WorldWideScience

Sample records for ultrasound modulated light

  1. An electro-optic spatial light modulator for thermoelastic generation of programmably focused ultrasound

    Science.gov (United States)

    1984-12-01

    The concept proposed is an electro-optic technique that would make it possible to spatially modulate a high power pulsed laser beam to thermoelastically induce focused ultrasound in a test material. Being a purely electro-optic device, the modulator, and therefore the depth at which the acoustic focus occurs, can be programmed electronically at electronic speeds. If successful, it would become possible to scan ultrasound continuously in three dimensions within the component or structure under test.

  2. An algorithm for sensing venous oxygenation using ultrasound-modulated light enhanced by microbubbles

    Science.gov (United States)

    Honeysett, Jack E.; Stride, Eleanor; Deng, Jing; Leung, Terence S.

    2012-02-01

    Near-infrared spectroscopy (NIRS) can provide an estimate of the mean oxygen saturation in tissue. This technique is limited by optical scattering, which reduces the spatial resolution of the measurement, and by absorption, which makes the measurement insensitive to oxygenation changes in larger deep blood vessels relative to that in the superficial tissue. Acousto-optic (AO) techniques which combine focused ultrasound (US) with diffuse light have been shown to improve the spatial resolution as a result of US-modulation of the light signal, however this technique still suffers from low signal-to-noise when detecting a signal from regions of high optical absorption. Combining an US contrast agent with this hybrid technique has been proposed to amplify an AO signal. Microbubbles are a clinical contrast agent used in diagnostic US for their ability to resonate in a sound field: in this work we also make use of their optical scattering properties (modelled using Mie theory). A perturbation Monte Carlo (pMC) model of light transport in a highly absorbing blood vessel containing microbubbles surrounded by tissue is used to calculate the AO signal detected on the top surface of the tissue. An algorithm based on the modified Beer-Lambert law is derived which expresses intravenous oxygen saturation in terms of an AO signal. This is used to determine the oxygen saturation in the blood vessel from a dual wavelength microbubble-contrast AO measurement. Applying this algorithm to the simulation data shows that the venous oxygen saturation is accurately recovered, and this measurement is robust to changes in the oxygenation of the superficial tissue layer.

  3. Local inversions in ultrasound-modulated optical tomography

    International Nuclear Information System (INIS)

    Bal, Guillaume; Moskow, Shari

    2014-01-01

    Ultrasound-modulated optical tomography is a hybrid imaging modality that aims to combine the high contrast of optical waves with the high resolution of ultrasound. We follow the model of the influence of ultrasound modulation on the light intensity measurements developed in Bal and Schotland (2010 Phys. Rev. Lett. 104 043902). We present sufficient conditions ensuring that the absorption and diffusion coefficients modeling light propagation can locally be uniquely and stably reconstructed from the corresponding available information. We present an iterative procedure to solve such a problem based on the analysis of linear elliptic systems of redundant partial differential equations. (paper)

  4. Effect of modulated ultrasound parameters on ultrasound-induced thrombolysis

    International Nuclear Information System (INIS)

    Soltani, Azita; Volz, Kim R; Hansmann, Doulas R

    2008-01-01

    The potential of ultrasound to enhance enzyme-mediated thrombolysis by application of constant operating parameters (COP) has been widely demonstrated. In this study, the effect of ultrasound with modulated operating parameters (MOP) on enzyme-mediated thrombolysis was investigated. The MOP protocol was applied to an in vitro model of thrombolysis. The results were compared to a COP with the equivalent soft tissue thermal index (TIS) over the duration of ultrasound exposure of 30 min (p -2 ± 0.01 μm and 1.99 x 10 -2 ± 0.004 μm, respectively (p < 0.74). No signatures of inertial or stable cavitation were observed for either acoustic protocol. In conclusion, due to mechanisms other than cavitation, application of ultrasound with modulated operating parameters has the potential to significantly enhance the relative lysis enhancement compared to application of ultrasound with constant operating parameters.

  5. Reconstructions in ultrasound modulated optical tomography

    KAUST Repository

    Allmaras, Moritz; Bangerth, Wolfgang

    2011-01-01

    We introduce a mathematical model for ultrasound modulated optical tomography and present a simple reconstruction scheme for recovering the spatially varying optical absorption coefficient from scanning measurements with narrowly focused ultrasound signals. Computational results for this model show that the reconstruction of sharp features of the absorption coefficient is possible. A formal linearization of the model leads to an equation with a Fredholm operator, which explains the stability observed in our numerical experiments. © de Gruyter 2011.

  6. Synthetic focusing in ultrasound modulated tomography

    KAUST Repository

    Kuchment, Peter; Kunyansky, Leonid

    2010-01-01

    Several hybrid tomographic methods utilizing ultrasound modulation have been introduced lately. Success of these methods hinges on the feasibility of focusing ultrasound waves at an arbitrary point of interest. Such focusing, however, is difficult to achieve in practice. We thus propose a way to avoid the use of focused waves through what we call synthetic focusing, i.e. by reconstructing the would-be response to the focused modulation from the measurements corresponding to realistic unfocused waves. Examples of reconstructions from simulated data are provided. This non-technical paper describes only the general concept, while technical details will appear elsewhere. © 2010 American Institute of Mathematical Sciences.

  7. Synthetic focusing in ultrasound modulated tomography

    KAUST Repository

    Kuchment, Peter

    2010-09-01

    Several hybrid tomographic methods utilizing ultrasound modulation have been introduced lately. Success of these methods hinges on the feasibility of focusing ultrasound waves at an arbitrary point of interest. Such focusing, however, is difficult to achieve in practice. We thus propose a way to avoid the use of focused waves through what we call synthetic focusing, i.e. by reconstructing the would-be response to the focused modulation from the measurements corresponding to realistic unfocused waves. Examples of reconstructions from simulated data are provided. This non-technical paper describes only the general concept, while technical details will appear elsewhere. © 2010 American Institute of Mathematical Sciences.

  8. Ultrasound-based guidance of intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Fung, Albert Y.C.; Ayyangar, Komanduri M.; Djajaputra, David; Nehru, Ramasamy M.; Enke, Charles A.

    2006-01-01

    In ultrasound-guided intensity-modulated radiation therapy (IMRT) of prostate cancer, ultrasound imaging ascertains the anatomical position of patients during x-ray therapy delivery. The ultrasound transducers are made of piezoelectric ceramics. The same crystal is used for both ultrasound production and reception. Three-dimensional (3D) ultrasound devices capture and correlate series of 2-dimensional (2D) B-mode images. The transducers are often arranged in a convex array for focusing. Lower frequency reaches greater depth, but results in low resolution. For clear image, some gel is usually applied between the probe and the skin contact surface. For prostate positioning, axial and sagittal scans are performed, and the volume contours from computed tomography (CT) planning are superimposed on the ultrasound images obtained before radiation delivery at the linear accelerator. The planning volumes are then overlaid on the ultrasound images and adjusted until they match. The computer automatically deduces the offset necessary to move the patient so that the treatment area is in the correct location. The couch is translated as needed. The currently available commercial equipment can attain a positional accuracy of 1-2 mm. Commercial manufacturer designs differ in the detection of probe coordinates relative to the isocenter. Some use a position-sensing robotic arm, while others have infrared light-emitting diodes or pattern-recognition software with charge-couple-device cameras. Commissioning includes testing of image quality and positional accuracy. Ultrasound is mainly used in prostate positioning. Data for 7825 daily fractions of 234 prostate patients indicated average 3D inter-fractional displacement of about 7.8 mm. There was no perceivable trend of shift over time. Scatter plots showed slight prevalence toward superior-posterior directions. Uncertainties of ultrasound guidance included tissue inhomogeneities, speckle noise, probe pressure, and inter

  9. Light intensity modulation in phototherapy

    Science.gov (United States)

    Lukyanovich, P. A.; Zon, B. A.; Kunin, A. A.; Pankova, S. N.

    2015-04-01

    A hypothesis that blocking ATP synthesis is one of the main causes of the stimulating effect is considered based on analysis of the primary photostimulation mechanisms. The light radiation intensity modulation is substantiated and the estimates of such modulation parameters are made. An explanation is offered to the stimulation efficiency decrease phenomenon at the increase of the radiation dose during the therapy. The results of clinical research of the medical treatment in preventive dentistry are presented depending on the spectrum and parameters of the light flux modulation.

  10. Plasmonics light modulators

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Malureanu, Radu; Lavrinenko, Andrei

    Surface plasmon polaritons (SPPs) are waves propagating at the interface between a metal and a dielectric and, due to their tight confinement, may be used for nanoscale control of the light propagation. Thus, photonic integrated circuits can benefit from devices using SPPs because of their highly...

  11. Liquid crystal television spatial light modulators

    Science.gov (United States)

    Liu, Hua-Kuang; Chao, Tien-Hsin

    1989-01-01

    The spatial light modulation characteristics and capabilities of the liquid crystal television (LCTV) spatial light modulators (SLMs) are discussed. A comparison of Radio Shack, Epson, and Citizen LCTV SLMs is made.

  12. Breast Cancer Diagnosis Using Ultrasound and Diffusive Light

    National Research Council Canada - National Science Library

    Zhu, Quing

    2001-01-01

    The main goal of this study is to evaluate a novel imaging system and method that combines ultrasound with near infrared diffusive light to increase the sensitivity and specificity of breast cancer detection...

  13. Pulsed-ultrasound tagging of light in living tissues

    Science.gov (United States)

    Lev, Aner; Rubanov, E.; Pomerantz, Ami; Sfez, Bruno G.

    2004-07-01

    Ultrasound can be used in order to locally modulate, or tag, light in a turbid medium. This tagging process is made possible due to the extreme sensitivity of laser speckle distribution to minute changes within the medium. This hybrid technique presents several advantages compared to all-optical tomographic techniques, in that the image resolution is fixed by the ultrasound focus diameter. To our best knowledge, only in vitro experiments have been performed, either on tissue-like phantoms or meat. However a strong difference exists between these sample and living tissues. In living tissues, different kind of liquids flow through the capillaries, strongly reducing the sspeckle autocorrelation time. We have performed experiments on both mice and humans, showing that the autocorrelation time is much shorter than what was previously thought. We show however that it is possible to obtain signal with acceptable signal to noise ratio down to a few cm depth. We will also discuss the origin and characteristics of the speckle noise.

  14. Pulse shaping using a spatial light modulator

    CSIR Research Space (South Africa)

    Botha, N

    2009-07-01

    Full Text Available Femtosecond pulse shaping can be done by different kinds of pulse shapers, such as liquid crystal spatial light modulators (LC SLM), acousto optic modulators (AOM) and deformable and movable mirrors. A few applications where pulse shaping...

  15. Bactericidal effectiveness of modulated UV light

    International Nuclear Information System (INIS)

    Bank, H.L.; John, J.; Schmehl, M.K.; Dratch, R.J.

    1990-01-01

    Studies were designed to evaluate the effectiveness of pulsed modulated UV light waveforms for killing bacteria. Exposure of five strains of bacteria to the modulated information encoded in the light decreased the colony population from a confluent lawn to less than 20 colonies. However, approximately 2,000 colonies survived treatment with the same intensity and time of exposure to UV light lacking the modulated information

  16. Gates Auto Door Car With Lights Modulated

    OpenAIRE

    Lina Carolina; Luyung Dinani, Skom, MMSi

    2002-01-01

    In scientific writing wi ll be explained about automatic gates with modulated headlights, where to find the car lights were adjusted by the relative frequency darker because of this background that the author alleviate human task in performing daily activities by using an automatic gate with the car lights modulated.

  17. Mutually-modulated cross-gain modulation and slow light

    International Nuclear Information System (INIS)

    Sternklar, Shmuel; Sarid, Eyal; Wart, Maxim; Granot, Er'el

    2010-01-01

    The interaction of pump and Stokes light in a Brillouin medium, where both beams are modulated, can be utilized for controlling the group velocity of the amplified Stokes (or depleted pump). The dependence of the group velocity for this mutually-modulated cross-gain modulation (MMXGM) technique on the Brillouin gain parameter is studied. A sharp transition to slow light occurs in the G 1 α/β≈1 regime, where G 1 is the Brillouin gain parameter, and α and β are the pump and Stokes modulation indices, respectively. A comparison of MMXGM slow light to the Brillouin dispersion-based slow-light technique reveals the fundamental differences between them. The formation of higher harmonics of the modulation frequency is also discussed. The theoretical predictions are experimentally corroborated and potential applications in fiber-based sensing and interferometry are discussed

  18. Biphasically Modulating the Activity of Carboxypeptidase G2 with Ultrasound

    Directory of Open Access Journals (Sweden)

    Wanying Ma

    2017-07-01

    Full Text Available Background/Aims: Carboxypeptidase G2 (CPG2 has been used for cancer prodrug therapy to realize the targeted release of active drugs, but there yet lacks a means to modulate the CPG2 activity. Here ultrasound was used to modulate the CPG2 activity. Methods: The activity of insonated CPG2 was determined, and then underlying biochemical (i.e., monomer, dimer and conformation and ultrasonic (i.e., heat and cavitation mechanisms were explored. Results: Ultrasound (1.0 MHz increased or decreased the enzymatic activity; the activity decreased as zero- or first-order kinetics, depending on the intensity. L1 (10 W/cm2 for 200 s improved the activity via increasing the specific activity. L2 or L3 (20 W/cm2 for 1200 or 3000 s decreased the activity via disassembling the dimer, degrading the monomer, inducing glycosylation, transforming conformation and decreasing the specific activity. An increase or a slight decrease of activity attributable to 10 W/cm2 was reversible, but the activity decrease due to 20 W/cm2 was irreversible. The enzymatic modulation was realized via cavitation. Conclusion: Ultrasound can biphasically modulate the CPG2 activity, and can be employed in the CPG2-prodrug therapy to adjust the release and moles of active drugs.

  19. Pulsed ultrasound modulated optical tomography with harmonic lock-in holography detection.

    Science.gov (United States)

    Ruan, Haowen; Mather, Melissa L; Morgan, Stephen P

    2013-07-01

    A method that uses digital heterodyne holography reconstruction to extract scattered light modulated by a single-cycle ultrasound (US) burst is demonstrated and analyzed. An US burst is used to shift the pulsed laser frequency by a series of discrete harmonic frequencies which are then locked on a CCD. The analysis demonstrates that the unmodulated light's contribution to the detected signal can be canceled by appropriate selection of the pulse repetition frequency. It is also shown that the modulated signal can be maximized by selecting a pulse sequence which consists of a pulse followed by its inverted counterpart. The system is used to image a 12 mm thick chicken breast with 2 mm wide optically absorbing objects embedded at the midplane. Furthermore, the method can be revised to detect the nonlinear US modulated signal by locking at the second harmonic US frequency.

  20. Improving the signal-to-noise ratio in ultrasound-modulated optical tomography by a lock-in amplifier

    Science.gov (United States)

    Zhu, Lili; Wu, Jingping; Lin, Guimin; Hu, Liangjun; Li, Hui

    2016-10-01

    With high spatial resolution of ultrasonic location and high sensitivity of optical detection, ultrasound-modulated optical tomography (UOT) is a promising noninvasive biological tissue imaging technology. In biological tissue, the ultrasound-modulated light signals are very weak and are overwhelmed by the strong unmodulated light signals. It is a difficulty and key to efficiently pick out the weak modulated light from strong unmodulated light in UOT. Under the effect of an ultrasonic field, the scattering light intensity presents a periodic variation as the ultrasonic frequency changes. So the modulated light signals would be escape from the high unmodulated light signals, when the modulated light signals and the ultrasonic signal are processed cross correlation operation by a lock-in amplifier and without a chopper. Experimental results indicated that the signal-to-noise ratio of UOT is significantly improved by a lock-in amplifier, and the higher the repetition frequency of pulsed ultrasonic wave, the better the signal-to-noise ratio of UOT.

  1. Smart lighting using a liquid crystal modulator

    Science.gov (United States)

    Baril, Alexandre; Thibault, Simon; Galstian, Tigran

    2017-08-01

    Now that LEDs have massively invaded the illumination market, a clear trend has emerged for more efficient and targeted lighting. The project described here is at the leading edge of the trend and aims at developing an evaluation board to test smart lighting applications. This is made possible thanks to a new liquid crystal light modulator recently developed for broadening LED light beams. The modulator is controlled by electrical signals and is characterized by a linear working zone. This feature allows the implementation of a closed loop control with a sensor feedback. This project shows that the use of computer vision is a promising opportunity for cheap closed loop control. The developed evaluation board integrates the liquid crystal modulator, a webcam, a LED light source and all the required electronics to implement a closed loop control with a computer vision algorithm.

  2. Manipulating light with strongly modulated photonic crystals

    International Nuclear Information System (INIS)

    Notomi, Masaya

    2010-01-01

    Recently, strongly modulated photonic crystals, fabricated by the state-of-the-art semiconductor nanofabrication process, have realized various novel optical properties. This paper describes the way in which they differ from other optical media, and clarifies what they can do. In particular, three important issues are considered: light confinement, frequency dispersion and spatial dispersion. First, I describe the latest status and impact of ultra-strong light confinement in a wavelength-cubic volume achieved in photonic crystals. Second, the extreme reduction in the speed of light is reported, which was achieved as a result of frequency dispersion management. Third, strange negative refraction in photonic crystals is introduced, which results from their unique spatial dispersion, and it is clarified how this leads to perfect imaging. The last two sections are devoted to applications of these novel properties. First, I report the fact that strong light confinement and huge light-matter interaction enhancement make strongly modulated photonic crystals promising for on-chip all-optical processing, and present several examples including all-optical switches/memories and optical logics. As a second application, it is shown that the strong light confinement and slow light in strongly modulated photonic crystals enable the adiabatic tuning of light, which leads to various novel ways of controlling light, such as adiabatic frequency conversion, efficient optomechanics systems, photon memories and photons pinning.

  3. Modules to enhance smart lighting education

    Science.gov (United States)

    Bunch, Robert M.; Joenathan, Charles; Connor, Kenneth; Chouikha, Mohamed

    2012-10-01

    Over the past several years there has been a rapid advancement in solid state lighting applications brought on by the development of high efficiency light emitting diodes. Development of lighting devices, systems and products that meet the demands of the future lighting marketplace requires workers from many disciplines including engineers, scientists, designers and architects. The National Science Foundation has recognized this fact and established the Smart Lighting Engineering Research Center that promotes research leading to smart lighting systems, partners with industry to enhance innovation and educates a diverse, world-class workforce. The lead institution is Rensselaer Polytechnic Institute with core partners Boston University and The University of New Mexico. Outreach partners include Howard University, Morgan State University, and Rose-Hulman Institute of Technology. Because of the multidisciplinary nature of advanced smart lighting systems workers often have little or no formal education in basic optics, lighting and illumination. This paper describes the initial stages of the development of self-contained and universally applicable educational modules that target essential optics topics needed for lighting applications. The modules are intended to be easily incorporated into new and existing courses by a variety of educators and/or to be used in a series of stand-alone, asynchronous training exercises by new graduate students. The ultimate goal of this effort is to produce resources such as video lectures, video presentations of students-teaching-students, classroom activities, assessment tools, student research projects and laboratories integrated into learning modules. Sample modules and resources will be highlighted. Other outreach activities such as plans for coursework, undergraduate research, design projects, and high school enrichment programs will be discussed.

  4. Light Microscopy Module (LMM)-Emulator

    Science.gov (United States)

    Levine, Howard G.; Smith, Trent M.; Richards, Stephanie E.

    2016-01-01

    The Light Microscopy Module (LMM) is a microscope facility developed at Glenn Research Center (GRC) that provides researchers with powerful imaging capability onboard the International Space Station (ISS). LMM has the ability to have its hardware recongured on-orbit to accommodate a wide variety of investigations, with the capability of remotely acquiring and downloading digital images across multiple levels of magnication.

  5. Visible light communications modulation and signal processing

    CERN Document Server

    Wang, Zhaocheng; Huang, Wei; Xu, Zhengyuan

    2018-01-01

    This informative new book on state-of-the-art visible light communication (VLC) provides, for the first time, a systematical and advanced treatment of modulation and signal processing for VLC. Visible Light Communications: Modulation and Signal Processing offers a practical guide to designing VLC, linking academic research with commercial applications. In recent years, VLC has attracted attention from academia and industry since it has many advantages over the traditional radio frequency, including wide unregulated bandwidth, high security, and low cost. It is a promising complementary technique in 5G and beyond wireless communications, especially in indoor applications. However, lighting constraints have not been fully considered in the open literature when considering VLC system design, and its importance has been underestimated. That’s why this book—written by a team of experts with both academic research experience and industrial development experience in the field—is so welcome. To help readers u...

  6. Spatial light modulation for mode conditioning

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    We demonstrate patented techniques for generating tuneable complex field distributions for controllable coupling to high-order guided modes of micro-structured fibres. The optical Fourier transform of binary phase-only patterns which are encoded on a computer-controlled spatial light modulator......, generates complex field distributions for selective launching of a desired mode. Both the amplitude and the phase of the programmable fields are modulated by straightforward and fast adjustments of simple pre-defined binary phase-only diffractive patterns. Experiments demonstrate tuneable coupling...

  7. Planar Silicon Optical Waveguide Light Modulators

    DEFF Research Database (Denmark)

    Leistiko, Otto; Bak, H.

    1994-01-01

    that values in the nanosecond region should be possible, however, the measured values are high, 20 microseconds, due to the large area of the injector junctions, 1× 10¿2 cm2, and the limitations imposed by the detection circuit. The modulating properties of these devices are impressive, measurements......The results of an experimental investigation of a new type of optical waveguide based on planar technology in which the liglht guiding and modulation are achieved by exploiting free carrier effects in silicon are presented. Light is guided between the n+ substrate and two p+ regions, which also...... serve as carrier injectors for controling absorption. Light confinement of single mode devices is good, giving spot sizes of 9 ¿m FWHM. Insertion loss measurements indicate that the absorption losses for these waveguides are extremely low, less 1 dB/cm. Estimates of the switching speed indicate...

  8. Enhanced Interferometry with Programmable Spatial Light Modulator

    Science.gov (United States)

    2010-06-07

    Interferometry, Spatial Light Modulator, Surface Accuracy, Optics, Mirror, Zernike , Freeform Optics, Null Testing, Hartman, Wavefront 16. SECURITY...S L M P ix e l- c a m Tilted Flat Mirror L a s e r PV. ± 3.4 λ -Tilt by the flat mirror, ~7 waves ~ 14 fringes Interferogram 3D view (Various...Interferogram ( 3D view) x- profile y- profile (Various waveplates and telescopes not shown) SLM can compensate tilted wavefronts with an accuracy of

  9. Light induced modulation instability of surfaces under intense illumination

    KAUST Repository

    Burlakov, V. M.; Foulds, Ian G.; Goriely, A.

    2013-01-01

    heated by radiation. Periodic heating is due to focusing-defocusing effects caused by the initial surface modulation. The surface modulation has a period longer than the excitation wavelength and does not require coherent light source. Therefore

  10. Use of modulated excitation signals in ultrasound. Part I: Basic concepts and expected benefits

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Jensen, Jørgen Arendt

    2005-01-01

    This paper, the first from a series of three papers on the application of coded excitation signals in medical ultrasound, discusses the basic principles and ultrasound-related problems of pulse compression. The concepts of signal modulation and matched filtering are given, and a simple model...... of attenuation relates the matched filter response with the ambiguity function, known from radar. Based on this analysis and the properties of the ambiguity function, the selection of coded waveforms suitable for ultrasound imaging is discussed. It is shown that linear frequency modulation (FM) signals have...... that in the case of linear FM signals, a SNR improvement of 12 to 18 dB can be expected for large imaging depths in attenuating media, without any depth-dependent filter compensation. In contrast, nonlinear FM modulation and binary codes are shown to give a SNR improvement of only 4 to 9 dB when processed...

  11. A 10 MHz Bandwidth Continuous-Time Delta-Sigma Modulator for Portable Ultrasound Scanners

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Jørgensen, Ivan Harald Holger; Bruun, Erik

    2016-01-01

    comparator and a pull-down clocked latch. The feedback signal is generated with voltage DACs based on transmission gates. Using this implementation, a small and low-power solution required for portable ultrasound scanner applications is achieved. The modulator has a bandwidth of 10 MHz with an oversampling......A fourth-order 1-bit continuous-time delta-sigma modulator designed in a 65 nm process for portable ultrasound scanners is presented in this paper. The loop filter consists of RCintegrators, with programmable capacitor arrays and resistors, and the quantizer is implemented with a high-speed clocked...

  12. Thermal management of solid state lighting module

    NARCIS (Netherlands)

    Ye, H.

    2014-01-01

    Solid-State Lighting (SSL), powered by Light-Emitting Diodes (LEDs), is an energy-efficient technology for lighting systems. In contrast to incandescent lights which obtain high efficiency at high temperatures, the highest efficiency of LEDs is reached at low temperatures. The thermal management in

  13. Light and ultrasound activated microbubbles around gold nanorods for photoacoustic microsurgery

    Science.gov (United States)

    Cavigli, Lucia; Centi, Sonia; Lai, Sarah; Borri, Claudia; Micheletti, Filippo; Tortoli, Paolo; Panettieri, Ilaria; Streit, Ingolf; Rossi, Francesca; Ratto, Fulvio; Pini, Roberto

    2017-07-01

    Photoacoustic imaging and microsurgery have recently attracted attention for applications in oncology. Here, we present a versatile set-up to trigger vapor microbubbles around plasmonic nanoparticles by a combined light-ultrasound excitation. This system enables the detection and parametrization of bubbles as a function of several variables, such us optical fluence, ultrasound intensity, nanoparticles concentration, thus providing useful directions to the development of new strategies for treatments based on optical cavitation.

  14. Ultrasound

    Science.gov (United States)

    Ultrasound is a useful procedure for monitoring the baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two-dimensional image of the baby while inside the mother's ...

  15. Modulations in the light of the firefly

    Indian Academy of Sciences (India)

    The amplitude of the continuous train of triangular pulses is apparently altered in accordance with the instantaneous values of a hypothetical signal, which exhibits pulse amplitude modulation (PAM). In addition to sampling in amplitude, this scheme apparently provides sampling in time, representing pulse width modulation ...

  16. Performance comparison of binary modulation schemes for visible light communication

    KAUST Repository

    Park, Kihong

    2015-09-11

    In this paper, we investigate the power spectral density of several binary modulation schemes including variable on-off keying, variable pulse position modulation, and pulse dual slope modulation which were previously proposed for visible light communication with dimming control. We also propose a novel slope-based modulation called differential chip slope modulation (DCSM) and develop a chip-based hard-decision receiver to demodulate the resulting signal, detect the chip sequence, and decode the input bit sequence. We show that the DCSM scheme can exploit spectrum density more efficiently than the reference schemes while providing an error rate performance comparable to them. © 2015 IEEE.

  17. System Level Design of a Continuous-Time Delta-Sigma Modulator for Portable Ultrasound Scanners

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Færch, Kjartan; Jørgensen, Ivan Harald Holger

    2015-01-01

    In this paper the system level design of a continuous-time ∆Σ modulator for portable ultrasound scanners is presented. The overall required signal-to-noise ratio (SNR) is derived to be 42 dB and the sampling frequency used is 320 MHz for an oversampling ratio of 16. In order to match these requir......, based on high-level VerilogA simulations, the performance of the ∆Σ modulator versus various block performance parameters is presented as trade-off curves. Based on these results, the block specifications are derived.......In this paper the system level design of a continuous-time ∆Σ modulator for portable ultrasound scanners is presented. The overall required signal-to-noise ratio (SNR) is derived to be 42 dB and the sampling frequency used is 320 MHz for an oversampling ratio of 16. In order to match...

  18. Beam-quality measurements using a spatial light modulator

    CSIR Research Space (South Africa)

    Schulze, C

    2012-11-01

    Full Text Available We present a fast and easy technique for measuring the beam propagation ratio, M2, of laser beams using a spatial light modulator. Our technique is based on digitally simulating the free-space propagation of light, thus eliminating the need...

  19. Exploration of external light trapping for photovoltaic modules

    NARCIS (Netherlands)

    van Dijk, L.; van de Groep, J.; Di Vece, M.; Schropp, R.E.I.

    2016-01-01

    The reflection of incident sunlight by photovoltaic modules prevents them from reaching their theoretical energy conversion limit. We explore the effectiveness of a universal external light trap that can tackle this reflection loss. A unique feature of external light traps is their capability to

  20. Light induced modulation instability of surfaces under intense illumination

    KAUST Repository

    Burlakov, V. M.

    2013-12-17

    We show that a flat surface of a polymer in rubber state illuminated with intense electromagnetic radiation is unstable with respect to periodic modulation. Initial periodic perturbation is amplified due to periodic thermal expansion of the material heated by radiation. Periodic heating is due to focusing-defocusing effects caused by the initial surface modulation. The surface modulation has a period longer than the excitation wavelength and does not require coherent light source. Therefore, it is not related to the well-known laser induced periodic structures on polymer surfaces but may contribute to their formation and to other phenomena of light-matter interaction.

  1. Cost effective flat plate photovoltaic modules using light trapping

    Science.gov (United States)

    Bain, C. N.; Gordon, B. A.; Knasel, T. M.; Malinowski, R. L.

    1981-01-01

    Work in optical trapping in 'thick films' is described to form a design guide for photovoltaic engineers. A thick optical film can trap light by diffusive reflection and total internal reflection. Light can be propagated reasonably long distances compared with layer thicknesses by this technique. This makes it possible to conduct light from inter-cell and intra-cell areas now not used in photovoltaic modules onto active cell areas.

  2. Laser trapping and spatial light modulators

    DEFF Research Database (Denmark)

    Glückstad, Jesper

    2012-01-01

    INVITED: Robotics at the macro-scale typically uses light for carrying information in machine vision for monitoring and feedback in intelligent robotic guidance systems. With light’s miniscule momentum, shrinking robots down to the micro-scale regime creates opportunities for exploiting optical f...

  3. Ultrasound

    Science.gov (United States)

    ... completed. Young children may need additional preparation. When scheduling an ultrasound for yourself or your child, ask ... of Privacy Practices Notice of Nondiscrimination Manage Cookies Advertising Mayo Clinic is a not-for-profit organization ...

  4. Ultrasound

    Science.gov (United States)

    ... reflect off body structures. A computer receives the waves and uses them to create a picture. Unlike with an x-ray or CT scan, this test does not use ionizing radiation. The test is done in the ultrasound ...

  5. Light Modulates Leptin and Ghrelin in Sleep-Restricted Adults

    Directory of Open Access Journals (Sweden)

    Mariana G. Figueiro

    2012-01-01

    Full Text Available Acute and chronic sleep restrictions cause a reduction in leptin and an increase in ghrelin, both of which are associated with hunger. Given that light/dark patterns are closely tied to sleep/wake patterns, we compared, in a within-subjects study, the impact of morning light exposures (60 lux of 633-nm [red], 532-nm [green], or 475-nm [blue] lights to dim light exposures on leptin and ghrelin concentrations after subjects experienced 5 consecutive days of both an 8-hour (baseline and a 5-hour sleep-restricted schedule. In morning dim light, 5-hour sleep restriction significantly reduced leptin concentrations compared to the baseline, 8-hour sleep/dim-light condition (1,32 = 2.9; =0.007. Compared to the 5-hour sleep/dim-light condition, the red, green, and blue morning light exposures significantly increased leptin concentrations (1,32 = 5.7; <0.0001, 1,32 = 3.6; =0.001, and 1,32 = 3.0; =0.005, resp.. Morning red light and green light exposures significantly decreased ghrelin concentrations (1,32 = 3.3; <0.003 and 1,32 = 2.2; =0.04, resp., but morning blue light exposures did not. This study is the first to demonstrate that morning light can modulate leptin and ghrelin concentrations, which could have an impact on reducing hunger that accompanies sleep deprivation.

  6. Shaping and detecting mid-IR light with a spatial light modulator

    CSIR Research Space (South Africa)

    Maweza, Elijah L

    2016-10-01

    Full Text Available modulator Maweza, Elijah L Gailele, Lucas M Strauss, Hencharl J Litvin, Ihar Forbes, Andrew Dudley, Angela L ABSTRACT: We demonstrate the operation and calibration of a spatial light modulator in the mid-IR region by creating and measuring...

  7. Origin of Infrared Light Modulation in Reflectance-Mode Photoplethysmography.

    Directory of Open Access Journals (Sweden)

    Igor S Sidorov

    Full Text Available We recently pointed out the important role of dermis deformation by pulsating arterial pressure in the formation of a photoplethysmographic signal at green light. The aim of this study was to explore the role of this novel finding in near-infrared (NIR light. A light-emitting diode (LED-based imaging photoplethysmography (IPPG system was used to detect spatial distribution of blood pulsations under frame-to-frame switching green and NIR illumination in the palms of 34 healthy individuals. We observed a significant increase of light-intensity modulation at the heartbeat frequency for both illuminating wavelengths after a palm was contacted with a glass plate. Strong positive correlation between data measured at green and NIR light was found, suggesting that the same signal was read independently from the depth of penetration. Analysis of the data shows that an essential part of remitted NIR light is modulated in time as a result of elastic deformations of dermis caused by variable blood pressure in the arteries. Our observations suggest that in contrast with the classical model, photoplethysmographic waveform originates from the modulation of the density of capillaries caused by the variable pressure applied to the skin from large blood vessels. Particularly, beat-to-beat transmural pressure in arteries compresses/decompresses the dermis and deforms its connective-tissue components, thus affecting the distance between the capillaries, which results in the modulation of absorption and scattering coefficients of both green and NIR light. These findings are important for the correct interpretation of this widely used medical technique, which may have novel applications in diagnosis and treatment monitoring of aging and skin diseases.

  8. Phototropin 1 and dim-blue light modulate the red light de-etiolation response.

    Science.gov (United States)

    Wang, Yihai; M Folta, Kevin

    2014-01-01

    Light signals regulate seedling morphological changes during de-etiolation through the coordinated actions of multiple light-sensing pathways. Previously we have shown that red-light-induced hypocotyl growth inhibition can be reversed by addition of dim blue light through the action of phototropin 1 (phot1). Here we further examine the fluence-rate relationships of this blue light effect in short-term (hours) and long-term (days) hypocotyl growth assays. The red stem-growth inhibition and blue promotion is a low-fluence rate response, and blue light delays or attenuates both the red light and far-red light responses. These de-etiolation responses include blue light reversal of red or far-red induced apical hook opening. This response also requires phot1. Cryptochromes (cry1 and cry2) are activated by higher blue light fluence-rates and override phot1's influence on hypocotyl growth promotion. Exogenous application of auxin transport inhibitor naphthylphthalamic acid abolished the blue light stem growth promotion in both hypocotyl growth and hook opening. Results from the genetic tests of this blue light effect in auxin transporter mutants, as well as phytochrome kinase substrate mutants indicated that aux1 may play a role in blue light reversal of red light response. Together, the phot1-mediated adjustment of phytochrome-regulated photomorphogenic events is most robust in dim blue light conditions and is likely modulated by auxin transport through its transporters.

  9. Optimal Fisher Discriminant Ratio for an Arbitrary Spatial Light Modulator

    Science.gov (United States)

    Juday, Richard D.

    1999-01-01

    Optimizing the Fisher ratio is well established in statistical pattern recognition as a means of discriminating between classes. I show how to optimize that ratio for optical correlation intensity by choice of filter on an arbitrary spatial light modulator (SLM). I include the case of additive noise of known power spectral density.

  10. Creation and detection of optical modes with spatial light modulators

    CSIR Research Space (South Africa)

    Forbes, A

    2016-06-01

    Full Text Available (1979). 24. J. A. Davis, K. O. Valade´z, and D. M. Cottrell, “Encoding amplitude and phase information onto a binary phase-only spatial light modulator,” Appl. Opt. 42, 2003–2008 (2003). 25. E. Bolduc, N. Bent, E. Santamato, E. Karimi, and R. W. Boyd...

  11. Absolute rate measurement by light modulation - ESR technique

    Energy Technology Data Exchange (ETDEWEB)

    Choo, K Y; Gaspar, P P

    1977-01-01

    A rate constant is deduced for the reaction of tert-butoxy radicals and trimethylsilane from the measurement of the phase shift between the modulated light source and the ESR signal of trimethylsilyl radical. The rate constant was found to be 3 x 10/sup -2/M/sup -1/. sec/sup -1/ at -50/sup 0/C.

  12. Quantification of high-power ultrasound induced damage on potato starch granules using light microscopy.

    Science.gov (United States)

    Zuo, Yue Yue J; Hébraud, Pascal; Hemar, Yacine; Ashokkumar, Muthupandian

    2012-05-01

    A simple light microscopic technique was developed in order to quantify the damage inflicted by high-power low-frequency ultrasound (0-160 W, 20 kHz) treatment on potato starch granules in aqueous dispersions. The surface properties of the starch granules were modified using ethanol and SDS washing methods, which are known to displace proteins and lipids from the surface of the starch granules. The study showed that in the case of normal and ethanol-washed potato starch dispersions, two linear regions were observed. The number of defects first increased linearly with an increase in ultrasound power up to a threshold level. This was then followed by another linear dependence of the number of defects on the ultrasound power. The power threshold where the change-over occurred was higher for the ethanol-washed potato dispersions compared to non-washed potato dispersions. In the case of SDS-washed potato starch, although the increase in defects was linear with the ultrasound power, the power threshold for a second linear region was not observed. These results are discussed in terms of the different possible mechanisms of cavitation induced-damage (hydrodynamic shear stresses and micro-jetting) and by taking into account the hydrophobicity of the starch granule surface. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. A tele-operated mobile ultrasound scanner using a light-weight robot.

    Science.gov (United States)

    Delgorge, Cécile; Courrèges, Fabien; Al Bassit, Lama; Novales, Cyril; Rosenberger, Christophe; Smith-Guerin, Natalie; Brù, Concepció; Gilabert, Rosa; Vannoni, Maurizio; Poisson, Gérard; Vieyres, Pierre

    2005-03-01

    This paper presents a new tele-operated robotic chain for real-time ultrasound image acquisition and medical diagnosis. This system has been developed in the frame of the Mobile Tele-Echography Using an Ultralight Robot European Project. A light-weight six degrees-of-freedom serial robot, with a remote center of motion, has been specially designed for this application. It holds and moves a real probe on a distant patient according to the expert gesture and permits an image acquisition using a standard ultrasound device. The combination of mechanical structure choice for the robot and dedicated control law, particularly nearby the singular configuration allows a good path following and a robotized gesture accuracy. The choice of compression techniques for image transmission enables a compromise between flow and quality. These combined approaches, for robotics and image processing, enable the medical specialist to better control the remote ultrasound probe holder system and to receive stable and good quality ultrasound images to make a diagnosis via any type of communication link from terrestrial to satellite. Clinical tests have been performed since April 2003. They used both satellite or Integrated Services Digital Network lines with a theoretical bandwidth of 384 Kb/s. They showed the tele-echography system helped to identify 66% of lesions and 83% of symptomatic pathologies.

  14. Installation of the light tight cover for the SSD modules (the modules are behind the aluminium plate). The silicon sensors are sensitive to light tight, so ambient light will increase the noise and may even damage them.

    CERN Multimedia

    Nooren, G.

    2004-01-01

    Installation of the light tight cover for the SSD modules (the modules are behind the aluminium plate). The silicon sensors are sensitive to light tight , so ambient light will increase the noise and may even damage them.

  15. Light intensity modulates corneal power and refraction in the chick eye exposed to continuous light.

    Science.gov (United States)

    Cohen, Yuval; Belkin, Michael; Yehezkel, Oren; Avni, Isaac; Polat, Uri

    2008-09-01

    Continuous exposure of chicks to light was shown to result in severe hyperopia, accompanied by anterior segment changes, such as severe corneal flattening. Since rearing chicks in complete darkness results only in mild hyperopia and minor changes in corneal curvature, we hypothesized that light intensity may play a role in the development of refractive changes under continuous light illumination. To test this hypothesis, we examined the effects of rearing chicks under various continuous light intensities. More specifically, we investigated the refractive parameters of the chicks' eyes, and avoided light cycling effects on ocular development. To this end, thirty-eight chicks were reared under 24-h incandescent illumination, at three different light intensities: 10,000 lux (n=13), 500 lux (n=12), and 50 lux (n=13). Their eyes underwent repeated retinoscopy, keratometry, and ultrasound biometry, as well as caliper measurements of enucleated eyes. Both refraction and corneal refractive power were found to be correlated with light intensity. On day 90 after hatching, exposure to light intensities of 10,000, 500, and 50 lux resulted in hyperopia of +11.97+/-3.7 (mean+/-SD) +7.9+/-4.08 and +0.63+/-3.61 diopters (D), respectively. Under those intensities, corneal refractive power was 46.10+/-3.62, 49.72+/-4.16, and 56.88+/-4.92D, respectively. Axial length did not differ significantly among the groups. The vitreous chamber was significantly deeper in the high than in the low-intensity groups. Thus, during the early life of chicks exposed to continuous lighting, light intensity affects the vitreous chamber depth as well as the anterior segment parameters, most notably the cornea. The higher the intensity, the more severe was the corneal flattening observed and the hyperopia that developed, whereas continuous illumination at low intensities resulted in emmetropia. Thus, light intensity is an important factor that should be taken into account when studying refractive

  16. Designing Non-linear Frequency Modulated Signals For Medical Ultrasound Imaging

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jensen, Jørgen Arendt

    2006-01-01

    In this paper a new method for designing non-linear frequency modulated (NLFM) waveforms for ultrasound imaging is proposed. The objective is to control the amplitude spectrum of the designed waveform and still keep a constant transmit amplitude, so that the transmitted energy is maximized....... The signal-to-noise-ratio can in this way be optimized. The waveform design is based on least squares optimization. A desired amplitude spectrum is chosen, hereafter the phase spectrum is chosen, so that the instantaneous frequency takes on the form of a third order polynomial. The finite energy waveform...

  17. Subcarrier intensity modulation for MIMO visible light communications

    Science.gov (United States)

    Celik, Yasin; Akan, Aydin

    2018-04-01

    In this paper, subcarrier intensity modulation (SIM) is investigated for multiple-input multiple-output (MIMO) visible light communication (VLC) systems. A new modulation scheme called DC-aid SIM (DCA-SIM) is proposed for the spatial modulation (SM) transmission plan. Then, DCA-SIM is extended for multiple subcarrier case which is called DC-aid Multiple Subcarrier Modulation (DCA-MSM). Bit error rate (BER) performances of the considered system are analyzed for different MIMO schemes. The power efficiencies of DCA-SIM and DCA-MSM are shown in correlated MIMO VLC channels. The upper bound BER performances of the proposed models are obtained analytically for PSK and QAM modulation types in order to validate the simulation results. Additionally, the effect of power imbalance method on the performance of SIM is studied and remarkable power gains are obtained compared to the non-power imbalanced cases. In this work, Pulse amplitude modulation (PAM) and MSM-Index are used as benchmarks for single carrier and multiple carrier cases, respectively. And the results show that the proposed schemes outperform PAM and MSM-Index for considered single carrier and multiple carrier communication scenarios.

  18. Flicker in a twisted nematic spatial light modulator

    Science.gov (United States)

    Calderón-Hermosillo, Yuliana; García-Márquez, Jorge; Espinosa-Luna, Rafael; Ochoa, Noé Alcalá; López, Víctor; Aguilar, Alberto; Noé-Arias, Enrique; Alayli, Yasser

    2013-06-01

    Liquid Crystal on Silicon (LCoS) Spatial Light Modulators (SLM) are widely used for their capability to control beams howbeit fluctuations in phase and amplitude. It is then necessary to understand the negative effects of these fluctuations, also known as flicker, and the means to mitigate them. The flicker is observed either as high frequency variations of polarization, attenuation or high phase fluctuations on the wave front modulated by the LCoS device. Here, we compare the flicker behavior in a twisted nematic (TN) LCoS-SLM for different polarization schemes and temperatures. The quantitative evaluation shows that flicker is effectively reduced only by chilling the LCoS panel to temperatures just below 0 °C but, the LCoS modulation capability is also affected.

  19. Speckless head-up display on two spatial light modulators

    Science.gov (United States)

    Siemion, Andrzej; Ducin, Izabela; Kakarenko, Karol; Makowski, Michał; Siemion, Agnieszka; Suszek, Jarosław; Sypek, Maciej; Wojnowski, Dariusz; Jaroszewicz, Zbigniew; Kołodziejczyk, Andrzej

    2010-12-01

    There is a continuous demand for the computer generated holograms to give an almost perfect reconstruction with a reasonable cost of manufacturing. One method of improving the image quality is to illuminate a Fourier hologram with a quasi-random, but well known, light field phase distribution. It can be achieved with a lithographically produced phase mask. Up to date, the implementation of the lithographic technique is relatively complex and time and money consuming, which is why we have decided to use two Spatial Light Modulators (SLM). For the correctly adjusted light polarization a SLM acts as a pure phase modulator with 256 adjustable phase levels between 0 and 2π. The two modulators give us an opportunity to use the whole surface of the device and to reduce the size of the experimental system. The optical system with one SLM can also be used but it requires dividing the active surface into halves (one for the Fourier hologram and the second for the quasi-random diffuser), which implies a more complicated optical setup. A larger surface allows to display three Fourier holograms, each for one primary colour: red, green and blue. This allows to reconstruct almost noiseless colourful dynamic images. In this work we present the results of numerical simulations of image reconstructions with the use of two SLM displays.

  20. Monitoring of transient cavitation induced by ultrasound and intense pulsed light in presence of gold nanoparticles.

    Science.gov (United States)

    Sazgarnia, Ameneh; Shanei, Ahmad; Shanei, Mohammad Mahdi

    2014-01-01

    One of the most important challenges in medical treatment is invention of a minimally invasive approach in order to induce lethal damages to cancer cells. Application of high intensity focused ultrasound can be beneficial to achieve this goal via the cavitation process. Existence of the particles and vapor in a liquid decreases the ultrasonic intensity threshold required for cavitation onset. In this study, synergism of intense pulsed light (IPL) and gold nanoparticles (GNPs) has been investigated as a means of providing nucleation sites for acoustic cavitation. Several approaches have been reported with the aim of cavitation monitoring. We conducted the experiments on the basis of sonochemiluminescence (SCL) and chemical dosimetric methods. The acoustic cavitation activity was investigated by determining the integrated SCL signal acquired over polyacrylamide gel phantoms containing luminol in the presence and absence of GNPs in the wavelength range of 400-500 nm using a spectrometer equipped with cooled charged coupled devices (CCD) during irradiation by different intensities of 1 MHz ultrasound and IPL pulses. In order to confirm these results, the terephthalic acid chemical dosimeter was utilized as well. The SCL signal recorded in the gel phantoms containing GNPs at different intensities of ultrasound in the presence of intense pulsed light was higher than the gel phantoms without GNPs. These results have been confirmed by the obtained data from the chemical dosimetry method. Acoustic cavitation in the presence of GNPs and intense pulsed light has been suggested as a new approach designed for decreasing threshold intensity of acoustic cavitation and improving targeted therapeutic effects. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Polarized light modulates light-dependent magnetic compass orientation in birds

    Science.gov (United States)

    Muheim, Rachel; Sjöberg, Sissel; Pinzon-Rodriguez, Atticus

    2016-01-01

    Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarized light, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarized light cues in a four-arm “plus” maze. The birds did not use overhead polarized light near the zenith for sky compass orientation. Instead, overhead polarized light modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarized light axis aligned parallel to the magnetic field. When the polarized light axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarized light and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth’s magnetic field. PMID:26811473

  2. Optical particle trapping and dynamic manipulation using spatial light modulation

    DEFF Research Database (Denmark)

    Eriksen, René Lynge

    suitable for optical trapping. A phaseonly spatial light modulator (SLM) is used for the phase encoding of the laser beam. The SLM is controlled directly from a standard computer where phase information is represented as gray-scale image information. Experimentally, both linear and angular movements......This thesis deals with the spatial phase-control of light and its application for optical trapping and manipulation of micron-scale objects. Utilizing the radiation pressure, light exerts on dielectric micron-scale particles, functionality of optical tweezers can be obtained. Multiple intensity...... compression factors of two, which is not achievable with binary phase encoding, have been successfully demonstrated. In addition, the GPC method has been miniaturized and implemented in a planar optical platform and shown to work acceptably, with relatively high visibility. Furthermore, the GPC method has...

  3. Effects of acoustic radiation force and shear waves for absorption and stiffness sensing in ultrasound modulated optical tomography.

    Science.gov (United States)

    Li, Rui; Elson, Daniel S; Dunsby, Chris; Eckersley, Robert; Tang, Meng-Xing

    2011-04-11

    Ultrasound-modulated optical tomography (UOT) combines optical contrast with ultrasound spatial resolution and has great potential for soft tissue functional imaging. One current problem with this technique is the weak optical modulation signal, primarily due to strong optical scattering in diffuse media and minimal acoustically induced modulation. The acoustic radiation force (ARF) can create large particle displacements in tissue and has been shown to be able to improve optical modulation signals. However, shear wave propagation induced by the ARF can be a significant source of nonlocal optical modulation which may reduce UOT spatial resolution and contrast. In this paper, the time evolution of shear waves was examined on tissue mimicking-phantoms exposed to 5 MHz ultrasound and 532 nm optical radiation and measured with a CCD camera. It has been demonstrated that by generating an ARF with an acoustic burst and adjusting both the timing and the exposure time of the CCD measurement, optical contrast and spatial resolution can be improved by ~110% and ~40% respectively when using the ARF rather than 5 MHz ultrasound alone. Furthermore, it has been demonstrated that this technique simultaneously detects both optical and mechanical contrast in the medium and the optical and mechanical contrast can be distinguished by adjusting the CCD exposure time. © 2011 Optical Society of America

  4. Optical trapping and tweezing using a spatial light modulator

    CSIR Research Space (South Africa)

    Ismail, Y

    2009-07-01

    Full Text Available using a spatial light modulator Y.Ismail1,2, M. G. Mclaren1,3, A. Forbes1,2,4 1 CSIR National Laser Centre 2 School of Physics, University of KwaZulu-Natal 3 School of Physics, University of the Witwatersrand 4 School of Physics, University... of Stellenbosch Presented at the 2009 South African Institute of Physics Annual Conference University of KwaZulu-Natal Durban, South Africa 6-10 July 2009 Optical tweezing is based on the manipulation of micron sized particles in 3 dimensions 100X...

  5. Diffuse optical imaging using spatially and temporally modulated light

    Science.gov (United States)

    O'Sullivan, Thomas D.; Cerussi, Albert E.; Cuccia, David J.; Tromberg, Bruce J.

    2012-07-01

    The authors describe the development of diffuse optical imaging (DOI) technologies, specifically the use of spatial and temporal modulation to control near infrared light propagation in thick tissues. We present theory and methods of DOI focusing on model-based techniques for quantitative, in vivo measurements of endogenous tissue absorption and scattering properties. We specifically emphasize the common conceptual framework of the scalar photon density wave for both temporal and spatial frequency-domain approaches. After presenting the history, theoretical foundation, and instrumentation related to these methods, we provide a brief review of clinical and preclinical applications from our research as well as our outlook on the future of DOI technology.

  6. Aberration compensation using a spatial light modulator LCD

    International Nuclear Information System (INIS)

    Amezquita, R; Rincon, O; Torres, Y M

    2011-01-01

    The dynamic correction of aberrations introduced in optical systems have been a widely discussed topic in the past 10 years. Adaptive optics is the most important developed field where the Shack-Hartmann sensors and deformable mirrors are used for the measurement and correction of wavefronts. In this paper, an interferometric set-up which uses a Spatial Light Modulator (SLM) as an active element is proposed. Using this SLM a procedure for the compensation of all phase aberrations present in the experimental setup is shown.

  7. Focused ultrasound-modulated glomerular ultrafiltration assessed by functional changes in renal arteries.

    Directory of Open Access Journals (Sweden)

    Feng-Yi Yang

    Full Text Available This study demonstrates the feasibility of using focused ultrasound (FUS to modulate glomerular ultrafiltration by renal artery sonication and determine if protein-creatinine ratios are estimated through vascular parameters. All animal experiments were approved by our Animal Care and Use Committee. The renal arteries of Sprague-Dawley rats were surgically exposed and sonicated at various acoustic power levels using a FUS transducer with a resonant frequency of 1 MHz. The mean peak systolic velocity (PSV of the blood flow was measured by Doppler ultrasound imaging. Urinary protein-creatinine ratios were calculated during the experiments. Histological examination of renal arteries and whole kidneys was performed. The PSV, pulsatility index, and resistance index of blood flow significantly increased in the arteries after FUS sonication without microbubbles (p<0.05. The change in normalized protein-creatinine ratios significantly increased with increasing acoustic power, but such was not observed when microbubbles were administered. Furthermore, no histological changes were observed in the hematoxylin- and eosin-stained sections. Glomerular ultrafiltration is regulated temporarily by renal artery sonication without microbubbles. Monitoring vascular parameters are useful in estimating the normalized change in protein-creatinine ratios.

  8. Recent advances in IR liquid crystal spatial light modulators

    Science.gov (United States)

    Peng, Fenglin; Twieg, Robert J.; Wu, Shin-Tson

    2015-09-01

    Liquid crystal (LC) is an amazing class of electro-optic media; its applications span from visible to infrared, millimeter wave, and terahertz regions. In the visible and short-wavelength infrared (SWIR) regions, most LCs are highly transparent. However, to extend the electro-optic application of LCs into MWIR and LWIR, several key technical challenges have to be overcome: (1) low absorption loss, (2) high birefringence, (3) low operation voltage, and (4) fast response time. In the MWIR and LWIR regions, several fundamental molecular vibration bands and overtones exist, which contribute to high absorption loss. The absorbed light turns to heat and then alters the birefringence locally, which in turns causes spatially non-uniform phase modulation. To suppress the optical loss, several approaches have been investigated: (1) Employing thin cell gap by choosing a high birefringence LC mixture; (2) Shifting the absorption bands outside the spectral region of interest by deuteration, fluorination, or chlorination; (3) Reducing the overtone absorption by using a short alkyl chain. In this paper, we report some recently developed chlorinated LC compounds and mixtures with low absorption loss in the SWIR and MWIR regions. To achieve fast response time, we demonstrated a polymer network liquid crystal with 2π phase change at MWIR and response time less than 5 ms. Approaches to extend such a liquid crystal spatial light modulator to long-wavelength infrared will be discussed.

  9. Virtual reality 3D headset based on DMD light modulators

    Science.gov (United States)

    Bernacki, Bruce E.; Evans, Allan; Tang, Edward

    2014-06-01

    We present the design of an immersion-type 3D headset suitable for virtual reality applications based upon digital micromirror devices (DMD). Current methods for presenting information for virtual reality are focused on either polarizationbased modulators such as liquid crystal on silicon (LCoS) devices, or miniature LCD or LED displays often using lenses to place the image at infinity. LCoS modulators are an area of active research and development, and reduce the amount of viewing light by 50% due to the use of polarization. Viewable LCD or LED screens may suffer low resolution, cause eye fatigue, and exhibit a "screen door" or pixelation effect due to the low pixel fill factor. Our approach leverages a mature technology based on silicon micro mirrors delivering 720p resolution displays in a small form-factor with high fill factor. Supporting chip sets allow rapid integration of these devices into wearable displays with high-definition resolution and low power consumption, and many of the design methods developed for DMD projector applications can be adapted to display use. Potential applications include night driving with natural depth perception, piloting of UAVs, fusion of multiple sensors for pilots, training, vision diagnostics and consumer gaming. Our design concept is described in which light from the DMD is imaged to infinity and the user's own eye lens forms a real image on the user's retina resulting in a virtual retinal display.

  10. Carrier Modulation Layer-Enhanced Organic Light-Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Jwo-Huei Jou

    2015-07-01

    Full Text Available Organic light-emitting diode (OLED-based display products have already emerged in the market and their efficiencies and lifetimes are sound at the comparatively low required luminance. To realize OLED for lighting application sooner, higher light quality and better power efficiency at elevated luminance are still demanded. This review reveals the advantages of incorporating a nano-scale carrier modulation layer (CML, also known as a spacer, carrier-regulating layer, or interlayer, among other terms, to tune the chromaticity and color temperature as well as to markedly improve the device efficiency and color rendering index (CRI for numerous OLED devices. The functions of the CML can be enhanced as multiple layers and blend structures are employed. At proper thickness, the employment of CML enables the device to balance the distribution of carriers in the two emissive zones and achieve high device efficiencies and long operational lifetime while maintaining very high CRI. Moreover, we have also reviewed the effect of using CML on the most significant characteristics of OLEDs, namely: efficiency, luminance, life-time, CRI, SRI, chromaticity, and the color temperature, and see how the thickness tuning and selection of proper CML are crucial to effectively control the OLED device performance.

  11. Scalable Light Module for Low-Cost, High-Efficiency Light- Emitting Diode Luminaires

    Energy Technology Data Exchange (ETDEWEB)

    Tarsa, Eric [Cree, Inc., Goleta, CA (United States)

    2015-08-31

    During this two-year program Cree developed a scalable, modular optical architecture for low-cost, high-efficacy light emitting diode (LED) luminaires. Stated simply, the goal of this architecture was to efficiently and cost-effectively convey light from LEDs (point sources) to broad luminaire surfaces (area sources). By simultaneously developing warm-white LED components and low-cost, scalable optical elements, a high system optical efficiency resulted. To meet program goals, Cree evaluated novel approaches to improve LED component efficacy at high color quality while not sacrificing LED optical efficiency relative to conventional packages. Meanwhile, efficiently coupling light from LEDs into modular optical elements, followed by optimally distributing and extracting this light, were challenges that were addressed via novel optical design coupled with frequent experimental evaluations. Minimizing luminaire bill of materials and assembly costs were two guiding principles for all design work, in the effort to achieve luminaires with significantly lower normalized cost ($/klm) than existing LED fixtures. Chief project accomplishments included the achievement of >150 lm/W warm-white LEDs having primary optics compatible with low-cost modular optical elements. In addition, a prototype Light Module optical efficiency of over 90% was measured, demonstrating the potential of this scalable architecture for ultra-high-efficacy LED luminaires. Since the project ended, Cree has continued to evaluate optical element fabrication and assembly methods in an effort to rapidly transfer this scalable, cost-effective technology to Cree production development groups. The Light Module concept is likely to make a strong contribution to the development of new cost-effective, high-efficacy luminaries, thereby accelerating widespread adoption of energy-saving SSL in the U.S.

  12. Light Microscopy Module: International Space Station Premier Automated Microscope

    Science.gov (United States)

    Sicker, Ronald J.; Foster, William M.; Motil, Brian J.; Meyer, William V.; Chiaramonte, Francis P.; Abbott-Hearn, Amber; Atherton, Arthur; Beltram, Alexander; Bodzioney, Christopher; Brinkman, John; hide

    2016-01-01

    The Light Microscopy Module (LMM) was launched to the International Space Station (ISS) in 2009 and began hardware operations in 2010. It continues to support Physical and Biological scientific research on ISS. During 2016, if all goes as planned, three experiments will be completed: [1] Advanced Colloids Experiments with Heated base-2 (ACE-H2) and [2] Advanced Colloids Experiments with Temperature control (ACE-T1). Preliminary results, along with an overview of present and future LMM capabilities will be presented; this includes details on the planned data imaging processing and storage system, along with the confocal upgrade to the core microscope. [1] a consortium of universities from the State of Kentucky working through the Experimental Program to Stimulate Competitive Research (EPSCoR): Stuart Williams, Gerold Willing, Hemali Rathnayake, et al. and [2] from Chungnam National University, Daejeon, S. Korea: Chang-Soo Lee, et al.

  13. Estimation and Compensation of aberrations in Spatial Light Modulators

    International Nuclear Information System (INIS)

    Arias, Augusto; Castaneda, Roman

    2011-01-01

    The spatial light modulator (SLM) Holoeye LC-R720 is based on LCoS (Liquid Crystal on Silicon) technology. Due to the induced curvatures on the silicon plate by the production process, there are static aberrations in the wave-fronts modified by the SLM. In order to calculate the aberrated wave-front we used phase-shifting interferometry, an optimization algorithm for far field propagation, and the geometric characterization of the focal spot along the caustic. Zernike polynomials were used for expanding and comparing the wave-fronts. The aberration compensation was carried out by displaying the conjugated transmittance on the SLM. The complexity of the experimental setup and the requirements of the digital processing of each estimation method were comparatively analyzed.

  14. CFTR Modulators: Shedding Light on Precision Medicine for Cystic Fibrosis

    Science.gov (United States)

    Lopes-Pacheco, Miquéias

    2016-01-01

    Cystic fibrosis (CF) is the most common life-threatening monogenic disease afflicting Caucasian people. It affects the respiratory, gastrointestinal, glandular and reproductive systems. The major cause of morbidity and mortality in CF is the respiratory disorder caused by a vicious cycle of obstruction of the airways, inflammation and infection that leads to epithelial damage, tissue remodeling and end-stage lung disease. Over the past decades, life expectancy of CF patients has increased due to early diagnosis and improved treatments; however, these patients still present limited quality of life. Many attempts have been made to rescue CF transmembrane conductance regulator (CFTR) expression, function and stability, thereby overcoming the molecular basis of CF. Gene and protein variances caused by CFTR mutants lead to different CF phenotypes, which then require different treatments to quell the patients’ debilitating symptoms. In order to seek better approaches to treat CF patients and maximize therapeutic effects, CFTR mutants have been stratified into six groups (although several of these mutations present pleiotropic defects). The research with CFTR modulators (read-through agents, correctors, potentiators, stabilizers and amplifiers) has achieved remarkable progress, and these drugs are translating into pharmaceuticals and personalized treatments for CF patients. This review summarizes the main molecular and clinical features of CF, emphasizes the latest clinical trials using CFTR modulators, sheds light on the molecular mechanisms underlying these new and emerging treatments, and discusses the major breakthroughs and challenges to treating all CF patients. PMID:27656143

  15. Linearized image reconstruction method for ultrasound modulated electrical impedance tomography based on power density distribution

    International Nuclear Information System (INIS)

    Song, Xizi; Xu, Yanbin; Dong, Feng

    2017-01-01

    Electrical resistance tomography (ERT) is a promising measurement technique with important industrial and clinical applications. However, with limited effective measurements, it suffers from poor spatial resolution due to the ill-posedness of the inverse problem. Recently, there has been an increasing research interest in hybrid imaging techniques, utilizing couplings of physical modalities, because these techniques obtain much more effective measurement information and promise high resolution. Ultrasound modulated electrical impedance tomography (UMEIT) is one of the newly developed hybrid imaging techniques, which combines electric and acoustic modalities. A linearized image reconstruction method based on power density is proposed for UMEIT. The interior data, power density distribution, is adopted to reconstruct the conductivity distribution with the proposed image reconstruction method. At the same time, relating the power density change to the change in conductivity, the Jacobian matrix is employed to make the nonlinear problem into a linear one. The analytic formulation of this Jacobian matrix is derived and its effectiveness is also verified. In addition, different excitation patterns are tested and analyzed, and opposite excitation provides the best performance with the proposed method. Also, multiple power density distributions are combined to implement image reconstruction. Finally, image reconstruction is implemented with the linear back-projection (LBP) algorithm. Compared with ERT, with the proposed image reconstruction method, UMEIT can produce reconstructed images with higher quality and better quantitative evaluation results. (paper)

  16. Transcranial cavitation-mediated ultrasound therapy at sub-MHz frequency via temporal interference modulation

    Science.gov (United States)

    Sun, Tao; Sutton, Jonathan T.; Power, Chanikarn; Zhang, Yongzhi; Miller, Eric L.; McDannold, Nathan J.

    2017-10-01

    Sub-megahertz transmission is not usually adopted in pre-clinical small animal experiments for focused ultrasound (FUS) brain therapy due to the large focal size. However, low frequency FUS is vital for preclinical evaluations due to the frequency-dependence of cavitation behavior. To maximize clinical relevance, a dual-aperture FUS system was designed for low-frequency (274.3 kHz) cavitation-mediated FUS therapy. Combining two spherically curved transducers provides significantly improved focusing in the axial direction while yielding an interference pattern with strong side lobes, leading to inhomogeneously distributed cavitation activities. By operating the two transducers at slightly offset frequencies to modulate this interference pattern over the period of sonication, the acoustic energy was redistributed and resulted in a spatially homogenous treatment profile. Simulation and pressure field measurements in water were performed to assess the beam profiles. In addition, the system performance was demonstrated in vivo in rats via drug delivery through microbubble-mediated blood-brain barrier disruption. This design resulted in a homogenous treatment profile that was fully contained within the rat brain at a clinically relevant acoustic frequency.

  17. Light Microsopy Module, International Space Station Premier Automated Microscope

    Science.gov (United States)

    Meyer, William V.; Sicker, Ronald J.; Chiaramonte, Francis P.; Brown, Daniel F.; O'Toole, Martin A.; Foster, William M.; Motil, Brian J.; Abbot-Hearn, Amber Ashley; Atherton, Arthur Johnson; Beltram, Alexander; hide

    2015-01-01

    The Light Microscopy Module (LMM) was launched to the International Space Station (ISS) in 2009 and began science operations in 2010. It continues to support Physical and Biological scientific research on ISS. During 2015, if all goes as planned, five experiments will be completed: [1] Advanced Colloids Experiments with a manual sample base -3 (ACE-M-3), [2] the Advanced Colloids Experiment with a Heated Base -1 (ACE-H-1), [3] (ACE-H-2), [4] the Advanced Plant Experiment -03 (APEX-03), and [5] the Microchannel Diffusion Experiment (MDE). Preliminary results, along with an overview of present and future LMM capabilities will be presented; this includes details on the planned data imaging processing and storage system, along with the confocal upgrade to the core microscope. [1] New York University: Paul Chaikin, Andrew Hollingsworth, and Stefano Sacanna, [2] University of Pennsylvania: Arjun Yodh and Matthew Gratale, [3] a consortium of universities from the State of Kentucky working through the Experimental Program to Stimulate Competitive Research (EPSCoR): Stuart Williams, Gerold Willing, Hemali Rathnayake, et al., [4] from the University of Florida and CASIS: Anna-Lisa Paul and Rob Ferl, and [5] from the Methodist Hospital Research Institute from CASIS: Alessandro Grattoni and Giancarlo Canavese.

  18. Graphene metamaterial spatial light modulator for infrared single pixel imaging.

    Science.gov (United States)

    Fan, Kebin; Suen, Jonathan Y; Padilla, Willie J

    2017-10-16

    High-resolution and hyperspectral imaging has long been a goal for multi-dimensional data fusion sensing applications - of interest for autonomous vehicles and environmental monitoring. In the long wave infrared regime this quest has been impeded by size, weight, power, and cost issues, especially as focal-plane array detector sizes increase. Here we propose and experimentally demonstrated a new approach based on a metamaterial graphene spatial light modulator (GSLM) for infrared single pixel imaging. A frequency-division multiplexing (FDM) imaging technique is designed and implemented, and relies entirely on the electronic reconfigurability of the GSLM. We compare our approach to the more common raster-scan method and directly show FDM image frame rates can be 64 times faster with no degradation of image quality. Our device and related imaging architecture are not restricted to the infrared regime, and may be scaled to other bands of the electromagnetic spectrum. The study presented here opens a new approach for fast and efficient single pixel imaging utilizing graphene metamaterials with novel acquisition strategies.

  19. Are Live Ultrasound Models Replaceable? Traditional vs. Simulated Education Module for FAST

    Directory of Open Access Journals (Sweden)

    Suzanne Bentley

    2015-10-01

    Full Text Available Introduction: The focused assessment with sonography for trauma (FAST is a commonly used and life-saving tool in the initial assessment of trauma patients. The recommended emergency medicine (EM curriculum includes ultrasound and studies show the additional utility of ultrasound training for medical students. EM clerkships vary and often do not contain formal ultrasound instruction. Time constraints for facilitating lectures and hands-on learning of ultrasound are challenging. Limitations on didactics call for development and inclusion of novel educational strategies, such as simulation. The objective of this study was to compare the test, survey, and performance of ultrasound between medical students trained on an ultrasound simulator versus those trained via traditional, hands-on patient format. Methods: This was a prospective, blinded, controlled educational study focused on EM clerkship medical students. After all received a standardized lecture with pictorial demonstration of image acquisition, students were randomized into two groups: control group receiving traditional training method via practice on a human model and intervention group training via practice on an ultrasound simulator. Participants were tested and surveyed on indications and interpretation of FAST and training and confidence with image interpretation and acquisition before and after this educational activity. Evaluation of FAST skills was performed on a human model to emulate patient care and practical skills were scored via objective structured clinical examination (OSCE with critical action checklist. Results: There was no significant difference between control group (N=54 and intervention group (N=39 on pretest scores, prior ultrasound training/education, or ultrasound comfort level in general or on FAST. All students (N=93 showed significant improvement from pre- to post-test scores and significant improvement in comfort level using ultrasound in general and on FAST

  20. Electro-optic study of PZT ferroelectric ceramics using modulation of reflected light

    Science.gov (United States)

    Kniazkov, A. V.

    2016-04-01

    Electro-optic coefficients of variations in the refractive index of PZT and PLZT ceramic materials induced by ac electric field are estimated using modulation of reflected light. The electro-optic coefficients of PLZT ceramics measured with the aid of conventional birefringence using the phase shift of transmitted radiation and the proposed method of birefringence using the modulation of reflected light are compared.

  1. Multi-modality photoacoustic tomography, ultrasound, and light sheet microscopy for volumetric tumor margin detection

    Science.gov (United States)

    Sangha, Gurneet S.; Hu, Bihe; Bolus, Daniel; Wang, Mei; Skidmore, Shelby J.; Sholl, Andrew B.; Brown, J. Quincy; Goergen, Craig J.

    2018-02-01

    Current methods for breast tumor margin detection are invasive, time consuming, and typically result in a reoperative rate of over 25%. This marks a clear clinical need to develop improved tools to intraoperatively differentiate negative versus positive tumor margins. Here, we utilize photoacoustic tomography (PAT), ultrasound (US), and inverted Selective Plane Illumination Microscopy (iSPIM) to assess breast tumor margins in eight human breast biopsies. Our PAT/US system consists of a tunable Nd:YAG laser (NT 300, EKSPLA) coupled with a 40MHz central frequency US probe (Vevo2100, FUJIFILM Visual Sonics). This system allows for the delivery of 10Hz, 5ns pulses with fluence of 40mJ/cm2 to the tissue with PAT and US axial resolutions of 125μm and 40μm, respectively. For this study, we used a linear stepper motor to acquire volumetric PAT/US images of the breast biopsies using 1100nm light to identify bloodrich "tumor" regions and 1210nm light to identify lipid-rich "healthy" regions. iSPIM (Applied Scientific Instrumentation) is an advanced microscopy technique with lateral resolution of 1.5μm and axial resolution of 7μm. We used 488nm laser excitation and acridine orange as a general comprehensive histology stain. Our results show that PAT/US can be used to identify lipid-rich regions, dense areas of arterioles and arteries, and other internal structures such as ducts. iSPIM images correlate well with histopathology slides and can verify nuclear features, cell type and density, stromal features, and microcalcifications. Together, this multimodality approach has the potential to improve tumor margin detection with a high degree of sensitivity and specificity.

  2. Influence of power density on the setting behaviour of light-cured glass-ionomer cements monitored by ultrasound measurements.

    Science.gov (United States)

    Tonegawa, Motoka; Yasuda, Genta; Chikako, Takubo; Tamura, Yukie; Yoshida, Takeshi; Kurokawa, Hiroyasu; Miyazaki, Masashi

    2009-07-01

    To monitor the influence of the power density of the curing unit on the setting behaviour of light-cured glass-ionomer cements (LCGICs) using ultrasound measurements. The ultrasound equipment comprised a pulser-receiver, transducers and an oscilloscope. The LCGICs used were Fuji II LC, Fuji II LC EM and Fuji Filling LC. The cements were mixed according to the manufacturer's instructions and then inserted into a transparent mould. The specimens were placed on the sample stage and cured with power densities of 0 (no irradiation), 200 or 600 mW/cm(2). The transit time through the cement disk was divided by the specimen thickness and then the longitudinal ultrasound velocity (V) within the material was obtained. Analysis of variance and Tukey's Honestly Significantly Different test were used to compare the V values between the set cements. When the LCGICs were light-irradiated, each curve displayed an initial plateau at approximately 1500 m/s and then rapidly increased to a second plateau at approximately 2600 m/s. The rate of increase of V was retarded when the cements were light-irradiated with a power density of 200 mW/cm(2) than with a power density of 600 mW/cm(2). Although sonic echoes were detected from the beginning of the measurements, the rates of increase of the sonic velocity were relatively slow when the cement was not light-irradiated. The ultrasound device monitored the setting processes of LCGICs accurately based on the longitudinal V. The polymerization behaviour of LCGICs was shown to be affected by the power density of the curing unit.

  3. Self-phase modulation of laser light in laser produced plasma

    International Nuclear Information System (INIS)

    Yamanaka, C.; Yamanaka, T.; Mizui, J.; Yamaguchi, N.

    1975-02-01

    A spectrum broadening due to the self-phase modulation of a laser light was observed in the laser produced deuterium and hydrogen plasma. Qualitative treatments of the density modulation due to the self-focusing process and the modulational instability were discussed. The theoretical estimation of spectrum broadening fairly accorded with the experimental results. (auth.)

  4. Ultrasound pregnancy

    Science.gov (United States)

    Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; ...

  5. Use of modulated excitation signals in ultrasound. Part II: Design and performance for medical imaging applications

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Jensen, Jørgen Arendt

    2005-01-01

    ultrasound presents design methods of linear FM signals and mismatched filters, in order to meet the higher demands on resolution in ultrasound imaging. It is shown that for the small time-bandwidth (TB) products available in ultrasound, the rectangular spectrum approximation is not valid, which reduces....... The method is evaluated first for resolution performance and axial sidelobes through simulations with the program Field II. A coded excitation ultrasound imaging system based on a commercial scanner and a 4 MHz probe driven by coded sequences is presented and used for the clinical evaluation of the coded...... excitation/compression scheme. The clinical images show a significant improvement in penetration depth and contrast, while they preserve both axial and lateral resolution. At the maximum acquisition depth of 15 cm, there is an improvement of more than 10 dB in the signal-to-noise ratio of the images...

  6. Performance comparison of binary modulation schemes for visible light communication

    KAUST Repository

    Park, Kihong; Li, Changping; Alouini, Mohamed-Slim

    2015-01-01

    communication with dimming control. We also propose a novel slope-based modulation called differential chip slope modulation (DCSM) and develop a chip-based hard-decision receiver to demodulate the resulting signal, detect the chip sequence, and decode the input

  7. Inhibition of light tunneling for multichannel excitations in longitudinally modulated waveguide arrays

    International Nuclear Information System (INIS)

    Lobanov, Valery E.; Vysloukh, Victor A.; Kartashov, Yaroslav V.

    2010-01-01

    We consider the evolution of multichannel excitations in longitudinally modulated waveguide arrays where the refractive index either oscillates out-of-phase in all neighboring waveguides or when it is modulated in phase in several central waveguides surrounded by out-of-phase oscillating neighbors. Both types of modulations allow resonant inhibition of light tunneling, but only the modulation of the latter type conserves the internal structure of multichannel excitations. We show that parameter regions where light tunneling inhibition is possible depend on the symmetry and structure of multichannel excitations. Antisymmetric multichannel excitations are more robust than their symmetric counterparts and experience nonlinearity-induced delocalization at higher amplitudes.

  8. Method and Apparatus for Characterizing Pressure Sensors using Modulated Light Beam Pressure

    Science.gov (United States)

    Youngquist, Robert C. (Inventor)

    2003-01-01

    Embodiments of apparatuses and methods are provided that use light sources instead of sound sources for characterizing and calibrating sensors for measuring small pressures to mitigate many of the problems with using sound sources. In one embodiment an apparatus has a light source for directing a beam of light on a sensing surface of a pressure sensor for exerting a force on the sensing surface. The pressure sensor generates an electrical signal indicative of the force exerted on the sensing surface. A modulator modulates the beam of light. A signal processor is electrically coupled to the pressure sensor for receiving the electrical signal.

  9. Observation Platform for Dynamic Biomedical and Biotechnology Experiments using the ISS Light Microscopy Module, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed "Observation platform for dynamic biomedical and biotechnology experiments using the ISS Light Microscopy Module" consists of a platen sized to fit the...

  10. Performance Stabilization of CdTe PV Modules using Bias and Light

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, T. J.; Deceglie, M. G.; Marion, B.; Kurtz, S. R.

    2014-07-01

    Reversible performance changes due to light exposure frustrate repeatable performance measurements on CdTe PV modules. It is common to use extended light-exposure to ensure that measurements are representative of outdoor performance. We quantify the extent to which such a light-exposed state depends on module temperature and consider bias in the dark to aid in stabilization. We evaluate the use of dark forward bias to bring about a performance state equivalent to that obtained with light exposure, and to maintain a light-exposed state prior to STC performance measurement. Our results indicate that the most promising method for measuring a light-exposed state is to use light exposure at controlled temperature followed by prompt STC measurement with a repeatable time interval between exposure and the STC measurement.

  11. Noninvasive focused ultrasound stimulation can modulate phase-amplitude coupling between neuronal oscillations in the rat hippocampus

    Directory of Open Access Journals (Sweden)

    Yi Yuan

    2016-07-01

    Full Text Available Noninvasive focused ultrasound stimulation (FUS can be used to modulate neural activity with high spatial resolution. Phase-amplitude coupling (PAC between neuronal oscillations is tightly associated with cognitive processes, including learning, attention and memory. In this study, we investigated the effect of FUS on PAC between neuronal oscillations and established the relationship between the PAC index and ultrasonic intensity. The rat hippocampus was stimulated using focused ultrasound at different spatial-average pulse-average ultrasonic intensities (3.9 W/cm2, 9.6 W/cm2, and 19.2 W/cm2. The local field potentials (LFPs in the rat hippocampus were recorded before and after FUS. Then, we analyzed PAC between neuronal oscillations using a PAC calculation algorithm. Our results showed that FUS significantly modulated PAC between the theta (4-8 Hz and gamma (30-80 Hz bands and between the alpha (9-13 Hz and ripple (81-200 Hz bands in the rat hippocampus, and PAC increased with incremental increases in ultrasonic intensity.

  12. The generation of flat-top beams by complex amplitude modulation with a phase-only spatial light modulator

    CSIR Research Space (South Africa)

    Hendriks, A

    2012-08-01

    Full Text Available amplitude modulation of the light, i.e., in amplitude and phase. We outline the theoretical concept, and then illustrate its use with the example of the laser beam shaping of Gaussian beams into flat-top beams. We quantify the performance of this approach...

  13. Polydyne displacement interferometer using frequency-modulated light

    Science.gov (United States)

    Arablu, Masoud; Smith, Stuart T.

    2018-05-01

    A radio-frequency Frequency-Modulated (FM) signal is used to diffract a He-Ne laser beam through an Acousto-Optic Modulator (AOM). Due to the modulation of the FM signal, the measured spectra of the diffracted beams comprise a series of phase-synchronized harmonics that have exact integer frequency separation. The first diffraction side-beam emerging from the AOM is selected by a slit to be used in a polydyne displacement interferometer in a Michelson interferometer topology. The displacement measurement is derived from the phase measurement of selected modulation harmonic pairs. Individual harmonic frequency amplitudes are measured using discrete Fourier transform applied to the signal from a single photodetector. Phase signals are derived from the changes in the amplitudes of different harmonic pairs (typically odd-even pairs) with the phase being extracted using a standard quadrature method. In this study, two different modulation frequencies of 5 and 10 kHz are used at different modulation depths. The measured displacements by different harmonic pairs are compared with a commercial heterodyne interferometer being used as a reference for these studies. Measurements obtained from five different harmonic pairs when the moving mirror of the interferometer is scanned over ranges up to 10 μm all show differences of less than 50 nm from the reference interferometer measurements. A drift test was also used to evaluate the differences between the polydyne interferometer and reference measurements that had different optical path lengths of approximately 25 mm and 50 mm, respectively. The drift test results indicate that about half of the differences can be attributed to temperature, pressure, and humidity variations. Other influences include Abbe and thermal expansion effects. Rough magnitude estimates using simple models for these two effects can account for remaining observed deviations.

  14. Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors.

    Science.gov (United States)

    Bonnineau, Chloé; Sague, Irene Gallardo; Urrea, Gemma; Guasch, Helena

    2012-05-01

    In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms' ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms' response to glyphosate, it had little influence on biofilms' response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC(50) = 11.7 mg L(-1)) than of high-light adapted communities (EC(50) = 35.6 mg L(-1)). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly.

  15. Concepts for external light trapping and its utilization in colored and image displaying photovoltaic modules

    NARCIS (Netherlands)

    van Dijk, L.; van de Groep, J.; Veldhuizen, L.W.; Di Vece, M.; Schropp, R.E.I.

    2017-01-01

    The reflection of incident sunlight prevents photovoltaic modules from reaching their full energy conversion potential. Recently, we demonstrated significant absorption enhancement in various solar cells by external light trapping, using 3D-printed and milled light traps. In order to facilitate

  16. Light modulators and deflectors based on polariton effects

    DEFF Research Database (Denmark)

    Skettrup, Torben

    1981-01-01

    , the polariton, and hence the photon part, can be deflected or modulated. The connection with geometrical optics is established, and it is shown that the deflection is due to a gradient in the refraction index created by the applied external field. Several examples with electric, magnetic, and stress fields...

  17. Implementation and utility of a daily ultrasound-based localization system with intensity-modulated radiotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Morr, Jody; DiPetrillo, Thomas; Tsai, J.-S.; Engler, Mark; Wazer, David E. MD.

    2002-01-01

    Purpose: To evaluate the clinical feasibility of daily computer-assisted transabdominal ultrasonography for target position verification in the setting of intensity-modulated radiotherapy (IMRT) for prostate cancer. Methods and Materials: Twenty-three patients with clinically localized prostate cancer were treated using a sequential tomotherapy IMRT technique (Peacock) and daily computer-assisted transabdominal ultrasonography (BAT) for target localization. Patients were instructed to maintain a full bladder and were placed in the supine position using triangulation tattoos and a leg immobilizer to minimize pelvic rotation. The BAT ultrasound system is docked to the treatment collimator and electronically imports the CT simulation target contours and isocenter. The system is able to use the machine isocenter as a reference point to overlay the corresponding CT contours onto the ultrasound images captured in the transverse and sagittal planes. A touch screen menu is used to maneuver the CT contours in three dimensions such that they match the ultrasound images. The system then displays the three-dimensional couch shifts required to produce field alignment. Data were prospectively collected to measure the frequency by which useful ultrasound images were obtained, the amount of time required for localization/setup, and the direction/magnitude of the positional adjustments. Results: Of the 23 patients, the BAT ultrasound system produced images of sufficient quality to perform the overlay of the CT contours in 19 patients such that positional verification could be reliably performed. Poor image quality was associated with patient inability to maintain a full bladder, large body habitus, or other anatomic constraints. Of the 19 assessable patients, a total of 185 treatment alignments were performed (mean 8.8/patient). For all cases, the average time required for the daily ultrasound imaging and positional adjustments was 11.9 min. After the initial 5 cases, the user

  18. Light and gravity signals synergize in modulating plant development

    Science.gov (United States)

    Vandenbrink, Joshua P.; Kiss, John Z.; Herranz, Raul; Medina, F. Javier

    2014-01-01

    Tropisms are growth-mediated plant movements that help plants to respond to changes in environmental stimuli. The availability of water and light, as well as the presence of a constant gravity vector, are all environmental stimuli that plants sense and respond to via directed growth movements (tropisms). The plant response to gravity (gravitropism) and the response to unidirectional light (phototropism) have long been shown to be interconnected growth phenomena. Here, we discuss the similarities in these two processes, as well as the known molecular mechanisms behind the tropistic responses. We also highlight research done in a microgravity environment in order to decouple two tropisms through experiments carried out in the absence of a significant unilateral gravity vector. In addition, alteration of gravity, especially the microgravity environment, and light irradiation produce important effects on meristematic cells, the undifferentiated, highly proliferating, totipotent cells which sustain plant development. Microgravity produces the disruption of meristematic competence, i.e., the decoupling of cell proliferation and cell growth, affecting the regulation of the cell cycle and ribosome biogenesis. Light irradiation, especially red light, mediated by phytochromes, has an activating effect on these processes. Phytohormones, particularly auxin, also are key mediators in these alterations. Upcoming experiments on the International Space Station will clarify some of the mechanisms and molecular players of the plant responses to these environmental signals involved in tropisms and the cell cycle. PMID:25389428

  19. Light and gravity signals synergize in modulating plant development

    Directory of Open Access Journals (Sweden)

    Joshua P. Vandenbrink

    2014-10-01

    Full Text Available Tropisms are growth-mediated plant movements that help plants to respond to changes in environmental stimuli. The availability of water and light, as well as the presence of a constant gravity vector, are all environmental stimuli that plants sense and respond to via directed growth movements (tropisms. The plant response to gravity (gravitropism and the response to unidirectional light (phototropism have long been shown to be interconnected growth phenomena. Here, we discuss the similarities in these two processes, as well as the known molecular mechanisms behind the tropistic responses. We also highlight experiments done in a microgravity environment in order to decouple two tropisms through experiments carried out in the absence of a significant unilateral gravity vector. In addition, alteration of gravity, especially the microgravity environment, and light irradiation produce important effects on meristematic cells, the undifferentiated, highly proliferating, totipotent cells which sustain plant development. Microgravity produces the disruption of meristematic competence, i.e. the decoupling of cell proliferation and cell growth, affecting the regulation of cell cycle and ribosome biogenesis. Light irradiation, especially red light, mediated by phytochromes, has an activating effect on these processes. Phytohormones, particularly auxin, are key mediators in these alterations. Upcoming experiments on the International Space Station will clarify some of the unknown mechanisms and molecular players of the plant responses to these environmental signals involved in tropisms and the cell cycle.

  20. Long-term storage life of light source modules by temperature cycling accelerated life test

    International Nuclear Information System (INIS)

    Sun Ningning; Tan Manqing; Li Ping; Jiao Jian; Guo Xiaofeng; Guo Wentao

    2014-01-01

    Light source modules are the most crucial and fragile devices that affect the life and reliability of the interferometric fiber optic gyroscope (IFOG). While the light emitting chips were stable in most cases, the module packaging proved to be less satisfactory. In long-term storage or the working environment, the ambient temperature changes constantly and thus the packaging and coupling performance of light source modules are more likely to degrade slowly due to different materials with different coefficients of thermal expansion in the bonding interface. A constant temperature accelerated life test cannot evaluate the impact of temperature variation on the performance of a module package, so the temperature cycling accelerated life test was studied. The main failure mechanism affecting light source modules is package failure due to solder fatigue failure including a fiber coupling shift, loss of cooling efficiency and thermal resistor degradation, so the Norris-Landzberg model was used to model solder fatigue life and determine the activation energy related to solder fatigue failure mechanism. By analyzing the test data, activation energy was determined and then the mean life of light source modules in different storage environments with a continuously changing temperature was simulated, which has provided direct reference data for the storage life prediction of IFOG. (semiconductor devices)

  1. White LEDs and modules in chip-on-board technology for general lighting

    Science.gov (United States)

    Hartmann, Paul; Wenzl, Franz P.; Sommer, Christian; Pachler, Peter; Hoschopf, Hans; Schweighart, Marko; Hartmann, Martin; Kuna, Ladislav; Jakopic, Georg; Leising, Guenther; Tasch, Stefan

    2006-08-01

    At present, light-emitting diode (LED) modules in various shapes are developed and designed for the general lighting, advertisement, emergency lighting, design and architectural markets. To compete with and to surpass the performance of traditional lighting systems, enhancement of Lumen output and the white light quality as well as the thermal management and the luminary integration are key factors for success. Regarding these issues, white LEDs based on the chip-on-board (COB) technology show pronounced advantages. State-of-the-art LEDs exploiting this technology are now ready to enter the general lighting segments. We introduce and discuss the specific properties of the Tridonic COB technology dedicated for general lighting. This technology, in combination with a comprehensive set of tools to improve and to enhance the Lumen output and the white light quality, including optical simulation, is the scaffolding for the application of white LEDs in emerging areas, for which an outlook will be given.

  2. A light-powered bio-capacitor with nanochannel modulation.

    Science.gov (United States)

    Rao, Siyuan; Lu, Shanfu; Guo, Zhibin; Li, Yuan; Chen, Deliang; Xiang, Yan

    2014-09-03

    An artificial bio-capacitor system is established, consisting of the proton-pump protein proteorhodopsin and a modified alumina nanochannel, inspired by the capacitor-like behavior of plasma membranes realized through the cooperation of ion-pump and ion-channel proteins. Capacitor-like features of this simplified system are realized and identified, and the photocurrent duration time can be modulated by nanochannel modification to obtain favorable square-wave currents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Common Envelope Light Curves. I. Grid-code Module Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Galaviz, Pablo; Marco, Orsola De; Staff, Jan E.; Iaconi, Roberto [Department of Physics and Astronomy, Macquarie University, Sydney, NSW (Australia); Passy, Jean-Claude, E-mail: Pablo.Galaviz@me.com [Argelander-Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn (Germany)

    2017-04-01

    The common envelope (CE) binary interaction occurs when a star transfers mass onto a companion that cannot fully accrete it. The interaction can lead to a merger of the two objects or to a close binary. The CE interaction is the gateway of all evolved compact binaries, all stellar mergers, and likely many of the stellar transients witnessed to date. CE simulations are needed to understand this interaction and to interpret stars and binaries thought to be the byproduct of this stage. At this time, simulations are unable to reproduce the few observational data available and several ideas have been put forward to address their shortcomings. The need for more definitive simulation validation is pressing and is already being fulfilled by observations from time-domain surveys. In this article, we present an initial method and its implementation for post-processing grid-based CE simulations to produce the light curve so as to compare simulations with upcoming observations. Here we implemented a zeroth order method to calculate the light emitted from CE hydrodynamic simulations carried out with the 3D hydrodynamic code Enzo used in unigrid mode. The code implements an approach for the computation of luminosity in both optically thick and optically thin regimes and is tested using the first 135 days of the CE simulation of Passy et al., where a 0.8  M {sub ⊙} red giant branch star interacts with a 0.6  M {sub ⊙} companion. This code is used to highlight two large obstacles that need to be overcome before realistic light curves can be calculated. We explain the nature of these problems and the attempted solutions and approximations in full detail to enable the next step to be identified and implemented. We also discuss our simulation in relation to recent data of transients identified as CE interactions.

  4. Virtual reality 3D headset based on DMD light modulators

    Energy Technology Data Exchange (ETDEWEB)

    Bernacki, Bruce E.; Evans, Allan; Tang, Edward

    2014-06-13

    We present the design of an immersion-type 3D headset suitable for virtual reality applications based upon digital micro-mirror devices (DMD). Our approach leverages silicon micro mirrors offering 720p resolution displays in a small form-factor. Supporting chip sets allow rapid integration of these devices into wearable displays with high resolution and low power consumption. Applications include night driving, piloting of UAVs, fusion of multiple sensors for pilots, training, vision diagnostics and consumer gaming. Our design is described in which light from the DMD is imaged to infinity and the user’s own eye lens forms a real image on the user’s retina.

  5. Light modulated toxicity of isoproturon toward natural stream periphyton photosynthesis: a comparison between constant and dynamic light conditions.

    Science.gov (United States)

    Laviale, Martin; Prygiel, Jean; Créach, Anne

    2010-05-10

    This study tested if a variation in light intensity, in comparison to constant light required in well-designed toxicity test, could have measurable consequences on the sensitivity of phototrophic biofilms (periphyton) to isoproturon. Two independent experiments were carried out to investigate the combined effects of light and isoproturon on the photochemical behavior of intact natural biofilms by measurements of chlorophyll fluorescence and pigment composition. Experiment 1 consisted of exposing biofilms to series of isoproturon concentrations (0-2 mg L(-1)) for 7 h under constant light at different irradiance levels (25-300 micromol m(-2) s(-1)). In experiment 2, biofilms were exposed using more environmentally realistic conditions to three selected concentrations of isoproturon (2, 6 and 20 microg L(-1)) during a 7-h-simulated daily light cycle. Our results demonstrated that light, considered here as a direct physical stressor, slightly modulated the acute toxicity of isoproturon on these diatom dominated communities. This was attributed to the fact that these two factors act specifically on the photosynthetic activity. Furthermore, it was shown that a dynamic light regime increased periphyton sensitivity to isoproturon by challenging its photoprotective mechanisms such as the xanthophyll cycle, therefore implying that traditional ecotoxicological bioassays lead to underestimate the effect of isoproturon. 2010 Elsevier B.V. All rights reserved.

  6. Generating shaped femtosecond pulses in the far infrared using a spatial light modulator and difference frequency generation

    CSIR Research Space (South Africa)

    Botha, N

    2010-08-31

    Full Text Available Femtosecond pulse shaping can be done by different kinds of pulse shapers, such as liquid crystal spatial light modulators (LC SLM), acousto optic modulators (AOM) and deformable and movable mirrors. A few applications where pulse shaping...

  7. The velocity of light intensity increase modulates the photoprotective response in coastal diatoms.

    Directory of Open Access Journals (Sweden)

    Vasco Giovagnetti

    Full Text Available In aquatic ecosystems, the superimposition of mixing events to the light diel cycle exposes phytoplankton to changes in the velocity of light intensity increase, from diurnal variations to faster mixing-related ones. This is particularly true in coastal waters, where diatoms are dominant. This study aims to investigate if coastal diatoms differently activate the photoprotective responses, xanthophyll cycle (XC and non-photochemical fluorescence quenching (NPQ, to cope with predictable light diel cycle and unpredictable mixing-related light variations. We compared the effect of two fast light intensity increases (simulating mixing events with that of a slower increase (corresponding to the light diel cycle on the modulation of XC and NPQ in the planktonic coastal diatom Pseudo-nitzschia multistriata. During each light treatment, the photon flux density (PFD progressively increased from darkness to five peaks, ranging from 100 to 650 µmol photons m-2 s-1. Our results show that the diel cycle-related PFD increase strongly activates XC through the enhancement of the carotenoid biosynthesis and induces a moderate and gradual NPQ formation over the light gradient. In contrast, during mixing-related PFD increases, XC is less activated, while higher NPQ rapidly develops at moderate PFD. We observe that together with the light intensity and its increase velocity, the saturation light for photosynthesis (Ek is a key parameter in modulating photoprotection. We propose that the capacity to adequately regulate and actuate alternative photoprotective 'safety valves' in response to changing velocity of light intensity increase further enhances the photophysiological flexibility of diatoms. This might be an evolutionary outcome of diatom adaptation to turbulent marine ecosystems characterized by unpredictable mixing-related light changes over the light diel cycle.

  8. Enhancement of mosquito trapping efficiency by using pulse width modulated light emitting diodes

    OpenAIRE

    Liu, Yu-Nan; Liu, Yu-Jen; Chen, Yi-Chian; Ma, Hsin-Yi; Lee, Hsiao-Yi

    2017-01-01

    In this study, a light-driving bug zapper is presented for well controlling the diseases brought by insects, such as mosquitoes. In order to have the device efficient to trap the insect pests in off-grid areas, pulse width modulated light emitting diodes (PWM-LED) combined with a solar power module are proposed and implemented. With specific PWM electric signals to drive the LED, it is found that no matter what the ability of catching insects or the consumed power efficiency can be enhanced t...

  9. Super-resolution with an optically-addressable liquid crystal spatial light modulator

    International Nuclear Information System (INIS)

    McOrist, J.; Sharma, M.D.; Sheppard, C.J.R.

    2002-01-01

    Full text: An optically-addressable liquid crystal spatial light modulator has been used to generate super-resolving masks. This approach avoids problems of low efficiency and coupling between amplitude and phase modulation, that occur when using conventional liquid crystal modulators. When addressed by a programmed light intensity distribution, it allows filters to be changed rapidly to modify the response of a system or permit the investigation of different filter designs. The device used is not pixellated, with a spatial resolution of 30 line pairs/mm over an area 18mm X 18mm, and can achieve continuously-variable phase modulation up to 1.5 wavelengths. The system consists of a write-beam that is collimated from a white-light source. An input mask was used in our experiments determines the modulation pattern of the read-beam. The read-beam from a HeNe laser reflects from the modulator and is focused by a microscope objective. The value of the phase change induced by the transparent regions of the mask can be altered continuously by adjusting the brightness of the write-beam. We have used this system to attain super-resolution by simple Toraldo filters, consisting of arrays of rings. Copyright (2002) Australian Society for Electron Microscopy Inc

  10. Color design model of high color rendering index white-light LED module.

    Science.gov (United States)

    Ying, Shang-Ping; Fu, Han-Kuei; Hsieh, Hsin-Hsin; Hsieh, Kun-Yang

    2017-05-10

    The traditional white-light light-emitting diode (LED) is packaged with a single chip and a single phosphor but has a poor color rendering index (CRI). The next-generation package comprises two chips and a single phosphor, has a high CRI, and retains high luminous efficacy. This study employs two chips and two phosphors to improve the diode's color tunability with various proportions of two phosphors and various densities of phosphor in the silicone used. A color design model is established for color fine-tuning of the white-light LED module. The maximum difference between the measured and color-design-model simulated CIE 1931 color coordinates is approximately 0.0063 around a correlated color temperature (CCT) of 2500 K. This study provides a rapid method to obtain the color fine-tuning of a white-light LED module with a high CRI and luminous efficacy.

  11. Road crossing behavior under traffic light conflict: Modulating effects of green light duration and signal congruency.

    Science.gov (United States)

    Lange, Florian; Haiduk, Michael; Boos, Moritz; Tinschert, Peter; Schwarze, Anke; Eggert, Frank

    2016-10-01

    A large number of pedestrians and cyclists regularly ignore the traffic lights to cross the road illegally. In a recent analysis, illegal road crossing behavior has been shown to be enhanced in the presence of incongruent stimulus configurations. Pedestrians and cyclists are more likely to cross against a red light when exposed to an irrelevant conflicting green light. Here, we present experimental and observational data on the factors moderating the risk associated with incongruent traffic lights. In an observational study, we demonstrated that the conflict-related increase in illegal crossing rates is reduced when pedestrian and cyclist green light periods are long. In a laboratory experiment, we manipulated the color of the irrelevant signals to expose participants to different degrees of incongruency. Results revealed that individuals' performance gradually varied as a function of incongruency, suggesting that the negative impact of a conflicting green light can be reduced by slightly adjusting its color. Our findings highlight that the observation of real-world behavior at intersections and the experimental analysis of psychological processes under controlled laboratory conditions can complement each other in identifying risk factors of risky road crossing behavior. Based on this combination, our study elaborates on promising measures to improve safety at signalized intersections. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Exploiting total internal reflection geometry for efficient optical modulation of terahertz light

    Directory of Open Access Journals (Sweden)

    Xudong Liu

    2016-10-01

    Full Text Available Efficient methods to modulate terahertz (THz light are essential for realizing rapid THz imaging and communication applications. Here we report a novel THz modulator which utilizes the evanescent wave in a total internal reflection setup coupled with a conductive interface to enhance the attenuation efficiency of THz light. This approach makes it possible to achieve close to 100% modulation with a small interface conductivity of 12 mS. The frequency dependence of this technique is linked to the optical properties of the materials: a material with close to frequency independent conductivity that is also controllable will result in an achromatic modulation response, and the device performance can be optimized further by tuning the internal reflection angle. In this work, we focus on applying the technique in the terahertz frequency range. Using an LED array with a pump intensity of 475 mW/cm2 to produce carriers in a silicon wafer, we have achieved a modulation depth of up to 99.9% in a broad frequency range of 0.1 THz–0.8 THz. The required pumping power for the generation of the required free carriers is low because the sheet conductivity needed is far less than required for traditional transmission techniques. Consequently, the device can be modulated by an LED making it a very practical, low cost, and scalable solution for THz modulation.

  13. Study of LED modulation effect on the photometric quantities and beam homogeneity of automotive lighting

    Science.gov (United States)

    Koudelka, Petr; Hanulak, Patrik; Jaros, Jakub; Papes, Martin; Latal, Jan; Siska, Petr; Vasinek, Vladimir

    2015-07-01

    This paper discusses the implementation of a light emitting diode based visible light communication system for optical vehicle-to-vehicle (V2V) communications in road safety applications. The widespread use of LEDs as light sources has reached into automotive fields. For example, LEDs are used for taillights, daytime running lights, brake lights, headlights, and traffic signals. Future in the optical vehicle-to-vehicle (V2V) communications will be based on an optical wireless communication technology that using LED transmitter and a camera receiver (OCI; optical communication image sensor). Utilization of optical V2V communication systems in automotive industry naturally brings a lot of problems. Among them belongs necessity of circuit implementation into the current concepts of electronic LED lights control that allows LED modulation. These circuits are quite complicated especially in case of luxury cars. Other problem is correct design of modulation circuits so that final vehicle lightning using optical vehicle-to-vehicle (V2V) communication meets standard requirements on Photometric Quantities and Beam Homogeneity. Authors of this article performed research on optical vehicle-to-vehicle (V2V) communication possibilities of headlight (Jaguar) and taillight (Skoda) in terms of modulation circuits (M-PSK, M-QAM) implementation into the lamp concepts and final fulfilment of mandatory standards on Photometric Quantities and Beam Homogeneity.

  14. Three-dimension reconstruction based on spatial light modulator

    International Nuclear Information System (INIS)

    Deng Xuejiao; Zhang Nanyang; Zeng Yanan; Yin Shiliang; Wang Weiyu

    2011-01-01

    Three-dimension reconstruction, known as an important research direction of computer graphics, is widely used in the related field such as industrial design and manufacture, construction, aerospace, biology and so on. Via such technology we can obtain three-dimension digital point cloud from a two-dimension image, and then simulate the three-dimensional structure of the physical object for further study. At present, the obtaining of three-dimension digital point cloud data is mainly based on the adaptive optics system with Shack-Hartmann sensor and phase-shifting digital holography. Referring to surface fitting, there are also many available methods such as iterated discrete fourier transform, convolution and image interpolation, linear phase retrieval. The main problems we came across in three-dimension reconstruction are the extraction of feature points and arithmetic of curve fitting. To solve such problems, we can, first of all, calculate the relevant surface normal vector information of each pixel in the light source coordinate system, then these vectors are to be converted to the coordinates of image through the coordinate conversion, so the expectant 3D point cloud get arise. Secondly, after the following procedures of de-noising, repairing, the feature points can later be selected and fitted to get the fitting function of the surface topography by means of Zernike polynomial, so as to reconstruct the determinand's three-dimensional topography. In this paper, a new kind of three-dimension reconstruction algorithm is proposed, with the assistance of which, the topography can be estimated from its grayscale at different sample points. Moreover, the previous stimulation and the experimental results prove that the new algorithm has a strong capability to fit, especially for large-scale objects .

  15. Three-dimension reconstruction based on spatial light modulator

    Energy Technology Data Exchange (ETDEWEB)

    Deng Xuejiao; Zhang Nanyang; Zeng Yanan; Yin Shiliang; Wang Weiyu, E-mail: daisydelring@yahoo.com.cn [Huazhong University of Science and Technology (China)

    2011-02-01

    Three-dimension reconstruction, known as an important research direction of computer graphics, is widely used in the related field such as industrial design and manufacture, construction, aerospace, biology and so on. Via such technology we can obtain three-dimension digital point cloud from a two-dimension image, and then simulate the three-dimensional structure of the physical object for further study. At present, the obtaining of three-dimension digital point cloud data is mainly based on the adaptive optics system with Shack-Hartmann sensor and phase-shifting digital holography. Referring to surface fitting, there are also many available methods such as iterated discrete fourier transform, convolution and image interpolation, linear phase retrieval. The main problems we came across in three-dimension reconstruction are the extraction of feature points and arithmetic of curve fitting. To solve such problems, we can, first of all, calculate the relevant surface normal vector information of each pixel in the light source coordinate system, then these vectors are to be converted to the coordinates of image through the coordinate conversion, so the expectant 3D point cloud get arise. Secondly, after the following procedures of de-noising, repairing, the feature points can later be selected and fitted to get the fitting function of the surface topography by means of Zernike polynomial, so as to reconstruct the determinand's three-dimensional topography. In this paper, a new kind of three-dimension reconstruction algorithm is proposed, with the assistance of which, the topography can be estimated from its grayscale at different sample points. Moreover, the previous stimulation and the experimental results prove that the new algorithm has a strong capability to fit, especially for large-scale objects .

  16. Three-dimension reconstruction based on spatial light modulator

    Science.gov (United States)

    Deng, Xuejiao; Zhang, Nanyang; Zeng, Yanan; Yin, Shiliang; Wang, Weiyu

    2011-02-01

    Three-dimension reconstruction, known as an important research direction of computer graphics, is widely used in the related field such as industrial design and manufacture, construction, aerospace, biology and so on. Via such technology we can obtain three-dimension digital point cloud from a two-dimension image, and then simulate the three-dimensional structure of the physical object for further study. At present, the obtaining of three-dimension digital point cloud data is mainly based on the adaptive optics system with Shack-Hartmann sensor and phase-shifting digital holography. Referring to surface fitting, there are also many available methods such as iterated discrete fourier transform, convolution and image interpolation, linear phase retrieval. The main problems we came across in three-dimension reconstruction are the extraction of feature points and arithmetic of curve fitting. To solve such problems, we can, first of all, calculate the relevant surface normal vector information of each pixel in the light source coordinate system, then these vectors are to be converted to the coordinates of image through the coordinate conversion, so the expectant 3D point cloud get arise. Secondly, after the following procedures of de-noising, repairing, the feature points can later be selected and fitted to get the fitting function of the surface topography by means of Zernike polynomial, so as to reconstruct the determinand's three-dimensional topography. In this paper, a new kind of three-dimension reconstruction algorithm is proposed, with the assistance of which, the topography can be estimated from its grayscale at different sample points. Moreover, the previous stimulation and the experimental results prove that the new algorithm has a strong capability to fit, especially for large-scale objects .

  17. Large-signal modulation characteristics of a GaN-based micro-LED for Gbps visible-light communication

    Science.gov (United States)

    Tian, Pengfei; Wu, Zhengyuan; Liu, Xiaoyan; Fang, Zhilai; Zhang, Shuailong; Zhou, Xiaolin; Liu, Kefu; Liu, Ming-Gang; Chen, Shu-Jhih; Lee, Chia-Yu; Cong, Chunxiao; Hu, Laigui; Qiu, Zhi-Jun; Zheng, Lirong; Liu, Ran

    2018-04-01

    The large-signal modulation characteristics of a GaN-based micro-LED have been studied for Gbps visible-light communication. With an increasing signal modulation depth the modulation bandwidth decreases, which matches up with the increase in the sum of the signal rise time and fall time. By simulating the band diagram and the carrier recombination rate of the micro-LED under large-signal modulation, carrier recombination and the carrier sweep-out effect are analyzed and found to be the dominant mechanisms behind the variation of modulation bandwidth. These results give further insight into improving the modulation bandwidth for high-speed visible-light communication.

  18. Universal holonomic single quantum gates over a geometric spin with phase-modulated polarized light.

    Science.gov (United States)

    Ishida, Naoki; Nakamura, Takaaki; Tanaka, Touta; Mishima, Shota; Kano, Hiroki; Kuroiwa, Ryota; Sekiguchi, Yuhei; Kosaka, Hideo

    2018-05-15

    We demonstrate universal non-adiabatic non-abelian holonomic single quantum gates over a geometric electron spin with phase-modulated polarized light and 93% average fidelity. This allows purely geometric rotation around an arbitrary axis by any angle defined by light polarization and phase using a degenerate three-level Λ-type system in a negatively charged nitrogen-vacancy center in diamond. Since the control light is completely resonant to the ancillary excited state, the demonstrated holonomic gate not only is fast with low power, but also is precise without the dynamical phase being subject to control error and environmental noise. It thus allows pulse shaping for further fidelity.

  19. The Spectrophotometer II: A Module on the Spectral Properties of Light. Tech Physics Series.

    Science.gov (United States)

    Frank, Nathaniel; And Others

    This module is designed to give the learner an understanding of the nature of light and how its properties are used in the design of spectrophotometers. Problems promote the use of spectrophotometers in qualitative analysis, the optical elements used in a monochromator, and the physical properties of the prism and the diffraction grating. Other…

  20. Patterning and Conductivity Modulation of Conductive Polymers by UV Light Exposure

    DEFF Research Database (Denmark)

    Edberg, Jesper; Iandolo, Donata; Brooke, Robert

    2016-01-01

    to control the conductivity in the conjugated polymer poly(3,4-ethylenedioxythiophene):tosylate by more than six orders of magnitude in addition to producing high-resolution patterns and optical gradients. The mechanism behind the modulation in the polymerization kinetics by UV light irradiation as well...

  1. A fast method for optical simulation of flood maps of light-sharing detector modules

    International Nuclear Information System (INIS)

    Shi, Han; Du, Dong; Xu, JianFeng; Moses, William W.; Peng, Qiyu

    2015-01-01

    Optical simulation of the detector module level is highly desired for Position Emission Tomography (PET) system design. Commonly used simulation toolkits such as GATE are not efficient in the optical simulation of detector modules with complicated light-sharing configurations, where a vast amount of photons need to be tracked. We present a fast approach based on a simplified specular reflectance model and a structured light-tracking algorithm to speed up the photon tracking in detector modules constructed with polished finish and specular reflector materials. We simulated conventional block detector designs with different slotted light guide patterns using the new approach and compared the outcomes with those from GATE simulations. While the two approaches generated comparable flood maps, the new approach was more than 200–600 times faster. The new approach has also been validated by constructing a prototype detector and comparing the simulated flood map with the experimental flood map. The experimental flood map has nearly uniformly distributed spots similar to those in the simulated flood map. In conclusion, the new approach provides a fast and reliable simulation tool for assisting in the development of light-sharing-based detector modules with a polished surface finish and using specular reflector materials.

  2. Method for measuring retardation of infrared wave-plate by modulated-polarized visible light

    Science.gov (United States)

    Zhang, Ying; Song, Feijun

    2012-11-01

    A new method for precisely measuring the optical phase retardation of wave-plates in the infrared spectral region is presented by using modulated-polarized visible light. An electro-optic modulator is used to accurately determine the zero point by the frequency-doubled signal of the Modulated-polarized light. A Babinet-Soleil compensator is employed to make the phase delay compensation. Based on this method, an instrument is set up to measure the retardations of the infrared wave-plates with visible region laser. Measurement results with high accuracy and sound repetition are obtained by simple calculation. Its measurement precision is less than and repetitive precision is within 0.3%.

  3. The importance of macro- versus microstructure in modulating light levels inside coral colonies

    DEFF Research Database (Denmark)

    Kaniewska, Paulina; Magnusson, Sveinn H.; Anthony, Ken R. N.

    2011-01-01

    Adjusting the light exposure and capture of their symbiotic photosynthetic dinoflagellates (genus Symbiodinium Freud.) is central to the success of reef-building corals (order Scleractinia) across high spatio-temporal variation in the light environment of coral reefs. We tested the hypothesis...... irradiances at the level of coral photosymbionts. Key index words: irradiance; morphology; photoacclimation; scale; scleractinian coral; Symbiodinium Abbreviations: a chl a, specific absorption coefficient of chl a; Ddn, diadinoxanthin; Dtn, diatoxanthin; GBR, Great Barrier Reef; GFP, green fluorescent...... that optical properties of tissues in some coral species can provide light management at the tissue scale comparable to light modulation by colony architecture in other species. We compared within-tissue scalar irradiance in two coral species from the same light habitat but with contrasting colony growth forms...

  4. Optimization of particle trapping and patterning via photovoltaic tweezers: role of light modulation and particle size

    International Nuclear Information System (INIS)

    Matarrubia, J; García-Cabañes, A; Plaza, J L; Agulló-López, F; Carrascosa, M

    2014-01-01

    The role of light modulation m and particle size on the morphology and spatial resolution of nano-particle patterns obtained by photovoltaic tweezers on Fe : LiNbO 3 has been investigated. The impact of m when using spherical as well as non-spherical (anisotropic) nano-particles deposited on the sample surface has been elucidated. Light modulation is a key parameter determining the particle profile contrast that is optimum for spherical particles and high-m values (m ∼ 1). The minimum particle periodicities reachable are also investigated obtaining periodic patterns up to 3.5 µm. This is a value at least one order of magnitude shorter than those obtained in previous reported experiments. Results are successfully explained and discussed in light of the previous reported models for photorefraction including nonlinear carrier transport and dielectrophoretic trapping. From the results, a number of rules for particle patterning optimization are derived. (paper)

  5. Pump-probe nonlinear magneto-optical rotation with frequency-modulated light

    International Nuclear Information System (INIS)

    Pustelny, S.; Gawlik, W.; Jackson Kimball, D. F.; Rochester, S. M.; Yashchuk, V. V.; Budker, D.

    2006-01-01

    Specific types of atomic coherences between Zeeman sublevels can be generated and detected using a method based on nonlinear magneto-optical rotation with frequency-modulated light. Linearly polarized, frequency-modulated light is employed to selectively generate ground-state coherences between Zeeman sublevels for which Δm=2 and Δm=4 in 85 Rb and 87 Rb atoms, and additionally Δm=6 in 85 Rb. The atomic coherences are detected with a separate, unmodulated probe light beam. Separation of the pump and probe beams enables independent investigation of the processes of creation and detection of the atomic coherences. With the present technique the transfer of the Zeeman coherences, including high-order coherences, from excited to ground state by spontaneous emission has been observed

  6. Plant experiments with light-emitting diode module in Svet space greenhouse

    Science.gov (United States)

    Ilieva, Iliyana; Ivanova, Tania; Naydenov, Yordan; Dandolov, Ivan; Stefanov, Detelin

    Light is necessary for photosynthesis and shoot orientation in the space plant growth facilities. Light modules (LM) must provide sufficient photosynthetic photon flux for optimal efficiency of photosynthetic processes and also meet the constraints for power, volume and mass. A new LM for SVET Space Greenhouse using Cree R XLamp R 7090 XR light-emitting diodes (LEDs) is developed. Three types of monochromic LEDs emitting in the red, green, and blue region of the spectrum are used. The new LM contains 36 LED spots - 30 LED spots with one red, green and blue LED and 6 LED spots with three red LEDs. DMX programming device controls the LED spots and can set 231 levels of light intensity thus achieving Photosynthetic Photon Flux Density (PPFD) in the range 0-400 µmol.m-2 .s-1 and different percentages of the red, green and blue light, depending on the experimental objectives. Two one-month experiments with "salad-type" plants - lettuce and chicory were carried at 400 µmol.m-2 .s-1 PPFD (high light - HL) and 220 µmol.m-2 .s-1 PPFD (low light - LL) and composition 70% red, 20% green and 10% blue light. In vivo modulated chlorophyll fluorescence was measured by a PAM fluorometer on leaf discs and the following parameters: effective quantum yield of Photosystem II (ΦP SII ) and non-photochemical quenching (NPQ) were calculated. Both lettuce and chicory plants grown at LL express higher photochemical activity of Photosystem II (PSII) than HL grown plants, evaluated by the actual PSII quantum yield, ΦP SII . The calculated steady state NPQ values did not differ significantly in lettuce and chicory. The rapid phase of the NPQ increase was accelerated in all studied LL leaves. In conclusion low light conditions ensured more effective functioning of PSII than HL when lettuce and chicory plants were grown at 70% red, 20% green and 10% blue light composition.

  7. Interprofessional Obstetric Ultrasound Education: Successful Development of Online Learning Modules; Case-Based Seminars; and Skills Labs for Registered and Advanced Practice Nurses, Midwives, Physicians, and Trainees.

    Science.gov (United States)

    Shaw-Battista, Jenna; Young-Lin, Nichole; Bearman, Sage; Dau, Kim; Vargas, Juan

    2015-01-01

    Ultrasound is an important aid in the clinical diagnosis and management of normal and complicated pregnancy and childbirth. The technology is widely applied to maternity care in the United States, where comprehensive standard ultrasound examinations are routine. Targeted scans are common and used for an increasing number of clinical indications due to emerging research and a greater availability of equipment with better image resolution at lower cost. These factors contribute to an increased demand for obstetric ultrasound education among students and providers of maternity care, despite a paucity of data to inform education program design and evaluation. To meet this demand, from 2012 to 2015 the University of California, San Francisco nurse-midwifery education program developed and implemented an interprofessional obstetric ultrasound course focused on clinical applications commonly managed by maternity care providers from different professions and disciplines. The course included matriculating students in nursing and medicine, as well as licensed practitioners such as registered and advanced practice nurses, midwives, and physicians and residents in obstetrics and gynecology and family medicine. After completing 10 online modules with a pre- and posttest of knowledge and interprofessional competencies related to teamwork and communication, trainees attended a case-based seminar and hands-on skills practicum with pregnant volunteers. The course aimed to establish a foundation for further supervised clinical training prior to independent practice of obstetric ultrasound. Course development was informed by professional guidelines and clinical and education research literature. This article describes the foundations, with a review of the challenges and solutions encountered in obstetric ultrasound education development and implementation. Our experience will inform educators who wish to facilitate obstetric ultrasound competency development among new and experienced

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored by Please ...

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored by Please ...

  10. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... specific content. Related Articles and Media Sonohysterography Ultrasound - Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and ...

  11. Development and utilization of liquid quartz light modulating film. Ekisho choko film no kaihatsu to riyo

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, M. (Ajinomoto Co. Inc., Tokyo (Japan))

    1992-03-01

    This paper introduces the polymer dispersed liquid crystal (PDLC) ACT'' sheet, a liquid quartz light modulating film, developed by the Ajinomoto Company in Japan. A mixture of liquid crystal and polymer precursor is sandwiched between polyethylene terephthalate films imparted with transparency conductor made of indium tin oxide (ITO), which is then polymerized by heating or irradiating ultraviolet rays to obtain a PDLC. The film has a thickness as thin as about 0.3 mm, and good processibility. The sheet uses light modulating elements functioning on scatter and permeation of light. Clarification was made on the voltage dependence of cloudiness, total light permeability, straight and parallel light permeability, the response, and the operating voltage. The system consumes small amount of power with a threshold value of about 35V, and is suitable to operate large areas when working on the utility power supply. An incident light having a high diffusion capability when the electric field is turned off exhibits a high clouding function. The system gives an excellent feel of colorlessness and transparency when the electric field is turned on. The performances in heat insulation, infrared reflection capability and noise resistance are expected to be compounded for a functional versatility. 4 refs., 6 figs., 2 tabs.

  12. A stable blue-light-derived signal modulates ultraviolet-light-induced activation of the chalcone-synthase gene in cultured parsley cells

    International Nuclear Information System (INIS)

    Ohl, S.; Hahlbrock, K.; Schäfer, E.

    1989-01-01

    Run-off transcription assays were used to demonstrate that both the ultraviolet (UV)-B and blue-light receptors control transcription rates for chalcone-synthase mRNA in the course of light-induced flavonoid synthesis in parsley (Petroselinum crispum Miller (A.W. Hill)) cell-suspension cultures. Blue and red light alone, presumably acting via a blue-light receptor and active phytochrome (far-red absorbing form) respectively, can induce accumulation of chalcone-synthase mRNA. The extent of the response is however considerably smaller than that obtained when these wavebands are applied in combination with UV light. A preirradiation with blue light strongly increases the response to a subsequent UV pulse and this modulating effect of blue light is stable for at least 20 h. The modulating effect is abolished by a UV induction but can be reestablished by a second irradiation with blue light. (author)

  13. High throughput diffractive multi-beam femtosecond laser processing using a spatial light modulator

    Energy Technology Data Exchange (ETDEWEB)

    Kuang Zheng [Laser Group, Department of Engineering, University of Liverpool Brownlow Street, Liverpool L69 3GQ (United Kingdom)], E-mail: z.kuang@liv.ac.uk; Perrie, Walter [Laser Group, Department of Engineering, University of Liverpool Brownlow Street, Liverpool L69 3GQ (United Kingdom); Leach, Jonathan [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Sharp, Martin; Edwardson, Stuart P. [Laser Group, Department of Engineering, University of Liverpool Brownlow Street, Liverpool L69 3GQ (United Kingdom); Padgett, Miles [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Dearden, Geoff; Watkins, Ken G. [Laser Group, Department of Engineering, University of Liverpool Brownlow Street, Liverpool L69 3GQ (United Kingdom)

    2008-12-30

    High throughput femtosecond laser processing is demonstrated by creating multiple beams using a spatial light modulator (SLM). The diffractive multi-beam patterns are modulated in real time by computer generated holograms (CGHs), which can be calculated by appropriate algorithms. An interactive LabVIEW program is adopted to generate the relevant CGHs. Optical efficiency at this stage is shown to be {approx}50% into first order beams and real time processing has been carried out at 50 Hz refresh rate. Results obtained demonstrate high precision surface micro-structuring on silicon and Ti6Al4V with throughput gain >1 order of magnitude.

  14. Nonlinear magneto-optical rotation with modulated light in tilted magnetic fields

    International Nuclear Information System (INIS)

    Pustelny, S.; Gawlik, W.; Rochester, S. M.; Kimball, D. F. Jackson; Yashchuk, V. V.; Budker, D.

    2006-01-01

    Larmor precession of laser-polarized atoms contained in antirelaxation-coated cells, detected via nonlinear magneto-optical rotation (NMOR), is a promising technique for a new generation of ultrasensitive atomic magnetometers. For magnetic fields directed along the light propagation direction, resonances in NMOR appear when linearly polarized light is frequency or amplitude modulated at twice the Larmor frequency. Because the frequency of these resonances depends on the magnitude but not the direction of the field, they are useful for scalar magnetometry. Additional NMOR resonances at the Larmor frequency appear when the magnetic field is tilted away from the light propagation direction in the plane defined by the light propagation and polarization vectors. These resonances, studied both experimentally and with a density matrix calculation in the present work, offer a convenient method of achieving additional information about a direction of the magnetic field

  15. Modulation of the pupil function of microscope objective lens for multifocal multi-photon microscopy using a spatial light modulator

    Science.gov (United States)

    Matsumoto, Naoya; Okazaki, Shigetoshi; Takamoto, Hisayoshi; Inoue, Takashi; Terakawa, Susumu

    2014-02-01

    We propose a method for high precision modulation of the pupil function of a microscope objective lens to improve the performance of multifocal multi-photon microscopy (MMM). To modulate the pupil function, we adopt a spatial light modulator (SLM) and place it at the conjugate position of the objective lens. The SLM can generate an arbitrary number of spots to excite the multiple fluorescence spots (MFS) at the desired positions and intensities by applying an appropriate computer-generated hologram (CGH). This flexibility allows us to control the MFS according to the photobleaching level of a fluorescent protein and phototoxicity of a specimen. However, when a large number of excitation spots are generated, the intensity distribution of the MFS is significantly different from the one originally designed due to misalignment of the optical setup and characteristics of the SLM. As a result, the image of a specimen obtained using laser scanning for the MFS has block noise segments because the SLM could not generate a uniform MFS. To improve the intensity distribution of the MFS, we adaptively redesigned the CGH based on the observed MFS. We experimentally demonstrate an improvement in the uniformity of a 10 × 10 MFS grid using a dye solution. The simplicity of the proposed method will allow it to be applied for calibration of MMM before observing living tissue. After the MMM calibration, we performed laser scanning with two-photon excitation to observe a real specimen without detecting block noise segments.

  16. Trinary Encoder, Decoder, Multiplexer and Demultiplexer Using Savart Plate and Spatial Light Modulator

    Science.gov (United States)

    Ghosh, Amal K.; Singha Roy, Souradip; Mandal, Sudipta; Basuray, Amitabha

    Optoelectronic processors have already been developed with the strong potentiality of optics in information and data processing. Encoder, Decoder, Multiplexers and Demultiplexers are the most important components in modern system designs and in communications. We have implemented the same using trinary logic gates with signed magnitude defined as Modified Trinary Number (MTN). The Spatial Light Modulator (SLM) based optoelectronic circuit is suitable for high speed data processing and communications using photon as carrier. We also presented here a possible method of implementing the same using light with photon as carrier of information. The importance of the method is that all the basic gates needed may be fabricated based on basic building block.

  17. Impact damage detection in light composite sandwich panels using piezo-based nonlinear vibro-acoustic modulations

    International Nuclear Information System (INIS)

    Pieczonka, L; Ukowski, P; Klepka, A; Staszewski, W J; Uhl, T; Aymerich, F

    2014-01-01

    The nonlinear vibro-acoustic modulation technique is used for impact damage detection in light composite sandwich panels. The method utilizes piezo-based low-frequency vibration and high-frequency ultrasonic excitations. The work presented focuses on the analysis of modulation intensity. The results show that the method can be used for impact damage detection reliably separating damage-related from vibro-acoustic modulations from other intrinsic nonlinear modulations. (paper)

  18. Differential signaling spread-spectrum modulation of the LED visible light wireless communications using a mobile-phone camera

    Science.gov (United States)

    Chen, Shih-Hao; Chow, Chi-Wai

    2015-02-01

    Visible light communication (VLC) using spread spectrum modulation (SSM) and differential signaling (DS), detected by a mobile-phone camera is proposed and demonstrated for the first time to provide high immunity to background ambient light interference. The SSM signal provides the coding gain while the DS scheme enhances the clock recovery particular under high background ambient light. Experiment results confirm the feasibility of the proposed scheme, showing that the proposed system has 6-dB gain comparing with the traditional on-off keying (OOK) modulation under background ambient light of 3000 lux. The direct incident ambient light to the mobile-phone camera is 520 lux.

  19. Gray Scale Operation Of A Multichannel Optical Convolver Using The Semetex Magnetooptic Spatial Light Modulator

    Science.gov (United States)

    Davis, Jeffrey A.; Day, Timothy; Lilly, Roger A.; Taber, Donald B.; Liu, Hua-Kuang; Davis, J. A.; Day, T.; Lilly, R. A.; Taber, D. B.; Liu, H.-K.

    1988-02-01

    We present a new multichannel optical correlator/convolver architecture which uses an acoustooptic light modulator (AOLM) for the input channel and a Semetex magnetooptic spatial light modulator (MOSLM) for the set of parallel reference channels. Details of the anamorphic optical system are discussed. Experimental results illustrate use of the system as a convolver for performing digital multiplication by analog convolution (DMAC). A limited gray scale capability for data stored by the MOSLM is demonstrated by implementing this DMAC algorithm with trinary logic. Use of the MOSLM allows the number of parallel channels for the convolver to be increased significantly compared with previously reported techniques while retaining the capability for updating both channels at high speeds.

  20. Enhancement of mosquito trapping efficiency by using pulse width modulated light emitting diodes

    Science.gov (United States)

    Liu, Yu-Nan; Liu, Yu-Jen; Chen, Yi-Chian; Ma, Hsin-Yi; Lee, Hsiao-Yi

    2017-01-01

    In this study, a light-driving bug zapper is presented for well controlling the diseases brought by insects, such as mosquitoes. In order to have the device efficient to trap the insect pests in off-grid areas, pulse width modulated light emitting diodes (PWM-LED) combined with a solar power module are proposed and implemented. With specific PWM electric signals to drive the LED, it is found that no matter what the ability of catching insects or the consumed power efficiency can be enhanced thus. It is demonstrated that 40% of the UV LED consumed power and 25.9% of the total load power consumption can be saved, and the trapped mosquitoes are about 250% increased when the PWM method is applied in the bug zapper experiments.

  1. Two spatial light modulator system for laboratory simulation of random beam propagation in random media.

    Science.gov (United States)

    Wang, Fei; Toselli, Italo; Korotkova, Olga

    2016-02-10

    An optical system consisting of a laser source and two independent consecutive phase-only spatial light modulators (SLMs) is shown to accurately simulate a generated random beam (first SLM) after interaction with a stationary random medium (second SLM). To illustrate the range of possibilities, a recently introduced class of random optical frames is examined on propagation in free space and several weak turbulent channels with Kolmogorov and non-Kolmogorov statistics.

  2. A low-voltage high-speed terahertz spatial light modulator using active metamaterial

    Directory of Open Access Journals (Sweden)

    Saroj Rout

    2016-11-01

    Full Text Available An all solid-state metamaterial based terahertz (THz spatial light modulator (SLM is presented which uses high mobility 2DEG to manipulate the metamaterial resonant frequency (0.45 THz leading to terahertz wave modulation. The 2DEG is created by embedding pseudomorphic high-electron mobility transistors in the capacitive gap of each electrical-LC resonator, allowing the charge density to be controlled with very low voltage (1 V and modulating speeds up to 10 MHz while consuming sub-milliwatt power. We have demonstrated our SLM as a 2 × 2 pixel array operating around 0.45 THz by raster scanning a 6 × 6 image of an occluded metal object behind a thick polystyrene screen using a single-pixel THz imaging setup.

  3. High modulation bandwidth of a light-emitting diode with surface plasmon coupling (Conference Presentation)

    Science.gov (United States)

    Lin, Chun-Han; Tu, Charng-Gan; Yao, Yu-Feng; Chen, Sheng-Hung; Su, Chia-Ying; Chen, Hao-Tsung; Kiang, Yean-Woei; Yang, Chih-Chung

    2017-02-01

    Besides lighting, LEDs can be used for indoor data transmission. Therefore, a large modulation bandwidth becomes an important target in the development of visible LED. In this regard, enhancing the radiative recombination rate of carriers in the quantum wells of an LED is a useful method since the modulation bandwidth of an LED is related to the carrier decay rate besides the device RC time constant To increase the carrier decay rate in an LED without sacrificing its output power, the technique of surface plasmon (SP) coupling in an LED is useful. In this paper, the increases of modulation bandwidth by reducing mesa size, decreasing active layer thickness, and inducing SP coupling in blue- and green-emitting LEDs are illustrated. The results are demonstrated by comparing three different LED surface structures, including bare p-type surface, GaZnO current spreading layer, and Ag nanoparticles (NPs) for inducing SP coupling. In a single-quantum-well, blue-emitting LED with a circular mesa of 10 microns in radius, SP coupling results in a modulation bandwidth of 528.8 MHz, which is believed to be the record-high level. A smaller RC time constant can lead to a higher modulation bandwidth. However, when the RC time constant is smaller than 0.2 ns, its effect on modulation bandwidth saturates. The dependencies of modulation bandwidth on injected current density and carrier decay time confirm that the modulation bandwidth is essentially inversely proportional to a time constant, which is inversely proportional to the square-root of carrier decay rate and injected current density.

  4. Modeling and Analysis of DIPPM: A New Modulation Scheme for Visible Light Communications

    Directory of Open Access Journals (Sweden)

    Sana Ullah Jan

    2015-01-01

    Full Text Available Visible Light Communication (VLC uses an Intensity-Modulation and Direct-Detection (IM/DD scheme to transmit data. However, the light source used in VLC systems is continuously switched on and off quickly, resulting in flickering. In addition, recent illumination systems include dimming support to allow users to dim the light sources to the desired level. Therefore, the modulation scheme for data transmission in VLC system must include flicker mitigation and dimming control capabilities. In this paper, the authors propose a Double Inverse Pulse Position Modulation (DIPPM scheme that minimizes flickering and supports a high level of dimming for the illumination sources in VLC systems. To form DIPPM, some changes are made in the symbol structure of the IPPM scheme, and a detailed explanation and mathematical model of DIPPM are given in this paper. Furthermore, both analytical and simulation results for the error performance of 2-DIPPM are compared with the performance of VPPM. Also, the communication performance of DIPPM is analyzed in terms of the normalized required power.

  5. Parameter study for polymer solar modules based on various cell lengths and light intensities

    Energy Technology Data Exchange (ETDEWEB)

    Slooff, L.H.; Burgers, A.R.; Bende, E.E.; Kroon, J.M. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands); Veenstra, S.C. [ECN Solar Energy, Solliance, High Tech Campus 5, P63, 5656AE Eindhoven (Netherlands)

    2013-10-15

    Polymer solar cells may be applied in portable electronic devices, where light intensity and spectral distribution of the illuminating source can be very different compared to outdoor applications. As the power output of solar cells depends on temperature, light intensity and spectrum, the design of the module must be optimized for the specific illumination conditions in the different applications. The interconnection area between cells in a module must be as narrow as possible to maximize the active area, also called geometrical fill factor, of the module. Laser scribing has the potential to realize this. The optimal width of the interconnection zone depends both on technological limitations, e.g. laser scribe width and the minimal distance between scribes, and electrical limitations like resistive losses. The latter depends on the generated current in the cell and thus also on illumination intensity. Besides that, also the type of junction, i.e. a single or tandem junction, will influence the optimal geometry. In this paper a calculation model is presented that can be used for electrical modeling of polymer cells and modules in order to optimize the performance for the specific illumination conditions.

  6. Analysis of the response of a photovoltaic module subjected to pulsating light of variable duty cycle

    International Nuclear Information System (INIS)

    Zuñiga-Reyes, Marco A.; Sevilla-Camacho, P.Y.; Robles-Ocampo, J.B.; Lopez-Villarea, S. A.

    2017-01-01

    The present work analyzes the time domain response of polycrystalline and amorphous silicon modules subjected to a pulsed light signal, applied under conditions of darkness and controlled temperature. The applied light has a wavelength of 625 nm, a constant power of 5 Watts, a constant frequency of 10 kHz and a variable duty cycle. The response of the modules was analyzed in both direct current (DC) and alternating current (AC). The results of the research showed differences between the waveform and the amplitude of the output voltage of each of the manufacturing technologies of the modules. To validate the obtained results, the simulation of the response of a solar cell using its equivalent circuit in CA was performed. From the experimental and simulation tests it is observed that the relation between the duty cycle and the response of the modules of different technologies can be used for the monitoring and detection of faults or for the determination of the components of the AC equivalent circuit from the solar cells. (author)

  7. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves to ... Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is safe and painless, and produces pictures ...

  8. Anisotropic Light Diffraction by Ultrasound in Crystals with Strong Acoustic Anisotropy

    Science.gov (United States)

    Voloshin, Andrey S.; Balakshy, Vladimir I.

    In modern acousto-optics, crystalline materials are used predominantly for manufacturing acousto-optic instruments. Among these materials, such crystals as paratellurite, tellurium, calomel, TAS and some others occupy a prominent place, which are distinguished by exceptionally large anisotropy of acoustic properties. In this work, the influence of acoustic beam energy walk-off on characteristics of Bragg diffraction of light is studied by the example of tellurium crystal. It is shown that the walk-off can substantially change angular and frequency ranges, resulting in their narrowing or broadening subject to position of the operating point in the Bragg angle frequency characteristic. Coefficients of broadening are introduced for characterization of this effect.

  9. Fenton Process Coupled to Ultrasound and UV Light Irradiation for the Oxidation of a Model Pollutant

    Directory of Open Access Journals (Sweden)

    Karen E. Barrera-Salgado

    2016-01-01

    Full Text Available The Fenton process coupled to photosonolysis (UV light and Us, using Fe2O3 catalyst supported on Al2O3, was used to oxidize a model pollutant like acid green 50 textile dye (AG50. Dye degradation was followed by AG50 concentration decay analyses. It was observed that parameters like iron content on a fixed amount of catalyst supporting material, catalyst annealing temperature, initial dye concentration, and the solution pH influence the overall treatment efficiency. High removal efficiencies of the model pollutant are achieved. The stability and reusability tests of the Fe2O3 catalyst show that the catalyst can be used up to three cycles achieving high discoloration. Thus, this catalyst is highly efficient for the degradation of AG50 in the Fenton process.

  10. Light intensity modulates the response of two Antarctic diatom species to ocean acidification

    Directory of Open Access Journals (Sweden)

    Jasmin Pascale Heiden

    2016-12-01

    Full Text Available It is largely unknown how rising atmospheric CO2 concentrations and changes in the upper mixed layer depth, with its subsequent effects on light availability will affect phytoplankton physiology in the Southern Ocean. Linking seasonal variations in the availability of CO2 and light to abundances and physiological traits of key phytoplankton species could aid to understand their abilities to acclimate to predicted future climatic conditions. To investigate the combined effects of CO2 and light on two ecologically relevant Antarctic diatoms (Fragilariopsis curta and Odontella weisflogii a matrix of three light intensities (LL=20, ML=200, HL=500 µmol photons m-2 s-1 and three pCO2 levels (low=180, ambient=380, high=1000 µatm was applied assessing their effects on growth, particulate organic carbon (POC fixation and photophysiology. Under ambient pCO2, POC production rates were highest already at low light in Fragilariopsis, indicating saturation of photosynthesis, while in Odontella highest rates were only reached at medium irradiances. In both species ocean acidification did not stimulate, but rather inhibited, growth and POC production under low and medium light. This effect was, however, amended under high growth irradiances. Low pCO2 levels inhibited growth and POC production in both species at low and medium light, and further decreased absETRs under high light. Our results suggest that Southern Ocean diatoms were sensitive to changes in pCO2, showing species-specific responses, which were further modulated by light intensity. The two diatom species represent distinct ecotypes and revealed discrete physiological traits that matched their seasonal occurrence with the related physical conditions in Antarctic coastal waters.

  11. A 1 MHz BW 34.2 fJ/step Continuous Time Delta Sigma Modulator With an Integrated Mixer for Cardiac Ultrasound.

    Science.gov (United States)

    Kaald, Rune; Eggen, Trym; Ytterdal, Trond

    2017-02-01

    Fully digitized 2D ultrasound transducer arrays require one ADC per channel with a beamforming architecture consuming low power. We give design considerations for per-channel digitization and beamforming, and present the design and measurements of a continuous time delta-sigma modulator (CTDSM) for cardiac ultrasound applications. By integrating a mixer into the modulator frontend, the phase and frequency of the input signal can be shifted, thereby enabling both improved conversion efficiency and narrowband beamforming. To minimize the power consumption, we propose an optimization methodology using a simulated annealing framework combined with a C++ simulator solving linear electrical networks. The 3rd order single-bit feedback type modulator, implemented in a 65 nm CMOS process, achieves an SNR/SNDR of 67.8/67.4 dB across 1 MHz bandwidth consuming 131 [Formula: see text] of power. The achieved figure of merit of 34.2 fJ/step is comparable with state-of-the-art feedforward type multi-bit designs. We further demonstrate the influence to the dynamic range when performing dynamic receive beamforming on recorded delta-sigma modulated bit-stream sequences.

  12. In Situ Caging of Biomolecules in Graphene Hybrids for Light Modulated Bioactivity.

    Science.gov (United States)

    Cheng, Gong; Han, Xiao-Hui; Hao, Si-Jie; Nisic, Merisa; Zheng, Si-Yang

    2018-01-31

    Remote and noninvasive modulation of protein activity is essential for applications in biotechnology and medicine. Optical control has emerged as the most attractive approach owing to its high spatial and temporal resolutions; however, it is challenging to engineer light responsive proteins. In this work, a near-infrared (NIR) light-responsive graphene-silica-trypsin (GST) nanoreactor is developed for modulating the bioactivity of trypsin molecules. Biomolecules are spatially confined and protected in the rationally designed compartment architecture, which not only reduces the possible interference but also boosts the bioreaction efficiency. Upon NIR irradiation, the photothermal effect of the GST nanoreactor enables the ultrafast in situ heating for remote activation and tuning of the bioactivity. We apply the GST nanoreactor for remote and ultrafast proteolysis of proteins, which remarkably enhances the proteolysis efficiency and reduces the bioreaction time from the overnight of using free trypsin to seconds. We envision that this work not only provides a promising tool of ultrafast and remotely controllable proteolysis for in vivo proteomics in study of tissue microenvironment and other biomedical applications but also paves the way for exploring smart artificial nanoreactors in biomolecular modulation to gain insight in dynamic biological transformation.

  13. Spatial light modulators for full cross-connections in optical networks

    Science.gov (United States)

    Juday, Richard D. (Inventor)

    2004-01-01

    A polarization-independent optical switch is disclosed for switching at least one incoming beam from at least one input source to at least one output drain. The switch includes a polarizing beam splitter to split each of the at least one incoming beam into a first input beam and a second input beam, wherein the first input beam and the second input beams are independently polarized; a wave plate optically coupled to the second input beam for converting the polarization of the second input beam to an appropriately polarized second input beam; a beam combiner optically coupled to the first input beam and the modified second input beam, wherein the beam combiner accepts the first input beam and the modified second input beam to produce a combined beam; the combined beam is invariant to the polarization state of the input source's polarization; and a controllable spatial light modulator optically coupled to the combined beam, wherein the combined beam is diffracted by the controllable spatial light modulator to place light at a plurality of output locations.

  14. Synergistic enhancement of micro-bubble formation in ultrasound irradiated H2O-CH3OH mixtures probed by dynamic light scattering

    International Nuclear Information System (INIS)

    Pai, M.R.; Hassan, P.A.; Bharadwaj, S.R.; Kulshreshtha, S.K.

    2008-01-01

    This report investigates the formation of micro-bubbles in water-methanol mixtures upon ultrasound irradiation and its correlation with the yield of H 2 obtained as a result of sono-chemical splitting of water. The yield of hydrogen produced by sono-chemical reaction is monitored at different compositions of water-methanol mixtures. The evidence for the formation of micro-bubbles upon ultrasound irradiation is obtained by the dynamic light scattering technique. Micro-bubble formation during ultrasound irradiation of water-methanol mixtures, their stability and size distribution, has been quantitatively estimated. The effect of composition of the water-methanol mixture and duration of irradiation on the extent of bubble formation has been inferred from the changes in the light scattering intensity and its time correlation function. Exceptional stability of micro-bubbles without any additives is observed at a certain composition of the water-methanol mixture (4:3, v/v). The extent of micro-bubbles formed in the mixture correlates well with the yield of hydrogen detected. (authors)

  15. Fault identification in crystalline silicon PV modules by complementary analysis of the light and dark current-voltage characteristics

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Hacke, Peter

    2016-01-01

    This article proposes a fault identification method, based on the complementary analysis of the light and dark current-voltage (I-V) characteristics of the photovoltaic (PV) module, to distinguish between four important degradation modes that lead to power loss in PV modules: (a) degradation of t...

  16. Prostate Ultrasound

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Prostate ultrasound, also called transrectal ultrasound, provides ...

  17. Index mismatch aberration correction over long working distances using spatial light modulation.

    Science.gov (United States)

    Gjonaj, Bergin; Johnson, Patrick; Bonn, Mischa; Domke, Katrin F

    2012-11-20

    For many microscopy applications, millimeters-long free working distances (LWD) are required. However, the high resolution and contrast of LWD objectives operated in air are lost when introducing glass and/or liquid with the sample. We propose to use spatial light modulation to correct for such beam aberrations caused by refractive index mismatches. Focusing a monochromatic laser beam with a 10 mm working distance air objective (50×, 0.5 NA) through air, glass, and water, we manage to restore a sharp, intense focus (FWHMLWD air objectives, extending their usage beyond applications in air.

  18. Hypersonic modulation of light in three-dimensional photonic and phononic band-gap materials.

    Science.gov (United States)

    Akimov, A V; Tanaka, Y; Pevtsov, A B; Kaplan, S F; Golubev, V G; Tamura, S; Yakovlev, D R; Bayer, M

    2008-07-18

    The elastic coupling between the a-SiO2 spheres composing opal films brings forth three-dimensional periodic structures which besides a photonic stop band are predicted to also exhibit complete phononic band gaps. The influence of elastic crystal vibrations on the photonic band structure has been studied by injection of coherent hypersonic wave packets generated in a metal transducer by subpicosecond laser pulses. These studies show that light with energies close to the photonic band gap can be efficiently modulated by hypersonic waves.

  19. Orthogonal decomposition of a optical random field using a spatial modulator of light of liquid crystal

    International Nuclear Information System (INIS)

    Velez Juarez, Esteban; Rodriguez Garciapinna, Jorge L.; Ostrovsky, Andrey S.

    2016-01-01

    A technique for experimental determining the coherent-mode structure of electromagnetic field is proposed. This technique is based on the coherence measurements of the field in some reference basis and represents a nontrivial vector generalization of the dual-mode field correlation method recently reported by F. Ferreira and M. Belsley. The justifiability and efficiency of the proposed technique is illustrated by an example of determining the coherent-mode structure of some specially generated and experimentally characterized secondary electromagnetic source using a spatial modulator of light of liquid crystal (SLM-LC). (Author)

  20. Assessing potential targets of calcium action in light-modulated gravitropism

    Science.gov (United States)

    Roux, S. J.

    1995-01-01

    Light, through the mediation of the pigment phytochrome, modulates the gravitropic response of the shoots and roots of many plants. The transduction of both light and gravity stimuli appears to involve Ca(2+)-regulated steps, one or more of which may represent points of intersection between the two transduction chains. To be confident that Ca2+ plays a critical role in stimulus-response coupling for gravitropism, it will be important to identify specific targets of Ca2+ action whose function can be clearly linked to the regulation of growth. Calcium typically exerts its influence on cell metabolism through binding to and activating key regulatory proteins. The three best characterized of these proteins in plants are the calmodulins, calcium-dependent protein kinases, and annexins. In this review we summarize what is known about the structure and function of these proteins and speculate on how their activation by Ca2+ could influence the differential growth response of gravitropism.

  1. Prostate Ultrasound

    Medline Plus

    Full Text Available ... ultrasound or with a rectal examination, an ultrasound-guided biopsy can be performed. This procedure involves advancing ... of the Prostate) Prostate Cancer Ultrasound- and MRI-Guided Prostate Biopsy Images related to Ultrasound - Prostate Sponsored ...

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to produce pictures of the structures and ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  3. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves to produce pictures of a man’s prostate ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  4. Ultrasound -- Pelvis

    Science.gov (United States)

    ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ... Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored ...

  5. Light Modulation and Water Splitting Enhancement Using a Composite Porous GaN Structure.

    Science.gov (United States)

    Yang, Chao; Xi, Xin; Yu, Zhiguo; Cao, Haicheng; Li, Jing; Lin, Shan; Ma, Zhanhong; Zhao, Lixia

    2018-02-14

    On the basis of the laterally porous GaN, we designed and fabricated a composite porous GaN structure with both well-ordered lateral and vertical holes. Compared to the plane GaN, the composite porous GaN structure with the combination of the vertical holes can help to reduce UV reflectance and increase the saturation photocurrent during water splitting by a factor of ∼4.5. Furthermore, we investigated the underlying mechanism for the enhancement of the water splitting performance using a finite-difference time-domain method. The results show that the well-ordered vertical holes can not only help to open the embedded pore channels to the electrolyte at both sides and reduce the migration distance of the gas bubbles during the water splitting reactions but also help to modulate the light field. Using this composite porous GaN structure, most of the incident light can be modulated and trapped into the nanoholes, and thus the electric fields localized in the lateral pores can increase dramatically as a result of the strong optical coupling. Our findings pave a new way to develop GaN photoelectrodes for highly efficient solar water splitting.

  6. A hole modulator for InGaN/GaN light-emitting diodes

    Science.gov (United States)

    Zhang, Zi-Hui; Kyaw, Zabu; Liu, Wei; Ji, Yun; Wang, Liancheng; Tan, Swee Tiam; Sun, Xiao Wei; Demir, Hilmi Volkan

    2015-02-01

    The low p-type doping efficiency of the p-GaN layer has severely limited the performance of InGaN/GaN light-emitting diodes (LEDs) due to the ineffective hole injection into the InGaN/GaN multiple quantum well (MQW) active region. The essence of improving the hole injection efficiency is to increase the hole concentration in the p-GaN layer. Therefore, in this work, we have proposed a hole modulator and studied it both theoretically and experimentally. In the hole modulator, the holes in a remote p-type doped layer are depleted by the built-in electric field and stored in the p-GaN layer. By this means, the overall hole concentration in the p-GaN layer can be enhanced. Furthermore, the hole modulator is adopted in the InGaN/GaN LEDs, which reduces the effective valance band barrier height for the p-type electron blocking layer from ˜332 meV to ˜294 meV at 80 A/cm2 and demonstrates an improved optical performance, thanks to the increased hole concentration in the p-GaN layer and thus the improved hole injection into the MQWs.

  7. A hole modulator for InGaN/GaN light-emitting diodes

    International Nuclear Information System (INIS)

    Zhang, Zi-Hui; Kyaw, Zabu; Liu, Wei; Ji, Yun; Wang, Liancheng; Tan, Swee Tiam; Sun, Xiao Wei; Demir, Hilmi Volkan

    2015-01-01

    The low p-type doping efficiency of the p-GaN layer has severely limited the performance of InGaN/GaN light-emitting diodes (LEDs) due to the ineffective hole injection into the InGaN/GaN multiple quantum well (MQW) active region. The essence of improving the hole injection efficiency is to increase the hole concentration in the p-GaN layer. Therefore, in this work, we have proposed a hole modulator and studied it both theoretically and experimentally. In the hole modulator, the holes in a remote p-type doped layer are depleted by the built-in electric field and stored in the p-GaN layer. By this means, the overall hole concentration in the p-GaN layer can be enhanced. Furthermore, the hole modulator is adopted in the InGaN/GaN LEDs, which reduces the effective valance band barrier height for the p-type electron blocking layer from ∼332 meV to ∼294 meV at 80 A/cm 2 and demonstrates an improved optical performance, thanks to the increased hole concentration in the p-GaN layer and thus the improved hole injection into the MQWs

  8. Demonstration of spatial-light-modulation-based four-wave mixing in cold atoms

    Science.gov (United States)

    Juo, Jz-Yuan; Lin, Jia-Kang; Cheng, Chin-Yao; Liu, Zi-Yu; Yu, Ite A.; Chen, Yong-Fan

    2018-05-01

    Long-distance quantum optical communications usually require efficient wave-mixing processes to convert the wavelengths of single photons. Many quantum applications based on electromagnetically induced transparency (EIT) have been proposed and demonstrated at the single-photon level, such as quantum memories, all-optical transistors, and cross-phase modulations. However, EIT-based four-wave mixing (FWM) in a resonant double-Λ configuration has a maximum conversion efficiency (CE) of 25% because of absorptive loss due to spontaneous emission. An improved scheme using spatially modulated intensities of two control fields has been theoretically proposed to overcome this conversion limit. In this study, we first demonstrate wavelength conversion from 780 to 795 nm with a 43% CE by using this scheme at an optical density (OD) of 19 in cold 87Rb atoms. According to the theoretical model, the CE in the proposed scheme can further increase to 96% at an OD of 240 under ideal conditions, thereby attaining an identical CE to that of the previous nonresonant double-Λ scheme at half the OD. This spatial-light-modulation-based FWM scheme can achieve a near-unity CE, thus providing an easy method of implementing an efficient quantum wavelength converter for all-optical quantum information processing.

  9. Optical feedback-induced light modulation for fiber-based laser ablation.

    Science.gov (United States)

    Kang, Hyun Wook

    2014-11-01

    Optical fibers have been used as a minimally invasive tool in various medical fields. However, due to excessive heat accumulation, the distal end of a fiber often suffers from severe melting or devitrification, leading to the eventual fiber failure during laser treatment. In order to minimize thermal damage at the fiber tip, an optical feedback sensor was developed and tested ex vivo. Porcine kidney tissue was used to evaluate the feasibility of optical feedback in terms of signal activation, ablation performance, and light transmission. Testing various signal thresholds demonstrated that 3 V was relatively appropriate to trigger the feedback sensor and to prevent the fiber deterioration during kidney tissue ablation. Based upon the development of temporal signal signatures, full contact mode rapidly activated the optical feedback sensor possibly due to heat accumulation. Modulated light delivery induced by optical feedback diminished ablation efficiency by 30% in comparison with no feedback case. However, long-term transmission results validated that laser ablation assisted with optical feedback was able to almost consistently sustain light delivery to the tissue as well as ablation efficiency. Therefore, an optical feedback sensor can be a feasible tool to protect optical fiber tips by minimizing debris contamination and delaying thermal damage process and to ensure more efficient and safer laser-induced tissue ablation.

  10. Increasing the efficiency of silicon heterojunction solar cells and modules by light soaking

    KAUST Repository

    Kobayashi, Eiji

    2017-06-24

    Silicon heterojunction solar cells use crystalline silicon (c-Si) wafers as optical absorbers and employ bilayers of doped/intrinsic hydrogenated amorphous silicon (a-Si:H) to form passivating contacts. Recently, we demonstrated that such solar cells increase their operating voltages and thus their conversion efficiencies during light exposure. We found that this performance increase is due to improved passivation of the a-Si:H/c-Si interface and is induced by injected charge carriers (either by light soaking or forward-voltage biasing of the device). Here, we discuss this counterintuitive behavior and establish that: (i) the performance increase is observed in solar cells as well as modules; (ii) this phenomenon requires the presence of doped a-Si:H films, but is independent from whether light is incident from the a-Si:H(p) or the a-Si:H(n) side; (iii) UV and blue photons do not play a role in this effect; (iv) the performance increase can be observed under illumination intensities as low as 20Wm (0.02-sun) and appears to be almost identical in strength when under 1-sun (1000Wm); (v) the underlying physical mechanism likely differs from annealing-induced surface passivation.

  11. A reversible conductivity modulation of azobenzene-based ionic liquids in aqueous solutions using UV/vis light.

    Science.gov (United States)

    Li, Zhiyong; Yuan, Xiaoqing; Feng, Ying; Chen, Yongkui; Zhao, Yuling; Wang, Huiyong; Xu, Qingli; Wang, Jianji

    2018-05-09

    Photo-induced conductivity modulation of stimuli-responsive materials is of great importance from the viewpoint of fundamental research and technology. In this work, 5 new kinds of azobenzene-based photo-responsive ionic liquids were synthesized and characterized, and UV/vis light modulation of their conductivity was investigated in an aqueous solution. The factors affecting the conductivity modulation of the photo-responsive fluids, such as photo-isomerization efficiency, photo-regulation aggregation, concentration and chemical structure of the ionic liquids, were examined systematically. It was found that the conductivity of the ionic liquids in water exhibited a significant increase upon UV light irradiation and the ionic liquids with a shorter alkyl spacer in the cation showed a more remarkable photo-induced conductivity enhancement with a maximum increase of 150%. In addition, the solution conductivity was restored (or very close) to the initial value upon an alternative irradiation with visible light. Thus, the solution conductivity can be modulated using alternative irradiation with UV and visible light. Although the reversible photo-isomerization of the azobenzene group under UV/vis irradiation is the origin of the conductivity modulation, the photo-regulated aggregation of the ionic liquid in water is indispensable for the maximum degree of conductivity modulation because UV irradiation can weaken, even break the aggregated cis-isomers of the ionic liquids in an aqueous solution.

  12. System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns

    Science.gov (United States)

    Hassebrook, Laurence G. (Inventor); Lau, Daniel L. (Inventor); Guan, Chun (Inventor)

    2010-01-01

    A technique, associated system and program code, for retrieving depth information about at least one surface of an object, such as an anatomical feature. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the anatomical feature; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

  13. Spatio-temporal encoding using narrow-band linear frequency modulated signals in synthetic aperture ultrasound imaging

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jensen, Jørgen Arendt

    2005-01-01

    In this paper a method for spatio-temporal encoding is presented for synthetic transmit aperture ultrasound imaging (STA). The purpose is to excite several transmitters at the same time in order to transmit more acoustic energy in every single transmission. When increasing the transmitted acousti...

  14. A multi-modal stereo microscope based on a spatial light modulator.

    Science.gov (United States)

    Lee, M P; Gibson, G M; Bowman, R; Bernet, S; Ritsch-Marte, M; Phillips, D B; Padgett, M J

    2013-07-15

    Spatial Light Modulators (SLMs) can emulate the classic microscopy techniques, including differential interference (DIC) contrast and (spiral) phase contrast. Their programmability entails the benefit of flexibility or the option to multiplex images, for single-shot quantitative imaging or for simultaneous multi-plane imaging (depth-of-field multiplexing). We report the development of a microscope sharing many of the previously demonstrated capabilities, within a holographic implementation of a stereo microscope. Furthermore, we use the SLM to combine stereo microscopy with a refocusing filter and with a darkfield filter. The instrument is built around a custom inverted microscope and equipped with an SLM which gives various imaging modes laterally displaced on the same camera chip. In addition, there is a wide angle camera for visualisation of a larger region of the sample.

  15. Efficient illumination of spatial light modulators for optical trapping and manipulation

    DEFF Research Database (Denmark)

    Bañas, Andrew Rafael; Kopylov, Oleksii; Raaby, Peter

    Energy efficiency is always desirable. This is particularly true with lasers that find many applications in research and industry. Combined with spatial light modulators (SLMs) lasers are used for optical trapping and manipulation, sorting, microscopy or biological stimulation1. Besides efficiency....... We have also shown dynamic SLM-generated patterns for materials processing and biological research. To efficiently illuminate an SLM, we used a compact pen-sized GPC-LS in place of an iris. For the same input power, hologram reconstructions are ~3x brighter or alternatively ~3x more focal spots can...... be addressed. This allows better response or increased parallel addressing for e.g. optical manipulation and sorting. Simple yet effective, a GPC-LS could save substantial power in applications that truncate lasers to a specific shape....

  16. Visible light communication using DC-biased optical filter bank multi-carrier modulation

    KAUST Repository

    Chen, Rui

    2018-03-19

    Filter bank multicarrier (FBMC) has become a promising candidate to replace conventional orthogonal frequency-division multiplexing (OFDM) scheme in 5G technology due to its better spectral confinement which results in a reduced inter-channel interference (ICI). However, the viability of using FBMC in visible light communication has not been verified. In this work we present the first experimental validation of the DC-biased optical filter bank multicarrier (DCO-FBMC) modulation scheme over a free-space optical channel. Under different receiving powers, up to three times bit error rate performance improvement has been achieved using DCO-FBMC with different overlapping factors compared to that of conventional DCO-OFDM.

  17. Modulation response, mixed-mode oscillations and chaotic spiking in quantum dot light emitting diode

    International Nuclear Information System (INIS)

    Al Husseini, Hussein B.; Al Naimee, Kais A.; Al Khursan, Amin H.; Abdalah, Sora F.; Khedir, Ali H.; Meucci, Riccardo; Arecchi, F. Tito

    2015-01-01

    In this work quantum dot light emitting diode (QD-LED) was modeled in a dimensionless rate equations system where it is not done earlier. The model was examined first under bias current without any external perturbation where it exhibits chaotic phenomena since the model has multi-degrees of freedom. Then, it is perturbed by both small signal and direct current modulations (DCM), separately. The system exhibits mixed-mode oscillations (MMOs) under DCM. This behavior was reasoned to continuous states of two dimensional wetting layer (WL) which works as a reservoir to quantum dot (QD) states. QD capture was the dominant rate controlling the dynamic behavior in QD-LED. The nonlinear dynamic behavior of our model is compared very well to the experimental observations in the QD-LED

  18. Modulating light propagation in ZnO-Cu₂O-inverse opal solar cells for enhanced photocurrents.

    Science.gov (United States)

    Yantara, Natalia; Pham, Thi Thu Trang; Boix, Pablo P; Mathews, Nripan

    2015-09-07

    The advantages of employing an interconnected periodic ZnO morphology, i.e. an inverse opal structure, in electrodeposited ZnO/Cu2O devices are presented. The solar cells are fabricated using low cost solution based methods such as spin coating and electrodeposition. The impact of inverse opal geometry, mainly the diameter and thickness, is scrutinized. By employing 3 layers of an inverse opal structure with a 300 nm pore diameter, higher short circuit photocurrents (∼84% improvement) are observed; however the open circuit voltages decrease with increasing interfacial area. Optical simulation using a finite difference time domain method shows that the inverse opal structure modulates light propagation within the devices such that more photons are absorbed close to the ZnO/Cu2O junction. This increases the collection probability resulting in improved short circuit currents.

  19. Optical Implementation Of The Hopfield Model Using A Spatial Light Modulator Discussion Of Properties And Performance

    Science.gov (United States)

    Torzynski, Marc

    1989-01-01

    In this paper we propose an optical design for implementation of neuronic Hopfield network. We describe the algorithm and its potential possibilities as associative (or content addressable) memory. We then describe the optical set (using a magneto-optic spatial light modulator) and explaning its operating mode: the binary transparency of the SLM does not allow a direct and accurate experimental realisation of the theoretical algorithm. However, there is a particular setup that can implemented it powerfully but with a reduction of the effective number of neurons. The operating speed is then evaluated from the characteristics of the SLM "Sight-Mod" manufactured by SEMETEX corp.: the maximun operating frequency seems limited by the speed of the optical valve.

  20. Efficient and accurate laser shaping with liquid crystal spatial light modulators

    Energy Technology Data Exchange (ETDEWEB)

    Maxson, Jared M.; Bartnik, Adam C.; Bazarov, Ivan V. [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States)

    2014-10-27

    A phase-only spatial light modulator (SLM) is capable of precise transverse laser shaping by either functioning as a variable phase grating or by serving as a variable mask via polarization rotation. As a phase grating, the highest accuracy algorithms, based on computer generated holograms (CGHs), have been shown to yield extended laser shapes with <10% rms error, but conversely little is known about the experimental efficiency of the method in general. In this work, we compare the experimental tradeoff between error and efficiency for both the best known CGH method and polarization rotation-based intensity masking when generating hard-edged flat top beams. We find that the masking method performs comparably with CGHs, both having rms error < 10% with efficiency > 15%. Informed by best practices for high efficiency from a SLM phase grating, we introduce an adaptive refractive algorithm which has high efficiency (92%) but also higher error (16%), for nearly cylindrically symmetric cases.

  1. Visible light communication using DC-biased optical filter bank multi-carrier modulation

    KAUST Repository

    Chen, Rui; Park, Kihong; Shen, Chao; Ng, Tien Khee; Ooi, Boon S.; Alouini, Mohamed-Slim

    2018-01-01

    Filter bank multicarrier (FBMC) has become a promising candidate to replace conventional orthogonal frequency-division multiplexing (OFDM) scheme in 5G technology due to its better spectral confinement which results in a reduced inter-channel interference (ICI). However, the viability of using FBMC in visible light communication has not been verified. In this work we present the first experimental validation of the DC-biased optical filter bank multicarrier (DCO-FBMC) modulation scheme over a free-space optical channel. Under different receiving powers, up to three times bit error rate performance improvement has been achieved using DCO-FBMC with different overlapping factors compared to that of conventional DCO-OFDM.

  2. Adaptive electron beam shaping using a photoemission gun and spatial light modulator

    Science.gov (United States)

    Maxson, Jared; Lee, Hyeri; Bartnik, Adam C.; Kiefer, Jacob; Bazarov, Ivan

    2015-02-01

    The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

  3. Development of ultrasound-assisted fluorescence imaging of indocyanine green.

    Science.gov (United States)

    Morikawa, Hiroyasu; Toyota, Shin; Wada, Kenji; Uchida-Kobayashi, Sawako; Kawada, Norifumi; Horinaka, Hiromichi

    2017-01-01

    Indocyanine green (ICG) accumulation in hepatocellular carcinoma means tumors can be located by fluorescence. However, because of light scattering, it is difficult to detect ICG fluorescence from outside the body. We propose a new fluorescence imaging method that detects changes in the intensity of ICG fluorescence by ultrasound-induced temperature changes. ICG fluorescence intensity decreases as the temperature rises. Therefore, it should theoretically be possible to detect tissue distribution of ICG using ultrasound to heat tissue, moving the point of ultrasound transmission, and monitoring changes in fluorescence intensity. A new probe was adapted for clinical application. It consisted of excitation light from a laser, fluorescence sensing through a light pipe, and heating by ultrasound. We applied the probe to bovine liver to image the accumulation of ICG. ICG emits fluorescence (820 nm) upon light irradiation (783 nm). With a rise in temperature, the fluorescence intensity of ICG decreased by 0.85 %/°C. The distribution of fluorescent ICG was detected using an ultrasonic warming method in a new integrated probe. Modulating fluorescence by changing the temperature using ultrasound can determine where ICG accumulates at a depth, highlighting its potential as a means to locate hepatocellular carcinoma.

  4. Spatial light modulator array with heat minimization and image enhancement features

    Science.gov (United States)

    Jain, Kanti [Briarcliff Manor, NY; Sweatt, William C [Albuquerque, NM; Zemel, Marc [New Rochelle, NY

    2007-01-30

    An enhanced spatial light modulator (ESLM) array, a microelectronics patterning system and a projection display system using such an ESLM for heat-minimization and resolution enhancement during imaging, and the method for fabricating such an ESLM array. The ESLM array includes, in each individual pixel element, a small pixel mirror (reflective region) and a much larger pixel surround. Each pixel surround includes diffraction-grating regions and resolution-enhancement regions. During imaging, a selected pixel mirror reflects a selected-pixel beamlet into the capture angle of a projection lens, while the diffraction grating of the pixel surround redirects heat-producing unused radiation away from the projection lens. The resolution-enhancement regions of selected pixels provide phase shifts that increase effective modulation-transfer function in imaging. All of the non-selected pixel surrounds redirect all radiation energy away from the projection lens. All elements of the ESLM are fabricated by deposition, patterning, etching and other microelectronic process technologies.

  5. Non-Contact Surface Roughness Measurement by Implementation of a Spatial Light Modulator

    Directory of Open Access Journals (Sweden)

    Laura Aulbach

    2017-03-01

    Full Text Available The surface structure, especially the roughness, has a significant influence on numerous parameters, such as friction and wear, and therefore estimates the quality of technical systems. In the last decades, a broad variety of surface roughness measurement methods were developed. A destructive measurement procedure or the lack of feasibility of online monitoring are the crucial drawbacks of most of these methods. This article proposes a new non-contact method for measuring the surface roughness that is straightforward to implement and easy to extend to online monitoring processes. The key element is a liquid-crystal-based spatial light modulator, integrated in an interferometric setup. By varying the imprinted phase of the modulator, a correlation between the imprinted phase and the fringe visibility of an interferogram is measured, and the surface roughness can be derived. This paper presents the theoretical approach of the method and first simulation and experimental results for a set of surface roughnesses. The experimental results are compared with values obtained by an atomic force microscope and a stylus profiler.

  6. Low level light in combination with metabolic modulators for effective therapy

    Science.gov (United States)

    Dong, Tingting; Zhang, Qi; Hamblin, Michael R.; Wu, Mei X.

    2015-03-01

    Vascular damage occurs frequently at the injured brain causing hypoxia and is associated with poor outcomes in the clinics. We found high levels of glycolysis, reduced ATP generation, and increased formation of reactive oxygen species (ROS) and apoptosis in neurons under hypoxia. Strikingly, these adverse events were reversed significantly by noninvasive exposure of injured brain to low-level light (LLL). LLL illumination sustained the mitochondrial membrane potential, constrained cytochrome C leakage in hypoxic cells, and protected them from apoptosis, underscoring a unique property of LLL. The effect of LLL was further bolstered by combination with metabolic substrates such as pyruvate or lactate both in vivo and in vitro. The combinational treatment retained memory and learning activities of injured mice to a normal level, whereas those treated with LLL or pyruvate alone, or sham light displayed partial or severe deficiency in these cognitive functions. In accordance with well-protected learning and memory function, the hippocampal region primarily responsible for learning and memory was completely protected by a combination of LLL and pyruvate, in marked contrast to the severe loss of hippocampal tissue due to secondary damage in control mice. These data clearly suggest that energy metabolic modulators can additively or synergistically enhance the therapeutic effect of LLL in energy-producing insufficient tissues like injured brain. Keywords:

  7. Effect of body mass index on shifts in ultrasound-based image-guided intensity-modulated radiation therapy for abdominal malignancies

    International Nuclear Information System (INIS)

    Choi, Mehee; Fuller, Clifton D.; Wang, Samuel J.; Siddiqi, Ather; Wong, Adrian; Thomas, Charles R.; Fuss, Martin

    2009-01-01

    Background and purpose: We investigated whether corrective shifts determined by daily ultrasound-based image-guidance correlate with body mass index (BMI) of patients treated with image-guided intensity-modulated radiation therapy (IG-IMRT) for abdominal malignancies. The utility of daily image-guidance, particularly for patients with BMI > 25.0, is examined. Materials and methods: Total 3162 ultrasound-directed shifts were performed in 86 patients. Direction and magnitude of shifts were correlated with pretreatment BMI. Bivariate statistical analysis and analysis of set-up correction data were performed using systematic and random error calculations. Results: Total 2040 daily alignments were performed. Average 3D vector of set-up correction for all patients was 12.1 mm/fraction. Directional and absolute shifts and 3D vector length were significantly different between BMI cohorts. 3D displacement averaged 4.9 mm/fraction and 6.8mm/fraction for BMI ≤ 25.0 and BMI > 25.0, respectively. Systematic error in all axes and 3D vector was significantly greater for BMI > 25.0. Differences in random error were not statistically significant. Conclusions: Set-up corrections derived from daily ultrasound-based IG-IMRT of abdominal tumors correlated with BMI. Daily image-guidance may improve precision of IMRT delivery with benefits assessed for the entire population, particularly patients with increased habitus. Requisite PTV margins suggested in the absence of daily image-guidance are significantly greater in patients with BMI > 25.0.

  8. Prehospital Ultrasound

    Directory of Open Access Journals (Sweden)

    Jen-Tang Sun

    2014-06-01

    Full Text Available Ultrasound is a commonly used diagnostic tool in clinical conditions. With recent developments in technology, use of portable ultrasound devices has become feasible in prehospital settings. Many studies also proved the feasibility and accuracy of prehospital ultrasound. In this article, we focus on the use of prehospital ultrasound, with emphasis on trauma and chest ultrasound.

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... a pelvic ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a special ultrasound technique that ... and processes the sounds and creates graphs or color pictures that represent the flow of blood through ...

  10. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are ... Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: pelvic ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... three types of pelvic ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams are frequently ... pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men A Doppler ultrasound exam ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... Obstetrical Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: ...

  13. Focused ultrasound in ophthalmology

    Directory of Open Access Journals (Sweden)

    Silverman RH

    2016-09-01

    Full Text Available Ronald H Silverman1,2 1Department of Ophthalmology, Columbia University Medical Center, 2F.L. Lizzi Center for Biomedical Engineering, Riverside Research, New York, NY, USA Abstract: The use of focused ultrasound to obtain diagnostically significant information about the eye goes back to the 1950s. This review describes the historical and technological development of ophthalmic ultrasound and its clinical application and impact. Ultrasound, like light, can be focused, which is crucial for formation of high-resolution, diagnostically useful images. Focused, single-element, mechanically scanned transducers are most common in ophthalmology. Specially designed transducers have been used to generate focused, high-intensity ultrasound that through thermal effects has been used to treat glaucoma (via cilio-destruction, tumors, and other pathologies. Linear and annular transducer arrays offer synthetic focusing in which precise timing of the excitation of independently addressable array elements allows formation of a converging wavefront to create a focus at one or more programmable depths. Most recently, linear array-based plane-wave ultrasound, in which the array emits an unfocused wavefront and focusing is performed solely on received data, has been demonstrated for imaging ocular anatomy and blood flow. While the history of ophthalmic ultrasound extends back over half-a-century, new and powerful technologic advances continue to be made, offering the prospect of novel diagnostic capabilities. Keywords: ophthalmic ultrasound, ultrasound biomicroscopy (UBM, high-intensity focused ultrasound (HIFU, ultrafast imaging, Doppler imaging 

  14. Light-reflection random-target method for measurement of the modulation transfer function of a digital video-camera

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Jaroslav; Jakubík, P.; Machala, L.

    2005-01-01

    Roč. 116, - (2005), s. 573-585 ISSN 0030-4026 Institutional research plan: CEZ:AV0Z10100522 Keywords : random-target measuring method * light-reflection white - noise target * digital video camera * modulation transfer function * power spectral density Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.395, year: 2005

  15. Utilization of a liquid crystal spatial light modulator in a gray scale detour phase method for Fourier holograms.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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°.

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

    Science.gov (United States)

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

    2014-11-01

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

  18. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: ...

  19. Reverse-absorbance-modulation-optical lithography for optical nanopatterning at low light levels

    Energy Technology Data Exchange (ETDEWEB)

    Majumder, Apratim, E-mail: apratim.majumder@utah.edu; Wan, Xiaowen; Masid, Farhana; Menon, Rajesh [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Pollock, Benjamin J.; Andrew, Trisha L. [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Soppera, Olivier [Mulhouse Institute for Material Sciences, CNRS LRC 7228, BP2488, Mulhouse 68200 (France)

    2016-06-15

    Absorbance-Modulation-Optical Lithography (AMOL) has been previously demonstrated to be able to confine light to deep sub-wavelength dimensions and thereby, enable patterning of features beyond the diffraction limit. In AMOL, a thin photochromic layer that converts between two states via light exposure is placed on top of the photoresist layer. The long wavelength photons render the photochromic layer opaque, while the short-wavelength photons render it transparent. By simultaneously illuminating a ring-shaped spot at the long wavelength and a round spot at the short wavelength, the photochromic layer transmits only a highly confined beam at the short wavelength, which then exposes the underlying photoresist. Many photochromic molecules suffer from a giant mismatch in quantum yields for the opposing reactions such that the reaction initiated by the absorption of the short-wavelength photon is orders of magnitude more efficient than that initiated by the absorption of the long-wavelength photon. As a result, large intensities in the ring-shaped spot are required for deep sub-wavelength nanopatterning. In this article, we overcome this problem by using the long-wavelength photons to expose the photoresist, and the short-wavelength photons to confine the “exposing” beam. Thereby, we demonstrate the patterning of features as thin as λ/4.7 (137 nm for λ = 647 nm) using extremely low intensities (4-30 W/m{sup 2}, which is 34 times lower than that required in conventional AMOL). We further apply a rigorous model to explain our experiments and discuss the scope of the reverse-AMOL process.

  20. Lighting.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    1992-09-01

    Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.

  1. Single-photon three-qubit quantum logic using spatial light modulators.

    Science.gov (United States)

    Kagalwala, Kumel H; Di Giuseppe, Giovanni; Abouraddy, Ayman F; Saleh, Bahaa E A

    2017-09-29

    The information-carrying capacity of a single photon can be vastly expanded by exploiting its multiple degrees of freedom: spatial, temporal, and polarization. Although multiple qubits can be encoded per photon, to date only two-qubit single-photon quantum operations have been realized. Here, we report an experimental demonstration of three-qubit single-photon, linear, deterministic quantum gates that exploit photon polarization and the two-dimensional spatial-parity-symmetry of the transverse single-photon field. These gates are implemented using a polarization-sensitive spatial light modulator that provides a robust, non-interferometric, versatile platform for implementing controlled unitary gates. Polarization here represents the control qubit for either separable or entangling unitary operations on the two spatial-parity target qubits. Such gates help generate maximally entangled three-qubit Greenberger-Horne-Zeilinger and W states, which is confirmed by tomographical reconstruction of single-photon density matrices. This strategy provides access to a wide range of three-qubit states and operations for use in few-qubit quantum information processing protocols.Photons are essential for quantum information processing, but to date only two-qubit single-photon operations have been realized. Here the authors demonstrate experimentally a three-qubit single-photon linear deterministic quantum gate by exploiting polarization along with spatial-parity symmetry.

  2. Holographic Fabrication of Designed Functional Defect Lines in Photonic Crystal Lattice Using a Spatial Light Modulator

    Directory of Open Access Journals (Sweden)

    Jeffrey Lutkenhaus

    2016-04-01

    Full Text Available We report the holographic fabrication of designed defect lines in photonic crystal lattices through phase engineering using a spatial light modulator (SLM. The diffracted beams from the SLM not only carry the defect’s content but also the defect related phase-shifting information. The phase-shifting induced lattice shifting in photonic lattices around the defects in three-beam interference is less than the one produced by five-beam interference due to the alternating shifting in lattice in three beam interference. By designing the defect line at a 45 degree orientation and using three-beam interference, the defect orientation can be aligned with the background photonic lattice, and the shifting is only in one side of the defect line, in agreement with the theory. Finally, a new design for the integration of functional defect lines in a background phase pattern reduces the relative phase shift of the defect and utilizes the different diffraction efficiency between the defect line and background phase pattern. We demonstrate that the desired and functional defect lattice can be registered into the background lattice through the direct imaging of designed phase patterns.

  3. PHASE QUANTIZATION STUDY OF SPATIAL LIGHT MODULATOR FOR EXTREME HIGH-CONTRAST IMAGING

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Jiangpei; Ren, Deqing, E-mail: jpdou@niaot.ac.cn, E-mail: jiangpeidou@gmail.com [Physics and Astronomy Department, California State University Northridge, 18111 Nordhoff Street, Northridge, CA 91330 (United States)

    2016-11-20

    Direct imaging of exoplanets by reflected starlight is extremely challenging due to the large luminosity ratio to the primary star. Wave-front control is a critical technique to attenuate the speckle noise in order to achieve an extremely high contrast. We present a phase quantization study of a spatial light modulator (SLM) for wave-front control to meet the contrast requirement of detection of a terrestrial planet in the habitable zone of a solar-type star. We perform the numerical simulation by employing the SLM with different phase accuracy and actuator numbers, which are related to the achievable contrast. We use an optimization algorithm to solve the quantization problems that is matched to the controllable phase step of the SLM. Two optical configurations are discussed with the SLM located before and after the coronagraph focal plane mask. The simulation result has constrained the specification for SLM phase accuracy in the above two optical configurations, which gives us a phase accuracy of 0.4/1000 and 1/1000 waves to achieve a contrast of 10{sup -10}. Finally, we have demonstrated that an SLM with more actuators can deliver a competitive contrast performance on the order of 10{sup -10} in comparison to that by using a deformable mirror.

  4. Adaptive electron beam shaping using a photoemission gun and spatial light modulator

    Directory of Open Access Journals (Sweden)

    Jared Maxson

    2015-02-01

    Full Text Available The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

  5. Two-dimensional magneto-optical light modulation in EuTiO3

    Science.gov (United States)

    Bussmann-Holder, Annette; Roleder, Krystian; Stuhlhofer, Benjamin; Logvenov, Gennady; Simon, Arndt; KöHler, Jürgen

    EuTiO3 is antiferromagnetic at low temperature, namely below TN = 5.7K. In the high temperature paramagnetic phase the strongly nonlinear coupling between the lattice and the nomnially silent Eu 4f7 spins induces magnetic correlations which become apparent in muon spin rotation experiments and more recently in birefringence measurments in an external magnetic field. It is shown here, that high quality films of insulating EuTiO3 deposited on a thin SrTiO3 substrate are versatile tools for light modulation. The operating temperature is close to room temperature and admits multiple device engineering. By using small magnetic fields the birefringence of the samples can be switched off and on. Similarly, rotation of the sample in the field can modify its birefringence Δn. In addition, Δn can be increased by a factor of 4 in very modest fields with simultaneously enhancing the operating temperature by almost 100K. The results can be understood in terms of paramagnon phonon interaction where spin activity is achieved via the local spin-phonon double-well potential.

  6. Dynamic wavefront sensing and correction with low-cost twisted nematic spatial light modulators

    International Nuclear Information System (INIS)

    Duran, Vicente; Climent, Vicent; Lancis, Jesus; Tajahuerce, Enrique; Bara, Salvador; Arines, Justo; Ares, Jorge; Andres, Pedro; Jaroszewicz, Zbigniew

    2010-01-01

    Off-the-shelf twisted nematic liquid crystal displays (TNLCDs) show some interesting features such as high spatial resolution, easy handling, wide availability, and low cost. We describe a compact adaptive optical system using just one TNLCD to measure and compensate optical aberrations. The current system operates at a frame rate of the order of 10 Hz with a four level codification scheme. Wavefront estimation is performed through conventional Hartmann-Shack sensing architecture. The system has proved to work properly with a maximum rms aberration of 0.76 microns and wavefront gradient of 50 rad/mm at a wavelength of 514 nm. These values correspond to typical aberrations found in human eyes. The key of our approach is careful characterization and optimization of the TNLCD for phase-only modulation. For this purpose, we exploit the so-called retarder-rotator approach for twisted nematic liquid crystal cells. The optimization process has been successfully applied to SLMs working either in transmissive or in reflective mode, even when light depolarization effects are observed.

  7. Multi-kW coherent combining of fiber lasers seeded with pseudo random phase modulated light

    Science.gov (United States)

    Flores, Angel; Ehrehreich, Thomas; Holten, Roger; Anderson, Brian; Dajani, Iyad

    2016-03-01

    We report efficient coherent beam combining of five kilowatt-class fiber amplifiers with a diffractive optical element (DOE). Based on a master oscillator power amplifier (MOPA) configuration, the amplifiers were seeded with pseudo random phase modulated light. Each non-polarization maintaining fiber amplifier was optically path length matched and provides approximately 1.2 kW of near diffraction-limited output power (measured M2polarization control. A low power sample of the combined beam after the DOE provided an error signal for active phase locking which was performed via Locking of Optical Coherence by Single-Detector Electronic-Frequency Tagging (LOCSET). After phase stabilization, the beams were coherently combined via the 1x5 DOE. A total combined output power of 4.9 kW was achieved with 82% combining efficiency and excellent beam quality (M2splitter loss was 5%. Similarly, losses due in part to non-ideal polarization, ASE content, uncorrelated wavefront errors, and misalignment errors contributed to the efficiency reduction.

  8. The effect of halogen light stimulation on duration of ultrasound parameters of biophysical profile: a randomized clinical trial.

    Science.gov (United States)

    Hanafi, Mohammad Ghasem; Sahraeizadeh, Aliakbar

    2018-02-22

    The objective is to assess if fetal halogen light stimulation can reduce the time needed to obtain a normal biophysical profile (BPP). Patients scheduled for a BPP and who satisfied the inclusion criteria were prospectively randomized to halogen light stimulation and no stimulation groups. The study group was exposed to handheld halogen light for 10 s whenever fetal breathing, movement, or tone was absent through the first 5 min of BPP. The time required to achieve complete BPP score was recorded. In patients with complete BPP score who had delivery within 1 week after the test, perinatal morbidity was examined. A total of 598 patients were randomized (light = 302, no light = 296). There was no difference between the two groups in terms of gestational age, maternal age, body mass index, and indication for BPP except for preterm labor (light: 9%, no light: 4%, p = 0.03). Among the patients who had a normal BPP score (n = 507), the mean (light: 7.1 ± 6 min, no light: 12.3 ± 8 min, p BPP score was significantly less in the light stimulation group than the no stimulation group. Perinatal outcomes were not different between groups who had delivery during the first week after BPP. Fetal halogen light stimulation can be utilized to reduce the time needed to complete a BPP. However, further studies should be conducted in order to determine the effect of this method on decreasing non-reassuring test results. The study was submitted to the Registry of Clinical Trials on 04/20/2017 (IRCT2017041633470N1). After IRCT registration on 06/07/2017, we recruited patients from 06/08/2017 till 10/15/2017.

  9. Lighting

    Data.gov (United States)

    Federal Laboratory Consortium — Lighting Systems Test Facilities aid research that improves the energy efficiency of lighting systems. • Gonio-Photometer: Measures illuminance from each portion of...

  10. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page This page was reviewed on ... Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding ... Images related to Ultrasound - Pelvis Sponsored by Please ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ... Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored ...

  12. Study the effects of varying interference upon the optical properties of turbid samples using NIR spatial light modulation

    Science.gov (United States)

    Shaul, Oren; Fanrazi-Kahana, Michal; Meitav, Omri; Pinhasi, Gad A.; Abookasis, David

    2018-03-01

    Optical properties of biological tissues are valuable diagnostic parameters which can provide necessary information regarding tissue state during disease pathogenesis and therapy. However, different sources of interference, such as temperature changes may modify these properties, introducing confounding factors and artifacts to data, consequently skewing their interpretation and misinforming clinical decision-making. In the current study, we apply spatial light modulation, a type of diffuse reflectance hyperspectral imaging technique, to monitor the variation in optical properties of highly scattering turbid media in the presence varying levels of the following sources of interference: scattering concentration, temperature, and pressure. Spatial near-infrared (NIR) light modulation is a wide-field, non-contact emerging optical imaging platform capable of separating the effects of tissue scattering from those of absorption, thereby accurately estimating both parameters. With this technique, periodic NIR illumination patterns at alternately low and high spatial frequencies, at six discrete wavelengths between 690 to 970 nm, were sequentially projected upon the medium while a CCD camera collects the diffusely reflected light. Data analysis based assumptions is then performed off-line to recover the medium's optical properties. We conducted a series of experiments demonstrating the changes in absorption and reduced scattering coefficients of commercially available fresh milk and chicken breast tissue under different interference conditions. In addition, information on the refractive index was study under increased pressure. This work demonstrates the utility of NIR spatial light modulation to detect varying sources of interference upon the optical properties of biological samples.

  13. Roles of Protein Kinase A and Adenylate Cyclase in Light-Modulated Cellulase Regulation in Trichoderma reesei

    Science.gov (United States)

    Schuster, André; Tisch, Doris; Seidl-Seiboth, Verena; Kubicek, Christian P.

    2012-01-01

    The cyclic AMP (cAMP) pathway represents a central signaling cascade with crucial functions in all organisms. Previous studies of Trichoderma reesei (anamorph of Hypocrea jecorina) suggested a function of cAMP signaling in regulation of cellulase gene expression. We were therefore interested in how the crucial components of this pathway, adenylate cyclase (ACY1) and cAMP-dependent protein kinase A (PKA), would affect cellulase gene expression. We found that both ACY1 and PKA catalytic subunit 1 (PKAC1) are involved in regulation of vegetative growth but are not essential for sexual development. Interestingly, our results showed considerably increased transcript abundance of cellulase genes in darkness compared to light (light responsiveness) upon growth on lactose. This effect is strongly enhanced in mutant strains lacking PKAC1 or ACY1. Comparison to the wild type showed that ACY1 has a consistently positive effect on cellulase gene expression in light and darkness, while PKAC1 influences transcript levels of cellulase genes positively in light but negatively in darkness. A function of PKAC1 in light-modulated cellulase gene regulation is also reflected by altered complex formation within the cel6a/cbh2 promoter in light and darkness and in the absence of pkac1. Analysis of transcript levels of cellulase regulator genes indicates that the regulatory output of the cAMP pathway may be established via adjustment of XYR1 abundance. Consequently, both adenylate cyclase and protein kinase A are involved in light-modulated cellulase gene expression in T. reesei and have a dampening effect on the light responsiveness of this process. PMID:22286997

  14. Light-modulated release of RFamide-like neuropeptides from nervus terminalis axon terminals in the retina of goldfish.

    Science.gov (United States)

    Fischer, A J; Stell, W K

    1997-03-01

    The nervus terminalis of teleosts, a cranial nerve anatomically associated with the olfactory system, projects to visual system targets including retina and optic tectum. It is known to contain gonadotropin-releasing hormone and RFamide-like peptides, but its function remains unknown. We have probed nervus terminalis function in goldfish by measuring peptide content in retina and tectum with a radioimmunoassay for A18Famide (neuropeptide AF; bovine morphine-modulating peptide). We found that retinal peptide content increased in the dark and decreased in the light, whereas tectal peptide content decreased in the dark and increased in the light. In addition, RFamide-like peptide content in the retina was transiently decreased by severing both olfactory tracts, increased in light-adapted eyes treated with a GABAergic agonist (isoguvacine), and decreased in dark-adapted eyes treated with GABAergic antagonists (bicuculline and picrotoxin). We also found that RFamide-like peptide release could be induced in dark-adapted isolated-superfused retinas by exposure to light or a high concentration (102.5 mM) of potassium ions. We interpret the increase and decrease in peptide content as reflecting a decrease and increase, respectively, in rate of peptide release. We propose that the release and accumulation of RFamide-like peptides in axon terminals of nervus terminalis processes in the retina are modulated primarily by neurons intrinsic to the retina and regulated by light. Peptide release appears to be inhibited tonically in the dark by GABA acting through GABAA receptors; light facilitates peptide release by disinhibition due to a reduction in GABA release. In addition, we propose that electrical signals originating outside the retina can override these intrinsic release-modulating influences.

  15. Light

    DEFF Research Database (Denmark)

    Prescott, N.B.; Kristensen, Helle Halkjær; Wathes, C.M.

    2004-01-01

    This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality......This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality...

  16. N-terminus of Cardiac Myosin Essential Light Chain Modulates Myosin Step-Size

    Science.gov (United States)

    Wang, Yihua; Ajtai, Katalin; Kazmierczak, Katarzyna; Szczesna-Cordary, Danuta; Burghardt, Thomas P.

    2016-01-01

    Muscle myosin cyclically hydrolyzes ATP to translate actin. Ventricular cardiac myosin (βmys) moves actin with three distinct unitary step-sizes resulting from its lever-arm rotation and with step-frequencies that are modulated in a myosin regulation mechanism. The lever-arm associated essential light chain (vELC) binds actin by its 43 residue N-terminal extension. Unitary steps were proposed to involve the vELC N-terminal extension with the 8 nm step engaging the vELC/actin bond facilitating an extra ~19 degrees of lever-arm rotation while the predominant 5 nm step forgoes vELC/actin binding. A minor 3 nm step is the unlikely conversion of the completed 5 to the 8 nm step. This hypothesis was tested using a 17 residue N-terminal truncated vELC in porcine βmys (Δ17βmys) and a 43 residue N-terminal truncated human vELC expressed in transgenic mouse heart (Δ43αmys). Step-size and step-frequency were measured using the Qdot motility assay. Both Δ17βmys and Δ43αmys had significantly increased 5 nm step-frequency and coincident loss in the 8 nm step-frequency compared to native proteins suggesting the vELC/actin interaction drives step-size preference. Step-size and step-frequency probability densities depend on the relative fraction of truncated vELC and relate linearly to pure myosin species concentrations in a mixture containing native vELC homodimer, two truncated vELCs in the modified homodimer, and one native and one truncated vELC in the heterodimer. Step-size and step-frequency, measured for native homodimer and at two or more known relative fractions of truncated vELC, are surmised for each pure species by using a new analytical method. PMID:26671638

  17. Study of light-absorbing crystal birefringence and electrical modulation mechanisms for coupled thermal-optical effects.

    Science.gov (United States)

    Zhou, Ji; He, Zhihong; Ma, Yu; Dong, Shikui

    2014-09-20

    This paper discusses Gaussian laser transmission in double-refraction crystal whose incident light wavelength is within its absorption wave band. Two scenarios for coupled radiation and heat conduction are considered: one is provided with an applied external electric field, the other is not. A circular heat source with a Gaussian energy distribution is introduced to present the crystal's light-absorption process. The electromagnetic field frequency domain analysis equation and energy equation are solved to simulate the phenomenon by using the finite element method. It focuses on the influence of different values such as wavelength, incident light intensity, heat transfer coefficient, ambient temperature, crystal thickness, and applied electric field strength. The results show that the refraction index of polarized light increases with the increase of crystal temperature. It decreases as the strength of the applied electric field increases if it is positive. The mechanism of electrical modulation for the thermo-optical effect is used to keep the polarized light's index of refraction constant in our simulation. The quantitative relation between thermal boundary condition and strength of applied electric field during electrical modulation is determined. Numerical results indicate a possible approach to removing adverse thermal effects such as depolarization and wavefront distortion, which are caused by thermal deposition during linear laser absorption.

  18. Summary of 2016 Light Microscopy Module (LMM) Physical Science Experiments on ISS. Update of LMM Science Experiments and Facility Capabilities

    Science.gov (United States)

    Sicker, Ronald J.; Meyer, William V.; Foster, William M.; Fletcher, William A.; Williams, Stuart J.; Lee, Chang-Soo

    2016-01-01

    This presentation will feature a series of short, entertaining, and informative videos that describe the current status and science support for the Light Microscopy Module (LMM) facility on the International Space Station. These interviews will focus on current experiments and provide an overview of future capabilities. The recently completed experiments include nano-particle haloing, 3-D self-assembly with Janus particles and a model system for nano-particle drug delivery. The videos will share perspectives from the scientists, engineers, and managers working with the NASA Light Microscopy program.

  19. Intranasal administration of dopamine attenuates unconditioned fear in that it reduces restraint-induced ultrasound vocalizations and escape from bright light.

    Science.gov (United States)

    Talbot, Teddy; Mattern, Claudia; de Souza Silva, Maria Angelica; Brandão, Marcus Lira

    2017-06-01

    Although substantial evidence suggests that dopamine (DA) enhances conditioned fear responses, few studies have examined the role of DA in unconditioned fear states. Whereas DA does not cross the blood-brain barrier, intranasally-applied dopamine reaches the brain directly via the nose-brain pathways in rodents, providing an alternative means of targeting DA receptors. Intranasal dopamine (IN-DA) has been demonstrated to bind to DA transporters and to increase extracellular DA in the striatum as well as having memory-promoting effects in rats. The purpose of this study was to examine the influence of IN-DA in three tests of fear/anxiety. The three doses of DA hydrochloride (0.03, 0.3, or 1 mg/kg) were applied in a viscous castor oil gel in a volume of 5 µl to each of both nostrils of adult Wistar rats prior to testing of (a) escape from a bright light, using a two-chamber procedure, (b) restraint-induced 22 kHz ultrasound vocalizations (USVs), and (c) exploratory behavior in the elevated plus-maze (EPM). IN-DA dose-dependently reduced escape from bright light and the number of USV responses to restraint. It had no influence on the exploratory behavior in the EPM. IN-DA application reduced escape behavior in two tests of unconditioned fear (escape from bright light and USV response to immobilization). These findings may be interpreted in light of the known antidepressant action of IN-DA and DA reuptake blockers. The results also confirm the promise of the nasal route as an alternative means for targeting the brain's dopaminergic receptors with DA.

  20. Inhibition of light modulation of chloroplast enzyme activity by sulfite. One of the lethal effects of SO/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, L E; Duggan, J X

    1977-01-01

    The capacity of a particulate pea (Pisum sativum L.) leaf chloroplast system for light-modulation of enzyme activity is diminished by brief exposure to sodium sulfite and, when intact seedlings are exposed to atmospheric SO/sub 2/, the same system is inactivated. The destructive effect of this pollutant on green plants may therefore be due to disruption of the mechanism for control of carbon dioxide fixation.

  1. Parity generator and parity checker in the modified trinary number system using savart plate and spatial light modulator

    Science.gov (United States)

    Ghosh, Amal K.

    2010-09-01

    The parity generators and the checkers are the most important circuits in communication systems. With the development of multi-valued logic (MVL), the proposed system with parity generators and checkers is the most required using the recently developed optoelectronic technology in the modified trinary number (MTN) system. This system also meets up the tremendous needs of speeds by exploiting the savart plates and spatial light modulators (SLM) in the optical tree architecture (OTA).

  2. Flexible treatment of gestational diabetes modulated on ultrasound evaluation of intrauterine growth: a controlled randomized clinical trial.

    Science.gov (United States)

    Bonomo, M; Cetin, I; Pisoni, M P; Faden, D; Mion, E; Taricco, E; Nobile de Santis, M; Radaelli, T; Motta, G; Costa, M; Solerte, L; Morabito, A

    2004-06-01

    In order to prevent abnormalities of fetal growth still characterizing pregnancies complicated by Gestational Diabetes (GDM), in the present study we evaluated a therapeutic strategy for GDM based on ultrasound (US) measurement of fetal insulin-sensitive tissues. All GDM women diagnosed before 28th week immediately started diet and self-monitoring of blood glucose; after 2 weeks they were randomized to conventional (C) or modified (M) management. In C the glycemic target (GT) was fixed at 90 fasting/120 post-prandial mg/dl; in M GT varied, according to US measurement of the Abdominal Circumference (AC) centile performed every 2 weeks: 80/100 if AC > or =75th, 100/140 if AC or =75th c. Mean metabolic data were similar in the 2 groups, but in M a tightly-optimized subgroup, resulting from the lowering of GT due to AC > or =75th, coexisted with a less-controlled one, whose higher GT was justified by ACgrowth, with clear advantages on global pregnancy outcome.

  3. Light Modulates Ocular Complications in an Albino Rat Model of Type 1 Diabetes Mellitus.

    Science.gov (United States)

    Andrawus, Elias; Veildbaum, Gizi; Zemel, Esther; Leibu, Rina; Perlman, Ido; Shehadeh, Naim

    2017-07-01

    The purpose of the study was to assess potential interactions of light exposure and hyperglycemia upon ocular complications in diabetic rats. Streptozotocin-induced (STZ-induced) diabetic rats ( N = 39) and non-diabetic rats ( N = 9) were distributed into eight groups according to the irradiance and color of the light phase during the 12/12-hour light/dark regime. Follow-up lasted 90 days and included assessment of cataract development and electroretinogram (ERG) recordings. Stress to the retina was also assessed by glial fibrillary acidic protein immunocytochemistry. Cataract development was fast in diabetic rats that were exposed to unattenuated white light or to bright colored lights during the light phase. Diabetic rats that were kept under attenuated brown or yellow light during the light phase exhibited slower rate of cataract development. Electroretinogram responses indicated very severe retinal damage in diabetic rats kept under bright colored lights in the blue-yellow range or bright white light during the light phase. Electroretinogram damage was milder in rats kept under bright red light or attenuated yellow or brown light during the light phase. Glial fibrillary acidic protein expression in retinal Müller cells was consistent with ERG assessment of retinal damage. Attenuating white light and filtering out short wavelengths have a protective effect on the eyes of diabetic rats as evident by slower rate of cataract formation and a smaller degree of retinal damage. Our findings suggest that special glasses attenuating light exposure and filtering out short wavelengths (400-530 nm) may be beneficial for diabetic patients.

  4. Modulation of recognition memory performance by light requires both melanopsin and classical photoreceptors

    Science.gov (United States)

    Tam, Shu K. E.; Hasan, Sibah; Hughes, Steven; Hankins, Mark W.; Foster, Russell G.; Bannerman, David M.

    2016-01-01

    Acute light exposure exerts various effects on physiology and behaviour. Although the effects of light on brain network activity in humans are well demonstrated, the effects of light on cognitive performance are inconclusive, with the size, as well as direction, of the effect depending on the nature of the task. Similarly, in nocturnal rodents, bright light can either facilitate or disrupt performance depending on the type of task employed. Crucially, it is unclear whether the effects of light on behavioural performance are mediated via the classical image-forming rods and cones or the melanopsin-expressing photosensitive retinal ganglion cells. Here, we investigate the modulatory effects of light on memory performance in mice using the spontaneous object recognition task. Importantly, we examine which photoreceptors are required to mediate the effects of light on memory performance. By using a cross-over design, we show that object recognition memory is disrupted when the test phase is conducted under a bright light (350 lux), regardless of the light level in the sample phase (10 or 350 lux), demonstrating that exposure to a bright light at the time of test, rather than at the time of encoding, impairs performance. Strikingly, the modulatory effect of light on memory performance is completely abolished in both melanopsin-deficient and rodless–coneless mice. Our findings provide direct evidence that melanopsin-driven and rod/cone-driven photoresponses are integrated in order to mediate the effect of light on memory performance. PMID:28003454

  5. Green light emitting nanostructures of Tb3+ doped LaOF prepared via ultrasound route applicable in display devices

    Science.gov (United States)

    Suresh, C.; Nagabhushana, H.; Basavaraj, R. B.; Prasad, B. Daruka

    2017-05-01

    For the first time Tb3+ (1-5 mol %) doped LaOF nanophosphors using Aloe vera (AV) leaves extract as bio-surfactant were synthesized by facile ultrasound supported sonochemical route at relatively high temperature (700°C) and short duration of 3h. The powder X-ray diffraction (PXRD) profiles of LaOF nanophosphors showed tetragonal structure. The morphological features of LaOF with effect of Sonication time and concentration of bio-surfactant were studied by scanning electron microscope (SEM). The particle size were estimated from transmission electron microscope (TEM) image was found to be in the range of 20-30 nm. The characteristic photoluminescence emission peaks at 487, 541, 586 and 620 nm in green region corresponding to 5D4→7Fj (j=6, 5, 4, 3) transitions of Tb3+ were observed. The LaOF: Tb3+ nanophosphors exhibit green luminescence with better chromaticity coordinates, colour purity and higher intensity under low-voltage electron beam excitation were observed by Commission International De I'Eclairage (CIE) along with colour correlated temperature (CCT). All results indicate that these obtained nanophosphors have potential applications in field emission display device.

  6. Focused ultrasound-mediated noninvasive blood-brain barrier modulation: preclinical examination of efficacy and safety in various sonication parameters.

    Science.gov (United States)

    Shin, Jaewoo; Kong, Chanho; Cho, Jae Sung; Lee, Jihyeon; Koh, Chin Su; Yoon, Min-Sik; Na, Young Cheol; Chang, Won Seok; Chang, Jin Woo

    2018-02-01

    OBJECTIVE The application of pharmacological therapeutics in neurological disorders is limited by the ability of these agents to penetrate the blood-brain barrier (BBB). Focused ultrasound (FUS) has recently gained attention for its potential application as a method for locally opening the BBB and thereby facilitating drug delivery into the brain parenchyma. However, this method still requires optimization to maximize its safety and efficacy for clinical use. In the present study, the authors examined several sonication parameters of FUS influencing BBB opening in small animals. METHODS Changes in BBB permeability were observed during transcranial sonication using low-intensity FUS in 20 adult male Sprague-Dawley rats. The authors examined the effects of FUS sonication with different sonication parameters, varying acoustic pressure, center frequency, burst duration, microbubble (MB) type, MB dose, pulse repetition frequency (PRF), and total exposure time. The focal region of BBB opening was identified by Evans blue dye. Additionally, H & E staining was used to identify blood vessel damage. RESULTS Acoustic pressure amplitude and burst duration were closely associated with enhancement of BBB opening efficiency, but these parameters were also highly correlated with tissue damage in the sonicated region. In contrast, MB types, MB dose, total exposure time, and PRF had an influence on BBB opening without conspicuous tissue damage after FUS sonication. CONCLUSIONS The study aimed to identify these influential conditions and provide safety and efficacy values for further studies. Future work based on the current results is anticipated to facilitate the implementation of FUS sonication for drug delivery in various CNS disease states in the near future.

  7. Color and illuminance level of lighting can modulate willingness to eat bell peppers.

    Science.gov (United States)

    Hasenbeck, Aimee; Cho, Sungeun; Meullenet, Jean-François; Tokar, Tonya; Yang, Famous; Huddleston, Elizabeth A; Seo, Han-Seok

    2014-08-01

    Food products are often encountered under colored lighting, particularly in restaurants and retail stores. However, relatively little attention has been paid to whether the color of ambient lighting can affect consumers' motivation for consumption. This study aimed to determine whether color (Experiment 1) and illuminance level (Experiment 2) of lighting can influence consumers' liking of appearance and their willingness to eat bell peppers. For red, green, and yellow bell peppers, yellow and blue lighting conditions consistently increased participants' liking of appearance the most and the least, respectively. Participants' willingness to consume bell peppers increased the most under yellow lighting and the least under blue lighting. In addition, a dark condition (i.e. low level of lighting illuminance) decreased liking of appearance and willingness to eat the bell peppers compared to a bright condition (i.e. high level of lighting illuminance). Our findings demonstrate that lighting color and illuminance level can influence consumers' hedonic impression and likelihood to consume bell peppers. Furthermore, the influences of color and illuminance level of lighting appear to be dependent on the surface color of bell peppers. © 2013 Society of Chemical Industry.

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... diagnose symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams ... pelvic ultrasound can help evaluate: pelvic masses pelvic pain ambiguous genitalia and anomalies of pelvic organs early ...

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... size, shape and consistency (whether the object is solid or filled with fluid). In medicine, ultrasound is ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... pictures of a man’s prostate gland and to help diagnose symptoms such as difficulty urinating or an ... Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Prostate ultrasound, ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams also help identify: ... fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) ...

  13. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... There are three types of pelvic ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams ... are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men ...

  14. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the procedure? In women, a pelvic ultrasound is most often performed to evaluate the: uterus cervix ovaries ... page How is the procedure performed? Transabdominal: For most ultrasound exams, you will be positioned lying face- ...

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... is used to evaluate the: bladder seminal vesicles prostate Transrectal ultrasound, a special study usually done to provide detailed evaluation of the prostate gland, involves inserting a specialized ultrasound transducer into ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding ... questions or for a referral to a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you ...

  17. Prostate Ultrasound

    Medline Plus

    Full Text Available ... top of page What are the benefits vs. risks? Benefits Ultrasound is widely available, easy-to-use ... procedures such as needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known ...

  18. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ovarian cysts and uterine fibroids ovarian or uterine cancers A transvaginal ultrasound is usually performed to view the endometrium (the lining of the uterus) and the ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls ...

  20. Prostate Ultrasound

    Medline Plus

    Full Text Available ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ... abnormal masses, such as tumors. In an ultrasound examination, a transducer both sends the sound waves into ...

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... needles are used to extract a sample of cells from organs for laboratory testing. Doppler ultrasound images ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no ... structure and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound ...

  3. Prostate Ultrasound

    Medline Plus

    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging uses no ionizing radiation. Ultrasound scanning ... radiation oncology provider in your community, you can search the ACR-accredited facilities database . This website does ...

  4. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound is the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn ... sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects on ...

  5. Prostate Ultrasound

    Medline Plus

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide ...

  6. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... help to distract the child and make the time pass quickly. The ultrasound exam room may have ...

  7. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ... bowel (rectum) removed during prior surgery are not good candidates for ultrasound of the prostate gland because ...

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Imaging? Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal imaging technique ... page Additional Information and Resources RTAnswers.org Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer ...

  9. Prostate Ultrasound

    Medline Plus

    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... Because ultrasound provides real-time images, it also can be used to guide procedures such as needle ...

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... of page What will I experience during and after the procedure? Ultrasound exams in which the transducer ... in the sperm or urine following the procedure. After an ultrasound examination, you should be able to ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... investigation of the uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries ... abnormal uterine bleeding Some physicians also use 3-D ultrasound or sonohysterography for patients with infertility. In ...

  12. Prostate Ultrasound

    Medline Plus

    Full Text Available ... and produces pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound ... from the probe through the gel into the body. The transducer collects the sounds that bounce back ...

  13. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... and produces pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound ... from the probe through the gel into the body. The transducer collects the sounds that bounce back ...

  14. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... object is solid or filled with fluid). In medicine, ultrasound is used to detect changes in appearance, ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Sonohysterography Ultrasound - ...

  15. Obstetrical Ultrasound

    Science.gov (United States)

    ... heartbeat can be seen as an ongoing ultrasound movie. Ultrasound devices also use Doppler, a special application ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Sonohysterography Ultrasound - ...

  17. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... menstrual problems Ultrasound exams also help identify: palpable masses such as ovarian cysts and uterine fibroids ovarian ... In children, pelvic ultrasound can help evaluate: pelvic masses pelvic pain ambiguous genitalia and anomalies of pelvic ...

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Ultrasound is safe, noninvasive, and does not use ionizing radiation. This procedure requires little to no special preparation. ... create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound is safe, noninvasive and does not use ionizing radiation. This procedure requires little to no special preparation. ... create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . ... object is solid or filled with fluid). In medicine, ultrasound is used to detect changes in appearance, ...

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... most ultrasound exams, you will be positioned lying face-up on an examination table that can be ... region of the prostate. A biopsy will add time to the procedure. If a Doppler ultrasound study ...

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams are frequently used to evaluate the ... vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men A Doppler ultrasound exam may be part of ...

  3. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... transducer sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of Pelvic Ultrasound Imaging? Ultrasound waves are ...

  4. CommWalker: correctly evaluating modules in molecular networks in light of annotation bias.

    Science.gov (United States)

    Luecken, M D; Page, M J T; Crosby, A J; Mason, S; Reinert, G; Deane, C M

    2018-03-15

    Detecting novel functional modules in molecular networks is an important step in biological research. In the absence of gold standard functional modules, functional annotations are often used to verify whether detected modules/communities have biological meaning. However, as we show, the uneven distribution of functional annotations means that such evaluation methods favor communities of well-studied proteins. We propose a novel framework for the evaluation of communities as functional modules. Our proposed framework, CommWalker, takes communities as inputs and evaluates them in their local network environment by performing short random walks. We test CommWalker's ability to overcome annotation bias using input communities from four community detection methods on two protein interaction networks. We find that modules accepted by CommWalker are similarly co-expressed as those accepted by current methods. Crucially, CommWalker performs well not only in well-annotated regions, but also in regions otherwise obscured by poor annotation. CommWalker community prioritization both faithfully captures well-validated communities and identifies functional modules that may correspond to more novel biology. The CommWalker algorithm is freely available at opig.stats.ox.ac.uk/resources or as a docker image on the Docker Hub at hub.docker.com/r/lueckenmd/commwalker/. deane@stats.ox.ac.uk. Supplementary data are available at Bioinformatics online.

  5. Light intensity modulation by coccoliths of Emiliania huxleyi as a micro-photo-regulator

    Science.gov (United States)

    Mizukawa, Yuri; Miyashita, Yuito; Satoh, Manami; Shiraiwa, Yoshihiro; Iwasaka, Masakazu

    2015-09-01

    In this study, we present experimental evidence showing that coccoliths have light-scattering anisotropy that contributes to a possible control of solar light exposure in the ocean. Changing the angle between the incident light and an applied magnetic field causes differences in the light-scattering intensities of a suspension of coccoliths isolated from Emiliania huxleyi. The magnetic field effect is induced by the diamagnetic torque force directing the coccolith radial plane perpendicular to the applied magnetic fields at 400 to 500 mT. The developed technique reveals the light-scattering anisotropies in the 3-μm-diameter floating coccoliths by orienting themselves in response to the magnetic fields. The detached coccolith scatters radially the light incident to its radial plane. The experimental results on magnetically oriented coccoliths show that an individual coccolith has a specific direction of light scattering, although the possible physiological effect of the coccolith remains for further study, focusing on the light-scattering anisotropies of coccoliths on living cells.

  6. Development and Experimental Investigations of Motion Detection Module for Smart Lighting System

    OpenAIRE

    Matveev, I.; Siemens, E.; Yurchenko, Aleksey Vasilievich; Kuznetsov, D.

    2016-01-01

    This work considers motion sensors as parts of the smart lighting system on basis of Beaglebone microcomputer. Detection system is designed for the smart lighting system. Experimental investigations of the detection system were made with different motion sensors. Based on the results comparative analysis was performed and optimal conditions for the detection system operation were found.

  7. Environmental light and time of day modulate subjective liking and wanting

    NARCIS (Netherlands)

    Itzhacki, Jacob; Te Lindert, Bart H W; van der Meijden, Wisse P; Kringelbach, Morten L; Mendoza, Jorge; Van Someren, Eus J W

    2018-01-01

    Several studies demonstrated effects of light on affect via projections from the retina of the eye to the circadian clock or via projections to areas involved in mood and reward. Few field studies investigated how naturally fluctuating light levels affect positive and negative mood in everyday life,

  8. On the evaluation of routine ultrasound screening in the third trimester for detection of light for gestational age (LGA) infants

    DEFF Research Database (Denmark)

    Secher, Niels Jørgen; Kern Hansen, P; Lenstrup, C

    1987-01-01

    % of the pregnancies. The usefulness of the screening was evaluated on the remaining 36%. An attempt to diagnose light for gestational age (LGA) infants resulted in either a low sensitivity or a low predictive value of a positive test. The late third trimester screening was more sensitive than the early, indicating......Based upon 2194 consecutive pregnancies with known gestational age, formulas for weight deviation predicted in the 32nd and 37th gestational week were estimated by multiple linear regression on the measurements of the abdominal diameter (AD) and the biparietal diameter (BPD) of the first 64...

  9. Coupling ultraviolet light and ultrasound irradiation with Conductive-Diamond Electrochemical Oxidation for the removal of progesterone

    International Nuclear Information System (INIS)

    Vidales, María J. Martín de; Barba, Silvia; Sáez, Cristina; Cañizares, Pablo; Rodrigo, Manuel A.

    2014-01-01

    Highlights: • Single sonolysis and photolysis technologies entail a slight progesterone removal and nil mineralization. • Synergistic effects of irradiating UV light and US are clearly observed in the oxidation rate. • The energy required by CDSEO and CDSPEO prevents against their application. • CDSEO mainly favors the mass transfer of organics to the conductive-diamond surface. • CDPEO promotes the formation of radicals in the bulk solution. - Abstract: This work focusses on the improvement of the efficiency of Conductive Diamond Electrochemical Oxidation (CDEO) by coupling US and UV irradiation in the degradation of progesterone from wastewater. Results show that CDEO is a promising technology for the degradation of progesterone, just the opposite of that observed for single sonolysis and photolysis technologies, which only entail a slight removal of progesterone and nil mineralization. Coupling UV light and US irradiations with CDEO seems to have a very positive effect, improving results obtained by single CDEO very significantly. Conductive Diamond Sono Electrochemical Oxidation (CDSEO) mainly seems to improve the transfer of pollutants to the conductive-diamond surface, while Conductive Diamond Photo Electrochemical Oxidation (CDPEO) seems to promote the formation of radicals from oxidants produced electrochemically. Soft oxidation conditions are obtained with the single application of both irradiation technologies, whereas an efficient mineralization is attained with CDEO, CDSEO, CDPEO and Conductive Diamond Sono-Photo Electrochemical Oxidation (CDSPEO). However, the high energy demands of US irradiation technologies advices against the use of CDSEO and CDSPEO

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

    International Nuclear Information System (INIS)

    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.

  11. Apo-bacteriophytochromes modulate bacterial photosynthesis in response to low light.

    Science.gov (United States)

    Fixen, Kathryn R; Baker, Anna W; Stojkovic, Emina A; Beatty, J Thomas; Harwood, Caroline S

    2014-01-14

    Bacteriophytochromes (BphPs) are light-sensing regulatory proteins encoded by photosynthetic and nonphotosynthetic bacteria. This protein class has been characterized structurally, but its biological activities remain relatively unexplored. Two BphPs in the anoxygenic photosynthetic bacterium Rhodopseudomonas palustris, designated regulatory proteins RpBphP2 and RpBphP3, are configured as light-regulated histidine kinases, which initiate a signal transduction system that controls expression of genes for the low light harvesting 4 (LH4) antenna complex. In vitro, RpBphP2 and RpBphP3 respond to light quality by reversible photoconversion, a property that requires the light-absorbing chromophore biliverdin. In vivo, RpBphP2 and RpBphP3 are both required for the expression of the LH4 antenna complex under anaerobic conditions, but biliverdin requires oxygen for its synthesis by heme oxygenase. On further investigation, we found that the apo-bacteriophytochrome forms of RpBphP2 and RpBphP3 are necessary and sufficient to control LH4 expression in response to light intensity in conjunction with other signal transduction proteins. One possibility is that the system senses a reduced quinone pool generated when light energy is absorbed by bacteriochlorophyll. The biliverdin-bound forms of the BphPs have the additional property of being able to fine-tune LH4 expression in response to light quality. These observations support the concept that some bacteriophytochromes can function with or without a chromophore and may be involved in regulating physiological processes not directly related to light sensing.

  12. On the evaluation of routine ultrasound screening in the third trimester for detection of light for gestational age (LGA) infants

    DEFF Research Database (Denmark)

    Secher, Niels Jørgen; Kern Hansen, P; Lenstrup, C

    1987-01-01

    Based upon 2194 consecutive pregnancies with known gestational age, formulas for weight deviation predicted in the 32nd and 37th gestational week were estimated by multiple linear regression on the measurements of the abdominal diameter (AD) and the biparietal diameter (BPD) of the first 64......% of the pregnancies. The usefulness of the screening was evaluated on the remaining 36%. An attempt to diagnose light for gestational age (LGA) infants resulted in either a low sensitivity or a low predictive value of a positive test. The late third trimester screening was more sensitive than the early, indicating...... LGA as a late phenomenon in pregnancy. Knowing the result from the late scanning, the result from the early scanning contributed almost no further information about whether the infant would be LGA at birth. Basic epidemiological characteristics of other comparable investigations on high...

  13. Impact of crystal orientation on the modulation bandwidth of InGaN/GaN light-emitting diodes

    Science.gov (United States)

    Monavarian, M.; Rashidi, A.; Aragon, A. A.; Oh, S. H.; Rishinaramangalam, A. K.; DenBaars, S. P.; Feezell, D.

    2018-01-01

    High-speed InGaN/GaN blue light-emitting diodes (LEDs) are needed for future gigabit-per-second visible-light communication systems. Large LED modulation bandwidths are typically achieved at high current densities, with reports close to 1 GHz bandwidth at current densities ranging from 5 to 10 kA/cm2. However, the internal quantum efficiency (IQE) of InGaN/GaN LEDs is quite low at high current densities due to the well-known efficiency droop phenomenon. Here, we show experimentally that nonpolar and semipolar orientations of GaN enable higher modulation bandwidths at low current densities where the IQE is expected to be higher and power dissipation is lower. We experimentally compare the modulation bandwidth vs. current density for LEDs on nonpolar (10 1 ¯ 0 ), semipolar (20 2 ¯ 1 ¯) , and polar (" separators="|0001 ) orientations. In agreement with wavefunction overlap considerations, the experimental results indicate a higher modulation bandwidth for the nonpolar and semipolar LEDs, especially at relatively low current densities. At 500 A/cm2, the nonpolar LED has a 3 dB bandwidth of ˜1 GHz, while the semipolar and polar LEDs exhibit bandwidths of 260 MHz and 75 MHz, respectively. A lower carrier density for a given current density is extracted from the RF measurements for the nonpolar and semipolar LEDs, consistent with the higher wavefunction overlaps in these orientations. At large current densities, the bandwidth of the polar LED approaches that of the nonpolar and semipolar LEDs due to coulomb screening of the polarization field. The results support using nonpolar and semipolar orientations to achieve high-speed LEDs at low current densities.

  14. Spatial light modulators and applications III; Proceedings of the Meeting, San Diego, CA, Aug. 7, 8, 1989

    Science.gov (United States)

    Efron, Uzi (Editor)

    1990-01-01

    Recent advances in the technology and applications of spatial light modulators (SLMs) are discussed in review essays by leading experts. Topics addressed include materials for SLMs, SLM devices and device technology, applications to optical data processing, and applications to artificial neural networks. Particular attention is given to nonlinear optical polymers, liquid crystals, magnetooptic SLMs, multiple-quantum-well SLMs, deformable-mirror SLMs, three-dimensional optical memories, applications of photorefractive devices to optical computing, photonic neurocomputers and learning machines, holographic associative memories, SLMs as parallel memories for optoelectronic neural networks, and coherent-optics implementations of neural-network models.

  15. Trinary flip-flops using Savart plate and spatial light modulator for optical computation in multivalued logic

    Science.gov (United States)

    Ghosh, Amal K.; Basuray, Amitabha

    2008-11-01

    The memory devices in multi-valued logic are of most significance in modern research. This paper deals with the implementation of basic memory devices in multi-valued logic using Savart plate and spatial light modulator (SLM) based optoelectronic circuits. Photons are used here as the carrier to speed up the operations. Optical tree architecture (OTA) has been also utilized in the optical interconnection network. We have exploited the advantages of Savart plates, SLMs and OTA and proposed the SLM based high speed JK, D-type and T-type flip-flops in a trinary system.

  16. Modulation of controlled-not gate using light beams carrying orbital angular momentum in a nonlinear atomic vapor

    Science.gov (United States)

    Zhang, Yan; Li, YuanYuan; Zhang, YunZhe

    2018-03-01

    We propose and experimentally demonstrate a controlled-not gate with light beams carrying orbital angular momentum (OAM) through a degenerate four-wave mixing process via a photonic band gap structure satisfying the phase-matching condition. By employing the different topological charges of a Laguerre-Gaussian beam as a qubit in this nonlinear process, the controlled-not gate with OAM can be realized. Moreover, we investigate the evolution of the controlled-not gate, which can be modulated by the frequency and the power of the incident beam, i.e., under electromagnetically induced transparency conditions. The study results are useful for applications in quantum communication and information storage.

  17. Light

    CERN Document Server

    Robertson, William C

    2003-01-01

    Why is left right and right left in the mirror? Baffled by the basics of reflection and refraction? Wondering just how the eye works? If you have trouble teaching concepts about light that you don t fully grasp yourself, get help from a book that s both scientifically accurate and entertaining with Light. By combining clear explanations, clever drawings, and activities that use easy-to-find materials, this book covers what science teachers and parents need to know to teach about light with confidence. It uses ray, wave, and particle models of light to explain the basics of reflection and refraction, optical instruments, polarization of light, and interference and diffraction. There s also an entire chapter on how the eye works. Each chapter ends with a Summary and Applications section that reinforces concepts with everyday examples. Whether you need a deeper understanding of how light bends or a good explanation of why the sky is blue, you ll find Light more illuminating and accessible than a college textbook...

  18. The effect of spatial light modulator (SLM) dependent dispersion on spatial beam shaping

    CSIR Research Space (South Africa)

    Spangenberg, D-M

    2013-08-01

    Full Text Available on the pixels between zero and two pi for a specific wavelength. It is therefore unavoidable when using the same SLM, to do beam shaping of a source which emits multiple wavelengths or a wide bandwidth, that the device will not modulate all wavelengths between...

  19. Deep modulation of second-harmonic light by wavelength detuning of a laser diode

    DEFF Research Database (Denmark)

    Christensen, Mathias; Hansen, Anders Kragh; Noordegraaf, Danny

    2017-01-01

    ) master oscillator power amplifier (MOPA) laser diode with separate electrical contacts for the MO and the PA. A modulation depth in excess of 97% from 0.1 Hz to 10 kHz is demonstrated. This is done by wavelength tuning of the laser diode using only a 40 mA adjustment of the current through the MO...

  20. Melatonin modulates monochromatic light-induced melatonin receptor expression in the hypothalamus of chicks.

    Science.gov (United States)

    Zhang, Liwei; Chen, Funing; Cao, Jing; Dong, Yulan; Wang, Zixu; Chen, Yaoxing

    2017-09-01

    To study the mechanism of the effect of monochromatic light on physiological function in chicken, a total of 192 newly hatched chicks were randomly divided into intact, sham-operated and pinealectomy groups then exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) using a light-emitting diode (LED) system for two weeks. At P14, the hypothalami were immediately collected for immunohistochemical staining of melatonin receptor subtypes (Mel1a and Mel1b) and detection of Mel1a and Mel1b expressions using RT-PCR and western blot. Immunohistochemical staining of the hypothalamus showed that the Mel1a-ir cells were distributed in the preoptic area (POA), nucleus preopticus periventricularis (POP) and suprachiasmatic nuclei (SCN), and the Mel1b-ir cells were presented in the POA and SCN. Analysis of RT-PCR and western blot showed that the mRNA and protein levels of Mel1a and Mel1b in the hypothalamus of chick exposed to GL were increased by 10.7-29.3%, 9.18-35.9% and 8.97-27.3% compared to those in the chicks exposed to WL (P=0.029-0.002), RL (P=0.027-0.001) and BL (P=0.038-0.007) in the intact group, respectively. After pinealectomy, however, these parameters decreased and there were no significant differences among the WL, RL, GL and BL groups. These findings suggested that melatonin plays a critical role in GL illumination-enhanced Mel1a and Mel1b expressions in the hypothalamus of chicks. Copyright © 2017 Elsevier GmbH. All rights reserved.

  1. Light as a central modulator of circadian rhythms, sleep and affect

    Science.gov (United States)

    LeGates, T.A.; Fernandez, D.C.; Hattar, S

    2014-01-01

    Light has profoundly influenced the evolution of life on earth. As widely appreciated, light allows us to generate images of our environment. However, light, through the atypical intrinsically photosensitive retinal ganglion cells (ipRGCs; Box 1), also influences behaviors that are essential for our health and quality of life, yet are independent of image formation. These include the synchronization of the circadian clock to the solar day, tracking of seasonal changes, and regulation of sleep. Irregular light environments lead to problems in circadian rhythms and sleep, which eventually cause mood and learning deficits. Recently, it was found that irregular light can also directly impact mood and learning without producing major disruptions in circadian rhythms and sleep. Here, we will discuss the indirect and direct influence of light on mood and learning and provide a model for how light, the circadian clock, and sleep interact to influence mood and cognitive functions. Box 1Intrinsically photosensitive retinal ganglion cells (ipRGCs)Retinal photoreceptors transduce light energy into electrical signals that initiate vision. The classical photoreceptors, rods and cones, possess modified cilia that consist of stacks of membranes in which photopigments (rhodopsin and cone opsins) are concentrated. Rods are exquisitely sensitive and are able to detect even a few photons. Rods are therefore used for night vision. Cones are less sensitive than rods and are used for day and color vision. Color vision is mediated by cone photoreceptors that express cone-opsins with sensitivity peaks at different wavelengths (colors) of light. Humans have three cone types: short, mid and long wavelength sensitive cones (for simplicity, we will refer to these as blue, green and red cones, respectively). Rods and cones relay photic information through multisynaptic pathways to retinal ganglion cells (RGCs), which innervate different areas in the brain for complex visual processing13.A

  2. Visible-Light Modulation on Lattice Dielectric Responses of a Piezo-Phototronic Soft Material.

    Science.gov (United States)

    Huang, E-Wen; Hsu, Yu-Hsiang; Chuang, Wei-Tsung; Ko, Wen-Ching; Chang, Chung-Kai; Lee, Chih-Kung; Chang, Wen-Chi; Liao, Tzu-Kang; Thong, Hao Cheng

    2015-12-16

    In situ synchrotron X-ray diffraction is used to investigate a three-way piezo-phototronic soft material. This new system is composed of a semi-crystalline poly(vinylidene fluoride-co-trifluoroethylene) piezoelectric polymer and titanium oxide nanoparticles. Under light illumination, photon-induced piezoelectric responses are nearly two times higher at both the lattice-structure and the macroscopic level than under conditions without light illumination. A mechanistic model is proposed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Light therapy modulates serotonin levels and blood flow in women with headache. A preliminary study.

    Science.gov (United States)

    Tomaz de Magalhães, Miriam; Núñez, Silvia Cristina; Kato, Ilka Tiemy; Ribeiro, Martha Simões

    2016-01-01

    In this study, we looked at the possible effects of low-level laser therapy (LLLT) on blood flow velocity, and serotonin (5-HT) and cholinesterase levels in patients with chronic headache associated with temporomandibular disorders (TMD). LLLT has been clinically applied over the past years with positive results in analgesia and without the report of any side effects. The understanding of biological mechanisms of action may improve clinical results and facilitate its indication. Ten patients presenting headache associated with TMD completed the study. An 830-nm infrared diode laser with power of 100 mW, exposure time of 34 s, and energy of 3.4 J was applied on the tender points of masseter and temporal muscle. Blood flow velocity was determined via ultrasound Doppler velocimetry before and after laser irradiation. The whole blood 5-HT and cholinesterase levels were evaluated three days before, immediately, and three days after laser irradiation. Pain score after treatment decreased to a score of 5.8 corresponding to 64% of pain reduction (P  0.05). Our findings indicated that LLLT regulates blood flow in the temporal artery after irradiation and might control 5-HT levels in patients suffering with tension-type headache associated to TMD contributing to pain relief. © 2016 by the Society for Experimental Biology and Medicine.

  4. Higher light intensity induces modulations in brain activity even during regular daytime working hours

    NARCIS (Netherlands)

    Smolders, K.C.H.J.; de Kort, Y.A.W.; Cluitmans, P.J.M.

    2016-01-01

    We investigated the effect of exposure to bright white light as compared to a commonly experienced illuminance (1000 lx vs. 200 lx at eye level, 4000 K) on electroencephalography spectral power density during daytime. Spectral power density was measured during one hour of exposure in the morning and

  5. Light management in large area thin-film silicon solar modules

    Czech Academy of Sciences Publication Activity Database

    Losio, P.A.; Caglar, O.; Cashmore, J.S.; Hötzel, J.E.; Ristau, S.; Holovský, Jakub; Remeš, Zdeněk; Sinicco, I.

    2015-01-01

    Roč. 143, Dec (2015), s. 375-385 ISSN 0927-0248 R&D Projects: GA ČR(CZ) GA14-05053S Institutional support: RVO:68378271 Keywords : micromorph * thin-film silicon solar cells * light management * ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.732, year: 2015

  6. Low light intensity and nitrogen starvation modulate the chlorophyll content of Scenedesmus dimorphus.

    Science.gov (United States)

    Ferreira, V S; Pinto, R F; Sant'Anna, C

    2016-03-01

    Chlorophyll is a photosynthetic pigment found in plants and algal organisms and is a bioproduct with human health benefits and a great potential for use in the food industry. The chlorophyll content in microalgae strains varies in response to environmental factors. In this work, we assessed the effect of nitrogen depletion and low light intensity on the chlorophyll content of the Scenedesmus dimorphus microalga. The growth of S. dimorphus under low light intensity led to a reduction in cell growth and volume as well as increased cellular chlorophyll content. Nitrogen starvation led to a reduction in cell growth and the chlorophyll content, changes in the yield and productivity of chlorophylls a and b. Transmission electron microscopy was used to investigate the ultrastructural changes in the S. dimorphus exposed to nitrogen and light deficiency. In contrast to nitrogen depletion, low light availability was an effective mean for increasing the total chlorophyll content of green microalga S. dimorphus. The findings acquired in this work are of great biotechnological importance to extend knowledge of choosing the right culture condition to stimulate the effectiveness of microalgae strains for chlorophyll production purposes. © 2015 The Society for Applied Microbiology.

  7. Modulation of fluorescence signals from biomolecules along nanowires due to interaction of light with oriented nanostructures

    DEFF Research Database (Denmark)

    Frederiksen, Rune Schøneberg; Alarcon-Llado, Esther; Madsen, Morten H.

    2015-01-01

    High aspect ratio nanostructures have gained increasing interest as highly sensitive platforms for biosensing. Here, well-defined biofunctionalized vertical indium arsenide nanowires are used to map the interaction of light with nanowires depending on their orientation and the excitation waveleng...

  8. Modulation of horizontal cell receptive fields in the light adapted goldfish retina

    NARCIS (Netherlands)

    Verweij, J.; Kamermans, M.; van den Aker, E. C.; Spekreijse, H.

    1996-01-01

    In the isolated goldfish retina, 700 nm background illumination increases the horizontal cell receptive field size, as measured with 565 nm slits of light, but decreases the receptive field size, when measured with 660 nm slits. These background-induced changes in receptive field size are absent

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  10. Unravelling the molecular basis for light modulated cellulase gene expression - the role of photoreceptors in Neurospora crassa

    Science.gov (United States)

    2012-01-01

    Background Light represents an important environmental cue, which exerts considerable influence on the metabolism of fungi. Studies with the biotechnological fungal workhorse Trichoderma reesei (Hypocrea jecorina) have revealed an interconnection between transcriptional regulation of cellulolytic enzymes and the light response. Neurospora crassa has been used as a model organism to study light and circadian rhythm biology. We therefore investigated whether light also regulates transcriptional regulation of cellulolytic enzymes in N. crassa. Results We show that the N. crassa photoreceptor genes wc-1, wc-2 and vvd are involved in regulation of cellulase gene expression, indicating that this phenomenon is conserved among filamentous fungi. The negative effect of VVD on production of cellulolytic enzymes is thereby accomplished by its role in photoadaptation and hence its function in White collar complex (WCC) formation. In contrast, the induction of vvd expression by the WCC does not seem to be crucial in this process. Additionally, we found that WC-1 and WC-2 not only act as a complex, but also have individual functions upon growth on cellulose. Conclusions Genome wide transcriptome analysis of photoreceptor mutants and evaluation of results by analysis of mutant strains identified several candidate genes likely to play a role in light modulated cellulase gene expression. Genes with functions in amino acid metabolism, glycogen metabolism, energy supply and protein folding are enriched among genes with decreased expression levels in the wc-1 and wc-2 mutants. The ability to properly respond to amino acid starvation, i. e. up-regulation of the cross pathway control protein cpc-1, was found to be beneficial for cellulase gene expression. Our results further suggest a contribution of oxidative depolymerization of cellulose to plant cell wall degradation in N. crassa. PMID:22462823

  11. Light

    CERN Document Server

    Ditchburn, R W

    1963-01-01

    This classic study, available for the first time in paperback, clearly demonstrates how quantum theory is a natural development of wave theory, and how these two theories, once thought to be irreconcilable, together comprise a single valid theory of light. Aimed at students with an intermediate-level knowledge of physics, the book first offers a historical introduction to the subject, then covers topics such as wave theory, interference, diffraction, Huygens' Principle, Fermat's Principle, and the accuracy of optical measurements. Additional topics include the velocity of light, relativistic o

  12. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... inserted into a man's rectum to view the prostate. Transvaginal ultrasound. The transducer is inserted into a ... Stenting Ultrasound-Guided Breast Biopsy Obstetric Ultrasound Ultrasound - Prostate Biopsies - Overview Images related to General Ultrasound Videos ...

  13. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce ... the limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and painless, and ...

  14. Improvement of diffraction efficiency of three-dimensional magneto-optic spatial light modulator with magnetophotonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K.; Takagi, H., E-mail: takagi@ee.tut.ac.jp; Lim, P. B.; Inoue, M., E-mail: inoue@tut.ac.jp [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441 8580 (Japan); Goto, Taichi [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441 8580 (Japan); JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Horimai, H. [HolyMine Corporation, Atsugi, Kanagawa 243 0813 (Japan); Yoshikawa, H. [Department of Computer Engineering, College of Science and Technology, Nihon University, Funabashi, Chiba 274 8501 (Japan); Bove, V. M. [MIT Media Lab, Cambridge, Massachusetts 02139 (United States)

    2016-01-11

    We have developed three-dimensional magneto-optic spatial light modulators (3D-MOSLMs) that use magnetic domains as submicron scale pixels to represent holograms. Our display system uses a submicron-scale magnetic pixel array on an amorphous TbFe film to create a wide viewing angle hologram. However, in previous work the reconstructed images had a low intensity and a low optical contrast; brightness of the reconstructed image was 4.4 × 10{sup −2 }cd/m{sup 2} with 532 nm illumination light at 10.8 mW/cm{sup 2}, while display standard ISO13406 recommends 100 cd/m{sup 2} or more. In this paper, we describe our development of a 3D-MOSLM composed of an artificial magnetic lattice structure of magnetophotonic crystals (MPCs). The MPCs enhance the diffraction efficiency of reconstructed 3D images and reduce the power consumption for controlling the magnetic pixels by a light localization effect. We demonstrate reconstructed 3D images using the MPC and show significant brightness improvement.

  15. In situ observation of modulated light emission of fiber fuse synchronized with void train over hetero-core splice point.

    Directory of Open Access Journals (Sweden)

    Shin-ichi Todoroki

    Full Text Available BACKGROUND: Fiber fuse is a process of optical fiber destruction under the action of laser radiation, found 20 years ago. Once initiated, opical discharge runs along the fiber core region to the light source and leaves periodic voids whose shape looks like a bullet pointing the direction of laser beam. The relation between damage pattern and propagation mode of optical discharge is still unclear even after the first in situ observation three years ago. METHODOLOGY/PRINCIPAL FINDINGS: Fiber fuse propagation over hetero-core splice point (Corning SMF-28e and HI 1060 was observed in situ. Sequential photographs obtained at intervals of 2.78 micros recorded a periodic emission at the tail of an optical discharge pumped by 1070 nm and 9 W light. The signal stopped when the discharge ran over the splice point. The corresponding damage pattern left in the fiber core region included a segment free of periodicity. CONCLUSIONS: The spatial modulation pattern of the light emission agreed with the void train formed over the hetero-core splice point. Some segments included a bullet-shaped void pointing in the opposite direction to the laser beam propagation although the sequential photographs did not reveal any directional change in the optical discharge propagation.

  16. Room-temperature Coulomb staircase in semiconducting InP nanowires modulated with light illumination.

    Science.gov (United States)

    Yamada, Toshishige; Yamada, Hidenori; Lohn, Andrew J; Kobayashi, Nobuhiko P

    2011-02-04

    Detailed electron transport analysis is performed for an ensemble of conical indium phosphide nanowires bridging two hydrogenated n(+)-silicon electrodes. The current-voltage (I-V) characteristics exhibit a Coulomb staircase in the dark with a period of ∼ 1 V at room temperature. The staircase is found to disappear under light illumination. This observation can be explained by assuming the presence of a tiny Coulomb island, and its existence is possible due to the large surface depletion region created within contributing nanowires. Electrons tunnel in and out of the Coulomb island, resulting in the Coulomb staircase I-V. Applying light illumination raises the electron quasi-Fermi level and the tunneling barriers are buried, causing the Coulomb staircase to disappear.

  17. Light modulation in phase change disordered metamaterial - A smart cermet concept

    OpenAIRE

    Kumar , Sunil; Maury , Francis; Bahlawane , Naoufal

    2017-01-01

    International audience; Cermet coatings are popular solar selective absorbers as they allow capturing most of the solar energywhile minimising radiative losses. Embedded metallic nanoparticles in dielectric matrices promotemultiple internal reflection of light and provide an overall low emissivity. VO2 in the metamaterial stateis regarded in this study as a responsive mixed phase comprising metallic rutile VO2 inclusions insemiconducting monoclinic VO2 phase mimicking cermet. The smart cermet...

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... be able to give a clearer picture of soft tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may be repeated as often as is necessary if medically indicated. Ultrasound provides real-time imaging, making it a good tool for guiding ...

  19. Prostate Ultrasound

    Science.gov (United States)

    ... be able to give a clearer picture of soft tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may be repeated as often as is necessary if medically indicated. Ultrasound provides real-time imaging, making it a good tool for guiding ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to ...

  1. Interventional ultrasound

    International Nuclear Information System (INIS)

    VanSonnenberg, E.

    1987-01-01

    This book contains 12 chapters and several case studies. Some of the chapter titles are: The Interplay of Ultrasound and Computed Tomography in the Planning and Execution of Interventional Procedures: Ulltrasound Guided Biopsy; Interventioal Genitourinary Sonography; Diagnosis and Treatment of Pericardial Effusion Using Ultrasonic Guidance; and New Ultrasound-Guided Interventional Procedures--Cholecystostomy, Pancreatography, Gastrostomy

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging ...

  3. Prostate Ultrasound

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of ...

  4. Ultrasound stethoscopy

    NARCIS (Netherlands)

    E.C. Vourvouri (Eleni)

    2002-01-01

    textabstractIn this thesis we repmi the many evaluation studies with the hand-held ultrasound device in the assessment of different cardiac pathologies and in different clinical settings. The reason for using the tetm "ultrasound stethoscopy" is that these devices are augmenting our

  5. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not use any ionizing radiation. Ultrasound scanning gives a clear picture of soft tissues that do not show up well on ...

  6. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the best way to see if treatment is working or if a finding is stable or changed over time. top of page What are the benefits vs. risks? Benefits Ultrasound is widely available, easy-to-use and less expensive than other imaging methods. Ultrasound imaging uses ...

  7. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... blood test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide ...

  8. Ultrasound Imaging Initiative

    Science.gov (United States)

    2003-01-01

    texture mapping hardware," IEEE Tranactions on Information Technology in Biomedicine, Submitted. [14] C.R. Castro Pareja , J.M. Jagadeesh and R. Shekhar...modulation in real-time three-dimensional sparse synthetic aperture ultrasound imaging systems "* Carlos R. Castro Pareja , Masters of Science, The Ohio...C.R. Castro Pareja , "An architecture for real-time image registration," M.S. Thesis, The Ohio State University, March 2002. 14. C.R. Castro Pareja , R

  9. Simulating atmospheric turbulence using a phase-only spatial light modulator

    CSIR Research Space (South Africa)

    Burger, L

    2008-04-01

    Full Text Available is zero and the outer scale is infinity. These assumptions lead to a well-defined distribution for the randomness in the refractive index of the atmosphere, which can be applied in the laboratory, giving a good approximation for a real atmosphere.1.... There are two basic aims: first, to expound on the steps required to actually simulate atmospheric turbulence in the laboratory, and second, to point out some of the limitations in using spatial light modula- Research Articles South African Journal of Science...

  10. Modulating emission intensity of GaN-based green light emitting diodes on c-plane sapphire

    International Nuclear Information System (INIS)

    Du, Chunhua; Ma, Ziguang; Zhou, Junming; Lu, Taiping; Jiang, Yang; Jia, Haiqiang; Liu, Wuming; Chen, Hong

    2014-01-01

    The asymmetric dual-wavelength (green/blue) coupled InGaN/GaN multiple quantum wells were proposed to modulate the green emission intensity. Electroluminescent measurements demonstrate the conspicuous increment of the green light intensity by decreasing the coupled barrier thickness. This was partly attributed to capture of more carriers when holes tunnel across the thinner barrier from the blue quantum wells, as a hole reservoir, to the green quantum wells. While lower effective barrier height of the blue quantum wells benefits improved hole transportation from p-GaN to the active region. Efficiency droop of the green quantum wells was partially alleviated due to the enhanced injection efficiency of holes

  11. High-efficiency and flexible generation of vector vortex optical fields by a reflective phase-only spatial light modulator.

    Science.gov (United States)

    Cai, Meng-Qiang; Wang, Zhou-Xiang; Liang, Juan; Wang, Yan-Kun; Gao, Xu-Zhen; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2017-08-01

    The scheme for generating vector optical fields should have not only high efficiency but also flexibility for satisfying the requirements of various applications. However, in general, high efficiency and flexibility are not compatible. Here we present and experimentally demonstrate a solution to directly, flexibly, and efficiently generate vector vortex optical fields (VVOFs) with a reflective phase-only liquid crystal spatial light modulator (LC-SLM) based on optical birefringence of liquid crystal molecules. To generate the VVOFs, this approach needs in principle only a half-wave plate, an LC-SLM, and a quarter-wave plate. This approach has some advantages, including a simple experimental setup, good flexibility, and high efficiency, making the approach very promising in some applications when higher power is need. This approach has a generation efficiency of 44.0%, which is much higher than the 1.1% of the common path interferometric approach.

  12. Ultra-low power anti-crosstalk collision avoidance light detection and ranging using chaotic pulse position modulation approach

    International Nuclear Information System (INIS)

    Hao Jie; Gong Ma-li; Du Peng-fei; Lu Bao-jie; Zhang Fan; Zhang Hai-tao; Fu Xing

    2016-01-01

    A novel concept of collision avoidance single-photon light detection and ranging (LIDAR) for vehicles has been demonstrated, in which chaotic pulse position modulation is applied on the transmitted laser pulses for robust anti-crosstalk purposes. Besides, single-photon detectors (SPD) and time correlated single photon counting techniques are adapted, to sense the ultra-low power used for the consideration of compact structure and eye safety. Parameters including pulse rate, discrimination threshold, and number of accumulated pulses have been thoroughly analyzed based on the detection requirements, resulting in specified receiver operating characteristics curves. Both simulation and indoor experiments were performed to verify the excellent anti-crosstalk capability of the presented collision avoidance LIDAR despite ultra-low transmitting power. (paper)

  13. Investigation of effective base transit time and current gain modulation of light-emitting transistors under different ambient temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hao-Hsiang; Tu, Wen-Chung; Wang, Hsiao-Lun [Graduate Institute of Photonics and Optoelectronics, National Taiwan University, 1, Roosevelt Road, Sec. 4, Taipei 106, Taiwan (China); Wu, Chao-Hsin, E-mail: chaohsinwu@ntu.edu.tw [Graduate Institute of Photonics and Optoelectronics, National Taiwan University, 1, Roosevelt Road, Sec. 4, Taipei 106, Taiwan (China); Graduate Institute of Electronics Engineering, National Taiwan University, 1, Roosevelt Road, Sec. 4, Taipei106, Taiwan (China)

    2014-11-03

    In this report, the modulation of current gain of InGaP/GaAs light-emitting transistors under different ambient temperatures are measured and analyzed using thermionic emission model of quantum well embedded in the transistor base region. Minority carriers captured by quantum wells gain more energy at high temperatures and escape from quantum wells resulting in an increase of current gain and lower optical output, resulting in different I-V characteristics from conventional heterojunction bipolar transistors. The effect of the smaller thermionic lifetime thus reduces the effective base transit time of transistors at high temperatures. The unique current gain enhancement of 27.61% is achieved when operation temperature increase from 28 to 85 °C.

  14. Schottky junctions on perovskite single crystals: light-modulated dielectric constant and self-biased photodetection

    KAUST Repository

    Shaikh, Parvez Abdul Ajij

    2016-08-16

    Schottky junctions formed between semiconductors and metal contacts are ubiquitous in modern electronic and optoelectronic devices. Here we report on the physical properties of Schottky-junctions formed on hybrid perovskite CH3NH3PbBr3 single crystals. It is found that light illumination can significantly increase the dielectric constant of perovskite junctions by 2300%. Furthermore, such Pt/perovskite junctions are used to fabricate self-biased photodetectors. A photodetectivity of 1.4 × 1010 Jones is obtained at zero bias, which increases to 7.1 × 1011 Jones at a bias of +3 V, and the photodetectivity remains almost constant in a wide range of light intensity. These devices also exhibit fast responses with a rising time of 70 μs and a falling time of 150 μs. As a result of the high crystal quality and low defect density, such single-crystal photodetectors show stable performance after storage in air for over 45 days. Our results suggest that hybrid perovskite single crystals provide a new platform to develop promising optoelectronic applications. © 2016 The Royal Society of Chemistry.

  15. Multimodal stimulation of Colorado potato beetle reveals modulation of pheromone response by yellow light.

    Directory of Open Access Journals (Sweden)

    Fernando Otálora-Luna

    Full Text Available Orientation of insects to host plants and conspecifics is the result of detection and integration of chemical and physical cues present in the environment. Sensory organs have evolved to be sensitive to important signals, providing neural input for higher order multimodal processing and behavioral output. Here we report experiments to determine decisions made by Colorado potato beetle (CPB, Leptinotarsa decemlineata, in response to isolated stimuli and multimodal combinations of signals on a locomotion compensator. Our results show that in complete darkness and in the absence of other stimuli, pheromonal stimulation increases attraction behavior of CPB as measured in oriented displacement and walking speed. However, orientation to the pheromone is abolished when presented with the alternative stimulation of a low intensity yellow light in a dark environment. The ability of the pheromone to stimulate these diurnal beetles in the dark in the absence of other stimuli is an unexpected but interesting observation. The predominance of the phototactic response over that to pheromone when low intensity lights were offered as choices seems to confirm the diurnal nature of the insect. The biological significance of the response to pheromone in the dark is unclear. The phototactic response will play a key role in elucidating multimodal stimulation in the host-finding process of CPB, and perhaps other insects. Such information might be exploited in the design of applications to attract and trap CPB for survey or control purposes and other insect pests using similar orientation mechanisms.

  16. Infrared to visible image up-conversion using optically addressed spatial light modulator utilizing liquid crystal and InGaAs photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Solodar, A., E-mail: asisolodar@gmail.com; Arun Kumar, T.; Sarusi, G.; Abdulhalim, I. [Department of Electro-Optics Engineering and The Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)

    2016-01-11

    Combination of InGaAs/InP heterojunction photodetector with nematic liquid crystal (LC) as the electro-optic modulating material for optically addressed spatial light modulator for short wavelength infra-red (SWIR) to visible light image conversion was designed, fabricated, and tested. The photodetector layer is composed of 640 × 512 photodiodes array based on heterojunction InP/InGaAs having 15 μm pitch on InP substrate and with backside illumination architecture. The photodiodes exhibit extremely low, dark current at room temperature, with optimum photo-response in the SWIR region. The photocurrent generated in the heterojunction, due to the SWIR photons absorption, is drifted to the surface of the InP, thus modulating the electric field distribution which modifies the orientation of the LC molecules. This device can be attractive for SWIR to visible image upconversion, such as for uncooled night vision goggles under low ambient light conditions.

  17. Multi-point laser spark generation for internal combustion engines using a spatial light modulator

    International Nuclear Information System (INIS)

    Lyon, Elliott; Kuang, Zheng; Dearden, Geoff; Cheng, Hua; Page, Vincent; Shenton, Tom

    2014-01-01

    This paper reports on a technique demonstrating for the first time successful multi-point laser-induced spark generation, which is variable in three dimensions and derived from a single laser beam. Previous work on laser ignition of internal combustion engines found that simultaneously igniting in more than one location resulted in more stable and faster combustion – a key potential advantage over conventional spark ignition. However, previous approaches could only generate secondary foci at fixed locations. The work reported here is an experimental technique for multi-point laser ignition, in which several sparks with arbitrary spatial location in three dimensions are created by variable diffraction of a pulsed single laser beam source and transmission through an optical plug. The diffractive multi-beam arrays and patterns are generated using a spatial light modulator on which computer generated holograms are displayed. A gratings and lenses algorithm is used to accurately modulate the phase of the input laser beam and create multi-beam output. The underpinning theory, experimental arrangement and results obtained are presented and discussed. (paper)

  18. Modulating the line shape of magnetoconductance by varying the charge injection in polymer light-emitting diodes

    Directory of Open Access Journals (Sweden)

    Nidya Chitraningrum

    2018-02-01

    Full Text Available We fabricate the phenyl-substituted poly(p-phenylene vinylene copolymer (super yellow, SY-PPV-based polymer light-emitting diodes (PLEDs with different device architectures to modulate the injection of opposite charge carriers and investigate the corresponding magnetoconductance (MC responses. At the first glance, we find that all PLEDs exhibit the positive MC responses. By applying the mathematical analysis to fit the curves with two empirical equations of a non-Lorentzian and a Lorentzian function, we are able to extract the hidden negative MC component from the positive MC curve. We attribute the growth of the negative MC component to the reduced interaction of the triplet excitons with charges to generate the free charge carriers as modulated by the applied magnetic field, known as the triplet exciton-charge reaction, by analyzing MC responses for PLEDs of the charge-unbalanced and hole-blocking device configurations. The negative MC component causes the broadening of the line shape in MC curves.

  19. Early developmental responses to seedling environment modulate later plasticity to light spectral quality.

    Directory of Open Access Journals (Sweden)

    Eric J B von Wettberg

    Full Text Available Correlations between developmentally plastic traits may constrain the joint evolution of traits. In plants, both seedling de-etiolation and shade avoidance elongation responses to crowding and foliage shade are mediated by partially overlapping developmental pathways, suggesting the possibility of pleiotropic constraints. To test for such constraints, we exposed inbred lines of Impatiens capensis to factorial combinations of leaf litter (which affects de-etiolation and simulated foliage shade (which affects phytochrome-mediated shade avoidance. Increased elongation of hypocotyls caused by leaf litter phenotypically enhanced subsequent elongation of the first internode in response to low red:far red (R:FR. Trait expression was correlated across litter and shade conditions, suggesting that phenotypic effects of early plasticity on later plasticity may affect variation in elongation traits available to selection in different light environments.

  20. Virulence Effects and Signaling Partners Modulated by Brucella melitensis Light-sensing Histidine Kinase

    Science.gov (United States)

    Gourley, Christopher R.

    The facultative intracellular pathogen Brucella melitensis utilizes diverse virulence factors. A Brucella light sensing histidine kinase can influence in vitro virulence of the bacteria during intracellular infection. First, we demonstrated that the B. melitensis light sensing kinase (BM-LOV-HK) affects virulence in an IRF-1-/- mouse model of infection. Infection with a Δ BM-LOV-HK strain resulted in less bacterial colonization of IRF-1-/- spleens and extended survivorship compared to mice infected with wild type B. melitensis 16M. Second, using PCR arrays, we observed less expression of innate and adaptive immune system activation markers in ΔBM-LOV-HK infected mouse spleens than wild type B. melitensis 16M infected mouse spleens 6 days after infection. Third, we demonstrated by microarray analysis of B. melitensis that deletion of BM-LOV-HK alters bacterial gene expression. Downregulation of genes involved in control of the general stress response system included the alternative sigma factor RpoE1 and its anti-anti sigma factor PhyR. Conversely, genes involved in flagella production, quorum sensing, and the type IV secretion system (VirB operon) were upregulated in the Δ BM-LOV-HK strain compared to the wild type B. melitensis 16M. Analysis of genes differentially regulated in Δ BM-LOV-HK versus the wild type strain indicated an overlap of 110 genes with data from previous quorum sensing regulator studies of Δ vjbR and/ΔblxR(babR) strains. Also, several predicted RpoE1 binding sites located upstream of genes were differentially regulated in the ΔBM-LOV-HK strain. Our results suggest BM-LOV-HK is important for in vivo Brucella virulence, and reveals that BM-LOV-HK directly or indirect regulates members of the Brucella quorum sensing, type IV secretion, and general stress systems.

  1. Broadband unidirectional ultrasound propagation

    Science.gov (United States)

    Sinha, Dipen N.; Pantea, Cristian

    2017-12-12

    A passive, linear arrangement of a sonic crystal-based apparatus and method including a 1D sonic crystal, a nonlinear medium, and an acoustic low-pass filter, for permitting unidirectional broadband ultrasound propagation as a collimated beam for underwater, air or other fluid communication, are described. The signal to be transmitted is first used to modulate a high-frequency ultrasonic carrier wave which is directed into the sonic crystal side of the apparatus. The apparatus processes the modulated signal, whereby the original low-frequency signal exits the apparatus as a collimated beam on the side of the apparatus opposite the sonic crystal. The sonic crystal provides a bandpass acoustic filter through which the modulated high-frequency ultrasonic signal passes, and the nonlinear medium demodulates the modulated signal and recovers the low-frequency sound beam. The low-pass filter removes remaining high-frequency components, and contributes to the unidirectional property of the apparatus.

  2. Analysis of the unmodulated diffraction beam of the phase-only liquid crystal spatial light modulator and a method for reducing its influence

    International Nuclear Information System (INIS)

    Qi, Yue; Li, Dayu; Hu, Lifa; Xuan, Li; Xia, Mingliang

    2012-01-01

    As a wavefront corrector, the phase-only liquid crystal spatial light modulator has been widely using in adaptive optics systems. However, the unmodulated diffracted beam of the modulator will affect the light spot centroid detection accuracy of a Shack–Hartmann wavefront sensor and decrease the image quality after correction. In this paper, we have diminished the effect by introducing a modified weight algorithm in our closed-loop adaptive optics system. The Strehl ratio of the image is higher than 0.8 after correction, even when the wavefront aberration is larger than 3 μm. The correction precision and image quality are both improved significantly. (paper)

  3. Autostereoscopic three-dimensional display by combining a single spatial light modulator and a zero-order nulled grating

    Science.gov (United States)

    Su, Yanfeng; Cai, Zhijian; Liu, Quan; Lu, Yifan; Guo, Peiliang; Shi, Lingyan; Wu, Jianhong

    2018-04-01

    In this paper, an autostereoscopic three-dimensional (3D) display system based on synthetic hologram reconstruction is proposed and implemented. The system uses a single phase-only spatial light modulator to load the synthetic hologram of the left and right stereo images, and the parallax angle between two reconstructed stereo images is enlarged by a grating to meet the split angle requirement of normal stereoscopic vision. To realize the crosstalk-free autostereoscopic 3D display with high light utilization efficiency, the groove parameters of the grating are specifically designed by the rigorous coupled-wave theory for suppressing the zero-order diffraction, and then the zero-order nulled grating is fabricated by the holographic lithography and the ion beam etching. Furthermore, the diffraction efficiency of the fabricated grating is measured under the illumination of a laser beam with a wavelength of 532 nm. Finally, the experimental verification system for the proposed autostereoscopic 3D display is presented. The experimental results prove that the proposed system is able to generate stereoscopic 3D images with good performances.

  4. Short - Term Exposure To Visible And Ultraviolet Light Modulates Dacarbazine Toxicity To Human Blood Cells In Vitro

    International Nuclear Information System (INIS)

    Kopjar, N.; Zunec, S.; Lucic Vrdoljak, A.; Zeljezic, D.; Mladinic, M.

    2015-01-01

    Dacarbazine (DTIC), i.e. 5-(3,3-dimethyltriazeno)imidazol-4-carboxamide, is an alkylating cytostatic used in the treatment of various types of human cancer. It is prone to photodegradation, the products of which cause adverse effects in treated patients. In the present study, we evaluated the relationships between photo genotoxicity, cytotoxicity, lipid peroxidation and AChE activity in in vitro DTIC - treated human blood after illumination with visible and ultraviolet light for 30 and 60 minutes. AChE activity was measured in erythrocytes. The extent of lipid peroxidation was measured in plasma. Cell death and morphological changes in the nuclei were studied in isolated peripheral blood lymphocytes using the fluorescent dye exclusion method. Primary DNA damage in lymphocytes was studied by alkaline comet assay immediately after treatment and 60 minutes later. The obtained results suggest that short-term exposure to UV and visible light modulated DTIC toxicity. Most of the effects were dose-dependent. We assume that photodegradation products, together with the parent compound, were responsible for increased LPO in plasma, along with cytotoxicity and infliction of primary DNA damage in lymphocytes. Erythrocyte AChE activity, on the other hand, was strongly impaired by the parent drug. Our findings suggest the need for a simultaneous evaluation of cyto-/genotoxicity and biochemical markers, as such an approach would provide much better insight into the mechanisms underlying drug toxicity in general. (author).

  5. Pulse oximeter using a gain-modulated avalanche photodiode operated in a pseudo lock-in light detection mode

    Science.gov (United States)

    Miyata, Tsuyoshi; Iwata, Tetsuo; Araki, Tsutomu

    2006-01-01

    We propose a reflection-type pulse oximeter, which employs two pairs of a light-emitting diode (LED) and a gated avalanche photodiode (APD). One LED is a red one with an emission wavelength λ = 635 nm and the other is a near-infrared one with that λ = 945 nm, which are both driven with a pulse mode at a frequency f (=10 kHz). Superposition of a transistor-transistor-logic (TTL) gate pulse on a direct-current (dc) bias, which is set so as not exceeding the breakdown voltage of each APD, makes the APD work in a gain-enhanced operation mode. Each APD is gated at a frequency 2f (=20 kHz) and its output signal is fed into a laboratory-made lock-in amplifier that works in synchronous with the pulse modulation signal of each LED at a frequency f (=10 kHz). A combination of the gated APD and the lock-in like signal detection scheme is useful for the reflection-type pulse oximeter thanks to the capability of detecting a weak signal against a large background (BG) light.

  6. Retinoic acid modulation of ultraviolet light-induced epidermal ornithine decarboxylase activity

    International Nuclear Information System (INIS)

    Lowe, N.J.; Breeding, J.

    1982-01-01

    Irradiation of skin with ultraviolet light of sunburn range (UVB) leads to a large and rapid induction of the polyamine biosynthetic enzyme ornithine decarboxylase in the epidermis. Induction of epidermal ornithine decarboxylase also occurs following application of the tumor promoting agent 12-0-tetradecanoylphorbol-13 acetate and topical retinoic acid is able to block both this ornithine decarboxylase induction and skin tumor promotion. In the studies described below, topical application of retinoic acid to hairless mouse skin leads to a significant inhibition of UVB-induced epidermal ornithine decarboxylase activity. The degree of this inhibition was dependent on the dose, timing, and frequency of the application of retinoic acid. To show significant inhibition of UVB-induced ornithine decarboxylase the retinoic acid had to be applied within 5 hr of UVB irradiation. If retinoic acid treatment was delayed beyond 7 hr following UVB, then no inhibition of UVB-induced ornithine decarboxylase was observed. The quantities of retinoic acid used (1.7 nmol and 3.4 nmol) have been shown effective at inhibiting 12-0-tetradecanoyl phorbol-13 acetate induced ornithine decarboxylase. The results show that these concentrations of topical retinoic acid applied either before or immediately following UVB irradiation reduces the UVB induction of epidermal ornithine decarboxylase. The effect of retinoic acid in these regimens on UVB-induced skin carcinogenesis is currently under study

  7. Fetal Ultrasound

    Science.gov (United States)

    ... isn't recommended simply to determine a baby's sex. Similarly, fetal ultrasound isn't recommended solely for the purpose of producing keepsake videos or pictures. If your health care provider doesn' ...

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  9. Prostate Ultrasound

    Medline Plus

    Full Text Available ... and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... nodule felt by a physician during a routine physical exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time ...

  11. Prostate Ultrasound

    Medline Plus

    Full Text Available ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ... well on x-ray images. Ultrasound causes no health problems and may be repeated as often as ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  13. Prostate Ultrasound

    Medline Plus

    Full Text Available ... probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ... the transducer (the device placed on the patient's skin to send and receive the returning sound waves), ...

  14. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ... the transducer (the device placed on the patient's skin to send and receive the returning sound waves), ...

  15. Prostate Ultrasound

    Medline Plus

    Full Text Available ... no ionizing radiation. Ultrasound scanning may be able to give a clearer picture of soft tissues that do ... understanding of the possible charges you will incur. Web page review process: This Web page is reviewed ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... use different transducers (with different capabilities) during a single exam. The transducer sends out high-frequency sound ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  17. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

  19. Prostate Ultrasound

    Medline Plus

    Full Text Available ... sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of ...

  20. Prostate Ultrasound

    Medline Plus

    Full Text Available ... is located directly in front of the rectum, so the ultrasound exam is performed transrectally in order ... A follow-up examination may also be necessary so that any change in a known abnormality can ...

  1. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the rectal wall is relatively insensitive to the pain in the region of the prostate. A biopsy ... needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on ...

  2. Prostate Ultrasound

    Medline Plus

    Full Text Available ... diagnose symptoms such as difficulty urinating or an elevated blood test result. It’s also used to investigate ... physical exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides ...

  3. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... The principles are similar to sonar used by boats and submarines. The ultrasound image is immediately visible ... principles involved in the sonar used by bats, ships and fishermen. When a sound wave strikes an ...

  4. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... areas of the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ... make secure contact with the body and eliminate air pockets between the transducer and the skin that ...

  5. Prostate Ultrasound

    Medline Plus

    Full Text Available ... a follow-up exam is done because a potential abnormality needs further evaluation with additional views or ... of soft tissues that do not show up well on x-ray images. Ultrasound causes no health ...

  6. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... a follow-up exam is done because a potential abnormality needs further evaluation with additional views or ... of soft tissues that do not show up well on x-ray images. Ultrasound is the preferred ...

  7. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... is smaller than the standard speculum used when performing a Pap test . A protective cover is placed ... of soft tissues that do not show up well on x-ray images. Ultrasound is the preferred ...

  8. Prostate Ultrasound

    Medline Plus

    Full Text Available ... scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on ... to do the scanning. The transducer is a small hand-held device that resembles a microphone, attached ...

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on ... the child prior to the exam. Bringing books, small toys, music or games can help to distract ...

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... less than 20 minutes. top of page What will I experience during and after the procedure? Ultrasound ... in the region of the prostate. A biopsy will add time to the procedure. Rarely, a small ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound images are reviewed. top of page What will I experience during and after the procedure? For ... in the region of the prostate. A biopsy will add time to the procedure. If a Doppler ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... arteries and veins in the abdomen, arms, legs, neck and/or brain (in infants and children) or ... diagnose symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams ...

  13. Prostate Ultrasound

    Medline Plus

    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the best way to see if treatment is working or if a finding is stable or changed ...

  14. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . ... move through vessels. The movement of blood cells causes a change in pitch of the reflected sound ...

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs such ... and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time imaging, making it a ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ... barium exams, CT scanning , and MRI are the methods of choice in such a setting. Large patients ...

  17. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... move through vessels. The movement of blood cells causes a change in pitch of the reflected sound ...

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  20. Ultrasound imaging

    International Nuclear Information System (INIS)

    Wells, P.N.T.

    1983-01-01

    Ultrasound is a form of energy which consists of mechanical vibrations the frequencies of which are so high that they are above the range of human hearing. The lower frequency limit of the ultrasonic spectrum may generally be taken to be about 20 kHz. Most biomedical applications of ultrasound employ frequencies in the range 1-15 MHz. At these frequencies, the wavelength is in the range 1.5 - 0.1 mm in soft tissues, and narrow beams of ultrasound can be generated which propagate through such tissues without excessive attenuation. This chapter begins with brief reviews of the physics of diagnostic ultrasound pulse-echo imaging methods and Doppler imaging methods. The remainder of the chapter is a resume of the applications of ultrasonic imaging to physiological measurement

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  2. Prostate Ultrasound

    Medline Plus

    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  3. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... frequently used to evaluate the reproductive and urinary systems. Ultrasound is safe, noninvasive and does not use ... and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  4. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... be asked to drink water prior to the examination to fill your bladder. Leave jewelry at home ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ...

  5. Prostate Ultrasound

    Medline Plus

    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Prostate Cancer top of page ... to Ultrasound - Prostate Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  6. Prostate Ultrasound

    Medline Plus

    Full Text Available ... with measurements acquired as needed for any treatment planning. detect an abnormal growth within the prostate. help ... end of their bowel (rectum) removed during prior surgery are not good candidates for ultrasound of the ...

  7. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... tip of the transducer is smaller than the standard speculum used when performing a Pap test . A ... both sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects ...

  8. Prostate Ultrasound

    Medline Plus

    Full Text Available ... prostate gland and to help diagnose symptoms such as difficulty urinating or an elevated blood test result. ... image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no ...

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... in the abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs ... or uterine cancers A transvaginal ultrasound is usually performed to view ...

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... is enlarged, also known as benign prostatic hyperplasia (BPH) , with measurements acquired as needed for any treatment ... caption Related Articles and Media Benign Prostatic Hyperplasia (BPH) (Enlargement of the Prostate) Prostate Cancer Ultrasound- and ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the exam. Bringing books, small toys, music or games can help to distract the child and make ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries in planes that ... a special study usually done to provide detailed evaluation of the prostate gland, involves inserting a specialized ...

  13. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the examination process. To ensure a smooth experience, it often helps to explain the procedure to the ... on the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from ...

  14. Prostate Ultrasound

    Medline Plus

    Full Text Available ... difficulty urinating or an elevated blood test result. It’s also used to investigate a nodule found during ... difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide procedures such ...

  15. Prostate Ultrasound

    Medline Plus

    Full Text Available ... needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on ... and Resources RTAnswers.org Radiation Therapy for Prostate Cancer top of page This page was reviewed on ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects on ... and Resources RTAnswers.org Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page ...

  17. Prostate Ultrasound

    Medline Plus

    Full Text Available ... rectum. top of page What are some common uses of the procedure? A transrectal ultrasound of the ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ...

  18. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... legs, neck and/or brain (in infants and children) or within various body organs such as the ... tumors other disorders of the urinary bladder In children, pelvic ultrasound can help evaluate: pelvic masses pelvic ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... uterus). Sonohysterography allows for a more in-depth investigation of the uterine cavity . Three-dimensional (3-D) ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... is Pelvic Ultrasound Imaging? What are some common uses of the procedure? How should I prepare? What does the equipment look like? How does the procedure work? How is the procedure performed? What will I ...

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... quickly. The ultrasound exam room may have a television. Feel free to ask for your child's favorite ... display screen that looks like a computer or television monitor. The image is created based on the ...

  2. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Images related to Ultrasound - Prostate Sponsored by Please note RadiologyInfo.org is not a medical facility. Please ... is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of ...

  3. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Images related to Ultrasound - Pelvis Sponsored by Please note RadiologyInfo.org is not a medical facility. Please ... is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of ...

  4. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams also ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ...

  5. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... The ultrasound exam room may have a television. Feel free to ask for your child's favorite channel. ... performed over an area of tenderness, you may feel pressure or minor pain from the transducer. Once ...

  6. Prostate Ultrasound

    Medline Plus

    Full Text Available ... also known as benign prostatic hyperplasia (BPH) , with measurements acquired as needed for any treatment planning. detect ... areas of the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ...

  7. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ovarian cysts and uterine fibroids ovarian or uterine cancers A transvaginal ultrasound is usually performed to view ... detect: uterine anomalies uterine scars endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some ...

  8. Prostate Ultrasound

    Medline Plus

    Full Text Available ... rectum. top of page What are some common uses of the procedure? A transrectal ultrasound of the ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... kidneys. top of page What are some common uses of the procedure? In women, a pelvic ultrasound ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  10. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and ... standard diagnostic ultrasound , there are no known harmful effects on humans. top of page What are the ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... various body organs such as the liver or kidneys. top of page What are some common uses ... women, a pelvic ultrasound exam can help identify: kidney stones bladder tumors other disorders of the urinary ...

  13. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls of the uterus). Sonohysterography allows for a ... and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  14. Prostate Ultrasound

    Medline Plus

    Full Text Available ... echoes from the tissues in the body. The principles are similar to sonar used by boats and ... work? Ultrasound imaging is based on the same principles involved in the sonar used by bats, ships ...

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... echoes from the tissues in the body. The principles are similar to sonar used by boats and ... work? Ultrasound imaging is based on the same principles involved in the sonar used by bats, ships ...

  16. Prostate Ultrasound

    Medline Plus

    Full Text Available ... is at high risk for cancer. In this case, a biopsy is performed and an ultrasound probe ... will share the results with you. In some cases, the radiologist may discuss results with you at ...

  17. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls of the uterus). Sonohysterography allows for a more ... needle insertion) is usually minimal because the rectal wall is relatively insensitive to the pain in the ...

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... uses sound waves to produce pictures of a man’s prostate gland and to help diagnose symptoms such ... also called transrectal ultrasound, provides images of a man's prostate gland and surrounding tissue. The exam typically ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... pain ambiguous genitalia and anomalies of pelvic organs early or delayed puberty in girls Pelvic ultrasound is ... sensitive to motion, and an active or crying child can prolong the examination process. To ensure a ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... consist of a console containing a computer and electronics, a video display screen and a transducer that ... the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound ...

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves ...

  2. Prostate Ultrasound

    Medline Plus

    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves ...

  3. Research interface on a programmable ultrasound scanner.

    Science.gov (United States)

    Shamdasani, Vijay; Bae, Unmin; Sikdar, Siddhartha; Yoo, Yang Mo; Karadayi, Kerem; Managuli, Ravi; Kim, Yongmin

    2008-07-01

    Commercial ultrasound machines in the past did not provide the ultrasound researchers access to raw ultrasound data. Lack of this ability has impeded evaluation and clinical testing of novel ultrasound algorithms and applications. Recently, we developed a flexible ultrasound back-end where all the processing for the conventional ultrasound modes, such as B, M, color flow and spectral Doppler, was performed in software. The back-end has been incorporated into a commercial ultrasound machine, the Hitachi HiVision 5500. The goal of this work is to develop an ultrasound research interface on the back-end for acquiring raw ultrasound data from the machine. The research interface has been designed as a software module on the ultrasound back-end. To increase the amount of raw ultrasound data that can be spooled in the limited memory available on the back-end, we have developed a method that can losslessly compress the ultrasound data in real time. The raw ultrasound data could be obtained in any conventional ultrasound mode, including duplex and triplex modes. Furthermore, use of the research interface does not decrease the frame rate or otherwise affect the clinical usability of the machine. The lossless compression of the ultrasound data in real time can increase the amount of data spooled by approximately 2.3 times, thus allowing more than 6s of raw ultrasound data to be acquired in all the modes. The interface has been used not only for early testing of new ideas with in vitro data from phantoms, but also for acquiring in vivo data for fine-tuning ultrasound applications and conducting clinical studies. We present several examples of how newer ultrasound applications, such as elastography, vibration imaging and 3D imaging, have benefited from this research interface. Since the research interface is entirely implemented in software, it can be deployed on existing HiVision 5500 ultrasound machines and may be easily upgraded in the future. The developed research

  4. Cranial Ultrasound/Head Ultrasound

    Science.gov (United States)

    ... used to screen for brain conditions associated with prematurity, such as bleeding or brain tissue damage as ... or crying child will slow the examination process. Large patients are more difficult to image by ultrasound, ...

  5. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... guide biopsy of breast cancer ( see the Ultrasound-Guided Breast Biopsy page . diagnose a variety of heart ... Articles and Media Angioplasty and Vascular Stenting Ultrasound-Guided Breast Biopsy Obstetric Ultrasound Ultrasound - Prostate Biopsies - Overview ...

  6. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... of an ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a special ultrasound technique that ... kidneys. There are three types of Doppler ultrasound: Color Doppler uses a computer to convert Doppler measurements ...

  7. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce pictures of the inside of ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  8. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ... ultrasound study may be part of an ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is ...

  9. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... What are the limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and ... be heard with every heartbeat. top of page What are some common uses of the procedure? Ultrasound ...

  10. Ce3+-Doping to Modulate Photoluminescence Kinetics for Efficient CsPbBr3 Nanocrystals Based Light-Emitting Diodes.

    Science.gov (United States)

    Yao, Ji-Song; Ge, Jing; Han, Bo-Ning; Wang, Kun-Hua; Yao, Hong-Bin; Yu, Hao-Lei; Li, Jian-Hai; Zhu, Bai-Sheng; Song, Ji-Zhong; Chen, Chen; Zhang, Qun; Zeng, Hai-Bo; Luo, Yi; Yu, Shu-Hong

    2018-03-14

    Inorganic perovskite CsPbBr 3 nanocrystals (NCs) are emerging, highly attractive light emitters with high color purity and good thermal stability for light-emitting diodes (LEDs). Their high photo/electroluminescence efficiencies are very important for fabricating efficient LEDs. Here, we propose a novel strategy to enhance the photo/electroluminescence efficiency of CsPbBr 3 NCs through doping of heterovalent Ce 3+ ions via a facile hot-injection method. The Ce 3+ cation was chosen as the dopant for CsPbBr 3 NCs by virtue of its similar ion radius and formation of higher energy level of conduction band with bromine in comparison with the Pb 2+ cation to maintain the integrity of perovskite structure without introducing additional trap states. It was found that by increasing the doping amount of Ce 3+ in CsPbBr 3 NCs to 2.88% (atomic percentage of Ce compared to Pb) the photoluminescence quantum yield (PLQY) of CsPbBr 3 NCs reached up to 89%, a factor of 2 increase in comparison with the native, undoped ones. The ultrafast transient absorption and time-resolved photoluminescence (PL) spectroscopy revealed that Ce 3+ -doping can significantly modulate the PL kinetics to enhance the PL efficiency of doped CsPbBr 3 NCs. As a result, the LED device fabricated by adopting Ce 3+ -doped CsPbBr 3 NCs as the emitting layers exhibited a pronounced improvement of electroluminescence with external quantum efficiency (EQE) from 1.6 to 4.4% via Ce 3+ -doping.

  11. Ultrasound cleaning of microfilters

    DEFF Research Database (Denmark)

    Hald, Jens; Bjørnø, Irina; Jensen, Leif Bjørnø

    1999-01-01

    The aim of the present work is to develop, design, and manufacture a high-power ultrasound transducer module to be used for preventing the blocking of plastic-based microfilters by organic materials, and possibly to prolong the lifetime of the filters in industry using the cavitation on the surface...... suitable for cleaning of microfilters without damaging the filter structure. The filter surface was studied using an optical microscope before and after the experiment. When high-power ultrasound (max. 75 W/cm2) was applied to the surface of some microfilters, no visible damage was found, while others...... of the filter. A numerical, FE- and BE-based model for calculation of the response of ultrasonic transducers of various geometries formed the basis for the design of such transducers. During laboratory experiments frequency and output power have been varied in order to find the optimal transducer design...

  12. Pulse Compression Techniques for Laser Generated Ultrasound

    Science.gov (United States)

    Anastasi, R. F.; Madaras, E. I.

    1999-01-01

    Laser generated ultrasound for nondestructive evaluation has an optical power density limit due to rapid high heating that causes material damage. This damage threshold limits the generated ultrasound amplitude, which impacts nondestructive evaluation inspection capability. To increase ultrasound signal levels and improve the ultrasound signal-to-noise ratio without exceeding laser power limitations, it is possible to use pulse compression techniques. The approach illustrated here uses a 150mW laser-diode modulated with a pseudo-random sequence and signal correlation. Results demonstrate the successful generation of ultrasonic bulk waves in aluminum and graphite-epoxy composite materials using a modulated low-power laser diode and illustrate ultrasound bandwidth control.

  13. Therapeutic ultrasound

    International Nuclear Information System (INIS)

    Crum, Lawrence A

    2004-01-01

    The use of ultrasound in medicine is now quite commonplace, especially with the recent introduction of small, portable and relatively inexpensive, hand-held diagnostic imaging devices. Moreover, ultrasound has expanded beyond the imaging realm, with methods and applications extending to novel therapeutic and surgical uses. These applications broadly include: tissue ablation, acoustocautery, lipoplasty, site-specific and ultrasound mediated drug activity, extracorporeal lithotripsy, and the enhancement of natural physiological functions such as wound healing and tissue regeneration. A particularly attractive aspect of this technology is that diagnostic and therapeutic systems can be combined to produce totally non-invasive, imageguided therapy. This general lecture will review a number of these exciting new applications of ultrasound and address some of the basic scientific questions and future challenges in developing these methods and technologies for general use in our society. We shall particularly emphasize the use of High Intensity Focused Ultrasound (HIFU) in the treatment of benign and malignant tumors as well as the introduction of acoustic hemostasis, especially in organs which are difficult to treat using conventional medical and surgical techniques. (amum lecture)

  14. Polycrystalline magnetic garnet films comprising weakly coupled crystallites for piezoelectrically-driven magneto-optic spatial light modulators

    Energy Technology Data Exchange (ETDEWEB)

    Mito, S.; Sakurai, H.; Takagi, H.; Inoue, M. [Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Baryshev, A. V. [Electronics-Inspired Interdisciplinary Research Institute Toyohashi, Aichi 441-8580 (Japan); Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation)

    2012-04-01

    We have investigated the magnetization process of the polycrystalline magnetic garnet films in order to determine the most suitable composition of garnet films for piezoelectrically-driven magneto-optic spatial light modulators (MOSLMs). For experiment, the bismuth-dysprosium-aluminum-substituted yttrium iron (Bi{sub 1.3}Dy{sub 0.7}Y{sub 1.0}Fe{sub 3.1}Al{sub 1.9}O{sub 12}) garnet films were deposited by an RF magnetron sputter and annealed at 700 deg. C in air. The annealing time was varied in a range of several minutes to control the grain size. The saturation magnetization, the remanent magnetization and the composition of the fabricated garnet films slightly changed versus the annealing time. Experiments showed that the coercivity and the grain size increased at longer annealing; the coercivity was larger for films with bigger grains. This work shows that garnet films with smaller coercivity are most suitable for controlling the magnetization of garnet and, correspondingly, the magneto-optical rotation of MOSLM pixels driven by piezoelectrics.

  15. Improved performance of quantum dot light emitting diode by modulating electron injection with yttrium-doped ZnO nanoparticles

    Science.gov (United States)

    Li, Jingling; Guo, Qiling; Jin, Hu; Wang, Kelai; Xu, Dehua; Xu, Yongjun; Xu, Gang; Xu, Xueqing

    2017-10-01

    In a typical light emitting diode (QD-LED), with ZnO nanoparticles (NPs) serving as the electron transport layer (ETL) material, excessive electron injection driven by the matching conduction band maximum (CBM) between the QD and this oxide layer usually causes charge imbalance and degrades the device performance. To address this issue, the electronic structure of ZnO NPs is modified by the yttrium (Y) doping method. We demonstrate that the CBM of ZnO NPs has a strong dependence on the Y-doping concentration, which can be tuned from 3.55 to 2.77 eV as the Y doping content increases from 0% to 9.6%. This CBM variation generates an enlarged barrier between the cathode and this ZnO ETL benefits from the modulation of electron injection. By optimizing electron injection with the use of a low Y-doped (2%) ZnO to achieve charge balance in the QD-LED, device performance is significantly improved with maximum luminance, peak current efficiency, and maximal external quantum efficiency increase from 4918 cd/m2, 11.3 cd/A, and 4.5% to 11,171 cd/m2, 18.3 cd/A, and 7.3%, respectively. This facile strategy based on the ETL modification enriches the methodology of promoting QD-LED performance.

  16. Reaction of photochemical resists used in screen printing under the influence of digitally modulated ultra violet light

    Science.gov (United States)

    Gmuender, T.

    2017-02-01

    Different chemical photo-reactive emulsions are used in screen printing for stencil production. Depending on the bandwidth, optical power and depth of field from the optical system, the reaction / exposure speed has a diverse value. In this paper, the emulsions get categorized and validated in a first step. After that a mathematical model gets developed and adapted due to heuristic experience to estimate the exposure speed under the influence of digitally modulated ultra violet (UV) light. The main intention is to use the technical specifications (intended wavelength, exposure time, distance to the stencil, electrical power, stencil configuration) in the emulsion data sheet primary written down with an uncertainty factor for the end user operating with large projector arc lamps and photo films. These five parameters are the inputs for a mathematical formula which gives as an output the exposure speed for the Computer to Screen (CTS) machine calculated for each emulsion / stencil setup. The importance of this work relies in the possibility to rate with just a few boundaries the performance and capacity of an exposure system used in screen printing instead of processing a long test series for each emulsion / stencil configuration.

  17. Local electrophoresis deposition assisted by laser trapping coupled with a spatial light modulator for three-dimensional microfabrication

    Science.gov (United States)

    Matsuura, Toshiki; Takai, Takanari; Iwata, Futoshi

    2017-10-01

    We describe a novel three-dimensional fabrication technique using local electrophoresis deposition assisted by laser trapping coupled with a spatial light modulator (SLM). In a solution containing nanometer-scale colloidal Au particles, multiple laser spots formed on a conductive substrate by the SLM gathered the nanoparticles together, and then the nanoparticles were electrophoretically deposited onto the substrate by an applied electrical field. However, undesirable sub-spots often appeared due to optical interference from the multiple laser spots, which deteriorated the accuracy of the deposition. To avoid the appearance of undesirable sub-spots, we proposed a method using quasi-multiple spots, which we realized by switching the position of a single spot briefly using the SLM. The method allowed us to deposit multiple dots on the substrate without undesirable sub-dot deposition. By moving the substrate downward during deposition, multiple micro-pillar structures could be fabricated. As a fabrication property, the dependence of the pillar diameter on laser intensity was investigated by changing the number of laser spots. The smallest diameter of the four pillars fabricated in this study was 920 nm at the laser intensity of 2.5 mW. To demonstrate the effectiveness of the method, multiple spiral structures were fabricated. Quadruple spirals of 46 µm in height were successfully fabricated with a growth rate of 0.21 µm/s using 2200 frames of the CGH patterns displayed in the SLM at a frame rate of 10 fps.

  18. Aluminum nitride coatings using response surface methodology to optimize the thermal dissipated performance of light-emitting diode modules

    Science.gov (United States)

    Jean, Ming-Der; Lei, Peng-Da; Kong, Ling-Hua; Liu, Cheng-Wu

    2018-05-01

    This study optimizes the thermal dissipation ability of aluminum nitride (AlN) ceramics to increase the thermal performance of light-emitting diode (LED) modulus. AlN powders are deposited on heat sink as a heat interface material, using an electrostatic spraying process. The junction temperature of the heat sink is developed by response surface methodology based on Taguchi methods. In addition, the structure and properties of the AlN coating are examined using X-ray photoelectron spectroscopy (XPS). In the XPS analysis, the AlN sub-peaks are observed at 72.79 eV for Al2p and 398.88 eV for N1s, and an N1s sub-peak is assigned to N-O at 398.60eV and Al-N bonding at 395.95eV, which allows good thermal properties. The results have shown that the use of AlN ceramic material on a heat sink can enhance the thermal performance of LED modules. In addition, the percentage error between the predicted and experimental results compared the quadric model with between the linear and he interaction models was found to be within 7.89%, indicating that it was a good predictor. Accordingly, RSM can effectively enhance the thermal performance of an LED, and the beneficial heat dissipation effects for AlN are improved by electrostatic spraying.

  19. Generation of sinusoidal fringes with a holographic phase grating and a phase-only spatial light modulator

    International Nuclear Information System (INIS)

    Berberova, Natalia; Stoykova, Elena; Sainov, Ventseslav

    2012-01-01

    A variety of pattern projection methods for the three-dimensional capture of objects is based on the generation of purely sinusoidal fringes. This is not an easy task, especially when a portable non-interferometric system for outdoor usage is required. The use of phase gratings with coherent illumination as a possible solution has the advantage of providing good stability and a large measurement volume. In this work, we analyze the quality of fringes projected with two sinusoidal phase gratings. The first grating is recorded on a silver-halide holographic plate by means of a Michelson interferometer. The spatial resolution of the silver-halide material used is greater than 6000 lines per millimeter, and the recorded grating is practically analogous to a smooth variation of the phase profile. The second grating is formed as a sinusoidal phase variation on a liquid crystal-on-silicon phase-only reflective display with a resolution of 1920×1080 pixels, a pixel pitch of 8 μm and 256 phase levels. The frequency content of the fringes projected with both gratings is analyzed and compared on the basis of the calculated Fresnel diffraction pattern, taking into account that the sinusoidal phase distribution in the case of a spatial light modulator is both sampled and quantized. Experimental fringe patterns projected using both gratings are also provided.

  20. Magnetically modulated electroluminescence from hybrid organic/inorganic light-emitting diodes based on electron donor-acceptor exciplex blends

    Science.gov (United States)

    Pang, Zhiyong; Baniya, Sangita; Zhang, Chuang; Sun, Dali; Vardeny, Z. Valy

    2016-03-01

    We report room temperature magnetically modulated electroluminescence from a hybrid organic/inorganic light-emitting diode (h-OLED), in which an inorganic magnetic tunnel junction (MTJ) with large room temperature magnetoresistance is coupled to an N,N,N ',N '-Tetrakis(4-methoxyphenyl)benzidine (MeO-TPD): tris-[3-(3-pyridyl)mesityl]borane (3TPYMB) [D-A] based OLED that shows thermally activated delayed luminescence. The exciplex-based OLED provides two spin-mixing channels: upper energy channel of polaron pairs and lower energy channel of exciplexes. In operation, the large resistance mismatch between the MTJ and OLED components is suppressed due to the non-linear I-V characteristic of the OLED. This leads to enhanced giant magneto-electroluminescence (MEL) at room temperature. We measured MEL of ~ 75% at ambient conditions. Supported by SAMSUNG Global Research Outreach (GRO) program, and also by the NSF-Material Science & Engineering Center (MRSEC) program at the University of Utah (DMR-1121252).

  1. Terahertz Coherent Synchrotron Radiation from Femtosecond Laser Modulation of the Electron Beam at the Advanced Light Source

    International Nuclear Information System (INIS)

    Byrd, John M.; Hao, Zhao; Martin, Michael C.; Robin, David S.; Sannibale, Fernando; Schoenlein, Robert W.; Zholents, Alexander A.; Zolotorev, Max S.

    2005-01-01

    At the Advanced Light Source (ALS), the ''femtoslicing'' beamline is in operation since 1999 for the production of x-ray synchrotron radiation pulses with femtosecond duration. The mechanism used for generating the short x-ray pulses induces at the same time temporary structures in the electron bunch longitudinal distribution with very short characteristic length. Such structures emit intense coherent synchrotron radiation (CSR) in the terahertz frequency range. These CSR pulses were first observed at the ALS, and the measurement of their intensity is now routinely used as a diagnostics for the tune-up of the femtoslicing x-ray experiments. At the same time, these CSR pulses synchronous with the modulating laser, represent a potential source of terahertz radiation with very interesting features. Several measurements have been performed for their characterization and in this paper we present an updated description of the experimental results and of their interpretation. In particular, we include more data on the interesting interaction, previously observed at the ALS, between the slicing and the microbunching instability (MBI), where under particular circumstances, the slicing seems to trigger the onset of the instability

  2. Light-reflection random-target method for measurement of the modulation transfer function of a digital video-camera

    Science.gov (United States)

    Pospisil, J.; Jakubik, P.; Machala, L.

    2005-11-01

    This article reports the suggestion, realization and verification of the newly developed measuring means of the noiseless and locally shift-invariant modulation transfer function (MTF) of a digital video camera in a usual incoherent visible region of optical intensity, especially of its combined imaging, detection, sampling and digitizing steps which are influenced by the additive and spatially discrete photodetector, aliasing and quantization noises. Such means relates to the still camera automatic working regime and static two-dimensional spatially continuous light-reflection random target of white-noise property. The introduced theoretical reason for such a random-target method is also performed under exploitation of the proposed simulation model of the linear optical intensity response and possibility to express the resultant MTF by a normalized and smoothed rate of the ascertainable output and input power spectral densities. The random-target and resultant image-data were obtained and processed by means of a processing and evaluational PC with computation programs developed on the basis of MATLAB 6.5E The present examples of results and other obtained results of the performed measurements demonstrate the sufficient repeatability and acceptability of the described method for comparative evaluations of the performance of digital video cameras under various conditions.

  3. Adaptive optics scanning laser ophthalmoscope using liquid crystal on silicon spatial light modulator: Performance study with involuntary eye movement

    Science.gov (United States)

    Huang, Hongxin; Toyoda, Haruyoshi; Inoue, Takashi

    2017-09-01

    The performance of an adaptive optics scanning laser ophthalmoscope (AO-SLO) using a liquid crystal on silicon spatial light modulator and Shack-Hartmann wavefront sensor was investigated. The system achieved high-resolution and high-contrast images of human retinas by dynamic compensation for the aberrations in the eyes. Retinal structures such as photoreceptor cells, blood vessels, and nerve fiber bundles, as well as blood flow, could be observed in vivo. We also investigated involuntary eye movements and ascertained microsaccades and drifts using both the retinal images and the aberrations recorded simultaneously. Furthermore, we measured the interframe displacement of retinal images and found that during eye drift, the displacement has a linear relationship with the residual low-order aberration. The estimated duration and cumulative displacement of the drift were within the ranges estimated by a video tracking technique. The AO-SLO would not only be used for the early detection of eye diseases, but would also offer a new approach for involuntary eye movement research.

  4. Study Modules for Calculus-Based General Physics. [Includes Modules 31-34: Inductance; Wave Properties of Light; Interference; and Introduction to Quantum Physics].

    Science.gov (United States)

    Fuller, Robert G., Ed.; And Others

    This is Part of a series of 41 Calculus Based Physics (CBP) modules totaling about 1,000 Pages. The modules include study guides, practice tests, and mastery tests for a full-year individualized courses in calculus-based physics based on the Personalized System of Instruction (PSI). The units are not intended to be used without outside materials;…

  5. In-line monitoring technique with visible light from 1.3 microm-band SHG module for optical access systems.

    Science.gov (United States)

    Kubo, Takahiro; Taniguchi, Tomohiro; Tadanaga, Osamu; Sakurai, Naoya; Kimura, Hideaki; Hadama, Hisaya; Asobe, Masaki

    2010-02-01

    We propose an in-line monitoring technique that uses 650 nm visible light for performing maintenance work on Fiber-to-the-home (FTTH) network quickly without the need for measuring skills or external devices. This technique is characterized by visible light (650 nm) generated by an SHG module from the 1.3 microm-band line signal. We fabricate a 1.3 microm-band quasi phase matched LiNbO(3) (QPM-LN) module, and the measure the 650 nm second harmonic (SH) power to test the proposed short-pulse modulation method. The results confirm the feasibility of the short-pulse modulation method with different peak factors (PFs) (1.0-7.3). We also examine the effect of short-pulse modulation on system performance at the optical receiver by measuring the bit error rate (BER) of received data (1.25 Gb/s). The BER is basically unaffected by the PF (1.0-5.5). This means that the proposed technique has little influence on data reception as regards PF (1.0-5.5).

  6. Dual-Band Modulation of Visible and Near-Infrared Light Transmittance in an All-Solution-Processed Hybrid Micro-Nano Composite Film.

    Science.gov (United States)

    Liang, Xiao; Chen, Mei; Guo, Shumeng; Zhang, Lanying; Li, Fasheng; Yang, Huai

    2017-11-22

    Smart windows with controllable visible and near-infrared light transmittance can significantly improve the building's energy efficiency and inhabitant comfort. However, most of the current smart window technology cannot achieve the target of ideal solar control. Herein, we present a novel all-solution-processed hybrid micronano composite smart material that have four optical states to separately modulate the visible and NIR light transmittance through voltage and temperature, respectively. This dual-band optical modulation was achieved by constructing a phase-separated polymer framework, which contains the microsized liquid crystals domains with a negative dielectric constant and tungsten-doped vanadium dioxide (W-VO 2 ) nanocrystals (NCs). The film with 2.5 wt % W-VO 2 NCs exhibits transparency at normal condition, and the passage of visible light can be reversibly and actively regulated between 60.8% and 1.3% by external applied voltage. Also, the transmittance of NIR light can be reversibly and passively modulated between 59.4% and 41.2% by temperature. Besides, the film also features easy all-solution processability, fast electro-optical (E-O) response time, high mechanical strength, and long-term stability. The as-prepared film provides new opportunities for next-generation smart window technology, and the proposed strategy is conductive to engineering novel hybrid inorganic-organic functional matters.

  7. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the prostate. help diagnose the cause of a man's infertility. A transrectal ultrasound of the prostate gland is typically used to help diagnose symptoms such as: a nodule felt by a physician during a routine physical exam or prostate cancer screening exam. an elevated ...

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... and Resources RTAnswers.org Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page This page was reviewed on ... with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. ... Images related to Ultrasound - Pelvis Sponsored by Please ...

  9. Prostate Ultrasound

    Medline Plus

    Full Text Available ... body tissue through which the sound travels. A small amount of gel is put on the skin to allow the sound waves to travel from the transducer to the examined area within the body and then back again. Ultrasound ...

  10. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... body tissue through which the sound travels. A small amount of gel is put on the skin to allow the sound waves to travel from the transducer to the examined area within the body and then back again. Ultrasound ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during pregnancy. See the ... can help to identify and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and creates graphs ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally ... known harmful effects on humans. top of page What are the ...

  13. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  14. Prostate Ultrasound

    Medline Plus

    Full Text Available ... symptoms such as difficulty urinating or an elevated blood test result. It’s also used to investigate a nodule ... exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time ...

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... in which needles are used to extract a sample of cells from organs for laboratory testing. Doppler ultrasound images can help the physician to see and evaluate: blockages to blood flow (such as clots) narrowing of vessels tumors ...

  16. Prostate Ultrasound

    Medline Plus

    Full Text Available ... exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide procedures such as needle biopsies , in which a needle is used to sample cells (tissue) from an abnormal area in the ...

  17. Prostate Ultrasound

    Medline Plus

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may ...

  18. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound is the preferred imaging modality for ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from the area within the patient that is being examined to the transducer (the device placed on the patient's skin to send and ...

  20. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from the area within the patient that is being examined to the transducer (the device placed on the patient's skin to send and ...

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... by a computer, which in turn creates a real-time picture on the monitor. One or more frames ...

  2. Obstetrical ultrasound

    International Nuclear Information System (INIS)

    Bundy, A.L.

    1988-01-01

    The use of diagnostic ultrasound in obstetrics may provide fuel for legal action. While most legal implications of this relatively new imaging modality are purely speculative, some have already given rise to legal action. Several situations will likely provide a basis for the courts to find against the physician. The failure to perform a sonogram when clinically indicated will most likely be the strongest plaintiff argument. Other major concerns include the use and availability of state-of-the-art equipment, as well as interpretation of the scans by a trained physician. Obstetrical ultrasound is usually performed by a radiologist or obstetrician. However, many physicians performing these examinations have had little or no formal training in the field. While this is now being remedied by the respective board examines who require a certain amount of training, it may not be enough. When ultrasound-related cases reach the courts, the involved physicians will most likely be regarded as experts in the field and, therefore, will be held to a very high standard of care. This would be difficult to achieve without formal training. At the present time, the American Board of Radiology requires more training time in ultrasound than the American Board of Obstetrics and Gynecology

  3. Manipulating femtosecond laser interactions in bulk glass and thin-film with spatial light modulation (Conference Presentation)

    Science.gov (United States)

    Alimohammadian, Ehsan; Ho, Stephen; Ertorer, Erden; Gherghe, Sebastian; Li, Jianzhao; Herman, Peter R.

    2017-03-01

    Spatial Light Modulators (SLM) are emerging as a power tool for laser beam shaping whereby digitally addressed phase shifts can impose computer-generated hologram patterns on incoming laser light. SLM provide several additional advantages with ultrashort-pulsed lasers in controlling the shape of both surface and internal interactions with materials. Inside transparent materials, nonlinear optical effects can confine strong absorption only to the focal volume, extend dissipation over long filament tracks, or reach below diffraction-limited spot sizes. Hence, SLM beam shaping has been widely adopted for laser material processing applications that include parallel structuring, filamentation, fiber Bragg grating formation and optical aberration correction. This paper reports on a range of SLM applications we have studied in femtosecond processing of transparent glasses and thin films. Laser phase-fronts were tailored by the SLM to compensate for spherical surface aberration, and to further address the nonlinear interactions that interplay between Kerr-lens self-focusing and plasma defocusing effects over shallow and deep focusing inside the glass. Limits of strong and weak focusing were examined around the respective formation of low-loss optical waveguides and long uniform filament tracks. Further, we have employed the SLM for beam patterning inside thin film, exploring the limits of phase noise, resolution and fringe contrast during interferometric intra-film structuring. Femtosecond laser pulses of 200 fs pulse duration and 515 nm wavelength were shaped by a phase-only LCOS-SLM (Hamamatsu X10468-04). By imposing radial phase profiles, axicon, grating and beam splitting gratings, volume shape control of filament diameter, length, and uniformity as well as simultaneous formation of multiple filaments has been demonstrated. Similarly, competing effects of spherical surface aberration, self-focusing, and plasma de-focusing were studied and delineated to enable formation

  4. Ultrasound imaging using coded signals

    DEFF Research Database (Denmark)

    Misaridis, Athanasios

    Modulated (or coded) excitation signals can potentially improve the quality and increase the frame rate in medical ultrasound scanners. The aim of this dissertation is to investigate systematically the applicability of modulated signals in medical ultrasound imaging and to suggest appropriate...... methods for coded imaging, with the goal of making better anatomic and flow images and three-dimensional images. On the first stage, it investigates techniques for doing high-resolution coded imaging with improved signal-to-noise ratio compared to conventional imaging. Subsequently it investigates how...... coded excitation can be used for increasing the frame rate. The work includes both simulated results using Field II, and experimental results based on measurements on phantoms as well as clinical images. Initially a mathematical foundation of signal modulation is given. Pulse compression based...

  5. Arrays of microLEDs and astrocytes: biological amplifiers to optogenetically modulate neuronal networks reducing light requirement.

    Directory of Open Access Journals (Sweden)

    Rolando Berlinguer-Palmini

    Full Text Available In the modern view of synaptic transmission, astrocytes are no longer confined to the role of merely supportive cells. Although they do not generate action potentials, they nonetheless exhibit electrical activity and can influence surrounding neurons through gliotransmitter release. In this work, we explored whether optogenetic activation of glial cells could act as an amplification mechanism to optical neural stimulation via gliotransmission to the neural network. We studied the modulation of gliotransmission by selective photo-activation of channelrhodopsin-2 (ChR2 and by means of a matrix of individually addressable super-bright microLEDs (μLEDs with an excitation peak at 470 nm. We combined Ca2+ imaging techniques and concurrent patch-clamp electrophysiology to obtain subsequent glia/neural activity. First, we tested the μLEDs efficacy in stimulating ChR2-transfected astrocyte. ChR2-induced astrocytic current did not desensitize overtime, and was linearly increased and prolonged by increasing μLED irradiance in terms of intensity and surface illumination. Subsequently, ChR2 astrocytic stimulation by broad-field LED illumination with the same spectral profile, increased both glial cells and neuronal calcium transient frequency and sEPSCs suggesting that few ChR2-transfected astrocytes were able to excite surrounding not-ChR2-transfected astrocytes and neurons. Finally, by using the μLEDs array to selectively light stimulate ChR2 positive astrocytes we were able to increase the synaptic activity of single neurons surrounding it. In conclusion, ChR2-transfected astrocytes and μLEDs system were shown to be an amplifier of synaptic activity in mixed corticalneuronal and glial cells culture.

  6. Arrays of microLEDs and astrocytes: biological amplifiers to optogenetically modulate neuronal networks reducing light requirement.

    Science.gov (United States)

    Berlinguer-Palmini, Rolando; Narducci, Roberto; Merhan, Kamyar; Dilaghi, Arianna; Moroni, Flavio; Masi, Alessio; Scartabelli, Tania; Landucci, Elisa; Sili, Maria; Schettini, Antonio; McGovern, Brian; Maskaant, Pleun; Degenaar, Patrick; Mannaioni, Guido

    2014-01-01

    In the modern view of synaptic transmission, astrocytes are no longer confined to the role of merely supportive cells. Although they do not generate action potentials, they nonetheless exhibit electrical activity and can influence surrounding neurons through gliotransmitter release. In this work, we explored whether optogenetic activation of glial cells could act as an amplification mechanism to optical neural stimulation via gliotransmission to the neural network. We studied the modulation of gliotransmission by selective photo-activation of channelrhodopsin-2 (ChR2) and by means of a matrix of individually addressable super-bright microLEDs (μLEDs) with an excitation peak at 470 nm. We combined Ca2+ imaging techniques and concurrent patch-clamp electrophysiology to obtain subsequent glia/neural activity. First, we tested the μLEDs efficacy in stimulating ChR2-transfected astrocyte. ChR2-induced astrocytic current did not desensitize overtime, and was linearly increased and prolonged by increasing μLED irradiance in terms of intensity and surface illumination. Subsequently, ChR2 astrocytic stimulation by broad-field LED illumination with the same spectral profile, increased both glial cells and neuronal calcium transient frequency and sEPSCs suggesting that few ChR2-transfected astrocytes were able to excite surrounding not-ChR2-transfected astrocytes and neurons. Finally, by using the μLEDs array to selectively light stimulate ChR2 positive astrocytes we were able to increase the synaptic activity of single neurons surrounding it. In conclusion, ChR2-transfected astrocytes and μLEDs system were shown to be an amplifier of synaptic activity in mixed corticalneuronal and glial cells culture.

  7. The development of a colour liquid crystal display spatial light modulator and applications in polychromatic optical data processing

    Science.gov (United States)

    Aiken, John Charles

    The development of a colour Spatial Light Modulator (SLM) and its application to optical information processing is described. Whilst monochrome technology has been established for many years, this is not the case for colour where commercial systems are unavailable. A main aspect of this study is therefore, how the use of colour can add an additional dimension to optical information processing. A well established route to monochrome system development has been the use of (black and white) liquid crystal televisions (LCTV) as SLM, providing useful performance at a low-cost. This study is based on the unique use of a colour display removed from a LCTV and operated as a colour SLM. A significant development has been the replacement of the original TV electronics operating the display with enhanced drive electronics specially developed for this application. Through a computer interface colour images from a drawing package or video camera can now be readily displayed on the LCD as input to an optical system. A detailed evaluation of the colour LCD optical properties, indicates that the new drive electronics have considerably improved the operation of the display for use as a colour SLM. Applications are described employing the use of colour in Fourier plane filtering, image correlation and speckle metrology. The SLM (and optical system) developed demonstrates, how the addition of colour has greatly enhanced its capabilities to implement principles of optical data processing, conventionally performed monochromatically. The hybrid combination employed, combining colour optical data processing with electronic techniques has resulted in a capable development system. Further development of the system using current colour LCDs and the move towards a portable system, is considered in the study conclusion.

  8. Investigating light curve modulation via kernel smoothing. I. Application to 53 fundamental mode and first-overtone Cepheids in the LMC

    Science.gov (United States)

    Süveges, Maria; Anderson, Richard I.

    2018-03-01

    Context. Recent studies have revealed a hitherto unknown complexity of Cepheid pulsations by discovering irregular modulated variability using photometry, radial velocities, and interferometry. Aim. We aim to perform a statistically rigorous search and characterization of such phenomena in continuous time, applying it to 53 classical Cepheids from the OGLE-III catalog. Methods: We have used local kernel regression to search for both period and amplitude modulations simultaneously in continuous time and to investigate their detectability. We determined confidence intervals using parametric and non-parametric bootstrap sampling to estimate significance, and investigated multi-periodicity using a modified pre-whitening approach that relies on time-dependent light curve parameters. Results: We find a wide variety of period and amplitude modulations and confirm that first overtone pulsators are less stable than fundamental mode Cepheids. Significant temporal variations in period are more frequently detected than those in amplitude. We find a range of modulation intensities, suggesting that both amplitude and period modulations are ubiquitous among Cepheids. Over the 12-year baseline offered by OGLE-III, we find that period changes are often nonlinear, sometimes cyclic, suggesting physical origins beyond secular evolution. Our method detects modulations (period and amplitude) more efficiently than conventional methods that are reliant on certain features in the Fourier spectrum, and pre-whitens time series more accurately than using constant light curve parameters, removing spurious secondary peaks effectively. Conclusions: Period and amplitude modulations appear to be ubiquitous among Cepheids. Current detectability is limited by observational cadence and photometric precision: detection of amplitude modulation below 3 mmag requires space-based facilities. Recent and ongoing space missions (K2, BRITE, MOST, CoRoT) as well as upcoming ones (TESS, PLATO) will

  9. Control of liquid crystal molecular orientation using ultrasound vibration

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Satoki [Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Koyama, Daisuke; Matsukawa, Mami [Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Faculty of Science and Engineering, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Shimizu, Yuki; Emoto, Akira [Faculty of Science and Engineering, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Nakamura, Kentaro [Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259-R2-26, Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)

    2016-03-07

    We propose a technique to control the orientation of nematic liquid crystals using ultrasound and investigate the optical characteristics of the oriented samples. An ultrasonic liquid crystal cell with a thickness of 5–25 μm and two ultrasonic lead zirconate titanate transducers was fabricated. By exciting the ultrasonic transducers, the flexural vibration modes were generated on the cell. An acoustic radiation force to the liquid crystal layer was generated, changing the molecular orientation and thus the light transmission. By modulating the ultrasonic driving frequency and voltage, the spatial distribution of the molecular orientation of the liquid crystals could be controlled. The distribution of the transmitted light intensity depends on the thickness of the liquid crystal layer because the acoustic field in the liquid crystal layer is changed by the orientational film.

  10. A light-driven modulation of electric conductance through the adsorption of azobenzene onto silicon-doped- and pyridine-like N3-vacancy graphene.

    Science.gov (United States)

    Zhao, Jun; Liu, Chunyan; Ma, Jing

    2017-12-14

    The ability to modulate the conductance of an electronic device under light irradiation is crucial to the practical applications of nanoscale electronics. Density functional theory calculations predict that the conductance of the photo-responsive graphene-based nanocomposites can be tuned through the noncovalent adsorption of an azobenzene (AB) derivative onto pristine, Si-doped, and pyridine-like N 3 -vacancy graphene. AB@graphene systems were found to exhibit a visible-light response within the low-frequency region, rendering the trans-to-cis isomerizations of these nanocomposites under the irradiation of solar light. The excellent solar light absorption performances of these hybrids can then be used to modulate the conductance of both N 3 -vacancy- and Si-doped-graphene AB hybrids effectively through the reversible change of the effective conjugate length of the AB molecule in the photoisomerization. In addition, the solar thermal energy up to 1.53 eV per AB molecule can be stored in the designed nanocomposites with the doped graphene. These findings provide clues for making multifunctional materials with potential applications as both optically controlled nanoelectronics and solar energy storage devices.

  11. Unpowered wireless transmission of ultrasound signals

    International Nuclear Information System (INIS)

    Huang, H; Paramo, D; Deshmukh, S

    2011-01-01

    This paper presents a wireless ultrasound sensing system that uses frequency conversion to convert the ultrasound signal to a microwave signal and transmit it directly without digitization. Constructed from a few passive microwave components, the sensor is able to sense, modulate, and transmit the full waveform of ultrasound signals wirelessly without requiring any local power source. The principle of operation of the unpowered wireless ultrasound sensor is described first, and this is followed by a detailed description of the implementation of the sensor and the sensor interrogation unit using commercially available antennas and microwave components. Validation of the sensing system using an ultrasound pitch–catch system and the power analysis model of the system are also presented

  12. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... of page How is the procedure performed? For most ultrasound exams, you will be positioned lying face- ... Ultrasound examinations are painless and easily tolerated by most patients. Ultrasound exams in which the transducer is ...

  13. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  14. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... medical test that helps physicians diagnose and treat medical conditions. Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ...

  15. Ultrasound guided supraclavicular block.

    LENUS (Irish Health Repository)

    Hanumanthaiah, Deepak

    2013-09-01

    Ultrasound guided regional anaesthesia is becoming increasingly popular. The supraclavicular block has been transformed by ultrasound guidance into a potentially safe superficial block. We reviewed the techniques of performing supraclavicular block with special focus on ultrasound guidance.

  16. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... D images. A Doppler ultrasound study may be part of an ultrasound examination. Doppler ultrasound , also called ... terms of the distance traveled per unit of time, rather than as a color picture. It can ...

  17. Validity and reliability of a structured-light 3D scanner and an ultrasound imaging system for measurements of facial skin thickness.

    Science.gov (United States)

    Lee, Kang-Woo; Kim, Sang-Hwan; Gil, Young-Chun; Hu, Kyung-Seok; Kim, Hee-Jin

    2017-10-01

    Three-dimensional (3 D)-scanning-based morphological studies of the face are commonly included in various clinical procedures. This study evaluated validity and reliability of a 3 D scanning system by comparing the ultrasound (US) imaging system versus the direct measurement of facial skin. The facial skin thickness at 19 landmarks was measured using the three different methods in 10 embalmed adult Korean cadavers. Skin thickness was first measured using the ultrasound device, then 3 D scanning of the facial skin surface was performed. After the skin on the left half of face was gently dissected, deviating slightly right of the midline, to separate it from the subcutaneous layer, and the harvested facial skin's thickness was measured directly using neck calipers. The dissected specimen was then scanned again, then the scanned images of undissected and dissected faces were superimposed using Morpheus Plastic Solution (version 3.0) software. Finally, the facial skin thickness was calculated from the superimposed images. The ICC value for the correlations between the 3 D scanning system and direct measurement showed excellent reliability (0.849, 95% confidence interval = 0.799-0.887). Bland-Altman analysis showed a good level of agreement between the 3 D scanning system and direct measurement (bias = 0.49 ± 0.49 mm, mean±SD). These results demonstrate that the 3 D scanning system precisely reflects structural changes before and after skin dissection. Therefore, an in-depth morphological study using this 3 D scanning system could provide depth data about the main anatomical structures of face, thereby providing crucial anatomical knowledge for utilization in various clinical applications. Clin. Anat. 30:878-886, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Observation Platform for Dynamic Biomedical and Biotechnology Experiments Using the International Space Station (ISS) Light Microscopy Module (LMM)

    Science.gov (United States)

    Kurk, Michael A. (Andy)

    2015-01-01

    Techshot, Inc., has developed an observation platform for the LMM on the ISS that will enable biomedical and biotechnology experiments. The LMM Dynamic Stage consists of an electronics module and the first two of a planned suite of experiment modules. Specimens and reagent solutions can be injected into a small, hollow microscope slide-the heart of the innovation-via a combination of small reservoirs, pumps, and valves. A life science experiment module allows investigators to load up to two different fluids for on-orbit, real-time image cytometry. Fluids can be changed to initiate a process, fix biological samples, or retrieve suspended cells. A colloid science experiment module conducts microparticle and nanoparticle tests for investigation of colloid self-assembly phenomena. This module includes a hollow glass slide and heating elements for the creation of a thermal gradient from one end of the slide to the other. The electronics module supports both experiment modules and contains a unique illuminator/condenser for bright and dark field and phase contrast illumination, power supplies for two piezoelectric pumps, and controller boards for pumps and valves. This observation platform safely contains internal fluids and will greatly accelerate the research and development (R&D) cycle of numerous experiments, products, and services aboard the ISS.

  19. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Conventional ultrasound displays the images in thin, ...

  20. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... and treat medical conditions. Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional (3- ...

  1. Pseudo-Random Modulation of a Laser Diode for Generating Ultrasonic Longitudinal Waves

    Science.gov (United States)

    Madaras, Eric I.; Anatasi, Robert F.

    2004-01-01

    Laser generated ultrasound systems have historically been more complicated and expensive than conventional piezoelectric based systems, and this fact has relegated the acceptance of laser based systems to niche applications for which piezoelectric based systems are less suitable. Lowering system costs, while improving throughput, increasing ultrasound signal levels, and improving signal-to-noise are goals which will help increase the general acceptance of laser based ultrasound. One current limitation with conventional laser generated ultrasound is a material s damage threshold limit. Increasing the optical power to generate more signal eventually damages the material being tested due to rapid, high heating. Generation limitations for laser based ultrasound suggests the use of pulse modulation techniques as an alternate generation method. Pulse modulation techniques can spread the laser energy over time or space, thus reducing laser power densities and minimizing damage. Previous experiments by various organizations using spatial or temporal pulse modulation have been shown to generate detectable surface, plate, and bulk ultrasonic waves with narrow frequency bandwidths . Using narrow frequency bandwidths improved signal detectability, but required the use of expensive and powerful lasers and opto-electronic systems. The use of a laser diode to generate ultrasound is attractive because of its low cost, small size, light weight, simple optics and modulation capability. The use of pulse compression techniques should allow certain types of laser diodes to produce usable ultrasonic signals. The method also does not need to be limited to narrow frequency bandwidths. The method demonstrated here uses a low power laser diode (approximately 150 mW) that is modulated by controlling the diode s drive current and the resulting signal is recovered by cross correlation. A potential application for this system which is briefly demonstrated is in detecting signals in thick

  2. A passive wireless ultrasound pitch–catch system

    International Nuclear Information System (INIS)

    Zahedi, F; Yao, J; Huang, H

    2015-01-01

    This paper exploits amplitude modulation and demodulation to achieve a passive wireless ultrasound pitch–catch system consisting of a wireless interrogator and a combination of a wireless actuator and a sensor mounted on a structure. The wireless interrogator operates in two modes, i.e. the generation and sensing modes. At the generation mode, the interrogator transmits two microwave signals; one is amplitude modulated with the ultrasound excitation signal while the other is a continuous-wave carrier signal. Once received by the wireless actuator, the amplitude modulated signal is demodulated using the carrier signal to recover the ultrasound excitation signal, which is then supplied to a piezoelectric wafer actuator for ultrasound generation. Subsequently, the interrogator is switched to the sensing mode by transmitting a carrier signal with a different frequency. Once received by the wireless sensor, this carrier signal is modulated with the ultrasound sensing signal acquired by the piezoelectric wafer sensor to produce an amplitude modulated microwave signal, which can then be wirelessly transmitted and demodulated by the interrogator to recover the original ultrasound sensing signal. The principle and implementation of the wireless ultrasound pitch–catch system as well as the data processing of the wirelessly received sensing signal are described. Experiment results validating wireless ultrasound generation and sensing from a distance of 0.5 m are presented. (paper)

  3. Light-Induced Fluorescence Modulation of Quantum Dot-Crystal Violet Conjugates: Stochastic Off-On-Off Cycles for Multicolor Patterning and Super-Resolution.

    Science.gov (United States)

    Jung, Sungwook; Park, Joonhyuck; Bang, Jiwon; Kim, Jae-Yeol; Kim, Cheolhee; Jeon, Yongmoon; Lee, Seung Hwan; Jin, Ho; Choi, Sukyung; Kim, Bomi; Lee, Woo Jin; Pack, Chan-Gi; Lee, Jong-Bong; Lee, Nam Ki; Kim, Sungjee

    2017-06-07

    Photoswitching or modulation of quantum dots (QDs) can be promising for many fields that include display, memory, and super-resolution imaging. However, such modulations have mostly relied on photomodulations of conjugated molecules in QD vicinity, which typically require high power of high energy photons at UV. We report a visible light-induced facile modulation route for QD-dye conjugates. QD crystal violets conjugates (QD-CVs) were prepared and the crystal violet (CV) molecules on QD quenched the fluorescence efficiently. The fluorescence of QD-CVs showed a single cycle of emission burst as they go through three stages of (i) initially quenched "off" to (ii) photoactivated "on" as the result of chemical change of CVs induced by photoelectrons from QD and (iii) back to photodarkened "off" by radical-associated reactions. Multicolor on-demand photopatterning was demonstrated using QD-CV solid films. QD-CVs were introduced into cells, and excitation with visible light yielded photomodulation from "off" to "on" and "off" by nearly ten fold. Individual photoluminescence dynamics of QD-CVs was investigated using fluorescence correlation spectroscopy and single QD emission analysis, which revealed temporally stochastic photoactivations and photodarkenings. Exploiting the stochastic fluorescence burst of QD-CVs, simultaneous multicolor super-resolution localizations were demonstrated.

  4. Vascular ultrasound.

    Science.gov (United States)

    Pilcher, D B; Ricci, M A

    1998-04-01

    Surgeon-interpreted diagnostic ultrasound has become the preferred screening test and often the definitive test for the diagnosis of arterial stenosis, aneurysm, and venous thrombosis. As a modality for surveillance, its noninvasive quality makes it particularly appealing as the test of choice to screen patients for abdominal aortic aneurysms or to perform follow-up examinations on those patients with a carotid endartectomy or in situ bypass grafts. The increasing reliance on intraoperative duplex imaging of vascular procedures demands that the surgeon learn the skills to perform the studies without a technologist or radiologist to interpret the examination.

  5. Light-curve Modulation of Low-mass Stars in K2. I. Identification of 481 Fast Rotators in the Solar Neighborhood

    Science.gov (United States)

    Saylor, Dicy; Lepine, Sebastien; Crossfield, Ian; Petigura, Erik A.

    2018-01-01

    The K2 mission is targeting large numbers of nearby (d 40 mas yr‑1, V < 20). Additionally, the mission is targeting low-mass, high proper motion stars associated with the local (d < 500 pc) Galactic halo population also selected from SUPERBLINK. K2 campaigns 0 through 8 monitored a total of 26,518 of these cool main-sequence stars. We used the auto-correlation function to search for fast rotators by identifying short-period photometric modulations in the K2 light curves. We identified 481 candidate fast rotators with rotation periods <4 days that show light-curve modulations consistent with starspots. Their kinematics show low average transverse velocities, suggesting that they are part of the young disk population. A subset (13) of the fast rotators is found among those targets with colors and kinematics consistent with the local Galactic halo population and may represent stars spun up by tidal interactions in close binary systems. We further demonstrate that the M dwarf fast rotators selected from the K2 light curves are significantly more likely to have UV excess and discuss the potential of the K2 mission to identify new nearby young GKM dwarfs on the basis of their fast rotation rates. Finally, we discuss the possible use of local halo stars as fiducial, non-variable sources in the Kepler fields.

  6. Single particle characterization using a light scattering module coupled to a time-of-flight aerosol mass spectrometer

    Science.gov (United States)

    Cross, E. S.; Onasch, T. B.; Canagaratna, M.; Jayne, J. T.; Kimmel, J.; Yu, X.-Y.; Alexander, M. L.; Worsnop, D. R.; Davidovits, P.

    2008-12-01

    We present the first single particle results obtained using an Aerodyne time-of-flight aerosol mass spectrometer coupled with a light scattering module (LS-ToF-AMS). The instrument was deployed at the T1 ground site approximately 40 km northeast of the Mexico City Metropolitan Area (MCMA) as part of the MILAGRO field study in March of 2006. The instrument was operated as a standard AMS from 12-30 March, acquiring average chemical composition and size distributions for the ambient aerosol, and in single particle mode from 27-30 March. Over a 75-h sampling period, 12 853 single particle mass spectra were optically triggered, saved, and analyzed. The correlated optical and chemical detection allowed detailed examination of single particle collection and quantification within the LS-ToF-AMS. The single particle data enabled the mixing states of the ambient aerosol to be characterized within the context of the size-resolved ensemble chemical information. The particulate mixing states were examined as a function of sampling time and most of the particles were found to be internal mixtures containing many of the organic and inorganic species identified in the ensemble analysis. The single particle mass spectra were deconvolved, using techniques developed for ensemble AMS data analysis, into HOA, OOA, NH4NO3, (NH4)2SO4, and NH4Cl fractions. Average single particle mass and chemistry measurements are shown to be in agreement with ensemble MS and PTOF measurements. While a significant fraction of ambient particles were internal mixtures of varying degrees, single particle measurements of chemical composition allowed the identification of time periods during which the ambient ensemble was externally mixed. In some cases the chemical composition of the particles suggested a likely source. Throughout the full sampling period, the ambient ensemble was an external mixture of combustion-generated HOA particles from local sources (e.g. traffic), with number concentrations peaking

  7. Voltage balancing: Long-term experience with the 250 V supercapacitor module of the hybrid fuel cell vehicle HY-LIGHT

    Energy Technology Data Exchange (ETDEWEB)

    Koetz, R.; Sauter, J.-C.; Ruch, P.; Dietrich, P.; Buechi, F.N. [Paul Scherrer Institut, Electrochemistry Laboratory, CH-5232 Villigen PSI (Switzerland); Magne, P.A.; Varenne, P. [Conception et Developpement Michelin SA, CH-1762 Givisiez (Switzerland)

    2007-11-22

    On the occasion of the ''Challenge Bibendum'' 2004 in Shanghai, the hybrid fuel cell - supercapacitor vehicle HY-LIGHT, a joint project of Conception et Developpement Michelin and the Paul Scherrer Institut, was presented to the public. The drive train of this vehicle comprises a 30 kW polymer electrolyte fuel cell (PEFC) and a 250 V supercapacitor (SC) module for energy recuperation and boost power during short acceleration and start-up processes. The supercapacitor module was deliberately constructed without continuous voltage balancing units. The performance of the supercapacitor module was monitored over the 2 years of operation particularly with respect to voltage balancing of the large number of SC cells connected in series. During the investigated period of 19 months and about 7000 km driving, the voltage imbalance within the supercapacitor module proved negligible. The maximum deviation between best and worst SC was always below 120 mV and the capacitor with the highest voltage never exceeded the nominal voltage by more than 40 mV. (author)

  8. Ultrasound assisted synthesis of morphology tunable rGO:ZnO hybrid nanostructures and their optical and UV-A light driven photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Thangaraj, Pandiyarajan, E-mail: rtpandiyarajan@gmail.com [Advanced Ceramics and Nanotechnology Laboratory, Department of Materials Engineering, University of Concepcion (Chile); Ramalinga Viswanathan, Mangalaraja, E-mail: mangal@udec.cl [Advanced Ceramics and Nanotechnology Laboratory, Department of Materials Engineering, University of Concepcion (Chile); Balasubramanian, Karthikeyan [Department of Physics, National Institute of Technology, Tiruchirappalli 620015 (India); Mansilla, Héctor D. [Departament of Organic Chemistry, Faculty of Chemical Sciences, University of Concepcion (Chile); Contreras, David [Departament of Analytical and Inorganic Chemistry, Faculty of Chemical Sciences, Center for Biotechnology, University of Concepcion (Chile); Sepulveda-Guzman, Selene [Universidad Autónoma de Nuevo León, UANL, Facultad de Ingeniería Mecánica y Eléctrica, FIME, Ave. Pedro de Alba s/n, Ciudad Universitaria, C.P.66455 San Nicolás de los Garza, N.L. (Mexico); Gracia-Pinilla, M.A. [Universidad Autónoma de Nuevo León, Facultad de Ciencias Físico-Matemáticas, Av. Universidad, Cd. Universitaria, San Nicolás de los Garza, NL (Mexico); Centro de Investigación en Innovación y Desarrollo en Ingeniería y Tecnología, Universidad Autónoma de Nuevo León, PIIT, Apodaca, Nuevo León 66600 (Mexico)

    2017-06-15

    Controlling size and shape of hybrid nanostructures is technologically important because of the strong effect of nanostructure dimension and morphology on optoelectronic, biosensors and catalytic properties. Here, we have demonstrated a simple strategy for simultaneous control of morphology, defect engineering and photocatalytic activities of reduced graphene oxide:zinc oxide (rGO:ZnO) hybrid nanostructures which were prepared by using low frequency (42 kHz) ultrasound. By varying the solvents, the morphology of ZnO gradually evolved from spherical shape to a star like nature and the ZnO nanoparticles decorated on reduced graphene oxide were clearly observed in the TEM analysis. Absorption, photoluminescence, Raman and FTIR spectra clearly indicated the formation of rGO:ZnO hybrid nanostructures. Thermal analysis revealed that the hybrid nanostructures exhibited a good thermal stability. The synergistic integration of the unique morphology and size imparts the rGO:ZnO hybrid nanostructures with remarkably enhanced photocatalytic efficiency when compared with bare ZnO. The enhanced photocatalytic behaviour of the rGO:ZnO composite has been discussed in details herein. Simple and facile synthesis route demonstrated the potential for the utilization of rGO:ZnO hybrid nanostructures with unique properties for environmental engineering applications.

  9. p-Type modulation doped InGaN/GaN dot-in-a-wire white-light-emitting diodes monolithically grown on Si(111).

    Science.gov (United States)

    Nguyen, H P T; Zhang, S; Cui, K; Han, X; Fathololoumi, S; Couillard, M; Botton, G A; Mi, Z

    2011-05-11

    Full-color, catalyst-free InGaN/GaN dot-in-a-wire light-emitting diodes (LEDs) were monolithically grown on Si(111) by molecular beam epitaxy, with the emission characteristics controlled by the dot properties in a single epitaxial growth step. With the use of p-type modulation doping in the dot-in-a-wire heterostructures, we have demonstrated the most efficient phosphor-free white LEDs ever reported, which exhibit an internal quantum efficiency of ∼56.8%, nearly unaltered CIE chromaticity coordinates with increasing injection current, and virtually zero efficiency droop at current densities up to ∼640 A/cm(2). The remarkable performance is attributed to the superior three-dimensional carrier confinement provided by the electronically coupled dot-in-a-wire heterostructures, the nearly defect- and strain-free GaN nanowires, and the significantly enhanced hole transport due to the p-type modulation doping.

  10. Four-photon parametric light scattering of ultrashort laser pulses in water in case of weak self-phase modulation

    International Nuclear Information System (INIS)

    Babenko, V A; Sychev, Andrei A

    2009-01-01

    The hyper-Raman scattering (HRS) of light in water is detected reliably by the active spectroscopy method of coherent light scattering, in particular, by the method of four-photon parametric light scattering in a medium in which HRS is a 'signal' wave in the parametric process involving simultaneously two high-power laser photons and IR photons of an 'idler' wave. Hyper-Raman scattering by libration vibrations of water molecules, which virtually cannot be detected by conventional methods of Raman scattering, was observed. (nonlinear optical phenomena)

  11. THE DISCOVERY OF PERIODIC MODULATIONS IN THE OPTICAL SPECTRA OF GALAXIES, POSSIBLY DUE TO ULTRARAPID LIGHT BURSTS FROM THEIR MASSIVE CENTRAL BLACK HOLES

    Energy Technology Data Exchange (ETDEWEB)

    Borra, Ermanno F., E-mail: borra@phy.ulaval.ca [Centre d' Optique, Photonique et Laser, Departement de Physique, Universite Laval, Quebec, G1K 7P4 Quebec (Canada)

    2013-09-10

    A Fourier transform analysis of 2.5 million spectra in the SDSS survey was carried out to detect periodic modulations contained in the intensity versus frequency spectrum. A statistically significant signal was found for 223 galaxies, while the spectra of 0.9 million galaxies were observed. A plot of the periods as a function of redshift clearly shows that the effect is real without any doubt, because the modulations are quantized at two base periods that increase with redshift in two very tight parallel linear relations. We suggest that this result could be caused by light bursts separated by times on the order of 10{sup -13} s, but other causes may be possible. We investigate the hypothesis that the modulation is generated by the Fourier transform of spectral lines, but conclude that this hypothesis is not valid. Although the light burst suggestion implies absurdly high temperatures, it is supported by the fact that the Crab pulsar also has extremely short unresolved pulses (<0.5 ns) that imply similarly high temperatures. Furthermore, the radio spectrum of the Crab pulsar also has spectral bands similar to those that have been detected. Finally, decreasing the signal-to-noise threshold of detection gives results consistent with beamed signals having a small beam divergence, as expected from non-thermal sources that send a jet, like those seen in pulsars. Considering that galaxy centers contain massive black holes, exotic black hole physics may be responsible for the spectral modulation. However, at this stage, this idea is only a hypothesis to be confirmed with further work.

  12. Trinary arithmetic and logic unit (TALU) using savart plate and spatial light modulator (SLM) suitable for optical computation in multivalued logic

    Science.gov (United States)

    Ghosh, Amal K.; Bhattacharya, Animesh; Raul, Moumita; Basuray, Amitabha

    2012-07-01

    Arithmetic logic unit (ALU) is the most important unit in any computing system. Optical computing is becoming popular day-by-day because of its ultrahigh processing speed and huge data handling capability. Obviously for the fast processing we need the optical TALU compatible with the multivalued logic. In this regard we are communicating the trinary arithmetic and logic unit (TALU) in modified trinary number (MTN) system, which is suitable for the optical computation and other applications in multivalued logic system. Here the savart plate and spatial light modulator (SLM) based optoelectronic circuits have been used to exploit the optical tree architecture (OTA) in optical interconnection network.

  13. The imprints of the high light and UV-B stresses in Oryza sativa L. 'Kanchana' seedlings are differentially modulated.

    Science.gov (United States)

    Faseela, Parammal; Puthur, Jos T

    2018-01-01

    High light and ultraviolet-B radiation (UV-B) are generally considered to have negative impact on photosynthesis and plant growth. The present study evaluates the tolerance potential of three cultivars of Oryza sativa L. (Kanchana, Mattatriveni and Harsha) seedlings towards high light and UV-B stress on the basis of photosynthetic pigment degradation, chlorophyll a fluorescence parameters and rate of lipid peroxidation, expressed by malondialdehyde content. Surprisingly, it was revealed that Kanchana was the most sensitive cultivar towards high light and at the same time it was the most tolerant cultivar towards UV-B stress. This contrasting feature of Kanchana towards high light and UV-B tolerance was further studied by analyzing photosystem (PS) I and II activity, mitochondrial activity, chlorophyll a fluorescence transient, enzymatic and non-enzymatic antioxidant defense system. Due to the occurrence of more PS I and PSII damages, the inhibition of photochemical efficiency and emission of dissipated energy as heat or fluorescence per PSII reaction center was higher upon high light exposure than UV-B treatments in rice seedlings of Kanchana. The mitochondrial activity was also found to be drastically altered upon high light as compared to UV-B treatments. The UV-B induced accumulation of non-enzymatic antioxidants (proline, total phenolics, sugar and ascorbate) and enzymatic antioxidants (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and glutathione reductase) in rice seedlings than those subjected to high light exposure afforded more efficient protection against UV-B radiation in rice seedlings. Our results proved that high tolerance of Kanchana towards UV-B than high light treatments, correlated linearly with the protected photosynthetic and mitochondrial machinery which was provided by upregulation of antioxidants particularly by total phenolics, ascorbate and ascorbate peroxidase in rice seedlings. Data presented in this study conclusively

  14. New intelligent multifunctional SiO2/VO2 composite films with enhanced infrared light regulation performance, solar modulation capability, and superhydrophobicity.

    Science.gov (United States)

    Wang, Chao; Zhao, Li; Liang, Zihui; Dong, Binghai; Wan, Li; Wang, Shimin

    2017-01-01

    Highly transparent, energy-saving, and superhydrophobic nanostructured SiO 2 /VO 2 composite films have been fabricated using a sol-gel method. These composite films are composed of an underlying infrared (IR)-regulating VO 2 layer and a top protective layer that consists of SiO 2 nanoparticles. Experimental results showed that the composite structure could enhance the IR light regulation performance, solar modulation capability, and hydrophobicity of the pristine VO 2 layer. The transmittance of the composite films in visible region ( T lum ) was higher than 60%, which was sufficient to meet the requirements of glass lighting. Compared with pristine VO 2 films and tungsten-doped VO 2 film, the near IR control capability of the composite films was enhanced by 13.9% and 22.1%, respectively, whereas their solar modulation capability was enhanced by 10.9% and 22.9%, respectively. The water contact angles of the SiO 2 /VO 2 composite films were over 150°, indicating superhydrophobicity. The transparent superhydrophobic surface exhibited a high stability toward illumination as all the films retained their initial superhydrophobicity even after exposure to 365 nm light with an intensity of 160 mW . cm -2 for 10 h. In addition, the films possessed anti-oxidation and anti-acid properties. These characteristics are highly advantageous for intelligent windows or solar cell applications, given that they can provide surfaces with anti-fogging, rainproofing, and self-cleaning effects. Our technique offers a simple and low-cost solution to the development of stable and visible light transparent superhydrophobic surfaces for industrial applications.

  15. Ultrasound in Space Medicine

    Science.gov (United States)

    Dulchavsky, Scott A.; Sargsyan, A.E.

    2009-01-01

    This slide presentation reviews the use of ultrasound as a diagnostic tool in microgravity environments. The goals of research in ultrasound usage in space environments are: (1) Determine accuracy of ultrasound in novel clinical conditions. (2) Determine optimal training methodologies, (3) Determine microgravity associated changes and (4) Develop intuitive ultrasound catalog to enhance autonomous medical care. Also uses of Ultrasound technology in terrestrial applications are reviewed.

  16. A new path in defining light parameters for hair growth: Discovery and modulation of photoreceptors in human hair follicle.

    Science.gov (United States)

    Buscone, Serena; Mardaryev, Andrei N; Raafs, Bianca; Bikker, Jan W; Sticht, Carsten; Gretz, Norbert; Farjo, Nilofer; Uzunbajakava, Natallia E; Botchkareva, Natalia V

    2017-09-01

    Though devices for hair growth based on low levels of light have shown encouraging results, further improvements of their efficacy is impeded by a lack of knowledge on the exact molecular targets that mediate physiological response in skin and hair follicle. The aim of this study was to investigate the expression of selected light-sensitive receptors in the human hair follicle and to study the impact of UV-free blue light on hair growth ex vivo. The expression of Opsin receptors in human skin and hair follicles has been characterized using RT-qPCR and immunofluorescence approaches. The functional significance of Opsin 3 was assessed by silencing its expression in the hair follicle cells followed by a transcriptomic profiling. Proprietary LED-based devices emitting two discrete visible wavelengths were used to access the effects of selected optical parameters on hair growth ex vivo and outer root sheath cells in vitro. The expression of OPN2 (Rhodopsin) and OPN3 (Panopsin, Encephalopsin) was detected in the distinct compartments of skin and anagen hair follicle. Treatment with 3.2 J/cm 2 of blue light with 453 nm central wavelength significantly prolonged anagen phase in hair follicles ex vivo that was correlated with sustained proliferation in the light-treated samples. In contrast, hair follicle treatment with 3.2 J/cm 2 of 689 nm light (red light) did not significantly affect hair growth ex vivo. Silencing of OPN3 in the hair follicle outer root sheath cells resulted in the altered expression of genes involved in the control of proliferation and apoptosis, and abrogated stimulatory effects of blue light (3.2 J/cm 2 ; 453 nm) on proliferation in the outer root sheath cells. We provide the first evidence that (i) OPN2 and OPN3 are expressed in human hair follicle, and (ii) A 453 nm blue light at low radiant exposure exerts a positive effect on hair growth ex vivo, potentially via interaction with OPN3. Lasers Surg. Med. 49:705-718, 2017. © 2017 Wiley

  17. Exposure to blue wavelength light modulates anterior cingulate cortex activation in response to 'uncertain' versus 'certain' anticipation of positive stimuli.

    Science.gov (United States)

    Alkozei, Anna; Smith, Ryan; Killgore, William D S

    2016-03-11

    Blue wavelength light has been used as an effective treatment for some types of mood disorders and circadian rhythm related sleep problems. We hypothesized that acute exposure to blue wavelength light would directly affect the functioning of neurocircuity implicated in emotion regulation (i.e., ventromedial prefrontal cortex, amygdala, insula, and anterior cingulate cortex [ACC]) during 'certain' and 'uncertain' anticipation of negative and positive stimuli. Thirty-five healthy adults were randomized to receive a thirty-minute exposure to either blue (active) or amber (placebo) light, immediately followed by an emotional anticipation task during functional magnetic resonance imaging (fMRI). In contrast to placebo, participants in the blue light group showed significantly reduced activation within the rostral ACC during 'uncertain' anticipation (i.e., uncertainty regarding whether a positive or negative stimulus would be shown) in comparison to 'certain' anticipation of a positive stimulus. These findings may be explicable in terms of interactions between blue light exposure and the influence of specific neuromodulators on ACC-mediated decision-making mechanisms. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Modulation of the photoluminescence in carbon dots through surface modification: from mechanism to white light-emitting diodes

    Science.gov (United States)

    Zhu, Jinyang; Shao, He; Bai, Xue; Zhai, Yue; Zhu, Yongsheng; Chen, Xu; Pan, Gencai; Dong, Biao; Xu, Lin; Zhang, Hanzhuang; Song, Hongwei

    2018-06-01

    Carbon dots (CDs) have emerged as a new type of fluorescent material because of their unique optical advantages, such as high photoluminescence quantum yields (QYs), excellent photo-stability, excitation-dependent emissions, and low toxicity. However, the photoluminescence mechanism for CDs remains unclear, which limits their further practical application. Here, CDs were synthesized via a solvothermal route from citric acid and urea. Through the oxidation and reduction treatment of pristine CDs, the origin of the photoluminescence and the involved mechanism were revealed. We found that the blue/green/red emissions originated from three diverse emitting states, i.e. the intrinsic state, and C=O- and C=N-related surface states, respectively. Based on the as-prepared CDs, a pH sensor depending on the radiometric luminescence detection was developed. Furthermore, we constructed CD/PVP (PVP, polyvinylpyrrolidone) composite films, which exhibited white light emission with photoluminescence QYs of 15.3%. The white light emission with different correlated color temperatures (CCTs), from 4807 K to 3319 K, was obtained by simply changing the amount of PVP solution. Benefiting from the white light-emitting solid-state films, single-component white light-emitting diodes were fabricated with an average color rendering index value (Ra) of 80.0, luminous efficiency of 10.2 lm W‑1, and good working stability, thus indicating a promising potential for practical lighting applications.

  19. Paranode Abnormalities and Oxidative Stress in Optic Nerve Vulnerable to Secondary Degeneration: Modulation by 670 nm Light Treatment.

    Directory of Open Access Journals (Sweden)

    Charis R Szymanski

    Full Text Available Secondary degeneration of nerve tissue adjacent to a traumatic injury results in further loss of neurons, glia and function, via mechanisms that may involve oxidative stress. However, changes in indicators of oxidative stress have not yet been demonstrated in oligodendrocytes vulnerable to secondary degeneration in vivo. We show increases in the oxidative stress indicator carboxymethyl lysine at days 1 and 3 after injury in oligodendrocytes vulnerable to secondary degeneration. Dihydroethidium staining for superoxide is reduced, indicating endogenous control of this particular reactive species after injury. Concurrently, node of Ranvier/paranode complexes are altered, with significant lengthening of the paranodal gap and paranode as well as paranode disorganisation. Therapeutic administration of 670 nm light is thought to improve oxidative metabolism via mechanisms that may include increased activity of cytochrome c oxidase. Here, we show that light at 670 nm, delivered for 30 minutes per day, results in in vivo increases in cytochrome c oxidase activity co-localised with oligodendrocytes. Short term (1 day 670 nm light treatment is associated with reductions in reactive species at the injury site. In optic nerve vulnerable to secondary degeneration superoxide in oligodendrocytes is reduced relative to handling controls, and is associated with reduced paranode abnormalities. Long term (3 month administration of 670 nm light preserves retinal ganglion cells vulnerable to secondary degeneration and maintains visual function, as assessed by the optokinetic nystagmus visual reflex. Light at a wavelength of 670 nm may serve as a therapeutic intervention for treatment of secondary degeneration following neurotrauma.

  20. Effect of refraction index and light sharing on detector element identification for 2D detector modules in Positron Emission Tomography

    International Nuclear Information System (INIS)

    Tornai, M.P.; Hoffman, E.J.; Cherry, S.R.

    1994-01-01

    Relationships among indices of refraction (n) of scintillation detectors, light sharing among discrete detector elements and accuracy of detector element identification in Positron Emission Tomography (PET) 2-D detector arrays were examined with theory and experiment. Mismatches between the index of refraction of scintillators and the glass of photomultipliers (PMT) were seen to lead to nonlinear relationships between crystal position and ratio (positioning) signals derived from PMTs. Insight is provided into the empirically derived use of light sharing among elements of the crystals in PET 2-D array detectors to compensate for this nonlinear response. ((orig.))

  1. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication.

    Science.gov (United States)

    Lee, Changmin; Zhang, Chong; Cantore, Michael; Farrell, Robert M; Oh, Sang Ho; Margalith, Tal; Speck, James S; Nakamura, Shuji; Bowers, John E; DenBaars, Steven P

    2015-06-15

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature.

  2. Fault identification in crystalline silicon PV modules by complementary analysis of the light and dark current-voltage characteristics

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Hacke, Peter

    2014-01-01

    Photovoltaic system (PV) maintenance and diagnostic tools are often based on performance models of the system, complemented with light current-voltage (I-V) measurements, visual inspection and/or thermal imaging. Although these are invaluable tools in diagnosing PV system performance losses and f...

  3. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication

    KAUST Repository

    Lee, Changmin

    2015-06-10

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature.

  4. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication

    KAUST Repository

    Lee, Changmin; Zhang, Chong; Cantore, Michael; Farrell, Robert M.; Oh, Sang Ho; Margalith, Tal; Speck, James S.; Nakamura, Shuji; Bowers, John E.; DenBaars, Steven P.

    2015-01-01

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free

  5. Ultra-light and stable composite structure to support and cool the ATLAS pixel detector barrel electronics modules

    International Nuclear Information System (INIS)

    Olcese, M.; Caso, C.; Castiglioni, G.; Cereseto, R.; Cuneo, S.; Dameri, M.; Gemme, C.; Glitza, K.-W.; Lenzen, G.; Mora, F.; Netchaeva, P.; Ockenfels, W.; Piano, E.; Pizzorno, C.; Puppo, R.; Rebora, A.; Rossi, L.; Thadome, J.; Vernocchi, F.; Vigeolas, E.; Vinci, A.

    2004-01-01

    The design of an ultra light structure, the so-called 'stave', to support and cool the sensitive elements of the Barrel Pixel detector, the innermost part of the ATLAS detector to be installed on the new Large Hadron Collider at CERN (Geneva), is presented. Very high-dimensional stability, minimization of the material and ability of operating 10 years in a high radiation environment are the key design requirements. The proposed solution consists of a combination of different carbon-based materials (impregnated carbon-carbon, ultra high modulus carbon fibre composites) coupled to a thin aluminum tube to form a very light support with an integrated cooling channel. Our design has proven to successfully fulfil the requirements. The extensive prototyping and testing program to fully qualify the design and release the production are discussed

  6. Laser beam shaping limitations for laboratory simulation of turbulence using a phase-only spatial light modulator

    CSIR Research Space (South Africa)

    Litvin, IA

    2007-09-01

    Full Text Available ) where ],[ 10∈ρ and ],[ πθ 20∈ , in an infinite series of these polynomials will be complete. The circle polynomials of Zernike have the form of complex angular function modulated by a real radial polynomial: θρθρ immnmn eRnZ )()1....0 − ⎥⎥⎦ ⎤ ⎢⎢⎣ ⎡ = ∫ h h n dhhCkr , (8) where h is the height from some reference level, usually ground or sea level. The key parameter in the turbulence model is the refractive index structure constant, 2nC , which in general...

  7. Optical detection of ultrasound using an apertureless near-field scanning optical microscopy system

    Science.gov (United States)

    Ahn, Phillip; Zhang, Zhen; Sun, Cheng; Balogun, Oluwaseyi

    2013-01-01

    Laser ultrasonics techniques are power approaches for non-contact generation and detection of high frequency ultrasound on a local scale. In these techniques, optical diffraction limits the spatial information that can be accessed from a measurement. In order to improve the lateral spatial resolution, we incorporate an apertureless near-field scanning optical microscope (aNSOM) into laser ultrasonics setup for local detection of laser generated ultrasound. The aNSOM technique relies on the measurement of a weak backscattered near-field light intensity resulting from the oblique illumination of a nanoscale probe-tip positioned close to a sample surface. We enhance the optical near-field intensity by coupling light to surface plasmon polaritons (SPPs) on the shaft of an atomic force microscopy (AFM) cantilever. The SPPs propagate down the AFM shaft, localize at the tip apex, and are backscattered to the far-field when the separation distance between the probe tip and the sample surface is comparable to the probe-tip radius. The backscattered near-field intensity is dynamically modulated when an ultrasonic wave arrives at the sample surface leading to a transient change in the tip-sample separation distance. We present experimental results detailing measurement of broadband and narrowband laser generated ultrasound in solids with frequencies reaching up to 180 MHz range.

  8. Ultrasound guidance for internal jugular vein cannulation: Continuing Professional Development.

    Science.gov (United States)

    Ayoub, Christian; Lavallée, Catherine; Denault, André

    2010-05-01

    The objective of this continuing professional development module is to describe the role of ultrasound for central venous catheterization and to specify its benefits and limitations. Although ultrasound techniques are useful for all central venous access sites, the focus of this module is on the internal jugular vein approach. In recent years, several studies were published on the benefits of ultrasound use for central venous catheterization. This technique has evolved rapidly due to improvements in the equipment and technology available. Ultrasound helps to detect the anatomical variants of the internal jugular vein. The typical anterolateral position of the internal jugular vein with respect to the carotid is found in only 9-92% of cases. Ultrasound guidance reduces the rate of mechanical, infectious, and thrombotic complications by 57%, and it also reduces the failure rate by 86%. Cost-benefit analyses show that the cost of ultrasound equipment is compensated by the decrease in the expenses associated with the treatment of complications. In this article, we will review the history of ultrasound guidance as well as the reasons that account for its superiority over the classical anatomical landmark technique. We will describe the equipment needed for central venous catheterization as well as the various methods to visualize with ultrasound. To improve patient safety, we recommend the use of ultrasound for central venous catheterization using the internal jugular approach.

  9. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... size, shape and consistency (whether the object is solid or filled with fluid). In medicine, ultrasound is ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  10. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... procedure? Ultrasound examinations can help to diagnose a variety of conditions and to assess organ damage following ... the Ultrasound-Guided Breast Biopsy page . diagnose a variety of heart conditions, including valve problems and congestive ...

  11. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... 3-D) ultrasound that formats the sound wave data into 3-D images. A Doppler ultrasound study ... at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 ...

  12. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... 3-D) ultrasound that formats the sound wave data into 3-D images. A Doppler ultrasound study ... to do the scanning. The transducer is a small hand-held device that resembles a microphone, attached ...

  13. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... in infections With knowledge about the speed and volume of blood flow gained from a Doppler ultrasound ... the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. top of page ...

  14. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... color picture. It can also convert blood flow information into a distinctive sound that can be heard ...

  15. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... care physician, or to the physician or other healthcare provider who requested the exam. Usually, the referring ...

  16. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 ...

  17. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... top of page What are the benefits vs. risks? Benefits Most ultrasound scanning is noninvasive (no needles ... procedures such as needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known ...

  18. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... move through vessels. The movement of blood cells causes a change in pitch of the reflected sound ...

  19. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  20. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... possible charges you will incur. Web page review process: This Web page is reviewed regularly by a ...