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Sample records for optically controlled three-dimensional

  1. Three-dimensional shape optical measurement using constant gap control and error compensation

    SciTech Connect

    Park, Kyihwan; Kim, Sangyoo; Choi, Kyosoon

    2008-03-15

    The optical laser displacement sensor is widely used for noncontact measurement of the three-dimensional (3D) shape profile of the object surface. When the surface of an object has a slope variation, the sensor gain is proportionally varied according to that of the object surface. In order to solve the sensor gain variation problem, the constant gap control method is applied to adjust the gap to the nominal distance. Control error compensation is also proposed to cope with the situation even when the gap is not perfectly controlled to the nominal distance using an additional sensor attached to the actuator. 3D shape measurement applying the proposed constant gap control method shows better performances rather than the constant sensor height method.

  2. Three-dimensional rearrangement of single atoms using actively controlled optical microtraps.

    PubMed

    Lee, Woojun; Kim, Hyosub; Ahn, Jaewook

    2016-05-01

    We propose and demonstrate three-dimensional rearrangements of single atoms. In experiments performed with single 87Rb atoms in optical microtraps actively controlled by a spatial light modulator, we demonstrate various dynamic rearrangements of up to N = 9 atoms including rotation, 2D vacancy filling, guiding, compactification, and 3D shuffling. With the capability of a phase-only Fourier mask to generate arbitrary shapes of the holographic microtraps, it was possible to place single atoms at arbitrary geometries of a few μm size and even continuously reconfigure them by conveying each atom. For this purpose, we loaded a series of computer-generated phase masks in the full frame rate of 60 Hz of the spatial light modulator, so the animation of phase mask transformed the holographic microtraps in real time, driving each atom along the assigned trajectory. Possible applications of this method of transformation of single atoms include preparation of scalable quantum platforms for quantum computation, quantum simulation, and quantum many-body physics.

  3. Three Dimensional Optic Tissue Culture and Process

    NASA Technical Reports Server (NTRS)

    OConnor, Kim C. (Inventor); Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); Aten, Laurie A. (Inventor); Francis, Karen M. (Inventor); Caldwell, Delmar R. (Inventor); Prewett, Tacey L. (Inventor); Fitzgerald, Wendy S. (Inventor)

    1999-01-01

    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioireactor at low shear conditions. The tissue forms as normal, functional tissue grows with tissue organization and extracellular matrix formation.

  4. Three dimensional optic tissue culture and process

    NASA Technical Reports Server (NTRS)

    Spaulding, Glenn F. (Inventor); Prewett, Tacey L. (Inventor); Goodwin, Thomas J. (Inventor); Francis, Karen M. (Inventor); Cardwell, Delmar R. (Inventor); Oconnor, Kim (Inventor); Fitzgerald, Wendy S. (Inventor); Aten, Laurie A. (Inventor)

    1994-01-01

    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioreactor at low shear conditions. The tissue forms normal, functional tissue organization and extracellular matrix.

  5. Multiparallel Three-Dimensional Optical Microscopy

    NASA Technical Reports Server (NTRS)

    Nguyen, Lam K.; Price, Jeffrey H.; Kellner, Albert L.; Bravo-Zanoquera, Miguel

    2010-01-01

    Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and mirrors that divide the output of the microscope into multiple channels. An imaging array of photodetectors in each channel is located at a different distance along the optical path from the microscope, corresponding to a focal plane at a different depth within the sample. The optical path leading to each photodetector array also includes lenses to compensate for the variation of magnification with distance so that the images ultimately formed on all the photodetector arrays are of the same magnification. The use of optical components common to multiple channels in a simple geometry makes it possible to obtain high light-transmission efficiency with an optically and mechanically simple assembly. In addition, because images can be read out simultaneously from all the photodetector arrays, the apparatus can support three-dimensional imaging at a high scanning rate.

  6. Three-Dimensional Optical Coherence Tomography

    NASA Technical Reports Server (NTRS)

    Gutin, Mikhail; Wang, Xu-Ming; Gutin, Olga

    2009-01-01

    Three-dimensional (3D) optical coherence tomography (OCT) is an advanced method of noninvasive infrared imaging of tissues in depth. Heretofore, commercial OCT systems for 3D imaging have been designed principally for external ophthalmological examination. As explained below, such systems have been based on a one-dimensional OCT principle, and in the operation of such a system, 3D imaging is accomplished partly by means of a combination of electronic scanning along the optical (Z) axis and mechanical scanning along the two axes (X and Y) orthogonal to the optical axis. In 3D OCT, 3D imaging involves a form of electronic scanning (without mechanical scanning) along all three axes. Consequently, the need for mechanical adjustment is minimal and the mechanism used to position the OCT probe can be correspondingly more compact. A 3D OCT system also includes a probe of improved design and utilizes advanced signal- processing techniques. Improvements in performance over prior OCT systems include finer resolution, greater speed, and greater depth of field.

  7. Thick, three-dimensional nanoporous density-graded materials formed by optical exposures of photopolymers with controlled levels of absorption

    NASA Astrophysics Data System (ADS)

    Nam, Yun-Suk; Jeon, Seokwoo; Jay-Lee Shir, Daniel; Hamza, Alex; Rogers, John A.

    2007-09-01

    Three-dimensional (3D) intensity distributions generated by light passing through conformal phase masks can be modulated by the absorption property of photosensitive materials. The intensity distributions have extremely long depth of focus, which is proportional to the size of the phase masks, and this enables one to pattern thick (˜100 μm), nanoporous structures with precise control of grade density. Various density-graded 3D structures that result from computational modeling are demonstrated. Results of x-ray radiograph and the controlled absorption coefficient prove the dominant mechanism of the generated graded density is absorption of the photosensitive materials. The graded-density structures can be applied to a chemical reservoir for controlled release of chemicals and laser target reservoirs useful to shape shockless wave compression.

  8. Three-dimensional winged nanocone optical antennas.

    PubMed

    Huttunen, Mikko J; Lindfors, Klas; Andriano, Domenico; Mäkitalo, Jouni; Bautista, Godofredo; Lippitz, Markus; Kauranen, Martti

    2014-06-15

    We introduce 3D optical antennas based on winged nanocones. The antennas support particle plasmon oscillations with current distributions that facilitate transformation of transverse far-field radiation to strong longitudinal local fields near the cone apices. We characterize the optical responses of the antennas by their extinction spectra and by second-harmonic generation microscopy with cylindrical vector beams. The results demonstrate a new 3D polarization-controllable optical antenna for applications in apertureless near-field microscopy, spectroscopy, and plasmonic sensing.

  9. Three-dimensional optical holography using a plasmonic metasurface

    PubMed Central

    Huang, Lingling; Chen, Xianzhong; Mühlenbernd, Holger; Zhang, Hao; Chen, Shumei; Bai, Benfeng; Tan, Qiaofeng; Jin, Guofan; Cheah, Kok-Wai; Qiu, Cheng-Wei; Li, Jensen; Zentgraf, Thomas; Zhang, Shuang

    2013-01-01

    Benefitting from the flexibility in engineering their optical response, metamaterials have been used to achieve control over the propagation of light to an unprecedented level, leading to highly unconventional and versatile optical functionalities compared with their natural counterparts. Recently, the emerging field of metasurfaces, which consist of a monolayer of photonic artificial atoms, has offered attractive functionalities for shaping wave fronts of light by introducing an abrupt interfacial phase discontinuity. Here we realize three-dimensional holography by using metasurfaces made of subwavelength metallic nanorods with spatially varying orientations. The phase discontinuity takes place when the helicity of incident circularly polarized light is reversed. As the phase can be continuously controlled in each subwavelength unit cell by the rod orientation, metasurfaces represent a new route towards high-resolution on-axis three-dimensional holograms with a wide field of view. In addition, the undesired effect of multiple diffraction orders usually accompanying holography is eliminated.

  10. Observation of three dimensional optical rogue waves through obstacles

    SciTech Connect

    Leonetti, Marco; Conti, Claudio

    2015-06-22

    We observe three-dimensional rogue waves in the speckle distribution of a spatially modulated optical beam. Light is transmitted beyond a partially reflecting obstacle generating optical rogue waves at a controlled position in the shadow of the barrier. When the barrier transmits only 0.07% of the input laser power, we observe the mostly localized event. These results demonstrate that an optimum amount of spatial non-homogeneity maximizes the probability of a gigantic event while the technique we exploit enables to control light behind a fully reflective wall.

  11. Observation of three dimensional optical rogue waves through obstacles

    NASA Astrophysics Data System (ADS)

    Leonetti, Marco; Conti, Claudio

    2015-06-01

    We observe three-dimensional rogue waves in the speckle distribution of a spatially modulated optical beam. Light is transmitted beyond a partially reflecting obstacle generating optical rogue waves at a controlled position in the shadow of the barrier. When the barrier transmits only 0.07% of the input laser power, we observe the mostly localized event. These results demonstrate that an optimum amount of spatial non-homogeneity maximizes the probability of a gigantic event while the technique we exploit enables to control light behind a fully reflective wall.

  12. A Three-Dimensional Optical Photonic Crystal

    SciTech Connect

    Fleming, J.G.; Lin, S.

    1998-12-17

    The search for a photonic crystal to confine optical waves in all three dimensions (3D) has proven to be a formidable task. It evolves from an early theoretical suggestion [1,2], a brief skepticism [3-5] and triumph in developing the mm-wave [6-8] and infrared 3D photonic crystals [9]. Yet, the challenge remains, as the ultimate goal for optoelectronic applications is to realize a 3D crystal at X=1.5 pm communication wavelengths. Operating at visible and near infrared wavelengths, X=1-2 pm, a photonic crystal may enhance the spontaneous emission rate [1, 10] and give rise to a semiconductor lasers with a zero lasing threshold[11, 12]. Another important application is optically switching, routing and interconnecting light [13,14] with an ultrafast transmission speed of terabits per second. A photonic crystal may also serve as a platform for integrating an all-optical circuitry with multiple photonic components, such as waveguides and switches, built on one chip [15]. In this Letter, we report on the successful fabrication of a working 3D crystal operating at optical L The minimum feature size of the 3D structure is 180 nanometers. The 3D crystal is free from defects over the entire 6-inch silicon wafer and has an absolute photonic band gap centered at A.-1.6 pm. Our data provides the first conclusive evidence for the existence of a full 3D photonic band gap in optical A. This development will pave the way to tinier, cheaper, more effective waveguides, optical switches and lasers.

  13. Alignment-free three-dimensional optical metamaterials.

    PubMed

    Zhao, Yang; Shi, Jinwei; Sun, Liuyang; Li, Xiaoqin; Alù, Andrea

    2014-03-01

    Three-dimensional optical metamaterials based on multilayers typically rely on critical vertical alignment to achieve the desired functionality. Here the conditions under which three-dimensional metamaterials with different functionalities may be realized without constraints on alignment are analyzed and demonstrated experimentally. This study demonstrates that the release of alignment constraints for multilayered metamaterials is allowed, while their anomalous interaction with light is preserved.

  14. High-speed optical beam alignment based on a motion control technique for three-dimensional microelectromechanical systems optical switch modules

    NASA Astrophysics Data System (ADS)

    Mizukami, Masato; Yamaguchi, Joji; Nemoto, Naru

    2011-07-01

    For optical axis alignment when light deflection control of a MEMS mirror is done at high speed, we propose a method based on identifying the quadratic surface shape. The method uses information about the optical power monitored when the mirror is inclined to a small angle. It is shown that the search for maximum optical power is possible by using this method. We also designed a control system with a band-stop filter for resonance frequency to decrease residual vibration generated when the mirror is moved at high speed. We confirm that the searchable level of optical power can be improved.

  15. Three-dimensional optical computed-tomography microscope

    NASA Astrophysics Data System (ADS)

    Chamgoulov, Ravil; Lane, Pierre; MacAulay, Calum

    2005-03-01

    We present our recent results on the development of three-dimensional (3-D) optical computed- tomography microscope. The instrument is a novel imaging device for the 3-D visualization and quantitative analysis of absorption-stained biological samples. The first instrument developed by our group at the BC Cancer Research Centre used a digital micromirror device (DMD) as a spatial light modulator to control the angles of illumination. This new embodiment employs an optical scanner instead of the DMD. The optical scanner is placed in the illumination path of the microscope system, conjugate to the field plane. The optical system includes also two high numerical aperture objective lenses, a sample stage, a light source, and a CCD camera. Projections are acquired by illuminating a specimen at a number of selected angles within the numerical aperture of the objective (0 < φ < 135°). A new reconstruction algorithm that employs both transform-based and iterative methods is developed to address the limited-angle reconstruction problem. A transform-based reconstruction is used as an initial starting point for the following iterative reconstruction. A feedback correction of the reconstructed image is made on each iteration step. The algorithm enables to incorporate previously known information about the object into the reconstruction process, and improves the reconstruction accuracy. Microscopic 3-D volume reconstructions of quantitatively absorption-stained cells have been generated. The system enables one to look at multiple optical levels of a specimen, and at more natural tissue architecture, including intact cells. Axial and lateral resolutions were measured to be better than 6 microns.

  16. Video-rate three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Laubscher, Markus; Ducros, Mathieu; Karamata, Boris; Lasser, Theo; Salathe, Rene

    2002-05-01

    Most current optical coherence tomography systems provide two-dimensional cross-sectional or en face images. Successive adjacent images have to be acquired to reconstruct three-dimensional objects, which can be time consuming. Here we demonstrate three-dimensional optical coherence tomography (3D OCT) at video rate. A 58 by 58 smart-pixel detector array was employed. A sample volume of 210x210x80 m3 (corresponding to 58x58x58 voxels) was imaged at 25 Hz. The longitudinal and transverse resolutions are 3 m and 9 m respectively. The sensitivity of the system was 76 dB. Video rate 3D OCT is illustrated by movies of a strand of hair undergoing fast thermal damage.

  17. Three-dimensional theory of the magneto-optical trap

    SciTech Connect

    Prudnikov, O. N. Taichenachev, A. V.; Yudin, V. I.

    2015-04-15

    The kinetics of atoms in a three-dimensional magneto-optical trap (MOT) is considered. A three-dimensional MOT model has been constructed for an atom with the optical transition J{sub g} = 0 → J{sub e} = 1 (J{sub g,} {sub e} is the total angular momentum in the ground and excited states) in the semiclassical approximation by taking into account the influence of the relative phases of light fields on the kinetics of atoms. We show that the influence of the relative phases can be neglected only in the limit of low light field intensities. Generally, the choice of relative phases can have a strong influence on the kinetics of atoms in a MOT.

  18. Ghost imaging for three-dimensional optical security

    SciTech Connect

    Chen, Wen Chen, Xudong

    2013-11-25

    Ghost imaging has become increasingly popular in quantum and optical application fields. Here, we report three-dimensional (3D) optical security using ghost imaging. The series of random phase-only masks are sparsified, which are further converted into particle-like distributions placed in 3D space. We show that either an optical or digital approach can be employed for the encoding. The results illustrate that a larger key space can be generated due to the application of 3D space compared with previous works.

  19. Three-dimensional optical trapping of partially silvered silica microparticles.

    PubMed

    Jordan, P; Cooper, J; McNay, G; Docherty, F T; Smith, W E; Sinclair, G; Padgett, M J

    2004-11-01

    We demonstrate three-dimensional trapping of micrometer-diameter silica particles, partially coated with silver, within conventional optical tweezers. Although metallic particles are usually repelled from the beam focus by the scattering force, we show that transparent spheres partially coated with silver can be trapped with efficiencies comparable with dielectric particles. The trapping characteristics of these particles are examined as a function of metallic coverage, and the application of these particles to surface-enhanced resonance Raman scattering is investigated.

  20. Three-dimensional Gradient Index Optics Fabricated in Diffusive Photopolymers

    NASA Astrophysics Data System (ADS)

    Ye, Chunfang

    This thesis demonstrates three-dimensional gradient index (GRIN) optics fabricated in two diffusive photopolymers. These polymer optical components have localized gradient index structures, which are self-developed in diffusive photopolymers by introducing localized illuminations. Based on the sizes of the formed index structures, the photopolymer optics studied in this thesis fall into two categories: GRIN lens based optics and waveguide based optics. GRIN lenses and lens arrays with parabolic index profiles are created through Gaussian beam exposure, while GRIN lenses with arbitrary index profiles are created through a dual-axis galvo scanning system. Waveguide based optics, which include uniform waveguides, waveguide tapers, waveguides through thin optics and 900 sharp waveguide bends, are fabricated through direct-write lithography. Several quantitative characterization methods for the fabricated polymer optics are described. The index profiles of the GRIN lens based optics are quantitatively measured by a modified scanning transmission phase microscope and a Shack-Hartmann wavefront sensor. Three-dimensional mode profile characterization of the polymer waveguides is carried out through a novel polymer sample preparation procedure and an active mode imaging system. A single mode performance is confirmed for the fabricated waveguides. A loss measurement for the waveguides is also accomplished. An index formation model is developed for a diffusive polymer developed by Dr. McLeod's group, which provides a fundamental guidance for fabricating custom-design index structures in the polymer. A hybrid GRIN axicon lens is fabricated to significantly extend the depth of focus in an endoscopy OCT application. Potential applications of the fabricated polymer optics include hybrid integrated optical circuits. The diffusive photopolymer with self-development characteristics provides a platform to integrate various optoelectronic subcomponents in integrated optical circuits.

  1. Ordinary polarization singularities in three-dimensional optical fields.

    PubMed

    Freund, Isaac

    2012-06-15

    In generic three-dimensional optical fields the canonical point polarization singularities are points of circular polarization, C points on C lines, and points of linear polarization, L points on L lines. These special points are surrounded by a sea of ordinary points. In planes oriented normal to the principle axes of the polarization ellipse at the point, every ordinary point is also a singularity, here an ordinary polarization singularity, or O point. Interactions between O points, between O points and C points, and between O points and L points are described that highlight the fact that a consistent description of optical fields containing C and L lines must include O points.

  2. Three-dimensional multifunctional optical coherence tomography for skin imaging

    NASA Astrophysics Data System (ADS)

    Li, En; Makita, Shuichi; Hong, Young-Joo; Kasaragod, Deepa; Sasaoka, Tomoko; Yamanari, Masahiro; Sugiyama, Satoshi; Yasuno, Yoshiaki

    2016-02-01

    Optical coherence tomography (OCT) visualizes cross-sectional microstructures of biological tissues. Recent developments of multifunctional OCT (MF-OCT) provides multiple optical contrasts which can reveal currently unknown tissue properties. In this contribution we demonstrate multifunctional OCT specially designed for dermatological investigation. And by utilizing it to measure four different body parts of in vivo human skin, three-dimensional scattering OCT, OCT angiography, polarization uniformity tomography, and local birefringence tomography images were obtained by a single scan. They respectively contrast the structure and morphology, vasculature, melanin content and collagen traits of the tissue.

  3. Three-dimensional optical encryption based on ptychography

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Li, Tuo; Wang, Yali; Qiao, Liang; Yang, Xiubo; Shi, Yishi

    2015-10-01

    We propose a novel optical encryption system for three-dimension imaging combined with three-dimension Ptychography. Employing the proposed cryptosystem, a 3D object can be encrypted and decrypted successfully. Compared with the conventional three-dimensional cryptosystem, not only encrypting the pure amplitude 3D object is available, but also the encryption of complex amplitude 3D object is achievable. Considering that the probes overlapping with each other is the crucial factor in ptychography, their complex-amplitude functions can serve as a kind of secret keys that lead to the enlarged key space and the enhanced system security. Varies of simulation results demonstrate that the feasibility and robust of the cryptosystem. Furthermore, the proposed system could also be used for other potential applications, such as three-dimensional information hiding and multiple images encryption.

  4. Optical Security Card by Three-dimensional Random Phase Distribution

    NASA Astrophysics Data System (ADS)

    Matoba, Osamu; Nitta, Kouichi

    2007-10-01

    An optical security card based on a three-dimensional (3D) phase object is presented. This card enables us to develop a personal authentification system and secure data storage in a highly scattering medium. The authentification is implemented by the correlation between a speckle pattern of the 3D phase object and stored speckle patterns. For secure data storage, absorption distribution is involved in a scattering volume medium. Appropriate user can only reconstruct the absorption distribution by solving inverse problem. Experimental and numerical results are presented to show the effectiveness of the proposed system.

  5. Tunable optical anisotropy in three-dimensional photonic crystals

    SciTech Connect

    Che Ming; Li Zhiyuan; Liu Rongjuan

    2007-08-15

    Artificial optical birefringence can be realized in three-dimensional photonic crystals with a uniaxial structural symmetry: e.g., woodpile photonic crystals with a tetragonal lattice structure in the long-wavelength limit. The ordinary and extraordinary indices of refraction are determined from calculation of the reflection coefficient for a plane wave incident on the surface of a semi-infinite photonic crystal at different angles. We find that the anisotropy can be widely tuned by simply changing the width and thickness of the dielectric rod. A large relative negative anisotropy over 33% is found. A transition from positive anisotropy to negative anisotropy can be readily achieved. At certain parameters, a structurally anisotropic nanostructure can behave like an optically isotropic medium. Our study opens a window to use artificial nanostructures to create an arbitrary optical anisotropy that is not possible in natural crystals.

  6. Photopolymer-based three-dimensional optical waveguide devices

    NASA Astrophysics Data System (ADS)

    Kagami, M.; Yamashita, T.; Yonemura, M.; Kawasaki, A.; Watanabe, O.; Tomiki, M.

    2012-02-01

    Photopolymer based three-dimensional (3D) waveguide devices are very attractive in low-cost optical system integration. Especially, Light-Induced Self-Written (LISW) technology is suitable for this application, and the technology enables low-loss 3D optical circuitry formation from an optical fiber tip which soaked in photopolymer solution by employing its photo-polymerization due to own irradiation from the fiber tip. This technology is expected drastic mounting cost reduction in fields of micro-optic and hybrid integration devices assembly. The principle of the LISW optical waveguides is self-trapping effect of the irradiation flux into the self-organized waveguide, where, used wavelength can be chosen to fit photopolymer's reactivity from visible to infrared. Furthermore, this effect also makes possible grating formation and "optical solder" interconnection. Actually fabricated self-written grating shows well defined deep periodic index contrast and excellent optical property for the wavelength selectivity. And the "optical solder" interconnection realizes a passive optical interconnection between two faceted fibers or devices by the LISW waveguide even if there is a certain amount of gap and a small degree of misalignment exist. The LISW waveguides grow towards each other from both sides to a central point where the opposing beams overlap and are then combined into one waveguide. This distinctive effect is confirmed in all kind optical fibers, such as from a singlemode to 1-mm-corediameter multimode optical fiber. For example of complicated WDM optical transceiver module, mounted a branchedwaveguide and filter elements, effectiveness of LISW technology is outstanding. In assembling and packaging process, neither dicing nor polishing is needed. In this paper, we introduce LISW technology principles and potential application to integrated WDM optical transceiver devices for both of singlemode and multimode system developed in our research group.

  7. Three dimensional imaging detector employing wavelength-shifting optical fibers

    DOEpatents

    Worstell, W.A.

    1997-02-04

    A novel detector element structure and method for its use is provided. In a preferred embodiment, one or more inorganic scintillating crystals are coupled through wavelength shifting optical fibers (WLSFs) to position sensitive photomultipliers (PS-PMTs). The superior detector configuration in accordance with this invention is designed for an array of applications in high spatial resolution gamma ray sensing with particular application to SPECT, PET and PVI imaging systems. The design provides better position resolution than prior art devices at a lower total cost. By employing wavelength shifting fibers (WLSFs), the sensor configuration of this invention can operate with a significant reduction in the number of photomultipliers and electronics channels, while potentially improving the resolution of the system by allowing three dimensional reconstruction of energy deposition positions. 11 figs.

  8. Three-dimensional multiway power dividers based on transformation optics.

    PubMed

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-01-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers. PMID:27091541

  9. Three dimensional imaging detector employing wavelength-shifting optical fibers

    DOEpatents

    Worstell, William A.

    1997-01-01

    A novel detector element structure and method for its use is provided. In a preferred embodiment, one or more inorganic scintillating crystals are coupled through wavelength shifting optical fibers (WLSFs) to position sensitive photomultipliers (PS-PMTs). The superior detector configuration in accordance with this invention is designed for an array of applications in high spatial resolution gamma ray sensing with particular application to SPECT, PET and PVI imaging systems. The design provides better position resolution than prior art devices at a lower total cost. By employing wavelength shifting fibers (WLSFs), the sensor configuration of this invention can operate with a significant reduction in the number of photomultipliers and electronics channels, while potentially improving the resolution of the system by allowing three dimensional reconstruction of energy deposition positions.

  10. Three-dimensional multiway power dividers based on transformation optics

    PubMed Central

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-01-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers. PMID:27091541

  11. Three-dimensional optical vortex and necklace solitons in highly nonlocal nonlinear media

    NASA Astrophysics Data System (ADS)

    Zhong, Wei-Ping; Belić, Milivoj

    2009-02-01

    We demonstrate the existence of localized optical vortex and necklace solitons in three-dimensional (3D) highly nonlocal nonlinear media, both analytically and numerically. The 3D solitons are constructed with the help of Kummer’s functions in spherical coordinates and their unique properties are discussed. The procedure we follow offers ways for generation, control, and manipulation of spatial solitons.

  12. Electroencephalographic (EEG) control of three-dimensional movement

    NASA Astrophysics Data System (ADS)

    McFarland, Dennis J.; Sarnacki, William A.; Wolpaw, Jonathan R.

    2010-06-01

    Brain-computer interfaces (BCIs) can use brain signals from the scalp (EEG), the cortical surface (ECoG), or within the cortex to restore movement control to people who are paralyzed. Like muscle-based skills, BCIs' use requires activity-dependent adaptations in the brain that maintain stable relationships between the person's intent and the signals that convey it. This study shows that humans can learn over a series of training sessions to use EEG for three-dimensional control. The responsible EEG features are focused topographically on the scalp and spectrally in specific frequency bands. People acquire simultaneous control of three independent signals (one for each dimension) and reach targets in a virtual three-dimensional space. Such BCI control in humans has not been reported previously. The results suggest that with further development noninvasive EEG-based BCIs might control the complex movements of robotic arms or neuroprostheses.

  13. Three dimensional optical coherence tomography imaging: advantages and advances.

    PubMed

    Gabriele, Michelle L; Wollstein, Gadi; Ishikawa, Hiroshi; Xu, Juan; Kim, Jongsick; Kagemann, Larry; Folio, Lindsey S; Schuman, Joel S

    2010-11-01

    Three dimensional (3D) ophthalmic imaging using optical coherence tomography (OCT) has revolutionized assessment of the eye, the retina in particular. Recent technological improvements have made the acquisition of 3D-OCT datasets feasible. However, while volumetric data can improve disease diagnosis and follow-up, novel image analysis techniques are now necessary in order to process the dense 3D-OCT dataset. Fundamental software improvements include methods for correcting subject eye motion, segmenting structures or volumes of interest, extracting relevant data post hoc and signal averaging to improve delineation of retinal layers. In addition, innovative methods for image display, such as C-mode sectioning, provide a unique viewing perspective and may improve interpretation of OCT images of pathologic structures. While all of these methods are being developed, most remain in an immature state. This review describes the current status of 3D-OCT scanning and interpretation, and discusses the need for standardization of clinical protocols as well as the potential benefits of 3D-OCT scanning that could come when software methods for fully exploiting these rich datasets are available clinically. The implications of new image analysis approaches include improved reproducibility of measurements garnered from 3D-OCT, which may then help improve disease discrimination and progression detection. In addition, 3D-OCT offers the potential for preoperative surgical planning and intraoperative surgical guidance.

  14. Three-dimensional control of Tetrahymena pyriformis using artificial magnetotaxis

    NASA Astrophysics Data System (ADS)

    Hyung Kim, Dal; Seung Soo Kim, Paul; Agung Julius, Anak; Jun Kim, Min

    2012-01-01

    We demonstrate three-dimensional control with the eukaryotic cell Tetrahymena pyriformis (T. pyriformis) using two sets of Helmholtz coils for xy-plane motion and a single electromagnet for z-direction motion. T. pyriformis is modified to have artificial magnetotaxis with internalized magnetite. To track the cell's z-axis position, intensity profiles of non-motile cells at varying distances from the focal plane are used. During vertical motion along the z-axis, the intensity difference is used to determine the position of the cell. The three-dimensional control of the live microorganism T. pyriformis as a cellular robot shows great potential for practical applications in microscale tasks, such as target transport and cell therapy.

  15. Three-dimensional acousto-optic spectrum analysis

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Metscher, Brian; Lesh, James R.

    1990-01-01

    A three-dimensional acoustooptic spectrum analyzer with subhertz resolution is demonstrated experimentally. The first and second dimensions are the two spatial dimensions of the output detector array, and the third dimension is time as sampled by the detector array frame rate. A superfine resolution of 0.12 Hz has been achieved.

  16. Optical properties of three-dimensional arrays of semiconductor nanocrystals

    NASA Astrophysics Data System (ADS)

    Kim, Bosang

    The major part of this thesis is devoted to interdot interactions in CdSe nanocrystal arrays at elevated pressure. Three-dimensional arrays of organically passivated CdSe nanocrystals were investigated under hydrostatic pressure using photoluminescence (PL) and absorption spectroscopies. Interdot separations were varied coarsely by varying the organic ligand on the nanocrystal and finely by applying hydrostatic pressure. The PL and absorption spectra of solutions and arrays of CdSe nanocrystals capped by tri-n-octylphosphine oxide (TOPO) or tri-n-butylphosphine oxide (TBPO) are the same up to 60 kbar. In contrast, there is a distinct difference between the pressure dependence of CdSe/pyridine dots in solution and arrays. This different dependence can be attributed to several factors, including possible carrier coupling between neighboring nanoparticles through the organic ligands capping the respective particles that would lead to a decrease in carrier confinement energy. The kinetics of solvent and organic ligand of CdSe nanocrystal arrays during the assembly were quantitatively investigated. Attenuated total reflection is shown to be a quantitative real-time probe of several important features of nanocrystal self-assembly by following the infrared absorption of the solvent and the organic ligands that passivate the nanocrystal surface. During the self-assembly of a 250 monolayer array of CdSe nanocrystals capped by pyridine, the pyridine solvent molecules evaporate in ˜30--40 min and the pyridine-capping molecules leave the array very slowly, apparently limited by diffusion, with ˜30 +/- 8% remaining after three days. The method of spin-assisted self-assembly was used to produce sub-micron thick films of CdSe nanocrystals. The uniformity was investigated with various spin rate and solvents; the films made from a hexane/octane mixture at a spin rate of 100 RPM with intermittent pauses resulted in the least fluctuations in film thickness. Using optical microscopy

  17. Controlling Random Lasing with Three-Dimensional Plasmonic Nanorod Metamaterials.

    PubMed

    Wang, Zhuoxian; Meng, Xiangeng; Choi, Seung Ho; Knitter, Sebastian; Kim, Young L; Cao, Hui; Shalaev, Vladimir M; Boltasseva, Alexandra

    2016-04-13

    Plasmonics has brought revolutionary advances to laser science by enabling deeply subwavelength nanolasers through surface plasmon amplification. However, the impact of plasmonics on other promising laser systems has so far remained elusive. Here, we present a class of random lasers enabled by three-dimensional plasmonic nanorod metamaterials. While dense metallic nanostructures are usually detrimental to laser performance due to absorption losses, here the lasing threshold keeps decreasing as the volume fraction of metal is increased up to ∼0.07. This is ∼460 times higher than the optimal volume fraction reported thus far. The laser supports spatially confined lasing modes and allows for efficient modulation of spectral profiles by simply tuning the polarization of the pump light. Full-field speckle-free imaging at micron-scales has been achieved by using plasmonic random lasers as the illumination sources. Our findings show that plasmonic metamaterials hold potential to enable intriguing coherent optical sources.

  18. Controlling Random Lasing with Three-Dimensional Plasmonic Nanorod Metamaterials.

    PubMed

    Wang, Zhuoxian; Meng, Xiangeng; Choi, Seung Ho; Knitter, Sebastian; Kim, Young L; Cao, Hui; Shalaev, Vladimir M; Boltasseva, Alexandra

    2016-04-13

    Plasmonics has brought revolutionary advances to laser science by enabling deeply subwavelength nanolasers through surface plasmon amplification. However, the impact of plasmonics on other promising laser systems has so far remained elusive. Here, we present a class of random lasers enabled by three-dimensional plasmonic nanorod metamaterials. While dense metallic nanostructures are usually detrimental to laser performance due to absorption losses, here the lasing threshold keeps decreasing as the volume fraction of metal is increased up to ∼0.07. This is ∼460 times higher than the optimal volume fraction reported thus far. The laser supports spatially confined lasing modes and allows for efficient modulation of spectral profiles by simply tuning the polarization of the pump light. Full-field speckle-free imaging at micron-scales has been achieved by using plasmonic random lasers as the illumination sources. Our findings show that plasmonic metamaterials hold potential to enable intriguing coherent optical sources. PMID:27023052

  19. Three dimensional laser microfabrication in diamond using a dual adaptive optics system.

    PubMed

    Simmonds, Richard D; Salter, Patrick S; Jesacher, Alexander; Booth, Martin J

    2011-11-21

    Femtosecond laser fabrication of controlled three dimensional structures deep in the bulk of diamond is facilitated by a dual adaptive optics system. A deformable mirror is used in parallel with a liquid crystal spatial light modulator to compensate the extreme aberrations caused by the refractive index mismatch between the diamond and the objective immersion medium. It is shown that aberration compensation is essential for the generation of controlled micron-scale features at depths greater than 200 μm, and the dual adaptive optics approach demonstrates increased fabrication efficiency relative to experiments using a single adaptive element. PMID:22109438

  20. Three-dimensional solidification and melting using magnetic field control

    NASA Technical Reports Server (NTRS)

    Dulikravich, George S.; Ahuja, Vineet

    1993-01-01

    A new two-fluid mathematical model for fully three dimensional steady solidification under the influence of an arbitrary acceleration vector and with or without an arbitrary externally applied steady magnetic field have been formulated and integrated numerically. The model includes Joule heating and allows for separate temperature dependent physical properties within the melt and the solid. Latent heat of phase change during melting/solidification was incorporated using an enthalpy method. Mushy region was automatically captured by varying viscosity orders of magnitude between liquidus and solidus temperature. Computational results were obtained for silicon melt solidification in a parallelepiped container cooled from above and from a side. The results confirm that the magnetic field has a profound influence on the solidifying melt flow field thus changing convective heat transfer through the boundaries and the amount and shape of the solid accrued. This suggests that development of a quick-response algorithm for active control of three dimensional solidification is feasible since it would require low strength magnetic fields.

  1. Three-dimensional confocal optical imagery of precambrian microscopic organisms.

    PubMed

    Schopf, J William; Tripathi, Abhishek B; Kudryavtsev, Anatoliy B

    2006-02-01

    A major difficulty that has long hindered studies of organic-walled Precambrian microbes in petrographic thin sections is the accurate documentation of their three-dimensional morphology. To address this need, we here demonstrate the use of confocal laser scanning microscopy. This technique, both non-intrusive and non-destructive, can provide data by which to objectively characterize, in situ and at submicron-scale resolution, the cellular and organismal morphology of permineralized (petrified) microorganisms. Application of this technique can provide information in three dimensions about the morphology, taphonomy, and fidelity of preservation of such fossils at a spatial resolution unavailable by any other means.

  2. Three-dimensional angular domain optical projection tomography

    NASA Astrophysics Data System (ADS)

    Ng, Eldon; Vasefi, Fartash; Roumeliotis, Michael; Kaminska, Bozena; Carson, Jeffrey J. L.

    2011-03-01

    Angular Domain Imaging (ADI) has been previously demonstrated to generate projection images of attenuating targets embedded within a turbid medium. The imaging system employs a silicon micro-tunnel array positioned between the sample and the detection system to reject scattered photons that have deviated from the initial propagation direction and to select for ballistic and quasi-ballistic photons that have retained their forward trajectory. Two dimensional tomographic images can be reconstructed from ADI projections collected at a multitude of angles. The objective of this work was to extend the system to three dimensions by collecting several tomographic images and stacking the reconstructed slices to generate a three dimensional volume representative of the imaging target. A diode laser (808nm, CW) with a beam expander was used to illuminate the sample cuvette. An Angular Filter Array (AFA) of 80 μm × 80 μm square-shaped tunnels 2 cm in length was used to select for image forming quasi-ballistic photons. Images were detected with a linear CCD. Our approach was to use a SCARA robot to rotate and translate the sample to collect sufficient projections to reconstruct a three dimensional volume. A custom designed 3D target consisting of 4 truncated cones was imaged and reconstructed with filtered backprojection and iterative methods. A 0.5 mm graphite rod was used to collect the forward model, while a truncated pseudoinverse was used to approximate the backward model for the iterative algorithm.

  3. Three-dimensional control of crystal growth using magnetic fields

    NASA Astrophysics Data System (ADS)

    Dulikravich, George S.; Ahuja, Vineet; Lee, Seungsoo

    1993-07-01

    Two coupled systems of partial differential equations governing three-dimensional laminar viscous flow undergoing solidification or melting under the influence of arbitrarily oriented externally applied magnetic fields have been formulated. The model accounts for arbitrary temperature dependence of physical properties including latent heat release, effects of Joule heating, magnetic field forces, and mushy region existence. On the basis of this model a numerical algorithm has been developed and implemented using central differencing on a curvilinear boundary-conforming grid and Runge-Kutta explicit time-stepping. The numerical results clearly demonstrate possibilities for active and practically instantaneous control of melt/solid interface shape, the solidification/melting front propagation speed, and the amount and location of solid accrued.

  4. Laser electro-optic system for rapid three-dimensional /3-D/ topographic mapping of surfaces

    NASA Technical Reports Server (NTRS)

    Altschuler, M. D.; Altschuler, B. R.; Taboada, J.

    1981-01-01

    It is pointed out that the generic utility of a robot in a factory/assembly environment could be substantially enhanced by providing a vision capability to the robot. A standard videocamera for robot vision provides a two-dimensional image which contains insufficient information for a detailed three-dimensional reconstruction of an object. Approaches which supply the additional information needed for the three-dimensional mapping of objects with complex surface shapes are briefly considered and a description is presented of a laser-based system which can provide three-dimensional vision to a robot. The system consists of a laser beam array generator, an optical image recorder, and software for controlling the required operations. The projection of a laser beam array onto a surface produces a dot pattern image which is viewed from one or more suitable perspectives. Attention is given to the mathematical method employed, the space coding technique, the approaches used for obtaining the transformation parameters, the optics for laser beam array generation, the hardware for beam array coding, and aspects of image acquisition.

  5. Measuring three-dimensional interaction potentials using optical interference.

    PubMed

    Mojarad, Nassir; Sandoghdar, Vahid; Krishnan, Madhavi

    2013-04-22

    We describe the application of three-dimensional (3D) scattering interferometric (iSCAT) imaging to the measurement of spatial interaction potentials for nano-objects in solution. We study electrostatically trapped gold particles in a nanofluidic device and present details on axial particle localization in the presence of a strongly reflecting interface. Our results demonstrate high-speed (~kHz) particle tracking with subnanometer localization precision in the axial and average 2.5 nm in the lateral dimension. A comparison of the measured levitation heights of trapped particles with the calculated values for traps of various geometries reveals good agreement. Our work demonstrates that iSCAT imaging delivers label-free, high-speed and accurate 3D tracking of nano-objects conducive to probing weak and long-range interaction potentials in solution. PMID:23609648

  6. Quantifying three-dimensional optic axis using polarization-sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Liu, Chao J.; Black, Adam J.; Wang, Hui; Akkin, Taner

    2016-07-01

    The optic axis of birefringent samples indicates the direction of optical anisotropy, which should be described in three-dimensional (3-D) space. We present a method to quantify the complete 3-D optic axis orientation calculated from in-plane optic axis measurements from a polarization-sensitive optical coherence tomography system. The in-plane axis orientations with different illumination angles allow the calculation of the necessary polar angle. The method then provides the information to produce the actual birefringence. The method and results from a biological sample are presented.

  7. Assembling Three-Dimensional Optical Stereo-Nanocircuits

    NASA Astrophysics Data System (ADS)

    Shi, Jinwei; Elias, Sarah; Monticone, Francesco; Wu, Yanwen; Ratchford, Daniel; Li, Xiaoqin; Alu, Andrea

    2014-03-01

    The development level of integration of photonic devices is lagging behind compared with microelectronics, due to diffraction limit and the difficulty of realizing basic functionalities with lumped photonic circuit elements at the nanoscale and achieving versatile operations by combining these elements in large circuits. Here we demonstrate the design, assembly and characterization of various 3D photonic nanocircuits with increasing complexity by accurately positioning a number of metallic and dielectric nanoparticles (NPs) in a reconfigurable way with atomic force microscope (AFM) manipulation, in analogy to what an electrical engineer does when putting together an electronic circuit. The NP clusters are shown to produce the designed spectral response, qualitatively predicted by simple circuit rules, with fixed optical lumped impedance value of each NP for different nanocircuit configurations. Additionally, such nanophotonic circuits exhibit stereo-functionality, i.e., a response that can be controlled by the polarization of impinging light. Our work represents an important step toward transplanting and extending the powerful design tools of electronic circuits to nanophotonic systems.

  8. Three-Dimensional Displacement Measurement Using Diffractive Optic Interferometry

    NASA Technical Reports Server (NTRS)

    Gilbert, John A.; Cole, Helen J.; Shepherd, Robert L.; Ashley Paul R.

    1999-01-01

    This paper introduces a powerful new optical method which utilizes diffractive optic interferometry (DOI) to measure both in-plane and out-of-plane displacement with variable sensitivity using the same optical system. Sensitivity is varied by utilizing various combinations of the different wavefronts produced by a conjugate pair of binary Optical elements; a transmission grating is used to produce several illumination beams while a reflective grating replicated on the surface of a specimen, provides the reference for the undeformed state. A derivation of the equations which govern the method is included along with a discussion Of the experimental tests conducted to verify the theory. Overall, the results are excellent, with experimental data agreeing to within a few percent of the theoretical predictions.

  9. Three-Dimensional Acousto-Optical Spectrum Analyzer

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Lesh, James R.

    1991-01-01

    Experimental acousto-optical Bragg-cell spectrum analyzer achieves subhertz frequency resolution. System represents extension to three dimensions of two-dimensional spectrum-analyzer concept described in, "Two-Dimensional Acousto-Optical Spectrum Analyzer" (NPO-18092). First and second dimensions two spatial dimensions of charge-coupled-device (CCD) imaging array. Third dimension time, as sampled at frame rate of CCD array.

  10. Rewritable three-dimensional holographic data storage via optical forces

    NASA Astrophysics Data System (ADS)

    Yetisen, Ali K.; Montelongo, Yunuen; Butt, Haider

    2016-08-01

    The development of nanostructures that can be reversibly arranged and assembled into 3D patterns may enable optical tunability. However, current dynamic recording materials such as photorefractive polymers cannot be used to store information permanently while also retaining configurability. Here, we describe the synthesis and optimization of a silver nanoparticle doped poly(2-hydroxyethyl methacrylate-co-methacrylic acid) recording medium for reversibly recording 3D holograms. We theoretically and experimentally demonstrate organizing nanoparticles into 3D assemblies in the recording medium using optical forces produced by the gradients of standing waves. The nanoparticles in the recording medium are organized by multiple nanosecond laser pulses to produce reconfigurable slanted multilayer structures. We demonstrate the capability of producing rewritable optical elements such as multilayer Bragg diffraction gratings, 1D photonic crystals, and 3D multiplexed optical gratings. We also show that 3D virtual holograms can be reversibly recorded. This recording strategy may have applications in reconfigurable optical elements, data storage devices, and dynamic holographic displays.

  11. Three-dimensional photonic metamaterials at optical frequencies

    NASA Astrophysics Data System (ADS)

    Liu, Na; Guo, Hongcang; Fu, Liwei; Kaiser, Stefan; Schweizer, Heinz; Giessen, Harald

    2008-01-01

    Metamaterials are artificially structured media with unit cells much smaller than the wavelength of light. They have proved to possess novel electromagnetic properties, such as negative magnetic permeability and negative refractive index. This enables applications such as negative refraction, superlensing and invisibility cloaking. Although the physical properties can already be demonstrated in two-dimensional (2D) metamaterials, the practical applications require 3D bulk-like structures. This prerequisite has been achieved in the gigahertz range for microwave applications owing to the ease of fabrication by simply stacking printed circuit boards. In the optical domain, such an elegant method has been the missing building block towards the realization of 3D metamaterials. Here, we present a general method to manufacture 3D optical (infrared) metamaterials using a layer-by-layer technique. Specifically, we introduce a fabrication process involving planarization, lateral alignment and stacking. We demonstrate stacked metamaterials, investigate the interaction between adjacent stacked layers and analyse the optical properties of stacked metamaterials with respect to an increasing number of layers.

  12. Optical magnetoplasmons in rhombohedral graphite with a three-dimensional Dirac cone structure

    NASA Astrophysics Data System (ADS)

    Ho, Ching-Hong; Chang, Cheng-Peng; Lin, Ming-Fa

    2015-04-01

    Rhombohedral graphite has a three-dimensional Dirac cone structure, differing only perturbatively from the bulk stack of independent graphene layers, so that the three-dimensional integer quantum Hall effect can be well exhibited in this system. In this paper, optical magnetoplasmons are obtained by using the random phase approximation. Such collective excitations do not exist in monolayer graphene but are shown to originate from Landau level mixing due to interlayer Coulomb interaction in the quantum Hall effect regime. The three-dimensional character of rhombohedral graphite is thus demonstrated. The results should be realized in response to a longitudinal external electric field or an incident infrared electromagnetic wave.

  13. Non-contact optical three dimensional liner metrology.

    SciTech Connect

    Sebring, R. J.; Anderson, W. E.; Bartos, J. J.; Garcia, F.; Randolph, B.; Salazar, M. A.; Edwards, J. M.

    2001-01-01

    We optically captured the 'as-built' liner geometry of NTLX (near term liner experiments) for Shiva Star using ultra-precision ranging lasers. We subsequently verified the resulting digitized geometry against the 3D CAD model of the part. The results confirmed that the Liner contours are within designed tolerances but revealed subtle fabrication artifacts that would typically go undetected. These features included centimeters long waviness and saddle and bulge regions of 1 micron or less in magnitude. The laser technology typically provided 10 micron spatial resolution with {+-}12 nanometer ranging precision. Atlas liners in the future may have to be diamond turned and will have the centimeter wavelength and 100 angstrom amplitude requirements. The advantages of using laser technology are (1) it avoids surface damage that may occur with conventional contact probes and (2) dramatically improves spatial resolution over CMM, capacitance and inductance type probes. Our work is the result of a perceived future need to develop precision, non-contact, liner inspection techniques to verify geometry, characterize machining artifacts and map wall thickness on delicate diamond turned surfaces. Capturing 'as-built' geometry in a non-contact way coupled with part-to-CAD verification software tools creates a new metrology competency for MST-7.

  14. Three dimensional optical twisters-driven helically stacked multi-layered microrotors

    NASA Astrophysics Data System (ADS)

    Xavier, Jolly; Dasgupta, Raktim; Ahlawat, Sunita; Joseph, Joby; Kumar Gupta, Pradeep

    2012-03-01

    We demonstrate tunable helically stacked multi-layered microrotors realized in vortex-embedded three dimensional (3D) optical twister patterns. Intensity-tunable annular irradiance profiles with higher order vortex are generated as well as simultaneously unfolded by phase-engineered multiple plane wave interference. In the individually tunable 3D helical bright arms of these unfolded vortex structures, 2 μm silica beads are optically trapped as spiraling multilayered handles of multi-armed microrotors. Further, multiple rows of such microrotors are parallelly actuated with controllable sense of rotation. We also present our observation on helical 3D stacking of micro-particles in these longitudinally gyrating multi-armed rotor traps.

  15. Three-Dimensional Optical Trapping of a Plasmonic Nanoparticle using Low Numerical Aperture Optical Tweezers

    PubMed Central

    Brzobohatý, Oto; Šiler, Martin; Trojek, Jan; Chvátal, Lukáš; Karásek, Vítězslav; Paták, Aleš; Pokorná, Zuzana; Mika, Filip; Zemánek, Pavel

    2015-01-01

    It was previously believed that larger metal nanoparticles behave as tiny mirrors that are pushed by the light beam radiative force along the direction of beam propagation, without a chance to be confined. However, several groups have recently reported successful optical trapping of gold and silver particles as large as 250 nm. We offer a possible explanation based on the fact that metal nanoparticles naturally occur in various non-spherical shapes and their optical properties differ significantly due to changes in localized plasmon excitation. We demonstrate experimentally and support theoretically three-dimensional confinement of large gold nanoparticles in an optical trap based on very low numerical aperture optics. We showed theoretically that the unique properties of gold nanoprisms allow an increase of trapping force by an order of magnitude at certain aspect ratios. These results pave the way to spatial manipulation of plasmonic nanoparticles using an optical fibre, with interesting applications in biology and medicine. PMID:25630432

  16. Three-dimensional positioning and control of colloidal objects utilizing engineered liquid crystalline defect networks.

    PubMed

    Yoshida, H; Asakura, K; Fukuda, J; Ozaki, M

    2015-01-01

    Topological defects in liquid crystals not only affect the optical and rheological properties of the host, but can also act as scaffolds in which to trap nano or micro-sized colloidal objects. The creation of complex defect shapes, however, often involves confining the liquid crystals in curved geometries or adds complex-shaped colloidal objects, which are unsuitable for device applications. Using topologically patterned substrates, here we demonstrate the controlled generation of three-dimensional defect lines with non-trivial shapes and even chirality, in a flat slab of nematic liquid crystal. By using the defect lines as templates and the electric response of the liquid crystals, colloidal superstructures are constructed, which can be reversibly reconfigured at a voltage as low as 1.3 V. Three-dimensional engineering of the defect shapes in liquid crystals is potentially useful in the fabrication of self-healing composites and in stabilizing artificial frustrated phases.

  17. Three-dimensional positioning and control of colloidal objects utilizing engineered liquid crystalline defect networks.

    PubMed

    Yoshida, H; Asakura, K; Fukuda, J; Ozaki, M

    2015-01-01

    Topological defects in liquid crystals not only affect the optical and rheological properties of the host, but can also act as scaffolds in which to trap nano or micro-sized colloidal objects. The creation of complex defect shapes, however, often involves confining the liquid crystals in curved geometries or adds complex-shaped colloidal objects, which are unsuitable for device applications. Using topologically patterned substrates, here we demonstrate the controlled generation of three-dimensional defect lines with non-trivial shapes and even chirality, in a flat slab of nematic liquid crystal. By using the defect lines as templates and the electric response of the liquid crystals, colloidal superstructures are constructed, which can be reversibly reconfigured at a voltage as low as 1.3 V. Three-dimensional engineering of the defect shapes in liquid crystals is potentially useful in the fabrication of self-healing composites and in stabilizing artificial frustrated phases. PMID:25994837

  18. Three-dimensional positioning and control of colloidal objects utilizing engineered liquid crystalline defect networks

    PubMed Central

    Yoshida, H.; Asakura, K.; Fukuda, J.; Ozaki, M.

    2015-01-01

    Topological defects in liquid crystals not only affect the optical and rheological properties of the host, but can also act as scaffolds in which to trap nano or micro-sized colloidal objects. The creation of complex defect shapes, however, often involves confining the liquid crystals in curved geometries or adds complex-shaped colloidal objects, which are unsuitable for device applications. Using topologically patterned substrates, here we demonstrate the controlled generation of three-dimensional defect lines with non-trivial shapes and even chirality, in a flat slab of nematic liquid crystal. By using the defect lines as templates and the electric response of the liquid crystals, colloidal superstructures are constructed, which can be reversibly reconfigured at a voltage as low as 1.3 V. Three-dimensional engineering of the defect shapes in liquid crystals is potentially useful in the fabrication of self-healing composites and in stabilizing artificial frustrated phases. PMID:25994837

  19. Complex three-dimensional polymer-metal core-shell structures towards emission control.

    PubMed

    Ren, Lin; Wang, De-Gong; Niu, Li-Gang; Xu, Bin-Bin; Song, Jun-Feng; Chen, Qi-Dai; Sun, Hong-Bo

    2013-06-28

    We report the fabrication of three-dimensional periodic metal nickel nanostructures achieved by the combination of femtosecond laser-induced two-photon polymerization and electroless plating technology. We can control the deposition speed of 10 nm per second by adjusting the reaction time. The thermal stability is good under 500 °C for the three-dimensional graphite-lattice polymer structure with 200 nm nickel film. Optical reflectivity and thermal emission measurements under 550 °C showed that the fabricated metallic structure was thermally excited and emitted light at λ = 4.50, 4.95 μm. The emission peak wavelengths agree with the absorption peaks. These data demonstrate that creating metallic photonic crystals by incorporation of metals to laser-fabricated templates is a simple and cost-efficient method. The emitters can work at such low temperatures, which is more important for realistic operation in applications. PMID:23666225

  20. Structured light optical microscopy for three-dimensional reconstruction of technical surfaces

    NASA Astrophysics Data System (ADS)

    Kettel, Johannes; Reinecke, Holger; Müller, Claas

    2016-04-01

    In microsystems technology quality control of micro structured surfaces with different surface properties is playing an ever more important role. The process of quality control incorporates three-dimensional (3D) reconstruction of specularand diffusive reflecting technical surfaces. Due to the demand on high measurement accuracy and data acquisition rates, structured light optical microscopy has become a valuable solution to solve this problem providing high vertical and lateral resolution. However, 3D reconstruction of specular reflecting technical surfaces still remains a challenge to optical measurement principles. In this paper we present a measurement principle based on structured light optical microscopy which enables 3D reconstruction of specular- and diffusive reflecting technical surfaces. It is realized using two light paths of a stereo microscope equipped with different magnification levels. The right optical path of the stereo microscope is used to project structured light onto the object surface. The left optical path is used to capture the structured illuminated object surface with a camera. Structured light patterns are generated by a Digital Light Processing (DLP) device in combination with a high power Light Emitting Diode (LED). Structured light patterns are realized as a matrix of discrete light spots to illuminate defined areas on the object surface. The introduced measurement principle is based on multiple and parallel processed point measurements. Analysis of the measured Point Spread Function (PSF) by pattern recognition and model fitting algorithms enables the precise calculation of 3D coordinates. Using exemplary technical surfaces we demonstrate the successful application of our measurement principle.

  1. Three dimensional optical manipulation and structural imaging of soft materials by use of laser tweezers and multimodal nonlinear microscopy.

    PubMed

    Trivedi, Rahul P; Lee, Taewoo; Bertness, Kris A; Smalyukh, Ivan I

    2010-12-20

    We develop an integrated system of holographic optical trapping and multimodal nonlinear microscopy and perform simultaneous three-dimensional optical manipulation and non-invasive structural imaging of composite soft-matter systems. We combine different nonlinear microscopy techniques such as coherent anti-Stokes Raman scattering, multi-photon excitation fluorescence and multi-harmonic generation, and use them for visualization of long-range molecular order in soft materials by means of their polarized excitation and detection. The combined system enables us to accomplish manipulation in composite soft materials such as colloidal inclusions in liquid crystals as well as imaging of each separate constituents of the composite material in different nonlinear optical modalities. We also demonstrate optical generation and control of topological defects and simultaneous reconstruction of their three-dimensional long-range molecular orientational patterns from the nonlinear optical images.

  2. Evaluation of optical flow algorithms for tracking endocardial surfaces on three-dimensional ultrasound data

    NASA Astrophysics Data System (ADS)

    Duan, Qi; Angelini, Elsa D.; Herz, Susan L.; Ingrassia, Christopher M.; Gerard, Olivier; Costa, Kevin D.; Holmes, Jeffrey W.; Laine, Andrew F.

    2005-04-01

    With relatively high frame rates and the ability to acquire volume data sets with a stationary transducer, 3D ultrasound systems, based on matrix phased array transducers, provide valuable three-dimensional information, from which quantitative measures of cardiac function can be extracted. Such analyses require segmentation and visual tracking of the left ventricular endocardial border. Due to the large size of the volumetric data sets, manual tracing of the endocardial border is tedious and impractical for clinical applications. Therefore the development of automatic methods for tracking three-dimensional endocardial motion is essential. In this study, we evaluate a four-dimensional optical flow motion tracking algorithm to determine its capability to follow the endocardial border in three dimensional ultrasound data through time. The four-dimensional optical flow method was implemented using three-dimensional correlation. We tested the algorithm on an experimental open-chest dog data set and a clinical data set acquired with a Philips' iE33 three-dimensional ultrasound machine. Initialized with left ventricular endocardial data points obtained from manual tracing at end-diastole, the algorithm automatically tracked these points frame by frame through the whole cardiac cycle. A finite element surface was fitted through the data points obtained by both optical flow tracking and manual tracing by an experienced observer for quantitative comparison of the results. Parameterization of the finite element surfaces was performed and maps displaying relative differences between the manual and semi-automatic methods were compared. The results showed good consistency between manual tracing and optical flow estimation on 73% of the entire surface with fewer than 10% difference. In addition, the optical flow motion tracking algorithm greatly reduced processing time (about 94% reduction compared to human involvement per cardiac cycle) for analyzing cardiac function in three-dimensional

  3. Optical cell separation from three-dimensional environment in photodegradable hydrogels for pure culture techniques

    PubMed Central

    Tamura, Masato; Yanagawa, Fumiki; Sugiura, Shinji; Takagi, Toshiyuki; Sumaru, Kimio; Matsui, Hirofumi; Kanamori, Toshiyuki

    2014-01-01

    Cell sorting is an essential and efficient experimental tool for the isolation and characterization of target cells. A three-dimensional environment is crucial in determining cell behavior and cell fate in biological analysis. Herein, we have applied photodegradable hydrogels to optical cell separation from a 3D environment using a computer-controlled light irradiation system. The hydrogel is composed of photocleavable tetra-arm polyethylene glycol and gelatin, which optimized cytocompatibility to adjust a composition of crosslinker and gelatin. Local light irradiation could degrade the hydrogel corresponding to the micropattern image designed on a laptop; minimum resolution of photodegradation was estimated at 20 µm. Light irradiation separated an encapsulated fluorescent microbead without any contamination of neighbor beads, even at multiple targets. Upon selective separation of target cells in the hydrogels, the separated cells have grown on another dish, resulting in pure culture. Cell encapsulation, light irradiation and degradation products exhibited negligible cytotoxicity in overall process. PMID:24810563

  4. Optical cell separation from three-dimensional environment in photodegradable hydrogels for pure culture techniques.

    PubMed

    Tamura, Masato; Yanagawa, Fumiki; Sugiura, Shinji; Takagi, Toshiyuki; Sumaru, Kimio; Matsui, Hirofumi; Kanamori, Toshiyuki

    2014-01-01

    Cell sorting is an essential and efficient experimental tool for the isolation and characterization of target cells. A three-dimensional environment is crucial in determining cell behavior and cell fate in biological analysis. Herein, we have applied photodegradable hydrogels to optical cell separation from a 3D environment using a computer-controlled light irradiation system. The hydrogel is composed of photocleavable tetra-arm polyethylene glycol and gelatin, which optimized cytocompatibility to adjust a composition of crosslinker and gelatin. Local light irradiation could degrade the hydrogel corresponding to the micropattern image designed on a laptop; minimum resolution of photodegradation was estimated at 20 µm. Light irradiation separated an encapsulated fluorescent microbead without any contamination of neighbor beads, even at multiple targets. Upon selective separation of target cells in the hydrogels, the separated cells have grown on another dish, resulting in pure culture. Cell encapsulation, light irradiation and degradation products exhibited negligible cytotoxicity in overall process. PMID:24810563

  5. Estimation of trapping position in three-dimensional off-axis trapping with optical vortices

    NASA Astrophysics Data System (ADS)

    Ando, Taro; Otsu, Tomoko; Takiguchi, Yu; Ohtake, Yoshiyuki; Toyoda, Haruyoshi; Itoh, Hiroyasu

    2014-08-01

    Dynamics of micrometer-sized dielectric objects can be controlled by optical tweezers with scanning light, however, the trapped objects fail to track the scan when drag exceeds the trapping by too quick movement. On the other hand, optical vortices (OVs), which have a property of carrying angular momenta, can directly control torque on objects rather than their position. Laguerre-Gaussian (LG) beams are the most familiar examples of OV and have been studied extensively so far. Revolution of the objects trapped by the LG beams provides typical models of nonequilibrium statistical system, but stable mid-water trapping by the LG beams becomes essential to evaluate physical properties of the system without extrinsic hydrodynamic effects,. Nevertheless, off-axis revolutions of small objects trapped in mid-water by the LG beams have not yet been established with secure evidences. Here we report stable off-axis trapping of dielectric spheres in mid-water using high-quality LG beams generated by a holographic complex-amplitude modulation method. Direct evidence of the three-dimensional off-axis LG trapping was established via estimating the trapping position by measuring the change of revolution radii upon pressing the spheres onto glass walls. Resultantly, the axial trapping position was determined as about half the wavelength behind the beam waist position. This result provides a direct scientific evidence for possibility of off-axis three-dimensional trapping with a single LG beam, moreover, suggests applications as powerful tools for studying energy-conversion mechanisms and nonequilibrium nature in biological molecules under torque.

  6. Reconfigurable three-dimensional optical route formed by fiber-optic pseudo-Bessel beam arrays

    NASA Astrophysics Data System (ADS)

    Kim, Jongki; Lee, Sungrae; Jeong, Yoonseob; Shin, Jeon-Soo; Oh, Kyunghwan

    2011-10-01

    We present a novel implementation of Fourier optics along a single strand of hybrid optical fiber in a monolithic manner that can generate a highly efficient pseudo-Bessel beam. The incident fundamental mode of an optical fiber is adiabatically transformed to multiple ring modes by interference within a coreless silica fiber, which serves as a micro annulus apertures. A micro polymer lens was formed at the end face to complete the Fourier-transform providing a pseudo-Bessel beam at the output. Efficient multiple particle trapping experiments for both polystyrene beads were realized over 1 mm distance along the pseudo-Bessel beam. Furthermore all-optical transport of the trapped particles along a three dimensional optical route was demonstrated by spatially multiplexing pseudo-Bessel beams via multi mode interference (MMI) type Bessel beam generators. 1x3 pseudo-Bessel beam multiplexer was installed in the water based solution with 10mm(micro meter?) polystyrene beads. After a polystyrene particle was trapped by pseudo-Bessel beam, the initial acceleration was observed as 150μm/s2. The final velocity of the trapped particle maintained about 300μm/s with 40μm/s undulation due to pseudo-Bessel beam crossing points. The spatial multiplexing of fiber optic pseudo- Bessel beam arrays could make a new building block to realize reconfigurable all-optical transportation of particles.

  7. New advances in three-dimensional controlled-sourceelectromagnetic inversion

    SciTech Connect

    Commer, Michael; Newman, Gregory A.

    2007-05-19

    New techniques for improving both the computational andimaging performance of the three dimensional (3D) electromagnetic inverseproblem are presented. A non-linear conjugate gradient algorithm is theframework of the inversion scheme. Full wave equation modelling forcontrolled sources is utilized for data simulation along with anefficient gradient computation approach for the model update. Improvingthe modelling efficiency of the 3D finite difference method involves theseparation of the potentially large modelling mesh, defining the set ofmodel parameters, from the computational finite difference meshes usedfor field simulation. Grid spacings and thus overall grid sizes can bereduced and optimized according to source frequencies and source-receiveroffsets of a given input data set. Further computational efficiency isobtained by combining different levels of parallelization. While theparallel scheme allows for an arbitrarily large number of parallel tasks,the relative amount of message passing is kept constant. Imageenhancement is achieved by model parameter transformation functions,which enforce bounded conductivity parameters and thus prevent parameterovershoots. Further, a remedy for treating distorted data within theinversion process is presented. Data distortions simulated here includepositioning errors and a highly conductive overburden, hiding the desiredtarget signal. The methods are demonstrated using both synthetic andfield data.

  8. Optical chracterization and lasing in three-dimensional opal-structures

    NASA Astrophysics Data System (ADS)

    Nishijima, Yoshiaki; Juodkazis, Saulius

    2015-06-01

    The lasing properties of dye-permeated opal pyramidal structures are compared with the lasing properties of opal films. The opal-structures studied were made by sedimentation of micro-spheres and by sol-gel inversion of the direct-opals. Forced-sedimentation by centrifugation inside wet-etched pyramidal pits on silicon surfaces was used to improve the structural quality of the direct-opal structures. Single crystalline pyramids with the base length of ˜ 100 µm were formed by centrifuged sedimentation. The lasing of dyes in the well-ordered crystalline and poly-crystalline structures showed a distinct multi-modal spectrum. Gain via a distributed feedback was responsible for the lasing since the photonic band gap was negligible in a low refractive index contrast medium; the indices of silica and ethylene glycol are 1.46 and 1.42, respectively. A disordered lasing spectrum was observed from opal films with structural defects and multi-domain regions. The three dimensional structural quality of the structures was assessed by in situ optical diffraction and confocal fluorescence. A correlation between the lasing spectrum and the three-dimensional structural quality was established. Lasing threshold of a sulforhodamine dye in a silica opal was controlled via Förster mechanism by addition of a donor rhodamine 6G dye. The lasing spectrum had a well-ordered modal structure which was spectrally stable at different excitation powers. The sharp lasing threshold characterized by a spontaneous emission coupling ratio β ' 10-2 was obtained.

  9. Customized three-dimensional printed optical phantoms with user defined absorption and scattering

    NASA Astrophysics Data System (ADS)

    Pannem, Sanjana; Sweer, Jordan; Diep, Phuong; Lo, Justine; Snyder, Michael; Stueber, Gabriella; Zhao, Yanyu; Tabassum, Syeda; Istfan, Raeef; Wu, Junjie; Erramilli, Shyamsunder; Roblyer, Darren M.

    2016-03-01

    The use of reliable tissue-simulating phantoms spans multiple applications in spectroscopic imaging including device calibration and testing of new imaging procedures. Three-dimensional (3D) printing allows for the possibility of optical phantoms with arbitrary geometries and spatially varying optical properties. We recently demonstrated the ability to 3D print tissue-simulating phantoms with customized absorption (μa) and reduced scattering (μs`) by incorporating nigrosin, an absorbing dye, and titanium dioxide (TiO2), a scattering agent, to acrylonitrile butadiene styrene (ABS) during filament extrusion. A physiologically relevant range of μa and μs` was demonstrated with high repeatability. We expand our prior work here by evaluating the effect of two important 3D-printing parameters, percent infill and layer height, on both μa and μs`. 2 cm3 cubes were printed with percent infill ranging from 10% to 100% and layer height ranging from 0.15 to 0.40 mm. The range in μa and μs` was 27.3% and 19.5% respectively for different percent infills at 471 nm. For varying layer height, the range in μa and μs` was 27.8% and 15.4% respectively at 471 nm. These results indicate that percent infill and layer height substantially alter optical properties and should be carefully controlled during phantom fabrication. Through the use of inexpensive hobby-level printers, the fabrication of optical phantoms may advance the complexity and availability of fully customizable phantoms over multiple spatial scales. This technique exhibits a wider range of adaptability than other common methods of fabricating optical phantoms and may lead to improved instrument characterization and calibration.

  10. Parameter estimation of atherosclerotic tissue optical properties from three-dimensional intravascular optical coherence tomography

    PubMed Central

    Gargesha, Madhusudhana; Shalev, Ronny; Prabhu, David; Tanaka, Kentaro; Rollins, Andrew M.; Costa, Marco; Bezerra, Hiram G.; Wilson, David L.

    2015-01-01

    Abstract. We developed robust, three-dimensional methods, as opposed to traditional A-line analysis, for estimating the optical properties of calcified, fibrotic, and lipid atherosclerotic plaques from in vivo coronary artery intravascular optical coherence tomography clinical pullbacks. We estimated attenuation μt and backscattered intensity I0 from small volumes of interest annotated by experts in 35 pullbacks. Some results were as follows: noise reduction filtering was desirable, parallel line (PL) methods outperformed individual line methods, root mean square error was the best goodness-of-fit, and α-trimmed PL (α-T-PL) was the best overall method. Estimates of μt were calcified (3.84±0.95  mm−1), fibrotic (2.15±1.08  mm−1), and lipid (9.99±2.37  mm−1), similar to those in the literature, and tissue classification from optical properties alone was promising. PMID:26158087

  11. Volumetric display system based on three-dimensional scanning of inclined optical image.

    PubMed

    Miyazaki, Daisuke; Shiba, Kensuke; Sotsuka, Koji; Matsushita, Kenji

    2006-12-25

    A volumetric display system based on three-dimensional (3D) scanning of an inclined image is reported. An optical image of a two-dimensional (2D) display, which is a vector-scan display monitor placed obliquely in an optical imaging system, is moved laterally by a galvanometric mirror scanner. Inclined cross-sectional images of a 3D object are displayed on the 2D display in accordance with the position of the image plane to form a 3D image. Three-dimensional images formed by this display system satisfy all the criteria for stereoscopic vision because they are real images formed in a 3D space. Experimental results of volumetric imaging from computed-tomography images and 3D animated images are presented.

  12. Three-dimensional control of the helical axis of a chiral nematic liquid crystal by light

    NASA Astrophysics Data System (ADS)

    Zheng, Zhi-Gang; Li, Yannian; Bisoyi, Hari Krishna; Wang, Ling; Bunning, Timothy J.; Li, Quan

    2016-03-01

    Chiral nematic liquid crystals—otherwise referred to as cholesteric liquid crystals (CLCs)—are self-organized helical superstructures that find practical application in, for example, thermography, reflective displays, tuneable colour filters and mirrorless lasing. Dynamic, remote and three-dimensional control over the helical axis of CLCs is desirable, but challenging. For example, the orientation of the helical axis relative to the substrate can be changed from perpendicular to parallel by applying an alternating-current electric field, by changing the anchoring conditions of the substrate, or by altering the topography of the substrate’s surface; separately, in-plane rotation of the helical axis parallel to the substrate can be driven by a direct-current field. Here we report three-dimensional manipulation of the helical axis of a CLC, together with inversion of its handedness, achieved solely with a light stimulus. We use this technique to carry out light-activated, wide-area, reversible two-dimensional beam steering—previously accomplished using complex integrated systems and optical phased arrays. During the three-dimensional manipulation by light, the helical axis undergoes, in sequence, a reversible transition from perpendicular to parallel, followed by in-plane rotation on the substrate surface. Such reversible manipulation depends on experimental parameters such as cell thickness, surface anchoring condition, and pitch length. Because there is no thermal relaxation, the system can be driven either forwards or backwards from any light-activated intermediate state. We also describe reversible photocontrol between a two-dimensional diffraction state, a one-dimensional diffraction state and a diffraction ‘off’ state in a bilayer cell.

  13. Three-dimensional control of the helical axis of a chiral nematic liquid crystal by light.

    PubMed

    Zheng, Zhi-gang; Li, Yannian; Bisoyi, Hari Krishna; Wang, Ling; Bunning, Timothy J; Li, Quan

    2016-03-17

    Chiral nematic liquid crystals--otherwise referred to as cholesteric liquid crystals (CLCs)--are self-organized helical superstructures that find practical application in, for example, thermography, reflective displays, tuneable colour filters and mirrorless lasing. Dynamic, remote and three-dimensional control over the helical axis of CLCs is desirable, but challenging. For example, the orientation of the helical axis relative to the substrate can be changed from perpendicular to parallel by applying an alternating-current electric field, by changing the anchoring conditions of the substrate, or by altering the topography of the substrate's surface; separately, in-plane rotation of the helical axis parallel to the substrate can be driven by a direct-current field. Here we report three-dimensional manipulation of the helical axis of a CLC, together with inversion of its handedness, achieved solely with a light stimulus. We use this technique to carry out light-activated, wide-area, reversible two-dimensional beam steering--previously accomplished using complex integrated systems and optical phased arrays. During the three-dimensional manipulation by light, the helical axis undergoes, in sequence, a reversible transition from perpendicular to parallel, followed by in-plane rotation on the substrate surface. Such reversible manipulation depends on experimental parameters such as cell thickness, surface anchoring condition, and pitch length. Because there is no thermal relaxation, the system can be driven either forwards or backwards from any light-activated intermediate state. We also describe reversible photocontrol between a two-dimensional diffraction state, a one-dimensional diffraction state and a diffraction 'off' state in a bilayer cell. PMID:26950601

  14. Three dimensional visualization to support command and control

    SciTech Connect

    Van Slambrook, G.A.

    1997-04-01

    Virtual reality concepts are changing the way one thinks about and with computers. The concepts have already proven their potential usefulness in a broad range of applications. This research was concerned with exploring and demonstrating the utility of virtual reality in robotics and satellite command and control applications. The robotics work addressed the need to quickly build accurate graphical models of physical environments by allowing a user to interactively build a model of a remote environment by superimposing stereo graphics onto live stereo video. The satellite work addressed the fusion of multiple data sets or models into one synergistic display for more effective training, design, and command and control of satellite systems.

  15. Structurally Efficient Three-dimensional Metamaterials with Controllable Thermal Expansion

    PubMed Central

    Xu, Hang; Pasini, Damiano

    2016-01-01

    The coefficient of thermal expansion (CTE) of architected materials, as opposed to that of conventional solids, can be tuned to zero by intentionally altering the geometry of their structural layout. Existing material architectures, however, achieve CTE tunability only with a sacrifice in structural efficiency, i.e. a drop in both their stiffness to mass ratio and strength to mass ratio. In this work, we elucidate how to resolve the trade-off between CTE tunability and structural efficiency and present a lightweight bi-material architecture that not only is stiffer and stronger than other 3D architected materials, but also has a highly tunable CTE. Via a combination of physical experiments on 3D fabricated prototypes and numeric simulations, we demonstrate how two distinct mechanisms of thermal expansion appearing in a tetrahedron, can be exploited in an Octet lattice to generate a large range of CTE values, including negative, zero, or positive, with no loss in structural efficiency. The novelty and simplicity of the proposed design as well as the ease in fabrication, make this bi-material architecture well-suited for a wide range of applications, including satellite antennas, space optical systems, precision instruments, thermal actuators, and MEMS. PMID:27721437

  16. Structurally Efficient Three-dimensional Metamaterials with Controllable Thermal Expansion

    NASA Astrophysics Data System (ADS)

    Xu, Hang; Pasini, Damiano

    2016-10-01

    The coefficient of thermal expansion (CTE) of architected materials, as opposed to that of conventional solids, can be tuned to zero by intentionally altering the geometry of their structural layout. Existing material architectures, however, achieve CTE tunability only with a sacrifice in structural efficiency, i.e. a drop in both their stiffness to mass ratio and strength to mass ratio. In this work, we elucidate how to resolve the trade-off between CTE tunability and structural efficiency and present a lightweight bi-material architecture that not only is stiffer and stronger than other 3D architected materials, but also has a highly tunable CTE. Via a combination of physical experiments on 3D fabricated prototypes and numeric simulations, we demonstrate how two distinct mechanisms of thermal expansion appearing in a tetrahedron, can be exploited in an Octet lattice to generate a large range of CTE values, including negative, zero, or positive, with no loss in structural efficiency. The novelty and simplicity of the proposed design as well as the ease in fabrication, make this bi-material architecture well-suited for a wide range of applications, including satellite antennas, space optical systems, precision instruments, thermal actuators, and MEMS.

  17. Three-dimensional modular control of human walking.

    PubMed

    Allen, Jessica L; Neptune, Richard R

    2012-08-01

    Recent studies have suggested that complex muscle activity during walking may be controlled using a reduced neural control strategy organized around the co-excitation of multiple muscles, or modules. Previous computer simulation studies have shown that five modules satisfy the sagittal-plane biomechanical sub-tasks of 2D walking. The present study shows that a sixth module, which contributes primarily to mediolateral balance control and contralateral leg swing, is needed to satisfy the additional non-sagittal plane demands of 3D walking. Body support was provided by Module 1 (hip and knee extensors, hip abductors) in early stance and Module 2 (plantarflexors) in late stance. In early stance, forward propulsion was provided by Module 4 (hamstrings), but net braking occurred due to Modules 1 and 2. Forward propulsion was provided by Module 2 in late stance. Module 1 accelerated the body medially throughout stance, dominating the lateral acceleration in early stance provided by Modules 4 and 6 (adductor magnus) and in late stance by Module 2, except near toe-off. Modules 3 (ankle dorsiflexors, rectus femoris) and 5 (hip flexors and adductors except adductor magnus) accelerated the ipsilateral leg forward in early swing whereas Module 4 decelerated the ipsilateral leg prior to heel-strike. Finally, Modules 1, 4 and 6 accelerated the contralateral leg forward prior to and during contralateral swing. Since the modules were based on experimentally measured muscle activity, these results provide further evidence that a simple neural control strategy involving muscle activation modules organized around task-specific biomechanical functions may be used to control complex human movements.

  18. Spatially controlled cell adhesion on three-dimensional substrates.

    PubMed

    Richter, Christine; Reinhardt, Martina; Giselbrecht, Stefan; Leisen, Daniel; Trouillet, Vanessa; Truckenmüller, Roman; Blau, Axel; Ziegler, Christiane; Welle, Alexander

    2010-10-01

    The microenvironment of cells in vivo is defined by spatiotemporal patterns of chemical and biophysical cues. Therefore, one important goal of tissue engineering is the generation of scaffolds with defined biofunctionalization in order to control processes like cell adhesion and differentiation. Mimicking extrinsic factors like integrin ligands presented by the extracellular matrix is one of the key elements to study cellular adhesion on biocompatible scaffolds. By using special thermoformable polymer films with anchored biomolecules micro structured scaffolds, e.g. curved and micro-patterned substrates, can be fabricated. Here, we present a novel strategy for the fabrication of micro-patterned scaffolds based on the "Substrate Modification and Replication by Thermoforming" (SMART) technology: The surface of a poly lactic acid membrane, having a low forming temperature of 60 degrees C and being initially very cell attractive, was coated with a photopatterned layer of poly(L-lysine) (PLL) and hyaluronic acid (VAHyal) to gain spatial control over cell adhesion. Subsequently, this modified polymer membrane was thermoformed to create an array of spherical microcavities with diameters of 300 microm for 3D cell culture. Human hepatoma cells (HepG2) and mouse fibroblasts (L929) were used to demonstrate guided cell adhesion. HepG2 cells adhered and aggregated exclusively within these cavities without attaching to the passivated surfaces between the cavities. Also L929 cells adhering very strongly on the pristine substrate polymer were effectively patterned by the cell repellent properties of the hyaluronic acid based hydrogel. This is the first time cell adhesion was controlled by patterned functionalization of a polymeric substrate with UV curable PLL-VAHyal in thermoformed 3D microstructures.

  19. Spatially controlled cell adhesion on three-dimensional substrates

    PubMed Central

    Richter, Christine; Reinhardt, Martina; Giselbrecht, Stefan; Leisen, Daniel; Trouillet, Vanessa; Truckenmüller, Roman; Blau, Axel; Ziegler, Christiane

    2010-01-01

    The microenvironment of cells in vivo is defined by spatiotemporal patterns of chemical and biophysical cues. Therefore, one important goal of tissue engineering is the generation of scaffolds with defined biofunctionalization in order to control processes like cell adhesion and differentiation. Mimicking extrinsic factors like integrin ligands presented by the extracellular matrix is one of the key elements to study cellular adhesion on biocompatible scaffolds. By using special thermoformable polymer films with anchored biomolecules micro structured scaffolds, e.g. curved and µ-patterned substrates, can be fabricated. Here, we present a novel strategy for the fabrication of µ-patterned scaffolds based on the “Substrate Modification and Replication by Thermoforming” (SMART) technology: The surface of a poly lactic acid membrane, having a low forming temperature of 60°C and being initially very cell attractive, was coated with a photopatterned layer of poly(L-lysine) (PLL) and hyaluronic acid (VAHyal) to gain spatial control over cell adhesion. Subsequently, this modified polymer membrane was thermoformed to create an array of spherical microcavities with diameters of 300 µm for 3D cell culture. Human hepatoma cells (HepG2) and mouse fibroblasts (L929) were used to demonstrate guided cell adhesion. HepG2 cells adhered and aggregated exclusively within these cavities without attaching to the passivated surfaces between the cavities. Also L929 cells adhering very strongly on the pristine substrate polymer were effectively patterned by the cell repellent properties of the hyaluronic acid based hydrogel. This is the first time cell adhesion was controlled by patterned functionalization of a polymeric substrate with UV curable PLL-VAHyal in thermoformed 3D microstructures. PMID:20480241

  20. Controlling tokamak geometry with three-dimensional magnetic perturbations

    SciTech Connect

    Bird, T. M.; Hegna, C. C.

    2014-10-15

    It is shown that small externally applied magnetic perturbations can significantly alter important geometric properties of magnetic flux surfaces in tokamaks. Through 3D shaping, experimentally relevant perturbation levels are large enough to influence turbulent transport and MHD stability in the pedestal region. It is shown that the dominant pitch-resonant flux surface deformations are primarily induced by non-resonant 3D fields, particularly in the presence of significant axisymmetric shaping. The spectral content of the applied 3D field can be used to control these effects.

  1. Security authentication with a three-dimensional optical phase code using random forest classifier.

    PubMed

    Markman, Adam; Carnicer, Artur; Javidi, Bahram

    2016-06-01

    An object with a unique three-dimensional (3D) optical phase mask attached is analyzed for security and authentication. These 3D optical phase masks are more difficult to duplicate or to have a mathematical formulation compared with 2D masks and thus have improved security capabilities. A quick response code was modulated using a random 3D optical phase mask generating a 3D optical phase code (OPC). Due to the scattering of light through the 3D OPC, a unique speckle pattern based on the materials and structure in the 3D optical phase mask is generated and recorded on a CCD device. Feature extraction is performed by calculating the mean, variance, skewness, kurtosis, and entropy for each recorded speckle pattern. The random forest classifier is used for authentication. Optical experiments demonstrate the feasibility of the authentication scheme. PMID:27409445

  2. Dual focused coherent beams for three-dimensional optical trapping and continuous rotation of metallic nanostructures

    NASA Astrophysics Data System (ADS)

    Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun

    2016-07-01

    Metallic nanoparticles and nanowires are extremely important for nanoscience and nanotechnology. Techniques to optically trap and rotate metallic nanostructures can enable their potential applications. However, because of the destabilizing effects of optical radiation pressure, the optical trapping of large metallic particles in three dimensions is challenging. Additionally, the photothermal issues associated with optical rotation of metallic nanowires have far prevented their practical applications. Here, we utilize dual focused coherent beams to realize three-dimensional (3D) optical trapping of large silver particles. Continuous rotation of silver nanowires with frequencies measured in several hertz is also demonstrated based on interference-induced optical vortices with very low local light intensity. The experiments are interpreted by numerical simulations and calculations.

  3. Dual focused coherent beams for three-dimensional optical trapping and continuous rotation of metallic nanostructures

    PubMed Central

    Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun

    2016-01-01

    Metallic nanoparticles and nanowires are extremely important for nanoscience and nanotechnology. Techniques to optically trap and rotate metallic nanostructures can enable their potential applications. However, because of the destabilizing effects of optical radiation pressure, the optical trapping of large metallic particles in three dimensions is challenging. Additionally, the photothermal issues associated with optical rotation of metallic nanowires have far prevented their practical applications. Here, we utilize dual focused coherent beams to realize three-dimensional (3D) optical trapping of large silver particles. Continuous rotation of silver nanowires with frequencies measured in several hertz is also demonstrated based on interference-induced optical vortices with very low local light intensity. The experiments are interpreted by numerical simulations and calculations. PMID:27386838

  4. Dual focused coherent beams for three-dimensional optical trapping and continuous rotation of metallic nanostructures.

    PubMed

    Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun

    2016-01-01

    Metallic nanoparticles and nanowires are extremely important for nanoscience and nanotechnology. Techniques to optically trap and rotate metallic nanostructures can enable their potential applications. However, because of the destabilizing effects of optical radiation pressure, the optical trapping of large metallic particles in three dimensions is challenging. Additionally, the photothermal issues associated with optical rotation of metallic nanowires have far prevented their practical applications. Here, we utilize dual focused coherent beams to realize three-dimensional (3D) optical trapping of large silver particles. Continuous rotation of silver nanowires with frequencies measured in several hertz is also demonstrated based on interference-induced optical vortices with very low local light intensity. The experiments are interpreted by numerical simulations and calculations. PMID:27386838

  5. Design of virtual three-dimensional instruments for sound control

    NASA Astrophysics Data System (ADS)

    Mulder, Axel Gezienus Elith

    An environment for designing virtual instruments with 3D geometry has been prototyped and applied to real-time sound control and design. It enables a sound artist, musical performer or composer to design an instrument according to preferred or required gestural and musical constraints instead of constraints based only on physical laws as they apply to an instrument with a particular geometry. Sounds can be created, edited or performed in real-time by changing parameters like position, orientation and shape of a virtual 3D input device. The virtual instrument can only be perceived through a visualization and acoustic representation, or sonification, of the control surface. No haptic representation is available. This environment was implemented using CyberGloves, Polhemus sensors, an SGI Onyx and by extending a real- time, visual programming language called Max/FTS, which was originally designed for sound synthesis. The extension involves software objects that interface the sensors and software objects that compute human movement and virtual object features. Two pilot studies have been performed, involving virtual input devices with the behaviours of a rubber balloon and a rubber sheet for the control of sound spatialization and timbre parameters. Both manipulation and sonification methods affect the naturalness of the interaction. Informal evaluation showed that a sonification inspired by the physical world appears natural and effective. More research is required for a natural sonification of virtual input device features such as shape, taking into account possible co- articulation of these features. While both hands can be used for manipulation, left-hand-only interaction with a virtual instrument may be a useful replacement for and extension of the standard keyboard modulation wheel. More research is needed to identify and apply manipulation pragmatics and movement features, and to investigate how they are co-articulated, in the mapping of virtual object

  6. Microfluidic device for the formation of optically excitable, three-dimensional, compartmentalized motor units.

    PubMed

    Uzel, Sebastien G M; Platt, Randall J; Subramanian, Vidya; Pearl, Taylor M; Rowlands, Christopher J; Chan, Vincent; Boyer, Laurie A; So, Peter T C; Kamm, Roger D

    2016-08-01

    Motor units are the fundamental elements responsible for muscle movement. They are formed by lower motor neurons and their muscle targets, synapsed via neuromuscular junctions (NMJs). The loss of NMJs in neurodegenerative disorders (such as amyotrophic lateral sclerosis or spinal muscle atrophy) or as a result of traumatic injuries affects millions of lives each year. Developing in vitro assays that closely recapitulate the physiology of neuromuscular tissues is crucial to understand the formation and maturation of NMJs, as well as to help unravel the mechanisms leading to their degeneration and repair. We present a microfluidic platform designed to coculture myoblast-derived muscle strips and motor neurons differentiated from mouse embryonic stem cells (ESCs) within a three-dimensional (3D) hydrogel. The device geometry mimics the spinal cord-limb physical separation by compartmentalizing the two cell types, which also facilitates the observation of 3D neurite outgrowth and remote muscle innervation. Moreover, the use of compliant pillars as anchors for muscle strips provides a quantitative functional readout of force generation. Finally, photosensitizing the ESC provides a pool of source cells that can be differentiated into optically excitable motor neurons, allowing for spatiodynamic, versatile, and noninvasive in vitro control of the motor units. PMID:27493991

  7. Microfluidic device for the formation of optically excitable, three-dimensional, compartmentalized motor units

    PubMed Central

    Uzel, Sebastien G. M.; Platt, Randall J.; Subramanian, Vidya; Pearl, Taylor M.; Rowlands, Christopher J.; Chan, Vincent; Boyer, Laurie A.; So, Peter T. C.; Kamm, Roger D.

    2016-01-01

    Motor units are the fundamental elements responsible for muscle movement. They are formed by lower motor neurons and their muscle targets, synapsed via neuromuscular junctions (NMJs). The loss of NMJs in neurodegenerative disorders (such as amyotrophic lateral sclerosis or spinal muscle atrophy) or as a result of traumatic injuries affects millions of lives each year. Developing in vitro assays that closely recapitulate the physiology of neuromuscular tissues is crucial to understand the formation and maturation of NMJs, as well as to help unravel the mechanisms leading to their degeneration and repair. We present a microfluidic platform designed to coculture myoblast-derived muscle strips and motor neurons differentiated from mouse embryonic stem cells (ESCs) within a three-dimensional (3D) hydrogel. The device geometry mimics the spinal cord–limb physical separation by compartmentalizing the two cell types, which also facilitates the observation of 3D neurite outgrowth and remote muscle innervation. Moreover, the use of compliant pillars as anchors for muscle strips provides a quantitative functional readout of force generation. Finally, photosensitizing the ESC provides a pool of source cells that can be differentiated into optically excitable motor neurons, allowing for spatiodynamic, versatile, and noninvasive in vitro control of the motor units. PMID:27493991

  8. Three-Dimensional Composite Nanostructures for Lean NOx Emission Control

    SciTech Connect

    Gao, Pu-Xian

    2013-07-31

    This final report to the Department of Energy (DOE) and National Energy Technology Laboratory (NETL) for DE-EE0000210 covers the period from October 1, 2009 to July 31, 2013. Under this project, DOE awarded UConn about $1,248,242 to conduct the research and development on a new class of 3D composite nanostructure based catalysts for lean NOx emission control. Much of the material presented here has already been submitted to DOE/NETL in quarterly technical reports. In this project, through a scalable solution process, we have successfully fabricated a new class of catalytic reactors, i.e., the composite nanostructure array (nano-array) based catalytic converters. These nanocatalysts, distinct from traditional powder washcoat based catalytic converters, directly integrate monolithic substrates together with nanostructures with well-defined size and shape during the scalable hydrothermal process. The new monolithic nanocatalysts are demonstrated to be able to save raw materials including Pt-group metals and support metal oxides by an order of magnitude, while perform well at various oxidation (e.g., CO oxidation and NO oxidation) and reduction reactions (H{sub 2} reduction of NOx) involved in the lean NOx emissions. The size, shape and arrangement of the composite nanostructures within the monolithic substrates are found to be the key in enabling the drastically reduced materials usage while maintaining the good catalytic reactivity in the enabled devices. The further understanding of the reaction kinetics associated with the unique mass transport and surface chemistry behind is needed for further optimizing the design and fabrication of good nanostructure array based catalytic converters. On the other hand, the high temperature stability, hydrothermal aging stability, as well as S-poisoning resistance have been investigated in this project on the nanocatalysts, which revealed promising results toward good chemical and mechanical robustness, as well as S

  9. DNA origami-directed, discrete three-dimensional plasmonic tetrahedron nanoarchitectures with tailored optical chirality.

    PubMed

    Dai, Gaole; Lu, Xuxing; Chen, Zhong; Meng, Chun; Ni, Weihai; Wang, Qiangbin

    2014-04-23

    Discrete, three-dimensional (3D) gold nanoparticle (AuNP) tetrahedron nanoarchitectures are successfully self-assembled with DNA origami as template with high purity (>85%). A distinct plasmonic chiral response is experimentally observed from the AuNP tetrahedron nanoarchitectures and appears in a configuration-dependent manner. The chiral optical properties are then rationally engineered by modifying the structural parameters including the AuNP size and interparticle distance. Theoretical study of the AuNP tetrahedron nanoarchitectures shows the dependence of the chiral optical property on the AuNP size and interparticle distance, consistent with the ensemble averaged measurements.

  10. Review on recent progress of three-dimensional optical photonic crystal

    SciTech Connect

    Hsieh, Mei-Li; Kuang, Ping; Bur, James A.; Lin, Shawn-Yu; John, Sajeev

    2014-03-31

    Over the past two decades, the field of photonic-crystals has become one of the most influential realms of contemporary optics. In this paper, we will review two recent experimental progresses in three-dimensional photonic-crystal operating in optical wavelengths. The first is the observation of anomalous light-refraction, an acutely negative refraction, in a 3D photonic-crystal for light trapping, guiding and near-unity absorption. The second is the observation of quasi-coherent thermal emission from an all-metallic 3D photonic-crystal at elevated temperatures.

  11. Three-dimensional nanometry of vesicle transport in living cells using dual-focus imaging optics

    SciTech Connect

    Watanabe, Tomonobu M.; Sato, Takashi; Gonda, Kohsuke; Higuchi, Hideo . E-mail: higuchi@tubero.tohoku.ac.jp

    2007-07-20

    Dual-focus imaging optics for three-dimensional tracking of individual quantum dots has been developed to study the molecular mechanisms of motor proteins in cells. The new system has a high spatial and temporal precision, 2 nm in the x-y sample plane and 5 nm along the z-axis at a frame time of 2 ms. Three-dimensional positions of the vesicles labeled with quantum dots were detected in living cells. Vesicles were transported on the microtubules using 8-nm steps towards the nucleus. The steps had fluctuation of {approx}20 nm which were perpendicular to the axis of the microtubule but with the constant distance from the microtubule. The most of perpendicular movement was not synchronized with the 8-nm steps, indicating that dynein moved on microtubules without changing the protofilaments. When the vesicles changed their direction of movement toward the cell membrane, they moved perpendicular with the constant distance from the microtubule. The present method is powerful tool to investigate three dimensional movement of molecules in cells with nanometer and millisecond accuracy.

  12. Optical cryptography topology based on a three-dimensional particle-like distribution and diffractive imaging.

    PubMed

    Chen, Wen; Chen, Xudong

    2011-05-01

    In recent years, coherent diffractive imaging has been considered as a promising alternative for information retrieval instead of conventional interference methods. Coherent diffractive imaging using the X-ray light source has opened up a new research perspective for the measurement of non-crystalline and biological specimens, and can achieve unprecedentedly high resolutions. In this paper, we show how a three-dimensional (3D) particle-like distribution and coherent diffractive imaging can be applied for a study of optical cryptography. An optical multiple-random-phase-mask encoding approach is used, and the plaintext is considered as a series of particles distributed in a 3D space. A topology concept is also introduced into the proposed optical cryptosystem. During image decryption, a retrieval algorithm is developed to extract the plaintext from the ciphertexts. In addition, security and advantages of the proposed optical cryptography topology are also analyzed.

  13. Three-dimensional analysis of optical forces generated by an active tractor beam using radial polarization.

    PubMed

    Carretero, Luis; Acebal, Pablo; Blaya, Salvador

    2014-02-10

    We theoretically study the three-dimensional behavior of nanoparticles in an active optical conveyor. To do this, we solved the Langevin equation when the forces are generated by a focusing system at the near field. Analytical expressions for the optical forces generated by the optical conveyor were obtained by solving the Richards and Wolf vectorial diffraction integrals in an approximated form when a mask of two annular pupils is illuminated by a radially polarized Hermite-Gauss beam. Trajectories, in both the transverse plane and the longitudinal direction, are analyzed showing that the behavior of the optical conveyor can be optimized by conveniently choosing the configuration of the mask of the two annular pupils (inner and outer radius of the two rings) in order to trap and transport all particles at the focal plane. PMID:24663619

  14. Unconventional optical Tamm states in metal-terminated three-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Korovin, Alexander V.; Romanov, Sergei G.

    2016-03-01

    Unconventional optical Tamm surface states have been demonstrated in transmission and reflectance spectra of three-dimensional opal photonic crystals coated by thin metal films. These states appear in registry with diffraction resonances and localize the electromagnetic energy in asymmetric resonators formed by stacks of lattice planes and metal semishells. Tamm defect states provide the bypass for light at the edges of the Bragg diffraction resonances and thus reduce the diffraction efficiency. Despite the hidden nature of this effect, its magnitude is comparable to the extraordinary transmission associated with the surface-plasmon polaritons that are simultaneously excited at the surfaces of the corrugated metal films.

  15. Adaptive optics enables three-dimensional single particle tracking at the sub-millisecond scale

    NASA Astrophysics Data System (ADS)

    Juette, Manuel F.; Rivera-Molina, Felix E.; Toomre, Derek K.; Bewersdorf, Joerg

    2013-04-01

    We present the integration of an adaptive optics element into a feedback-driven single particle tracking microscope. Our instrument captures three-dimensional (3D) trajectories with down to 130 μs temporal resolution for dynamic studies on the nanoscale. Our 3D beam steering approach tracks particles over an axial range of >6 μm with ˜2 ms mechanical response times and isolates the sample from any tracking motion. Tracking of transport vesicles containing Alexa488-labeled transferrin glycoprotein in living cells demonstrates the speed and sensitivity of our instrument.

  16. Dynamic control of polarization-inverted modes in three-dimensionally trapped multiple nanogaps

    SciTech Connect

    Tamura, Mamoru; Iida, Takuya

    2015-12-28

    We propose a guiding principle for the dynamic control of polarization-inverted modes in multiple nanogaps for unconventional optical transitions of molecules at arbitrary three-dimensional spatial positions. Based on our developed self-consistent theory for the optical assembly of nanoparticles (NPs), we clarified that spherical silver NPs can be optically trapped and aligned in the light-propagating direction via longitudinally polarized light; they form a rod-like nano-composite with multiple nanogaps. During trapping, there is a possibility that an additional irradiation of linearly polarized far-field light may excite the bonding and anti-bonding dark plasmon modes with low radiative decay rate of several meV via cancellation of inverted polarization. Our finding reveals that not only the steep change in the enhanced intensity of light field but also the phase inversion of light field between the dynamically formed nanogaps will pave the way to the highly sensitive sensors for molecules, the unconventional chemical reactions, and so on.

  17. In-Situ Three-Dimensional Shape Rendering from Strain Values Obtained Through Optical Fiber Sensors

    NASA Technical Reports Server (NTRS)

    Chan, Hon Man (Inventor); Parker, Jr., Allen R. (Inventor)

    2015-01-01

    A method and system for rendering the shape of a multi-core optical fiber or multi-fiber bundle in three-dimensional space in real time based on measured fiber strain data. Three optical fiber cores arc arranged in parallel at 120.degree. intervals about a central axis. A series of longitudinally co-located strain sensor triplets, typically fiber Bragg gratings, are positioned along the length of each fiber at known intervals. A tunable laser interrogates the sensors to detect strain on the fiber cores. Software determines the strain magnitude (.DELTA.L/L) for each fiber at a given triplet, but then applies beam theory to calculate curvature, beading angle and torsion of the fiber bundle, and from there it determines the shape of the fiber in s Cartesian coordinate system by solving a series of ordinary differential equations expanded from the Frenet-Serrat equations. This approach eliminates the need for computationally time-intensive curve-tilting and allows the three-dimensional shape of the optical fiber assembly to be displayed in real-time.

  18. Vibration control for a nonlinear three-dimensional flexible manipulator trajectory tracking

    NASA Astrophysics Data System (ADS)

    Zhang, Yuanyuan; Liu, Jinkun; He, Wei

    2016-08-01

    This paper proposes an innovative approach to the trajectory tracking in three-dimensional space and vibration control problems in the presence of a nonlinear three-dimensional flexible manipulator based on the partial differential equation model. Unlike two-dimensional plane, we select spherical coordinates to describe the position of the end point in three-dimensional space. This novel approach makes it possible to realise the trajectory tracking by controlling the two angles in spherical coordinates, meanwhile, a vibration control scheme is proposed to restrain vibrations. In addition, the existence and uniqueness of solutions are demonstrated. Finally, the performance of the desired trajectory tracking, the proposed vibration control scheme and their convergence properties are demonstrated by numerical simulations.

  19. Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe5

    DOE PAGES

    Chen, R. Y.; Gu, G. D.; Zhang, S. J.; Schneeloch, J. A.; Zhang, C.; Li, Q.; Wang, N. L.

    2015-08-05

    Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. Additionally, an extremely sharp peak shows upmore » in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.« less

  20. Optical properties of coupled three-dimensional Ge quantum dot crystals.

    PubMed

    Ma, Yingjie; Zhong, Zhenyang; Lv, Quan; Qiu, Weiyang; Wang, Xinjun; Zhou, Tong; Fan, Yongliang; Jiang, Zuimin

    2013-03-11

    We report on optical properties of coupled three-dimensional (3D) Ge quantum dot crystals (QDCs). With increasing the vertical periodic number of the QDCs, the photoluminescence (PL) spectral linewidth decreased exponentially, and so did the peak energy blueshift caused by increasing excitation power, which are attributed to the electronic coupling and thus the formation of miniband. In the PL spectra, the relative intensity of the transverse-optical (TO) phonon replica also decreases with increasing the vertical periodic number, which is attributed to the increased Brillouin-zone folding effect in vertical direction and therewith the relaxation of indirect transition nature of exciton recombination. Besides, the optical reflectivity at the interband transition energy was much more reduced for the QDCs than for the in-plane disordered QDs grown with the same parameters, indicating a higher interband absorption of the QDCs due to the miniband formation.

  1. Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe5

    NASA Astrophysics Data System (ADS)

    Chen, R. Y.; Zhang, S. J.; Schneeloch, J. A.; Zhang, C.; Li, Q.; Gu, G. D.; Wang, N. L.

    2015-08-01

    Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. In addition, an extremely sharp peak shows up in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.

  2. Optical tuning of three-dimensional photonic crystals fabricated by femtosecond direct writing

    NASA Astrophysics Data System (ADS)

    McPhail, Dennis; Straub, Martin; Gu, Min

    2005-08-01

    In this letter, we report on an optically tunable three-dimensional photonic crystal that exhibits main gaps in the 3-4μm range. The photonic crystal is manufactured via a femtosecond direct writing technique. Optical tuning is achieved by a luminary polling technique with a low-power polarized laser beam. The refractive index variation resulting from liquid-crystal rotation causes a shift in the photonic band gap of up to 65 nm with an extinction of transmission of up to 70% in the stacking direction. Unlike other liquid-crystal tuning techniques where a pregenerated structure is infiltrated, this optical tuning method is a one-step process that allows arbitrary structures to be written into a solid liquid-crystal-polymer composite and leads to a high dielectric contrast.

  3. Physical origin of the high energy optical response of three dimensional photonic crystals.

    PubMed

    Dorado, Luis A; Depine, Ricardo A; Lozano, Gabriel; Míguez, Hernán

    2007-12-24

    The physical origin of the optical response observed in three-dimensional photonic crystals when the photon wavelength is equal or lower than the lattice parameter still remains unsatisfactorily explained and is the subject of an intense and interesting debate. Herein we demonstrate for the first time that all optical spectra features in this high energy region of photonic crystals arise from electromagnetic resonances within the ordered array, modified by the interplay between these resonances with the opening of diffraction channels, the presence of imperfections and finite size effects. All these four phenomena are taken into account in our theoretical approach to the problem, which allows us to provide a full description of the observed optical response based on fundamental phenomena as well as to attain fair fittings of experimental results.

  4. Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe5

    SciTech Connect

    Chen, R. Y.; Gu, G. D.; Zhang, S. J.; Schneeloch, J. A.; Zhang, C.; Li, Q.; Wang, N. L.

    2015-08-05

    Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. Additionally, an extremely sharp peak shows up in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.

  5. Smart agile lens remote optical sensor for three-dimensional object shape measurements.

    PubMed

    Riza, Nabeel A; Reza, Syed Azer

    2010-03-01

    We demonstrate what is, to the best of our knowledge, the first electronically controlled variable focus lens (ECVFL)-based sensor for remote object shape sensing. Using a target illuminating laser, the axial depths of the shape features on a given object are measured by observing the intensity profile of the optical beam falling on the object surface and tuning the ECVFL focal length to form a minimum beam spot. Using a lens focal length control calibration table, the object feature depths are computed. Transverse measurement of the dimensions of each object feature is done using a surface-flooding technique that completely illuminates a given feature. Alternately, transverse measurements can also be made by the variable spatial sampling scan technique, where, depending upon the feature sizes, the spatial sampling spot beam size is controlled using the ECVFL. A proof-of-concept sensor is demonstrated using an optical beam from a laser source operating at a power of 10 mW and a wavelength of 633 nm. A three-dimensional (3D) test object constructed from LEGO building blocks forms has three mini-skyscraper structures labeled A, B, and C. The (x, y, z) dimensions for A, B, and C are (8 mm, 8 mm, 124.84 mm), (24.2 mm, 24.2 mm, 38.5 mm), and (15.86 mm, 15.86 mm, 86.74 mm), respectively. The smart sensor experimentally measured (x,y,z) dimensions for A, B, C are (7.95 mm, 7.95 mm, 120 mm), (24.1 mm, 24.1 mm, 37 mm), and (15.8 mm, 15.8 mm, 85 mm), respectively. The average shape sensor transverse measurement percentage errors for A, B, and C are +/-0.625%, +/-0.41%, and +/-0.38%, respectively. The average shape sensor axial measurement percentage errors for A, B, and C are +/-4.03%, +/-3.9%, and +/-2.01%, respectively. Applications for the proposed shape sensor include machine parts inspection, 3D object reconstruction, and animation.

  6. Three-dimensional printed optical phantoms with customized absorption and scattering properties.

    PubMed

    Diep, Phuong; Pannem, Sanjana; Sweer, Jordan; Lo, Justine; Snyder, Michael; Stueber, Gabriella; Zhao, Yanyu; Tabassum, Syeda; Istfan, Raeef; Wu, Junjie; Erramilli, Shyamsunder; Roblyer, Darren

    2015-11-01

    Three-dimensional (3D) printing offers the promise of fabricating optical phantoms with arbitrary geometry, but commercially available thermoplastics provide only a small range of physiologically relevant absorption (µa) and reduced scattering (µs`) values. Here we demonstrate customizable acrylonitrile butadiene styrene (ABS) filaments for dual extrusion 3D printing of tissue mimicking optical phantoms. µa and µs` values were adjusted by incorporating nigrosin and titanium dioxide (TiO2) in the filament extrusion process. A wide range of physiologically relevant optical properties was demonstrated with an average repeatability within 11.5% for µa and 7.71% for µs`. Additionally, a mouse-simulating phantom, which mimicked both the geometry and optical properties of a hairless mouse with an implanted xenograft tumor, was printed using dual extrusion methods. 3D printed tumor optical properties matched the live tumor with less than 3% error at a wavelength of 659 nm. 3D printing with user defined optical properties may provide a viable method for durable optically diffusive phantoms for instrument characterization and calibration.

  7. Three-dimensional printed optical phantoms with customized absorption and scattering properties

    PubMed Central

    Diep, Phuong; Pannem, Sanjana; Sweer, Jordan; Lo, Justine; Snyder, Michael; Stueber, Gabriella; Zhao, Yanyu; Tabassum, Syeda; Istfan, Raeef; Wu, Junjie; Erramilli, Shyamsunder; Roblyer, Darren

    2015-01-01

    Three-dimensional (3D) printing offers the promise of fabricating optical phantoms with arbitrary geometry, but commercially available thermoplastics provide only a small range of physiologically relevant absorption (µa) and reduced scattering (µs`) values. Here we demonstrate customizable acrylonitrile butadiene styrene (ABS) filaments for dual extrusion 3D printing of tissue mimicking optical phantoms. µa and µs` values were adjusted by incorporating nigrosin and titanium dioxide (TiO2) in the filament extrusion process. A wide range of physiologically relevant optical properties was demonstrated with an average repeatability within 11.5% for µa and 7.71% for µs`. Additionally, a mouse-simulating phantom, which mimicked both the geometry and optical properties of a hairless mouse with an implanted xenograft tumor, was printed using dual extrusion methods. 3D printed tumor optical properties matched the live tumor with less than 3% error at a wavelength of 659 nm. 3D printing with user defined optical properties may provide a viable method for durable optically diffusive phantoms for instrument characterization and calibration. PMID:26600987

  8. Speckle contrast optical tomography: A new method for deep tissue three-dimensional tomography of blood flow

    PubMed Central

    Varma, Hari M.; Valdes, Claudia P.; Kristoffersen, Anna K.; Culver, Joseph P.; Durduran, Turgut

    2014-01-01

    A novel tomographic method based on the laser speckle contrast, speckle contrast optical tomography (SCOT) is introduced that allows us to reconstruct three dimensional distribution of blood flow in deep tissues. This method is analogous to the diffuse optical tomography (DOT) but for deep tissue blood flow. We develop a reconstruction algorithm based on first Born approximation to generate three dimensional distribution of flow using the experimental data obtained from tissue simulating phantoms. PMID:24761306

  9. Three-dimensional surface reconstruction within noncontact diffuse optical tomography using structured light

    NASA Astrophysics Data System (ADS)

    Baum, Kirstin; Hartmann, Raimo; Bischoff, Tobias; Oelerich, Jan O.; Finkensieper, Stephan; Heverhagen, Johannes T.

    2012-12-01

    A main field in biomedical optics research is diffuse optical tomography, where intensity variations of the transmitted light traversing through tissue are detected. Mathematical models and reconstruction algorithms based on finite element methods and Monte Carlo simulations describe the light transport inside the tissue and determine differences in absorption and scattering coefficients. Precise knowledge of the sample's surface shape and orientation is required to provide boundary conditions for these techniques. We propose an integrated method based on structured light three-dimensional (3-D) scanning that provides detailed surface information of the object, which is usable for volume mesh creation and allows the normalization of the intensity dispersion between surface and camera. The experimental setup is complemented by polarization difference imaging to avoid overlaying byproducts caused by inter-reflections and multiple scattering in semitransparent tissue.

  10. Weyl points in three-dimensional optical lattices: synthetic magnetic monopoles in momentum space

    NASA Astrophysics Data System (ADS)

    Buljan, Hrvoje; Dubcek, Tena; Kennedy, Colin; Lu, Ling; Ketterle, Wolfgang; Soljacic, Marin

    2015-05-01

    We show that Hamiltonians with Weyl points can be realized for ultracold atoms using laser-assisted tunneling in three-dimensional (3D) optical lattices. Weyl points are synthetic magnetic monopoles that exhibit a robust, 3D linear dispersion (e.g., see). They are associated with many interesting topological states of matter, such as Weyl semimetals and chiral Weyl fermions. However, Weyl points have yet to be experimentally observed in any system. We show that this elusive goal is well-within experimental reach with an extension of the techniques recently used to obtain the Harper Hamiltonian. We propose using laser assisted tunneling to create a 3D optical lattice, with specifically designed hopping between lattice sites that breaks inversion symmetry. The design leads to creation of four Weyl points in the Brillouin zone of the lattice, which are verified to be monopoles of the synthetic magnetic field. Supported by the Unity through Knowledge Fund (Grant 5/13).

  11. Three-dimensionally interconnected multi-bus-line bidirectional optical backplane

    NASA Astrophysics Data System (ADS)

    Kim, Gicherl; Chen, Ray T.

    1999-09-01

    The concept of a three-dimensionally interconnected optical backplane for a high-performance system containing multichip module boards, operating at 850 nm, is introduced. The backplane reported here employs 2D vertical-cavity surface- emitting lasers (VCSELs) and photodetector arrays as transceivers. By integrating 250-micrometers -pitch 2D VCSELs, microlenses, and photodetector arrays into our backplane design, we have demonstrated a multi-bus-line optical backplane and experimentally realized this architecture with 2D VCSEL and detector arrays while using the third dimension as the signal-propagating direction. Such an approach greatly increases the aggregate bandwidth of the backplane. Packaging issues such as misalignment, cross talk, and signal-to-noise ratio are studied. Eye diagrams up to 1.5 GHz were obtained with clear eyes, and the frequency response of a single bus line shows a bandwidth of 2.5 THz.

  12. Three-dimensional time-resolved optical mammography of the uncompressed breast

    NASA Astrophysics Data System (ADS)

    Enfield, Louise C.; Gibson, Adam P.; Everdell, Nicholas L.; Delpy, David T.; Schweiger, Martin; Arridge, Simon R.; Richardson, Caroline; Keshtgar, Mohammad; Douek, Michael; Hebden, Jeremy C.

    2007-06-01

    Optical tomography is being developed as a means of detecting and specifying disease in the adult female breast. We present a series of clinical three-dimensional optical images obtained with a 32-channel time-resolved system and a liquid-coupled interface. Patients place their breasts in a hemispherical cup to which sources and detectors are coupled, and the remaining space is filled with a highly scattering fluid. A cohort of 38 patients has been scanned, with a variety of benign and malignant lesions. Images show that hypervascularization associated with tumors provides very high contrast due to increased absorption by hemoglobin. Only half of the fibroadenomas scanned could be observed, but of those that could be detected, all but one revealed an apparent increase in blood volume and a decrease in scatter and oxygen saturation.

  13. Three-dimensional time-resolved optical mammography of the uncompressed breast

    SciTech Connect

    Enfield, Louise C.; Gibson, Adam P.; Everdell, Nicholas L.; Delpy, David T.; Schweiger, Martin; Arridge, Simon R.; Richardson, Caroline; Keshtgar, Mohammad; Douek, Michael; Hebden, Jeremy C

    2007-06-10

    Optical tomography is being developed as a means of detecting and specifying disease in the adult female breast. We present a series of clinical three-dimensional optical images obtained with a 32-channel time-resolvedsystem and a liquid-coupled interface. Patients place their breasts in a hemispherical cup to whichsources and detectors are coupled, and the remaining space is filled with a highly scattering fluid. Acohort of 38 patients has been scanned, with a variety of benign and malignant lesions. Images show that hypervascularization associated with tumors provides very high contrast due to increased absorption by hemoglobin. Only half of the fibroadenomas scanned could be observed, but of those that could bedetected, all but one revealed an apparent increase in blood volume and a decrease in scatter and oxygen saturation.

  14. Probe of three-dimensional chiral topological insulators in an optical lattice.

    PubMed

    Wang, S-T; Deng, D-L; Duan, L-M

    2014-07-18

    We propose a feasible experimental scheme to realize a three-dimensional chiral topological insulator with cold fermionic atoms in an optical lattice, which is characterized by an integer topological invariant distinct from the conventional Z(2) topological insulators and has a remarkable macroscopic zero-energy flat band. To probe its property, we show that its characteristic surface states--the Dirac cones--can be probed through time-of-flight imaging or Bragg spectroscopy and the flat band can be detected via measurement of the atomic density profile in a weak global trap. The realization of this novel topological phase with a flat band in an optical lattice will provide a unique experimental platform to study the interplay between interaction and topology and open new avenues for application of topological states.

  15. Three-dimensional fuse deposition modeling of tissue-simulating phantom for biomedical optical imaging

    NASA Astrophysics Data System (ADS)

    Dong, Erbao; Zhao, Zuhua; Wang, Minjie; Xie, Yanjun; Li, Shidi; Shao, Pengfei; Cheng, Liuquan; Xu, Ronald X.

    2015-12-01

    Biomedical optical devices are widely used for clinical detection of various tissue anomalies. However, optical measurements have limited accuracy and traceability, partially owing to the lack of effective calibration methods that simulate the actual tissue conditions. To facilitate standardized calibration and performance evaluation of medical optical devices, we develop a three-dimensional fuse deposition modeling (FDM) technique for freeform fabrication of tissue-simulating phantoms. The FDM system uses transparent gel wax as the base material, titanium dioxide (TiO2) powder as the scattering ingredient, and graphite powder as the absorption ingredient. The ingredients are preheated, mixed, and deposited at the designated ratios layer-by-layer to simulate tissue structural and optical heterogeneities. By printing the sections of human brain model based on magnetic resonance images, we demonstrate the capability for simulating tissue structural heterogeneities. By measuring optical properties of multilayered phantoms and comparing with numerical simulation, we demonstrate the feasibility for simulating tissue optical properties. By creating a rat head phantom with embedded vasculature, we demonstrate the potential for mimicking physiologic processes of a living system.

  16. Three-dimensional fuse deposition modeling of tissue-simulating phantom for biomedical optical imaging.

    PubMed

    Dong, Erbao; Zhao, Zuhua; Wang, Minjie; Xie, Yanjun; Li, Shidi; Shao, Pengfei; Cheng, Liuquan; Xu, Ronald X

    2015-01-01

    Biomedical optical devices are widely used for clinical detection of various tissue anomalies. However, optical measurements have limited accuracy and traceability, partially owing to the lack of effective calibration methods that simulate the actual tissue conditions. To facilitate standardized calibration and performance evaluation of medical optical devices, we develop a three-dimensional fuse deposition modeling (FDM) technique for freeform fabrication of tissue-simulating phantoms. The FDM system uses transparent gel wax as the base material, titanium dioxide (TiO2 ) powder as the scattering ingredient, and graphite powder as the absorption ingredient. The ingredients are preheated, mixed, and deposited at the designated ratios layer-by-layer to simulate tissue structural and optical heterogeneities. By printing the sections of human brain model based on magnetic resonance images, we demonstrate the capability for simulating tissue structural heterogeneities. By measuring optical properties of multilayered phantoms and comparing with numerical simulation, we demonstrate the feasibility for simulating tissue optical properties. By creating a rat head phantom with embedded vasculature, we demonstrate the potential for mimicking physiologic processes of a living system.

  17. Chirp-pulse-compression three-dimensional lidar imager with fiber optics.

    PubMed

    Pearson, Guy N; Ridley, Kevin D; Willetts, David V

    2005-01-10

    A coherent three-dimensional (angle-angle-range) lidar imager using a master-oscillator-power-amplifier concept and operating at a wavelength of 1.5 microm with chirp-pulse compression is described. A fiber-optic delay line in the local oscillator path enables a single continuous-wave semiconductor laser source with a modulated drive waveform to generate both the constant-frequency local oscillator and the frequency chirp. A portion of this chirp is gated out and amplified by a two-stage fiber amplifier. The digitized return signal was compressed by cross correlating it with a sample of the outgoing pulse. In this way a 350-ns, 10-microJ pulse with a 250-MHz frequency sweep is compressed to a width of approximately 8 ns. With a 25-mm output aperture, the lidar has been used to produce three-dimensional images of hard targets out to a range of approximately 2 km with near-diffraction-limited angular resolution and submeter range resolution. PMID:15678779

  18. Chirp-pulse-compression three-dimensional lidar imager with fiber optics.

    PubMed

    Pearson, Guy N; Ridley, Kevin D; Willetts, David V

    2005-01-10

    A coherent three-dimensional (angle-angle-range) lidar imager using a master-oscillator-power-amplifier concept and operating at a wavelength of 1.5 microm with chirp-pulse compression is described. A fiber-optic delay line in the local oscillator path enables a single continuous-wave semiconductor laser source with a modulated drive waveform to generate both the constant-frequency local oscillator and the frequency chirp. A portion of this chirp is gated out and amplified by a two-stage fiber amplifier. The digitized return signal was compressed by cross correlating it with a sample of the outgoing pulse. In this way a 350-ns, 10-microJ pulse with a 250-MHz frequency sweep is compressed to a width of approximately 8 ns. With a 25-mm output aperture, the lidar has been used to produce three-dimensional images of hard targets out to a range of approximately 2 km with near-diffraction-limited angular resolution and submeter range resolution.

  19. Automatic characterization and segmentation of human skin using three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Hori, Yasuaki; Yasuno, Yoshiaki; Sakai, Shingo; Matsumoto, Masayuki; Sugawara, Tomoko; Madjarova, Violeta; Yamanari, Masahiro; Makita, Shuichi; Yasui, Takeshi; Araki, Tsutomu; Itoh, Masahide; Yatagai, Toyohiko

    2006-03-01

    A set of fully automated algorithms that is specialized for analyzing a three-dimensional optical coherence tomography (OCT) volume of human skin is reported. The algorithm set first determines the skin surface of the OCT volume, and a depth-oriented algorithm provides the mean epidermal thickness, distribution map of the epidermis, and a segmented volume of the epidermis. Subsequently, an en face shadowgram is produced by an algorithm to visualize the infundibula in the skin with high contrast. The population and occupation ratio of the infundibula are provided by a histogram-based thresholding algorithm and a distance mapping algorithm. En face OCT slices at constant depths from the sample surface are extracted, and the histogram-based thresholding algorithm is again applied to these slices, yielding a three-dimensional segmented volume of the infundibula. The dermal attenuation coefficient is also calculated from the OCT volume in order to evaluate the skin texture. The algorithm set examines swept-source OCT volumes of the skins of several volunteers, and the results show the high stability, portability and reproducibility of the algorithm.

  20. Three-Dimensional High-Resolution Optical/X-Ray Stereoscopic Tracking Velocimetry

    NASA Technical Reports Server (NTRS)

    Cha, Soyoung S.; Ramachandran, Naryanan

    2005-01-01

    Measurement of three-dimensional (3-D) three-component velocity fields is of great importance in a variety of research and industrial applications for understanding materials processing, fluid physics, and strain/displacement measurements. The 3-D experiments in these fields most likely inhibit the use of conventional techniques, which are based only on planar and optically-transparent-field observation. Here, we briefly review the current status of 3-D diagnostics for motion/velocity detection, for both optical and x-ray systems. As an initial step for providing 3-D capabilities, we have developed stereoscopic tracking velocimetry (STV) to measure 3-D flow/deformation through optical observation. The STV is advantageous in system simplicity, for continually observing 3-D phenomena in near real-time. In an effort to enhance the data processing through automation and to avoid the confusion in tracking numerous markers or particles, artificial neural networks are employed to incorporate human intelligence. Our initial optical investigations have proven the STV to be a very viable candidate for reliably measuring 3-D flow motions. With previous activities focused on improving the processing efficiency, overall accuracy, and automation based on the optical system, the current efforts is directed to the concurrent expansion to the x-ray system for broader experimental applications.

  1. Three-Dimensional High-Resolution Optical/X-Ray Stereoscopic Tracking Velocimetry

    NASA Technical Reports Server (NTRS)

    Cha, Soyoung S.; Ramachandran, Narayanan

    2004-01-01

    Measurement of three-dimensional (3-D) three-component velocity fields is of great importance in a variety of research and industrial applications for understanding materials processing, fluid physics, and strain/displacement measurements. The 3-D experiments in these fields most likely inhibit the use of conventional techniques, which are based only on planar and optically-transparent-field observation. Here, we briefly review the current status of 3-D diagnostics for motion/velocity detection, for both optical and x-ray systems. As an initial step for providing 3-D capabilities, we nave developed stereoscopic tracking velocimetry (STV) to measure 3-D flow/deformation through optical observation. The STV is advantageous in system simplicity, for continually observing 3- D phenomena in near real-time. In an effort to enhance the data processing through automation and to avoid the confusion in tracking numerous markers or particles, artificial neural networks are employed to incorporate human intelligence. Our initial optical investigations have proven the STV to be a very viable candidate for reliably measuring 3-D flow motions. With previous activities are focused on improving the processing efficiency, overall accuracy, and automation based on the optical system, the current efforts is directed to the concurrent expansion to the x-ray system for broader experimental applications.

  2. Three-Dimensional Electron Optics Model Developed for Traveling-Wave Tubes

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.

    2000-01-01

    A three-dimensional traveling-wave tube (TWT) electron beam optics model including periodic permanent magnet (PPM) focusing has been developed at the NASA Glenn Research Center at Lewis Field. This accurate model allows a TWT designer to develop a focusing structure while reducing the expensive and time-consuming task of building the TWT and hot-testing it (with the electron beam). In addition, the model allows, for the first time, an investigation of the effect on TWT operation of the important azimuthally asymmetric features of the focusing stack. The TWT is a vacuum device that amplifies signals by transferring energy from an electron beam to a radiofrequency (RF) signal. A critically important component is the focusing structure, which keeps the electron beam from diverging and intercepting the RF slow wave circuit. Such an interception can result in excessive circuit heating and decreased efficiency, whereas excessive growth in the beam diameter can lead to backward wave oscillations and premature saturation, indicating a serious reduction in tube performance. The most commonly used focusing structure is the PPM stack, which consists of a sequence of cylindrical iron pole pieces and opposite-polarity magnets. Typically, two-dimensional electron optics codes are used in the design of magnetic focusing devices. In general, these codes track the beam from the gun downstream by solving equations of motion for the electron beam in static-electric and magnetic fields in an azimuthally symmetric structure. Because these two-dimensional codes cannot adequately simulate a number of important effects, the simulation code MAFIA (solution of Maxwell's equations by the Finite-Integration-Algorithm) was used at Glenn to develop a three-dimensional electron optics model. First, a PPM stack was modeled in three dimensions. Then, the fields obtained using the magnetostatic solver were loaded into a particle-in-cell solver where the fully three-dimensional behavior of the beam

  3. Three dimensional time lapse imaging of live cell mitochondria with photothermal optical lock-in optical coherence microscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sison, Miguel; Chakrabortty, Sabyasachi; Extermann, Jerome; Nahas, Amir; Pache, Christophe; Weil, Tanja; Lasser, Theo

    2016-03-01

    The photothermal optical lock-in optical coherence microscope (poli-OCM) introduced molecular specificity to OCM imaging, which is conventionally, a label-free technique. Here we achieve three-dimensional live cell and mitochondria specific imaging using ~4nm protein-functionalized gold nanoparticles (AuNPs). These nanoparticles do not photobleach and we demonstrate they're suitability for long-term time lapse imaging. We compare the accuracy of labelling with these AuNPs using classical fluorescence confocal imaging with a standard mitochondria specific marker. Furthermore, time lapse poli-OCM imaging every 5 minutes over 1.5 hours period was achieved, revealing the ability for three-dimensional monitoring of mitochondria dynamics.

  4. Optical properties of three-dimensional P(St-MAA) photonic crystals on polyester fabrics

    NASA Astrophysics Data System (ADS)

    Liu, Guojin; Zhou, Lan; Wu, Yujiang; Wang, Cuicui; Fan, Qinguo; Shao, Jianzhong

    2015-04-01

    The three-dimensional (3D) photonic crystals with face-centered cubic (fcc) structure was fabricated on polyester fabrics, a kind of soft textile materials quite different from the conventional solid substrates, by gravitational sedimentation self-assembly of monodisperse P(St-MAA) colloidal microspheres. The optical properties of structural colors on polyester fabrics were investigated and the position of photonic band gap was characterized. The results showed that the color-tuning ways of the structural colors from photonic crystals were in accordance with Bragg's law and could be modulated by the size of P(St-MAA) colloidal microspheres and the viewing angles. The L∗a∗b∗ values of the structural colors generated from the assembled polyester fabrics were in agreement with their reflectance spectra. The photonic band gap position of photonic crystals on polyester fabrics could be consistently confirmed by reflectance and transmittance spectra.

  5. Simulation of radiation effects on three-dimensional computer optical memories

    NASA Technical Reports Server (NTRS)

    Moscovitch, M.; Emfietzoglou, D.

    1997-01-01

    A model was developed to simulate the effects of heavy charged-particle (HCP) radiation on the information stored in three-dimensional computer optical memories. The model is based on (i) the HCP track radial dose distribution, (ii) the spatial and temporal distribution of temperature in the track, (iii) the matrix-specific radiation-induced changes that will affect the response, and (iv) the kinetics of transition of photochromic molecules from the colored to the colorless isomeric form (bit flip). It is shown that information stored in a volume of several nanometers radius around the particle's track axis may be lost. The magnitude of the effect is dependent on the particle's track structure.

  6. Three-dimensional spectral domain optical coherence tomography in chronic exposure to welding arc.

    PubMed

    Saxena, Sandeep; Mishra, Nibha; Meyer, Carsten H

    2014-01-01

    Three-dimensional spectral domain optical coherence tomography was performed in a 26-year-old man with chronic exposure to welding arc. Advanced macular visualisation provided significant findings of inner segment-ellipsoid zone disruption with the presence of cystoid changes and hyper-reflective material in the area of disruption. The external limiting membrane was intact in both the eyes. C-scan retinal pigment epithelium fit map of the left eye revealed a well-delineated defect whereas the right eye showed a poorly delineated smaller defect. The hyper-reflective material can be hypothesised to originate from the disrupted photoreceptor layer. The hyper-reflective material was more evident in the left eye which could be correlated with more marked diminution of vision and a prominent yellow lesion at the fovea. PMID:24832707

  7. All-optical dynamical Casimir effect in a three-dimensional terahertz photonic band gap

    NASA Astrophysics Data System (ADS)

    Hagenmüller, David

    2016-06-01

    We identify an architecture for the observation of all-optical dynamical Casimir effect in realistic experimental conditions. We suggest that by integrating quantum wells in a three-dimensional (3D) photonic band-gap material made out of large-scale (˜200 -μ m ) germanium logs, it is possible to achieve ultrastrong light-matter coupling at terahertz frequencies for the cyclotron transition of a two-dimensional electron gas interacting with long-lived optical modes, in which vacuum Rabi splitting is comparable to the Landau level spacing. When a short, intense electromagnetic transient of duration ˜250 fs and carrying a peak magnetic field ˜5 T is applied to the structure, the cyclotron transition can be suddenly tuned on resonance with a desired photon mode, switching on the light-matter interaction and leading to a Casimir radiation emitted parallel to the quantum well plane. The radiation spectrum consists of sharp peaks with frequencies coinciding with engineered optical modes within the 3D photonic band gap, and its characteristics are extremely robust to the nonradiative damping which can be large in our system. Furthermore, the absence of continuum with associated low-energy excitations for both electromagnetic and electronic quantum states can prevent the rapid absorption of the photon flux which is likely to occur in other proposals for all-optical dynamical Casimir effect.

  8. Spatial correlations and optical properties in three-dimensional deterministic aperiodic structures

    PubMed Central

    Renner, Michael; Freymann, Georg von

    2015-01-01

    Photonic systems have strongly varying optical properties depending on the spatial correlations present in a given realization. In photonic crystals the correlations are spatially periodic forming Bravais lattices whereas the building blocks of an amorphous medium are randomly distributed without any long-range order. In this manuscript we study the optical properties of so-called deterministic aperiodic structures which fill the gap between the aforementioned two limiting cases. Within this group we vary the spectrum of the spatial correlations from being pure-point over singularly-continuous to absolutely-continuous. The desired correlations are created in direct-laser written three-dimensional polymer structures using one construction principle which allows us to attribute the optical behaviour solely to the encoded spectrum. Infrared reflection measurements reveal the characteristic response of each spectral type verifying the successful fabrication of large deterministic aperiodic structures. To prove the presence of the correlations in all directions we perform transmission experiments parallel to the substrate by means of micro-optical mirrors placed next to the structures. Transport measurements reveal a strong dependence of the effective beam width at the output facet on the encoded lattice type. Finally, we reproduce the lattice type dependent transport behavior in numerical calculations ruling out extrinsic experimental reasons for these findings. PMID:26268153

  9. Potential-based methodology for active sound control in three dimensional settings.

    PubMed

    Lim, H; Utyuzhnikov, S V; Lam, Y W; Kelly, L

    2014-09-01

    This paper extends a potential-based approach to active noise shielding with preservation of wanted sound in three-dimensional settings. The approach, which was described in a previous publication [Lim et al., J. Acoust. Soc. Am. 129(2), 717-725 (2011)], provides several significant advantages over conventional noise control methods. Most significantly, the methodology does not require any information including the characterization of sources, impedance boundary conditions and surrounding medium, and that the methodology automatically differentiates between the wanted and unwanted sound components. The previous publication proved the concept in one-dimensional conditions. In this paper, the approach for more realistic conditions is studied by numerical simulation and experimental validation in three-dimensional cases. The results provide a guideline to the implementation of the active shielding method with practical three-dimensional conditions. Through numerical simulation it is demonstrated that while leaving the wanted sound unchanged, the developed approach offers selective volumetric noise cancellation within a targeted domain. In addition, the method is implemented in a three-dimensional experiment with a white noise source in a semi-anechoic chamber. The experimental study identifies practical difficulties and limitations in the use of the approach for real applications. PMID:25190385

  10. Responses of Ventral Posterior Thalamus Neurons to Three-Dimensional Vestibular and Optic Flow Stimulation

    PubMed Central

    Meng, Hui

    2010-01-01

    Multisensory neurons tuned to both vestibular and visual motion (optic flow) signals are found in several cortical areas in the dorsal visual stream. Here we examine whether such convergence occurs subcortically in the macaque thalamus. We searched the ventral posterior nuclei, including the anterior pulvinar, as well as the ventro-lateral and ventral posterior lateral nuclei, areas that receive vestibular signals from brain stem and deep cerebellar nuclei. Approximately a quarter of cells responded to three-dimensional (3D) translational and/or rotational motion. More than half of the responsive cells were convergent, thus responded during both rotation and translation. The preferred axes of translation/rotation were distributed throughout 3D space. The majority of the neurons were excited, but some were inhibited, during rotation/translation in darkness. Only a couple of neurons were multisensory being tuned to both vestibular and optic flow stimuli. We conclude that multisensory vestibular/optic flow neurons, which are commonly found in cortical visual and visuomotor areas, are rare in the ventral posterior thalamus. PMID:19955294

  11. Structure of modes of a smoothly irregular integrated-optical four-layer three-dimensional waveguide

    SciTech Connect

    Egorov, Alexander A; Sevast'yanov, L A

    2009-06-30

    The asymptotic method and the method of coupled waves used to study an integrated-optical multilayer three-dimensional waveguide satisfying the conditions of a continuously variable effective refractive index are considered. Three-dimensional fields of smoothly deforming modes of a four-layer integrated-optical waveguide are described analytically. Explicit dependences of the contributions of the first order of smallness to the electric and magnetic field amplitudes of quasi-waveguide modes are obtained. The canonical type of quasi-wave equations describing the structure of quasi-TE and quasi-TM modes in a smoothly irregular four-layer integrated-optical three-dimensional waveguide is presented for the asymptotic method. By using the perturbation theory, shifts of complex propagation constants are obtained in an explicit form for these modes. The elaborated theory can be used to analyse structures from dielectric, magnetic and metamaterials in a rather broad wavelength range of electromagnetic waves. (waveguides. optical fibres)

  12. Hadron Optics in Three-Dimensional Invariant Coordinate Space from Deeply VirtualCompton Scattering

    SciTech Connect

    Brodsky, S.J.; Chakrabarti, D.; Harindranath, A.; Mukherjee, A.; Vary, J.P.

    2006-11-30

    The Fourier transform of the deeply virtual Compton scattering amplitude (DVCS) with respect to the skewness parameter {zeta} = Q{sup 2}/2p {center_dot} q can be used to provide an image of the target hadron in the boost-invariant variable {sigma}, the coordinate conjugate to light-front time {tau} = t + z/c. As an illustration, we construct a consistent covariant model of the DVCS amplitude and its associated generalized parton distributions using the quantum fluctuations of a fermion state at one loop in QED, thus providing a representation of the light-front wave functions of a lepton in {sigma} space. A consistent model for hadronic amplitudes can then be obtained by differentiating the light-front wave functions with respect to the bound-state mass. The resulting DVCS helicity amplitudes are evaluated as a function of {sigma} and the impact parameter {rvec b}{sub {perpendicular}}, thus providing a light-front image of the target hadron in a frame-independent three-dimensional light-front coordinate space. Models for the LFWFs of hadrons in (3 + 1) dimensions displaying confinement at large distances and conformal symmetry at short distances have been obtained using the AdS/CFT method. We also compute the LFWFs in this model in invariant three dimensional coordinate space. We find that in the models studied, the Fourier transform of the DVCS amplitudes exhibit diffraction patterns. The results are analogous to the diffractive scattering of a wave in optics where the distribution in ? measures the physical size of the scattering center in a one-dimensional system.

  13. Scalable two- and three-dimensional optical labels generated by 128-port encoder/decoder for optical packet switching.

    PubMed

    Matsumoto, Ryosuke; Kodama, Takahiro; Morita, Koji; Wada, Naoya; Kitayama, Ken-ichi

    2015-10-01

    This paper deals with massive number of optical code (OC) label generation and recognition for scalable optical packet switching (OPS) networks. In order to expand the system scalability of code label processing, we develop a record port count 128 x 128 optical encoder/decoder (E/D) and propose a novel three-dimensional (3-D) optical label combining code label with wavelength and polarization. In the experiment, we conduct a proof-of-concept demonstration of 4-code x 2-wavelength x 2-polarization and validate that the 3-D labeling scheme can consequently increase the available number of code label up to more than 1,000 labels. Real-time labeling performance using a field programmable gate array (FPGA)-based processor and crosstalk influence at an optical switch are also experimentally evaluated. PMID:26480089

  14. Three-dimensional imaging of artificial fingerprint by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Larin, Kirill V.; Cheng, Yezeng

    2008-03-01

    Fingerprint recognition is one of the popular used methods of biometrics. However, due to the surface topography limitation, fingerprint recognition scanners are easily been spoofed, e.g. using artificial fingerprint dummies. Thus, biometric fingerprint identification devices need to be more accurate and secure to deal with different fraudulent methods including dummy fingerprints. Previously, we demonstrated that Optical Coherence Tomography (OCT) images revealed the presence of the artificial fingerprints (made from different household materials, such as cement and liquid silicone rubber) at all times, while the artificial fingerprints easily spoofed the commercial fingerprint reader. Also we demonstrated that an analysis of the autocorrelation of the OCT images could be used in automatic recognition systems. Here, we exploited the three-dimensional (3D) imaging of the artificial fingerprint by OCT to generate vivid 3D image for both the artificial fingerprint layer and the real fingerprint layer beneath. With the reconstructed 3D image, it could not only point out whether there exists an artificial material, which is intended to spoof the scanner, above the real finger, but also could provide the hacker's fingerprint. The results of these studies suggested that Optical Coherence Tomography could be a powerful real-time noninvasive method for accurate identification of artificial fingerprints real fingerprints as well.

  15. In vivo endomicroscopy using three-dimensional optical coherence tomography and Fourier domain mode locked lasers

    NASA Astrophysics Data System (ADS)

    Adler, Desmond C.; Chen, Yu; Huber, Robert; Schmitt, Joseph; Connolly, James; Fujimoto, James G.

    2008-02-01

    We report an endoscopic optical coherence tomography (OCT) system based on a Fourier Domain Mode Locked (FDML) laser, a novel data acquisition (DAQ) system with optical frequency clocking, and a high-speed spiralscanning fiber probe. The system is capable of acquiring three-dimensional (3D) in vivo datasets at 100,000 axial lines/s and 50 frames/s, enabled by the high sweep rates of the FDML laser and the efficient data processing of the DAQ system. This high imaging rate allows densely-sampled 3D datasets to be acquired, giving a resolvable feature size of 9 μm x 20 μm x 7 μm (transverse x longitudinal x axial, XYZ). In vivo 3D endomicroscopy is demonstrated in the rabbit colon, where individual colonic crypts are clearly visualized and measured. With further improvements in DAQ technology, the imaging speed will be scalable to the hundreds of thousands of axial lines/s supported by FDML lasers.

  16. Three-dimensional, distendable bladder phantom for optical coherence tomography and white light cystoscopy

    PubMed Central

    Lurie, Kristen L.; Smith, Gennifer T.; Khan, Saara A.; Liao, Joseph C.; Ellerbee, Audrey K.

    2014-01-01

    Abstract. We describe a combination of fabrication techniques and a general process to construct a three-dimensional (3-D) phantom that mimics the size, macroscale structure, microscale surface topology, subsurface microstructure, optical properties, and functional characteristics of a cancerous bladder. The phantom also includes features that are recognizable in white light (i.e., the visual appearance of blood vessels), making it suitable to emulate the bladder for emerging white light+optical coherence tomography (OCT) cystoscopies and other endoscopic procedures of large, irregularly shaped organs. The fabrication process has broad applicability and can be generalized to OCT phantoms for other tissue types or phantoms for other imaging modalities. To this end, we also enumerate the nuances of applying known fabrication techniques (e.g., spin coating) to contexts (e.g., nonplanar, 3-D shapes) that are essential to establish their generalizability and limitations. We anticipate that this phantom will be immediately useful to evaluate innovative OCT systems and software being developed for longitudinal bladder surveillance and early cancer detection. PMID:24623158

  17. Nonlinear optical microscopy reveals invading endothelial cells anisotropically alter three-dimensional collagen matrices

    SciTech Connect

    Lee, P.-F.; Yeh, Alvin T.; Bayless, Kayla J.

    2009-02-01

    The interactions between endothelial cells (ECs) and the extracellular matrix (ECM) are fundamental in mediating various steps of angiogenesis, including cell adhesion, migration and sprout formation. Here, we used a noninvasive and non-destructive nonlinear optical microscopy (NLOM) technique to optically image endothelial sprouting morphogenesis in three-dimensional (3D) collagen matrices. We simultaneously captured signals from collagen fibers and endothelial cells using second harmonic generation (SHG) and two-photon excited fluorescence (TPF), respectively. Dynamic 3D imaging revealed EC interactions with collagen fibers along with quantifiable alterations in collagen matrix density elicited by EC movement through and morphogenesis within the matrix. Specifically, we observed increased collagen density in the area between bifurcation points of sprouting structures and anisotropic increases in collagen density around the perimeter of lumenal structures, but not advancing sprout tips. Proteinase inhibition studies revealed membrane-associated matrix metalloproteinase were utilized for sprout advancement and lumen expansion. Rho-associated kinase (p160ROCK) inhibition demonstrated that the generation of cell tension increased collagen matrix alterations. This study followed sprouting ECs within a 3D matrix and revealed that the advancing structures recognize and significantly alter their extracellular environment at the periphery of lumens as they progress.

  18. Structural- and optical-property characterization of three-dimensional branched ZnO nanospikes

    SciTech Connect

    Chia, M.Y.; Chiu, W.S.; Daud, S.N.H.; Khiew, P.S.; Radiman, S.; Abd-Shukor, R.; Hamid, M.A.A.

    2015-08-15

    Current study reports the synthesis of three-dimensional (3-D) ZnO nanospikes with anomalous optical property, where zinc stearate is adopted as a safe, common and low-cost precursor that undergoes thermal pyrolysis under non-hydrolytic approach. High resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM) result show that the as-synthesized 3-D ZnO nanospikes are constructed by bundle of nanorods that sprout radially outwards in random orientation. The possible growth mechanism is discussed by referring to the microscopy results. X-ray diffraction (XRD) pattern confirms that the nanospikes are highly crystalline, which existed in hexagonal wurtzite crystal structure. Optical absorption characterization shows that the onset absorption for the nanospikes is slightly red-shifted if compared to commercial ZnO and the corresponding bandgap energy is estimated to be 3.1 eV. The photoluminescene (PL) result of ZnO nanospikes indicate that its optical emission exhibits weak UV emission but very intense visible-light emission that ranged from green- up to red-region. The factors that contributed to the intriguing PL characteristic are discussed. Current finding would offer a versatile synthesis scheme in engineering advanced nanostructures with new design that exhibit congruent optical property. - Graphical abstract: Display Omitted - Highlights: • Pyrolysis of zinc stearate in synthesizing 3-D ZnO nanospikes • ZnO nanospikes possess bundle of nanorods that sprout out from the hexagonal stump • Growth mechanism is deduced to elucidate the morphological evolution from nanobullet to nanospike with branching topology • PL spectrum indicate that the nanospike exhibit prominent visible-light emission that ranged from green- to red-region.

  19. Three-dimensional planar-integrated optics: a comparative view with free-space optics

    NASA Astrophysics Data System (ADS)

    Lee, El-Hang; Song, Seok Ho

    2000-04-01

    This paper reports on the viability, effectiveness, versatility, and the utility of the concept of the planar integrated optical interconnection scheme with respect to the concept of the free-space interconnection scheme in realizing multiple integration of various micro/nano- photonic devices and components for applications in optical interconnection, optical circuits, optical switching, optical communication and information processing. Several planar optics schemes to detect parallel optical packet addresses in WDM switching networks, to perform a space- variant processing such as fractional correlation, and to construct multistage interconnection networks, have been successfully demonstrated in the 3D glass blocks. Using a gradient-index (GRIN) substrate as a signal propagation medium in the planar optics is a unique advantage, when compared to the free-space optics. We have demonstrated the GRIN-substrate concept by using six 1/4-pitch GRIN rod lenses and a vertical cavity surface emitting laser (VCSEL). The GRIN planar optics can be further extended to the use of 2D array of VCSEL microlasers and modulators in making massively parallel interconnects. A critical comparison between the planar integrated optics scheme and the free- space integrated scheme is given in terms of physics, engineering and technological concept.

  20. Three-dimensional Segmentation of Retinal Cysts from Spectral-domain Optical Coherence Tomography Images by the Use of Three-dimensional Curvelet Based K-SVD

    PubMed Central

    Esmaeili, Mahdad; Dehnavi, Alireza Mehri; Rabbani, Hossein; Hajizadeh, Fedra

    2016-01-01

    This paper presents a new three-dimensional curvelet transform based dictionary learning for automatic segmentation of intraretinal cysts, most relevant prognostic biomarker in neovascular age-related macular degeneration, from 3D spectral-domain optical coherence tomography (SD-OCT) images. In particular, we focus on the Spectralis SD-OCT (Heidelberg Engineering, Heidelberg, Germany) system, and show the applicability of our algorithm in the segmentation of these features. For this purpose, we use recursive Gaussian filter and approximate the corrupted pixels from its surrounding, then in order to enhance the cystoid dark space regions and future noise suppression we introduce a new scheme in dictionary learning and take curvelet transform of filtered image then denoise and modify each noisy coefficients matrix in each scale with predefined initial 3D sparse dictionary. Dark pixels between retinal pigment epithelium and nerve fiber layer that were extracted with graph theory are considered as cystoid spaces. The average dice coefficient for the segmentation of cystoid regions in whole 3D volume and with-in central 3 mm diameter on the MICCAI 2015 OPTIMA Cyst Segmentation Challenge dataset were found to be 0.65 and 0.77, respectively. PMID:27563573

  1. Three-dimensional Segmentation of Retinal Cysts from Spectral-domain Optical Coherence Tomography Images by the Use of Three-dimensional Curvelet Based K-SVD.

    PubMed

    Esmaeili, Mahdad; Dehnavi, Alireza Mehri; Rabbani, Hossein; Hajizadeh, Fedra

    2016-01-01

    This paper presents a new three-dimensional curvelet transform based dictionary learning for automatic segmentation of intraretinal cysts, most relevant prognostic biomarker in neovascular age-related macular degeneration, from 3D spectral-domain optical coherence tomography (SD-OCT) images. In particular, we focus on the Spectralis SD-OCT (Heidelberg Engineering, Heidelberg, Germany) system, and show the applicability of our algorithm in the segmentation of these features. For this purpose, we use recursive Gaussian filter and approximate the corrupted pixels from its surrounding, then in order to enhance the cystoid dark space regions and future noise suppression we introduce a new scheme in dictionary learning and take curvelet transform of filtered image then denoise and modify each noisy coefficients matrix in each scale with predefined initial 3D sparse dictionary. Dark pixels between retinal pigment epithelium and nerve fiber layer that were extracted with graph theory are considered as cystoid spaces. The average dice coefficient for the segmentation of cystoid regions in whole 3D volume and with-in central 3 mm diameter on the MICCAI 2015 OPTIMA Cyst Segmentation Challenge dataset were found to be 0.65 and 0.77, respectively. PMID:27563573

  2. Bone tissue engineering therapeutics: controlled drug delivery in three-dimensional scaffolds

    PubMed Central

    Mouriño, Viviana; Boccaccini, Aldo R.

    2010-01-01

    This paper provides an extensive overview of published studies on the development and applications of three-dimensional bone tissue engineering (TE) scaffolds with potential capability for the controlled delivery of therapeutic drugs. Typical drugs considered include gentamicin and other antibiotics generally used to combat osteomyelitis, as well as anti-inflammatory drugs and bisphosphonates, but delivery of growth factors is not covered in this review. In each case reviewed, special attention has been given to the technology used for controlling the release of the loaded drugs. The possibility of designing multifunctional three-dimensional bone TE scaffolds for the emerging field of bone TE therapeutics is discussed. A detailed summary of drugs included in three-dimensional scaffolds and the several approaches developed to combine bioceramics with various polymeric biomaterials in composites for drug-delivery systems is included. The main results presented in the literature are discussed and the remaining challenges in the field are summarized with suggestions for future research directions. PMID:19864265

  3. Dimensional and temporal controls of three-dimensional cell migration by zyxin and binding partners

    PubMed Central

    Fraley, Stephanie I.; Feng, Yunfeng; Giri, Anjil; Longmore, Gregory D.; Wirtz, Denis

    2015-01-01

    Spontaneous molecular oscillations are ubiquitous in biology. But to our knowledge, periodic cell migratory patterns have not been observed. Here we report the highly regular, periodic migration of cells along rectilinear tracks generated inside three-dimensional matrices, with each excursion encompassing several cell lengths, a phenotype that does not occur on conventional substrates. Short hairpin RNA depletion shows that these one-dimensional oscillations are uniquely controlled by zyxin and binding partners α-actinin and p130Cas, but not vasodilator-stimulated phosphoprotein and cysteine-rich protein 1. Oscillations are recapitulated for cells migrating along one-dimensional micropatterns, but not on two-dimensional compliant substrates. These results indicate that although two-dimensional motility can be well described by speed and persistence, three-dimensional motility requires two additional parameters, the dimensionality of the cell paths in the matrix and the temporal control of cell movements along these paths. These results also suggest that the zyxin/α-actinin/p130Cas module may ensure that motile cells in a three-dimensional matrix explore the largest space possible in minimum time. PMID:22395610

  4. Effectiveness of Mini Implants in Three-Dimensional Control During Retraction - A Clinical Study

    PubMed Central

    Victor, Deepak; Prabhakar, Ramchandra; Karthikeyan, M.K.; Saravanan, R.; Vanathi, P.; Vikram, N. Raj; Reddy, P. Adarsh; Sudeepthi, M.

    2014-01-01

    Introduction: Three-dimensional control throughout the orthodontic treatment is essential for uncompromised results. Mini screws introduced for orthodontic anchorage has given the clinician an option of absolute three dimensional control. The purpose of this study was to compare and measure the vertical control and torque control of incisors and molar during enmass retraction with titanium microimplants and conventional molar anchorage. Material and Methods: Twenty patients were selected with extraction of all first premolars and bonded with 0.022″ slot MBT system. After aligning and leveling, all subjects were placed with 0.019″ X 0.025″ posted SS wire with standardized torquing curve. The 20 subjects were randomly divided into 2 groups consisting of 10 each (Group A & Group B). Group A subjects, implants were placed and Group B formed the control group. Retraction was carried out using NiTi closed coil springs. The assessment of the vertical and torque control of incisors and tipping and vertical control of molars was done by radiographic method using lateral cephalogram taken before and after retraction. Results: The torque control of incisors, P11 value in group A and B indicated no significant difference. The molar tip, P12 value in group A indicated that there was distal tipping of molars while the P12 in group B indicated mesial tipping. On vertical plane P21, P22 and P23 values in Group A indicated that there was intrusion of incisors and molars while value in Group B indicated extrusion of incisors and molars. Conclusion: Three dimensional control is better in the implant group compared to the non implant group. Therefore the implant group definitely has citied advantages over conventional method. PMID:24701541

  5. Three-dimensional motion tracking for high-resolution optical microscopy, in vivo.

    PubMed

    Bakalar, M; Schroeder, J L; Pursley, R; Pohida, T J; Glancy, B; Taylor, J; Chess, D; Kellman, P; Xue, H; Balaban, R S

    2012-06-01

    When conducting optical imaging experiments, in vivo, the signal to noise ratio and effective spatial and temporal resolution is fundamentally limited by physiological motion of the tissue. A three-dimensional (3D) motion tracking scheme, using a multiphoton excitation microscope with a resonant galvanometer, (512 × 512 pixels at 33 frames s(-1)) is described to overcome physiological motion, in vivo. The use of commercially available graphical processing units permitted the rapid 3D cross-correlation of sequential volumes to detect displacements and adjust tissue position to track motions in near real-time. Motion phantom tests maintained micron resolution with displacement velocities of up to 200 μm min(-1), well within the drift observed in many biological tissues under physiologically relevant conditions. In vivo experiments on mouse skeletal muscle using the capillary vasculature with luminal dye as a displacement reference revealed an effective and robust method of tracking tissue motion to enable (1) signal averaging over time without compromising resolution, and (2) tracking of cellular regions during a physiological perturbation.

  6. Dirac and Weyl rings in three-dimensional cold-atom optical lattices

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Zhang, Chuanwei

    2016-06-01

    Recently three-dimensional topological quantum materials with gapless energy spectra have attracted considerable interest in many branches of physics. Besides the celebrated example, Dirac and Weyl points which possess gapless point structures in the underlying energy dispersion, the topologically protected gapless spectrum, can also occur along a ring, named Dirac and Weyl nodal rings. Ultracold atomic gases provide an ideal platform for exploring new topological materials with designed symmetries and dispersion. However, whether Dirac and Weyl rings can exist in the single-particle spectrum of cold atoms remains elusive. Here we propose a realistic model for realizing Dirac and Weyl rings in the single-particle band dispersion of a cold-atom optical lattice. Our scheme is based on a previously experimentally implemented Raman coupling setup for realizing spin-orbit coupling. Without the Zeeman field, the model preserves both pseudo-time-reversal and inversion symmetries, allowing Dirac rings. The Dirac rings split into Weyl rings with a Zeeman field that breaks the pseudo-time-reversal symmetry. We examine the superfluidity of attractive Fermi gases in this model and also find Dirac and Weyl rings in the quasiparticle spectrum.

  7. Three-dimensional reconstructions from optical sections of thick mouse inner ears using confocal microscopy.

    PubMed

    Kopecky, B J; Duncan, J S; Elliott, K L; Fritzsch, B

    2012-12-01

    Three-dimensional (3D) reconstructions of the vertebrate inner ear have provided novel insights into the development of this complex organ. 3D reconstructions enable superior analysis of phenotypic differences between wild type and mutant ears but can result in laborious work when reconstructed from physically sectioned material. Although nondestructive optical sectioning light sheet microscopy may ultimately prove the ideal solution, these technologies are not yet commercially available, or in many instances are not monetarily feasible. Here we introduce a simple technique to image a fluorescently labelled ear at different stages throughout development at high resolution enabling 3D reconstruction of any component of the inner ear using confocal microscopy. We provide a step-by-step manual from tissue preparation to imaging to 3D reconstruction and analysis including a rationale and troubleshooting guide at each step for researchers with different equipment, protocols, and access to resources to successfully incorporate the principles of this method and customize them to their laboratory settings.

  8. The assessment of orthodontic bonding defects: optical coherence tomography followed by three-dimensional reconstruction

    NASA Astrophysics Data System (ADS)

    Rominu, R.; Sinescu, C.; Rominu, M.; Negrutiu, M.; Petrescu, E.; Pop, D.; Podoleanu, A. Gh.

    2011-10-01

    Orthodontic bonding is a simple yet important procedure that can influence the outcome of treatment in case it is performed incorrectly. An orthodontic treatment shadowed by repeated bonding failures can become unduly long and will decrease patient trust and compliance. Optical coherence tomography has been widely used in ophtalmology but is relatively new to dentistry. Using OCT one can detect aerial inclusions within the orthodontic adhesive or even identify incongruence between the bracket base and the tooth surface. The aim of our study was to identify bonding defects and reconstruct them three-dimensionally in order to be able to characterize them more accurately. We bonded 30 sound human permanent teeth with ceramic orthodontic brackets using a no-mix self-curing orthodontic adhesive. Prior to bonding all teeth were stored in tap water at 4°C and then professionally cleaned with rotary brushes and pumice. The samples were processed by the same person and the rotary brushes were changed after every fifth tooth. All interfaces were investigated by means of OCT and 4 defects were found. Subsequently, the defects were reconstructed threedimensionally using an open-source program. By identifying and reconstructing bonding defects we could assess the quality of the bonding procedure. Since bonding tends to be more accurate in vitro where the environmental conditions are close to ideal, it is probable that defects found in vivo be even greater in number, which leads to the conclusion that this type of investigation is potentially valuable.

  9. The characteristics of three-dimensional skin imaging system by full-colored optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Yang, Bor-Wen; Chan, Li-Ming; Wang, Kai-Cheng

    2009-05-01

    In the present cosmetic market, the skin image obtained from a hand-held camera is two-dimensional (2-D). Due to insufficient penetration, only the skin surface can be detected, and thus phenomena in the dermis cannot be observed. To take the place of the conventional 2D camera, a new hand-held imaging system is proposed for three-dimensional (3-D) skin imaging. Featuring non-invasiveness, optical coherence tomography (OCT) has become one of the popular medical imaging techniques. The dermal images shown in OCT-related reports were mainly single-colored because of the use of a monotonic light source. With three original-colored beams applied in OCT, a full-colored image can be derived for dermatology. The penetration depth of the system ranges from 0.43 to 0.78 mm, sufficient for imaging of main tissues in the dermis. Colorful and non-invasive perspectives of deep dermal structure help to advance skin science, dermatology and cosmetology.

  10. Real-time three-dimensional Fourier-domain optical coherence tomography video image guided microsurgeries

    NASA Astrophysics Data System (ADS)

    Kang, Jin U.; Huang, Yong; Zhang, Kang; Ibrahim, Zuhaib; Cha, Jaepyeong; Lee, W. P. Andrew; Brandacher, Gerald; Gehlbach, Peter L.

    2012-08-01

    The authors describe the development of an ultrafast three-dimensional (3D) optical coherence tomography (OCT) imaging system that provides real-time intraoperative video images of the surgical site to assist surgeons during microsurgical procedures. This system is based on a full-range complex conjugate free Fourier-domain OCT (FD-OCT). The system was built in a CPU-GPU heterogeneous computing architecture capable of video OCT image processing. The system displays at a maximum speed of 10 volume/s for an image volume size of 160×80×1024 (X×Y×Z) pixels. We have used this system to visualize and guide two prototypical microsurgical maneuvers: microvascular anastomosis of the rat femoral artery and ultramicrovascular isolation of the retinal arterioles of the bovine retina. Our preliminary experiments using 3D-OCT-guided microvascular anastomosis showed optimal visualization of the rat femoral artery (diameter<0.8 mm), instruments, and suture material. Real-time intraoperative guidance helped facilitate precise suture placement due to optimized views of the vessel wall during anastomosis. Using the bovine retina as a model system, we have performed "ultra microvascular" feasibility studies by guiding handheld surgical micro-instruments to isolate retinal arterioles (diameter˜0.1 mm). Isolation of the microvessels was confirmed by successfully passing a suture beneath the vessel in the 3D imaging environment.

  11. Three-dimensional imaging of the developing mouse female reproductive organs with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Burton, Jason C.; Wang, Shang; Behringer, Richard R.; Larina, Irina V.

    2016-03-01

    Infertility is a known major health concern and is estimated to impact ~15% of couples in the U.S. The majority of failed pregnancies occur before or during implantation of the fertilized embryo into the uterus. Understanding the mechanisms regulating development by studying mouse reproductive organs could significantly contribute to an improved understanding of normal development of reproductive organs and developmental causes of infertility in humans. Towards this goal, we report a three-dimensional (3D) imaging study of the developing mouse reproductive organs (ovary, oviduct, and uterus) using optical coherence tomography (OCT). In our study, OCT was used for 3D imaging of reproductive organs without exogenous contrast agents and provides micro-scale spatial resolution. Experiments were conducted in vitro on mouse reproductive organs ranging from the embryonic day 14.5 to adult stages. Structural features of the ovary, oviduct, and uterus are presented. Additionally, a comparison with traditional histological analysis is illustrated. These results provide a basis for a wide range of infertility studies in mouse models. Through integration with traditional genetic and molecular biology approaches, this imaging method can improve understanding of ovary, oviduct, and uterus development and function, serving to further contribute to our understanding of fertility and infertility.

  12. Live-cell multiplane three-dimensional super-resolution optical fluctuation imaging.

    PubMed

    Geissbuehler, Stefan; Sharipov, Azat; Godinat, Aurélien; Bocchio, Noelia L; Sandoz, Patrick A; Huss, Anja; Jensen, Nickels A; Jakobs, Stefan; Enderlein, Jörg; Gisou van der Goot, F; Dubikovskaya, Elena A; Lasser, Theo; Leutenegger, Marcel

    2014-12-18

    Super-resolution optical fluctuation imaging (SOFI) provides an elegant way of overcoming the diffraction limit in all three spatial dimensions by computing higher-order cumulants of image sequences of blinking fluorophores acquired with a classical widefield microscope. Previously, three-dimensional (3D) SOFI has been demonstrated by sequential imaging of multiple depth positions. Here we introduce a multiplexed imaging scheme for the simultaneous acquisition of multiple focal planes. Using 3D cross-cumulants, we show that the depth sampling can be increased. The simultaneous acquisition of multiple focal planes significantly reduces the acquisition time and thus the photobleaching. We demonstrate multiplane 3D SOFI by imaging fluorescently labelled cells over an imaged volume of up to 65 × 65 × 3.5 μm(3) without depth scanning. In particular, we image the 3D network of mitochondria in fixed C2C12 cells immunostained with Alexa 647 fluorophores and the 3D vimentin structure in living Hela cells expressing the fluorescent protein Dreiklang.

  13. Live-cell multiplane three-dimensional super-resolution optical fluctuation imaging

    NASA Astrophysics Data System (ADS)

    Geissbuehler, Stefan; Sharipov, Azat; Godinat, Aurélien; Bocchio, Noelia L.; Sandoz, Patrick A.; Huss, Anja; Jensen, Nickels A.; Jakobs, Stefan; Enderlein, Jörg; Gisou van der Goot, F.; Dubikovskaya, Elena A.; Lasser, Theo; Leutenegger, Marcel

    2014-12-01

    Super-resolution optical fluctuation imaging (SOFI) provides an elegant way of overcoming the diffraction limit in all three spatial dimensions by computing higher-order cumulants of image sequences of blinking fluorophores acquired with a classical widefield microscope. Previously, three-dimensional (3D) SOFI has been demonstrated by sequential imaging of multiple depth positions. Here we introduce a multiplexed imaging scheme for the simultaneous acquisition of multiple focal planes. Using 3D cross-cumulants, we show that the depth sampling can be increased. The simultaneous acquisition of multiple focal planes significantly reduces the acquisition time and thus the photobleaching. We demonstrate multiplane 3D SOFI by imaging fluorescently labelled cells over an imaged volume of up to 65 × 65 × 3.5 μm3 without depth scanning. In particular, we image the 3D network of mitochondria in fixed C2C12 cells immunostained with Alexa 647 fluorophores and the 3D vimentin structure in living Hela cells expressing the fluorescent protein Dreiklang.

  14. Automated quantitative assessment of three-dimensional bioprinted hydrogel scaffolds using optical coherence tomography

    PubMed Central

    Wang, Ling; Xu, Mingen; Zhang, LieLie; Zhou, QingQing; Luo, Li

    2016-01-01

    Reconstructing and quantitatively assessing the internal architecture of opaque three-dimensional (3D) bioprinted hydrogel scaffolds is difficult but vital to the improvement of 3D bioprinting techniques and to the fabrication of functional engineered tissues. In this study, swept-source optical coherence tomography was applied to acquire high-resolution images of hydrogel scaffolds. Novel 3D gelatin/alginate hydrogel scaffolds with six different representative architectures were fabricated using our 3D bioprinting system. Both the scaffold material networks and the interconnected flow channel networks were reconstructed through volume rendering and binarisation processing to provide a 3D volumetric view. An image analysis algorithm was developed based on the automatic selection of the spatially-isolated region-of–interest. Via this algorithm, the spatially-resolved morphological parameters including pore size, pore shape, strut size, surface area, porosity, and interconnectivity were quantified precisely. Fabrication defects and differences between the designed and as-produced scaffolds were clearly identified in both 2D and 3D; the locations and dimensions of each of the fabrication defects were also defined. It concludes that this method will be a key tool for non-destructive and quantitative characterization, design optimisation and fabrication refinement of 3D bioprinted hydrogel scaffolds. Furthermore, this method enables investigation into the quantitative relationship between scaffold structure and biological outcome. PMID:27231597

  15. Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

    NASA Astrophysics Data System (ADS)

    Gaertner, Maria; Cimalla, Peter; Meissner, Sven; Kuebler, Wolfgang M.; Koch, Edmund

    2012-07-01

    Although several strategies exist for a minimal-invasive treatment of patients with lung failure, the mortality rate of acute respiratory distress syndrome still reaches 30% at minimum. This striking number indicates the necessity of understanding lung dynamics on an alveolar level. To investigate the dynamical behavior on a microscale, we used three-dimensional geometrical and functional imaging to observe tissue parameters including alveolar size and length of embedded elastic fibers during ventilation. We established a combined optical coherence tomography (OCT) and confocal fluorescence microscopy system that is able to monitor the distension of alveolar tissue and elastin fibers simultaneously within three dimensions. The OCT system can laterally resolve a 4.9 μm line pair feature and has an approximately 11 μm full-width-half-maximum axial resolution in air. confocal fluorescence microscopy visualizes molecular properties of the tissue with a resolution of 0.75 μm (laterally), and 5.9 μm (axially) via fluorescence detection of the dye sulforhodamine B specifically binding to elastin. For system evaluation, we used a mouse model in situ to perform lung distension by application of different constant pressure values within the physiological regime. Our method enables the investigation of alveolar dynamics by helping to reveal basic processes emerging during artificial ventilation and breathing.

  16. Improved three-dimensional Fourier domain optical coherence tomography by index matching in alveolar structures

    NASA Astrophysics Data System (ADS)

    Meissner, Sven; Knels, Lilla; Koch, Edmund

    2009-11-01

    Three-dimensional Fourier domain optical coherence tomography (3-D FDOCT) is used to demonstrate that perfusion fixation with a mixture of glutaraldehyde and paraformaldehyde does not alter the geometry of subpleural lung parenchyma in isolated and perfused rabbit lungs. This is confirmed by simultaneous imaging of lung parenchyma with intravital microscopy. To eliminate the diffraction index interfaces between alveolar pockets and walls, we fill the fixed lungs with ethanol by perfusing with gradually increasing concentrations. This bottom-up filling process leaves no remaining air bubbles in the alveolar structures, thus drastically improving the resolution and penetration depth of 3-D FDOCT imaging. We observe an approximately 18% increase in alveolar area after ethanol filling, likely due in large part to elimination of the air/tissue interfaces. 3-D OCT datasets acquired from ethanol-filled lungs allow segmentation of the ethanol-filled structures, which were formerly air-filled, and 3-D reconstruction of larger areas of subpleural alveolar structures. Our innovative process of filling the lungs with ethanol postperfusion fixation thus enables more accurate quantification of alveolar geometries, a critical component of modeling lung function.

  17. Real-time three-dimensional Fourier-domain optical coherence tomography video image guided microsurgeries

    PubMed Central

    Huang, Yong; Zhang, Kang; Ibrahim, Zuhaib; Cha, Jaepyeong; Lee, W. P. Andrew; Brandacher, Gerald; Gehlbach, Peter L.

    2012-01-01

    Abstract. The authors describe the development of an ultrafast three-dimensional (3D) optical coherence tomography (OCT) imaging system that provides real-time intraoperative video images of the surgical site to assist surgeons during microsurgical procedures. This system is based on a full-range complex conjugate free Fourier-domain OCT (FD-OCT). The system was built in a CPU-GPU heterogeneous computing architecture capable of video OCT image processing. The system displays at a maximum speed of 10  volume/s for an image volume size of 160×80×1024 (X×Y×Z) pixels. We have used this system to visualize and guide two prototypical microsurgical maneuvers: microvascular anastomosis of the rat femoral artery and ultramicrovascular isolation of the retinal arterioles of the bovine retina. Our preliminary experiments using 3D-OCT-guided microvascular anastomosis showed optimal visualization of the rat femoral artery (diameter<0.8  mm), instruments, and suture material. Real-time intraoperative guidance helped facilitate precise suture placement due to optimized views of the vessel wall during anastomosis. Using the bovine retina as a model system, we have performed “ultra microvascular” feasibility studies by guiding handheld surgical micro-instruments to isolate retinal arterioles (diameter∼0.1  mm). Isolation of the microvessels was confirmed by successfully passing a suture beneath the vessel in the 3D imaging environment. PMID:23224164

  18. Hadron Optics in Three-Dimensional Invariant Coordinate Space from Deeply Virtual Compton Scattering

    SciTech Connect

    Brodsky, S J; Chakrabarti, D; Harindranath, A; Mukherjee, A; Vary, J P

    2006-11-10

    The Fourier transform of the deeply virtual Compton scattering amplitude (DVCS) with respect to the skewness parameter {zeta} = Q{sup 2}/2p {center_dot} q can be used to provide an image of the target hadron in the boost-invariant variable {sigma}, the coordinate conjugate to light-front time {tau} = t + z/c. As an illustration, we construct a consistent covariant model of the DVCS amplitude and its associated generalized parton distributions using the quantum fluctuations of a fermion state at one loop in QED, thus providing a representation of the light-front wavefunctions of a lepton in {sigma} space. A consistent model for hadronic amplitudes can then be obtained by differentiating the light-front wavefunctions with respect to the bound-state mass. The resulting DVCS helicity amplitudes are evaluated as a function of {sigma} and the impact parameter {rvec b}{sub {perpendicular}}, thus providing a light-front ''photograph'' of the target hadron in a frame-independent three-dimensional light-front coordinate space. We find that in the models studied, the Fourier transform of the DVCS amplitudes exhibit diffraction patterns. The results are analogous to the diffractive scattering of a wave in optics where the distribution in {sigma} measures the physical size of the scattering center in a one-dimensional system.

  19. High-resolution imaging diagnosis of human fetal membrane by three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ren, Hugang; Avila, Cecilia; Kaplan, Cynthia; Pan, Yingtian

    2011-11-01

    Microscopic chorionic pseudocyst (MCP) arising in the chorion leave of the human fetal membrane (FM) is a clinical precursor for preeclampsia which may progress to fatal medical conditions (e.g., abortion) if left untreated. To examine the utility of three-dimensional (3D) optical coherence tomography (OCT) for noninvasive delineation of the morphology of human fetal membranes and early clinical detection of MCP, 60 human FM specimens were acquired from 10 different subjects undergoing term cesarean delivery for an ex vivo feasibility study. Our results showed that OCT was able to identify the four-layer architectures of human FMs consisting of high-scattering decidua vera (DV, average thickness dDV ~ 92+/-38 μm), low-scattering chorion and trophoblast (CT, dCT ~ 150+/-67 μm), high-scattering subepithelial amnion (A, dA ~ 95+/-36 μm), and low-scattering epithelium (E, dE ~ 29+/-8 μm). Importantly, 3D OCT was able to instantaneously detect MCPs (low scattering due to edema, fluid buildup, vasodilatation) and track (staging) their thicknesses dMCP ranging from 24 to 615 μm. It was also shown that high-frequency ultrasound was able to compliment OCT for detecting more advanced thicker MCPs (e.g., dMCP>615 μm) because of its increased imaging depth.

  20. Three-dimensional motion tracking for high-resolution optical microscopy, in vivo.

    PubMed

    Bakalar, M; Schroeder, J L; Pursley, R; Pohida, T J; Glancy, B; Taylor, J; Chess, D; Kellman, P; Xue, H; Balaban, R S

    2012-06-01

    When conducting optical imaging experiments, in vivo, the signal to noise ratio and effective spatial and temporal resolution is fundamentally limited by physiological motion of the tissue. A three-dimensional (3D) motion tracking scheme, using a multiphoton excitation microscope with a resonant galvanometer, (512 × 512 pixels at 33 frames s(-1)) is described to overcome physiological motion, in vivo. The use of commercially available graphical processing units permitted the rapid 3D cross-correlation of sequential volumes to detect displacements and adjust tissue position to track motions in near real-time. Motion phantom tests maintained micron resolution with displacement velocities of up to 200 μm min(-1), well within the drift observed in many biological tissues under physiologically relevant conditions. In vivo experiments on mouse skeletal muscle using the capillary vasculature with luminal dye as a displacement reference revealed an effective and robust method of tracking tissue motion to enable (1) signal averaging over time without compromising resolution, and (2) tracking of cellular regions during a physiological perturbation. PMID:22582797

  1. Three-dimensional surface microfluidics enabled by spatiotemporal control of elastic fluidic interface.

    PubMed

    Hong, Lingfei; Pan, Tingrui

    2010-12-01

    As an emerging alternative to the conventional counterpart, surface microfluidics incorporates both intrinsic resistive solid-liquid and elastic frictionless gas-liquid interfaces, leading to unique flow-pressure characteristics. Furthermore, the open-surface microfluidic platforms can be fabricated on a monolithic substrate with high wettability contrast by the previously reported one-step lithographic process of a photosensitive superhydrophobic nanocomposite material, which permits flexible fluidic operations and direct surface modifications. In the paper, we first present three-dimensional microfluidic manipulations utilizing the unconventional gas-liquid interfaces of surface microfluidics, outlined by the micropatterned wetting boundaries (also known as the triple lines). In contrast to the primary linear (resistive) nature of the conventional closed-channel microfluidics, the distinct elastic interface of surface microfluidics enables remarkable three-dimensional (deformable) and time-dependent (capacitive) operations of the flow. Specifically, spatiotemporal dependence of microflow patterns on the planar fluidic surfaces has been theoretically analyzed and experimentally characterized. Utilizing the unconventional interface-enabled flow-pressure relationship, novel surface fluidic operations, including microflow regulation and flow-controlled switching, have been demonstrated and fully investigated. Furthermore, three-dimensional surface microfluidic networks together with analog-to-digital stereo-flow activations have been established, in which miniature capillary bridges form fluidic connections between two independent surface microfluidic circuits.

  2. Three-dimensional optic axis determination using variable-incidence-angle polarization-optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ugryumova, Nadezhda; Gangnus, Sergei V.; Matcher, Stephen J.

    2006-08-01

    Polarization optical coherence tomography (PSOCT) is a powerful technique to nondestructively map the retardance and fast-axis orientation of birefringent biological tissues. Previous studies have concentrated on the case where the optic axis lies on the plane of the surface. We describe a method to determine the polar angle of the optic axis of a uniaxial birefringent tissue by making PSOCT measurements with a number of incident illumination directions. The method is validated on equine flexor tendon, yielding a variability of 4% for the true birefringence and 3% for the polar angle. We use the method to map the polar angle of fibers in the transitional region of equine cartilage.

  3. Innovative optical scanning technique and device for three-dimensional full-scale measurement of wind-turbine blades

    NASA Astrophysics Data System (ADS)

    Fu, Ho-Ling; Fan, Kuang-Chao; Huang, Yu-Jan; Hu, Ming-Kai

    2014-12-01

    A full-scale three-dimensional profile measurement system with an innovative optical setup for measuring the geometric shape of large wind-turbine blades in high accuracy is developed. A normal full-scale wind blade geometry measurement system can be very expensive. The presented system is low cost, but it can yield a high accuracy for geometric dimensions by error compensation from its measured data. It consists of a low cost long linear stage driven by a direct current motor with linear scale feedback for position and velocity control, and two line-scan optical heads mounted on opposite sides. The line image of the sectional shape profile can be captured by two charge-coupled devices. By scanning the optical head throughout the full length of the blade, the image of the whole profile can be collected. The shape parameters of the wind-turbine blades can thus be determined. A special effort has been employed to improve the straightness and positioning accuracy of the linear stage by error compensation. With system calibration of the stage and the cameras, experimental results show high accuracy of the developed system. This low-cost optical system is expected to measure any full-scale wind blade profile up to several meters in length.

  4. Laboratory-size three-dimensional water-window x-ray microscope with Wolter type I mirror optics

    NASA Astrophysics Data System (ADS)

    Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

    2016-01-01

    We constructed a laboratory-size three-dimensional water-window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques. It consists of an electron-impact x-ray source emitting oxygen Kα x-rays, Wolter type I grazing incidence mirror optics, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit better than 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm-scale three-dimensional fine structures were resolved.

  5. Development of a compression molding process for three-dimensional tailored free-form glass optics.

    PubMed

    Yi, Allen Y; Huang, Chunning; Klocke, Fritz; Brecher, Christian; Pongs, Guido; Winterschladen, Markus; Demmer, Axel; Lange, Sven; Bergs, Thomas; Merz, Michael; Niehaus, Frank

    2006-09-01

    Because of the limitation of manufacturing capability, free-form glass optics cannot be produced in a large volume using traditional processes such as grinding, lapping, and polishing. Very recently compression molding of glass optics became a viable manufacturing process for the high-volume production of precision glass optical components. An ultraprecision diamond-turning machine retrofitted with a fast tool servo was used to fabricate a free-form optical mold on a nickel-plated surface. A nonuniform rational B-spline trajectory generator was developed to calculate the computer numerical control machine tool path. A specially formulated glass with low transition temperature (Tg) was used, since the nickel alloy mold cannot withstand the high temperatures required for regular optical glasses. We describe the details of this process, from optical surface geometry, mold making, molding experiment, to lens measurement.

  6. Automated volumetric stent analysis of in-vivo intracoronary optical coherence tomography three-dimensional datasets

    NASA Astrophysics Data System (ADS)

    Ughi, Giovanni J.; Adriaenssens, Tom; Onsea, Kevin; Dubois, Christophe; Coosemans, Mark; Sinnaeve, Peter; Desmet, Walter; D'hooge, Jan

    2011-06-01

    Intra-vascular Optical Coherence Tomography (IV-OCT) is an appropriate imaging modality for the evaluation of stent struts apposition and coverage in the coronary arteries. Most often, image analysis is performed by a time-consuming manual contour tracing process. Recently, we proposed an algorithm for fully automated lumen morphology and individual stent struts apposition/coverage quantification. In this manuscript further developments allowing for automatic segmentation of the stent contour are presented. As such, quantification of in-stent area, malapposition cross-sectional area (i.e. the area representing the space from the stent surface to the vessel wall) and coverage cross-sectional area (i.e. the area of the tissue covering the stent surface) are automatically obtained. Volumetric measurements of malapposition and coverage are then achieved through the analysis of equally-spaced consecutive IV-OCT cross-sectional images. In addition, uncovered and malapposed struts are automatically clustered through consecutive slices according to their three-dimensional spatial position. Finally, properties of each cluster (e.g. malapposition/coverage volumes and struts spatial location and distribution) are quantified allowing for a volumetric analysis of the implanted device. Validation of the algorithm was obtained taking as a reference manual measurements performed by an expert cardiologist. 102 in-vivo images, taken at random from 8 different patients, were both automatically and manually analyzed quantifying lumen and stent area. High Pearson's correlation coefficients (Rarea = 0.99) and Bland-Altman statistics, showing no significant bias and good limits of agreement, proved that the presented algorithm provides a robust and fast tool to automatically estimate apposition and coverage of stent through an entire in-vivo IV-OCT pullback. Such a tool will be important for the integration of this technology in clinical routine and large clinical trials.

  7. Automatic three-dimensional registration of intravascular optical coherence tomography images

    NASA Astrophysics Data System (ADS)

    Ughi, Giovanni J.; Adriaenssens, Tom; Larsson, Matilda; Dubois, Christophe; Sinnaeve, Peter R.; Coosemans, Mark; Desmet, Walter; D'hooge, Jan

    2012-02-01

    Intravascular optical coherence tomography (IV-OCT) is a catheter-based high-resolution imaging technique able to visualize the inner wall of the coronary arteries and implanted devices in vivo with an axial resolution below 20 μm. IV-OCT is being used in several clinical trials aiming to quantify the vessel response to stent implantation over time. However, stent analysis is currently performed manually and corresponding images taken at different time points are matched through a very labor-intensive and subjective procedure. We present an automated method for the spatial registration of IV-OCT datasets. Stent struts are segmented through consecutive images and three-dimensional models of the stents are created for both datasets to be registered. The two models are initially roughly registered through an automatic initialization procedure and an iterative closest point algorithm is subsequently applied for a more precise registration. To correct for nonuniform rotational distortions (NURDs) and other potential acquisition artifacts, the registration is consecutively refined on a local level. The algorithm was first validated by using an in vitro experimental setup based on a polyvinyl-alcohol gel tubular phantom. Subsequently, an in vivo validation was obtained by exploiting stable vessel landmarks. The mean registration error in vitro was quantified to be 0.14 mm in the longitudinal axis and 7.3-deg mean rotation error. In vivo validation resulted in 0.23 mm in the longitudinal axis and 10.1-deg rotation error. These results indicate that the proposed methodology can be used for automatic registration of in vivo IV-OCT datasets. Such a tool will be indispensable for larger studies on vessel healing pathophysiology and reaction to stent implantation. As such, it will be valuable in testing the performance of new generations of intracoronary devices and new therapeutic drugs.

  8. Practical fully three-dimensional reconstruction algorithms for diffuse optical tomography.

    PubMed

    Biswas, Samir Kumar; Kanhirodan, Rajan; Vasu, Ram Mohan; Roy, Debasish

    2012-06-01

    We have developed an efficient fully three-dimensional (3D) reconstruction algorithm for diffuse optical tomography (DOT). The 3D DOT, a severely ill-posed problem, is tackled through a pseudodynamic (PD) approach wherein an ordinary differential equation representing the evolution of the solution on pseudotime is integrated that bypasses an explicit inversion of the associated, ill-conditioned system matrix. One of the most computationally expensive parts of the iterative DOT algorithm, the reevaluation of the Jacobian in each of the iterations, is avoided by using the adjoint-Broyden update formula to provide low rank updates to the Jacobian. In addition, wherever feasible, we have also made the algorithm efficient by integrating along the quadratic path provided by the perturbation equation containing the Hessian. These algorithms are then proven by reconstruction, using simulated and experimental data and verifying the PD results with those from the popular Gauss-Newton scheme. The major findings of this work are as follows: (i) the PD reconstructions are comparatively artifact free, providing superior absorption coefficient maps in terms of quantitative accuracy and contrast recovery; (ii) the scaling of computation time with the dimension of the measurement set is much less steep with the Jacobian update formula in place than without it; and (iii) an increase in the data dimension, even though it renders the reconstruction problem less ill conditioned and thus provides relatively artifact-free reconstructions, does not necessarily provide better contrast property recovery. For the latter, one should also take care to uniformly distribute the measurement points, avoiding regions close to the source so that the relative strength of the derivatives for measurements away from the source does not become insignificant.

  9. Two-step design method for highly compact three-dimensional freeform optical system for LED surface light source.

    PubMed

    Mao, Xianglong; Li, Hongtao; Han, Yanjun; Luo, Yi

    2014-10-20

    Designing an illumination system for a surface light source with a strict compactness requirement is quite challenging, especially for the general three-dimensional (3D) case. In accordance with the two key features of an expected illumination distribution, i.e., a well-controlled boundary and a precise illumination pattern, a two-step design method is proposed in this paper for highly compact 3D freeform illumination systems. In the first step, a target shape scaling strategy is combined with an iterative feedback modification algorithm to generate an optimized freeform optical system with a well-controlled boundary of the target distribution. In the second step, a set of selected radii of the system obtained in the first step are optimized to further improve the illuminating quality within the target region. The method is quite flexible and effective to design highly compact optical systems with almost no restriction on the shape of the desired target field. As examples, three highly compact freeform lenses with ratio of center height h of the lens and the maximum dimension D of the source ≤ 2.5:1 are designed for LED surface light sources to form a uniform illumination distribution on a rectangular, a cross-shaped and a complex cross pierced target plane respectively. High light control efficiency of η > 0.7 as well as low relative standard illumination deviation of RSD < 0.07 is obtained simultaneously for all the three design examples. PMID:25607306

  10. Three-dimensional correction of conduction velocity in the embryonic heart using integrated optical mapping and optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ma, Pei; Wang, Yves T.; Gu, Shi; Watanabe, Michiko; Jenkins, Michael W.; Rollins, Andrew M.

    2014-07-01

    Optical mapping (OM) of cardiac electrical activity conventionally collects information from a three-dimensional (3-D) surface as a two-dimensional (2-D) projection map. When applied to measurements of the embryonic heart, this method ignores the substantial and complex curvature of the heart surface, resulting in significant errors when calculating conduction velocity, an important electrophysiological parameter. Optical coherence tomography (OCT) is capable of imaging the 3-D structure of the embryonic heart and accurately characterizing the surface topology. We demonstrate an integrated OCT/OM imaging system capable of simultaneous conduction mapping and 3-D structural imaging. From these multimodal data, we obtained 3-D activation maps and corrected conduction velocity maps of early embryonic quail hearts. 3-D correction eliminates underestimation bias in 2-D conduction velocity measurements, therefore enabling more accurate measurements with less experimental variability. The integrated system will also open the door to correlate the structure and electrophysiology, thereby improving our understanding of heart development.

  11. Three-dimensional imaging of normal skin and nonmelanoma skin cancer with cellular resolution using Gabor domain optical coherence microscopy.

    PubMed

    Lee, Kye-Sung; Zhao, Huimin; Ibrahim, Sherrif F; Meemon, Natthani; Khoudeir, Laura; Rolland, Jannick P

    2012-12-01

    We investigate morphological differences in three-dimensional (3-D) images with cellular resolution between nonmelanoma skin cancer and normal skin using Gabor domain optical coherence microscopy. As a result, we show for the first time cellular optical coherence images of 3-D features differentiating cancerous skin from normal skin. In addition, in vivo volumetric images of normal skin from different anatomic locations are shown and compared.

  12. Optical phase cloaking of 700 nm light waves in the far field by a three-dimensional carpet cloak.

    PubMed

    Ergin, Tolga; Fischer, Joachim; Wegener, Martin

    2011-10-21

    Transformation optics is a design tool that connects the geometry of space and propagation of light. Invisibility cloaking is a corresponding benchmark example. Recent experiments at optical frequencies have demonstrated cloaking for the light amplitude only. In this Letter, we demonstrate far-field cloaking of the light phase by interferometric microscope-imaging experiments on the previously introduced three-dimensional carpet cloak at 700 nm wavelength and for arbitrary polarization of light.

  13. Adaptive femtosecond control using feedback from three-dimensional momentum images

    NASA Astrophysics Data System (ADS)

    Wells, E.

    2011-05-01

    Shaping ultrafast laser pulses using adaptive feedback is a proven technique for manipulating dynamics in molecular systems with no readily apparent control mechanism. Commonly employed feedback signals include fluorescence or ion yield, which may not uniquely identify the final state. Raw velocity map images, which contain a two-dimensional representation of the full three-dimensional photofragment momentum vector, are a more specific feedback source. The raw images, however, are limited by an azimuthal ambiguity which is usually removed in offline processing. By implementing a rapid inversion procedure based upon the onion-peeling technique, we are able to incorporate three-dimensional momentum information directly into the adaptive control loop. This method enables more targeted control experiments. Two examples are used to demonstrate the utility of this feedback. First, double ionization of CO produces C+ and O+ fragments ejected both perpendicular and parallel to the laser polarization with kinetic energy release of ~6 eV. Both suppression and enhancement of the perpendicular transitions relative to the parallel transitions are demonstrated. Second, double ionization of acetylene can lead to both HCCH2+ and HHCC2+ isomers. We select between these outcomes using the angular information contained in the CH+ and CH2+images. Supported by National Science Foundation award PHY-0969687 and the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Science, Office of Science, US Department of Energy.

  14. Coordination control of quadrotor VTOL aircraft in three-dimensional space

    NASA Astrophysics Data System (ADS)

    Do, K. D.

    2015-03-01

    This paper presents a constructive design of distributed coordination controllers for a group of N quadrotor vertical take-off and landing (VTOL) aircraft in three-dimensional space. A combination of Euler angles and unit-quaternion for the attitude representation of the aircraft is used to result in an effective control design, and to reduce singularities in the aircraft's dynamics. The coordination control design is based on a new bounded control design technique for second-order systems and new pairwise collision avoidance functions. The pairwise collision functions are functions of both relative positions and relative velocities between the aircraft instead of only their relative positions as in the literature. To overcome the inherent underactuation of the aircraft, the roll and pitch angles of the aircraft are considered as immediate controls. Simulations illustrate the results.

  15. Three-dimensional patterning and morphological control of porous nanomaterials by gray-scale direct imprinting

    PubMed Central

    Ryckman, Judson D.; Jiao, Yang; Weiss, Sharon M.

    2013-01-01

    We present a method for direct three-dimensional (3D) patterning of porous nanomaterials through the application of a premastered and reusable gray-scale stamp. Four classes of 3D nanostructures are demonstrated for the first time in porous media: gradient profiles, digital patterns, curves and lens shapes, and sharp features including v-grooves, nano-pits, and ‘cookie-cutter’ particles. Further, we demonstrate this technique enables morphological tuning and direct tailoring of nanomaterial properties, including porosity, average pore size, dielectric constant, and plasmonic response. This work opens a rapid and low-cost route for fabricating novel nanostructures and devices utilizing porous nanomaterials, with promising applications spanning diffractive and plasmonic sensing, holography, micro- and transformation optics, and drug delivery and imaging. PMID:23518798

  16. Three-dimensional patterning and morphological control of porous nanomaterials by gray-scale direct imprinting.

    PubMed

    Ryckman, Judson D; Jiao, Yang; Weiss, Sharon M

    2013-01-01

    We present a method for direct three-dimensional (3D) patterning of porous nanomaterials through the application of a premastered and reusable gray-scale stamp. Four classes of 3D nanostructures are demonstrated for the first time in porous media: gradient profiles, digital patterns, curves and lens shapes, and sharp features including v-grooves, nano-pits, and 'cookie-cutter' particles. Further, we demonstrate this technique enables morphological tuning and direct tailoring of nanomaterial properties, including porosity, average pore size, dielectric constant, and plasmonic response. This work opens a rapid and low-cost route for fabricating novel nanostructures and devices utilizing porous nanomaterials, with promising applications spanning diffractive and plasmonic sensing, holography, micro- and transformation optics, and drug delivery and imaging. PMID:23518798

  17. Optical distortion correction in optical coherence tomography for quantitative ocular anterior segment by three-dimensional imaging.

    PubMed

    Ortiz, Sergio; Siedlecki, Damian; Grulkowski, Ireneusz; Remon, Laura; Pascual, Daniel; Wojtkowski, Maciej; Marcos, Susana

    2010-02-01

    A method for three-dimensional 3-D optical distortion (refraction) correction on anterior segment Optical Coherence Tomography (OCT) images has been developed. The method consists of 3-D ray tracing through the different surfaces, following denoising, segmentation of the surfaces, Delaunay representation of the surfaces, and application of fan distortion correction. The correction has been applied theoretically to realistic computer eye models, and experimentally to OCT images of: an artificial eye with a Polymethyl Methacrylate (PMMA) cornea and an intraocular lens (IOL), an enucleated porcine eye, and a human eye in vivo obtained from two OCT laboratory set-ups (time domain and spectral). Data are analyzed in terms of surface radii of curvature and asphericity. Comparisons are established between the reference values for the surfaces (nominal values in the computer model; non-contact profilometric measurements for the artificial eye; Scheimpflug imaging for the real eyes in vivo and vitro). The results from the OCT data were analyzed following the conventional approach of dividing the optical path by the refractive index, after application of 2-D optical correction, and 3-D optical correction (in all cases after fan distortion correction). The application of 3-D optical distortion correction increased significantly both the accuracy of the radius of curvature estimates and particularly asphericity of the surfaces, with respect to conventional methods of OCT image analysis. We found that the discrepancies of the radii of curvature estimates from 3-D optical distortion corrected OCT images are less than 1% with respect to nominal values. Optical distortion correction in 3-D is critical for quantitative analysis of OCT anterior segment imaging, and allows accurate topography of the internal surfaces of the eye. PMID:20174107

  18. Optical distortion correction in optical coherence tomography for quantitative ocular anterior segment by three-dimensional imaging.

    PubMed

    Ortiz, Sergio; Siedlecki, Damian; Grulkowski, Ireneusz; Remon, Laura; Pascual, Daniel; Wojtkowski, Maciej; Marcos, Susana

    2010-02-01

    A method for three-dimensional 3-D optical distortion (refraction) correction on anterior segment Optical Coherence Tomography (OCT) images has been developed. The method consists of 3-D ray tracing through the different surfaces, following denoising, segmentation of the surfaces, Delaunay representation of the surfaces, and application of fan distortion correction. The correction has been applied theoretically to realistic computer eye models, and experimentally to OCT images of: an artificial eye with a Polymethyl Methacrylate (PMMA) cornea and an intraocular lens (IOL), an enucleated porcine eye, and a human eye in vivo obtained from two OCT laboratory set-ups (time domain and spectral). Data are analyzed in terms of surface radii of curvature and asphericity. Comparisons are established between the reference values for the surfaces (nominal values in the computer model; non-contact profilometric measurements for the artificial eye; Scheimpflug imaging for the real eyes in vivo and vitro). The results from the OCT data were analyzed following the conventional approach of dividing the optical path by the refractive index, after application of 2-D optical correction, and 3-D optical correction (in all cases after fan distortion correction). The application of 3-D optical distortion correction increased significantly both the accuracy of the radius of curvature estimates and particularly asphericity of the surfaces, with respect to conventional methods of OCT image analysis. We found that the discrepancies of the radii of curvature estimates from 3-D optical distortion corrected OCT images are less than 1% with respect to nominal values. Optical distortion correction in 3-D is critical for quantitative analysis of OCT anterior segment imaging, and allows accurate topography of the internal surfaces of the eye.

  19. Three-dimensional structure and multistable optical switching of triple-twisted particle-like excitations in anisotropic fluids

    NASA Astrophysics Data System (ADS)

    Smalyukh, Ivan I.; Lansac, Yves; Clark, Noel A.; Trivedi, Rahul P.

    2010-02-01

    Control of structures in soft materials with long-range order forms the basis for applications such as displays, liquid-crystal biosensors, tunable lenses, distributed feedback lasers, muscle-like actuators and beam-steering devices. Bistable, tristable and multistable switching of well-defined structures of molecular alignment is of special interest for all of these applications. Here we describe the facile optical creation and multistable switching of localized configurations in the molecular orientation field of a chiral nematic anisotropic fluid. These localized chiro-elastic particle-like excitations-dubbed `triple-twist torons'-are generated by vortex laser beams and embed the localized three-dimensional (3D) twist into a uniform background. Confocal polarizing microscopy and computer simulations reveal their equilibrium internal structures, manifesting both skyrmion-like and Hopf fibration features. Robust generation of torons at predetermined locations combined with both optical and electrical reversible switching can lead to new ways of multistable structuring of complex photonic architectures in soft materials.

  20. Mechanism of drag reduction on a three-dimensional model vehicle using a passive control device

    NASA Astrophysics Data System (ADS)

    Yi, Wook; Sagong, Woong; Choi, Haecheon

    2007-11-01

    It has been well known that the boat-tail device reduces drag on a three-dimensional vehicle. However, its detailed mechanism is not clearly known yet. To understand this mechanism, we conduct an experiment for flow over a three-dimensional model vehicle in ground proximity. We consider various lengths (l/H = 0.1 ˜0.5) and slant angles (θ=0^o ˜40^o) of the boat tail, and conduct velocity measurements near the boat tail and oil visualizations on the boat-tail surface. We find that the slant angle is an important parameter for drag reduction. The maximum drag reduction occurs at θ=12.5^o, 15^o and 15^o for l/H = 0.1, 0.3 and 0.5, respectively, and the amounts of maximum drag reduction are 20, 41 and 45%. For the case of l/H = 0.3, separation starts to occur from θ= 6^o at the leading edge of the boat tail. This separated flow reattaches on the boat-tail surface and forms a small secondary separation bubble, which provides strong near-wall momentum and delays main separation down to the trailing edge of boat tail. The size of secondary separation bubble increases with increasing θ. At θ>16^o, main separation occurs at the leading edge of boat tail, and drag increases from the minimum value and reaches that of no control at large θ's.

  1. Controlled synthesis of hyper-branched inorganic nanocrystals withrich three-dimensional structures

    SciTech Connect

    Kanaras, Antonios G.; Sonnichsen, Carsten; Liu, Haitao; Alivisatos, A. Paul

    2005-07-27

    Studies of crystal growth kinetics are tightly integrated with advances in the creation of new nanoscale inorganic building blocks and their functional assemblies 1-11. Recent examples include the development of semiconductor nanorods which have potential uses in solar cells 12-17, and the discovery of a light driven process to create noble metal particles with sharp corners that can be used in plasmonics 18,19. In the course of studying basic crystal growth kinetics we developed a process for preparing branched semiconductor nanocrystals such as tetrapods and inorganic dendrimers of precisely controlled generation 20,21. Here we report the discovery of a crystal growth kinetics regime in which a new class of hyper-branched nanocrystals are formed. The shapes range from 'thorny balls', to tree-like ramified structures, to delicate 'spider net'-like particles. These intricate shapes depend crucially on a delicate balance of branching and extension. The multitudes of resulting shapes recall the diverse shapes of snowflakes 22.The three dimensional nature of the branch points here, however, lead to even more complex arrangements than the two dimensionally branched structures observed in ice. These hyper-branched particles not only extend the available three-dimensional shapes in nanoparticle synthesis ,but also provide a tool to study growth kinetics by carefully observing and modeling particle morphology.

  2. Numerical study of three-dimensional separation and flow control at a wing/body junction

    NASA Technical Reports Server (NTRS)

    Ash, Robert L.; Lakshmanan, Balakrishnan

    1989-01-01

    The problem of three-dimensional separation and flow control at a wing/body junction has been investigated numerically using a three-dimensional Navier-Stokes code. The numerical code employs an algebraic grid generation technique for generating the grid for unmodified junction and an elliptic grid generation technique for filleted fin junction. The results for laminar flow past a blunt fin/flat plate junction demonstrate that after grid refinement, the computations agree with experiment and reveal a strong dependency of the number of vortices at the junction on Mach number and Reynolds number. The numerical results for pressure distribution, particle paths and limiting streamlines for turbulent flow past a swept fin show a decrease in the peak pressure and in the extent of the separated flow region compared to the laminar case. The results for a filleted juncture indicate that the streamline patterns lose much of their vortical character with proper filleting. Fillets with a radius of three and one-half times the fin leading edge diameter or two times the incoming boundary layer thickness, significantly weaken the usual necklace interaction vortex for the Mach number and Reynolds number considered in the present study.

  3. Soft-Lithographical Fabrication of Three-dimensional Photonic Crystals in the Optical Regime

    SciTech Connect

    Lee, Jae-Hwang

    2006-01-01

    This dissertation describes several projects to realize low-cost and high-quality three-dimensional (3D) microfabrication using non-photolithographic techniques for layer-by-layer photonic crystals. Low-cost, efficient 3D microfabrication is a demanding technique not only for 3D photonic crystals but also for all other scientific areas, since it may create new functionalities beyond the limit of planar structures. However, a novel 3D microfabrication technique for photonic crystals implies the development of a complete set of sub-techniques for basic layer-by-layer stacking, inter-layer alignment, and material conversion. One of the conventional soft lithographic techniques, called microtransfer molding (μTM), was developed by the Whitesides group in 1996. Although μTM technique potentially has a number of advantages to overcome the limit of conventional photolithographic techniques in building up 3D microstructures, it has not been studied intensively after its demonstration. This is mainly because of technical challenges in the nature of layer-by-layer fabrication, such as the demand of very high yield in fabrication. After two years of study on conventional μTM, We have developed an advanced microtransfer molding technique, called two-polymer microtransfer molding (2P-μTM) that shows an extremely high yield in layer-by-layer microfabrication sufficient to produce highly layered microstructures. The use of two different photo-curable prepolymers, a filler and an adhesive, allows for fabrication of layered microstructures without thin films between layers. The capabilities of 2P-μTM are demonstrated by the fabrication of a wide-area 12-layer microstructure with high structural fidelity. Second, we also had to develop an alignment technique. We studied the 1st-order diffracted moire fringes of transparent multilayered structures comprised of irregularly deformed periodic patterns. By a comparison study of the diffracted moire fringe pattern and detailed

  4. UAV formation control design with obstacle avoidance in dynamic three-dimensional environment.

    PubMed

    Chang, Kai; Xia, Yuanqing; Huang, Kaoli

    2016-01-01

    This paper considers the artificial potential field method combined with rotational vectors for a general problem of multi-unmanned aerial vehicle (UAV) systems tracking a moving target in dynamic three-dimensional environment. An attractive potential field is generated between the leader and the target. It drives the leader to track the target based on the relative position of them. The other UAVs in the formation are controlled to follow the leader by the attractive control force. The repulsive force affects among the UAVs to avoid collisions and distribute the UAVs evenly on the spherical surface whose center is the leader-UAV. Specific orders or positions of the UAVs are not required. The trajectories of avoidance obstacle can be obtained through two kinds of potential field with rotation vectors. Every UAV can choose the optimal trajectory to avoid the obstacle and reconfigure the formation after passing the obstacle. Simulations study on UAV are presented to demonstrate the effectiveness of proposed method.

  5. Depth-tunable three-dimensional display with interactive light field control

    NASA Astrophysics Data System (ADS)

    Xie, Songlin; Wang, Peng; Sang, Xinzhu; Li, Chenyu; Dou, Wenhua; Xiao, Liquan

    2016-07-01

    A software-defined depth-tunable three-dimensional (3D) display with interactive 3D depth control is presented. With the proposed post-processing system, the disparity of the multi-view media can be freely adjusted. Benefiting from a wealth of information inherently contains in dense multi-view images captured with parallel arrangement camera array, the 3D light field is built and the light field structure is controlled to adjust the disparity without additional acquired depth information since the light field structure itself contains depth information. A statistical analysis based on the least square is carried out to extract the depth information inherently exists in the light field structure and the accurate depth information can be used to re-parameterize light fields for the autostereoscopic display, and a smooth motion parallax can be guaranteed. Experimental results show that the system is convenient and effective to adjust the 3D scene performance in the 3D display.

  6. Statistics Analysis of the Uncertainties in Cloud Optical Depth Retrievals Caused by Three-Dimensional Radiative Effects

    NASA Technical Reports Server (NTRS)

    Varnai, Tamas; Marshak, Alexander

    2000-01-01

    This paper presents a simple approach to estimate the uncertainties that arise in satellite retrievals of cloud optical depth when the retrievals use one-dimensional radiative transfer theory for heterogeneous clouds that have variations in all three dimensions. For the first time, preliminary error bounds are set to estimate the uncertainty of cloud optical depth retrievals. These estimates can help us better understand the nature of uncertainties that three-dimensional effects can introduce into retrievals of this important product of the MODIS instrument. The probability distribution of resulting retrieval errors is examined through theoretical simulations of shortwave cloud reflection for a wide variety of cloud fields. The results are used to illustrate how retrieval uncertainties change with observable and known parameters, such as solar elevation or cloud brightness. Furthermore, the results indicate that a tendency observed in an earlier study, clouds appearing thicker for oblique sun, is indeed caused by three-dimensional radiative effects.

  7. Processing to determine optical parameters of atherosclerotic disease from phantom and clinical intravascular optical coherence tomography three-dimensional pullbacks.

    PubMed

    Shalev, Ronny; Gargesha, Madhusudhana; Prabhu, David; Tanaka, Kentaro; Rollins, Andrew M; Lamouche, Guy; Bisaillon, Charles-Etienne; Bezerra, Hiram G; Ray, Soumya; Wilson, David L

    2016-04-01

    Analysis of intravascular optical coherence tomography (IVOCT) data has potential for real-time in vivo plaque classification. We developed a processing pipeline on a three-dimensional local region of support for estimation of optical properties of atherosclerotic plaques from coronary artery, IVOCT pullbacks. Using realistic coronary artery disease phantoms, we determined insignificant differences in mean and standard deviation estimates between our pullback analyses and more conventional processing of stationary acquisitions with frame averaging. There was no effect of tissue depth or oblique imaging on pullback parameter estimates. The method's performance was assessed in comparison with observer-defined standards using clinical pullback data. Values (calcium [Formula: see text], lipid [Formula: see text], and fibrous [Formula: see text]) were consistent with previous measurements obtained by other means. Using optical parameters ([Formula: see text], [Formula: see text], [Formula: see text]), we achieved feature space separation of plaque types and classification accuracy of [Formula: see text]. Despite the rapid [Formula: see text] motion and varying incidence angle in pullbacks, the proposed computational pipeline appears to work as well as a more standard "stationary" approach. PMID:27213167

  8. Spatially controlled simultaneous patterning of multiple growth factors in three-dimensional hydrogels

    NASA Astrophysics Data System (ADS)

    Wylie, Ryan G.; Ahsan, Shoeb; Aizawa, Yukie; Maxwell, Karen L.; Morshead, Cindi M.; Shoichet, Molly S.

    2011-10-01

    Three-dimensional (3D) protein-patterned scaffolds provide a more biomimetic environment for cell culture than traditional two-dimensional surfaces, but simultaneous 3D protein patterning has proved difficult. We developed a method to spatially control the immobilization of different growth factors in distinct volumes in 3D hydrogels, and to specifically guide differentiation of stem/progenitor cells therein. Stem-cell differentiation factors sonic hedgehog (SHH) and ciliary neurotrophic factor (CNTF) were simultaneously immobilized using orthogonal physical binding pairs, barnase-barstar and streptavidin-biotin, respectively. Barnase and streptavidin were sequentially immobilized using two-photon chemistry for subsequent concurrent complexation with fusion proteins barstar-SHH and biotin-CNTF, resulting in bioactive 3D patterned hydrogels. The technique should be broadly applicable to the patterning of a wide range of proteins.

  9. Large-range control of the microstructures and properties of three-dimensional porous graphene.

    PubMed

    Xie, Xiao; Zhou, Yilong; Bi, Hengchang; Yin, Kuibo; Wan, Shu; Sun, Litao

    2013-01-01

    Graphene-based three-dimensional porous macrostructures are believed of great importance in various applications, e.g. supercapacitors, photovoltaic cells, sensors and high-efficiency sorbents. However, to precisely control the microstructures and properties of this material to meet different application requirements in industrial practice remains challenging. We herein propose a facile and highly effective strategy for large-range tailoring the porous architecture and its properties by a modified freeze casting process. The pore sizes and wall thicknesses of the porous graphene can be gradually tuned by 80 times (from 10 to 800 μm) and 4000 times (from 20 nm to 80 μm), respectively. The property experiences the changing from hydrophilic to hydrophobic, with the Young's Modulus varying by 15 times. The fundamental principle of the porous microstructure evolution is discussed in detail. Our results demonstrate a very convenient and general protocol to finely tailor the structure and further benefit the various applications of porous graphene.

  10. Tissue growth into three-dimensional composite scaffolds with controlled micro-features and nanotopographical surfaces.

    PubMed

    Tamjid, Elnaz; Simchi, Arash; Dunlop, John W C; Fratzl, Peter; Bagheri, Reza; Vossoughi, Manouchehr

    2013-10-01

    Controlling topographic features at all length scales is of great importance for the interaction of cells with tissue regenerative materials. We utilized an indirect three-dimensional printing method to fabricate polymeric scaffolds with pre-defined and controlled external and internal architecture that had an interconnected structure with macro- (400-500 μm) and micro- (∼25 μm) porosity. Polycaprolactone (PCL) was used as model system to study the kinetics of tissue growth within porous scaffolds. The surface of the scaffolds was decorated with TiO2 and bioactive glass (BG) nanoparticles to the better match to nanoarchitecture of extracellular matrix (ECM). Micrometric BG particles were also used to reveal the effect of particle size on the cell behavior. Observation of tissue growth and enzyme activity on two-dimensional (2D) films and three-dimensional (3D) scaffolds showed effects of nanoparticle inclusion and of surface curvature on the cellular adhesion, proliferation, and kinetics of preosteoblastic cells (MC3T3-E1) tissue growth into the pore channels. It was found that the presence of nanoparticles in the substrate impaired cellular adhesion and proliferation in 3D structures. Evaluation of alkaline phosphate activity showed that the presence of the hard particles affects differentiation of the cells on 2D films. Notwithstanding, the effect of particles on cell differentiation was not as strong as that seen by the curvature of the substrate. We observed different effects of nanofeatures on 2D structures with those of 3D scaffolds, which influence the cell proliferation and differentiation for non-load-bearing applications in bone regenerative medicine. PMID:23463703

  11. Longitudinal spin separation of light and its performance in three-dimensionally controllable spin-dependent focal shift.

    PubMed

    Liu, Sheng; Li, Peng; Zhang, Yi; Gan, Xuetao; Wang, Meirong; Zhao, Jianlin

    2016-01-01

    Spin Hall effect of light, which is normally explored as a transverse spin-dependent separation of a light beam, has attracted enormous research interests. However, it seems there is no indication for the existence of the longitudinal spin separation of light. In this paper, we propose and experimentally realize the spin separation along the propagation direction by modulating the Pancharatnam-Berry (PB) phase. Due to the spin-dependent divergence and convergence determined by the PB phase, a focused Gaussian beam could split into two opposite spin states, and focuses at different distances, representing the longitudinal spin separation. By combining this longitudinal spin separation with the transverse one, we experimentally achieve the controllable spin-dependent focal shift in three dimensional space. This work provides new insight on steering the spin photons, and is expected to explore novel applications of optical trapping, manipulating, and micromachining with higher degree of freedom. PMID:26882995

  12. Longitudinal spin separation of light and its performance in three-dimensionally controllable spin-dependent focal shift

    PubMed Central

    Liu, Sheng; Li, Peng; Zhang, Yi; Gan, Xuetao; Wang, Meirong; Zhao, Jianlin

    2016-01-01

    Spin Hall effect of light, which is normally explored as a transverse spin-dependent separation of a light beam, has attracted enormous research interests. However, it seems there is no indication for the existence of the longitudinal spin separation of light. In this paper, we propose and experimentally realize the spin separation along the propagation direction by modulating the Pancharatnam-Berry (PB) phase. Due to the spin-dependent divergence and convergence determined by the PB phase, a focused Gaussian beam could split into two opposite spin states, and focuses at different distances, representing the longitudinal spin separation. By combining this longitudinal spin separation with the transverse one, we experimentally achieve the controllable spin-dependent focal shift in three dimensional space. This work provides new insight on steering the spin photons, and is expected to explore novel applications of optical trapping, manipulating, and micromachining with higher degree of freedom. PMID:26882995

  13. Three-dimensional closed-loop control of self-propelled microjets

    NASA Astrophysics Data System (ADS)

    Khalil, Islam S. M.; Magdanz, Veronika; Sanchez, Samuel; Schmidt, Oliver G.; Misra, Sarthak

    2013-10-01

    We demonstrate precise closed-loop control of microjets under the influence of the magnetic fields in three-dimensional (3D) space. For this purpose, we design a magnetic-based control system that directs the field lines towards reference positions. Microjets align along the controlled field lines using the magnetic torque exerted on their magnetic dipole, and move towards the reference positions using their self-propulsion force. We demonstrate the controlled motion of microjets in 3D space, and show that their propulsion force allows them to overcome vertical forces, such as buoyancy forces, interaction forces with oxygen bubbles, and vertical flow. The closed-loop control localizes the microjets within a spherical region of convergence with an average diameter of 406±220 μm, whereas the self-propulsion force allows them to swim at an average speed of 222±74 μm/s within the horizontal plane. Furthermore, we observe that the controlled microjets dive downward and swim upward towards reference positions at average speeds of 232±40 μm/s and 316±81 μm/s, respectively.

  14. Three-dimensional surface profiling and optical characterization of liquid microlens using a Shack-Hartmann wave front sensor.

    PubMed

    Li, Chenhui; Hall, Gunnsteinn; Zeng, Xuefeng; Zhu, Difeng; Eliceiri, Kevin; Jiang, Hongrui

    2011-04-25

    We demonstrate three-dimensional (3D) surface profiling of the water-oil interface in a tunable liquid microlens using a Shack-Hartmann wave front sensor. The principles and the optical setup for achieving 3D surface measurements are presented and a hydrogel-actuated liquid lens was measured at different focal lengths. The 3D surface profiles are then used to study the optical properties of the liquid lens. Our method of 3D surface profiling could foster the improvement of liquid lens design and fabrication, including surface treatment and aberration reduction.

  15. Three-dimensional controlled growth of monodisperse sub-50 nm heterogeneous nanocrystals

    PubMed Central

    Liu, Deming; Xu, Xiaoxue; Du, Yi; Qin, Xian; Zhang, Yuhai; Ma, Chenshuo; Wen, Shihui; Ren, Wei; Goldys, Ewa M.; Piper, James A.; Dou, Shixue; Liu, Xiaogang; Jin, Dayong

    2016-01-01

    The ultimate frontier in nanomaterials engineering is to realize their composition control with atomic scale precision to enable fabrication of nanoparticles with desirable size, shape and surface properties. Such control becomes even more useful when growing hybrid nanocrystals designed to integrate multiple functionalities. Here we report achieving such degree of control in a family of rare-earth-doped nanomaterials. We experimentally verify the co-existence and different roles of oleate anions (OA−) and molecules (OAH) in the crystal formation. We identify that the control over the ratio of OA− to OAH can be used to directionally inhibit, promote or etch the crystallographic facets of the nanoparticles. This control enables selective grafting of shells with complex morphologies grown over nanocrystal cores, thus allowing the fabrication of a diverse library of monodisperse sub-50 nm nanoparticles. With such programmable additive and subtractive engineering a variety of three-dimensional shapes can be implemented using a bottom–up scalable approach. PMID:26743184

  16. Three-dimensional controlled growth of monodisperse sub-50 nm heterogeneous nanocrystals.

    PubMed

    Liu, Deming; Xu, Xiaoxue; Du, Yi; Qin, Xian; Zhang, Yuhai; Ma, Chenshuo; Wen, Shihui; Ren, Wei; Goldys, Ewa M; Piper, James A; Dou, Shixue; Liu, Xiaogang; Jin, Dayong

    2016-01-01

    The ultimate frontier in nanomaterials engineering is to realize their composition control with atomic scale precision to enable fabrication of nanoparticles with desirable size, shape and surface properties. Such control becomes even more useful when growing hybrid nanocrystals designed to integrate multiple functionalities. Here we report achieving such degree of control in a family of rare-earth-doped nanomaterials. We experimentally verify the co-existence and different roles of oleate anions (OA(-)) and molecules (OAH) in the crystal formation. We identify that the control over the ratio of OA(-) to OAH can be used to directionally inhibit, promote or etch the crystallographic facets of the nanoparticles. This control enables selective grafting of shells with complex morphologies grown over nanocrystal cores, thus allowing the fabrication of a diverse library of monodisperse sub-50 nm nanoparticles. With such programmable additive and subtractive engineering a variety of three-dimensional shapes can be implemented using a bottom-up scalable approach. PMID:26743184

  17. A boundary element approach to optimization of active noise control sources on three-dimensional structures

    NASA Technical Reports Server (NTRS)

    Cunefare, K. A.; Koopmann, G. H.

    1991-01-01

    This paper presents the theoretical development of an approach to active noise control (ANC) applicable to three-dimensional radiators. The active noise control technique, termed ANC Optimization Analysis, is based on minimizing the total radiated power by adding secondary acoustic sources on the primary noise source. ANC Optimization Analysis determines the optimum magnitude and phase at which to drive the secondary control sources in order to achieve the best possible reduction in the total radiated power from the noise source/control source combination. For example, ANC Optimization Analysis predicts a 20 dB reduction in the total power radiated from a sphere of radius at a dimensionless wavenumber ka of 0.125, for a single control source representing 2.5 percent of the total area of the sphere. ANC Optimization Analysis is based on a boundary element formulation of the Helmholtz Integral Equation, and thus, the optimization analysis applies to a single frequency, while multiple frequencies can be treated through repeated analyses.

  18. Fractal frequency spectrum in laser resonators and three-dimensional geometric topology of optical coherent waves

    NASA Astrophysics Data System (ADS)

    Tung, J. C.; Tuan, P. H.; Liang, H. C.; Huang, K. F.; Chen, Y. F.

    2016-08-01

    We theoretically verify that the symmetry breaking in spherical resonators can result in a fractal frequency spectrum that is full of numerous new accidental degeneracies to cluster around the unperturbed degenerate cavity. We further experimentally discover that the fractal frequency spectrum excellently reflects the intimate connection between the emission power and the degenerate mode numbers. It is observed that the wave distributions of lasing modes at the accidental degeneracies are strongly concentrated on three-dimensional (3D) geometric topology. Considering the overlapping effect, the wave representation of the coherent states is analytically derived to manifest the observed 3D geometric surfaces.

  19. Optical response of three-dimensional photonic lattices: Solutions of inhomogeneous Maxwell's equations and their applications

    NASA Astrophysics Data System (ADS)

    Sakoda, Kazuaki; Ohtaka, Kazuo

    1996-08-01

    We have formulated a Green's function method for the radiation field in an arbitrary three-dimensional photonic lattice to deal with the source term of an extrinsic polarization field Pex(r,t). It is shown that the induced field is expressed as a superposition of Pex(r,t) itself and the photonic-band eigenmodes of a nonzero frequency. The longitudinal eigenmodes of zero frequency, which are important for the closure relation of photonic bands, is shown to contribute nothing to the propagating electric field. We have applied this method to the treatments of sum frequency generation, dipole radiation, and free induction decay.

  20. Simultaneous three-dimensional optical coherence tomography and intravital microscopy for imaging subpleural pulmonary alveoli in isolated rabbit lungs

    NASA Astrophysics Data System (ADS)

    Meissner, Sven; Knels, Lilla; Krueger, Alexander; Koch, Thea; Koch, Edmund

    2009-09-01

    There is a growing interest in analyzing lung mechanics at the level of the alveoli in order to understand stress-related pathogenesis and possibly avoid ventilator associated lung injury. Emerging quantitative models to simulate fluid mechanics and the associated stresses and strains on delicate alveolar walls require realistic quantitative input on alveolar geometry and its dynamics during ventilation. Here, three-dimensional optical coherence tomography (OCT) and conventional intravital microscopy are joined in one setup to investigate the geometric changes of subpleural alveoli during stepwise pressure increase and release in an isolated and perfused rabbit lung model. We describe good qualitative agreement and quantitative correlation between the OCT data and video micrographs. Our main finding is the inflation and deflation of individual alveoli with noticeable hysteresis. Importantly, this three-dimensional geometry data can be extracted and converted into input data for numerical simulations.

  1. Three-dimensional imaging of eye surface pathologies and contact lens fit with high resolution spectral optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Wojtkowski, M.; Kałużny, B.; Szkulmowska, A.; Bajraszewski, T.; Szkulmowski, M.; Targowski, P.; Kowalczyk, A.

    2007-02-01

    Purpose: To show potential of Spectral Optical Coherence Tomography system for high resolution, cross-sectional and three-dimensional imaging of eye surface pathologies. Methods: High-speed spectral OCT prototype instrument with 4.5 μm axial resolution was designed and constructed for clinical use. Measurements of anterior segment of human eye have been performed in ophthalmology clinic on 86 patients suffering various eye surface disorders including corneal dystrophies, corneal scars, conjunctival folds, keratoconus, bullus keratopathy, filtration blebs and other post-operative changes. Additionally, examinations of contact lens fit on 97 healthy corneas have been performed up to date. Results: High quality, high resolution cross-sectional images and three-dimensional reconstructions of cornea, conjunctiva and sclera of pathologic eyes together with examples of numerical analysis including segmentation of fluid in filtration blebs, scars and deposits are shown. Quantitative analysis of contact lens fit is demonstrated.

  2. Image formation of holographic three-dimensional display based on spatial light modulator in paraxial optical systems

    NASA Astrophysics Data System (ADS)

    Li, Junchang; Lin, Yu-Chih; Tu, Han-Yen; Gui, Jinbin; Li, Chongguang; Lou, Yuli; Cheng, Chau-Jern

    2015-10-01

    This work describes the image formation and properties of holographic three-dimensional (3-D) display based on spatial light modulators (SLMs) combined with optical imaging systems. Existing pixelated SLMs with periodic mesh structures affect the holographic reconstruction and display properties. According to a holographic 3-D display architecture based on SLM in paraxial optical systems, this study applied the ray matrix optics and scalar diffraction theory to regard the light wave emitting from the holographic plane to the image plane as an optical system composed of four matrix elements. The image quality and depth of field (DOF) of the holographic 3-D display system are investigated, and the relationship between the impulse response and the matrix elements of the holographic imaging system is derived. In addition, the imaging properties and DOF are explored and verified through optical experimentation.

  3. X-ray guided three-dimensional diffuse optical tomography: in vivo study of osteoarthritis in the finger joints

    NASA Astrophysics Data System (ADS)

    Zhang, Qizhi; Yuan, Zhen; Sobel, Eric; Jiang, Huabei

    2007-02-01

    Osteoarthritis (OA), characterized by the damage of the articular cartilage, is the most common joint problem worldwide. In the effort of developing new clinical tools with the potential to alter the natural history of OA, near-infrared diffuse optical tomography (DOT) has received much attention due to its unique advantages. For optical imaging in highly heterogeneous media such as the finger joints, prior information could improve the quality of optical imaging. We report a hybrid imaging system for early detection of OA in the finger joints by imposing the geometry information obtained by X-ray on three-dimensional near-infrared DOT. X-ray tomosynthesis was employed to recover the three-dimensional structure of the two bones based on 16 X-ray projections generated with a mini C-arm system at different directions within a range of 180 degrees. The interface was carefully designed to guarantee an accurate co-registration of the optical and x-ray modalities. The prior structural information of bones was incorporated into our multi-modality imaging reconstruction algorithm to enhance the recovery of the optical properties of joint tissues. Several healthy and OA finger joints were examined. The initial clinical results showed that this hybrid imaging system had the ability to provide much enhanced image resolution and contrast than DOT alone for OA detection.

  4. 360-degree three-dimensional flat panel display using holographic optical elements

    NASA Astrophysics Data System (ADS)

    Yabu, Hirofumi; Takeuchi, Yusuke; Yoshimoto, Kayo; Takahashi, Hideya; Yamada, Kenji

    2015-03-01

    We proposed the 360-degree 3D display system which is composed of a flat panel display, a light control film, and holographic optical element (HOE). The HOE is a diffraction grating which is made by holography technique. HOE lens can be produced on the thin polygonal glass plate. The light control film and HOE lenses are used to control the direction of light from the flat panel display in our system. The size of proposed system depends on the size of the flat panel display is because other parts of proposed system are thin and placed on the screen of the flat panel display. HOE lenses and a light control film are used to control lights from multiple pixels of a flat panel display to multiple viewpoints. To display large 3D images and to increase viewpoints, we divided parallax images into striped images and distributed them on the display for multiple viewpoints. Therefore, observers can see the large 3D image around the system. To verify the effectiveness of the proposed system, we made the experimental system. To verify the effectiveness of the proposed system, we constructed the part of the proposed system. The experimental system is composed of the liquid crystal display (LCD), prototype HOE lenses, and light control films. We confirmed that experimental system can display two images to different viewpoints. This paper describes the configuration of the proposed system, and also describes the experimental result.

  5. Three-dimensional optical lines fabricated onto substrate for on-board interconnection

    NASA Astrophysics Data System (ADS)

    Matsubara, Takahiro; Oda, Keiko; Watanabe, Keiichiro; Maetani, Maraki; Tanaka, Kaori; Tanahashi, Shigeo

    2009-02-01

    Optical lines using polymer materials fabricated on an organic substrate with metal lines and pads are proposed to realize fully optical interconnections among high performance LSIs. This optical line enable transmit high speed optical signals not only on a plane surface but to vertical direction. It has following four particular portions; (1) Curved parallel optical waveguide; (2) 45 degree reflection mirror; (3) Optical via hole with coaxial structure; (4) Optical joint between package and board. The optical line characterized by transmission loss and passed through eye diagram, and good optical signal transmission is confirmed to really use for optical interconnection between LSIs. Then on-board optical signal transmission is demonstrated by that VCSEL and PIN-PD are assembled using flip-chip technology on a circuit board with other electric devices of driving circuit, and also package-to-board optical joint are demonstrated by passing through solder reflow process.

  6. Shape-Controlled Synthesis of Hybrid Nanomaterials via Three-Dimensional Hydrodynamic Focusing

    PubMed Central

    2015-01-01

    Shape-controlled synthesis of nanomaterials through a simple, continuous, and low-cost method is essential to nanomaterials research toward practical applications. Hydrodynamic focusing, with its advantages of simplicity, low-cost, and precise control over reaction conditions, has been used for nanomaterial synthesis. While most studies have focused on improving the uniformity and size control, few have addressed the potential of tuning the shape of the synthesized nanomaterials. Here we demonstrate a facile method to synthesize hybrid materials by three-dimensional hydrodynamic focusing (3D-HF). While keeping the flow rates of the reagents constant and changing only the flow rate of the buffer solution, the molar ratio of two reactants (i.e., tetrathiafulvalene (TTF) and HAuCl4) within the reaction zone varies. The synthesized TTF–Au hybrid materials possess very different and predictable morphologies. The reaction conditions at different buffer flow rates are studied through computational simulation, and the formation mechanisms of different structures are discussed. This simple one-step method to achieve continuous shape-tunable synthesis highlights the potential of 3D-HF in nanomaterials research. PMID:25268035

  7. Three-dimensional graphics simulator for testing mine machine computer-controlled algorithms -- phase 1 development

    SciTech Connect

    Ambrose, D.H. )

    1993-01-01

    Using three-dimensional (3-D) graphics computing to evaluate new technologies for computer-assisted mining systems illustrates how these visual techniques can redefine the way researchers look at raw scientific data. The US Bureau of Mines is using 3-D graphics computing to obtain cheaply, easily, and quickly information about the operation and design of current and proposed mechanical coal and metal-nonmetal mining systems. Bureau engineers developed a graphics simulator for a continuous miner that enables a realistic test for experimental software that controls the functions of a machine. Some of the specific simulated functions of the continuous miner are machine motion, appendage motion, machine position, and machine sensors. The simulator uses data files generated in the laboratory or mine using a computer-assisted mining machine. The data file contains information from a laser-based guidance system and a data acquisition system that records all control commands given to a computer-assisted mining machine. This report documents the first phase in developing the simulator and discusses simulator requirements, features of the initial simulator, and several examples of its application. During this endeavor, Bureau engineers discovered and appreciated the simulator's potential to assist their investigations of machine controls and navigation systems.

  8. Three-dimensional light distribution near the focus of a tightly focused beam of few-cycle optical pulses

    SciTech Connect

    Romallosa, Kristine Marie; Bantang, Johnrob; Saloma, Caesar

    2003-09-01

    Via the Richards-Wolf vector diffraction theory, we analyze the three-dimensional intensity distribution of the focal volume that is produced by a strongly focused 750-nm beam of ultrafast, Gaussian-shaped optical pulses (10{sup -9} s{>=} pulse width {tau}{>=}1 fs=10{sup -15} s). Knowledge of the three-dimensional distribution near focus is essential in determining the diffraction-limited resolution of an optical microscope. The optical spectrum of a short pulse is characterized by side frequencies about the carrier frequency. The effect of spectral broadening on the focused intensity distribution is evaluated via the Linfoot's criteria of fidelity, structural content, and correlation quality and with reference to a 750-nm cw focused beam. Different values are considered for {tau} and numerical aperture of the focusing lens (0.1{<=}X{sub NA}{<=}1.2). At X{sub NA}=0.8, rapid deterioration of the focused intensity distribution is observed at {tau}=1.2 fs. This happens because a 750-nm optical pulse with {tau}=1.2 fs has an associated coherence length of 359.7 nm which is less than the Nyquist sampling interval of 375 nm that is required to sample 750 nm sinusoid without loss of information. The ill-effects of spectral broadening is weaker in two-photon excitation microscope than in its single-photon counterpart for the same focusing lens and light source.

  9. Cell volume control at a surface for three-dimensional grid generation packages

    NASA Technical Reports Server (NTRS)

    Alter, Stephen J.; Weilmuenster, Kenneth J.

    1992-01-01

    An alternate method of calculating the cell size for orthogonality control in the solution of Poisson's 3D space equations is presented. The method provides the capability to enforce a better initial guess for the grid distribution required for boundary layer resolution. This grid point distribution is accomplished by enforcing grid spacing from a grid block boundary where orthogonality is required. The actual grid spacing or cell size for that boundary is determined by the two or four adjacent boundaries in the grid block definition, which are two dimensional grids. These two dimensional grids are in turn defined by the user using insight into the flow field and boundary layer characteristics. The adjoining boundaries are extended using a multifunctional blending scheme, with user control of the blending and interpolating functions to be used. This grid generation procedure results in an enhanced computational fluid dynamics calculation by allowing a quicker resolution of the configuration's boundary layer and flow field and by limiting the number of grid re-adaptations. The cell size specification calculation was applied to a variety of configurations ranging from axisymmetric to complex three-dimensional configurations. Representative grids are shown for the Space Shuttle and the Langley Lifting Body (HL-20).

  10. Three Dimensional Solution of Pneumatic Active Control of Forebody Vortex Asymmetry

    NASA Technical Reports Server (NTRS)

    Kandil, Osama A.; SharafEl-Din, Hazem H.; Liu, C. H.

    1995-01-01

    Pneumatic active control of asymmetric vortical flows around a slender pointed forebody is investigated using the three dimensional solution for the compressible thin-layer Navier-Stokes equation. The computational applications cover the normal and tangential injection control of asymmetric flows around a 5 degree semi-apex angle cone at a 40 degree angle of attack, 1.4 freestream Mach number and 6 x 10(exp 6) freestream Reynolds number (based on the cone length). The effective tangential angle range of 67.5 approaches minus 67.5 degrees is used for both normal and tangential ports of injection. The effective axial length of injection is varied from 0.03 to 0.05. The computational solver uses the implicit, upwind, flux difference splitting finite volume scheme, and the grid consists of 161 x 55 x 65 points in the wrap around, normal and axial directions, respectively. The results show that tangential injection is more effective than normal injection.

  11. UAV formation control design with obstacle avoidance in dynamic three-dimensional environment.

    PubMed

    Chang, Kai; Xia, Yuanqing; Huang, Kaoli

    2016-01-01

    This paper considers the artificial potential field method combined with rotational vectors for a general problem of multi-unmanned aerial vehicle (UAV) systems tracking a moving target in dynamic three-dimensional environment. An attractive potential field is generated between the leader and the target. It drives the leader to track the target based on the relative position of them. The other UAVs in the formation are controlled to follow the leader by the attractive control force. The repulsive force affects among the UAVs to avoid collisions and distribute the UAVs evenly on the spherical surface whose center is the leader-UAV. Specific orders or positions of the UAVs are not required. The trajectories of avoidance obstacle can be obtained through two kinds of potential field with rotation vectors. Every UAV can choose the optimal trajectory to avoid the obstacle and reconfigure the formation after passing the obstacle. Simulations study on UAV are presented to demonstrate the effectiveness of proposed method. PMID:27478741

  12. Three-dimensional cavity cooling and trapping in an optical lattice

    SciTech Connect

    Murr, K.; Nussmann, S.; Puppe, T.; Hijlkema, M.; Weber, B.; Webster, S. C.; Kuhn, A.; Rempe, G.

    2006-06-15

    A robust scheme for trapping and cooling atoms is described. It combines a deep dipole-trap which localizes the atom in the center of a cavity with a laser directly exciting the atom. In that way one obtains three-dimensional cooling while the atom is dipole-trapped. In particular, we identify a cooling force along the large spatial modulations of the trap. A feature of this setup, with respect to a dipole trap alone, is that all cooling forces keep a constant amplitude if the trap depth is increased simultaneously with the intensity of the probe laser. No strong coupling is required, which makes such a technique experimentally attractive. Several analytical expressions for the cooling forces and heating rates are derived and interpreted by analogy to ordinary laser cooling.

  13. Resolving three-dimensional shape of sub-50 nm wide lines with nanometer-scale sensitivity using conventional optical microscopes

    NASA Astrophysics Data System (ADS)

    Attota, Ravikiran; Dixson, Ronald G.

    2014-07-01

    We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 4-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30 nm-40 nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22 nm (k = 2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast, and ideally suited for high volume nanomanufacturing process monitoring.

  14. Modeling, Control and Simulation of Three-Dimensional Robotic Systems with Applications to Biped Locomotion.

    NASA Astrophysics Data System (ADS)

    Zheng, Yuan-Fang

    A three-dimensional, five link biped system is established. Newton-Euler state space formulation is employed to derive the equations of the system. The constraint forces involved in the equations can be eliminated by projection onto a smaller state space system for deriving advanced control laws. A model-referenced adaptive control scheme is developed to control the system. Digital computer simulations of point to point movement are carried out to show that the model-referenced adaptive control increases the dynamic range and speeds up the response of the system in comparison with linear and nonlinear feedback control. Further, the implementation of the controller is simpler. Impact effects of biped contact with the environment are modeled and studied. The instant velocity change at the moment of impact is derived as a function of the biped state and contact speed. The effects of impact on the state, as well as constraints are studied in biped landing on heels and toes simultaneously or on toes first. Rate and nonlinear position feedback are employed for stability of the biped after the impact. The complex structure of the foot is properly modeled. A spring and dashpot pair is suggested to represent the action of plantar fascia during the impact. This action prevents the arch of the foot from collapsing. A mathematical model of the skeletal muscle is discussed. A direct relationship between the stimulus rate and the active state is established. A piecewise linear relation between the length of the contractile element and the isometric force is considered. Hill's characteristic equation is maintained for determining the actual output force during different shortening velocities. A physical threshold model is proposed for recruitment which encompasses the size principle, its manifestations and exceptions to the size principle. Finally the role of spindle feedback in stability of the model is demonstrated by study of a pair of muscles.

  15. Three-Dimensional Self Assembly of Semiconducting Colloidal Nanocrystals: From Fundamental Forces to Collective Optical Properties.

    PubMed

    Abécassis, Benjamin

    2016-03-01

    Self-assembly of colloidal nanoparticles into higher order superstructures is becoming an important topic in current research in nanoscience. More and more research efforts are being dedicated to the controlled processing of nanoparticle dispersions to yield complex architectures from these simple building blocks. This is due to the fact that collective effects can emerge from an assembly of organized nanoparticles. Semiconducting colloidal nanocrystals such as quantum dots are promising materials for a wide range of applications in optoelectronic photovoltaics. The fundamental interactions that dictate the self-assembly of semiconducting colloidal nanocrystals in apolar solvents are reviewed with a focus on 3D structures and basic shapes (spheres, rods, and platelets). Emergent collective properties and the effect of the self-assembly on the optical properties of the particles are also discussed.

  16. Performance of a three dimensional transformation-optical-flattened Lüneburg lens.

    PubMed

    Driscoll, Tom; Lipworth, Guy; Hunt, Jack; Landy, Nathan; Kundtz, Nathan; Basov, Dimitri N; Smith, David R

    2012-06-01

    We demonstrate both the beam-forming and imaging capabilities of an X-band (8-12 GHz) operational Lüneburg lens, one side of which has been flattened via a coordinate transformation optimized using quasi-conformal transformation optics (QCTO) procedures. Our experimental investigation includes benchmark performance comparisons between the QCTO Lüneburg lens and a commensurate conventional Lüneburg lens. The QCTO Lüneburg lens is made from a metamaterial comprised of inexpensive plastic and fiberglass, and manufactured using fast and versatile numerically controlled water-jet machining. Looking forward towards the future and advanced TO designs, we discuss inevitable design trade-offs between affordable scalable manufacturing and rigorous adherence to the full TO solution, as well as possible paths to mitigate performance degradation in realizable designs. PMID:22714354

  17. Formation of Spatially and Geometrically Controlled Three-Dimensional Tissues in Soft Gels by Sacrificial Micromolding

    PubMed Central

    Cerchiari, Alec; Garbe, James C.; Todhunter, Michael E.; Jee, Noel Y.; Pinney, James R.; LaBarge, Mark A.

    2015-01-01

    Patterned three-dimensional (3D) cell culture models aim to more accurately represent the in vivo architecture of a tissue for the purposes of testing drugs, studying multicellular biology, or engineering functional tissues. However, patterning 3D multicellular structures within very soft hydrogels (<500 Pa) that mimic the physicochemical environment of many tissues remains a challenge for existing methods. To overcome this challenge, we use a Sacrificial Micromolding technique to temporarily form spatially and geometrically defined 3D cell aggregates in degradable scaffolds before transferring and culturing them in a reconstituted extracellular matrix. Herein, we demonstrate that Sacrificial Micromolding (1) promotes cyst formation and proper polarization of established epithelial cell lines, (2) allows reconstitution of heterotypic cell–cell interactions in multicomponent epithelia, and (3) can be used to control the lumenization-state of epithelial cysts as a function of tissue size. In addition, we discuss the potential of Sacrificial Micromolding as a cell-patterning tool for future studies. PMID:25351430

  18. Three-dimensional controlled-source electromagnetic and magnetotelluric joint inversion

    SciTech Connect

    Commer, M.; Newman, G.A.

    2009-02-15

    The growing use of the controlled-source electromagnetic method (CSEM) and magnetotellurics (MT) for exploration applications has been driving the development of data acquisition technologies, and three-dimensional (3-D) modeling and imaging techniques. However, targeting increasingly complex geological environments also further enhances the problems inherent in large-scale inversion, such as non-uniqueness and resolution issues. In this paper, we report on two techniques to mitigate these problems. We use 3-D joint CSEM and MT inversion to improve the model resolution. To avoid the suppression of the resolution capacities of one data type, and thus to balance the use of inherent, and ideally complementary information content, different data reweighting schemes are proposed. Further, a hybrid model parameterization approach is presented, where traditional cell-based model parameters are used simultaneously within a parametric inversion. The idea is to limit the non-uniqueness problem, typical for 3-D imaging problems, in order to allow for a more focusing inversion. The methods are demonstrated using synthetic data generated from models with a strong practical relevance.

  19. Matrix mechanics and fluid shear stress control stem cells fate in three dimensional microenvironment.

    PubMed

    Chen, Guobao; Lv, Yonggang; Guo, Pan; Lin, Chongwen; Zhang, Xiaomei; Yang, Li; Xu, Zhiling

    2013-07-01

    Stem cells have the ability to self-renew and to differentiate into multiple mature cell types during early life and growth. Stem cells adhesion, proliferation, migration and differentiation are affected by biochemical, mechanical and physical surface properties of the surrounding matrix in which stem cells reside and stem cells can sensitively feel and respond to the microenvironment of this matrix. More and more researches have proven that three dimensional (3D) culture can reduce the gap between cell culture and physiological environment where cells always live in vivo. This review summarized recent findings on the studies of matrix mechanics that control stem cells (primarily mesenchymal stem cells (MSCs)) fate in 3D environment, including matrix stiffness and extracellular matrix (ECM) stiffness. Considering the exchange of oxygen and nutrients in 3D culture, the effect of fluid shear stress (FSS) on fate decision of stem cells was also discussed in detail. Further, the difference of MSCs response to matrix stiffness between two dimensional (2D) and 3D conditions was compared. Finally, the mechanism of mechanotransduction of stem cells activated by matrix mechanics and FSS in 3D culture was briefly pointed out.

  20. Large-range Control of the Microstructures and Properties of Three-dimensional Porous Graphene

    PubMed Central

    Xie, Xiao; Zhou, Yilong; Bi, Hengchang; Yin, Kuibo; Wan, Shu; Sun, Litao

    2013-01-01

    Graphene-based three-dimensional porous macrostructures are believed of great importance in various applications, e.g. supercapacitors, photovoltaic cells, sensors and high-efficiency sorbents. However, to precisely control the microstructures and properties of this material to meet different application requirements in industrial practice remains challenging. We herein propose a facile and highly effective strategy for large-range tailoring the porous architecture and its properties by a modified freeze casting process. The pore sizes and wall thicknesses of the porous graphene can be gradually tuned by 80 times (from 10 to 800 μm) and 4000 times (from 20 nm to 80 μm), respectively. The property experiences the changing from hydrophilic to hydrophobic, with the Young's Modulus varying by 15 times. The fundamental principle of the porous microstructure evolution is discussed in detail. Our results demonstrate a very convenient and general protocol to finely tailor the structure and further benefit the various applications of porous graphene. PMID:23817081

  1. Three-dimensional phase transformation by impedance-matched dielectric slabs and generation of hollow beams based on transformation optics

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Yang, Shuaisai; Tang, Zhixiang; Shu, Weixing

    2016-10-01

    We propose a three-dimensional (3D) phase transformation method by an impedance-matched dielectric slab and apply it to generating hollow beams. We first employ transformation optics to establish a method for the transformation between two arbitrary 3D wavefronts through a flat dielectric and impedance-matched material. Then the method is used to convert a solid beam into a hollow beam with desired wavefront. By tuning the transformation surface, different hollow beams can be produced. The results are further validated by 3D finite-difference time-domain simulations.

  2. Reconstruction of mechanically recorded sound from an edison cylinder using three dimensional non-contact optical surface metrology

    SciTech Connect

    Fadeyev, V.; Haber, C.; Maul, C.; McBride, J.W.; Golden, M.

    2004-04-20

    Audio information stored in the undulations of grooves in a medium such as a phonograph disc record or cylinder may be reconstructed, without contact, by measuring the groove shape using precision optical metrology methods and digital image processing. The viability of this approach was recently demonstrated on a 78 rpm shellac disc using two dimensional image acquisition and analysis methods. The present work reports the first three dimensional reconstruction of mechanically recorded sound. The source material, a celluloid cylinder, was scanned using color coded confocal microscopy techniques and resulted in a faithful playback of the recorded information.

  3. Multif requency three-dimensional optical read-only memory disks using metallic island films: preliminary experiments.

    PubMed

    Baba, K; Yamada, R; Nakao, S; Miyagi, M

    1993-06-10

    Basic operation of new multifrequency three-dimensional (3-D) optical read-only memory (ROM) disks has been demonstrated experimentally. Several types of metallic island film exhibiting a selectiveresonance absorption in a visible-near infrared region are used as recording layers on the 3-D disks. The monochromatic light with a suitable wavelength near the resonance wavelength of each layer is used for the readout of information. We demonstrate that bar-code patterns recorded in silver and copper island layers can be read by using transmitted or reflected light. Furthermore, we also show that the 3-D disks with ≥3 recording layers can be realized. PMID:20829926

  4. Optical absorption enhancement with low structural-parameter sensitivity in three-dimensional silicon nanocavity array for solar photovoltaics

    NASA Astrophysics Data System (ADS)

    Zhang, Fuqiang; Sun, Ruinan; Hu, Ya; Peng, Kui-Qing

    2016-01-01

    Effective light trapping is essential for improving the efficiency and reducing the cost of thin-film silicon solar cells. Here, we numerically study the optical characteristics of periodic three-dimensional (3D) silicon nanocavity arrays. We found that the 3D silicon nanocavity array shows low sensitivity to geometric structural parameters for photon capture and achieves an outstanding efficiency superior to those of previously reported silicon nanostructures such as a nanowire and a nanohole with the same thickness. This excellence is attributed to a better antireflection capability and more resonant modes. The 3D silicon nanocavity array provides a new light-trapping strategy for thin-film photovoltaic devices.

  5. Three-dimensional canine displacement patterns in response to translation and controlled tipping retraction strategies

    PubMed Central

    Li, Shuning; Xia, Zeyang; Liu, Sean Shih-Yao; Eckert, George; Chen, Jie

    2014-01-01

    Objective To validate whether applying a well-defined initial three-dimensional (3D) load can create consistently expected tooth movement in patients. Materials and Methods Twenty-one patients who needed bilateral canine retraction to close extraction space were selected for this split-mouth clinical trial. After initial alignment and leveling, two canines in each patient were randomly assigned to receive either translation (TR) or controlled tipping (CT) load. The load was delivered by segmental T-loops designed to give specific initial moment/force ratios to the canines in each treatment interval (TI), verified with an orthodontic force tester. Maxillary dental casts were made before canine retraction and after each TI. The casts were digitized with a 3D laser scanner. The digital models were superimposed on the palatal rugae region. The 3D canine displacements and the displacement patterns in terms of TR, CT, and torque were calculated for each TI. Results The method can reliably detect a TR displacement greater than 0.3 mm and a rotation greater than 1.5°. Ninety-two TIs had displacements that were greater than 0.3 mm and were used for further analysis. Most displacements were oriented within ±45° from the distal direction. The displacement pattern in terms of TR or CT was not uniquely controlled by the initial moment/force ratio. Conclusions The initial load system is not the only key factor controlling tooth movement. Using a segmental T-loop with a well-controlled load system, large variations in canine displacement can be expected clinically. PMID:24885592

  6. Optical properties of chiral three-dimensional plasmonic oligomers at the onset of charge-transfer plasmons.

    PubMed

    Hentschel, Mario; Wu, Lin; Schäferling, Martin; Bai, Ping; Li, Er Ping; Giessen, Harald

    2012-11-27

    We demonstrate strong chiral optical response in three-dimensional chiral nanoparticle oligomers in the wavelength regime between 700 and 3500 nm. We show in experiment and simulation that this broad-band response occurs at the onset of charge transfer between the individual nanoparticles. The ohmic contact causes a strong red shift of the fundamental mode, while the geometrical shape of the resulting fused particles still allows for an efficient excitation of higher order modes. Calculated spectra and field distributions confirm our interpretation and show a number of interacting plasmonic modes. Our results deepen the understanding of the chiral optical response in complex chiral plasmonic nanostructures and pave the road toward broad-band chiral optical devices with strong responses, for example, for chiral plasmon rulers or sensing applications. PMID:23078518

  7. Coherent optical three-dimensional spectrum-correlation processing of wave signals based on space-time integration.

    PubMed

    Ezhov, Vasily

    2012-11-20

    The architectures of classical analog coherent optical (ACO) spectrum analyzers and correlators are not designed to process the wave signal as a whole, i.e., simultaneously in three dimensions. In this paper, the theory of ACO three-dimensional direct spectrum-correlation processing of spatial-temporal optical replicas (copies) of wave signals is discussed. In the single-stage and two-stage ACO systems, the spatial power spectrum and spatial correlation function of the wave signal (envelope) are obtained on the basis of space-time integration. The geometry of the final compressed signal in the output plane of either optical system allows one to evaluate the angle of wave arrival. The wave signal to be processed can theoretically have any form (due to autocorrelation properties of the systems) and an unlimited duration (due to time integration of wave energy and possibility of electronic subtraction of the intermediate bias terms of the time integration).

  8. Identification of muscle necrosis in the mdx mouse model of Duchenne muscular dystrophy using three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Klyen, Blake R.; Shavlakadze, Thea; Radley-Crabb, Hannah G.; Grounds, Miranda D.; Sampson, David D.

    2011-07-01

    Three-dimensional optical coherence tomography (3D-OCT) was used to image the structure and pathology of skeletal muscle tissue from the treadmill-exercised mdx mouse model of human Duchenne muscular dystrophy. Optical coherence tomography (OCT) images of excised muscle samples were compared with co-registered hematoxylin and eosin-stained and Evans blue dye fluorescence histology. We show, for the first time, structural 3D-OCT images of skeletal muscle dystropathology well correlated with co-located histology. OCT could identify morphological features of interest and necrotic lesions within the muscle tissue samples based on intrinsic optical contrast. These findings demonstrate the utility of 3D-OCT for the evaluation of small-animal skeletal muscle morphology and pathology, particularly for studies of mouse models of muscular dystrophy.

  9. Three-dimensional motion correction using speckle and phase for in vivo computed optical interferometric tomography

    PubMed Central

    Shemonski, Nathan D.; Ahn, Shawn S.; Liu, Yuan-Zhi; South, Fredrick A.; Carney, P. Scott; Boppart, Stephen A.

    2014-01-01

    Over the years, many computed optical interferometric techniques have been developed to perform high-resolution volumetric tomography. By utilizing the phase and amplitude information provided with interferometric detection, post-acquisition corrections for defocus and optical aberrations can be performed. The introduction of the phase, though, can dramatically increase the sensitivity to motion (most prominently along the optical axis). In this paper, we present two algorithms which, together, can correct for motion in all three dimensions with enough accuracy for defocus and aberration correction in computed optical interferometric tomography. The first algorithm utilizes phase differences within the acquired data to correct for motion along the optical axis. The second algorithm utilizes the addition of a speckle tracking system using temporally- and spatially-coherent illumination to measure motion orthogonal to the optical axis. The use of coherent illumination allows for high-contrast speckle patterns even when imaging apparently uniform samples or when highly aberrated beams cannot be avoided. PMID:25574426

  10. An optical profilometer for spatial characterization of three-dimensional surfaces

    NASA Technical Reports Server (NTRS)

    Kelly, W. L., IV; Burcher, E. E.; Skolaut, M. W., Jr.

    1977-01-01

    The design concept and system operation of an optical profilometer are discussed, and a preliminary evaluation of a breadboard system is presented to demonstrate the feasibility of the optical profilometer technique. Measurement results are presented for several test surfaces; and to illustrate a typical application, results are shown for a cleft palate cast used by dental surgeons. Finally, recommendations are made for future development of the optical profilometer technique for specific engineering or scientific applications.

  11. Three-dimensional endothelial cell morphogenesis under controlled ion release from copper-doped phosphate glass.

    PubMed

    Stähli, Christoph; James-Bhasin, Mark; Nazhat, Showan N

    2015-02-28

    Copper ions represent a promising angiogenic agent but are associated with cytotoxicity at elevated concentrations. Phosphate-based glasses (PGs) exhibit adjustable dissolution properties and allow for controlled ion release. This study examined the formation of capillary-like networks by SVEC4-10 endothelial cells (ECs) seeded in a three-dimensional (3D) type I collagen hydrogel matrix mixed with PG particles of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0 and 10 mol%). Copper and total phosphorus release decreased over time and was more sustained in the case of 10% CuO PG. Moreover, increasing the concentration of 10% CuO PG in collagen substantially delayed dissolution along with preferential release of copper. A 3D morphometric characterization method based on confocal laser scanning microscopy image stacks was developed in order to quantify EC network length, connectivity and branching. Network length was initially reduced in a concentration-dependent fashion by 10% CuO PG and, to a lesser extent, by 0% CuO PG, but reached values identical to the non-PG control by day 5 in culture. This reduction was attributed to a PG-mediated decrease in cell metabolic activity while cell proliferation as well as network connectivity and branching were independent of PG content. Gene expression of matrix metalloproteinases (MMP)-1 and -2 was up-regulated by PGs, indicating that MMPs did not play a critical role in network growth. The relationship between ion release and EC morphogenesis in 3D provided in this study is expected to contribute to an ultimately successful pro-angiogenic application of CuO-doped PGs. PMID:25575746

  12. Three-dimensional imaging of trabecular bone using the computer numerically controlled milling technique.

    PubMed

    Beck, J D; Canfield, B L; Haddock, S M; Chen, T J; Kothari, M; Keaveny, T M

    1997-09-01

    Although various techniques exist for high-resolution, three-dimensional imaging of trabecular bone, a common limitation is that resolution depends on specimen size. Most techniques also have limited availability due to their expense and complexity. We therefore developed a simple, accurate technique that has a resolution that is independent of specimen size. Thin layers are serially removed from an embedded bone specimen using a computer numerically controlled (CNC) milling machine, and each exposed cross section is imaged using a low-magnification digital camera. Precise positioning of the specimen under the camera is achieved using the programmable feature of the CNC milling machine. Large specimens are imaged without loss of resolution by moving the specimen under the camera such that an array of field-of-views spans the full cross section. The images from each field-of-view are easily assembled and registered in the postprocessing. High-contrast sections are achieved by staining the bone black with silver nitrate and embedding it in whitened methylmethacrylate. Due to the high contrast nature and high resolution of the images, thresholding at a single value yielded excellent predictions of morphological parameters such as bone volume fraction (mean +/- SD percent error = 0.70 +/- 4.28%). The main limitations of this fully automated "CNC milling technique" are that the specimen is destroyed and the process is relatively slow. However, because of its accuracy, independence of image resolution from specimen size, and ease of implementation, this new technique is an excellent method for ex situ imaging of trabecular architecture, particularly when high resolution is required.

  13. Hybrid optics for three-dimensional microstructuring of polymers via direct laser writing

    NASA Astrophysics Data System (ADS)

    Burmeister, Frank; Zeitner, Uwe D.; Nolte, Stefan; Tünnermann, Andreas

    2012-03-01

    We present an immersion hybrid optics specially designed for focusing ultrashort laser pulses into a polymer for direct laser writing via two-photon polymerization. The hybrid optics enables well corrected focusing over a working distance range of 577 μm with a numerical aperture (NA) of 1.33 thereby causing low internal dispersion. We combine the concepts of an aplanatic solid immersion lens (ASIL) for achieving a high NA with the correction of aberrations with a diffractive optical element (DOE). To demonstrate the improvements for volume structuring of the polymer, we compare achievable feature sizes of structures written with our optics and a commercial available oil immersion objective (100x, NA=1.4).

  14. Three-dimensional nanometer-scale optical cavities of indefinite medium.

    PubMed

    Yao, Jie; Yang, Xiaodong; Yin, Xiaobo; Bartal, Guy; Zhang, Xiang

    2011-07-12

    Miniaturization of optical cavities has numerous advantages for enhancing light-matter interaction in quantum optical devices, low-threshold lasers with minimal power consumption, and efficient integration of optoelectronic devices at large scale. However, the realization of a truly nanometer-scale optical cavity is hindered by the diffraction limit of the nature materials. In addition, the scaling of the photon life time with the cavity size significantly reduces the quality factor of small cavities. Here we theoretically present an approach to achieve ultrasmall optical cavities using indefinite medium with hyperbolic dispersion, which allows propagation of electromagnetic waves with wave vectors much larger than those in vacuum enabling extremely small 3D cavity down to (λ/20)(3). These cavities exhibit size-independent resonance frequencies and anomalous scaling of quality factors in contrast to the conventional cavities, resulting in nanocavities with both high Q/V(m) ratio and broad bandwidth.

  15. Reconstruction of three-dimensional occluded object using optical flow and triangular mesh reconstruction in integral imaging.

    PubMed

    Jung, Jae-Hyun; Hong, Keehoon; Park, Gilbae; Chung, Indeok; Park, Jae-Hyeung; Lee, Byoungho

    2010-12-01

    We proposed a reconstruction method for the occluded region of three-dimensional (3D) object using the depth extraction based on the optical flow and triangular mesh reconstruction in integral imaging. The depth information of sub-images from the acquired elemental image set is extracted using the optical flow with sub-pixel accuracy, which alleviates the depth quantization problem. The extracted depth maps of sub-image array are segmented by the depth threshold from the histogram based segmentation, which is represented as the point clouds. The point clouds are projected to the viewpoint of center sub-image and reconstructed by the triangular mesh reconstruction. The experimental results support the validity of the proposed method with high accuracy of peak signal-to-noise ratio and normalized cross-correlation in 3D image recognition.

  16. Stable Fulde-Ferrell-Larkin-Ovchinnikov pairing states in two-dimensional and three-dimensional optical lattices

    SciTech Connect

    Cai Zi; Wu Congjun; Wang Yupeng

    2011-06-15

    We present the study of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing states in the p-orbital bands in both two- and three-dimensional optical lattices. Due to the quasi-one-dimensional band structure which arises from the unidirectional hopping of the orthogonal p orbitals, the pairing phase space is not affected by spin imbalance. Furthermore, interactions build up high-dimensional phase coherence which stabilizes the FFLO states in 2D and 3D optical lattices in a large parameter regime in the phase diagram. These FFLO phases are stable with the imposition of the inhomogeneous trapping potential. Their entropies are comparable to the normal states at finite temperatures.

  17. Two- and three-dimensional optical tomography of finger joints for diagnostics of rheumatoid arthritis

    NASA Astrophysics Data System (ADS)

    Klose, Alexander D.; Hielscher, Andreas H.; Hanson, Kenneth M.; Beuthan, Juergen

    1998-12-01

    Rheumatoid arthritis (RA) is one of the most common diseases of human joints. This progressive disease is characterized by an inflammation process that originates in the inner membrane (synovalis) of the capsule and spreads to other parts of the joint. In early stages the synovalis thickness and the permeability of this membrane changes. This leads to changes in the optical parameters of the synovalis and the synovial fluid (synovia), which occupies the space between the bones. The synovia changes from a clear yellowish fluid to a turbid grayish substance. In this work we present 2 and 3-dimensional reconstruction schemes for optical tomography of the finger joints. Our reconstruction algorithm is based on the diffusion approximation and employs adjoint differentiation techniques for the gradient calculation of the objective function with respect to the spatial distribution of optical properties. In this way, the spatial distribution of optical properties within the joints is reconstructed with high efficiency and precision. Volume information concerning the synovial space and the capsula are provided. Furthermore, it is shown that small changes of the scattering coefficients can be monitored. Therefore, optical tomography has the potential of becoming a useful tool for the early diagnosis and monitoring of disease progression in RA.

  18. Three-dimensional phase-contrast X-ray microtomography with scanning-imaging X-ray microscope optics.

    PubMed

    Takeuchi, Akihisa; Uesugi, Kentaro; Suzuki, Yoshio

    2013-09-01

    A three-dimensional (3D) X-ray tomographic micro-imaging system has been developed. The optical system is based on a scanning-imaging X-ray microscope (SIXM) optics, which is a hybrid system consisting of a scanning microscope optics with a one-dimensional (1D) focusing (line-focusing) device and an imaging microscope optics with a 1D objective. In the SIXM system, each 1D dataset of a two-dimensional (2D) image is recorded independently. An object is illuminated with a line-focused beam. Positional information of the region illuminated by the line-focused beam is recorded with the 1D imaging microscope optics as line-profile data. By scanning the object with the line focus, 2D image data are obtained. In the same manner as for a scanning microscope optics with a multi-pixel detector, imaging modes such as phase contrast and absorption contrast can be arbitrarily configured after the image data acquisition. By combining a tomographic scan method and the SIXM system, quantitative 3D imaging is performed. Results of a feasibility study of the SIXM for 3D imaging are shown.

  19. Elevating optical activity: Efficient on-edge lithography of three-dimensional starfish metamaterial

    NASA Astrophysics Data System (ADS)

    Dietrich, K.; Menzel, C.; Lehr, D.; Puffky, O.; Hübner, U.; Pertsch, T.; Tünnermann, A.; Kley, E.-B.

    2014-05-01

    We present an approach for extremely fast, wafer-scale fabrication of chiral starfish metamaterials based on electron beam- and on-edge lithography. A millimeter sized array of both the planar chiral and the true 3D chiral starfish is realized, and their chiroptical performances are compared by circular dichroism measurements. We find optical activity in the visible and near-infrared spectral range, where the 3D starfish clearly outperforms the planar design by almost 2 orders of magnitude, though fabrication efforts are only moderately increased. The presented approach is capable of bridging the gap between high performance optical chiral metamaterials and industrial production by nanoimprint technology.

  20. Elevating optical activity: Efficient on-edge lithography of three-dimensional starfish metamaterial

    SciTech Connect

    Dietrich, K. Menzel, C.; Lehr, D.; Puffky, O.; Pertsch, T.; Tünnermann, A.; Kley, E.-B.; Hübner, U.

    2014-05-12

    We present an approach for extremely fast, wafer-scale fabrication of chiral starfish metamaterials based on electron beam- and on-edge lithography. A millimeter sized array of both the planar chiral and the true 3D chiral starfish is realized, and their chiroptical performances are compared by circular dichroism measurements. We find optical activity in the visible and near-infrared spectral range, where the 3D starfish clearly outperforms the planar design by almost 2 orders of magnitude, though fabrication efforts are only moderately increased. The presented approach is capable of bridging the gap between high performance optical chiral metamaterials and industrial production by nanoimprint technology.

  1. Three-dimensional quasi-conformal transformation optics through numerical optimization.

    PubMed

    Junqueira, Mateus A F C; Gabrielli, Lucas H; Beltrán-Mejía, Felipe; Spadoti, Danilo H

    2016-07-25

    In this paper we demonstrate the possibility to achieve 3-dimensional quasi-conformal transformation optics through parametrization and numerical optimization without using sliding boundary conditions. The proposed technique, which uses a quasi-Newton method, is validated in two cylindrical waveguide bends as design examples. Our results indicate an arbitrarily small average anisotropy can be achieved in 3D transformation optics as the number of degrees of freedom provided by the parametrization was increased. The waveguide simulations confirm modal preservation when the residual anisotropy is neglected.

  2. High-resolution x-ray guided three-dimensional diffuse optical tomography of joint tissues in hand osteoarthritis: Morphological and functional assessments

    SciTech Connect

    Yuan Zhen; Zhang Qizhi; Sobel, Eric S.; Jiang Huabei

    2010-08-15

    Purpose: The aim of this study was to investigate the potential use of multimodality functional imaging techniques to identify the quantitative optical findings that can be used to distinguish between osteoarthritic and normal finger joints. Methods: Between 2006 and 2009, the distal interphalangeal finger joints from 40 female subjects including 22 patients and 18 healthy controls were examined clinically and scanned by a hybrid imaging system. This system integrated x-ray tomosynthetic setup with a diffuse optical imaging system. Optical absorption and scattering images were recovered based on a regularization-based hybrid reconstruction algorithm. A receiver operating characteristic curve was used to calculate the statistical significance of specific optical features obtained from osteoarthritic and healthy joints groups. Results: The three-dimensional optical and x-ray images captured made it possible to quantify optical properties and joint space width of finger joints. Based on the recovered optical absorption and scattering parameters, the authors observed statistically significant differences between healthy and osteoarthritis finger joints. Conclusions: The statistical results revealed that sensitivity and specificity values up to 92% and 100%, respectively, can be achieved when optical properties of joint tissues were used as classifiers. This suggests that these optical imaging parameters are possible indicators for diagnosing osteoarthritis and monitoring its progression.

  3. Three-Dimensional Optical Reconstruction of Vocal Fold Kinematics Using High-Speed Video With a Laser Projection System.

    PubMed

    Luegmair, Georg; Mehta, Daryush D; Kobler, James B; Döllinger, Michael

    2015-12-01

    Vocal fold kinematics and its interaction with aerodynamic characteristics play a primary role in acoustic sound production of the human voice. Investigating the temporal details of these kinematics using high-speed videoendoscopic imaging techniques has proven challenging in part due to the limitations of quantifying complex vocal fold vibratory behavior using only two spatial dimensions. Thus, we propose an optical method of reconstructing the superior vocal fold surface in three spatial dimensions using a high-speed video camera and laser projection system. Using stereo-triangulation principles, we extend the camera-laser projector method and present an efficient image processing workflow to generate the three-dimensional vocal fold surfaces during phonation captured at 4000 frames per second. Initial results are provided for airflow-driven vibration of an ex vivo vocal fold model in which at least 75% of visible laser points contributed to the reconstructed surface. The method captures the vertical motion of the vocal folds at a high accuracy to allow for the computation of three-dimensional mucosal wave features such as vibratory amplitude, velocity, and asymmetry.

  4. Three-dimensional optical reconstruction of vocal fold kinematics using high-speed video with a laser projection system

    PubMed Central

    Luegmair, Georg; Mehta, Daryush D.; Kobler, James B.; Döllinger, Michael

    2015-01-01

    Vocal fold kinematics and its interaction with aerodynamic characteristics play a primary role in acoustic sound production of the human voice. Investigating the temporal details of these kinematics using high-speed videoendoscopic imaging techniques has proven challenging in part due to the limitations of quantifying complex vocal fold vibratory behavior using only two spatial dimensions. Thus, we propose an optical method of reconstructing the superior vocal fold surface in three spatial dimensions using a high-speed video camera and laser projection system. Using stereo-triangulation principles, we extend the camera-laser projector method and present an efficient image processing workflow to generate the three-dimensional vocal fold surfaces during phonation captured at 4000 frames per second. Initial results are provided for airflow-driven vibration of an ex vivo vocal fold model in which at least 75% of visible laser points contributed to the reconstructed surface. The method captures the vertical motion of the vocal folds at a high accuracy to allow for the computation of three-dimensional mucosal wave features such as vibratory amplitude, velocity, and asymmetry. PMID:26087485

  5. Using nanoscale and mesoscale anisotropy to engineer the optical response of three-dimensional plasmonic metamaterials.

    PubMed

    Ross, Michael B; Blaber, Martin G; Schatz, George C

    2014-06-17

    The a priori ability to design electromagnetic wave propagation is crucial for the development of novel metamaterials. Incorporating plasmonic building blocks is of particular interest due to their ability to confine visible light. Here we explore the use of anisotropy in nanoscale and mesoscale plasmonic array architectures to produce noble metal-based metamaterials with unusual optical properties. We find that the combination of nanoscale and mesoscale anisotropy leads to rich opportunities for metamaterials throughout the visible and near-infrared. The low volume fraction (<5%) plasmonic metamaterials explored herein exhibit birefringence, a skin depth approaching that of pure metals for selected wavelengths, and directionally confined waves similar to those found in optical fibres. These data provide design principles with which the electromagnetic behaviour of plasmonic metamaterials can be tailored using high aspect ratio nanostructures that are accessible via a variety of synthesis and assembly methods.

  6. Using nanoscale and mesoscale anisotropy to engineer the optical response of three-dimensional plasmonic metamaterials

    NASA Astrophysics Data System (ADS)

    Ross, Michael B.; Blaber, Martin G.; Schatz, George C.

    2014-06-01

    The a priori ability to design electromagnetic wave propagation is crucial for the development of novel metamaterials. Incorporating plasmonic building blocks is of particular interest due to their ability to confine visible light. Here we explore the use of anisotropy in nanoscale and mesoscale plasmonic array architectures to produce noble metal-based metamaterials with unusual optical properties. We find that the combination of nanoscale and mesoscale anisotropy leads to rich opportunities for metamaterials throughout the visible and near-infrared. The low volume fraction (<5%) plasmonic metamaterials explored herein exhibit birefringence, a skin depth approaching that of pure metals for selected wavelengths, and directionally confined waves similar to those found in optical fibres. These data provide design principles with which the electromagnetic behaviour of plasmonic metamaterials can be tailored using high aspect ratio nanostructures that are accessible via a variety of synthesis and assembly methods.

  7. Three-dimensional line-field Fourier domain optical coherence tomography for in vivo dermatological investigation.

    PubMed

    Yasuno, Yoshiaki; Endo, Takashi; Makita, Shuichi; Aoki, Gouki; Itoh, Masahide; Yatagai, Toyohiko

    2006-01-01

    We demonstrate 3-D optical coherence tomography using only 1-D mechanical scanning. This system uses the principle of Fourier domain optical coherence tomography for depth resolution, 1-D imaging for lateral vertical resolution, and mechanical scanning by a galvanometer for lateral horizontal resolution. An in vivo human fingerpad is investigated in three dimensions with an image size of 480 points (vertical) x 300 points (horizontal) x 1024 points (depth), which corresponds to 2.1 x 1.4 x 1.3 mm. The acquisition time for a single cross section is 1 ms and that for a single volume is 10 s. The system sensitivity is 75.6 dB at a probe beam power of 1.1 mW. PMID:16526891

  8. Three-dimensional display utilizing a diffractive optical element and an active matrix liquid crystal display

    NASA Astrophysics Data System (ADS)

    Nordin, Gregory P.; Jones, Michael W.; Kulick, Jeffrey H.; Lindquist, Robert G.; Kowel, Stephen T.

    1996-12-01

    We describe the design, construction, and performance of the first real-time autostereoscopic 3D display based on the partial pixel 3D display architecture. The primary optical components of the 3D display are an active-matrix liquid crystal display and a diffractive optical element (DOE). The display operates at video frame rates and is driven with a conventional VGA signal. 3D animations with horizontal motion parallax are readily viewable as sets of stereo images. Formation of the virtual viewing slits by diffraction from the partial pixel apertures is experimentally verified. The measured contrast and perceived brightness of the display are excellent, but there are minor flaws in image quality due to secondary images. The source of these images and how they may be eliminated is discussed. The effects of manufacturing-related systematic errors in the DOE are also analyzed.

  9. Three-dimensional ideal theta(1)/theta(2) angular transformer and its uses in fiber optics.

    PubMed

    Ning, X

    1988-10-01

    A 3-D ideal theta(1)/theta(2) angular transformer in nonimaging optics is introduced. The axially symmetric transformer, combining a portion of a hyperbolic concentrator with two lenses, transforms an input limited Lambertian over an angle theta(1) to an output limited Lambertian over an angle theta(2) without losing throughput. This is the first known transformer with such ideal properties. Results of computer simulations of a transformer with planospherical lenses are presented. Because of its ideal angular transforming property, the transformer offers an excellent solution for power launching and fiber-fiber coupling in optical fiber systems. In principle, the theoretical maximum coupling efficiency based on radiance conservation can be achieved with this transformer. Several conceptual designs of source-fiber and fiber-fiber couplers using the transformer are given. PMID:20539526

  10. Three-dimensional imaging of intracochlear tissue by scanning laser optical tomography (SLOT)

    NASA Astrophysics Data System (ADS)

    Tinne, N.; Nolte, L.; Antonopoulos, G. C.; Schulze, J.; Andrade, J.; Heisterkamp, A.; Meyer, H.; Warnecke, A.; Majdani, O.; Ripken, T.

    2016-02-01

    The presented study focuses on the application of scanning laser optical tomography (SLOT) for non-destructive visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique, which allows for tomographic imaging of the internal structure of transparent large-scale specimens (up to 1 cm3). Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises mechanically assisted decalcification, dehydration as well as optical clearing of the cochlea samples. Here, we demonstrate results of SLOT visualizing hard and soft tissue structures of the human cochlea with an optical resolution in the micrometer range using absorption and autofluorescence as contrast mechanisms. Furthermore, we compare our results with the method of X-ray micro tomography (micro-CT, μCT) as clinical gold standard which is based only on absorption. In general, SLOT can provide the advantage of covering all contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. For this reason, a protocol for antibody staining has been developed, which additionally enables selective mapping of cellular structures within the cochlea. Thus, we present results of SLOT imaging rodent cochleae showing specific anatomical structures such as hair cells and neurofilament via fluorescence. In conclusion, the presented study has shown that SLOT is an ideally suited tool in the field of otology for in toto visualization of the inner ear microstructure.

  11. Evaluating a hybrid three-dimensional metrology system: merging data from optical and touch probe devices

    NASA Astrophysics Data System (ADS)

    Gerde, Janice R.; Christens-Barry, William A.

    2011-08-01

    In a project to meet requirements for CBP Laboratory analysis of footwear under the Harmonized Tariff Schedule of the United States (HTSUS), a hybrid metrology system comprising both optical and touch probe devices has been assembled. A unique requirement must be met: To identify the interface-typically obscured in samples of concern-of the "external surface area upper" (ESAU) and the sole without physically destroying the sample. The sample outer surface is determined by discrete point cloud coordinates obtained using laser scanner optical measurements. Measurements from the optically inaccessible insole region are obtained using a coordinate measuring machine (CMM). That surface similarly is defined by point cloud data. Mathematically, the individual CMM and scanner data sets are transformed into a single, common reference frame. Custom software then fits a polynomial surface to the insole data and extends it to intersect the mesh fitted to the outer surface point cloud. This line of intersection defines the required ESAU boundary, thus permitting further fractional area calculations to determine the percentage of materials present. With a draft method in place, and first-level method validation underway, we examine the transformation of the two dissimilar data sets into the single, common reference frame. We also will consider the six previously-identified potential error factors versus the method process. This paper reports our on-going work and discusses our findings to date.

  12. Peptidic ligands to control the three-dimensional self-assembly of quantum rods in aqueous media.

    PubMed

    Bizien, Thomas; Even-Hernandez, Pascale; Postic, Marie; Mazari, Elsa; Chevance, Soizic; Bondon, Arnaud; Hamon, Cyrille; Troadec, David; Largeau, Ludovic; Dupuis, Christophe; Gosse, Charlie; Artzner, Franck; Marchi, Valérie

    2014-09-24

    The use of peptidic ligands is validated as a generic chemical platform allowing one to finely control the organization in solid phase of semiconductor nanorods originally dispersed in an aqueous media. An original method to generate, on a macroscopic scale and with the desired geometry, three-dimensional supracrystals composed of quantum rods is introduced. In a first step, nanorods are transferred in an aqueous phase thanks to the substitution of the original capping layer by peptidic ligands. Infrared and nuclear magnetic resonance spectroscopy data prove that the exchange is complete; fluorescence spectroscopy demonstrates that the emitter optical properties are not significantly altered; electrophoresis and dynamic light scattering experiments assess the good colloidal stability of the resulting aqueous suspension. In a second step, water evaporation in a microstructured environment yields superstructures with a chosen geometry and in which nanorods obey a smectic B arrangement, as shown by electron microscopy. Incidentally, bulk drying in a capillary tube generates a similar local order, as evidenced by small angle X-ray scattering.

  13. Three-dimensional choroidal segmentation in spectral OCT volumes using optic disc prior information

    NASA Astrophysics Data System (ADS)

    Hu, Zhihong; Girkin, Christopher A.; Hariri, Amirhossein; Sadda, SriniVas R.

    2016-03-01

    Recently, much attention has been focused on determining the role of the peripapillary choroid - the layer between the outer retinal pigment epithelium (RPE)/Bruchs membrane (BM) and choroid-sclera (C-S) junction, whether primary or secondary in the pathogenesis of glaucoma. However, the automated choroidal segmentation in spectral-domain optical coherence tomography (SD-OCT) images of optic nerve head (ONH) has not been reported probably due to the fact that the presence of the BM opening (BMO, corresponding to the optic disc) can deflect the choroidal segmentation from its correct position. The purpose of this study is to develop a 3D graph-based approach to identify the 3D choroidal layer in ONH-centered SD-OCT images using the BMO prior information. More specifically, an initial 3D choroidal segmentation was first performed using the 3D graph search algorithm. Note that varying surface interaction constraints based on the choroidal morphological model were applied. To assist the choroidal segmentation, two other surfaces of internal limiting membrane and innerouter segment junction were also segmented. Based on the segmented layer between the RPE/BM and C-S junction, a 2D projection map was created. The BMO in the projection map was detected by a 2D graph search. The pre-defined BMO information was then incorporated into the surface interaction constraints of the 3D graph search to obtain more accurate choroidal segmentation. Twenty SD-OCT images from 20 healthy subjects were used. The mean differences of the choroidal borders between the algorithm and manual segmentation were at a sub-voxel level, indicating a high level segmentation accuracy.

  14. Optical and transport properties in three-dimensional Dirac and Weyl semimetals

    NASA Astrophysics Data System (ADS)

    Tabert, C. J.; Carbotte, J. P.; Nicol, E. J.

    2016-02-01

    Within a Kubo formalism, we study dc transport and ac optical properties of 3D Dirac and Weyl semimetals. Emphasis is placed on the approach to charge neutrality and on the differences between Dirac and Weyl materials. At charge neutrality, the zero-temperature limit of the dc conductivity is not universal and also depends on the residual scattering model employed. However, the Lorenz number L retains its usual value L0. With increasing temperature, the Wiedemann-Franz law is violated. At high temperatures, L exhibits a new plateau at a value dependent on the details of the scattering rate. Such details can also appear in the optical conductivity, both in the Drude response and interband background. In the clean limit, the interband background is linear in photon energy and always extrapolates to the origin. This background can be shifted to the right through the introduction of a massless gap. In this case, the extrapolation can cut the axis at a finite photon energy as is observed in some experiments. It is also of interest to differentiate between the two types of Weyl semimetals: those with broken time-reversal symmetry and those with broken spatial-inversion symmetry. We show that, while the former will follow the same behavior as the 3D Dirac semimetals, for the zero magnetic field properties discussed here, the latter type will show a double step in the optical conductivity at finite doping and a single absorption edge at charge neutrality. The Drude conductivity is always finite in this case, even at charge neutrality.

  15. Tilted view reconstruction in optical microscopy. Three-dimensional reconstruction of Drosophila melanogaster embryo nuclei.

    PubMed Central

    Shaw, P J; Agard, D A; Hiraoka, Y; Sedat, J W

    1989-01-01

    The resolution along the optical axis (z) is much less than the in-plane resolution in any current optical microscope, conventional or otherwise. We have used mutually tilted, through-focal section views of the same object to provide a solution to this problem. A tilting specimen stage was constructed for an optical microscope, which with the use of a coverslip-free water immersion lens, allowed the collection of data sets from intact Drosophila melanogaster embryos at viewing directions up to 90 degrees apart. We have devised an image processing scheme to determine the relative tilt, translation, and sampling parameters of the different data sets. This involves the use of a modified phase cross-correlation function, which produces a very sharp maximum. Finally the data sets are merged using figure-of-merit and local area scaling techniques borrowed from x-ray protein crystallography. We demonstrate the application of this technique to data sets from a metaphase plate in an embryo of Drosophila melanogaster. As expected, the merged reconstruction combined the highest resolution available in the individual data sets. As estimated from the Fourier transform, the final resolution is 0.25 microns in x and y and 0.4 microns in z. In the final reconstruction all ten chromosome arms can be easily delineated; this was not possible in the individual data sets. Within many of the arms the two individual chromatids can be seen. In some cases the chromatids are wrapped around each other helically, in others they lie alongside each other in a parallel arrangement. Images FIGURE 1 FIGURE 3 FIGURE 4 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 PMID:2495031

  16. A three dimensional radiative transfer method for optical remote sensing of vegetated land surfaces

    NASA Technical Reports Server (NTRS)

    Asrar, Ghassem; Myneni, Ranga B.; Choudhury, Bhaskar J.

    1991-01-01

    In the application of remote sensing at optical wavelengths to vegetated surfaces from satellite borne high resolution instruments, an understanding of the various physical mechanisms that contribute to the measured signal is important. A numerical method of solving the radiative transfer equation in three dimensions is reported. The reliability of coding and accuracy of the algorithm are evaluated by benchmarching. Parametrization of the methods and results of a simulation are presented. The method is tested with experimental data of canopy bidirectional reflectance factors. The effect of spatial heterogeneity on the relationship between the simple ratio and normalized vrs absorbed Photosynthetically Active Radiation (PAR) is discussed.

  17. Visualizing biofilm formation in endotracheal tubes using endoscopic three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Heidari, Andrew E.; Moghaddam, Samer; Troung, Kimberly K.; Chou, Lidek; Genberg, Carl; Brenner, Matthew; Chen, Zhongping

    2015-12-01

    Biofilm formation has been linked to ventilator-associated pneumonia, which is a prevalent infection in hospital intensive care units. Currently, there is no rapid diagnostic tool to assess the degree of biofilm formation or cellular biofilm composition. Optical coherence tomography (OCT) is a minimally invasive, nonionizing imaging modality that can be used to provide high-resolution cross-sectional images. Biofilm deposited in critical care patients' endotracheal tubes was analyzed in vitro. This study demonstrates that OCT could potentially be used as a diagnostic tool to analyze and assess the degree of biofilm formation and extent of airway obstruction caused by biofilm in endotracheal tubes.

  18. Reduction of image artifacts in three-dimensional optical coherence tomography of skin in vivo.

    PubMed

    Liew, Yih Miin; McLaughlin, Robert A; Wood, Fiona M; Sampson, David D

    2011-11-01

    This paper presents results of in vivo studies on the effect of refractive index-matching media on image artifacts in optical coherence tomography (OCT) images of human skin. These artifacts present as streaks of artificially low backscatter and displacement or distortion of features. They are primarily caused by refraction and scattering of the OCT light beam at the skin surface. The impact of the application of glycerol and ultrasound gel is assessed on both novel skin-mimicking phantoms and in vivo human skin, including assessment of the epidermal thickening caused by the media. Based on our findings, recommendations are given for optimal OCT imaging of skin in vivo. PMID:22112123

  19. Three-dimensional optical tomographic brain imaging during kainic-acid-induced seizures in rats

    NASA Astrophysics Data System (ADS)

    Bluestone, Avraham Y.; Sakamoto, Kenichi; Hielscher, Andreas H.; Stewart, Mark

    2005-04-01

    In this study, we explored the potential of diffuse optical tomography for brain oximetry and describe our efforts towards imaging hemodynamic changes in rat brains during kainic-acid (KA) induced seizures. Using electrophysiological techniques we first showed that KA induces a pronounced transient hypotension in urethane anesthetized rats that is coincident with seizure activity beginning in ventral and spreading to dorsal hippocampus. We observed sustained increases in vagus and sympathetic activity during generalized limbic seizure activity, which alters blood pressure regulation and heart rhythms. Subsequently, we used optical tomographic methods to study KA induced seizures in anesthetized animals to better define the hemodynamic cerebral vascular response. We observed a lateralized increase in deoxyhemoglobin after KA injection at the time when the blood pressure (BP) was decreased. By contrast, injection of phenylephrine produced a symmetric global increase in total hemoglobin. These findings indicate that our instrument is sensitive to the local hemodynamics, both in response to a global increase in blood pressure (phenylephrine injection) and a lateralized decrease in oxyhemoglobin produced by an asymmetric response to KA; a response that may be critically important for severe autonomic nervous system alterations during seizures. The results of this study provide the impetus for combining complimentary modalities, imaging and electrophysiological, to ultimately gain a better understanding of the underlying physiology of seizure activity in the rat.

  20. Three-dimensional optical coherence tomography of the embryonic murine cardiovascular system

    NASA Astrophysics Data System (ADS)

    Luo, Wei; Marks, Daniel L.; Ralston, Tyler S.; Boppart, Stephen A.

    2006-03-01

    Optical coherence tomography (OCT) is an emerging high-resolution real-time biomedical imaging technology that has potential as a novel investigational tool in developmental biology and functional genomics. In this study, murine embryos and embryonic hearts are visualized with an OCT system capable of 2-µm axial and 15-µm lateral resolution and with real-time acquisition rates. We present, to our knowledge, the first sets of high-resolution 2- and 3-D OCT images that reveal the internal structures of the mammalian (murine) embryo (E10.5) and embryonic (E14.5 and E17.5) cardiovascular system. Strong correlations are observed between OCT images and corresponding hematoxylin- and eosin-stained histological sections. Real-time in vivo embryonic (E10.5) heart activity is captured by spectral-domain optical coherence tomography, processed, and displayed at a continuous rate of five frames per second. With the ability to obtain not only high-resolution anatomical data but also functional information during cardiovascular development, the OCT technology has the potential to visualize and quantify changes in murine development and in congenital and induced heart disease, as well as enable a wide range of basic in vitro and in vivo research studies in functional genomics.

  1. Three-dimensional segmentation and reconstruction of the retinal vasculature from spectral-domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Guimarães, Pedro; Rodrigues, Pedro; Celorico, Dirce; Serranho, Pedro; Bernardes, Rui

    2015-01-01

    We reconstruct the three-dimensional shape and location of the retinal vascular network from commercial spectral-domain (SD) optical coherence tomography (OCT) data. The two-dimensional location of retinal vascular network on the eye fundus is obtained through support vector machines classification of properly defined fundus images from OCT data, taking advantage of the fact that on standard SD-OCT, the incident light beam is absorbed by hemoglobin, creating a shadow on the OCT signal below each perfused vessel. The depth-wise location of the vessel is obtained as the beginning of the shadow. The classification of crossovers and bifurcations within the vascular network is also addressed. We illustrate the feasibility of the method in terms of vessel caliber estimation and the accuracy of bifurcations and crossovers classification.

  2. Elastic stiffness characterization using three-dimensional full-field deformation obtained with optical coherence tomography and digital volume correlation.

    PubMed

    Fu, Jiawei; Pierron, Fabrice; Ruiz, Pablo D

    2013-12-01

    This paper presents a methodology for stiffness identification from depth-resolved three-dimensional (3-D) full-field deformation fields. These were obtained by performing digital volume correlation on optical coherence tomography volume reconstructions of silicone rubber phantoms. The effect of noise and reconstruction uncertainties on the performance of the correlation algorithm was first evaluated through stationary and rigid body translation tests to give an indication of the minimum strain that can be reliably measured. The phantoms were then tested under tension, and the 3-D deformation fields were used to identify the elastic constitutive parameters using a 3-D manually defined virtual fields method. The identification results for the cases of uniform and heterogeneous strain fields were compared with those calculated analytically through the constant uniaxial stress assumption, showing good agreement.

  3. Gold coated optical fibers as three-dimensional electrodes for microfluidic enzymatic biofuel cells: Toward geometrically enhanced performance

    PubMed Central

    Desmaële, Denis; Renaud, Louis; Tingry, Sophie

    2015-01-01

    For the first time, we report on the preliminary evaluation of gold coated optical fibers (GCOFs) as three-dimensional (3D) electrodes for a membraneless glucose/O2 enzymatic biofuel cell. Two off-the-shelf 125 μm diameter GCOFs were integrated into a 3D microfluidic chip fabricated via rapid prototyping. Using soluble enzymes and a 10 mM glucose solution flowing at an average velocity of 16 mm s−1 along 3 mm long GCOFs, the maximum power density reached 30.0 ± 0.1 μW cm−2 at a current density of 160.6 ± 0.3 μA cm−2. Bundles composed of multiple GCOFs could further enhance these first results while serving as substrates for enzyme immobilization. PMID:26339305

  4. Demonstration of a Controllable Three-Dimensional Brownian Motor in Symmetric Potentials

    SciTech Connect

    Sjoelund, P.; Petra, S.J.H.; Dion, C.M.; Jonsell, S.; Nylen, M.; Kastberg, A.; Sanchez-Palencia, L.

    2006-05-19

    We demonstrate a Brownian motor, based on cold atoms in optical lattices, where isotropic random fluctuations are rectified in order to induce controlled atomic motion in arbitrary directions. In contrast to earlier demonstrations of ratchet effects, our Brownian motor operates in potentials that are spatially and temporally symmetric, but where spatiotemporal symmetry is broken by a phase shift between the potentials and asymmetric transfer rates between them. The Brownian motor is demonstrated in three dimensions and the noise-induced drift is controllable in our system.

  5. Generation of tunable chain of three-dimensional optical bottle beams via focused multi-ring hollow Gaussian beam.

    PubMed

    Philip, Geo M; Viswanathan, Nirmal K

    2010-11-01

    We report here the generation of a chain of three-dimensional (3-D) optical bottle beams by focusing a π-phase shifted multi-ring hollow Gaussian beam (HGB) using a lens with spherical aberration. The rings of the HGB of suitable radial (k(r)) and axial (k(z)) wave vectors are generated using a double-negative axicon chemically etched in the optical fiber tips. Moving the lens position with respect to the fiber tip results in variation of the semi-angle of the cones of wave vectors of the HGBs and their diameter, using which we demonstrate tunability in the size and the periodicity of the 3-D optical bottle beams over a wide range, from micrometers to millimeters. The propagation characteristics of the beams resulting from focusing of single- and multi-ring HGBs and resulting in a quasi-non-diffracting beam and a chain of 3-D optical bottle beams, respectively, are simulated using only the input beam parameters and are found to agree well with experimental results.

  6. Development of a three-dimensional correction method for optical distortion of flow field inside a liquid droplet.

    PubMed

    Gim, Yeonghyeon; Ko, Han Seo

    2016-04-15

    In this Letter, a three-dimensional (3D) optical correction method, which was verified by simulation, was developed to reconstruct droplet-based flow fields. In the simulation, a synthetic phantom was reconstructed using a simultaneous multiplicative algebraic reconstruction technique with three detectors positioned at the synthetic object (represented by the phantom), with offset angles of 30° relative to each other. Additionally, a projection matrix was developed using the ray tracing method. If the phantom is in liquid, the image of the phantom can be distorted since the light passes through a convex liquid-vapor interface. Because of the optical distortion effect, the projection matrix used to reconstruct a 3D field should be supplemented by the revision ray, instead of the original projection ray. The revision ray can be obtained from the refraction ray occurring on the surface of the liquid. As a result, the error on the reconstruction field of the phantom could be reduced using the developed optical correction method. In addition, the developed optical method was applied to a Taylor cone which was caused by the high voltage between the droplet and the substrate. PMID:27082349

  7. Three-dimensional volumetric human meibomian gland investigation using polarization-sensitive optical coherence tomography.

    PubMed

    Ju, Myeong Jin; Shin, Jun Geun; Hoshi, Sujin; Yasuno, Yoshiaki; Lee, Byeong Ha; Tang, Shuo; Eom, Tae Joong

    2014-03-01

    In this study, polarization-sensitive optical coherence tomography (PS-OCT) capable of providing polarization contrasts such as phase retardation and degree of polarization uniformity (DOPU) was used for visualizing human meibomian glands (MGs) and investigating morphological characteristics of them. Especially, with the help of the DOPU contrast, MGs were exclusively extracted from the volumetric OCT image. In vivo PS-OCT measurements were performed on the upper eyelids of different age groups. From these measurements, different age-dependent aspects of the MG structure were also observed. Based on these observations, it can be inferred that the PS-OCT system has the potential for clinical diagnosis and investigation of MG-related dry eye diseases like MG dysfunction (MGD) and acinar atrophy.

  8. Three Dimensional Motion Tracking for High Resolution Optical Microscopy, in vivo

    PubMed Central

    Pursley, Randall; Pohida, Thomas J.; Glancy, Brian; Taylor, Joni; Chess, David; Kellman, Peter; Xue, Hui; Balaban, Robert S.

    2013-01-01

    When conducting optical imaging experiments, in vivo, the signal to noise ratio and effective spatial and temporal resolution is fundamentally limited by physiological motion of the tissue. A 3-dimensional motion tracking scheme, using a multi-photon excitation microscope with a resonant galvanometer, (512×512 pixels at 33 frames/sec) is described to overcome physiological motion, in vivo. The use of commercially available graphical processing units permitted the rapid 3-dimensional cross-correlation of sequential volumes to detect displacements and adjust tissue position to track motions in near real-time. Motion phantom tests maintained micron resolution with displacement velocities of up to 200 μm/min, well within the drift observed in many biological tissues under physiologically relevant conditions. In vivo experiments on mouse skeletal muscle using the capillary vasculature with luminal dye as a displacement reference revealed an effective and robust method of tracking tissue motion to enable (1) signal averaging over time without compromising resolution, and (2) tracking of cellular regions during a physiological perturbation. PMID:22582797

  9. High-Speed GPU-Based Fully Three-Dimensional Diffuse Optical Tomographic System

    PubMed Central

    Saikia, Manob Jyoti; Kanhirodan, Rajan; Mohan Vasu, Ram

    2014-01-01

    We have developed a graphics processor unit (GPU-) based high-speed fully 3D system for diffuse optical tomography (DOT). The reduction in execution time of 3D DOT algorithm, a severely ill-posed problem, is made possible through the use of (1) an algorithmic improvement that uses Broyden approach for updating the Jacobian matrix and thereby updating the parameter matrix and (2) the multinode multithreaded GPU and CUDA (Compute Unified Device Architecture) software architecture. Two different GPU implementations of DOT programs are developed in this study: (1) conventional C language program augmented by GPU CUDA and CULA routines (C GPU), (2) MATLAB program supported by MATLAB parallel computing toolkit for GPU (MATLAB GPU). The computation time of the algorithm on host CPU and the GPU system is presented for C and Matlab implementations. The forward computation uses finite element method (FEM) and the problem domain is discretized into 14610, 30823, and 66514 tetrahedral elements. The reconstruction time, so achieved for one iteration of the DOT reconstruction for 14610 elements, is 0.52 seconds for a C based GPU program for 2-plane measurements. The corresponding MATLAB based GPU program took 0.86 seconds. The maximum number of reconstructed frames so achieved is 2 frames per second. PMID:24891848

  10. Analyzing three-dimensional ultrastructure of human cervical tissue using optical coherence tomography

    PubMed Central

    Gan, Yu; Yao, Wang; Myers, Kristin. M; Vink, Joy Y.; Wapner, Ronald. J.; Hendon, Christine P.

    2015-01-01

    During pregnancy, the uterine cervix is the mechanical barrier that prevents delivery of a fetus. The underlying cervical collagen ultrastructure, which influences the overall mechanical properties of the cervix, plays a role in maintaining a successful pregnancy until term. Yet, not much is known about this collagen ultrastructure in pregnant and nonpregnant human tissue. We used optical coherence tomography to investigate the directionality and dispersion of collagen fiber bundles in the human cervix. An image analysis tool has been developed, combining a stitching method with a fiber orientation measurement, to study axially sliced cervix samples. This tool was used to analyze the ultrastructure of ex-vivo pregnant and non-pregnant hysterectomy tissue samples taken at the internal os, which is the region of the cervix adjacent to the uterus. With this tool, directionality maps of collagen fiber bundles and dispersion of collagen fiber orientation were analyzed. It was found that that the overall preferred directionality of the collagen fibers for both the nonpregnant and pregnant samples were circling around the inner cervical canal. Pregnant samples showed greater dispersion than non-pregnant samples. Lastly, we observed regional differences in collagen fiber dispersion. Fibers closer to the inner canal showed more dispersion than the fibers on the radial edges. PMID:25908997

  11. Three-dimensional photonic crystal fluorinated tin oxide (FTO) electrodes : synthesis and optical and electrical properties.

    SciTech Connect

    Yang, Z.; Gao, S.; Li, W.; Vlasko-Vlasov, V.; Welp, U.; Kwok, W.-K.; Xu, T.

    2011-04-01

    Photovoltaic (PV) schemes often encounter a pair of fundamentally opposing requirements on the thickness of semiconductor layer: a thicker PV semiconductor layer provides enhanced optical density, but inevitably increases the charge transport path length. An effective approach to solve this dilemma is to enhance the interface area between the terminal electrode, i.e., transparent conducting oxide (TCO) and the semiconductor layer. As such, we report a facile, template-assisted, and solution chemistry-based synthesis of 3-dimensional inverse opal fluorinated tin oxide (IO-FTO) electrodes. Synergistically, the photonic crystal structure possessed in the IO-FTO exhibits strong light trapping capability. Furthermore, the electrical properties of the IO-FTO electrodes are studied by Hall effect and sheet resistance measurement. Using atomic layer deposition method, an ultrathin TiO{sub 2} layer is coated on all surfaces of the IO-FTO electrodes. Cyclic voltammetry study indicates that the resulting TiO{sub 2}-coated IO-FTO shows excellent potentials as electrodes for electrolyte-based photoelectrochemical solar cells.

  12. Quadcopter control in three-dimensional space using a noninvasive motor imagery based brain-computer interface

    PubMed Central

    LaFleur, Karl; Cassady, Kaitlin; Doud, Alexander; Shades, Kaleb; Rogin, Eitan; He, Bin

    2013-01-01

    Objective At the balanced intersection of human and machine adaptation is found the optimally functioning brain-computer interface (BCI). In this study, we report a novel experiment of BCI controlling a robotic quadcopter in three-dimensional physical space using noninvasive scalp EEG in human subjects. We then quantify the performance of this system using metrics suitable for asynchronous BCI. Lastly, we examine the impact that operation of a real world device has on subjects’ control with comparison to a two-dimensional virtual cursor task. Approach Five human subjects were trained to modulate their sensorimotor rhythms to control an AR Drone navigating a three-dimensional physical space. Visual feedback was provided via a forward facing camera on the hull of the drone. Individual subjects were able to accurately acquire up to 90.5% of all valid targets presented while travelling at an average straight-line speed of 0.69 m/s. Significance Freely exploring and interacting with the world around us is a crucial element of autonomy that is lost in the context of neurodegenerative disease. Brain-computer interfaces are systems that aim to restore or enhance a user’s ability to interact with the environment via a computer and through the use of only thought. We demonstrate for the first time the ability to control a flying robot in the three-dimensional physical space using noninvasive scalp recorded EEG in humans. Our work indicates the potential of noninvasive EEG based BCI systems to accomplish complex control in three-dimensional physical space. The present study may serve as a framework for the investigation of multidimensional non-invasive brain-computer interface control in a physical environment using telepresence robotics. PMID:23735712

  13. Fast segmentation and high-quality three-dimensional volume mesh creation from medical images for diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Jermyn, Michael; Ghadyani, Hamid; Mastanduno, Michael A.; Turner, Wes; Davis, Scott C.; Dehghani, Hamid; Pogue, Brian W.

    2013-08-01

    Multimodal approaches that combine near-infrared (NIR) and conventional imaging modalities have been shown to improve optical parameter estimation dramatically and thus represent a prevailing trend in NIR imaging. These approaches typically involve applying anatomical templates from magnetic resonance imaging/computed tomography/ultrasound images to guide the recovery of optical parameters. However, merging these data sets using current technology requires multiple software packages, substantial expertise, significant time-commitment, and often results in unacceptably poor mesh quality for optical image reconstruction, a reality that represents a significant roadblock for translational research of multimodal NIR imaging. This work addresses these challenges directly by introducing automated digital imaging and communications in medicine image stack segmentation and a new one-click three-dimensional mesh generator optimized for multimodal NIR imaging, and combining these capabilities into a single software package (available for free download) with a streamlined workflow. Image processing time and mesh quality benchmarks were examined for four common multimodal NIR use-cases (breast, brain, pancreas, and small animal) and were compared to a commercial image processing package. Applying these tools resulted in a fivefold decrease in image processing time and 62% improvement in minimum mesh quality, in the absence of extra mesh postprocessing. These capabilities represent a significant step toward enabling translational multimodal NIR research for both expert and nonexpert users in an open-source platform.

  14. Synchronous triple-optical-path digital speckle pattern interferometry with fast discrete curvelet transform for measuring three-dimensional displacements

    NASA Astrophysics Data System (ADS)

    Gu, Guoqing; Wang, Kaifu; Wang, Yanfang; She, Bin

    2016-06-01

    Digital speckle pattern interferometry (DSPI) is a well-established and widely used optical measurement technique for obtaining qualitative as well as quantitative measurements of objects deformation. The simultaneous measurement of an object's surface displacements in three dimensions using DSPI is of great interest. This paper presents a triple-optical-path DSPI based method for the simultaneous and independent measurement of three-dimensional (3D) displacement fields. In the proposed method, in-plane speckle interferometers with dual-observation geometry and an out-of-plane interferometer are optimally combined to construct an integrated triple-optical-path DSPI system employing the phase shift technique, which uses only a single laser source and three cameras. These cameras are placed along a single line to synchronously capture real-time visible speckle fringe patterns in three dimensions. In addition, a pre-filtering method based on the fast discrete curvelet transform (FDCT) is utilized for denoising the obtained wrapped phase patterns to improve measurement accuracy. Finally, the simultaneous measurement of the 3D displacement fields of a simple beam and a composite laminated plate respectively subjected to three-point and single-point bend loading are investigated to validate the feasibility and effectiveness of the proposed method.

  15. Transmission through a scalar wave three-dimensional electromagnetic metamaterial and the implication for polarization control.

    PubMed

    Shin, Jonghwa; Shen, Jung-Tsung; Fan, Shanhui

    2010-03-01

    An interweaving-conductor metamaterial (ICM) is a metamaterial composed of multiple, interlocking, conducting networks. It exhibits unusual optical properties in the low-frequency linear-dispersion regime. In particular, two-network ICM supports only one, non-dispersive mode in the low frequency range, and is best described as an effective medium supporting a scalar wave in full three dimensions. We explore the light transmission properties of such a metamaterial, and the implications of a scalar wave medium for polarization control. Polarizers and polarization rotators with subwavelength sizes are numerically demonstrated.

  16. [Three-dimensional optical coherence tomography for evaluating the retinal architecture before and after surgery for vitreomacular traction.

    PubMed

    Georgopoulos, M; Geitzenauer, W; Ahlers, C; Simader, C; Scholda, C; Schmidt-Erfurth, U

    2008-03-30

    PURPOSE: To investigate the morphology of the vitreoretinal interface before and after delamination of epiretinal membranes using three-dimensional volumetric high-resolution optical coherence tomography (HROCT). METHODS: Extension and intensity of vitreomacular traction due to epiretinal membranes (ERM) and the architecture of retinal layers in 14 eyes of 14 patients were evaluated preoperatively using high-resolution raster scanning OCT (Cirrus prototype, resulting in a 6x6-mm field, 2 mm in depth). Additionally, stratus OCT, visual acuity testing, and fundus photography were performed. Standardized prospective follow-up was done continuously at 1, 4, and 7 days and 1 and 3 months postoperatively. RESULTS: The ERM appeared tightly adherent to the retinal surface in 85% of cases, but nevertheless could be differentiated from the retinal surface in 100%. Vertical traction forces from the ERM to the intraretinal layers were found in 93% of cases. Structural alteration of the retina was seen neither immediately following surgery nor during follow-up. After a mean of 4 weeks, the retinal structural integrity had recovered with resolution of the traction-induced deviations seen preoperatively. Mean preoperative visual acuity increased from 0.4+/-0.2 Snellen preoperatively to 0.5+/-0.2 Snellen after 3 months. Mean retinal thickness decreased from 482+/-84 mum to 328+/-80 mum after 3 months (HROCT). CONCLUSIONS: Three-dimensional HROCT imaging enables unprecedented in vivo identification of the extension and dynamics of epiretinal traction. Epiretinal membranes are clearly delineated in the en face view, and the distribution of traction forces throughout the intraretinal layers is identified down to the level of the retinal pigment epithelium. During follow-up, quantification of substantial release in retinal traction was possible and correlated to conventional OCT findings.

  17. Tissue-culture light sheet fluorescence microscopy (TC-LSFM) allows long-term imaging of three-dimensional cell cultures under controlled conditions.

    PubMed

    Pampaloni, Francesco; Berge, Ulrich; Marmaras, Anastasios; Horvath, Peter; Kroschewski, Ruth; Stelzer, Ernst H K

    2014-10-01

    Fluorescence long-term imaging of cellular processes in three-dimensional cultures requires the control of media supply, temperature, and pH, as well as minimal photodamage. We describe a system based on a light sheet fluorescence microscope (LSFM), which is optimized for long-term, multi-position imaging of three-dimensional in-gel cell cultures. The system integrates a stable culture condition control system in the optical path of the light-sheet microscope. A further essential element is a biocompatible agarose container suitable for the LSFM, in which any cell type can be cultured in different gel matrices. The TC-LSFM allows studying any in vitro cultured cell type reacting to, dividing in, or migrating through a three-dimensional extracellular matrix (ECM) gel. For this reason we called it "tissue culture-LSFM" (TC-LSFM). The TC-LSFM system allows fast imaging at multiple locations within a millimeter-sized ECM gel. This increases the number of analyzed events and allows testing population effects. As an example, we show the maturation of a cyst of MDCK (canine kidney epithelial) cells over a period of three days. Moreover, we imaged, tracked, and analyzed MDCK cells during the first five days of cell aggregate formation and discovered a remarkable heterogeneity in cell cycle lengths and an interesting cell death pattern. Thus, TC-LSFM allows performing new long-term assays assessing cellular behavior in three-dimensional ECM-gel cultures. For example migration, invasion or differentiation in epithelial cell systems, stem cells, as well as cancer cells can be investigated.

  18. Metallo-dielectric core-shell nanospheres as building blocks for optical three-dimensional isotropic negative-index metamaterials

    NASA Astrophysics Data System (ADS)

    Paniagua-Domínguez, R.; López-Tejeira, F.; Marqués, R.; Sánchez-Gil, J. A.

    2011-12-01

    Materials showing electromagnetic properties that are not attainable in naturally occurring media, so-called metamaterials, have been lately, and still are, among the most active topics in optical and materials physics and engineering. Among these properties, one of the most attractive ones is the sub-diffraction resolving capability predicted for media having an index of refraction of -1. Here, we propose a fully three-dimensional, isotropic metamaterial with strong electric and magnetic responses in the optical regime, based on spherical metallo-dielectric core-shell nanospheres. The magnetic response stems from the lowest, magnetic-dipole resonance of the dielectric shell with a high refractive index, and can be tuned to coincide with the plasmon resonance of the metal core, responsible for the electric response. Since the response does not originate from coupling between structures, no particular periodic arrangement needs to be imposed. Moreover, due to the geometry of the constituents, the metamaterial is intrinsically isotropic and polarization independent. It could be realized with current fabrication techniques with materials such as silver (core) and silicon or germanium (shell). For these particular realistic designs, the metamaterials present a negative index in the range of 1.2-1.55 μm.

  19. Three-dimensional reconstruction of flame temperature and emissivity distribution using optical tomographic and two-colour pyrometric techniques

    NASA Astrophysics Data System (ADS)

    Moinul Hossain, Md; Lu, Gang; Sun, Duo; Yan, Yong

    2013-07-01

    This paper presents an experimental investigation, visualization and validation in the three-dimensional (3D) reconstruction of flame temperature and emissivity distributions by using optical tomographic and two-colour pyrometric techniques. A multi-camera digital imaging system comprising eight optical imaging fibres and two RGB charged-couple device (CCD) cameras are used to acquire two-dimensional (2D) images of the flame simultaneously from eight equiangular directions. A combined logical filtered back-projection (LFBP) and simultaneous iterative reconstruction and algebraic reconstruction technique (SART) algorithm is utilized to reconstruct the grey-level intensity of the flame for the two primary colour (red and green) images. The temperature distribution of the flame is then determined from the ratio of the reconstructed grey-level intensities and the emissivity is estimated from the ratio of the grey level of a primary colour image to that of a blackbody source at the same temperature. The temperature measurement of the system was calibrated using a blackbody furnace as a standard temperature source. Experimental work was undertaken to validate the flame temperature obtained by the imaging system against that obtained using high-precision thermocouples. The difference between the two measurements is found no greater than ±9%. Experimental results obtained on a laboratory-scale propane fired combustion test rig demonstrate that the imaging system and applied technical approach perform well in the reconstruction of the 3D temperature and emissivity distributions of the sooty flame.

  20. A novel backlight unit for volume-holographic optical elements-based time-multiplexed three-dimensional displays

    NASA Astrophysics Data System (ADS)

    Kim, Byung-Mok; Hwang, Yong-Seok; Kim, Eun-Soo

    2015-11-01

    In volume-holographic optical elements (VHOEs)-based time-sequential three-dimensional (3-D) displays, two reference beams generated from a backlight unit (BLU) illuminate VHOEs, and from which object beams satisfying the Brag condition are then diffracted. These beams form a pair of alternating light fields for stereo 3-D view. Since this system operates based on diffraction optics, its performance highly depends on the degrees of collimation and uniformity of the reference beams. Thus, a new BLU system to generate uniformly-collimated reference beams for the VHOEs-based 3-D display is proposed by combined use of a light-guide-plate (LGP) grooved with an array of angle-variant flat-top prisms, and two LED light sources attached with reflection-type beam collimators. Simulation results with LightTools 7.1 show that the average full-width at half maximum (FWHM), backshift ratio and intensity uniformity of the LGP output beam of the proposed system have been significantly reduced down to 2.8° and 0.4%, and increased up to 90.9%, respectively, from the values of 51.8°, 26.5% and 24.5% of the conventional system. They represent 18.5-, 66.3- and 3.7-fold improvements of those values in the proposed system, respectively. These successful results confirm the feasibility of the proposed system in the practical VHOEs-based 3-D display.

  1. Optical topography guided semi-three-dimensional diffuse optical tomography for a multi-layer model of occipital cortex: a pilot methodological study

    NASA Astrophysics Data System (ADS)

    Ding, Hao; Zhang, Yao; He, Jie; Zhao, Huijuan; Gao, Feng

    2016-03-01

    In this paper, an optical topography (OT) guided diffuse optical tomography (DOT) scheme is developed for functional imaging of the occipital cortex. The method extends the previously proposed semi-three-dimensional DOT methodology to reconstruction of two-dimensional extracerebral and cerebral images using a visual cortex oriented five-layered slab geometry, and incorporate the OT localization regularization in the cerebral reconstruction to achieve enhanced quantitative accuracy and spatial resolution. We validate the methodology using simulated data and demonstrate its merits in comparison to the standalone OT and DOT.

  2. Phenomenological aspects of quasi-stationary controlled and uncontrolled three-dimensional flow separations. [in relation to aircraft design considerations and swept wings

    NASA Technical Reports Server (NTRS)

    Peake, D. J.

    1978-01-01

    Quasi-steady three dimensional separated flows about bodies of large fineness ratio operating at large angles of incidence or yaw are discussed. The general character of the three dimensional attached boundary layer, the concept of limiting streamlines, and the physics of three dimensional separation and reattachment are among the factors considered. Specific examples are given. The advantages of swept, sharp edges that generate controlled (or fixed) three dimensional flow separations on a vehicle, due to the qualitatively unchanging flow field developed throughout the range of flight conditions, are emphasized.

  3. Real-time three-dimensional optical coherence tomography image-guided core-needle biopsy system

    PubMed Central

    Kuo, Wei-Cheng; Kim, Jongsik; Shemonski, Nathan D.; Chaney, Eric J.; Spillman, Darold R.; Boppart, Stephen A.

    2012-01-01

    Advances in optical imaging modalities, such as optical coherence tomography (OCT), enable us to observe tissue microstructure at high resolution and in real time. Currently, core-needle biopsies are guided by external imaging modalities such as ultrasound imaging and x-ray computed tomography (CT) for breast and lung masses, respectively. These image-guided procedures are frequently limited by spatial resolution when using ultrasound imaging, or by temporal resolution (rapid real-time feedback capabilities) when using x-ray CT. One feasible approach is to perform OCT within small gauge needles to optically image tissue microstructure. However, to date, no system or core-needle device has been developed that incorporates both three-dimensional OCT imaging and tissue biopsy within the same needle for true OCT-guided core-needle biopsy. We have developed and demonstrate an integrated core-needle biopsy system that utilizes catheter-based 3-D OCT for real-time image-guidance for target tissue localization, imaging of tissue immediately prior to physical biopsy, and subsequent OCT imaging of the biopsied specimen for immediate assessment at the point-of-care. OCT images of biopsied ex vivo tumor specimens acquired during core-needle placement are correlated with corresponding histology, and computational visualization of arbitrary planes within the 3-D OCT volumes enables feedback on specimen tissue type and biopsy quality. These results demonstrate the potential for using real-time 3-D OCT for needle biopsy guidance by imaging within the needle and tissue during biopsy procedures. PMID:22741064

  4. Dual-wavelength optical-resolution photoacoustic microscopy for cells with gold nanoparticle bioconjugates in three-dimensional cultures

    NASA Astrophysics Data System (ADS)

    Lee, Po-Yi; Liu, Wei-Wen; Chen, Shu-Ching; Li, Pai-Chi

    2016-03-01

    Three-dimensional (3D) in vitro models bridge the gap between typical two-dimensional cultures and in vivo conditions. However, conventional optical imaging methods such as confocal microscopy and two-photon microscopy cannot accurately depict cellular processing in 3D models due to limited penetration of photons. We developed a dualwavelength optical-resolution photoacoustic microscopy (OR-PAM), which provides sufficient penetration depth and spatial resolution, for studying CD8+ cytotoxic T lymphocytes (CTLs) trafficking in an in vitro 3D tumor microenvironment. CTLs play a cardinal role in host defense against tumor. Efficient trafficking of CTLs to the tumor microenvironment is a critical step for cancer immunotherapy. For the proposed system, gold nanospheres and indocyanine green (ICG) have been remarkable choices for contrast agents for photoacoustic signals due to their excellent biocompatibility and high optical absorption. With distinct absorption spectrums, targeted cells with gold nanospheres and ICG respectively can be identified by switching 523-nm and 800-nm laser irradiation. Moreover, we use an x-y galvanometer scanner to obtain high scanning rate. In the developed system, lateral and axial resolutions were designed at 1.6 μm and 5 μm, respectively. We successfully showed that dual-spectral OR-PAM can map either the distribution of CTLs with gold nanospheres at a visible wavelength of 523 nm or the 3D structure of tumor spheres with ICG in an in vitro 3D microenvironment. Our OR-PAM can provide better biological relevant information in cellular interaction and is potential for preclinical screening of anti-cancer drugs.

  5. Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

    NASA Astrophysics Data System (ADS)

    Román, Jesús; Cabañas, María Victoria; Peña, Juan; Vallet-Regí, María

    2011-08-01

    Hydrogels (gellan or agarose) reinforced with nanocrystalline carbonated hydroxyapatite (nCHA) were prepared by the GELPOR3D technique. This simple method is characterized by compositional flexibility; it does not require expensive equipment, thermal treatment, or aggressive or toxic solvents, and yields a three-dimensional (3D) network of interconnected pores 300-900 μm in size. In addition, an interconnected porosity is generated, yielding a hierarchical porous architecture from the macro to the molecular scale. This porosity depends on both the drying/preservation technology (freeze drying or oven drying at 37 circleC) and on the content and microstructure of the reinforcing ceramic. For freeze-dried samples, the porosities were approximately 30, 66 and below 3% for pore sizes of 600-900 μm, 100-200 μm and 50-100 nm, respectively. The pore structure depends much on the ceramic content, so that higher contents lead to the disappearance of the characteristic honeycomb structure observed in low-ceramic scaffolds and to a lower fraction of the 100-200-μm-sized pores. The nature of the hydrogel did not affect the pore size distribution but was crucial for the behavior of the scaffolds in a hydrated medium: gellan-containing scaffolds showed a higher swelling degree owing to the presence of more hydrophilic groups.

  6. Three-Dimensional Mapping of Microenvironmental Control of Methyl Rotational Barriers

    SciTech Connect

    Hembree, William I; Baudry, Jerome Y

    2011-01-01

    Sterical (van der Waals-induced) rotational barriers of methyl groups are investigated theoretically, using ab initio and empirical force field calculations, for various three-dimensional microenvironmental conditions around the methyl group rotator of a model neopentane molecule. The destabilization (reducing methyl rotational barriers) or stabilization (increasing methyl rotational barriers) of the staggered conformation of the methyl rotator depends on a combination of microenvironmental contributions from (i) the number of atoms around the rotator, (ii) the distance between the rotator and the microenvironmental atoms, and (iii) the dihedral angle between the stator, rotator, and molecular environment around the rotator. These geometrical criteria combine their respective effects in a linearly additive fashion, with no apparent cooperative effects, and their combination in space around a rotator may increase, decrease, or leave the rotator s rotational barrier unmodified. This is exemplified in a geometrical analysis of the alanine dipeptide crystal where microenvironmental effects on methyl rotators barrier of rotation fit the geometrical mapping described in the neopentane model.

  7. Three-dimensionally modulated anisotropic structure for diffractive optical elements created by one-step three-beam polarization holographic photoalignment

    NASA Astrophysics Data System (ADS)

    Kawai, Kotaro; Sakamoto, Moritsugu; Noda, Kohei; Sasaki, Tomoyuki; Kawatsuki, Nobuhiro; Ono, Hiroshi

    2016-03-01

    A diffractive optical element with a three-dimensional liquid crystal (LC) alignment structure for advanced control of polarized beams was fabricated by a highly efficient one-step photoalignment method. This study is of great significance because different two-dimensional continuous and complex alignment patterns can be produced on two alignment films by simultaneously irradiating an empty glass cell composed of two unaligned photocrosslinkable polymer LC films with three-beam polarized interference beam. The polarization azimuth, ellipticity, and rotation direction of the diffracted beams from the resultant LC grating widely varied depending on the two-dimensional diffracted position and the polarization states of the incident beams. These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus.

  8. Three-dimensional dynamics of a fermionic Mott wedding-cake in clean and disordered optical lattices

    PubMed Central

    Kartsev, A.; Karlsson, D.; Privitera, A.; Verdozzi, C.

    2013-01-01

    Non-equilibrium quantum phenomena are ubiquitous in nature. Yet, theoretical predictions on the real-time dynamics of many-body quantum systems remain formidably challenging, especially for high dimensions, strong interactions or disordered samples. Here we consider a notable paradigm of strongly correlated Fermi systems, the Mott phase of the Hubbard model, in a setup resembling ultracold-gases experiments. We study the three-dimensional expansion of a cloud into an optical lattice after removing the confining potential. We use time-dependent density-functional theory combined with dynamical mean-field theory, considering interactions below and above the Mott threshold, as well as disorder effects. At strong coupling, we observe multiple timescales in the melting of the Mott wedding-cake structure, as the Mott plateau persist orders of magnitude longer than the band insulating core. We also show that disorder destabilises the Mott plateau and that, compared to a clean setup, localisation can decrease, creating an interesting dynamic crossover during the expansion. PMID:23999144

  9. Three-dimensional registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation.

    PubMed

    Prabhu, David; Mehanna, Emile; Gargesha, Madhusudhana; Brandt, Eric; Wen, Di; van Ditzhuijzen, Nienke S; Chamie, Daniel; Yamamoto, Hirosada; Fujino, Yusuke; Alian, Ali; Patel, Jaymin; Costa, Marco; Bezerra, Hiram G; Wilson, David L

    2016-04-01

    Evidence suggests high-resolution, high-contrast, [Formula: see text] intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and three-dimensional (3-D) registration methods to provide validation of IVOCT pullback volumes using microscopic, color, and fluorescent cryo-image volumes with optional registered cryo-histology. A specialized registration method matched IVOCT pullback images acquired in the catheter reference frame to a true 3-D cryo-image volume. Briefly, an 11-parameter registration model including a polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition. Virtual catheter parameters were optimized to maximize cryo and IVOCT lumen overlap. Multiple assessments suggested that the registration error was better than the [Formula: see text] spacing between IVOCT image frames. Tests on a digital synthetic phantom gave a registration error of only [Formula: see text] (signed distance). Visual assessment of randomly presented nearby frames suggested registration accuracy within 1 IVOCT frame interval ([Formula: see text]). This would eliminate potential misinterpretations confronted by the typical histological approaches to validation, with estimated 1-mm errors. The method can be used to create annotated datasets and automated plaque classification methods and can be extended to other intravascular imaging modalities.

  10. Mathieu Function Solutions for the Photoacoustic Effect in Two- and Three-Dimensional Structures and Optical Traps

    NASA Astrophysics Data System (ADS)

    Wu, Binbin; Diebold, Gerald J.

    2012-11-01

    The wave equation for the photoacoustic effect in a three-dimensional spherically symmetric, or two-dimensional structure where the compressibility or density varies sinusoidally in space reduces to an inhomogeneous Mathieu equation. As such, exact solutions for the photoacoustic pressure can be found in terms of either Mathieu functions, integer order Mathieu functions, or fractional order Mathieu functions, the last of these being of importance for problems pertaining to structures of finite dimensions. Here, frequency domain solutions are given for a spherical structure with material properties varying radially, and a two-dimensional structure with material variations in one direction. Solutions for the acoustic pressure are found that give closed form expressions for the resonance frequencies. It is also shown that Mathieu functions give solutions for the motion of an optically levitated sphere trapped in an intensity modulated, Gaussian laser beam. By determining the frequencies at which the motions of the sphere are largest, that is, where the Mathieu functions become unstable, it is shown that the trap can act to determine the radiation force relative to the gravitational force on the sphere.

  11. Assessment of chronic wounds by three-dimensional optical imaging based on integrating geometrical, chromatic, and thermal data.

    PubMed

    Barone, S; Paoli, A; Razionale, A V

    2011-02-01

    Chronic wounds represent a particular debilitating health care problem, mainly affecting elderly people. A full and correct diagnosis of tissue damage should be carried out considering both dimensional, chromatic, and thermal parameters. A great variety of methods have been proposed with the aim of producing objective assessment of skin lesions, but none of the existing technologies seem to be robust enough to work for all ulcer typologies. This paper describes an innovative and non-invasive system that allows the automatic measurement of non-healing chronic wounds. The methodology involves the integration of a three-dimensional (3D) optical scanner, based on a structured light approach, with a thermal imager. The system enables the acquisition of geometrical data, which are directly related to chromatic and temperature patterns through a mapping procedure. Damaged skin areas are detected by combining visible and thermal imaging. This approach allows for the automatic measurement of extension and depth of ulcers, even in the absence of significant and well-defined chromatic patterns. The proposed technology has been tested in the measurement of ulcers on human legs. Clinical tests have demonstrated the effectiveness of this methodology in supporting medical experts for the assessment of chronic wounds. PMID:21428152

  12. Microvascular anastomosis guidance and evaluation using real-time three-dimensional Fourier-domain Doppler optical coherence tomography

    PubMed Central

    Ibrahim, Zuhaib; Tong, Dedi; Zhu, Shan; Mao, Qi; Pang, John; Andrew Lee, Wei Ping; Brandacher, Gerald; Kang, Jin U.

    2013-01-01

    Abstract. Vascular and microvascular anastomoses are critical components of reconstructive microsurgery, vascular surgery, and transplant surgery. Intraoperative surgical guidance using a surgical imaging modality that provides an in-depth view and three-dimensional (3-D) imaging can potentially improve outcome following both conventional and innovative anastomosis techniques. Objective postoperative imaging of the anastomosed vessel can potentially improve the salvage rate when combined with other clinical assessment tools, such as capillary refill, temperature, blanching, and skin turgor. Compared to other contemporary postoperative monitoring modalities—computed tomography angiograms, magnetic resonance (MR) angiograms, and ultrasound Doppler—optical coherence tomography (OCT) is a noninvasive high-resolution (micron-level), high-speed, 3-D imaging modality that has been adopted widely in biomedical and clinical applications. For the first time, to the best of our knowledge, the feasibility of real-time 3-D phase-resolved Doppler OCT (PRDOCT) as an assisted intra- and postoperative imaging modality for microvascular anastomosis of rodent femoral vessels is demonstrated, which will provide new insights and a potential breakthrough to microvascular and supermicrovascular surgery. PMID:23856833

  13. Analysis of the Outer Retina Reconstructed by High-Resolution, Three-Dimensional Spectral Domain Optical Coherence Tomography

    PubMed Central

    Kaluzny, Jakub J.; Wojtkowski, Maciej; Sikorski, Bartosz L.; Szkulmowski, Maciej; Szkulmowska, Anna; Bajraszewski, Tomasz; Fujimoto, James G.; Duker, Jay S.; Schuman, Joel S.; Kowalczyk, Andrzej

    2009-01-01

    Background and Objective A retrospective cross-sectional study was conducted to demonstrate an analysis of an outer retinal layer reconstructed by the three-dimensional and high-speed spectral domain optical coherence tomography (SD-OCT) instrument. Patients and Methods New measurement protocols for SD-OCT and methods of analysis and visualization of the individual segmented retinal layer reconstructed by SD-OCT were proposed. Three contour maps representing mutual distances between the basal part of the retinal pigment epithelium, the junction between the inner and outer segments of photoreceptors, and a reference contour representing the shape of a healthy retina were introduced. Results The analysis of the outer retina was performed on pathological eyes. Three cases of central serous chorioretinopathy, age-related macular degeneration, and acute zonal occult outer retinopathy are demonstrated. Conclusion Three contour maps reconstructed for clinical cases demonstrate high variability of observed patterns depending on analyzed pathology. The authors believe this can help to present OCT data simultaneously in a more comprehensive and convenient way to assist in everyday clinical diagnosis. PMID:19320297

  14. Optical fiber tip with point light source of SPPs driven by three-dimensional nanostructured asymmetric metal-insulator-metal layer cap

    NASA Astrophysics Data System (ADS)

    Oshikane, Yasushi; Murai, Kensuke; Nakano, Motohiro

    2015-09-01

    Numerical analysis of three dimensional optical electro-magnetic field in a circular-truncated conical optical fiber covered by asymmetric MIM structure has been performed by a commercial finite element method package, COMSOL Multiphysics coupled with Wave Optics Module. The outermost thick metallic layer has twin nano-hole, and the waveguiding twin-hole could draw surface plasmon polaritions (SPPs) excited in the MIM structure to the surface. Finally the guided two SPPs could unite each other and may create a single bright spot. The systematic simulation is continuing, and the results will give us valuable counsel for control of surface plasmon polaritons (SPPs) appearing around the MIM structure and twin nano-hole. (1) Optimal design of the 3D FEM model for 8-core Xeon server and rational approach for the FEM analysis, (2) behavior of SPPs affected by wavelength and polarization of light travel through fiber, (3) change in excitation condition of SPPs caused by shape of the MIM structure and twin-hole, (4) effectiveness of additional nanostructures that are aimed at focusing control of two SPPs come out from the corners of twin-hole, (5) scanning ability of the MIM/twin-hole probe at nanostructured sample surface (i.e. amount of forward and backward scattering of SPPs) will be presented and discussed. Several FIBed prototypes and their characteristic of light emission will also reported.

  15. Impact angle constrained three-dimensional integrated guidance and control for STT missile in the presence of input saturation.

    PubMed

    Wang, Sen; Wang, Weihong; Xiong, Shaofeng

    2016-09-01

    Considering a class of skid-to-turn (STT) missile with fixed target and constrained terminal impact angles, a novel three-dimensional (3D) integrated guidance and control (IGC) scheme is proposed in this paper. Based on coriolis theorem, the fully nonlinear IGC model without the assumption that the missile flies heading to the target at initial time is established in the three-dimensional space. For this strict-feedback form of multi-variable system, dynamic surface control algorithm is implemented combining with extended observer (ESO) to complete the preliminary design. Then, in order to deal with the problems of the input constraints, a hyperbolic tangent function is introduced to approximate the saturation function and auxiliary system including a Nussbaum function established to compensate for the approximation error. The stability of the closed-loop system is proven based on Lyapunov theory. Numerical simulations results show that the proposed integrated guidance and control algorithm can ensure the accuracy of target interception with initial alignment angle deviation and the input saturation is suppressed with smooth deflection curves.

  16. Size-controlled conformal nanofabrication of biotemplated three-dimensional TiO2 and ZnO nanonetworks

    PubMed Central

    Ceylan, Hakan; Ozgit-Akgun, Cagla; Erkal, Turan S.; Donmez, Inci; Garifullin, Ruslan; Tekinay, Ayse B.; Usta, Hakan; Biyikli, Necmi; Guler, Mustafa O.

    2013-01-01

    A solvent-free fabrication of TiO2 and ZnO nanonetworks is demonstrated by using supramolecular nanotemplates with high coating conformity, uniformity, and atomic scale size control. Deposition of TiO2 and ZnO on three-dimensional nanofibrous network template is accomplished. Ultrafine control over nanotube diameter allows robust and systematic evaluation of the electrochemical properties of TiO2 and ZnO nanonetworks in terms of size-function relationship. We observe hypsochromic shift in UV absorbance maxima correlated with decrease in wall thickness of the nanotubes. Photocatalytic activities of anatase TiO2 and hexagonal wurtzite ZnO nanonetworks are found to be dependent on both the wall thickness and total surface area per unit of mass. Wall thickness has effect on photoexcitation properties of both TiO2 and ZnO due to band gap energies and total surface area per unit of mass. The present work is a successful example that concentrates on nanofabrication of intact three-dimensional semiconductor nanonetworks with controlled band gap energies. PMID:23892593

  17. Impact angle constrained three-dimensional integrated guidance and control for STT missile in the presence of input saturation.

    PubMed

    Wang, Sen; Wang, Weihong; Xiong, Shaofeng

    2016-09-01

    Considering a class of skid-to-turn (STT) missile with fixed target and constrained terminal impact angles, a novel three-dimensional (3D) integrated guidance and control (IGC) scheme is proposed in this paper. Based on coriolis theorem, the fully nonlinear IGC model without the assumption that the missile flies heading to the target at initial time is established in the three-dimensional space. For this strict-feedback form of multi-variable system, dynamic surface control algorithm is implemented combining with extended observer (ESO) to complete the preliminary design. Then, in order to deal with the problems of the input constraints, a hyperbolic tangent function is introduced to approximate the saturation function and auxiliary system including a Nussbaum function established to compensate for the approximation error. The stability of the closed-loop system is proven based on Lyapunov theory. Numerical simulations results show that the proposed integrated guidance and control algorithm can ensure the accuracy of target interception with initial alignment angle deviation and the input saturation is suppressed with smooth deflection curves. PMID:27167987

  18. Effect of laser suture lysis on filtration openings: a prospective three-dimensional anterior segment optical coherence tomography study

    PubMed Central

    Cho, H-k; Kojima, S; Inoue, T; Fukushima, A; Kee, C; Tanihara, H

    2015-01-01

    Purpose To investigate the effects of laser suture lysis (LSL) on filtration openings after trabeculectomy. Methods Prospective study analyzing the changes in the location and width of filtration openings, fluid cavity height, total bleb height, bleb wall thickness, and bleb wall intensity before and after LSL using three-dimensional anterior segment optical coherence tomography (3D AS-OCT). Results Fourteen patients had clear scleral flap image analysis. As five patients underwent LSL twice and two patients underwent LSL thrice, 23 comparison studies were possible. After LSL the intraocular pressure (IOP) decreased (P=0.0015) from 20.5±5.3 to 14.9±6.4 mm Hg, and the fluid cavity height increased significantly from 0.2±0.2 mm to 0.3±0.1 mm (P=0.0094). Other bleb parameters were not significantly different when comparing before and after LSL. When the IOP reduction ratio was >25% following LSL, the width of the filtration openings on the LSL side, the total bleb height, and the fluid cavity height increased (P=0.0273, 0.0342, and 0.0024, respectively). In multiple regression analysis the changes in fluid cavity height, the wall thickness, the wall intensity, and the width of the filtration opening were positively associated with the IOP reduction rate (P=0.0428, 0.0226, 0.0420, and 0.0356, respectively). Conclusions 3D AS-OCT allowed a detailed examination of the internal morphology of filtration blebs and openings before and after LSL. The changes in the internal morphology were closely associated with the success of LSL to decrease IOP. PMID:26206528

  19. Tomographic x-ray guided three-dimensional diffuse optical imaging of osteoarthritis in the finger joints: a clinical study

    NASA Astrophysics Data System (ADS)

    Yuan, Zhen; Jiang, Huizhu; Zhang, Qizhi; Sobel, Eric S.; Jiang, Huabei

    2009-02-01

    To investigate the typical optical findings that can be used to characterize osteoarthritis, the distal interphalangeal finger joints from 40 subjects including 22 patients and 18 healthy controllers were examined clinically and scanned by a novel hybrid imaging system. The hybrid imaging platform integrated a C-arm based x-ray tomosynthetic system with a multi-channel optic-fiber based diffuse optical imaging system. Optical images were recovered qualitatively and quantitatively based on a regularization-based reconstruction algorithm that can incorporate the fine structural maps obtained from x-ray as a priori spatial information into diffuse optical tomography reconstruction procedures. Our findings suggest statistically significant differences between healthy and osteoarthritis finger joints. X-ray guided diffuse optical imaging may not only detect radiologic features supporting the development of an inflammatory disorder but may also help discriminate specific optical features that differ between osteoarthritic and healthy joints. These quantitative optical features are also potentially important for a better understanding of inflammatory arthritis in humans.

  20. Development of three-dimensional printing system for magnetic elastomer with control of magnetic anisotropy in the structure

    NASA Astrophysics Data System (ADS)

    Tsumori, Fujio; Kawanishi, Hidenori; Kudo, Kentaro; Osada, Toshiko; Miura, Hideshi

    2016-06-01

    In this paper, we report on a new system of three-dimensional (3D) printing for a magnetic elastomer that contains magnetic particles. Not only can we fabricate a three-dimensional structure, but we can also control the magnetically anisotropic property of each position in the structure using the present technique. Our new system employed photocurable poly(dimethylsiloxane) (PDMS) as the base material so that a method similar to a conventional 3D printing process with photolithography can be used. A magnetic powder was mixed with photocurable PDMS, and particle chain clusters were obtained by applying a magnetic field during the curing process. These chain clusters provide an anisotropic property in each part of the printed structure. We show some results of preliminary experiments and 3D printed samples in this paper. If the fabricated structure was placed under an applied magnetic field, each chain cluster will cause the rotational moment to be along the magnetic flux line, which can deform a soft matrix body. This deformation can be used as a magnetic actuator for the structure. Variable deformable structures could be developed using the present method.

  1. Preliminary investigations on the determination of three-dimensional dose distributions using scintillator blocks and optical tomography

    SciTech Connect

    Kroll, Florian; Karsch, Leonhard; Pawelke, Jörg

    2013-08-15

    Purpose: Clinical QA in teletherapy as well as the characterization of experimental radiation sources for future medical applications requires effective methods for measuring three-dimensional (3D) dose distributions generated in a water-equivalent medium. Current dosimeters based on ionization chambers, diodes, thermoluminescence detectors, radiochromic films, or polymer gels exhibit various drawbacks: High quality 3D dose determination is either very sophisticated and expensive or requires high amounts of effort and time for the preparation or read out. New detectors based on scintillator blocks in combination with optical tomography are studied, since they have the potential to facilitate the desired cost-effective, transportable, and long-term stable dosimetry system that is able to determine 3D dose distributions with high spatial resolution in a short time.Methods: A portable detector prototype was set up based on a plastic scintillator block and four digital cameras. During irradiation the scintillator emits light, which is detected by the fixed cameras. The light distribution is then reconstructed by optical tomography, using maximum-likelihood expectation maximization. The result of the reconstruction approximates the 3D dose distribution. First performance tests of the prototype using laser light were carried out. Irradiation experiments were performed with ionizing radiation, i.e., bremsstrahlung (6 to 21 MV), electrons (6 to 21 MeV), and protons (68 MeV), provided by clinical and research accelerators.Results: Laser experiments show that the current imaging properties differ from the design specifications: The imaging scale of the optical systems is position dependent, ranging from 0.185 mm/pixel to 0.225 mm/pixel. Nevertheless, the developed dosimetry method is proven to be functional for electron and proton beams. Induced radiation doses of 50 mGy or more made 3D dose reconstructions possible. Taking the imaging properties into account, determined

  2. Three-dimensional visualization and control of electronic warfare (EW) payloads

    NASA Astrophysics Data System (ADS)

    Kirsch, Patricia; Tremper, David; Cortesi, Roger

    2008-04-01

    The proliferation of unmanned vehicles carrying tactical payloads in the battle-space has accelerated the need for user-friendly visualization with graphical interfaces to provide remote command and control. Often these platforms and payloads receive their control functions from command centers located half a world away via satellite communications. Operators require situational awareness tools capable of graphically presenting the remote battlefield asset positions and collected sensor data. Often these systems use 2D software mapping tools in conjunction with video for real time situational awareness. The Special Projects Group (SPG) in the Tactical Electronic Warfare Division of the U.S. Naval Research Laboratory has been developing an operator control interface called the Jammer Control Station (JCS) to provide 3D battle-space visualization with built-in, remote EW payload command and control (C2) capabilities. The JCS interface presents the operator with graphic depictions of both the platforms' states and the RF environment. Text based messaging between the JCS and the EW payload reduces the impact of the system on the available bandwidth. This paper will discuss the use of the SIMDIS 3-D visualization tool as a real-time command and control interface for electronic warfare (EW) payloads.

  3. A Three-Dimensional Object Orientation Detector Assisting People with Developmental Disabilities to Control Their Environmental Stimulation through Simple Occupational Activities with a Nintendo Wii Remote Controller

    ERIC Educational Resources Information Center

    Shih, Ching-Hsiang; Chang, Man-Ling; Mohua, Zhang

    2012-01-01

    This study evaluated whether two people with developmental disabilities would be able to actively perform simple occupational activities to control their preferred environmental stimulation using a Nintendo Wii Remote Controller with a newly developed three-dimensional object orientation detection program (TDOODP, i.e. a new software program,…

  4. Feedback Control of the Wake of a Three-Dimensional Blunt Bluff Body

    NASA Astrophysics Data System (ADS)

    Flinois, Thibault; Morgans, Aimee

    2013-11-01

    When cars or trucks drive on motorways, more than two thirds of their fuel consumption is due to aerodynamic drag, a significant part of which is caused by the large scale separation that takes place near their trailing edge. We tackle this problem using Large Eddy Simulations and use feedback control of synthetic jets to reduce the losses associated with large-scale structures in the wake. The geometry is a long surface mounted block, whose leading edge is not modelled for computational efficiency and the structure of the unforced flow field around this body is similar to the flow over a surface mounted block or hump. Considering this flow field as a control system, the base pressure force was used as the system output and the input is a slot jet actuator located near the trailing edge. Using open-loop forcing, a form drag reduction of about 7.5% was obtained. Open-loop system identification also allowed a transfer function that models the system's response to actuation to be found. Finally, a set of feedback controllers were applied to the plant and their performance was analysed. These controllers successfully reduce the fluctuations in the near wake, with only a small control effort. However, more significant mean drag reductions are expected at higher Reynolds numbers. PhD Student, Imperial College London.

  5. Vital effects in coral skeletal composition display strict three-dimensional control

    USGS Publications Warehouse

    Meibom, A.; Yurimoto, H.; Cuif, J.-P.; Domart-Coulon, I.; Houlbreque, F.; Constantz, B.; Dauphin, Y.; Tambutte, E.; Tambutte, S.; Allemand, D.; Wooden, J.; Dunbar, R.

    2006-01-01

    Biological control over coral skeletal composition is poorly understood but critically important to paleoenvironmental reconstructions. We present microanalytical measurements of trace-element abundances as well as oxygen and carbon isotopic compositions of individual skeletal components in the zooxanthellate coral Colpophyllia sp. Our data show that centers of calcification (COC) have higher trace element concentrations and distinctly lighter isotopic compositions than the fibrous components of the skeleton. These observations necessitate that COC and the fibrous skeleton are precipitated by different mechanisms, which are controlled by specialized domains of the calicoblastic cell-layer. Biological processes control the composition of the skeleton even at the ultra-structure level. Copyright 2006 by the American Geophysical Union.

  6. Regional groundwater flow in mountainous terrain: Three-dimensional simulations of topographic and hydrogeologic controls

    USGS Publications Warehouse

    Gleeson, T.; Manning, A.H.

    2008-01-01

    This study uses numerical simulations to define the salient controls on regional groundwater flow in 3-D mountainous terrain by systematically varying topographic and hydrogeologic variables. Topography for idealized multiple-basin mountainous terrain is derived from geomatic data and literature values. Water table elevation, controlled by the ratio of recharge to hydraulic conductivity, largely controls the distribution of recharged water into local, regional, and perpendicular flow systems, perpendicular flow being perpendicular to the regional topographic gradient. Both the relative (%) and absolute (m 3/d) values of regional flow and perpendicular flow are examined. The relationship between regional flow and water table elevation is highly nonlinear. With lower water table elevations, relative and absolute regional flow dramatically increase and decrease, respectively, as the water table is lowered further. However, for higher water table elevations above the top of the headwater stream, changes in water table elevation have little effect on regional flow. Local flow predominates in high water table configurations, with regional and perpendicular flow <15% and <10%, respectively, of total recharge in the models tested. Both the relative and the maximum absolute regional flow are directly controlled by the degree of incision of the mountain drainage network; the elevation of mountain ridges is considerably less important. The percentage of the headwater stream with perennial streamflow is a potentially powerful indicator of regional flow in all water table configurations and may be a good indicator of the susceptibility of mountain groundwater systems to increased aridity. Copyright 2008 by the American Geophysical Union.

  7. Three-dimensional flow dynamics and control of nominally two-dimensional shedding bodies

    NASA Astrophysics Data System (ADS)

    El-Gammal, Mohamed M.

    The present doctoral research is based on an experimental investigation that provides fundamental understanding for the flow dynamics in asymmetric wake of a blunt and divergent trailing edge airfoil (DTE), at high Reynolds numbers. This fundamental insight is then exploited to develop optimized flow control strategies. Furthermore, the applicability of such efficient flow control methods to bridge deck sections exhibiting vortex induced vibration problem is investigated. The research work sheds light on the airfoil near wake flow coherent structures and their downstream evolution. Spanwise von Karman vortices as well as streamwise vortices are identified in the near wake. Their spatial arrangement is determined throughout conducting simultaneous multi-point hot-wire measurements. The sensitivity of the airfoil wake versus different levels of free stream turbulence (FST) and angles of attack is examined. The FST affects the shapes of turbulence profiles and accelerates the wake decay rate. The results suggest that the statistical spanwise distribution of the streamwise vortices is independent of FST effects and angle of attack as long as the Strouhal number remains approximately similar. Information related to the airfoil surface flow is quantified throughout surface pressure and skin friction measurements. Both measurement techniques led to accurate determination of the airfoil profile drag. Controlling the wake vortex shedding and base drag throughout flow control methods developed from information related to the airfoil natural near wake topology is investigated: vortex generators (VGs) and spanwise sinusoidal perturbation method (SSP). Both flow control methods significantly suppress vortex shedding. The SSP has the advantage of reducing the base drag. Applying a round trailing edge is also examined. The round trailing edge reduces base drag: however, it enhances vortex shedding strength. The effectiveness of SSP in controlling vortex induced vibrations (VIV

  8. Three-dimensional non-destructive optical evaluation of laser-processing performance using optical coherence tomography

    PubMed Central

    Kim, Youngseop; Choi, Eun Seo; Kwak, Wooseop; Shin, Yongjin; Jung, Woonggyu; Ahn, Yeh-Chan; Chen, Zhongping

    2014-01-01

    We demonstrate the use of optical coherence tomography (OCT) as a non-destructive diagnostic tool for evaluating laser-processing performance by imaging the features of a pit and a rim. A pit formed on a material at different laser-processing conditions is imaged using both a conventional scanning electron microscope (SEM) and OCT. Then using corresponding images, the geometrical characteristics of the pit are analyzed and compared. From the results, we could verify the feasibility and the potential of the application of OCT to the monitoring of the laser-processing performance. PMID:24932051

  9. Three-Dimensional Model for Electrospinning Processes in Controlled Gas Counterflow

    PubMed Central

    2016-01-01

    We study the effects of a controlled gas flow on the dynamics of electrified jets in the electrospinning process. The main idea is to model the air drag effects of the gas flow by using a nonlinear Langevin-like approach. The model is employed to investigate the dynamics of electrified polymer jets at different conditions of air drag force, showing that a controlled gas counterflow can lead to a decrease of the average diameter of electrospun fibers, and potentially to an improvement of the quality of electrospun products. We probe the influence of air drag effects on the bending instabilities of the jet and on its angular fluctuations during the process. The insights provided by this study might prove useful for the design of future electrospinning experiments and polymer nanofiber materials. PMID:26859532

  10. Factors controlling the fault occurrences in Tangzhuang three-dimensional exploration area in Dongpu depression

    SciTech Connect

    Jia, Z. )

    1992-01-01

    This paper reports that there are NNE and NNE-NE fault systems in the Dongpu depression. The NNE-NE fault system exists in Tangzhuang hydrocarbon exploration area. In this area, fault occurrence changes frequently, so that in 20 km extent there occur 6 fault zones whose dip directions are opposite each other. The NNE fault system is mainly controlled by tension-torsional stress, and the NNE-NE fault system by these factors: boundary condition, sedimentary facies zone and regional tensional stress. The factors controlling Tangzhuang fault zones whose dip directions are opposite each other are evolution environment of regional geology, structure background, boundary condition, lithology and rock facies variations, as well as the tilting-turning and differential uplifting of faulted blocks, etc. In other words, these opposite fault zones were caused by the above factors.

  11. Bioprinting three-dimensional cell-laden tissue constructs with controllable degradation

    PubMed Central

    Wu, Zhengjie; Su, Xin; Xu, Yuanyuan; Kong, Bin; Sun, Wei; Mi, Shengli

    2016-01-01

    Alginate hydrogel is a popular biologically inert material that is widely used in 3D bioprinting, especially in extrusion-based printing. However, the printed cells in this hydrogel could not degrade the surrounding alginate gel matrix, causing them to remain in a poorly proliferating and non-differentiating state. Here, we report a novel study of the 3D printing of human corneal epithelial cells (HCECs)/collagen/gelatin/alginate hydrogel incubated with a medium containing sodium citrate to obtain degradation-controllable cell-laden tissue constructs. The 3D-printed hydrogel network with interconnected channels and a macroporous structure was stable and achieved high cell viability (over 90%). By altering the mole ratio of sodium citrate/sodium alginate, the degradation time of the bioprinting constructs can be controlled. Cell proliferation and specific marker protein expression results also revealed that with the help of sodium citrate degradation, the printed HCECs showed a higher proliferation rate and greater cytokeratin 3(CK3) expression, indicating that this newly developed method may help to improve the alginate bioink system for the application of 3D bioprinting in tissue engineering. PMID:27091175

  12. Three-Dimensional Branched TiO2 Architectures in Controllable Bloom for Advanced Lithium-Ion Batteries.

    PubMed

    Wang, Shaofu; Qu, Dandan; Jiang, Yun; Xiong, Wan-Sheng; Sang, Hong-Qian; He, Rong-Xiang; Tai, Qidong; Chen, Bolei; Liu, Yumin; Zhao, Xing-Zhong

    2016-08-10

    Three-dimensional branched TiO2 architectures (3D BTA) with controllable morphologies were synthesized via a facile template-free one-pot solvothermal route. The volume ratio of deionized water (DI water) and diethylene glycol in solvothermal process is key to the formation of 3D BTA assembled by nanowire-coated TiO2 dendrites, which combines the advantages of 3D hierarchical structure and 1D nanoscale building blocks. Benefiting from such unique structural features, the BTA in full bloom achieved significantly increased specific surface areas and shortened Li(+) ion/electrons diffusion pathway. The lithium-ion batteries based on BTA in full bloom exhibited remarkably enhanced reversible specific capacity and rate performance, attributing to the high contact area with the electrolyte and the short solid state diffusion pathway for Li(+) ion/electrons promoting lithium insertion and extraction. PMID:27420343

  13. Computational algorithms for increased control of depth-viewing volume for stereo three-dimensional graphic displays

    NASA Technical Reports Server (NTRS)

    Williams, Steven P.; Parrish, Russell V.

    1992-01-01

    Three-dimensional pictorial displays incorporating depth cues by means of stereopsis offer a potential means of presenting information in a natural way to enhance situational awareness and improve operator performance. Conventional computational techniques rely on asymptotic projection transformations and symmetric clipping to produce the stereo display. Implementation of two new computational techniques, as asymmetric clipping algorithm and piecewise linear projection transformation, provides the display designer with more control and better utilization of the effective depth-viewing volume to allow full exploitation of stereopsis cuing. Asymmetric clipping increases the perceived field of view (FOV) for the stereopsis region. The total horizontal FOV provided by the asymmetric clipping algorithm is greater throughout the scene viewing envelope than that of the symmetric algorithm. The new piecewise linear projection transformation allows the designer to creatively partition the depth-viewing volume, with freedom to place depth cuing at the various scene distances at which emphasis is desired.

  14. A diffuser-based three-dimensional measurement of polarization-dependent scattering characteristics of optical films for 3D-display applications.

    PubMed

    Kim, Dae-Yeon; Seo, Jong-Wook

    2015-01-26

    We propose an accurate and easy-to-use three-dimensional measurement method using a diffuser plate to analyze the scattering characteristics of optical films. The far-field radiation pattern of light scattered by the optical film is obtained from the illuminance pattern created on the diffuser plate by the light. A mathematical model and calibration methods were described, and the results were compared with those obtained by a direct measurement using a luminance meter. The new method gave very precise three-dimensional polarization-dependent scattering characteristics of scattering polarizer films, and it can play an effective role in developing high performance polarization-selective screens for 3D display applications. PMID:25835866

  15. Vector theory of laser radiation scattering in an integrated optical waveguide with three-dimensional irregularities in the presence of noise

    SciTech Connect

    Egorov, Alexander A

    2004-08-31

    The vector theory of laser radiation scattering in an integrated optical waveguide with three-dimensional irregularities in the presence of noise is developed. The solution of the electrodynamic problem of laser radiation scattering in an irregular waveguide is obtained by the mode coupling technique using the perturbation theory. An approximate solution of the inhomogeneous three-dimensional wave equation is obtained by the method of Green's functions. The analytic formulas are derived for the radiation fields of propagating and evanescent modes. A physical interpretation is given for the obtained results. The role of noise as an independent depolarising factor (in addition to the classical one) during scattering of light is pointed out. (integrated optical waveguides and devices)

  16. Dynamic Three-Dimensional Ultrasound to Evaluate Scapular Movement Among Manual Wheelchair Users and Healthy Controls

    PubMed Central

    Lin, Yen-Sheng; Koontz, Alicia M.; Boninger, Michael L.

    2015-01-01

    Background: A large percentage of individuals with spinal cord injury (SCI) report shoulder pain that can limit independence and quality of life. The pain is likely related to the demands placed on the shoulder by transfers and propulsion. Shoulder pathology has been linked to altered scapular mechanics; however, current methods to evaluate scapular movement are invasive, require ionizing radiation, are subject to skin-based motion artifacts, or require static postures. Objective: To investigate the feasibility of applying 3-dimensional ultrasound methods, previously used to look at scapular position in static postures, to evaluate dynamic scapular movement. Method: This study evaluated the feasibility of the novel application of a method combining 2-dimensional ultrasound and a motion capture system to determine 3-dimensional scapular position during dynamic arm elevation in the scapular plane with and without loading. Results: Incremental increases in scapular rotations were noted for extracted angles of 30°, 45°, 60°, and 75° of humeral elevation. Group differences were evaluated between a group of 16 manual wheelchair users (MWUs) and a group of age- and gender-matched able-bodied controls. MWUs had greater scapular external rotation and baseline pathology on clinical exam. MWUs also had greater anterior tilting, with this difference further accentuated during loading. The relationship between demographics and scapular positioning was also investigated, revealing that increased age, pathology on clinical exam, years since injury, and body mass index were correlated with scapular rotations associated with impingement (internal rotation, downward rotation, and anterior tilting). Conclusion: Individuals with SCI, as well as other populations who are susceptible to shoulder pathology, may benefit from the application of this imaging modality to quantitatively evaluate scapular positioning and effectively target therapeutic interventions. PMID:26689695

  17. Modeling and Control of Three-Dimensional Grasping by a Pair of Robot Fingers

    NASA Astrophysics Data System (ADS)

    Arimoto, Suguru; Yoshida, Morio

    This paper extends a stability theory of 2-D object grasp to cope with 3-dimensional(3-D) object grasp by a pair of multi-joint robot fingers with hemi-spheric ends. It shows that secure grasp of a 3-D object with parallel surfaces in a dynamic sense can be realized in a blind manner like human grasp an object by a pair of thumb and index finger while their eyes closed. Rolling contacts are modeled as Pfaffian constraints that can not be integrated into holonomic constraints but exert tangential constraint forces on the object surfaces. A noteworthy difference of modeling of 3-D object grasping from the 2-D case is that the instantaneous axis of rotation of the object dynamics of the overall fingers-object system are subject to non-holonomic constraints regarding a 3-D orthogonal matrix consisting of three mutually orthogonal unit-vectors fixed at the object. Lagrange's equation of motion of the overall system can be derived from the variational principle without violating the causality that governs the nonholonomic constraints. Then, a simple control signal constructed on the basis of fingers-thumb opposable forces together with an object-mass estimator is shown to accomplish stable grasp in a dynamic sense without using object information or external sensing. The closed-loop dynamics can be regarded as Lagrange's equation of motion with an artificial potential function that attains its minimum at some equilibrium state of force/torque balance. A mathematical proof of stability and asymptotic stability on a constraint manifold of the closed-loop dynamics under the nonholonomic constraints is presented.

  18. Three-Dimensional Level Set Modelling of Capillary-Controlled Displacements in Digital Porous Media

    NASA Astrophysics Data System (ADS)

    Helland, J.; Jettestuen, E.; Hatzignatiou, D. G.; Silin, D.

    2011-12-01

    In geological CO2 storage capillary entry pressures for CO2 invasion into low-permeability formation layers or cap rock are required for a reliable prediction of the displacement front in the storage site. High capillary entry pressures can hinder upward migration of CO2 causing it to either move laterally or get trapped. We present a 3D level set model for simulating capillary-controlled displacements in 3D rock images. Capillary pressure and interfacial area - saturation curves, as well as mean and principal interface curvatures are computed from the proposed model. The level set model is compared with a 2D semi-analytical model for calculating capillary pressure curves and arc menisci configurations in straight tubes with pore cross-sections obtained from 2D rock images. The critical displacement events and capillary entry pressures simulated with both models are in agreement. The level set simulations show that the computed mean curvature is approximately constant everywhere on the interfaces at steady state, whereas the two principal interface curvatures can vary significantly in pore space constrictions. It is also shown that the semi-analytical model provides a sufficient approximation to the initial fluid configuration required by the level set model. Level set simulations are performed in 3D images of random sphere packs (see Figure) and sandstone rocks, and the computed capillary pressure and interfacial area curves exhibit similar trends as measured data. Impacts of grid refinement on the simulated results are explored. It is demonstrated that the model accounts for several well documented critical pore level phenomena in 3D porous media, such as co-operative pore filling and Haines jumps. Furthermore, the non-wetting fluid is observed to snap off water by coalescence of opposite interfaces. These simulations also show that the two principal curvatures can vary significantly, which indicates that the shape of the interfaces is far from spherical in many

  19. Three-dimensional localisation of DNA in the nucleolus of Spirogyra by correlated optical tomography and serial ultra-thin sectioning.

    PubMed

    Jordan, E G; Rawlins, D J

    1990-03-01

    Spirogyra nucleoli were shown by three-dimensional optical microscopy of DAPI fluorescence to contain DNA with a pattern and distribution matching those of the fibrillar centres. This was confirmed using different species with nucleoli showing different sizes of fibrillar centre. Much lower levels of fluorescence were seen corresponding to the dense fibrillar component. Nearly all the DAPI fluorescence arises from the fibrillar centres or from regions very close to their surface, indicating that this is the site of nucleolar transcription.

  20. A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise.

    PubMed

    Arthurs, Christopher J; Lau, Kevin D; Asrress, Kaleab N; Redwood, Simon R; Figueroa, C Alberto

    2016-05-01

    This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. PMID:26945076

  1. A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise

    PubMed Central

    Lau, Kevin D.; Asrress, Kaleab N.; Redwood, Simon R.; Figueroa, C. Alberto

    2016-01-01

    This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. PMID:26945076

  2. Three-dimensional silicon micromachining

    NASA Astrophysics Data System (ADS)

    Azimi, S.; Song, J.; Dang, Z. Y.; Liang, H. D.; Breese, M. B. H.

    2012-11-01

    A process for fabricating arbitrary-shaped, two- and three-dimensional silicon and porous silicon components has been developed, based on high-energy ion irradiation, such as 250 keV to 1 MeV protons and helium. Irradiation alters the hole current flow during subsequent electrochemical anodization, allowing the anodization rate to be slowed or stopped for low/high fluences. For moderate fluences the anodization rate is selectively stopped only at depths corresponding to the high defect density at the end of ion range, allowing true three-dimensional silicon machining. The use of this process in fields including optics, photonics, holography and nanoscale depth machining is reviewed.

  3. Patterned and functionalized nanofiber scaffolds in three-dimensional hydrogel constructs enhance neurite outgrowth and directional control

    NASA Astrophysics Data System (ADS)

    McMurtrey, Richard J.

    2014-12-01

    Objective. Neural tissue engineering holds incredible potential to restore functional capabilities to damaged neural tissue. It was hypothesized that patterned and functionalized nanofiber scaffolds could control neurite direction and enhance neurite outgrowth. Approach. A method of creating aligned electrospun nanofibers was implemented and fiber characteristics were analyzed using environmental scanning electron microscopy. Nanofibers were composed of polycaprolactone (PCL) polymer, PCL mixed with gelatin, or PCL with a laminin coating. Three-dimensional hydrogels were then integrated with embedded aligned nanofibers to support neuronal cell cultures. Microscopic images were captured at high-resolution in single and multi-focal planes with eGFP-expressing neuronal SH-SY5Y cells in a fluorescent channel and nanofiber scaffolding in another channel. Neuronal morphology and neurite tracking of nanofibers were then analyzed in detail. Main results. Aligned nanofibers were shown to enable significant control over the direction of neurite outgrowth in both two-dimensional (2D) and three-dimensional (3D) neuronal cultures. Laminin-functionalized nanofibers in 3D hyaluronic acid (HA) hydrogels enabled significant alignment of neurites with nanofibers, enabled significant neurite tracking of nanofibers, and significantly increased the distance over which neurites could extend. Specifically, the average length of neurites per cell in 3D HA constructs with laminin-functionalized nanofibers increased by 66% compared to the same laminin fibers on 2D laminin surfaces, increased by 59% compared to 2D laminin-coated surface without fibers, and increased by 1052% compared to HA constructs without fibers. Laminin functionalization of fibers also doubled average neurite length over plain PCL fibers in the same 3D HA constructs. In addition, neurites also demonstrated tracking directly along the fibers, with 66% of neurite lengths directly tracking laminin-coated fibers in 3D HA

  4. Ultrahigh-Speed Optical Coherence Tomography for Three-Dimensional and En Face Imaging of the Retina and Optic Nerve Head

    PubMed Central

    Srinivasan, Vivek J.; Adler, Desmond C.; Chen, Yueli; Gorczynska, Iwona; Huber, Robert; Duker, Jay S.; Schuman, Joel S.; Fujimoto, James G.

    2009-01-01

    Purpose To demonstrate ultrahigh-speed optical coherence tomography (OCT) imaging of the retina and optic nerve head at 249,000 axial scans per second and a wavelength of 1060 nm. To investigate methods for visualization of the retina, choroid, and optic nerve using high-density sampling enabled by improved imaging speed. Methods A swept-source OCT retinal imaging system operating at a speed of 249,000 axial scans per second was developed. Imaging of the retina, choroid, and optic nerve were performed. Display methods such as speckle reduction, slicing along arbitrary planes, en face visualization of reflectance from specific retinal layers, and image compounding were investigated. Results High-definition and three-dimensional (3D) imaging of the normal retina and optic nerve head were performed. Increased light penetration at 1060 nm enabled improved visualization of the choroid, lamina cribrosa, and sclera. OCT fundus images and 3D visualizations were generated with higher pixel density and less motion artifacts than standard spectral/Fourier domain OCT. En face images enabled visualization of the porous structure of the lamina cribrosa, nerve fiber layer, choroid, photoreceptors, RPE, and capillaries of the inner retina. Conclusions Ultrahigh-speed OCT imaging of the retina and optic nerve head at 249,000 axial scans per second is possible. The improvement of ∼5 to 10× in imaging speed over commercial spectral/Fourier domain OCT technology enables higher density raster scan protocols and improved performance of en face visualization methods. The combination of the longer wavelength and ultrahigh imaging speed enables excellent visualization of the choroid, sclera, and lamina cribrosa. PMID:18658089

  5. Theoretical assessment of optical resolution enhancement and background fluorescence reduction by three-dimensional nonlinear structured illumination microscopy using stimulated emission depletion

    NASA Astrophysics Data System (ADS)

    Dake, Fumihiro

    2016-08-01

    Three-dimensional structured illumination microscopy (SIM) enlarges frequency cutoff laterally and axially by a factor of two, compared with conventional microscopy. However, its optical resolution is still fundamentally limited. It is necessary to introduce nonlinearity to enlarge frequency cutoff further. We propose three-dimensional nonlinear structured illumination microscopy based on stimulated emission depletion (STED) effect, which has a structured excitation pattern and a structured STED pattern, and both three-dimensional illumination patterns have the same lateral pitch and orientation. Theoretical analysis showed that nonlinearity induced by STED effect, which causes harmonics and contributes to enlarging frequency cutoff, depends on the phase difference between two structured illuminations and that the phase difference of π is the most efficient to increase nonlinearity. We also found that undesirable background fluorescence, which degenerates the contrast of structured pattern and limits the ability of SIM, can be reduced by our method. These results revealed that optical resolution improvement and background fluorescence reduction would be compatible. The feasibility study showed that our method will be realized with commercially available laser, having 3.5 times larger frequency cutoff compared with conventional microscopy.

  6. Direct-Write, Self-Aligned Electrospinning on Paper for Controllable Fabrication of Three-Dimensional Structures.

    PubMed

    Luo, Guoxi; Teh, Kwok Siong; Liu, Yumeng; Zang, Xining; Wen, Zhiyu; Lin, Liwei

    2015-12-23

    Electrospinning, a process that converts a solution or melt droplet into an ejected jet under a high electric field, is a well-established technique to produce one-dimensional (1D) fibers or two-dimensional (2D) randomly arranged fibrous meshes. Nevertheless, the direct electrospinning of fibers into controllable three-dimensional (3D) architectures is still a nascent technology. Here, we apply near-field electrospinning (NFES) to directly write arbitrarily shaped 3D structures through consistent and spatially controlled fiber-by-fiber stacking of polyvinylidene fluoride (PVDF) fibers. An element central to the success of this 3D electrospinning is the use of a printing paper placed on the grounded conductive plate and acting as a fiber collector. Once deposited on the paper, residual solvents from near-field electrospun fibers can infiltrate the paper substrate, enhancing the charge transfer between the deposited fibers and the ground plate via the fibrous network within the paper. Such charge transfer grounds the deposited fibers and turns them into locally fabricated electrical poles, which attract subsequent in-flight fibers to deposit in a self-aligned manner on top of each other. This process enables the design and controlled fabrication of electrospun 3D structures such as grids, walls, hollow cylinders, and other 3D logos. As such, this technique has the potential to advance the existing electrospinning technologies in constructing 3D structures for biomedical, microelectronics, and MEMS/NMES applications.

  7. Three-dimensional object-oriented modeling of the stomach for the purpose of microprocessor-controlled functional stimulation.

    PubMed

    Rashev, Peter Z; Bowes, Kenneth L; Mintchev, Martin P

    2002-12-01

    Three-dimensional (3-D) object-oriented models are needed for optimizing gastric electrical stimulation by performing virtual computer experiments. The aim of the study was to create a 3-D object-oriented electromechanical model of the stomach in vivo for the purpose of microprocessor controlled functional stimulation. The stomach was modeled using coaxial truncated conoids as objects. The strength of an external stimulating electric field generated by circumferentially implanted wire electrodes is related to artificial neurogenic and myogenic control of smooth muscle depolarization and contraction. Variation of the field strength modulates the frequency and concentration of acetylcholine release, as well as the transmembrane voltage of the muscle cells. Mechanical response of the stimulated tissue was quantified by two parametric functions of the electric field strength representing the relative contractile force and geometrical displacement of the gastric surface. Data from previously conducted canine experiments were used to test the validity of the model. The model was applied to simulate contractions with different positions, orientation and number of the circumferentially implanted stimulating electrodes. The model combined most of the existing theoretical and experimental findings concerning functional gastric stimulation and can be utilized as a flexible tool for virtual medical tests involving external high-frequency (50 Hz) neural stimulation.

  8. Quadcopter control in three-dimensional space using a noninvasive motor imagery-based brain-computer interface

    NASA Astrophysics Data System (ADS)

    LaFleur, Karl; Cassady, Kaitlin; Doud, Alexander; Shades, Kaleb; Rogin, Eitan; He, Bin

    2013-08-01

    Objective. At the balanced intersection of human and machine adaptation is found the optimally functioning brain-computer interface (BCI). In this study, we report a novel experiment of BCI controlling a robotic quadcopter in three-dimensional (3D) physical space using noninvasive scalp electroencephalogram (EEG) in human subjects. We then quantify the performance of this system using metrics suitable for asynchronous BCI. Lastly, we examine the impact that the operation of a real world device has on subjects' control in comparison to a 2D virtual cursor task. Approach. Five human subjects were trained to modulate their sensorimotor rhythms to control an AR Drone navigating a 3D physical space. Visual feedback was provided via a forward facing camera on the hull of the drone. Main results. Individual subjects were able to accurately acquire up to 90.5% of all valid targets presented while travelling at an average straight-line speed of 0.69 m s-1. Significance. Freely exploring and interacting with the world around us is a crucial element of autonomy that is lost in the context of neurodegenerative disease. Brain-computer interfaces are systems that aim to restore or enhance a user's ability to interact with the environment via a computer and through the use of only thought. We demonstrate for the first time the ability to control a flying robot in 3D physical space using noninvasive scalp recorded EEG in humans. Our work indicates the potential of noninvasive EEG-based BCI systems for accomplish complex control in 3D physical space. The present study may serve as a framework for the investigation of multidimensional noninvasive BCI control in a physical environment using telepresence robotics.

  9. Resolving three-dimensional shape of sub-50 nm wide lines with nanometer-scale sensitivity using conventional optical microscopes

    SciTech Connect

    Attota, Ravikiran Dixson, Ronald G.

    2014-07-28

    We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 4-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30 nm–40 nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22 nm (k = 2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast, and ideally suited for high volume nanomanufacturing process monitoring.

  10. Optic-electronic system for measuring the three-dimensional angular deformation of pipe sections at large constructions

    NASA Astrophysics Data System (ADS)

    Konyakhin, Igor; Hoang, Van Phong; Artemenko, Yury; Li, Renpu; Smekhov, Andrey

    2015-05-01

    The improved autocollimation system for measuring three-dimension angular deformations of pipe sections at large constructions as support tube of radio telescope mirror is analyzed. New type of the reflector for autocollimators is researched. The reflector is the trihedral mirror composition of three reflecting sides. It advantage is the measurement pitch, yaw and torsion as three angular rotation of controlled object. The second advantage of reflector is the measurements on the large work distances. Causes are the small value of the conversion coefficient and two orthogonal reference axes of trihedral reflector. The technical characteristics of the experimental setups of new reflector are presented. The features of trihedral reflector as the reflectors for optic-electronic autocollimators are discussed.

  11. Design of anti-ring back reflectors for thin-film solar cells based on three-dimensional optical and electrical modeling

    SciTech Connect

    Hsiao, Hui-Hsin; Wu, Yuh-Renn; Chang, Hung-Chun

    2014-08-11

    The optical and electrical properties of a photonic-plasmonic nanostructure on the back contact of thin-film solar cells were investigated numerically through the three-dimensional (3D) finite-difference time-domain method and the 3D Poisson and drift-diffusion solver. The focusing effect and the Fabry-Perot resonances are identified as the main mechanisms for the enhancement of the optical generation rate as well as the short circuit current density. However, the surface topography of certain nanopattern structures is found to reduce the internal electrostatic field of the device, thus limiting charge collection. The optimized conditions for both optics and electronics have been analyzed in this paper.

  12. Design and implementation of three-dimensional ring-scanning equipment for optimized measurements of near-infrared diffuse optical breast imaging

    NASA Astrophysics Data System (ADS)

    Yu, Jhao-Ming; Pan, Min-Cheng; Hsu, Ya-Fen; Chen, Liang-Yu; Pan, Min-Chun

    2015-07-01

    We propose and implement three-dimensional (3-D) ring-scanning equipment for near-infrared (NIR) diffuse optical imaging to screen breast tumors under prostrating examination. This equipment has the function of the radial, circular, and vertical motion without compression of breast tissue, thereby achieving 3-D scanning; furthermore, a flexible combination of illumination and detection can be configured for the required resolution. Especially, a rotation-sliding-and-moving mechanism was designed for the guidance of source- and detection-channel motion. Prior to machining and construction of the system, a synthesized image reconstruction was simulated to show the feasibility of this 3-D NIR ring-scanning equipment; finally, this equipment is verified by performing phantom experiments. Rather than the fixed configuration, this addressed screening/diagnosing equipment has the flexibilities of optical-channel expansion for spatial resolution and the dimensional freedom for scanning in reconstructing optical-property images.

  13. Solvothermal synthesis and high optical performance of three-dimensional sea-urchin-like TiO{sub 2}

    SciTech Connect

    Zhou, Yi Wang, Yutang; Li, Mengyao; Li, Xuzhi; Yi, Qin; Deng, Pan; Wu, Hongyan

    2015-06-15

    Graphical abstract: I–V characteristics of different TiO{sub 2} microspheres based DSSCs (a) 3D sphere-like, (b) 3D flower-like, (c) 3D sea-urchin-like. - Highlights: • 3D sea-urchin-like TiO{sub 2} was synthesized by solvothermal method. • The effects of preparation parameters on the microstructure of the microspheres were investigated. • The photoelectric properties of 3D sea-urchin-like TiO{sub 2} were studied upon DSSCs. • The PCE of the 3D sea-urchin-like TiO{sub 2} was higher than that of other morphologies. - Abstract: Three-dimensional (3D) sea-urchin-like TiO{sub 2} microspheres were successfully synthesised by solvothermal method. The effects of preparation parameters including reaction temperature, concentration and mass fraction of precursor, and solvent volume on the microstructure of the microspheres were investigated. Results of scanning electron microscopy showed that the preparation parameters played a critical role in the morphology of 3D sea-urchin-like TiO{sub 2}. In addition, when the sea-urchin-like TiO{sub 2} nanostructures were used as the dye-sensitized solar cells (DSSCs) anode, the power-conversion efficiency was higher than that of other morphologies, which was due to the special 3D hierarchical nanostructure, large specific surface area, and enhanced absorption of UV–vis of the TiO{sub 2} nanostructures.

  14. Development of an optical three-dimensional laser tracker using dual modulated laser diodes and a signal detector

    SciTech Connect

    Lee, Hau-Wei; Chen, Chieh-Li; Liu, Chien-Hung

    2011-03-15

    Laser trackers are widely used in industry for tasks such as the assembly of airplanes and automobiles, contour measurement, and robot calibration. However, laser trackers are expensive, and the corresponding solution procedure is very complex. The influence of measurement uncertainties is also significant. This study proposes a three-dimensional space position measurement system which consists of two tracking modules, a zero tracking angle return subsystem, and a target quadrant photodiode (QPD). The target QPD is placed on the object being tracked. The origin locking method is used to keep the rays on the origin of the target QPD. The position of the target QPD is determined using triangulation since the two laser rays are projected onto one QPD. Modulation and demodulation are utilized to separate the coupled positional values. The experiment results show that measurement errors in the X, Y, and Z directions are less than {+-}0.05% when the measured object was moved by 300, 300, and 200 mm in the X, Y, and Z axes, respectively. The theoretical measurement error estimated from the measurement model is between {+-}0.02% and {+-}0.07% within the defined measurable range. The proposed system can be applied to the measurements of machine tools and robot arms.

  15. Real-time three-dimensional imaging of epidermal splitting and removal by high-definition optical coherence tomography.

    PubMed

    Boone, Marc; Draye, Jean Pierre; Verween, Gunther; Pirnay, Jean-Paul; Verbeken, Gilbert; De Vos, Daniel; Rose, Thomas; Jennes, Serge; Jemec, Gregor B E; Del Marmol, Véronique

    2014-10-01

    While real-time 3-D evaluation of human skin constructs is needed, only 2-D non-invasive imaging techniques are available. The aim of this paper is to evaluate the potential of high-definition optical coherence tomography (HD-OCT) for real-time 3-D assessment of the epidermal splitting and decellularization. Human skin samples were incubated with four different agents: Dispase II, NaCl 1 M, sodium dodecyl sulphate (SDS) and Triton X-100. Epidermal splitting, dermo-epidermal junction, acellularity and 3-D architecture of dermal matrices were evaluated by High-definition optical coherence tomography before and after incubation. Real-time 3-D HD-OCT assessment was compared with 2-D en face assessment by reflectance confocal microscopy (RCM). (Immuno) histopathology was used as control. HD-OCT imaging allowed real-time 3-D visualization of the impact of selected agents on epidermal splitting, dermo-epidermal junction, dermal architecture, vascular spaces and cellularity. RCM has a better resolution (1 μm) than HD-OCT (3 μm), permitting differentiation of different collagen fibres, but HD-OCT imaging has deeper penetration (570 μm) than RCM imaging (200 μm). Dispase II and NaCl treatments were found to be equally efficient in the removal of the epidermis from human split-thickness skin allografts. However, a different epidermal splitting level at the dermo-epidermal junction could be observed and confirmed by immunolabelling of collagen type IV and type VII. Epidermal splitting occurred at the level of the lamina densa with dispase II and above the lamina densa (in the lamina lucida) with NaCl. The 3-D architecture of dermal papillae and dermis was more affected by Dispase II on HD-OCT which corresponded with histopathologic (orcein staining) fragmentation of elastic fibres. With SDS treatment, the epidermal removal was incomplete as remnants of the epidermal basal cell layer remained attached to the basement membrane on the dermis. With Triton X-100 treatment

  16. Three-dimensional photovoltaics

    NASA Astrophysics Data System (ADS)

    Myers, Bryan; Bernardi, Marco; Grossman, Jeffrey C.

    2010-02-01

    The concept of three-dimensional (3D) photovoltaics is explored computationally using a genetic algorithm to optimize the energy production in a day for arbitrarily shaped 3D solar cells confined to a given area footprint and total volume. Our simulations demonstrate that the performance of 3D photovoltaic structures scales linearly with height, leading to volumetric energy conversion, and provides power fairly evenly throughout the day. Furthermore, we show that optimal 3D structures are not simple box-like shapes, and that design attributes such as reflectivity could be optimized using three-dimensionality.

  17. Three-dimensional photovoltaics

    NASA Astrophysics Data System (ADS)

    Myers, Bryan; Bernardi, Marco; Grossman, Jeffrey C.

    2010-03-01

    The concept of three-dimensional (3D) photovoltaics is explored computationally using a genetic algorithm to optimize the energy production in a day for arbitrarily shaped 3D solar cells confined to a given area footprint and total volume. Our simulations demonstrate that the performance of 3D photovoltaic structures scales linearly with height, leading to volumetric energy conversion, and provides power fairly evenly throughout the day. Furthermore, we show that optimal 3D shapes are not simple box-like shapes, and that design attributes such as reflectivity can be optimized in new ways using three-dimensionality.

  18. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres.

    PubMed

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-06-24

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices.

  19. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres

    NASA Astrophysics Data System (ADS)

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-06-01

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices.

  20. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres.

    PubMed

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-01-01

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices. PMID:27339700

  1. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres

    PubMed Central

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-01-01

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices. PMID:27339700

  2. Transverse writing of three-dimensional tubular optical waveguides in glass with a slit-shaped femtosecond laser beam

    PubMed Central

    Liao, Yang; Qi, Jia; Wang, Peng; Chu, Wei; Wang, Zhaohui; Qiao, Lingling; Cheng, Ya

    2016-01-01

    We report on fabrication of tubular optical waveguides buried in ZBLAN glass based on transverse femtosecond laser direct writing. Irradiation in ZBLAN with focused femtosecond laser pulses leads to decrease of refractive index in the modified region. Tubular optical waveguides of variable mode areas are fabricated by forming the four sides of the cladding with slit-shaped femtosecond laser pulses, ensuring single mode waveguiding with a mode field dimension as small as ~4 μm. PMID:27346285

  3. Transverse writing of three-dimensional tubular optical waveguides in glass with a slit-shaped femtosecond laser beam

    NASA Astrophysics Data System (ADS)

    Liao, Yang; Qi, Jia; Wang, Peng; Chu, Wei; Wang, Zhaohui; Qiao, Lingling; Cheng, Ya

    2016-06-01

    We report on fabrication of tubular optical waveguides buried in ZBLAN glass based on transverse femtosecond laser direct writing. Irradiation in ZBLAN with focused femtosecond laser pulses leads to decrease of refractive index in the modified region. Tubular optical waveguides of variable mode areas are fabricated by forming the four sides of the cladding with slit-shaped femtosecond laser pulses, ensuring single mode waveguiding with a mode field dimension as small as ~4 μm.

  4. Three-dimensional study of planar optical antennas made of split-ring architecture outperforming dipole antennas for increased field localization.

    PubMed

    Kilic, Veli Tayfun; Erturk, Vakur B; Demir, Hilmi Volkan

    2012-01-15

    Optical antennas are of fundamental importance for the strongly localizing field beyond the diffraction limit. We report that planar optical antennas made of split-ring architecture are numerically found in three-dimensional simulations to outperform dipole antennas for the enhancement of localized field intensity inside their gap regions. The computational results (finite-difference time-domain) indicate that the resulting field localization, which is of the order of many thousandfold, in the case of the split-ring resonators is at least 2 times stronger than the one in the dipole antennas resonant at the same operating wavelength, while the two antenna types feature the same gap size and tip sharpness.

  5. High-resolution three-dimensional imaging of red blood cells parasitized by Plasmodium falciparum and in situ hemozoin crystals using optical diffraction tomography

    PubMed Central

    Kim, Kyoohyun; Yoon, HyeOk; Diez-Silva, Monica; Dao, Ming; Dasari, Ramachandra R.

    2013-01-01

    Abstract. We present high-resolution optical tomographic images of human red blood cells (RBC) parasitized by malaria-inducing Plasmodium falciparum (Pf)-RBCs. Three-dimensional (3-D) refractive index (RI) tomograms are reconstructed by recourse to a diffraction algorithm from multiple two-dimensional holograms with various angles of illumination. These 3-D RI tomograms of Pf-RBCs show cellular and subcellular structures of host RBCs and invaded parasites in fine detail. Full asexual intraerythrocytic stages of parasite maturation (ring to trophozoite to schizont stages) are then systematically investigated using optical diffraction tomography algorithms. These analyses provide quantitative information on the structural and chemical characteristics of individual host Pf-RBCs, parasitophorous vacuole, and cytoplasm. The in situ structural evolution and chemical characteristics of subcellular hemozoin crystals are also elucidated. PMID:23797986

  6. High-resolution three-dimensional imaging of red blood cells parasitized by Plasmodium falciparum and in situ hemozoin crystals using optical diffraction tomography

    NASA Astrophysics Data System (ADS)

    Kim, Kyoohyun; Yoon, HyeOk; Diez-Silva, Monica; Dao, Ming; Dasari, Ramachandra R.; Park, YongKeun

    2014-01-01

    We present high-resolution optical tomographic images of human red blood cells (RBC) parasitized by malaria-inducing Plasmodium falciparum (Pf)-RBCs. Three-dimensional (3-D) refractive index (RI) tomograms are reconstructed by recourse to a diffraction algorithm from multiple two-dimensional holograms with various angles of illumination. These 3-D RI tomograms of Pf-RBCs show cellular and subcellular structures of host RBCs and invaded parasites in fine detail. Full asexual intraerythrocytic stages of parasite maturation (ring to trophozoite to schizont stages) are then systematically investigated using optical diffraction tomography algorithms. These analyses provide quantitative information on the structural and chemical characteristics of individual host Pf-RBCs, parasitophorous vacuole, and cytoplasm. The in situ structural evolution and chemical characteristics of subcellular hemozoin crystals are also elucidated.

  7. Direct Simulation of Evolution and Control of Three-Dimensional Instabilities in Attachment-Line Boundary Layers

    NASA Technical Reports Server (NTRS)

    Joslin, Ronald D.

    1995-01-01

    The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier-Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic- source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in at-plate boundary-layer flows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities.

  8. Three-dimensional image and spatial spectrum analysis of behavior of small animal erythrocytes in optical tweezers

    NASA Astrophysics Data System (ADS)

    Chen, Hui Chi; Shen, Wen-Tai; Kong, Yu-Han; Chuang, Chun-Hao

    2008-02-01

    Because of the softness of membrane, erythrocytes (red blood cell, RBC) have different shapes while being immersed in buffer with different osmotic pressure. While affecting by different viruses and illnesses, RBC may change its shape, or its membrane may become rigid. Moreover, RBC will ford and stretch when it is trapped by optical tweezers. Therefore, the behaviors of RBC in optical tweezers raise more discussion. In this report, we set up an optical tweezers to trap RBC of small animals like feline and canine. By adding a long working distance objective to collect the side-viewing image, a 3-D image system was constructed to detect the motion of trapped RBC. To improve the image quality for side-view, an aperture and narrow glass plate were used. From the video of these images and their spatial spectrum, the shape of trapped RBC was studied.

  9. Binding Energies and Linear and Nonlinear Optical Properties of a Donor Impurity in a Three-Dimensional Quantum Pseudodot

    NASA Astrophysics Data System (ADS)

    Kirak, Muharrem; Yilmaz, Sait

    2013-12-01

    A theoretical study of the electronic properties of the ground state and excited states and the linear and the third-order nonlinear optical properties (i. e., absorption coefficients and refractive indices) in a spherical GaAs pseudodot system is reported. The variational procedure has been employed in determining sublevel energy eigenvalues and their wave functions within the effective mass approximation. Our results indicate that the chemical potential of the electron gas and the minimum value of the pseudoharmonic potential have a great influence on the electrical and optical properties of hydrogenic impurity states. Also, we have found that the magnitudes of the absorption coefficient and the refractive index change of the spherical quantum dot increase for transitions between higher levels.

  10. The development of three-dimensional adjoint method for flow control with blowing in convergent-divergent nozzle flows

    NASA Astrophysics Data System (ADS)

    Sikarwar, Nidhi

    multiple experiments or numerical simulations. Alternatively an inverse design method can be used. An adjoint optimization method can be used to achieve the optimum blowing rate. It is shown that the method works for both geometry optimization and active control of the flow in order to deflect the flow in desirable ways. An adjoint optimization method is described. It is used to determine the blowing distribution in the diverging section of a convergent-divergent nozzle that gives a desired pressure distribution in the nozzle. Both the direct and adjoint problems and their associated boundary conditions are developed. The adjoint method is used to determine the blowing distribution required to minimize the shock strength in the nozzle to achieve a known target pressure and to achieve close to an ideally expanded flow pressure. A multi-block structured solver is developed to calculate the flow solution and associated adjoint variables. Two and three-dimensional calculations are performed for internal and external of the nozzle domains. A two step MacCormack scheme based on predictor- corrector technique is was used for some calculations. The four and five stage Runge-Kutta schemes are also used to artificially march in time. A modified Runge-Kutta scheme is used to accelerate the convergence to a steady state. Second order artificial dissipation has been added to stabilize the calculations. The steepest decent method has been used for the optimization of the blowing velocity after the gradients of the cost function with respect to the blowing velocity are calculated using adjoint method. Several examples are given of the optimization of blowing using the adjoint method.

  11. Erratum: Optical and transport properties in three-dimensional Dirac and Weyl semimetals [Phys. Rev. B 93, 085426 (2016)

    NASA Astrophysics Data System (ADS)

    Tabert, C. J.; Carbotte, J. P.; Nicol, E. J.

    2016-07-01

    Within a Kubo formalism, we study dc transport and ac optical properties of 3D Dirac and Weyl semimetals. Emphasis is placed on the approach to charge neutrality and on the differences between Dirac and Weyl materials. At charge neutrality, the zero-temperature limit of the dc conductivity is not universal and also depends on the residual scattering model employed. However, the Lorenz number L retains its usual value L_0. With increasing temperature, the Wiedemann-Franz law is violated. At high temperatures, L exhibits a new plateau at a value dependent on the details of the scattering rate. Such details can also appear in the optical conductivity, both in the Drude response and interband background. In the clean limit, the interband background is linear in photon energy and always extrapolates to the origin. This background can be shifted to the right through the introduction of a massless gap. In this case, the extrapolation can cut the axis at a finite photon energy as is observed in some experiments. It is also of interest to differentiate between the two types of Weyl semimetals: those with broken time-reversal symmetry and those with broken spatial-inversion symmetry. We show that, while the former will follow the same behaviour as the 3D Dirac semimetals, for the zero magnetic field properties discussed here, the latter type will show a double step in the optical conductivity at finite doping and a single absorption edge at charge neutrality. The Drude conductivity is always finite in this case, even at charge neutrality.

  12. The skeleton buildup technique: a systematic approach to the three-dimensional control of shade and shape.

    PubMed

    McLaren, E A

    1998-01-01

    Due to the limitations of current shade-matching systems, shade communication has proven inadequate. Techniques for the fabrication of porcelain crowns that match the natural definition must address numerous factors. While all-ceramic restorations are indicated for the rehabilitation of the anterior dentition, these modalities are problematic in the restoration of teeth with discolored substrates. This article presents a systematic procedure for the three-dimensional fabrication of porcelain restorations. Techniques for building porcelain and altering the translucency of ceramic cores are also presented.

  13. Combined three-dimensional magnetic resonance guided optical spectroscopy for functional and molecular imaging of human breast cancer

    NASA Astrophysics Data System (ADS)

    Mastanduno, Michael A.; Davis, Scott C.; Jiang, Shudong; diFlorio-Alexander, Roberta; Pogue, Brian W.; Paulsen, Keith D.

    2011-07-01

    Dynamic contrast enhanced magnetic resonance is used to image high-risk patients for breast cancer because of its higher sensitivity to tumors than mammography. We focus on Near Infrared Spectroscopy (NIRS) imaging and Fluorescence Molecular Tomography (FMT), emerging imaging techniques that non-invasively quantify optical properties of total hemoglobin, oxygen saturation, water content, scattering, lipid concentration and endogenous Protoporphyrin IX (PpIX) emission. We present methods on combining the synergistic attributes of DCE-MR, NIRS, and FMT for in-vivo imaging of breast cancer in three dimensions using a custom optical MR breast coil and diffusion based light modeling software, NIRFAST. We present example results from a breast cancer patient. Preliminary results show elevated hemoglobin values and water fraction. Fluorescence values in the tumor region, however, were not always elevated above the surrounding tissue as we had expected. The additional information gained from NIRS and FMT may improve the ability to distinguish between malignant and benign lesions during MR imaging. These dual modality instruments will provide complex anatomical and molecular prognostic information, and may decrease the number of biopsies, thereby improving patient care.

  14. Design, analysis, and initial testing of a fiber-optic shear gage for three-dimensional, high-temperature flows

    NASA Astrophysics Data System (ADS)

    Orr, Matthew W.

    This investigation concerns the design, analysis, and initial testing of a new, two-component wall shear gage for 3D, high-temperature flows. This gage is a direct-measuring, non-nulling design with a round head surrounded by a small gap. Two flexure wheels are used to allow small motions of the floating head. Fiber-optic displacement sensors measure how far the polished faces of counterweights on the wheels move in relation to a fixed housing as the primary measurement system. No viscous damping was required. The gage has both fiber-optic instrumentation and strain gages mounted on the flexures for validation of the newer fiber optics. The sensor is constructed of Haynes RTM 230RTM, a high-temperature nickel alloy. The gage housing is made of 316 stainless steel. All components of the gage in pure fiber-optic form can survive to a temperature of 1073 K. The bonding methods of the backup strain gages limit their maximum temperature to 473 K. The dynamic range of the gage is from 0--500 Pa (0--10g) and higher shears can be measured by changing the floating head size. Extensive use of finite element modeling was critical to the design and analysis of the gage. Static structural, modal, and thermal analyses were performed on the flexures using the ANSYS finite element package. Static finite element analysis predicted the response of the flexures to a given load, and static calibrations using a direct force method confirmed these results. Finite element modal analysis results were within 16.4% for the first mode and within 30% for the second mode when compared with the experimentally determined modes. Vibration characteristics of the gage were determined from experimental free vibration data after the gage was subjected to an impulse. Uncertainties in the finished geometry make this level of error acceptable. A transient thermal analysis examined the effects of a very high heat flux on the exposed head of the gage. The 100,000 W/m2 heat flux used in this analysis is

  15. Monitoring the response to neoadjuvant hormone therapy for locally advanced breast cancer using three-dimensional time-resolved optical mammography

    NASA Astrophysics Data System (ADS)

    Enfield, Louise; Cantanhede, Gabriel; Douek, Michael; Ramalingam, Vernie; Purushotham, Arnie; Hebden, Jem; Gibson, Adam

    2013-05-01

    Optical mammography is a functional imaging technique that uses near-infrared light to produce three-dimensional breast images of tissue oxygen saturation and hemoglobin concentration. It has been used to monitor the response to neoadjuvant chemotherapy in breast cancer patients. We present the first results on monitoring tumor response to hormone therapy using optical mammography. We present three case studies from postmenopausal women treated with neoadjuvant hormone therapy for locally advanced breast cancer. The women were scanned before starting treatment, once during treatment, and then before surgery. Changes in physiological and optical properties within the tumor and in the rest of the breast were evaluated. At the time of surgery, two patients partially responded to treatment and one did not respond. The patients that partially responded on ultrasound revealed a corresponding recovery to normal in the hemoglobin concentration images, whereas the nonresponder indicated an increase in hemoglobin concentration in the tumor compared to her pretreatment images. These case studies suggest that optical imaging of the breast during neoadjuvant hormone treatment can provide potentially valuable information, and that physiological changes within the tumor can be seen in response to treatment.

  16. Asymptotic analysis of: I. Wave propagation in dispersive optical media with quadratic nonlinearity. II. A hypersonic wing with three-dimensional self-similarity

    SciTech Connect

    Kalocsai, A.G.

    1992-12-31

    An asymptotic analysis is presented for two distinct and independent problems: (I) Wave propagation in dispersive optical media with quadratic nonlinearity (II) Hypersonic flows with three dimensional self-similarity. In the optics problem, we at first study single and multiple input propagating waves at frequencies away from dielectric resonances. Here we compare the Slowly Varying Envelope Approximation to the Method of Multiple Scales and show that the Method of Multiple Scales is a superior technique that can be applied self consistently to any perturbation order which in turn predicts new physical effects. For the single slowly modulated input wave problem, under appropriate conditions, we shown that at the O({epsilon}{sup 2}) perturbation, we obtain the cubic nonlinear Schrodinger equation. This means that for the single input wave propagating in a quadratic nonlinear medium, self-modulation effects and soliton behavior may be observed depending on the boundary conditions. For the single input wave near a classical dielectric resonance, we find that the wave number becomes amplitude dependent. The method of multiple scales is replaced by Whitham`s averaged Lagrangian. We derive the associated modulated envelope equations. We investigate an effective medium regime and the full nonlinear problem. The hypersonic flow problem requires the use of asymptotic matching that arises from the geometry from the problem. Here the pressure field and lift to drag C{sup 3/2}{sub L}/C{sub D} is evaluated for a wide delta wing with small power law curvature. Use is made of Hypersonic Small Disturbance Theory and three dimensional power law similarity. It is shown that an improvement for C{sup 3/2}{sub L}/C{sub D} occurs for wings with power law curvatures greater than one, when compared to flat delta wings. This improvement in performance agrees qualitatively with other types of concave wings.

  17. Comparison of optical coherence tomography, microcomputed tomography, and histology at a three-dimensionally imaged trabecular bone sample

    NASA Astrophysics Data System (ADS)

    Kasseck, Christoph; Kratz, Marita; Torcasio, Antonia; Gerhardt, Nils C.; van Lenthe, G. Harry; Gambichler, Thilo; Hoffmann, Klaus; Jones, David B.; Hofmann, Martin R.

    2010-07-01

    We investigate optical coherence tomography (OCT) as a method for imaging bone. The OCT images are compared directly to those of the standard methods of bone histology and microcomputed tomography (μCT) on a single, fixed human femoral trabecular bone sample. An advantage of OCT over bone histology is its noninvasive nature. OCT also images the lamellar structure of trabeculae at slightly higher contrast than normal bone histology. While μCT visualizes the trabecular framework of the whole sample, OCT can image additionally cells with a penetration depth limited approximately to 1 mm. The most significant advantage of OCT, however, is the absence of toxic effects (no ionizing radiation), i.e., continuous images may be made and individual cell tracking may be performed. The penetration depth of OCT, however, limits its use to small animal models and small bone organ cultures.

  18. In vivo early retinal structural alterations following laser photocoagulation using three-dimensional spectral domain optical coherence tomography.

    PubMed

    Saxena, Sandeep; Mishra, Nibha; Ruia, Surabhi; Akduman, Levent

    2016-01-01

    To study the retinal structural alterations and surface topography of retinal pigment epithelium (RPE) immediately following laser photocoagulation up to day 7. Cross-sectional retinal imaging and RPE segmentation maps on spectral domain optical coherence tomography were obtained immediately at hour 1, day 1, day 4 and day 7 following 532 nm neodymium:YAG laser photocoagulation in a 56-year-old male patient for branch retinal vein occlusion. Immediately postlaser, loss of reflectivity of all the retinal layers was observed. At hour 1, hyper-reflectivity of outer retinal layers was observed with increase in hyporeflective spaces by day 1. Immediately postlaser, pitting of the RPE was observed on surface topography which regressed at day 1. On day 4, smooth RPE surface topography was observed with the occurrence of small elevated areas on day 7. The present report provides an insight into the in vivo changes in the retinal structure and RPE surface topography after laser photocoagulation. PMID:27402655

  19. In vivo early detection of smoke-induced airway injury using three-dimensional swept-source optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Yin, Jiechen; Liu, Gangjun; Zhang, Jun; Yu, Lingfeng; Mahon, Sari; Mukai, David; Brenner, Matthew; Chen, Zhongping

    2009-11-01

    We report on the feasibility of rapid, high-resolution, 3-D swept-source optical coherence tomography (SSOCT) to detect early airway injury changes following smoke inhalation exposure in a rabbit model. The SSOCT system obtains 3-D helical scanning using a microelectromechanical system motor-based endoscope. Real-time 2-D data processing and image display at the speed of 20 frames/s are achieved by adopting the technique of parallel computing. Longitudinal images are reconstructed via an image processing algorithm to remove motion artifacts caused by ventilation and pulse. Quantitative analyses of tracheal airway thickness as well as thickness distribution along tracheal circumference are also performed based on the comprehensive 3-D volumetric data.

  20. In vivo three-dimensional optical coherence tomography and multiphoton microscopy in a mouse model of ovarian neoplasia

    NASA Astrophysics Data System (ADS)

    Watson, Jennifer M.; Marion, Samuel L.; Rice, Photini Faith; Bentley, David L.; Besselsen, David; Utzinger, Urs; Hoyer, Patricia B.; Barton, Jennifer K.

    2013-03-01

    Our goal is to use optical coherence tomography (OCT) and multiphoton microscopy (MPM) to detect early tumor development in a mouse model of ovarian neoplasia. We hope to use information regarding early tumor development to create a diagnostic test for high-risk patients. In this study we collect in vivo images using OCT, second harmonic generation and two-photon excited fluorescence from non-vinylcyclohexene diepoxide (VCD)-dosed and VCD-dosed mice. VCD causes follicular apoptosis (simulating menopause) and leads to tumor development. Using OCT and MPM we visualized the ovarian microstructure and were able to see differences between non-VCD-dosed and VCD-dosed animals. This leads us to believe that OCT and MPM may be useful for detecting changes due to early tumor development.

  1. Three-dimensional inverse problem of geometrical optics: a mathematical comparison between Fermat's principle and the eikonal equation.

    PubMed

    Borghero, Francesco; Demontis, Francesco

    2016-09-01

    In the framework of geometrical optics, we consider the following inverse problem: given a two-parameter family of curves (congruence) (i.e., f(x,y,z)=c1,g(x,y,z)=c2), construct the refractive-index distribution function n=n(x,y,z) of a 3D continuous transparent inhomogeneous isotropic medium, allowing for the creation of the given congruence as a family of monochromatic light rays. We solve this problem by following two different procedures: 1. By applying Fermat's principle, we establish a system of two first-order linear nonhomogeneous PDEs in the unique unknown function n=n(x,y,z) relating the assigned congruence of rays with all possible refractive-index profiles compatible with this family. Moreover, we furnish analytical proof that the family of rays must be a normal congruence. 2. By applying the eikonal equation, we establish a second system of two first-order linear homogeneous PDEs whose solutions give the equation S(x,y,z)=const. of the geometric wavefronts and, consequently, all pertinent refractive-index distribution functions n=n(x,y,z). Finally, we make a comparison between the two procedures described above, discussing appropriate examples having exact solutions. PMID:27607492

  2. Motion correction of in vivo three-dimensional optical coherence tomography of human skin using a fiducial marker

    PubMed Central

    Liew, Yih Miin; McLaughlin, Robert A.; Wood, Fiona M.; Sampson, David D.

    2012-01-01

    This paper presents a novel method based on a fiducial marker for correction of motion artifacts in 3D, in vivo, optical coherence tomography (OCT) scans of human skin and skin scars. The efficacy of this method was compared against a standard cross-correlation intensity-based registration method. With a fiducial marker adhered to the skin, OCT scans were acquired using two imaging protocols: direct imaging from air into tissue; and imaging through ultrasound gel into tissue, which minimized the refractive index mismatch at the tissue surface. The registration methods were assessed with data from both imaging protocols and showed reduced distortion of skin features due to motion. The fiducial-based method was found to be more accurate and robust, with an average RMS error below 20 µm and success rate above 90%. In contrast, the intensity-based method had an average RMS error ranging from 36 to 45 µm, and a success rate from 50% to 86%. The intensity-based algorithm was found to be particularly confounded by corrugations in the skin. By contrast, tissue features did not affect the fiducial-based method, as the motion correction was based on delineation of the flat fiducial marker. The average computation time for the fiducial-based algorithm was approximately 21 times less than for the intensity-based algorithm. PMID:22876343

  3. Spectral domain optical coherence tomography for in-vivo three-dimensional retinal imaging of small animals

    NASA Astrophysics Data System (ADS)

    Ruggeri, Marco; Wehbe, Hassan; Jiao, Shuliang; Gregori, Giovanni; Jockovich, Maria E.; Hackam, Abigail; Duan, Yuanli; Puliafito, Carmen A.

    2007-02-01

    The purpose of this study is to demonstrate the application of ultrahigh-resolution Spectral Domain Optical Coherence Tomography (SD-OCT) for non contact in vivo imaging of the retina of small animals and quantitative retinal information extraction using 3D segmentation of the OCT images. An ultrahigh-resolution SD-OCT system was specifically designed for in vivo retinal imaging of small animal. En face fundus image was constructed from the measured OCT data, which enables precise registration of the OCT images on the fundus. 3D segmentation algorithms were developed for the calculation of retinal thickness map. High quality OCT images of the retina of mice (B6/SJLF2 for normal retina, Rho -/- for photoreceptor degeneration and LH BETAT AG for retinoblastoma) and rats (Wistar for normal retina) were acquired, where all the retinal layers can be clearly recognized. The calculated retinal thickness map makes successful quantitative comparison of the retinal thickness distribution between normal and degenerative mouse retina. The capabilities of the OCT system provide a valuable tool for longitudinal studies of small animal models of ocular diseases.

  4. Quantification of facial movements by optical instruments: surface laser scanning and optoelectronic three-dimensional motion analyzer.

    PubMed

    Sidequersky, Fernanda Vincia; Verzé, Laura; Mapelli, Andrea; Ramieri, Guglielmo Amedeo; Sforza, Chiarella

    2014-01-01

    The objective of this study was to assess the accuracy of displacements of tracing landmarks in standardized facial movements. Forty healthy persons were evaluated in 2 different groups (20 men and 20 women, aged 18-30 years) with optoelectronic motion analyzer and surface laser scanning. The displacements of tracing landmarks in brow lift and smile were calculated, and the 2 methods (optoelectronic motion analyzer and surface laser scanning) were compared in healthy persons. Side-related differences were found in the tracing landmark (superciliare) during brow lift movements between both methods (the largest movements were found on the right side, P = 0.044), whereas in smile movements the tracing landmark cheilion did not show significant differences between the 2 sides. In both movements, the differences of the tracing landmark displacements between the 2 systems and sexes were on average less than 2 mm, without statistically significant differences (P > 0.05). In conclusion, normal young adult men and women had similar standardized facial movements. The 2 analyzed movements can be measured by both optical instruments with comparable results.

  5. Fully automatic three-dimensional visualization of intravascular optical coherence tomography images: methods and feasibility in vivo

    PubMed Central

    Ughi, Giovanni J; Adriaenssens, Tom; Desmet, Walter; D’hooge, Jan

    2012-01-01

    Intravascular optical coherence tomography (IV-OCT) is an imaging modality that can be used for the assessment of intracoronary stents. Recent publications pointed to the fact that 3D visualizations have potential advantages compared to conventional 2D representations. However, 3D imaging still requires a time consuming manual procedure not suitable for on-line application during coronary interventions. We propose an algorithm for a rapid and fully automatic 3D visualization of IV-OCT pullbacks. IV-OCT images are first processed for the segmentation of the different structures. This also allows for automatic pullback calibration. Then, according to the segmentation results, different structures are depicted with different colors to visualize the vessel wall, the stent and the guide-wire in details. Final 3D rendering results are obtained through the use of a commercial 3D DICOM viewer. Manual analysis was used as ground-truth for the validation of the segmentation algorithms. A correlation value of 0.99 and good limits of agreement (Bland Altman statistics) were found over 250 images randomly extracted from 25 in vivo pullbacks. Moreover, 3D rendering was compared to angiography, pictures of deployed stents made available by the manufacturers and to conventional 2D imaging corroborating visualization results. Computational time for the visualization of an entire data sets resulted to be ~74 sec. The proposed method allows for the on-line use of 3D IV-OCT during percutaneous coronary interventions, potentially allowing treatments optimization. PMID:23243578

  6. Robot-assisted three-dimensional registration for cochlear implant surgery using a common-path swept-source optical coherence tomography probe

    NASA Astrophysics Data System (ADS)

    Gurbani, Saumya S.; Wilkening, Paul; Zhao, Mingtao; Gonenc, Berk; Cheon, Gyeong Woo; Iordachita, Iulian I.; Chien, Wade; Taylor, Russell H.; Niparko, John K.; Kang, Jin U.

    2014-05-01

    Cochlear implantation offers the potential to restore sensitive hearing in patients with severe to profound deafness. However, surgical placement of the electrode array within the cochlea can produce trauma to sensorineural components, particularly if the initial turn of the cochlea is not successfully navigated as the array is advanced. In this work, we present a robot-mounted common-path swept-source optical coherence tomography endoscopic platform for three-dimensional (3-D) optical coherence tomography (OCT) registration and preoperative surgical planning for cochlear implant surgery. The platform is composed of a common-path 600-μm diameter fiber optic rotary probe attached to a five degrees of freedom robot capable of 1 μm precision movement. The system is tested on a dry fixed ex vivo human temporal bone, and we demonstrate the feasibility of a 3-D OCT registration of the cochlea to accurately describe the spatial and angular profiles of the canal formed by the scala tympani into the first cochlear turn.

  7. Three-dimensional metamaterials

    DOEpatents

    Burckel, David Bruce

    2012-06-12

    A fabrication method is capable of creating canonical metamaterial structures arrayed in a three-dimensional geometry. The method uses a membrane suspended over a cavity with predefined pattern as a directional evaporation mask. Metallic and/or dielectric material can be evaporated at high vacuum through the patterned membrane to deposit resonator structures on the interior walls of the cavity, thereby providing a unit cell of micron-scale dimension. The method can produce volumetric metamaterial structures comprising layers of such unit cells of resonator structures.

  8. Coupling sky images with three-dimensional radiative transfer models: a new method to estimate cloud optical depth

    NASA Astrophysics Data System (ADS)

    Mejia, F. A.; Kurtz, B.; Murray, K.; Hinkelman, L. M.; Sengupta, M.; Xie, Y.; Kleissl, J.

    2015-10-01

    A method for retrieving cloud optical depth (τc) using a ground-based sky imager (USI) is presented. The Radiance Red-Blue Ratio (RRBR) method is motivated from the analysis of simulated images of various τc produced by a 3-D Radiative Transfer Model (3DRTM). From these images the basic parameters affecting the radiance and RBR of a pixel are identified as the solar zenith angle (θ0), τc, solar pixel angle/scattering angle (ϑs), and pixel zenith angle/view angle (ϑz). The effects of these parameters are described and the functions for radiance, Iλ(τc, θ0, ϑs, ϑz) and the red-blue ratio, RBR(τc, θ0, ϑs, ϑz) are retrieved from the 3DRTM results. RBR, which is commonly used for cloud detection in sky images, provides non-unique solutions for τc, where RBR increases with τc up to about τc = 1 (depending on other parameters) and then decreases. Therefore, the RRBR algorithm uses the measured Iλmeas(ϑs, ϑz), in addition to RBRmeas(ϑs, ϑz) to obtain a unique solution for τc. The RRBR method is applied to images taken by a USI at the Oklahoma Atmospheric Radiation Measurement program (ARM) site over the course of 220 days and validated against measurements from a microwave radiometer (MWR); output from the Min method for overcast skies, and τc retrieved by Beer's law from direct normal irradiance (DNI) measurements. A τc RMSE of 5.6 between the Min method and the USI are observed. The MWR and USI have an RMSE of 2.3 which is well within the uncertainty of the MWR. An RMSE of 0.95 between the USI and DNI retrieved τc is observed. The procedure developed here provides a foundation to test and develop other cloud detection algorithms.

  9. Cryopreservation of rat hepatocytes in a three-dimensional culture configuration using a controlled-rate freezing device.

    PubMed

    Russo, M J; Toner, M

    1999-01-01

    From engineered tissues to transfected cell lines, the long term storage of living biologicals is desirable for a variety of medical, scientific, economic, and regulatory concerns, including transport, the expense of development, repeatability issues, and the point of use. Currently, the best option is cryogenic storage, placing the biomaterials in suspended animation at very low temperatures (-196°C), halting all chemical reactions, limiting genetic drift, and ensuring the maintenance of cell viability and function upon thawing (1). Obtaining such an advantageous state, however, can be a difficult achievement. This problem becomes further complicated as we move toward next generation multicomponent products such as engineered skin and cartilage substitutes, composed of multiple cell types oriented in complicated three-dimensional geometries within an extracellular matrix scaffold (2-4).

  10. Three Dimensional Dirac Semimetals

    NASA Astrophysics Data System (ADS)

    Zaheer, Saad

    2014-03-01

    Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.

  11. Analysis of magneto-optical properties for three-dimensional photonic crystals in high-symmetry arrangement doped by metamaterials and uniaxial materials

    NASA Astrophysics Data System (ADS)

    Yu, Bing; Li, Heming; Wang, Shenyun; Wan, Fayu; Ge, Junxiang

    2016-11-01

    In this paper, we use a modified plane wave expansion (PWE) method to investigate the properties of photonic band gaps (PBGs) for the extraordinary mode in the three-dimensional (3D) photonic crystals (PCs) which are composed of the anisotropic dielectric (the uniaxial materials) spheres immersed in the homogeneous metamaterials (epsilon-negative materials) background with high-symmetry (body-centered-cubic) lattices, as the magneto-optical Voigt effects are considered. The equations for calculating the PBGs in the first irreducible Brillouin zone are theoretically derived. It is numerically illustrated that the anisotropic PBGs and two flattened band regions can be achieved. The influences of the ordinary-refractive index, extraordinary-refractive index, filling factor of dielectric spheres, electronic plasma frequency and cyclotron frequency on the magneto-optical properties of such 3D PCs also are studied in detail, respectively, and some corresponding physical explanations are given. The numerical results demonstrate that the anisotropy can open partial band gaps in the proposed PCs, and the complete PBGs can be obtained compared with the conventional PCs only containing the isotropic material with similar structures. The bandwidths of PBGs can be tuned by introducing the epsilon-negative materials into such PCs containing the uniaxial materials. The anisotropic PBGs can be manipulated by the parameters as mentioned above. As the proposed PCs with high-symmetry lattices, the complete PBGs can be obtained by introducing the uniaxial materials.

  12. Three-dimensional diffuse optical tomography in the parallel plane transmission geometry: evaluation of a hybrid frequency domain/continuous wave clinical system for breast imaging.

    PubMed

    Culver, J P; Choe, R; Holboke, M J; Zubkov, L; Durduran, T; Slemp, A; Ntziachristos, V; Chance, B; Yodh, A G

    2003-02-01

    Three-dimensional diffuse optical tomography (DOT) of breast requires large data sets for even modest resolution (1 cm). We present a hybrid DOT system that combines a limited number of frequency domain (FD) measurements with a large set of continuous wave (cw) measurements. The FD measurements are used to quantitatively determine tissue averaged absorption and scattering coefficients. The larger cw data sets (10(5) measurements) collected with a lens coupled CCD, permit 3D DOT reconstructions of a 1-liter tissue volume. To address the computational complexity of large data sets and 3D volumes we employ finite difference based reconstructions computed in parallel. Tissue phantom measurements evaluate imaging performance. The tests include the following: point spread function measures of resolution, characterization of the size and contrast of single objects, field of view measurements and spectral characterization of constituent concentrations. We also report in vivo measurements. Average tissue optical properties of a healthy breast are used to deduce oxy- and deoxy-hemoglobin concentrations. Differential imaging with a tumor simulating target adhered to the surface of a healthy breast evaluates the influence of physiologic fluctuations on image noise. This tomography system provides robust, quantitative, full 3D image reconstructions with the advantages of high data throughput, single detector-tissue coupling path, and large (1L) imaging domains. In addition, we find that point spread function measurements provide a useful and comprehensive representation of system performance.

  13. Three-dimensional printing models improve understanding of spinal fracture--A randomized controlled study in China.

    PubMed

    Li, Zhenzhu; Li, Zefu; Xu, Ruiyu; Li, Meng; Li, Jianmin; Liu, Yongliang; Sui, Dehua; Zhang, Wensheng; Chen, Zheng

    2015-06-23

    Three-dimensional printing (3 Dp) is being increasingly used in medical education. Although the use of such lifelike models is beneficial, well-powered, randomized studies supporting this statement are scarce. Two spinal fracture simulation models were generated by 3 Dp. Altogether, 120 medical students (54.2% females) were randomized into three teaching module groups [two-dimensional computed tomography images (CT), 3D, or 3 Dp] and asked to answer 10 key anatomical and 4 evaluative questions. Students in the 3 Dp or 3D group performed significantly better than those in the CT group, although males in the 3D group scored higher than females. Students in the 3 Dp group were the first to answer all questions, and there were no sex-related differences. Pleasure, assistance, effect, and confidence were more predominant in students in the 3 Dp group than in those in the 3D and CT groups. This randomized study revealed that the 3 Dp model markedly improved the identification of complex spinal fracture anatomy by medical students and was equally appreciated and comprehended by both sexes. Therefore, the lifelike fracture model made by 3 Dp technology should be used as a means of premedical education.

  14. The Repeatability Assessment of Three-Dimensional Capsule-Intraocular Lens Complex Measurements by Means of High-Speed Swept-Source Optical Coherence Tomography

    PubMed Central

    Chang, Pingjun; Li, Jin; Savini, Giacomo; Huang, Jinhai; Huang, Shenghai; Zhao, Yinying; Liao, Na; Lin, Lei; Yu, Xiaoyu; Zhao, Yun-e

    2015-01-01

    Purpose To rebuild the three-dimensional (3-D) model of the anterior segment by high-speed swept-source optical coherence tomography (SSOCT) and evaluate the repeatability of measurement for the parameters of capsule-intraocular lens (C-IOL) complex. Methods Twenty-two pseudophakic eyes from 22 patients were enrolled. Three continuous SSOCT measurements were performed in all eyes and the tomograms obtained were used for 3-D reconstruction. The output data were used to evaluate the measurement repeatability. The parameters included postoperative aqueous depth (PAD), the area and diameter of the anterior capsule opening (Area and D), IOL tilt (IOL-T), horizontal, vertical, and space decentration of the IOL, anterior capsule opening, and IOL-anterior capsule opening. Results PAD, IOL-T, Area, D, and all decentration measurements showed high repeatability. Repeated measure analysis showed there was no statistically significant difference among the three continuous measurements (all P > .05). Pearson correlation analysis showed high correlation between each pair of them (all r >0.90, P<0.001). ICCs were all more than 0.9 for all parameters. The 95% LoAs of all parameters were narrow for comparison of three measurements, which showed high repeatability for three measurements. Conclusion SSOCT is available to be a new method for the 3-D measurement of C-IOL complex after cataract surgery. This method presented high repeatability in measuring the parameters of the C-IOL complex. PMID:26600254

  15. Understanding three-dimensional spatial relationship between the mouse second polar body and first cleavage plane with full-field optical coherence tomography.

    PubMed

    Zheng, Jing-gao; Huo, Tiancheng; Chen, Tianyuan; Wang, Chengming; Zhang, Ning; Tian, Ning; Zhao, Fengying; Lu, Danyu; Chen, Dieyan; Ma, Wanyun; Sun, Jia-lin; Xue, Ping

    2013-01-01

    The morphogenetic relationship between early patterning and polarity formation is of fundamental interest and remains a controversial issue in preimplantation embryonic development. We use a label-free three-dimensional (3-D) imaging technique of full-field optical coherence tomography (FF-OCT) successfully for the first time to study the dynamics of developmental processes in mouse preimplantation lives. Label-free 3-D subcellular time-lapse images are demonstrated to investigate 3-D spatial relationship between the second polar body (2PB) and the first cleavage plane. By using FF-OCT together with quantitative study, we show that only 25% of the predicted first cleavage planes, defined by the apposing plane of two pronuclei, pass through the 2PB. Also only 27% of the real cleavage planes pass through the 2PB. These results suggest that the 2PB is not a convincing spatial cue for the event of the first cleavage. Our studies demonstrate the feasibility of FF-OCT in providing new insights and potential breakthroughs to the controversial issues of early patterning and polarity in mammalian developmental biology. PMID:23238420

  16. Evaluation of the usefulness of three-dimensional optical coherence tomography in a guinea pig model of endolymphatic hydrops induced by surgical obliteration of the endolymphatic duct

    NASA Astrophysics Data System (ADS)

    Cho, Nam Hyun; Lee, Jang Woo; Cho, Jin-ho; Kim, Jeehyun; Jang, Jeong Hun; Jung, Woonggyu

    2015-03-01

    Optical coherence tomography (OCT) has advanced significantly over the past two decades and is currently used extensively to monitor the internal structures of organs, particularly in ophthalmology and dermatology. We used ethylenediamine tetra-acetic acid (EDTA) to decalcify the bony walls of the cochlea and investigated the inner structures by deep penetration of light into the cochlear tissue using OCT on a guinea pig model of endolymphatic hydrops (EH), induced by surgical obliteration of the endolymphatic duct. The structural and functional changes associated with EH were identified using OCT and auditory brainstem response tests, respectively. We also evaluated structural alterations in the cochlea using three-dimensional reconstruction of the OCT images, which clearly showed physical changes in the cochlear structures. Furthermore, we found significant anatomical variations in the EH model and conducted graphical analysis by strial atrophy for comparison. The physical changes included damage to and flattening of the organ of Corti-evidence of Reissner's membrane distention-and thinning of the lateral wall. These results indicate that observation of EDTA-decalcified cochlea using OCT is significant in examination of gradual changes in the cochlear structures that are otherwise not depicted by hematoxylin and eosin staining.

  17. Three dimensional ultrasonic imaging

    SciTech Connect

    Thomas, G. H.; Benson, S.; Crawford, S.

    1993-03-01

    Ultrasonic nondestructive evaluation techniques interrogate components with high frequency acoustic energy. A transducer generates the acoustic energy and converts acoustic energy to electrical signals. The acoustic energy is reflected by abrupt changes in modulus and/or density which can be caused by a defect. Thus defects reflect the ultrasonic energy which is converted into electrical signals. Ultrasonic evaluation typically provides a two dimensional image of internal defects. These images are either planar views (C-scans) or cross-sectional views (B-scans). The planar view is generated by raster scanning an ultrasonic transducer over the component and capturing the amplitude of internal reflections. Depth information is generally ignored. The cross-sectional view is generated by scanning the transducer along a single line and capturing the amplitude and time of flight for each internal reflection. The amplitude and time of flight information is converted into an image of the cross section of the component where the scan was performed. By fusing the C-scan information with the B-scan information a three dimension image of the internal structure of the component can be produced. The three dimensional image can be manipulated by rotating and slicing to produce the optimal view of the internal structure. The high frequency ultrasonic energy requires a liquid coupling media and thus applications for imaging in liquid environments are well suited to ultrasonic techniques. Examples of potential ultrasonic imaging applications are: Inside liquid filled tanks, inside the human body, and underwater.

  18. The properties of the extraordinary mode and surface plasmon modes in the three-dimensional magnetized plasma photonic crystals based on the magneto-optical Voigt effects

    SciTech Connect

    Zhang, Hai-Feng E-mail: lsb@nuaa.edu.cn; Liu, Shao-Bin E-mail: lsb@nuaa.edu.cn; Tang, Yi-Jun

    2014-06-15

    In this paper, the properties of the extraordinary mode and surface plasmon modes in the three-dimensional (3D) magnetized plasma photonic crystals (MPPCs) with face-centered-cubic lattices that are composed of the core tellurium (Te) spheres with surrounded by the homogeneous magnetized plasma shells inserted in the air, are theoretically investigated in detail by the plane wave expansion method, as the magneto-optical Voigt effects of magnetized plasma are considered (the incidence electromagnetic wave vector is perpendicular to the external magnetic field at any time). The optical switching or wavelength division multiplexer can be realized by the proposed 3D MPPCs. Our analyses demonstrate that the complete photonic band gaps (PBGs) and two flatbands regions for the extraordinary mode can be observed obviously. PBGs can be tuned by the radius of core Te sphere, the plasma density and the external magnetic field. The flatbands regions are determined by the existence of surface plasmon modes. Numerical simulations also show that if the thickness of magnetized plasma shell is larger than a threshold value, the band structures of the extraordinary mode will be similar to those obtained from the same structure containing the pure magnetized plasma spheres. In this case, the band structures also will not be affected by the inserted core spheres. It is also provided that the upper edges of two flatbands regions will not depend on the topology of lattice. However, the frequencies of lower edges of two flatbands regions will be convergent to the different constants for different lattices, as the thickness of magnetized plasma shell is close to zero.

  19. Performance of asynchronous fiber-optic code division multiple access system based on three-dimensional wavelength/time/space codes and its link analysis.

    PubMed

    Singh, Jaswinder

    2010-03-10

    A novel family of three-dimensional (3-D) wavelength/time/space codes for asynchronous optical code-division-multiple-access (CDMA) systems with "zero" off-peak autocorrelation and "unity" cross correlation is reported. Antipodal signaling and differential detection is employed in the system. A maximum of [(W x T+1) x W] codes are generated for unity cross correlation, where W and T are the number of wavelengths and time chips used in the code and are prime. The conditions for violation of the cross-correlation constraint are discussed. The expressions for number of generated codes are determined for various code dimensions. It is found that the maximum number of codes are generated for S < or = min(W,T), where W and T are prime and S is the number of space channels. The performance of these codes is compared to the earlier reported two-dimensional (2-D)/3-D codes for asynchronous systems. The codes have a code-set-size to code-size ratio greater than W/S. For instance, with a code size of 2065 (59 x 7 x 5), a total of 12,213 users can be supported, and 130 simultaneous users at a bit-error rate (BER) of 10(-9). An arrayed-waveguide-grating-based reconfigurable encoder/decoder design for 2-D implementation for the 3-D codes is presented so that the need for multiple star couplers and fiber ribbons is eliminated. The hardware requirements of the coders used for various modulation/detection schemes are given. The effect of insertion loss in the coders is shown to be significantly reduced with loss compensation by using an amplifier after encoding. An optical CDMA system for four users is simulated and the results presented show the improvement in performance with the use of loss compensation.

  20. The properties of the extraordinary mode and surface plasmon modes in the three-dimensional magnetized plasma photonic crystals based on the magneto-optical Voigt effects

    NASA Astrophysics Data System (ADS)

    Zhang, Hai-Feng; Liu, Shao-Bin; Tang, Yi-Jun

    2014-06-01

    In this paper, the properties of the extraordinary mode and surface plasmon modes in the three-dimensional (3D) magnetized plasma photonic crystals (MPPCs) with face-centered-cubic lattices that are composed of the core tellurium (Te) spheres with surrounded by the homogeneous magnetized plasma shells inserted in the air, are theoretically investigated in detail by the plane wave expansion method, as the magneto-optical Voigt effects of magnetized plasma are considered (the incidence electromagnetic wave vector is perpendicular to the external magnetic field at any time). The optical switching or wavelength division multiplexer can be realized by the proposed 3D MPPCs. Our analyses demonstrate that the complete photonic band gaps (PBGs) and two flatbands regions for the extraordinary mode can be observed obviously. PBGs can be tuned by the radius of core Te sphere, the plasma density and the external magnetic field. The flatbands regions are determined by the existence of surface plasmon modes. Numerical simulations also show that if the thickness of magnetized plasma shell is larger than a threshold value, the band structures of the extraordinary mode will be similar to those obtained from the same structure containing the pure magnetized plasma spheres. In this case, the band structures also will not be affected by the inserted core spheres. It is also provided that the upper edges of two flatbands regions will not depend on the topology of lattice. However, the frequencies of lower edges of two flatbands regions will be convergent to the different constants for different lattices, as the thickness of magnetized plasma shell is close to zero.

  1. Technique for designing and evaluating probe caps used in optical topography of infants using a real head model based on three dimensional magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Hirabayashi, Yukiko; Sato, Hiroki; Uchida-Ota, Mariko; Nakai, Akio; Maki, Atsushi

    2008-06-01

    We have developed an effective technique for aiding the design and evaluating the performance of the probe caps used to perform optical topography (OT) on infants. To design and evaluate a probe cap, it is necessary to determine the measurement positions for conducting OT on the brain surface of subjects. One technique for determining these positions on the brain surface is to find their three-dimensional (3D) coordinates using a 3D magnetic space digitizer, which consists of a 3D magnetic source and a 3D magnetic sensor. The problem with this technique is that it takes a long time to determine all the measurement points on the subject's head and it is difficult to use with infants. It is a particular problem with infants who cannot support their own heads. Therefore, we have developed a real model of an infant subject's head based on 3D magnetic resonance (MR) images. The model is made from an optical-curable resin using 3D computer-aided-format coordinate data taken from 3D MR image-format coordinate data. We have determined the measurement positions on the surface of the model corresponding to a scalp using a 3D magnetic space digitizer and displayed the positions on a 3D MR image of the infant's brain. Using this technique, we then determined the actual 72 measurement positions located over the entire brain surface area for use with our new whole-head probe cap for neonates and infants. This method is useful for evaluating the performance of and designing probe caps.

  2. Three-dimensional visual stimulator

    NASA Astrophysics Data System (ADS)

    Takeda, Tsunehiro; Fukui, Yukio; Hashimoto, Keizo; Hiruma, Nobuyuki

    1995-02-01

    We describe a newly developed three-dimensional visual stimulator (TVS) that can change independently the directions, distances, sizes, luminance, and varieties of two sets of targets for both eyes. It consists of liquid crystal projectors (LCP's) that generate the flexible images of targets, Badal otometers that change target distances without changing the visual angles, and relay-lens systems that change target directions. A special control program is developed for real-time control of six motors and two LCP's in the TVS together with a three-dimensional optometer III that simultaneously measures eye movement, accommodation, pupil diameter, and head movement. distance, 0 to -20 D; direction, 16 horizontally and 15 vertically; size, 0-2 deg visual angle; and luminance, 10-2-10 2 cd/m2. The target images are refreshed at 60 Hz and speeds with which the target makes a smooth change (ramp stimuli) are size, 10 deg/s. A simple application demonstrates the performance.

  3. Metal-chelate dye-controlled organization of Cd32S14(SPh)40(4-) nanoclusters into three-dimensional molecular and covalent open architecture.

    PubMed

    Zheng, Nanfeng; Lu, Haiwei; Bu, Xianhui; Feng, Pingyun

    2006-04-12

    Chalcogenide II-VI nanoclusters are usually prepared as isolated clusters and have defied numerous efforts to join them into covalent open-framework architecture with conventional templating methods such as protonated amines or inorganic cations commonly used to direct the formation of porous frameworks. Herein, we report the first templated synthesis of II-VI covalent superlattices from large II-VI tetrahedral clusters (i.e., [Cd32S14(SPh)38]2-). Our method takes advantage of low charge density of metal-chelate dyes that is a unique match with three-dimensional II-VI semiconductor frameworks in charge density, surface hydrophilicity-hydrophobicity, and spatial organization. In addition, metal-chelate dyes also serve to tune the optical properties of resulting dye semiconductor composite materials.

  4. Three-dimensional water quality model based on FVCOM for total load control management in Guan River Estuary, Northern Jiangsu Province

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Lin, Weibo; Li, Keqiang; Sheng, Jianming; Wei, Aihong; Luo, Feng; Wang, Yan; Wang, Xiulin; Zhang, Longjun

    2016-04-01

    Guan River Estuary and adjacent coastal area (GREC) suffer from serious pollution and eutrophicational problems over the recent years. Thus, reducing the land-based load through the national pollutant total load control program and developing hydrodynamic and water quality models that can simulate the complex circulation and water quality kinetics within the system, including longitudinal and lateral variations in nutrient and COD concentrations, is a matter of urgency. In this study, a three-dimensional, hydrodynamic, water quality model was developed in GREC, Northern Jiangsu Province. The complex three-dimensional hydrodynamics of GREC were modeled using the unstructured-grid, finite-volume, free-surface, primitive equation coastal ocean circulation model (FVCOM). The water quality model was adapted from the mesocosm nutrients dynamic model in the south Yellow Sea and considers eight compartments: dissolved inorganic nitrogen, soluble reactive phosphorus (SRP), phytoplankton, zooplankton, detritus, dissolved organic nitrogen (DON), dissolved organic phosphorus (DOP), and chemical oxygen demand. The hydrodynamic and water quality models were calibrated and confirmed for 2012 and 2013. A comparison of the model simulations with extensive dataset shows that the models accurately simulate the longitudinal distribution of the hydrodynamics and water quality. The model can be used for total load control management to improve water quality in this area.

  5. Three-dimensional, three-vector-component velocimetry of cilia-driven fluid flow using correlation-based approaches in optical coherence tomography

    PubMed Central

    Huang, Brendan K.; Gamm, Ute A.; Bhandari, Vineet; Khokha, Mustafa K.; Choma, Michael A.

    2015-01-01

    Microscale quantification of cilia-driven fluid flow is an emerging area in medical physiology, including pulmonary and central nervous system physiology. Cilia-driven fluid flow is most completely described by a three-dimensional, three-component (3D3C) vector field. Here, we generate 3D3C velocimetry measurements by synthesizing higher dimensional data from lower dimensional measurements obtained using two separate optical coherence tomography (OCT)-based approaches: digital particle image velocimetry (DPIV) and dynamic light scattering (DLS)-OCT. Building on previous work, we first demonstrate directional DLS-OCT for 1D2C velocimetry measurements in the sub-1 mm/s regime (sub-2.5 inch/minute regime) of cilia-driven fluid flow in Xenopus epithelium, an important animal model of the ciliated respiratory tract. We then extend our analysis toward 3D3C measurements in Xenopus using both DLS-OCT and DPIV. We demonstrate the use of DPIV-based approaches towards flow imaging of Xenopus cerebrospinal fluid and mouse trachea, two other important ciliary systems. Both of these flows typically fall in the sub-100 μm/s regime (sub-0.25 inch/minute regime). Lastly, we develop a framework for optimizing the signal-to-noise ratio of 3D3C flow velocity measurements synthesized from 2D2C measures in non-orthogonal planes. In all, 3D3C OCT-based velocimetry has the potential to comprehensively characterize the flow performance of biological ciliated surfaces. PMID:26417520

  6. Comprehensive Three-Dimensional Analysis of the Neuroretinal Rim in Glaucoma Using High-Density Spectral-Domain Optical Coherence Tomography Volume Scans

    PubMed Central

    Tsikata, Edem; Lee, Ramon; Shieh, Eric; Simavli, Huseyin; Que, Christian J.; Guo, Rong; Khoueir, Ziad; de Boer, Johannes; Chen, Teresa C.

    2016-01-01

    Purpose To describe spectral-domain optical coherence tomography (OCT) methods for quantifying neuroretinal rim tissue in glaucoma and to compare these methods to the traditional retinal nerve fiber layer thickness diagnostic parameter. Methods Neuroretinal rim parameters derived from three-dimensional (3D) volume scans were compared with the two-dimensional (2D) Spectralis retinal nerve fiber layer (RNFL) thickness scans for diagnostic capability. This study analyzed one eye per patient of 104 glaucoma patients and 58 healthy subjects. The shortest distances between the cup surface and the OCT-based disc margin were automatically calculated to determine the thickness and area of the minimum distance band (MDB) neuroretinal rim parameter. Traditional 150-μm reference surface–based rim parameters (volume, area, and thickness) were also calculated. The diagnostic capabilities of these five parameters were compared with RNFL thickness using the area under the receiver operating characteristic (AUROC) curves. Results The MDB thickness had significantly higher diagnostic capability than the RNFL thickness in the nasal (0.913 vs. 0.818, P = 0.004) and temporal (0.922 vs. 0.858, P = 0.026) quadrants and the inferonasal (0.950 vs. 0.897, P = 0.011) and superonasal (0.933 vs. 0.868, P = 0.012) sectors. The MDB area and the three neuroretinal rim parameters based on the 150-μm reference surface had diagnostic capabilities similar to RNFL thickness. Conclusions The 3D MDB thickness had a high diagnostic capability for glaucoma and may be of significant clinical utility. It had higher diagnostic capability than the RNFL thickness in the nasal and temporal quadrants and the inferonasal and superonasal sectors. PMID:27768203

  7. Lattice Boltzmann methods applied to large-scale three-dimensional virtual cores constructed from digital optical borehole images of the karst carbonate Biscayne aquifer in southeastern Florida

    USGS Publications Warehouse

    Michael Sukop,; Cunningham, Kevin J.

    2014-01-01

    Digital optical borehole images at approximately 2 mm vertical resolution and borehole caliper data were used to create three-dimensional renderings of the distribution of (1) matrix porosity and (2) vuggy megaporosity for the karst carbonate Biscayne aquifer in southeastern Florida. The renderings based on the borehole data were used as input into Lattice Boltzmann methods to obtain intrinsic permeability estimates for this extremely transmissive aquifer, where traditional aquifer test methods may fail due to very small drawdowns and non-Darcian flow that can reduce apparent hydraulic conductivity. Variogram analysis of the borehole data suggests a nearly isotropic rock structure at lag lengths up to the nominal borehole diameter. A strong correlation between the diameter of the borehole and the presence of vuggy megaporosity in the data set led to a bias in the variogram where the computed horizontal spatial autocorrelation is strong at lag distances greater than the nominal borehole size. Lattice Boltzmann simulation of flow across a 0.4 × 0.4 × 17 m (2.72 m3 volume) parallel-walled column of rendered matrix and vuggy megaporosity indicates a high hydraulic conductivity of 53 m s−1. This value is similar to previous Lattice Boltzmann calculations of hydraulic conductivity in smaller limestone samples of the Biscayne aquifer. The development of simulation methods that reproduce dual-porosity systems with higher resolution and fidelity and that consider flow through horizontally longer renderings could provide improved estimates of the hydraulic conductivity and help to address questions about the importance of scale.

  8. Three-dimensional, three-vector-component velocimetry of cilia-driven fluid flow using correlation-based approaches in optical coherence tomography.

    PubMed

    Huang, Brendan K; Gamm, Ute A; Bhandari, Vineet; Khokha, Mustafa K; Choma, Michael A

    2015-09-01

    Microscale quantification of cilia-driven fluid flow is an emerging area in medical physiology, including pulmonary and central nervous system physiology. Cilia-driven fluid flow is most completely described by a three-dimensional, three-component (3D3C) vector field. Here, we generate 3D3C velocimetry measurements by synthesizing higher dimensional data from lower dimensional measurements obtained using two separate optical coherence tomography (OCT)-based approaches: digital particle image velocimetry (DPIV) and dynamic light scattering (DLS)-OCT. Building on previous work, we first demonstrate directional DLS-OCT for 1D2C velocimetry measurements in the sub-1 mm/s regime (sub-2.5 inch/minute regime) of cilia-driven fluid flow in Xenopus epithelium, an important animal model of the ciliated respiratory tract. We then extend our analysis toward 3D3C measurements in Xenopus using both DLS-OCT and DPIV. We demonstrate the use of DPIV-based approaches towards flow imaging of Xenopus cerebrospinal fluid and mouse trachea, two other important ciliary systems. Both of these flows typically fall in the sub-100 μm/s regime (sub-0.25 inch/minute regime). Lastly, we develop a framework for optimizing the signal-to-noise ratio of 3D3C flow velocity measurements synthesized from 2D2C measures in non-orthogonal planes. In all, 3D3C OCT-based velocimetry has the potential to comprehensively characterize the flow performance of biological ciliated surfaces.

  9. Thermoresponsive nanofabricated substratum for the engineering of three-dimensional tissues with layer-by-layer architectural control.

    PubMed

    Jiao, Alex; Trosper, Nicole E; Yang, Hee Seok; Kim, Jinsung; Tsui, Jonathan H; Frankel, Samuel D; Murry, Charles E; Kim, Deok-Ho

    2014-05-27

    Current tissue engineering methods lack the ability to properly recreate scaffold-free, cell-dense tissues with physiological structures. Recent studies have shown that the use of nanoscale cues allows for precise control over large-area 2D tissue structures without restricting cell growth or cell density. In this study, we developed a simple and versatile platform combining a thermoresponsive nanofabricated substratum (TNFS) incorporating nanotopographical cues and the gel casting method for the fabrication of scaffold-free 3D tissues. Our TNFS allows for the structural control of aligned cell monolayers which can be spontaneously detached via a change in culture temperature. Utilizing our gel casting method, viable, aligned cell sheets can be transferred without loss of anisotropy or stacked with control over individual layer orientations. Transferred cell sheets and individual cell layers within multilayered tissues robustly retain structural anisotropy, allowing for the fabrication of scaffold-free, 3D tissues with hierarchical control of overall tissue structure.

  10. Stability of the human respiratory control system. II. Analysis of a three-dimensional delay state-space model.

    PubMed

    Batzel, J J; Tran, H T

    2000-07-01

    A number of mathematical models of the human respiratory control system have been developed since 1940 to study a wide range of features of this complex system. Among them, periodic breathing (including Cheyne-Stokes respiration and apneustic breathing) is a collection of regular but involuntary breathing patterns that have important medical implications. The hypothesis that periodic breathing is the result of delay in the feedback signals to the respiratory control system has been studied since the work of Grodins et al. in the early 1950's [1]. The purpose of this paper is to study the stability characteristics of a feedback control system of five differential equations with delays in both the state and control variables presented by Khoo et al. [4] in 1991 for modeling human respiration. The paper is divided in two parts. Part I studies a simplified mathematical model of two nonlinear state equations modeling arterial partial pressures of O2 and CO2 and a peripheral controller. Analysis was done on this model to illuminate the effect of delay on the stability. It shows that delay dependent stability is affected by the controller gain, compartmental volumes and the manner in which changes in the ventilation rate is produced (i.e., by deeper breathing or faster breathing). In addition, numerical simulations were performed to validate analytical results. Part II extends the model in Part I to include both peripheral and central controllers. This, however, necessitates the introduction of a third state equation modeling CO2 levels in the brain. In addition to analytical studies on delay dependent stability, it shows that the decreased cardiac output (and hence increased delay) resulting from the congestive heart condition can induce instability at certain control gain levels. These analytical results were also confirmed by numerical simulations. PMID:10958416

  11. Test functions for three-dimensional control-volume mixed finite-element methods on irregular grids

    USGS Publications Warehouse

    Naff, R.L.; Russell, T.F.; Wilson, J.D.; ,; ,; ,; ,; ,

    2000-01-01

    Numerical methods based on unstructured grids, with irregular cells, usually require discrete shape functions to approximate the distribution of quantities across cells. For control-volume mixed finite-element methods, vector shape functions are used to approximate the distribution of velocities across cells and vector test functions are used to minimize the error associated with the numerical approximation scheme. For a logically cubic mesh, the lowest-order shape functions are chosen in a natural way to conserve intercell fluxes that vary linearly in logical space. Vector test functions, while somewhat restricted by the mapping into the logical reference cube, admit a wider class of possibilities. Ideally, an error minimization procedure to select the test function from an acceptable class of candidates would be the best procedure. Lacking such a procedure, we first investigate the effect of possible test functions on the pressure distribution over the control volume; specifically, we look for test functions that allow for the elimination of intermediate pressures on cell faces. From these results, we select three forms for the test function for use in a control-volume mixed method code and subject them to an error analysis for different forms of grid irregularity; errors are reported in terms of the discrete L2 norm of the velocity error. Of these three forms, one appears to produce optimal results for most forms of grid irregularity.

  12. Faulting of rocks in three-dimensional strain fields I. Failure of rocks in polyaxial, servo-control experiments

    USGS Publications Warehouse

    Reches, Z.; Dieterich, J.H.

    1983-01-01

    The dependence of the number of sets of faults and their orientation on the intermediate strain axis is investigated through polyaxial tests, reported here, and theoretical analysis, reported in an accompanying paper. In the experiments, cubic samples of Berea sandstone, Sierra-White and Westerly granites, and Candoro and Solnhofen limestones were loaded on their three pairs of faces by three independent, mutually perpendicular presses at room temperature. Two of the presses were servo-controlled and applied constant displacement rates throughout the experiment. Most samples display three or four sets of faults in orthorhombic symmetry. These faults form in several yielding events that follow a stage of elastic deformation. In many experiments, the maximum and the intermediate compressive stresses interchange orientations during the yielding events, where the corresponding strains are constant. The final stage of most experiments is characterized by slip along the faults. ?? 1983.

  13. Three-dimensional structural control and analysis of hexagonal boron nitride nanosheets assembly in nanocomposite films induced by electric field concentration

    NASA Astrophysics Data System (ADS)

    Fujihara, Takeshi; Cho, Hong-Baek; Kanno, Masanao; Nakayama, Tadachika; Suzuki, Tsuneo; Jiang, Weihua; Suematsu, Hisayuki; Niihara, Koichi

    2014-02-01

    Fabrication and controlled localization of BN nanosheets assemblies were performed in polymer-based nanocomposite films under application of DC electric field switching. The localization of BN nanosheets with linearly assembled structure were modulated by applying a Si-mold electrode with micro-dimensional protrusions on the surface during electric field inducement. The established assembly of BN nanosheets, incorporated in the composite was analyzed three-dimensionally using X-ray computed tomography. The structural variation of linear assembles of BN nanosheets (LABNs) were modulated from filament-like to bridge-like structure by applying switching DC electric field whose effect was further intensified induced by electric field concentration. The nanocomposite films with localized LABNs can be potentially applied for efficient heat dissipation from local heat source, such as modern electronic, optoelectronic, photonic devices, and systems in semiconductor industry.

  14. Controllable Assembly of Vanadium-Containing Polyoxoniobate-Based Three-Dimensional Organic-Inorganic Hybrid Compounds and Their Photocatalytic Properties.

    PubMed

    Hu, Jufang; Wang, Yin; Zhang, Xinning; Chi, Yingnan; Yang, Song; Li, Jikun; Hu, Changwen

    2016-08-01

    The controllable synthesis of two vanadium-containing polyoxoniobate-based three-dimensional organic-inorganic hybrid compounds, [Co(pn)2]4[HPNb10V(IV)2O40(V(IV)O)4]·17H2O (1) and [Co(pn)2]5[PNb12O40(V(IV)O)6](OH)7·15H2O (2), where pn = 1,2-diaminopropane, is realized by changing the hydrothermal temperature or adding N-(aminoethyl)piperazine as an additive. Both compounds 1 and 2 are structurally characterized by single-crystal/powder X-ray diffraction and IR and X-ray photoelectron spectroscopy. Compound 1 features a new divanadium-substituted Keggin polyoxoniobate capped by four vanadyl groups, and the polyanion in 2 exhibits the highest coordination number (10-connected) in polyoxoniobate chemistry. Moreover, the photocatalytic activities of 1 and 2 for hydrogen evolution are preliminarily assessed. PMID:27442602

  15. Taming the degeneration of Bessel beams at an anisotropic-isotropic interface: Toward three-dimensional control of confined vortical waves.

    PubMed

    Riaud, Antoine; Thomas, Jean-Louis; Baudoin, Michael; Bou Matar, Olivier

    2015-12-01

    Despite their self-reconstruction properties in heterogeneous media, Bessel beams are known to degenerate when they are refracted from an isotropic to an anisotropic medium. In this paper, we study the converse situation wherein an anisotropic Bessel beam is refracted into an isotropic medium. It is shown that these anisotropic Bessel beams also degenerate, leading to confined vortical waves that may serve as localized particle trap for acoustical tweezers. The linear nature of this degeneration allows the three-dimensional control of this trap position by wavefront correction. Theory is confronted to experiments performed in the field of acoustics. A swirling surface acoustic wave is synthesized at the surface of a piezoelectric crystal by a microelectromechanical integrated system and radiated inside a miniature liquid vessel. The wavefront correction is operated with inverse filter technique. This work opens perspectives for contactless on-chip manipulation devices.

  16. Taming the degeneration of Bessel beams at an anisotropic-isotropic interface: Toward three-dimensional control of confined vortical waves

    NASA Astrophysics Data System (ADS)

    Riaud, Antoine; Thomas, Jean-Louis; Baudoin, Michael; Bou Matar, Olivier

    2015-12-01

    Despite their self-reconstruction properties in heterogeneous media, Bessel beams are known to degenerate when they are refracted from an isotropic to an anisotropic medium. In this paper, we study the converse situation wherein an anisotropic Bessel beam is refracted into an isotropic medium. It is shown that these anisotropic Bessel beams also degenerate, leading to confined vortical waves that may serve as localized particle trap for acoustical tweezers. The linear nature of this degeneration allows the three-dimensional control of this trap position by wavefront correction. Theory is confronted to experiments performed in the field of acoustics. A swirling surface acoustic wave is synthesized at the surface of a piezoelectric crystal by a microelectromechanical integrated system and radiated inside a miniature liquid vessel. The wavefront correction is operated with inverse filter technique. This work opens perspectives for contactless on-chip manipulation devices.

  17. Control of a three-dimensional magnetic force generated from a magnetic navigation system to precisely manipulate the locomotion of a magnetic microrobot

    NASA Astrophysics Data System (ADS)

    Nam, J. K.; Jeon, S. M.; Lee, W. S.; Jang, G. H.

    2015-05-01

    We propose a method to generate a three-dimensional (3D) magnetic force to manipulate a magnetic microrobot in various environments by using a magnetic navigation system. The proposed method is based on the control of the magnetic force with respect to the change in the magnetization direction of the microrobot and an external magnetic flux gradient. We derived the nonlinear constraint equations which can determine the required direction of the uniform magnetic fields and magnetic gradients to generate the 3D magnetic force of a microrobot. The solutions of the equations were calculated using a geometrical analysis of the equations without any singular point. The proposed methodology was verified on 3D planar environments considering gravitational force, and we also conducted an experiment in a 3D water-filled tubular environment to verify the possibility of the clinical application in human blood vessels.

  18. Three-dimensional conducting oxide nanoarchitectures: morphology-controllable synthesis, characterization, and applications in lithium-ion batteries.

    PubMed

    Liu, Fa-Qian; Wu, Huiming; Li, Tao; Grabstanowicz, Lauren R; Amine, Khalil; Xu, Tao

    2013-07-21

    We report the synthesis, characterization and applications in Li-ion batteries of a set of 3-dimensional (3-D) nanostructured conducting oxides including fluorinated tin oxide (FTO) and aluminum zinc oxide (AZO). The morphology of these 3-D conducting oxide nanoarchitectures can be directed towards either mono-dispersed hollow nanobead matrix or mono-dispersed sponge-like nanoporous matrix by controlling the surface charge of the templating polystyrene (PS) nanobeads, the steric hindrance and hydrolysis rates of the precursors, pH of the solvents etc. during the evaporative co-assembly of the PS beads. These 3-D nanostructured conducting oxide matrices possess high surface area (over 100 m(2) g(-1)) and accessible interconnected pores extending in all three spatial dimensions. By optimizing the temperature profile during calcination, we can obtain large area (of a few cm(2)) and crack-free nanoarchitectured films with thickness over 60 μm. As such, the sheet resistance of these nanoarchitectured films on FTO glass can reach below 20 Ω per square. The nanoarchitectured FTO electrodes were used as anodes in Li-ion batteries, and they showed an enhanced cycling performance and stability over pure SnO2.

  19. Three-dimensional Chiral Plasmonic Oligomers

    NASA Astrophysics Data System (ADS)

    Hentschel, Mario

    2013-03-01

    We demonstrate chiral optical response in stacked arrangements of plasmonic nanostructures. We show that three-dimensional arrangements of plasmonic ``meta-atoms'' only exhibit a chiral optical response if similar plasmonic ``atoms'' are arranged in a handed fashion as we require resonant plasmonic coupling. Moreover, we demonstrate that such particle groupings, similarly to molecular systems, possess the capability to encode their three-dimensional arrangement in unique and well-modulated spectra, making them ideal candidates for a three-dimensional chiral plasmon ruler. Furthermore, we discuss the onset of a broadband chiral optical response in the wavelength regime between 700 nm and 3500 nm upon charge transfer between the nanoparticles. We show in experiment and simulation that this response is due to the ohmic contact between adjacent particles which causes a strong red-shift of the fundamental mode. The geometrical shape of the resulting fused particles allows for efficient excitation of higher order modes. Calculated spectra and field distributions confirm our interpretation and show a number of interacting plasmonic modes. Finally, we will discuss plasmonic diastereomers which consist of multiple chiral centers. We find that the chiral optical response of the composite molecules can be traced back to the properties of the constituting building blocks. We demonstrate that the optical response of complex chiral plasmonic systems can be decomposed and understood in terms of fundamental building blocks, offering simple and straightforward design rules for future applications such as chiral optical elements and enantiomer sensors.

  20. Three-dimensional laser microvision.

    PubMed

    Shimotahira, H; Iizuka, K; Chu, S C; Wah, C; Costen, F; Yoshikuni, Y

    2001-04-10

    A three-dimensional (3-D) optical imaging system offering high resolution in all three dimensions, requiring minimum manipulation and capable of real-time operation, is presented. The system derives its capabilities from use of the superstructure grating laser source in the implementation of a laser step frequency radar for depth information acquisition. A synthetic aperture radar technique was also used to further enhance its lateral resolution as well as extend the depth of focus. High-speed operation was made possible by a dual computer system consisting of a host and a remote microcomputer supported by a dual-channel Small Computer System Interface parallel data transfer system. The system is capable of operating near real time. The 3-D display of a tunneling diode, a microwave integrated circuit, and a see-through image taken by the system operating near real time are included. The depth resolution is 40 mum; lateral resolution with a synthetic aperture approach is a fraction of a micrometer and that without it is approximately 10 mum. PMID:18357177

  1. Three-dimensional display technologies

    PubMed Central

    Geng, Jason

    2014-01-01

    The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain’s power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies. PMID:25530827

  2. Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source

    SciTech Connect

    Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

    2014-09-15

    We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

  3. Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source.

    PubMed

    Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

    2014-09-01

    We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

  4. Three-dimensional radiation transfer modeling in a dicotyledon leaf

    NASA Astrophysics Data System (ADS)

    Govaerts, Yves M.; Jacquemoud, Stéphane; Verstraete, Michel M.; Ustin, Susan L.

    1996-11-01

    The propagation of light in a typical dicotyledon leaf is investigated with a new Monte Carlo ray-tracing model. The three-dimensional internal cellular structure of the various leaf tissues, including the epidermis, the palisade parenchyma, and the spongy mesophyll, is explicitly described. Cells of different tissues are assigned appropriate morphologies and contain realistic amounts of water and chlorophyll. Each cell constituent is characterized by an index of refraction and an absorption coefficient. The objective of this study is to investigate how the internal three-dimensional structure of the tissues and the optical properties of cell constituents control the reflectance and transmittance of the leaf. Model results compare favorably with laboratory observations. The influence of the roughness of the epidermis on the reflection and absorption of light is investigated, and simulation results confirm that convex cells in the epidermis focus light on the palisade parenchyma and increase the absorption of radiation.

  5. Optically detecting the edge-state of a three-dimensional topological insulator under ambient conditions by ultrafast infrared photoluminescence spectroscopy

    PubMed Central

    Maezawa, Shun-ya; Watanabe, Hiroshi; Takeda, Masahiro; Kuroda, Kenta; Someya, Takashi; Matsuda, Iwao; Suemoto, Tohru

    2015-01-01

    Ultrafast infrared photoluminescence spectroscopy was applied to a three-dimensional topological insulator TlBiSe2 under ambient conditions. The dynamics of the luminescence exhibited bulk-insulating and gapless characteristics bounded by the bulk band gap energy. The existence of the topologically protected surface state and the picosecond-order relaxation time of the surface carriers, which was distinguishable from the bulk response, were observed. Our results provide a practical method applicable to topological insulators under ambient conditions for device applications. PMID:26552784

  6. Three-dimensional control-volume distributed multi-point flux approximation coupled with a lower-dimensional surface fracture model

    NASA Astrophysics Data System (ADS)

    Ahmed, Raheel; Edwards, Michael G.; Lamine, Sadok; Huisman, Bastiaan A. H.; Pal, Mayur

    2015-12-01

    A novel cell-centred control-volume distributed multi-point flux approximation (CVD-MPFA) finite-volume formulation is presented for discrete fracture-matrix simulations on unstructured grids in three-dimensions (3D). The grid is aligned with fractures and barriers which are then modelled as lower-dimensional surface interfaces located between the matrix cells in the physical domain. The three-dimensional pressure equation is solved in the matrix domain coupled with a two-dimensional (2D) surface pressure equation solved over fracture networks via a novel surface CVD-MPFA formulation. The CVD-MPFA formulation naturally handles fractures with anisotropic permeabilities on unstructured grids. Matrix-fracture fluxes are expressed in terms of matrix and fracture pressures and define the transfer function, which is added to the lower-dimensional flow equation and couples the three-dimensional and surface systems. An additional transmission condition is used between matrix cells adjacent to low permeable fractures to couple the velocity and pressure jump across the fractures. Convergence and accuracy of the lower-dimensional fracture model is assessed for highly anisotropic fractures having a range of apertures and permeability tensors. A transport equation for tracer flow is coupled via the Darcy flux for single and intersecting fractures. The lower-dimensional approximation for intersecting fractures avoids the more restrictive CFL condition corresponding to the equi-dimensional approximation with explicit time discretisation. Lower-dimensional fracture model results are compared with equi-dimensional model results. Fractures and barriers are efficiently modelled by lower-dimensional interfaces which yield comparable results to those of the equi-dimensional model. Pressure continuity is built into the model across highly conductive fractures, leading to reduced local degrees of freedom in the CVD-MPFA approximation. The formulation is applied to geologically complex

  7. Comparison between three-dimensional and standard miniplates in the management of mandibular angle fractures: a prospective, randomized, double-blind, controlled clinical study.

    PubMed

    Al-Moraissi, E A; Mounair, R M; El-Sharkawy, T M; El-Ghareeb, T I

    2015-03-01

    The aim of this study was to compare the clinical and radiological outcomes of mandibular angle fractures (MAFs) managed with three-dimensional (3D) miniplates and standard miniplates (according to Champy's principles). A prospective, randomized, controlled clinical study was carried out on 20 patients with MAFs, divided into two groups. Group A patients were treated with a single 1-mm 3D titanium miniplate; group B patients were treated with a single 2.0-mm standard titanium miniplate. Patients were followed for 6 months for infection, wound dehiscence, segmental mobility, malocclusion, mouth opening, hardware failure, hardware palpability, paraesthesia, and malunion/non-union. A densitometry analysis was performed using DIGORA software on digital panoramic radiographs to evaluate bone healing. Six complications occurred, representing a total rate of 30%. Three complications occurred in group A and three in group B, with identical complication rates of 30%. No major difference in terms of the radiographic assessment was observed between the two systems. The 3D curved strut plate is an effective treatment modality for the management of MAFs, with a complication rate comparable to that found with the standard miniplate. This trial is registered at ClinicalTrials.gov, number NCT01939015.

  8. Biomechanical aspects of segmented arch mechanics combined with power arm for controlled anterior tooth movement: A three-dimensional finite element study

    PubMed Central

    Ozaki, Hiroya; Tominaga, Jun-ya; Hamanaka, Ryo; Sumi, Mayumi; Chiang, Pao-Chang; Tanaka, Motohiro; Koga, Yoshiyuki

    2015-01-01

    The porpose of this study was to determine the optimal length of power arms for achieving controlled anterior tooth movement in segmented arch mechanics combined with power arm. A three-dimensional finite element method was applied for the simulation of en masse anterior tooth retraction in segmented power arm mechanics. The type of tooth movement, namely, the location of center of rotation of the maxillary central incisor in association with power arm length, was calculated after the retraction force was applied. When a 0.017 × 0.022-in archwire was inserted into the 0.018-in slot bracket, bodily movement was obtained at 9.1 mm length of power arm, namely, at the level of 1.8 mm above the center of resistance. In case a 0.018 × 0.025-in full-size archwire was used, bodily movement of the tooth was produced at the power arm length of 7.0 mm, namely, at the level of 0.3 mm below the center of resistance. Segmented arch mechanics required shorter length of power arms for achieving any type of controlled anterior tooth movement as compared to sliding mechanics. Therefore, this space closing mechanics could be widely applied even for the patients whose gingivobuccal fold is shallow. The segmented arch mechanics combined with power arm could provide higher amount of moment-to-force ratio sufficient for controlled anterior tooth movement without generating friction, and vertical forces when applying retraction force parallel to the occlusal plane. It is, therefore, considered that the segmented power arm mechanics has a simple appliance design and allows more efficient and controllable tooth movement. PMID:25610497

  9. Biomechanical aspects of segmented arch mechanics combined with power arm for controlled anterior tooth movement: A three-dimensional finite element study.

    PubMed

    Ozaki, Hiroya; Tominaga, Jun-Ya; Hamanaka, Ryo; Sumi, Mayumi; Chiang, Pao-Chang; Tanaka, Motohiro; Koga, Yoshiyuki; Yoshida, Noriaki

    2015-01-01

    The porpose of this study was to determine the optimal length of power arms for achieving controlled anterior tooth movement in segmented arch mechanics combined with power arm. A three-dimensional finite element method was applied for the simulation of en masse anterior tooth retraction in segmented power arm mechanics. The type of tooth movement, namely, the location of center of rotation of the maxillary central incisor in association with power arm length, was calculated after the retraction force was applied. When a 0.017 × 0.022-in archwire was inserted into the 0.018-in slot bracket, bodily movement was obtained at 9.1 mm length of power arm, namely, at the level of 1.8 mm above the center of resistance. In case a 0.018 × 0.025-in full-size archwire was used, bodily movement of the tooth was produced at the power arm length of 7.0 mm, namely, at the level of 0.3 mm below the center of resistance. Segmented arch mechanics required shorter length of power arms for achieving any type of controlled anterior tooth movement as compared to sliding mechanics. Therefore, this space closing mechanics could be widely applied even for the patients whose gingivobuccal fold is shallow. The segmented arch mechanics combined with power arm could provide higher amount of moment-to-force ratio sufficient for controlled anterior tooth movement without generating friction, and vertical forces when applying retraction force parallel to the occlusal plane. It is, therefore, considered that the segmented power arm mechanics has a simple appliance design and allows more efficient and controllable tooth movement.

  10. Three-dimensional marginal separation

    NASA Technical Reports Server (NTRS)

    Duck, Peter W.

    1988-01-01

    The three dimensional marginal separation of a boundary layer along a line of symmetry is considered. The key equation governing the displacement function is derived, and found to be a nonlinear integral equation in two space variables. This is solved iteratively using a pseudo-spectral approach, based partly in double Fourier space, and partly in physical space. Qualitatively, the results are similar to previously reported two dimensional results (which are also computed to test the accuracy of the numerical scheme); however quantitatively the three dimensional results are much different.

  11. Effect of hydroxyapatite-containing microspheres embedded into three-dimensional magnesium phosphate scaffolds on the controlled release of lysozyme and in vitro biodegradation

    PubMed Central

    Lee, Jongman; Yun, Hui-suk

    2014-01-01

    The functionality of porous three-dimensional (3D) magnesium phosphate (MgP) scaffold was investigated for the development of a novel protein delivery system and biomimetic bone tissue engineering scaffold. This enhancement can be achieved by incorporation of hydroxyapatite (HA)-containing polymeric microspheres (MSs) into a bulk MgP matrix, and a paste-extruding deposition (PED) system. In this work, the amount of MS and HA was precisely controlled when manufacturing MS-embedded MgP (MS/MgP) composite scaffolds. The main influence was researched in terms of in vitro lysozyme-release, in vitro biodegradation, mechanical properties, and in vitro calcification. The controlled release of lysozyme was indicated, while showing graded release patterns according to HA content. The composite scaffolds degraded gradually with MS content and degradation time. Due to the effect of HA inclusion, the higher HA-containing MS/MgP scaffolds could, not only delay the biodegradation process but also, compensate for the possible loss of mechanical properties. In this regard, it is reasonable to confirm the inverse relationship between biodegradation and corresponding compressive properties. In order to encourage bioactivity and osteoconductivity, the MS/MgP composite scaffolds were subjected to simulated body fluid treatment. Calcium deposition was, in turn, improved with increasing MS and HA content over time. This quantitative result was also proved using morphological and elemental analysis. In summary, a significant transformation of a monolithic MgP scaffold was directed toward a multifunctional bone tissue engineering scaffold equipped with controlled protein delivery, biodegradability, and bioactivity. PMID:25214782

  12. Occlusion-free monocular three-dimensional vision system

    NASA Astrophysics Data System (ADS)

    Theodoracatos, Vassilios E.

    1994-10-01

    This paper describes a new, occlusion-free, monocular three-dimensional vision system. A matrix of light beams (lasers, fiber optics, etc.), substantially parallel to the optic axis of the lens of a video camera, is projected onto a scene. The corresponding coordinates of the perspective image generated on the video-camera sensor, the focal length of the camera lens, and the lateral position of the projected beams of light are used to determine the 'perspective depth' z* of the three-dimensional real image in the space between the lens and the image plane. Direct inverse perspective transformations are used to reconstruct the three- dimensional real-world scene. This system can lead to the development of three-dimensional real-image sensing devices for manufacturing, medical, and defense-related applications. If combined with existing technology, it has high potential for the development of three- dimensional television.

  13. Three dimensional colorimetric assay assemblies

    SciTech Connect

    Charych, D.; Reichart, A.

    2000-06-27

    A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.

  14. The Three-Dimensional Universe.

    ERIC Educational Resources Information Center

    Banks, Dale A.; Powell, Harry D.

    1992-01-01

    Provides instructions for helping students construct a three-dimensional model of a constellation. Aluminum foil spheres with various diameters are used to represent stars with various apparent magnitudes. The positions of the stars in the model are determined from constellation maps and by converting actual star distances into millimeters. (PR)

  15. Three-Dimensional Lissajous Figures.

    ERIC Educational Resources Information Center

    D'Mura, John M.

    1989-01-01

    Described is a mechanically driven device for generating three-dimensional harmonic space figures with different frequencies and phase angles on the X, Y, and Z axes. Discussed are apparatus, viewing stereo pairs, equations of motion, and using space figures in classroom. (YP)

  16. Creating Three-Dimensional Scenes

    ERIC Educational Resources Information Center

    Krumpe, Norm

    2005-01-01

    Persistence of Vision Raytracer (POV-Ray), a free computer program for creating photo-realistic, three-dimensional scenes and a link for Mathematica users interested in generating POV-Ray files from within Mathematica, is discussed. POV-Ray has great potential in secondary mathematics classrooms and helps in strengthening students' visualization…

  17. Three dimensional colorimetric assay assemblies

    DOEpatents

    Charych, Deborah; Reichart, Anke

    2000-01-01

    A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.

  18. Three-dimensional stellarator codes

    PubMed Central

    Garabedian, P. R.

    2002-01-01

    Three-dimensional computer codes have been used to develop quasisymmetric stellarators with modular coils that are promising candidates for a magnetic fusion reactor. The mathematics of plasma confinement raises serious questions about the numerical calculations. Convergence studies have been performed to assess the best configurations. Comparisons with recent data from large stellarator experiments serve to validate the theory. PMID:12140367

  19. Finite Difference Time Domain Analysis of Diffusion Equations with Nonuniform Grids for Time-Resolved Reflectance of an Optical Pulse in Three-Dimensional Scattering Medium

    NASA Astrophysics Data System (ADS)

    Tanifuji, Tadatoshi; Ichitsubo, Khota

    2005-11-01

    An integral form of diffusion equations and their finite difference time domain (FDTD) analysis have been formulated. The analysis is extended to FDTD analysis with nonuniform grids in three-dimensional (3-D) scattering medium. It has been confirmed that 600 time steps in calculation sequences of the time-resolved reflectance for 3-D medium 80 × 80 × 30 mm3 in volume is completed within 4 seconds by utilizing 23 and 43 mm3 nonuniform cubic grids, when a conventional personal computer with 3 GHz CPU clock is used. The conditions for keeping numerical accuracies comparable to those in 23 mm3 uniform grids are made clear. The proposed analysis greatly reduces time to run and memory space in 3-D scattering medium numerical analysis.

  20. Efficient three-dimensional resist profile-driven source mask optimization optical proximity correction based on Abbe-principal component analysis and Sylvester equation

    NASA Astrophysics Data System (ADS)

    Lin, Pei-Chun; Yu, Chun-Chang; Chen, Charlie Chung-Ping

    2015-01-01

    As one of the critical stages of a very large scale integration fabrication process, postexposure bake (PEB) plays a crucial role in determining the final three-dimensional (3-D) profiles and lessening the standing wave effects. However, the full 3-D chemically amplified resist simulation is not widely adopted during the postlayout optimization due to the long run-time and huge memory usage. An efficient simulation method is proposed to simulate the PEB while considering standing wave effects and resolution enhancement techniques, such as source mask optimization and subresolution assist features based on the Sylvester equation and Abbe-principal component analysis method. Simulation results show that our algorithm is 20× faster than the conventional Gaussian convolution method.

  1. A Novel Microfluidic Platform for High-Resolution Imaging of a Three-Dimensional Cell Culture under a Controlled Hypoxic Environment

    PubMed Central

    Funamoto, Kenichi; Zervantonakis, Ioannis K.; Liu, Yuchun; Ochs, Christopher J.; Kim, Choong

    2014-01-01

    Low oxygen tensions experienced in various pathological and physiological conditions are a major stimulus for angiogenesis. Hypoxic conditions play a critical role in regulating cellular behaviour including migration, proliferation and differentiation. This study introduces the use of a microfluidic device that allows for the control of oxygen tension for the study of different three-dimensional (3D) cell cultures for various applications. The device has a central 3D gel region acting as an external cellular matrix, flanked by media channels. On each side, there is a peripheral gas channel through which suitable gas mixtures are supplied to establish a uniform oxygen concentration or gradient within the device. The effects of various parameters, such as gas and media flow rates, device thickness, and diffusion coefficients of oxygen were examined using numerical simulations to determine the characteristics of the microfluidic device. A polycarbonate (PC) film with a low oxygen diffusion coefficient was embedded in the device in proximity above the channels to prevent oxygen diffusion from the incubator environment into the Polydimethylsiloxane (PDMS) device. The oxygen tension in the device was then validated experimentally using a ruthenium-coated (Ru-coated) oxygen-sensing glass cover slip which confirmed the establishment of low uniform oxygen tensions (< 3%) or an oxygen gradient across the gel region. To demonstrate the utility of the microfluidic device for cellular experiments under hypoxic conditions, migratory studies of MDA-MB-231 human breast cancer cells were performed. The microfluidic device allowed for imaging cellular migration with high-resolution, exhibiting an enhanced migration in hypoxia in comparison to normoxia. This microfluidic device presents itself as a promising platform for the investigation of cellular behaviour in a 3D gel scaffold under varying hypoxic conditions. PMID:23023115

  2. Magnetophotonic response of three-dimensional opals.

    PubMed

    Caicedo, José Manuel; Pascu, Oana; López-García, Martín; Canalejas, Víctor; Blanco, Alvaro; López, Cefe; Fontcuberta, Josep; Roig, Anna; Herranz, Gervasi

    2011-04-26

    Three-dimensional magnetophotonic crystals (3D-MPCs) are being postulated as appropriate platforms to tailor the magneto-optical spectral response of magnetic materials and to incorporate this functionality in a new generation of optical devices. By infiltrating self-assembled inverse opal structures with monodisperse nickel nanoparticles we have fabricated 3D-MPCs that show a sizable enhancement of the magneto-optical signal at frequencies around the stop-band edges of the photonic crystals. We have established a proper methodology to disentangle the intrinsic magneto-optical spectra from the nonmagnetic optical activity of the 3D-MPCs. The results of the optical and magneto-optical characterization are consistent with a homogeneous magnetic infiltration of the opal structure that gives rise to both a red-shift of the optical bandgap and a modification of the magneto-optical spectral response due to photonic bandgap effects. The results of our investigation demonstrate the potential of 3D-MPCs fabricated following the approach outlined here and offer opportunities to adapt the magneto-optical spectral response at optical frequencies by appropriate design of the opal structure or magnetic field strength.

  3. Three-dimensional deformation of orthodontic brackets

    PubMed Central

    Melenka, Garrett W; Nobes, David S; Major, Paul W

    2013-01-01

    Braces are used by orthodontists to correct the misalignment of teeth in the mouth. Archwire rotation is a particular procedure used to correct tooth inclination. Wire rotation can result in deformation to the orthodontic brackets, and an orthodontic torque simulator has been designed to examine this wire–bracket interaction. An optical technique has been employed to measure the deformation due to size and geometric constraints of the orthodontic brackets. Images of orthodontic brackets are collected using a stereo microscope and two charge-coupled device cameras, and deformation of orthodontic brackets is measured using a three-dimensional digital image correlation technique. The three-dimensional deformation of orthodontic brackets will be evaluated. The repeatability of the three-dimensional digital image correlation measurement method was evaluated by performing 30 archwire rotation tests using the same bracket and archwire. Finally, five Damon 3MX and five In-Ovation R self-ligating brackets will be compared using this technique to demonstrate the effect of archwire rotation on bracket design. PMID:23762201

  4. Facial three-dimensional morphometry.

    PubMed

    Ferrario, V F; Sforza, C; Poggio, C E; Serrao, G

    1996-01-01

    Three-dimensional facial morphometry was investigated in a sample of 40 men and 40 women, with a new noninvasive computerized method. Subjects ranged in age between 19 and 32 years, had sound dentitions, and no craniocervical disorders. For each subject, 16 cutaneous facial landmarks were automatically collected by a system consisting of two infrared camera coupled device (CCD) cameras, real time hardware for the recognition of markers, and software for the three-dimensional reconstruction of landmarks' x, y, z coordinates. From these landmarks, 15 linear and 10 angular measurements, and four linear distance ratios were computed and averaged for sex. For all angular values, both samples showed a narrow variability and no significant gender differences were demonstrated. Conversely, all the linear measurements were significantly higher in men than in women. The highest intersample variability was observed for the measurements of facial height (prevalent vertical dimension), and the lowest for the measurements of facial depth (prevalent horizontal dimension). The proportions of upper and lower face height relative to the anterior face height showed a significant sex difference. Mean values were in good agreement with literature data collected with traditional methods. The described method allowed the direct and noninvasive calculation of three-dimensional linear and angular measurements that would be usefully applied in clinics as a supplement to the classic x-ray cephalometric analyses. PMID:8540488

  5. Method and apparatus for three dimensional braiding

    NASA Technical Reports Server (NTRS)

    Farley, Gary L. (Inventor)

    1997-01-01

    A machine for three-dimensional braiding of fibers is provided in which carrier members travel on a curved, segmented and movable braiding surface. The carrier members are capable of independent, self-propelled motion along the braiding surface. Carrier member position on the braiding surface is controlled and monitored by computer. Also disclosed is a yarn take-up device capable of maintaining tension in the braiding fiber.

  6. Method and apparatus for three dimensional braiding

    NASA Technical Reports Server (NTRS)

    Farley, Gary L. (Inventor)

    1995-01-01

    A machine for three-dimensional braiding of fibers is provided in which carrier members travel on a curved, segmented and movable braiding surface. The carrier members are capable of independent, self-propelled motion along the braiding surface. Carrier member position on the braiding surface is controlled and monitored by computer. Also disclosed is a yarn take-up device capable of maintaining tension in the braiding fiber.

  7. Three-dimensional motor schema based navigation

    NASA Technical Reports Server (NTRS)

    Arkin, Ronald C.

    1989-01-01

    Reactive schema-based navigation is possible in space domains by extending the methods developed for ground-based navigation found within the Autonomous Robot Architecture (AuRA). Reformulation of two dimensional motor schemas for three dimensional applications is a straightforward process. The manifold advantages of schema-based control persist, including modular development, amenability to distributed processing, and responsiveness to environmental sensing. Simulation results show the feasibility of this methodology for space docking operations in a cluttered work area.

  8. Athermally photoreduced graphene oxides for three-dimensional holographic images

    NASA Astrophysics Data System (ADS)

    Li, Xiangping; Ren, Haoran; Chen, Xi; Liu, Juan; Li, Qin; Li, Chengmingyue; Xue, Gaolei; Jia, Jia; Cao, Liangcai; Sahu, Amit; Hu, Bin; Wang, Yongtian; Jin, Guofan; Gu, Min

    2015-04-01

    The emerging graphene-based material, an atomic layer of aromatic carbon atoms with exceptional electronic and optical properties, has offered unprecedented prospects for developing flat two-dimensional displaying systems. Here, we show that reduced graphene oxide enabled write-once holograms for wide-angle and full-colour three-dimensional images. This is achieved through the discovery of subwavelength-scale multilevel optical index modulation of athermally reduced graphene oxides by a single femtosecond pulsed beam. This new feature allows for static three-dimensional holographic images with a wide viewing angle up to 52 degrees. In addition, the spectrally flat optical index modulation in reduced graphene oxides enables wavelength-multiplexed holograms for full-colour images. The large and polarization-insensitive phase modulation over π in reduced graphene oxide composites enables to restore vectorial wavefronts of polarization discernible images through the vectorial diffraction of a reconstruction beam. Therefore, our technique can be leveraged to achieve compact and versatile holographic components for controlling light.

  9. Athermally photoreduced graphene oxides for three-dimensional holographic images

    PubMed Central

    Li, Xiangping; Ren, Haoran; Chen, Xi; Liu, Juan; Li, Qin; Li, Chengmingyue; Xue, Gaolei; Jia, Jia; Cao, Liangcai; Sahu, Amit; Hu, Bin; Wang, Yongtian; Jin, Guofan; Gu, Min

    2015-01-01

    The emerging graphene-based material, an atomic layer of aromatic carbon atoms with exceptional electronic and optical properties, has offered unprecedented prospects for developing flat two-dimensional displaying systems. Here, we show that reduced graphene oxide enabled write-once holograms for wide-angle and full-colour three-dimensional images. This is achieved through the discovery of subwavelength-scale multilevel optical index modulation of athermally reduced graphene oxides by a single femtosecond pulsed beam. This new feature allows for static three-dimensional holographic images with a wide viewing angle up to 52 degrees. In addition, the spectrally flat optical index modulation in reduced graphene oxides enables wavelength-multiplexed holograms for full-colour images. The large and polarization-insensitive phase modulation over π in reduced graphene oxide composites enables to restore vectorial wavefronts of polarization discernible images through the vectorial diffraction of a reconstruction beam. Therefore, our technique can be leveraged to achieve compact and versatile holographic components for controlling light. PMID:25901676

  10. Dynamic three-dimensional echocardiographic imaging of congenital heart defects in infants and children by computer-controlled tomographic parallel slicing using a single integrated ultrasound instrument.

    PubMed

    Fulton, D R; Marx, G R; Pandian, N G; Romero, B A; Mumm, B; Krauss, M; Wollschläger, H; Ludomirsky, A; Cao, Q L

    1994-03-01

    Three-dimensional cardiac reconstruction generated from transesophageal interrogation can be performed using an integrated unit that captures, processes, and postprocesses tomographic parallel slices of the heart. This probe was used for infants and young children in the transthoracic position to evaluate the feasibility of producing three-dimensional cardiac images with capability for real-time dynamic display. Twenty-two infants and children (range 1 day-3.5 years) underwent image acquisition using a 16 mm 5 MHz 64 element probe placed over the precordium. Two infants were also imaged from the subcostal position. Data was obtained and stored over a single cardiac cycle after acceptable cardiac and respiratory gating intervals were met. The transducer was advanced in 0.5-1 mm increments over the cardiac structures using identical acquisition criteria. The images were reconstructed from the stored digital cubic format and could be oriented in any desired plane. In 9 of the 22 infants the images obtained were of optimal quality. The images obtained displayed normal cardiac structures emphasizing depth relationships as well as visualization of planes not generally demonstrated by two-dimensional imaging. Several lesions were also depicted in a unique fashion using this technique. Though the method employed was limited by movement artifact and reconstruction time, the quality of the three-dimensional display was excellent and enhanced by real-time demonstration. The transthoracic approach was successful in capturing sufficient data to create three-dimensional images, which may have further application in more accurate diagnosis of complex cardiac abnormalities and generation of planes of view which could duplicate surgical visualization of a lesion. Further assessment of the technique in infants with congenital heart disease is warranted. PMID:10146717

  11. Three-dimensional effects on airfoils

    NASA Technical Reports Server (NTRS)

    Chevallier, J. P.

    1983-01-01

    The effects of boundary layer flows along the walls of wind tunnels were studied to validate the transfer of two dimensional calculations to three dimensional transonic flowfield calculations. Results from trials in various wind tunnels were examind to determine the effects of the wall boundary flow on the control surfaces of an airfoil. Models sliding along a groove in the wall of a channel at sub- and transonic speeds were examined, with the finding that with either nonuniformities in the groove, or even if the channel walls are uniform, the lateral boundary layer can cause variations in the central flow region or alter the onset of shock at the transition point. Models for the effects in both turbulence and in the absence of turbulence are formulated, and it is noted that the characteristics of individual wind tunnels must be studied to quantify any existing three dimensional effects.

  12. Reconfigurable, braced, three-dimensional DNA nanostructures

    NASA Astrophysics Data System (ADS)

    Goodman, Russell P.; Heilemann, Mike; Doose, Sören; Erben, Christoph M.; Kapanidis, Achillefs N.; Turberfield, Andrew J.

    2008-02-01

    DNA nanotechnology makes use of the exquisite self-recognition of DNA in order to build on a molecular scale. Although static structures may find applications in structural biology and computer science, many applications in nanomedicine and nanorobotics require the additional capacity for controlled three-dimensional movement. DNA architectures can span three dimensions and DNA devices are capable of movement, but active control of well-defined three-dimensional structures has not been achieved. We demonstrate the operation of reconfigurable DNA tetrahedra whose shapes change precisely and reversibly in response to specific molecular signals. Shape changes are confirmed by gel electrophoresis and by bulk and single-molecule Förster resonance energy transfer measurements. DNA tetrahedra are natural building blocks for three-dimensional construction; they may be synthesized rapidly with high yield of a single stereoisomer, and their triangulated architecture conveys structural stability. The introduction of shape-changing structural modules opens new avenues for the manipulation of matter on the nanometre scale.

  13. Three-dimensional X-ray micro-velocimetry

    PubMed Central

    Lee, Wah-Keat; Fezzaa, Kamel; Uemura, Tomomasa

    2011-01-01

    A direct measurement of three-dimensional X-ray velocimetry with micrometer spatial resolution is presented. The key to this development is the use of a Laue crystal as an X-ray beam splitter and mirror. Three-dimensional flow velocities in a 0.4 mm-diameter tubing were recorded, with <5 µm spatial resolution and speeds of 0.7 mm s−1. This development paves the way for three-dimensional velocimetry in many cases where visible-light techniques are not effective, such as multiphase flow or flow of optically opaque liquids. PMID:21335921

  14. Three dimensional living neural networks

    NASA Astrophysics Data System (ADS)

    Linnenberger, Anna; McLeod, Robert R.; Basta, Tamara; Stowell, Michael H. B.

    2015-08-01

    We investigate holographic optical tweezing combined with step-and-repeat maskless projection micro-stereolithography for fine control of 3D positioning of living cells within a 3D microstructured hydrogel grid. Samples were fabricated using three different cell lines; PC12, NT2/D1 and iPSC. PC12 cells are a rat cell line capable of differentiation into neuron-like cells NT2/D1 cells are a human cell line that exhibit biochemical and developmental properties similar to that of an early embryo and when exposed to retinoic acid the cells differentiate into human neurons useful for studies of human neurological disease. Finally induced pluripotent stem cells (iPSC) were utilized with the goal of future studies of neural networks fabricated from human iPSC derived neurons. Cells are positioned in the monomer solution with holographic optical tweezers at 1064 nm and then are encapsulated by photopolymerization of polyethylene glycol (PEG) hydrogels formed by thiol-ene photo-click chemistry via projection of a 512x512 spatial light modulator (SLM) illuminated at 405 nm. Fabricated samples are incubated in differentiation media such that cells cease to divide and begin to form axons or axon-like structures. By controlling the position of the cells within the encapsulating hydrogel structure the formation of the neural circuits is controlled. The samples fabricated with this system are a useful model for future studies of neural circuit formation, neurological disease, cellular communication, plasticity, and repair mechanisms.

  15. Do growth-stimulated retinal ganglion cell axons find their central targets after optic nerve injury? New insights by three-dimensional imaging of the visual pathway.

    PubMed

    Diekmann, Heike; Leibinger, Marco; Fischer, Dietmar

    2013-10-01

    Retinal ganglion cells (RGCs) do not normally regenerate injured axons. However, several strategies to transform RGCs into a potent regenerative state have been developed in recent years. Intravitreal CNTF application combined with conditional PTEN and SOCS3 deletion or zymosan-induced inflammatory stimulation together with cAMP analogue injection and PTEN-deletion in RGCs induce long-distance regeneration into the optic nerve of adult mice. A recent paper by the Benowitz group (de Lima et al.) claimed that the latter treatment enables full-length regeneration, with axons correctly navigating to their central target zones and partial recovery of visual behaviors. To gain a more detailed view of the extent and the trajectories of regenerating axons, Luo et al. applied a tissue clearing method and fluorescent microscopy to allow the tracing of naïve and regenerating RGC axons in whole ON and all the way to their brain targets. Using this approach, the authors found comparable axon regeneration in the optic nerve after both above-mentioned experimental treatments. Regeneration was accompanied by prevalent aberrant axon growth in the optic nerve and significant axonal misguidance at the optic chiasm. Less than 120 axons per animal reached the optic chiasm and only few entered the correct optic tract. Importantly, no axons reached visual targets in the olivary pretectal nucleus, the lateral geniculate nucleus or the superior colliculus, thereby contradicting and challenging previous claims by the Benowitz group. The data provided by Luo et al. rather suggest that potent stimulation of axonal growth per se is insufficient to achieve functional recovery and underscore the need to investigate regeneration-relevant axon guidance mechanisms in the mature visual system. PMID:23816572

  16. Three-dimensional study of the multi-cavity FEL

    SciTech Connect

    Krishnagopal, S.; Kumar, V.

    1995-12-31

    The Multi-Cavity Free-Electron Laser has been proposed earlier, as a new configuration to obtain short, intense pulses of radiation, the key idea being to pre-bunch the electron beam in a number of very short cavities. Those studies were one-dimensional. Here we use three-dimensional simulations to study the viability of this concept when three-dimensional effects are included, particularly with regard to the transverse modes of the optical beam.

  17. Three-Dimensional Boundary-Layer program (BL3D) for swept subsonic or supersonic wings with application to laminar flow control

    NASA Technical Reports Server (NTRS)

    Iyer, Venkit

    1993-01-01

    The theory, formulation, and solution of three-dimensional, compressible attached laminar flows, applied to swept wings in subsonic or supersonic flow are discussed. Several new features and modifications to an earlier general procedure described in NASA CR 4269, Jan. 1990 are incorporated. Details of interfacing the boundary-layer computation with solution of the inviscid Euler equations are discussed. A description of the computer program, complete with user's manual and example cases, is also included. Comparison of solutions with Navier-Stokes computations with or without boundary-layer suction is given. Output of solution profiles and derivatives required in boundary-layer stability analysis is provided.

  18. Controlling Planar and Vertical Ordering in Three-Dimensional (In,Ga)As Quantum Dot Lattices by GaAs Surface Orientation

    SciTech Connect

    Schmidbauer, M.; Seydmohamadi, Sh.; Wang, Zh.M.; Mazur, Yu.I.; Salamo, G.J.; Grigoriev, D.; Schaefer, P.; Koehler, R.; Hanke, M.

    2006-02-17

    Anisotropic surface diffusion and strain are used to explain the formation of three-dimensional (In,Ga)As quantum dot lattices. The diffusion characteristics of the surface, coupled with the elastic anisotropy of the matrix, provides an excellent opportunity to influence the dot positions. In particular, quantum dots that are laterally organized into long chains or chessboard two-dimensional arrays vertically organized with strict vertical ordering or vertical ordering that is inclined to the sample surface normal are accurately predicted and observed.

  19. Three-dimensional infrared metamaterial with asymmetric transmission

    DOE PAGES

    Kenanakis, George; Xomalis, Aggelos; Selimis, Alexandros; Vamvakaki, Maria; Farsari, Maria; Kafesaki, Maria; Soukoulis, Costas M.; Economou, Eleftherios N.

    2015-01-14

    A novel three-dimensional (3D) metallic metamaterial structure with asymmetric transmission for linear polarization is demonstrated in the infrared spectral region. The structure was fabricated by direct laser writing and selective electroless silver coating, a straightforward, novel technique producing mechanically and chemically stable 3D photonic structures. The structure unit cell is composed of a pair of conductively coupled magnetic resonators, and the asymmetric transmission response results from interplay of electric and magnetic responses; this equips the structure with almost total opaqueness along one propagation direction versus satisfying transparency along the opposite one. It also offers easily adjustable impedance, 90° one-way puremore » optical activity and backward propagation possibility, resulting thus in unique capabilities in polarization control and isolation applications. We show also that scaling down the structure can make it capable of exhibiting its asymmetric transmission and its polarization capabilities in the optical region.« less

  20. Three-dimensional infrared metamaterial with asymmetric transmission

    SciTech Connect

    Kenanakis, George; Xomalis, Aggelos; Selimis, Alexandros; Vamvakaki, Maria; Farsari, Maria; Kafesaki, Maria; Soukoulis, Costas M.; Economou, Eleftherios N.

    2015-01-14

    A novel three-dimensional (3D) metallic metamaterial structure with asymmetric transmission for linear polarization is demonstrated in the infrared spectral region. The structure was fabricated by direct laser writing and selective electroless silver coating, a straightforward, novel technique producing mechanically and chemically stable 3D photonic structures. The structure unit cell is composed of a pair of conductively coupled magnetic resonators, and the asymmetric transmission response results from interplay of electric and magnetic responses; this equips the structure with almost total opaqueness along one propagation direction versus satisfying transparency along the opposite one. It also offers easily adjustable impedance, 90° one-way pure optical activity and backward propagation possibility, resulting thus in unique capabilities in polarization control and isolation applications. We show also that scaling down the structure can make it capable of exhibiting its asymmetric transmission and its polarization capabilities in the optical region.

  1. Three-dimensional reconstruction in free-space whole-body fluorescence tomography of mice using optically reconstructed surface and atlas anatomy

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaofeng; Badea, Cristian T.; Johnson, G. Allan

    2009-11-01

    We present a 3-D image reconstruction method for free-space fluorescence tomography of mice using hybrid anatomical prior information. Specifically, we use an optically reconstructed surface of the experimental animal and a digital mouse atlas to approximate the anatomy of the animal as structural priors to assist image reconstruction. Experiments are carried out on a cadaver of a nude mouse with a fluorescent inclusion (2.4-mm-diam cylinder) implanted in the chest cavity. Tomographic fluorescence images are reconstructed using an iterative algorithm based on a finite element method. Coregistration of the fluorescence reconstruction and micro-CT (computed tomography) data acquired afterward show good localization accuracy (localization error 1.2+/-0.6 mm). Using the optically reconstructed surface, but without the atlas anatomy, image reconstruction fails to show the fluorescent inclusion correctly. The method demonstrates the utility of anatomical priors in support of free-space fluorescence tomography.

  2. Multiphoton excitation microscopy of in vivo human skin. Functional and morphological optical biopsy based on three-dimensional imaging, lifetime measurements and fluorescence spectroscopy.

    PubMed

    Masters, B R; So, P T; Gratton, E

    1998-02-01

    Two-photon excitation microscopy has the potential as an effective, noninvasive, diagnostic tool for in vivo examination of human deep tissue structure at the subcellular level. By using infrared photons as the excitation source in two-photon microscopy, a significant improvement in penetration depth can be achieved because of the much lower tissue scattering and absorption coefficients in the infrared wavelengths. Two-photon absorption occurs primarily at the focal point and provides the physical basis for optical sectioning. Multiphoton excitation microscopy at 730 nm was used to image in vivo human skin autofluorescence from the surface to a depth of about 200 microns. The spectroscopic data suggest that reduced pyridine nucleotides, NAD(P)H, are the primary source of the skin autofluorescence using 730 nm excitation. This study demonstrates the use of multiphoton excitation microscopy for functional imaging of the metabolic states of in vivo human skin cells and provides a functional and morphological optical biopsy.

  3. Three-dimensional reconstruction in free-space whole-body fluorescence tomography of mice using optically reconstructed surface and atlas anatomy

    PubMed Central

    Zhang, Xiaofeng; Badea, Cristian T.; Johnson, G. Allan

    2009-01-01

    We present a 3-D image reconstruction method for free-space fluorescence tomography of mice using hybrid anatomical prior information. Specifically, we use an optically reconstructed surface of the experimental animal and a digital mouse atlas to approximate the anatomy of the animal as structural priors to assist image reconstruction. Experiments are carried out on a cadaver of a nude mouse with a fluorescent inclusion (2.4-mm-diam cylinder) implanted in the chest cavity. Tomographic fluorescence images are reconstructed using an iterative algorithm based on a finite element method. Coregistration of the fluorescence reconstruction and micro-CT (computed tomography) data acquired afterward show good localization accuracy (localization error 1.2±0.6 mm). Using the optically reconstructed surface, but without the atlas anatomy, image reconstruction fails to show the fluorescent inclusion correctly. The method demonstrates the utility of anatomical priors in support of free-space fluorescence tomography. PMID:20059248

  4. Implementation of a parallel-beam optical-CT apparatus for three-dimensional radiation dosimetry using a high-resolution CCD camera

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Tzeng; Chen, Chin-Hsing; Hung, Chao-Nan; Tuan, Chiu-Ching; Chang, Yuan-Jen

    2015-06-01

    In this study, a charge-coupled device (CCD) camera with 2-megapixel (1920×1080-pixel) and 12-bit resolution was developed for optical computed tomography(optical CT). The signal-to-noise ratio (SNR) of our system was 30.12 dB, better than that of commercially available CCD cameras (25.31 dB). The 50% modulation transfer function (MTF50) of our 1920×1080-pixel camera gave a line width per picture height (LW/PH) of 745, which is 73% of the diffraction-limited resolution. Compared with a commercially available 1-megapixel CCD camera (1296×966-pixel) with a LW/PH=358 and 46.6% of the diffraction-limited resolution, our camera system provided higher spatial resolution and better image quality. The NIPAM gel dosimeter was used to evaluate the optical CT with a 2-megapixel CCD. A clinical five-field irradiation treatment plan was generated using the Eclipse planning system (Varian Corp., Palo Alto, CA, USA). The gel phantom was irradiated using a 6-MV Varian Clinac IX linear accelerator (Varian). The measured NIPAM gel dose distributions and the calculated dose distributions, generated by the treatment planning software (TPS), were compared using the 3% dose-difference and 3 mm distance-to-agreement criteria. The gamma pass rate was as high as 98.2% when 2-megapixel CCD camera was used in optical CT. However, the gamma pass rate was only 96.0% when a commercially available 1-megapixel CCD camera was used.

  5. Three-dimensional coil inductor

    DOEpatents

    Bernhardt, Anthony F.; Malba, Vincent

    2002-01-01

    A three-dimensional coil inductor is disclosed. The inductor includes a substrate; a set of lower electrically conductive traces positioned on the substrate; a core placed over the lower traces; a set of side electrically conductive traces laid on the core and the lower traces; and a set of upper electrically conductive traces attached to the side traces so as to form the inductor. Fabrication of the inductor includes the steps of forming a set of lower traces on a substrate; positioning a core over the lower traces; forming a set of side traces on the core; connecting the side traces to the lower traces; forming a set of upper traces on the core; and connecting the upper traces to the side traces so as to form a coil structure.

  6. Three-dimensional aromatic networks.

    PubMed

    Toyota, Shinji; Iwanaga, Tetsuo

    2014-01-01

    Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

  7. Three-dimensional reconstruction of specular reflecting technical surfaces using structured light microscopy

    NASA Astrophysics Data System (ADS)

    Kettel, Johannes; Müller, Claas; Reinecke, Holger

    2014-11-01

    In computer assisted quality control the three-dimensional reconstruction of technical surfaces is playing an ever more important role. Due to the demand on high measurement accuracy and data acquisition rates, structured light optical microscopy has become a valuable solution for the three-dimensional measurement of technical surfaces with high vertical and lateral resolution. However, the three-dimensional reconstruction of specular reflecting technical surfaces with very low surface-roughness and local slopes still remains a challenge to optical measurement principles. Furthermore the high data acquisition rates of current optical measurement systems depend on highly complex and expensive scanning-techniques making them impractical for inline quality control. In this paper we present a novel measurement principle based on a multi-pinhole structured light solution without moving parts which enables the threedimensional reconstruction of specular and diffuse reflecting technical surfaces. This measurement principle is based on multiple and parallel processed point-measurements. These point measurements are realized by spatially locating and analyzing the resulting Point Spread Function (PSF) in parallel for each point measurement. Analysis of the PSF is realized by pattern recognition and model-fitting algorithms accelerated by current Graphics-Processing-Unit (GPU) hardware to reach suitable measurement rates. Using the example of optical surfaces with very low surface-roughness we demonstrate the three-dimensional reconstruction of these surfaces by applying our measurement principle. Thereby we show that the resulting high measurement accuracy enables cost-efficient three-dimensional surface reconstruction suitable for inline quality control.

  8. Three-dimensional optofluidic device for isolating microbes

    NASA Astrophysics Data System (ADS)

    Keloth, A.; Paterson, L.; Markx, G. H.; Kar, A. K.

    2015-03-01

    Development of efficient methods for isolation and manipulation of microorganisms is essential to study unidentified and yet-to-be cultured microbes originating from a variety of environments. The discovery of novel microbes and their products have the potential to contribute to the development of new medicines and other industrially important bioactive compounds. In this paper we describe the design, fabrication and validation of an optofluidic device capable of redirecting microbes within a flow using optical forces. The device holds promise to enable the high throughput isolation of single microbes for downstream culture and analysis. Optofluidic devices are widely used in clinical research, cell biology and biomedical engineering as they are capable of performing analytical functions such as controlled transportation, compact and rapid processing of nanolitres to millilitres of clinical or biological samples. We have designed and fabricated a three dimensional optofluidic device to control and manipulate microorganisms within a microfluidic channel. The device was fabricated in fused silica by ultrafast laser inscription (ULI) followed by selective chemical etching. The unique three-dimensional capability of ULI is utilized to integrate microfluidic channels and waveguides within the same substrate. The main microfluidic channel in the device constitutes the path of the sample. Optical waveguides are fabricated at right angles to the main microfluidic channel. The potential of the optical scattering force to control and manipulate microorganisms is discussed in this paper. A 980 nm continuous wave (CW) laser source, coupled to the waveguide, is used to exert radiation pressure on the particle and particle migrations at different flow velocities are recorded. As a first demonstration, device functionality is validated using fluorescent microbeads and initial trials with microalgae are presented.

  9. Three-dimensional Fourier domain optical coherence tomography in vivo imaging of alveolar tissue in the intact thorax using the parietal pleura as a window

    NASA Astrophysics Data System (ADS)

    Meissner, Sven; Knels, Lilla; Schnabel, Christian; Koch, Thea; Koch, Edmund

    2010-01-01

    In vivo determination of 3-D and dynamic geometries of alveolar structures with adequate resolution is essential for developing numerical models of the lung. A thorax window is prepared in anesthetized rabbits by removal of muscle tissue between the third and fourth rib without harming the parietal pleura. The transparent parietal pleura allows contact-free imaging by intravital microscopy (IVM) and 3-D optical coherence tomography (3-D OCT). We demonstrate that dislocation of the lung surface is small enough to observe identical regions in the expiratory and inspiratory plateau phase, and that OCT in this animal model is suitable for generating 3-D geometry of in vivo lung parenchyma. To our knowledge, we present a novel thorax window preparation technique for 3-D imaging of alveolar dynamics for the first time. The 3-D datasets of the fine structure of the lung beneath the pleura could provide a basis for the development of 3-D numerical models of the lung.

  10. In-lab three-dimensional printing

    PubMed Central

    Partridge, Roland; Conlisk, Noel; Davies, Jamie A.

    2012-01-01

    The development of the microscope in 1590 by Zacharias Janssenby and Hans Lippershey gave the world a new way of visualizing details of morphogenesis and development. More recent improvements in this technology including confocal microscopy, scanning electron microscopy (SEM) and optical projection tomography (OPT) have enhanced the quality of the resultant image. These technologies also allow a representation to be made of a developing tissue’s three-dimensional (3-D) form. With all these techniques however, the image is delivered on a flat two-dimensional (2-D) screen. 3-D printing represents an exciting potential to reproduce the image not simply on a flat screen, but in a physical, palpable three-dimensional structure. Here we explore the scope that this holds for exploring and interacting with the structure of a developing organ in an entirely novel way. As well as being useful for visualization, 3-D printers are capable of rapidly and cost-effectively producing custom-made structures for use within the laboratory. We here describe the advantages of producing hardware for a tissue culture system using an inexpensive in-lab printer. PMID:22652907

  11. Three-dimensional reconstructions of solid surfaces using conventional microscopes.

    PubMed

    Ficker, Tomáš; Martišek, Dalibor

    2016-01-01

    The three-dimensional digital replicas of solid surfaces are subject of interest of different branches of science and technology. The present paper in its introductory parts brings an overview of the various microscopic reconstructive techniques based on optical sectioning. The main attention is devoted to conventional reconstruction methods and especially to that one employing the Fourier transform. The three-dimensional replicas of this special reconstructive frequency method are compared graphically and numerically with the three-dimensional replicas of the confocal method. Based on the comparative study it has been concluded that the quality of the conventional replicas of surfaces possessing textures of intermediate height irregularities is acceptable and almost comparable with the quality of confocal replicas. This study is relevant both for identifying a convenient technique that provides good qualities of three-dimensional replicas and for selecting the hardware whose price is affordable even for small research groups studying rougher surface textures.

  12. Three-dimensional reconstructions of solid surfaces using conventional microscopes.

    PubMed

    Ficker, Tomáš; Martišek, Dalibor

    2016-01-01

    The three-dimensional digital replicas of solid surfaces are subject of interest of different branches of science and technology. The present paper in its introductory parts brings an overview of the various microscopic reconstructive techniques based on optical sectioning. The main attention is devoted to conventional reconstruction methods and especially to that one employing the Fourier transform. The three-dimensional replicas of this special reconstructive frequency method are compared graphically and numerically with the three-dimensional replicas of the confocal method. Based on the comparative study it has been concluded that the quality of the conventional replicas of surfaces possessing textures of intermediate height irregularities is acceptable and almost comparable with the quality of confocal replicas. This study is relevant both for identifying a convenient technique that provides good qualities of three-dimensional replicas and for selecting the hardware whose price is affordable even for small research groups studying rougher surface textures. PMID:26381761

  13. Three-dimensional plasmonic stereoscopic prints in full colour

    NASA Astrophysics Data System (ADS)

    Goh, Xiao Ming; Zheng, Yihan; Tan, Shawn J.; Zhang, Lei; Kumar, Karthik; Qiu, Cheng-Wei; Yang, Joel K. W.

    2014-11-01

    Metal nanostructures can be designed to scatter different colours depending on the polarization of the incident light. Such spectral control is attractive for applications such as high-density optical storage, but challenges remain in creating microprints with a single-layer architecture that simultaneously enables full-spectral and polarization control of the scattered light. Here we demonstrate independently tunable biaxial colour pixels composed of isolated nanoellipses or nanosquare dimers that can exhibit a full range of colours in reflection mode with linear polarization dependence. Effective polarization-sensitive full-colour prints are realized. With this, we encoded two colour images within the same area and further use this to achieve depth perception by realizing three-dimensional stereoscopic colour microprint. Coupled with the low cost and durability of aluminium as the functional material in our pixel design, such polarization-sensitive encoding can realize a wide spectrum of applications in colour displays, data storage and anti-counterfeiting technologies.

  14. Three-dimensional plasmonic stereoscopic prints in full colour.

    PubMed

    Goh, Xiao Ming; Zheng, Yihan; Tan, Shawn J; Zhang, Lei; Kumar, Karthik; Qiu, Cheng-Wei; Yang, Joel K W

    2014-11-04

    Metal nanostructures can be designed to scatter different colours depending on the polarization of the incident light. Such spectral control is attractive for applications such as high-density optical storage, but challenges remain in creating microprints with a single-layer architecture that simultaneously enables full-spectral and polarization control of the scattered light. Here we demonstrate independently tunable biaxial colour pixels composed of isolated nanoellipses or nanosquare dimers that can exhibit a full range of colours in reflection mode with linear polarization dependence. Effective polarization-sensitive full-colour prints are realized. With this, we encoded two colour images within the same area and further use this to achieve depth perception by realizing three-dimensional stereoscopic colour microprint. Coupled with the low cost and durability of aluminium as the functional material in our pixel design, such polarization-sensitive encoding can realize a wide spectrum of applications in colour displays, data storage and anti-counterfeiting technologies.

  15. Advanced Three-Dimensional Display System

    NASA Technical Reports Server (NTRS)

    Geng, Jason

    2005-01-01

    A desktop-scale, computer-controlled display system, initially developed for NASA and now known as the VolumeViewer(TradeMark), generates three-dimensional (3D) images of 3D objects in a display volume. This system differs fundamentally from stereoscopic and holographic display systems: The images generated by this system are truly 3D in that they can be viewed from almost any angle, without the aid of special eyeglasses. It is possible to walk around the system while gazing at its display volume to see a displayed object from a changing perspective, and multiple observers standing at different positions around the display can view the object simultaneously from their individual perspectives, as though the displayed object were a real 3D object. At the time of writing this article, only partial information on the design and principle of operation of the system was available. It is known that the system includes a high-speed, silicon-backplane, ferroelectric-liquid-crystal spatial light modulator (SLM), multiple high-power lasers for projecting images in multiple colors, a rotating helix that serves as a moving screen for displaying voxels [volume cells or volume elements, in analogy to pixels (picture cells or picture elements) in two-dimensional (2D) images], and a host computer. The rotating helix and its motor drive are the only moving parts. Under control by the host computer, a stream of 2D image patterns is generated on the SLM and projected through optics onto the surface of the rotating helix. The system utilizes a parallel pixel/voxel-addressing scheme: All the pixels of the 2D pattern on the SLM are addressed simultaneously by laser beams. This parallel addressing scheme overcomes the difficulty of achieving both high resolution and a high frame rate in a raster scanning or serial addressing scheme. It has been reported that the structure of the system is simple and easy to build, that the optical design and alignment are not difficult, and that the

  16. Three-dimensional nonlinear optical chromophores based on metal-to-ligand charge-transfer from ruthenium(II) or iron(II) centers.

    PubMed

    Coe, Benjamin J; Harris, James A; Brunschwig, Bruce S; Asselberghs, Inge; Clays, Koen; Garín, Javier; Orduna, Jesús

    2005-09-28

    In this article, we describe a series of new complex salts in which electron-rich transition-metal centers are coordinated to three electron-accepting N-methyl/aryl-2,2':4,4' ':4',4' ''-quaterpyridinium ligands. These complexes contain either Ru(II) or Fe(II) ions and have been characterized by using various techniques, including electronic absorption spectroscopy and cyclic voltammetry. Molecular quadratic nonlinear optical (NLO) responses beta have been determined by using hyper-Rayleigh scattering at 800 nm and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d --> pi* metal-to-ligand charge-transfer bands. The latter experiments reveal that these putatively octupolar D(3) chromophores exhibit two substantial components of the beta tensor which are associated with transitions to dipolar excited states. Computations involving time-dependent density-functional theory and the finite field method serve to further illuminate the electronic structures and associated linear and NLO properties of the new chromophoric salts. PMID:16173774

  17. In vivo three-dimensional imaging of normal tissue and tumors in the rabbit pleural cavity using endoscopic swept source optical coherence tomography with thoracoscopic guidance

    NASA Astrophysics Data System (ADS)

    Xie, Tuqiang; Liu, Gangjun; Kreuter, Kelly; Mahon, Sari; Colt, Henri; Mukai, David; Peavy, George M.; Chen, Zhongping; Brenner, Matthew

    2009-11-01

    The purpose of this study was to develop a dynamic tunable focal distance graded-refractive-index lens rod-based high-speed 3-D swept-source (SS) optical coherence tomography (OCT) endoscopic system and demonstrate real-time in vivo, high-resolution (10-μm) imaging of pleural-based malignancies in an animal model. The GRIN lens-based 3-D SS OCT system, which images at 39 fps with 512 A-lines per frame, was able to capture images of and detect abnormalities during thoracoscopy in the thoracic cavity, including the pleura, chest wall, pericardium, and the lungs. The abnormalities were confirmed by histological evaluation and compared to OCT findings. The dynamic tunable focal distance range and rapid speed of the probe and SS prototype OCT system enabled this first-reported application of in vivo 3-D thoracoscopic imaging of pleural-based malignancies. The imaging probe of the system was found to be easily adaptable to various sites within the thoracic cavity and can be readily adapted to other sites, including rigid airway endoscopic examinations.

  18. Three-dimensional integration of passive and active polymer waveguide devices

    NASA Astrophysics Data System (ADS)

    Garner, Sean Matthew

    This thesis presents the design, fabrication, and experimental results of three dimensionally integrated optics. This vertical and horizontal integration of polymer waveguide structures increases the integration density, reduces interconnection routing difficulties, and expands the functional diversity of adjacent devices. The devices discussed depend on the fabrication of vertical slopes using unconventional photolithography and reactive ion etching techniques. The slopes produced allow fully functional three dimensionally integrated optics that incorporate both passive and active waveguide elements. Passive structures such as vertical waveguide bends, power splitters, and polarization splitters enable three dimensional routing of the optical power among multiple vertical levels. Single mode vertical waveguide bends are demonstrated with polarization insensitive excess losses of 0.2dB. These waveguide structures incorporated bending angles up to 1.5°. Three dimensional 1 x 4 splitters, possess excess losses of 0.5dB and show the ability to fabricate complex waveguide structures in both the horizontal and vertical directions. These vertical power splitters showed controllable power splitting ratios in the output waveguides by controlling the spin cast film thickness within 0.5μM and the slope angle within 0.5°. The vertical polarization splitters incorporated birefringent polymer materials to create an adiabatic mode splitter. These possessed power extinction ratios of about 15dB for both input polarizations. The passive structures of vertical waveguide bends, power splitters, and polarization splitters enable practical three dimensional integrated optics by providing vertical routing capability of the optical signal analogous to those typically found in conventional two dimensional waveguide interconnects. Three dimensionally integrated active devices such as low-loss hybrid modulators and vertically integrated modulator designs create fully functional

  19. Automatic three-dimensional registration of intra-vascular optical coherence tomography images for the clinical evaluation of stent implantation over time

    NASA Astrophysics Data System (ADS)

    Ughi, Giovanni J.; Adriaenssens, Tom; Larsson, Matilda; Dubois, Christophe; Sinnaeve, Peter; Coosemans, Mark; Desmet, Walter; D'hooghe, Jan

    2012-01-01

    In the last decade a large number of new intracoronary devices (i.e. drug-eluting stents, DES) have been developed to reduce the risks related to bare metal stent (BMS) implantation. The use of this new generation of DES has been shown to substantially reduce, compared with BMS, the occurrence of restenosis and recurrent ischemia that would necessitate a second revascularization procedure. Nevertheless, safety issues on the use of DES persist and full understanding of mechanisms of adverse clinical events is still a matter of concern and debate. Intravascular Optical Coherence Tomography (IV-OCT) is an imaging technique able to visualize the microstructure of blood vessels with an axial resolution <20 μm. Due to its very high spatial resolution, it enables detailed in-vivo assessment of implanted devices and vessel wall. Currently, the aim of several major clinical trials is to observe and quantify the vessel response to DES implantation over time. However, image analysis is currently performed manually and corresponding images, belonging to different IV-OCT acquisitions, can only be matched through a very labor intensive and subjective procedure. The aim of this study is to develop and validate a new methodology for the automatic registration of IV-OCT datasets on an image level. Hereto, we propose a landmark based rigid registration method exploiting the metallic stent framework as a feature. Such a tool would provide a better understanding of the behavior of different intracoronary devices in-vivo, giving unique insights about vessel pathophysiology and performance of new generation of intracoronary devices and different drugs.

  20. Dynamic Three-Dimensional Echocardiography

    NASA Astrophysics Data System (ADS)

    Matsusaka, Katsuhiko; Doi, Motonori; Oshiro, Osamu; Chihara, Kunihiro

    2000-08-01

    Conventional three-dimensional (3D) ultrasound imaging equipment for diagnosis requires much time to reconstruct 3D images or fix the view point for observing the 3D image. Thus, it is inconvenient for cardiac diagnosis. In this paper, we propose a new dynamic 3D echocardiography system. The system produces 3D images in real-time and permits changes in view point. This system consists of ultrasound diagnostic equipment, a digitizer and a computer. B-mode images are projected to a virtual 3D space by referring to the position of the probe of the ultrasound diagnosis equipment. The position is obtained by the digitizer to which the ultrasound probe is attached. The 3D cardiac image is constructed from B-mode images obtained simultaneously in the cardiac cycle. To obtain the same moment of heartbeat in the cardiac cycle, this system uses the electrocardiography derived from the diagnosis equipment. The 3D images, which show various scenes of the stage of heartbeat action, are displayed sequentially. The doctor can observe 3D images cut in any plane by pushing a button of the digitizer and zooming with the keyboard. We evaluated our prototype system by observation of a mitral valve in motion.

  1. Three dimensional magnetic abacus memory

    NASA Astrophysics Data System (ADS)

    Zhang, Shilei; Zhang, Jingyan; Baker, Alexander A.; Wang, Shouguo; Yu, Guanghua; Hesjedal, Thorsten

    2014-08-01

    Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme. It is inspired by the idea of second quantisation, dealing with the memory state of the entire stack simultaneously. Direct read operations are implemented by measuring the artificially engineered `quantised' Hall voltage, each representing a count of the spin-up and spin-down layers in the stack. This new memory system further allows for both flexible scaling of the system and fast communication among cells. The magnetic abacus provides a promising approach for future nonvolatile 3D magnetic random access memory.

  2. Three dimensional magnetic abacus memory.

    PubMed

    Zhang, ShiLei; Zhang, JingYan; Baker, Alexander A; Wang, ShouGuo; Yu, GuangHua; Hesjedal, Thorsten

    2014-08-22

    Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme. It is inspired by the idea of second quantisation, dealing with the memory state of the entire stack simultaneously. Direct read operations are implemented by measuring the artificially engineered 'quantised' Hall voltage, each representing a count of the spin-up and spin-down layers in the stack. This new memory system further allows for both flexible scaling of the system and fast communication among cells. The magnetic abacus provides a promising approach for future nonvolatile 3D magnetic random access memory.

  3. Three dimensional magnetic abacus memory

    NASA Astrophysics Data System (ADS)

    Zhang, Shilei; Zhang, Jingyan; Baker, Alexander; Wang, Shouguo; Yu, Guanghua; Hesjedal, Thorsten

    2015-03-01

    Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the individual data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme which envisages a classical abacus with the beads operated by electron spins. It is inspired by the idea of second quantization, dealing with the memory state of the entire stack simultaneously. Direct read operations are implemented by measuring the artificially engineered `quantized' Hall voltage, representing a count of the spin-up and spin-down layers in the stack. This concept of `second quantization of memory' realizes the 3D memory architecture with superior reading and operation efficiency, thus is a promising approach for future nonvolatile magnetic random access memory.

  4. True three-dimensional camera

    NASA Astrophysics Data System (ADS)

    Kornreich, Philipp; Farell, Bart

    2013-01-01

    An imager that can measure the distance from each pixel to the point on the object that is in focus at the pixel is described. This is accomplished by short photo-conducting lightguides at each pixel. In the eye the rods and cones are the fiber-like lightguides. The device uses ambient light that is only coherent in spherical shell-shaped light packets of thickness of one coherence length. Modern semiconductor technology permits the construction of lightguides shorter than a coherence length of ambient light. Each of the frequency components of the broad band light arriving at a pixel has a phase proportional to the distance from an object point to its image pixel. Light frequency components in the packet arriving at a pixel through a convex lens add constructively only if the light comes from the object point in focus at this pixel. The light in packets from all other object points cancels. Thus the pixel receives light from one object point only. The lightguide has contacts along its length. The lightguide charge carriers are generated by the light patterns. These light patterns, and thus the photocurrent, shift in response to the phase of the input signal. Thus, the photocurrent is a function of the distance from the pixel to its object point. Applications include autonomous vehicle navigation and robotic vision. Another application is a crude teleportation system consisting of a camera and a three-dimensional printer at a remote location.

  5. Three-Dimensional Schlieren Measurements

    NASA Astrophysics Data System (ADS)

    Sutherland, Bruce; Cochrane, Andrea

    2004-11-01

    Schlieren systems visualise disturbances that change the index of refraction of a fluid, for example due to temperature or salinity disturbances. `Synthetic schlieren' refers to a recent advance in which these disturbances are visualised with a digital camera and image-processing technology rather than the classical use of parabolic mirrors and a knife-edge. In a typical setup, light from an image of horizontal lines or dots passes almost horizontally through the test section of a fluid to a CCD camera. Refractive index disturbances distort the image and digital comparison of successive images reveals the plan-form structure and time evolution of the disturbances. If the disturbance is effectively two-dimensional, meaning that it is uniform across the line-of-sight of the camera, then its magnitude as well as its structure can measured through simple inversion of an algebraic equation. If the structure is axisymmetric with rotation-axis perpendicular to the line of sight, the magnitude of the disturbance can be measured through inversion of a non-singular square matrix. Here we report upon the extension of this work toward measuring the magnitude of a fully three-dimensional disturbance. This is done by analysing images from two perspectives through the test section and using inversion tomography techniques to reconstruct the disturbance field. The results are tested against theoretical predictions and experimental measurements.

  6. Three-dimensional printing physiology laboratory technology.

    PubMed

    Sulkin, Matthew S; Widder, Emily; Shao, Connie; Holzem, Katherine M; Gloschat, Christopher; Gutbrod, Sarah R; Efimov, Igor R

    2013-12-01

    Since its inception in 19th-century Germany, the physiology laboratory has been a complex and expensive research enterprise involving experts in various fields of science and engineering. Physiology research has been critically dependent on cutting-edge technological support of mechanical, electrical, optical, and more recently computer engineers. Evolution of modern experimental equipment is constrained by lack of direct communication between the physiological community and industry producing this equipment. Fortunately, recent advances in open source technologies, including three-dimensional printing, open source hardware and software, present an exciting opportunity to bring the design and development of research instrumentation to the end user, i.e., life scientists. Here we provide an overview on how to develop customized, cost-effective experimental equipment for physiology laboratories.

  7. Quantum interferometry with three-dimensional geometry

    PubMed Central

    Spagnolo, Nicolò; Aparo, Lorenzo; Vitelli, Chiara; Crespi, Andrea; Ramponi, Roberta; Osellame, Roberto; Mataloni, Paolo; Sciarrino, Fabio

    2012-01-01

    Quantum interferometry uses quantum resources to improve phase estimation with respect to classical methods. Here we propose and theoretically investigate a new quantum interferometric scheme based on three-dimensional waveguide devices. These can be implemented by femtosecond laser waveguide writing, recently adopted for quantum applications. In particular, multiarm interferometers include “tritter” and “quarter” as basic elements, corresponding to the generalization of a beam splitter to a 3- and 4-port splitter, respectively. By injecting Fock states in the input ports of such interferometers, fringe patterns characterized by nonclassical visibilities are expected. This enables outperforming the quantum Fisher information obtained with classical fields in phase estimation. We also discuss the possibility of achieving the simultaneous estimation of more than one optical phase. This approach is expected to open new perspectives to quantum enhanced sensing and metrology performed in integrated photonics. PMID:23181189

  8. Three-dimensional printing physiology laboratory technology

    PubMed Central

    Sulkin, Matthew S.; Widder, Emily; Shao, Connie; Holzem, Katherine M.; Gloschat, Christopher; Gutbrod, Sarah R.

    2013-01-01

    Since its inception in 19th-century Germany, the physiology laboratory has been a complex and expensive research enterprise involving experts in various fields of science and engineering. Physiology research has been critically dependent on cutting-edge technological support of mechanical, electrical, optical, and more recently computer engineers. Evolution of modern experimental equipment is constrained by lack of direct communication between the physiological community and industry producing this equipment. Fortunately, recent advances in open source technologies, including three-dimensional printing, open source hardware and software, present an exciting opportunity to bring the design and development of research instrumentation to the end user, i.e., life scientists. Here we provide an overview on how to develop customized, cost-effective experimental equipment for physiology laboratories. PMID:24043254

  9. Survey Of Three-Dimensional Television

    NASA Astrophysics Data System (ADS)

    Butterfield, James F.

    1980-06-01

    Since the introduction of television, various types of three-dimensional video systems have been used for industrial, medical, educational and entertainment purposes. The systems can be divided into two classes: (1) Stereoscopic Video Systems, which require special glasses or viewing aids; (2) Autostereoscopic Video Systems, which do not require glasses and are viewed by free vision. The two or more images required for these displays are picked-up by stereo optics with a single camera and multiplexed on a single communi-cation channel or they are picked up by two or more cameras utilizing an individual channel for each camera. One or more CRT's with stereo optics are employed in the receiver. The stereoscopic display provides the viewer with added realism and spacial information not available in any other manner. For entertainment purposes, the 3D picture enhances almost any program, including sports, drama and news. Typical industrial applications are for: remote viewing in connection with the remote driving of vehicles or operating manipulators; educational studies of solid geometry and atomic structure; and medical studies of surgical procedures. Stereo video also is being used in connection with microscopic optics to provide a stereo video microscope which has numerous advantages over a conventional optical microscope.

  10. Lattice Boltzmann Methods Applied to Three-Dimensional Virtual Cores Constructed from Digital Optical Borehole Images of a Karst Carbonate Aquifer

    NASA Astrophysics Data System (ADS)

    Lee, J. S.; Sukop, M. C.; Cunningham, K. J.

    2008-05-01

    Recovery of whole-core samples from macroporous karst carbonate is nearly impossible with conventional drilling technology. Thus, the most porous part of coreholes drilled in karst systems rarely yield whole-core samples. The consequent lack of samples for measurement of fluid-flow properties in karst carbonate aquifers impedes characterization of ground-water flow within these systems. This study uses advanced modeling techniques together with geophysical corehole data acquired from the karst carbonate Biscayne aquifer of southeastern Florida, USA, to explore a combination of innovative technologies designed to compensate for the lack of macroporous whole-core sample data. Specifically, these methods are being used to better understand the ground-water flow regime in the Biscayne aquifer. In this study, digital optical borehole image logs were compiled for test coreholes that penetrate the rocks of the Biscayne aquifer. The borehole image data were then processed to map the 3-D distribution of macropores and rock matrix present on the borehole walls using Stanford geostatistical software (SGeMS). The SGeMS program was used to compute variograms that were used as input for a computer simulation. The simulation results provided virtual 3-D renderings of the complex karst macropore network of the Biscayne aquifer that statistically replicate the borehole wall image data. These renderings provided 3-D visual records of areas of the aquifer that are composed of a carbonate eogenetic macropore system dominated by centimeter-scale vugs produced by fossil molds and voids associated with trace fossils. The vugs can coalesce over broad areas in the Biscayne aquifer to form laterally persistent zones of preferential ground-water flow. Lattice Boltzmann methods (LBMs) were used to measure the intrinsic permeability of the 3-D aquifer renderings. When using LBMs the rock matrix was assumed to be a nonporous media, thus permeability was only measured within the network of

  11. A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers.

    PubMed

    Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F

    2016-07-01

    In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK.

  12. A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers.

    PubMed

    Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F

    2016-07-01

    In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK. PMID:27018144

  13. Three-dimensional range imaging apparatus and method

    NASA Technical Reports Server (NTRS)

    Scott, Vibart Stan (Inventor); Blair, James Bryan (Inventor); Izquierdo, Luis R. (Inventor)

    2011-01-01

    A three-dimensional range imager includes a light source for providing a modulated light signal, a multiplexer, an optical fiber connecting the light source to the multiplexer, a plurality of optical fibers connected at first ends to the multiplexer and at second ends to a first fiber array, and a transmitter optic disposed adjacent the first fiber array for projecting a pixel pattern of the array onto a target.

  14. Electron tomography, three-dimensional Fourier analysis and colour prediction of a three-dimensional amorphous biophotonic nanostructure

    PubMed Central

    Shawkey, Matthew D.; Saranathan, Vinodkumar; Pálsdóttir, Hildur; Crum, John; Ellisman, Mark H.; Auer, Manfred; Prum, Richard O.

    2009-01-01

    Organismal colour can be created by selective absorption of light by pigments or light scattering by photonic nanostructures. Photonic nanostructures may vary in refractive index over one, two or three dimensions and may be periodic over large spatial scales or amorphous with short-range order. Theoretical optical analysis of three-dimensional amorphous nanostructures has been challenging because these structures are difficult to describe accurately from conventional two-dimensional electron microscopy alone. Intermediate voltage electron microscopy (IVEM) with tomographic reconstruction adds three-dimensional data by using a high-power electron beam to penetrate and image sections of material sufficiently thick to contain a significant portion of the structure. Here, we use IVEM tomography to characterize a non-iridescent, three-dimensional biophotonic nanostructure: the spongy medullary layer from eastern bluebird Sialia sialis feather barbs. Tomography and three-dimensional Fourier analysis reveal that it is an amorphous, interconnected bicontinuous matrix that is appropriately ordered at local spatial scales in all three dimensions to coherently scatter light. The predicted reflectance spectra from the three-dimensional Fourier analysis are more precise than those predicted by previous two-dimensional Fourier analysis of transmission electron microscopy sections. These results highlight the usefulness, and obstacles, of tomography in the description and analysis of three-dimensional photonic structures. PMID:19158016

  15. Radial Stellar Pulsation and Three-dimensional Convection. IV. Full Amplitude Three-dimensional Solutions

    NASA Astrophysics Data System (ADS)

    Geroux, Christopher M.; Deupree, Robert G.

    2015-02-01

    Three-dimensional hydrodynamic simulations of full amplitude RR Lyrae stars have been computed for several models across the instability strip. The three-dimensional nature of the calculations allows convection to be treated without reference to a phenomenological approach such as the local mixing length theory. Specifically, the time-dependent interaction of large-scale eddies and radial pulsation is controlled by conservation laws, while the effects of smaller convective eddies are simulated by an eddy viscosity model. The light amplitudes for these calculations are quite similar to those of our previous two-dimensional calculations in the middle of the instability strip, but somewhat lower near the red edge, the fundamental blue edge, and for the one first overtone model we computed. The time-dependent interaction between the radial pulsation and the convective energy transport is essentially the same in three dimensions as it is in two dimensions. There are some differences between the light curves of the two- and three-dimensional simulations, particularly during decreasing light. Reasons for the differences, both numerical and physical, are explored.

  16. RADIAL STELLAR PULSATION AND THREE-DIMENSIONAL CONVECTION. IV. FULL AMPLITUDE THREE-DIMENSIONAL SOLUTIONS

    SciTech Connect

    Geroux, Christopher M.; Deupree, Robert G.

    2015-02-10

    Three-dimensional hydrodynamic simulations of full amplitude RR Lyrae stars have been computed for several models across the instability strip. The three-dimensional nature of the calculations allows convection to be treated without reference to a phenomenological approach such as the local mixing length theory. Specifically, the time-dependent interaction of large-scale eddies and radial pulsation is controlled by conservation laws, while the effects of smaller convective eddies are simulated by an eddy viscosity model. The light amplitudes for these calculations are quite similar to those of our previous two-dimensional calculations in the middle of the instability strip, but somewhat lower near the red edge, the fundamental blue edge, and for the one first overtone model we computed. The time-dependent interaction between the radial pulsation and the convective energy transport is essentially the same in three dimensions as it is in two dimensions. There are some differences between the light curves of the two- and three-dimensional simulations, particularly during decreasing light. Reasons for the differences, both numerical and physical, are explored.

  17. Three-Dimensional Imaging of Lipid Gene-Carriers: Membrane Charge Density Controls Universal Transfection Behavior in Lamellar Cationic Liposome-DNA Complexes

    PubMed Central

    Lin, Alison J.; Slack, Nelle L.; Ahmad, Ayesha; George, Cyril X.; Samuel, Charles E.; Safinya, Cyrus R.

    2003-01-01

    Cationic liposomes (CLs) are used worldwide as gene vectors (carriers) in nonviral clinical applications of gene delivery, albeit with unacceptably low transfection efficiencies (TE). We present three-dimensional laser scanning confocal microscopy studies revealing distinct interactions between CL-DNA complexes, for both lamellar LαC and inverted hexagonal HIIC nanostructures, and mouse fibroblast cells. Confocal images of LαC complexes in cells identified two regimes. For low membrane charge density (σM), DNA remained trapped in CL-vectors. By contrast, for high σM, released DNA was observed in the cytoplasm, indicative of escape from endosomes through fusion. Remarkably, firefly luciferase reporter gene studies in the highly complex LαC-mammalian cell system revealed an unexpected simplicity where, at a constant cationic to anionic charge ratio, TE data for univalent and multivalent cationic lipids merged into a single curve as a function of σM, identifying it as a key universal parameter. The universal curve for transfection by LαC complexes climbs exponentially over ≈ four decades with increasing σM below an optimal charge density (σM*), and saturates for \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\sigma}_{{\\mathrm{M}}}>{\\sigma}_{M}^{{^\\ast}}\\end{equation*}\\end{document} at a value rivaling the high transfection efficiency of HIIC complexes. In contrast, the transfection efficiency of HIIC complexes is independent of σM. The exponential dependence of TE on σM for LαC complexes, suggests the existence of a kinetic barrier against endosomal fusion, where an increase in σM lowers the barrier. In the saturated TE regime, for both LαC complexes and HIIC, confocal microscopy reveals the dissociation of lipid and DNA. However, the lipid-released DNA is

  18. Exciton condensation in microcavities under three-dimensional quantization conditions

    SciTech Connect

    Kochereshko, V. P. Platonov, A. V.; Savvidis, P.; Kavokin, A. V.; Bleuse, J.; Mariette, H.

    2013-11-15

    The dependence of the spectra of the polarized photoluminescence of excitons in microcavities under conditions of three-dimensional quantization on the optical-excitation intensity is investigated. The cascade relaxation of polaritons between quantized states of a polariton Bose condensate is observed.

  19. Three-dimensional measurements of fatigue crack closure

    NASA Technical Reports Server (NTRS)

    Ray, S. K.; Grandt, A. F., Jr.

    1984-01-01

    Fatigue crack growth and retardation experiments conducted in polycarbonate test specimen are described. The transparent test material allows optical interferometry measurements of the fatigue crack opening (and closing) profiles. Crack surface displacements are obtained through the specimen thickness and three dimensional aspects of fatigue crack closure are discussed.

  20. Fiber optics for controls

    NASA Astrophysics Data System (ADS)

    Seng, Gary T.

    1987-11-01

    The challenge of those involved in control-system hardware development is to accommodate an ever-increasing complexity in aircraft control, while limiting the size and weight of the components and improving system reliability. A technology that displays promise towards this end is the area of fiber optics for controls. The primary advantages of employing optical fibers, passive optical sensors, and optically controlled actuators are weight and volume reduction, immunity from electromagnetic effects, superior bandwidth capabilities, and freedom from short circuits and sparking contacts. Since 1975, NASA Lewis has performed in-house, contract, and grant research in fiber optic sensors, high-temperature electro-optic switches, and fly-by-light control-system architecture. Passive optical sensor development is an essential yet challenging area of work and has therefore received much attention during this period. A major effort to develop fly-by-light control-system technology, known as the Fiber-Optic Control System Integration (FOCSI) program, was initiated in 1985 as a cooperative effort between NASA and DOD. Phase 1 of FOCSI, completed in 1986, was aimed at the design of a fiber-optic integrated propulsion/flight control system. Phase 2, yet to be initiated, will provide subcomponent and system development, and a system engine test. In addition to a summary of the benefits of fiber optics, the FOCSI program, sensor advances, and future directions in the NASA Lewis program will be discussed.

  1. Fiber optics for controls

    NASA Technical Reports Server (NTRS)

    Seng, Gary T.

    1987-01-01

    The challenge of those involved in control-system hardware development is to accommodate an ever-increasing complexity in aircraft control, while limiting the size and weight of the components and improving system reliability. A technology that displays promise towards this end is the area of fiber optics for controls. The primary advantages of employing optical fibers, passive optical sensors, and optically controlled actuators are weight and volume reduction, immunity from electromagnetic effects, superior bandwidth capabilities, and freedom from short circuits and sparking contacts. Since 1975, NASA Lewis has performed in-house, contract, and grant research in fiber optic sensors, high-temperature electro-optic switches, and fly-by-light control-system architecture. Passive optical sensor development is an essential yet challenging area of work and has therefore received much attention during this period. A major effort to develop fly-by-light control-system technology, known as the Fiber-Optic Control System Integration (FOCSI) program, was initiated in 1985 as a cooperative effort between NASA and DOD. Phase 1 of FOCSI, completed in 1986, was aimed at the design of a fiber-optic integrated propulsion/flight control system. Phase 2, yet to be initiated, will provide subcomponent and system development, and a system engine test. In addition to a summary of the benefits of fiber optics, the FOCSI program, sensor advances, and future directions in the NASA Lewis program will be discussed.

  2. Three-dimensional hologram display system

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  3. Three-Dimensional Reflectance Traction Microscopy

    PubMed Central

    Jones, Christopher A. R.; Groves, Nicholas Scott; Sun, Bo

    2016-01-01

    Cells in three-dimensional (3D) environments exhibit very different biochemical and biophysical phenotypes compared to the behavior of cells in two-dimensional (2D) environments. As an important biomechanical measurement, 2D traction force microscopy can not be directly extended into 3D cases. In order to quantitatively characterize the contraction field, we have developed 3D reflectance traction microscopy which combines confocal reflection imaging and partial volume correlation postprocessing. We have measured the deformation field of collagen gel under controlled mechanical stress. We have also characterized the deformation field generated by invasive breast cancer cells of different morphologies in 3D collagen matrix. In contrast to employ dispersed tracing particles or fluorescently-tagged matrix proteins, our methods provide a label-free, computationally effective strategy to study the cell mechanics in native 3D extracellular matrix. PMID:27304456

  4. Heat, Moisture, and Momentum Budgets of Isolated Deep Midlatitude and Tropical Convective Clouds as Diagnosed from Three-Dimensional Model Output. Part I: Control Experiments.

    NASA Astrophysics Data System (ADS)

    Schlesinger, Robert E.

    1994-12-01

    This project uses a three-dimensional anelastic cloud model with a simple ice phase parameterization to evaluate the feedback between isolated deep convective clouds and their near surroundings. The horizontal Reynolds averaging approach of Anthes is adopted to diagnose the vertical profiles of the individual budget terms for heat, moisture, and horizontal momentum, as well as the resultant effects of each budget as defined by apparent sources or sinks. The averaging area, 33.75 km on a side, is comparable to one grid cell for typical mesoscale numerical weather prediction models.Two comparative simulations are run, one for a severe Oklahoma thunderstorm in strong vertical wind shear and the other for a tropical Atlantic cumulonimbus in much weaker shear. The midlatitude cloud evolves to a vigorous quasi-steady mature stage with several supercell characteristics including an erect large-diameter updraft, a strong and vertically extensive mesolow, and a well-developed highly asymmetric cold pool that spreads rapidly. In contrast, the tropical updraft is much narrower and slower with a shallow weak midlevel mesolow, leans markedly downshear, and evolves early into slow decay modulated by bubblelike pulsations, while the cold pool is weak and quasi-circular and spreads slowly.There are several similarities between corresponding budgets in the two runs. Most notably: 1) The heat and moisture budgets are dominated by condensation, which is maximized in the midtroposphere. 2) The horizontal pressure gradient force dominates the momentum budget. 3) Vertical eddy transport (flux divergence) is highly important to each budget. Thermodynamically, it acts to mainly cool and dry the lower troposphere, while warming and moistening the upper troposphere, though with a lower crossover level for moisture than for heat. 4) The altitudes of the peak apparent heat sources are determined by the vertical eddy transport of heat. 5) Net evaporation has 40% as much amplitude as the

  5. Three-dimensional diamagnetic particle deflection in ferrofluid microchannel flows

    PubMed Central

    Liang, Litao; Zhu, Junjie; Xuan, Xiangchun

    2011-01-01

    Magnetic field-induced particle manipulation is a promising technique for biomicrofluidics applications. It is simple, cheap, and also free of fluid heating issues that accompany other common electric, acoustic, and optical methods. This work presents a fundamental study of diamagnetic particle motion in ferrofluid flows through a rectangular microchannel with a nearby permanent magnet. Due to their negligible magnetization relative to the ferrofluid, diamagnetic particles experience negative magnetophoresis and are repelled away from the magnet. The result is a three-dimensionally focused particle stream flowing near the bottom outer corner of the microchannel that is the farthest to the center of the magnet and hence has the smallest magnetic field. The effects of the particle’s relative position to the magnet, particle size, ferrofluid flow rate, and concentration on this three-dimensional diamagnetic particle deflection are systematically studied. The obtained experimental results agree quantitatively with the predictions of a three-dimensional analytical model. PMID:22662037

  6. Biodynamic profiling of three-dimensional tissue growth techniques

    NASA Astrophysics Data System (ADS)

    Sun, Hao; Merrill, Dan; Turek, John; Nolte, David

    2016-03-01

    Three-dimensional tissue culture presents a more biologically relevant environment in which to perform drug development than conventional two-dimensional cell culture. However, obtaining high-content information from inside three dimensional tissue has presented an obstacle to rapid adoption of 3D tissue culture for pharmaceutical applications. Biodynamic imaging is a high-content three-dimensional optical imaging technology based on low-coherence interferometry and digital holography that uses intracellular dynamics as high-content image contrast. In this paper, we use biodynamic imaging to compare pharmaceutical responses to Taxol of three-dimensional multicellular spheroids grown by three different growth techniques: rotating bioreactor, hanging-drop and plate-grown spheroids. The three growth techniques have systematic variations among tissue cohesiveness and intracellular activity and consequently display different pharmacodynamics under identical drug dose conditions. The in vitro tissue cultures are also compared to ex vivo living biopsies. These results demonstrate that three-dimensional tissue cultures are not equivalent, and that drug-response studies must take into account the growth method.

  7. Three-dimensional periodic chiral sculptured thin films

    NASA Astrophysics Data System (ADS)

    Venugopal, Vijayakumar C.

    2013-01-01

    Sculptured thin films (STFs) are nano-engineered materials that have controllable porosity, structural chirality, and periodicity in one, two, or three dimensions. They have been exploited in developing optical elements such as thin-film filters, polarizers, sensors, and waveguides for integrated optics. A grating theory-based modeling approach for STFs as fully three-dimensional (3-D) periodic structures is developed. Input for this model consists of a structural parameter set that is easily accessible experimentally. This parameter set is common to evaluating STFs from a fabrication as well as modeling perspective and thus furnishes a basis for developing appropriate process monitoring and control methods necessary for successful commercial production. Using the proposed model, a quantitative understanding of the limits of applicability of traditional modeling methods for STFs and guidelines for robust design of STF-based devices are developed. This knowledge gained is applied to explore STFs in two illustrative examples: (1) as a notch filter and (2) as a 3-D photonic crystal.

  8. Wavefront shaping based on three-dimensional optoacoustic feedback

    NASA Astrophysics Data System (ADS)

    Deán-Ben, X. L.; Estrada, Héctor; Ozbek, Ali; Razansky, Daniel

    2015-07-01

    Wavefront shaping techniques have recently evolved as a promising tool to control the light distribution in optically-scattering media. These techniques are based on spatially-modulating the phase of an incident light beam to create positive interference (focusing) at specific locations in the speckle pattern of the scattered wavefield. The optimum phase distribution (mask) of the spatial light modulator that allows focusing at the target location(s) is determined iteratively by monitoring the light intensity at such target. In this regard, optoacoustic (photoacoustic) imaging may provide the convenient advantage of simultaneous feedback information on light distribution in an entire region of interest. Herein, we showcase that volumetric optoacoustic images can effectively be used as a feedback mechanism in an iterative optimization algorithm allowing controlling the light distribution after propagation through a scattering sample. Experiments performed with absorbing microparticles distributed in a three-dimensional region showcase the feasibility of enhancing the light intensity at specific points. The advantages provided by optoacoustic imaging in terms of spatial and temporal resolution anticipate new capabilities of wavefront shaping techniques in biomedical optics.

  9. Three Dimensional Illustrating--Three-Dimensional Vision and Deception of Sensibility

    ERIC Educational Resources Information Center

    Szállassy, Noémi; Gánóczy, Anita; Kriska, György

    2009-01-01

    The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena…

  10. Fiber optics for controls

    NASA Technical Reports Server (NTRS)

    Seng, Gary T.

    1990-01-01

    The design, development, and testing of a fiber optic integrated propulsion/flight control system for an advanced supersonic dash aircraft (flies at supersonic speeds for short periods of time) is the goal of the joint NASA/DOD Fiber Optic Control System Integration (FOCSI) program. Phase 1 provided a comparison of electronic and optical control systems, identified the status of current optical sensor technology, defined the aircraft sensor/actuator environment, proposed architectures for fully optical control systems, and provided schedules for development. Overall, it was determined that there are sufficient continued efforts to develop such a system. It was also determined that it is feasible to build a fiber optic control system for the development of a data base for this technology, but that further work is necessary in sensors, actuators, and components to develop an optimum design, fully fiber optic integrated control system compatible with advanced aircraft environments. Phase 2 is to design, construct, and ground test a fly by light control system. Its first task is to provide a detailed design of the electro-optic architecture.

  11. Three-dimensional laser window formation

    NASA Technical Reports Server (NTRS)

    Verhoff, Vincent G.

    1992-01-01

    The NASA Lewis Research Center has developed and implemented a unique process for forming flawless three-dimensional laser windows. These windows represent a major part of specialized, nonintrusive laser data acquisition systems used in a variety of compressor and turbine research test facilities. This report discusses in detail the aspects of three-dimensional laser window formation. It focuses on the unique methodology and the peculiarities associated with the formation of these windows. Included in this discussion are the design criteria, bonding mediums, and evaluation testing for three-dimensional laser windows.

  12. Investigation on the magneto-optical Voigt effects in surface plasmon modes and anisotropic photonic band gap in the three-dimensional magnetized plasma photonic crystals as the mixed polarized modes considered

    NASA Astrophysics Data System (ADS)

    Zhang, Hai-Feng; Liu, Shao-Bin; Ding, Guo-Wen

    2014-10-01

    In this paper, the magneto-optical Voigt effects in surface plasmon modes and anisotropic photonic band gaps (PBGs) of the three-dimensional (3D) magnetized plasma photonic crystals (MPPCs) with face-centered-cubic lattices are theoretically investigated based on the modified plane wave expansion (PWE) method, which are the homogeneous Te (tellurium) spheres immersed in the homogeneous magnetized plasma background, as the mixed polarized modes are considered. The more general condition is considered, and the anisotropic PBGs are not only for the extraordinary and ordinary modes but also for mixed polarized modes. The equations for computing such anisotropic PBGs are theoretically deduced. Theoretical simulations show that the anisotropic PBGs and a flatbands region can be observed in the dispersive curve. Compared to the similar 3D MPPCs containing the isotropic dielectric or uniaxial material spheres, the larger PBGs can be obtained as the extraordinary axis of the inserted uniaxial material is along the Г-H symmetry line although the region of flatbands is also different. However, the relative bandwidths of PBGs for such two cases are almost the same. The interesting properties of surface plasmon modes can also be found, which are that the upper edge of flatbands region cannot be tuned by the filling factor but can almost linearly increase on increasing the plasma frequency and plasma cyclotron frequency (the external magnetic field), respectively. The effects of the filling factor, plasma frequency and plasma cyclotron frequency on the anisotropic PBGs are investigated in detail, respectively. Theoretical calculations also show that such PBGs can be manipulated by the parameters as mentioned above.

  13. Hydrofocusing Bioreactor for Three-Dimensional Cell Culture

    NASA Technical Reports Server (NTRS)

    Gonda, Steve R.; Spaulding, Glenn F.; Tsao, Yow-Min D.; Flechsig, Scott; Jones, Leslie; Soehnge, Holly

    2003-01-01

    The hydrodynamic focusing bioreactor (HFB) is a bioreactor system designed for three-dimensional cell culture and tissue-engineering investigations on orbiting spacecraft and in laboratories on Earth. The HFB offers a unique hydrofocusing capability that enables the creation of a low-shear culture environment simultaneously with the "herding" of suspended cells, tissue assemblies, and air bubbles. Under development for use in the Biotechnology Facility on the International Space Station, the HFB has successfully grown large three-dimensional, tissuelike assemblies from anchorage-dependent cells and grown suspension hybridoma cells to high densities. The HFB, based on the principle of hydrodynamic focusing, provides the capability to control the movement of air bubbles and removes them from the bioreactor without degrading the low-shear culture environment or the suspended three-dimensional tissue assemblies. The HFB also provides unparalleled control over the locations of cells and tissues within its bioreactor vessel during operation and sampling.

  14. Optimized resolved rate control of seven-degree-of-freedom Laboratory Telerobotic Manipulator (LTM) with application to three-dimensional graphics simulation

    NASA Technical Reports Server (NTRS)

    Barker, L. Keith; Mckinney, William S., Jr.

    1989-01-01

    The Laboratory Telerobotic Manipulator (LTM) is a seven-degree-of-freedom robot arm. Two of the arms were delivered to Langley Research Center for ground-based research to assess the use of redundant degree-of-freedom robot arms in space operations. Resolved-rate control equations for the LTM are derived. The equations are based on a scheme developed at the Oak Ridge National Laboratory for computing optimized joint angle rates in real time. The optimized joint angle rates actually represent a trade-off, as the hand moves, between small rates (least-squares solution) and those rates which work toward satisfying a specified performance criterion of joint angles. In singularities where the optimization scheme cannot be applied, alternate control equations are devised. The equations developed were evaluated using a real-time computer simulation to control a 3-D graphics model of the LTM.

  15. Three-dimensional surgical simulation.

    PubMed

    Cevidanes, Lucia H C; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2010-09-01

    In this article, we discuss the development of methods for computer-aided jaw surgery, which allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3-dimensional surface models from cone-beam computed tomography, dynamic cephalometry, semiautomatic mirroring, interactive cutting of bone, and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intraoperative guidance. The system provides further intraoperative assistance with a computer display showing jaw positions and 3-dimensional positioning guides updated in real time during the surgical procedure. The computer-aided surgery system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training, and assessing the difficulties of the surgical procedures before the surgery. Computer-aided surgery can make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases.

  16. Three-Dimensional Icosahedral Phase Field Quasicrystal

    NASA Astrophysics Data System (ADS)

    Subramanian, P.; Archer, A. J.; Knobloch, E.; Rucklidge, A. M.

    2016-08-01

    We investigate the formation and stability of icosahedral quasicrystalline structures using a dynamic phase field crystal model. Nonlinear interactions between density waves at two length scales stabilize three-dimensional quasicrystals. We determine the phase diagram and parameter values required for the quasicrystal to be the global minimum free energy state. We demonstrate that traits that promote the formation of two-dimensional quasicrystals are extant in three dimensions, and highlight the characteristics required for three-dimensional soft matter quasicrystal formation.

  17. Interpenetration of a three-dimensional Cu(I) coordination framework controlled by adjusting the symmetry of its secondary building unit

    NASA Astrophysics Data System (ADS)

    Ren, Shi-Bin; Qiu, Zhang-Jian; Yan, Jun; Zhao, Song-Lin; Wu, Cheng-Lin; Jia, Wen-Ping; Han, De-Man; Liang, Hua-Ding

    2013-08-01

    Two new coordination polymers based on CuX (X = SCN, I) and L have been successfully prepared by solvothermal reactions: [Cu4I4L] (1) and [Cu4(SCN)4L] (2) (L = tetrakis(3-pyridyloxymethylene)methane), exhibiting a doubly-fold interpenetrating diamondlike framework for 1 and a noncatenated structure with infinite[Cu(SCN)]n chains for 2. Their structural analysis shows the symmetry matching of their secondary building unit (SBU) can effectively control their degree of interpenetration.

  18. The relationship between three-dimensional knee MRI bone shape and total knee replacement—a case control study: data from the Osteoarthritis Initiative

    PubMed Central

    Barr, Andrew J.; Dube, Bright; Hensor, Elizabeth M. A.; Kingsbury, Sarah R.; Peat, George; Bowes, Mike A.; Sharples, Linda D.

    2016-01-01

    Objective. There is growing understanding of the importance of bone in OA. Our aim was to determine the relationship between 3D MRI bone shape and total knee replacement (TKR). Methods. A nested case-control study within the Osteoarthritis Initiative cohort identified case knees with confirmed TKR for OA and controls that were matched using propensity scores. Active appearance modelling quantification of the bone shape of all knee bones identified vectors between knees having or not having OA. Vectors were scaled such that −1 and +1 represented the mean non-OA and mean OA shapes. Results. Compared to controls (n = 310), TKR cases (n = 310) had a more positive mean baseline 3D bone shape vector, indicating more advanced structural OA, for the femur [mean 0.98 vs −0.11; difference (95% CI) 1.10 (0.88, 1.31)], tibia [mean 0.86 vs −0.07; difference (95% CI) 0.94 (0.72, 1.16)] and patella [mean 0.95 vs 0.03; difference (95% CI) 0.92 (0.65, 1.20)]. Odds ratios (95% CI) for TKR per normalized unit of 3D bone shape vector for the femur, tibia and patella were: 1.85 (1.59, 2.16), 1.64 (1.42, 1.89) and 1.36 (1.22, 1.50), respectively, all P < 0.001. After including Kellgren–Lawrence grade in a multivariable analysis, only the femur 3D shape vector remained significantly associated with TKR [odds ratio 1.24 (1.02, 1.51)]. Conclusion. 3D bone shape was associated with the endpoint of this study, TKR, with femoral shape being most associated. This study contributes to the validation of quantitative MRI bone biomarkers for OA structure-modification trials. PMID:27185958

  19. Three-dimensionally ordered array of air bubbles in a polymer film

    NASA Technical Reports Server (NTRS)

    Srinivasarao, M.; Collings, D.; Philips, A.; Patel, S.; Brown, C. S. (Principal Investigator)

    2001-01-01

    We report the formation of a three-dimensionally ordered array of air bubbles of monodisperse pore size in a polymer film through a templating mechanism based on thermocapillary convection. Dilute solutions of a simple, coil-like polymer in a volatile solvent are cast on a glass slide in the presence of moist air flowing across the surface. Evaporative cooling and the generation of an ordered array of breath figures leads to the formation of multilayers of hexagonally packed water droplets that are preserved in the final, solid polymer film as spherical air bubbles. The dimensions of these bubbles can be controlled simply by changing the velocity of the airflow across the surface. When these three-dimensionally ordered macroporous materials have pore dimensions comparable to the wavelength of visible light, they are of interest as photonic band gaps and optical stop-bands.

  20. Microperiodic structures: Direct writing of three-dimensional webs

    NASA Astrophysics Data System (ADS)

    Gratson, Gregory M.; Xu, Mingjie; Lewis, Jennifer A.

    2004-03-01

    Applications are emerging that require the creation of fine-scale structures in three dimensions - examples include scaffolds for tissue engineering, micro-fluidic devices and photonic materials that control light propagation over a range of frequencies. But writing methods such as dip-pen nanolithography and ink-jet printing are either confined to two dimensions or beset by wetting and spreading problems. Here we use concentrated polyelectrolyte inks to write three-dimensional microperiodic structures directly without using masks. Our technique enables us to write arbitrary three-dimensional patterns whose features are nearly two orders of magnitude smaller than those attained with other multilayer printing techniques.