser. Based on the periodicity of the temporal coherence of a multimode semiconductor laser, we acquire a series of holograms by changing the optical path length difference between the reference beam and object beam. Because of the use of low coherence light, we can remove the parasitic interference fringes caused by multiple reflections in the holograms. In addition, the coherent noise patterns change in this process due to the different optical paths. Therefore, the coherent noise can be reduced by averaging the multiple reconstructions with uncorrelated noise patterns. Several experiments have been carried out to validate the effectiveness of the proposed approach for coherent noise reduction in DHM. It is shown a remarkable improvement both in amplitude imaging quality and phase measurement accuracy.

  4. Scanning holograms

    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

  5. Computer-generated holograms by multiple wavefront recording plane method with occlusion culling.

    Symeonidou, Athanasia; Blinder, David; Munteanu, Adrian; Schelkens, Peter

    2015-08-24

    We propose a novel fast method for full parallax computer-generated holograms with occlusion processing, suitable for volumetric data such as point clouds. A novel light wave propagation strategy relying on the sequential use of the wavefront recording plane method is proposed, which employs look-up tables in order to reduce the computational complexity in the calculation of the fields. Also, a novel technique for occlusion culling with little additional computation cost is introduced. Additionally, the method adheres a Gaussian distribution to the individual points in order to improve visual quality. Performance tests show that for a full-parallax high-definition CGH a speedup factor of more than 2,500 compared to the ray-tracing method can be achieved without hardware acceleration.

  6. The hologram principles and techniques

    Richardson, Martin J

    2018-01-01

    Written by Martin Richardson (an acclaimed leader and pioneer in the field) and John Wiltshire, The Hologram: Principles and Techniques is an important book that explores the various types of hologram in their multiple forms and explains how to create and apply the technology. The authors offer an insightful overview of the currently available recording materials, chemical formulas, and laser technology that includes the history of phase imaging and laser science. Accessible and comprehensive, the text contains a step-by-step guide to the production of holograms. In addition, The Hologram outlines the most common problems encountered in producing satisfactory images in the laboratory, as well as dealing with the wide range of optical and chemical techniques used in commercial holography. The Hologram is a well-designed instructive tool, involving three distinct disciplines: physics, chemistry, and graphic arts. This vital resource offers a guide to the development and understanding of the recording of mater...

  7. Holograms a cultural history

    Johnston, Sean F

    2016-01-01

    Holograms have been in the public eye for over a half-century, but their influences have deeper cultural roots. No other visual experience is quite like interacting with holograms; no other cultural product melds the technological sublime with magic and optimism in quite the same way. As holograms have evolved, they have left their audiences alternately fascinated, bemused, inspired or indifferent. From expressions of high science to countercultural art to consumer security, holograms have represented modernity, magic and materialism. Their most pervasive impact has been to galvanize hopeful technological dreams. This book explores how holograms found a place in distinct cultural settings. Engineers, artists, hippies and hobbyists have played with, and dreamed about, holograms. This book explores the technical attractions and cultural uses of the hologram, how they were shaped by what came before them, and how they have matured to shape our notional futures. Today, holograms are in our pockets (as identity do...

  8. Three-dimensional hologram display system

    Mintz, Frederick (Inventor); Chao, Tien-Hsin (Inventor); Bryant, Nevin (Inventor); Tsou, Peter (Inventor)

    2009-01-01

    The present invention relates to a three-dimensional (3D) hologram display system. The 3D hologram display system includes a projector device for projecting an image upon a display medium to form a 3D hologram. The 3D hologram is formed such that a viewer can view the holographic image from multiple angles up to 360 degrees. Multiple display media are described, namely a spinning diffusive screen, a circular diffuser screen, and an aerogel. The spinning diffusive screen utilizes spatial light modulators to control the image such that the 3D image is displayed on the rotating screen in a time-multiplexing manner. The circular diffuser screen includes multiple, simultaneously-operated projectors to project the image onto the circular diffuser screen from a plurality of locations, thereby forming the 3D image. The aerogel can use the projection device described as applicable to either the spinning diffusive screen or the circular diffuser screen.

  9. Quantum volume hologram

    Vasilyev, Denis V.; Sokolov, Ivan V.; Polzik, Eugene S.

    2010-01-01

    We propose a scheme for parallel spatially multimode quantum memory for light. The scheme is based on a counterpropagating quantum signal wave and a strong classical reference wave as in a classical volume hologram and therefore can be called a quantum volume hologram. The medium for the hologram consists of a spatially extended ensemble of atoms placed in a magnetic field. The write-in and readout of this quantum hologram is as simple as that of its classical counterpart and consists of a single-pass illumination. In addition, we show that the present scheme for a quantum hologram is less sensitive to diffraction and therefore is capable of achieving a higher density of storage of spatial modes as compared to previous proposals. We present a feasibility study and show that experimental implementation is possible with available cold atomic samples. A quantum hologram capable of storing entangled images can become an important ingredient in quantum information processing and quantum imaging.

  10. Anticounterfeit holograms in China

    Hsu, Dahsiung; Zhou, Jing; Pei, Wen; Li, Qiang; Huang, Xuhuai; Cao, Yulin

    1995-02-01

    The Chinese holography industry has been given an enormous boost by the energetic sales and technology transfer of several western businesses. It is a fast growing industry which can keep up with domestic demand for anti-counterfeit embossed holograms because product counterfeiting is so rife internally. Tax papers, stamps, plastic cards, identification cards, and many packaged goods are authenticated with embossed holograms. Up to now, about 1,000 kinds of products in China have used holograms to protect themselves. Anti-counterfeit holograms with secret codes have also been used. After dependence on imports, China is rapidly developing its own sources of equipment, holographic materials, and embossing substrates. The quality of this equipment and materials is improving. The new Chinese Holography Association, a national industry association aiming to develop the application of holograms and to promote cooperation between organizations, was established in 1993. The CHA has requested affiliation to the International Hologram Manufacturers Association, a move which should improve the communication between the Chinese industry and the rest of the world industry.

  11. Impulse holograms in amorphous semiconductor films

    Ozols, A.; Ivanovs, G.; Lazarevs, S.

    2002-01-01

    Impulse hologram recording in amorphous chalcogenide semiconductor films with pulse duration from minutes to picoseconds is considered. Nanosecond pulses are shown to be optimal due to the nonlinearity to films. Millisecond impulse hologram recording is experimentally studied. It is found that about 500 times lower exposure is needed to reach the same diffraction efficiency when compared to CW case. The millisecond recording is non-permanent. A nonlinear photoinduced recharging of localized states in the band gap is found to be responsible for the millisecond recording. It can be applied for non-permanent optical storage and optical information processing. (authors)

  12. Reprocessing of nonoptimally exposed holograms

    Phipps, G.S.; Robertson, C.E.; Tamashiro, F.M.

    1980-01-01

    Two reprocessing techniques have been investigated that are capable of correcting the effects of nonoptimum optical density of photographic amplitude holograms recorded on Agfa-Gevaert type 10E75 plates. In some cases a reprocessed hologram will exhibit a diffraction efficiency even higher than that obtainable from a hologram exposed and processed to the optimum density. The SNR of the reprocessed holograms is much higher than that of the same holograms belached with cupric bromide. In some cases the SNR approaches the optimum value for a properly exposed amplitude hologram. Subjective image quality and resolution of reprocessed hologram reconstructins appear to be no different than for normal single-development holograms. Repeated reprocessing is feasible and in some cases desirable as a means of increasing diffraction efficiency

  13. Holograms as Teaching Agents

    Walker, Robin A.

    2013-02-01

    Hungarian physicist Dennis Gabor won the Pulitzer Prize for his 1947 introduction of basic holographic principles, but it was not until the invention of the laser in 1960 that research scientists, physicians, technologists and the general public began to seriously consider the interdisciplinary potentiality of holography. Questions around whether and when Three-Dimensional (3-D) images and systems would impact American entertainment and the arts would be answered before educators, instructional designers and students would discover how much Three-Dimensional Hologram Technology (3DHT) would affect teaching practices and learning environments. In the following International Symposium on Display Holograms (ISDH) poster presentation, the author features a traditional board game as well as a reflection hologram to illustrate conventional and evolving Three-Dimensional representations and technology for education. Using elements from the American children's toy Operation® (Hasbro, 2005) as well as a reflection hologram of a human brain (Ko, 1998), this poster design highlights the pedagogical effects of 3-D images, games and systems on learning science. As teaching agents, holograms can be considered substitutes for real objects, (human beings, organs, and animated characters) as well as agents (pedagogical, avatars, reflective) in various learning environments using many systems (direct, emergent, augmented reality) and electronic tools (cellphones, computers, tablets, television). In order to understand the particular importance of utilizing holography in school, clinical and public settings, the author identifies advantages and benefits of using 3-D images and technology as instructional tools.

  14. Fundamental superstrings as holograms

    Dabholkar, A.; Murthy, S.

    2007-06-01

    The worldsheet of a macroscopic fundamental superstring in the Green-Schwarz light-cone gauge is viewed as a possible boundary hologram of the near horizon region of a small black string. For toroidally compactified strings, the hologram has global symmetries of AdS 3 x S d-1 x T 8-d ( d = 3, . . . , 8), only some of which extend to local conformal symmetries. We construct the bulk string theory in detail for the particular case of d = 3. The symmetries of the hologram are correctly reproduced from this exact worldsheet description in the bulk. Moreover, the central charge of the boundary Virasoro algebra obtained from the bulk agrees with the Wald entropy of the associated small black holes. This construction provides an exact CFT description of the near horizon region of small black holes both in Type-II and heterotic string theory arising from multiply wound fundamental superstrings. (author)

  15. Fundamental superstrings as holograms

    Dabholkar, Atish; Murthy, Sameer

    2008-01-01

    The worldsheet of a macroscopic fundamental superstring in the Green-Schwarz light-cone gauge is viewed as a possible boundary hologram of the near horizon region of a small black string. For toroidally compactified strings, the hologram has global symmetries of AdS 3 x S d-1 x T 8-d (d = 3, ..., 8), only some of which extend to local conformal symmetries. We construct the bulk string theory in detail for the particular case of d = 3. The symmetries of the hologram are correctly reproduced from this exact worldsheet description in the bulk. Moreover, the central charge of the boundary Virasoro algebra obtained from the bulk agrees with the Wald entropy of the associated small black holes. This construction provides an exact CFT description of the near horizon region of small black holes both in Type-II and heterotic string theory arising from multiply wound fundamental superstrings

  16. Reconfigurable Optical Interconnections Via Dynamic Computer-Generated Holograms

    Liu, Hua-Kuang (Inventor); Zhou, Shao-Min (Inventor)

    1996-01-01

    A system is presented for optically providing one-to-many irregular interconnections, and strength-adjustable many-to-many irregular interconnections which may be provided with strengths (weights) w(sub ij) using multiple laser beams which address multiple holograms and means for combining the beams modified by the holograms to form multiple interconnections, such as a cross-bar switching network. The optical means for interconnection is based on entering a series of complex computer-generated holograms on an electrically addressed spatial light modulator for real-time reconfigurations, thus providing flexibility for interconnection networks for large-scale practical use. By employing multiple sources and holograms, the number of interconnection patterns achieved is increased greatly.

  17. Holograms for acoustics.

    Melde, Kai; Mark, Andrew G; Qiu, Tian; Fischer, Peer

    2016-09-22

    Holographic techniques are fundamental to applications such as volumetric displays, high-density data storage and optical tweezers that require spatial control of intricate optical or acoustic fields within a three-dimensional volume. The basis of holography is spatial storage of the phase and/or amplitude profile of the desired wavefront in a manner that allows that wavefront to be reconstructed by interference when the hologram is illuminated with a suitable coherent source. Modern computer-generated holography skips the process of recording a hologram from a physical scene, and instead calculates the required phase profile before rendering it for reconstruction. In ultrasound applications, the phase profile is typically generated by discrete and independently driven ultrasound sources; however, these can only be used in small numbers, which limits the complexity or degrees of freedom that can be attained in the wavefront. Here we introduce monolithic acoustic holograms, which can reconstruct diffraction-limited acoustic pressure fields and thus arbitrary ultrasound beams. We use rapid fabrication to craft the holograms and achieve reconstruction degrees of freedom two orders of magnitude higher than commercial phased array sources. The technique is inexpensive, appropriate for both transmission and reflection elements, and scales well to higher information content, larger aperture size and higher power. The complex three-dimensional pressure and phase distributions produced by these acoustic holograms allow us to demonstrate new approaches to controlled ultrasonic manipulation of solids in water, and of liquids and solids in air. We expect that acoustic holograms will enable new capabilities in beam-steering and the contactless transfer of power, improve medical imaging, and drive new applications of ultrasound.

  18. Phase holograms in polymethyl methacrylate

    Maker, P. D.; Muller, R. E.

    1992-01-01

    A procedure is described for the fabrication of complex computer-generated phase holograms in polymethyl methacrylate (PMMA) by means of partial-exposure e-beam lithography and subsequent carefully controlled partial development. Following the development, the pattern appears (rendered in relief) in the PMMA, which then acts as the phase-delay medium. The devices fabricated were designed with 16 equal phase steps per retardation cycle, were up to 3 mm square, and consisted of up to 10 millions of 0.3-2.0-micron square pixels. Data files were up to 60 Mb-long, and the exposure times ranged to several hours. A Fresnel phase lens was fabricated with a diffraction-limited optical performance of 83-percent efficiency.

  19. Making Holograms at School

    Robinson, M. L. A.; Saunders, A. P.

    1973-01-01

    Discusses holography, a process by which a three-dimensional image of an object can be completely recorded on a photographic film or plate. Introduces hologram theory with a view to presenting it to senior high school students, and explains how the apparently very great experimental difficulties can be overcome. (JR)

  20. Strain Multiplexed Metasurface Holograms on a Stretchable Substrate.

    Malek, Stephanie C; Ee, Ho-Seok; Agarwal, Ritesh

    2017-06-14

    We demonstrate reconfigurable phase-only computer-generated metasurface holograms with up to three image planes operating in the visible regime fabricated with gold nanorods on a stretchable polydimethylsiloxane substrate. Stretching the substrate enlarges the hologram image and changes the location of the image plane. Upon stretching, these devices can switch the displayed holographic image between multiple distinct images. This work opens up the possibilities for stretchable metasurface holograms as flat devices for dynamically reconfigurable optical communication and display. It also confirms that metasurfaces on stretchable substrates can serve as platform for a variety of reconfigurable optical devices.

  1. High Dynamic Range Imaging Using Multiple Exposures

    Hou, Xinglin; Luo, Haibo; Zhou, Peipei; Zhou, Wei

    2017-06-01

    It is challenging to capture a high-dynamic range (HDR) scene using a low-dynamic range (LDR) camera. This paper presents an approach for improving the dynamic range of cameras by using multiple exposure images of same scene taken under different exposure times. First, the camera response function (CRF) is recovered by solving a high-order polynomial in which only the ratios of the exposures are used. Then, the HDR radiance image is reconstructed by weighted summation of the each radiance maps. After that, a novel local tone mapping (TM) operator is proposed for the display of the HDR radiance image. By solving the high-order polynomial, the CRF can be recovered quickly and easily. Taken the local image feature and characteristic of histogram statics into consideration, the proposed TM operator could preserve the local details efficiently. Experimental result demonstrates the effectiveness of our method. By comparison, the method outperforms other methods in terms of imaging quality.

  2. Real-time capture and reconstruction system with multiple GPUs for a 3D live scene by a generation from 4K IP images to 8K holograms.

    Ichihashi, Yasuyuki; Oi, Ryutaro; Senoh, Takanori; Yamamoto, Kenji; Kurita, Taiichiro

    2012-09-10

    We developed a real-time capture and reconstruction system for three-dimensional (3D) live scenes. In previous research, we used integral photography (IP) to capture 3D images and then generated holograms from the IP images to implement a real-time reconstruction system. In this paper, we use a 4K (3,840 × 2,160) camera to capture IP images and 8K (7,680 × 4,320) liquid crystal display (LCD) panels for the reconstruction of holograms. We investigate two methods for enlarging the 4K images that were captured by integral photography to 8K images. One of the methods increases the number of pixels of each elemental image. The other increases the number of elemental images. In addition, we developed a personal computer (PC) cluster system with graphics processing units (GPUs) for the enlargement of IP images and the generation of holograms from the IP images using fast Fourier transform (FFT). We used the Compute Unified Device Architecture (CUDA) as the development environment for the GPUs. The Fast Fourier transform is performed using the CUFFT (CUDA FFT) library. As a result, we developed an integrated system for performing all processing from the capture to the reconstruction of 3D images by using these components and successfully used this system to reconstruct a 3D live scene at 12 frames per second.

  3. Photopolymerizable hologram materials

    Calvo, Maria L.

    2009-01-01

    It is presented an overview of the current performances achieved in holography for the implementation of holographic gratings in photopolymerizable hologram materials. In particular, we dedicate an interest for the results associated to photomaterials belonging to the class of photopolymerizable glasses and the current applications. An overview of the main results on the current research at the Interdisciplinary Group for Optical Computing (GICO-UCM) at the Complutense University of Madrid is reported. (Author)

  4. Use of Computer-Generated Holograms in Security Hologram Applications

    Bulanovs A.

    2016-10-01

    Full Text Available The article discusses the use of computer-generated holograms (CGHs for the application as one of the security features in the relief-phase protective holograms. An improved method of calculating CGHs is presented, based on ray-tracing approach in the case of interference of parallel rays.

  5. Reconstruction of on-axis lensless Fourier transform digital hologram with the screen division method

    Jiang, Hongzhen; Liu, Xu; Liu, Yong; Li, Dong; Chen, Zhu; Zheng, Fanglan; Yu, Deqiang

    2017-10-01

    An effective approach for reconstructing on-axis lensless Fourier Transform digital hologram by using the screen division method is proposed. Firstly, the on-axis Fourier Transform digital hologram is divided into sub-holograms. Then the reconstruction result of every sub-hologram is obtained according to the position of corresponding sub-hologram in the hologram reconstruction plane with Fourier transform operation. Finally, the reconstruction image of on-axis Fourier Transform digital hologram can be acquired by the superposition of the reconstruction result of sub-holograms. Compared with the traditional reconstruction method with the phase shifting technology, in which multiple digital holograms are required to record for obtaining the reconstruction image, this method can obtain the reconstruction image with only one digital hologram and therefore greatly simplify the recording and reconstruction process of on-axis lensless Fourier Transform digital holography. The effectiveness of the proposed method is well proved with the experimental results and it will have potential application foreground in the holographic measurement and display field.

  6. Fluorescent holograms with albumin-acrylamide

    Ordóñez-Padilla, M. J.; Olivares-Pérez, A.; Fuentes-Tapia, I.

    2014-02-01

    We describe fluorescent holograms were made with photosensitive films of albumin (protein) quail, used as modified matrices. Albumin is mixed with acrylamide and eosin Y. Therefore, prepare a photosensitive emulsion and solid hydrated with the ability to phase transmission holograms and volume (VPH). Eosin Y is a fluorescent agent that acts as a photo-sensitizing dye which stimulates the polymerization of acrylamide. To record the interference pattern produced by two waves superimposed on the modified matrix, we use a He-Cd laser. To reconstruct the diffraction pattern is observed with He- Ne laser, λ = 632.8nm, the material is self-developing properties. Measure the diffraction efficiency of the diffracted orders (η[-1, +1]) as a function of exposure energy. We work with various thicknesses and measure the variation of the refractive index using the coupled wave theory of Kogelnik, the holographic gratings meet Bragg condition.

  7. Computer-Generated Microwave Holograms.

    Leming, Charles W.; Hastings, Orestes Patterson, III

    1980-01-01

    Described is the phasor method of superposition of waves. The intensity pattern from a system of microwave sources is calculated point by point on a plane corresponding to a film emulsion, and then printed and directly converted to a hologram for 3-cm microwaves. Calculations, construction, and viewing of holograms are included. (Author/DS)

  8. Helicity multiplexed broadband metasurface holograms.

    Wen, Dandan; Yue, Fuyong; Li, Guixin; Zheng, Guoxing; Chan, Kinlong; Chen, Shumei; Chen, Ming; Li, King Fai; Wong, Polis Wing Han; Cheah, Kok Wai; Pun, Edwin Yue Bun; Zhang, Shuang; Chen, Xianzhong

    2015-09-10

    Metasurfaces are engineered interfaces that contain a thin layer of plasmonic or dielectric nanostructures capable of manipulating light in a desirable manner. Advances in metasurfaces have led to various practical applications ranging from lensing to holography. Metasurface holograms that can be switched by the polarization state of incident light have been demonstrated for achieving polarization multiplexed functionalities. However, practical application of these devices has been limited by their capability for achieving high efficiency and high image quality. Here we experimentally demonstrate a helicity multiplexed metasurface hologram with high efficiency and good image fidelity over a broad range of frequencies. The metasurface hologram features the combination of two sets of hologram patterns operating with opposite incident helicities. Two symmetrically distributed off-axis images are interchangeable by controlling the helicity of the input light. The demonstrated helicity multiplexed metasurface hologram with its high performance opens avenues for future applications with functionality switchable optical devices.

  9. Optical Interconnection Via Computer-Generated Holograms

    Liu, Hua-Kuang; Zhou, Shaomin

    1995-01-01

    Method of free-space optical interconnection developed for data-processing applications like parallel optical computing, neural-network computing, and switching in optical communication networks. In method, multiple optical connections between multiple sources of light in one array and multiple photodetectors in another array made via computer-generated holograms in electrically addressed spatial light modulators (ESLMs). Offers potential advantages of massive parallelism, high space-bandwidth product, high time-bandwidth product, low power consumption, low cross talk, and low time skew. Also offers advantage of programmability with flexibility of reconfiguration, including variation of strengths of optical connections in real time.

  10. Holograms for the Masses

    Newswanger, Craig; Klug, Michael

    2013-01-01

    Traditional holography subject matter has been generally limited to small dead things (SMD). Pulse lasers and the advent of holographic stereography have made it easier to make holograms of scaled objects and those that live (un-SMD), at a cost of single dimensional parallax or monochromaticity. While stunning results have been produced, all of these required access to a lab, expensive lasers and optics, and infinite patience, care and skill to collect and record content. This complexity has generally kept holography out of reach for the masses. The recent introduction of new 3D data sources, free or inexpensive composition and editing software, and fast, consistent print services may make it possible to finally 'democratize' holography, and enable image makers to focus on message rather than medium. This paper will outline several photogrammetry-based methods for producing 3D content for holograms (with a camera and mouse finger), software applications for editing, positioning and lighting, and production means that are usable by anyone, from novice to professional. We will present step-by-step examples and display results depicting various subject matter, from color holographic portraits made from smart phone input to holographic maps made from movies collected with remote control airplanes. The aim is to inspire image making, spontaneity, and maybe even social media-based collaboration to make EVERYONE a holographer.

  11. Hololujah; A One Kilometre Art Hologram

    Warren, David

    2013-02-01

    This paper will outline the production of the white light transmission achromatic image art hologram titled Hololujah displaying forward projecting real imagery of text and measuring 100,000 × 3.5 cm. Materials and methods: The paper will cover the use of Slavich VRP-M film 33.3 × 1.05 metres that was exposed and processed as thirty-three and a third 100 × 105 cm frames. These thirty-three and a third frames were subsequently cut into one thousand 100 × 3.5 cm strips with their ends cold laminated together to form the kilometre length hologram. This paper will expand on the use of a Coherent Compass 315M, 532 nm, 150 mW DPSS laser diode in a lensless setup, using a single beam through diffuse glass, no isolation systems and a two minute exposure time with the film lying flat on the floor. Lastly, this paper will illustrate how the hologram was produced in a 220 × 200 × 300 cm confined area of a suburban bedroom. Theme: This artwork is a comment on the social networking site Twitter.

  12. Electromagnetic reprogrammable coding-metasurface holograms.

    Li, Lianlin; Jun Cui, Tie; Ji, Wei; Liu, Shuo; Ding, Jun; Wan, Xiang; Bo Li, Yun; Jiang, Menghua; Qiu, Cheng-Wei; Zhang, Shuang

    2017-08-04

    Metasurfaces have enabled a plethora of emerging functions within an ultrathin dimension, paving way towards flat and highly integrated photonic devices. Despite the rapid progress in this area, simultaneous realization of reconfigurability, high efficiency, and full control over the phase and amplitude of scattered light is posing a great challenge. Here, we try to tackle this challenge by introducing the concept of a reprogrammable hologram based on 1-bit coding metasurfaces. The state of each unit cell of the coding metasurface can be switched between '1' and '0' by electrically controlling the loaded diodes. Our proof-of-concept experiments show that multiple desired holographic images can be realized in real time with only a single coding metasurface. The proposed reprogrammable hologram may be a key in enabling future intelligent devices with reconfigurable and programmable functionalities that may lead to advances in a variety of applications such as microscopy, display, security, data storage, and information processing.Realizing metasurfaces with reconfigurability, high efficiency, and control over phase and amplitude is a challenge. Here, Li et al. introduce a reprogrammable hologram based on a 1-bit coding metasurface, where the state of each unit cell of the coding metasurface can be switched electrically.

  13. Using Information on Exposure to Characterizing Risks to Human Health from Concurrent Exposures to Multiple Chemicals

    Mr Price, PSP

    2012-01-01

    This thesis explores the concept of using exposure information to understand, organize, and manage the risks associated with cumulative exposures to chemicals (exposures to multiple chemicals from multiple sources). The issue of cumulative exposures was identified in more than 30 years ago, but in

  14. Automatic decomposition of a complex hologram based on the virtual diffraction plane framework

    Jiao, A S M; Tsang, P W M; Lam, Y K; Poon, T-C; Liu, J-P; Lee, C-C

    2014-01-01

    Holography is a technique for capturing the hologram of a three-dimensional scene. In many applications, it is often pertinent to retain specific items of interest in the hologram, rather than retaining the full information, which may cause distraction in the analytical process that follows. For a real optical image that is captured with a camera or scanner, this process can be realized by applying image segmentation algorithms to decompose an image into its constituent entities. However, because it is different from an optical image, classic image segmentation methods cannot be applied directly to a hologram, as each pixel in the hologram carries holistic, rather than local, information of the object scene. In this paper, we propose a method to perform automatic decomposition of a complex hologram based on a recently proposed technique called the virtual diffraction plane (VDP) framework. Briefly, a complex hologram is back-propagated to a hypothetical plane known as the VDP. Next, the image on the VDP is automatically decomposed, through the use of the segmentation on the magnitude of the VDP image, into multiple sub-VDP images, each representing the diffracted waves of an isolated entity in the scene. Finally, each sub-VDP image is reverted back to a hologram. As such, a complex hologram can be decomposed into a plurality of subholograms, each representing a discrete object in the scene. We have demonstrated the successful performance of our proposed method by decomposing a complex hologram that is captured through the optical scanning holography (OSH) technique. (papers)

  15. Copying of holograms by spot scanning approach.

    Okui, Makoto; Wakunami, Koki; Oi, Ryutaro; Ichihashi, Yasuyuki; Jackin, Boaz Jessie; Yamamoto, Kenji

    2018-05-20

    To replicate holograms, contact copying has conventionally been used. In this approach, a photosensitive material is fixed together with a master hologram and illuminated with a coherent beam. This method is simple and enables high-quality copies; however, it requires a large optical setup for large-area holograms. In this paper, we present a new method of replicating holograms that uses a relatively compact optical system even for the replication of large holograms. A small laser spot that irradiates only part of the hologram is used to reproduce the hologram by scanning the spot over the whole area of the hologram. We report on the results of experiments carried out to confirm the copy quality, along with a guide to design scanning conditions. The results show the potential effectiveness of the large-area hologram replication technology using a relatively compact apparatus.

  16. Fast generation of Fresnel holograms based on multirate filtering.

    Tsang, Peter; Liu, Jung-Ping; Cheung, Wai-Keung; Poon, Ting-Chung

    2009-12-01

    One of the major problems in computer-generated holography is the high computation cost involved for the calculation of fringe patterns. Recently, the problem has been addressed by imposing a horizontal parallax only constraint whereby the process can be simplified to the computation of one-dimensional sublines, each representing a scan plane of the object scene. Subsequently the sublines can be expanded to a two-dimensional hologram through multiplication with a reference signal. Furthermore, economical hardware is available with which sublines can be generated in a computationally free manner with high throughput of approximately 100 M pixels/second. Apart from decreasing the computation loading, the sublines can be treated as intermediate data that can be compressed by simply downsampling the number of sublines. Despite these favorable features, the method is suitable only for the generation of white light (rainbow) holograms, and the resolution of the reconstructed image is inferior to the classical Fresnel hologram. We propose to generate holograms from one-dimensional sublines so that the above-mentioned problems can be alleviated. However, such an approach also leads to a substantial increase in computation loading. To overcome this problem we encapsulated the conversion of sublines to holograms as a multirate filtering process and implemented the latter by use of a fast Fourier transform. Evaluation reveals that, for holograms of moderate size, our method is capable of operating 40,000 times faster than the calculation of Fresnel holograms based on the precomputed table lookup method. Although there is no relative vertical parallax between object points at different distance planes, a global vertical parallax is preserved for the object scene as a whole and the reconstructed image can be observed easily.

  17. Resolution of holograms produced by the fluid experiment system and the holography ground system

    Brooks, Howard L.

    1987-01-01

    The Fluid Experiment System (FES) was developed to study low temperature crystal growth of triglycine sulfate from solution in a low gravity environment onboard Spacelab. The first flight of FES was in 1985. FES uses an optical system to take holograms of the growing crystal to be analyzed after the mission in the Holography Ground System (HGS) located in the Test Laboratory at Marshall Space Flight Center. Microscopic observation of the images formed by the reconstructed holograms is critical to determining crystal growth rate and particle velocity. FES and HGS were designed for a resolution of better than 20 micrometers, but initial observation of the flight holograms show a limit of 80 micrometers. The resolution of the FES holograms is investigated, as well as the role of beam intensity ratio and exposure time on the resolution of HGS produced holograms.

  18. Bronze rainbow hologram mirrors

    Dawson, P.

    2006-02-01

    This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

  19. Practical system for generating digital mixed reality video holograms.

    Song, Joongseok; Kim, Changseob; Park, Hanhoon; Park, Jong-Il

    2016-07-10

    We propose a practical system that can effectively mix the depth data of real and virtual objects by using a Z buffer and can quickly generate digital mixed reality video holograms by using multiple graphic processing units (GPUs). In an experiment, we verify that real objects and virtual objects can be merged naturally in free viewing angles, and the occlusion problem is well handled. Furthermore, we demonstrate that the proposed system can generate mixed reality video holograms at 7.6 frames per second. Finally, the system performance is objectively verified by users' subjective evaluations.

  20. Multiplexed Holograms by Surface Plasmon Propagation and Polarized Scattering.

    Chen, Ji; Li, Tao; Wang, Shuming; Zhu, Shining

    2017-08-09

    Thanks to the superiority in controlling the optical wave fronts, plasmonic nanostructures have led to various striking applications, among which metasurface holograms have been well developed and endowed with strong multiplexing capability. Here, we report a new design of multiplexed plasmonic hologram, which allows for reconstruction of multiple holographic images in free space by scatterings of surface plasmon polariton (SPP) waves in different propagation directions. Besides, the scattered polarization states can be further modulated by arranging the orientations of nanoscatterers. By incorporation of the SPP propagation and polarized scattering, a 4-fold hologram with low crosstalk is successfully demonstrated, which breaks the limitation of only two orthogonal states in conventional polarization multiplexers. Moreover, our design using the near-field SPP as reference wave holds the advantage for compact integration. This holographic approach is expected to inspire new photonic designs with enhanced information capacity and integratability.

  1. Metasurface holograms reaching 80% efficiency.

    Zheng, Guoxing; Mühlenbernd, Holger; Kenney, Mitchell; Li, Guixin; Zentgraf, Thomas; Zhang, Shuang

    2015-04-01

    Surfaces covered by ultrathin plasmonic structures--so-called metasurfaces--have recently been shown to be capable of completely controlling the phase of light, representing a new paradigm for the design of innovative optical elements such as ultrathin flat lenses, directional couplers for surface plasmon polaritons and wave plate vortex beam generation. Among the various types of metasurfaces, geometric metasurfaces, which consist of an array of plasmonic nanorods with spatially varying orientations, have shown superior phase control due to the geometric nature of their phase profile. Metasurfaces have recently been used to make computer-generated holograms, but the hologram efficiency remained too low at visible wavelengths for practical purposes. Here, we report the design and realization of a geometric metasurface hologram reaching diffraction efficiencies of 80% at 825 nm and a broad bandwidth between 630 nm and 1,050 nm. The 16-level-phase computer-generated hologram demonstrated here combines the advantages of a geometric metasurface for the superior control of the phase profile and of reflectarrays for achieving high polarization conversion efficiency. Specifically, the design of the hologram integrates a ground metal plane with a geometric metasurface that enhances the conversion efficiency between the two circular polarization states, leading to high diffraction efficiency without complicating the fabrication process. Because of these advantages, our strategy could be viable for various practical holographic applications.

  2. Generation of binary holograms for deep scenes captured with a camera and a depth sensor

    Leportier, Thibault; Park, Min-Chul

    2017-01-01

    This work presents binary hologram generation from images of a real object acquired from a Kinect sensor. Since hologram calculation from a point-cloud or polygon model presents a heavy computational burden, we adopted a depth-layer approach to generate the holograms. This method enables us to obtain holographic data of large scenes quickly. Our investigations focus on the performance of different methods, iterative and noniterative, to convert complex holograms into binary format. Comparisons were performed to examine the reconstruction of the binary holograms at different depths. We also propose to modify the direct binary search algorithm to take into account several reference image planes. Then, deep scenes featuring multiple planes of interest can be reconstructed with better efficiency.

  3. Averaging scheme for atomic resolution off-axis electron holograms.

    Niermann, T; Lehmann, M

    2014-08-01

    All micrographs are limited by shot-noise, which is intrinsic to the detection process of electrons. For beam insensitive specimen this limitation can in principle easily be circumvented by prolonged exposure times. However, in the high-resolution regime several instrumental instabilities limit the applicable exposure time. Particularly in the case of off-axis holography the holograms are highly sensitive to the position and voltage of the electron-optical biprism. We present a novel reconstruction algorithm to average series of off-axis holograms while compensating for specimen drift, biprism drift, drift of biprism voltage, and drift of defocus, which all might cause problematic changes from exposure to exposure. We show an application of the algorithm utilizing also the possibilities of double biprism holography, which results in a high quality exit-wave reconstruction with 75 pm resolution at a very high signal-to-noise ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. FEATURES OF MULTIPLEXED HOLOGRAMS RECORDING IN PHOTO-THERMO-REFRACTIVE GLASS

    S. A. Ivanov

    2016-05-01

    Full Text Available We have carried out calculations of recording conditions for multiplexed holograms in photo-thermo-refractive (PTR glass. The proposed calculation sets the link between such parameters as: the angle between recording beams and the angle of sample rotation, operating wavelength, the angle of incidence on the element, output angle. To study recording features of multiplexed holograms on PTR glass several elements was made. Six holograms in each element were recorded with various exposures. All samples were heat-treated at one temperature around glass transition temperature. It has been demonstrated that at the recording of several gratings with a total exposure exceeding an optimal value for a given material, the total value of the refractive index modulation amplitude (n1 reaches the maximum attainable magnitude that is equivalent to a value of a single hologram with optimal exposure. It has been found that refractive index dynamic range of the material distributes between the gratings in accordance with the ratio between exposure times if holograms exposures have significant differences. In the present paper six-channel multiplexer was recorded for a wavelength equal to 632.8 nm (He-Ne laser. The diffraction angles correspond to calculations mentioned above. The n1 value in each grating is equal to the value of the highest attainable value of the value of n1 divided by the total number of multiplexed holograms.

  5. Silver-halide sensitized gelatin (SHSG) processing method for pulse holograms recorded on VRP plates

    Evstigneeva, Maria K.; Drozdova, Olga V.; Mikhailov, Viktor N.

    2002-06-01

    One of the most important area of holograph applications is display holography. In case of pulse recording the requirement for vibration stability is easier than compared to CW exposure. At the same time it is widely known that the behavior of sliver-halide holographic materials strongly depends on the exposure duration. In particular the exposure sensitivity drastically decreases under nanosecond pulse duration. One of the effective ways of the diffraction efficiency improvement is SHSG processing method. This processing scheme is based on high modulation of refractive index due to microvoids appearance inside emulsion layer. It should be mentioned that the SHSG method was used earlier only in the cases when the holograms were recorded by use of CW lasers. This work is devoted to the investigation of SHSG method for pulse hologram recording on VRP plates. We used a pulsed YLF:Nd laser with pulse duration of 25 nanoseconds and wavelength of 527 nm. Both transmission and reflection holograms were recorded. The different kinds of bleaching as well as developing solutions were investigated. Our final processing scheme includes the following stages: 1) development in non-tanning solution, 2) rehalogenating bleach, 3) intermediate alcohol drying, 4) uniform second exposure, 5) second development in diluted developer, 6) reverse bleaching, 7) fixing and 8) gradient drying in isopropyl alcohol. Diffraction efficiency of transmission holograms was of about 60 percent and reflection mirror holograms was of about 45 percent. Thus we have demonstrated the SHSG processing scheme for producing effective holograms on VRP plates under pulse exposure.

  6. Photo-polymer for recording holograms

    Hideo Tanigawa; Taichi Ichihashi; Takashi Matsuo

    1999-01-01

    The photo-polymerizable materials for recording holograms were composed of higher-index polymers, lower-index monomers, and photo-initiators. The materials have sensitivity from UV green light (514.5 nm ). The diffraction efficiencies of the transmission holograms recorded by two beams from a laser were more than 80%. These holograms have good physical and chemical stability. The mechanisms of the formation of holograms was discussed. In this paper, experimental results for transmission holograms are reported and the mechanisms of refractive index modulation in photo-polymerization of the materials are discussed

  7. Exposure to Multiple Languages Enhances Communication Skills in Infancy

    Liberman, Zoe; Woodward, Amanda L.; Keysar, Boaz; Kinzler, Katherine D.

    2017-01-01

    Early exposure to multiple languages can enhance children's communication skills, even when children are effectively monolingual (Fan, Liberman, Keysar & Kinzler, 2015). Here we report evidence that the social benefits of multilingual exposure emerge in infancy. Sixteen-month-old infants participated in a communication task that required…

  8. Unraveling light with digital holograms

    Forbes, A

    2013-02-01

    Full Text Available devices, digital holography as an enabling tool has become accessible to all, and with it modal decomposition has come of age. Here we outline the basic principles of modal decomposition of laser beams with digital holograms, and review recent results...

  9. Agricultural Exposures, Multiple Myeloma Etiology: Profile of Jonathan Hofmann

    Tenure-track investigator Jonathan Hofmann, Ph.D., M.P.H., has established a research program in the Occupational and Environmental Epidemiology Branch focused on the role of agricultural exposures in the etiology of multiple myeloma and other cancers, and on understanding the biological mechanisms that influence the development and progression of multiple myeloma.

  10. The hologram as a space of illusion

    Oliveira, Rosa M.

    2013-03-01

    One of the most interesting aspects of art holography is the study of 3D holographic image. Over the centuries, artists have chased the best way to represent the third dimension as similar to reality as possible. Several steps have been given in this direction, first using perspective, then photography, and later with movies, but all of these representations of reality wouldn't reach the complete objective. The realism of a 3D representation on a 2D support (paper, canvas, celluloid) is completely overcome by holography. In spite of the fact that the holographic plate or film is also a 2D support, the holographic image is a recording of all the information of the object contained in light. Our perception doesn't need to translate the object as real. It is real. Though immaterial, the holographic image is real because it exists in light. The same parallax, the same shape. The representation is no more an imitation of reality but a replacement of the real object or scene. The space where it exists is a space of illusion and multiple objects can occupy the same place in the hologram, depending on the viewer's time and place. This introduces the fourth dimension in the hologram: time, as well as the apparent conflict between the presence and the absence of images, which is just possible in holography.

  11. Holograms and authentication: meeting future demands

    Lancaster, Ian M.

    2004-06-01

    The use of holograms as authentication or security devices is the most valuable application of holograms yet devised. In 20 years, this has developed from the first use of a hologram on credit cards, to the situation today where governments turn to holograms as a key security feature on the protected documents they issue, including banknotes, identity documents and tax banderols. At the same time, holograms (and related devices) are the most recognised visible feature used to authenticate and protect branded and OEM products; this sector covers the gamut from CD jewel-box seals to the protection of safety-related items such as medicines and vehicle replacement parts. There has been creative synergy between the commercial suppliers of such holograms and the practical holography community. But new technologies are coming forward to challenge the role of holograms, a challenge that is aided by the counterfeiting of security holograms. What are the characteristics of those technologies and can holograms provide similar resources to users? Examples of collaboration between hologram producers and producers of other technologies to create combination devices suggest a possible route forward for holography to maintain its role in authentication and security. By scrutinising and adapting to needs, often by combination with other techniques, holographers may be able to retain their role in this important application.

  12. Multiple context mere exposure: Examining the limits of liking.

    de Zilva, Daniel; Newell, Ben R; Mitchell, Chris J

    2016-01-01

    Recent evidence suggests that increased liking of exposed stimuli-a phenomenon known as the mere exposure effect-is dependent on experiencing the stimuli in the same context at exposure and test. Three experiments extended this work by examining the effect of presenting target stimuli in single and multiple exposure contexts. Target face stimuli were repeatedly paired with nonsense words, which took the role of contexts, across exposure. On test, the mere exposure effect was found only when the target face stimuli were presented with nonsense word cues (contexts) with which they had been repeatedly paired. The mere exposure effect was eliminated when exposure to target face stimuli with the nonsense word cues (contexts) was minimal, despite the overall number of exposures to the target face being equated across single- and multiple-context exposure conditions. The results suggest that familiarity of the relationship between stimuli and their context, not simply familiarity of the stimuli themselves, leads to liking. The finding supports a broader framework, which suggests that liking is partly a function of the consistency between past and present experiences with a target stimulus.

  13. New coding technique for computer generated holograms.

    Haskell, R. E.; Culver, B. C.

    1972-01-01

    A coding technique is developed for recording computer generated holograms on a computer controlled CRT in which each resolution cell contains two beam spots of equal size and equal intensity. This provides a binary hologram in which only the position of the two dots is varied from cell to cell. The amplitude associated with each resolution cell is controlled by selectively diffracting unwanted light into a higher diffraction order. The recording of the holograms is fast and simple.

  14. Accelerated numerical processing of electronically recorded holograms with reduced speckle noise.

    Trujillo, Carlos; Garcia-Sucerquia, Jorge

    2013-09-01

    The numerical reconstruction of digitally recorded holograms suffers from speckle noise. An accelerated method that uses general-purpose computing in graphics processing units to reduce that noise is shown. The proposed methodology utilizes parallelized algorithms to record, reconstruct, and superimpose multiple uncorrelated holograms of a static scene. For the best tradeoff between reduction of the speckle noise and processing time, the method records, reconstructs, and superimposes six holograms of 1024 × 1024 pixels in 68 ms; for this case, the methodology reduces the speckle noise by 58% compared with that exhibited by a single hologram. The fully parallelized method running on a commodity graphics processing unit is one order of magnitude faster than the same technique implemented on a regular CPU using its multithreading capabilities. Experimental results are shown to validate the proposal.

  15. Holograms made with a pulsed dye laser

    Fernandez-Guasti, M.; Iturbe-Castillo, D.; Silva-Perez, A.; Gil-Villegas, A.; Gonzalez-Torres, H.; Lopez-Guerrero, R.

    1989-01-01

    We report the obtention of holograms with a nitrogen pumped dye laser, whose source is inherently pulsed. We review the advantages and posibilities of holograms of moving objects which are impossible to make with CW lasers. The lasers used in these experiments were designed and built in the quantum optics laboratory at the Universidad Autonoma Metropolitana-Iztapalapa. (Author)

  16. Full-Color Plasmonic Metasurface Holograms.

    Wan, Weiwei; Gao, Jie; Yang, Xiaodong

    2016-12-27

    Holography is one of the most attractive approaches for reconstructing optical images, due to its capability of recording both the amplitude and phase information on light scattered from objects. Recently, optical metasurfaces for manipulating the wavefront of light with well-controlled amplitude, phase, and polarization have been utilized to reproduce computer-generated holograms. However, the currently available metasurface holograms have only been designed to achieve limited colors and record either amplitude or phase information. This fact significantly limits the performance of metasurface holograms to reconstruct full-color images with low noise and high quality. Here, we report the design and realization of ultrathin plasmonic metasurface holograms made of subwavelength nanoslits for reconstructing both two- and three-dimensional full-color holographic images. The wavelength-multiplexed metasurface holograms with both amplitude and phase modulations at subwavelength scale can faithfully produce not only three primary colors but also their secondary colors. Our results will advance various holographic applications.

  17. Temperature changes across porcelain during multiple exposure CO2 lasing

    Barron, Joseph R.; Zakariasen, Kenneth L.; Peacocke, Larry

    1990-06-01

    Research indicates that laser energy may provide a useful method for glazing and fusing porcelain for intraoral prosthetic purposes. However, it is not known whether such lasing will result in the production of heat levels that may be damaging to adjacent vital tissues such as the dental pulp and periodontal tissues. This research is designed to measure the magnitude of temperature rise across porcelain observed during multiple exposure C02 lasing. Fifteen porcelain examples of 1000 jim (5), 1500 pm (5) and 2000 tm (5) x each received five C02 laser exposures on the same exposure site at 1.0 sec. intervals at 8.0 watts (0.2 sec. per exposure with a 1 mm focal spot). A YSI 144201 thermilinear precision thermistor was placed on the porcelain surface opposite each laser exposure site. Temperature rise above ambient was recorded by an HP3421A data acquisition unit and HP9816 technical microcomputer. Recording continued for sufficient time to allow temperatures to return to ambient. The mean temperature elevations ranged from a low of 2.97 0C (2000 pm) to a high of 7.77 °C (1000 μm). ANOVA and Duncan's Multiple Range Test indicated significant differences in temperature rise by porcelain thickness. It would appear from the results of this research that temperature elevations adjacent to lased porcelain may be sufficiently controllable that safe intraoral porcelain lasing will be possible.

  18. An efficient multiple exposure image fusion in JPEG domain

    Hebbalaguppe, Ramya; Kakarala, Ramakrishna

    2012-01-01

    In this paper, we describe a method to fuse multiple images taken with varying exposure times in the JPEG domain. The proposed algorithm finds its application in HDR image acquisition and image stabilization for hand-held devices like mobile phones, music players with cameras, digital cameras etc. Image acquisition at low light typically results in blurry and noisy images for hand-held camera's. Altering camera settings like ISO sensitivity, exposure times and aperture for low light image capture results in noise amplification, motion blur and reduction of depth-of-field respectively. The purpose of fusing multiple exposures is to combine the sharp details of the shorter exposure images with high signal-to-noise-ratio (SNR) of the longer exposure images. The algorithm requires only a single pass over all images, making it efficient. It comprises of - sigmoidal boosting of shorter exposed images, image fusion, artifact removal and saturation detection. Algorithm does not need more memory than a single JPEG macro block to be kept in memory making it feasible to be implemented as the part of a digital cameras hardware image processing engine. The Artifact removal step reuses the JPEGs built-in frequency analysis and hence benefits from the considerable optimization and design experience that is available for JPEG.

  19. Application of photopolymer holograms for the anticounterfeit protection of banknotes

    Markova, Nina V.; Yamnikov, Leonid S.; Turkina, Elena S.; Semenov, Erick G.; Bulygin, Theodor V.; Levin, Gennady G.

    1998-04-01

    The article analyses holograms counterfeiting techniques and presents grounds for the choice of the optimum type of holograms best protected against counterfeiting -- volume holograms. There is a description of these holograms registration process on DuPont OmniDex photopolymer film and the analysis of the perspective of their use during banknotes production.

  20. Fast calculation method for computer-generated cylindrical holograms.

    Yamaguchi, Takeshi; Fujii, Tomohiko; Yoshikawa, Hiroshi

    2008-07-01

    Since a general flat hologram has a limited viewable area, we usually cannot see the other side of a reconstructed object. There are some holograms that can solve this problem. A cylindrical hologram is well known to be viewable in 360 deg. Most cylindrical holograms are optical holograms, but there are few reports of computer-generated cylindrical holograms. The lack of computer-generated cylindrical holograms is because the spatial resolution of output devices is not great enough; therefore, we have to make a large hologram or use a small object to fulfill the sampling theorem. In addition, in calculating the large fringe, the calculation amount increases in proportion to the hologram size. Therefore, we propose what we believe to be a new calculation method for fast calculation. Then, we print these fringes with our prototype fringe printer. As a result, we obtain a good reconstructed image from a computer-generated cylindrical hologram.

  1. Double-pass quantum volume hologram

    Vasilyev, Denis V.; Sokolov, Ivan V.

    2011-01-01

    We propose a scheme for parallel, spatially multimode quantum memory for light. The scheme is based on the propagation in different directions of a quantum signal wave and strong classical reference wave, like in a classical volume hologram and the previously proposed quantum volume hologram [D. V. Vasilyev et al., Phys. Rev. A 81, 020302(R) (2010)]. The medium for the hologram consists of a spatially extended ensemble of cold spin-polarized atoms. In the absence of the collective spin rotation during the interaction, two passes of light for both storage and retrieval are required, and therefore the present scheme can be called a double-pass quantum volume hologram. The scheme is less sensitive to diffraction and therefore is capable of achieving a higher density of storage of spatial modes as compared to the previously proposed thin quantum hologram [D. V. Vasilyev et al., Phys. Rev. A 77, 020302(R) (2008)], which also requires two passes of light for both storage and retrieval. However, the present scheme allows one to achieve a good memory performance with a lower optical depth of the atomic sample as compared to the quantum volume hologram. A quantum hologram capable of storing entangled images can become an important ingredient in quantum information processing and quantum imaging.

  2. Temperature changes across CO2-lased dentin during multiple exposures

    Zakariasen, Kenneth L.; Barron, Joseph R.; Boran, Thomas L.

    1990-06-01

    The literature increasingly indicates that lasers will have a multitude of applications for dental hard tissue procedures, e.g. preventive therapy, caries removal, laser etching and endodontic therapy. However, it is critical that such laser therapies avoid the production of heat levels which will be damaging to the surrounding vital tissues, such as the dental pulp and periodontal tissues. Our preliminary research on temperature changes across C02 lased dentin indicated that for single preventive therapeutic exposures (1.2 W., 0. 1 sec., 1.0 mm focal spot) the mean temperature rise across 350 j.tm of dentin was 0.57 0C while across 1000 .tm of dentin the mean rise was only 0.18 °C. Further research utilizing multiple preventive therapeutic exposures (1.2 W., 0. 1 sec., 1.0 mm focal spot, 3 x 1.0 sec. intervals) showed mean temperature elevations of 1.56 0C across 350 m of dentin and 0.66 O across 1000 xm of dentin. While these temperature elevations, which would be associated with preventive therapy, are very low and would be biologically acceptable, it must be noted that exposures of higher intensities are required to fuse enamel and porcelain, or remove decay. This current research investigates temperature elevations which occuT during C02 lasing utilizing the following exposure parameters: 8.0 W., 1.0 mm focal spot, 0.1 sec. exposures, 2 or 4 exposures per site pulsed 1.0 sec. apart. Three dentin thicknesses were utilized, i.e. 1000 jim, 1500 p.tm and 2000 .tm. Four sections of each thickness were utilized with four exposure sites per specimen (2 with 2 exposures, 2 with 4 exposures). All dentin sections were prepared from non-carious third molars using a hard tissue microtome. A thermistor was placed on the dentin surface opposite each lased site and temperature changes were recorded for approximately 50 sec. following lasing. Mean temperature elevations ranged from a high of 3.07 C for the 1000 xm section utilizing four exposures to a low of 0.37 0C for the

  3. Reflection-type hologram for atoms

    Shimizu, Fujio; Fujita, Jun-ichi

    2002-01-01

    A cold metastable neon atomic beam was manipulated with a reflective amplitude hologram that was encoded on a silicon surface. A black-and-white pattern of atoms was reconstructed on a microchannel plate detector. The hologram used the enhanced quantum reflection developed by authors and was made of a two-dimensional array of rectangular low and high reflective cells. The surface of the high reflective cell was composed of regularly spaced roof-shaped ridges, while the low reflective cell was simply a flat surface. The hologram was the first demonstration of reflective atom-optical elements that used universal interaction between a neutral atom and solid surface

  4. Two schemes for rapid generation of digital video holograms using PC cluster

    Park, Hanhoon; Song, Joongseok; Kim, Changseob; Park, Jong-Il

    2017-12-01

    Computer-generated holography (CGH), which is a process of generating digital holograms, is computationally expensive. Recently, several methods/systems of parallelizing the process using graphic processing units (GPUs) have been proposed. Indeed, use of multiple GPUs or a personal computer (PC) cluster (each PC with GPUs) enabled great improvements in the process speed. However, extant literature has less often explored systems involving rapid generation of multiple digital holograms and specialized systems for rapid generation of a digital video hologram. This study proposes a system that uses a PC cluster and is able to more efficiently generate a video hologram. The proposed system is designed to simultaneously generate multiple frames and accelerate the generation by parallelizing the CGH computations across a number of frames, as opposed to separately generating each individual frame while parallelizing the CGH computations within each frame. The proposed system also enables the subprocesses for generating each frame to execute in parallel through multithreading. With these two schemes, the proposed system significantly reduced the data communication time for generating a digital hologram when compared with that of the state-of-the-art system.

  5. Acoustic holograms of active regions

    Chou, Dean-Yi

    2008-01-01

    We propose a method to study solar magnetic regions in the solar interior with the principle of optical holography. A magnetic region in the solar interior scatters the solar background acoustic waves. The scattered waves and background waves could form an interference pattern on the solar surface. We investigate the feasibility of detecting this interference pattern on the solar surface, and using it to construct the three-dimensional scattered wave from the magnetic region with the principle of optical holography. In solar acoustic holography, the background acoustic waves play the role of reference wave; the magnetic region plays the role of the target object; the interference pattern, acoustic power map, on the solar surface plays the role of the hologram.

  6. Acoustic holograms of active regions

    Chou, Dean-Yi [Physics Department, National Tsing Hua University, Hsinchu, 30013, Taiwan (China)], E-mail: chou@phys.nthu.edu.tw

    2008-10-15

    We propose a method to study solar magnetic regions in the solar interior with the principle of optical holography. A magnetic region in the solar interior scatters the solar background acoustic waves. The scattered waves and background waves could form an interference pattern on the solar surface. We investigate the feasibility of detecting this interference pattern on the solar surface, and using it to construct the three-dimensional scattered wave from the magnetic region with the principle of optical holography. In solar acoustic holography, the background acoustic waves play the role of reference wave; the magnetic region plays the role of the target object; the interference pattern, acoustic power map, on the solar surface plays the role of the hologram.

  7. Toxicity assessment of unintentional exposure to multiple chemicals

    Mumtaz, M.M.; Ruiz, P.; De Rosa, C.T.

    2007-01-01

    Typically exposure to environmental chemicals is unintentional, and often the exposure is to chemical mixtures, either simultaneously or sequentially. When exposure occurs, in public health practice, it is prudent to ascertain if thresholds for harmful health effects are exceeded, whether by individual chemicals or by chemicals in combination. Three alternative approaches are available for assessing the toxicity of chemical mixtures. Each approach, however, has shortcomings. As the procedures of each approach are described in this paper, at various steps research needs are identified. Recently, reliance has increased on computational toxicology methods for predicting toxicological effects when data are limited. Advances in molecular biology, identification of biomarkers, and availability of accurate and sensitive methods allow us to more precisely define the relationships between multiple chemical exposures and health effects, both qualitatively and quantitatively. Key research needs are best fulfilled through collaborative research. It is through such collaborations that resources are most effectively leveraged to further develop and apply toxicity assessment methods that advance public health practices in vulnerable communities

  8. Quantum memory for images: A quantum hologram

    Vasilyev, Denis V.; Sokolov, Ivan V.; Polzik, Eugene S.

    2008-01-01

    Matter-light quantum interface and quantum memory for light are important ingredients of quantum information protocols, such as quantum networks, distributed quantum computation, etc. [P. Zoller et al., Eur. Phys. J. D 36, 203 (2005)]. In this paper we present a spatially multimode scheme for quantum memory for light, which we call a quantum hologram. Our approach uses a multiatom ensemble which has been shown to be efficient for a single spatial mode quantum memory. Due to the multiatom nature of the ensemble and to the optical parallelism it is capable of storing many spatial modes, a feature critical for the present proposal. A quantum hologram with the fidelity exceeding that of classical hologram will be able to store quantum features of an image, such as multimode superposition and entangled quantum states, something that a standard hologram is unable to achieve

  9. Holograms preparation using commercial fluorescent benzyl

    Dorantes-GarcIa, V; Olivares-Perez, A; Ordonez-Padilla, M J; Mejias-Brizuela, N Y, E-mail: valdoga@Hotmail.com, E-mail: olivares@inaoep.mx [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Coordinacion de Optica, Calle Luis Enrique Erro N0 1, Santa Maria Tonantzintla, Puebla (Mexico)

    2011-01-01

    We have been able to make holograms with substances such as fluorescence thought of light blue laser to make transmissions holograms, using ammonium dichromate as photo-sensitizer and polyvinyl alcohol (PVA) as matrix. Ammonium dichromate inhibit the fluorescence properties of inks, both mixed in a (PVA) matrix, but we avoid this chemical reaction and we show the results to use the method of painting hologram with fluorescents ink and we describe how the diffraction efficiency parameter changes as a function of the ink absorbed by the emulsion recorded with the gratings, we got good results, making holographic gratings with a blue light from laser diode 470 nm. And we later were painting with fluorescent ink, integrating fluorescence characteristics to the hologram.

  10. Improvement in recording and reading holograms

    Hallock, J. N.

    1968-01-01

    Three-beam technique superimposes a number of patterns in the same plane of a hologram and then uniquely identifies each pattern by a suitable readout process. The developed readout process does not require any movement of parts.

  11. Rotational control of computer generated holograms.

    Preece, Daryl; Rubinsztein-Dunlop, Halina

    2017-11-15

    We develop a basis for three-dimensional rotation of arbitrary light fields created by computer generated holograms. By adding an extra phase function into the kinoform, any light field or holographic image can be tilted in the focal plane with minimized distortion. We present two different approaches to rotate an arbitrary hologram: the Scheimpflug method and a novel coordinate transformation method. Experimental results are presented to demonstrate the validity of both proposed methods.

  12. Making Displaced Holograms At Two Wavelengths

    Witherow, William K.; Ecker, Andreas

    1989-01-01

    Two-wavelength holographic system augmented with pair of prisms to introduce small separation between holograms formed simultaneously at two wavelengths on holographic plate. Principal use in study of flows. Gradients in index of refraction of fluid caused by variations in temperature, concentration, or both. Holography at one wavelength cannot be used to distinguish between two types of variations. Difference between spacings of fringes in photographs reconstructed from holograms taken simultaneously at two different wavelengths manipulated mathematically to determine type of variation.

  13. Enhancement of the measurement sensitivity at large aberrations of an optical system of hologram recording

    Lyalikov, A.M.

    1994-01-01

    The method of the measurement sensitivity enhancement with compensation of aberrations based on rewriting object and master holograms recorded on one common carrier using the double-exposure method is considered. Experimental studies indicated the proposed technique of the enhancement of the measurement sensitivity to be promising in the case of large aberrations of an optical system for initial hologram recording. The reconstructed interferograms are presented with enhanced sensitivity of measurements by a factor of 16 characterizing the quality of exit windows of a glass cuvette. 16 refs., 3 figs

  14. Lyssavirus infection: 'low dose, multiple exposure' in the mouse model.

    Banyard, Ashley C; Healy, Derek M; Brookes, Sharon M; Voller, Katja; Hicks, Daniel J; Núñez, Alejandro; Fooks, Anthony R

    2014-03-06

    quaternary inoculations although the serological response did not necessarily reflect the repeated exposure. We conclude that despite repeated exposure, neither clinical disease nor serological response can be predicted and that further studies are required to understand the mechanisms behind survival following multiple exposures to lyssaviruses. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  15. Bit-mapped Holograms Using Phase Transition Mastering (PTM) and Blu-ray Disks

    Barnhart, Donald

    2013-01-01

    Due to recent advances made in data storage, cloud computing, and Blu-ray mastering technology, it is now straight forward to calculate, store, transfer, and print bitmapped holograms that use terabytes of data and tera-pixels of information. This presentation reports on the potential of using the phase transition mastering (PTM) process to construct bitmapped, computer generated holograms with spatial resolutions of 5000 line-pairs/mm (70 nm pixel width). In particular, for Blu-ray disk production, Sony has developed a complete process that could be alternately deployed in holographic applications. The PTM process uses a 405 nm laser to write phase patterns onto a layer of imperfect transition metal oxides that is deposited onto an 8 inch silicon wafer. After the master hologram has been constructed, its imprint can then be cheaply mass produced with the same process as Blu-ray disks or embossed holograms. Unlike traditional binary holograms made with expensive e-beam lithography, the PTM process has the potential for multiple phase levels using inexpensive optics similar to consumer-grade desktop Blu-ray writers. This PTM process could revolutionise holography for entertainment, industrial, and scientific applications.

  16. Bit-mapped Holograms Using Phase Transition Mastering (PTM) and Blu-ray Disks

    Barnhart, Donald

    2013-02-01

    Due to recent advances made in data storage, cloud computing, and Blu-ray mastering technology, it is now straight forward to calculate, store, transfer, and print bitmapped holograms that use terabytes of data and tera-pixels of information. This presentation reports on the potential of using the phase transition mastering (PTM) process to construct bitmapped, computer generated holograms with spatial resolutions of 5000 line-pairs/mm (70 nm pixel width). In particular, for Blu-ray disk production, Sony has developed a complete process that could be alternately deployed in holographic applications. The PTM process uses a 405 nm laser to write phase patterns onto a layer of imperfect transition metal oxides that is deposited onto an 8 inch silicon wafer. After the master hologram has been constructed, its imprint can then be cheaply mass produced with the same process as Blu-ray disks or embossed holograms. Unlike traditional binary holograms made with expensive e-beam lithography, the PTM process has the potential for multiple phase levels using inexpensive optics similar to consumer-grade desktop Blu-ray writers. This PTM process could revolutionise holography for entertainment, industrial, and scientific applications.

  17. Application of up-sampling and resolution scaling to Fresnel reconstruction of digital holograms.

    Williams, Logan A; Nehmetallah, Georges; Aylo, Rola; Banerjee, Partha P

    2015-02-20

    Fresnel transform implementation methods using numerical preprocessing techniques are investigated in this paper. First, it is shown that up-sampling dramatically reduces the minimum reconstruction distance requirements and allows maximal signal recovery by eliminating aliasing artifacts which typically occur at distances much less than the Rayleigh range of the object. Second, zero-padding is employed to arbitrarily scale numerical resolution for the purpose of resolution matching multiple holograms, where each hologram is recorded using dissimilar geometric or illumination parameters. Such preprocessing yields numerical resolution scaling at any distance. Both techniques are extensively illustrated using experimental results.

  18. Control of broadband optically generated ultrasound pulses using binary amplitude holograms.

    Brown, Michael D; Jaros, Jiri; Cox, Ben T; Treeby, Bradley E

    2016-04-01

    In this work, the use of binary amplitude holography is investigated as a mechanism to focus broadband acoustic pulses generated by high peak-power pulsed lasers. Two algorithms are described for the calculation of the binary holograms; one using ray-tracing, and one using an optimization based on direct binary search. It is shown using numerical simulations that when a binary amplitude hologram is excited by a train of laser pulses at its design frequency, the acoustic field can be focused at a pre-determined distribution of points, including single and multiple focal points, and line and square foci. The numerical results are validated by acoustic field measurements from binary amplitude holograms, excited by a high peak-power laser.

  19. A generalized approach to computer synthesis of digital holograms

    Hopper, W. A.

    1973-01-01

    Hologram is constructed by taking number of digitized sample points and blending them together to form ''continuous'' picture. New system selects better set of sample points resulting in improved hologram from same amount of information.

  20. Synthesis of optical holograms of rotating objects

    Bogdanova, T.V.; Titar', V.P.; Tomchuk, E.Ya.

    1998-01-01

    A method of synthesis of rotating objects is analyzed and its advantages over the previously known methods and restrictions caused by the nonlinear character of motion of objects being studied are determined. Numerical simulation is used to study properties of synthesized holograms and the images reconstructed with their help. The resolving power of synthesized holograms is determined. The pulsed response of the system used for the synthesis of rotating objects is studied and its isoplanar sections are determined. It is shown that in the optical range, in contrast to the radio-frequency range, one can synthesize holograms and reconstruct visual images not only of rotating objects, but of vibrating objects as well. For small angles of object rotation (0.0025 rad), an image with a high resolution power (0.0004 m) can be obtained

  1. Synthesizing monochromatic 3-D images by multiple-exposure rainbow holography with vertical area-partition approach

    翟宏琛; 王明伟; 刘福民; 母国光

    2002-01-01

    We report for the first time the theoretical analysis and experimental results of a white-light reconstructed monochromatic 3-D image synthesizing tomograms by multiple rainbow holo-graphy with vertical-area partition (VAP) approach. The theoretical and experimental results show that 3-D monochromatic image can be synthesized by recording the master hologram by VAP ap-proach without any distortions either in gray scale or in geometrical position. A 3-D monochromatic image synthesized from a series of medical tomograms is presented in this paper for the first time.

  2. SEARCH AUTOMATION OF BINARIZATION OPTIMUM LEVEL FOR SYNTHESIZED HOLOGRAMS

    Oleg V. Nikanorov

    2017-11-01

    Full Text Available The paper considers the features of synthesized holograms suitable for practical use. It is established that binary holograms are the first of all suitable ones for successful application in practice. In order to select the most suitable (optimal level of hologram binarization, we propose a criterion for estimating the quality of an image reconstructed with a binary hologram. An algorithm is developed to find the optimal level. On the basis of the conducted experiments it is established that the introduction of the developed module gives the possibility to reduce the search time of the optimal binarization level of the hologram by eleven times in comparison with manual search.

  3. Femtosecond recording of holograms and hologram-like structures in volume recording media

    Dement'ev, D A; Kompanets, V O; Matveets, Yu A; Serov, O B; Chekalin, Sergei V; Smolovich, A M

    2001-01-01

    Reflection holograms in thick layers of bichromated gelatin are recorded by using 50-fs pulses of the second harmonic of a Ti:sapphire laser. (laser applications and other topics in quantum electronics)

  4. Assessment of multiple frequency ELF electric and magnetic field exposure

    Leitgeb, N

    2008-01-01

    Electromagnetic fields both in daily life and at workplaces exhibit increasingly complex frequency spectra. Present spectral assessment rules proved to be too conservative for health risk assessment. This is because they are based on the assumption that cells would react like linear systems in terms of responding to a sum of frequencies by a sum of independent responses to each individual frequency. Based on numerical investigations with the Hodgkin-Huxley and the Frankenhaeuser-Huxley nerve cell models, it could be shown that accounting for the nonlinear behaviour of cellular excitation processes avoids considerable overestimation of simultaneous exposures to multiple frequency ELF electric and magnetic fields. Besides this, it could be shown that the role of phase relationships is less important than that assumed so far. The present assessment rules lead to non-compliances of marketed electric appliances. For general application, a nonlinear biology-based assessment (NBBA) rule has been proposed, validated and proven advantageous compared with ICNIRP's rule. While staying conservative it avoids unnecessary overestimation and demonstrates compliance even in cases of suspected non-conformities. It is up to responsible bodies to decide upon the adoption of this proposal and the potential need for implementing additional or reducing the already incorporated safety factors

  5. Converting optical scanning holograms of real objects to binary Fourier holograms using an iterative direct binary search algorithm.

    Leportier, Thibault; Park, Min Chul; Kim, You Seok; Kim, Taegeun

    2015-02-09

    In this paper, we present a three-dimensional holographic imaging system. The proposed approach records a complex hologram of a real object using optical scanning holography, converts the complex form to binary data, and then reconstructs the recorded hologram using a spatial light modulator (SLM). The conversion from the recorded hologram to a binary hologram is achieved using a direct binary search algorithm. We present experimental results that verify the efficacy of our approach. To the best of our knowledge, this is the first time that a hologram of a real object has been reconstructed using a binary SLM.

  6. Laser beam characterization with digital holograms

    Forbes, A

    2013-04-01

    Full Text Available We show how laser beam characterization may be done in real-time with digital holograms. We illustrate the power of the techniques by applying them to a variety of laser sources, from fibers to solid-state....

  7. Environmental conditions influence for real-time hologram formation on dichromated polyvinyl alcohol NiCl2·6H2O doped films

    Fontanilla-Urdaneta, R C; Olivares-Perez, A; Fuentes-Tapia, I; Rios-Velasco, M A

    2011-01-01

    The real-time holographic gratings recording are studied by the presence of a metallic salt. The experimental process refers to analysis of diffraction efficiency by the influence of humidity in the coating solution on holograms formation in presence of electrical potential. The diffraction efficiency is measured as a function of the exposure energy until reach the saturation. The influence of the hologram parameters to get the diffraction efficiency is studied at room conditions.

  8. US exposure to multiple landscape stressors and climate change

    Becky K. Kerns; John B. Kim; Jeffrey D. Kline; Michelle A. Day

    2016-01-01

    We examined landscape exposure to wildfire potential, insects and disease risk, and urban and exurban development for the conterminous US (CONUS). Our analysis relied on spatial data used by federal agencies to evaluate these stressors nationally. We combined stressor data with a climate change exposure metric to identify when temperature is likely to depart from...

  9. Estimation of optimal hologram recording modes on photothermal materials

    Dzhamankyzov, Nasipbek Kurmanalievich; Ismanov, Yusupzhan Khakimzhanovich; Zhumaliev, Kubanychbek Myrzabekovich; Alymkulov, Samsaly Amanovich

    2018-01-01

    A theoretical analysis of the hologram recording process on photothermal media to estimate the required laser radiation power for the information recording as the function of the spatial frequency and radiation exposure duration is considered. Results of the analysis showed that materials with a low thermal diffusivity are necessary to increase the recording density in these media and the recording should be performed with short pulses to minimize the thermal diffusion length. A solution for the heat conduction equation for photothermal materials heated by an interference laser field was found. The solution obtained allows one to determine the required value of the recording temperature for given spatial frequencies, depending on the thermal physical parameters of the medium and on the power and duration of the heating radiation.

  10. Plasmonic nanoparticle scattering for color holograms.

    Montelongo, Yunuen; Tenorio-Pearl, Jaime Oscar; Williams, Calum; Zhang, Shuang; Milne, William Ireland; Wilkinson, Timothy David

    2014-09-02

    This work presents an original approach to create holograms based on the optical scattering of plasmonic nanoparticles. By analogy to the diffraction produced by the scattering of atoms in X-ray crystallography, we show that plasmonic nanoparticles can produce a wave-front reconstruction when they are sampled on a diffractive plane. By applying this method, all of the scattering characteristics of the nanoparticles are transferred to the reconstructed field. Hence, we demonstrate that a narrow-band reconstruction can be achieved for direct white light illumination on an array of plasmonic nanoparticles. Furthermore, multicolor capabilities are shown with minimal cross-talk by multiplexing different plasmonic nanoparticles at subwavelength distances. The holograms were fabricated from a single subwavelength thin film of silver and demonstrate that the total amount of binary information stored in the plane can exceed the limits of diffraction and that this wavelength modulation can be detected optically in the far field.

  11. Multipoint vibrometry with dynamic and static holograms

    Haist, T.; Lingel, C.; Osten, W. [Institut für Technische Optik, Stuttgart Research Center of Photonic Engineering (SCOPE), University of Stuttgart, D-70569 Stuttgart (Germany); Winter, M.; Giesen, M.; Ritter, F.; Sandfort, K.; Rembe, C. [Polytec GmbH, Polytec-Platz 1-7, D-76337 Waldbronn (Germany); Bendel, K. [Corporate Sector Research and Advanced Engineering, Robert Bosch GmbH, Gerlingen (Germany)

    2013-12-15

    We report on two multipoint vibrometers with user-adjustable position of the measurement spots. Both systems are using holograms for beam deflection. The measurement is based on heterodyne interferometry with a frequency difference of 5 MHz between reference and object beam. One of the systems uses programmable positioning of the spots in the object volume but is limited concerning the light efficiency. The other system is based on static holograms in combination with mechanical adjustment of the measurement spots and does not have such a general efficiency restriction. Design considerations are given and we show measurement results for both systems. In addition, we analyze the sensitivity of the systems which is a major limitation compared to single point scanning systems.

  12. Multipoint vibrometry with dynamic and static holograms.

    Haist, T; Lingel, C; Osten, W; Winter, M; Giesen, M; Ritter, F; Sandfort, K; Rembe, C; Bendel, K

    2013-12-01

    We report on two multipoint vibrometers with user-adjustable position of the measurement spots. Both systems are using holograms for beam deflection. The measurement is based on heterodyne interferometry with a frequency difference of 5 MHz between reference and object beam. One of the systems uses programmable positioning of the spots in the object volume but is limited concerning the light efficiency. The other system is based on static holograms in combination with mechanical adjustment of the measurement spots and does not have such a general efficiency restriction. Design considerations are given and we show measurement results for both systems. In addition, we analyze the sensitivity of the systems which is a major limitation compared to single point scanning systems.

  13. Mode demultiplexer using angularly multiplexed volume holograms.

    Wakayama, Yuta; Okamoto, Atsushi; Kawabata, Kento; Tomita, Akihisa; Sato, Kunihiro

    2013-05-20

    This study proposes a volume holographic demultiplexer (VHDM) for extracting the spatial modes excited in a multimode fiber. A unique feature of the demultiplexer is that it can separate a number of multiplexed modes output from a fiber in different directions by using multi-recorded holograms without beam splitters, which results in a simple configuration as compared with that using phase plates instead of holograms. In this study, an experiment is conducted to demonstrate the basic operations for three LP mode groups to confirm the performance of the proposed VHDM and to estimate the signal-to-crosstalk noise ratio (SNR). As a result, an SNR of greater than 20 dB is obtained.

  14. Toward automated analysis of particle holograms

    Caulfield, H. J.

    1987-01-01

    A preliminary study of approaches for extracting and analyzing data from particle holograms is discussed. It concludes that: (1) for thin spherical particles, out-of-focus methods are optimum; (2) for thin nonspherical particles, out-of-focus methods are useful but must be supplemented by in-focus methods; (3) a complex method of projection and back projection can remove out-of-focus data for deep particles.

  15. Pulsed writing of solid state holograms.

    Gaylord, T. K.; Rabson, T. A.; Tittel, F. K.; Quick, C. R.

    1973-01-01

    The pulsed writing of volume holograms in lithium niobate is reported, both with 200-nsec and 20-nsec duration pulses. This information is of particular interest in high capacity information storage applications since it indicates that writing times at least as short as 20-nsec are readily possible. A series of pulses was used in each case, and the diffraction efficiency was monitored using a He-Ne laser operating at 6328 A and aligned to its corresponding Bragg angle.

  16. Advanced synthetic holograms for security purposes

    Kotačka, Libor; Vízdal, Petr; Behounek, Tomás

    2009-05-01

    Our paper deals with the recent advances in synthetically written optical security devices (DOVIDs) and holograms. The synthesized holographic security elements are recorded with a resolution reaching 500.000 dpi and are specially developed for the "layman-level" security of the most important state valuables and documents, like banknotes and identity cards. We especially pay an attention to such holographic features being impossible to originate through conventional optical holography of matrix based devices.

  17. Fast, large-scale hologram calculation in wavelet domain

    Shimobaba, Tomoyoshi; Matsushima, Kyoji; Takahashi, Takayuki; Nagahama, Yuki; Hasegawa, Satoki; Sano, Marie; Hirayama, Ryuji; Kakue, Takashi; Ito, Tomoyoshi

    2018-04-01

    We propose a large-scale hologram calculation using WAvelet ShrinkAge-Based superpositIon (WASABI), a wavelet transform-based algorithm. An image-type hologram calculated using the WASABI method is printed on a glass substrate with the resolution of 65 , 536 × 65 , 536 pixels and a pixel pitch of 1 μm. The hologram calculation time amounts to approximately 354 s on a commercial CPU, which is approximately 30 times faster than conventional methods.

  18. Optical vortex discrimination with a transmission volume hologram

    Gruneisen, Mark T [Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, NM 87117 (United States); Dymale, Raymond C; Stoltenberg, Kurt E [Boeing Company, PO Box 5670, Albuquerque, NM 87185 (United States); Steinhoff, Nicholas [Optical Sciences Company, 1341 S Sunkist St., Anaheim, CA 92806 (United States)

    2011-08-15

    Transmissive volume holograms are considered as mode-selective optical elements for the de-multiplexing and detecting of optical vortex modes according to the topological charge or mode number. Diffraction of vortex modes by a fundamental mode hologram is modeled using a physical optics model that treats the volume hologram as an angle-dependent transfer function. Diffracted irradiance profiles and diffraction efficiencies are calculated numerically as a function of the incident mode number. The results of the model are compared with experimental results obtained with volume holograms of fundamental and higher-order vortex modes. When considered as a function of detuning between the incident and recorded mode numbers, the measured diffraction efficiencies are found to be invariant with respect to the recorded mode number, provided that the order difference remains unchanged, and in close agreement with the predictions of the model. Measurements are made with a 1.3 mm thick permanent photo-thermo-refractive glass hologram and a 9 mm thick re-writable photorefractive lithium niobate hologram. A liquid-crystal spatial light modulator generates the vortex modes used to record and read the holograms. The results indicate that a simple volume hologram can discriminate between vortex modes; however, adjacent mode discrimination with low crosstalk would require a very thick hologram. Furthermore, broadening of the vortex angular spectrum, due to diffraction at a finite aperture, can adversely affect diffraction efficiencies.

  19. Optical vortex discrimination with a transmission volume hologram

    Gruneisen, Mark T; Dymale, Raymond C; Stoltenberg, Kurt E; Steinhoff, Nicholas

    2011-01-01

    Transmissive volume holograms are considered as mode-selective optical elements for the de-multiplexing and detecting of optical vortex modes according to the topological charge or mode number. Diffraction of vortex modes by a fundamental mode hologram is modeled using a physical optics model that treats the volume hologram as an angle-dependent transfer function. Diffracted irradiance profiles and diffraction efficiencies are calculated numerically as a function of the incident mode number. The results of the model are compared with experimental results obtained with volume holograms of fundamental and higher-order vortex modes. When considered as a function of detuning between the incident and recorded mode numbers, the measured diffraction efficiencies are found to be invariant with respect to the recorded mode number, provided that the order difference remains unchanged, and in close agreement with the predictions of the model. Measurements are made with a 1.3 mm thick permanent photo-thermo-refractive glass hologram and a 9 mm thick re-writable photorefractive lithium niobate hologram. A liquid-crystal spatial light modulator generates the vortex modes used to record and read the holograms. The results indicate that a simple volume hologram can discriminate between vortex modes; however, adjacent mode discrimination with low crosstalk would require a very thick hologram. Furthermore, broadening of the vortex angular spectrum, due to diffraction at a finite aperture, can adversely affect diffraction efficiencies.

  20. Generation of complementary sampled phase-only holograms.

    Tsang, P W M; Chow, Y T; Poon, T-C

    2016-10-03

    If an image is uniformly down-sampled into a sparse form and converted into a hologram, the phase component alone will be adequate to reconstruct the image. However, the appearance of the reconstructed image is degraded with numerous empty holes. In this paper, we present a low complexity and non-iterative solution to this problem. Briefly, two phase-only holograms are generated for an image, each based on a different down-sampling lattice. Subsequently, the holograms are displayed alternately at high frame rate. The reconstructed images of the 2 holograms will appear to be a single, densely sampled image with enhance visual quality.

  1. Development of high-index optical coating for security holograms

    Ahmed, Nadir A. G.

    2000-10-01

    Over the past few years security holograms have grown into a complex business to prevent counterfeiting of security cards, banknotes and the like. Rapid advances in holographic technology have led to a growing requirement for optical materials and coating methods to produce such holograms at reasonable costs. These materials have specific refractive indices and are used to fabricate semi- transparent holograms. The present paper describes a coating process to deposit optical coating on flexible films inside a vacuum web metallizer for the production of high quality semi-transparent holograms.

  2. Chlorpyrifos PBPK/PD model for multiple routes of exposure.

    Poet, Torka S; Timchalk, Charles; Hotchkiss, Jon A; Bartels, Michael J

    2014-10-01

    1. Chlorpyrifos (CPF) is an important pesticide used to control crop insects. Human Exposures to CPF will occur primarily through oral exposure to residues on foods. A physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model has been developed that describes the relationship between oral, dermal and inhalation doses of CPF and key events in the pathway for cholinergic effects. The model was built on a prior oral model that addressed age-related changes in metabolism and physiology. This multi-route model was developed in rats and humans to validate all scenarios in a parallelogram design. 2. Critical biological effects from CPF exposure require metabolic activation to CPF oxon, and small amounts of metabolism in tissues will potentially have a great effect on pharmacokinetics and pharmacodynamic outcomes. Metabolism (bioactivation and detoxification) was therefore added in diaphragm, brain, lung and skin compartments. Pharmacokinetic data are available for controlled human exposures via the oral and dermal routes and from oral and inhalation studies in rats. The validated model was then used to determine relative dermal versus inhalation uptake from human volunteers exposed to CPF in an indoor scenario.

  3. Noise characterization of weighting schemes for combination of multiple exposures

    Kirk, Kristian; Andersen, Hans Jørgen

    2006-01-01

    A method for capturing high intensity dynamic range scenes with a low dynamic range camera consists in taking a series of images with different exposure settings and combining these into a single high dynamic range image. The combined image values are found by weighted averaging of values from...

  4. Relationship between exposure to multiple noise sources and noise annoyance

    Miedema, H.M.E.

    2004-01-01

    Relationships between exposure to noise [metric: day-night level (DNL) or day-evening-night level (DENL)] from a single source (aircraft, road traffic, or railways) and annoyance based on a large international dataset have been published earlier. Also for stationary sources relationships have been

  5. Dual-wavelength phase-shifting digital holography selectively extracting wavelength information from wavelength-multiplexed holograms.

    Tahara, Tatsuki; Mori, Ryota; Kikunaga, Shuhei; Arai, Yasuhiko; Takaki, Yasuhiro

    2015-06-15

    Dual-wavelength phase-shifting digital holography that selectively extracts wavelength information from five wavelength-multiplexed holograms is presented. Specific phase shifts for respective wavelengths are introduced to remove the crosstalk components and extract only the object wave at the desired wavelength from the holograms. Object waves in multiple wavelengths are selectively extracted by utilizing 2π ambiguity and the subtraction procedures based on phase-shifting interferometry. Numerical results show the validity of the proposed technique. The proposed technique is also experimentally demonstrated.

  6. [Multiple mere exposure effect: category evaluation measured in the Go/No-go association task (GNAT)].

    Kawakami, Naoaki; Yoshida, Fujio

    2011-12-01

    The effect on likability of multiple subliminal exposures to the same person was investigated. Past studies on the mere exposure effect indicated a correlation between the frequency of repeated exposure to the same stimulus and likability. We proposed that exposure to various stimuli of the same person would have a stronger effect on likability. Participants were subliminally exposed to photographs of a person's face taken from seven angles (multi-angle-exposure) three times each (Experiment 1), or photographs of a person with seven facial expressions (multi-expression-exposure) three times each (Experiment 2). Then, the likability toward the exposed person was measured using the Go/No-go Association Task. The results indicated that the effect of the multiple exposures from various angles was equivalent to exposure to only one full-face photograph shown 21 times (Experiment 1). Moreover, likability was significantly higher in the case of exposure to various facial expressions than for exposure to only a single facial expression (Experiment 2). The results suggest that exposure to various stimuli in a category is more effective than repeated exposure to a single stimulus for increasing likability.

  7. PUBLIC EXPOSURE TO MULTIPLE RF SOURCES IN GHANA.

    Deatanyah, P; Abavare, E K K; Menyeh, A; Amoako, J K

    2018-03-16

    This paper describes an effort to respond to the suggestion in World Health Organization (WHO) research agenda to better quantify potential exposure levels from a range of radiofrequency (RF) sources at 200 public access locations in Ghana. Wide-band measurements were performed-with a spectrum analyser and a log-periodic antenna using three-point spatial averaging method. The overall results represented a maximum of 0.19% of the ICNIRP reference levels for public exposure. These results were generally lower than found in some previous but were 58% (2.0 dB) greater, than found in similar work conducted in the USA. Major contributing sources of RF fields were identified to be FM broadcast and mobile base station sites. Three locations with the greatest measured RF fields could represent potential areas for epidemiological studies.

  8. Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

    Freiesleben, Trine; Sohbati, Reza; Murray, Andrew; Jain, Mayank; Al Khasawneh, Sahar; Hvidt, Søren; Jakobsen, Bo

    2015-01-01

    Interest in the optically stimulated luminescence (OSL) dating of rock surfaces has increased significantly over the last few years, as the potential of the method has been explored. It has been realized that luminescence-depth profiles show qualitative evidence for multiple daylight exposure and burial events. To quantify both burial and exposure events a new mathematical model is developed by expanding the existing models of evolution of luminescence–depth profiles, to include repeated sequential events of burial and exposure to daylight. This new model is applied to an infrared stimulated luminescence-depth profile from a feldspar-rich granite cobble from an archaeological site near Aarhus, Denmark. This profile shows qualitative evidence for multiple daylight exposure and burial events; these are quantified using the model developed here. By determining the burial ages from the surface layer of the cobble and by fitting the new model to the luminescence profile, it is concluded that the cobble was well bleached before burial. This indicates that the OSL burial age is likely to be reliable. In addition, a recent known exposure event provides an approximate calibration for older daylight exposure events. This study confirms the suggestion that rock surfaces contain a record of exposure and burial history, and that these events can be quantified. The burial age of rock surfaces can thus be dated with confidence, based on a knowledge of their pre-burial light exposure; it may also be possible to determine the length of a fossil exposure, using a known natural light exposure as calibration. - Highlights: • Evidence for multiple exposure and burial events in the history of a single cobble. • OSL rock surface dating model improved to include multiple burial/exposure cycles. • Application of the new model quantifies burial and exposure events.

  9. Activated crystals of fluorite type as photochromic mediums for recording of volumetric holograms

    Arkhangel'skaya, V.A.; Ashcheulov, Yu.V.; Perfilov, V.N.; Rejterov, V.M.; Sukhanov, V.I.; Feofilov, P.P.

    1975-01-01

    The paper is a study of the mechanism of photochromism and of the photochromic and holographic properties of fluorides of alkaline earth metals with one and two rare-earth activators. It is shown that the angular selectivity of ''thick'' (d approximately 2-5 mm) crystals is 2-3 angular minutes and that the optimum energy exposures, corresponding to the maximum diffraction efficiency values, are 0.1-1.0 J/cm 2 for singly-activated crystals and 1.0-10 J/cm 2 for crystals with two activators. The diffraction efficiencies of holograms of both types of crystals is in the range of approximately 0.1-0.2%. The experimental data are compared with calculations made for photochromic crystals with pigmentation centres. It is suggested that the materials studied can serve as a basis for measuring volumetric holograms. (author)

  10. GPC-enhanced read-out of holograms

    Villangca, Mark Jayson; Bañas, Andrew Rafael; Palima, Darwin

    2015-01-01

    -holograms are encoded to create reconfigurable spot arrays and arbitrary extended patterns. For a given laser power, our experimental results show a significant intensity gain in the resulting diffraction patterns when we illuminate the holograms with a GPC-shaped beam as compared to the more common practice of hard...

  11. The Creation and Varied Applications of Educational Holograms.

    Layng, Jacqueline M.

    The potential of holograms has been left virtually untapped in the field of education. A hologram can be described as a three-dimensional photographic record of the interference pattern of two superimposed beams of coherent light. Holography requires: (1) high-resolution film; (2) a laser, often a red-beamed helium neon laser; (3) optical…

  12. Optimizing the efficiency of femtosecond-laser-written holograms

    Wædegaard, Kristian Juncher; Hansen, Henrik Dueholm; Balling, Peter

    2013-01-01

    Computer-generated binary holograms are written on a polished copper surface using single 800-nm, 120-fs pulses from a 1-kHz-repetition-rate laser system. The hologram efficiency (i.e. the power in the holographic reconstructed image relative to the incoming laser power) is investigated...

  13. Tilt-effect of holograms and images displayed on a spatial light modulator.

    Harm, Walter; Roider, Clemens; Bernet, Stefan; Ritsch-Marte, Monika

    2015-11-16

    We show that a liquid crystal spatial light modulator (LCOS-SLM) can be used to display amplitude images, or phase holograms, which change in a pre-determined way when the display is tilted, i.e. observed under different angles. This is similar to the tilt-effect (also called "latent image effect") known from various security elements ("kinegrams") on credit cards or bank notes. The effect is achieved without any specialized optical components, simply by using the large phase shifting capability of a "thick" SLM, which extends over several multiples of 2π, in combination with the angular dependence of the phase shift. For hologram projection one can use the fact that the phase of a monochromatic wave is only defined modulo 2π. Thus one can design a phase pattern extending over several multiples of 2π, which transforms at different readout angles into different 2π-wrapped phase structures, due to the angular dependence of the modulo 2π operation. These different beams then project different holograms at the respective readout angles. In amplitude modulation mode (with inserted polarizer) the intensity of each SLM pixel oscillates over several periods when tuning its control voltage. Since the oscillation period depends on the readout angle, it is possible to find a certain control voltage which produces two (or more) selectable gray levels at a corresponding number of pre-determined readout angles. This is done with all SLM pixels individually, thus constructing different images for the selected angles. We experimentally demonstrate the reconstruction of multiple (Fourier- and Fresnel-) holograms, and of different amplitude images, by readout of static diffractive patterns in a variable angular range between 0° and 60°.

  14. Orthodontic exposure of multiple lmpactions: a case report.

    Munda-Lacson, Maridin C; Venugopal, Adith

    2014-01-01

    There are rare cases of impacted permanent central incisors with dilacerations, a dental deformity characterized by pronounced angulations of the longitudinal tooth axis. Impaction of maxillary canines is an orthodontic anomaly that causes facial and dentoalveolar system problems, both functional and esthetic. A combination of surgery and orthodontics is important in bringing impacted teeth to their ideal position in the dental arch. This is a case report of a 10-year-old patient with impacted and dilacerated right central incisor and impacted left maxillary canine, following surgical exposure and appropriate orthodontic traction, the impacted teeth were surgically exposed and aligned into the dental arch.

  15. Understanding the Impact of Exposure Patterns on Risks from Combined Exposures to Multiple Chemicals

    The talk was invited so there is no formal abstract. However, the focus of the talk is on the use of exposure information in the evaluation of risks from combined exposures to chemicals. The talk presents a bit of history and several case studies. All empirical data presented hav...

  16. E-Beam Written Computer Generated Holograms.

    1983-08-01

    the V2 parabola is tested without aid of the computer generated hologram, and the interferogram of Figure 3-5a results. It shows about 40 waves of...bymricl crain Atso, whee PCGH ae • " in ihe lowret Thae vroush considerations wih respect t he degnos Thi mCHaeanis. cussed in the folowing siectionsuo.e...spacing of 0.5 has proven to be a greater challenge than achieving the correct milling depth, particularly for higher spatial frequency pat- terns

  17. Sugar holograms with erioglaucine and tartrazine

    Mejias-Brizuela, N. Y.; Olivares-Pérez, A.; Páez-Trujillo, G.; Fuentes-Tapia, I.

    2007-09-01

    An artificial green colorant, composed by erioglaucine (Blue 1) and tartrazine (Yellow 5), was employed in a sugar matrix to improve the material sensibility and to make a comparative analysis of the diffraction efficiency parameter, for holograms replications, the holographic pattern was obtained by a computer and recorded in sugar films and in modified sugar (sugar-colorant). Conventional lithography and UV radiation were used. The results show that the behavior diffraction efficiency of the sugar-colorant films is slightly larger than in the sugar matrix under the same recording conditions.

  18. High speed phase retrieval of in-line holograms by the assistance of corresponding off-axis holograms.

    Orzó, László

    2015-06-29

    Retrieving correct phase information from an in-line hologram is difficult as the object wave field and the diffractions of the zero order and the conjugate object term overlap. The existing iterative numerical phase retrieval methods are slow, especially in the case of high Fresnel number systems. Conversely, the reconstruction of the object wave field from an off-axis hologram is simple, but due to the applied spatial frequency filtering the achievable resolution is confined. Here, a new, high-speed algorithm is introduced that efficiently incorporates the data of an auxiliary off-axis hologram in the phase retrieval of the corresponding in-line hologram. The efficiency of the introduced combined phase retrieval method is demonstrated by simulated and measured holograms.

  19. Simple method of modelling of digital holograms registering and their optical reconstruction

    Evtikhiev, N N; Cheremkhin, P A; Krasnov, V V; Kurbatova, E A; Molodtsov, D Yu; Porshneva, L A; Rodin, V G

    2016-01-01

    The technique of modeling of digital hologram recording and image optical reconstruction from these holograms is described. The method takes into account characteristics of the object, digital camera's photosensor and spatial light modulator used for digital holograms displaying. Using the technique, equipment can be chosen for experiments for obtaining good reconstruction quality and/or holograms diffraction efficiency. Numerical experiments were conducted. (paper)

  20. Glyphosate accumulation, translocation, and biological effects in Coffea arabica after single and multiple exposures

    Schrübbers, Lars Christoph; Valverde, Bernal E.; Strobel, Bjarne W.

    2016-01-01

    In perennial crops like coffee, glyphosate drift exposure can occur multiple times during its commercial life span. Due to limited glyphosate degradation in higher plants, a potential accumulation of glyphosate could lead to increased biological effects with increased exposure frequency....... In this study, we investigated glyphosate translocation over time, and its concentration and biological effects after single and multiple simulated spray-drift exposures. Additionally, shikimic acid/glyphosate ratios were used as biomarkers for glyphosate binding to its target enzyme.Four weeks after...... the exposure, glyphosate was continuously translocated. Shikimic acid levels were lin-ear correlated with glyphosate levels. After two months, however, glyphosate appeared to have reduced activity. In the greenhouse, multiple applications resulted in higher internal glyphosate concentrations.The time...

  1. Wavefront reconstruction using computer-generated holograms

    Schulze, Christian; Flamm, Daniel; Schmidt, Oliver A.; Duparré, Michael

    2012-02-01

    We propose a new method to determine the wavefront of a laser beam, based on modal decomposition using computer-generated holograms (CGHs). Thereby the beam under test illuminates the CGH with a specific, inscribed transmission function that enables the measurement of modal amplitudes and phases by evaluating the first diffraction order of the hologram. Since we use an angular multiplexing technique, our method is innately capable of real-time measurements of amplitude and phase, yielding the complete information about the optical field. A measurement of the Stokes parameters, respectively of the polarization state, provides the possibility to calculate the Poynting vector. Two wavefront reconstruction possibilities are outlined: reconstruction from the phase for scalar beams and reconstruction from the Poynting vector for inhomogeneously polarized beams. To quantify single aberrations, the reconstructed wavefront is decomposed into Zernike polynomials. Our technique is applied to beams emerging from different kinds of multimode optical fibers, such as step-index, photonic crystal and multicore fibers, whereas in this work results are exemplarily shown for a step-index fiber and compared to a Shack-Hartmann measurement that serves as a reference.

  2. Improvement of viewing-zone angle and image quality of digital holograms

    Nomura, Takanori, E-mail: nom@sys.wakayama-u.ac.j [Faculty of Systems Enigneering, Wakayama Univesity, 930 Sakaedani, Wakayama, 640-8510 (Japan)

    2010-02-01

    The method to improve of a viewing-zone angle and an image quality of a digital hologram is presented. A number of digital holograms of a central object are recorded from the position on the circumference. The holograms are used for a hologram synthesis to improve the image quality from whole viewing-zone angle. The synthesis is achieved by a correlation between a hologram and numerically propagated holograms. The large-sized synthesized digital hologram has a wide viewing-zone angle and less speckles. Some experimental results are shown to confirm the proposed method.

  3. Phase holograms in PMMA with proximity effect correction

    Maker, Paul D.; Muller, R. E.

    1993-01-01

    Complex computer generated phase holograms (CGPH's) have been fabricated in PMMA by partial e-beam exposure and subsequent partial development. The CGPH was encoded as a sequence of phase delay pixels and written by the JEOL JBX-5D2 E-beam lithography system, a different dose being assigned to each value of phase delay. Following carefully controlled partial development, the pattern appeared rendered in relief in the PMMA, which then acts as the phase-delay medium. The exposure dose was in the range 20-200 micro-C/sq cm, and very aggressive development in pure acetone led to low contrast. This enabled etch depth control to better than plus or minus lambda(sub vis)/60. That result was obtained by exposing isolated 50 micron square patches and measuring resist removal over the central area where the proximity effect dose was uniform and related only to the local exposure. For complex CGPH's with pixel size of the order of the e-beam proximity effect radius, the patterns must be corrected for the extra exposure caused by electrons scattered back up out of the substrate. This has been accomplished by deconvolving the two-dimensional dose deposition function with the desired dose pattern. The deposition function, which plays much the same role as an instrument response function, was carefully measured under the exact conditions used to expose the samples. The devices fabricated were designed with 16 equal phase steps per retardation cycle, were up to 1 cm square, and consisted of up to 100 million 0.3-2.0 micron square pixels. Data files were up to 500 MB long and exposure times ranged to tens of hours. A Fresnel phase lens was fabricated that had diffraction limited optical performance with better than 85 percent efficiency.

  4. Multiple exposure routes of a pesticide exacerbate effects on a grazing mayfly.

    Pristed, Mathias Joachim Skov; Bundschuh, Mirco; Rasmussen, Jes Jessen

    2016-09-01

    Hydrophobic pesticides such as pyrethroid insecticides tend to occur in their soluble form mainly as transient pulses in streams. In addition, they are regularly detected in significant quantities adsorbed to stream sediments and other organic in-stream structures. Consequently, stream biota is likely subjected to pesticide exposure via multiple routes. In this study we aimed at investigating the influence of exposure routes for the pyrethroid insecticide lambda-cyhalothrin on the grazing mayfly Heptagenia sulphurea. Therefore, H. sulphurea was exposed to lambda-cyhalothrin via single- (water or biofilm) or biphasic exposure (water and biofilm) at environmentally realistic concentrations (0, 0.1, 1μgL(-1)) and exposure duration (2h) in a full factorial design (n=5). Mortality, moulting frequency, and biofilm accrual (proxy for feeding rate) were recorded subsequent to a 7 d post exposure period. Mortality significantly increased and moulting frequency significantly decreased with increasing concentrations of lambda-cyhalothrin in the water phase whereas exposure via biofilm prompted no significant effects on these endpoints (α=0.05). Effect predictions systematically underestimated and overestimated effects for mortality and moulting frequency, respectively. Similarly, mayfly feeding rate was significantly reduced by water phase exposure whereas pre-exposed biofilm did not significantly affect this variable. However, we found a significant but non-systematic interaction between water phase and biofilm exposure on mayfly feeding rate. Our results show that exposure to the same pesticide via multiple exposure routes may increase the magnitude of effects beyond the level predicted from single phase exposures which has clear implications for the aquatic risk assessment of hydrophobic pesticides. However, our results additionally reveal that interactions between pesticide exposure routes may vary between selected dependent variables. We emphasize that unravelling the

  5. Properties Of Reflection Holograms Recorded In Polaroid's DMP-128 Photopolymer

    Ingwall, R. T.; Troll, M.; Vetterling, W. T.

    1987-06-01

    Optical and microstructural properties of reflection holograms recorded in DMP-128 are reported. The optical properties are determined from transmission spectra of the holograms by ignoring the relatively small effects of light scattering and absorption. Microstructure is revealed by light and electron microscopic examination of hologram sections prepared either by diamond grit abrasion or by freeze fracture. Fringe planes are clearly seen with both sectioning procedures. The spacing between adjacent planes is strongly affected by processing conditions. Standard processing produces reflection holograms with fringe plane spacing that decreases continuously from the film:substrate interface to the film:air interface. These holograms have wide spectral bandwidths (100-200nm) and irregular band shapes. Narrow bandwidth holograms are produced from slightly more complicated processing steps. The optical properties of both types of holograms are compared to a theoretical model developed to account for nonuniform fringe plane spacing. Important experimental features such as spectral bandwidth and diffraction efficiency are readily explained by the theory and the observed microstructure.

  6. Methods of compression of digital holograms, based on 1-level wavelet transform

    Kurbatova, E A; Cheremkhin, P A; Evtikhiev, N N

    2016-01-01

    To reduce the size of memory required for storing information about 3D-scenes and to decrease the rate of hologram transmission, digital hologram compression can be used. Compression of digital holograms by wavelet transforms is among most powerful methods. In the paper the most popular wavelet transforms are considered and applied to the digital hologram compression. Obtained values of reconstruction quality and hologram's diffraction efficiencies are compared. (paper)

  7. Exposure estimates based on broadband elf magnetic field measurements versus the ICNIRP multiple frequency rule

    Paniagua, Jesus M.; Rufo, Montana; Jimenez, Antonio; Pachon, Fernando T.; Carrero, Julian

    2015-01-01

    The evaluation of exposure to extremely low-frequency (ELF) magnetic fields using broadband measurement techniques gives satisfactory results when the field has essentially a single frequency. Nevertheless, magnetic fields are in most cases distorted by harmonic components. This work analyses the harmonic components of the ELF magnetic field in an outdoor urban context and compares the evaluation of the exposure based on broadband measurements with that based on spectral analysis. The multiple frequency rule of the International Commission on Non-ionizing Radiation Protection (ICNIRP) regulatory guidelines was applied. With the 1998 ICNIRP guideline, harmonics dominated the exposure with a 55 % contribution. With the 2010 ICNIRP guideline, however, the primary frequency dominated the exposure with a 78 % contribution. Values of the exposure based on spectral analysis were significantly higher than those based on broadband measurements. Hence, it is clearly necessary to determine the harmonic components of the ELF magnetic field to assess exposure in urban contexts. (authors)

  8. Application of Mathematical Symmetrical Group Theory in the Creation Process of Digital Holograms

    Agustín Pérez-Ramírez

    2017-01-01

    Full Text Available This work presents an algorithm to reduce the multiplicative computational complexity in the creation of digital holograms, where an object is considered as a set of point sources using mathematical symmetry properties of both the core in the Fresnel integral and the image. The image is modeled using group theory. This algorithm has multiplicative complexity equal to zero and an additive complexity (k-1N2 for the case of sparse matrices or binary images, where k is the number of pixels other than zero and N2 is the total of points in the image.

  9. Environmental conditions influence for real-time hologram formation on dichromated polyvinyl alcohol NiCl{sub 2}{center_dot}6H{sub 2}O doped films

    Fontanilla-Urdaneta, R C; Olivares-Perez, A; Fuentes-Tapia, I; Rios-Velasco, M A, E-mail: rfontanilla@inaoep.mx, E-mail: olivares@inaoep.mx, E-mail: ifuentes@inaoep.mx, E-mail: moni_arv@hotmail.com [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Luis Enrique Erro No. 1 Tonantzintla, Puebla (Mexico)

    2011-01-01

    The real-time holographic gratings recording are studied by the presence of a metallic salt. The experimental process refers to analysis of diffraction efficiency by the influence of humidity in the coating solution on holograms formation in presence of electrical potential. The diffraction efficiency is measured as a function of the exposure energy until reach the saturation. The influence of the hologram parameters to get the diffraction efficiency is studied at room conditions.

  10. Reconstruction of Double-Exposed Terahertz Hologram of Non-isolated Object

    Hu, Jiaqi; Li, Qi; Chen, Guanghao

    2016-04-01

    When the non-isolated imaging objects are complex or critical imaging precision is required, single-exposure digital hologram technique may be insufficient. So in this paper, double-exposure method is adopted in 2.52-THz inline digital holography simulations and experiments. Experimental results indicate that, compared with the results reconstructed by single-exposure amplitude-constrained phase retrieval algorithm (S-APRA), double-exposure phase-constrained phase retrieval algorithm (D-PPRA) increases the contrast of the reconstruction image by 0.146 and double-exposure amplitude-constrained phase retrieval algorithm (D-APRA) increases the contrast by 0.225. In addition, when applied to non-isolated object reconstruction, phase retrieval algorithms with only amplitude constraint on the object plane work better than those with both amplitude and phase constraints.

  11. Holograms for power-efficient excitation of optical surface waves

    Ignatov, Anton I.; Merzlikin, Alexander M.

    2018-02-01

    A method for effective excitation of optical surface waves based on holography principles has been proposed. For a particular example of excitation of a plasmonic wave in a dielectric layer on metal the efficiency of proposed volume holograms in the dielectric layer has been analyzed in comparison with optimized periodic gratings in the dielectric layer. Conditions when the holograms are considerably more efficient than the gratings have been found out. In addition, holograms recorded in two iterations have been proposed and studied. Such holograms are substantially more efficient than the optimized periodic gratings for all incidence angles of an exciting Gaussian beam. The proposed method is universal: it can be extended for efficient excitation of different types of optical surface waves and optical waveguide modes.

  12. Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

    Freiesleben, Trine Holm; Sohbati, Reza; Murray, Andrew

    2015-01-01

    Interest in the optically stimulated luminescence (OSL) dating of rock surfaces has increased significantly over the last few years, as the potential of the method has been explored. It has been realized that luminescence-depth profiles show qualitative evidence for multiple daylight exposure...... and burial events. To quantify both burial and exposure events a new mathematical model is developed by expanding the existing models of evolution of luminescenceedepth profiles, to include repeated sequential events of burial and exposure to daylight. This new model is applied to an infrared stimulated...... events. This study confirms the suggestion that rock surfaces contain a record of exposure and burial history, and that these events can be quantified. The burial age of rock surfaces can thus be dated with confidence, based on a knowledge of their pre-burial light exposure; it may also be possible...

  13. Chemosensory perception, symptoms and autonomic responses during chemical exposure in multiple chemical sensitivity

    Andersson, Linus; Claeson, Anna Sara; Dantoft, Thomas Meinertz

    2016-01-01

    Purpose: Multiple chemical sensitivity (MCS) is a prevalent medically unexplained symptom characterized by symptom reactions to everyday chemical exposure below hygienic thresholds. The aim of this study was to investigate the expressions of hyper-reactivity in MCS during whole-body exposure to low...... concentrations of the odorant n-butanol. Methods: We exposed 18 participants with MCS and 18 non-ill controls to a low concentration of the odorant n-butanol using an exposure chamber. The first 10 min constituted blank exposure, after which the n-butanol concentration increased and reached a plateau at 11.5 mg....../m3. Results: MCS participants, compared with controls, reported greater perceived odor intensities, more unpleasantness to the exposure and increasing symptoms over time. MCS participants also expressed higher pulse rate and lower pulse rate variability than controls did. No group differences were...

  14. A multiple objective test assembly approach for exposure control problems in Computerized Adaptive Testing

    Theo J.H.M. Eggen

    2010-01-01

    Full Text Available Overexposure and underexposure of items in the bank are serious problems in operational computerized adaptive testing (CAT systems. These exposure problems might result in item compromise, or point at a waste of investments. The exposure control problem can be viewed as a test assembly problem with multiple objectives. Information in the test has to be maximized, item compromise has to be minimized, and pool usage has to be optimized. In this paper, a multiple objectives method is developed to deal with both types of exposure problems. In this method, exposure control parameters based on observed exposure rates are implemented as weights for the information in the item selection procedure. The method does not need time consuming simulation studies, and it can be implemented conditional on ability level. The method is compared with Sympson Hetter method for exposure control, with the Progressive method and with alphastratified testing. The results show that the method is successful in dealing with both kinds of exposure problems.

  15. Information properties of a hologram of mutually conjugate waves

    Rubanov, A.S.; Serebryakova, L.M.

    1995-01-01

    A theoretical study of information properties of a correlation response to a fragment of an image of a thin referenceless hologram of mutually conjugate waves that is recorded with a phase-conjugating (PC) mirror is reported. It is shown that this hologram reconstructs a full image in reflected light and can be used as an associative storage device and as a selective PC mirror. 7 refs., 1 fig

  16. Singular-value demodulation of phase-shifted holograms.

    Lopes, Fernando; Atlan, Michael

    2015-06-01

    We report on phase-shifted holographic interferogram demodulation by singular-value decomposition. Numerical processing of optically acquired interferograms over several modulation periods was performed in two steps: (1) rendering of off-axis complex-valued holograms by Fresnel transformation of the interferograms; and (2) eigenvalue spectrum assessment of the lag-covariance matrix of hologram pixels. Experimental results in low-light recording conditions were compared with demodulation by Fourier analysis, in the presence of random phase drifts.

  17. Real-time colour hologram generation based on ray-sampling plane with multi-GPU acceleration.

    Sato, Hirochika; Kakue, Takashi; Ichihashi, Yasuyuki; Endo, Yutaka; Wakunami, Koki; Oi, Ryutaro; Yamamoto, Kenji; Nakayama, Hirotaka; Shimobaba, Tomoyoshi; Ito, Tomoyoshi

    2018-01-24

    Although electro-holography can reconstruct three-dimensional (3D) motion pictures, its computational cost is too heavy to allow for real-time reconstruction of 3D motion pictures. This study explores accelerating colour hologram generation using light-ray information on a ray-sampling (RS) plane with a graphics processing unit (GPU) to realise a real-time holographic display system. We refer to an image corresponding to light-ray information as an RS image. Colour holograms were generated from three RS images with resolutions of 2,048 × 2,048; 3,072 × 3,072 and 4,096 × 4,096 pixels. The computational results indicate that the generation of the colour holograms using multiple GPUs (NVIDIA Geforce GTX 1080) was approximately 300-500 times faster than those generated using a central processing unit. In addition, the results demonstrate that 3D motion pictures were successfully reconstructed from RS images of 3,072 × 3,072 pixels at approximately 15 frames per second using an electro-holographic reconstruction system in which colour holograms were generated from RS images in real time.

  18. Sunlight exposure and sun sensitivity associated with disability progression in multiple sclerosis

    D'hooghe, M. B.; Haentjens, P.; Nagels, G.; Garmyn, M.; De Keyser, J.

    Background: Sunlight and vitamin D have been inversely associated with the risk of multiple sclerosis (MS). Objective: We investigated sunlight exposure and sun sensitivity in relation to disability progression in MS. Methods: We conducted a survey among persons with MS, registered by the Flemish MS

  19. Mapping the future: U.S. exposure to multiple landscape stressors

    Marie Oliver; Becky Kerns; John Kim; Jeff. Kline

    2017-01-01

    Landscape exposure to multiple stressors can pose risks to human health, biodiversity, and ecosystem services. Attempts to study, control, or mitigate these stressors can strain public and private budgets. An interdisciplinary team of Pacific Northwest Research Station and Oregon State University scientists created maps of the conterminous United States that indicate...

  20. Alpha-risk: a European project on the quantification of risks associated with multiple radiation exposures

    Laurier, D.; Monchaux, G.; Tirmarche, M.; Darby, S.; Cardis, E.; Binks, K.; Hofmann, W.; Muirhead, C.

    2006-01-01

    The Alpha-Risk research project is being conducted within the Sixth European Framework Programme (EC-FP6, 2005 -2008). It aims to improve the quantification of risks associated with multiple exposures, taking into account the contribution of different radionuclides and external exposure using specific organ dose calculations. The Alpha-Risk Consortium involves 18 partners from 9 countries, and is coordinated by the IRSN. Its composition allows a multidisciplinary collaboration between researchers in epidemiology, dosimetry, statistics, modelling and risk assessment. Alpha-Risk brings together major epidemiological studies in Europe, which are able to evaluate long-term health effects of internal exposure from radionuclides. It includes large size cohort and case-control studies, with accurate registration of individual annual exposures: uranium miner studies, studies on lung cancer and indoor radon exposure, and studies of lung cancer and leukaemia among nuclear workers exposed to transuranic nuclides (mainly uranium and plutonium), for whom organ doses will be reconstructed individually. The contribution of experts in dosimetry will allow the calculation of organ doses in presence of multiple exposures (radon decay products, uranium dust and external gamma exposure). Expression of the risk per unit organ dose will make it possible to compare results with those from other populations exposed to external radiation. The multidisciplinary approach of Alpha-Risk promotes the development of coherent and improved methodological approaches regarding risk modelling. A specific work - package is dedicated to the integration of results and their use for risk assessment, especially for radon. Alpha-Risk will contribute to a better understanding of long-term health risks following chronic low doses from internal exposures. The project also has the great potential to help resolve major public health concerns about the effects of low and/or protracted exposures, especially

  1. Intrathecal Pump Exposure to Electromagnetic Interference: A Report of Device Interrogation following Multiple ECT Sessions.

    Bicket, Mark C; Hanna, George M

    2016-02-01

    Intrathecal drug delivery systems represent an increasingly common treatment modality for patients with a variety of conditions, including chronic pain and spasticity. Pumps rely on electronic programming to properly control and administer highly concentrated medications. Electromagnetic interference (EMI) is a known exposure that may cause a potential patient safety issue stemming from direct patient injury, pump damage, or changes to pump operation or flow rate. The objective of our case report was to describe an approach to evaluating a patient with a pump prior to and following exposure to EMI from electroconvulsive therapy (ECT), as well as to document findings from device interrogations associated with this event. Case report. Academic university-based pain management center. We present the case of a patient with an intrathecal pump who underwent multiple exposures to EMI in the form of 42 ECT sessions. Interrogation of the intrathecal drug delivery system revealed no safety issues following ECT sessions. At no time were error messages, unintentional changes in event logs, unintentional changes in pump settings, or evidence of pump stall or over-infusion noted. Communication with multiple entities (patient, family, consulting physicians, and device manufacturer) and maintaining vigilance through device interrogation both before and after EMI exposure are appropriate safeguards to mitigate the risk and detect potential adverse events of EMI with intrathecal drug delivery systems. Given the infrequent reports of device exposure to ECT, best practices may be derived from experience with EMI exposure from magnetic resonance imaging (MRI). Although routine EMI exposure to intrathecal drug delivery systems should be avoided, we describe one patient with repeated exposure to ECT without apparent complication.

  2. Correction of over and under exposure images using multiple lighting system

    Im, Jonghoon; Fujii, Hiromitsu; Yamashita, Atsushi; Asama, Hajime

    2015-01-01

    When images are acquired in bright condition, it can cause a loss of highlight details (over exposure) in bright area and a loss of shadow details (under exposure) in dark area. Over and under exposure causes a big problem when people investigate dangerous place like Fukushima nuclear power plant through the camera attached remote control robot. In this paper, we propose a method to correct the over and under exposure image to solve the problem. The image processing consists of four steps. Firstly, multiple images are acquired by alternately turning on and off each illumination which set in different positions. Then the image obtained first is defined as input image 1, the image obtained second is defined as input image 2 and the image obtained N-th is defined as input image N. Secondly, luminance of the images is corrected. Thirdly, over and under exposure regions in the image are extracted from the input image 1. Finally, the over and under exposure regions in the input image 1 are compensated by other images. The results show that the over and under exposure regions in the input image are recovered by our proposed method. (author)

  3. Prevalence and predictors of exposure to multiple metals in preschool children from Montevideo, Uruguay

    Kordas, Katarzyna; Queirolo, Elena I.; Ettinger, Adrienne S.; Wright, Robert O.; Stoltzfus, Rebecca J.

    2010-01-01

    The extent of children's exposure to multiple toxic metals is not well described in many developing countries. We examined metal exposures in young children (6-37 months) from Montevideo, Uruguay and their mothers (15-47 years) participating in a community-based study. Hair samples collected from 180 children and their mothers were analyzed for: lead (Pb), cadmium (Cd), manganese (Mn), and arsenic (As) concentration using inductively coupled plasma-mass spectrometry (ICP-MS). Median metal levels (μg/g) were: Pb 13.69, Mn 1.45, Cd 0.17, and As 0.09 for children and Pb 4.27, Mn 1.42, Cd 0.08, and As 0.02 for mothers. Of the child and maternal samples, 1.7% and 2.9% were below the limit of detection (LOD) for Cd, and 21.3% and 38.5% were below the LOD for As, respectively. Correlations between maternal and child levels ranged 0.38-0.55 (p < 0.01). Maternal hair metal levels were the strongest predictors of metal concentrations in children's hair. Girls had significantly lower As levels than boys (p < 0.01) but did not differ on other metals. In addition, in bivariate logistic regressions predicting the likelihood that the child would be exposed to multiple metals, hemoglobin < 10.5 g/dL (OR = 2.12, p < 0.05), blood lead (OR = 1.17, p < 0.01), and the mother being exposed to two or more metals (OR = 3.34, p < 0.01) were identified as significant predictors of increased likelihood of multiple metal exposure. Older child age (OR = 0.96, p < 0.05), higher maternal education (OR = 0.35, p < 0.01), and higher number of household possessions (OR = 0.83, p < 0.01) were significantly associated with decreased likelihood of multiple metal exposure. Preschool children in Uruguay are exposed to multiple metals at levels that in other studies have been associated with cognitive and behavioral deficits. Sources of exposure, as well as cognitive and behavioral consequences of multiple metal exposure, should be investigated in this population.

  4. Prevalence and predictors of exposure to multiple metals in preschool children from Montevideo, Uruguay

    Kordas, Katarzyna, E-mail: Kxk48@psu.edu [Department of Nutritional Sciences, Pennsylvania State University, 110 Chandlee Laboratory, University Park, PA 16802 (United States); Queirolo, Elena I. [Center for Research, Catholic University of Uruguay, Montevideo (Uruguay); Clinic for Environmental Contaminants, Pereira Rossell Hospital, Montevideo (Uruguay); Ettinger, Adrienne S.; Wright, Robert O. [Department of Environmental Health, Harvard School of Public Health, Boston, MA (United States); Stoltzfus, Rebecca J. [Division of Nutritional Sciences, Cornell University, Ithaca, NY (United States)

    2010-09-15

    The extent of children's exposure to multiple toxic metals is not well described in many developing countries. We examined metal exposures in young children (6-37 months) from Montevideo, Uruguay and their mothers (15-47 years) participating in a community-based study. Hair samples collected from 180 children and their mothers were analyzed for: lead (Pb), cadmium (Cd), manganese (Mn), and arsenic (As) concentration using inductively coupled plasma-mass spectrometry (ICP-MS). Median metal levels ({mu}g/g) were: Pb 13.69, Mn 1.45, Cd 0.17, and As 0.09 for children and Pb 4.27, Mn 1.42, Cd 0.08, and As 0.02 for mothers. Of the child and maternal samples, 1.7% and 2.9% were below the limit of detection (LOD) for Cd, and 21.3% and 38.5% were below the LOD for As, respectively. Correlations between maternal and child levels ranged 0.38-0.55 (p < 0.01). Maternal hair metal levels were the strongest predictors of metal concentrations in children's hair. Girls had significantly lower As levels than boys (p < 0.01) but did not differ on other metals. In addition, in bivariate logistic regressions predicting the likelihood that the child would be exposed to multiple metals, hemoglobin < 10.5 g/dL (OR = 2.12, p < 0.05), blood lead (OR = 1.17, p < 0.01), and the mother being exposed to two or more metals (OR = 3.34, p < 0.01) were identified as significant predictors of increased likelihood of multiple metal exposure. Older child age (OR = 0.96, p < 0.05), higher maternal education (OR = 0.35, p < 0.01), and higher number of household possessions (OR = 0.83, p < 0.01) were significantly associated with decreased likelihood of multiple metal exposure. Preschool children in Uruguay are exposed to multiple metals at levels that in other studies have been associated with cognitive and behavioral deficits. Sources of exposure, as well as cognitive and behavioral consequences of multiple metal exposure, should be investigated in this population.

  5. 3D HOLOGRAM KATALOG MEBEL KOMUNITAS “PESONA BAHARI”

    Ahmad Suroso

    2017-04-01

    Full Text Available Media promosi dari waktu ke waktu semakin berkembang, dari  pembicaraan orang ke orang sampai memasuki era  digital  sesuai perkembangan teknologi saat  ini.  Dimana pada  era  digital ini  banyak bermunculan aplikasi–aplikasi yang digunakan sebagai media promosi. Dalam hal ini media yang akan dikembangkan adalah media promosi dengan 3D hologram yaitu membuat sebuah 3D hologram katalog mebel pesona bahari yang masih dalam bentuk buku atau gambar 2D yang nantinya akan menampilkan detail jenis suatu barang mebel yang akan dipromosikan. 3D hologram merupakan salah satu contoh perkembangan teknologi yang masih tergolong baru pada saat ini, dimana 3D hologram akan menampilkan bentuk barang yang menyerupai bentuk aslinya. Dengan metode pengembangan multimedia yang dikembangkan oleh sutopo yaitu concept, design, material collecting, assembly, testing, dan distribution.Animasi akan dibangun dimulai dari pengonsepan animasi sampai pada akhirnya animasi akan didisbrusikan kepada masyarakat umum yang membutuhkan. Aplikasi yang akan didistribusikan berupa aplikasi jadi dimana di dalam aplikasi tersebut berisi animasi 3D Hologram barang-barang mebel yang telah ditentukan.

  6. Quickly updatable hologram images with high performance photorefractive polymer composites

    Tsutsumi, Naoto; Kinashi, Kenji; Nonomura, Asato; Sakai, Wataru

    2012-02-01

    We present here quickly updatable hologram images using high performance photorefractive (PR) polymer composite based on poly(N-vinyl carbazole) (PVCz). PVCz is one of the pioneer materials for photoconductive polymer. PVCz/7- DCST/CzEPA/TNF (44/35/20/1 by wt) gives high diffraction efficiency of 68 % at E = 45 V/μm with fast response speed. Response speed of optical diffraction is the key parameter for real-time 3D holographic display. Key parameter for obtaining quickly updatable hologram images is to control the glass transition temperature lower enough to enhance chromophore orientation. Object image of the reflected coin surface recorded with reference beam at 532 nm (green beam) in the PR polymer composite is simultaneously reconstructed using a red probe beam at 642 nm. Instead of using coin object, object image produced by a computer was displayed on a spatial light modulator (SLM) is used as an object for hologram. Reflected object beam from a SLM interfered with reference beam on PR polymer composite to record a hologram and simultaneously reconstructed by a red probe beam. Movie produced in a computer was recorded as a realtime hologram in the PR polymer composite and simultaneously clearly reconstructed with a video rate.

  7. Phenomenological modeling of nonlinear holograms based on metallic geometric metasurfaces.

    Ye, Weimin; Li, Xin; Liu, Juan; Zhang, Shuang

    2016-10-31

    Benefiting from efficient local phase and amplitude control at the subwavelength scale, metasurfaces offer a new platform for computer generated holography with high spatial resolution. Three-dimensional and high efficient holograms have been realized by metasurfaces constituted by subwavelength meta-atoms with spatially varying geometries or orientations. Metasurfaces have been recently extended to the nonlinear optical regime to generate holographic images in harmonic generation waves. Thus far, there has been no vector field simulation of nonlinear metasurface holograms because of the tremendous computational challenge in numerically calculating the collective nonlinear responses of the large number of different subwavelength meta-atoms in a hologram. Here, we propose a general phenomenological method to model nonlinear metasurface holograms based on the assumption that every meta-atom could be described by a localized nonlinear polarizability tensor. Applied to geometric nonlinear metasurfaces, we numerically model the holographic images formed by the second-harmonic waves of different spins. We show that, in contrast to the metasurface holograms operating in the linear optical regime, the wavelength of incident fundamental light should be slightly detuned from the fundamental resonant wavelength to optimize the efficiency and quality of nonlinear holographic images. The proposed modeling provides a general method to simulate nonlinear optical devices based on metallic metasurfaces.

  8. Single-shot speckle reduction in numerical reconstruction of digitally recorded holograms.

    Hincapie, Diego; Herrera-Ramírez, Jorge; Garcia-Sucerquia, Jorge

    2015-04-15

    A single-shot method to reduce the speckle noise in the numerical reconstructions of electronically recorded holograms is presented. A recorded hologram with the dimensions N×M is split into S=T×T sub-holograms. The uncorrelated superposition of the individually reconstructed sub-holograms leads to an image with the speckle noise reduced proportionally to the 1/S law. The experimental results are presented to support the proposed methodology.

  9. 3D velocity measurements in fluid flows using multiple exposure holography

    Stanislas, M.; Rodriguez, O.; Dadi, M.; Beluche, F.

    1987-01-01

    An account is given of multiple exposure holography's application to the measurement of velocity in fluid flows. The method is nonintrusive, and yields access to the three components of the instantaneous velocity in three-dimensional domains. These characteristics render such holographic data complementary to classical LDV. Attention is given to solutions proposed for such limitations inherent in the method as the rather lengthy acquisition time; this difficulty is presently addressed by means of an automated evaluation methodology. 12 references

  10. Deformation of digital holograms for full control of focus and for extending the depth of field

    Paturzo, M; Memmolo, P; Finizio, A; Ferraro, P, E-mail: pietro.ferraro@inoa.i [CNR-Istituto Nazionale di Ottica Applicata and Istituto di Cibernetica, via Campi Flegrei 34, 80078 Pozzuoli (Italy)

    2010-02-01

    We present a new method to manage the depth of focus in holograms numerical reconstructions through an adaptive deformation of the digital holograms. We demonstrate that this technique can be applied both to Fourier and Fresnel holograms. The experimental results, in agreement with the theoretical model, are shown and commented for both these configurations.

  11. Taking Multiple Exposure Into Account Can Improve Assessment of Chemical Risks.

    Clerc, Frédéric; Bertrand, Nicolas Jean Hyacinthe; La Rocca, Bénédicte

    2017-12-15

    During work, operators may be exposed to several chemicals simultaneously. Most exposure assessment approaches only determine exposure levels for each substance individually. However, such individual-substance approaches may not correctly estimate the toxicity of 'cocktails' of chemicals, as the toxicity of a cocktail may differ from the toxicity of substances on their own. This study presents an approach that can better take into account multiple exposure when assessing chemical risks. Almost 30000 work situations, monitored between 2005 and 2014 and recorded in two French databases, were analysed using MiXie software. The algorithms employed in MiXie can identify toxicological classes associated with several substances, based on the additivity of the selected effects of each substance. The results of our retrospective analysis show that MiXie was able to identify almost 20% more potentially hazardous situations than identified using a single-substance approach. It therefore appears essential to review the ways in which multiple exposure is taken into account during risk assessment. © The Author(s) 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  12. Efficient Verification of Holograms Using Mobile Augmented Reality.

    Hartl, Andreas Daniel; Arth, Clemens; Grubert, Jens; Schmalstieg, Dieter

    2016-07-01

    Paper documents such as passports, visas and banknotes are frequently checked by inspection of security elements. In particular, optically variable devices such as holograms are important, but difficult to inspect. Augmented Reality can provide all relevant information on standard mobile devices. However, hologram verification on mobiles still takes long and provides lower accuracy than inspection by human individuals using appropriate reference information. We aim to address these drawbacks by automatic matching combined with a special parametrization of an efficient goal-oriented user interface which supports constrained navigation. We first evaluate a series of similarity measures for matching hologram patches to provide a sound basis for automatic decisions. Then a re-parametrized user interface is proposed based on observations of typical user behavior during document capture. These measures help to reduce capture time to approximately 15 s with better decisions regarding the evaluated samples than what can be achieved by untrained users.

  13. Broadband and chiral binary dielectric meta-holograms.

    Khorasaninejad, Mohammadreza; Ambrosio, Antonio; Kanhaiya, Pritpal; Capasso, Federico

    2016-05-01

    Subwavelength structured surfaces, known as meta-surfaces, hold promise for future compact and optically thin devices with versatile functionalities. By revisiting the concept of detour phase, we demonstrate high-efficiency holograms with broadband and chiral imaging functionalities. In our devices, the apertures of binary holograms are replaced by subwavelength structured microgratings. We achieve broadband operation from the visible to the near infrared and efficiency as high as 75% in the 1.0 to 1.4 μm range by compensating for the inherent dispersion of the detour phase with that of the subwavelength structure. In addition, we demonstrate chiral holograms that project different images depending on the handedness of the reference beam by incorporating a geometric phase. Our devices' compactness, lightness, and ability to produce images even at large angles have significant potential for important emerging applications such as wearable optics.

  14. Experimental method for testing diffraction properties of reflection waveguide holograms.

    Xie, Yi; Kang, Ming-Wu; Wang, Bao-Ping

    2014-07-01

    Waveguide holograms' diffraction properties include peak wavelength and diffraction efficiency, which play an important role in determining their display performance. Based on the record and reconstruction theory of reflection waveguide holograms, a novel experimental method for testing diffraction properties is introduced and analyzed in this paper, which uses a plano-convex lens optically contacted to the surface of the substrate plate of the waveguide hologram, so that the diffracted light beam can be easily detected. Then an experiment is implemented. The designed reconstruction wavelength of the test sample is 530 nm, and its diffraction efficiency is 100%. The experimental results are a peak wavelength of 527.7 nm and a diffraction efficiency of 94.1%. It is shown that the tested value corresponds well with the designed value.

  15. Replication of Holograms with Corn Syrup by Rubbing

    Mejias-Brizuela, Nildia Y.; Olivares-Pérez, Arturo; Ortiz-Gutiérrez, Mauricio

    2012-01-01

    Corn syrup films are used to replicate holograms in order to fabricate micro-structural patterns without the toxins commonly found in photosensitive salts and dyes. We use amplitude and relief masks with lithographic techniques and rubbing techniques in order to transfer holographic information to corn syrup material. Holographic diffraction patterns from holographic gratings and computer Fourier holograms fabricated with corn syrup are shown. We measured the diffraction efficiency parameter in order to characterize the film. The versatility of this material for storage information is promising. Holographic gratings achieved a diffraction efficiency of around 8.4% with an amplitude mask and 36% for a relief mask technique. Preliminary results using corn syrup as an emulsion for replicating holograms are also shown in this work.

  16. Nanometric holograms based on a topological insulator material.

    Yue, Zengji; Xue, Gaolei; Liu, Juan; Wang, Yongtian; Gu, Min

    2017-05-18

    Holography has extremely extensive applications in conventional optical instruments spanning optical microscopy and imaging, three-dimensional displays and metrology. To integrate holography with modern low-dimensional electronic devices, holograms need to be thinned to a nanometric scale. However, to keep a pronounced phase shift modulation, the thickness of holograms has been generally limited to the optical wavelength scale, which hinders their integration with ultrathin electronic devices. Here, we break this limit and achieve 60 nm holograms using a topological insulator material. We discover that nanometric topological insulator thin films act as an intrinsic optical resonant cavity due to the unequal refractive indices in their metallic surfaces and bulk. The resonant cavity leads to enhancement of phase shifts and thus the holographic imaging. Our work paves a way towards integrating holography with flat electronic devices for optical imaging, data storage and information security.

  17. Replication of Holograms with Corn Syrup by Rubbing

    Arturo Olivares-Pérez

    2012-08-01

    Full Text Available Corn syrup films are used to replicate holograms in order to fabricate micro-structural patterns without the toxins commonly found in photosensitive salts and dyes. We use amplitude and relief masks with lithographic techniques and rubbing techniques in order to transfer holographic information to corn syrup material. Holographic diffraction patterns from holographic gratings and computer Fourier holograms fabricated with corn syrup are shown. We measured the diffraction efficiency parameter in order to characterize the film. The versatility of this material for storage information is promising. Holographic gratings achieved a diffraction efficiency of around 8.4% with an amplitude mask and 36% for a relief mask technique. Preliminary results using corn syrup as an emulsion for replicating holograms are also shown in this work.

  18. Radioisotope imaging using gamma-ray shadow hologram

    Kojima, Kazuhiko; Itaya, Gensei; Hisada, Kin-ichi.

    1975-01-01

    Use of holography for the imaging of radioisotope distribution, reported by Barrett, H.H. in 1972, has been marked as a new γ-ray imaging. Generally, in optical fields, holography was often used for recording and processing three dimensional images by coherent waves such as laser beams. However, γ-rays are incoherent and are not condensed by optical lenses. So it was necessary that the holograms of incoherent sources were formed without optical lenses. A method which records the shadows of on axis zone plate with a Fresnnel diffraction pattern was used for obtaining an incoherent hologram. This method has the advantages of improved resolution and γ-ray detection efficiency, and also has a constitution of this system which is simple and economical. But, the disadvantage is, that the process consists of two steps, forming holograms and reconstructing images. The fundamental problems of γ-ray holograms and the practicabilities of γ-ray imaging of this method were discussed. In this system medical x-ray films combined with industrial intensifying screens were used as detectors, and γ-ray shadow holograms were obtained for about 3 minutes. From the shadow holograms, images were reconstructed, using a parallel laser beams, (He-Ne laser, single mode, 6328 A, 1mW). The zone plate consisted of coaxial lead rings with 10 open zones. The aperture area of this zone plate collimator was several hundreds times larger than the pinhole, so the detection efficiency, of γ-rays was improved. Using sup(99m)Tc 10 mCi as a γ-ray source, an attempt was made to image points, English characters and thyroid phantoms, and these reconstructed images were shown. An image resolution of 3-5 mm was obtained in the reconstructed image of an object at a distance of 10 cm from the collimator. (auth.)

  19. The effects of multiple UV exposures on HIV-LTR (long terminal repeat) expression

    Schreck, S.; Milton, J.; Panozzo, J.; Libertin, C.R.; Woloschak, G.E.; Loyola Univ., Maywood, IL

    1995-01-01

    Previous studies have shown that cellular stress agents such as UV radiation induce transcription from the long terminal repeat (LTR) of the human immunodeficiency virus (HIV). Using HeLa cells stably transfected with the HIV-LTR sequence, which transcriptionally drives the chloramphenicol acetyl transferase (CAT) reporter gene, we examined the effects of multiple exposures to UVC (254 nm) on HIV-LTR-CAT expression. Low doses (≤ 5 J m -2 ) had no effect on CAT expression, but up to 29-fold induction was observed with 10 J m -2 when cells were harvested 48 h after completion of the exposure. Little difference was noted in induction levels when cells were exposed to one 25 J m -2 dose, viable cells were harvested at 24 h, 48 h or 72 h, and cell lysates were assayed for CAT expression. Two sequential 12.5 J m -2 exposures, given 24 h apart, resulted in an additive effect on CAT expression; these two exposures produced CAT activity equivalent to that induced following a single 25 J m -2 dose. Our data suggest that HIV-LTR requires a specific threshold UV dose in order to elicit induction; a maximal induction dose is also evident; exposures higher than this maximal dose contribute no more to HIV-LTR induction in viable cells. (author)

  20. Polarization holograms allow highly efficient generation of complex light beams.

    Ruiz, U; Pagliusi, P; Provenzano, C; Volke-Sepúlveda, K; Cipparrone, Gabriella

    2013-03-25

    We report a viable method to generate complex beams, such as the non-diffracting Bessel and Weber beams, which relies on the encoding of amplitude information, in addition to phase and polarization, using polarization holography. The holograms are recorded in polarization sensitive films by the interference of a reference plane wave with a tailored complex beam, having orthogonal circular polarizations. The high efficiency, the intrinsic achromaticity and the simplicity of use of the polarization holograms make them competitive with respect to existing methods and attractive for several applications. Theoretical analysis, based on the Jones formalism, and experimental results are shown.

  1. Bayesian approach to analyzing holograms of colloidal particles.

    Dimiduk, Thomas G; Manoharan, Vinothan N

    2016-10-17

    We demonstrate a Bayesian approach to tracking and characterizing colloidal particles from in-line digital holograms. We model the formation of the hologram using Lorenz-Mie theory. We then use a tempered Markov-chain Monte Carlo method to sample the posterior probability distributions of the model parameters: particle position, size, and refractive index. Compared to least-squares fitting, our approach allows us to more easily incorporate prior information about the parameters and to obtain more accurate uncertainties, which are critical for both particle tracking and characterization experiments. Our approach also eliminates the need to supply accurate initial guesses for the parameters, so it requires little tuning.

  2. Sun exposure over the life course and associations with multiple sclerosis.

    Tremlett, Helen; Zhu, Feng; Ascherio, Alberto; Munger, Kassandra L

    2018-04-03

    To examine sun exposure and multiple sclerosis (MS) over the life course (ages 5-15 and 16-20 years, every 10 years thereafter). Cases with MS (n = 151) and age-matched controls (n = 235) from the Nurses' Health Study cohorts completed summer, winter, and lifetime sun exposure history questionnaires. Cumulative ambient ultraviolet (UV)-B (based on latitude, altitude, cloud cover) exposure before MS onset was expressed as tertiles. Seasonal sun exposure was defined as low vs high hours per week (summer [≤9 vs >10 h/wk]; winter [≤3 vs >4 h/wk]). Relative risks (RRs) and 95% confidence intervals (CIs) were estimated via conditional logistic regression with adjustment for body mass index, ancestry, smoking, and vitamin D supplementation. Most participants were white (98%); the mean age at MS onset was 39.5 years. Living in high (vs low) UV-B areas before MS onset was associated with a 45% lower MS risk (adjusted RR 0.55, 95% CI 0.42-0.73). Similar reduced risks (51%-52%) for medium or high exposure were observed at ages 5 to 15 years and at 5 to 15 years before MS onset (adjusted p sun exposure were associated with a lower MS risk (RR 0.45, 95% CI 0.21-0.96). Living in high ambient UV-B areas during childhood and the years leading up to MS onset was associated with a lower MS risk. High summer sun exposure in high ambient UV-B areas was also associated with a reduced risk. © 2018 American Academy of Neurology.

  3. Variations in community exposure to lahar hazards from multiple volcanoes in Washington State (USA)

    Diefenbach, Angela K.; Wood, Nathan J.; Ewert, John W.

    2015-01-01

    Understanding how communities are vulnerable to lahar hazards provides critical input for effective design and implementation of volcano hazard preparedness and mitigation strategies. Past vulnerability assessments have focused largely on hazards posed by a single volcano, even though communities and officials in many parts of the world must plan for and contend with hazards associated with multiple volcanoes. To better understand community vulnerability in regions with multiple volcanic threats, we characterize and compare variations in community exposure to lahar hazards associated with five active volcanoes in Washington State, USA—Mount Baker, Glacier Peak, Mount Rainier, Mount Adams and Mount St. Helens—each having the potential to generate catastrophic lahars that could strike communities tens of kilometers downstream. We use geospatial datasets that represent various population indicators (e.g., land cover, residents, employees, tourists) along with mapped lahar-hazard boundaries at each volcano to determine the distributions of populations within communities that occupy lahar-prone areas. We estimate that Washington lahar-hazard zones collectively contain 191,555 residents, 108,719 employees, 433 public venues that attract visitors, and 354 dependent-care facilities that house individuals that will need assistance to evacuate. We find that population exposure varies considerably across the State both in type (e.g., residential, tourist, employee) and distribution of people (e.g., urban to rural). We develop composite lahar-exposure indices to identify communities most at-risk and communities throughout the State who share common issues of vulnerability to lahar-hazards. We find that although lahars are a regional hazard that will impact communities in different ways there are commonalities in community exposure across multiple volcanoes. Results will aid emergency managers, local officials, and the public in educating at-risk populations and developing

  4. Occupation, exposure to chemicals, sensitizing agents, and risk of multiple myeloma in Sweden.

    Lope, Virginia; Pérez-Gómez, Beatriz; Aragonés, Nuria; López-Abente, Gonzalo; Gustavsson, Per; Plato, Nils; Zock, Jan-Paul; Pollán, Marina

    2008-11-01

    This study sought to identify occupations with high incidence of multiple myeloma and to investigate possible excess risk associated with occupational exposure to chemicals and sensitizing agents in Sweden. A historical cohort of 2,992,166 workers was followed up (1971--1989) through record linkage with the National Cancer and Death Registries. For each job category, age and period standardized incidence ratios and age and period adjusted relative risks of multiple myeloma were calculated using Poisson models. Exposure to chemicals and to sensitizing agents was also assessed using two job-exposure matrices. Men and women were analyzed separately. During follow-up, 3,127 and 1,282 myelomas were diagnosed in men and women, respectively. In men, excess risk was detected among working proprietors, agricultural, horticultural and forestry enterprisers, bakers and pastry cooks, dental technicians, stone cutters/carvers, and prison/reformatory officials. In women, this excess was observed among attendants in psychiatric care, metal workers, bakers and pastry cooks, and paper/paperboard product workers. Workers, particularly bakers and pastry cooks, exposed to high molecular weight sensitizing agents registered an excess risk of over 40% across the sexes. Occasional, although intense, exposure to pesticides was also associated with risk of myeloma in our cohort. Our study supports a possible etiologic role for farming and use of pesticides in myeloma risk. The high incidence found in both female and male bakers and pastry cooks has not been described previously. Further research is required to assess the influence of high molecular weight sensitizing agents on risk of multiple myeloma.

  5. Highly efficient holograms based on c-Si metasurfaces in the visible range.

    Martins, Augusto; Li, Juntao; da Mota, Achiles F; Wang, Yin; Neto, Luiz G; do Carmo, João P; Teixeira, Fernando L; Martins, Emiliano R; Borges, Ben-Hur V

    2018-04-16

    This paper reports on the first hologram in transmission mode based on a c-Si metasurface in the visible range. The hologram shows high fidelity and high efficiency, with measured transmission and diffraction efficiencies of ~65% and ~40%, respectively. Although originally designed to achieve full phase control in the range [0-2π] at 532 nm, these holograms have also performed well at 444.9 nm and 635 nm. The high tolerance to both fabrication and wavelength variations demonstrate that holograms based on c-Si metasurfaces are quite attractive for diffractive optics applications, and particularly for full-color holograms.

  6. Single-exposure two-dimensional superresolution in digital holography using a vertical cavity surface-emitting laser source array.

    Granero, Luis; Zalevsky, Zeev; Micó, Vicente

    2011-04-01

    We present a new implementation capable of producing two-dimensional (2D) superresolution (SR) imaging in a single exposure by aperture synthesis in digital lensless Fourier holography when using angular multiplexing provided by a vertical cavity surface-emitting laser source array. The system performs the recording in a single CCD snapshot of a multiplexed hologram coming from the incoherent addition of multiple subholograms, where each contains information about a different 2D spatial frequency band of the object's spectrum. Thus, a set of nonoverlapping bandpass images of the input object can be recovered by Fourier transformation (FT) of the multiplexed hologram. The SR is obtained by coherent addition of the information contained in each bandpass image while generating an enlarged synthetic aperture. Experimental results demonstrate improvement in resolution and image quality.

  7. Wavelength properties of DCG holograms under the conditions of different temperature and humidity

    Liu, Yujie; Li, Wenqiang; Ding, Quanxin; Yan, Zhanjun

    2014-12-01

    Holograms recorded in dichromated gelatin (DCG) are usually sealed with a glass plate cemented with an epoxy glue to protect the holograms from moisture in the environment. An investigation of the wavelength properties of sealed DCG holograms had been carried out paying attention to holograms which were exposed to different temperature and humidity environment in this work. The investigation had revealed that (a) exposing the sealed DCG holograms to high relative humidity (RH=98%) environment or immersing them in room-temperature water for 20 hours can not affect the holograms; (b) the sealed DCG holograms can be used at temperature below 50°C without showing undue detrimental effects regarding their optical properties; (c) the peak wavelength of sealed DCG holograms can cause blue shift of several nanometers at 70°C~85°C and the velocity of blue shift is proportional to the environmental temperature; (d) the holograms can be destroyed at 100° or above. The experimental results above will be analyzed and discussed in this paper. A method to improve the stability of sealed DCG holograms is proposed: baking the sealed DCG holograms at proper temperature (e.g., 85°C in this study).

  8. Prenatal cigarette smoke exposure and early initiation of multiple substance use.

    Goldschmidt, Lidush; Cornelius, Marie D; Day, Nancy L

    2012-06-01

    Earlier studies have shown a relation between prenatal cigarette smoke exposure (PCSE) and offspring initiation of tobacco use. No prior study has examined the association between PCSE and early initiation of multiple substances (EIMS) including marijuana and alcohol in addition to tobacco. We investigated the association between PCSE and multiple substance use during adolescence. Pregnant women attending an urban prenatal clinic were selected to participate in the prospective longitudinal study based on their substance use. This study is based on the 16-year follow-up phase and consists of 579 mother-offspring dyads. The women were of lower socioeconomic status, 54% were Black, and 53% reported smoking cigarettes. 52% of the offspring were female. EIMS is a measure of the number of substances initiated prior to age 16 by the adolescents; it ranged from 0 (no initiation, N = 166) to 3 (all, N = 162). Adolescents exposed to tobacco during first trimester of gestation were 1.4 times more likely to initiate multiple substances by age 16 than the nonexposed group. PCSE was a significant predictor of EIMS after controlling for other prenatal exposures, home environment, and demographic characteristics, using ordinal polytomous logistic regression. Other risk factors of EIMS were maternal and adolescent depression, less strict and less involved parenting, offspring attention problems, and lack of participation in a youth club. There is a significant relation between PCSE and adolescent's EIMS.

  9. Cumulative health risk assessment: integrated approaches for multiple contaminants, exposures, and effects

    Rice, Glenn; Teuschler, Linda; MacDonel, Margaret; Butler, Jim; Finster, Molly; Hertzberg, Rick; Harou, Lynne

    2007-01-01

    Available in abstract form only. Full text of publication follows: As information about environmental contamination has increased in recent years, so has public interest in the combined effects of multiple contaminants. This interest has been highlighted by recent tragedies such as the World Trade Center disaster and hurricane Katrina. In fact, assessing multiple contaminants, exposures, and effects has long been an issue for contaminated sites, including U.S. Department of Energy (DOE) legacy waste sites. Local citizens have explicitly asked the federal government to account for cumulative risks, with contaminants moving offsite via groundwater flow, surface runoff, and air dispersal being a common emphasis. Multiple exposures range from ingestion and inhalation to dermal absorption and external gamma irradiation. Three types of concerns can lead to cumulative assessments: (1) specific sources or releases - e.g., industrial facilities or accidental discharges; (2) contaminant levels - in environmental media or human tissues; and (3) elevated rates of disease - e.g., asthma or cancer. The specific initiator frames the assessment strategy, including a determination of appropriate models to be used. Approaches are being developed to better integrate a variety of data, extending from environmental to internal co-location of contaminants and combined effects, to support more practical assessments of cumulative health risks. (authors)

  10. Improving the reconstruction quality with extension and apodization of the digital hologram

    Zhang Yancao; Zhao Jianlin; Fan Qi; Zhang Wei; Yang Sheng

    2009-01-01

    To suppress the aperture diffraction and spectral leakage effects in the reconstruction process of the digital hologram and to maintain the original information recorded in the hologram, a novel reconstruction method based on extension and apodization of the digital hologram is presented, by which the original hologram can be extended by filling the average intensity values of the boundary, and the extended hologram is apodized by use of the constructed window function. As a sample, the digital hologram of the static particle field is recorded and numerically extended and then apodized with the appointed window. Finally, an unabridged and clear digital holographic image is reconstructed from the extended and apodized hologram. The experimental results confirm that this method cannot only eliminate the black-and-white diffraction fringes in the reconstructed image, but also attain the unabridged image with high quality.

  11. Exposure to Community Violence and Sexual Behaviors Among African American Youth: Testing Multiple Pathways.

    Voisin, Dexter R; Hotton, Anna; Neilands, Torsten

    2018-01-01

    African American youth bear a disproportionate burden of sexually transmitted infections. A growing number of studies document that youth exposure to community violence and sexual behaviors are highly correlated. Despite such growing evidence, only a few studies have empirically tested conceptually driven pathways that may account for such relationships. This study seeks to address that gap by exploring multiple pathways linking exposure to community violence and youth sexual behaviors. Using an existing sample of 563 African American youth attending high school, we examined whether possible links between exposure to community violence and sexual activity, sexual risk behaviors were mediated by aggression, low student-teacher connectedness, and negative peer norms. Major findings indicated indirect relationships between exposures to community violence and both sexual activity and risky sex, mediated by aggression and negative peer norms with no significant differences based on gender or socioeconomic status. Overall findings also indicated a significant indirect effect of aggression to risky sex via negative peer norms and from community violence to risky peer norms via aggression. By illuminating ways that community violence, aggression, peer norms, and sexual behaviors are dynamically interrelated, these findings have significant implications for future research and intervention initiatives aimed at addressing the different pathways.

  12. Exposure to electromagnetic fields aboard high-speed electric multiple unit trains.

    Niu, D; Zhu, F; Qiu, R; Niu, Q

    2016-01-01

    High-speed electric multiple unit (EMU) trains generate high-frequency electric fields, low-frequency magnetic fields, and high-frequency wideband electromagnetic emissions when running. Potential human health concerns arise because the electromagnetic disturbances are transmitted mainly into the car body from windows, and from there to passengers and train staff. The transmission amount and amplitude distribution characteristics that dominate electromagnetic field emission need to be studied, and the exposure level of electromagnetic field emission to humans should be measured. We conducted a series of tests of the on board electromagnetic field distribution on several high-speed railway lines. While results showed that exposure was within permitted levels, the possibility of long-term health effects should be investigated.

  13. Interferometric key readable security holograms with secrete-codes

    2Department of Applied Physics, Guru Jambheshwar University of Science & Technology,. Hisar 125 001, India. *E-mail: aka1945@rediffmail.com. MS received 21 ... A new method is described to create secrete-codes in the security holograms for enhancing ... ing, or falsification of the valuable products and documents.

  14. Interferometric key readable security holograms with secrete-codes

    A new method is described to create secrete-codes in the security holograms for enhancing their anti-counterfeiting characteristics. ... Scientific Instruments Organisation, Sector 30, Chandigarh 160 030, India; Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125 001, India ...

  15. Inkjet printing of transparent sol-gel computer generated holograms

    Yakovlev, A.; Pidko, E.A.; Vinogradov, A.

    2016-01-01

    In this paper we report for the first time a method for the production of transparent computer generated holograms by desktop inkjet printing. Here we demonstrate a methodology suitable for the development of a practical approach towards fabrication of diffraction patterns using a desktop inkjet

  16. Fast generation of computer-generated holograms using wavelet shrinkage.

    Shimobaba, Tomoyoshi; Ito, Tomoyoshi

    2017-01-09

    Computer-generated holograms (CGHs) are generated by superimposing complex amplitudes emitted from a number of object points. However, this superposition process remains very time-consuming even when using the latest computers. We propose a fast calculation algorithm for CGHs that uses a wavelet shrinkage method, eliminating small wavelet coefficient values to express approximated complex amplitudes using only a few representative wavelet coefficients.

  17. One-Step Real-Image Reflection Holograms

    Buah-Bassuah, Paul K.; Vannoni, Maurizio; Molesini, Giuseppe

    2007-01-01

    A holographic process is presented where the object is made of the real image produced by a two-mirror system. Single-step reflection hologram recording is achieved. Details of the process are given, optics concepts are outlined and demonstrative results are presented. (Contains 6 figures and 2 footnotes.)

  18. Extraction of density distributions and particle locations from hologram images

    Ikeda, Koh; Okamoto, Koji; Kato, Fumitake; Shimizu, Isao.

    1996-01-01

    In this study, the simultaneous measurement technique for three-dimensional density and three-dimensional velocity distributions was evaluated. The Holographic Particle Image Velocimetry (HPIV) was the technique to record the three-dimensional position of the tracer particle on the hologram. In the hologram, the interferogram between reference beam and particle scattering were recorded. When there were density distributions in the interrogation region, the plane optical wave may be modulated because of the difference of the refraction indices. Then, both of the plane wave modulated by density and the spherical wave by particle scatter were interfered with the reference beam, being recorded on the hologram. With reconstructing the hologram, the both of the modulated plane wave and spherical wave were reconstructed. Since the plane wave and spherical wave had low and high frequency, respectively, the plane wave was reconstructed with the low-pass filter, resulting in the information of the density distributions to be obtained. With the high-pass filter, the particle three-dimensional positions was determined, i.e., the same procedure with the original HPIV technique. In the experiment, a jet of carbon-dioxide into air with mist were measured. Both mist particle position and the fringe shift caused by the density distribution were well observed, showing the effectiveness of the proposed technique. (author)

  19. Diffraction efficiency and noise analysis of hidden image holograms

    Tamulevičius, Sigitas; Andrulevičius, Mindaugas; Puodžiukynas, Linas

    2017-01-01

    recorded in a photoresist layer spin-coated on glass substrates applying laser interference lithography technique. Both analogue and digital analysis approaches showed the similar results thus confirming the appropriateness of the used analysis methods. It was found that holograms recorded at higher laser...

  20. Accounting for multiple climate components when estimating climate change exposure and velocity

    Nadeau, Christopher P.; Fuller, Angela K.

    2015-01-01

    The effect of anthropogenic climate change on organisms will likely be related to climate change exposure and velocity at local and regional scales. However, common methods to estimate climate change exposure and velocity ignore important components of climate that are known to affect the ecology and evolution of organisms.We develop a novel index of climate change (climate overlap) that simultaneously estimates changes in the means, variation and correlation between multiple weather variables. Specifically, we estimate the overlap between multivariate normal probability distributions representing historical and current or projected future climates. We provide methods for estimating the statistical significance of climate overlap values and methods to estimate velocity using climate overlap.We show that climates have changed significantly across 80% of the continental United States in the last 32 years and that much of this change is due to changes in the variation and correlation between weather variables (two statistics that are rarely incorporated into climate change studies). We also show that projected future temperatures are predicted to be locally novel (using climate overlap compared to 1·4 km yr−1 when estimated using traditional methods.Our results suggest that accounting for changes in the means, variation and correlation between multiple weather variables can dramatically affect estimates of climate change exposure and velocity. These climate components are known to affect the ecology and evolution of organisms, but are ignored by most measures of climate change. We conclude with a set of future directions and recommend future work to determine which measures of climate change exposure and velocity are most related to biological responses to climate change.

  1. Temporal Assessment of the Impact of Exposure to Cow Feces in Two Watersheds by Multiple Host-Specific PCR Assays

    Exposure to feces in two watersheds with different management histories was assessed by tracking cattle feces bacterial populations using multiple host-specific PCR assays. In addition, environmental factors affecting the occurrence of these markers were identified. Each assay wa...

  2. Speckle noise reduction for computer generated holograms of objects with diffuse surfaces

    Symeonidou, Athanasia; Blinder, David; Ahar, Ayyoub; Schretter, Colas; Munteanu, Adrian; Schelkens, Peter

    2016-04-01

    Digital holography is mainly used today for metrology and microscopic imaging and is emerging as an important potential technology for future holographic television. To generate the holographic content, computer-generated holography (CGH) techniques convert geometric descriptions of a 3D scene content. To model different surface types, an accurate model of light propagation has to be considered, including for example, specular and diffuse reflection. In previous work, we proposed a fast CGH method for point cloud data using multiple wavefront recording planes, look-up tables (LUTs) and occlusion processing. This work extends our method to account for diffuse reflections, enabling rendering of deep 3D scenes in high resolution with wide viewing angle support. This is achieved by modifying the spectral response of the light propagation kernels contained by the look-up tables. However, holograms encoding diffuse reflective surfaces depict significant amounts of speckle noise, a problem inherent to holography. Hence, techniques to improve the reduce speckle noise are evaluated in this paper. Moreover, we propose as well a technique to suppress the aperture diffraction during numerical, viewdependent rendering by apodizing the hologram. Results are compared visually and in terms of their respective computational efficiency. The experiments show that by modelling diffuse reflection in the LUTs, a more realistic yet computationally efficient framework for generating high-resolution CGH is achieved.

  3. Sunlight exposure and sun sensitivity associated with disability progression in multiple sclerosis.

    D'hooghe, M B; Haentjens, P; Nagels, G; Garmyn, M; De Keyser, J

    2012-04-01

    Sunlight and vitamin D have been inversely associated with the risk of multiple sclerosis (MS). We investigated sunlight exposure and sun sensitivity in relation to disability progression in MS. We conducted a survey among persons with MS, registered by the Flemish MS society, Belgium, and stratified data according to relapsing-onset and progressive-onset MS. We used Kaplan-Meier survival and Cox proportional hazard regression analyses with time to Expanded Disability Status Scale (EDSS) 6 as outcome measure. Hazard ratios for the time from onset and from birth were calculated for the potentially predictive variables, adjusting for age at onset, gender and immunomodulatory treatment. 704 (51.3%) of the 1372 respondents had reached EDSS 6. In relapsing-onset MS, respondents reporting equal or higher levels of sun exposure than persons of the same age in the last 10 years had a decreased risk of reaching EDSS 6. In progressive-onset MS, increased sun sensitivity was associated with an increased hazard of reaching EDSS 6. The association of higher sun exposure with a better outcome in relapsing-onset MS may be explained by either a protective effect or reverse causality. Mechanisms underlying sun sensitivity might influence progression in progressive-onset MS.

  4. Exposure to predator odor influences the relative use of multiple memory systems: role of basolateral amygdala.

    Leong, Kah-Chung; Packard, Mark G

    2014-03-01

    In a dual-solution plus-maze task in which both hippocampus-dependent place learning and dorsolateral striatal-dependent response learning provide an adequate solution, the relative use of multiple memory systems can be influenced by emotional state. Specifically, pre-training peripheral or intra-basolateral (BLA) administration of anxiogenic drugs result in the predominant use of response learning. The present experiments were designed to extend these findings by examining whether exposure to a putatively ethologically valid stressor would also produce a predominant use of response learning. In experiment 1, adult male Long-Evans rats were exposed to either a predator odor (trimethylthiazoline [TMT], a component of fox feces) or distilled water prior to training in a dual-solution water plus maze task. On a probe trial 24h following task acquisition, rats previously exposed to TMT predominantly displayed response learning relative to control animals. In experiment 2, rats trained on a single-solution plus maze task that required the use of response learning displayed enhanced acquisition following pre-training TMT exposure. In experiment 3, rats exposed to TMT or distilled water were trained in the dual-solution task and received post-training intra-BLA injections of the sodium channel blocker bupivacaine (1.0% solution, 0.5 μl) or saline. Relative to control animals, rats exposed to TMT predominantly displayed response learning on the probe trial, and this effect was blocked by neural inactivation of the BLA. The findings indicate that (1) the use of dorsal striatal-dependent habit memory produced by emotional arousal generalizes from anxiogenic drug administration to a putatively ecologically valid stressor (i.e. predator odor), and (2) the BLA mediates the modulatory effect of exposure to predator odor on the relative use of multiple memory systems. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Separated reconstruction of images from ultrasonic holograms with tridimensional object by digital processing

    Son, J.H.

    1979-01-01

    Because of much attractiveness, digital reconstruction of image from ultrasonic hologram by computer has been widely studied in recent years. But the method of digital reconstruction of image is displayed in the plain only, so study is done mainly of the hologram obtained from bidimensional objects. Many applications of the ultrasonic holography such as the non-distructive testing and the ultrasonic diagnosis are mostly of the tridimensional object. In the ordinary digital reconstruction of the image from the hologram obtained from tridimensional object, a question of hidden-image problem arises, and the separated reconstruction of the image for the considered part of the object is required. In this paper, multi-diffraction by tridimensional object is assumed to have linearity, ie. superposition property by each diffraction of bidimensional objects. And a new algorithm is proposed here, namely reconstructed image for considered one of bidimensional objects in tridimensional object obtained by means of operation from the two holograms tilted in unequal angles. Such tilted holograms are obtained from the tilted linear array receivers by scanning method. That images can be reconstructed by the operation from two holograms means that the new algorithm is verified. And another new method of the transformation of hologram, that is, transformation of a hologram to arbitrarily tilted hologram, has been proved valid. The reconstructed images obtained with the method of transformation and the method of operation, are the images reconstructed from one hologram by the tridimensional object and more distinctly separated that any images mentioned above. (author)

  6. Separating twin images and locating the center of a microparticle in dense suspensions using correlations among reconstructed fields of two parallel holograms.

    Ling, Hangjian; Katz, Joseph

    2014-09-20

    This paper deals with two issues affecting the application of digital holographic microscopy (DHM) for measuring the spatial distribution of particles in a dense suspension, namely discriminating between real and virtual images and accurate detection of the particle center. Previous methods to separate real and virtual fields have involved applications of multiple phase-shifted holograms, combining reconstructed fields of multiple axially displaced holograms, and analysis of intensity distributions of weakly scattering objects. Here, we introduce a simple approach based on simultaneously recording two in-line holograms, whose planes are separated by a short distance from each other. This distance is chosen to be longer than the elongated trace of the particle. During reconstruction, the real images overlap, whereas the virtual images are displaced by twice the distance between hologram planes. Data analysis is based on correlating the spatial intensity distributions of the two reconstructed fields to measure displacement between traces. This method has been implemented for both synthetic particles and a dense suspension of 2 μm particles. The correlation analysis readily discriminates between real and virtual images of a sample containing more than 1300 particles. Consequently, we can now implement DHM for three-dimensional tracking of particles when the hologram plane is located inside the sample volume. Spatial correlations within the same reconstructed field are also used to improve the detection of the axial location of the particle center, extending previously introduced procedures to suspensions of microscopic particles. For each cross section within a particle trace, we sum the correlations among intensity distributions in all planes located symmetrically on both sides of the section. This cumulative correlation has a sharp peak at the particle center. Using both synthetic and recorded particle fields, we show that the uncertainty in localizing the axial

  7. Generation of Binary Off-axis Digital Fresnel Hologram with Enhanced Quality

    Peter Wai Ming Tsang

    2015-06-01

    Full Text Available The emergence of high resolution printer and digital micromirror device (DMD has enabled real, off-axis holograms to be printed, or projected onto a screen. As most printers and DMD can only reproduce binary dots, the pixels in a hologram have to be truncated to 2 levels. However, direct binarizing a hologram will lead to severe degradation on its reconstructed image. In this paper, a method for generating binary off-axis digital Fresnel hologram is reported. A hologram generated with the proposed method is referred to as the "Enhanced Sampled Binary Hologram" (ESBH. The reconstructed image of the ESBH is superior in visual quality as compare with the one obtained with existing technique, and also resistant to noise contamination.

  8. An approach for automated analysis of particle holograms

    Stanton, A. C.; Caulfield, H. J.; Stewart, G. W.

    1984-01-01

    A simple method for analyzing droplet holograms is proposed that is readily adaptable to automation using modern image digitizers and analyzers for determination of the number, location, and size distributions of spherical or nearly spherical droplets. The method determines these parameters by finding the spatial location of best focus of the droplet images. With this location known, the particle size may be determined by direct measurement of image area in the focal plane. Particle velocity and trajectory may be determined by comparison of image locations at different instants in time. The method is tested by analyzing digitized images from a reconstructed in-line hologram, and the results show that the method is more accurate than a time-consuming plane-by-plane search for sharpest focus.

  9. Orthoscopic real-image display of digital holograms.

    Makowski, P L; Kozacki, T; Zaperty, W

    2017-10-01

    We present a practical solution for the long-standing problem of depth inversion in real-image holographic display of digital holograms. It relies on a field lens inserted in front of the spatial light modulator device addressed by a properly processed hologram. The processing algorithm accounts for pixel size and wavelength mismatch between capture and display devices in a way that prevents image deformation. Complete images of large dimensions are observable from one position with a naked eye. We demonstrate the method experimentally on a 10-cm-long 3D object using a single full-HD spatial light modulator, but it can supplement most holographic displays designed to form a real image, including circular wide angle configurations.

  10. Reconstruction dynamics of recorded holograms in photochromic glass

    Mihailescu, Mona; Pavel, Eugen; Nicolae, Vasile B.

    2011-06-20

    We have investigated the dynamics of the record-erase process of holograms in photochromic glass using continuum Nd:YVO{sub 4} laser radiation ({lambda}=532 nm). A bidimensional microgrid pattern was formed and visualized in photochromic glass, and its diffraction efficiency decay versus time (during reconstruction step) gave us information (D, {Delta}n) about the diffusion process inside the material. The recording and reconstruction processes were carried out in an off-axis setup, and the images of the reconstructed object were recorded by a CCD camera. Measurements realized on reconstructed object images using holograms recorded at a different incident power laser have shown a two-stage process involved in silver atom kinetics.

  11. Design and visualization of synthetic holograms for security applications

    Škeren, M; Nývlt, M; Svoboda, J

    2013-01-01

    In this paper we present a software for the design and visualization of holographic elements containing full scale of visual effects. It enables to simulate an observation of the holographic elements under general conditions including different light sources with various spectral and coherence properties and various geometries of reconstruction. Furthermore, recent technologies offer interesting possibilities for the 3D visualization such as the 3D techniques based on shutter or polarization glasses, anaglyphs, etc. The presented software is compatible with the mentioned techniques and enables an application of the 3D hardware tools for visualization. The software package can be used not only for visualization of the existing designs, but also for a fine tuning of the spatial, kinetic, and color properties of the hologram. Moreover, the holograms containing all types of the 3D effects, general color mixing, kinetic behavior, diffractive cryptograms, etc. can be translated using the software directly to a high resolution micro-structure.

  12. End-to-end learning for digital hologram reconstruction

    Xu, Zhimin; Zuo, Si; Lam, Edmund Y.

    2018-02-01

    Digital holography is a well-known method to perform three-dimensional imaging by recording the light wavefront information originating from the object. Not only the intensity, but also the phase distribution of the wavefront can then be computed from the recorded hologram in the numerical reconstruction process. However, the reconstructions via the traditional methods suffer from various artifacts caused by twin-image, zero-order term, and noise from image sensors. Here we demonstrate that an end-to-end deep neural network (DNN) can learn to perform both intensity and phase recovery directly from an intensity-only hologram. We experimentally show that the artifacts can be effectively suppressed. Meanwhile, our network doesn't need any preprocessing for initialization, and is comparably fast to train and test, in comparison with the recently published learning-based method. In addition, we validate that the performance improvement can be achieved by introducing a prior on sparsity.

  13. Highly efficient electron vortex beams generated by nanofabricated phase holograms

    Grillo, Vincenzo, E-mail: vincenzo.grillo@nano.cnr.it [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); CNR-IMEM Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Carlo Gazzadi, Gian [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Karimi, Ebrahim [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Mafakheri, Erfan [Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W. [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Frabboni, Stefano [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy)

    2014-01-27

    We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science.

  14. Highly efficient electron vortex beams generated by nanofabricated phase holograms

    Grillo, Vincenzo; Carlo Gazzadi, Gian; Karimi, Ebrahim; Mafakheri, Erfan; Boyd, Robert W.; Frabboni, Stefano

    2014-01-01

    We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science

  15. Sequential Exposure of Bortezomib and Vorinostat is Synergistic in Multiple Myeloma Cells

    Nanavati, Charvi; Mager, Donald E.

    2018-01-01

    Purpose To examine the combination of bortezomib and vorinostat in multiple myeloma cells (U266) and xenografts, and to assess the nature of their potential interactions with semi-mechanistic pharmacodynamic models and biomarkers. Methods U266 proliferation was examined for a range of bortezomib and vorinostat exposure times and concentrations (alone and in combination). A non-competitive interaction model was used with interaction parameters that reflect the nature of drug interactions after simultaneous and sequential exposures. p21 and cleaved PARP were measured using immunoblotting to assess critical biomarker dynamics. For xenografts, data were extracted from literature and modeled with a PK/PD model with an interaction parameter. Results Estimated model parameters for simultaneous in vitro and xenograft treatments suggested additive drug effects. The sequence of bortezomib preincubation for 24 hours, followed by vorinostat for 24 hours, resulted in an estimated interaction term significantly less than 1, suggesting synergistic effects. p21 and cleaved PARP were also up-regulated the most in this sequence. Conclusions Semi-mechanistic pharmacodynamic modeling suggests synergistic pharmacodynamic interactions for the sequential administration of bortezomib followed by vorinostat. Increased p21 and cleaved PARP expression can potentially explain mechanisms of their enhanced effects, which require further PK/PD systems analysis to suggest an optimal dosing regimen. PMID:28101809

  16. Exposure to multiple cholinergic pesticides impairs olfactory learning and memory in honeybees.

    Williamson, Sally M; Wright, Geraldine A

    2013-05-15

    Pesticides are important agricultural tools often used in combination to avoid resistance in target pest species, but there is growing concern that their widespread use contributes to the decline of pollinator populations. Pollinators perform sophisticated behaviours while foraging that require them to learn and remember floral traits associated with food, but we know relatively little about the way that combined exposure to multiple pesticides affects neural function and behaviour. The experiments reported here show that prolonged exposure to field-realistic concentrations of the neonicotinoid imidacloprid and the organophosphate acetylcholinesterase inhibitor coumaphos and their combination impairs olfactory learning and memory formation in the honeybee. Using a method for classical conditioning of proboscis extension, honeybees were trained in either a massed or spaced conditioning protocol to examine how these pesticides affected performance during learning and short- and long-term memory tasks. We found that bees exposed to imidacloprid, coumaphos, or a combination of these compounds, were less likely to express conditioned proboscis extension towards an odor associated with reward. Bees exposed to imidacloprid were less likely to form a long-term memory, whereas bees exposed to coumaphos were only less likely to respond during the short-term memory test after massed conditioning. Imidacloprid, coumaphos and a combination of the two compounds impaired the bees' ability to differentiate the conditioned odour from a novel odour during the memory test. Our results demonstrate that exposure to sublethal doses of combined cholinergic pesticides significantly impairs important behaviours involved in foraging, implying that pollinator population decline could be the result of a failure of neural function of bees exposed to pesticides in agricultural landscapes.

  17. Extraction of density distributions and particle locations from hologram images

    Okamoto, Koji; Ikeda, Koh; Madarame, Haruki [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    In this study, the simultaneous measurement technique for three-dimensional density and three-dimensional velocity distributions was evaluated. The Holographic Particle Image Velocimetry (HPIV) was the technique to record the three-dimensional position of the tracer particle on the hologram. When there were density distributions in the interrogation region, the plane optical wave may be modulated because of the difference of the refraction indices. Then, both of the plane wave modulated by density and the spherical wave by particle scatter were interfered with the reference beam, being recorded on the hologram. With reconstructing the hologram, the both of the modulated plane wave and spherical wave were reconstructed. Since the plane wave and spherical wave had low and high frequency, respectively, the two information could be separated using low-pass and high-pass filter. In the experiment, a jet of carbon-dioxide into air with mist were measured. Both mist particle position and the fringe shift caused by the density distribution were well observed, showing the effectiveness of the proposed technique. (author)

  18. Preliminary study of visual effect of multiplex hologram

    Fu, Huaiping; Xiong, Bingheng; Yang, Hong; Zhang, Xueguo

    2004-06-01

    The process of any movement of real object can be recorded and displayed by a multiplex holographic stereogram. An embossing multiplex holographic stereogram and a multiplex rainbow holographic stereogram have been made by us, the multiplex rainbow holographic stereogram reconstructs the dynamic 2D line drawing of speech organs, the embossing multiplex holographic stereogram reconstructs the process of an old man drinking water. In this paper, we studied the visual result of an embossing multiplex holographic stereogram made with 80 films of 2-D pictures. Forty-eight persons of aged from 13 to 67 were asked to see the hologram and then to answer some questions about the feeling of viewing. The results indicate that this kind of holograms could be accepted by human visual sense organ without any problem. This paper also discusses visual effect of the multiplex holography stereograms base on visual perceptual psychology. It is open out that the planar multiplex holograms can be recorded and present the movement of real animal and object. Not only have the human visual perceptual constancy for shape, just as that size, color, etc... but also have visual perceptual constancy for binocular parallax.

  19. Memory as a hologram: an analysis of learning and recall.

    Franklin, Donald R J; Mewhort, D J K

    2015-03-01

    We present a holographic theory of human memory. According to the theory, a subject's vocabulary resides in a dynamic distributed representation-a hologram. Studying or recalling a word alters both the existing representation of that word in the hologram and all words associated with it. Recall is always prompted by a recall cue (either a start instruction or the word just recalled). Order of report is a joint function of the item and associative information residing in the hologram at the time the report is made. We apply the model to archival data involving simple free recall, learning in multitrial free recall, simple serial recall, and learning in multitrial serial recall. The model captures accuracy and order of report in both free and serial recall. It also captures learning and subjective organisation in multitrial free recall. We offer the model as an alternative to the short- and long-term account of memory postulated in the modal model. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  20. Broadband metasurface holograms: toward complete phase and amplitude engineering.

    Wang, Qiu; Zhang, Xueqian; Xu, Yuehong; Gu, Jianqiang; Li, Yanfeng; Tian, Zhen; Singh, Ranjan; Zhang, Shuang; Han, Jiaguang; Zhang, Weili

    2016-09-12

    As a revolutionary three-dimensional imaging technique, holography has attracted wide attention for its ability to photographically record a light field. However, traditional phase-only or amplitude-only modulation holograms have limited image quality and resolution to reappear both amplitude and phase information required of the objects. Recent advances in metasurfaces have shown tremendous opportunities for using a planar design of artificial meta-atoms to shape the wave front of light by optimal control of both its phase and amplitude. Inspired by the concept of designer metasurfaces, we demonstrate a novel amplitude-phase modulation hologram with simultaneous five-level amplitude modulation and eight-level phase modulation. Such a design approach seeks to turn the perceived disadvantages of the traditional phase or amplitude holograms, and thus enable enhanced performance in resolution, homogeneity of amplitude distribution, precision, and signal-to-noise ratio. In particular, the unique holographic approach exhibits broadband characteristics. The method introduced here delivers more degrees of freedom, and allows for encoding highly complex information into designer metasurfaces, thus having the potential to drive next-generation technological breakthroughs in holography.

  1. Volume Holograms in Photopolymers: Comparison between Analytical and Rigorous Theories

    Gallego, Sergi; Neipp, Cristian; Estepa, Luis A.; Ortuño, Manuel; Márquez, Andrés; Francés, Jorge; Pascual, Inmaculada; Beléndez, Augusto

    2012-01-01

    There is no doubt that the concept of volume holography has led to an incredibly great amount of scientific research and technological applications. One of these applications is the use of volume holograms as optical memories, and in particular, the use of a photosensitive medium like a photopolymeric material to record information in all its volume. In this work we analyze the applicability of Kogelnik’s Coupled Wave theory to the study of volume holograms recorded in photopolymers. Some of the theoretical models in the literature describing the mechanism of hologram formation in photopolymer materials use Kogelnik’s theory to analyze the gratings recorded in photopolymeric materials. If Kogelnik’s theory cannot be applied is necessary to use a more general Coupled Wave theory (CW) or the Rigorous Coupled Wave theory (RCW). The RCW does not incorporate any approximation and thus, since it is rigorous, permits judging the accurateness of the approximations included in Kogelnik’s and CW theories. In this article, a comparison between the predictions of the three theories for phase transmission diffraction gratings is carried out. We have demonstrated the agreement in the prediction of CW and RCW and the validity of Kogelnik’s theory only for gratings with spatial frequencies higher than 500 lines/mm for the usual values of the refractive index modulations obtained in photopolymers.

  2. Volume Holograms in Photopolymers: Comparison between Analytical and Rigorous Theories

    Augusto Beléndez

    2012-08-01

    Full Text Available There is no doubt that the concept of volume holography has led to an incredibly great amount of scientific research and technological applications. One of these applications is the use of volume holograms as optical memories, and in particular, the use of a photosensitive medium like a photopolymeric material to record information in all its volume. In this work we analyze the applicability of Kogelnik’s Coupled Wave theory to the study of volume holograms recorded in photopolymers. Some of the theoretical models in the literature describing the mechanism of hologram formation in photopolymer materials use Kogelnik’s theory to analyze the gratings recorded in photopolymeric materials. If Kogelnik’s theory cannot be applied is necessary to use a more general Coupled Wave theory (CW or the Rigorous Coupled Wave theory (RCW. The RCW does not incorporate any approximation and thus, since it is rigorous, permits judging the accurateness of the approximations included in Kogelnik’s and CW theories. In this article, a comparison between the predictions of the three theories for phase transmission diffraction gratings is carried out. We have demonstrated the agreement in the prediction of CW and RCW and the validity of Kogelnik’s theory only for gratings with spatial frequencies higher than 500 lines/mm for the usual values of the refractive index modulations obtained in photopolymers.

  3. Quantum hologram of macroscopically entangled light via the mechanism of diffuse light storage

    Gerasimov, L V; Sokolov, I M; Kupriyanov, D V; Havey, M D

    2012-01-01

    In this paper, we consider a quantum memory scheme for light diffusely propagating through a spatially disordered atomic gas. A unique characteristic is enhanced trapping of the signal light pulse by quantum multiple scattering, which can be naturally integrated with the mechanism of stimulated Raman conversion into a long-lived spin coherence. Then, the quantum state of the light can be mapped onto the disordered atomic spin subsystem and can be stored in it for a relatively long time. The proposed memory scheme can be applicable for storage of the macroscopic analogue of the Ψ (−) Bell state and the prepared entangled atomic state performs its quantum hologram, which suggests the possibility of further quantum information processing. (paper)

  4. Multi-wavelengths digital holography: reconstruction, synthesis and display of holograms using adaptive transformation.

    Memmolo, P; Finizio, A; Paturzo, M; Ferraro, P; Javidi, B

    2012-05-01

    A method based on spatial transformations of multiwavelength digital holograms and the correlation matching of their numerical reconstructions is proposed, with the aim to improve superimposition of different color reconstructed images. This method is based on an adaptive affine transform of the hologram that permits management of the physical parameters of numerical reconstruction. In addition, we present a procedure to synthesize a single digital hologram in which three different colors are multiplexed. The optical reconstruction of the synthetic hologram by a spatial light modulator at one wavelength allows us to display all color features of the object, avoiding loss of details.

  5. Improvement of characteristics of diffraction gratings in Dot-matrix holograms

    ZHUMALIEV, K.M.; ISMAILOV, D.A.; ZHEENBEKOV, A.A.; SARYBAEVA, A.A.; KAZAKBAEVA, Z.M.

    2014-01-01

    This paper describes the results of research of the formation and recording of matrix hologram by Dot-matrix (dot-matrix hologram) technology on the photosensitive material of the photoresist. The principle of creating and modifying the characteristics of diffraction gratings of each pixel based on the diffraction efficiency, and recovery of colors and dynamic visual effects in dot-matrix holograms are discussed. An optical schematic diagram of the device and the process of recording dot-matrix holograms are presented. (authors)

  6. Practical algorithms for simulation and reconstruction of digital in-line holograms.

    Latychevskaia, Tatiana; Fink, Hans-Werner

    2015-03-20

    Here we present practical methods for simulation and reconstruction of in-line digital holograms recorded with plane and spherical waves. The algorithms described here are applicable to holographic imaging of an object exhibiting absorption as well as phase-shifting properties. Optimal parameters, related to distances, sampling rate, and other factors for successful simulation and reconstruction of holograms are evaluated and criteria for the achievable resolution are worked out. Moreover, we show that the numerical procedures for the reconstruction of holograms recorded with plane and spherical waves are identical under certain conditions. Experimental examples of holograms and their reconstructions are also discussed.

  7. Resolution enhancement in digital holography by self-extrapolation of holograms.

    Latychevskaia, Tatiana; Fink, Hans-Werner

    2013-03-25

    It is generally believed that the resolution in digital holography is limited by the size of the captured holographic record. Here, we present a method to circumvent this limit by self-extrapolating experimental holograms beyond the area that is actually captured. This is done by first padding the surroundings of the hologram and then conducting an iterative reconstruction procedure. The wavefront beyond the experimentally detected area is thus retrieved and the hologram reconstruction shows enhanced resolution. To demonstrate the power of this concept, we apply it to simulated as well as experimental holograms.

  8. Color selectivity of surface-plasmon holograms illuminated with white light.

    Ozaki, Miyu; Kato, Jun-ichi; Kawata, Satoshi

    2013-09-20

    By using the optical frequency dependence of surface-plasmon polaritons, color images can be reconstructed from holograms illuminated with white light. We report details on the color selectivity of the color holograms. The selectivity is tuned by the thickness of a dielectric film covering a plasmonic metal film. When the dielectric is SiO(2) and the metal is silver, the appropriate thicknesses are 25 and 55 nm, respectively. In terms of spatial color uniformity, holograms made of silver-film corrugations are better than holograms recorded on photographic film on a flat silver surface.

  9. High-efficiency holograms fixed in lithium niobate after recording using a digital fringe stabilization system.

    Arizmendi, Luis; Ambite, Emilio J

    2012-02-20

    We used a digital feedback control loop system to produce reproducible fixed volume transmission holograms of high diffraction efficiency. Different strategies were investigated to obtain holograms of good quality and the highest refractive index modulation depth. Using this control system, we were able to record holograms with stationary fringes. Additionally to using the stationary fringe recording, a double recording-fixing schedule resulted in being the most appropriate one to produce reproducible holograms of better characteristics. This strategy is discussed and compared with other already established ones. © 2012 Optical Society of America

  10. Comparing population exposure to multiple Washington earthquake scenarios for prioritizing loss estimation studies

    Wood, Nathan J.; Ratliff, Jamie L.; Schelling, John; Weaver, Craig S.

    2014-01-01

    Scenario-based, loss-estimation studies are useful for gauging potential societal impacts from earthquakes but can be challenging to undertake in areas with multiple scenarios and jurisdictions. We present a geospatial approach using various population data for comparing earthquake scenarios and jurisdictions to help emergency managers prioritize where to focus limited resources on data development and loss-estimation studies. Using 20 earthquake scenarios developed for the State of Washington (USA), we demonstrate how a population-exposure analysis across multiple jurisdictions based on Modified Mercalli Intensity (MMI) classes helps emergency managers understand and communicate where potential loss of life may be concentrated and where impacts may be more related to quality of life. Results indicate that certain well-known scenarios may directly impact the greatest number of people, whereas other, potentially lesser-known, scenarios impact fewer people but consequences could be more severe. The use of economic data to profile each jurisdiction’s workforce in earthquake hazard zones also provides additional insight on at-risk populations. This approach can serve as a first step in understanding societal impacts of earthquakes and helping practitioners to efficiently use their limited risk-reduction resources.

  11. The multiple stressor effect in zebrafish embryos from simultaneous exposure to ionising radiation and cadmium

    Ng, C Y P; Choi, V W Y; Lam, A C L; Yu, K N; Cheng, S H

    2013-01-01

    Living organisms are exposed to a mixture of environmental stressors, and the resultant effects are referred to as multiple stressor effects. In the present work, we studied the multiple stressor effect in embryos of the zebrafish (Danio rerio) from simultaneous exposure to ionising radiation (alpha particles) and cadmium through quantification of apoptotic signals at 24 h postfertilisation (hpf) revealed by vital dye acridine orange staining. For each set of experiments, 32–40 dechorionated embryos were deployed, which were divided into four groups each having 8–10 embryos. The four groups of embryos were referred to as (1) the control group (C), which received no further treatments after dechorionation; (2) the Cd-dosed and irradiated group (CdIr), which was exposed to 100 μM Cd from 5 to 24 hpf, and also received about 4.4 mGy from alpha particles at 5 hpf; (3) the irradiated group (Ir), which received about 4.4 mGy from alpha particles at 5 hpf; and (4) the Cd-dosed group (Cd), which was exposed to 100 μM Cd from 5 to 24 hpf. In general, the CdIr, Ir and Cd groups had more apoptotic signals than the C group. Within the 12 sets of experimental results, two showed significant synergistic effects, one showed a weakly synergistic effect and nine showed additive effects. The multiple stressor effect of 100 μM Cd with ∼4.4 mGy alpha-particle radiation resulted in an additive or synergistic effect, but no antagonistic effect. The failure to identify significant synergistic effects for some sets of data, and thus their subsequent classification as additive effects, might be a result of the relatively small magnitude of the synergistic effects. The results showed that the radiation risk could be perturbed by another environmental stressor such as a heavy metal, and as such a realistic human radiation risk assessment should in general take into account the multiple stressor effects. (paper)

  12. Hierarchical sampling of multiple strata: an innovative technique in exposure characterization

    Ericson, J.E.; Gonzalez, Elisabeth J.

    2003-01-01

    Sampling of multiple strata, or hierarchical sampling of various exposure sources and activity areas, has been tested and is suggested as a method to sample (or to locate) areas with a high prevalence of elevated blood lead in children. Hierarchical sampling was devised to supplement traditional soil lead sampling of a single stratum, either residential or fixed point source, using a multistep strategy. Blood lead (n=1141) and soil lead (n=378) data collected under the USEPA/UCI Tijuana Lead Project (1996-1999) were analyzed to evaluate the usefulness of sampling soil lead from background sites, schools and parks, point sources, and residences. Results revealed that industrial emissions have been a contributing factor to soil lead contamination in Tijuana. At the regional level, point source soil lead was associated with mean blood lead levels and concurrent high background, and point source soil lead levels were predictive of a high percentage of subjects with blood lead equal to or greater than 10 μg/dL (pe 10). Significant relationships were observed between mean blood lead level and fixed point source soil lead (r=0.93; P 2 =0.72 using a quadratic model) and between residential soil lead and fixed point source soil lead (r=0.90; P 2 =0.86 using a cubic model). This study suggests that point sources alone are not sufficient for predicting the relative risk of exposure to lead in the urban environment. These findings will be useful in defining regions for targeted or universal soil lead sampling by site type. Point sources have been observed to be predictive of mean blood lead at the regional level; however, this relationship alone was not sufficient to predict pe 10. It is concluded that when apparently undisturbed sites reveal high soil lead levels in addition to local point sources, dispersion of lead is widespread and will be associated with a high prevalence of elevated blood lead in children. Multiple strata sampling was shown to be useful in

  13. Narrative exposure therapy: an evidence-based treatment for multiple and complex trauma

    Ruud A. Jongedijk

    2014-12-01

    Full Text Available Narrative exposure therapy (NET is a recently developed, short-term treatment for patients with a posttraumatic stress disorder (PTSD as a result of multiple trauma. NET can be applied very successfully in patients with complex trauma complaints (Jongedijk, 2014; Schauer, Neuner, & Elbert, 2011.An important feature of NET is that trauma processing is never an isolated event but is always embedded in the context of a traumatic event and in the life history as a whole. At the start, the lifeline is laid. The lifeline is made up of a rope, with flowers (happy events, stones (traumatic events, sometimes candles (grief, or recently also sticks for aggressive acts (NET for offenders; see Stenmark, Cuneyt Guzey, Elbert, & Holen, 2014. These symbols are laid down along the rope, in chronological order. Subsequently, in the subsequent therapy sessions the lifeline is processed in chronological order, giving attention to all the important events a person has experienced in his or her life, both the adverse as well as the pleasurable ones. The narration ends with a written testimony.To date, there is good evidence NET is effective in the treatment of PTSD patients, with support from 18 RCTs (N=950. For culturally diverse populations, NET is recommended as the most evidence-based trauma treatment, besides culturally adapted CBT. NET has been investigated in different populations in Africa, Europe, and Asia. In Asia, research has been carried out in Sri Lanka as well as in China. In China, NET was conducted and investigated with survivors of the Sichuan earthquake (Zang, Hunt, & Cox, 2013, 2014. NET is understandable, even appealing and also supportive for patients with multiple trauma. In this presentation, the treatment principles and the practice of NET will be explained.

  14. A physiologically based pharmacokinetic (PB/PK) model for multiple exposure routes for soman in multiple species

    Sweeney, R.E.; Langenberg, J.P.; Maxwell, D.M.

    2006-01-01

    A physiologically based pharmacokinetic (PB/PK) model has been developed in advanced computer simulation language (ACSL) to describe blood and tissue concentration-time profiles of the C(±)P(-) stereoisomers of soman after inhalation, subcutaneous and intravenous exposures at low (0.8-1.0 × LD50),

  15. The complete book of holograms how they work and how to make them

    Kasper, Joseph Emil

    2001-01-01

    Clear, thorough account, without complicated mathematics, explains the two models of holography - the geometric and the zone plate - and different types of holograms, including transmission, reflection, phase, projection, rainbow, and multiplex. They also show basic setups for making holograms and provide step-by-step instructions so readers can make their own.

  16. Holographic memory system based on projection recording of computer-generated 1D Fourier holograms.

    Betin, A Yu; Bobrinev, V I; Donchenko, S S; Odinokov, S B; Evtikhiev, N N; Starikov, R S; Starikov, S N; Zlokazov, E Yu

    2014-10-01

    Utilization of computer generation of holographic structures significantly simplifies the optical scheme that is used to record the microholograms in a holographic memory record system. Also digital holographic synthesis allows to account the nonlinear errors of the record system to improve the microholograms quality. The multiplexed record of holograms is a widespread technique to increase the data record density. In this article we represent the holographic memory system based on digital synthesis of amplitude one-dimensional (1D) Fourier transform holograms and the multiplexed record of these holograms onto the holographic carrier using optical projection scheme. 1D Fourier transform holograms are very sensitive to orientation of the anamorphic optical element (cylindrical lens) that is required for encoded data object reconstruction. The multiplex record of several holograms with different orientation in an optical projection scheme allowed reconstruction of the data object from each hologram by rotating the cylindrical lens on the corresponding angle. Also, we discuss two optical schemes for the recorded holograms readout: a full-page readout system and line-by-line readout system. We consider the benefits of both systems and present the results of experimental modeling of 1D Fourier holograms nonmultiplex and multiplex record and reconstruction.

  17. Construction and performance of the scanning and measuring machine HOLMES used for bubble chamber holograms

    Drevermann, H.; Geissler, K.K.; Johansson, K.E.

    1985-01-01

    The construction and performance of the scanning and measuring machine HOLMES are described. It has been used to analyse in-line holograms taken with the small bubble chamber HOBC. A total of 8000 holograms has up to now been analysed on HOLMES. (orig.)

  18. A Scanning Hologram Recorded by Phase Conjugate Property of Nonlinear Crystals

    Zi-Liang, Ping; Dalsgaard, Erik

    1996-01-01

    A methode of recording a scanning hologram with phase conjugate property of nonlinear crystal is provided. The principle of recording, setup and experiments are given.......A methode of recording a scanning hologram with phase conjugate property of nonlinear crystal is provided. The principle of recording, setup and experiments are given....

  19. Fast Extended Depth-of-Field Reconstruction for Complex Holograms Using Block Partitioned Entropy Minimization

    Peter Wai Ming Tsang

    2018-05-01

    Full Text Available Optical scanning holography (OSH is a powerful and effective method for capturing the complex hologram of a three-dimensional (3-D scene. Such captured complex hologram is called optical scanned hologram. However, reconstructing a focused image from an optical scanned hologram is a difficult issue, as OSH technique can be applied to acquire holograms of wide-view and complicated object scenes. Solutions developed to date are mostly computationally intensive, and in so far only reconstruction of simple object scenes have been demonstrated. In this paper we report a low complexity method for reconstructing a focused image from an optical scanned hologram that is representing a 3-D object scene. Briefly, a complex hologram is back-propagated onto regular spaced images along the axial direction, and from which a crude, blocky depth map of the object scene is computed according to non-overlapping block partitioned entropy minimization. Subsequently, the depth map is low-pass filtered to decrease the blocky distribution, and employed to reconstruct a single focused image of the object scene for extended depth of field. The method proposed here can be applied to any complex holograms such as those obtained from standard phase-shifting holography.

  20. Resemblance of the properties of superimposed volume holograms to the properties of human memory

    Orlov, V. V.

    2006-09-01

    According to current concepts in psychology, a collection of patterns stored in human memory has the property of integrity and contains new information not contained in the individual patterns. It is shown that superimposed volume holograms possess similar properties if the information in them is written by a method that excludes the appearance of crosstalk of the holograms.

  1. Influence of Disease and Patient Characteristics on Daratumumab Exposure and Clinical Outcomes in Relapsed or Refractory Multiple Myeloma

    Yan, Xiaoyu; Clemens, Pamela L; Puchalski, Thomas

    2018-01-01

    OBJECTIVE: The aim of this study was to understand the influence of disease and patient characteristics on exposure to daratumumab, an immunoglobulin Gκ (IgGκ) monoclonal antibody, and clinical outcomes in relapsed or refractory multiple myeloma (MM). PATIENTS AND METHODS: Baseline myeloma type, ...

  2. PTSD and Comorbid Disorders in a Representative Sample of Adolescents: The Risk Associated with Multiple Exposures to Potentially Traumatic Events

    Macdonald, Alexandra; Danielson, Carla Kmett; Resnick, Heidi S.; Saunders, Benjamin E.; Kilpatrick, Dean G.

    2010-01-01

    Objective: This study compared the impact of multiple exposures to potentially traumatic events (PTEs), including sexual victimization, physical victimization, and witnessed violence, on posttraumatic stress disorder (PTSD) and comorbid conditions (i.e., major depressive episode [MDE], and substance use [SUD]). Methods: Participants were a…

  3. Fabrication and characterization of one- and two-dimensional regular patterns produced employing multiple exposure holographic lithography

    Tamulevičius, S.; Jurkevičiute, A.; Armakavičius, N.

    2017-01-01

    In this paper we describe fabrication and characterization methods of two-dimensional periodic microstructures in photoresist with pitch of 1.2 urn and lattice constant 1.2-4.8 μm, formed using two-beam multiple exposure holographic lithography technique. The regular structures were recorded empl...

  4. Generation of binary holograms with a Kinect sensor for a high speed color holographic display

    Leportier, Thibault; Park, Min-Chul; Yano, Sumio; Son, Jung-Young

    2017-05-01

    The Kinect sensor is a device that enables to capture a real scene with a camera and a depth sensor. A virtual model of the scene can then be obtained with a point cloud representation. A complex hologram can then be computed. However, complex data cannot be used directly because display devices cannot handle amplitude and phase modulation at the same time. Binary holograms are commonly used since they present several advantages. Among the methods that were proposed to convert holograms into a binary format, the direct-binary search (DBS) not only gives the best performance, it also offers the possibility to choose the display parameters of the binary hologram differently than the original complex hologram. Since wavelength and reconstruction distance can be modified, compensation of chromatic aberrations can be handled. In this study, we examine the potential of DBS for RGB holographic display.

  5. Synthesis method from low-coherence digital holograms for improvement of image quality in holographic display.

    Mori, Yutaka; Nomura, Takanori

    2013-06-01

    In holographic displays, it is undesirable to observe the speckle noises with the reconstructed images. A method for improvement of reconstructed image quality by synthesizing low-coherence digital holograms is proposed. It is possible to obtain speckleless reconstruction of holograms due to low-coherence digital holography. An image sensor records low-coherence digital holograms, and the holograms are synthesized by computational calculation. Two approaches, the threshold-processing and the picking-a-peak methods, are proposed in order to reduce random noise of low-coherence digital holograms. The reconstructed image quality by the proposed methods is compared with the case of high-coherence digital holography. Quantitative evaluation is given to confirm the proposed methods. In addition, the visual evaluation by 15 people is also shown.

  6. All-dielectric meta-holograms with holographic images transforming longitudinally

    Wang, Qiu; Xu, Quan; Zhang, Xueqian; Tian, Chunxiu; Xu, Yuehong; Gu, Jianqiang; Tian, Zhen; Ouyang, Chunmei; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili

    2017-01-01

    Metasurfaces are unique subwavelength geometries capable of engineering electromagnetic waves at will, delivering new opportunities for holography. Most previous meta-holograms, so-called phase-only meta-holograms, modulate only the amplitude distribution of a virtual object, and require optimizing techniques to improve the image quality. However, the phase distribution of the reconstructed image is usually overlooked in previous studies, leading to inevitable information loss. Here, we demonstrate all-dielectric meta-holograms that allow tailoring of both the phase and amplitude distributions of virtual objects. Several longitudinal manipulations of the holographic images are theoretically and experimentally demonstrated, including shifting, stretching, and rotating, enabling a large depth of focus. Furthermore, a new meta-hologram with a three-dimensional holographic design method is demonstrated with an even enhanced depth of focus. The proposed meta-holograms offer more freedom in holographic design and open new avenues for designing complex three-dimensional holography.

  7. All-dielectric meta-holograms with holographic images transforming longitudinally

    Wang, Qiu

    2017-11-22

    Metasurfaces are unique subwavelength geometries capable of engineering electromagnetic waves at will, delivering new opportunities for holography. Most previous meta-holograms, so-called phase-only meta-holograms, modulate only the amplitude distribution of a virtual object, and require optimizing techniques to improve the image quality. However, the phase distribution of the reconstructed image is usually overlooked in previous studies, leading to inevitable information loss. Here, we demonstrate all-dielectric meta-holograms that allow tailoring of both the phase and amplitude distributions of virtual objects. Several longitudinal manipulations of the holographic images are theoretically and experimentally demonstrated, including shifting, stretching, and rotating, enabling a large depth of focus. Furthermore, a new meta-hologram with a three-dimensional holographic design method is demonstrated with an even enhanced depth of focus. The proposed meta-holograms offer more freedom in holographic design and open new avenues for designing complex three-dimensional holography.

  8. Holograms for laser diode: Single mode optical fiber coupling

    Fuhr, P. L.

    1982-01-01

    The low coupling efficiency of semiconductor laser emissions into a single mode optical fibers place a severe restriction on their use. Associated with these conventional optical coupling techniques are stringent alignment sensitivities. Using holographic elements, the coupling efficiency may be increased and the alignment sensitivity greatly reduced. Both conventional and computer methods used in the generation of the holographic couplers are described and diagrammed. The reconstruction geometries used are shown to be somewhat restrictive but substantially less rigid than their conventional optical counterparts. Single and double hologram techniques are examined concerning their respective ease of fabrication and relative merits.

  9. Optically erasable and rewritable solid-state holograms.

    Gaylord, T. K.; Rabson, T. A.; Tittel, F. K.

    1972-01-01

    Optical holographic storage in single-crystal LiNbO3 is described which can be optically erased at room temperature and then rewritten with no degradation in efficiency or writing rate. The diffraction efficiencies associated with the process are about 0.0001. Some variations from previously obtained results include a lack of threshold power density for writing, very-long-term persistence of the stored hologram, and a lack of a dependence of the diffracted intensity on the polarization of the readout beam.

  10. Automated Reduction of Data from Images and Holograms

    Lee, G. (Editor); Trolinger, James D. (Editor); Yu, Y. H. (Editor)

    1987-01-01

    Laser techniques are widely used for the diagnostics of aerodynamic flow and particle fields. The storage capability of holograms has made this technique an even more powerful. Over 60 researchers in the field of holography, particle sizing and image processing convened to discuss these topics. The research program of ten government laboratories, several universities, industry and foreign countries were presented. A number of papers on holographic interferometry with applications to fluid mechanics were given. Several papers on combustion and particle sizing, speckle velocimetry and speckle interferometry were given. A session on image processing and automated fringe data reduction techniques and the type of facilities for fringe reduction was held.

  11. Unexpected death holograms: Animitas urban appeal in Chile

    Lautaro Ojeda Ledesma

    2011-01-01

    Full Text Available This paper aims at performing an integral analysis of the relation between popular religiousness and urban space in Chilean animitas [little shrines] practices. In order to do this, we propose a multipurpose analysis scheme, holding the concept of "unexpected death hologram". This scheme puts forward three supplementary classifications: animita as a holographic subject, as a holographic object and as a holographic place. Finally, these three classifications supplemented by interviews and topologic analyses show almost all the sociospatial factors present in this practice, accounting for the urban importance that this type of popular practice has

  12. Single-exposure color digital holography

    Feng, Shaotong; Wang, Yanhui; Zhu, Zhuqing; Nie, Shouping

    2010-11-01

    In this paper, we report a method for color image reconstruction by recording only one single multi-wavelength hologram. In the recording process, three lasers of different wavelengths emitting in the red, green and blue regions are used for illuminating on the object and the object diffraction fields will arrive at the hologram plane simultaneously. Three reference beams with different spatial angles will interfere with the corresponding object diffraction fields on the hologram plane, respectively. Finally, a series of sub-holograms incoherently overlapped on the CCD to be recorded as a multi-wavelength hologram. Angular division multiplexing is employed to reference beams so that the spatial spectra of the multiple recordings will be separated in the Fourier plane. In the reconstruction process, the multi-wavelength hologram will be Fourier transformed into its Fourier plane, where the spatial spectra of different wavelengths are separated and can be easily extracted by employing frequency filtering. The extracted spectra are used to reconstruct the corresponding monochromatic complex amplitudes, which will be synthesized to reconstruct the color image. For singleexposure recording technique, it is convenient for applications on the real-time image processing fields. However, the quality of the reconstructed images is affected by speckle noise. How to improve the quality of the images needs for further research.

  13. Surimpressions naturelles et volontaires chez les surréalistes. Un regard multiple sur Paris Voluntary and natural multiple exposure among Surrealists. A manifold view on Paris

    Héloïse Pocry

    2009-10-01

    Full Text Available La surimpression photographique, simple accident technique consistant à impressionner plusieurs fois une même surface sensible, fut mise à profit par les avant-gardes photographiques des années 1920 et 1930 pour révéler les aspects insolites ou poétiques du paysage urbain et traduire les sensations démultipliées dans cet environnement. Les reflets dans les vitrines sont également pourvoyeurs de superpositions visuelles dans la ville. Les avant-gardes vont s’intéresser à ce phénomène comme une surimpression à l’état naturel, en particulier les surréalistes, portés par leur goût du hasard et de la déambulation urbaine. Surimpressions volontaires et naturelles sont deux procédés permettant de rendre compte de l’expérience multiple du passant dans le paysage urbain. La surimpression est-elle la transposition photographique de l’expérience des reflets de vitrine ? Dans quelle mesure ces deux procédés réussissent-ils à reproduire efficacement les perturbations sensitives qui peuvent assaillir le passant dans le paysage urbain ? Nous mettrons en évidence à travers un corpus de textes et de photographies principalement issu du surréalisme des années 1920 et 1930 les enjeux des surimpressions naturelles et volontaires. Nous étudierons comment elles ont été utilisées par les surréalistes parisiens pour conduire le spectateur vers une perception et une compréhension nouvelles du paysage urbain de la capitale française.Photographic multiple exposure, a simple technical accident consisting in exposing several times the same sensitized material, was capitalized on by the photographic avant-garde in the 1920s and 1930s. Their aim was to reveal unusual or poetic aspects within urban landscape and convey its multiple sensations. Reflections on windows also provide visual urban superpositions. Avant-gardists conceived of this phenomenon as a natural multiple exposure. Surrealists were particularly fond of this

  14. The Pregnancy Exposome: Multiple Environmental Exposures in the INMA-Sabadell Birth Cohort.

    Robinson, Oliver; Basagaña, Xavier; Agier, Lydiane; de Castro, Montserrat; Hernandez-Ferrer, Carles; Gonzalez, Juan R; Grimalt, Joan O; Nieuwenhuijsen, Mark; Sunyer, Jordi; Slama, Rémy; Vrijheid, Martine

    2015-09-01

    The "exposome" is defined as "the totality of human environmental exposures from conception onward, complementing the genome" and its holistic approach may advance understanding of disease etiology. We aimed to describe the correlation structure of the exposome during pregnancy to better understand the relationships between and within families of exposure and to develop analytical tools appropriate to exposome data. Estimates on 81 environmental exposures of current health concern were obtained for 728 women enrolled in The INMA (INfancia y Medio Ambiente) birth cohort, in Sabadell, Spain, using biomonitoring, geospatial modeling, remote sensors, and questionnaires. Pair-wise Pearson's and polychoric correlations were calculated and principal components were derived. The median absolute correlation across all exposures was 0.06 (5th-95th centiles, 0.01-0.54). There were strong levels of correlation within families of exposure (median = 0.45, 5th-95th centiles, 0.07-0.85). Nine exposures (11%) had a correlation higher than 0.5 with at least one exposure outside their exposure family. Effectively all the variance in the data set (99.5%) was explained by 40 principal components. Future exposome studies should interpret exposure effects in light of their correlations to other exposures. The weak to moderate correlation observed between exposure families will permit adjustment for confounding in future exposome studies.

  15. Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors

    Knapp, Roland A.; Fellers, Gary M.; Kleeman, Patrick M.; Miller, David A. W.; Vrendenburg, Vance T.; Rosenblum, Erica Bree; Briggs, Cheryl J.

    2016-01-01

    Amphibians are one of the most threatened animal groups, with 32% of species at risk for extinction. Given this imperiled status, is the disappearance of a large fraction of the Earth’s amphibians inevitable, or are some declining species more resilient than is generally assumed? We address this question in a species that is emblematic of many declining amphibians, the endangered Sierra Nevada yellow-legged frog (Rana sierrae). Based on >7,000 frog surveys conducted across Yosemite National Park over a 20-y period, we show that, after decades of decline and despite ongoing exposure to multiple stressors, including introduced fish, the recently emerged disease chytridiomycosis, and pesticides, R. sierrae abundance increased sevenfold during the study and at a rate of 11% per year. These increases occurred in hundreds of populations throughout Yosemite, providing a rare example of amphibian recovery at an ecologically relevant spatial scale. Results from a laboratory experiment indicate that these increases may be in part because of reduced frog susceptibility to chytridiomycosis. The disappearance of nonnative fish from numerous water bodies after cessation of stocking also contributed to the recovery. The large-scale increases in R. sierrae abundance that we document suggest that, when habitats are relatively intact and stressors are reduced in their importance by active management or species’ adaptive responses, declines of some amphibians may be partially reversible, at least at a regional scale. Other studies conducted over similarly large temporal and spatial scales are critically needed to provide insight and generality about the reversibility of amphibian declines at a global scale.

  16. Heart activity monitoring using 3D hologram based on smartphone.

    Thap, Tharoeun; Heewon Chung; Jinseok Lee

    2016-08-01

    In this paper, we used smartphone to obtained pulsatile signal from a fingertip by illuminating the skin tissue using flashlight and with an on-board camera to record the change of the light intensity reflected from the tissue. The pulsatile signal is produced by analyzing average green component values of the frames taken by the camera and the heart rate is estimated in real time by detecting the pulse peaks. Based on each instant obtained heartbeat, we design a heart animation that beats according to each interval of the heartbeat. At the same time, we made a simple pyramid shaped hologram from a transparent OHP film to show the heart animation acting above the smartphone screen in three-dimensional view. With this application, users can actually monitor their heart activity in 3D rather than just to see the pulsatile signal graphically. The performances were done in two different conditions: under bright and dark environments. The holograms were made based on three different materials: grey transparent film, clear transparent film, and hard black acrylic board; the grey transparent film provided better performance and we achieved satisfactory results regardless of all environments.

  17. Multiple Forms and Settings of Exposure to Violence and Values: Unique and Interactive Relationships With Antisocial Behavior in Adolescence.

    Bacchini, Dario; Affuso, Gaetana; Aquilar, Serena

    2015-10-01

    The general purpose of this study was to investigate the relationships between multiple forms and settings of exposure to violence (ETV) as well as personal values and antisocial behavior (ASB) in adolescence. The association of ETV as witness or victim in different contexts (family, school, or neighborhood) and the association of the selected values of power, universalism, and conformity with ASB were analyzed. In addition, the role of ETV in moderating the relationship between values and ASB was tested. A total of 369 adolescents participated in the study. Hierarchical multiple regression analysis was performed. Results revealed that ASB was independently affected by exposure to family violence as a victim, exposure to school violence as a witness, exposure to neighborhood violence as a witness, and by all three selected values. The associations of ASB with universalism and conformity were negative. Conversely, the association of ASB with power was positive. One interaction had statistically significant effects. Results revealed that exposure to school violence as a witness moderates the relationship between universalism and ASB. The results highlight a high percentage of explained variance by ETV and values on ASB and suggest the importance of adopting a socio-ecological framework in interpreting adolescent behavior. © The Author(s) 2014.

  18. Discrimination of holograms and real objects by pigeons (Columba livia) and humans (Homo sapiens).

    Stephan, Claudia; Steurer, Michael M; Aust, Ulrike

    2014-08-01

    The type of stimulus material employed in visual tasks is crucial to all comparative cognition research that involves object recognition. There is considerable controversy about the use of 2-dimensional stimuli and the impact that the lack of the 3rd dimension (i.e., depth) may have on animals' performance in tests for their visual and cognitive abilities. We report evidence of discrimination learning using a completely novel type of stimuli, namely, holograms. Like real objects, holograms provide full 3-dimensional shape information but they also offer many possibilities for systematically modifying the appearance of a stimulus. Hence, they provide a promising means for investigating visual perception and cognition of different species in a comparative way. We trained pigeons and humans to discriminate either between 2 real objects or between holograms of the same 2 objects, and we subsequently tested both species for the transfer of discrimination to the other presentation mode. The lack of any decrements in accuracy suggests that real objects and holograms were perceived as equivalent in both species and shows the general appropriateness of holograms as stimuli in visual tasks. A follow-up experiment involving the presentation of novel views of the training objects and holograms revealed some interspecies differences in rotational invariance, thereby confirming and extending the results of previous studies. Taken together, these results suggest that holograms may not only provide a promising tool for investigating yet unexplored issues, but their use may also lead to novel insights into some crucial aspects of comparative visual perception and categorization.

  19. Preliminary investigation of the effects of exposure to multiple health stressors using the physiological strain index

    Edwards, A

    2010-01-01

    Full Text Available stressors and various combinations of stressors. The results indicated that noise exposure caused a statistically significant increase in PSI scores. None of the results for exposure to heat alone, physical work alone or the two in combination showed a...

  20. In Vivo Lipopolysaccharide Exposure of Human Blood Leukocytes Induces Cross-Tolerance to Multiple TLR Ligands

    de Vos, Alex F.; Pater, Jennie M.; van den Pangaart, Petra S.; de Kruif, Martijn D.; van 't Veer, Cornelis; van der Poll, Tom

    2009-01-01

    In vitro and in vivo experiments in mice have shown that exposure of cells to the TLR4 ligand LPS induces tolerance toward a second exposure to LPS and induces cross-tolerance to certain other TLR ligands. Recently, we found that LPS tolerance in experimental human endotoxemia and Gram-negative

  1. Single-shot speckle reduction in numerical reconstruction of digitally recorded holograms: comment.

    Maycock, Jonathan; Hennelly, Bryan; McDonald, John

    2015-09-01

    We comment on a recent Letter by Hincapie et al. [Opt. Lett.40, 1623 (2015)], in which the authors proposed a method to reduce the speckle noise in digital holograms. This method was previously published by us in Maycock ["Improving reconstructions of digital holograms," Ph.D. thesis (National University of Ireland, 2012)] and Maycock and Hennelly [Improving Reconstructions of Digital Holograms: Speckle Reduction and Occlusions in Digital Holography (Lambert Academic, 2014)]. We also wish to highlight an important limitation of the method resulting from the superposition of different perspectives of the object/scene, which was not addressed in their Letter.

  2. Traumatic exposure and posttraumatic stress disorder among flood victims: Testing a multiple mediating model.

    Quan, Lijuan; Zhen, Rui; Yao, Benxian; Zhou, Xiao

    2017-05-01

    A total of 187 flood victims from Wuhu, a Chinese city affected most severely by a flood during July 2016, were selected to complete self-report measures of traumatic exposure, feelings of safety, fear, posttraumatic negative cognition, and posttraumatic stress disorder. The results found that traumatic exposure could directly predict posttraumatic stress disorder. Besides, traumatic exposure had indirect prediction on posttraumatic stress disorder through three ways, including a one-step path of negative self-cognition, a two-step path from feelings of safety to fear, and a three-step path from feelings of safety to negative self-cognition via fear. Implications and future directions are correspondingly discussed.

  3. Life-Stage PBPK Models for Multiple Routes of Ethanol Exposure in the Rat

    Ethanol is commonly blended with gasoline (10% ethanol) in the US, and higher ethanol concentrations are being considered. While the pharmacokinetics and toxicity of orally-ingested ethanol are widely reported, comparable work is limited for inhalation exposure (IE), particularly...

  4. Integrated pillar scatterers for speeding up classification of cell holograms.

    Lugnan, Alessio; Dambre, Joni; Bienstman, Peter

    2017-11-27

    The computational power required to classify cell holograms is a major limit to the throughput of label-free cell sorting based on digital holographic microscopy. In this work, a simple integrated photonic stage comprising a collection of silica pillar scatterers is proposed as an effective nonlinear mixing interface between the light scattered by a cell and an image sensor. The light processing provided by the photonic stage allows for the use of a simple linear classifier implemented in the electric domain and applied on a limited number of pixels. A proof-of-concept of the presented machine learning technique, which is based on the extreme learning machine (ELM) paradigm, is provided by the classification results on samples generated by 2D FDTD simulations of cells in a microfluidic channel.

  5. Characterization of the multiple drug resistance phenotype expressed by tumour cells following in vitro exposure to fractionated X-irradiation

    Hill, B.T.; McClean, S.; Hosking, L.; Shellard, S.; Dempke, W.; Whelan, R.

    1992-01-01

    The major clinical problem of the emergence of drug resistant tumor cell populations is recognized in patients previously treated with antitumor drugs and with radiotherapy. It is proposed that, although radiation-induced vascular fibrosis may limit drug delivery to the tumor, exposure to radiation may 'induce' or 'select for' drug resistance. This hypothesis was examined by establishing in vitro model systems to investigate the resistance phenotype of tumor cells following exposure to X-rays. Characteristically tumor cells surviving exposure to a series of fractions of X-irradiation are shown to have consistently expressed resistance to multiple drugs, including the Vinca alkaloids and the epipodophyllotoxins. Currently this research is aimed at determining whether distinctive resistance mechanisms operate depending on whether resistance results following drug or X-ray exposure. Initial results indicate that whilst some common mechanisms operate, drug resistant tumor cells identified following exposure to X-irradiation appear to exhibit a novel multidrug resistance phenotype. (author). 13 refs., 1 tab

  6. Media Exposure in Low-Income Preschool-Aged Children Is Associated with Multiple Measures of Self-Regulatory Behavior.

    Munzer, Tiffany G; Miller, Alison L; Peterson, Karen E; Brophy-Herb, Holly E; Horodynski, Mildred A; Contreras, Dawn; Sturza, Julie; Lumeng, Julie C; Radesky, Jenny

    2018-05-01

    Excessive screen media exposure in childhood is associated with parent-reported self-regulation difficulties. No studies have used laboratory-based or teacher-reported measures of child self-regulatory behaviors. This study examines cross-sectional associations between preschooler screen media exposure and multiple measures of self-regulatory behaviors. Preintervention data were used from 541 preschoolers in the Growing Healthy study, an obesity prevention trial (2011-2015). Screen media exposure was measured by daily screen media exposure (hr/d), television (TV) in the bedroom, frequency of background TV, and TV with meals (1 = rarely/never, 4 = frequently). Child self-regulatory behaviors were measured by the following: child ability to delay gratification, a standardized waiting paradigm; teacher-reported Social Competence and Behavior Evaluation; and parent-reported difficult temperament on the Child Behavior Questionnaire (CBQ). Multivariate regression analyses modeled screen media exposure predicting each self-regulatory measure, adjusting for child age, sex, parent age, education, marital status, income-to-needs ratio, number of adults in household, parent depressive symptoms, and sensitivity. Children were aged 4.1 years (SD = 0.5), parents were aged 29.6 years (SD = 6.8), 48% had high school education or less, and 67% were married. Daily screen media exposure and background TV were associated with weaker observed self-regulation (β: -10.30 seconds for each hr/d media, -12.63 seconds for 1-point increase, respectively). Background TV and TV with meals were associated with greater parent-reported difficult temperament (β: 0.04 and 0.05 CBQ, respectively, for 1-point increase). Greater screen media exposure had small but significant associations with weaker observed and parent-reported, but not teacher-reported, self-regulatory behaviors. Longitudinal studies are needed to determine the directionality of associations.

  7. Highly efficient volume hologram multiplexing in thick dye-doped jelly-like gelatin.

    Katarkevich, Vasili M; Rubinov, Anatoli N; Efendiev, Terlan Sh

    2014-08-01

    Dye-doped jelly-like gelatin is a thick-layer self-developing photosensitive medium that allows single and multiplexed volume phase holograms to be successfully recorded using pulsed laser radiation. In this Letter, we present a method for multiplexed recording of volume holograms in a dye-doped jelly-like gelatin, which provides significant increase in their diffraction efficiency. The method is based on the recovery of the photobleached dye molecule concentration in the hologram recording zone of gel, thanks to molecule diffusion from other unexposed gel areas. As an example, an optical recording of a multiplexed hologram consisting of three superimposed Bragg gratings with mean values of the diffraction efficiency and angular selectivity of ∼75% and ∼21', respectively, is demonstrated by using the proposed method.

  8. Compression of computer generated phase-shifting hologram sequence using AVC and HEVC

    Xing, Yafei; Pesquet-Popescu, Béatrice; Dufaux, Frederic

    2013-09-01

    With the capability of achieving twice the compression ratio of Advanced Video Coding (AVC) with similar reconstruction quality, High Efficiency Video Coding (HEVC) is expected to become the newleading technique of video coding. In order to reduce the storage and transmission burden of digital holograms, in this paper we propose to use HEVC for compressing the phase-shifting digital hologram sequences (PSDHS). By simulating phase-shifting digital holography (PSDH) interferometry, interference patterns between illuminated three dimensional( 3D) virtual objects and the stepwise phase changed reference wave are generated as digital holograms. The hologram sequences are obtained by the movement of the virtual objects and compressed by AVC and HEVC. The experimental results show that AVC and HEVC are efficient to compress PSDHS, with HEVC giving better performance. Good compression rate and reconstruction quality can be obtained with bitrate above 15000kbps.

  9. Full-color, large area, transmissive holograms enabled by multi-level diffractive optics.

    Mohammad, Nabil; Meem, Monjurul; Wan, Xiaowen; Menon, Rajesh

    2017-07-19

    We show that multi-level diffractive microstructures can enable broadband, on-axis transmissive holograms that can project complex full-color images, which are invariant to viewing angle. Compared to alternatives like metaholograms, diffractive holograms utilize much larger minimum features (>10 µm), much smaller aspect ratios (30 mm ×30 mm). We designed, fabricated and characterized holograms that encode various full-color images. Our devices demonstrate absolute transmission efficiencies of >86% across the visible spectrum from 405 nm to 633 nm (peak value of about 92%), and excellent color fidelity. Furthermore, these devices do not exhibit polarization dependence. Finally, we emphasize that our devices exhibit negligible absorption and are phase-only holograms with high diffraction efficiency.

  10. Generalized configurations of the reconstruction and hologram surface in digital holography

    Frere, C.

    1988-01-01

    Approximations are introduced for calculating the complex amplitude in holography, so that diffraction effects from curved lines and from the hologram surface are negligible. These effects are estimated. In the one-dimensional case, the calculation was made by the steady-phase method, with a weaker condition than the Fresnel condition. The one-dimensional transparency is exemplarily on straight, sinusoidal and elliptic lines while plane and cylindrical surfaces are chosen for the hologram surface. In the two-dimensional case, a numerical calculation is carried out using the fast Fourier transformation algorithm, and with a condition similar to the Fresnel condition. Compared with the transparency distribution, this method yields slightly disturbed reconstruction distributions. Inclined planes and cylindrical surfaces were chosen as hologram surfaces. The calculated complex amplitudes were encoded and materialized in a computer-supported hologram. (orig./DG) [de

  11. Data analysis of x-ray fluorescence holography by subtracting normal component from inverse hologram

    Happo, Naohisa; Hayashi, Kouichi; Hosokawa, Shinya

    2010-01-01

    X-ray fluorescence holography (XFH) is a powerful technique for determining three-dimensional local atomic arrangements around a specific fluorescing element. However, the raw experimental hologram is predominantly a mixed hologram, i.e., a mixture of hologram generated in both normal and inverse modes, which produces unreliable atomic images. In this paper, we propose a practical subtraction method of the normal component from the inverse XFH data by a Fourier transform for the calculated hologram of a model ZnTe cluster. Many spots originating from the normal components could be properly removed using a mask function, and clear atomic images were reconstructed at adequate positions of the model cluster. This method was successfully applied to the analysis of experimental ZnTe single crystal XFH data. (author)

  12. Dielectric Meta-Holograms Enabled with Dual Magnetic Resonances in Visible Light.

    Li, Zile; Kim, Inki; Zhang, Lei; Mehmood, Muhammad Q; Anwar, Muhammad S; Saleem, Murtaza; Lee, Dasol; Nam, Ki Tae; Zhang, Shuang; Luk'yanchuk, Boris; Wang, Yu; Zheng, Guoxing; Rho, Junsuk; Qiu, Cheng-Wei

    2017-09-26

    Efficient transmission-type meta-holograms have been demonstrated using high-index dielectric nanostructures based on Huygens' principle. It is crucial that the geometry size of building blocks be judiciously optimized individually for spectral overlap of electric and magnetic dipoles. In contrast, reflection-type meta-holograms using the metal/insulator/metal scheme and geometric phase can be readily achieved with high efficiency and small thickness. Here, we demonstrate a general platform for design of dual magnetic resonance based meta-holograms based on the geometric phase using silicon nanostructures that are quarter wavelength thick for visible light. Significantly, the projected holographic image can be unambiguously observed without a receiving screen even under the illumination of natural light. Within the well-developed semiconductor industry, our ultrathin magnetic resonance-based meta-holograms may have promising applications in anticounterfeiting and information security.

  13. Automatic focusing in digital holography and its application to stretched holograms.

    Memmolo, P; Distante, C; Paturzo, M; Finizio, A; Ferraro, P; Javidi, B

    2011-05-15

    The searching and recovering of the correct reconstruction distance in digital holography (DH) can be a cumbersome and subjective procedure. Here we report on an algorithm for automatically estimating the in-focus image and recovering the correct reconstruction distance for speckle holograms. We have tested the approach in determining the reconstruction distances of stretched digital holograms. Stretching a hologram with a variable elongation parameter makes it possible to change the in-focus distance of the reconstructed image. In this way, the proposed algorithm can be verified at different distances by dispensing the recording of different holograms. Experimental results are shown with the aim of demonstrating the usefulness of the proposed method, and a comparative analysis has been performed with respect to other existing algorithms developed for DH. © 2011 Optical Society of America

  14. Resistance of holograms made in Polaroid DMP128 photopolymer to ionizing radiation damage

    Golden, J.P.; Summers, G.P.; Carter, W.H.

    1988-01-01

    Because of their light weight and general wave-front-transforming ability, holograms appear potentially useful as beam correctors and collimators for diode-laser arrays in intersatellite optical data links. However, to survive in space a hologram must withstand damage from electrons and protons trapped in the Van Allen belts. We have found that holograms made with Polaroid DMP128 photopolymer on Suprasil-2 can withstand 63-MeV protons up to a total dose of 2 Mrad in (Si) and withstand /sup 60/Co gamma rays up to a total dose of 2 Mrad in (Si) without loss of diffraction efficiency. It appears that these holograms are sufficiently radiation hard for space application

  15. LightLeaves: computer controlled kinetic reflection hologram installation and a brief discussion of earlier work

    Connors Chen, Betsy

    2013-01-01

    LightLeaves is an installation combining leaf shaped, white light reflection holograms of landscape images with a special kinetic lighting device that houses a lamp and moving leaf shaped masks. The masks are controlled by an Arduino microcontroller and servomotors that position the masks in front of the illumination source of the holograms. The work is the most recent in a long series of landscapes that combine multi-hologram installations with computer controlled devices that play with the motion of the holograms, the light, sound or other elements in the work. LightLeaves was first exhibited at the Peabody Essex Museum in Salem, Massachusetts in a show titled E ye Spy: Playing with Perception .

  16. LightLeaves: computer controlled kinetic reflection hologram installation and a brief discussion of earlier work

    Connors Chen, Betsy, E-mail: acmeholo@gmail.com [ACME Holography, Somerville, Massachusetts USA 02144 (United States)

    2013-02-22

    LightLeaves is an installation combining leaf shaped, white light reflection holograms of landscape images with a special kinetic lighting device that houses a lamp and moving leaf shaped masks. The masks are controlled by an Arduino microcontroller and servomotors that position the masks in front of the illumination source of the holograms. The work is the most recent in a long series of landscapes that combine multi-hologram installations with computer controlled devices that play with the motion of the holograms, the light, sound or other elements in the work. LightLeaves was first exhibited at the Peabody Essex Museum in Salem, Massachusetts in a show titled {sup E}ye Spy: Playing with Perception{sup .}.

  17. MS Sunshine Study: Sun Exposure But Not Vitamin D Is Associated with Multiple Sclerosis Risk in Blacks and Hispanics

    Annette Langer-Gould

    2018-02-01

    Full Text Available Multiple sclerosis (MS incidence and serum 25-hydroxyvitamin D (25OHD levels vary by race/ethnicity. We examined the consistency of beneficial effects of 25OHD and/or sun exposure for MS risk across multiple racial/ethnic groups. We recruited incident MS cases and controls (blacks 116 cases/131 controls; Hispanics 183/197; whites 247/267 from the membership of Kaiser Permanente Southern California into the MS Sunshine Study to simultaneously examine sun exposure and 25OHD, accounting for genetic ancestry and other factors. Higher lifetime ultraviolet radiation exposure (a rigorous measure of sun exposure was associated with a lower risk of MS independent of serum 25OHD levels in blacks (adjusted OR = 0.53, 95% CI = 0.31–0.83; p = 0.007 and whites (OR = 0.68, 95% CI = 0.48–0.94; p = 0.020 with a similar magnitude of effect that did not reach statistical significance in Hispanics (OR = 0.66, 95% CI = 0.42–1.04; p = 0.071. Higher serum 25OHD levels were associated with a lower risk of MS only in whites. No association was found in Hispanics or blacks regardless of how 25OHD was modeled. Lifetime sun exposure appears to reduce the risk of MS regardless of race/ethnicity. In contrast, serum 25OHD levels are not associated with MS risk in blacks or Hispanics. Our findings challenge the biological plausibility of vitamin D deficiency as causal for MS and call into question the targeting of specific serum 25OHD levels to achieve health benefits, particularly in blacks and Hispanics.

  18. MS Sunshine Study: Sun Exposure But Not Vitamin D Is Associated with Multiple Sclerosis Risk in Blacks and Hispanics.

    Langer-Gould, Annette; Lucas, Robyn; Xiang, Anny H; Chen, Lie H; Wu, Jun; Gonzalez, Edlin; Haraszti, Samantha; Smith, Jessica B; Quach, Hong; Barcellos, Lisa F

    2018-02-27

    Multiple sclerosis (MS) incidence and serum 25-hydroxyvitamin D (25OHD) levels vary by race/ethnicity. We examined the consistency of beneficial effects of 25OHD and/or sun exposure for MS risk across multiple racial/ethnic groups. We recruited incident MS cases and controls (blacks 116 cases/131 controls; Hispanics 183/197; whites 247/267) from the membership of Kaiser Permanente Southern California into the MS Sunshine Study to simultaneously examine sun exposure and 25OHD, accounting for genetic ancestry and other factors. Higher lifetime ultraviolet radiation exposure (a rigorous measure of sun exposure) was associated with a lower risk of MS independent of serum 25OHD levels in blacks (adjusted OR = 0.53, 95% CI = 0.31-0.83; p = 0.007) and whites (OR = 0.68, 95% CI = 0.48-0.94; p = 0.020) with a similar magnitude of effect that did not reach statistical significance in Hispanics (OR = 0.66, 95% CI = 0.42-1.04; p = 0.071). Higher serum 25OHD levels were associated with a lower risk of MS only in whites. No association was found in Hispanics or blacks regardless of how 25OHD was modeled. Lifetime sun exposure appears to reduce the risk of MS regardless of race/ethnicity. In contrast, serum 25OHD levels are not associated with MS risk in blacks or Hispanics. Our findings challenge the biological plausibility of vitamin D deficiency as causal for MS and call into question the targeting of specific serum 25OHD levels to achieve health benefits, particularly in blacks and Hispanics.

  19. Multiple procedures and cumulative individual radiation exposure in interventional cardiology: A long-term retrospective study

    Weltermann, Birgitta M.; Rock, Thomas; Berndt, Peter; Viehmann, Anja; Reinders, Sabrina; Gesenhues, Stefan [University of Duisburg-Essen, Institute for General Medicine, University Hospital, Essen (Germany); Brix, Gunnar; Schegerer, Alexander [Federal Office for Radiation Protection, Department of Radiation Protection and Health, Neuherberg (Germany)

    2015-09-15

    Various studies address discrepancies between guideline recommendations for coronary angiographies and clinical practice. While the issue of the appropriateness of recurrent angiographies was studied focusing on the role of the cardiologist, little is known about individual patients' histories and the associated radiation exposures. We analyzed all patients with coronary artery disease (CAD) in an academic teaching practice who underwent at least one angiography with or without intervention between 2004 and 2009. All performed angiographies in these patients were analyzed and rated by three physicians for appropriateness levels according to cardiology guidelines. Typical exposure data from the medical literature were used to estimate individual radiation exposure. In the cohort of 147 patients, a total of 441 procedures were analyzed: between 1981 and 2009, three procedures were performed per patient (range 1-19) on average. Appropriateness ratings were 'high/intermediate' in 71 %, 'low/no' in 27.6 % and data were insufficient for ratings in 1.4 %. Procedures with 'low/no' ratings were associated with potentially avoidable exposures of up to 186 mSv for single patients. Using retrospective data, we exemplify the potential benefit of guideline adherence to decrease patients' radiation exposures. (orig.)

  20. Chromatic aberration compensation in numerical reconstruction of digital holograms by Fresnel-Bluestein propagation.

    Hincapie, Diego; Velasquez, Daniel; Garcia-Sucerquia, Jorge

    2017-12-15

    In this Letter, we present a method for chromatic compensation in numerical reconstruction of digitally recorded holograms based on Fresnel-Bluestein propagation. The proposed technique is applied to correct the chromatic aberration that arises in the reconstruction of RGB holograms of both millimeter- and micrometer-sized objects. The results show the feasibility of this strategy to remove the wavelength dependence of the size of the numerically propagated wavefields.

  1. Diffraction efficiency of photothermoplastic layers for the recording of discrete holograms

    Koreshev, S. N.; Cherkasov, Yu. A.; Kislovskiy, I. L.

    1987-01-01

    An experimental and theoretical study of the dependence of eta of a digital phase Fourier hologram of a point object on the amount of deformation delta and the discrete-structure parameters representing the hologram is detailed. An expression is given for eta. Experiments were performed on photothermoplastic layers based on polyvinyl carbazole and trinitrofluorenone charge transfer complexes. The maximum eta, 2%, is found at delta = 0.56 micron.

  2. Simulated electronic heterodyne recording and processing of pulsed-laser holograms

    Decker, A. J.

    1979-01-01

    The electronic recording of pulsed-laser holograms is proposed. The polarization sensitivity of each resolution element of the detector is controlled independently to add an arbitrary phase to the image waves. This method which can be used to simulate heterodyne recording and to process three-dimensional optical images, is based on a similar method for heterodyne recording and processing of continuous-wave holograms.

  3. The hologram and its utilization as a physics teaching tool for physics teaching in engineering courses

    Toledo, Rolando Serra; Cruz, Gilda Vega; Zaldo, Angel Ferrat; Lunazzi, José J.; Magalhães, Daniel S.F.

    2009-01-01

    With the emergence and development of the white-light holograms, new possibilities were created for its utilization as a teaching tool due to the characteristic of producing a three-dimensional image which constitutes an optical duplicate of the object. In this work the distinctive aspects of the hologram are described and its utilization is analyzed in engineering courses, through the design and construction of a Didactic Exhibition of Holography. Con el surgimiento de los hologramas reco...

  4. Ultra-sensitive, stable isotope assisted quantification of multiple urinary mycotoxin exposure biomarkers.

    Šarkanj, Bojan; Ezekiel, Chibundu N; Turner, Paul C; Abia, Wilfred A; Rychlik, Michael; Krska, Rudolf; Sulyok, Michael; Warth, Benedikt

    2018-08-17

    There is a critical need to better understand the patterns, levels and combinatory effects of exposures we are facing through our diet and environment. Mycotoxin mixtures are of particular concern due to chronic low dose exposures caused by naturally contaminated food. To facilitate new insights into their role in chronic disease, mycotoxins and their metabolites are quantified in bio-fluids as biomarkers of exposure. Here, we describe a highly sensitive urinary assay based on ultra-high performance liquid chromatography - tandem mass spectrometer (UHPLC-MS/MS) and 13 C-labelled or deuterated internal standards covering the most relevant regulated and emerging mycotoxins. Utilizing enzymatic pre-treatment, solid phase extraction and UHPLC separation, the sensitivity of the method was significantly higher (10-160x lower LODs) than in a previously described method used for comparison purpose, and stable isotopes provided compensation for challenging matrix effects. This method was in-house validated and applied to re-assess mycotoxin exposure in urine samples obtained from Nigerian children, adolescent and adults, naturally exposed through their regular diet. Owing to the methods high sensitivity, biomarkers were detected in all samples. The mycoestrogen zearalenone was the most frequently detected contaminant (82%) but also ochratoxin A (76%), aflatoxin M 1 (73%) and fumonisin B 1 (71%) were quantified in a large share of urines. Overall, 57% of 120 urines were contaminated with both, aflatoxin M 1 and fumonisin B 1 , and other co-exposures were frequent. These results clearly demonstrate the advanced performance of the method to assess lowest background exposures (pg mL -1 range) using a single, highly robust assay that will allow for the systematic investigation of low dose effects on human health. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Integrated Assessment of Shallow-Aquifer Vulnerability to Multiple Contaminants and Drinking-Water Exposure Pathways in Holliston, Massachusetts

    Birgit Claus Henn

    2017-12-01

    Full Text Available Half of U.S. drinking water comes from aquifers, and very shallow ones (<20 feet to water table are especially vulnerable to anthropogenic contamination. We present the case of Holliston, a Boston, Massachusetts suburb that draws its drinking water from very shallow aquifers, and where metals and solvents have been reported in groundwater. Community concerns focus on water discolored by naturally occurring manganese (Mn, despite reports stating regulatory aesthetic compliance. Epidemiologic studies suggest Mn is a potentially toxic element (PTE for children exposed by the drinking-water pathway at levels near the regulatory aesthetic level. We designed an integrated, community-based project: five sites were profiled for contaminant releases; service areas for wells were modeled; and the capture zone for one vulnerable well was estimated. Manganese, mercury, and trichloroethylene are among 20 contaminants of interest. Findings show that past and/or current exposures to multiple contaminants in drinking water are plausible, satisfying the criteria for complete exposure pathways. This case questions the adequacy of aquifer protection and monitoring regulations, and highlights the need for integrated assessment of multiple contaminants, associated exposures and health risks. It posits that community-researcher partnerships are essential for understanding and solving complex problems.

  6. An accelerated hologram calculation using the wavefront recording plane method and wavelet transform

    Arai, Daisuke; Shimobaba, Tomoyoshi; Nishitsuji, Takashi; Kakue, Takashi; Masuda, Nobuyuki; Ito, Tomoyoshi

    2017-06-01

    Fast hologram calculation methods are critical in real-time holography applications such as three-dimensional (3D) displays. We recently proposed a wavelet transform-based hologram calculation called WASABI. Even though WASABI can decrease the calculation time of a hologram from a point cloud, it increases the calculation time with increasing propagation distance. We also proposed a wavefront recoding plane (WRP) method. This is a two-step fast hologram calculation in which the first step calculates the superposition of light waves emitted from a point cloud in a virtual plane, and the second step performs a diffraction calculation from the virtual plane to the hologram plane. A drawback of the WRP method is in the first step when the point cloud has a large number of object points and/or a long distribution in the depth direction. In this paper, we propose a method combining WASABI and the WRP method in which the drawbacks of each can be complementarily solved. Using a consumer CPU, the proposed method succeeded in performing a hologram calculation with 2048 × 2048 pixels from a 3D object with one million points in approximately 0.4 s.

  7. Reconstruction of composite in-line electron holograms using a small emission cone

    Holenstein, Roman; Rothwell, Timothy A.; Shegelski, Mark R.A.

    2003-01-01

    We report a new method that gives atomic resolution in the reconstruction of simulated holograms in theoretical low energy electron point source (LEEPS) microscopy, and that uses a screen size that is commensurate with screen sizes used in experimental LEEPS. The method exploits the spherical symmetry in the electron waves emerging from the source. We compare holograms obtained by rotating the screen about an axis passing through the point source as opposed to rotating the atomic cluster in the opposite sense about the same axis. We show that, by generating and combining simulated holograms obtained by rotating the cluster, with the screen held fixed, a composite hologram, comprised of the individual holograms, captures enough information that atomic resolution in the reconstructions is obtained. A key feature is to choose the rotations to optimize the collective interference pattern on the composite hologram. This results in sharper resolution while using a considerably smaller screen size; results are reported for a screen size about ten times smaller than screen sizes typically used in theoretical LEEPS. The method used gives commensurate or better resolution on comparison to results obtained using the larger screen size. Possible implications for experimental LEEPS are briefly discussed

  8. Fabrication of digital rainbow holograms and 3-D imaging using SEM based e-beam lithography.

    Firsov, An; Firsov, A; Loechel, B; Erko, A; Svintsov, A; Zaitsev, S

    2014-11-17

    Here we present an approach for creating full-color digital rainbow holograms based on mixing three basic colors. Much like in a color TV with three luminescent points per single screen pixel, each color pixel of initial image is presented by three (R, G, B) distinct diffractive gratings in a hologram structure. Change of either duty cycle or area of the gratings are used to provide proper R, G, B intensities. Special algorithms allow one to design rather complicated 3D images (that might even be replacing each other with hologram rotation). The software developed ("RainBow") provides stability of colorization of rotated image by means of equalizing of angular blur from gratings responsible for R, G, B basic colors. The approach based on R, G, B color synthesis allows one to fabricate gray-tone rainbow hologram containing white color what is hardly possible in traditional dot-matrix technology. Budgetary electron beam lithography based on SEM column was used to fabricate practical examples of digital rainbow hologram. The results of fabrication of large rainbow holograms from design to imprinting are presented. Advantages of the EBL in comparison to traditional optical (dot-matrix) technology is considered.

  9. Design, simulation, and optimization of an RGB polarization independent transmission volume hologram

    Mahamat, Adoum Hassan

    Volume phase holographic (VPH) gratings have been designed for use in many areas of science and technology such as optical communication, medical imaging, spectroscopy and astronomy. The goal of this dissertation is to design a volume phase holographic grating that provides diffraction efficiencies of at least 70% for the entire visible wavelengths and higher than 90% for red, green, and blue light when the incident light is unpolarized. First, the complete design, simulation and optimization of the volume hologram are presented. The optimization is done using a Monte Carlo analysis to solve for the index modulation needed to provide higher diffraction efficiencies. The solutions are determined by solving the diffraction efficiency equations determined by Kogelnik's two wave coupled-wave theory. The hologram is further optimized using the rigorous coupled-wave analysis to correct for effects of absorption omitted by Kogelnik's method. Second, the fabrication or recording process of the volume hologram is described in detail. The active region of the volume hologram is created by interference of two coherent beams within the thin film. Third, the experimental set up and measurement of some properties including the diffraction efficiencies of the volume hologram, and the thickness of the active region are conducted. Fourth, the polarimetric response of the volume hologram is investigated. The polarization study is developed to provide insight into the effect of the refractive index modulation onto the polarization state and diffraction efficiency of incident light.

  10. Effects of Multiple Routes of Cadmium Exposure on the Hibernation Success of the American Toad (Bufo americanus)

    James, S.M.; Little, E.E.; Semlitsch, R.D.

    2004-01-01

    The effects of multiple routes of cadmium exposure on juvenile American toads (Bufo americanus) were evaluated using environmentally relevant concentrations. During or after exposure, toads were individually hibernated for 172 days at approximately 4??C. The following experiments were conducted: (1) dermal exposure (hibernation in soil contaminated with up to 120 ??g Cd/ g (dry weight)); (2) injection exposure (single injection with cadmium to achieve a maximum whole-body nominal concentration of 3 ??g Cd/g (wet weight) 12 days before hibernation in uncontaminated soil); and, (3) oral exposure (feeding with mealworms containing ???16 ??g Cd/g (dry weight) for 50 days before hibernation in uncontaminated soil)., We hypothesized that sublethal levels of cadmium would become lethal during hibernation because of combined chemical and cold stress. No prehibernation mortality occurred in the injection and oral exposure studies. There was a significant treatment effect on whole-body cadmium concentration in toads orally or dermally exposed and on percent of cadmium retention in toads orally exposed. There was also a trend of increased time-to-burrowing and more toads partially buried with greater cadmium concentration in the dermal study, which indicated avoidance. In all 3 experiments, no significant differences were found among cadmium treatments in hibernation survival, percent of mass loss, or locomotor performance. However, toads fed mealworms averaging 4.7 ??g Cd/g (dry weight) had only 56% survival compared with 100% survival for controls. Although our results suggest that environmentally relevant levels of cadmium do not pose a great risk to American toads, factors such as soil type or prey species may increase cadmium bioavailability, and other amphibian species may be more sensitive to cadmium than B. americanus.

  11. The effects of exposure to multiple occupational health stressors on distortion product otoacoustic emissions

    Edwards, A

    2012-04-01

    Full Text Available -induced hearing loss (NIHL). Furthermore, exposure to heat is believed to influence the biochemical properties of cochlear outer hair cells (OHCs) and heat stress structurally modifies the OHCs, making them stiffer through an increase in F-actin5. This experiment...

  12. Precision alignment and calibration of optical systems using computer generated holograms

    Coyle, Laura Elizabeth

    As techniques for manufacturing and metrology advance, optical systems are being designed with more complexity than ever before. Given these prescriptions, alignment and calibration can be a limiting factor in their final performance. Computer generated holograms (CGHs) have several unique properties that make them powerful tools for meeting these demanding tolerances. This work will present three novel methods for alignment and calibration of optical systems using computer generated holograms. Alignment methods using CGHs require that the optical wavefront created by the CGH be related to a mechanical datum to locate it space. An overview of existing methods is provided as background, then two new alignment methods are discussed in detail. In the first method, the CGH contact Ball Alignment Tool (CBAT) is used to align a ball or sphere mounted retroreflector (SMR) to a Fresnel zone plate pattern with micron level accuracy. The ball is bonded directly onto the CGH substrate and provides permanent, accurate registration between the optical wavefront and a mechanical reference to locate the CGH in space. A prototype CBAT was built and used to align and bond an SMR to a CGH. In the second method, CGH references are used to align axi-symmetric optics in four degrees of freedom with low uncertainty and real time feedback. The CGHs create simultaneous 3D optical references where the zero order reflection sets tilt and the first diffracted order sets centration. The flexibility of the CGH design can be used to accommodate a wide variety of optical systems and maximize sensitivity to misalignments. A 2-CGH prototype system was aligned multiplied times and the alignment uncertainty was quantified and compared to an error model. Finally, an enhanced calibration method is presented. It uses multiple perturbed measurements of a master sphere to improve the calibration of CGH-based Fizeau interferometers ultimately measuring aspheric test surfaces. The improvement in the

  13. Large-scale neurochemical metabolomics analysis identifies multiple compounds associated with methamphetamine exposure.

    McClay, Joseph L; Adkins, Daniel E; Vunck, Sarah A; Batman, Angela M; Vann, Robert E; Clark, Shaunna L; Beardsley, Patrick M; van den Oord, Edwin J C G

    2013-04-01

    Methamphetamine (MA) is an illegal stimulant drug of abuse with serious negative health consequences. The neurochemical effects of MA have been partially characterized, with a traditional focus on classical neurotransmitter systems. However, these directions have not yet led to novel drug treatments for MA abuse or toxicity. As an alternative approach, we describe here the first application of metabolomics to investigate the neurochemical consequences of MA exposure in the rodent brain. We examined single exposures at 3 mg/kg and repeated exposures at 3 mg/kg over 5 days in eight common inbred mouse strains. Brain tissue samples were assayed using high-throughput gas and liquid chromatography mass spectrometry, yielding quantitative data on >300 unique metabolites. Association testing and false discovery rate control yielded several metabolome-wide significant associations with acute MA exposure, including compounds such as lactate ( p = 4.4 × 10 -5 , q = 0.013), tryptophan ( p = 7.0 × 10 -4 , q = 0.035) and 2-hydroxyglutarate ( p = 1.1 × 10 -4 , q = 0.022). Secondary analyses of MA-induced increase in locomotor activity showed associations with energy metabolites such as succinate ( p = 3.8 × 10 -7 ). Associations specific to repeated (5 day) MA exposure included phosphocholine ( p = 4.0 × 10 -4 , q = 0.087) and ergothioneine ( p = 3.0 × 10 -4 , q = 0.087). Our data appear to confirm and extend existing models of MA action in the brain, whereby an initial increase in energy metabolism, coupled with an increase in behavioral locomotion, gives way to disruption of mitochondria and phospholipid pathways and increased endogenous antioxidant response. Our study demonstrates the power of comprehensive MS-based metabolomics to identify drug-induced changes to brain metabolism and to develop neurochemical models of drug effects.

  14. Cytogenetic bio-dosimetry of an accidental exposure of a radiological worker using multiple assays

    Thierens, H.; De Ruyck, K.; Vral, A.; De Gelder, V.; Whitehouse, C. A.; Tawn, E. J.; Boesman, I.

    2005-01-01

    A technician involved in the maintenance of X-ray equipment visited the occupational medicine service with complaints of skin lesions, apparently caused by an accidental exposure three months earlier. To estimate the dose received by the technician in the accident, bio-dosimetry was performed 6 and 18 months post-exposure with the dicentric and micronucleus assays. Part of the latest blood sample was also used for retrospective dosimetry by fluorescence in situ hybridisation (FISH) analysis for translocations. The data obtained 6 and 18 months post-exposure indicate that both dicentrics and micronuclei disappear with a half-time of 1 y. After correction for delayed blood sampling, dose values of 0.75 Gy (95% confidence limits 0.56-1.05 Gy) from dicentrics and 0.96 Gy (95% confidence limits 0.79-1.18 Gy) from micronuclei were obtained. FISH analysis of translocations resulted in a dose estimate of 0.79 Gy (95% confidence limits 0.61-0.99 Gy). The satisfactory agreement between the three cytogenetic endpoints supports the use of the micronucleus assay for triage purposes in the case of large scale radiological accidents and provides further evidence for the valid use of FISH for translocations as a reliable retrospective biological dosimeter. (authors)

  15. Four exposure holography system

    Mix, L.P.; Kessler, R.W.

    1977-03-01

    A four exposure holographic interferometry system, designed for studying transient phenomena occurring on nanosecond time scales and particularly those associated with relativistic electron beams, is described. This system permits four holographic exposures of a single transient event to be made with independently adjustable interpulse spacings of from 6 to 28 nsec. The system is portable, allows for a wide range of image magnifications, features colinear scene beams to facilitate alignment and large aperture imaging lenses to minimize refraction phenomena. The various design parameters are discussed and typical holograms presented to indicate the types of data which may be obtained

  16. Comparative chlorpyrifos pharmacokinetics via multiple routes of exposure and vehicles of administration in the adult rat

    Smith, Jordan Ned; Campbell, James A.; Busby-Hjerpe, Andrea L.; Lee, Sookwang; Poet, Torka S.; Barr, Dana B.; Timchalk, Charles

    2009-01-01

    Chlorpyrifos (CPF) is a commonly used organophosphorus pesticide. A number of toxicity and mechanistic studies have been conducted in animals, where CPF has been administered via a variety of different exposure routes and dosing vehicles. This study compared chlorpyrifos (CPF) pharmacokinetics using oral, intravenous (IV), and subcutaneous (SC) exposure routes and corn oil, saline/Tween 20, and dimethyl sulfoxide (DMSO) as dosing vehicles. Two groups of rats were co-administered target doses (5 mg/kg) of CPF and isotopically labeled CPF (L-CPF). One group was exposed by both oral (CPF) and IV (L-CPF) routes using saline/Tween 20 vehicle; whereas, the second group was exposed by the SC route using two vehicles, corn oil (CPF) and DMSO (L-CPF). A third group was only administered CPF by the oral route in corn oil. For all treatments, blood and urine time course samples were collected and analyzed for 3,5,6-trichloro-2-pyridinol (TCPy), and isotopically labeled 3,5,6-trichloro-2-pyridinol (L-TCPy). Peak TCPy/L-TCPy concentrations in blood (20.2 μmol/l), TCPy/L-TCPy blood AUC (94.9 μmol/l h), and percent of dose excreted in urine (100%) were all highest in rats dosed orally with CPF in saline/Tween 20 and second highest in rats dosed orally with CPF in corn oil. Peak TCPy concentrations in blood were more rapidly obtained after oral administration of CPF in saline/Tween 20 compared to all other dosing scenarios (>1.5 h). These results indicate that orally administered CPF is more extensively metabolized than systemic exposures of CPF (SC and IV), and vehicle of administration also has an effect on absorption rates. Thus, equivalent doses via different routes and/or vehicles of administration could potentially lead to different body burdens of CPF, different rates of bioactivation to CPF-oxon, and different toxic responses. Simulations using a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model for CPF are consistent with these possibilities

  17. Multiple routes of pesticide exposure for honey bees living near agricultural fields.

    Christian H Krupke

    Full Text Available Populations of honey bees and other pollinators have declined worldwide in recent years. A variety of stressors have been implicated as potential causes, including agricultural pesticides. Neonicotinoid insecticides, which are widely used and highly toxic to honey bees, have been found in previous analyses of honey bee pollen and comb material. However, the routes of exposure have remained largely undefined. We used LC/MS-MS to analyze samples of honey bees, pollen stored in the hive and several potential exposure routes associated with plantings of neonicotinoid treated maize. Our results demonstrate that bees are exposed to these compounds and several other agricultural pesticides in several ways throughout the foraging period. During spring, extremely high levels of clothianidin and thiamethoxam were found in planter exhaust material produced during the planting of treated maize seed. We also found neonicotinoids in the soil of each field we sampled, including unplanted fields. Plants visited by foraging bees (dandelions growing near these fields were found to contain neonicotinoids as well. This indicates deposition of neonicotinoids on the flowers, uptake by the root system, or both. Dead bees collected near hive entrances during the spring sampling period were found to contain clothianidin as well, although whether exposure was oral (consuming pollen or by contact (soil/planter dust is unclear. We also detected the insecticide clothianidin in pollen collected by bees and stored in the hive. When maize plants in our field reached anthesis, maize pollen from treated seed was found to contain clothianidin and other pesticides; and honey bees in our study readily collected maize pollen. These findings clarify some of the mechanisms by which honey bees may be exposed to agricultural pesticides throughout the growing season. These results have implications for a wide range of large-scale annual cropping systems that utilize neonicotinoid seed

  18. Increasing the understanding of chemical concepts: The effectiveness of multiple exposures

    Bius, Janet H.

    Chemistry is difficult because it has multilevels of knowledge with each level presenting challenges in vocabulary, abstract thinking, and symbolic language. Students have to be able to transfer between levels to understand the concepts and the theoretical models of chemistry. The cognitive theories of constructivism and cognitive-load theory are used to explain the difficulties novice learners have with the subject of chemistry and methods to increase success for students. The relationship between external representations, misconceptions and topics on the success of students are addressed. If students do not know the formalisms associated with chemical diagrams and graphs, the representations will decrease student success. Misconceptions can be formed when new information is interpreted based on pre-existing knowledge that is faulty. Topics with large amount of interacting elements that must be processed simultaneously are considered difficult to understand. New variables were created to measure the number of times a student is exposed to a chemical concept. Each variable was coded according to topic and learning environment, which are the lecture and laboratory components of the course, homework assignments and textbook examples. The exposure variables are used to measure the success rate of students on similar exam questions. Question difficulty scales were adapted for this project from those found in the chemical education literature. The exposure variables were tested on each level of the difficulty scales to determine their effect at decreasing the cognitive demand of these questions. The subjects of this study were freshmen science majors at a large Midwest university. The effects of the difficulty scales and exposure variables were measured for those students whose exam scores were in the upper one-fourth percentile, for students whose test scores were in the middle one-half percentile, and the lower one-fourth percentile are those students that scored the

  19. Multiple metals exposure in a small-scale artisanal gold mining community.

    Basu, Niladri; Nam, Dong-Ha; Kwansaa-Ansah, Edward; Renne, Elisha P; Nriagu, Jerome O

    2011-04-01

    Urinary metals were characterized in 57 male residents of a small-scale gold mining community in Ghana. Chromium and arsenic exceeded health guideline values for 52% and 34%, respectively, of all participants. About 10-40% of the participants had urinary levels of aluminum, copper, manganese, nickel, selenium, and zinc that fell outside the U.S. reference range. Exposures appear ubiquitous across the community as none of the elements were associated with occupation, age, and diet. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Assessing exposure to violence using multiple informants: application of hierarchical linear model.

    Kuo, M; Mohler, B; Raudenbush, S L; Earls, F J

    2000-11-01

    The present study assesses the effects of demographic risk factors on children's exposure to violence (ETV) and how these effects vary by informants. Data on exposure to violence of 9-, 12-, and 15-year-olds were collected from both child participants (N = 1880) and parents (N = 1776), as part of the assessment of the Project on Human Development in Chicago Neighborhoods (PHDCN). A two-level hierarchical linear model (HLM) with multivariate outcomes was employed to analyze information obtained from these two different groups of informants. The findings indicate that parents generally report less ETV than do their children and that associations of age, gender, and parent education with ETV are stronger in the self-reports than in the parent reports. The findings support a multivariate approach when information obtained from different sources is being integrated. The application of HLM allows an assessment of interactions between risk factors and informants and uses all available data, including data from one informant when data from the other informant is missing.

  1. Computer Generated Hologram System for Wavefront Measurement System Calibration

    Olczak, Gene

    2011-01-01

    Computer Generated Holograms (CGHs) have been used for some time to calibrate interferometers that require nulling optics. A typical scenario is the testing of aspheric surfaces with an interferometer placed near the paraxial center of curvature. Existing CGH technology suffers from a reduced capacity to calibrate middle and high spatial frequencies. The root cause of this shortcoming is as follows: the CGH is not placed at an image conjugate of the asphere due to limitations imposed by the geometry of the test and the allowable size of the CGH. This innovation provides a calibration system where the imaging properties in calibration can be made comparable to the test configuration. Thus, if the test is designed to have good imaging properties, then middle and high spatial frequency errors in the test system can be well calibrated. The improved imaging properties are provided by a rudimentary auxiliary optic as part of the calibration system. The auxiliary optic is simple to characterize and align to the CGH. Use of the auxiliary optic also reduces the size of the CGH required for calibration and the density of the lines required for the CGH. The resulting CGH is less expensive than the existing technology and has reduced write error and alignment error sensitivities. This CGH system is suitable for any kind of calibration using an interferometer when high spatial resolution is required. It is especially well suited for tests that include segmented optical components or large apertures.

  2. Mobile glasses-free 3D using compact waveguide hologram

    Pyun, K.; Choi, C.; Morozov, A.; Putilin, A.; Bovsunovskiy, I.; Kim, S.; Ahn, J.; Lee, H.-S.; Lee, S.

    2013-02-01

    The exploding mobile communication devices make 3D data available anywhere anytime. However, to record and reconstruct 3D, the huge number of optical components is often required, which makes overall device size bulky and image quality degraded due to the error-prone tuning. In addition, if additional glass is required, then user experience of 3D is exhausting and unpleasant. Holography is the ultimate 3D that users experience natural 3D in every direction. For mobile glasses-free 3D experience, it is critical to make holography device that can be as compact and integrated as possible. For reliable and economical mass production, integrated optics is needed as integrated circuits in semiconductor industry. Thus, we propose mobile glasses-free 3D using compact waveguide hologram in terms of overall device sizes, quantity of elements and combined functionality of each element. The main advantages of proposed solution are as follows: First, this solution utilizes various integral optical elements, where each of them is a united not adjustable optical element, replacing separate and adjustable optical elements with various forms and configurations. Second, geometrical form of integral elements provides small sizes of whole device. Third, geometrical form of integral elements allows creating flat device. And finally, absence of adjustable elements provide rigidly of whole device. The usage of integrated optical means based on waveguide holographic elements allows creating a new type of compact and high functional devices for mobile glasses-free 3D applications such as mobile medical 3D data visualization.

  3. Mobile glasses-free 3D using compact waveguide hologram

    Pyun, K; Choi, C; Kim, S; Ahn, J; Lee, H-S; Lee, S; Morozov, A; Bovsunovskiy, I; Putilin, A

    2013-01-01

    The exploding mobile communication devices make 3D data available anywhere anytime. However, to record and reconstruct 3D, the huge number of optical components is often required, which makes overall device size bulky and image quality degraded due to the error-prone tuning. In addition, if additional glass is required, then user experience of 3D is exhausting and unpleasant. Holography is the ultimate 3D that users experience natural 3D in every direction. For mobile glasses-free 3D experience, it is critical to make holography device that can be as compact and integrated as possible. For reliable and economical mass production, integrated optics is needed as integrated circuits in semiconductor industry. Thus, we propose mobile glasses-free 3D using compact waveguide hologram in terms of overall device sizes, quantity of elements and combined functionality of each element. The main advantages of proposed solution are as follows: First, this solution utilizes various integral optical elements, where each of them is a united not adjustable optical element, replacing separate and adjustable optical elements with various forms and configurations. Second, geometrical form of integral elements provides small sizes of whole device. Third, geometrical form of integral elements allows creating flat device. And finally, absence of adjustable elements provide rigidly of whole device. The usage of integrated optical means based on waveguide holographic elements allows creating a new type of compact and high functional devices for mobile glasses-free 3D applications such as mobile medical 3D data visualization.

  4. Hologram QSAR model for the prediction of human oral bioavailability.

    Moda, Tiago L; Montanari, Carlos A; Andricopulo, Adriano D

    2007-12-15

    A drug intended for use in humans should have an ideal balance of pharmacokinetics and safety, as well as potency and selectivity. Unfavorable pharmacokinetics can negatively affect the clinical development of many otherwise promising drug candidates. A variety of in silico ADME (absorption, distribution, metabolism, and excretion) models are receiving increased attention due to a better appreciation that pharmacokinetic properties should be considered in early phases of the drug discovery process. Human oral bioavailability is an important pharmacokinetic property, which is directly related to the amount of drug available in the systemic circulation to exert pharmacological and therapeutic effects. In the present work, hologram quantitative structure-activity relationships (HQSAR) were performed on a training set of 250 structurally diverse molecules with known human oral bioavailability. The most significant HQSAR model (q(2)=0.70, r(2)=0.93) was obtained using atoms, bond, connection, and chirality as fragment distinction. The predictive ability of the model was evaluated by an external test set containing 52 molecules not included in the training set, and the predicted values were in good agreement with the experimental values. The HQSAR model should be useful for the design of new drug candidates having increased bioavailability as well as in the process of chemical library design, virtual screening, and high-throughput screening.

  5. The development of a methodology to assess population doses from multiple sources and exposure pathways of radioactivity

    Hancox, J.; Stansby, S.; Thorne, M.

    2002-01-01

    The Environment Agency (EA) has new duties in accordance with the Basic Safety Standards Directive under which it is required to ensure that doses to individuals received from exposure to anthropogenic sources of radioactivity are within defined limits. In order to assess compliance with these requirements, the EA needs to assess the doses to members of the most highly exposed population groups ('critical' groups) from all relevant potential sources of anthropogenic radioactivity and all relevant potential exposure pathways to such radioactivity. The EA has identified a need to develop a methodology for the retrospective assessment of effective doses from multiple sources of radioactive materials and exposure pathways associated with those sources. Under contract to the EA, AEA Technology has undertaken the development of a suitable methodology as part of EA R and D Project P3-070. The methodology developed under this research project has been designed to support the EA in meeting its obligations under the Euratom Basic Safety Standards Directive and is consistent with UK and international approaches to radiation dosimetry and radiological protection. The development and trial application of the methodology is described in this report

  6. Exposure to Multiple Pesticides and Risk of Non-Hodgkin Lymphoma in Men from Six Canadian Provinces

    Hohenadel, Karin; Harris, Shelley A.; McLaughlin, John R.; Spinelli, John J.; Pahwa, Punam; Dosman, James A.; Demers, Paul A.; Blair, Aaron

    2011-01-01

    Non-Hodgkin lymphoma (NHL) has been linked to several agricultural exposures, including some commonly used pesticides. Although there is a significant body of literature examining the effects of exposure to individual pesticides on NHL, the impact of exposure to multiple pesticides or specific pesticide combinations has not been explored in depth. Data from a six-province Canadian case-control study conducted between 1991 and 1994 were analyzed to investigate the relationship between NHL, the total number of pesticides used and some common pesticide combinations. Cases (n = 513) were identified through hospital records and provincial cancer registries and controls (n = 1,506), frequency matched to cases by age and province of residence, were obtained through provincial health records, telephone listings, or voter lists. In multiple logistic regression analyses, risk of NHL increased with the number of pesticides used. Similar results were obtained in analyses restricted to herbicides, insecticides and several pesticide classes. Odds ratios increased further when only ‘potentially carcinogenic’ pesticides were considered (OR[one pesticide] = 1.30, 95% CI = 0.90–1.88; OR[two to four] = 1.54, CI = 1.11–2.12; OR[five or more] = 1.94, CI = 1.17–3.23). Elevated risks were also found among those reporting use of malathion in combination with several other pesticides. These analyses support and extend previous findings that the risk of NHL increases with the number of pesticides used and some pesticide combinations. PMID:21776232

  7. Robust image registration for multiple exposure high dynamic range image synthesis

    Yao, Susu

    2011-03-01

    Image registration is an important preprocessing technique in high dynamic range (HDR) image synthesis. This paper proposed a robust image registration method for aligning a group of low dynamic range images (LDR) that are captured with different exposure times. Illumination change and photometric distortion between two images would result in inaccurate registration. We propose to transform intensity image data into phase congruency to eliminate the effect of the changes in image brightness and use phase cross correlation in the Fourier transform domain to perform image registration. Considering the presence of non-overlapped regions due to photometric distortion, evolutionary programming is applied to search for the accurate translation parameters so that the accuracy of registration is able to be achieved at a hundredth of a pixel level. The proposed algorithm works well for under and over-exposed image registration. It has been applied to align LDR images for synthesizing high quality HDR images..

  8. Toxicopathology and immunotoxicology of multiple exposures to diesel and crude oils in cattle

    Dziwenka, M.M.; Coppock, R.W.; Khan, A.A.; Hiltz, M.N.; Nation, P.N.; Field, C.J.

    2002-01-01

    The subchronic toxicology of crude and refined petroleum in cattle was examined during the course of a large study in which 40 cattle were gavaged with potable water, winter diesel fuel and crude oil for a period of up to 48 days. Blood samples for clinicopathologic parameters were collected weekly. The cattle were necropsied 22 days following the last dose. Representative tissues were taken from all organ systems for histopathology. It was shown that repeated oral exposure to petroleum products resulted in significant changes in the clinicopathologic and immunopathologic parameters of the cattle without producing significant macro- or microscopic tissue lesions. The liver was a target organ for subchronic crude and diesel toxicity. 5 refs., 1 tab., 10 figs

  9. On-road PM2.5 pollution exposure in multiple transport microenvironments in Delhi

    Goel, Rahul; Gani, Shahzad; Guttikunda, Sarath K.; Wilson, Daniel; Tiwari, Geetam

    2015-12-01

    PM2.5 pollution in Delhi averaged 150 μg/m3 from 2012 through 2014, which is 15 times higher than the World Health Organization's annual-average guideline. For this setting, we present on-road exposure of PM2.5 concentrations for 11 transport microenvironments along a fixed 8.3-km arterial route, during morning rush hour. The data collection was carried out using a portable TSI DustTrak DRX 8433 aerosol monitor, between January and May (2014). The monthly-average measured ambient concentrations varied from 130 μg/m3 to 250 μg/m3. The on-road PM2.5 concentrations exceeded the ambient measurements by an average of 40% for walking, 10% for cycle, 30% for motorised two wheeler (2W), 30% for open-windowed (OW) car, 30% for auto rickshaw, 20% for air-conditioned as well as for OW bus, 20% for bus stop, and 30% for underground metro station. On the other hand, concentrations were lower by 50% inside air-conditioned (AC) car and 20% inside the metro rail carriage. We find that the percent exceedance for open modes (cycle, auto rickshaw, 2W, OW car, and OW bus) reduces non-linearly with increasing ambient concentration. The reduction is steeper at concentrations lower than 150 μg/m3 than at higher concentrations. After accounting for air inhalation rate and speed of travel, PM2.5 mass uptake per kilometer during cycling is 9 times of AC car, the mode with the lowest exposure. At current level of concentrations, an hour of cycling in Delhi during morning rush-hour period results in PM2.5 dose which is 40% higher than an entire-day dose in cities like Tokyo, London, and New York, where ambient concentrations range from 10 to 20 μg/m3.

  10. Perinatal multiple exposure to neurotoxic (lead, methylmercury, ethylmercury, and aluminum) substances and neurodevelopment at six and 24 months of age

    Marques, Rejane C.; Bernardi, José V.E.; Dórea, José G.; Moreira de Fatima R, Maria; Malm, Olaf

    2014-01-01

    We studied neurodevelopment in infants from two communities. Children living in the vicinity of tin-ore kilns and smelters – TOKS; n = 51) were compared to children from a fishing village (Itapuã; n = 45). Mean hair-Hg (HHg) concentrations were significantly higher in Itapuã children which received significantly (p = 0.0000001) less mean ethylmercury (88.6 μg) from Thimerosal-containing vaccines (TCV) than the TOKS children (120 μg). Breast-milk Pb concentrations were significantly higher in the TOKS mothers (p = 0.000017; 10.04 vs. 3.9 μg L −1 ). Bayley mental development index (MDI) and psychomotor development index (PDI) were statistically significant (respectively p < 0.0000001, p = 0.000007) lower for the TOKS children only at 24 months of age. Multivariate regression analysis showed that MDI was negatively affected by breast-milk Pb and by HHg. PDI was positively affected by breastfeeding and negatively affected by ethylmercury. Milestone achievements were negatively affected by breast-milk Pb (age of walking) and by HHg (age of talking). - Highlights: • Maternal MeHg and Pb, and iatrogenic EtHg (plus Al) exposures are real life scenarios. • Multiple exposures in early life are a dominant cause of neurodevelopmental delays. • Aggravation and/or reversibility of outcomes followed identifiable exposure patterns. - Distinct patterns of metal exposures showed significant differences in neurodevelopmental outcomes. Pb and EtHg showed a dominant cause of neurodevelopmental delays

  11. Challenges in using GPUs for the reconstruction of digital hologram images

    Reid, I D; Nebrensky, J J; Hobson, P R

    2012-01-01

    In-line holographic imaging is used for small particulates, such as cloud or spray droplets, marine plankton, and alluvial sediments, and enables a true 3D object field to be recorded at high resolution over a considerable depth. To reconstruct a digital hologram a 2D FFT must be calculated for every depth slice desired in the replayed image volume. A typical in-line hologram of ∼ 100 micrometre-sized particles over a depth of a few hundred millimetres will require O(1000) 2D FFT operations to be performed on an hologram of typically a few million pixels. In previous work we have reported on our experiences with reconstruction on a computational grid. In this paper we discuss the technical challenges in making efficient use of the NVIDIA Tesla and Fermi GPU systems and show how our reconstruction code was optimised for near real-time video slice reconstruction with holograms as large as 4K by 4K pixels. We also consider the implications for grid and cloud computing approaches to hologram replay, and the extent to which a GPU can replace these approaches, when the important step of locating focussed objects within a reconstructed volume is included.

  12. Polarization-independent broadband meta-holograms via polarization-dependent nanoholes.

    Zhang, Xiaohu; Li, Xiong; Jin, Jinjin; Pu, Mingbo; Ma, Xiaoliang; Luo, Jun; Guo, Yinghui; Wang, Changtao; Luo, Xiangang

    2018-05-17

    Composed of ultrathin metal or dielectric nanostructures, metasurfaces can manipulate the phase, amplitude and polarization of electromagnetic waves at a subwavelength scale, which is promising for flat optical devices. In general, metasurfaces composed of space-variant anisotropic units are sensitive to the incident polarization due to the inherent polarization dependent geometric phase. Here, we implement polarization-independent broadband metasurface holograms constructed by polarization-dependent anisotropic elliptical nanoholes by elaborate design of complex amplitude holograms. The fabricated meta-hologram exhibits a polarization insensitive feature with an acceptable image quality. We verify the feasibility of the design algorithm for three-dimensional (3D) meta-holograms with simulation and the feasibility for two-dimensional (2D) meta-holograms is experimentally demonstrated at a broadband wavelength range from 405 nm to 632.8 nm. The effective polarization-independent broadband complex wavefront control with anisotropic elliptical nanoholes proposed in this paper greatly promotes the practical applications of the metasurface in technologies associated with wavefront manipulation, such as flat lens, colorful holographic displays and optical storage.

  13. Circularly-polarized, semitransparent and double-sided holograms based on helical photonic structures.

    Kobashi, Junji; Yoshida, Hiroyuki; Ozaki, Masanori

    2017-11-28

    Recent advances in nanofabrication techniques are opening new frontiers in holographic devices, with the capability to integrate various optical functions in a single device. However, while most efficient holograms are achieved in reflection-mode configurations, they are in general opaque because of the reflective substrate that must be used, and therefore, have limited applicability. Here, we present a semi-transparent, reflective computer-generated hologram that is circularly-polarization dependent, and reconstructs different wavefronts when viewed from different sides. The integrated functionality is realized using a single thin-film of liquid crystal with a self-organized helical structure that Bragg reflects circularly-polarized light over a certain band of wavelengths. Asymmetry depending on the viewing side is achieved by exploiting the limited penetration depth of light in the helical structure as well as the nature of liquid crystals to conform to different orientational patterns imprinted on the two substrates sandwiching the material. Also, because the operation wavelength is determined by the reflection band position, pseudo-color holograms can be made by simply stacking layers with different designs. The unique characteristics of this hologram may find applications in polarization-encoded security holograms and see-through holographic signage where different information need to be displayed depending on the viewing direction.

  14. Fast precalculated triangular mesh algorithm for 3D binary computer-generated holograms.

    Yang, Fan; Kaczorowski, Andrzej; Wilkinson, Tim D

    2014-12-10

    A new method for constructing computer-generated holograms using a precalculated triangular mesh is presented. The speed of calculation can be increased dramatically by exploiting both the precalculated base triangle and GPU parallel computing. Unlike algorithms using point-based sources, this method can reconstruct a more vivid 3D object instead of a "hollow image." In addition, there is no need to do a fast Fourier transform for each 3D element every time. A ferroelectric liquid crystal spatial light modulator is used to display the binary hologram within our experiment and the hologram of a base right triangle is produced by utilizing just a one-step Fourier transform in the 2D case, which can be expanded to the 3D case by multiplying by a suitable Fresnel phase plane. All 3D holograms generated in this paper are based on Fresnel propagation; thus, the Fresnel plane is treated as a vital element in producing the hologram. A GeForce GTX 770 graphics card with 2 GB memory is used to achieve parallel computing.

  15. Three-dimensional atomic-image reconstruction from a single-energy Si(100) photoelectron hologram

    Matsushita, T.; Agui, A.; Yoshigoe, A.

    2004-01-01

    Full text: J. J. Barton proposed a basic algorithm for three-dimensional atomic-image reconstruction from photoelectron hologram, which is based on the Fourier transform(FT). In the use of a single-energy hologram, the twin-image appears in principle. The twin image disappears in the use of multi-energy hologram, which requires longer measuring time and variable-energy light source. But the reconstruction in the use of a simple FT is difficult because the scattered electron wave is not s-symmetric wave. Many theoretical and experimental approaches based on the FT have been researched. We propose a new algorithm so-called 'scattering pattern matrix', which is not based on the FT. The algorithm utilizes the 'scattering pattern', and iterative gradient method. Real space image can be reconstructed from a single-energy hologram without initial model. In addition, the twin image disappears. We reconstructed the three-dimensional atomic image of Si bulk structure from an experimental single-energy hologram of Si(100) 2s emission, which is shown The experiment was performed with using a Al-K α light source. The experimental setup is shown in. Then we calculated a vertical slice image of the reconstructed Si bulk structure, which is shown. The atomic images appear around the expected positions

  16. Single beam write and/or replay of spatial heterodyne holograms

    Thomas, Clarence E.; Hanson, Gregory R.

    2007-11-20

    A method of writing a spatially heterodyne hologram having spatially heterodyne fringes includes: passing a single write beam through a spatial light modulator that digitally modulates said single write beam; and focusing the single write beam at a focal plane of a lens to impose a holographic diffraction grating pattern on the photorefractive crystal, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein only said single write beam is incident on said photorefractive crystal without a reference beam. A method of replaying a spatially heterodyne hologram having spatially heterodyne fringes at a replay angle includes: illuminating a photorefractive crystal having a holographic diffraction grating with a beam from a laser at an illumination angle, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein a difference between said illumination angle and said replay angle defines a diffraction angle .alpha. that is a function of a plane wave mathematically added to original object wave phase and amplitude data of said spatially heterodyne hologram having spatially heterodyne fringes.

  17. An Evaluation Of Holograms In Training And As Job Performance Aids

    Frey, Allan H.

    1986-08-01

    Experimentation was carried out to evaluate holograms for use in training and as job aids. Holograms were compared against line drawings and photographs as methods of presenting visual information needed to accomplish a number of tasks. The dependent variables were assembly speed and assembly errors with people unstressed, assembly speed and assembly errors with people stressed, the percentage of discovered errors in assemblies, the number of correct assemblies misidentified as erroneous, and information extraction. Holograms generally were as good as or better visual aids than either photographs or line drawings. The use of holograms tends to reduce errors rather than speed assembly time in the assembly tasks used in these experiments. They also enhance the discovery of errors when the subject is attempting to locate assembly errors in a construction. The results of this experimentation suggest that serious consideration should be given to the use of holography in the development of job aids and in training. Besides these advantages for job aids, other advantages we found are that when page formated information is stored in man-readable holograms they are still useable when scratched or damaged even when similarly damaged microfilm is unuseable. Holography can also be used to store man and machine readable data simultaneously. Such storage would provide simplified backup in the event of machine failure, and it would permit the development of compatible machine and manual systems for job aid applications.

  18. The pharmacokinetic properties of bifenthrin in the rat following multiple routes of exposure.

    Gammon, Derek; Liu, Zhiwei; Chandrasekaran, Appavu; ElNaggar, Shaaban

    2015-06-01

    Pyrethroids generally have relatively low oral toxicity but variable inhalation toxicity. The pharmacokinetics of bifenthrin in the rat after oral, inhalation and intravenous administration is described. Pyrethroid acute toxicity via oral and inhalation routes is also presented. Groups of male rats were dosed by oral gavage at 3.1 mg kg(-1) in 1 mL kg(-1) of corn oil (the critical, acute, oral benchmark dose lower limit, BMDL) and at an equivalent dose by inhalation (0.018 mg L(-1)) for 4 h.  At 2, 4, 6, 8 and 12 h after dosing initiation, blood plasma and brain bifenthrin concentrations were measured. The maximum concentrations of bifenthrin in plasma were 361 ng mL(-1) or 0.853 μM (oral) and 232 ng mL(-1) or 0.548 μM (inhalation), and in brain they were 83 and 73 ng g(-1). The area under the concentration versus time curve (AUC) values were 1969 h ng mL(-1) (plasma) and 763 h ng mL(-1) (brain) following oral gavage dosing, and 1584 h ng mL(-1) (plasma) and 619 h ng mL(-1) (brain) after inhalation. Intravenous dosing resulted in apparent terminal half-life (t1/2 ) values of 13.4 h (plasma) and 11.1 h (brain) and in AUC0-∞ values of 454 and 1566 h ng mL(-1) for plasma and brain. Clearance from plasma was 37 mL min(-1) kg(-1). Peak plasma nd brain concentrations were generally a little higher after oral dosing (by ca 14%). Inhalation administration of bifenthrin did not cause increases in exposure in plasma or brain by avoiding first-pass effects in the liver. The elimination t1/2 was comparable with other pyrethroids and indicated little bioaccumulation potential. These pharmokinetics data allow risks following inhalation exposure to be modeled using oral toxicity data. © 2014 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  19. Numerically correcting the joint misplacement of the sub-holograms in spatial synthetic aperture digital Fresnel holography.

    Jiang, Hongzhen; Zhao, Jianlin; Di, Jianglei; Qin, Chuan

    2009-10-12

    We propose an effective reconstruction method for correcting the joint misplacement of the sub-holograms caused by the displacement error of CCD in spatial synthetic aperture digital Fresnel holography. For every two adjacent sub-holograms along the motion path of CCD, we reconstruct the corresponding holographic images under different joint distances between the sub-holograms and then find out the accurate joint distance by evaluating the quality of the corresponding synthetic reconstructed images. Then the accurate relative position relationships of the sub-holograms can be confirmed according to all of the identified joint distances, with which the accurate synthetic reconstructed image can be obtained by superposing the reconstruction results of the sub-holograms. The numerical reconstruction results are in agreement with the theoretical analysis. Compared with the traditional reconstruction method, this method could be used to not only correct the joint misplacement of the sub-holograms without the limitation of the actually overlapping circumstances of the adjacent sub-holograms, but also make the joint precision of the sub-holograms reach sub-pixel accuracy.

  20. Projection multiplex recording of computer-synthesised one-dimensional Fourier holograms for holographic memory systems: mathematical and experimental modelling

    Betin, A Yu; Bobrinev, V I; Verenikina, N M; Donchenko, S S; Odinokov, S B [Research Institute ' Radiotronics and Laser Engineering' , Bauman Moscow State Technical University, Moscow (Russian Federation); Evtikhiev, N N; Zlokazov, E Yu; Starikov, S N; Starikov, R S [National Reseach Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation)

    2015-08-31

    A multiplex method of recording computer-synthesised one-dimensional Fourier holograms intended for holographic memory devices is proposed. The method potentially allows increasing the recording density in the previously proposed holographic memory system based on the computer synthesis and projection recording of data page holograms. (holographic memory)

  1. Computer-assisted time-averaged holograms of the motion of the surface of the mammalian tympanic membrane with sound stimuli of 0.4 to 25 kHz

    Rosowski, John J.; Cheng, Jeffrey Tao; Ravicz, Michael E.; Hulli, Nesim; Hernandez-Montes, Maria; Harrington, Ellery; Furlong, Cosme

    2009-01-01

    Time-averaged holograms describing the sound-induced motion of the tympanic membrane (TM) in cadaveric preparations from three mammalian species and one live ear were measured using opto-electronic holography. This technique allows rapid measurements of the magnitude of motion of the tympanic membrane surface at frequencies as high as 25 kHz. The holograms measured in response to low and middle-frequency sound stimuli are similar to previously reported time-averaged holograms. However, at higher frequencies (f > 4 kHz), our holograms reveal unique TM surface displacement patterns that consist of highly-ordered arrangements of multiple local displacement magnitude maxima, each of which is surrounded by nodal areas of low displacement magnitude. These patterns are similar to modal patterns (two-dimensional standing waves) produced by either the interaction of surface waves traveling in multiple directions or the uniform stimulation of modes of motion that are determined by the structural properties and boundary conditions of the TM. From the ratio of the displacement magnitude peaks to nodal valleys in these apparent surface waves, we estimate a Standing Wave Ratio of at least 4 that is consistent with energy reflection coefficients at the TM boundaries of at least 0.35. It is also consistent with small losses within the uniformly stimulated modal surface waves. We also estimate possible TM surface wave speeds that vary with frequency and species from 20 to 65 m/s, consistent with other estimates in the literature. The presence of standing wave or modal phenomena has previously been intuited from measurements of TM function, but is ignored in some models of tympanic membrane function. Whether these standing waves result either from the interactions of multiple surface waves that travel along the membrane, or by uniformly excited modal displacement patterns of the entire TM surface is still to be determined. PMID:19328841

  2. Computer-assisted time-averaged holograms of the motion of the surface of the mammalian tympanic membrane with sound stimuli of 0.4-25 kHz.

    Rosowski, John J; Cheng, Jeffrey Tao; Ravicz, Michael E; Hulli, Nesim; Hernandez-Montes, Maria; Harrington, Ellery; Furlong, Cosme

    2009-07-01

    Time-averaged holograms describing the sound-induced motion of the tympanic membrane (TM) in cadaveric preparations from three mammalian species and one live ear were measured using opto-electronic holography. This technique allows rapid measurements of the magnitude of motion of the tympanic membrane surface at frequencies as high as 25 kHz. The holograms measured in response to low and middle-frequency sound stimuli are similar to previously reported time-averaged holograms. However, at higher frequencies (f>4 kHz), our holograms reveal unique TM surface displacement patterns that consist of highly-ordered arrangements of multiple local displacement magnitude maxima, each of which is surrounded by nodal areas of low displacement magnitude. These patterns are similar to modal patterns (two-dimensional standing waves) produced by either the interaction of surface waves traveling in multiple directions or the uniform stimulation of modes of motion that are determined by the structural properties and boundary conditions of the TM. From the ratio of the displacement magnitude peaks to nodal valleys in these apparent surface waves, we estimate a Standing Wave Ratio of at least 4 that is consistent with energy reflection coefficients at the TM boundaries of at least 0.35. It is also consistent with small losses within the uniformly stimulated modal surface waves. We also estimate possible TM surface wave speeds that vary with frequency and species from 20 to 65 m/s, consistent with other estimates in the literature. The presence of standing wave or modal phenomena has previously been intuited from measurements of TM function, but is ignored in some models of tympanic membrane function. Whether these standing waves result either from the interactions of multiple surface waves that travel along the membrane, or by uniformly excited modal displacement patterns of the entire TM surface is still to be determined.

  3. X-ray fluorescence hologram data collection with a cooled avalanche photodiode

    Hayashi, K; Matsubara, E I; Kishimoto, S; Mori, T; Tanaka, M

    2002-01-01

    A high counting rate X-ray detector with an appropriate energy resolution is desired for high quality X-ray fluorescence hologram measurements because a holographic pattern is detected as extremely small intensity variations of X-ray fluorescence on a large intensity background. A cooled avalanche photodiode (APD), which has about 10% energy resolution and is designed for a high counting rate, fits the above requirements. Reconstructed atomic images from experimental holograms using the APD system provide us a clear view of the first and second neighbor atoms around an emitter. The present result proved that a combination of this APD system and a synchrotron X-ray source enables us to measure a high quality hologram for a reasonable measurement time.

  4. Fast reconstruction of off-axis digital holograms based on digital spatial multiplexing.

    Sha, Bei; Liu, Xuan; Ge, Xiao-Lu; Guo, Cheng-Shan

    2014-09-22

    A method for fast reconstruction of off-axis digital holograms based on digital multiplexing algorithm is proposed. Instead of the existed angular multiplexing (AM), the new method utilizes a spatial multiplexing (SM) algorithm, in which four off-axis holograms recorded in sequence are synthesized into one SM function through multiplying each hologram with a tilted plane wave and then adding them up. In comparison with the conventional methods, the SM algorithm simplifies two-dimensional (2-D) Fourier transforms (FTs) of four N*N arrays into a 1.25-D FTs of one N*N arrays. Experimental results demonstrate that, using the SM algorithm, the computational efficiency can be improved and the reconstructed wavefronts keep the same quality as those retrieved based on the existed AM method. This algorithm may be useful in design of a fast preview system of dynamic wavefront imaging in digital holography.

  5. Self-interference digital holography with a geometric-phase hologram lens.

    Choi, KiHong; Yim, Junkyu; Yoo, Seunghwi; Min, Sung-Wook

    2017-10-01

    Self-interference digital holography (SIDH) is actively studied because the hologram acquisition under the incoherent illumination condition is available. The key component in this system is wavefront modulating optics, which modulates an incoming object wave into two different wavefront curvatures. In this Letter, the geometric-phase hologram lens is introduced in the SIDH system to perform as a polarization-sensitive wavefront modulator and a single-path beam splitter. This special optics has several features, such as high transparency, a modulation efficiency up to 99%, a thinness of a few millimeters, and a flat structure. The demonstration system is devised, and the numerical reconstruction results from an acquired complex hologram are presented.

  6. Depth compensating calculation method of computer-generated holograms using symmetry and similarity of zone plates

    Wei, Hui; Gong, Guanghong; Li, Ni

    2017-10-01

    Computer-generated hologram (CGH) is a promising 3D display technology while it is challenged by heavy computation load and vast memory requirement. To solve these problems, a depth compensating CGH calculation method based on symmetry and similarity of zone plates is proposed and implemented on graphics processing unit (GPU). An improved LUT method is put forward to compute the distances between object points and hologram pixels in the XY direction. The concept of depth compensating factor is defined and used for calculating the holograms of points with different depth positions instead of layer-based methods. The proposed method is suitable for arbitrary sampling objects with lower memory usage and higher computational efficiency compared to other CGH methods. The effectiveness of the proposed method is validated by numerical and optical experiments.

  7. Concurrent Exposure of Bottlenose Dolphins (Tursiops truncatus) to Multiple Algal Toxins in Sarasota Bay, Florida, USA

    Twiner, Michael J.; Fire, Spencer; Schwacke, Lori; Davidson, Leigh; Wang, Zhihong; Morton, Steve; Roth, Stephen; Balmer, Brian; Rowles, Teresa K.; Wells, Randall S.

    2011-01-01

    Sentinel species such as bottlenose dolphins (Tursiops truncatus) can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA), the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs) of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX) produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA). Over a ten-year study period (2000–2009) we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009) with 36% of all animals testing positive for brevetoxin (n = 118) and 53% positive for DA (n = 83) with several individuals (14%) testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p = 0.001) and eosinophil (p<0.001) counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health. PMID:21423740

  8. Concurrent exposure of bottlenose dolphins (Tursiops truncatus to multiple algal toxins in Sarasota Bay, Florida, USA.

    Michael J Twiner

    Full Text Available Sentinel species such as bottlenose dolphins (Tursiops truncatus can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA, the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA. Over a ten-year study period (2000-2009 we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009 with 36% of all animals testing positive for brevetoxin (n = 118 and 53% positive for DA (n = 83 with several individuals (14% testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p = 0.001 and eosinophil (p<0.001 counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health.

  9. Phase conjugation of speckle-inhomogeneous radiation in a holographic Nd:YAG laser with a short thermal hologram

    Yarovoi, V V; Kirsanov, A V

    2002-01-01

    A model of the so-called short hologram, which does not exhibit in-depth diffraction deformation of the fine speckle pattern of the recording fields, is studied. The investigation is performed by the example of a thermal hologram recorded by two speckle waves, which is the output mirror of a ring laser produced as a result of this recording. It is shown that the ability of this short hologram to select a wave conjugated to a speckle signal in the mode of the holographic laser depends both on the degree of mutual mixing of the speckles of recording beams in the hologram volume and on the effects of its saturation by the beams. The maximum accuracy of phase conjugation of speckle radiation in the holographic Nd:YAG laser achieved upon the best selection of the conjugate wave by the short thermal hologram was 93%. (nonlinear optical phenomena)

  10. Multiple-endpoint assay provides a detailed mechanistic view of responses to herbicide exposure in Chlamydomonas reinhardtii

    Nestler, Holger; Groh, Ksenia J.; Schönenberger, René; Behra, Renata; Schirmer, Kristin; Eggen, Rik I.L.; Suter, Marc J.-F.

    2012-01-01

    The release of herbicides into the aquatic environment raises concerns about potential detrimental effects on ecologically important non-target species, such as unicellular algae, necessitating ecotoxicological risk assessment. Algal toxicity tests based on growth, a commonly assessed endpoint, are integrative, and hence do not provide information about underlying toxic mechanisms and effects. This limitation may be overcome by measuring more specific biochemical and physiological endpoints. In the present work, we developed and applied a novel multiple-endpoint assay, and analyzed the effects of the herbicides paraquat, diuron and norflurazon, each representing a specific mechanism of toxic action, on the single celled green alga Chlamydomonas reinhardtii. The endpoints added to assessment of growth were pigment content, maximum and effective photosystem II quantum yield, ATP content, esterase and oxidative activity. All parameters were measured at 2, 6 and 24 h of exposure, except for growth and pigment content, which were determined after 6 and 24 h only. Effective concentrations causing 50% of response (EC50s) and lowest observable effect concentrations (LOECs) were determined for all endpoints and exposure durations where possible. The assay provided a detailed picture of the concentration- and time-dependent development of effects elicited by the analyzed herbicides, thus improving the understanding of the underlying toxic mechanisms. Furthermore, the response patterns were unique to the respective herbicide and reflected the different mechanisms of toxicity. The comparison of the endpoint responses and sensitivities revealed that several physiological and biochemical parameters reacted earlier or stronger to disturbances than growth. Overall, the presented multiple-endpoint assay constitutes a promising basis for investigating stressor and toxicant effects in green algae.

  11. Multiple-endpoint assay provides a detailed mechanistic view of responses to herbicide exposure in Chlamydomonas reinhardtii

    Nestler, Holger [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf (Switzerland); ETH Zurich, Swiss Federal Institute of Technology, Institute of Biogeochemistry and Pollutant Dynamics, Universitaetstrasse 16, 8092 Zurich (Switzerland); Groh, Ksenia J.; Schoenenberger, Rene; Behra, Renata [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf (Switzerland); Schirmer, Kristin [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf (Switzerland); ETH Zurich, Swiss Federal Institute of Technology, Institute of Biogeochemistry and Pollutant Dynamics, Universitaetstrasse 16, 8092 Zurich (Switzerland); EPF Lausanne, School of Architecture, Civil and Environmental Engineering, 1015 Lausanne (Switzerland); Eggen, Rik I.L. [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf (Switzerland); ETH Zurich, Swiss Federal Institute of Technology, Institute of Biogeochemistry and Pollutant Dynamics, Universitaetstrasse 16, 8092 Zurich (Switzerland); Suter, Marc J.-F., E-mail: suter@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf (Switzerland); ETH Zurich, Swiss Federal Institute of Technology, Institute of Biogeochemistry and Pollutant Dynamics, Universitaetstrasse 16, 8092 Zurich (Switzerland)

    2012-04-15

    The release of herbicides into the aquatic environment raises concerns about potential detrimental effects on ecologically important non-target species, such as unicellular algae, necessitating ecotoxicological risk assessment. Algal toxicity tests based on growth, a commonly assessed endpoint, are integrative, and hence do not provide information about underlying toxic mechanisms and effects. This limitation may be overcome by measuring more specific biochemical and physiological endpoints. In the present work, we developed and applied a novel multiple-endpoint assay, and analyzed the effects of the herbicides paraquat, diuron and norflurazon, each representing a specific mechanism of toxic action, on the single celled green alga Chlamydomonas reinhardtii. The endpoints added to assessment of growth were pigment content, maximum and effective photosystem II quantum yield, ATP content, esterase and oxidative activity. All parameters were measured at 2, 6 and 24 h of exposure, except for growth and pigment content, which were determined after 6 and 24 h only. Effective concentrations causing 50% of response (EC50s) and lowest observable effect concentrations (LOECs) were determined for all endpoints and exposure durations where possible. The assay provided a detailed picture of the concentration- and time-dependent development of effects elicited by the analyzed herbicides, thus improving the understanding of the underlying toxic mechanisms. Furthermore, the response patterns were unique to the respective herbicide and reflected the different mechanisms of toxicity. The comparison of the endpoint responses and sensitivities revealed that several physiological and biochemical parameters reacted earlier or stronger to disturbances than growth. Overall, the presented multiple-endpoint assay constitutes a promising basis for investigating stressor and toxicant effects in green algae.

  12. Radiation exposure control by estimation of multiplication factors for online remote radiation monitoring systems at vitrification plant

    Deokar, U.V.; Kulkarni, V.V.; Khot, A.R.; Mathew, P.; Kamlesh; Purohit, R.G.; Sarkar, P.K.

    2012-01-01

    Vitrification Plant is commissioned for vitrification of high level liquid waste (HLW) generated in nuclear fuel cycle operations by using Joule Heated Ceramic Melter first time in India. Exposure control is a major concern in operating plant. Therefore in addition to installed monitors, we have developed online remote radiation monitoring system to minimize number of entries in amber areas and to reduce the exposure to the surveyor and operator. This also helped in volume reduction of secondary waste. The reliability and accuracy of the online monitoring system is confirmed with actual measurements and by theoretical shielding calculations. The multiplication factors were estimated for remote on line monitoring of Melter Off Gas (MOG) filter, Hood filter, three exhaust filter banks, and over-pack monitoring. This paper summarizes - how the online remote monitoring system helped in saving of 128.52 person-mSv collective dose (14.28% of budgeted dose). The system also helped in the reduction of 2.6 m 3 of Cat-I waste. Our online remote monitoring system has helped the plant management to plan in advance for replacement of these filters, which resulted in considerable saving in collective dose and secondary waste

  13. Radiation exposure control by estimation of multiplication factors for online remote radiation monitoring systems at Vitrification Plant

    Deokar, Umesh V.; Kukarni, V.V.; Khot, A.R.; Mathew, P.; Kamlesh; Purohit, R.G.; Sarkar, P.K.

    2011-01-01

    Vitrification Plant is commissioned for vitrification of high-level liquid waste generated in Nuclear Fuel Cycle operations by using Joule Heated Ceramic Melter first time in India. Exposure control is a major concern in operating plant. Therefore, in addition to installed monitors, we have developed online remote radiation monitoring system to minimize number of entries in amber areas and to reduce the exposure to the surveyor and operator. This also helped in volume reduction of secondary waste. The reliability and accuracy of the online monitoring system is confirmed with actual measurements and by theoretical shielding calculations. The multiplication factors were estimated for remote online monitoring of Melter off Gas (MOG) filter, Hood filter, three exhaust filter banks, and overpack monitoring. This paper summarizes how the online remote monitoring system had helped in saving of 128.52 Person-mSv collective dose (14.28% of budgeted dose) and also there was 2.6 m 3 reduction in generation of Cat-I waste. (author)

  14. Increased Transmissibility of Leishmania donovani From the Mammalian Host to Vector Sand Flies After Multiple Exposures to Sand Fly Bites.

    Valverde, Joanna G; Paun, Andrea; Inbar, Ehud; Romano, Audrey; Lewis, Michael; Ghosh, Kashinath; Sacks, David

    2017-04-15

    Patients with active visceral leishmaniasis are important reservoirs in the anthroponotic transmission cycle of Leishmania donovani. The role of the blood or skin as a source of infection to sand flies remains unclear, and the possible effect of multiple exposures to fly bites on transmissibility has not been addressed. L. donovani-infected hamsters underwent xenodiagnoses with Lutzomyia longipalpis on the same or different sites on the abdomen on 2 consecutive days or by artificial feeding on the skin or blood. The transmission of L. donovani from sick hamsters to flies was surprisingly low (mean, 24% of fed flies). New flies fed on the same site acquired significantly more infections (mean, 61%; P Leishmania donovani. Using the hamster model of visceral disease, we demonstrate that prior exposure to bites of uninfected sand flies potentiates their ability to transmit infection to the vector. Published by Oxford University Press for the Infectious Diseases Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  15. Fabrication of computer-generated holograms using femtosecond laser direct writing.

    Berlich, René; Richter, Daniel; Richardson, Martin; Nolte, Stefan

    2016-04-15

    We demonstrate a single-step fabrication method for computer-generated holograms based on femtosecond laser direct writing. Therefore, a tightly arranged longitudinal waveguide array is directly inscribed into a transparent material. By tailoring the individual waveguide length, the phase profile of an incident laser beam can be arbitrarily adapted. The approach is verified in common borosilicate glass by inscribing a designed phase hologram, which forms the desired intensity pattern in its far field. The resulting performance is analyzed, and the potential as well as limitations of the method are discussed.

  16. The complete book of holograms how they work and how to make them

    Kasper, Joseph E

    1987-01-01

    This clear account of holography and its applications offers the novice a rigorous treatment of holographic theory and science with minimal reliance on mathematical explanation. Written in a lively, stimulating style, it explains the geometric model of holography as well as the more elaborate diffraction model, describes various types of holograms, and gives detailed instructions on how to make your own holograms and where to get the neccessary materials. Also covers current and developing applications of holographic techniques in science, industry, and the arts. Includes excellent illustrations throughout, plus a list of sources for further study.

  17. Decreased vaccine antibody titers following exposure to multiple metals and metalloids in e-waste-exposed preschool children.

    Lin, Xinjiang; Xu, Xijin; Zeng, Xiang; Xu, Long; Zeng, Zhijun; Huo, Xia

    2017-01-01

    We explored acquired immunity resulting from vaccination in 3 to 7-year-old children, chronically exposed to multiple heavy metals and metalloids, in an e-waste recycling area (Guiyu, China). Child blood levels of ten heavy metals and metalloids, including lead (Pb), arsenic (As), mercury (Hg), chromium (Cr), cadmium (Cd), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn) and selenium (Se), and seven vaccine antibodies (diphtheria, pertussis, tetanus, hepatitis B, Japanese encephalitis, polio, measles) were measured. The exposed group had higher levels of blood Pb, Mn, Cu, Zn and Cr compared to the reference group (P 10 μg/dL) and high blood Cu and Zn (upper median value of each group) to be inversely associated with seven antibody titers. Antibody titers increased with age, BMI, high blood Mn (>15 μg/L), and high blood Cd and Ni (upper median value of each group). Results suggest multiple heavy metal and metalloid exposure, especially to Pb, Zn and Cu, may be a risk factor inhibiting the development of child immunity, resulting in decreased child antibody levels against vaccines. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Challenging conventional risk assessment with respect to human exposure to multiple food contaminants in food: A case study using maize.

    Clarke, R; Connolly, L; Frizzell, C; Elliott, C T

    2015-10-01

    Mycotoxins and heavy metals are ubiquitous in the environment and contaminate many foods. The widespread use of pesticides in crop production to control disease contributes further to the chemical contamination of foods. Thus multiple chemical contaminants threaten the safety of many food commodities; hence the present study used maize as a model crop to identify the severity in terms of human exposure when multiple contaminants are present. High Content Analysis (HCA) measuring multiple endpoints was used to determine cytotoxicity of complex mixtures of mycotoxins, heavy metals and pesticides. Endpoints included nuclear intensity (NI), nuclear area (NA), plasma membrane permeability (PMP), mitochondrial membrane potential (MMP) and mitochondrial mass (MM). At concentrations representing legal limits of each individual contaminant in maize (3ng/ml ochratoxin A (OTA), 1μg/ml fumonisin B1 (FB1), 2ng/ml aflatoxin B1 (AFB1), 100ng/ml cadmium (Cd), 150ng/ml arsenic (As), 50ng/ml chlorpyrifos (CP) and 5μg/ml pirimiphos methyl (PM), the mixtures (tertiary mycotoxins plus Cd/As) and (tertiary mycotoxins plus Cd/As/CP/PM) were cytotoxic for NA and MM endpoints with a difference of up to 13.6% (p≤0.0001) and 12% (p≤0.0001) respectively from control values. The most cytotoxic mixture was (tertiary mycotoxins plus Cd/As/CP/PM) across all 4 endpoints (NA, NI, MM and MMP) with increases up to 61.3%, 23.0%, 61.4% and 36.3% (p≤0.0001) respectively. Synergy was evident for two endpoints (NI and MM) at concentrations contaminating maize above legal limits, with differences between expected and measured values of (6.2-12.4% (p≤0.05-p≤0.001) and 4.5-12.3% (p≤0.05-p≤0.001) for NI and MM, respectively. The study introduces for the first time, a holistic approach to identify the impact in terms of toxicity to humans when multiple chemical contaminants are present in foodstuffs. Governmental regulatory bodies must begin to contemplate how to safeguard the population when

  19. A non-iterative twin image elimination method with two in-line digital holograms

    Kim, Jongwu; Lee, Heejung; Jeon, Philjun; Kim, Dug Young

    2018-02-01

    We propose a simple non-iterative in-line holographic measurement method which can effectively eliminate a twin image in digital holographic 3D imaging. It is shown that a twin image can be effectively eliminated with only two measured holograms by using a simple numerical propagation algorithm and arithmetic calculations.

  20. Stereo perception of reconstructions of digital holograms of real-world objects

    Lehtimaeki, Taina M; Saeaeskilahti, Kirsti; Naesaenen, Risto [University of Oulu, Oulu Southern Institute, Ylivieska (Finland); Naughton, Thomas J, E-mail: taina.lehtimaki@oulu.f [Department of Computer Science, National University of Ireland Maynooth (Ireland)

    2010-02-01

    In digital holography a 3D scene is captured optically and often the perspectives are reconstructed numerically. In this study we digitally process the holograms to allow them to be displayed on autostereoscopic displays. This study is conducted by subjective visual perception experiments comparing single reconstructed images from left and right perspective to the resulting stereo image.

  1. Infrared Testing of the Wide-field Infrared Survey Telescope Grism Using Computer Generated Holograms

    Dominguez, Margaret Z.; Content, David A.; Gong, Qian; Griesmann, Ulf; Hagopian, John G.; Marx, Catherine T; Whipple, Arthur L.

    2017-01-01

    Infrared Computer Generated Holograms (CGHs) were designed, manufactured and used to measure the performance of the grism (grating prism) prototype which includes testing Diffractive Optical Elements (DOE). The grism in the Wide Field Infrared Survey Telescope (WFIRST) will allow the surveying of a large section of the sky to find bright galaxies.

  2. Modeling of light-emitting diode wavefronts for the optimization of transmission holograms.

    Karthaus, Daniela; Giehl, Markus; Sandfuchs, Oliver; Sinzinger, Stefan

    2017-06-20

    The objective of applying transmission holograms in automotive headlamp systems requires the adaptation of holograms to divergent and polychromatic light sources like light-emitting diodes (LEDs). In this paper, four different options to describe the scalar light waves emitted by a typical automotive LED are regarded. This includes a new approach to determine the LED's wavefront from interferometric measurements. Computer-generated holograms are designed considering the different LED approximations and recorded into a photopolymer. The holograms are reconstructed with the LED and the resulting images are analyzed to evaluate the quality of the wave descriptions. In this paper, we show that our presented new approach leads to better results in comparison to other wave descriptions. The enhancement is evaluated by the correlation between reconstructed and ideal images. In contrast to the next best approximation, a spherical wave, the correlation coefficient increased by 0.18% at 532 nm, 1.69% at 590 nm, and 0.75% at 620 nm.

  3. Incoherent digital holograms acquired by interferenceless coded aperture correlation holography system without refractive lenses.

    Kumar, Manoj; Vijayakumar, A; Rosen, Joseph

    2017-09-14

    We present a lensless, interferenceless incoherent digital holography technique based on the principle of coded aperture correlation holography. The acquired digital hologram by this technique contains a three-dimensional image of some observed scene. Light diffracted by a point object (pinhole) is modulated using a random-like coded phase mask (CPM) and the intensity pattern is recorded and composed as a point spread hologram (PSH). A library of PSHs is created using the same CPM by moving the pinhole to all possible axial locations. Intensity diffracted through the same CPM from an object placed within the axial limits of the PSH library is recorded by a digital camera. The recorded intensity this time is composed as the object hologram. The image of the object at any axial plane is reconstructed by cross-correlating the object hologram with the corresponding component of the PSH library. The reconstruction noise attached to the image is suppressed by various methods. The reconstruction results of multiplane and thick objects by this technique are compared with regular lens-based imaging.

  4. Effect of masking phase-only holograms on the quality of reconstructed images.

    Deng, Yuanbo; Chu, Daping

    2016-04-20

    A phase-only hologram modulates the phase of the incident light and diffracts it efficiently with low energy loss because of the minimum absorption. Much research attention has been focused on how to generate phase-only holograms, and little work has been done to understand the effect and limitation of their partial implementation, possibly due to physical defects and constraints, in particular as in the practical situations where a phase-only hologram is confined or needs to be sliced or tiled. The present study simulates the effect of masking phase-only holograms on the quality of reconstructed images in three different scenarios with different filling factors, filling positions, and illumination intensity profiles. Quantitative analysis confirms that the width of the image point spread function becomes wider and the image quality decreases, as expected, when the filling factor decreases, and the image quality remains the same for different filling positions as well. The width of the image point spread function as derived from different filling factors shows a consistent behavior to that as measured directly from the reconstructed image, especially as the filling factor becomes small. Finally, mask profiles of different shapes and intensity distributions are shown to have more complicated effects on the image point spread function, which in turn affects the quality and textures of the reconstructed image.

  5. Stereo perception of reconstructions of digital holograms of real-world objects

    Lehtimaeki, Taina M; Saeaeskilahti, Kirsti; Naesaenen, Risto; Naughton, Thomas J

    2010-01-01

    In digital holography a 3D scene is captured optically and often the perspectives are reconstructed numerically. In this study we digitally process the holograms to allow them to be displayed on autostereoscopic displays. This study is conducted by subjective visual perception experiments comparing single reconstructed images from left and right perspective to the resulting stereo image.

  6. A multi-nuclide approach to quantify long-term erosion rates and exposure history through multiple glacial-interglacial cycles

    Strunk, Astrid; Larsen, Nicolaj Krog; Knudsen, Mads Faurschou

    Cosmogenic nuclides are traditionally used to either determine the glaciation history or the denudation history of the most recent exposure period. A few studies use the cosmogenic nuclides to determine the cumulative exposure and burial durations of a sample. However, until now it has not been...... possible to resolve the complex pattern of exposure history under a fluctuating ice sheet. In this study, we quantify long-term erosion rates along with durations of multiple exposure periods in West Greenland by applying a novel Markov Chain Monte Carlo (MCMC) inversion approach to existing 10Be and 26Al....... The new MCMC approach allows us to constrain the most likely landscape history based on comparisons between simulated and measured cosmogenic nuclide concentrations. It is a fundamental assumption of the model that the exposure history at the site/location can be divided into two distinct regimes: i...

  7. Spatial analysis of concentrations of multiple air pollutants using NASA DISCOVER-AQ aircraft measurements: Implications for exposure assessment.

    Lee, Hyung Joo; Chatfield, Robert B; Bell, Michelle L

    2018-01-01

    In recent years, multipollutant approaches have been employed to investigate the association with health outcomes to better represent real-world conditions than more traditional analysis that considers a single pollutant. With regard to the exposure assessment of a mixture of air pollutants, it is critical to understand the spatial variability in multipollutant relations in order to assess their potential health implications. In this study, we investigated the spatial relations of multiple pollutant concentrations (i.e., NO x , NO y , black carbon, carbon monoxide, acetaldehyde, formaldehyde, toluene, xylenes/ethylbenzene, ozone, water-soluble organic carbon, and aerosol extinction) observed from the P-3B aircraft in the 2011 NASA field campaign in Baltimore/Washington D.C. areas during July 2011. The between-pollutant Pearson correlations and Z-scores (calculated from log-transformed concentrations) between near-highways and non-highways and between near-urban centers and non-urban centers varied by pollutant pair and space. We found generally lower correlations between NO x and other pollutants for near-highways (average r = 0.36) than for non-highways (average r = 0.41) and also for non-urban centers (average r = 0.37) than for near-urban centers (average r = 0.41). This indicated that the temporal associations between NO x and health outcomes might be less affected by other pollutants, which were also related to same health outcomes, for near-highways and non-urban centers. The analysis of between-pollutant Z-scores showed varying spatial relations for popular traffic-related pollutants with the Z-score differences of 0.43 (NO x -carbon monoxide), 0.29 (NO x -black carbon), and 0.17 (black carbon-carbon monoxide) between near-highways and non-highways. This result exhibited heterogeneous traffic-related pollutant mixtures with the proximity to highways, potentially leading to the diverse extent of health associations. Furthermore, a mixed effects model

  8. Full parallax three-dimensional computer generated hologram with occlusion effect using ray casting technique

    Zhang, Hao; Tan, Qiaofeng; Jin, Guofan

    2013-01-01

    Holographic display is capable of reconstructing the whole optical wave field of a three-dimensional (3D) scene. It is the only one among all the 3D display techniques that can produce all the depth cues. With the development of computing technology and spatial light modulators, computer generated holograms (CGHs) can now be used to produce dynamic 3D images of synthetic objects. Computation holography becomes highly complicated and demanding when it is employed to produce real 3D images. Here we present a novel algorithm for generating a full parallax 3D CGH with occlusion effect, which is an important property of 3D perception, but has often been neglected in fully computed hologram synthesis. The ray casting technique, which is widely used in computer graphics, is introduced to handle the occlusion issue of CGH computation. Horizontally and vertically distributed rays are projected from each hologram sample to the 3D objects to obtain the complex amplitude distribution. The occlusion issue is handled by performing ray casting calculations to all the hologram samples. The proposed algorithm has no restriction on or approximation to the 3D objects, and hence it can produce reconstructed images with correct shading effect and no visible artifacts. Programmable graphics processing unit (GPU) is used to perform parallel calculation. This is made possible because each hologram sample belongs to an independent operation. To demonstrate the performance of our proposed algorithm, an optical experiment is performed to reconstruct the 3D scene by using a phase-only spatial light modulator. We can easily perceive the accommodation cue by focusing our eyes on different depths of the scene and the motion parallax cue with occlusion effect by moving our eyes around. The experiment result confirms that the CGHs produced by our algorithm can successfully reconstruct 3D images with all the depth cues.

  9. Challenges in using GPUs for the real-time reconstruction of digital hologram images

    Hobson, P R; Nebrensky, J J; D, I

    2013-01-01

    In-line holography has recently made the transition from silver-halide based recording media, with laser reconstruction, to recording with large-area pixel detectors and computer-based reconstruction. This form of holographic imaging is an established technique for the study of fine particulates, such as cloud or fuel droplets, marine plankton and alluvial sediments, and enables a true 3D object field to be recorded at high resolution over a considerable depth. The move to digital holography promises rapid, if not instantaneous, feedback as it avoids the need for the time-consuming chemical development of plates or film film and a dedicated replay system, but with the growing use of video-rate holographic recording, and the desire to reconstruct fully every frame, the computational challenge becomes considerable. To replay a digital hologram a 2D FFT must be calculated for every depth slice desired in the replayed image volume. A typical hologram of ∼100 μm particles over a depth of a few hundred millimetres will require O(10 3 ) 2D FFT operations to be performed on a hologram of typically a few million pixels. In this paper we discuss the technical challenges in converting our existing reconstruction code to make efficient use of NVIDIA CUDA-based GPU cards and show how near real-time video slice reconstruction can be obtained with holograms as large as 4096 by 4096 pixels. Our performance to date for a number of different NVIDIA GPU running under both Linux and Microsoft Windows is presented. The recent availability of GPU on portable computers is discussed and a new code for interactive replay of digital holograms is presented.

  10. Radiation Exposure - Multiple Languages

    ... Rays) - 繁體中文 (Chinese, Traditional (Cantonese dialect)) PDF California Dental Association Nuclear or Radiation Emergencies - 繁體中文 (Chinese, Traditional (Cantonese dialect)) Bilingual PDF ...

  11. Faithful reconstruction of digital holograms captured by FINCH using a Hamming window function in the Fresnel propagation.

    Siegel, Nisan; Rosen, Joseph; Brooker, Gary

    2013-10-01

    Recent advances in Fresnel incoherent correlation holography (FINCH) increase the signal-to-noise ratio in hologram recording by interference of images from two diffractive lenses with focal lengths close to the image plane. Holograms requiring short reconstruction distances are created that reconstruct poorly with existing Fresnel propagation methods. Here we show a dramatic improvement in reconstructed fluorescent images when a 2D Hamming window function substituted for the disk window typically used to bound the impulse response in the Fresnel propagation. Greatly improved image contrast and quality are shown for simulated and experimentally determined FINCH holograms using a 2D Hamming window without significant loss in lateral or axial resolution.

  12. Multiple exposure and effects assessment of heavy metals in the population near mining area in South China.

    Ping Zhuang

    Full Text Available The objective of this study was to investigate the levels of Cd, Pb, Cu and Zn in the environment and several important food sources grown and consumed in the vicinity of Dabaoshan mine in Southern China, and evaluate potential health risks among local residents. The Cd, Pb, Cu and Zn concentrations of arable soils and well water near the mines exceeded the quality standard values. The concentrations of Cd and Pb in some food crops (rice grain, vegetable and soybean samples were significantly higher than the maximum permissible level. The Cd and Pb concentrations in half of the chicken and fish meat samples were higher than the national standard. The residents living near Dabaoshan mine had higher Cd and Pb levels in hair than those of a non-exposed population. The intake of rice was identified as a major contributor to the estimated daily intake of these metals by the residents. The hazard index values for adults and children were 10.25 and 11.11, respectively, with most of the estimated risks coming from the intake of home-grown rice and vegetables. This study highlights the importance of multiple pathways in studying health risk assessment of heavy metal exposure in China.

  13. Oxidative responsiveness to multiple stressors in the key Antarctic species, Adamussium colbecki: Interactions between temperature, acidification and cadmium exposure.

    Benedetti, Maura; Lanzoni, Ilaria; Nardi, Alessandro; d'Errico, Giuseppe; Di Carlo, Marta; Fattorini, Daniele; Nigro, Marco; Regoli, Francesco

    2016-10-01

    High-latitude marine ecosystems are ranked to be among the most sensitive regions to climate change since highly stenothermal and specially adapted organisms might be seriously affected by global warming and ocean acidification. The present investigation was aimed to provide new insights on the sensitivity to such environmental stressors in the key Antarctic species, Adamussium colbecki, focussing also on their synergistic effects with cadmium exposure, naturally abundant in this area for upwelling phenomena. Scallops were exposed for 2 weeks to various combinations of Cd (0 and 40 μgL-1), pH (8.05 and 7.60) and temperature (-1 and +1 °C). Beside Cd bioaccumulation, a wide panel of early warning biomarkers were analysed in digestive glands and gills including levels of metallothioneins, individual antioxidants and total oxyradical scavenging capacity, onset of oxidative cell damage like lipid peroxidation, lysosomal stability, DNA integrity and peroxisomal proliferation. Results indicated reciprocal interactions between multiple stressors and their elaboration by a quantitative hazard model based on the relevance and magnitude of effects, highlighted a different sensitivity of analysed tissues. Due to cellular adaptations to high basal Cd content, digestive gland appeared more tolerant toward other prooxidant stressors, but sensitive to variations of the metal. On the other hand, gills were more affected by various combinations of stressors occurring at higher temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. A strong adaptable autofocusing approach of off-axis infrared digital holography under different quality conditions of holograms

    Liu, Ning; Yang, Chao

    2017-01-01

    In this paper, we present an innovative autofocusing criterion for the reconstruction of infrared digital holograms. This criterion has the advantages of fast, efficient and precision when determining the reconstruction distance of off-axis digital holography. This criterion is a mean-free high frequency calculation process. We focus on the problem of mean value drifting found in previous published methods and design our new approach to solve it. Unlike the previous methods perform well only with high quality holograms, our method is effective for both high and low quality holograms. Even when hologram is degraded by destructive interference, our method still performs well. This method helps to automatically determine the precise reconstruction distance, and we are sure that this technology can be applied in industrial applications in the future.

  15. Design of transmission-type phase holograms for a compact radar-cross-section measurement range at 650 GHz.

    Noponen, Eero; Tamminen, Aleksi; Vaaja, Matti

    2007-07-10

    A design formalism is presented for transmission-type phase holograms for use in a submillimeter-wave compact radar-cross-section (RCS) measurement range. The design method is based on rigorous electromagnetic grating theory combined with conventional hologram synthesis. Hologram structures consisting of a curved groove pattern on a 320 mmx280 mm Teflon plate are designed to transform an incoming spherical wave at 650 GHz into an output wave generating a 100 mm diameter planar field region (quiet zone) at a distance of 1 m. The reconstructed quiet-zone field is evaluated by a numerical simulation method. The uniformity of the quiet-zone field is further improved by reoptimizing the goal field. Measurement results are given for a test hologram fabricated on Teflon.

  16. Control of the Rendition Wavelength Shifts of Color Lippmann Holograms Recorded in Single-layer panchromatic Silver-halide Emulsion

    ZHU Jianhua; GUO Lurong; LI Zuoyou; LIU Zhenqing

    2000-01-01

    Russian PFG-03C panchromatic ultra-high resolution silver-halide emulsion is regarded as the most successful material for the fabrication of color reflection holograms. But the lack of established and reliable processing sequences prevents its practical applications in business and everyday life. Though much attention is drawn upon the processing of PFG-03C color reflection holograms, the color desaturation is still a problem. The article describes the new processing of color holograms recorded in PFG- 03C plates which is demonstrated experimentally to have the capacity of controlling the rendition wavelength shifts and improving the color desaturation effectively. The rendition spectra of Red-Green-Blue (R. G. B. ) single-line reflection holographic gratings, and the color reflection hologram as well, are given in this paper.

  17. Computational hologram synthesis and representation on spatial light modulators for real-time 3D holographic imaging

    Reichelt, Stephan; Leister, Norbert

    2013-01-01

    In dynamic computer-generated holography that utilizes spatial light modulators, both hologram synthesis and hologram representation are essential in terms of fast computation and high reconstruction quality. For hologram synthesis, i.e. the computation step, Fresnel transform based or point-source based raytracing methods can be applied. In the encoding step, the complex wave-field has to be optimally represented by the SLM with its given modulation capability. For proper hologram reconstruction that implies a simultaneous and independent amplitude and phase modulation of the input wave-field by the SLM. In this paper, we discuss full complex hologram representation methods on SLMs by considering inherent SLM parameter such as modulation type and bit depth on their reconstruction performance such as diffraction efficiency and SNR. We review the three implementation schemes of Burckhardt amplitude-only representation, phase-only macro-pixel representation, and two-phase interference representation. Besides the optical performance we address their hardware complexity and required computational load. Finally, we experimentally demonstrate holographic reconstructions of different representation schemes as obtained by functional prototypes utilizing SeeReal's viewing-window holographic display technology. The proposed hardware implementations enable a fast encoding of complex-valued hologram data and thus will pave the way for commercial real-time holographic 3D imaging in the near future.

  18. The long persistence of pyrrolizidine alkaloid-derived DNA adducts in vivo: kinetic study following single and multiple exposures in male ICR mice.

    Zhu, Lin; Xue, Junyi; Xia, Qingsu; Fu, Peter P; Lin, Ge

    2017-02-01

    Pyrrolizidine alkaloid (PA)-containing plants are widespread in the world and the most common poisonous plants affecting livestock, wildlife, and humans. Our previous studies demonstrated that PA-derived DNA adducts can potentially be a common biological biomarker of PA-induced liver tumor formation. In order to validate the use of these PA-derived DNA adducts as a biomarker, it is necessary to understand the basic kinetics of the PA-derived DNA adducts formed in vivo. In this study, we studied the dose-dependent response and kinetics of PA-derived DNA adduct formation and removal in male ICR mice orally administered with a single dose (40 mg/kg) or multiple doses (10 mg/kg/day) of retrorsine, a representative carcinogenic PA. In the single-dose exposure, the PA-derived DNA adducts exhibited dose-dependent linearity and persisted for up to 4 weeks. The removal of the adducts following a single-dose exposure to retrorsine was biphasic with half-lives of 9 h (t 1/2α ) and 301 h (~12.5 days, t 1/2β ). In the 8-week multiple exposure study, a marked accumulation of PA-derived DNA adducts without attaining a steady state was observed. The removal of adducts after the multiple exposure also demonstrated a biphasic pattern but with much extended half-lives of 176 h (~7.33 days, t 1/2α ) and 1736 h (~72.3 days, t 1/2β ). The lifetime of PA-derived DNA adducts was more than 8 weeks following the multiple-dose treatment. The significant persistence of PA-derived DNA adducts in vivo supports their role in serving as a biomarker of PA exposure.

  19. High-efficiency photorealistic computer-generated holograms based on the backward ray-tracing technique

    Wang, Yuan; Chen, Zhidong; Sang, Xinzhu; Li, Hui; Zhao, Linmin

    2018-03-01

    Holographic displays can provide the complete optical wave field of a three-dimensional (3D) scene, including the depth perception. However, it often takes a long computation time to produce traditional computer-generated holograms (CGHs) without more complex and photorealistic rendering. The backward ray-tracing technique is able to render photorealistic high-quality images, which noticeably reduce the computation time achieved from the high-degree parallelism. Here, a high-efficiency photorealistic computer-generated hologram method is presented based on the ray-tracing technique. Rays are parallelly launched and traced under different illuminations and circumstances. Experimental results demonstrate the effectiveness of the proposed method. Compared with the traditional point cloud CGH, the computation time is decreased to 24 s to reconstruct a 3D object of 100 ×100 rays with continuous depth change.

  20. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms.

    Volkov, V V; Han, M G; Zhu, Y

    2013-11-01

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. Published by Elsevier B.V.

  1. Phase derivative method for reconstruction of slightly off-axis digital holograms.

    Guo, Cheng-Shan; Wang, Ben-Yi; Sha, Bei; Lu, Yu-Jie; Xu, Ming-Yuan

    2014-12-15

    A phase derivative (PD) method is proposed for reconstruction of off-axis holograms. In this method, a phase distribution of the tested object wave constrained within 0 to pi radian is firstly worked out by a simple analytical formula; then it is corrected to its right range from -pi to pi according to the sign characteristics of its first-order derivative. A theoretical analysis indicates that this PD method is particularly suitable for reconstruction of slightly off-axis holograms because it only requires the spatial frequency of the reference beam larger than spatial frequency of the tested object wave in principle. In addition, because the PD method belongs to a pure local method with no need of any integral operation or phase shifting algorithm in process of the phase retrieval, it could have some advantages in reducing computer load and memory requirements to the image processing system. Some experimental results are given to demonstrate the feasibility of the method.

  2. Specificity of Correlation Pattern Recognition Methods Application in Security Holograms Identity Control Apparatus

    Zlokazov, E. Yu.; Starikov, R. S.; Odinokov, S. B.; Tsyganov, I. K.; Talalaev, V. E.; Koluchkin, V. V.

    Automatic inspection of security hologram (SH) identity is highly demanded issue due high distribution of SH worldwide to protect documents such as passports, driving licenses, banknotes etc. While most of the known approaches use inspection of SH design features none of these approaches inspect the features of its surface relief that is a direct contribution to original master matrix used for these holograms production. In our previous works we represented the device that was developed to provide SH identification by processing of coherent responses of its surface elements. Most of the algorithms used in this device are based on application of correlation pattern recognition methods. The main issue of the present article is a description of these methods application specificities.

  3. Phase-only stereoscopic hologram calculation based on Gerchberg–Saxton iterative algorithm

    Xia Xinyi; Xia Jun

    2016-01-01

    A phase-only computer-generated holography (CGH) calculation method for stereoscopic holography is proposed in this paper. The two-dimensional (2D) perspective projection views of the three-dimensional (3D) object are generated by the computer graphics rendering techniques. Based on these views, a phase-only hologram is calculated by using the Gerchberg–Saxton (GS) iterative algorithm. Comparing with the non-iterative algorithm in the conventional stereoscopic holography, the proposed method improves the holographic image quality, especially for the phase-only hologram encoded from the complex distribution. Both simulation and optical experiment results demonstrate that our proposed method can give higher quality reconstruction comparing with the traditional method. (special topic)

  4. HOLRED - a machine for the replay of holograms made in a large bubble chamber

    Aderholz, M.; Allport, P.P.

    1989-09-01

    The Fermilab 15' Bubble Chamber, exposed to a beam of neutrinos generated at the Fermilab Tevatron, has been equipped with holographic optics in order to provide a high resolution view of particle interactions over a volume of several m 3 . A machine, ''Holred'', has been constructed to replay the holograms recorded. The principles of the machine and aspects of its construction and operation are described. Results are presented comparing holographic and conventional recordings of neutrino interactions. (author)

  5. Wavelet processing and digital interferometric contrast to improve reconstructions from X-ray Gabor holograms.

    Aguilar, Juan C; Misawa, Masaki; Matsuda, Kiyofumi; Suzuki, Yoshio; Takeuchi, Akihisa; Yasumoto, Masato

    2018-05-01

    In this work, the application of an undecimated wavelet transformation together with digital interferometric contrast to improve the resulting reconstructions in a digital hard X-ray Gabor holographic microscope is shown. Specifically, the starlet transform is used together with digital Zernike contrast. With this contrast, the results show that only a small set of scales from the hologram are, in effect, useful, and it is possible to enhance the details of the reconstruction.

  6. Angular selectivity asymmetry of holograms recorded in near infrared sensitive liquid crystal photopolymerizable materials

    Harbour, Steven; Galstian, Tigran; Akopyan, Rafik; Galstyan, Artur

    2004-08-01

    We have experimentally observed and theoretically explained the angular selectivity asymmetry in polymer dispersed liquid crystal holograms. Experiments are conducted in compounds with near infrared sensitivity. The coupled-wave theory is used to describe the diffraction properties of obtained anisotropic holographic gratings. Furthermore, the comparison of theory and experiments provides information about the optical axis direction that is defined by the average molecular orientation of the liquid crystal in the polymer matrix.

  7. Hologram representation of design data in an expert system knowledge base

    Shiva, S. G.; Klon, Peter F.

    1988-01-01

    A novel representational scheme for design object descriptions is presented. An abstract notion of modules and signals is developed as a conceptual foundation for the scheme. This abstraction relates the objects to the meaning of system descriptions. Anchored on this abstraction, a representational model which incorporates dynamic semantics for these objects is presented. This representational model is called a hologram scheme since it represents dual level information, namely, structural and semantic. The benefits of this scheme are presented.

  8. Method and apparatus for checking the stability of a setup for making reflection type holograms

    Lackner, H. G. (Inventor)

    1974-01-01

    A method and apparatus are described for checking the stability of a setup for recording reflection-type (white light) holograms. Two sets of interference fringes are simultaneously obtained, one giving information about coherence and stability of the setup alone and the other demonstrating coherence of the entire system, including the holographic recording plate. Special emphasis is given to the stability of the plate, due to the fact that any minute vibration might severely degrade or completely destroy the recording.

  9. Phase recovering algorithms for extended objects encoded in digitally recorded holograms

    Peng Z.

    2010-06-01

    Full Text Available The paper presents algorithms to recover the optical phase of digitally encoded holograms. Algorithms are based on the use of a numerical spherical reconstructing wave. Proof of the validity of the concept is performed through an experimental off axis digital holographic set-up. Two-color digital holographic reconstruction is also investigated. Application of the color set-up and algorithms concerns the simultaneous two-dimensional deformation measurement of an object submitted to a mechanical loading.

  10. Integral computer-generated hologram via a modified Gerchberg-Saxton algorithm

    Wu, Pei-Jung; Lin, Bor-Shyh; Chen, Chien-Yue; Huang, Guan-Syun; Deng, Qing-Long; Chang, Hsuan T

    2015-01-01

    An integral computer-generated hologram, which modulates the phase function of an object based on a modified Gerchberg–Saxton algorithm and compiles a digital cryptographic diagram with phase synthesis, is proposed in this study. When the diagram completes position demultiplexing decipherment, multi-angle elemental images can be reconstructed. Furthermore, an integral CGH with a depth of 225 mm and a visual angle of ±11° is projected through the lens array. (paper)

  11. Consensus hologram QSAR modeling for the prediction of human intestinal absorption.

    Moda, Tiago L; Andricopulo, Adriano D

    2012-04-15

    Consistent in silico models for ADME properties are useful tools in early drug discovery. Here, we report the hologram QSAR modeling of human intestinal absorption using a dataset of 638 compounds with experimental data associated. The final validated models are consistent and robust for the consensus prediction of this important pharmacokinetic property and are suitable for virtual screening applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Analysis of the Holart Report project: recording and publishing sales data for fine art holograms

    Zellerbach, Gary A.

    1995-02-01

    At Lake Forest College's Fourth International Symposium on Display Holography (July 1991), the author first formulated an idea to promote fine art holography by recording and publishing sale prices for art holograms. The idea was mentioned to several prominent artists in attendance, and the response was enthusiastic. The author formed a new company to publish the world's first journal of international art hologram sales, the Holart Report. Holart Report published four quarterly issues, beginning in May 1992. During that time, the publisher created a significant database of hologram art sales and reported tens of thousands of dollars in holographic art transactions. In February 1993 the author's new job obligations and a general lack of support for the project forced him to suspend publication of Holart Report. This paper attempts to answer serious questions surrounding the experience. What problems were encountered? What benefits, if any, did Holart provide during its short lifetime? Why were many in the holographic art community reluctant to support the project? In retrospect, what should have been done differently to ensure greater success? Lastly, the author states his belief that the idea remains feasible and valuable. The database is intact and the publishing template established. The lessons learned can be used to produce a much improved new version of Holart Report or a similar publication.

  13. Quickly Updatable Hologram Images Using Poly(N-vinyl Carbazole (PVCz Photorefractive Polymer Composite

    Wataru Sakai

    2012-08-01

    Full Text Available Quickly updatable hologram images using photorefractive (PR polymer composite based on poly(N-vinyl carbazole (PVCz is presented. PVCz is one of the pioneer materials of photoconductive polymers. PR polymer composite consists of 44 wt % of PVCz, 35 wt % of 4-azacycloheptylbenzylidene-malonitrile (7-DCST as a nonlinear optical dye, 20 wt % of carbazolylethylpropionate (CzEPA as a photoconductive plasticizer and 1 wt % of 2,4,7-trinitro-9-fluorenone (TNF as a sensitizer. PR composite gives high diffraction efficiency of 68% at E = 45 V μm−1. Response speed of optical diffraction is the key parameter for real-time 3D holographic display. The key parameter for obtaining quickly updatable holographic images is to control the glass transition temperature lower enough to enhance chromophore orientation. Object image of the reflected coin surface recorded with reference beam at 532 nm (green beam in the PR polymer composite is simultaneously reconstructed using a red probe beam at 642 nm. Instead of using a coin object, an object image produced by a computer was displayed on a spatial light modulator (SLM and used for the hologram. The reflected object beam from an SLM was interfered with a reference beam on PR polymer composite to record a hologram and simultaneously reconstructed by a red probe beam.

  14. Random-subset fitting of digital holograms for fast three-dimensional particle tracking [invited].

    Dimiduk, Thomas G; Perry, Rebecca W; Fung, Jerome; Manoharan, Vinothan N

    2014-09-20

    Fitting scattering solutions to time series of digital holograms is a precise way to measure three-dimensional dynamics of microscale objects such as colloidal particles. However, this inverse-problem approach is computationally expensive. We show that the computational time can be reduced by an order of magnitude or more by fitting to a random subset of the pixels in a hologram. We demonstrate our algorithm on experimentally measured holograms of micrometer-scale colloidal particles, and we show that 20-fold increases in speed, relative to fitting full frames, can be attained while introducing errors in the particle positions of 10 nm or less. The method is straightforward to implement and works for any scattering model. It also enables a parallelization strategy wherein random-subset fitting is used to quickly determine initial guesses that are subsequently used to fit full frames in parallel. This approach may prove particularly useful for studying rare events, such as nucleation, that can only be captured with high frame rates over long times.

  15. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms

    Volkov, V.V.; Han, M.G.; Zhu, Y.

    2013-01-01

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. - Highlights: • We propose a fringe-shifting holographic method simple enough for practical implementations. • Our new image-wave-recovery algorithm follows from exact solution of holographic equations. • With autocorrelation band removal from holograms it is possible to achieve double-resolution electron holography data free from several commonly known artifacts. • The new fringe-shifting method can reach an image wave resolution close to single fringe spacing

  16. Ionic and electronic dark decay of holograms in LiNbO3:Fe crystals

    Yang, Yunping; Nee, Ingo; Buse, Karsten; Psaltis, Demetri

    2001-01-01

    The lifetimes of nonfixed holograms in LiNbO 3 :Fe crystals with doping levels of 0.05, 0.138, and 0.25 wt% Fe 2 O 3 have been measured in the temperature range from 30 to 180 degree C. The time constants of the dark decay of holograms stored in crystals with doping levels of 0.05 and 0.25 wt% Fe 2 O 3 obey an Arrhenius-type dependence on absolute temperature T, but yield two activation energies: 1.0 and 0.28 eV, respectively. For these crystals, two different dark decay mechanisms are prevailing, one of which is identified as proton compensation and the other is due to electron tunneling between sites of Fe 2+ and Fe 3+ . The dark decay of holograms stored in crystals with the doping level of 0.138 wt% Fe 2 O 3 is the result of a combination of both effects. [copyright] 2001 American Institute of Physics

  17. Noise in off-axis type holograms including reconstruction and CCD camera parameters

    Voelkl, Edgar, E-mail: edgar.voelkl@fei.com [FEI Company, 5350 NE Dawson Creek Drive, Hillsboro, OR 97124-5793 (United States)

    2010-02-15

    Phase and amplitude images as contained in digital holograms are commonly extracted via a process called 'reconstruction'. Expressions for the expected noise in these images have been given in the past by several authors; however, the effect of the actual reconstruction process has not been fully appreciated. By starting with the Quantum Mechanical intensity distribution of the off-axis type interference pattern, then building the digital hologram on an electron-by-electron base while simultaneously reconstructing the phase/amplitude images and evaluating their noise levels, an expression is derived that consistently describes the noise in simulated and experimental phase/amplitude images and contains the reconstruction parameters. Because of the necessity to discretize the intensity distribution function, the digitization effects of an ideal CCD camera had to be included. Subsequently, this allowed a comparison between real and simulated holograms which then led to a comparison between the performance of an 'ideal' CCD camera versus a real device. It was concluded that significant improvement of the phase and amplitude noise may be obtained if CCD cameras were optimized for digitizing intensity distributions at low sampling rates.

  18. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms

    Volkov, V.V., E-mail: volkov@bnl.gov; Han, M.G.; Zhu, Y.

    2013-11-15

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. - Highlights: • We propose a fringe-shifting holographic method simple enough for practical implementations. • Our new image-wave-recovery algorithm follows from exact solution of holographic equations. • With autocorrelation band removal from holograms it is possible to achieve double-resolution electron holography data free from several commonly known artifacts. • The new fringe-shifting method can reach an image wave resolution close to single fringe spacing.

  19. Femtosecond laser ablation of transparent microphotonic devices and computer-generated holograms.

    Alqurashi, Tawfiq; Montelongo, Yunuen; Penchev, Pavel; Yetisen, Ali K; Dimov, Stefan; Butt, Haider

    2017-09-21

    Femtosecond laser ablation allows direct patterning of engineering materials in industrial settings without requiring multistage processes such as photolithography or electron beam lithography. However, femtosecond lasers have not been widely used to construct volumetric microphotonic devices and holograms with high reliability and cost efficiency. Here, a direct femtosecond laser writing process is developed to rapidly produce transmission 1D/2D gratings, Fresnel Zone Plate lenses, and computer-generated holograms. The optical properties including light transmission, angle-dependent resolution, and light polarization effects for the microphotonic devices have been characterized. Varying the depth of the microgratings from 400 nm to 1.5 μm allowed the control over their transmission intensity profile. The optical properties of the 1D/2D gratings were validated through a geometrical theory of diffraction model involving 2D phase modulation. The produced Fresnel lenses had transmission efficiency of ∼60% at normal incidence and they preserved the polarization of incident light. The computer-generated holograms had an average transmission efficiency of 35% over the visible spectrum. These microphotonic devices had wettability resistance of contact angle ranging from 44° to 125°. These devices can be used in a variety of applications including wavelength-selective filters, dynamic displays, fiber optics, and biomedical devices.

  20. High-resolution computer-generated reflection holograms with three-dimensional effects written directly on a silicon surface by a femtosecond laser.

    Wædegaard, Kristian J; Balling, Peter

    2011-02-14

    An infrared femtosecond laser has been used to write computer-generated holograms directly on a silicon surface. The high resolution offered by short-pulse laser ablation is employed to write highly detailed holograms with resolution up to 111 kpixels/mm2. It is demonstrated how three-dimensional effects can be realized in computer-generated holograms. Three-dimensional effects are visualized as a relative motion between different parts of the holographic reconstruction, when the hologram is moved relative to the reconstructing laser beam. Potential security applications are briefly discussed.

  1. Dose-Response for Multiple Biomarkers of Exposure and Genotoxic Effect Following Repeated Treatment of Rats with the Alkylating Agents, MMS and MNU.

    Ji, Zhiying; LeBaron, Matthew J; Schisler, Melissa R; Zhang, Fagen; Bartels, Michael J; Gollapudi, B Bhaskar; Pottenger, Lynn H

    2016-05-01

    The nature of the dose-response relationship for various in vivo endpoints of exposure and effect were investigated using the alkylating agents, methyl methanesulfonate (MMS) and methylnitrosourea (MNU). Six male F344 rats/group were dosed orally with 0, 0.5, 1, 5, 25 or 50mg/kg bw/day (mkd) of MMS, or 0, 0.01, 0.1, 1, 5, 10, 25 or 50 mkd of MNU, for 4 consecutive days and sacrificed 24h after the last dose. The dose-responses for multiple biomarkers of exposure and genotoxic effect were investigated. In MMS-treated rats, the hemoglobin adduct level, a systemic exposure biomarker, increased linearly with dose (r (2) = 0.9990, P agents. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. War-related trauma exposure and multiple risk behaviors among school-going adolescents in Northern Uganda: the mediating role of depression symptoms.

    Okello, James; Nakimuli-Mpungu, Etheldreda; Musisi, Seggane; Broekaert, Eric; Derluyn, Ilse

    2013-11-01

    The relationship between war-related trauma exposure, depressive symptoms and multiple risk behaviors among adolescents is less clear in sub-Saharan Africa. We analyzed data collected from a sample of school-going adolescents four years postwar. Participants completed interviews assessing various risk behaviors defined by the Youth Self Report (YSR) and a sexual risk behavior survey, and were screened for post-traumatic stress, anxiety and depression symptoms based on the Impact of Events Scale Revised (IESR) and Hopkins Symptom Checklist for Adolescents (HSCL-37A) respectively. Multivariate logistic regression was used to assess factors independently associated with multiple risk behaviors. The logistic regression model of Baron and Kenny (1986) was used to evaluate the mediating role of depression in the relationship between stressful war events and multiple risk behaviors. Of 551 participants, 139 (25%) reported multiple (three or more) risk behaviors in the past year. In the multivariate analyses, depression symptoms remained uniquely associated with multiple risk behavior after adjusting for potential confounders including socio-demographic characteristics, war-related trauma exposure variables, anxiety and post-traumatic stress symptoms. In mediation analysis, depression symptoms mediated the associations between stressful war events and multiple risk behaviors. The psychometric properties of the questionnaires used in this study are not well established in war affected African samples thus ethno cultural variation may decrease the validity of our measures. Adolescents with depression may be at a greater risk of increased engagement in multiple risk behaviors. Culturally sensitive and integrated interventions to treat and prevent depression among adolescents in post-conflict settings are urgently needed. © 2013 Elsevier B.V. All rights reserved.

  3. Simulation of recording the microwave holograms of complex objects by the near range radars

    V. V. Razevig

    2014-01-01

    Full Text Available Radar is an object-detection technology that uses radio waves to determine the presence, range, altitude, direction, or speed of objects. In the recent time, there is an increasingly arising interest to the near range microwave imaging that allows detection of the shape and, in some cases, the inner structure of the investigated objects.For design engineering and efficiency evaluation of the cutting-edge radars as well as for testing the developed recovery algorithms a set of microwave holograms of various objects obtained under different conditions is needed. Microwave holograms cannot be obtained only on the basis of the experimental researches related to the measurements of electromagnetic scattering by the real objects since such experiments are time consuming and quite expensive. Therefore, to simulate electromagnetic scattering processes via objects examination is quite a challenge.This investigation goal is to develop a computer simulation method to record the microwave holograms of complex objects by the near range radars.To specify the shape of the investigated objects, Autodesk 3ds Max (3D computer graphics program for making 3D animations, models, and images is used. At a second stage the surface of the created object is described by a set of triangular facets. While calculating the reflected field, a final representation of the object as a set of point reflectors is used. Thus, the model of single scattering, is used without taking into consideration re-reflection and cross-influence of reflectors.Methods are also described to form the focused images of the microwave holograms that allow us to obtain a function describing object reflectivity, by which in most cases an object shape can be easily recognized.A comparison of computer-simulated holograms with experimental data proves the model adequacy.The model can be used to find a dependence of the plane resolution on used frequency, step of scanning, and distance to the object and a

  4. The Relationship Between and Factors Influencing Staff Nurses' Perceptions of Nurse Manager Caring and Exposure to Workplace Bullying in Multiple Healthcare Settings.

    Olender, Lynda

    2017-10-01

    The aim of this study was to examine the relationship between, and factors influencing, staff nurse perceptions of nurse manager caring (NMC) and the perceived exposure to workplace bullying (WPB) in multiple healthcare settings. Workplace bullying is commonplace, increasing, and detrimental to the health and availability of our nursing workforce. Positive relationships between a nurse manager (NM) and staff increase staff satisfaction and reduce turnover. Still unknown, however, is whether a caring relationship between manager and staff can reduce staff nurse perception of exposure to WPB. On the basis of Watson's theory that caring is reciprocal in nature, a descriptive correlational design was used to assess 156 staff nurses' self-report of NMC and their exposure to negative acts using the Caring Factor Survey-Caring of the Manager and the Negative Acts Questionnaire-Revised instruments. There is a significant inverse relationship between NMC and exposure to WPB in the nursing workplace. Gender, work environment, and a high workload influenced these findings. This study highlights the importance of caring leadership to reduce exposure to negative behaviors. The data lend support to the idea of educating NMs regarding the application of caring behaviors to support staff at the point of care.

  5. A multiple endpoint analysis of the effects of chronic exposure to sediment contaminated with Deepwater Horizon oil on juvenile Southern flounder and their associated microbiomes

    Brown-Peterson, Nancy J.; Krasnec, Michelle; Takeshita, Ryan; Ryan, Caitlin N.; Griffitt, Kimberly J.; Lay, Claire; Mayer, Gregory D.; Bayha, Keith M.; Hawkins, William E.; Lipton, Ian; Morris, Jeffrey

    2015-01-01

    Highlights: • Juvenile southern flounder were exposed to sediment mixed with different amount of oil from the Deepwater Horizon spill. • The exposure was performed for 32 days, with growth and survival assessed throughout. • After the termination of the experiment, the survivors were examined at multiple endpoints, including histopathology and microbiome analysis. • The results indicated that the flounder were adversely affected at each endpoint examined. • Growth and survival were significantly reduced. • Histopathology found effects on gills and livers of exposed fish. • The microbiomes of the exposed fish were significantly altered by the exposure to sediment-associated oil in both gills and intestines. - Abstract: Exposure to oiled sediments can negatively impact the health of fish species. Here, we examine the effects of chronic exposure of juvenile southern flounder, Paralichthys lethostigma, to a sediment-oil mixture. Oil:sediment mixtures are persistent over time and can become bioavailable following sediment perturbation or resuspension. Juvenile flounder were exposed for 32 days under controlled laboratory conditions to five concentrations of naturally weathered Macondo MC252 oil mixed into uncontaminated, field-collected sediments. The percent composition of individual polycyclic aromatic hydrocarbons (PAHs) of the weathered oil did not change after mixing with the sediment. Spiked exposure sediments contained 0.04–395 mg/kg tPAH50 (sum of 50 individual PAH concentration measurements). Mortality increased with both exposure duration and concentration of sediment-associated PAHs, and flounder exposed to concentrations above 8 mg/kg tPAH50 showed significantly reduced growth over the course of the experiment. Evident histopathologic changes were observed in liver and gill tissues of fish exposed to more than 8 mg/kg tPAH50. All fish at these concentrations showed hepatic intravascular congestion, macrovesicular hepatic vacoulation

  6. A multiple endpoint analysis of the effects of chronic exposure to sediment contaminated with Deepwater Horizon oil on juvenile Southern flounder and their associated microbiomes

    Brown-Peterson, Nancy J., E-mail: nancy.brown-peterson@usm.edu [Department of Coastal Sciences, The University of Southern Mississippi, 703 East Beach Dr., Ocean Springs, MS 39564 (United States); Krasnec, Michelle, E-mail: MKrasnec@stratusconsulting.com [Abt Associates, 1881 Ninth Street, Suite 201, Boulder, Colorado 80302 (United States); Takeshita, Ryan, E-mail: RTakeshita@stratusconsulting.com [Abt Associates, 1881 Ninth Street, Suite 201, Boulder, Colorado 80302 (United States); Ryan, Caitlin N., E-mail: Caitlin.ryan@ttu.edu [The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Box 41163, Lubbock, TX 79409 (United States); Griffitt, Kimberly J., E-mail: kim.griffitt@gmail.com [Department of Coastal Sciences, The University of Southern Mississippi, 703 East Beach Dr., Ocean Springs, MS 39564 (United States); Lay, Claire, E-mail: claymsc@stratusconsulting.com [Abt Associates, 1881 Ninth Street, Suite 201, Boulder, Colorado 80302 (United States); Mayer, Gregory D., E-mail: greg.mayer@ttu.edu [The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Box 41163, Lubbock, TX 79409 (United States); Bayha, Keith M., E-mail: kmbayha@gmail.com [Department of Coastal Sciences, The University of Southern Mississippi, 703 East Beach Dr., Ocean Springs, MS 39564 (United States); Hawkins, William E., E-mail: william.hawkins@usm.edu [Department of Coastal Sciences, The University of Southern Mississippi, 703 East Beach Dr., Ocean Springs, MS 39564 (United States); Lipton, Ian, E-mail: ianlipton@stratusconsulting.com [Abt Associates, 1881 Ninth Street, Suite 201, Boulder, Colorado 80302 (United States); Morris, Jeffrey, E-mail: JMorrisMSCanyon252@stratusconsulting.com [Abt Associates, 1881 Ninth Street, Suite 201, Boulder, Colorado 80302 (United States); and others

    2015-08-15

    Highlights: • Juvenile southern flounder were exposed to sediment mixed with different amount of oil from the Deepwater Horizon spill. • The exposure was performed for 32 days, with growth and survival assessed throughout. • After the termination of the experiment, the survivors were examined at multiple endpoints, including histopathology and microbiome analysis. • The results indicated that the flounder were adversely affected at each endpoint examined. • Growth and survival were significantly reduced. • Histopathology found effects on gills and livers of exposed fish. • The microbiomes of the exposed fish were significantly altered by the exposure to sediment-associated oil in both gills and intestines. - Abstract: Exposure to oiled sediments can negatively impact the health of fish species. Here, we examine the effects of chronic exposure of juvenile southern flounder, Paralichthys lethostigma, to a sediment-oil mixture. Oil:sediment mixtures are persistent over time and can become bioavailable following sediment perturbation or resuspension. Juvenile flounder were exposed for 32 days under controlled laboratory conditions to five concentrations of naturally weathered Macondo MC252 oil mixed into uncontaminated, field-collected sediments. The percent composition of individual polycyclic aromatic hydrocarbons (PAHs) of the weathered oil did not change after mixing with the sediment. Spiked exposure sediments contained 0.04–395 mg/kg tPAH50 (sum of 50 individual PAH concentration measurements). Mortality increased with both exposure duration and concentration of sediment-associated PAHs, and flounder exposed to concentrations above 8 mg/kg tPAH50 showed significantly reduced growth over the course of the experiment. Evident histopathologic changes were observed in liver and gill tissues of fish exposed to more than 8 mg/kg tPAH50. All fish at these concentrations showed hepatic intravascular congestion, macrovesicular hepatic vacoulation

  7. Assessing human variability in kinetics for exposures to multiple environmental chemicals: a physiologically based pharmacokinetic modeling case study with dichloromethane, benzene, toluene, ethylbenzene, and m-xylene.

    Valcke, Mathieu; Haddad, Sami

    2015-01-01

    The objective of this study was to compare the magnitude of interindividual variability in internal dose for inhalation exposure to single versus multiple chemicals. Physiologically based pharmacokinetic models for adults (AD), neonates (NEO), toddlers (TODD), and pregnant women (PW) were used to simulate inhalation exposure to "low" (RfC-like) or "high" (AEGL-like) air concentrations of benzene (Bz) or dichloromethane (DCM), along with various levels of toluene alone or toluene with ethylbenzene and xylene. Monte Carlo simulations were performed and distributions of relevant internal dose metrics of either Bz or DCM were computed. Area under the blood concentration of parent compound versus time curve (AUC)-based variability in AD, TODD, and PW rose for Bz when concomitant "low" exposure to mixtures of increasing complexities occurred (coefficient of variation (CV) = 16-24%, vs. 12-15% for Bz alone), but remained unchanged considering DCM. Conversely, AUC-based CV in NEO fell (15 to 5% for Bz; 12 to 6% for DCM). Comparable trends were observed considering production of metabolites (AMET), except for NEO's CYP2E1-mediated metabolites of Bz, where an increased CV was observed (20 to 71%). For "high" exposure scenarios, Cmax-based variability of Bz and DCM remained unchanged in AD and PW, but decreased in NEO (CV= 11-16% to 2-6%) and TODD (CV= 12-13% to 7-9%). Conversely, AMET-based variability for both substrates rose in every subpopulation. This study analyzed for the first time the impact of multiple exposures on interindividual variability in toxicokinetics. Evidence indicates that this impact depends upon chemical concentrations and biochemical properties, as well as the subpopulation and internal dose metrics considered.

  8. Interferenceless coded aperture correlation holography-a new technique for recording incoherent digital holograms without two-wave interference.

    Vijayakumar, A; Rosen, Joseph

    2017-06-12

    Recording digital holograms without wave interference simplifies the optical systems, increases their power efficiency and avoids complicated aligning procedures. We propose and demonstrate a new technique of digital hologram acquisition without two-wave interference. Incoherent light emitted from an object propagates through a random-like coded phase mask and recorded directly without interference by a digital camera. In the training stage of the system, a point spread hologram (PSH) is first recorded by modulating the light diffracted from a point object by the coded phase masks. At least two different masks should be used to record two different intensity distributions at all possible axial locations. The various recorded patterns at every axial location are superposed in the computer to obtain a complex valued PSH library cataloged to its axial location. Following the training stage, an object is placed within the axial boundaries of the PSH library and the light diffracted from the object is once again modulated by the same phase masks. The intensity patterns are recorded and superposed exactly as the PSH to yield a complex hologram of the object. The object information at any particular plane is reconstructed by a cross-correlation between the complex valued hologram and the appropriate element of the PSH library. The characteristics and the performance of the proposed system were compared with an equivalent regular imaging system.

  9. Gene expression profiling in persons with multiple chemical sensitivity before and after a controlled n-butanol exposure session

    Dantoft, Thomas Meinertz; Skovbjerg, Sine; Andersson, Linus

    2017-01-01

    was that unexposed and symptom-free MCS participants have similar gene expression patterns to controls and a second hypothesis that MCS participants can be separated from controls based on differential gene expression upon a controlled n-butanol exposure. Participants were exposed to 3.7 ppm n-butanol while seated...... min after being exposed to and 4 hours after the exposure. Participants suffering from MCS and healthy controls were recruited through advertisement at public places and in a local newspaper. 36 participants who considered themselves sensitive were prescreened for eligibility. 18 sensitive persons...... displayed similar gene expression levels both at baseline and after the exposure and the computed AUC values were likewise comparable between the 2 groups. The intragroup variation in expression levels among MCS participants was noticeably greater than the controls. MCS participants and controls have...

  10. Hepatic toxicology following single and multiple exposure of engineered nanomaterials utilising a novel primary human 3D liver microtissue model

    Kermanizadeh, Ali; Løhr, Mille; Roursgaard, Martin

    2014-01-01

    BackgroundThe liver has a crucial role in metabolic homeostasis as well as being the principal detoxification centre of the body, removing xenobiotics and waste products which could potentially include some nanomaterials (NM). With the ever increasing public and occupational exposure associated...... with accumulative production of nanomaterials, there is an urgent need to consider the possibility of detrimental health consequences of engineered NM exposure. It has been shown that exposure via inhalation, intratracheal instillation or ingestion can result in NM translocation to the liver. Traditional in vitro...... or ex vivo hepatic nanotoxicology models are often limiting and/or troublesome (i.e. reduced metabolism enzymes, lacking important cell populations, unstable with very high variability, etc.).MethodsIn order to rectify these issues and for the very first time we have utilised a 3D human liver...

  11. Patterns of Multiple Risk Exposures for Low Receptive Vocabulary Growth 4-8 Years in the Longitudinal Study of Australian Children.

    Daniel Christensen

    Full Text Available Risk exposures and predictions of child development outcomes typically estimate the independent effects of individual exposures. As a rule though, children are not exposed piecemeal to individual or single risks but, rather, they are exposed to clusters of risk. Many of these clusters of risks are better thought of as comprising a developmental "circumstance" with a substantial duration, over which period, additional risk exposures also accumulate. In this paper we examined the distribution of 16 single risk exposures for low language ability using latent class analysis across a sample of approximately 4000 children from the Longitudinal Study of Australian Children. The best fitting model identified six distinct classes. 46% of children were in a Developmentally Enabled group, 20% were in a group typified as Working Poor families, 10% of children were in group typified as Overwhelmed group, 9% of children were in a group defined by Child Developmental Delay, 8% of children were in a group defined by Low Human Capital, and 7% of children were in a group defined by Resource Poor non-English Speaking background families. These groups had quantitatively and qualitatively distinct patterns of risk factors and showed different onward trajectories of receptive vocabulary. Our results demonstrate a range of multiple risk profiles in a population-representative sample of Australian children and highlight the mix of risk factors faced by children. Children with distinct patterns of risk factors have different onward trajectories of receptive vocabulary development.

  12. Portable waveguide display system with a large field of view by integrating freeform elements and volume holograms.

    Han, Jian; Liu, Juan; Yao, Xincheng; Wang, Yongtian

    2015-02-09

    A compact waveguide display system integrating freeform elements and volume holograms is presented here for the first time. The use of freeform elements can broaden the field of view, which limits the applications of a holographic waveguide. An optimized system can achieve a diagonal field of view of 45° when the thickness of the waveguide planar is 3mm. Freeform-elements in-coupler and the volume holograms out-coupler were designed in detail in our study, and the influence of grating configurations on diffraction efficiency was analyzed thoroughly. The off-axis aberrations were well compensated by the in-coupler and the diffraction efficiency of the optimized waveguide display system could reach 87.57%. With integrated design, stability and reliability of this monochromatic display system were achieved and the alignment of the system was easily controlled by the record of the volume holograms, which makes mass production possible.

  13. Comparative analysis of the modified enclosed energy metric for self-focusing holograms from digital lensless holographic microscopy.

    Trujillo, Carlos; Garcia-Sucerquia, Jorge

    2015-06-01

    A comparative analysis of the performance of the modified enclosed energy (MEE) method for self-focusing holograms recorded with digital lensless holographic microscopy is presented. Notwithstanding the MEE analysis previously published, no extended analysis of its performance has been reported. We have tested the MEE in terms of the minimum axial distance allowed between the set of reconstructed holograms to search for the focal plane and the elapsed time to obtain the focused image. These parameters have been compared with those for some of the already reported methods in the literature. The MEE achieves better results in terms of self-focusing quality but at a higher computational cost. Despite its longer processing time, the method remains within a time frame to be technologically attractive. Modeled and experimental holograms have been utilized in this work to perform the comparative study.

  14. Laser memory (hologram) and coincident redundant multiplex memory (CRM-memory)

    Ostojic, Branko

    1975-01-01

    It is shown that besides the memory which remembers the object by memorising of the phases of the interferenting waves of the light (i.e. hologram) it is possible to construct the memory which remembers the object by memorising of the phases of the interferenting impulses (CFM-memory). It is given the mathematical description of the memory, based on the experimental model. Although in the paper only the technical aspect of CRM memory is given. It is mentioned the possibility that the human memory has the same principle and that the invention of CRM memory is due to cybernetical analysis of the system human eye-visual cortex

  15. Topological transformation of fractional optical vortex beams using computer generated holograms

    Maji, Satyajit; Brundavanam, Maruthi M.

    2018-04-01

    Optical vortex beams with fractional topological charges (TCs) are generated by the diffraction of a Gaussian beam using computer generated holograms embedded with mixed screw-edge dislocations. When the input Gaussian beam has a finite wave-front curvature, the generated fractional vortex beams show distinct topological transformations in comparison to the integer charge optical vortices. The topological transformations at different fractional TCs are investigated through the birth and evolution of the points of phase singularity, the azimuthal momentum transformation, occurrence of critical points in the transverse momentum and the vorticity around the singular points. This study is helpful to achieve better control in optical micro-manipulation applications.

  16. Studying the Recent Improvements in Holograms for Three-Dimensional Display

    Hamed Abbasi

    2014-01-01

    Full Text Available Displayers tend to become three-dimensional. The most advantage of holographic 3D displays is the possibility to observe 3D images without using glasses. The quality of created images by this method has surprised everyone. In this paper, the experimental steps of making a transmission hologram have been mentioned. In what follows, current advances of this science-art will be discussed. The aim of this paper is to study the recent improvements in creating three-dimensional images and videos by means of holographic techniques. In the last section we discuss the potentials of holography to be applied in future.

  17. Full-color large-scaled computer-generated holograms using RGB color filters.

    Tsuchiyama, Yasuhiro; Matsushima, Kyoji

    2017-02-06

    A technique using RGB color filters is proposed for creating high-quality full-color computer-generated holograms (CGHs). The fringe of these CGHs is composed of more than a billion pixels. The CGHs reconstruct full-parallax three-dimensional color images with a deep sensation of depth caused by natural motion parallax. The simulation technique as well as the principle and challenges of high-quality full-color reconstruction are presented to address the design of filter properties suitable for large-scaled CGHs. Optical reconstructions of actual fabricated full-color CGHs are demonstrated in order to verify the proposed techniques.

  18. Three-dimensional weight-accumulation algorithm for generating multiple excitation spots in fast optical stimulation

    Takiguchi, Yu; Toyoda, Haruyoshi

    2017-11-01

    We report here an algorithm for calculating a hologram to be employed in a high-access speed microscope for observing sensory-driven synaptic activity across all inputs to single living neurons in an intact cerebral cortex. The system is based on holographic multi-beam generation using a two-dimensional phase-only spatial light modulator to excite multiple locations in three dimensions with a single hologram. The hologram was calculated with a three-dimensional weighted iterative Fourier transform method using the Ewald sphere restriction to increase the calculation speed. Our algorithm achieved good uniformity of three dimensionally generated excitation spots; the standard deviation of the spot intensities was reduced by a factor of two compared with a conventional algorithm.

  19. Multiple-Strain Approach and Probabilistic Modeling of Consumer Habits in Quantitative Microbial Risk Assessment: A Quantitative Assessment of Exposure to Staphylococcal Enterotoxin A in Raw Milk.

    Crotta, Matteo; Rizzi, Rita; Varisco, Giorgio; Daminelli, Paolo; Cunico, Elena Cosciani; Luini, Mario; Graber, Hans Ulrich; Paterlini, Franco; Guitian, Javier

    2016-03-01

    Quantitative microbial risk assessment (QMRA) models are extensively applied to inform management of a broad range of food safety risks. Inevitably, QMRA modeling involves an element of simplification of the biological process of interest. Two features that are frequently simplified or disregarded are the pathogenicity of multiple strains of a single pathogen and consumer behavior at the household level. In this study, we developed a QMRA model with a multiple-strain approach and a consumer phase module (CPM) based on uncertainty distributions fitted from field data. We modeled exposure to staphylococcal enterotoxin A in raw milk in Lombardy; a specific enterotoxin production module was thus included. The model is adaptable and could be used to assess the risk related to other pathogens in raw milk as well as other staphylococcal enterotoxins. The multiplestrain approach, implemented as a multinomial process, allowed the inclusion of variability and uncertainty with regard to pathogenicity at the bacterial level. Data from 301 questionnaires submitted to raw milk consumers were used to obtain uncertainty distributions for the CPM. The distributions were modeled to be easily updatable with further data or evidence. The sources of uncertainty due to the multiple-strain approach and the CPM were identified, and their impact on the output was assessed by comparing specific scenarios to the baseline. When the distributions reflecting the uncertainty in consumer behavior were fixed to the 95th percentile, the risk of exposure increased up to 160 times. This reflects the importance of taking into consideration the diversity of consumers' habits at the household level and the impact that the lack of knowledge about variables in the CPM can have on the final QMRA estimates. The multiple-strain approach lends itself to use in other food matrices besides raw milk and allows the model to better capture the complexity of the real world and to be capable of geographical

  20. The use of discriminant analysis for evaluation of early-response multiple biomarkers of radiation exposure using non-human primate 6-Gy whole-body radiation model

    Ossetrova, N.I. [Armed Forces Radiobiology Research Institute, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States)], E-mail: ossetrova@afrri.usuhs.mil; Farese, A.M.; MacVittie, T.J. [Marlene and Stewart Greenebaum Cancer Center, Bressler Research Building, Room 7-039, University of Maryland-Baltimore, 655 West Baltimore Street, Baltimore, MD 21201 (United States); Manglapus, G.L.; Blakely, W.F. [Armed Forces Radiobiology Research Institute, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States)

    2007-07-15

    The present need to rapidly identify severely irradiated individuals in mass-casualty and population-monitoring scenarios prompted an evaluation of potential protein biomarkers to provide early diagnostic information after exposure. The level of specific proteins measured using immunodiagnostic technologies may be useful as protein biomarkers to provide early diagnostic information for acute radiation exposures. Herein we present results from on-going studies using a non-human primate (NHP) 6-Gy X-rays ( 0.13Gymin{sup -1}) whole-body radiation model. Protein targets were measured by enzyme-linked immunosorbent assay (ELISA) in blood plasma before, 1, and 2 days after exposure. Exposure of 10 NHPs to 6 Gy resulted in the up-regulation of plasma levels of (a) p21 WAF1/CIP1, (b) interleukin 6 (IL-6), (c) tissue enzyme salivary {alpha}-amylase, and (d) C-reactive protein. Data presented show the potential utility of protein biomarkers selected from distinctly different pathways to detect radiation exposure. A correlation analysis demonstrated strong correlations among different combinations of four candidate radiation-responsive blood protein biomarkers. Data analyzed with use of multivariate discriminant analysis established very successful separation of NHP groups: 100% discrimination power for animals with correct classification for separation between groups before and 1 day after irradiation, and 95% discrimination power for separation between groups before and 2 days after irradiation. These results also demonstrate proof-in-concept that multiple protein biomarkers provide early diagnostic information to the medical community, along with classical biodosimetric methodologies, to effectively manage radiation casualty incidents.

  1. Detection of viability of micro-algae cells by optofluidic hologram pattern.

    Wang, Junsheng; Yu, Xiaomei; Wang, Yanjuan; Pan, Xinxiang; Li, Dongqing

    2018-03-01

    A rapid detection of micro-algae activity is critical for analysis of ship ballast water. A new method for detecting micro-algae activity based on lens-free optofluidic holographic imaging is presented in this paper. A compact lens-free optofluidic holographic imaging device was developed. This device is mainly composed of a light source, a small through-hole, a light propagation module, a microfluidic chip, and an image acquisition and processing module. The excited light from the light source passes through a small hole to reach the surface of the micro-algae cells in the microfluidic chip, and a holographic image is formed by the diffraction light of surface of micro-algae cells. The relation between the characteristics in the hologram pattern and the activity of micro-algae cells was investigated by using this device. The characteristics of the hologram pattern were extracted to represent the activity of micro-algae cells. To demonstrate the accuracy of the presented method and device, four species of micro-algae cells were employed as the test samples and the comparison experiments between the alive and dead cells of four species of micro-algae were conducted. The results show that the developed method and device can determine live/dead microalgae cells accurately.

  2. Comparison of the different approaches to generate holograms from data acquired with a Kinect sensor

    Kang, Ji-Hoon; Leportier, Thibault; Ju, Byeong-Kwon; Song, Jin Dong; Lee, Kwang-Hoon; Park, Min-Chul

    2017-05-01

    Data of real scenes acquired in real-time with a Kinect sensor can be processed with different approaches to generate a hologram. 3D models can be generated from a point cloud or a mesh representation. The advantage of the point cloud approach is that computation process is well established since it involves only diffraction and propagation of point sources between parallel planes. On the other hand, the mesh representation enables to reduce the number of elements necessary to represent the object. Then, even though the computation time for the contribution of a single element increases compared to a simple point, the total computation time can be reduced significantly. However, the algorithm is more complex since propagation of elemental polygons between non-parallel planes should be implemented. Finally, since a depth map of the scene is acquired at the same time than the intensity image, a depth layer approach can also be adopted. This technique is appropriate for a fast computation since propagation of an optical wavefront from one plane to another can be handled efficiently with the fast Fourier transform. Fast computation with depth layer approach is convenient for real time applications, but point cloud method is more appropriate when high resolution is needed. In this study, since Kinect can be used to obtain both point cloud and depth map, we examine the different approaches that can be adopted for hologram computation and compare their performance.

  3. Occlusion culling and calculation for a computer generated hologram using spatial frequency index method

    Zhao, Kai; Yan, Xingpeng; Jiang, Xiaoyu; Huang, Yingqing

    2015-01-01

    A spatial frequency index method is proposed to cull occlusion and generate a hologram. Object points with the same spatial frequency are put into a set for their mutual occlusion. The hidden surfaces of the three-dimensional (3D) scene are quickly removed through culling the object points that are furthest from the hologram plane in the set. The phases of plane wave, which are only interrelated with the spatial frequencies, are precomputed and stored in a table. According to the spatial frequency of the object points, the phases of plane wave for generating fringes are obtained directly from the table. Three 3D scenes are chosen to verify the spatial frequency index method. Both numerical simulation and optical reconstruction are performed. Experimental results demonstrate that the proposed method can cull the hidden surfaces of the 3D scene correctly. The occlusion effect of the 3D scene can be well reproduced. The computational speed is better than that obtained using conventional methods but is still time-consuming. (paper)

  4. Adaptive interferometry based on dynamic reflective holograms in cubic photorefractive crystals

    Kolegov, A A; Shandarov, S M; Simonova, G V; Kabanova, L A; Burimov, Nikolai I; Shmakov, S S; Bykov, V I; Kargin, Yu F

    2011-09-30

    The characteristics of a holographic interferometer, which is based on the interaction of counterpropagating light waves on reflective holograms in cubic photorefractive sillenite crystals of the (100) cut and designed for measuring surface vibration spectra from specularly reflecting objects, have been theoretically analysed and experimentally studied. The experiments showed that an interferometer of this type, based on an Bi{sub 12}TiO{sub 20} : Fe,Cu crystal, makes it possible to measure vibrations with an amplitude of 5 pm. An analysis performed with allowance for the shot and thermal noise of the photodetector showed that vibrations with an amplitude below 1 pm can be measured. A model is proposed to describe the experimentally found strong temperature dependence of the light interaction on reflection holograms in a Bi{sub 12}TiO{sub 20} : Ca crystal. This model takes into account the influence of temperature on the photoinduced charge redistribution over deep donor and shallow trap centres, as well as the drift of the interference pattern in the crystal due to the thermooptical effect and linear expansion of the crystal.

  5. Adult exposure to ocean acidification is maladaptive for larvae of the Sydney rock oyster Saccostrea glomerata in the presence of multiple stressors.

    Parker, Laura M; O'Connor, Wayne A; Byrne, Maria; Coleman, Ross A; Virtue, Patti; Dove, Michael; Gibbs, Mitchell; Spohr, Lorraine; Scanes, Elliot; Ross, Pauline M

    2017-02-01

    Parental effects passed from adults to their offspring have been identified as a source of rapid acclimation that may allow marine populations to persist as our surface oceans continue to decrease in pH. Little is known, however, whether parental effects are beneficial for offspring in the presence of multiple stressors. We exposed adults of the oyster Saccostrea glomerata to elevated CO 2 and examined the impacts of elevated CO 2 (control = 392; 856 µatm) combined with elevated temperature (control = 24; 28°C), reduced salinity (control = 35; 25) and reduced food concentration (control = full; half diet) on their larvae. Adult exposure to elevated CO 2 had a positive impact on larvae reared at elevated CO 2 as a sole stressor, which were 8% larger and developed faster at elevated CO 2 compared with larvae from adults exposed to ambient CO 2 These larvae, however, had significantly reduced survival in all multistressor treatments. This was particularly evident for larvae reared at elevated CO 2 combined with elevated temperature or reduced food concentration, with no larvae surviving in some treatment combinations. Larvae from CO 2 -exposed adults had a higher standard metabolic rate. Our results provide evidence that parental exposure to ocean acidification may be maladaptive when larvae experience multiple stressors. © 2017 The Author(s).

  6. Blending Multiple Nitrogen Dioxide Data Sources for Neighborhood Estimates of Long-Term Exposure for Health Research.

    Hanigan, Ivan C; Williamson, Grant J; Knibbs, Luke D; Horsley, Joshua; Rolfe, Margaret I; Cope, Martin; Barnett, Adrian G; Cowie, Christine T; Heyworth, Jane S; Serre, Marc L; Jalaludin, Bin; Morgan, Geoffrey G

    2017-11-07

    Exposure to traffic related nitrogen dioxide (NO 2 ) air pollution is associated with adverse health outcomes. Average pollutant concentrations for fixed monitoring sites are often used to estimate exposures for health studies, however these can be imprecise due to difficulty and cost of spatial modeling at the resolution of neighborhoods (e.g., a scale of tens of meters) rather than at a coarse scale (around several kilometers). The objective of this study was to derive improved estimates of neighborhood NO 2 concentrations by blending measurements with modeled predictions in Sydney, Australia (a low pollution environment). We implemented the Bayesian maximum entropy approach to blend data with uncertainty defined using informative priors. We compiled NO 2 data from fixed-site monitors, chemical transport models, and satellite-based land use regression models to estimate neighborhood annual average NO 2 . The spatial model produced a posterior probability density function of estimated annual average concentrations that spanned an order of magnitude from 3 to 35 ppb. Validation using independent data showed improvement, with root mean squared error improvement of 6% compared with the land use regression model and 16% over the chemical transport model. These estimates will be used in studies of health effects and should minimize misclassification bias.

  7. Pooling job physical exposure data from multiple independent studies in a consortium study of carpal tunnel syndrome

    Kapellusch, Jay M.; Garg, Arun; Bao, Stephen S.; Silverstein, Barbara A.; Burt, Susan E.; Dale, Ann Marie; Evanoff, Bradley A.; Gerr, Frederic E.; Harris-Adamson, Carisa; Hegmann, Kurt T.; Merlino, Linda A.; Rempel, David M.

    2015-01-01

    Pooling data from different epidemiological studies of musculoskeletal disorders (MSDs) is necessary to improve statistical power and to more precisely quantify exposure–response relationships for MSDs. The pooling process is difficult and time-consuming, and small methodological differences could lead to different exposure–response relationships. A subcommittee of a six-study research consortium studying carpal tunnel syndrome: (i) visited each study site, (ii) documented methods used to collect physical exposure data and (iii) determined compatibility of exposure variables across studies. Certain measures of force, frequency of exertion and duty cycle were collected by all studies and were largely compatible. A portion of studies had detailed data to investigate simultaneous combinations of force, frequency and duration of exertions. Limited compatibility was found for hand/wrist posture. Only two studies could calculate compatible Strain Index scores, but Threshold Limit Value for Hand Activity Level could be determined for all studies. Challenges of pooling data, resources required and recommendations for future researchers are discussed. PMID:23697792

  8. Residential and service-population exposure to multiple natural hazards in the Mount Hood region of Clackamas County, Oregon

    Mathie, Amy M.; Wood, Nathan

    2013-01-01

    The objective of this research is to document residential and service-population exposure to natural hazards in the rural communities of Clackamas County, Oregon, near Mount Hood. The Mount Hood region of Clackamas County has a long history of natural events that have impacted its small, tourism-based communities. To support preparedness and emergency-management planning in the region, a geospatial analysis of population exposure was used to determine the number and type of residents and service populations in flood-, wildfire-, and volcano-related hazard zones. Service populations are a mix of residents and tourists temporarily benefitting from local services, such as retail, education, or recreation. In this study, service population includes day-use visitors at recreational sites, overnight visitors at hotels and resorts, children at schools, and community-center visitors. Although the heavily-forested, rural landscape suggests few people are in the area, there are seasonal peaks of thousands of visitors to the region. “Intelligent” dasymetric mapping efforts using 30-meter resolution land-cover imagery and U.S. Census Bureau data proved ineffective at adequately capturing either the spatial distribution or magnitude of population at risk. Consequently, an address-point-based hybrid dasymetric methodology of assigning population to the physical location of buildings mapped with a global positioning system was employed. The resulting maps of the population (1) provide more precise spatial distributions for hazard-vulnerability assessments, (2) depict appropriate clustering due to higher density structures, such as apartment complexes and multi-unit commercial buildings, and (3) provide new information on the spatial distribution and temporal variation of people utilizing services within the study area. Estimates of population exposure to flooding, wildfire, and volcanic hazards were determined by using overlay analysis in a geographic information system

  9. An immuno-epidemiological model with threshold delay: a study of the effects of multiple exposures to a pathogen.

    Qesmi, Redouane; Heffernan, Jane M; Wu, Jianhong

    2015-01-01

    An immuno-epidemiological model of pathogen transmission is developed. This model incorporates two main features: (i) the epidemiological model includes within-host pathogen dynamics for an infectious disease, (ii) the susceptible individuals to the infection experience a series of exposures via the pathogen before becoming infectious. It is shown that this model leads naturally to a system of differential delay equations of the threshold type and that these equations can be transformed, in a biologically natural way, to differential equations with state-dependent delay. An interesting dynamical behavior of the model is the bistability phenomena, when the basic reproductive ratio R0 is less than unity, which raises many new challenges to effective infection control.

  10. Digital hologram transformations for RGB color holographic display with independent image magnification and translation in 3D.

    Makowski, Piotr L; Zaperty, Weronika; Kozacki, Tomasz

    2018-01-01

    A new framework for in-plane transformations of digital holograms (DHs) is proposed, which provides improved control over basic geometrical features of holographic images reconstructed optically in full color. The method is based on a Fourier hologram equivalent of the adaptive affine transformation technique [Opt. Express18, 8806 (2010)OPEXFF1094-408710.1364/OE.18.008806]. The solution includes four elementary geometrical transformations that can be performed independently on a full-color 3D image reconstructed from an RGB hologram: (i) transverse magnification; (ii) axial translation with minimized distortion; (iii) transverse translation; and (iv) viewing angle rotation. The independent character of transformations (i) and (ii) constitutes the main result of the work and plays a double role: (1) it simplifies synchronization of color components of the RGB image in the presence of mismatch between capture and display parameters; (2) provides improved control over position and size of the projected image, particularly the axial position, which opens new possibilities for efficient animation of holographic content. The approximate character of the operations (i) and (ii) is examined both analytically and experimentally using an RGB circular holographic display system. Additionally, a complex animation built from a single wide-aperture RGB Fourier hologram is presented to demonstrate full capabilities of the developed toolset.

  11. A low-cost alternative to the optical experiment commercially known as “Magic Hologram – 3D Mirage”

    Osmar Henrique Moura Silva

    2014-09-01

    Full Text Available This work presents a low-cost alternative to the commercialized experiment called “Magic Hologram – Mirage 3D”, which reproduces the real image of an object that is seen three-dimensionally in the air. An analysis of this alternative is carried out, indicating educational aspects of its use in the classroom in quantitative terms.

  12. Evaluation of pulsed laser holograms of flashing sprays by digital image processing and holographic particle image velocimetry

    Feldmann, O.; Gebhard, P.; Mayinger, F.

    1998-01-01

    This study deals with the application of the pulsed laser holography and the digital image processing in the analysis of flashing sprays. Both the information about the macroscopic structures of a spray, such as the breakup-length and the spray-angle, and about its microscopic structures, such as the number, the size, and the location of the generated droplets is stored three-dimensionally on a single pulsed hologram. In addition to that, the velocity of the droplets can be obtained from double pulsed holograms. In every experiment, two holograms are taken, resulting in two three-dimensional reconstructions of the test section, seen from different directions. These reconstructions are scanned by video-cameras with a small depth of field and subdivided into several two-dimensional images. These images are digitized and binarized, and the information about the droplets depicted sharply on each image is saved. In case of a double pulsed hologram, a Fourier-analysis based algorithm creates a search volume to determine the droplets' second position and thus their velocity in each view. A stereo matching modulus correlates both views and determines the position and/or the velocity of each droplet highly accurate. The applicability of the employed holographic technique and the filtering and correlating moduli is proven by the presented results. (author)

  13. Influence of Softening Temperature of Azobenzene Polymers and External Electric Field on Diffraction Efficiency of Polarization Holograms

    Nicolay Davidenko

    2017-12-01

    Full Text Available Growth of the diffraction efficiency and recording velocity was found in the films of copolymers 4-((2- nitrophenyl diazeniylphenylmethacrylate with octylmethacrylate at room temperature holographic recording for copolymer with less softening temperature. Effect of strengthening of the diffraction efficiency was observed when charging surface of the films with recorded hologram in crown discharge.

  14. On artefact-free reconstruction of low-energy (30–250 eV) electron holograms

    Latychevskaia, Tatiana, E-mail: tatiana@physik.uzh.ch; Longchamp, Jean-Nicolas; Escher, Conrad; Fink, Hans-Werner

    2014-10-15

    Low-energy electrons (30–250 eV) have been successfully employed for imaging individual biomolecules. The most simple and elegant design of a low-energy electron microscope for imaging biomolecules is a lensless setup that operates in the holographic mode. In this work we address the problem associated with the reconstruction from the recorded holograms. We discuss the twin image problem intrinsic to inline holography and the problem of the so-called biprism-like effect specific to low-energy electrons. We demonstrate how the presence of the biprism-like effect can be efficiently identified and circumvented. The presented sideband filtering reconstruction method eliminates the twin image and allows for reconstruction despite the biprism-like effect, which we demonstrate on both, simulated and experimental examples. - Highlights: • Radiation damage-free imaging of individual biomolecules. • Elimination of the twin image in inline holograms. • Circumventing biprism-like effect in low-energy electron holograms. • Artefact-free reconstructions of low-energy electron holograms.

  15. On artefact-free reconstruction of low-energy (30–250 eV) electron holograms

    Latychevskaia, Tatiana; Longchamp, Jean-Nicolas; Escher, Conrad; Fink, Hans-Werner

    2014-01-01

    Low-energy electrons (30–250 eV) have been successfully employed for imaging individual biomolecules. The most simple and elegant design of a low-energy electron microscope for imaging biomolecules is a lensless setup that operates in the holographic mode. In this work we address the problem associated with the reconstruction from the recorded holograms. We discuss the twin image problem intrinsic to inline holography and the problem of the so-called biprism-like effect specific to low-energy electrons. We demonstrate how the presence of the biprism-like effect can be efficiently identified and circumvented. The presented sideband filtering reconstruction method eliminates the twin image and allows for reconstruction despite the biprism-like effect, which we demonstrate on both, simulated and experimental examples. - Highlights: • Radiation damage-free imaging of individual biomolecules. • Elimination of the twin image in inline holograms. • Circumventing biprism-like effect in low-energy electron holograms. • Artefact-free reconstructions of low-energy electron holograms

  16. HOLRED - a machine to reproduce and photograph real images from holograms taken in the 15 foot bubble chamber at Fermilab

    Nailor, P.R.

    1985-01-01

    The aim of this paper is to describe the design criteria and philosophy behind a machine to reproject and photograph the real images of neutrino interactions from holograms taken there in the coming run. Detailed analysis of the vertex region of these events will be done from the photographs. (orig./HSI)

  17. Utilization of a liquid crystal spatial light modulator in a gray scale detour phase method for Fourier holograms.

    Makey, Ghaith; El-Daher, Moustafa Sayem; Al-Shufi, Kanj

    2012-11-10

    This paper introduces a new modification for the well-known binary detour phase method, which is largely used to represent Fourier holograms; the modification utilizes gray scale level control provided by a liquid crystal spatial light modulator to improve the traditional binary detour phase. Results are shown by both simulation and experiment.

  18. Multiple assessment methods of prenatal exposure to radio frequency radiation from telecommunication in the Mothers and Children’s Environmental Health (MOCEH study

    Kyung-Hwa Choi

    2016-12-01

    Full Text Available Objectives: To evaluate prenatal exposure to radiofrequency radiation (RFR from telecommunication using a mobile phone questionnaire, operator data logs of mobile phone use and a personal exposure meter (PEM. Material and Methods: The study included 1228 mother–infants pairs from the Mothers and Children’s Environmental Health (MOCEH study – a multicenter prospective cohort study ongoing since 2006, in which participants were enrolled at ≤ 20 weeks of pregnancy, with a follow-up of a child birth and growth to assess the association between prenatal environmental exposure and children’s health. The questionnaire included the average calling frequency per day and the average calling time per day. An EME Spy 100 PEM was used to measure RFR among 269 pregnant women from November 2007 to August 2010. The operators’ log data were obtained from 21 participants. The Spearman’s correlation test was performed to evaluate correlation coefficient and 95% confidence intervals between the mobile phone use information from the questionnaire, operators’ log data, and data recorded by the PEM. Results: The operators’ log data and information from the self-reported questionnaire showed significantly high correlations in the average calling frequency per day (ρ = 0.6, p = 0.004 and average calling time per day (ρ = 0.5, p = 0.02. The correlation between information on the mobile phone use in the self-reported questionnaire and exposure index recorded by the PEM was poor. But correlation between the information of the operators’ log data and exposure index for transmission of mobile communication was significantly high: correlation coefficient (p-value was 0.44 (0.07 for calling frequency per day, and it was 0.49 (0.04 for calling time per day. Conclusions: The questionnaire information on the mobile phone use showed moderate to high quality. Using multiple methods for exposure assessment might be better than using only one method. Int J Occup

  19. Body temperature is elevated and linked to fatigue in relapsing-remitting multiple sclerosis, even without heat exposure.

    Sumowski, James F; Leavitt, Victoria M

    2014-07-01

    To investigate whether (1) resting body temperature is elevated in patients with relapsing-remitting multiple sclerosis (RRMS) relative to healthy individuals and patients with secondary progressive multiple sclerosis (SPMS), and (2) warmer body temperature is linked to worse fatigue in patients with RRMS. Cross-sectional study. Climate-controlled laboratory (∼22°C) within a nonprofit medical rehabilitation research center. Patients with RRMS (n=50), matched healthy controls (n=40), and patients with SPMS (n=22). Not applicable. Body temperature was measured with an aural infrared thermometer (normative body temperature for this thermometer, 36.75°C), and differences were compared across patients with RRMS and SPMS and healthy persons. Patients with RRMS completed measures of general fatigue (Fatigue Severity Scale [FSS]), as well as physical and cognitive fatigue (Modified Fatigue Impact Scale [MFIS]). There was a large effect of group (Pphysical fatigue (physical fatigue subscale of the MFIS; rp=.318, P=.026), but not cognitive fatigue (cognitive fatigue subscale of the MIFS; rp=-.017, P=.909). These are the first-ever demonstrations that body temperature is elevated endogenously in patients with RRMS and linked to worse fatigue. We discuss these findings in the context of failed treatments for fatigue in RRMS, including several failed randomized controlled trials (RCTs) of stimulants (modafinil). In contrast, our findings may help explain how RCTs of cooling garments and antipyretics (aspirin) have effectively reduced MS fatigue, and encourage further research on cooling/antipyretic treatments of fatigue in RRMS. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  20. Encryption and display of multiple-image information using computer-generated holography with modified GS iterative algorithm

    Xiao, Dan; Li, Xiaowei; Liu, Su-Juan; Wang, Qiong-Hua

    2018-03-01

    In this paper, a new scheme of multiple-image encryption and display based on computer-generated holography (CGH) and maximum length cellular automata (MLCA) is presented. With the scheme, the computer-generated hologram, which has the information of the three primitive images, is generated by modified Gerchberg-Saxton (GS) iterative algorithm using three different fractional orders in fractional Fourier domain firstly. Then the hologram is encrypted using MLCA mask. The ciphertext can be decrypted combined with the fractional orders and the rules of MLCA. Numerical simulations and experimental display results have been carried out to verify the validity and feasibility of the proposed scheme.

  1. A randomized male tolerance study of dapivirine gel following multiple topical penile exposures (MTN 012/IPM 010).

    Cranston, Ross D; Hoesley, Craig; Carballo-Diéguez, Alex; Hendrix, Craig W; Husnik, Marla; Levy, Lisa; Hall, Wayne; Soto-Torres, Lydia; Nel, Annalene M

    2014-02-01

    Dapivirine (DPV) is a nonnucleoside reverse transcriptase inhibitor with a favorable safety profile following vaginal application. A penile tolerance study was conducted prior to further development of DPV as a candidate vaginal microbicide. Twenty-four circumcised and 24 uncircumcised (N=48) healthy HIV-negative male participants aged 18 years or older were randomized 2:1:1 to apply DPV 0.05% gel, matched placebo gel, or universal placebo gel, respectively, to their penis once daily for 7 sequential days. The safety, acceptability, and pharmacokinetic profile of DPV 0.05% gel were assessed by the presence of Grade 2 or higher genitourinary adverse events (AEs) and systemic AEs, a behavioral questionnaire, and pharmacokinetic plasma blood draw, respectively, at the final clinic visit (FCV). There were no Grade 2 genitourinary AEs in 47 participants completing the FCV. One participant in the DPV arm failed to attend the FCV. There were 13 AEs reported; all were Grade 1 except one Grade 2 corneal laceration unrelated to study product. Participants liked the gel to a moderate extent, yet 72% reported they would be "very likely" to use a gel like the one they used in the study every time they have intercourse. DPV was detectable in plasma in all 23 DPV arm study participants at the FCV. On average, the circumcised participants' DPV concentrations were 54% of those in uncircumcised participants (p=0.07). Topical seven-day penile application of DPV 0.05% gel was locally and systemically safe, was acceptable to male participants, and resulted in systemic exposure to the drug.

  2. An Integrated Modeling Framework Forecasting Ecosystem Exposure-- A Systems Approach to the Cumulative Impacts of Multiple Stressors

    Johnston, J. M.

    2013-12-01

    Freshwater habitats provide fishable, swimmable and drinkable resources and are a nexus of geophysical and biological processes. These processes in turn influence the persistence and sustainability of populations, communities and ecosystems. Climate change and landuse change encompass numerous stressors of potential exposure, including the introduction of toxic contaminants, invasive species, and disease in addition to physical drivers such as temperature and hydrologic regime. A systems approach that includes the scientific and technologic basis of assessing the health of ecosystems is needed to effectively protect human health and the environment. The Integrated Environmental Modeling Framework 'iemWatersheds' has been developed as a consistent and coherent means of forecasting the cumulative impact of co-occurring stressors. The Framework consists of three facilitating technologies: Data for Environmental Modeling (D4EM) that automates the collection and standardization of input data; the Framework for Risk Assessment of Multimedia Environmental Systems (FRAMES) that manages the flow of information between linked models; and the Supercomputer for Model Uncertainty and Sensitivity Evaluation (SuperMUSE) that provides post-processing and analysis of model outputs, including uncertainty and sensitivity analysis. Five models are linked within the Framework to provide multimedia simulation capabilities for hydrology and water quality processes: the Soil Water Assessment Tool (SWAT) predicts surface water and sediment runoff and associated contaminants; the Watershed Mercury Model (WMM) predicts mercury runoff and loading to streams; the Water quality Analysis and Simulation Program (WASP) predicts water quality within the stream channel; the Habitat Suitability Index (HSI) model scores physicochemical habitat quality for individual fish species; and the Bioaccumulation and Aquatic System Simulator (BASS) predicts fish growth, population dynamics and bioaccumulation

  3. Evidence that bisphenol A (BPA) can be accurately measured without contamination in human serum and urine, and that BPA causes numerous hazards from multiple routes of exposure

    vom Saal, Frederick S.; Welshons, Wade V.

    2016-01-01

    There is extensive evidence that bisphenol A (BPA) is related to a wide range of adverse health effects based on both human and experimental animal studies. However, a number of regulatory agencies have ignored all hazard findings. Reports of high levels of unconjugated (bioactive) serum BPA in dozens of human biomonitoring studies have also been rejected based on the prediction that the findings are due to assay contamination and that virtually all ingested BPA is rapidly converted to inactive metabolites. NIH and industry-sponsored round robin studies have demonstrated that serum BPA can be accurately assayed without contamination, while the FDA lab has acknowledged uncontrolled assay contamination. In reviewing the published BPA biomonitoring data, we find that assay contamination is, in fact, well controlled in most labs, and cannot be used as the basis for discounting evidence that significant and virtually continuous exposure to BPA must be occurring from multiple sources. PMID:25304273

  4. Three-dimensional imaging using computer-generated holograms synthesized from 3-D Fourier spectra

    Yatagai, Toyohiko; Miura, Ken-ichi; Sando, Yusuke; Itoh, Masahide

    2008-01-01

    Computer-generated holograms(CGHs) synthesized from projection images of real existing objects are considered. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD. According to the principles of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel CGH is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary. Moreover, when a color CCD is used in recording, it is easily possible to record and reconstruct colorful objects. Finally, we demonstrate reconstruction of biological objects.

  5. High collimated coherent illumination for reconstruction of digitally calculated holograms: design and experimental realization

    Morozov, Alexander; Dubinin, German; Dubynin, Sergey; Yanusik, Igor; Kim, Sun Il; Choi, Chil-Sung; Song, Hoon; Lee, Hong-Seok; Putilin, Andrey; Kopenkin, Sergey; Borodin, Yuriy

    2017-06-01

    Future commercialization of glasses-free holographic real 3D displays requires not only appropriate image quality but also slim design of backlight unit and whole display device to match market needs. While a lot of research aimed to solve computational issues of forming Computer Generated Holograms for 3D Holographic displays, less focus on development of backlight units suitable for 3D holographic display applications with form-factor of conventional 2D display systems. Thereby, we report coherent backlight unit for 3D holographic display with thickness comparable to commercially available 2D displays (cell phones, tablets, laptops, etc.). Coherent backlight unit forms uniform, high-collimated and effective illumination of spatial light modulator. Realization of such backlight unit is possible due to holographic optical elements, based on volume gratings, constructing coherent collimated beam to illuminate display plane. Design, recording and measurement of 5.5 inch coherent backlight unit based on two holographic optical elements are presented in this paper.

  6. Optimal design of tilt carrier frequency computer-generated holograms to measure aspherics.

    Peng, Jiantao; Chen, Zhe; Zhang, Xingxiang; Fu, Tianjiao; Ren, Jianyue

    2015-08-20

    Computer-generated holograms (CGHs) provide an approach to high-precision metrology of aspherics. A CGH is designed under the trade-off among size, mapping distortion, and line spacing. This paper describes an optimal design method based on the parametric model for tilt carrier frequency CGHs placed outside the interferometer focus points. Under the condition of retaining an admissible size and a tolerable mapping distortion, the optimal design method has two advantages: (1) separating the parasitic diffraction orders to improve the contrast of the interferograms and (2) achieving the largest line spacing to minimize sensitivity to fabrication errors. This optimal design method is applicable to common concave aspherical surfaces and illustrated with CGH design examples.

  7. Three-dimensional scene encryption and display based on computer-generated holograms.

    Kong, Dezhao; Cao, Liangcai; Jin, Guofan; Javidi, Bahram

    2016-10-10

    An optical encryption and display method for a three-dimensional (3D) scene is proposed based on computer-generated holograms (CGHs) using a single phase-only spatial light modulator. The 3D scene is encoded as one complex Fourier CGH. The Fourier CGH is then decomposed into two phase-only CGHs with random distributions by the vector stochastic decomposition algorithm. Two CGHs are interleaved as one final phase-only CGH for optical encryption and reconstruction. The proposed method can support high-level nonlinear optical 3D scene security and complex amplitude modulation of the optical field. The exclusive phase key offers strong resistances of decryption attacks. Experimental results demonstrate the validity of the novel method.

  8. Three-dimensional imaging using computer-generated holograms synthesized from 3-D Fourier spectra

    Yatagai, Toyohiko; Miura, Ken-ichi; Sando, Yusuke; Itoh, Masahide [University of Tsukba, Institute of Applied Physics, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan)], E-mail: yatagai@cc.utsunomiya-u.ac.jp

    2008-11-01

    Computer-generated holograms(CGHs) synthesized from projection images of real existing objects are considered. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD. According to the principles of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel CGH is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary. Moreover, when a color CCD is used in recording, it is easily possible to record and reconstruct colorful objects. Finally, we demonstrate reconstruction of biological objects.

  9. Wavelet-based tracking of bacteria in unreconstructed off-axis holograms.

    Marin, Zach; Wallace, J Kent; Nadeau, Jay; Khalil, Andre

    2018-03-01

    We propose an automated wavelet-based method of tracking particles in unreconstructed off-axis holograms to provide rough estimates of the presence of motion and particle trajectories in digital holographic microscopy (DHM) time series. The wavelet transform modulus maxima segmentation method is adapted and tailored to extract Airy-like diffraction disks, which represent bacteria, from DHM time series. In this exploratory analysis, the method shows potential for estimating bacterial tracks in low-particle-density time series, based on a preliminary analysis of both living and dead Serratia marcescens, and for rapidly providing a single-bit answer to whether a sample chamber contains living or dead microbes or is empty. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Visible-Frequency Dielectric Metasurfaces for Multiwavelength Achromatic and Highly Dispersive Holograms.

    Wang, Bo; Dong, Fengliang; Li, Qi-Tong; Yang, Dong; Sun, Chengwei; Chen, Jianjun; Song, Zhiwei; Xu, Lihua; Chu, Weiguo; Xiao, Yun-Feng; Gong, Qihuang; Li, Yan

    2016-08-10

    Dielectric metasurfaces built up with nanostructures of high refractive index represent a powerful platform for highly efficient flat optical devices due to their easy-tuning electromagnetic scattering properties and relatively high transmission efficiencies. Here we show visible-frequency silicon metasurfaces formed by three kinds of nanoblocks multiplexed in a subwavelength unit to constitute a metamolecule, which are capable of wavefront manipulation for red, green, and blue light simultaneously. Full phase control is achieved for each wavelength by independently changing the in-plane orientations of the corresponding nanoblocks to induce the required geometric phases. Achromatic and highly dispersive meta-holograms are fabricated to demonstrate the wavefront manipulation with high resolution. This technique could be viable for various practical holographic applications and flat achromatic devices.

  11. Improved look-up table method of computer-generated holograms.

    Wei, Hui; Gong, Guanghong; Li, Ni

    2016-11-10

    Heavy computation load and vast memory requirements are major bottlenecks of computer-generated holograms (CGHs), which are promising and challenging in three-dimensional displays. To solve these problems, an improved look-up table (LUT) method suitable for arbitrarily sampled object points is proposed and implemented on a graphics processing unit (GPU) whose reconstructed object quality is consistent with that of the coherent ray-trace (CRT) method. The concept of distance factor is defined, and the distance factors are pre-computed off-line and stored in a look-up table. The results show that while reconstruction quality close to that of the CRT method is obtained, the on-line computation time is dramatically reduced compared with the LUT method on the GPU and the memory usage is lower than that of the novel-LUT considerably. Optical experiments are carried out to validate the effectiveness of the proposed method.

  12. Fast calculation method of computer-generated hologram using a depth camera with point cloud gridding

    Zhao, Yu; Shi, Chen-Xiao; Kwon, Ki-Chul; Piao, Yan-Ling; Piao, Mei-Lan; Kim, Nam

    2018-03-01

    We propose a fast calculation method for a computer-generated hologram (CGH) of real objects that uses a point cloud gridding method. The depth information of the scene is acquired using a depth camera and the point cloud model is reconstructed virtually. Because each point of the point cloud is distributed precisely to the exact coordinates of each layer, each point of the point cloud can be classified into grids according to its depth. A diffraction calculation is performed on the grids using a fast Fourier transform (FFT) to obtain a CGH. The computational complexity is reduced dramatically in comparison with conventional methods. The feasibility of the proposed method was confirmed by numerical and optical experiments.

  13. Encoding plaintext by Fourier transform hologram in double random phase encoding using fingerprint keys

    Takeda, Masafumi; Nakano, Kazuya; Suzuki, Hiroyuki; Yamaguchi, Masahiro

    2012-09-01

    It has been shown that biometric information can be used as a cipher key for binary data encryption by applying double random phase encoding. In such methods, binary data are encoded in a bit pattern image, and the decrypted image becomes a plain image when the key is genuine; otherwise, decrypted images become random images. In some cases, images decrypted by imposters may not be fully random, such that the blurred bit pattern can be partially observed. In this paper, we propose a novel bit coding method based on a Fourier transform hologram, which makes images decrypted by imposters more random. Computer experiments confirm that the method increases the randomness of images decrypted by imposters while keeping the false rejection rate as low as in the conventional method.

  14. Encoding plaintext by Fourier transform hologram in double random phase encoding using fingerprint keys

    Takeda, Masafumi; Nakano, Kazuya; Suzuki, Hiroyuki; Yamaguchi, Masahiro

    2012-01-01

    It has been shown that biometric information can be used as a cipher key for binary data encryption by applying double random phase encoding. In such methods, binary data are encoded in a bit pattern image, and the decrypted image becomes a plain image when the key is genuine; otherwise, decrypted images become random images. In some cases, images decrypted by imposters may not be fully random, such that the blurred bit pattern can be partially observed. In this paper, we propose a novel bit coding method based on a Fourier transform hologram, which makes images decrypted by imposters more random. Computer experiments confirm that the method increases the randomness of images decrypted by imposters while keeping the false rejection rate as low as in the conventional method. (paper)

  15. Digital holography super-resolution for accurate three-dimensional reconstruction of particle holograms.

    Verrier, Nicolas; Fournier, Corinne

    2015-01-15

    In-line digital holography (DH) is used in many fields to locate and size micro or nano-objects spread in a volume. To reconstruct simple shaped objects, the optimal approach is to fit an imaging model to accurately estimate their position and their characteristic parameters. Increasing the accuracy of the reconstruction is a big issue in DH, particularly when the pixel is large or the signal-to-noise ratio is low. We suggest exploiting the information redundancy of videos to improve the reconstruction of the holograms by jointly estimating the position of the objects and the characteristic parameters. Using synthetic and experimental data, we checked experimentally that this approach can improve the accuracy of the reconstruction by a factor more than the square root of the image number.

  16. Estimation of lung tissue doses following exposure to low-LET radiation in the Canadian study of cancer following multiple fluoroscopies

    Howe, G.R.; Yaffe, M.

    1992-02-01

    Lung tissue doses from exposure to external low-LET radiation have been estimated for each year between 1930 and 1960 for 92,707 tuberculosis patients first treated in Canadian institutions between 1930 and 1952. Many of these patients received multiple chest fluoroscopies together with treatment by artificial pneumothorax, and thus accumulated doses up to 15.7 grays. The estimated doses have been used in a statistical analysis of lung cancer mortality between 1950 and 1987 occurring among 64,698 patients known to be alive at the start of 1950, and followed by linkage to the Canadian national mortality data base. There were substantial variations in the total cumulative lung tissue dose received by the cohort, with 2,490 individuals having doses in excess of 1.7 grays. A total of 1,156 lung cancer deaths was observed in the cohort, and these have been used to estimate relative risks. The most appropriate risk model appears to be a simple linear relative risk function, with an excess relative risk coefficient of 0.089 for an absorbed dose of 1 gray. This contrasts with estimates of relative risk based on the atomic bomb survivors study, for which the excess relative risk coefficient for males 20 years after the first exposure is estimated to be 0.64. The difference is statistically significant. It is postulated that fractionation and dose rate effectiveness factors may account for some of the discrepancy. (Modified author abstract) (14 refs., 20 tabs.)

  17. Sunscreens with broad-spectrum absorption decrease the trans TO cis photoisomerization of urocanic acid in the human stratum corneum after multiple UV light exposures

    Krien, P.M.; Moyal, D.

    1994-01-01

    The trans to cis photoisomerization of urocanic acid (UCA) in skin is considered to play an important role in the mechanism of immunosuppression. We have investigated the effects of skin type and various sunscreens with low sun protection factor (SPF) on the UV-induced cis-UCA formation in human skin after exposure to artificial UV light. The rate of cis-UCA formation depends little on the skin type and is reduced by topical application of sunscreens. The rate of cis-UCA formation decreases with increasing SPF and only broad-spectrum, highly protective sunscreens offer protection against the UV-induced formation of cis-UCA, which accumulates in the stratum corneum after multiple UV exposures. A theoretical approach to estimate the distribution of cis-UCA after irradiation indicates that this compound may diffuse into the deeper layers of the epidermis with D ∼ 10 -17 m 2 /s, and that its elimination from the stratum corneum is mainly due to desquamation. (author)

  18. Prenatal exposure to multiple pesticides is associated with auditory brainstem response at 9months in a cohort study of Chinese infants.

    Sturza, Julie; Silver, Monica K; Xu, Lin; Li, Mingyan; Mai, Xiaoqin; Xia, Yankai; Shao, Jie; Lozoff, Betsy; Meeker, John

    2016-01-01

    exposure on ABR latency delay, suggesting an additive or multiplicative effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Body temperature is elevated and linked to fatigue in relapsing-remitting multiple sclerosis, even without heat exposure

    Sumowski, James F.; Leavitt, Victoria M.

    2014-01-01

    Objective To investigate whether resting body temperature is elevated and linked to fatigue in patients with relapsing-remitting multiple sclerosis (RRMS). Design Cross-sectional study investigating (a) differences in resting body temperature across RRMS, SPMS, and healthy groups, and (b) the relationship between body temperature and fatigue in RRMS patients. Setting Climate-controlled laboratory (~22°C) within a non-profit medical rehabilitation research center. Participants Fifty patients with RRMS, 40 matched healthy controls, and 22 patients with secondary-progressive MS (SPMS). Intervention None. Main Outcome Measure(s) Body temperature was measured with an aural infrared thermometer (normal body temperature for this thermometer is 36.75°C), and differences were compared across RRMS, SPMS, and healthy persons. RRMS patients completed measures of general fatigue (Fatigue Severity Scale; FSS), as well as physical and cognitive fatigue (Modified Fatigue Impact Scale; MFIS). Results There was a large effect of group (ptemperature was higher in RRMS patients (37.04°C±0.27) relative to healthy controls (36.83 ± 0.33; p = .009) and SPMS patients (36.75°C±0.39; p=.001). Warmer body temperature in RRMS patients was associated with worse general fatigue (FSS; rp=.315, p=.028) and physical fatigue (pMFIS; rp=.318, p=.026), but not cognitive fatigue (cMIFS; rp=−.017, p=.909). Conclusions These are the first-ever demonstrations that body temperature is elevated endogenously in RRMS patients, and linked to worse fatigue. We discuss these findings in the context of failed treatments for fatigue in RRMS, including several failed randomized controlled trials (RCTs) of stimulants (modafinil). In contrast, our findings may help explain how RCTs of cooling garments and antipyretics (aspirin) have effectively reduced MS fatigue, and encourage further research on cooling/antipyretic treatments of fatigue in RRMS. PMID:24561056

  20. Adaption of the microbial community to continuous exposures of multiple residual antibiotics in sediments from a salt-water aquacultural farm.

    Xi, Xiuping; Wang, Min; Chen, Yongshan; Yu, Shen; Hong, Youwei; Ma, Jun; Wu, Qian; Lin, Qiaoyin; Xu, Xiangrong

    2015-06-15

    Residual antibiotics from aquacultural farming may alter microbial community structure in aquatic environments in ways that may adversely or positively impact microbially-mediated ecological functions. This study investigated 26 ponds (26 composited samples) used to produce fish, razor clam and shrimp (farming and drying) and 2 channels (10 samples) in a saltwater aquacultural farm in southern China to characterize microbial community structure (represented by phospholipid fatty acids) in surface sediments (0-10 cm) with long-term exposure to residual antibiotics. 11 out of 14 widely-used antibiotics were quantifiable at μg kg(-1) levels in sediments but their concentrations did not statistically differ among ponds and channels, except norfloxacin in drying shrimp ponds and thiamphenicol in razor clam ponds. Concentrations of protozoan PLFAs were significantly increased in sediments from razor clam ponds while other microbial groups were similar among ponds and channels. Both canonical-correlation and stepwise-multiple-regression analyses on microbial community and residual antibiotics suggested that roxithromycin residuals were significantly related to shifts in microbial community structure in sediments. This study provided field evidence that multiple residual antibiotics at low environmental levels from aquacultural farming do not produce fundamental shifts in microbial community structure. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Enhanced optical power of GaN-based light-emitting diode with compound photonic crystals by multiple-exposure nanosphere-lens lithography

    Zhang, Yonghui; Wei, Tongbo, E-mail: tbwei@semi.ac.cn; Xiong, Zhuo; Shang, Liang; Tian, Yingdong; Zhao, Yun; Zhou, Pengyu; Wang, Junxi; Li, Jinmin [Semiconductor Lighting Technology Research and Development Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2014-07-07

    The light-emitting diodes (LEDs) with single, twin, triple, and quadruple photonic crystals (PCs) on p-GaN are fabricated by multiple-exposure nanosphere-lens lithography (MENLL) process utilizing the focusing behavior of polystyrene spheres. Such a technique is easy and economical for use in fabricating compound nano-patterns. The optimized tilted angle is decided to be 26.6° through mathematic calculation to try to avoid the overlay of patterns. The results of scanning electron microscopy and simulations reveal that the pattern produced by MENLL is a combination of multiple ovals. Compared to planar-LED, the light output power of LEDs with single, twin, triple, and quadruple PCs is increased by 14.78%, 36.03%, 53.68%, and 44.85% under a drive current 350 mA, respectively. Furthermore, all PC-structures result in no degradation of the electrical properties. The stimulated results indicate that the highest light extraction efficiency of LED with the clover-shape triple PC is due to the largest scattering effect on propagation of light from GaN into air.

  2. The Impact of Multiple Concussions on Emotional Distress, Post-Concussive Symptoms, and Neurocognitive Functioning in Active Duty United States Marines Independent of Combat Exposure or Emotional Distress

    Lathan, Corinna E.; Bleiberg, Joseph; Tsao, Jack W.

    2014-01-01

    Abstract Controversy exists as to whether the lingering effects of concussion on emotional, physical, and cognitive symptoms is because of the effects of brain trauma or purely to emotional factors such as post-traumatic stress disorder or depression. This study examines the independent effects of concussion on persistent symptoms. The Defense Automated Neurobehavioral Assessment, a clinical decision support tool, was used to assess neurobehavioral functioning in 646 United States Marines, all of whom were fit for duty. Marines were assessed for concussion history, post-concussive symptoms, emotional distress, neurocognitive functioning, and deployment history. Results showed that a recent concussion or ever having experienced a concussion was associated with an increase in emotional distress, but not with persistent post-concussive symptoms (PPCS) or neurocognitive functioning. Having had multiple lifetime concussions, however, was associated with greater emotional distress, PPCS, and reduced neurocognitive functioning that needs attention and rapid discrimination, but not for memory-based tasks. These results are independent of deployment history, combat exposure, and symptoms of post-traumatic stress disorder and depression. Results supported earlier findings that a previous concussion is not generally associated with post-concussive symptoms independent of covariates. In contrast with other studies that failed to find a unique contribution for concussion to PPCS, however, evidence of recent and multiple concussion was seen across a range of emotional distress, post-concussive symptoms, and neurocognitive functioning in this study population. Results are discussed in terms of implications for assessing concussion on return from combat. PMID:25003552

  3. Glyphosate epidemiology expert panel review: a weight of evidence systematic review of the relationship between glyphosate exposure and non-Hodgkin's lymphoma or multiple myeloma.

    Acquavella, John; Garabrant, David; Marsh, Gary; Sorahan, Tom; Weed, Douglas L

    2016-09-01

    We conducted a systematic review of the epidemiologic literature for glyphosate focusing on non-Hodgkin's lymphoma (NHL) and multiple myeloma (MM) - two cancers that were the focus of a recent review by an International Agency for Research on Cancer Working Group. Our approach was consistent with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews. We evaluated each relevant study according to a priori criteria for study quality: adequacy of study size, likelihood of confounding, potential for other biases and adequacy of the statistical analyses. Our evaluation included seven unique studies for NHL and four for MM, all but one of which were case control studies for each cancer. For NHL, the case-control studies were all limited by the potential for recall bias and the lack of adequate multivariate adjustment for multiple pesticide and other farming exposures. Only the Agricultural Health (cohort) Study met our a priori quality standards and this study found no evidence of an association between glyphosate and NHL. For MM, the case control studies shared the same limitations as noted for the NHL case-control studies and, in aggregate, the data were too sparse to enable an informed causal judgment. Overall, our review did not find support in the epidemiologic literature for a causal association between glyphosate and NHL or MM.

  4. Micro-Holograms in a Methyl Red-Doped Polymer-Dispersed Liquid Crystal (E48:PVP

    N. P. Hermosa II

    2003-06-01

    Full Text Available Feasibility of a holographic point-by-point storage in a methyl red-doped Polymer-Dispersed LiquidCrystal (PDLC is determined. Micro-holograms (gratings are recorded next to each other. Smallestgrating diameter obtained is 69.9 mm, with minimum grating distance of 80 mm. Recording of adjacentgrating reduces the diffraction efficiency of existing grating by 17% (average.

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

    Linck, Martin, E-mail: linck@ceos-gmbh.de [CEOS GmbH, Englerstr. 28, D-69126 Heidelberg (Germany)

    2013-01-15

    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: Black-Right-Pointing-Pointer Optimized aberration parameters for high-resolution off-axis holography. Black-Right-Pointing-Pointer Simulation and analysis of noise in high-resolution off-axis holograms. Black-Right-Pointing-Pointer Improving signal resolution in the holographically reconstructed phase shift. Black-Right-Pointing-Pointer Comparison of &apos

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

    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.

  7. Effect of the Power Balance® hologram on balance, flexibility, strength and speed-coordination among university students

    Rafael Merino Marban, Daniel Mayorga Vega, Emilio Fernández Rodríguez, Francisco José Santana Pérez, Oscar Romero Ramos

    2011-01-01

    Full Text Available Based on the body’s energy field, the inventors of Power Balance® have created a hologram that theoretically runs through frequencies that are in our natural environment. Its creators say that people may experience improve balance, strength, flexibility, endurance, concentration, coordination and recovery time, among others. The purpose of this research is to evaluate the effect of Power Balance® hologram on balance, flexibility, strength and speed-coordination in university students. A sample of 105 young volunteers’ physical education students (age 20.91 ± 3.36 years, mass 69.69 ± 11.35 kg, height 171.70 ± 8.07 cm was used. A between-group experimental design with double-blind control group was used to evaluate the possible effects of the Power Balance ® on the dynamic balance, flexibility, abdominal strength, endurance and speed-coordination measured with the Dynamic Balance Test, Sit and Reach, Sit-ups in 30 seconds and Race 10 x 5 m, respectively. A t of Student for independent and dependent samples was used to assess the potential effects between-group and intra-group, respectively. Power Balance®’s hologram produces no significant effects on the balance, flexibility, strength and speed-coordination among university students

  8. Far-field and Fresnel Liquid Crystal Geometric Phase Holograms via Direct-Write Photo-Alignment

    Xiao Xiang

    2017-12-01

    Full Text Available We study computer-generated geometric-phase holograms (GPHs realized by photo-aligned liquid crystals, in both simulation and experiment. We demonstrate both far-field and Fresnel holograms capable of producing far-field and near-field images with preserved fidelity for all wavelengths. The GPHs are fabricated by patterning a photo-alignment layer (PAL using a direct-write laser scanner and coating the surface with a polymerizable liquid crystal (i.e., a reactive mesogen. We study various recording pixel sizes, down to 3 μm, that are easily recorded in the PAL. We characterize the fabricated elements and find good agreement with theory and numerical simulation. Because of the wavelength independent geometric phase, the (phase fidelity of the replay images is preserved for all wavelengths, unlike conventional dynamic phase holograms. However, governed by the diffraction equation, the size and location of a reconstructed image depends on the replay wavelength for far-field and near-field GPHs, respectively. These offer interesting opportunities for white-light holography.

  9. Morphological abnormalities of embryonic cranial nerves after in utero exposure to valproic acid: implications for the pathogenesis of autism with multiple developmental anomalies.

    Tashiro, Yasura; Oyabu, Akiko; Imura, Yoshio; Uchida, Atsuko; Narita, Naoko; Narita, Masaaki

    2011-06-01

    Autism is often associated with multiple developmental anomalies including asymmetric facial palsy. In order to establish the etiology of autism with facial palsy, research into developmental abnormalities of the peripheral facial nerves is necessary. In the present study, to investigate the development of peripheral cranial nerves for use in an animal model of autism, rat embryos were treated with valproic acid (VPA) in utero and their cranial nerves were visualized by immunostaining. Treatment with VPA after embryonic day 9 had a significant effect on the peripheral fibers of several cranial nerves. Following VPA treatment, immunoreactivity within the trigeminal, facial, glossopharyngeal and vagus nerves was significantly reduced. Additionally, abnormal axonal pathways were observed in the peripheral facial nerves. Thus, the morphology of several cranial nerves, including the facial nerve, can be affected by prenatal VPA exposure as early as E13. Our findings indicate that disruption of early facial nerve development is involved in the etiology of asymmetric facial palsy, and may suggest a link to the etiology of autism. Copyright © 2011 ISDN. Published by Elsevier Ltd. All rights reserved.

  10. Effect of recording condition on the diffraction efficiency of magnetic hologram with magnetic garnet films

    Nakamura, Yuichi, E-mail: nakamura@ee.tut.ac.jp; Takagi, Hiroyuki; Lim, Pang Boey; Inoue, Mitsuteru [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1 Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2014-09-14

    A holographic memory has been attracting attention as recording media with high recording density and high data transfer rate. We have studied the magnetic garnets as a rewritable and long life media for magnetic holography. However, since the signal intensity of reconstructed image was relatively low, the effects of recording conditions on the diffraction efficiency of magnetic hologram were investigated with experiments and the numerical simulation using COMSOL multi-physics. The diffraction efficiency tends to decrease as increasing the spatial frequency, and the use of short pulse laser with the pulse width of 50 ps was found to be effective to achieve high diffraction efficiency. This suggests that the formation of clear magnetic fringe similar to interference pattern can be obtained by the use of short pulse laser since undesirable heat diffusion during radiation does not occur. On the other hand, the diffraction efficiency increased as increasing the film thickness up to 3.1 μm but was saturated in the garnet film thicker than 3.1 μm in the case of spatial frequency of 1500 line pair/mm. The numerical simulation showed that the effective depth of magnetic fringe was limited about 1.8 μm irrespective of the garnet film thickness because the fringes were connected by thermal diffusion near the surface of the film, and the effective depth is limited due to this connection of the magnetic fringe. Avoiding this fringe connection, much higher diffraction efficiency will be achieved.

  11. Exploring the threshold of perception and reverie for a display hologram

    Dawson, Paula H.

    1996-03-01

    The subjects of display holograms tend to fall into 3 categories--those which aspire to replicate their real world counterparts, those which through the conventions of graphics, text or diagrams represent abstract information and those which record holographic phenomena of subjects. In designing a holographic shrine for a Catholic Church in Australia the modes of representation available through the history of art and their bearing on holographic image types were examined. The most highly symbolic elements of the image were recorded by interferometric techniques in order that they appeared to be made only from light and darkness. To enable the viewer to make a transition from perception to reverie it was necessary for the scale of the image to encourage z axis eye movement. This experiences of staring into space, was achieved by leading attention from near to far ground objects along the omnidirectional segments of a highly embellished geodesic dome. Links between near and far ground objects were made through the use of darkness, in particular by the intentional overexposure of several hundred live flowers which form part of the dome texture. The combination of replication of material objects and holographic phenomena produce a non literal conjunction which stimulates a contemplative response in the viewer.

  12. Prospects for quantitative and time-resolved double and continuous exposure off-axis electron holography

    Migunov, Vadim, E-mail: v.migunov@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Dwyer, Christian [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Department of Physics, Arizona State University, Tempe, AZ 85287 (United States); Boothroyd, Chris B. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Pozzi, Giulio [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Department of Physics and Astronomy, University of Bologna, viale B. Pichat 6/2, Bologna 40127 (Italy); Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2017-07-15

    The technique of double exposure electron holography, which is based on the superposition of two off-axis electron holograms, was originally introduced before the availability of digital image processing to allow differences between electron-optical phases encoded in two electron holograms to be visualised directly without the need for holographic reconstruction. Here, we review the original method and show how it can now be extended to permit quantitative studies of phase shifts that oscillate in time. We begin with a description of the theory of off-axis electron hologram formation for a time-dependent electron wave that results from the excitation of a specimen using an external stimulus with a square, sinusoidal, triangular or other temporal dependence. We refer to the more general method as continuous exposure electron holography, present preliminary experimental measurements and discuss how the technique can be used to image electrostatic potentials and magnetic fields during high frequency switching experiments. - Highlights: • Double and continuous exposure electron holography are described in detail. • The ability to perform quantitative studies of phase shifts that are oscillating in time is illustrated. • Theoretical considerations related to noise are presented. • Future high frequency electromagnetic switching experiments are proposed.

  13. Available number of multiplexed holograms based on signal-to-noise ratio analysis in reflection-type holographic memory using three-dimensional speckle-shift multiplexing.

    Nishizaki, Tatsuya; Matoba, Osamu; Nitta, Kouichi

    2014-09-01

    The recording properties of three-dimensional speckle-shift multiplexing in reflection-type holographic memory are analyzed numerically. Three-dimensional recording can increase the number of multiplexed holograms by suppressing the cross-talk noise from adjacent holograms by using depth-direction multiplexing rather than in-plane multiplexing. Numerical results indicate that the number of multiplexed holograms in three-layer recording can be increased by 1.44 times as large as that of a single-layer recording when an acceptable signal-to-noise ratio is set to be 2 when NA=0.43 and the thickness of the recording medium is 0.5 mm.

  14. Risk factors for asthma and timing of exposure among first generation Arab immigrants: a pilot effort to elucidate the role of exposure to risk factors over multiple life stages

    Considerable controversy exists over the role of aero-allergens in asthma etiology. Some studies show increased risk with microbe and allergen exposure, while others show decreased risk. These discrepancies may be explained by timing of exposure. Previous research suggests that e...

  15. Ultrafast layer based computer-generated hologram calculation with sparse template holographic fringe pattern for 3-D object.

    Kim, Hak Gu; Man Ro, Yong

    2017-11-27

    In this paper, we propose a new ultrafast layer based CGH calculation that exploits the sparsity of hologram fringe pattern in 3-D object layer. Specifically, we devise a sparse template holographic fringe pattern. The holographic fringe pattern on a depth layer can be rapidly calculated by adding the sparse template holographic fringe patterns at each object point position. Since the size of sparse template holographic fringe pattern is much smaller than that of the CGH plane, the computational load can be significantly reduced. Experimental results show that the proposed method achieves 10-20 msec for 1024x1024 pixels providing visually plausible results.

  16. Trial Manufacture and Evaluation of a Hologram with an unnecessary development process at 1.55 μm

    大島, 茂

    2016-01-01

    A holographic optical element (HOE) for optical fiber coupling has been investigated. The hologram with an unnecessary development process has been manufactured at wavelength of 1.55μm. Diimonium organic dye was used for photosensitive material. Because diimonium organic dye did not stick to a plate glass, acrylic resin was used for binder resin. The thin film of the organic dye was exposed by improved equipment for high power light irradiation at wavelength of 1.55μm. The thin film became th...

  17. Mutual transformation of light waves by reflection holograms in photorefractive crystals of the 4-bar 3m symmetry

    Naunyka, V. N.; Shepelevich, V. V., E-mail: vasshep@inbox.ru [Mozyr State Pedagogical University (Belarus)

    2011-05-15

    The mutual transformation of light waves in the case of their simultaneous diffraction from a bulk reflection phase hologram, which was formed in a cubic photorefractive crystal of the 4-bar 3m symmetry class, has been studied. The indicator surfaces of the polarization-optimized values of the relative intensity of the object wave, which make it possible to determine the amplification of this wave for any crystal cut, are constructed. The linear polarization azimuths at which the energy exchange between the light waves reaches a maximum are found numerically for crystals of different cuts.

  18. Pixel-size-maintained image reconstruction of digital holograms on arbitrarily tilted planes by the angular spectrum method.

    Jeong, Seung Jun; Hong, Chung Ki

    2008-06-01

    We present an effective method for the pixel-size-maintained reconstruction of images on arbitrarily tilted planes in digital holography. The method is based on the plane wave expansion of the diffraction wave fields and the three-axis rotation of the wave vectors. The images on the tilted planes are reconstructed without loss of the frequency contents of the hologram and have the same pixel sizes. Our method shows good results in the extreme cases of large tilting angles and in the region closer than the paraxial case. The effectiveness of the method is demonstrated by both simulation and experiment.

  19. Spatial-phase code-division multiple-access system with multiplexed Fourier holography switching for reconfigurable optical interconnection

    Takasago, Kazuya; Takekawa, Makoto; Shirakawa, Atsushi; Kannari, Fumihiko

    2000-05-01

    A new, to our knowledge, space-variant optical interconnection system based on a spatial-phase code-division multiple-access technique with multiplexed Fourier holography is described. In this technique a signal beam is spread over wide spatial frequencies by an M -sequence pseudorandom phase code. At a receiver side a selected signal beam is properly decoded, and at the same time its spatial pattern is shaped with a Fourier hologram, which is recorded by light that is encoded with the same M -sequence phase mask as the desired signal beam and by light whose spatial beam pattern is shaped to a signal routing pattern. Using the multiplexed holography, we can simultaneously route multisignal flows into individually specified receiver elements. The routing pattern can also be varied by means of switching the encoding phase code or replacing the hologram. We demonstrated a proof-of-principle experiment with a doubly multiplexed hologram that enables simultaneous routing of two signal beams. Using a numerical model, we showed that the proposed scheme can manage more than 250 routing patterns for one signal flow with one multiplexed hologram at a signal-to-noise ratio of 5.

  20. A transportable system for the in situ recording of color Denisyuk holograms of Greek cultural heritage artifacts in silver halide panchromatic emulsions and an optimized illuminating device for the finished holograms

    Sarakinos, A; Lembessis, A; Zervos, N

    2013-01-01

    In this paper we will present the Z-Lab transportable color holography system, the HoLoFoS illuminator and results of actual in situ recording of color Denisyuk holograms of artifacts on panchromatic silver halide emulsions. Z-lab and HoLoFoS were developed to meet identified prerequisites of holographic recording of artifacts: a) in situ recording b) a high degree of detail and color reproduction c) a low degree of image distortions. The Z-Lab consists of the Z3 RGB camera, its accessories and a mobile darkroom. HoLoFoS is an RGB LED-based lighting device for the display of color holograms. The device is capable of digitally controlled intensity mixing and provides a beam of uniform color cross section. The small footprint and emission characteristics of the device LEDs result in a narrow band, quasi point source at selected wavelengths. A case study in recording and displaying 'Optical Clones' of Greek cultural heritage artifacts with the aforementioned systems will also be presented.

  1. A transportable system for the in situ recording of color Denisyuk holograms of Greek cultural heritage artifacts in silver halide panchromatic emulsions and an optimized illuminating device for the finished holograms

    Sarakinos, A.; Lembessis, A.; Zervos, N.

    2013-02-01

    In this paper we will present the Z-Lab transportable color holography system, the HoLoFoS illuminator and results of actual in situ recording of color Denisyuk holograms of artifacts on panchromatic silver halide emulsions. Z-lab and HoLoFoS were developed to meet identified prerequisites of holographic recording of artifacts: a) in situ recording b) a high degree of detail and color reproduction c) a low degree of image distortions. The Z-Lab consists of the Z3RGB camera, its accessories and a mobile darkroom. HoLoFoS is an RGB LED-based lighting device for the display of color holograms. The device is capable of digitally controlled intensity mixing and provides a beam of uniform color cross section. The small footprint and emission characteristics of the device LEDs result in a narrow band, quasi point source at selected wavelengths. A case study in recording and displaying 'Optical Clones' of Greek cultural heritage artifacts with the aforementioned systems will also be presented.

  2. Multiple experimental approaches of immunotoxic effects of mercury chloride in the blue mussel, Mytilus edulis, through in vivo, in tubo and in vitro exposures

    Duchemin, Matthieu B.; Auffret, Michel; Wessel, Nathalie; Fortier, Marlene; Morin, Yves; Pellerin, Jocelyne; Fournier, Michel

    2008-01-01

    Biological impairments due to mercury discharge into the environment are now an issue of global concern. From the three forms of mercury found in aquatic ecosystems, the immunotoxic effects of mercury chloride were examined in the model animal, the blue mussel. In order to investigate the toxic potency of this chemical, three exposure regimes were carried out: chronic exposure of groups of individuals, a new protocol 'in tubo' designed for sub-acute exposures of individuals, and acute exposures of target cells. Chronic exposure revealed significant immunotoxic effects after 7 days at 10 -6 M, while acute exposures showed significant inhibition of phagocytosis at 10 -4 M and 10 -3 M. In sub-acute exposures both circulating haemocytes and haemocyte mortality increased at 10 -4 M and 10 -3 M while phagocytosis and the clearance rate drew hormetic toxic effects on healthy individuals. These results suggest the use of the 'in tubo' design for bivalve toxicological individual studies. - HgCl 2 impairs the immune system of test-tube mussels

  3. Cylindrical angular spectrum using Fourier coefficients of point light source and its application to fast hologram calculation.

    Oh, Seungtaik; Jeong, Il Kwon

    2015-11-16

    We will introduce a new simple analytic formula of the Fourier coefficient of the 3D field distribution of a point light source to generate a cylindrical angular spectrum which captures the object wave in 360° in the 3D Fourier space. Conceptually, the cylindrical angular spectrum can be understood as a cylindrical version of the omnidirectional spectral approach of Sando et al. Our Fourier coefficient formula is based on an intuitive observation that a point light radiates uniformly in all directions. Our formula is defined over all frequency vectors lying on the entire sphere in the 3D Fourier space and is more natural and computationally more efficient for all around recording of the object wave than that of the previous omnidirectional spectral method. A generalized frequency-based occlusion culling method for an arbitrary complex object is also proposed to enhance the 3D quality of a hologram. As a practical application of the cylindrical angular spectrum, an interactive hologram example is presented together with implementation details.

  4. Parallel computing of a digital hologram and particle searching for microdigital-holographic particle-tracking velocimetry

    Satake, Shin-ichi; Kanamori, Hiroyuki; Kunugi, Tomoaki; Sato, Kazuho; Ito, Tomoyoshi; Yamamoto, Keisuke

    2007-01-01

    We have developed a parallel algorithm for microdigital-holographic particle-tracking velocimetry. The algorithm is used in (1) numerical reconstruction of a particle image computer using a digital hologram, and (2) searching for particles. The numerical reconstruction from the digital hologram makes use of the Fresnel diffraction equation and the FFT (fast Fourier transform),whereas the particle search algorithm looks for local maximum graduation in a reconstruction field represented by a 3D matrix. To achieve high performance computing for both calculations (reconstruction and particle search), two memory partitions are allocated to the 3D matrix. In this matrix, the reconstruction part consists of horizontally placed 2D memory partitions on the x-y plane for the FFT, whereas, the particle search part consists of vertically placed 2D memory partitions set along the z axes.Consequently, the scalability can be obtained for the proportion of processor elements,where the benchmarks are carried out for parallel computation by a SGI Altix machine

  5. Design, fabrication and characterization of Computer Generated Holograms for anti-counterfeiting applications using OAM beams as light decoders.

    Ruffato, Gianluca; Rossi, Roberto; Massari, Michele; Mafakheri, Erfan; Capaldo, Pietro; Romanato, Filippo

    2017-12-21

    In this paper, we present the design, fabrication and optical characterization of computer-generated holograms (CGH) encoding information for light beams carrying orbital angular momentum (OAM). Through the use of a numerical code, based on an iterative Fourier transform algorithm, a phase-only diffractive optical element (PO-DOE) specifically designed for OAM illumination has been computed, fabricated and tested. In order to shape the incident beam into a helicoidal phase profile and generate light carrying phase singularities, a method based on transmission through high-order spiral phase plates (SPPs) has been used. The phase pattern of the designed holographic DOEs has been fabricated using high-resolution Electron-Beam Lithography (EBL) over glass substrates coated with a positive photoresist layer (polymethylmethacrylate). To the best of our knowledge, the present study is the first attempt, in a comprehensive work, to design, fabricate and characterize computer-generated holograms encoding information for structured light carrying OAM and phase singularities. These optical devices appear promising as high-security optical elements for anti-counterfeiting applications.

  6. Exposure to 3,3’,4,4’,5-pentachlorobiphenyl (PCB 126) impacts multiple organ systems in developing little skate (Leucoraja erinacea).

    Effects of exposure to coplanar polychlorinated biphenyls (PCBs) and other dioxin-like chemicals on developing vertebrates involve many organ systems, including the skeletal and cardiovascular systems. Apex predators, including those from the class Chondrichthyes (sharks, skates,...

  7. From Animal House to Old School: a multiple mediation analysis of the association between college drinking movie exposure and freshman drinking and its consequences.

    Osberg, Timothy M; Billingsley, Katherine; Eggert, Meredith; Insana, Maribeth

    2012-08-01

    Does exposure to college drinking movies impact upon subsequent college student drinking? If so, what mechanisms mediate such an effect? In the first study to address these questions, we assessed college drinking movie exposure in a sample of 479 college freshmen early in their first semester and examined its relation to subsequent drinking and drinking consequences one month later. Hypothesized mediators of this effect included college alcohol beliefs (beliefs that drinking is central to college life), positive and negative alcohol expectancies, and descriptive and injunctive norms. Using bootstrapping procedures, results indicated that movie exposure exerted direct effects on both drinking and drinking consequences. Movie exposure also had significant indirect effects on drinking through all of the hypothesized mediators, with the exception of negative alcohol expectancies. All mediated movie exposure's effects on drinking consequences, with the exception of injunctive norms. Contrast analyses revealed that college alcohol beliefs had the strongest mediational effects in the relationship between movie exposure and both drinking and consequences. The implications of these findings for precollege alcohol education programs are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. The impact of multiple interventions to reduce household exposure to second-hand tobacco smoke among women: a cluster randomized controlled trial in Kalutara district, Sri Lanka

    A. M. A. A. P. Alagiyawanna

    2017-10-01

    Full Text Available Abstract Background Second-hand smoke (SHS in households remains a serious public health problem in Sri Lanka, partly due to a lack of voluntary prohibitions of tobacco smoking inside houses. Women are especially at risk of being exposed. Effective community based interventions to reduce the SHS in households targeting women is scarce. The objective of this study was to examine the impact of a multi-component intervention on household SHS exposure among Sri Lankan women. Methods Thirty clusters of 25 women (aged 18–65 from 750 households were randomized into the intervention and control groups. Women in the intervention group were exposed to activities which focused on improving knowledge on the health effects of SHS, attitudes towards SHS exposure, right to a smoke-free living and women empowerment against smoking. The duration of the intervention was six months. The comparison group received no intervention. The primary outcome of interest was self-reported SHS exposure in the household within 7 days prior to data collection. The secondary outcomes were exposure in the past 30 days, knowledge of the health risks of exposure, attitudes towards exposure, right to smoke-free living, women empowerment against smoking, and smoking inside the homes. Results Final assessment was in 329 (89.6% in the intervention group and 309 (85.8% in the comparison group. Following the intervention, significantly lower proportion of women in the intervention group as compared to the control group reported SHS exposure in their households within 7-days (9.2% vs. 15.3%, p = 0.02 and 30-days (13.6% vs. 21.6%, p = 0.008 prior to the post survey. As compared to the control group, significantly higher median scores were observed in the intervention group on the knowledge of the health risks of exposure to SHS (p < 0.001, attitudes on exposure to SHS (p = 0.004, right to smoke free living (p = 0.001 and women empowerment (p < 0.001. Conclusion Multi

  9. Basic principles for the development of a concept for environmental exposure assessments of single substances released from multiple uses under REACH

    Gross, Rita; Bunke, Dirk [Oeko-Institut e.V. - Institut fuer Angewandte Oekologie e.V., Freiburg im Breisgau (Germany); Gartiser, Stefan [Hydrotox GmbH, Freiburg im Breisgau (Germany)

    2011-10-15

    The ECHA Guidance Documents R.12 to R.18 include detailed provisions on how to conduct an exposure assessment as part of the Chemical Safety Report. The guidance documents, however, only restrictedly address the consideration of a substance's emissions into the environment, if the local releases from various uses of the same substance result in a cumulative exposure. In a situation where a chemical has a number of applications in one site, it may however occur that the emissions of several uses which only have a low risk if considered separately will sum up and cause an unacceptable risk to the environment. Against this background, the objective of the present study is a further specification of the guidelines on cumulative risk assessment according to the REACH Regulation. Besides the definition of the key terminology, guidelines on cumulative exposure assessment already laid down in other legal regulations have been evaluated and their transferability to the environmental exposure assessment according to REACH has been investigated. Moreover, the fields of application for which a cumulative exposure assessment might be relevant have been worked out. A distinction was made between cases where the responsibility for cumulative exposure assessment falls into the hands of the registrant as part of the Chemical Safety Report and other cases, where the responsibility lies with the downstream users (DU) or the Member State Competent Authorities (MS-CA). Initial proposals have been elaborated for a technical implementation of the cumulative exposure assessment of chemicals as part of the preparation and evaluation of chemical dossiers by the registrant and the MS-CA, respectively, and as part of the responsibility of the DU. (orig.)

  10. [Multiple meningiomas].

    Terrier, L-M; François, P

    2016-06-01

    Multiple meningiomas (MMs) or meningiomatosis are defined by the presence of at least 2 lesions that appear simultaneously or not, at different intracranial locations, without the association of neurofibromatosis. They present 1-9 % of meningiomas with a female predominance. The occurrence of multiple meningiomas is not clear. There are 2 main hypotheses for their development, one that supports the independent evolution of these tumors and the other, completely opposite, that suggests the propagation of tumor cells of a unique clone transformation, through cerebrospinal fluid. NF2 gene mutation is an important intrinsic risk factor in the etiology of multiple meningiomas and some exogenous risk factors have been suspected but only ionizing radiation exposure has been proven. These tumors can grow anywhere in the skull but they are more frequently observed in supratentorial locations. Their histologic types are similar to unique meningiomas of psammomatous, fibroblastic, meningothelial or transitional type and in most cases are benign tumors. The prognosis of these tumors is eventually good and does not differ from the unique tumors except for the cases of radiation-induced multiple meningiomas, in the context of NF2 or when diagnosed in children where the outcome is less favorable. Each meningioma lesion should be dealt with individually and their multiple character should not justify their resection at all costs. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  11. Medium wave exposure characterisation using exposure quotients.

    Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Antolín, Alicia; Pinar, Iván

    2010-06-01

    One of the aspects considered in the International Commission on Non-Ionizing Radiation Protection guidelines is that, in situations of simultaneous exposure to fields of different frequencies, exposure quotients for thermal and electrical stimulation effects should be examined. The aim of the present work was to analyse the electromagnetic radiation levels and exposure quotients for exposure to multiple-frequency sources in the vicinity of medium wave radio broadcasting antennas. The measurements were made with a spectrum analyser and a monopole antenna. Kriging interpolation was used to prepare contour maps and to estimate the levels in the towns and villages of the zone. The results showed that the exposure quotient criterion based on electrical stimulation effects to be more stringent than those based on thermal effects or power density levels. Improvement of dosimetry evaluations requires the spectral components of the radiation to be quantified, followed by application of the criteria for exposure to multiple-frequency sources.

  12. Is it possible to embed a 4D, N=4 supersymmetric vector multiplet within a completely off-shell adinkra hologram?

    Calkins, Mathew; Gates, D.E.A.; Gates, Sylvester James Jr.; McPeak, Brian [Center for String and Particle Theory, Department of Physics, University of Maryland,College Park, MD 20742-4111 (United States)

    2014-05-13

    We present evidence of the existence of a 1D, N = 16 SUSY hologram that can be used to understand representation theory aspects of a 4D, N = 4 supersymmetrical vector multiplet. In this context, the long-standing “off-shell SUSY” problem for the 4D, N = 4 Maxwell supermultiplet is precisely formulated as a problem in linear algebra.

  13. Corporeality as the Hologram of Mythological Content (Based on the Prose of the Ukrainian Diaspora of the 1920s–1950s

    Olha Slonovska

    2017-10-01

    Full Text Available The role and the place of the artistic truth and artistic speculation are a promising area of theoretical and practical explorations. The focus of this study is on the mythical-poetic hologram of the human body as a specific information carrier which comprises a range of important markers.

  14. Environmentally relevant concentrations of di(2-ethylhexyl)phthalate exposure alter larval growth and locomotion in medaka fish via multiple pathways.

    Yang, Wen-Kai; Chiang, Li-Fen; Tan, Shi-Wei; Chen, Pei-Jen

    2018-06-01

    Di(2-ethylhexyl)phthalate (DEHP) is a commonly used plasticizer, with evidence of ubiquitous human exposure and widespread occurrence in the aquatic environment. It is an emerging environmental pollutant with regulatory priority; however, most studies have focused on the toxicity of DEHP related to endocrine disruption and reproduction in mammals. The ecotoxicological impact of phthalates (e.g., DEHP) on early life stages of fish under environmentally relevant concentrations of chronic exposure remains unclear. In this study, 7-day post-hatching fry of medaka fish (Oryzias latipes) underwent 21-day continuous exposure to DEHP solutions at 20, 100 and 200 μg/L to assess the effects on fish development and locomotion and related toxic mechanisms. Larval mortality was low with DEHP (20-200 μg/L) within 21 days, but such exposure significantly reduced fish body weight and length and altered swimming behavior. At 21 days, DEHP exposure resulted in specific patterns of larval locomotion (e.g., increased maximum velocity and absolute turn angle) and dose-dependently increased the mRNA expression of acetylcholinesterase (ache) but did not alter AChE activity. Transcriptional expression of antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase and peroxisome proliferation-activated receptor and retinoid X receptor genes was significantly suppressed with 21-day DEHP exposure (20-200 μg/L), with marginal alteration in reactive oxygen species levels and antioxidant activities within the dosing period. As well, DEHP altered the mRNA expression of p53-regulated apoptosis pathways, such as upregulated p53, p21 and bcl-2 and downregulated caspase-3 expression, with increased enzymatic activity of caspase-3 in larvae. Our results suggest that toxic mechanisms of waterborne DEHP altered fish growth and locomotion likely via a combined effect of oxidative stress, neurotoxicity and apoptosis pathways. Copyright © 2018

  15. Effects of Exposure to Acetaminophen and Ibuprofen on Fetal Germ Cell Development in Both Sexes in Rodent and Human Using Multiple Experimental Systems

    Hurtado-Gonzalez, Pablo; Anderson, Richard A; Macdonald, Joni

    2018-01-01

    /ovaries using in vitro and xenograft approaches. METHODS: Gonocyte (TFAP2C+) number was reduced relative to controls in first-trimester human fetal testes exposed in vitro to acetaminophen (-28%) or ibuprofen (-22%) and also in ovaries exposed to acetaminophen (-43%) or ibuprofen (-49%). Acetaminophen exposure...

  16. Health risk assessment of various metal(loid)s via multiple exposure pathways on children living near a typical lead-acid battery plant, China

    Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

    2015-01-01

    Manufacture of lead-acid batteries is of widespread interest because of its emissions of heavy metals and metalloids into environment, harming environmental quality and consequently causing detrimental effects on human health. In this study, exposure pathways and health risks of children to heavy metal(loid)s (Pb, Cd, As, etc) were investigated based on field sampling and questionnaire. Pb was one of the most abundant elements in children's blood, with an elevated blood lead level of 12.45 μg dL −1 . Soil/dust and food were heavily polluted by targeted metal(loid)s. Food ingestion accounted for more than 80% of the total exposure for most metal(loid)s. The non-cancer risks to children were 3–10 times higher than the acceptable level of 1, while the cancer risks were 5–200 times higher than the maximum acceptable level of 1.0 × 10 −4 . The study emphasized the significance of effective environmental management, particularly to ensure food security near battery facilities. - Highlights: • The health risks of children living around a typical lead-acid battery was analyzed. • The exposure pathways of children to 12 heavy metal(loid)s were assessed. • Courtyard soil and indoor dust and duplicate food were contaminated by metal(loid)s. • Food ingestion was the major pathway for children's exposure to most metal(loid)s. • Higher potentially non-cancer and cancer risks happened to the local children. - The children living around a typical lead-acid battery plant suffered from serious health risks, which mainly attributed to food ingestion and air inhalation exposure

  17. Bessel function expansion to reduce the calculation time and memory usage for cylindrical computer-generated holograms.

    Sando, Yusuke; Barada, Daisuke; Jackin, Boaz Jessie; Yatagai, Toyohiko

    2017-07-10

    This study proposes a method to reduce the calculation time and memory usage required for calculating cylindrical computer-generated holograms. The wavefront on the cylindrical observation surface is represented as a convolution integral in the 3D Fourier domain. The Fourier transformation of the kernel function involving this convolution integral is analytically performed using a Bessel function expansion. The analytical solution can drastically reduce the calculation time and the memory usage without any cost, compared with the numerical method using fast Fourier transform to Fourier transform the kernel function. In this study, we present the analytical derivation, the efficient calculation of Bessel function series, and a numerical simulation. Furthermore, we demonstrate the effectiveness of the analytical solution through comparisons of calculation time and memory usage.

  18. High-fidelity phase and amplitude control of phase-only computer generated holograms using conjugate gradient minimisation.

    Bowman, D; Harte, T L; Chardonnet, V; De Groot, C; Denny, S J; Le Goc, G; Anderson, M; Ireland, P; Cassettari, D; Bruce, G D

    2017-05-15

    We demonstrate simultaneous control of both the phase and amplitude of light using a conjugate gradient minimisation-based hologram calculation technique and a single phase-only spatial light modulator (SLM). A cost function, which incorporates the inner product of the light field with a chosen target field within a defined measure region, is efficiently minimised to create high fidelity patterns in the Fourier plane of the SLM. A fidelity of F = 0.999997 is achieved for a pattern resembling an LG10 mode with a calculated light-usage efficiency of 41.5%. Possible applications of our method in optical trapping and ultracold atoms are presented and we show uncorrected experimental realisation of our patterns with F = 0.97 and 7.8% light efficiency.

  19. A randomized, multicentre study of directed daylight exposure times of 11/2 vs. 21/2 h in daylight-mediated photodynamic therapy with methyl aminolaevulinate in patients with multiple thin actinic keratoses of the face and scalp

    Wiegell, S.R.; Fabricius, S.; Philipsen, P.A.

    2011-01-01

    , time of day or time of year during which the treatment was performed. Treatment was well tolerated, with a mean ± SD maximal pain score of 1·3 ± 1·5. Conclusions: Daylight-mediated MAL-PDT is an effective, convenient and nearly pain-free treatment for patients with multiple thin AKs. Daylight-mediated......, the inconvenience of clinic attendance and discomfort during therapy are significant drawbacks. Daylight-mediated PDT could potentially reduce these and may serve as an alternative to conventional PDT. Objectives: To compare the efficacy of methyl aminolaevulinate (MAL)-PDT with 11/2 vs. 21/2 h of daylight exposure...

  20. Integrating multiple stressors across life stages and latitudes: Combined and delayed effects of an egg heat wave and larval pesticide exposure in a damselfly.

    Sniegula, Szymon; Janssens, Lizanne; Stoks, Robby

    2017-05-01

    To understand the effects of pollutants in a changing world we need multistressor studies that combine pollutants with other stressors associated with global change such as heat waves. We tested for the delayed and combined impact of a heat wave during the egg stage and subsequent sublethal exposure to the pesticide esfenvalerate during the larval stage on life history and physiology in the larval and adult stage of the damselfly Lestes sponsa. We studied this in a common garden experiment with replicated central- and high latitude populations to explore potential effects of local thermal adaptation and differences in life history shaping the multistressor responses. Exposure of eggs to the heat wave had no effect on larval traits, yet had delayed costs (lower fat and flight muscle mass) in the adult stage thereby crossing two life history transitions. These delayed costs were only present in central-latitude populations potentially indicating their lower heat tolerance. Exposure of larvae to the pesticide reduced larval growth rate and prolonged development time, and across metamorphosis reduced the adult fat content and the flight muscle mass, yet did not affect the adult heat tolerance. The pesticide-induced delayed emergence was only present in the slower growing central-latitude larvae, possibly reflecting stronger selection to keep development fast in the more time-constrained high-latitude populations. We observed no synergistic interactions between the egg heat wave and the larval pesticide exposure. Instead the pesticide-induced reduction in fat content was only present in animals that were not exposed to the egg heat wave. Our results based on laboratory conditions highlight that multistressor studies should integrate across life stages to fully capture cumulative effects of pollutants with other stressors related to global change. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Concurrent Fetal Exposure to Multiple Environmental Chemicals along the U.S.—Mexico Border: An Exploratory Study in Brownsville, Texas

    Ken Sexton

    2014-09-01

    Full Text Available There is mounting concern that cumulative exposure to diverse chemicals in the environment may contribute to observed adverse health outcomes in the Lower Rio Grande Valley of Texas. To investigate this situation, biomarker concentrations of organochlorine (OC pesticides/metabolites, polychlorinated biphenyls (PCBs, and polycyclic aromatic hydrocarbons (PAHs were measured in maternal and umbilical cord blood from pregnant Hispanic women in Brownsville, TX. Results show that both mothers and fetuses were exposed concurrently to a variety of relatively low-level, hazardous environmental chemicals. Approximately 10% of the blood specimens had comparatively high concentrations of specific OC pesticides, PCBs and PAHs. Because many pregnant women in Brownsville live in socioeconomically-disadvantaged and environmentally-challenging circumstances, there is appropriate concern that exposure to these exogenous substances, either individually or in combination, may contribute to endemic health problems in this population, including cardiovascular disease, obesity, and diabetes.  The challenge is to identify individuals at highest comparative risk and then implement effective programs to either prevent or reduce cumulative exposures that pose significant health-related threats.

  2. Evaluation of sub-zero and residence times after continuous versus multiple intermittent cryogen spray cooling exposure on human skin phantom

    Ramirez-San-Juan, JC; Tuqan, AT; Kelly, KM; Nelson, JS; Aguilar, G

    2004-01-01

    Cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during various laser dermatologic surgeries. However, as the application of single or multiple cryogen spurts becomes available on some commercial lasers devices, it is necessary to determine the optimal CSC parameters for different laser surgeries. The objective of this study was to measure the time the sprayed surface of a human skin phantom (HSP) remains below water freezing temperature 0°C, referred to as subzero...

  3. Response of heat shock protein genes of the oriental fruit moth under diapause and thermal stress reveals multiple patterns dependent on the nature of stress exposure.

    Zhang, Bo; Peng, Yu; Zheng, Jincheng; Liang, Lina; Hoffmann, Ary A; Ma, Chun-Sen

    2016-07-01

    Heat shock protein gene (Hsp) families are thought to be important in thermal adaptation, but their expression patterns under various thermal stresses have still been poorly characterized outside of model systems. We have therefore characterized Hsp genes and their stress responses in the oriental fruit moth (OFM), Grapholita molesta, a widespread global orchard pest, and compared patterns of expression in this species to that of other insects. Genes from four Hsp families showed variable expression levels among tissues and developmental stages. Members of the Hsp40, 70, and 90 families were highly expressed under short exposures to heat and cold. Expression of Hsp40, 70, and Hsc70 family members increased in OFM undergoing diapause, while Hsp90 was downregulated. We found that there was strong sequence conservation of members of large Hsp families (Hsp40, Hsp60, Hsp70, Hsc70) across taxa, but this was not always matched by conservation of expression patterns. When the large Hsps as well as small Hsps from OFM were compared under acute and ramping heat stress, two groups of sHsps expression patterns were apparent, depending on whether expression increased or decreased immediately after stress exposure. These results highlight potential differences in conservation of function as opposed to sequence in this gene family and also point to Hsp genes potentially useful as bioindicators of diapause and thermal stress in OFM.

  4. Sustained Interleukin-1β Exposure Modulates Multiple Steps in Glucocorticoid Receptor Signaling, Promoting Split-Resistance to the Transactivation of Prominent Anti-Inflammatory Genes by Glucocorticoids

    Pedro Escoll

    2015-01-01

    Full Text Available Clinical treatment with glucocorticoids (GC can be complicated by cytokine-induced glucocorticoid low-responsiveness (GC-resistance, GCR, a condition associated with a homogeneous reduction in the expression of GC-receptor- (GR- driven anti-inflammatory genes. However, GR level and phosphorylation changes modify the expression of individual GR-responsive genes differently. As sustained IL-1β exposure is key in the pathogenesis of several major diseases with prevalent GCR, we examined GR signaling and the mRNA expression of six GR-driven genes in cells cultured in IL-1β and afterwards challenged with GC. After a GC challenge, sustained IL-1β exposure reduced the cytoplasmic GR level, GRSer203 and GRSer211 phosphorylation, and GR nuclear translocation and led to selective GCR in the expression of the studied genes. Compared to GC alone, in a broad range of GC doses plus sustained IL-1β, FKBP51 mRNA expression was reduced by 1/3, TTP by 2/3, and IRF8 was completely knocked down. In contrast, high GC doses did not change the expression of GILZ and DUSP1, while IGFBP1 was increased by 5-fold. These effects were cytokine-selective, IL-1β dose- and IL-1R1-dependent. The integrated gain and loss of gene functions in the “split GCR” model may provide target cells with a survival advantage by conferring resistance to apoptosis, chemotherapy, and GC.

  5. Radiation risk to the patient: a case study involving multiple diagnostic X ray exposures given over a period of 25 years

    Rainbow, A.J.; McMaster Univ., Hamilton, ON; Roginski, P.; McGeen, W.

    1992-01-01

    The cumulative somatic dose index (SDI) for a number of diagnostic X ray examinations was made for a 60 year old male. The history of diagnostic X ray exposure for this patient from 1957 to 1983 showed 29 diagnostic X ray examinations including more than 100 films and 15 minutes of fluoroscopy. The total cumulative SDI to this patient was 214 mGy (about 21 rad). More than half this dose, 142 mGy, was contributed from upper GI and barium enema examinations which used fluoroscopy, with 88 mGy from the fluoroscopy alone. Using the recently revised risk coefficient for fatal cancer following whole-body irradiation of adult workers recommended by the International Commission on Radiological Protection in 1990, the authors estimate a 0.9% cancer morality risk to this patient resulting from the 29 diagnostic X ray examinations. (author)

  6. Prevalence and associated demographic characteristics of exposure to multiple metals and their species in human populations: The United States NHANES, 2007-2012.

    Shim, Youn K; Lewin, Michael D; Ruiz, Patricia; Eichner, June E; Mumtaz, Moiz M

    2017-01-01

    Lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) are among the top 10 pollutants of global health concern. Studies have shown that exposures to these metals produce severe adverse effects. However, the mechanisms underlying these effects, particularly joint toxicities, are poorly understood in humans. The objective of this investigation was to identify and characterize prevalent combinations of these metals and their species in the U.S. NHANES population to provide background data for future studies of potential metal interactions. Exposure was defined as urine or blood levels ≥ medians of the NHANES 2007-2012 participants ≥6 years (n = 7408). Adjusted-odds ratios (adj-OR) and 95% confidence intervals were determined for covariates (age, gender, and race/ethnicity, cotinine and body mass index). Species-specific analysis was also conducted for As and Hg including iAs (urinary arsenous acid and/or arsenic acid), met-iAs (urinary monomethylarsonic acid and/or dimethylarsinic acid), and oHg (blood methyl-mercury and/or ethyl-mercury). For combinations of As and Hg species, age- and gender-specific prevalence was determined among NHANES 2011-2012 participants (n = 2342). Data showed that approximately 49.3% of the population contained a combination of three or more metals. The most prevalent unique specific combinations were Pb/Cd/Hg/As, Pb/Cd/Hg, and Pb/Cd. Age was consistently associated with these combinations: adj-ORs ranged from 10.9 (Pb/Cd) to 11.2 (Pb/Cd/Hg/As). Race/ethnicity was significant for Pb/Cd/Hg/As. Among women of reproductive age, frequency of oHg/iAs/met-iAS and oHg/met-iAs was 22.9 and 40.3%, respectively. These findings may help prioritize efforts to assess joint toxicities and their impact on public health.

  7. Assessing possible DSM-5 ASD subtypes in a sample of victims meeting caseness for DSM-5 ASD based on self-report following multiple forms of traumatic exposure.

    Hansen, Maj; Armour, Cherie; Wang, Li; Elklit, Ask; Bryant, Richard A

    2015-04-01

    Acute stress disorder (ASD) was introduced into the DSM-IV to recognize early traumatic responses and as a precursor of PTSD. Although the diagnostic criteria for ASD were altered and structured more similarly to the PTSD definition in DSM-5, only the PTSD diagnosis includes a dissociative subtype. Emerging research has indicated that there also appears to be a highly symptomatic subtype for ASD. However, the specific nature of the subtype is currently unclear. The present study investigates the possible presence of ASD subtypes in a mixed sample of victims meeting caseness for DSM-5 ASD based on self-report following four different types of traumatic exposure (N=472). The results of latent profile analysis revealed a 5-class solution. The highly symptomatic class was marked by high endorsement on avoidance and dissociation compared to the other classes. Findings are discussed in regard to its clinical implications including the implications for the pending the ICD-11 and the recently released DSM-5. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Integrating data from multiple time-location measurement methods for use in exposure assessment: the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air).

    Hazlehurst, Marnie F; Spalt, Elizabeth W; Curl, Cynthia L; Davey, Mark E; Vedal, Sverre; Burke, Gregory L; Kaufman, Joel D

    2017-11-01

    Tools to assess time-location patterns related to environmental exposures have expanded from reliance on time-location diaries (TLDs) and questionnaires to use of geospatial location devices such as data-logging Global Positioning System (GPS) equipment. The Multi-Ethnic Study of Atherosclerosis and Air Pollution obtained typical time-location patterns via questionnaire for 6424 adults in six US cities. At a later time (mean 4.6 years after questionnaire), a subset (n=128) participated in high-resolution data collection for specific 2-week periods resulting in concurrent GPS and detailed TLD data, which were aggregated to estimate time spent in various microenvironments. During these 2-week periods, participants were observed to spend the most time at home indoors (mean of 78%) and a small proportion of time in-vehicle (mean of 4%). Similar overall patterns were reported by these participants on the prior questionnaire (mean home indoors: 75%; mean in-vehicle: 4%). However, individual micro-environmental time estimates measured over specific 2-week periods were not highly correlated with an individual's questionnaire report of typical behavior (Spearman's ρ of 0.43 for home indoors and 0.39 for in-vehicle). Although questionnaire data about typical time-location patterns can inform interpretation of long-term epidemiological analyses and risk assessment, they may not reliably represent an individual's short-term experience.

  9. Values and Preferences on the Use of Oral Pre-exposure Prophylaxis (PrEP) for HIV Prevention Among Multiple Populations: A Systematic Review of the Literature.

    Koechlin, Florence M; Fonner, Virginia A; Dalglish, Sarah L; O'Reilly, Kevin R; Baggaley, Rachel; Grant, Robert M; Rodolph, Michelle; Hodges-Mameletzis, Ioannis; Kennedy, Caitlin E

    2017-05-01

    Daily oral pre-exposure prophylaxis (PrEP) is the use of antiretroviral drugs by HIV-negative people to prevent HIV infection. WHO released new guidelines in 2015 recommending PrEP for all populations at substantial risk of HIV infection. To prepare these guidelines, we conducted a systematic review of values and preferences among populations that might benefit from PrEP, women, heterosexual men, young women and adolescent girls, female sex workers, serodiscordant couples, transgender people and people who inject drugs, and among healthcare providers who may prescribe PrEP. A comprehensive search strategy reviewed three electronic databases of articles and HIV-related conference abstracts (January 1990-April 2015). Data abstraction used standardised forms to categorise by population groups and relevant themes. Of 3068 citations screened, 76 peer-reviewed articles and 28 conference abstracts were included. Geographic coverage was global. Most studies (N = 78) evaluated hypothetical use of PrEP, while 26 studies included individuals who actually took PrEP or placebo. Awareness of PrEP was low, but once participants were presented with information about PrEP, the majority said they would consider using it. Concerns about safety, side effects, cost and effectiveness were the most frequently cited barriers to use. There was little indication of risk compensation. Healthcare providers would consider prescribing PrEP, but need more information before doing so. Findings from a rapidly expanding evidence base suggest that the majority of populations most likely to benefit from PrEP feel positively towards it. These same populations would benefit from overcoming current implementation challenges with the shortest possible delay.

  10. No adverse effects detected for simultaneous whole-body exposure to multiple-frequency radiofrequency electromagnetic fields for rats in the intrauterine and pre- and post-weaning periods

    Shirai, Tomoyuki; Wang, Jianqing; Kawabe, Mayumi; Wake, Kanako; Watanabe, So-ichi; Takahashi, Satoru; Fujiwara, Osamu

    2017-01-01

    In everyday life, people are exposed to radiofrequency (RF) electromagnetic fields (EMFs) with multiple frequencies. To evaluate the possible adverse effects of multifrequency RF EMFs, we performed an experiment in which pregnant rats and their delivered offspring were simultaneously exposed to eight different communication signal EMFs (two of 800 MHz band, two of 2 GHz band, one of 2.4 GHz band, two of 2.5 GHz band and one of 5.2 GHz band). Thirty six pregnant Sprague-Dawley (SD) 10-week-old rats were divided into three groups of 12 rats: one control (sham exposure) group and two experimental (low- and high-level RF EMF exposure) groups. The whole body of the mother rats was exposed to the RF EMFs for 20 h per day from Gestational Day 7 to weaning, and F 1 offspring rats (46–48 F1 pups per group) were then exposed up to 6 weeks of age also for 20 h per day. The parameters evaluated included the growth, gestational condition and organ weights of the dams; the survival rates, development, growth, physical and functional development, memory function, and reproductive ability of the F 1 offspring; and the embryotoxicity and teratogenicity in the F 2 rats. No abnormal findings were observed in the dams or F 1 offspring exposed to the RF EMFs or to the F 2 offspring for any of the parameters evaluated. Thus, under the conditions of the present experiment, simultaneous whole-body exposure to eight different communication signal EMFs at frequencies between 800 MHz and 5.2 GHz did not show any adverse effects on pregnancy or on the development of rats.

  11. The Hologram in My Hand: How Effective is Interactive Exploration of 3D Visualizations in Immersive Tangible Augmented Reality?

    Bach, Benjamin

    2017-08-29

    We report on a controlled user study comparing three visualization environments for common 3D exploration. Our environments differ in how they exploit natural human perception and interaction capabilities. We compare an augmented-reality head-mounted display (Microsoft HoloLens), a handheld tablet, and a desktop setup. The novel head-mounted HoloLens display projects stereoscopic images of virtual content into a user\\'s real world and allows for interaction in-situ at the spatial position of the 3D hologram. The tablet is able to interact with 3D content through touch, spatial positioning, and tangible markers, however, 3D content is still presented on a 2D surface. Our hypothesis is that visualization environments that match human perceptual and interaction capabilities better to the task at hand improve understanding of 3D visualizations. To better understand the space of display and interaction modalities in visualization environments, we first propose a classification based on three dimensions: perception, interaction, and the spatial and cognitive proximity of the two. Each technique in our study is located at a different position along these three dimensions. We asked 15 participants to perform four tasks, each task having different levels of difficulty for both spatial perception and degrees of freedom for interaction. Our results show that each of the tested environments is more effective for certain tasks, but that generally the desktop environment is still fastest and most precise in almost all cases.

  12. The Hologram in My Hand: How Effective is Interactive Exploration of 3D Visualizations in Immersive Tangible Augmented Reality?

    Bach, Benjamin; Sicat, Ronell; Beyer, Johanna; Cordeil, Maxime; Pfister, Hanspeter

    2018-01-01

    We report on a controlled user study comparing three visualization environments for common 3D exploration. Our environments differ in how they exploit natural human perception and interaction capabilities. We compare an augmented-reality head-mounted display (Microsoft HoloLens), a handheld tablet, and a desktop setup. The novel head-mounted HoloLens display projects stereoscopic images of virtual content into a user's real world and allows for interaction in-situ at the spatial position of the 3D hologram. The tablet is able to interact with 3D content through touch, spatial positioning, and tangible markers, however, 3D content is still presented on a 2D surface. Our hypothesis is that visualization environments that match human perceptual and interaction capabilities better to the task at hand improve understanding of 3D visualizations. To better understand the space of display and interaction modalities in visualization environments, we first propose a classification based on three dimensions: perception, interaction, and the spatial and cognitive proximity of the two. Each technique in our study is located at a different position along these three dimensions. We asked 15 participants to perform four tasks, each task having different levels of difficulty for both spatial perception and degrees of freedom for interaction. Our results show that each of the tested environments is more effective for certain tasks, but that generally the desktop environment is still fastest and most precise in almost all cases.

  13. Analysis of the hologram recording on the novel chloride photo-thermo-refractive glass

    Ivanov, S. A.; Nikonorov, N. V.; Dubrovin, V. D.; Krykova, V. A.

    2017-05-01

    In this research, we present new holographic material based on fluoride photo-thermo-refractive glass(PTR) - chloride PTR glass. One of the benefit of this type of PTR glass is positive refractive index change. During this work, for the first-time volume Bragg gratings were recorded in this kind of material. The first experiments revealed that such gratings are mixed i.e. possess both absorption and phase components. Complex analysis shows that both refractive index and absorption coefficient are modulated inside the grating structure. We found out that at first there is no strict dependence of the refractive index change from dosage, but as we continue the process of thermal treatment - dependence is appear. Exposure influence on the refractive index change for this glass differs from fluoride one and shows some sort of saturation after the exposure of 4-6 J/cm2 . We distinguished refractive index change and absorption coefficient change and observed both behavior with increasing thermal treatment time. We found out that the increase of thermal treatment time results in the significant refractive index change. At the same time the absorption does `not practically change. It was found that maximum modulation of refractive index is comparable with fluoride PTR glass and achieves value of 1600 ppm. The modulation of absorption is equal to induced absorption caused by silver nanoparticles and depends from reading wavelength. Our study shows that almost all absorption is modulated inside the grating.

  14. Rotational scanning and multiple-spot focusing through a multimode fiber based on digital optical phase conjugation

    Ma, Chaojie; Di, Jianglei; Li, Ying; Xiao, Fajun; Zhang, Jiwei; Liu, Kaihui; Bai, Xuedong; Zhao, Jianlin

    2018-06-01

    We demonstrate, for the first time, the rotational memory effect of a multimode fiber (MMF) based on digital optical phase conjugation (DOPC) to achieve multiple-spot focusing. An implementation interferometer is used to address the challenging alignments in DOPC. By rotating the acquired phase conjugate pattern, rotational scanning through a MMF could be achieved by recording a single off-axis hologram. The generation of two focal spots through a MMF is also demonstrated by combining the rotational memory effect with the superposition principle. The results may be useful for ultrafast scanning imaging and optical manipulation of multiple objects through a MMF.

  15. Exposure Forecaster

    U.S. Environmental Protection Agency — The Exposure Forecaster Database (ExpoCastDB) is EPA's database for aggregating chemical exposure information and can be used to help with chemical exposure...

  16. Angular multiplexing holograms of four images recorded on photopolymer films with recording-film-thickness-dependent holographic characteristics

    Osabe, Keiichi; Kawai, Kotaro

    2017-03-01

    In this study, angular multiplexing hologram recording photopolymer films were studied experimentally. The films contained acrylamide as a monomer, eosin Y as a sensitizer, and triethanolamine as a promoter in a polyvinyl alcohol matrix. In order to determine the appropriate thickness of the photopolymer films for angular multiplexing, photopolymer films with thicknesses of 29-503 μm were exposed to two intersecting beams of a YVO laser at a wavelength of 532 nm to form a holographic grating with a spatial frequency of 653 line/mm. The diffraction efficiencies as a function of the incident angle of reconstruction were measured. A narrow angular bandwidth and high diffraction efficiency are required for angular multiplexing; hence, we define the Q value, which is the diffraction efficiency divided by half the bandwidth. The Q value of the films depended on the thickness of the films, and was calculated based on the measured diffraction efficiencies. The Q value of a 297-μm-thick film was the highest of the all films. Therefore, the angular multiplexing experiments were conducted using 300-μm-thick films. In the angular multiplexing experiments, the object beam transmitted by a square aperture was focused by a Fourier transform lens and interfered with a reference beam. The maximum order of angular multiplexing was four. The signal intensity that corresponds to the squared-aperture transmission and the noise intensity that corresponds to transmission without the square aperture were measured. The signal intensities decreased as the order of angular multiplexing increased, and the noise intensities were not dependent on the order of angular multiplexing.

  17. Multiple chemical sensitivity

    Tran, Marie Thi Dao; Arendt-Nielsen, Lars; Kupers, Ron

    2013-01-01

    BACKGROUND: Multiple Chemical Sensitivity (MCS) is a chronic condition characterized by recurrent, non-specific symptoms in response to chemically unrelated exposures in non-toxic concentrations. Although the pathophysiology of MCS remains unknown, central sensitization may be an important factor...

  18. Multiple Perspectives / Multiple Readings

    Simon Biggs

    2005-01-01

    Full Text Available People experience things from their own physical point of view. What they see is usually a function of where they are and what physical attitude they adopt relative to the subject. With augmented vision (periscopes, mirrors, remote cameras, etc we are able to see things from places where we are not present. With time-shifting technologies, such as the video recorder, we can also see things from the past; a time and a place we may never have visited.In recent artistic work I have been exploring the implications of digital technology, interactivity and internet connectivity that allow people to not so much space/time-shift their visual experience of things but rather see what happens when everybody is simultaneously able to see what everybody else can see. This is extrapolated through the remote networking of sites that are actual installation spaces; where the physical movements of viewers in the space generate multiple perspectives, linked to other similar sites at remote locations or to other viewers entering the shared data-space through a web based version of the work.This text explores the processes involved in such a practice and reflects on related questions regarding the non-singularity of being and the sense of self as linked to time and place.

  19. Quantitative measurement of mean inner potential and specimen thickness from high-resolution off-axis electron holograms of ultra-thin layered WSe{sub 2}

    Winkler, Florian, E-mail: f.winkler@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Tavabi, Amir H. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Barthel, Juri [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Gemeinschaftslabor für Elektronenmikroskopie (GFE), RWTH Aachen University, D-52074 Aachen (Germany); Duchamp, Martial [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Yucelen, Emrah [FEI Company, Achtseweg Noord 5, Eindhoven 5600 KA (Netherlands); Borghardt, Sven; Kardynal, Beata E. [Peter Grünberg Institute 9 (PGI-9), Forschungszentrum Jülich, D-52425 Jülich (Germany); and others

    2017-07-15

    The phase and amplitude of the electron wavefunction that has passed through ultra-thin flakes of WSe{sub 2} is measured from high-resolution off-axis electron holograms. Both the experimental measurements and corresponding computer simulations are used to show that, as a result of dynamical diffraction, the spatially averaged phase does not increase linearly with specimen thickness close to an [001] zone axis orientation even when the specimen has a thickness of only a few layers. It is then not possible to infer the local specimen thickness of the WSe{sub 2} from either the phase or the amplitude alone. Instead, we show that the combined analysis of phase and amplitude from experimental measurements and simulations allows an accurate determination of the local specimen thickness. The relationship between phase and projected potential is shown to be approximately linear for extremely thin specimens that are tilted by several degrees in certain directions from the [001] zone axis. A knowledge of the specimen thickness then allows the electrostatic potential to be determined from the measured phase. By using this combined approach, we determine a value for the mean inner potential of WSe{sub 2} of 18.9±0.8 V, which is 12% lower than the value calculated from neutral atom scattering factors. - Highlights: • Quantitative analysis of high resolution electron holograms of WSe{sub 2}. • Local specimen thickness determination and estimation of tilt angle. • Mean inner potential evaluation of WSe2 avoiding dynamical diffraction.

  20. Fast generation of video holograms of three-dimensional moving objects using a motion compensation-based novel look-up table.

    Kim, Seung-Cheol; Dong, Xiao-Bin; Kwon, Min-Woo; Kim, Eun-Soo

    2013-05-06

    A novel approach for fast generation of video holograms of three-dimensional (3-D) moving objects using a motion compensation-based novel-look-up-table (MC-N-LUT) method is proposed. Motion compensation has been widely employed in compression of conventional 2-D video data because of its ability to exploit high temporal correlation between successive video frames. Here, this concept of motion-compensation is firstly applied to the N-LUT based on its inherent property of shift-invariance. That is, motion vectors of 3-D moving objects are extracted between the two consecutive video frames, and with them motions of the 3-D objects at each frame are compensated. Then, through this process, 3-D object data to be calculated for its video holograms are massively reduced, which results in a dramatic increase of the computational speed of the proposed method. Experimental results with three kinds of 3-D video scenarios reveal that the average number of calculated object points and the average calculation time for one object point of the proposed method, have found to be reduced down to 86.95%, 86.53% and 34.99%, 32.30%, respectively compared to those of the conventional N-LUT and temporal redundancy-based N-LUT (TR-N-LUT) methods.

  1. Three-directional motion compensation-based novel-look-up-table for video hologram generation of three-dimensional objects freely maneuvering in space.

    Dong, Xiao-Bin; Kim, Seung-Cheol; Kim, Eun-Soo

    2014-07-14

    A new three-directional motion compensation-based novel-look-up-table (3DMC-NLUT) based on its shift-invariance and thin-lens properties, is proposed for video hologram generation of three-dimensional (3-D) objects moving with large depth variations in space. The input 3-D video frames are grouped into a set of eight in sequence, where the first and remaining seven frames in each set become the reference frame (RF) and general frames (GFs), respectively. Hence, each 3-D video frame is segmented into a set of depth-sliced object images (DOIs). Then x, y, and z-directional motion vectors are estimated from blocks and DOIs between the RF and each of the GFs, respectively. With these motion vectors, object motions in space are compensated. Then, only the difference images between the 3-directionally motion-compensated RF and each of the GFs are applied to the NLUT for hologram calculation. Experimental results reveal that the average number of calculated object points and the average calculation time of the proposed method have been reduced compared to those of the conventional NLUT, TR-NLUT and MPEG-NLUT by 38.14%, 69.48%, and 67.41% and 35.30%, 66.39%, and 64.46%, respectively.

  2. Multiple sclerosis

    ... indwelling catheter Osteoporosis or thinning of the bones Pressure sores Side effects of medicines used to treat the ... Daily bowel care program Multiple sclerosis - discharge Preventing pressure ulcers Swallowing problems Images Multiple sclerosis MRI of the ...

  3. X-ray fluorescence holography and multiple-energy x-ray holography: A critical comparison of atomic images

    Len, P.M.; Gog, T.; Fadley, C.S.; Materlik, G.

    1997-01-01

    We compare x-ray fluorescence holography (XFH) and multiple-energy x-ray holography (MEXH), two techniques that have recently been used to obtain experimental three-dimensional atomic images. For single-energy holograms, these methods are equivalent by virtue of the optical reciprocity theorem. However, XFH can only record holographic information at the characteristic fluorescence energies of the emitting species, while MEXH can record holographic information at any energy above the fluorescent edge of the emitter, thus enabling the suppression of real-twin overlaps and other aberrations and artifacts in atomic images. copyright 1997 The American Physical Society

  4. MULTIPLE OBJECTS

    A. A. Bosov

    2015-04-01

    Full Text Available Purpose. The development of complicated techniques of production and management processes, information systems, computer science, applied objects of systems theory and others requires improvement of mathematical methods, new approaches for researches of application systems. And the variety and diversity of subject systems makes necessary the development of a model that generalizes the classical sets and their development – sets of sets. Multiple objects unlike sets are constructed by multiple structures and represented by the structure and content. The aim of the work is the analysis of multiple structures, generating multiple objects, the further development of operations on these objects in application systems. Methodology. To achieve the objectives of the researches, the structure of multiple objects represents as constructive trio, consisting of media, signatures and axiomatic. Multiple object is determined by the structure and content, as well as represented by hybrid superposition, composed of sets, multi-sets, ordered sets (lists and heterogeneous sets (sequences, corteges. Findings. In this paper we study the properties and characteristics of the components of hybrid multiple objects of complex systems, proposed assessments of their complexity, shown the rules of internal and external operations on objects of implementation. We introduce the relation of arbitrary order over multiple objects, we define the description of functions and display on objects of multiple structures. Originality.In this paper we consider the development of multiple structures, generating multiple objects.Practical value. The transition from the abstract to the subject of multiple structures requires the transformation of the system and multiple objects. Transformation involves three successive stages: specification (binding to the domain, interpretation (multiple sites and particularization (goals. The proposed describe systems approach based on hybrid sets

  5. Multiple sclerosis

    Grunwald, I.Q.; Kuehn, A.L.; Backens, M.; Papanagiotou, P.; Shariat, K.; Kostopoulos, P.

    2008-01-01

    Multiple sclerosis is the most common chronic inflammatory disease of myelin with interspersed lesions in the white matter of the central nervous system. Magnetic resonance imaging (MRI) plays a key role in the diagnosis and monitoring of white matter diseases. This article focuses on key findings in multiple sclerosis as detected by MRI. (orig.) [de

  6. Multiple homicides.

    Copeland, A R

    1989-09-01

    A study of multiple homicides or multiple deaths involving a solitary incident of violence by another individual was performed on the case files of the Office of the Medical Examiner of Metropolitan Dade County in Miami, Florida, during 1983-1987. A total of 107 multiple homicides were studied: 88 double, 17 triple, one quadruple, and one quintuple. The 236 victims were analyzed regarding age, race, sex, cause of death, toxicologic data, perpetrator, locale of the incident, and reason for the incident. This article compares this type of slaying with other types of homicide including those perpetrated by serial killers. Suggestions for future research in this field are offered.

  7. Multiple Sclerosis

    Multiple sclerosis (MS) is a nervous system disease that affects your brain and spinal cord. It damages the myelin sheath, the material that surrounds and protects your nerve cells. This damage slows down ...

  8. Multiple myeloma.

    Collins, Conor D

    2012-02-01

    Advances in the imaging and treatment of multiple myeloma have occurred over the past decade. This article summarises the current status and highlights how an understanding of both is necessary for optimum management.

  9. Multiple mononeuropathy

    ... with multiple mononeuropathy are prone to new nerve injuries at pressure points such as the knees and elbows. They should avoid putting pressure on these areas, for example, by not leaning on the elbows, crossing the knees, ...

  10. Multiple sclerosis and organic solvents

    Mortensen, J T; Brønnum-Hansen, Henrik; Rasmussen, K

    1998-01-01

    We investigated a possible causal relation between exposure to organic solvents in Danish workers (housepainters, typographers/printers, carpenters/cabinetmakers) and onset of multiple sclerosis. Data on men included in the Danish Multiple Sclerosis Register (3,241 men) were linked with data from......, and butchers. Over a follow-up period of 20 years, we observed no increase in the incidence of multiple sclerosis among men presumed to be exposed to organic solvents. It was not possible to obtain data on potential confounders, and the study design has some potential for selection bias. Nevertheless......, the study does not support existing hypotheses regarding an association between occupational exposure to organic solvents and multiple sclerosis....

  11. Experimental protocol for packaging and encrypting multiple data

    Barrera, John Fredy; Trejos, Sorayda; Tebaldi, Myrian; Torroba, Roberto

    2013-01-01

    We present a novel single optical packaging and encryption (SOPE) procedure for multiple inputs. This procedure is based on a merging of a 2f scheme with a digital holographic technique to achieve efficient handling of multiple data. Through the 2f system with a random phase mask attached in its input plane, and the holographic technique, we obtain each processed input. A posteriori filtering and repositioning protocol on each hologram followed by an addition of all processed data, allows storing these data to form a single package. The final package is digitally multiplied by a second random phase mask acting as an encryption mask. In this way, the final user receives only one encrypted information unit and a single key, instead of a conventional multiple-image collecting method and several keys. Processing of individual images is cast into an optimization problem. The proposed optimization aims to simplify the handling and recovery of images while packing all of them into a single unit. The decoding process does not have the usual cross-talk or noise problems involved in other methods, as filtering and repositioning precedes the encryption step. All data are recovered in just one step at the same time by applying a simple Fourier transform operation and the decoding key. The proposed protocol takes advantage of optical processing and the versatility of the digital format. Experiments have been conducted using a Mach–Zehnder interferometer. An application is subsequently demonstrated to illustrate the feasibility of the SOPE procedure. (paper)

  12. Multiple sclerosis

    Stenager, Egon; Stenager, E N; Knudsen, Lone

    1994-01-01

    In a cross-sectional study of 117 randomly selected patients (52 men, 65 women) with definite multiple sclerosis, it was found that 76 percent were married or cohabitant, 8 percent divorced. Social contacts remained unchanged for 70 percent, but outgoing social contacts were reduced for 45 percent......, need for structural changes in home and need for pension became greater with increasing physical handicap. No significant differences between gender were found. It is concluded that patients and relatives are under increased social strain, when multiple sclerosis progresses to a moderate handicap...

  13. Multiple Chemical Sensitivity

    Dantoft, Thomas Meinertz

    Multiple chemical sensitivity (MCS) is a chronic disorder characterized by reports of symptoms from various organ systems attributed by the individuals to exposure to common odors and airborne chemicals in doses far below those known to induce toxic effects. There exists a general lack of knowledge......, significantly reduced levels of IL-13 in the MCS group and no group differences in the allergen specific IgE measures. The differences were independent of factors such as sex, age, Body Mass Index, asthma, smoking, depression, anxiety and allergen-specific IgE. In conclusion, the study identified a distinct...

  14. Multiple myeloma

    Sohn, Jeong Ick; Ha, Choon Ho; Choi, Karp Shik

    1994-01-01

    Multiple myeloma is a malignant plasma cell tumor that is thought to originate proliferation of a single clone of abnormal plasma cell resulting production of a whole monoclonal paraprotein. The authors experienced a case of multiple myeloma with severe mandibular osteolytic lesions in 46-year-old female. As a result of careful analysis of clinical, radiological, histopathological features, and laboratory findings, we diagnosed it as multiple myeloma, and the following results were obtained. 1. Main clinical symptoms were intermittent dull pain on the mandibular body area, abnormal sensation of lip and pain due to the fracture on the right clavicle. 2. Laboratory findings revealed M-spike, reversed serum albumin-globulin ratio, markedly elevated ESR and hypercalcemia. 3. Radiographically, multiple osteolytic punched-out radiolucencies were evident on the skull, zygoma, jaw bones, ribs, clavicle and upper extremities. Enlarged liver and increased uptakes on the lesional sites in RN scan were also observed. 4. Histopathologically, markedly hypercellular marrow with sheets of plasmoblasts and megakaryocytes were also observed.

  15. Multiple sclerosis

    Stenager, E; Jensen, K

    1988-01-01

    Forty-two (12%) of a total of 366 patients with multiple sclerosis (MS) had psychiatric admissions. Of these, 34 (81%) had their first psychiatric admission in conjunction with or after the onset of MS. Classification by psychiatric diagnosis showed that there was a significant positive correlation...

  16. Multiple sclerosis

    Stenager, E; Knudsen, L; Jensen, K

    1991-01-01

    In a cross-sectional investigation of 116 patients with multiple sclerosis, the social and sparetime activities of the patient were assessed by both patient and his/her family. The assessments were correlated to physical disability which showed that particularly those who were moderately disabled...

  17. Multiple sclerosis

    Stenager, E; Jensen, K

    1990-01-01

    An investigation on the correlation between ability to read TV subtitles and the duration of visual evoked potential (VEP) latency in 14 patients with definite multiple sclerosis (MS), indicated that VEP latency in patients unable to read the TV subtitles was significantly delayed in comparison...

  18. Multiple sclerosis

    Stenager, E; Knudsen, L; Jensen, K

    1994-01-01

    In a cross-sectional study of 94 patients (42 males, 52 females) with definite multiple sclerosis (MS) in the age range 25-55 years, the correlation of neuropsychological tests with the ability to read TV-subtitles and with the use of sedatives is examined. A logistic regression analysis reveals...

  19. Multiple Sclerosis.

    Plummer, Nancy; Michael, Nancy, Ed.

    This module on multiple sclerosis is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first. The module goal and objectives are then…

  20. Parenting Multiples

    ... when your babies do. Though it can be hard to let go of the thousand other things you need to do, remember that your well-being is key to your ability to take care of your babies. What Problems Can Happen? It may be hard to tell multiple babies apart when they first ...